by D.P. Mellor
Although radar made it possible to detect distant objects through darkness and fog, optical instruments were still essential for seeking out and accurately locating the enemy at closer ranges, as well as for directing the aiming of shells, torpedoes, bombs and rockets. The fortunes of battle could be influenced by the quality of the optical instruments used for fire control. It is the opinion of one writer that the loss of so many British ships in the Battle of Jutland could, in some degree, be attributed to the high quality of the fire-control and range-finding equipment of the German Navy at that time.[1]
Increasing dependence on optical instruments of all kinds had gone hand in hand with the growing complexity and efficiency of weapons of war and, in 1939-45, had reached such a pitch that actions were often fought at distances where combatants were no longer visible to one another. As recently as the American Civil War, the range of guns was so limited that the only targets that could be attacked effectively were those that could be seen with the unaided eyes of men near the guns. In the interval between the American Civil War and the first world war the range and accuracy of guns had been increased to the extent that it became possible to attack even relatively small targets at ranges of up to 30 miles or more. During the war of 1939-45 most of the really effective artillery fire on land was directed by gunnery officers who, usually with the aid of binoculars, could see the target and speak by telephone to the guns miles away. These ranges demanded optical instruments of the highest quality, chief among which were the dial sight director and range-finder. The advent of the submarine, tank and aeroplane called for other instruments, such as the periscope, camera, stereoscope and bombsight.
Manufacture of optical instruments was restricted to highly industrialised countries.[2] At the end of the nineteenth century Germany held a dominant position in the optical field because her industry was not only centralised and well organised, but was powerfully supported by the state. British optical industry, on the other hand, with many fine achievements to its credit, was not so well organised and did not receive state aid until much later in the day. Not until the war of 1914-18 did really strong optical industries spring into being in Great Britain and the United States. The sudden demand for optical instruments of all kinds in Australia in the early part of the war of 1939-45 constituted what was, up to that time, probably one of the most exacting of the demands made on the scientific and manufacturing resources of the country.
Men with experience in the manufacture of optical instruments were amazingly few. At the highest Ievel, on the theory and design as well as on the practical side of optical instrument making, the Munitions Supply Laboratories had on their staff only one man with considerable experience, and that was Mr Esserman whose experience had been gained in the older optical centres, more especially those of Britain, towards the end of the first world war. In 1918 Mr A.E. Leighton had suggested to Mr Esserman that Australia should start building up an optical industry in order to avoid dependence on oversea sources of supply.[3] Acting on this advice Esserman took courses on the theory and design of optical instruments at the Northampton Institute and at the Imperial College, London, which housed the first Department of Applied Optics established outside Germany. In both places Esserman studied under men of the highest reputation and experience in optics. On completing his studies he returned to Australia to take up a position in the Munitions Supply Laboratories, of which he later became Assistant Superintendent. In this capacity he supervised the repair of optical instruments for the army, designed modifications of certain short-base range-finders, and worked on the problem of fitting graticules to binoculars.
The first world war has, from a scientific point of view, often been called a "chemists' war" and the second world war a "physicists' war". Whatever the truth of these generalisations, it is certain that during the late nineteen-thirties physicists in universities and other research institutions of Great Britain and Australia foresaw that they were likely to play an important part in any future conflict and were not only on the alert but in many instances actively engaged in investigations likely to be of use in war, some time before its outbreak.
Early in August 1939, for example, members of the Australian Branch of the Institute of Physics, recognising that they might soon be called upon to do work of importance in national defence, met in Melbourne to consider possible courses of action. One result of their deliberations was a letter to the Prime Minister, Mr Menzies from the President of the institute, Professor Laby, and the Secretary, Professor Ross , suggesting that a consultative committee should be set up to advise the Government on matters relating to physics. Though the Prime Minister expressed his appreciation of the institute's offer, little came of it for some time. At a meeting held soon after the outbreak of war between the officers of the Institute of Physics and the Department of Supply and Development, a government spokesman stated that "while foreseen developments were well provided for, new developments might arise at any moment and the discussion had indicated lines on which immediate action could be taken as occasion demanded". The new developments followed some months later, when in June 1940 Australia was thrown almost entirely on her own resources. When the Directorate of Ordnance Production first embarked on the manufacture of the 2-pounder anti-tank gun the intention was to rely on the United Kingdom for the necessary optical equipment; similar plans had been made for the 25-pounder and the 3.7-inch anti-aircraft guns. These arrangements were no longer practicable. The inability of Britain and the United States to supply any optical equipment whatever caused grave anxiety, for without telescopic sights these guns could not be accurately aimed except at point-blank range. Faced with this crisis, the Director of Ordnance Production, Mr Hartnett, called the physicists together on 26th June 1940 to discuss the possibility of making sighting telescopes and dial sights in Australia.
The meeting led to the formation of a body initially called the
Optical Munitions Panel, a title later changed to the Scientific
Instruments and Optical Panel. At the time of its formation there was
no single centralised research institution in the Commonwealth capable
of advising the Department of Munitions on all the intricate problems
likely to arise in any attempt to make optical instruments. It is true,
a beginning had been made at the Munitions Supply Laboratories to study
the problems of manufacture of telescopes, but the task that lay before
the country was much too complicated and extensive to be undertaken
with the resources of those laboratories alone. The position in regard
to the possibilities of manufacture was much the same as in the case of
aircraft and torpedoes. Facilities or potential facilities lay
scattered throughout the main cities of the Commonwealth - in
laboratories, observatories and in spectacle and glass factories. There
was no time to set up a single optical manufacturing centre. In spite
of the fact that it might call for an immense coordination of effort,
it was a much more economical procedure to use men and machines
wherever they were to be found. The principal task of the
panel was to advise the Directorate of Ordnance Production on the
scientific and technical problems likely to arise in making optical
muitions and also to give assistance to firms and annexes selected or
established for their manufacture. Membership of the panel, which first
met on 23rd July 1940, was as follows:
The panel was enlarged from time to time. Members were drawn from
all parts of the Commonwealth: from government laboratories such as
Munitions Supply, National Standards and the Commonwealth Solar
Observatory; from the armed forces, and from the physics departments of
the Australian universities. All university members except the
secretary served in an honorary capacity; the secretary was paid by the
University of Melbourne throughout the tenure of his office and
received a small honorarium from the Commonwealth. Only two members of
the panel had had any experience in the design and construction of
optical instruments. Nevertheless, between them members of the panel
possessed a reserve of fundamental scientific knowledge and skill, the
existence of which was certainly not widely appreciated by the army or
by industry until war came. Even then it was some time before the value
of university departments of physics and government research
laboratories was fully recognised.
Some idea of the magnitude of the work that had to be
undertaken may be gathered from the fact that at the panel's second
meeting Lieut Colonel Adams submitted a list of urgently needed optical
instruments estimated as being likely to cost more than
£750,000.[11]
| Priority | Instrument | # Required |
|---|---|---|
| 1 | Sighting Telescope 24B | 3,500 |
| 2 | Height and range finder OB7 | 65 |
| Ring Sight telescope | 83 | |
| Identification telescope | 86 | |
| Dial sight No. 7 | 1,500 | |
| Director No. 12 | 2,500 | |
| Spirit Levels of various kinds | 3,000 | |
| 3 | Signalling telescopes | 1,200 |
| Range-finders No. 13 | 265 | |
| Binoculars No. 2 | 3,500 | |
| Stereoscopes | 250 | |
| Parallax bars | 50 |
This was a formidable program indeed for a country with no optical industry, for up to this time, apart from spectacles made from imported glass, not a single optical instrument worthy of the name had ever been manufactured on a commercial scale in Australia.
Soon after its formation the Director-General of Munitions, Mr Essington Lewis, asked the panel for "a comprehensive report on the cost and problem of producing optical munitions in Australia". The report was drawn up by the chairman and secretary, was submitted to Hartnett, and sent on to Mr Essington Lewis on 23rd August 1940. The report was most emphatic that great difficulties lay ahead. These anticipated difficulties were threefold:
Military optical instruments required metal parts made to a high
precision - at least as high as that demanded of instruments for
physics, astronomy and surveying. The panel's report listed the
tolerances or errors permitted in producing flat or curved surfaces in
different kinds of work, as giving some idea of the level of accuracy
and skill that would be called for. (These tolerances are shown in the
accompanying table.)
| Trade | Error permissable
along
1 inch of surface |
|---|---|
| Engineering | 1,000th of 1 inch |
| Aircraft | 10,000th of 1 inch |
| Spectacle Making | 10,000th of 1 inch |
| Higest Quality Optical | 1,000,000th of 1 inch |
However, optical munitions were so urgently needed that the War Cabinet decided in spite of the pessimism of the report that their manufacture should be undertaken forthwith. This involved three distinct stages:
That there would be difficulties everyone concerned agreed, but curiously enough no one anticipated the stage that was to offer the most serious obstacle.
It was obvious that before any progress could be made with the first
stage adequate supplies of optical glass must be obtained. The
importance of this part of the program may be gathered from a comment
by an American scientist in the first world war:
Glass of this quality had not previously been made in Australia, or
indeed anywhere outside Europe and North America. At first, as a
temporary expedient, efforts were made to substitute glass of the
quality used in spectacle lenses, and some telescopes were actually
made with this kind of glass. Orders for glass had been placed in
Britain and the United States but it soon became evident that these
countries could not be relied upon to spare sufficient from their needs
to meet Australia's requirements. The United States was at this period
suffering from a "glass famine". As it seemed quite likely that
Australia might soon be cut off from oversea supplies altogether,
Hartnett convinced the panel that the manufacture of optical glass
should be undertaken in Australia immediately. Some preliminary steps
had already been taken by Adams, who on 25th June 1940 had sounded
Australian Consolidated Industries on the possibility of their making
optical glass. This company, the only glass manufacturing firm in
Australia, was asked to consider the matter from "a purely national
point of view" and "in case of possible emergency". Its response was
prompt and entirely favourable.
The art of making optical glass consisted of melting
together certain ingredients to form a molten mass sufficiently fluid
to be readily and thoroughly stirred.[13] Almost the
entire process centred on procedures designed to ensure that the glass
was perfectly homogeneous, free from bubbles and flaws, and of exactly
the desired optical properties; only thus could the necessary
perfection of its optical behaviour be attained. Though this may sound
simple, in practice it called for the highest degree of control and
skill. Chemical purity of the raw materials, especially freedom from
traces of iron and titanium, was essential if the glass was to be
colourless and highly transparent.
When the United States entered the war in 1917 she found herself in
the very serious position of being almost entirely without an optical
glass industry. It is worth recalling briefly how these difficulties
were overcome, because of the influence her success was to have on
Australia's fortunes some thirty years later. For a long time much of
the technical detail of glassmaking was a closely guarded secret. The
seizure of patents did not help greatly to break down these secrets. In
1917 America was fortunate in having at the Geophysical Laboratories of
the Carnegie Institute of Washington a team of highly skilled
scientists who had been studying molten materials similar to optical
glass. Their work, directed in the first instance to purely academic
studies of rock-forming minerals, paid hand some dividends when the
knowledge so gained was applied to the problem of making optical glass.
The Americans were highly successful in producing optical glass, though
they did not succeed in producing all their requirements. Nevertheless,
mainly on account of the shrinking demand, America allowed her optical
glass industry to decline after the war of 1914-18, except in two
important centres. One of these, the Bureau of Standards at Washington,
D.C., carried on vitally important research and small-scale production
throughout the period between the wars.
One of the first committees set up by the Scientific
Instruments and Optical Panel was the Advisory Committee on Optical
Materials under the chairmanship of Professor Hartung [14] of Melbourne. Besides his purely chemical
interests, Hartung had long been deeply interested in optical
instruments and during his travels abroad had made short visits to the
optical glass factories of Zeiss at Jena and Chance Brothers at
Smethwick. Having kept a diary of these visits he was aware in a
general way of what was involved, chemically at all events, in the
manufacture of optical glass.
The Advisory Committee met early in August 1940 and
laid down a general plan of procedure, as a result of which Hartung
went to Sydney to consult with the technical staff of Australian
Consolidated Industries Ltd. [15] A plan of joint
work with the Chemistry Department of the University of Melbourne was
agreed upon. Through the help of A.C.I., which furnished advice and
essential equipment, a small gas-fired furnace was built in the
department and experimental work was in full swing in October 1940.
The basic raw materials not only of the glass but also of the pots
in which it was melted varied slightly from one source to another. For
example, no batch of sand was perfectly pure silicon dioxide; the
impurities present in any batch depended on the source or deposit from
which it was derived. Some impurities had a deleterious effect on the
glass, others had little or no effect. The suitability of a raw
material could be satisfactorily determined only by actual trials.
There were therefore two preliminary problems: the suitability of
Australian raw materials for the production of the glass, and the
suitability of Australian clays for the glass pots. By close
cooperation between A.C.I. who selected the clays and made small
experimental pots, and the Chemistry Department of the university,
whose staff undertook experimental meltings of various glass batches in
these pots and subsequent examination of the glasses produced, both
problems were solved in the laboratory by about the middle of 1941.
Translation of a small-scale operation to the large scale was seldom
just a problem of simple magnification of the operations. Troubles
might arise on the large scale which were not encountered in the
laboratory. It was difficult, if not impossible, to learn scientific
and technological processes from books and the patent literature alone.
This was especially true if time was important - as it was then. In the
transmission of scientific and industrial techniques from Europe and
America to Australia, gaining of direct experience was usually the
crucial step.
Since Australian Consolidated Industries did not have any men with
experience in the manufacture of optical glass, it was clear they had
either to import such a man or men, or send their own men overseas for
training. One of their first actions was to approach, through their
London representative, the firm of Chance Brothers for help. It was
learned that Chance Brothers could not make even one skilled man
available. All their resources were taxed to the utmost, not only with
their main works but with a shadow factory designed to replace the main
one if it were bombed out of action. They were also busy with an
extension of their activities to Canada.
Representatives of Australian Consolidated Industries in London then
attempted to reach an agreement with Chance Brothers whereby the
Australian firm could send men to England for training and at the same
time obtain drawings of plant and equipment and details of the latest
developments in the process for making optical glass. While these
negotiations were going on (towards the end of 1940) a meeting was held
in London of representatives from the Admiralty, the Canadian and
Australian Governments, Chance Brothers, and Australian Consolidated
Industries. It was suggested that Australia might cooperate with Canada
and thereby make it unnecessary to establish the manufacture of optical
glass here. Canada, it was said, was then in the course of
establishing, with the help of Chance Brothers, a government factory to
be known as Research Enterprises Ltd, for the manufacture of optical
munitions. This plant when completed would have the
advantage of proximity to one of the largest arsenals in the world and
access to the great technological help that could be given by the
United States. Chance Brothers expressed the view that, "having regard
to the problems of chemical and physical control as well as the highly
complicated details therein involved, Australian glass makers may be
under-estimating the difficulties they have to face". [16] The Australian High Commissioner in London, Mr
Bruce, summed up the position in a cable which read: "Have conferred
with Admiralty and Chance Brothers very emphatic that the making of
optical glass in Australia would be wasteful of war effort as it would
probably take four years before a successful production could be
achieved and the cost would probably be a million pounds accordingly
they discourage...."
When these suggestions were communicated to the Optical Panel, its
immediate reaction was to pass a unanimous resolution recommending that
the manufacture of optical glass in Australia should be undertaken
forthwith. The Government, actuated partly by this recommendation and
possibly even more strongly by suspicions about Japanese intentions in
the Pacific, gave Australian Consolidated Industries instructions to go
ahead with the project. The company made one more effort to get help
from Chance Brothers, but the terms imposed, including royalties and
post-war restrictions to be placed on any Australian optical glass
industry that might grow up, were not acceptable. A.C.I. therefore
decided to go ahead in its own way, finding out details of the process,
securing the necessary plant, and training men for the job.
The Australian glass industry had one thing in its
favour which should be mentioned: like the steel industry, it was
highly integrated. Whereas in other parts of the world firms
specialised in making one or two kinds of glassware, Australian
Consolidated Industries made a very wide range. Its experience in
making crystal glassware proved especially useful. Glass for crystal
ware had to be as nearly colourless as it was possible to make it, but
otherwise the requirements were no more exacting than those for
ordinary glass. An important advantage accruing from the company's wide
experience in glass manufacture was that it had, in the course of
years, made a thorough survey of the local supplies of raw material for
the industry. It still had to learn how to make optically homogeneous
glass of any specified chemical composition. The next step was to agree
to an arrangement whereby Mr Little [17], a member of
the technical staff, and Mr Grimwade [18], appointed
by the Department of Munitions, were sent by the Commonwealth
Government to Canada and the United States. In view of the earlier
negotiations and the Canadian firm's obligations to Chance Brothers, it
is not surprising that their visit to Research Enterprises Ltd in
Canada failed to lead to any agreement. Little and Grimwade then
visited firms in the United States, including Bausch and Lomb, Spencer
Lens, American Optical and Eastman Kodak, with no better
success. All these firms were willing to allow them to make an
inspection of the factories of the kind offered to tourists, but
nothing more. When one bears in mind the earlier failure to reach an
agreement with Chance Brothers it is difficult to understand now why
the Australian company should have expected to learn details without
cost from the private American firms. It reported that its
representatives spent three weeks "running everywhere into a brick wall
of secrecy"[19].
After this unbroken succession of failures, Little and
Grimwade almost gave up the idea of visiting the National Bureau of
Standards which, they believed, was merely engaged on experimental
work. As events proved, nothing was further from the truth. Far from
being unable to give advice to industry, they found "the National
Bureau of Standards particularly well fitted to render such service
inasmuch as it is the only scientific institution in the world which
has, entirely within its own organisation, complete facilities for
making an optical instrument beginning with the raw materials and
producing in turn the glass, the optical design, lenses and prisms, the
mechanical parts and finally the finished instruments"[20]. Moreover, during the years between the wars the
bureau had conducted extensive series of investigations on the relation
between the optical behaviour of glass and its chemical composition -
investigations which were published in great detail in its Journal
of Research and were of considerable help to makers of optical
munitions. Much of the veil of secrecy that before the
first world war had surrounded optical glass making, was lifted by the
National Bureau of Standards. There is no doubt that the help so freely
given by members of the staff of the bureau to Grimwade and Little and
to others who came later (Dr
Briggs and Mr Giovanelli
[21] of the National Standards Laboratory, and Mr
Rogers, Secretary of the Optical Panel) proved of the utmost value. For
this Australia owes the bureau a debt of gratitude. The reception given
to its representative is described in a report by Australian
Consolidated Industries:
These were tentative plans based on the company's own experience and
information from Wright's book. The company did not follow exactly the
American practices but where necessary adapted them to local
conditions, and succeeded in establishing for the Directorate of
Ordnance Production a well-designed annexe at Australian Window Glass
Pty Ltd, a subsidiary company of Australian Consolidated Industries.
The company's enterprise over many years had brought to light
excellent sources of raw materials. A remarkably good supply of silica
(sand) was procured from the aeolian deposits at Botany, Sydney -
literally at the company's back door. After processing, this sand was
considered to be one of the purest glass-making materials available
anywhere in the world. Other materials were gathered from all over the
Commonwealth: extremely pure calcite (to provide lime or calcium oxide)
from George's Plains near Bathurst, New South Wales, zinc oxide (from
Tasmania), lead oxide (from Port Pirie lead), soda ash (from Imperial
Chemical Industries' plant at Osborne, South Australia). Borax and
boric acid (from the United States), hydrated alumina and potassium
nitrate (from the United Kingdom) were the only materials that came
from outside Australia. Fortunately the company had accumulated
substantial stocks of these materials before the outbreak of war.
It was quite a straightforward matter to make up
accurately-proportioned mixtures of these pure materials, but it was
another matter to finish up with a glass of exactly the desired
composition. At the unusually high temperatures needed to secure
fluidity of the molten glass (about 1,500 degrees centigrade) some of
the ingredients were lost by being volatilised. Another difficulty,
caused by the greatly enhanced chemical activity of substances at high
temperatures, was to prevent the molten glass becorning contaminated
with substances from the walls of the clay pot in which it was being
heated. For this reason it was essential to have clay
pots made of refractory material that would introduce a minimum of
foreign matter into the glass. Not only had the refractories to be free
from undesirable impurities such as iron, they had also to have the
necessary strength and the ability to withstand continuous heating for
at least 24 hours at 1,500 degrees centigrade. Contamination was more
likely to arise in making optical than any other kind of glass, because
the proportion of molten glass exposed to contamination from the walls
of the pot was much greater [22]. Success in the
manufacture of optical glass depended to a very large extent on the
quality of the melting pots.
More than 100 different clays which over the years had been
collected from as far afield as Goulburn, Lake Macquarie, and
Wellington, New South Wales, were tested and eventually a suitable one
was found. Fabricating the pot itself called for experience and skill.
In the early days of optical glass making, such pots had been made by
hand and required a long time for drying - upwards of nine months in
the usual process. During the 1914-18 war a method for manufacturing
pots known as slip casting was devised at the National Bureau of
Standards. This method was now well known to the
Australian glass industry, which had been using it for several years to
manufacture special parts of ordinary glass furnaces. In slip casting,
clay of the consistency of porridge was poured into a special porous
mould and because of this a greatly reduced time for drying was
required. The successful solution of the problems relating to the
manufacture of clay pots owed much to Mr Death [23],
the expert in refractories at A.C.I. But the difficulties were not all
over with the solving of the problems of pot making.
To make the glass, a pot was charged with about half a ton of
mixture, placed in a furnace and slowly brought up to a temperature of
1,500 degrees centigrade. While at this high temperature the melt was
stirred mechanically by means of a clay rod. After the molten mass had
been made as homogeneous as possible, the pot and its contents were
allowed to cool very slowly. Controlled cooling to room temperature
took anything up to 96 hours. After the pot and its contents had
cooled, the mass of glass was broken up into chunks of different sizes,
care being taken not to shatter the glass unduly. The chunks were then
critically examined for imperfections, such as bubbles and striations
due to inhomogeneity of the glass. Those that passed the test were
carefully reheated, picked up on an iron rod, and transferred to a
clean metal surface where they were patted and rolled like dough.
Inclusions or folds were then snipped out and when the glass was of
approximately the right shape, and while it was still plastic, it was
cut to fit closely into the moulds designed for the particular
component and pressed into shape. Finally the glass was annealed. Here
again American help, in the form of instruments capable of
automatically controlling the heating and cooling to predetermined time
schedules, was invaluable.
No glass was ever entirely free from mechanical strains which
destroyed its optical homogeneity. For optical work these strains,
which must be reduced to a minimum, were released by taking the glass
up to a temperature just short of its softening point, and then
allowing it to cool very slowly over about six days. The rate of
cooling depended upon the size of the piece of glass: for the glass in
a large astronomical reflector such as the 200-inch, a period of up to
six months might be required for annealing.
As can easily be imagined, many of these operations called for
experience and skill. Although at the outset the Australian company did
not have a single man trained in optical glass processes and, it will
be recalled, failed in negotiations to have any of its men trained
overseas, no trained men were imported. In the event, it relied
entirely on its own men and experience and the details learned by
Little at the Bureau of Standards. American experience in the first
world war had been that it was extremely difficult for men who had been
trained in the production of plate glass, for example, to turn to the
production of optical glass. The Australian effort was made by men
whose main advantage was experience in the making of lead glass for
crystal ware. There were relatively few even of these. As so often
happened during the war, whatever totally unskilled labour happened to
be available had to be brought in and trained for the job. This was
done successfully, and on 21st September 1941 Australian Consolidated
Industries produced the first large-scale batch of optical glass ever
to be made in Australia.
This first melt, a borosilicate crown glass, passed
all the stringent tests laid down by the army authorities. Most of the
accurate measurement and testing of the optical properties of the
glass, such as refractive index and dispersion, were carried out by the
Physics Section of the National Standards Laboratory. The refractive
index of the first melt was within 0.002 of the required figure,
whereas specifications allowed a tolerance of 0.003. So it was that, by
the time the Pacific war began, Australia had an assured supply of
optical glass adequate to meet all the demands of the armed forces [24]. In spite of a late start she was only one month
behind Canadian Research Enterprises Ltd. Production was achieved
within about ten months of the decision to undertake it - instead of
the predicted four years - and at a cost of about £60,000 instead
of the predicted £1,000,000.
The supply of glass was adequate both in amount and in variety.
Within six months of the first output the production of five standard
types of optical glass had been perfected. In all some thirteen
different kinds of glass were made, including several special coloured
glasses for protecting the eyes against glare, and for conditioning
them to seeing in the dark, as will be described later. The company
claimed that by improving existing techniques the yield of glass was
increased from the 12 per cent customary in oversea commercial practice
to the extraordinary figure of 17 per cent. The extent of its output is
indicated in the following table showing the number of blanks produced.
(Blanks were lenses and prisms moulded roughly to the required final
shape.)
Military fire control apparatus includes
instruments of high precision, and as one of the integral parts of such
instruments optical glass must measure up to the same high standards of
precision. Upon it the quality of the image formed and the precision of
each setting of the sighting instrument is dependent. The lens designer
computes the shapes and positions of the several different lenses and
prisms in an optical instrument and arranges them along the line of
sight in such a way that the particular and inevitable defects or
aberrations are reduced to a minimum. The degree to which these
aberrations can be made negligible depends in large measure on the
kinds and quality of the glass available to the designer. It is
important therefore that the quality of the glass be of the best and
that a sufficient number of different types be at hand.[12]
. . . the officials of the Bureau did everything in their
power to provide him with data required. Their plant was thrown open to
him for detailed examination - details of glass composition, batch
formulae [lists of materials and their proportions that are melted
together to form glass], pot making technique, moulding procedure,
methods of inspection, annealing - nothing was withheld. Here then the
Australian was able to check and verify Australian Consolidated
Industries' blue prints of plants, processes and techniques which he
had carried with him from Australia.
| Tank periscopes | 10,000 |
| Dial sights | 68,000 |
| Anti-tank gun sights | 46,000 |
| Rifle sights | 39,000 |
| Cruiser-tank gun sights | 15,600 |
| Naval gun sighting telescopes | 8,600 |
| Anti-aircraft predictors | 8,400 |
| Aircraft identification telescopes | 3,300 |
A large amount of glass was supplied to forces other than
Australian:
| U.S.A. (blanks for dial sights) | 57,000 |
| N.Z. (various components) | 4,700 |
| India (slab glass) | 5,200 |
Specimens of every melt of glass were tested in thc Physics Section of the National Standards Laboratory, of which Dr Briggs was Officer-in-Charge. With most types of glass a very high degree of constancy of refractive index from melt to melt was achieved. For example, the greatest variation of the refractive index of eight melts of borosilicate crown glass from the average value of 1.51000 was 0.002. Some glasses were more successfully reproduced from melt to melt; others were not so well reproduced. By and large the reproducibility was satisfactory. Efficiency of annealing was also tested at the National Standards Laboratories with similar satisfactory results. Exacting tests, made to determine the degree of homogeneity, also showed that the glass was generally of a high quality. The verdict of the British Scientific Instrument Association given as a result of tests carried out at the request of the Admiralty, substantiates these statements: "All the specimens showed freedom from veins and other defects of this type. These specimens of Australian optical glass are in general of first class quality and the telescopic flint and borosilicate glasses are very good indeed."
Like many another wartime achievement, the making of
optical glass was the result of good team work. Special mention should
be made of Mr. Warren [25] and Mr Blakeney [26], but to do justice it would be necessary to name
all members of the technical staff of Australian Window Glass.
Having arranged for the production of adequate amounts of suitable glasses, the Directorate of Ordnance Production was ready to proceed to the next step: the manufacture of optical components, principally lenses and prisms [27]. The shapes and sizes of these were either given in specifications or, where entirely new instruments were required, they had to be calculated. Once size and shape were known, the blanks supplied by Australian Consolidated Industries had to be ground and polished to exactly those requirements.
Men with experience and skill in grinding and polishing glass to the accuracy required for instruments of high precision were very few indeed. The Commonwealth Solar Observatory was fortunate in having the services of Mr Lord [28], who had studied in Paris under Professor Fabry and had had practical experience in Czechoslovakia, and also of Mr Elwin [29], an amateur astronomer with much experience in optical glass working. Both men gave instructional courses, Lord on elements of optical computing, and Elwin on techniques of glass working. At the University of Melbourne Mr Dainty [30], who had gained considerable experience in grinding and polishing lens prisms in England some years before, gave much assistance in developing these techniques; he had in fact come to Australia from New Zealand for this purpose.
In January 1940 the Munitions Supply Laboratories sent Mr McNeil [31] to England to undergo a two-year course in optical design. McNeil found private manufacturers of optical instruments in England most cooperative - more so than the glass makers - and on his return in 1942 gave a considerable impetus to optical design. Towards the end of 1941 the same laboratories were able to arrange with Adam Hilger Ltd, a leading British firm making optical instruments, for the loan of a highly skilled glass worker who would establish workshop practice on a sound footing. He arrived early in 1942 and his assistance in the development of methods for making high-quality glass prisms and plane parallel glass plate, and in training men in these methods, was particularly valuable.
Lenses and prisms were for the most part made by men and women whose previous experience was limited to the much less exacting work of making spectacle lenses. The kind of polishing used for spectacle lenses did not lead to a sufficiently accurate surface, nor did the spectacle maker use test-plates and optical interference fringes to check his work. Entirely new techniques of pitch polishing (in place of felt polishing) and of lens testing had to be learned. By means of classes conducted at the Sydney and Melbourne Technical Colleges, together with the help of the Commonwealth Solar Observatory, the annexe at Hobart, and the Munitions Supply Laboratories, spectacle-lens workers and others were trained to the level of skill required. On the whole, employment of men with experience in spectacle-lens work was found to be satisfactory, there being very few who did not show some aptitude for the higher grade work. This was contrary to the experience in Great Britain during the first world war, where the same experiment did not work out at all satisfactorily. At least one firm in Australia decided to train women without any previous experience in glass work, and obtained excellent results.
The techniques of designing and manufacturing optical
instruments were also being developed in the Physics Section of the
National Standards Laboratory under Dr Briggs. The program included
setting up facilities for the design, construction, analysis and test
of optical instruments. Machines for optical lens making had been
ordered in 1939 and an optical shop under Mr Schaefer [32] was in operation by August 1941 for the production
of lenses, prisms and other optical components. An example of its work
was the design and production in large numbers of a four component lens
system for the lumi-gauge, an optical gauging instrument.
Once the lenses and prisms had been made it was necessary to have metal parts to hold and control their movements. Provision of these demanded mechanical construction of the highest accuracy. Skilled mechanics who could make the parts with adequate precision were rare, and considerable trouble was experienced in this phase of the work. Here was revealed a grave deficiency in Australia's resources of skilled man power and the cause of one of the most serious bottlenecks in producing optical munitions. There was also a scarcity of optical adjusters - men who assembled and adjusted the optical components in the mechanical frame work. At the outbreak of war only one man in Australia was found who had had experience of this kind of work [33], though many were trained later. Shortage of skilled mechanics and optical adjusters led the Optical Panel to advocate "that Australia in peacetime should maintain either in private industry or in Government workshops sufficient highly trained mechanics and instrument assemblers so that should the occasion again demand the rapid production of optical munitions there will not be the exasperating delays . . . which occurred" in the second world war.
The difficulties were accentuated by the general shortage of machine tools. At first certain instruments could not be made because contracting firms were unable to turn out metal structures with sufficient accuracy. The readings of a director, for example, had to be accurate to within two minutes of arc, a degree of precision called for only in high-grade scientific instruments, such as a surveyor's theodolite. After a great effort, for other industries were competing for the limited numbers of skilled men, enough were found in firms making wireless equipment, jewellery, totalisator equipment, typewriter accessories, and in all kinds of small engineering establishments, to carry through the work.
Similar troubles were experienced in finding men capable of
assembling all the parts to make the complete instrument. Contracting
firms entrusted with the work had had no experience in the assembling
of instruments and were often without the necessary testing devices,
such as collimators. Here the cooperating laboratories - the university
physics departments and the different government laboratories - did
excellent work in training instrument assemblers, lending suitable
testing instruments, and helping to devise methods for attacking
various problems. At first firms were sceptical of the ability of
scientists from university and government laboratories to help in
solving their problems, but eventually they became fully convinced.
In November 1939 practically the only machines capable of fashioning optical glass into accurate lenses and prisms were an odd assortment of grinding, polishing, edging and disc-cutting machines at Maribyrnong Supply Laboratories. Some machines arrived from England early in 1941, but the rest were made in Australia. The Australian Optical Company, Ltd, which came to be the largest manufacturer of optical munitions, made all its own machines. After many attempts the company's chief engineer succeeded in designing a machine which could grind lenses to the required accuracy. Then in association with others he designed a lens-blocking machine which simplified this intricate and important operation so greatly that unskilled and semi-skilled workers were able to produce many thousands of precision lenses each month.
Several excellent glass-working machines were designed and built in the Optical Annexe at Hobart [34]. There also the technique of using diamond dust in glass roughing and grinding was developed. Diamond dust mixed with dental amalgam was used in glass-cutting saws. In fact "the whole trend at Hobart was to treat glass grinding as if it was metal grinding and some of the glass grinders were just milling machines in which the glass was held in ingeniously designed jigs" [35]. Many diamond dust saws were later made at the University of Melbourne. Similar advances were made simultaneously but independently in oversea laboratories.
Improvements in glass polishing that had been achieved overseas by
the substitution of cerium oxide for rouge were quickly adopted in
Australia. First introduced in Europe in 1933, its use spread to Canada
and the United States in 1941 and thence to Australia. Substitution of
cerium oxide was an important innovation because it reduced the
polishing time to about half that required with rouge. At first
imported Canadian cerium oxide was used, but it was not long before the
Division of Industrial Chemistry, with its experience in the chemical
treatment of monazite, discovered the technique of making a highly
satisfactory cerium oxide containing polishing powder, and made the
process available to a commercial firm.
Nearly all instruments classified as optical munitions were telescopes of one kind or another, or contained telescopes as part of their make up. This being so it was not surprising that the first military instrument to be made on a large scale in Australia was a telescope. Since the story of this instrument is a typical one in so far as the general plan of operations was concerned, it will be told in some detail. By no means the most compilcated instrument undertaken, it did, however, have difficulties of its own because no others had been made before.
The first instrument the army asked for was the Sighting Telescope 24B designed to be used either on guns, mounted in a tank, or on anti-tank guns. It was therefore likely to be required in fairly large numbers, 3,500 being asked for in the first instance. Drawings and specifications (originally drawn up by the British War Office), together with a specimen instrument, were sent by the Ordnance Production Directorate to the Optical Panel. Members of the panel studied the way in which the instrument was intended to be used, what kind of performance was expected of it, and how it could be produced with the materials available. Here the first obstacle was encountered. The War Office description of the telescope stated clearly enough the magnification and general performance to be expected but gave no information about the kind of optical glass used or be radii of curvature and thickness of the lenses used [36]. The information had to be obtained by measurements on the specimen instrument. This would have been straightforward enough had the right kinds of optical glass been available, but at the time no really suitable optical glass was to be had and there was no alternative but to make do with the crown and flint glasses used for spectacle lenses. This meant redesigning the instrument to the extent of recalculating the sizes, shapes and positions of the lenses, a task carried out by Woolley at the Commonwealth Solar Observatory. Owing to the fact that the only spectacle flint glass procurable was in the form of blanks smaller than those called for in the specifications, be instrument had to be modified still further.
A model of the modified instrument - Sighting Telescope No. 124 (Aust) - was made at the Commonwealth Solar Observatory, and submitted to the panel for critical examination. Having been accepted by the panel in October 1940 it was next sent on to the army for tests and trials. Here it failed to satisfy requirements for use in tanks but was good enough to function as an efficient aiming instrument in an anti-tank gun. The panel then prepared drawings and specifications which were sent on to the Directorate of Ordnance Production with a recommendation that an "educational order" be placed with each of two contractors. The directorate, after consulting with the Boards of Area Management in Victoria and New South Wales, decided to place orders with the British Optical Company (Sydney) and the Australian Optical Company (Melbourne), both of which had had previous experience only in making spectacles.
By February 1941 both contractors had produced their first sighting telescopes. In the opinion of the Optical Panel the instruments were still far from perfection but their performance was sufficiently promising to encourage the hope that the contractors, with a little more experience, might make really satisfactory instruments. At all events, the panel was sufficiently optimistic to advise the Directorate of Ordnance Production to place an order at once for 1,000 instruments. This advice was taken.
One of the factors that handicapped the contractors in their first efforts to make the telescope was that they had no test plates for checking their lenses. After the Commonwealth Solar Obsenatory and other cooperating laboratories had come to their aid by making these gauges, they began to turn out satisfactory instruments, and by April 1942 some 900 telescopes had passed inspection. Rejections were very few indeed. Thus by the enthusiasm, ability and ingenuity of hundreds of men and women from many walks of life (for most workers had to be trained), the first military optical instruments in the history of Australia were produced. But their task was by no means over. Many other instruments, some much more difficult to make, were required. It would be impossible in reasonable compass to describe all the optical instruments made in this country during the next few years; they ranged from telescopes of all kinds, periscopes, range-finders, dial sights, parabolic searchlight reflectors, stereoscopes and bubbles (that is, spirit levels) to camera lenses. The procedures in the manufacture of each instrument were much the same.
Dial Sight No. 7, the second instrument in order of army priorities, was not only a complicated mechanical device but also complicated optically since it contained a telescope together with three prisms, two of which were roof prisms. These prisms had to be made with an accuracy that provided for error in aiming of no more than three minutes of arc. Here again lenses for the first instruments were made of spectacle glass but as soon as local optical glass became available the instrument was redesigned and became Dial Sight (Aust) Mark II.
In order to speed production of the mechanical parts of this instrument, an attempt was made to use the technique of die casting, a process in which a casting was formed by injecting molten alloy into a die under intense pressure. Castings made in this way reproduced the required dimensions to a high degree of accuracy, provided always that a suitable alloy was used. The attempt failed because the alloy chosen was not sufficiently stable or well produced. In other fields of activity die casting in Australia was a success, enabling the mass production of accurately formed metal objects that required no further machining. The failure in the manufacture of mechanical parts for the dial sight was not due to lack of zinc of the necessary 99.99 per cent purity for alloy making, since this grade of zinc was readily available from the Electrolytic Zinc Company at Risdon, Tasmania. Whatever the cause the fact remains that die casting for this work had to be abandoned. Ultimately the technique of making the metal parts of dial sights was mastered by J. W. Handley and Sons of Melbourne, and about 1,883 instruments complying fully with the specifications were made.
Range finder No.13 was a really difficult instrument, especially in its mechanical parts, and the task was made even more difficult by the fact that no War Office drawings were available and the necessary information had to be obtained by measuring and analysing a specimen instrument. The first contractor chosen for this range-finder, even after he had been given much technical assistance by the Munitions Supply Laboratories, failed to achieve the high standard of mechanical construction required. Eventually the contract was given to J. W. Handley and Sons, who, although they also encountered difficulties, did, by 1945, turn out range finders up to War Office specifications. By that time range finders were arriving from England.
Although searchlight mirrors were not the concern of the Optical Panel, it is appropriate to deal with them at this point. The first inquiries about the possibility of manufacturing them were made during August 1938, just before the Munich crisis. It was clear to the Australian Defence authorities that Britain would need all her resources and energy to put her own defences in order and that Australians must rely largely on their own efforts to meet their defence requirements. These were the considerations behind the exploratory inquiries made by the Royal Australian Engineers' establishment at George's Heights (Sydney) to Australian Consolidated Industries. In spite of these very early moves it was about three years before any mirrors were produced. The main reason for the long delay appears to have been the difficulty experienced by the company in obtaining sufficiently definite and satisfactory specifications to work upon and a clear idea of the number of mirrors actually required. The company's own story of the negotiations with the Department of Munitions gives the impression that the liaison between technical experts of the department and the company was not as satisfactory as it might have been. The company complained that the several successive specifications, obtained only after repeated inquiries on their part, were impossibly exacting and more appropriate to reflectors used in precision astronomical telescopes [37]. Some of the department's vagueness and hesitancy about the number of mirrors required appears to have been due to an uncertainty whether aluminium reflectors might not be more useful than glass ones because they would be relatively immune to destruction by machine-gun fire.
Until the end of the nineteenth century Germany had had a monopoly of the manufacture of searchlight mirrors. At the turn of the century Sir Charles Parsons, well known as a maker of astronomical telescopes and turbines, turned his attention to making searchlight mirrors. This he did so successfully that the firm of C. A. Parsons and Company of Newcastle-on-Tyne supplied more than 80 per cent of the reflectors used by the Allies during the first world war. It was substantially with Parsons' technique that mirrors were first made in Australia. After Australian Consolidated Industries had rejected the third specification sent in by the Department of Munitions, they had the good fortune to discover that Mr Coombes [38] of the Aeronautical Research Laboratory, Melbourne, had once been associated with C. A. Parsons and Company, and although he had not actually worked on the manufacture of searchlight mirrors, he was acquainted with the Parsons process. In June 1940 the Department of Supply and Development lent Coombes to the company. Working with the aid of notes and sketches made largely from memory, he was able to give some indication of the process used in England. These notes were later supplemented by Dr Briggs, who about this time was visiting the works of Messrs C. A. Parsons Ltd to study optical problems associated with setting up the Physics Section of the National Standards Laboratory. While there he was shown round the mirror section. On his return to Australia he found much of what he had confidentially learned from the English firm as an officer of the C.S.I.R. would be of considerable help to Australian Consolidated Industries. The C.S.I.R. immediately explained the circumstances to Messrs C. A. Parsons, and the firm generously gave full approval to Briggs' passing on to the Australians whatever information he could.
At this stage the company met another obstacle, namely that of obtaining a satisfactory supply of glass for the mirrors. For a company making as much glass as Australian Consolidated Industries did this may sound rather strange, but searchlight mirrors called for plate glass, which was not made anywhere in Australia. Plate glass was first rolled or drawn into shape and then ground and polished to remove surface imperfections. To set up machinery for making plate glass in Australia would have been most expensive, and for a while it seemed that if plate glass had to be imported it might be as well to import the reflectors themselves. However this suggestion was rejected because greater space would be occupied by a cargo of reflectors and a much greater loss would follow enemy action against the ship carrying them. Orders for heat-resisting borosilicate plate glass were finally placed on 7th March 1941 with the firm of Pilkingtons in England.
The method of making a mirror was simply to bend a sheet of softened plate glass to approximately the required shape by allowing it to sag into a mould paraboloid in shape. Sagging was assisted by slightly reducing the air pressure within the mould. When cooled, the curved glass was taken from the mould, annealed, and then ground and polished. It was covered with a film of silver backed by a protective coat of paint, and finally baked at a temperature of about 230 degrees centigrade for four hours. By the time the heat-resistant borosilicate glass arrived from England (in October 1941) sufficient experimental work had been done to enable the company to begin production. The first mirror was tested and approved on 13th January 1942, at the School of Military Engineering, Liverpool. Within a month it had been despatched to Port Moresby.
Thus, despite the difficulties encountered over three years in obtaining adequate specifications; despite the heartbreaking struggle to obtain government authority to undertake the manufacturing process and the delays in obtaining the necessary borosilicate glass from England, within two months of Japan's entry into the war with its immediate threat to Australia's north, the first of many Australian-produced reflectors was on its way to New Guinea. In all some 115 reflectors were made, every one of which satisfactorily passed army inspection.
An equally necessary searchlight component - the carbon rod used for forming the arc - was manufactured by Standard-Waygood Ltd of Sydney. For the graphite and cerium fluoride the firm relied upon imports, but the main ingredient, coke of a high degree of purity, was made from hard pitch supplied by the Australian Gas Light Company of Sydney. Altogether Standard-Waygood supplied more than 250,000 searchlight carbons.
Of the instruments made for the navy the most important was Naval Gun Sighting Telescope G.A.100, a copy of Royal Navy Instrument 353 A.H. With the help of several of the cooperating laboratories, the British Optical Company made about 450 of these telescopes.
[1] J.A. Borkin and C.A. Welsh,
Germany's Master Plan : The Story of an Industrial Offensive,
London (1943).
[2] Before the second world war
optical glass was manufactured in Britain, Germany, France, the United
States, Italy and Japan.
[3] Australia's peacetime
requirements of optical instruments were valued at about £750,000.
[4] Col G. H. Adams, MC, ED. (Served
1st AIF) Asst Director of Artillery AHQ, 1940-42. Wine merchant; of
Melbourne; b. Melbourne, 19 June 1886.
[5] Sir Kerr Grant, MSc. Prof of
Physics, Univ of Adelaide 1911-48. b. Bacchus Marsh, Vic, 10 Jun 1878.
[6] E.O. Hercus, DSc. (Served RNVR
1916-18.) Assoc Prof of Physics, Univ of Melbourne, since 1931. B.
Dunedin, NZ, 23 June 1891.
[7] E.L. Sayce. Assistant
Superintendent, Munitions Supply Laboratories, 1939-52. Of Melbourne;
b. Hawthorn, Vic, 20 Dec 1899.
[8] O.U. Vonwiller, BSc. Prof of
Physics, Univ of Sydney, 1923-46. b. Sydney, 18 Feb 1882.
[9] R. v.d.R. Woolley, OBE; FRS, MSc,
MA, PhD. Commonwealth Astronomer 1939-55; Chief Executive Officer, Army
Inventions Directorate, 1942-45; Astronomer Royal, Greenwich, England
since 1955. b. Weymouth, Eng, 24 April 1906.
[10] J.S. Rogers, MC; BA, DSc. (Served
1st AIF) Senior Lecturer in Physics, Univ of Melbourne 1924-46. Warden,
Mildura Branch, 1946-50, Dean of Graduate Studies since 1950. b.
Beaconsfield, Tas, 18 June 1893.
[11] This estimate was made in the
"Report on Cost and Production of Optical Munitions" to the
Director-General of Munitions by the Chairman of the Optical Munitions
Panel.
[12] F.E. Wright, The Manufacture
of Optical Glass and Optical Systems. Ordnance Dept Document 203.
Washington. Govt Printing Office (1921).
[13] The ingredients used depended
upon the kind of glass required. They included silica (sand) and the
oxides of such metals as sodium, potassium, calcium and aluminium. In
addition to the oxides of these metals certain other oxides were used
to impart special properties. These included oxides of lead, zinc,
barium, arsenic and boron.
[14] E.J. Hartung, DSc. Lecturer and
demonstrator in Chemistry, Univ of Melbourne 1919, Prof 1928-53. b.
Melbourne, 23 Apr 1893.
[15] In particular with the technical
manager Mr H.J. Quinn, and the chief chemist Mr J.S. Blakeney.
[16] J.S. Rogers, "History of the
Scientific Instruments and Optical Panel" (unpublished), to which I am
indebted for much of the information contained in this chapter.
[17] H.C. Little, Factory Chemist,
Aust Window Glass Pty Ltd. Of Sydney; b. Sydney, 15 Nov 1915.
[18] G.H. Grimwade, MA, BSc. Company
director. Of Toorak, Vic; b. Melbourne, 19 Sept 1902.
[19] "The Industrial War Effort of
Australian Consolidated Industries Limited, 1939-45."
[20] Research and Development in
Applied Optics and Optical Glass at the National Bureau of
Standards. Miscellaneous Publications 194 (1949).
[21] R.G. Giovanelli, D.Sc. Teacher
of Physics, Sydney Technical College, to 1940; Research officer,
National Standards Lab, since 1941. Of Sydney; b. Grafton, NSW, 30
April 1915.
[22] Ordinary glass was made in much
larger tanks, rectangular in shape.
[23] C.W. Death. Works Manager ACI
Refractories Pty Ltd 1932-46. Chemist; of Sydney; b. Fordham, Essex,
England. 15 Nov 1901.
[24] Except for the dense barium
crown variety, which was never successfully produced during the war.
[25] A.W. Warren, Chemical engineer
with ACI to 1941, in charge of Optical Glass Annexe 1941-46; Works
Manager ACI Refractories since 1946. b. Goulburn. NSW, 2 Jun 1919.
[26] J.S. Blakeney. Works Chemist,
Aust Glass Manufacturers Pty Ltd, to 1940; Chief Chemist ACI 1940-48,
Works Manager since 1948. Of Sydney; b. Sydney, 26 Feb 1915.
[27] Some glass was imported, but it
was only a small fraction of requirements.
[28] F. Lord. Optical engineer in
Prague 1936-39; Officer in Charge Optical Workshop C'wealth Observatory
1940-45. Of Prague; b. Opava, Czechoslovakia, 16 Sep 1916.
[29] S.J. Elwin, MSc. Lecturer in
manual training, Sydney Teachers' College, till 1939; Lecturer in
Physics at Technical CoDege, then at Teachers' College. Of Sydney; b.
Sunderland, Eng, 11 Feb 1906.
[30] G.F. Dainty. Optical technician,
Barr and Stroud, England, then at Univ of Melbourne. Of Christchurch,
NZ; b. Birmingham, Eng, 20 Oct 1887.
[31] J.J. McNeil, MSc. Physicist with
Munitions Supply Labs (Optics), later with CSIRO. Of Melbourne; b.
Ballarat, Vic, 17 Sept 1916.
[32] V. R. Schaefer. Textile worker
and amateur astronomer. Glass worker and technical offlcer. National
Standards Laboratory, 1941-51. b. 19 Apr 1915. Died Jan 1951.
[33] This was Mr C. Halliday, who had
received his training at the well-known British firm of Barr and
Stroud.
[34] The annexe was designed and
built under the direction of Mr Eric Waterworth. It developed out of
work on the manufacture of prisms and test plates carried out in the
Physics Laboratory of the Univ of Tasmania.
[35] Rogers.
[36] "In this particular," said
Rogers, "U.S. Army drawings are better than those of the War Office
since they give full optical data for each optical component." A
similar comment has been made on British and American drawings for
aero-engines.
[37] "The Industrial War Effort of
Australian Consolidated Industries Limited 1939-45."
[38] L.P. Coombes, DFC; BSc. (Served
RAF first world war.) Senr Scientific Officer. Air Ministry. 1924-38:
Chief, Division of Aeronautics CSIR, 1938-48: Chief Supt of
Aeronautical Research Lab, Dept of SUpply and Development, since 1949.
B. Madras, India, 9 April 1899.