CHAPTER VI.SIGHTS AND FIRE-CONTROL APPARATUS.

At the threshold of the war with Germany we were confronted with the problem of providing on a large scale those instruments of precision with which modern artillerists point their weapons. As mysterious to the average man as the sextant and other instruments which help the navigator to bring his ship unerringly to port over leagues of pathless water, or as those devices with which the surveyor strikes a level through a range of mountains, are the instruments which enable the gunner to drop a heavy projectile exactly on his target without seeing it at all.

The old days of sighting a cannon point-blank at the visible enemy over the open sights on the barrel of the weapon passed with the Civil War. As the power of guns increased and their ranges lengthened, the artillerists began firing at objects actually below the horizon or hidden by intervening obstacles. These conditions necessarily brought in the method of mathematical aim which is known as indirect fire.

In the great war indirect firing was so perfected that within a few seconds after an aviator or an observer in a captive balloon had definitely located an enemy battery, that battery was deluged with an avalanche of high-explosive shell and destroyed, even though the attacking gunners were located several miles away and hills and forests intervened to obscure the target from view. With the aid of correlated maps in the possession of the battery gunners and the aerial observer, a mere whisper of the wireless sufficed to turn a torrent of shell precisely upon the enemy position which had just been discovered. So accurate had indirect artillery fire become that a steel wall of missiles could be laid down a few yards ahead of a body of troops advancing on a broad front, and this wall could be kept moving steadily ahead of the soldiers at a walking pace with few accidents due to inaccurate control of the guns firing the barrage.

The chief difference between the old and the new methods of artillery practice is the degree of precision attained. At the time of the Civil War the artillery was fired relatively blindly, reliance being placed upon the weight of the fire regardless of its accuracy and its effectiveness; but modern artillery has recognized the importance of the well-placed shot and demands instruments that must be marvelsof accuracy, since a slight error in the aiming at modern ranges means a miss and the total loss of the shot. Such uncanny accuracy is made possible by the use of those instruments of precision known as fire-control apparatus. The gunner who is not equipped with proper fire-control instruments can not aim correctly and is placed at a serious disadvantage in the presence of the enemy. These instruments must not only be as exact as a chronometer, but they must be sufficiently rugged to withstand the concussion of close artillery fire.

Equipment classified under "Sights and fire-control apparatus" comprises all devices to direct the fire of offensive weapons and to observe the effect of this fire in order to place it on the target. Included in this list are instruments of a surveying nature which serve to locate the relative position of the target on the field of battle and to determine its range. For this purpose the artillery officer uses aiming circles, azimuth instruments, battery commander telescopes, prismatic compasses, plotting boards, and other instruments. Telescopes and field glasses equipped with measuring scales in them are also employed in making observations.

Instruments of a second group are attached directly to the gun to train it both horizontally and vertically in the directions given by the battery commander. These devices include sights of different types, elevation quadrants, clinometers, and other instruments. The intricate panoramic sight which is used especially in firing at an unseen target is one of the most important instruments of this group.

Still another set of instruments comprises devices such as range deflection boards, deviation boards, and wind indicators which, together with range tables and other tables, assist the battery commander to ascertain the path of the projectile under any condition of range, altitude, air pressure, temperature, and other physical influences. When it is understood that the projectile fired by such a weapon as the German long-range gun which bombarded Paris at a distance of 70 miles mounts so high into the air that it passes into the highly rarified layers of the air envelope surrounding the earth and thus into entirely different conditions of air pressure, it can be realized how abstruse these range calculations are and how many factors must be taken into account. The fire-control equipment enables the artilleryman to make these computations quickly.

In addition to the above items many auxiliary devices are needed by the Artillery, notable among these being the self-luminous aiming posts and other arrangements which enable the gunners to maintain accuracy of fire at night. This whole elaborate set of instruments is supplied to the field and railway artillery—the big guns—and in part to trench-mortar batteries and even to machine guns, which in the latter months of the war were used in indirect firing.

Still another group of pointing instruments is used by antiaircraft guns against hostile aircraft to ascertain their altitude, their speed, and their future location in order that projectiles fired by the antiaircraft guns may hit these high and rapidly moving targets. Sights are also used on the airplanes themselves to aid the pilot and the observer in the dropping of bombs and in gunfire against enemy planes or targets. One of these sights corrects automatically for the speed and direction of the airplane.

Fuse setters, which enable the gunner to time the fuse in the shell so that the projectile moving with enormous speed explodes at precisely the desired point, were required in large numbers.

The responsibility for the design, procurement, production, inspection, and supply of the above equipment to the American Expeditionary Forces was lodged in the Ordnance Department. The effectiveness of the artillery on the field of battle depended directly on the fire-control equipment furnished by this bureau.

The optical industry in this country before the war was in the hands of a few firms. Several of these were under German influence, and one firm was directly affiliated with the Carl Zeiss Works, of Jena, Germany; the workmen were largely Germans or of German origin; the kinds and design of apparatus produced were for the most part essentially European in character; optical glass was procured entirely from abroad and chiefly from Germany.

It was easier and cheaper for manufacturers to order glass from abroad than to develop its manufacture in this country. Educational and research institutions obtained a large part of their equipment from Germany and offered no special inducement for American manufacturers to provide such apparatus. Duty-free importation favored and encouraged this dependence on Germany for scientific apparatus.

With our entrance in the war the European sources of supply for optical glass and optical instruments were cut off abruptly and we were brought face to face with the problem of furnishing these items to the Army and Navy for use in the field. Prior to 1917 only three private manufacturers in the United States had built fire-control apparatus in any quantity for the Government. The Bausch & Lomb Optical Co., Rochester, N. Y., had made range finders and field glasses for the Artillery and Infantry, and gun sights, range finders, and spy glasses and field glasses for the Navy; the Keuffel & Esser Co., Hoboken, N. J., had produced some fire-control equipment for the Navy; the Warner & Swasey Co., Cleveland, Ohio, with J. A. Brashear, Pittsburgh, Pa., had furnished depression-position finders, azimuth instruments, and telescopic musket sights to the Army. The only other source of supply in this country had been the Frankford Arsenal.

Prior to 1917 the largest order for fire-control equipment which our Army had ever placed in a single year amounted to $1,202,000. The total orders for such instruments placed by the Ordnance Department alone during the 19 months of war exceeded $50,000,000, while the total orders for fire-control apparatus placed by the Army and Navy exceeded $100,000,000.

To meet the situation, existing facilities had to be increased, new facilities developed, and other, allied, industries converted to the production of fire-control material.

Quantity production had to be secured through the assembling of standardized parts of instruments which heretofore had either never been built in this country or only in a small, experimental way. A large part of the work had of necessity to be done by machines operated by relatively unskilled labor. The manufacturing tolerances had to be nicely adjusted between the different parts of each instrument, so that wherever less precise work would answer the purpose the production methods were arranged accordingly. Only by a careful coordination of design, factory operations, and field performance could quantity production of the desired quality be obtained in a short time. Speed of production meant everything if our troops in the field were to be equipped with the necessary fire-control apparatus and thus enabled to meet the enemy on even approximately equal terms.

To accomplish this object a competent personnel within the Army had to be organized and developed; the Army requirements had to be carefully scrutinized and coordinated with reference to relative urgency; manufacturers had to be encouraged to undertake new tasks and to be impressed with the necessity for whole-hearted cooperation and with the importance of their part in the war; raw materials had to be secured and their transportation assured. These and other factors were faced and overcome.

Although American fire-control instruments did not reach the front in as large numbers as were wanted, great quantities were under way, and we had attained in the manufacturing program a basic stage of progress which would have cared for all of our needs in the spring and summer of 1919. Incidentally there has been developed in this country a manufacturing capacity for precision optical and instrument work, which, if desired, will render us independent of foreign markets. At the present time there exists in this country a trained personnel and adequate organization for the production of precision optical instruments greatly in excess of the needs of the country. One of the problems which we now have to consider is the conversion of this development brought about by war-time conditions into channels of peace-time activity.

At the present time American manufacturers are in a position to make instruments of precision equal to the best European product, and the industry will continue, provided there is an adequate market for its product. Such a market will exist if the universities and commercial laboratories of the country will obtain scientific apparatus from American manufacturers rather than import it from abroad as has heretofore been the custom.

In April, 1917, the most serious problem in the situation was the manufacture of optical glass. Prior to 1914 practically all of the optical glass used in the United States had been imported from abroad; manufacturers followed the line of least resistance and preferred to procure certain commodities, such as optical glass, chemical dyes, and other materials difficult to produce, direct from Europe rather than to undertake their manufacture here. The war stopped this source of supply abruptly, and in 1915 experiments on the making of optical glass were under way at five different plants—the Bausch & Lomb Optical Co. at Rochester N. Y.; the Bureau of Standards at Pittsburgh, Pa.; the Keuffel & Esser Co. at Hoboken, N. J.; the Pittsburgh Plate Glass Co. at Charleroi, Pa.; the Spencer Lens Co. at Hamburg, Buffalo, N. Y.

By April, 1917, the situation had become acute; some optical glass of fair quality had been produced, but nowhere had its manufacture been placed on an assured basis. The glass-making processes were not adequately known. Without optical glass fire-control instruments could not be produced; optical glass is a thing of high precision and in its manufacture accurate control is required throughout the factory processes. In this emergency the Government appealed to the Geophysical Laboratory of the Carnegie Institution of Washington for assistance.

This laboratory had been engaged for many years in the study of solutions, such as that of optical glass, at high temperatures and had a corps of scientists trained along the lines essential to the successful production of optical glass. It was the only organization in the country with a personnel adequate and competent to undertake a manufacturing problem of this character and magnitude. Accordingly, in April, 1917, a group of its scientists was placed at the Bausch & Lomb Optical Co. and given virtual charge of the plant; its men were assigned to the different factory operations and made responsible for them. By November, 1917, the manufacturing processes at this plant had been mastered and large quantities of optical glass of good quality were being produced. In December, 1917, the work was extended, men from the Geophysical Laboratory taking practical charge of the plants of the Spencer Lens Co. and of the Pittsburgh Plate Glass Co.

The cost to the Geophysical Laboratory of contributing to the Government the solution of the optical glass problem amounted to about $200,000, but the results attained surely more than justified these expenditures. These results could not have been attained, however, without the hearty cooperation of the manufacturers and of the Army and Navy, which assisted in the procurement and transportation of the raw materials. An ordnance officer was in charge of the Rochester party from the Geophysical Laboratory and was responsible for much of the pioneer development work accomplished there. It was at this plant, that of the Bausch & Lomb Optical Co. at Rochester, that the methods of manufacture were first developed and placed on a production basis. The Bureau of Standards aided in the development of a chemically and thermally resistant crucible in which to melt optical glass; also in the testing of optical glass, and especially in the testing of optical instruments. The Geological Survey aided in locating sources of raw materials, such as sand of adequate chemical purity.

By February, 1918, the supply of optical glass was assured; but the manufacture of optical instruments was so seriously behind schedule that a military optical glass and instrument section was formed in the War Industries Board and took charge of the entire optical instrument industry of the country. Through the efforts of its chief, Mr. George E. Chatillon, of New York, the entire industry was coordinated. By September, 1918, the production of fire-control instruments in sufficient quantities to meet the requirements of both the Army and Navy during 1919 was believed to be assured.

To the accomplishment of this result the Ordnance Department contributed most effectively. The information and long experience of Frankford Arsenal in instrument manufacture and in the work of precision optics were placed at the service of contractors; trained officers of the Ordnance Department were stationed at the different factories; in many factories these officers rendered valuable aid in devising and developing proper and adequate factory operations, in establishing production on a satisfactory basis, in securing the proper inflow of raw materials, in devising testing fixtures, in establishing proper manufacturing tolerances, and in testing the performance of the assembled instruments. Schools for operatives in precision optics were established at Frankford Arsenal, Philadelphia, Pa., at Rochester, N. Y., and at Mount Wilson Observatory, Pasadena, Cal. To many contractors financial aid had to be extended. The fire-control program required, in short, all the available talent and resources of the country to carry it to a successful finish.

The general procedure adopted by the Ordnance Department was to assign the more difficult instruments to manufacturers who had had experience along similar lines. To others, who had producedarticles allied only in a distant way to fire-control instruments, less intricate types of instruments were awarded. In certain instances the optical elements were produced by one firm, the mechanical parts by another, the final assembly of the instrument being then accomplished by the latter.

Because our Army had adopted a number of French guns for reproduction here, it became necessary to build sights for these weapons according to the French designs. This gave us much trouble, not only because of the delay in securing samples and drawings from France, but because of the difficulties in producing articles from these French drawings by American methods and with American workmen.

The most intricate of these French sights was the Schneider quadrant sight. It was used with the French 155-millimeter gun, the 155-millimeter howitzer, and the 240-millimeter howitzer. The structure of this sight was highly complicated, and extreme accuracy was required at every stage of production. These sights were put into production by the Emerson Engineering Co. of Philadelphia, the Raymond Engineering Co. of New York, and by Slocum, Avram & Slocum of New York.

The design of this sight was received from France early in 1918, yet it was the 1st of November—10 days before the armistice was signed—when the first Schneider sight was delivered to the Army; but at all times the progress made was as rapid as could be expected. A total of 7,000 Schneider quadrant sights was ordered, which meant a year's work for 1,000 men. Of this order 3,500 sights were to be manufactured by the Schneider Co. in France and the rest by the three firms in this country. On November 11 the American factories had delivered 74 sights and since that time over 560 have been completed.

The amount of labor involved in the case of Schneider quadrant sights is shown by the fact that while the raw material for it cost about $25, the finished sight is worth about $600. In order to expedite production the Government extended financial assistance to some of the factories to aid in the procurement and installation of additional equipment. On November 11 the number of these sights completed was short of requirements for installation on completed carriages by about 400, but the rate of progress which had been attained in production would have overtaken the output of gun carriages by January 1, 1919.

Another difficult task was the construction of telescopic sights for the French 37-millimeter guns, the "Infantry cannon" which we adopted for reproduction in this country. Here again we encountered the same difficulty of adapting French plans to our methods. The original contract was placed with a firm which had had no experience with optical instruments of precision, but no other company was available for the work. When by May, 1918, this concern had produced only a few sights the contract was taken from it and placed with a subcontractor, the Central Scientific Co., of Chicago, who had been building mechanical parts for the sights. In this plant the complete force had to be educated in the art before any production could begin. When the armistice was signed the gun factories had produced 884 of the 37-millimeter guns, but only 142 telescopic sights had been completed. The rate of production of these sights by the Central Scientific Co. was such, however, that the shortage would have ceased to exist shortly after January 1, 1919.

The French design for the telescopic sight for the 37-millimeter gun used on the tanks was also adopted by the Army. Here again difficulty was experienced in manufacture, but excellent progress was made especially by one firm (Burke & James of Chicago, Ill.), and the output in adequate quantities was assured for 1919. The French collimator sight for the 75-millimeter gun presented difficulties to the manufacturer, especially in the optical parts. These were, however, overcome by the Globe Optical Co., who furnished the optics to the Electric Auto-Lite Corporation and to the Standard Thermometer Co. of Boston, with the result that at the time of the signing of the armistice the production of these sights was progressing well.

Periscopes from 20 inches to nearly 20 feet in length were produced in quantity. These periscopes enabled the men in the front-line trenches to look over the top with comparative safety. The long periscopes were used in deep-shelter trenches and bomb proofs. The production of the short-base periscopes and also of the battery commanders' periscopes by the Wollensak Optical Co., Rochester, N. Y., and of the 3-meter and 6-meter periscope by the Andrew J. Lloyd Co. of Boston, Mass., was progressing at such a rate that the needs of the Army for 1919 would be met on time.

At the outbreak of the war the policy followed by the Ordnance Department was to place orders for standard fire-control apparatus, such as range finders of different base lengths, battery commander telescopes, aiming circles, panoramic sights, musket sights, and prismatic compasses with firms of established reputation and experience. The result was that when requests from the Army in France came for instruments of new design, new sources of manufacture had to be sought out and these organizations educated in the methods of precision optics. Such a procedure necessarily caused delay, but it was the only course of action left. Wherever possible part of the total contract was awarded to an experienced manufacturer, so that some production was assured.

PANORAMIC SIGHT.

BATTERY COMMANDER'S TELESCOPE.

BATTERY COMMANDER'S PERISCOPE.

AIMING CIRCLE.

BRACKET FUSE SETTER, MODEL OF 1916.

RANGE FINDER.

FRENCH QUADRANT SIGHT WITH AMERICAN PANORAMIC SIGHT.

SIGHT FOR 75-MILLIMETER FIELD GUN.

The records show that the experienced manufacturers overcame the difficulties encountered and had obtained in general a rate of output which was satisfactory at the time of the signing of the armistice. Thus the Bausch & Lomb Optical Co. had delivered large numbers of range finders of base lengths of 80 centimeters, 1 meter and 15 feet, and battery commanders' telescopes; Keuffel & Esser had made many prismatic compasses and a few range finders; the Spencer Lens Co. had produced aiming circles in quantity; the Warner & Swasey Co., with J. A. Brashear of Pittsburgh, had furnished large numbers of the valuable panoramic sights with which much of the artillery fire is directed. Much credit is due the above organizations for the efficient manner in which they placed the manufacture of these items on a high-speed production basis. Frankford Arsenal proved to be a most reliable source of supply for battery commander telescopes, panoramic sights, azimuth instruments for 3-inch telescopes, plotting boards, and other ordnance fire-control instruments.

The manufacture of many other types of instruments was undertaken in this country. Among these the French sitogoniometer, a device which assists the battery commander in obtaining data for the direction of fire, was successfully produced by the Martin-Copeland Co. of Providence, R. I.; quadrant sights for the 37-millimeter gun by the Scientific Materials Co. of Pittsburgh; lensatic compasses and Brunton compasses were furnished by Wm. Ainsworth & Sons of Denver, Colo.; prismatic compasses by the Sperry Gyroscope Co. of Brooklyn, N. Y.; telescopes for sights on antiaircraft carriages by the Kollmorgen Optical Corporation of Brooklyn; altimeters, gunners' quadrants, elevation quadrants, and aiming stakes by the J. H. Deagan Co. of Chicago, Ill.; panoramic telescopes and fuse setters by the Recording & Computing Machines Co. of Dayton, Ohio; battery commander telescopes by Arthur Brock of Philadelphia; tripods for fire-control instruments by the National Cash Register Co. of Dayton, Ohio. Optics for different sights were furnished by the American Optical Co. of Southbridge, Mass., and by the Mount Wilson Observatory of Pasadena, Calif. These and other organizations entered into the task and devoted their energy to the production of equipment desired by the Government.

At no time during the fighting did our artillery units have a sufficient supply of fire-control instruments. This was due to the fact that we were not able to secure in Europe the amount of this equipment required to take care of our needs while our own industry was being developed.

With almost a total lack of optical glass in this country, with an equal lack of factories and workmen familiar with military optical instrument-making, we were suddenly called upon to produce about200 different types of instruments in large quantities. These included many new designs of fire-control apparatus made necessary by new artillery developments both among the allies and in our own factories, by the adoption of trench warfare in place of open warfare, by the development of weapons for use against aircraft, by the extension of indirect fire-control methods to weapons which formerly had been fired by direct sighting, and by the use of railway and seacoast artillery.

While we did not solve all the difficulties in this development, we had met and conquered the worst of them, and we were making such great strides in production when the war ended that all the requirements of the Army would have been met early in 1919. It has been a source of inspiration to witness the high sense of patriotic duty and cooperation shown by the manufacturers which made possible the remarkable expansion of the optical glass and instrument industry in the United States during the period of the war.

The following table shows the principal items of sights and fire-control apparatus, the firms that did the work, the quantity of the various kinds of instruments ordered, and the deliveries made up to November 11, 1918, and to February 20, 1919:

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