During the spring and summer of 1917 two marked tendencies were to be observed in the fighting in France. One of these was the greatly increased use by both sides of poisonous gases and chemicals, frightful in their effect; the other the almost complete censorship that hid the knowledge of this tendency not only from the people of Europe but particularly from those of the newest belligerent, America. The French and British Governments, who then controlled all news from the front, feared, and perhaps with reason, that if the picture of gas warfare, as it was then developing, should be placed before the American people, it would result in an unreasonable dread of gases on the part of the American Nation and its soldiers.

One year later, with tens of thousands of American troops facing the Germans, there was almost no censorship upon the details of fighting with chemicals. The mysterious gases of 1917 were then known to almost every reading individual in the civilized world. The once secret formulas were published in the technical journals. Non-censored photographs of defensive equipment were freely published, and masks and other paraphernalia were exhibited for the public interest. Except for secret plans for the future and the various surprises being prepared by one or more of the belligerents, the whole subject of chemical warfare had become an open book.

What occasioned this change in policy on the part of governing authorities? The reason was that the American troops brought with them to France the best and most protective gas masks the world had seen; and they brought these with them by the millions. Starting a mask-production effort in May, 1917, America turned out a total of 5,250,000 gas masks before the armistice was signed, and sent more than 4,000,000 of them overseas. As to the quality of these masks, it is only necessary to say that they gave twenty times the protection afforded by the best German gas masks. In other words, we protected our soldiers against the poisons which Germany had brought into warfare, and protected them completely. No American soldier was ever gassed due to the failure of an American gas mask, and such gas casualties as did occur were due to the fact that the masks were not quickly enough utilized when gas was thrown over, or because the soldier was unaware of the presence of gas. With such protection there was no longer reason to fear that the frightfulness of chemical warfare would reduce American morale.

The production of gas masks was one of the most picturesque and successful phases of our entire war preparation. It engaged the attention of some of the principal chemical engineers of the country, and millions of men, women, and children in the United States contributed something to the success of the undertaking, if only to obey the "Eat More Coconut" slogan or to save peach stones for the benefit of the production of the charcoal essential to efficient gas masks.

The problem of making masks in such quantity and under such supreme demands for perfection was one which might well stagger manufacturers accustomed to large-scale operations. We started in with practically no knowledge whatsoever of the fundamental principles of a perfect mask. Yet the apparatus was as difficult to build as a rifle. It must, perforce, be made of perishable materials, and this fact brought the question of durability to the fore at the very start. It was evident that no chemical substances known in our past commercial life would give protection against the new poisons which had been developed in Europe. With the exception of phosgene and chlorine, the various war gases which had been brought out prior to our entrance in the struggle were completely unknown in our trade or commerce and had existed only in our experimental laboratories. Then it was discovered that as these toxins increased in power they could penetrate the ordinary fabrics known in commerce, and this necessitated the creation of new types of materials to be used in the masks. Finally the increasing use of gases forced the soldiers to wear their masks for much longer periods than had been necessary at the beginning of gas warfare; so that the problem of comfort became one of great importance. All of these basic considerations indicate to some extent the difficulty of the undertaking.

The chlorine, which floated in a pale greenish-yellow cloud down upon the defenseless Canadian troops at Ypres, with such terrible effect upon the men, was, as has been said, the first gas used. Chlorine, though easy to obtain, the principal source of supply being common table salt, was, from the standpoint of strategy, far from being the ideal gas of warfare. Troops could be quickly and easily protected from it. But even as it was, only lack of faith in their new weapon prevented the Germans from winning the war with it then and there. Had they brought into the fighting a sufficient supply of this chlorine, they might have gassed their way to Paris in short order. In fact, they brought to the line an almost negligible supply and they themselves were insufficiently protected to go through their own gas and follow up the attack. By the time they were able to renew gas warfare the French and British had equipped themselves with masks which were sufficient to protect men against chlorine.

Thereafter the tendency was toward new and strange gases which were heavy in weight and highly toxic in their physiological action. This development led to new, slightly volatile liquids, the so-called mustard gas being the best example. Mustard gas (properly called dichlorethyl sulphide) is similar to lubricating oil in many of its physical characteristics but smells like ordinary mustard. Ground soaked with the mustard gas remains impregnated for days, the vapor rising continually.

A perfect mask is one which will remove completely every trace of gas or poisonous vapor before the air can reach the eyes, nose, or mouth of the soldier.

The first masks adopted by the allies were simply gauze pads saturated with neutralizing chemicals. These became unsuitable as soon as new varieties of powerful poisons were brought out. The mask development thereafter progressed to the box respirator type. This consisted of a mask or helmet connected to a box filled with absorbing and neutralizing chemicals which purified the air for the mask wearer. This was the type of respirator in use to the end of the fighting.

It is quite clear to us now that only such a mask could be efficient in chemical warfare, but in the early part of 1917 the matter was not clear either to us or to the allies. The first requisitions from the A. E. F. called for masks of two types, each soldier to be supplied with one of each. The reserve mask was to be of the gauze type and the regular mask of the box respirator type, affording protection from the more powerful poisons that were then just coming into use. We wasted considerable energy at the beginning in our attempt to produce both types. Eventually, however, when we were just ready to start manufacturing the gauze-type mask, orders came to abandon the effort, since it was even then apparent that our soldiers must be prepared at all times to withstand all gases.

The box respirator equipment, the general principle of which was finally adopted by all the nations at war, fell into two classes. In a single-protection mask the wearer breathed air from inside of the face piece, so that any leakage around the edges of the face piece would result in a casualty when the wearer was in a strong concentration of gas. The other sort, known as the double-protection mask, consisted of a gas-tight face piece, similar to that of the single-protection mask. In this type, to guard against any possible leakage around the edges between the mask and the wearer's skin, the breathing system was sealed away from the air inside the face piece by means of a rubber mouthpiece and a nose clip, the wearer inhaling through the mouthpiece.

The United States and English double-protection masks consisted of 11 principal parts as follows:

1. A knapsack slung from the shoulder or neck. This contained the canister and a pocket for storing away the mask when not in use.

2. A metal canister in which was contained the absorptive neutralizing chemicals.

3. A flexible hose reaching from the canister to the face piece.

4. A flutter, or exhalation, valve, which opened when the wearer exhaled his breath and closed when he inhaled, thus bringing the inhalation through the canister but allowing the exhalation from the lungs to pass out without polluting the chemicals of the canister.

5. The face piece, or hood, fitting snugly around the edges and covering the eyes, cheeks, lower forehead, nose, mouth, and chin.

6. The eyepieces, or lenses, through which vision was maintained.

7. An elastic harness for the head, to hold the face piece in place.

8. A body cord to tie around the chest and hold the knapsack firmly, so that the mask could be seized in both hands and pulled out of the knapsack.

9. A metal flange connection or angle tube which carried the hose through the face piece to the mouthpiece.

10. A rubber mouthpiece through which the wearer breathed and which helped to hold the mask in place.

11. A wire nose spring and rubber nose pad to hold the nostrils shut and force breathing through the mouth.

The first order for gas masks was issued on May 16, 1917, when the Chief of Staff asked the Surgeon General to supply 1,100,000 masks before June 30, 1918, or within about one year. Meanwhile 25,000 masks were needed at once in order to equip Gen. Pershing's first division, then about to sail overseas. There was but one man in the Army who knew anything at all about the subject and who could even attempt to produce this quantity in three weeks. This was Maj. (later colonel) L. P. Williamson, of the Surgeon General's Department, who had been spending some months at the Army War College at Washington studying as a side issue such papers on gas warfare as came from abroad. It was due to his knowledge and the volunteer staff of the Bureau of Mines that we were able to begin the actual manufacture of masks within a few days after the requirements were fixed, and actually to turn out 25,000 masks in but little more than three weeks' time.

Col. Williamson's first step was to consult with Dr. Van. H. Manning, the Director of the Bureau of Mines, and with his assistant, Mr. G. A. Burrell. Since February, 1917, the Bureau of Mines had been experimenting with gas masks and had built up a corps of scientists for this work. Within this organization was Mr. Bradley Dewey, a chemical engineer, who, though then director of the research laboratory of the American Sheet & Tin Plate Co., of Pittsburgh, had been loaned to the Bureau of Mines. To Mr. Dewey was turned over the job of directing the production of the first 25,000 masks for the American troops then sailing.

To produce 25,000 gas masks in three weeks meant to compress England's two years of experience into 21 days. The military authorities of this country at that time could plead entire ignorance of the qualifications of an efficient gas mask. The prevailing idea seemed to be that you could go out into the market and buy them by the hundreds of thousands, as you might buy Halloween masks. But this was not any ordinary poison which we were to fight. These powerful chemicals attacked the human tissues as would acid. As the result of the effort, we did supply the first division going overseas in July. However, the masks were inferior to the British and were quickly replaced in France by British equipment. It was not until the following January that we developed an apparatus which we regarded as satisfactory to undergo the supreme test of battle.

To indicate some of the difficulties overcome between May and December, 1917, there are here set forth some of the features of an effective mask.

In the first place, the face piece must fit perfectly; it must not leak gas around the edges. It must fit into the hollows of the temples and must give the jaws a free space in which to work, and yet not slip back and press against one's Adam's apple. The pressure of the mask on the forehead must come above the supraorbital nerves which are just above the eyebrows, or else intense headaches will result from a few moments' wear. Moreover, to fit all faces and heads, several graduated sizes of masks are required. We first attained the gas-tight fit with a padded band around the edge of a flexible rubber-cloth face piece. Later we developed a thicker, stiffer face piece, but maintained a gas-tight fit by the elasticity of the face piece and the head harness.

Then the material of the face piece must be gas-tight in itself. At first we manufactured a fabric made by spreading rubber on cotton sailcloth; and, after testing it, we found that the smallest molecule known, that of hydrogen, would not pass through it in large amounts. This seemed to be a suitable fabric, until tested by the newer gases. Then we found that some of these gases were soluble in rubber compounds and could dissolve their way through thin rubber so quickly that the face piece cloth offered practically no protection at all. Another difficulty with the rubber fabric was that it was likely to absorb and hold certain of the poisons, so that a man might be gassed by the mask itself. The rubber companies, principally at Akron, Ohio, experimented continually until they discovered a coating that would not only withstand gas concentrations for a sufficient time, but would also aerate promptly and lose as much gas as it had absorbed.

The eyepieces or lenses offered another problem. Celluloid is strong but it is not so transparent as glass. It ignites easily and is easily scratched. Glass is ideal in transparency and will not burn, but is fragile. It was evident that we must provide eyepieces which would not break easily, since even so slight an accident as the breaking of a lens might cost a soldier his life by admitting concentrated gas to the mask. A material known as triplex glass had been experimentally made. This consisted of a thin celluloid strip sandwiched between two layers of glass, all three welded together. This glass would not splinter, and even if cracked or broken, would still be gas-tight. However, this had never been made in quantity and it was necessary to work out many kinks and to start a large plant to provide the necessary millions of lenses.

Then there was also to be overcome the tendency of the eyepieces to dim, particularly in cold weather, as the wearer breathed moist breath into the mask. The answer to this problem was a soapy compound which put a slippery surface on the glass and avoided the droplets of mist. The first masks were also equipped with deep plaits so that the wearer could wipe off the lens with the interior of the face-piece itself, though the final development (the invention of a Frenchman by the name of Tissot) was to bring the cold air into the mask so that it flowed directly against the lenses and evaporated any condensed moisture. This kept them clear under all ordinary circumstances.

It was evident that the metal tube passing through the face piece must not contain pinholes and must be able to stand rough handling without pulling loose. The harness must maintain a gas-tight connection between the wearer's face and the face piece, but not at the cost of pain or chafing of the face or head. The flutter valve must fit with absolute tightness and must work perfectly and instantaneously at all times.

The flexible hose leading from the canister to the face piece must be strong and without flaws or leaks, and yet flexible in the extreme. A stiff hose would be likely to swing and displace the face piece whenever the wearer moved. The mouthpiece must be comfortable and must be built along lines to prevent irritation to the gums or lips, yet it must be reinforced so that in his excitement the soldier can not bite down and shut off his air supply.

The canister must withstand corrosion and must be gas-tight. Smooth sided canisters can not be used, for the gas would slip up the sides without coming in contact with much of the chemical filling. The sides of the canisters were, therefore, ribbed so that the charcoal and other ingredients working into these ribs baffled the gas and threw it out into the body of the chemicals. The canister, moreover, must be equipped with a perfectly working check valve which will stop exhalation through the canister and force the air to pass out through the flutter valve.

The web sling of the knapsack must not curl and chafe the neck or shoulders of the wearer. The knapsack must be waterproof and must have easily and quickly workable fastenings.

The canisters were filled with charcoal and with cement granules. These were crushed into carefully sized small bits about the size of a pinhead and packed in layers in the canisters. The air could pass through them easily and the particles of both substances absorbed gas. The chief quality requirements for the carbon and the cement were that they must have long life and great activity.

Of the canister ingredients the charcoal offered the more difficult technical problem. It had long been known that charcoal was highly absorptive of certain gases, but except in rare instances no thorough study had ever been made of the subject. It was evident, however, that the more charcoal or carbon which could be packed into the canister and still allow the free passage of air the greater the amount of gas that would be absorbed. Consequently a search was made for carbon existing in the natural state in the most compact form. This search is described later.

Each canister also contained concrete granules in a definite proportion to the carbon pieces. These granules were made of cement mixed with strong alkalis and oxidizing agents to digest the poisons as they passed through the canister.

It will be seen that the manufacture of good gas masks was a highly technical undertaking, one calling for the best talents of eminent men of science. The mask was not something that could be improvised on the spur of the moment, but each part of it must be worked out after the most painstaking research. The Gas Defense Division of the Chemical Warfare Service never at any time approved a type of mask which its own officers or men did not themselves wear in the most deadly concentrations of gas.

To get back to the chronological order of development, on May 21, 1917, the making of the first 25,000 masks was started with frantic haste; though, as it developed later, there was no need for such an effort, since there were available in England and France plenty of masks for the first American troops. Working to produce in the shortest possible time some sort of protection for the first overseas division, the officers in charge were forced to adopt methods which, had they been followed throughout the manufacturing program, would have been extremely costly. There was no time then to stop and study the problem either here or abroad. Before the end of June 20,088 masks had been started overseas, and 5,000 more were ready a little later. The most that can be said for this effort was that it gave our officers the experience which was the groundwork of the solid development later on.

The production of these first 25,000 masks called upon the services of various manufacturers. The assembling of the masks was conducted by the American Can Co., at Brooklyn, N. Y. The B. F. Goodrich Co., of Akron, manufactured the face pieces with the eyepieces inserted, also the connecting hose, the check valve of the canister, the flutter valve, and the rubber mouthpiece. The American Can Co. produced the canisters. The Day Chemical Co., of Westline, Pa., gave the charcoal its first burning. The Ward Baking Co., of Brooklyn, patriotically baked the charcoal—to activate it—in their bread ovens free of charge. The General Chemical Co., of New York, supplied the soda-lime granules. The Doehler Die Casting Co., of Brooklyn, manufactured the angle tubes. The Simmons Hardware Co., of St. Louis, produced the waterproof knapsacks. The Seaver Howland Press, of Boston, printed the cards of instructions that went with the mask outfit; and the Beetle & MacLean Manufacturing Co., of Boston, printed the record tags.

Though Maj. (now colonel) Williamson was formally in charge of this emergency work, he requisitioned the masks from the Bureau of Mines, which took entire charge of the first contract. Following this, on August 31, 1917, the Gas Defense Service of the Surgeon General's Department was established by official order, and Mr. Dewey, who had been working as a volunteer in the Bureau of Mines, was commissioned major and put in charge.

The next step was to prepare for the permanent development and manufacture of gas masks. Contracts were let for the manufacture of 320,000 component parts of masks as we then knew them, and a price was fixed for the assembling of the entire original requirement of 1,100,000 masks. The assembling contract went to the Hero Manufacturing Co., of Philadelphia, which remained until the end of the war the sole private contractor assembling our gas masks.

The spirit of cooperation and desire to serve the Government was evident from the start. The B. F. Goodrich Co. had been the only producers of the rubber parts of the first 25,000 masks. In this original contract it had gained valuable technical and cost knowledge; but in order that the Government might not be limited to one source of supply for such parts, the Goodrich Co. voluntarily imparted to the Goodyear Tire & Rubber Co. and to the United States Rubber Co. the information that would enable them to bid intelligently for portions of the work. This was a distinct departure from the usual practice in competitive industry.

All during the fall of 1917 and early winter of 1917-18 the development of the mask continued, the Government experts working hand in hand with private contractors. Because of the newness of this sort of manufacture and because of the wide variety of unusual articles required, entailing in some instances the actual creation of hitherto unknown commodities, the Government at all times was required to act as the procurer of raw materials for the masks. In this period of development America designed her own typical mask—a gradual evolution, but one which, though based on the British design, arrived at a perfection which had been unknown in warfare before.

The triplex glass used in the eyepieces was a patented commodity produced only in one small factory in Philadelphia. It was necessary to expand the facilities for the production of this necessary material. Meanwhile some of the men engaged in the work had improved the eyepiece by providing it with an aluminum mounting. But this very improvement brought embarrassment to the work, since the Akron rubber contracts had provided for eyepieces inserted in the fabric itself, and to apply the aluminum frame brought about a radical change in the manufacturing methods at the rubber factories.

There were also many other problems that had to be solved before our authorities were satisfied to go ahead in quantity production. There was the matter of rubberizing the face-piece fabric, for instance. Two methods of rubberizing cloth were in use. The first method was to roll out a thin sheet of rubber and then press it into the cloth fabric by running the whole thing under heavy rollers. This was known as the calender method. The other method, called the spreader method, was more intricate. In this process the sailcloth, tightly stretched, was carried around a roller. Above the roller a few thousandths of an inch was a knife blade extending from edge to edge. The rubber compound in liquid form was then fed upon the roller in such manner that a thin film of it pressed under the knife blade and upon the cloth on the roller. The rubberizing method finally adopted was a combination of the calender and spreader methods. The rubber was applied green to the cloth. The curing process thereafter was highly important. If the curing process were too short, the rubber would be sticky and would pull off the sailcloth too easily. If the rubber were over-cured, it would crack and split.

Nothing short of absolute perfection in every part would do, since the slightest imperfection anywhere was likely to cost a man his life. Consequently we installed at the various producing plants not only 100 per cent inspection, but we constructed laboratories for putting the materials through the most elaborate and exhaustive sorts of control tests, and then reinspected the parts at the assembly plants, both before and after the assembly.

All the rubber used was continually sampled and analyzed in the laboratories. The tensile strengths of all fabrics were determined by standard destructive tests. We also tested the adhesion of the rubber coating by standard chemical methods and worked out flexibility tests for the breathing tube.

After all of the factory inspection and material-control tests, the masks themselves were sampled and worn in highly toxic atmospheres. In this work thousands of our masks were worn by the officers and men of the Gas Defense Division in concentrated atmospheres of the most deadly gases. For such work we constructed testing rooms whose atmosphere could be completely exhausted and changed in 90 seconds. The efficiency of canisters was tested either by the lungs of the inspectors or by mechanical breathing into telltale solutions.

The story of the carbon (charcoal) which went into the American canister is one of the most interesting phases of the whole undertaking. Investigations carried on by the research staff of the National Carbon Co., aided by a clue from the University of Chicago, led to the selection of coconut shell as a raw material. Any carbon absorbs a definite number of times its weight of gas. Therefore the densest carbons will be most efficient, volume for volume, as gas absorbers in a given space. Coconut shells and other nut shells were found to be the most compact form in which carbon exists in nature in commercially practicable quantities, being considerably superior in this respect to anthracite coal and to such woods as ironwood and mahogany. Another essential for charcoal used in the canisters was that it must be so hard that it would not crumble easily and produce dust that would clog up the air passages and prevent easy breathing through the canister. Coconut shell fulfilled both of these conditions better than any other known material.

Further study by the National Carbon Co., backed up by wonderful large-scale development work, paid for and carried out by the National Electric Lamp Association under the direction of their Mr. F. N. Dorsey (who later became Col. Dorsey and chief of the Development Division of the Chemical Warfare Service), gave us the details of a new process for treating the charcoal to make it absorptive. After the original burning of the nut shells, or other carbon materials, the resulting carbon was given a second highly specialized heat treatment, and this activated it until it had a powerful affinity for gas. Such carbon, made from nutshell material, would absorb 150 times its own volume of chlorpicrin, one of the most deadly of the war gases, the action being approximately instantaneous.

It must not be supposed, however, that investigation of carbons stopped with these experiments. In the search for the ideal carbon we experimented with almost every hard vegetable substance known. Literally, hundreds of kinds of carbon were tested. Next to coconut shells, the fruit pits, several common varieties of nuts abundant in the United States, and several tropical nuts, were found to make the best carbon. Pecan nuts, and all woods ranging in hardness from ironwood down to ordinary pine and fir, were found to be in the second class of efficiency. Among other substances tested were almonds, Arabian acorns, grape seeds, Brazil-nut husks, balsa, osage oranges, Chinese velvet beans, synthetic carbons, cocoa bean shells, coffee grounds, flint corn, corn cobs, cottonseed husks, peanut shells and oil shale. While many of these substances might have been used in an emergency, none of them would produce carbon as efficient, volume for volume, as that of the coconut shells and other hard nuts.

Some idea of the scale of the American mask production may be seen in our requirements for coconut shells. In our survey of raw materials we included the entire coconut resources of the world. Such figures were relatively easy to obtain because the copra, or dried coconut meat, industry is an important one, particularly in southern Asia and the South Sea Islands of the Pacific. Ceylon was the greatest single source of coconuts, 2,300,000,000 nuts being gathered there annually. British India was next with 1,500,000,000 nuts. Our own Philippine Islands were third, with an annual production of 900,000,000 nuts. Then followed in order the Dutch East Indies, British Malaya, French Indo-China, Siam, and the Pacific archipelagos, the total production of the Orient being 7,450,200,000 nuts annually. This was a supply that would provide 4,000 tons of coconut shells every day. The total production of coconuts in Central America, the West Indies and the Caribbean coast of South America amounted to 131,000,000 nuts annually, equal to a supply of 75 tons of shells daily.

When we first began to build masks our demands for carboniferous material ranged from 40 to 50 tons a day of raw material; but by the end of the war, due to vastly increased mask requirements, we were in need of a supply of 400 tons of coconut shells per day. This demand would absorb the entire coconut production of the tropical Americas five times over. It was equal to one-tenth of the total coconut production of the Orient. Since transportation from the oriental countries was out of the question on the scale demanded by our mask program, it was evident that we were likely to be seriously embarrassed by the lack of raw materials; and, indeed, at no time before September, 1918, did we have on hand a reserve supply of shells and other charcoal materials that would last for more than a few days, though at no time after the start was the actual output of masks retarded by lack of these materials.

In building up our supply of coconut shells we naturally turned first to the resources in the United States. America normally consumes fresh coconuts at a rate sufficient to supply about 50 tons of shells daily. The war restrictions on the use of sugar had the effect of cutting down the consumption of coconuts, used largely in candy and cakes, and consequently one of our efforts was to increase by widespread propaganda the use of coconut. The "Eat-More-Coconut" campaign more than doubled the American consumption of coconut in a brief space of time; and the 50 tons of shells daily, which had been the original supply, grew in volume until in October, 1918, with the help of importations of shell, we averaged about 150 tons per day exclusive of the Orient.

The first heating of coconut shells to make charcoal reduces their weight 75 per cent. Therefore it was evident that we could most economically ship our oriental supply in the form of charcoal produced on the other side of the Pacific Ocean. For this purpose, in August, we established under the direction of an officer of the Chemical Warfare Service a charcoal plant in the Philippine Islands. From this plant agents were sent to Ceylon, India, Siam, and other oriental countries to purchase enormous supplies of nutshells. This work was only gaining momentum when the armistice was declared. As it was, the Philippine charcoal plant actually shipped over 300 tons of coconut shell carbon to the United States and had 1,000 tons on hand ready for shipment on November 11.

The method adopted in the Philippines was to burn the shells in long, shallow trenches. As soon as the smoke had disappeared and the flames came clear and lambent through the incandescent mass, the bed of coals was smothered by means of galvanized-iron lids thrown over the trenches. It is interesting to note that the coolies hired by the Chemical Warfare Service in the Philippines would not work at charcoal burning more than a few hours each day, because they declared that the heat from the pits would give them tuberculosis and other lung troubles.

Meanwhile agents and officers of the Gas Defense Division were searching the tropical regions of Central and South America for other nuts valuable for this purpose. The best of these was found to be the cohune or corozo nut. These nuts are the fruit of the Manaca palm tree. They grow in clusters, like bananas or dates, one to four clusters to a tree, each cluster yielding from 60 to 75 pounds of nuts. Cohune nuts grow principally on the west coast of Central America in low, swampy regions from Mexico to Panama, but are also found along the Caribbean coast. Before the war created a demand for cohune nuts none of them had ever been imported commercially in this country, although it is understood that France had a prewar commercial use for them.

The chief virtue of the cohune nut from our point of view was its extreme thickness of shell, the kernel of this large nut, which is 3 inches or more in length and nearly 2 in diameter, being relatively small. We were importing cohune nuts at the rate of 4,000 tons per month at the time of the armistice. A disadvantage in the use of cohune nuts was that their husks contained a considerable amount of acid which rotted the jute bags and also caused the heaps of nuts to heat in storage. The fire department at the Chemical Warfare Service nut storehouse at Astoria, N. Y., was kept busy putting out spontaneous blazes in the storage piles of cohune nuts. We also sent agents to West Africa and there arranged for the shipment of some hundred tons of palm nuts a month.

A third source of tropical material was in the ivory nuts used in considerable quantities in this country by the makers of buttons. In the button factories in this country there is considerable waste of this nut material, amounting to 400 or 500 tons a month, this waste including the nut dust which was useless to us and had to be screened out. The price of ivory-nut waste was high, because of the use of this material in the manufacture of lactic acid. Nevertheless, we used a considerable quantity of it.

Another great branch of activity in securing carbon supplies was undertaken in this country. In the search for fruit pits and for domestic nuts it was found that the quantity of apricot pits, peach pits, cherry pits (largely from the canning industry), and walnut shells on the Pacific coast amounted to 23,600 tons annually. We arranged for the whole Pacific coast supply of these commodities and converted a part of a San Francisco plant of the Pacific Gas & Electric Co. into a plant for the preliminary carbonization of 100 tons a day of these materials.

The next step was to turn to the consumers of the country and ask them to save their peach and apricot stones, their prune, plum, and olive pits, their date seeds, cherry pits, butternut shells, Brazil nut shells, and their walnut and hickory nut shells. The work of securing these and advertising the Government's need to the public was turned over to the American Red Cross. There was some question at the start as to whether the charter of the Red Cross would permit it to undertake such a war activity; but, since it was determined that this was purely a defensive operation, the legal forces of the Red Cross decided that the organization could go into a campaign of this kind.

"Help us to give him the best gas mask." That was the slogan which was carried on the posters, catching the attention of almost every person in the United States. More than 1,000,000 pieces of literature were distributed. The Red Cross established 163 collection points, and collection barrels appeared on the streets of practically every community in the United States. The Junior Red Cross, the Food Administration, and the Department of Agriculture gave valuable assistance. The Boy Scouts organized nut gathering parties. The governor of Massachusetts proclaimed November 9, 1918, to be gas mask day for the collection of carbon material, and 28 other States fixed gas mask days in November. Two reels of motion pictures were shown through the country. Journalists aided the campaign in newspapers and magazines. Frederic J. Haskin sent out a valuable article which was published in many of the important newspapers of the United States. One Oklahoma town took a day off en masse and gathered a whole carload of nuts.

This campaign started September 13, 1918, but was abruptly cut short on the 11th of November. Thus it is impossible to give exactly the result of it, since many of the scheduled shipments of nuts and fruit pits were canceled and found their way into fuel bins. However, at one time there were on the rails, en route to the carbon plant at Astoria, 100 carloads of materials supplied by the patriotism of the American people. It was estimated that some 4,000 tons were collected in this brief period, exclusive of the material from the California canning industry.

The procurement of the nuts, however, was but the first step in the production of carbon for use in our mask canisters, for after charcoal is first burned its pores are still filled with various impurities which may be summed up by the word "tar." When the charcoal was given a second heating, under careful temperature regulation, this tar was burned out, with the result that the charcoal itself became much more active in its absorption of gas. In fact, properly activated charcoal is more than absorptive—it is catalytic in its action toward the gaseous poisons used in the war, not only absorbing them but hastening their breakdown (digestion) into less injurious substances.

The activating of charcoal offered at the start considerably more of a problem than the question of making the charcoal itself, since activating had never before been conducted on a commercial scale. Two months of experimentation showed us that the best distillation of shells and pits for charcoal was that conducted in illuminating-gas-making retorts. The activation thereafter had to be done in special equipment permitting of fine control of temperature. The Government eventually spent more than $1,000,000 in a charcoal activating plant, providing for America the best protection known to science against the poisons which Germany had introduced into warfare.

The cement granules, which also had to go into the canisters, supplied another problem. We originally used a special soda-lime for this material, but only obtained a satisfactory product after Maj. H. W. Dudley, R.E., came to America as our British advisor and brought to us the British granule formula. The basis of this cement was lime, to absorb gases of an acid nature. Portland cement was used, to give hardness and prevent disintegration and the formation of dust in the canister. Then infusorial earth was added, to make the compound porous in texture. A little sodium hydroxide was put in, to increase the alkalinity of the mixture. Finally there was an infusion of sodium permanganate, which is a powerful oxidizing agent. This latter chemical was added as a precaution against arsine. Arsine and arsenical compounds were difficult to use in warfare, but the Germans had introduced them to some extent, justifying us in adding this protection.

In making the granules the sodium permanganate solution was mixed with the cement. The mixture was roughed out into slabs, allowed to set for three days, dried, ground up, screened to the proper size, and packed in drums for future use.

As has been noted, the charcoal and cement were packed in the canister in alternate layers. The cement had the virtue of working while the carbon slept—that is, the carbon was active when there were gases present to be absorbed, but the cement kept on thereafter, digesting the gases which had been absorbed by the charcoal. The cement was not quick in action, but it had a remarkable capacity for consuming some poisons.

To return to the chronological development of manufacturing facilities, after we had placed the contracts for the first 1,000,000 masks in the early fall of 1917, we began looking around for facilities for producing carbon and cement in the quantities which we should need in the near future. We found at Astoria, the district near Hell Gate at the junction of the East River and Long Island Sound in New York, the large gas works of the Astoria Light, Heat & Power Co. perhaps the largest illuminating-gas plant in the world. This was a subsidiary of the Consolidated Gas Co. of New York, which concern readily agreed to turn over to the Government some of its retorts and to permit the construction of a Government-operated plant on its grounds. We might have been seriously delayed in the production of gas masks except for the extraordinary and continuing efforts of Mr. W. Cullen Morris, Chief Construction engineer of the Consolidated Gas Co., and Mr. Addicks, its vice president. It was due to Mr. Morris that a $150,000 granule plant was constructed, heavy complicated equipment installed, and operations started in the short space of 30 days.

Let us now go back to the history of actual mask production. At the start it was estimated that when the Hero Manufacturing Co. had reached full capacity it could assemble and turn out 6,000 masks a day. The fuel shortage and the railroad congestion of the late fall and early winter of 1917-18 hampered our supplying the Hero Manufacturing Co. with parts, until the mask production, averaging 2,430 a day as it had in November, dwindled to 1,500 a day in December. The Goodyear Co. at Akron had meanwhile established its Akron-Boston motor track line. This was put at the service of the Gas Defense Division, hauling various supplies from both Akron and Boston to the assembling plant at Philadelphia. Sometimes in the mountains of Pennsylvania the trucks would be blocked in snow and the patriotic citizens of the community would get out with shovels and work until the supplies again started on their way.

Slabbing the doughlike mixture of carbon and spreading it on screen-bottomed trays at carbon plant No. 2.