Chemistry at the Front


SOON after the opening of hostilities, this world-war was referred to by certain writers as ‘a chemists’ war.’ While this phrase, like many of its kind, implies too much, it gives appropriate emphasis to the part which the chemists are playing in the great struggle.

Ever since the tension of the bowstring as a means of propelling projectiles was displaced by the expansive force of the highly heated gases generated by explosives, the chemist has had to assume a large responsibility for the successful supply of fighting materials and the outwitting of the enemy. With the progress of the centuries, this responsibility has grown in intensity and has become so ramified as to include the development, not only of explosives, but also of projectors and projectiles, the production of an endless variety of materials for use at the front, and the equally important task of providing for the maintenance of adequate food-supplies, and of necessary industrial activity at home.

And to all this has now been added a task which, in view of our general belief in an honorable regard for international conventions, had been looked upon as outside all bounds of probability, namely, that of pitting our best brains against those of the enemy, for the discovery of more and more insidious and cruelly poisonous gases, and of methods to protect our own brave fighters from each new and more vicious device of our opponents. However much we may condemn gas-warfare as unsportsmanlike, and deplore the expenditure of intellectual effort which it is demanding, we must play the game, and in this phase the war is preeminently ‘a chemists’ war.’

The importance of the chemist in our own military organization has been definitely recognized by the creation of a Chemical Service Section of the National Army, with a lieutenant-colonel as its ranking officer, and provision for a personnel of about 1300 officers and men. The important functions of this section are the correlation of information accumulated at home and at the front, and the induction into chemical service of drafted men with chemical training. The establishment of this section not only is a distinct step forward in the interests of military service, but affords a too-long delayed recognition of the parity in importance of chemical engineering with that of the other and older engineering professions.

Among our allies it is known to be true, and among our enemies it must be true, that chemists are almost to a man throwing their whole and best energies into the solution of war-problems. Plans are already maturing for the recruiting of the forces of our allies by sending men to their chemical laboratories, as well as to fight in the field.

If the chemist is concerned with the problem of feeding the guns of the expeditionary forces, he is no less concerned with a problem which has become equally serious, that of feeding the bodies of the fighting men, and of those of the entire population of the allied nations. Conservation and the regulations of our food-administrators are topics of daily thought and conversation. With these affairs the chemist has much to do, through the improvement of the preparation of food-stuffs and by providing safeguards against frauds and against the general introduction of insufficient dietaries.

But, besides conservation, there must be stimulation in production of foodstuffs, notably through intensive agriculture. It has been stated that a reduction of the cost of soluble nitrogen compounds to a price comparable with that prevailing in Germany before the war, would add a billion dollars to the annual value of our crops. The significance of this statement to-day does not, of course, lie in the increase in monetary worth, but in what it would represent as a war-resource. This phase of the chemists’ problem is, moreover, closely linked with that of the ammunition-supply. Nitric acid and ammonia are necessary for both ammunitions and fertilizers, and the failure to maintain an adequate supply of both would be fatal to the success of any of the warring nations.


An explosion is the result of the rapid generation of gases which are at the same time highly heated, causing them to expand with great force, in accordance with well-recognized principles of physics. If, for example, a flame is applied to a mixture of illuminating gas and air, the temperature of the gasmixture at a point near the flame is raised to the so-called ignition point, chemical combination ensues, and new and highly heated gaseous products result. If the gas-mixture is confined, the confining walls are often disrupted.

The explosives in common use differ from the mixture just described, in that they are not gaseous at the start. They are sometimes liquids, but are generally solids, and are made up of bodies which, when they are subjected to heat, or to certain sorts of shock, promptly go to pieces, yielding mostly gaseous products and liberating large quantities of heat. Almost without exception these explosives are made by the action of nitric acid upon such materials as glycerine, cellulose (absorbent cotton is nearly pure cellulose), or certain materials, like toluene, derived from the heating of soft coals out of contact with the air, as in the production of illuminating gas. They are among the socalled ‘intermediates’ from coal tars.

While to the casual observer the breaking down of the various explosives would appear to proceed p Tactically instantaneously in all cases, accurate measurements show that there are appreciable differences in the rates of decomposition, and these differences determine the type of usefulness of a particular explosive. For example, a mixture of gasolene vapor and air is an efficient mixture for the development of power as applied to the piston of the engine of an automobile; whereas a mixture of hydrogen and oxygen, while developing greater explosive force, does so with such rapidity that this energy cannot be effectively taken up by the mechanism of such an engine, and is wasted as a dangerous disruptive force on the walls of the cylinder. An explosive which is designed to produce a maximum of disruptive effect, as in shells, mines, or torpedoes, or in sapping or mining operations, must be of the rapid type known as a ‘ high explosive.’ A propellant, on the other hand, must be of such a character that the decomposition goes on with progressively increasing rapidity, thus steadily increasing the pressure developed behind the projectile, until it acquires its maximum velocity at the moment when it leaves the barrel of the gun.

To the chemist belongs the responsibility for the scientific development and improvement of these explosives. The problems arc many-sided. It is not enough to produce materials which, in a qualitative sense, exhibit properties which would class them with one or the other of the types of explosives just outlined: their effects must be quantitatively measured, and must be capable of exact reproduction at will. This is rigidly true of the propellants, upon the performance of which the accurate placing of shells, when the range has been determined, absolutely depends. The limitations laid down in the specifications for such explosives permit but a very small percentage of variation in the pressure produced in the chamber of the gun. This uniformity, in turn, can be attained only by the most rigid scientific control of the manufacturing operations by the chemist, and the utmost care in guarding against subsequent deterioration during the interval between manufacture and use. Indeed, the latter phase of the problem is one of great significance. Explosives are, almost or quite without exception, composed of substances which are endothermic in character: that is, heat energy is absorbed when they are formed, and this heat is liberated when they decompose. Heat, moreover, accelerates all chemical changes. Hence, if any (even a very small) part of an explosive mass begins to break down from any cause, the heat liberated promotes the rapidity of the change, and this, in turn, is communicated to neighboring portions, until the entire mass may be involved and destroyed.

So far as it is humanly possible to do so, all exciting causes must be foreseen and forestalled; and the lack of stability during storage has necessitated the discarding of many materials otherwise of great promise. Moreover, apparently slight variations in conditions of manufacture, due to ignorance or carelessness, may result in an imperfect product, which will begin to undergo spontaneous decomposition in storage, with a final result like that outlined above. Conditions such as these have been the cause of many mysterious explosions.

As an instance of extreme instability, the behavior of a substance known as nitrogen iodide may be cited. This compound explodes with great violence if touched with a feather, — a literal instance of being ‘tickled to death,’ — and often it is exploded by the mere friction of the air when moved from one spot to another. Such sensitiveness as this obviously places a substance outside the bounds of practical usefulness; but all explosives are, in the very nature of the case, unstable, and their preservation involves the study of factors which differ from this case in degree rather than in kind.

To attain the extreme velocities and the enormous ranges concerning which we almost daily find our credulity taxed to its limit, it is obvious that the tem peratures and pressures developed within the chambers and barrels of the heavy guns must be very high. As has already been pointed out, both must be known within small limits, and be producible at will. Stimulated by these great temperatures, the products of decomposition of the explosives exert an erosive action upon the interior of the chamber and barrel of the gun, and soon injure and ultimately destroy the rifling. It is this, with the effect of temperature on the steel itself, which limits the life of the guns; and it is, again, the chemist’s task so to choose his materials, for both the fabric of the gun and the explosive charge, that there shall be a minimum of erosion with a maximum of ballistic efficiency.

Nitroglycerine is doubtless the most generally known, by name at least, among the high explosives. It was first manufactured on a large scale by Alfred Nobel, of peace-prize fame. It soon proved to be a treacherous substance to transport in liquid form; but Nobel found that the risk could be greatly reduced if the liquid is absorbed in a silicious earth. Nowadays wood-pulp and other absorbent materials are employed, and constitute what is known as dynamite. But nitroglycerine, if used alone as a bursting-charge for shells, has not proved itself to be satisfactory, and has been displaced by such materials as picric acid, and, notably, trinitrotoluene, which is frequently designated as T.N.T. This substance is distinctly less unstable. It can be melted and poured into shells without danger. Picric acid also may be handled without great risk, when pure. It tends, however, to react upon metals, with the formation of derivatives of picric acid (picrates), which are treacherous, and this circumstance has led to serious explosions. While trinitrotoluene is somewhat less powerful than picric acid, its use is more general at present.

Recently it has been found possible to secure excellent results from an explosive called ‘amatol,’ which is made by mixing with T.N.T. a considerable amount (even as high as eighty-five per cent) of ammonium nitrate. This common and apparently innocent laboratory reagent becomes an effective disruptive agent when its decomposition is once started by the explosion of the admixed trinitrotoluene. Aluminum powder, which in burning generates an exceptionally large amount of heat, is also sometimes added, and this mixture is called ‘ammonal.’

The raw materials from which picric acid and trinitrotoluene arc made are phenol, or carbolic acid, and toluene. Both are constituents of the tar resulting from the heating of soft coals in retorts, to produce illuminating gas and coke. Great quantities of coke are used in the production of iron and steel; but, in the past, much of this has been made in what are known as ‘ bee-hive’ ovens, from which the volatile products from the heating of the coal, including phenol and toluene, escaped into the air. At the present time, much progress has been made in the construction of closed retorts for the coking of these coals, thus making it possible to collect the volatile products. By this means the available supply of toluene is much increased. Under the best of conditions, however, some toluene, on account of its volatility, passes on with the illuminating gas, and auxiliary plants are now being installed in some of the larger cities to strip this toluene from the gas before it passes to the mains.

Picric acid is chemically known as trinitrophenol. Phenol is more commonly called carbolic acid. While phenol is found in coal tar, the amount is not sufficient to provide an adequate supply to meet the demand for picric acid; and to meet the deficiency, it is necessary to resort to the synthetic preparation of carbolic acid from benzene (benzol), which is a somewhat more abundant constituent of coal tar. The synthetic processes employed are akin to those which the chemist uses to transform the ill-smelling and unsightly coal tar into the varied dye-stuffs which add so much to the cheerfulness of life, or into the synthetic drugs upon which physicians rely for the alleviation of pain and for the maintenance of antiseptic conditions in home and hospital.

The handling of both picric acid and trinitrotoluene, while reasonably safe if intelligently done, so far as danger from explosion goes, has other disagreeable features. The operatives gradually absorb the material into the circulatory system, and in time it acts as a poison. The trinitrotoluene eventually affects the liver, and jaundice ensues, with such intensity that the operators often turn a bright yellow. These cases are not infrequently fatal, and all are serious and of long duration, with doubtful final issue. In England thousands of women are engaged in the shell-filling plants, and they have shown great courage and loyalty in taking their share in this work, in the face of inevitable disfigurement, or permanent disablement.


But the problem of the explosive shell does not end with the mere selection of a material to fill it. If its mission is to shower the enemy with shrapnel, the chemist must so choose his exploding charge as to give efficiency in force and distribution; if the shell is to destroy barbed-wire entanglements, its fragments upon bursting must be relatively large and heavy, which means a different shell-design and bursting-charge. The gas-shells, referred to later, also present many peculiar problems, and there are doubtless many more, peculiar to torpedoes and mines.

Among the modern explosives, gunpowder has lost its former prestige. In its development of explosive force it lies between the high explosives, like nitroglycerine, on the one hand, and smokeless powders on the other. Gunpowder fell from its former high estate largely because it gives aid and comfort to the enemy by enabling him to locate the guns of his opponent by the smoke which it produces.

In the search for a smokeless powder, that is, for an explosive which on decomposition would yield only gaseous products, attention was first turned to gun-cotton, or nitrocellulose. Raw cotton may be chemically treated for the removal of nearly all materials except what is chemically known as cellulose. It is similar to starch and sugar in its chemical character, and explosives can be made also from these latter materials, although none are of much importance. The cotton, after such chemical treatment, is like the familiar absorbent cotton. If this is treated with a mixture of nitric and sulphuric acids, it is converted into nitrocellulose, a material which is, incidentally, used in the manufacture of celluloid, in the dressing of patent leather, and in collodion.

Indeed, it has been made a reproach to the chemist, that he has allowed his art, which first brought carbolic acid to the surgeon’s aid, and collodion (liquid court-plaster) to protect our wounds, to be turned to the production, from these same materials, of death-dealing explosives. But, as Dr. Baekeland has pointed out, it would be equally logical to condemn the art of printing, because it has been, and may be, used for the dissemination of lies and calumnies.

After washing and drying, which require great care, nitrocellulose is capable of use as an explosive. Curiously, the microscopic structure of the cotton is hardly altered by this treatment. It has the same open texture, and, if ignited, or detonated, the decomposition proceeds through the mass with such rapidity that nitrocellulose, thus prepared, proves to be a high explosive rather than a propellant, and is so used to-day in considerable quantities. But it has been found that, if nitrocellulose is dissolved in some solvent, or mixed with enough solvent to cause gelatinization, the resulting product, on drying, has the desired properties of a propellant: that is, it decomposes relatively slowly. Still later, it was found that admixtures of nitroglycerine with nitrocellulose gave desirable results, and the smokeless powders of to-day, known by various trade names, such as cordite, poudre B, etc., are blended mixtures, the composition of which is determined only after the most careful laboratory and ballistic tests. Each type of gun, from the small arm to the largest cannon, requires exact and extensive study. In these investigations, again, the chemist is indispensable.

A smokeless powder, if ignited in the open air, burns relatively slowly. A stick of it may safely be held in the fingers until nearly consumed; but at the high pressure and temperatures within the guns, this combustion proceeds with relatively great velocity. The smokeless powders are usually ignited by a primer, which is frequently a small charge of black gunpowder. Most other explosives are fired by means of fulminates, the most common being mercury fulminate, which is made from mercury, nitric acid, and alcohol. These fulminates explode by friction, or a blow, and produce sufficient heat locally to detonate the explosive charge. The fulminates are sensitive rather than powerful. They demand the greatest caution in both manufacture and subsequent handling. They must explode with unerring accuracy when struck by the exploding mechanism, as is evident in the case of the machine-guns used on aeroplanes, the firing mechanism of which is so synchronized with the revolutions of the driving shaft, that the bullets pass between the blades of the propellers when the latter are revolving rapidly, and the slightest retardation in firing would be attended by fatal results.


It is within the bounds of truth to assert that the changes in both munitions and ammunition which have taken place since the beginning of the war have equaled or exceeded those of preceding centuries. The rapidity of development, and the adaptation to these constantly changing conditions and demands, have been equally marvelous among all the warring nations; and these changes are still going on to an extent which makes assertions of today almost obsolete to-morrow. But in no particular has this been so true as in the gas-warfare which has assumed an importance scarcely secondary to the use of explosives and missiles.

The first gas-attack was of the socalled ‘drift-gas’ type. Chlorine gas was discharged in quantity from the enemy trenches, and was carried by a favoring wind over the allied trenches, with disastrous results. Chlorine is a heavy gas, green in color and exceedingly irritating to the membranes of the air-passages, even at great dilution. This gas may be liquefied under high pressure in steel cylinders; and great numbers of these cylinders were placed at intervals of a few feet along the front of the enemy trenches, and pipes laid outside, opening toward the trenches of the Allies. The gas was simultaneously discharged from these openings, and with a light wind it held close to the ground. The effect was nothing less than appalling. It is said that, had the enemy realized the full effect of this gas-attack and followed it up, they could have pushed completely through the Allied lines. It is probable that they were not themselves adequately protected against the gas, and were uncertain as to what they would find in the gassed area.

This attack, marking, as it did, a new and evil epoch in military affairs, produced first a feeling of incredulity, which, however, soon gave place to the utmost exertions to devise means of protection, and later to devise varied and more vicious materials for offensive use in this relentless form of warfare. Drift-gas attacks, while still employed, have largely given place to gas shells, which are fired from guns or mortars, or used as hand-grenades. The shells which have been used contain as much as six pounds of materials which are themselves easily volatile, or are atomized by the bursting of the shell, and thus impregnate the atmosphere around the spots at which they explode. They can, of course, be placed with the same accuracy as a shrapnel or other explosive shell, and such gas-shells are now used in great numbers before an attack in force, and are also intermingled with the explosive shells during an attack. Because of the penetration of the gases into dug-outs and gun-shelters which are practically proof against missiles, positions may be captured and gun-crews put out of action after withstanding long periods of bombardment.

Nearly all the materials employed in gas-warfare will produce fatal results if inhaled in sufficient concentration, and the aim of the warring chemists is to devise new gases which will pass through the masks in use by the enemy before they can be detected and the troops safeguarded, when such safeguarding is possible. Certain gases have, however, for their more immediate object, the irritation of the eyes (the lachrymatory gases, one part in a million of air being effective), temporarily blinding the victim; others are designed for the irritation of the nose (the ‘sneeze-gases’), making it almost impossible for the fighter to overcome the tendency to throw off his mask; and others again, for the production of burns when in contact with the flesh, which are of a most distressing character, and, even if they do not cause death, incapacitate the victim for service for a period of months. The last-named gases are likewise toxic and lachrymatory to a high degree. The so-called ‘mustard-gas,’ a compound somewhat similar in character to mustard-oil, but far more of an irritant, has proved particularly destructive, and doubtless accounts for many of the casualties in recent attacks. The mustard-gas is discharged in liquid form and penetrates ordinary clothing, even if the masks prevent its inhalation. It also saturates the ground, and troops taking shelter in shell-holes are often burned by contact with this ground.

It is often true that the harmful effect of the poison gases when inhaled is not immediate, but is the result of a slow interaction between the moisture of the lungs and the chemical employed. One, methyl sulphate, for example, yields wood-alcohol, a violent poison, and sulphuric acid. The men are frequently incapacitated hours after a gasattack which at the time appeared to have been without serious result. The physiological effects are usually insidious and cruel. Smoke-shells containing sneeze-gas’ are sometimes first used, and these are immediately followed by shells containing violently toxic gases. If the men are affected by the ‘sneezegas before the masks are put on, it is very difficult for them to keep them on, because of the continued paroxysms of sneezing.

Chlorine itself is now comparatively seldom used alone, but nearly all the poison gases are compounds containing chlorine, and the ability’to supply adequate quantities of this gas, which is obtained by the electrolysis of a solution of table salt, is an important factor in the prosecution of the war. The processes for its production have been well worked out by the electrochemist. It is a question of installation of adequate large-scale apparatus.

The task of the chemist naturally resolves itself into the development of protective and preventive devices (the defensive side), and the devising of new toxic gases (the offensive side). At the lime of the first gas-attack the Allied forces were without any means of protection, since, although some inkling of a possible use of poison gases had been obtained, it was not believed that those provisions of international agreements which were intended to eliminate such practices would be violated.

Only the simplest expedients could be immediately employed. After a number of gas-attacks in April and May, 1915, there were few attacks until December, 1915, and in that interval, with incredible rapidity, comparatively efficient masks were devised and manufactured, and these are being constantly perfected. Cut even at best, they are a serious handicap to the activities of the men, and much of the efficiency of gas-warfare comes from the depressing effect of wearing the masks for long periods. This is known as ’neutralization’ of the opposing infantry force; and even if it constituted only an annoyance, it would be remarkably effective. When, for example, ammunition and supplies have to be brought to the front, there are almost inevitably exposed points, or cross-roads, where great confusion of traffic occurs. These spots are frequently discovered by the enemy, and by planting a few gasshells in the vicinity, the workers are obliged to don their masks, which, in these night operations makes confusion worse confounded, and may even cause serious embarrassment in the delivery of needed supplies.

The masks now used are nearly all of the canister type: that is, the inhaled air is drawn in through a canister containing certain materials which will react with, or absorb, the gases before they enter the mask itself. This mask consists of a close-fitting fabric, containing usually more or less rubber in its structure, and held in place by elastic straps over the head. The exhaled breath escapes from the mask through a rubber valve which opens only from pressure from the inside. The time allowed to put on the mask, when slung by a strap from the neck, is under ten seconds. It is carried in a canvas case, and when the forces are within two miles of the front, they are required to wear the outfit in the ‘alert’ position, ready for instant use, night and day.

An important feature which has been the occasion of much scientific study is the eye-piece of the masks, to avoid dimming from the moisture accumulating within. Anti-dimming preparations have been found, and lately, as the result of many experiments, materials devised which reduce this difficulty to a minimum, under ordinary conditions of use.

Great improvements have been made in the effectiveness of the absorbent material used in the canisters, and this, in turn, has increased several fold the general efficiency which it was possible to attain at the time when the manufacture of the masks was first undertaken, and hence to diminish the amount of material to be placed in the canisters. The significance of this will be understood when it is realized that there is a considerable friction to overcome when the inhaled air is drawn through the canister. This was so great in the earlier masks, that it made necessary a suction on the part of the wearer of the mask equal to that required to raise a column of water in a tube to a height of six inches; an effort not incomparable with that made by many asthmatic sufferers to draw air into the lungs. This frictional resistance has been materially lessened by the improvement in the protective materials, and every reduction, however slight, is a great boon to the troops.

The materials used in the canisters are selected to react with gases of an acid character, and with those capable of destruction by oxidation, a process like that generally known as combustion. Much reliance is, however, placed upon the absorptive power toward gases exhibited by many porous substances, notably, high grades of charcoal. The principle is the same as that utilized in the ‘charcoal filters’ sometimes attached to our faucets to clarify watersupplies.

Of late a new problem has been presented, because of the use of gases in the form of ‘smoke-clouds,’ which easily pass through the protective materials contained in the canisters. This has necessitated the addition of another filtering medium, and has necessarily added somewhat to the resistance to be overcome.

How serious this ‘neutralization’ of troops through the continuous wearing of masks may be, is illustrated by the conditions which obtained before one of the recent violent attacks on the Western Front. It has been stated that the enemy fired gas-shells (mainly mustard-gas) at the rate of two hundred thousand shells per day for four days, each shell probably averaging about five pounds of material. While the gasmasks will protect the wearer from the inhalation of this gas, they must have required one or more renewals during this period. This attack was followed by a smoke-cloud attack which necessitated the use of the extension filters, thus subjecting the troops to added labor in breathing, after days of constant use of the mask. The physical strain under such conditions cannot fail to have been severe. It is not, however, to be supposed that the enemy was allowed to spend his time in full comfort.

As a means of detecting the approach of a toxic gas, canaries and white mice are placed in the trenches, as they are peculiarly sensitive to these chemicals and show signs of distress from dilutions which are unnoticed by man, especially when the gases are nearly odorless.

Of the offensive side of this gas-war it is obvious that little can properly be made public. There is reason to believe that our American chemists are making valuable contributions in this field.


Another type of gas-problem is that presented by the necessity for protection against the gases resulting from the explosion of shells aboard our warvessels, and from those gases which issue from the guns when the chambers are opened for recharging. To this must also be added the risk from poison-gas shells which may be so designed as to penetrate armor-plate before explosion. Carbon monoxide is a notable constituent of these gases. So long as the ventilating systems are intact, the men in the turrets (where the guns are situated) are protected; but in the event of damage to such systems, other protection, in the form of masks, is needed.

Again, the submarines present a series of problems. For example, the presence of hydrogen, which may escape from the storage-batteries and will easily form explosive mixtures with air, must be promptly detected. These are but two of many similar problems coming from the navy with which the chemist is busy and for which solutions have been found.

Much has been done in the production of efficient smoke-screens for use in the trenches, and notably as a protection against submarine attack. The chemists have perfected devices by which combinations of chemicals are used to produce clouds of remarkable density, some white, some black, which hang for a considerable period above land or water, and effectually obscure what is going on behind them.

To determine the accuracy of artillery fire, it is necessary for the aerial watchers to be able to trace the path of a portion of the shells by day or by night. This may be accomplished by attaching to some of the shells inflammable materials—phosphorus for example, which is ignited when the shell leaves the gun and leaves a trail of fire at night, or of white smoke by day; or the point at which they land may be indicated by a similar phenomenon, taking place at the moment of impact. Aircraft of the type of the Zeppelins, or the observation balloons, are filled with hydrogen, and it is to this that their great vulnerability is largely due. Incendiary bullets, carrying inflammable materials, on piercing the envelopes of these craft, ignite the hydrogen, and destruction follows. Bullets and shells used in anti-aircraft guns must also be traced to determine the effectiveness of an attack, and this is accomplished in a similar way.

If the advent of a ‘safe and sane Fourth’ has served to restrict the activity of the pyrotechnic industries in this country, the war has called into service the knowledge and skill of their chemists and operators. Signals for night use, and those that develop colored smokes for day use, incendiary bombs for the ignition of buildings and of grain-fields, and stars for the illumination of battlefields, are among the many devices that must be produced in enormous quantities, and with the highest attainable degree of uniformity and reliability. Pyrotechnic research is today an important division of the work which is going on in various laboratories throughout the country. The educational institutions and many individuals and business organizations have placed their facilities at the command of the government, and in these laboratories, as well as in those of the government itself, a large corps of chemical investigators is busy with the study of the methods of safeguarding our forces against gas-attacks, and in perfecting procedures which will lead to the production of those toxic gases which have already proved effective, as well as of such new ones as may give promise of even more deadly effects.

It is a matter of common knowledge that we in the United States were confronted with a most serious situation with respect to dye-stuffs at the beginning of this war, on account of our dependence upon imported colors. This situation has been splendidly met by the chemists of the country. But the situation was serious in other countries also, for the demand for dyes for uniforms was made on an unprecedented scale. The chemists in the Allied countries rose to the occasion, and produced synthetic indigo for navy blue, using in part new processes, and also produced the necessary dyes for the khaki and olive-drab uniforms. This, although simple in the telling, involved extensive and intensive modifications of manufacturing processes and plants, and is fairly representative of many of the industrial crises which the chemist has been called upon to meet since the opening of the war.

Whether the rôle of the chemist in this war transcends in importance that of the members of other professions, to such an extent as to warrant the designation ‘a chemists’ war,’ may reasonably be questioned; but, there can be no doubt that the contributions of the chemist to the prosecution of the war, of which a few typical instances only have been outlined, fairly substantiate a claim to a position of great responsibility for its successful conduct, at home and in the field. Much has been done, and much must still be done. Mind must be pitted against mind while the struggle lasts; and when it ends, and our country realizes, as it must if it expects to hold a dominating place in civilization and industry, that scientific methods alone afford a sound basis for federal and industrial development, the achievements of the chemist in the war should entitle him to increasing respect and to a highly responsible share in national life and in the councils of those who will direct our national policies.