Science: Mars in White Smock

On April 22, 1915 a brisk wind was blowing from the German lines in the Ypres sector toward the trenches held by French and Algerian troops. Shortly after 5 p. m. the Allied soldiers saw a sinister greenish cloud rolling toward them across No Man’s Land. Some of them broke and ran; thousands stuck to their posts or fled too late. Soon the trenches were heaped with gasping, choking, dying men. The gas was chlorine, 168 tons of which were released that day from 5,730 cylinders over a four-mile front. There were 15,000 casualties including 5,000 deaths.

This was the first mass murder ever effected directly by a chemical agent in war.* The Germans made a 3½-mile breakthrough, would have penetrated much more decisively had the German high command had more confidence in their new weapon before it was tried.

Old Stuff. The possibilities of gas as a military weapon were thought of long before the World War. During the U. S. Civil War, Brigadier General W. N. Pendleton of the Confederate Army wrote to an ordnance officer asking whether “stink shells” which he had seen mentioned in a newspaper could not be used in 12-pounder howitzers and whether “the explosion can be combined with suffocating effect of certain offensive gases.” The stink shells were not tried. At The Hague Conference of 1899 an agreement banning the use of gas projectiles was signed by 24 nations including Germany. After the chlorine attack at Ypres, Allied and U. S. newspapers roared that this new deviltry was a violation of The Hague agreement. Literally it was not, since the chlorine was projected from cylinders. This fine distinction was soon forgotten and both sides began loading gas enthusiastically into artillery shells.

Altogether 36 gases were used in the War, of which about half a dozen showed high efficiency. All these chemicals were known before the War. Phosgene, for example, was first made by British Chemist John Davy in 1812. Making gas into a war weapon was not a matter of finding new compounds but of manufacturing known compounds on a great scale. With their splendidly developed chemical industry, the Germans had the edge throughout and Allied gas warfare was largely a series of belated retaliations. In their March 1918 offensive against the British the Germans fired half a million “Yellow Cross” (mustard gas) shells in ten days. In July gas shells constituted half of all German projectiles fired. Their factories could not keep up with this ravenous demand and a shortage ensued which greatly facilitated the victorious advance of the Entente armies. When the Armistice was signed. German ammunition dumps were found to contain less than 1% of mustard gas projectiles.

Thus, like the airplane, chemicals emerged from the War as a major military instrument. With the post-War development of fast, long-range bombing planes, the prospect of aero-gas attack on cities has become a horrid spectre held up to palpitating civilians by excited publicists. Military experts in chemical warfare cry out to a man that this spectre has been grossly exaggerated.

Last week Lieut.-Col. Augustin M. Prentiss, Ph. D., of the U. S. Army’s Chemical Warfare Service published a 739-page treatise entitled Chemicals in War* which was hailed by colleagues as the most comprehensive work on the subject in English. † In this book Lieut.-Col. Prentiss describes in minute detail the tactics and accessory equipment of chemical warfare, the organization of chemical troops, the chemicals used in the World War, their composition, manufacture, military value, physiological effects and probable role in future war. A chapter on the protection of civil populations is contributed by Major George J. B. Fisher.

Flame & Smoke. High explosives are chemical compounds, of course, but they are not in the special province of the chemical warfare service. This branch concerns itself with 1) toxic gases; 2) incendiary substances; 3) smoke screens.

Incendiaries were the earliest chemicals used in war. The first flame projector (glowing coals, sulphur and pitch) got into action at Delium in 424 B. c. Thermit, a mixture of iron oxide and powdered aluminum which burns at 3,000° C., was the chief World War incendiary. It was used in conjunction with oil to spread fires which the thermit started. Since there is not much of importance to burn on a battlefield, Author Prentiss believes the chief future use of thermit and other incendiaries will be against cities.

Gas. War gases are classified as 1) lacrimators (tear-gas); 2) systemic toxic agents (blood poisons); 3) lung injurants; 4) respiratory irritants; 5) vesicants (blister-producers). As War gases the first two are the least destructive. Tear-gases have some value because very low concentrations force masking, with attendant loss of efficiency and morale; 6,000 tons of lacrimators were used throughout the War.

It should be a comfort to common soldiers and civilians, if not to military strategists, that the most poisonous gases in the laboratory, the systemic toxic agents, are of little use in war. Hydrocyanic acid, now used to execute criminals in closed chambers, is so volatile in open air that it tends to disperse harmlessly. The French started using hydrocyanic acid in 1916 and put over 4,000 tons. Casualties were practically nil.

Lung Injurants are gases which cause pulmonary edema, which means that water pours into the lungs, suffocating or “drowning” the victim. Chlorine is a lung injurant. Phosgene (carbonyl chloride) is a much better one, not so irritating at first but ten times more toxic. This gas was first used by the Germans late in 1915 and then adopted by the Allies, while the Germans switched to diphosgene which is less stable than its chemical brother but easier to fill into shells. The phosgenes accounted for 80% of the War’s fatal gas casualties. Nevertheless, it had a tell-tale odor, efficient anti-phosgene, masks were developed, and wet weather weakened its effect, made it visible. Author Prentiss does not regard its future chances highly.

Chlorpicrin is a lung injurant which incidentally causes vomiting, strangulation and temporary blindness. It was difficult to guard against chlorpicrin in the War because none of the chemicals except charcoal in the gas-mask canister would remove it from the entering air.

Respiratory Irritants cause sneezing and vomiting. They are not strong casualty producers by themselves, but when first employed they penetrated masks, made it intolerable for soldiers to keep their masks on and thus exposed them to lethal gases like phosgene which were fired in the same bombardment. Favorite irritant of the Germans was diphenylchlorarsine. The Entente developed a similar one called diphenylaminechlorarsine (Adam-site), but never got it into action. These irritants are not stopped by any canister chemicals and an extremely efficient filter, which makes for hard breathing, is necessary.

Vesicants are blister-producers. Mustard gas, which is really an oily liquid, was called “the king of battle gases” although it was seldom fatal unless its vapor was inhaled. Masks were of little use, since mustard gas penetrated ordinary clothing and shoes easily, raising huge red welts which sometimes ulcerated and always laid the soldier low for a month or more. When splashed around by shells it contaminates everything it touches for days. It is therefore more valuable for defense than offense, since it is impracticable for attackers to move forward through a mustard-shelled area. Mustard was not introduced until 1917 and comprised less than 10% of the total gas shells fired in the War. Yet it accounted for 400,000 casualties, which was one-third of the total gas casualties. It took only 60 Ib. of mustard to produce one casualty, as against 230 Ib. of lung injurants and 500 Ib. of high explosive.

Mustard was far & away the most important vesicant in the European arena. In 1918, however, the U. S. was manufacturing a powerful blister-liquid called Lewisite, none of which reached the front. Because of its arsenic content, Lewisite may poison the blisters it produces. Author Prentiss declares that 30 drops of Lewisite splashed on a man’s skin would be fatal. It is more volatile and less persistent than mustard gas, however, and if no arsenic poison sets in, its wounds heal more quickly. Author Prentiss believes that under favorable” conditions Lewisite would prove superior to mustard. British experts disagree with him. Lewisite is certain to get a thorough tryout in any future war between major powers.

Cities Gassed? In 1931 Biographer Emil Ludwig published in the Satevepost a scarehead article in which he stated: “Twelve big bombs of Lewisite gas dropped on Berlin or Chicago would be enough to destroy all life in those cities.” Chemical officers jumped on this statement as utter nonsense. Author Prentiss points out that to lay down any sort of effective (not lethal) contamination it would be necessary to deposit 10 Ib. of vesicant liquid on every 100 sq. yd.

Chemical officers will admit—or even argue—that it is conceivable that some foreign power or combination of powers might drive the U. S. Navy to cover, bring up their aircraft carriers to 50 or 100 miles from the coast, attack New York. Philadelphia, Washington, Chicago, St. Louis by air. Lieut.-Col. Prentiss holds that, if such a fantastic possibility materialized, incendiary bombs and high explosives would be more harmful than gas. To be effective, gas requires masses of human beings at ground level and without adequate shelter. War gas is heavy. Even if the enemy had the tremendous number of planes and material to blanket one square mile of Manhattan, the inhabitants would need only to seek upper stories of houses and buildings, close their windows and wait for masked degassing squads to clean up.

Some experts believe that the enemy would be content to smear parts of New York with mustard and Lewisite. Mustard gas is not hard to neutralize (chloride of lime) but it is hard to find and hangs on for a long time. Without protective clothing it would be dangerous for civilians to venture into the streets, and the enemy would presumably be content with the resultant paralysis of the city.

If a general war broke out, Author Prentiss believes that war gases which have proved efficient would be picked up where they were dropped in 1918. No one can say, of course, that a supergas has not been developed in secret, but this does not seem likely because the realm of possible chemical compounds has been too well explored. Moreover, nothing could be plausibly called a supergas until it had proved itself in practice. Many an idea that looked brilliant in the laboratory has been a dud on the battlefield.

*It was not, however, the first use in the War of noxious gas. In August 1914 the French began shooting rifle grenades containing the tear-gas ethylbromacetate and later used another lacrimator, chloracetone, in both rifle and hand grenades. First German gas used (January 1915) was the lacrimator zylyl bromide (“T-Stoff”). The casualty effect of these was negligible.

*McGraw-Hill ($7.50).

† German masterwork on the subject is Der Chemischc Krieg by Dr. Rudolf Hanslian.