developing. This gives a faint idea of the elaborate preparations required. They must have been doubly arduous and lengthy on the very first occasion of cloud gas attack.

[1] Die Technik Im Weltkriegre. Publisher: Mittler, Berlin, 1920.

German Opinion of Results.—We can now regard the chlorine attack of April 22, 1915, as the first and successful result of a huge German experiment on a new method of war, the pioneer work of which actually began at (if not before) the outbreak of war. Quoting again from Schwarte: "G.H.Q. considered the attack near Ypres to he a successful experiment. The impression created was colossal and the result not inconsiderable, although it was not fully utilised from the tactical point of view. It was obvious that we had gained a great advantage; the enemy was not sufficiently prepared with defensive measures against gas." Indeed, we were absolutely unprepared, so much so, that after the German attack nearly every household in England contributed to our first inefficient and improvised mask. Is not this suggestion of our preparation a deliberate attempt to deceive the German public? They seem to have been as easily hoodwinked on gas questions as on many others.

Germany Prompted by Production Monopoly.—An important point arises. The Germans failed to exploit their initial success. This is not very surprising. Whatever the opinion of the chemists behind the movement, the German General Staff must have retained the elements of precaution in its opinion. It could not have taken for granted the formidable success which the chemists proved justified in prophesying. This being so, we can fairly assume that had there been very serious difficulties in carrying out this huge war experiment it might never have materialised. Such difficulties might have been found in production. But as we have seen, the question of production was the most easily forged link in the chain of events which led to the use of poison gas by Germany. In other words, this monopoly in ease of production was an inducement to the Germans to proceed with their experiment.

The earliest German cloud gas attacks established beyond a doubt the enormous value of gas against unprotected troops, in other words, its value as a complete surprise. These conditions were again approached in the first German use of mustard gas. The most telling examples will probably be found in the future, unless the correct precautions are taken. The whole history of chemical warfare during the war was a struggle for this initiative, a struggle between gas protection and aggression.

Standard Uses for Gas;—Gas Shell.—But gas found an important use besides that of strategic surprise. It became a standard weapon for certain clear and definite tactical purposes. (For some of these, indeed, the factor of local surprise was important.) We refer to the specific use of gas shell for the neutralisation of batteries, roads, and areas, and to the use of cloud gas, prior to offensives for the production of casualties, and wearing down of reserves. The Ypres attack had not by any means established the use of gas for such purposes. There is no doubt that, from this point of view, the experimental period carried on for many months. Naturally, in some respects, there was always an experimental element in the use of gas.

Further German Cloud Attacks.—Two days after the first cloud gas attack the Germans launched a second against the Canadians, with similar results. Quoting from official despatches: "On the early morning of the 24th a violent outburst of gas against nearly the whole front was varied by heavy shell fire, and a most determined attack was delivered against our position east of Ypres. The real attack commenced at 2.45 a.m. A large proportion of the men were asleep, and the attack was too sudden to give them time to put on their respirators." These latter were hurriedly improvised after the first Ypres attack.

Hill 60.—Four more attacks occurred in May, notably in the region of Hill 60. "On May 1st another attempt to recapture Hill 60 was supported by great volumes of asphyxiating gas which caused nearly all the men along a front of about 400 yards to be immediately struck down by its fumes." "A second and more severe gas attack under much more favourable weather conditions enabled the enemy to recapture this position on May 5th. The enemy owes his success in this last attack entirely to the use of asphyxiating gas." "It was only a few days later that the means which have since proved so effective of counteracting these methods of making war were put into practice." (Official despatches, 1915.) The despatch further described how violent bombardments, the confusion and demoralisation from the first great gas surprise, and subsequent almost daily gas attacks, prevented the proper reorganisation of the line in question.

Origin of German Gas Shell.—After May a long period elapsed during which the Germans confined their war chemical activities on the front to the use of gas shell. Schwarte's book describes their origin as follows:—"The main idea which influenced the FIRST construction of a German projectile containing chemicals (October, 1914) was that of adding to the charge an irritant substance, which would be pulverised by the explosion of the projectile, and would overwhelm the enemy with a cloud of dust. This cloud would hover in the air and have such an effect upon the mucous membranes that, for the time being, the enemy would be unable to fight in such an atmosphere. By altering the construction of the 10.5 c.m. universal shell for light field howitzers, the `N.i' projectile was created in the form of 10.5 c.m. shrapnel, the bullets of which were embedded in a sternutatory powder (double salts of dianisidine) well stamped down, instead of an explosive. By means of the propelling charge and the grinding effect of the bullets, this powder was pulverised on explosion. The irritation caused was not very intense, lasted only a short, time and affected only a limited area and therefore it was of no importance in the field, but the initial step had been taken. Liquid irritants soon came to the front—xylyl bromide and xylylene dibromide—a mixture used later under the name of T. stuff, bromo-acetone and brominated methyl ethyl ketone, later introduced under the name of B. stuff and Bn. stuff."

During experiments they gave such improved results in intensity, in power of lasting and of affecting an increased area, that practical results in the field were ensured. The use of these liquids in projectiles, however, was contrary to the accepted idea with regard to artillery, according to which liquid materials should not be used for ballistic reasons. Specially arranged shoots were required to prove that the projectiles in use in the German Army could also be used from the ballistic point of view when filled with liquids.

In this way the first effective German gas projectile, the T. shell for heavy field howitzers, was evolved (January, 1915).

Early German Gas Shell.—The first important use of German gas in shell was that of brominated and chlorinated organic compounds, T. and K. stuffs. Schwarte's book tells us "the use of these projectiles was continually hampered by lack of understanding on the part of the troops which it was difficult to overcome. In the summer of 1915 it was practically in the Argonne alone that any considerable results were attained by the new projectiles." And he describes how the first elements of the new gas tactics were developed there.

A Successful Experiment.—The development of the gas shell, the use of which, generally speaking, is independent of, but co-ordinated with, wind direction, may have received stimulus from the fact that the prevailing wind, so important for cloud gas, favoured the Allies. It is clear that this