152 THE NEW WORLD OF SCIENCE 



these will indicate the possibilities of the organization when it 

 was forced to discontinue its activities on November n, 1918. 



The Development of Chemical Warfare. We have traced 

 the organization of the Chemical Warfare Service and have 

 seen that it grew to meet the ever increasing demands of gas 

 warfare. Let us now examine briefly the development of 

 chemical warfare itself. 



Chlorine was first used in chemical warfare, both because it 

 was a commercial product and readily accessible and because 

 it was a nearly ideal gas for a cylinder attack. For this pur- 

 pose a gas had to be easily compressible, heavier than air, and 

 with a boiling point sufficiently low to cause it to volatilize 

 easily and rapidly ; it had to be toxic in relatively low concen- 

 trations in air and it should be rather stable toward other 

 chemical agents. In all but the last respect, chlorine fulfilled 

 all these requirements. For months before the first gas attack 

 on April 22, 1915, the Germans must have been busy, building 

 up a supply of chlorine, developing a gas cylinder, providing 

 a mask to protect their own troops and in training the 

 " Pioneers," the men who were in charge of the actual gas 

 attacks. We are all acquainted with the success of that first 

 attack, and only the German's lack of faith in his own weapon 

 prevented him from a clear sweep of Calais and England. 

 About December, 1915, phosgene was mixed with the chlorine. 

 This added a greater toxic value to the gas mixture and intro- 

 duced a second very valuable property, namely, the delayed 

 action of the phosgene. Men might go for twelve hours after 

 being gassed with phosgene before realizing the fact, and then 

 only became aware of it, when, on slight exertion, they dropped 

 from heart disorder. 



The cylinder attack had very decided disadvantages and the 

 German soon learned that he could accomplish the same end 

 with a much greater degree of safety by using the poison gas 

 in shell. Indeed, gas shell, containing lachrymatory (tear pro- 

 ducing) gases, were used almost simultaneously with the first 

 cylinder attack. The first toxic gas to be used was superpalite, 



