166 THE NEW WORLD OF SCIENCE 



of preparing methyl dichloroarsine, which is a more satisfactory 

 substance. The Chemical Warfare Service was successful in 

 its efforts to develop methods for preparing both of these 

 substances. 



Methyl dichloroarsine can be made in three stages: Sodium 

 arsenite is prepared by dissolving arsenic trioxide in caustic 

 soda solution; the action of dimethyl sulfate at 85 yields 

 disodium methyl arsenite, Na 2 CH 3 AsO 3 . Upon passing sulfur 

 dioxide through the solution, methyl arsine oxide results. This 

 is then converted into the chloride by passing hydrogen chloride 

 (gas) into the mixture, and the chloride is distilled and con- 

 densed. 



Lachrymators also received a great deal of attention. The 

 French method for the preparation of brombenzyl cyanide, 

 which is probably the best lachrymator used on the field (though 

 more satisfactory ones were developed and would have been 

 used during 1919 had the war continued) was improved and 

 placed on a manufacturing basis. 



A large number of other compounds were studied, many of 

 which were discarded as useless while others were developed 

 to the point where they could have been placed in large scale 

 production had the need manifested itself. 



INORGANIC RESEARCH 



Inorganic chemistry does not offer as many interesting prob- 

 lems nor as spectacular ones as does organic chemistry. 

 Among the problems successfully solved were the large scale 

 production of hydrocyanic acid (the method for which was 

 later used technically for its manufacture as an insecticide), 

 arsenic trichloride, nitrogen peroxide, arsine and fluorine. 

 Fluorine may be obtained very satisfactorily by electrolysis of 

 a fused bath of acid potassium fluoride at 22$-2$o C. in a 

 copper containing vessel, using a graphite anode. It is prob- 

 able that better results could be obtained by the use of a 

 graphite anode, graphite diaphragm and a graphite containing 

 vessel, the last serving as a cathode. Various derivatives, such 



