ORGANIC CHEMICAL INDUSTRY — STINE 189 



freezing point of dynamite. This work led me to a study of various 

 nitro derivatives of xylene and other hydrocarbons. Work on the 

 nitration of hydrocarbons and other organic compounds in turn led 

 to the preliminary work on the production of dye intermediates. In 

 connection with my w^ork on low-freezing dynamites, for example, a 

 method was worked out and equipment designed for separating the 

 isomeric di-nitro toluenes, and this method was later employed in 

 making 2:4 dinitrotoluene as an intermediate in the manufacture 

 of dyes. 



Still another early assignment was an investigation of permissible 

 explosives for use in mines, and in the early days I did all of the 

 work myself connected with the examination of the safety properties 

 of such permissible explosives as were then available, attending per- 

 sonally to the testing of these explosives by the Bureau of Mines at 

 the Pittsburgh Testing Station, which, incidentally, had just been 

 opened. The study of the properties of these permissible explosives 

 from the point of view of their tendency to ignite coal dust mixed 

 with air, or to explode mixtures of gas and air, led to the development 

 of a wholly new series of permissible explosives, very much safer for 

 use in gaseous mines than the earlier so-called permissible explosives. 



Many interesting incidents, a few of them amusing, come to mind 

 as I think of other phases of this early work on explosives, including 

 the manufacture of TNT, tetryl (trinitrophenylmethyl nitramine) 

 and picric acid, but in each and every case the story would be the 

 same — namely, a dependence upon the products and the techniques 

 of organic chemistry. 



To the ancient industry of agriculture, the organic chemical in- 

 dustry has made many notable contributions. In connection with 

 plastics, mention was made of urea, which today sells for less than 

 one-tenth of its price in 1920. This synthetic nitrogenous chemical 

 not only finds wide application in plastics, but also as a fertilizer 

 ingredient. Mention should also be made of the organic mercurials 

 which are being used so successfully for the control of various plant 

 diseases caused by fungi, and the long-chain alkyl rliodanates for 

 combating the ravages of sucking insects on certain agricultural 

 crops. 



In this connection mention should also be made of recent work 

 at the Boyce Thompson Institute for Plant Research with organic 

 compounds which modify the growth of plants. Among the more 

 interesting of these materials are compounds such as indole butyric 

 acid, which promote root growth even on the stems and leaves of 

 plants to which they are applied. These so-called plant hormones, 

 which are used in concentrations as low as 1 part in 40,000, bid 

 fair to find wide practical application in agriculture, horticulture, 

 and floriculture for starting cuttings of plants difficult to root. 



