292 



SCIENCE. 



[N. S. Vol. II. No. 36. 



two new bases paraniline and paramido- 

 phenol.* Other products from the same 

 residues enabled the great investigator to 

 arrive at a knowledge of the mode of forma- 

 tion and structure of rosaniline. Later 

 another French color-maker sent Hoffmann 

 a well crystallized by-product which he re- 

 cognized as meta-toluylendiamine which he, 

 together with Muspratt, had endeavored to 

 make by synthesis. He found it to have 

 been undoubtedly produced by the Bechamp 

 method from nitrobenzene contaminated 

 with dinitrotoluene. 



In his most interesting and valuable ad- 

 dress, from which manj^ of these illustra- 

 trations have been obtained, Caro calls at- 

 tention to other instances of contributions 

 to the advancement of science from this 

 great industry ; the use of zinc dust in 

 strongly alkaline solution for the reduction 

 of nitro-bodies was worked out in the fac- 

 tories ; safranine was produced technically 

 several years before its structure and mode 

 of formation were made out hy ISTietzki. 

 The empirical formation of nitrodracylic 

 acid and /3 naphthylamine is cited as fur- 

 nishing contributions to the establishment 

 of isomerism in the classes to which they 

 respectively belong. Aniline blue, pro- 

 duced empirically by heating together fuch- 

 sine and aniline, was found later by Hoff- 

 mann to be triphenylated rasanilinf and led 

 him to the recognition that change of color 

 could be produced by substituting an alkyl, 

 phenyl or benzjd radical for hydrogen ; and 

 so started the theory, now developed into 

 a law, that color of compounds is a func- 

 tion of structure, and that, in those com- 

 pounds, having antifermentive, therapeutic 

 or toxic action, the influence will vary in 

 intensity with the position of the radical 

 in the molecule. Thus it has been found 

 that ortho-cresol is less active as an anti- 

 ferment than the meta-compound , wliile this 



* Proc. Roy. Soc. 1863. 31-2. 

 t Proo. Roy. See. 13. 9. 



in turn is less intense in its action than para- 

 cresol. a Naphthol is more poisonous and 

 more actively antiseptic than /3 naphthol. 



The field of chemical work, here so won- 

 derfully opened up, has done much to bring 

 into closer contact and communion the pro- 

 fessional men and investigators on the one 

 hand and the practical technologists on the 

 other. Professional men find that such 

 union furnishes valuable material for study 

 and most useful suggestions for work. As 

 Hoffmann says, " the technologist is not 

 likely to leave long without utilization any 

 fact of science which may be developed and 

 made valuable from the technical side;" 

 so we find that the benefits which flow from 

 each to each are rapidly increasing from 

 year to year and the distinction formerly 

 made between science and technology is 

 rapidly being broken down, and more 

 cordial, and therefore more useful, relations 

 established. Such union for progressive 

 work was established with profit to both 

 sides by Hoftmann and ISTicholson, Graebe 

 and Caro, 0. Fischer and E. Heppe and 

 others, and the example of these authorities 

 has been followed by the great manufac- 

 turers in all countries by the foundation in 

 the works, of well-equipped laboratories, in- 

 tended not only for control of processes by 

 analytical methods, but for the improve- 

 ment and extension of processes by careful 

 research methods and the discovery of new 

 principles. Ostwald* has clearly set forth 

 the manner in which technology and science 

 may work together in electrical work, in 

 the various directions. 



How rapidly this practice has grown will 

 be illustrated by the fact that the great 

 works, successors to Meister, Lucius and 

 Bruning at Hochst, made, in 1S90, from 

 1700 to 1800 colorsf and employ 3000 per- 



*Chemische Industrie. 1895. 212. From Zeit- 

 sclirift fiir Electroteohnik und Electrochemie. 1894. 

 81. 



t Ost. Lclirbiich der Teclmischen Clieraie. 



