INDUSTRIAL PROGRESS DURING THE YEAR 1873. xli 



ordinary readers. Grimshaw's study of etbyl-amyl, Liebeii 

 and Rossi's work upon butyl compounds, and Cahours' re- 

 searches among the compounds of propyl deserve special no- 

 tice. Cahours in particular has obtained striking results, 

 having examined, besides many other bodies, comj^ounds of 

 propyl with sulphur, boron, silicon, mercury, zinc, tin, alu- 

 minum, and glucinum. Griinzweig's investigation of butyric 

 acid, and the labors of Pierre and Puchot upon the same sub- 

 stance, and upon propionic acid also, must not be overlook- 

 ed. Pierre and Puchot in their work have obtained results 

 of great interest in connection with the law of boiling-points ; 

 showing that the constant differences commonly supposed to 

 exist between the boiling-points of homologous substances 

 are not always to be depended upon. Several new organic 

 compounds containing silicon have been obtained, Troost 

 and Hautefeuille (who seem always to work together), and 

 Ladenburg, being the chief explorers in this direction. The 

 ground thus far covered in the study of these compounds 

 has been well described by Dr. Emerson Reynolds, who de- 

 livered before the Royal Institution a lecture upon "Alcohols 

 from Flint and Quartz." The lecturer, after pointing out 

 the striking similarities between silicon and carbon by them- 

 selves, showed that the same resemblances extended even to 

 their compounds, describing the most important among those 

 tlius far discovered. He also announced that he had succeed- 

 ed in obtaining the silicon analogue of cyanogen, a compound 

 which awaits further investigjation. 



In other departments of organic chemistry, Mayer and 

 Wright have well studied some of the derivatives of mor- 

 phine. Doubtless, in a very few years, we shall be able to 

 produce artificially not only tliis valuable alkaloid, but also 

 others, such as quinine, caffeine, etc. Hlasiwetz and Haber- 

 mann have continued their researches upon the proteine com- 

 pounds, obtaining results of some interest concerning caseine. 

 But the most bulky Avork of the year in organic chemistry 

 has been among the so-called aromatic compounds'. Unfoi'- 

 tunately, however, many of the German workers in this field 

 seem to have a mania for obtaining new compounds, and then 

 leaving them very imperfectly described. In consequence, 

 much of their work will have to be done over acrain. In this 

 group of compounds, isomeric bodies have already been mul- 



