RECENT PROGRESS IN CHEMISTRY. 535 



chiefly nitrocompounds, much work is done of a purely scientific 

 nature, such as investigations on the chemical reactions and products 

 of explosive mixtures, on the heat disengaged by their explosion, on 

 the pressure of the gases produced, and on the duration of the ex- 

 plosive reaction. Thanks to the " Notes " of Professor C. E. Munroe, 

 of the United States Naval Academy, chemists are informed of the 

 freshest novelties in this department, rendering further mention su- 

 perfluous. 



The researches of chemists in the aromatic series outweigh in both 

 number and importance those in all other sections. The once despised 

 refuse coal-tar has created an entirely new chemistry, and, in its prod- 

 ucts and derivatives, is by far the most promising field for investiga- 

 tors. The compounds of the aromatic series have afforded some of 

 the most notable successes in synthetical chemistry, as well as some of 

 the most useful substances for dyeing, for hygienic and medicinal 

 purposes. The oil obtained in the dry distillation of bones, a subject 

 of classic investigations by Anderson, of Glasgow, forty years ago, 

 has recently acquired new interest ; one of its constituents, pyridine 

 (C 6 H 6 N), has been obtained in several ways which show that it bears 

 the same relation to certain acids derived from natural alkaloids, such 

 as quinine, nicotine, etc., that benzene does to benzoic and phthalic 

 acids. These facts point to the possible artificial preparation of qui- 

 nine at no distant day. This view of the constitution of the alkaloids 

 is confirmed in many ways, notably by Ladenburg's discovery that 

 piperidine, a base occurring in pepper, is hexahydrobenzene. 



Professional chemists also acknowledge the marvelous success in 

 unraveling the complications of isomerism, and the important aid 

 afforded the study of isomeric bodies of the aromatic group by the 

 doctrine of orientation. These rather technical details can receive, 

 however, but brief mention, though a whole series of lectures could be 

 devoted to the fascinating topic. Leopold Gmelin, when writing his 

 "Hand-book of Chemistry," in 1827, requested organic chemists to 

 stop making discoveries, or else he could never finish ! And during 

 the sixty years which have elapsed the activity in organic chemistry 

 has been unceasing ; yet the extraordinary number of facts now known 

 is not so great as those which the prophetic eye sees disclosed by 

 recently revealed lines of investigation. 



The crowning glory of chemistry is the power of producing, in the 

 laboratory, from inorganic matter, substances identical with those ex- 

 isting in the vegetable and animal kingdoms. Belief in the mysterious 

 vital force operating in living beings received a rude shock at the 

 hands of Wohler, sixty years ago, and successive triumphs in synthesis 

 have dispelled it entirely, so far as non-organized bodies are con- 

 cerned : " To-day we know that the same chemical laws rule animate 

 and inanimate nature, and that any definite compound produced in the 

 former can be prepared by synthesis as soon as its chemical constitu- 



