CHEMISTRY. 



213 



nitrogen the water at the moment of evapor- 

 ation appearing to be in a condition favoring 

 such union. Schonbein thinks that in all cases 

 of generation of nitrites during combustion of 

 various bodies, the combustion is only the in- 

 cident, evaporation being the true cause. In 

 a more recent note on this subject, Prof. Hunt 

 questions -whether the results arrived at by 

 Schonbein can be ascribed to evaporation, ex- 

 cept in so far as the cooperation of water, and 

 a slightly elevated temperature, are necessary 

 conditions of the reaction. 



But since evaporation of water is continually 

 going on in the atmosphere, it will follow that 

 the generation of nitrite of ammonia must be 

 an equally constant phenomenon. When this 

 salt is brought in contact with fixed bases, as 

 potash, soda, lime, these respectively enter into 

 union with the acid, the ammonia being set 

 free ; and the gradual oxidation of these fixed 

 nitrites, converting them into the correspond- 

 ing nitrates, is a result then readily admitted. 

 In rainy countries, like our own, the nitrates 

 that would accumulate in the soil are washed 

 away as formed, disappearing through springs 

 and rivers in the ocean. But in hot countries, 

 which have a dry season of several months' du- 

 ration, and where in many cases there pre-exist 

 vast plains of alkaline earth, the resulting ni- 

 trates accumulate. The old theory of produc- 

 tion from decaying organic matters is disproved 

 by such marked instances as those of the nitre- 

 beds of Bengal, and it may be added, of Ata- 

 cama, where no suflicient supply of organic sub- 

 stances exists or can collect. 



The new facts have, if possible, a yet more 

 important bearing on vegetable physiology. 

 Liebig long since made the bold assertion that 

 no plant needs any artificial supply of ammonia 

 or of matters capable of yielding it. enough of 

 this nutriment being furnished, as he thought, 

 by natural means. Whether this assertion was 

 or was not too sweeping, Schonbein's discovery 

 goes far in support of it. Plants cannot as- 

 similate free nitrogen. But it is a well-known 

 fact that all plants, during seasons of growth, 

 are exhaling or evaporating water in abundance 

 from their leaves ; while it is through pores in 

 the leaves at the same time that they mainly 

 inhale or receive the carbonic acid and other 

 compound gases, among them ammonia and ni- 

 trous acid, from which their supplies of organic 

 matter are continually generated. 



Accordingly, if the new facts and theory be, 

 as now appears, established, a very important 

 step is gained in showing that every growing 

 plant supplies by evaporation the conditions for 

 the generation of certain inorganic gaseous 

 compounds indispensable to its own nutrition, 

 and that at the very points where such mate- 

 rials are required for appropriation, namely, at 

 the porous surfaces of the leaves. 



V. SYNTHESES OF ORGANIC SUBSTANCES. The 

 opinion that substances naturally of organic 

 origin, or directly derivable from such, as for 

 example, sugar, albumen, urea, common al- 



cohol, <fcc., could only result through prior 

 agency of living bodies, and in no case by 

 direct union of their elements (artificial syn- 

 thesis), took firm hold of the minds of most 

 chemists during the earlier development of the 

 organic department of the science. The first 

 fact in contradiction of this belief, was the 

 production by Wohler of urea from its ele- 

 ments, that is, from inorganic compounds ob- 

 tained in the ordinary ways from such ele- 

 ments, in 1828. Thus, he found that physical- 

 ly as well as chemically urea is identical with 

 cyanate of ammonia (C 2 H 4 K" 2 O 3 = NH 4 O 

 f Cu XO). Since the date just given, the num- 

 ber of syntheses of organic substances has 

 become quite considerable ; and some of them 

 are highly important. Through the researches 

 ' of Perkin and Duppa, and of M. Kekule, the 

 chemist is now enabled to build up step by step 

 from their elements three highly complex or- 

 ganic acids, the succinic, paratartaric, and malic. 

 Mr. M. Simpson (" Philos. Mag." vol. xxiii, p. 

 327, 1862) gives an improvement of his previous 

 process for producing succinic acid, by employ- 

 ment of bromide of ethylene (C 4 H 4 Br 2 ), and 

 which yields the acid directly and in a state of 

 purity. In the same journal and volume, is an 

 account of the first synthesis of a substance 

 possessing saccharine qualities, by Boutlerow, 

 by action of lime water on a solution of di- 

 oxymethylene. 



Alcohol, &c. In the French department of 

 the London Exhibition, of 1862, could be seen 

 a bottle of alcohol, differing in no respect of 

 taste, odor, or other qualities, or of composition, 

 from ordinary alcohol, save in the mode of its 

 origin being a product of chemical synthesis, 

 accomplished by M. Berthelot. He first as- 

 certained that olefiant gas (C 4 H 4 ), agitated 

 with many thousand concussions with sulphuric 

 acid (SO 3 , HO), combining with two equiva- 

 lents of the latter, produced sulphethylic acid 

 (C 4 H s O, SO, + HO, SO,). When this acid 

 is heated with water, common or vinic alcohol 

 results, distilling over, and leaving sulphuric 

 acid behind. But if any other substance ho- 

 mologous with (C 4 H 4 ) be substituted, the cor- 

 responding alcohol, as the amylic, &c., is pro- 

 duced. It is claimed that while Berthelot's 

 first mention of this method to the French 

 Academy dates Jan. 1855, the Sieur Castex had 

 in the preceding December taken out a patent 

 for producing alcohol by absorbing smoke from 

 burning organic matter in concentrated sul- 

 phuric acid, mingling with water and distil- 

 ling. 



Berthelot's more recent method, however, 

 breaks down yet more strikingly the distinction 

 between inorganic and organic chemistry. Ace- 

 tylene (C 4 H 3 ) is known as one of the simplest 

 and most permanent of the hydrocarbons. 

 It was formerly obtained from olefiant gas, 

 by action of the electric spark, or other- 

 wise. Berthelot has now succeeded, first, in 

 producing acetylene by synthesis. Carbon is 

 first highly purified, as by action of chlorine 



