CHEMISTRY. 



177 



prepared the way for Schonbein's results, if 

 not indeed to have anticipated them. 



Schonbein's experiments have appeared to 

 show that during combustion in air of charcoal, 

 fats, illuminating gases, wood, coal, and phos- 

 phorus, nitrite of ammonia is incidentally gen- 

 erated in determinable quantities ; and at least 

 ammonia, during slow combustion in air of ar- 

 senic, at 200. 



Prof. Bottger, of Frankfort, has more recent- 

 ly published a reclamation, believing himself to 

 have been the first to show by experiment, and 

 to announce, that in every act of combustion in 

 air nitrite of ammonia is formed. (Pogg. Ann., 

 cxvii, 1Y5.) 



M. J. Nickles ("Amer. Jour, of Science," 

 March, 1863) is struck with what he considers 

 a recent change in the results of Schonbein's 

 labors in that, where he once recognized only 

 ozone, he appears now to discover only nitrous 

 oxide or nitrite of ammonia. To the test com- 

 monly employed by Schonbein and others to 

 determine the presence of these compounds 

 namely, starch-paste, to which iodide of po- 

 tassium, and sometimes a very little dilute 

 sulphuric acid is added he objects that the 

 blue coloration of the starch relied on as the 

 test in the case, may no less take place from 

 the presence of ozone, of chlorine, bromine, or 

 iodine, of aqua-regia, or hypochlorous or Jiypo- 

 'bromous acid. He is led to conclude, also, that 

 the general theory of formation of nitrites in 

 air was substantially anticipated both by Prof. 

 T. S. Hunt, of Montreal, and by Prof. Bottger. 

 But he credits to Schonbein alone the obser- 

 vation of the apparent fact perhaps yet to bo 

 found of the first importance in connection 

 with vegetable physiology and with the science 

 of agriculture that the generation of nitrite 

 of ammonia goes on at the very surface of 

 the leaves of plants from which water is evap- 

 orating, and as a simple and necessary conse- 

 quence of the evaporation itself. (See PHYSIOL- 

 OGY.) 



Prof. Hunt, in a letter to the editors of the 

 journal last quoted (same number), says : " My 

 object is to claim for myself the new theory of 

 nitrification, which Schonbein seeks to found 

 upon his recent experiments, and which I pub- 

 lished nearly two years since. It is in reality 

 but a natural deduction from my view of the 

 double nature of nitrogen as the nitryl of ni- 

 trous acid [presented under ALLOTROPIO STATES, 

 preceding volume; and which the author re- 

 peats in his communication], which I have main- 

 tained since 1848." It does not appear, how- 

 ever, that Prof. Hunt made explicitly a deduc- 

 tion of the nitrite-theory as it now stands, how- 

 ever naturally it might flow from his actual 

 observations at the time. 



Dr. G-. 0. Schaeffer, in a letter through the 

 same medium (May) claims to have put forth, 

 through Dr. Craig's " Report on Nitrification " 

 (really presented in 1856, although published 

 in 1861), a "hypothesis * * * arrived at by 

 legitimate analogies, and which it would be in- 

 VOL. iu. 12 A 



teresting to test by experimental investiga- 

 tions," and which, "based upon that general 

 chemical action by which various bodies assume 

 the elements of water in such a way as to pro- 

 duce salts of ammonia," claims that this prin- 

 ciple may be exemplified in the case of atmos- 

 pheric nitrogen, the latter assuming 4 equiva- 

 lents of water, and thus giving a nitrite of that 

 alkali. Further, he believes himself to have 

 made the first announcement, in a paper ap- 

 pearing in the " Proc. of the Amer. Assoc. for 

 Adv. of Science," 1850, of such a fact as that 

 the rainwater collected after a period of fre- 

 quent and severe thunder showers contained 

 of itself so much of nitrates and nitrites, as to be 

 unfitted for use in certain tests for these com- 

 pounds which he was then making. 



Meanwhile, the subject is further complicat- 

 ed, if indeed the theory be not in some degree 

 unsettled, by the recently published researches 

 of E. Bohlig (Ann. der Chem. und Pharm., 

 cxxv, 21-33), and which he states that he has 

 for some time been carrying on, independently 

 of the investigations of Bottger and Schonbein. 

 He is lead to believe that the atmosphere at all 

 times contains in greater or less proportion the 

 nitrite of ammonia, but never the nitrate, the 

 former being originated " wherever ozone comes 

 in contact with nitrogen [and water-vapor, of 

 course], as well as in all cases of combustion in 

 free air." He does not admit Schonbein's view 

 of a direct union of nitrogen and water attend- 

 ing evaporation ; but he concludes that in such 

 case the water-vapor forming merely collects 

 the preexisting nitrite from the atmosphere. 

 He holds that Schonbein's experiments are vi- 

 tiated by the facts of their being made with un- 

 limited quantities of air, and of his having over- 

 looked the preexistence of nitrite in the air. In 

 some of Bohlig's experiments on rain-water, as 

 after a protracted rain, the water required to 

 be evaporated to ^th its original bulk before 

 giving evidence of nitrous acid ; at other times, 

 when the weather was fine, the water often 

 gave the reaction after once flowing over the 

 test-paper, and when its quantity was yet 

 scarcely diminished by evaporation. Again, 

 allowing carbonate of potash to deliquesce in 

 the air, the liquid salt then showed that it con- 

 tained also nitrite of ammonia : would Schonbein 

 affirm that water, in the act of condensation, also 

 unites with nitrogen, and generates the nitrite? 



In concluding his abstract of these researches, 

 Prof. S. "W. Johnson, of Yale College, remarks 

 that the whole subject requires thorough ex- 

 perimental revision. And although some of 

 Schonbein's experiments can scarcely be ex- 

 plained on any other hypothesis, he thinks that 

 the facts in our possession are still not sufficient 

 to warrant the assumption that nitrite of am- 

 monia is spontaneously formed in the air from 

 nitrogen and the elements of water. 



IV. ORGANIC COMPOUNDS. Under this head 

 will be included not only compounds which 

 are directly of organic origin, but also such as, 

 while resembling the former in composition and 



