84 



CHEMISTKY. 



with water containing a little unheated soil, 

 the production of nitric acid begins again. 

 The theory has been subjected to practical 

 tests in England, and the results, as stated in 

 "Nature" by Mr. R. Warington, are as fol- 

 lows: 



It was found that the vapor of bisulphide of carbon, 

 and of chloroform, effectually prevented nitrification 

 in a moist garden soil through which air was fre- 

 quently aspirated, while without these vapors the 

 soil produced nitrates in considerable quantity. A 

 solution of chloride of ammonium containing a little 

 tartaric acid, phosphate of potassium, and carbonate 

 of calcium, was also completely nitrified in a few- 

 weeks by the addition of a small quantity of soil 

 taken from the " fairy-ring " of a meadow. This so- 

 lution, when nitrified, was successfully used as seed 

 to produce nitrification in other similar solutions, 

 which without this addition produced no nitric acid. 

 It was further shown that light was prejudicial to 

 nitrification ; solutions kept in a dark cupboard pro- 

 ducing nitric acid, while similar solutions standing 

 in daylight produced none. The evidence has thus 

 become very strong that the nitrates in soil owe their 

 origin to oxidation brought about by living organ- 

 isms. That mycodermsj in their processes of life, 

 may exert a powerful oxidizing action upon organic 

 matter, we have already learned through the re- 



, searches of Pasteur and others. The most familiar 

 example is that of the acetic fermentation. Vinegar 

 is produced by the oxidation of alcohol during the 

 growth of a very simple organism, the Mycoderma 

 aceti; without the growth of such an organism no 

 vinegar is ever formed. It is by similar low organ- 

 isms that fermentation of all kinds is brought about. 

 Putrefaction has also been shown to be equally de- 

 pendent on the presence of microscopic organisms, 

 and except under the conditions suitable for their 

 rapid development putrefaction will not take place. 

 W ith this abundant evidence before us of the ener- 

 getic decomposition of organic matter brought about 

 by what we may term microscopic fungi, we can 

 hardly be astonished to find that the same agency is 

 capable of oxidizing the nitrogen of organic matter 

 and of ammonia, and thus producing nitric acid. 

 The organisms which produce these wonderful 

 changes consist of colorless cells ; they are indepen- 

 dent of daylight, for they derive their supply of car- 

 bon exclusively from organized matter, and from the 

 decomposition of such matter they obtain the force 

 necessary for life and growth. In these respects 

 they differ entirely from green vegetation, in which 

 sunlight is the source of all energy, and carbonic-acid 

 gas ? decomposed by the aid ot'light, the material from 

 which carbon is derived. The colorless and green 

 organisms, however, equally require phosphoric acid, 

 potash, and other ash constituents ; and both appear 

 to be capable of assimilating nitrogen in the form of 



.ammonia. Not only are these simple organisms inde- 

 pendent of the aid of light, but light is, in some cases 

 ut least, actually fatal to their existence. This fact 

 has quite recently been established by Downes and 

 Blunt. They find that the bacteria present in an or- 

 ganic fluid mav in many cases be entirely destroyed by 

 exposure of the solution to daylight, and that even 

 when this is not the case their development is much 

 retarded by such treatment. This observation is per- 

 fectly in accordance with the fact observed at Kotham- 

 Bted, that nitrification did not proceed in solutions 

 exposed to daylight. In the last communication of 

 Schloesing and Mtintz, it is stated that vegetable soil 

 suspended in water, by passing a stream of air 

 through the mixture, undergoes nitrification both in 

 light and darkness. No details of the experiment are 

 given, but it seems probable that such a mixture 

 would be more or less opaque, and the greater bulk 

 of the material consequently at all times in partial 

 darkness. The microscopic organism producing ni- 



trification has probably distinctive characters, and 

 might be isolated by cultivation under conditions 

 specially suitable to its growth, but more or less un- 

 favorable to the life of other associated germs. Pas- 

 teur has pursued this method with success in the 

 case of beer yeast, and has shown that with the pure 

 yeast thus obtained an unchangeable beer may be 

 manufactured, the organisms producing secondary 

 changes having been excluded. The subject of ni- 

 trification has clearly reached a stage which demands 

 the aid of the vegetable physiologist. 



New Compounds from Carbon BisulpJiuret. 

 It is known that carbon bisulphuret, like cyan- 

 ogen, will unite directly with metals without 

 the intervention of oxygen or any similar body ; 

 hence its distinguishing name of " erythrogen." 

 Guided by this property, L. Thompson made 

 the attempt to discover whether erythrogen 

 could displace cyanogen from any of its com- 

 binations, and in this way discovered not only 

 that cyanogen can be so displaced, but also that 

 in so doing two hitherto unknown compounds 

 are produced, viz., a new pigment and a new 

 explosive. The first experiment was made with 

 a sample of coal-gas containing a rather large 



Eroportion of carbon bisulphuret. A set of 

 iebig bulbs were charged with caustic-potash 

 solution containing dissolved bicyanide of mer- 

 cury, and the coal-gas was then slowly passed 

 through the bulbs, with the following results : 

 Very soon the solution became milky, and this 

 effect continued to increase for several days, 

 with deposition of a white precipitate, which 

 became successively first gray, then black, and 

 finally a beautiful scarlet, thus proving the ex- 

 istence of at least two, perhaps three different 

 compounds. Having ascertained by analysis 

 that the scarlet compound derived nothing 

 from the coal-gas but the bisulphuret of car- 

 bon, the gas was abandoned, and pure bisul- 

 phuret of carbon was employed instead. The 

 process is as follows : 



A strong solution of the cyanide of potassium is 

 to be boiled for several minutes upon binoxide of 

 mercury, or, what answers equally well, the nitric 

 oxide of mercury sold by apothecaries ; it is then 

 to be mixed with three times its bulk of a very strong 

 solution of caustic potash, and when it has become 

 cold it must be cautiously decanted into a Florence 

 flask or other convenient vessel, and a considerable 

 quantity of bisulphuret of carbon added to it with 

 frequent agitation. The mixture assumes in rapid 

 succession a variety of tints, passing from white, 

 yellow, brown, and gray, into black ; and, if then 

 left to the ordinary temperature of the atmosphere, 

 the black is changed into scarlet in the course of 

 twenty-four to forty-eight hours, according to the 

 quantity of caustic potash present. The larger the 

 amount of potash, the shorter is the time required 

 for the development of the scarlet color ; but this 

 change is very soon brought about by the employ- 

 ment of heat,'and therefore the flask containing the 

 mixture should be placed in a water-bath at 1108 

 Fahr., when in about half an hour the scarlet pre- 

 cipitate will have formed, and we may distill off 

 and collect the surplus bisulphuret of carbon, after 

 which the pigment must be well washed and care- 

 fully dried. 



This pigment (ponsceliori) is a scarlet powder 

 of a very brilliant tiait. It rivals gold itself in 

 resisting the effect of atmospheric influences, 



