CHEMISTRY. (AGKICULTURH.) 



157 



the last by solution or volatilization. Those of 

 the two remaining categories have not yet been 

 artificially reproduced. 



Horbaczewski has synthetically produced 

 uric acid by heating a mixture of glycocoll witli 

 ten times its weight of urea to a temperature 

 of from 200 to 230. After separation from 

 the resultant yellow, turbid, and pasty liquid, 

 and purification, a yellowish crystalline pow- 

 der was obtained, which possessed all the prop- 

 erties of uric acid. 



Notwithstanding the apparent success that 

 has attended many experiments in artificial 

 synthesis of organic compounds, it appears to 

 be still an open question whether the natural 

 substances are actually duplicated. Several of 

 the vegetable acids have the power of turning 

 the plane of polarized light either to the right 

 or left. Some similar substances have been 

 prepared artificially, and the products thus ob- 

 tained have been shown to have all the prop- 

 erties of the corresponding natural substances, 

 with the exception of the optical activity. The 

 conclusion has been drawn that artificially pre- 

 pared substances can not act upon polarized 

 light, and that in order to get an optically act- 

 ive substance we must have the intervention 

 of the life-process. Recently, however, Per- 

 kin and Dupra succeeded in making racemic 

 acid from bibrom-succinic acid, and Jungfleisch 

 and Pasteur showed that this artificially pre- 

 pared racemic acid could be split up into dex- 

 tro- and Ia3vo-tartaric acids. Thus the artificial 

 preparation of one optically active substance 

 was certainly accomplished, and some chemists 

 believed that the rule hitherto found prevailing 

 was broken. Pasteur reviewed the question 

 before the Paris Chemical Society in Decem- 

 ber, 1883, and reiterated his principle of the 

 existence of a fundamental difference between 

 vital and lifeless substances, which was defined 

 by their asymmetry or symmetry in optical 

 function, and of the impossibility of producing 

 an asymmetrical substance without the inter- 

 vention of life ; and he denied that it was dis- 

 turbed by Perkin and Dupra's synthesis of 

 racemic acid. On the contrary, he claimed 

 that the distinction was confirmed by his own 

 experiments and those which M. Jungfleisch 

 and M. Le Bel, who contradicted him, had per- 

 formed with it. 



Anschutz and Eltzbacker, experimenting on 

 the action of aluminum chloride upon tetra- 

 bromide acetylene dissolved in benzine, ob- 

 tained a hydrocarbon, hardly soluble in the 

 ordinary solvents, which, instead of the sub- 

 stance expected, proved to be anthracene. The 

 synthesis affords the first experimental evidence 

 for the assumption generally made that the 

 middle carbon elements in anthracene are di- 

 rectly united. 



Agricultural Chemistry. The Association of 

 Official Agricultural Chemists publishes the 

 processes it has adopted for the determination 

 of phosphoric acid in fertilizers. The water- 

 soluble phosphoric acid is first separated by 



washing out with water, and determined. The 

 citrate-insoluble phosphoric acid is then sepa- 

 rated, after washing the residue of the treat- 

 ment with water with strictly neutral amino- 

 nium-citrate solution, filtering, and treating the 

 filter and its contents with fuming hydrochloric 

 acid. The total phosphoric acid is then deter- 

 mined by successive treatments of the sub- 

 stance with solution of magnesium nitrate, 

 fuming hydrochloric acid, ammonium nitrate, 

 and molybdic solution, and magnesia mixture. 

 The sum of the water-soluble and citrate-in- 

 soluble subtracted from the total gives the ci- 

 trate-soluble. 



R. Warrington regards the experiments made 

 at Rothamsted during the last few years as al- 

 most decisive of the theory that nitrification is 

 produced by an organism. The process may 

 be started at will in any suitable solution by 

 the addition of a nitrified material, while with- 

 out this the solutions would remain sterile for 

 years. Phosphoric acid is essential to the con- 

 tinuance of the process, as it is to the existence 

 of life. The nitrifying organisms are found to 

 exist in the soil mainly within nine inches, 

 rarely to extend below eighteen inches, and 

 never, so far as the experiments show, below 

 three feet from the surface. The rate at which 

 nitrification proceeds depends also on the vig- 

 or of the organism. Organic carbon is neces- 

 sary only as it is required for the nourishment 

 of the organism, and excess is rather prejudi- 

 cial. Urine contains sufficient organic carbon 

 for its own nitrification ; but, since nitrification 

 is limited by excessive alkalinity of the medi- 

 um, strong urine is unfit for it. This fact has 

 an important bearing on the use of liquid ma- 

 nures. Experiments reported by E. Duclaux 

 also indicate that plants are incapable, without 

 the aid of microbes, of utilizing the organic 

 matters in the soil. 



Prof. F. H. Storer has described experiments 

 that he made to ascertain the importance of 

 the nitrogen constituents of the soil to plants 

 growing in it. He prepared four sets of five 

 jars each, and filled them variously with gar- 

 den-soil from which the organic matter had 

 been removed by calcination, Berkshire sand, 

 and vegetable loam from five different fields. 

 The jars were graduated, assayed, and marked, 

 so as to distinguish between the qualities of the 

 soils contained in them severally, and three 

 grains of buckwheat were planted in each. The 

 resultant crops were harvested on the same 

 day, and examined and measured under pre- 

 cisely the same conditions. The size and vigor 

 of the plants were found to be almost exactly 

 in proportion to the amount of vegetable 

 mold that had been placed in the jars. Other 

 experiments showed that mixtures of calcined 

 loam and sand were capable of bearing abun- 

 dant crops when supplied with nitrogenized fer- 

 tilizers, such as the nitrates of potash and lime. 

 The result of the experiments as a whole in- 

 duced the conclusion that the nitrogen of the 

 soil is of very great value as plant-food under 



