128 



CHEMISTRY. 



species of fairy-ring fungi do not greatly differ. 

 Two species occurring at Rotbamsted contain 

 nitrogenous compounds to the amount of one 

 third of their dry substance, and give an ash 

 rich in potash and phosphoric acid. Their oc- 

 currence in pastures and continuance in growth 

 are dependent on conditions of manuring and 

 of soil and season. They are rarely developed 

 on rich soils, or on those which are highly 

 manured, or in seasons favorable to the general 

 herbage of the turf ; but they prevail wherever 

 the growth of the grass is inferior. Previous 

 to this discovery at Rothamsted, it was not 

 known that any plant could feed directly on the 

 organic nitrogen of the soil itself. 



According to P. de Gasparin, all granitic, 

 metamorphic, volcanic,schistous, and calcareous 

 rocks contain phosphoric acid. It may be said 

 that about 5 per cent, of the phosphoric acid is 

 combined with organic matters, and it is main- 

 ly this 5 per cent, which furnishes phosphoric 

 acid to plants. This small accumulation may 

 be increased by adding manure. To determine 

 phosphoric acid, the author recommends that 

 the sample of earth should be treated by aqua 

 regia having an excess of hydrochloric acid. 

 In the filtered liquid ammonia is added slowly, 

 and not in sufficient quantity to make the 

 liquid alkaline. Afterward an excess of am- 

 monia is added, and all the phosphoric acid is 

 left in the precipitate. This is calcined, ground 

 to a fine powder, and treated with nitric acid 

 of -^ strength. The filtered solution is pre- 

 cipitated by ammonium molybdate, etc. 



Mr. R. Warington's experiments at Roth- 

 amsted have confirmed the soundness of the 

 theory of Messrs. Schloesing and Mtintz, that 

 nitrification in sewage and in soils is the result 

 of the action of an organized ferment. The 

 evidence for this theory is now very complete. 

 The process of nitrification is strictly limited 

 to the range of temperature within which the 

 vital activity of the living ferment is confined, 

 going on with slowness at 0., reaching its 

 maximum at 37, and ceasing at 55. It is 

 also dependent on the presence of plant-food 

 suitable for the formation of organisms of a 

 low character ; it is prevented by antiseptics 

 and by heating to the boiling-point; and it 

 can be started in boiled sewage or other ster- 

 ilized liquid by the addition of a little surface 

 soil or a few drops of a solution already 

 nitrified. Evidences of the presence of the 

 nitrifying organism have been found in the soil 

 from the surface down to a depth of eighteen 

 inches, which may be regarded as the limit in 

 an ordinary clay soil. In a snndy soil and a 

 clay that is penetrated by worms, it may go 

 lower. It is most abundant in clay at about 

 six inches below the surface. The analyses of 

 soils and drainage waters have taught that the 

 nitrogenous humic matter resulting from the 

 decay of plants is nitrifiable; also that the 

 various nitrogenous manures applied to land, as 

 farm-yard manure, bones, fish, blood, rape-cake, 

 and ammonium salts, undergo nitrification in 



the soil. As ammonia is so readily nitrifiable, 

 we may safely assert that every nitrogenous 

 substance which yields ammonia when acted 

 upon by the organisms present in the soil is 

 also nitrifiable. Besides ammonia, two amides 

 and two forms of albuminoids have been found 

 nitrifiable, but in those cases the formation of 

 ammonia preceded the formation of nitric acid. 

 In a solution containing a nitrifiable substance, 

 supplied with the nitrifiying organism and the 

 food-constituents necessary for its growth and 

 activity, the rapidity of nitrification will depend 

 on a variety of circumstances, among which 

 are the weakness of the solution ; temperature ; 

 deficiency of light; the presence of oxygen; 

 the quantity of the nitrifying organism ; and 

 the degree of alkalinity of the solution. 



A. Guyard. recommends the following tests 

 for the determination of nitrogen in the soil : 

 For ammoniacal nitrogen, calcium carbonate, 10 

 grammes to 100 grammes of soil ; for organic 

 nitrogen readily transformable into ammonia, 

 magnesia subcarbonate, five grammes ; for ni- 

 trogen tolerably easily converted into ammonia, 

 calcined magnesia, two grammes ; for nitrogen 

 transformable into ammonia, calcined lime, one 

 gramme; for second portion of nitrogen trans- 

 formable into ammonia, caustic potash or soda, 

 0'5 to one gramme ; finally, organic nitrogen by 

 combustion with soda-lime. 



Vegetable Chemistry. Hansen, assistant to 

 Prof. Sachs, has published accounts of his more 

 recent researches on the composition of chlo- 

 rophyl. The coloring - matter was extracted 

 with alcohol from the decoction of young 

 wheat, and the extract saponified. The sosp 

 is then precipitated by adding an excess of 

 chloride of sodium, and the yellow constitu- 

 ent of the color is separated with petroleum 

 ether. The soap is then cleansed with ether 

 and treated with a mixture of ether and alco- 

 hol, which removes the green constituent; when 

 purified and separated from the solution, this 

 crystallizes out in beautiful spherical crystals. 

 Chlorophyl green is opaque in the solid state, 

 and appears of a black-green color, possessing 

 no fluorescence, although it has that property 

 (red) in solution. It is shown that some of 

 the changes it appears to undergo with acids 

 as described by authors are not due to their 

 action on pure chlorophyl green, but on other 

 unknown bodies. It is free from sulphur and 

 from iron. The elementary analyses agree very 

 closely, and, calculated for the ash-free sub- 

 stance, are as follow : 



The amount of carbon is 1 per cent, too low 

 in both cases. 



Chlorophyl yellow occurs in about the pro- 



