AGRICULTURAL CHEMISTRY AND GEOLOGY. 175 



New Method of Determining Nitrogen. 



Dr. Simpson, of Dublin, has presented to the Chemical Society a communication re- 

 specting a new process for estimating nitrogen. There are two modifications of his method. 

 The first served for determining the comparative amount of nitrogen and carbonic acid 

 formed during the combustion of an azotized organic substance. It did not differ widely 

 from Liebig's process now in use, except that oxide of mercury, diluted with oxide of cop- 

 per, was employed for burning the substance, and chlorate of potash was placed at the end 

 of the tube to yield a supply of oxygen. The absolute method resembled Dumas's in prin- 

 ciple; carbonate of manganese, however, being the substance employed for the production 

 of carbonic acid, and some peculiar arrangements being introduced, especially in the 

 receiver over the mercury trough. These processes had been worked out in Bunsen's labora- 

 tory ; and were equally applicable to the determination of nitrogen in such substances as the 

 vegeto-alkaloids, in nitrates, or in salts of ammonia. 



Phosphate of Lime— A New Test. 



The action of boracic acid upon the phosphate of lime, as described by C. Tissier in the 

 Comptes Rendus, (Paris,) is exceedingly interesting to agricultural chemists: If to an acid 

 solution, either nitric or muriatic, containing phosphate of lime (or a soluble phosphate and 

 chloi'ide of lime) and an excess of boracic acid, there be added borate of soda in sufficient 

 quantity to saturate the acid which holds the phosphate in solution, no borate of lime is 

 precipitated, but all the phosphoric acid is thrown down in the form of phosphate of lime. 

 This precipitate has not a variable composition, like that formed by being saturated with 

 ammonia, but has a constant composition and a well-defined formula. It coi'responds with 

 that for which Berzelius gives the formula, 8 Ca. 0, 3 P O 5 , and which contains phosphoric 

 acid, 49-09; lime, 50-91. This method of precipitating phosphoric acid from its solution will 

 greatly facilitate the determination of the quantity of phosphates contained in soils and 

 manures. 



Value of Soil-Analyses. 



At a late meeting of the Farmers' Club in New York, Prof. Mapes adduced the follow- 

 ing circumstances, as showing the value of soil-analyses: — At the meeting of the National 

 Agricultural Society in Washington, Mr. G. W. Custis stated that he was owner of the 

 Arlington Estate, containing some 5000 acres of land and several hundred negroes. For 

 several years he had found it necessary, in order to pay his own expenses and those of his 

 family, (including the negroes,) to mortgage the estate. He had an analysis made of his 

 6oil, with a view to ascertain its deficiencies for a wheat crop, and, under proper instructions, 

 he had those deficiencies supplied; and "Now," said he, " gentlemen, I can say, instead of 

 mortgaging my estate, I am continually lessening the mortgages I had previously obtained, 

 and this year I have ten thousand bushels of wheat for the miller, while until the analysis 

 was made I never was able to sell a single bushel of wheat above what was used for the 

 hands." Mr. John Jones, of Delaware, the largest wheat-grower within two hundred miles 

 of Washington, said he bought a farm for $10 an acre, which he agreed to pay in small 

 instalments and on a very long mortgage ; the owner being glad to sell at that low price and 

 on those easy terms. AVhen he commenced operations, his first crop of wheat was some seven 

 or eight bushels to the acre, on the plan of cultivation usual in the neighborhood. He sent 

 his soil North to have it analyzed. On the basis of the analysis he planned his operations ; 

 and, " Gentlemen," said he, "I raised a larger crop of wheat than any other man within the 

 6ame distance of Washington. The assessors this year valued my land at $70 an acre, cal- 

 culating from the value of the crop of wheat." These cases had come under his (Prof. M.'s) 

 supervision, and the preparation which he recommended, after analyzing the soils, was a 

 mixture of guano with bones dissolved by sulphuric acid. They had added sulphate of 

 ammonia, which had cost them only as much as the carting of barn-yard manure had usually 



