232 On the Manuring of Grass Land. 



•' The dry extract given by this operation was very similar to that obtained 

 by the previous o[)eratiou [in which heat was employed], and its amount of 

 nitrogen was 17'3 grammes per kilogramme, which differs but little from the 

 extract produced by infusions with heat. 



" After having ascertained the amount of nitrogen in these rariotis sub- 

 stances, I endeavoured to ascertain what modifications there might liavc been- 

 produced in the constitution of the hay, luider the influence of these various- 

 treatments. I shall at present only mention the most important mineral 

 principles, silica, phosphoric acid, lime, magnesia, soda, and potassa. 



^ Normal Hay, Treated with Treated cold, 

 per kilo. heat, per kilo. per kilo. 



Gr. Gr. Gr, 



Ash C9-011 39-r)91 35-155 



Silica 19-406 20-3()3 23-155 



Phosphoric acid 4-440 2-750 1-329 



Lime 12-637 9-359 8-681 



Magnesia .. .. 1-824 1-004 0-386 



Soda 15-956 3-931 1-153 



Potassa .. .. 12-527 0-900 1-395 



" "We see immediately from these numbers that the loss has been chiefly in 

 tlie potassa and soda, rather less in the phosphoric acid, and a little less again 

 in the lime and magnesia. 



" Hay may thus lose nine-tenths of the jiotassa, almost the sarae of soda 

 [these alkalies are indispensable to the formation of flesh and blood], from half 

 to three-quarters of its phosphoric acid, from a third to a quarter of the lime. 

 The apparent augmentation of the silica does not prove that the hay has not, 

 under the influence of water, lost a certain quantity of this substance, for we 

 shall very shortly see the contrary by the presence of silica in the ash of tlie 

 extract ; this ap[)arent augmentation combined with the real diminution of the 

 ■weight of the hay, is changed into a loss, comprised between 5 and 12 per 

 cent, of the silica in the original hay. 



" The comparison of the ash of the extracts with that of the original hay, 

 shows us, in a completely soluble state, the mineral principles removed from 

 the hay by these different treatments. 



That is to say, that extract of hay may contain, in the state of soluble com- 

 pounds, from 9 to 18 thousandths of its weight of silica, from 13-5 to 16 

 thousandths of phosphoric acid, in the state of phosphate, and from 25 to 36 

 grammes of lime per kilogramme of extract. 



" What is called hay tea appears, therefore, to form a very rational diink, 

 Avhich, independently of its aromatic, tonic, and stimulant properties, otVcrs to 

 young animals, under a form which pleases them, a food wliich is rich iii 

 nitrogenous principles, and containing, moreover, in very considerable propor- 

 tions, the principles necessary for the development of their bony structure. 



" Another consequence which appears to me to result from this work, is, 

 that under the influence of rain, even when uninjured by any fermentation, 

 Jucy must lose a considerable proportion of the organic and mineral principles 

 which are necessary to render it a good aliment. We have just seen that water 

 alone removes from it more than a third of the nitrogenous matters which it 

 contains.'^ 



