60 



THE FARMERS' REGISTER. 



donald as above given, it is eaid to amount to 15 

 per cent.* This greatly exceeds iJie quantity, 

 contained in the specimen examined l>y myseil'. 

 which gave me only 7 per cent, ol" pure an)monia. 

 Tlieeame is true ol the uric acid, which in my 

 eperimen did rioi amount to 1 per ceni.f In ihese 

 refeults a cenain laiiiude must be allowed for ne- 

 cessary differences, since ihe older the deposiie, 

 the less rich must the guano be in uiic acid and 

 ammonia. 



6. An important ingredient in the guano 's the 

 phosphate of liuie, and as this substance is nei- 

 ther volatile, so as to rise into the air, nor soluble, 

 60 as to be washed out by the rains, it is obvious 

 that the older the depnsi e and the less volatile 

 matter it contains, the richer it is likely to be in 

 this earthy phosphate. Supposing each specimen 

 free from sand, &c., the analysis o! Klaproih 

 gives 14.7 per cent., and that of Vauquelin 15 

 per cent., while the bone-earih in the third ana- 

 lysis is slated at 30^ per cent. 



In two portions which 1 examined, the phos- 

 phate of lime amounted in the one to 29, and in 

 the other to nearly 43 per cent, of the guano sup- 

 posed to be free from sand. In regard to this sub- 

 stance, therelore, the guano is no less variable in 

 composilion than in regard to its oiher consti- 

 tuents.! 



7. When cold water is poured upon guano a 

 large portion of soluble matter is talcen up, con- 

 sisting chiefly of common salt and of various salts 

 of ammonia, with a very little ol'the urate olsoda, 

 lime and magnesia. Aher careful washing with 

 water and drying at 160°, one portion leli 40 and 

 another 35 per cent, of insoluble residue, consist- 

 ing of phosphate and oxalate of lime with some 

 urate and other animal matters. It is these solu- 

 ble salts which act most immediately and most 

 powerfully when the guano is applied to the 

 growing crop. The earthy constituents, though 

 ot' great importance to the ultimate growth and 

 health of the plant, begin to manifest their in- 

 fluence at a later period. 



8. I have not thought it necessary to determine 

 with accuracy the relative proportions of the oxa- 



• Fifteen per cent, of pure ammonia are equal to 

 60 of bicarbonate of ammonia, 45 of sal ammoniac, 

 or 40 of oxalate of ammonia. As much of the ammo- 

 nia in guano exists in the state of bicarbonate, I doubt 

 if any of the specimens which come to this country 

 can ever contain so much as 15 per cent, of pure 

 ammonia. 



t One hundred grains of guano distilled with dilute 

 caustic potash, and the ammonia received into dilute 

 muriatic acid, yielded, on evaporation at 212°, 21.5 

 grs. of sal ammoniac, equal to about 7 grs. of ammo- 

 nia. The uric acid was separated by boiling in dilute 

 caustic potash, and precipitating by dilute sulphurie 

 acid. 



X Boussingault, after describing the astonishingly 

 fertilizing action ol the guano on the plains of Peru 

 (Annales de Chim.et de Phys., Ixv. p. 319,) says 

 that it consists of urate, oxalate, phosphate, and car- 

 bonate of ammonia and some earthy salts. This dis- 

 tinguished philosopher, to whom modern agriculture 

 owes so much, inclines to the hypothesis " that the 

 fariUity of the soil can be increased only by the addition 

 of substances containing nili-ogen." (ibid. Ixvii. p. 16,) 

 and therefore pays less regard to the earthy matters 

 which may be added to the soil. We are indebted to 

 Sprengel for illustrating the important influence of 

 inorganic substances in nourishing and promoting the 

 growth of all living vegetables. 



lie and carbonic acids, or of the several salts of 

 ammonia, in a substance so variable in its consti- 

 tution. In the only specimen in which I sought 

 Ibr it I delected no eensible quantity of poiash. 

 It is true that Fourcroy and Vauquelin Ibund 5^ 

 percent, of sulphate ol potash, but this can only 

 be considered as accidentally preseiii in the speci- 

 men they examined, since it is not easy to under- 

 stand how potash should be more abundant than 

 soda in the excrements of eea-lbwl, living almost 

 entirely upon the fish of the Pacific Ocean. 



9. Finally, the variable con^liiuiion ol Ihe gu- 

 ano brought to this country, and now ofl'ered /or 

 sale in England, will a[ipear by the (ollowing ge- 

 neral results of the analysis of two small fiortions 

 taken at random from a box coniaininsi about 20 

 pounds' weight. The first contained 8 per cent, 

 and the sicond only 1 15 per cent, of sand. 



1. per cent. 



Water, sabs of ammonia, and organic 



matter expelled by a red Ileal - 23 5 



Sulphate ol soda - . . . 1-8 



Common salt, with a little phosphate 



of soda 803 



Phosphate of lime, with a little phos- 

 phate of magnesia and carbonate of 

 lime* _ - . . . 44-4 



Ammonia . . - - - 

 Uric acid ..... 

 Water cind carbonic and oxalic acids, 



&c. expelled by a red heat 

 Common salt, with a little sulphate 



and phospliaiK of soda 

 Phosphate of lime, &c. 



100 

 per cent. 

 70 

 0-8 



61-6 



114 

 29 8 



100 



On ihe cause of ihe fertilizing action of gu- 

 ano. — Though so variable in composition, howe- 

 ver, the nature of the substances it appears al- 

 ways to contain enables us to explain why it ex- 

 erts so marked an efiect on the growth of plants, 

 as well as to answer one or two oiher questions — 

 in regard, for example, to tlie duration of its ac- 

 tion in leriilizing the land — and to the cause of its 

 accumulation on t iC coast of Peru. 



1. The most important and most active ingre- 

 dient contained in the decomposed guano import- 

 ed into this country is the ammonia. This sub- 

 Biance, there is reason to believe, acts in a most 

 energetic manner upon vegetation in every cli- 

 mate — it is one of the most useful ingredients 



* The results above given indicate the proportions 

 of the alkaline and earthy salts as they existed in the 

 ash that was left when the guano was heated to red- 

 ness in the air. The chemical reader will understand 

 that very different numbers would have been obtained 

 had the soluble salts been separated from the insoluble 

 before either of them was heated to redness. This 

 arises from the circumstance that, when the crude gu- 

 ano is heated, the phosphate of ammonia and oxalate 

 of lime are simultaneously decomposed, and phosphate 

 of lime is formed, whereas, were the phosphate of 

 ammonia previously removed by washing, the oxalate 

 of ammonia would, by the burning, beconverted only 

 into carbonate. With a view to a merely economical 

 object it did not appear to me necessary to enter into 

 a rigorous examination of the relative proportions of 

 the several salts of ammonia present in such variable 

 quantities in ihe guano. 



