r 



W. J. Taylo?' an liock Guano. 



187 



Though the phospliate of lime is applied to soils, and, as such, 

 taken up by plants, there is no proof that it remains in that 

 form until the plants have need of it ; it enters into new combi- 

 nations, some of which may be quite as insoluble as this Centi- 

 nella rock. The phosphate of lime dissolved by the carbonated 

 waters always found more or less in soils,^ is decomposed by- 

 alkaline carbonates ; the lime would therefore be converted into 

 a carbonate, and a phosphate of the alkali would be formed.f 

 Boussingault and Levy, (Journ. des Debats, Dec. 5, 1852,) found 

 that the air in the interstices of arable soils contained as much 

 as 22 to 23 times as much carbonic acid as the atmosphere, and 

 when the soil has been recently moistened, 245 times as much. 

 Phosphate of lime lying in such a soil would be dissolved in a 

 comparatively short space of time. 



Carbonate of iron is present more or less in every soil, and 

 consequently, if in a soil the carbonate of iron and phosphate of 

 lime exist, both held in solution by a carbonate of the alkalies, 

 a mutual decomposition may take place,:{: consequently w^e may 

 have vivianite formed in the soil: instances are frequent of viv- 

 ianite in fossils of the greensand of New Jersey, § but geologi- 

 cal ages are not required to produce these changes. M. Jerome 

 Nickl^s has recognized its presence in human bones (Am. Jour, 

 of Sci., vol. xxi, p. 402); he found in a cemetery at Eumont, a 

 village in the department of LaMeurthe, the earth of which was 

 very ferruginous, two arm bones of a female, a cubitus and a 

 radius, having a deep bluish green color. Ou breaking, the 

 alteration was found to be complete, and a qualitative chemical 

 examination proved it to be phosphate of iron. It is to be re- 

 gretted that a quantitative analysis was not made, to have deter- 

 mined whether all the bone phosphate had been decomposed 

 and the transformation into phosphate of iron complete. M. 

 Nickl^s, on examining the medullary cavity with a lens, found 

 among the sinuosities left by the hardened marrow brilliant 



* Researches have been made by Lassaigne. Journ. Cliim. Med, [3] iv, 354; 

 and Ann. de Chim. et de Phys., [3], xxv, 346, show that phosphate of lime la 

 coHTcyed into the plant orgarmm by water saturated with carbonic acid. Dumaa 

 (Comptes Rendus, xxiii, 1018) holds the same opinion. , x * ,■ 



t Bischof, Chem. and PhyH. Geologv, vol i, p. 13, No. 19. Phosphate of hme 

 dissolved in carbonated water forms carbonate of lime, which is precipitated, and 

 alkaline phosphate which remains in solution. 



t Phosphate of lime dissolved in carlwnated waters and proto carbonate of iron 

 form a pruto-phospliate of iron, which is precipitated, and bi carbonate of lime 

 ^hit-h remains in solution. (Bischof. vol. i, p. 13. No. 20 ) , , , , 



In the green'*and of New Jer,<ey, the decomposition is not owing nrobably to 

 the carbonate of iron but to the sulphate resulting from oxydatim) of the iron py- 

 rites. (Risch<»f, Vi)l. i, p. 14, No. 21.) Phosphate of iron and proto-.^ulphate of iron 

 form sulphate of lime and proto-phosphate of iron. Similar changes probably result 

 «n this guano rock, as m many specimens we find crystals of gypsum recognizable 

 ^'Hh a pocket-leas. 



