CHEMICAL SCIENCE. 305 



The excess of weight being due to the estimation of the phosphoric acid 

 united to lime as bone phosphate of lime, while truly part of it, with a por- 

 tion of silica, is unked to the oxides present. 



These facts prove that mineral masses containing phosphate of lime, mny 

 be thuj formed from animal phosphate of lime, and present all the characters 

 whL-h we recognize in the phosphate of lime contained in the oldest plates. 

 Ad litional interest has been given to this subject, by the investigations of 

 Pi of. Booth of Philadelphia, and Dr. Piggott of Baltimore, who have ana- 

 lyzed specimens, in which the phosphoric acid had combined with both oxide 

 of iron and alumina. 



OX THE SOLUBILITY OF BOXES IX TTATER. 

 BY PROFESSOR WOHLEE. 



"When bone-dust, such as is commonly employed as manure, is left for 

 some time in contact with water, and the latter is filtered away, it is found 

 to contain appreciable quantities of the phosphates of lime and magnesia. 

 The same result is obtained when the water is freed from carbonic acid by 

 long boiling. By filtering water for months through the same mass of bone- 

 dust, it was found constantly to contain these earthy phosphates, and their 

 quantity even appeared to increase in proportion as the organic matter of the 

 bones became putrid in consequence of its long contact with water and air, 

 and the water flowing off became turbid and offensive. This fact seems to 

 have some practical value in agriculture, as it shows that without any arti- 

 ficial preparation the earthy phosphates may be extracted from the bones 

 and introduced into the soil in a state of solution, perhaps exactly in the 

 quantity necessary for their appointed functions, and that in the employment 

 of bone-dust as manure, all the preparation necessary is perhaps to lay it in 

 heaps during the summer, and keep it constantly moist. Liebig's Annalen. 



OX SILICIFICATIOX AXD THE CEMEXTIXG MATERIAL OF COX- 



GLOMEEATES. 



In the course of a recent discussion before the Boston Society of Xatural 

 History, Dr. Hayes stated that he had made a somewhat extended examina- 

 tion of the cementing material of the well-known Koxbury conglomerate, 

 and found that it was for the most part silicate of lime. There are cases 

 where finely-divided slate argilite forms, with silicate of lime, quite large 

 quantities of cement, uniting pebbles of considerable size ; but these exhibi- 

 tions are only another feature, referable to the action of the same silicious 

 compound. The Roxbury conglomerate contains chlorine, and as chloride 

 of calcium is readily decomposed by hydrous silica, it might be assumed that 

 the silicate of lime was thus formed. But the conglomerate is very fre- 

 quently traversed by bold dykes of trap, which contain a large amount of 

 sulphuret of iron, and the fissures in the conglomerate, being often filled 

 with sublimed quartz, the more probable supposition is, that silicate of lime 

 was formed by the transportation of silica in the heated vapor of water. 

 Such silica would combine with the lime and alumina of the comminuted 



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