NOTE ON THE OCCURRENCE OF A PECULIAR 

 PHOSPHATE OF ALUMINIUM IN A DEPOSIT OF 

 BAT GUANO. 



By Bernard DFi Coligny Marchand. B.A., D.Sc. 



{Read July lo, 1918.) 



In July, iyi6. a series of samples of bat guano, from a cave 

 n^ar Ermelo, were sent for analysis to the laboratory of the 

 Division of Chemistry. Two of the samples consisted of soft 

 white material found as nodules in the deposit. These samples 

 were found to contain large quantities of phosphoric oxide in the 

 form of aluminium phosphates. 



From the centre of one of the nodules a piece of pure white 

 material was selected and analysed separately. The selected' 

 j)ortion was found to contain : 



Per cent. 



AlPO^ 46.00 



(containing 26.78 per cent. P..O5) 



P2O,, : ... 53.58 



HoO 27.16 



corresponding to the formula Al.,Os.2P.XJ.. .SH/), which may 

 he considered to be an acid aluminium phosphate. The substance 

 was soluble in mineral acids, insoluble in citric acid and in 

 ammonium citrate, but half the phosphoric oxide could be dis- 

 solved out in ammonia solution. 



The mineral is white, and in some cases slightly yellowish, 

 very soft, rather softer than chalk, and no crystalline structure 

 was noticeable under the microscope. 



Another specimen, which was slightly yellow, and contained 

 ?. distinct trace of iron, was found to contain : 



Per cent. 



AlPO, 37-68 



PoO, 55 -60 



H26 28.48 



The only reference I have been able to find in the literature 

 ht my disposal to an acid phosphate of alumina corresponding to 

 the formula deduced from the first analysis above, is in Comey's 

 " Dictionary of Chemical Solubilities," where the author quotes 

 Millot, Bulletin des Seances de la Societe ckimique, 22, 244, 

 (1874), which paper I have not had the opportunity of consult- 

 ing. The natural occurrence of this phosphate has apparently 



