ESTIMATION OF IRON, ALUMINA AND PHOSPHORIC ACID. 163 



reported in my account of the Chau-an tribe in this Journal, 

 Vol. xl, pp. 107-111. Metaphorically speaking, it is a 

 certain tree, rock, spring, sandridge, or other natural 

 feature in the family hunting grounds, which produces or 

 bears the child, and confers its totem upon it, instead of 

 these functions being performed by a human mother. 



The above correction applies to Vol. xvi, p. 71, of the 

 Queensland Geographical Journal. 



A SHORT and ACCURATE METHOD for the ESTI- 

 MATION of IRON, ALUMINA, and PHOSPHORIC 



ACID WHEN OCCURRING TOGETHER. 



By Thomas Cooksey, Ph. d.. b. sc. 



[Read before the Royal Society of N. S. Wales, November 6, 1907. ~] 



As most of the results obtained by means of the following 

 process depend on the estimation of the phosphoric acid 

 left in the filtrates, I would like to commence this paper 

 by a description of a volumetric method for the rapid 

 estimation of that body which depends upon its precipita- 

 tion as a tricalcic phosphate. 



Some two years ago during an attempt to volumetrically 

 estimate calcium and barium by means of a phosphate 

 solution I found that, in the presence of an excess of 

 calcium chloride, tricalcic phosphate was precipitated 

 whenever the solution became alkaline to methyl orange, 

 and that phosphates could be simply determined by first 

 making the solution, which must contain excess of calcium 

 chloride, neutral to methyl orange, then adding a few drops 



