284 Scientific Intelligence. 
tion can easily be tested for a small quantity of phosphoric acid, in 
order that when present, even in minute quantity, it may not be over- 
looked in the analysis. 
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resent. In the filtered solution the bases are determined according to 
the usual methods. 
The insoluble residue contains the whole amount of phosphoric acid 
which was present in the compound, as well as the alumina and the 
peroxyd of iron. It is dissolved in dilute hydrochloric acid, and the 
baryta removed by sulphuric acid. The filtered solution is saturated 
with carbonate of soda, and evaporated to dryness ; the dry mass 1s 
mixed with silica and carbonate of soda, and heated to redness. The 
calcined mass is digested in water, and carbonate of ammonia added 
o it, when a considerable amount of silica is precipitated ; itis filtered. 
ire ee 
