39 * 
Dr. Wollaston’s Analysis of 
triple crystals, which may be again precipitated from it as crys- 
tals by volatile alkali; and if the solution has not been aided by 
heat, scarcely any of the phosphorated lime will be found 
blended with them. 
In one trial the triple crystals exceeded of the quantity 
employed : but it seemed unnecessary to determine the exact 
proportion which they bear to the other ingredients in any one 
instance, as that proportion must vary in different specimens of 
such an assemblage of substances not chemically combined. 
Marine acid, poured on the remainder, dissolves the phos- 
phorated lime, leaving a very small residuum. 
This is soluble in caustic vegetable alkali entirely, and has 
every other property of mere lithic acid. 
The presence of volatile alkali in the compound stone may 
be shewn in various ways. 
(12.) In the distillation of this stone there arises, first volatile 
alkali in great abundance, a little fetid oil, and lithic acid. There 
remains a large proportion charred. Water poured upon the 
remaining coal dissolves an extremely small quantity of a salt, 
apparently common salt, but too minute for accurate examina- 
tion. Distilled vinegar dissolves no part of it even when pow- 
dered. Marine acid dissolves the phosphorated lime and phos- 
phorated magnesia, leaving nothing but a little charcoal. From 
this solution vitriolic acid occasions a precipitate of selenite, af- 
ter which triple crystals may be formed by ad . ition of volatile 
alkali. 
(13.) Marine acid also acts readily upon a fragment of the 
stone, leaving only yellowish laminae of lithic acid. When the 
solution has been evaporated to dryness, sal ammoniac may be 
sublimed from it ; and the two phosphorated earths are found 
