66 Mr, Smithson on a Substance from the 



Sulphuric, phosphoric, oxalic, tartaric, and citric acids, occa- 

 sioned a similar precipitation in solution of ulmin. 



Distilled vinegar produced no turbidness in it; and the 

 mixture being exhaled to dryness, at a gentle heat, was found 

 to be again wholly soluble in water. But when the mixture 

 was made to boil, some decomposition took place. On adding 

 muriatic acid to a mixture of solution of ulmin and distilled 

 vinegar, a precipitate was produced, as in a mere solution in 

 water. 



The nitric and muriatic acids received a femall quantity of 

 lime and iron from the ulmin, and I believe also a little mag- 

 nesia ; but these can be considered only as foreign admix- 

 tures. 



4. To acquire an idea of the quantity of potash in ulmin, 

 4, grains of ulmin were decomposed by nitric acid. They 

 afforded 2.4 grains of resin-like matter. The nitrate of potash 

 obtained was heated to deflagration, in small quantities at a 

 time, in a platina crucible to free it from resin. The alkali 

 produced was supersaturated with nitric acid, dried, and slightly 

 fused. It then weighed 1.2 grains. If we admits of nitrate 

 of potash to be alkali, this will denote -^ of potash in 

 ulmin. 



5 grains of ulmin were decomposed by muriatic acid. The 

 resinous matter weighed 3.5 grains, and the muriate of potash, 

 after being ignited, dissolved away from the charcoal, dried, 

 and again made red hot, weighed 1.4 grains. If we suppose 

 - of muriate of potash to be alkali, this will indicate -^^ of 

 potash in ulmin. 



2 grains of ulmin were made red hot in a gold crucible. It 

 then weighed only 1.05 grain. The form of the flakes was 



