various Species of Cinchona. 143 



sometimes rhomboidal, or with the soHd angles truncated : 

 these laminae are also often united in groups. 



2. It has hardly any taste, and is flexible under the teeth. 



3. It requires about five parts of water, at 10 degrees, in 

 order to dissolve it. 



4. It swells, when heated, nearly like tartar, of Vvhich it 

 has the smell ; it leaves a grayish residue, which dissolves in 

 the acids with effervescence, and which is only a mixture 

 of carbonate of lime and charcoal. 



5. Its solution does not alter turnsole tincture; and it is 

 entirely insoluble in alcohol. 



6. The fixed alkalis, both caustic and carbonated, decom- 

 pose it, and precipitate from it pure or carbonated lime. 



7. Ammonia does not produce ihe decomposition of it ; 

 which proves that this acid has a stronger affinity for lime. 



8. The sulphuric and oxalic acids form, with its solution a 

 little concentrated, two precipitates, which are in the one 

 case sulphate of lime, and in the other an oxaicUe with the 

 same base. 



9. It causes no apparent alteration in the solution of ace- 

 tale of lead, nor in that of nitrate of silver. 



10. Concentrated sulphuric acid, poured upon this salt 

 reduced to powder, blackens it slightlv; but there are no 

 pungent vapours liberated from it, as from the acetates. 



11. What is remarkable is, that the infiision of tan and 

 of some kinds of cinchonas, that of Santa- Fe for instance, 

 produces a flaky yellow precipitate in the solution oF this salt. 

 Tile various phenomena caused by these experimerits an- 

 nouncing that this salt is formed of a vegetable acid and 

 lime, in order to decompose it and have the acid isolated 

 I made use of oxalic acid, which, as we know, is that which 

 xenders lime most insoluble by its combination with it. 



I proceeded in the following manner: — I dissolved, in the 

 necessary quantity of water, 100 parts of this salt; I after- 

 wards poured into the liquor, at different times, until there 

 was no more precipitate formed, a solution of oxalic acid, 

 the weight (jf which was known to me : it required 22 parts 

 of oxalic acid to precipitate all the lime, and yetlonly lound 

 27 parts of dry precipitate. 



Vol. 27. No. IOC. March 1607- K This 



