306 RED COLOUR OF THE PROTOSALTS OF MANGANESE. 
a perfectly transparent solution, without the least cloudi- 
ness. The two others, on the contrary, separated whitish 
flakes of e a resinous nature; like that noticed above, their 
quantity was small, but tolerably equal. 
If we seek the cause of this difference in their comport- 
ment, the explanation appears easy, by considering the age 
and state of vegetation of the plant. The multiplicity of 
species of the trees that yield copaiba may also cause a 
difference. In all cases where a cloudiness of this nature 
is produced by alcohol, particularly when the balsam is 
new and fluid, it cannot be considered as caused by adul- 
teration ; so also the results to be required from a trial by 
pure alcohol (which on the other hand easily demonstrates 
the presence of fat oils and consequently ought not to be com- 
pletely abandoned) ought to be modified in the following 
manner: — By intimate mixture with this liquid a deposit 
of a fluid fat oil ought not to be quickly formed, while a 
light flocculous cloud ought not to induce you to reject the 
yellow balsam, after it has in other respects exhibited a 
normal state, free from adulteration. — Chem. from Journ. 
de Phar made. 
ART. LXVIII. — ON THE RED COLOUR OF THE PROTOSALTS OF 
MANGANESE. By A. Volker. 
Many chemists have ascribed the red colour of the proto- 
salts of manganese to the presence of a higher oxide, and 
have described various methods for removing it. Thus 
Trommherz and Brandes advise precipitating a tolerably 
strong solution of a rose-coloured protosulphate of manga- 
