352 Contributions to Chemistry from the 
eterminations aré made it will be found convenient to employ 
printed forms for logarithmic calculation, the logarithmic con 
stants of reduction being printed upon the form itself in thei 
proper places.” 
even with the hardest combustion tubes. Where many a 
8. On the separation of Cerium from Didymium and Lanthanum, 
The methods which have been recently proposed for the sep- 
aration of cerium from lanthanum and didymium are familiar 
mixed oxalates are tested the oxalic acid is oxydized to carboni¢ 
acid before the characteristic cerium-yellow appears. For the 
purpose of testing it is sufficient to dissolve the salt to be exam- 
ined in nitric acid diluted with its own volume of water, to add 
a small quantity of pure peroxyd of lead and boil for a few 
minutes, when the smallest trace of cerium can be detected 
by the yellow color of the solution. The reaction is here ex 
actly analogous to that of nitric acid and peroxyd of lead with 
solutions of manganese, which last is oxydized, not as Crum 
supposed, to hypermanganic acid, but, as Rose has shown, 10 
Sesquioxyd. : 
When a solution containing a salt of cerium dissolved in st: 
pero 
* Such pri ' : journal at 4° 
such printed forms may be had from the publishers of this Ji 
