On constructing Electric Columns. 265 
that the nitric acid was not in such great. excess had a sufficient 
quantity of water been employed, and that the muriatic acid is 
not of so much consequence in the formation of protoxide of 
antimony, since the whole of the eleven fluid ounces there pre- 
scribed might have been omitted. 
I remain, sir, 
Your obedient servant, 
Loug Acre, April 17, 1816. Jos. Hume. 
=< 
“To Dr. Latham, &c. Sc. Be, 
‘* Sir,—A very simple and, I believe, effectual method of pre- 
paring tartarized antimony ‘oniaered to me yesterday, which I 
am anxious to present to you lest I should be anticipated un- 
fairly by any other experimentalist. 
*©T shall not at present take up more of your time thar to 
state the following sketch of the process. 
“The common black sulphuret of antimony is boiled with 
nitrous acid /arge/y diluted with water. This produces an oxide 
of antimony which, after being properly washed, is to be boiled 
with supertartrate of potass and distilled water. The operation 
is then to be finished in the usual manner by evaporation and 
crystallization. 
‘< T have the honour to be, Sir, &c. 
Long-Acre, Jan. 21, 1814. “ Jos. HuME.”’ 
LVII. On constructing Electric Colunms. By B. M. Forsrer, 
Esq. 
To Mr. Tilloch. 
Sir, — i HAVE lately formed an electric column, hy a process 
somewhat different from any hitherto adopted, I believe ; and 
imagining that it may prove a very convenient one, I wish by 
means of your publication to make it known, hoping that those 
persons who are interested about this curious instrument will 
make experiments to determine the comparative power of a 
column formed by this method, and one made according to Mr, 
De Lue’s original plan. 
Not being able easily to procure manganese in a finely-pow- 
dered state, which I understand has been made use of instead 
of platcs of zinc, 1 was desirous of trying the effect of z7c very 
finely powdered; and having obtained some of this substance 
pulverized, in order to get the very fine particles I sifted it 
through muslin, then mixed it with a solution of common glue 
and some moist sugar, ‘This mixture 1 laid on the back of 
Dutch~ 
