Photography.— Artificial Alcohol. 112 
Bichat. A celebrated juggler, Robert Hondin, will exhibit an electrical 
pendulum in which he has surmounted two important difficulties, to. wit, 
the disturbing influence of variations of current upon the motion of 
the pendulum, and the destructive influence of contact breakers. The 
construction of this pendulum bas given to horology a new mechanism 
out negative proofs on colledion and upon 2 a in the manner em- 
employs this agent in place of the 
the process of M. Blanquart-Ewrard 
lodid to prepare sensitive papers for positives in the shade and 
ds ; ording-to t anqua i 
0 ‘prepares a dry collodion of excellent quality, 
this chlorid he a 
oye pr 
_ To 100 grammes of ordinary non-sensitive collodion he adds 50 
centigrammes of dry and finely pulverized perchlorid of iron, having 
no acid reaction; he boils it for a quarter of an hour, and adds four drops 
of tincture of iodine and filters the mixture. ‘The glass being perfectly 
of the production of alcohol by means of water and illuminating gas. 
ult es 
ertheless M. Biot doubts the possibility of this change, because it re- 
intimate molecu ructure of the substance should be 
_ changed, a change to which we have no analogy in the transformations 
itherto made known. This difficulty however does not appear to MM. 
Trhuard and Dumas as insurmountable ; since in treating cane sugar 
* 
