PC as Teo a ee eae 
Miscellaneous Intelligence. 443 
Two plates of glass of great thickness were curved by the heat of a con- ’ 
- cave metallic plate, worked and polished, and then fitted together with a 
border of metal and filled with distilled water. Buffon thus made a lens 
one meter in diameter and of great power. But he pursued it no further, 
because of the difficulty of the work, and the enormous expense of pol- 
Lemolt and Robert have also made improvements in reflectors, em- 
ploying sections of glass more or less concave, cut from a sphere, in the 
e as above mentioned, and having on the convex part a ric 
plating of silver from electric deposition. These reflectors can be cheaply 
made and require little care. 
Lenses and reflectors of this kind have been used on the railroads of 
Paris. By combining the two, a new kind of lamp has been constructed, 
roads. : 
20 kilometers along a railway, producing the effect of a light- 
of the s i igieed 
:Micapictere: of Soda.—Mr. Melsens, Professor of Chemistry at 
the production of the chlorated bodies by means of an am 
Soda remaining unaltered. ; : ms 
. Mviseie’ tak obestved that the change will go on in i a and with 
93° O- than in boiling water, it precipitating when the water is 
