422 Manufacture of Lanthorns^ 
r 
tember and May^ on account of the materials being so lia- 
ble to putrefaction. For the same reason they omit no 
Sundays^ the necessity of the business requiring it. I 
think about 21b. of rosin per hundred weight, would make 
the glue better, and enable the manufacturer to work a 
month longer. 
On the Art of covering IFire Cloth with a transparent 
V zrnish^ as a Substitute for Horn ; and on other Oh * 
jects of public Utility. By Alexis Ro c h o n , of the 
National Institute of France^ ^c.^ 
IN the progress of the present war, the marine store- 
houses of France were totally without the essential article 
of horns for lanthorns. It was impossible to substitute 
glass in the place of this article, on account of its brittle- 
ness, and the obvious danger which might result from 
that quality. In this situation of distress, the agents of 
the French government consulted Citizen Rochon, and 
directed him to make every experiment he could think of 
to discover a proper substitute. His attention was first 
directed to a memoir of the celebrated Poivre on the fa- 
brication of lanthorns of horn by the Chinese, It is 
known that this industrious nation prefer horn to glass on 
account of its cheapness and toughness, and that they pos- 
sess the art of welding this substance together with so 
* Extracted from a memoir read to the National Institute oF 
France the 21st Ventose, in the year VI. (March 1 1th, 1798), and 
inserted in the Journal de Physique for April 1798. The memoir 
contains various political and economical observations more par- 
ticularly applicable to France, with general observations, which I 
have not thought it necessary either to transcribe or abridge ; 
neither have I been solicitous to take the very words of my 
aUthoi’ in the parts I have abstracted. N. 
