424 Manufacture of Lanthorns> 
ed his wire cloth, which came out with its interstices filled 
with the compound. It is requisite that the size should 
possess a determinate heat and consistence, concerning 
which, experience alone must guide the operator. 
When this prepared wire cloth is fixed in the lanthorn, 
it must be defended from moisture by a coating of pure 
drying linseed oil ; but even in this state it is not fit to be 
exposed to the weather. The ease with which these Ian- 
thorns are repaired in case of accident, by a slight coating 
of glue, is pointed out as a great advantage by the inven- 
tor, who likewise informs us that they were used in the ex- 
pedition to Ireland as signal lanthorns, though contrary to 
his wishes. For this use he recommends the large plates 
of mica, which v»^ere then imported from Boston. With 
the latter substance, enclosed between two pieces of very 
open wire cloth, he made certain squares, 26 inches in 
length and 18 in width, for the light-house at Ushant, 
which had been damaged by a flock of wild ducks, that 
flew through the windows and dashed out the lights. 
Citizen Rochon affirms, that lanthorns of wire cloth, 
prepared in his method, are much cheaper than those 
made of tin and horn ; that they are very cheaply repair- 
ed, and afford a stronger light. 
He applied coarse iron wire cloth to another use, which, 
he thinks, may be worth attention in future. He made 
the roof of one of lus workshops of this wire-cloth in or- 
der to avoid the danger of fire, and covered it with a slight 
coating of plaister. He thinks that a composition of 
lime and pounded scales of iron would have been pre- 
ferable. This coating ought not to be thicker than a slate ; 
and he recommends that it should be penetrated with 
boiling whale oil, and painted with tar and ochre. Such 
a roof would afford no hold for the wind, and might, as 
he apprehends, be of considerable use to defend buildings 
tiud sheds which require particular defence against fire. 
