130 pr. lire on Gunpowders 



Length of the parallelepiped . . 16^ feet. 



Width 10| 



Height 7i 



Radius of the cylinder . . . 5 f 



Height or length of semi-cylinder . 16^ 



Whenever the workman has introduced into each pot its 

 charge of ten or twelve hundred weight of crude sulphur, he 

 closes the charging doors carefully with their iron plates and 

 cross-bars, and lutes them tight with loam. He then kindles 

 his fires, and makes the sulphur boil. One of his first duties 

 (and the least neglect in its discharge may occasion serious acci- 

 dents) is to inspect the roof-valves and to clean them, so that 

 they may play freely before any expulsive force from within. 

 By means of a cord and chain, connected with a crank attached 

 to the valves, he can, from time to time, ascertain their state, 

 without mounting on the roof. It is found proper to work one 

 of the pots a certain time before fire is applied to the other. 

 The more steadily vapours of sulphur are seen to issue from 

 the valves, the less atmospherical air can exist in the chamber, 

 and therefore the less danger there is of combustion. But if 

 the air be cold, with a sharp north wind, and if no vapours be 

 escaping, the operator should stand on his guard, for in such 

 circumstances a serious explosion may ensue. 



As soon as both the boilers are in full work the air is expelled, 

 the fumes cease, and every hazard is at an end. He should 

 bend his whole attention to cut off all communication with the 

 atmosphere, securing simply the mobility of the valves, and a 

 steady vigour of distillation. The conclusion of the process 

 is ascertained by introducing his sounding-rod into the pot, 

 through a small orifice made for its passage in the wall. A 

 new charge must, now be given. 



By the above process, well conducted, sulphurs are brought 

 to the most perfect state of purity that the arts can require ; 

 while not above four parts in a hundred of the sulphur itself 

 are consumed ; the crude, incombustible residuum varying 

 from five to eight parts, according to the nature of the raw 

 material. But in subliming sulphur, the frequent combustions 

 inseparable from this operation carry the loss of weight in 

 flowers to about twenty per cent. 



