POWDER. 91 



other, without allowing it to remain sufficiently long on 

 either, to cool the plate. The powder will then be more 

 effectually aired, and more expeditiously dried, than by 

 the more common means of using one plate, which the 

 powder, by lying on it, soon makes cold, and therefore 

 the plate requires to be two or three times heated. 

 (This is another little discovery since the earlier edi- 

 tions.) Nothing preserves the strength of powder better 

 than, after being dried, to put it into canisters, securely 

 corked from the air. Mr. Butts latterly did so, by my 

 advice. Beware of going any where near the fire to 

 dry powder on plates. Recollect how far a hot cinder 

 will sometimes fly, and therefore, to be on the sure 

 side, run with your hot plates out of the room, and go 

 where there is no fire. As a still safer plan too, I 

 might name the use of a common pewter waterplate, 

 or dish ; by having recourse to which there can be no 

 risk of accident ; except that, through awkwardness, 

 the powder might be wetted, instead of being dried. 

 This way of drying is much on the same principle as 

 that which is now in general use in powder works ; viz. 

 by means of steam passing through pipes, or other 

 receptacles, by transfusion of heat through those pipes, 

 or cases, from which the air of the drying-room is heated 

 to as great a degree as is requisite for the purpose of 

 drying the powder. 



Good powder burns red in the pan, will keep its 

 strength for two years (or more, if made with due care 

 and attention to the principles before mentioned), and 

 may be had from most of the mills. 



As I formerly observed, Pigou and Andrews's has 

 the name of being the best, and is unquestionably most 

 excellent ; but I have never found any to please me 



