WASTE OF DIHJGS IN POMTDERING. 



opposite each other ; the twenty four screws are then with- 

 drawn, and the upper brass ring turned exactly half round, 

 which is determined by the lines before mentioned ; and by 

 this means the teeth of the circle are divided into two thick- 

 nesses, and being put together again in opposite directions, 

 if any error arose in racking the teeth, it would be shown 

 by the upper and lower halves of the teeth not coinciding 

 when reversed, and by racking them while reversed the 

 screw would cut away the inequalities, and make all the 

 teeth of the same size and distance from each other ; this 

 reversing the teeth is performed several times, till ihe teeth 

 are brought to a perfect equality in all parts of thte circle i 

 four steady pins are accurately fitted into the two rings to 

 hold them together in any of the positions in which they have 

 been racked together, and it is upon these the dependence 

 is placed for the coincidence of the teeth, the twenty four 

 screws being merely to hold them fast together, and fitted 

 rather loosely in their holes, that they may not strain the 

 steady pins. 



III. 



Observations on ihe Wastes that Puherization occasions in 

 Substances : by Mr. Hekrt, Chief of the central 

 Pharmacy of civil Hospitals, Sfc*. 



A. HE School of PJiarraacy being consulted by count de inquiry into 

 Cessac, ministre directenr de l" administration de la guerre^ '^^ ^^aste of 

 respecting the waste, that certain mineral, vegetable, and French^ ^^^ 

 animal substances, employed as medicines, experience on Government, 

 being powdered, appointed two of its members, to examine 

 particularly into a subject so interesting in pharmacy, and 

 to make a report on it. 



Report of the Committee to the Members of the School of 

 Pharmacy, 



Gentlemen, 

 You have appointed two of your members, to make a re-^ 



• Ann, de Chim. to!. LXXV, p. 324. 

 •*' port 



9 



