FRl.VClPLr.S OF SULPHURIC ACID. 349 



run on a slip of brass, moveable under the screws %"j e, 

 to adjust the barrel to the knife. K, K, (Fig. 1 and 2) a 

 strong bar of cast iron, to which the knife is screwed, 

 moving lengthwise on friction-rollers between the pieces of 

 wood L, L, L, L, on the frame G, as at K, (Fig. 4). The 

 pieces of wood L, L, L, L, are each moveable under two 

 icrews, by which they are adjusted to steady the motion 

 of the knife-bar. M, M, (Fig. 1 and 2) is a roller at the 

 back of the knife, to which it is kept close by a weight N, 

 at each end, acting over pulleys, as atO, (Fig. 2) suspended 

 from the slider p, between which the roller is placed ; by 

 drawing the spare skin over this roller, as it is cut off, it 

 keeps both sides of the skin equally up to the knife, and 

 makes it cut more uniform. Q, Q, is a lever acting on a 

 pin r, and moving another lever S, S, by means of a pin 

 and a notch #, which acts on another pin at u ; and by 

 means of the two pins at AV it moves the knife lengthwise to 

 and fro : as fast as the skin is cut the barrel is drawn round 

 by the weight X. 3/ is a guide to the lever, from which end 

 it is worked. 



VI. 



A Memoir on Sulphuric Acid; hy Mr^ Klaproth : read at 

 the Philomathic Society of Berlin *. 



A HE object of the author was to ascertain the respective Proportions of 



^quantities of the elements of sulphuric acid and of sulphate ^^^ elements of 

 ^ ^ ^ sulphuric acid 



ot barytes, and he mentions the analyses that have been according to 



made of these substances by the chemists whose names are^^"^"^^"^^***** 



nubjoined: 



* Abridged from the German by Mr. Bergman. Anpahs 4t 

 ^Chime, Vol. JLVIII, p. 122, May, 180S. 



