ON ACETIC ACID AND ACETATES. 2$5 



The principal advantages in the cylinder are, 1st, the Those of the 

 positive and negative powers are obtained in equal perfec- cy m er " 

 tion; 2d, it has but one rubber to keep in order; 3dly, it 

 is less liable (from the security of its form) to accidental 

 fracture, than the plate; 4thly, its insulation is more per- 

 fect; and 5thly, from the peculiarity of its structure, larger 

 multiplying wheels may be employed, and thus a consider- 

 able diminution of friction be obtained. 



The advantages of the plate machines are, 1st, they are* Those of the 

 less expensive than cylinders of equal power ;'2dly, they P Iatemachine * 

 occupy less room ; 3dly, may be constructed of a much 

 larger size, as instanced by Mr. Cuthbertson's large ma- 

 chine at Harlem; 4thly, several plates, to act jointly, may- 

 be more easily combined, than several Cylinders could; 

 5thly, the multiplying power may be applied to them to a 

 much greater extent, than it could to cylinders, without 

 rendering the motion too rapid; 6thly, plates of equal dia- 

 meters may be made to act with a uniform and equal de- 

 gree of power, a circumstance seldom attained by cylin* 

 ders. 



These are the only conclusions the present state of our Farther expe- 

 inquiry seems to warrant; many experiments remain to be run ^ nts to &• 

 made, and when a sufficient number of these are completed, 

 I shall not delay the communication of them to the public. 



3, Princes street. Cavendish square, 

 June 13th, 1810. 



XIII. 



Researches on Acetic Acid, and some Acetates : by Richard 

 Chenevjx, Efq. F. R. S. M, R. L A. fyc* 



JL HE identity of the acids contained in vinegar, and in the tf acetous 

 product of the distillation of verdigrise, is now generally acid » 

 admitted ; and the terms acetous acid and acetites have 



* Annates de Chimie, vol. LXIX, p. 5. 



Vol. XXYI— July, 18J0. Q peer* 



