1819.] < Oxides and Salts of Mercury. 331 



" The new mercurial ointment has been tried in two cases of 

 venereal ulceration of the tonsils, and one of chancre with bubo. 

 In all, the symptoms yielded regularly, ard the oare was eifected 

 in the usual time. In one case, the mouth became sore on the 

 fifth day ; in the second, on the L6th day ; in the third, there 

 was no sensible affection of the mouth. In none of the oases 

 was there any disturbance of the bowels. The advantages of 

 the ointment, as observed in the three cases alluded to, were, 

 that one drachm of it could be rubbed in effectually m about 12 

 minutes ; that it brought out no pustular eruption on the parts to 

 which it was applied, and that it left no stain upon the skin, or 

 upon the bed-clothes. (Signed) J. Siiiei n 



" King's Military Infirmary, Phoenix Park." 



Article II. 



Reply to Mr. Mellde on Centrifugal Force. 

 By the Rev. Patrick Keith. 



(To Dr. Thomson.) 



Silt, Bethersden Vicarage, Kent, Sept. 13,1819. 



Your correspondent Mr. Meikle, who has favoured us with 

 an article on centrifugal force, and the upright growth of vege- 

 tables, in your number for July last, condescends to make some 

 brief remarks on my paper on Mr. Knight's hypothesis, in your 

 number for April preceding. 1 am represented as entertaining 

 singular ideas of a centrifugal force produced by rapid circular 

 motion. What I have said is, that " the direction of the centri- 

 fugal force in question must of necessity have been oblique, as 

 being the simple effect of circular motion." Perhaps I should 

 have said a rotatory motion instead of a circular motion ; and, 

 perhaps, the term oblique is opt sufficiently applicable. But it is 

 plain that I am speaking merely of the centrifugal force, or 

 acquired momentum, by which the wheel was now capable of 

 throwing off a body from its circumference in the direction of a 

 tangent, as will appear from my referring immediately after to the 

 possibility of a bean's being thrown off' from the rim ; and will 

 Mr. Meikle say that this was not a consequence of its rotatory 

 motion ( It was entirely so ; and was a capability that no other 

 motion could have communicated to it. For though the wheel 

 (if otherwise moveable) had been puiled backwards, or forwards, 

 or upwards, as quick as you please, still it would have thrown off'no 

 body that might have been lodged on its surface in the direction of 

 a tangent. ISor are mv ideas of this force so singular as Mr. Meikle 

 h.t> imagined. For Mr. Knight represents the centrifugal force 

 of his wheel as being always in proportion to the velocity, and, 



