484 PHILOSOPHICAL TRANSACTIONS. [aNNO 1731. 



w. Now when the weights are at p and v, if the least weight that is capable 

 to overcome the friction at the points of suspension, c and k, be added to v, 

 as u, the weight v will overpower, and that as much at v as if it was at w. 



From what has been said above, the reason of this experiment will be very 

 plain. As the lines ac and kd, cb and ke, always continue of the same 

 length in any position of the machine, the pieces ad and be will always con- 

 tinue parallel to each other, and perpendicular to the horizon; however, the 

 whole machine turns on the points c and k, as appears by bringing the balance 

 to any other position, as abed; and therefore as the weights applied to any part 

 of the pieces fg and hi, can only bring down the pieces ad and be perpendi- 

 cularly, in the same manner as if they were applied to the hooks d and e, or 

 to X and y, the centres oi" gravity of ad and be; the force of the weights, 

 if their quantity of matter is equal, will be equal; because their velocities will 

 be their perpendicular ascent or descent, which will always be as the equal lines 

 4 1 and 4 L, whatever part of the pieces fg and hi the weights are applied to. 

 But if to the weight at v be added the littie weight u, those two weights will 

 overpower, because in this case the momentum is made up of the sum of v and 

 u multiplied by the common velocity 4l. 



Hence it follows, that it is not the distance c6 multiplied into the weight v. 

 which makes its momentum, but its perpendicular velocity l4 multiplied into 

 its mass. a. e. d. 



This is still further evident, by taking out the pin at k: for then the weight 

 p will over- balance the other weight at v, because then their perpendicular ascent 

 or descent will not be equal. 



j4n Account of a very profuse Vomit'mg of Blood, cured by the coldest Drinks in 

 the Winter-time. Communicated to the Royal Society by Peter Antony Michel- 

 lotti, M. D. and F. R. S. N° 419, p. 129. Jn Abstract from the Latin. 



In this communication an account is given of a young nobleman affected with 

 a scirrhosity of the spleen, who was cured of a profuse vomiting of blood, with 

 which he was seized in the winter of 1728,* by drinking water excessively cold, 

 and taking milk, barley water, almond milk, chicken and rice broth, and other 

 alimentary liquors, frozen by setting the vessels containing them in a mixture 

 of pounded ice and nitre. At the same time a sponge wet with cold vinegar 



* He had vomited blood i years before, and from early youth he had been subject to bleedings 

 from the nose every spring and autumn. Dr. M. mentions that in this attack the patient brought up. 

 by vomiting more than 12 lb. of blood in the space of 2 hours. (Sanguineni ad libras duodecim et 

 amplius duarum circiter horaruni ^patio e\ ore processisse.) 



