428 PHILOSOPHICAL TRANSACTIONS. [aNNO I/IQ. 



Methodus Differentialis Newtoniana illustrata. Authore Jacoho Stirlingy* t Coll. 



Balliol. Oxon. N° 362, p. 1050. 



This paper on Newton's Differential Method, by that ingenious rTiathemati- 

 cian, Mr. James Stirling, may be seen, more complete and enlarged, in the 

 latter part of the author's treatise, " Methodus Differentialis, sive tractatus de 

 Summationeet Interpolatione Serierum Infinitarum;" first published in the year 

 1730, and again in 1764 ; also an English translation of it, by a Mr. Francis 

 HoUiday, in 1749. 



An Account of some Experiments to find how much the Resistance of the Air 

 retards falling Bodies. By J. T. Desaguliers, LL.D et F. R. S. N° 362, 

 p. 1071. 



- I took 12 balls, 6 of which were solid leaden globes of about 2 inches dia- 

 meter; 3 hollow glass balls of about 5 inches diameter; and 3 light pasteboard 

 hollow globes of about the same diameter; and having carried them to the 

 upper gallery in the lantern, on the dome of St. Paul's church, I let them fall 

 down by two at a time in the following manner: 



First, a leaden ball and a glass ball ; 2dly, a leaden ball and a glass ball ; 3dly, 

 a leaden ball and a glass ball. Then I let fall, in the same manner, the 3 other 

 leaden balls, each with a pasteboard ball. 



After that, having the leaden and pasteboard balls brought up again, I 

 repeated the experiment twice more with a leaden and pasteboard ball ; then I 

 made the experiment twice more with a pasteboard ball alone, to see how long 

 it would be in falling. 



On the whole it appeared, that the leaden balls were a very little more than 

 44- seconds in falling; the two largest of the glass balls d seconds; and the 

 pasteboard balls Q^ seconds. 



The height of the gallery, from whence the bodies fell, was 272 feet above 

 the pavement of the church, then covered with boards, on which they fell. 



The times of the falls were taken two ways above, viz. with a wheel chro- 

 nometer, which measures a small part of time accurately, nearer than to a 

 quarter of a second, made and contrived by Mr. George Graham, and with a 

 half-second pendulum ; and the differences of time between the fall of the leaden 

 balls and the other balls were taken below, by the president, Martin Folkes, 



♦ This very respectable mathematician was agent for the Scotch Mine Company, Leadhills, He 

 died the 5th of December, 1770. 



