VOL. XVI.J I .PHILOSOPHICAL TRANSACTIONS. 2/3 



An Experiment of Shooting by the Rarefaction of the Air. By Dr. D. Papin, 



R.S.S. N° 179, P-21. 



Ordinary wind-guns produce tlieir effect by the compression of the air ; but 

 Ottho Guerick found out a new sort that shoots by rarefaction, and he has pub- 

 lished that device at large in his book, on Pneumatic Experiments, I have there- 

 fore had the curiosity to try it myself by another contrivance, which I take to 

 be better than his ; first, because I can make a rarefaction much more perfect 

 than he could do. 2dly, because his device could only be used for guns of a 

 small bore ; whereas my way may be applied to the largest bores. So that one 

 might by this means throw up vast weights to a great distance. 



A A pi. 9, fig. 5, is a pipe, very equal from one end to the other. B B a small 

 pipe soldered to a hole near the end of the pipe A A, and applied to the plate of 

 the pneumatic engine. C C some kind of stool, to bear up the hinder part of 

 the pijje A A. Da piece of lead fitted to the bore of the pipe A A. 



The pipe A A is to be shut at both ends by valves outwardly applied, and so 

 the said pipe A A, though never so large, may be exhausted of air by means of 

 the pneumatic engine ; which done, the valve towards D must be suddenly 

 opened, that the whole pressure of the atmosphere acting on the lead D may 

 drive it along the pipe A A with such rapidity, that it will be able to carry it to 

 a great distance. And because such a valve shutting a great hole would prove 

 very difficult to be opened, when the pipe A A is of a large bore, the aperture 

 towards D may be left much smaller than the pipe; the velocity of the air being 

 so great, that even through a pretty small aperture it presses the lead D as freely 

 almost as if the whole bore was quite open. • - 



Having prepared a barrel carrying a lead of 2 ounces, the experiment wai 

 shown before the Royal Society ; and the effect was found very considerable, 

 the force being little less than that of the wind-gun by compression ; the same 

 experiment being afterwards repeated with a longer barrel, it was found that the 

 length in this way of shooting has very little, if any advantage. 



Part of a Letter from Dr. Salomon Reisel, chief Physician to the Duke of IVir- 

 temburg, concerning an Extraordinary Tincture given to a Stone. Stutg. Febr, 

 l2mo: l686. N° 179, P- 22. Translated and extracted from the Latin. 

 In this letter it is stated that a certain jeweller of Stutgard, named Christo- 



small charges or velocities the defect of range is not very great ; and besides, at elevations equally 

 above and below 45° the effects would be nearly equal, and therefore little or no difference would 

 appear ; only the lower elevation must range the farther, because passing through a less quantity of 

 resisting medium. So that ori the whole it appears that Mr. Halley had deceived himself by mean* 

 of an inadequate experimen<ju^jtl.i((: i.ivj u lo &JfW{; srfJ 980C|tja8 1 ^UO' : 



VOL. III. N N 



