332 Mijcellanea Curiofa 



A Difcourfe concerning the Mea- 

 fure of the Airs Refiftance to Bo- 

 dies moved in it. By the Lear~ 

 ned John Wallis, S. T. t). and 

 i R. S. 5. 



i.HpHAT the Air (and the like of any 

 JL other Medium) doth confiderably give 

 Refiftance to Bodies moved in it ; and doth there- 

 by abate their Celerity and Force is general- 

 ly admitted. And Experience doth atteft it : 

 For otherwife, a Cannon Bullet projected Ho- 

 rizontally, mould (fuppofing the Celerity and 

 Force undtminifhed) ftrike as hard againft a 

 Perpendicular Wall, ere&ed at a great di- 

 ftance, as near at hand j which we find it doth 

 not. 



2. But at what Rate, or in what Proporti- 

 on, fuch Refiftance is; and (confequently, at 

 what Rate the Celerity and Force is continual- 

 ly diminifhed, 1 feems not to have been fo well 

 examined. Whence it is, that the Motion of 

 a Project (fecluding this Confederation,) is com- 

 monly reputed to defcribe a Parabolick Line ; 

 as arifing from an Uniform or equal Celeri- 

 ty in the Line of Projection, and a Celerity 

 uniformly accelerated in the Line of Defcentj 

 which two fo compounded, do create a Para- 

 bola. 



3- In 



