Miscellanea Cariofa. 1 6 1 



COROL III. 



Let r be the Radius, and c the Circum- 

 ference of any Circle. I fay, that the Re- 

 liance upon the Conick Surface generated 

 by the Rotation of the Lineola GB about 

 AI, is equal to the Produd of c x BM into 



r 



GL 3 . For the Refinance upon that Conick 

 GB* 



Surface, is equal to all the Refiftances upon 

 the Lineola'GB, that is, to all the e ^ thafi 

 is, equal to the Circumference of the Cir- 

 cle (whofe Radius is BM) multiplied into e\ 

 that is, the Refrftance upon that Conick 

 c x BM 



Surface, is equal to x e, and confe» 



r 



cx BM GL* 



quently (by CoroL 2.) equal to x ■.' 



r GB* 



a-E.-D. 



PROB, I. 



To find a Curve Line, bj the Rotation 

 of which a Round Solid fba/I be gene* 

 rated, that, while ''tis moved in a fluid 

 Medium, in the Direction of its Axis % 

 fhall meet with the leafi Refifiance. 



(Fig. 24.) 



Let OG, GB, be two infinitely fmali Par- 

 ticles in the Curve fought, which rould a- 

 bout its Axis, will produce the Solid of 



