4 HISTORT of the SOCIETr. 



1793- Lit. CI. Mr Stewart read the remainder of the Biographi- 



Mar. i8. 



Eiogiaphicrii' cal AccouHt of the late Adam Smith, LL. D. 



account of Dr 



Smith. ... 



April 3. Ph'f- C!h Mr Playfair read fome Obfervations on Porifms, 



poiifmsl* ""' °" additional to thofe formerly communicated. Thefe were in- 

 tended to prove, that the proportions called Porifms do not, as 

 fome inathematicians have alleged, involve in them any viola- 

 tion of the laiv of continuity. This fubjed: belongs to the fecond 

 part of the paper, No. VII. of the preceding volume ; which fe- 

 cond part has not yet been fully communicated to the Society, 



MrFiflieron ^^ ^his meeting was alfo read a paper on Trieonometry, 



ttngonometry. "-' ^ ^ ° ' 



entitled, An Eafy and General Method for folving all the Cafes 

 of Plane and Spherical Triangles, by the Reverend Walter 

 Fisher, minifler at Cranfhoun. 



It has long been an objedl with mathematicians to reduce the 

 rules of trigonometry to the fmallefl number pofTible, and to 

 give them the form moft eafily retained in the memory. Lord 

 Napier, whofe difcoveries have fo much facilitated and abrid- 

 ged the labour of numerical calculation, applied himfelf to fim- 

 plify the rules of trigonometry with great fuccefs. He in- 

 vented the rule of the Circular Farts^ which gives an apparent 

 unity to theorems, where a real unity is wanting, and is per- 

 haps the moft fortunate attempt toward an artificial memory that 

 has been made by any of the moderns. 



Various improvements of this rule have lince been pro- 

 pofed. That of M. Pingre is one of the beft : He retains 

 Lord Napier's arrangement of the circular parts, and reduces 

 the rules of fpherical trigonometry to four ; the two firft of 

 which are Napier's, and the other two a generalization of the 

 common theorems refpeding the fegments, into which the 

 perpendicular, drawn to any fide of a fpherical triangle, di- 

 vides that fide, and alfo the angle from which it is drawn. See 



Mem, 



