6 HIS TORT of the SOCIETK 



T H E O R. I. 



Sin A : fin a : : fin O : £n o. 



T H E O R. 11. 



„. A — a - A + a O — o O+o 



Sin : lin : : tan : tan , 



3 a 2 a 



T H E O R. III. 



rr A — a A + a O — o O + o 



1 an : tan : : tan : tan . 



2 2 2 2 



T H E O R. IV. 



Sin A X fin a : I : : fin^i±iti x fin ^^^1=-' -."^n^^ 



2 a a • 



Mr Fisher recommends, for the purpofe of remeoiabcring 

 thefe rules, to commit to memory the words Sao, Satom, Tao, 

 Sarfalm, formed from the abreviation of the terms of the above 

 proportions. It is obvious that thefe four theorems apply to 

 plane triangles, providing that, inftead of the fine or tangent of 

 a fide, you take the fide itfelf. 



No'J*^" ^^^'^■^' ^^' ^* Hope read a paper, giving an account of a Mi- 



BrHope'ona Hcral from Stroutiau in Argyleflaire, and of a Peculiar Species of 

 sll^nban™'" Earth contained in it. A fliort abftrad of this papei- was in- 



ferted 



