392 
therefore had the name of its application on the title-page.” 
But the prosthapheeresis referred to seems most likely a method 
of solving spherical triangles, in which the product of two sines, 
or of a sine and cosine, &c., is avoided by the use of formule, such © 
as sina sin b= $ {cos (a—6b) —cos (@+b)}. This explains all 
Kepler’s allusions to prosthapheresis, and as Herwart proposed 
as the chief use of his tables to solve spherical triangles by direct 
multiplication without previous transformation, as set forth in 
his introduction, it justifies completely the use of the word on 
the title-page. 
Wittich was for a short time an assistant of Tycho 
Brahe, and his method of prosthapheresis appears to have been 
a method of solving triangles so as to avoid multiplications by 
means of formule, such as that just written, but I hope to 
examine the matter more fully. Laplace (Jour. de l'école polyt. 
Cah. xv. t. vil. 1809), referring to the same formula, 
sin asin b = 4 {cos (a —b) — cos (a + b)}, 
remarks that “cette manitre ingénieuse de faire servir des 
tables des sinus 4 la multiplication des nombres, fut imaginée 
et employée un siécle environ avant l’invention des logarithmes” 
(see Brit. Ass. Tables Report, p. 23, 1873). 
November 1, 1875. 
PROFESSOR BABINGTON, VICE-PRESIDEN!, in the Chair. 
The following communication was made to the Society : 
On Aristotle's notion of ‘ Right-Handedness’. By 
Mr Pearson. 
After referring to the paper by Dr Hollis on this subject, 
communicated last year (Nov. 30, 1874), the speaker stated 
that he had been led by Aristotle’s great reputation to enquire 
