ERRATA. ^/^ 



p. 148, in the middle of tlie last line but one, for =1 read zr— -. 



Pt 



p. 154, line 4, for(^ — n — 1)d, read (" — n — '£)d 

 p. 157, last line, for indentical, read identical. 



p. 159, line 3, /or (Q.= + Rs' + Sz' + Tz"* + &c.)^ 



read (z+Qs + Rz' +S2;^+T5'' + &c.)' 

 p. 167, line 6, /or lrf^ + rf% read Ms + d'- 



p. 169, lines 2, 3 and 4, for Abck,c. + aBc&c. + &c. read 



Abc&i,c. + aBcScc. + &c. + &c. 

 p. 181, line 4, for pq read pQ 

 p. 198, first line, /or — k^, read +k^ 



