ERRATA. 



Page 1C, line 15,/or ^M^" read Jf *. 



at dt 



38, line 21, /or "#and I" read " Fand A" 

 38, line 27, /or " E and I" read " F and A" 

 38, last line but one, for " El cos " read " VA cos 0." 

 38, last line, for " El" read " FA" 

 ., 39, line 17, /or " El cos " read " VA cos 0." 

 ,. 50, line 25, for " Oy\ " read " Oy'." 

 56, last line but one, for " fe = - 1 " read " It- = - 1." 

 58, line 15, /or " 38 and 40 " read " 38 and 41." 



