ERRATA. 



Page 23, line 11, for there read these. 



,, 23, 25, for dzdy read dydz. 



" 29> - 7 > **% read ^- 



" 29 > " **- 



,, 36, 22, after co-ordinates, insert of. 



37, ,, 2 from bottom, for dV, read 5'V. 



,, 43, ,, 8, for axes, read axis. 



,, 46, ,, 19, after radius, insert is. 



53, ,, 7, for p-read (g). 



54, 11, for 47r/ 3 read 27r/ 3 . 



54, 16, for 47ra/ 2 read 4iraf s . 



56, 19, for 



60, 13,fcrJ^ 



64, ,, 4 from bottom, before a potential insert of. 



71, throughout for dw and dw read dw. 



72, ,, 18, for dw read dt7. 

 74, ,, 24, /or his read this. 



Z7(2) {J(i) 



84, ,, 11, for -^ read -^ . 



88, 20, for r 2 read r 3 . 



89, ,, 17, for sin 0' read sin 0. 



89, 18, for U read tf(D. 



90, ,, 2 / or ^ rga ^^- 



92 24, for |TT read ^_. 



d' 2 d) d 2 



107 , 20, for r 2 - = read r 2 -=-5 + 

 ' ' dx 2 dx 2 



123 ,, 19, for these read thus. 

 129 ,, 24, for sin -GT 



