84 Mr. E. Howard Smart on a Formula for 



where 



si—ri 



/'to 



x(n— *») + w 



•' W- {<P-2X(*-r f )}^ 



with similar expressions for the dashed letters. 

 Expanding these in powers of X 



*>-('-?K0-?M^-;;> : +- 



Since ^L-i/^Yo. -/#Y 



r< 2W + 8W 



to the fourth power of (?//?')> 



4I('-S)"('^(-?))(|)'- 



Similarly 



nW'-JH) ■■■} 



-&{'-KS)'('-?)('-^) 

 -i©'(-2) (^ -©«©')}• 

 ™~5{>-e)('-*+3) 



25 n 



(*Y(_^Ii +37^-40* +2 



_i(K)Yi + ,5i_ M 5r + «,sr_«i«hi 



o \n / \ $i I ** I «i I Si / J 



these correct to the fourth power of — . 



