84 Proceedings of the Royal Irish Academy. 



It is interesting to show, from this point of view, that 



(ffl + \){l + A , 



= i2% 



(« + A) ^ (^ + a;^ 2' 



a + X & + A 4 (ff + A)^^ + A)' 



also 



g' ^ P A_ 8 /(X) _ /(A) 



{a + A)* (* + A)- 2 8A * (r^ + \){b + Aj (« + A)(* + X)' 



since 



hence 



2' — -0 



- 2; ^^ - (^2 + y'O' -r ax- + hf- + 2gx + 2/y + c. 



