T ii M o u in T o i- 1 r u \ \ r s 



from observation. To tin- right of thrv arc tin- equations of condition for the 

 correction oi the <-li incuts. 



A normal equation for Se is obtained by tnking the sum of all the equations. 

 That for in is formed by subtracting the sum of the first seven from the sum of 

 the last seven, and those for fe and e\j by taking the sum of the equations in 

 which the coefficients of le or e\o are greater than unity, after changing the signs 

 of the equations in which they are negative. The normals thus obtained are 



