ERRATA. 



Page 344, line 2 from bottom,/or " parallax," read " horizontal parallax." 

 407, 2, for " the body," read " a fixed body." 

 ,,410, 3, for "vo," read"dv." 



AIQ 10 jf "<ZN" j " a" N " 



,, 4io, ,, id, for read 



dy dx 



424, 4, for " 1740," read 1747." 



> 9, for " distance," razrf u disturbance." 



426, 20,/or " (u*" read " (h*" 



,, 428, ,, 21, same correction. 



,, 431, ,, 8, for " rate," read " ratio." 



436, 24, for "at," read "as." 



,, 451, ,, 1, for "accurate," read " inaccurate." 



