COEEIGENDA. 
PAGE 
18, extract, 6th line from bottom, for “ou” read “on.” 
22, line 4 from top, after “ is ” dele comma. 
25, line 15 from top, for “ correspondes ” read “ correspondsand for “ mirit ” read 
“ merit.” 
30, line 23 from top, for “ spot” read “ spots.” 
37, first line ,for “rounds” read “weights.” 
— last line but one, for “ top ” read “tops.” 
40, round 34, for “ S ” read “ Sc.” 
42, round 5, insert tabular information for that round. 
47, line 11 from top, for “batteries. The &c.” read “batteries,—the &c.” 
EEEATA. 
Page 208, line 9 from the top, for “then the angle HFC = FSG- — <pf 
read “ then the angle HFc = FSG- = 0.” 
„ „ „ 13 from the top, for “ FH = cF cos <|> = x cos 0,” 
read “ FH = cF cos 0 = x cos 0.” 
„ 209, 210, for “P” and “P',” everywhere read “jp” and “jp'.” 
In both figures in the article, the centre of the smaller wheel should be “c M 
and of the larger “ C.” 
