ERRATA. 
Page 81 line 11, for “4 or 3,” read “ 4 to 3.” 
244 last line, &c. and page 245, line 13, for g and g’, read g and g’. 
251 line 1, &c. dele “or that of the compression to the extension 
of the external fibres, (since the compressions and extensions 
are here as the forces. )” 
259 line 4, for the divisor 50, read 60. 
265 line 12, for 9 the denominator, read 5. 
280 line 9, for .97, read —.97, , 
283 line U1, dele = g. 
297 et seq. to 305, are omitted by the printer’s mistake. 
473 in the title, for Grelly, read Grelley, 
N, B.—The separate table of birds is to face page 131,—The map of 
Troy is to face page 224. 
tMew 
