ERRATA. 



Page 25, the 9th line from bottom should read 



P 1? the inward pressure, being proportional to the square of the 

 density, i. e. to ^-\-b) v etC * 



Page 33, bottom of diagram, instead of Methyl isobutyrate read Ethyl 

 isobutyrate. 



Page 33, 6th line from bottom, instead of (A), p. 25, read (A,), p. 29. 



