Methods of sieve analysis with particular reference to bone char

by the rather large amount of 626 j . Cottrell and Wolf end en state that their result is subject to considerable uncertainty, for it represents a difference between two experimental quantities and also rests upon a rather arbitrary extrapolation. Differences of extrapolation often do not affect the temperature coefficient, and it is perhaps significant that practically identical values of A C°v, that is d(AH°)/dT, were obtained by the two methods. Cottrell and Wolf enden found AH° to pass through zero at 26° C, in reasonably good agreement with 23° C at which the value of —log K2 given in table 3 reaches a minimum.