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tj? X [ 270 ] 



IXXX. On the Velocity of Reaction before Complete Equilibrium 

 and the Point of Transition are reached, §c. — Part II.* By 

 Meyer Wilde'rman, Ph.D., B.Sc. (Oxon.)f. 



Contents. 

 I. Velocity of reaction before complete equilibrium, &c, and the theory 

 of real and apparent freezing-points, boiling-points, vapour-pressures, 

 solubility, Src. 

 II. Velocity of reaction before complete equilibrium, &c, and physical 

 geography and meteorology. 



I. Velocity of Reaction before Complete Equilibrium and the 

 Point of Transition are reached, and the Theory of Real 

 and Apparent Freezing -Points, Boiling -Points, Vapour- 

 Pressures, Solubility, Sfc. 



THE equation for the velocity of ice-melting and ice- 

 separation established in Part I., shows that the equations 

 used in my paper " On the Real and Apparent Freezing- 

 points and the Freezing-point Methods " (Phil. Mag. Dec. 

 1897) have only to be corrected by the addition of the 

 instability constant in" order that the theory of real and 

 apparent freezing-points should be placed on a perfectly 

 correct basis. As is to be seen from Tables I. and II., the 

 values of C which are obtained from the middle part of the 

 curve, when the equation 



Q. = C ft. - {t - U instead of ~ = C(t -t){t- t ov + K) 

 dz wS 



is used, differ only a little from the correct value of C, 

 obtained when K is taken into consideration. For this reason 

 ihe numerical data used for C in the above paper (see the cor- 

 rections in Phil. Mag., January 1898), which were obtained 

 with the sensitive 1/100° mercury-thermometer, do not differ 

 much from those which were obtained later on under much 

 more favourable experimental conditions, and by means of the 

 platinum thermometer. We can therefore safely assume, 

 that the theoretical conclusions and numerical values given 

 in the above paper, for my own method as well as for those 

 used by others, are essentially correct. Among other things 

 we may regard it as finally established, that the difference 

 between the real and apparent freezing-points, as well as the 

 difference between the real and apparent freezing-point de- 

 pressions, are, in the method used by me, only 0°' 0000 2 to 

 o, 00004, when the convergence temperature is below the 

 freezing temperature. In the same way all the rules given 



* For Part T. see Phil. Mag. July 1901, p. 50. 

 f Communicated by the Author. 



