94 Proceedings and List of Fapers read. 



gen scales. But Chappuis's numbers only apply when the glass ther- 

 mometers are treated and read in the way in which he treated them 

 in his comparisons. That is the great advantage in using the Tonnelot 

 thermometer. It is not an absolute but an intermediate standard. It 

 is immaterial whether Chappuis's method of treating a glass thermo- 

 meter can be improved upon by adopting a different way of obtaining 

 the zero, or by making corrections for effects of capillarity. It is 

 sufficient to know that consistent results can be obtained if the thermo- 

 meters are always treated in the same way, and whether that way is 

 good or bad, it is the only one which can be used, if we wish to refer 

 the temperature measurement to Chappuis's hydrogen thermometer. 

 For this reason, and also because we have not at present any guarantee 

 that flint glass thermometers agree sufficiently in composition to give 

 identical results, Mr. Sworn's conclusions cannot at present be accepted 

 as final. Mr. Chree's experience* tends in the direction of indicating 

 differences in the behaviour of different thermometers nominally made 

 of the same glass. 



January 25, 1900. 



The LOKD LISTEE, F.E.C.S., D.C.L., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : — 



I. "Mathematical Contributions to the Theory of Evolution. — On 



the Law of Eeversion." By Professor Karl Pearson, F.E.S. 



II. " On the Mechanism of Gelation in Eeversible Colloidal Systems." 



By W. B. Hardy. Communicated by F. H. Neville, F.B.S. 



III. " A Preliminary Investigation of the Conditions which determine 



the Stability of Irreversible Hydrosols." By W. B. Hardy. 

 Communicated by F. H. Neville, F.E.S. 



IV. ''On the Effects of Strain on the Thermo-electric Qualities of 



Metals. Part II." By Dr. Magnus Maclean. Communi- 

 cated by Lord Kelvin, F.E.S. 



y. "On the Periodicity in the Electric Touch of Chemical Elements. 

 Preliminary Notice." By Professor Jagadis Chunder Bose. 

 Commimicated by Lord Eayleigh, F.E.S. 



* ' Phil. Mag./ vol. 45, p. 216 (1898). 



