May \lth, 19 19.] PROCEEDINGS. xvii, 



saturation. Further experiments on a large number of aqueous 

 solutions and binary mixtures, such as salol mixed with betol, con- 

 firmed the conclusion that a super-saturated solution passes at a 

 definite temperature into a condition (the labile state) in which 

 spontaneous crystallisation can be induced by mechanical means 

 whereas above this temperature (the metastable state) crystals only 

 grow by inoculation of the solution with crystalline germs. 



Crystals only appear along the line of scratch made by a clean 

 rod in a super-saturated solution if the solution is in the labile 

 state : in the metastable state the crystals only appear if the rod 

 is contaminated with crystal germs. 



The complete freezing point diagram of a binary mixture 

 therefore shows " supersolubility curves " or curves of spontaneous 

 crystallisation, in addition to the ordinary freezing point 

 curves and in the area between them the liquid is in the metastable 

 state. Mixtures of Monochloracetic Acid and Naphthalene led to 

 the determination of three supersolubility curves for Mono- 

 chloracetic Acid corresponding to the spontaneous crystallisation 

 of three different modifications of this substance. 



The difference between the rapidly growing needle in the 

 labile solution, and the slowly growing regular crystals when the 

 solution becomes metastable, was illustrated by drops of crystal- 

 lising solutions (especially potassium bi-chromate) viewed on the 

 screen with a projection microscope. 



Extraordinary General Meeting, May 13th, 191 9. 



The President, Professor G. Elliot Smith, M.A., M.D., F.R.S., 

 in the Chair. 



At this Extraodinary General Meeting, summoned in 

 accordance with the Articles of Association, the following 

 resolutions of the Council were submitted to the Society : — 



" The Council of the Literary and Philosophical Society 

 welcomes the proposal of the Chemical Club 'by 

 which the Club expresses its desire to become 

 merged in the Society and cordially approves that 

 proposal." 



"To enable the Club to fulfil its present obligations to 

 all its Members up to the close of their present 

 session (March 31st, 1920) the Council would agree 

 to all those Members having the use, during the 

 current year, of the Society's rooms and library on 

 the same terms as its own Members, and would give 

 permission to Members of the Club to attend the 

 Society's meetings, subject to the payment to the 



