24. 



January Jth^ i8gs- 



Robert Lloyd Patterson, Esq., J. P., F.L.S., President, in 

 the Chair. 



Mr. Joseph Barcroft, of King's College, Cambridge, gave a 

 Lecture on 



" THE PROPERTIES of the SURFACE OF LIQUIDS." 



The President, in introducing the lecturer said they were 

 assembled that evening to hear a lecture from Mr. Barcroft. 

 His subject sounded rather technical, but he was sure he would 

 make it very clear to them. 



Mr. Barcroft then proceeded with his lecture, and prefaced 

 his remarks by stating that, although the ti!:le of his lecture 

 appeared to be of a somewhat technical nature, he had really 

 chosen the subject because it was one the knowledge of which 

 enabled us to account for a great many phenomena to be seen 

 every day, hence one not without interest to those who took a 

 pleasure in investigating what they saw around them. The 

 fact that if the surface was not penetrated a needle may be made 

 to float upon water at once shows a difference between the 

 properties of the surface and those of the general mass of the 

 liquid. The difference was explained by a model, in which 

 each of the indistinguishable particles of molecules of which 

 the water was composed was represented by a marble, from 

 which it appeared that while a particle in the body of the water 

 was equally attracted by particles all round it, those at the 

 surface were only attracted downwards by those below them. 

 All around the hquid its bounding surface is as it were 

 compressing the water, and acts in fact just as though the water 

 were entirely enclosed in a distended bag of india-rubber. The 



