January loth, 1922.] Proceedings. xiii. 



held at 3-15 p.m. Short Illustrated Addresses were given by 

 the President, on " Infant Birds "; and by Mr. John Allan, on 

 •' Soap Bubbles." 



Mr. and Mrs. R. H. Clayton entertained the guests to tea, in 

 the Common Room, at 4-0 p.m. 



The President, in his Address on " Infant Birds,'*^ 

 pointed out that, as a general rule, the young of birds which 

 made elaborate nests hatch at an earlier stage than those which 

 make little or no nest. The young are therefore more dependent 

 upon parental care until they are able to ^y. Ground nesting 

 birds, as a rule, are clothed in thick down and can run and feed 

 themselves immediately they leave the shell. He showed the 

 great difference in the plumages of young birds and those of 

 their parents, illustrating his remarks by photographs of the 

 greenfinch, sparrow, lapwing, sheld-duck, herring- and black- 

 headed gulls, nightjar, owls and cuckoo. 



Mr. John Allan explained the nature and demonstrated the 

 formation of " Soap Bubbles." The skins of liquids, he 

 said, were of different strengths : that of plain water is equiva- 

 lent to a weight of about 3I grains to the inch ; that of a soap 

 solution about one-third of this. Something like two million 

 thicknesses of the black portion of a bubble which he blew and 

 deposited on a ring would have to be placed upon each other 

 to make a thickness of one inch. It is this skin upon water 

 which enables such things as needles and pieces of tin to be 

 floated upon it, and the lecturer demonstrated this by floating 

 a flat piece of tin in a vessel of water, and propelling the tin 

 along with a piece of camphor. 



The efiect of force upon liquids and bubbles, making them 

 occupy the least possible space, was described by Mr. Allan; 

 as also was the refraction of rays of light through a soap bubble,, 

 causing the various colours observed. 



General Meeting, January loth, 1922. 



Mr. T. A. Coward, M.Sc, F.Z.S., F.E.S. (President), in the 



Chair. 



The following were elected Ordinary Members of the Society : 



Harold Tunley, B.Sc. (London), Scientist, The Manchester Grammar 

 School, Manchester. Gladys Clegg, M.Sc. (Liverpool), Research Assistant 

 in Botany, The Shirley Institute, East Didshury, Manchester. Kenneth 

 M. Smith, A.R.C.S., Senior Lecturer in Agricultural Entomology, The 

 University, Manchester. E. Holmes Smith, B.Sc. (Edinburgh), Senior 

 Lecturer in Agricultural Botany, The University, Manchester. 



