PROCEEDIXGS OF SOCIETIES. 181 



the crystals were characteristic of the particular metals or other 

 bodies fused with the borax. He then described at length the 

 beautiful effects produced, and gave theoretical explanations of 

 the phenomena. 



Before this paper was read the President stated that, as Major 

 Ross was about to leave London, he had consented to its being 

 brought before the Society, although the Council had not had an 

 opportunity of seeing it. Under these circumstances they would 

 exercise their discretion as to its publication. 



Mr. Brooke, F.R.S., remarked that the author had not 

 discriminated between two distinct phenomena in optics, refraction 

 and interference. He also referred to the attempts made by Newton 

 (to which Major Ross alluded) to explain the colours of films by 

 his corpuscular emission theory of light. The colours in Major 

 Ross's experiments were entirely produced by the well-known 

 action of tihns, and were perfectly accounted for by the undulatory 

 theory. 



Mr. Jabez Hogg thought that inferring the composition of 

 bodies from special forms of micro-crystals would easily lead to 

 error. Mr. Waddington had shown him specimens of micro- 

 crystals resembling those obtained in Dr. Guy's sublimations, and 

 showing the uncertainty of that class of evidence. 



Mr. Slack, wliile differing entirely from the theoretical portions 

 of Major Ross's paper, was of opinion that he had indicated an 

 interesting field of research, in which facts of importance might be 

 discovered. 



In reply to observations of Major Ross, Mr. Brooke explained 

 that, although various forms might be obtained from a crystallizable 

 body by crystallizing it under different conditions, they would all 

 be referred to the same system. 



Mr. Hogg then read a paper on " The Lingual Membrane of 

 Mollusca, and its Value in Classification." (See 'Trans.,' p. 93.) 



At the close of the above paper INIr. Hogg pointed out the ad- 

 vantage of mounting palates in glycerine. He found that Canada 

 balsam materially damaged the delicate portions of the structure. 



The Rev. Thos. H. Browne asked if Mr. Hogg thought 

 " lingual " a proper term for all the structures to which it was 

 applied. He considered that it should be restricted to palates in 

 which one portion was detached and capable of protrusion. The 

 best way to see the form of lingual teeth was to tear the palate 

 from the outside towards the centre. 



Mr. Hogg thought Huxley's term odontophore preferable to 

 lingual membrane. 



Soiree, Wednesday Evening, April 22nd. 



The invitations issued by the President and Council were 

 generally responded to, and the soiree was attended by upwards of 

 1300 visitors and Fellows. By the courtesy of the authorities 



