PROCEEDINGS OF THE SOCIETY. 381 



the members of the Society that I have in my possession a communi- 

 cation forwarded to the Secretary, Prof. D. S. Kellicott, from the 

 Eoyal Microscopical Society, hearing date December 17th, 1884, with 

 an enclosed cheque for five guineas, as the first donation to the 

 Eobert B. Tolles Memorial Fund. That this evidence of appreciation 

 of the labours of Mr. Tolles, and of the work in which the American 

 Society is engaged, on the part of the Eoyal Society, will be keenly 

 appreciated by the members of this Society, and give an impetus to 

 the subscriptions to the funds referred to above, there can be no 

 question." 



Mr. Gr. D. Brown's letter was read as follows : — " In the current 

 number of the Journal, in a review of Mr. Busk's ' Eeport on the 

 ' Challenger ' Polyzoa,' it is stated that the use of the chitinous element 

 as an aid in the classification and descriptive geology of the Polyzoa 

 is entirely due to Mr. Busk. Allow me to call attention to Mr. 

 Busk's first mention of the subject — viz, in the Journal of the 

 Linnean Society, Zoology, vol. xv. (1881) p. 357. In this paper he 

 adopts and developes the facts corroborating the opinion of the 

 importance of these organs in this connection ; but he himself 

 states that he is indebted for the suggestion to a paper by Mr. A. 

 W. Waters in the Proceedings of the Literary and Philosophical 

 Association of Manchester, 1878." 



Mr. Crisp said that undoubtedly Mr. Waters should have the 

 credit of priority as acknowledged by Mr. Busk. The review in 

 question, however, was written by so eminent an authority (Prof. 

 Allman) that it had been printed without the thought that any 

 correction could be required. 



Dr. Ord exhibited and described some objects illustrating the 

 erosion of the surface of glass when exposed to the action of carbonate 

 of lime and a colloid. From experiments made by Mr. George 

 Eainy, it seemed that when lime was deposited upon glass in the 

 presence of a colloid, the globule it formed adhered so firmly as to 

 require removal by means of an acid. After this it was seen that 

 the surface of the glass was dimmed, and microscopical examination 

 showed that this was due to the presence of numerous little pits, 

 which evidently corresponded to the points of adhesion of the 

 globules, although no chemical substance capable of eroding glass 

 had been employed. Further experiments by the speaker were 

 detailed, showing that he had caused lime to be so deposited by 

 mixing carbonate of potash and chloride of lime in solutions of gum, 

 albumen, glycerin, and gelatin, and that in each case, except that of 

 gelatin, the dimming of the glass from the same cause had been 

 observed. Some slips of ivory and mother-o'-pearl were also eroded 

 in the same way by the glycerin solution, and it was inferred from 

 this that the substances mentioned had been eroded by purely 

 molecular action. The observation, it was considered, offered an 

 explanation of the effects of boring sponges upon shell and rock, 

 as well as of the phenomena of the similar removal of shell and 

 bone in the process of their remoulding. 



