1835.] the Advancement of Science. 233 



ting substances in the form of prisms, in such a state of purity and 

 transparency as to see the lines. 



He also mentioned that he had already obtained approximate results 

 from oil of cassia, which agreed very nearly with theory. 



Mr. Whewell made some observations upon the phenomena of the 

 tides, and referred with great satisfaction to the observations at pre- 

 sent in progress of determination, along the shores of Great Britain, 

 upon the tides, and noticed the co-operation of the Dutch government 

 on this important subject. 



Thursdajf, I3th August. — No Lecture. 



Friday, 14th August. — The chairmen of the several Sections 

 gave an account of the various papers read during Thursday's and 

 Friday's Meetings. 



Professor Babbage then proceeded to offer some suggestions as to 

 the age of peat mosses, &c. He stated that the idea which he 

 hoped to see followed out, occurred to him as he was sitting under a 

 beautiful ash tree in the park of a friend with whom he was living. 

 The age of trees is known by the number of rings in the section of 

 them, and he remarked that many of those rings were of a large size, 

 while others were small. In conclusion, he (Professor Babbage) drew 

 from these variations, that where the rings were large the year was 

 favourable to vegetation ; while, if they were small, a less supply had 

 been afforded to the tree. The Professor, from these appearances, 

 w^as induced to believe, that means were provided, by the inspection 

 of these rings in flifferent trees, to ascertain different periods of time, 

 and the fertility or barrenness of the several years. 



Professor Sedgwick gave account of the labours of the Geological 

 Section. 



Saturday, IbthAugust. — A General Meeting was held at 2 o'clock, 

 when the Rev. Mr. Vernon Harcourt, as general secretary, addressed 

 the meeting. He apologized for the delay which had occurred, but 

 hoped it would be excused on account of the importance of the sub- 

 jects which had been discussed before the committee. Invitations 

 had been sent from Bristol, Liverpool, Birmingham, Manchester and 

 Newcastle, soliciting the Association to have its next meeting in those 

 several places, and what decided the selection in favour of Bristol, 

 was from that city having sent the first decided invitation. Every 

 kind of accommodation had been offered by the public and corporate 

 bodies. A difficulty then arose in selecting the officers of the Asso- 

 ciation in provincial towns, as they might not wish to undergo the 

 arduous labours and duties necessary to give effect to the proceedings, 

 but there did not appear to be a probability of any inconvenience 

 arising in the present instance. Mr. Harcourt then read the several 

 sums of money recommended by the Sections to be advanced for the 

 prosecution of scientific objects in various branches. — It had also been 

 determined to apply to Government to send out an expedition to the 

 Antartic Regions, for the purpose of discovering the Southern Mag- 

 netic Poles. He felt much gratification in announcing that the re- 

 sources of the Association had increased to a greater degree at this 

 than at any former meeting. He would not waste time in advocat- 

 ing the propriety of the system adopted by the Association, for that 

 system was the most efficacious iu imparting knowledge. Mr. Har- 



