Mathematics and General Physics. S9l 



the quantity of rain registered under diiFerent circumstances of ob- 

 siervation. Mr Howard likewise made some observations. 



It was then moved by Dr Robinson, that the Section should re- 

 turn its thanks to Mr Pliillips for the careful manner in which he 

 had executed the task entrusted to him by the Association, and re- 

 quest him to continue his observations during another year, with 

 the view of obtaining such results as might furnish the means of 

 deciding on the theories that had been proposed for the explana- 

 tion of the phenomena. 



Mr Phillips thanked the meeting for the kind manner in which 

 his communication had been received, and professed his readiness 

 to comply with the request. Mr Phillips gave some further ac- 

 count of his mode of observation, with reference principally to the 

 remarks of Mr Howard. 



Professor Stevelly read a paper, entitled " An attempt to con- 

 nect some well known phenomena in Meteorology, with well esta- 

 blished physical principles." The questions discussed in this paper 

 were, — I. The nature, origin, and suspension of clouds, and the im- 

 mediate effect of their formation ; 2. The manner in which rain is 

 produced, and the immediate effect of its production ; 3. The man- 

 ner in which wind results from the formation of cloud and rain ; 4. 

 The origin of hail. 



Section B. — Chemistry and Mineralooy. 



The Chemical Section proceeded to consider the recommenda- 

 tions of the Sections of the former meetings, having reference to 

 Mineralogy and Crystallography. 



Mr Whewell made a communication on the progress of the in- 

 quiries entrusted to Prof. Miller on the forms of crystals, and to 

 the Committee appointed to examine the subject of isomorphism. 

 He stated that the German chemists and cr y stall ographers are ar- 

 dently engaged on this important subject. In regard to the pro- 

 perties of substances similar in constitution and form, he directed 

 the attention of the meeting to the important fact, that the optical 

 properties are often very different in substances considered to be of 

 the same species. And on this subject reference was made to the 

 case of topaz, on which some discussion took place, chiefly on the 

 observations made as to the relation of their optical axes at different 

 temperatures. 



A paper was read by Dr Charles Williams, On a New Law of 

 Combustion. In this communication the author shewed, that many 



