388 London Philosophical Societij. 



best remedies fof defective vision, by Mr. Ware, was read 

 to the Society. 



%• In our last Volume, p. 73, in a Paper read before the Royal Society, 

 Jan. 23, " On the Structure of the Eyes of Man snd Birds, &c." it 

 was stated to have been by Mr. Campion. — The paper, we under- 

 stand, was by Mr. Philip Crampton, F.R.S. 



PHILOSOPHICAL SOCIETY OF LONDON. 



During this month the attention of the Society has been 

 directed to two lectures on the subject of Light and Heat, 

 by Mr. W. Henley. 



As the ancient theories of light and caloric had under- 

 gone so much discussion, and as other new ones had lately 

 been adopted and supported by several illustrious philoso- 

 phers, it became an interesting subject for the investigation 

 of the Society. In the lecture on Light Mr. H. gave a 

 very able analysis of the curious experiments of Mr. Ma- 

 ins, which confirmed his opinion of the polarity of light i 

 and after the most impartial review, he felt perfectly satis- 

 fied with the opinions of Sir Humphry Davy on this point. 



On the subject of Caloric he entered at much length, 

 and gave an abstract of the different theories, from that of 

 Zeno to those of the present time. He dwelt more parti- 

 cularly on the two theories maintained by the philosophers 

 ©f the present day, and his arguments were directed prin- 

 cipally against the material theory ; — that which supposes 

 caloric to be a peculiar and subtle fluid, capable of pervad- 

 ing, in a greater or lesser degree, every kind of matter, and 

 of counteracting, by its repulsive power, the attraction of 

 cohesion, an opinion adopted almost universally by the che- 

 mists. Mr. H. brought forward a number of facts which 

 it could not satisfactorily explain, but which favoured in the 

 most happy manner that hypothesis, which accounts for the 

 phaennmenaof heated bodies, by supposing the particles of 

 matter to be endowed with, a power of repulsion, and that 

 the effects of heat are only attributable to a rapid motion of 

 the minuter particles of matter, rather of a vibrating kind, 

 or of one round their own axis,- — an opinion now warmly 

 supported by Sir H. Davy. The theory was supported by 

 the lecturer by a number of well chosen experiments, which, 

 though not able perhaps to carry conviction to the sup- 

 porters of the material theory, are yet deserving of their 

 attention, as affording a proof of the impossibility of satis- 

 factorily accounting for all the phaenomena of heat by one 

 single theory. 



Irratum ia our last, page 311 — For Rev. J. Ni^hdasalef read //'', C-Pelli. 

 grew, Esq. Curator. 



KIRWA- 



