298 Bath Literary and Philosophical Society, 



chanical section, but a partial solution of continuity effected by 

 a vibratory motion. 



A member mentioned, that it had been publicly stated to be 

 in agitation, to contrive an apparatus by which 1000 pas lights 

 might at once be lighted by electrical means. Dr. Wilkinson 

 said that he did not deem any electrical apparatus at present 

 existing, competent in its highest state of excitement to pro- 

 duce such an effect. Su])posing the wires at each light one- 

 tenth of an inch distant from each other, the sum of all the 

 striking distances would be equal to one hundred inches, when a 

 thickness of plate of air to be broken through would require a 

 plate machine twenty feet in diameter, the glass part of which 

 could not be made for 100,000/. 



Dr. Wilkinson next directed the attention of the Society to 

 the application of his mechanical theory to the phaenomena of 

 light. He referred to tlie change of direction in a ball when 

 obliquely impelled out of air into water, and this he denominated 

 the refraction of the ball : however inclined, the ratio of devia- 

 tion is constant and uniform, depending on the difference of re- 

 sistance between the two media. The same principle Dr. W. 

 applied to the refraction of light. He considers all transparent 

 bodies with respect to light, the same as conductors with respect 

 to electricity ; that is, that the transparency depends on the uni- 

 versal diffusion of light with the transparent substance, and that 

 the first portion of light which is rendered apparent, is that 

 which previously existed in the substance impelled by the super- 

 induced quantity. 



April 7. A paper by Mr. Eckersall, on Locusts, having been 

 read, Mr. Chapman favoured the Society with some remarks in 

 opposition to the theory advanced in it by that gentleman. He 

 objected strongly to the supposition of Mr. E. that any ova 

 which might be conveyed into the stomach through the medium 

 of the locusts, when made use of as food, could afterwards force 

 their way to the skin, so as to form that cutaneous disease re- 

 presented by Diodorus Siculus and other writers, ancient as well 

 as modern, to be so very dreadful in its effects. The President 

 observed, that the cutaneous disease was more probably a con- 

 sequence of constitutional debility occasioned by the use of a 

 food containing so little no<nishment. 



The plan of a new drag or creeper, for searching for drowned 

 bodies, was presented to and approved of by the Society. It 

 consists of an iron rod, at lea'it six feet in length, divided into 

 three parts by two joints ; so that (the sides of rivers being ge- 

 nerally sloping) the two extremities of the rod may lie on either 

 bank, while the central part keeps its horizontal position on the 

 bed of the river ; to which rod are attached a number of creepers 



at 



