.58 RoyaL Society, 



was found by him to measure the other dimensions so accurately as 

 that by seven, or its multiples. Of such seventh parts there appear to 

 be twelve in the longitudinal extent of the back, and ninety-six in the 

 height of the whole body. 



f). ** On the Repulsive Power of Heat." By the Rev. Baden Powell, 

 M.A., F.R.S., Savilian Professor of Geometry in the University of 

 Oxford. 



The expansion of bodies by heat appearing to imply a mutual re- 

 pulsion of their particles, it becomes a question whether such repul- 

 sive power may not be excited by it between particles or masses of 

 matter, at sensible as well as insensible distances. After noticing the 

 partial investigations of this question by Libri, Fresnel, Saigey, and 

 Professor Forbes, the author describes the method he has employed 

 with a view to its solution, and which consisted in applying heat to 

 two lenses of glass, pressed together so as to exhibit the colours of 

 thin plates; the variation of the tints furnishing exact indications of 

 the most minute changes of distance between the surfaces, by what- 

 ever causes they may be produced. The conclusion he deduces from 

 his experiments, conducted on this plan, is that the separation of the 

 surfaces is of a different character, and is greater than can be accounted 

 for by the mere change of figure produced by the heat; and is therefore 

 in part to be ascribed to a real repulsive action between the surfaces of 

 the glasses derived from the power of heat. He also found, on trying 

 similar experiments with glass in contact with a metallic surface, that 

 the results were considerably influenced by the radiating power of the 

 latter ; the effect being increased when this power was greater, and 

 also by all other causes tending to the more rapid communication of 

 heat. This is still more apparent when the coloured rings are formed 

 in a thin plate of water interposed between the lenses, and where the 

 effects are independent of radiation. 



6. " Analysis of the Moira Brine Spring near Ashby-de~la-Zouch, 

 Leicestershire, with Researches on the Extraction of Bromine." By 

 Andrew Ure, M.D., F.R.S.* 



The water derived from the spring in question is raised by means 

 of a pump from the coal mines in the neighbourhood of Ashby-de-la- 

 Zouch, is much used as medicinal baths, and is also administered 

 internally, principally as a remedy for bronchocele and scrofulous 

 tumors. The result of the analysis made by the author, is that it 

 contains per gallon, grs. 



Bromide of sodium and magnesium 8* 



Chloride of calcium 85 1 -2 



magnesium 16* 



sodium 3700*5 



Protoxide of iron, a trace 



Solid contents 4575*7 



• See an abstract of Prof Daubeny's paper " On the occMrrence of 

 Iodine and Bromine in certain mineral waters of South Britain," in Phil. 

 M:ig. and .\nnals, N.S., vol. viii. pp. Gl, 62. 



