40 PHILOSOPHICAL TRANSACTIONS. [anNO 1/13. 



An Expeiiment on the Proportions of the Ascent of Spirit of fflne between two 

 Glass PlaneSf whose Surfaces were placed at certain different Distances from 

 each other. By the late Mr. Fr. Hauhshee, F.R.S. N*' 337, art. 12, p. 151. 



I took two clean glass planes, about 6 inches long, and 2 inches broad, and 

 separated them at each end by 32 pieces of brass plate, whose thickness, when 

 laid on one another, and pressed together by screws, made a distance between 

 the planes equal to -rV of an inch. Being thus prepared, I plunged one end of 

 them into some tinged spirit of wine: and after wetting the inward surfaces of 

 the planes with it, by declining the upper end, I set them upright ; and found 

 that the surface of the wine between them remained higher than the surface of 

 the wine on their outsides, by about -^ of an inch. After this, I reduced the 

 distances of the planes to half the former, by taking away l6 of the brass plates 

 from each end of them; then being plunged into the liquid, and used in all 

 respects as before, I found the spirit to stand between the planes just double 

 the height it stood at in the former trial. Again removing half the number of 

 brass pieces, leaving only 8 of them at each end, and using them as before, 

 the spirit rose between them to a height just double to that in the foregoing 

 trial. Thus from 8 I reduced them to 4 pieces at each end of the planes; then 

 again the spirit was seen to remain suspended at twice the last observed height. 

 In this last trial the planes were distant from each other only -p^ of ian inch ! 

 nearer than that I could make no certain measure; but I suppose the forecited 

 experiments are sufficient to ground a calculation on, even of the nearest 

 approximations. 



Some further Experiments ^ showing the Ascent of Water between two Glass 

 Planes in an Hyperbolic Curve. By the late Mr. Fr. HauksheCi F. R. S. 

 N°337, art. 13, p. 153. 



The figure of the hyperbolic curve, formed by the ascending of water betwieen 

 two square glass planes, as mentioned Philos. Trans. N° 336, gave me occasion 

 to make some further inquiries; and by many experiments I find, that the 

 same curve holds in all directions of the planes, the asymptotes being always 

 the one the surface of the water, and the other a line drawn along the touching 

 sides. Thus, when the touching sides were plunged under the surface of the 

 water, and the angle c was depressed and made to remain lower than the angle 

 a, as in fig. 1, pi. 2, then would be produced such an oblique curve as shown 

 in that figure. In all the several schemes, represented fig. 1, 2, 3, 4, 5, 6, 7, 

 8, ab represents the surface of the water on the outside of the planes, and ac 

 the touching sides of the same. Now, though the curve dd rises between the 



