HYDROSTATICS. 187 



to half the height it would rise to in a tube ha- 

 ving its diameter equal to the distance of the 

 plates. 



NEWTON'S Optics, Book in. query 31. HAUY, Traite 

 Elemental de Physique, torn. i. 333. edit. 1806. 



a. When the plates make an angle with one another, 

 if they be immersed with the line of their intersec- 

 tion vertical, the water will ascend between them, 

 and form a hyperbola. 



b. LA PLACE caused experiments to be made with one 

 tube placed within another, so that their axes coin- 

 cided, and found that the water ascended in the 

 space between them only half as high as it would 

 have done in a single tube in which the diameter of 

 the bore was equal to the distance of the two tubes 

 from one another. HAUY, ibid. 



277. If a glass tube of a small bore be immer- 

 sed in mercury, the mercury does not rise within 

 the tube to the height at which it stands on the 

 outside : its surface within is convex, as it is also 

 without, all round the tube. 



The convex surface of the mercury within the tube, 

 intersects the surface of the tube at an angle of 

 40. See Dr YOUNG'S Lectures an Natural Philo- 

 sophy, vol. n. p. 649-, on the Cohesion of Fluids. 



278. If 



