﻿172 Mr. C. Tomlinson's Historical Notes on some 



cohesion of the molecules of water being superior to a pressure 

 of three atmospheres, or a column of water of 30 metres. This 

 conclusion was arrived at by heating water in a chemically clean 

 tube in a bath of chloride of calcium as high as 138° C. 

 (280°'4 F.). The tube was 8 millims. in diameter (^ or ^V 

 inch), curved at an angle of 100° at the end where the water 

 was heated, the other end being furnished with two bulbs. The 

 water was first boiled so as to expel the air, and the extreme bulb 

 was then sealed. The portion of the column of water contained 

 in the short covered end was then put into the chloride-of-calcium 

 baths, of which there were four, one at 113° C, another at 121°, 

 a third at 128°, and a fourth at 132°, and this rose to 138°, at 

 which temperature the water suddenly burst into steam and con- 

 densed in the bulbs at the other end of the tube. 



24. From 1843 to 1863 it was considered a settled point in 

 physico-chemistry that, in proportion as water is deprived of air, 

 the character of its ebullition changes, becoming, as it does, 

 more and more abrupt, and boiling, like sulphuric acid, with fre- 

 quent soubresauts, and that between every two bursts of vapour 

 the water reaches a temperature above its boiling-point. To 

 effect this, according to Mr. Grove*, it is necessary that the 

 water be boiled in a tube with a narrow orifice, through which 

 the vapour issues ; if it be boiled in an open vessel, it continually 

 reabsorbs air and boils in the ordinary way. Mr. Grove de- 

 scribes an experiment in which water covered with oil was boiled 

 in a tube : the water also contained some wire, which was plati- 

 nized for the purpose of presenting more points for the ebullition 

 and for preventing soubresauts as much as possible. The boiling 

 was continued for hours and even for days ; the steam condensed 

 in the oil, and there was always found with it a minute bead of 

 nitrogen gas. It is contended that in this and another similar 

 experiment there was no pure boiling of water, no rupture of 

 cohesion of the molecules of water itself, but the water was boiled 

 by evaporation against a surface of gas. The conclusion is suffi- 

 ciently startling, viz. " that no one has yet seen the phenomenon 

 of pure water boiling, i. e. the disruption of the liquid particles 

 of the oxyhydrogen compound so as to produce vapour which 

 will, when condensed, be a water leaving no permanent gas." 



25. In 1861 M. Dufourf published an account of an experi- 

 ment in which water is said to have been raised to the tempera- 

 ture of 178° C. (352-4° F.) without boiling. For this purpose 

 the water, previously raised to 80° or 90° C, was suspended in 



* " On some Effects of Heat on Fluids/' Journal of the Chemical So- 

 ciety for 1863, 2nd series, vol. i. p. 263. 



t Archives de la Bibliotheque Universelle de Geneve. See also Ann. de 

 Chim. etdePhys. for 1863, ser. 3. vol. lxviii. p. 378. 



