246 Mr. Cajierojt on Vapour from Saline Water. 



XXXI. — The force of Vapour from Saline Water, as applied to Marine 

 Engines. By Paul Cameron. 



"Whex the following experiments were made, the barometer stood at 

 29'6, the temperature of the room being 62". 



I exposed a quantity of salt for three hours, and placed a theimometer 

 in it, until it indicated a temperature of 60". A glass globe was pro- 

 cured, two inches in diameter, with a stem ten inches long ; to the stem 

 was attached a scale, divided from 60° to 233°, representing the expan- 

 sion of pure and saturated water ; the glass globe and stem were filled 

 with pure water at 60°, the thermometer indicating the same heat. The 

 glass globe was then placed in a tin vessel, containing water, on the fire ; 

 the boiling point was marked on the scale attached to the stem, which is 

 divided so as to represent the scale of a thermometer: from this I was 

 enabled to determine the expansion of pure water, and to compare it with 

 water saturated with salt. 



The globe was again placed in the tin vessel over the fire till the 

 water boiled ; it was then quickly immersed in a tin vessel containing 

 four gills of water, at 60° ; in five minutes the water in the tin vessel 

 rose to 82° 5', and in forty minutes it fell to 78°. The glass globe, or 

 water thermometer, was filled with saturated water, and placed in the 

 tin vessel containing boiling water, and remained there till the saturated 

 water in the stem remained stationary at 220° ; it was then quickly im- 

 mersed in the tin vessel, containing water at 60°, and in five minutes 

 the water in the tin vessel rose to 82°, and in forty minutes it fell to 78°. 

 The water in the tin vessel was then saturated till its boiling point was 

 226°. The water thermometer was again placed in the tin vessel, and 

 stood at the boiling point, when its expansion was 233°; it was then 

 quickly immersed in water at 60°, and in five minutes the water rose 

 to 86°, in forty minutes it fell to 81°, and in one hour it fell to 78°. 



A tin vessel was procured, 3J inches diameter, 8 inches deep, contain- 

 ing four gills of water, with salt in solution : its boiling point previously 

 known to be 216°. Two thermometers were made to pass through a 

 stuffing bos in the cover, the scales being divided on the right hand side 

 to indicate the temperature, and on the left to indicate the pressure in 

 pounds on the square inch ; the bulb of one being immersed in the water, 

 the other placed in the space for the steam. On the top of the cover 

 were screwed two stop-cocks ; attached to one of ihem was a mercurial 

 gauge to indicate the pressure of the steam, the other used for blowing 

 off when requii-ed. The spirit lamp being then applied, and the water 

 made to boil, the thermometer, immersed in the water, indicated 216°, 

 and the one in the steam indicated 215°. At this stage of the experi- 

 ment, the mercurial guage began to move along with the thermometer ; 

 the steam was then allowed to blow off, and the water removed. 



An equal quantity of water with salt in solution, its boiling point being 

 221° 8', was then placed in the tin vessel over the spirit lamp ; when the 



