FROM VARIOUS LIQUIDS, 265 



force of the ethereal vapour experimentally up as high aJ 

 212°, I contrived to efTedl it as follows: — Took a fyphon 

 tube fuch as defcribed above, only not quite fo I'ong, and 

 filled it in the manner above mentioned, with ether and 

 mercury, leaving about ten inches at the top of the tube 

 vacant; then having graduated that part into equal portions 

 of capacity, and dried it from ether, I drew out the end of 

 the tube to a capillary bore, cooled it again {o as to fuffer the 

 internal atmofpheric air to be of the proper denfity, and fud- 

 denly fealed the tube hermetically, thus inclofing air of a 

 known force in the graduated portion of the tube. Then, 

 putting that part of the tube containing ether into boiling 

 water, vapour was formed which forced the mercurial co- 

 lumn upwards and condenfed the confined air, till at length 

 an equilibrium took place. In this way I found 8.25 parts 

 of atmofpheric air of the force 29.5 were condenfed into 

 2.00, at the fame time a perpendicular column of 16 

 inches of mercury in addition prelTed upon the vapour. 

 Now the force of elaftic fluids being inverfely as the fpace, 

 we have 2.00 ; 29.5 : : 8.25 : 121.67 inches = the force 

 of the air within ; to which adding 16 inches, we obtain 137. 

 67 = the whole force fuftained by the vapour, meafured in 

 inches of mercury. The force of aqueous vapour, at the 

 fame diflance beyond the boiling point, or 322°, is equal to 

 137.28, per table. Thus it appears that in every part: of 

 4he fcale on which experiments have been made, the fame 

 law of force is obfervable with the vapour of ether as of 

 "Water. 



Experiments on Spirit of Wine. 



By boiling a fmall portion of the fpirit I ufed (about one Farce of vapor 

 cubic inch) in a phial, the thermometer flood at 119'' ^i^^i x^mtoi ^mt. 

 the commencement ; but by continuing the ebullition it ac- 

 quired a greater heat. The reafon is, the moft evaporable 

 part of the fpirit flies off during the procefs of heating, and 

 the refi; being a weaker compound, requires a flronger heat. 

 The true point of ebullition, I believe, was nearly 175°. — 

 The force of the vapour from this fpirit at the temperature of 

 212°, I found both by an open fyphon tube and one her- 

 metically fealed with atmofpheric air upon the mercurial co- 

 jumn, as with ether, to be equal to 5Sf inches of mercury. 



This 



