Mr. G. Gore on a new Gas-Furnace, 15 



blished that the deviations in the relations between the tempe- 

 rature and the tension of saturated vapours and the analogous 

 relations of permanent gases rest essentially on the fact that the 

 quantity of heat contained in vapours increases with the tempe- 

 rature. 



The similarity of the formulae which have been constructed 

 for the calculation of the tensions of vapours of different liquids 

 approaches identity, if we, in order to ascertain the coefficient 



a = , start with the boiling-point t° of each liquid, and the 



corresponding tension of 760 millims. We thus obtain the 

 equation 



alog 273 +* +r 

 pmm = 760X10 273+t , 



wherein, for equal distances r above or below the boiling-point of 

 different liquids, the logarithmic factor remains, it is true, not 

 exactly the same, but, with decreasing boiling-points, very gradu- 

 ally increases in the first case and decreases in the other. The cor- 

 responding values of a generally change in the opposite direction, 



whereby the logarithm a log Q remains constant forsmall 



differences of t. 



If this were exactly the case, different liquids at temperatures 

 equidistant above or below from their respective boiling-points 

 would have the same tension of vapour, — an experimental con- 

 clusion which was first expressed by Dalton. 



II. On a new Gas- Furnace for Experimental, Analytical, and 

 other purposes. By G. Gore, Esq.* 



BEING engaged some time ago in an investigation upon cer- 

 tain properties of fused substances, I required a furnace 

 by means of which I could obtain a temperature equal to the 

 fusing-point of cast iron, and have the fused substances perfectly 

 accessible to be manipulated upon for a continuous and length- 

 ened period of time without contact with impurities or with the 

 atmosphere, and without lowering their temperature sufficiently 

 to cause them to solidify. I wished also to obtain these condi- 

 tions by means of ordinary coal-gas and atmospheric air, without 

 the use of a bellows, blowing apparatus, or tall chimney, or the 

 aid of valves requiring frequent attention. 



* Communicated by the Author. 



