230 APPENDIX A. 



temperature, with a thermometric tube bent 

 round, and filled partly with mercury, 

 partly with water or alcohol. The mer- 

 cury will operate by its weight. The 

 upper part of the tube will be empty and 

 sealed, or fully open to the atmosphere. 



The bulb will be immersed in water the 

 temperature of which is to be measured. 

 . 7. If the tube is sealed, the upper part 

 must be cooled. 



The bulb might contain water, ether, or essence 

 of turpentine. 



If the tube is sealed, the tension of mercurial 

 vapor could be measured. 



Experiments on the constituent heat of vapors 

 by means of a barometric tube having two en- 

 larged bulbs. One of the bulbs may be im- 

 mersed in cold water, and the elevation of temper- 

 ature of this water will indicate the constituent 

 heat of the vapor. 



FIG. 8. 



