fy ndsBeleerd) 
On the Refraction and Polarization of Heat. By James D. Forsss, 
Esq., F. R. SS. L. & E., Professor of Natural Philosophy in the 
University of Edinburgh. 
(Read 5th and 19th January 1835.) 
§ 1. Some Miscellaneous Experiments with the Thermo-Multi- 
plier. § 2. On the Polarization of Heat by Tourmaline. 
§ 3. On the Polarization of Heat by Refraction and Re- 
flection. § 4. On the Depolarization and Double Refrac- 
tion of Heat. 
1. Tue experiments to be detailed in this paper, which chief- 
ly go to establish properties of heat wholly unlooked for, or only 
suspected to exist, having been made entirely by means of an in- 
strument of great delicacy—the thermo-multiplier of MM. No- 
pitt and Mettoyt, I shall premise some account of its application 
to the investigation of some more familiar modes of action. 
§ 1. Miscellaneous Experiments. 
2. We could hardly quote a stronger proof of the rapid and 
unexpected advances which enlarged theory may produce in 
practice, than by referring to the employment of thermo-electric 
action, discovered a few years since by SrEBeck, to the mea- 
surement of heat, with a degree of accuracy and facility which, 
perhaps, no thermometer has ever attained. Such is the prin- 
ciple of the thermo-multiplier of Nosi11 and Meuxonr. It is well 
known, that when two metals (and especially bismuth and anti- 
mony) are soldered together, and the point of union heated, an 
electric current is established from the one metal to the other, 
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