LECT. XI. ACTION OF CALORIC. 223 



equivalent to the effect of a fall of 29-6 of the centigrade 

 scale [=53-28 of Fahr.f 



* There is, I suspect, a typographical error in one, at least, of the 

 temperatures referred to. Captain Parry (Journal of a Voyage for the 

 Discovery of a North-West Passage, 1821, p. 145,) alluding to a tempe- 

 rature of 55 Fahr. [== 48-3 centig.] observes that " not the slightest 

 inconvenience was suffered, from exposuse to the open air, by a person 

 well clothed, as long as the weather was perfectly calm ; but in walking 

 against a very light air of wind, a smarting sensation was experienced all 

 over the face, accompanied by a pain in the middle of the forehead, which 

 soon became rather severe." Is this the passage to which Matteucci re- 

 fers ? J. P. 



