78 VERTEBRATED ANIMALS. 



is a difference of 130 degrees, between that of the 

 atmosphere and that of the turkey. But the Black-cap* 

 titmouse, a little bird which passes its winters with us 

 is a much more extraordinary instance of the same 

 kind, on account of its diminutive size. This bird as it 

 flies, does not probably weigh more than half an ounce, 

 and yet small as it is, the vital action with which it is 

 endowed, is sufficient to maintain its temperature, 130 

 or 140 degrees, above that in which it is placed, and this 

 difference so far from inducing torpor, seems from the 

 cheerful and lively appearance of the little animal, to be 

 a temperature most agreeable to it. 



On the contrary, it is found by accurate experiments, 

 that the animal system is capable of resisting degrees of 

 heat in a much greater proportion above its own tem- 

 perature, than these are below. 



Origin of the experiments on the power of Man to 

 resist heat. A circumstance which happened in France, 

 in the year 1760, first led philosophers to make experi- 

 ments on the power of the human system to resist high 

 temperatures. Some gentlemen having occasion to use 

 a public oven for certain experiments on the day in 

 which bread had been baked in it, and wishing to ascer- 

 tain its temperature, a girl, one of the attendants at the 

 bakery, offered to go in, and mark the height of the mer- 

 cury with a pencil. The girl smiled at the hesitation of 

 the gentlemen to allow her to do so, and going into the 

 oven, marked the temperature at 260 of Fahrenheit. 

 Notwithstanding the anxiety they felt for this young sala- 

 mander, she declared to their astonishment, that she felt 

 no inconvenience from the heat, and insisted on staying 

 longer, and having remained ten minutes, the thermom- 

 eter then was found to stand at 288, that is, 76 above 

 the heat of boiling water, and 190 above the ordinary 

 temperature of the human system, which is 98. 



Experiments of Sir Charles Blagden and Dr. For- 

 dyce. The publication of these facts excited general 



What circumstance first led philosophers to make experiments on the 

 power of the human system to resist heat 1 How much higher was the 

 temperature of the oven than that of the ordinary human system ! 



