Curiosities of Science. 191 



cooled down to a sub-red heat, or mercury is cooled from the 

 freezing point to zero, or far below. By the same rule, solid 

 mercury, say 50 below zero, may, in any climate or tempera- 

 ture of the atmosphere, be immediately warmed and melted by 

 being imbedded in a cake of ice. Scientific American. 



REPULSION BY HEAT. 



If water is poured upon an iron sieve, the wires of which 

 are made red-hot, it will not run through ; but on cooling, it 

 will pass through rapidly. M. Boutigny, pursuing this curious 

 inquiry, has proved that the moisture upon the skin is sufficient 

 to protect it from disorganisation if the arm is plunged into 

 baths of melted metal. The resistance of the surfaces is so great 

 that little elevation of temperature is experienced. Professor 

 Pliicker has stated, that by washing the arm with ether previ- 

 ously to plunging it into melted metal, the sensation produced 

 while in the molten mass is that of freezing coldness. R. 

 Hunt, F.R.S. 



PKOTECTION FKOM INTENSE HEAT. 



The singular power which the body possesses of resisting 

 great heats, and of breathing air of high temperatures, has at 

 various times excited popular wonder. In the last century 

 some curious experiments were made on this subject. Sir 

 Joseph Banks, Dr. Solauder, and Sir Charles Blagden, entered 

 a room in which the air had a temperature of 198 Fahr., and 

 remained ten minutes. Subsequently they entered the room 

 separately, when Dr. Solander found the heat 210, and Sir 

 Joseph 211, whilst their bodies preserved their natural degree 

 of heat. Whenever they breathed upon a thermometer, it sank 

 several degrees ; every inspiration gave coolness to their nostrils, 

 and their breath cooled their fingers when it reached them. Sir 

 Charles Blagden entered an apartment when the heat was 1 

 or 2 above 260, and remained eight minutes, mostly on the 

 coolest spot, where the heat was above 240. Though very hot, 

 Sir Charles felt no pain : during seven minutes his breathing 

 was good ; but he then felt an oppression in his lungs, and his 

 pulse was 144, double its ordinary quickness. To prove the 

 heat of the room, eggs and a beefsteak were placed upon a tin 

 frame near the thermometer, when in twenty minutes the eggs 

 were roasted hard, and in forty-seven minutes the steak was 

 dressed dry ; and when the air was put in motion by a pair of 

 bellows upon another steak, part of it was well done in thirteen 

 minutes. It is remarkable, that in these experiments the same 

 person who experienced no inconvenience from air heated to 

 211, could just bear rectified spirits of wine at ISO 3 , cooling oil 

 at 129", cooling water at 123, and cooling quicksilver at 117. 



