ON THE EFFECTS OP HEAT. 105 



nated with carbonic acid. After the water had boiled for 

 sometime, the albumen appeared perfectly white, and was 

 nearly solid ; (it does not become perfectly so till cold). 

 In this state it was removed from the fire, but I was sur- 

 prised to find its bulk increased, rather than diminished, 

 for its surface was very globular. I had not however kept it 

 out of the water more than a minute, before it had sunk 

 considerably, so that its surface was now become concave. 

 If in this state it had been suffered to cool, it would cer- 

 tainly have occupied considerably less space, than when 

 fluid; notwithstanding the extrication of the bubbles of 

 gas, which never rose to the surface, but always continued 

 mixed with the albumen. When it had cooled only a few 

 degrees, it was replaced upon the fire; its surface soon rose 

 again, and by continuing the heat, at last burst, and a 

 quajjtity of vapour made its escape. The albumen was 

 I10VV full of holes, occasioned either by the separation of gas, 

 or of aqueous vapour. From the experiments of Dr. 

 Bostock it appears, that the white of egg contains 80 pev 

 cent of water. Now when this circumstance is also taken 

 into consideration, I think no one would urge the coagula- 

 tion of albumen by heat as an objection to the foregoing 

 theory. From the experiments which I have just related, 

 jt appears exceedingly probable, that albumen contracts 

 during solidification, as is the case with most other bodies ; 

 and at any rate, the extrication of gas, and the quantity of 

 water which it contains, will easily account for the apparent 

 anomaly. 



It vciixy however still be objected, If heat causes other Objectiqa 

 bodies to become fluid, how can it be the cause of the co- f'^'*'"^' 

 agulation of albumen } I might reply, that the density of 

 the atmospheres, which surround tlie particles of albumen, 

 is too great, to permit the particles themselves to approach 

 ^ach other sufficiently near to produce a solid ; but that by 

 the addition of calpric, these atmospheres are equalized, 

 and thus the resistance to the motion, (and consequently to 

 the union,) of the particles is removed, or at least dimi- 

 nished. I do not however urge this reason, because I believe Answered. 

 it to be far more probable, that the albumen undergoes 

 some chemical change, by the application of heat ; and I 



think. 



