374 THE POPULAR SCIENCE MONTHLY. 



I said " ten minutes or more," because, when thus cooked, a pro- 

 longed exposure to the hot water does no mischief ; if the temperature 

 of 160 is not exceeded, it may remain for half an hour ; in fact, the 

 perfection of cooking, according to my experience (I always cook my 

 own eggs when I have the opportunity and can spare the time), is at- 

 tained when kept at 160 about twenty minutes. The 180 is above- 

 named because the rising of the temperature of the egg itself is due 

 to the difference between its own temperature and that of the water, 

 and, when that difference is very small, this takes place very slowly, 

 besides which the temperature of the water is, of course, lowered in 

 raising that of the cold egg. 



In order to test this principle severely, I have just made the fol- 

 lowing experiment : At 10.30 p. m. I placed a new-laid egg in a cov- 

 ered stone-ware jar, of about one pint capacity, and filled this with 

 boiling water ; then wrapped the jar in many folds of flannel so many 

 that, with the egg, they filled a hat-case in which I placed the bundle 

 and left it there until breakfast-time next morning, ten hours later. 



On unrolling, I found the water cooled down to 95, that the yolk 

 of the egg was hard, but the white only just solidified and much softer 

 than the yolk. On repeating the experiment, and leaving the egg in 

 its flannel coating for four hours, the temperature of the water was 

 123, and the egg in similar condition the white cooked in perfec- 

 tion, delicately tender, but the yolk too hard. A third experiment of 

 twelve hours, water at 200 on starting, gave similar result as regards 

 the state of the egg. 



This brings out a fact hitherto unknown to either cooks or chem- 

 ists, viz., that the yolk coagulates firmly at a lower temperature than 

 the white. Whether this is due to a different condition of the albu- 

 men itself or the action of the other constituents on the albumen, re- 

 quires further research to determine. 



When eggs are cooked in the ordinary way, the three and a half 

 minutes' immersion is insufficient to allow the heat to pass fully to the 

 middle of the egg, and therefore the white is subjected to a higher 

 temperature than the yolk. In my experiment there was time for a 

 practically uniform diffusion of the heat throughout. 



I shall describe hereafter what is called the " Norwegian " cooking 

 apparatus, wherein fowls, etc., are cooked as the eggs were in my hat-case. 



Albumen exists in flesh as one of its juices, rather than in a defi- 

 nitely organized condition. It is distributed between the fibers of the 

 lean (i. e., the muscles), and it lubricates the tissues generally, besides 

 being an important constituent of the blood itself of that portion of 

 the blood which remains liquid when the blood is dead, i. e., the serum. 

 As blood is not an ordinary article of food, excepting in the form of 

 " black-puddings," its albumen need not be here considered, nor the 

 debated question of whether its albumen is identical with the albumen 

 of the flesh. 





