128 



«■ KNOWLEDGE ♦ 



[Marco 2, 1883. 



li^ure just spoken of, l>ut no otlier comet is known to have 

 shown anything of the kind. It is not to he confounded 

 \vith the sunward jets sometimes ejected l)y cometary 

 nuclei, nor did it at all resemble the anomalous tail, 

 directed toward the sun, shown by Pechiile's comet (in 

 December, 1880), in addition to its ordinary tail. 



On Oct. 9, Schmidt, of Athens, announced the discovery 

 of a small companion comet, i° south-west of the large one, 

 and mo^-ing parallel with it. So far as we know, no one 

 else has observed this companion, though it was carefully 

 looked for at Washington, Princeton, and elsewhere. On 

 Oct 21, however, Mr. Brooks, of Phelps, New York, ob- 

 served either the same or another one, some 8° south and east 

 from the large comet. Like Schmidt's companion, it was 

 very faint (though large), and we have seen no observa- 

 tions of it from other sources. We have no means of 

 ascertaining whether these attendants accompanied the 

 comet on its way to the sun as separate objects, or whether 

 they are fragments detached from the main body. 



Mr. Brooks seems to think that the nebulous mass 

 ol)served by him was in some way connected with the faint 

 envelope and streamer just spoken of, which is not un- 

 likely. 



(To he C07ilinued.) 



THE CHEMISTRY OF COOKERY. 



By W. Mattieu Williams. 



LET us now make practical application of the laws of 

 albumen coagulation that were demonstrated in the 

 test-tube experiment. The non-professional student may 

 do this at the breakfast fireside. The apparatus required 

 is a saucepan large enough for boiling a pint of water — the 

 materials, two eggs. 



Cook the first in the orthodox manner by keeping it in 

 boiling water three and a half minutes. Then place the 

 second in this same boiling water ; but, instead of keeping 

 the saucepan over the fire, place it on the hearth and leave 

 it there, with the egg in it, about ten minutes or more. A 

 still better way of making the comparative experiment is 

 to use, for the second egg, a water-bath, or bain-marie of 

 the French scientific cook ; a vessel immersed in boiling, 

 or nearly boiling water, like a glue pot, and therefore not 

 quite so hot as its source of heat. In this case a thermo- 

 meter should be used, and the water surrounding the egg 

 be kept at or near 180° Fahr. Time of immersion about 

 ten minutes or more. 



A comparison of results will show that the egg that has 

 been cooked at a t^inperature of more than 30" below the 

 boiling point of , water is tender and delicate, evenly so 



throughout, no part being hard while another part is semi- 

 raw and sliniy. 



I said " ten minutes or more," because, when thus 

 cooked, a prolonged 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 attained when kept at 160° about twenty minutes. 

 The 180° is above-named because the rising of the tem- 

 perature 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, be- 

 sides 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 following experiment. At 10.30 p.m. I placed a new- 

 laid egg in a covered stoneware 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 chemists, viz., that the yolk coagulates firmly at a lower 

 temperature than the white. Whether this is due to a 

 different condition of the albumen itself or the action of 

 the other constituents on the albumen, requires further 

 research to determine. 



When eggs are cooked in the ordinary way, the 

 31 minutes' immersion is Lnsufiicient 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 " Nor- 

 wegian" cooking apparatus, wherein fowls, &c., are cooked 

 as the eggs were in my hat^case. 



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

 in a definitely-organised condition. It is distributed 

 between the fibres 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, ex- 

 cepting 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. 



Existing thus in a liquid state in our ordinary flesh 

 meats, it is liable to be wasted in the course of cookery, 

 especially if the cook has only received the customary 

 technical education and remains in technological ignorance. 



To illustrate this, let us suppose that a leg of mutton, a 

 slice of cod, or a piece of salmon is to be cooked in water, 

 " boiled," as the cook says. Keeping in mind the results 

 of the previously-described experiments on the egg-albumen, 

 and also the fact that in its liquid state albumen is dif- 

 fusible in water, the reader may now stand as scientific 

 umpire in answering the question whether the fish or the 

 flesh should be put in hot water at once, or in cold water, 



