Cook one in the orthodox manner by keeping it in boiling water three-and-a-half minutes. Then place the other 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 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 thermometer should be used, and the water surrounding the egg be kept at or near 180° Fahr. Time of immersion about ten or twelve minutes. A comparison of results will show that the egg that has been cooked at a temperature 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 slimy. 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 twice as long without hardening. 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 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°; 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 perfection, delicately tender, but the yolk too hard. A third experiment of twelve hours, water at 200° on starting, gave a similar result as regards the state of the egg.