Page:Popular Science Monthly Volume 23.djvu/234

222 temperature than 212° by any amount of violent boiling, the popular distinction between "simmering" and boiling, which is so obstinately maintained as a kitchen superstition, is demolished.

The experiment described in my last showed that immediately the bubbles of steam reach the surface of the water and break there—that is, when simmering commences—the thermometer reaches the boiling point, and that however violently the boiling may afterward occur, the thermometer rises no higher. Therefore, as a medium for heating the substance to be cooked, simmering water is just as effective as "walloping" water. There are exceptional operations of cookery, to be described hereafter, wherein useful mechanical work is done by violent boiling; but in all ordinary cookery, simmering is just as effective. The heat that is applied to do more than the smallest degree of simmering is simply wasted in converting water into useless steam. The amount of such waste may be easily estimated. To raise a given quantity of water from the freezing to the boiling point demands an amount of heat represented by 180° in Fahrenheit's thermometer, or 100° Centigrade. To convert this into steam, 990° Fahr. or 500° Cent, is necessary—just five and a half times as much.

On a properly-constructed hot-plate or sand-bath, a dozen saucepans may be kept at the true cooking temperature, with an expenditure of fuel commonly employed in England to "boil" one saucepan. In the great majority of so-called boiling operations, even simmering is unnecessary. Not only is a "boiled leg of mutton" not itself boiled, but even the water in which it is cooked should not be kept boiling, as we shall presently see.

In order to illustrate some of the changes which take place in the cooking of animal food, I will first take the simple case of cooking an egg by means of hot water. These changes are in this case easily visible and very simple, although the egg itself contains all the materials of a complete animal. Bones, muscles, viscera, brain, nerves, and feathers of the chicken all—are produced within the shell, nothing being added, and little or nothing taken away.

When we open a raw egg, we find, enveloped in a stoutish membrane, a quantity of glairy, slimy, viscous, colorless fluid, which, as everybody now knows, is called albumen, a Latin translation of its common name, "the white." Within the white of the egg is the yolk, largely composed of that same albumen, but with other constituents added—notably a peculiar oil. At present I will only consider the changes which cookery effects on the main constituent of the egg, merely adding that this same albumen is one of the most important, if not the one most important, material of animal food, and is represented by a corresponding nutritious constituent in vegetables.

We all know that when an egg has been immersed during a few minutes in boiling water, the colorless, slimy liquid is converted into the white solid to which it owes its name. This coagulation of