So much of cookery being effected by the application of heat, a sketch of the general laws of heat might be included in this introductory chapter, but for the necessary extent of the subject.
I omit it without compunction, having already written ‘A Simple Treatise on Heat,’ which is divested of technical difficulties by presenting simply the phenomena and laws of Nature without any artificial scholastic complications. Messrs. Chatto & Windus have brought out this little essay in a cheap form, and, in spite of the risk of being accused of puffing my own wares, I recommend its perusal to those who are earnestly studying the whole philosophy of cookery.
[CHAPTER II.]
THE BOILING OF WATER.
As this is one of the most rudimentary of the operations of cookery, and the most frequently performed, it naturally takes a first place in treating the subject.
Water is boiled in the kitchen for two distinct purposes: 1st, for the cooking of itself; 2nd, for the cooking of other things. A dissertation on the difference between raw water and cooked water may appear pedantic, but, as I shall presently show, it is considerable, very practical, and important.
The best way to study any physical subject is to examine it experimentally, but this is not always possible with everyday means. In this case, however, there is no difficulty.
Take a thin[1] glass vessel, such as a flask, or, better, one of the ‘beakers,’ or thin tumbler-shaped vessels, so largely used in chemical laboratories; partially fill it with ordinary household water, and then place it over the flame of a spirit-lamp, or Bunsen’s, or other smokeless gas-burner. Carefully watch the result, and the following will be observed: first of all, little bubbles will be formed, adhering to the sides of the glass, but ultimately rising to the surface, and there becoming dissipated by diffusion in the air.
This is not boiling, as may be proved by trying the temperature with the finger. What, then, is it?