We have learned about baking, or cooking by dry, confined heat, and now we are to learn about cooking in a boiling liquid. This is the most common form of cooking, and water is the liquid usually employed.

Nearly every kind of food needs the action of water, or some other liquid, combined with heat, to cook it in the best manner.

Some seeds and grains, when fully grown, lose by the ripening process nearly all the water that was in them, and become very hard. They need to absorb a large amount of water in cooking to replace that which they have lost.

Other foods contain so much water that simply heating them cooks them sufficiently, while still others are improved by having the water they contain taken away

Some foods have flavors which are affected by the temperature of the water and the length of time they remain in it.

To understand the different effects of cold water and boiling water upon food, and also the time required for cooking in water, we need first to learn about boiling water. When we cook in boiling water, we really cook the water first; that is, we heat or boil it.

We will put a cupful of cold water in a saucepan over the fire, and see what happens. When it becomes so hot that we cannot bear the fingers in it we will take the temperature. This is scalding hot water. Soon we see tiny bubbles forming on the edges and bottom of the pan. This is the air in the water which expands by the heat. These air bubbles disappear as they reach the colder water near the top, and the cold water being heavier goes to the bottom. This makes a slight motion in the water which we call simmering, and which is often mistaken for boiling. Water simmers at about 180°.

After a while all the water is very hot, that nearer the bottom is changed into steam, large bubbles of steam rise rapidly and soon break above the surface, making quite a commotion or bubbling all over the top, and we say " the water boils."

We take the temperature, and find it boils at 212°. As the bubbles break the steam escapes, and when it comes in contact with the cold air above and outside the kettle it is changed, or condensed, into a fine mist. We call this mist steam, but the real steam is invisible.

Thus we learn that boiling is the changing of water or liquid into steam by the action of heat sufficient to cause commotion or bubbling on the surface.

Any solid must first be melted into a liquid before it can boil. We do not really boil our potatoes; we cook them in boiling water.

After boiling the water some time we take the temperature again, and find the water is no hotter than 212°. We increase the fire to make the water boil faster, and the force of the steam lifts the cover, and the water runs over and spatters the stove; but we find the water is no hotter. The excess of heat escapes in the steam, and in ordinary kettles it is impossible to retain the whole of it.

We cover the kettle, and some of the steam condenses into water on the inside of the cover, drops back again into the kettle, and gives up its heat. So although we do not gain any greater degree of heat by boiling rapidly, yet by keeping the cover on more of the heat is kept inside. The steam, as it changes from a vapor to a liquid, gives back the heat that it has, and by keeping in the steam we can economize heat.

We cool a portion of the boiling water, and find it tastes flat. This is because the gases, or air, which gave it a fresh taste have escaped.

If we let the water all boil away, or be changed into steam, we find only a rim or deposit of brown scum on the edge of the pan.

We learn by this experiment in cooking or boiling water That it boils at 212°, or when it bubbles all over the top;

That when once it boils all over it becomes no hotter, and fuel and heat are wasted when it boils at a galloping rate;

That the kettle should never be so full that the water, as it expands in heating, will boil over;

That it loses its freshness by long boiling, and should be used at once;

That it boils away faster if uncovered ;

That in time it will all evaporate and pass off as steam, and more must be added as needed;

And, lastly, that the water leaves a deposit on the kettle, which, if not removed, will in time affect the taste of the water.

These are only a few of the many facts to be learned about boiling water, but they are sufficient for our lesson.1

1 Water boils at a higher temperature when there is sugar or salt or anything in it to increase its density.

Water boils at a lower temperature when the pressure of the air upon the water is diminished. Before a rain the pressure of the air is lessened, because the air when filled with vapor is lighter. Things burn on more quickly at such a time because the water evaporates more rapidly. The pressure of the air is less the higher we ascend above the level of the sea, and at an elevation of 14,150 feet water boils at 188.6°. Cooking in boiling water requires a much longer time, therefore, in mountainous regions, for the water boils so quickly that it has less heat than at lower altitudes, where it is subject to greater pressure.

We will take for our experiment to-day some foods which contain starch and albumen, and see what effect cold water or boiling water has upon them. In this way we learn how to cook our food in water.