Q. Why can they impart no extra heat after they boil?
A. Because all extra heat is spent in making steam. Hence water will not boil a vessel of water immersed in it, because it cannot impart to it 212 degs. of heat: but brine will, because it can impart more than 212 degs. of heat, without being converted itself into steam.
| Ether boils at | 104 degs. |
| Alcohol boils at | 173-1/2 degs. |
| Water boils at | 212 degs. |
| Water with one-fifth salt at | 219 degs. |
| Syrup boils at | 221 degs. |
| Oil of turpentine at | 304 degs. |
| Sulphuric acid at | 472 degs. |
| Linseed oil at | 640 degs. |
| &c. &c. |
Any liquid which boils at a lower degree can be made to boil if immersed in a liquid which boils at a higher degree. Thus a cup of ether can be made to boil in a saucepan of water. A cup of water in a saucepan of brine or syrup. But a cup of water will not boil if immersed in ether; nor a cup of syrup in water.
Q. Why are clouds higher on a fine day?
A. 1st—Because the air (expanded by heat) drives them higher up: and
2ndly—The clouds themselves are lighter, and therefore more buoyant.
Q. Why are the clouds lighter on a fine day?
A. Because their mists are either absorbed by the dry air, or vapourized by the hot sun.
Q. Why is a cup put topsy-turvy into a fruit-pie?