When it cools it becomes hard, but if before it is quite cold we plunge it into cold water a very perfect perlitic structure will arise in it.
Before commencing the mastication it is generally necessary to warm the apparatus by means of steam; but as the operation proceeds the heat produced requires to be moderated by streams of cold water flowing through channels provided for the purpose.
For first-degree burns, the child's parent can put a cold-water compress on the area or run cold water on it and cover it with a clean bandage for protection.
The automatic inlet of cold water to the hot water system from the main house tank or other source is controlled by a ball valve, which is so fixed as to allow the water to rise no more than an inch above the bottom of the tank, thus leaving the remainder of the space clear for expansion.
The supply from the cold water cistern enters the bottom of the cylinder, and thence travels by way of the return pipe to the boiler, where it is heated, and back through the flow pipe to the cylinder, which is thus soon filled with hot water.
