TABLE SHOWING CONDUCTIVITY AND SPECIFIC HEAT OF METALS
| Metal | Conductivity | Specific Heat | ||||||
| Silver | 1 | . | 00 | 0 | . | 0559 | ||
| Copper | . | 74 | . | 0923 | ||||
| Aluminum | . | 48 | . | 2022 | ||||
| Tin | . | 15 | . | 0509 | ||||
| Glass | . | 0017 | ||||||
| Silicon | . | 159 | at | 10° C. | ||||
| . | 2029 | at | 232° C. | |||||
| Nickel | . | 1084 | ||||||
| Tungsten | . | 035 | ||||||
CHAPTER XXVIII
Parers, Seeders, Grinders, Slicers, Etc.
198. Fruit and Vegetable Parers with Knives. Parers of the type with a knife have a fork-like device on which the fruit or vegetable is held while a knife blade, attached to a shaft governed by a spring, is pressed against the fruit or vegetable so that it cuts off a thin layer of the surface. Both the fruit and the knife are caused to rotate so that the whole surface of the sphere-like object will be covered by the blade of the knife during one or more revolutions of the wheel which operates them (Fig. 107). The knife is guarded so that it cuts only a thin layer from the outer surface of the fruit or vegetable. After the knife has made the complete journey over the surface, a device attached to the machine pushes the object from the fork so that a new one may be put in its place. Parers are quite complicated devices, but they have been perfected so that they are not clumsy, and some can core apples, stone peaches and slice the fruit.
Fig. 107. Parer.
Keep this type of machine dry so that it will not rust. Do not put it into water. Wipe off the blade of the knife and the fork when thru paring, so that the acid of the fruit will not discolor them and dull the knife. Keep the other parts dry and oiled. In time the spring governing the knife becomes weak and the machine will not do good work. This spring can be replaced on some machines. Parers are usually made of cheap material so that a new machine costs less than the repairs.