[Illustration:  A Tight-Fitting Cork Driven into a Cracked Faucet Converted It into an Emergency Plug]

emergency plug which prevented leakage until the proper fitting to take its place could be secured.  —­Contributed by James M. Kane, Doylestown, Pa.

** Automatic Electric Heat Regulator [344]

It is composed of a closed glass tube, A, Fig. 1, connected by means of a very small lead pipe, B, to another

[Illustration:  Heat Regulator]

glass tube, C, open at the bottom and having five pieces of platinum wire (1, 2, 3, 4 and 5), which project inside and outside of the tube, fused into one side.  This tube is plunged into an ebonite vessel of somewhat larger diameter, which is fastened to the base by a copper screw, E. The tube C is filled to a certain height with mercury and then petroleum.  The outer ends of the five platinum wires are soldered to ordinary copper wires and connections made to various points on a rheostat as shown.  The diagram, Fig. 2, shows how the connections to the supply current are made.  The apparatus operates as follows:  The tube is immersed in the matter to be heated, a liquid, for instance.  As

[Illustration:  Wiring Diagram Showing How the Connections to a Source of Current Supply are Made]

the temperature of this rises, the air expands and exerts pressure on the petroleum in the tube C so that the level of the mercury is lowered.  The current is thus compelled, as the platinum wires with the fall of the mercury are brought out of circuit, to pass through an increasing resistance, until, if necessary, the flow is entirely stopped when the mercury falls below the wire 5.

With this very simple apparatus the temperature can be kept constant within a 10-deg. limit, and it can be made much more sensitive by increasing the number of platinum wires and placing them closer together, and by filling the tube A with some very volatile substance, such as ether, for instance.  The petroleum above the mercury prevents sparking between the platinum wire and the mercury when the latter falls below anyone of them.

** Repairing a Washer on a Flush Valve [344]

When the rubber washer on the copper flush valve of a soil-basin tank becomes loose it can be set by pouring a small quantity of paraffin between the rubber and the copper while the valve is inverted, care being taken to have the rubber ring centered.  This makes

[Illustration:  Flush Valve]

a repair that will not allow a drop ot water to leak out of the tank.  —­Contributed by Frank Jermin, Alpena, Michigan.

** Cleaning Discolored Silver [344]

A very quick way to clean silver when it is not tarnished, but merely discolored, is to wash the articles in a weak solution of ammonia water.  This removes the black stains caused by sulphur in the air.  After cleaning them with the solution, they should be washed and polished in magnesia powder or with a cloth.  This method works well on silver spoons tarnished by eggs and can be used every day while other methods require much time and, therefore, cannot be used so often.