To connect by inserting a plug, as in a resistance box.

(a) A piece of metal with a handle and a somewhat tapered end, used to make connections by insertions between two plates or blocks of metal slightly separated and with grooves to receive it. (b) A plug or wedge with two metallic faces, insulated from each other with a separate wire connected to each one. [...]

A special form of Geissler tube designed for the production of stratification and for observing the effects produced in the space surrounding the negative electrode.

Contact arms projecting downwards from the motors, trucks, or bodies of electric street cars, which enter the underground conduit through the slot and carry contact pieces or brushes, to take the current for driving the motors from the leads within the conduit.

Finely divided platinum obtained by igniting platinum black, q.v., and also by igniting salts of platinum. It has considerable power of condensing or occluding oxygen. It will, if in good condition, set fire to a jet of hydrogen impinging upon it.

An alloy of 1 part platinum and 2 parts silver, used for resistance coils. Relative Resistance (silver annealed = 1 ),   16.21   microhms. Specific Resistance at 0°C. (32° F.),        24.39 Resistance of a wire, (a) 1 foot long, weighing 1 grain,         4.197   ohms. (b) 1 foot long, 1/1000 inch diameter,   146.70     “ [...]

Finely divided platinum. It is made by boiling a solution of platinic chloride with excess of sodium carbonate and a quantity of sugar, until the precipitate is perfectly black and the supernatant liquid is colorless. It seems to possess a great power of occluding oxygen gas. When heated to redness it becomes spongy platinum. The [...]

A metal; one of the elements; symbol, Pt; atomic weight, 197.4; equivalent, 49.35; valency, 4; specific gravity, 21.5. It is a conductor of electricity. The following data refer to the annealed metal at 0° C. (32° F.) Relative Resistance (Silver annealed = 1),   6.022 Specific Resistance,   9.057   microhms. Resistance of a wire, (a) 1 foot [...]

An alloy of copper, nickel, zinc in the proportions of German silver with 1 or 2 per cent of tungsten. It is used for resistances. It has a specific resistance (or resistance per centimeter cube) of about 34 microhms. Its percentage variation in resistance per degree C. (1.8° F.) is only about .021 per cent., [...]

The deposition of metal by electrolysis so as to coat the conducting surface of objects therewith. The full details of the many processes are very lengthy and cannot be given here. The general principle includes a battery or source of electric current. The object to be plated is connected to the negative terminal and is [...]