Part 13 (2/2)

One of the great problereat distances By using a high voltage it may be sent hundreds of miles, but to use a current of that character in the cars, or shops, or hoerous

To meet this requirement transforh voltage, and deliver a current of low tension, and capable of being used anywhere with the ordinary motors

THE TRANSFORMER--This is an electrical device made up of a core or cores of thin sheet metal, around which is wound sets of insulated wires, one set being designed to receive the high voltage, and the other set to put out the low voltage, as described in a forinal output is a very high voltage, so that they will be stepped down, first froe to a lower, and then froe This is called the ”Step down”

transfores are generated

ELECTRIC FURNACES--The most important development of electricity in the direction of heat is its use in furnaces As before stated, an intense heat is capable of being generated by the electric current, so that it becoent to use for the treatment of refractory material

In furnaces of this kind the electric arc is the reat heat, the only difference being in the size of the apparatus The electric furnace is sih voltage, and such an arc is enclosed within a suitable oven of refractory material, which still further conserves the heat

WELDING BY ELECTRICITY--The next step is to use the high heat thus capable of being produced, to fuse ether It is a difficultto their bulk, and in addition i tons,offers a si the result, and in the doing of which it avoids the oxidizing action of the forging heat Instead of heating the pieces to be welded in a forge, as is now done, the ends to be united are sih the ends until they are in a soft condition, after which the parts are pressed together and united by the si of the plastic condition in which they are reduced by the high electric heat

This for , as the mass of the metal flows from one part or end to the other; the unity is a perfect one, and the advantage is that the metals can be kept in a se a perfect admixture of the two parts

With the ordinary forether without any delay, and at the least cooling must be reheated, or the joint will not be perfect

The s made, so that small articles, sheet reatest facility

CHAPTER XVIII

X-RAY, RADIUM, AND THE LIKE

The cas invisible to the human eye Its most effective work is done with bearapher uses the _Actinic_ rays Ordinary light is composed of the seven primary colors, of which the lowest in the scale is the red, and the highest to violet

Those below the red are called the Infra-red, and they are the Hertzian waves, or those used in wireless telegraphy Those above the violet are called Ultra-violet, and these are eh tension electric apparatus, which we have described in the chapter relating to wireless telegraphy; and the latter, called also the Roentgen rays, are generated by the Crookes'

Tube

This is a tube from which all the atmosphere has been extracted so that it is a practical vacuum Within this are placed electrodes so as to divert the action of the electrical discharge in a particular direction, and this light, when discharged, is of such a peculiar character that its discovery made a sensation in the scientific world

The reason for this great wonder was not in the fact that it projected a light, but because of its character Ordinary light, as we see it with the eye, is capable of being reflected, as e look into a le The X-ray will not reflect, but instead, pass directly through the glass

Then, ordinary light is capable of refraction This is shown by a ray of light bending as it passes through a glass of water, which is noticed when the light is at an angle to the surface