Philadelphia Manual Training School - US Yearbook (Philadelphia, PA)

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AN ESSAY ON ELECTRICITY. ' ELECTRICAL FACTS. HE object of the course in electricity at the Manual Training School is to familiarize the pupil with the use of the com- moner electrical apparatus. That my keen perception and ability to understand everything have enabled me to successfully manipulate all the instruments you will not doubt after reading this article. VVithout further preface I will at once proceed to give you the benefit of my Manual Training School experience. Qf course, electricity must be measured and weighed, just as you are weighed when you order a ton of coal and measured when you buy a pound of sugar. If you send an electric cur- rent of say, two ohms capacity through a wire, that wire con- tains what is known as a current of electricity. When an elec- tric current passes through a battery it can be detected by looking at it through what is called a Rheostat in electrical rectangles QI can't say electrical circles, because the most important of electrical instruments-the Grainstone Bridge-is rectangularj. The candle power of an ammeter can be found by multiplying the length of wire by the logarithm of a con- stant-o.OOO3281 5 the' result is always in volts, and is generally found to be 7.6. In this operation is used what is called a Potentiometer. - It is impossible to exercise too much caution in the handling of apparatus, and I would here advise all those who 'intend making electricity their future study to accustom themselves to putting everything in its place. Have separate nails on which to hang volts, amperes and ohms, as a mixture of them often causes trouble. Once the fall of potential on the Hoor of the testing room was so great as to cause Professor Thorpe to send up a request to leave off hammering. 78

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him just what I thought of such a miserly man, only it was to myself The next morning he wanted to borrow a quarter, but as I had bought a suit of clothes, paid my board hill and gave the rest to the poor out of the 5Oc., he whistled. The next day he discharged me for being altogether too bright, as I locked in the janitor for a customer. Boys, don't be lawyers, as the Hnancial returns are altogether too fat. A FELLOXV WHO Knows.

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You will Find by experience that Lockstone is Wrong in claim- ing that the tangent galvanometer will run the telephone. Even in silver-plating it is of no avail. The galvanometer on the Wall would often make the remark, in a sepulchral voice, More currantsf' Raisins were as near the desired article as anything we could find, so We stuffed several of them into the hole. The telegraph is an instrument for measuring the depth of plating on any article. f Inshoelators are for the measurement of current strength. The word indicates its origin, the second syllable is shoe, which articles are excellent inshoelators. It is important that electricians should remember that it is not the current strength which is most important, but the motive back of it -the electromotive force. A copper voltameter is an instrument used by policemen Q cops j when desiring to converse with others some distance off 'lt is based on the principle of the fulcrum and lever Qnow don't say you'1l leave her bel. And now, my last, but not least, admonition is that people wearing false teeth should always speak into the lower of any two speaking instruments, for if a set should fall into the upper one of them, exposure and disgrace are inevitable. 79'