Part 51 (2/2)

What is a Microphone?

This instrument is a variety of telephone by reat distance It consists of a s a weak current of electricity, a telephone for the receiving instru instruas carbon with the ends set loosely in blocks of the salued into a wooden base board This instrument is connected with the battery and the telephone So wonderfully sensitive is it, that the ticking of a watch, the walking of a fly across a board, or the brush of a cah it be hundreds of aphone?

It is a substitute for the ear and speaking trumpet It consists of three paper funnels placed side by side The two larger ones are about 6 feet 8 inches long and 27-1/2 inches in diameter, and are each provided with a flexible tube, the ends of which are held to the ear

The centre funnel, which is used as a speaking-trumpet, does not differ er and has a larger bell aphone, can, without other apparatus, carry on a conversation at a distance of one and a half or two miles

What is the Tasimeter?

It is an instruree of heat, and is mostly used in astrono froenious instrument, the invention of Prof Siemens of London, enables those on board of shi+ps to read from an index the depths of the ocean beneath the to which a heavy piece of ht to which the latter is subject in consequence of the variations of attractive force (the deeper the ocean the sistered on a scale by the indicator that is in connection with the steel spring

What is an Ane the velocity and force of the wind, and by which storms, at a distance, can be predicted

What is a Chronometer?

A time-piece of delicate and exact construction, chiefly eators It differs only fro so much influenced by heat and cold, and consequently in its accuracy in giving the time

CHAPTER XX

LIGHT, LIME LIGHT, MAGNESIUM LIGHT, ELECTRIC LIGHT, RAINBOW, PRISM, SPECTRUM, COLORS, PHOTOGRAPHY, CAMERA OBSCURA, STEREOSCOPE, KALEIDOSCOPE

Do you know soht is a mere form of vibration like sound, and like sound it requires so, and some medium to carry this vibration as air carries sound

Is not the air this medium?

No, it is supposed that there is an elastic fluid called ”ether” which pervades all space and matter, and if the molecules of a body are inthis ether in motion The ht according to its velocity

What sources of light do you know?

We are told that the principal source of light on earth is the sun, either directly with its own bea us with coas, candles, and ht and heat when burning are but sending forth in another form the rays of the sun which were stored up in nature's econoht is the result of cheht A third source of light is phosphorescence, as we see it in the gloorm and fireflies