correspond. In other words he believed that the varying waves of electricity which passed along the connecting wire and into the coil which surrounded the magnet would cause the pull of the magnet on the thin iron plate to vary at the hearer's end precisely as it had done under the influence of the speaker's voice. This expectation proved to be well founded, and by the pull of the plate sound-waves were generated exactly similar to those which had originally set the apparatus in motion. 8. The telephone hears and speaks, may it not be made to write? This also has been accomplished. The thin plate of which we have spoken having a style attached to it makes what appears to be simply a line of pin points or dots more or less close to each other. But when the instrument is reversed, the grooves formerly made are again followed and exactly the same air-waves are excited which caused the pricking out of the dots, and consequently the same sounds are heard. 9. By means of the telephone a concert given in Philadelphia was at the same time enjoyed by an audience assembled in New York, at a distance of many miles. The sounds of the piano in Philadelphia were gathered up, and strengthened by what is termed a resonance-box in which a magnet was fixed, and in the usual way the music was conveyed to a corresponding instrument in the other city.-Compiled. Questions on the lesson:-By whom was the telephone invented? When? Of what two organs is it imitative? How is sound produced? What evidence is there that it is due to the vibrations of the sounding body? What is the effect of a sounding body on the air? What effect does the air in its turn produce? What kind of sounding body had Professor Bell first to get? What had to be done to the vibrations of this sensitive sounding body? What are the two facts relating to magnetism mentioned in par. 5? Explain the working of the instrument? SLEEP. 1 "He giveth his beloved sleep" (Psalm cxxvii. 2). 1. Of all the thoughts of God that are Along the psalmist's music deep, For gift or grace, surpassing this— "He giveth His beloved, sleep?" 2. What would we give to our beloved? 3. What do we give to our beloved? A little dust to overweep, And bitter memories to make The whole earth blasted for our sake: 4."Sleep soft, beloved!" we sometimes say, Sad dreams that through the eyelids creep: 5. O earth, so full of dreary noises! 1 Inserted by permission of Messrs. Smith, Elder, & Co God strikes a silence through you all, 6. His dews drop mutely on the hill, Though on its slope men sow and reap; He giveth His beloved, sleep. 7. Ay, men may wonder while they scan 8. For me, my heart that erst did go That sees through tears the mummers leap, 9. And friends, dear friends, when it shall be -Elizabeth Barrett Browning (1897–1861). THE PRECIOUSNESS OF TIME. 1. No regret for the irretrievable loss of fortune or of empire has ever been so deep as some have felt for the loss of their time. "All the treasures or glories of the world, if I possessed them, would I give to recover a few yearsone year-one month;" but vain, desponding, despairing, wish! 2. If the people of any tract or colony suffered disasters and losses in their valuable stores or plantations, whether by fire, tempest, or plunder, would their right policy be to be careless of the residue? So we-the more our days are beset by things that grievously invade them, disturb them, waste them, the more careful and zealous should we be to save and improve all that we can. Let not the enemy have to show all our most valuable substance as the wrecks, or the spoils of their warfare upon our life. 3. To this end, it is of the highest importance that time should be, if we may express it so, a REALITY in our perception and estimate; that we should verify it as an actual something, like a substance to which we can attach a positive value, and see it as wasting or as improved, as palpably as the contents of a granary, or as the precious metals. The unfortunate case with us is that time is apprehended but like air or rather like empty space, so that in wasting it we do not see that we are destroying or misusing a reality. 4. In losing, in wasting, a day or an hour, we have no perception like what we should have in burning or in throwing down a stream a valuable article that is tangible and visible, such as a useful implement, an instructive book, a quantity of corn or pieces of money. But a great object is to attain a perception of something like this. The simple way to attain this sense of time's reality is the habit of thinking what could be done in so much time. Time is equivalent to what could be done or gained in it. A portion of it thrown away, therefore, should be accounted of as just that thrown away, which could have been gained by improving it; that was contained in the time by possibility. 5. If a person were so foolish as to throw away a valuable piece of money into a pit or the sea, he does not, indeed, literally throw away anything but the metal, but virtually he throws away whatever best thing it would have purchased—it may be bread or clothing or refreshments or medicines for the sick, or an instructive book. |