Popular Books on Natural Science

spaper public about affairs belonging to Physics is so great, that we are not surprised if such plans are spoken of as pract

tense light can be made artificially, as in the circumstance that the

y Trinity-church steeple, an intensely brilliant light be placed, as bright as can be produced by ga

running parallel to it, which we will call "B" street; and again, at a square's distance, a street parallel to "B" street, called "C" street; thus let us imagine seven streets in all-from "A" to "G"-running parallel, each at a square's distance from the other

understand this proportion we must pause a moment, for it is something not easily comprehended. We hope, however, to present it in such a shape, that

calculation and exper

es, as feeble. At three times the distance it does not shine three times as feeble, but three times three, that is nine times. In sci

to apply this

ty steeple shines so bright, that one is just able to rea

ker, because "B" street is twice the distance from Trinity church, and 2 × 2 = 4. Hence, if

ll be nine times darker there, for 3 × 3 = 9. This page in order to be rea

letters, according to the rule given above, would have to cover sixteen time

ance, we shall find thirty-six times darker; and, lastly, "G" street, seven times the distance from the light, will be forty-nine times darker than "A" str

ill then be sufficient light on "G" street for any newspaper to be read." Our friend will easily perceive, however, that

le to illuminate large public places with one light, but