Light, at what rate does the light of the stars travel, 547 Light, why does it tarnish silver, 553 Light, why does it affect colours, 554 Light, why can pictures be taken by the sun's rays, 555 Light, when does it scorch plants, 558 Lightning, what is the cause of, 580 Lightning, why does it sometimes become zigzag, 586 Lightning, why is it sometimes forked, 587 LESSON XLVI. Lightning, why is it sometimes like a lurid sheet, 588 Lightning, when is the flash straight, 587 Lightning, when does the flash appear blue, 591 Lightning, why is it sometimes red, at others blue, yellow, or white, 592 Lightning, does it ever pass from the earth to the clouds, 593 Lightning, does it pass from the clouds to the earth, 594 Lightning, what is the force of, 595 Lightning, why is it dangerous to stand near a tree during a storm, 596 Lightning, why is it dangerous to sit near a fire during a storm, 598 Lightning, why is it dangerous to be near water during a storm, 599 Lightning, are iron houses dangerous, 600 Lightning, why does it seize upon bell wires, &c., 601 Lightning, are umbrellas with steel frames dangerous, 603 Lightning, are iron bedsteads dangerous, 604 Lightning, what is the safest situation during a storm, 606 Lightning-conductors, do they attract electricity, 608 LESSON XLVII. Lightning-conductors, which is the best metal for, 610 Lightning-conductors, why have they sometimes been found ineffective, 609 Lightning-conductors, why should large buildings have several, 611 Lightning-conductors, why should they have several branches penetrating the earth, 612 Lightning, through what distance will its light penetrate, 622 Lightning, how may we calculate the distance of a storm, 623 Lightning, why is the flash generally succeeded by heavy rain, 626 Lightning, why is a flash generally followed by a gust of wind, 627 Lime-kilns, why do persons viewed through the hot air of, appear distorted and tremulous, 483 Limpets, why is it difficult to strike them from rocks, 665 Lips, why are they red, 913 Liver, what effect has it upon the circulation, 901 Looking-glass, why, if you hold one at an angle towards the sun, will light be thrown in an opposite direction, 208 Loss, is there any such thing in the operations of nature, 270 LESSON XLVIII. Lungs, why are they placed in the chest of the body, 932 Magnetism, what is it, 633 Magnetic bodies, what are they, 634 Magpie, why is a single one said to foretell bad weather, 1118 Mahogany, what is it, 1190 Mahogany and other woods, why are there curious markings in, 1273 Man, why is he born without a covering, 1034 Man, why has he no external appendage to his mouth, 1037 Marbles, why do they revolve when propelled along the ground, 818 Marbles, why do striped appear to have more stripes when they are rolling than when at rest, 819