Q. Why is the middle story of a house safest in a thunder-storm?
A. Because (even if the fluid struck the house), its strength would be exhausted before it reached the middle story.
Q. Why is the middle of the room more safe, than any other part of it, in a thunder-storm?
A. Because, if the lightning came into the room at all, it would come down the chimney or walls of the room; and therefore, the further distant from these, the better.
Q. Why is a mattrass bed, or hearth-rug a good security against injury from lightning?
A. Because they are all non-conductors; and, as lightning always takes in its course the best conductors, it would not select such things as these.
Q. Is it better to be wet or dry during a storm?
A. To be wet: if a person be in the open field, the best thing he can do, is to stand about 20 feet from some tree, and get completely drenched to the skin.
Q. Why is it better to be wet than dry?
A. Because the wet clothes would form a far better conductor than the fluids of our body; and, lightning would roll down the wet clothes, without touching our body at all.
Q. What is the safest thing a person can do to avoid injury from lightning?
A. He should draw his bedstead into the middle of his room, commit himself to the care of God, and go to bed; remembering that our Lord has said, “The very hairs of your head are all numbered.”
Q. What is a lightning-conductor?
A. A metal rod fixed in the earth, running up the whole height of a building, and rising in a point above it.
Q. What metal is the best for this purpose?
A. Stout copper wire.
Q. Why is copper wire better than iron?
A. 1st—Because copper is a better conductor than iron:
2ndly—It is not so easily fused or melted: and
3rdly—It is not so much injured by weather.
Q. What is the good of a lightning-conductor?
A. Metal wire is a most excellent conductor; and as the lightning makes choice of the best conductors, it would run down the metal wire, rather than the bricks of the building.
Q. How far will the beneficial influence of a lightning-conductor extend?
A. It will protect a circumference all round, the diameter of which is (at least) 4 times as long as that part of the rod, which rises above the building.
Q. Give me an example.
A. If the rod rise 2 feet above the house, it will protect the building for (at least) 8 feet all round.
Q. Why are not lightning-conductors more generally used?
A. Because they are often productive of more harm than good.
Q. How can lightning-conductors be productive of harm?
A. If the rod be broken by weather or accident, the electric fluid (being obstructed in its path) will rend the building into fragments.
Q. Is there any other evil to be apprehended from a lightning rod?
A. Yes; if the rod be not big enough to conduct the whole current to the earth, the lightning will fuse the metal, and greatly injure the building.
Q. How stout is it needful for the copper wire to be, that it may conduct the fluid safely to the earth?
A. It should be (at least) one inch in diameter.
Q. Why does lightning sometimes knock down houses and churches?
A. The steeple, or chimney is first struck; the lightning then darts to the iron bars and cramps employed in the building; and (as it darts from bar to bar) shatters to atoms the bricks and stones, which oppose its progress.
Q. Can you tell me how St. Bride’s Church (London) was nearly destroyed by lightning, about 100 years ago?
A. The lightning first struck the metal vane, and ran down the rod; it then darted to the iron cramps, employed to support the building; and (as it flew from bar to bar) smashed the stones of the church, which lay between.
Q. Why did the lightning fly about from place to place, and not pass down in a straight course?
A. Because it always takes in its course the best conductors; and will fly both right and left, in order to reach them.
Q. Why does lightning turn milk sour?
A. Lightning causes the gases of the air (through which it passes) to combine, and thus produces a poison, called nitric acid; some small portion of which, mixing with the milk, turns it sour.[2]
(N. B. Sometimes, the mere heat of the air, during the storm, turns milk sour.)
[2] The air is composed of two gases, called oxygen and hydrogen, mixed together, but not combined. If oxygen is combined with nitrogen, it produces five deadly poisons, viz.—nitrous oxide, nitric oxide, hyponitrous acid, nitrous acid, and nitric acid, according to the proportion of each gas in the combination.
Q. What is the difference between combining and mixing?
A. When different ingredients mingle without undergoing any chemical change, they are said to be mixed; but when the natural properties of each are altered by the union, then those ingredients are said to be combined.
Q. Give me an example.
A. If different coloured sands be shaken together in a bottle, the various grains will mix together, but not combine: but if water be poured on quick lime, the water will combine with the lime, and not mix with it.
Q. Why are the different grains of sand said to be mixed, when they are shaken together?
A. Because they are mingled together, but the property of each grain remains the same as it was before.
Q. Why is water poured on lime, said to combine with it?
A. Because the properties, both of the water and the lime, are altered
