975. _Why is a Barometer called also a "Weather Gla.s.s"?_

Because changes in the weather are generally preceded by alterations in the atmospheric pressure. But we cannot perceive those changes as they gradually occur; the alteration in the height of the column of mercury, therefore, enables us to know that atmospheric changes are taking place, and by observation we are enabled to determine certain rules by which the state of the weather may be foretold with considerable probability.

976. _Why docs the Hand of the Weather Dial change its Position when the Column of Mercury rises or falls?_

Because a weight which floats upon the open surface of the mercury is attached to a string, having a nearly equal weight at the other extremity; the string is laid over a revolving pivot, to which the hand is fixed, and the friction of the string turns the hand as the mercury rises or falls.

977. _Why does Tapping the Face of the Barometer sometimes cause the Hand to Move?_

Because the weight on the surface of the mercury frequently leans against the side of the tube, and does not move freely. And, also, the mercury clings to the sides of the tube by capillary attraction; therefore, tapping on the face of the barometer sets the weight free, and overcomes the attraction which impedes the rise or fall of the mercury.

978. _Why does the Fall of the Barometer denote the Approach of Rain?_

Because it shows that as the air cannot support the full weight of the column of mercury, the atmosphere must be thin with watery vapours.

979. _Why does the Rise of the Barometer denote the Approach of Fine Weather?_

Because the external air, becoming dense, and free from highly elastic vapours, presses with increased force upon the mercury upon which the weight floats; that weight, therefore, sinks in the short tube as the mercury rises in the long one, and in sinking, turns the hand to Change, Fair, &e.

980. _When does the Barometer stand highest?_

When there is a duration of frost, or when north-easterly winds prevail.

981. _Why does the Barometer stand highest at these Times?_

Because the atmosphere is exceedingly dry and dense, and fully balances the weight of the column of mercury.

982. _When does the Barometer stand lowest?_

When a thaw follows a long frost, or when south-west winds prevail.

983. _Why does the Barometer stand lowest at these Times?_

Because much moisture exists in the air, by which it is rendered less dense and heavy. [1]

[Footnote 1: From "The Reason Why--General Science, containing 1,400 Reasons for things generally believed but imperfectly understood."

London: Houlston and Sons.]

984. Cheap Fuel

One bushel of small coal or sawdust, or both mixed together, two bushels of sand, one bushel and a half of clay. Let these be mixed together with common water, like ordinary mortar; the more they are stirred and mixed together the better; then make them into b.a.l.l.s, or, with a small mould, in the shape of bricks, pile them in a dry place, and use when hard and sufficiently dry. A fire cannot be lighted with them, but when the fire is lighted, put two or three on behind with some coals in front, and the fire will be found to last longer than if made up in the ordinary way.

985. Economy of Fuel.

There is no part of domestic economy which everybody professes to understand better than the management of a fire, and yet there is no branch in the household arrangement where there is a greater proportional and unnecessary waste than arises from ignorance and mismanagement in this article.

986. The Use of the Poker.

The use of the poker should be confined to two particular points--the opening of a dying fire, so as to admit the free pa.s.sage of the air into it, and sometimes, but not always, through it; or else, drawing together the remains of a half-burned fire, so as to concentrate the heat, whilst the parts still ignited are opened to the atmosphere.

987. The Use of Bellows (1).

When using a pair of bellows to a fire only partially ignited, or partially extinguished, blow, at first, not into the part that is still alight, but into the dead coals close to it, so that the air may partly extend to the burning coal.

988. The Use of Bellows (2).

After a few blasts blow into the burning fuel, directing the stream partly towards the dead coal, when it will be found that the ignition will extend much more rapidly than under the common method of blowing furiously into the flame at random.

989. Ordering Coals.

If the consumer, instead of ordering a large supply of coals at once, will at first content himself with a sample, he may with very little trouble ascertain who will deal fairly with him; and, if he wisely pays ready money, he will be independent of his coal merchant; a situation which few families, even in genteel life, can boast of.

990. The Truest Economy (1).

To deal for ready money only in all the departments of domestic arrangement, is the truest economy. This truth cannot be repeated too often.

991. The Truest Economy (2).

Ready money will always command the best and cheapest of every article of consumption, if expended with judgment; and the dealer, who intends to act fairly, will always prefer it.

992. Cash vs. Credit (1).

Trust not him who seems more anxious to give credit than to receive cash.

993. Cash vs. Credit (2).

The former hopes to secure custom by having a hold upon you in his books, and continues always to make up for his advance, either by an advanced price, or an inferior article, whilst the latter knows that your custom can only be secured by fair dealing.