A Guide To The Scientific Knowledge Of Things Familiar Part 77

Q. _Of what is SOAP made?_

A. Of kelp (or the ashes of sea-weed dried and burnt in a pit) mixed with oil or fat.

YELLOW SOAP is made of whale-oil, soda, and resin. SOFT SOAP is made of oil and potash. HARD SOAP of oil and soda.

Q. _Why does WATER CLEAN dirty LINEN?_

A. Because the _oxygen_ of the water attaches itself to the _stains of the linen_, and _dissolves_ them; as oxalic acid dissolves ink spots.

Q. _Why does SOAP greatly INCREASE the cleansing power of water?_

A. 1st--Because soap _increases the oxygen_ of the water: and

2ndly--It _neutralizes the grease_ of the things washed.

Q. _Why is RAIN WATER SOFT?_

A. Because it has _not come in contact with earths and minerals_.

Q. _Why is it MORE EASY to WASH with SOFT water than with HARD?_

A. Because it unites freely with the soap, _dissolving_ it instead of _decomposing it_, as hard water does.

Q. _Why do WOOD ASHES make HARD water SOFT?_

A. 1st--Because the _carbonic acid of the wood ashes_ combines with the _sulphate of lime in the hard water_, and converts it into _chalk_: and

2ndly--The _sulphuric acid of the water_ combines with the _potash of the wood ashes_, and prevents it from neutralizing the oily matter of the soap.

Q. _Why has RAIN water such an UNPLEASANT SMELL, when it is collected in a rain water tub or tank?_

A. Because it is impregnated with _decomposed organic matter_, washed from roofs, trees, or the casks in which it is collected.

Q. _Why does WATER MELT SUGAR?_

A. Because very minute particles of water _insinuate themselves into the pores_ of the sugar, and force the crystals _apart from each other_.

Q. _Why does WATER MELT SALT?_

A. Because very minute particles of water insinuate themselves into the _pores of the salt_, and force the crystals _apart from each other_.

Q. _Why does melted SUGAR or SALT give a FLAVOUR to the WATER?_

A. Because the sugar or salt (being disunited into very minute pieces) _floats about the water_, and mixes with _every part_.

Q. _Why does HOT water melt sugar and salt QUICKER than COLD water?_

A. 1st--Because the _heat_ of the water entering the pores of the sugar or salt, _opens a pa.s.sage for the water_: and

2ndly--The _particles of hot water_ being _smaller_ than those of cold, can _more readily penetrate_ the pores of salt or sugar.

Q. _Why is SEA-water SALT?_

A. 1st--Because it contains _mines of salt_ at the bottom of its bed:

2ndly--It is impregnated with _bituminous matter_, which is brackish: and

3rdly--It contains many _putrid substances_, which increase its brackishness.

Q. _Why is NOT RAIN-water SALT, although most of it is evaporated from the SEA?_

A. Because _salt will not evaporate_; and, therefore, when sea-water is turned to vapour, its _salt is left behind_.

Q. _Why does STAGNANT water PUTREFY?_

A. Because leaves, plants, insects, &c. are decomposed in it.

Q. _Why is STAGNANT water full of WORMS, EELS, &c.?_

A. Because numberless insects _lay their eggs_ in the leaves and plants which float on the surface; these eggs are soon hatched, and produce swarms of worms, eels, and insects.

Q. _Why are FLOWING waters FREE from these IMPURITIES?_

A. 1st--Because the motion of running water _prevents its fermentation:_

2ndly--It _dissolves the putrid substances_ which happen to fall into it: and

3rdly--It casts _on the bank_ (by its current) such substances as it cannot _dissolve_.

Q. _Why does RUNNING water OSCILLATE and WHIRL in its current?_

A. 1st--Because it _impinges against its banks_, and is perpetually diverted from its forward motion: and