A. Yes; in very many ways. For example--a bottle of water wrapped in _cotton_, and frequently _wetted with ether_, will soon freeze. Q. _Why would WATER FREEZE if the bottle were kept constantly wetted with ETHER?_ A. Because _evaporation_ would carry off the heat of the water, and reduce it to _freezing point_. Q. _Why does ETHER freeze under the RECEIVER of an AIR-pump, when the air is exhausted?_ A. Because _evaporation_ is very greatly increased by the _diminution of atmospheric pressure_; and the ether freezes by evaporation. FREEZING MIXTURES. 1. If nitre be dissolved in water, the heat of the liquid will be reduced 16 degrees. 2. If 5 oz. of nitre, and 5 of sal-ammoniac (both finely powdered) be dissolved in 19 oz. of water, the heat of the liquid will be reduced 40 degrees. 3. If 3 lbs. of snow be added to 1 lb. of salt, the mixture will fall to 0° (or 32 degrees below freezing point). The two following are the coldest mixtures yet known:-- 1. Mix 3 lbs. of muriate of lime with 1 lb. of snow. 2. Mix 5 lbs. of diluted sulphuric acid with 4 lbs. of snow. Q. _Why is it more easy to SWIM in the SEA than in a RIVER?_ A. Because the _specific gravity_ of salt water is _greater than that of fresh_, and therefore it _buoys_ up the swimmer better. Q. _How do cooks ascertain if their BRINE be SALT ENOUGH for pickling?_ A. They put an _egg into their brine_. If the egg _sinks_ the brine is _not strong enough_, if the egg _floats_ it _is_. Q. _Why will the EGG SINK if the brine be NOT STRONG enough for pickling?_ A. As an egg is _heavier than water_, it will _sink_ if immersed therein; but if as much _salt_ be added as the water can dissolve, the egg will _float_. Q. _Why will the EGG FLOAT in strong BRINE?_ A. Because the specific gravity of _salt and water_ is greater than that of water _only_. Q. _Why do persons SINK in water when they are UNSKILFUL SWIMMERS?_ A. 1st--Because (in their floundering about) they _take in water_ at their nose and mouth, which makes them _heavier_: 2ndly--FEAR _contracts the body_; and as the body is compressed by fear into a smaller compass, it becomes _heavier_: and 3rdly--The water and fear _take away the breath_; and when the breath is taken from the body, its _bulk is reduced_, and it becomes _heavier_. Q. _Why can QUADRUPEDS swim MORE EASILY than MAN?_ A. 1st--Because the _trunk_ of a quadruped is _lighter than water_, and this is the greatest part of them: 2ndly--The _position_ of a beast in water is a _natural_ one. Q. _Why is it MORE DIFFICULT for a MAN to swim than for a BEAST?_ A. Because the _head and limbs_ of a man (like those of a beast) are _heavier_ than water, and these compose more than _half his body_: 2ndly--The _position_ of a man in water is _unnatural_ to him. Q. _Why can FAT men SWIM more EASILY than SPARE men?_ A. _Fat is lighter than water_; and the _fatter_ a man is, the more _buoyant_ will he be.