A. As soon as the vent peg is taken out, air rushes _through the vent hole_ at the _top of the tub_,--presses the liquor _down_, and _forces it through the tap_. Q. _Why does liquor flow reluctantly out of a BOTTLE held upside down?_ A. Because the _upward pressure of the air_ prevents the liquor from flowing out. Q. _Why should a bottle be held OBLIQUELY, in order to be emptied of its liquor?_ A. Because _air_ will then _flow into the bottle_, and help the liquor out by _balancing the upward pressure_. Q. _Why does wine (poured from a bottle QUICKLY) SPIRT about without going into the decanter?_ A. The liquor fills the _top of the decanter_ (like a _cork_), and leaves _no room_ for the air inside _to escape_; therefore, the decanter (being _full of air_) refuses to admit the _wine_. Q. _Why is BEER made STALE, by being exposed to the AIR?_ A. Because air _absorbs its carbonic acid_, which gave it "life." Q. _Why is PORTER made STALE, by being exposed to the AIR?_ A. Because air _absorbs its carbonic acid_, which gave it "life." Q. _Why does the EFFERVESCENCE of soda water and ginger beer so soon go off?_ A. Because air _absorbs the carbonic acid_, which produced the effervescence. Q. _Why is BOILED WATER FLAT and insipid?_ A. Because the whole of the _carbonic acid is expelled_ by boiling, and _absorbed by the air_. Q. _Why does WATER become FLAT and insipid, after it has been DRAWN some time?_ A. Because air _absorbs its carbonic acid_; and when its carbonic acid is absorbed, the water is flat and insipid. Q. _Why should spring WATER (used for WASHING) be exposed to the AIR?_ A. Spring water _contains carbonic acid_; but (by being exposed to the _air_) this carbonic acid is _absorbed_, and the water becomes _more soft_. Q. _Why does YEAST make BREAD LIGHT?_ A. Flour contains a small portion of _saccharine matter_ (or sugar); and the yeast (mixing with this) produces _fermentation_, as it does in brewing. Q. _How does FERMENTATION make the DOUGH RISE?_ A. During fermentation, _carbonic acid gas is evolved_; but the sticky texture of the dough will not allow it to _escape_, so it _forces up little bladders_ all over the dough. Q. _Why is DOUGH placed BEFORE the FIRE?_ A. 1st--Because the heat of the fire _increases the fermentation_: and 2ndly--It _expands the gas_ which is confined in the little bladders; in consequence of which, the bladders are _blown up larger_, and the dough becomes lighter and more porous. Q. _Why is BREAD HEAVY, if the dough be removed from the fire?_ A. Because the dough _gets cold_, and then the air in the bladders _condenses_,--the paste falls,--and the bread is close and heavy. Q. _Whence does the HEAT of FIRE arise?_ A. The _carbon of fuel_ (when heated) _combines with the oxygen of the air_, and produces _carbonic acid gas_: again, the _hydrogen of the fuel_ combining with _other portions of oxygen_, condenses into _water_; by which chemical actions _heat is evolved_.