CHAPTER XIX.. Carbonic Acid Gas.

CARBONIC ACID GAS.

Q. What is CHOKE DAMP?

A. Carbonic acid gas accumulated at the bottom of wells and pits, which renders them noxious, and often fatal.

Q. Why is not this carbonic acid TAKEN UP by the AIR, and DIFFUSED, as it is in cities?

A. Because (being heavier than common air) it cannot rise from the well or pit; and no wind can get to it to blow it away.

Q. Is CARBONIC ACID WHOLESOME?

A. No; it is fatal to animal life, when inhaled through the mouth; acting on the stomach, as a narcotic poison (i. e. a poison which produces death from drowsiness).

Q. How can any one KNOW, if a place be infested with CARBONIC ACID GAS?

A. If a pit or well contain carbonic acid, a candle (let down into it) will be instantly extinguished. The rule, therefore, is this--Where a candle will burn, a man can live; but what will extinguish a candle, will also destroy life.

Q. Why does a MINER lower a CANDLE into a mine, before he descends?

A. Because the candle will be extinguished, if the mine contains carbonic acid gas: but if the candle is not extinguished, the mine is safe, and the man may fearlessly descend.

Q. Why are PERSONS sometimes KILLED, by leaning over BEER VATS?

A. Vats (where beer has been made) contain a large quantity of carbonic acid gas, produced by the "vinous fermentation" of the beer; and when a man incautiously leans over a beer vat, and inhales the carbonic acid, he is immediately killed thereby.

Q. Why are PERSONS often KILLED, who enter BEER VATS to clean them?

A. Carbonic acid (being heavier than atmospheric air) often rests upon the bottom of a vat: when, therefore, a person enters the vat, and stoops to clean the bottom, he inhales the pernicious gas, which kills him.

Q. Why are the JUNGLES of Jarva and Hindostan so FATAL to life?

A. Because vast quantities of carbonic acid are thrown off by decaying vegetables; and (as the wind cannot penetrate the thick brushwood to blow it away) it settles there, and destroys animal life.

Q. Why are PERSONS sometimes KILLED by having a CHARCOAL FIRE in their bed-rooms?

A. When charcoal is burned, the carbon of the charcoal unites with the oxygen of the air, and forms carbonic acid gas, which is a narcotic poison.

Q. Why does the carbonic acid gas of a CHARCOAL FIRE RISE and DISPERSE itself about the room; whereas the carbonic acid gas of a BEER VAT SETTLES near the FLOOR?

A. The carbonic acid gas of a charcoal fire is heated by the combustion of the fuel, and rises; but the carbonic acid gas of a beer vat is not heated, and, therefore, rests on the bottom of the vat.

Q. Why do persons throw LIME into BINS to PREVENT their offensive SMELL, in summer time?

A. Bins contain large quantities of carbonic acid gas, which readily combines with lime, and produces "carbonate of lime," which is entirely free from all offensive odour.

Q. Why do persons throw LIME into SEWERS in summer time?

A. Sewers (like bins) contain large quantities of carbonic acid, which readily combines with lime, and produces carbonate of lime; and thus the offensive gas of the sewer is neutralized.

Q. Can carbonic acid be removed in any way BESIDES by LIME?

A. Yes; water thrown into a pit will disperse the carbonic acid.

Q. What effect has WATER on CARBONIC ACID GAS?

A. Water (under pressure) absorbs carbonic acid gas; and parts with it (when the pressure is removed) in the form of EFFERVESCENCE.

Q. Why does AERATED WATER effervesce, when the CORK is removed?

A. While the cork was fastened down, the water absorbed the carbonic acid; but the moment the pressure is removed (by taking out the cork) the gas is given out with effervescence.

Q. Why does SODA WATER effervesce?

A. Soda water contains 8 times its own bulk of carbonic acid gas, which makes its escape in effervescence, the moment that the cork is removed.

Q. Why does GINGER POP fly about in froth, when the string of the cork is cut?

A. All vinous fermentation produces carbonic acid gas. While the cork is fast, the water of the liquor absorbs the carbonic acid; but the moment that the pressure is removed, the gas is given off in effervescence.

Q. Why does BOTTLED ALE froth, more than DRAUGHT ale?

A. Because the pressure is greater in a bottle than in a tub which is perpetually tapped: and effervescence is always produced in proportion to the pressure.

Q. Why does bottled ALE and PORTER become "LIVELY" and FROTHY by being SET before the FIRE?

A. The heat of the fire expands the air (between the liquid and the cork), and as this air expands, it presses the liquid down, which causes effervescence.

Q. What produces the FROTH of BOTTLED PORTER?

A. The carbonic acid gas, produced by its vinous fermentation; which is absorbed by the liquor so long as the bottle is well corked, but is given off in froth as soon as the pressure of the cork is removed.

Q. What gives the pleasant ACID taste to soda water, ginger beer, champagne, and cider?

A. The presence of carbonic acid, generated by fermentation, and liberated by effervescence when the pressure of the cork is removed.

Q. Why does fresh SPRING WATER SPARKLE, when poured from one vessel to another?

A. Because fresh spring and pump water contain carbonic acid; and it is the presence of this gas which makes the water sparkle.

Q. What is the FERMENTATION of BEER and WINE?

A. The production of carbonic acid gas and al'cohol.

Q. How is CARBONIC ACID GAS produced by FERMENTATION?

A. Malt and fruit both contain sugar; and sugar consists of carbon, oxygen, and hydrogen. In fermentation, a part of the carbon and oxygen of the sugar escape, in the form of carbonic acid gas.

Carbonic acid gas is a compound of carbon and oxygen, in the following proportions:--3 lbs. of carbon and 8 lbs. of oxygen will form 11 lbs. of carbonic acid gas. Now, 100 lbs. of white sugar contains 43 lbs. of carbon; 50 lbs. of oxygen; and 7 lbs. of hydrogen.

Q. How is AL'COHOL produced by FERMENTATION?

A. The hydrogen of the sugar combines with the residue of the oxygen and carbon to form "AL'COHOL."

Q. What is AL'COHOL?

A. Al'cohol is the spirit of wine or beer, obtained by fermentation.

(100 gallons of alcohol consist of 38 gallons of oxygen; 43-1/2 of carbon; 15 of hydrogen; and 3-1/2 of nitrogen.)

Q. Why is BARLEY MALTED?

A. Because germination is produced by the artificial heat; and in germination the starch of the grain is converted into sugar.

Q. How is barley malted?

A. The barley is moistened with water, and heaped up; by which means, great heat is produced, which makes the barley sprout.

Q. Why is not the BARLEY suffered to GROW, as well as SPROUT?

A. Plants in the germ contain more sugar than in any other state; as soon as the germ puts forth shoots, the sugar of the plant is consumed, to support the shoot.

Q. How is BARLEY PREVENTED from SHOOTING, in the process of MALTING?

A. The barley is put into a kiln as soon as it sprouts; and the heat of the kiln checks or destroys the young shoot.

Q. Why is YEAST put into BEER to make it WORK?

A. Yeast supplies the beer with nitrogen, which is one of the ingredients of alcohol.

Alcohol consists of oxygen, carbon, and hydrogen, (obtained from the sugar of malt), and nitrogen, (obtained from yeast).

Q. Why is it NOT needful to put YEAST into WINE?

A. Because fruit contains carbon, hydrogen, oxygen, and nitrogen, in the form of "gluten;" and, therefore, ferments spontaneously.

(Gluten is explained fully in the Appendix.--Turn to the word in the Index.)

Q. Does not MALT contain carbon, hydrogen, oxygen, and nitrogen, as well as FRUIT?

A. No; the sugar of malt contains carbon, hydrogen, and oxygen, but no nitrogen; in consequence of which, yeast (which contains nitrogen) is added to the wort.

Q. Why do NOT GRAPES ferment while they hang on the VINE?

A. 1st--Because the skin lets out the water of the pulp, which causes the grapes to shrivel and dry up: and

2ndly--The skin prevents the admission of oxygen into the pulp, from the air without.

Q. What is the FROTH or SCUM of fermented LIQUORS?

A. Carbonic acid gas, which (being heavier than common air) settles on the top of the liquor, in the form of scum.

Q. Why does a small piece of raw MEAT, or a few RAISINS improve FLAT BEER?

A. 1st--Because they supply it with nitrogen to form it into al'cohol.

2ndly--As the raw meat, &c. putrifies, it gives off carbonic acid gas into the beer, which gives it "life."

Q. Why is BEER FLAT, if the cask be open too long?

A. Because too much of the carbonic acid gas (produced by fermentation) is suffered to escape.

Q. How is the CARBONIC ACID GAS of BEER generated?

A. The saccharine (or sugar) of the malt is converted by fermentation into carbonic acid gas and alcohol.

Q. Why does BEER turn FLAT, if the VENT PEG be left OUT of the tub?

A. Because the carbonic acid gas escapes through the vent hole.

Q. Why will NOT beer RUN OUT of the tub, till the VENT PEG is taken out?

A. When the tap is turned, air rushes through the tap into the bottom of the tub, and holds the liquor in.

The upward pressure of air is illustrated by the

following simple experiment:--Fill a wine-glass with water; cover the top of the glass with a piece of writing paper; turn the glass topsy turvy, and the water will not run out. The paper is used merely to give the air a medium sufficiently dense to act against.

Q. Why does the BEER RUN FREELY, immediately the VENT PEG is taken out?

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.

Q. Whence does the HEAT of our own BODY arise?

A. The carbon of the blood combines with the oxygen of the air inhaled, and produces carbonic acid gas; which produces heat in a way similar to burning fuel.

Q. Whence does the HEAT of a DUNGHILL arise?

A. The straw, &c. of the dunghill undergoes fermentation as it decays: the fermentation produces carbonic acid gas, and heat is evolved by a species of combustion (as in the two former cases).

Q. What changes do VEGETABLES undergo from PUTREFACTION?

A. The hydrogen of the vegetables combines with the oxygen of the air, and forms water: again, the carbon of the vegetables combines with oxygen of the air, and forms carbonic acid gas. Putrefaction, therefore, is only another species of combustion.

Q. What changes do ANIMAL bodies undergo from PUTREFACTION?

A. The same as vegetables, with this addition--they give out ammonia, sulphur, and phosphorus also; which causes the offensive smell of putrefying animal bodies.

Q. Why is LIME heated by a KILN?

A. All marl and chalk abound in carbonic acid; and (when heated by a fire) the carbonic acid flies off in gas, producing great heat.

Q. What is MORTAR?

A. Lime mixed with sand and water.

Q. What is LIME?

A. Lime-stone burnt produces lime.

Q. Why is the lime-stone BURNT, in order to make it into LIME?

A. The fire expels the carbonic acid, and converts the hard lime-stone into a loose powder.

Q. Why does MORTAR become HARD, after a few days?

A. Because the lime re-imbibes the carbonic acid of the air, which was expelled by fire; and the loose powder again becomes as hard as the original lime-stone.

Q. Why is MORTAR adhesive?

A. When the carbonic acid is expelled, the hard lime-stone is converted into a loose powder, which (being mixed with sand and water) becomes a soft and sticky plaster; but, as soon as it is placed between bricks, it imbibes carbonic acid again, and hardens into lime-stone.