HYDRO-CARBONS.
All substances composed essentially of the elements, hydrogen and carbon, would come under this designation. These would include coal, wood, petroleum, the fats, resins, wax and many others, with some of the gases, among which may be named light and heavy carburetted hydrogen, CH₄ and C₂H₄ respectively.
PHOSPHORUS BURNING IN OXYGEN.[8]
In the days of our grandfathers tallow candles were almost universally employed for lighting houses, and wood for warming them. It would not be impossible to find even now, in our own country, homes illuminated (?) by a rag burning in a saucer of fat. Some of us are not too young to remember the bundle of candle-rods—nice, straight sticks used in dipping candles—snugly put away for that purpose, alas! sometimes summoned forth to assist in enforcing family discipline!
GREEN FIRE COLORED BY A SALT OF BARIUM.[9]
Strands of twisted cotton wick were suspended from these sticks, and successively dipped into a kettle of hot tallow, until external additions made them of the requisite size. Tin candle moulds finally superseded these. Then the wick was suspended in the center and the fat poured in. In cooling, the candles contracted, and so slipped easily from the moulds. Wax candles can not be cast in moulds, as they expand in cooling. They are made by pouring successive additions upon them. They are afterward given symmetrical form by rolling and shaping. Along the sea coast I have seen women and children gathering bay berries,[10] a fruit about as large as a grain of black pepper and covered with a grayish-white, fragrant wax. When these seeds are placed in hot water the wax dissolves and serves the same purpose as tallow, making delightfully aromatic candles.
Many of the hydro-carbons possess an agreeable odor. Sometimes the woodmen gather the bark and chips of the hickory to smoke hams and shoulders on account of the peculiarly pleasant flavor they impart. In burning, a candle or lamp becomes a gas factory, manufacturing and consuming its own product. The flame consists of three cones. The first, that next to the wick, is composed solely of gas. It is not hot, as can be shown by thrusting the end of a match into it, the match will not ignite. If the match be placed across the flame at the same point it will burn at the edges, but not in the center. A more striking illustration of the fact that the flame is hot only where it comes in contact with the air, can be shown in the following manner: Place on the bottom of an inverted plate some alcohol, in the center set a tiny saucer containing powder; ignite the alcohol, and the powder will remain undisturbed in the center of the surrounding flame until a draft brings the edge of the flame against the powder, when it will at once explode.
Look steadily at the flame of an ordinary candle and you can readily discern the three cones; the first is gas, the second gas in rapid combination with the oxygen of the air, the third the products of this combination—watery vapor, carbonic anhydride, and, possibly, some unconsumed carbon.
RED FIRE COLORED BY A SALT OF STRONTIUM.[11]
The process that goes on in our stoves is essentially the same. The carbon and hydrogen of the wood or coal unite with the oxygen that passes through the draft. Now note a wonderful provision for our comfort. It has already been remarked that the product of combustion consists of the thing burned, plus oxygen. Suppose, in the case of our fires, this product were a solid, we should then be forced to take out of the stove more material than we put in. The Creator has, however, provided that these resulting materials shall take the form of gas or vapor, so that they can float away. The ashes that remain form but a small part of the whole. The two most common products of combustion are watery vapor and carbonic anhydride.
The illumination of our towns and cities has long been accomplished by the use of gas manufactured from coal. Bituminous coal is used for this purpose, and the process consists in heating it to destructive distillation, and afterward condensing and absorbing such portions of the volatilized materials as might clog the gas pipes or interfere with perfect combustion.
Nature, it is now known, has her own gas works, on an immense scale. Thirty-five years ago the village of Fredonia, N. Y., was partially lighted with gas, and the supply is still unexhausted. Indeed, of late, many private individuals have sunk pipes two or three hundred feet, and thus supplied their homes with gas for illuminating, heating, and cooking purposes. In Butler and McKean counties, Pennsylvania, the production of these gas wells is enormous. Many have been burning day and night for years, while others have been utilized for heating and lighting towns and cities. Gas is now extensively used in rolling mills for smelting iron. Petroleum, or rock oil, which is usually associated with this natural gas, has now become of immense value to this and other lands. It is one of the chief articles of export from this country, ranking perhaps as fourth. Wells have recently been struck in Pennsylvania that flowed 5,000 and 6,000 barrels per day.
SODIUM BURNING ON HOT WATER.[12]
There is reason to believe that this material is the product of distillation of organic matter in the earth. It is found in porous rock, usually coarse sand, at depths varying from three hundred to two thousand feet. When the rock above the sand containing oil is tight, the gas is often retained, which by its expansion presses upon the oil and forces it to the surface through the pipes put down for this purpose. This produces a flowing well. When the gas has escaped a pump is necessary.
The most useful hydro-carbon now employed is coal. Its use was first introduced in the latter part of the twelfth century, and as late as the thirteenth century petitions were made by residents of London demanding its exclusion, on account of its injurious effect on the health. But now, Great Britain mines annually more than one hundred million tons of coal. Its uses are manifold. By it England has multiplied her power a thousand fold. It is almost always employed in generating steam, and the aggregate steam power of England is equal to the productive laboring force of four hundred millions of men, or “twice the power of the adult working population of the globe.” Most countries know its value.
POURING CARBON DI-OXIDE FROM ONE VESSEL INTO ANOTHER TO EXTINGUISH FLAME.[13]
Coal is the key that unlocks for us the treasures of the iron ore. It seizes upon the oxygen in the ore, and liberates the pure metal. By a wonderful provision they often exist in the same mountain, side by side. I have seen in Pennsylvania, running out of the same tunnel in the hills, car loads of coal and iron ore.
Among the many advantages possessed by our own country is our immense store of this precious hydro-carbon. With an area of 300,000,000 miles of territory, we have more than 200,000 square miles of known coal producing area, or one in fifteen.
Great Britain has one-half of the coal fields of all Europe, but even she has but one square mile of coal to twenty square miles of territory. Beside, our coal seams are of great thickness, and lie comparatively near the surface. In the far West, vast fields of lignite[14] have been discovered, so that there seems no prospect of our exhausting our fuel supply for ages to come.
The diamond is crystallized carbon, and can be burned, though one would hardly care to be warmed by so costly a fire.
Cleopatra, in a freak of extravagance, dissolved a wonderful pearl, but who could think of the wise queen of England using in so wasteful a manner her Kohinoor.[15] Six of the great diamonds of the world are called, by way of eminence, “The Paragons,” and a romantic interest has been attached to this form of carbon among all nations. In point of fact, however, the black diamonds of the coal pit are more interesting, and of far greater value to mankind than these glittering gems from Golconda,[16] Brazil and the Dark Continent.[17]
TEMPERANCE TEACHINGS OF SCIENCE;
OR, THE POISON PROBLEM.
BY FELIX L. OSWALD, M.D.