On the combustion of gas for economic purposes / by Henry Letheby.

  • Letheby, H. (Henry), 1816-1876.
Date:
[1866]
Catalogue details

Licence: Public Domain Mark

Credit: On the combustion of gas for economic purposes / by Henry Letheby. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    cubic foot at common temperatures and pressures. Hydrogen, you per- ceive, is the most powerful thermotic agent, and carbonic oxide is the weakest; a pound of the first of these gases will raise 62,030lbs. of water 1°, whereas a pound of the latter will only heat about 4325 lbs. of water to that extent. Examined by the cubic foot, and considering that for every pound of water raised 1°, about 48 cubic feet of air are raised to the same extent, we may say the chief constituents of coal gas have this thermotic power:— Pounds of Water and Cubic Feet of Air raised 1° Fahr. by a Cubic Foot of the Gas Burning in Air. _ .. „ . t Lbs. Water Cub. Ft. Air Cubic *oot ol raised P Fahr. raised 1° Fahr. Hydrogen . Marsh gas . Olefiant gas Propylene . Butylene . Acetylene . Benzole vapour heats 329 . . 15,837 „ 996 . . 47,946 „ 1585 . . 76,299 „ 2376 . . 114,378 3168 . . 152,502 „ 1251 . . 60,220 3860 . . 185,814 Carbonic oxide gas „ 320 . . 15,403 Common coal gas . „ 650 . . 31,290 Cannel coal gas . „ 760 . . 36,585 From this we can determine the practical thermotic power of any of these agents. A cubic foot of common gas will heat 65 gallons of water 1°, or 6 • 5 gallons 10°, or 3 ■ 25 gallons 20°; so that a bath containing 250 gallons of water would require about 77 cubic feet of common gas, or 66 of cannel, to raise its temperature from 55° to 75°. In practice, however, this is rarely attained, because of the faulty construction of the heating apparatus. I find, indeed, that a bath in my own house, made by Phillips, of Skinner Street, takes nearly twice this proportion of gas to heat it, and being in a closed room the atmosphere is almost poisoned before the bath is ready; and the circulation of the hot water is so imperfect, that the top layer be- comes boiling hot before the bottom of the water is warm. This is a sub- ject which requires attention, for it is open to much improvement. Again, with regard to the boiling power of gas, although in good practice a cubic foot of gas should boil off about 4712 grains of water, or about 22 times its own weight, yet this is not often attained, for in an open vessel we rarely evaporate more than 2866 grains of water, or about 13 times its weight. But the heat of the burning gas is more surely applied to the warming of rooms; for, as you will see by the table, a cubic foot of common gas will heat an apartment containing 3129 cubic feet of air 10°, and the same quantity of cannel gas will heat 3658 cubic feet to the same extent. Other illuminating agents will, however, light for light, heat the atmosphere, and vitiate it to a larger extent. This is seen in the table which 1 brought under your notice at the last lecture. Heating and Vitiating Effects of Different Illuminating Agen Burning so as to give the Light of 12 iSperm Candles. ents, when Lbs. Water Oxygen Carb.Acid Air raised consumed, produced, vitiated, 1° Fahr. Cub. Ft. Cub. Ft. Cub. Ft. Cannel gas . . . 1950 . 3'30 2-01 . 50-2 Common gas . 2786 5-45 . 3-21 . 80-2 Sperm oil . . . 2335 . 4-75 3-33 . 83*3 Benzole . . . . 2326 . 4-46 . 3-54 . 88-5 Paraffin . . . . 3619 . 6-81 . 4-50 . 112-5 Camphine . . 3251 . 6-65 4-77 . 119-2 Sperm candles . . 3517 . 7-57 . 5-77 . 131-7 tfax „ . . 3831 . 8-41 . 5-90 . 149-5 Stearic „ . 3747 . 8-82 626 . 156-2 Tallow „ . 5054 12-00 . 873 . 218-3