Volume 2

Chemistry, theoretical, practical, and analytical : as applied and relating to the arts and manufactures / by Dr. Sheridan Muspratt.

  • James Sheridan Muspratt
Date:
[1860]
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry, theoretical, practical, and analytical : as applied and relating to the arts and manufactures / by Dr. Sheridan Muspratt. Source: Wellcome Collection.

    201/644 (page 157)
    instances, that these two points give a value which agrees very well with carefully-conducted photometri- cal experiments. By durability, is to be understood the time during which a certain volume of gas will continue to afford a standard amount of light. Bromine is employed by many to replace the chlorine in con- densing the heavy carbo-hydrogens, and is, in many respects, more convenient for manipulation. In both cases, the vapors of these substances left after conden- sation require to be removed from the gaseous mixture by a solution of potassa before the amount of con- densation is estimated. Anhydrous sulphuric acid, obtained by warming the Nordhausen acid, is pre- ferred by others for effecting this condensation, a ball of porous coke attached to a platinum wire being saturated with the acid and thrust up into the mixture of gases. The substances condensed from the gas by all these agents appear to be the same; but from what has been stated with reference to the nature of these condensed hydrocarbons from different specimens of coal-gas, the illuminating power of the gas must de- pend far more upon the chemical constitution, and upon the a'mount of carbon which they respectively contain, than upon the volumes which they occupy before condensation; and hence, although the test may be a good one, obtained from the same species of coal under like conditions, and containing the same kinds of hydrocarbons, it is not applicable as a means of setting a value upon gases obtained under different circumstances from different species of coal. The substances condensed by these re-agents are probably similar, if not identical, in composition with those condensed from oil-gas and resin-gas. It has been ascertained, by comparing the density of ordinary Newcastle coal-gas before and after condensation by bromine, that the vapors of the light-giving portions give a specific gravity ranging from 2-8 to 3-3. The liquid condensed from resin-gas by Mr. Couerbe yielded six fluids, the nature of which, with the calcu- lated and experimental density of their vapors, are given in the following table :— Density of Vapor. A V i No. Calculated. Found. i. c., H*. 1-763 .... 2-000 2. c5 h4, 2-385 .... 2-254 3. c6 h4 2-806 .... 2-802 4. C7 h4 3-230 3-340 5. c8 h4, 3-660 .... 3-765 6. ^22’ 2-665 .... 2-637 The first of these has a specific gravity about equal to the condensable matter in Wigan cannel and Ram- sey’s cannel, while the third and fourth resemble that from Pelaw, Pelton, and other Newcastle coals. A more elastic vapor probably remained in the gas from which these substances were condensed, which would have a lower specific gravity, and come to resemble the condensable matters and Lesmahagow cannel-gas. The specific gravity of the condensable matter from these gases may be seen from the annexed table by Mr. Evans of the Westminster Gas Works, taken from the Journal of Gas-lighting:— Name of Coat Gas per ton. Condensed per cent. . by bromine. Specific gravity of gas. Specific gravity of condensed matter. Fhotogenic Power. Actual. By analysis. Boghead, 15,000 30- •752 1-21 37-75 36-3 Lesmahagow, No. 1, 13,500 16- •642 1-64 27-1 26-24 Do., No. 2 13,200 17- •618 1-43 24-8 24-31 Capeldrae, 14,400 16-5 •577 1-29 19-75 21-28 Amiston, 13,600 17- •626 1-40 22-50 23-80 Ramsey, 10,300 12-5 •548 1-82 21-40 22-95 Wemyss, 14,300 14-5 •580 1 87 24-50 27-11 Kirkness, 12,800 10-2 ■562 1-95 21-20 19-88 Knightswood, 13,200 9-5 •550 2-28 19-00 21-66 Wigan—Ince Hall, 11,400 11-5 •528 1-77 20-00 20-35 The following table shows the illuminating value of the gas obtained from Newcastle coal, and may serve as a fair indication of the character of the gas supplied in the metropolis:— Name of Coal. Gas per ton Illuminat- ing power. Specific gruvity of gas. Condensa- tion per cent Pelton, 11,000 14-0 •430 4-5 Pelton Cannel, 11,500 18-5 •521 10-5 Leverson, 10,800 12-5 •425 4- Leverson Cannel, 11,600 18- •523 10- Washington, 10,000 14- •430 5- Washington Cannel,.. 10,500 18- •500 10-5 Pelaw 11,000 12-75 •420 4-5 Mew Pelton, 10,500 12- •415 4-75 Dean’s Primrose, 10,500 13-5 •430 5- Ponesfield,.. 10,500 11-5 •398 3-75 Gosforth, 10,000 12- •402 4- West Hartley,... 10,500 12-5 •420 4-2 Hastings Hartley,.... 10,300 12-5 •421 4-3 ttlenkinsop,... 9,700 14- •450 6- The only sure method of arriving at the actual amount of carbon in a gaseous mixture, and at the same time showing the character of the carbonaceous compounds contained in it, is to combine the conden- sation method with an organic analysis, or by the old plan of combustion with oxygen, as proposed by Henry, noting the quantity of oxygen consumed, and the amount of carbonic acid produced. Thus, a known volume of coal-gas is mixed with an excess of oxygen and exploded, the amount of carbonic acid produced and of oxygen consumed being ascertained. An- other equal volume is then treated with an absorbent, as anhydrous sulphuric acid, and after all the residue is again mixed with oxygen, and exploded; the amount of carbonic acid being again ascertained, and deducted from the quantity obtained by exploding the original gas. The quantity of carbon contained in the con- densed portion of the gas being thus ascertained, its value as an illuminating agent may be calculated accordingly. There appear to be some compounds of