GAS MAKING STATISTICS. deavoured to induce the directors of the London gas-works to employ a better coal, and generate a more richly carburetted gas, which in much smaller quantity would give as brilliant a light, without heating the apartments unpleasantly, as their highly hydrogenated gas now does. Were his judicious views adopted, coal gas would soon supersede oil, and even wax candles, for illuminating private mansions. For the following valuable statistical details upon gas-light, (says Dr. Ure in his Dictionary of Arts and Manufactures) my readers are indebted to Joseph Hedley, Esq., engineer, of the Alliance Gas Works, Dublin; a gentleman who to a sound knowledge of chemistry, joins such mechanical talent and indefatigable diligence, as qualify him to conduct with success, any great undertaking committed to his care. He has long enCopy of a Paper laid before a Committee of the House of Commons, showing not only the relative values of the Gases produced at the undermentioned places, but showing in like manner the relative economy of Gas as produced at the different places, over Candles. By Joseph Hedley, Esq. Memorandum.-It will not fail to be observed, that in deducing the comparative value between candles and gas by these experiments, the single jet (and in every instance of course it was the same), has been the medium. This, however, though decidedly the most correct way of making the comparative estimate of the illuminating power of the several gases, is highly disadvantageous in the economical comparison, inasmuch as gas burnt in a properly regulated argand burner, with its proper sized glass, air aperture, and sufficient number of holes, gives an advantage in favour of gas * 100 lbs. of candles are estimated to burn 5,700 hours. †The candles cost 31, 2s. 6d. The Liverpool Old Company have since re consumed in an argand, over a jet burner, of from 30 to 40 per cent. At the same time it must not be overlooked that in many situations where great light is not required, it will be found far more economical to adopt the use of single jets, which by means of swing brackets and light elegant shades, becomes splendid substitutes for candles, in banking establishments, offices, libraries, &c. &c. Note.-In Glasgow, Edinburgh, Dundee, Perth, and the Scotch towns generally, the Parrot, or Scotch Cannel coal is used; in illuminating power and specific gravity the sorted to the use of Cannel Coal, and consequently very nearly assimilate to the Liverpool New Company in illuminating power. gas produced is equal to that from the best description of Cannel coal in England. The price per 1000 cubic feet ranges about 98., with from 5 to 30 per cent. off for dis counts, leaving the net price about 98., to be equal in the above table to 100 lbs. of candles. Epitome of Experiments made in Gas produced from different qualities of Coal, and consumed in different kinds of Burners: tried at the Sheffield Gas Light Company's Works, and laid before a Committee of the House of Commons. By Joseph Hedley, Esq. 15.85 candles. Average quantity of gas made from the charge (6 hours) 4.33 cubic feet per lb., or 9,700 cubic feet per ton of 20 cwt. Increase of coke over coal in measure, not quite 30 per cent. Loss in weight between coal, coke, and breize 56 lbs., converted into gas, tar, ammonia, &c. 2nd Experiment, May 28th.-Carlisle coal (Blenkinsopp). 224 lbs. produced 1010 cubic feet of gas, 4 bushels of coke of good quality though small; increase of coke over coal in measure not quite 30 per cent. Loss in weight, same as foregoing experiment. Average quantity of gas made from the charge (6 hours) 4.5 cubic feet per lb., or 10,080 per ton. Total.. 556 or 921 115 •421 5 81 2.03 2.36 921 or 2 feet 9 inches. Average of the above gas, 6-hour charge. Average of the above gas at 4-hour charge. Production of gas in 6 hours 556 feet, or at the rate of 11,120 cubic feet per ton. The relative value of these productions of gas is as follows, viz..-11,120 at 16-10ths per hour nearly (or 1.5916 accurately) and equal to 203 candles, the 11,120 feet would be equal to and last as long as 1597 candles, or 266 lbs. of candles. 9.200 at 121-10ths per hour (or 1-2375 accurately, and equal to 236 candles; the 9,200 feet would be equal to 1949 candles, or 324 lbs. candles. Now 266 lbs. of mould candles, at 78. 6d. per dozen lbs. will cost 81. 68. 44d., whilst 324 lbs, of mould candles, at 78. 6d. per dozen lbs. will cost 107. 3s. Shewing the value of 4-hour charges over 6-hour charges; and of 9,200 cubic feet over 11,120 cubic feet. Illuminating power.-At end of first hour. Distance of candle from Candles. 73 or 2.49 "} 70 or 2.72 { Note.-9,500 cubic feet of Wigan Cannel coal gas are equal in illuminating power to 859 1-6th lbs. of candles, which at 78. 6d. per dozen lbs., will cost 257. 10s. 5d. It is also found that any burner with superior gas, will consume only about half the quantity it would do with common gas. 4th Experiment, May 30th.-Cannel and Cardiff coal mixed and, together 112 lbs., produced 460 feet of gas; 2 bushels of coke of good quality; increase of coke over coal in measure about 30 per cent. ; loss in weight, 41 lbs.; coke weighed 71 lbs., no breize. Average quantity of gas made from the charge, (4 hours) 4.1 cubic feet, per lb., or 9,200 per ton. This gas very indifferent. 70 or 2.72 do. do. do. do. Cubic feet. 12-10ths 11-10ths 11-10ths Specific gravity 3.44; 5 feet per hour, with a 20-hole argand burner, equal to 14.66 candles. 5th Experiment, May 31st.-Carlisle coal, 112 lbs. produced 410 feet of gas; other products, same as in former experiments with this coal, but heat very low. on different qualities of coal, and mixtures of ditto, too tedious to insert here, though extremely valuable, and all tending to show the superior value of gas produced at short over long charges; and also showing the importance and value of coal producing gas of the highest illuminating power; among which the Cannel coal procured in Lancashire, Yorkshire, and some other counties of England and Wales, and the Parrot or splent coal of Scotland, stand pre-eminent. Note. In all the foregoing experiments the same single-jet burner was used; its flame in all instances exactly 4 inches high. The coal when drawn from the retort was slaked with water, and after allowing some short time for drying, was weighed. General Summary. For lighting London and its suburbs with gas, there are 18 public gas works. 12 do. companies. 2,800,000l. capital employed in works, pipes, tanks, gas-holders, apparatus. 450,000. yearly revenue derived. 180,000 tons of coals used in the year for making gas. 1,460,000,000 cubic feet of gas made in the year. 134,300 private burners supplied to about 40,000 consumers. 30,400 public or street do. N.B. about 2650 of these are in the city of London. 380 lamplighters employed. 176 gas holders; several of them double ones, capable of storing 5,500,000 cubic feet. 890 tons of coals used in the retorts on the shortest day, in 24 hours. 7,120,000 cubic feet of gas used in the longest night, say 24th December. About 2500 persons are employed in the metropolis alone, in this branch of manufacture. Between 1822 and 1827 the quantity nearly doubled itself, and that in 5 years. Between 1827 and 1837 it doubled itself again. NOTES AND NOTICES. Paton's Specimens of Penmanship.-These specimens of art are certainly the most beautiful we have ever seen of the kind. The command of hand which they evince in their author is astonishing. We are free to confess that this is one branch of art to which the science of mechanism can lend but little aid; "the mechanism of the hand" is here all triumphant, and exercised under the guidance of a mind possessed of correct ideas of the beautiful; it has enabled Mr. Paton to earn for himself the rank of first penman of the day. Hall's Patent Condensers.-We have been favoured with the perusal of a letter, dated Bombay, 11th September, 1839, from Mr. Clacher, the chief engineer of the East India Company's vessel, Zenobia (late Kilkenny), which has been fitted with Mr. Hall's patent condensers. Mr. C. states that the condensers were used during the whole of the voyage from Greenock to Bombay, that complete condensation was effected, the barometer showing a vacuum of from 28 to 29 inches; that the vessel ran from Cork to St. Helena without blowing out; that upon then blowing out, no incrustation or dirt was found in the boilers; that from St. Helena to Bombay there was no blowing out, and upon the boilers being examined by Capt. H. B. Turner, mint engineer, he was surprised to see them so remarkably clean. The Kilkenny was sent from Bombay with the mail to Muscat, against the south-west monsoons; she niade an excellent passage, and beat the Berenice. The consumption of fuel never exceeded 15 cwt. per hour; the engines are of 300 horse power. We have also seen a letter from Mr. R. Tayler, engineer of H. M. 8. Megara, to which Mr. Hall's condensers have been likewise applied. Mr. Taylor states that the engines of this vessel have been under his care for twelve months, and that Mr. H's principle of condensation "is good in every respect." The boilers had been blown off once since leaving England, in consequence of the joints of the mud hole doors giving way; the water had been seven months in them, and was "as fresh as first put in." "The method made use of to clear the flues (tubes of the condenser?) answers very well, and keeps them as clean as new-by dissolving 20 lbs. of potash in 6 gallons of water, and injecting it boiling into the condensers, once in every twelve days steaming." The Armed Steamer "Nemesis."-There is now lying in the half-tide basin of the Clarence docks, Greenock, a very beautiful iron steamer, constructed by Mr. John Laird, of North Birkenhead, bearing the above name. She is fitted up with one engine of 120 horse power, and armed with two 32 pound carronades, the one fore and the other aft, which move on solid swivel carriages. Her draught of water is under four feet. Her crew will consist of 40 men. She will, it is said, clear out for Brazil, but her ultimate destination is conjectured to be the Eastern and Chinese seas. On Monday last she made an excursion as far as the floating light, for the purpose of trying her machinery, which was found to work admirably.—Edinburgh Observer. Inventor of the Mule.-A daughter of the late Samuel Cromptou, sole inventor of the "mule," is compelled to apply for parochial relief; while the family of Arkwright, who, in the first instance, merely copied the invention, the machine, ranks among the wealthiest in the kingdom.-Lancaster Guardian. Grain-drying Machinery.-The Dukes of Cambridge and Richmond, accompanied by Mr. Andelle, Mr. Marsh, and Mr. Kendall, lately inspected the patent revolving granary, for the preservation and improvement of corn, and were pleased to express themselves highly gratified at the introduction of so useful a machine into this country. It is intended to have it removed to Cambridge for the next great agricultural meeting.-Times. LONDON: Printed and Published for the Proprietor, by W. A. Robertson, at the Mechanics' Magazine Office, No. 166, Fleet-street.-Sold by A. & W. Galignani, Rue Vivienne, Paris. |