276 



SCIENCE. 



tion entertained in those days, the remark of the editor 

 who published these papers is significant, for he says he 

 " regards the whole scheme as a bubble." 



The next paper before me " On the Application of the 

 Gas from Coal to Economical Purposes," by Mr. William 

 Murdock — Phil. Trans., 1808, shows the question to 

 have advanced to the stage when a large building had 

 been illumiuated by gas ; this building was the cotton 

 manufactory of Phillips and Lee, of Manchester, Eng- 

 land, the whole of which, together with the dwelling 

 house ot Mr. Lee, was lighted with gas. 



This was thought, at the time, to be a great feat, and 

 shows by what slow degrees the process of gas illumina- 

 tion was developed ; the idea of a central manufactory 

 of gas, and that of carrying it by pipes throughout a 

 district, never entered the minds of the most advanced 

 advocates of the system, but that each house or estab- 

 lishment should manufacture its own gas and use it, was 

 considered the perfection of gas lighting. 



Mr. Lee distilled the coal in large iron retorts, and the 

 gas was conveyed into large gasometers, where it was 

 washed and purified, and then conveyed to the burners. 

 There were 271 burners on the principle of the Axgand 

 lamp, each of which gave a light, as measured by means 

 of shadows, equal to four mould-candles ol six to the 

 pound ; and 633 burners, called cockspurs, having three 

 apertures only of i~30th of an inch, and of which the 

 light was equal to two and a quarter of the same candles ; 

 so that the whole of the lights were equal to 2,500 

 candles of that size, each of which consumed 4-ioths of 

 an ounce, or 175 grains of tallow in an hour. Mr. 

 Murdoch continues, " the quantity of gas required by 

 this number of burners was 1250 cubic teet in an hour. 

 In some mills where the work is light, the average time 

 required will be three hours, but in this manufactory the 

 yearly averages is two hours a day, or 2,500 cubic feet 

 of gas. This quantity of gas required the distillation 

 of 7 cwt. of cannel coal." The expense of the lights 

 used in this manufactory may theretore be stated thus : 



Cost of no tons ot best Wigan cannel, at 



22s. 6d. is £i 2 3 



Cost of 40 tons of common coals to heat the 



retort at 10s. is 20 



j£*43 



Interest on capital, and wear and tear of ap- 

 paratus 550 



Attendance, the same as when candles are used, 



therefore need not be stated o 



i,6 93 



Deduct value of 70 tons of coke ^93 



Value of 1250 ale gallons of tar not yet sold o ^93 



£600 

 " The expense of candles to give the same light would 

 be, at is. per lb., nearly £ 2,000. The light is peculiarly 

 soft and clear, and ot almost unvarying intensity, so as 

 to be very pleasant to the workmen. It is also free from 

 the danger of spark." 



This will give an idea of the method of making com- 

 parative calculations then used to determine the merits 

 of gas as against the use ot candlts. The editorial re- 

 marks on this paper, might, if the word gas be substi- 

 tuted tor electricity, be taken for one of the criticisms so 

 lately in fashion, and now a little obsolete. 



"The present paper furnishes the necessary data for 

 calculating the quantit) ol coals that would be required 

 to yield a light equal to that ot a given number of candles ; 

 and it affords an easy means of investigating the economi- 

 cal advantages of this process, which seems well adapti dto 

 the illumination of public buildings, large manufactories, 

 and generally speaking, all establishments where a great 

 number of lights arc required ; but we tear the expense 



of the apparatus will always be against its introduction 

 in domestic establishments on a small, or even middling 

 scale." 



The last paper I notice is " On the Advantage of Em- 

 ploying Coal-gas for Lighting Small Manufactories, and 

 for Other Purposes," by Mr. B. Cook, Philosophical 

 Journal, No. 94. 



Mr. Cook in this paper drew attention to the increased 

 price of tallow, on account of the " rupture with Russia," 

 so that the advantage of using coal-gas becomes evi- 

 dent. It is true, he says, that coal itself might increase 

 in value, but, as he suggests, it might lead to an increased 

 search and greater production. 



Mr. Murdock explains the method of making gas for 

 large manufactories, and Mr. Cook in his paper describes 

 his plan for making gas for dwelling houses. " Such an 

 apparatus," he says, " should be an 8 gallon iron pot, with 

 a cover of the same metal luted on with sand. About 

 20 to 25 pounds of coal are put into the pot, and dis- 

 tilled, which requires the combustion of about 25 pounds 

 more of coals. The quantity of gas varies with the 

 quality of the coals, it is passed through water into the 

 reservoir, which only holds about 400 gallons, but in 

 general more is produced ; so that the overplus, perhaps 

 200 gallons, is wasted. From the reservoir the gas is 

 conveyed round the house by means of old gun barrels, 

 used as tubes, and coated once a year, or seldomer, with 

 the produced tar. 



" The gas flame is found superior to that of a lamp for 

 soldering with the blow-pipe. The moment the stop- 

 cock is turned on, the frame is ready for use, while whh 

 oil or cotton wick, the workmen are forced to wait 

 until the lamp is sufficiently on fire." 



The expense of this apparatus was £ 50, but he 

 thought others could be put up for ^40. 



In regard to the light produced, Mr. Cook offers the 

 following facts : " The lights employed in the manufac- 

 tory are 18 or 20, equal to eighteen shillings a week for 

 candles, for 20 weeks, which amounts to £18. It used 

 to cost ^30 a year for oil and cotton for the soldering 

 lamps ; and the coke is certainly worth £2, \os. a year, so 

 that, setting the tar against any little accident that may 

 happen, the whole produce may be taken at ^50. 10s. a 

 year. ' 



Supposing 50 lbs. of coal are used daily, the weekly expen- 

 diture on that head will be 2 shillings, and allowing part 

 of a man's time to attend to making the gas to be worth 

 5 shillings, the whole will be 7 shillings per week or_£ 18, 

 4 shillings a year ; this however is one fourth more than it 

 ought to be, because for 25 to 30 weeks the gas will not 

 be required for lights. And adding to this expense £2 

 a year tor interest on the cost of the apparatus, there 

 will remain a saving of ^30. 6s. in the year. 



For a family using only six candles and one lamp, a 

 gas apparatus would cost from £ 10 to £12, the cost ot 

 which will be saved during the first year. 



The critical remark of the editor of this paper is truly- 

 amusing, for, by a train of reasonining, he states that he 

 is compelled to oppose the introduction ot gas, because 

 it Will raise the price of butchers' meat. The editor 

 argues that if gas supersedes candles, the price of tallow 

 will fall ; therefore, as the tat of animals will be reduced 

 in value, butchers will have to charge a higher price for 

 the leaner portion of the meat, so as to realize the value 

 of the beasts. " There/ere. as food is of more conse- 

 quence than artificial light, it is rather to be depreci- 

 ated." 



A year later Mr. Cook read a second paper "On the 

 Advantages of Coal Gas Light " {Phil. 'Trans. 98), which 

 shows that the methods of preparing the gas was very 

 imperfect, and an unpleasant oder was given off when it 

 was used. In regard to this, Mr. Cook says, in reference 

 to this objection that the smell occasioned by the gas is in- 

 jurious to health, and that "it rather tends to preserve 



