Dec. 1 6, 1880] 



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151 



held from time to time in different towns throughout the 

 country, its object being to form a bond of union among 

 those who cultivate mineralogy or who wish to see this 

 science restored to the place which it ought to hold in a 

 land where so much sound geological work is being done. 

 The Society publishes a " Mineralogical Magazine," of 

 which three volumes and part of a fourth have already 

 appeared. This publication contains numerous papers 

 by Dr. Heddle and the indefatigable secretary, Mr. 

 Collins, also some by Mr. Sorby, the late Mr. J. C. 

 Ward, Prof. Bonney, and other well-known writers. No 

 one need fear to encounter in its pages the resuscitated 

 ghosts of the old mineralogical "Dryasdusts." Peace 

 to their manes ! They did good though limited work 

 in their day, which deserves our respect for its thorough- 

 ness. But, with affectionate reverence for these early 

 masters and their crabbed lingo, we breathe a more open 

 breezy atmosphere now. The mineralogist's ken sweeps 

 far beyond the limits of his cabinet and laboratory. 

 Hand-in-hand with the geologist and paleontologist, 

 being elder brother to both, he takes his share in the 

 task of unravelling the structure and history of the earth. 

 Towards the attainment of this union the Mineralogical 

 Society aims, and it deserves the heartiest wishes for its 

 success. Arch. Geikie 



SMOKELESS LONDON 



I WRITE for the purpose of expounding a scheme 

 which, if adopted, would make London a smokeless 

 city. 



When taking upon myself to explain a subject in a few 

 minutes which has taken many years to develop in my 

 own mind, there is a great temptation to put the reader 

 in possession of the steps which led to the conclusion. 

 The conclusion itself however has so much to recommend 

 it that I will confine myself to the results of my reasoning 

 only. It is enough to say that they were arrived at to a 

 great extent by an exhaustive exclusion of less feasible 

 plans. 



First then I propose to take advantage of the existing 

 plant of the gas companies. I find they are amply 

 sufficient for tlie purpose. 



Instead of taking 10,000 cubic feet of gas per ton from 

 the coal, I propose to take 3333 cubic feet, and to pass 

 three times the quantity through the retorts, or any other 

 proportion that may be found most convenient. The 

 result of doing so is startling. 



The companies will have double the quantity of by- 

 products they have at present in the shape of tar and 

 ammoniacal liquids ; the community will have 24-candle 

 gas instead of i6-candle gas ; the fuel resulting from the 

 process will light readily, and it will make a cheerful fire 

 that gives out 20 per cent, more heat than common coal ; 

 London would become a smokeless city. 



In dealing with the figures I shall take them roughly, 

 but in such a way that by including a few outlying cor- 

 porations they could be made absolutely correct. 



I take the total annual consumption of coal in London 

 to be 6,000,000 tons. Of this I take 2,000,000 tons to be 

 the annual consumption of the gas companies. The total 

 quantity of fuel used for general purposes 1 take to be 

 4,000,000 tons of coal and 1,000,000 tons of coke sold by 

 the gas companies. 



We shaU now see what would be the result if we treat 

 the whole of the 6,000,000 tons in the retorts on an ex- 

 traction of less than three hours, instead of the six hours 

 at present prevailing. 



The total quantity of i6-candle gas consumed in London 

 may be taken at 20,000,000,000 cubic feet. This would be 

 at the rate of 3333 cubic feet per ton upon 6,000,000 tons, 

 the total quantity of coal consumed in London. The 

 residual smokeless fuel would amount to 5, 100,000 tons. 

 Of this 1,000,000 tons would be required for the extraction 

 of the gas, leaving 4,ioo,coo available for the general 



uses of the community. This has to be compared with 

 the 4,000,000 tons of coal and the 1,000,000 tons of coke 

 already referred to as consumed at present. Now the 

 smokeless fuel which results from an extraction of 3333 

 cubic feet of gas per ton has a heating capacity fully 20 

 per cent, greater than common coal, and 10 per cent, 

 greater than coke. This gives us the exact equivalents 

 of the 5,000,000 tons of fuel at present in use. 



So far the account as regards the fuel available for the 

 community balances. We may now deal with the differ 

 ence in value between 16 and 24-candle gas. As the 

 value of the gas varies directly as its illuminating power, 

 the calculation is very simple. If we take the average 

 price of i6-candle-gas to be 31. M. per thousand cubic feet 

 we shall find the total value of the 20,000,000,000 consumed 

 in London to be 3,500,000/., but as we have by my 

 scheme the same quantity of 24-candle-gas, the value will 

 be increased to 5,250,000/. ; here then we have an annual 

 sum of 1,750,000/. to place to the credit of the system. 



Turning now to the by-products : seeing the gas 

 companies by the new arrangements would subject three 

 times the quantity of coal to the heat of their retorts 

 during the period when the tar and ammoniacal liquors 

 pass oft" most rapidly, I do not think I am wrong in 

 estimating the yield at double its present amount. Taking 

 this upon the tar and ammonia to yield 3^-. 9</. per ton of 

 coal, we find the total value of these by-products to be, 

 at present, on the supposed consumption by the gas 

 companies of 2,000,000 tons of coal per annum, 375,000/. 

 This being doubled under my scheme, an additional sum 

 of 375,000/. must be placed to its credit. 



But the basis upon which we have hitherto been 

 arguing is that the gas companies under the proposed 

 scheme are getting their coal for nothing. We have 

 been supposing that the community become the pur- 

 chasers of 6,000,000 tons of coal and hand it to the gas 

 companies. At present London only pays for its general 

 consumption on 4,000,000 tons of coal and 1,000,000 tons 

 of coke. Let us now suppose that the companies pay the 

 same sum annually that they do at present for their coals; 

 if so, they would pay upon 2,000,000 tons, or an annual 

 amount of 1,600,000/., if their coals cost 16^-. per ton. 

 From this falls to be deducted the money they at present 

 draw from their sales of coke, which, when taken at ds. 

 yer ton of coal carbonised under the existing system, still 

 leaves a sum of 1,000,000/., which they could afford to 

 pay per annum for the use of the 6,000,000 tons of fuel 

 as proposed in my scheme. We will now take the total 

 payments of the community for their coal to be upon 

 6,000,000 tons, for which we will further suppose they 

 pay at the rate of i6j- per ton first cost. This would 

 amount to 4,800,000/ per annum. From this falls to be 

 ded_cted the 1,000,000/. contributed by the gas com- 

 panies for the use of the fuel, also the 1,750,000/. charged 

 on the difference between the 16- and 24-candle gas 

 already referred to, also the sum of 375,000/. of additional 

 income from the by-products. This would leave a net 

 sum paid by the community for its fuel under my scheme 

 of 1,675,000/. Under the present system they have to 

 pay, say i6.f. per ton on 4,000,000 tons of coal, and say 

 \zs. per ton on 1,000,000 tons of coke. This makes in 

 all the sum of 3,800,000 per annum. Here then we have 

 a balance in favour of my scheme of 2,1 25,000/. annually. 

 This may be taken as the yearly value of London smoke, 

 which I propose to convert into useful products by the 

 plant at priscnt in use. 



I have only in conclusion to say one or two words about 

 the efficiency of the scheme as regards the fuel. It lights 

 easily, it gives oft' no smoke, it makes a cheerful fire, it 

 "ives out more heat than either coal or coke, it will be 

 cheaper per heat-unit than the coal at present in use, 

 London would become a smokeless city, and all that 

 would fall to be deducted from the sum of 2,125,000/. per 

 annum would be confined to a few items, such as the cost 



