THE COLLIERY GUARDIAN. 491 March 7, 1913. _________________________________________________________________________________________ Trade. Net output of firms furnishing particulars. Fuel consumed by firms furnishing particulars. Amount. Percentage of total net output of the trade. Coal. Coke. Paper, printing and allied trades :— Paper trade £ 3,447,000 75-9 Tons. 1,501,859 Tons. 12,063 Printing and bookbinding trades—private firms and companies 10,363,000 • 67-5 71,347 7,587 Printing and publishing of newspapers and other periodicals 7,075,000 79’8 34,899 4,982 Typefounding, stereotyping, engraving and die-sinking trades 365,000 54-8 2,687 238 Manufactured stationery trades—private firms and companies 1,355,000 68-5 9,016 2,367 Cardboard box trade ... . 778,000 69-8 5,377 1,126 Pen, pencil, and artists’ materials trades 290,000 59-2 7,105 342 Ink, gum, and sealing wax trades 348,000 75-2 8,053 529 Trade photography 55,000 46’2 245 114 Total 24,076,000 717 1,640,588 29,348 General Post Office (Savings Bank Department) printing and envelope factories . 4,652 100 Ordnance Survey Department 63,908 100 105 161 Total 68,560 100 105 161 Leather, canvas and indiarubber trades — Fellmongery trade 69,000 47-0 5,269 1,099 Leather trade (tanning and dressing) 2,273,000 67 1 156,890 10,374 ’ Saddlery and harness trade 259,000 24-0 5,496 2,223 Travelling bag and fancy leather goods trades 147,000 28-1 1,063 144 Canvas goods and sack trades 292,000 57-4 11,309 942 Indiarubbt-r trades 2,164,000 72-7’ 221,123 3,367 Total 5,204,000 60-4 401,150 18,149 Timber trades:— Timber trades 4,516,000 70-2 207,893 10,8Q2 Furniture,, house furnishings, and upholstery trades— private firms and companb s 4,892,000 52 6 121,076 5,816 Woollen crate, case, box, and trunk trades ■ 728,000 623 27,423 985 Carriage, cart, and wagon trades 1,48 <,000 49-6 21,941 10,149 Brush tradn 449,000 523 4,783 531 Coopering trade 228,000 50'7 10,114 415 Basket and wickerwork trade 29,600 120 98 21 His Majesty’s Office of Works : Blind and Carpet Stores — — — — Total 12,325,000 57-5 396,328 28,809 Clay, stone, building and contracting trades :— Brick and fireclay trades 3,980,000 72-9 2,826,867 52,961 China and earthenware trades 3,836,000 82-9 1,143,342 16,610 Cement trade 1,702,000 87-1 708,054 600,531 Asbestos and bo ler coverings trades 244,000 76-0 8,987 3,181 Glass, stone, roofing fidts, and miscellaneous trades 2,611,000 54-8 646,109 44,597 Building and contracting trades 31,225,000 72-7 383,828 46,266 Naval establishments at home (buildings) 318,550 100-0 2,033 — Office of Works and Public Buildings — — — — . The Board of Public Works, Ireland 38,406 100’0 935 28 Total 43,954,956 72-7 5,720,155 764,174 Miscellaneous trades: — Scientific instruments, apparatus and appliances trades... 1,079,000 70’3 10,677 2,828 Ivory, bone, horn, picture frame and fancy articles trades 479.000 46’6 16,324 541 Musical instruments trades 633,000 59-9 6,709 2,015 Billiard table and sports requisites trades 344,000 52’3 3,160 676 Toys and games trades 43,000 39-1 387 87 Wigmaking trade — — — — Total 2,578,000 58’0 37,257 6,147 Letters to the Editor. The Editor is not responsible either for the statements made, or the opinionp expressed by correspondents. All communications must be authenticated by the name and address of the sender, whether for publication or not. No notice can be taken of anonymous communi- cations. Asreplies to questions are only given by way of published answers to correspondents, and not by letter, stamped addressed envelopes are not required to be sent. carbonised in the year of return for gas production, for transport purposes other than the generation of and that in addition 438,700 tons of coke and 239,900 electricity. The following statement shows the quan- tons of oil were used in the production of water gas and tities of coal and coke consumed at engines at the for gas enrichment. It also appears from the returns J various classes of undertakings, the net output of the furnished by tramway and light railway companies that ( companies and authorities furnishing particulars being 42,400 tons of coal and 200 tons of coke were used 1 also given:— __________________________________________________________________________________ Net output of companies and authorities furnishing particulars. .. __________ Fuel consumed at engines. _____ Undertaking or authority. Amount. ___________ Gas undertakings:— (a) Companies........................................ (b) Public authorities................................ Waterworks undertakings.— (a) Companies....................................... (b) Public author ties................................ Electricity undertakings:— (a) Companies...................................................... (5) Public authorities................................ Local authorities, England and Wales .................. | Local authorities, Scotland ...................... ______ ■ Local authorities, Ireland................................ I Canal, dock, harbour, and similar companies ............ | Tramway and light railway companies .................. I His Majesty’s Post Office (telegraph and telephone under- takings) ............................................. The National Telephone Company....................... ! Percentage of total net output of undertakings Coal. Coke. £ 10,741,000 5,519,000 1,504,000 6,915,000 1,533,000 3,591,000 8,148,000 863,000 682,000 497,000 306,000 655,000 510,000 Per cent. 92*9 96'3 87’1 94’1 76’8 100’0 82-0 82’3 71’5 85-7 99’7 100-0 100-0 Tons. 28,913 30,382 171,694 364,171 797,023 1,973,066 403,943 70,070 12,930 39,507 118,514 38,219 Nil. Tons. 1,578,228 986,514 11,021 18,151 2,191 26,762 66,225 3,567 826 1,707 3,596 1,479 Nil. Total ................................ i 41,464,000 90-3 4,048,432 2,700,267 __________________________________________________________________________________________________________________ Midland Institute of Mining, Civil and Mechanical Engineers. — A general meeting of the members of the institute will be held at the Y.M.C.A, Hall, Eldon-street, Barnsley, on Wednesday, March 12, 1913, at 3.30 p.m. A note on “ An Electrolytical Method of Determining the Percentages of Various Gases in Mine Air,” by Mr. D. Bowen and Dr. Coplans, of Leeds University, will be read, and Mr. Harold C. Jenkins will read a paper on “ Some Recent Experiments with Internal Pressures in Pneumato- phores.” Mr. G. Blake Walker’s paper on “ The Generation and Use of Compressed Air in Mines” will be open for discussion. Manchester Geological and Mining Society.—The ordinary meeting of the members of the Manchester Geological and Mining Society will be held in the Geological Lecture Theatre, Beyer Building, at the Manchester Univer- sity, on Tuesday, March 11,1913, at5 30 p.m. The following papers will be read:—“Some Notes on the Microscopic Structure of Metals,” by Mr. Charles J. P. Fuller, F.C.S.; “ Firedamp in Coalmines,” by Dr. John Harger, M.Sc., Ph.D. (Heidelberg). A council meeting will be held in the Geological Laboratory, Beyer Building, Manchester Univer- sity, on the same day at 4.30 p.m. REVIEW OF 11 COAL AND THE PREVENTION OF EXPLOSIONS AND FIRES IN MINES.”* Str,—I consider it unjust that I should be subjected to all this unfair criticism, merely because I have written a decent, straightforward, readable book. If your reviewer is honest, why doesn’t he sign his name ? Surely he must know that that is the correct thing to do in a scientific review ? I hope, as a matter of justice, you will allow me to make a few remarks on your reviewer’s effusion. He states:—“ Dr. Harger propounds peculiar views as to the manner in which coaldust is deposited and raised into the air in a mine road.” Well, readers of the Colliery Guardian can examine the phenomena for themselves. It is not a matter of opinion, but a matter of fact, so no amount of argument will alter’it. Perhaps your reviewer does not often see the roadways of a dusty mine ? I may mention that, on re-reading a paper by W. C. Blackett on “ The Combustion of Oxygen and Coaldust in Mines ” (Trans. I.M.E., 1894), it appears that he, too, had “ peculiar views ” on the method of deposition of dust in the airways. In his concluding remarks in that paper he says, about the artificial mine experiments (which were then spoken of as possible):—“ Ventilation should be effected by a fan, and the air-current should be allowed to deposit the experimental dust.” (The italics are mine.) If this advice had been taken by those in charge of the Altofts tube experiments, how different the results would have been! When your reviewer talks about the “supposed fact ” that dust explosions always tend to travel against the air-current, he merely shows his ignorance of actual dust explosions which have occurred in mines, and probably a better acquaintance with the results obtained at the Altofts tube station. These latter, however, are regarded by practical men as little more than amusing firework displays—of little scientific value and of no practical importance whatever. Your reviewer says:—“We are tempted to ask whether Dr. Harger has ever observed any appreciable effect in removing dust when the ventilation is reversed.” My reply is, Yes, I have, and most other practical men have too. Mr. Knox says (Trans. I.M.E., vol. xliv., part 2, p. 340):—“The other points men- tioned by Dr. Harger for preventing or lessening the number of gob fires—the reversal of the air-currents at week-ends—was he thought a very sensible one. If that were done regularly a large percentage of the fine coaldust would be taken away by exhaustion up the upcast shaft. This plan has been attempted—he believed in some mines in the West of Scotland— during the last five or six months with what appeared to be very beneficial results.” If your reviewer is still sceptical I would suggest that he should ask Dr. Wheeler to try it for himself at Eskmeals tube. A further extract from your review reads: “ Dr. Harger also lays stress, as regards the initiation of explosions, on the minute amounts of .fine coaldust normally present in mine air and on the microscopic amounts of oxygen and other gases contained in this dust.” My reply is, Of course I do, and so does any other practical man who knows anything about actual mine conditions, who has observed the quantity and extreme fineness of this dust and who is acquainted with Prof. Bedson’s work on the (not microscopic) amount of gas in coaldusts. Again, your reviewer is led astray by the absurd procedure of the Eskmeals people who, you may remember, actually heated coaldusts at 110 degs. Cent, for an hour before trying their inflam • mability—a clear proof that they at least knew little, if anything, about the nature of coaldusts—some coaldusts if treated so for two hours would be found to be red hot inside the mass ! The same sort of thing permeates the whole of the review. It is also evident that your reviewer has not really read a great part of the book, or he would not ask questions about removal of carbon monoxide, and state that I had not prepared gas suitable for the purpose “even on the most modest scale,” for as a matter of fact this has been done and is described in the book. ____________________________________ * Colliery Guardian, February 14, 1913.