July 17, 1914. THE COLLIERY GUARDIAN. 137 tight and are not adaptable to irregular alignment. Obviously, the cost of such pipe is considerably greater than that of the plain pipe. Where lines are installed with the probability of remaining in one place for a considerable period, especially those along travelling ways or air courses that are constantly under inspection, cast iron pipe (fig. 7, D) is extensively used. This pipe possesses the advantage of wearing with a continuously smooth surface and offer- ing little resistance to the flow of the filler. The types of connections most extensively used are the flange and the bell-and-spigot. The bell-and-spigot connection is used more frequently for filler pipe, whereas the flange connection is used almost exclusively for pump-column lines. The bell-and-spigot connection is made tight by the use of oakum packing or short pieces of old hemp rope, and is firmly secured with white-pine or other soft wood wedges. The abrasion of the filler keeps the inside of the pipe smooth at all times, so that the frictional resistance, it is claimed, is considerably less than in wooden pipe. The feature of cast iron pipe that gives it wide adaptability is its being made in 12 ft. lengths, which, although necessitating the expense of frequent connections, afford physical advantages, such as the possibility of irregular alignment, that are not obtainable with other metal pipes, which are made in longer lengths, usually about 20 ft. The life of cast iron pipe is about twice that of wooden pipe and about six times that of steel or wrought iron pipe. Wood-lined cast iron pipe has been used in several mines, particularly on slopes, but its use is not common. The pipe has a cast iron flanged shell with a wood stave lining. When water is introduced, the wood lining tends to expand or swell, and thus make a firm contact between it and the inner wall of the cast iron shell. The pipe possesses the wearing and acid-resisting qualities of wood pipe and of ordinary cast iron pipe, but by reason of the expensive outer shell and the rather short life of the wood lining, unless it is carefully -15* c Soft-wood j wedges Hemp packing or cement mortar I Pine wedges Hemp packing, D E Figure 7.—Connections of metal and terra-cotta pipes. A, screw coupling; B, plain sleeve; C, standard flange coupling, 6 bolts; D, cast-iron bell-and-spigot connection; E, terra-cotta pipe connection. and frequently inspected, many blockages occur on ac- count of the lining wearing out, so that the general application of this form of pipe can not be said to be probable. In places where there is slight danger of damage from falls of roof or other external sources of injury, the use of terra-cotta pipe (fig. 7, E) may be safely and economi- cally adopted, especially if there is no back pressure on the line. Terra-cotta pipe, however, offers considerable frictional resistance on account of the rapid abrasion caused by the filler, which soon wears off the smooth glaze. Especial care must be exercised and close super- vision enforced so that the pipe will be turned in sections at proper intervals to obtain the maximum wear. The pipe can be advantageously used on all descending lines in flat workings where the filler is to be conveyed directly to the bulkheads. Porcelain-lined pipe has been extensively used with excellent results in European plants, although in some mines it has not been so successful and has been replaced by plain metal pipe. Owing to its high price in America and to the difficulties of manufacture the cost of this type of pipe is so great as to make its use impracticable for hydraulic mine filling in the United States under present condition. In order to avoid the heavy expense of renewing elbows and other bends in filler lines, a remedy was sought in the use of glass pipe, particularly for bends of 45 degs. to 90 degs. The experiment, however, has not proven an entire success, and the use of glass pipe will probably be desirable only under special conditions. (To be continued.) Partnerships Dissolved.—The London Gazette announces the dissolution of the following partnerships :—J. C. Fell and R. W. James, consulting engineers and chartered patent agents, Queen Victoria-street, London, under the style of Fell and James; F. Holmes and T. Walmsley, engineers and tool makers, Neill-street, Armley-road, Leeds, under the style of the Leeds Vise Company; H. F. Fussell, and T. A. Fussell, coal merchants and estate agents, West Ealing- broadway, W., under the style of Fussell Brothers. Immingham Coal Exports. — According to the official returns for week ended July 10, the exports of coal from Immingham totalled 32,012 tons to foreign destinations, and 4,205 tons to coastal ports, against 3,981 tons and 2,210 respectively during the corresponding week last year. Ship- ments Foreign : To Cronstadt, 7,491 tons: Delfzyl, 554’ Flensburg, 1,927; Gaddelgo, 686; Hamburg, 6,685: Horsens, 1,271; Pernau, 1,504; Reykjavik, 546; Riga, 2,035; Rotter- dam, 1,676; Savona, 6,211; and Simhamn, 1,426. Coastal • To Lerwick, 640 tons; and London, 3,565. SOLVENTS OF COAL?4 With the idea of establishing a chemical classification of coals by the aid of solvents, the author examined the action of various solvents on a number of coals from the Loire coalfield : Montrambert coal, bituminous gas coal, semi-bituminous coal, and lean coal. Action of Various Solvents. — The solvents, alcohol, ether, benzol, toluol, aniline, and nitro-benzol (50 cc. in each case) were allowed to act on 10 grammes of Mont- rambert coal for 24 hours at the ordinary temperature, and for three hours at the respective boiling points of the solvents. On evaporating to dryness a fraction of the filtered extract, the following percentage proportions of extractible substance were obtained :— Alcohol (96 per cent.). Ether At ordinary temperature. Per cent. .. 0’076 0’059 At boiling point of solvent. Per cent. 0’0167 Benzol .. 0’080 0’191 Toluol .. 0’078 0’190 Aniline 2’250 .... 12’050 Nitrobenzol .. 1’410 3’190 Action of Aniline.—The solvent action of aniline near its boiling point being characteristic, a detailed investi- gation of the phenomenon was carried out. Eight hun- dred grammes of Montrambert coal, powdered, dried at 100 degs. Cent., and passed through a No. 20 screen, were extracted with 4 kilos, of pure aniline at a tem- perature of 180 degs. Cent., in a 1-litre flask charged with 100 grammes of the coal and 500 grammes of aniline, the heating being continued for four hours. After filtration in a partial vacuum, the filtered liquid, on cooling, deposited a blackish powder, which was removed by a second filtration. To isolate the dissolved matter, the aniline may be expelled by a current of steam; but it is preferable to saturate the aniline with hydrochloric acid (21 degs. Be), diluted with its own volume of water. The blackish flocculent precipitate obtained was collected on a filter, thoroughly washed with distilled water, and dried in the drying oven at 90 degs. Cent. The weight of the dried precipitate was 80 grammes. Both this extracted substance and the insoluble residue of the coal (said residue being washed with dilute HC1, followed by distilled water, and dried at 100 degs. Cent.) were subjected to ultimate analysis, and to the coking test, with the following mean results :— Coal insoluble in Coal dissolved by hot aniline. hot aniline. t Gross. A Nett (ash deducted.) i Gross. Nett (ash deducted). Per cent. Per cent. Per cent. Per cent. Carbon .. 81’50 . .. 83’94 ... 83’50 . .. 84’00 Hydrogen .. 4’90 . 5’05 5’60 . 5’63 Nitrogen.. . 1’70 . .. 1’75 ... 1’37 . 1’38 Sulphur .. . 1’10 . 1’13 ... 1’05 . .. 1’06 Ash .. 3T0 . — 0’46 . — Coke 72’05 69’69 The coke furnished by the insoluble coal was powdery, that from the dissolved coal substance being agglom- erated and very tumid. Comparison of Different Coals.—Three different kinds of Loire coals—bituminous, semi-bituminous, and lean —having the following characteristics, were treated with hot aniline :— Water. Ash. P. cent. P. cent. Bituminous gas coal 1*74 ... 12’53 . Semi-bituminous „ 1’57 ... 9’06 . Lean „ 1’53 ... 11’27 . Coke. P. cent, , 73’88 81’10 Coke (ash deducted), P. cent. ... 70’1 ... 79’2 91’03 ... 89’9 To ascertain the relative solubility in aniline, one to two grammes of coal and 25 grammes of pure aniline (b.p. 182 degs.) are placed in a 125 cc. flask provided with a cork traversed by a drawn-out bent tube for the removal of moisture. Boiling is con- tinued for an hour, and the liquid is passed through a tarred filter after settling. The residue is boiled up again with 25 cc. of aniline for a few minutes. Two supplementary washings are needed for completing the extraction of lean coals, three being requisite in the case of bituminous coals. * L. Vignon. Comptes Rendus, The residual coal is afterwards washed with hydro- chloric acid (21 degs. B£), diluted with twice its own volume of water, and then with distilled water, and is finally dried and weighed. Results :— Solution, Initial After qa]„kia after weight. extraction. ’ deducting ash. Grammes. Grammes. P. cent. P. cent. Bituminous gas coal ...... 1’46-1’68 ... 1’12-1’29 ... 23’40 ... 26’8 Semi - bitu- minous coal.. 1’17-1*32 ... 1’09-1’23 ... 6’58 ... 7’2 Lean coal ... 2’17-2’01 ... 2’14-2’01 ... 1’56 ... 1’8 Action of Pyridine at Boiling Temperature (114 degs. Cent.).—Bedson (J. Soc. Chem. Ind., v. 27. (1908), p. 14) has mentioned the solvent action of pyridine. The author treated one gramme of gas coal, dried at 105 degs. Cent., with 50 cc. of boiling pyridine for an hour, then filtering and washing the insoluble matter thoroughly with boiling pyridine, followed by boiling alcohol, the residue being finally dried and weighed. The loss in weight amounted to 17’3 per cent. Action of Chinolin at Boiling Temperature (238 degs. Cent.).—One gramme of the same gas coal, dried at 105 degs. Cent., was treated with 50 cc. of boiling chinolin, the insoluble residue being filtered off, washed, dried, and weighed. The loss in weight amounted to 47-3 per cent, of the original substance. The extracted material was isolated by treating the solution with a slight excess of dilute hydrochloric acid, and filtering to collect the precipitate, which was then washed with distilled water. The coking test, applied to the soluble and insoluble portions of the coal, gave the following results :— Insoluble. Soluble. Coke, per cent.......... 77’90 ..... 66’97 The coke from the insoluble portion was dusty, whilst that from the soluble portion was caked and tumid. Summary.—(1) Aniline affords means of chemically classifying the coals technically known as bituminous, semi-bituminous, and lean coals. The bituminous coals contain relatively large amounts of substances soluble in aniline, the lean coals very little. (2) The substances soluble in aniline are precipitated by acids. (3) Com- parison of the insoluble portion of bituminous coals with the substances thrown down from solution in aniline, shows that the soluble portion is richer in hydrogen, lower in ash constituents, and furnishes a coke which is caked and tumid, instead of being dusty. (4) The bitu- minous coals yield up a considerable amount of matter to boiling chinolin, a phenomenon which will be examined separately. COLLIERIES AND INCOME-TAX. Hire Purchase of Wagons. [From a Correspondent.] In the assessment of income-tax on collieries allow- ances were, up to a recent date, refused in respect of that part of the periodical payments in respect of hire- purchase of wagons which represents hire. In Darn- gavil Coal Company v. Francis it was held that a deduc- tion was permissible in respect of that portion of the payment which constitutes hire as distinct from purchase of the wagons. The Mining Association of Great Britain made repre- sentations on the matter to the Board of Inland Revenue and the latter formulated a scheme, which was approved by the Mining Association, and has come into operation this year, and the allowances now to be made are governed by the following rules :— 1. The lessees of wagons under a hire-purchase agree- ment shall furnish to the Surveyor of Taxes a copy of the agreements, together with a certificate from the wagon builder, or other satisfactory evidence as to the price at which the wagons would have been sold for cash at the date of the agreement, hereinafter referred to as the initial value. 2. The difference between the initial value and the aggregate amount payable under the agreement shall be treated as “ hire,” and allowed in equal annual amounts spread over the term of the agreement. 3. Depreciation shall also be allowed on the initial value from the beginning of the agreement in accord- ance with the provisions of the Income-Tax Acts at a rate to be settled by agreement between the lessee and the Crown or by appeal to the Income-Tax Com- missioners. 4. In the event of any wagons under a hire-purchase agreement being purchased outright before the termina- tion of the agreement, or being returned to the lessor, the allowance for hire shall cease from the date of such purchase or return, and if returned the allowance for depreciation shall thenceforth cease. 5. If any such wagons shall be “ re-financed ” the allowance for hire under the agreement thus terminated shall cease, and a fresh allowance shall be made for the period of the new agreement to be determined bv taking the difference between the amount at which such wagons are re-financed at the date of the new agreement and the aggregate amount pavable under the new agree- ment, and spreading the said difference evenlv over the term thereof. The allowance for depreciation to be continued without reference to the new agreement. 6. Where any wagons are the subject of hire-purchase agreements current at the date of this scheme or during any of the preceding years upon the average profits of which any income-tax assessments are computed, and no allowances for hire have been made in respect of the payments under such agreements, the amount which would have been allowable annually for hire had this