January 5, 1917. THE COLLIERY GUARDIAN. 23 showed ;an (advance of 2s. 6d., and small stuffs Is. per ton on the month. A steady tone existed during the first two weeks of November. Demands gradually increased, but collieries were, unfortunately, not in a position to enlarge outputs accordingly, owing to a shortage of labour. About the middle of the month markets again took an easier turn, and the situation, on the whole, was unsatisfactory for the time of the year, values of ells in W-est of Scotland, best steams in the Lothians, and all classes, with the exception of first-class steams, in Fifeshire, suffering depreciation. Conditions were slow to improve, collieries, now found business difficult to negotiate, and outputs were accumulating. Prices all round showed considerable fluctuation. For instance, ell coals which had risen to 28s. now receded to- 25s. 6d., screened steam coal in the Lothians dropped 4s. 6d., and secondary qualities 3s. per ton, whilst screened navigations in Fife- shire were 6 s., and unscreened 5s. down, with first -class steams 4s. 6d. per ton cheaper. The variableness which had characterised the trade throughout'the year continued during the month of December. Owing to- the tonnage position, some classes .. of coal, and particularly ells, had difficulty in disposing of productions, and occasional stoppages took place. The Lothian collieries were also! (short of prompt orders, and the strongest feature in the market was the sus- tained demand for screened navigations and first-class Fifeshire steams. The end of the month arrived with- out much alteration in the general situation. The market in the "West of Scotland showed continued quiet- ness, wTith easier tendencies. Reports, however, from the Lothians- and Fifejshire were brighter. On viewing the trade of the year, two distinct periods stand out. During the first six months business was very satisfactory. Collieries had heavy bookings for all sizes and qualities at firm prices, whilst any free coal : realised extreme values. The effect of the war restric- tions was keenly felt throughout the latter half of the year, and, during this period, it was pretty much la case of up to-day and down to-morrow. Outputs were in excess of demands, whilst the scarcity of tonnage -and the difficulty in securing licences played havoc with the export trade. Generally speaking, however, despite, these drawbacks, collieries may be considered to have had a comparatively good year. Meantime, the situa- tion is full of uncertainty. Though the Government action with regard to State control has not yet been extended to Scotland, this may come at any moment, and collieries are loth to enter into- contracts even over ; the opening months of 1917. Moreover, it seems hardly ■ possible that the tonnage scarcity will be overcome, and ' the general position is not improved by the excess of ; production over consumption. In these days of con- : stant. changes, it is obviously unwise to attempt a prophecy, and though present indications are certainly not hopeful, many things might occur within the imme- diate future calculated to alter the whole course of business. CURRENT SCIENCE Steam coal Ell ........ Splint...... Treble nuts Double ,, Single „ F.o.b. Glasgow. January 1916. d. 0 to 6 0 „ o „ 0 „ 6 „ December 1916. s. d. s. d. s. d. 22 0 ... 19 0 to 25 0 22 0 ... 19 6 „ 24 0 30 0 ... 23 0 „ 32 0 6 6 0 21 19 19 23 6 22 0 21 0 Best screened steam coal Secondary qualities .. Treble nuts........... Double „ ............. Single „ ............. s. ... 18 ... 21 ... 23 ... 21 .. 19 ... 18 F.o.b. Leith. January 1916. d. s. 0 to 21 0 0 0 0 s. 20. 19 21 19 16 F.o.b. Methil or d. 6 6 0 6 6 December 1916. d. 0 6 0 0 6 s. 26 24 25 22 19 Best screened navigation coal................... Unscreened ............ First-class steams..... Third-class steams .... Treble nuts ......'.... Double „ .............. Single >> ............. „ 19 „ .22 „ 19 „ 18 Burntisland. January 1916. d. s. 0 to 26 0 „ 24 0 „ 23 16 6 „ 17 21 0 ,, 22 18 6 „ 19 17 0 ,, 17 Wages. s. 25 23 22 d. 0 0 0 6 0 6 6 December 1916. d. s. 0 to 34 0 „ 29 0 „ 30 22 0 0 to 25 22 0 21 0 s. 30 27 29 .. 23 d. 0 0 : 0 6 The wages of miners in Scotland have been advanced on three .occasions during the year—3d. in April, 6d. in June, .and 6d. per day in September—and now amount to 10s. per dav in most districts. An application for an advance of Is. per day is, meantime, under consider- ation. The aggregate shipments from Scottish port’s for the year reached the total of 9,859,291 tons, compared with 11,219,481 tons in 1915, a decrease of 1,360,190 tons. West of Scotland shipments are down 620,198 tons, the Lothians less by 257,162 tons, and the Fifeshire returns lower by 482,830 tons. (Continued on page 32.) Production of Dutch Coal.—From a report by the Govern- ment Board of Coal Mines, it is learnt that the total quantity of Dutch coal raised in 1915 was 2,263,00-0 metric tons, being an increase of 334,465 metric tons as compared with 1914. On January 1, 1916, the number of workers had risen to 11,718, being an increase of about 30 per cent. . A new Government mine, the Hendrite, has begun producing both steam coal and gas coal of superior quality. The Maurice mine, which is being opened up, is also to produce gas coal. Prospecting has shown that the coal in the seams of Southern Limburg is more than sufficient to provide for the total Dutch coal consumption during a.couple of centuries. Explor- ations have also shown that still larger coal areas exist in northern parts of the province. Cable Losses at High Frequencies. Messrs. Edwin F. Northrup and R. G. Thompson (Journal of the Franklin Institute) give the following conclusions from the tests carried out by them:—In a cable the strands of which are parallel, the loss is appreciably greater than it is in a solid wire having the same cross-section; and, surprising as it may appear, if this same cable is very much twisted, so that the wires lay in concentric spirals, the loss decreases 50 per cent, or more and* becomes less than in a solid wire. The tests appear to show that the more the cable is twisted the greater is the reduction in the loss. With the exception of the case just mentioned, the alternating-current resistance of a cable is less than that of a solid wire of the same cross-section. The smaller the individual wires and the better tliey are stranded or braided and the more perfectly they are insulated from each other, the more nearly does the alternating current resistance approach the direct-current resistance for a given cable. It is, further, important that individual wires should be stranded or braided, so that in passing along the cable an outside wire becomes an inside wire, and 'then again vice versa. Well-insulated cable-strands are obtained by using enamelled wire, though good insulation may be partially obtained by thoroughly treating the cable with an insulating varnish. The authors’ tests seemed to indicate that the decrease in loss obtained by using enamel-insulated wire in cables would hardly warrant the extra cost of this kind of insulation, particularly in cases where only a.portion of the total current which flows is high-frequency current. A case of this character is where the secondary of a high-tension transformer feeds an oscillating circuit, some of the high-frequency oscillating current finding its way into the secondary winding of the transformer. Analysis of Benzol First Runnings. In a paper read before the Society of Chemical Industry, Messrs. P. E. Spielman and F. B. Jones reported on experiments carried out in order to ascertain whether the method they'had already proposed for the analysis of commercial benzols was applicable to first runnings. This fraction differs from the benzol fraction mainly in containing up to 10 per cent, or 15 per cent, (and rarely as much as 65 per cent.) of carbon bisulphide; and up to 15 per cent, paraffin, together with very small proportions of a number of other substances. From a known mixture it was found that even 65 per cent, of carbon bisulphide gave a distillation test corre- sponding to the amount of toluene added (5 per cent.) within the limits of accuracy of the earlier benzol analysis. It was found, further, that water-soluble substances were insufficient in quantity to affect estima- tion by specific gravity, and also that a severe washing with sulphuric acid to remove other impurities did not cause alteration. The method previously described can, therefore, be applied directly to the evaluation of benzol first-runnings wirh the following modifications:— 1. Carbon Bisulphide.—The estimation of a high percentage of carbon bisulphide is most conveniently ; carried out by diluting the sample with up to five times its volume of benzene, which has been previously purified from any carbon bisulphide that it may contain. 2. Paraffin.-—The specific gravity of the paraffin of this fraction is 0’700. If the percentage of paraffin is : such that it lies outside the graph (given in connection with the original method) its quantity can be determined most easily by employing the simpler of the two benzol : graphs, ascertaining the specific gravity of the benzene- toluene mixture by its means, and determining the difference between this and that of the sample under examination after removal of CS2; the resulting difference is then. evaluated by means of the paraffin graph in the present paper. Further, it becomes necessary to take into considera- tion the percentage of carbon bisulphide present and to correct the quantity of paraffin found by differences of gravities. If, for instance, 10 per cent, of carbon bisulphide is present, the quantity of paraffin found will be that present in 90 c.c. of liquid, and the value, therefore, will have to be diminished in the ratio of 90 :100. In general, paraffin (true figure) = paraffin found multiplied by the fraction where x is the per- centage of OS 2. The following examples of known mixtures indicate the mode of employment:— (1) Mixture taken: 4 per cent, toluene, 3 per cent- paraffin, 12 per cent. CS2, 81 per cent, benzene. Distilla- tion of 100 c.c. up to 90 degs. Cent, gives 97’5 c.c.; equivalent to 3’6 per cent, toluene. Specific gravity after removal of CS2 : 0’8762. Junction of 3’6 per cent, toluene with gravity 0’8762 line is at 4’3 per cent, paraffin. Specific gravity of original sample: 0’9205. Specific gravity after removal of CS2 : 0’8762 — 12’5 percent. CS2. In order to obtain a correct value for the paraffin, the point representing the observed percentage (in a graph given in the paper) is moved upwards continuously, equidistant from the continuous and then discontinuous straight lines, until it reaches the point representing ’ the carbon bisulphide percentage : this point gives the correct value of 3’8 per cent, paraffin. (2) The mixture taken consisted of:—4< per cent, toluene, 11 per cent, paraffin, 50 per cent, carbon bisulphide, 35 per cent, benzene. Distillation of 100 c.c. to 90 degs. Cent. , yields 97T c.c. =4 per cent, toluene. As the mixture had a gravity of 1’0426, which is outside the graph, exactly 15 c.c. was diluted five times—i.e., to 75 c.c., with pure benzene. The specific gravity of this AND TECHNOLOGY. mixture 0’9150, the specific gravity after removal of CS2 : 0’8794 = 10 per cent. CS2 = (5 x 10) 50 per cent, on the original. The junction of 4 per cent, toluene and the 0’8794 line is at 2’6 per cent, paraffin; this figure corrected as before shows 2’3 per cent, paraffin, which equals (5 x 2’3) = 11’5 per cent, on the original. For high percentages of carbon bisulphide and paraffin the results will be less accurate than those obtained in the analysis of benzols, but, at the same time, there are no serious deviations from, the true values. Fresh Liquid Pitch for Briquette-making. According to Engineering, a big plant for briquette- making with the aid of the hot liquid pitch delivered by rail direct from the tar works, is being erected at the Hohenzollern Colliery near Beuthen, in Upper Silesia, which belongs to the estates of the Counts of Schaffgott. The- conveyance of liquid pitch in special tank-wagons by rail was tried first in August 1914, in the Essen district, when ordinary boiler tanks of 15 tons capacity were used. The tanks had only 3 miles to travel by road, but with charging and discharging the tanks the operations took seven hours; yet there was a saving in material and cost. For the plant now being completed in Silesia, the State railway line is to be utilised, and the consent of the Government was readily granted, subject to the addition of certain safety appliances to the tank-wagons. The process adopted is that of Fohr- Kleinschmidt, which, worked on the old plan, starting with dry, cold pitch to be melted, was a little more economical than other processes, but promises a con- siderably increased economy when starting with liquid pitch on the new plan. In 1913 Germany produced 5,823,776 tons of coal briquettes (not including lignite briquettes), containing about 400,000 tons of pitch— 7 per cent, on an-average. Different briquette processes required from 5 to 9 per cent, of pitch, and the prices were, before the war :—Lignite briquettes, 1T0 mk.; coal briquettes, 2’50 mk. to 3 mk.; pitch, 5 mk., each per 100 kilogs. It might be thought that liquid pitch and powdered or disintegrated coal might be run directly together in briquetting; but such attempts only yield a lumpy product devoid of strength. . By the Fohr-Kleinschmidt process the cold pitch as supplied, without fine disintegration, is heated first to 100 degs. Cent.; the thick fluid is then transferred to a melting drum kept at 130 to 170 degs., from which the thin liquid flows into a receptable to be further heated ' and sprayed by means of steam or compressed air. The sprayed particles congeal in a mixing drum, while still floating in the air; in this condition the pitch, forming a sooty dust, meets the finely-disintegrated coal and is mixed with it in slowly-revolving drums, which are fitted with stirring and lifting devices.- The mixture passes into kneading apparatus, and is pressed into briquettes at temperatures ranging from 50 to 80 degs. Cent. There were difficulties to be overcome, of course, in this process; but the Engelsburg Colliery of the Verein fur Bergbau und Stahlindustrie at Bochum has eight presses at work, yielding some 600 or 700 tons of briquettes daily. The pitch consumption has been reduced by 1 per cent, through the adoption of the Fohr-Kleinschmidt process, and the hot pitch will effect a further reduction in cost. There will be less waste, no need for disintegrating and remelting the pitch, and several operations will be much simplified. The emptying of the tanks by compressed air takes 15 minutes. The pitch to be used in the new plant in Silesia is distilled at a temperature of 250 degs. Cent. Softer pitch containing tar oils would be suitable for briquette-making; but tar oils cannot be spared at present; the price of pitch was 50 marks in Germany last summer, instead of 5 marks before the war. COAL MINING IM VICTORIA. The annual report of the Secretary for Mines, Victoria, for the year 1915 has just been issued. The production of coal was 588,104 tons, valued at the mines at £274,770, showing a decrease of 29,432 tons on the output for the previous year. Employment was given to 1,303 men. The State Mine, Wonthaggi, produced 528,922 tons, the Jumbunna Company, Jumbunna, 28,160 tons, and the Austral Company, Korumburra, 16,228 tons. The Melbourne and Altona Company raised 2,864 tons of brown coal at Altona. The. State Coal Mine, after allowing £33,000 for depreciation and £10,800 to the Sinking Fund, showed a net surplus of £10,369 for the financial year 1914-15. The total output to the end of 1915 was 2,730,984 tons, worth £1,188,364, leaving an estimated quantity of 19,750,000 tons yet to be extracted. The number of men employed was 1,130, and the average earnings of the miners was 14s. per day, the mine working 256 days for the year. The McBride Tunnel is in full operation, producing 450 tons per day. Electricity is practically the only motive power now in use. In coal mines two persons were killed by collision with skips and one by explosion of a, charged hole. In addition, 20 men were seriously injured. The number of accidents reported to the Coal Miners’ Accident Relief Board was 257, including two fatalities. There are now on the funds five disabled miners, 15 children and 10 women. The allowances paid during 1915 amounted to £1,048. The contributions by em- ployees total £7,652; by employers, £3,900 ; and by‘ the State, £3,794; £4,288 has been paid to disabled miners and others and £8,950 is invested in Government loans. The decrease in revenue is, no doubt, due to a great extent to the many enlistments from the ranks of the miners with the Expeditionary Forces, and the consequent diminution of per capita contributions,