'838 THE COLLIERY GUARDIAN. Ap&il 17, 1914 firedamp. The third-phase flames are of a more dispersed character than those in the preceding tests. Fig. 6 is the flame of a 600-grammes charge which ignites fire- damp, and is of special interest as showing the influence of the vicinity of the gallery wall on the production of third-phase flames. Explosive D.—This is of the ammonium-perchlorate type. Fig. 7 shows the flame from a 100-grammes cart- ridge, and is remarkable from the fact that, in spite of the size and intensity of the flame, this charge does not ignite either firedamp or coaldust. With a 200-grammes charge in two cartridges arranged in line, the third- phase flames are completely circular, and there is a well-defined re-ignition of the gases near the lower part of the gallery wall. The mouth of the mortar can be seen in the midst of the central flame. This weight of charge ignites both coaldust and firedamp. A similar charge was fired with a nitro-toluene detonating cord having a velocity of detonation of 4,900 m. Apart from the central flame, through which the mouth of the mortar can be seen, nothing is visible but a few flames of the third phase. Fig. 8 is the flame of a charge of 200 grammes in two cartridges side by side. The highly luminous flame fills up most of the cross-section of the gallery, and readily ignites firedamp and coaldust. A very similar result was obtained with a 400-grammes charge, in four cartridges arranged in three rows. Explosive E.—This is of the ammonium-nitrate type, with addition of nitro-glycerine. The flames were from samples below the standard in respect of charge Umile. Fig. 9 is the flame of a 200-grammes charge, the cartridges being arranged side by side. This charge does not ignite firedamp. The influence of the lower part of the gallery wall on the production of third-phase flames can be clearly seen. A 400-grammes charge ignited firedamp, and highly characteristic re-ignition of the explosion gases in the lower part of the gallery can be seen. A 200-gramme charge, with the cartridges placed in line and fired with a nitro-toluene detonating cord, ignited firedamp. Dynamite Gomme No. 1.—The composition of this explosive is: Nitro-glycerine, 42’5 per cent.; guncotton, 1’5 ; sodium nitrate, 45’5 ; wood meal, 3’0; wheat flour 5’0 ; dinitrotoluene, 2*0 ; common salt, 0’5 per cent. A charge of 100 grammes will ignite both firedamp and coaldust; and both this charge and one of 300 grammes (fig. 10) give a central flame surrounded by a halo, together with third-phase flames. The halo is also found on reducing the percentage of oxygen in the surrounding air by the addition of firedamp ; but, on the other hand, the third-phase flames disappear. Fig. 11 shows the change produced in the flame of a 300-grammes charge by stonedusting the interior of the mortar ; and under these conditions the charge will not ignite firedamp or coaldust. Alsilite S.P.G.—This, which has a charge limite of 900 grammes, is composed of: Ammonium nitrate, 62 per cent.; sodium chloride, 22 ; trinitrotoluene, 11; and ferro-silicon-aluminium, 5 per cent. The flame of a 900-gramme charge consists merely of a small central flame and a few third-phase flames. Yonckite No. 106.—This explosive also has a charge limite of 900 grammes. It consists of: Ammonium nitrate, 30 per cent.; sodium nitrate, 15; ammonium perchlorate, 25; trinitrotoluene, 10; sodium chloride, 20 per cent. The flame (fig. 12) corresponding to a full charge is small, and the third-phase flames are of only slight luminosity. A 400-grammes charge, fired with a trinitrotoluene detonator cord, ignites firedamp. Permonite.—Like the two preceding explosives, this has a charge limite of 900 grammes, which gives a small central flame and a few slightly luminous third-phase flames. The phenomena are similar, but less pronounced, with a charge of 400 grammes. The use of a trinitro- toluene detonator cord lowers the charge limite to 200 grammes in presence of firedamp. Antigelde Surete.—This belongs to the same class as the preceding explosive, and has the same charge limite. Its composition is: Nitro-glycerine 25 per cent., sodium nitrate 20, dinitrotoluene 15, ammonium sulphate 5, cellulose and flour 35 per cent. The full charge gives only a slight central flame, in which the mouth of the mortar can be seen. Summary and Conclusions. The present report relating solely to preliminary tests, it would be premature to formulate any conclusions. These experiments call attention to the complex character of the phenomena of the explosion. It seems that the reactions proceeding in the interior of the mortar, at the velocity of the explosion wave, are frequently, if not always, incomplete, and only attain completion outside the mortar, with or without the intervention of oxygen. The discovery of this fact has led the author to differentiate between {V) flames of the first phase, which correspond to the reactions occurring inside the mortar during the passage of the explosive wave; (2) flames of the second phase, corresponding to the reactions occurring in the gases issuing from the mortar, and in which atmospheric oxygen takes no part ; and (3) flames of the third phase, which correspond to local centres of com- bustion—sometimes more or less general—set up in the explosion gases under the influence of atmospheric oxygen. In subsequent experiments an attempt will be made to determine the influence of the composition of the explosives, the compactness of the charge, the velocity of detonation and the special conditions of firing, on the production of these flames, as also to ascertain the danger to which these flames may give rise in connection with the ignition of firedamp or coaldust. Flames of the third phase can be observed on many of the photo- graphs—a fact which shows that the explosion gases often contain combustible gases outside the area of the central flame. Mixtures of air containing firedamp with the more or less combustible hot gases, possess different limits of inflammability, different calorific properties, and require different conditions of temperature for their ignition than is the case with mixtures of dust-laden air and the same hot gases. This explains why some explosives ignite firedamp more readily than coaldust, and vice versa. ■ It would be of great interest to learn whether the explosion phenomenon is equally complex when the explosives are fired in mining practice. Up to the present, shots fired in the Colfontaine gallery (connected with the Frameries experimental station) gave no! flame when stemmed and used for blasting in rock; but it should be mentioned that such shots have been fired only in loose, slightly damp schists. It is desirable to have photographs of shots fired in perfectly dry rock of varying degrees of hardness; and the collaboration of mineowners in this respect would be extremely useful. Such photographs would need to be taken systematically and continuously in headings and galleries. In some instances it would be useful to water the rock round the seat of the charge by forcing water under pressure into the shot-hole before charging. This precaution would probably reduce the risks of shot-firing considerably, and photographs of the flames produced by the shots under these conditions would give very useful indications. The photographs reproduced above reveal a new fact —namely, the influence of the vicinity of the gallery walls on the re-ignition of the explosion gases mixed with air. In this connection it is desirable to examine the effect produced on the safety of the explosives by providing an obstacle—such as a pit timber or projecting piece of stone—for the explosion gases to impinge against. It is not altogether impossible that such a cause may have given rise to the explosions of firedamp or coaldust produced by small charges of explosives which would have been harmless in other circumstances. The photographs also direct attention to the possible desirability of modifying the conditions of testing explosives in the gallery. It would be useful to prescribe that the permitted explosives should be made up in cartridges of uniform diameter—say, 30 mm.—and to test them in a mortar of the same diameter as an ordinary shot-hole intended for cartridges of these dimensions—say, 32 or 35 millimetres. In determining the charge limite under these conditions, it seems feasible to assume that blown-out shots would not produce flames more dangerous, as regards the ignition of firedamp, than shots fired in the steel mortar. Another result of the above experiments is to show the desirability of checking the quality of the permitted explosives by frequent tests, for the purpose of eliminating those which are most susceptible to the influence of slight modifications in the method of manufacture, and to enable manufacturers to ascertain which methods of preparation will ensure the most uniform quality of their explosives. Grimsby Coal Exports.—The exports of coal from Grimsby during the past week were as follows:—Foreign : To Bergen, 2,002 tons; Christiania, 104; Dieppe, 353; Esbjerg, 283; Gothenburg, 1,206; Hamburg, 987; Karra- beksminde, 572; Malmo, 4,001; Riga, 1,451; Rotterdam, 260; and Skien, 103; total, 11,322 tons. Coastal: To Chatham, 172 tons; and Falmouth, 240; total, 412 tons. During the corresponding week last year the totals were 22,498 tons foreign and 102 tons coastal. Hull Coal Exports.—The official return of the exports of coal from Hull for the week ending Tuesday, April 7, 1914, is as follows:—Amsterdam, 758 tons; Antwerp, 298; Assens, 792; Boulogne, 1,413; Barfleur, 180; Bremen, 907; Christiania, 1,204; Copenhagen, 285 ; Dieppe, 1,418; Danzig, 277; Ghent, 692 ; Hamburg, 3,731; Harlingen, 1,856; Halmstad, 1,637; Harburg, 1,130; Landscrona, 3,320 ; Reval, 1,862 ; Riga, 1,123 ; Rotterdam, 4,356; Rouen, 4,801; Trieste, 262; total, 32,302 tons. Corresponding period March 1913, total 84,334 tons. THE FINANCIAL RESULTS OF GERMAN COLLIERIES IN 1913. Some interesting facts are contained in the annual report issued by the Dortmund banking house of Stern Bruder in regard to the market in mining shares during 1913. At the beginning of the year, it is stated, the uncertainty of the political situation in Europe and the dearness of money to some extent counteracted the effects of industrial expansion that induced the Coal Syndicate to abandon the limit of output, and con- sequently this policy was not followed by the anticipated rise in share values. On the other hand, the first signs of industrial retrenchment were quickly reflected in the share market, notwithstanding the improvement in the political situation and the cheapening of money, which was progressive during the second half of the year. A record of highest and lowest prices is given, as well as the average quotation at the beginning and end of the year, for a number of the principal companies in West- phalia. Amongst the concerns showing an advance were the following:—Freie Vogel und Unverkofft, Graf Bismarck, Heinrich, Westfalen, Constantin der Grosse, and Friedrich der Grosse; whilst the following declined in value:—Langenbrahm, Mont Cenis, Dorst- feld, Graf Schwerin, Lothringen, and Unser Fritz. Generally, the situation may be stated as under :— Marks. On January 2, 1913, the shares of 35 com- panies quoted (not including those not producing coal) represented at the prices prevailing a value of .................. 467,960,000 On December 31, 1913, this value had declined to............................... 441,950,000 A decrease of............................... 26,010,000 To this must be added in respect of capital calls....................................... 15,850,000 Giving a total loss in value during 1913 of 41,860,000 The amount of funded debt, spread over 27 companies, was 153,814,902 marks, as compared with 140,341,500 marks in 1912 and 138,767,500 marks in 1911. The following companies have no mortgage indebtedness : — Carolus Magnus, Graf Beust, Graf Bismarck, Heinrich, Herman I./III., Rudolph, Ver Gliickauf, Westfalen, and Wilhelmine Mevissen, the three last having been recently started. Adding this sum, the total capital of the total capitalisation of companies whose shares are dealt in on the Essen Exchange on December 31, 1913, was 599,589,902 marks. The following table shows the net profits in 1912 and 1913 of the chief companies :— 1913. Marks. Name. 1912. Marks. Adler 759,104 . 676,005 Alte Haase 203,445 . 192,262 Blankenburg 83,822 . 107,179 Caroline 252,601 . 406,768 Carolus Magnus 789,228 . 738,136 Constantin der Grosse... 5,908,457 . .. 10,223,318 Dorstfeld 1,420,782 ., .. 1,811631 .. 8.416,089 E wald 6,444,145 .. Friedrich der Grosse ... 2,812,594 .. .. 3,758.606 Gottessegen 84 936 .. 159,620 Graf Bismarck 4,614,245 .. .. 5,880,461 Graf Schwerin 1,327,234 .. .. 1,707,658 Heinrich 615060 .. 906,940 Helene und Amalie 2,149,013 ., .. 3,158 746 Johann Deimelsberg ... 712,806 .. ,. 1,104,109 Konigin Elisabeth 2,952,126 .. .. 3,448.671 Konig Ludwig 3,635.577 .. .. 4 806,410 Langenbrahm 3,002,731 .. .. 3,276,610 Lothringen 3,284 492 .. .. 4,230,870 Mont Cenis 871,540 .. .. 1,764,278 Oespel 173,132 .. 323,837 Schiirbank und Charlot- tenburg 205,320 .. 249,948 Trappe 329,303 .. 393,223 The total amount paid in dividends by the Rhenish- Westphalian colliery companies in 1913 was 24,495,000 marks, distributed amongst the shareholders of 24 com- panies, whose capital value at the prices current on December 31, 1913, was 367,725,000 marks. This gives an average yield of 6’66 per cent., as compared with 5’23 per cent, in 1912, and 5’54 per cent, in 1911. Capital calls were made by seven companies, the total, 15,850,000 marks, comparing with 6,900,000 marks in 1912, and 8,723,000 marks in 1911. Epitomising the experience of the last five years, it is found that the Rhenish-Westphalian colliery companies have in that period distributed in dividends 109,415,000 marks, whilst calls to capital have been made amounting to 55,623,000 marks. Turning to the brown coal industry, it is stated that there has been little animation in recent years in the shares of companies engaged in this branch of business, the great part of the capital being privately held. Some excitement, however, was caused at the end of August by heavy buying at Berlin of lignite shares on behalf of Herr Petschek, a Bohemian mining magnate. Poplar Borough Council has extended its contract with Hinchliffe and Co., for the supply of Swadlincote slack for a further year at the reduced rate of 16s. 6d. per ton.