Knight, J. J., l/o Widnes; Gorton Brook Chemical Works, West Gorton, Manchester. Langdon, Dr. M. J., l/o Victoria Park; 3, Cooper Street, Manchester. Leather, Dr. J. Walter, lo Calcutta; Dehra Dun, N.W.P., India. Lombard, E., l/o Rue Grignan; 10, Rue Breteuil, Marseilles, France. Lord, F. J., 1/o Rochdale ; Brooklands, Millbrook, Stalybridge. Lowe, H. A., Journals to Halliwell Bleachworks, Smithills, near Bolton. Lye, W. T., 1/o The Firs; Braehead, Cromwell Road, Luton, Beds. McFarlane, W., 1/o Thornliebank; Holmeview, Mansefield, Pollokshaws, Glasgow. Marshall, Dr. T. R., 1/o Cardiff; 4, East Castle Road, Merchiston, Edinburgh. Mumford, A., l/o Westwell Street; 19, St. James' Place, Plymouth. Myers, W. S., 1/o Newark; 98, Easton Avenue, New Brunswick, N.J., U.S.A. Pomeroy, Dr. C. T., 1/o Halsey Street; (Office) cor. Passaic and Reynolds Avenue; and (Journals) 18, Pennington Street, Newark, N.J., U.S.A. Preston, E. S., 1/o Tenbury; 10, Holyrood Terrace, The Hoe, Plymouth. Rawson, C., l/o Technical School; 2, Melbourne Place, Bradford. Rayner, J. A. E., 1/o Wavertree; High Wray Bank, Ambleside. Richardson, C. T., 1/o Portman Mansions; 9, Rosetti Mansions, Cheyne Walk, Chelsea, S.W. Roberts, J. H. M., 1/o Brixton; Laboratory, 6, Trinity Square, Tower Hill, E.C. Saint, W. J., Journals to Kurfuerstenstrasse 5, BonnPoppelsdorf, Germany. Schweich, E., l/o Jamaica; 20, Avenue Road, Regent's Park, N.W. Smiles, Jas., 1/o Queen Street; Blandfield Chemical Works, Canonmills, Edinburgh. Smith, A. J., l/o Pitsmoor; Houghton Villas, 2, Andover Street, Sheffield. Stuart, Jas., Journals to 22, High Street, Hull. Taylor, G. W., 1/o Gamesley; Dinting Vale Printworks, Dinting, near Manchester. Taylor, Jas., 1/o Sheffield; Department of Mines, Sydney, N.S.W. Twitchell, E., l/o West 7th Street; 10, Bellevue Avenue, Mount Auburn, Cincinnati, Ohio, U.S.A. Wates, E. A., l/o India; 56, Breakspeares Road, St. John's, S.E. Webb, S. G., l/o Port Royal; 2314, East Grace Street, Richmond, Va., U.S.A. Weber, Dr. C. Otto, l/o Rectory Road; 2, Randolph Street, Crumpsall, Manchester. Wilson, A., l/o Stourbridge; Shrewsbury House, Stafford. THE artificial production of burning gases may be said to have commenced in the year 1669 by Becher, and in the last century the obtaining of burning gas from coal was evidently known to many. The practical application of this knowledge, however, appears to have taken place only in the beginning of the present century, when large gasworks were established in London by Mr. Winsor, to whose great energy we owe the establishment of coal-gas production. There is little doubt that the inventors of coal-gas, Mr. Winsor and Mr. Murdoch, possessed but a small knowledge of the chemistry of the gas they were producing. This is quite evident from the pamphlet published by Mr. Winsor in 1807 under the heading of "Plain Questions and Answers about Coal-Gas." There, in one of his replies, he asserted that there was not the slightest danger in taking a burning candle into a room filled with gas, as the gas could not ignite owing to its being mixed with air. Even up to the present day chemists have given little attention to the gasification of coal and liquid hydrocarbons, and it has been left to the engineer to devise improvements and to arrive at more economic working, but without changing the original method. Chemists have devoted themselves to the study of certain by-products of gas-making, but not to the chemistry of the material the engineer himself is treating, and the object of my lecture is to, if possible, indicate what a wide field for research exists in this direction. The immense knowledge we possess of the hydrocarbons contained in the by-products of coal gasification affords us a magnificent vantage ground from which to approach the study of the treatment of the original material from which these by-products come. I propose first to take the gasification of coal and see what are the results obtained by the present method, both as regards the gas produced and the composition of the by-products. I then propose to show what I have proved to be possible, both as regards the gas produced and the quantity and nature of the by-products, and compare the two. I will also deal with the gasification of liquid hydrocarbons as at present conducted, and show by what method it may be improved; and also what liquid hydrocarbons I think best suitable for gas production. I will divide the gas produced from coal under three heads (see previous page). According to the analysis of English coal-gas manufactured in London, made by Professor Foster in the year 1891, we see that the first-mentioned elements, A, are found in very small quantities compared with the bulk of the gas. The analysis of seven different samples is as follows: The first-mentioned series, viz., the illuminants or unsaturated hydrocarbons A, are represented by 4.35 to 7.88 per cent., while the second series (B), the gas carriers, range from 89 to 92 per cent., the balance being foul gases, say 4 to 14 per cent. Now, as regards the by-products obtained, they represent in quantity about 10 gallons per ton of coal gasified, and an analysis of these 10 gallons shows the contents to be as per Table IV. TABLE IV. The Production of Gas and By-Products from 1 Ton. None. Naphtha. 0'1 ....... Light gas-oil.......... 38 None. Anthracene.... 1.5 lb. Pitch......... 100 39 Lubricating oil ....... 10 galls. Such are the results of the present gasification of coal. It is known that nearly all kinds of coal contain from 50 to 70 per cent. of fixed carbon, and from 30 to 50 per cent. of volatile matter, and it is the latter which defines the goodness of coal for the purpose of gasification. How comes it, then, that by the analysis of Professor Foster referred to, the percentage of these hydrocarbons in coal The average quantity of volatile matters per ton of coal must be equal to 784 lb., but obtained in gas only 259 1 lb. That is, the average quantity in weight of volatile matter obtainable from a ton of coal (supposing we take 35 per cent. instead of 45 per cent., so as to allow of 10 per cent. for by-products and liquors) being 784 lb. ; the quantity actually obtained by the present method of gasification is only 302.2 lb. as gas, or a little over one-third, the rest being lost in the course of gasification. The correctness of the above calculation may be proved by taking the specific gravity of coal-gas, namely 0.4, which makes the weight of gas obtained per ton of coal equal to 292.8 lb. Both calculations give approximately the same result, and clearly show, as I have said, that only a little over onethird of the volatile matter contained in coal is gasified, the rest being lost or converted into solid substance. What is still more important, however, is that of this one-third only 42.2 lb. or about 5 per cent. of the whole consists of unsaturated hydrocarbons or illuminants. Now, the question arises, how are the two-thirds of the volatile matter in coal lost in the process of gasification? By numerous investigations it has been shown that illuminating gas is formed by the separation of hydrogen from saturated hydrocarbons. It has also been shown that the less the temperature at which coal is gasified, the greater is the quantity of unsaturated hydrocarbons in the gas obtained; that is, the gas obtained is less in quantity, but better in illuminating power. It is a known fact that gas taken for analysis from the retort at different times differs in its composition according to the time at which it is taken off. At the beginning it is considerably richer in illuminating power than at a later period. It is also noticed that as the process continues the quantity of unsaturated hydrocarbons decreases and the quantity of hydrogen increases. It is evident that this results entirely from the increased temperature under which the gas is produced. It is the same with petroleum. The composition of petroleum gas varies according to the temperature at which petroleum is decomposed. The gas obtained at a lower temperature contains considerably more carbon than hydrogen, while in raising the temperature the proportion of carbon diminishes and the hydrogen increases, and at a very high temperature pure hydrogen is obtained. This fact shows conclusively that the quantity of light-giving gases depends directly upon two factors. 1st. The quantity of the compounds which under a certain temperature will break up and give light-yielding elements; gasification is carried on at a high temperature, and the formed hydrocarbons, passing through the highly-heated mass, throw off the hydrogen in such large quantities that this gas forms nearly 50 per cent. of the whole of the gas produced. In addition to this a quantity of hydrogen produced from the broken up bydrocarbons is consumed by the oxygen in the coal, and a further quantity goes with the nitrogen to form ammonia. That such is the case can be seen from even a superficial survey of the elements of the gas made. We see hydrogen combined with carbons in the unsaturated form amounts to only 6 lb., and in the form of marsh gases 36.9 lb., while in the pure form it amounts to 22.5 lb. ; and when it is borne in mind that there exists no free hydrogen in coal, it will be seen to what a great length the breaking up of the hydrocarbons has gone. In other words, the temperature of the retort has been raised to such a point as to destroy nearly the whole of the unsaturated hydrocarbons. It will be seen from the foregoing that the gasification of coal must be carried on at a lower temperature, the result of which will be the unsaturated hydrocarbons will be preserved, a maximum candle power obtained, and at the same time a large quantity of the hydrocarbons of the benzene series obtained. Before explaining what I have, by experiment, proved to be possible, and I believe practicable, I may say that, in the treatment of coal for gasification, I have assumed that coal is a substance which may be roughly described for my purpose as fixed carbon saturated with hydrocarbons, and that these hydrocarbons for the most part belong to the paraffin series. Instead of passing direct to the discussion of what I suggest as the proper method of coal gasification, I will first make a few remarks upon the gasification of liquid hydrocarbons, seeing that it is from this starting-point I have approached the subject of the gasification of coal. In the year 1824 Mr. P. Taylor patented an apparatus for gasifying liquid hydrocarbons. His invention is The This is the first apparatus for oil-gas making that I have been able to find. From the drawing it will be seen that his apparatus consists of one or two retorts, in the centre of each of which is placed a pipe reaching to the bottom. The retort is filled with coke or other incandescent material. fluid enters the pipe and descends to the bottom of the retort, afterwards passing in a gasified form through the incandescent material in the retort and escaping at the top. Shale oil was used for the purpose. The main principle of passing gas through an intensely heated surface has been adopted by all the patentees of oilgas apparatus from P. Taylor in 1824 up to the present day. The second idea of all these oil-gas manufacturers was to try to gasify the whole of the oil treated, without leaving any residues; the consequence has been they have all more or less failed. Little attention has been paid to the few, but still serious, attempts that have been made in the scientific world to obtain valuable bye-products in the gasification of oil. In 1877, Lietny, Professor of the Technological Institute of St. Petersburg, patented and published in the Transactions of the Berlin Chemical Society a process for obtaining aromatic hydrocarbons from Russian petroleum oils, and to him certainly belongs the first rational gasification of oils. His method has been improved upon by Dr. Smith at Mr. Ragosine's works near Nijni Novgorod, and, thanks to the enterprise of Mr. Ragosine, we have been able to utilise naphtha for the production of gas of high illuminating power, and at the same time a large quantity of very useful and valuable by-products. The main attention at these works has been directed to the utilisation of those mineral oil products obtained by the distillation of Russian crude oil which could not be used in oil-lamps on account of their heavy specific gravity, and which at the same time were too light to be used as lubricants. These products of Baku crude oil comprise nearly 20 per cent. of the oil. It was therefore very important for Mr. Ragosine, having his works in the centre of Russia, far away from the sources of naphtha, to have no useless waste; and the attention of all chemists and scientific men engaged by him (and among them I may mention the names of Professor Schutzenberger, of Paris, and Professors Markovnikoff and Ogloblin, of Moscow) has been directed to discovering the best methods for the utilisation of the whole of the Russian oils. Now, although the gasification of oil as conducted at the Ragosine factory is carried on mainly with the view to obtaining the bye-products which are so valuable, and which amount to 40 per cent. of the oil treated, yet even under such conditions they obtain about the same quantity and quality of gas per gallon of oil used as, according to the latest published information, has been obtained in England, where, or indeed anywhere else except Russia, no valuable by-products whatever are obtained. Of course this may partly be attributed to the fact that in Western Europe, as well as in America, where the gas industry is so widely developed, the attention of the investigators and inventors has been directed to naphtha products and other oils only from the point of view of how to obtain the largest quantity of gas possible; while in Russia, where the gas industry is in its infancy, the chemists have spent their energies on by-products, regarding the gas question as a secondary one. Therefore both the Russian chemists and foreign gas engineers have been equally wasteful, the first wasting the gas, and the latter wasting the byproducts. For my experiments upon liquid hydrocarbons I have taken three different distillates, namely, (a) solar distillates of the specific gravity of 0.8625; (b) solar distillates of the specific gravity of 0.8853; (c) a specially prepared distillate of the specific gravity of 0.899. As shown by Table V., by distiliation of sample (a) at temperatures ranging from 0° to 350° Celsius, I obtained 67 per cent. of a product of the specific gravity of 0.8442, By distillation of sample (b) at the same temperatures I obtained none at all. By distillation of sample (c) I obtained at the same temperatures 28 per cent. of a distillate of the specific gravity of 0.8607. I subjected these three different kinds of distillates to the process of gasification. The apparatus used for that purpose consisted of two iron pipes laid horizontally one above the other, and connected together at one end. The other end of the upper pipe is carried up vertically about 8 in.; into the top is inserted a glass funnel with a stopcock. The other end of the lower horizontal pipe is connected with a condenser for collecting the byeproducts, which in its turn is connected with a gasholder for receiving the gas obtained. The difference between the results obtained by gasifying at a high temperature and at a low temperature can be clearly seen by Table VI., Example A. You will observe that the illuminating power of the gas produced at a temperature of 1600° F. is much less than that of the gas produced at a temperature of 1300° F. If a still higher temperature be used, the gas produced is again of a lower illuminating power. The next thing we observe is, that in gasifying the three samples of oil described in Table V., a, b, and c, at the same temperature, we obtain very different results, and the best result is obtained from sample c, both as regards quantity and quality of gas, and of by-products. The lightest sample certainly produced a foot or two more of gas per gallon, but the candles are only 665, as compared with 823 in the case of sample c. Then, again, the percentage of byproducts in the case of sample a is 37 5 of a gravity of 0.9266, while in the case of sample c it is 38 per cent. of the gravity of 0.967. The difference so far as quantity is concerned is very slight, but in the value of the by-product it is very great. The analysis of the by-product in the case of sample a clearly shows that it contains a large quantity of light spirit, mixed with the benzol, which mixture it has proved impossible to separate by fractional distillation, owing to the boiling points of the two being so nearly approximate. The presence of these spirits in benzol is only ascertained by gravity and not by the boilingpoint, benzol mixed with spirit having a much lower gravity than pure benzol. On the other hand, the analysis of the by-product obtained from sample c, as seen in Table VI., shows that it mainly consists of pure benzol with very little light spirit. As I have explained before, the most important part in the process of the gasification of the volatile matter in coal is to break up the saturated hydrocarbons into unsaturated hydrocarbons, which are the illuminating elements. It seems to me that, beginning with the first invention of coal gasification up to the present time, the method used, which results in obtaining only 42.2 lb. of unsaturated hydrocarbons out of 784 lb. of volatile matter, cannot stand scientific or practical criticism. Guided by the results of experiments in oil gasification, and having come to the conclusion that liquid hydrocarbons exist in coal, I thought of gasifying coal on the same principles as oil, in order to avoid the destruction of the volatile matters which, as has been shown, is brought about by the present methods; but I have been prevented at the outset by the absence of any means of carrying out this purpose, and therefore I decided to adopt a combination process of distillation and gasification in the presence of an inert gas, for the purpose of mechanically taking off, or rather squeezing out, those hydrocarbons, which, as stated before, I had concluded existed in coal in liquid form. The inert gas found by me the most suitable for this purpose appeared to be pure hydrogen or a mixture of hydrogen and carbonic oxide. I have also used pure nitrogen, but I found that the breaking up of the oils went |