remarkably rapid, and the present depression is exceptionally acute. Mr. Head gives some well-considered hints for relieving this depression. He does not, however, indicate two directions in which the South Russian ironmaster might possibly turn his attention with advantage. Russia produces more manganese ore and more petroleum than any other country in the world. Would it not be possible to utilise more extensively these valuable products on the spot, by developing the manufacture of spiegeleisen and ferromanganese, and by increasing the employment of petroleum for metallurgical purposes? Remarkable as the figures given by the author showing the comparative 'production of pig iron in 1899 are, they are less striking than later statistics. In 1901, when Russia produced 2,831,000 tons of pig iron, the United States produced 15,878,354 tons, the United Kingdom 7,928,647 tons, and Germany 7,860,893 tons. Similarly, the latest South Russian statistics show more clearly than the figures given by the author the present plight of the iron and coal industries. The report presented at the meeting of ironmasters at Kharkoff last month gives particulars of the South Russian production during the year ended on September 1st, 1902. During that period the Donetz coalfield yielded 9'4 per cent. less than the production of the previous year, a diminution unprecedented in the history of the coalfield. The production of coke showed a decrease of 11.3 per cent., and the production of pig iron a decrease of 2-75 per cent. On September 1st, 1902, of the 56 blast furnaces in South Russia, only 23 were in operation. The output of iron ore was, in conseqence of the crisis in the iron trade, notably reduced. Only 48 of the 79 mines at Krivoi Rog were at work. A comparison between the possible productivity of the district and the production during the year, affords a clear indication of the depression. collieries furnished only 59 per cent. of their possible output, the coke ovens 42 per cent., the blast furnaces 55 per cent., and the Krivoi Rog mines 37 per cent. The : Mr. W. H. HERDSMAN (Messrs. Edward Riley and Co.) writes to Professor Le Neve Foster, F.R.S. :At the Society of Arts' meeting last week, I listened to Mr. Head's very interesting paper, and also to your remarks on the same, but had to leave before the conclusion of the discussion. Having myself visited, last summer, the several districts in question, I think Mr. Head's description of the ore bodies as "boat-shaped" is calculated to convey a better mental idea of their real character than is the word "lenticular." I agree, however, with you that the Kertch iron ore deposits are in all probability much larger, and likely to prove of greater importance, than those of Krivoi Rog. Apparently Mr. Head had not visited them, or he would not say they are not important. The friability of the Donetz coal is no doubt a natural quality, quite independent of the weather, and Mr. Head's explanation of the cause seems to me to be a very feasible one. My recent three months' tour in Russia also included a visit to the Caucasian manganese deposits at Tchiatouri, for the purpose of comparing them with the Brazilian deposits, all ot which are personally known to me. I am in full agreement with yourself and Mr. Head as to the cordiality with which Englishmen are received in Russia, and regret the imperfect understanding which exists in England respecting that country and its people. MEETINGS OF THE SOCIETY. Wednesday evenings, at Eight o'clock :JANUARY 14.-"Industrial Trusts." BY PROF. W. SMART, LL.D. SIR ROBert Giffen, K.C.B., LL.D., F.R.S., will preside. JANUARY 21.-"The Metric System." By A. SONNENSCHEIN. ALEXANDER SIEMENS will preside. JANUARY 28.-"The Cost of Municipal Trading." By DIXON H. DAVIES. The LORD CHIEF JUSTICE, G.C.M.G., will preside. 4.-" FEBRUARY "Methods of Mosaic Construction." By W. L. H. HAMILTON. FEBRUARY 11.-" The Port of London." By Dr. B. W. GINSBURG. FEBRUARY 18. "Three-Colour Printing." By HARVEY DALZIEL. CARMICHAEL THOMAS will preside. Dates to be hereafter announced :- "Existing Laws, By-laws, and Regulations relating to Protection from Fire, with Criticisms and Suggestions." By T. BRICE PHILLIPS. (Fothergill Prize Essay.) "Oil Lighting by Incandescence." By ARTHUR KITSON. "The Use of Electrical Energy in Workshops and Factories." By ALFRED C. EBORALL, M.I.E.E. "Modern Bee-Keeping." By WALTER FRANCIS REID, F.C.S. "Tonkin, Yunnan and Burma." By FRED. W. CAREY, late H.B.M.'s Acting-Consul at Szemao, China. "Education in Holland." By J. C. MEDD. 66 Monday Evenings, at Eight o'clock:JULIUS HÜBNER, 'Paper Manufacture." Four Lectures. LECTURE I. FEBRUARY 2.-History-CelluloseRaw materials-Boiling, washing, breaking, and bleaching of rags-Esparto-Straw. LECTURE II. FEBRUARY 9.-Soda recovery— Manila hemp-Jute and other raw materials-Mechanical wood-Wood cellulose-Beating-SizingLoading-Colouring. LECTURE IH.-FEBRUARY 16.-Stuff-chestRegulator Sand-tables Strainer Hand-made paper-Fourdrinier paper machine. LECTURE IV. FEBRUARY 23.-Single cylinder and other types of paper-making machines- Finishing -Cutting-Statistics-Paper-testing-Experimental Surveyors, 12, Great George-street, S. W., 8 pm. Mr. H. T. Scoble, "Rural Drainage and Sewage Disposal." Geographical, University of London, Burlington. gardens, W., 8 p.m. Camera Club, Charing-cross-rd., W.C., 8 p.m. Dr. Studies in the TUESDAY, JAN. 13... Royal Institution, Albemarle-street, W., 3 p.m. Professor A. Macfayden, "The Physiology of Digestion." (Lecture I.) Medical and Chirurgical, 20, Hanover-square, W. Civil Engineers, 25, Great George-street, S.W., WEDNESDAY, JAN. 14...SOCIETY OF ARTS, John-street, Adelphi, W.C., 8 p.m. Prof. W. Smart, "Industrial Trusts." Japan Society, 20, Hanover-square, S.W., 8 p.m. Royal Literary Fund, 7, "Adelphi- terrace, W.C., 3 p.m. Archæological Association, 32, Sackville-street, W., Biblical Archæology, 37, Great Russell-street, THURSDAY, JAN. 15...Antiquaries, Burlington-house, W., ε p.m. Linnean, Burlington-house, W., 8 p m. London Institution, Finsbury-circus, E.C., 6 pm. Rev. W. Marshall, "The Romance of Architecture." Royal Institution, Albemarle-street, W., 3 p.m. Dr. Mining and Metallurgy, at the Rooms of the 2. Historical, Clifford's-inn, Fleet-street, E.C., 5 p.m. Numismatic, 22, Albemarle-street, W., 7 p,m. Optical, 22, Hanover-square, W., 8 p.m. FRIDAY, JAN. 16...Royal Institution, Albemarle-street, W., 8 p.m. Weekly Meeting, 9 p.m. Prof. Dewar, "Low Temperature Investigations." Civil Engineers, 25, Great George-street, S.W.. 8 p.m. (Students' Meeting.) Prof. W. C. Unwin, "The Measurement of Water." Mechanical Engineers, Storey's-gate, S.W., 8 p.m. Mr. H. F. Donaldson, "Cutting Angles of Tools for Metal Work as Affecting Speed and Feed." Quekett Microscopical Club, 20, Hanover-square, W.C., 8 p.m. SATURDAY, JAN. 17...Royal Institution, Albemarle-street, W., 3 p.m. Sir Frederick Bridge, "The BiCentenary of Samuel Pepys: His Musical Contemporaries, Criticisms, and Compositions." (Lecture I.) Journal of the Society of Arts, Proceedings of the Society. CANTOR LECTURES. "THE FUTURE OF COAL GAS AND ALLIED ILLUMINANTS." BY PROFESSOR VIVIAN B. LEWES, Royal Naval College, Greenwich. pre Lecture IV.-Delivered December 15th, 1902. The title of "Allied Illuminants supposes a closer relationship than the mere fact that different substances are utilised for the production of light, and certainly no bond of alliance could be closer than that which exists between coal gas and oil as illuminants. Born and bred in the same cradle, they have walked hand in hand ever since, as it was whilst Lord Dundonald was first distilling coal in order to obtain coal naphtha from it that he also made coal gas, and although at that period interest in the liquid illuminant caused its gaseous brother to be overlooked, the work of Murdoch and the puffing of Winsor put coal gas into a position which caused it to outshine the liquid twin. In treating of oil lighting, as existing in the immediate past, and as destined to play an important part in the future, it is clear that the animal and vegetable oils, which were much in evidence in illuminating the dark ages, and forming a twilight to the brilliant illumination of the past century, may be disregarded; so that, considering only mineral oils, the relationship existing between coal gas lighting and oil lighting is the closest that one can conceive. If certain classes of coal be distilled at a comparatively low temperature, we obtain oil, and if other classes are distilled at a high temperature we obtain coal gas. For the past twelve years oil gas has played so important a part in the carburetting of coal gas that the relationship between them becomes still more inseparable. In some parts of the world nature in her prodigality supplies natural gas, and even in this country some is to be found, for there are not wanting those who look forward to Sussex becoming a Pennsylvania on a small scale. However, natural gas is small in quantity as compared with the natural sources of mineral oil, and this gives the latter illuminant a distinct advantage. The advent of the coal gas industry in the early twenties provided tar from which light oils could be obtained by distillation, and the consumption of these in the Read-Holliday lamp has ever since been a favourite source of light for the coster and the travelling showman. In this lamp the principles which underly many of our most modern developments for burning oil for heating and lighting are to be found, as it is a wickless lamp which gasifies the coal tar naphtha that yields the flame, the flame itself providing the necessary heat to keep the supply of gas constant. Other lamps of the same type are also made for the consumption of oils of higher flash point, but although of great utility in illuminating open spaces, the danger of a leakage of burning oil and the slight irregularity in the supply of oil to the vapourising chamber render them unfit for use in buildings containing inflammable materials. The Read-Holliday lamp was practically the only mineral oil lamp existing up to the middle of the last century, and 1850 marks the birth of the great mineral oil industry. In 1847, James Young, whose name is as indelibly connected with mineral oil lighting as is that of Murdoch with ccal gas, discovered, or had pointed out to him, a leakage of oil from a seam in the Riddings Colliery at Alfreton. Collecting this, he succeeded in preparing from it by distillation a valuable lubricant; but the demand for it very soon exceeded the supply that he could obtain, and in his attempts to keep pace with the trade he had created, he found that the same oil could be obtained by the distillation of certain grades of shale. Hence arose the Scottish oil industry. The purpose for which the oil was obtained was at first purely that of lubrication, and the light oils distilled off from the heavier ones which were fitted for this purpose were practically a waste product. Although some attempts were made to utilise the lighter distillates for burning in a lamp, no practical results were obtained until 1853, when it was noticed that this oil was being bought at a very cheap rate, and was being exported to Hamburg. Curiosity being aroused, it was found that the oil was being used in Germany in lamps made by Stohwasser, of Berlin. This led to the introduction of these lamps into England, where they were afterwards manufactured, with improvements, by Messrs. Laidelaw, in Edinburgh. It was in 1859 that commercial circles in America were convulsed by the fever of specu lation roused by Colonel Drake succeeding in obtaining petroleum by boring in districts where previously it had merely occurred as a scum on the surface of stagnant water, and the next year or two resulted in the flooding of the market with oil at prices never before deemed possible. This led to the introduction of lamps from Germany for its consumption, but American ingenuity soon led to many improvements, and from 1859 to 1879, something like 1,600 patents were taken out for lamps fitted for the consumption of oil. Nor was America alone in its efforts to improve the methods for the consumption of mineral oil. Some of the most distinct advances in this direction were made in England by such workers as Messrs. Hincks, Silber, and Defries, with the result that we have to-day lamps for the consumption of oil that develop from it an amount of light undreamt of in the early days of the oil industry, whilst the advances in the manufacture of the oil lamp have been accompanied by the discovery of oil deposits in every part of the world. As the oil leaves the well it is a mixture of many hydrocarbons, mineral oils even varying amongst themselves in the class of hydrocarbons which are present in them. The crude oil has then to be subjected to a rough fractional distillation, which yields first of all such easily volatilised products as petroleum spirit and the low flash point oils, whilst those distillates that have a flash point of over 73° Fahr., and yet are of sufficient mobility to be fed with regularity by the capil larity of the wick to the flame, come under the heading of lamp oil, and are utilised in the ordinary mineral oil lamp. In the burning of such oil it is drawn up by the wick from the lamp reservoir into the zone of heat created by the combustion, and is there converted into a gaseous mixture of hydrogen and hydrocarbons which yield the flame, whilst the actions going on within the flame yield the light which is emitted before the complete conversion by combustion of the flame gases into carbon dioxide and water vapour, the ultimate products of complete combustion. In order to secure the best results with the combustion of oil in a lamp, it is necessary to devote special care to several factors, so that the lamp shall burn with a smokeless flame of as high illuminating power as possible, and emit only the products of complete combustion. One of the most important points is the wick, by which the oil is fed to the flame, and the amount of oil so supplied must be carefully regulated, as if the oil be in excess the air supplied to the flame is unable to burn it completely, with the result that the lamp smokes and products of incomplete combustion are formed, whilst if the flame be starved, the loss of light is very great. The quality of the wick, moreover, demands careful attention, and it should be woven loosely from a coarse thread made of long staple cotton, and with as little twist as possible. The wick before use must be well dried, and when in position in the lamp must just fill the wick holder without being compressed, and should be of sufficient length to reach to the bottom of the oil reservoir and leave an inch or two on the bottom. If the oil reservoir be not too deep, a wick of the above character will feed the oil to the flame in a uniform manner, but as all the oil passes through the wick, it is evident that any solid impurities in the oil will be filtered out and choke the capillaries upon which the action of the wick depends, so that after a time the choked wick must be thrown away and a new one inserted, this being done when an inch or two of wick has been burnt away. During the first few moments after lighting the lamp the oil burns with a heavy smoky flame, on account of its being unable to get the necessary oxygen for its complete combustion; and soot, together with other injurious and malodorous products of incomplete combustion, escape into the air. To remedy this an artificial current of air has to be created, which shall supply the requisite amount of oxygen to complete the combustion, at the same time giving rigidity to the flame, and by ensuring the combustion taking place in a shorter space of time and so increasing the calorific intensity, raising the carbon particles. to a high degree of incandescence. This can be done in two ways, first by the aid of a chimney by means of which the heated products of combustion draw in the air at the base of the flame, and secondly, by creating a draught from a small clockwork fan in the base of the lamp. The direct impact of this current of air, however, would cause the flame to be very unsteady, so that its uprush is checked by placing in its path perforated screens of metal and similar contrivances, by which an even supply of air is ensured which is deflected where required on to the flame by suitable metal discs and cones. The economic advantages claimed for the oil lamp are, of course, based upon the amount of light that can be developed by the combustion of the oil. The most generally accepted estimate of this important factor is that given by Dr. Boverton Redwood, who states that the oil consumption with duplex burners giving a duty of about 28 candles, averaging 50 grains per candle per hour, whilst with argand burners with a duty of 38 candles, it is about 45 grains per candle per hour. It must be remembered, however, that although these are reliable results for the best types of lamp, the figures by no means represent the duty obtained by the ordinary consumer in daily practice from all types of lamp. The results obtained from a selection of the lamps in use to-day are shown in the following Table: It will be noticed from this that with the flat flame lamps of the type first introduced the American and Russian oil give practically the same result, whilst with the circular wick lamps the American oil appears to have a great advantage over the Russian. After prolonged burning, however, this difference is considerably lessened, and the same sort of results are to be found in the consumption of American and Russian oil in heating stoves. Very little attention has been given to the amount of heat emitted by our illuminants, whereas it places a distinct limit upon the size and illuminating power of oil lamps, for |