Size to produce 2 gallons per hour, £3 15s. Pamphlets on application. BROWN & SON, Engineers, Coppersmiths, and Joiners, MURIEL STREET, & CHARLOTTE STREET, LONDON, N. BRADY & & MARTIN, LTD., £5 5s. To be obtained of all Opticians, or the SOLE MAKERS: NATURE says: "Teachers requiring efficient apparatus at a low F. DARTON & CO., OPTICAL WORKS, cost for lecture or laboratory purposes, might consult the list with advantage." List on application by mentioning NATURE. ALUMINIUM RECTIFIERS. FREDK. JACKSON & Co. Patent No. 18013. For charging any class of accumulators, driving small motors, &c., direct from alternating mains. Works on any periodicity or voltage; (Late MOTTERSHEAD & CO.), 14 CROSS STREET, MANCHESTER. Goods Entrance: 10 Half-Moon Street. action absolutely infallible: LABORATORY FURNISHERS. по moving parts; high efficiency; requires no atten tion. Made (by agreement with the Nodon Valve) in four sizes to charge from 1 amp. to 10 amps. Prices from £3 3s. to £8 8s. THE ELECTRICAL COMPANY, Ltd., 121-125 Charing Cross Road, Telegraphic Address-"APPARATUS, MANCHESTER. MACMILLAN & & CO.'S CO.'S LIST. THE LIFE & EXPERIENCES OF Sir Henry Roscoe, D.C.L., LL.D., F.R.S. Written by Himself. With Photogravure Portraits and other Illustrations. 8vo. 12s. net. A SYSTEM OF APPLIED OPTICS. BEING A COMPLETE SYSTEM OF FORMULE OF THE SECOND ORDER, AND THE FOUNDATION OF A COMPLETE SYSTEM OF THE THIRD ORDER, WITH EXAMPLES OF THEIR PRACTICAL APPLICATION. By H. DENNIS TAYLOR, Optical Manager to T. Cooke and Sons, Ltd., of London, York, and Cape Town. 4to. NEW WORK ON ASTRONOMY BY SIMON NEWCOMB. A COMPENDIUM OF SPHERICAL ASTRONOMY. 30s. net With its Applications to the Deter mination and Reduction of Positions of the Fixed Stars. By SIMON NEWCOMB. 8vo. 12s. 6d. net. AN INTRODUCTION TO ASTRONOMY. Illustrated. Crown 8vo. 55. net. SCHOOL WORLD.—" It contains a clear and accurate account of the present position of astronomical science, and should appeal to students who do not wish merely to be entertained or amazed with diffuse descriptions of wonders and marvels of the heavens, but prefer to digest precise statements of principles, methods, and results." PRACTICAL EXERCISES IN CHEMISTRY. By G. C. DONINGTON, M.A., Grammar School. Globe 8vo. 2s. 6d. Senior Science Master of Leeds *** All the subjects included in the new syllabus in Chemistry for the Matriculation Examination of the University of London are dealt with in thi sbook. THE ANNUAL OF THE BRITISH SCHOOL AT ATHENS. No. XI. Session 1904-5. Crown 4to. 21s. net. The Contents include:-The Palace of Knossos and its Dependencies: Provisional Report for 1905. By A. J. EVANS. — Honorary Statues in Ancient Greece. By M. K. WELSH.-Boundary and Mortgage Stones. By H. J. W. TILLYARD.-A Visit to Skyros. By R. M. DAWKINS.-Laconia: Excavations at Angelona, Geraki, Thalamae, &c. By A. J. B. WACE and F. W. HASLUCK.-A Votive Relief to Asclepius. By G. P. BYZANTINOS.-An Apollo Inscription from Delium. By Prof. RONALD BURROWS. - Palaikastro: Excavations in 1905. By R. M. DAWKINS, R. C. BOSANQUET, and C. H. HAWES.-Cretan Palaces and Aegean Civilisation. By D. MACKENZIE, &c. For the New Syllabus of the Preliminary Examination for the Certificate (1907). LESSONS IN SCIENCE. A Preliminary Course of Physics and Chemistry. By Professor R. A. JUST PUBLISHED. A SCHOOL GEOMETRY. Parts I and II, with an Introductory Course of Experimental and Practica) Work. Part I. Lines and Angles, Rectilineal Figures. Part II. Areas of Rectilineal Figures. By H. S. HALL, M.A., and F. H. STEVENS, M.A. Crown 8vo. A MANUAL OF GEOMETRY. 2s. 6d. By W. D. EGGAR, M.A., Assistant Master at Eton College. An experimental treatment of Geometry, in which Theorems are taken along with the practical work. NATURE.--"We know of no text-book of elementary geometry which can be more confidently recommended to teachers, and none from which students are likely to derive more profit." KEY JUST PUBLISHED. AN INTRODUCTION TO PRACTICAL GEOGRAPHY. By A. T. SIMMONS, B.Sc., and H. RICHARDSON, M.A. 35. 6d. KEY, 3s. 6d. FROM THE COTTON FIELD TO THE COTTON MILL. Transition in North Carolina. By HOLLAND THOMPSON. Crown 8vo. 6s. 6d. net. Study the Industrial INVAR The parented Alloy of Nickel Steel which has the smallest known Coefficient of Expansion. Rods, Tapes, Wire, &c. Invar Compensation Pendulums in three grades. The calculations are made by a distinguished Mathematician on the basis of measurements made at the National Physical Laboratory. Regulator Clocks for Laboratories and Observatories fitted with Invar Pendulums. The highest grades fitted with contacts at moderate prices. Invar Tapes for Base Lane Measurements divided to the utmost accuracy and Standardised at the National Physical Laboratory. Standard Meters, &c., &c. J. H. AGAR BAUGH, 92 Hatton Garden, London, E.C. Telephone No. 4722 Holbern Telegraphic Address: "Voider, London." Moderate Rates. Absolute Security. LOSSES PAID OVER £28,000,000. THE IRISH NATURALIST. A Monthly Magazine of Irish Zoology, Botany, and Edited by GEO. H. CARPENTER, B.Sc., and R. LLOYD Annual Subscription, 5s. Post Free to any Address. 56 CHARING DENT'S ASTRONOMICAL CLOCKS, SIDERFAL OR MEAN TIME CLOCKS FOR OBSERVATORIES, £21 & UPWARDS. Nature says: "MESSRS. E. DENT & Co. have lately introduced a new astronomical clock which should find its way into many observatories where an accurate instrument is required at a moderate cost. For the sum of £21 they supply a clock with a 10-inch dial, dead-beat escapement, and wooden rod seconds pendulum in a solid mahogany case; and after examining the instrument we have no hesitation in pronouncing it a marvel of cheapness." E. DENT & CO., Ltd., Watch, Clock, and Chronometer Makers By Special Appointment to H.M. the King. Makers of the Great Westminster Clock, Big Ben. Makers of the Standard Clock of the Royal Observa tory, Greenwich, and the Principal Observatories throughout the World. Only Addresses 61 STRAND, TRADE MARK DENT PROTECTION from MOSQUITOES ARMBRECHT'S PYRETHRUM. 2s. 9d. a Bottle post free inland; Ss. 9d. to all parts of the World. HARVEY & PEAK, BY APPOINTMENT TO THE ROYAL INSTITU- POST OFFICE BRIDGE SETS AND CROSS ROAD, LONDON, w.c. SCIENTIFIC WORTHIES. The following is a list of the Steel Portraits that have appeared in the above Series:- N.B.-The Portraits of Sir A. Geikie, Lord JAMES PRESCOTT JOULE. JAMES JOSEPH SYLVESTER. DELEEFF. LOUIS PASTEUR. SIR ARCHIBALD GEIKIE. Lister. Prof. Cannizzaro, Prof. von Kölliker, Prof. S. Newcomb, Sir W. Huggins, Lord Rayleigh and Prof. Suess belong to a New Series and are Photogravures. Proof impressions of these, printed on Irdia paper, may be had from the Publishers, price 5s. each; or the Series of 35 Portraits in a Handsome Portfolio for £9, carriage paid. The Portfolio may be had separately, price 6s. Cheques and Money Orders payable to MACMILLAN & CO., Limited. THE NEW "STUDENT'S" STANDARD BAROMETER. (Registered Design No. 420,297.) This Instrument has been designed to meet the requirements of Students and others who find the need of a Barometer which will give exact readings, and cost but a moderate sum. It appeals especially to Colleges and Schools for Demonstration purposes. The construction is on that of the well-known" Fortin" principle. The level of the cistern mercury is reducible to zero, in exactly the same manner as in the more expensive forms. The diameter of the mercurial column is 25 inch, and affords a bold, well defined reading. The scales, by means of the double vernier, are capable of being read to or inch and 1 mi limetre. It is mounted on a well. polished, solid mahogany board, with plates for attachment to wall, opal glass reflectors for reading off, and screws for vertical adjustment. The metal portions are all well bronzed and lacquered, and the scales are silvered brass. We confidently recommend this Instrument for use as a "Standard" in Colleges and Schools, private Observatories, and by Gas and other Engineers. Price, complete, mounted as illustrated, £3 7 6, or may be had with one scale (either inches or millimetres), and with thermometer on other scale, at samme price. NATURE says:-" Provides an accurate instru ment at a moderate cost. FULL SIZE STANDARD BAROMETER of same design, bore o'5" diameter, inches and millimeter scales, verniers reading to o'002 inch and o'r m/m, on plished mahogany board with brackets and opal glass reflectors, £7 10 0 Sole Manufacturers and Proprietors of the Regd. Design: PASTORELLI & RAPKIN, Ltd., 46 HATTON GARDEN, LONDON, E.C. ACTUAL MAKERS OF ALL KINDS OF METEOROLOCICAL INSTRUMENTS. Contractors to H. M. Government. Estd. 10 years. Telegrams: Rapkin, Loudon." Nat. Tel. : 1981 Holborn. ILLUSTRATED PRICE LIST POST FREE. N.B.-If any difficulty in securing our instruments through your Dealer kindly communicate with us. 1/roth scale THE IMPROVED JOHN J. GRIFFIN & SONS, Ltd., HEIGHT RECORDER, KINGSWAY, LONDON, W.C., For Alpinists, Automobilists, Aeronauts, Cyclists, Tourists, &c. 2500 The Instruments will be found very handy for measuring heights and depths of every description; they are made in 13-in. and 24-in. sizes, in gilt, bronze, or silver, with a revolving altitude scale to register 2,500 feet up and 2,500 feet down, reading to 20, 50 and 100 feet. The zero point is 30-in., being the upright of the dial, and by setting o zero on scale to coin cide with the upright 30-in., the Instrument can be set according to the standard of Barometer and reduced to feet, the Instrument being of a regular scale of altitude, which can be used as a revolving scale accurately, the zero o being set to any point where the Recorder may be standing. 1-in. Gilt or Bronze Height Recorder as described, complete in snap morocco case, with table of altitudes, £1 13 0 THE SPECIAL MOTOR ANEROID. -in. Aneroid Barometer with 24-in. silvered dial, revolving scale, 2,000 feet up, 2,000 feet down, ascent scale in black, descent scale in red, in nickel or bronze flange case with screw holes for attaching; weight to uzs. £1 18 0 NEWTON & CO., 3 FLEET STREET, LONDON. THURSDAY, AUGUST 2, 1906. THE RAND THROUGH FRENCH SPECTACLES. Étude sur l'État actuel des Mines du Transvaal. Les Gites-leur Valeur. Étude industrielle et financière. By George Moreau. Pp. iv+218. (Paris: Librairie polytechnique, Ch. Béranger, Editeur, 1906.) THI HIS, the latest description of the Witwatersrand, is a curious medley of history, physiography, geology, mining, and finance, in which the author endeavours, and not without success, to picture to his readers the present condition of the gold-mining industry. The geological portion of the book consists of a résumé, fairly accurate and complete, of recent publications of the Geological Society of South Africa, while the mining and economic statistics are derived chiefly from the excellent compilations of the Witwatersrand Chamber of Mines and the Government Mines Department of the Transvaal. The description of the methods employed in the exploitation of the mines, and of the processes in vogue for the recovery of the gold from the ore during its progress from the rock-crushers, through the stamp-mill and the cyanide works, to the residue dumps, is well done and up to date, such recent innovations on the Rand as tube-mills and filter-presses being described. The use of the old chemical symbols (in which water is represented by HO) in giving the reactions of the cyanide process seems a strange reversion to the past. The author's reason for this procedure is found in a footnote on p. 165. It runs :- "Nous avons hésité pour choisir les notations des formules chimiques et avons fini par adopter les vieilles formules des équivalents. Les nouvelles vues relatives à la constitution des corps ont provoqué bien des attaques contre les théories dites atomiques et beaucoup de bons esprits regardent cette notation comme insuffisante. Nous ne prenons nullement position dans le débat et choisissons simplement les formules pondérales comme commode pour les praticiens." A curious commentary on the chemistry of the day! Not the least interesting part of the book is that which contains the author's views on the labour supply for the mines-the burning question of the hour in the Transvaal. Speaking of Kafir labour, he says, "whereas among the white working classes continuous work is necessitated by the fact that a day's pay scarcely suffices to meet a day's requirements, the Kafir has no wants (his food and lodging being found), and he works only for six or eight months, during which time he accumulates sufficient capital to enable him to return to his kraal, where he invests his savings in women and cattle. The work of his wives then provides the wherewithal for an idle life. Formerly, war furnished forth slaves for the conquerors; now the males consent to a little temporary fatigue in order to assure a life of complete tranquillity and repose. The constant succession of fresh hands, inexperienced in mine work, depresses the standard of efficiency for Kafir labour. The best workers are, of course, the few who spend their earnings (unfortunately largely in the consumption of alcohol), and consequently remain on the mining field." The author calculates that in the territories in which recruiting for native labour is permitted a supply of not more than 250,000 can be reckoned on. The labour requirements of South Africa (for mines, agriculture, and public works) amount at present to 380,000, and if the developments that are hoped for are realised, the demand for labour will have increased in five years' time to 600,000. It is evident that the importation of Chinese labour relieved a very pressing necessity. The introduction of the Chinese receives the commendation of the author. It has, on the whole, he says, been a success. are ex Very industrious and most desirous of gain, the Chinese make first-class miners. They take to underground work, and the results cellent when they know that they are being paid in proportion to the work done. While they exert themselves as little as possible when on salary, they show great activity when put on piece-work." There is no doubt that if they are employed on piecework excellent results will be obtained. Moreover, the introduction of the Celestials has, according to the author, had a particularly favourable influence on the recruiting of the Kafirs, who now feel that they are no longer masters of the situation. The white miners come in for some severe handling at the hands of the author. He ridicules their an tagonism which forced the Transvaal administration, in admitting the Chinese, to impose restrictions which prevent their best qualities being utilised. The employment of a Celestial on anything approaching skilled labour is strictly prohibited. Yet, as the author points out, the machine-drills are often actually manipulated by a Chinese or Kafir assistant (whose pay does not amount to more than three or four shillings a day), while the white miner in charge (who draws one pound or more a day) looks on and smokes his pipe. In concluding a chapter on the future of the Witwatersrand mining industry, the author says:— "The Transvaal is a fine country, where Nature has been pleased to concentrate enormous mineral wealth, and where there is still a fertile field to exploit. Gold and coal have been found in abundance. The diamond occurs in an eminently favourable condition for exploitation, and a recent notable discovery has added tin to the metals-lead, silver, and copper-which were already known to exist. The possibilities of the Transvaal are considerable, and those who interest themselves in a good venture from the start almost certain to net a profit. The reverse of the medal is that the European markets do not get the chance of participating in South African ventures until they have passed through the hands of a number of intermediaries, all of whom have exacted a profit, and the price at which they are finally offered to the investing public is more in harmony with the illusions of the purchasers than the reality of the facts." F. H. H. are |