THE "SIRIUS" WATER-COOLING AND REGULATING TUBE. SCIENTIFIC WORTHIES A List of this Series of Steel and Photogravure Portraits of Men of Science will be sent post free to any reader of "Nature" on application to the Publishers. ST. MARTIN'S STREET, LONDON, W.C. NEW DOUBLE NATURE says:-"This is one of the most com pact and efficient condensers which has come before our notice. We have tested it for condensing such volatile substances as ether, carbon disulphide, and acetone, and have found that even with rapid distillation the condensation is very complete. Generally speaking, in order to condense these substances satisfactorily, it is necessary to employ a very long condenser; of course, this means using a great amount of bench space. As the new condensers are used in a perpendicular position, the saving in space is very great." SOLE MAKERS BREWSTER, SMITH & CO., 6 CROSS STREET, FINSBURY PAVEMENT, LONDON, E.C. MACMILLAN & CO.'S LIST. New Volume of Essays by Sir ARCHIBALD GEIKIE. LANDSCAPE IN HISTORY AND OTHER ESSAYS. By Sir ARCHIBALD GEIKIE, D.C.L., F.R.S. 8vo. 8s. 6d. net. CONTENTS.-Landscape in History-Landscape and the Imagination-Landscape and Literature-The Origin of the Scenery of the British Isles-The Centenary of Hutton's Theory of the Earth-Geological Time-The Life and Letters of Charles Darwin-Hugh Miller: His Work and Influence-Science in Education-The Roman Campagna. CHEMICAL TECHNOLOGY AND ANALYSIS OF OILS, FATS, AND WAXES. By Dr. J. LEWKOWITSCH, M.A., F.I.C., &c. With 88 Illustrations and Numerous Tables. In 2 Vols. Medium 8vo, gilt tops, 36s. net. NATURE "The standard English book of reference on the subject." THE LABORATORY COMPANION TO FATS AND OILS INDUSTRIES. By DR. J. LEWKOWITSCH, F.I.C., F.C.S. 8vo. 6s. net. NEW EDITION REVISED IN ACCORDANCE WITH THE FOURTH GERMAN EDITION. THEORETICAL CHEMISTRY FROM THE STANDPOINT OF AVOGADRO'S LESSONS IN EXPERIMENTAL AND PRACTICAL GEOMETRY. SECOND EDITION REVISED AND ENLARGED. By H. S. THE LIMITS OF EVOLUTION AND OTHER ESSAYS ILLUSTRATING THE METAPHYSICAL THEORY OF PERSONAL IDEALISM. By G. H. HOWISON, LL.D., Mills Professor of Philosophy in the University of California. Extra crown 8vo. 8s. 6d. net. MACMILLAN AND CO., LIMITED, LONDON. See llustrated article, "Invar and its Applications," INVAR The Alloy of Nickel Steel which has an extremely J. H. AGAR BAUGH, 92 Hatton Garden, London, E.C. FOR SALE, at Reduced Prices. MICROSCOPIC SLIDES (dispersal of Mr. Hornell's collection), see Micro. Editor's note, June No. of Knowledge, Sections of Flower Buds, &c, abo Marine, suitable for Students and Exhibition, new, prices from f. each. MICROSCOPE, Baker's D. P. H. and fittings, £7 165; Beck's London | and fittings, £6 6s.; many others, Pillisher, Ross, &c. Objectives. Bull'sye Condensers. Abbe Condensers. Goerz PRISMATIC BINOCULARS. Photographic Lenses. SURGEON'S OPERATION Outfit, very fine, ew, for sale, cheap. LANTERN SLIDES, English Church Architecture. Many other useful articles. Lists. Mr. HERBERT CLARKE, 104 LEADENHALL STREET, LONDON, (As supplied to the Principal Universities, Technical Schools, &c.) Send for Catalogues to the actual preparers. FLATTERS & GARNETT, Ltd., Dealers in everything Microscopical, 48 Deansgate, Manchester. LANTERNS, MICROSCOPES, NATURE STUDY appliances, &c. PHOTO MICROGRAPHIC APPARATUS. LEACH'S LANTERN MICROSCOPE. Speciality. LANTERN SLIDES from Negatives, Book Illustrations, &c. Correspondence invited. HARVEY Apparatus for estimation of sulphur in spent oxide. BAUSCH & LOMB'S 1905 MODEL PORTABLE MICROSCOPE, embodying several new features, IS NOW THE IDEAL DOCTOR'S & STUDENT'S INSTRUMENT. Full particulars free on application to the Sole Representatives for U.K. and Colonies, A. E. STALEY & CO., 19 THAVIES INN, HOLBORN CIRCUS, LONDON, E.C. Write for Illustrated Microscopical Catalogue (84 pages), 3 Stamps to cover postage. Also Lists of Microtomes, Centrifuges, Photographic Lenses, Shutters & Chemicals of all descriptions, post free. FREDK. JACKSON & Co. (Late MOTTERSHEAD & CO.), 14 CROSS STREET, MANCHESTER Goods Entrance: 10 Half-Moon Street. LABORATORY FURNISHERS, Importers, Manufacturers, and Dealers in Of every Description. AND EVERY LABORATORY REQUIREMENT. Illustrated Catalogue of Apparatus, with Price List of Chemicals, free on application. Telegraphic Address-" APPARATUS, MANCHESTER." Telephone Number-2238. SPINTHARISCOPE as devised by SIR WILLIAM CROOKES. Showing the Scintillations of Radium. PRICE, WITH LENS... £1 1 0 CHEAPER FORM OF ABOVE 15 O The Scintillations seen in this instrument are from Pure Radium Bromide of the Highest Known Activity, and are brighter and more plentiful than those produced from Pitchblende or other bodies of low radio-activity. A. C. COSSOR, 54 Farringdon Rd., London. GOLD MEDAL awarded St. Louis Exhibition, 1904. PEAK (BY APPOINTMENT TO THE ROYAL INSTITUTION OF GREAT BRITAIN.) READING MICROSCOPES, RESISTANCE COILS, &c. 56 CHARING CROSS ROAD, LONDON, W.C. SPECIAL TERMS TO COLLEGES, SCHOOLS, INSTITUTES, &c. IN THE HISTORY OF COAL MINING. Annals of Coal Mining and the Coal Trade. Second Series. By R. L. Galloway. (London: Colliery Guardian Co., Ltd., 1904.) Pp. xvi +409. Na former volume (noticed in NATURE, vol. lix. p. 337) the author carried his annals of coal mining down to the period of the Select Committee of the House of Commons on Accidents in Mines in 1834- He now continues the subject to the passing of the Coal Mines Inspection Act of 1850, and to the establishment of the Royal School of Mines. volume, like its predecessor, is comprehensive and This accurate, and a monument of industry and of thorough technical knowledge. The period of fifteen years reviewed is one of much interest. After ten years of stagnation came a remarkable increase of activity in the coal and iron industries. The chief causes that imparted the impetus were the rapid extension of steam navigation and the mania for constructing railways. Fresh life had been given to the manufacture of iron by the introduction of hot blast, and, owing to its increasing cheapness, the metal was being more largely used in collieries. Steel, however, was still a scarce commodity. chief seat of mining operations at this period was in The the Wear and South Durham district. In South Wales a considerable development of the steam-coal district took place, owing largely to the opening of the West Bute Dock at Cardiff in 1839. In Yorkshire the greatest depth attained in 1841 was at Barnsley, where the coal lay 594 feet below the surface. In Lancashire two pits were begun in 1838 at Pendleton, which reached the coal at 1392 feet, whilst at Apedale, in North Staffordshire, there was a mine with the exceptional depth of 2177 feet. instances of spontaneous issues of fire-damp are reFrequent corded. Full details of the various explosions are given by the author, and the gradual improvements in mining operations are traced. show that the men who did most to advance mining The author's records progress at this period were John Buddle, of Wallsend (1773-1843), Dr. W. R. Clanny (1776-1850), Sir Henry De la Beche (1796-1855), Michael Faraday (1791-1867), Sir Goldsworthy Gurney (1793-1875), Lord Playfair (1818-1898), Sir Warington Smyth (1817-1890), and James Young, of Bathgate (1811-1883), the founder of the Scotch mineral oil industry. Incidentally, Mr. Galloway gives interesting etymological details of some local terms the origin of which is uncertain. Thus, in South Staffordshire and Scotland the word "butty" signifies a comrade or associate. Assuming neighbourhood to have been the original idea, a root for the word is suggested by the author in the term but "as used in the expression "but and ben," applied to a divided house shared by two occupants. Again, what appear to be traces of a primitive state of servitude existed in Staffordshire, where the labourers employed in the haulage of coal continued to be known as bondsmen "-a name probNO. 1842, VOL. 71] 44 361 ably coming down from a remote period; a supposition which receives support from a peculiar service required of them, known as "buildases." This consisted in working at times in the morning without 'receiving any payment beyond a drink of ale. This custom of exacting labour without pay is supposed to represent some ancient service required from their tenants by the monks of the Abbey of Buildwas, in Shropshire, whence the name was derived. Another etymology would have buildas, a contraction of build-house, because the money obtained by means of this unpaid Another curious term was that applied to the small labour enabled the butties to build rows of cottages. stools which in the north of England formed a regular part of the collier's accoutrements. was known as a This stool 66 cracket, a word which appears to be a variety of cricket. In reviewing the history of this interesting period. it is surprising to find what a large number of recent inventions had been anticipated. pneumatic system of haulage, successfully applied by For example, the Blanchet at Epinac, in France, in 1877, was patented in 1845 by Knowles and Woodcock in Lancashire. ing coal adopted on the Continent by Méhu, and subThe use of reciprocating rods to raise vessels containsequently by Guibal, was made the subject of a patent by Slade in 1836. The process of raising mineral in successive stages, proposed for working the deeplevel mines of the Witwatersrand, appears to have been not uncommon during the first half of the nineteenth century. Winding by endless chain, as proposed by O. C. von Verbo in a book published a few months ago, was patented as early as 1789; and in 1839 an applying the brake, invented by John Wild, was in automatic arrangement for cutting off the steam and operation in Lancashire. The well known ventilator patented by W. P. Struvé was identical in principle with the hydraulic air-pump used in the Hartz mines since the Middle Ages. Iron props, adopted in France in 1880, were used in Derbyshire collieries in 1811, as wise were also pieces of timber built up two and two crossAustralian miners at the Day Dawn mine, in Queenspig-sty timbering was introduced as a novelty by the so as to form a square pillar. This so-called land, ten years ago. The title "Annals of Coal Mining " should more properly In one respect the work is open to criticism. have been "Annals of British Coal Mining," inasmuch as Continental and American practice is barely mentioned. This is to be regretted, as during the period reference might usefully have been made. Thus, the under review several events happened abroad to which first Belgian railway was opened in May, 1835, the first German railway in December, 1835, the first French railway in 1837, and the first Austrian railway in 1838. The first railways made in the United States Laurens suggested heating boilers with blast-furnace were coal roads to the mines. In 1835 Thomas and gas. In 1835 Kind improved the methods of deep boring. In 1846 Schönbein discovered gun cotton, and nitroglycerin was invented in the following year. In 1830 the modern mine-theodolite was invented by F. W. Breithaupt, of Cassel, and in 1845, in France, R was the trust-like company of the Loire was formed, that of a diagram in which the ordinate y represents sin A, the prototype of the coal trusts and syndicates given by the conditions, and the abscissa x represents of to-day. Events such as these had a far-reaching sin in an actual stroke in which, for given a, the ball influence on the development of the coal-mining | A passes over or very near to P. A series of values of industry. Special commendation is due to the author for the scrupulous accuracy with which references to original authorities are given, and for the care with which the proof-sheets have been read. Two trifling misprints have, however, escaped detection. Freiberg appears as "Freyburg" (p. 292), and Sir Marc Isambard Brunel as "M. J. Brunel " (p. 291). Mc BENNETT H. BROUGH. MATHEMATICS OF BILLIARDS. Billiards Mathematically Treated. By G. W. Hemming, K.C. Second edition. Pp. 61. (London: Macmillan and Co., Ltd., 1904.) Price 3s. 6d. net. ORE fortunate, or more careful, than most authors, Mr. Hemming, whose recent death will be regretted by many, did not find it necessary in his second edition to make any material alterations in his original work. He added two appendices, iii. and iv., with which alone it is necessary to deal in the present notice. Appendix iii. discusses the comparative advantages of fine and through strokes, with regard to the margin of error permissible in the respective cases. In the figure opposite p. 47, A is the player's ball, O the object ball, and the stroke is to make A, after striking O, pass within a distance of the point P depending on the nature of the stroke, namely, for a cannon a distance equal to the diameter of a ball, for a losing hazard the necessary distance from the centre of the pocket, which may vary between different tables. The angle AOP is given by the conditions of the problem, and in the notation adopted is — A. The angle of aim, OAS, is the thing to be determined. It shall be denoted by a, as in appendix ii. of the first edition. In the present appendix A, is also used for the same angle. S denotes the position of the centre of the striking ball at impact, SO being the common normal. If ASO=”—0, 0 and a are connected by the relation sin /sin a=AO/OS=AO/2 if we denote OS, the diameter of a ball, by 2; and in the special case considered of AO=PO=30, or 15 diameters, we might to a very near approximation use a instead of sin a. Further, the angle OPS is denoted by P1, and the angle of deviation, ASP, by 8. It is then shown that as the equation connecting 8 and 9, tan (+8)=p tan 0, where, for reasons given in the former edition, p=3.5. From this last equation & may be obtained in terms of or a. In fact, tan d=(p-1) sin cos /(cos2 + sin2 ) is easily found. The complete method, were it practicable, would be to find an equation in or a having two roots, one of which, say 1, should correspond to the fine, the other, 2, to the through, stroke, and thence the margin of error might be found for each stroke. This analysis being difficult, a practical solution is obtained by means sin being found corresponding to a series of values of sin A. we draw a freehand curve through them. In general, a line parallel to x for given y cuts this curve in two points, namely, P. in which has the smaller value (the through stroke), and Q,, in which it has the greater value (the fine stroke). It comes next in order to find for any y the margin of error for Py and for Q. This is done by using the formula of appendix ii., first edition. The linear error on the object ball is (AO being 30) 308a. The consequent linear error at P (PO=30) is denoted by E. Then 30da/E gives the margin of error. A new curve, called the blue curve, is then drawn, having for abscissa x=sin 0, and for ordinate y=30da/E, in the same way, by a series of trials, as the first curve. The blue curve has two branches. Then the margin of error for any of the points P, or Qy of the first curve is that ordinate of the blue curve which has the same abscissa. As the result of this method it is found that the margin of error is the same for the through as for the fine stroke, when sin A=0.320, and sin =0.132 for the through, and sin =0.960 for the fine stroke. For smaller values of the through stroke has the advantage; for larger values of the fine stroke, until a certain maximum is reached. In appendix iv., f, the coefficient of friction between two balls at impact, formerly taken as zero, is assumed to have the values 0.01 or 0.02, and it is found that. instead of p=3.5, as above assumed, we should have for f=0.01 p=3.445+0.0625 cos for f=0.02 p =3.391+0.125 cos 0. It will be observed that both these values of p' give very approximately 3.5 when 30°, that is, for the half-ball stroke. Before this notice was in type Mr. Hemming was taken from us by death, to the sincere regret of his many friends, including the present writer. S. H. BURBURY. A MORPHOLOGY OF THE ALGE. Morphologie und Biologie der Algen. By Dr. Friedrich Oltmanns. Vol. i. Special part. Pp. vi+733; illustrated. (Jena: Gustav Fischer, 1904.) THE charming little university town of Freiburg the birthplace of important ideas in an obscure department of natural history. De Bary began there his researches into the life-history of the lower fungi, and afterwards continued them at Halle and Strassburg. Owing to his great work and inspiration we botanists owe a germ-theory of disease a theory which was in time to bear fruit in practical, medical and surgical form in the mighty hands Lord Lister. To Freiburg, then, we come again for a morphology of the kindred group of the Alga. There is a difficulty in understanding how even an assiduous German professor, living so remote from the sea as Freiburg is, can have obtained the inspiration which has guided his research for years past. The |