NOTICES OF THE PROCEEDINGS AT THE MEETINGS OF THE MEMBERS OF THE Eoj>al institution oi (Uteat Britain, WITH ABSTRACTS OF THE DISCOURSES DELIVERED AT THE EVENING MEETINGS. VOLUME JLII. 1887—1889. WITH AN INDEX TO VOLUMES I. TO XIL LONDON: FEINTED BY WILLIAM CLOWES AND SONS, LIMITED. STAMFORD STREET AND CHARING CROSS, 1889. patron. HEP. MOST GRACIOUS MAJESTY QUEEN VICTOKIA. Uice-ilatron anti Jgonorarg if^emlier. HIS ROYAL HIGHNESS THE PEINCE OF WALES, K.G. F.K.S. President — The Duke of Northumberland, E.G. D.C.L. LL.D. Treasurer— Sm James Crichton Browne, M.D. LL.D. F.E.S. — V.P. Honorary Secretary — Sir Frederick Bramwell, Bart. D.C.L. F.R.S. M.Inst.C.E.— F.P. Managers. 1889-90. Sir Frederick Abel, C.B. D.C.L. F.R.S. — V.P. William Crookes, Esq. F.R.S.— F.P. Francis Galton, Esq. M.A. F.R.S. Colonel Janaes A. Grant, C.B. C.S.I. F.R.S.— F.P. The Rt. Hon. Sir William R. Grove, M.A. D.C.L. F.R.S. William Huggins, Esq. D.C.L. LL.D. F.R.S.— F.P. David Edward Hughes, Esq. F.R.S. Rev. John Macnauglit, M.A. Edward Pollock, Esq. William Henry Freece, Esq. F.R.S. M. Inst. C.E. William O. Priestley, M.D. LL.D. F T S John Rae, M.D. LL.D. F.R.S.— F.P. William Chandler Roberts- Austen, Esq. F.R.S. Lord Arthur Russell— V.P. Basil Woodd Smith, Esq. F.R.A.S. Visitors. 1889-90. William Anderson, Esq. M. Inst. C.E. John Birkett, Esq. F.R.C.S. Alfred Carpmael, Esq. James Edmunds, M.D. F.CS. Ernest H. Goold, Esq. F.Z.S. Charles Hawksley, Esq. M. Inst. C.E. John Hopkinson, Esq. M.A. F.R.S. M. Inst. C.E. Victor Hursley, Esq. F.R.S. F.R.C.S. Ludwig Mond, Esq. F.CS. Lachlan Mackintosh Rate, Esq. M.A. Arthur William Riicker, Esq. M.A. F.R.S. John Bell Sedgwick, Esq. J.P. F.R.G.S. Thomas Edward Thorpe, Esq. Ph.D. F.R.S. Thomas Tyrer, Esq. F.CS. James Wimshurst, Esq. professors. ^ Honorary Professor of Natural Philosophy — John Tyndall, Esq. D.C.L. LL.D. F.R.S. &c. Professor of Natural Philosophy. — The Right Hon. Lord Rayleigh, M.A. D.C.L. LL.D. F.R.S. &c. FuUerian Professor of Chemistry — James Dewar, Esq. M.A. F.R.S. Jacksonlan Professor of Natural Experimental Philosophy, Univ. Cambridge. FuUerian Professor of Physiology — George John Romanes, Esq. M.A. LL.D. F.R.S. Honorary Librarian — Mr. Benjamin Vincent. Keeper of the Library and Assistant /Secretary — Mr. Henry Young. Clerk of Accounts and Collector — Mr. Henry C Hughes. Assistants in the Chemical Laboratory — Mr. R. N. Lennox, and Mr. J. W. Heath, Assistant in the Physical Laboratory. — Mr. George Gordon. Assistant in the Library —Mv. William Hartnall. CONTENTS. 1887. Page Jan. 21. — Sir William Thomson. — The Sun's Heat . . .. 1 „ 28. — W. Baldwin Spencer, Esq. — The Pineal Eje in Lizards .. .. - .. .. .. .. 22 Feb. 4. — Edwin Freshfield, Esq. — Some Unpublished Eecords of the City of London .. .. .. 28 „ 7.— General Monthly Meeting 31 ,, 11. — Edward B. Poulton, Esq. — Gilded Chrysalides .. 33 „ 18. — William Crookes, Esq. — Genesis of the Elements 37 „ 25. — Captain W. de W. Abney. — Sunlight Colours .. 61 March 4. — Victor Horsley, Esq.— Brain Surgery in the Stone Ages 72 7.— General Monthly Meeting .. .. .. .. 73 „ 11. — The Ven. Archdeacon Farrar. — Society in the 4th Century A.D 75 „ 18. — George John Eomanes, Esq. — Mental Differences between Men and Women ,. .. ,. 78 „ 25. — The Eight Hon. Lord Eayleigh. — Colours of Thin Plates 81 April 1. — Professor Dewar. — Light as an Analytic Agent 83 „ 4. — General Monthly Meeting .. .. .. .. 94 40143 IV CONTENTS. 1887: Page April 22. — SiE Frederick Abel. — The Work of the Imperial Institute .. .. .. .. .. .. 99 „ 29. — Professor H. S. Hele Shaw. — The Eolling Contact of Bodies . . .. .. .. .. 130 May 2. — Annual Meeting .. ,. .. .. .. 133 „ 6. — Thomas Lauder Brunton, M.D. — The Element of Truth in Popular Beliefs 134 9.— General Monthly Meeting 136 „ 13. — J. S. Buedon-Sandeeson, M.D. — Some Electrical Eishes 139 „ 20. — Benjamin Baker, Esq. — Bridging the Eirth of Forth U2 „ 27.— Edward E. Klein, M.D. — Etiology of Scarlet Fever 150 June 3. — David Gill, Esq. — The Applications of Photo- graphy in Astronomy .. .. ,. .. 168 „ 6. — General Monthly Meeting 173 „ 10, — Thomas Hodgkin, Esq. — Aquileia, the Precursor of Venice 175 July 4. — General Monthly Meeting .. .. .. .. 178 Nov. 7.— General Monthly Meeting 181 Dec. 5.— General Monthly Meeting .. .. .. ... 185 1888. Jan. 20. — The Eight Hon. Lord Eayleigh. — Diffraction of Sound 187 „ 27. — Joseph Thomson, Esq. — The Exploration of Masai- Land 199 Feh. 3, — Frank Crisp, Esq. — Ancient Microscopes {no Abstract) .. ..201 CONTENTS. V 1888. Page Feb. 6.— General Monthly Meeting 201 „ 10. — W. H. Preece, Esq. — Safety Lamps in Collieries 204 5, 17. — Sir Henry Doulton. — Some Developments of English Pottery during the last fifty years .. 212 „ 24. — The Very Eev. G. Granville Bradley — West- minster Abbey .. .. ., .. .. 217 March 2. — 0. Meymott Tidy, Esq. — Poisons and Poisonings 220 „ 5.— General Monthly Meeting .. 230 „ 9. — Leslie Stephen, Esq. — S. T. Coleridge .. .. 233 „ 16. — John Murray, Esq. — Structure, Origin, and Dis- tribution of Cord Eeefs and Islands .. .. 251 „ 23. — Sir Frederick Bramwell. — A Lecture with, — and without, — j)oint (no Abstract) .. .. .. 262 April 2.— General Monthly Meeting .. 268 „ 13. — Professor Flower. — The Pygmy Eaces of Men 266 „ 20. — The Eight Hon. Sir William E. Grove. — Antagonism 27. — James Wimshurst, Esq. Machines .. Electrical Influence Invincible Armada : a 284 300 306 May 1. — Annual Meeting „ 4. — J. K. Laughton, Esq. — The Tercentenary Eetrospect .. .. .. .. 307 7.— General Monthly Meeting 327 „ 11. — Professor W. Chandler Egberts- Austen. — Some curious properties of Metals and Alloys ,, 367 „ 18. — M. Alphonse Eenard. — La reproduction artificielle des roches volcaniques. (In French) .. .. 330 „ 25. — Francis Galton, Esq. — Personal Identification and Description .. .. .. .. .. 346 Jimc 1. — Professor J. A. Ewing. — Earth quakes and how to measure them .. .. .. .. ..361 VI CONTENTS. 1888. Page June 4. — General Monthly Meeting .. .. .. .. 364 „ 8. — Professor Dewar. — Phosphorescence and Ozone 557 July 2.— General Monthly Meeting 370 Nov. 5.— General Monthly Meeting 372 Dec. 3.— General Monthly Meeting 376 1889. Jan. 25. — Professor G. H. Darwin. — Meteorites and the History of Stellar Systems .. .. .. 379 Ych. 1. — Professor W. C. MgIntosh. — The Life-History of a Marine Food-Fish 384 ^^ 4.— General Monthly Meeting 403 ^^ 8. — Sir William Thomson. —Electrostatic Measure- ment .. .. . .. .. .. 561 ,, 15. — Professor A. W. Eucker. — Electrical Stress ,. 406 ,, 22. — Harold Crichton Browne, Estj. —In the Heart of the Atlas (Abstract deferred) .. .. .. 409 March 1. — Edmund Gosse, Esq. — Leigh Hunt .. .. 409 4. —General Monthly Meeting 403 ,, 8. — Professor Oliver Lodge. — The Discharge of a Leyden Jar .. .. .. .. ,. 413 „ 15.— Sir James N. Douglass. — Beacon Lights and Fog Signals 425 jj 22. — Eadweard Muybridge, Esq. — The Science of Animal Locomotion in its Relation to design in Art (illustrated by the Zoopraxiscope) (no Abstract) .. .. .. .. .. .. 444 „ 29. — A. Gordon Salamon, Esq. — Yeast.. .. .. 571 April 1.— General Monthly Meeting .. .. .. .. 445 1889. April May June July Nov. Dec. CONTENTS. 5. — The Eev. Canon Ainger. — True and False Humour in luiteratuYe (^no Abstract) 12. — The Eight Hon, Lord Eayleigh. — Iridescent Crystals 1. — Annual Meeting 3. — Sir Henry E. Eoscoe. — Aluminium 6. — General Monthly Meeting .. 10. — Professor Dewar. — Optical Properties of Oxygen and Ozone .. 17. — Professor Silvanus P. Thompson. — Optical Torque 24. — The Eev. S. J. Perry. — The Solar Surface during the last ten years .. 31. — Professor Demetri Mendeleef. — An attempt to apply to Chemistry on^ of Newton's principles 3.— General Monthly Meeting 7. — Archibald Geikie, Esq. — Eecent Eesearches into the Origin and Age of the Highlands of Scot- land and . the West of Ireland 14.— C. V. Boys, Esq. -Quartz Fibres 1. — General Monthly Meeting .. 4. — General Monthly Meeting .. 2. — General Monthly Meeting .. Index to Volumes I. to XII. Vll Page 446 447 450 451 464 468 474 498 506 528 547 563 565 569 681 ( viii ) PLATE. Page Map of the British Empire (Qncen's Jubilee) .. .. .. 99 3Koi)aI institution of ffireat iiStft^.^®^ WEEKLY EVENING MEETINd'^ Friday, January 21, 1887. William Huggins, Esq. D.C.L. LL.D. F.R.S. Manager^ President, in the Chair. Sir William Thomson, LL.D. F.R.S. M.B.L PROFESSOR OF NATURAL PHILOSOPHY IN THE DNIVERSITT OF GLASGOW. The Sun's Heat. From human history we know that for several thousand years the sun has been giving heat and light to the earth as at present, possibly with some considerable fluctuations, and possibly with some not very small progressive variation. The records of agriculture, and the natural history of plants and animals within the time of human history, abound with evidence that there has been no exceedingly great change in the intensity of the sun's heat and light within the last three thousand years ; but for all that, there may have been variations of quite as much as 5 or lO^per cent., as we may judge by considering that the intensity of the "solar radiation to the earth is 6 J per cent, greater in January than in July ; and neither at the equator nor in the northern or southern hemispheres has this differ- ence been discovered by experience or general observation of any kind. But as for the mere age of the sun, irrespective of the question of uniformity, we have proof of something vastly more than three thousand years in geological history, with its irrefragable evidence of continuity of life on the earth in time past for tens of thousands, and probably for millions of years. Here, then, we have a splendid subject for contemplation and research in Natural Philosophy or Physics — the science of dead matter. The sun, a mere piece of matter of the moderate dimensions which we know it to have, bounded all round by cold ether,* has been doing work at the rate of four hundred and seventy-six thousand million million million horse-power for three thousand years ; and at * The sun warms and lights the earth by wave motion, excited in virtue of his white-Lot temperature, and transmitted through a material commonly called the luminiferous ether, which fills all space as far as the remotest star, and has the property of transmitting radiant heat (or light) without itself becoming heated. I feel that I have a right to drop the adjective luminiferous, because the medium, far above the earth's surface, through which we receive sun-heat (or light), and through which the planets move, was called ether 2000 years before chemists usurped the name for " sulphuric ether," " muriatic ether," and other compounds, fancifully supposed to be peculiarly ethereal ; and I trust that chemists of the present day will not be angry with me if I use the word ether, pure and simple, to denote the medium whose undulatory motions constitute radiant heat (or light). YoL. XII. (No. 81.)^ B 2 Sir William Thomson [Jan. 21, possibly a higher, certainly not much lower, rate for a few million years. How is this to be explained ? Natural philosophy cannot evade the question, and no physicist who is not engaged in trying to answer it can have any other justification than that his whole working time is occupied with work on some other subject or subjects of his province by which he has more hope of being able to advance science. It may be taken as an established result of scientific inquiry that the sun is not a burning fire, and is merely a white hot fluid mass cooling, with some little accession of fresh energy by meteors occasionally falling in, but of very small account in comijarison with the whole energy of heat which he gives out from year to year. Helm- holtz's form of the meteoric theory of the origin of the sun's heat, may be accepted as having the highest degree of scientific probability that can be assigned to any assumption regarding actions of prehis- toric times. The essential principle of the explanation is this ; at some period of time, long past, the sun's initial heat was generated by the collision of pieces of matter gravitationally attracted together from distant space to build up his present mass ; and shrinkage due to cooling gives, through the work done by the mutual gravitation of all parts of the shrinking mass, the vast heat-storage capacity in virtue of which the cooling has been, and continues to be, so slow. In some otherwise excellent books it is " paradoxically " stated that the sun is becoming hotter because of the condensation.* Para- doxes have no place in science. Their removal is the substitution of true for false statements and thoughts, not always so easily effected as in the present case. The truth is, that it is because the sun is becoming less hot in places of equal density that his mass is allowed to yield gradually under the condensing tendency of gravity and thus from age to age cooling and condensation go on together. An essential detail of Helmholtz's theory of solar heat is that the sun must be fluid, because even though given at any moment hot enough from the surface to any depth, however great, inwards, to be brilliantly incandescent, the conduction of heat from within through solid matter of even the highest conducting quality known to us, would not suffice to maintain the incandescence of the surface for more than a few hours, after which all would be darkness. Observa- ^ tion confirms this conclusion so far as the outward appearance of the * [Note of February 21, 1887. — The " paradox " referred to here, is, as I now find, merely a mis-statement (faulty and manifestly paradoxical through the omission of an essential condition) of an astonishing and most important con- clusion of a paper by J. Homer Lane, which appeared iu the ' American Journal of Science, for July 1870 (referred to more particularly on p. 11 below). In Newcomb's ' Popular Astronomy,' first edition, p. 508, the omission is supplied in a footnote, giving a clear popular explanation of the dynamics of Lane's con- clusion; and the subject is similarly explained in Ball's ' Story of the Heavens,' pp. 501, 502, and 503, with complete avoidance of the " paradox." And now I take this opportunity of correcting my hasty correction of the " paradox " by the insertion of the five words in italics added to line 6 of the paragraph. — W. T.] 1887.] on the Sun's Heat. 3 sun is concerned, but does not suffice to disprove the idea which was so eloquently set forth by Sir John Herschel, and which prevailed till thirty or forty years ago, that the sun is a solid nucleus inclosed in a sheet of violently agitated flame. In reality, the matter of the outer shell of the sun, from which the heat is radiated outwards, must in cooling become denser, and so becoming unstable in its high position must fall down, and hotter fluid from within must rush up to take its place. The tremendous currents thus continually pro- duced in this great mass of flaming fluid constitute the province of the newly-developed science of solar physics, which, with its mar- vellous instrument of research — the spectroscope — is yearly and daily giving us more and more knowledge of the actual motions of the different ingredients, and of the splendid and all-important resulting phenomena. To form some idea of the amount of the heat which is being continually carried up to the sun's surface and radiated out into space, and of the dynamical relations between it and the solar gravitation, let us first divide that prodigious number (476 X 10^^) of horse-jDower by the number (6 • 1 X 10^^) of square metres * in the sun's surface, and we find 78,000 horse-power as the mechanical value of the radia- tion per square metre. Imagine, then, the engines of eight ironclads applied, by ideal mechanism of countless shafts, pulleys, and belts, to do all their available work of, say 10,000 horse-power each, in perpetuity driving one small paddle in a fluid contained in a square metre vat. The same heat would be given out from the square metre * surface of the fluid as is given out from every square metre of the sun's surface. But now to pass from a practically impossible combination of engines, and a physically impossible paddle and fluid and containing vessel, towards a more practical combination of matter for producing * A square metre is about 10| (more nearly 10*764) square feet, or a square yard and a fifth (more nearly 1*196 square yards). The metre is a little less than 40 inches (39 '37 inches = 3*281 feet = 1*094 yards). The kilometre, which we shall have to use presently, being a thousand metres, is a short mile as it were (*6214 of the British statute mile). Thus in round numbers 62 statute miles is equal to 100 kilometres, and 161 kilometres is equal to 100 statute miles. The awful and unnecessary toil and waste of brain power involved in the use of the British system of inches, feet, yards, perches, or rods, or poles, " chains," furlongs, British statute miles, nautical miles, square rod (30J square yards)! rood (1210 square yards)! acre (4 roods), may be my apology, but it is only a part of my reason, for not reckoning the sun's area in acres, his activity in horse-power per square inch or per square foot, and his radius, and the earth's distance from him in British statute miles, and for using exclusively the one- denominational system introduced by the French ninety years ago, and now in common use in every civilised country of the world, except England and the United States of North America. The British ton is 1 *016 times the French ton, or weight of a cubic metre of cold water (1016 kilogrammes). The French ton, of 1000 kilogrammes, is -9842 of the British ton. Thus for many practical reckonings, such as those of the present paper, the difference between the British and the French ton may be neglected. B 2 4 Sir William Thomson [Jan. 21, the same effect: still keep the ideal vat and paddle and fluid, bnt place the vat on the surface of a cool, solid, homogeneous globe of the same size (697,000 kilometres radius) as the sun, and of density (1'4) equal to the sun's mean density. Instead of using steam-power, let the paddle be driven by a weight descending in a pit excavated below the vat. As the simplest possible mechanism, take a long vertical shaft, with the paddle mounted on the top of it so as to turn horizontally. Let the weight be a nut working on a screw-thread on the vertical shaft, with guides to prevent the nut from turning — the screw and the guides being all absolutely frictionless. Let the pit be a metre square at its upper end, and let it be excavated quite down to the sun's centre, everywhere of square horizontal section, and tapering uniformly to a point in the centre. Let the weight be simply the excavated matter of the sun's mass, with merely a little clearance space between it and the four sides of the pit, and with a kilometre or so cut off the lower pointed end to allow space for its descent. The mass of this weight is 326 million tons. Its heaviness, three-quarters of the heaviness of an equal mass at the sun's surface, is 244 million tons solar surface-heaviness. Now a horse-power is, per hour, 270 metre-tons, terrestrial surface-heaviness ; or 10 metre-tons, solar surface-heaviness, because a ton of matter is twenty-seven times as heavy at the sun's surface as at the earth's. To do 78,000 horse- power, or 780,000 metre-tons solar surface-heaviness per hour, our weight must therefore descend at the rate of one metre in 313 hours, or about 28 metres per year. To advance another step, still through impracticable mechanism, towards the practical method by which the sun's heat is produced, let the thread of the screw be of uniformly decreasing steepness from the surface downwards, so that the velocity of the weight, as it is allowed to descend by the turning of the screw, shall be in simple proportion to distance from the sun's centre. This will involve a uniform con- densation of the material of the weight ; but a condensation so ex- ceedingly small in the course even of tens of thousands of years, that, whatever be the supposed material, metal or stone, of the weight, the elastic resistance against the condensation will be utterly imper- ceptible in comparison with the gravitational forces with which we are concerned. The work done per metre of descent of the top end of the weight will be just four-fifths of what it was when the thread of the screw was uniform. Thus, to do the 78,000 horse-power of work, the top end of the weight must descend at the rate of 35 metres per year : or 70 kilometres per 2000 years. Now let the whole surface of our cool solid sun be divided into squares, for example as nearly as may be of one square metre area each, and let the whole mass of the sun be divided into long inverted pyramids or pointed rods, each 697,000 kilometres long, with their points meeting at the centre. Let each be mounted on a screw, as already described for the long tapering weight which we first con- sidered ; and let the paddle at the top end of each screw-shaft revolve 1887.] on the Suns Heat. 6 in a fluid, not now confined to a vat, but covering the wliole surface of the sun to a depth of a few metres or kilometres. Arrange the viscosity of the fluid and the size of each paddle so as to let the paddle turn just so fast as to allow the top end of each pointed rod to descend at the rate of 35 metres per year. The whole fluid will, by the work which the paddles do in it, be made incandescent, and it will give out heat and light to just about the same amount as is actually done by the sun. If the fluid be a few thousand kilometres deep over the paddles, it would be impossible, by any of the ap- pliances of solar physics, to see the difference between our model mechanical sun and the true sun. To do away with the last vestige of impracticable mechanism in which the heavinesses of all parts of each long rod are supported on the thread of an ideal screw cut on a vertical shaft of ideal matter, absolutely hard and absolutely frictionless : first, go back a step to our supposition of just one such rod and screw working in a single pit excavated down to the centre of the sun, and let us suppose all the rest of the sun's mass to be rigid and absolutely impervious to heat. Warm up the matter of the pyramidal rod to such a temper- ature that its material melts and experiences as much of Sir HumjDhry Davy's " repulsive motion " as suffices to keep it balanced as a fluid, without either sinking or rising from the position in which it was held by the thread of the screw. When the matter is thus held up without the screw, take away the screw or let it melt in its place. We should thus have a pit from the sun's surface to his centre, of a square metre area at the surface, full of incandescent fluid, which we may suppose to be of the actual ingredients of the solar substance. This fluid, having at the first instant the temperature with which the paddle left it, would at the first instant continue radiating heat just as it did wheu the paddle was kept moving ; but it would quickly become much cooler at its surface, and to a distance of a few metres down. Currents of less hot fluid tumbling down, and hotter fluid coming up from below, in irregular whirls, would carry the cooled fluid down from the surface, and bring up hotter fluid from below, but this mixing could not gc^on through a depth of very many metres to a sufficient degree to keep up anything approaching to the high temperature maintained by the paddle ; and after a few hours or days, solidification would commence at the surface. If the solidified matter floats on the fluid, at the same temperature, below it, the crust would simply thicken as ice on a lake thickens in frosty weather ; but if, as is more probable, solid matter, of such ingredients as the sun is composed of, sinks in the liquid when both are at the melting tem- perature of the substance, thin films of the upper crust would fall in, and continue falling in, until, for several metres downwards, the whole mass of mixed solid and fluid becomes stiff" enough (like the stiffness of paste or of mortar) to prevent the frozen film from fall- ing down from the surface. The surface film would then quickly thicken, and in the course of a few hours or days become less than 6 Sir William Thomson [Jan. 21, red-hot on its upper surface, the whole pit full of fluid would go on cooling with extreme slowness until, after possibly about a million million million years or so, it would be all at the same temperature as the space to which its upper end radiates. Let precisely what we have been considering be done for every one of our pyramidal rods, with, however, in the first place, thin partitions of matter impervious to heat separating every pit from its four surrounding neighbours. Precisely the same series of events as we have been considering will take place in every one of the pits. Suppose the whole complex mass to be rotating at the rate of once round in twenty-five days, which is, about as exactly as we know it, the time of the sun's rotation about his axis. Now at the instant when the paddle stops let all the partitions be annulled, so that there shall be perfect freedom for currents to flow unresisted in any direction, except so far as resisted by the viscosity of the fluid, and leave the piece of matter, which we may now call the Sun, to himself. He will immediately begin showing all the phenomena known in solar physics. Of course the observer might have to wait a few years for sunspots, and a few quarter- centuries to discover periods of sunspots, but they would, I think 1 may say probably, all be there just as they are, because I think we may feel that it is most probable that all these actions are due to the sun's own substance, and not to external influences of any kind. It is, however, quite possible, and indeed many who know most of the subject think it probable, that some of the chief phenomena due to sunspots arise from influxes of meteoric matter circling round the sun. The energy of chemical combination is as nothing compared with the gravitational energy of shrinkage, to which the sun's activity is almost wholly due. A body falling forty-six kilometres to the sun's surface or through the suns atmosphere, has as much work done on it by gravity, as corresponds to a high estimate of chemical energy in the burning of combustible materials. But chemical combinations and dissociations may, as urged by Lockyer, in his book on the ' Chemistry of the Sun,' just now published, be thoroughly potent determining influences on some of the features of non-uniformity of the brightness in the grand phenomena of sun- spots, hydrogen flames, and corona, which make the province of solar physics. But these are questions belonging to a very splendid branch of solar science to which only allusion can be made at the present time. What concerns us as to the explanation of sun-light and sun-heat may be summarised in two propositions : — (1) Gigantic currents throughout the sun's liquid mass are con- tinually maintained by fluid, slightly cooled by radiation falling down from the surface, and hotter fluid rushing up to take its place. 1887. J on the Sun's Heat 7 (2) The work done in any time by the mutual gravitation of all the parts of the fluid, as it shrinks in virtue of the lowering of its temperature, is but little less than (so little less than, that we may regard it as practically equal to) the dynamical equivalent of the heat that is radiated from the sun in the same time. The rate of shrinkage corresponding to the present rate of solar radiation has been proved to us, by the consideration of our dynamical model, to be 35 metres on the radius per year, or one ten-thousandth of its own length on the radius per two thousand years. Hence, if the solar radiation has been about the same as at present for two hundred thousand years, his radius must have been greater by one per cent, two hundred thousand years ago than at present. If we wish to carry our calculations much farther back or forward than two hundred thousand years, we must reckon by differences of the reciprocal of the sun's radius, and not by dif- ferences simply of the radius, to take into account the change of density (which, for example, would be three per cent, for one per cent, change of the radius). Thus the rule, easily worked out according to the principles illustrated by our mechanical model, is this : — Equal differences of the reciprocal of the radius correspond to equal quantities of heat radiated away from million of years to million of years. Take two examples — (1) If in past time there has been as much as fifteen million times the heat radiated from the sun as is at present radiated out in one year, the solar radius must have been four times as great as at present. (2) If the sun's effective thermal capacity can be maintained by shrinkage till twenty million times the present year's amount of heat is radiated away, the sun's radius must be half what it is now. But it is to be remarked that the density which this would imply, being 11*2 times the density of water, or just about the density of lead, is probably too ^great to allow the free shrinkage as of a cooling gas to be still continued without obstruction through over- crowding of the molecules. It seems, therefore, most probable that we cannot for the future reckon on more of solar radiation than, if so much as, twenty million times the amount at present radiated out in a year. It is also to be remarked that the greatly diminished radiating surface, at a much lower temperature, would give out annually much less heat than the sun in his present condition gives. The same considerations led Newcomb to the conclusion " that it is hardly likely that the sun can continue to give sufficient heat to support life on the earth (such life as we now are acquainted with, at least) for ten million years from the present time." In all our calculations hitherto we have for simplicity taken the density as uniform throughout, and equal to the true mean 8 Sir William Thomson [Jan. 21, density of the sun, being about 1 • 4 times the density of water, or about a quarter of the earth's mean density. In reality the density in the upper parts of the sun's mass must be something less than this, and something considerably more than this in the central parts, because of the pressure in the interior increasing to something enormously great at the centre. If we knew the distribution of interior density we could easily modify our calculations accord- ingly ; but it does not seem probable that the correction could, with any probable assumption as to the greatness of the density throughout a considerable proportion of the sun's interior, add more than a few million years to the past of solar heat, and what could be added to the past must be taken from the future. In our calculations we have taken Pouillet's number for the total activity of solar radiation, which practically agrees with Herschel's. Forbes * showed the necessity for correcting tlie mode of alloAving for atmospheric absorption used by his two predecessors in estimating the total amount of solar radiation, and he was thus led to a number 1 • 6 times theirs. Forty years later Langley,t in an excellently worked out consideration of the whole question of absorption by our atmosphere, of radiant heat of all wave-lengths, accepts and confirms Forbes's reasoning, and by fresh ol)servations in very favourable circumstances on Mount Whitney, 15,000 feet above the sea-level, finds a number a little greater still than Forbes (1*7, instead of Forbes' 1 • 6, times Pouillet's number). Thus Laugley's measurement of solar radiation corresponds to 133,000 horse-power per square metre, instead of the 78,000 horse-power which we have taken, and diminishes each of our times in the ratio of 1 to 1 • 7. Thus, instead of Helmholtz's twenty million years, which was founded on Pouillet's estimate, we have only twelve millions, and similarly with all our other time reckonings based on Pouillet's results. In the circum- stances, and taking fully into account all possibilities of greater density in the sun's interior, and of greater or less activity of radiation in past ages, it would, I think, be exceedingly rash to assume as probable anything more than twenty million years of the sun's light in the past history of the earth, or to reckon on more than five or six million years of sunlight for time to come. We have seen that the sun draws on no external source for the heat he radiates out from year to year, and that the whole energy of this heat is due to the mutual attraction between his parts acting in conformity with the Newtonian law of gravitation. We have seen how an ideal mechanism, easily imagined and understood, though infinitely far from possibility of realisation, could direct the work done by mutual gravitation between all the parts of the shrinking mass, to actually generate its heat-equivalent in an ocean of white- hot liquid covering the sun's surface, and so keep it white-hot while * 'Edin. New Phil. Journal,' vol. xxxvi. 1844. t 'American Journal of Science,' vol. xxvi. March, 1883. 1887.] on the Suiis Heat. 9 constantly radiating out heat at the actual rate of the sun's heat- giving activity. Let us now consider a little more in detail the real forces and movements actually concerned in the process of cooling by radiation from the uttermost region of the sun, the falling inwards of the fluid thus cooled, the consequent mixing up of the whole mass of the sun, the resulting diminished elastic resistance to pressure in equi-dense parts, and the consequent shrinkage of the whole mass under the influence of mutual gravitation. I must first explain that this " elastic resistance to pressure " is due to heat, and is, in fact, what I have, in the present lecture, called " Sir Humphry Davy's repulsive motion " (p. 5). I called it so because Davy first used the expression " repulsive motion " to describe the fine intermolecular motions to which he and other founders of the Kinetic Theory of Heat attributed the elastic resistance to compression presented by gases and fluids. Imagine, instead of the atoms and molecules of the various substances which constitute the sun's mass, a vast number of elastic globes, like schoolboys' marbles or billiard balls. Consider first, anywhere on our earth a few million such balls put into a room, large enough to hold a thousand times their number, with perfectly hard walls and ceiling, but with a real wooden floor ; or, what would be still more convenient for our purpose, a floor of thin elastic sheet steel, supported by joists close enough together to prevent it from drooping inconveniently in any part. Suppose in the beginning the marbles to be lying motionless on the floor. In this condition they represent the atoms of a gas, as for instance, oxygen, nitrogen, or hydrogen, absolutely deprived of heat, and therefore lying frozen, or as molecular dust strewn on the floor of the containing vessel. If now a lamp be applied below the oxygen, nitrogen, or hydrogen, the substance becoming warmed by heat conducted through the floor, will rise from its condition of absolutely cold solid, or of incoherent molecular dust, and will spread as a gas through the whole enclosed space. If more and more heat be applied by the lamp the pressure of the gas outwards in all directions against the inside of the enclosing vessel will become greater and greater. As a rude mechanical analogue to this warming of a gas by heat conducted through the floor of its containing vessel, from a lamp held below it, return to our room with floor strewTi with marbles, and employ workmen to go below the floor and strike its underside in a great many places vehemently with mallets. The marbles in immediate contact with the floor will begin to jump from it and fall sharply back again (like water in a pot on a fire simmering before it boils). If the w^orkmen work energetically enough there will be more and more of commotion in the heap, till every one of the balls gets into a state of irregular vibration, up and down, or obliquely, or horizontally, but in no fixed direction ; and by mutual jostling the heap swells up till the ceiling of the room prevents it from swelling any further. Suppose now the floor to become, like the walls and 10 Sir William Thomson [Jan. 21, ceiling, absolutely rigid. Tlie workmen may cease their work of hammering, which would now be no more availing to augment the motions of the marbles within, than would be a lamp applied outside to warm the contents of a vessel, if the vessel were made of ideal matter impermeable to heat. The marbles being perfectly elastic will continue for ever * flying about in their room striking the walls and floor and ceiling and one another, and remaining in a constant average condition of denser crowd just over the floor and less and less dense up to the ceiling. In this constant average condition the average velocity of the marbles will be the same all through the crowd, from ceiling to floor, and will be the same in all directions, horizontal, or vertical, or inclined. The continually repeated blows upon any part of the walls or ceiling will in the aggregate be equivalent to a continuous pressure which will be in simple proportion to the average density of the crowd at the place. The diminution of pressure and density from the floor upwards will be precisely the same as that of the density and pressure of our atmosphere calculated on the supposition of equal temperature at all heights, according to the well-known formula and tables for finding heights by the barometer. In reality the temperature of the atmosphere is not uniform from the ground upwards, but diminishes at the rate of about 1° C. for every 162 metres of vertical ascent in free air, undistui'bed by moun- tains, according to observations made in balloons by the late Mr. Welsh, of Kew, through a large range of heights. This diminution of temperature upwards in our terrestrial atmosphere is most impor- tant and suggestive in respect to the constitution of the solar atmosphere, and not merely of the atmosphere or outer shell of the sun, but of the whole interior fluid mass with which it is continuous. The two cases have so much in common that there is in each case loss of heat from the outer parts of the atmosphere by radiation into space, and that in consequence circulating currents are produced through the continuous fluid, by which a thorough mixing up and down is constantly performed. In the case of the terrestrial atmosphere the lowest parts receive by contact heat from the solid earth, warmed daily by the sun's radiation. On the average of night and day, as the air does not become warmer on the whole, it must radiate out into * To justify this statement I must warn the reader that the ideal perfectly elastic balls which we are imagining must be supposed somehow to have such a structure that each takes only a definite average proportion of its share of the kinetic energy of the whole multitude, so that on the average there is a constant proportion of energy in the translatory motions of the balls ; the other part being the vibratory or rotational motions of the parts of each ball. For simplicity also we suppose the balls to be perfectly smooth and frictionless, so that we shall not be troubled by need to consifler them as having any rotatory motions, such as real balls with real frictional collisions would acquire. The ratio of the two kinds of energy for ordinary gases, according to Clausius, to whom is due this essential contribution to the kinetic theory, is — of the whole energy, three-fifths trans-? lational to two-fifths vibrational. 1887.] on the Sun's Heat 11 space as much heat as all that it gets, both from the earth by contact, and by radiation of heat from the earth, and by intercepted radiation from the sun on its way to the earth. In the case of the sim the heat radiated from the outer parts of the atmosphere is wholly derived from the interior. In both cases the whole fluid mass is kept thoroughly mixed by currents of cooled fluid coming down and warmer fluid rising to take its place, and to be cooled and descend in its turn. Kow it is a well known property of gases and of fluids generally (except some special cases, as that of water within a few degrees of its freezing temperature, in which the fluid under constant pressure contracts with rise of temperature) that condensation and rarefactions, effected by augmentations and diminutions of pressure from without, produce elevations and lowerings of temperature in circumstances in which the gas is prevented from either taking heat from or giving heat to any material external to it. Thus a quantity of air or other gas taken at ordinary temj)erature (say 15° C. or 59^ F.) and expanded to double its bulk becomes 71° C. cooler; and if the expansion is continued to thirty-two times its original bulk it becomes cooled 148° farther, or down to about 200° C. below the temperature of freezing water, or to within 73° of absolute cold. Such changes as these actually take place in masses^of air rising in the atmosphere to heights of eight or nine kilometers, or of twenty or twenty-five kilometers. Corresponding differences of temperature there certainly are throughout the fluid mass of the sun, but of very different magnitudes because of the twenty-seven fold greater gravity at the sun's surface, the vastness of the space through which there is free circulation of fluid, and last, though not least, the enormously higher temperature of the solar fluid than of the terrestrial atmosphere at points of equal density in the two. This view of the solar constitution has been treated mathematically with great power by Mr. J. Homer Lane, of Washington, U.S., in a very important paper read before the National Academy of Sciences, of the XJnited States in April 1869, and published with further developments in the ' American Journal of Science,' for July 1870. Mr. Lane, by strict mathematical treatment finds the law of distribution of density and temperature all through a globe of homogeneous gas left to itself in space, and losing heat by radiation outwards so slowly that the heat-carrying currents produce but little disturbance from the globular form. One very remarkable and important result which he finds is, that the density at the centre is about twenty * times the mean density ; and this, whether the mass be large or small, and whether of oxygen, nitrogen, or hydrogen, or other substance ; provided only it be of one kind of gas throughout, and that the density in the central parts is not too great to allow the condensation to take place, according to ♦ "Working out Lane's problem independently, I find 22^ as very nearly the exact number. 12 Sir William Thomson [Jan. 21, the ordinary gaseous law of density, in simple proportion to pressure for the same temperatures. We know this law to hold with somewhat close accuracy for common air, and for each of its two chief constitu- ents, oxygen and nitrogen, separately, and for hydrogen, to densities of about two hundred times their densities at our ordinary atmo- spheric pressure. But when the compressing force is sufficiently increased, they all show greater resistance to condensation than according to the law of simple proportion, and it seems most probable that there is for every gas a limit beyond which the density cannot be increased by any j)ressure however great. Lane remarks that the density at the centre of the sun would be "nearly one-third greater than that of the metal platinum," if the gaseous law held up to so great a decree of condensation for the ingredients of the sun's mass ; but he^ does not suggest this supposition as probable, and he no doubt agrees with the general opinion that in all pro- bability the ingredients of the sun's mass, at the actual temperatures corresponding to their positions in his interior, obey the simple gaseous law through but a comparatively small space inwards from the surface ; and that in the central regions they are much less con- densed than according to that law. According to the simple gaseous law, the sun's central density would be thirty-one times that of water ; we may assume that it is in all probability much less than this, though considerably greater than the mean density, 1-4. This is a wide range of uncertainty, but it would be unwise at present to narrow it, ignorant as we are of the main ingredients of the sun's whole mass, and of the laws of pressure, density, and tempera- ture, even for known kinds of matter at very great pressures and very high temperatures. The question. Is the sun becoming colder or hotter ? is an exceed- ingly complicated one, and, in fact, either to put it or to answer it is a paradox, unless we define exactly where the temperature is to be reckoned. If we ask, How does the temperature of equi-dense portions of the sun vary from age to age ? the answer certainly is that the matter of the sun of which the density has any stated value, for example, the ordinary density of our atmosj)here, becomes always less and less hot, whatever be its place in the fluid, and whatever be the law of compression of the fluid, whether the simple gaseous law or anything from that to absolute incompressibility. But the distance inwards from the surface at which a constant density is to be found diminishes with shrinkage, and thus it may be that at constant depths inwards from the bounding surface the temperature is be- coming higher and higher. This would certainly be the case if the gaseous law of condensation held throughout, but even then the effective radiational temperature, in virtue of which the sun sheds his heat outwards, might be becoming lower, because the temperatures of equi-dense portions are clearly becoming lower under all circum- stances. Leaving now these complicated and difficult questions to the 1887.] on the Sun's Heat. 18 scientific investigators who are devoting themselves to advancing the science of solar physics, consider the easily understood ques- tion, What is the temperature of the centre of the sun at any time, and does it rise or fall as time advances ? If we go back a few million years to a time when we may believe the sun to have been wholly gaseous to the centre, then certainly the central tempera- ture must have been augmenting ; again, if, as is possible though not probable at the present time, but may probably be the case at some future time, there be a solid nucleus, then certainly the central temperature would be augmenting, because the conduction of heat outwards through the solid would be too slow to compensate the augmentation of pressure due to augmentation of gravity in the shrinking fluid around the solid. But at a certain time in the history of a wholly fluid globe, primitively rare enough through- out to be gaseous, shrinking under the influence of its own gravi- tation and its radiation of heat outwards into cold surrounding space, when the central parts have become so much condensed as to resist further condensation greatly more than according to the gaseous law of simple proportions, it seems to me certain that the early process of becoming warmer, which has been demonstrated by Lane, and Newcomb, and Ball, must cease, and that the central temperature must begin to diminish on account of the cooling by radiation from the surface, and the niixing of the cooled fluid through- out the interior. Now we come to the most interesting part of our subject — the early history of the Sun. Five or ten million years ago he may have been about double his present diameter and an eighth of his present mean density, or • 175 of the density of water ; but we cannot, with any probability of argument or speculation, go on continuously much beyond that. We cannot, however, help asking the question, What was the condition cf the sun's matter before it came together and became hot? It may have been two cool solid masses, which collided with the velocity due to their mutual gravitation ; or, but with enormously less of probability, it may have been two masses colliding with velocities considerably greater than the velocities due to mutual gravitation. This last supposition implies that, calling the two bodies A and B for brevity, the motion of the centre of inertia of B rela- tively to A, must, when the distances between them was great, have been directed with great exactness to pass through the centre of inertia of A ; such great exactness that the rotational momentum, or " moment of momentum," * after collision was no more than to let * This is a technical expression in dynamics which means the importance of motion relatively to revolution or rotation round an axis. Momentum is an expression given about a hundred and fifty years ago (when mathematicians and other learned men spoke and wrote Latin) to signify translational importance of motion. Moment of a couple, moment of a magnet, moment of inertia, moment of force round an axis, moment of momentum round an axis, and corresponding verbal combinations in French and German, are expressions which have been 14 Sir William Thomson [Jan. 21, the sun have his present slow rotation when shrunk to his present dimensions. This exceedingly exact aiming of the one body at the other, so to speak, is, on the dry theory of probability, exceedingly improbable. On the other hand, there is certainty that the two bodies A and B at rest in space if left to themselves undisturbed by other bodies and only influenced by their mutual gravitation, shall collide with direct impact, and therefore with no notion of their centre of inertia, and no rotational momentum of the compound body after the collision. Thus we see that the dry probability of collision between two neigh- bours of a vast number of mutually attracting bodies widely scat- tered through space is much greater if the bodies be all given a rest, than if they be given moving in any random directions and with any velocities considerable in comparison with the velocities which they would acquire in falling from rest into collision. In this con- nection it is most interesting to know from stellar astronomy, aided so splendidly as it has recently been by the spectroscope, that the relative motions of the visible stars and our sun are generally very small in comparison with the velocity (612 kilometers per second) which a body would acquire in falling into the sun, and are compar- able with the moderate little velocity (29-5 kilometres per second) of the earth in her orbit round the sun. To fix the ideas, think of two cool solid globes, each of the same mean density as the earth, and of half the sun's diameter ; given at rest, or nearly at rest, at a distance asunder equal to twice the earth's distance from the sun. They will fall together and collide in exactly half a year. The collision will last for about half an hour, in the course of which they will be transformed into a violently agitated incandescent fluid mass flying outward from the line of the motion before the collision, and swelling to a bulk several times greater than the sum of the original bulks of the two globes.* How far the fluid mass will fly out all round from the line of collision it is impossible to say. The motion is too complicated to be fully investigated by any known mathematical method ; but with sufficient patience a mathematician might be able to calculate it with some fair approxima- tion to the truth. The distance reached by the extreme circular introduced within the last sixty years (by scientists speaking as now, each his own vernacular) to signify the importance of the special subject referred to in each case. The expression moment of momentum is highly valuable and con- venient in dynamical science, and it constitutes a curious philological monument of scientific history. * Such incidents seem to happen occasionally in the universe. Laplace says some stars " have suddenly appeared, and then disappeared, after having shone for several months with the most brilliant splendour. Such was the star observed by Tycho Brahe in the year 1572, in the constellation Cassiopeia. In a short time it surpassed the most brilliant stars, and even Jupiter itself. Its light then waned away, and finally disappeared sixteen months after its discovery. Its colour underwent several changes ; it was at first of a brilliant white, then of a reddish vellow, and finally of a lead-coloured white, like to Saturn." (Harte's translation of Laplace's ' System of the World.' Dublin, 1830.) 1887.] on the Sun's Heat. 15 fringe of the fluid mass would probably be mucb less than the distance fallen by each globe before the collision, because the trans- lational motion of the molecules constituting the heat into which the whole energy of the original fall of the globes become transformed in the first collision, is probably about three-fifths of the whole amount of that energy. The time of flying out would probably be less than half a year, when the fluid mass mast begin to fall in again to- wards the axis. In something less than a year after the first collision the fluid will again be in a state of maximum crowding round the centre, and this time probably even more violently agitated than it was immediately after the first collision ; and it will again fly outward, but this time axially towards the places whence the two globes fell. It will again fall inwards, and after a rapidly subsiding series of quicker and quicker oscillations it will subside, probably in the course of two or three years, into a globular star of al30ut the same dimensions, heat, and brightness as our present sun, but difiering from him in this, that it will have no rotation. We supposed the two globes to have been at rest when they were let fall from a mutual distance equal to the diameter of the earth's orbit. Suppose, now, that instead of having been at rest they had been moving in opposite directions with a velocity of two (more exactly 1'89) metres per second. The moment of momentum of these motions round an axis through the centre of gravity of the two globes perpendicular to their lines of motion is just equal to the moment of momentum of the sun's rotation round his axis. It is an elementary and easily proved law of dynamics that no mutual action between parts of a group of bodies, or of a single body, rigid, flexible, or fluid, can alter the moment of momentum of the whole. The transverse velocity in the case we are now supposing is so small that none of the main features of the collision and of the wild oscillations following it, which we have been considering, or of the magnitude, heat, and brightness of the resulting star, will be sensibly altered ; but now, instead of being rotationless, it will be revolving once round in twenty-five days and so in all respects like to our sun. If instead of being at rest initially, or moving with the small transverse velocities we have been considering, each globe had a transverse velocity of three-quarters (or anything more than • 71) of a kilometre per second, they would just escape collision, and would revolve in ellipses round the centre of inertia in a period of one year, just grazing each other's sui'face every time they came to the nearest points of their orbits. If the initial transverse velocity of each globe be less than, but not much less than, '71 of a kilometre per second, there will be a violent grazing collision, and two bright suns, solid globes bathed in flaming fluid, will come into existence in the course of a few hours, and will commence revolving round their common centre of inertia in long elliptic orbits in a period of a little less than a year. Tidal interaction between them will diminish the eccentricities of their 16 Sir William Thomson [Jan. 21, orbits, and if continued long enough will cause the two to revolve in circular orbits round their centre of inertia with a distance between their surfaces equal to 6 * 44 diameters of each. Suppose now, still choosing a particular case to fix the ideas, that twenty-nine million cold solid globes, each of about the same mass as the moon, and amounting in all to a total mass equal to the sun's, are scattered as uniformly as possible on a spherical surface of radius equal to one hundred times the radius of the earth's orbit, and that they are left absolutely at rest in that position. They will all com- mence falling towards the centre of the sphere, and will meet there in two hundred and fifty years, and every one of the twenty-nine million globes will then, in the course of half an hour, be melted, and raised to a temperature of a few hundred thousand or a million degrees Centigrade. The fluid mass thus formed will, by this pro- digious heat, be exploded outwards in vapour or gas all round. Its boundary will reach to a distance considerably less than one hundred times the radius of the earth's orbit on first flying out to its extreme limit. A diminishing series of out and in oscillations will follow, and the incandescent globe thus contracting and expanding alternately, in the course it may be of three or four hundred years, will settle to a radius of forty* times the radius of the earth's orbit. The average density of the gaseous nebula thus formed would be (215 x 40)~^, or one six hundred and thirty-six thousand millionth of the sun's mean density ; or one four hundred and fifty-four thousand millionth of the density of water ; or one five hundred and seventy millionth of that of common air at an ordinary temperature of 10° C. The density in its central regions, sensibly uniform through several million kilometres, is (see note on p. 11) one twenty thousand millionth of that of water ; or one twenty-five millionth of that of air. This exceedingly small density is nearly six times the density of the oxygen and nitrogen left in some of the receivers exhausted by Bottomley in his experimental measurements of the amount of heat emitted by pure radiation from highly heated bodies. If the substance were oxygen, or nitrogen, or other gas or mixture of gases simple or compound, of specific density equal to the specific density of our air, the central temperature would be 51,200° Cent., and the average translational velocity of the molecules 6*66 kilo- metres per second, being Vt ^^ 10*2, the velocity acquired by a heavy body falling unresisted from the outer boundary (of 40 times the radius of the earth's orbit) to the centre of the nebulous mass. The gaseous nebula thus constituted would in the course of a few million years, by constantly radiating out heat, shrink to the size of our present sun, when it would have exactly the same heating and lighting efficiency. But no motion of rotation. * The radius of a steady globular gaseous nebula of any homogeneous gas is 40 per cent, of the radius of the spherical surface from which its ingredients must fall to their actual positions in the nebula to have the same kinetic energy as the nebula has. 1887.] on the Sim's Heat. 17 The moment of momentum of the whole solar system is about eighteen times that of the sun's rotation ; seventeen-eighteenths being Jupiter's and one-eighteenth the Sun's, the other bodies being not worth taking into account in the reckoning of moment of momentum. Now instead of being absolutely at rest in the beginning, let the twenty-nine million moons be given each with some small motion, making ujd in all an amount of moment of momentum about a certain axis, equal to the moment of momentum of the solar system which we have just been considering ; or considerably greater than this, to allow for effect of resisting medium. They will fall together for two hundred and fifty years, and though not meeting precisely in the centre as in the first supposed case of no primitive motion, they will, two hundred and fifty years from the beginning, be so crowded together that there will be myriads of collisions, and almost every one of the twenty-nine million globes will be melted and driven into vapour by the heat of these collisions. The vapour or gas thus generated will fly outwards, and after several hundreds or thousands of years of outward and inward oscillatory motion, may settle into an oblate rotating nebula extending its equatorial ra- dius far beyond the orbit of Neptune, and with moment of momentum equal to or exceeding the moment of momentum of the solar system. This is just the beginning postulated by Laj)lace for his nebular theory of the evolution of the solar system ; which, founded on the natural history of the stellar universe, as ob- served by the elder Herschell, and completed in details by the profound dynamical judgment and imaginative genius of Laplace, seems converted by thermodynamics into a necessary truth, if we make no other uncertain assumption than that the materials at present constituting the dead matter of the solar system have existed under the laws of dead matter for a hundred million years. Thus there may in reality be nothing more of mystery or of difficulty in the automatic progress of the solar system from cold matter diffused through space, to its present manifest order and beauty, lighted and warmed by its brilliant sun, than there is in the winding up of a clock* and letting it go till it stops. I need scarcely say that the beginning and the maintenance of life on the earth is absolutely and infinitely beyond the range of all soimd speculation in dynamical science. The only contribution of dynamics to theoretical biology is absolute negation of automatic commencement or automatic maintenance of life. I shall only say in conclusion : — Assuming the sun's mass to be composed of materials which were far asunder before it was hot, the immediate antecedent to its incandescence must have been either two bodies with details differing only in proportions and densities from * Even in tins, and all the properties of matter which it involves, there is enough, and more than enough, of mystery to our limited understanding. A watch-spring is much farther beyond our understanding than is a gaseous nebula. Vol. XII. (No. 81.) c 18 Sir WiUiam Thomson [Jan. 21, tlie cases we have been now considering as examples; or it must have been some number more than two — some finite number — at the most the number of atoms in the sun's present mass, a finite number (which may probably enough be something between 4 x 10^'^ and 140 x 10^^) as easily understood and imagined as number 4 or 140. The immediate antecedent to incandescence may have been the whole constituents in the extreme condition of subdivision — that is to say, in the condition of separate atoms ; or it may have been any smaller number of groups of atoms making minute crystals or groups of crystals — snow-flakes of matter, as it were ; or it may have been lumps of matter like a macadamising stone ; or like this stone* (Fig. 1), which you might mistake for a macadamising Fig. 1. , 5 centimetres . stone, and which was actually travelling through space till it fell on the earth at Possil, in the neighbourhood of Glasgow, on April 5, 1804 ; or like that * (Fig. 2) which was found in the Desert of Atacama, in South America, and is believed to have fallen there from the sky — a fragment made up of iron and stone, which * These three meteorites are in the possession of the Hunterian Museum of the University of Glasgow, and the woodcuts, Figs. 1, 2, and 3, have been executed from the actual specimens kindly lent for that purpose by the keeper of the museum, Professor Young. The specimen represented by Fig. 1 is contained in the Hunterian collection, that by Fig. 2 in the Eck collection, and that by Fig. 3 in the Lanfine collection — the scale of dimensions is shown for each. It may be remarked that Fig. 2 represents a section of the meteorite taken in the plane of the longest rectangular axes; the bright markings being large and well-formed crystals of olivine, embedded in a matrix of iron. In Fig. 3 is depicted the beautiful Widmanstatten marking characteristic of all meteoric iron, and so well shown in the well-known Lenarto meteorite. 1887.] on the Suns Heat. 19 looks as if it has solidified from a mixture of gravel and melted iron ma place where there was very little of heaviness oTtht splendidly crystallised piece of iro^n (Fig. 3), a slab ' cu ou c 2 20 Sir William Thomson [Jan. 21, of the celebrated aerolite which fell at Lenarto, in Hungary ; * or this wonderfully-shapsd specimen (of which two views are given Fig. 4. in Figs. 4 and 5), a model of the Middlesburgh meteorite (kindly given me by Professor A. S. Herschel), having corrugations showing * See footnote, p. 18. 1887.] on the Sun's Heat, 21 how its melted matter has been scoured off from the front part of its surface in its final rush through the earth's atmosphere when it was seen to fall on March 14, 1881, at 3.35 p.m. For the theory of the sun it is indifferent which of these varieties of configurations of matter may have been the immediate antecedent of his incandescence, but I can never think of these material ante- cedents without remembering a question put to me thirty years ago by the late Bishop Ewing, Bishop of Argyll and the Isles : " Do you imagine that piece of matter to have been as it is from the beginning ; to have been created as it is, or to have been as it is through all time till it fell on the earth ? " I had told him that I believed the sun to be built up of meteoric stones, but he would not be satisfied till he knew or could imagine, what kind of stones. I could not but agree with him in feeling it impossible to imagine that any one of such meteo- rites as those now before you has been as it is through all time, or that the materials of the sun were like this for all time before they came together and became hot. Surely this stone has an eventful history, but I shall not tax your patience by trying just now to trace it conjecturally. I shall only say that we cannot but agree with the common opinion which regards meteorites as fragments broken from larger masses, and we cannot be satisfied without trying to imagine what were the antecedents of those masses. [W. T.] 22 Professor W. Baldivin Spencer [Jan. 28, WEEKLY EVENING MEETING, Friday, January 28, 1887. Sir John Lubbock, Bart. M.P. D.C.L. LL.D. F.R.S. Vice-President, in the Chair. Professor W. Baldwin Spencer. TJie Pineal Eye in Lizards. There is present in the human brain, buried deeply beneath the surface and hence concealed from view externally, a small blunt process : it differs in nature from the surrounding nervous matter, being hard to the touch. To this small process human anatomists gave the name of pineal gland, and its meaning has always remained a problem. Investigation of the brains of other animals showed that in these the structure was present : in fact it is typical of the brains of all true vertebrata, and not only this, the lower we descend in the scale of vertebrate life, the more highly developed does it become in comparison to the remaining parts of the brain. In such a mammal as a rabbit it is, for example, larger than in man ; in a bird it is still more highly developed ; whilst when we come down to fishes, the pineal gland or epiphysis, as it is better called, assumes the form of a forwardly directed hollow process whose distal extremity is swollen out into a vesicle, the proximal part forming a hollow stalk running back to the roof of the brain. If the brain of a lizard, such as Hatteria, be examined, the epiphysis is seen to have undergone a very definite change : it is divided more clearly than in other animals into the two divisions above mentioned ; sections, however, show that the stalk is solid and that the vesicle has become developed into an organ of vision — into a pineal eye. This is the highest stage of development reached by the epii)hysis, and is now preserved, so far as is at present known, in lizards only amongst living animals. Turning to the development of the brain : it is seen in early stages in all vertebrates to have the form of a simple tube running the whole length of the back of the animal ; a little later the walls of the anterior division have bulged out and given rise to three vesicles which are known as the fore, mid, and hind brains; the part of the tube posterior to these forms the spinal cord. As development proceeds, from the fore brain on either side is given off a hollow process, each one of which forms an optic vesicle, and at the same time there grow forward two outgrowths of the fore brain which give rise to the cerebral hemispheres ; in addition to these structures, the roof of the fore brain gives off a single median outgrowth which grows forward within the skull cavity, swelling out distally into a small 1887.J on the Lineal Eye in Lizards 23 vesicle : in the skull wall itself in most lizards there is present a distinctly marked hole, and in this, which is called the parietal foramen lies the small vesicle. Changes take place in the walls of the optic vesicles which transform them into the sensory parts of the paired eyes, whilst the small vesicle formed out of the dorsal outgrowth of the brain, or epiphysis, becomes formed into the single pineal eye. Thus from the walls of the fore brain are developed in lizards three eyes — a single median and two paired ones. Digressing for a moment, it is interesting to notice that this is by no means the only example of a single median eye which is known in the animal kingdom. Almost every people has its myth of a median- eyed race of men, who may, as in the Grecian Cyclops, be represented with the single eye, or with this in addition to the paired eyes : it is curious also to find that Buddha and Siva are represented with median eyes : whilst to such an extent is this idea carried, that even the Nautch girl paints on her forehead the outline of a single median eye. Leaving the mythical we come to animals in which such a structure is actually present: in the class Crustacea we meet with many examples of this ; first in the little fresh-water Cycloj^s and all its allies, there is only the one solitary eye, the presence of which has gained for it its name. In other Crustacea again we find that the animal on leaving the egg-cascwhas a very definite form, quite unlike that of the adult : it is, amongst other things, always provided with three, and no more or less than three pairs of a2)pendages by means of which it moves about ; it has in addition always a single median eye which, inasmuch as the animal in this stage is called a uauplius, is known as the nauplius eye. As development goes on, there appear two eyes, one at either side of the original one : in some cases the latter may disapj^ear, in others it may be retained, though the lateral paired eyes always become larger than the single one, and thus, though there is no real connection between the two whatever, we find in Crustacea a mCLlian and two paired eyes present just as in lizards. Turning to the latter, we find the epiphysis, as before said, more highly developed than in any other living animal. The distal vesicular expansion is present in many forms, but here only is it transformed into an eye and connected with the brain by a solid pineal stalk developed from the proximal part of the epiphysis and serving doubtless as an optic nerve. If the head of a lizard, such as an Iguana or Calotes, be examined, there is seen on the middle line dorsally, and somewhat behind the level of the paired eyes, a peculiarly modified scale ; it bears a circular space, which may be raised into a dome-shape, or may be merely surrounded by a raised rim, but is always noticeable by its whiteness, this being due to an absence of pigment in the skin of this par- ticular spot. The modified scale indicates the position of the pineal eye lying beneath, and thus of the parietal foramen enclosing the eye : it does not necessarily follow that no eye is present, because 24 Professor W. Baldwin Silencer [Jan. 28, there is no special external indication, nor, on the other hand, does the presence of the latter indicate infallibly a well-developed eye. Thus in Hatteria, the New Zealand lizard, there is no external indication of the eye, save perhaps a slight absence of pigment in the skin immediately above the parietal foramen ; but if longitudinal vertical sections be cut through the head, the eye is found lying deeply embedded in connective tissue within the foramen. It has the form somewhat of a cone, whose base is directed forwards and upwards, whilst the apex points backwards and is united with the pineal stalk. The base of the cone is formed by the lens, which consists of elongate, nucleated cells, arranged so as to form a cone whose apex points inwards and lies in the line of the optic axis ; the lens is directly continuous with the retina, and thus, unlike that of the paired eyes, is formed directly out of what was originally part of the brain- wall. The retina itself is well developed in Hatteria, and forms a strong contrast to that of the lateral eyes, inasmuch as the rods, em- bedded in dark-brown i3igment, face inwards and line the cavity of the vesicle, whilst in the paired eye, the same structures are on the side of the retina remote from the cavity of the eye in the adult, though this, it must be remembered, is not homologous with the cavity in the pineal eye. External to the rods lies first a layer of spherical, nucleated elements, then a molecular layer consisting of finely punctated material, then another layer of spherical elements, followed by a layer of cone and spindle-shaped structures, which again lie clirectly upon a thin layer of nerve-fibres spreading out from the pineal stalk. The rods lying in the optic axis are much elongated and very prominent, a feature common to all eyes which are still in connection with the optic stalk. This may be taken as a description of the retina of a typical j)ineal eye, though it is more highly developed in Hatteria than in many other lizards at the present day. The remainder of the ejiij^hysis may be divided into two parts, a solid pineal stalk nearest the eye, and a hollow part running back to the roof of the brain and overlying, as it nears the latter, the vascular roof of the third ventricle. In many lizards degeneration seems to have set in and the eye to have become more rudimentary than it is in Hatteria ; in fact, in the latter, the only sign of its rudimentary nature is its position deeply buried in the connective tissue within the parietal foramen, a position which must prevent its functioning as an organ of vision at the present time. If we take such a lizard as Varanus hengalensis, sections through the parietal foramen show that the eye is well developed and placed not far below the surface of the head, whilst between it and the latter is a marked absence of the pigment cells which form so prominent a feature in sections of the skin all around. Further examination however reveals an important point of difference when compared with Hatteria — the eye has lost its connection with the proximal part of the cprphijsis, which has the form of a hollow process 1887.] on the Pineal Eye in Lizards. 25 running forwards from the roof of the brain within the skull till it reaches the parietal foramen ; but the distal vesicle, transformed into an eye, has become completely separated off from it. This again may be taken as an example of a large number of lizards, including such forms as Varanus hengalensis, Anguis fragUis, Seps chalciclica and Calotes opMomaca. In other forms, still further de- generation seems to have taken place, or, to speak more correctly, the epijDhysis appears to develop to a certain point, but never, at the present time, to reach the stage at which it becomes transformed into an eye. If the brain of Cydodiis gigas be examined, the epiphysis when cut in section has merely the form of a hollow dorsal process running forward from the brain till it reaches the parietal foramen ; within this it expands to form a vesicle, but apparently development stops at this, which must necessarily be a stage passed through in the formation of every pineal eye. The pineal stalk never becomes solid, nor do the walls of the vesicular enlargement become modified into lens and retina, though there is a slight difference to be noticed between the anterior and posterior walls, indicating perhaps the earliest of the series of changes, whereby out of the former is pro- duced the lens, and out of the latter the rods and external-lying elements of the retina. These three examples — Hatferia, Varamis, and Cijclodus — will serve to illustrate the more important stages of development met with at the present time in the epiphysis of lizards. We may now turn for a minute or two to the consideration of the question, whether it is possible to connect this single median eye with any structure in lower forms, whether the latter, in fact, possess any organ out of which we may suppose the epiphysis of higher forms to have been gradually evolved. Amongst the lowest forms of Vertebrata known to us— the Tunicata — we find that at one stage of their de- velopment they possess a dorsal nerve-cord, whose anterior end becomes swollen out and thus forms what we may call a brain ; in fact this homology with the same part in higher forms is further strengthened by its relationshij) to tlie anterior end of the notochord which, running the whole length beneath the j)osterior part of the nerve-cord, stops just before reaching this anterior swollen extremity. In the adult of most forms of Tunicata the latter is the only j)ersistent portion of the whole nervous system, and its development alone enables us to homologise it with the brain of such an animal as a lizard. Now if this Tunicate brain be examined it is found to possess a single eye placed not quite but nearly in the median line, hut com- pletely ivithin the brain cavity. The Tunicata are, individually, small and transparent, and thus the light can as easily affect an internal as an externally-placed eye. The question naturally arises, suj^posing the Tunicata to have developed from some ancestor common to them and the higher Vertebrata, has this single eye anything to do with the pineal eye ? The latter cannot be directly developed out of the 26 Professor W. Baldwin S})encer [Jan. 28, former, that is, there must have been a stage passed through in which the internal eye of the Tunicate-like ancestor was undergoing evagination, and during which period it could not function as an organ of vision, but it is possible that the internal eye of the small, transparent form became changed into the externally-placed epiphysis of the larger and more oj)acLue animal which was gradually evolved out of the Tunicate-like ancestor. By fui-ther and secondary modification the epij)hysis gave rise to a distal vesicle and a proximal pineal stalk, whilst still later again the former became modified into the pineal eye. Henri de Graaf in his memoir on the development of the epiphysis, mentions as a curious fact in its formation in Bufo cinerea, that it originates as a thickening of the brain roof and that there is a small mass of pigment present for some little time at the inner ends of the cells forming the thickening ; now this is exactly the development, according to Kowalevsky, which is passed through in early stages during the formation of the eye of a larval Tunicate ; in the latter the eye comes subsequently to lie within the brain, still more pigment being developed and a lens formed, whilst in Bufo the pigment dis- appears, the thickening forms into an evagination, and the e2)iphysis, as present in all higher Vcrtebrata, is gradually formed. It is quite possible, however, that this may present us with some of the steps passed through in the gradual development of the epiphysis out of the internally placed eye of the Tunicate-like ancestors of living Vertebrata. We may perhaps go even a step further and find in these low vertebrate forms the structures which by a similar evagination have given rise to the optic vesicles out of which by a later modifica- tion were developed the paired eyes. In one form of Tunicata — the galps — are found in the brain (that is the persistent anterior ex- tremity of the larval nerve-cord), not one, but three eyes, of which one is median and two are lateral ; we may perhaps be here presented with the organs which have gradually given rise, during the change from a transparent to an opaque animal, to the three vesicles which in all Vertebrata, save the Tuiiicata and Amphioxus, now form the single dorsal epiphysis and the paired, lateral, optic vesicles. At the present time the median pineal eye is found only in lizards, and even here it is but in a rudimentary condition ; it is always intimately associated with the presence of the parietal foramen ; if the foramen be present the eye is found in a more or less highly developed state, if the foramen be wanting the eye is absent. It is curious to note that the foramen is a marked characteristic of extinct forms of vertebrate life — of the Labyrinthodonts of Palaeozoic, and the Saurians of Mesozoic times ; so far as can be told it is simply formed to allow the distal extremity of the ei^iphysis to pass through the skull roof, and thus to enable the pineal eye to be placed upon the surface of the head. We are probably right in assuming that the eye was most largely developed in these extinct forms, and thus it is 1887.] on the Pineal Eye in Lizards. 27 peculiarly interesting to note that at the present day it is found most highly developed in Hatteria, which, sheltered from competition of surrounding forms in its island home in New Zealand, has retained this, amongst other archaic features, pointing to its close alliance with the extinct reptilian fauna of Mesozoic times. [W. B. S.] 28 Mr. E. Freshjield [Feb. 4, WEEKLY EVENING MEETING, FricLay, February 4, 1887. Henry Pollock, Esq. Treasurer and Vice-President, in the Chair. Edwin Freshfield, Esq. LL.D. V.P.S.A. Some TJiifuhlislied Records of the City of London. In the records of the 113 parishes within the City of London, and the 17 out-parishes, there are materials for a parochial and social history unrivalled in the world. These records which, commencing with the 15th century, extend to the present time in a more or less comj)lete state, consist of books of records, vestry minutes, and account books and registers. These books contain lists of the parish property, sanitary orders made by the various parishes, their regulations for self-government, and evidences of the great destruction of valuable works of art which took place in King Edward VI.'s reign, at the Reformation. The particular books from which extracts have been selected, are those of St. Margaret's, Lothbury, St. Stephen's, Coleman Street, St. Bartholomew by the Exchange, and St. Christopher-le-Stocks. The minutes of the vestries describe accurately the relations of the clergy to the parishioners during the sixteenth and early part of the seventeenth century, the causes which led to the complete break between the clergy and laity which took place at the commencement of the Great Eebellion in 1642. These also show the working of the sanitary arrangements during the same period, particularly those having reference to the various epidemics of the plague. That which is in some respects the most interesting portion of these books, is the history of the Great Eebellion, the Commonwealth, the Pro- tectorate, and the Restoration. In order to illustrate this, the history of the parish of St. Bartholomew by the Exchange, as displayed in the parish books, has been supplemented by extracts from the books of the adjoining parishes during a corresponding period. At the outbreak of the Great Eebellion, the rector of St. Bar- tholomew's— Dr. Grant — was an easy-going Chm-chman, who had rendered himself liable to sequestration for refusing to sign the " solemn league and covenant." The parishioners, numbering among them Sir Harbottle Grimstone, Mr. Justice Peter Pheasant, and Dr. Zouch, came to an arrangement with him — which is embodied in the vestry minutes — whereby, in exchange for a pension, he sur- rendered the parsonage house, and the right to officiate in the church during his life, conferring the right of nominating a locum tenens upon the parishioners. This right they exercised from the year 1644 until Dr. Grant's death in 1658. During this period, the living was held 1887.] on UnpuhlisJied Records of London. 29 first by Dr. Lightfoot (a Presbyterian), the celebrated Eabbiuical scholar, afterwards by Mr. Cawton, another Presbyterian, who was imprisoned for praying for King Charles II. after the execution of his father, and finally had to leave the country in consequence of his association with Mr. Love, the rector of St. Ann and St. Agnes, who was executed on Tower Hill for negotiating with the Scotch for bringing King Charles II. to England. During the incumbency of Dr. Lightfoot and Mr. Cawton, the Presbyterian Church government was in full force in the parish, and the nature of it, and the dissatisfac- tion which it caused to the inhabitants, is clear from the parish books. After Mr. Cawton's flight to Holland, the parishioners appointed another Presbyterian named Mr. Hall, who continued until the death of Dr. Grant. In 1653, the living then being vacant, and in the gift of the Commissioners of the Great Seal, they appointed one Sidrach Simpson, a well-known Indej)endent. He died about eighteen months after his appointment, having in the meantime been suspended and imi)risoned by the Protector Oliver, in consequence of his having preached against his personal government. On Mr. Sidrach Simpson's death, the Protector aj)pointed — without consulting the Commissioners of the Great Seal— by a writing under his own hand, to the living one of his chaplains, Mr. Philip Nye, who associated with him another Independent minister named Mr. John Loder. The minutes from this time to the months immediately preceding the Eestoration, give an interesting account of the quarrels between Mr. Nye and Mr. Loder and the parishioners, on the ground that they refused to administer the sacrament and to christen children, except the parishioners would be joined in communion with their Church, the parishioners also refusing to pay tithes, on the ground that their church was taken up and their pews filled with strange congregations. Mr. Loder, on behalf of Mr. Nye, offered the parishioners to allow them to choose a minister to officiate in the afternoons of the Lord's Day in a manner which was adopted in the adjoining parish of St. Stephen's, Coleman Street, where Mr. John Godwin, the Independent, shared the church with Mr. John Taylor, the Presbyterian vicar, but this the parishioners of St. Bartholomew's refused. In January 1659 the Lord General Monk came to London, and on his demand the secluded members were reinstated in the resuscitated Long Parliament, then sitting, and fresh Commissioners of the Great Seal were appointed. The parishioners took the opportunity to petition the Com- missioners to declare the living vacant on the ground that the Pro- tector Oliver had improperly presented to the living which was in their gift. The books show how Mr. Loder had obtained from the Lord General Monk a letter to the Commissioners in his favour, which letter the Lord General at a subsequent request of the parishioners revoked, and how the Commissioners refused to appoint any of the Independent faction and ultimately appointed Dr. Brideoak, one of the defenders of Lathom House and a friend of the Speaker 30 Mr. E. Freshfield on Unpublished Becords of London. [Feb. 4, Lenthall. They illustrate the state of affairs and the Lord General's own condition of micd at this particular juncture, viz. in the months of March and April 1659-60. In March he had not yet broken with the Independent faction and thrown in his lot with the Royalists. It was probably at this time that the first letter in favour of Mr. Loder was written. The letter revoking the first letter was no doubt written at the time when the Lord General had de- termined to throw in his lot with the Royalists. In a minute of the same vestry in September 1659, the churchwarden mentions an application to the Grocers' Company to take the balance of the parish stock upon interest and the fact that the Grocers' Company would not pay him more than 5 per cent, interest, the minute concluding " that in regard to the existing great hazard and danger of the times by reason of public differences and decay of trade in general, the money aforesaid, viz. 150/., was paid into the hands of the Grocers at 5 per cent." The lively interest taken in parochial matters by Speakers of the House of Commons, Masters of the Rolls, lawyers, merchants, and people holding high Government appointments, is apparent from these books and compared favourably with the present apathy. They also illustrate the extraordinary personal nature of the Protector's government during the Protectorate, and the important part played by the City of London at this time, the reason why the citizens threw in their lot with the Parliament, why they afterwards joined in the restoration of the King and the Church, which was as plainly written as if you could converse with the people who had written the minutes. [E. F.] 1887.] General Monthly Meeting. 31 GENEEAL MONTHLY MEETING, Monday, February 7, 1887. Henry Pollock, Esq. Treasurer and Vice-President, in the Chair. Gustav Bischof, Esq. F.C.S. James Frederick Burton, Esq. G. Donaldson, Esq. Harry Montague Elder, Esq. B.A. Eev. Alfred William Momerie, D.D. Mrs. Bloomfield Moore, John Alexander Radcliffe, Esq. were elected Members of the Royal Institution. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FKOM The Lords of the Admiralty — Nautical Almanac for 1890. 8vo. 1886. Accademia dei Lincei, Beale, Roma — Atti, Serie Quarta : Kendiconti. Vol. II. 2" Semestre, Fasc. 8, 9, 10, 11. 8vo. 1886. American Academy of Arts and Sciences — Memoirs, Vol. XI. Part 4, No. 4. 4to 1886. Proceedings, Vol. XXI. Part 2. 8to. 1886. American Fhilosophiccd Society — Proceedings, No. 123. 8vo. 1886. Asiatic Society, Boyal — Journal, Vol. XIX. Part 1. 8vo. 1887. Astronomiccd Society, Eoyal — Monthly Notices, Vol. XLVII. Nos. 1, 2. 8vo. 1886. Bankers, Institute of— 3om^a\,No\.\ll.V^rtQ; Vol. VIII. Part 1. 8vo. 1886. Bavarian Academy of Sciences, Boyal — Abhandlungen, Band XV. Abtheilung 3. 4to. 1886. Birliett, John, Esq. F.R.C.S. M.R.L— The Irish Question. By T. E. Webb. 8vo. 1886. Facts and Fictions in Irish History. By Lord Brabourne. 4to. 1886. Boston Society of Natural History — Memoirs, Vol. III. Nos. 12, 13. 4to. 1886. Proceedings, Vol. XXIII. Part 2. 8vo. 1886. British Architects, Boycd Institide of — Proceedings, 1886-7, Nos. 4, 5, 6, 7. 4to. Cambridge Phdosophical Society — Proceedings, Vol. V. Part 6. 8vo. 1886, Chemical Society — Journal for Dec. 1886, Jan. 1887. 8vo. Chile, Officina Central Meteorolojica — Annuario, 1886. 8vo. Nos. 3, 4. Co7igregational Library— Co-talogue. 8vo. 1886. Crisp, Frank, Esq. LL.B. F.L.S. &c. M.B.I, (the Editor)— Journal of the Royal Microscopical Society, Series II. Vol. VI. Part 6. 8vo. 1886. Dax : Societe de Borda — Bulletins, 2^ Serie, Onzieme Annee, 4® Trimestre. 8vo 1886. East India Association— Journal, Vol. XIX. No. 1, 8vo. 1887. Editors — American Journal of Science for December 1886, January 1887. 8vo. Analyst for December 1886, January 1887. 8vo. Athenaeum for December 1886, January 1887. 4to. Chemical News for December 1886, January 1887. 4to. Chemist and Druggist for December 1886, January 1887. 8vo. Engineer for December 1886, January 1887. fol. Engineering for December 1886, January 1887. fol. Horological Journal for December 1886, January 1887. 8vo. 32 General Monthly Meeting. [Feb. 7, Industries for December 188G, January 1887. fol. Iron for December 1886, January 1887. 4to. Nature for December 1886, January 1887. 4to. Revue Scientifique for December 1886, January 1887. 4to. Telegraphic Journal for December 1886, January 1887. 8vo. Zoophilist for December 1886, January 1887. 4to. Florence, Bihlioteca Nazionale Ce»^raZe— Bolletino, Num. 22, 25. 8vo. 1886. Franklin Institute— Jouvnah Nos. 732, 733. 8vo. 1886. General Medical Council — Third Report of Statistical Committee. 8vo. 1886. Geographical Society, Boyal — Proceedings, New Series, Vol. VIII. No. 12 ; Vol. IX. No. 1. 8vo. 1886-7. Johns HopMns University— Studies in Historical and Political Science, Fourth Series, Nos. 11, 12; Fifth Series, Nos. 1,2. 8vo. 1886-7. University Circular, Nos. 53, 54. 4to. 1886. American Chemical Journal, Vol. VIII. No. 6. 8vo. 1886. American Journal of Philology, No. 27. 8vo. 1886. Kew Ohservatory — Report, 1886. 8vo. Klein, Sydney T. Esq. F.R.A.S. {the Author) — Hunting among the Lepidoptera and Hymenoptera of Middlesex. 8vo. 1887. Lawrence, Edwin, Esq. M.R.I, (the Aidhor) — The Progress of a Century. 4to. 1886. Manchester Geological Society— TrdnssLctions, Vol. XIX. Part 2. 8vo. 1887. Mechanical Engineers' Institution — Proceedings, 1886, Nos. 3, 4. 8vo. Medical and Chirurgioal Society, Royal — Proceedings, New Series, No. 14. 8vo. 1886. Menshrugghe, M. G. Van der (the Author) — L'Instabilite de Pequilibre de la Couche Superficielle d'un Liquide. Partie 1% 2^. 8vo. 1886. Meteorological 0^'ce— Hourly Readings, 1884, Part 1. 4to. 1886. Ministry of Public Worhs, J?o>ne— Giornale del Genio Civile, Serie Quarta, Vol. VI. No. 9. 8vo. And Disegni. fol. 1886. Murray, John, Esq. (the Editor)— Muvmy's Magazine, No. 1. 8vo. 1887. Numismatic Soeiety-Chromcle and Journal, 1886, Part 3. 8vo. Odontological Society of Great Britain — Transactions, Vol. XIX. No. 2. New Series. 8vo. 1886. Pennsylvania, Second Geological Survey of — Annual Report, 1885. With Atlas. 8vo. 1886. Pharmaceidical Society of Great Britain — Journal, Dec. 18S6, Jan. 1887. 8vo. Photograpjhic Society— J onrna]. New Series, Vol. XI. Nos. 2, 3. 8vo. 1886. Prince, C. Leeson, Esq. (the Author) — The Climate of Uckfield, Sussex, and its Neighbourhood, 1843-1870. 2nd edition. 8vo. 1886. Richardson, B. W. M.D. F.R.S. (the Author)— The Asclepiad, Vol. IV. No. 13. 8vo. 1887. Royal Society of Canada — Proceedings and Transactions, Vol, III. 4to. 1886. Royal Society of London— Vvoceedings, Nos. 247, 248, 249. 8vo. 1886. Sanitary Institute of Great Britain — Transactions, Vol. VII. 8vo. 1886. Society of Jr^s— Journal, Dec. 1886, Jan. 1887. 8vo. Essays on the Street Re-alignment, Reconstruction, and Sanitation of Central London. (Westgarth Essays.) 8vo. 1886. St. Petershourg, Academic des Sciences — Memoires, Tome XXXIV. Nos. 5, 6. 4to. 1886. Bulletin, Tome XXXI. No. 3. 4to. 1886. United Service Institution, Royal — Journal, No. 137. 8vo. 1886. United States Geological Survey — Bulletins, Nos. 27-29. 8vo. 1886. University of London — Accessions to the Library, 1876-1886. 8vo. 1886. Vereins zur Beforderung des Geiverhfleisses in Preussen — Verhandlungen, 1886 : Heft 9, 10. 4to. Victoria Institute — Journal, No. 79. Svo. 1886. 1887.] Mr, Edward B. Puulton on Gilded Chrysalides. 33 WEEKLY EVENING MEETING, Friday, February 11, 1887. SiE William Bowman, Bart. LL.D. F.E.S. Manager and Vice-President, in the Chair. Edward B. Poultox, Esq., M.A. Gilded Chrysalides. Previous Work — Mr. T. W. Wood in 1867 published the obser- vation that certain pupae (Pieris hrassicse, P. rajpse, kc) resemble in oolour the surface on which they are found. Although this was disputed by some naturalists, it was confirmed by Mr. A. G. Butler and Prof. Meldola. In 1874 Mrs. M. E. Barber published some very striking observations on the colours of the pupa of Papilio nireus (South Africa) confirmation being afterwards afforded by Mr. Trimen, from the case of Papilio dernoleus. Dr. Fritz Muller, however, shows that Papilio polydamus is not sensitive to surrounding colours. The observations were explained by supposing the moist skin of the freshly formed pupa to be " photographically sensitive " to the colour of surrounding surfaces ; but Prof. Meldola pointed out that there can be no real analogy with photography. Furthermore, many pupae are formed at night when the surrounding surfaces are dark. The present investigation was undertaken with the belief that the influence would be found to work upon the larva as it rests upon some coloured surface before pupation. I. Experiments upon Vanessa lo. — This pupa appears in two varie- ties, being commonly dark grey and much more rarely yellowish-green. Six larvae placed in a glass cylinder covered with green tissue paper, produced six green pupae ; one of these transferred to a black surface while still moist and fresh, became a green pupa precisely like the others. II. Experiments upon Vanessa urticse. — The pupae have no green form, but appear in many shades of dark grey, the lighter ones having golden spots on them, while the extreme forms are almost covered with the golden appearance. These latter are very rarely seen in nature, except when the pupa is diseased. Over 700 pupae were obtained in the following experiments : — 1. Effects of Colours. — Gh-een and orange surroundings caused no effect on the pupal colours ; hlach produced, as a rule, dark pupae ; u'hite produced light pupae, many of them being brilliantly golden. This last result suggested the use of gilt surroundings, which were found to be more efficient than white, and produced pupae with a colour which even more resembled gold. 2. Mutual Proximity. — The larvae being dark, it was found that when many of them became pupte on a limited (white or gilt) area, the Vol. XIL (No. 81.) d 34 Mr, Edward B. Poulton [Feb. 11, pupae were darker than wlien they had been more isolated. The colours of each were in fact affected by that part of the surroundings made up by the black skins of its neighbours. 3. Illumination. — Black surroundings produced rather stronger effects in darkness than in light, but the pupas were dark in both cases. 4. Time of Susceptibility. — The mature larvae, after ceasing to feed, wander (stage i.) until they find a surface on which to pupate ; they then rest upon it (stage ii.), and finally hang, head downwards, suspended by their last pair of claspers (stage iii.), in which position pupation takes place. Stage i. is variable in length, stage ii. may be estimated at 15 hours (but it is also variable), while stage iii. is fairly constant, and lasts about 18 hours ; while the whole period is commonly about 36 hours in length. The larvae are probably affected by surrounding colours for about 20 hours, before the last 12 hours of the whole period, and in this time the puj^al colours are determined. These facts were discovered by a very large number of experiments, in which larvae were placed in surroundings of one colour, and then after a variable time were transferred to another colour producing an opposite effect. It was thus found that stage ii. is more sensitive than stage iii., although there is some susceptibility during the latter stage. 6. The Part of the Larvse ivhich is Sensitive to Colour. (a) The Ocelli. — The most obvious suggestion was that the larval eyes (or ocelli, six on each side of the head) saw the colours, and being influenced, transmitted an impulse to the nervous centres wliich regulate the formation of the pupal colours. When, however, these organs were covered with black varnish, the pupae resembled sur- rounding surfaces to the same extent as when they were produced from normal larvae. (^) The Complex Branching Spines. — It seemed possible that these structures might contain some organ which was influenced by the colour, but after cutting them off, the larvae remained normally sensitive. (y) The General Surface of the Shin. — This was tested by conflicting colour experiments. It had been previously shown that the larvae were sensitive during stage iii., and therefore they were covered in this stage with compartmented tubes, so constructed that the head and anterior part of the body hung in the lower chamber of one wlour, while the posterior part of the body was in the upper chamber in another colour. In another method, the larvae were hung upon a vertical surface, while the head and front part of the body passed through a hole in a shelf, the vertical surface above the shelf, and the upper side of the shelf itself being one colour, while the vertical surface below the slielf and the lower side of the shelf were of the colour tending to produce the most opposite effects. The result of all these experiments was to show that the colour influence does act on some element of the larval skin, and tjjat the larger the area of skin 1887.] on Oilded Chrysalides. 35 exposed to any one colour the more does the pupa follow its influence. Particoloured pupae were not obtained, thus probably pointing towards the action of the nervous system rather than towards the direct action of light on or through the skin itself. 6. The Nature of the Effects produced. — The colouring matter of the dark pupae is contained in a thin superficial layer of the cuticle ; below this is a thicker layer divided into exceedingly delicate lamelljB between which fluids are present, and the latter form the thin plates which, by causing interference of light, produce the brilliant metallic appearance. The thinner upper layer being dark, acts as a screen in the dark pupae. Precisely the same metallic appearances are caused by the films of air between the thin plates of glass which are formed on the surface of bottles long exposed to earth and moisture. Both have the same spectroscopic characters and the same transmitted colours (complementary to those seen by reflection). The brilliancy of the cuticle can be preserved in spirit for any length of time; it disappears on drying, but can be renewed on wetting (this had been previously kno vn), and the colours are seen to change during the process of drying, and when the cuticle is pressed, for the films are thus made thinner. The same lamellated layer exists in non-metallic pupae, and is used as a reflector for transparent colouring matter contained in its outer lamellae. Thus the structure which rendered possible the brilliant effects due to interference, probably existed long before these special effects were obtained, and was used for a different purpose. 7. The Biological Value of the Gilded Appearance. — It is probable that the gilded pupee of Yanessidae resemble glittering minerals such as mica (which is very common in many places) ; their shape is very angu- lar, and like that of minerals : conversely the grey pupae resemble grey and weathered rock-surfaces, and the two conditions of rock would them- selves act as a stimulus for the production of pupae of corresponding colour. The power was probably gained in some dry hot country, where mineral surfaces do not weather q[uickly. Once formed it may be used for other purposes, and in certain species is probably a warning to the enemies that the insect is inedible. It is interesting to note how the Yanessidae, primarily coloured so as to resemble mineral surroundings, are modified for pupation on plants. Thus Vanessa lo has a green form which is produced among leaves ; V. atalanta has no green form, and spins together the leaves for concealment, bat both these species commonly pupate freely exposed on mineral surfaces ; V. urticse has neither the green form nor the habit, and it has a strong disinclination to pupate on its food-plant, as many observations concurred in proving. III. Experiments upon Vanessa atalanta. — This species was also made brilliantly golden or dark-coloured by the use of appropriate surroundings in the larval condition. lY. Experiments upon Papilio machaon. — This species, like P. poly- damiis (Fritz Miiller) has no power of being influenced by surroundinof colours. A brown pupa was obtained on the food-plant, and many D 2 ^6 Mr. Edward B. Poulton on Gilded Chrysalides. [Feb. 11, green ones upon brown twigs, &c. It is probable that less healthy and smaller larvae often produce the brown form, just as diseased Vanessa larvae produce gihled pup^. V. Experiments upon Pieris hrassicse and P. rapse. 1. Effects of Colours — Blach produced dark pupae, and the greater the illumination the darker the pupae (P. rapse), this result being the reverse of that obtained with V. urticse ; ivJiite jjroduced light i3up8e, and the greater the illumination the lighter the pup^ (P. Q-apse) ; dark red (P. hrassicse) produced dark pupae ; deep orange, in both species, produced very light pupae of a green colour ; pale yellow ^ndi yellowish- green produced rather darker pupae than the orange ; hluish-green pro- duced much darker pupae, while darh blue produced still darker pupae (P. rapse only). Hence there is a remarkable and sudden fall, followed by a slow and gradual rise in the amount of pigment formed as the light from various parts of the spectrum from red to blue pre- dominates in the reflected rays which fall on the larval surface. But their effects on the formation of superficially placed dark i>igment are accompanied by changes affecting the formation of greens and yellows, &c., in the deeper subcuticular tissues. Hence the results of any given stimulus are exceedingly complicated. 2. Oilier Experiments.— It was shown by the method described above that the ocelli are not sensitive in this species, and by similar transference experiments it was proved that the influence acts on the larva and not on the pupa itself. YI. Experiments upon Ephyra pendularia. — In this genus of moths the exposed pupae are often green and brown in different individuals, but these colours follow the corresponding tints of the larvae, and therefore cannot be influenced unless the latter themselves were changed, and such susceptibility in the larval state has not been proved for this genus. This is the only known instance of a constant relation between the larval and pupal colours. VII. Experiments upon the Cocoon of Saturnia carpini. — It was found that the larvae spin dark cocoons in black surroundings, but white ones in lighter surroundings. [E. B. P.] 1887,] Mr. W. Croolces on Genesis of the Elements. 37 WEEKLY EVENING MEETING, Friday, February 18, 1887. Sir Frederick Abel, C.B. D.C.L. F.E.S. Manager and Vice-President, in the Chair, William Crookes, Esq. F.R.S. V.P.C.S. M.BJ. Genesis of the Elements, In the very words selected to denote the subject I have the honour of bringing before you, I have raised a question which may be regarded as heretical. At the time when our modern conception of chemistry first dawned upon the scientific mind, the average chemist as a matter of course accepted the elements as ultimate facts. He regarded his elements as absolutely simple, incapable of transmutation or decom- position, each a kind of barrier behind which we could not penetrate. If closely pressed he said that they were self-existent from all eternity, or that they had been individually created just as we^ now find them at the present day. Or he might argue that the origin of the elements did not in the lea'st concern us, and was, indeed, a question lying outside the boundaries of science. But in these our times of restless inquiry we cannot help asking what are these elements, whence do they come, what is their signifi- cation ? We cannot but feel that unless some approach to an answer to these questions can be found, our chemistry, after all. is something profoundly unsatisfactory. These elements perplex us in our researches, baffle us in our speculations, and haunt us in our very dreams. They stretch like an unknown sea before us — -mocking, mystifying, and murmuring strange revelations and possibilities. If I venture to say that our commonly received elements are not simple and primordial, that they have not arisen by chance or have not been created in a desultory and mechanical manner but have been evolved from simpler matters— or perhaps indeed from one sole kind of matter— I do but give formal utterance to an idea which has been, so to speak, for some time "in the air " of science. Chemists, physicists, philosophers of the highest merit declare explicitly their belief that the seventy (or thereabouts) elements of our text-books are not the pillars of Hercules which we must never hope to pass. Did time allow I might quote utterances of Dalton, of Professor Faraday, of Dr. Gladstone, of the late Sir Benjamin Brodie, of Professor Graham, of Dr. Mills, of Professor Stokes, of Mr. Norman Lockyer, all pointing in the same direction and all showing that in the course of their researches these servants of Science have been led to think that these same elements are not the final outcome— the be- all and the end-all of chemistry. 38 Mr, William Croohes [Feb. 18, The law of Prout, and still more the better established and far- reaching periodic law of Newlands (since developed by Professors Mendeleeff, Meyer, and Carnelley), seem to presuppose the existence of a genetic relation among the elements. Philosophers in the present as in the past, — men who certainly have not worked in the laboratory, — have reached the same view from another side. Thus Mr. Herbert Spencer records his conviction that *' the chemical atoms are produced from the true or physical atoms by processes of evolution under conditions which chemistry has not yet been able to produce." And the poet has forestalled the philosopher. Milton (' Paradise Lost,' Book V.) makes his Archangel Eaphael say to Adam, instinct with the evolutionary idea, that the Almighty had created ♦' one first matter all. Indued with various forms, various degrees Of substance." If we can show how the so-called chemical elements might have been generated we shall be able to fill up a formidable gap in our knowledge of the universe. We have a preponderance of cumulative evidence to prove that both heavenly bodies and living organisms have been formed by evolution. We are seeking now to extend this law to the so-called elements, to the first principles of which stars and organisms alike consist. If we survey the distribution of the chemical elements we find two very distinct cases. On the one hand we see bodies grouped in definite proportions with other bodies from which they differ exceedingly and to which they are held by affinity, more or less strong. To obtain either of two such bodies in a separate state, that affinity, as every student of chemistry knows, must be overcome. Instances of such association are too common and abundant to need mention. In such cases each of the bodies grouped together has fairly marked properties. One of them, moreover, for the most part has an atomic weight very different from that of the other. In the second case we find bodies associated with other bodies more or less closely allied to themselves. They are not held together by any decided affinity; they are not combined in definite propor- tions, and their atomic weights are often almost identical. If we wish to obtain one or more of these bodies in a separate state, the difficulty encountered lies not in the strength of the affinities to be overcome but in the circumstance that whatever reagent we emjiloy acts upon one of the substances in nearly the same manner as it does upon the other. Hence, to obtain one body of this kind- entirely separate is an exceedingly tedious and difficult task. Nay, we are sometimes at a loss to decide whether we have before us a really simple body or a mixture of bodies whose properties are almost identical. The most striking instance of such association is found in the 1887.] on Genesis of the Elements. 39 metals of the so-called rare earths. These bodies form but a very trifling portion of the earth's crust. They are chiefly met grouped together in a few minerals, such as samarskite and gadolinite, which, so far, have been found in but few localities, and even in those are far from common. These earths form a group to themselves ; chemically, they are so much alike that it taxes the utmost skill of the chemist to efiect even a partial separation, and their history is so obscure that we do not yet know the number of them. It will not be necessary here to explain in detail the process of chemical fractionation adopted for the separation of the rarer earths, since it could interest only the chemical specialist ; moreover, it has been fully described in a paper I read before the British Association at Birmingham. Stated in the briefest way the operation consists in fixing upon some chemical reaction in which there is the most likelihood of a difference in the behaviour of the elements under treatment, even though the difierence be slight, and effecting such treatment incom- pletely, so that only a certain fraction of the total bases present is separated : the object being to get part of the material in an insoluble and the remainder in a soluble state. Let us suppose that we have in solution two earths almost, identical in their properties, but differing slightly, almost imper- ceptibly, in basicity. We add to the solution of the earths, which must be very dilute, weak ammonia to such an amount only that it precipitates one-half of the bases present. The dilution must be so great that a considerable time must elapse before the liquid shows a turbidity, and several hours will have to pass over before the action of the ammonia is complete. The liquid is then filtered, by which process we have the earths divided into two parts, no longer identical in their composition. We can easily see that there is now a slic^ht difference in the basic value of the two portions of earths ; the portion in solution being, though by a scarcely perceptible amount, more basic than that which the ammonia has precipitated. This minute difference is made to accumulate systematically until it becomes perceptible either by chemical or physical tests. The accompanying diagram (Fig. 1), illustrates the scheme of fractionation. Starting from zero at the apex the precipitates all pass to the left and the filtrates to the right. Each circle represents a flask containing the solution under treatment, and the two arrows from each circle show the path pursued respectively by the precipitate and filtrate. Such is the general outline of the process. But, as has been already intimated, the methods of separation suitable for different groups of earths vary. Where the constituents of yttrium and samarium are concerned, nothing seems available but straightforward fractionation continued month after month and year after year. The further question whether an earth we have separated is really simjile or is still a mixture has again to be decided by yet another 40 Mr. William Croohes [Feb. 18, process, to be effected only in a very high vacunm. To understand this process it is necessary to make an apparent total digression. It seems, perhaps, strange to speak of exhausting the air in hollow bnlbs and tubes until there is left in them only the one-millionth Fig. 1. FRACTIONATION OF YTTBIA. J) ca) (2) « e.. @ @ @ @ ® ® @ @ @ 0 0 ^®x®x®x®x®x®x®x®x®x®x®x®x^x-x-x ^ ®@® 00 @®® 0 00 0 01 00-0 ^^©^@V®V@^@^®V-0V®^5VVV@ II illil II IMI! !I Hill II SMII 1 SPECTRA OF FIVE COMPONENTS OF YTTRIA part of an atmosphere. It is only in modern times that atmospheric air has come to be regarded as matter. To this day a bottle or a jar is said to be " empty " if it contains no liquid or solid body, the air with which it is filled being completely ignored. According to the same common idea, how empty then must a vessel be when the air it contains is reduced to the one-millionth part of its original quantity ! That something still remains is, however, proved by the fact that I have succeeded in reducing the pressure down to one fifty-millionth of an atmosphere. What this number represents will be better under- stood if I say that, given a barometric column one hundred miles in height, the remaining pressure would be equal only to about the tenth of an inch. Even this high degree of exhaustion by no means represents an absolute vacuum. I have in this glass tube perhaps the nearest approach to perfect emptiness yet artificially obtained. Its internal capacity is 5 cubic centimetres, and it is exhausted to the one fifty-millionth part of an atmosj)here. It still contains 100,000000,000000 molecules. The internal space, therefore, is far, very far, from being absolutely void of matter. 1887. on Genesis of the Elements. 41 The vacuum most suitable for experiments on tliese earths is one of about the millionth of an atmosj^here. In a vacuum of this degree we find under the action of the induction-spark certain substances phosphorescing or behaving very differently from what they would if similarly treated at a lower vacuum or at the ordinary pressure of the atmosphere. When thus treated, the examination of the spectra of the phosphorescing earths furnishes what I have ventured to call the radiant matter test. After a time, on examining the series of yttrium earths in the lowest line of flasks, their phosphorescent spectra are found to have become modified in the relative intensities of some of their lines. Ultimately different portions of the fractionated yttria give the five- spectra approximately shown at the foot of the diagram ; whilst Samaria also appears capable of being split up into two or perhaps three constituents. These bodies, it must be clearly understood, are not impurities which may be removed, yttrium or samarium remaining in a pure state after their elimination. On the contrary, the molecule we formerly knew as yttrium has undergone a veritable splitting up into its constituents. These constituents I have not as yet formally baptised. For more convenient reference and "discussion I have provisionally ticketed them, as shown in the following Table. Table I. IVfean Position of Lines Scale of Wave- 1 Provisional Name. in the Sppctro- lenRth of X"^ Probabilily. Sped nun. scope. Line or Band. Briglit lines in — Violet 8-515 456 4809 S7 New, or ytterbium. Deep bhie 8-931 482 4304 Ga New. Greenish blue ^meanj of a close pair) . . / 9 650 545 3367 G)8 { New, or the Z/3 of M. de Boisbaudran. Green 9-812 564 3144 G7 G5 { New. New, or the Za of M. Citron 9-890 574 3035 de Boisbaudrau. Yellow 10-050 597 2806 Ge New. Orange 10-129 609 2693 S5 New. Red 10-185 619 2611 GC New. Deep red 10-338 647 2389 Gr, New. I will rapidly sketch the most salient features of the rare earths when submitted to the radiant matter test. Some remain unaffected and thus are referred at once to a distinct group. Others have the curious property of preventing the induction-spark passing, and so simulating a non-coi]ducting vacuum, when there is really plenty of residual gas present. The rare earth thoria possesses in the highest 42 Mr. William Crookes [Feb 18, degree this obstructive property. Before me I have an exhausted tube having two sets of poles sealed in it, one set at each end. The size and distance apart of these poles are exactly the same in each case. At one end of the tube I have put some thorium sulphate, at the other end I have put yttrium sulphate. The exhaustion is now proceeding by aid of the Sprengel pump. I attach the wires of the induction coil to the poles at the thorium end, and, as you see, no current will pass ; rather than pass through the tube, the spark prefers to strike across the spark-gauge in air — a striking distance of 37 millimetres, — showing an electromotive force of 34,040 volts. Now, without doing anything to affect the degree of exhaustion, I transfer the wires of the induction coil from the thorium to the yttrium end, and the spark passes at once. To balance the spark in air I must push the wires of the gauge together, till they are only 7 millimetres apart, equivalent to an electromotive force of 6440 volts : the fact of whether thoria or yttria is under the poles making a difference of 27,600 volts in the conductivity of the tube. The explanation of this eccentric action of thoria is not yet quite clear. From the great difference in the phosphorescence of the two earths, it is evident that the passage of electricity through these tubes is not so much dependent on the degree of exhaustion as upon the phosphorogenic property of the body opposite the poles. Other earths become very phosphorescent, and their power of retaining residual phosphorescence differs greatly among themselves. This property we shall presently see is one of some importance. To examine this persistence of luminosity I have devised an instrument similar to Becquerel's phosjphoroscope, but acting electrically instead of by means of direct light. It consists of an oj^aque disc, 30 inches in diameter, pierced with six openings near the edge. By means of a multiplying wheel and pulley the disc can be set in rapid rotation. At each revolution a stationary object behind one of the apertures is alternately exposed and hidden six times. A commutator forms part of the axis of the disc, and by connecting it with the wires from a battery, rotation of the disc produces alternate makes and breaks in the current. This primary current is then connected with the induc- tion coil, from which the secondary current passes through the vacuum tube containing the earth under examination. When a phosphorescent body such as yttria is examined, if the wheel is turned slowly no light is seen when looked at from the front, as the current does not begin till the obscuration of the tube by an intercepting segment, and ends before the earth comes into view. "When, however, the wheel is quickly turned, the residual phos- phorescence lasts long enough to bridge over the brief interval between the cessation of the spark and the entry of the phosphor- escent body into the field of view, and it is seen to glov/ with a faint light which becomes brighter as the s])eed of the wheel increases. I will first put the phosphorescent earth glucina in the phos- phoroscope. This phosphoresces of a bright blue colour, but the 1887.] on Genesis of the Elements. 43 residual glow is so short that, with the highest speed of which the instrument is capable, you see no light whatever. In contrast I now put in a compound of the earth strontia. This also glows with a rich blue colour, showing in the spectroscope a continuous spectrum with a great concentration of light in the blue and violet. In the phos- phoroscope the colour of the glow is bright green, showing in the spectroscope a continuous spectrum, with the red and blue ends cut off. Alumina in the radiant matter tube glows with a rich crimson light. I will put some rubies — a crystalline form of alumina — in the phosphoroscope. Here the persistence of luminosity is so great that the red light is visible with the slowest speed, and with a high velocity the residual glow is nearly as strong as when the rubies are out of the instrument. Shakespeare, who is supposed to have mastered all knowledge, had he seen these rubies could hardly have described them more precisely than in the lines from ' Julius Caesar ' : — "... with unnumbered sparks They are all fire, and every one doth shine." Another distinctive phenomenon is that the earths of one group, yttrium and samarium, when submitted to the induction discharge in vacuo, yield discontinuous spectra. These spectra are extremely complicated and change in their details in a puzzling manner. For many years I have persistently groped on in almost hopeless endeavour to get a clue to the meaning which I felt convinced was locked up in these systems of bands and lines. It was impossible to divest myself of the conviction that I was ].ooking at a series of autograph inscriptions from the molecular world, evidently of intense interest, but written in a strange and baffling tongue. For a long time all attempts to decipher these mysterious signs were fruitless. The meaning of the strongly-marked symbolic lines had first to be ascertained. After continued efforts I had to be content with roughly translating one group of coloured symbols as " yttrium " and another group as " samarium," disregarding the fainter lines, shadows, and wings frequently common to both. Constant practice in the decipherment has now given me fuller insight into what I may call the grammar of these hieroglyphic inscriptions. Every line and shadow of a line, each faint wing attached to a strong band, and every variation in intensity of the shadows and wings among themselves, has now a definite meaning which can be translated into the common symbolism of chemistry. This leads us to what I may call the history of yttrium. Twelve months ago the name yttrium conveyed to all chemists a perfectly definite meaning. It was supposed to be an elementary or simple body, having a fixed atomic weight, 88 • 9, and its principal properties had been duly determined. Its phosphorescent spectrum gave a definite system of coloured bands, such as you see in the drawing 44 3Ir, William Croohes [Feb. 18, before you (Fig. 2). Broadly speaking, there is a deep red band, a very luminous citron-coloured band, a pair of greenish-blue bands, and a blue band. These bands, it is true, varied slightly in relative intensities and in sharpness with almost every sample of yttria 10 1 50 1 :>o mill £ h 1 II . Fi:^.Z. Yttrca J^y J. 1^ (Gaddiniaj Fzq. 4. YUriaej 'Sfamaria 59. I examined ; yet the general character of the spectrum remained unchanged, and I habitually looked upon this spectrum as charac- teristic of yttrium ; all the bands being visible when the earth was present in quantity, whilst only the strongest of all — the citron band — was visible when traces, such as millionths, were present. But that the whole system of bands spelled yttrium, and nothing but yttrium, I was firmly convinced. The differences in the spectra of yttrium prepared from different sources are most distinctly seen on comparing the spectrum of yttrium from samarskite with that from gadolinite, hielmite, monazite, xenotime, fluocerite, euxenite, cerite, arrhenite, &c. Still, in spite of these slight differences, the several yttriums are practically all the same thing, and, as I have said, every living chemist a year ago would have regarded them as identical. Eut they have since yielded to persistent chemical fractionation, and I now call them old yttrium. One property, above all others, is relied on by chemists as an indisputable proof of the identity of any particular chemical element. 1887.] on Genesis of the Elements. 45 When the vapour of an element is rendered incandescent by the electric spark, the characteristic system of lines in its sj^ectrum is regarded as unalterable, and is looked upon as a certain proof tliat this special element is under examination. However much chemical or other tests fail to show the presence of a given element, the indications of its lines in the spectroscope are regarded as infallible. Spectrum analysis is the court of final apj)eal, whose decision no chemist has yet had the hardihood to dispute. By way of illustration I will project on the screen the very characteristic system of lines given by yttrium when ignited by the electric spark, — a system, be it remembered, having no connection "whatever with the peculiar phosphorescent spectrum yielded by yttrium. The coloured diagram gives as accurate a representation of the spark spectrum of yttrium as can be drawn by hand. Omitting minor lines you will notice two very strong groups of lines in the red and orange. These lines have been always regarded as the charac- teristic test for yttrium ; the presence of these groups proves the presence of yttrium, and tlieir absence proves its absence. I now project the electric spark spectrum of GS as pure as I have been able to prepare it. GS is one of the bodies which by long and tedious fractionation I have separated from yttrium ; it occurs at one extreme end of the fractioning, and dififers not only from the parent yttrium in its phosphorescent spectrum, but by virtue of the process adopted for its isolation, it must likewise diifer in chemical properties. But what tale does the spectrum tell ? It tells us there is absolutely no difference between this spectrum and that given by old yttrium. I now pass to the other end of the fractionation of yttrium, v^here a body, Grj, concentrates giving a totally different phosjDhorescent spectrum to that given by G8. And it also differs chemically from old yttrium, and in a more marked manner from its brother, GS, at the other extremity of the fractionation. Look at its spark spectrum ! It is perfectly identical both with old yttrium and with G8, and when I examine these three spectra in my laboratory with all the appliances for exact measurement, the whole system of lines is still identical. What inference can be drawn from these results ? Is discredit to be thrown on spectrum analysis ? Is the superstructure which has been so laboriously raised upon its indications to fall to the ground ? By no means. Spectrum analysis and its grand generalisations are on as firm a foundation as ever. I see two possible explanations of the facts I have brought before you. According to one hypothesis research has somewhat enlarged the field lying between the indications given by ordinary coarse chemistry and the searching scrutiny of the prism. Our notions of a chemical element have expanded. Hitherto the molecule has been regarded as an aggregate of two or more atoms, and no account has been taken of the architectural design on which these atoms have been joined. We may consider that the structure of a chemical clement is more complicated than has hitherto been 46 Mr. William Croolces [Feb. 18, supposed. Between tlie molecules we are accustomed to deal with in chemical reactions and ultimate atoms as first created, come smaller molecules or aggregates of physical atoms ; these sub-molecules difier one from the other, according to the position tbey occupied in the yttrium edifice. Perhaps this hypothesis can be simplified if we imagine yttrium to be represented by a five-shilling piece. By chemical fractionation I have divided it into five separate shillings, and find that these shillings are not counterparts, but like the carbon atoms in the benzol ring, have the impress of their position, 1, 2, 3, 4, 5, stamped on them. These are the analogues of my Ga, G/3, &c. If I now bring in a much more powerful and searching agent — if I throw my shillings into the melting-pot or dissolve them chemically — the mint stamp disappears and they all turn out to be silver. I submit my yttrium, or my Ga, G(3, &c., to the intense heat of the electric spark, the little differences of molecular arrangement vanish, and the atoms of which the molecules of yttrium, Ga and G(3, are alike composed, reveal their presence in identical sj^ectra. An alternative theory commends itself to chemists, to the effect that the nine bodies shown in the above table (Table I.), are new chemical elements differing from yttrium and samarium in basic powers and several other chemical and physical properties, but not sufficiently to enable us to effect any but a slight separation. One of these bodies, G8, gives the phosphorescent citron line, and also the brilliant electric spectrum I have just exhibited. The other eight do not give electric spectra which can be recognised in the presence of a small quantity of G8, whilst the electric spectrum of G8 is so sensi- tive that it shines out in undiminished brilliancy even when the quantity present is extremely minute. In the process of fractionation, Ga, G/3, GB, &c., are spread out and more or less separated from one another, yet the separation is imperfect at the best, and at any part there is enough G8 to reveal its presence by the sensitive electric spark test. The arguments in favour of each theory are strong and pretty evenly balanced. The compound molecule explanation is a good working hypothesis, which I think may account for the facts, while it does not j^ostulate the rather heroic alternative of calling into existence eight or nine new elements to explain the phenomena. However, I submit it only as an hypothesis. If further research shows the new element theory is more reasonable, I shall be the first person to accept it.* * Neither of these theories agrees with that of my distinguished friend M. Lecocq de Boisbaudran, who also has worked on Ihese earths for some time. He considers that what I have called old yttrium is a true element, characterised by the spark spectrum already exhibited, but not giving a phosphorescent spectrum in vacuo. The bodies giving the phosphorescent spectra he considers to be impurities in yttrium. These he says are two in number, and he has pro- visionally named them Za and Z/3. By a method of his own, differing from mine, M. de Boisbaudran obtains fluorescent spectra of these bodies; but their 1887.] on Genesis of the Elements. 47 I now will introduce to yon a substance which has been to me what the celebrated Rosetta stone was to the interpreters of Egyptian inscriptions. I received it from M. de Marignac, and it was nothing more than a small specimen of a new earth which he had obtained and had named provisionally Ya. In the radiant-matter tube this earth gives a bright spectrum as in the diagram before you (Fig. 3). If we compare this spectrum with that ascribed to " old yttrium " (Fig. 2) we see that, omitting minor details, Ya is yttrium with the characteristic citron band left out and the green and orange bands of samarium added. Now look at the following diagram (Fig. 4), which represents the spectrum of a mixture of 61 parts of yttrium and 39 parts of samarium. It is almost to its minutest details identical with the spectrum of Ya, but the citron band is as prominent as any other band. Hence Ya is shown to consist of samarium, with the greenish blue of yttrium and some of the other yttrium bands added to it. It proves, further, that the citron band which I had hitherto regarded as one of the essential bands of the yttrium spectrum can be entirely removed, whilst another characteristic yttrium group, the double green band, can remain with heightened brilliancy. If now it were possible to remove the citron band-forming body from this mixture, I should leave Ya behind ; I should, in fact, have recomposed Ya from its elements. "I have no doubt whatever that this will ultimately be accomplished, but the preliminary work of fractionation is tedious to the last degree, and for its completion would occupy a space of time in comi^arison with which the life of man is all too brief. Whilst I have not yet chemically removed the citron -forming con- stituent, I can physically suppress the citron band and show an artificial spectrum, imitating in the closest degree the natural si)ectrum of Ya. By means of the electrical phosphoroscope I am enabled to catch the spectrum of an earth immediately after it has suffered molecular bombardment in the vacuum. In this way I get the spectrum of the residual phosphorescence, and I have found that not all the con- stituents of these earths emit residual phosphorescence for the same duration of time. When a little strontium is added to the yttrium-samarium mixture, the effect in the phosphoroscope is to suppress the residual phosj^hor- fluorescent bands are extremely hazy and faint, rendering identification difficult. Some of tliem fall near lines in the spectra of my G)8 and G5. At first sight it miglit appear that his and my spectra were due to the same bodies, but, according to M. de Boisbaudran, the chemical properties of the earths producing them are widely distinct. Those giving phosphorescent lines by my metliod occur at tlie yttrium extremity of the fractionation, where his fluorescent bands are scarcely shown at all ; whilst his fluorescent phenomena are at their maximum quite at the terbium end of the fractionation, where no yttrium can he detected even by the direct spark, and where my phosphorescent lines are almost absent. 48 Mr. William CrooJces [Feb. 18, escence of GS — the citron band— and to enhance the iDhosphoreccence of G^, the double green band, and the imitation of the Ya spectrum is complete. I must here call attention to the experiments of Prof. A. E. Nordenskiold, in the Comptes Rendus of the French Academy of Sciences for November 2nd, 1886. This eminent savant is working in the same direction as myself, with results which decidedly corroborate my experiments. He has taken the crude mixture of yttria, erbia, ytterbia, &c., just as it is precipitated from the minerals containing these rare earths. This mixture, for brevity's sake, he calls gado- linia, and he finds that this gadolinia, though palpably a compound body, has always a constant atomic weight, whatever the mineral from which it has been extracted. Or, to use Prof. Nordenskiold's own words, " Oxide of gadolinium, thoiigli it is not the oxide of a simple body, hut a mixture of three isomorphous oxides (even when it is derived from totally different minerals found in localities far apart from each other) possesses a constant atomic weight." Therefore, as he signi- ficantly observes, " We are in presence of a fact altogether neiv in chemistry. For the first time we are conf routed with the fact that three isomorphous substances, of a kind that chemists are still com- pelled to regard as elements, occur in nature not only always together, but in the same proportions. It seems that chemists here find them- selves face to face with a problem analogous to that presented to astronomers in the origin of the minor planets." These facts throw a new light upon certain important chemical questions. For the old yttrium passed muster as an element. It had a definite atomic weight, it entered into combination with other elements, and could be again separated from them as a whole. But now we find that excessive and systematic fractionation has acted the part of a chemical " sorting Demon," distributing the atoms of yttrium into groups, with certainly different phosphorescent spectra, and presumably different atomic weights, though, from the usual chemical point of view, all these groups behave alike. Here, then, is a so-called element whose spectrum does not emanate equally from all its atoms ; but some atoms furnish some, other atoms others, of the lines and bands of the compound spectrum of the element. Hence the atoms of this element differ probably in weight, and certainly in the internal motions they undergo. This is unlikely to be an isolated case. We may assume that the principle is of general application to all the elements. In some, possibly in all elements, the whole spectrum does not emanate from all their atoms, but different spectral rays may come from different atoms, and in the spectrum as we see it all these partial spectra are present together. This may be interpreted to mean that there are definite differences in the internal motions of the several groups of which the atoms of a chemical element consist. For example, we must now be prepared for some such events as that the seven series of bands in the absorption-spcctruui of iodine may prove not all to 1887.] on Genesis of the Elements. 49 emanate from every molecule, but that some of these molecules emit some of these series, others others, and in the jumble of all these molecules, to which is given the name " iodine vapour," the whole seven series are contributors. Another important inference to be drawn from the facts is that yttrium atoms, though differing, do not differ continuously, but per saltiim. We have evidence of this in the fact that the spectroscopic bands characteristic of each group are distinct from those of other groups, and do not pass gradually into them. We must accordingly expect, in the present state of science, that this is probably the case with the other elements. And the atoms of a chemical element being known to differ in one respect may differ in other respects, and presumably do somewhat differ in mass. Eeturning, after this digression, to the idea of heavy and light atoms, we see how well this hypothesis accords with the new facts here brought to light. From every chemical j^oint of view the stable molecular group, yttrium, behaves as an element. To split up yttrium requires not only enormous time and material, but the existence of a test by means of which the constituents of yttrium are capable of recognition. Had we tests as delicate for the constituent molecular groups of calcium, this element also might be resolved into simpler groupings. It is one thing, however^ to find out means of separating bodies which we know to be distinct and to have colour or spectrum reactions to guide us at every step ; it is quite another thing to separate colourless bodies which are almost identical both in chemical reaction and atomic weight, especially if we have no suspicion that the body we examine is a mixture. Again, it seems as if bodies we have been accustomed to regard as absolutely simple and elementary may be split up in different directions according to the means we bring to bear upon them. Until very lately our text-books made mention of an element under the name of didymium. With some trouble it had been separated from its accomjDanying bodies lanthanum and cerium. Its properties had been examined, and no one doubted its distinct and elementary character. It was viewed according to one of the common definitions of an element, as " a something to which we can add, but from which we can take nothing." When, behold! Dr. Auer von Welsbach, examining this supposed simple body in a novel manner, succeeded in decomposing it into two simpler bodies, which he called neodymium and praseodymium ; and later researches, in which I have had a share, show that even neodymium and praseodymium are not the simplest bodies into which didymium can be dissected. But it may be asked. What is the bearing of all this upon the great question of the genesis of the elements '? Have we chemists merely discovered some new '• elements," or found out that a body hitherto held to be simple is in reality complex ? We liave, I submit, done something decidedly different. If a metal which is found to have a fixed atomic weight is discovered to be a compound or a Vol. XIL (Xo. 81.) e 50 Mr. William Crookes [Feb, 18, mixture, our best test for recognising an element, so-called, bas melted away ! Hitberto it bas been considered tbat if tbe atomic weigbt of a metal, determined by different observers, setting out from different compounds, was always found to be constant (witbin, of course, tbe limits of experimental error), then sucb metal must rightly take rank among tbe simple or elementary bodies. We learn from Nordenskiold's gadolinium tbat this is no longer tbe case. Again, we have here wheels witbin wheels. Gadolinium is not an element, but a compound, or rather, perhaps, a mixture of yttrium, erbium, and ytterbium. We have shown tbat yttrium is a complex of five or more new constituents. And who shall venture to gainsay that each of these constituents, if attacked in some different manner, and if tbe results were submitted to a test more delicate and searching than tbe radiant-matter test, might not be still further divisible? Where, then, is tbe actual ultimate element ? As we advance it recedes like the tantalising mirage lakes and groves seen by tbe tired and thirsty traveller in tbe desert. Are we in our quest for truth to be thus deluded and baulked ? The very idea of an element, as something absolutely primary and ultimate, seems to be growing less and less distinct. But we have by no means done with the rare earths and their lessons. How is it tbat these bodies are found, as w^e actually find them, associated in certain rare minerals sucb as samarskite and gadolinite, but occurring only in a few localities ? This fact is bard to account for on tbe ordinary theories of the origination of the elements. I venture provisionally to conclude that our so-called elements or simple bodies are, in reality, compound molecules. To form a conception of their genesis I must beg you to carry your thoughts back to the time when the visible universe was " without form and void," and to watch the development of matter in tbe states known to us from an antecedent something. What existed anterior to our elements, before matter as we now have it, I propose to name protyle* * We require a word, analogous to protoplasm, to express the idea of tbe original primal matter existing before the evolution of the chemical elements. The word I have ventured to use for this purpose is compounded of -n-pS (earlier than) and uA-tj (the stuff of which things are made). The word is scarcely a new coinage, for in the ' Wisdom of Solomon ' (xi., v. 17) we read : — " Thy almighty liaud, that created the world — e| aii6p(pov uX-qs — out of formless stuff," the word here rendered "stuff" being in the original uAtjs, from which I have ventured to coin the word " protyle." Six hundred years ago Roger Bacon wrote in his De Arte ChymicE, " The elements are made out of vXy], and every element is con- verted into the nature of another element." Professor Huxley reminds me that vXt], in the general sense of material substance, was first used by Aristotle, in whose works it is of very frequent occurrence. In fact the fundamental distinc- tion in his Physical Philosophy is between uAtj, or rndter, and (l^os, or form., which last pretty nearly answers to what we should call the sum total of the qualities, powers, and tendencies of a thing — or of forces as the cause of these. In the metaphysics and elsewhere Aristotle distinguishes (1) UpcoTTj v\7], "Materia 1887.] on Genesis of the Elements. 51 But how can we suppose tbe protyle, or fire-mist, converted into the atomic condition ? In amorphous matter we recognise a tendency to aggregation not to be identified with gravitation, since it is mani- fested among finely-divided matter, whether suspended in a medium of a si^ecific gravity superior, equal, or inferior to its own. This agglutinative action is familiar to observers of natural phenomena. Clouds contracting to that appearance known as a mackerel sky ; particles of carbon floating in the air, collecting, and ultimately falling as " blacks " ; chemical precipitates, at first finely amorphous, but gradually becoming flocky, granular, and crystalline ; vortex rings, suddenly quickening out of amorphous smoke;— all these, and many more, exemplify that universal formative principle in nature which I suggest first made itself manifest in the condensation of protyle into atomic matter. A few weeks ago, in this theatre, Sir William Thomson asked you to travel back with him an imaginary excursion of about twenty million years. He pictured to you the moment immediately before the birth of our sun, when the Lucretian atoms rushed from all parts of space with velocities due to mutual gravitation, and, clashing together, formed in a few hours an incandescent fluid mass, the nucleus of a solar system with thirty million years of life in it. I will ask you to accompany me to a period even more remote, — to the very beginnings of time, before even the chemical atoms had con- solidated from the original protijU. Let us imagine that at this primal stage all was in an ultra-gaseous state — a state difi'ering from anything we can now conceive in the visible universe. Now unless the expression " fire-mist " and the supj)Osition that pristine matter was once in an intensely heated condition * are quite misleading and baseless, we have to deal with a process analogous to cooling. This operation, probably internal, reduces the temperature of the cosmic protyle to a point at which the first step in granulation takes place ; matter as we know it comes into existence, and atoms are formed. As soon as an atom is formed out of protyle it is a store of energy, kinetic (from its internal motions), and potential (from its tendency to coalesce with other atoms by gravitation or chemically). To obtain this energy the neighbouring protyle must be laid under contribution, i, e. must be refrigerated by it, thereby accelerating the subsequent formation of other atoms. With the birth of gravitating Prima," or matter undifferentiated into elements, without form, in fact, and consequently ayvoiaros, unknown and unknowable, and (2) ia-xarr] v\t]. secondary or formed matter, such as earth, or metal, or water, or any other raw material with which we are familiar. * I am constrained to use words expressive of high temperature; but I confess I am unable clearly to associate with protyle the idea of hot or cold. Temjyerature, radiation, and free cooling seem to require the periodic motions that take place in the chemical atoms; and the introduction of centres of periodic motion into protyle would involve its being so far changed into chemical atoms. Probably the first operation was more analogous to the formation of vortex rings than to a reduction of temperature. E 2 52 3Ir. William CrooJces [Feb. 18, matter, rushing suddenly together from every point of space, we thus get Sir William Thomson's incandescent mass which is presently to cool down into a solar system. We cannot tell if electricity existed prior to the origin of the atomic condition of matter, but with the formation of atomic matter the other forms of energy which require matter in order to manifest themselves, begin to act, amongst others that form of energy which has for one of its factors that which we now speak of as atomic weight. We have now to seek how protyle was converted not into one only kind of matter but into many. If we recognise that it contained within itself the potentiality of all atomic weights, how did these potentialities become actual ? We may here call to mind the sug- gestion of Dr. E. J. Mills, that our elements are the result of suc- cessive polymerisations during the cooling process. We shall also derive much assistance from a method of illustrating the periodic law proposed by my friend Professor Emerson Keynolds, of the University of Dublin. I must call your attention to a diagram (Fig. 5) in which I have slightly modified the original design of Professor Reynolds. I have represented the pendulum swing as gradually declining in amplitude according to a mathematical law. I have further interposed between cerium and lead another half-swing of the pendulum. This renders the oscillations more symmetrical and brings gold, mercury, thallium, lead, and bismuth to the side where they are fully in harmony with members of previous groups. The chemical elements are arranged in order, according to their atomic weights, on the centre vertical line which is divided into equal parts. Following the curve from hydrogen downwards, we see that the elements forming the eighth group of Mendeleeff's arrangement are situate near three of the ten nodal points. This eighth group is divided into the three triplets — iron, nickel, and cobalt ; rhodium, ruthenium, and palladium ; iridium, osmium, and platinum. These bodies are interperiodic because their atomic weights exclude them from the small periods into which the other elements fall, and because their chemical relations with some members of the neighbouring groups show that they are probably interperiodic in the sense of being in transition stages. Notice how accurately the series of like bodies fits into this scheme. Beginning at the top, run the eye down analogous positions in each oscillation, taking either the electro-positive or electro-negative swings. (See Table, p. 51.) Notice, also, how orderly the metals discovered by spectrum analysis fit in their places — gallium, indium, and thallium ; rubidium and caesium. The symmetry of nearly all this series proclaims at once that we are working in the right direction. Much also may be learned from the anomalies here visible. A few bodies, such as didymium, erbium, 1887.- on Genesis of the Elements. Fig. 5. 53 54 Mr. William Croohes [Feb. 18, thulium, and ytterbium, are out of place, and require to have their atomic weights redetermined. Table II. T \ VERTICAL Series OF THE Elements. Even. Odd. iv. iii. iii. V. ii. ii. vi. i. i. vii. i. vii. i. ii. ii. vi. iii. V. iii. iv. C B N Be 0 Li F CI Na S Mg P Al iSi Ti Sc V Ca Cr K Mn Br Cu Se Zu As Ga Ge Zr Yt Nb Sr Mo Kb — I Ag Te Cd Sb In Sn Ce La — Ba Sm Cs — — — — — — — — — — — — — — — All — Hg Bi Tl Pb The more I ponder over the arrangement of this zigzag curve, the more I become convinced that he who fully grasps its meaning holds the key to unlock some of the deepest mysteries of creation. As Mr. Browning puts it in his ' Parleyings ' — " 'Tis Man's to explore Up and down, inch by inch, with the taper his reason." Let us batter at the door of the Unknown and do our utmost to get a glimpse of some few of the secrets so darkly hidden. Let us return in imagination to pre-geological ages, before the sun himself had been aggregated from the original protyle. We require two very reasonable postulates ; let there be granted an antecedent form of energy having jDcriodic cycles of ebb and swell, rest and activity. Let there also be granted an internal action akin to cooling operating slow^ly in the protyle. The first-born element would, in its simplicity, be most nearly allied to protyle. This is hydrogen, of all known bodies the simplest in structure and of the lowest atomic w^eight. For some time hydrogen would be the only existing form of matter (in our sense of the term). Between hydrogen and the next formed element there would be a gap in time, and in the interval the element standing next in order of simplicity would gradually be approaching its birth-point. In this interval we may sujipose that the evolutionary process soon to deter- mine the birth of a new element would fix likewise its atomic weight, its affinities, and its chemical position. In this genesis of the elements the longer the time taken up in the cooling-down process, during which the hardening of protyle into atoms takes place, the more sharj)ly defined would be the resulting elements ; whilst the more raj^id and the more irregular the cooling, the more closely the resulting bodies w^ould fade into each other by almost imperceptible degrees. Thus we may conceive that the succession of events which gave rise to such groups as platinum, osmium, and iridium, — palladium, ruthenium, and rhodium, — iron, nickel, and cobalt, — might have produced only one element in each of these three groups if the process had been greatly prolonged. And conversely, had the rate of cooling been much more rapid, elements might have originated still more nearly identical than are 1887.] on Genesis of the Elements. 55 nickel and cobalt. Thus may have arisen the closely allied elements of the cerium, yttrium, and similar groups. In fact, we may regard the collocation of the minerals of the class of samarskite and gadolinite as a kind of cosmical lumber-room where elements in a state of arrested development — the unconnected missing links of inorganic Darwinism — are gathered together. Any well-defined element may be likened to a jilatform of stability, connected by ladders of unstable bodies. In the first coalescence of the primitive stuif there w^ould be formed the smallest atoms ; these woukl then unite, forming larger groups ; the gaps between the several stages would gradually be bridged over and the stable element appropriate to that stage would absorb, so to speak, tho unstable rungs of the ladder which led up to it. It may be ques- tioned whether there is an absolute uniformity in the mass of every ultimate atom even of one and the same chemical element. Pi-obably our atomic weights merely represent a mean value around w^hich the actual atomic weights of the atoms vary within certain narrow limits. When, therefore, we say that, e. g. the atomic weight of calcium is 40, the actual fact may well be, that whilst the majority of the calcium atoms really have the atomic weight of 40, some are repre- sented by 39-9 or 40-1, a smaller number by 89 '8 or 40*2, and so on. The properties which w^e perceive in any element are thus the mean of a number of atoms differing among themselves very slightly, but still not identical.* Is this the true meaning of Newton's " old worn particles ? " That this speculation, hazardous as it may seem, is in some respects supported by the experimental results above described will, I think, be admitted. It seems to me that the hypothesis I have just suggested, if taken in conjunction with the diagram. Fig. 5, enables us to proceed a step or two further along the track of the evolution of the elements. We may trace in the undulating curve the action of two forms of energy, the one acting vertically and the other vibrating to and fro like a pendulum. Let the vertical line represent tem- perature gradually sinking through an unknown number of degrees from the dissociation-point of the first-formed element downwards to the dissociation-jioint of the last member of the scale. But what form of energy is figured by the oscillating line? We see it swinging to and fro to points equidistant from a neutral centre. We see this divergence from neutrality confer atomicity of one, two, three, or four degrees as the distance from the centre increases to one, two, three, or four divisions. We see the approach to or the retrocession from this same neutral line deciding the electro-negative * I venture to suggest that the heavier and lighter atoms formed from the protyle may have been partially sorted out by a process in nature somewhat analogous to the fractionation which has been already described. Such a sorting out would be effected chiefly whilst atomic matter was condensing from the primal state ; but it may also have been carried on during geological ages in the wet way by successive solutions and re-precipitations of the various earths. 56 3Ir. WiUiam Crookes [Feb. 18, or electro-positive character of each element ; those on the retreating half of the swing being positive, and those on the approaching half negative. In short, we are led to suspect that this oscillating power must be closely connected with the imponderable matter, essence, or source of energy we call electricity. Let us now return to the period just preceding the birth of the first element. Before that time matter as it now is manifested did not exist. We can no more conceive of matter without energy than of energy without matter ; indeed from one point of view the two are convertible terms. Let us assume that simultaneously with the creation of atoms all those attributes which enable us to discriminate one form of matter from another, start into being endowed with energy. Our pendulum begins its swing from the electro-positive side ; lithium, next to hydrogen in the simplicity of its atomic weight, is now formed, followed by glucinum. boron, and carbon. Each element, at the moment of birth, takes up definite quantities of electricity, and on these quantities its atomicity depends.* Thus are fixed the types of the monatomic, diatomic, triatomic, and tetratomic elements. It has been pointed out by Dr. Carnelley that " those elements belonging to the even series of the periodic classification are always paramagnetic, whereas the elements belonging to the odd series are always diamagnetic." Now in our curve the even series to the left, so far as has been ascertained, are paramagnetic, whilst, with a few exceptions, all to the right are diamagnetic. The strongly magnetic grouj^, iron, manganese, nickel, and cobalt, lie close together on the projDer side. But the interperiodic groups, of which palladium and platinum are respectively examples, are supposed to be feebly mag- netic. If this can be verified they form exceptions which have yet to be explained. Oxygen, which weight for weight is even more strongly magnetic than iron, lies near the beginning of the curve, whilst at the opposite end come the powerfully diamagnetic metals, bismuth and thallium. We come now to the return or negative part of the swing ; nitrogen api3ears and shows instructively how position governs the mean dominant atomicity. Nitrogen occupies a position immediately ^ * " Nature presents ns with a single definite quantity of electricity. . . . For each chemical bond which is ruptured within an electrolyte a certain quantity of electricity traverses the electrolyte, which is the same in all cases." — G. Johnstone Stoney, " On the Physical Units of Nature." — British Associa- tion Meeting, 1874, Section A. Phil. Mag., May, 1881. " The same definite quantity of either positive or negative electricity moves always with each univalent ion, or with every unit of affinity of a multivalent ion."— Helmholtz, Faraday Lecture, 1881. "Every monad atom lias associated with it a certain definite quantity of electricity ; every dyad has twice this quantity associated with it ; every triad three times as much, and so on." — O. Lodge, "On Electrolysis," British Associa- tion Beport. 18S5. 1887.] on Genesis of the Elements. 57 below boron, a triatomic element, and, therefore, nitrogen is likewise triatomic. But nitrogen also follows upon carbon, a tetratomic body, and occupies the fifth position if we count from the place of origin. Now these seemingly opposing tendencies are beautifully harmonised by the endowment of nitrogen with a double atomicity, its atom being capable of acting either as a tri- or as a pentatomic element. With oxygen (di- and hexatomic) and fluorine (mon- and heptatomic) the same law holds good, and one half-oscillation of the pendulum is completed. Passing the neutral line again, we find successively formed the electro-positive bodies sodium (monatomic), magnesium (diatomic), aluminium (triatomic), and silicon (tetratomic). Here we may notice a curious coincidence ; at the beginning of this part of the curve stands carbon, the most ubiquitous element in the organic world. At the end, in opposition, stands silicon, the most commonly occurring element in the inorganic sphere. Further, as we move towards the median line, carbon is successively followed by nitrogen, oxygen, and fluorine, all entering into organic com- pounds and all gaseous in the free state. If we work back from silicon we find aluminium, magnesium, and sodium, all much less disposed to volatility, and all very prominent members of the mineral kingdom. The first complete swing of the pendulum is accomplished by tho birth of the three electro-negative efements, phosphorus, sulphur, and chlorine ; all three, like the corresponding elements on the opposite homeward swing, having at least a double atomicity, depending on position. Let us pause and examine the results. We have now formed the elements of water, of air, of ammonia, of carbonic acid, of plant and animal life ; we have phosphorus for the brain, salt for the sea, clay and sand for the solid earth ; two alkalies, an alkaline earth, an earth, along with their carbonates, borates, nitrates, fluorides, chlorides, sulphates, phosphates, and silicates, sufficient, it may be said, for animal and vegetable life, and for a world not so very different from that in which we live and move. Again let us follow our pendulum. After the formation of chlorine this pendulum touches the neutral line, and is in the same position as in the beginning. Had everything remained as at first the next element to appear would again have been lithium, and the original cycle would have been eternally reiDcated, producing again and again the same fifteen elements. The conditions, however, are no longer the same : time has elapsed and the form of energy re- presented by the vertical line has declined ; in other words, the temperature has sunk, and the first element to come into existence when the pendulum starts for its second oscillation is not lithium, but the metal next allied to it in the series, i. e. potassium, which may be regarded as the lineal descendant of lithium, with the same hereditary tendencies, but with less molecular mobility and a higher atomic weight. 58 3Ir. William CrooJces [Feb. 18, Pass along the curve and in nearly every case the same law holds good. Thus the last element of the first complete vibration is chlorine. In the corresponding j)lace in the second vibration we have not an exact repetition of chlorine but the very similar body bromine, and when the same position recurs for the third time we see iodine. I need not multiply examples. I may, however, point out that we have here a phenomenon which reminds us of alter- nating or cyclical generation in the organic world, or we may perhaps say of atavism, a recurrence to ancestral types, somewhat modified. In this evolutionary scheme it cannot be expected that the potential elements should all be equal to each other. On the con- trary, many degrees of stability will be represented, and if we look with a scrutinising eye we shall see our old friend the " missing link," coarse enough to be detected in the groups comprising such bodies as iron, nickel, and cobalt ; palladium, ruthenium, and rhodium ; iridium, osmium, and platinum : whilst in a more subtile form these missing links present themselves as representatives of the diifcrences which I have suggested between the atoms of the same chemical element. On the even or paramagnetic half of the swing the energy appears to have acted in a very irregular manner, whilst on the odd, or diamagnetic half, there is considerable regularity. Thus, be- tween the extreme odd elements, silicon (28), germanium (73), tin (118), a missing element (163), and lead (208) there is a diiier- ence of exactly 45 units, rendering this half of the curve remarkably symmetrical. On the even side the differences are 36, 42, 61, 39 and 53 (assuming an atomic weight of 180 for a missing element between cerium and thorium). At first sight these differences appear to follow no law, but they gain interest when we see that the mean differences of these figures is 44*2 — almost exactly the same as that on the odd side of the curve. From this uniformity of difference — actual on the one side and average on the other — we may fairly infer that whilst on the odd side there has been little or no variation in the force symbolised by the ver- tical line, minor irregularities have been the rule on the even side. Or, in other words, the fall of temperature has been very uniform on the odd side — where, accordingly, we see that every original element represents a well marked group, sodium, magnesium, aluminium, silicon, j^hosphorus, and chlorine ; whilst on the even side the tem- perature has fallen with considerable fluctuations, thus preventing the formation here of any well-marked groups of elements, excepting those of w^hich lithium and glucinum are the leading types. Having thus detected irregularities in the fall of temperature in the protyle, we may next ask is there any fluctuation in the force re- presented by the pendulum-movement ? This movement I have assumed to be connected with electrical energy. The earliest-formed elements are those in which chemical energy is at a maximum ; as 1887.] on Genesis of the Elements. 69 we descend the scale the affinities become feebler and the chemism grows more and more sluggish. In part this change may be due to the circumstance that the elements generated at a reduced tempera- ture no longer possess great molecular mobility. But it is also ex- tremely probable that the chemism-forming energy is itself dying out like the fires of the cosmic furnace. I have attempted to sym- bolise this gradual fading by a decrease in the amplitude of vibration. The figures representing the scale of atomic weights may be sup- posed to represent, inversely, the scale of a gigantic pyrometer plunged into a cauldron where the elements of suns and worlds are undergoing formation. As the heat sinks, the elements generated increase in density and atomic weight. Below the formation-point of uranium the temj^erature will probably i3ermit of the earlier-born elements forming combinations among themselves, and we shall witness, e. g. the birth of water, and the formation of those known compounds the dissociation of which is not beyond the powers of our terrestrial sources of heat. Turning to the upper portion of the diagram we see that there is little room for elements of a lower atomic weight than hydrogen. But let us pass " through the looking-glass " and cross the zero line. What shall we find on the other side ? Dr. Carnelley asks for an element of negative atomic weighf ; and here is ample room and verge enough for a shadow series of such unsubstantialities, leading, perhaps, to that " Unseen Universe " which two eminent physicists have discussed. Helmholtz says that electricity is probably as atomic as matter ;* is electricity one of the negative elements ? and the luminiferous ether another ? Matter, as we now know it, does not here exist ; and the forms of energy which are aj^parent in the motions of matter are as yet only latent possibilities. A genesis of the elements such as is here sketched would not be confined to our little solar system, but would probably follow the same general sequence of events in every centre of energy now visible as a star. It may be said that so far I have proved nothing. But I may submit that at least I have shown the improbability of the per- sistence of the ultimate character, and the eternal self-existence, the fortuitous origin, and the simultaneous creation of the elements. The analogy of these elements with the organic radicles, and still more with living organisms, constrains us to suspect that they are compound bodies, springing from a process of evolution. We have drawn corroborative evidence from the distribution and the associa- tion of the rare earths, evidence which seems to be converging to the * " If we accept the hypothesis that the elementary substances are composed of atoms, we cannot avoid concluding that electricity also, positive as well as negative, is divided into definite elementary portions, which behave like atoms of electricity."— Helmholtz, Faraday Lecture, 1881. 60 Mr. W. Crookes on Genesis of the Elements. [Feb. 18, point of assuming a direct character. Led by the great law of con- tinuity I have ventured to suggest a process by which our elements may have been originated. I dare not say must have been originated, for no one can be better aware than I am how much remains to be done before this great, this fundamental question can be finally solved. I earnestly hope that others will take up the task, and that chemistry, like biology, may find its Darwin. If we consider the position we occupy with reference to the primary questions of chemistry, we might compare research to a game of chess. Man, the investigator, is playing, not with Satan for his soul, but with Nature for knowledge and power. Each element has its allotted moves on the great board of the universe ; some of them dependent solely on themselves, and others on the interaction of the adjacent elements. Some of our elements may be compared to pawns, others to knights, bishops, or castles. The game is fearfully unequal. Our antagonist knows the power and the limitations of every piece, all the laws of the game, all possible moves, and is merciless in exacting j)enalty for errors. We experimentalists know nothing but Ts^hat we have learned in countless losing games. But our knowledge is increasing. Nature no longer gives us fool's mate. The struggle becomes more obstinate, more exciting, we come upon new gambits, new combinations, and though still checkmated at the last, we take a few pawns, jierhaps even a piece or two. Such partial successes were achieved when Lavoisier introduced the use of the balance and developed the theory of combustion ; when Dalton put forward the atomic theory ; when Davy decomposed the alkalies ; when Wohler effected the synthesis of urea ; and when Faraday first liquefied a gas. On such and many similar occasions I can imagine our antagonist becoming thoughtful. But suj)pose we one day win the game ; that we find out what these obstinate elements really are, that we learn how they came into being, and wherefore their number, their j^roperties, and their mutual relations are such as we find them ? We shall then know, a priori, what w^e have now to find out by special experiment ; we shall foresee the results of every conceivable reaction, and our theories will legitimate themselves by the power of prediction. To attain such knowledge seems to me the grand task of the chemistry of the coming age. If you think I have given too free rein to the " scientific imagina- tion " you will, I hope, forgive me as one who at least does not despair of the future of our Science. [W. C] 1887.] Captain W. de W. Ahney on Sunlight Colours. 61 WEEKLY EVENING MEETING, Friday, February 25, 1887. William Huggins, Esq. D.C.L. LL.D. F.R.S. Manager and Vice- President, in the Cliair. Captain W. de W. Abney, R.E. F.R.S. 3LB.L Sunlight Colours. Sunlight is so intimately woven np with our physical enjoyment of life that it is perhaps not the most uninteresting subject that can be chosen for what is — perhaps somewhat pedantically — termed a Friday evening " discourse." Now, no discourse ought to be possible without a text on which to hang one's words, and I think I found a suitable one when walking with an artist friend from South Kensington Museum the other day. The sun appeared like a red disk through one of those fogs which the east wind had brought, and I hajtpened to point it out to him. He looked, and said, " Why is it that the sun appears so red ? " Being near the^ railway station, whither he was bound, I had no time to enter into the subject, but said if he would come to the Royal Institution this evening I would endeavour to explain the matter. I am going to redeem that promise, and to devote at all events a portion of the time allotted to me in answering the question why the sun appears red in a fog. I must first of all appeal to what every one w^ho frequents this theatre is so accustomed to, viz. the spectrum ; I am going not to put it in the large and splendid stripe of the most gorgeous colours before you with which you are so well acquainted, but my spectrum will take a more modest form of 23urer colours some twelve inches in length. I w^ould ask you to notice which colour is most luminous. I think that no one will dispute that in the yellow we have the most intense luminosity, and that it fades gradually in the red on the one side and in the violet on the other. This then may be called a quali- tative estimate of relative brightnesses ; but I wish now to introduce to you what was novel last year, a quantitative method of measuring the brightness of any part. Before doing this I must show you the diagram of the apparatus which I shall employ in some of my experiments. R R are rays (Fig. 1) coming from the arc light, or, if we were using sunlight, from a heliostat, and a solar image is formed by a lens, Li,on the slit Sj of the collimator c. The parallel rays proluced by the lens l^ are partially refracted and partially reflected. The former pass through the prisms PiPo, and are focused to form a spectrum by 62 Captain W. cle W. Ahney [Feb. 25, a lens, L3, on d, a movable ground-glass screen. The rays are collected by a lens, l^, tilted at an angle as shown, to form a white image of the near surface of the second j)rism on p. Passing a card with a narrow slit S2, cut in it in front of the spectrum, any colour which I may require can be isolated. The consequence is that, instead of the white patch upon the screen, I Fig. 1, ^ Ls ^ Li Colour Photometer. have a coloured patch, the colour of which I can alter to any hue lying between the red and the violet. Thus, then, we are able to get a real patch of very appropriately homogeneous light to work with, and it is with these patches of colour that I shall have to deal. Is there any way of measuring the brightness of these patches ? was a question asked by General Festing and myself. After trying various plans, we hit upon the method I shall now show you, and if any one works with it he must become fascinated with it on account of its almost childish simplicity — a simplicity, I may remark, which it took us some months to find out. Placing a rod before the screen, it casts a black shadow surrounded with a coloured background. Now I may 1887.] on Sunlight Colours. 63 cast another shadow from a candle or an incandescence lamp, and the two shadows are illumiuated, one by the light of the coloured patch and the other by the light from an incandescence lamp which I am using to-night. [Shown,] Now one stripe is evidently too dark. By an arrangement which I have of altering the resistance interj^osed between the battery and the lamp, I can diminish or increase the light from the lamp, first making the shadow it illuminates too light and then too dark compared with the other shadow which is illuminated by the coloured light. Evidently there is some position in which the shadows are equally luminous. When that point is reached, I can read off the current which is passing through the lamp, and having previously standardised it for each increment of current, I know what amount of light is given out. This value of the incandescence lamp I can use as an ordinate to a curve, the scale number which marks the position of the colour in the spectrum being the abscissa. This can be done for each part of the spectrum, and so a complete curve can be constructed which we call the illumination curve of the sj)ectrum of the light under consideration. Now, when we are working in the laboratory with a steady light, we may be at ease with this method, but when we come to working with light such as the sun, in which there may be constant variation owing to passing, and maybe usually imperceptible, mist, we are met with a difficulty; and in order to avoid this, General Festing and myself substituted another method, which I will now show you. We made the comparison light part of the light we were measuring. Light which enters the collimating lens partly passes through the jDrisms and is partly reflected from the first surface of the prism ; that we utilise, thus giving a second shadow. The reflected rays from Pi fall on g, a silver-on-glass mirror. They are collected by L5, and form a white image of the prism also at f. The method we can adopt of altering the intensity of the comparison light is by means of rotating sectors, which can be opened or closed at will, and the two shadows thus made equally luminous. [Shown.] But although this is an excellent plan for some purposes, we have found it better to adopt a different method. You will recollect that the brightest part of the spectrum is in the yellow, and that it falls off in brightness on each side, so, instead of opening and closing the sectors, they are set at fixed intervals, and the slit is moved in front of the spectrum, just making the shadow cast by the reflected beam too dark or too light, and oscillating between the two till equality is dis- covered. The scale number is then noted, and the curve con- structed as before. It must be remembered that, on each side of the yellow, equality can be established. This method of securing a comparison light is very much better for sun work than any other, as any variation in the light whose spectrum is to be measured aflects the comparison light in the same degree. Thus, suppose I interpose an artificial cloud before the slit of the spectroscope, having adjusted the two shadows, it will be seen 64 • Ca2)tam W. de W. Ahney [Feb. 25, that the passage of steam in front of the slit does not alter the relative intensities ; but this result must be received with caution. [The lecturer then proceeded to point out the contrast colours that the shadow of the rod illuminated by white light assumed.] I must now make a digression. It must not be assumed that every one has the same sense of colour, otherwise there would be no colour-blindness. Part of the researches of General Testing and myself have been on the subject of colour-blindness, and these I must briefly refer to. We test all who come by making them match the luminosity of colours with white light, as I have now shown you ; and as a colour-blind person has only two fundamental colour per- ceptions instead of three, his matching of luminosities is even more accurate than is that made by those whose eyes are normal or nearly normal. It is curious to note how many people are more or less deficient in colour-perception. Some have remarked that it is impossible that they were colour-blind, and would not believe it, and sometimes we have been staggered at first with the remarkable manner in which they recognised colour to which they ultimately proved deficient in perception. For instance, one gentleman when I asked him the name of a red colour patch, said it was sunset colour ; he then named green and blue correctly, but when I reverted to the red patch he said green. On testing further he proved totally defi- cient in the colour-perception of red, and with a brilliant red patch he matched almost a black shadow. The diagram shows you the relative perceptions in the sj)ectrum of this gentleman and myself. There are others who only see three-quarters, others half, and others a quarter the amount of red that we see, whilst some see none. Others see less green and others less violet, but I have met with no one that can see more than myself or General Festiug, whose colour-perceptions are almost identical. Hence we have called our curve of illumination the " normal curve." We have tested several eminent artists in this manner, and about one-half of the number have been proved to see only three-quarters of the amount of red which we see. It might be thought that this would vitiate their powers of matching colour, but it is not so. They paint what they see, and although they see less red in a subject, they see the same deficiency in their pigments ; hence they are correct. If totally deficient, the case of course would be different. Let us carry our experiments a step further, and see what effect what is know^n as a turbid medium has upon the illuminating value of difierent parts of the spectrum. I have here water which has been rendered turbid in a very simple manner. In it has been very cautiously dropped an alcoholic solution of mastic. Now^ mastic is practically insoluble in water, and directly the alcoholic solution comes in contact with the w^ater it separates out in very fine particles, which, from their very fineness, remain suspended in the water. I propose now to make an experiment with this turbid water. I place a glass cell containing water in front of the slit, and on 1887.] on Sunlight Colours. 65 the screen I throw a patch of blue light. I now change it for turbid water in a cell. This thickness much dims the blue ; with a still greater thickness the blue has almost gone. If I measure the intensity of the light at each operation, I shall find that it diminishes according to a certain law, which is of the same nature as the law of absorption. For instance, if one inch diminishes the light one-half, the next will diminish it half of that again, the next half of that again, whilst the fourth inch will cause a final diminution of the total light of one-sixteenth. If the first inch allows only one-quarter of the light, the next will only allow one-sixteenth, and the fourth inch will only permit 1/256 part to pass. Let us, however, take a red patch of light and examine it in the same way. We shall find that, when the greater thickness of the turbid medium we used when examining the blue patch of light is placed in front of the slit, much more of this light is allowed to pass than of the blue. If we measure the light we shall find that the same law holds good as before, but that the proportion which passes is invariably greater with the red than the blue. The question then presents itself: Is there any connection between the amounts of the red and the blue which pass ? Lord Rayleigh, some years ago, made a theoretical investigation of the subject ; but, as far as I am aware no definite experimental proof of the truth of the theory was made till it was tested last year by General Testing, and myself. His law was that for any ray, and through the same thickness, the light transmitted varied inversely as the fourth power of the wave-length. The wave- length 6000 lies in the red, and the wave-length 4000 in the violet. Now 6000 is to 4000 as 3 to 2, and the fourth powers of these wave- lengths are as 81 to 16, or as about 5 to 1. If, then, the four inches of our turbid medium allowed three-quarters of this particular red ray to be transmitted, they would only allow ( j)^, or rather less than one-fourth, of the blue ray to pass. Now this law is not like the law of absorption for ordinary absorbing media, such as coloured glass for instance, because here we have an increased loss of light running from the red to the blue, and it matters not how the medium is made turbid, whether by varnish, suspended sulphur, or what not. It holds in every case, so long as the particles which make the medium turbid are small enough; and please to recollect that it matters not in the least whether the medium which is rendered turbid is solid, liquid, or air. Sulphur is yellow in mass, and mastic varnish is nearly white, whilst tobacco-smoke when condensed is black, and very minuto particles of water are colourless : it matters not what the colour is, the loss of light is always the same. The result is simply due to the scattering of light by fine particles, such particles being small in dimensions compared with a wave of light. Now, in this trough is suspended 1/1000 of a cubic inch of mastic varnish, and the water in it measures about 100 cubic inches, or is 100,000 times more in bulk than the varnish. Under a microscope of ordinary power it is impossible to distinguish any particles of varnish : it looks like a Vol. XII. (No. 81.) f 66 Captain W. de W. Ahney [Feb. 25, homogeneous fluid, though we know that mastic will not dissolve in water. Now a wave-length in the red is about 1/40,000 of an inch, and a little calculation will show that these particles are well within the necessary limits. Prof. Tyndall has delighted audiences here with an exposition of the effect of the scattering of light by small particles in the formation of artificial skies, and it would be super- fluous for me to enter more into that. Suffice it to say that when particles are small enough to form the artificial blue sky they are fully small enough to obey the above law, and that even larger particles will suffice. We may sum up by saying that very fine particles scatter more blue light than red light, and that consequently more red light than blue light passes through a turbid medium, and that the rays obey the law prescribed by theory. I will exemplify this once more by using the whole spectrum and placing this cell, which contains hyposulphite of soda in solution in water, in front of the slit. By dropping in hydrochloric acid, the sulphur separates out in minute particles ; and you will see that, as the particles increase in number, the violet, blue, green, and yellow disappear one by one and only red is left, and finally the red disappears itself. Now let me revert to the question why the sun is red at sunset. Those who are lovers of landscape will have often seen on some bright summer's day that the most beautiful effects are those in which the distance is almost of a match to the sky. Distant hills which when viewed close to are green or brown, when seen some five or ten miles away appear of a delicate and delicious, almost of a cobalt, blue colour. Now, what is the cause of this change in colour ? It is simply that we have a sky formed between us and the distant ranges, the mere outline of which looms through it. The shadows are softened so as almost to leave no trace, and we have what artists call an atmospheric effect. If we go into another climate, such as Egypt or amongst the high Alps, we usually lose this effect. Distant mountains stand out crisp with black shadows, and the want of atmosphere is much felt. [Photographs showing these differences were shown.] Let us ask to what this is due. In such climates as England there is always a certain amount of moisture present in the atmosphere, and this moisture may be present as very minute particles of water — so minute indeed that they will not sink down in an atmosphere of normal density — or as vapour. When present as vapour the air is < much more transparent, and it is a common expression to use, that when distant hills look " so close " rain may be expected shortly to follow, since the water is present in a state to precipitate in larger particles ; but when present as small particles of water the hills look very distant, owing to what we may call the haze between us and them. In recent weeks every one has been able to see very multiplied effects of such haze. The ends of long streets, for instance, have been scarcely visible though the sun may have been shining, and at night the long vistas of gas lamps have shown light having an in- creasing redness as they became more distant. Every one admits the 1887/ on Sunlight Colours. 67 presence of mist on these occasions, and this mist must be merely a collection of intangible and very minute particles of suspended water. In a distant landscape we have simply the same or a smaller quantity of street-mists occupying, instead of perhaps 1000 yards, ten times that distance. Now I would ask, What effect would such a mist have upon the light of the sun which shone through it 9 It is not in the bounds of present possibility to get outside our atmosphere and measure by the plan I have described to you the different illuminating values of the different rays, but this we can do : — First, we can measure these values at different altitudes of the sun, and this means measuring the effect on each ray after passing through different thicknesses of the atmosphere, either at different times of day, or at different times of the year, about the same hour. Second, by taking the instrument up to some such elevation as that to which Langley took his bolometer at Mount Whitney, and so to leave the densest part of the atmosphere below us. Now, I have adopted both these plans. For more than a year I have taken measure- ments of sunlight in my laboratory at South Kensington, and I have also taken the instrument up to 8000 feet high in the Alps, and made observations there, and with a result which is satisfactory in that both sets of observations show that the law which holds with artifi- cially turbid media is under ordinary circumstances obeyed by sunlight in passing through our air : which is, you will remember, that more of the red is transmitted than of the violet, the amount of each de- pending on the wave-length. The luminosity of the spectrum observed Fig. 2. Relative Luminosities. at the Eiffel I have used as my standard luminosity, and compared all others with it. The result for four days you see in the diagram. F 2 68 Oqyfain W. de W. Ahneij [Feb. 25, I have diagrammatically shown the amount of different colours which penetrated on the same days, taking the Eiffel as ten. It will be seen that on December 23 we have really very little violet and less than half the green, although we have four-fifths of the red. The next diagram before you shows the minimum loss of light which I have observed for different air thicknesses. On the top we Fig. 3. ^AlUtude) 8o'o of A Se/i tys. '^J\roo, Tlb^" -^ *>M-^ ^ 1 .6 ^.se^^rj y. ^ .^m^. ^nO^^-^ -^^ C^ 2. ■ i- 0 1 Blue^ Gf •een YeUi. 1 Tied Proportions of Transmitted Colours. have the calculated intensities of the different rays outside our atmosphere. Thus wc have that through one atmosphere, and two, three, and four ; and you will see what enormous absorption there is in the blue end at four atmospheres. The areas of these curves, which give the total luminosity of the light, are 761, 662, 577, 503, and 439 ; and if observed as astronomers observe the absorption of light, by means of stellar observations, they would have had the values, 761, 664, 578, 504, and 439 — a very close approximation one to the other. Next notice in the diagram that the top of the curve gradually inclines to go to the red end of the spectrum as you get the light transmitted through more and more air, and I should like to show you that this is the case in a laboratory experiment. Taking a slide with a wide and long slot in it, a portion is occupied by a right- angled prism, one of the angles of 45° being towards the centre of the slot. By sliding this prism in front of the spectrum I can deflect outwards any portion of the spectrum I like, and by a mirror can reflect it through a second lens, forming a patch of light on the screen overlapping the patch of light formed by the undeflected rays. If the two patches be^xactly equal, white light is formed. Now, by placing a rod as before in front of the patch, I have two coloured stripes in a white field, and though the background remains of the same intensity of white, the intensities of the two stripes can be altered by moving 1887.] Oil Sunlight Colours. 69 the right-angled prism through the spectrum. The two stripes are now apparently equally luminous, and I see the point of equality is where the edge of the right-angled prism is in the green. Placing a narrow cell filled with our turbid medium in front of the slit, I find that the equality is disturbed, and I have to allow more of the yellow to come into the patch formed by the blue end of the spectrum, and consequently less of it in the red end. I again establish equality. Placing a thicker cell in front, equality is again disturbed, and I have to have less yellow still in the red half, and more in the blue half. I now remove the cell, and the inequality of luminosity is still more glaring. This shows, then, that the rays of maximum luminosity must travel towards the red as the thickness of the turbid medium is increased. The observations at 8000 feet, here recorded, were taken on September 15 at noon, and of course in latitude 46"^ the sun could not be overhead, but had to traverse what would be almost exactly equivalent to the atmosphere at sea-level. It is much nearer the calculated intensity for no atmosj)here intervening, than it is for one atmosphere. The explanation of this is easy. The air is denser at sea-level than at 8000 feet up, and the lower stratum is more likely to hold small water particles or dust in suspension than is the higher. For, however small the particles may be, they will have a greater tendency to sink in a rare air than in a denser one, and less water vapour can be held per cubic foot. Looking, then, from my laboratory at South Kensington, we have to look through a propor- tionately larger quantity of suspended particles than we have at a high altitude when the air thicknesses are the same ; and consequently the absorption is proportionately greater at sea-level than at 8000 feet high. This leads us to the fact that the real intensity of illumina- tion of the difierent rays outside the atmosphere is greater than it is calculated from observations near sea-level. Prof. Langley, in this theatre, in a remarkable and interesting lecture, in which he de- scribed his journey up Mount Whitney to about 12,000 feet, told us that the sun was really blue outside our atmosphere, and at first blush the amount of extra blue which he deduced to be present in it would, he thought, make it so; but though he surmised the result from experiments made with rotating disks of coloured paper, he did not, I think, try the method of using pure colours, and consequently, I believe, slightly exaggerated the blueness which would result. I have taken Prof. Langley's calculations of the increase of intensity for the difi'erent rays, which I may say do not quite agree with mine, and I have prepared a mask which I can place in the spectrum giving the different proportions of each ray as calculated by him, and this when placed in front of the spectrum will show you that the real colour of sunlight outside the atmosjohere, as calculated by Langley, can scarcely be called bluish. Alongside I place a patch of light which is very closely the colour of sunlight on a July day at noon in England. This comparison will enable you to gauge the blueness, 70 Captain W. de W. Ahney [Feb. 25, and you will see that it is not very blue, and, in fact, not bluer per- ceptibly than that we have at the Riffel, the colour of the sunlight at which place I show in a similar way. I have also j^repared some screens to show you the value of sunlight after passing through five and ten atmospheres. On an ordinary clear day you will see what a yellowness there is in the colour. It seems that after a certain amount of blue is present in white light the addition of more makes but little difference in the tint. But these last patches show that the light which passes through the atmosphere when it is feebly charged with particles does not induce the red of the sun as seen through a fog. It only requires more suspended particles in any thickness to induce it. In observations made at the Riffel, and at 14,000 feet, I have found that it is possible to see far into the ultra-violet, and to dis- tinguish and measure lines in the sun's spectrum which can ordina- rily only be seen by the aid of a fluorescent eye-piece or by means of photography. Circumstantial evidence tends to show that the burning of the skin, which always takes place in these high altitudes in sunlight, is due to the great increase in the ultra-violet rays. It may be remarked that the same kind of burning is effected by the electric arc light, which is known to be very rich in these rays. Again, to use a homely phrase, " You cannot eat your cake and have it." You cannot have a large quantity of blue rays present in your direct sunlight, and have a luminous blue sky. The latter must always be light scattered from the former. Now, in the high Alps you have, on a clear day, a deep blue-black sky, very different indeed from the blue sky of Italy or of England ; and as it is the sky which is the chief agent in lighting up the shadows, not only in those regions do we have dark shadows on account of no intervening — what I will call — mist, but because the sky itself is so little luminous. In an artistic point of view this is important. The warmth of an English landscape in sunlight is due to the highest lights being yellowish, and to the shadows being bluish from the sky-light illuminating them. In the high Alps the high lights are colder, being bluer, and the shadows are dark, and chiefly illuminated by reflected direct sunlight. Those who have travelled abroad will know what the efi'ect is. A painting in the Alps, at any high elevation, is rarely pleasing, although it may be true to Nature. It looks cold, and somewhat harsh and blue. In London we are often favoured with easterly winds, and these, unpleasant in other ways, are also destructive of that portion of the sunlight which is the most chemically active on living organisms. The sunlight composition of a July day may, by the prevalence of an easterly wind, be reduced to that of a November day, as I have proved by actual measurement. In this case it is not the water particles which act as scatterers, but the carbon particles from the smoke. Knowing, then, the cause of the change in the colour of sunlight, we can make an artificial sunset, in which we have an imitation light 1887.] on Sunlight Colours. 71 passing through increasing thicknesses of air largely charged with water particles. [The image of a circular diaphragm placed in front of the electric light was thrown on the screen in imitation of the sun, and a cell containing hyposulphite of soda placed in the beam. Hydrochloric acid was then added : as the fine particles of sulphur were formed, the disk of light assumed a yellow tint, and as the decomposition of the hyposulphite progressed, it assumed an orange and finally a deep red tint.] With this experiment I terminate my lecture, hoping that in some degree I have answered the question I propounded at the outset : why the sun is red when seen through a fog. [W. DE W. A.] 72 Mr. V. Horsleff on Brain Surgery in the Stone Ages, [March 4, WEEKLY EVENING MEETING, Friday, March 4, 1887. Sir William Bowman, Bart. LL.D. F.R.S. Manager and Vice- Presidentj in the Chair. Victor Horsley, Esq. F.R.S. B.S. F.R.C.S. Brain Surgery in the Stone Ages. The title of this discourse fairly expressed its scope, for the practice by the people of the neolithic period of resorting to surgery for the relief of mischief to the brain was fully detailed. It seemed scarcely necessary to do more than briefly refer to the gradual advance of civilisation through the stages of stone, bronze, and iron ; but it was pointed out that while the Greeks at the time of their siege of Troy had only half learnt how to use iron, the northern nations of Europe were still in the stone period. Neither did it appear necessary to do more than briefly allude to the general habits of neolithic people, save to draw attention to the fact, that whatever be its explanation, the instances in which trephining was practised in the stone age occur more frequently in the centre of France than anywhere else in Europe. The deliberate nature of the operation, as exemplified in the skulls hitherto discovered, was proved by the position of the openings, their being in the majority of instances healed, and by the extremely interesting discovery of the fact that the portions of bone cut out were not only preserved as amulets, but also put back again into such a trephined head at the time of death. From a comparison of the modes of trephining per- formed by savage and mediaeval nations, it was proved that the stone age people opened the skull either by drilling, scraping, or sawing, most probably by the last method. Similarly it was shown from a study of the seat of operation, that in all probability recourse to surgery was suggested by the symptoms of depressed fracture, and notably by the symptoms of traumatic epilepsy. 1887.] General Monthly Meeting, 73 GENEKAL MONTHLY MEETING, Monday, March 7, 1887. Henry Pollock, Esq. Treasurer and Vice-President, in the Chair. Gerrard Ansdell, Esq. F.C.S. Alexander Thomas Binny, Esq. Mrs. Amelia Coles, Eugene H. Cowles, Esq. Samuel Fenwick, M.D. Edwin Freshfield, Esq. LL.D. V.P.S.A. Edward Kraftmeier, Esq. Thomas Hayter Lewis, Esq. F.S.A. Captain Andrew Noble, C.B. F.E.S. Charles M. Eoupell, Esq. M.A. Major Ricarde Seaver, Sir Henry Mervyn Vavasour, Bart. Major-General Edmond Walker, E.E. were elected Members of the Eoyal Institution. A Letter was read to His Grace The President from Sir Frederick Abel, Organising Secretary to the Imperial Institute, dated February 4, 1887, requesting the co-operation of the Royal Institution in the promotion of the^ establishment of the Imperial Institute. The Chairman described the course which the Managers propose to adopt in efifecting this co-operation, and stated that Subscriptions for the Imperial Institute would be received at the Royal Institution, and a List of such Subscriptions suspended in the Hall. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM Academia dei Lincei, Reale, Roma — Atti, Serie Quarta: Eendiconti. Vol. II. 2° Semestre, Fasc. 12 ; Vol. III. Fasc. 1, 2. 8vo. 1886-7. Asiatic Society of Bengal — Journal, Vol. LV. Part 1, No. 3 ; Part 2, No. 3. 8vo. 1886. Proceedings, 1886, Nos. 8, 9. 8vo. Asiatic Society, Eoyal (Bombay Branch) — Index to the Transactions of the Literary Society of Bombay, Vol. I.-III. and to the Journals, Vol. I.-XVII. 8vo. 1886. Astronomical Society, Royal — Monthly Notices, Vol. XLVII. No. 3. 8vo. 1887. Bankers, Institute of — Journal, Vol. VIII. Part 2. 8vo. 1887. British Architects, Royal Institute of — Proceedings, 1886-7, Nos. 8, 9. 4to. Canada, Geological and Natural History Survey of — Annual Keport, 1885. With Maps. 8vo. 1886. Cliemieal Society— J onrna\ for February, 1887. 8vo, Civil Engineers' Institution — Minutes of Proceedings, Vol. LXXXVlL 8vo. 1886-7. Crisp, Frank, Esq. LL.B. F.L.S. &c. M.R.I, (the Editor)— Jomiml of the Eoyal Microscopical Society, 1887, Part 1. 8vo. 74 General Monthly Meeting. [March 7, Dawson and Sons, Messrs. W. — J. A. Berly's Universal Electrical Directory. 8vo. 1887. Despeissis, M. L. H. — La Ste'no-Telegraphie. Par M. G. A. Cassagnes. 4to. 1886. Editors— AmencQ.n Journal of Science for February, 1887. 8vo. Analyst for February, 1887. 8vo, Athenseum for February, 1887. 4to. Chemical News for February, 1887. 4to. Chemist and Druggist for February, 1887. 8vo. Engineer for February, 1887. fol. Engineering for February, 1887. fol. Horological Journal for February, 1887. 8vo. Industries for February, 1887. fol. Iron for February, 1887. 4to. Nature for February, 1887. 4to. Eevue Scientifique for February, 1887. 4to. Telegraphic Journal for February, 1887. 8vo. Zoophilist for February, 1887. 4to. Florence, Bihlioteca Nazionale Centrale — BoUetino, Num. 26. 8vo. 1887. FranMin Institute — Journal, No. 734. 8vo. 1887. Geographical Society, i?o?/aZ— Proceedings, New Series, Vol. IX. Nos. 2, 3. 8vo. 1887. Supplementary Papers, Vol. II. No. 1. 8vo. 1887. Geological Society — Quarterly Journal, No. 169. 8vo. 1887. Historical Society, Royal — Transactions, New Series, Vol. III. Parts 3 and 4. 8vo. 1886. Johns Hopkins University — Studies in Historical and Political Science, Fifth Series, No. 3. 8vo. 1887. University Circular, No. 55. 4to. 1887. Manchester Geological Society — Transactions, Vol. XIX. Parts 3, 4. 8vo. 1887. Marks, William D. Esq. (the Author) — Limitations of the Expansion of Steam. 8vo. 1887. Meteorological Office — Monthly Weather Eeport for July-Aug. 1886. 4to. Meteorological Observations at Stations of the Second Order, 1882. 8vo. 1887. Hourly Readings, 1883, Part 4 ; 1884, Part 2. 4to. 1886-7. Ministry of Public Works, Borne — Giornale del Genio Civile, Serie Quarta, Vol. VI. Nos. 11, 12. 8vo. And Disegni. fol. 1886. North of England Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVI. Part 1. 8vo. 1887. Numismatic Society — Chronicle and Journal, 1886, Part 4, 8vo. Odontological Society of Great Britain — Transactions, Vol. XIX. No. 3. New Series. 8vo. 1887. Pharmaceutical Society of Great Britain — Journal, February. 1887. 8vo. Calendar. 8vo. 1887. Photographic Society — Journal, New Series, Vol. XI. No. 4. 8vo. 1887. Physical Society of London — Proceedings, Vol. VIII. Part 3. 8vo. 1887. Eoyal Society of London — Proceedings, No. 250. 8vo. 1886. Royal Society of New South Wales — Journal and Proceedings, Vol. XIX. 8vo. 1886. St. Bartholomeiv's Hospital— Re^orta, Vol. XXII. 8vo. 1886. Society of Arts — Journal, February, 1887. 8vo. Statistical Society— J omnol, Vol. XLIX. Part 4. 8vo. 1886. St. Petershourg, Academic des Sciences — M.6mo\ies, Tome XXXIV. Nos. 7-11. 4to. 1886. Vereins zur Beforderung des Gewerhfleisses in Preussen — Verhandlungen, 1887: Heft, 1. 4to. Wild, Dr. H. (the Director)— Annalen. des Physikalischen Central Observa- toriums, 1885. 4to. 1886. 1887.] Archd. Farrar on Society in the Fourth Century after Christ. 75 WEEKLY EVENING MEETING, Friday, March 11, 1887. Henry Pollock, Esq., Treasurer and Vice-President, in the Chair. The Ven. Archdeacon Farrar, M.A. D.D. F.R.S. Society in the Fourth Century after Christ. After a brief sketch of the fourth century in its varied and strik- ing elements of life, and the great leaders of religious thought whom it produced, the lecturer proceeded to mention some of its broad general characteristics. 1. It was an age of great calamities, in which men suffered from war, pestilence, famine, and the incursions of barbarians. The sack of Rome affected the civilised world like the shock of an earthquake. The news of it fell with stunning force on the mind of St. Jerome, in his cave at Bethlehem, and if St. Augustine was less deeply moved by it, and felt chiefly concerned to prove that the catastrophe was not the consequence of Christianity, the reason was that he was chiefly interested in the City of God, while the City of Evil was left to its predestined ruin. 2. The highest no less than the lowest orders of society were affected by these calamities. The age was full of " strange stories of the deaths of kings." There was scarcely a single Emperor or usurper of the century who did not perish by murder, suicide, or execution, and the presentiment of Julian was justified, who, on first putting on the Imperial purple, exclaimed, rhv 5e /far' oace €AA.a)3e iroptpvpios Odvaros Koi /xoTpa KpaTnir). Or, as Chapman renders it, " Death with his purple finger shut, and violent fate his eyes." 3. Yet the Emperors were surrounded with that elaborate pomp and circumstance which we call Byzantinism. Constantino's cruelty, and his passion for jewels, suggested the stinging epigram, " Saturni aurea ssecla quis requirat ? Sunt hsec gemmea, sed Neroniana ! " The court was filled with pompous ceremonies and slavish officialism. The title " Your Eternity " was just beginning to come into fashion, when it was scoffed out of court by St. Athanasius. By way of illustration, a description was given of one of the splendid summer processes of the Emperor Arcadius. Yet the Emperors were often slaves to their own eunuchs. 4. This age of calamity was also an age of boundless luxury, of 76 Archdeacon Farrar [March 11, which details were'given from the Homilies of St. Chrysostom, and the History of the Pagan soldier Ammianus Marcellinus. 5. The luxury flaunted itself side by side with the most grind- ing poverty. The general misery of the tax-crushed multitude was illustrated by anecdotes from Palladius, St. Chrysostom, St. Basil, and St. Ambrose. 6. The fourth century was also an age of struggling beliefs, in which many guided their professions exclusively by considerations of social and political expediency. 7. The combination of circumstances thus illustrated led to an ever deepening superstition both among Pagans and Christians. The Pagan spirit of superstition was illustrated by stories from the sophist Eunapius, and by the wild outburst of panic against the use of sorcery in the days of Valens— a panic which closely resembled the frantic state of suspicion prevalent in the days of the Popish plot. The superstitious spirit of Christians was evinced by the adoration paid to very dubious relics, and by the credulous acceptance of the most portentous miracles, as shown in the biogra- phies of St. Martin of Tours, St. Gregory Tbaumaturgus, and others. 8. Yet, amid all these superstitions and catastrophes, the quiet everyday beautiful life of humanity was going on, as was shown by peaceful pictures of the sweet Christian homes in which men like St. Gregory of Nazianzus, St. Basil, and St. Chrysostom in the East, and St. Ambrose in the West, were trained to usefulness and self-devotion. 9. The lecturer proceeded to furnish various illustrations of the life of the young. He gave anecdotes of the boyhood of St. Augustine ; of the pranks played by students in the days of St. Gregory of Nazianzus in the University of Athens ; of the rite of mock initiation known as " the Bath " ; of the Professor Proaeresius and the boy-student Eunapius. 10. Some account was also given of the varied experiences of St. Augustine as a Professor of Rhetoric at Carthage, Milan, and Pome ; of the turbulent young students known as the Eversores in Africa ; and of the beautiful assiduity and skill with which Augus- tine trained his young pupils, Licentius and Trygetius, in his retreat at Cassiciacum. The lecturer gave some curious and striking anecdotes of the life of a youthful law student at Rome, as illustrated in the adventures of Alypius, a friend of St. Augus- tine, who was afterwards baptised with him. 11. Details were then furnished of the life of eminent heathen sophists, and eminent Christian bishops; and it was shown from Ammianus Marcellinus, as well as from Christian writers, that pomp and prosperity exercised a very unfortunate influence on the lives and characters of many bishops in the great cities. 12. The raging party spirit and riotous slander which prevailed in this century were shown by circumstances in the lives of the great Fathers, and especially of St. Athanasius. The lecturer 1887.] on Society in (he Fourth Century after CJirist. 77 strongly enforced the lesson, taught by these narratives, of the duty of fairness and kindness in judging alike of ancient and contemporary characters. 13. The passion for theological disputation which prevailed in this century was illustrated by remarkable passages from St. Jerome and St. Augustine. 14. The lecturer then proceeded to deal with the subject of Asceticism, its extraordinary growth and strange developments, together with the disastrous effects which it produced on many minds. This part of the subject was chiefly illustrated by details derived from St. Chrysostom, St. Jerome, and Cassianus ; while from anecdotes of St. Antony (whom the lecturer, however, regarded as a purely legendary person) and St. Macarius, it was shown that even the most rigid hermits were sometimes ready to acknowledge that the ordinary course of Christian virtue might be a more excellent way than their own. In the epilogue to the lecture it was pointed out that there were many points of resemblance between the fourth century and our own, and some remarks were made on the elements which saved the civilisation of the fourth century from total destruction, and which may still be fruitful in blessings to mankind. 78 Mr. George John Romanes ^ [March 18, WEEKLY EVENING MEETING, Friday, March 18, 1887. SiE William Bowman, Bart. LL.D. F.R.S. Manager and Vice- President in the Chair. George John Romanes, Esq. M.A. LL.D. F.R.S. M.B.L Mental Differences between Men and Women* After quoting sundry representative opinions upon the subject, from Aristotle downwards, the lecturer proceeded to enumerate what appeared to him the leading features of the distinction when men and women were received as classes or en masse. The inferiority of the female mind was displayed most conspicuously in a comparative absence of originality, especially in the higher levels of intellectual work. In her powers of acquisition the woman stood nearer to the man, although even here she was behind him ; for, as soon as the age of adolescence was reached, there was a greater power of amassing knowledge on the part of the male. As musical executants, however, and also as writers of fiction, equality could be fairly asserted. With regard to judgment, the female mind was apt to take superfi- cial views, to be unduly biased from the side of the emotions, and in general to display comparative weakness. On the other hand, their greater refinement of nervous organisation led to more delicate powers of sensuous perception and rapidity of thought on the part of women. In this connexion Mr. Romanes gave the results of experiments which he had conducted on rapidity of reading, whereby it was shown that, as a rule, women could read much faster than men. Passing on to the emotions, he remarked that in women these were almost always less under control of the will than in men, being usually more volatile and displayed a greater tendency to childishness — the petty forms of resentment which belonged to a shrew or a scold, caprice, vanity, fondness of display, of social excitement, being all more characteristic of the feminine than of the masculine temperament. On the other hand, the meritorious qualities wherein the female mind stood pre-eminent were affection, sympathy, devotion, modesty, long-suffering, reverence, religious feeling, and in general the gentler virtues as distinguished from the heroic. Therefore, when a woman performed an act of heroism, the prompting motives were almost sure to be of an unselfish kind. Hence, also, it was women who first flocked in numbers to the standard of the Cross, and became followers of the religion which, by changing the whole ideal of ethics — or assigning the highest place to the gentler and domestic * A full report of the discourse is published in the 'Nineteenth Century' for May 1887. 1887.] on Mental Differences between Men and Women. 79 virtues — was destined afterwards so greatly to exalt in the estimation of man the character which belonged by nature to woman. Dealing lastly with the will^ Mr. Romanes observed that this was certainly less powerful in women than in men. We rarely found in the former that firm tenacity of purpose and determination to overcome all obstacles which was characteristic of what we called a manly mind ; and when a woman was urged to any prolonged exercise of volition, the prompting cause was usually to be found in the emotional side of her nature. Moreover, even in the lesser displays of volitional activity required for close reading, studious thought, &c., women were usually less able to concentrate their attention; and therefore they seldom specialised their pursuits to the extent usual among men. Their indecision of character often led to timidity and diffidence in adopting any line of conduct where issues of importance were concerned, thus leaving them in the painful condition, as they graphically expressed it, of " not knowing their own minds." Coming next to the causes of these mental differences between the sexes, the lecturer argued that the biological principles of selection had determined the physical superiority of male animals in general, and with it the psychological qualities of courage, self-reliance, deter- mination, and, in short, all those mental characters which belonged to a consciousness of bodily strength ; while, conversely, members of the opposite sex had acquired the opposite characters. And in the case of our own species these principles of selection further operated with a conscious reference to psychical as well as to physical endow- ments, thus acting directly as well as indirectly in severing the psychological characters of sex. Again, the maternal instincts and the prolonged association of the mother with her children in our own species imparted to her a fulness of emotional life, the whole quality of which was distinctively feminine. Thus, in accordance with the law of inheritance as limited by sex, we could understand how these influences became in successive generations cumulative ; while in the fondness of little girls for dolls we might note an interesting example in psychology of the law of inheritance at earlier periods of life. There remained but one other assignable cause of the mental differences in question. This cause was education. From the con- dition of abject slavery to which woman was consigned in the lower levels of human evolution to her condition at the present time, her mental culture had been widely different from that of man. It was not until the middle of the present century that any attempt was any- where made to provide for the higher education of women. But now, whether we liked it or not, the woman's movement was upon us, and we must endeavour to guide the flood into the most beneficial channels. What were these channels ? Assuredly not those which ran straight athwart all the mental differences between men and women. No amount of female education could ever make equal this natural inequality, nor was it desirable that it should. Woman was the 80 Mr. G. J. Bomanes on Mental Differences, &c. [March 18, natural complement, not the natural rival of man ; and the qualities of mind wherein he excels were not, sui generis, the most exalted of human faculties. Mere strength, whether of mind or of body, was not the highest criterion of nobility ; the truest grandeur of human nature was revealed by that nature as a whole, and here there could be no doubt that the feminine type was fully equal to the masculine. But while we might hope that social opinion might ever continue to oppose the woman's movement in its most extreme forms — or those forms which aimed at setting up an unnatural and therefore impos- sible rivalry in the struggles of practical life — we might also hope that social opinion would soon become unanimous in its encourage- ment of the higher education of women. The lecturer proceeded to enumerate the many advantages to which this would lead, and to dispose of arguments on the other side. [G. J. E.] 1887.] Lord Bayleigh on the Colours of Thin Plates. 81 WEEKLY EVENING MEETING, Friday, March 25, 1887. Sir Frederick Abel, C.B. D.C.L. F.R.S. Manager and Vice-President, in the Chair. The Eight Hon. Lord Rayleigh, M.A. D.C.L. LL.D. F.R.S. M.B.I. On the Colours of Thin Plates. The physical theory, as founded by Young and perfected by his successors, shows how to ascertain the composition of the light reflected from a plate of given material and thickness when the incident light is white ; but it does not, and cannot tell us, except very roughly, what the colour of the light of such composition will be. For this purpose we must call to our aid the theory of compound colours, and such investigations as were made by Maxwell upon the chromatic relations of the spectrum colours themselves. Maxwell found that on Newton's chromatic diagram the curve representative of the spectrum takes approximately ^he simple form of two sides of a triangle, of which the angular points represent a definite red, a definite green, and a definite violet. The statement implies that yellow is a compound colour, a mixture of red and green. In illustration of this fact, an experiment was shown in which a compound yellow was produced by absorbing agents. An infu- sion of litmus absorbs the yellow and orange rays ; a thin layer of bichromate of potash removes the blue. Under the joint operation of these colouring matters the spectrum is reduced to its red and green elements, as may be proved by prismatic analysis ; but, if the pro- portions are suitably chosen, the colour of the mixed light is yellow or orange. When the slit of the usual arrangement is replaced by a moderately large circular aperture, the prism throws upon the screen two circles of red and green light, which partially overlaj). Where the lights are separated, the red and green aj)pear ; where they are combined, the resultant colour is yellow. On the basis of Maxwell's data it is possible to calculate the colours of thin plates and to exhibit the results in the form of a curve upon Newton's diagram. The curve starts at a definite point, corresponding to an infinitely small thickness of the plate. This point is somewhat upon the blue side of white. As the thickness increases the curve passes very close to white, a little upon the green side. It then approaches the side of the triangle, indicating a full orange ; and so on. In this way the colours of the various orders of Newton's scale are exhibited and explained. The principal dis- VoL. XII. (No. 81.) G 82 Lord Bayleigh on the Colours of Thin Plates. [March 25, crepancy between the curve and the descriptions of previous observers relates to the precedence of the reds of the first and second orders. The latter has usually been considered to be the superior, while the diagram supports the claim of the former. The explanation is to be found in the inferior brightness (as distinguished from purity) of the red of the first order and its consequent greater liability to suffer by contamination with white light. Such white light, foreign to the true j)henemenon, is always present when the thin plate is a i)late of air enclosed between glass lenses. To make the comparison fairly, a soaj) film must be used, or recourse may be had to the almost identical series of colours presented by moderately thin plates of doubly refracting crystals when traversed by polarised light. Under these circumstances the red of the first order is seen to be equal or superior to that of the second order. [Kayleigh.] 1887.] Professor Dewar on Light as an Anah/tic Agent. SI WEEKLY EVENING MEETING, Friday, April 1, 1887. Sir Frederick Abel, C.B. D.C.L. F.E.S. Manager and Vice- Presidentj in the Chair. Professor Dewar, M»A. F.R.S. MMJ. Light as an Analytic Agent. Analytical research by means of the agency of light is usually carried out by observing the effects produced on ifght of known quality by transmission through or reflection from matter; or on the other hand, by stimulating matter by the agency of heat or electricity to evolve light, and thereby noting its special qualities In previous lectures I have given an account of the results of a series of experiments, undertaken in concert with my colleague Prof Livemg, with the object of elucidating certain obscure speclroscopic phenomena, and I propose this evening to extend the record of our Not long since Berthelot published the results of some investiga- tions of the rate of propagation of the explosion of mixtures of oxylen with hydrogen and other gases. He found that in a mixture of oxvL^en and hydrogen m the proportions in which they occur in water, the ex- plosion progressed along a tube at the rate of 2841 metres per second • not lar from the velocity of mean square for hydrogen particles on the dynamic theory of gases, at a temperature of 2000°. Ihis IS a velocity which, though very far short of the velocity of light, bears a ratio to it which cannot be called insensible. It is in lact about totVo 0 part of it. Hence if the explosion were advancing towards the eye, the waves of light would proceed from a series of particles lit up m succession at this rate. This would be equivalent to a shortemng of the wave-length of the light by about ^ J — part • and m the case of the yellow fodium lines^ould proklJe^rshfft of the lines towards the more refrangible side of the spectrum by a distance of about -j-i^ of the space between the two lines. It would require an instrument of very high dispersive power and sharply dehned lines to make such a displacement appreciable. With lines of longer wave-length than the yellow sodium lines, the displacement ZrA ' f ^P^^'^^^^.^*^VT ^'""^T- ^^^■*^^"' ^^ ^ receding explosion could be observed simultaneously with an advancing explosion the relative shift of the line would be doubled, one imlge of the line observed being thrown as much towards the less-refrangible side of Its proper position as the other was thrown towardi the more- refrangible side. The two images of the red line of lithium would in G 2 84 Professor Dewar [April 1, this way be separated by a distance of about |^ of a unit of Angstrom's scale ; a quantity quite appreciable, though much less than the distance between the components of tg, and about equal to the distance of the components of the less refrangible of the pair of lines E. We thought therefore that we might test theory by experiment. A preliminary question had, however, to be answered. What lines could be seen in the flash of the exjDloding gases ? We were pretty certain that the hydrogen lines could not be seen, but that probably we might get sufficient dust of sodium compounds floating in the gas to make the sodium lines visible. A preliminary observa- tion was made on the flash of mixed hydrogen and oxygen in a Cavendish's eudiometer, which showed not only the yellow sodium lines, but the orange and green bands of lime and the indigo line of calcium all very brightly, as well as other lines not identified. The flash is very instantaneous, but nevertheless produces a strong im- pression on the eye ; and by admitting the light of a flame into the spectroscope at the same time as that of the flash, the identity of the lines was established. That sodium should make itself seen was not surprising, but that the spectrum of lime should also be so bright had not been anticipated. At first we thought that some spray of the water over which the gases were confined must have found its way into the eudiometer ; but subsequent observations led us rather to suppose that the lime was derived from the glass of the eudiometer. The lime-spectrum made its appearance when the eudiometer was quite clean and dry, and when the gases had been standing over water for a long time. To obtain the high dispersion requisite, as already explained, we made use of one of Eowland's magnificent gratings, with a ruled surface of 3^ by 2i inches, and the lines 14,438 to the inch. One telescope fitted with a collimating eye-piece served both as collimator and observing-telescope ; and by this means we were able to use the spectra of the third and fourth orders with good effect. Observations were made with this instrument on explosions in an iron tube shown in section in Fig. 1, half an inch in diameter, fitted at the end with a thick glass plate (a), held on by a screw-cap (c) and made tight with leaden washers. Small lateral tubes {d, d), at right angles to the main tube, were brazed into it near the two ends, for the jDurpose of connecting it with the air-pump, admitting the gases, and firing them. For this last purpose a platinum wire (h) fused into glass was cemented into the small tube, so that an electric spark could be passed from the wire to the side of the small tube when the gases were to be exploded. To bring out the lithium lines, a small quantity of lithium carbonate in fine powder was blown into the tube before the cap with glass plate was screwed on. Powder was used because wo supposed that it must be loose dust which would be lighted up by the explosion. The lithium lines came out bright enough, and it was unnecessary to put in any more lithium for any number of explosions. The tube 1887.] on Light as an Analytic Agent. 85 was of course quite wet after the first explosion from the water formed but the lithium lines were none the less strong. Indeed after the tube had been very thoroughly washed out, the lithium lines continued to be visible at each explosion, though less brightly than at first A good deal of continuous spectrmn Accompanies th^ !ww- ' iT * u ^^^^"l^^PPi^g of spectra of different orders, makes observations difficult, so a screen of red glass was used to cut this off when the lithium red line was under observation. In any case however, close observation of the flashes is very trying, from the suddenness with which the illumination appears, and thetriefness of Its duration. At first we compared the lithium line given by the flash of the exploding gases with that produced by the flame of a small Bunsen burner m which a bead of fused lithium carbonate was «L. 'i i^^ Tf/'i,*^^^^^^ ^* ^^"^- ^^il^ t^e flame-line was sharply defined the flash-lme had a different character, and was always diffuse at the edges; so that it was not possible in this way to sub- stantiate the minute difference of wave-length indicated by theory, of thf two^ fl^sh-lme certainly seemed a little the more refrangible We then tried taking the explosion in a tube bent round so as to pnTnT Tfi '^'f' *^%*''^ P^"*^ ^^ *^^ *"^^ being parallel to each other, and the glass ends side by side (Fig. 2). The axis of the so W r/fl^ 1 T\^^'' f °'^'^^' ""'^^ *^^* ^^ ^^^ ^^^b of the tube, so that the flash m that limb was seen directly ; and by means of two reflecting prisms (r,r) the light from the other limb was thrown into tne slit, and the two images were seen simultaneously one above the otlier. As the gas was ignited from one end of the tube, the flash was seen receding m one limb, approaching in the other, so that the displacement of the two lines would be doubled. Still we were unable to substantiate any relative displacement of the lines on account of their breadth and diffuse character. By washing out the tube the bi-eadth of the lines was considerably reduced, but thev remained diftuse at the edges, and baffled any observation sufficiently accurate to establish a displacement. Certainly there appeared to be 86 Professor Dewar [April 1, a very slight displacement, but it was not so definite that one could be sure of it. These observations, however, led us to some other interesting results. In the first place, one of the two images of the lithium line almost always was reversed — that is, showed a dark line down the middle. This was the line given by the flash approaching the slit. The receding flash in the other limb of the tube gave as broad a bright line, but it had no dark line in its middle. This observation was made a great many times ; and the fact of the reversal established independently in the case of some other metallic lines by means of l^hotographs. These reversals show that in the wave of explosion the temperature of the gases does not reach its maximum all at once; but the front of the wave is cooler than the part which follows and absorbs some of its radiation, while the rear of the wave does not produce the same effect. One would suppose that there must be cooler lithium-vapour in the rear of the wave as well as in its front ; but it is possible that the absorption produced by it extends over the whole width of the line, and not only over a narrow strip in the middle. For we observed that when a little lithium carbonate was freshly put into the tube, the red line was so much expanded as to fill the whole field of view — that is to say, it was some ten or twelve times as wide as the distance between the two yellow lines of sodium ; but by washing out the tube with water (that is, by reducing the quantity of lithium present in the tube), the line could be reduced in width until it was no wider than one-tenth of the distance between the two sodium lines. This seeins to prove that the breadth of the line is directly dependent on the amount of lithium present. M. Fievez has, in a recent publication (' Bulletins de I'Academie roynle de Belgique'), concluded, from observations on sodium, that the widening of the lines is solely due to elevation of temperature. The flash of the exploding gases cannot be raised in temperature by the presence of a minute quantity more of a lithium compound ; so that in our case the widening cannot be ascribed to anything but the increase in the quantity of lithium present, or to some consequence of that increase. It is not improbable that the amount of lithium vaporised in the front of the wave of explosion is less than in the following part, and hence the absorption-line is not so wide as tho bright line behind it, while in the rear of the wave the absorption extends over the whole width of the bright band, and so is not so easily noticed. Only twice amongst many observations was any reversal of the lithium line seen in the receding wave of explosion. On observing the flash with a spectroscope of small dispersion instead of that with the grating, the continuous spectrum was very bright, but the metallic lines stood out still brighter ; not only the red line of lithium, but the orange, the green, and the blue lines were very bright, and continued so when the pressure of the gases before explosion was reduced from one atmosphere to one-third of an at^ mosphere, The violet line was not seen, but it may have been so 1887.] on Light as an Analytic Agent. 87 much expanded as to be lost in the continuous spectrum ; for it showed in a photograph afterwards taken. Other lines were, how- ever, seen — the sodium yellow lines, the calcium indigo line, a group of other blue lines, and a group of green lines, amongst which one line was conspicuous, and this line, by comparison with the solar spectrum, was identified with E. We had not expected to see any lines of iron, as iron and its compounds give no lines in the flame of a Bunsen burner, and we supposed that it would only be volatilised at a much higher temperature. But the appearance of E suggested that other of the green and blue lines might be due to iron ; so we proceeded to compare the positions of these lines with those of the electric spark between iron electrodes. For this purpose one of the spark-lines was first brought carefully on to the pointer, or cross wires, in the eye-piece of the observing telescope, and then, the passage of the spark being stopped, the flash of the exploding gases was observed. It was not difficult to see whether any line was on the pointer ; and the observation could be repeated as many times as was desired without any shift of the apparatus. Nine of the most conspicuous green and yellowish-green lines in the flash were thus identified with lines of iron. For the blue and violet we adopted the photographic method as much less trying to the eyesight. Eight to twelve flashes were taken in succession without any shift of the apparatus, so as to accumulate their effects on the photographic plate. Eight flashes were found enough in 'general to produce a good im- pression, and more than twelve could not well be taken without turning out the water which accumulated in the tube, and cleaning the glass which closed its end. After the flashes had been taken, but without shifting the photographic plate, the slit of the spectro- scope was partly covered, and the electric spark between iron points passed in front of the slit. We had thus on the plate the photograph of the flash as well as of the sj)ark. Fourteen more lines in the in- digo and violet were thus identified with iron lines ; and on extending the photographs into the ultra-violet, and substituting quartz lenses and prisms for the glass ones hitherto used, a much larger number of lines were identified. There could be no doubt, then, that we had iron vapour in the flash. We supposed that it must be derived from dust of oxide shaken by the explosion off the sides of the tube, and we had the tube bored out clean and bright like a gun-barrel. This made no diminution in the brightness or number of the lines ; and we came to the conclusion that the explosion detached particles of iron from the tube, and converted them into vapour. This was confirmed by finding that, however carefully the tube had been cleaned, the glass ends always became clouded with a rusty deposit after ten or twelve flashes. Altogether 68 lines of iron have been identified in the flash, of which about 40 lie in the ultra-violet between H and 0. Only one iron line above O has been definitely identified, and that in only a few photographs. It is T. As iron gave so many lines in the flash it was reasonable to sup- 88 Professor Deivar [April 1, pose that more volatile metals would give their lines too. Linings of thin sheet copj^er, lead, cadmium, zinc, aluminium, and tin were successively j)ut into the tube, and their effects on the flash observed. Copper gave one strong line in the green (wave-length 5104: "9), but no other line in the visible part of the sjDectrum. In the ultra-violet two strong lines between Q and R came out in the photographs, fre- quently as reversed lines. Some of the photographs showed also something of the shaded bands in the blue which are ascribed to the oxide of copper. The green line of copj^er had been observed in the flash before the cojDper lining was put into the tube ; and we con- cluded that the cojDjjer was derived from the brass with which the small lateral tubes were fastened into the large tube, or that the iron of the tube contained a little copper. When the leaden lining was used, only one visible line of lead was developed, and that was the strong violet line, but two ultra-violet lines between M and N were strongly depicted on the photographic plates. The violet line of lead had also been observed in many of the photograjDhs taken before the leaden lining was introduced. This we ascribed to the leaden washers used to make the glass or quartz plates air-tight. The line was greatly increased in strength by the leaden lining. The zinc lining gave no visible line at all, notwithstanding the easy volatility of the metal ; and in the ultra-violet it gave only a very doubtful impression of one of the lines near P. The cadmium, aluminium, and tin linings gave no lines at all. Zinc dust put into the tube gave no zinc lines, merely increased the continuous spectrum, and speedily rendered the quartz end opaque. A clean wire of magnesium put into the tube gave the h group of lines, but no other line. No trace of the blue lino, so conspicuous in the flame of burning magnesium, nor of the triplets near L and S, nor of the very strong line, the strongest of all in the arc, at wave- length 2852. b^ and bn were well seen ; but as b^ is an iron line, as well as a magnesium line, and the iron line was visible in the flash before the magnesium wire was introduced, we cannot be sure whether the magnesium line, as well as the iron line, was present in the flash. Magnesia did not develop any line at all; merely augmented the continuous spectrum. Compounds of sodium, such as the carbonate and chloride, intro- duced in powder gave the ultra-violet line between P and Q strongly, frequently reversed ; but no other line except of course D. Potassium compounds developed, often reversed, the pair of violet lines, and also the ultra-violet pair near O, but no others. A strip of silver developed two ultra-violet lines, one on either side of P ; but we could not detect in the flash the well-known green lines of that metal. When powder of silver oxalate was introduced, the yellowish- green line (w.l. 5464:) was seen at the first explosion but not afterwards. As silver oxalate is itself an explosive compound, decomposing with an evolution of heat, it is reasonable to ascribe the appearance of this line at the first explosion to the extra temperature so engendered. 1887.] on Light as an Analytic Agent. 89 Strips of copper, electroplated with nickel, brought out almost all the strong nickel lines in the ultra-violet between K and Q ; 25 were photographed. When nickel oxalate was put in so as to give a powder of metallic nickel after the first explosion, the same lines were developed, and three additional lines in the ultra-violet. Only one line was seen in the visible part of the sj)ectrum, and that was the yellowish-green line (w.l. 5476). Coj)per wires electroplated with cobalt gave in the flash 22 lines in the violet and ultra-violet, between G and P ; no lines beyond those limits. Cobalt oxalate gave no more. No other metal gave anything like so many lines as iron, nickel, and cobalt ; and it is remarkable that almost all the lines of these metals develoj)ed in the flash lie in the same region between G and P. We exj)ected that manganese would have given several lines in the flash ; but it was not so. Neither metallic manganese, nor any of several compounds which we tried, gave us any lines of that metal except the violet triplet, and this was generally given by the iron tube alone, and was merely stronger for the manganese put in. The green channellings characteristic of manganese, and ascribed to the oxide, were, however, well seen when metallic manganese was used. Chromium, introduced as bichromate of ammonia, which of course became chromium oxide at the first flash, gave three triplets in the green, the indigo, and the ultra-violet near N respectively, but no other lines. , Bismuth, antimony, and arsenic gave no lines, nor did mercury spread over a sheet of copper lining the tube. Several metals were tried as amalgams spread over such a piece of copper, but with no fresh results, except in the case of thallium, which gave the green line strongly, the strong line between L and M, and two lines between N and O. On the whole it does not appear that the form in w^hich the metal is introduced into the tube makes much difference. The merest traces of those which gave lines were sufficient. Generally when a metal had been put into the tube, its lines continued to show after the strip or lining had been removed. Thus, after the nickel strips had been taken out, and the tube cleaned out as completely as it could be mechanically, the nickel lines still came out in the flash, and the same was the case with other metals. The strongest part of the water-sjDcctrum, from s to near R, generally impressed itself more or less on the photograj)hic plate ; but, with the exception of T, which was only developed once or twice, no lines made their appearance in the region more refrangible than s. Thus far the experiments had been made with the gases at the atmosj)heric pressure, or nearly so, before ignition. The proportions of hydrogen and oxygen were nearly two to one ; but an excess of either gas to the extent of one-fifth did not sensibly affect the results. Other explosive mixtures were tried. Carbonic oxide with 90 Professor Dewar [April 1, oxygen, and marsh-gas with oxygen, developed in general the same lines as the hydrogen mixture, but gave a much brighter continuous spectrum. Sulphuretted hydrogen, arseniuretted hydrogen, and antimoniuretted hydrogen, exploded with oxygen, also gave very bright continuous spectra, but no lines attributable to sulphur, arsenic, or antimony. We have also tried explosions at higher pressures ; mixtures of hydi'ogen, carbonic oxide, and marsh-gas respectively, with oxygen, were compressed into the tube by a condensing syringe until the pressure reached two and a half atmospheres, and in some cases three and a half atmospheres. The general effect of increasing the pressure was to strengthen very much the continuous spectrum, and also to intensify the bright lines, so that photographs could be taken with a smaller number of explosions. The lines previously observed to be reversed were more strongly reversed, but no new lines which we can attribute to the metals employed were noticed. No iron line more refrangible than T showed itself in the photographs. But a banded spectrum, of which traces had been noticed in the flash of the gases at lower pressure, came out decidedly. This spectrum occupies the region between P and E ; it is not a regularly channelled spectrum, though probably under higher dispersion it would resolve itself into groups of lines like the water-spectrum. In fact it seems to us most probable that it is a development of the water spectrum, dependent on the pressure. It seems very remarkable that metals so little volatile as iron, nickel, and cobalt should develop so many lines* in the flash, while more volatile metals show few or no lines. We do not know that any lines attributed to the metals, as distinct from their compounds, which have been observed in the gas-flame cannot be seen also in the flash of the exploding gases, unless they be the blue lines of zinc which Lecoq de Boisbaudran has seen faintly in the gas-flame when zinc chloride was introduced. These are, however, so faint in the flame, that they might easily escape notice in the much stronger continuous spectrum of the flash. But iron, nickel, and cobalt show no lines of those metals in a gas-flame. Mitscherlich (' Ann. de Phys. u. Chem.' Bd. 121, St. 3), by mixing vapour of ferric chloride with the hydrogen burnt in an oxyhydrogen-jet, obtained a number of the lines of iron. These form three groups — one below D, one near E, and one near G. The last two groups have a general correspondence with the lines developed in the explosions in the visible part of the spectrum ; but exact identification is not possible with his figure. Of other metals he seems also to have found the same lines in the oxyhydrogen-jet which we have seen in the explosions, but with additional lines in several cases. Thus he found three zinc and as many cadmium lines, two of mercury, four of copper, and so on. Gouy (' Comptes Rendus,' Ixxxiv. 1877, p. 232) has observed in * For detailed list of these lines see « Proc. Koy. Soc' vol. xxxvi. pp. 473-5. 1887.] on Light as mi Analytic Agent. 91 the inner green cone of a modified Bunsen burner fed with gas mixed with spray of iron-salts, four green lines of iron which we did not fi.nd in the flash. He saw two of the blue lines, but not the other lines which we have noticed. In like manner with cobalt, he observed two feeble blue rays which we did not see in the exj)losions ; also one zinc, one cadmium, and one silver line which we did not see ; and he did not notice the green copper line which we always have seen in the explosions. In other cases he has noticed the same lines that we have noticed. Comparing the spectrum of the explosions with that of iron wire burnt in a jet of coal-gas fed with oxygen, they may be called identical. We find in them generally the same lines and the same relative strengths of the lines. For instance, in the explosion- spectrum the strength of the groups of lines on either side of M and the line at wave-length 3859*2 is decidedly greater as compared with the other lines than it is in the arc-spectrum of iron. It is the same in that of iron burnt as above mentioned. T, however, comes out more strongly in the last-mentioned spectrum than in the ex- plosions. German-silver wire burnt in the coal'gas and oxygen jet gave the same nickel and copper lines as were developed in the explosions. Silver wire gave in the same jet the two silver lines near P, but no channelled spectrum. SjDray of cobalt chloride gave also the same lines as in the explosions, with a few additional; while spray of manganese chloride gave the strong manganese triplet at wave-length about 2800, more refrangible than anything observed in the explo- sions, besides the usual violet triplet. On the whole the spectra produced by the jet of coal-gas and oxygen are very similar to those of the explosions as far as the metallic lines go ; they exhibit a few more lines, or it may be these are more easily observed. Of the green and blue lines of iron seen by us in explosions nine are registered by Watts as occurring in the flame of a Bessemer con- verter ; or at least the lines he gives are so near that we cannot doubt their identity. When we come to make a comparison with the spectrum of the spark-discharge from a solution of ferric chloride, the differences become more marked. Not only are there many more lines in the spark-spectrum, but the relative intensities of those lines which are common to both spark and explosion are very different, and two of the iron lines seen in the explosions appear to be absent from the spark. The differences between the spectrum of the spark taken from a liquid electrode and that given by solid electrodes has usually been attributed to the lower temperature of the former ; but the absence from the former spectrum of the line at wave-length 4132, and the feebleness of the line at wave-length 4143, both strong lines in the arc and in the explosions, as well as in the spark between solid electrodes, seem to indicate that the differences of spark-spectra 92 Professor Deivar [April 1, are not simply due to differences of temperature. In fact we know so little about the mechanism, so to speak, of the changes of electric energy into heat, and of heat into radiation, that there is no good reason for assuming that the energy which takes the form of radiation in the electric discharge through a gas must first take the form of the motion of translation of the particles on which temperature depends. The gas may, for a short time, be intensely luminous at a very low temperature ; and if the impulses which give rise to the vibratory movements of the particles be of different characters, the characters of the vibrations also may differ within certain limits. Leaving, however, the realms of speculation, we may mention that we have before observed the spectrum of iron at a temperature intermediate between that of the oxyhydrogen-jet and that of the electric arc. Some time since (' Proc. E. S.' xxxiv. p. 119, and ' Proc. Camb. Phil. Soc' iv. p. 256) we described the spectrum proceeding from the interior of a carbon tube strongly heated by the electric arc playing on the outside. This spectrum approaches more nearly to that of the arc inasmuch as it shows all, or almost all, the iron lines given by the arc betw^een F and 0, and the aluminium pair between H and K ; but it resembles the explosion-spectrum in the relative strength of some of the iron lines, and in the absence of almost all iron lines between 0 and T. The iron lines seen reversed against the hot walls of the carbon-tube correspond with the strongest of the explosion- lines ; the strong lines near M and a little below L in the explosions being those most strongly reversed in the photographs of the carbon- tube. The greater comjilctencss and extent of the iron spectrum, as well as the presence of the aluminium lines, which are entirely wanting in the explosion-spectrum, indicate that the temperature of the tube was higher than that of the explosion. That iron, nickel, and cobalt are volatile in some degree at the temperature of the explosion appears to be proved, and makes the api)earance of iron lines at the very apices of solar prominences, as observed by Young, less astounding than it seemed to be at first sight. The ascending current of gas making the prominence may very well carry iron vapour with it ; or we may not unreasonably suppose that there is meteoric dust containing iron everywhere in the outer atmosphere of the sun, which becomes volatilised, and emits the radiation observed, when it is heated up by the hot current of the prominence. What the temperature of such a current may be we cannot well gauge, but it is high enough to give the hydrogen-spectrum, of which no trace has been observed in the flash of the exi^losions or in the oxy-hydrogen- jet. The temperature of the explosions we know with tolerable accuracy, at least when the gases are at atmospheric pressure to begin with. Bunsen (' Phil. Mag.' 1867, p. 494) found the pressure of the explosion W' as for hydrogen and oxygen 9 • 6 atmosj)heres, and for carbonic oxide and oxygen 10*3 atmospheres, and he calculated the corresponding temperatures to be 2844° and 3033°. 1887.] on Light as an Analytic Agent. 93 Eecently published observations by Bertbelot and Vieille (' Comptes Eendus,' xcviii. 1884, p. 548) put the pressure of explosion of oxygen and hydrogen at 9 • 8 atmospheres, and of carbonic oxide and oxygen at 10*1, and the corresponding temperatures 3240^ and 3334°. The pressures determined by the two observers agree closely, and the calculated temperatures are not very discordant. On the whole, we cannot be wrong in assuming the temperature of the exploding gases to be about 3000° ; and we see that at this degree such metals as iron, nickel, and cobalt are vaporous, and emit many characteristic rays, and that by far the greatest part of these rays lie between narrow limits of refrangibility, G and P. Even for other metals there is a predominance of rays in the same part of the spectrum. The lines of lead, potassium, and manganese, three out of four lines of thallium, and two-thirds of those of chromium, observed in the explosions, fall within the same region. It must not be inferred that these facts indicate the limit of the rate of oscillation which can be set up in consequence of an elevation of temperature to 3000^, because we know that the spectrum of the lime-light extends much further. But it might be possible to establish a sort of spectroscopic scale of tempera- tures if the lines which are successively developed as the temperature rises were carefully noted. Thus the appearance of the iron line T seems to synchronise with temperature of about 3000°. The lithium blue line is invisible in the flame of an ordinary Bunsen burner, but is just visible at the temperature of the inner green cone formed by reducing the proportion of gas to air in such a burner, while in the exploding gas the green line too is seen. It seems to need a tempera- ture above 3000° to get the aluminium lines at H. Probably no line is ever abruptly brought out at a particular temperature — it will always be gradually developed as the temperature rises; yet the development may be rapid enough to give an indication which may be useful in default of means of more exact measurement. In former papers treating of spectroscopic problems (' Proc. Eoy. Soc' vol. xxxiv. p. 130, and xxix. p. 489) we have more than once adverted to the necessity of the study of the spectra both of flames and of the electric discharge under modified conditions of pressure. The projected ex- periments on the arc in lime-crucibles have not yet been carried out ; but the present is a first instalment of a study of flame-spectra under such conditions. [J. D.] 94 General Monthly Meeting. [April 4, GENERAL MONTHLY MEETING, Monday, April 4, 1887. His Grace The Duke of Northumberland, E.G. D.C.L. LL.D. President, in tlie Chair. The Managers reported, That at their Meeting on the 7th of March last the following letter from Dr. Tyndall to the Honorary Secretary was read : — Hind Head, Haslemeke. My dear Sir Frederick Bramwell, '^'^'■^''' ^'''' ^^^''^ The yeai''s holiday so graciously and considerately granted me by the Managers will come to an end next month ; and it therefore behoves me to state without further delay, for the information of the Managers, how matters stand with me. A brief conversation with my friend Sir Frederick Pollock, and my own re- flections thereupon, have convinced me that, instead of making a statement myself at the Board Meeting on Monday, it will be more expedient to embody what I have to say in a letter to you. For more than one-third of a century it has been my privilege to enjoy the unfailing sympathy and encouragement of the Managers and Members of the Royal Institution. It is now my duty to return to their hands the trust which they first committed to me in the spring of 1853. I have come to this resolution on account of the need I feel of thorough rest, and of freedom from engagements, as to lecturing, the non-fulfilment of which W'Ould be detrimental to the Institu- tion, and a cause of sore distress to myself. Worries connected with building, and other worries inimical to quietude of brain, have for the last few years troubled me much. These are now, for the most part, tilings of the past, so that the freedom I seek will, I doubt not, soon restore me to good health. I returned from Switzerland in October so refreshed and invigorated that I hoped to be able to cope successfully with all the duties then before me. I had assured myself of the friendly aid of Mr. Crookes, and had even arranged to go to Paris to purchase some instruments necessary for my contemplated work. To the end of the year my health continued strong. Then came a long-continued spell of withering easterly winds, which chilled me, dried me up, and brought on an attack of sleeplessness, intense while it lasted, but which, happily, has iu great part disappeared with its cause. Of my ultimate and complete recovery I entertain little doubt. Still it would be obviously unfair to the Members, as it would be intolerable to myself, to allow the fortunes of our great Institution to depend in any degree upon such caprices of health. It is therefore my desire to make room for a successor whose years and vigour will place him beyond all changes and chances of this kind. Of the feelings called forth by my separation from the Royal Institution I have said nothing. But the Managers will understand that my silence in this res- pect is due, not to the absence of such feelings, but only to the conviction that on the present occasion the less said about them the better. Believe me, Most faithfully yours, John Tyndall. 1887.] General Monthly Meeting. 95 The Managers further reported, That at their adjourned Meeting on the 21st of March the following Resolutions were adopted : — Resolved, "That the Managers desh-e to record by this Eesolution the expression of their deep regret that the state of Dr. Tyndall's health sliould have rendered necessary the resignation of his position of Professor of Natural Philosophy at the Koyal Institution, and that it should have compelled the Managers to accept that resignation — and desire at the same time to record the expression of their hope that the relief thus obtained from the arduous duties of the Professorship will conduce to his speedy and complete recovery. " The Managers also desire that there should be recorded the expression of their thorough appreciation of the unremitting and most valuable services which during the long period of thirty-four years Dr. Tyndall has rendered to the Royal Institution in carrying out the duties of his office — services which not only have upheld and have advanced the position of the Royal Institution, but have benefited science and the world at large." " The Managers having ascertained without doubt that Professor Tyndall altogether declines to receive any pension or pecuniary testimonial in recognition of his services to the Royal Institution, and that in parting from his long con- nection with it he desires only to carry with him the friendly recollection and goodwill of the Members," Resolved, " That this generous and disinterested refusal to accept any acknow- ledgment of a pecuniary nature upon the occasion of his retirement cannot fail to increase the feelings of regard and respect which must be entertained for Professor Tyndall's devotion of so much of his life to the important researches which have been prosecuted by him in the laboratories of the Institution, and for the delivery of those eloquent lectures in its theatre which has done so much to support its scientific renown and to increase its prosperity. The Managers, therefore, under the before-mentioned circumstances of Dr. Tyndall's refusal to accept any pension or pecuniary testimonial, resolved that some marked recogni- tion of a permanent character should be given to the opinion entertained of the great value of Professor Tyndall's labours now about to cease, and the Managers trust that it may prove as agreeable to him as it will be honourable to the Institu- tion, if he would kindly comply with a request which they recommend should be made to him, to sit for his bust (in marble), to be placed in the house of the Institution in perpetual memory of his relations with it, and the cost of which should be defrayed by a vote from the general funds of the Institution, and in order further to perpetuate and honour the name of Professor Tyndall in con- nection with the Institution, the Managers recommend that one of the courses of Lectures delivered annually in the Institution shall be called the Tyndall Lectures." Resolved, " That the Honorary Secretary, in informing Dr. Tyndall of the acceptance of his resignation, do send to him a copy of the foregoing Resolutions." The Managers further reported, That at their Meeting held this day the following letter was read : Deae Sir FredeEICK BeAMWELL, Hind Head, 3rd April, 1887. I have halted in my reply to your letter of March 23rd, through eheer inability to express the feeling which the action of the Managers, at their meeting on the 21st, has called into life. And my reply must now be brief; for I hardly dare trust myself to dwell upon the " Resolutions " which you have conveyed to me. Taken in connexion with the severance of my life from the Royal institution, and with the flood of memories liberated by the occasion, this plenteous kindness, this bounty of friendship, this reward so much in excess of my merits, well-nigh unmans me. And, let me add, the noble fullness of style and expression, which I owe to 96 General Monthly Meeting. [April 4, yourself, and in which the goodwill of the Managers takes corporate form, is in perfect harmony with the spirit which it enshrines. Of the Managers existent when I joined the Institution, one only remains upon the present Board. The beneficent work of many of them is for ever ended ; but I do not forget the sympathy and support which they extended to me during their lives. And now the long line of kindnesses culminates in words and deeds so considerate and appreciative— so representative of their origin in true gentlemanhood, and warmth of heart, that they have almost succeeded in converting into happiness the sadness of my farewell. With heartfelt prayers for the long-continued honour and prosperity of the Institution which I have served so long, and loved so well, Believe me, dear Sir Frederick, Most faithfully yours, John Ttndall. The Managers further reported, That it was Resolved, "That having regard to the distinguished services rendered to the Eoyal Institution by Dr. Tyndall, he be recommended to the Members for election as Honorary Professor of Natural Philosophy." It was then moved, and Resolved, unanimously, " That Dr. Tyndall be nominated for election at the next General Monthly Meeting on Monday, May 9th, as Honorary Professor of Natural Philosophy." Arthur Gamgee, M.D. F.R.S. Edward Bagnall Poulton, Esq. M.A. F.G.S. F.Z.S. Miss Frances Harriet Whitehead, were elected Members of the Eoyal Institution. The Right Hon. Lord Rayleigh, M.A. D.C.L. F.R.S. 3I.B.L was nominated for election as Professor of Natural Philosophy at the next General Monthly Meeting on May 9. The following Arrangements for the Lectures after Easter were announced : — John Hopkinson, Esq. M.A. D.Sc. F.R.S. B.S. M. Inst.C.E. 3I.B.L— Four Lectures on Electricity ; on Tuesdays, April 19, 26, May 3, 10. Victor Horsley, Esq. F.R.S. B.S. F.R.C.S.— Three Lectures on The Modern Physiology of the Brain and its Relation to the Mind ; on Tuesdays, May 17, 24, 31. The Rev. J. P. Mahafey, D.D. Professor of Ancient History in the University of Dublin. — Three Lectures on The Hellenism of Alexander's Empire : Lecture I. on Tuesday, June 7, Macedonia and Greece ; Lecture II. on Thursday, June 9, Egypt; Lecture III. on Saturday, June 11, Syria. Professor Dewar, M.A. F.R.S. M.R.L Fullerian Professor of Chemistry, R.I. — Seven Lectures on The Chemistry of the Organic World ; on Thursdays, April 21, 28, May 5, 12, 19, 26, June 2. R. VON Lendenfeld, Esq. Ph.D. — Three Lectures on Recent Scientific Researches in Australasia ; on Saturdays, April, 23, 30, May 7. John W. Hales, Esq. M.A. — Four Lectures on Victorian Literature ; on Saturdays, May 14, 21, 28, June 4. 1887.] General Monthly Meeting. 97 The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FKOM The Governor-General of India — Catalogue of Siwalik Vertebrata. By R. Lydekker. 2 parts. 8vo. 1885-6. Catalogue of Pleistocene and Prehistoric Vertebrata. By R. Lydekker. Svo. 1886. Geological Survey of India. Recor.ls, Vol. XX. Part 1. 8vo. 1887. Memoirs : Pala3ontologia Indica. Ser. XII. Vol. IV. Part 2 ; Ser. XIII. Part 1, Fasc. 6. 4to. 1886. The New Zealand Government— Staiiaiics of the Colony of New Zealand, 1885. fol. 1886. The Secretary of State fur India — Report on Public Instruction in Bengal, 1885-6. fol. 1886. Accademia dei Lincei, Beale, Roma — Atti, Serie Quarta ; Rendiconti. Vol. III. 1-^ Semestre, Fasc. 3. 8vo. 1887. American Philusophical Society — Proceedings, No. 124. 8vo. 1886. Astronomical Society, Royal — Monthly Notices, Vol. XLVII. No. 4. Svo. 1887. Ateneo Fewefo— Re vista Mensile, Oct. 1885 to Oct, 1886. Svo. Bankers, Institute o/— Journal, Vol. VIII. Part 3. Svo. 1887. British Architects, Royal Institute o/— Proceedings, 1886-7, Nos. 11, 12. 4to. British Museum, T/ie— Catalogue of Ancient MSS. Part 2, Latin, fol. 1884. Introduction to a Catalogue of the Early Italian Prints. By Richard Fisher. Svo. 1886. Descriptive and Historical Catalogue of Japanese and Chinese Paintings. By W. Anderson. Svo. 1886. Catalogue of Bengali Printed Books. By J. F. Blunihardt. 4to. 1886. Subject Index of Modern Works added to the Library in 1880-5. By G. K. Fortescue. Svo. 1886. Catalogue of Books in the Galleries in they Reading Room. Svo. 1886. Medallic Illustrations of the History of Great Britain and Ireland. By E, Hawkins. Edited by A. W. Franks and H. A. Grueber. 2 vol. Svo. 1885. Catalogue of Indian Coins. 1. Muhammadan States. 2. Sultans of Dehli. 8. Greek and Scythic Kings. Svo. 1885-6. Catalogue of Greek Coins. Crete and ^Egean Islands. Svo. 1886. Cambridge Philosophical Society — Proceedings, Vol. VI. Part 1. Svo. 1887. < Transactions, Vol. XIV. Part 2. 4to. 1887. Chemical Society — Journal for March 1887. Svo. Daicson, George M. Esq. D.Sc. {the Author) — Certain Borings in Manitoba. (Trans. Roy. Soc. of Canada.) 4to. 1887. Daz: Societe de Borda — Bulletins, 2« Serie, Douzieme Anne'e, 1« Trimestre. Svo. 1887. East India Association — Journal, Vol. XIX. No. 2. Svo. 1887. Editors — American Journal of Science for March 1887. Svo. Analyst for March 1887. Svo. Athenjeum for March 1887. 4to. Chemical News for March 1887. 4to. Chemist and Druggist for March 1887. Svo. Engineer for March 1887. fol. Engineering for March 1887. fol. Horological Journal for March 1887. Svo. Industries for March 1887. fol. Iron for March 1887. 4to. Murray's Magazine for March 1887. Svo. Nature for March 1887. 4to. Revue Scientifique for March 1887. 4to. Scientific News for March 1887. 4to. Telegraphic Journal for March 1887. Svo. Zoophilist for March 1887. 4to. Vol. XII. (No. 81.) h 98 General Monthly Meeting. [April 4, Florence, BiUioteca Nazionale CentraU—BoWeiino, Num. 27, 28, 29. 8vo. ]887. Catalogo dei Codici Palatini. Vol. I. Fasc. 1-5. 8vo. 1885-7. Catalogo dei Codici Panciaticbiani. Vol. I. Fasc. 1. 8vo. 1887. Gioinali Politici. 8vo. 1885-6. Franklin Institute— Jonrnfil, No. 735. 8vo. 1887. Freshfield, Edwin, Esq. LL.D. V.P.S.A. M.B.I. {the ^wf/ior)— Discourse on Some Unpublished Kecords of the City of London. [Delivered at the Royal Insti- tution.] 4to. 1887. Geological Institute, Imperial, Vienna — Abhandlungen, Band XII. Nos. 1, 2, 3. fol. 1886. Jahrbuch, Band XXXVI. Heft 2, 3. 8vo. 1886. Verbandlungen, Nos. 6-12. 8vo. 1886. Georgofili Reale Accademia — Atti, Quarta Serie. Vol. IX. Disp. 4. 8vo. 1886. Hadden, Bev. B. H. — Account of the Old Registers of St. Botolph, Bisliopsgate. By Rev. A. W. C. Hallen. 12mo. 1886. Harlem, Societe Hollandaise des Sciences — Archives Neerlandaises, Tome XXI. Liv. 2, 3. 8vo. 1886-7. Iron and Steel Institute — Journal, 1886, No. 2. 8vo. Japan, Imperial University of — Memoirs of the Literature College, No. 1. 8vo. 1887. Johns Hopkins University— Amencsm Journal of Philology, No. 28. 8vo. 1886. Liverpool Literary and Scientific Society — Proceedings, Vols. XXXIX. XL. 8vo. 1884-6. Manchester Geological Society — Transactions, Vol. XIX. Part 5. 8vo. 1887. Meteorological (>^ce— Quarterly Weather Report, 1878, Part 2. 4to. 1887. Monthly Weather Report for September 1886. 4to. 1887. Weekly Weather Report, Vul. III. No. 53 ; Vol. IV. Nos. 1-6. 4to. 1886-7. Report of Meteorological Council, R.S. to 31st March, 1886. 8vo. 1887. Report of the International Meteorological Committee. 3rd Meeting (1885). 8vo. 1887. Meteorological Society, Boyal — Quarterly Journal, No. 61. Svo. 1887. Meteorological Record, No. 23. 8vo. 1887. Middlesex Hospital—BeportB for 1885. 8vo. 1887. Odontological Society of Great Britain — Transactions, Vol. XIX. Nos. 4, 5. New Series. 8vo. 1887. Pharmaceutical Society of Great Britain — Journal, March 1887. Svo. Photographic Society — Journal, New Series, Vol. XI. Nos. 5, 6. 8vo. 1887. Preussische Ahademie der Wissenschaften — Sitzungsberichte XL.-LIII. Svo. 1886. Boyal Society of London— Proceedinga, Nos. 251, 252. Svo. 1887. Sarideman, David, Esq. (the Author) — Progress of Technical Education, with special reference to the Glasgow Weaving College. Svo. 1886. Saxon Society of Sciences, Boyal — Mathematisch-physische Classe: Beriohte, 1886. Sup. Svo. Society of Arts — Journal, March 1887. Svo. Telegraph Engineers, Society o/— Journal, No. 64. Svo. 1887. United States Geological Survey— huWetins, Nos. 30-33. Svo. 1886. Vereins zur Befdrderung des Geicerbfieisses in Preussen — Verbandlungen, 1887 : Heft 2. 4to. Wild. Dr. H. (D/redor)— Repertorium fur Meteorologie, Sup. 2, 3, 4. 4to. 1SS7. Yorkshire Archseological and Topographical Association — Journal, Part XXXVII. Svo. 1887. Area in Population. Sq. Miles. ''"■' I'r^wT'^" ^''"''"^' ''''''' '"*'^^' 121,500 36,000.000 German^Ocean (Heligoland), ^ ■_ ■ ^ ,,^ ofiffi Mediterranean (Gibraltar, Malta, Cyprus), 4,118 364,000 West Africa (Gambia, Sierra Leone, Gold «7A nnn Coast, Lagos), . • • , • 15.561 6.0,000 Atlantic Ocean (Ascension, bt. Helena, _ Falkland Isles) J''^°l , ~A'7^ South Africa (Cape, Natal, Basutoland), . 2(3,000 l,.4b,000 Indian Ocean (Aden, Perim Mauritius, Borneo, Straits Settlements), . . 2, ,810 1.021,150 India Ceylon, Bunnah, China (Hong Kong), 1,477,407 260,160,000 Australasia (Australia, Tasmania, New Zealand, New Guinea), . . • 3,272,000 3,309,000 South Pacific Ocean (Fiji, Rotumah), . 8.014 , , ''^ North America (Canada, Newfoundland), . 3,540,000 5,loO,000 West Indies, Bermuda*, Trinidad, Hon- 1486 000 duras, Guiana, etc., . • ■ 10t>,035 1,486,000 , „ ■ ; - ^^ Irtstan dg Cunha MApi M*»'„. BRIT'IS Showing the objects ai Impe UNITED KINGDC And the Area and Popi THE QUE 1887.] Sir Frederick Abel on the Work of the Imperial Institute. 99 WEEKLY EVENING MEETING, Friday, April 22, 1887. H.R.H. The Prince of Wales, E.G. F.R.S. Vice-Patron, in tlie Chair. Sir Frederick Abel, C.B. D.C.L. F.R.S. M.B.L The Work of the Imperial Institute. The Colonial and Indian Exhibition, which owes not only its con- ception, but also its brilliantly successful realisation to your Royal Highness, will be pre-eminently remarkable in times to come, for having achieved many results of vital importance and highest benefit to Her Majesty's subjects in all parts of Her vast Realms. The collection of all that is commercially valuable and scientifi- cally interesting of the natural products of the great Indian Empire and of the Colonies in one exhibition, embracing as it also did very comprehensive illustrations of the development of commerce, of the arts and of certain industries, in the many countries beyond the seas which combine with the United Kingdom to constitute an Empire over nine million square miles in extent, afforded those at home an opportunity, surpassing all previous conception, of studying and comparing the natural history and resources of those distant lands, of which, attached though we might be individually to one or more of them by ties of friendship or of interest, the knowledge of many of us was of a very vague or partial character. To the Colonists who visited us last year, the Exhibition has been of inestimable value, in affording them a most favourable and appropriate opportunity of becoming acquainted or renewing their old friendship with the Mother Country, and of examining the pro- gress there made in industrial, educational, and commercial develop- ment ; in leading to the cultivation of intimacy between Colonists from different sections of the Queen's Dominions; and in afibrding them invaluable opportunities of comparing the resources and state of development of their respective countries with those of other parts of Europe. No more convincing illustrations than were provided by this great Exhibition could have been conceived of the importance, to the Home Country, to each Colony, and to India, of fostering in- timate relationship and unity of action. No more encouraging proof could have been afforded of the desire of all classes of Her Majesty's subjects at home to cultivate a knowledge of those far-off countries which the enterprise and perseverance of the British, and men of British offspring, have converted into prosperous and important Dominions, chiefly during the period of the Queen's reign, than was furnished by the interest which the thousands upon thousands, who H 2 100 Sir Fredericl Abel [April 90 came from all parts, displayed in the study of the instructive collections in the galleries at South Kensington. It was the success of the Exhibition which led to the definite formulation of the suggestion first made by your Eoyal Highness in a letter addressed by you in the autumn of 1884 to the Agents- General of the Colonial Governments, that a permanent representa- tion of the resources of the Colonies and India, and of their continu- ally progressing development, might with great benefit to the Empire at large, be established in this country. That the realisation of this idea upon a sufficiently comprehensive basis might constitute a worthy memorial of the accomplishment of fifty years of a wise and prosperous reign ; a memorial not personal in its character ex- cepting so far as it constituted an embkm of the love and loyalty of Her Majesty's subjects, but tending, as she would most desire, to serve the interests of the entire Empire, had only to be pointed out by your Eoyal Highness to be heartily concurred in by the Official Eepresentatives of the Colonies and India, who were so inti- mately identified with the triumphs of the recent Exhibition. The Committee to whom you. Sir, entrusted the elaboration of a scheme for carrying this conception into efi:ect, became persuaded by a careful consideration of the subject that such an Institution as your Eoyal Highness desired to see spring into life, to be a memorial really worthy of the Jubilee of Her Majesty's reign and to fulfil the great purposes which you had in view, must not be confined in its objects to particular portions of the Queen's Dominions, but must be made thoroughly representative of the interests and of the unity of the whole Empire. The outline of the scheme for the establishment of an Imperial Institute fur the United Kingdom, the Colonies and India, which met with the cordial approval of your Eoyal Highness, was necessarily concise in dealing with the very wide extent of ground which the operations of the Institute are intended to cover ; but those who have carefully considered it and rightly interpreted its proposals, have not failed to realise that it aims at very much more than the creation and maintenance of collections, illustrative of the natural resources of our Colonies and of India, and of the development and present con- dition of the chief industries of different parts of the Empire. One of the primary objects of the Institute will certainly be the establishment of thoroughly well selected, carefully arranged, and efficiently maintained representations of the natural products which constitute the treasures, and are emblematic of the im- portant positions in the Empire, of those great Colonial possessions which, during the fi.fty years of Her Majesty's reign, have, in many instances, experienced a marvellous development in extent, in commercial, social, and even in political importance.* The recent * Statistical statements illustratiag the development of the Colonies during the Queen's reign are appended. 1887.J on the Work of the Imperial Institute. 101 Exhibition not only afforded conclusive demonstration of the great icterest and value to the United Kingdom which must attach to such collections if properly organized ; by such illustrations as the magnificent collections of valuable woods, from nearly every Colony, many quite unknown in England, and the great variety of valuable economic products from India, of the existence of which we at home had little idea, it also served to convince us that our knowledge of the great countries which constitute the chief portion of the Empire is very limited and imperfect, and that their resources are in many direc- tions still in the infancy of development. Our Colonial Brethren cannot, on their part, fail to be greatly benefited by being thoroughly represented in a well-selected and carefully organised assemblage of illustrations of the sources of prosperity which constitute the sinews of their commerce, and upon a continued exploration and cultivation of which must depend the maintenance of their influence upon indus- trial and social progress. Neither can they fail to reap substantial advantages by pursuing a friendly rivalry with each other in demonstrating the advances made from time to time in the develop- ment of the resources of the respective portions of the Empire in which their lot is cast. The hearty co-operation and important material support to which the great Colonies, through, their representatives in London, pledged themselves when the scheme for the proposed Imperial Institute was in the first instance limUed to this branch of the great work which it is now contemplated to accomplish, afforded conclusive evidence of their earnest desire to be in all respects thoroughly represented in the Mother Country, and to take their places perma- nently in our midst as fellow-labourers in the advancement of the prosperity of the Empire. In furtherance of this important end, a notable feature of that building which, in its character, will, it is hoped, be worthy of the momentous epoch it is destined to com- memorate, will be, the attractions and conveniences presented by it as a place of resort and a rendezvous for Colonists visiting England, and, it is also anticipated, for the important Societies which represent the Colonies and Asiatic possessions in this Country, and the facilities which it will afford for reference to literature concerning the Colonies and India, for conferences on matters of common interest and value to the Colonists and those at home, for the interchange of information between the British manufacturer and those in the Colonies who are directly interested in meeting his requirements, and generally, for the cultivation of intimate relations and good fellowship between ourselves and our brethren from all parts of the Empire. The Institute will, however, not only operate actively under its own roof in j^romoting the cultivation of a better knowledge of the geography, natural history, and resources of our Colonies, and for the advancement of the interests of the Colonists in this Country ; it is also contemplated that representative collections of the natural products of the Colonies and India, carefully identified with the 102 Sir Fredericl Abel [April 22, more elaborate collections of the head establishment, shall be distributed to provincial centres, and that the provinces shall be kept thoroiighlv conversant with the current information from the Colonies and India, bearing upon the interests of the commercial man, the manufacturer, and the intending emigrant. Although the formation, and maintenance up to date, of collec- tions illustrative of the development and present condition of the important Industries of the Empire also forms, as I have stated, a part of the programme of the Institute, the scope of its activity in relation to industry will be of a much more comprehensive character ; indeed, it is to be hoped that the work which it will achieve in furtherance of the development and progress of industries and their future maintainance in the United Kingdom at least upon a footing of equality with their conditions in the great Continental States, will be most prominent in securing to the Imperial Institute the exalted position which it should occupy as the National Jubilee Memorial of Her Majesty's reign. There is no need for me to recall to the minds of an audience in the Eoyal Institution the great strides which have been made during the last fifty years in the applications of science to the purposes of daily life, to the advancement of commerce, and to the development of the arts and manufactures. Nor is it necessary to dwell uj^on the fact that this country is the birth-place of the majority of the great scientific and practical achievements which have revolutionised means of intercommunication, and have in other ways transformed the con- ditions under which manufactures, the arts and commerce are pursued. These very achievements, of which we as a Nation are so justly proud, have led, however, by many of their results, to our becoming reduced to an equality of position with other prominent Nations in regard to important advantages we so long derived from the possession in this country of great material resom-ces easy of access and application, and from the consequent pre-eminence in certain branches of trade and industry which we so long enjoyed. In 1852, Sir Lyon Play fair, in one of a course of most interesting lectures on some of the results of the preceding year's great Exhibi- tion, was impelled by the teaching of that great world's display, to point out that " the raw material, formerly our capital advantage, was gradually being equalised in price and made available to all by the improvements in locomotion," and " that industry must in future be supported not by a competition of local advantages, but by a com- petition of intellect." If this was already felt to be the state of the case six-and-thirty years ago, how much more must we be convinced of the full truth of this at the present day, by the conditions under which the British merchant and manufacturer have to compete with their rivals on the Continent and in the United States. It is still within the recollection of many that almost the whole world was in very great measure dependent upon Great Britain for its supplies of ordinary cast iron. Even as lately as 1871, the 1887.] on the Work of the Imperial Institute. 103 United States of America received from Great Britain nearly one- fiftli of its total produce of pig iron ; but from 1875 all importation of British iron ceased for over three years, and it was only in con- sequence of requirements in the States exceeding the capabilities of production, that some small demands arose in 1879, which were for some time maintained. But while, in 1879, the pig iron produced in the United States amounted to little over 3,000,000 tons, in 1882 the make had increased by 70 per cent., viz. to over 5,100,000 tons. Since that time the actual make has not increased (in 1885 it amounted to 4,529,869 tons of 2000 lb.), but the caijacity of production, which vitally interests the iron trade of this country, has risen enormously, the present capacity of all the American pig-iron works being estimated at over 8,900,000 tons, or nearly 300 per cent, greater than it was in 1879. So much regarding the United States ; looking nearer home, we find that the iron of France, Belgium, and Germany not only competes with ours in the open market, but that Belgian and German iron is actually imported into this country to a moderate extent. As an instructive illustration of the advance and influence of the improvements which have been made in intercommunication upon the value of our natural products and their importance even in our own industries, I may, on the authority of Sir Lowthian Bell, state the astounding fact that in the opinion of competent authorities, the ore (haematite) especially suitable for steel manufacture by the Bessemer process can be brought over sea a distance of 1000 miles, landed close to mines furnishing the cheapest made pig iron of Great Britain, and converted into steel rails at a lower cost than the native ironstone of Cleveland can furnish similar rails in iron. From time to time the ground which we have lost through the development of the resources of other countries has been more than retrieved temporarily by improvements effected through the more thorough comprehension and consequent better application of the scien- tific principles underlying processes of manufactui-e. Thus the quantity of fuel consumed in producing wrought-iron rails has been gradually reduced by improvements in the construction and working of furnaces, until less than one-half the amount is now required per ton of such rails than was employed fifty years ago ; but, remarkable as it may seem, the ultimate effect of an advance of this importance is actually to improve the position, in relation to this manufacture, of other Nations less favourably circumstanced than Great Britain in the matter of coal, for, instead of having to multiply any difference in our favour in the cost of fuel required to produce a ton of rails by twelve, that difference has now only to be multiplied by three in order to arrive at the extent of our advantage. The history of the development of steel manufacture during the last twenty-five years affords a most instructive illustration of the fluctuations which may ensue in the value of our natui'al resources, and the consequent condition of one or other of our important industries. 104 Sir Frederick Abel [April 22, arising out of continued advances made in the application of science to the perfection or transformation of manufacturing processes, and of the stimulating effects of such fluctuations upon the exertions of those who are able to bring scientific knowledge to bear upon the solution of problems in industrial operations which entirely baffle the ordinary manufacturer. Within that period the inventions of Bessemer and of Siemens have led to the replacement of iron by steel in some of its most extensive applications. The Bessemer converter, by which pig iron is rapidly transformed into steel by the injection of air into the molten metal, has, so far as this country is concerned, to a very great extent superseded the puddling furnace, in which pig iron is transformed by long-continued laborious treatment into steel or malleable iron. This important change in our national industry was, ere long, productive of a serious crisis therein, and for the reason that the pig iron produced from a large proportion of those ores which, from their abundance and the cheapness of their treatment, have been largely instrumental in placing Great Britain in her high position as an iron-producing nation, could not bo applied to the production of marketable steel by means of the Bessemer converter. In the purification of this pig iron during its conversion in the puddling furnace into a suitable material for the production of rails, the elementary constituent phosphorus, which it had carried with it from the ore as a contaminating ingredient very detrimental to its strength, was eliminated, and by sufficient treatment a malleable iron of good quality was obtained ; but in the production of steel from the same material in the Bessemer converter, the phosphorus is almost entirely retained in the metal, rendering it unsuitable for manufacture into rails or plates. Hence the applica- tion of this rapid steel-making process had to be chiefly restricted to particular kinds of ores, the supplies of which are limited to a few districts in this country. These had to be largely supplemented by importations from other countries ; nevertheless the cheapness of production and sui^eriority in point of strength, durability and lightness of the steel rails thus sent into the market from the Bessemer converter combined to maintain a supremacy of them over iron rails, &c., manufactured by the old puddling processes from the staple ores of the country. The advantages presented by steel over the wrought iron of the puddling furnace for constructive purposes speedily became evident ; combining as it does nearly double the strength with a more than proportionate superiority in elasticity and ductility, its value for ship- building purposes did not long fail to be realised. It was soon found more profitable to build a steel steamer, paying a price of nearly 9/. per ton for the material, than to construct one of iron which cost only 6/. 5s. per ton. The efiect of the rapid displacement of malleable iron by steel produced from ores of a particular class has been, that at least 85 to 90 per cent, of the iron ores of Great Britain could no longer be applied to the production of material for rails and for con- 1887.] on the Work of the Imperial Institute. 106 structive purposes, being unavailable for steel-making by any metliod which could compete with the Bessemer and Siemens processes. Great has been the apprehension among the owners of those ores, that the demand for iron which they can furnish could not revive, but the scientific metallurgist has successfully grappled, from more than one direction, with the great problem of restoring their commercial importance. Modifications of the mode of working the rival of the Bessemer process, namely, the open-hearth (Siemens-Martin) process, have given successful results in the production of serviceable rails con- taining higher proportions of phosphorus than had before been admissible, and a simple alteration of the method of carrying out the Bessemer process has, within the last few years, led to really triumphant results, with the employment of those ores which, before, could only be dealt with by the searching operation of the old puddling furnace. By utilising the basic character of lime during the treatment of the melted pig iron, yielded by phosphoric ores, with air in the Bessemer converter, the phosphorus is fixed at the moment of its elimination by oxidation from the metal, and the objec- tionable impurity is held bound in the slag, while a steel is obtained rivalling in freedom from phosjDhorus the product furnished by the pure varieties of English and foreign ore which alone could previously be successfully dealt with by the Bessemer process. This modified treatment of iron for the production of steel, called the hasic treatment^ was soon applied also to the open-hearth (the Siemens and Siemens- Martin) processes of steel-making ; thus a new era was established in steel manufacture by the quick processes, there being now but very few restrictions to their a^Dplication to iron produced from all varieties of ores. Indeed, the treatment is actually being applied profitably to the recovery of iron from the rich slag forming the refuse-product of the puddling furnace in the production of malleable iron, which, containing as it did the phosphorus eliminated from the pig iron by the laborious purifying treatment, had been condemned to limited usefulness as a material for road-making, while now it ranks in market value with some ores of iron. Yet another most interesting and valuable result has been achieved by this simple application of scientific knowledge. The slag or refuse-product of the basic treatment of iron contains, in the form of phosphates of lime and magnesia, the whole of the phos- phorus which it is the main function of that treatment to separate from the metal ; it was soon found that the phosphoric acid which had been produced by the elimination of the pernicious element in the conversion of bad iron into good steel, existed in this refuse slag in a condition as readily susceptible of assimilation by plants as it is in the valuable artificial manure known as superphosphate; the slag, simply ground up, constitutes therefore a manure which is already of recognised value and commands a ready sale at very profitable prices. The organisation of this latest advance in the development of 106 Sir FredericJ^ Abel [April 22. steel manufacture dates back only nine years, and already the year's product of tlie basic process amounts to orer l.SOO.OOO tons of steel. But althougli it is to Englishmen that the owner of iron property and the steel-maker are again indebted for these important results, and to English manufacturers that the first practical demonsti-ation of the success of this process is due. its application has been far more rapidly elaborated upon the Continent than here ; in Germany the importance of the subject was at once realised, and it is there that considerably the largest proportion of steel is produced by the basic treatment ; it is in Germany also that the value of the slag for agricultural purposes has been developed ; the first steps in its utilisa- tion here being but just now taken, in Stafiordshire. I have already referred to the remarkable strides which have been made in the extension of iron manufacture in the United States : the development there of steel production has been no less marvellous. In 1879, 928.000 tons of Bessemer steel were produced ; in 18S5 the make amounted to 1,701,000 tons, while the productive capacity in that year was estimated at 4,102,000 tons. tVith other extensive steel-producing works in course of completion, provision is being made for increasing the power of production by another million tons. Looking to the fact that at the present time the railway mileage in the United States exceeds that of the whole of Europe, there being 1,300,000 miles of railway in operation, while at the beginning of 1865 there were only 34,000 miles, the causes of this enormous development of the iron and steel manufacture are evident; the resources of the country in ore and fuel are gigantic, and the systematic technical training of the people has made its influence felt upon the development of this as of every other branch of industry which our friendly rivals pursue. But it is not only in the United States that the development in the production of iron and steel has greatly increased of late years ; thus, in Germany the increase in the production of pig iron alone, during the last twenty- one years, has been 287 per cent., in Austro-Hungary 152 per cent., while the increase in France and Belgium is 64 per cent., and therefore not greatly inferior to our own [To per cent.). Although, however, the increase in actual production of iron and steel in this country has not kept pace with that of some other countries, it is satisfactory to know that our productive power has very greatly increased in late years, and there is probably no one branch of our industries in which we have maintained our position so satisfactorily in regard to quality of product as that of iron and steel manufacture, even although, every now and then, we have indications that in the struggle with other Xations for superiority of product and for pre-eminence in continuity of progress, we have to look to our laurels. While this Country owes a deep debt of gratitude to such men as Xeilson, Mushet, Bessemer, Siemens, Thomas and Gilchrist, who by their brilliant discoveries and inventions have maintained Great Britain's posi- 1887.] on the Work of the Imperial Institute. 107 tion as the leader in the origination of successive eras of advance in iron and steel manufacture, there is no question that the trade generally has in recent years derived the greatest assistance and benefit from the organisation of the Society which, under the name of the Iron and Steel Institute, has brought the members of the trade to recognise that they themselves, and the country, reap incal- culable benefit from their free interchange of knowledge and the results of experience, their candid discussion of successes, failures, and diversities of views and practice — the combination of friendly rivalry with hearty co-operation in the advancement of the science and practice of their important calling. While we have succeeded in maintaining a foremost position in iron and steel manufacture, there are some other important branches of industry, for a time essentially our own, the present condition of which, in this country, we cannot contemplate with equal satisfaction. Several instructive illustrations might be quoted, but I will content myself with a brief examination of one of the most interesting. A glance at the history of the utilisation of some products of the distillation of coal will present to us an industry created and first elaborated in England, which has, on the one hand, by its develop- ment effected momentous changes in other industries and in im- portant branches of commerce, while on the other hand it has been in great measure wrested from us in consequence of the systematic collaboration of scientific and practical workers on the Continent. In discussing the recent advances made in chemical manufactures as exemplified by the Exhibition of 1851, Playfair, in the lecture to which reference has already been made, spoke of the great development of the value of the evil-smelling tar, which was then made to furnish the solvent liquids benzene and naphtha, and the antiseptic creosote, the residual material being utilised for pavements and for artificial fuel. The chemist little dreamt then that between 1851 and the year of the next gi-eat Exhibition, 1862, coal tar would have become a mine of wealth equally to science, to manufactures and to the arts, in which fresh workings have ever sinco continued to be opened up, and still present themselves for exploration. Hofmann, in his valuable report on the chemical products and processes elucidated by that Exhibition, dwells with the enthusiasm of the ardent worker in science upon the brilliant products obtained from coal tar, which had resulted from the labours of the scientific chemist and had already acquired an almost national importance, although this great industry was then still in its infancy. From the year 1856, when the first colouring matter known as ^auve, was discovered and manufactured by a young student at the College of Chemistry, ]\Ir. Perkin, one of HofmaLn's most promising pupils, to the present time, the produc- tion of new coal-tar colours or of new processes for preparing the known coloui's in gi'eater purity, has progressed uninterruptedly, this industry having long since become one of the most important, and 108 Sir Frederick Ahel [April 22, also one of the most remarkable, as illustrating by eacb stage of its development the direct application of scientific research to the attain- ment of momentous practical results. It is interesting to note that Perkin's discovery of mauve, as a product of one of the most important derivatives of coal-tar, called aniline, was arrived at in the course of an investigation, having for its object the artificial production of the invaluable vegetable alkaloid, quinine, the synthesis of which has been the aim of many researches during the past half century, and aj)pears to be at length about to be achieved, as the result of a long chain of scientific research. The difficulties to be overcome before mauve could be produced upon a manufacturing scale were very great, and were only solved by a steady pursuit of scientific research, side by side wdth practical experiments suggested by its results. Aniline — the parent of the first coal-tar colour, a liquid organic alkali — a most fertile source of interesting and important discoveries in organic chemistry, which have made the names of Hofmann and others famous — was produced with difficulty by various methods in very small quantities, so as to be almost a chemical curiosity at the time of the discovery of mauve. Among the substances from which it had been prepared was the volatile liquid known as benzene, first discovered in the laboratory of this Institution in 1825 by Faraday, in the liquid products condensed from oil gas, but afterwards obtained by Mansfield, in the College of Chemistry, from coal-tar naphtha, which also furnished in his hands a series of homologous liquids, many of them now of great importance as the raw materials from which dyes are obtained. The conversion of benzene into aniline, which had been efiected on a very small scale in different ways by German and Russian investigators, was accomplished as a manufacturing process after many difficulties by Perkin, and within a year after the discovery of mauve by him, it was in the hands of the silk dyer. Perkin's success led other chemists at once to pursue researches in the same direction, especially in France, where the next important coal-tar colour, magenta or fuchsine, was obtained, by M. Verquin, the successful manufacture of which in a pure state was, however, first accomplished by English chemists, with Mr. E. C. Nicholson at their head, whose magnificent specimens in the 18G2 Exhibition excited universal admiration. In 1861 beautiful violet and blue colours were produced, again by French chemists (Girard and De Laire), but were manufactured shortly afterwards in a pure state by Nicholson. This brought the coal-tar dye industry down to the year 1862, and Hofmann, in congratulating his young pupil Perkin (in his Jury Report) upon the splendid industrial result achieved, in having first manufactured a colour from coal-tar, which had been arrived at by purely scientific research, expressed the hope that the commercial success of his enterprise might not divert him from the path of scientific inquiry — a hope which he has lived to see fully realised, as the long scries of fresh contributions, made almost without inter- 1887.] on the Work of the Imperial Institute. 109 ruption since that time by Perkin to our knowledge of organic chemistry have been among the most brilliant and important achieved by chemists of the present day, and have continued to influence in a most important manner the branch of industry which he created. The six years succeeding those which formed the first period (1854-1862) of existence of this industry were fruitful, not only of new colours but also of progress made in England, as well as on the Conti- nent, in the development of the manufacture, and of our knowledge of the constitution, of the beautiful dyes which outvie each other in brilliancy. Important researches by Hofmann, which, while establish- iDg the correctness of his scientific conceptions of the real nature of magenta, led to the discovery, by him, of a matchless violet dye, were followed by the production, at the hands of Perkin and Nicholson in England, and of several workers on the Continent, of the well-known gas-light greens, of Bismarck brown, and of some eight or nine other important dyes ; blue, yellow, orange, and scarlet. In the next period of six years (1868-1874) another great stride was made in the coal-tar colour industry, due to important scientific researches carried out by two German chemists, Graebe and Liebermann, which led them, in the first place, to obtain an insight into the true nature of the colouring matter of one of the most important staple dye-stufi's, namely the Madder root. They found that this colouring matter which chemists call Alizarine was related to Anthracene, one of the most imporjtant solid hydrocarbons formed in the distillation of coal, a discovery which was speedily followed by the artificial formation of the madder dye, alizarine, from that constituent of coal-tar. At first, this achievement of Graebe and Liebermann was simply of high scientific interest, but Perkin, who was pursuing research in the same direction, soon discovered two methods by which the conversion of anthracene into the madder dye could be accomplished on a large scale, and one of these, which was also arrived at by the German chemists simultaneously wdth Perkin, is still used for the manufacture of alizarine, which was for some time most actively pursued in this country, with very momentous ]-esults, as regards the market value of the madder root. The latter has long been most extensively cultivated in Holland, South Germany, France, Italy, Turkey, and India, the consumption of madder in Great Britain having attained to an annual value of as much as 1,000,000/. sterling. Play- fair pointed out in 1852 that important improvements had been attained in the extraction of the red colour or alizarine from the madder root, the refuse of which, after removal of the dye in the ordinary way, had been made, by a simple treatment, to furnish further quantities of the colouring matter. This result, most valuable at the time of the first great Exhibition, became insignificant when once the dye was arti- ficially manufactured from anthracene ; the price paid for madder in 1869 was from 6d. to 8c?. per pound, but now the equivalent in arti- ficial madder dye, or alizarine, of one pound of the root, can be obtained for one-halfpenny. The latter is still used by the most conservative 110 Sir Frederick Abel [April 22, section of the dye-trade, the wool-dyers (and in some respects it appears to present in this direction a little advantage over the arti- ficial colour ), but the value of its present annual consumption in Great Britain has become reduced from one million to about •10,000/. During the development of the artificial alizarine industry within this third period of six years, the continued researches of Perkin, Schunck, Baeyer, Caro, and others have led to the development of further important varieties of coal-tar dyes, the most valuable of which, discovered by the two last-named chemists, was a beautiful cerise colour, called eosine. With the discovery of artificial alizarine the truly scientific era of the coal-tar industry may be said to have commenced, most of the commercially valuable dye-products, obtained since that time, being the result of truly theoretical research by the logical pursuit of definite well understood reactions. The wealth of discovery in this direction made during the last thirteen years is a most tempting subject to pursue, but I am compelled to refrain from entering upon it, further than to point out that the practical significance of beauti- ful scientific researches of many years previous became developed — that one of the results was the production of very permanent and brilliant scarlet and red dyes, the manufacture of which has greatly reduced the market value of cochineal — that the careful study of the original coal-tar colours led to their production in a state of great purity by new and beautifully simple scientific methods (which include the extensive employment as an invaluable practical agent in their production, of the curious gaseous oxychloride of carbon, until lately a chemical curiosity, produced through the agency of light, and hence christened phosgene gas, by its discoverer, John Davy, in 1812) ; and lastly, that even the well-known vegetable colouring matter, indigo, one of the staple products of India, now ranks among the colours synthetically obtained by the systematic pursuit of scientific research, from compounds which trace their origin to coal-tar. The rapid development of the coal-tar colour industry has not failed to exercise a very important beneficial influence upon other chemical manufactures ; thus, the distillation of tar, which was a comparatively very crude process, when, at the period of the first Exhibition, benzene, naphtha, dead-oil and pitch were the only products furnished by it, has become a really scientific operation, involving the employment of comparatively complicated but beautiful distilling apparatus for the separation of the numerous products which serve as raw materials for the many distinct families of dyes. Very strong sulphuric acid became an essential chemical agent to the alizarine manufacturer, and, as a consequence, the so-called anhydrous sulphuric acid, the remarkable crystalline body which was for many years prepared only in small quantities from green- vitriol, and of which minute specimens carefully sealed up in glass tubes were preserved as great curiosities in my student's days, is now 1887.] on the Work of the Imperial Institute. Ill made at a low price upon a very large scale by a beautifully simple process worked out in England, by Squire and Messell. The alkali and kindred chemical trades have been very greatly benefited by the large consumption of caustic soda, of chlorate of potash and other materials used in the dye manufactures, and the application of con- structive talent, combined with chemical knowledge, to the production of efficient apparatus for carrying out on a stupendous scale the scientific operations developed in the investigator's laboratory, has greatly contributed to the creation of a distinct profession, that of the chemical engineer. One of the most beneficial results of the rapid development of the coal-tar colour industry has been its influence upon the ancient art of dyeing, which made but very slow advance until the provision of the host of brilliant, readily applicable colours completely revolutionised both it and the art of calico printing. In endeavouring to furnish some idea of the magnitude of the coal-tar colour industry, I may state that the total value of the coal-tar colours produced in 1885 amounted to about 3,500,000/. The value of the alizarine and its related dyes which are used with it for obtaining various shades of colour, now amounts to about one-half of the total produce of the coal-tar colour industry. Their manu- facture in England in considerable quantities still continues, but it is a suggestive fact that the value of the artificial alizarine imported into this country from the Continent last year, wa,s 259,795/. Taking the average value of madder at od. pel' lb., and the cost of its equiva- lent in artificial alizarine at one-halfpenny, the quantity imported, if valued at 5d. per lb., would represent about 2,597,950/. I venture to think that it will be interesting at this point, to quote some words of prophecy included in Professor Hofmann's important ' Eeport on the Chemical Section of the Exhibition of 1862,' and to inquii'e to what extent they have been verified. In commenting upon one of the features of greatest novelty in that worlds show, the exhibition of the first dye products derived from coal-tar, he says : — " If coal be destined sooner or later to supersede, as the primary source of colour, all the costly dyewoods hitherto consumed in the ornamentation of textile fabrics ; if this singular chemical revolution, BO far from being at all remote, is at this moment in the very act and process of gradual accomplishment ; are vre not on the eve of profound modifications in the commercial relations between the great colour- consuming and colour-producing regions of the globe ? Eventualities, which it would be presumptuous to predict as certain, it may be per- missible and prudent to forecast as probable ; and there is fair reason to believe it probable that, before the period of another decennial Exhibition shall arrive, England will have learnt to depend, for the materials of the coloui's she so largely employs, mainly, if not wholly, on her own fossil stores. Indeed, to the chemical mind it cannot be doubtful, that in the coal beneath her feet lie waiting to be drawn forth, even as the statue lies waiting in the quarry, the fossil equiva- 112 Sir Frederick Abel [April 22, lents of the long series of costly dye materials for whicli sbe lias hitherto remained the tributary of foreign climes. Instead of dis- bursing her annual millions for these substances, England will, beyond question, at no distant day become herself the greatest colour- producing country in the world ; nay, by the strangest of revolutions, she may ere long send her coal-derived blues to indigo-growing India, her tar-distilled crimson to cocbineal-produciug Mexico, and her fossil substitutes for quercitron and safflower to China, Japan, and the other countries whence these articles are now derived. " Coal and iron, it has been said, are kings of the earth, and our latest chemical victories seem destined to add another vast province to the dominion of coal, and a fresh element of commercial predominance to its already powerful possessors." So far as concerns the displacement of madder, cochineal, quer- citron, safflower, and other natural dye materials from their positions of command in the markets of England and the world, Hofmann's predictions have been amply fulfilled, and it appeared, in the earlier days of the coal-tar colour industry, as though he would be an equally true prophet in regard to England becoming herself the greatest colour- producing country in the world. But, although Germany did little in the days of infancy of this industry, beyond producing a few of the known colours in a somewhat impure condition, many years did not elapse ere she not only was our equal in regard to the quality of the dyes produced, but, moreover, had outstripped us in the quantities manufactured and in the additions made to the varieties of valuable dyes sent into the market. The following is the estimated total value of coal-tar colours manufactured in the several producing countries as far back as 1878 : — Germany, 2,000,000/. ; England, 480,000Z. ; France, 350,000Z. ; Switzerland, 350,000Z. These figures show that the value of the make of colours in England was less than one-fourth that of Germany, and that even Switzerland, which, in competing with other countries industrially is at great natural dis- advantages, was not far behind us, ranking equal to France as producers. The superior j^osition of Germany in reference to this industry may be in a measure ascribable to some defects in the operation of our Patent Laws and to questions of wages and con- ditions of labour ; but the chief cause is to be found in the thorough realisation, by the German manufacturer, of his dependence for success and continual progress upon the active prosecution of scientific research, in the high training received by the chemists attached to the manufactories, and in the intimate association, in every direction, of systematic scientific investigation with technical work. The young chemists which the German manufacturer attracts to his works rank much higher than ours in the general scientific training which is essential to the successful cultivation of the habit of theoretical and experimental research, and in the consequent appreciation of, and power of pursuing, original investigations of a high order. Moreover, the research laboratory constitutes an integral 1887.] on the Work of the Imperial Institute. 113 part of the German factory, and the results of the work carried on by and under the eminent professors and teachers at the universities and technical colleges are closely followed and studied in then- possible bearings upon the further development of the industry. The importance attached to high and well-organised technical education in Germany is demonstrated not only by the munificent way in which the scientific branches of the universities and the technical colleges are established and maintained, but also by the continuity which exists between the different grades of education ; a continuity, the lack of which in England was recently indicated by Professor Huxley with great force. Nearly every large town in Germany has its "Real Schule," where the children of the public elementary schools have the opportunity, either by means of exhi- bitions or by payment of small fees, of receiving a higher education, qualifying them in due course to enter commercial or industrial life, or to pass to the universities or to the polytechnic or technical high schools, which, at great cost to the Nation, have been developed to a remarkable extent in recent years, and have unquestionably exercised a most beneficial influence uj)on the trade and commerce of the country. A most important feature in the development of these schools is the subdivision of the work of instruction among a large number of professors, each one an acknowledged authority in the particular branch of science with which he deals. Thus, at the Carlsruhe Polytechnic School — one of the very earliest of its kind — which was greatly enlarged in 18S3 — the number of professors is 41 ; and at Stuttgart the teaching staff of the polytechnic school amounts to 65 persons, of whom 21 are jjrofessors. The important part taken by the German universities in the training of young men for technical pursuits has often been dwelt upon as constituting a striking feature of contrast to our university systems. The twenty-four universities in the German Empire, each with its extensive and well-equipped science deiDartments and ample professional staff, contribute most importantly to the industrial train- ing of the Nation in co-operating with the purely technical schools. The facts specified in the Report of the Technical Education Commission that, in the session 1883-4, there were 400 students working in the chemical laboratories at Berlin, and that, during the same session, 50 students were engaged in original research at Munich (where the traditions of the great school of Liebig are worthily main- tained), illustrate the national appreciation of the opportunities pre- sented for scientific training ; and the expenditure of 30,000/. upon the physical laboratory, and 35,000/. upon the chemical department, of the New University of Strasbourg, serves to illustrate the unsparing hand with which the resources of the country are devoted to the pro- vision of those educational facilities which are the very life-spring of the industrial progress whence those resources are derived. In France, advanced education had been allowed to sink to a low ebb after the provincial universities had been destroyed in the great Vol. XII. (No. 81.) i 114 Sir Frederick Ahel [April 22, Eevolution, and the University of Paris had been constituted by the first Napoleon the sole seat of high education in the country. Before the late war, matters educational were in a condition very detrimental to the position of the country among Nations. There was no lack of educational establishments, but the systems and sequence of instruction lacked organisation. Since the war, France has made great efforts to replace her educational resources upon a proper footing. The provincial colleges have been re-established at a cost of 3,280,000/., and the annual budget for their support reaches half-a-million. The organisation of industrial education has now been greatly developed, though still not on a footing of equality with that of Germany. The practical teaching of science commences already in the elementary schools, and the groundwork of technical instruction is afterwards securely laid by the higher elementary schools, of which so many excellent examples are now to be found in different parts of France. Every large manufacturing centre has its educational establishment where technical instruction is provided, with special reference to local requirements ; the Institute Industriel, at Lisle, and the Ecole Centrale of Lyons, are examples of these. In order to render these colleges accessible to the best talent of France, more than 500 scholarships have been founded, at an annual cost of 30,000Z. The Ecole Centrale des Arts et Manufactures, of Paris, still maintains the reputation as the great technical university of the country, which it earned many years ago, and receives students from the provincial colleges, where they have passed through the essential training preliminary to the high technical education which that great institution provides. Switzerland has often been quoted as a remarkable illustration of the benefits secured to a Nation by the thoroughly organised education of its people. Far removed from the ocean, girt by mountains, poor in the mineral resources of industry, she yet has taken one of the highest positions among essentially industrial Nations, and has gained victories over countries rich in the possession of the greatest natural advantages. Importing cotton from the United States, she has sent it back in manufactured forms, so as to undersell the products of the American mills. The trade of watch- making, once most important in this metropolis, passed almost entirely to Switzerland years ago ; the old established ribbon trade of Coventry has had practically to succumb before the skilled com- petition of Switzerland, and although she has no coal of her own, Switzerland is at least as successful as France in her approj)riation of the coal-tar colour industry and her rivalry in rate of production with England, the place of its birth and development. Comparative cheapness of labour will not go very far to account for these great successes ; they undoubtedly spring mainly from the thoroughly organised combination of scientific with practical education of which the entire people enjoys the inestimable benefit. 1887.] on the Work of tlie Imperial Institute. 115 From the age of six to twelve, or thirteen, the children must attend primary schools, where, as the pupils advance in age, the instruction becomes more practical. The application of the know- ledge acquired in these primary schools, is cultivated for three years at the so-called " Improvement Schools," and uj)on these follow the Cantonal High Schools, which are divided into trade- and classical schools, and of which there are sixtj^-seven in the little canton of Zurich alone. Above those there are five universities and the Zurich Technical Institute, which is supported by the Federal Government, the Canton itself subscribing liberally to its aid. It owns a very numerous staff of professors and teachers, and the number of students attending is so large that, magnificent as was the accommodation which it already afl'orded, no less than 50,000/. have recently been spent upon additional chemical laboratories. Although the Germans have so many technical colleges and chemical schools they go in large numbers to the Zurich Institute, and even a few English appreciate the great advantages which must accrue from the thorough training attainable in this world-renowned school of technics. Holland furnishes another brilliant example of the success with which a Nation can bring the power of systematic technical education to bear in securing and maintaining industrial victories in the face of most formidable disadvantages, while the United States of America, so rich in natural resources, have long since realised the immensity of additional advantages to be gained dver European Nations in the war of industry by a wide diffusion and thorough organisation of technical education. So long as forty years ago the States already possessed several excellent educational institutions established upon the basis of the Continental polytechnic schools, but it was not until about fifteen years later that the great advances achieved by Ger- many in technical education, made America, like France, anxious con- cerning the progress and development of some of her industries. The subject was at once made a thoroughly national one, and it is now just upon a quarter of a century ago since Congress ordained that each State should provide at least one college, having for its leading objects the diffusion of scientific instruction in its relations to the industry of the country, and decreed that public lands should be granted to the States and Territories providing such colleges. In accordance with the system adopted for the regulation of these grants, the State of New York received close upon a million acres of land, and out of this grant grew the University of Cornell, which could be called upon to educate 500 students free of charge under the conditions of the grant, and which was already at work in 1867, having in the meantime received most important aid from an endowment of 100,000Z. by a private citizen, Mr. Cornell. The combined effect of this State action and of great private munifi- cence, was a remarkably rapid development of scientific and technical education throughout the country ; besides some fifty colleges, with I 2 116 Sir Frederich Abel [April 22, eight or nine thousand students, whicli sprang out of the Land Grant Act for Industrial Education, there are now in the States about 400 other universities and colleges (with 35,000 students, and between 5000 and 6000 teachers), in a large j)roportion of which efficient instruction in applied science is provided. Among the more prominent of America's technical schools are the Stevens Institute of Technology, New Jersey ; the Pennsylvania Polvtechnic College, Philadelphia ; the Lawrence Science School, in connection with Harvard University ; the Columbia College and School of Mines, New York; the Massachusetts Institute of Tech- nology, Boston ; the Engineering School of the Michigan University ; the Lafayette College, Pennsylvania ; the Mechanical College of Louisiana University ; the Brown University, Ehode Island ; Wash- ington College, Virginia; Union College, Schenectidy; and the Shipley School, in connection with the Cornell University. To the useful work accomplished within a few years by these and many other highly important educational institutions, which have placed the acquisition of scientific knowledge within the reach of the very humblest, the enormous strides made by the United States in the development of home industries must unquestionably be in the main ascribed. While extolling the comprehensive and well-organized systems of technical education existing in all parts of the Continent and the United States, let us not undervalue the great progress which has been made in recent years in Great Britain in the advancement and extension of technical instruction. The Royal Commission on the Depression of Trade and Industry state, as the result of evidence collected by them, that " It would be difficult to estimate the extent to which our industries have been aided in various ways by the advance of elementary, scientific, and technical education during the last twenty years." The important influence exercised by the admirable work which the organisation of the Science and Art Department has accomplished, upon the intellectual and material progress of the Nation, is now thoroughly recognised. Professor Huxley, the Dean of the Normal School of Science, in his recent important letter " On the organisation of industrial education," has reminded us that " the classes now estab- lished all over the country in connection wdth that department, not only provide elementary instruction accessible to all, but ofier the means whereby the pick of the capable students may obtain in the schools at South Kensington as good a higher education in Science and Art as is to be had in the country," and " that it is from this source that the supply of science and art teachers is derived, who in turn raise the standard of elementary education " provided by the School Boards. The extension of facilities for the education of those engaged in art-industries is constantly aimed at, as was recently demonstrated by the creation of free studentships for artizans in the Art Schools at South Kensington. 1887.] on the Work of the Impel ial Institute. 117 The necessity wliicli has gradually made itself felt in the manu- facturing towns of the United Kingdom for encouraging the study of science in its apjjlication to industries, by those who intend to devote themselves to some branch of manufacture or trade, has led to the establishment in about twenty-five towns in England and Scotland, and in two or three in Ireland, of colleges of science corresponding more or less to the Continental polytechnic schools, and accomplishing important work in training students in the different branches of science in their applications to manufactures and the arts. A number of these, such as the Owen's College, Manchester, the Yorkshire College, at Leeds, the Glasgow and Bradford Technical Colleges, the Firth College at Sheffield, and the Mason's College at Birmingham, have established a high reputation as schools where science in its applications to productive industries is most efficiently taught and iiuportanlly advaucL-d. The Wealthier of the City Companies, some of which had long been identified with important educational establishments, associated themselves with the Corporation of the City of London nearly ten years ago to establish an organisation for the advancement of technical education, which has already carried out most important work. The Society of Arts, which initiated the system of examinations, afterwards so successfully developed by the Science and Art Department, set on foot and conducted for several years examinations of artizans in a few branches of technology. This useful work was relinquished in 1879 to the City and Guilds' Institute, and its extension since that period has been most satisfactory. The number of candidates then pre- senting themselves was 202, distributed over twenty-three centres where examinations were held, four years afterwards (1883) the number presenting themselves for examinations was 2397, and last year they amounted to 4764. The centres where examinations are held have been increased to 186, and the number of subjects dealt with, from thirteen to forty-eight. The beneficial influence exercised by these examinations upon the development and extension of technical instruction in the manufacturing districts throughout the country is already very marked. The adoption of the system, originated by the Science and Art Department, of contributing to the payment of teachers in proportion to the successes attained by their pupils, is operating most succesfully in promoting the establishment and extension of classes for instruction in technical subjects, in connexion with Mechanics' Institutes and other educational establish- ments in various centres of industry. In 1884, the number of classes in different parts of the country and metropolis which are connected with the examinations of the Institute was 262, having 6395 students, and this year the number of classes has risen to 357, and that of students to 8500. The Technical College at Finsbury was the first great practical outcome of the efforts made by the City and Guilds' Institute to supplement existing educational machinery, by the creation of techno- 118 Sir Frederick Ahel [April 22, logical and trade schools in the metropolis, and the results, in regard to number and success of students at the day and evening schools of that important establishment, have afforded conclusive demonstra- tion of the benefits which it is already conferring upon young workers who, with scanty means at their command, are earnest in their desire to train themselves thoroughly for the successful pursuit of industries and trades. The evening courses of instruction are espe- cially valuable to such members of the artizan classes as desire, at the close of their daily labour, to devote time to the acquisition of scientific or artistic knowledge. The system of evening classes, which was pursued, in the first instance, at King's College and one or two other metropolitan schools, was most successfully developed by the Science and Art Department, and, being now sujDplcmented by the important work accomplished at Finsbury College, is really, in point of organisation, in advance of similar w^ork done in other countries. Another department of the City and Guilds' Institute, of a some- what difi"erent character, but akin to that of the Finsbury College in the objects desired to be achieved by it, is the South London School of Technical Art, which is also doing very useful work, while the chief or central Institution for Technical Education, which com- menced its operations about tliree years ago, if it but continue to be developed in accordance with the carefully matured scheme which received the approval of the City and Guilds' Council, and with that judicious liberality which has been displayed in the design and arrangement of the building, bids fair to become the Industrial University of the Empire. As one of the first students of that College of Chemistry which became part-parent of our present Normal Schools of Science, and the creation of which (forty-two years ago) constituted not the least important of the many services rendered towards the advancement of scientific education in this country by His Royal Highness the Priuce Consort, most vividly I remember the struggling years of early existence of that half-starved but vigorous ofispring of the great school of Liebig, born in a strangely unsympathetic land in the days when the student of science in this country still met on all sides that pride of old England, tbe practical man, enquiring of him complacently : cui bono ; quo bono ? That ardent lover of research and instruction, the enthusiastic and dauntless discii)le of Liebig — my old master — Hofmann, loyally supported through all discouragement, and in the severest straits, by a small band of believers in the power of scientific research to make for itself an enduring home in this country, suc- ceeded in very few years in develoj)ing a prosperous school of chem- istry which soon made its influence felt upon British industry ; and it is not credible that less important achievements should be accom- plished, and less speedily, in days when the inseparable connection of science with j^ractice has become thoroughly recognised, by an Insti- tution created, and launched under most auspicious circumstances, by those powerful representatives of the commercial and industrial 1887.] on the Work of the Imperial Institute. 119 prosperity of tlie Empire, who, before all others, must realise the vital necessity for ceaseless exertions, even for much self-sacrifice in the immediate present, to recover our lost ground in the Dominions of Industry. It has been already demonstrated by the rapid increase which has taken place in the number of young men who, qualified by their pre- liminary education for admission as matriculated students, go through the complete curriculum of the Central Institute, that the combina- tion of advanced scientific instruction with practical training which that course of study involves, will be much sought after by young men whose preliminary education has qualified them for admission, and whose probable future career will be interwoven with the advance- ment of one or other of the great industries of our country. But, one of the most important functions of the Central Technical College shou'd consist in the thorough training of teachers of aj^plied science. The statistics furnished by the technological examinations show that, while their successful organisation has led to the establishment of classes of instruction, supplementary to the general science teaching in every large manufacturing centre, the increase in the number of candidates examined has been accompanied by an increase in the per- centage of failures to pass the examinations, and that the supply of a serious deficiency in competent teachers was essential to a radical improvement in technical education. The work of the City and Guilds' Institute in this direction has already been well begun, and it is in the furtherance of this, by the organisation of arrangements for facilitating the attendance of science teachers for sufScient periods at the Central Institute, or at more accessible provincial technical colleges, that the Imperial Institute may hope to do good work. Without taking any direct part in the duty of education, it is contemplated that the Imperial Institute will actively assist in the thorough organisation of technical instruction, and its maintenance on a footing, at least of equality, with that provided in other countries, by the system of intercommunication which it will establish and maintain between technical and science schools ; by the distribution of information relating to the progress of technical education abroad, to the progressive development of industries, and the requirements of those who intend to pursue them ; by the pro- vision of resources in the way of material for experimental work, and illustrations of new industrial achievements, and by a variety of other means. The provisicm of facilities to teachers in elementary schools to improve their knowledge of science and their power of imparting information of an elementary character to the young, with the aid of simple practical demonstrations of scientific principles involved in the proceedings of daily life, constitutes another direction in which important progress may be made towards establishing that continuity between elementary and advanced education which is so well developed on the Continent. The organisation of facilities, combined 120 Sir Frederick Ahel [April 22, with material aid, to bo provided to young artizans who shall afford some legitimate evidence of superior natural intelligence and a striving after self-improvement, to enable them to abandon for a time the duty of bread-winning, and to work at one or other of the technical schools in London or the provincial centres, will be another object to which the resources of the Im23erial Institute should be applied very beneficially. Not only will the intelligent workman's knowledge of the fundamental principles of his craft or trade be thereby promoted ; his association in work and study with others who are pursuing the acquisition of knowledge in different directions, which at first seem to him alien to his personal pursuits and tastes, but come in time to acquire interest or importance in his eyes, will bring home to him the advantages of a wider and more comprehensive scope of instruction, and the enlargement of his views regarding the value and pleasure of knowledge will, in turn, exercise a favourable influence in the same direction upon those with whom he afterwards comes into contact. The cramping influence which the great sub- division of labour, resulting from the development of mechanical, physical, _and chemical science, is calculated to favour, must thus become counteracted, and the workman will realise, that if he is to rise above the level of the ordinary skilled labourer, mere dexterity in the particular branch of that trade which he has made his calling must be supplemented by an acquaintance with its cognate branches, by some knowledge of the principles which underlie his work, and by some familiarity with the trades allied to his calling. The importance of bringing technical instruction wdthin the reach of the needy scholars of the lower middle class need not be dwelt upon, and there can be no question that one of the most powerful means of promoting the extension of technical education will be the well organised administration of a really comprehensive system of scholarships, to be judiciously utilised in connection with the well- established colleges and schools of science and technics throughout the country, in such proportions as to meet local requirements and changing conditions. That a good foundation for such a system of scholarships is likely ere long to emanate from the resources of the Eoyal Commission of 1851, has already been officially indicated in one of its reports ; may we not also hope that many will be found in our Empire ready to follow the example of the late Sir Joseph Whit- worth, and to act in emulation of the patriotism of those men w^ho, by munificent donations or endowments in aid of the work of bringing industrial education within the reach of all classes in the United States, have helped to place our Cousins in the position to hold their own and aspire to victory, in the war of industry ? The thoroughly representative character which it is intended to maintain for the governing body of the Imperial Institute, will secure the wise ad- ministration by it of funds of this kind, dedicated to the extension and perfection of national establishments for technical education, and to the encouragement of its pursuit, in the ways above indicated, by 1887.] on the Work of the Imperial Institute. 121 those whose circumstances would otherwise prevent them from en- joying the advantages secured to their fellow- workers in other countries. Several other directions readily suggest themselves in which the judicious administration of resources in aid of the technical training of eligible men of the artizan class could well form part of the organised work of the Imperial Institute. By the establishment of an Education branch of the Intelligence Department, which will form a very prominent section of the Imperial Institute, the working of the colleges and schools of applied science in all parts of the United Kingdom will be harmonised and assisted, and the information continuously collected from all countries relating to educational work and the application of the sciences to industrial purposes and the arts will be systematically distributed. A well- organised Enquiry Department will furnish to students coming to Great Britain from the Colonies, Dependencies and India the requisite information and advice to aid them in selecting their place of work and their temporary home, and in various other ways. The collec- tions of natural products of the Colonies and India, maintained up to the day by additions and renewals at the central establishment of the Institute, will be of great value to students in the immedi- ately adjacent educational Institutions, and will moreover be made subservient to the purposes of provincial industrial colleges by the distribution of thoroughly descriptive reference catalogues, and of S23ecimens. Supplies of natural products from. the Colonies, India, or from other Countries, which are' either new or have been but imperfectly studied, will be maintained, go that material may be readily provided to the worker in science or the manufacturer, either for scientific investigation or for purposes of technical experiment. The existence of those collections and of all information re- lating to them, as well as of the libraries of technology, inventions, commerce and applied geography, in immediate proximity to the Government museums of science and inventions, art, and natural history, to the Normal School of Science, and to the Central Technical Institute, present advantages so obvious as to merit some fair con- sideration by those who have declined to recognise any reason in favour of the establishment of the Imperial Institute at South Kensington. In the powerful public representations which have of late been made on the imperative necessity for the greater dissemination and- thorough organisation of industrial education, the importance of a radical improvement in commercial education, as distinguished from what is comprehended under the head of technical training, has scarcely received that prominence which it merits. It is true that, in some of our colleges, there are courses of instruction framed with more especial reference to the requirements of those who propose to enter into mercantile houses, or in other ways to devote themselves to commercial pursuits ; but as a rule the mercantile employes, embraced under the comprehensive title of clerks, begin their careers in life but 122 Sir Frederick Abel [April 22, ill prepared to be more than mechanical labourers, and remain greatly dependent upon accident, or uipon their desire for self- improvement which directs them in time to particular lines of study, for their prospects of future success in commercial life. This impressed itself strongly upon the Eoyal Commission on the Depression of Trade and Industry, who state as the result of evidence collected by them that our deficiency in the matter of education as compared with some of our foreign comj^etitors relates " not only to what is usually called technical education, but also to the ordinary commercial education which is required in mercantile houses." The ordinary clerk in a merchant's office is too often made to feel his inferiority to his German colleague, not merely in regard to his lamentable deficiency in the knowledge of languages, but in respect to almost every branch of knowledge bearing upon the intelligent performance of his daily work and upon his prospect of advancement in one or other branch of a mercantile house. The preliminary training for commercial life on the Continent is far more compre- hensive, j)ractical and systematic than that which is attainable in this country, and the student of commerce abroad has, afterwards, oppor- tunities for obtaining a high scientific and practical training at distinct branches of the polytechnic schools and in establishments analogous to the technical colleges, such as the High Schools of Commerce in Paris, Antwerp, and Vienna. It will be w^ell within the scoj)e of the Imperial Institute as an organisation for the advancement of industry and commerce, to pro- mote a systematic improvement and organisation of commercial education by measures analogous to those which it will bring to bear upon the advancement of industrial education. The very scant recognition which the great cause of technical edu- cation has hitherto received at the hands of our administrators has, at any rate, the good effect of rousing and stimulating that power of self- help which has been the foundation of many achievements of greatest pride to the Nation, and we may look with confidence to the united exertions of the people of this country, through the medium of the representative organisation which they are now founding, for the early development of a comprehensive national system of technical education, of the nature foreshadowed not long since by Lord Harrington, in that important address which has raised bright hopes in the hearts of the Apostles of education. In some of the views which have been of late put forward regard- ing the possible scope of the Imperial Institute, the antagonism which has been raised and fostered against its location in the vicinity of some of our National Establishments most intimately connected with the educational advancement of the Empire, has developed a tendency to circumscribe its future sphere of usefulness, and to place its functions as a great establishment of reference and resort for the commercial man in the chief foreground. I have endeavoured to indicate directions in which its relations to the Colonies and India. 1887.] on the Wovh of the Imperial Institute. 123 to the great industries of the country, and to the advancement of technical and commercial education, cannot fail to be at least as im- portant as its immediate connection with the wants of the commercial section of the community, and those are most certainly quite indei^en- dent of the particular locality in which it may be placed, excepting in so far as the command of ample space, and the advantages to be derived from juxta-position with the great National establish- ments to which I have referred, is concerned. At the same time, there is not one of the directions in which the development of the resources and activity of the Institute has been thus far indicated, which has not an immediate and im}3ortant bearing upon the advance- ment of the commerce of the Empire. There are, however, special functions to be fulfilled by the Institute, which are most immediately connected alike with the great commercial work of the City of London and with that of the provincial centres of commerce. The provision, in very central and readily accessible j)Ositions, of com- mercial museums or collections of natural or import products, and of ex]3ort products of different nations, combined with comprehensive sample-rooms and facilities for the business of inspection or of commercial, chemical or physical examination, is a work in which the Institute should lend most important aid. The system of corre- spondence with all parts of the Empire which it will develop and maintain will enable it to collect, and form a central depot of, natural products from which local commercial museums can be supjolied with comj^lete, thoroughly classified economic collections, and with repre- sentative samples of all that, from time to time, is new in the way of natural products from the Colonies and Dependencies, from India, and from other countries. In combination with this organisation, the distribution, to commercial centres, of information acquired by a central department of commercial geography will constitute an im- portant feature in the work of the Institute, bearing immediately upon the interests of the merchant at home, in the Colonies, and in India. The formation of specially commercial institutions, of which enquiry offices, museums, and sample rooms with their accessories, will form a leading feature, and which will supply a want long since provided for by the Nations with whom we compete commercially, is already in contemiDlation in the Cities of London and Newcastle ; other great commercial centres will also doubtless speedily take steps to provide accommodation for similar offshoots from the central collections of the Institute. So far as the Indian Empire is con- cerned, the organisation of correspondence by provincial committees which already exists in connection with economic and geological museums established in the several Presidencies, affords facilities for the speedy elaboration of the contemplated system of corresjiondence in connection with the Institute, and the establishment of similar organisations in the different Colonies will, it is hoped, be heartily entered ujjon and speedily developed. 124 Sir Frederick Abel [April 22, The system of correspondence to which I have more than once alluded in indicating some of the work of the Institute, in relation to technical education and industry, and which will form a most important part of the main groundwork of its organisation, is not in the least theoretical in its character. Its possible development has suggested itself to many who have given thought to the future sphere of action of the Institute in connection with commerce and industry ; to myself, who for many years have been, from time to time, officially cognizant of the work performed by what are called the Intelligence Departments of the Ministries of War abroad and at home, the direct and valuable bearing of such a system upon the work of the Institute, suggested itself as soon as I gave thought to the possible future of this great conception, and to Major Fitzgerald Law belongs the credit of suggesting that the well-tried macliinery of the War Office Intelligence Department should serve as a guide for the elaboration of a Commercial Intelligence Department. This Department, which will, it is hoped ere long commence its operations by establishing relations with the chief Colonies and India, will be in constant communication with the Enquiry Offices to be attached to the local commercial establishments and to other provincial representations of the work of the Institute, systematically distributing among them the commercial information and statistics continually collected. It will be equally valuable to the Colonies and India by bringing their requirements thoroughly to the knowledge of the business men in the United Kingdom, and by main- taining that close touch and sympathy between them and the people at home which will tend to a true federation of all parts of the Empire. In no more important direction is this system destined to do use- ful work than in the organisation of emigration, not only of labour, but also of capital. The establishment of emigration enquiry offices at provincial centres in connection with a central department at the Institute, will be of great service to the intending emigrant, by placing within his reach the power of acquiring indisj)ensable in- formation and advice, and by facilitating his attainment of the special knowledge or training calculated to advance his prospects in the new home of his choice. Similarly, the capitalist may be assisted in dis- covering new channels for enterprise in distant portions of the Empire, the resources of which are aw^aiting development by the judicious application of capital and by the particular class of emigra- tion which its devotion to public works or manufacturing enterprise in the Colonies would carry wdtli it. The extent to which the State may aid in the organisation of systematic emigration, and the best mode in which it may, without burden to the Country, promote the execution of such public works in the Colonies as will open up their Dominions to commerce and at the same time encourage the par- ticular class of emigration most advantageous to the Colonies themselves, are subjects of great present interest ; but, in whatever way these imj^ortant questions may be grappled with, such an or- 1887.] on the Work of tlie Imperial Institute. 125 ganisation as the Institute slioiild su^Dply, cannot fail to accelerate the establishment of emigration upon a sound and systematic footing, and to co-operate very beneficially in directing private enterprise into the channels best calculated to advance the mutual interests of the capitalists and the Colonies. I have already indicated that it is not only in connection with purely commercial matters that the Intelligence Department of the Institute will occupy itself. The prospects of its value to the Colonies and to India in promoting the development of their natural resources and the cultivation of new fields for commercial and in- dustrial activity are well illustrated by the valuable work which has been accomplished upon similar lines by the admirably directed organization at Kew. By the systematic collection and distribution of information relating to industries and to education from all countries which compete with ourselves in the struggle for supremacy in intellectual and industrial development, the Institute will most importantly con- tribute to the maintenance of intimate relationship and co-operation between educational, industrial, and commercial centres, between the labourer in science and the sources through which his work becomes instrumental in advancing national prosperity ; between the Colonies and the Mother-Country, between ourselves and all Races included in the vast Empire of Her Majesty. In conclusion, I venture to express the belief that the organisation which the Imperial ' Institute will have the power of developing, with a wisely constituted governing body at its head, may accomplish, and at no distant date, most useful work, which has been already publicly indicated as destined to have an immediate bearing upon the federation of England and her Colonies. Professor Huxley, in his last Presidential Address to the Eoyal Society, uttered most suggestive words, indicative of the value and the possibility of a scientific federation of all English speaking Peoples ; and this subject is now receiving the careful consideration of that Society. It is firmly believed by leading men of science, that such a federation of at any rate the Colonies and Dependencies with us will be brought about, and it is in harmony with that belief that the Imperial Institute should be expected, through its organisation, to afford important aid in the application of the principle of federation to the geological and topographical survey of the Colonies, in the establishment of a system of interchange of meteorological and scientific observations, and in the -promotion, in various ways, of thorough co-operation between particular Colonies or groups of Colonies, for applying the results of scientific research to the mutual development of their natural resources. It may be that the programme of which I have given a very im- perfect exposition, as indicative of the work which the Imperial Institute may be called upon to accomplish, will be regarded as almost too ambitious in its scope for practical fulfilment. The outline 126 Sir Frederick Abel [April 22, of this programme has been drawn by a combination of abler hands than mine ; I have but ventured to sketch in some of the details as they have presented themselves to my mind, and to the minds of ethers who have given thought to this great subject ; but I dare to have faith in its realisation, and to believe that, if the work be taken in hand systematically and progressively, the nucleus being first thoroughly established from which fresh lines of dejDarture will successively emanate, the Imj^erial Institute is destined to become a glory of the land. And, as one whose mission it has been, through many years of arduous work, to assist in a humble way in the ajDplica- tion of the resources of some branches of science to the maintenance of the country's power to defend its rights and to hold its ow^u, I may perhaps be pardoned for my presumption in giving expression to the firm belief that, by the secure foundation and careful developmeut of this great undertaking, and by its wise direction by a Government truly representative of its Founders — all Nations and Classes com- l^osiug the Empire — there will be secured in it one of the most important future Defences of the Queen's Dominions ; one of the most powerful instruments for the maintenance of the unity, the strength, and the prosperity of Her Realms. At the conclusion of the address, the Prince of Wales said : — " Ladies and Gentlemen, — Having had the honour of occupying the Chair this evening, I think we ought not to separate without my expressing, on your part as well as on my own, our deep sense of grati- tude for the interesting and exhaustive lecture which Sir Frederick Abel has just given us. You are well aware of the great interest I take in this Imperial Institute, as I am anxious that it shall be a memorial of the Jubilee of Her Majesty the Queen, and at the same time a memorial which shall be of great use to this country, and cement still further the good feeling which I trust has always existed in the Mother Country towards our Colonies and India. Sir Frederick Abel has, I think, touched on all the salient points with regard to the Imperial Institute, so that it will be needless for me to say anything further. But I thank him very much again for having given us this lecture this evening, and I feel sure that those who have been here and who did not feel conversant with the subject, will carry aw^ay with them a very clear understanding of what the objects of the Institute are." (Cheers.) 1887.] on the Work of the Imperial Institute. 127 THE BRITISH COLONIES. Illustrations of their Development during the Queen's Reign. Australii Africa IMPOETS AND EXPORTS. IMPOKTS. EXPORTS. (1837 . an Dependencies . . .. I ( 18S5 . 5,2071,000 . 25,700,000 5,000,000 21,500,000 ( 1837 . lasia < (1885 . . 1,500,000 . 63,500,000 1,300,000 52,000,000 ( 1837 . (1885 . . 2,000,000 1,500,000 . 10,000,000 12,000,000 All the Imports and Exports taken together were ELEVEN TIMES larger in 1885 than they were in 1837. T^ -ri Qi.- • rr , -.1 m • S^^^'^ " 3, 700, 000 tons. British Shipping Trade with Colonies . . < (1885 .. 56,000,000 „ ^ . . , ^ ., , . ^1837 .. 11,300,000^. British Export to Colonies < (1885 .. 54,500,000?. POPULATION. Of all the Colonies existing in 1837 •• < *' ' ' (1881 .. 12,753,277* Of all the Colonies in 1881 15,703,072* * These numbers must have considerably increased since 1881. RATE OF INCREASE FROM 1837 TO 1881. In European Colonies SLIGHT. In Ceylon TWICE as large as it was. In the Great Asiatic Colonies ,. About the SAME. In the Cape of Good Hope .. .. EIGHT TIMES as large as it was. In Canada THREE TIMES as large as it was. In the West Indies NOT quite TWICE as large as it was. In Australia Nearly TWELVE times as large as it was. (Compiled in the British Isles Indian Empire (including Burmah) Dominion of Canada :- Quebec Ontario New Brunswick Nova Scotia British Columbia Manitoba North-West Territories Prince Edward's Island Newfoundland Australasia : — New South Wales . . Victoria South Australia.. Queensland Western Australia .. Tasmania New Zealand Fiji New Guinea South Africa : — Cape of Good Hope . . Bechuanaland . . Natal St. Helena Ascension Ceylon . . Mauritius Straits Settlements Hong Kong Port Hamilton British North Borneo . . Labuan British Guiana West Indii'S : — Jamaica Trinidad Windward Islands Leeward Islands Bahamas Bermudas British Honduras West Africa : — Sierra Leone Gambia Gold Coast .. .. Lagos Gibraltar Malta Cyprus Heligoland Falkland Islands . . How AND WHEN ACQUIRED. Conquest, Treaty Cession Treaty Cession Conquest, Treaty Cession Transfer to Crown Settlement Charter to Company . . Conquest Settlement,Treaty Cession Settlement Settlement Settlement Settlement Settlement Settlement Purchase Cession from Natives . . Annexation Treaty Cession ^finally) Annexation Conquest Annexation Treaty Cession Conquest and Cession . . Treaty Cession Treaty Cession Cession to Company Treaty Cession Conquest and Cession . . Conquest Conquest Cession Settlement Settlement Conquest Transfer from Company Conquest and Cession .. Cession Conquest Treaty Cession Convention with Turkey Treaty Cession Treaty Cession Area. Square Miles. 120,832 1757-1858 1759-63 1763 1627-1713 1858 1813 1670 1756-63 1550-1713 1787 1834 1836 1824 1826 1803 1840 1874 1884 1815 1885 1843 1673 1815 1801 1810-14 1785-1824 1841 1884 1877 1847 1803-14 1655 1797 1783 1629 1612 1798 1807 1663-1871 1861 1704 1814 1878 1814 1770 1,574,516 3,470,392 40,200 311,098 87,884 903,690 668,497 1,060,000 26,215 104,458 7,740 86,360 219,700 185,000 18,750 3,255,942 4,362 1,754 784 665 5,390 468 69 18,784 1,069 423,450 45 37 25,365 713 1,472 80 5 30,000 30 109,000 12,955 19 6,400 20,390 2 119 3,584 1 6,500 9,101,999 OF THE BRITISH EMPIRE. Spring of 1886.) Population. 35,241,482 253,982,595 4,324,810 585,536 153,128 311,413 119,516 43,521 60,546 14,150 408,070 75,270 Imports. Total. £390,018,569 179,509 921,268 961,276 312,781 309,913 31,700 130,541 564,304 128,614 135,000 424,495 3,495,397 1,674,319 5,024 200 2,763,984 377,373 540,000 160,402 2,000 150,000 6,298 264,061 1,213,144 13,948 27,452 558,036 18,381 149,782 186,173 2,001 1,553 305,337,924 Total. 68,156,654 23,917.200 1,682,457 22,826,985 19,201,633 5,749,353 6,381,976 521,167 1,656,118 7,663,888 434,522 5,260,697 1,675,850 63,786 4,811,451 2,963,152 18,676,766 4,000,000 96,282 84,869 ,999,448 1,595,262 3,083,870 1,611,483 476,457 181,494 283,440 237,538 455,424 212,122 537,339 538,221 13,343,789 304,375 67,848 £220,752,916 From Colonies. £95,812,911 From British Isles. 49,711,562 8,921,510 642,528 11,423,047 9,149,076 2,983,296 2,520,863 222,940 642,102 4,934,493 4,023,819 1,310,452 27,931 1,315,345 692,430 4,282,920 3,218,946 1,554 1,099,504 910,194 887,011 670,955 207,637 37,329 75,416 127,602 323,572 87,099 403,788 338,318 122,899 60.962 £111,377,100 Exports. Total. £295,967,583 Total. 89,098,427 18,782,156 1,368,153 18,251,506 16,050,465 6,623,704 4,673,864 405,693 1,475,857 7,091,667 345,344 7,031,744 957,918 23,406 3,161,262 3,941,757 17,260,138 2,000,000 52,551 85,741 2,322,032 1,518,024 2,769,727 1,834,388 466,759 122,351 88,622 317,449 377,055 199,483 467,228 672,414 12,908,492 287,521 101,338 To Colonies. £88,303,634 £223,134,236 To British Isles. 36,984,034 8,986,897 322,527 7,683,886 7,745,415 4,081,864 1,715,391 279,660 359,708 5,158,078 35,542 6,602,193 721,190 1,164 1,852,829 508,331 3,845,362 1,052,302 1,777,376 643,971 863,290 797,194 160,903 35,771 2,557 205,032 156,730 18,753 330,997 249,794 5,120,319 9*8,468 £96,397,528 Vol. XII. (No. 81.) 130 Professor H, S. Hele Shaw [April 29, WEEKLY EVENING MEETING, T^riday, April 29, 1887. Heney Pollock, Esq. Treasurer and Vice-President, in the Chair. Professor H. S. Hele Shaw. The Boiling Contact of Bodies. When two solid bodies roll upon each other, points in the surface of one successively come into contact with corresponding points in the surface of the other in a way which differs essentially from that which occurs in sliding contact, and it is the nature of this rolling-contact that the lecturer proposed to discuss in an experimental manner. In the first place, it is well to understand clearly the nature of the relative motion of the two points which come into contact when the surfaces are such that no appreciable distortion of them takes place, and for this purpose one of the two bodies must be at rest. These may respectively be taken as the plane surface of the ground and a circular disk rolling upon it. An approximate representation of this motion is given by the end of the spokes of a wheel without its tyre. In this case it is seen that a point of the rolling body, when it is just coming into contact with the fixed surface, does so in a direction at right angles to the surface at rest, and also leaves it in the same direction. This action is very similar in kind to tbat which occurs with the continuous circle formed by the tyre. The path of a point in the rim can be drawn in a way visible to the audience by means of a piece of apparatus consisting of two circular glass plates held together by a hollow brass spindle in which slides an arm carry- in*^ a brush. The brush traces the well-known cycloid, of which the only portion now to be considered is that where it directly approaches the surface beneath. This part is perpendicular to that surface, and when epicycloids are drawn, by rolling the disk upon the arc of a circle, the same fact is brought out. One body may, however, not merely roll upon another, and a normal pressure be exerted, but they may exert a tangential force upon each other. It is convenient to keep these two cases separate ; exam^Dles of them being respectively the wheels of a railway carriage and those of the locomotive which draws it along. It is to be noted that the object in the former case is to permit one body to move relatively to another without permitting sliding contact of their sur- faces, whilst, in the latter case, in addition to this, the object is to obtain such motion. There are, however, many cases in which it is merely the motion of a body about one point which is required, such 1887.] on the Boiling Contact of Bodies. 131 as when raotiou is transmitted from the edge of one rotating disk to another, and then this distinction still more closely holds, as the normal jjressure is only obtained so as to insure the necessary tangen- tial resistance. Thus the objects of rolling motion may be classed as being — (1) To allow the relative motion of one body to another with which it is in contact without permitting relative motion of that part of their surfaces in actual contact. (2) To ohiain the relative motion of such parts of the surfaces of bodies as are not in contact by means of statical contact of the j^arts which are. The lecturer then proceeded to consider the practical proofs of the smallness of the resistance to rolling in cases where the distortion of the surfaces in contact is very small, as illustrated by the small trac- tive force required for heavy bodies properly mounted on wheels or on roller-bearings ; mentioning the case of a 12-horse-i30wer engine, the shaft of which continued to rotate for three-quarters of an hour after the motive power was withdrawn ; and another case, of a turn- table weighing 14 tons, whicih was kept in motion by a weight of SJ pounds acting upon it by means of a cord passing over a pulley. The small distortion of such surfaces when transmitting motion requiring expenditure of energy to maintain, was next made clear by giving certain facts as to the accuracy with which one surface was developed or measured out upon another. An account was given of experiments made with apparatus specially prepared by the lecturer to investigate this point. Tliis apparatus consisted of two accurately turned brass disks pro^Derly mounted upon a frame, and the relative positions of these disks could be interchanged so that any minute differences in their peripheries could be detected. The experiments, which were very difficult to carry out accurately, showed that under the best circumstances, motion with an error of only 1 in 300,000 of the distance passed over could be obtained. This accurate measuring out of the surfaces one upon another was employed in various ways for purposes of measurement, and these, by means of models and diagrams, were briefly explained. Although the foregoing facts prove that, under suitable conditions, distortion at the points of contact is very small, yet some resistance at these points always occurs, because no bodies are perfectly hard ; and the nature of this distortion and consequent resistance was next discussed. The explanation of the resistance opposed by a soft surface to a bard body rolling upon it, as first given by Prof. Osborne Eeynolds, was applied by the lecturer to account for a very remarkable effect produced in the disk, globe, and cylinder integrator of Prof. James Thomson. This effect, which was the turning of the cylinder when the sphere was rolled along it in a horizontal direction, was repro- duced by means of a large model. The action of a soft body rolling upon a hard surface was next considered, with the result of showing K 2 132 Prof. H. S. H. Shaw on the Boiling Contact of Bodies. [Apiil 29, that the same reasoning would not account for the turning of the cylinder in the same direction as before with the above model, and the lecturer then proceeded, by means of diagrams, to oifer an exj^lana- tion of this and other phenomena. The various effects obtained with bodies of different relative degrees of hardness were discussed at length, but figures would be needed to make these points clear. Finally, an explanation was given of the cause of an error which always appeared in a certain imj)ortant class of integrators caused by tlie slipj)ing of the edge of a disk over a surface on which it rolled iu circumstances under which it had apparently never been suspected that slipping did actually take place. This the lecturer had been enabled to discover and measure by means of a special piece of appa- ratus, a model of which was exhibited and the eflects shown by its means. The facts and reasoning, which were given in the lecture, all related to the rolling contact of bodies, and the lecturer ventured to think that, imperfect as the treatment of the subject had been, it was one of such importance, not merely from the point of view of the practical applications he had mentioned, but in its scientific aspect, dealing as it did from a novel point of view with the nature and pro- perties of solid bodies, as to be worthy of being thus brought before the Boyal Institution. ^^^''•J Annual Meeting. I33 ANNUAL MEETING, Monday, May 2, 1887. Sir William Bowman, Bart. LL.D. F.R.S. Manager and Vice- President, in the Chair. l«J^f' Annual Report of the Committee of Visitors for the year 1886, testifying to the continued prosperity and efficient management ot the Institution, was read and adopted. The Real and Funded Property now amounts to above 83,000Z. entirely derived from the Contributions and Donations of the Members. Forty-eight new Members paid their Admission Fees in 1886. deliverl'dfnT886."'"" ""' ""^^^^^^^ ^^^"^^^^ ^^^^— -- 9« Jj"? ^''''^^ T-^ Pamphlets presented in 1886 amounted to about 288 volumes, making, with 443 volumes (including Periodicals bound) purchased by the Managers, a total of 731 vofumes added to the Liibrary m the year. ^.Z^n^^VZ" ''n''* *° *''' P'-'^««l«"t. Treasurer, and the Honorary P?.off,t7' f 11 9om«'ittees of ITanagers and Visitors, and to the Professors, for their valuable services to the Institution durini and /S'c2e/ices— Proceedings, Vol. XXII, Part 2 8vo 1887. Vol. XII. (No. 82.) p 202 General Monthly Meeting. [Feb. 6, Antiquaries, Society o/— Proceedings, Vol. XI. No. 4. 8vo. 1887. Asiatic Society of Bengal— J onmB,], Vol. LIV. Part 2, No. 4 ; VoL LV. Part 2, No. 5; Vol. LVL Part 2, No. 1. 8vo. 1885-7. Proceedings, 1887, Nos. 6-8. 8vo. Astronomical Society, Boyal— Monthly Notices, Vol. XLVIII. Nos. 1, 2. 8vo. 1887. Ateneo Fene^o— Kevista Mensile, Serie XI. Vol. I. Nos. 1-6 ; Vol. II. Nos. 1, 2, 5, 6. 8vo. 1887. Bankers, Institute o/— Journal, Vol. VIII. Part 9 ; Vol. IX. Part 1. 8vo. 1887-8. Basel Naturforschende Gesellschaft—VerhsLndlungen, 8te Thiel, Heft 2. 8vo. 1887. Bavarian Academy o/;S'czenoes— Sitzungsberichte, 1887, Heft 2. 8vo. 1887. Birmingham Philosophical Society — Proceedings, Vol. V. Part 2. 8vo. 1886-7. British Architects, Royal Institute o/— Proceedings, 1887-8, Nos. 4, 5, 6, 7. 4to. Bureau of Education, U.S. — Circulars of Information, No. 1. 8vo. 1887. The Study of History in American Colleges and Universities. By H. B. Adams. 8vo. 1887. California, University o/— Biennial Eeport, 1886. 8vo. Register, 1886-7. 8vo. Chemical Society— Journal for Dec. 1887, Jan. 1888. 8vo. Churchill, Messrs. J. and A. (the Publishers) — Journal of Laryngology and Rhinology, No. 12. 8vo. 1887. Corfield, W. H. 31. D. and Louis C. Parhes, M.D. (the Authors) — The Treatment and Utilization of Sewage. 3rd Edition. 8vo. 1887. Coivles, Eugene H. Esq. M.R.I. — Aluminum Bronze for Heavy Guns. By A. H. Cowles. 8vo. 1887. Crisp, Frank, Esq. LL.B. F.L.S. &c. M.R.I, (the Editor)— 3 ournoX of the Royal Microscopical Society, 1887, Part 6. 8vo. The Microscope in Theory and Practice. Translated from the German of Carl Naegeli and S. Schwendener. 8vo. 1887. Dawson, Sir William, F.R.S. (the Author) — Note on Fossil Woods and other Plant Remains of W. Canada. 4to. (Trans. Roy. Soc. Canada.) 1887. Dax, Socie't^ de Borda — Bulletin, 2^ Serie, Douzieme Annee, Trimestre 4«'. 8vo. 1887. Editors — American Journal of Science for Dec. 1887 and Jan. 1888. 8vo. Analyst for Dec. 1887 and Jan. 1888. 8vo. Athenajum for Dec. 1887 and Jan. 1888. 4to. Chemical News for Dec. 1887 and Jan. 1888. 4to. Chemist and Druggist for Dec. 1887 and Jan. 1888. 8vo. Engineer for Dec. 1887 and Jan. 1888. fol. Engineering for Dec. 1887 and Jan. 1888. fol. Horological Journal for Dec. 1887 and Jan. 1888. Svo. Industries for Dec. 1887 and Jan. 1888. fol. Iron for Dec. 1887 and Jan. 1888. 4to. Murray's Magazine for Dec. 1887 and Jan. 1888. 8vo. Nature for Dec. 1887 and Jan. 1888. 4to. Revue Scientifique for Dec. 1887 and Jan. 1888. 4to. Scientific News for Dec. 1887 and Jan. 1888. 4to. Telegraphic Journal for Dec. 1887 and Jan. 1888. 8vo. Zoophilist for Dec. 1887 and Jan. 1888. 4to. Florence, Biblioteca Nazionale Centrale — Bolletino, Num. 47-49. Svo. 1887. Codici Palatini, Vol. I. Ease. 6. 8vo. 1887. Franklin Institute— J onrnal, Nos. 744, 745. Svo. 1887. Freshfield, Edwin, Esq. LL.D. F.S.A. M.R.I, (the Editor)— The Vestry Minute- Book of the Parish of St. Margaret Lothbury, 1571-1677. 4to. 1887. (Privately Printed). Geographical Society, Royal — Proceedings, New Series, Vol. IX. No. 12 ; Vol. X. No. 1. Svo. 1887-8. Geological Society — Quarterly Journal, No. 172. Svo. 1887. 1888.] General Monthly Meeting. 203 Geological Society of Ireland, Royal— J oumal, Vol. XVIII. Part 2. 8vo. 1887. Gordon, Surgeon- General C. A. M.D. G.B. M.R.I, (the Author) — Comments upon Keport of Committee on Babies and Hydrophobia. 8vo. 1888. Harlem, Societe HoUandaise des Sciences — Archives Neerlandaises, Tome XXII. Liv. 2, 3. 8vo. 1887. Verhandelinsjen, 3^^^ yerz, Deel V. P^e gtuk. 4to. 1887. Historical Society, Royal — The Teaching of History in Schools. By Oscar Browning. 8vo. 1887. Holmes-Forbes, A. W. Esq. M.A. M.R.I, (the ^wf^or)— Practical Essay Writing. 12mo. 1887. Iron and Steel Institute — Journal, 1887, No. 2. 8vo. Johns Hopkins University — American Journal of Philology, Vol. VIII. No. 3. 8vo. 1887. American Chemical Journal, Vol. IX. No. 6; Vol. X. No. 1. 8vo. 1887-8. Studies in Historical and Political Science, Fifth Series, Nos. 10, 11. 8vo. 1887. University Circular, Nos. 60, 61, 62. 4to. 1887. Keio Observatory— Report for 1887. 8vo. 1887. Linnean Society— J omual, Nos. 118, 136, 152-4, 160, 161. 8vo. 1887. Manchester Geological Society — Transactions, Vol. XIX. Parts 11, 12. 8vo. 1887. Mechanical Engineers' Institution — Proceedings, 1887, Nos. 3, 4. 8vo. Library Catalogue and Index of Proceedings, 1847-87. 8vo. 1887. Meteorological Office— Weekly Weather Keports, Vol. IV. Nos. 34-45. 4to. 1887. Meteorological Society, Royal — Quarterly Journal, No. 64. 8vo. 1887. Middlesex Hospital — Keports for 1886. 8vo, 1 887. Ministry of Public Works, Rome — Giornale del Genio Civile, Serie Quinta, Vol. I. No. 11. 8vo. AndDisegni. fol. 1887. New South Wales Royal Society — Journal and Proceedings, Vol. XX. 1886. 8vo. 1887. Neiv York Academy of Sciences — Transactions, Vol. IV. 8vo. 1884-5. North of England Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVII. Part 1. 8vo. 1887. Numisnudic Society — Chronicle and Journal, 1887, Part 3. 8vo. 1887. Odontological Society of Great Britain — Transactions, Vol. XX. Nos. 1, 2, 3. New Series. 8vo. 1887. Perigal, Frederick, Esq. (the Author) — Some Account of the Perigal Family. 8vo. 1887. Pharmaceutical Society of Great Britain — Journal, Dec. 1887, Jan. 1888. 8vo. Photographic Society — Journal, Vol. XII. No. 2. 8vo. 1887. Rio de Janeiro Observatory — Revista, Nos. 11, 12. 8vo. 1887. Royal Society of London — Proceedings, Nos. 259, 260. 8vo. 1887. Philosophical Transactions, Vol. CLXXVII. Part 2. 4to. 1887. Sanitary Institute of Great Britain — Transactions, Vol. VIII. 8vo. 1887. Saxon Society of Sciences, Royal — Philologisch- historische Classe: Abhandlun- gen, Band X. No. 7. 8vo. 1887. Mathematisch-physische Classe : Abhandlungen, Band XIV. Nos. 5, 6. 8vo. 1887. Seismological Society of Japan — Transactions, Vol. XI. 8vo. 1887. Society of ^Ws— Journal, Dec. 1887, Jan. 1888. 8vo. St. Petersbourg Academic Imp^riale des Sciences — Memoires, Tome XXXV. Nos. 4-7. 4to. 1887. Telegraph Engineers, Society o/— Journal, No. 68. 8vo. 1887. Thurston, Edgar, Esq. (the Author) — Marine Fauna of Rameswaram (Madras). 8vo. 1887. Vereins zur Beforderung des Gewerbfleises in Preussen — Verhandluugen, 1887: Heft 9, 10. 4to. Victoria Institute — Journal of Transactions, No. 83. 8vo, 1887. Wild, Br. H. (the Director) — Annalen der Physikalischeii Central-Observatoriums, 1886, Theil I. 4to. 1887. Repertorium fur Meteovologie, Band X. 4to. 1887. Supp. V. and Atlas. 1887. p 2 204 Mr. William Henry Preece [Feb. 10, WEEKLY EVENING MEETING, Friday, February 10, 1888. His Grace the Duke of Noethumberland, K.G. D.C.L. LL.D. President, in tbe Chair. William Henry Preece, Esq. F.K.S. MM.I. Safety Lamps in Collieries. On a fine summer's day the sun expends an average of one horse- power on every 30 square feet of the earth's surface in this latitude, or 1450 horse-power per acre. This great gift of energy is neither utilised nor stored by man at present, though Nature presents us with some of it in waterfalls and flowing streams. The sun itself has been more generous. Ages upon ages ago it shone with resplen- dent glory on a grand luxuriant flora of a uniform but flowerless character in a climate warm and damp. England formed part of a tropical jungle or swamp, where grasses, mosses, ferns, and sedges, coniferse, araucaride, equisetaccse, sigillarise grew and flourished, perished and fell in situ, to be covered up by the following geological forma- tions and compressed into those grand seams of coal that form now the principal source of England's greatness and wealth. If language be fossil poetry and words condensed history, then coal may be derived from coelum or kolXo^ (Jcoilos), and imply a Heaven-sent gift. The first authentic account of coal digging dates from the reign of Henry III., when Newcastle sent its first cargoes by sea to London, and thus gave the mineral the name of sea-coal. Early records of the output of coal are wanting. In 1700 it was 2,614,000 tons. In 1800 it was 10,000,000 tons. In 1850 it reached 42,000,000 tons. In 1886 it reached 157,518,482 tons. A ton of coal occupies very nearly a cubic yard of space. Hence this quantity of coal, if placed in Hyde Park, would form a mountain as high as Snowdon, and if erected as a wall around the coast-line of Great Britain, it would be 6 ft. wide and 30 ft. high. It would form a girdle round the world 3 ft. wide and 12 ft. high. We extract from the earth twenty times more energy than the sun can possibly restore to it by the growth of forest, and we are gradually but surely tending towards the time when this store of power, heat, and light, will be exhausted, when our busy hives of industry must seek other shores, and when England will perhaps become a summer resort for a wealthy Anglo-Saxon race occupying other quarters of the globe. 1888.] on Safety Lamps in Collieries, 205 Coal is not only, like knowledge, power, but, like the precious metals, it is wealth. The average price of coal at the pit's mouth in 1886 was 5s. per ton, and thus its total value was 40,000,000?., but when we consider the average price paid for it, we must double, if not treble, this lump sum. The number of collieries open was about 3500, and since it costs 100,000Z. to open a colliery 2000 ft. deep, when we think of the railways, the canals, the ships, the shops, the marts employed for its transit and its distribution, we can only con- clude that the capital embarked in this industry must equal, if not exceed, the National Debt. The hewing and raising of coal is unquestionably a dangerous occupation. " The price of coal is pit-men's lives," said an old collier to George Stephenson. 520,000 persons are employed in our col- lieries, and the output per person is 308 tons. 953 persons met their deaths in 1886 ; but it is satisfactory to know that a miner's life is more than twice as safe now as it was thirty years ago. The number of persons employed per death was — In 1856 242 In 1886 545 The number of tons raised per life lost was — In 1856 64,700 In 1886 188,800 Most people, if asked what was thfe principal cause of this loss of nearly 1000 lives, would answer explosion of fire-damp, but this would not be true. The principal cause of accident is falls of roof and sides. In 1886 there were from — Falls of roof and sides .. Explosions Trams and tubs Miscellaneous .. Thus falls of roof form 41 per cent, of the whole, and explosions 23 per cent. Explosions attract immense attention, from their publicity and their appalling suddenness and magnitude. It is dreadful to take up a morning paper and read of 268 fellow creatures engulfed, as at Abercarne in 1878, or 164 at Seaham in 1880 ; but the daily and steady loss of life by ones and by twos fails to get chronicled, and passes unheeded by with the very great majority of the 20,000 violent deaths that occur in these islands every year. In order that you may see how coal is won, and hewed, and raised, how dangers are incurred and surmounted, I will take you into a coal- mine—one of the Cannock Chase collieries of Staffordshire — by aid of a beautiful series of photographs, taken by means of magnesium light by my friend, Mr. Arthur Sop with, the eminent manager of those mines. 461 deaths 129 ?» 81 »j 282 jj 206 Mr. William Henry Preece [Feb. 10, 1. We commence with a map of Great Britain, showing in shaded lines the distribution of the various coal-fields. 2. A view on the surface of the pit's mouth, showing the engine- house, the pulleys, frames and ropes, with their motion up and down their respective shafts, the banking shed for tipping the raised coal into railway waggons and carts, the waggons laden with coal, the trucks laden with wood for "cogging," and timber for treeing, supporting, and strengthening. This particular pit raises about 1000 tons in eight hours, and it employs from 500 to 600 men. 3. This is the top of the shaft, with the cage in position ready to descend with an empty tub. Every pit has two shafts, the up-cast and the down-cast, for working and ventilation. They vary from 10 feet to 20 feet in diameter. This particular pit is 360 feet deep, but there are several in England over 2000 feet. The rate of descent is 18 feet per second, or about 20 miles an hour. 4. This is the bottom of the shaft ; the tub, laden with coal, just brouf^ht from the w^orking face, the man in the act of running it on to the cage, and his hand in the act of signalling to the surface. 5. An overman's cabin hewn out of the coal, the underviewer making his report of the condition of the mine after his morning inspection. 6. The engine-plane or level, which is 2000 yards long. A hewer, pike in hand, meets the underviewer with his " Clanny," and learns the state of the mine. The truck is worked by an endless TO-pe, it has a double way, the laden tubs drawn towards the shaft, and the empty tubs towards the workings. It will be seen that the roof is strengthened by iron bars instead of the timbers generally used. 7. Clipping a tube to the rope by means of a shackle and coupling. The ordinary cross timbers or bars are here shown sup- porting the roof. 8. A level branch off the engine-plane. Horses or ponies now take up the work and draw the empty tub through a " gob " road — a road through the whole working — to the working face or long wall. Though a horse in the pit does scarcely one-half of the work of a horse on the surface, it lives as long. There are horses that have never seen daylight for 16 years. 9. A road near the face ; men resting from their work — taking their lunch or "jack bit." 10. The end of the road, the tub taken off the rails and dragged to the face. 11 and 12. The working face. Undercutting ; taking away the hard under-clay preparatory to blowing or wedging down the super- incumbent coal. 13. Punching a hole for blasting with powder. The mode of supporting a "gob" road by cogging is very well shown in this slide. 14. A way end, showing the result of a blast. 1888.J on Safety Lamps in Collieries. 207 15. "Bannocking" or holing the top; the reverse to under- cutting, the charge being put in at the bottom and the explosion acting upwards. 16. Drilling a hole for a lime cartridge. The anomaly of using gunpowder and safety lamps in the same place is destroyed by the use of caustic lime, which forces out the coal by the expansive action of water on the lime. 17. The act of watering the lime by pumping. 18. The result, the fallen coal. 19. Buildicg a cog-wall — a strong boundary to the "goaf" or gob, which consists of the refuse of the old working and the subsident roof. 20. Eock " ripping," clearing a roof which has subsided and re- ducing the height of the way, so as to leave room for the horses to go through the old working. This is the most dangerous operation connected with coal mining. 21. Setting trees or upright timbers to support the roof. Each tree or stanchion has a cap or lid, and they are placed 6 feet apart. 22. Drawing timber by means of a chain for use again, so as to allow the roof to fall or subside uniformly, and not to break up in pieces. 23. Examining a waste for gas. This is done two or three times a day by special firemen with the ordinary safety lamp. 24. Tapping old working for wafer ; a source of great trouble in collieries. 25. Trying the roof. 26. A surveying party. A fault in the seam is shown in this slide. 27. The furnace used for ventilation. This has now been abandoned for more perfect and less wasteful mechanical contri- vances. I have shown you most of the operations connected with the win- ning and working of coal ; some of the risks the miner incurs ; some of the troubles arising from gas, water, and falling roofs ; and one of the modes of producing ventilation — the chief prevention of accident. "What our mines could have been in days gone by it is impossible to conceive ; now mechanical appliances are so admirable that many mines are as perfectly ventilated as our homes. The temperature below ground is so uniform — 50° F. at 50 feet, and rising 1° for each 55 feet — the formations are so dry that I have actually heard it pro- posed to establish a sanatorium for consumptive patients underground, lighted by electricity, and suj^plied with every luxury. All mines are required to have two shafts — one the intake or down- cast, the other the return or up-cast, and the workings are so inter- laced with ways and roads, doors are inserted here and there to direct the current, anemometers are used to measure its rate of flow, that any ordinary inroad of gas is swiftly swept away. Fire-damp, or pit 208 Mr. William Henry Preece [Feb. 10, gas, is marsh gas (C H4). It oozes out gently from the exposed seam, or sometimes it bursts out through some fissure with great force, forming what are called " blowers." If it be mixed with air, in the propor- tion of from 5 to 9 per cent, of gas, it becomes highly explosive, and is the prime cause of those fearful disasters that have made coal mining so terrible. In gasless mines candles always have been and still are used, but in early days, in foul places, men had frequently to work in the dark, or to be content with the feeble illumination of the phosphorescence of decaying fish. It is remarkable how the eye adapts itself to feeble light, and in the Cimmerian darkness of a coal-mine even phospho- rescence has a useful illuminating effect. In many places they used the steel mill, a disc of steel rotated rapidly against flint, giving light by the shower of sparks thrown down. It is most remarkable that no scientific thought was devoted to this subject until 1815. In 1813 Dr. Clanny, of Newcastle, had devised a very poor lamp, the air to support which was driven by bellows through water ; but in 1815 Sir Humphry Davy devoted his powerful mind and skilful hands to solve the question, and speedily invented in this very Institution his immortal safety lamp. It is a remarkable coincidence that in the same month another powerful but untutored mind, by strong observant pow'crs and pure mechanical reasoning, had arrived at very nearly the same result ; and even to this day the affectionate remembrance and name of the eminent Northumbrian brakesman, George Stephenson, is maintained by the use of the " Geordie," in his old home, the Kil- lingworth Colliery. Davy's classical paper was read before the Royal Society, on November 11, 1815, and was entitled " On the Fire Damp of Coal Mines; and on Methods of Lighting the Mine so as to Prevent Explosion." He showed that flame would not pass through small tubes and apertures, and how in comparatively still air, however charged with gas, a wire gauze surrounding the flame so reduced the temperature by radiation that explosion was impossible. Ingress of air and egress of products of combustion are resisted. He showed that a flame so protected gave immediate intimation of the presence of gas by burning dimly, and by becoming capped with a blue flame, or aureole, that though the wire gauze became redhot, it still radiated away the heat sufiiciently to prevent its reaching the temperature point of explosioD. He also pointed out, which has been strangely neglected, until enforced recently by the Eoyal Commissioners on Accidents in Mines, that it failed to act in a current of air, but that this effect of currents could be diminished by shielding or protecting the inlet of air. The main principle discovered by Davy is the basis of all safety lamps burning oil or spirit, but several departures in form have been proposed at different times. The '* Geordie " is in reality a Davy lamp with a glass shield. The " Jack " lamp is a Davy in a tin can. The " Clanny " is a Davy lamji with the flame portion surrounded 1888.] 071 Safety Lamps in Collieries. 209 by a thick glass cylinder to increase the emission of light, and now with a bonnet or shield to protect it from currents of air. The " Mueseler," or Belgian type, is a " Clanny " with a central metallic cone acting as a funnel to increase the draught, and therefore the light. The " Marsaut," or the French type, is a bonneted or pro- tected " Clanny," with two and three gauzes added to increase the security. The number of lamps is legion. A new intake here, a fresh egress there, a new direction to the currents of air feeding the flame, a change in the form or character of the wick, a lock, a different form of pricker, a shut-off or extinguisher (automatic or manual), is quite sufficient to justify a new patent and a new name. The Eoyal Commission experimented upon 250 different kinds of lamps. Since the commencement of the year a new Act has come into force rendering it unlawful to use the plain " Davy," " Stephenson," or " Clanny " lamp in mines where safety lamps are necessary. They must be shielded, and great numbers are being converted into bonneted " Marsauts " and " Mueselers." They are also being con- structed to burn the best vegetable oil (rape or colza), to which one- third mineral oil is added, as recommended by the Eoyal Commission, to enhance the light-giving power of the lamp. These converted lamps have baffled all attempts to explode them in currents of explosive gases of very high velocity, and under the most rigid tests. There are several objections to these oil lamps. They go out, or are put out when danger exists ; they render that most important and essential duty, examination of the roof, difficult and insufficient. If they become extinguished by accident or design, much time is necessarily wasted in getting them relighted, an operation that must be done at or near the shaft, perhaps two miles away from the work- ing face, and which therefore reduces the output of coal and the earnings of the collier. The light they give, even at the best, is very small — about one-third to half of a candle. There are several dangers present. The Eoyal Commission said : — " The source of light within the lamp should be unable under any circumstance, at all likely to occur in working coal to cause the ignition of an inflammable mixture of fire-damp and air, even when this is passing at a high velocity." But glasses break by water, heat, falling coal, and accident. Joints get loose and bad even when protected by asbestos washers. They prove a constant temptation to the thoughtless and callous to get a light. The perfect light does not exist at present, but while these mechanical lamps are very excellent in their way, electricity seems likely to step in and supply their deficiencies and fill a decided want. An electric lamp can be made to give any desired amount of light, but anything between half a candle and a candle seems easily attainable, and such a light can be maintained steady and bright in explosive gases and in strong currents of air. They are simple in construction, easy of inspection ; they are not likely 210 Mr. William Henry Preece [Feb. 10, to be extinguished in handling like the Mueseler ; but they do not act as detector of the presence of gas, and they might explode gas if their protecting glass shield were accidentally broken. It is remarkable that Davy himself in 1815 experimented with an arc lamp in a closed vessel of glass, but it was not until 1865 that a practical lamp was proposed for collieries. Dumas and Benoit used a small Geissler tube illuminated by sparks from an induction coil and excited by a primary battery ; but it was heavy — it was a kind of knaj^sack to be carried on the back, and it met with no success. Mr. Swan has been more successful. The great success of the glow lamp, in the introduction of which he has played so prominent a part, and the perfection of the secondary battery have enabled him to produce a lamp that compares in weight and size and light with the best mechanical lamp. Eight hundred of these lamps are in constant use in the National Colliery in the Ehondda Valley in South Wales, and 1600 more are on order for the Kisca and Aber- carne Collieries belonging to Messrs. Watts, Ward, and Co. They are giving great satisfaction. A collier told me that the electric light was " as good as the moon." The lamp batteries are charged a great number at a time in blocks at the pit bank. Mr. Pitkin has also been very successful in making light portable lamps, and they have been practically used in Cannock Chase and at the Tyldesley Collieries in Lancashire. The " Sun " lamp is another very promising form, worked by secondary battery. It is light — 3 lb. 12 oz. ; it gives IJ candle, and this is maintained for ten hours. Secondary cells usually require about twelve hours' charge to emit a ten hour discharge, but this cell will give a ten-hour discharge with four hours' charge. It is fitted with a safety appliance — a plan patented by Mr. Senuett in 1882 — by which the lamp is automatically switched out the instant that the outer protecting glass is broken or cracked, so that contact between the hot filament of the lamp and the explosive gas is prevented. This safety appliance has been tested by Mr. Hhodes at the Aldwarcke Colliery in actual explosive mixtures. Many efi"orts have been made to introduce primary batteries for the same purpose, but up to the present moment I have seen only one — the Schanschieff — which, in efiiciency, lightness, and economy comes up to the requirements of a safety lamp. A primary has this advantage over a secondary battery — that it is charged at once by an operation as simple as that of trimming a Davy. To trim a Davy means thorough cleaning, inserting a fresh wick, pouring in new oil. A primary battery means pouring out old, and pouring in fresh solution. Occasionally zincs require renewal, but all these operations are within the intelligence of the collier, and the lamps need not go to the surface. The simplicity of the operation has distinct merits of its own that compensate for the extra cost of the materials used. The chief charm of the electric lamp is not the greater light that 1888.] on Safety Lamjps in Collieries. 211 it gives, but tlie power it gives the viewer to examine the roofs of the ways and workings ; it is so extremely portable and handy ; it can be put anywhere ; the battery can be placed on the ground or suspended by a spike to a tree, and the lamp can be fixed in the cap or around the waist ; it can be put anywhere and used anyhow. Mr. Sopwith, at Cannock Chase, has been taking heavy batteries to the working face, and using bright 5-candle lamps in reflectors, so as to illuminate the working face with a light which in that region is comparable to daylight. The men are charmed with it. The chief defects of the electric lamps are their fragility, the liability of the carbon filament to break, the weight of the battery, and the absence of gas detection ; and these defects have been very- much enhanced by imperfect construction and injudicious details. Electricians have not spent sufiicient time in the lower regions, and practical colliers have no time to go to the laboratory. When the two professions are properly amalgamated we shall very likely obtain the true safety lamp. The electric lamp is not a fire-damp detector, but an electrical appliance for this purpose is easily added. Liveing and Swan have done this ; but it is doubtful whether a more efficient detector than the Davy exists, and whether an apparatus that is so thoroughly under- stood, and so thoroughly practical, will be superseded for a purpose for which it seems so eminently adapted. I cannot conclude, especially in this place, with more pregnant words than Davy's own : — " The grafification of the love of knowledge is delightful to every refined mind; but a much higher motive is offered in indulging in it when that knowledge is felt to bo practical power, and when that power may be apj)lied to lessen the miseries or increase the comforts of our fellow creatures." [W. H. P.] 212 Sir Henry Doulton [Feb. 17, WEEKLY EVENING MEETING, Friday, February 17, 1888. William Huggins, Esq. D.C.L. LL.D. F.E.S. Vice-President, in the Chair. Sir Henby Doulton, M.B.I. Some Developments of English Pottery during the last fifty years. The opportunity for the efforts of the potters of each succeeding age lies in the fact that the manufacture is based on conditions which arc constantly varying, and sometimes even startling in their unexpected results. The material with which the potter deals is as varied as are the localities from whence it is taken, and as infinitely diversified as are the workers' tastes and ingenuity. And further, the final and essential process, the subjection to fire, " which tries every man's work of what sort it is," and especially tries the potter's work, is hidden from view, and under this condition the last stages of the work may be heightened in effect or hopelessly marred. The progress of the art of pottery affords many striking instances of the laws of growth, perfection, and decay. As schools of philosophy, poetry, and painting are subject to rise, culmination, decline and fall, so is the potter's art. It is, however, a striking fact, that, with hardly any exception, only those potters have been able to maintain a long-lived career who have relied for their staple manufacture on utilitarian rather than decorative wares. A proportion of the useful seems to be an essential condition of any degree of permanence. A school of artistic pottery is short-lived, firstly, because it is dependent upon individual taste and culture, and, secondly, because it is not remunerative. Wedgwood, Worcester, and Minton have undoubtedly maintained their continuous production through so long a period by careful attention to the requirements of domestic as well as ornamental pottery. I propose, in the limited time at my disposal this evening, to indicate the progress of the last fifty years in both useful and artistic pottery, and the happy blending of both qualities in some directions. Professor Church, in his masterly work on English pottery, says, " About the year 1790, the careful, elegant, and rich wares which had held their own for nearly half a century, were gradually displaced by more gorgeous productions, covered with gilding, and possessing even less freedom and spontaneity than the works of Chelsea and Etruria, 1888.] on Some Developments of English Pottery. 213 in fact, vulgar when not merely feeble." The decadence which then set in continued until the commencement of the new renaissance with the reign of Her Majesty. From its purity and durability, pottery, embracing the finest porcelain and the roughest earthenware, has been a useful adjunct — I might almost say an absolute necessity — for the sanitarian, the chemist, the architect, the agriculturist, and the electrician. The rapid advance of chemical and other scientific discoveries, and the application to manufactures of scientific processes, has also led to a vastly increased demand for pottery suited to such operations ; while the gigantic development of telephone and telegraph has had its proportionate effect on pottery production. The impetus given to metallurgy has brought about a greatly extended use of crucibles, and the rapid advance of sanitary science has given a distinct impulse to pottery manufacture. Indeed, pottery has in no small degree conduced to the satisfactory solution of the great sanitary problems of the present age. The application of terra-cotta, too, has led to the most successful results. The same advances in scientific research which have multiplied the demand for pottery wares have had an equal influence in improving their quality and efficiency, as well as reducing the cost of their production. In 1846, anticipating an extensive use of stoneware for street and house drainage, I began a special factory for its production, and since that time the manufacture has increafeed till it may now be considered a great national industry. The introduction of baths, sinks, lavatories, glazed bricks, ventilat- ing and syphon traps, irrigation pipes, and many other inventions have in late years provided the means of greatly reducing the death- rate of large communities, and it is not too much to say that sanitary science has advanced pari passu with the use of pottery. The increasing demand for chemical vessels of stoneware capable of resisting acids may be regarded as giving the first important impulse to the Lambeth Potteries. At the present time, care and experience, to- gether with better machinery for the preparation of the material, makes it practicable to produce vessels of four or five hundred gallons capacity. Under the category of things both useful and beautiful in pottery, are earthenware tiles. In 1840, E. Pressor, of Birmingham, obtained a patent for the manufacture of buttons by reducing the material of porcelain to a dry powder, and subjecting it to strong pressure between steel dies. Pressor disposed of part of his interest in this patent to Minton, who then made some very beautiful buttons and studs. In 1841 Blashfield conceived that this process might be extended to the manufacture of small tiles and tesserae. In 1843, the process of manufacture was exhibited by Pressor and Blashfield at a meeting of the Royal Society, when the late Prince Consort took great interest in the making of tesseras, and desired an account of the whole subject to be sent him. 214 Sir Henry Doulton [Feb. 17, To those best able to appreciate the obstacles to be overcome, the results achieved in this direction by Minton, and later on by Maw, stand out as triumphs of patient technical research. I cannot here refrain from rendering my tribute of admiration to the beautiful lustre pottery of De Morgan, which has had its principal application to tiles. Of all the adaptations of Persian and Hispano- Moresque art, liis has been the most successful. Maw & Co. have, however, lately almost rivalled in their ordinary productions the exquisite work of this school. Nor must we fail to notice the constructive faience or glazed terra- cotta so successfully produced during the last few years by Messrs. Minton, Wilcock, Cliff, and Doult(»n, which has lately become a recognised method of embellishment for many of our large hotels. Of late years the gradual introduction of fireclay into open fire- places in the shape of slabs for back and sides has directed attention to the desirability of its introduction in England in the form of closed stoves. Decorative Pottery, — Looking back over the last half-century, it is apparent that progress rather than discovery has marked the age so far as pottery is concerned. The IStli century is filled with the names of pioneers in the potter's art in this country, whose patient research has enabled their followers to improve and perfect the results. But it is difficult to recall during the Victorian age many discoverers in plastic manufacture which can be named on the same lines as those of Elers and Ashbury, who introduced ground flint ; Sadler of Liverpool, and Dr. Watt of Worcester, who introduced pottery printing ; Cooksworthy, kaolin ; and Wedgwood, jasper ware ; and other important discoverers. The introduction of lead-glaze and of the process of transfer- printing had completely displaced the demand for salt-glazed stone- ware, which virtually ceased at the end of the last century. The discovery by Joseph Spode of opaque china was followed by the perfecting of parian. This success was greatly due to Copeland, but there is little doubt that Minton's experiments in the same direc- tion were simultaneous. During the past fifty years there has been continuous development of Messrs. Minton's productions, and their name, together with those of Worcester and Wedgwood, occupy a position of honour among potters in later times. The masterly executions of Bolt in enamel painting on dark-blue, or " Limoges Worcester," together with the later introduction by Mr. Binns of ivory porcelain at the Eoyal Porcelain Works, are achievements of which the present era may justly feel proud. Salt-glazed Stoneware. — In examining the various English wares of early date, stoneware arrests attention as a great advance on all that has gone before. That advance was due, not so much to any patient insight into quality or admixture of material, as to a distinctly novel principle of manufacture, viz. the glazing of ware by vaporous flux while approaching the vitrifying point, common salt being thrown 1888.] on Some Developments of English Pottery. 215 into the kiln when at full white heat. The decomposed fames of soda combine with the minute particles of silica in the surface of the ware, and form a thin glassy coating of intense hardness. Experience soon showed the discoverers that the full qualities of the glazing by this method could not be reached except as the ware approached the vitri- fying point, so that those means adopted to give brilliancy to the glaze also of necessity produced excellence of body and strength and durability. Though talented decorators were certainly employed on Delft ware in Lambeth at the early part of the present century, no attempt was made to apply this talent and experience to the embellishment of the salt-glazed ware, which was allowed to sink into a manufacture devoid of all pretence to beauty. Such was the condition of the stoneware manufacture at this time, and such it continued until 1867, when the first efforts were made at Lambeth. It is somewhat remarkable that the latest introduction of the last half century should consist of an art-ware which, instead of gathering up all the resources and experience of the past, sprang, as it were, from an altogether independent stock, and though in some respects apparently a revival of old traditions, and rising up from the selfsame spot as the Delft potteries, the Doulton stoneware received no inspira- tion from its predecessors. It has been successful in starting out a path for itself both original and progressive. In 1868 the idea was conceived of attempting to raise salt-glazed stoneware into an art material. The 'first attempts at decoration were confined to form and relief with simple coloured bands and runners. To this, " sgraffito " or incised outline filled in with blue, was soon added. A small collection of vases and jugs was exhibited at the International Exhibition of Paris, 1867, and from this time till 1871 no further progress was made. Early in 1871 it was determined to make every effort at Lambeth Pottery to originate examples of decorated stoneware. The result distinctly aimed at was successfully attained, and the greater portion were eagerly purchased for the museums throughout Europe. It is satisfactory to know that the strenuous efforts made during the last fifteen years to maintain the unique and original characteristics of the ware have been appre- ciated. The later months of 1873 also brought about the introduction of an entirely new branch of works, viz. Lambeth Faience, a ware painted under the glaze on a soft biscuit of warm tone and glazed with a lead glaze. Each International Exhibition called forth renewed effort, and that of Paris in 1878 was still more varied and important. In the following year another new ware was introduced called " Impasto," the decoration being executed on the soft clay by means of coloured slips. In the year 1880 the so-called " Silicon " ware was introduced. It consists of a vitrified stoneware impregnated with metallic oxides throughout its mass and coated with a " smear " or semi-glaze. 216 Sir H. Doulton on Developnents of English Pottery. [Feb. 17, It is mnch to be feared that the taste and intelligence of purcbasers has not advanced concurrently with the production of really beautiful and artistic works. There is with the public of the present time a morbid craving after novelties, irrespective of their intrinsic excel- lence, and this craving leaves neither designer nor manufacturer time to develop the full capabilities of his productions before the passing day of public appreciation has gone by. I might here refer to two original workers whose early training was accomplished at the Lambeth School of Art, viz. Miss Barlow and Mr. Tin worth. Mr. Tin worth undoubtedly owes the recognition and early development of his powers to this School, and opportunities of more advanced study to the Royal Academy. (Lantern views were here shown of some of Mr. Tinworth's works.) The last fifty years has seen development rather than initiative in pottery treatments, and science even more, than art will probably have the greatest influence on this manufacture in the immediate future. I would fain indulge the hope that a large proportion of the works of this period, surviving the ravages of time, will testify in the distant future to the combined beauty and utility of the production of the English potter in the Victorian age. [H. D.] (The lecture was illustrated by a series of specimens, and in the library was exhibited a collection of the productions of Doulton, Minton, Worcester, Maw, and De Morgan, including some examples of Messrs. Doulton's Burslem ware.) 1888.] The Very Bev. G. G. Bradley on Westminster Abbey. 217 WEEKLY EVENING MEETING, Friday, February 24, 1888. Edwaed Woods, Esq. M. Inst. C,E. Vice-President, in the Chair. The Very Rev. G. Granville Bradley, D.D. Dean of Westminster. Westminster Abbey. The lecturer, who spoke merely from a few notes, began by dwell- ing almost in despair on the extraordinary range and multifarious aspects of his subject. He gave a sketch of three or four lines of thought to which he or others speaking on such a subject might have confined themselves. He might have found a rich field of interest in tracing the history of the mere fabric, from the day when the Norman builders of Edward the Confessor reared the structure which covered nearly or quite the same ground as that on which its more stately successor stands to-day. He might, avoiding technical and architectural details, have described the work of Henry III., and its slow and gradual completion, till ^t last, after five centuries of active work and of long pauses, its western towers stood up new and glistening in Hogarth's picture of St. James's Park now on view. Or he, or one more competent, might have called their attention to the Abbey as a museum of priceless value, from the merely artistic side of its contents, including as they do a continuous series of English and foreign sculpture from the thirteenth century down to yesterday. Or, again, he might have tried to put before them some- thing of the inner life and outward history of the great Benedictine monastery of which this historic church formed but a part. How few of the thousands of visitors to the Abbey thought of the genera- tions of monks who for 500 years paced those cloisters, slept in that dormitory, and sang and knelt in that choir, whose abbots were the treasurers, or counsellors, or secretaries, or ambassadors, or gaolers of kings, whose domains and manors comprised Hyde Park and St. James's, much or all of Kensington Gardens, and such districts as Chelsea, Paddington, Belgravia, and Covent Garden. Or, fourthly, he might have put before them, by the aid of photography, illustra- tions of the tombs, and spoken of the historic memories which they awake, alike in themselves and in their often touching juxtaposition. But he would turn from these and other inviting vistas of thought, and content himself with putting before them a few hints as to the various influences whose combined action had given the Abbey such a hold on the affections of all who speak our language, and which Vol. XII. (No. 82.) q 218 Tie Yerij Bev. G. Granville Bradley [Feb. 24, gave a hundred-fold force in the present day to the striking words of Edward IV., who in a letter to the Pope, written over four cen- turies ago, spoke of it as dear to the orhis Anglicanus — the " whole English world." What were then, what are now, the claims to so unique a position of a church whose legal title is " the Collegiate Church of St. Peter, Westminster " f (1) It was no doubt a great monastic church, as its very name of Ahhey imj)lied. Its very legends, such as that of the consecration of the first rude church by St. Peter himself, were closely intertwined with its real history, and had aided its abbots in their pertinacious and successful efforts to assert their entire independence of the English Episcopate. But had this been all, its interest might have grown pale when its days as an abbey church came to an end under Henry VIII., when for a short time it became what Shakespeare calls it — a " Cathedral Church " — and reappeared with its present constitution. It owed its singular position to excep- tional causes. For (2) it was the great monument raised by the last of the English Kings who were heirs of Alfred ; it was reared by Edward the Confessor as his own burial-place. And as such the new and foreign dynasty of the Conqueror claimed a share in it as his heirs, assumed their crowns one after another by his graveside, till at last the fusion between Norman and Englishman was marked by the erection of the most important part of the new church by Henry III., who chose his own place of sepulture by the side of the Shrine in which he placed the body of the sainted King. Round that shrine, with some interesting exceptions, slept his sons and successors, and it became more and more what Edward III. expressly calls it, the colossal " Eoyal Chapel " of the Kings of England, and its history became in every generation more and more intertwined with the history of England as shadowed forth in those Kings — in their accessions, their marriages, their wars, and their deaths. (3) To the people of England also it had become dear — first, as contain- ing the relics of the native King to whose reign they looked back as the golden age of the liberties of England ; and later on as the scene not only of great religious ceremonies, but of great pageants held in memory of national triumphs. There, too, in its splendid Chapter- house was the meeting place of the Commons of England, of the Parliament that was to become the mother of Parliaments. And (4) from the awakening time of the Reformation its influence grew and widened. There was not merely the splendid addition made to it on the very eve of that epoch by the chapel of Henry VII., but there was the recognition of other forms of greatness than that of kings and warriors and statesmen and abbots and ecclesiastics, that dated from the erection of the monument to Chaucer and the burial of Spenser. The tide of interest spread and deepened with every generation, till its crowd of monuments touched the memories and affections of Englishmen, Scotsmen, Welsh, and Irish — alike of citizens of the American Republic, of members of our own colonial 1888.] Gil Westminster Ahheij. 219 empire, and of natives of India — alike of Churchmen and of Noncon- formists, The very "jumble and chaos" of monuments of which visitors sometimes spoke had its interest. In the nave, in which all was comparatively modern, Pitt, with outstretched arm, looked over a Jacobite Dean's grave on his right, and his rival Fox's monument on his left. Before him were the gravestones of an Irish Archbishop and a Nonconformist missionary, of sailors, soldiers, engineers, and architects, of Newton, and of Darwin. Far to the east lay in the same vault the first of our Welsh and the first of our Scottish Kings. By a fortuitous juxtaposition Darnley's effigy knelt with its face fixed on the tomb of his wife, Mary Queen of Scots. Behind him knelt his brother, gazing with folded hands on the vault that holds the ashes of his daughter Arabella Stuart. So again, by an ill-considered removal, the tablet of Major Creed, who fell at Blenheim, had been taken from the spot where his mother had placed it, next to the memorial of two gallant officers who faced death in Lord Sandwich's flag-ship, and by which he had so often stood to read their inspiring story. The lecturer said a few words of the periods of danger as well as of growth through which the actual fabric had passed. It was at this moment once more in peril. He had entire faith that a monument of national history which stood alone in the world would not be suffered to decay and falL Q 2 220 Br. G. Meymott Tidy [March 2, WEEKLY EVENING MEETING, Friday, March 2, 1888. Edwaed Woods, Esq. M. Inst. C.E. Vice-President, in the Chair. C. Meymott Tidy, Esq. M.B. M.S. M.E.I. (Professor of Chemistry and of Forensic Medicine at the London Hospital, &c.). Poisons and Poisoning. Toxicology is the science of " poisons and poisoning." How comes " toxicology " to mean " the science of poisons " ? The Greek word Toiov (derived perhaps from ruyxavw) signified primarily that specially oriental weapon which we call " a bow." In the very earliest authors, however, it included within its meaning " the arrow shot from the bow." In the first century a.d. in the reign of Nero (a poisoner and a cremation! st), Dioscorides, a Greek writer on Materia Medica, uses the expression to to^lkov to signify " the poison for smearing arrows with." Thus by giving an enlarged sense to the word — for words ever strive to keep pace, if possible, with a scientific progress — we get our modern and significant expression " Toxicology," the science of poisons and poisoning. And there, in that little piece of philology (jo^ov and to^lkov — a bow and a poison), you have not only the derivation of the word, but the early history of my subject. A certain grim historical interest gathers around the story of poisons and poisoning. It is a history worth studying, for poisons have played their part in history. The " subtil serpent " taught men the power of a poisoned fang. History presents poisoning in its first aspect in a far less repulsive form than it has assumed in latter days — (fora world may grow wiser and wickeder withal). Poison was in the first instance a simple instrument of " open warfare." For this purpose our savage ancestors tipped their arrows with poison in order that they might inflict certain death on a hostile foe. It can scarcely be questioned that the poison of the snake was the first material employed for this object. The use of vegetable extracts (such as curarine, the active principle of which is strychnine, and is employed at the present time by certain uncivilised communities) belongs to a later period. And so the first use of poison was for an " open fight." It was reserved for later times to mix the cup of kinship with a treacherous; diabolical venom ! 1888.] on Poisons and Poisoning. 221 " An open fight ! " Is the suggestion (think you) too wild, sup- posing " war chemists " with their powders, their gun-cotton, and their explosives never to have been invented, that nations would have turned for their " instrumenta belli " to toxicologists and their poisons. I claim, however (notwithstanding that in this we missed our chance), no more for my subject than its due, if I attempt to localise the very cradle-room of science as the laboratory of the toxicological worker. Besides snake-poison, the use of animal fluids, either alone or mixed with snake-poison, with which to charge arrows, is pre-historic. Thus in old Greek legend we read how Hercules dipped his arrows in the gall of the Lernaean Hydra to render the wounds they inflicted incurable and mortal, and how at last Hercules himself was poisoned by his wife's present, the tunic of the Centaur Nessus stained with his poisonous blood, which she vainly hoped might restore her husband's affection, but which only procured for him the frightful agonies and tortures of which he died. The use of putrid blood as a poisonous agent and the admixture of the snake-poison with blood constitutes a curious history, when regarded in connection with our present views on septicaemia. The toxic activity of putrid animal fluids seems to have been recognised in very early times. And I suppose these early observations on the effects of putrid blood explain the view almost universally adopted, that blood itself was a poison. Thus the deaths of Psammenitus, king of Egypt (as recorded by Herodotus), and of Themistocles (as re- corded by Plutarch), were said to have been effected by the adminis- tration of bullock's blood. Even Blumenbach, so lately as the middle of the last century, persuaded one of his class (by way of settling the question) to drink seven ounces of warm bullock's blood. The young man (good as were his intentions) did not die a martyr to science. The history of poisons and poisoning, the contents of the first chapter of which I have thus briefly indicated (viz. the toxicity of the snake-poison and of blood), down to the final chapter, which com- mences with the properties and reactions of arsenic, forms a tempting subject for my lecture to-night. The histories of Circe and Medea — of Livia Drusilla and Locusta — of Tiberius and Nero — of the Borgias — of Hieronyma Spara, Tofana, Catherine de Medicis, St. Croix, and a host of other worthies, have proved charming topics for the marvellous- monger. And it would not have been an unworthy subject to bare the truths underlying the stories of generations of story-tellers, obscured as they have become by the demand of ignorant sensa- tionalism and the terrors of a mean superstition. But this is not the subject I have proposed to myself for the discourse to-night. "What is a Poison?" Two diflBculties present themselves in answering this question : 1. The laio Ms not defined a poison, notwithstanding that the law at times demands of science the definition of a poison. 222 Dr. a Meymott Tidy [March 2, I know a case, for example, where a prisoner, indicted for the administration of a poison, escaped, because the scientific witness declined to say that the drug administered by the prisoner was a poison. 2. The popular definition of a poison is far from being a sound, much less a scientific definition. Generally speaking, it comes to this, that " A poison is a drug that kills rapidly when administered in a small quantity." The phrase " a small quantity " as regards weight, and the word " rapidly " as regards time, are as indefinite as the classical piece of chalk as regards size. I define a poison as — " Any substance which otherwise than by the agency of heat or electricity is capable of destroying life either by chemical action on the tissues of the living body, or by physiological action after absorp- tion into the living system." (A) It will be convenient to consider first, WJiat a. poison is not. It is not an agent that destroys life by physical influences, such as heat and electricity. It is not an agent that destroys life by any purely mechanical act (e. g. pins are not poison, although fairly included in the phrase " destructive things "). It is not an agent that destroys life by the mere blocking out of that which is necessary to maintain life (i. c. the action of a substance to be a poison must be more than mechanical). This latter point requires further consideration : — Both nitrogen and carbonic acid destroy life as certainly as they extinguish a burning taper. Yet nitrogen is not a poison, whilst carbonic acid is. Nitrogen simply destroys life by blocking out oxygen. Given the presence of 20 per cent, of oxygen, the 80 per cent, of nitrogen possesses no toxic effect. The carbonic acid, on the contrary, is specifically toxic. The admixture of 20 per cent, or of 80 per cent, of oxygen does not materially alter the case. Oxygen or no oxygen, CO^ is a poison. (B) Consider next, What a poison is. It is an agent capable of destroying life. The use of the phrase deadly poison, is surplusage. If a body bo a poison, it is deadly ; if it be not deadly, it is not a j^oison. My definition limits the mechanism whereby tbe toxic effect is induced, to chemical and physiological actions. I am conscious that this definition suggests classification. Certain is it, that Nature hates classification as truly as she declines definitions. Let us trace some of these mechanisms of toxic activity. I select three illustrations of poisons belonging to different classes. (1) Sulphuric Acid. — If a person swallows sulphuric acid, the tissues with which the acid comes into contact are more or less charred :— 1888.] on Poisons and Poisoning. 223 " more or less," that is, according to the strength of the acid and the time of contact. Charred : — This implies a chemical act, dependent on the power of sulphuric acid to combine with water. The portion of the body thus charred dies. We call this mole- cular death. (This does not imply that the person is dead. Health is disturbed. Health is derived from the old Saxon word " Wholth," signifying entirety. Health implies the perfect rhjthmicity of the bodily functions. It is that condition expressed with charming sim- plicity by Suffolk folk, who describe being " quite well " by the j)hrase, " they feel all over alihe." The charring process (molecular death) has disturbed rhythmicity.) Before long all the members suffer with the charred stomach. The death, localised in the first instance, becomes general, the death of the entire body, i. e. of the person, eventually taking place. We call that somatic death. This is poisoning by sulphuric acid. But the primary act of disturbance — the first interference with the rhythmicity of health — resulted from the chemical power of sulphuric acid to combine with water. It will be evident that the chemical action of a poison depends on the chemical relationships of that poison. (2) Carbonic Oxide. — Carbonic oxide is a true poison. It is a gas that may often be seen burning with a blue flame on the top of a bright fire in the open fire-stove. Its importance amongst poisonous bodies depends on the cir- cumstance that it is evolved in many manufacturing operations (e. g. lime and brick kilns, iron blast furnaces, copper-refining furnaces, &c.), and that it is always present in small quantity in coal gas, constituting its true toxic constituent. What then is the mechanism whereby carbonic oxide destroys life? — The active agent of the blood is its red colouring matter {Esemoglohin). To the chemist this substance abounds in wonder. We have reason to believe that haemoglobin is formed from the albumenoids, the synthesis of which albumenoids is limited to the vegetable. Essential as the albumenoids are to animal life, the animal is dependent for their formation on the synthetical processes taking place in the plant laboratory. The animal, however, can transmute one albumenoid into another (e. g. he can change albumen into a peptone), whilst he can also form from them bodies of less com- plicated constitution (e. g. fat) : — in other words, he can lower them in the scale. But, save with one exception, he cannot use them to effect higher synthetical formations. This single exception is h^emo- globin. It is no matter for surprise that a body like haemoglobin — one of the chief actors, so to speak, in the curious drama of life and living — which comes on the scene through a stage opening, of which we neither know construction nor whereabouts — should possess unique chemical properties and relationships. I shall only trouble you this evening with one of these relationships. 224 Dr. C. Meijmott Tidy [March 2, As a general rule, a substance that combines with oxygen with difficulty, parts from it with ease, and vice versa. It is difficult to make gold combine with oxygen, but it is easy to decompose oxide of gold. Potassium easily combines with oxygen, but it required the genius of a Davy, and the resources of the Eoyal Institution, to separate potassium and oxygen. In haemoglobin, however, we have a substance that combines with, and delivers up, its oxygen (i. e. is oxidized and reduced) with almost equal facility under similar conditions. Upon this and other chemical characteristics of haemoglobin — as the oxygen-receiver, the oxygen-carrier, the oxygen-deliverer, the carbonic-acid receiver, carrier, and deliverer — the act of living depends. In other words, life depends on the integrity of the haemoglobin — on the rhythmicity of those chemical processes, in effecting which haemoglobin is the primary worker. With these facts before us, let us turn to the toxic action of carbonic oxide. The haemoglobin at once seizes upon and combines with the carbonic oxide, carbonic-oxide-haemoglobin being formed. Two difficulties arise : 1. The haemoglobin, saturated with carbonic oxide, cannot combine with oxygen. Regarding haemoglobin as a common carrier, the car- riage is full. 2. The haemoglobin, being saturated with carbonic oxide, cannot get rid of the carbonic oxide under the ordinary conditions of respira- tion and circulation. Again, regarding the haemoglobin as a common carrier, the vehicle, full up, cannot be unloaded. To put all this in scientific phraseology, carbonic-oxide-haemo- globin is a comparatively stable compound, being neither decomposed by the presence of an excess of oxygen (as in the lungs) nor by carbonic acid. What must happen ? The man dies because the integrity of the haemoglobin has been disturbed — because the normal sequence of its oxidation and reduction has been interrupted by the formation of carbonic oxide haemoglobin. We call the result of all these chemical actions and interferences, poisoning by carbonic oxide. 3. Strychnine (the poison derived from St. Ignatius' Bean). How does strychnine act ? Wo know sadly little about it — so little that we use the phrase " physiological action " to express out want of knowledge. But we know something. A marked chemical characteristic of strychnine is its power to com- bine with oxygen when the oxygen is presented to it in a nascent form. Note then the conditions. Strychnine is in the body. There is also present in the blood, haemoglobin loosely combined with oxygen, which oxygen the haemoglobin is always ready to give up on first demand. We are able to trace this action, and to see that the period of the primary strychnine fit coincides with the reduction of the hsemoglobin. 1888.] on Poisons and Poisoning. 225 Why (you ask) does that kill ? I cannot tell you. It is the highest form of knowledge to see the limits of positive knowledge, and to make that the starting-point for fresh inquiry. From what I have said, it will be evident that my object has been to trace toxic energy to the chemical action of poisons on living tissues or fluids. The phrase " physiological action " must not be understood as implying any theory re modus operandi. There is a danger lest the phrase " physiological action " should be employed, or regarded, as explanatory. It no more explains (be it remembered) the action of certain drugs on the living body than the word catalysis explains fermentation. There naturally follows on what I have said respecting this chemical action of poisons, the following important question : — Given knowledge of certain properties of the elements, such as their atomic weights, their relative position according to the periodic law, their spectroscopic characters, &c. ; — or given knowledge of the chemical composition, the molecular constitution, together with the general chemical and physical properties of compounds, in other words, given such knowledge of the element or compound as may be learnt in a laboratory — does such knowledge afford any clue whereby we may predicate the probable action of the element or of the com- pound respectively, on the living body ? 1st. Let us limit our attention to ike elements. The starting-point of this inquiry was the toxic properties of the metals. The work of Blake (1841) in this direction was afterwards extended by Eabuteau (1867). Their observations led them to the general conclusion, that "the physiological activity of the metals increased with their atomic weight." I'his broad general statement was modified at a later period by noting that the reverse was the case with certain groups of metals. Thus potassium (39) is more poisonous than sodium (23), and barium (137) more poisonous than calcium (41). These facts led Eabuteau to the conclusion, that any com- parisons of toxicity must be limited to the metals belonging to the same group. Husemann and Eichet, however, pointed out that even this rule did not hold good, seeing that lithium having an atomic weight of 7, was far more poisonous than either sodium or potassium. Experiments on the metals were further conducted by Eichet with the metallic chlorides. Grain by grain, at intervals of forty-eight hours, he added the chlorides to water in which he kept fish of a given kind. He then recorded the maximum strength of the solution of the metallic chloride in which these said fish would live for forty-eight hours. The conclusion at which he arrived was that the limits of the toxicity of a metal bore no relationship either to its atomic weight, or to any other chemical or physical characteristic of the metal. Bouchardat and Stewart Cooper, in a similar manner, experimented with the non-metals. Selecting the haloid group of elements, they 226 Dr. a Meymott Tidy [March 2, noted that their toxicity was inversely to their atomic weight, fluorine (19) being the most poisonous, and iodine (127) the least poisonous of the group, chlorine (35 • 5) and bromine (80) occupying their proper intermediate positions. But here again the group theory was inevitable. What was true of monad elements was not true of the elements of higher atomicity, the toxicity of selenium (79) being far greater than that of sulphur (32). With these facts before us there arises this question, Was a relationship to be expected between physiological action and atomic weight ? One poison acts on muscles — a second on nerves and nerve- centres — a third on the blood : — Is it likely, even supposing a relation- ship to exist between a certain group of elements and a given organ or a given structure, that the relationship would be the same in the case of all organs and all structures? These researches (the oiitline of which I have briefly indicated) suggest this much to future observers, viz. : First of all group your poisons according to their methods of operation, and then see how far the degree of toxicity of the terms of any one group show relationship to the atomic weights of such group. But the difficulties of comparison thicken, when we consider the physiological action of certain allotropic modifications of the elements. Thus compare yelloiu phosphorus, a body readily inflammable, soluble in bisulphide of carbon, firing by contact with iodine, with red phosphorus, a body at variance with the yellow variety in the three respects named. Nor is this all. For yellow phosphorus is an active poison, two grains being a certainly toxic dose, whilst red phosphorus is an absolutely inert body. Take a second illustration. In its ordinary form oxygen plays the part of a life sustainer. But oxygen is only a life sustainer in its common form and at ordinary pressure. On this latter point I have no time to dwell, save to mention that if an animal be exposed to oxygen at three pressures, the resulting symptoms are not unlike those induced by strychnine. There is, however, an allotropic form of oxygen called ozone. The physiological action of ozone was the subject of a communication to the Royal Society of Edinburgh by Dcwar and McKendrick (1873). Their experiments were made on both cold and warm-blooded animals, including amongst the latter themselves and their assistants. The results are remarkable, more particularly when we remember that the air with which they operated, at most only contained 10 ])ev cent, of ozone. Placing a large frog in a jar of air, and then ozonizing the air, the frog in about half a minute closed its eyes, the respirations fell from 96 to 8 per minute, and the body temperature was lowered 4° or 5° C. The animal recovered in about 8 minutes, when pure air was admitted into the receiver. Death resulted if the animal was exposed for any lengthened period to the action of the ozonized air. As regards the action of ozone on warm-blooded animals, Dewar 1888.] on Poisons and Poisoning. 227 records certain personal experiences, chief amongst wLicIi were a tendency to breathe slowly, an enfeebled pulse, and fits of sneezing. But now comes the curious part of the story, viz. that at the 'post- mortem on the animals that died under the influence of ozone, the blood was found to be venous. (The results were similar when pure ozonized oxygen was employed.) It is most remarkable that the post-mortem appearances of death from an intensified oxygen should resemble those of death from carbonic acid. I give these illustrations to show why there should be reason to doubt whether the physical or chemical properties of an element can ever suggest either toxic activity or physiological action. 2nd. Compounds. Is there any relationship between the chemical composition or constitution of a compound body and its physiological action ? The first series of researches on this question was directed to determining whether, in the case of a salt, the acid or the base was, physiologically, the most important ingredient (Blake 1811). No doubt most often the active agent of a salt is the base, but this is by no means uniformly the case. Probably the solubility of a compound and the different proportions of acid to base in the salt (i. e. whether the compound in question be an acid or a basic salt) are agencies which also help to determine the toxicity of the body and its j^hysiological action. A second series of experiments was made by Blake for the purpose of showing that, given a series of isomorphic salts, the intensity of physiological action increased with the molecular weight. He further contended that salts crystallising in different forms had different physiological actions. On this basis he constructed a series of nine groups of salts, each group being characterised by special physiological actions, insisting with much reason that we j)ossess in living matter a reagent (so to speak) capable of aiding us in our investigations into the molecular properties of chemical compounds. If from molecular constitution you can determine physiological action, probably from physiological action, conversely, you may determine molecular constitution. Another series of experiments in a similar direction were made by Schoff on the Continent, and by Fraser and Crum Brown in this country. Of these experiments the most important are those indicating how from bodies of vastly different physiological action you may obtain derivatives having similar j)roperties. For example, the physiological action of strychnine is primarily exerted on the spinal cord. As a result, convulsions occur as a prominent symptom. But if we introduce into the strychnine molecule a methyl group (forming methyl-strychnine), the action of the drug is altered — methyl-strychnine paralysing (strychnine stimu- lating) the motor nerves. But here comes a curious fact. If we take morphine, or nicotine, 228 Dr. a Meymott Tidy [March 2, or atroj)me, or quinine, or veratrine (none of which bodies arc com- parable in their physiological action to strychnine), and convert them into their methyl derivatives, the methyl compounds formed (viz. methyl-morphine, methyl-nicotine, &c.) are comparable in their physiological action to methyl-strychnine. We must admit these experiments to be striking. One treasures any ex23eriment suggestive of the chemical constitution of a body indicating physiological action. But again: — The true physiological action of a drug is not so much its general as its selective action, this selective action being largely dependent on the dose administered and the mode of administration. For example : Inject into the circulation of a frog a small dose of veratrine, great muscular stiffness results, a large dose similarly administered not producing this effect. And now change the method of administration : Apply the small dose directly to the muscle, you get no symptom ; but apply the large dose directly, and great muscular stiff'ness results. Here see the modifying influence of dose and of the mode of administration. Again, the difficulty of " allotropism " in the case of elements, finds its counterpart in " isomerism " in the case of compounds. Thus cyanogen and paracyanogen are bodies of identical percentage composition, and yet cyanogen is one of the most poisonous of gases, whilst paracyanogen is one of the most inert of solids. Or, again, take piperin and morphine. These bodies are of identical percentage and molecular composition. They agree (it is true) in being poisons. But how vastly different their physiological action ! — the one an extreme irritant, the other a powerful narcotic. I fear we must admit that, as no a priori reasoning could predict that by combining copper and sulphuric acid a blue salt would be formed, so no a priori reasoning, no knowledge of chemical constitu- tion, can predicate what will be the special organ on which any given poison will act, nor, even supposing that the organ upon which the chemical activity of the drug will be exerted be known, what will be the nature of such chemical action. The science of drugs, like the science of chemistry, is, and must ever remain, an experimental science. And, be it remembered, the poisons of the toxicologist are the medicines of the physician. Physiological action is a subject-matter for experiment. Let the guard be jealously set and as rigidly maintained to prevent cruelty to animals ; but ask yourselves, whether to rob the higher creation of life and health rather than that one of the lower creation should suffer, be not a refinement of cruelty — the cruelty of cruelties ? " Are ye not of much greater value than they ? " speaks a still small voice amidst the noisy babble of well-intentioned enthusiasts. Two general observations are suggested. And this first : The later age history of poisoning is the history of a profession. This 1888.] on Poisons and Poisoning. 229 profession we find closely associated, not only with the profession of medicine (the art of healing), but with witchcraft, incantation, and charms. The threefold arts of poisoning, witchcraft, and medicine, moreover, became so closely allied to religion, as to claim, each and all, the shield of a sacred sanction and the protection of a Divine voice. Even that very word <^ap/xaKi9, the Greek for ' a dispenser of medicines,' is the same word used to imply ' a witch ' and ' a poisoner* The modern scientist has once and for ever shattered the bond that united science with superstition. It was a special ministry of science to teach men that in the preparation of medicines the pharmacist required no stuffed crocodile to preside over the mysteries of his laboratory, nor incantation to give virtue to his drugs ! And this secondly : The villanies of the early poisoners can never again be practised in the light of the science of the nineteenth century. Science can and has done what legislation could never do. The Hebrew Scriptures speak of a time when " the sucking child shall play on the hole of the asp, and the weaned child shall put his hands on the basilisk's den " (Is. xi. 8, Eev. Ver.). Is not science working out some such consummation as this ? I claim that a science which, like a blood-hound, can track with cunning scent the minutest atom of a poison in the body, is helj)ing forward the day when poison shall cease to be the instrument of a secret treachery, because there are eyes it cannot hope to evade, and a science whose investigations it will not dare to defy. [C. M. T.] 230 General Monthly Meeting. [March 6, GENERAL MONTHLY MEETING, Monday, March 5, 1888. Edward Woods, Esq. M. Inst. C.E. Vice-President, in the Chair. Frederick Beer, Esq. Thomas Buclmey, Esq. F.E.A.S. The Hon. Justice Day, J. E. Drower, Esq. George Beloc Ellis, Esq. David Charles Guthrie, Esq. Eobert George Hobbes, Esq. Graham Hutchison, Esq. J.P. Mrs. William Moir, Percival Arthur L. Pryor, Esq. Vincent Joseph Robinson, Esq. Alfred Richard Sennett, Esq. Louis Sterne, Esq. George Philip Willoughby, Esq. were elected Members of the Royal Institution. The Special Thanks of the Members were returned for the following Donation to the Fund for the Promotion of Experimental Research : — Professor Dewar, £100. The following Arrangements for the Lectures after Easter were announced ; — Charles Waldstein, Esq. M.A. Ph.D. — Three Lectures on John Ruskin ; on Tuesdays, April 10, 17, 24. Walter Gardiner, Esq. M.A. — Three Lectures on The Plant in the War OF Nature; on Tuesdays, May 1, 8, 15. SmNET CoLTiN, Esq. M.A. — Three Lectures on Conventions and Conven- tionality IN Art; on Tuesdays, May 22, 29, June 5. Professor Dewar, M.A. F.R.S. M.B.I. Fullerian Professor of Chemistry, R.I. — Six Lectures on The Chemical Arts ; on Thursdays, April 12, 19, 2G, May 3, 10, 17. Professor T. G. Bonnet, D.Sc. LL.D. F.R.S.— Three Lectures on The Growth and Sculpture of the Alps (The Tyndall Lectures); on Thursdays, May 24, 31, June 7. Carl Armbruster, Esq. — Seven Lectures on The Later Works of Richard Wagner (With Vocal and Instrumental Illustrations) ; on Saturdays, April 14, 21, 28, May 5, 12, 19, 26. Professor C. E. Turner, of the University of St. Petersburg.— Three Lectures on Count Tolstoi as Novelist and Thinker; on Saturdays, June 2, 9, 16. 1888.] General Monthly Meeting. 231 The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz : — FROM The Governor- General of India — Geological Survey of India : Palssntologia Indica, Ser. X. Vol. IV. Part 3. 4to. 1887. Records, Vol. XX. Part 4. 8vo. 1887. Memoirs, Vol. XXIV. Part 1. 8vo. 1887. Manual of the Geology of India, Part IV. Mineralogy. By F. R. Mallet. Svo. 1887. The French Government — Documents Inedits sur I'Histoire de France : Lettrcs de Catherine de Medicis. Par Cte. Hector de la Ferriere. Tome III. 1567-70. 4to. 1887. Abel, Sir Frederick, C.B. D.C.L. F.R.S. M.R.I, (the Author)— Accidents in Mines. (Proc. Inst .Civil Kng. 1886-8.) Svo. 1888. Academy of Natural Sciences, Philadelphia — Proceedings, 1887, Part 2, Svo. Accademia dei Lincei, Reale, Roma — Atti, Serie Quarta : Rendiconti. Vol. III. 2" Semestre, Fasc. 8, 9. Svo. 1887. American Academy of Arts and Sciences — Memoirs, Vol. XL Part V. No. 6. 4to. 1887. Astronomical Society, i?o;/aZ— Monthly Notices, Vol. XLVIII, No. 3. Svo. 1888. Australian Museum, Sydney — Descriptive Catalogue of the Medusss of the Austra- lian Seas. By R. von Lendenfeld. Svo. 1887. Banhers, Institute q/"— Journal, Vol. IX. Part 2. Svo. 1888. British Architects, Royal Institute of — Proceedings, 1887-8, Nos. 8, 9. 4to. Cambridge Philosophical Society — Proceedings, Vol. VI. Part 3. Svo. 1888. Canada Geological and Natural History Survey — Catalogue of Canadian Plants, Part III. Apetalse. By J. Macoun. Svo. 18S6. Chemical Society — Journal for February, 1888/ Svo. Crisp, Frank, Esq. LL.B. F.L.S. &c. M.R.I, {the Editor)— S omn^^. of the Royal Microscopical Society, 1887, Part 6a ; 1888, Part 1. Svo. Editors — American Journal of Science for February, 1888. 4to. Analyst for February, 1888. Svo. Athenaeum for February, 1888. 4to. Chemical News for February, 1888. Svo. Chemist and Druggist for February, 1888. Svo. Engineer for February, 1888. fol. Engineering for February, 1888. fol. Horological Journal for February, 1888. Svo. Industries for February, 1888. fol. Iron for February, 1888. 4to. Murray's Magazine for February, 1888. Svo. Nature for February, 1888. 4to. Revue Scientifique for February, 1888. 4to. Scientific News for February, 1888. 4to. Telegraphic Journal for February, 1888. Svo. Zoophilist for February, 1888. 4to. Franklin Institute — Journal, No. 746. Svo. 1888. Geographical Society, J?o?/aZ— Proceedings, New Series, Vol. X. No. 2. Svo. 1888. Geological Society — Quarterly Journal, No. 173. Svo. 1888. Harden, Edward B. Esq. (the Author) — The Construction of Maps in Relief Svo 1887. Linnean Society— J omnnl, Nos. 130, 137, 138. Svo. 1887. Manchester Geological Society — Transactions, Vol. XIX. Part 13. Svo, 1887. Ministry of Public Works, Rome — Giornale del Genio Civile, Serie Quinta Vol. I. No. 12. Svo. And Disegni. fol. 1887. ' Montpellier Academic des Sciences et Zef^res— Memoires, Tome XI. Fasc 1 (1885-6). 4to. 1887. 232 General Monthly Meeting, [March 5, New York Academij of Sciences — Transactions, Vols. I. II. and V. 8vo. 1881-6. Numismatic Society — Chronicle and Journal, 1887, Part 4, Svo. 1887. Pharmaceutical Society of Great Britain — Journal, February, 1888. 8vo. Calendar for 1888. Svo. Photographic Society — Journal, Vol. XII. No. 4. 8vo. 1887. Eio de Janeiro Observatory— 'Rcvista, No. 1. Svo. 1888. Annuario, 1885, 1886, 1887. 16to. Boyal Society of Ed inhurqh— Transactions, Vol. XXX. Part 4 ; Vol. XXXII. Parts 2-4; Vol. XXXIII. Part 1. 4to. 1883-7. Proceedings, Nos. 121-123. Svo. 1885-6. lioyal Society of Xo?i(?07i— Proceedings. Nos. 261, 262. Svo. 1S87-8. Philosophical Transactions, Vol. CXXXVIII. 4to. ISSS. Science and Education Library, South Kensington Museum — Catalogue of Scientific Periodicals. Svo. 1886. St. Petersbourg, Academic Impd'riale des Sciences — Memoires, Tome XXXV. Nos. S, 9. 4to. 1887. Society of Arts — Journal, February, 1888. Svo. Statistical Society — Journal, Vol. L. Part 4. Svo. 1887. Telegraph Engineers, Society o/— Journal, No. 69. Svo. 1887. United Service Institution, Po'yal— J ourna], No. 142. Svo. 1888. United States Geological Survey — Mineral Eesources of the United States for 1886. Svo. 1887. Vereins zur Beforderung des Gewerhfleisses in PreMsse?i— Verhandlungen, 18S8: Heft 1. 4to. Wild, Dr. H. {the Director') — Annalen der Physikalischen Central-Observatoriums, 1886, Theil 2. 1887. Wright and Co. Messrs. John (the Publishers)— The Medical Annual, 1888. Svo. Yorhshire Archciological and Topographical Association — Journal^ Part 39. Svo. 1888. 1888.] Mr. Leslie Stephen on S. T. Coleridge. 233 WEEKLY EVENING MEETING, Friday, March 9, 1888. Edward Woods, Esq. M. Inst. C.E. Vice-President, in the Chair. Leslie Stephen, Esq. M.A.. S. T. Coleridge.* In the period which intervened between the Great War and the first Eeform Bill, there were two centres of intellectual light in England. Jeremy Bcntham, in his cheerful old age, reached his eightieth birthday in 1828, still, as lie phrased it, codifying like any dragon, solving all problems by the application of his famous formula alDout the greatest happiness of the greatest number, and adding day by day to the vast piles of manuscript which were to embody the principles of all future legislation. To his hermitage in Westminster were admitted a little group of chosen disciples, the stern political econo- mists, rigid utilitarians, and energetic reformers, some of whom were in \h.e coming years to assume the title of philosophical radicals. Another band of enthusiasts sought a drifferent shrine. They listened to an oracle which taught them that utilitarianism was " moral anarchy," political economy a "solemn humbug," radicalism the direct road to ruin, and true wisdom only to be found in regions of contemplation which Benthara could never enter — for a reason analogous to that which forbids pachydermatous quadrupeds to soar into the empyrean. We know pretty well what was the manner of man at whose feet these disciples sat. The keenest of contemporary observers has left a picture which must be laid under contribution for every description of Coleridge. Carlyle saw an old man — though in point of actual years he was Bentham's junior by nearly a quarter of a century — with the brow of a philosopher and the eye of a poet, but with the irresolute flabby mouth of a sensuous dreamer of dreams, consuming cups of tea, lukewarm but better than he deserved, or strolling, corkscrew fashion, along both sides of a garden path, un- able to make up his mind to either. You put him a question ; he re- plied by accumulating " formidable apparatus, logical swim-bladders, * It seems desirable to say that some of the statements in the Lecture rest upon an examination of original documents, many of which have not hitherto been accessible to biographers. I owe ray knowledge of them chiefly to Mr. Dykes Campbell, whose knowledge of the subject is most minute and exhaus- tive. A complete biography still remains to be written ; it may be expected from Mr. Ernest Coleridge, who is in possession of his grandfather's MSS. — Leslie Stephen. Vol. XIL (No. 82.) r 234 Mr. Leslie Stephen [March 9, transcendental life-preservers, and other precautionary and vehiculatory gear for setting out ; " but rambled into the universe at large, treated you " as a mere passive bucket, to be pumped into " (fancy a Carlyle for a passive bucket !), and finally left you " swimming and fluttering in the mistiest wide unintelligible deluge of things, for the most part in a rather profitless uncomfortable manner." Yet, at times, we are told, " balmy sunny islets, islets of the blest and intelligible," would rise out of the haze ; and upon these islets the enthusiastic Sterling and others would try to cast anchor. Had they reached the solid foundation of creation, or had they, like Milton's pilot of the small night-foundered skiff, mistaken some metaphysical Kraken for the permanent frame- work of things ? That question may be answered dogmatically by any one who pleases. Immovable limits of time and caj)acity forbid me from attempting to answer it now. My excuse for venturing to say some- thing of Coleridge — certainly one of the most fascinating and most perplexing figures in our literary history — is simply this : I have been forced to investigate with some care the details of his career ; and I ought to be able not only to answer the question but to provide a little " vehiculatory gear " towards answering it. Coleridge's philosophy must of course be judged by considerations extraneous to his personal history. Yet I think, as a professional biographer is in duty bound to think, that philosophy is, more often than philosophers admit, the outcome of personal exiDcrience ; and Coleridge's singular history may throw some light uj)on his teaching. Here we meet the hagiologist and the iconoclast, the twin plagues of the humble biogi'apher. The hagiologist burns incense before his idol till it is difficult to distinguish any fixed outline through the clouds of gorgeously- tinted vapour. Coleridge thought himself to have certain failings. His relations fully agreed wdth him. His worshippers regard these meek confessions as mere illustrations of the good man's humility, and even manage to endow the poet and philosopher with all the homely virtues of the respectable and the solvent. To put forward such claims is to challenge the iconoclast. He, a person endowed by nature with a fine stock of virtuous indignation, has very little trouble in j^icturing the poet-philosopher as a shambling, unreliable, indolent voluptuary, to whom an action became impossible so soon as it presented itself as a duty, and who, even as a man of genius, must be condemned as unfaithful to his high calling. And so we raise the usual edifying discussion as to the privileges of genius. Do they include superiority to the Ten Commandments ? Can you expect a poet to confine himself to one wife ? May a man neglect his children because he has written the ' Ancient Mariner ' and ' Christabel ' ? — points of casuistry, of which, with your leave, I will postpone the consideration to a future occasion. For my purpose, it is enough to ascertain the facts. I have not to decide whether Coleridge should receive excommunication or canonisation ; whether he deserved to go straight to heaven or to 1888.] on S. T. Coleridge. 235 pass a period — and, if so, how long a period — in purgatory. It is difficult to settle such questions satisfactorily. I desiderate an accu- rate diagnosis, not a judicial sentence. Coleridge sinned and repented. I take note of sin and of repentance as indications of cliaracter. I do not pretend to say whether in the eye of Heaven the repentance would be an adequate set-off for the sin. But I premise one apology for anything that may sound iconoclastic, and which I think is worth the consideration of the amiable persons who undertake to rehabili- tate soiled reputations. A man's weakness can rarely be overlooked without underestimating his strength. If Coleridge's intellect were, as De Quincey said in his magniloquent way, " the greatest and most spacious, the subtlest and most comprehensive, that has yet existed among men " (what a philosopher one must be to pronounce such a judgment ! ), why were the results so small ? Because the ethereal soul was chained to a fleshly carcase. To deny this is to force us to assume that what he did was all that he could do. You must either exaggerate his actual achievements beyond all possible limits, or save your belief in his potential achievements, by admitting that his intel- lect never had fair play. Let us consider the antecedents of the prophet of Highgate Hill. Was there ever a young man fuller of intellectual promise or of per- sonal charm thtin the youth of twenty-five, who, in 1797, rambled through the Quantocks discussing and composing poetry with Words- worth ? Circumstances apparently urrfavourable had only served to stimulate his intellectual growth. Separated from his family in infancy, to become one of the victims of our public school system — ill-fed, ill-nursed, and ill-taught at Christ's Hospital ; urged upon the treadmill of a sound classical education by a rigid schoolmaster, he had assimilated with singular aptitude whatever intellectual food had drifted within his reach. He had caught glimpses of high meta- physical secrets ; he had peered into the mysteries of medical practice ; he had bolted a miscellaneous library whole ; he had been infected with poetical enthusiasm by the study of that minute day- star, W. L. Bowles ; and he had completed his training by falling desperately in love with the inevitable sister of a schoolfellow. It is a comfort to reflect that the best regulated systems of education break down somewhere. Coleridge, it would have seemed, ran every risk of being driven sheep-like along the dull highroad of Latin grammar. Nature had prompted him to leap the fences, to expatiate in the wide fields of intellectual and imaginative pasture, and to derive a keener zest for his nourishment from the knowledge that the indulgence was illegitimate. Cambridge, the mother of j^oets, received him with the kindness she has so often shown to her children. We — I speak as a Cambridge man — we flogged (or nearly flogged) Milton into republicanism ; we disgusted Dryden into an anomalous and monstrous preference for Oxford; we bored Gray till, half stifled with academic dulness, he sought more cheerful surroundings in a country churchyard ; we left Byron to the congenial society of bis B 2 236 Mr. Leslie Sfcplien [March 9, bear ; we did nothing for Wordsworth, except, indeed, that we took him to Milton's rooms, and there for once (it must really have done him some good) induced him to take a glass too much ; and we, as nearly as possible, converted Coleridge into a heavy dragoon. We ordered him to bow the knee to Euclid, and to Newton's Principin, the only idols whose merits were altogether beyond his powers of aj^preciation, and by such kindness in disguise induced him to plunge into a precocious breach with the proprieties. A fellowship might have converted him into a solid Church and State don, an oracle of the Combination Eoom, and a sound judge of port wine. We sternly withheld the temptation. A reformer has to start in life as a rebel. Coleridge sympathised with the rebellious William Frcnd, who was being banished from Cambridge for excessive liberalism. He offered his youthful incense to Priestley, the " patriot and saint and sage " — so the young enthusiast called him — who was soon to be expelled by the exuberant loyalty of Birmingham from an ungrateful country. Though never a Jacobin, he became what, in some form or other, a young man ought to become — an enthusiast for the newest lights, a partisan of the ideas struggling to remould the ancient order and raise the aspirations of mankind. The Master of the College shook his reverend hcarl, kindly enough at times, at the lad's vagaries, and forgave him even for that preposterous attempt to become a trooper which never enabled him, with all his subtlety of distinction, to form any clear conception of the ditference between a horse's head and its tail. But he could not run in the regular track. He was thrown into the chaotic world to sink or swim by his unassisted abilities. No man had, in some ways, a better floating apparatus. The poetic vein, soon to manifest itself in his best work, was indeed still turbid with the alloy of didactic twaddle. But already he had the versatility, the inherent vitality of intellect, the power of embodying philosophic thoughts in poetic imagery, which made him unrivalled in monologue. He talked better, I am apt to think, with his chum, Charles Lamb, at the " Cat and Salutation," than he ever talked to his worshippers at Highgate Hill. A man is at his best before he is recognised. Coleridge's early letters and essays show the fulness and intellectual vigour, without the too elaborate and slightly sanctimonious circum- gyrations, of his later effusions. And his genius was such as implied a double portion of the power of making friends, which, with most of us, wanes so lamentably as the years go by. Lamb, his earliest and latest friend, was already devoted to this brilliant school- fellow ; and if Lamb was an easy conquest, men of less conspicuously tender nature were equally attracted. He had only to meet Southcy at Oxford to swear at once an eternal friendship — a friendship to be cemented by a regeneration of the world. Coleridge was to be the Plato of a new society to be founded in the wilds of America. There a short and healthy space of daily toil was to provide all that was necessary for a band of poets and j^hilo- sophers, too benevolent to care for separate property, and worthy 1888.] on S. T. Coleridge. 237 founders of an Arcadia of i)Gi'fect simi)licity, refinement, and equality. As for tlie Eves of the Paradise, were there not three Miss Frickers ? Coleridge ^repelled for a time the too obvious foreboding that Pan- tisocracy was but a province of dreamland. Dreamland was his reality. For the demands of butchers and bakers he had still a lordly indiiference. He had the voice which could charm even a publisher. The prim and priggish Cottle was at once annexed by Coleridge, and all the natural caution of a tradesman did not with- hold him from promising a guinea for every hundred lines to bo pro- duced by a still untried new poet. What were one hundred lines to the genius which could turn off an act of a tragedy in a morning, and which soon afterwards could build the shady j)alace of Kubla Khan in a dream? Coleridge was justified, in point of bare pru- dence, in marrying at once on the prospect. Somehow the poetry did not come so fast as the bills. But Coleridge had other strings to his bow. He set up as a lecturer and journalist. His marvellous eloquence condescended for the nonce to wile i^romises of subscrip- tion even from dealers in tallow ; and the philosopher — not without a humorous sense of his own absurdity — became a successful commercial traveller. The newspaper of course collapsed almost on the sj^ot. All the arrangements were absurd, and Coleridge's eloquence proved to bo somehow uncongenial to the tallow-dealing interest. But meanwhile, in the co.u'se of his journey, Coleridge had incidentally and, as it were, by the mere side glance of his 9ye, swept up Charles Lloyd, son of a rich banker, who, fascinated and enthralled, left the bank to become an inmate of his teacher's house, and, no doubt, a contributor to its expenses. Poole, a most public-spirited and intelligent man, offered him an asylum at Nether Stowey. The Unitarians, to whom he more or less belonged, were ready to open their pulpit to a preacher whose eloquence promised to rival even the most splendid traditions of the refined age of Leighton and Jeremy Taylor. Hazlitt, not yet soured and savage, heard Coleridge preach in 1798 ; and tolls us in true Hazlittian style how his voice rose like a storm of rich distilled perfumes ; how he launched into his subject like an eagle dallying with the wind; how, in brief, poetry and philosophy had met together, truth and genius had embraced under the eye and with the sanction of reason. The Unitarian firmament was too cramped for this brilliant meteor ; the philosophy expounded from the jnilpits seemed to him meagre and rigid ; and, while hesi- tating, he received an offer from the generous Wedgwoods, anxious to spend some joart of their wealth in the j^atronage of genius. Rumours had reached England by this time that a great intellec- tual light had arisen in Germany. The Wedgwoods gave Coleridge a modest annuity, unfettered (as I can now say) by any condition whatever, a fact which makes the subsequent withdrawal a harsher measure than has been supposed. Coleridge resolved to go to Germany, catch the sacred fire of the Kantian philosoi)hy, and return to England to regenerate the mind of his countrymen. He started 238 -^**- Leslie SUplien [March 9, in September, 1798, when he was just twenty-six, in company with the friend who alone could be compared to him in intellectual 2)ower. Wordsworth had been attracted, as Lamb and Southey had been attracted before him. Coleridge and Wordsworth had discussed the principles of their common art ; and Coleridge had applied them in those wonderful poems, the ' Ancient Mariner ' and ' Christabel ' (the first part), which were to be but the prologue to a fuller utter- ance; a wonderful prologue, for, though followed by nothing, it remained unique and inimitable. Coleridge was not yet deterre, as Pope said of Johnson ; the ordinary critics had only a passing smile or sneer for the little clique which published its obscure utterances in a provincial town. Monthly and critical reviewers — the arbiters of taste — would have been astonished to hear that Coleridge and Wordsworth and Lamb and Southey would soon stand in the very front ranks of English literature ; and he must have a clearer con- science than I who would cast a stone at critics for not at once detecting the first germs of rising genius. But, as ex post facto prophets, we are able to see that Coleridge already had not only given proofs of astonishin*^ power, but had won what was even more valuable, the true sympathy and cordial affection of young men who were the dis- tinct leaders of the next generation. Even material supj)ort was not wanting from such men as Poole and Wedgwood sufiicient to ensure a fair start for the little band of prophets. We should have been justified in foretelling, with unusual confidence, a career of surpassing brilliancy for the youth, of whom it seemed only questionable whether he would choose to be a second Bacon or a second Milton. And if, at that time, any one could have shown us the same Coleridge at a distance of eighteen years, the worn, depressed, pre- maturely aged man who took up his abode with Gillman in 1816, we should have been shocked, and yet, perhaps, have been able to utter our complacent " I told you so." What so far had been the achieve- ments of the most brilliant genius of the generation : a man not only of surpassing ability, but of surpassing facility of utterance ; a man whom to set going at any moment was to unlock a perpetually flowing fountain of abounding eloquence ? A few newspaper articles and some courses of lectures, he said in 1817, constituted his whole publicity. It may be added that he had jotted down on the margins of books enough detached thoughts to have made some volumes of admirable reflections. But he had achieved nothing to suggest concentrated thought or sustained labour. In a shorter period Scott poured out the whole of the AVaverley novels, besides dis- charging official duties, and writing a number of reviews and miscellaneous works. I say nothing as to the quality. I am simply thinking of the amount of work ; and Coleridge's work cost little labour, for his power of improvisation was among his most mar- vellous faculties. Why, then, was the work so limited in quantity ? The internal facts are sufiiciently significant. After his return from Germany in the autumn of 1799, he wrote some articles which 1888.] 071 S, T. Coleridge. 239 certainly proved that liis intellect was in full vigour, translated * Wallenstein,' and then, in 1800, retired with his family to Keswick. Here at once ominous symptoms begin to show them- selves. A strange disquiet is betrayed in his letters ; there are painful complaints of ill-health ; his poetic inspiration breathes its last in the ' Ode to Dejection.* He sought in vain to distract painful thought by metaj^hysical abstractions; he rambled off in 1804 to spend two years and a half in Malta and Italy. Eeturning to England, he tried lecturing at the Royal Institution, and then settled at Grasmere — fifteen miles of mountain roads from his wife — and repeated his ' Watchman ' experiment by writing the ' Friend.' The youthful buoyancy, even flippancy, has departed, though it shows far riper thought and richer intellectual stores. But weari- ness of spirit marks every page ; the long sentences somehow suggest a succession of stifled groans ; as the enterprise proceeds, it can only be kept up by introducing any irrelevant matter that may be on hand — such as old letters from Germany which happened to be in his portfolio, and an extravagant panegyric upon his patron at Malta, Sir Alexander Ball. The ' Friend ' soon falls dead, and Coleridge drifts back to London. There he makes efforts, pathetic in their impotence, to keep his bead above water. He tries journalism again, but without the occasional triumphs which had formerly atoned for his irregu- larity. He lectures, and is heard with an interest which shows that, in spite of all impediments, his marvellous powers have at least roused the curiosity of all who claim to have an intellectual taste. He has a gleam of success, too, from the production of his old tragedy, ' Eemorse,' written in the days of early vigour. But some undertow seems to be sucking him back, so that he can never get his feet planted on dry land. He retires to Bristol, and thence to Calne, where he seems to be sinking into utter obscurity. He has almost passed out of the knowledge of his friends, when a last despairing effort lands him at Highgate, and there a rather singular transformation, it may seem at first sight, enables him to become the oracle of youthful aspiration, wisdom, and virtue. Painfully, and imperfectly with their aid, he gathers together some fragments of actual achievement — enough to justify a great, but a most tantalising reputation. What was the secret of this painful history ? Briefly, it was opium. Coleridge said so himself, and all his biographers have stated the facts. Without this statement the whole story would be unintelligible, and we could have done justice neither to Coleridge's intellectual powers nor even to some of his virtues. To tell the story of Coleridge without the opium is to tell the story of Hamlet without mentioning the ghost. The tragedy of a life would become a mere string of incoherent accidents. Nor are the facts doubtful. Coleridge, I fear, composed, or invented, for the benefit of Gillman, a certain picturesque " Kendal black drop " — a treacherous nostrum, 240 Mr. Leslie Stephen [March 9, it is suggested, wbicli gave liiin relief in his sufferings at Keswick, and overpowered his will before he had recognised its nature. Tlie truth is, as can be abundantly proved by his letters at the time, that he was taking laudanum in large quantities in 1796, that is when he was just twenty-four, under the pressure of illness, but certainly ■well knowing what he was taking. It was at Keswick, not that he first indulged, but that he first became aware of his almost hopeless enslavement. After reading many painfully conclusive proofs of this j^assion, I confess that I think it less remarkable that his demoralisation in this respect seemed to be complete about 1814, than that he suc- ceeded, under Gillman's care, in so far breaking off the habit as to make a certain salvage from the wreck. I simply take note of these facts, and leave anybody who pleases to do the moralising ; but I am forced to add a few words upon another topic, to which his apologists have resorted in order to extenuate the opium-eating. Briefly, it has been attempted to save his character by abusing his wife. Undoubtedly, as the recently published Coleortou papers prove, there was a complete want of sympathy. The same documents show that it was not, as had been generally supposed, a case of gradual drifting a2)art. Proposals for a regular separation had been made by the time of Coleridge's return from Malta. Coleridge's apologists have said that Mrs. Coleridge was one of lago's women, born " to suckle fools and chronicle small beer," and quite unable to apx)reciate Kantian metaphysics, or even ' Christabel.' A very doubtful legend has been put about, that she once said, " Get oop, Coleridge " (a remark for which one can conceive a sufficient justifi- cation), and no man can be expected to care for a woman who says *' Get oop," or for her children. From letters of hers which I have seen, I am inclined to think that Mrs. Coleridge must really have been a very sensible woman, who worked hard to educate her own childi'cn, and the children of her sister, Mrs. Southey, in French and Italian, and who could express herself in remarkably good English. She was no doubt inappreciative of a genius which could not be set to bread-winning. And moreover, when a man has an ecstatic admiration for another woman, it is nut likely to make his relations to his wife more pleasant. To speak of all this as a moral excuse for Coleridge is to my mind unmanly. If a man of genius con- descends to marry a woman, and be the father of her children, he must incur responsibilities. The fact that he leaves her, as Cole- ridge did, his small fixed income, the balance of her expenses to be made up by his brother-in-law and other connections, is so far to his credit, but does not excuse him for a neglect of those duties, not to be measured in pounds, shillings, and pence, which a husband and father owes to an innocent woman and three small children. Cole- ridge's position was no doubt difficult, but the mode in which he solved the difficulty is a proof that opium-eating is inconsistent with certain homely duties. 1888.] on S. T. Coleridge. 211 An experienced person La> said, " Do not marrj a man of genius." I have no personal interest in that qntsticn, nor will I express any opinion upon it. bnt one is inclined to siy, Don't be his brother-in- law, or his publisher, or his editor, or anything that is his if you care twopence — it is probably an excessive valuation — for the opinion of postliumous critics. But, again, I would avoid moi-alising. I only ask what is the true inference as to Coleridge's character. And that consideration may bring us back to less painful reflections. It is preposterous to maintain the thesis that Coleridge was the kind of person to be held up as a pattern to young men about to marry. Opium had ruined the power of will, never very strong, and any capacity he may have liad — and his versa rility was perhaps incompatible with any great capacity — for concentration on a great task. The consequences of such indulgence had ruined his home life, and all but ruined his intellectual career. But there is also this to be said, that at his worst Coleridge was both loved and eminently lovable. His failings excited far more compassion than indignation. The " pity of it ' expresses the sentiment of all eye-witnesses. He was always full of kindly feelings, never soured into cynicism. The stran ^e power of fascination which he had shown in his poetic youth never deserted Lim. As De Quincey has said : " Beyond all men wbo ever perhaps have lived, he found means to engage a constant succession of most faithful friends. He received the 'services of sisters, brothers, daughters, sons, from the hands of strangers, attracted to him by no possible impulses but those of reverence for his intellect and love for his gracious nature. Perpetual relays were laid aloncj his path in life of zealous and judicious supporters." Whenever Coleridze was at his lowest, some one was ready to help him. Poole, and Lloyd, and Wedgwood, and De Quincey, had come forward in their turn. Through the dismal ye^irs of degradation which preceded his final refuge at Gillman's, the faithful Morgans had made him a home ; tried to break off his bad habits, and enabled him to carry on the almost hopeless struggle. When Morgan himself became bankrupt, it is pleasant to knuw that Coleridge, among whose faults pecuniary meanness had i o place, gave what he could — and far more than he I could really spaie — to help his < Id friend. When he delivered his I lectures or poured out a i amazing monologue at Lamb's suppers, or \ in Godwin's shop, yotmg men, at the age of hero-worship, were already i prepared not only to wonder at the iutellectual display, but to feel their hearts war.red by the real goodness shining through the shattered and imperfectly transparent vessel. Coleridge's letters may reveal Bome part of this charm, though some part, too, of the drawback. His long involved sentences, compared by himself to a Surinam toad with a brood of little toads escaping from his back, wind about in something between a spoken reverie and a sympathetic effusion of confidential confessions. When they touch the practical, e. ^ . publishers' accounts, they are apt to become hopelessly uninteUi^Hble. 2i-2 Mr. Leslie Stephen [March 9, When they expound a vast scheme for a magnum opus, or one of the various magna opera which at any time for thirty years were just ready to issue from the press, as soon as a few pages were transcribed, we perceive, after a moment, that they are not the fictions of the becjszing-letter writer, but a kind of secretion, spontaneously and un- consciously evolved to pacify the stings of remorse. There are moments when he is querulous, but we must forgive them to the man who had been hopelessly distanced in popular fame by his inferiors ; whose attempts at public utterance had utterly collapsed; whose ' Wallenstein ' still encumbered his publisher's shelves ; whose poetical copyrights had been deliberately valued at nil ; and whose name was only mentioned in the chief reviews as a superlative for wilful eccentricity and absurdity. And then, at every turn, we come uj^on frequent gleams, not only of subtle thought and imaginative expression, but of shrewd common sense, and even at times of a genuine humour, which seems to imjily that Lamb was partly serious when he said that Coleridge had so much ' f-f-fun ' in him. After readinc many of the letters, which still remain unpublished, I may say that it is my own conviction that a life of Coleridge may still be put together by some judicious writer, who should take Bos well rather than the ' Acta Sanctorum ' fur his model, which would be as interestinf^ as the great ' Confessions' ; which should by turns remind us of Augustine, of Montaigne, and of Eousseau, and sometimes, too, of the inimitable Pepys or Boswell himself ; which should show the blending of the many elements of a most complex character and a most versatile and opulent intellect ; which should often call forth wonder, and smiles, and sighs, and indignation smothered by pity, in one of those unique combinations which it would take a Shakespeare to portray and act, and defy the skill of a psychologist to define. Only* a faint indication of this is to be found in Coleridge's ' Apologia,' or, as he called it, his ' Biographia Litcraria,' of which I must now say a word. It was written at his very nadir, and published just after he had reached his asylum at Highgate. In this sense it has a special biographical value, though its statements, coloured by the illusions to which he was then specially subject, have passed muster too easily with his biographers. Its aim is chiefly to protest against the neglect of the public and the dispensers of patronage. Such complaints generally remind me of a rifleman complaining that the target persists in keeping out of the line of fire. But if we must pardon something to a man so grievously tried for endeavouring to shift a part of the responsibility upon other shoulders than his own, we must be upon our guard against accepting censures which involve injustice to others. Nothing but Coleridge's strange illusions could be an apology, for example, for his complaints that the Ministry had not rewarded a writer whose greatest successes had been scornful denunciations of their great leader, Pitt. The book, of course, is put together with a pitchfork. It is without form or pro- portion, and is finally eked out with a batch of the old letters from 1888. J on S. T. Coleridge. 243 Germany which he had already used in the ' Friend,' and apparently kept as a last resource to stop the mouths of printers. Now it is remarkable that even at this time, when his demorali- sation had gone furthest, he could still pour out many pages of criticism, quite irrelevant to the professed purpose of the book, and yet such as was beyond and above the range of any living contempo- rary. Coleridge at his worst lost the power of finishing and concen- trating— of which he had never had very much — but not the power of discursive reflection. He must be comj^ared not to a tree which has lost its vital fibre, but to a vine deprived of its props, which, though most of its fruit is crushed and wasted, can yet produce grapes with the full bloom of what might have been a superlative vintage. But there is one fact of the ' Biographia' for which the apology of illusion is more requisite even than for his misstatements of fact. Coleridge has often been accused of plagiarism. I do not believe that he stole his Shakespeare criticism from Schlegel, and, partly at least, for the reason which would induce me to acquit a supposed thief of having stolen a pair of breeches from a wild Highlandman. But it is un- deniable that Coleridge was guilty of a serious theft of metaphysical wares. The only excuse suggested is that the theft was too certain of exposure to be perpetrated. But, as it certainly was perpetrated, this can only be an apology for the motive. The simple fact is that part of his scheme was to establish his claims to be a great meta- physician. But it takes much trouble and some thought to put to- gether what looks like a chain of a ^priori demonstration of abstract principles. Coleridge, therefore, persuaded himself that he had really anticipated Schelling's thoughts and might justifiably appro- priate Schelling's words. He threw out a few phrases about " genial coincidence " — perhaps the happiest circumlocution ever devised for what Pistol called " conveying " — and adopted Schelling in the lump. When he had come to an end of Schelling's guidance, he proceeded — with an infantile simplicity which disarms indignation — to write a solemn complimentary letter from himself to himself, pointing out that the public would have had enough of the discussion, and '• Dear C." politely agreed to drop the subject, with proper compliments to his " afiectionate, &c." And now I come to the very difficult task of indicating, as briefly as I can, the bearing of these remarks upon Coleridge's multifarious activity. It is not possible to sum up in a few phrases the character- istics of a man who wrote upon metaphysics, theology, morals, politics, and literary criticism ; who made a deep impression in all the departments of thought ; whose utterances are scattered up and down in fragmentary treatises, in complex arguments which generally break ofl^ in the middle, and in miscellaneous jottings upon the margins of books ; whose opinions have been difierently interpreted by different disciples, and have in great part to be inferred from his comments upon other wTiters, and can only be intelligible when we have settled what those ^vl•iters meant, and what he took them to 2U My. Leslie Stephen [March 9, mean ; who frequently changed his mind, and who certainly appears, to thinkers of a different order, to add obscurity even to subjects which are necessarily obscure. Nor is the difficulty diminished when, as in my case, the commentator belongs to what must be called the antagonistic school, and is even most properly to be described as a thorough Philistine who is dull enough to glory in his Philistinism. All that I shall attempt is to select a certain aspect of the Coleridgian impulse, and to say what impression it makes upon a radically prosaic mind. The brilliant Coleridge of Nether Stowey, the buoyant young poet-philosopher who had not yet been to Germany, was still a curious compound of imperfectly fused elements. His Liberalism had led him to the Unitarianism of Priestley and the associative philosophy of Hartley. But he had also dipped into Plotinus and into some of the mystical writers who represent the very oj^posite pole of specula- tion. The first doctrine was imposed upon him from without, the other was that which was really congenial to his temperament. For Coleridge was, above all, essentially and intrinsically a poet. The first genuine manifestations of his genius are the poems which he wrote before he was twenty-six. The germ of all Coleridge's utter- ances may be found — by a little ingenuity — in the ' Ancient Mariner.' For what is the secret of the strange charm of that imique achieve- ment ? I do not speak of what may be called its purely literary merits — the melody of versification, the command of language, the vividness of the descriptive passages, and so forth — I leave such points to critics of finer perception and a greater command of super- latives. But part, at least, of the secret is the ease with which Coleridge moves in a world of which the machinery (as the old critics called it) is supplied by the mystic philosopher. Milton, as Penscroso, implores The spirit of Plato to unfold, Wiiat ^Yurlds or what vast SNstems liold The spirit of man that hath lursook Her mansion in this fleshy nook, And of those demons that are found In fire, air, flood, and underground, "Whose powers have a true consent "NVith planet and with element. If such a man fell asleep in his " high lonely tower," his dreams would present to him in sensuous imagery the very world in which the straijge history of the ' Ancient Mariner ' was transacted. It is a world in which both animated things, and stones, and brooks, and clouds, and | lants are moved by spiritual agency ; in which, as he would put it, the veil of the senses is nothing but a symbolism every- where telling of unseen and suiDcrnatural forces. What we call the solid and the substantial becomes a dream; and the dream is the true underlying reality. The difference between such poetry, and the 1888.] on S. T, Coleridge. 215 poetry of Pope, or even of Gray, or Goldsmith, or Cowper — poetry which is the direct utterance of a string of moral, political, or religious reflections — implies a literary revolution. Coleridge, even more distinctly than Wordsworth, represented a deliberate rejection of the canons of the preceding school ; for, if AVordsworth's philo- sophy differed from that of Pope, he still tauglit by direct exposition instead of the presentation of sensuous symbolism. The distinction might be illustrated by the ingenious criticism of Mrs. Barbauld, who told Coleridge that the ' Ancient Mariner ' had two faults — it was improbable, and had no moral. Coleridge owned the improbability, but replied to the other stricture that it had too much moral, that it ought to have had no more than a story in the ' Arabian Nights.' Indeed, the moral, which would apparently be that people who sympathise with a man who shoots an albatross will die in prolonged torture of thirst, is open to obvious objections. Coleridge's poetical impulse died early ; perhaps, as De Qnincey said, it was killed by the opium ; or as Coleridge said himself, that his afflictions had suspended what nature gave him at his birth, His shaping spirit of imagination. So that his only plan was From his own nature all the natural man, By abstruse research to st^l, and partly, too, I should guess, for the reason that this strange mystic world in which he was at home, was so remote from all ordinary experience that it failed even to provide an efficient symbolism for his deepest thoughts, and could only be accessible in the singular glow and fervour of youthful inspiration. The domestic anxieties, the pains of ill-health, the depression produced by opium, were a heavy clog upon an imagination which should try to soar into vast aerial regions. But it may be doubtful whether this peculiar vein of imagination, emptied in the ' Ancient Mariner ' and ' Christabel,' could in any case have been worked much further. At any rate, Coleridge, as his imaginative impulse flagged, passed into the reflective stage ; and, as was natural, his mind dwelt much upon those principles of art which he had already discussed with Wordsworth in his creative period. In saying that Coleridge was primarily a poet I did not mean to intimate that he was not also a subtle dialectician. There is no real incompatibility between the two faculties. A poetic literature which includes Shakespeare in the past and Mr. Browning in the present is of itself a sufficient proof that the keenest and most active logical faculty may be combined with the truest poetical imagination. Coleridge's peculiar service to English criticism consisted, indeed, in great measure, in a clear appreciation of the true relation between the faculties, a relation, I think, which he never quite managed to express clearly. Poetry, as he says, 246 Mr. Leslie Steiyhen [March 9, is properly opposed not to prose but to science. Its aim, he infers, is not to establish truth but to communicate pleasure. The poet presents us with the concrete symbol ; the man of science endeavours to analyse and abstract the laws embodied. Shakespeare was certainly not a psychologist in the sense in which Professor Bain is a j)sycholo- gist. He does not state what are our ultimate faculties, or how they act and react, and determine our conduct ; but, so far as he creates typical characters, he gives concrete psychology, or presents the problems upon which psychology has to operate. Therefore, if poetry, as Coleridge says after Milton, should be simple, sensuous, passionate, instead of systematic, abstract, and emotionless, like speculative reasoning, it is not to be inferred that the poet should be positively unphilosophical, nor is he the better, as some recent critics appear to have discovered, for merely appealing to the senses as being without thoughts, or, in simpler words, a mere animal. The loftiest poet and the loftiest philosopher deal with the same subject-matter, the great problems of the world and of human life, though one presents the symbolism and the other unravels the logical connection of the abstract conccj^tions. Coleridge, having practised, proceeded to preach. That a poet should also be a good critic is no more surprising than that any man should speak well on the art of which he is master. Our best critics of poetry, at least, from Dryden to Mr. Matthew Arnold, have been (to invert a famous maxim) poets who have succeeded. Coleridge's specific merit was not, as I think, that he laid down any scientific theory. I don't believe that any such theory has as yet any existence except in embryo. He was something almost unique in this as in his poetry, first because his criticism (so far as it was really excellent) was the criticism of love, the criticism of a man who combined the first simple impulse of admiration with the power of explaining why he admired ; and secondly, and as a result, because he placed himself at the right point of view ; because, to put it briefly, he was the first great writer who criticised poetry as poetry, and not as science. The preceding generation had asked, as Mrs. Barbauld asked: What is the moral? Has Othello a moral catastrophe ? What does ' Paradise Lost ' prove ? Are the principles of Pope's ' Essay on Man ' philo- soi^hical, or is Goldsmith's 'Deserted Village' a sound piece of political economy ? The reply embodied in Coleridge's admirable criticisms, especially of Shakespeare, was that this implied a total misconception of the relations of poetry to philosoj^hy. The " moral " of a poem is not this or that proposition tagged to it or deducible from it, moral or otherwise; but the total effect of the stimulus to the imagination and affections, or what Coleridge would call its dynamic effect. That will, no doubt, depend partly upon the philosophy assumed in it; but has no common ground with the merits of a demonstration in Euclid or Spinoza. It is this adoption of a really new method, which makes us feel when we compare Coleridge, not only with the critics of a past generation, but even with very able and 1888.] on S. T. Coleridge. 247 acute wi-iters such as Jeflfrey or Hazlitt, who were his contemporaries, that we are in a freer and hirger atmosphere, and are in contact with deeper principles. It raises another question, for it leads to Cole- ridge's most conscious aim. Nothing is easier than to put the proper label on a poet — to call him " romantic," or " classical," and so forth ; and then, if he has a predecessor of like principles, to explain him by the likeness, and if he represents a change of principles, to make the change explain itself by calling it a reaction. The method is delight- fully simple, and I can use the words as easily as my neighbours. The only thing I find difficult is to look wise when I use them, or to fancy that I give an explanation because I have adopted a classification. Coleridge, both in poetry and philosophy, conceived himself to be one of the leaders of such a reaction. He proposed to abolish the wicked, mechanical, infidel, prosaic eighteenth century and go back to the seventeenth. I do not believe in the possibility or the desirability of any such reaction. I prefer my own grandfathers to tlieir grand- fathers, and myself — including you and me — to my grandfathers. I am quite sure that, if I did not, I could not make time run backwards. We are far enough off to be just to the maligned eighteenth century, and to keep all our uncharitablcness for our contemporaries — it may do them some good. I would never abuse the century which loved common sense and freedom of speech, and hated humbug and mystery ; the century in which first sprang to life most of the social and intellectual movements which are still the best hope of our own ; in which science and history and invention first took their modern shape ; the century of David Hume, and Adam Smith, and Gibbon, and Burke, and Johnson, and Fielding, and many old friends to whom I aver incalculable gratitude ; but I admit that, like other centuries, it had its faults. It was, no doubt, unpoetical at its close — almost as unpoetical as the latter half of the nineteenth ; and somehow it had fallen into that queer blunder of judging poetry by the canons of science. The old symbolism of an earlier generation had faded, and for Pagan or Chiistian imagery we had frigid personifications, such even as Coleriflge quotes from some prize poem : " Inoculation, heavenly maid ! " a deity who ould be only adored in a rhymed medical treatise. And Coleridcfe's charge against the philosophy of the time was really identical with his charge against the poetry. Poetry, without the mystic or spiritual element, meant Darwin's "Botanic Garden"— an ice-palace, as he called it, a heap of fine phrases and sham personifications. Take the same element from theology, and you have Paley's ' Evidences ' ; from morals, and the residuum is Bentham's utilitarianism. Coleridge's nomenclature expressed this in a fashion. He was fond of saying that all men were born Aristotelians or Platonists : Platonists, if, in his favourite distinction, the reason and the imagination dominated in them, and Aristotelians if they had only the understanding, the almost vulpine cunning, which was shared even by the lower animals, which meant prudence in morality, reliance upon mere external evidence in 248 Mr. Leslie Stephen [Marcli 9, theology, and pure expediency in politics. How the Aristotelians had come to rule the world ever since the opening of the eighteenth century is a question which, so far as I know, he never answered. But the effect of their dominion was equally to dethrone reason as to asj)hyxiate imagination. The two were allies, if not an incarnation of the same faculty. Inversely the Benthamites, till Mill was con- verted by Wordsworth, regarded poetry as equivalent to mere tintinnabulation and lying, or, as Carlyle's friend put it, the *' pro- dooction of a rude age." It was as much in his character of poet as of philosopher, thnt Coleridge hated Political Economy, the favourite science of the Benthamites ; for, according to him, it was an illustra- tion of their destructive method. The economist deals with mere barren abstractions, and then misapx3lies them to the concrete organism, the life of which, according to the common metaphor, has been destroyed by his dissecting knife. Coleridge goes too far in speaking as if analysis were in itself a mischievous instead of an important process, much as Wordsworth thought that every man of science was ready to botanise on his mother's grave. But, on the other hand, the clear conviction that a society could only be explained as an organic and continuous whole enables him to point out very distinctly the limits of the opjiosite school. One indication of this contrast may be found in Colerirlge's theory of Church and State. It is curious that Mill, in his ( ssay upon Coleridge, esj^ccially admires him for taking into account the historical element in which Bentham was deficient. It is curious because it is remarkable that the leader of a school which boasted specially of resting upon exj)erience, should admit that it was weak precisely in not appreciating the historical method on which surely experience should be founded. It seems almost as if the antagonists had changed weapons, like the duellists in Hainlef. The a priori thinker rests upon experience, and the empiricist upon a really a priori method. The ambiguity indicates Coleridge's peculiar position towards the opposite school. He regards society as an organism, a something which has grown through long centuries, and therefore to be studied in its vital principle, not to be analysed into a mere mechanism for distributing certain lumps of happiness. In doing so he was saying what had been said by Burke, whoso wisdom he fully apj)reciated and whose real consistency he recognised. To my mind, indeed, Burke as a political j)hilosopher was far greater than Coleridge. But Burke hated the metaphysics in which Coleridge delighted, and therefore with him we seem at best to come upon blank prejudice, or pre- scription, as the ultimate ground of political science. Coleridge feels the necessity of connecting his organic principles with some genuine philosophical principle, and Mill admits that Conservatism in his treatment was something very superior to the mere brute prejudice to which Eldon and Castlereagh appealed, and which was used as a bludgeon by The Quarterly Beview. Unluckily it is here, too, that we find the weakness of Coleridge's character. He tried 1888.] on S. T. Coleridge. 249 to put together his views at a time when his mind had been hope- lessly enervated ; when he could guess and beat about a principle, but could never get it fairly stated or see its full bearings. He is struggling for utterance, still clinging to the belief that he can elaborate a system, but never getting beyond prolegomena and fruitful hints. He says that to study politics with benefit we must try to elaborate the " idea " of Church and State, and the " idea," as he explains, is identical with what scientific people call a law. But how the law or laws of an organism are to be determined by some transcendental principle overruling and independent of ex- periences, is just the point which remains inexplicable. He seems to appreciate what we now call the historic method. He uses the sacred phrase 'evolution,' which is simply the general formula of which the historic method is a special application. But we find that by evolution he means some strange process suggestive of his old mystical employment, and even at times talks of heptads and pentads and the " adorable tetractys," which is the same with the Trinity; and connects chemical laws of oxygen and hydrogen gas with the logical formulfe about prothesis, and antithesis, and meso- thesis. To state the theory of evolution in verifiable and scientific terms was reserved for Darwin ; when we meet it in Coleridge we seem to be going back to Pythagoras ; and yet it is the same thought which is struggling for an utterance in singular and bewildering terms, and moreover it was just the the®ry which Mill required. But, to come to a conclusion, though I cannot think that Cole- ridge ever worked with his mind clear, or was, indeed, capable of the necessary concentration and steadiness of thought by which alone philosophical achievements are possible ; though I hold, again, that if he had succeeded he would have found that he was not so much refuting his opponents as supplying a necessary complement to their teaching, I can still believe that he saw more clearly than any of his contemporaries what were the vital issues ; that in his de- tached, and desultory, and inconsistent fashion he was stirring the thoughts which were to occupy his successors ; and that a detailed examination would show in how many directions a certain Coleridgian leaven is working in later fermentations. Besides the able and zealous disciples who acknowledged his leadership, we might find many affinities in Carlyle's masculine if narrow teaching; or again, in a school which diverged in a very opposite direction, for the theory of Church authority sanctioned by the Oxford disciples of Cardinal Newman is, in spite of its different result, closely allied to Coleridge's ; while the modern Hegelians — though they regard him as a superficial dabbler — must admit that he rendered the service (of doubtful value, perhaps) of infecting English thought with the virus of German metaphysics, and will perhaps admit that, in principle, he anticipated some of their most cogent criticisms of the common enemy. Coleridge never constructed a system. If a philosophy, or its creator, is to be judged by the Vol. XII. (No, 82.) s 250 Mr, Leslie StepJien on S. T. Coleridge. [March 9, systematic characters, Coleridge must take a very low place. But when we think what philosophical systems have so far been ; what flimsy and air-built bubbles in the eyes of the next generation ; how often we desire, even in the case of the greatest men, that the one vital idea (there is seldom so much as one !) could be preserved, and the pretentious structure in which it is involved permitted once for all to burst ; we may think that another criterion is admissible ; that a man's work may be judged by the stimulus given to reflection, even if given in so intricate a muddle and such fragmentary utter- ances that its disciples themselves are hopelessly unable to present it in an orderly form. Upon that ground, Coleridge's rank will be a very high one, although, when all is said, the history, both of the man and the thinker, will always be a sad one — the saddest in some sense that we can read, for it is the history of early promise blighted and vast powers all but running hopelessly to waste. [L. S.] 1888.] Mr. John Murray on Coral Beefs, dc. 251 WEEKLY EVENING MEETING, Friday, March 16, 1888. William Huggins, Esq. D.C.L. LL.D. F.R.S. Vice-President, in the Chair. John Murray, Esq. Structure, Origin, and Distribution of Coral Beefs and Islands. The picturesque beauty of the coral atoll, seated 'mid a waste of troubled waters, with its circlet of living green, its quiet, jDlacid lagoon, and its marvellous submarine zoological gardens, has long been celebrated in the descriptions of voyagers to troj)ical seas. The attempt to arrive at a correct explanation of the general and charac- teristic form and features of these reefs and islands has, for an equally long period of time, exercised the ingenuity of thoughtful men. Coral reefs are the most gigantic and remarkable organic accu- mulations on the face of the earth. They are met with in certain tropical regions, and are huge masses ,of carbonate of lime, secreted from ocean waters by myriads of marine organisms. While the great bulk of the reef consists of dead corals, skeletons and shells, the outer surface is clothed with a living mantle of plants and animals. This is especially the case on the outer and seaward face of the reef, where there are, at all times, myriads upon myriads of outstretched and hungry mouths, and not the least interesting questions connected with a coral reef are those relating to how these hungry mouths are satisfied. It is to the power of these organisms of secreting carbonate of lime from sea water — building up and out generation after generation on their dead selves — that the coral reef owes its origin. So wonder- ful and unique is the result, tbat combination for a definite end has sometimes been attributed to these reef-builders. There is, however, another process ever at work in the ocean, in a sense antagonistic to that of secretion of carbonate of lime by organisms, which has much to do in fashioning the more characteris- tic features of coral reefs. This is the solution of all dead carbonate of lime shells, skeletons, and calcareous debris, wherever these are exposed to the action of sea water. As soon as life loses its hold on the coral structures, and wherever these dead carbonate of lime remains are unprotected by rapid accumulation, they are silently, surely, and steadily removed in solution. This appears to be one of the best established oceanographical facts, and any theories concern- ing the general economy of the ocean which fail to take account of s 2 252 Mr. John Murray [March 16, this universal agency are most likely to be at fault. We know something about the rate of solution, probably more than we do about the rate of growth and secretion of carbonate of lime by the coral polyps. It has been shown that the rate of solution varies with temperature, with pressure, and with the amount of carbonic acid present in the water. It is on the i)lay of these two opposing forces — the one vital and the other chemical — and their varying activity in different regions and under different circumstances, that we rely for the explanation of many oceanographical phenomena, esjiecially many of those connected with oceanic deposits and coral reefs. In some regions there may be more growth, secretion and deposition of shell and coral materials than solution by sea water, and then there results the formation of coral reefs and vast calcareous deposits at the bottom of the ocean. There may be an almost exact balance between these processes. And again, there may be more solution than secretion, as, for instance, in the red clay areas, which occupy the deepest parts of the ocean, and in some coral reef lagoons. "What is the nature of the foundations of these coral islands, surrounded as they sometimes are by an ocean miles in depth ? Why have some elongated reefs no lagoons? Why have most of the lagoons of the smaller atolls been filled up ? Why is the circle of land or reef in the perfect atolls only, at most, a few hundred yards in diameter ? What is the origin of the lagoon ? What relation exists between the depth of the lagoon, its area, and the depth of the water beyond the outer reef? How has the dry land of these islands been formed, provided with a soil, a fauna and a flora ? These appear to be the chief questions that demand an answer from any theory of coral island formation. These coral formations are essentially structures belonging to the gre'at oceans and ocean basins. They are dots of land within the oceanic areas that might be compared or contrasted with tlie small salt lakes which are scattered over the surface of the continen- tal lands. A rapid survey of some of the more general phenomena of the great oceans may, then, lead to a better appreciation of the problems connected with coral reefs. The great ocean basins occupy over two-thirds of the earth's surface, and have a mean depth of over two miles. The central por- tions of these basins, called the abysmal regions, occupy about one- half of the earth's surface, and have a mean depression below the general level of the continents of over three miles. The abysmal regions are vast undulating plains, sometimes rising to less than two miles from the surface of the sea, and again sinking to four and five miles beneath it. Volcanic cones rise singly or in clusters from these great submerged plains. When they shoot above the level of the sea they form single islands, like Ascension and St. Paul's Kocks, or groups, like the Azores, the Sandwich, the Fiji, and the Society Islands. As might have been expected, there are many more of these cones hidden beneath the waves than rise above them. When the 1888.] on Structure, Origin^ and Distribution of Coral Beefs, dc. 253 CTiallenger sounded along the west coast of Africa, there was no suspicion that between her stations she was sailing over submerged cones. Since then, however, the soundings of telegraph ships have correctly mapped out no less than seven of these peaks between the latitude of Lisbon and the island of Teneriffe. The depths on the summits of these vary from 12 to 500 fathoms. On one of them, at 400 fathoms, two species of coral ( Lo_phoheIia jjrolifera and AmjpJiiheUa oculafa) were growing luxuriantly. Throughout the ocean basins about 300 such submarine cones, rising from great depths up to withiQ depths of from 500 to 10 fathoms from the surface, are already known, or indicated by soundings. All the agencies at work above the lower limit of wave action tend to wear away and level down these cones, and thus to form banks. Graham's Island, thrown up in the Mediterranean in 1831, was 200 feet in height and three miles in circumference, and was washed away in a year or two. The bank left on the spot, at first very shallow, has now 21 feet of water over it. Instances similar to this historical example must often have happened in the great ocean basLQS. Again, the same agencies produce wide banks around vol- canic islands by washing away and spreading out the materials of the softer rocks. Such banks, with depths of less than 60 fathoms, are found extending many miles seawards around some volcanic islands. On the other hand, all the deeply submerged summits are con- tinually being built up to the lower limit of wave action by the accu- mulation of the remains of animals which live on them and by the fall of shells upon them from the sui'face waters. In the Solomon Islands, Dr. Brougham Guppy has shown that there are upraised coral islands with central volcanic cones covered with thick layers of marine deposits ; Christmas Island in the Indian Ocean is another instance, and similar deposits must now be forming over hundreds of submerged mountains. In this way are foundations prepared for the true reef-building species, which only flourish in the shallower depths. The bulk of the water of the ocean has a very low temperature : it is ice-cold at the bottom, even under the equator, but on the surface withia the tropics, there is a relatively thin film of warm water, with a temperature of from 70" to 84^ Fahr. This film of warm water is much deeper towards the western parts of the Atlantic and Pacific than it is in the eastern, the reason for this being that the trade winds, which blow contiaually from the east, carry all the warm surface water to the westward, and draw up cold water from beneath along the western shores of Africa and America to supply the place of that driven westward at the surface. Consequently, there is, at times, a very low temperature, and a great annual range of tempe- rature, along these western shores. This is more clearly shown by the temperatures at 50 and 100 fathoms than by those at the sur- face. There are no coral reefe along the western shores of Africa and 254 Mr. John Mitrraij [March 16, Soutli America, a circumstance evidently connected with the low temperature, wide range, and, more directly, with the food supply, consequent on these conditions. It appears to be a confirmation of this view that, on the eastern shores of Africa, about Cape Gardafui, from off which the south-west monsoon blows for several months in the year, cold water is also drawn to the surface, and there, likewise, are no coral reefs, though they flourish to the north and south of this region. Coral reefs flourish in mid-ocean and along the eastern shores of the continents, or wherever the coasts are bathed by the warmest and purest currents of water coming directly from the open sea. If we except Bermuda and one or two other outlying reefi?, where the temperature may occasionally fall to 66° Fahr. or 64° Fahr., it may be said that reefs are never found where the surface temperature of the water, at any time of the year, sinks below 70° Fahr., and where the annual range is greater than 12° Fahr. In typical coral reef regions, however, the temperature is higher and the range much less. The food supply of the coral reef is derived from pelagic oceanic organisms, which exist in the greatest variety and abundance in the surface and sub-surface waters of the ocean. These consist of myriads of algrc, rhizopods, infusorians, mcdusjT), annelids, molluscs, crustaceans, ascidians, and fishes. A very large numbgr of these creatures, within the tropics, secrete carbonate of lime from the ocean to form their shells and skeletons, which, falling to the bottom after death, form the vast oceanic deposits known as Pteropod and Globigerina oozes. In falling to the bottom, they carry down some of the organic matter that composed their living bodies, and thus arc the animals which live on the floor of the ocean chiefly supplied with food. Here it may be remarked that the abundance of life at depths of even over two miles is very great. Our small dredges sometimes bring up over sixty species and hundreds of specimens in one haul — of invertebrates and fishes, exclusive of the protozoa. These pelagic organisms oscillate from the surface down to about 80 or 100 fathoms, probably that stratum of the ocean affected by sunlight, and they ax^parently descend further in regions where the stratum of warm water has a greater depth. Many of the forms rise to the surface in the evening and during calms, and sink again in sunlight and during stormy weather. It is in the evening and when it is calm that this swarming life is most vividly forced on the attention by gorgeous phosphorescent displays. The lime-secreting organisms, like Cocco- spheres and Ehabdospheres, Foraminifera, Pteropods, and other Molluscs, are much more abundant, both in species and individuals, in the warmest and saltest waters than elsewhere. I have estimated, from tow-net experiments, that at least 16 tons of carbonate of lime, in the form of these shells, exist in a mass of the ocean, in coral reef regions, one mile square by 100 fathoms in depth. If we take this estimate, which I consider much below the reality, and suppose 1888.] on Structure, Origin, and Distribution of Coral Beefs, dc. 255 one-sixteenth of these organisms to die and fall to the bottom each day, then they would take between 400 and 500 years to form a deposit one inch in thickness. I give this calculation more to indicate a method than to give even the roughest approximation to a rate of accumulation of deposits. The experiments were too few to warrant any definite deductions. The great oceanic currents moving westward at the rate of several miles an hour, bear these shoals of pelagic organisms on to the face of the reef, where millions of greedy mouths are ready and eager to receive them. The corals and other organisms situated on the outer and windward side of the reef receive the first and best supply ; they are thus endowed with a greater amount of energy, and grow faster and more luxuriantly there than on other portions of the reef; the depth at which there is the most constant supply of this food is several fathoms beneath the surface, and there too the corals are found in most vigorous growth. It is only a relatively small quantity of this pelagic food that enters the lagoon, the corals that there struggle on in patches being largely supplied with the means of existence from the larvae of reef-building animals. So many observations were made during the Challenger Expedi- tion on the pelagic fauna inside and outside reefs that there is little, if any, doubt in my mind that the food supply is a most important factor in relation to the growth of corals in the different portions of a reef. Actual observations were made 'on the feeding of corals at a good many places, as well as numerous observations on the stomach contents. These observations have been confirmed by Alexander It is not possible to state in what form the carbonate of lime that is secreted in such enormous quantities by marine organisms exists in oceanic waters. The following table shows the average composition of sea-water salts, the acids and bases being combined in the way usually adopted by chemists. Average Composition of Sea Salt. Chloride of sodium 77 ' 758 Chloride of magnesium 10 • 878 Sulphate of magnesium 4 • 737 Sulphate of lime 3*600 Sulphate of potash 2*465 Bromide of magnesium 0 • 217 Carbonate of lime 0 • 345 100*000 In the actual ocean water there are probably traces of every known element, and it is impossible to say what is the precise amount of the respective chlorides, sulphates, and carbonates'^present. Theoretically, every base may be combined with every acid, and the whole solution 256 Mr. John Murray [March 16, must be in a continual state of flux as to its internal composition. While the quantity of sea salts in a given volume of water varies with position, yet it has been shown by hundreds of analyses that the actual ratio of acids and bases — that is, the ratio of the constituents of sea salts — is constant in waters from all regions and depths, with one very significant excei)tion — that of lime — which is present in slightly greater proportion in deep water. The total amount of calcium in a cubic mile of sea water is esti- mated at nearly 2,000,000 tons. The amount of the same element present in a cubic mile of river water is nearly 150,000 tons. At the rate at which rivers carry down water from the land it is estimated that it would take 680,000 years to pour into the ocean an amount of calcium equal to that now held by the ocean in solution. The amount of calcium existing in the 40,000,000 square miles of the typical calcareous deposits of the ocean exceeds, however, that at present held in solution if we merely t^ke them to have an average thickness of 30 feet, and from this calculation we might say that, if the secretion and solution of lime in the other regions of the ocean be exactly balanced, and the calcium in the ocean remain always constant, those calcareous deposits of the thickness indicated would require between 600,000 and 700,000 years to accumulate. There is good evidence, however, that the rate of accumulation is much more raj^id in some positions. The lime thus carried down to the sea is originally derived from the decomposition of anhydrous minerals, and comes from the land in the form of carbonate, phosphate, and suljDhate of lime — the carbonate being in the greatest abundance in river water. On the other hand, the sulphate of lime very greatly predominates in sea water, the carbonates being present in small quantity. We are not in a position to say whether or not the coral polyps take the whole of the material for their skeletons from the carbonates, as is generally believed, or indeed to say what changes take place during the progress of secretion by organisms. In the greatest depths of the Pacific coral seas there is striking evidence of the solvent power of ocean water. Our dredges bring up from a depth of three or four miles over a hundred ear-bones of whales and remnants of the dense Ziphioid beaks, but all the larger and more areolar bones of these immense animals have been almost en- tirely removed by solution. In a single haul there may also be many hundreds of sharks' teeth, some of them larger than the fossil Carcha- rodon teeth, but all that remains of them is the hard dentine. None of the numerous calcareous surface shells reach the bottom, although they are quite as abundant over the red clay areas as over those shallower areas where they form Globigerina and Pteropod dej)osits. In consequence of the small amount of detrital material reaching these abysmal areas distant from continents, cosmic metallic spherules, manganese nodules, highly altered volcanic fragments, and zeolitic 1888.] on Structure^ Origin, and Distribution of Coral Beefs^ dc, 257 minerals, are there fonnd in great numbers. Almost all these things are found occasionally in the other regions of the ocean's bed, but their presence is generally masked by the accumulation of other matters. In some regions Radiolarian and Diatom remains are found in the greatest depths, and they too are subject to the solvent power of sea water, but to a much less extent than carbonate of lime shells. As we ascend to shallower waters, a few of the thicker shelled specimens are met with at first, with lesser depths the carbonate of lime shells increase in number, until in the shallower deposits the remains of Pteropods, Heteropods, and the most delicate larval shells are present in the deposit at the bottom. This gradation in the appearance of the shells can be well seen in a series of soundings at different depths around a volcanic cone, such as has been described as forming the base of a coral atoll. There is no known way of account- ing for this vertical distribution of these dead shells except by admitting that they have been dissolved away in sinking through the deeper strata of water, or shortly after reaching the bottom ; indeed, an examination of the shells themselves almost sliows the process in operation. It is rare to find any trace of fish bones in deposits other than the otoliths. These considerations, as well as numerous experiments in the laboratory, show that everywhere in the ocean dead carbonate of lime structures slowly disappear wherever they are exposed to the action of sea water, and in investigating the evolution of the general features of coral reefs it is as necessary to take cognisance of this fact as of the secretion of carbonate of lime by organisms. The first stage, then, in the history of a coral island is the pre- paration of a suitable foundation on submerged volcanic cones, or along the shores of a volcanic island, or the borders of a continent. In the case of the atoll the cone may have been reduced below the level of the sea by the waves and atmospheric influences, or built up to the lower limit of breaker action by the vast accumulation of organisms on its summit, A time comes, however, should the peak be situated in a region where the temperature is sufiiciently high, and the surface currents contain a suitable quality of food, that the reef-builders fix them- selves on the bank. The massive structure which they secrete from ocean water enables them to build up and maintain their position in the very face of ocean currents, of breakers, of the overwhelming and outrageous sea.* " Coral" with the sailor or marine surveyor is usually any carbonate * Dr. Brougham Guppy says, " History can afford us no clue to the first appearance or tlie age of reefs ; yet in the mytlis of the Pacific Islanders we find that the savage inhabitants of these regions regard the history of a coral atoll aa commencing with the submerged shoal, which througli the agency of God-like heroes is brought up by their fish-hooks to the surface." — Fajjer, Vict. Inst. 258 Mr. John 3Iurray [Marcli 16, of lime shell or skeleton or their broken-down parts. " Coral " is used by the naturalist in a much more restricted sense ; he limits the term to animals classed as Madrepores, Hydrocorallines, and Alcyo- narians. The animals belonging to the first two of these orders comprise those included under the vague term of reef corals. Be- sides these, however, very many other classes of animals contribute to the building up of coral reefs and islands — such are Foraminifera, Sponges, Polyzoa, Annelids, Echinoderms, and Calcareous Algae. The relative proportions of these different organisms in a reef vary with the region, with the depth, and with the temperature, but members of what are known under the term of reef corals appear always to predominate. The animals of the true reef-building species resemble the common sea anemones in structure and size ; the individual polyps may vary from the eighth of an inch in diameter to over a foot. Some of the structures built by colonies may exceed 20 feet in diameter. There may be great variety in the appearance of submerged reefs as they rise from banks of a different nature, form, and extent, as, indeed, was pointed out long ago by Chamisso. There may be differences due also to the kinds and abundance of deep-sea animals living on such banks, as well as differences due to currents, tempera- ture, and other meteorological conditions. From the very first the plantations situated on the outer edge will have the advantage, from the more abundant supply of food and the absence of sand in the water, which last more or less injuriously affects those placed towards the interior. Chamisso attributed the existence of the lagoon to the more vigorous growth of the peri- pherally situated corals of a reef, as compared with those placed towards the middle, and in this he was to a large extent right, but the symmetrical form of the completed atoll is chiefly due to the solution of the dead carbonate of lime structures. The Great Chagos Bank illustrates the irregular way in which such a large bank of coral plantations approaches the surface. When these, however, reach the surface, they assume slowly a more regular outline, those on the outer edge coalesce, and ultimately form a complete ring of coral reef, and the lagoon becomes gradually cleared of its coral patches or islands, for as the atoll becomes more perfect, the con- ditions of life within the lagoon become less and less favourable, and a larger quantity of dead coral is removed in solution. The coral atoll varies greatly in size and form : it is usually more or less circular, and may be one or over fifty miles in diameter. The breakers spend their fury on the outer edge, and produce what is known as the broad shore platform ; but within, trees descend to the very shore of the lagoon, where there is quiet water, and a ship may often enter on the lee side of the atoll and find safe anchorage. In this connection it is important to bear in mind the relation which exists between the periphery and the superficial area of the lagoon in atolls of different sizes. If the coral plantations which rise 1888.] on Structure, Origin, and Distribution of Coral Beefs, &c. 259 from the top of a submerged mounta'n have an area of one square mile, then on reaching the surface of the waves there will be a shallow depression in the centre owing to the more rapid growth of the outer edge. Such an atoll will have, if it be a square, four miles of outer reef for the supply of coral sand and other debris, and these being washed and blown into the one square mile of shallow lagoon it is likely to become filled up, the result being a small island with dry lagoon in which may be found deposits of sulphate of lime, magnesian and phosphatic rocks, and guano — all these testifying to the great age of the island and absence of subsidence in the region. It is only atolls with a diameter of less than two miles that thus become filled up. In other and larger plantations, rising from a more extensive bank, the conditions are very different. In this larger atoll — say four miles square — there is now only one mile of outer reef to each square mile of lagoon, instead of four miles of outer reef to the one square mile of lagoon in the smaller atoll. Only one-fourth of the detrital matter and food enters the larger lagoon, from the outside, per square mile of lagoon, and hence there is proportionally less living coral ; the solvent agencies predominate and the lagoon is widened and deepened. Growing seawards on the outer face and dissolving away in the lagoon, the whole expands after the manner of a fairy ring, and the ribbon of reef or land can never in consequence increase beyond a half or three-quarters of a mile in width, it being usually much less. ' Atolls may occur far away from any other land, but it more frequently happens that they are arranged in linear groups, in this respect resembling volcanic islands. Extensive banks may be crowded with small atolls, like the Northern Maldives ; or a bank may be occupied by one great and perfect atoll 20 to 40 miles in diameter, like some of the Southern Maldives and the Paumotus. In some instances the large atolls aj^pear to have resulted from the growth and coalescence of the smaller marginal atolls ; esi)ecially does this seem to have been the case with the large Southern Maldives. The outer slopes vary greatly in different reefs, and in different parts of the same reef. When there is deep water beyond, the reef very often extends out with a gentle slope to a depth of 25 to 40 fathoms, and is studded with living coral, the bosses and knobs becoming larger in the deeper water farthest from the reef, where there are great overhanging cliffs, which eventually fall away by their own weight and form a talus on which the reef may proceed further outwards. Occasionally there is a very steep descent almost at once from the outer edge. Thus the deeper the water beyond, the more slowly will the reef extend seawards. In reefs with a very gentle slope outside, the corals are frequently overhanging at depths of six or seven fathoms, for in these instances the lower part of the sea-face of the reef is rendered unsuitable for vigorous growth, in consequence of the sand which is carried in by waves coming over the comparatively shallow depths outside. 260 Mr. John Murray [March 16, As has been stated, the lagoon in many of the smallest atolls has been filled up, but this never ajDpears to happen in atolls with a diameter of over two miles unless there be distinct evidence of ui)heaval. In perfectly formed atolls, that is, those in which the reefs are nearly continuous throughout, the deepest water is found towards the centre of the lagoon, and there is a relation between this depth and the depth of water be3^ond the outside reefs. In North and South Minerva reefs, in the South Pacific, where the outside depths are very great, there are depths down to 17 fathoms in the lagoons, which are apparently clear of coral heads. Here we may suppose that the central parts of the lagoon have for a long time been exposed to the solvent action of sea-water, owing to the slow lateral growth of the reef as a whole. In the same regions the Elizabeth and Middleton reefs, which are about the same size, have only four or five fathoms within the lagoons, and the depths outside the reefs are at the distance of a mile mostly within the 100 fathom line, and sometimes less than 50 fathoms. There are also many coral heads within the lagoons. Here we may suppose the atolls to be more recent and to have extended more rapidly than in the case of the Minerva reefs. If the depths beyond the reefs be taken into con- sideration, then there is usually a direct relation between the depth of the lagoon and its diameter. The greatest depths, even in the largest atolls, do not exceed 50, or at most 60, fathoms ; they are usually much less. In atolls which are deeply submerged, or have not yet reached the surface, which have wide and dcej) ojDcnings into the lagoon-like spaces, this relation may not exist. In these instances the secretion and deposition of carbonate of lime may be in excess of solution in all parts of the lagoon. It is only when the atoll reaches the surface, becomes more perfect, and its lagoon waters consequently less favourable to growth, that the solution of the dead corals and calcareous debris exceeds any secretion and deposition that may take place throughout the whole extent of the lagoon ; it is then widened and deepened, and formed into a more or less perfect cup-like depression. The whole of a coral reef is permeated with sea-water like a sponge ; as this water is but slowly changed in the interior parts it becomes saturated, and a deposition of crystalline carbonate of lime frequently takes place among the interstices of the corals and coral debris. In consequence of the solution of coral debris and the re- deposited lime occupying less space, large cavities are formed, and this process often results in local depression in some islands, as, for instance, in Bermuda. At many points on a reef where evaporation takes place there is a deposition of amorphous carbonate of lime cementing the whole reef materials into a compact conglomerate-like rock. The fragments of the various organisms broken off from the outer edge during gales or storms are piled up on the upper siu'face of the reef, and eventually ground into sand, the result being the formation 1888.] on Structure, Origin, and Distribution of Coral Beefs, &c. 261 of a sandy cay or slioal at some distance back from the outer edge of the reef — the first stage in the formation of dry Lmd. The fragments of pumice thrown up into the ocean during far- distant submarine eruptions, or washed down from volcanic lands, are at all times to be found floating about on the surface of the sea, and these being cast upon the newly formed islet produce by their disintegration the clayey materials for the formation of a soil — the red earth of coral islands. Just within the shore platform these pumice fragments are found in a fresh condition, but as the lagoon is approached they disappear, the soil becomes deeper, and the most luxuriant vegetation and largest trees are found close to the edge of the inner waters. The land is seldom continuous around the atoll ; it occurs usually in patches. The water passes over the shallow spaces between the islets and through the deeper lagoon entrances, these last being kept open by the strong sand-bearing currents which pass at each tide. The few species of plants and animals which inhabit these coral islands have been drifted to the new island like the pumice, or carried, many of them may be, by birds ; lastly, savage and civilised man finds there a home. There is no essential difference between the reefs forming fringing and barrier reefs, and those which are known as atolls. In the former case the corals have commenced to grow close to the shore, and as they grow outward, a small boat passage, and then a ship channel, is carved out between the reef and the shore by tidal scour and the solvent action of the water on the dead parts of the reef : thus the fringing reef may be converted into a barrier reef. In some instances the corals find a suitable foundation on the banks that surround islands and front continental lands, it may be, at a great distance from the coast, and when they reach the surface they form a distant barrier which proceeds seawards, ultimately on a talus made up of materials torn from its seaward face. If the foregoing considerations be just and tenable, then it would aj)pear that all the characteristic features of coral reefs can be pro- duced, alike in stationary areas or in areas of slow elevation and sub- sidence, by processes continually at work in the ocean at the present time. Slow elevation or subsidence would only modify in a minor way a typical coral atoll or barrier reef, but subsidence in past times cannot be regarded as the cause of the leading characteristics of coral reefs. There are abundant evidences of elevation in coral reef regions in recent times, but no direct evidence of subsidence. If it has been shown that atoll and barrier reefs can be formed without subsidence, then it is most unlikely that their presence in any way indicates regions of the earth's surface where there have been wide, general, and slow depressions. According to Mr. Darwin's theory, which has been almost uni- versally accepted during the past half century, the corals commence to grow close to the shore of an island or continent : as the land 262 Mr. John Murray on Coral Beefs, dec. [March 16, slowly sinks the corals meanwhile grow upwards to the surface of the sea, and a water space — the lagoon channel — is formed between the shore of the island and the encircling reef, the fringing being thus converted into a barrier reef. Eventually the central island sinks altogether from sight and the barrier reef is converted into an atoll, the lagoon marking the place where the volcanic or other land once existed. Encircling reefs and atolls are represented as becoming smaller and smaller as the sinking goes on, and the final stage of the atoll is a small coral islet, less than two miles in diameter, with the lagoon filled up and covered with deposits of sea-salts and guano. It is at once evident that the views now advocated are in almost all respects the reverse of those demanded by Mr. Darwin's theory. The recent deep-sea investigations do not appear in any way to support the view that large or small islands once filled the spaces now occupied by the lagoon waters, and that the reefs show approxi- mately the position of the shores of a subsided island. The struc- ture of the upraised coral islands, so far as yet examined, appears to lend no support to the Darwinian theory of formation. When we remember that the great growing surface of existing reefs is the sea- ward face from the sea surface down to twenty or forty fathoms, that large quantities of coral debris must be annually removed from lagoons in suspension and solution, that reefs expand laterally and remain always but a few hundred yards in width, that the lagoons of finished atolls are deepest in the centre, and are relatively shallow compared with the depth off the outer reefs, then it seems impossible with our present knowledge to admit that atolls or barrier reefs have ever been developed after the manner indicated by Mr. Darwin's simple and beautiful theory of coral reefs. [J. M.] WEEKLY EVENING MEETING, Friday, March 23, 1888. William Huggins, Esq. D.C.L. LL.D. F.E.S. Vice-President, in the Chair. Sir Frederick Bramwell, D.C.L. F.E.S. Hon. Sec. and V.P. BJ. A Lecture with, — and without, — jyoint. [The discourse mainly consisted of a demonstration of the serious inconveniences attending the adoption in ordinary life of the Decimal and Metrical Systems.] (Abstract deferred.) 1888.] General Monthly Meeting. 263 GENERAL MONTHLY MEETING, Monday, April 2, 1888. Sir James Criohton Browne, M.D. LL.D. F.R.S. Manager, in the Cliair. William Arthur Brailey, M.D. M.A. M.K.C.S. Thomas E. Dallmeyer, Esq. Samuel cle Lissa, Esq. Walter Gilbey, Esq. Colonel Alexander Charles Hamilton, R.E. Robert Moon, Esq. Fitzpatrick Praed, Esq. were elected Members of the Royal Institution. The Special Thanks of the Members were returned to His Grace the Duke of Northumberland, E.G. the President, for his present of ' Annals of the House of Percy (1030-1887). By E. B. de Fcnblanque, 2 yoI. 1887 ' ; and to Lieutenant-General Pitt-Rivers, M.JR.I. for his present of ' Excavations' in Cranboine Chase, near Rushmore. Vol. I. 1887.' The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Secretary of State for India — Keport of a Tour in the Panjab and Rajpftt^na in 1883-4. By H. B. W. Garrick (Archseol. Survey of India), 8vo. 1887. The French Government — Topographie Historique du Vieux Paris. Eegion Occidentals de rUniveiejite. Par F. A. Berty et L. M. Tisserand. 4to. et Plan. 1887. Accademia dei Lincei, Reale, Roma — Atti, Serie Quarta : Eendiconti. Vol. III. 2« Semestre, Fasc. 10, 11. 8vo. 1887. Academie des Sciences de VListitut, Paris — Memoires, Tome XLII. 4to. 1883. Memoires presentes par Divers Savants, Tomes XXVII. XXVIII. XXIX. 4to. 1883-7. Receuil de Memoires, etc. relatifs a I'Observation du Passage de Venus sur le Soleil, Tome II. Partie 2 ; Tome III. Parties 1-3. 4to. 1880-5. American Fhilosophical Society — Proceedings, No. 126. 8vo. 1887. Asiatic Society, Royal {China Branch) — Journal, Vol. XXII. Nos. 1, 2. 8vo. 1887. Astronomical Society, Royal — Monthly Notices, Vol. XLVIII. No. 4. 8vo. 1888. Memoirs, Vol. XLIX. Part 1. 4to. 1888. Bankers, Institute o/— Journal, Vol. IX. Part 3. 8vo. 1888. Batavia Observatory — Magnetical and Meteorological Observations, Vol. IX. 1886. 4to. 1887. Rainfall in East Indian Archipelago, 1886. 8vo. 1887. 264: General Monthly Meeting. [April 2, Brituh Association for the Advancement of Science — Report of Meeting at Manchester, 1887. 8vo. 1888. British Architects, Royal Institute o/— Proceedings, 1887-8, Nos. 10, 11. 4to. Chazarain, Dr. (the Author)— hes Courants de la Polarite' dans I'Aimant et dans le Corps Huraaiii. 8vo. 1887. Chemical Society — Journal for jNIarch 1888. 8vo. Churchill, 3Iessrs. J. and A. (the Publishers) — Journal of Laryngology and Rhinology, Vol. II. Nos. 1, 2, 3. 8vo. 1888. Civil Engineers' Institution — IMinutes of Proceedings, Vol. XCI. 8vo. 1887-8. Dawson, George M. Esq. F.G.S. (the Author) — Kwakiool People of Vancouver Island (Trans. Koyal Soc. of Canada). 4to. 1888. Dax : Societe de Borda — Bulletins, 3*^ Serie, Douzieme Annee, Trimestre 3"^. 8vo. 1888. Editors — American Journal of Science for March, 1888. 8vo. Analyst for March, 1888. 8vo. Atheuseum for March, 1888. 4to. Chemical News for March, 1888. 4to. Chemist and Drus^gist for March, 1888. 8vo. Engineer for March, 1888. fol. Engineering for IVIarch, 1888. fol. Horological Journal for March, 1888. Svo. Industries for March, 1888. ful. Iron for Marcli, 1888. 4to. Murray's Magazine for March, 1888. 8vo. Nature for March, 1888. 4to. Revue Scieutifique for March, 1888. 4to. Scientific News for IMarch, 1888. 4to. Telegraphic Journal for March, 1888. Svo. Zoophilist for March, 1888. 4to. Foster, J. Esq. (the Editor) — Alumni Oxonienses : The Members of the University of Oxford, 1715-188(3. Vol.1. Svo. 1888. Florence, Bihlioteca Nazionale Centrale — Bolletino, Num. 52, 53. Svo. 1888. Franklin Institute — Journal, No. 747. Svo. 1888. Geographical Society, Royal — Proceedings, New Series, Vol. X. No. 3. Svo. 1888. Supplementary Papers, Vol. II. Part 2. Svo. 1888. Geological Institute, Imperial, Vienna — Abhandlungen, Band XI. No. 2. fol. 1887. Jahrbuch, Band XXXVII. Heft 2. Svo. 18S8. Verhandlungeu, 1S87. Nos. 9-16. Svo. GeorgofiU, Reale Accademia — Atti, Quarta Serie, Vol. X. Disp. 3, 4. Svo. 1887. Johns Hophins University — American Journal of Philology, Vol. VIII. No. 4. Svo. 1887. Studies in Historical and Political Science, Fifth Series, No. 12. Svo. 1887. University Circular, No. 63. 4to. 1888. Linnean Society— J omna.], No. 162. Svo. 1888. Manchester Geological Society —Transactions, Vol. XIX. Parts 14, 15. Svo. 1888. Manchester Literary and Scientific Society — Memoirs, Vol. X. Third Series. Svo. 1887. Proceedings, Vol. XXV. XXVI. Svo. 1885-7. Medical and Chirurgical Society, i?o;/aZ— Proceedings, No. 17. Svo. 1887. Meteorological Office — Weekly Weather Reports, Vol. IV. Nos. 46-52. Appendix 1-4. Vol. V. Nos. 1-7. 4to. 1887-8. Hourly Readings, 1885, Part 2. 4to. 1888. Monthly Weather Reports, Jan. Feb. 1887. 4to. Ministry of Public Works, i?o)ne— Giornale del Genio Civile, Serie Quinta, Vol. II. No. 1. Svo. And Disegui. fol. 1888. North of England Institute of Mining and Mechanical Engineers — Transactions. Vol. XXXVII. Part 2. Svo. 1888. 1888.] General Monthly Meeting. 265 NortJmmhcrland, His Grace the Duke of, K.G. D.C.L. F.Ii.S. Pres. iJ.Z.— Annals of the House of Percy (1030-1887). By E. B. de Fonblanque. 2 vol. [Privately Printed.] 8vo. 1887. Odontological Society of Great Britain — Transactions, Vol. XX. No. 4. New Series. 8vo. 1888. Fennsylvania Geological Survey — Annual Report, 1886, 2 Parts. 8vo. 1887. Pharmaceutical Society of Great Britain — Journal, March, 1888. 8vo. Photogra])hic Society — Journal, Vol. XII. No. 5. 8vo. 1888. Pitt-Rivers^ Lieut.- Goieral, D.C.L. F.R.S. M.R.I, {the ^w^/ioj-)— Excavations in Cranborne Cliase. near Rushmore, Vol. I. 4to. 1887. [Privately Printed,] Richardson, B. W. M.D. F.R.S. (the Author)— The Asclepiad, Vol. V. No. 17. 8vo. 1888. Royal Society of London — Proceedings, No. 263. 8vo. 1888. Roijal Scottish Society of ^rfs— Transactions, Vol. XII. Part 1. 8vo. 1888. Russell, TJie Hon. RoUo, M.R.I, {the .4 «/^/jor)— National Strategy against Infection. 8vo. 1888. Saxon Society of Sciences, Royal — Philologisch-historische Classe: Berichte. 1887. Nos. 4, 5. 8vo. Matheraatisch-physische Classe : Berichte, 1887. Nos. 1, 2. 8vo. 1888. Societe' Archeologique du Midi le la France — Me'moires, Tome XIV. 2^ Liv. 4to. Toulouse. 1887. Bulletin. Nouvelle Serie, No. 4. 4to. Toulouse, 1887. Society for the Abolition of Vivisection — The Brown Animal Sanatory Institution. 8vo. 1888. Society of ^r^s— Journal, March, 1888. 8vo. St. Bartholomew's Hospital— Beports, Vol. XXIII. 8vo. 1887. St. Petershourq Academie Imp&iales des Sciences — Memoires, Tome XXXV. No. 10. 4to. 1887. Telegraph Engineers, Society of — Journal, No. 70. 8vo. 1888. The British Museum, {Natural History) — Catalogue of Birds, Vol. XII. 8vo. 1888. Catalogue of Fossil Mammalia, Part 5, 8vo. 1887. Guide to the Shell and Starfish Galleries. 8vo. 1887. Tomalin, Lewis R. S. Esq. {the Author) — Essays on Health Culture. By G. Jaeger. 8vo. 1887. Vereins zur Beforderung des Gewerhfleises in Preussen — Verhandlungen, 1888 : Heft, 2. 4to. Velschov), Franz A. Esq. C. E. {the Author) — The Natural Law of relation between Rainfall and Vegetable Life. Svo. 1888. Vol. XIL (No. 82.) 266 Professor Floicer [April 13, WEEKLY EVEXIXG :\IEETIXG, Friday, AprQ 13, ISSS. Edwabd Woods, Esq. M.Iiist.C,E. Tic«-President, in tlie Chair. Pbofessob William HE^-EY Flower, C.B. LL.D. F.K.S. The Pygmy Paces of Meu. It is well known that the nations of antiquity entertained a wide- spread belief in the existence of a race or races of human beings of exceedingly diminutive stature, who dwelt in some of the remote and unexplored regions of the earth. These were called Pygmies^ a word said to be derived from Tn-z/xyj, which means a fist, and also a measure of length, the distance from the elbow to the knuckles of an ordinary- sized man, or rather more than 13 inches. In the opening of the third book of the Iliad, the Trojan hosts are described as coming on with noise and shouting, " like the cranes which flee from the coming of winter and sudden rain, and fly with clamour towards the streams of ocean, bearing slaughter and fate to the Pygmy men, and in early mom oflfer cruel battle," or, as Pope has it — *' So when inclement winters vex the plain, "With piercing frosts, or thick descending rain, To wanner seas the cranes embodied fly. With noise and order throngh the midway sky. To Pygmy nations wourds and d.ath they bring. And 'aU the war descends upon the wing." The combats between the pygmies and the cranes are often alluded to by later classical writers, and are not unfrequently depicted upon Greek vases. In one of these in the Hope collection at Deep- dene, in which the figures are represented with great spirit, the pygmies are dwarfish-looking men with large heads, negro features, and close woolly or frizzly hair. They are armed with lances. Notices of a less poetical and apparently more scientific character of the occurrence of races of very small human beings are met with in Aristotle, Herodotus, Ctesias, Pliny, Pomponius Melo, and others. Aristotle places his pygmies in Africa, near the sources of the Nile, while Ctesias describes a race of dwarfs in the interior of India. The account in Herodotus is so circumstantial, and has such an air of truthfulness about it, especially in connection with recent discoveries, that it is worth quoting in full.* " I did hear, indeed, what I will now relate, from certain natives of Cyr4ne. Once up<>n a time, they said, they were on a visit to the * HexodotTis. Bc-cik II.. 32, Eawlinson's trarislation, p. 47. J 888.] on tie Pygmy Baces of Men. 2G7 oracular shrine of Ammon, when it chanced that, in the course of conversation with Etearchus, the Ammonian king, the talk fell upon the Xile, how that its sources were unknown to all men. Etearchns upon this mentioned that some Xasamonians had once come to his court, and when asked if they could give any information concerning the uninhabited parts of Libya, had told the following tale. (The Xasamonians are a Libyan race who occupy the Syrtes, and a tract of no great size towards the east. ) They said there had grown np among them some wild young men, the sons of certain chiefs, who, when they came to man's estate, indulged in all manner of extrava- gancies, and among other things drew lots for five of their number to go and explore the desert parts of Libya, and try if they could not penetrate fui'ther than any had done previously. The young men therefore dispatched on this errand by their comrades with a plentiful supply of water and provisions, travelled at first through the inhabited region, passing which they came to the wild beast tract, whence they finally entered upon the desert, which they proceeded to cross in a direction from east to west. After journeying for many days over a wide extent of sand, they came at last to a plain where they observed trees growing : approaching them, and seeing fruit on them, they proceeded to gather it. While they were thus engaged, there came upon them some dwarfish men, under the middle height, who seized them and carried them ofi". The Xasamonians could not understand a word of their language, nor had they any acquaintance with the language of the Xasamonians. They wt-re led across extensive marshes, and finally came to a town, where all the men were of the height of their conductors, and black-complexioned. A great river flowed by the town, running from west to east, and containing crocodiles."' It is satisfactory to know that the narrative concludes by saying that these pioneers of African exploration, forerunners of Bruce and Park, of Earth. Livingstone, Speke, Grant, Schweinfurth. Stanley, and the rest, '•' got safe back to their country." Extension of knowledge of the natural products of the earth, and a more critical spirit on the part of authors, led to attempts to account for this belief, and the discovery of races of monkeys — of the doings of which, it must be said, more or less fabulous stories M-ere often reported by travellers — generally sufficed the commentators and naturalists of the last century to explain the origin of the stories of the pygmies. To this view the great authority of Buftbn was extended. Still more recently-acquired information as to the actual condition of the human j^opulation of the globe has, however, led to a revision of the ideas upon the subject, and to more careful and critical researches into the ancient documents. M. de Quatrefages, the emi- nent and veteran Professor of Anthropology at the Huseum d'Histoire Xaturelle of Paris, especially, has carefully examined and collated all the evidence bearing upon the question, and devoted much ingenuity of argument to prove that the two localities in which the ancient authors appear to place their pygmies, the interior of Africa near T 2 268 Professor Flower [April 13, the sources of the Nile, and tho southernmost parts of Asia, and the characters they assign to them, indicate an actual knowledge of the existence of the two groups of small people which still inhabit these regions, the history of which will form the subject of this lecture. The evidence which has convinced M. de Quatrefages, and which, I have no doubt, will sufiBce for those who take pleasure in discovering an underlying truth in all such legends and myths, or in the more grateful task of rehabilitating the veracity of the fathers of literature and history, will be found collected in a very readable form in a little book published last year in the ' Bibliotheque scientifique contemporaine,' called ' Les Pygmees,' to which I refer my hearers for fuller information upon the subject of this discourse, and especially for numerous references to the literature of the subject, which, as the book is accessible to all who wish to pursue it further, I need not give here. It is still, however, to my mind, an open question whether these old stories may not be classed with innumerable others, the offspring of the fet'tile invention of the human brain, the potency of which as an origin of myths has, I think, sometimes been too much underrated. I shall, therefore, now take leave of them, and confine myself to giving you, as far as the brief space of time at my disposal admits, an account of our actual knowledge of the smallest races of men either existing, or, as far as we know% ever having existed on earth, and which may, therefore, taking the word in its current though not literal sense, bo called the " pygmies " of the species. Among the various characters by which the different races of men are distinguished from one another, size is undoubtedly one of con- siderable importance. Not but what in each race there is much in- dividual variation, some persons being taller and some shorter ; yet these variations are, especially in the purer or less mixed races, restricted within certain limits, and there is a general average, both for men and women, which can be ascertained when a sufficient number of accurate measurements have been recorded. That the ])vq- vailing size of a race is a really deeply-seated, inherited character- istic, and depends but little on outward conditions, as abundance of food, climate, &c., is proved by well-know^n facts. The tallest and the shortest races in Eurojie are respectively the Norwegians and the Laj^ps, living in' almost the same region. In Africa, also, the diminu- tive Bushmen and the tallest race of the country, the Kaffirs, are close neighbours. The natives of the Andaman Islands and those of many islands of the equatorial region of the Pacific, in which the conditions are similar, or if anything more favourable to the former, are at opposite ends of the scale of height. Those not accustomed to the difficulties both of making and recording such measurements will scarcely be prepared, however, to learn how meagre, unsatisfactory, and unreliable our knowledge of the stature of most of the races of mankind is at present, although unquestionably it has been consider- ably increased within recent years. We must, however, make use of 1888.] on the Pygmy Races of Men. 269 such material as wo j^ossess, and trust to tlie future correction of errors when better opportunities occur. It is convenient to divide men, according to their height, into three groups — tall, medium, and short ; in Topinard's system,* the first being those the average height (of the men) of which is above 1 • 700 metres (5 feet 7 inches), the last those below 1 • 600 metres (5 feet 3 inches), and the middle division those between the two. In the short division are included certain of the Mongolian or yellow races of Asia, as the Samoyedes, the Ostiaks, the Japanese, the Siamese, and the Annamites ; also the Veddahs of Ceylon and certain of the wild hill- tribes of Southern India. These all range between 1*525 and 1*600 metres — say between 5 feet and 5 feet 3 inches. It is of none of these people that I am going to speak to-day. My j)ygmies are all on a still smaller scale, the average height of the men being iu all cases below 5 feet, in some cases, as we shall see, considerably below. Besides their diminutive size, I may note at the outset that they all have iu a strongly-marked degree the character of the hair dis- tinguished as frizzly — i. e. growing in very fine, close curls, and flattened or elliptical iu section, and therefore, whatever other structural diftercnces they present, they all belong to the same j)rimary branch of the human species as the African negro and the Melanesian of the Western Pacific. I will first direct your attention^ to a group of islands in the Indian Ocean — the Andamans — where we shall find a race in many respects of the greatest possible interest to the anthropologist. These islands are situated in the Bay of Bengal betsveen the lOth and 14th parallels of north latitude, and near the meridian 93° east of Greenwich, aud consist of the Great and Little Andamans. The former is about 140 miles long, and has a breadth nowhere exceeding 20 miles. It is divided by narrow channels into three, called re- spectively North, Middle, and South Andaman, and there are also various smaller islands belonging to the group. Little Andaman is a detached island lying about 28 miles to the south of the main group, about 27 miles in length and 10 to 18 in breadth. Although these islands have been inhabited for a very great length of time by people whose state of culture and customs have undergone little or no change, as proved by the examination of the contents of the old kitchen-middens, or refuse heaps, found in many places in them, and although they lie so near the track of civilisation and commerce, the islands and their inhabitants were practically unknown to the world until so recently as the year 1858. It is true that their existence is mcLtioned by Arabic writers of the ninth century, and again by Marco Polo, aud that in 1788 an attempt was made to establish a penal colony upon them by the East India Company, which was abandoned a few years after ; but the bad repu- * ' ElemeutB d'4uthr()pok)gic G-cuerale.' Paris, 1885, p. 463. 270 Professor Flower [April 13, tation tlie inhabitants had acquired for ferocious and inhospitable treatment of strangers brought by accident to their shores, caused them to be carefully avoided, and no permanent settlement or relations of anything like a friendly character, or likely to afford any useful information as to the character of the islands or the in- habitants, were established. It is fair to mention that this hostility to foreigners, which for long was one of the chief characteristics by which the Andamanese were known to the outer world, found much justification in the cruel exj)eriences they suffered from the mal- practices, especially kidnapping for slavery, of the Chinese and Malay traders who visited the islands in search of heche de mer and edible birds'-nests. It is also to this characteristic that the in- habitants owe so much of their interest to us from a scientific point of view, for we have here the rare case of a population, confined to a very limited space, and isolated for hundreds, perhaps thousands, of years from all contact wdth external influence, their physical characters unmixed by crossing, and their culture, their beliefs, their language entirely their own. In 1857, when the Sepoy mutiny called the attention of the Indian Government to the necessity of a habitation for their numerous convict prisoners, the Andaman Islands wxre again thought of for the purpose. A Commission, consisting of Dr. F. J. Mouat, Dr. G. Playfair, and Lieut. J. A. Heathcote, was sent to the islands to report upon their capabilities for such a jnirpose ; and, acting upon its recommendations, early in the following year the islands were taken possession of in the name of the East India Company by Captain (now General) H. Man, and the British flag hoisted at Port Blair, near the southern end of Great Andaman, which thenceforth became the nucleus of the settlement of invaders, now numbering about 15,000 persons, of whom more than three-fourths are convict prisoners, the rest soldiers, police, and the usual accompaniments of a military station. The effect of this inroad upon the unsophisticated native popula- tion, who, though spread over the whole area of the islands, were far less numerous, may easily be imagined. It is simply deterioration of character, moral and physical decay, and finally extinction. The newly-introduced habits of life, vices, and diseases, are spreading at a fearful rate, and with deadly effect. In this sad history there are, however, two redeeming features which distinguish our occupation of the Andaman s from that of Tasmania, where a similar tragedy was played out during the present century. In the first place, the British Governors and residents appear from the first to have used every effort to obtain for the natives the most careful and considerate treatment, and to alleviate as much as possible the evils which they have unintentionally been the means of inflicting on them. Secondly, most careful records have been preserved of the physical characters, the social customs, the arts, manufactures, traditions, and language of the people while still in their primitive condition. For this most 1888.J on the Pygmy Maces of Men. 271 important work, a work wbich, if not done, would have left a blank in the history of the world which could never have been replaced, we are indebted almost entirely to the scientific enthusiasm of one individual, Mr. Edward Horace Man, who most fortunately happened to be in a j^osition (as Assistant Superintendent of the Islands, and specially in charge of the natives) which enabled him to obtain the required information with facilities which probably no one else could have had, and whose observations ' On the Aboriginal Inhabi- tants of the Andaman Islands,' published by the Anthropological Institute of Great Britain and Ireland, are most valuable, not only for the information they contain, but as correcting the numerous erro- neous and misleading statements circulated regarding these people by previous and less well-informed or less critical authors. The Arab writer of the ninth century previously alluded to, states that " their complexion is frightful, their hair frizzled, their countenance and eyes frightful, their feet very large, and almost a cubit in length, and they go quite naked," while Marco Polo (about 1285) says that " the people arc no better than wild beasts, and I assure you all the men of this island of Angamauain have heads like dogs, and teeth and eyes likewise ; in fact, in the face they are just like big mastiff dogs." These specimens of mediajval anthropology are almost rivalled by the descrijDtions of the customs and moral character of the same people j)ublished as recently as 1862, based chiefly on information obtained from ^ne of the runaway sepoy convicts, and which represent them as among the lowest and most degraded of human beings. The natives of the Andamans are divided into nine distinct tribes, each inhabiting its own district. Eight of these live upon the Great Andaman Islands, and one upon the hitherto almost unexplored Little Andaman. Although each of these tribes possess a distinct dialect, these are all traceable to the same source, and are all in the same stage of develoj)ment. The observations that have been made hitherto relate mostly to the tribe inhabiting the south island, but it does not appear that there is any great variation either in physical characters or manners, customs, and culture among them. With regard to the important character of size, we have more abundant and more accurate information than of most other races. Mr. Man gives the measurements of forty-eight men and forty-one women, making the average of the former 4 feet lOf inches, that of the latter 4 feet 1^ inches, a difference therefore of 3 J inches between the sexes. The tallest man was 5 feet 4 J inches; the shortest 4 feet 6 inches. The tallest woman 4 feet llj inches ; the shortest 4 feet 4 inches. Measurements made upon the living subject are always liable to errors, but it is possible that in so large a series these will compensate each other, and that therefore the averages may be relied upon. My own observations, based upon the measure- ments of the bones alone of as many as twenty-nine skeletons, give smaller averages, viz. 4 feet 8.^ inches for the men, and 4 feet 6 J 272 Professor Fhwer [April 13, inches for the women ; but these, it must be recollected, are cal- culated from the length of the femur, U2)on a ratio which, though usually correct for Europeans, may not hold good in the case of other races.* The hair is fine, and very closely curled ; woolly, as it is generally called, or, rather, frizzly, and ellijDtical in section, as in the negroes. The colour of the skin is very dark, although not abso- lutely black. The head is of roundish (brachycephalic) form, the cephalic index of the skull being about 82. The other cranial characters are fully described in the paj)ers just referred to. The teeth are large, but the jaws are only slightly prognathous. The features possess little of the negro type ; at all events, little of the most marked and coarser peculiarities of that type. The projecting jaws, the prominent thick lips, the broad and flattened nose of the genuine negro are so softened down in the Andamancso as scarcely to bo recognised, and yet in the relative proportions of the limb-bones, especially in the shortness of the humerus compared with the fore- arm, and in the form of the pelvis, negro afiinities are most strongly indicated. In speaking of the culture of the Andamancse, of course I only refer to their condition before the introduction of European civilisa- tion into the islands. They live ia small villages or encampments, in dwellings of simple and rude construction, built only of branches and leaves of trees. They are entirely ignorant of agriculture, and keep no poultry or domestic animals. They make rude pots of clay, sun-dried, or partially baked in the fire, but these are hand-made, as they are ignorant of the use of the potter's wheel. Their clothing is of the scantiest descrii)tion, and what little they have serves chiefly for decorative or ornamental puri)oses, and not for keeping the body warm. They make no use of the skins of animals. They have fairly well-made dug-out canoes and outriggers, but fit only for navigating the numerous creeks and straits between the islands, and not for voyages in the open sea. They are expert swimmers and divers. Though constantly using fire, they are quite ignorant of the art of producing it, and have to expend much care and labour in keeping up a constant su2)i)ly of burning or smouldering wood. They are ignorant of all metals ; but for domestic purposes make great use of shells, especially a species of Cijrene found abundantly on the shores of the islands, also quartz chips and flakes, and bamboo knives. They have stone anvils and hammers, and they make good string from vegetable fibres, as well as baskets, fishing nets, sleeping mats, &c. Their princij^al weapons are the bow and arrow, in the use of which they are very skilful. They have harpoons for killing turtle and fish, but no kind of shield or breastplate for defence when fighting. The natural * See "On the Osteology and AflSnitiea of the Natives of the Andaman Islands" ('Journal Anthropologic il Institute,' vol. ix. p. 108, 1879); and "Addi- tional Observations on the Osteology of the Natives of the Andaman Islands " (ibid. vol. xiv. p. 115, 1884). 1888.] on the Pygmy Baces of Men. 273 fertility of the island supplies them with abundance and variety of food all the year round, the purveying of which afifurds occupation and amusement for the greater part of the male population. This consists of pigs (^Sus andamanensis), which are numerous on the islands, paradoxureSjdugong. and occasionally porpoise, iguanas, turtles, turtles' eggs, many kinds of fish, prawns, mollusks, larvae of large wood-boring and burrowing beetles, honey, and numerous roots (as yams), fruits, and seeds. The food is invariably cooked before eating, and generally taken when extremely hut. They were ignorant of all stimulants or intoxicating di'inks — in fact, water was their only beverage ; and tobacco, or any substitute for it, was quite unknown till introduced by Europeans. As with all ether human beings existing at present in the world, however low in the scale of civilisation, the social life of the Andama- nese is enveloped in a complex maze of unwritten law or custom, the intricacies of which are most difficult for any stranger to unravel. The relations they may or may not marry, the food they are obliged or forbidden to partake of at particular epochs of life or seasons of the year, the words and names they may or may not jDronounce ; all these, as well as their traditions, sujjerstitions, and beliefs, their occupations, games, and amusements, of which they seem to have had no lack, would take far too long to describe here ; but before leaving these interesting people, I may quote an observation of Mr. Man's, which, imless he has seen them with too coideur-de-rose eyesight, throws a very favourable light upon the primitive unsophisticated life of these poor little savages, now so ruthlessly broken into and destroyed by the exio-encies of oui' ever-extending empire. " It has been asserted," Mr. Man says, " that the ' communal marriage ' system prevails among them, and that ' marriage is nothing more than taking a female slave ' ; but, so far from the contract being regarded as a merely temporary arrangement, to be set aside at the will of either party, no incompatibility of temper or other cause is allowed to dissolve the union ; and while bigamy, polygamy, polyandry, and divorce are unknown, conjugal fidelity till death is not the exception but the rule, and matrimonial difierences, which, however, occur but rarely, are easily settled with or without the in- tervention of friends." In fact, Mr. Man goes on to say, " One of the most striking features of their social relations is the mai'ked equality and aflection which subsists between husband and wife," and " the consideration and respect \\dth which women are treated micrht with advantage be emulated by certain classes in our own land." It should also be mentioned that cannibalism and infanticide, two such common incidents of savage life, were never practised by them. We must now pass to the important scientific question, Who are the natives of the Andaman Islands, and where, among the other races of the human species, shall we look for their nearest relations '? It is due mainly to the assiduous researches into all the docu- mentary evidence relating to the inhabitants of Southern Asia and 274 Professor Flower [April 13, the Indian Archipelago, conducted tLroiigh many years by M. do Quatrefages, in some cases with the assistance of his colleague M. Hamy, that the facts I am about to put before you have been prominently brought to light, and their significance demonstrated. It is well known that the greater part of the large island of New Guinea, and of the cbain of islands extending eastwards and south- wards from it, including the Solomon Islands, the New Hebrides, and New Caledonia, and also the Fijis, are still inhabited mainly by peojile of dark colour, frizzly hair, and many characteristics allying them to the negroes of Africa. These constitute the race to which the term Melanesian is commonly applied in this country, or Oceanic negroes, the " Papouas " of Quatrefages. Their area at one time was more extensive than it is now, and has been greatly encroached upon by the brown, straight-haired Polynesian race with Malay aflinitics, now inhabiting many of the more important islands of the Pacific, and the mingling of which with the more aboriginal Melanesians in various proportions has been a cause, among others, of the diverse aspect of the population on many of the islands in this extensive region. These Papouas, or Melanesians, however, differ greatly from the Andamanese in many easily defined characters, which are, especially, their larger stature, their long, narrow, and high skulls, and their coarser and more negro-like features. Although undoubt- edly allied, w^c cannot look to them as the nearest relations of our little Andamanese. When the Spaniards commenced the colonisation of the PJiilip- pines, they met with, in the mountainous region in the interior of the Island of Luzon, besides the prevailing native population, consisting of Tagals of Malay origin, very small people, of black complexion, with the frizzly hair of the African negroes. So struck were they with the resemblance, that they called them "Negritos del Monte" (little Negroes of the mountain). Their local name was Aigtas, or Inagtas, said to signify " black," and from which the word Aeta, generally now ai^j^licd to them, is derived. These people have lately been studied by two French travellers, M. Marclie and Dr. Moutano ; the result of their measurements gives 4 feet 8J inches as the average height of the men, and 4 feet GJ inches the average for the women. In many of their moral characteristics they resemble the Andamanese. The Aetas are faithful to their marriage vows, and have but one wife. The affection of parents for children is very strong, and tlie latter have for their father and mother much love and respect. The marriage ceremony, according to M. Montano, is very remarkable. The aflianced pair climb two flexible trees j^l^ccd near to each other. One of the elders of the tribe bends them towards each other. When their heads touch, the marriage is legally ac- complished. A great fete, with much dancing, concludes the ceremony. It was afterwards found that the same race existed in other parts of the archipelago, Panay, Mindanao, &c., and that they entirely 1888.] on the Pijgnuj Races of Men. 275 peopled some little islands — among otlicis, Bongas Island, or " Isla de los Negros." As the islands of these eastern seas have become better known, further discoveries of the existence of a small Negroid population have been made in Formosa, in the interior of Borneo, Sandalwood Island (Sumba), Xulla, Bourou, Ceram, Flores, Solor, Lomblem, Pantar, Ombay, the eastern peninsula of Celebes, &c. In fact, Sumatra and Java are the only large islands of this great area which contain no traces of them except some doubtful cr< ss-breeds, and some remains of an industry which appears not to have passed beyond the Age of Stone. The Sunda Islands form the sonthern limit of the Negrito area ; Formosa, the last to the north, where the race has preserved all its characters. But beyond this, as in Loo Choo, and even in the south- cast portion of Japan, it reveals its former existence by the traces it has left in the present population. That it has contributed considerably to form the population of New Guinea is unquestionable. In many parts of that great island, small round-headed tribes live more or less distinct from the larger and longer-headed people who make up the bulk of the population. But it is not only in the islands tbat the Negrito race dwell. Traces of them are found also on the mainland of Asia, but everywhere under the same conditions : in scattered tribes, occupying the more inaccessible mountainous regions of countries otherwise mainly inhabited by other races, and generally in a condition more or less of degradation and barbarism, resulting from the oppression with which they have been treated by their invading conquerers ; often moreover, so much mixed that their original characters are scarcely recognisable. The Semangs of the interior of Malacca in the Malay peninsula, the Sakays from Perak, the Moys of Annam, all show traces of Negrito blood. In India proper, especially among the lowest and least civilised tribes, not only of the central and southern districts, but almost to the foot of the Himalayas, in the Punjab, and even to the west side of the Indus, according to Quatrefages, frizzly hair, negro features, and small stature, are so common that a strong argument can be based on them for the belief in a Negrito race forming the basis of the whole pre- Aryan, or Dravidian as it is generally called, population of the peninsula. The crossing that has taken place with other races has doubtless greatly altered the physical characters of this people, and the evidences of this alteration manifest themselves in many ways ; sometimes the curliness of the hair is lost by the admixture with straight-haired races, while the black complexion and small stature remain ; sometimes the stature is increased, but the coloiu\ which seems to be one of the most persistent of characteristics, remains. The localities in which the Negrito people are found in their greatest purity, either in almost inaccessible islands, as on the Audamans, or elsewhere in the mountainous ranges of the interior only ; and their social condition and traditions, wherever they exist — all point to the fact that they were the earliest inhabitants ; and that the Monoolian 276 Professor Flower [April 13, and Malay races on the east, and the Aryans on the west, which are now so rapidly exterminating andrejjlacing them, are later comers into the land, exactly as, in the greater j^art of the Pacific Ocean, territory formerly occupied by the aboriginal dark, frizzly-haired Negroid Melanesians has been gradually and slowly invaded by the brown Polynesians, who in their turn, but by a much more rapid process, are being replaced by Europeans. We now see what constitutes the great interest of the Andamanese natives to the student of the ethnological history of the Eastern world. Their long isolation has made them a remarkably homogeneous race, stamping them all with a common resemblance not seen in the mixed races generally met with in continental areas. For although, as with most savages, marriages within the family (using the term in a very wide sense) are most strictly forbidden, all such alliances have necessarily been confined to natives of the islands. They are the least modified representatives of the people who were, so far as we know, the primitive inhabitants of a large portion of the earth's surface, but who are now verging on extinction. It is, however, not necessary to suppose that the Andaman Islanders give us the exact characters and features of all the other branches of the race. Difierences in detail doubtless existed — differences which are almost always sure to arise whenever races become isolated from each other for long periods of time. In many cases the characters of the ancient inhabitants of a land have been revealed to us by the preservation of their actual remains. Unfortunately we have as yet no such evidence to tell us of the former condition of man in Southern Asia. We may, however, look U2)on the Andamanese, the Actus, and the Scmangs, as living fossils ; and by their aid conjecture the condition of the whole population of the laud in ancient times. It is possible, also, to follow Quatrefages, and to sec in them the origin of the stories of the Oriental pygmies related by Ctesias and by Pliny. We now pass to the continent of Africa, in the interior of which the pygmies of Homer, Herodotus, and Aristotle have generally been X)laced. Africa, as is well known, is the home of another great branch of the black, frizzly-haired, or Ethiopian division of the human si)ecies, which does, or did till lately, occupy the southern two-thirds of this great continent, the northern third being inhabited by Hamite and Semite branches of the great white or Caucasian primary division of the human species, or by races resulting from the mixture of these with the Negroes. But besides the true Negro, there has long been known to exist in the southern part of the continent a curiously modi- fied type, consisting of the Hottentots, and the Bushmen — Bosjesmen (men of the woods) of the Dutch colonists — the latter of whom, on account of their small size, come within the scope of the present sub- ject. They lead the lives of the most degraded of savages, dwelling among the rocky and more inaccessible mountains of the interior, making habitations of the natural caves, subsisting entirely by the 1888.J on ilie Pygmy Races of 3Ien. 277 chase, being most export in the use of the bow and arrow, and treated as enemies and outcasts by the surrounding and more civilised tribes, whose flocks and herds they show. little respect for when other game is not within reach. The physical characters of these people are well known, as many specimens have been brought to Euroi^e alive for the puvjDose of exhibition. The hair shows the extreme of the frizzly type ; being shorter and less abundant than that of the ordinary Negro, it has the appearance of growing in separate tufts, which coil up together into rouud balls compared to " peppercorns." The yellow complexion differs from that of the Negro, and, combined with the wide cheek-bones and form of the eyes, so much recalls that of certain of the pure yellow races that some anthropologists are inclined to trace true Mongolian affinities and admixture, although the extreme crispness of the hair makes such a supposition almost impossible. The width of the cheek-bones and the narrowness of the forehead and the chin give a lozenge-shape to the front view of the face. The forehead is prominent and straight ; the nose extremely flat and broad, more so than in any other race, and the lips j)rominent and thick, although the jaws are less prognathous than in the true Negro races. The cranium has many special characters by which it can be easily distinguished from that of any other. It has generally a very feminine, almost infantile, appearance, though the capacity of the cranial cavity is not the smallest, exceeding that of the Andamanese. In general form the cranium is rather^ oblong than oval, having straight sides, a flat top, and especially a vertical forehead, which rises straight from the root of the nose. It is moderately doli- chocephalic or rather mesaticephalic, the average index of ten specimens being 75" 4. The height is in all considerably less than the breadth, the average index being 71*1. The glabella and infra- orbital ridges are little developed, except in the oldest males. The malar bones project much forwards, and the space between the orbits is very wide and flat. The nasal bones are extremely small and depressed, and the aperture wide ; the average nasal index being 60 * 8, so they are the most platyrhine of races. A\ ith regard to the stature, we have not yet sufficient materials for giving a reliable average. Quatrefages, following Barrow, gives 4 feet 6 inches for the men, and 4 feet for the women, and speaks of one individual of the latter sex, who was the mother of several children, measuring only 3 feet 9 inches in height , but later observa- tions (still, however, insufficient in number) give a rather larger stature: thus Topinard places the average at 1-404 metre, or 4 feet 74 inches ; and Fritsch, who measured six male Bushmen in South Africa, found their mean height to be 1 * 444 metre, or nearly 4 feet 9 inches. It is probable that, taking them all together, they differ but little in size from the Andamanese, although in colour, in form of head, in features, and in the jH'oportions of the body, they are ividely removed from them. There is every reason to believe that these Bushmen represent the 278 Professor Flower [April 18, earliest race of which we have, or arc ever likely to liave, any know- ledge, which inhabited the southern portion of the African continent, but that long before the advent of Europeans n2)on the scene, they had been invaded from the north by Negro tribes, who, being superior in size, strength, and civilisation, had taken possession of the greater part of their territories, and mingling freely with the aborigines, had produced the mixed race called Hottentots, who retained the culture and settled pastoral habits of the Negroes, with many of the physical features of the Bushmen. These, in their turn, encroached upon by the jDure-bred Bantu Negroes from the north, and by the Dutch and English from the south, are now greatly diminished, and indeed threatened with the same fate that will surely soon befall the scanty remnant of the early inhabitants who still retain their primitive type. At present the habitat of the Bushman race is confined to certain districts in the south-west of Africa, from the confines of the Cape Colony as far north as the shores of Lake Ngami. Further to the north the great equatorial region of Africa is occupied by various Negro tribes, using the term in its broadest sense, but belonging to the divisions which, on account of peculiarities of language, have been grouped together as Bantu. They all present the common physical characteristics typical of the Negro race, only two of which need be sj)ecially mentioned here — medium or large stature, and dolicho- cephalic skull (average cranial index about 73*5). It is at various scattered places in the midst of these, that the only other small people of which I shall have to speak, the veritable pygmies of Homer, Herodotus, and Aristotle, according to Quatre- fages, are still to be met with.* The first notice of the occurrence of these in modern times is con- tained in " The strange adventures of Andrew Battell of Leigh in Essex, sent by the Portugals prisoner to Angola, who lived there, and in the adjoining regions near eighteen years" (1589 to 1G07), pub- lished in ' Purchas his Pilgrimes ' (1625), lib. vii. chaj). iii. p. 983 : — " To the north-east of 3Icmi-Kesoch, are a kind of little people, called Matlmhas ; which are no bigger than Boyes of twelve yeares old, but very thicke, and live only upon flesh, which they kill in the woods with their bows and darts. They pay tribute to Mani-Kesoch, and bring all their Elephants' teeth and tayles to him. They will not enter into any of the MaramhcCs houses, nor will suffer any to come where they dwell. And if by chance any Mararaha or people of Longo pass where they dwell, they will forsake that place and go to another. The women carry Bows and Arrows as well as the men. And one of these will walk in the woods alone and kill the Pongos with their poysoned Arrows." * The scattered information upon this subject was first collected together by Hamy iu his "Essai de co-ordination des Mate'riaux re'ceranient reeueillis sur Fetiinologio des Ne'grilles ou Pygmees do I'Afrique c'quatoriale," 'Bull. Soc. d' Anthropologic de Paris,' tome ii. (ser. iii.), 1879, p. 79. 1888.] on the Pygmy Baces of Men. 279 Battell's narrative, it should be said, is generally admitted as having an air of veracity about it not always conspicuous in the stories of travellers of his time. In addition to the observations on the human inhabitants, it contains excellent descriptions of animals, as the pongo or gorilla, and the zebra, now well known, but in his day new to Europeans. Dapper, in a work called 'Description de la Basso Ethiopie,' published in Amsterdam in 1686, speaks of a race of dwarfs inhabiting the same region, which he calls Minios or Bakhe-Bakke, but nothing further was heard of these people until quite recent times. A German scientific expedition to Loango, the results of w'hich were published in the ' Zoitschrift fiir Ethnologic,' 1874, and in Hartmann's work, 'Die Negritier," obtained, at Chinchoxo, photographs and descriptions of a dwarf tribe called " Baboukos," whose heads were proportionally large and of roundish form (cephalix index of skull, 78 to 81). One individual, supposed to be about forty years of age, measured 1-365 metres, rather under 4 feet 6 inches. Dr. Touchard, in a " Notice sur le Gabon," published in the ' Eevue Maritime et Coloniale' for 1861, describes the recent destruc- tion of a population established in the interior of this country, and to which he gives the name of " Akoa." They seem to have been exter- minated by the M'Pongos in their expansion towards the west. Some of them, however, remained as slaves at the time of the visit of Admiral Fleuriot de Langle, who in 1868 photographed one (measuring about 4 feet 6 inches high) and brought home some skulls, which were ex- amined by Hamy, and all proved very small and sub-brachycephalic. Another tribe, the M'Boulous, inhabiting the coast north of the Gaboon river, have been described by M. Marche as probably the primitive race of the country. They live in little villages, keeping entirely to themselves, though surrounded by tho larger negro tribes, M'Pongos and Bakalais, who are encroaching upon them so closely that their numbers are rapidly diminishing. In 1860 they were not more than 3000 ; in 1879 they were much less numerous. They are of an earthy-brown colour, and rarely exceed 1 • 600 metre in height (5 feet 3 inches). In the rich collections of skulls made by Mr. R. B. Walker and by M. Du Chaillu, from the coast of this region, are many which are remarkable for their small size and round form. Of many other notices of tribes of negroes of diminutive size, living near the west coast of Equatorial Africa, I need only mention that of Du Chaillu, who gives an interesting account of his visit to an Obongo village in Ashango-land, between the Gaboon and the Congo ; although unfortunately, owing to the extreme shyness and suspicion of the inhabitants, he was allowed little opportunity for anthropological observations. He succeeded, however, in measuring one man and six women ; the height of the former was 4 feet 6 inches, the average of the latter 4 feet 8 inches.* A Journey to Ashango-land,' 18G7, p. 315. 280 Professor Flower [April 13, Far further into tlio interior, towards the centre of tlic region contained in the great bend of the Congo or Livingstone River, Stanley heard of a numerous and independent population of dwarfs, called " Watwas," who, like the Batimbas of Battel!, are great hunters of elephants, and use poisoned arro.vs. One of tliese he met with at Ikondu, was 4 feet 6J inches high, and of a chocolate brown C(dour.* More recently Dr. Wolif describes under the name of " Batouas " (perhaps the same as Stanley's Watwas), a people of lighter colour than other negroes, and never exceeding 1 • 40 metres (4 feet 7 inches) high, but whose average is not more than 1-30 (4 feet 3 inches), who occupy isolated villages scattered through the territory of the Bahoubas, with whom they never mix."]" Penetrating into the heart of Africa from the north-east, in 1870, Dr. Schweinfurth first made us acquainted with a diminutive race of people who have since attained a considerable anthroj)ological notoriety. They seem to go by two names in their own country, AMa and TiJihi-tikki, the latter reminding us curiously of Dapper's Bakke-bakke, and the former, more singularly still, having been read by the learned Egyptologist, Mariette, by the side of the figure of a dwarf in one of the monuments of the early Egyptian empire. It was at the court of Mounza, king of the Monbuttu, that Schwein- furth first met with the Akkas. They apj)ear to live under the pro- tection of that monarch, who had a regiment of them attached to his service, but their real country was further to the south and west, about 3° N. lat. and 25^ E. long. From the accounts the traveller received, they occupy a considerable territory, and are divided into nine distinct tribes, each having its own king or chief. Like all the other pygmy African tribes, they live chiefly by the chase, being great hunters of the elej)hant, which they attack with bows and arrows. In exchange for one of his dogs, Schweinfurth obtained from Mounza one of these little men, whom he intended to bring to Euroj)e, but who died on the homeward journey at Berber. Un- fortunately all the measurements and observations which were made in the Monbuttu country by Schweinfurth perished in the fire which destroyed so much of the valuable material he had collected. His descriptions of their physical characters are therefore chiefly recollec- tions. Other travellers — Long, ]\Iarno, and Vossion — though not penetrating as far as the Akka country, have given observations upon individuals of the race they have met with in their travels. The Italian Miani, following the footsteps of Schweinfurth into the Monbuttu country, also obtained by barter two Akka boys, with the view of bringing them to Europe. He himself fell a victim to the fatigues of the journey and climate, but left his collections, including the young Akkas, to the Italian Geographical Society. Probably no * ' Througli the Dark Continent,' vol. ii. t ' La Gazette Geogi-aphique,' 1887, p. 153, quoted by Quatrefages. 1888.] on the Pygmy Baces of Men. 281 two individuals of a savage race have been so much honoured by the attentions of the scientific world. First at Cairo, and afterwards in Italy, Tebo (or Thibaut) and Chairallah, as they were named, were described, measured, and photographed, and have been the subjects of a library of memoirs, their bibliographers including the names of Owen, Panceri, Cornalia, Mantegazza, Giglioli and Zannetti, Broca, Hamy, and de Quatrefages. On their arrival in Italy, they were presented to the king and queen, introduced into the most fashionable society, and finally settled down as members of the household of Count Miniscalchi Erizzo, at Verona, where they received a European education, and performed the duties of pages. In reply to an inquiry addressed to my friend Dr. Giglioli, of Florence, I hear that Thibaut died of consumption on January 28th, 1883, being then about twenty-two years of age, and was buried in the cemetery at Verona. Unfortunately no scientific examination of the body was allowed, but whether Chairallah still lives or not I have not been able to learn. As Giglioli has not heard of his death, he presumes that he is still living in Count Miniscalchi's palace. One other specimen of this race has been the subject of careful observation by European anthropologists — a girl named Saida, brought home by Romolo Gessi (Gordon's lieutenant), and who is still, or was lately, living at Trieste as servant to M. de Gessi. The various scattered observations hitherto made are obviously insufficient to deduce a mean height for the race, but the nearest estimate that Quatrefages could obtain is about 4 feet 7 inches for the men, and 4 feet 3 inches for the women, decidedly inferior, therefore, to the Andamanese. With regard to their other characters, their hair is of the most frizzly kind, their complexion lighter than that of most Negroes, but the prognathism, width of nose, and eversion of lips characteristic of the Ethiopian branch of the human family are carried to an extreme degree, especially if Schweinfurth's sketches can bo trusted. The only essential point of difference from the ordinary Negro, except the size, is the tendency to shortening and breadth of the skull, although it by no means assumes the " almost spherical " shape attributed to it by Schweinfurth. Some further information about the Akkas will be found in the work, just published, of the intrepid and accomplished traveller, in whose welfare we are now so much interested, Dr. Emin Pasha, Gordon's last surviving officer in the Soudan, who, in the course of his explorations, spent some little time lately in the country of the Monbuttu. Here he not only met with living Akkas, one of whom he apparently still retains as a domestic in his service, and of whose dimensions he has sent me a most detailed account, but he also, by watching the spots where two of them had been interred, succeeded in obtaining their skeletons, which, with numerous other objects of great scientific interest, safely arrived at the British Museum in September of last year. I need hardly say that actual bones, clean, imperishable, easy to be measured and compared, not once only, but Vol. XII. (No. 82.) u 282 Professor Flower [April 13, any number of times, furnish the most acceptable evidence that an anthropologist can possess of many of the most important physical characters of a race. There we have facts which can always be appealed to in support of statements and inferences based on them. Height, proportions of limbs, form of head, characters of the face even, are all more rigorously determined from the bones than they can be on the living person. Therefore, the value of these remains, imperfect as they unfortunately are, and of course insufficient in number for the purpose of establishing average characters, is very great indeed. As I have entered fully into the question of their peculiarities elsewhere,* I can only give now a few of the most important and most generally to be understood results of their examination. The first point of interest is their size. The two skeletons are both those of full-grown people, one a man, the other a woman. There is no reason to suppose that they were specially selected as excej^tionally small ; they were clearly the only ones w^hich I^min had an oppor- tunity of procuring ; yet they fully bear out, more than bear out, all that has been said of the diminutive size of the race. Comparing the dimensions of the bones, one by one, with those of the numerous Andamanese that have passed through my hands, I find both of these Akkas smaller, not than the average, but smaller than the smallest ; smaller also than any Bushman whose skeleton I am acquainted with, or whose dimensions have been published with scientific accm-acy. In fact, they are both, for they are nearly of a size, the smallest normal human skeletons which I have seen, or of which I can find any record. I say normal, because they are thoroughly well-grown and proportioned, without a trace of the deformity almost always associated with individual dwarfishness in a taller race. One only, that of the female, is sufficiently perfect for articulation. After due allowance for some missing vertebrae, and for the intervertebral spaces, the skeleton measures from the crown of the head to the ground exactly 4 feet, or 1 '218 metre. About half an inch more for the thickness of the skin of the head and soles of the feet would complete the height when alive. The other (male) skeleton was (judging by the length of the femur) about a quarter of an inch shorter. The full-grown woman of whom Emin gives detailed dimensions is stated to be only 1-164: metre, or barely 3 feet 10 inches.f These heights are all unquestionably less than anything that has been yet obtained based upon such indisputable data. One very interesting * In a paper read before the Anthropological Institute of Great Britain and Ireland, February 14th, 1888, which will be published in the August number of the Journal. t In his letters Emin speaks of an Akka man as " 3 feet 6 inches " high though this does not profess to be a scientific accurate observation, as does the above. He says of this man that his whole body was covered by thick, stiff hair, almost like felt, as was the case with all the Akkas he had yet examined. 1888.] on the Pygmy Baces of Men. 283 and almost unexpected result of a careful examination of these skeletons is that they conform in the relative proportions of the head, trunk, and limb, not to dwarfs, but to full-sized people of other races, and they are therefore strikingly unlike the stumpy, long-bodied, short-limbed, large-headed pygmies so graphically represented fighting with their lances against the cranes on ancient Greek vases. The other characters of these skeletons are Negroid to an intense degree, and quite accord with what has been stated of their external appearance. The form of the skull, too, has that sub-brachycephaly which has been shown by Hamy to characterise all the small Negro populations of Central Africa. It is quite unlike that of the Andamanese, quite unlike that of the Bushmen. They are obviously Negroes of a special type, to which Hamy has given the appropriate term of Negrillo. They seem to have much the same relation to the larger long-headed African Negroes that the small round-headed Negritos of the Indian Ocean have to their larger long-headed Melanesian neighbours. At all events, the fact now seems clearly demonstrated that at various sj)ots across the great African continent, within a few degrees north and south of the equator, extending from the Atlantic coast to near the shores of the Albert Nyanza (30^ E. long.), and perhaps, from some indications which time will not allow me to enter into now (but which will be found in the writings of Hamy and Quatrefages), even further to the east, south of the Galla land, are still surviving, in scattered districts, communities of these small Negroes, all much resembling each other in size, appearance, and habits, and dwelling mostly apart from their larger neighbours, by whom they are every- where surrounded. Our information about them is still very scanty, and to obtain more would be a worthy object of ambition for the anthroj)ological traveller. In many parts, especially at the west, they are obviously holding their own with difficulty, if not actually dis- appearing, and there is much about their condition of civilisation, and the situations in which they are found, to induce us to look upon them, as in the case of the Bushmen in the south and the Negritos in the east, as the remains of a population which occupied the land before the incoming of the present dominant races. If the account of the Nasa- monians related by Herodotus be accepted as historical, the river they came to, " flowing from west to east," must have been the Niger, and the northward range of the dwarfish people far more extensive twenty- three centuries ago than it is at the present time. This view opens a still larger question, and takes us back to the neighbourhood of the south of India as the centre from which the whole of the great Negro race spread, east over the African continent, and west over the islands of the Pacific, and to our little Andamanese fellow subjects as probably the least modified descendants of the primitive members of the great branch of the human species characterised by their black skins and frizzly hair. [W. H. F.] u 2 284 Sir William B. Grove [April 20, WEEKLY EVENING MEETING, Friday, April 20, 1888. Edwabd Woods, Esq. M. Inst. C.E. Vice-President, in the Chair. The Eight. Hon. Sir William R. Grove, M.A. D.CL. LL.D. F.E.S. M.B.L Antagonism. Some months ago, shortly after I had resigned my office of Judge of the High Court, I was expressing to a friend my fear of the effect of having no compulsory occupation, when he said, by way of con- solation, " Never mind, ' for Satan finds some mischief still for idle hands to do.' " You may possibly in the course of this evening think he was right. I have chosen a title for my lecture which may not fully convey to your minds the scope of the views which I am going to submit to you. I propose to adduce some arguments to show that " antagonism," a word generally used to signify something disagreeable, pervades all things ; that it is not the baneful thing which many consider it ; that it produces at least quite as much good as evil ; but that, whatever be its effect, my theory — call it, if you will, speculatioa — is that it is a necessity of existence, and of the organism of the universe so far as we understand it ; that motion and life cannot go on without it ; that it is not a mere casual adjunct of Nature, but that without it there would be no Nature, at all events as we conceive it; that it is inevitably associated with unorganised matter, with organised matter, and with sentient beings. I am not aware that this view, in the breadth in which I suggest it, has been advanced before. Probably no idea is new in all respects in the present period of the world's history. It has been said by a desponding pessimist that " There is nothing new, and nothing true, and nothing signifies," but I do not entirely agree with him; I believe that in what I am about to submit there is something new and true in the point of view from which I regard the matter ; whether it signifies or not is for you to judge. The universality of antagonism has not received the attention it seems to me to deserve from the fact of the element of force, or rather of the conquering force, being mainly attended to, and too little note taken of the element of resistance unless the latter vanquishes the force, and then it becomes, popularly speaking, the force, and the former force the resistance. 1888.] on Antagonism. 285 There are propositions applying more or less to what I am going to say of some antiquity. Heraclitus, quoted by Prof. Huxley, said : " War is the father and king of all things." Hobbes said war is the natural state of man, but his expressions have about them some little ambiguity. In Chapter I. of the ' De Corpore Politico ' he says, " Irresistible might in a state of nature is right," and " The estate of man in this natural liberty is war." Subsequently he says : " A man gives up his natural right, for when divers men having right not only to all things else, but to one another's persons, if they use the same there ariseth thereby invasion on the one part and resistance on the other, which is war, and therefore contrary to the laiv of Nature, the sum whereof consistetk in making peace." I can only explain this apparent inconsistency by supposing he meant *' law of Nature " to be something different from *' the natural estate of man," and that the making peace was the first effort at contract, or the beginning of law ; but then why call it the ^'laio of Nature,'' where he says might is right? There is some obscurity in the passage. The Persian divinities, Ormuzd and Ahriman, were the supposed rulers or representatives of good and evil, always at war, and causing the continuous struggles between human beings animated respectively by these two principles. Undoubtedly good and evil are antagonistic, but antagonism, as I view it, is as necessary to good as to evil, as necessary to Ormuzd as to Ahriman. ' Zoroaster's religion of a Divine being, one and indivisible, but with two sides, is, to my mind, a more philosophical conception. The views of Lamarck on the modification of organic beings by effort, and the establishment of the doctrine of Darwin as to the effects produced by the struggle for existence and domination, come much nearer to my subject. Darwin has shown how these struggles have modified the forms and habits of organised beings, and tended to increased differentiation, and Prof. Huxley and Herbert Spencer have powerfully promoted and expanded these doctrines. To the latter we owe the happy phrase, " survival of the fittest," and Prof. Huxley has recently, in a paper in the 'Nine- teenth Century,' anticipated some points I should have adverted to as to the social struggles for existence. To be anticipated, and by a very short period, is always trying, but it is more trying when what you intended to say has been said by your predecessor in more terse and appropriate language than you have at your command. I propose to deal with "antagonism" inductively, i.e. with facts derived from observation alone, and not to meddle with spiritual matters or with consequences. Let us begin with what we know of the visible universe, viz. suns, planets, comets, meteorites, and their effects. These are all pulling at each other, and resisting that pull by the action of other forces. Any change in this pulling force produces a change, or, as it is called, perturbation, in the motion of the body pulled. The planet 286 Sir William B. Grove [April 20, Neptune, as you know, was discovered by the effect of its pulling force on another planet, the latter being deflected from its normal course. When this pulling force is not counterbalanced by other forces, or when the objects pulled have not sufficient resisting power, they fall into each other. Thus, this earth is daily causing a bom- bardment of itself by drawing smaller bodies — meteorites — to it, 20,000,000 of which, visible to the naked eye, fall on an average into our atmosphere in each twenty-four hours, and of those visible through the telescope, 400,000,000 are computed to fall within the same period. Mr. Lockyer has recently given reasons for supposing the luminosity of nebulae, or of many of them, is due to collisions or friction among the meteorites which go to form them ; but his paper on the subject is not yet published. You must get from Mr. Lockyer the details of his views. I hope he may, at one of these evening meetings, give you a resume of them from the place I now occupy. What is commonly called centrifugal force does not come from nothing ; it depends upon the law that a body falling by the influence of attraction, not upon, but near to, the attracting body, whirls round the latter, describing one of the curves knowTi as conic sections. Hence a meteorite may become a planet or satellite (one was supposed to have become so to this earth, but I believe the observations have not been verified) ; or it may go off in a j^arabola as comets do ; or again, this centrifugal force may be generated by the gradual accre- tion of nebulous matter into solid masses falling near to, or being thrown off from the central nucleus, the two forces (centrifugal and centripetal) being antagonistic to each other, and the relative move- ments being continuous, but probably not perpetual. Our solar system is also kept in its place by the antagonism of the surrounding bodies of the Kosmos i3ulling at us. Suppose half of the stars we see, i. e. all on one side of a meridian line, were removed, what would become of our solar system ? It would drift away to the side where attraction still existed, and there would be a wreck of matter and a crash of worlds. It is very little known that Shakespeare was acquainted with this pulling force. He says, by the mouth of Cressida — " But the strong base and building of my love Is as the very centre of the earth, Drawing all things to it " — a very accurate description of the law of gravitation, so far as this earth is concerned, and written nearly a century before Newton's time. But in all probability the collisions of meteorites with the earth and other suns and planets are not the only collisions in space. I know of no better theory to account for the phenomena of temporary stars, such as that which appeared in 1866, than that they result from the collision of non-luminous stars, or stars previously invisible to us. That star burst suddenly into light, and then the luminosity gradually faded, the star became more and more dim, and ultimately disappeared. The spectrum of it showed that the light was compound, and had pro- 1888.] on Antagonism. 287 bably emanated from two different sources. It was probably of a very high temperature. If this theory of temporary stars be admitted, we get a nebula of vapour or star dust again, and so may get fresh instances of the nebular hypothesis. Let us now take the earth itself. It varies in temperature, and consequently the particles at or near its surface are in continuous movement, rubbing against each other, being oxidized or deoxidized, either immediately or through the medium of vegetation. This also is continuously tearing up its surface and changing its character. Evaporation and condensation, producing rain, hail, and storms, notably change it. Force and resistance are constantly at i^lay. The sea erodes rocks and rubs them into sand. The sea quits them, and leaves traces of its former presence by the fossil marine shells found now at high altitudes. Eocks crumble down and break other rocks or are broken by them ; avalanches are not uncommon. The interior of the earth seems to be in a perpetual state of commotion, though only recurrent to our observation. Earthquakes in various places from time to time, and doubtless many beneath the sea of which we are not cognizant, nor of other gradual upheavals and depressions. Through- out it nothing that we know of is at rest, and nothing can move without changing the position of something else, and this is antagonism. Metals rust at its surface, and probably they or their oxides, chlorides, &c., are in a continuous state of change in the interior. Nothing that we know of is stationary. The earth as a whole seems so at first sight, but its surface is moving at the rate of some seventeen miles a minute at the equator ; and standing at either of the poles — an experi- ment which no one has yet had an opportunity of trying — a man would be turned round his own axis once in every twenty-four hours, while the earth's motion round the sun carries us through sj)ace more than a million and a half of miles a day. The above changes produce motion in other things. The earth pulls the sun and planets, and in different degrees at different portions of its orbit. Before I pass from inorganic to organized matter I had better deal with what may perhaps strike you as the most difficult jjart of my subject, viz. light. Where, you may say, is there antagonism in the case of light ? Light exercises its force upon such minute portions of matter that until the period of the discovery of photo- graphy its physical and chemical effects were almost unknown. Such effects as bleaching, uniting some gases, and affecting the colouring matter of vegetables, were partially known but little attended to ; but photography created a new era : I shall advert to this presently. The theories of light, however, involved matter and motion. The corpuscular theory, as you well know, supposed that excessively small particles were emitted from luminous bodies, and travelled vdih enormous velocity. The undulatory theory, which supplanted it, supposed that luminous bodies caused undulations or vibrations in a highly tenuous matter called ether, which is supposed to exist 288 Sir William B. Grove [April 20, tLroTigliout the interplanetary spaces and tliroughout the universe so far as we know it. Some suppose this ether to be of a specific character differing from that of ordinary gases, others that it is in the nature of a highly attenuated gas ; but, whatever it be, it cannot be affected by undulations or vibrations without being moved, and when matter is moved by any force it must offer resistance to that force, and hence we get antagonism between force and resistance. Light also takes time in overcoming this resistance, i. e. in pushing aside the ether. It travels, no doubt, at a good pace — about 190,000 miles in a second ; but even at this rate, and without being particular as to a few millions of miles, it takes three years and a quarter to reach us from the star which, so far as we know, is the nearest to us, viz. a Centauri. The ether, or whatever it may be called, tenuous as it is, is not unimportant, though it be not heavy. Without it we should have no light and possibly no heat, and the consequences of its absence would be rather formidable. I believe you have heard Dr. Tyndall on this subject. Supposing the visible universe to be as it is now supjiosed to be, i. e. in no part a mere vacuum, there can be no force without resistance in any part of it. But photography carries us further, it shows us that light acts on matter chemically, that it is capable of decomposing or forcing asunder the constituents of chemical compounds, and is therefore a force met by resistance. In the year 185G I made some experiments, published in the ' Philosophical Magazine ' for January 1857, which seemed to me to carry still further what I may call the molecular fight between light and chemical affinity, and among them the follow- ing. Letters cut out of jDaper are placed between two polished squares of glass with tin-foil on the outsidcs. It is then* electrized like a Leyden jar, for a few seconds, the glasses separated, the letters blown off", and the inside of one of the glasses covered with i^hotograi)hic collodion. This is then exposed to diffusp daylight, and on being immersed in the nitrate of silver bath the part which had been covered with the paper comes out dark, the remainder of the plate being un- affected. (This result was shown by the electric light lantern.) Ih this case we see that another imponderable force, electricity, invisibly affects the surface of glass in such a way that it conveys to another substance of definite thickness, viz. the prepared collodion, a change in the chemical relations of the substance (iodide of silver) pervading it, enabling it to resist that decomposition by light which but for some unseen modification of the surface of the glass plate it would have undergone, and no doubt the force of light being unable to effect its object was reflected or dispersed, and instead of changing its mode of motion in effecting chemical decomposition, it goes off on other business. The visible effect is in the collodion film alone. I have stripped that off, and the imprint remains on it, the surface of the glass being, so far as I could ascertain, unaffected. Thus in the film over the protected part, light conquers chemical affinity ; in that over the non-protected part, chemical af&nity resists and conquers light, 1888.] on Antagonism. 289 which has to make an ignominious retreat. It is a curious chapter in the history of the struggles of molecular forces, and probably similar contests between light and chemical or physical attractions go on in many natural phenomena, some forms of blight and some healthy vegetable changes being probably dependent on the varying effects of light, and conditions, electrical or otherwise, of the atmosphere. Let us now pass on to organic life. A blade of grass, as Burke, I believe, said as a figure of sj^eech, is fighting with its neighbours. It is robbing them, and they are trying to rob it — no agreement or contract, simply force opposed to force. This struggle is good for the grass ; if it got too much nutriment it would become diseased. The struggle keeps it in health. The rising of sap in trees, the assimilation of carbon, the process of growth, the strengthening themselves to resist prevalent winds, and many other instances might be given, which afford examples of the internal and external struggles in vegetable life. I will now proceed to consider animal life, and in this case I will begin with the internal life of animals, which is a continual struggle. That great pumj) the heart is continuously beating — that is, conquer- ing resistance. It is forcing the blood through the arteries, they assisting in squeezing it onwards. If they give way, the animal dies ; if they become rigid and resist too much, the animal dies. There must be a regulated antagonism, a rhythmical pulsation, the very term involving force and resistance. That 'the act of breathing is antago- nistic scarcely needs argument. The muscular action by which the ribs are made to ojien out and close alternately, in order to inhale and exhale air, and other physiological changes which I cannot here go into, necessitate a continuous fight for life. So with digestion, assi- milation, and other functions, mechanical and chemical forces and resistances come into play. Since this lecture was written, I have heard of a discovery made, I am informed, by Prof. Metschnikoff, and which has brought to light a singular instance of internal antagonism. He is said to have proved that the white corpuscles of the blood are permanent enemies of Bacteria, and by inoculation will absorb j^oisonous germs ; a re- current war, as it appears, going on between them. If the corj)uscle is the conqueror, the Bacteria are swallowed up, and the patient lives. If the corpuscles are vanquished, the patient dies, and the Bacteria Hve, at all events for a time. If the theory is founded, it affords a strong additional argument to the doctrine of internal antagonism. Possibly if there were no Bacteria, and the corpuscles had nothing to do, it would be worse for them and the animal whom they serve. Let us now consider the external life of animals. I will take as an instance, for a reason which you will soon see, the life of a wild rabbit. It is throughout its life, except when asleep (of which more presently), using exertion, cropping grass, at war with vegetables, &c. If it gets a luxurious pasture it dies of repletion. If it gets too little it dies of inanition. To keep itself healthy it must exert itself for 290 Sir William B. Grove [April 20, its food ; this, and perhaps the avoiding its enemies, gives its exercise and care, brings all its organs into use, and thus it acquires its most perfect form of life. I have witnessed this effect myself, and that is the reason why I choose the rabbit as an example. An estate in Somersetshire, which I once took temporarily, was on the slope of the Mendip Hills. The rabbits on one part of it, viz. that on the hill- side, were in perfect condition, not too fat nor too thin, sleek, active, and vigorous, and yielding to their antagonists, myself and family, excellent food. Those in the valley, where the pasturage was rich and luxui'iant, were all diseased, most of them unfit for human food, and many lying dead on the fields. They had not to struggle for life, theii" short life was miserable and their death early, they wanted the sweet uses of adversity — that is, of antagonism. The same story may be told of other animals. Carnivora, beasts or birds of prey, live on weaker animals ; weaker animals herd together to resist, or, by better chance of warning, to escape, beasts of prey; while they, the Herbivora, in their turn are destroying vegetable organisms. I now come to the most delicate part of my subject, viz. man (I in- clude women of course !). Is man exempt from this continual struggle '? It is needless to say that war is antagonism. Is not peace so also, though in a different form ? It is a common-place remark to say that the idle man is worn out by ennui, i.e. by internal antagonism. Kingsley's " Do-as-you-like " race — who were fed by a substance dro2)ping from trees, who did no work, and who gradually degenerated until they became inferior to apes, and ultimately died out from having nothing to do, nothing to struggle with — is a caricature illustrative of the matter. That the worry of competition is nearly equivalent to the hardships and perils of military life, seems proved to me by the readiness with which military life is voluntarily undertaken, ill as it is paid. If it were well paid, half our men would be in the military or naval service, and I am not sure that we should not have regiments of Amazons ! The increased risk of life or limbs and the arduous natm-e of the work do not prevent men belonging to all classes from entering these services, little remunerative as they are. Others take the risks of travelling in the deserts of Africa or wintering in the polar regions, of being eaten by lions or frozen to death, of falling from a Swiss mountain or foundering in a yacht, in preference to a life of tranquillity ; and sportsmen prefer the danger of endeavour- ing to kill an animal that can and may kill them, to shooting tame pheasants at a hattue or partridges in a turnip-field. Then, in what is euphemistically called a life of peace, buyer and seller, master and servant, landlord and tenant, debtor and creditor, are all in a state of simmering antagonism ; and the inventions and so-called improvements of applied science and art do not lessen it. Exercise is antagonism ; at each step force is used to lift wj) our bodies and push back the earth ; as the eminent Joseph Montgolfier said, that when he saw a company dancing, he mentally inverted his 1888.] on Antagonism, 291 view and imagined the earth dancing on the dancers' feet, which it most unquestionably did. Indeed, his great invention of balloons was guessed at by his witnessing a mild form of antagonism between heat and gravitation. He, being a dutiful husband, was airing his wife's dresses, who was going to a ball. He observed the hot air from the fire inflated the light materials, which rose up in a sort of spheroidal form (you may some of you have noticed this form in dress ! ). This gave him the idea of the fire-balloon, which, being a large pajjer-maker at Annonay, he forthwith experimented on, and hence we got aerial navigation. This anecdote was told me by his ne^Dhew M. Seguin, also an eminent man. Even what we call a natural death is a greater struggle than that which other animals go through, and is, in fact, the most artificial of all deaths. The lower animals, practically speaking, do experience a natural death, i. e. a violent or unforeseen death. As soon as their powers decline to such an extent that they cannot take part in the struggle for existence, they die or are killed, generally quickly, and their sufferings are not protracted by the artificial tortures arising from the endeavours to prolong life. Let us now pass from individuals to communities. Is there less antagonism now than of yore ? Do the nations of Europe now form a happy family ? Are the armaments of Continental nations, or is the navy of this country, less than in former years '? The very ex- pression " the Great Powers " involves antagonism. As with wars and revolutions, so, as I have said, with regard to individuals, during our so-called peace, the fight is continuous among communities. If the water does not boil, it simmers. Not merely are there the struggles of poor against rich going on, but the battles for position and pre-eminence are constant. The subjugated party or sect seeks first for toleration, then for equalisation, and then for domination. We call contentment a virtue, but we inculcate discontent. A father reproaches his son for not exerting himself to improve his position, and at school and college and in subsequent periods of life efforts at advancement in the social scale are recommended. Individual antagonisms, class antagonisms, political, trading, and religious antagonisms take the place of war. Can war exhibit a more vigorous and persistent antagonism than competition does ? Take the college student with ruined health ; take the bankrupt tradesman with ruined family ; take the aspirants of fashion turning night into day, and preferring gas or electric light to that of the sun : there is, to be sure, some excuse for this, as we so rarely see the latter. But our very amusements are of a combative character : chess, whist, billiards, racing, cricket, football, &c. And in all these we, in common parlance, speak of heating our opponent. Even dancino" is probably a relic and reminiscence of war, and some of its forms are of a military character. I can call to mind only one game which is not combative, and that is the game you are in some sort now playing, viz. " patience," and with, I fear, some degree of internal antagonism ! Take, again, the ordinary incidents of a day's life in London : 292 Sir William B. Grove [April 20, 15,000 to 20,000 cabs, omnibuses, vans, private carriages, &c., all struggling, the horses jmshing the earth back and themselves forwards, the pedestrians doing the same, but the horses compulsorily — they have not as yet got votes. The occupants of the cabs, vans, &c., are supposed to act from free will, but in the majority of cases they are as much driven as the horses. Insolvents trying to renew bills, rich men trying to save what they have got by saving half an hour of time. Imagine, if you can, the friction of all this, and add the bargaining in shops, the mental efforts in counting-houses, banks, &c., and road repair, now a permanent and continuous institution. Take our rail- ways : similar efforts and resistances. Drivers, signal-men, porters, &c., and the force emanating from the sun millions of years ago, and locked up in the coal-fields, as Stephenson suggested, now employed to overcome the inertia of trains and to make them push the earth in this or that direction, and themselves along its surface. Take the daily struggles in commerce, law, professions, and legislation, and sometimes even in science and literature. Politics I cannot enter upon here, but must leave you to judge whether there is not some degree of antagonism in this pursuit. In all this there is plenty of useful antagonism, plenty of useless — much to please Ormuzd and much to delight Ahriman ; but of the two extremes, over-work or stagnation, the latter would, I think, do Ahriman's work more efiiciently than the former. We cry peace when there is no peace. "Would the world, however, be better if it were otherwise ? Is the Kirvana a pleasing prospect ? Sleep, though not without its troubles and internal antagonism, is our nearest approach to it, but we should hardly wish to be always asleep. Shakespeare not only knew something about gravitation, but he also knew something about antagonism. He says, by the mouth of Agamemnon — " Sith every action that hath gone before, Whereof we have record, trial did draw, Bias and thwart, not answering the aim. And that unbodied figure of the thought That gav't surmised shape." In no case is the friction of life shown more than in the perform- ance of " duty," i. e. an act of self -resistance, a word very commonly used ; but the realisation of it is by no means so frequent. Indeed, faith in its performance so yields to scepticism that it is said that when a man talks of doing his duty, he is meditating some knavish trick. The words good and evil are correlative : they are like height and depth, parent and offspring. You cannot, as far as I can see, conceive the existence of the one without involving the conception of the other. In their common acceptation they represent the antagonism between what is agreeable or beneficial and what is painful or injurious. An old anecdote will give us the nouon of good and evil in a 1888.] 071 Antagonism. 293 slenderly educated mind. A missionary having considered that he had successfully inculcated good principles in the mind of a previously untutored savage, produced him for exhibition before a select audience, and began his catechism by asking him the nature of good and evil. " Evil," the pupil answered, " is when other man takes my wife." " Eight," said the missionary, " now give me an example of good." The answer was : " Good is when me takes other man's wife." The answer was not exactly what was expected, but was not far in dis- accord with modern views among ourselves and other so-called civilised races. I don't mean as to running away with other men's wives ! But we still view good and evil very much as affecting our own interests. At the commencement of a war each of the opposing parties view victory — i.e. the destruction of their enemies — as good, and being vanquished as evil. Congregations pray for this. States- men invoke the God of battles. Those among you who are old enough will call to mind the Crimean war. Each combatant nation gives thanks for the destruction of the enemy, each side possibly believing that they respectively are in the right, but in reality not troubling themselves much about that minor question. We (uncon- sciously perhaps) "compound for sins we are inclined to, by damning tbose we have no mind to." So in the daily life of what is called peace. The stage-coach proprietor rejoiced when he had driven his rival off the road, railway directors and shareholders now do the same, so do publicans, shopkeepers, and other jivals. We are still permeated by the old notion of good and evil. But " antagonism," as I view it, not only comprehends the relation of good and evil, but, as I have said, produces both, and is as necessary to good as to evil. Without it there woukl be neither good nor evil. Judging of the lives of our progenitors from what we see of the present races of men of less cerebral development, we may characterize them as having been more impulsive than ourselves, and as having their joys and sorrows more quickly alternated. After the hunt for food, accompanied by privation and suffering, comes the feast to gorging. Theii* main evil was starvation, their good repletion. Even now the Esquimaux watches a seal-hole in the bitter cold for hours and days, and his compensation is the spearing and eating the seal. The good is resultant upon and in the long run I suppose, equivalent to the evil. These men look not back into the past, and forward into the future as w^e do. We, by extending our thought over a wider area, are led to more con- tinuing sacrifices, and aim at more lasting enjoyment in the result. The child suffers at school in order that his futui*e life may be more prosperous. The man spends the best part of his life in arduous toil, j)hysical or mental, in order that he may not want in his later years, or that his family may reap the benefit of his labour. Fiu'ther- seeing men spend their whole lives on work little remunerative that succeeding generations may be benefited. The prudent man transmits 294 Sir William B. Grove [April 20, health and wealth to his descendents, the improvident man poverty or gout. One main element of what we call civilisation is the capa- bility of looking further back into the past, and further forward into the future ; but, though measured on a different scale, the average antagonism and approximate equivalence appear to me to be the same. Can we suppose a state of things either in the inorganic or the organic world which, consistently with our experience or any deduc- tion di\awn from it, would be without antagonism ? In the inorganic world it would be the absence of all movement, or, what practically amounts to the same thing, movement of everything in the same direction, and the same relative velocity ; for, as movement is only known to us by relation, movement where nothing is stationary or moving in a different direction or with a different velocity would be unrecognizable. So in the organic but non-sentient world, if there wore no struggle, no absorption of food, no growth, nothing to overcome, there would be nothing to call life. If, again, in the sentient world there were no appetites, no hopes — for both these involve discontent — no fear, no good or bad, what would life be? If fully carried out, is not life without antagonism no life at all, a barren metajDliysical concej^tion of existence, or rather alleged conception, for we cannot present to the mind the form of such conception. In the most ordinary actions, such as are necessary to sustain existence, we find, as I have already pointed out, a struggle more or less intense, but we also find a reciprocal interdcj)endence of effort and result. The graminivorous animal is during his waking hours always at work, always making a small but continuous effort, select- ing his pastures, croj^ping vegetables, avoiding enemies, &c. The Carnivora suffer more in their normal existence ; their hunger is greater, and their physical exertion when they arc driven by hunger to make efforts to obtain food is more violent than with the Herbivora, if they capture their prey by speed or battle, or their mental efforts are greater if they capture it by craft. But then their gratification is also more intense, and thus there is a sort of rough equation between their pain and their pleasure, the more sustained the labour the more permanent is the gratification. As, with food or exercise, deficiency is as injurious in one, as is excess in another direction, so as affecting the mind of communities, as I have stated it to be with individuals, the effect of a life of ease and too much repose is as much to be avoided as a life of unremitting toil. The Pitcairn islanders, w^ho managed in some way to adapt their wants to their suj^j^ly and to avoid undue increase of poiDulation, are said never to have reached old age. In consequence of the un- eventful, unexcited lives they led, they died of inaction, not from deficiency of food or shelter, but of excitement. They should have migrated to England ! They died as hares do when their ears are stuffed with cotton, i. e. from want of anxiety. We have hope in our 1888.] on Antagonism. 295 suffering, and in tlio mid gusli of our i^leasure something bitter surges up. " We look before and after, and pine for what is not, Our sincerest laughter with some pain is fraught, Our sweetest songs are those which tell of saddest thought." The question may possibly occur to you, have we more or less antagonism now than in former times ? We certainly have more comjDlexity, more differentiation, in our mental characteristics, and probably in our physical, so far as the structure of the brain is con- cerned ; but is there less antagonism? With greater complexity come increased wants, more continuous cares. Higher cerebral development is accompanied with greater nervous irritability, with greater social intricacies — we have more frequent petty annoyances, and they affect us more. With all our so-called social improvements, is there not the same struggle between crime and its repression ? If we have no longer highway robberies, how many more cases of fraud exist, most of it not touched by our criminal laws ? As to litigation I am perhaps not an imj)artial judge, but it seems to me that if law w^ere as cheap as is desired, every next-door neighbour would be in litigation. It would seem as if social order had never more than the turn of the scale which is necessary to social existence in its favour when contrasted with the disorganizing forces. Without that there would be perpetual insurrections and anarchy. But though antago- nism takes a different form it is still there. Are wars more regulated by justice than of yore ? I venture to doubt it, though probably many may disagree with me. National self-interest or self-aggrandise- ment is, I think, the predominant factor, and is frequently admittedly so. I also doubt if the old maxim, " If you wish for peace prepare for war," is of much value. Large armaments and improvements in the means of destruction (whose inventors are more thought of than the discoverers of natural truths) are as frequently the cause of war as of its prevention. Are wars less sanguinary with 100-ton guns than with bows and arrows ? I cannot enter into statistics on this subject, but a sensible writer who has, viz. Mr. Finlaison, came to the conclu- sion that wars cease now as anciently, not in the ratio of the improve- ments in killing implements, but from exhaustion of men or means. Wars undoubtedly occur at more distant intervals, or the human race would become extinct. Probably the largely increased competition supi)lies their place : we fight commercially more and militarily less. It is a sad reflection that man is almost the only animal that fights, not for food or means of life or of perpetuating its race, but from motives of the merest vanity, ambition, or passion. War is, however, not wholly evil. It developes noble qualities — courage, endurance, self-sacrifice, friendship, &c. — and tends to get rid of the silly encum- brances of fashion and ostentation. But do the much bepraised inventions of peace bring less antagonism ? Consider the enormous labour and waste of time due to competition in the advertising system 296 Sir William B, Grove [April 20, alone. Paper-making, type-founding, printing, pasting, posting or otherwise circulating, sandwicli-men, &c., all at work for purposes which, I venture to think, are in great part useless ; and those who might add to the j)roductiveness of the earth, or to the enriching our knowledge, are helping to extend the limits of the black country/, and wasting their time in interested self-laudation. And the consumer pays the costs. "Buy my clothing, which will never w^ear out." " Become a shareholder in our company, which will pay cent, per cent." " Take my pills, which will cure all diseases," &c. These eulogies come from those highly impartial persons the advertisers, all promising golden rewards, but, as with the alchemists, on condition that gold be paid in advance for their wares; and the silly portion of the public (no small body) take them at their word. Though you may not fully agree with this my anathema of the advertising system, and though there may be some modicum of good in it, I thijik you will agree that it affords a notable illustration of antagonism. If I were a younger man, I think I should go to Kamchatka to avoid the penuy j^ost ; possibly I should not be satisfied when I got there. Civilisation begins by supplying wants, and ends by creating them, and each supj^ly for the newly created want begets other wants, and so on, " toties quoties." As far as we can judge by its present j)rogress, mankind seems tending to an automatic state. The requirements of each day are becoming so numerous as to occupy the greater portion of that day ; and when telegrams, telephones, electro-motion, and numerous other innovations which will probably follew these, reach their full development, no time will be left for thought, repose, or any spontaneous individual action. In this mechanical state of existence in times of peace, extremes of joy and sorrow, of good and evil, will become more rare, and the necessary uniformity of life will reduce passion and feeling to a continuous petty friction. The converse of the existence contemplated by the Stoics will be attained, and instead of a life of calm contemplation, our successors will have a life of objectless activity. The end will be swallowed up in the means. It will be all pursuit and no attainment. Is there sl juste miUeii,a point at which the superfluous commoda vitse will cease ? None probably would agree at where that point should be fixed, and the future alone can show whether the human race will emancij^ate itself from being, like Frankenstein, the slave of the monster it has created. In the cases I have given as illustrations — and many more might be adduced — the evil resulting from apparently beneficial changes is not a mere accident: it is as necessary a consequence as reaction is a consequence of action. In the struggle for existence or supremacy inevitable in all social growths, the invention, enact- ment, &c., intended to remedy an assumed evil will be taken advantage of by those for whom it is not intended ; the real grievance will have been exaggerated by those having an interest in trading on it, and the remedy itself will have collateral results not contemj^lated by those who introduce the change. I could give many instances 1888.] on Antagonism. 297 of this by my own experience as an advocate and judge, but this would lead me away from my subject. Evils, indeed, result from the very change of habit induced by the alleged im23rovement. The carriage, which saves fatigue, induces listlessness, and tends to prevent healthy exercise. The knife and fork save the labour of mastication, but by their use there is not the same stimulus to the salivary glands, not the full healthy amount of secretion, whereby digestion suffers ; there is not the same exercise of the teeth whereby they are strengthened and uniformly worn, as we see in ancient skulls. It seems not im- probable that their j^remature decay in civilised nations is due to the want of their normal exercise by the substitution of the knife and fork and stew-j^an. According to the evolution theory, our organs have grown into what they are by long use, and the remission of this tends to irregular development, or atroj^hy. Every artificial appliance renders nugatory some j)re-existing mode of action, either voluntary or involuntary ; and as the parts of the whole organism have become correlated, each part being modified by the functions and actions of the others, every part suffers more or less when the mode of action of any one part is changed. So with the social structure, the same correlation of its constituent parts is a necessary consequence of its growth, and the change of one part affects the well-being of other parts. All change, to be healthy, must be extremely slow, the defect struggling with the remedy through countless but infinitesimally minute gradations. Lastly, do the forms of government give us any firm ground to rest upon as to there being less undue antagonism in one than in another form ? Whether it is better to run a risk of, say, one chance in a thousand or more of being decapitated unjustly by a despot, or to have what one may eat or drink, or whom one may marry, decided by a majority of parish voters, is a question on which opinions may differ, but there is abundant antagonism in either case. Communism, the di'eam of enthusiasts, offers little prospect of ease. It involves an unstable equilibrium, i. e. it consists of a chain of con- nection where a defect in one link can destroy the working of the whole system, and w^hy the executive in that system should be more perfect than in others I never have been able to see. Antagonism, on the other hand, tends to stability. Each man working for his own interests helps to supply the wants of others, thus ministering to public convenience and order, and if one or more fail the general weal is not imperilled. You may ask, Why this universal antagonism? My answer is, I don't know; Science deals only with the How? not with the Why? Why does matter gravitate to other matter, with a force inversely as the square of the distance ? Why does oxygen unite with hydrogen ? All I can say is that antagonism is, to my mind, universal, and will, I believe, some day be considered as much a law as the law of gravi- tation. If matter is, as we believe, everywhere, even in the inter- planetary spaces, and if it attracts and moves other matter, which it Vol. XII. (No. 82.) x 298 Sir William E. Grove [April 20, apparently must do, there must be friction or antagonism of some kind. So with organized beings, Nature only recognizes the right, or rather the power, of the strongest. If twenty men be wrecked on a secluded island which will only suj^port ten, which tea have a right to the produce of the island ? Nature gives no voice, and the strongest take it. You may further ask me, Cui bono f what is the use of this disquisition ? I should answer, If the views be true, it is always useful to know the truth. The greatest discoveries have aj^peared useless at the time. Kepler's discovery of the relations of the i)lanetary move- ments ai)peared of no use at the time ; no one would now pronounce it useless. I can, however, see much probable utility in the doctrine I have advocated. The conviction of the necessity of antagonism, and that without it there would be no light, heat, electricity, or life, may teach us (assuming free will) to measure efibrt by the in-obable result and to estimate the degree of probability. It may teach us not to waste our powers on fruitless objects, but to utilise and regulate this necessity of existence ; for, if my views are correct, too much or too little is bad, and a due proportion is good (like many other useful things, it is best in moderation), to accept it rather as a boon than a bane, and to know that we cannot do good without effort — that is, without some suffering. I have si^oken of antagonism as jjcrvading the universe. Is there, vou may ask, any limit in point of time or sj)ace to force ? If there be so, there must be a limit to antagonism. It is said that heat tends to dissipate itself, and all things necessarily to acquii'c a uniform temperature. This would in time tend practically, though not abso- lutely, to the annihilation of force and to universal death ; but if there be evidence of this in our solar system and what we know of some parts of the universe, which probably is but little, is there no conceivable means of reaction or regeneration of active heat ? There is some evidence of a probable zero of temperature for gases as v^e know them, i. e. a temperature so low that at it matter could not exist in a gaseous form ; but passing over gases and liquids, if matter becomes solid by loss of heat, such solid matter would coalesce, masses would be formed, these w^ould gravitate to each other, and come into collision. It would be the nebular hypothesis over again. Condensations and collisions would again generate heat ; and so on ad infinitum. Collisions in the visible universe are probably more frequent than is usually supi)osed. New nebulfe appear where there were none before, as recently in the constellation of Andromeda. Mr. Lockyer, as I have said, considers that they are constant in the nebulae ; and if there be such a number of meteorites as are stated to fall daily into the atmosphere of this insignificant planet, what numbers must there be in the universe ? There must be a sort of fog of metaorites, and this may account, coupled with jDOssibly some dissipation of light or change of it into other forces, for the smaller degree of light than would be expected if the universe of stellar bodies were infinite. 1888.] on Antagonism, 299 For if so, and the stars are assumed to be of an equal average bright- ness, then if there be no loss or obstruction, as light from a star decreases as the square of the distance and would from an infinite number of stars probably increase in the same ratio, the night would be as brightly illuminated as the day. We are told that there are stars of different ages — nascent, adolescent, mature, decaying, and dying ; and when some of them, like nations at war, are broken up by collision into fragments or resolved into vapour, the particles fight as individuals do, and like them end by coalescing and forming new suns and planets. As the comparatively few people who die in London to-night do not affect us here, so in the visible universe one sun or planet in a billion or more may die every century and not be missed, while another is being slowly born out of a nebula. Thus worlds may be regenerated by antagonism without having for the time more effect ux^on the Kosmos than the people now dying in London have uj^on us, I do not venture to say that these collisions are in themselves sufficient to renew solar life; time may give us more information. There may be other modes of regeneration or renewed activity of the dissipated force, and some of a molecular character. The conversion of heat into atomic force has been sug- gested by Mr. Crookes. I give no opinion on that, but I humbly venture to doubt the mortality of the universe. Again, is the universe limited? and if so, by what? Not, I presume, by a stone wall! or if so, where does the wall end? Is space limited, and how? If space be unlimited and the universe of suns, planets, &c., limited, then the visible universe becomes a luminous speck in an infinity of dark vacuous space, and the gases, or at all events the so-called ether, unless limited in elasticity, would expand into this vacuum — a limited quantity of ether into an infinite vacuum ! If the universe of matter be unlimited in space, then the cooling down may be unlimited in time. But these are perhaps fruitless speculations. We cannot comprehend infinity, neither can we conceive a limitation to it. I must once more quote Shakespeare, and say in his words, " It is past the infinite of thought." But what- ever be the case with some stars and planets, I cannot bring myself to believe in a dead universe surrounded by a dark ocean of frozen ether. Most of you have read 'Wonderland,' and may recollect that after the Duchess has uttered some ponderous and enigmatical apophthegms, Alice says, " Oh ! " " Ah," says the Duchess, " I could say a good deal more if I chose." So could I ; but my relentless antagonist oj)posite (the clock) warns me, and I will only add one more word, which you will be glad to hear, and that word is — Finis. [W. R. G.] 300 Mr. James Wimsliurst [April 27. WEEKLY EVENING MEETING, Friday, April 27, 1888. William Huggins, Esq. D.C.L. LL.D. F.R.S. Vice-President, in the Chair. James Wimshurst, Esq. M.B.L Electrical Influence Machines. I HAVE the honour this evening of addressing a few remarks to you upon the subject of influence machines, and the manner in which I ju-oposc to treat the subject is to state as shortly as possible, first, the histori- cal portion, and afterwards to point out the prominent characteristics of the later and more commonly known machines. The diagrams upon the screen will assist the eye to the general form of the typical machines, but I fear that want of time will prevent me from explaining each of them. In 1762 Wilcke described a simple apparatus which produced electrical charges by influence, or induction, and following this the great Italian scientist, Alexander Volta, in 1775 gave the elcctro- phorus the form which it retains to the ju'esent day. This apparatus may be viewed as containing the germ of the principle of all influence machines yet constructed. Another step in the development was the invention of the doubler by Bennet in 1786. He constructed metal plates which were thickly varnished, and were supported by insulating handles, and which were manipulated so as to increase a small initial charge. It may be better for me to here explain the process of building up an increased charge by electrical influence, for the same principle holds in all of the mauy forms of influence machines. This Volta electrophorus, and these three blackboards, will serve for the purpose. I first excite the electrophorus in the usual manner, and you see that it then influences a charge in its top plate ; the charge in the resinous compound is known as negative, while the charge induced in its top plate is known as positive. I now show you by this electroscope that these charges are unlike in character. Both charges are, however, small, and Bennet used the following system to increase them. Let these three boards represent Bennet's three j^lates. To plate No. 1 he imparted a positive charge, and with it he induced a negative charge in plate No. 2. Then with plate No. 2 he induced a positive charge in plate No. 3. He then placed the plates Nos. 1 and 3 together, by which combination he had two positive charges within practically the same space, and with these two charges he induced a 1888.] on Electrical Influence Machines. 301 double cLargc in plato No. 2. This process was continued until the desired degree of increase was obtained. I will not go through the l^rocess of actually building up a charge by such means, for it would take more time than I can spare. In 1787 Carvallo discovered the very important fact, that metal plates when insulated, always acquire slight charges of electricity ; folio wiDg up those two imj^ortant discoveries of Bennet and Carvallo, Nicholson in 1788 constructed an apparatus, having two discs of metal insulated and fixed in the same plane. Then by means of a spindle aud handle, a third disc, also insulated, was made to revolve near to the two fixed discs, metallic touches being fixed in suitable positions. With this api^aratus he found that small residual charges might readily be increased. It is in this simple aj^paratus that we have the parent of influence machines (Diagram 1), and as it is now a hundred years since Nicholson described this machine in the Phil. Trans., I think it well worth showing a large sized Nicholson machine at work to-night. In 1823 Eonalds described a machine in which the moving disc was attached to and worked by the pendulum of a clock. It was a modi- fication of Nicholson's doubler, and he used it to supply electricity for telegraph working. For some years after these machines were invented no important advance appears to have been made, and I think this may be attributed to the great discoveries in galvanic electricity which were made about the commencement of this century by Galvani and Volta, followed in 1831 to 1857 by the magnificent discoveries of Faraday in electro-magnetism, electro-chemistry, and electro-optics, aud no real improvement was made in influence machines till 1860, in which year Varley patented a form of machine shown in Diagram 2. It also was designed for telegraj^h working. In 1865 the subject was taken up with vigour in Germany by Toei^ler, Holtz, and other eminent men. The most prominent of the machines made by them are figured in the Diagrams 3 to 6, but time will not admit of my giving an explanation of the many points of interest in them ; it being my wish to show you at work such of the machines as 1 may be able, and to make some observations upon them. In 1866 Bertsch invented a machine, but not of the multiplying type ; and in 1867 Sir William Thomson invented the form of machine shown in Diagram 7, which, for the purpose of maintaining a constant potential in a Leyden jar, is exceedingly useful. The Carre machine was invented in 1868, and in 1880 the Voss machine was introduced, since which time the latter has found a place in many laboratories. It closely resembles the Varley machine in appearance, and the Toepler machine in construction. In condensing this part of my subject, I have had to omit many prominent names and much interesting subject matter, but I must state that in placing what I have before you, many of my scientific friends have been ready to help and to contribute, and, as an instance 302 Mr. James Wimshurst [April 27, of this, I may mention that Professor Sylvanus P. Thompson at once placed all his literature and even his private notes of reference at my service. I will now endeavour to point out the more prominent features of the influence machines which I have present, and, in doing so, I must ask a moment's leave from the subject of my lecture to show you a small machine made by that eminent worker, Faraday, which, apart from its value as his handiwork, so closely brings us face to face with the imperfect apparatus with which he and others of his day miide their valuable researches. The next machine which I take is a Holtz. It has one plate revolving, the second plate being fixed. The fixed plate, as you see, is so much cut away, that it is very liable to breakage. PajDer in- ductors are fixed upon the back of it, while opj)osite the inductors, and in front of the revolving plate, are combs. To work the machine (1) a sj)®cially dry atmosphere is required ; (2) an initial charge is necessary ; (3) when at work the amount of electricity passing through the terminals is great ; (4) the direction of the current is apt to reverse ; (5) when the terminals are opened beyond the sparking distance the excitement rapidly dies away ; (6) it does not part with free electricity from either of the terminals singly. It has no metal on the revolving jjlates, nor any metal contacts ; the electricity is collected by combs which take the place of brushes, and it is the break in the connection of this circuit wliich supplies a current for external use. On this point I cannot do better than quote an extract from page 339 of Sir William Thomson's Paj^ers on Electrostatics and Magnetism, which runs : " Holtz's now celebrated electric machine, which is closely analogous in jDrinciple to Varley's of 1860, is, I believe, a descendant of Nicholson's. Its great power depends uj^on the abolition by Holtz of metallic carriers and metallic make-and-break contacts. It difl'crs from Varley's and mine by leaving the inductors to themselves, and using the current in the connecting arc." In respect to the second form of Holtz machine (Fig. 4) I have very little information, for since it was brought to my notice nearly six years ago I have not been able to find either one of the machines or any person who had seen one. As ^\ill be seen by the diagram it has two discs revolving in opposite directions, it has no metal sectors and no metal contacts. The " connecting arc circuit " is used for the terminal circuit. Altogether I can very well understand and fully appreciate the statement made by Professor Holtz in ' TJiJiwuiborn' s JonrnaV of May 1881, wherein he writes "that for the purj^ose of demonstration I would rather be without such machines." The first type of Holtz machine has now in many instances been made up in multiple form, within suitably constructed glass cases, but when so made up great difficulty has been found in keeping each of the many plates to a like excitement. When difierently excited the one set of plates furnished positive electricity to the comb, while 1888.] on Electrical Influence Machines. 303 the next set of plates gave negative electricity — as a consequence no electricity passed the terminals. To overcome this objection, to dispense with the dangerously cut j^lates, and also to better neutralise the revolving plate, throughout its whole diameter, I made a large machine having twelve discs 2 feet 7 inches in diameter, and in it I inserted plain rectangular slips of glass between the discs, which might readily be removed ; these slips carried the paper inductors. To keep all the paper inductors on one side of tl:e machine to a like excitement, I connected them together by a metal wire. The machine so made worked splendidly, and your late secretary, Mr. Spottiswoode, sent on two occasions to take note of my successful modifications. The machine is now ten years old, but still works splendidly. I will show you a smaller sized one at work. The next machine on which I make observations, is the Carre. It consists essentially of a disc of glass which is free to revolve with- out touch or friction. At one end of a diameter it moves near to the excited plate of a frictional machine, while at the opposite end of the diameter is a strip of insulating material, opposite which, and also opposite the excited amalgam plate, are combs for conducting the induced charges, and to which the terminals are metallically connected ; the machine works well in ordinary atmosphere, and certainly is in many ways to be preferred to the simple frictional machine. In my experiments with ii I found that the quantity of electricity might be more than doubled by adding a segment of glass between the amalgam cushions and the revolving plate. The current in this type of machine is constant. The Voss machine has one fixed plate and one revolving plate. UiDon the fixed plate are two inductors, while on the revolving plate are six circular carriers. Two brushes receive the first portions of the induced charges from the carriers, which portions are conveyed to the inductors. The combs collect the remaining portion of the induced charge for use as an outer circuit, while the metal rod with its two brushes neutralises the plate surface in a line of its diagonal diameter. When at work it supplies a considerable amount of electricity. It is self-exciting in ordinary dry atmosj)here It freely parts with its electricity from either terminal, but when so used the current frequently changes its direction, hence there is no certainty that a full charge has been obtained, nor whether the charge is of positive or negative electricity. I next come to the type of machine with which I am more closely associated, and I may preface my remarks by adding that the in- vention sprang solely from my experience gained by constantly using and experimenting with the many electrical machines which I possessed. It was from these I formed a working hypothesis which led me to make the small machine now before you. The machine is unaltered. It excited itself when new with the first revolution. It so fully satisfied me with its performance that I had four others 804 JJr. J. Wimshursi [April 27, made, the first of which I presented to this Institntion. Its eon- straction is of the simplest character. The two discs of glass revolve near to each other, and in opposite directions. Each disc carries metallic sectors ; each disc has its two brushes supported by metal rods, the rods to the two plates forming an angle of 90" with each other. The external circnit is independent of the brushes, and is formed by the combs and terminals. The machine is self-exciting under all conditions of atmosphere, owing probably to each plate being influenced by, and influencing in turn it-s neighbour, hence there is the minimum surface for leakage. When excited the direction of the current never changes ; this cir- cumstance is due probably to the circuit of the metallic sectors and the make-and-break contacts always being closed, while the combs and the external circuit are supplemental, and for external use only. The quantity of electricity is very large and the potential high. When suitably arranged the length of spark produced is equal to nearly the radius of the disc. I have made them from 2 inches to 7 feet in diameter, with equally satisfactory results. The Diagram Xo. 9 shows the distribution of the electricity npon the plate surfaces, when the machine is fully excited. The inner circle of signs corre- sponds with the elc<-tricity upon the front surface of the disc. The two circles of signs between the two black rings refer to the electri- city between the discs, while the outer circle of signs corresponds with the electricity upon the outer surface of the back disc. The diagram is the result of experiments which I cannot very well repeat here this evening, but in support of the distribution shown on the diagram I will show you two discs at work made of a flexible material, which when driven in one direction, close together at the top and bottom, while in the horizontal diameter they are repelled. When driven in the reverse direction the opposite action takes place. I have also experimented with the cylindrical form of the machine ; the first of these I made in 1882, and it is before you. The cylinder gives inferior results to the simple discs, and is more complicated to adjust. You notice I neither use nor recommend vul- canite, and it is perhaps well to caution my hearers against the use of that material for the purpose, for it warps with age, and when left in the daylight it changes and bc<:omes useless. I have now only to speak of these larger machines. They are in all respc-cts made up with the same plates, sectors, and brushes as were used by me in the first experimental machines, but for conve- nience sake they are fitted in numbers within a glass case. This machine has eight jdates of 2 feet 4 inches diameter ; it has been in the possession of the Institution for about three years. This large machine, which has been made for this lecture, has twelve discs, each 2 feet 6 inches in diameter. The length of spark from it is 13|^ inches. During the construction of the machine every care was taken to avoid electrical excitement in any of its parts, and after its comjdetion 1888.] on Electrical Influence Machines. 305 several friends were present to witness the fitting of the brushes and the first start. When all was ready the terminals were connected to an electroscope, and the handle was moved so slowly that it occupied thirty seconds in moving one-haK revolution, and at that point violent excitement appeared. The machine has now been standing with its handle secured for about eight hours ; no excitement is apparent, but still it may not be absolutely inert ; of this each one present must judge, but I will con- nerevent the different Spanish squadrons from joining, and where he found their ships, to destroy them. It was a grand and masterful stej), but it had scarcely been ordered before the Queen repented of it. Counter orders were sent post-haste to Plymouth, but Drake had already sailed. They followed him, but never found him ; perhaps the bearer of them was not too eager to find him. At any rate, Drake never got these orders, and acting on those first given, with which he had sailed, he did at Cadiz " singe the king of Spain's beard " in a most etFective manner. Thirty-seven ships there cojlected, were sunk, burnt, or brought away. They were as yet unarmed, unmanned, and, when' the forts were once passed, could offer no resistance. Other damao-e Drake did, insulting Santa Cruz in the very port of Lisbon, offerino- battle, which Santa Cruz was in no position to accept. Ships he had in numbers ; but they too were neither manned nor armed ; nor had he arms for them ; and though, with Drake off the mouth of the Tagus, the happy thought occurred to the authorities on shore to melt down the church bells, and make guns to di'ive him away before the guns were ready Drake had stretched off to the Azores' where he captured the San Pliilij:), a very large and rich East India- man, whose treasures are said to have first opened the eyes of our English merchants to the capabilities of Eastern trade, and to have led to thi foundation of the East India Company. The destruction of shipping and stores at Cadiz necessarily delayed the equipment of the Spanish fleet ; the year passed away, and it was not ready. The following February (1588) the Marquis of Santa Cruz died. The loss to Spain was incalculable, for he was the only man who by birth was entitled, and by experience was com- petent, to command such an expedition as that which he had set on foot. His name was encircled with a halo of naval victory. He had held a high command at the battle of Lepanto ; and in the action at Tercera was accredited with having put to ignominious flicrLt these very English who were now the object of attack. Curiously, how- ever, the king and his court do not seem to have realised their loss and with a light heart appointed Don Alonso Perez de Guzman ei 312 Professor J. K. Laughton [May 4, Bueno, Duke of Medina-Sidonia, to the vacant command. Medina- Sidonia, now in his thirty- eighth year, was a man with no qualifica- tion for the post except his distinguished birth and a gentleness of temper which, it was perhaj^s thought, would fit better with the idea of making him subordinate to the Duke of Parma. It had indeed appeared that Santa Cruz was not in the least disposed to accept this inferior part ; and it may very well be that the king was almost relieved by the solution of the difficulty which his death had offered. His successor was utterly ignorant of naval affairs, had but little expe- rience of military, and none whatever of high command. Personally brave, as became his long line of ancestry, he was, as a commander, by his total want of experience and knowledge, timid, undecided, and vacillating. His answer to the king on being ordered to take on himself the command is, in itself, a curiosity. The business, he wrote, was so great, so important, that he could not conscientiously undertake it, being, as he was, altogether without experience or knowledge of either the sea or of war.* His objections were, how- ever, overruled ; and in an evil hour for his reputation, he consented. The equipment of the fleet was pushed on, and by the middle of May it was ready to sail from the Tagus. It did actually sail on 20-30 May. I may here say that the name " Invincible," so commonly given to this fleet, was certainly not official. I know that, in common belief, it was given to it by the king himself. In Philip's numerous letters there is no trace of any such thing. By him, by his secretary, by Medina-Sidonia and other officers, the fleet is spoken of as the Grand Fleet — a name constantly used in England during the eighteenth century for what we would now call the Channel Fleet. In a semi- official list printed at Lisbon — a copy of which got into Burghley's hands, and is now in the British Museum — it is called " La felicissima Armada," the fortunate fleet ; but the term " Invincible " is unknown. It would seem probable that the name sprung out of the idle talk of some of the young adventurers — braggarts as became their age — or out of the silly gossip of the Lisbon taverns. None the less, however, the power and might of Spain were at this time so great, that when it was known they were being put forth to crush England, the thing was regarded as done. Anglia fuit was something like the expression of this general idea. Of the European opinion of the power of Spain at this epoch there is an admirable summary in the opening sentences of Lord Macaulay's ' Essay on the War of the Succession in Spain.' The Spaniard, he says, was, in the apprehension of our ancestors, " a kind of doBmon, horribly male- volent, but withal most sagacious and powerful." Their language is just such " as Arminius would have used about the Eomans." " It is the language of a man burning with hatred, but cowed by those whom he hates, and painfully sensible of their superiority, not only in power, but in intelligence." ♦ Duro, i. p. 415. 1888.] on the Invincible Armada : a Tercentenary Betrospect. 313 There was, however, one class of her Majesty's subjects, the members of which had not this exalted opinion of Spanish power or of Spanish prowess. For the last twenty years English sailors had been, in their own irregular way, fighting the Spaniards on every sea where they were to be met, and had come to the conclusion that, whatever the Spaniard might be ashore, afloat he was but a poor creature : the experiences of Drake, Hawkyns, Fenton, Fenner, and a score of others whose names are less familiar, had proved that even with great apparent odds in their favour, Spaniards were not invincible. Of all the panic-stricken accounts of the great Armada which have come down to us, it is well to point out that not one was written by a seaman, or by any one who had practical knowledge of the Spaniards by sea. You are all familiar with the exaggerations of contemporary historians. The Spanish ships were so huge that ocean groaned beneath their weight; so lofty, that they resembled rather castles or fortresses ; so numerous, that the sea was invisible, the spectator thought he beheld a populous town. What English sailors thought of them may be judged from a letter written by Fenner, who was with Drake when he burnt the shipping at Cadiz. " Twelve of her Majesty's ships," he said, " were a match for all the galleys in the king of Spain's dominions." But the power of SjDain, the tavern gossip and braggadocio of Lisbon, and the reports of spies who felt in honour bound to give full value for their hire, grossly exaggerated the size, the might, the armament and the equipment of the fleet as it sailed from Lisbon. Of the numbers, size, and armament I shall have to speak presently. The equipment, with which we are just now concerned, was so well arranged and so j)erfect, that by the time the fleet reached Cajje Finisterre vast quantities of the provisions were found to be bad, putrid, fit for nothing but to be thrown overboard. The ships were short of water, probably because the casks were leaky. The ships themselves were also leaking — strained, it was said, by the heavy weather, but really from being overmasted. Several of them were with difficulty kept afloat ; some were dismasted ; and the distress was so general that Mcdina-Sidonia determined to put into Corunua to refit. This he did, but without taking any precautions to let his intention be known through the fleet. The Scilly Isles had been igiven out as the rendezvous in case of separation, and some dozen of the ships, finding they had lost sight of the Admiral, did accordingly go to the neighbourhood of the Scilly Isles, where they were duly seen and reported at Plymouth. Their recall, the collecting the fleet at Corunna, the refitting, the reprovisioning, all took time. The damage was so great, the number of sick so large, the season getting so advanced, that a council of war urgently recommended postponing the expedition till the next year. The king's orders were, however, imperative ; and the fleet finally sailed from Corunna on the 12-22 July. The main part of the English fleet w^as meantime mustered at Plymouth under the command of Lord Howard of Effingham, the Vol. XIL (No. 82.) y 311 ProftssC'T J. K. Laughon [^'^7 ^j Lord- Admiral of England, with whom were Drake and Hawkyns as Tiee- and rear-admirals ; several noblemen, including Lord Thomas Howard, the admiral's nephew : his two sons-in-law. Lord Sheffield and Sir Eobert Southwell ; and that quaint mixture of courtier, adyenturer, and buccaneer, the Earl of Cumberland : together with many genuine sea-dogs, of whom the best known are Frobiser. Fenner, and Fen ton. Large numbers of merchants* ships, levied by the Queen or by their own towns, had joined the fleet, which as it lay at Plymouth consisted of about 80 sail all told. From the time of his return from the coast of Spain in the previous summer, Drake had been urgent that he should be sent out again, with a still more powerful squadron, to repeat the blow. Hawkyns, Frobiser, Fenner — all the seamen of experience — were of the same opinion. Howard, guided by their advice, repeatedly pressed the importance of the step ; but Elizabeth stead- fastly refused. She hoped, perhaps, for peace; more probably, perhaps, she hoped that the war might continue to be carried on in the same cheap and desultory fashion as during the last three years and was unwilling to set Philip the example of more sustained efforts. It is difficult to believe that she was entirely hoodwinked by the negotiations carried on in Flanders and by the false protestations of the Duke of Parma. She was herself too accomplishe»i in dissimula- tion to fall such an easy victim as she is commonly represented ; but I think that she had persuaded herself that the preparations in Spain were merely a threat, which, however, might be converted into a terrible reality. And this seems to me to explain her ignoble conduct in the matter of supplying the ships. She believed that the Spaniards would not be the aggressors ; that any extraordinary supply of ammunition was uncalled for, and provisions could bo put on board from week to week. It was cheaper, she may have argued to herself, than to buy and ship a quantity of stores which would only have to be landed again and disposed of at a loss. And so, notwithstanding the prayers and entreaties of Howard and Drake, backed up by the opinion of every man of experience, no further attempt was made on the Spanish ports. It is prolable enough that had Drake been permitted, he would have kindled such a blaze in the Tagus or in the harbour of Corimna, as would have effectually prevented the invasion which was now on foot. It has been said over and over again* that the Duke of Medina- Sidonia was ordered by Philip to hug the French coast, so as to avoid the English fleet and to reach the Straits of Dover with his force ir.tact. Xothing can well be more inaccurate. He was, on the contrary, orderel, if he met Drake near the mouth of the Channel, to fall on him and destroy him ; it would be easier and more certain to destroy the EngL'sh fleet piecemeal, than to allow it to collect ia one. Nor do his instructions contain one word about hugging the French coast ; on the contrary, they advise the Scilly Isles or the * MonBOD, in Chnrchill's ' Tovages,' iii. p. 149 : Lediard's ' Naval HMory,* p. 253. 1888.] on the Invincible Armada : a Tercentenary Metro^pect. 315 Lizard as a rendezvon?, and suggest the proprletr of seizing on some unfortified port in the Sonth of England.* As a matter of fact, a position south of the Scilly Isles was given out as a rendezvous in the first instance ; in the second, on sailing from Corunna, the rendezvous was Mount's Bay.+ In crossing the Bav of Biscay the Spaniards experienced bad weather, and were a gc-od deal scattered : barely two-thirds of the fleet were in company when Medina-Sidonia sighted the Lizard on the morning of 19 th July, acc-ording to the English calendar, which I shall henceforth follow. There, whilst waiting for the fleet to collect he hoists the royal standard at the fore — a sacred flag, containing in ad'iition to the royal arms, the figures of Our Lord and the Blesse-i Virgin. Other flags there were by the score. The fleet was organised by provinces ; and I am led to believe that the ships of each s«^uadr>:»n wore the flag of its province — Andalusia. Guipusc-oa, Xaples. Jrc. ; that they wore in addition the flags of the nobles and knights on board, and probably also the flag of the partictdar saint to which they were dedicated. But the flag which they appear to have worn in common as the flag of the empire was, strictly speaking, the Burgun- dian flag, which had been adopted by Spain in the time of Charles V. — white, a saltire raguled red. I may add that, amongst this great nmnber and diversity of flags, the one flag which was not worn and could not be worn was the red and yellow ensign of the preset] t day : this flag was not iu-vente-i till the year 17 So. I may here remind you, in puissing, that tLe English flag at this time was the plain St. George's flag — white, a cross red ; and this seems to have been worn by every English ship; though the ArJ:. Lord Howard's ship, flew the royal standard at the main — the lilies and lions, the relative pc»sition of which will recall to you the peculiar happines>s of Macaulay's cele- brated couplet : — " Lock how the lion of the sea lifts np his aiieient ctowil. And nnd-mtath his dea.ilv paw tr&ads the gay lilies down." Whether any of the ships flew private or local flags is doubtfnl. I think it, however, not improbable that they di'L Sir Oswald Brierly thinks that some of the ships may have worn, not the plain English flag, but the red cross on a Tudor ground, striped white and green, and has so shown it in some of his delightful pictures. That such a combination flag was occasionally used is pc>ssible enough, but I have not fuund any evidence of its having been worn as a national ensign at sea. Whilst the Dake of Medina-Sidonia was lying to, on the Lizard, on 19th July, he was sighted by one of the English cruisers, the Golden Hind, commanded by Thomas Flemyng, who forthwith carried the news to the Admiral ; 1 and, according to the familiar story, which I see no reason to doubt, found him, with the admirals * Duro, ii. p. S. t Ibid, ii. pp- 27, 1<>S. * 'State Papers,' Domestic, ccxv, 02. 316 Professor J. K. Laughtcm [May 4, and captains of tlie fleet, playing bowls on the Hoe. My friend, Mr. Wright, of Plymouth, the indefatigable secretary of the Tercen- tenary Commemoration, has called my attenion to a pamphlet first published in 1624, in which the incident is referred to as a well- known fact.* But the common idea that Flemyng was a pirate ; that he had been to sea pilfering ; j that in venturing into the presence of the Lord Admiral, he risked his life, and only saved it by the impor- tance of his news.i all this is contrary to well-ascertained fact. To say of Flemyng. or indeed of any seaman of that age, that he had not committed some irregularities which his enemies might stigmatise a.s piracy, is of course impossible ; but he was not a man of ill repute. He seems to have been a connection of Hawkyns,§ and certainly commanded the Golden Hind, a merchant-ship in the Queen's pay, and serving under the immediate orders of Drake. The following day, Saturday the 20th, the Spanish fleet was collected off the Lizard and moved slowly eastwards. A council of war was held. They had learned that the English fleet was at Plymouth, and the great weight of opinion among the Spanish leaders was that they ought to attack it there. It has always been said that Medina-Sidonia was prevented from doing this by his instruc- tions. The statement is inaccurate. The letter of his instructions distinctly permitted him to attack the English fleet ; the spirit cf them enjoined his doing it. j Fortunately he misunderstood his in- structions ; he conceived that he was bound to go up Channel, turn- ing neither to the right hand nor to the left until he could effect a junction with the Duke of Parma. Had he, on the 19th, when he first learned that the English fleet was at Plymouth, crowded sail with even such ships as he had with him, he might have entered the Sound that evening. The wind was from the south-west, and the English ships, penned in between the Spaniards and the shore, would have been forced to fight hand to hand ; the result might easily have been disaster. The Spaniards neglected their chance, and it never recurred ; for during the Saturday the English got out of the Sound, and stretched along the coast to the westward. On Sunday morniog, when the two fleets were first in presence of each other, the English were to windward, and by the weatherly qualities of their ships had no difficulty in keeping the advantage they had gained. And now, before the fighting begins, it is time to speak of the comparative force of the opposing fleets. "We have all known from our infancy that the Spanish ships, as compared with the English, were stupendous in point of size, marvellous in their strength ; in * 3Iorgan'= ' Phcenix Britanmcus." p. 345. t Monson, in ChurcMJl, iiL p. 150. + • "Westward Ho I ' § Wright's -Britain's Salamis,' p. 19. [i '• Si toparedes al dicho Draques con la Armada a la boca del Canal de Inglaterra, podreis en este caso enveatirle, porque si estan divididas sns fuerzas ser.'a mny bueno irlas venciendo asi, para que no se pndiesen juutor todas." — Duro, ii. p. 9. 1888.] on the Inline 'thle Armada : a Tercentenary BetrospecL 317 gnns and in number of men beyond all proportion. The numbers I give here, from tbe official Spanisb record,* agree very well with those reported in England.f 130 oT.S'jS 2Ao\ 1 8,050 Stamen. IS, 973 soldiers. 1,3S2 voluntters, &c 2, OSS rowers. Total .. 30,493 lu cue point alone of this statement is the diiierence from the English account worth noticing. Barrow gives the number of Spanish gims as 3165. To this I shall presently recur. Meantime, I have to point out to you that these numbers refer to the fleet as it left Lisbon. They had suffered a marked decrease before the fleet left Corunna, and a still further decrease before the fleet came into the Channel. Of the ships left behind I have no account. Some, and some large ships amongst them, certainly did not come on. Some, again, apj^ear to have parted company on the voyage : and of four galleys, from which much had been expected, one was driven ashore and wrecked near Bayonne ; the other three, making very bad weather of it, returned to Spain. i Allowing for these losses, I think it doubtful whether even 120 ships of all sizes came into the Channel; the nmnber of men did certainly not exceed 24,000 ; and in the council of war held at Corunna it was estimated as low as 22, 500. § On the other hand, the number of men borne in the English ships when ail collected together, is officially given as 15,925, to which ought to be added many more who were sent off from Plymouth on 21st July, or who joined as volunteers during the passage up Channel. It is difficult to estimate the gross total as less than from 17,000 to 18,000 men. Our idea of the size of the Spanish ships has been also somewhat exaggerated. According to Barrow : " The best of the Queen's ships placed alongside one of the first class of Spaniards would have been like a sloop-of-war by the side of a first rate." In point of tonnage, they were, in fact, the same. The largest Spaniard, the Be 6 6 1 3 8 12 8 14 6 "q 10 6 6 12 8 14 12 16 26 18 12 30 17 24 15 2 9 7 mentioned being described as "answerable to the pieces that are in the Mer Honour." I therefore show here also the armament of the Mer Honour, as given in the paper in the ' Archaiologia/ already referred to. Ship's Name. Tons. No. of Guns. Weight of Broadside in lbs. Description of Guns. I'ounders. Small Pieces 30 18 9 6 Mer Honour . . Sept. 1595 .. Oct. 1595, I. .. Do. II. .. 800 ? ? 41 44 44 36 281 299 282 222 4 4 15 16 20 16 18 20 12 4 4 4 8 2 2' Another estimate that seems entitled to credit, is that given of the armament of the Revenge — a ship of the same size and number of men as the Nonimreil, which was taken by the Spaniards in 1591, and was reported by them to have 43 brass guns ; 20 on the lower deck of from 4000 to 6000 lbs. weight, and the rest of from 2000 to 3000. t The greater weights correspond to the 60- 30- or 18-pounders, the smaller to the 9- and 6-pounders. Of the Spanish armament we cannot sj^eak with the same absolute knowledge ; but it seems admitted that the galeasses were the most 'State Papers,' Domestic, ccliii. 114; ccliv. 43. t Duio, i. p. 76. 320 Professor J. K. Laughton [May 4, heavily armed ships in the fleet ; and of these the San Lorenzo, which was taken off Calais, was the largest and heaviest. The report of her armament given by our people, who had possession of her for some time, corresj)onds fairly well with the official statement.* The Nuestra Senora del Bosario was the large ship captured by Drake and sent into Torbay-t Her armament is given from the official inventory taken at Torquay. She is spoken of by Duro as one of the most powerful and best ships of the fleet, f The other two ships do not seem distinguished in any way from others of the same size ; they belonged to the Levant squadron, and are classed with the San Juan de Sicilia of 800 tons and 26 guns, which is spoken of as having taken a prominent part in the action of 29th July. I have not met with any account of the armament of the sliij^s of the Portuguese squadron, including the San Martin, San Felipe, and San Mateo, of which all three were in the thickest of the tight, and the two last were driven on shore in a sinking state. Neither have I met with any inventory of the Nuestra Senora de la Eosa, the ship that was partially blown up, and was sent into Weymouth. I do not, of course, suppose that the more effective fighting ships of the fleet were armed like the Anunciada or Santa Maria de Vison ; but I do believe that the armament of these is a fair representative of that of a very large proportion of ships that have been counted as effective. I must note also, that whereas the Spanish ships of below 300 tons burden carried four or six small guns — a merely nominal armament — English ships of 200 tons carried a very respectable armament, and ships even still smaller were not altogether despicable. Of the way in which the English merchant ships were armed, we have no knowledge ; but considering that the fitting them out for purposes of war was no novelty, that many of them had probably been on privateering cruises before, and that the Pelican or Golden Hind, in which Drake went round the world — a ship of nominally 100 tons — had 14 guns, I would distinctly question Barrow's judgment that, "looking at their tonnage, two-thirds of them, at least, would have been of little, if any, service, and indeed must have required uncommon vigilance to keep them out of harm's way."§ They were not, indeed, the ships that were to be found in the fort-front of the fight — no more were the Eunjalus or Naiad at Trafalgar — but I see no reason to doubt that they did, in their own way, render good and efficient service. It was not only in the number and weight of guns that the English had a great comparative advantage ; they were immensely superior in the working of them. I may quote here from Captain Duro a very remarkable statement, which, however, is fully corroborated by original writers and by known facts. By the Spaniards, he says, || * ' State Papers,' Domestic, ccxiii. 67 ; Duro, i. p. 390. t ' State Papers,' Domestic, ccxv. 671. X Duro, i. p. SSn : " una de las mas fucrtes y mejores de la Armada.' § ' Life of Drake,' p. 270. |i Duro, 1. p. 77. J 1888.] on the Invincible Armada : a Tercentenary B^etrospect. 321 " the cannon was held to be an ignoble arm ; well enough for the beginning of the fray, and to pass away the time till the moment of engaging hand to hand, that is, of boarding. Actuated by such notions, the gunners were recommended to aim high, so as to dis- mantle the enemy and prevent his escape ; but, as a vertical stick is a difficult thing to hit, the result was that shot were expended harmlessly in the sea, or, at best, made some holes in the sails, or cut a few ropes of no great consequence." On the other hand, the gun was the weapon which the English sailors had early learned to trust to. Their practice might appear contemptible enough to an ExceUenfs gun's crew, but everything must have a beginning. With no disparts or side scales, with no aid beyond possibly a marked quoin to lay the gun horizontal, and with shot which — perhajDS a good inch less in diameter than the bore of the gun — wobbled from side to side, or from top to bottom, leaving the gun at any angle that chance dictated, the hitting the object aimed at was excessively doubtful. Still, by firing a great many shot, they did manage to get home with sufficient to do a good deal of damage. The Sj^anish accounts, speaking of the quickness of the English fire, estimate the English expenditure of shot as about three times their own.* Captain FitzGerald has recently called attention to the possibility of a rapid fire of small guns being found in the day of battle superior to the slow fire of big guns. It is a very grave question, and one that deserves all the care which Caj)tain FitzGerald can persuade our authorities to give it. But in the case we are now considering, the conditions were reversed ; it was the heavy armament which was quick firing, the lighter guns which were slow. There is another point which may very probably have also stood in the way of the Spanish gunners. Through the greater part of last century, the ports of Spanish line-of-battle ships were made much too small, with the idea, apparently, of keeping out the enemy's musketry shot, but with the actual result that their guns could neither be trained, depressed, or elevated. In this way was possible such an action as that between the Glorioso, a 70-gun ship, and the King George, a frigate-built privateer of 32 guns, in 1747 ; in which the two ships engaged broadside to broadside for several hours, without the privateer receiving any proportionate damage. f In the beginning, some such fault was general ; and to a very great extent, the gun was brought to bear by the action of the helm ; but it is at least probable that Spanish ships carried it to a still greater degree, and that this might, to some extent, exaggerate the badness of the Si^anish gunnery practice, which was very bad indeed. All this was quite well known to Philip, and therefore to the principal officers in the fleet before they left Lisbon. The king's instructions to Medina-Sidonia say : — " You are especially to take notice that the enemy's object will be to engage at a distance, on account of the advantage which they have from their artillery and * Duro, ii. 377. t ' Studies in Naval History,' p. 243. 322 Professor J. E, Laujliton [May i, the offensive fireworks with which they will be provided ; and on the other hand, the object on oiu* side should be to close and grapple and engage hand ti^ hand." * This perhaj^s may partly explain the com- paratively small quantity of shot per gun provided for such a vast imdertakiug; a quantity so small, that, notwithstanding the slowness of theii- fii-e, they ran short even after the skii-mishes in the Chanuel. In estimating the opposing forces, this great superiority of the English armament must be taken into account. Of Spanish shij^s of 300 tons and upwards, the number that left Lisbon was officially stated as 80 : but of thtse, 18 were rated as ships of bui-den [itrcas cle carper ; Fritsche's tin, which fell to powder when exposed to an exceptionally cold winter ; Gore's antimony ; Graham's palladium ; and allotropic nickel. It was further shown that metals could be obtained in chemically active states under the following conditions ; — Joule proved that when iron is released from its amalgam by distilling away the mercury the metallic iron takes fire on exposure to air, and is therefore clearly different from ordinary iron, and is, in fact, an allotropic form of iron. Moissan * has shown that similar effects are produced in the case of chromium and man- ganese, cobalt, and nickel, when released from their amalgams with mercury. Evidence is not wanting of allotroj^y in metals released from solid alloys, as well as from fluid amalgams with mercury. Certain alloys may be viewed as solidified solutions, and when such bodies are treated with a suitable solvent, usually an acid, it often happens that one constituent metal is dissolved, and the other released in an in- soluble form. Eeference was then made to a new alloy of potassium and gold, containing about ten per cent, of the precious metal. If a fragment of this alloy be thrown upon w\ater, the potassium takes fire, decomposes the water, and the gold is released as a black powder ; there is a form of this black or dark-brown gold which aj^pears to be an allotropic modification of gold, as it combines with water to form auric hydride. By heating this dark gold to dull redness, it readily assumes the ordinary golden colour. The Japanese use this gold, released from gold-copper alloys, in a remarkable way, for they produce, by the aid of certain pickling solutions, a beautiful patina on copi^er which contains only two per cent, of gold, while even a trace of the latter metal is sufficient to alter the tint of the patina. With regard to theoretical views as to molecular change in metals, special care was given to a description of the work of Professor W. Spring, of Liege, who had furnished much evidence in support of the view that polymerization of metals, that is the rearrangement of atoms in their molecules, could take place even in solid alloys of lead and tin. With reference to the passage of metals into allotropic states under slight external influences, it was stated that Debray t has * Comptes Rendus, vol. Ixxxviii. p. 180, 1879. t Ibid. vol. xc. p. 1195, 1880. 1888.] on some curious Projjerties of 3Ietals and Alloys. 369 given a case of an alloy in which a simple elevation of temperature induces allotroj^ic change in the constituent metals. It is prepared as follows : ninetj-five parts of zinc are alloyed by fusion with five parts of rhodium, and the alloy is treated with hydrochloric acid, which dissolves away the bulk of the zinc, leaving a rich rhodium- zinc alloy, containing about 80 per cent, of rhodium. When this alloy is heated in vacuo to a temperature of 400° C, a slight exjDlosion takes place, but no gas is evolved, and the alloy is then insoluble in aqua regia, which dissolved it readily before the elevation of temperature caused it to change its state. We are thus presented (as the experiment shown to the audience proved) with another undoubted case of isomerism in alloys, the unstable, soluble modifi- cation of the alloy being capable of passing into the insoluble form by a comj)aratively slight elevation of temperature. The industrial importance of the passage of metals and alloys into allotropic states, and the possibility of changing the mechanical properties of metals by apparently slight influences, was fully dealt with, and the lecture concluded with a detailed description of Pro- fessor Austen's own experiments w^hich have since been printed in the ' Philosoj)hical Transactions ' of the Royal Society, the results showing that very small amounts of metallic impurities exert an extraordinary effect on the tenacity and extensibility of gold, and that small as the amounts of these impurities are,. their influence is rigidly controlled by the Periodic Lawof Newlands and Mendeleef, the deleterious action of a metallic impurity being in direct relation to its atomic volume. The audience was asked " to remember that the knowledge of the kind of facts which had been considered comes to us from very early times, for the influence produced on metals by small quantities of added matter had a remarkable efi'ect on the development of chemistry, mainly by sustaining the belief of the early chemists in the possibility of ennobling a base metal so as to transmute it into gold. This was the object to which they devoted life and health, and laboured with fast and vigil. We inherit the results of their labours, and their prayers have been answered in a way they little anticipated, for, from an industrial point of view, if not from a scientific one, metals are " transmuted " by traces of impurity. Possibly we are nearing an explanation of the causes which are at work, but the fact remains that iron may be changed from a plastic material, which in ornament can be fashioned into the most dainty lines of flow, into one of great endurance, to which, for the present at least, the defence of the country may be trusted, apparently because armour-plates and missiles owe their respective qualities to the fact that carbon, manganese, and chromium have small atomic volumes." 370 General Monthly Meeting. [July 2, GENERAL MONTHLY MEETING, Monday, July 2, 1888. John Eae, ]\LD. LL.D. F.R.S. Vice-President, in the Cliair. A. Gordon Salamon, Esq. F.C.S. F.I.C. Thomas Graham Young, Esq. F.R S.E. were elected Members of the Eoyal Institution. The Special Thanks of the Members were returned for the following Donations to the Fund for the Promotion of Experimental Research : — Ludwig Mond, Esq £100 John Bell Sedgwick, Esq 25 Mrs. Bell Sedgwick 25 The Special Thanks of the Members were returned to Sir William Thomson for his valuable present of a set of three electric current measuring instruments (1) Magnetostatic milli-ampere meter; (2) Standard deci-ampere balance; (3) Magnetostatic deka-ampere meter. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — Accademia dei Lincei, Reale, Roma — Attie, ScrieQuarta: Rcndiconti. loSemestre, Vol. IV. Fasc. 5, 6. 8vo. 1888. American Association for the Advancement of Science — Proceedings, 36tli Meeting, New York, 1887. 8vo. 1888. Antiquaries, Society o/"— Archseologia, Vol. LI. Part 1. 4to. 1888, Proceedings, Vol. XII. No. 1. 8vo. 1888. Asiatic Society, Royal {China 5ranc70— Journal, Vol. XXII. Nos. 3, 4. 8vo. 1887. Astronomical 'Society, ij-oj/aZ— Monthly Notices, Vol. XLVIII. No. 7. 8vo. 1888. Bankers' Institute— J ourna\, Vol. IX. Part 6. 8vo. 1888. JBritish Architects, Royal Institute o/— Proceedings, 1887-8, Nos. 15, 16, 17. 4to. Buffalo Library — The Buffalo Library and its Building. With Views. 4to.j 1887. Chemical Society— J oMrnoX for June, 1888. 8vo. Crisjh Frank, Esq. LL.B. F.L.S. &c. M.R.I, (the Editor)— J omnal of the Royal Microscopical Society, 1888, Part 3. 8vo. Cutter, Ephraim, Esq.— The Clinical Morphologies. 8vo. 1888. Dax: Societe de jBon7a— Bulletin, Treizieme Anne'e, 2e Tremestrc. 8vo. 1888. 1888.] General Monthly Meeting. 371 Editors — American Journal of Science for June, 188S. 4to. Analyst for June, 1888. 8vo. Athenaeum for June, 1888. 4to. Chemical News for June, 1888. 8vo, Chemist and Druggist for June, 1888. 8vo. Engineer for June, 1888. fol. Engineering for June, 1888. fol. Horological Journal for June, 1888. 8vo. Industries for June, 1888. fol. Iron for June, 1888. 4to. Murray's INtagazine for June, 1888. 8vo. Nature for June, 1888. 4to. Kevue Scientifique for June, 1 888. 4to. Scientific News for June, 1888. 4to. Telegraphic Journal for June, 1888. 8vo. Zoophilist for June, 1888. 4to. Florence, Biblioteca Nazionale Centmle — Bolletino, Num. 58, 59. 8vo. 1888. Franklin Institute — Journal, No. 750. 8vo. 1888. Geneva: Societe de Phijsique et d'Hlstoire Naturelle — Memoires, Tome XXX. No. 4. 4to. 1888. Geograpliical Society, Royal — Proceedings, New Series, Vol. X. No. 6. Svo. 1888. Geological Institute, Imperial, Vienna — Verhandlungen, 1888, Nos. 7, 8. 8vo. Harlem, Socie'te Hollandaise des Sciences —Q^wYres Completes de Christiaan Huygens. Tome I. Correspondence, 1638-56. 4to. 1888. John Hopkins University — Taxation in American States and Cities. By R. T. Ely. 8vo. 1888. Linnean Society — Journal, No. 155. Svo. 1888. Manchester Geological Society — Transactions, Vol. XIX. Parts 18, 19. Svo. 1888. Manchester Steam Users' Association — Boilei:. Explosions Act, 1882. Board of Trade Reports, Nos. 187-223. fol. 1886-7. Meteorological 0^'ce— Quarterly Weatlier Reports, 1879, Part 3. 4to. 1888. Hourly'Reading, 1885, Part 3. 4to. 1888. Charts showing the Mean Barometrical Pressure over the Atlantic, Indian, and Pacific Oceans. 1888. Meteorological Society, Eoyal — Quarterly Journal, No. G6. Svo. 1888. Ministry of Public Works, Borne — Giornale del Genio Civile, Serie Quinta, Vol. II. No. 3. 8vo. And Disegni. fol. 1888. Neivall, Major-General D. J. F. R.A. (Jihe Author) — The Highlands of India. Svo. 1882. New York Academy of Sciences— Tvunsactions, Vol. VII. Nos. 1, 2. Svo 1887-8 Annals, Vol. IV. Nos. 3 and 4. Svo. 1888. Pennsylvania Geological Survey — Annual Report, 18S6, Part III. With Atlas. Svo. 1887. Western Middle Atlas, Part 2. Svo. 1887. Atlas, C 7. Svo 1887. Pharmaceutical Society of Great Britain — Journal, June, 1888. Svo. Photographic Society— J onvml, Vol. XII. No. 8. Svo. 1888, Preussische Akademie der Wissenschaften — Sitzungsbeiichte, I.-XX. Svo. 1888. Royal Society of London — Proceedings, No. 267. Svo. 1883. Royal Society of New South Wales — Journal and Proceedings, Vol XXI Svo 1888. Society of Arts — Journal, June, 1888. Svo. Tdegraph Engineers, Society o/— Journal, No. 73. Svo. 1888. Vereins zur Beforderung des Gewerhfleisses in Preussen — Verhandlungen 1888 Heft 5. 4to. ' Zoological Society of London — Proceedings, 1888, Part I. Svo. 1888. 372 General Moutlihj Meeting, Kov. 5 GENERAL MONTHLY MEETING, Monday, November 5, 1888. Sir James CiiicnTON BiiowxE, M.D. LL.D. F.R.S. Vico-Prcsidcut, iu the Chair. Amand Eouth, M.D. was elected a Member of the Royal Institution. The Special Thanks of the Members were returned for the foUowing Donation to the Fund for the Promotion of Experimental Research : — Lachhm Mackintosh Rate, Esq[ £50 The Special Thanks of the Members were returned to Messrs. Crossley for their valuable present of one of their Gas Engines (4 horse-power). The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FROM The Lords of the AdmiraUi) —QveenviicXi Ol^servations for 1S8G. 4to. 1888. Greenwich Spectroscopic and Fhotoijraphic Re.-nlts, 188G, 1887. 4to. 1886-7. Annals of the Cape Observatory, Vol. II. Tart 2. 4to. 1888. Cape Meridian Observations, 1882-1884. 8vo. 1887. The Governor-Genercd of India — Geological Survey of India : Records, Vol. XXI. Parts 2, 3. 8vo. 1888. TJie Secretary of State for India — Great Trigonometrical Survey of India, Vol. X. 4to. 1887. Catalogue of the Library of the India Office. 2 vol. 8vo. 1888. Meteorological Observations at Simla, 1841-5, Vol. II. 4to. 1877. Accademia dei Lincei, Reale, Roma — Atti, Serie Quarta ; ilendiconti. 1'' Semestre, Vol. IV. Fasc. 7-12. 8vo. 1888. Meraorie della Classe di Scienze Morali Storiclie e Filologiche. Serie 3*, Vol. XII. 4to. 1884. Atti, 1887. 4^ Serie, Vol. III. 4to. 1887. Academi/ of Natural Sciences, Philadelphia— Proceedings, 1888, Part 1. 8vo. 1888. American FMlosophical ^ociefy— Proceedings, No, 127. 8vo. 1888. Aristotelian Society — Proceedings, Vol. I. No. 1. 8vo. 1888. Asiatic Society of J5engaZ— Journal, Vol. LVI. Part 2, No. 4 ; Vol. LVII. Part 2, No. 1. 8vo. 1888. Proceedings, 1888, Nos. 2, 3. 8vo. Asiatic Society, Royal {China Branch)— 3 omnid, Vol. XXII. No. 5. 8vo. 1888. 1S88.] General Monthly Meeting. 373 Astronomical Society, /?o^aZ— Monthly Notices, Vol. XLVIII. Xos. 8, 9. 8vo. 1888. Australian Irrigation Colonies^ Commission— Australian Irrigation Colonies, fol. 1888. Australian Museum, Sydney — Eeport for 1887. fol. 1888. Bankers, Institute of — Journal, Vol. IX. Purt 8, 8vo. 1.^88. Boston Society of Natural Histo y — Memoirs. Vol. IV. Nos. 5, 6. 4to. 1888. British Architects, Boyal Institute of — Proceedings, 1887-8, Nos. 18 19, 20. 1888-9, No. 1. 4 to. Transactions, Vol. IV. 4to. 1888. British Association, Local Committee — Handbook to Bath. Edited by J. W. Morris. 8vo. 1888. British Museum — Catalogue of the Turkish Manuscripts. By C. Rieu. fol. ]888. Catalogue of Engraved Gems. 8vo. 1S88. British Museum (Natural History) — Catnlogue of Birds, Vol. XIV. 8vo. 1888. Catalogue of Fussil Reptilia and Ami)hibia, Part 1. 8vo. 1888, California, University of — Reports, Catalogue-", &c. 8vo. 1872-1888. Canada Geological and Natural Hi.^tory Survey — Catalogue of Canadian Plants. Part IV. By J. Macoun. 8vo. 1888. Annual Report, 183(3. Witli Maps. 8vo. 1887. Chambers, George F. Esq. F.H.A.S. M.B.I (the Author) — Local Government. 8vo. 1888. Cliemical Society —Journal for July-Oct. 1888. 8vo. Cliief Signal Officer, U.S. Army— Anniml Report for 1887, Part 1. 8vo. 1887. Churchill, Messrs. J. and A. (the Fidiliahers) — Journal of Laryngology and Rhinology, Vol. IL Nos. 8, 10, 11. 8vo. 1888. C^7?/o/Lonc^o*^ CoZ/f^e— Calendar 1888-9. 8vo. 1888.. Civil Engineers' Institution — Minutes of Proceedings, Vols. XCIII. XCIV". 8vo. 1887-8. Cornwall Polytechnic Society — Jubilee Reports, 1882. 8vo. Crisp, Frank, Esq. LL.B. F.L.S. &c. M.R.I, (the £'fZ/tor)— Journal of the Royal Microscopical Society, 1888. Parts 4, 5. 8vo. Dawson, Sir J. William, LL.D. F.E.S. (the Author) — Specimens of Eozoon Canarlense. 8vo. 1888. Dax : Society de B irda — Bulletin, Treizicme Anne'e, 3' Tremestre. 8vo. 1888. Devonshire Association fi>r the Advancement of Science, Literature, and Art — Report and Transactions, Vol. XX. 8vo. 1888. The Devonsliire Domesday, Part V. 8vo. 1888. E'ist India Association — Journal, 1888, Nos. ?,, 4. 8vo. Editors — American Journal of Science for July-Oct. 1888. 8vo. Analyst for July-Oct. 1888. 8vo. Athenagum for July-Oct. 1888. 4to. Chemical News for Julv-Oct. 1888. 4to. Chemist and Druggist for July-Oct. 1888. 8vo. Electrical Engineer for July-Oct. 1888. fol. Engineer for July-Oct. 1888. fol. Engineering for July-Oct. 1888. fol. Industries fcr July-Oct. 1888. fol. Iron for July-Oct. 1888. 4to. Murray's Magazine for July-Oct. 1888. 8vo. Nature for July-Oct. 1888. 4 to. Photographic News for July-Oct. 1888. 8vo. Revue Scientifique for Julv-Oct. 1888, 4to. Scientific News for Julv-Oct. 1888. 4to. Telegraphic Journal for July-Oct. 1888. 8vo. Zoophilist f( r July-Oct. 1888, 4to. Florence, Bihlioteca Nazionale Centrale — Bolletino, Num. GO-67. 8vo. 1388. Franldin Instdute — Journal, Nos. 751-754. 8vo. 1888. 374 General Monthly Meeting. [Nov. 5, Geographical Society, i?o//oZ— Proceedings, Xew Series, Vol X. Xos. 7-11. 8vo. 1888. Geologiral Inf^tifute, Tmperial, Vienna — Verhandluiis:eri, 1888, Xos. 9-12. 8vo. Jahrbueh. Band XXXVIII. Heft 1, 2. 8vo. 1888. Geological Society.— Qusirterly Journal, 1^0. 115. 8vo. 1888. Geological Society of Ireland,' Eoyal— Journal, Vol. XYII. Part 2. 8vo. 1887. GeorgofiU, Eeale Accademia — Atti, Quarta Serie, Vol. XT. Disp 2, 8. 8vo. 1888. Graifs Inn. The Honourahle Society of — Catalogue of tlie Libiaiy. By W. R. Douthwaite. 8vo. 1888. Hailem, Socie.e Hollandaise des Sciences — Aicbives Xeerlaudaises. Tome XXII. Liv. 4, 5. 8vo. 1888 Harris, George, Esq. LL.D. F.S.A. and Benjamin Ward Richardson, M.D. F.Ii S. — The Autobiography of George Harris. 8vo. 1888. Johris UojJciiis University — "University Circular, Xo.^. 66, 67. 4to. 1888. American Journal of Philology, Xo. 33. 8vo. 1888. American Ci eraical Journal, Vol. X Xo. 3. 8vo. 1888. Linnean Society— Journal. Xos. 119. 120, 131, 140, 1G3. 8vo. 1888. Transactions, Zoology Vol. III. Parts 5, 6 ; Botany Vol. II. Part 15, Vol. III. Part 1. 4to. 18St-8. Lishon Academy of Sciences-Jorna], Xo. 45. 8vo. 1887. A Electricidade. Por V. ]Ma(liado. 8vo. 18>'7. Liveing. G. I). Esq. M.A. F.BS. and Frofessor Dewnr, .17. J. FES. MEL {the Authors') — Spectrum of tbe Oxy-Hydrogeu Flume. (I'liil. Trans. Vol. 179.) 4to. 1888. Machintosh, IF. Esq. (the Translator)— The Gospel of St. Matthew in Pifian. 8vo. 1888. 3Iadras Government Central Museum — Catalogue of Batrachia Salientia and Apoda. By E. Thurston. Svo. 18S8. Manchester Geological Socitty— Transactions, Vol. XIX. Part 20. 8vo. 1888. Manchester Literary a)id Philosophical Socitty — Memoirs. Fourth Scries, Vol. I. 8vo. 1888. Mann, LLenry (the Author) — Features of Society in Old and in Xew England. 12mo. 1885. Mann. Mrs. E. J. (the Author) — Sketch of the Life and "Work of Robert James ^lann, M.D. ME.L 8vo. 1888. Maryland Medical and Chirurgical Faculty — Transactions, 1888. 8vo. Mechanical Engineers' Institution — Proceedings, 1888, Xo. 2. 8vo. Medical and Chirurgical Society, Eoyal — Proceedings, Xo. 19. 8vo. 1S88. Transactions, Vol. LXXI. 8vo. 1888. Menshruyghe, M. G. van der (the Author) — Causerie sur la tension superficiclle. Svo. 1888. Sur ma the'oiie du Filasre de I'Huile. 8vo. 1888. iUe^eoro7o(//caZ 0/nce— Atlantic Weather Cliarts, 1883. Part 4. 4to. 1888. Weekly Weather Reports, Vol. V. Xos. 20-38. 4to. 1888. Meteorological Society, Eoyal — Quarterly Journal, Xo. 61. 8vo. 1888. ^leteoiological Record, Xo. 28. Svo. 1888. Miller, IF. /.C. £"6^7. (Z/te 7?e5r«Vfrar)— The Medical Register. Svo. 1888. The Dentists' Register. Svo. 1888. Ministri/ of Public Worhs, Eome —Giornale del Genio Civile, Serie Quinta, Vol. li. Xos. 5, 6. Svo. And Disegni. fol. 1888. Mnsif-al Associcdion — Proceedings, 4th Session, 1887-8. Svo. Aeic S'luth Wahs^ Aqent-Gener(d — The History of Australian Exploration, 1788- 1888. Bv E. Favenc. Svo. 1888. Numismatic Society— Chro\dcle and Journal, 1888, Part 2. Svo 1888. Odontological Society of Great Britain — Transactions, Vob XX. Xo. 8. Xew Series. Svo. 1888. Pharmaceutical Society of Great Britain — Journal, Jnlv-Oct. 18S8. Svo. Photographic Society— J omna.], Vr.l. XII. Xo. 9 ; A'ol. XIII. Xo. 1. Svo. 1888. Physical Society of London— Procecdiug-, Vol. IX. Parts 3, 4. Svo. 1888. 1883.] General 2Ionthly 3Ieeting. 375 Richardson, B. W. M.D. F.R.S. (the Author)— The Asclepiad, Vol. Y. No. 19. 8vo. 1888. Eio de Janeiro O&seri-a/or?/— Kevista, Nos. fi, 8, 9. 8vo. 1888. Aniiales, Tome III. Passage de Venus, 1882. 4to. 18S7. lioyal College of Surgeons of England — Calendar, ISSS. 8vo. lioyal College of Surgeons in Ireland — The Medical Profession, 1887. Carmicbael Prize Essays by W. Ptivington and T. Laft\in. 2 vol. 8vo. 18S8. Boyal Dublin Society— Tnmsdctions, Vol. III. Xo. 14; Vol. IV. No. 1. 4to. 1887-8. Proceedings, Vol. V. Parts 7, 8; Vol. VI. Parts 1, 2. 8vo. 1887-8. Boyal Society of Canada — Proceedings and Transactions, Vol. V. 4to. 1887-8. Boyal Society of London — Proceedings, Nos. 268-271. 8vo. 1888. Boyal Society of Tasmania — Proceedings for 18S7. 8vo. 1888. Saxon Society of Sciences, Boyal — Mathematisch-ph3-sisclie Classe : Abliandluns:. Band XiV. No. 9. 8vo. 1888. Philologisch-historiscben, Classe: Abliandlungen, B.md X. No. 9; Band XT. No. 1. 8vo. 1888. Seismological Society of Jajjan — Transactions, Vol. XII. 8vo. 1888. Siemens, Alexander, Esq. M.B.I. ( for the Executors) — Ti.e Life of Sir William Siemens. Bv W. Pole. 8vo."l888. Smith, Basil JVoodd. Esq. .Ui?.f.— Middlesex C-amty Records, Vol. III. 8vo. 1888. Smithsonian Institution — Smithsonian Mi.cdlaneous Culleciious, Vols. XXXII. XXXIII. 8vo. 1888. Report. 1885, Part 2. 8vo. 1886. Society o/^r^s— J. ainiah July-Oct. 1888. 8vo. Society of Dilettanti — The Principles of Athenian Architecture. By F. C. Penrose. New Edition, fol. 18S8. Statistical Society— J ouythxI, Vol. LI. Parts 2, 3 8vo. 1888. St. Petersbourg, Academie Impe'riale des Sciences — Memoires, Tome XXXVI. Nos. 1, 2. 4to. 1888. Bulletin, Tome XXXIL Nos. 2, 3, 4. 4to. 1888. Telegraph Engineers, Society of — Jcurnal, No. 74. 8vo. 1888. United Service Institution, Boyal — Journa', No. 144. 8vo. 1888. United States Xal•y~^YilV Series, Nos. I. II. III. 8vo. 1885. General Information Series, Nos. III. IV. VI. VII. 8^0. 1884-8. Coaling, Dockhig, &c. of the Ports of the World. 8vo. 1888. Vereins zur Beforderung des Geicerbfieisses in Preussen — Verhandlungen, 18S8 : Heft 6, 7, 8. 4to. Victoria Institute — Transactions, Nos. 85, S6. 8vo. 1S8S. Wemyss. the Earl of (the Author) — Socialism at St. Stephens^ 18S6-7. 16mo. 1888. Wild, Dr. H. (the Director)— Repertorinm fiir INIeteornlogie, Band XI. 4to. 1888. Zoological Society of London — Proceedings, 1888, Pai'ts 2, 3. 8vo. 1888. 376 General Monthly/ Meeting. [Dec. 3, GENERAL MONTHLY MEETING, Monday, December 3, 1888. Sir James Crichton-Buowne, M.D. LL.D. F.R.S. Yicc-Presulent, in the Chair. William Dunsmore Bohm, Es*^. Rev. Henry Thomas Cart, M.A. Mrs. Charles Daniell, Josiah Goodall, Esq. Miss C. Naden, Benjamin Ward Richardson, M.D. F.R.S. Colonel T. E. Teuuant, were elected Members of the Royal Institution. The Special Thanks of the Members were returned for the following Donations to the Fund for the promotion of Experimental Research : Mrs. R. J. Mann (for the late Dr. R. J. Mann, i\I.R.L) .. £20 Mrs. Bloomfield Moore £50 Warren De la Rue, Esq £100 The following Lecture Arrangements were announced : — Professor Dewar, INI. A. F.R.S. M.R.I. Fullerian Professor of Chemistrj^ R.I. Six Lectures (adapted to a Juvenile Auditory) on Clouds and Cloudland. On Dec. 27 (nursday), Dec. 29, 1888; Jan. 1, 3, 5, 8, 1889. George John Romanes, Esq. M.A. LL.D. F.R.S, M.E.I. Fullerian Professor of Physiology, R.L Twelve Lectures, constituting the second part of a Course on Before and After Darwin (The Evidences of Organic Evolution, and the Theory of Natural Selection). On Tuesdays, Jan. 22 to April 9. Professor J. W. Judd, F.R.S. Four Lectures on The Metamorphoses of Minerals. On Thursdays, Jan. 24, 31, Feb. 7, 14. Sidney Martin, M.D. F.R.C.S.E. B.Sc. Four Lectures on The Venom of Serpents and Allied Poisons, including those used in the Middle Ages. On Tlinrsdays, Feb. 21, 28, March 7, 14. J. Henry Middleton, Esq. M.A. Slade Professor of Fine Art in the University of Cambridge. Four Lectures on Houses and their Decoration from the Classical to the Medleyal Period. On Thursdays, March 21, 28, April 4, 11. Professor Ernst Pauer. Four Lectures on The Character of the Great Composers and the Characteristics of their Works (with Illustratiuns on the Pianoforte). On Saturdays, Jan. 2i3, Feb. 2, 9. 16. The Right Hon. Lord Rayleigh, M.A. D.C.L. LL.D. F.R.S. M.B.I. Pro- fessor of Natural Piiilosophy, R.L Eight Lectures on Experimental Optics (Polarization; Wave Theory). On Saturdays, Feb. 23 to April 13. 188H.] General Monthly Meeting. 377 The Pkksents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FEOM The Lords of the Admiralty —y^nuticdl Aluiautic for 1«9*2 8vo. 1888. Accademia dei Lincei, Beale, Boma — Atti, Serie Quarta : Kendiconti. 1« Semestre, Vol. IV. Fasi'. 13 ; 2o Semestre, Vol. IV. Faso. 2, 3, 4, 5. 8vo. 1888. Agricultural Society of England. Boyal — Journal, Vol. XXIV. Part 2. 8vo. 1888. Amsterdarii Societe Royale de Zoologie — Byflragen tot de Dierkiinde. Afl. 14, 15, 16. 4to. 1888. Feestnummer. 4to. 1888. Antiquaries, Society of — Proceediugs, Vol. XII. No. 2. 8vo. 1888. Asiatic Society of Bengal -J ournu], Vol. LVII. Part 1, Nos. 1, 2; Vol. J>VII, Part 2, Nos.'2, 3. " 8vo. 1888. PreceediDgrf, 1888, Nos. 4-8. 8vo. Bankers' Institute — Journal, Vol IX. Part 9. 8vo. 1888. Bassett, A. B. Esq. M.A. M.R.I, (the Author) — Treatise on Hv(lrodvn;uuics, Vol. II. 8vo. 1888. British Architects, Boyal Institute of — Proceedings, 1888-9, Nos. 2, 3. 4to. Kalendar, 1888-9. ' 8vo. Canada Meteorological Service — Report, 1885. 8vo. 1888, Chemical Society — Journal for November, 1888. 8vo. Dance, Henry A. Esq. — Diceionario Mallorquin-Castellano-Iiatin, Por J. J, Amengual. 2 vols. 4to. Palma, 1858-78. Missae Golhicse et Officii Muzarabiea. 4to. Toleti. 1875, La Roqueta, 1887. 4to. Palma, 1887. Editors — American Journal of Science f*.>r November, iS^S. 8vo, Anal^^st for November, 1888, 8vo. Athenaeum for November, 1888. 4to. Chemical News for November, 1888. 4lo. Chemist and Druggist for November, 1888. 8to, Engineer for November, 1888. fol. Engineering for November, 1888. fol. Industries for November, 1888. fol. Iron for November, 1888. 4to, Murray's Magazine for November, 188s. 8to. Nature for November, 1888, 4to. Revue Scientifique for November, 1888. 4to. Scientific News for November, 1888. 4to. Telegraphic Journal for November, 1888. 8vo. Zoophilist for November, 1888. 4to. Florence, Biblioteea Xazionale Centrale — Bolletinu. Num. 68, 69. 8vo. 1888. Geological Institute, Imperial, Vienna — Verhandlungen, 1888, No, 13. 8vo. Geological Society— Q,UB.Tier\y Journal, No. 176. 8vo. 1888. Glasgow Philosophical Society — Proceedings, Vol. XIX. 8vo. 1888. Gordon, Surgeon- General C. A. M.D. C.B. M.R.I, (the Author')— The A'ivisection Controversy in Parliament. 8vo. 1888. Harlem, Societe Hollandaise des Sciences — Archives Neerlandaises, Tome XXIIl. Liv. 1, 8vo. 1888, Longstaf, LI. W. Esq, F.R.G.S. M.B.I. (Vie Author)— ^otes on the Wimbledon >ree Public Library. 8vo. 1888. Madras Government Central Museum — Report, 1887-8. foL Catalogue of Coins, No. 2. By E, Thurston. 8vo. 1888, Meteorological Office— Hourly Readings, 1885, Part 4. 4to. 1888. Meteorological Observations at Stations of the Second Order for 1884. 4to. 1888. Contributions to the Knowledge of the ISleteorology of the Arctic Regions, Part 5. 4to. 1888. Ministry of Public Works, i2o f«e—Giornale del Genio Civile, Serie Quinta, Vol. II, Nos. 7, 8. Svo, And Disegni. fol, 1888. Vol. XII. (No. 82,) 2 c 378 General Monthly Meeting. [Dec. 3, J 888. Midi, Matthias, Esq. (Jht J. u^Ao/-)— Supplementary Notes, ka. to the Plav of Hamlet. 8vo. 1888. North of Enqland Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVII. Fart 5. 8vo. 1888. Numismatic Society — Chronicle and Journal, 1888, Part 8. 8vo. 1888. Odontological Society of Great Britain — Transactions, Vol. XXI. No. 1. New Series. 8vo. 1888. Perry, Rev. S. J. F.R.S. {the Author) — Results of Meteorological and IMagnetical Observations, 1887. 12mo. 1888. Pharmaceutical Society of Great Britain — Journal. November, 1888. 8vo. Richardson, B. W. M.D. F.R.S. M.R.L {the Author)— The Asclepiad, Vol. V. No. 20. 8vo. 1888. Rio de Janeiro Observatory — Revisfa, No. 10. 8vo. 1888. Royal Institution of Cornwall — Jouinal, Vol. IX. Parts 1, 2, o. 8vo. 1886-8. St. Petershourg, Academic Imperiale des Sciences — Memoires, Tome XXXVI, Nos. 3-5. 4to. 1888. Society of Architects — Proceedings, Vol. I. Nos. 1, 2. Svo. 1888. Sonety o/ .4 rfs— Journal, November, 1888. 8vo. Surgeon- GeneraVs Office, U.S. Army — Index Catalogue of the Librarv, Vol. IX, 4to. 1888. Teyler Museum— Archives, Serie II. Vol. III. 2^ Partie. 4to. 1888. Catalogue de la Bibliotheque. Liv. 7, 8. 4to. 1887-8. United Service Institution, Royal — Journal, No. 145. 8vo. 1888. United States Geological Survey — Monographs, Vol. XII. Geology and Mining Industry of Leadville, Colora lo, With Atlas. 4to and fol. 1883-6. ISocal Institution of Q^xmt iSritatm WEEKLY EVENING MEETING, Friday, January 25, 1889. Colonel J. A. Grant, C.B. C.S.I. F.E.S. Vice-President, in the Chair. Professor G. H. Darwin, M.A. LL.D. F.R.S. M.B.L Meteorites and the History of Stellar Systems.^ The great advances which have been recently made in the art of celestial photography have now made it possible to study the details of structure of some of the nebulae, which formerly only ap23eared as a chaotic luminosity, even when viewed through a powerful telescope. To illustrate this new method of research, a photograph of the great nebula in Andromeda, by Mr. Isaac Eoberts, was exhibited ; it showed that the nebula consists of a bright central condensation, surrounded by several faintly luminous concentric rings. A short sketch of the Nebular Hypothesis of Laplace and Kant was then given. This is a mechanical theory of the evolution of a nebula into a star with attendant planets. It was then pointed out that Mr. Roberts's photograph exhibits exactly the condition which Laplace imagined, and it thus confirms the substantial truth of his hypothesis. But many points in the evolution of a planetary system are still involved in much obscurity, and there is in particular one difficulty, so fundamental that some astronomers have been led by.it virtually to throw over the nebular hypothesis. That theory attributes the annulation of the nebula to the gradual diminution and ultimate vanishing of gaseous pressure at the equator of a rotating mass of gas. Thus it is the very essence of the hypo- thesis that the nebula should consist of continuous gas. Now there is in the solar system at present no trace of the all- pervading gas from which it is supposed to have been evolved, whilst there is much evidence that the space surrounding the sun and planets is peopled by countless loose stones or meteorites flying about in various directions. This latter view is confirmed by the recent spectroscopic researches of Mr. Lockyer, who has been led to suggest that the luminous gas, which undoubtedly forms the visible portion of nebulfe, is gas vola- tilised from the solid state, and rendered incandescent by violent impacts between meteoric stones. These gases, he says, cool quickly, cease to be luminous and condense, but the collisions being incessant, the whole nebula shines with a steady light. * See Phil. Trans, R.S. vol. 180a (18S9). pp. 1-69. Vol. XII. (No. 83.) 2 d 380 Professir G. H. Danrin [Jau. 25, It appears, then, to be probable that the immediately antecedent state of the sun and planets was not a continuous gas, but was a swarm of loose stones. Here, then, there arises a dilemma ; for on the one hand the meteoric theory denies the continuity of the matter forming nebulae, whilst on the other hand the nebular hypothesis demands such continuity. The object of this lecture was to show that there is, however, a wav in which these two apparently conflicting ideas may be reconciled. In order to prepare the way for the suggested reconciliation, a sketch was then given of the Kinetic Theory of Gases, according to which a gas consists of a great number of elastic molecules, moving at high speed in all directions at hazard, and continually coming into collision with one another by chance. According to this theory a pigmy, of a size comparable with the average distance between adjacent molecules, would be conscious of the blows he received from individual molecules, and he would have lost the sense of gaseous pressure, which arises from impacts too numerous and too rapid for discrimination. Thus, what is called gaseous pressure is a question of the magnitude of the observer. The suggestion, then, of this lecture was that celestial nebulae are of such large dimensions, that meteorites might be treated as mcdecules and that their collisions might impart to a nebula, as a whole, the quasi- gaseous mechanical properties demanded by the nebular hypothesis. But if such a suggestion is to rise above the level of mere con- jecture, it demands a careful examination in detail. It is accordingly necessary not only to consider the details of an individual collision, but also to examine whether a meteoric medium is of sufficiently fine texture to fulfil the conditions imputed to it. The kinetic theory of gases requires that the molecules of gas should be perfectly elastic, and, although meteorites are certainly not perfectly elastic, it was maintained that the sudden volatilisation of gas, at the point of contact of two of them at the moment of collision, would act as a violent explosive between them, and would impart to them a virtual elasticity of considerable perfection. The investigation of the degree of fineness of grain necessary to admit the applicability of the theory involved numerical calculation, and the requisite data had necessarily to be derived from the solar system. If the sun's mass were broken up into iron meteorites, each weighing say a pound, the dimensions of each meteorite would be known, and their number would be four followed by thirty zeros. These iron stones were then supposed to be distributed in a swarm extending beyond the present orbit of the planet Xeptune. To give numerical precision, the swarm was taken to extend as far beyond Neptune as Saturn now is from the Sun. These supposed conditions were adopted merely by way of an example which should represent a nebula of extreme tenuity ; fur if the meteorites were not too sparsely distributed to impart quasi-gaseous 1889.] on Meteorites and the History of the Stellar Systems. 381 properties to the whole in this supposed case, the nebiiLa would a fortiori possess those properties when it had shrunk to smaller dimensions. The swarm was supposed to be arranged in a perfect sjihere, and what may be described as the layers of equal density of population were taken to be concentric spheres, but the density of population would necessarily be much greater towards the middle than towards the outside. The whole crowd of stones would arrange itself automatically into a steady condition, in which the population had no tendency to shift, although, of course, the dance and collisions between the constituents of the crowd would be incessant. When this steady condition was sub- mitted to calculation, it was possible to discover the average velocity of the stones, the average density of population, and the average frequency of collision at each point of the swarm. It will naturally occur to the reader to inquire as to the source of the great velocity of the stones ; it arose from gravitation, the stones having fallen in from a great distance towards a centre of aggregation. If somewhere in space there were an aggregation of meteorites, and if a stone were released from a state of rest at a very great dis- tance, it would fall towards the swarm under the influence of gravi- tation. On reaching the swarm it would have acquired a certain velocity, and would penetrate to some uncertain distance, until it happened to strike another stone. Henceforth its path would be zigzag, as it happened to strike, and it became incorporated as a member or molecule of the swarm. The supposed visitant from outside space imported energy of motion into the swarm, and besides increased the total mass of the swarm. Thus, if it be imagined that the swarm is increased by the addition of stone after stone, each being let fall from a distance, it is clear that, in the course of accretion, the energy of agitation of the meteorites continually increases. When stones have ceased to fall in, the materials of the nebula were collected, and by means of incessant collisions the swarm gradually attained the steady condition above referred to. By reasoning of this kind it was possible to discover how fast the stones were moving, but it is proper to add that an important correction had to be applied to allow for the fact that at each collision between two stones some speed is lost. In the process of settling down into the steady condition, each stone loses, by imperfect elasticity, three- tenths of the speed it would have if it were a fresh arrival from space. It makes no material difference in the result by whatever process the stones were collected together, and the account given above of the formation of a swarm was not intended as a contribution to its history, but was only meant to explain the mechanical principles involved. By this line of argument it may be concluded that when the solar swarm extended half as far again as the planet Neptune, the average velocity of the stones was three miles a second. 2 D 2 382 Prufessor G. E. Darwin [Jan. 25, It was next necessary to find out how often the stones came into collision, how far they travelled from one collision to the next, and whether the collisions could be frequent enough to impart to the whole nebula the gaseous property demanded by the nebular hypothesis. Even a microscopic animal in our atmosphere is not aware of the individual impacts of molecules on his body, and his sensation is still that of gaseous pressure. Bat it must clearly be a giant who would not be aware of the individual blows of meteorites in a meteoric nebula, but would only realise their average effects. It would not be easy to explain the exact reasoning by which it is possible to determine how large the giant must be in order to act as a judge of the gaseous property of the meteoric swarm, nor of how a comparison of his dimensions with the texture of a meteoric swarm is to be made, and it must suffice to say that the comparison is best clothed in a form which may appear something quite different, but which is really substantially the same. It may be stated, then, that a meteoric nebula would behave suffi- ciently like a gas to allow the nebular hypothesis to be true, if the average path of a meteorite between two collisions were only a short portion of that curved orbit which it would describe under the action of gravitation if it could move through the swarm without ever colliding with another stone. These explanations led on to the numerical values derivable from calculation, on the hypothesis that the solar nebula, consisting of 1 lb. iron stones, was distributed in a swarm extending half as far again as the present distance of the planet Neptune from the Sun. It appeared, then, that at the middle of the swarm a meteorite would, on the average, come into collision every 13 hours, and would travel 140,000 miles between collisions ; at the distance of the small planets called the asteroids, it would collide every 17 hours, and would travel 190,000 miles between ; at the distance of Uranus the collisions would be at intervals of 25 days, and the path 6,000,000 miles ; and lastly, at the distance of Neptune, the interval would be 190 days, and the path 28,000,000 miles. It may also be show^n that the path described between collisions forms a larger portion of the whole curved orbit of a meteorite the further we go from the middle of the swarm. Even at the distance of the planet Neptune the collisions were, relatively speaking, so frequent that, on the average, gravity only sufficed to draw the meteorite aside from the straight path by l-66th of the length of path it had traversed, before it was deflected into a fresh orbit by collision with another stone. The fraction 1-6 6th was then the numerical value of the criterion of the aiDplicability of quasi-gaseous properties to the swarm, and this fraction is so small that it may be concluded that the swarm passes the proposed test. It followed, therefore, that if meteorites possess a virtual elasticity, a swarm of meteorites provides a gas-like medium of fine enough structure to satisfy the demands of the nebular hypothesis. 1889.] on Meteorites and the History of the Stellar Systems. 383 The result of tliis discussion then appeared to justify the opinion that the meteoric theory may be reconciled with Laplace's hypothesis, and that they may both be held to be true. After this discussion of the proposed modification of Laplace's hypothesis, it was natural to turn to the series of events which may be supposed to have occurred after the nebular stage of evolution. At the various centres of condensation, which now form the sun, planets, and satellites, the swarm of meteorites must bo supposed to have become denser, and the collisions too frequent to allow the gases to condense again, so that by degrees all solid matter in the neigh- bourhood of such centres would be volatilised. Away from these con- densations there were still many free meteorites, but the majority of those which formed the swarm in primitive times would have been absorbed, and the absorption would still go on gradually. The collisions amongst the free meteorites became rarer and less violent, and finally, when relative motion was nearly annulled, almost ceased to occur. The residue of the meteoric swarm then consisted of sparse flights of meteorites moving in streams. There is evidence of the existence of such streams at the present day in the zodiacal light, in falling stars, and in comets. But these are the dregs and sawdust of the solar system, and merely give a memento of the myriads which must have existed in early times, before the sun and planets were formed. The subject of this lecture is a large one, and the limits of time rendered it impossible to do more than speak of the more prominent features of the problem. The value of the investigation of which some account has been given, will appear very different to different minds. To some it will stand condemned as altogether too specula- tive ; others may think that it is better to risk error on the chance of winning truth. It was, however, contended by the lecturer that the line of thought flowed in the channel of truth, and that by its aid many other interesting problems might perhaps be solved with suffi- cient completeness to throw further light on the evolution of nebulas and of planetary systems. [G. H. D.] 384: Professor W. C. Mcintosh [Feb. 1, WEEKLY EVENING MEETING, Friday, February 1, 1889. John Rae, M.D. LL.D. F.R.S. Vice-President, in tlie Chair. Professor W. C. McIntosh, M.D. LL.D. F.R.S. &c. The Life-history of a Marine Food-fish. It is but a few years since the life-history of our most important marine food-fishes was involved in considerable obscurity — not only as regards popular views, but even in resj)ect to the knowledge of men of science. Thus, for instance, in the years 1883 and 1884 the almost unanimous opinion of British fishermen was that our common food-fishes sought the shallow water of the bays and inshore ground generally for the purj)ose of depositing their eggs on the bottom. No observations specially bearing on this point had been made by British zoologists, and a series hud to be undertaken for a public inquiry then in progress — with a result which demonstrated how extensive the reverse of the popular notion was. Again certain comparatively recent authors on British fishes speak of a common fish like the gurnard as spawning twice a year, whereas, after careful observation, no evidence in support of this view has been obtained. The same obscurity veiled the larval and post-larval conditions of most of the food-fishes, even G. O. Sars — in regard to the latter stage — describing no intermediate forms between the larva of 6 mm. and the post-larval stage of 24 mm. in the cod — almost the only fish to which some attention had been paid. On the other hand, our knowledge of the development and life- history of the fresh-water fishes — such as the salmon, trout, and charr — has for many years been well understood — thanks to the labouts of Louis Agassiz and Vogt in Switzerland, Coste and Lereboullet in France, Ransom in England, and Shaw in Scotland, on the scientific side, and of the noblemen and gentlemen of Perth- shire (ably seconded by Robert Buist) in connection with Stormont- field Ponds on the Tay, on the popular side. Much information has also been recently obtained by Dr. Day and Sir J. Gibson Maitland at the excellent ponds of the latter at Howieton. A short time ago, relying on experience derived from fresh- water fishes, not a few imagined the eggs of marine fishes as readily visible and tangible objects — possibly associated in their minds with certain practices in trout-fishing, or it may be with the manufacture of caviare. Recent investigations, however, have shown that in most 1889.] on the Life-Mstorij of a 3Iarme Food-Jish. 385 marine food-fishes the eggs are minute glassy spheres which float freely in the ocean. For a knowledge of this fact we are indebted in the first instance to Prof. G. 0. Sars, of Christiania, a naturalist trained from boyhood under a distinguished father, and who by a fortunate appointment to a fishery post in Norway, was enabled to discover that the eggs of the cod, haddock, and gurnard, floated in the water, or, as we term it, were pelagic. He thus oj)ened up a new field in the economy of the food-fisbes, which in a great maritime country like ours ought not to have remained so long unexplored. Lately, however, attention has been earnestly directed to the subject, and the labours of Cunningham, Brook, Prince, and others have made considerable advances in this department. It is now known that the great majority of our British marine food-fishes — indeed all our most valuable kinds (including even the sprat and the pilchard amongst the clupeoids) produce minute eggs (Fig. 1) — as transparent as crystal, and which float freely throughout the water. Fig. 1.* These eggs, moreover, are not all shed at once, as in the case of the salmon, but suc- cessive portions of the ovary become ripe, and the eggs then issue externally. If by uny accident or irregularity — as for instance the confinement of a flounder in an unhealthy tank — this gradational issue is interfered with, the animal dies from the great dis- tention caused by the pent-up eggs. In the case of the cod this gradual issue of the eggs continues probably for a week or two, Pelagic egg of the Ling, so that the progeny of a single fish in one enlarged, season may vary considerably in size. From the early months of the year onward to late autumn the sea off our shores thus abounds with pelagic eggs, those of the rockling, haddock, and sprat being amongst the earlier forms, while the later include those of the sole. As indicated in the Trawling Report, and now supported by further experience, it would be a very difficult matter indeed to arrange for a close time in the sea, that is to say, for a limited period during which the mature fishes might be permitted to spawn in peace. This, however, in the case of individual species, such as the cod, might more readily be carried out, so as to save the mature fishes at the spawning period. In a vessel of still sea water these transparent glassy spheres rise at once on issuing from the fish, and form a stratum on the surface. Even the ripe portions of ovaries removed from the rejected viscera on a j)ier will show the same features, and thus, indeed, they first came before the lamented Lord Dalhousie at * I am indebted to Mr. E. E. Prince, B.A. for kindly aiding me with sketches for the woodcuts. The sketch of Motella is by Dr. Scharff. When floating freely in the sea the blastodisk is inferior. 386 Professor W. C. Mcintosh [Feb. 1, Anstrutlier. In the sea, however, they are seldom met with on the surface, and the tow-nets require to be snnk a fathom or two to capture them, for their specific gravity is so little less than that of sea water that they are carried hither and thither by the currents in everv direction. Some indeed are captured near the bottom by nets attached to the trawl-beam, while experience with the large net of the St. Andrews Laboratory has proved that a great number are carried in mid water. When these glassy eggs issue from the female fish they are soon fertilised in the surrounding water : so that in British seas at any rate non-fertiKsation is one of the rarest conditions in pelagic ecrcrs. It is indeed more likely to happen in the case of the herring, which deposits its eggs in masses on the bottom, or in artificial circumstances in tanks. The unfertilised egg soon becomes opaque and sinks, so that it is readily recognised. In this connection I would again refer to the notion not long ago firmly rooted in the minds of many — especially those practically engaged in fishing — that the fishes at the spawning season seek the shallow water in which to deposit their eggs. Now there is little in nature to support this idea. Shore-fishes it is true, such as the lump-sucker and sea-scorpion (Cottus scorpius), do deposit their eggs there (and there cannot be a doubt that some of the masses of eggs thus deposited have been mistaken for those of the f(X)d-fishes), but the edible fishes proper, such as the cod, haddock, whiting, flounders, and others, appear to produce their eggs just where they happen to be feeding at the season. Their eggs are taken in charge by the ocean generally, and hence are independent of any imaginary protec- tion or privilege pertaining to the shallow waters. Moreover, it does not follow that the fishes of an enclosed bay * will increase of themselves. As in the case of the plaice, in shallow sandy bays, it may happen that most of the large mature fishes are beyond the limits, the half-grown or immature forms mainly occur- ring within : pelagic ova therefore must be borne inward, and still more the pelagic young, while the post-larval stages likewise migrate sborewards ; a counter-migration of the older forms subsequently taking place to the deeper water. Such biys therefore, have to depend for their stock of fishes on the unprotected off'shore. If by any chance the latter waters were depopulated the inshore would seriously sufier.t The minute size of the eggs of all the important marine food- fishes enables a fish like the codL for instance, to produce an enormous number— probably about 9,000,000 as against the 18-25.000 of the salmon, or the 10^30,000 of the herring, both of which fishes deposit * For example, closed bv a Fi=h.ery Order. T This ffetare was x>ointed out in the ' Report of H,M. Trawling CommisiioD, nnder Lord Dalhousie.' 1889.] on the Llfe-ld story of a Marine Food-nsTi. 387 their eggs on the bottom. In the same way the very small eggs of the flab proYide for a large annual increase of the species. The translucent eggs, which, unless they contain a globule of oil, as in Fig. 1, are difficult to see in some instances even in a glass vessel, thus escape (by floating throughout the water) the vicissitudes to which a purely surface-life would expose them, such as the admixture of the surface-water with rain, and the attacks of gulls, ducks, and other forms ; and they also are less at the mercy of the active predatory races living on the bottom, not to allude to the risks of being swept by storms on the beach or captured and de- stroyed by the ground-rope of the trawler. Nature indeed could have devised no method more secure than this for the safe increase of those valuable fishes which for ages have peopled our waters, and, with Prof. Huxley, I venture to say, will perhaps people them for ages yet to come, notwithstanding the persistent efforts of man to annihilate them. Some good observers, for example, Prof. Piyder in America, have attached much importance to the oil-globule in eggs which are pelagic ; but its buoyant influence has been slightly over-estimated, for, as he himself shows, some contain no oil-globule, while the massive oil-globnles in the eggs of the salmon and cat-fish have no such eflect.* They float, as well shown by lEi*. Edward E. Prince,! solely in virtue of their specific gravity, which is somewhat less than that of sea-water. The moment fresh water is added they sink, as they likewise often do when transferred from a vessel filled at sea into one containing shore- water. AYhile immediately after deposition these minute spheres are prone to accident from impurity and sudden changes in the tempera- ture of the water, such would not seem to be the case after develop- ment has made some progress. Thus many living eggs will be found in odoriferous vessels brought from sea by the fishermen if the enclosed embrycs have re^iched an advanced stage. Again, while carrying out some experiments on temperature (at the suggestion of Prof. Huxley^ during the Trawling Expeditions, I had occasion to heat a test-tube containing some of the eggs of the flounder, so as to make them rush up and down the vessel most actively. Considerable heat was applied, and under the impression the eggs were irretrievably * Prof. Eyder classifies buoyaut ova into (1) those in wliicli the specific gravity of the yolk is diniinislied, ex. cod ; (2) those in which large oil-drops in an eccentric position aid in causing the eggs to float ; and (3) those in which a very large oil-drop caused the ovum to float even in fresh water. Mr. Prince has shown that tl,e number of buoyant eggs without oil is at least equal to the number with oil-drops. The statement of the former, therefore, that the cod's egg is unique in floating by the diminished specific gravity of the protoplasmic matter of the vitellus does not traverse the view of the latter. Moreover, it mnst be remembered that the oil-globnle in many is not permanently eccentric, but moves throughout the yolk. t Secretary to the Mussel and Bait Committee. 388 Professor W. C. Mcintosh [Feb. 1, injured, the tube was set aside. Some days afterwards, wbeu ex- plaining the nature of the experiment to Prof. Ewart, be noticed motion in tbe tube, and further examination showed that after all this exposure to heat the little flounders had emerged as usual, and were alternately floating and swimming about in the water. On the other hand, severe frosts are fatal to ova crowded in shallow vessels, in many cases actual rupture taking place ; * and the same occurs in large eggs, for example those of the catfish, deposited on the bottom of the vessel. Out of the little glassy sphere, after a longer or shorter interval (varying from a few days to a few weeks, according to temperature), comes a minute and nearly transparent fish (Fig. 2) which at first is often as passive in the currents as the eggs themselves. f It soon, how- ever, uses its tail for swimming and its pectoral fins for balancing. Its shape is somewhat like that of a tadpole, partly from the large head, but mainly from the great size of the yolk-sac, which contains a store of nourishment on which the little mouthless creature, about Fig. 2. Larval Ling, immediately after hatching. 3 mm. long, sustains itself for a week or ten days. In this respect it somewhat resembles the young salmon in which a much larger collection of the same food supports it about six weeks amongst the gravel in the spawning-bed of the river, though a closer scrutiny reveals certain essential differences. Thus the store of nourishment in the yolk-sac of the salmon is taken up by the bloud-vessels which branch in a complex manner over the whole yolk, whereas in the young cod, though tlie heart is present and pulsating, not a blood- vessel at first is seen, and none ever enters the yolk-sac. The absorption of this nourishment therefore must take place by aid of the cells and tissues themselves, and there is nothing specially wonderful in this, when the conditions in the endoderm of Hydra, and other instances of intracellular digestion are considered. It has been mentioned that these minute and most delicate little * ' Nature,' June, 1886. t For some years tlie development of fishes has been studied by able workers, amongst others on the Continent, by Gotte, Kupflfer, Hoffman, Henneguy, E. Van Beueden, 0^jannikov, and Rafaele; in America, by Alex. Agassiz, Kyder, and Whitman ; while in our own country, Ransom, Klein, Cunningham, Prince, and Brook have carried out similar researches. 1889." on the Life-history of a Marine Food-fish. 389 fishes are nearly transparent, and this is more or less the case throughout, though in the majority — even before they leave the egg — points of pigment appear here and there in the skin, so as to give them a distinc- Fig. 3. Live character (Fig. 3). After hatching, these pigment-spots branch out in a stellate manner, thus becoming more evident, and it is found that in most cases each little food-fish has colours of its own. Thus the cod (Fig. 4) is known by its four somewhat regular black bands, the pigment on the haddock being less defined, the whiting by its canary-yellowish hue, the gurnard by its chrome-j'ellow, the ling by its gamboge-yellow, the flounder by its yellow and black, and so on. All these hues, however, become greatly modified during subsequent develoj)ment, indeed the pigment in no group of vertebrates shows more remarkable changes between the young and adult states than certain of our food-fishes. Thus for instance the cod is characteristically speckled in its tiny youth Flounder, showing pigment in the &Q,g, Fig. 4. Fig. 5. A ^^^ /n^ K Larval Cod with black spots or bands, slightly enlarged. Aggregation of pigment in Post-larval Cod. (Fig. 4), next it becomes more or less uniformly tinted, then the pigment groups itself somewhat irregularly on the sides (Fig. 5); thereafter it is boldly tesselated (Fig. 6), subsequently blotched Fig. 6. Tesselated condition of young Cod (spirit-preparatiun). with reddish brown, and finally in its adult condition it again puts on more or less uniform tints. The ling shows a similar series 390 Professor W. C. Mcintosh [Feb. 1, of transformations, the colours, however, differing in their arrange- ment, being marked with gamboge-yellow in its larval, slightly barred in its early post-larval stage, then the body becomes more or less uniformly tinted in its post-larval phase, and the little fish is furnished with a pair of enormously develojDed and bright yellow ventral fins (Fig. 7) — so different from the short ones of the adult. Fig. 7. Long-finned Post-larval Ling, enlarged. It is next striped longitudinally when about three inches long (Fig. 8), thus affording a great contrast to the tesselated condition of the young cod. In this stage an olive -brown band passes from the tip of the snout in a line with the middle of tLe eye, straight backward to the base of the caudal fin-rays. The pale ventral surface bounds it inferiorly, while a dorsal stripe with a beautiful opaline lustre runs from the tip of the snout, over the upper part of each eye to the tail, on ^^hich it is opaque white, thus giving the Fig. 8. Young Ling, about 3 inches long (in s])irit). fish a characteristic appearance. The dorsal line from the brain backward is distinguished by a narrow edge of dull orange or pale olive, which relieves the colours formerly mentioned, and the general effect is varied by two black specks in the dorsals. "When it is double the length (i. e. 6 or 7 inches) a complete change has taken place in its coloration (Fig. 9). Instead of beiug striped the fish is now boldly and irregularly blotched — both dorsally and laterally, the region of the white stripe being indicated by the pale and somewhat scalloped area dividing the dorsal from the lateral blotches. Fourteen or fifteen bro',vnish blotches occur between the pectorals and the base of the tail, and they arc separated by the 1889/ on the Life-Jiistory of a Marine Food-fish. 391 whitish areas, which thus assume a reticulated appearance, and both kinds of pigment invade the dorsal fins. Other touches of dark Fig. 9 ' WS 'M "w 'i'^^n ^^- ~^fe^~J^ ::^;.^^%V^-.X^ >.\^^. NXNXXX-^. ^.^ ■ Young Ling in the barred stage. About half natural size. Fig. 10. pigment on the fins and tail increase the complexity of the colora- tion at this stage. Again, some species, like the gurnard, have pigment over the yolk-sac before they are hatched, others have not. The dragonet in its post-larval (and pelagic) stage has its ventral surface deeply tinted with black pigment, while in the adult, a ground-loving fish, it is white. The St. Andrew's cross in the eye of the post-larval four-horned Cottus (0. quadricornis) is another remarkable feature (Fig. 10). No more interesting or more novel field, indeed, than this exists in the whole range of zoology ; but the investigations need ships and boats, with expensive appliances, as well as persevering work for several seasons. We have only been able to open the field at St. Andrews by the help of the Trawling Commission under Lord Dalhousie, and subsequently by the aid of the Fishery Board. It may be asked, Why is all this remarkable varia- tion in colour? Just for the same reason that the young tapirs and wild pigs are striped, or the young red deer spotted — the adults in each case being uniformly tinted. Such features indicate their genetic relation with ancestral forms having these marks ; and, more- over, in the struggle for existence, such variations in tint conduce to the safety of the young. The view of Eimer that the markings in animals are primi- tively longitudinal would not suit for many fishes, notably for the young cod, ling, and Pleuronectids, and, indeed, Haacke has already pointed this out from a study of the Australian fish, Helotes scotus* the adult of which is marked by eight longitudinal bands, while Head of Cottus quadricorni with St. Andrew's cross in eyes. One of the Pristipomatidae. 392 Professor W. C. Mcintosh [Feb. 1, Fig. 11, young specimens present in addition a row of clear transverse bands which subsequently disappear. The larval salmon enters the world of a size — though small — that is readily recognisable, viz. about three-fourths of an inch in length, but the marine forms under consideration, from their minute size and glassy translucency, are almost invisible to the naked eye — just a gleam of light broken by the passage of a different medium, or a tinge of pigment, arresting attention. Only in the cat-fish (which is not much — though it ought to be more — of a food-fish) with its large egg, have we a size nearly reaching that of the salmon at birth. We had left the larval fish tossed about by the currents and unable to struggle against them, now floating with its yolk-sac uppermost, or hanging in the water with its head downward, and again making spasmodic darts hither and thither. Soon, however, it gathers strength, and at the end of a week or ten days it glides actively through the water, and avoids both obstacles and enemies, the young cod nimbly escaping the forceps, poising itself in the water with its large pectoral fins (Fig. 11), and evincing both intelli- gence and dexterity. Moreover, this activity greatly promotes respiration in those like the gurnard with a motionless mandible, the water being thus sent through the mouth and over the bran- chial region. Its mouth has now opened and the yolk-sac has been absorbed, while it feeds on the most minute of the little Copepods, especially those almost microscopic in size, that swarm in the surrounding water. The provision whereby such little fishes find in the ocean food suited to their capacities is one of the most striking features in nature, but it has only recently been carefully investigated.* It is a notion no longer tenable that during the winter and spring the sea — to a large extent — is devoid of the wealth of pelagic life so characteristic of the summer months — ^just as it is of the genial waters of the tropics. For several years, however, it has been known that a vast abtindance of minute life of all kinds is present throughout the entire year — and from the surface to the bottom. Moreover, during the warmer months a constant succession of young forms Anterior (ventral) region of larval Cod with great pectoral fins, magnified. * Vide La fanne pelag'que du Golfe de Marseille, par Gourret, Ann. du Mnsee d'M=t. nat. de Marseille, II. 18S4. The pelagic fauna of our shores in relation to the nourishment of the young food-fishes, Ann. Nut. Hist. Feb. 1887. ALo Hensen and Mobius in tiinfter Bericht der Kommission zur wiss. &c. der deutschen Meere. Berlin 1887, pp. 1 and 109. 1889.] on the Life-Mstory of a Marine Food-jisJi. 393 rises from the eggs both of the sedentary and creeping animals on the bottom to the surface — where they sport in the summer sun, undergo certain changes, and again descend as they assume the form of the adult. The pelagic young food-fishes — swimming freely in the ocean — thus have a double chance at them — first in their very early stage as they rise, and again in their larger and later condition as they descend. The enormous numbers, countless variety, and ever-changing nature of the small animals either directly or indirectly constituting the food of these little fishes form an im- portant feature in the economy of the sea. Such animal forms comprise those long known in the British seas, besides others more familiar to arctic voyagers, or to the sunny waters of the Medi- terranean, for, with modern apparatus and persistent eiibrt (thanks to the- enlightened views of the Government acting through the Fishery Board), our knowledge is always extending. It is a remarkable fact that it is primarily to plants in inshore waters that the abundance and variety of animals are in many respects due, especially if estuaries also debouch in the neighbourhood. Thus nowhere are the swarms of Sagittae, Appendicularians, Crustaceans, and other forms of fish-food more conspicuous than in the midst of a sea teeming with diatoms, Ehizosoleniee, and other algoid structures.* These nourish many of the lower forms upon which the crustaceans and other higher types feed, the latter asain falling a prey to the fishes. Moreover, while the larger forms of the Copepods and other crustaceans, for example, afiord suitable nourishment for the more advanced post- larval fishes, the multitudes of larval crustaceans (XaupJii) are adapted to the needs of the smallest larval food-fishes. Xuw this plant-life is specially abundant in A^^ril and May, just when the larval and very young post-larval fishes appear more abundantly in the inshore waters, so that the cycle is nearly complete, viz. from the inorganic medium — through microscopic plant and larval crustacean — to the post-larval fish. I have mentioned the neighbourhood of an estuary as a prolific source of food for young fishes, and I need only explain fui'ther by instancing the case of mussel-beds, which for months pour countless myriads of larval mussels into the adjoining sea, far beyond the needs of the area as regards mussel-culture, and which form a favourite food of the little fishes at all stages, but especially from an inch and a half to three inches in length. These fishes feed on the young mussels as they settle down on the sea-weeds, rocks, and zoophytes in August, after a free-swimming larval existence. Like some of the forms indicated above, mussels live to a considerable extent on microscopic plants and various minute organisms contained in the mud of the estuaries and other sites, so that a rich and favourite food, universally liked by fishes, is the product of these uninviting flats. Moreover, in passing, it may be remarked that, while everywhere preyed on by the food-fishes, it The fact that certain fishes feed on Infusoria has not been overlooked. 394 Professor W. C. Mcintosh [Feb. 1, occasionally happens that in turn the mussel proves a source of incon- venience to them, for, settling on the gill-arches of haddocks, the mussels flourish on a site so suitable for aeration and food that they by-and-by press out the gill-cover and impede respiration, just as the shore-crab (which is also fond of mussels) has its eye-stalks wrenched out by the slow but sure grow^th of the young mussels which have fixed themselves in their sockets. Nemesis thus, by a chance of anchorage, converts a favourite food into a permanent inconvenience. Again, in connection with the pelagic food of fishes, it is a well- known fact that adult cod are extremely fond of sea-anemones,* and some of the rarest species may be procured in their stomachs, a feature by no means snrj)rising when we remember that Abbe Dicquemare cooked and ate his sea-anemones with great relish, and wrote in their favour, as also did Mr. Gosse in our own country. Now, the pelagic young fishes, instead of roaming near the bottom in proximity to the anemones fixed on the rocks, and running the risk of being themselves captured for food, find in the inshore waters in summer the larval PeacJiise in great numbers conveniently attached by the mouth to the little hydromedusa3 {Thaumantias hemisphserica, and T. melanojys) which occur in swarms in mid-water. Moreover, the somewhat larger young food-fishes (2-3 inches) show the same liking for the coelenterate group, by browsing on the zoophytes [Ohelia genicidata) which cover the stones and rocks with feathery tufts, yet the zoophytes are not much the worse for this treatment, for they by-and-by shoot afresh, and clothe the area once more with a minute forest. The rapidity with which such zoophytes grow is remarkable, though we must remember that in some cases the old stock naturally dies ofi" after having produced swarms of pelagic young. Under this rich food, the young fishes grow apace — head and eyes, mouth and accessory organs, body and fins — all rapidly increase, and the little fish, hatched in the spring, say from March to May, is soon in what is known as the post-larval stage, that is, has lost its yolk-sac, has assumed a more or less uniform tint, and has gill-fringes and teeth. It is about a quarter of an inch long, and is both active and intelligent, the large head and large eyes of the young food-fishes being at this stage specially conspicuous, and in marked contrast with such as Coitus. The marginal fin is quite continuous at a quarter of an inch, and the lancet-like termination of the caudal end of the body is noteworthy. About this time the ventral fins of the pelagic fishes first make their appearance, for hitherto they have managed to do without them. Moreover, these fins in some, such as the rockling and ling, undergo remarkable development, forming in the latter (Fig. 7) a pair of great ventral wings consj)iciiously coloured yellow ; yet in the adult (a * A favourite bait for cod in some parts (e. g. Aberdeen and St. Andrews), and from the fact, amongst others, that star-fishes do not molest them on the books, no bait is more successful. 1889.] on the Life-history of a Marine Food-Jish. 395 ground-fish) tliey attain no greater dimensions than in the cod, both having at a certain stage soft, free filaments or tactile processes at the tip. The ventral fins in the post-larval rockling are equally large, the distal half being black, so that at first sight the little fish when captured seems to possess a great ventral spine on each side (Fig. 12). Fig. 12. Post-larval Rockling, enlarged. In the post-larval gurnard, again, the huge pectoral fins form a drapery for the entire body when folded back, only the tip of the tail extending beyond them (Fig. 13). They are indeed proportion- ally as large as in the southern flying gurnards, but in these the fins reach full develojDment only in adult life, while in the young stages they are comparatively small — exactly the reverse happening in the grey gurnard of our seas. The presence of the broad arches of Fig. 13.- Post-larval Gurnard, enlarged. pigment on the pectorals of several forms, such as the present species, green cod, and armed bullhead, is also an interesting feature. We have not yet read the riddle of all these changes, but in the ling the great ventral fins are probably connected with its roaming or pelagic life, and this explanation would also suit in the case of the rockling, both in their mature state seeking their food on the ground. The little fishes at this stage are still more or less translucent, except in the region of the eyes, which are silvery, and on the parts where the pigment occurs. Moreover, their fondness for a minute reddish Copepod (^Calanus finmarcliiciis), which occurs in myriads around them, gives the region of the stomach a faint j)inkish hue from the translucency of the tissues. By-and-by, however, pigment apj)ears, foreshadowing in the cod (Fig. 5) those peculiar squares which give the sides, at a somewhat later stage, their tessellated or tartan-like aspect. Besides, they are found nearer the bottom of the water, so that they can be captured in a naturalist's trawl with a fine gauze bag at the end. There is, therefore, a downward tendency as the little fishes get older Vol. XII. (No. 83.) 2 b 396 Professor W. C. Mclntosli [Feb. 1, Fig. 14. and stronger, and thus in many cases a parallelism exists between tbem and the minute forms on which they prey, for the eggs rise on deposi- tion towards the surface, where the helpless larvae (or newly hatched young fishes) also often occur, and then they seek the lower regions of the water as their size increases. There is much that is wonderful in such a life-history, especially in the metamorphoses or changes of form undergone by many of our best fishes such as the flat fishes (Pleuronectidae), which come out of the egg just like a haddock or cod, with an eye on each side, as in Fig. 2, yet in after life have both eyes on the same side. Nothing like this occurs in any of the higher vertebrates. Gradually during growth the body of the fish increases in depth (Fig. 14), then the right or left eye passes over (Fig. 15) the ridge of the head to the opposite side, while the creature, hitherto pela- gic, sinks deeper in the water and exhibits a tendency to lie on the side from which the eye has passed, and which gradually loses its dark pigment so as to become white.* It finally reaches the bottom, taking uj) its residence amongst the sand or sandy mud, and lying with the two eyes and the coloured side up, the white underneath. The mode by which the eye travels round has been a fruitful source of discussion with scientific men, and Young " Witch " (Pleuronectes cynoglossus) in the third stasje, enlarcred. Fig. 15. Young " Witch " at a later stage, the left eye just appearing on the ridge of the head, enlarged. amongst these the names of Steenstrup, Malm, Schiodte. and Alex. Agassiz abroad, with Wyville Thomson and especially Traquair in our own country, are well known. The fact is — two methods exist in nature ; in the one the eye travels over the ridge of the head, as just * The tardy disappearance of tlie pigment in some forms is interesting. 1889.] on the Life-Mstonj of a Marine Food-fish. 397 described iu the flounder ; in the other it traverses the soft and yielding tissues of the young fish, and so gains the other side. In Plagusia, the species in which the latter remarkable change occurs in the post-larval stage, the general tissues are so transparent that the creature in a glass vessel can only be noticed by the two apparently disembodied eyes, or by the gleam of light caused by its movements ; and before the change ensues in its eyes it can look obliquely through its own body and see what jjasses on the other side.* Up to this stage in the life-history of both round and flat fishes it will have been apparent that the etforts of man can have little efiect on the vast multitudes of the eggs and minute fishes. His trawl sweeps beneath them, or they are carried harmlessly through its meshes. Not even in the case of a trawl blocked by a fish-basket and several large skate are any likely to occur. No example indeed was pro- cured in the trawling expeditions for the Commission under Lord Dalhousie. The hooks of the liners are too large for the mouth at this stage, and hence they escape capture. Their small size and translucency also seem to afford j)rotection in the case of predatory fishes of their own or other kinds, for they are rare, so far as present obser- vation goes, in the stomach of any fish. Their great numbers are doubtless kept in check by some means, and we know that even jelly-fishes (e. g. PleurohracMse) are very fond of post-larval fishes. It is only when they become somewhaf larger that they are preyed on by their own and other species, and are swept up in thousands by the destructive shrimp-nets on our sandy shores. While the little food-fishes are assuming the change of hue indicated in the preceding pages, they in many cases seek the inshore waters ; at least systematic use of the mid- water and other nets prove that at certain seasons they are met with in large numbers at the entrance to bays or off shore, and that a little later — in the case of the cod from the first of June onwards — they are visible from the rocky margins. The coloration in this species (cod) is now beautifully tessellated (Fig. 6), and they swim in groups, often in company with the young green cod, at the margin of the rocks at low water, and in the little tidal bays connected with rock-pools. The latter are often richly clothed with tangles, bladder-weed, red and green seaweeds, and the green Ulva — amidst the mazes of which the young fishes find both food and shelter, capturing the little crustaceans (Copepods, Ostracods, and others) swimming there, and snatching the young mussels and minute univalve mollusks from the blades of the sea- weeds. To the zoologist few sights are more interesting than to watch the little cod in these fairy lakes, as they swim in shoals against the current, balancing themselves gracefully in the various eddies by aid of their pectoral fins. In a mixed company, the young cod are easily recognised by their coloration, and the reddish hue of * Alex. Agassiz, ' Proceed. Americ. Acad. Arts, and Sc, vol. xiv. p. 8, 1878. 2 E 2 398 . Professor W. C. McTntosli [Feb. 1, fclie occiput, for tlie blood-vessels there sliine tlirough tlie tissues, whicli generally are more translucent than in the green cod. Prof. G. 0. Sars considered that about this stage there was an intimate connection between them and the hordes of medusae (^Aurelia and Cyaned) which abound in the inshore waters towards the end of summer. He thought the young cod aj^proached the medusa for the sake of the minute pelagic animals stupefied by its poisonous threads, and that the fish repaid this favour by picking off a parasitic crustacean {Hyyeria medusaruiii) vfhich. clings to the medusa. Observations, con- tinued for a long period in this country, however, show that this connection is only casual and of very little im^Dortance, and that certain Hyperise are occasionally found in vast numbers in a free condition. As the season advances, the young cod are joined off the rocky ledges by a few pollack and whiting, but not by the haddock, which appears to have certain social views of its own — keeping probably a little farther out. The size of these cod late in autumn, as in October, varies, some reaching 4 to 5 inches in length. Their food ranges from zoophytes to crustaceans, mollusks, and small fishes, and in confinement the larger are voracious, an example about 5 inches readily attacking a smaller (3 inches) and swallowing it as far as possible, though for some time a considerable portion of the body and tail of the prey projected from the mouth. Moreover, the tessellated condition becomes less marked, and as they approach 8 inches in length a tendency in some to uniformity of tint is noticeable. Many of those, however, that continue to haunt the rocky shores and the tangle-forests beyond low water still retain for some time mottled sides, and they are known by the name of rock- cod. Further, while their growth in the earlier stages is less marked, it is now^ very rapid — even in confinement. The exact rate of growth in the free condition in the sea is difficult to estimate, but the little cod of an inch and a half to an inch and three-quarters in June reach lengths varying from 3 to 5 inches in autumn, and in the tanks of the laboratory, specimens 5 inches in August attain 8 inches the following March. At Arendal, in Norway, where o23portunities for watching the growth of cod in confinement have been supplied with a liberality yet foreign to our country, Dannevig found that the cod of 3 mm. in April reached only 15 mm. in June, a length somewhat at variance with the condition, as above stated, on our shores. In July they measured 2 inches, in September 3 inches and a half, and in October about 4 J inches. The second year they attained 14 to 16 inches in length. In artificial circumstances, as well as in nature, it is found that great variation exists in the sizes of the young fishes of the same age, and this variation would not seem to be related to temperature. At the stao'es just mentioned they now come under the notice of both liner and trawler, for young cod 5 or 6 inches in length occasionally take a haddock-hook, and those somewhat larger (9 to 18 inches) occur in certain hauls of the trawl, especially off a 1889.] on the Life-Mstory of a Marine Food-fisli, 399 rocky coast like that of Aberdeenshire, south of Girdleness, as well as on the hooks of the liners on rough ground. Sj)ecial trips, indeed were, and perhaps are, made by the liners for the capture of these young cod (termed codling), and thus their numbers are kept in check. So far as present observations go, therefore, the young cod in a free condition reach the length of from 4 to 10 inches the first year, while in the second they attain from 10 to 20 inches or more. It probably takes 3 or 4 years (and this is the original opinion of Sars) or more to reach full maturity and a length of 3 feet or upwards ; though he mentions having seen young cod a foot in length, with mature roe and milt, in the fish-market of Christiania. These, how- ever, were probably abnormal examples. Let us now glance at the condition in the whiting. Its earlier post-larval stages immediately following those observed in the tanks at the laboratory (for we failed to rear them) are even now somewhat obscure, but they probably approach those of allied forms, such as the cod and haddock. The characteristic nature of the larval pigment, however, would lead to the belief that perhaps in the brighter tints (e, g. yellow), differences may occur. Such, however, are lost before they come under observation ; for all these delicate and minute forms are dead before reaching the deck, and indeed considerably altered. The pressure to which they are subjected in the large mid-water net by the crowds of hydromedusas, and ctenophores alone w^ould suffice for this, and the handling of the heavily laden net increases the dangers to forms so fragile. One about 12 mm. shows in spirit the dorsal and anal fins outlined though not separated from each other, and permanent rays occur in them and in the caudal. Minute ventral s are present, while the pectorals form large mobile fans. Groups of black pigment-corpuscles are distributed along the base of the dorsal and anal fins and over the brain, and a similar series occurs along the ventral median line of the abdomen. The sides have these blackish pigment-corpuscles more generally distributed than in the cod. No barbel is noticeable. When a little longer (15 mm.), the species is distinguished from the young cod by a more abundant distribution of black pigment-specks along the sides of the body and on the fins, and by the greater length and diminished depth of the first anal iin. The median line of pigment still runs along the ventral surface of the abdomen. At 20 mm. the characters that distinguish it from the cod of the same size are better marked, viz., the distribu- tion of dense blackish pigment along the base of the dorsal fins ; and it soon spreads downward over the sides. The first anal fin assumes the character of the adult, and a minute papilla indicates a barbel. Between the stage just mentioned and a length of 28 mm. a decided change in the dense dorsal jDigment takes place, viz., a tendency to form separate groups or touches (Fig. 16). These differ from the cod in being confined to the dorsal region, though a few bars occur at the base of the tail. The fish is also now minutely flecked, all over the 400 Professor W. C. Mcintosh. [Feb. 1, head, sides, snout, and fins, witli black pigment, and its general outline approaches that of the adult. It is at once distinguished from the young cod by the shortness of the snout, irrespective of the features Fig. K;. Young Whiting with serrated dorsal pigment-band, and parasitic Chaliinus. already pointed out, by the coloration, and by the shaj^e of the first anal fin. The differentiation of the two species, viz. the cod and the whiting, is very marked in spirit at the length of 34 mm. In the whiting the median dorsal fin is less abruptly elevated than in the cod, and the first anals diverge widely, the elongation of the latter being probably connected with the abbreviation of the abdomen. The body of the whiting is more plump and neatly rounded than in the cod, which is flatter and has generally a more i^rominent abdomen. The l)igment-specks closely cover the sides of the body in the whiting, as well as the membranous w^ebs of the dorsal fins, and are continued on the head. The pigment at the base of the caudal rays is more distinct in the whiting, and the lancet-like caudal termination of the body is longer in this species. The myotomes are coarser in the cod, and the surface has little of the dappled silvery sheen of the whiting. The chromatophores are larger in the cod, and are grouped in blotches over the surface, wdth intermediate pale patches, and the shoulder and head have much less j^ignient than in the whiting. Both the pectoral and ventral fins of the cod are shorter than those of the whiting. The snout in the latter is shorter and broader as well as deeper, and the short snb-mental papilla is in contrast with the long barbel of the cod of the same length. The whiting, produced from an egg of larger size, would appear to attain a plump body and finished outline sooner than the cod. The foregoing stages are very abundant in autumn in the deej) water off the Isle of May and the mouth of the Forth, but they also appear west of Inchkeith in the latter estuary. They are indeed more characteristic of the former region, as far as present observations go, than of the shallow water of the open bays such as St. Andrews, though on reaching a somewhat larger size they are quite common in the latter expanse. Both they and the cod in these ea.rly stages are infested by a crustacean parasite (Chalimiis), which adheres to various parts of the head and body, just as the larval Anceus tenaciously attacks the young flounders in tidal harbours and inshore grounds. 1889.] on the Life-history of a Marine Food-fish. 401 The young v/biting at a later stage (3-5 in.) joins the young cod at the margins of the rocks, and forms independent shoals in tidal harbours, as well as occurs some distance off shore, being frequently got in the mid-water net in the deeper water. Towards the latter size (6-7 in.) it readily takes the hooks of the liner, and in certain bays the multitudes of young whiting prove an inconvenience to the fisher- men. As it increases in size great shoals are formed in the offing, though a few small are almost always found in inshore waters. The young round fishes, such as cod, haddock, and whiting, of similar or nearly similar size, seem respectively to herd together. Thus it happens that in certain hauls of both liners and trawlers the majority agree in size. This is well known to the liners, who in former days specially sought out the young cod as already indicated. The same feature is observed in many other fishes, and probably conduces to their safety. So far as known, the adult fishes of the three kinds specially alluded to in the preceding paragraph (viz., cod, haddock, and whiting) follow no very definite law in regard to migrations, if we except the apparent congregation in certain regions during the spawning season, as pointed out, for instance by Sars, off Lofoten, where they occur in vast numbers from January to March. In our own country, again, the apj^earauce of shoals of haddocks and whiting in certain locali- ties is another example. How far -such multitudes, however, are influenced by the abundance of food is still an open question. In British seas the herring is the main cause of these congregations in the cod and haddock ; the former chiefly pursuing the fishes, the latter their eggs. In the same way, the abundance of Norway lobsters and similar food on the grounds called banks exercise considerable influence on the presence of cod. It has already been pointed out, however, that in their young stages certain migrations do occur. Thus the post-larval cod by-and- by seeks the lamiuarian region, while the older forms for the most part tend to go seaward. The same occurs even in a more pronounced manner with the ling, the adults of which as a rule are found in deep water. The pelagic post-larval ling seeks downwards as it grows, and is seldom found near the shore till it attains the length of six or seven inches, in short, until it is barred with pigment. As it increases in size it migrates seaward. Similar features are noticed in the plaice. As observed in the trawling expeditions of 1884, only large j^laice as a rule are procured in deep water off the east coast, while the sandy bays abound with those ranging from 11 inches downward, and none of the females of which appear to be mature. Multitudes of little plaice haunt the margins of these sandy beaches, but it cannot be said that forms which have the length, for example, of 3 inches, are confined to any particular line drawn across a bay, for small forms (2-4 in.) occur in hauls all over such a bay as that of St. Andrews. Small turbot and halibut in the same way are often found in the shallow bays, while the large adults are inhabitants of the 402 Professor W. C. Mcintosh [Feb. 1, deeper water. Such would not, however, seem to be the case with certain skate, very large adults of which occur in the shallow water of the sandy voes in Shetland. On the other hand the witch {Pleuronectes cynoglossus) keeps to its special areas, both as regards the young and the adult condition, so that the movements of eggs, larval and post-larval forms, are circum- scribed ; and the same would seem to be the case with the topknot ( Zeugojyierus) and sail-fluke {Arnoglossus). The dab [Pleuronectes limcmda), again, is found in all stages both in comparatively deep and in comparatively shallow water. Almost all our valuable food-fishes, therefore, are produced from minute pelagic eggs, the enormous numbers of which provide for a vast increase and wide distribution of the species ; yet it cannot be said that this habit alone provides for their multij)lication when the case of the herring with its demersal eggs, fixed firmly to the bottom, is considered. It has to be borne in mind, however, that the larval herring immediately mounts upward toward the surface as soon as its strength suffices. Many striking changes occur during growth, both in external form and coloration, but it is difficult at present to lay down any general law that would apply to all cases, though those in which certain migrations take place during growth show such changes very prominently. The young round fishes by-and-by roam about the sea in shoals, led hither and thither mainly by the presence of food ; though in the case of the larger and adult forms, safety or freedom from molestation may have some influence. Though so minute on escaj)ing from the egg, their growth is, by-and-by, rapid, and the duration of life in such as the cod is considerable. Abundance of food, more than any special instinct, would appear to be the main cause of their migrations in the adult or semi-adult state, and that food is as varied as their haunts ; in short it embraces every sub- kingdom up to their own, for fishes and their eggs form a large share of their diet. There would be little difficulty in adding to the sea great numbers of larval forms of any species of which eggs can be procured : yet if a few adults can be obtained in such waters at the proper season it is still an open question whether the natural process with its surround- ings would not be more successful. In the foregoing remarks I have but touched on a few of the leading features of the life-history of a food-fish ; for the subject is one of vast extent, and some of the points embraced in it are by no means easily solved. We have only earnestly entered on the study of the subject in this country within the last few years, and much yet remains to be done, even in some of the most common marine fishes. However, the zoological investigator is here stimulated by the fact that all his labours directly bear on the public welfare, for it need hardly be pointed out that a thorough knowledge of the development and life-histories of our food-fishes is the first step to sound legisla- 1889.] on the Life-history of a Marine Food-fish, 403 tion and eflfective administration. The State has in past years spent princely sums on more or less pure science, as in the memorable voyage of the Challenger. There can be no doubt that at the present moment the public interests demand a searching and long- continued inquiry nearer home, viz. the exhaustive investigation of all that pertains to the food-fishes of our shores, since the problems connected therewith affect the prosperity of so large a portion of the population. [W. C. M.] GENERAL MONTHLY MEETING, Monday, February 4, 1889. Sir James Crichton Browne, M.D. LL.D. F.K.S. Vice-President, in the Chair. John Tomlinson Brunner, Esq. M.P. Augustus Stroh, Esq.- Sir Charles Tennant, Bart. John Tennant, Esq. were elected Members of the Royal Institution. The Special Thanks of the Members were returned to Mr. William Anderson for his present of a portrait of Professor Mendeleef. The Special Thanks of the Members were returned for the following Donation to the Fund for the promotion of Experimental Research : Professor Dewar £50 The decease of Sir Frederick Pollock, Bart. Manager and Vice- President, on the 24th December last, was announced. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — The Governor-General of India — Bibliography of Indian Geology. By R. D. Oldham. 8vo. 1888. The Government of Madras — Madras Meridian Circle Observations, 1865-7. 4to. 1888. Academy of Natural Sciences, Philadelphia — Proceedings, 1888, Part 2. 8vo. 1888. 404 General Monthly Meeting. [Feb. 4, American Academy of Arts and Sciences — Memoirs, Vol. XI. Parts 5, 6, Nos. 6, 7. 4to. 1887-8. Proceedings, Vol. XXIII. Part 1. 8vo. 1888. American FhilosopMcal Society — Transactions, Vol. XVI. Part 2, 4to. 1888. Asiatic Society, Boyal- Journal, Vol. XIX. Nos. 2, 3. 8vo. 1887-8. Asiatic Society, Royal {China Branch) — Journal, Vol. XXII. No. 6. 8vo. 1888. Astronomical Society, Royal — Monthly Notices, Vol. XLIX. Nos. 1, 2. 8vo. 1888. Bankers, Institute o/— Journal, Vol. IX. Part 10; Vol. X. Part 1. 8vo. 1888-9. Bavarian Academy of Sciences — Abhandlungen, Band XVI. Abtheilung 2. 4to. 1887. Sitzungsberichte, 1887, Heft 3; 1888, Heft 1, 2. 8vo. 1888. Bodleian Library — Eeport of the Librarian, 1882-7. 4to. 1888. British Architects, Royal Institute o/— Proceedings, 1888-9, Nos. 5, 6, 7. 4to. Cambridge Pldlosophical Society — Proceedings, Vol. VI. Part 4. 8vo. 1888. Chemical Society — Journal for Dec. 1888 and Jan. 1889. 8vo. Chief Signal Officer, U.S. Army—Annusl Report for 1887, Part 2. 8vo. 1887. Clinical Society — Transactions, Sup. to Vol. XXI. Eeport on Myxoederaa. 8vo. 1888 Crisp, Fran?., Esq. LL.B. F.L.S. &c. M.R.I, {the Editor)— Jommd of the Royal Microscopical Society, 188S, Part 6. 8vo. Dax : Socie't€ de Borda — Bulletin, Treizieme Ann ee, 4« Tremestre. 8vo. 1888. Editors — American Journal of Science for Dec. 1888 and Jan. 1889. 8vo. Analyst for Dec. 1888 and Jan. 1889. 8vo. Athenteum for Dec. 1888 and Jan. 1889. 4to. - Chemical News for Dec. 1888 and Jan. 1889. 4to. Chemist and Druggist for Dec. 1888 and Jan. 1889. 8vu. Electrical Engineer for Dec. 1SS8 and Jan. 1889. fol. Engineer for Dec. 1888 and Jan. 1889. fol. Engineering for Dec. 1888 and Jan. 1889. fol. Horological Journal from May 1888 to Feb. 1889. 8vo. Industries for Dec. 1888 and Jan. 1889. fol. Iron for Doc. 1888 and Jan. 1889. 4to. Murray's Magazine for Dec. 1888 and Jan. 1889. 8vo. Nature for Dec. 1888 and Jan. 1889. 4to. Photographic News for Dec. 1888 and Jan. 1889. 8vo. Revue Scientifique for Dec. 1888 and Jan. 1889. 4to. Telegraphic Journal for Dec. 1888 and Jan. 1889. 8vo. Zoophilist for Dec. 1888 and Jan. 1889. 4to. Florence, Biblioteca Nazionale Cenirale — BoUetino, Num. 71, 72, 73. 8vo. 1888. Indice e Cataloghi IV. I Codici Palatina, Vol. I. Fasc. 8. 8vo. 1888. Franhlin Institide — Journal, No. 757. 8vo. 1888. Geographical Society. Royal — Proceedings, New Series, Vol. X. No. 12; Vol. XI. No. 1. 8vo. 1888-9. Supplementary Papers, Vol. II. Part 3. 8vo. 1888. Geological Institute, Imperial, Vienna — Verhandlungen, 1888, No. 14. 8vo. Jahrbuch, Band XXXVII. Heft 3, 4 : XXXVIII. Heft 3. 8vo. 1888. Hart, Sir Robert, E.C.M.G. — Le Saint Edit; Etude de Litte'rature Chinoise. Par A. T. Piry. 4to. Shanghai, 1879. Holmes-Forbes, A. W. Esq. M.A. M.R.I {the Aidhor)— 'English. History ; William III. to George II. Questions and Answers, 12uio. 1888. Iron and Steel Institute — Journal, 1888, No. II. 8vo. Johns Hopkins University — University Circular, No. 68. 4to. 1888. Studies in Historical and Political Science, Seventh Series, No. 1. Svo. 1889. Kew Observatory — Report, 1888. Svo. Linnean Society — Journal, Nos. 150, 157, 164. Svo. 1888. Manchester Geological Society — Transactions, Vol. XX. Part 1. Svo, 1888. Manchester Steam Users' Association — Boiler Explosions. Board of Trade Reports, 1879-82. fol. 1889.] General Monthly Meeting. 405 Mechanical Engineers Institution — Proceedings, 1888, No. 3. 8vo. Meteorological Society, Eoyal—Qnarterly Journal, No, 68. 8vo. 1888. Meteorological Kecord, Nos. 29, 30. 8vo. 1888. Ministry of Public Works, Rome — Gioinale del Genio Civile, Serie Quinta, Vol. It. Nos. 9, 10, 11. 8vo. And Disegni. fol. 1888. Montpellier Academy of Sciences— "MQnxon an. Tome X. Fasc. 1. 4to. 1881. New York Academy of AS'c2e/ices— Transactions, Vol. Vll. Nos, 3-8. 8vo. 1887-8 Annals, Vol. IV. Nos. 5-8. 8vo. 1888, North of England, Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVII. Part 6. 8vo. 1888. Odontological Society of Great Britain— Transactions, Vol, XXI. No. 2. New Series. 8vo. 1888. Pennsylvania Geological Survey — Annual Report, 1886, Part IV. With Atlas. 8vo. 1887. Atlas, Northern and Eastern Anthracite Field, Part II. AA. 8vo. 1887. Pharmaceutical Society of Great Britain — Journal, Dec, 1888 and Jan. 1889. 8vo. Calendar, 1889. 8vo. Photographic Society— SonxnoA, Vol. XIII. Nos. 2, 3, 8vo. 1888. Rio de Janeiro Observatory — Kevista, Nos. 11, 12. 8vo. 1888. Royal Irish Academy — Transactions, Vol. XXIX. Parts 3, 4. 4to. 1888. Proceedings, 3rd Series, Vol. I. No, 1, 8vo, 1888. Royal Society of London— Proceedings, Nos. 272, 273. 8vo. 1888. Royal Society of New South Wales — Journal and Proceedings, Vol. XXII. Part 1. 8vo. 1888. Sanitary Institute of Great Britain — Transactions, Vol. IX. 8vo. 1888. Saxon Society of Sciences, Royal — Mathematisch-physische Classe : Abhandlung. Band XIV. Nos. 10-13, 8vo, 1888. Philologisch-historischen Classe: Berichte, 1888, Nos. 1, 2. 8vo, 1888. Society of Architects — Proceedings, Vol. I. Nos, "3, 4, 5. 8vo, 1889. Society of Arts — Journal, Dec. 1888 and Jan. 1889. 8vo. Statistical Society — Journal, Vol. LI. I'art 4. 8vo. 1888. St. Petersbourg, Academic Imperiale des Sciences — Memoires, Tome XXXVI. Nos. 6-11. 4to. 1888. Telegrayh Engineers, Society of — Journal, Nos. 75, 76. 8vo. 1888. Vereins r.ur Beforderung des Gewerbfleisses in Preussen — Verhandlungen, 1888 : Heft 9, 10, 4to. Wells, Sir Spencer, Bart. F.R.C.S. M.R.I, {the Author') — Cancer and Cancerous Diseases. (Morton Lecture, 1888.) 8vo. 1889. Wild, Dr. H. {the Director)— AxinaXen der Physikalischen Central-Observatoriums. 1887, Theil IL 4to. 1888. WEEKLY EVENING MEETING, Friday, February 8, 1889. Sm Frederick Bramwell, Bart. D.C.L. F.E.S. Honorary Secretary and Vice-President, in the Cliair. ^ Sir William Thomson, D.C.L. LL.D. F.R.S. M.B.L Electrostatic Measurement. .^e— Hourly Readings, 1886, Part 1. 4to. 1889. Report of the Meteorological Council, RS. 31 March, 1888. 8vo. Weekly Weather Reports, October-December, 1888. 4to. Ministry of Public Works, Rome — Giornale del Genio Civile, Serie Quinta, Vol. II. No. 12. 8vo. And Disegni. fol. 1888. Numismatic Society — Chronicle and Journal, 1888, Part 4. 8vo. 1888. Odontological Society of Great Britain — Transactions, Vol. XXI. Nos. 3, 4. New Series. 8vo. 1888. Pharmaceutical Society of Great Britain — Journal, February, 1889. 8vo. Photographic Society— J omnal. Vol. XIII. No. 4. 8vo. 1889. Richardson, B. W. M.D. F.R.S. M.RI (the Author)— The Asclepiad, Vol. V. No. 21. 8vo. 1889. Rio de Janeiro Observatory — Revista, No, 1. 8vo. 1889. Royal Irish Academy — Transactions, Vol. XXIX. Part 5. 4to. 1888. Ro]jal Society of London — Proceedings, Nos. 274, 275. 8vo. 1889. Philosophical Transactions, Vol. CLXXIX. 4to. 1889. Scottish Society of Arts, i2o?/aZ— Transactions, Vol. XII. Part 2. 8vo. 18.89. Society of Architects— Vxocee^in^s,, Vol. I. No. 7. 8vo. 1889. Society of ylr^s— Journal, February, 1889. 8vo. St. Bartholomew's Hospital— Beporis, Vol. XXIV. 8vo. 1888. Telegraph Engineers, Society of — Journal, No. 77. 8vo. 1889. United Service Institution, Royal — Journal, No. 146. 8vo. 1889. Vereins zur Beforderung des Geiverb eisses in Preussen — Verhandlungen, 1889 : Heft 1. 4to. Victoria Institute— Tv&nssLctions, No. 87. 8vo. 1889. Yorkshire Archxological and Topographical Association— J ourn&l, Part XL. 8vo. 1889. 1889.] Prof. C. Lodge on the Discharge of a Leyden Jar.. 413 WEEKLY EVENING MEETING, Friday, March 8, 1889, Sir James Crichton Browne, M.D. LL.D. F.R.S. Vice-President, in the Chair. Professor Oliver Lodge, LL.D. F.R.S. The Discharge of a Leyden Jar. It is one of the great generalisations established by Faraday, that all electrical charge and discharge is essentially the charge and discharge of a Leyden jar. It is impossible to charge one body alone. When- ever a body is charged positively, some other body is ipso facto charged negatively, and the two equal opposite charges are connected by lines of induction. The charges are, in fact, simply the ends of these lines, and it is as impossible to have one charge without its correlative as it is to have one end of a piece of string without there being somewhere, hidden it may be, split up into strands it may be, but somewhere existent, the other end of that string. This I suppose familiar fact that ail charge is virtually that of a Leyden jar being premised, our subject for this evening is at once seen to be a very wide one, ranging in fact over the whole domain of electricity. For the charge of a Leyden jar includes virtually the domain of electrostatics ; while the discharge of a jar, since it con- stitutes a current, covers the ground of current electricity all except that portion which deals with phenomena peculiar to steady currents. And since a current of electricity necessarily magnetises the space around it, whether it flow in a straight or in a curved path, whether it flow through wire or burst through air, the territory of magnetism is likewise invaded ; and inasmuch as a Leyden jar discharge is oscillatory, and we now know the vibratory motion called light to be really an oscillating electric current, the domain of optics is seriously encroached upon. But though the subject I have chosen would permit this wide range, and though it is highly desirable to keep before our minds the wide-reaching import of the most simple-seeming fact in connection with such a subject, yet to-night I do not intend to avail myself of any such latitude, but to keep as closely and distinctly as jDossible to the Leyden jar in its homely and well-known form, as constructed out of a glass bottle, two sheets of tinfoil, and some stickphast. The act of charging such a jar I have permitted myself now for some time to illustrate by the mechanical analogy of an inextensiblo endless cord able to circulate over pulleys, and threading in some portion of its length a row of tightly-gripping beads which are con- nected to fixed beams by elastic threads. 2 F 2 414 Professor Oliver Lodge [March 8, The cord is to represent electricity ; the beads represent successive strata in the thickness of the glass of the jar, or, if you like, atoms of dielectric or insulating matter. Extra tension in the cord represents negative potential, while a less tension (the nearest analoo^ue to pressure adapted to the circumstances) represents positive Mechanical analogy of a circuit partly dielectric ; for instance, of a charged Cundenser. A is its positive coat, B its negative. potential. Forces applied to move the cord, such as winches or weights, are electromotive forces; a clamp or fixed obstruction represents a rheostat or contact-breaker ; and an excess or defect of cord between two strata of matter represents a positive or a negative charge. The act of charging a jar is now quite easily depicted as shown in the diagram. To discharge the jar one must remove the charging E.M.F. and unclamp the screw, i.e. close the circuit. The stress in the elastic threads will then rapidly drive the cord back, the inertia of the beads will cause it to overshoot the mark, and for an instant the jar will possess an inverse charge. Back again the cord swings, however, and a charge of same sign as at first, but of rather less magnitude, would be found in the jar, if the operation were now suspended. If it be allowed to go on, the oscillations gradually subside, and in a short time everything is quiescent, and the jar is completely discharged. All this occurs in the Leyden jar, and the whole series of oscilla- tions, accompanied by periodic reversal and re-reversal of the charges of the jar, is all accomplished in the incredibly short space of time occupied by a spark. Consider now what the rate of oscillation depends on. Manifestly on the elasticity of the threads and on the inertia of the matter which 1889.] 071 the Discharge of a Leyden Jar. 415 is moved. Take the simplest meclianical analogy, that of the vibration of a loaded spring, like the reeds in a musical box. The stiifer the spring, and the less the load, the faster it vibrates. Give a mathematician these data, and he will calculate for you the time the spring takes to execute one complete vibration, the " period " of its swing. [Loaded lath in vice.] The electrical problem and the electrical solution are precisely the same. That which corresponds to the flexibility of the spring, is in electrical language called static capacity, or, by Mr. Heaviside, permittance. That which corresponds to the inertia of ordinary matter is called electro-magnetic inertia, or self-induction, or, by Mr. Heaviside, inductance. Increase either of these, and the rate of oscillation is diminished. Increasing the static capacity corresponds to lengthening the spring ; increasing the self-induction corresponds to loading it. Now the static capacity is increased simply by using a larger jar, or by combining a number of jars into a battery in the very old established way. Increase in the self-induction is attained by giving the discharge more space to magnetise, or by making it magnetise a given space more strongly. For electro-magnetic inertia is wholly due to the magnetisation of the space surrounding a current, and this space may be increased or its magnetisation intensified as much as we 2)lease. To increase the space we have only to make the discharge take a long circuit instead of a short one. Thus we may send it by a wire all round the room, or by a telegraph wire all round a town, and all the space inside it and some of that outside will be more or less magnetised. More or less, E say, as it is a case of less rather than more. Practically very little effect is felt except close to the conductor, and accordingly the self-induction increases very nearly proportionally to the length of the wire, and not in proportion to the area inclosed : provided also the going and return wires are kept a reasonable distance apart, so as not to encroach upon each other's appreciably magnetised regions. But it is just as effective, and more compact, to intensify the magnetisation of a given sjDace by sending the current hundreds of times round it instead of only once ; and this is done by inserting a coil of wire into the discharge circuit. Yet a third w^ay there is of increasing the magnetisation of a given space, and that is to fill it with some very magnetisable substance such as iron. This, indeed, is a most powerful method under many circumstances, it being possible to increase the magneti- sation and therefore the self-induction or inertia of the current some 5000 times by the use of iron. But in the case of the discharge of a Leyden jar, iron is of no advantage. The current oscillates so quickly that any iron introduced into its circuit, however subdivided into thin wires it may be, is protected from magnetism by inverse currents induced in its outer 416 Professor Oliver Lodge [March 8, skin, as your Professor of Natural Philosophy* has shown, and accordingly it does not get magnetised ; and so far from increasing the inductance of the discharge circuit it positively diminishes it by the reaction effect of these induced currents : it acts, in fact, much as a mass of copper might be expected to do. The conditions determining rate of oscillation being understood we have next to consider what regulates the damping out of the vibrations, i. e. the total duration of the discharge. Resistance is one thing. To check the oscillations of a vibrating spring you apply to it friction, or make it move in a viscous medium, and its vibrations are sj^eedily damped out. The friction may be made so great that oscillations are entirely prevented, the motion being a mere dead-beat return to the position of equilibrium ; or, again, it may be greater still, and the motion may correspond to a mere leak or slow sliding back, taking hours or days for its accomplishment, With very large condensers, such as are used in telegraphy, this kind of discharge is frequent, but in the case of a Leyden jar discharge it is entirely exceptional. It can be caused by including in the circuit a wet string, or a capillary tube full of distilled water, or a slab of wood, or other atrociously bad conductor of that sort ; but the conditions ordinarily associated with the discharge of a Leyden jar, whether it discharge through a long or a short wire, or simply through its tongs, or whether it overflow its edge or puncture its glass, are such as correspond to oscillations, and not to leak. [DiscLarge jar first through wire and next through wood.] When the jar is made to leak through wood or water the discharge is found to be still not steady : it is not oscillatory indeed, but it is intermittent. It occurs in a series of little jerks, as when a thing is made to slide over a resined surface. The reason of this is that the terminals discharge faster than the circuit can supj^ly the electricity, and so the flow is continually stopped and begun again. Such a discharge as this, consisting really of a succession of small sparks, may readily aj^peal to the eye as a single flash, but it lacks the noise and violence of the ordinary discharge ; and any kind of moving mirror will easily analyse it into its constituents and show it to be intermittent. [Shake a mirror, or waggle head, or opera-glass.] It is pretty safe to say, then, that whenever a jar discharge is not oscillatory it is intermittent, and when not intermittent is oscillatory. There is an intermediate case when it is really dead- beat, but it could only be hit upon with special care, while its occur- rence by accident must be rare. So far I have only mentioned resistance or friction as the cause of the dying out of the vibrations ; but there is another cause, and that a most exciting one. The vibrations of a reed are damped partly indeed by friction and * Lord Kayleigh. 1889.] on the Discharge of a Leyden Jar. 417 imperfect elasticity, but partly also by the energy transferred to the surrounding medium and consumed in the production of sound. It is the formation and propagation of sound waves which largely damp out the vibrations of any musical instrument. So it is also in electricity. The oscillatory discharge of a Leyden jar disturbs the medium surrounding it, carves it into waves which travel away from it into space: travel with a velocity of 185,000 miles a second: travel precisely with the velocity of light. [Tuning-fork.] The second cause, then, which damj)S out the oscillations in a discharge circuit is radiation : electrical radiation if you like so to distinguish it, but it differs in no respect from ordinary radiation (or " radiant heat " as it has so often been called in this place) ; it differs in no respect from Light except in the physiological fact that the retinal mechanism, whatever it may be, responds only to waves of a particular, and that a very small, size, while radiation in general may have waves which range from 10,000 miles to a millionth of an inch in length. The seeds of this great discovery of the nature of light were sown in this place : it is all the outcome of Faraday's magneto-electric and electrostatic induction : the development of them into a rich and fall-blown theory was the greatest part of the life-work of Clerk- Maxwell : the harvest of experimental verification is now being reaped by a German. But by no ordinary German. Dr. Hertz, now Pro- fessor in the Polytechnicum of Karlsruhe, is a young investigator of the highest type. Trained in the school of Helmholtz, and endowed with both mathematical knowledge and great experimental skill, he has immortalised himself by a brilliant series of investigations which have cut right into the ripe corn of scientific opinion in these islands, and by the same strokes as have harvested the grain have opened up wide and many branching avenues to other investigators. At one time I had thought of addressing you this evening on the subject of these researches of Hertz, but the experiments are not yet reproducible on a scale suited to a large audience, and I have been so closely occupied with some not wholly dissimilar, but inde- pendently conducted, researches of my own — researches led up to through the unlikely avenue of lightning-conductors — that I have had as yet no time to do more than verify some of them for my own edification. In this work of repetition and verification Prof. Fitzgerald has, as related in a recent number of Nature (February 21, p. 391), probably gone further ; and if I may venture a suggestion to your Honorary Secretary, I feel sure that a discourse on Hertz's researches from Prof. Fitzgerald next year would be not only acceptable to you, but would be highly conducive to the progress of science. I have wandered a little from my Leyden jar, and I must return to it and its oscillations. Let me very briefly run over the history of our knowledge of the oscillatory character of a Leyden jar discharge. It was first clearly realised and distinctly stated by that excellent 418 Professor Oliver Lodge [March 8, experimentalist, Joseph Henry, of Washington, a man not wholly unlike Faraday in his mode of work, though doubtless possessing to a less degree that astonishing insight into intricate and obscure phenomena ; wanting also in Faraday's circumstantial advantages. This great man arrived at a conviction that the Leyden jar dis- charge was oscillatory by studying the singular phenomena attending the magnetisation of steel needles by a Leyden jar discharge, first observed in 18-4 by Savary. Fine needles, when taken out of the magnetising helices, were found to be not always magnetised in the right direction, and the subject is referred to in Germtin books as anomalous magnetisation. It is not the magnetisation which is anomalous, but the currents which have no simple direction ; and we find in a memoir j^ublished by Henry in 1842, the following words : — " This anomaly, which has remained so long unexplained, and which, at first sight, appears at variance with all our theoretical ideas of the connection of electricity and magnetism, was, after considerable study, satisfactorily referred by the author to an action of the dis- charge of the Leyden jar, which had never before been recognised. The discharge, whatever may be its nature, is not correctly repre- sented (employing for simplicity the theory of Franklin) by the single transfer of an imponderable fluid from one side of the jar to the other ; the phenomenon requires us to admit tlie existence of a 'principal discharge in one direction and then several reflex actions hacliword and forward each more feeble than the preceding, until the equilibrium is obtained. All the facts are shown to be in accordance witli this hypothesis, and a ready explanation is afibrded by it of a number of j^benomena, which are to be found in the older works on electricity, but which have until this time remained unexplained."* The italics are Henry's. Now if this were an isolated passage it might be nothing more than a lucky guess. But it is not. The conclusion is one at which he arrives after a laborious repetition and serious study of the facts, and he keejis the idea constantly before him when once grasped, and uses it in all the rest of his researches on the subject. The facts studied by Henry do in my opinion sujiport his conclusion, and if I am right in this it follows that he is the original discoverer of the oscillatory character of a spark, although he does not attemj)t to state his theory. TLat was first done, and comj^letely done, in 1853, by Sir William Thomson ; and the progress of experiment by Feddersen, Helmholtz, Schiller, and others has done nothing but substantiate it. The writings of Henry have been only quite recently collected and published by the Smithsonian Institution of Washington in accessible form, and accordingly they have been far too much ignored. * ' Scientific Writings of Joseph Henry,' vol. i, p. 201. Published hy the Smithsonian Institution, "Washington, 1886. 1889.] 071 the Discharge of a Leijden Jar. 419 The two volumes contain a wealth of beautiful experiments clearly recorded, and well repay perusal. The discovery of the oscillatory character of a Leyden jar dis- charge may seem a small matter but it is not. One has only to recall the fact that the oscillators of Hertz are essentially Leyden jars — one has only to use the phrase " electro-magnetic theory of light " — to have some of the momentous issues of this discovery flash before one. One more extract I must make from that same memoir by Henry,* and it is a most interesting one ; it shows how near he was, or might have been, to obtaining some of the results of Hertz; though if he had obtained them, neither he nor any other experi- mentalist could possibly have divined their real significance. It is, after all, the genius of Maxwell and of a few other gi'eat theoretical j)hysicists whose names are on everyone's lipsl which endows the simple induction experiments of Hertz and others with such stupendous importance. Here is the quotation : — " In extending the researches relative to this j)art of the investi- gations, a remarkable result was obtained in regard to the distance at which induction effects are produced by a very small quantity of electricity ; a single spark from the prime conductor of a machine, of about an inch long, thrown on to the end of a circuit of wire in an upper room, jDroduced an induction sufficiently powerful to magne- tise needles in a parallel circuit of iron placed in the cellar beneath, at a perpendicular distance of 30 feet, with two floors and ceilings, each 14: inches thick, intervening. The author is disposed to adopt the hypothesis of an electrical jAenum [in other words, of an etherj, and from the foregoing experiment it would appear that a single spark is sufficient to disturb perceptibly the electricity of space throughout at least a cube of 400,000 feet of capacity ; and when it is considered that the magnetism of the needle is the result of the difference of two actions, it may be further inferred that the diffusion of motion in this case is almost comparable with that of a spark from a flint and steel in the case of light." Comparable it is, indeed, for we now know it to be the self-same process. One immediate consequence and easy proof of the oscillatory character of a Leyden jar discharge is the occurrence of phenomena of sympathetic resonance. Everyone knows that one tuning-fork can excite another at a * Loc. cit., p. 204:. t And of one whose name is not yet on everybody's lips, but whose profound researches into electro-magnetic waves have penetrated further than anybody yet understands into the depths of the subject, and whose papers have very likely contributed largely to the theoretical inspiration of Hertz — I mean that powerful mathematical physicist, Mr. Oliver Heaviside. 420 Professor Oliver Lodge [March 8, reasonable distance if both are tuned to the same note. Everyone knows, also, that a fork can throw a stretched string attached to it into sympathetic vibration if the two are tuned to unison or to some simple harmonic. Both these facts have their electrical analogue. I have not time to go fully into the matter to-night, but I may just mention the two cases which I have myself specially noticed. A Leyden jar discharge can so excite a similarly-timed neigh- bouring Leyden jar circuit as to cause the latter to burst its dielectric if thin and weak enough. The well-timed impulses accumulate in the neighbouring circuit till they break through a quite perceptible thickness of air. Put the circuits out of unison by varying the capacity or by including a longer wire in one of them ; then, although the added wire be a coil of several turns, well adapted to assist mutual induc- tion as ordinarily understood, the effect will no longer occur, until the capacity is suitably diminished and the synchronism thus restored. That is one case, and it is the electrical analogue of one tuning- fork exciting another. It is too small at present to show here satisfactorily, for I only recently observed it, but it is exhibited in the library at the back. The other case, analogous to the excitation of a stretched string of proper length by a tuning-fork, I published last year under the name of the experiment of the recoil kick, where a Leyden jar circuit sends waves along a wire connected by one end with it, which waves splash off at the far end with an electric brush or long spark. I will show merely one phase of it to-night, and that is the reaction of the impulse accumulated in the wire upon the jar itself, causing it to either overflow or burst. (Sparks of gallon or jDint jar made to overflow by wire round room.*) The early observations by Franklin on the bursting of Leyden jars, and the extraordinary complexity or multiplicity of the fracture that often results, are most interesting. His electric experiments as * During the course of this experiment, tlie gilt paper on tlie wall was observed by tlie audience to be sparkling, every gilt patch over a certain area discharging into the next, after the manner of a spangled jar. It was probably due to some kind of sympathetic resonance. Electricity splashes about in con- ductors iu a surprising way everywhere in the neighbourhood of a discharge. For instance, a telescope in the hand of one of the audience was reported afterwards to be giving off little sparks at every discharge of the jar. Every- thing which happens to have a period of electric oscillation corresponding to some harmonic of the main oscillation of a discharge is liable to behave in this way. When light falls on an opaque surface it turns into some other form of energy. What the audience s:iw was probably the result of waves of electrical radiation being quenched or reflected by the walls of the room, and generating electrical currents in the act. It is these electric surgings which render such severe caution necessary in the erection of lightning-conductors. This explanation is merely tentative. I have had no time to investigate the matter locally. 1889.] on the Discharge of a Leyden Jar. 421 well as Henry's well repay perusal, though, of course, they belong to the infancy of the subject. He notes the striking fact that the bursting of a jar is an extra occurrence, it does not replace the ordinary discharge in the proper place, it accompanies it ; and we now know that it is precipitated by it, that the spark occurring properly between the knobs sets up such violent surgings that the jar is far more violently strained than by the static charge or mere difference of potentials between its coatings ; and if the surgings are at all even roughly properly timed, the jar is bound to either overflow or burst. Hence a jar should always be made without a lid, and with a lip protruding a carefully considered distance above its coatings : not so far as to fail to act as a safety valve, but far enough to prevent overflow under ordinary and easy circumstances. And now we come to what is after all the main subject of my discourse this evening, viz. the optical and audible demonstration of the oscillations occurring in the Leyden jar spark. Such a demon- stration has, so far as I know, never before been attempted, but if nothing goes wToug we shall easily accomplish it. And first I will do it audibly. To this end the oscillations must be brought down from their extraordinary frequency of a million or hundred thousand a second to a rate within the limits of human audition. One does it exactly as in the" case of the spring — one first increases the flexibility and then one loads it. [Spark from battery of jars and varying sound of same.] Using the largest battery of jars at our disposal, I take the spark between these two knobs — not a Lmg spark, i inch will be quite sufficient. Notwithstanding the great capacity, the rate of vibration is still far above the limit of audibility, and nothing but the customary crack is heard. I next add inertia to the circuit by including a great coil of wire, and at once the spark changes character, becoming very shrill but an unmistakable whistle, of a quality approximating to the cry of a bat. Add another coil, and down comes the pace once more, to something like 5000 per second, or about the highest note of a piano. Again and again I load the circuit with magnetisability, and at last the spark has only 600 vibra- tions a second, giving the octave, or perhaps the double octave, above the middle C. One sees clearly why one gets a musical note : the noise of the spark is due to a sudden heating of the air ; now if the heat is oscil- latory, the sound will be oscillatory too, but both will be an octave above the electric oscillation, if I may so express it, because two heat- pulses will accompany every complete electric vibration, the heat production being independent of direction of current. Having thus got the frequency of oscillation down to so manage- able a value, the optical analysis of it presents no difficulty : a simple looking-glass waggled in the hand will suffice to spread out the spark 422 Professor Oliver Lodge [March 8, into a serrated band, just as can be done with a singing or a sensitive flame, a band too of very much the same appearance. Using an ordinary four-square rotating mirror driven electro- magnetically at the rate of some two or three revolutions per second, the band is at the lowest pitch seen to be quite coarsely serrated ; and fine serrations can be seen with four revolutions per second in even the shrill whistling sparks. The only difficulty in seeing these effects is to catch them at the right moment. They are only visible for a minute fraction of a revo- lution, though the band may appear drawn out to some length. The further away the spark is from the mirror, the more drawn out it is, but also the less chance there is of catching its image. With a single observer it is easy to arrange a contact maker on the axle of the mirror which shall bring on the discharge at the right place in the revolution, and the observer may then conveniently watch for the image in a telescope or opera-glass, though at the lower pitches nothing of the kind is necessary. But to show it to a large audience various plans can be adopted. One is to arrange for several sparks instead of one ; another is to multiply images of a single spark by suitably adjusted reflectors, which if they are concave will give magnified images ; another is to use several rotating mirrors ; and indeed I do use two, one adjusted so as to suit the spectators in the gallery. But the best plan that has struck me is to combine an intermittent and an oscillatory discharge. Have the circuit in two branches, one of high resistance so as to give intermittences, the other of ordinary resistance so as to be oscillatory, and let the mirror analyse every constituent of the intermittent discharge into a serrated band. There will thus be not one spark, but several successive sparks, close enough together to sound almost like one, separate enough in the rotating mirror to be visible on all sides at once, and each one analysed into its component alternations. But to achieve this one must have great exciting power. In spite of the power of this magnificent Wimshurst machine, it takes some time to charge uj) our great Leyden battery, and it is tedious waiting for each spark. A Wimshurst does admirably for a single observer, but for a multitude one wants an instrument which shall charge the battery not once only but many times over, with overflows between, and all in the twinkling of an eye. To get this I must abandon my friend Mr. Wimshurst, and return to Michael Faraday. In front of the table is a great induction coil ; its secondary has the resistance needed to give an intermittent dis- charge. The quantity it supplies at a single spark will fill our jars to overflowing several times over. The discharge circuit and all its circumstances shall remain unchanged. [Excite jars by coil.] Eunning over the gamut with this coil now used as our exciter instead of the Wimshurst machine — everything else remaining exactly as it was — you hear the sparks give the same notes as before. 1889.] on the Discharge of a Leyden Jar. 423 but with a slight rattle in addition, indicating intermittence as well as alternation. Rotate the mirror, and everyone should see one or other of the serrated bands of light at nearly every break of the primary current of the coil. [Rotating mirror to analyse sparks.] The musical sparks which I have now shown you were obtained by me during a sj)ecial digression * which I made while examining the effect of discharging a Leyden jar round heavy glass or bisulphide of carbon. The rotation of the plane of polarisation of light by a steady current, or by a magnetic field of any kind properly disposed with respect to the rays of light, is a very familiar one in this place. Perhaps it is known also that it can be done by a Leyden jar current. But 1 do not think it is ; and the fact seems to me very interesting. It is not exactly new — in fact, as things go now it may be almost called old, for it was investigated six or seven years ago by two most highly skilled French experimenters, Messrs. Bichat and Blondlot. But it is exceedingly interesting as showing how short a time, how absolutely no time, is needed by heavy glass to throw itself into the suitable rotatory condition. Some observers have thought they had proved that heavy glass requires time to develop the etitect, by spinning it between the poles of a magnet and seeing the effect decrease ; but their conclusions cannot be right, for the polarised light follows every oscillation in a discharge, the plane of polarisa- tion being waved to and fro as often as 70,000 times a second in my own observation. Very few persons in the world have seen the effect. In fact, I doubt if anyone had seen it a month ago except Messrs. Bichat and Blondlot. But I hope to make it visible to most persons here, though I hardly hope to make it visible to all. Returning to the Wimshurst machine as exciter, I pass a dis- charge round the spiral of wire inclosing this long tube of CS2, and the analysing Nicol being turned to darkness, there may be seen a faint — by those close to not so faint, but a very momentary — restora- tion of light on the screen at every spark. (CS2 tube experiment on screen.) Now I say that this light restoration is also oscillatory. One way of proving this fact is to insert a biquartz between the Nicols. With a steady current it constitutes a sensitive detector of rotation, its sensitive tint turning green on one side and red on the other. But with this oscillatory current a biquartz does absolutely nothing. (Biquartz.) That is one proof. Another is that rotating the analyser either way weakens the extra brightening of the field, and weakens it equally either way. But the most convincing proof is to reflect the light coming * Most likely it was a conversation wMch I had with Sir Wm. Thomson, at Christmas, which caused me to see the interest of getting slow oscillations. My attention has mainly been directed to getting them quick. 424 Prof. 0. Lodge on the Discharge of a Leyden Jar. [March 8, tlirougli the tube upon our rotating mirror, and to look now, not at tlie spark, or not only at the spark, bnt at the fiiint band into which the last residue of light coming through polariscr and tube and analyser is drawn out. (Analyse the light in rotating mirror.) At every discharge this faint streak brightens in places into a beaded band : these are the oscillations of the polarised light : and when examined side by side they are as absolutely synchronous with the oscillations of the spark itself as can be perceived. Rotating the analysing Nicol a little, one sees every alternate bead grow fainter, while the other alternate ones brighten ; thus directly establishing the fact of alternations, as distinct from intermittences. A certain definite rotation will obliterate one set altogether, and make the beading appear twice as coarse, as if it belonged to the octave below. [For further details see * Philosophical Magazine ' for April, 1889.] Out of a multitude of phenomena connected with the Leyden jar discharge I have selected a few only to present to you here this evening. Many more might have been shown, and great numbers more are not at present adapted for presentation to an audience, being only visible with difficulty and close to. An old and trite subject is seen to have in the light of theory an unexpected charm and brilliancy. So it is with a great number of other old familiar facts at the present time. The present is an epoch of astounding activity in physical science. Progress is a thing of months and weeks, almost of days. The long line of isolated ripples of past discovery seem blending into a mighty wave, on the crest of which one begins to discern some oncoming magnificent generalisation. The suspense is becoming feverish, at times almost painful. One feels like a boy who has been long strumming on the silent key-board of a deserted organ, into the chest of which an unseen power begins to blow a vivifying breath. Astonished, he now finds that the touch of a finger elicits a responsive note, and he hesitates, half delighted, half afirightcd, least he be deafened by the chords which it would seem he can now summon forth almost at will. [O.L.] 1889. J Sir James N. Dour/las on Beacon Lights, &c. 425 WEEKLY EVENING MEETING, Friday, March 15, 1889. Sir Frederick Bramwell, Bart. D.C.L. F.R.S. Honorary Secretary and Vice-President, in the Chair. Sir James N. Douglass, F.E.S. M.B.L Beacon LigJits and Fog Signals. It is stated by Samuel Smiles, in his ' Lives of Engineers,' that " with VVinstanley's structure on the Eddystone in 1696, may be said to have commenced the modern engineering efforts," in directing the great sources of power in nature, tor the use and convenience of man ; efforts, which, followed up by Eudyerd, Smeaton, and others, have been so successful in converting hidden dangers into sources of safety, and ensuring the beneficent guidance of the mariner in his trackless path. The famous structure of Smeaton, which had withstood tbe storms of more than half a century with incalculable advantage to mankind, became in course of time a matter of anxiety and w^atchful care to the Corporation of Trinity House, owing to the great tremor of the building with each wave stroke, during heavy westerly storms. The joints of the masonry frequently yielded to the heavy strains, and the sea-water was driven through them to the interior of the building. The upper part of the structure was strengthened with internal iron- work in 1839, and again in 1865. On the last occasion, it was found that the chief mischief was caused by the upward stroke of the heavy seas against the projecting cornice of the lantern gallery, thus lifting this portion of the masonry, together with the lantern above it. Unfortunately, the portion of the gneis rock on which the lighthouse was founded, had become seriously shaken by the heavy sea strokes on the tower, and the rock had thus been seriously undermined at its base. The waves rose during storms considerably above the summit of the lantern, thus frequently eclipsing the light, and altering its distinctive character from a fixed light to an occulting. This matter of distinctive character in a beacon light, was one of little importance at the date of the erection of Smeaton's lighthouse, when coal fires were the only illuminating agents along the coasts ; but with the rapid development of our commerce, and the great increase in the number of coast lights, it has become an absolute necessity that each light maintain a clearly distinctive character. It was, therefore, 426 Sir James N. Douglass [March 15, determined by the Trinity House, in 1877, to erect a new lighthouse at a distance of 120 feet from Smeaton's tower, where a safe and permanent foundation was found, but at a much lower level, which necessitated the laying of a large portion of the foundation masonry below low water. The foundation stone of this work was laid on the 19th August, 1879, by H.E.H. The Duke of Edinburgh, Master of the Trinity House; assisted by H.E.H. The Prince of Wales, an honorary Elder Brother of the Corporation. On the 1st June, 1881, H.E.H. The Master, when passing up Channel in H.M.S. Lively, landed at the rock and laid the last stone of the tower ; and on the 18th May of the following year H.E.H. lighted the lamps, and formally opened the lighthouse. The edifice ■was thus completed within four years from its commencement, at a cost of 59,255?. The work was executed under the immediate direc- tion of the Trinity House and their engineer, and with a saving of 24,000?. on the lowest sum at which it had been found that it could be executed by contract. Every block of granite in the structure, is dovetailed together, both vertically and horizontally, on a system devised by my father, and first adopted at the Hanois rock lighthouse, off the west coast of Guernsey. The illuminating apparatus consists of two superposed oil lamps, each of six concentric wicks ; and of two drums of lenses of 920 mm. focal distance, twelve lenses in each drum. The optical apparatus is specially designed on the system of Dr. John Hopkinson, F.E.S. for a double flashing light, and shows two flashes in quick succession, at intervals of half a minute. Atten- tion has of late been directed to the subject of superposed lights in lighthouses, which became a necessity when several small luminaries had to be substituted for the large coal, or wood, fire of our early lighthouses. The credit of first superposing lighthouse luminaries is doubtless due to Smeaton, who lighted his lantern in 1759 with 24 large tallow candles in two tiers. The idea was followed in 1790 with the first revolving light, established at the St. Agnes lighthouse, Scilly Islands, which consisted of 15 oil lamps and reflectors, arranged in three groups, and in three tiers. The number of the lamps and reflectors at this and other first-class lights, was afterwards extended to 30, and in four tiers. In 1859 Mr. J. W. D. Brown, of Lewisham, proposed superposed lenses for signal and lighthouse lanterns, with a separate light for each tier of lenses. In 1872 Mr. John Wigham, of Dublin, proposed superposed lenses for lighthouses, in conjunction with his large gas flames, and the first application of these was made in 1877, at the Galley Head light- house, County Cork. In 1876 Messrs. Lepaute and Sons, the eminent lighthouse optical engineers of Paris, made successful experi- ments with superposed lenses and mineral oil flames, and one of their apparatus was exhibited at the Paris International Exhibition of 1878. The results of these experiments were given by M. Henry Lepaute, in a paper contributed to the Congress at Havre, in 1877, of the French Association for the Advancement of Science. The Eddy- 1889.] on Beacon Lights and Fog Signals. 427 stone represents the first practical application of superposed lenses of the first order, with oil as the illuminant. The apparatus at the Eddystone is provided with two six wick burners of the Trinity House improved type, and has a minimum intensity for clear weather of about 38,000 candle units, and a maxi- mum intensity of about 160,000 candle units for atmosphere impaired for the transmission of light. The chandelier light in Smeaton's lantern was unaided by optical aj)paratus. I have found by experi- ment that the aggregate intensity of the beam from the 24 candles was G7 candle units nearly. 1 he maximum intensity of the flashes now sent to the mariner is about 2380 times that of the candle beam, while the annual cost for the mineral oil illuminant is about 82 per cent. less. The sound signal for foggy weather consists of two bells of 40 cwt. each, mounted on the lantern gallery, and rung by machinery. If any wind occurs with the fog, the windward bell is sounded. The distinctive character of the signal is two sounds of the bell in quick succession every half minute, thus corresponding with the character of the light signal. The tendency of the curvilinear outline near the base of Smeaton's and of other similar sea towers that have followed it, to elevate the centre of force of heavy waves on the structure, induced me to adopt a cylindrical base for the new lighthouse, which is found to retard the rise of waves on the structure, while it affords a convenient plat- form for the light-keejjers, and adds very considerably to their opportunities for landing and relief. The Town Council and inhabi- tants of Plymouth having expressed a desire that Smeaton's lighthouse should be re-erected on Plymouth Hoe, in lieu of the Trinity House sea mark thereat, the Trinity House, who, as custodians of public money, had no funds available for such a purpose, undertook to deliver to the authorities at Plymouth, at actual cost for labour, the lanterns and the four rooms of the tower. These have been re-erected by public subscription, on a foundation of granite, corresponding nearly with the lower portions of Smeaton's tower, and it is to be hoped that it will be preserved by the town of Plymouth as a monu- meut to the genius of Smeaton, and in commemoration of one of the most successful and beneficent works in civil engineering. It is extremely difiicult to estimate with a fair degree of accuracy the maximum force of the waves with which some of the most exposed of these sea structures may occasionally have to contend. The late eminent lighthouse engineer, Mr. Thomas Stevenson, carried out a long series of experiments with a self-registering instrument he devised for determining the force of sea waves on exposed structures. He found at the Skerry vore rock lighthouse the Atlantic waves there gave an average force for five of the summer months, in 1843-4, of 611 lbs. per square foot. The average result for the six winter months of the same year was 2086 lbs. per square foot, or three times as great as in the summer months. The greatest force registered was on the 29th March, 1845, during a westerly gale, when a pressure Vol XII. (No. 83.) 2 g 428 Sir James N. Doujlass [Marcli 15, of G083 lbs., or 2^ tons nearly, per square foot was recorded. After Smeaton had carefully considered the great defect of the buikling of Kndyerd at the Eddystone, viz. want of weight, he reported that, " if the iitihthouse was to be so contrived as not to give way to the sea, it mnst be made so strong as that the sea must be compelled to give way to the building." Smeaton also had regard to durability as an important element in the structure, for he adds, " in contem})lating the use and benefit of such a structure as this, my ideas of wliat its duration and continued existence ought to be, were not confined within the boundary of one age or two, but extended themselves to look towards a possible perpetuity." Thus Smeaton soon arrived at the firm conviction that his lighthouse must be built of granite, and of this material nearly all lighthouses on exposed tidal rocks have since been constructed, while those on submerged sandbanks are open structures of iron, erected on screw piles or iron cylinders. The screw pile was tlie invention of the late Mr. Alexander Mitchell, of Belfast. We have here a model of the first lighthouse, erected in 1838 on these screw piles, at the Maplin Sands, on the north side of the estuary of the Thames; under the direction of the late James Walker, F.K.S. then Engineer-in-Chief to the Trinity House. A lighthouse on the principle of minimum surface exposed to the force of the waves, of which wo have here a model, was erected on the chief rock of the dangerous group of the Smalls, situated about eighteen-and-a-half miles ofi' Milford Haven, by Mr. John Phillips, a merchant and shipowner of Liverpool. The work was designed and erected under great difficulties by Mr. Henry Whiteside, a native of Liverpool, and a man of great mechanical skill and undaunted courage. Added to his mechanical ability, Whiteside possessed a great love and knowledge of nnisic, and had, previous to the erection of his lighthouse, excelled in the construction of violins, spinnettes, and upright harpsichords. The lighthouse, commenced in 1772, was intended to be erected on eight cast iron pillars, sunk deep into the rock. This material was, how- ever, soon abandoned for English oak, as being more elastic and trustworthy. The work was completed and lighted in 1776, with eight lamps and glass fiiceted reflectors, similar to the one before us. In 1817, sixteen improved lamps and silvered paraboloidal reflectors were substituted for these ; and the lighthouse, although sorely tried by winter storms, was (with the aid of yearly repairs and strengthening) enabled to send forth its beneficent beam until the year 1856, when the Trinity House commenced the erection of a lighthouse of granite, as shown by this model. The vibrations of the ofd wooden structure must have been very considerable with heavy storms, for the lightkeepers occasionally found it sufficient to cause a bucket of water, placed in the living room to spill just half its contents. It was in this lighthouse that the painful circumstance occurred in the year 1802, of the death of one of the lightkeepers. 1889.] on Beacon Lighls and Fog Signals. 429 In those days only two men inhabited the lighthouse at a time ; one of them was taken ill, and the means employed by his companion for olitaining relief proved ineffectual. He hoisted a signal of distress, but owing to stormy weather no landing could be effected, and after many days of extreme suffering, the poor fellow, named Thomas Griffiths, breathed his last, when the survivor, Thomas Howell, fully realised the awful responsibilities of his position ; decom- position would quickly follow, and the atmosphere of the small apartment would be vitiated. The body could not be committed to the sea, as suspicion of murder would probably follow. Howell was a cooper by trade, and he was thus enabled to make a coffin for his dead companion, out of boards obtained from a partition in the apartment. After very great exertion the body was carried to the outer gallery, and there securely lashed to the railing. For three long weeks it occupied this position before the weather moderated, yet night after night Howell faithfully kept his lights brightly burning. When a landing was at last effected, his attenuated form demonstrated the sufferings, both mental and physical, he had under- gone ; indeed, several of his friends failed to recognise him on his return to his home. Since this sad occurrence the Trinity House have always maintained three lightkeepers at their isolated rock stations. The present lighthouse was designed by the late Engineer- in-Chief of the Trinity House, Mr. James Walker, F.E.S. and I had the honour of executing the work 'as resident engineer. The foundation stone was laid on the 26th June, 1857, and the light was exhibited on the 7th August, 1861. The work was completed by the Trinity House, at a cost of 50,125Z., being about twenty-four per cent, under the lowest amount at which it had been ascertained that it could have been executed by contract. Probably the most exposed rock lighthouse is that on the Bishop (the westernmost of the rocks of Scilly), shown on the diagram. Its position is doubtless one of the most important to mariners, warning them as it does of the terrible dangers where, on the 22nd of October, 1707, Sir Cloudesley Shovel, with the Association, Eagle, and Bomney, were lost, with about 2000 men. The Bishop is also the guiding light for the entrances to the English and Bristol Channels. The rock, composed of a very hard pink-coloured granite, is about 153 feet long by 52 feet wide at the level of low water of spring tides. It stands in over twenty fathoms water, is steep-to all round, and is exposed to the full fury of the Atlantic. It was at first feared that the width of the rock was not sufQcient for the base of a stone tower of adequate dimensions to withstand the heavy wave shocks it would have to resist, and an open structure of wrought and cast iron (shown on the diagram) was determined on. The work was jointly designed bv the late Engineer-in- Chief to the Trinity House, and my father, the Superintending Engineer, who afterwards erected the structure, at which I had the honour of acting as Assistant Engineer. The work was commenced in 1847, and at the end of the working 2 G 2 130 Sir James N. Douglass [March 15, season of 1850, the lighthouse was so far completed as to be in readiness for receiving the lantern and the illuminating apparatus ; and it was left with confidence, to resist the storms of the approach- ing winter. But during a very violent storm, between 11 p.m. of the 5th and 3 a.m. on the 6th of the following February, the lighthouse was completely destroyed and swept from the rock. On further con- sideration of the matter, the Trinity House determined, on the recommendation of their engineers, to proceed with a stone structure, and my father was appointed to build the lighthouse, I acting as before as Assistant Engineer. The work was proceeded with in the spring of 1851. In order to obtain the greatest possible diameter of base for the tower that the rock would admit of, it was found necessary to lay a portion of the foundation on the most exposed side of the rock, at the level of one foot below low-water of spring tides ; and, although every possible human effort was made by the leader, and his devoted band of workere, the foundations were not completed until the end of the season of 1852. Soon after this, my brother, Mr. William Douglass, now Engineer-in-Chief to the Commissioners of Irish Lights, succeeded me as assistant engineer at the work. The lighthouse was completed in 1858, and its dioptric fixed oil light of the first order was first exhibited on the 1st of September of that year. Soon after- wards, its exposure to heavy seas during storms, was fully realised. On one occasion the Fog Bell was torn from its bracket at the lantern gallery at 100 feet above high water, and the flag staff with a ladder, which were lashed outside the lantern, were washed away. The tremor of the tower on these occasions was such as to throw articles off' shelves, and several of the large glass prisms of the Dioptric Apparatus were fractured. After some time it was found that several of the external blocks of granite situated a few feet above high water were fractured by the excessive strains on the building. In 1874 the tower was strengthened from top to bottom by heavy iron ties, bolted to the internal surface of the walls ; but, after a violent storm in the winter of 1881, there was evidence of further excessive straining at the face of the lower external blocks of masonry, when the Trinity House, on the advice of their engineer, determined on the re-erection of the lighthouse. This was accomplished, as shown on the diagram, by encasing the existing tower with carefully dovetailed granite masonry, each alternate block of the new granite being dovetailed to the old. The work was one of considerable difficulty, owing to the necessity for maintaining the light throughout the progress ; and the risk to the workmen was great, especially at the upper part of the old tower, owing to the narrow ledge on which the work had to be executed. I am, however, thankful to state that the new Lighthouse has been successfully completed by my son, Mr. W. T. Douglass, who was also my assistant engineer at the Eddystone ; and with the same complete immu- nity from loss of life, or limb, to any person employed, as with the two previous structures on this rock. The optical apparatus consists of two superposed tiers of lenses of the type adopted at the Eddystone, 1889.] on Beacon Lights and Fog Signals. 431 but of larger dimensions, as suggested by the late Mr. Thomas Stevenson, for obtaining greater efficiency with the larger flamed luminaries recently adopted. The apparatus is provided with two Trinity House imj)roved mineral oil burners, and Las a minimum intensity for clear weather of about 80,000 candle units, and a maxi- mum intensity for thick weather of about 513,000 candle units. The character of the light is Double Flashing, showing two flashes, each of four seconds duration, in quick succession at periods of one minute. The flashes of this light, and those of a light lately completed at about eight nautical miles from it, on Round Island, are the most intense yet attained with oil flames for beacon lights ; and it may be stated that, with no other illuminant at present known to science, could these results be carried out within the space available at the Bishop rock, and under the circumstances attending that work. The fog signal recently adopted at this station, in lieu of the bell, is by the electrical explosion of four-ounce charges of gun-cotton, at intervals of five minutes. The apparatus provided for this form of fog signal is shown on the diagram. It consists of a wrought-iron crane (attached to the lantern) which is raised and lowered by a worm wheel and pinion. When the crane is lowered, its end reaches near the gallery, where the lightkeeper suspends the charge of gun-cotton, with its detonator attached, to the electric cable, which is carried along the crane and through the roof of the lantern to a dynamo electric firing machine. Aiter suspending the charge, the jib of the crane is raised to its upper position, when the charge is fired nearly vertically over the glazing of the lantern, and thus without causing damage to it. The large and heavy optical apparatus is rotated automatically by compressed air, which is stored in two vertical steel reservoirs, fixed at the centre of the tower. The air is comj^ressed by a small Davey Safety Motor. A winch, worked by the compressed air, is fixed on the lantern gallery for landing the lightkeepers, stores, &c. The numerous outlying shoals surrounding the shores of this country, particularly ofl:' the east coast, were an early cause of anxiety to those responsible for the guidance of mariners. And in addition to buoys as sea marks by day, floating lights, as guides by night, were found to be a necessity. The first light-vessel was moored at the Nore Sand in 1732, and another near the Dudgeon Shoal in 1736. We have here a model of the latter vessel, from which we may judge of the pluck and hardihood of the crews who manned them ; especi- ally when we remember that there were no chain cables in those days ; the vessel having to be moored with a cable of hemp, which, owing to the constant chafing, occasionally parted during winter storms, when, to save their lives, the crew had to put out another anchor if possible, or set such storm canvas as they could, to keep her off a lee shore, and endeavour to reach a place of safety. The illumi- nating apparatus of these vessels consisted of a small lantern, and 432 Sir James N. Douglass [March 15, flat wick oil lamps, fixed at a yard arm, and here appears to have occurred the first application of a distinctive character to beacon lights, for the Dudgeon was fitted with two lights, one being placed at each arm of the yard. The next light-vessel was placed at the Newarp Shoal in 1790, and in 1795 one was placed at the north end of the Goodwin Sands. The two latter vessels were provided with three fixed lights, and the lanterns were larger and surrounded each mast-head, as shown by the model before us. An improvement was also eifected in these lights by providing each lamp with a silvered reflector. In 1807 the late Mr. Eobert Stevenson, the engineer of the Bell Eock lighthouse, to whom and his successor is due much valuable engineering and optical work connected with coast lighting, designed a larofer lantern to surround the mast, and capable of being lowered to the deck for properly trimming the lamps. Soon after the adop- tion of the system of catoptric illuminations in lighthouses, it was extended to floating lights ; each lamp and reflector was hung in gimballs, to ensure horizontal direction of the beams of light during the pitching and rolling of the vessel. We have here one of these apparatus. The intensity of the beam sent from it was 500 candle units nearly. On the 1st January, 1837, the Trinity House installed the first revolving floating light, at the Swin Middle, and, later in the same year, another on board the Gull light-vessel. The lamps and reflectors were carried on a roller frame surrounding the mast, and rotated through light shafting, by clockwork placed between decks. There w^ere nine lamps and reflectors arranged in three groups, of three each, and thus the collective intensity of each flash was equal to that of three fixed lights, or 1600 candle units nearly. In 1872 the Trinity House further increased the dimensions of the lanterns and reflectors of their floating lights, the lanterns from six to eight feet in diameter, with cylindrical instead of polygonal glazing, and the reflectors from 12 inches to 21 inches diameter at the aperture. These improvements, together with the adoption of improved burners, have effected a considerable increase in the intensity of these lights ; and, during the last two years, a further improvement has been obtained, by the ado23tion of concentric wick burners with more con- densed flames, and of higher illuminating power, by which the intensity of the beam from each reflector has been raised to 5000 candle units ; being just ten times the intensity of the smaller appa- ratus ; while, by the adoption of mineral oil in lieu of colza, the annual cost for the illuminant has been reduced 51 per cent. Dioptric apparatus for light-vessels was proposed by M. Letourneau in 1851, several small fixed light apparatus being in- tended to be employed in each lantern, and arranged nearly in the same way as the reflectors. This arrangement has been adopted in some instances by Messrs. D. and T. Stevenson, engineers to the Commissioners of Northern Lighthouses, and by the engineers of the 1889.] on Beacon Lights and Fog Signals. 433 French Lighthouse service ; but, for efficiency, and adaptability to meet the rough duty to which floating lights are occasionally sub- jected, in stormy weather and collisions, this system has been found to be inferior for this service to the catoptric. An interesting experiment was recently made by the Mersey Docks and Harbour Board with the electric arc light, on board one of their light-vessels at the entrance of the Mersey, but unfortunately it did not jDrove successful. The present difficulties exj^erienced afloat with this powerful illuminant will doubtless be overcome, and it will be found to be, as in lighthouses, by far the most efficient illuminant for some special stations, where a higher intensity tLan can be obtained with flame luminaries is demanded. Experiments have been in pro- gress during the past two years at the " sunk " light- vessel, off the coast of Essex, for maintaining electrical telegraphic communication with the shore for reporting wrecks and casualties in the locality. This vessel is connected with the Post Office at Walton-on-Naze, through nine miles of cable. The instruments adopted are the Wheatstone A.B.C. " Morse," and the Gower Bell telej^hone — the telephone for the first time for this purpose on board a vessel at sea, and its efficiency has been found to be so perfect, that it is preferred by the operators to the telegraphic instruments. Many difficulties have been experienced in maintaining reliable communication during stormy weather, owing to consequent wear and tear of the connections with the vessel, but the system, whiclrwas designed and carried out by the Telegraphic Construction and Maintenance Company, is now working satisfactorily. Unfortunately, however, it is found to be too costly for adoption, except in very special cases. In 1876, Mr. Julius Pintsch, of Berlin, patented in this country his system of illuminating buoys or other floating bodies by com- pressed oil gas, and in 1878 one of these buoys was experimentally tried at sea with success by the Trinity House. The system is similar to that previously adopted by Mr. Pintsch with great success in the lighting of railway carriages, but with the addition for buojs of a specially constructed lantern, containing a small cylindrical lens for a fixed light. Through the kindness of the Pintsch's Lighting Comjjany we have here one of these a23paratus, producing an intensity in the beam of about twenty candle units. With the charge of gas contained in the buoy the light is shown continuously, night and day, from two to four months, according to the dimensions of the buoy, without re-filling or requiring any other attention, except occasional cleaning of the lens and the glazing of the' lantern. In 1883, Mr. William B. Eickman patented a very ingenious addition to this apparatus for producing occulting or flashing light. The apparatus is automatically worked by the issuing compressed gas on its way from the buoy to the burner. After passing the regulator, where the pressure of the gas is reduced for burning, it enters a cylindrical chamber, covered with a diaj^hragm of very flexible specially jirepurcd leather ; this diax)hragm, on being slightly raised by the inflowing 434 Sir James N. Douglass [March 15, gas, commnuicates motion to a lever, which, assisted by a spiral spring, closes the inlet pipe, and opens at the same time the passage to the burner. As the gas passes on and is consumed at the burner the diaphragm, by its own weight, assisted by the springs, sinks, and, touching the lever, closes the outlet aperture to the burner, and, at the same moment, opens the inlet of the gas from the buoy for another charge. Thus the light is extinguished while the gas is entering the chamber and until the latter is re-filled, when the passage from the buoy is again closed by the rising of the diaphragm. A small pilot jet is constantly burning to ensure the re-ignition of the gas when re-admitted to the burner. It is evident that several cha- racteristic distinctions of light may be obtained by modifications of this ingenious apparatus. About 150 buoys lighted on the Pintsch system are already rendering valuable service to mariners in various parts of the world. For the more important stations at sea, where light-vessels are now employed, the system is considered to be yet wantinsc in that trustworthiness which should be the leadincj cha- racteristic of all coast lighting. Very important experiments have lately been made by the Lighthouse Board of the United States, at their general depot at Tompkiusville, New York, with buoys lighted electrically by glow lamps, operated through submarine con- ductors from the shore. These experiments have ju'oved so successful that an installation for marking the Gedney's Channel, entrance of Lower Bay, New York Harbour, with six buoys and 100 candle glow lamps, was lighted on the 7th of November last. Gas buoys were considered inapplicable for this special case, owing to their form and size rendering them liable to break adrift, particularly when struck by floating ice or passing vessels. The buoy adopted for the service consists of a spar 46 feet long, having its lower end shackled direct to a heavy iron sinker, resting on the bottom. At the upper end the buoy is fitted with an iron cage, enclosing a heavy glass jar, in which is placed the glow lamp of 100 candle units intensity. The cable is secured by wire staples, in a deep groove cut in the buoy, and covered by a strip of wood. For a distance of several feet at the lower end of the buoy the cable is closely served with iron wire, over which is wound spun yarn, to prevent injury from chafing on the shackle and sinker. The central station on shore, with steam engines and dynamos in duplicate, is on Sandy Hook, at a distance from the extreme buoys of about three nautical miles. The installation is re- ported to be working continuously and successfully. For auxiliary or port lights on shore, where no collisions can occur, the Pintsch gas system is found to be very perfect. At Broadness, on the Thames, near Gravesend, the Trinity House erected, in 1855, an automatic lighthouse illuminated on Pintsch's system, as shown by the diagram. This small lighthouse shows a single flashing light, at periods of ten seconds, the flashes having an intensity of 500 candle units. The flashes and eclipses are produced with perfect regularity by special clockwork, which alsu turns on the gas supply to the burner at 1889.] on Beacon Lights and Fog Signals. 435 Bimset and off again at sunrise. It is also arranged for periodic ad- justment, f(jr the lengthening and shortening of the nights throughout the year. This automatic light is in the charge of a boatman, who visits it once a week, when he cleans and adjusts the apparatus, and cleans the glazing of the lantern. An automatic lighthouse similar to that at Broadness has Leon lately installed at Sunderland by the Kiver Wear Commissioners, on a pier which is inaccessible in stonny weather. In 1881-82 several beacons automatically lighted by petro- leum spirit, on the system of Herr Lindberg and Herr Lyth, of Stockholm, were established by the Swedish Lighthouse authorities, and are reported to be working efficiently. In 1885, a beacon or automatic liglithouse on this system was installed by the Trinity House on the Thames, near Gravescnd, and has been found to work efficiently. The light is occulting at periods of about two seconds ; the ocoultations are produced by an opaque screen rotated around the light, by the ascending currents of heated air from the lamp acting on a horizontal fan. As there is no governor to the apparatus the periods of the occultations are subject to slight errors compared with those of tlie gas light controlled by clockwork. In 184d an iron beacon, lighted by a glow lamp and the current from a secondary battery, was erected on a tidal rock near Cadiz. Contact is made and broken by a small clock, which runs for 28 days, and causes the light to flash for five seconds at periods of half a minute. The clock is also arranged for eclipsing the light" between sunrise and sunset. The apparatus is the invention of Don Isas Lavoden, of Cadiz, to whom I am indebted for kindly showing me the light in action when on a visit to Cadiz in 1885. There is every probability that auto- matic beacons, lighted either by electricity, gas, or petroleum spirit, will, in consequence of their economy in maintenance, be extensively adopted in the future. Coal and wood fires, the flames produced by the combustion of tallow, nearly all the animal, vegetable, and mineral oils, coal and oil gas, and the lime light, have been employed from time to time in lighthouse illumination, and last but not least, the electric light. None of tliese illuminants have received such universal application in all positions both asliore and afloat as mineral oil at the present moment, and justly so, when we consider its efficiency and economy for the purpose. So recently as 1822, the last beacon coal fire in this country was replaced by a catoptric oil light, at Saint Bees light- house, on the coast of Cumberland. We have here diagrams of two of these coal fire beacons, one of them designed and erected by Smeaton in 1767 on his lighthouse at the Spurn Point, on the east side of the entrance to the Humber. So late as 1845 sperm oil was entirely used in the lighthouses and light-vessels of the Trinity House; but, shortly afterwards, colza w^as adopted with the same efficiency, and with a saving in annual cost of about 44 per cent. In 1861, experi- ments were made by the Trinity House for determining the relative efficiency and economy of colza and mineral oil for lighthouse illumi- 436 Sir James N. Douglass [March 15, nation ; but owing to the imj^erfect refinement of the best samples of the latter then procurable in the market, together with its high price, the result of the investigation was not so satisfactory as to justify a change from colza. In 1869 the price of mineral oil of good illumi- nating quality and safe flashing point, was found to be procurable at about half the j)rice of colza, when the Trinity House determined to make a further series of exj)eriments, and by these it was ascertained that, with a few simjDle modifications of the Argand burners then in use, they were rendered very efficient for the purpose, it was also found tliat these burners were thus considerably improved for the combustion of colza. A change from colza to mineral oil was then commenced, and mineral oil is now generally adopted in the light- houses and light-vessels of the Trinity House service, and with even greater economy than was at first anticij^ated ; the price of this illuminant being now rather less than one-third that of colza. The most powerful oil burner then in use was one of four concentric wicks, the joint production of Arago and Fresuel, and adopted by the French lighthouse authorities about the year 1825, in conjunction with the then new diojjtric system of optical apparatus of Fresnel. The standard intensity of the combined flames of this burner, one of which we have here, was 260 candle units. A farther development was made, during the experiments of the Trinity House in 1871, by increasing the number of wicks from four to six, which more than doubled the intensity of the light, while effecting a condensation of the luminary j^er unit of focal area, or in other words improved the optical efficiency 70 per cent. We have here also one of these burners. I have since devised an Argand burner for the combustion of all illuminating gases and oils, whereby still further condensation of the flames, together with greater intensity and economy of combustion, is obtained, and the glass chimney is protected from breakage. These imj^rovements are efi'ected by a special arrangement and distribution of the air currents through the rings of flame, and between them and the glass chimney. (See Models.) We are thus enabled on this system to increase the dimensions of lighthouse burners, for gas and oil, for ten or more rings of flame. With ten rings we obtain an aggregate intensity, when burning cannel gas and good mineral oil, of consider- ably over 2000 candle units, while the improved efficiency of the luminary for oj^tical condensation of the radiant light, per unit of focal area, as compared mth the luminary of our Fresnel four-wick oil burner, has been in each case increased 109 per cent. With reference to the jDcrfect combustion of these highly condensed flames I may state that the efficiency for gas is exactly double that of the London standard Argand burner, viz. when con;^uming gas of the London standard of 16 candles, the light produced is at the rate of 6 • 4, instead of 3 • 2, candles per cubic foot. In addition to a single ring gas burner of this type we have two burners of ten rings of flame, and models of their flames, one for gas and the other for mineral oil. These burners are all of the Trinity House new pattern, both 1889.] on Beacon Lights and Fog Signals. 437 gas and oil, and they are of the same general arrangement for com- bustion, except that the oil burner is j^i'ovided with cotton wicks. Both produce flames of nearly the same form, dimensions, intensity, and colour. The first application of coal gas to lighthouse illumination was made at the Troon lighthouse, Ayrshire, in 1827 ; and in 1847 it was adopted at the Hartlepool lighthouse, Durham ; when for the first time it was employed in combination with dioptric apparatus of the first order of Fresnel. The slow progress made with coal gas in lighthouses, except for harbour lights, where the gas could be obtained in their vicinity, as at Hartlepool, was chiefly due to the great cost incurred in the manufacture of the small quantity required, and at the usual isolated positions occupied by coast ligLthouses, involving extra cost both for labour and for the extra transport of the coal. In 1865 the attention of lighthouse authorities was directed to gas as an illuminant for lighthouses by Mr. John R. Wigham, of Dublin, whoso system was tried in that year at the Howth Bailey lighthouse, Dublin Bay. The gas burner of Mr. Wigham, one of which we have here, consists of seven concentric rings, of single flat-flame burners, amount- ing in the aggregate to 108. The burner is used without a glass chimney, and thus there is no appreciable condensation of the group of flames for their employment at the focus of optical apparatus, and the relative aggregate intensity of the ^seven rings of flat flames per unit of focal area, as compared with the four concentric flames of the old four- wick oil burner of Fresnel, are only 2^ per cent, higher than the latter. The burner has five powers for varying states of the atmosphere. For the minimum intensity 28 jets are employed, and with the whole 108 jets there is a maximum aggregate intensity of the flames, with cannel gas, of about 2500 candle units. Several lighthouses on the coast of Ireland have been illuminated with gas on the system of Mr. Wigham, and two at Haisboro, on the coast of Norfolk. In 1878 Mr. Wigham installed at the Galley Head light- house, County Cork, his system of superposed gas flames and group flashing light, which consisted of four of his large gas burners vertically superposed. In conjunction with these were four tiers of first order annular lenses, eight in each tier. By successive lowering and raising of the gas flames at the focus of each tier of lenses, he produced his group flashing distinction. This light shows, at periods of one minute, instead of the usual single flash from each lens, or vertical group of lenses, a group of short flashes, varying in number, between six and seven. The unavoidable uncertainty with this system in the number of flashes contained in each group is unfor- tunate for the mariner, who, with the continued increase in the number of coast lights, requires the utmost precision in the distinctive character adopted for each. In 1857 an experimental trial of the first magneto-electric machine of Holmes, for the practical application of the electric light, was made 438 Sir James N. Douglass [March 15, by the Trinity House at Blackwall, under the direction, and to the great delight, of their scientific adviser, Faraday ; and after a series of experiments, the satisfactory report of Faraday encouraged the Trinity House to order a practical trial of a pair of the Holmes machines. The trial was made at the South Foreland high lighthouse, by Faraday and Holmes, on the 8th of December, 1858, when electricity w^as found to be a formidable rival to oil and gas for lighthouse illumination, and this position it maintains to the 23resent day. The trials of this arc light were made at the focus of the first order dioptric apparatus for oil light, which was very imperfect for the purpose, but they w^ere sufiiciently encouraging to lead the Trinity House, under the advice of Faraday, to proceed further with the electric light for lighthouses. Faraday thus wrote in his report to the Trinity House : " I beg to state that, in my opinion. Professor Holmes has practically established the fitness and sufficiency of the magneto-electric light for lighthouse purposes, so far as its nature and management are concerned. The light produced is powerful beyond any other that I have yet seen so applied, and in principle may be accumulated to any degree; its regularity in the lantern is great, its management easy, and its care there may be confided to attentive keepers of the ordinary intellect and knowledge." These truly j)rophetic words of Faraday have been entirely realised ; electricity still stands foremost in the illumination of our coasts, and aj)pears destined to be one of the greatest blessings ever conferred on humanity, and more esj)ecially on '' those who go down to the sea in shijjs." On the 1st of February, 1862, Holmes's machines and aj)i3aratus for the electric liglit were installed at Dungeness lighthouse, and in 1863 the French lighthouse authorities followed, by an installation of the Alliance Comj)any's magneto-electric machines and apparatus for fixed lights, at each of the two lighthouses at Cape La Heve. We have here the first dioptric apparatus designed and manufactured by Messrs. Chance Bros. & Co. of Birmingham, for the electric fixed light at Dungeness. We have also one of the Holmes lamps emj)loyed there. The lamp used at the previous experiments was devised by M. Duboscq, of Paris. This lamp of Holmes is similar to those of Duboscq and Serrin, excepting that the upjDcr and low^er carbons and holders are balanced and regulated through pulleys and small catgut cords, instead of by rack and pinions. The carbons are ^-inch square, and the mean intensity of the light in the arc was 670 candle units nearly. We have here samples of the carbons employed from time to time in the develop- ment of the electric light in lighthouses ; we have also aBergot lamp, fitted with the fluted form of carbons I have recently devised. They are of the dimensions now in use at the Saint Catherine's lighthouse, and are giving a mean intensity in the arc of 40,000 candle units. Cylindrical compressed carbons were soon manufactured for the electric light, and were found to be more homogeneous in quality and the flickering of the light less than with the original square carbons, which were simply sawn from the residual carbon of gas retorts ; but 1889.] on Beacon Lights and Fog Signals. 439 there was still the objectionable crater at the points, whether direct or alternating currents were employed, involving flickering from the incessant shifting of position at the points. A considerable loss of radiant light was also involved, particularly when condensing it optically. The flickering was somewhat reduced by an improvement of Messrs. Siemens, in providing the carbons with a graphite core, but with the increasing powers of currents and in the necessary dimensions of carbons the results were far from satisfactory. With the fluted form of carbon shown on the diagram the formation of the crater is prevented, and the arc is held centrally at the points of the carbons; there is thus, in addition to comparatively steady light, nearly uniform radiation in azimuth, and over a greater vertical angle for optical condensiition. It now appears to me, after some practical experience with this form of carbon, that it is impossible to determine a practical limit to the dimensions of carbons that may be efficiently emj)loyed. With carbons of the actual size shown on the diagram an intensity of about a million candle units should be produced in the arc, and about 150 millions of candle units in the condensed flashes from the optical apparatus of the dimensions now employed for oil and gas flames in lighthouses. Such an intensity is about 400 times that possible at the focus of such aj^paratus with a flame luminary. Such results as these were probably in the mind of Faraday when he reported that " in principle this light may be accumulated to any degree." Flashes of the great intensity here referred to could only be employed in atmosphere impaired for the transmission of light. In clear weather they would be found to be far too dazzling to the eyes of the mariner, while an intensity of about 50,000 candle units is found to be sufficient for his guidance, and in thick fog no possible intensity can be of practical value for navigation. There are, how- ever, various gradations of impaired atmosphere, between clear weather and thick fog, in which the highest available intensity is doubtless desirable at many important landfall stations for obtaining the greatest possible range of visibility. On the other hand, at the majority of stations in narrow waters, the maximum intensity now obtained with flame light is found to be more generally efficient for navigation than higher intensities. In 1881 the question of the relative merits of the three light- house illuminants — electricity, gas, and mineral oil — was receiving the attention of the lighthouse authorities of this country, whicli resulted in the Trinity House accepting the responsibility of carrying out an investigation at the South Foreland, of universal importance to the mariner. In the photometrical and electrical portions of this work the Trinity House were aided by the labours of Professor Harold Dixon, F.R.S. and Professor W. Grylls Adams, F.E.S. which contributed very largely to the success of the investigation. The experiments were carried on during a period of over twelve months, and a vast amount of very valuable evidence was collected from numerous 440 Sir James N. Douglass [Marcli 15, observers, trained and untrained, scientific and practical. The report of the Committee was presented to both Houses of Parliament, by command of Her Majesty, in 1885. The final conclusions of the Committee are given in the following words : " That for the ordinary necessities of lighthouse illumination, mineral oil is the most suitable and economical illuminant, and that for salient headlands, important landfalls, and places where a very powerful light is required, elec- tricity ofiers the greatest advantages." I have already referred to the necessity, with the present develop- ment of maritime commerce, that every beacon light maintain a clearly distinctive character. When the optically unaided flames of coal fires were the illuminants of our lighthouses, distinctive cha- racters, owing to the small number of lights then employed, were of little importance, and the only distinctions then j)ossible were the costly ones of single, double, or triple lighthouses at one station ; but with the enormous increase that has since occurred in the floating commerce of the world, and with the necessary laws now in operation requiring all vessels to carry lights, trustworthy individuality in coast beacon lights has become a positive necessity. Until very recently the distinctive characters consisted of the following : viz. — fixed white, fixed red, revolving white, revolving red, and revolving white and red alternately. The revolving lights showed a flash at periods of 10 seconds, 20 seconds, 30 seconds, one minute, 2 minutes, 3 minutes, and 4 minutes. There were also intermittent or occulting lights, having an eclipse at periods of half-a-minute, one minute, or 2 minutes. It is now generally considered that fixed lights are no longer trustworthy coast signals, owing to their liability to confusion with other lights, both ashore and afloat. It is also considered that in these days of high speed vessels the period of the character of a coast light should not if possible exceed half-a-minute. The revolving or flashing class of lights are probably the most valuable, on account of their superior intensity, as compared with the fixed or occulting class, the light during the intervals of eclipse being condensed into each succeeding flash by the revolving lenses or reflectors, and thus, with the same expenditure of the illuminant, an intensity is obtained in the flashes of five to eight times that of the fixed or occulting class. Where local dangers are required to be guarded by coloured sectors of danger light with well-defined limits, this can only be accomplished with the fixed or occulting class of lights. We will illustrate this with the model before us. We will also show the clear difierence of character, not generally realised, between flashing and occulting lights. A system of occulting lights for lighthouses was proposed by the late Charles Babbage, F.E.S. in 1857 ; but as it excluded the flashing or most powerful of the existing lights, it did not receive much favour from lighthouse authorities. And in 1872, ' Distinctive Characters for Coast Lights,' was the subject of a paper by Sir William Thomson, F.R.S. at the Brighton Meeting 1889.] on Beacon Lights and Fog Signals. 441 of the Britisli Association for the Advancement of Science, when he directed attention to the extreme importance of ready identification of lights at sea, and proposed the use of quick-flashing lights, their flashes being of longer or shorter duration ; the short and long flashes representing the dot and dash of the Morse alphabet as used in telegra]3hy. It was found, however, that the number of symbols in one alphabetical code would not be sufficient, on a thickly lighted coast, to ensure individuality, and render each distinction perfectly trustworthy. Further, that very raj)id repetition of each symbol is not required by the mariner, and would involve loss of accumulative power in the flashes, besides incurring unnecessary wear and tear in rotating heavy oj)tical apparatus. Yet much is to be done in the direction of simple distinction. At the Montreal Meeting of the British Association, in 1884, I submitted a paper on 'Improvements in Coast Signals,' in which were suggested two aljDhabetical codes of flashing lights, and one of occulting, all having the same period of the symbol, viz. half-a-minute. In one of the codes of flashing lights long and short flashes were proposed, as previously by Sir William Thomson, and, in the other, there were proposed white and red flashes. In the occulting series, long and short eclipses were proposed to be substituted for the long and short or white and red flashes of the flashing codes. The system has the advantage of ajppli- cation to all existing lighthouse apparatus, and many lights have been altered to selected symbols of eaclr of these series. Little was ever accomplished in the way of warning or guidance to the mariner during fog, until about the middle of this century. Pre- viously, a few bells had been established at lighthouses in this country and abroad, and gongs of Chinese manufacture had been in general use on board our light-vessels, but both instruments are now acknowledged to be wanting in the efficiency now demanded in fog, to meet the requirements of navigation. The first imj)ortant improve- ment in fog signals, for the service of mariners, was made by the late Mr. Daboll in 1851, who submitted to the United States Light- house Board, in that year, a powerful trumpet, sounded by air, com- pressed by horse-power. The apparatus was installed at Beaver Tail Point, Rhode Island, and the favourable results obtained with it stimulated Mr. Daboll, under the encouragement of the United States Lighthouse Authorities, to the further development of the apparatus ;• and ultimately, he employed Ericsson's Caloric Engine, as the motive power, with automatic gearing for regulating the blasts. In 1854, some experiments on difterent means of producing sounds for coast signals were made by the engineers of the French Lighthouse Depart- ment, and in 1861-2, MM. Le Gros and Saint Ange Allard, of the Corps des Ponts et Chaussees, conducted a series of experiments upon the sound of bells, and the various methods of striking them. In 1862, Mr. Daboll submitted his improved fog trumpet apparatus of about three horse-power in the blasts, to the Trinity House, who, under the 442 Sir James N. Douglass [March 15, advice of Faraday, made experimental trials with it in London, and afterwards gave it a practical trial at the Dungeness lighthouse, where experiments were made with it against bells, guns, and a reed fog horn of Professor Holmes, whose services have been already referred to in connection with the first practical application of the electric light. This fog horn of Holmes was sounded by steam, direct from one of the boilers employed at the station for his electric lio^ht. The results of these experiments were in favour of Daboll's trumpet, and in 1869, one of these instruments was installed on board the Newarp light- vessel. In the same year, Holmes, having effected further improvements with his steam horn, his apparatus was fitted on board two light-vessels and sent out to the coast of China, where they were found to give great satisfaction, as compared with gong signals. In 1863 a committee of the British Association for the Advancement of Science memorialised the President of the Board of Trade, with the view of inducing him to institute a series of experiments upon fog signals. The memorial, after briefly setting forth a statement of the nature and importance of the subject, described what was then known respecting it, and several suggestions were made relative to the nature of the experi- ments recommended. The proposal does not appear to have been favourably entertained by the authorities to whom it was referred, and the experiments were not carried out. In 1864 a series of experiments was undertaken by a commission appointed by the Lighthouse Board of the United States to determine the relative powers of various fog signals which were submitted to the notice of the Board. In 1872, a committee of the Trinity House, with the object of ascertaining the actual efficiency of various fog signals then in operation on the North American Continent, visited the United States and Canada, where they found in service Daboll's trumpets, steam whistles, and siren apparatus, devised by Mr. Felix Brown, of Progress Works, New York, sounded by steam and compressed air. From the report of the Trinity House Committee, it does not appear that they were greatly impressed with this instrument, but j)i'obably they had not an opportunity of testing its real merits, as compared with other signals. The late Professor Henry, of the United States Lighthouse Board, entertained a very high opinion of the siren, and on his advice, and the urgent recommendation of Professor Tyndall, one of these instruments was sent to England and included in the fog signal experiments at the South Foreland in 1873-4. This in- vestigation was carried out by the Trinity House, with the view of obtaining definite knowledge as to the relative merits of various sound-producing instruments then in use, and also of ascer- taining how the proj)agation of sound is affected by meteorological phenomena. Professor Tyndall, as scientific adviser of the Trinity House, conducted the investigation, aided by a committee of the Trinity House and their engineer. These experiments were extended over a lengthened period, in all conditions of weather, and the well- 1889.] on Beacon Lir/hfs and For/ Sh/uaJ^. 443 known scientific and practical results obtained, togetlier with the ascertained relative merits of sound-producing instruments for tha service of the mariner, have proved to be of the highest scientific interest and practical importance. The investigation at the South Foreland was followed up by the Trinity House with further explosivv'? fog signal experiments, in which they were assisted by the authori- ties at Woolwich Arsenal, with guns of various forms, weight of charges, and descriptions of gunpowder. The powders tested were — (1) fine grain, (2) larger grain, (3) rifle large grain, and (4) pebble. The result placed the sound-producing powers of these powders exactly in the order above stated ; the fine grain, or most rapidly burning powder, gave indisputably the loudest sound, while the report of the slowly burning pebble powder, was weakest of all. Here, again, the greater value of increased rapidity of combustion in producing sound, was demonstrated. It was found that charges of gun-cotton yielded reports louder at all ranges than equal chargew of the best gunpowder ; and further experiments proved the ex- plosion of half-a-pound of gun-cotton gave a sound equal in intensity to that, produced by three pounds of the best gunpowder. These ijivestigations led the Trinity House to adopt gun-cotton for fog signals at isolated stations on rocks and shoals, as already described, where, from want of space, it had hitherto been possible to apply nothing better than a bell, or gong. Of all the sound signals now employed, for the warning and guidance of mariners during fog, viz. bells, gongs, guns, whistles, reed trumpets, sirens, and sounds produced by the explosion of gun-cotton, the blasts of the siren, and explosions of gun-cotton, have been found to be the most efficient for coast fog signals ; therefore these signals have received the greatest care and attention in their development. The siren doubtless ranks first, for stations wherever it can be applied, chiefly on account of its economy in maintenance, and the facility it affords for giving prolonged blasts of any desired intensity or pitch, and thus providing any number of trustworthy distinctive characters that may be required to ensure individuality in the signal. Sirens are now employed at many floating and shore stations of the Trinity House, and one recently installed at Saint Catherine's Light- house, Isle of Wight, of the automatic Holmes type, of which we have here a model, absorbs during its blast not less than 600 horse-jDOwer. The audibility of the blasts of this instrument may be considered to be trustworthy at a range of two miles under all conditions of foggy atmosphere on the sea surface over which it is intended to be sounded. It is very desirable that for many landport stations a greater trust- worthy range be provided for the mariner, but this can only be afforded by such increased power as would be required for a more powerful electric light installation to serve the mariner in other gradations of thick atmosphere. A very important improvement and economy have lately been effected in the sirens of the Trinity House by rendering them always instantaneously available for Vol. XIT. (No.'.S3.) 2 h 444 Sir James N. Douglass on Beacon Lights, &c. [March 15, sounding at their maximum power. This is accomplished by the storage of a sufficient quantity of compressed air to work the siren during the time required for raising steam and starting the engine. The signal is thus always in readiness for immediate action, day or niglit, with an expenditure of fuel only incurred during fog, which on the coast of this country does not exceed an average of 440 hours per annum. The experience yet gained with the most powerful fog signals now in use, although these apparatus far exceed in efficiency, for the service of the mariner in fog, any light that science can provide, is not yet so satisfactory as we could desire. The best signal is, as I have already stated, occasionally not heard, under certain atmospheric conditions, beyond two miles ; while under other conditions, not apparent to the mariner, the signal is distinctly audible at ten miles : therefore there is much to be desired in the development of the means of propagating sound waves, and in ren- dering them audible to the manner. In conclusion, I would venture to state that, with the best light and sound signals that can be provided, there are conditions of the atmosphere in which the mariner will earnestly look and listen in vain for the desired light or sound signal, and he must still, under such circumstances, exercise caution in availing himself of their guidance, and never neglect the assistance always at hand of his old trusty friend the lead. [J. N. D.] WEEKLY EVENING MEETING, Friday, March 22, 1889. Colonel J. A. Grant, C.B. C.S.I. F.R.S. Vice-President, in the Chair. Eadweard Muybridge, Esq. Tlie Science of Animal Locomotion in its Relation to design in Art, (Illustrated by the Zoopraxiscope.) [No Abstract.] WEEKLY EVENING MEETING, Friday, March 29, 1889. William Ceookes, Esq. F.E.S. Vice-President, in the Chair. A. Gordon Salamon, Esq. F.C.S. 3LBJ. Yeast. [Abstract deferred.] 1889.] General Monthly Meeting. 445 GENERAL MONTHLY MEETING, Monday, April 1, 1889. Sir James Crichton Browne, M.D. LL.D. F.R.S. Vice-President, in the Chair. Septimus Felix Beevor, Esq. B.A. Professor J. A. Fleming, M.A. D.Sc. John Langston, Esq. J.P. F.R.C.S. Major S. Flood Page, were elected Members of the Royal Institution. The Special Thanks of the Members were returned to Joseph Davis, Esq. for his present of an American " Forecast " Barometer. The following Arrangements for the Lectures after Easter were announced : — Jean Paul Richter, Esq. Ph.D. — Three Lectures on The Italian Renais- sance Painters : their associations, their education, and their employments (with Illustrations) ; on Tuesdays, April 30, May 7, 14. Professor E. Ray Lankester, M.A. LL.D. F.R.S. — Four Lectures on Some Recent Biological Discoveries; on Tuesdays, May 21, 28, June 4, 11. Eadweard MijybridCtE, Esq. of the University of Pennsylvania — Two Lec- tures on The Science of Animal Locomotion in its Relation to Design in Art (illustrated by the Zoopraxiscope) ; on Thursdays, May 2, 9. Professor Dew^ar, M.A. F.R.S. M.B.I. Fullerian Professor of Chemistry, R.I. Jacksonian Professor of Natural Experimental Philosophy, Cambridge- Five Experimental Lectures on Chemical Affinjty ; on Thursdays, May 16, 23 30, June 6, 13. Joseph Bennett, Esq. — Four Lectures on The Origin and Development of Opera in England (with Musical Illustrations) ; on Saturdays, May 4, 11, 18, 25. Professor W. Knight, LL.D. Professor of Moral Philosophy at the University -)f St. Andrews — Three Lectures on I. The Classification op the Sciences, Historical and Critical; II. Idealism and Experience, in Philosophy and Literature ; III. Idealism and Experience, in Art and Life (the Tyndall Lectures); on Saturdays, June 1, 8, 15. The Presents received since the last Meeting were laid on tlie ,able, and the thanks of the Members returned for the same, viz : — FROM Hie Governor-General of India — Geological Survey of India : Records, Vol. XXI Part 4. 8vo. 1889. \merican Pliilosophical Society — Proceedings, Vol. XXV. No. 128. 8vo. 1888, irhuthnot, F. F. Esq. M.B.I. — The Beharistan (Abode of Spring). By Jtimi. 8vo' Benares, 1887. The Gulistan (Rose Garden of Sadi). 8vo. Benares, 1888. {static Society, Royal {China Branch) — Journal, Vol. XXIII. No. 1. 8vo. 1888. istronomical Society, Royal — Monthly Notices, Vol. XLIX. No. 4. 8vo. 1889. !an]:ers, Institute of — Journal, Vol. X. Part 3. 8vo. 1889. latavia Observatory —Jiamf all in the East Indian Archipelago, 1887. 8vo. 1888. Magnetical and Meteorological Observations, Vols. VIII. and X. fol. 1888. hitish Architects, Royal Institute of — Proceedings, 1888-9, Nos. 10, 11. 4to. ■amhriflge Philosophical Society — Transactions, Vol. XIV. Part 3. 4to. 1889. 'hemicai Society — Journal for March, 1889. 8vo. Imrch, Professor A. H. M.A. F.B.S. M.B.I, {the Aiithor)— Guide to the Museum of Roman Remains at Cirencester. 7th ed. 8vo. 1889. ivil Engineers' Institution — Minutes of Proceedings, Vol. XCV. 8vo. 1889, linical Society — Transactions, Vol. XXI. 8vo. 1888. hix : Societe de Borda — Bulletin, Quatorzieme Annee, I'' Tremestre. 8vo. 1889. 2 H 2 446 General Montlily Meeting. [April 1, Editors — American Journal of Science for March, 1889. 8vo. Analyst for March, 1889. 8vo. Atheuseum for March, 1889. 4to. Chemical News for March, 1889. 4to. Chemist and Druggist for March, 1889. Sro. Electrical Engineer for March, 1889. fol. Engineer for March, 1889. fol. Engineering for March, 1889. fol. Horological Journal for March, 1889. 8vo, Industries for March, 1889. fol. Iron for March, 1889. 4to. Murray's Magazine for March, 1889. 8vo. Nature for March, 1889. 4to. Photographic News for March, 1889. 8vo. Revue Scientifique for March, 1889. 4to. Telegraphic Journtil for March, 1889. 8vo. Zoophilist for March, 1889. 4to. Florence, Bihlioteca Nazionale Centrale — Bolletino, Num. 77. 8vo. 1889. Geographical Society, Royal — Proceedings, New Series, Vol. XI. No. 3. 8vo. 1889. Geological Institute, Imperial, Vienna — Verhandlungen, 1889, No. 2. 8vo. Hamilton, Colonel A. C. R.E. M.R.I, (the Author)— Map of the World oti a new projection, showing Zoogeographieal regions. (2 copies.) 1889. Menshrugghe, G. van der, Esq. {the Author) — L'Influence de la Capillnrite dans la Pensiinetrie. 8vo. 1888. Contribution a la Theorie du Siphon. 8vo. 1889. Miller, W. J. 0. Esq. (the Registrar)— Medical Register, 1889. 8vo. Dentists' Register, 1889. 8vo. Medical Students' Register, 1889. 8vo. Fourtli Report of General Medical Council. 8vo. 1888. Odontological Society of Great Britain — Transactions, Vol. XXI. No. 5. New Series. 8vo. 1889. Pharmaceutical Society of Great Britain — Journal, March, 1889. 8vo. Royal Colonial Institute— Troceedings, Vols. I. II. IV. VI. to XIX. 8vo. 1869-88. Royal Society of London — Proceedings, No. 276. 8vo. 1889. Saxon Society of Sciences, Royal — Mathematisch-phvsische Classe : Abhandhing. Band XV. Nos. 1, 2. 8vo. 1888. Berichte, 1888, Nos. 1, 2. 8vo. 1889. Philologisch-historisehen Classe: Berichte, 1888, Nos. 3, 4. 8vo. 1889. Siemens, Alexander, Esq. M.R.I, (for the Executors) — Scientific Works of Sir William Siemens. Kdited by E. F. Bamber. 3 vols. 8vo. 1889. Society of Architects — Proceedings, Vol. I. No. 8. 8vo. 1889. Society of ^rfs— Journal. March, 1889. 8vo. Society of Chemical Industry— ionrnoX, Vol. VIII. Nos. 1. 2. 8vo. 1889. Thompson, Sir Henry, F.R.C.S. M.R.I. (the Author) — Modern Cremation: its History and Practice. 8vo. 1889. United States Geological Survey — Mineral Resources of the United States, 1885. 8vo. 1886. Bulletins, Nos. 40-47. 8vo. 1887-8. Wright and Co. Messrs. J. (the Publishers) — The Medical Annual for 1889. 8vo. Lectures on Bright's Disease. By R. Saundby. 8vo. 1889. WEEKLY EVENING MEETING, Friday, April 5, 1889. Colonel J. A. Grant, C.B. C.S.I. F.E.S. Vice-President, in the Chair. The Rev. Canon Ainger, M.A. True and False Humour in Literature. [No A})straot.] 1889.] The Right Hon. Lord Bayleigh on Iridescent Crystals, 4:41 WEEKLY EVENING MEETING, Friday, April 12, 1889. Sir Frederick Bramwell, Bart. D.C.L. F.R.S. Honorary Secretary and Vice-President, in the Chair. The Right Hon. Lord Eayleigh, M.A. D.C.L. LL.D. F.R.S. M.R.L PUOFESSOK OF NATURAL PHILOSOPHY, R.I. Iridescent Crystals. The principal subject of the lecture is the peculiar coloured reflection observed in certain specimens of chlorate of j^otash. Reflection implies » high degree of discontinuity. In some cases, as in decomposed glass, and probably in opals, the discontinuity is due to the inter- position of layers of air ; but, as was jJi'oved by Stokes, in the case of 3hlorate crystals the discontinuity is that known as twinning. The 5eat of the colour is a very thin layer in the interior of the crystal and parallel to its faces. The following laws were discovered by Stokes : — (1) If one of the crystalline plates be turned round in its own plane, without alteration of the angle of incidence, the peculiar reflec- tion vanishes twice in a revolution, viz. when the plane of incidence 3oincides with the plane of symmetry of the crystal. [Shown.] (2) As the angle of incidence is increased the reflected light )ecomes brighter and rises in refrangibility. [Shown.] (3) The colours are not due to absorption, the transmitted light )eing strictly complementary to tlie reflected. (4) The coloured light is not polarised. It is produced indifibr- ntly, whether the incident light be common light or light polarised ci any plane, and is seen whether the reflected light be viewed directly r through a Nicol's prism turned in any way. [Shown.] (5) The spectrum of the reflected light is frequently found to onsist almost entirely of a comparatively narrow band. When the ngle of incidence is increased, the band moves in the direction of acreasing refrangibility, and at the same time increases rapidly in 'idth. In many cases the reflection appears to be almost total. In order to project these phenomena a crystal is prepared by .menting a smooth face to a strip of glass, whose sides are not quite arallel. The white reflection from the anterior face of the glass can len be separated from the real subject of the experiment. A very remarkable feature in the reflected light remains to be oticed. If the angle of incidence be small, and if the incident light Ub The Bujlit Hon. Lord Rcujh'iijh [April 12, be polarised in or perpendicularly to the plane of incidence, the reflected light is polarised in the opposite manner. [Shown.] Similar phenomena, except that the reflection is white, are exhibited by crystals prepared in a manner described by Madan. If the crystal be treated beyond a certain point the peculiar reflection disappears, but returns upon cooling. [Shown.] In all these cases there can be little doubt that the reflection takes place at twin surfaces, the theory of such reflection* reproducing with remarkable exactness most of the features above described. In order to explain the vigour and purity of the colour reflected in certain crystals, it is necessary to suppose that there are a considerable number of twin surfaces disposed at approximate equal intervals. At each angle of incidence there would be a particular wave length for which the phases of the several reflections are in agreement. The selection of light of a particular wave length would thus take place upon the same principle as in diffraction spectra, and might reach a liigh degree of perfection. In illustration of this explanation an acoustical analogue is exhibited. The successive twin planes are imitated by parallel and equidistant discs of muslin (Figs. 1 and 2j stretched upon brass rings BIRO CALL ©sensitive: flame Detail of Lazy -tongs and mounted (with the aid of three lazy-tongs arrangements), so that there is but one degree of freedom to move, and that of such a character as to vary the interval between the discs without disturbing their equidistance and parallelism. The source of sound is a bird-call, giving a pure tone of high pitch (inaudible), and the percipient is a high pressure flame issuing from a burner so oriented that the direct waves are without influence ' Phil. Mag.' Sept. 188S. 1889.] on Iridescent Crystals. 449 upon tlio flame.* But the waves reflected from the muslin arrive in the effective direction, and if of sufficient intensity induce flaring. The experiment consists in showing that the action depends upon the distance between the discs. If the distance be such that the waves reflected from the several discs co-operate, f the flame flares, but for intermediate adjustments recovers its equilibrium. For full success it is necessary that the reflective power of a single disc be neither too great nor too small. A somewhat open fabric appears suitable. It was shown by Brewster that certain natural specimens of Iceland spar are traversed by thin twin strata. A convergent beam, reflected at a nearly grazing incidence from the twin planes, depicts upon the screen an arc of light, which is interrupted by a dark spot corresponding to the plane of symmetry. [ Shown.] A similar experi- ment may be made with small rhombs in which twin layers have been developed by mechanical force after the manner of Keusch. The light reflected from fiery opals has been shown by Crookes to possess in many cases a high degree of purity, rivalling in this respect the reflection from chlorate of potash. The explanation is to be sought in a periodic stratified structure. But the other features differ widely in the two cases. There is here no semicircular evanes- cence, as the specimen is rotated in azimuth. On the contrary, the coloured light transmitted perpendicularly through a thin plate of opal undergoes no change when the gem is turned round in its own plane. Ihis appears to prove tliat the alternate states are not related to one another as twin crystals. More probably the alternate strata are of air, as in decomposed glass. The brilliancy of opals is said to be readily affected by atmos2>heric conditions. * See 'Proc. Eoy. Inst.' Jan. 1888. t If the reflection were perpendicular, the interval between successive discs would be equal to the half wave-length, or to some multiple of this. 150 Auiiiud Mcct'tuy. [May L ANNUAL MEETING, Wednesday, May 1, 1889. Sir James Ckichton Buowne, M.D. LL.D. F.K.S. Vice-President, in the Chair. The Annual Report of the Committee of Visitors for the year 1888, testifying to the continued prosperity and eflScient management of the Institution, was read and adopted. The Real and Funded Property now amounts to above 81,000/. entirely derived from the Contributions and Donations of the Members. Forty-five new Members were elected in 1888. Sixty-four Lectures and Nineteen Evening Discourses wcra delivered in 1888. The Books and Pamphlets presented in 1888 amounted to about 296 volumes, making, with 570 volumes (including Periodicals bound) purchased by the Managers, a total of 8G6 volumes added to the Library in the year Thanks were voted to the President, Treasurer, and the Honorary Secretary, to the Committees of Managers and Visitors, and to the Professors, for their valuable services to the Institution during the 2)ast year. The following Gentlemen were unanimously elected as Officers for the ensuing year : President — The Duke of Northumberland, K.G. D.C.L. LL.D. Tkeasdrer — Henry Pollock, Esq. Secretary — Sir Frederick Bramwell, Bart. D.C.L. F.R.S. M. Inst. C.E. Managers. Sir Frederick Abel, C.B. D.C.L. F.R.S. Sir James Crichton Browne, M.D. LL.D. F.R.S. WiUiam Crookes, Esq. F.R.S. Francis Galton, Esq. M.A. F.R.S. Colonel James A. Grant, C.B. C.S.L F.R.S. The Rt.Hon. Sir Wm. R. Grove, M.A. D.C.L. F.R.S. William Huggins, Esq. D.C.L. LL.D. F.R.S. David Edward Hughes, Esq, F.R.S. Rev, John Macnaught, M.A, William Henry Preece, Esq. F.R.S, M, Inst, C.E. William 0. Priestlev, M.D. LL.D. F.L.S, .John Rae, M.D. LL.D. F.R.S. William Chandler Roberts-Austen, Esq. F.R.S. Lord Arthur Russell. Basil Woodd Smith, Esq. F.R.A.S. Visitors. William Anderson, Esq. M.Inst, C.E. John Birkett, Esq. F.R.C.S. Alfred Carpmael, Esq. Ernest H. Goold, Esq. F.Z.S, Charles Hawksley, Esq. M. Inst. C.E. John Hopkinson, Esq, M,A. F.R.S. M.Inst. C.I Victor Horsley, Esq. F.R.S, F,R.C.S. Ludwig Mond, Esq. F.C.S. Edward Pollock, Esq, Lachlan Mackintosh Rate, Esq. M.A. Arthur William Riicker, Esq, M.A. F.R,S. John Bell Sedgwick, Esq. J.P, F,R.G,S. Thomas Edward Thorpe, Esq. Ph.D. F.R.S. Thomas Tyrer, Esq, F.C.S. James Wimshurst, Esq. 1889.1 Sir Henri/ Hoscue on Ahiiuinium. 451 WEEKLY EVENING MEETING, Friday, May 3, 1889. Sir Frederick Bramwell, Bart. D.C.L. F.E.S. Honorary Secretary aud Vice-President, in tlie Chair. {Sir Henry Eoscoe, M.P. D.C.L. LL.D. V.P.K.S. Aluminium, Chemists of many lands have c(mtributed to our knowledge of the metal aluminium. Davy, in 1807, tried in vain to reduce alumina by means of the electric current. Oerstedt, the Dane, in 1824, pointed out that the metal could be obtained by treating the chloride with an alkali metal ; this was accomplished in Germany by Wohler in 1827, and more completely in 1845, whilst in 1854, Bunsen showed how the metal can be obtained by electrolysis. But it is to France, by the hands of Henri St. Claire Deville, in the same year, that the honour belongs of having first j^repared aluminium in a state of purity, and of obtaining it on a scale which enabled its valuable properties to be re- cognised and made available, and the bar of "silver-white metal from clay," was one of the chemical wonders in the first Paris Exhibition of 1855. Now England and America step in, and I have this evening to relate the important changes which further investigation has effected in the metallurgy of aluminium. The process suggested by Oerstedt, carried out by Wohler, and modified by Deville, remains in princi23le unchanged. The metal is prepared, as before, by a reduction of the double chloride of aluminium and sodium, by means of metallic sodium in presence of cryolite ; and it is therefore not so much a description of a new reaction as of improvements of old ones of which 1 have to speak. I may perhaps be allowed to remind my hearers that more than 33 years ago, Mr. Barlow, then secretary to the Institution, delivered a discourse, in the presence of M. Deville, on the 2)roperties and mode of j)reparation of aluminium, then a novelty. He stated that the metal Vs as then sold at the rate of 3/. per ounce, and the exhibition of a small ingot, cast in the laboratory by M. Deville, was considered remarkable. As indicating the jDrogress since made, I may remark that the metal is now sold at 20s. per lb., and manufactured by the ton, by the Aluminium Company, at their works at Old bury, near Birmingham. The improvements which have been made in this manufacture by the zeal and energy of Mr. Castner, an American metallurgist, are of so important a character, that the process may properly be termed the Deville-Castner process. The production of aluminium previous to 1887, probably did not exceed 10,000 lbs. per annum, whilst the i>rice at that time was very i52 Sir Hcnn/ Boscoe FMay 3, liigli. To attain even this prodnctiou required that at least 100.000 lbs, of double chloride, and -iO.OOO lbs. of sodium should be manu- factured annually. From these figures an idea of the magnitude of the undertaking assumed by the Aluminium Company may be esti- mated, when we learn that they erected works having an annual CAcc?n^£ ^roi .j9/Aut IS inches in width at their widest part and abour 3 feet high, and are made in two portions, the lower one t»eing actually in the form of a crucible, while the -pper one is provided with an upright stem and a protruduig hollow ,rm. This part of the apparatus is known as the cover. In com- 4.54 Sir Henry Koscoe [May o, mencing the operation, these covers are raised in the heated furnace through apertures provided in the floor of the heated chamber, and are then fastened in their place by an attachment adjusted to the stem ; the hollow arm extends outside the furnace. Directly below each aperture in the bottom of the furnace are situated the hydraulic lifts ; attached to the top of which are the platforms upon which are placed the crucibles to be raised into the furnace. Attached to the hydraulic lifts are the usual reversing valves for lowering or raising, and the platform is of such a size as, when raised, completely to fill the bottom aperture of the furnace. The charged crucible, being placed upon the platform, is raised into its position, the edges meeting those of the cover, forming an aii*-tight joint which prevents the escape of gas and vapour from the vessel during reduction, except by the hollow arm provided for this purpose. The natural expansion of the iron vessels is accommodated by the water-pressure in the hydraulic lifts, so that the joint of the cover and crucible are not disturbed until it is intended to lower the lift for the purpose of removing the crucible. The length of time required for the first operation of reduction and distillation is about two hours. At the end of this time the crucibles are lowered, taken from the platforms by a large pair of tongs on wheels, carried to a dumping pit, and thrown on their side. The residue is cleaned out, and the hot pot, being again gripped by the tongs, is taken back to the furnace. On its way, the charge of alkali and reducing material is thrown in. It is again placed on the lift and raised in position against the edges of the cover. The time consumed in making the change is IJ minute, and it only requires about seven minutes to draw, empty, recharge, and replace the five crucibles in each furnace. In this manner the crucibles retain the greater amount of their heat, so that the operation of reduction and distillation now only requires one hour and ten minutes. Each of the four furnaces, of five crucibles each, when in operation, are drawn alternately, so that the process is carried on night and day. Attached to the protruding hollow arm from the cover are the condensers, which are of a peculiar pattern specially adapted to this process, being quite different from those formerly used. They are about 5 inches in diameter, and nearly 3 feet long, and have a small opening in the bottom about 20 inches from the nozzle. The bottom of these condensers is so inclined that the metal condensed from the vapour issuing from the crucible during reduction, flows down and out into a small pot placed directly below this opening. The uncondensed gases escape from the condenser at the further end, and burn with the characteristic sodium flame. The condensers are also provided with a small hinged door at the further end, by means of which the workmen from time to time may look in to observe how the distillation is progressing. Previous to drawing the crucibles from the furnace for the purpose of emptying and recharging, the Bmall pots each containing the distilled metal are removed, and empty 1889. 1 on Aluminium, 455 ones substituted. Those removed eacli contain on an average about 6 lbs. of metal, and are taken directly to the sodium casting shop, where it is melted and cast, either into large bars ready to be used for making aluminium, or in smaller sticks to be sold. Special care is taken to keep the temperature of the furnaces at about 1000^ C, and the gas and air valves are carefully regulated, so as to maintain as even a temperature as j^ossible. The covers remain in the furnace from Sunday night to Saturday afternoon, and the crucibles are kept in use until they are worn out, when new ones are substituted without interrupting the general running of the furnace. A furnace in operation requires 250 lbs. of caustic soda every one hour and ten minutes, and yields in the same time 30 lbs. of sodium, and about 240 lbs. of crude carbonate of soda. With the four furnaces at work 120 lbs. of sodium can be made every 70 minutes, or over a ton in the 24 hours. The residual carbonate, on treatment with lime in the usual manner, yields two-thirds of the original amount of caustic operated upon. The sodium, after being cast, is saturated with kerosene oil, and stored in large tanks holding several tons, placed in rooms specially designed both for security against either fire or water. Chlorine Manufacture. This part of the works is connected with the adjacent ^vorks of Messrs. Chance Bros, by a large gutta-percha pipe, by means of which from time to time hydrochloric acid is supplied direct into the large storage cisterns, from which it is used as desired for making the chlorine. For the preparation of the chlorine gas needed in making the chloride, the usual method is employed ; that is, hydrochloric acid and manganese dioxide are heated together, when chlorine gas is evolved with effervescence, and is led away by earthenware and lead pipes to large lead-lined gasometers, where it is stored. The materials for the generation of the chlorine are brought together in large tanks, or stills, built up out of great sandstone slabs, having rubber joints, and the heating is effected by the injection of steam. The evolution of gas, at first rapid, becomes gradually slower, and at last stops ; the hydrochloric acid and manganese dioxide being converted into chlorine and manganous chloride. This last com- pound remains dissolved in the " spent still liquor " and is recon- verted into manganese dioxide, to be used over again, by Weldon's Manganese Eecovery Process, Owing to the difficulty of keeping up a regular supply of chlorine under a constant pressure directly from the stills, in order that the quantity passed into the sixty different retorts in which the double-chloride is made can be regulated and fed as desired, four large gasometers were erected. Each of these is capable of holding 1,000 cubic feet of gas, and is completely lined with lead, as are all the connecting mains, &c., this being the only available metal which withstands the corrosive action of clilorine. The 456 Sir Henry Boscoe [^lay 3, gasometers are filled in turn from the stills, the chlorine consumed being taken direct from a gasometer under a regular pressure until it is exhausted ; the valves being changed, the supply is taken from another holder, the emptied one being refilled from the still. Manufacture of the Double Chloride. Twelve large regenerative gas furnaces are used for heating, and in each of these are fixed five horizontal fire-clay retorts about 10 ft. in length, into which the mixture for making the double chloride is placed. These furnaces have been built in two rows, six on a side, the clear passage-way down the centre of the building, which is about 250 ft. long, being 50 ft. in width. Above this central passage is the staging carrying the large lead-mains for the supply of the chlorine coming from the gasometers. Opposite each retort, and attached to the main, are situated the regulating valves, connected w^ith lead and earthenware pipes, for the regulation and passage of the chlorine to each retort. The valves are of peculiar design, and have been so constructed that the chlorine is made to pass through a certain deptli of liquid, which not only by opposing a certain pressure allows a known quantity of gas to pass in a given time, but also prevents any return from the retort into the main, should an increase of pressure be suddenly developed in the retorts. The mixture with which the retorts are charged is made by grinding together hydrate of alumina, salt, and charcoal. This mixture is then moistened with water, which partially dissolves the salt, and thrown into a pug mill of the usual type for making drain pipes, excepting that the mass is forced out into solid cylin- drical lengths upon a platform alongside of which a workman is stationed with a large knife, by means of which the material is cut into lengths of about 3 inches each. These are then piled on top of the large furnaces to dry. In a few hours they have sufficiently hardened to allow of their being handled. They are then transferred to large wagons, and are ready to be used in charging the retorts. The success of this process is in a great measure dependent — 1st, on the proportionate mixture of materials ; 2nd, on the tem- perature of the furnace ; 3rd, on the quantity of chlorine introduced in a given time ; and 4th, on the actual construction of the retorts, I am, however, not at liberty to discuss the details of this part of the process, which have only a commercial interest. In carrying on the operation, the furnaces or retorts, when at the proper temperature, are charged by throwing in the balls until they are quite full, the fronts are then sealed up, and the charge allowed to remain undis- turbed for about four hours, during which time the water of the alumina hydrate is completely expelled. At the end of this time the valves on the chlorine main are opened, and the gas is allowed to pass into the charged retorts. In the rear of each retort, and con- nected therewith by means of an earthenware pipe, are the condenser 1889.] on Aluminium. 457 boxes, which are built in brick. These boxes are provided with openings or doors, and also with earthenware pipes connected with a small flue for carrying off the uncondensed vapours to the large chimney. At first the chlorine passed into each retort is all absorbed by the charge, and only carbonic oxide escapes into the o])en boxes, where it burns. After a certain time, however, dense fumes are evolved, and the boxes are then closed, while the connecting pipe between the box and the small flue serves to carry off the uncon- densed vapours to the chimney. The reaction which takes place is as follows : — AlA + 2NaCl + 3C + 6C1 = 2AlCl3NaCl + 3C0. The chlorine is passed in for about 72 hours in varying quantity, the boxes at the back being opened from time to time by the work- men to ascertain the progress of the distillation. At the end of the time mentioned the chlorine valves are closed and the boxes at the back of the furnace are all thrown open. The crude double chloride, as distilled from the retorts, condenses in the connecting pipe and trickles down into the boxes, where it solidifies in large irregular masses. The yield from a bench of five retorts will average from 1,600 to 1,800 lbs., which is not far from the theoretical quantity. After the removal of the crude chloride from the condenser boxes, the retorts are opened at their charging end, and the residue, which consists of a small quantity of alumina, charcoal, and salt, is raked out and remixed in certain proportions with fresh material, to be used over again. The furnace is immediately re-charged and the same operations repeated, so that from each furnace upwards of 3,500 lbs. of chloride are obtained weekly. With ten of the twelve furnaces always at work the plant is easily capable of i^roducing 30,000 lbs. of chloride per week, or 1,500,000 lbs. per annum. Owing to the presence of iron, both in the materials used (viz., charcoal, alumina, &c.) and in the fireclay composing the retorts, the distilled chloride always contains a varying j^roportion of this metal in the form of ferrous and ferric chlorides. When it is remembered that it requires 10 lbs. of this chloride to j^roduce 1 lb. of aluminium by reduction, it will be quite apparent how materially a very small percentage of iron in the chloride will influence the quality of the resulting metal. I may say that, exercising the utmost care as to the purity of the alumina and the charcoal used, and after having the retorts made of special fireclay containing only a very small per- centage of iron, it was found almost impossible to produce upon a large scale a chloride containing less than 0 * 3 per cent, of iron. This crude double chloride, as it is now called at the works, is highly deliquescent, and varies in colour from a light yellow to a dark red. The variation in colour is not so much due to the varying per- centage of iron contained as to the relative proportion of ferric or ferrous chlorides present, and although a sample may be either very dark or quite light, it may still contain only a small percentage of I 458 Sir Henry JRosfoe [May 3, iron if it be present as ferric salt, or a very large percentage if it is in the ferrous condition. Even when exercising all possible precau- tions, the average analysis of the crude double chloride shows about 0 • 4 per cent, of iron. The metal subsequently made from this chloride therefore never contained much less than about 5 per cent, of iron, and, as this quantity greatly injures the capacity of aluminium for drawing into wire, rolling, &c., the metal thus obtained required to be refined. This was successfully accomplished by Mr. Castner and his able assistant Mr. Cullen, and for some time all the metal made was refined, the iron being lowered to about 2 per cent. The process, however, was difficult to carry out, and required careful manipulation, but as it then seemed the only remedy for efioctively removing the iron, it was adopted and carried on for some time quite successfully, until another invention of Mr. Castner rendered it totally unnecessary. This consisted in purifying the double chloride before reduction. I cannot now explain this process, but I am able to show some of the product. This purified chloride, or pure double chloride, is, as you see, quite white, and is far less deliquescent than the crude, so that it is quite reasonable to infer that this most undesirable property is greatly due to the former presence of iron chlorides. I have seen large quantities containing upwards of Ih per cent, of iron, or 150 lbs. to 10,000 of the chloride, completely purified from iron in a few minutes, so that, whilst the substance before treatment was wholly unfit for the preparation of aluminium, owing to the i^resence of iron, the result was, like the sample exhibited, a mass containing only 1 lb. of iron in 10,000, or O'Ol per cent. The process is extremely simple, and adds little or no appreciable cost to the final product. After treatment, this pure chloride is melted in large iron pots and run into drums similar to those used for storing caustic soda. As far as I am aware, it was geneially believed to be an impossibility to remove the iron from anhydrous double chloride of aluminium and sodium, and few if any chemists have ever seen a pure white double chloride. Aluminium Manufacture. I now come to the final stage of the process, viz., the reduction of the pure double chloride by sodium. This is effected, not in a tube of Bohemian glass, as shown in Mr. Barlow's lecture in 1856, but iu a large reverberatory furnace, having an inclined hearth about 6 feet square, the inclination beinjj towards the front of the furnace, through which are several openings at different heights. The pure chloride is ground together with cryolite in about the proportions of two to one, and is then carried to a staging erected above the reducing furnace. The sodium, in large slabs or blocks, is run through a machine similar to an ordinary tobacco-cutting machine, where it is cut into small thin slices ; it is then also transferred to the staging above the reducing furnace. ^°^^-] on Aluminium. 459 tI,Pv^W.!^f ff '''' T, °°'^ *^''°r '''''° " '*•■§« revolving drum, wben urLrl r . r";" \^^ '"'^"'- ^^"^ '^'■"■^ '^^•"g opened and partially J~r f tr. /'"^ ''""'' ?' "''^ '° "^« '''^^"•'^'J temperat,u-e, the wd ^' furnace are all closed to prevent the access of ai •, the Ce ft,rn^?r f '' ''"1^^ '^":T"y "'^'' "^« '^^■^t''^ °f ti« dearth. mfen,W^ r f '' "^'"""^^^ "'"^ ^"§''' '^°PP«''«' ^°'^ tl^^ough these Xtnf f»l ', "^', '' introduced as quickly as possibfe. The hauefies ''^Z^^^ ^^T'^'^'^''''^^^^ ^"'^ "^^ whole charge quickly liqueies. At the end of a certain time the heating gas is a -^^- '^ '■'' '--^^^ betJet ^^^i:'Jz^:^,::-^^z^^ - ''-^ As no reliable information has ever been malp T^nKl,V* ^r. +i • itfwTe'tm'irT^ ^'""^'^ '^'^^^rZ^ 1 ''as aware, fiom information gained at the works at Oldbury that Loo nt'o?7r '° ^' KT'^t'^" of contained iron materially^kS Its pomt of fusion, and it has been undoubtedly due to this cause tl.nt such wide limits are given for the melting pint Under these c ir cumstances two samples were forwarded for testing, ofwhich No 1 containing i per cent, of iron, had a melting point of 700' C ; wlfe^,as No 2, containing 5 per cent, of iron, does not melt at 700=> aTd {flonTnor '^"' *'''" temperature but undergoes incipie:;! According to Faraday, aluminium ranks very hi<.h amon- metallic conductors of heat and electricity, and he fo .nd that i? conducted heat better than either silver or Conner ThT^^l'^ i: . s also very high, which accounts for lengihT Le'r e^S f^r Tn Chemically, ,ts properties are well worthy of study Air, eitlier wet or dry, has absolutely no effect on aluminium at the ~7,Hr''^'r'"ri '"'."^f p^p*'--'^ - -^y posses"" iTa 1'': li^ht^o;, 7t, ^^'^'•/^'?'J tl^e pure metal in mass undergo^es only light oxidatMm even at the melting point of platinum. ^ •;thri?-i % iT^T' '",'"'" ^"^^'^ '° " current of oxygen burns 'letl h/ '"'*■ '^'"'f ^^'^^ "§'''• (Experiment shown) If the i2i,^r P"?'."'"'^'^ ^^^ '^r^'^^' o'' it '^'^atever, even at a red-heat IIa^H «™»P0i>uds also are without action on it while ith Vl/'°"rr"T^"°""^ "^'"■'y "" »^'^1« '-""Id be discolou ed tef sal^f^l^nditSr""'^"' ^'°™ "^^"°"^"^^^ ^-"^ '""'"'"^"'^ ■ate^a:^pt^^:rit-ih tLit ^;^si;-r rdrochloric acid or caustic alka^. Heatil'in'a'ttaosph^f ^f 2 I 2 462 Sir Henry Boscoe [^^'^7 3, chlorine it bnrns ^yith a vivid liglit, producing aluminium cliloride. (Experiment shown). In connection with the subject it may be of interest to state the true melting point of the double chloride of aluminium and sodium, which has always been given at 170' to 180' C, but which !Mr. Baker, the chemist to the works, finds lies between 125-' and loO' C. Uses of Ahuniniiun. Its uses, unalloyed, have heretofore been greatly restricted. This is, I believe, alone owing to its former high price, for no metal possessing the properties of aluminium could help coming into larger use if its cost were moderate. Much has been said as to the impossi- bility of soldering it being against its popular use, but I believe that this difficulty will now soon be overcome. The following are a few of the purposes to which it is at present put : telescope tubes, marine glasses, eye glasses and sextants, especially on account of its lightness. Fine w^re for the making of hice. embroidery, &c. Leaf in the place of silver leaf, sabre sheaths, sword handles, ike, statuettes and -works of art, jewellery and delicate physical aj^paratus, culinary utensils, harness fittings, metallic parts of solders' uniforms, dental purposes, surgical instruments, reflectors (it not being tarnished by the pro- ducts of combustion), photographic apparatus, aeronautical and engineering purposes, and especially for the making of alloys. Alloys of Aluminium. The most important alloys of alummium are those made with copper. These alloys were first prepared by Dr. Percy, in England, and now give promise of being largely used. The alloy produced by the addition of 10 per cent, of aluminium to copper, the maximum amount that can be used to produce a satisfactory alloy, is known as aluminium bronze. Bronzes, however, are made which contain smaller amounts of aluminium, possessing in a degree the valuable properties of the 10 per cent, bronze. According to the jjercentage of aluminium up to 10 per cent., the colour varies from red gold to pale yellow. The 10 per cent, alloy takes a fine polish, and has the colour of jewellers' gold. The 5 per cent, alloy is not quite so hard, the colour being very similar to that of pure gold. I am indebted to Prof. Pioberts Austen for a splendid specimen of crystallised gold, as also for a mould in which the gold at the mint is usually cast, and in this I have had prepared ingots of the 10 and 5 per cent, alloy, so that a comparison may be made of the colour of these with a gold ingot cast in the same mould, for the loan of which I have to thank Messrs. Johnson, Matthey, & Co., all of which are before you. I have also ingots of the same size, of pure aluminium, from which au idea of the relative weights of gold and aluminium may be obtained. To arrive at perfection in the making of these alloys, not only is 1889.] en Aluminium, 463 it required that the aluminium used should be of good quality, but also that the copper must be of the very best obtainable. For this purpose only the best brands of Lake Superior copper should be used. Inferior brands of copper or any impurities in the alloy give poor results. The alloys all possess a good colour, polish well, keep their colour far better than all other copper alloys, are extremely malleable and ductile, can be worked either hot or cold, easily engraved, the higher grades have an elasticity exceeding steel, are easily cast into complicated objects, do not lose in remelting, and are possessed of great strength, dependent, of course, on the purity and percentage of contained aluminium. The 10 per cent, alloy, when cast, has a tensile strength of between 70,000 and 80,000 lbs. per square inch, but when hammered or worked, the test exceeds 100,000 lbs. (A sample shown broke at 105,000 lbs.). An attempt to enumerate either the present uses or the possible future commercial value of these alloys is beyond my present purpose. I may, however, remark that they are not only adapted to take the place of bronze, brass, and steel, but they so far sui-pass all of those metals, both physically and chemically, as to make their extended use assured. (Sheets, rods, tubes, wire, and ingots shown.) But even a more important uso of aluminium seems to be its em- ployment in the iron industry, of which it promises shortly to become a valuable factor, owing to certain effects which it produces when present, even in the most minute proportions. Experiments are now being carried on at numerous iron and steelworks, in England, on the Continent, and in America. The results so far attained are greatly at variance, for whilst in the majority of cases the improvements made have encouraged the continuance of the trials, in others the result has not been satisfactory. On this point I would wish to say to those who may contemplate making use of aluminium in this direction, that it would be advisable before trying their experiments to ascertain whether the aluminium alloy they may purchase actually contains any aluminium at all, for some of the so-called aluminium alloys contain little or no aluminium, and this may doubtless account for the negative results obtained. Again, others contain such varying proportions of carbon, silicon, and other impurities, as to render their use highly objectionable. It seems to be a prevailing idea with some people, that because aluminium is so light compared with iron, that they cannot be directly alloyed, and furthermore, that for the same reason, alloys made by the direct melting together of the two metals would not be equal to an alloy where both metals are reduced together. Now, of course, this is not the case, and the statement has been put forward by those who were only able to make the alloys in one way. Aluminium added to molten iron and steel lowers their melting points, consequently increases the fluidity of the metal, and causes it to run easily into moulds and set there, without entrapping air and other gases, which serve to form blow-holes and similar imper- 464 Sir Henry Hoscoe on Aluminium. [May 3, fectioiis. It is already used by a large number of steel founders, and seems to render the production of sound steel castings more certain and easy than is otherwise possible. One of the most remarkable applications of this property which aluminium possesses of lowering the melting-point of iron has been made use of by Mr. Nordenfelt in the production of castings of wrought iron. Aluminium forms alloys w^ith most other metal-^, and although ea6h possess peculiar properties which in the future may be utilised, at present they are but little used. In conclusion, I beg to call your attention to the wood models on the table, one being representative of aluminium, the other aluminium bronze. The originals of these models are now in the Paris Exhibi tion, each weighing 1000 lbs. With regard to aluminium bronze, I cannot speak positively, but the block of pure aluminium is un- doubtedly the largest casting ever made in this most wonderful metal. I have to thank the Directors of the Aluminium Company, and especially Mr. Castner, for furnishing me with the interesting series of specimens of raw and manufactured metal for illustrating my discourse. [H. E. K.] i GENEIUL MONTHLY MEETING, Monday, May 6, 1889..J Siii James Ckichtok Bkowne, M.D. LL.D. E.E.b'. Vice-President, in the Chair. The following Vice-Presidents for the ensuing year were announced : — Sir Frederick Abel, C.B. D.C.L. F.E.S. Sir James Crichton Browne, M.D. LL.D. F.E.S. William Crookes, Esq. F.E.S. Colonel James A. Grant, C.B. C.S.I. F.E.S. William Huggins, Esq. D.C.L. LL.D. F.E.S. John Eae, M.D. LL.D. F.E.S. Henry Pollock, Esq. Treasurer. Sir Frederick Bramwell, Bart. D.C.L. F.E.S. Hon. Secretary. 1889.] General Monilily Meeting. 465 W. L. A. Bartlett Biirdett-Coutts, Esq. M.P. James J. Fellows, Esq. Uemy Parry Gilbey, Esq. Colonel George Edward Gouraud, Henry Arthur Hunt, Esq. Thomas Stuart Kennedy, Esq. J.P. Arthur Lucas, Esq. Major- General Eardley Maitland, C.B. R.A. Frederick J^chwann, Esq. Colonel William Brooke Thomson, Charles Wilson Vincent, Esq. F.R.S.E. F.C.S. F.I.C. E. W. Wallace, Esq. Ernest Watney, Esq. were elected Members of the Royal Institution. The decease of Dr. Warren de la Eue, D.C.L. F.R.S. Manager and Vice-President, on April 19th, was announced from the Chair. The following Resolution passed by the Managers at their Meeting this day was read : — Besolved, "That the Managers of tlie Eoyal Institution of Great Britain have with much sorrow to record their profouiid sense of the loss sustained by the Institution, by themselves, and hy the wliole scientific world, in the decease of their friend and colleague, Dr. Warren de la Eue, who had been a valuable Member of the Institution for nearly thirty-eight years. " Dr. Warren de la Rue's high position in regard to science is universally recognised. The fruits of his invaluable researches in the various departments of Practical Astronomy, Solar and Lunar Physics, Celestial Photography, Electricity, Chemistry, and Meteorology, are fully recorded in the ' Transactions ' of the Eoyal Society, the Eoyal Astronomical Society, the Chemical Society, the Academy of Sciences, Paris, and in many other Scientific Journals. "Dr. Warren de la Eue became a Member of the Eoyal Institution in 1851. Previous to his election he was much interested in the objects of the Institution, and zealously assisted Professor Faraday in his researches and lectures whenever an opportunity presented itself. He was first elected a Manager in 1856, and closely attended the meetings of his colleagues until the end of his life. In 1879 he became Honorary Secretary, and held that office till 1882. During his long connection with the Eoyal Institution he was specially interested in the affairs of the Laboratory, and was a liberal contributor to the Fund for the Promotion of Experimental Eesearch, first started in 1863. He also frequently presented valuable apparatus, and eagerly embraced every opportunity of munifi- cently contributing towards the supply of whatever was needed by the Professors. His discourse on ' The Phenomena of the Electric Discharge, with 14,000 Chloride of Silver Cells,' delivered at the Eoyal Institution on January 21, 1881, will be long remembered by those who had the good fortune to hear it and witness his hrilliant experiments. Besides the great pleasure he derived from the prosecution of his own researches, for which he received many well-merited Honours both at home and abroad. Dr. de la Eue was happy in liberally aiding the labours of his fellow-workers, and contributed invaluable services to the Eoyal Institution while discharging the duties of Honorary Secretary and Manager and Vice-President. His genial manner and unvaried courtesy endeared him to all with whom he was personally connected, and his kindly presence will lonj^ be missed. 466 General Monthlij Meeting. [May 6, " The Managers further desire to be permitted to offer to Mrs. de la Rue and her family the expression of their most sincere sympathy with them in their bereavement." Besolved, "That the Honorary Secretary be requested to communicate this Resolution to the family." The Honorary Secretary was requested to convey the grateful thanks of the Members to Mrs. de la Rue for the generous spirit which prompted her to present the philosophical apparatus of the late Dr. Warren de la Rue, F.R.S. to the Royal Institution, and to inform her that this valuable gift will be carefully preserved as the historical collection commemorative of the important scientific work of Dr. Warren de la Rue, and of the eminent position which he has so long occupied as a promoter of Science, and of the special objects of the Royal Institution. The Special Thanks of the Members were given to Mr. John Young for his valuable gift of a portrait of Sir Humphry Davy, presented by him in the name of his son, Mr. James Young, grandson of the late Dr. James Young, F.R.S. of Kelly, the distinguished chemist and former owner of the portrait, and the Honorary Secretary was requested to inform Mr. John Young that the Members have groat satisfaction in receiving such a valuable addition to the collec- tion of historic portraits in the Royal Institution, and that they are gratified in the presentation being associated with the name of the family of the late Dr. Young. John Tyndall, Esq. D.C.L. LL.D. F.R.S. was elected Honorary Professor of Natural Philosophy. The Right lion. Lord Rayleigh, M.A. D.C.L. LL.D. F.R.S. was elected Professor of Natural Philosophy. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz : — FROM The Governor-General of India — Geological Survey of India : Records, Vol. XXII. Part 1. 4to. 1889. Accademia dei Lincti, Heale, Roma — Atti, Serie Quarta : Rendiconti. 1° Semes- tie, Vol. IV. Fasc. 11, 12 ; Vol. V. Fa.sc. 1, 2, 3. 8vo. 1889. Astronomical Society, lioijal— 'Monthly Notices, Vol. XLIX. No. 5. 8vo. 1889. Bankers, Institute of — lourual, Vol. X. Part 4. 8vo. 1889. Bavarian ^eatZem?/" o/" -Sc/ewces— Sitzungsberichte, 1888, Heft 3; 1889, Heft 1, 2. 8vo. 1889. Bernays, Albert J. Esq. Ph.D. F.C.S. M.R.I, (the Author)— "Sotea on Analytical Chemistry. Boston Society of Natural Histonj— Proceedings, Vol. XXHI. Parts 3 and 4. Svo. 1888. British Museum (Natural History)— Cdta\ogue of Fossil Fishes, Part 1. Svo. 1889 Catalogue of Fossil Cephalopoda, Part 1. Svo. 1888. Catalogue of Marsupialia and Monotremata, Svo. 1888. Catalogue of the Chelouians, Rhyuchocephaliaiis, and Crocodiles. Svo. 1889. 1889.] General Monthly 3Ieeting. 467 Cambridge Philosophical Society — Proceedings, Vol. VI. Part 5. 8vo. 1889. Chemical Industry, Society of — Journal, Vol. VIII. No. 3. 8vo. 1889. Chemical Society — Journal for April, 1889. 8vo. Cracovie, U Academic des Sciences — Bulletin, 1889. 8vo. Editors — American Journal of Science for April, 1889. 8vo. Analyst for April, 1889. 8vo. Athenaeum for April, 1889. 4to. Cliemical News for April, 1889. 4to. Chemist and Druggist lor April, 1 889. 8vo. Electrical Engineer for April, 1889. fol. Engineer for April, 1889. fol. Engineering for April, 1889. fol. Horulogical Journal for April, 1889. 8vo. Industries for April, 1889. fol. Iron for April, 1889. 4to. Murray's Magazine for April, 1889. Svo. Nature for April, 1889. 4to. Photographic News for April, 1889. 8vo. Revue Scientiiique for April, 1889. 4to. Telegraphic Journal for April, 1889. 8vo. Zoophilist for April, 1889. 4to. FranJdin Institute— J ouvnsil, No. 7G0. Svo. 1889. Hohnes-Forbes, A. W. Esq. M.A. M.B.I, (the Author) — Know Thyself; or Psychology for the People. 8vo. 1889. lou-a Laboratories of Natural History — Bulletin, Vol. I. No 1. 8vo. 1888. Latzina, M. F. (the Compiler) — Censo General de la Cuidad de Buenos Aires, 1887. 8vo. 1889. Marvin, Charles, Esq. (the Author)— The Coming Oil Age. Svo. 1889. Meriden Scientific Association — Transactii)ns, Au^)l. III. Svo. 1887-8. Meteoroloqical O^ce— Hourly Readings, 1886, Part 2. 4to. 1889. Quarterly Weather Reports, 1876, Part 4. 4to. 1889. Meteorological Society, Eoyal — Quarterly Journal, No. 69. Svo. 1889. Meteorological Record, No. 31. Svo. 1889. Ministry of Public Works, Rome — Giornale del Genio Civile, Serie Quinta Vol. III. Nos. 1, 2. Svo. And Disegni. fol. 1889. North of England Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVIII. Parts 1-2. Svo. 1889. Pharmaceutical Society of Great Britain — Journal for April, 1889. Svo. Physical Society of ioncZow— Proceedings, Vol. X. Part 1. Svo. 1889. Preussische Akademie der Wissenschaften — Sitzungsberichte, Nus. 38-52. Svo. 1888. Boyal College of Physicians, Edinburgh — Reports fi'om the Laboratory, Vol. I. Svo. 1889. Royal Society of London — Proceedings, No. 277. Svo. 1889. Saxon Society of Sciences, Boyal — Mathematisch-physische Classe : Abhandlung. Band XV. Nos. 3. 4. Svo. 1889. Skinner, W. B. Esq. (the Editor)— The Mining Manual for 1888. Svo. Society of Arcliitects — Proceedings, Vol. I. Nos. 9, 10. Svo. 1889. Society of Arts — Journal for April, 1889. Svo. St. Gallen, Geographisch Commerciellen Gesellschaft — Mitteilungen, 1889, Heft I. Svo. Stcdistical Society — Journal, Vol. LII. Part 1. Svo. 1889. Index to Vols. XXVI.-L. (1873-87). Svo. Telegraph Engineers, Society o/— Journal, No. 78. Svo, 1889. Vereins zur Beforderung des Geicerbjieisses in Heft IV. 4to. Zoological Society — Transactions, Vol. XII. Part S. 4to. 1889. Proceedings, 1888, Part 4. Svo. 1889. 468 Professor Dewar [May 10, WEEKLY EVENING MEETING, Friday, May 10, 1889. William Crookes, Esq. F.R.S. Vice-President, in the Chair. Professor Dewar, MA. r.R.S. M.B.I. Optical Properties of Oxygen and Ozone, In the course of experiments on the spectra of gases at high pressures, Professor Liveing and I have made observations on the absorption- spectrum of oxygen which confirm and extend the observations of Egoroff and Jansen. The interest of this spectrum is so great, on account of the important part which oxygen plays in our world, and its free condition in our atmosphere, that it deserves a separate notice. In order to include the ultra-violet rays in our observations we have had to contrive windows of quartz to the apparatus containing the gases. A strong steel tube, 1G5 centimetres long and 5 centi- metres wide, was fitted with gun-metal ends, bearing by curved Fig. 1. Section through one end of the tube. surfaces upon the conical openings of the tube, and forced home by powerful screw-caps. Each gun-metal end was pierced centrally by a conical opening fitted with a quartz stopper, 2*1 centimetres thick, and of the same diameter, with plane polished ends. A small amount of wax was interposed between the stopper and the gun-metal for the purpose of ensuring a uniform bearing for the quartz, which is very brittle. Trial proved that the tube thus fitted would sustain, without leakage, a pressure of upwards of 260 atmospheres. The tube had, besides, near each end, a screw-j^lug valve for admitting the gases. About the centre of the tube was placed a quartz lens, rather less in diameter than the tube, held in place by three sinings which pressed against the walls of the tube. This lens had a focal length of about 46 centimetres ; so that when a source of light was 1889.] on Optical Properties of Oxygen and Ozone, 4G9 placed about 10 centimetres from one end of the tube, an image of it was formed on the slit of the spectroscope at about the same distance from the other end of the tube, and thereby loss of light, so far as it was due to the distance of the source, was reduced to a minimum. Ordinary oxygen was let into the tube from an iron bottle until the pressure reached 85 atmos2>heres, and on viewing an arc light through the tube the following absorptions were visible : — (1) A very dark band sharply defined on its more refrangible side, gradually fading out on its less refrangible side, and divided into two parts by a streak of light, occupying the jjosition of A of the solar spectrum. (2) A much weaker, but precisely similar band in the position of B of the solar spectrum. (3) A dark band very diffuse on both edges, extending from about X 6360 to X 6225, with a maximum intensity at about A. 6305. (4) A still darker band a little above D. beginning with a diffuse edge at about A. 5810, rapidly coming to a maximum intensity at about A. 5785, and then gradually fading on the more refrangible side, and disappearing at about X 5675. (5) A faint narrow band in the green at about A. 5350. (6) A strong band in the blue, diffuse on both sides, extending from about X 4795 to A 4750. When photographs were taken of the ultra-violet part of the sj^ectrum of the arc and of the iron spark, the gas appeared to be quite transparent for violet and ultra-violet rays up to about X 2745. From that point the light gradually diminished, and beyond X 2664 appeared to be wholly absorbed. The pressure of the oxygen in the tube was then increased to 140 atmospheres. This had the effect of increasing sensibly the darkness of all the bands above described ; but brought out no new bands, excej)t a faint band in the indigo at about X 4470. In the ultra- violet the absorption appeared to be complete for all rays beyond about X 2704. The foregoing observations were made with a spectroscope of small dispersion. We next brought to bear on the spectrum a large instrument with one of Eowland's gratings. Even with the high dispersion of this instrument, the bands at A could not be resolved into lines; they remained two diffuse bands; though the red potassium-lines, which were produced by sprinkling the electrode of the arc with a potassium-salt, were sharply defined and widely separated. None of the other bands were resolvable into lines. This we attribute to the density of the gas, by which the lines are expanded so as to obliterate the interspaces ; and this supposition is confirmed by the observation of Angstrom, that the band in the solar spectrum which appears to be identical with that observed by us a little above D, was resolved into fine lines when the sun was high, but appeared as a continuous band when the sun was near the horizon. 470 Professor Dewar [May 10, On letting down the pressure the bands were all weakened; A, though weaker, became more sharply defined at the more refrangible edge. The faint band in the iudifjo A 4470 remained just visible until the pressure fell below 110 atmospheres. At 90 atmospheres A and B were still well seen and sharp, but all the other bands weaker. B remained visible until the pressure fell to 40 atmosplieres. A was then still well seen, the band just above D very faint, and the others almost gone. At 30 atmospheres A was still easily seen, and there was a trace of the band above D. At 25 atmospheres this band had gone, but A remained visible until the j^ressure fell to less than 20 atmospheres. Hence an amount of oxygen not greater tlian that contained in a column of air 150 metres long at ordinary pressure, is sufficicDt to produce a visible absorj^tion at A. The quantity of oxygen in the tube at the highest ])ressure we used falls, however, far short of the quantity traversed by the solar rays in passing through the atmosphere when the sun is vertical. It will be noted that the bauds, if we except the faint two in the green and indigo respectively, aj^pear to be ^identical with those terrestrial bands in the solar spectrum which Angstrom found to be as strong when the air was dried by intense frost as at otlier times. At least the positions of the maxima agree closely, and that near D shows the same j^cculiarity in having its maximum near the less refrangible end. We did not, however, observe a, which would be fainter than B, and if, like A and B, unresolvable, would be lost iu the diffuse band which covers that region. The bands above numbered 3, 4, 5, 6, agree also with those observed by Olszewski,* to be produced by a layer of liquid oxygen 12 millimetres thick. The point also at which the absorption of the ultra-violet rays begins, agrees with that at which the absorption by ozone begins, as observed by Hartley | ; but the oxygen, as we used it, did not appear to transmit the more refrangible rays beyond 2320, which seem to pass through ozone. Egoroff j found that A remained visible when he looked through 80 metres of atmosphere, but 3 kilogrammes of atmosphere failed to produce a. When the pressure in our tube was reduced , a cloud was always formed which rendered the contents of the tube nearly opaque ; the faint light which was then transmitted had always a green tinge. It is remarkable that the compounds of oxygen do not show any similar absorptions. Angstrom thought it improbable that oxygen should have a spectrum of such a character, since he failed to obtain an emission spectrum resembling it ; and suggested that the absorptions might be due to carbonic acid gas or to ozone, or possibly to oxygen in the state in which it becomes fluorescent.§ Neither carbonic acid gas nor nitrous oxide, at a pressure of 50 atmospheres in our tube, show any sensible absorption in the visible spectrum; * Wied. *Ann.,' xxxiii. p. 570. f ' Jouin. Chem. Soc..' xxxix. p. 57. X 'Coraptea Rendu.s,' ci. p. 1144. § 'Spect. Norm.,' p. 41. 1889. 1 on Optical Properties of Oxygen and Ozone. 471 and tlie absorj^tion of the ultra-violet rays by the latter gas begins at a higher point, namely about X 2450, than that of uncombined oxygen. In fact, we see the anomalies of the selective absorjition by compounds as comjDared with that of their elements when we take the case of water, which has a remarkable transparency for those ultra- violet rays for which oxygen is opaque. These observations show that all stellar spectra observed in our atmosphere, irrespective of the specific ultra-violet radiation of each star, must be limited to wave-lengths not less than X 2700, unless we can devise means to eliminate the atmospheric absorption by observa- ,tions at exceedingly high altitudes. We have extended our observations to much longer columns of ^oxygen. A steel tube 18 metres long (see Fig. 2) w^as fitted with the same quartz ends as had been used with the shorter tube, and with two quartz lenses symmetrically j)laced inside the tube, one near Fig. 2. I ^miA Jni LENS LENS jc . ''S^Mn.m nrziz^^ Section of Steel Tube. each end, so that when an arc lamp was placed about 14 centimetres from one end of the tube, the image of it was formed on the slit of the spectroscope at the same distance from the other end. When the tube was tilled with air only at ordinary pressure, no absorptions could be detected, but when the air was replaced by oxygen at the pressure of the atmosphere the absorption of A was just visible, though neither B nor any other absorption-band could be traced. As the pressure of the oxygen was increased, A became much darker and more distinct, and B came out sharply defined. The absorption-band about A 5785 was next seen, and the dark bands about X 6300 and X 4770, were just visible when the pressure reached 20 atmospheres. At a pressure of 30 atmospheres A was very black, B also strong and sharply defined, and the forementioned bands were all quite strong and had the same general characters as when seen through the shorter tube ; the band about X 6350 also could be seen, but there was only a bare trace of that in the indigo about X 4470. At 60 atmospheres these last two absor23tions could be well seen, all the other bands were very sti ong, B still quite sharp, but A somewhat obscured by a general absorption at the red end. At 90 atmospheres this general absorption at the red end seemed to extend to about one- third of the distance between A and B ; but A could still be seen, w^hen the slit was wide, as a still darker band on a dark red back- ground ; B was still sharp, and the other absorptions all strengthened 472 Professor Dewar [May 10, 1889.] on Optical Properties of Oxygen and Ozone. 473 and somewhat expanded. The diffuse edges of several bands now extende Ifrom about — ( I) X 6410 to 6190, (2) A 5865 to 5635, (3) X 5350 to 5280, (4) A 4820 to 4710, A 4480 to 4455. Photographs taken when the pressure of the oxygen was 90 atmo- spheres show a faiut absorption-band about L of the solar spectrum, a stronger band extending from about A 3600 to 3640, a broad diffuse band about the place of the solar line 0, and complete absorption abova P. The accompanyini^ diagram, Fig. 3, represents the ab- sorption of 18 metres of ordinary oxygen at a pressure of about 97 atmospheres. The absorbent column in the tube at the highest pressure used con- tained a mass of oxygen about equal to that in a vertical column of the earth's atmosphere of the same section as the tube ; but the intensity of the bands produced by the compressed gas was far greater than that of the corresponding bands in the solar spectrum with a low sun. When the arc light was replaced by a piece of white paper reflecting light from the sky through the tube, it appeared to the naked eye to have a faint blue tint, similar to that of liquid oxygen, which, com- paring our observation with Olszewski's, seems to have the same absorptive powers as the dense gas, if we except A. This exception is probably only apparent, and due to the difficulty of observing A under the circumstances of Olszewski's experiment. The greatly increased intensity of the absorption-bands at high pressures bears out Jansen's observation, that in this group the absorption is proportional to the product of the thickness of the absorbent stratum into the square of its density, while the absorptions to which A and B belong vary directly as the density. The appearance, on looking through the tube when gas at high pressure is streaming into it, is very much like that of a black and a colourless liquid, which do not mix, being stirred together, and the tube soon ceases to transmit any light. Transparency returns as the dens'ty becomes uniform. Currents produced by heating the tube at one or two points produce a similar effect, and show that such currents in the atmosphere of a star may stoj) all rays coming from its interior. We hope bef )re long to get the tube fitted with rock-salt ends and lenses, and to determine the total absorption of radiation by similar masses of oxygen, nitrogen, and hydrogen. [J. D] 474: Professor Silvanas P. Thompson [May 17, WEEKLY EVENING MEETING, Friday, May 17, 1889. John Rae, M.D. LL.D. F.R.S. Vice-President, in the Chair. Professor Silyaxus P. Thompson, B.A. D.Sc. 3LB.I. Optical Torque.* Seventy-eight years have elapsed since the first discovery, by Arago, of the remarkable chromatic effects produced by slices of quartz crystals upon light, previously polarised, which was caused to traverse them. These effects were shown, one year later, by Biot, to be caused by a peculiar action of the quartz in rotating the plane of polarisation ; the amount of the rotation being different for lights of different colours. Ever since then, the rotation of the j^lane of polarisation of light has been a topic familiar to physicists. It has stimulated the devotee of research to an endless variety of experiments and sug- gestive speculations : it has lured on the mathematician to problems which tax his utmost skill : it has afforded to the lecturer an array of beautiful and striking illustrations. Here, in this place, made classical by the researches and expositions of Thomas Young, of Michael Faraday, and of William Spottiswoode, and last, but not least, by the labours of those eminent men whom we rejoice still to number amongst the living — here, I say, on this classic ground, the rotation of the plane of polarisation of light is almost a household word, and its phenomena are amongst the most familiar. We know now that not only certain actual crystals, such as quartz, bromate of soda, and cinnabar, rotate the plane of polarisation, but that many non-crystalline bodies — liquids, such as turj^entine, oil of lemons, solutions of sugar and of various alkaloids, and even certain vapours, such as that of camphor — possess the same property. In 1845, at the very culminating point of his unique career of research, Faraday opened a new field of inquiry, linking together for the first time the science of optics with that of magnetism, by his discovery that the rotation of the plane of polarisation of light could be effected by the application of magnetic forces. This effect he observed first in his peculiar " heavy-glass," when it lay in a powerful magnetic field. Subsequently he found other bodies to possess similar properties : some of these being magnetic liquids, such as solutions of iron, others being diamagnetic. Time will only permit me in passing to refer to the researches of Verdet, and those of Lord Rayleigh and of Mr. Gordon upon the numerical values of the * The blocks of the woodcuts illustrating this discourse have been kindly lent by the publishers of Nature. 1889.] on Optical Torque. 475 magneto-optic rotation in these substances. H. Becquerel has ex- tended them to gases, and has shown how the magnetism of the earth rotates the plane of j)ohirisation of the light which, previously j)^*l^i'" ised by reflection from the aerial particles which give the sky its blue tint, passes earthward through the oxygen of the air. Other experimenters have dealt with the rotatory effects (whether crystalline, molecular, or magnetic) in relation to lights of different colours, and have studied the dispersion which arises from the greater actual angle of optical torsion which is produced ujDon weaves of short wave-length (violet and blue) than that which is })roduced under the influence of equal rotatory forces upon the waves of longer wave-length (red and orange). It has also been demonstrated that the plane of polarisation of waves of invisible light, whether those of the infra-red, or those of the ultra-violet species, if they have been previously polarised, can be rotated just as can that of waves of visible light. In 1877, Dr. Kerr, of Glasgow, discovered a point w'hich Faraday had sought for, but fruitlessly — namely, that in the act of reflection at the pole or surface of a magnet, there is a rotation of the plane of polarisation of light. This discovery was completed in 1884 by Kundt, of Strasburg, by the further demonstration, also dimly fore- seen by Faraday, that a magneto-optic rotation of the plane of polari- sation is caused by the passage of previously polarised light through a normally magnetised film of iron so thin as to be transparent. Lastly, in this brief enumeration, we were shown a month ago, by Oliver Lodge, how the magnetic impulses generated by the raj^id oscillatory discharges of the Leydeu jar can produce corresponding raj)id oscillatory rotation in the plane of polarisation of the waves of previously polarised light. You will not have failed to notice the cumbrous j^hrase which, whether in speaking of the purely optical effects (of quartz, or sugar, or turpentine), or in speaking of the magneto-optic effects of more recent discovery, I have employed to connote a very simple fact. You may have wondered that any lover of simple English speech should indulge in such sesquipedalian words. Of course, at this period of the nineteenth century it is no longer open to debate that light consists of waves. The plaue of polarisation of the waves of light is the plaue of polarisation of the light itself. The rotation of the plane of polarisation is the rotation of the polar- ised waves, and therefore of the polarised light itself. Yet 1 must draw attention to the fact that in all the array of discoveries which I have enumerated, that which had been observed was the rotation — whether by crystalline, molecular, or magnetic means — not of natural light, but of light which had by some means been previously polarised. It was not known to Arago or to Biot, to Fresnel, to Faraday, nor even to Spottiswoode or to Maxwell, that natural impolarised light could be rotated. They may have inferred so, but it was not in their time even demonstrable that a beam of circularly- YoL. XII. (No. 83.) 2 K I 476 Professor Silvaniis P. Tliomjpson [May 17, polarised light could be rotated upon itself in the same sense as that in which a beam of plane-polarised light can be rotated. That light of any and every kind, however completely polarised or devoid of that which is called polarisation, can be, and in fact is, rotated when it passes across a slice of quartz or along a magnetic field, is a wider generalisation of more recent date ; but one of the reality of which I hope to convince you before the warning finger of the clock puts a period to my discoiu'se. In order the better to enable this audience to comprehend the ultimate significance of this discovery, I must claim the indulgence of those amongst them who are already familiar with the subject of the polarisation of light, whilst I go back to the most simple ele- mentary matters. Having illustrated the fundamental facts about the plane of polarisation of light and its twisting, I shall then go on to methods of precisely measuring the amount of optical torsion pro- duced by the various substances under various conditions. And after dealing with the magnetic as well as the crystalline and molecular methods of producing optical torsion in the case of light that has been previously polarised into a given plane, I shall be in a position to speak of the nature of the torque,* or twisting force, which in the several cases produces the torsion ; and shall finally endeavour to indicate the scope of the researches by which it is now definitely ascertained that the very same optical forces which are capable of impressing a rotation upon light which has been artificially polarised into a definite plane, are also ca2)able of impressing a rotation ujjon natural non-polarised light. At the outset, to elucidate to any who may not comprehend the meaniug of the term polarisation as aj^plied to wave-motion, I will show a simple apj)aratus, constructed from my designs by Mr, Groves. In this there are two sets of movable beads, fixed upon stems which pass into a box containing a piece of mechanism actuated by means of a handle. These beads, when I turn the handle, oscillate to and fro in definite directions, and, by their successive motions, give rise to progressive waves. One set of beads, tinted red, executes move- ments in a plane inclined 45^ to the right, another set, silvered, simultaneously executes movements at 45"^ to the left. There are therefore here two waves, the planes of polarisation of their move- ments being at right angles to one another. Their velocity of march is equal ; but in this model, as a matter of fact, their phases difier by one-quarter — that is to say, each successive wave of the one set is always a quarter of a wave-length behind the corresponding wave of the other set. [Model exhibited.] * The convenient term Torque was first proposed by Prof. James Thomson, of Glasgow, for the older and more cumbrous phrase " moment of coupk^," or " angular force." Its general acceptance by engineers justifies the extension of the term to optics. As a mechanical torque is that which produces or tends to produce mechanical torsion, so optical torque may be defined as that which produces or tends to produce optical torsion. 1889.J on Optical Torque. 477 Now, in the case of waves of natural light from all ordinary sources— sun, stars, candles, gas-flames, or electric lights — the waves emitted are not found to be polarised. That is to say, their motions are not executed in any particular plane, nor even in any particular path of any kind ; they appear to be absolutely heterogeneous at least so far as this, that no vibration of the millions of millions emitted in a second of time is followed by more (on the average) than about 50,000 vibrations of a similar sort, executed along a similar j^ath — the plane of the polari- sation, if any, changing after the lapse of such an incredibly short time that for most purposes the vibrations in ditferent directions are as inextricably mixed as if they had all been simultaneously jumbled up. Since, then, natural light is non-polarised or miscellaneous, the pro- duction of polarised light must be brought about by the employment of polarising apparatus or agents which will so operate on or affect the mixed waves as to bring their vibrations into one direction — or, what amounts to the same thing, transmit the light whilst destroying or absorbing those parts of the vibrations which are executed across the desired line of vibration. So we have jjolarisers consisting of tour- maline slices ; oblique bundles of thin glass plates ; black - glass reflectors ; and Nicol prisms cut from calc-spar. About the two latter I may be permitted a passing word presently. These objects polarise, i.e. tiu-n into one plane, the vibrations of light falling upon them. A rough mechanical illustration may here be permitted me. A long indiarubber cord is passed through the open ends of a box provided with vertical partitions. Fig. 1 shows the arrangement. These partitions confine the motion of the cord, and effectually polarise the vibrations which I now impart to the cord by shaking the end of it to and fro. If the partitions are vertical, the box polarises, into vertical vibrations only, the miscellaneous vibrations which are sent to it. If rotated until its partitions ai-e horizontal, it polarises the vibrations into a horizontal position. Let us now turn to the optical analogue of this experiment. The large Nicol prism which I introduce into the field of the electric- light lantern, polarises the light, so that the vibrations are executed dimply in an up-and-down direction. Your eye will not detect this, he motion being millions of times too rapid. To detect the direction m analyser is necessary. For this purpose a second apparatus of he same sort is used, for then, by crossing the positions of the two, ho whole of the light is cut off"; the second Nicol prism, if set so as o transmit only horizontal vibrations, cutting off the vertical dbrations that are sent through the first prism. So, while the first )rism serves as a polariser, the second serves as an analyser to detect )y cutting them off when turned to the proper position, the direction •f the polarisation which had been previously impressed by the first -rism. Here I may illustrate the action of the analyser for determininc^ he plane of polarisation of the vibrations by the extinction which it reduces when turned to the crossed position. For this i^urpose I 2 K 2 478 Professor Silvanus P. Thornjjson [May 17, CQ 1889.] on Optical Torque. 479 -o-^ '480 Professor Silvamis P. TJiompson [May 17, have refined upon the box with partitions, using instead parallel plates of glass mounted in wooden cylinders, whilst for tlie cord swung by hand I am using Professor Schwedoff's device, and am producing the vibrations in this silken cord by means of an electri- cally-driven tuning-fork (Fig. 2). At tlie first nodal point of the stretched cord a pair of parallel glass plates act as a polariser, the cord beyond that jDoint vibrating in the plane thus imposed upon it. I can alter this plane at will by rotating the polariser. This polariser, P, consisting of a pair of glass plates, is mounted in a cylindrical mount, and is provided with an arrow to indicate their direction. If now at any subseii[uent node I introduce a second such device, it will act as an analyser, A. This excellent suggestion is due to M. Mace de Lepinay. In Fig. 2 the jiolariser and analyser are parallel. You see (Fig. 3) how the vibration is extinguished when the positions of analyser and polariser are crossed. Half a degree of error in the position of the analyser produces something less than perfect extinc- tion of the vibrations. Hence it is possible, by this analyser, to determine the plane of the vibrations to the accuracy of half a degree. I should say that the whole of this model has been con- structed by my assistant Mr. Eustace Thomas. Now let me show you the optical effect which corresponds to this. Placing a second Nicol prism as analyser in the path of the polarised waves, I turn it to the position where it cuts off the polarised light. The ^^ dark field" so produced by the crossed Nicol prisms corresponds to the motionless cord beyond the crossed analyser of the acoustic apjiaratus. Keturning for a moment to two well-known forms of polarising apparatus, viz. the black glass reflector and the Nicol prism, I may be permitted to refer to some recent attempts to improve ujion these devices. The Nicol prism, as is well known, consists of a rhomb of Iceland spar cut into two pieces, which are reunited by a film of Canada balsam. As originally devised, Fig. 4. it had oblique end faces (Fig. 4) and a comparatively narrow angle (19°) of aperture. These may be noticed in the small example which I here exhibit, which is an original constructed by William Nicol himself. It also has the disad- vantage of giving a field in which the -If directions of the planes of polarisation aZJshZscryZZgrZhic'''^^ ^^^ «t^i«% V^^^^^^^ to one another axis. throughout its whole extent. Consequently there is never complete extinction of light all over the field at one time. Hartnack and others have attempted to remedy this by giving the prism a different form and using other materials than Canada balsam. I have from time to time made many attempts to improve upon the original construction. 1889.' on Optical Torque. 481 First, I have made the end faces principal planes of section (Fig. 5) ; secondly I have made the axis of vision cross the crystallograjDhic axis at right angles, so getting a flatter field, a shorter length, a wider angle, and less loss of light by reflection. Mr. Ahrens, the prism-cutter, on whose able assistance I have relied during the last six or seven years in cutting these prisms, has aided me with his ingenuity in devising a method of cutting up the spar so as to give these advantages with a minimum waste of material. He has farther devised a method of putting a polarising prism together in three Fig. .5. Fig. 6. S. P. Thompson's modification of the Nicol prism. Ahvens's triple prism. instead of two pieces — illustrated in the diagram (Fig. 6) — which gives a still wider angle. The prism which I shall use as analyser in the next ex|)eriments is one of these forms. Unfortunately at present there is a spar-famine, pieces of Iceland spar of a size and purity suitable for the making of large polarisers such as that I employ being not now procurable at any price. To avoid the excessive cost of large Nicols I have lately got Mr. Ahrens fco construct for me a large reflection-polariser, on the plan of Delezenne, but modified by Mr. Ahrens in detail. In this prism the light is first turned to the proper polarising angle by a large total- •eflection prism of glass, and then reflected back, parallel to its )riginal path, by impinging upon a mirror of black glass covered by I single sheet of the thinnest patent plate glass to increase the ntensity of the light. This form of polariser, depicted in Fig. 7, is [uite equal for projection purposes to a Nicol prism of equal aperture, Lud is much less costly. This one has 2| inches clear aj^erture. Having so far reviewed the apparatus for polarising and analysing '. will return to the apparatus set with its prisms crossed, so that the nalyser completely extinguishes the polarised light emitted from the •olariser. If in the space between polariser and analyser anything be intro- uced which can either resolve obliquely the polarised vibrations or vist them bodily round, then there will not be complete extinction ; le amount of light passing the analyser depending in the one case Q the obliquity of the resolution, in the other upon the degree to hich the vibrations are twisted or rotated upon themselves. 482 Professor Silvanus P. Thompson [May 17, The effect of oblique resolution I may illustrate by introducing a slice of tourmaline between the crossed Nicols, and rotating it till it stands at 45^ ; or, in the acoustic model, by introducing an oblique pair of guide pins. The other case — namely, that of producing a bodily twist of the vibrations, rotating the plane of polarisation around the path of tlie wave — is not so easily illustrated by the model. But it is optically perfectly simple : all that is requisite is to introduce between the Fig. Ahrens's reflecting polariser. crossed Nicols a thin slice of that crystal — namely, quartz — in which this effect of rotating the plane of polarisation was first observed. I take a clear plate of quartz, just 1 millimetre in thickness, and interpose it between the crossed Nicol prisms. You will note how the introduction of this plate of quartz brings some light into view. Suppose we now turn the analyser to try and obtain extinction : we get tinting. If we put in a coloured glass so as to work with one kind of light only, we shall get extinction at a particular angle. The 1889.] on Optical Torque. 483 table of data to whicli I invite your attention states this amount for the different colours. Optical Torsion Produced by Plate of Quartz. 1 millimetre. 3-75 millimetres. Ked .. 19 .. o 71-2 Orange 21-5 .. 80-6 Yellow 24 90 Green 29 108-7 Peacock 31 116-2 Blue .. H5-5 .. 133-1 Violet .. 42-8 .. 161 If we use a piece of quartz so thick that it rotates any particular tint just 90^, that tint will be cut off by the crossed analyser, and all others will — in greater or less proportion be transmitted, so that the resulting tint will be complementary to that cut off. For example, a slice so thick as to twist yellow waves round 90° must be just 3*75 millimetres thick. (I may remark, for the benefit of those who think it easier to express this exact thickness in fractions of a British inch, that the quartz which rotates yellow light 90° must have a thickness equal to one-ei»hth, plus three-sixteenths of an eighth, plus one sixty-fourth of an eighth of an inch.) When such a quartz is placed between the crossed Nicols the light shown is yellow ; but if placed Between parallel Nicols (i. e. in the bright field) it shows a rich j)urplish-violet colour, the comple- mentary of the yellow. This particular tint Biot found to be excessively sensitive, the smallest inaccuracy in adjustment between the prisms at once producing a change, the colour appearing too red or too blue, according to the directions in which the analyser has been turned out of exact adjustment. This tint is accordingly known as the " transition tint " or " sensitive tint," its accurate definition being due to the fact that the human eye is more sensitive to the presence or absence of the complementary yellow than to any other tint in the whole spectrum. If we take, however, a quartz plate twice as thick as this — namely, 7J millimetres thick — it will give the yellow light a torsion of 180°. Hence this thickness gives the purple transition tint in the dark field, and yellow in the bright field. A quartz plate 11^ millimetres thick gives again a transition tint in the bright field. I shall recur presently to the question of the transition tints of the several orders. One of the familiar facts in this subject is that there are two kinds of quartz crystals, optically alike in every other respect, differinf^ only in this, that one kind produces a right-handed twist, the other kind a left-handed twist. All the pieces of quartz I have so far em- ployed are right-handed specimens. I now introduce two small slices of crystal, each 3 -75 millimetres thick, giving the yellow tint when the Nicols are exactly crossed, but you will notice that when we are using the right-handed crystal, the tint grows reddish as the 484 Professor Silvanus P. Thompson [May 17, Fig. S. analyser is turned towards the left, and greenish when the analyser is turned towards the right ; whereas, when I substitute the left- handed slice, the tint grows greenish as the analyser is turned towards the left, and reddish when it is turned towards the right. If the analyser is turned through an exact right-angle, we get an extinction of the yellow light, the remaining blue and red rays combining to give us the purple transition tint. You will have noticed that the way in which we have (approxi- mately) measured the angle of rotation has been first to set the analyser to extinction, then to introduce the substance which has the property of rotating the beam, then to turn the analyser again to ex- tinction, and read off its angle. For, of course, the angle through which the analyser is turned measures the angle through which the plane of polarisation has been turned. It is possible, however, to show in the lantern something like a more obvious rotation of the light by introducing between the Kicols a crystal star, built up of radial pieces of mica, twenty-four in number (Fig. 8). You see in the bright Held a white cross with black sectors at 45'. Or, in the dark field we have a black cross with vertical and horizontal arms, the sectors next to those that are black seeming dusky. If now I put in a quartz plate between the star and the analyser, you see the cross shift round, and it shows colours, because the rays are twisted round more the green, the green than yellow, the yellow than the Repeating the experiment the 3 "75 millimetre quartz which turns yellow waves round just 90', we get this gorgeous radiation of colours, and our black cross is turned into a yellow one. With the 7 • 5 millimetre quartz, the black cross is replaced by one of " transition " tint. The black crosses seen in certain sections of natural crystals, sphseroliths, sections of stalactites, crystallisations of salicine and of Epsom salts, may also be used instead of the 24-rayed star of mica. But best of all I find to be the beautiful black cross which is seen by polarised light in the prepared crystalline lens taken from the eye of a fish. You notice how, when the fish-lens is projected and the quartz introduced, the cross turns round. This is, however, a rough-and-ready way of displaying the rotation, and it is of vast practical importance that precise methods of measur- ing the angle of rotation should be available — of vast importance, blue than the red. with Mica disk of twenty-four rays, showing black cross in the dark field. 1889.] on Optical Torque. 485 because in several large industries this optical process is applied as a method of rapid analysis. I have named a solution of sugar as being an " active " substance. In the industry of sugar-refining, as in that of brewing, the strength of sugar in the liquids is dii-ectly measui'ed by measuring its optical effect. Consequently there has been deve- loped a special instrument, the polarimeter, for this express purpose. I have here examples of several practical forms of polarimeters ; there are diagrams of several more uj)on the walls. The problem of finding the best polarimeter naturally leads to the inquiry what special means there are for making the observation of the angle more precise than by merely observing the extinction of the light, its restoration when the active substance is interposed, and the subsequent renewal of extinction when the analysing prism is turned. Biot considered that much greater arujection of spectrum. its odour is a delicate reminiscence volatile ; and it is whiter than bisulphide. This prism, which is shown also in plan in Fig. 10, was constructed for me by Messrs. R. and J. Beck. It will be seen that the dark bands in the sj)ectrum are nebulous and ill-defined. It was proposed to secure accuracy by turning the analyser until they shift along to a definite point. But their want of definition prevents precision. There is no advan- tage in using the higher orders of tints which give more bands; for, though the bands are certainly better defined, their progression across the spectrum for a given amount of rotation is proportionally smaller. 1889.] on Optical Torque. 487 Another suggestion, due to Senarmont, is to use two sets of super- posed wedges of riglit- and left-handed quartz. Such you now see before you. Instead of starting with extinction you start with coinci- FiG. 10. ->-. Direct-vision prism. A, wide-angled prism of Jena glass ; C, cinnamic eth( -5-K V dence between the upper and lower set of bands. Any rotation of the light shifts the bands, one set moving to left, the other to right. By turning the analyser through an equal angle coincidence is again obtained. Another method, used by Wild in his polaristrobometer, is to produce the phenomenon known as SavaTt's bands (due to the intro- duction of two crossed slices of quartz cut at a particular angle). The bands disaj)pear when the analyser is set in a particular direction. Anything that twists the plane of polarisation causes them to reap- pear ; but they again fade out when the analyser is turned through an equal angle. There is another method in exact polarimetry, due to Soleil, in which the optical torsion due to the sugar is counterbalanced or compensated by introducing a pair of sliding wedges of quartz of the opposite rotation. This device is known as a "compensator." By sliding the quartzes over one another a greater or less thickness of quartz is introduced at will. But I must not stop to illustrate this elegant device. Yet one other method must be mentioned, and this is certainly the most preferable. It consists in aiding tlie eye to recognise with precision a particular degree of extinction, by the device, first suggested in 1856 by Pohl, of covering a portion of the visible field with some- thing which slightly alters the initial plane of polarisation, so that complete blackness is not obtained at once over both parts of the field. A common device is to cover half the field with a slice of some thin crystal — mica or quartz — so that only one half can be perfectly black at any instant. As an example, here is the field covered half over with a plate of mica of the thickness known as half-wave. The result is that when one half of the field is black the other is light. Adjust the analyser now to equality. Now introduce something that 488 Professor Silcanus P. lliompson [May 17, rotates the light — say a tube with sugar solution in it. At once the balance is upset, and I must, in order to get equality of illumi- nation, turn my analyser through an angle equal to that of the optical torsion. Of the same class are the polarimeters with special prisms made in two parts slightly inclined to one another. 1 he earliest of these was devised by the late Professor Jellett, of Dublin, and has been followed by imitations of the same plan by Cornu, by Lippich, and by Schmidt and Haensch. The beautiful " shadow polarimeter," by the latter firm, which I here exhibit, has the divided prism, and a quartz compensator. I have suggested two simpler methods of accomplishiug the same end. In the first place, I have proposed to use twin-prisms. These are made on a plan suggested to me by finding that Mr. Ahrens's method of cutting calc-spar for prisms was admirably adapted for making such prisms, either with wide or narrow angles between the respective j^lancs of polarisation in the two parts of the visible field. Two such twin-i)risms, one with 90°, the other with 2J°, between the prisms, are here on the table. In the second place, I have essayed a polarimeter, an example of which is before you, in which an arrange- ment of twin-mirrors (each set at the polarising angle, but slightly inclined to one another) is made to yield a half-shadow effect. Before I leave the subject of quartz I must refer to the famous mathematical theory of Fresnel, who endeavoured to explain its action Fig. 11. Model illustrating recomposition of rectilinear motion irom two opposite circular motions. upon light by supposing that the jDlane-polariscd wave on entering it is split into two waves, consisting of 02)positely circularly-polarised light, which traverse the crystal with different speeds. On emerging they recombine to form plane-polarised light, the jDlane of which, how- ever, depends on the retardation of phase between the two components. I here introduce a mechanical model to illustrate one of the points in this theory — namely, the recombination of two circular motions to form a straight-line motion. These two disks (Fig. 11), which turn in opposite senses, but at equal rates, rei^resent two circularly-polarised beams of light. The linkages, which connect two pins on these disks, compound their motions at the central point, P, which executes, as 1889.] on Optical Torque. 489 you see, a straight line. But now, suppose one of these circular motions to be retarded behind the other, an effect which I can imitate by shifting one of the pins to another position on the disk. Still the resultant motion is a straight line, but it is now executed in a direc- tion oblique to the former. In other words, its plane has been rotated. Of course this model must not be taken as establishing the truth of Fresnel's ingenious theory ; it is at best a rough kinematical represen- tation of it. We have, however, the puzzling fact still to account for that there should be two kinds of quartz crystals, right- and left-handed. Sir John Herschel first showed that natural crystals of quartz themselves often indicated their optical nature, by the presence of certain little secondary faces or facets which lay obliquely across the corners of the primary faces. These are indicated in the diagrams (Figs. 12 and 13), and may be seen in two of the specimens of quartz crystals Quartz crystal, showing characteristic facets : ri^ht-handed. Quartz crystal, showing characteristic facets : left-handed. which lie upon the table. The largest of these is right-handed. The wider generalisations of Pasteur, respecting the crystalline form of optically active substances, show that those substances which exercise an optical torque, whether as crystals or in solution, belong to the class of forms which the crystallographer distinguishes as i^ossessino- Qon-superposable hemihedry. In other words, they all show sJceio 'symmetry, as if in the growth of them they had been built uj) in some screw-fashion around an axis, and must therefore be either right- handed or left-handed screws. By piling up a number of wooden slabs in skew-symmetric fashion, I am able roughly to illustrate ^Figs. 14 and 15) the difference between the right-handed and the left-handed structure. It is a curious fact, if I am rightly informed, :hat down to the present date the only substances possessing this skew symmetry are natural substances ; that those which the chemist can Droduce by artificial synthesis are all optically inactive. It is per- I 490 Professor Silvanus P. Thompson [May 17, haps equally significant that as yet no inorganic substances have been found which will in the liquid state rotate the light. This appears to be a property possessed solely by certain compounds of carbon. Fig. 14. Fig. ir>. Skew-symmeti-ical arrangement ; ricrht-handed. Skew-symmetrical arrangement ; left-handed. Quartz fused in the blowpipe or dissolved in potash shows no trace of rotatory power. Yet we can have little doubt that this property is bound up in the yet unravelled facts of atomic and molecular structure. In the case of the liquids, such as turpentine, and sugar solution, there must be some skew symmetry in the grouping of atoms in the molecule to produce the result. In the case of quartz, there must be a skew in the building of the molecules ; there must — to borrow a phrase from the architect — be an oblique bonding of the minute bricks of which its transparent mass is builded. Though w^e cannot even rebuild it from its solution, we know this must be so, for we can reproduce all the optical phenomena which it exhibits by an actual skew building of thin slices of another non-rotatory crystal. Here is an artificial ob- ject (I built it myself) constructed on Reusch's plan, from sixteen thin slips.of mica built up in staircase fashion — right-handedly — one above the other, and set symmetrically at equal angles of 45° to one another, the whole set making a cork-screw of two complete turns. In the lantern it behaves just as a quartz of about 9 millimetres thick- ness would do. It even gives tolerably perfect rings, as quartz does, when viewed by convergent light. I must now pass hastily onwards to the great discovery of Fara- day. Here (Fig 16) is a magnetising coil of wire M, having about 8300 turns, and enclosed in an iron jacket. When it is traversed by a powerful electric current from the dynamo machine, it produces an intense magnetic field along its axis. In this axial position lies a bar of heavy glass, not quite so dense as that which Faraday himself used, 1889.] on Optical Torque. 491 but nearly so. The bar lies along the line of light from our lantern, but the polariser P (the Ahxens reflector, Fig. 7), and analyser A (the Ahrens triple spar prism, Fig. 6), are crossed, so that here is the (^ark field. On turning on the current, light is at once restored, being twisted to the right when the current circulates right-handedly. To measure the rotation, I must turn the analyser ; and now I find that, owing to the greater rotation of blue waves than of red, complete extinction does not occur. Introducing a half-shadow plate, and using coloured glasses, it is very easy to verify the greater amount of rotation for blue light, and to show that reversing the current reverses the rotation. You will perhaps better understand it if I use (as in Fig. 16) the 24-ray star S, which I have previously employed. It is now obvious to you that there is a large rotation — over 50^ in fact — v\ hich is reversed when I reverse the magnetising current. We have here the fundamental experiment of magneto-optics. But now we meet with another consideratioD. Eeflect that the circulation of current, if it be taken as right-handed when regarded from one end of the coil, will be left-handed when regarded from the other end of the coil. Fig. 16. I 'jection of magnetic rotation of light. C, condensing lenses ; P, reflecting polariser ; lagnetising coil surrounding bar of heavy glass ; S, mica star of twenty-four rays ; A, analyser (Ahrens's triple prism). his is, therefore, no case of skew symmetry ; it clearly indicates that )mething is going on in the glass which tends to twist the light quite respective of which way the light enters. The next magneto-optic phenomenon is that discovered by Dr. Kerr the rotation of the plane of polarisation by reflection at the surface 'a magnet. To observe this at all requires good apparatus and a 3en eye. So far as I am aware, it has never been projected on the reen. If I can succeed in doing so, it will only be because I have lecial means of the most favourable character for so doing. We ithdraw the bar of heavy glass from the coil, and replace it 'ig. 17) by an iron core polished at its coned end. This will be : tensely magnetised when the current is turned on. Now we must throw the beam of light obliquely down the hollow < the coil, polarising it by one of my improved Nicol prisms P, as Vol. XII. (No. 83.) 2 l 49: Professor SUvanus P. Thompson [May 17, it goes down. After reflection it is focussed by a lens which sends it throucyh the analysing prism A. You see the dim spot of reflected Fig. 17. Apparatus for projecting rotation of plane of polarisation by reflection at pole of magnet. P, polariser ; M, magnetising coil with coned iron core ; A, analyser. light upon the screen. Xow for the current : " on," " off," " on," " off," Reversing its direction ought to double the aniount of torsion. Whilst Mr. Thomas is making the needful arrangements for the next experiment, I may mention that it was found by Kerr that the effect was approximately proportional to the magnetic induction through the iron. I have myself tried some further experiments : for example, using a bar of lodestone instead of an iron core. The light reflected from lodestone is also twisted. I should expect the ferro- aluminium alloy which Sir H. Roscoe showed us a fortnight ago to do the same thing, because that alloy is, as I have found, susceptible of macrnetisation. But I should not expect manganese steel to rotate the light, because of its singularly non-magnetisable nature. The experiment of Kundt, transmitting polarised light through a thin transparent film of iron, magnetised normally whilst the light is passing through it, is another difficult of repetition before an audience. The small disks here are covered with films of iron, kindly prepared for me by ^Ir. Crookes, by squirting them electrically in a hif^h vacuum. But the thin ones barely transmit enough light to make the observation of the effect possible, even to the solitary observer. I have observed the efiVct projected on the screen, using this very coil and these transparent mirrors. It requires, however, an absolutely dark room, and is at best so faint that it would be hopeless to attempt to show it to a large audience. Professor Kundt has not only observed similar rotations in other magnetic films of nickel and cobalt but has even shown that the degree of rotation of the light is proportional not to the magnetising force, but to the resulting mag- netic induction. This is a result of utmost importance in considering the theorv of the phenomenon. He has further shown that whereas the mafynetic rotations in elementary bodies, whether magnetic or dia- macmetic, are in the same sense as that in which the current circulates, the ma^metic rotations in compound magnetic bodies, such as a solution of sulphate of iron in water, are in the opposite sense. 1889.] on Optical Torque. 493 These experiments with transparent mirrors of iron raise interest- ing speculations as to the probable nature of a transparent magnet, if such there could be. It is one of the cardinal points of Maxwell's celebrated electro-magnetic theory of light, that the better a bodv conducts electric currents, the greater is its tendency to absorb light and become opaque. Xow, suppose it were possible to obtain a substance such as to possess greater electric conductivity in one direction than in another, such a substance ought to absorb those vibrations of light which are executed in the direction of the greater electric conductivity more than those in the direction at right angles. In other words, such a substance ought, like the tourmaline, to polarise light by absorption. Now, since the researches of Sir W. Thomson in 1856, we have known that the electric conductivity of iron is altered in the direction of the magnetic lines of force, when it is powerfully magnetised. More recently it has been discovered — I myself observed it in tinfoil, and announced the discovery to the Physical Society a few days before the announcement of the same fact by Eighi — that non-magnetic metals alter their resistance in the magnetic field. Notably so do bismuth and tellurium. I had therefore conceived it possible that a film of iron or possibly of tellurium, if strongly magnetised in its own plane, might exhibit polar absorption and act like a tourmaline. Unfortunately, if the effect exists it is so faint as to be yet undiscovered, though I have made many efforts to find such. I have further tried to oblain a similar result by making a transparent maguet out of a film of magnetic oxide of iron, precipi- tated chemically. In this too 1 have not succeeded. I have tried to precipitate a transparent film cf magnetic oxide in the midst of a transparent jelly. And I have mixed particles of precipitated oxide with melted gelatine so as to get a fi.lni. In this way I hoped to get, by placing the preparation in a strong magnetic field, a sort of mag- netic structure which would operate upon waves of light. That such a task was not hopeless was shown by two facts : first, that many mere vegetable and animal structures can act as polarisers ; and second, that a mere film of paint, such as indigo, can, if a proper mechanical drag is given to it so as to produce structure, also act as a polariser. The film of indigo-carmine which I have here, acts nearly as strongly, though not quite as evenly, as a tourmaline slice, and costs but a fraction of a penny. Well, my films of jelly enclosing particles of magnetic oxide of iron do faintly act on polarised light : but their action is not as marked as that of films of jelly enclosing actual small scraps of iron. This film, when placed across the poles of this electromagnet, betsveen two crossed Xicols at -ib', sLows an action when the magnet is tiirntd on, as you see by the way in which it flashes into light in the dark field. When the jelly is fresh, and of the proper consistency, the action is very strong, but with the rather dry sample before you I fear we can only call the effect a &ucch d'estime. Incident-all V. in the course of tliese experiments on magnetic films, ■2 L 2 494 Professor Silvanus P. Thompson [May 17, I came across a new magnetic body unknown hitherto, I believe, to the chemist, namely, a magnetic double oxide of cobalt and iron — a ferroso-cobaltic oxide, I think — a black powder, a sami:)le of which I have here. It also occurred to me, as a matter of speculation, that if I could strongly magnetise a crystal of ferrous sulphate ornickelous sulphate, whilst viewing it by convergent polarised light, I might find some in- teresting phenomena, which should, if they existed, show some sort of a relation between the direction of the optic axis and that of the lines of the magnetic field. I thought that a longitudinal magneti- sation might possibly set up a rotatory phenomenon like that in quartz in so far as to disturb the central field between the arras of the black cross ; however, not by the most powerful magnetising could I discover any such effect. Again, I thought that by magnetis- ing transversely to the optic axis I might possibly succeed in turning the uniaxial crystal into a biaxial, or producing by magnetism an efi"ect resembling the action of heat on crystals of selenite. Owing probably to the small depth of any crystals that can be obtained, I have failed so far to obtain any such effect, though I am convinced that it must exist. An effect precisely analogous to the magnetic effect which I vainly sought has, however, been lately discovered by Prof. Eontgen. I sought a distortion of the optic axis by transversely magnetising, and I sought it in crystals of sulphate of nickel ; he has found a distortion of the optic axis by transversely electrifying, and he has found it in crystals of quartz. Suppose a piece of quartz crystal is cut as a square prism, its long faces being principal planes of section respectively parallel to and at right angles to two of the natural faces of the hexagonal prism. Fig. 18 shows the form of the portion cut. The + and - signs in this Fig. 19. figure refer to the pyro- electric poles of the crystal. Such a piece viewed by convergent light shows the usual rings and black cross with a coloured centre (Fig. 19). If now two opposite faces be covered with tinfoil, and the crystal be electrified transversely, the rings are distorted into lemniscates, the direction of the distortion changing with the sign of the electrification. It is necessary to use a red 1889.] on Optical Torque. 495 glass, or still better sodium liglit, to observe the changes in form on reversing the sign of the charges. Figs. 20 and 21, 22 and 23, show the changes of form, but these sketches grossly exaggerate the effects. As you see upon the screen, when the charges imparted by this fine Wimshurst machine are rapidly reversed, there is a decided distortion of the rings, but it is small in amount. Fig. 20. Fig. 21. Fig. 22. Eeturning to the phenomena of the rotation impressed by magnet- ism on polarised light, I may point out that the torque which a magnetic field exerts on the light waves appears to be really an action upon the matter through which the light- waves are passing. It is as though the magnetic field were really a portion of space rotating rapidly on itself, or perhaps as though the ether were there rotating, and that this rotation in some way dragged the particles of matter along with it. It has long been supposed necessary, in order to account for the refractive and dispersive properties of transparent bodies, to consider that their particles are in some way concerned in and partake of the vibrations going on in the ether within them or between their molecules. It is impossible to explain the phenomena of magneto-optic rotation by the supposition that any skew structure is imparted to the medium ; for these phenomena unlike those of quartz, do not exhibit skew symmetry. There seems to be no other way of explaining the magneto-optic torsion of light than by suppos- ing that the molecules of matter in the magnetic field are actually subjected to rotatory actions ; as indeed was suggested long ago by Sir William Thomson. However, there is room here not only for speculation but for ex- periment. Some day, when facts enough have been collected, we shall 496 Professor Silvanus P. Thompson [May 17, be ready to build thereon the wider generalisation wbicli at present seems to escape ns. So far we have been applying an optical torque to previously polarised light, and producing a torsion of it. It remains for me yet to describe the means by which, in the hands of Professor Abbe and Professor Sohncke, it has been demonstrated that natural, non-polarised light is actually rotated when subjected to an optical torque. The way of doing this is to make use of the principle of in- terference. Here is the slit from which a narrow beam of light- waves issues. At a point a little distance away is a Fresnel's biprism which splits up the light (without polarising it) into two beams, just as if we had two slits or sources of light. These two beams pass along, and meet uj)on this distant screen, and give us — what ? A set of interference fringes having a bright line down the middle, because this part of the screen is exactly equidistant from the two sources of light. But these dark interference fringes that lie right and left can only exist because, in the first place the vibrations have travelled unequal paths differing by an odd number of half wave-lengths ; and secondly, because (owing to the method adopted of using two images of one slit) the phases of the emitted waves from the two sources are identical. This being so, let us now introduce across the two interfering beams of light a special biquartz, made of right-and-left handed quartz of only 1 • 88 mm. thick. This will rotate — if it rotates natural light at all — the yellow light in one beam 45^ to the right and that of the other beam 45° to the left. The angles will be a little more for green and blue, a little less for red and orange. Con- sequently we shall not get quite a perfect result for all kinds of colours. But for the main body of the light the result is this : that because the two beams have had their respective vibrations turned so that, whatever their primitive positions, they are now at right angles to one another, they cannot interfere. In other words, if it be true that the quartz rotates natural light, the interference bands will die out. [Experiment shown.] Here I have the light passing through the biprism only, and giving us this narrow series of interference bands. You must notice carefully — with opera-glasses if you have them — the narrow bright and dark stripes. Now I shift this little diapliragra so that the light passes through the biquartz as well. Instead of sharp interference bands we have merely a dull line of nebulous light. The disappear- ance of the fringes proves that quartz does twist the non-previously polarised waves of light. That the magnetic field can also exert a magnetic torque on non- polarised light is readily proved, at least when one already has the biquartz. Two strips of heavy glass of exactly equal length and similar quality, such as those I hold in my hand, must be introduced in the respective i:>aths of the two beams : and one at least of them must be surrounded by a magnetising coil. The biquartz has wiped 1889.] on Optical Torque. 497 out the interference fringes ; but on magnetising one of the two pieces of heavy-glass, or on magnetising the two in opposite senses, the interference bands can be made to reappear. It is in this way that Professor Sohncke's experiment — hardly suitable for a lecture theatre — was performed. It is in this way that we establish upon an experimental basis the fact that light itself, and not merely the plane of its polarisation, experiences an optical torsion when subjected to those forces which, whether crystalline, molecular, or magnetic, exert upon it an optical torque. [S. P. T.] 498 Bev. S. J Perry [May 24, WEEKLY EVENING MEETING, Friday, May 24, 1889. Sir James Crichton Browne, M.D, LL D. F.E.S. Vice-President, in tlie Chair. The Eev. S. J. Perry, D.So. F.E.S. F.E.A.S. Director of Stonyhurst College Observatory. The Solar Surface during the Last Ten Years. The solar surface is a subject on whicli so much has been written of late years, that it would be highly unsatisfactory to attempt in one short hour even a brief enumeration of the results obtained and the theories advanced by the many eminent men who have devoted atten- tion to this branch of solar physics. The end which I propose to myself this evening, and which, I venture to think, is most in accor- dance with precedent in these discourses, is to lay before you, in as clear a manner as I am able, the results obtained at the observatory to which I am attached, in so far as they enter into our present subject, and to touch upon the work of others in such a manner only as to complete the picture, by showing the bearing of our labours on the general result. For the last ten years I have been anxiously endeavouring to make Stonyhurst as efficient an observatory for solar physics as the means at my disposal would admit, so I was naturally desirous not to undertake any work that would be a mere repetition of what was being done better elsewhere. From the outset, therefore, I excluded from my programme a daily photograph of the sun, as this had been already undertaken at the Eoyal Observatory, assisted by other Government observatories in India and at Mauritius, and the most I could have hoped for in this direction would have been to fill up a few gaps in an almost perfect series. My choice, therefore, lay between drawings made at the telescope by aid of a solar eye-piece, and the use of a sketch-board on which the sun's image could be projected. The object in view being to procure the most complete and faithful repre- sentation of nature, I had no hesitation in rejecting all forms of solar eye-pieces, as by this method of observation too much is left to the imagination of the draughtsman ; although a solar prism is not unfrequently of great advantage in supplementing other methods of attack, especially when delicate details require verification. The sketch-board, on the other hand, may be so used as to leave very little indeed to the ideas or bias of the observer. To effect this the follow- ing method has been adopted. A circle ten and a half inches in 1889.] on the Solar Surface during the Last Ten Ye.irs. 499 diameter is first traced upon a piece of drawing paper, which is pinned to a board just rigid enough to hold the paper firmly, and then the whole is clamped on to the eye-end of the telescope. The eye-piece and board are each capable of fine adjustment, so that the sharpest image of the sun may be made just to fill the lOJ-inch circle, and a marked diameter of the picture is brought into precise coincidence with the direction of the daily motion. The clock-work of the equa- torial then keeps the image fixed in position on the paper, whilst an accurate outline is traced of the umbra and penumbra of every spot visible on the disk. When the sky is clear this outline can be made as correct as the finest point of a hard pencil can delineate it ; and even when, as so often happens, the transparency of the atmosphere is changing every moment, a short time at the instrument will generally enable the observer to verify the perfect accuracy of his sketch. The details are then filled in as quickly as the nature of the sky permits, each portion of the drawing being over and over again brought into coincidence with the projected image, in order to detect and remove the slightest difference between them. By this means the final picture gives the advantage of all the best moments of seeing that occur during the progress of the observation, and not merely the result at one single moment, which maybe far from the best for definition even on the finest day. Immediately the spots have been completed the faculse are traced, and their details rejiroduced as nearly as possible. By the advice of Prof. Stokes, P.E.S., ar red pencil is used in drawing the faculse, and thus the difference between bright and dark markings and their connection with each other, stand out much more boldly than if the same black pencil were used throughout. Finally, when the sky is good for definition, the general surface of the sun is care- fully scrutinised for some time, and any peculiarities noted. The sun's image having thus been sketched and examined, the drawing-board is re[)laced by an automatic sj)ectroscope of six prisms of 60°, through each of which the light may be made to pass twice, and to which may be added a Hilger-Christie half-prism, raising the total available dispersion to about 36 prisms of 60°. The chromo- sphere is measured with the slit radial, a dispersion of six prisms being generally used ; and when the definition is very good, a sweep is made round the limb, with 12 prisms and a tangential slit, to study the forms of the prominences and the direction of the currents in the chromosphere. Spot-spectra have been occasionally observed with the same instrument ; but lately (in a room adjoining the equatorial dome) a large grating has been mounted, with which it is proposed to take daily photographs and eye-measurements of the spectra of sun- spots. A heliostat and a 5J-inch object-glass of Alvan Clark are used in connection with the grating spectroscope. The combination of this solar observatory with an establishment supplied with a com- plete set of self-recording meteorological and magnetic instruments, affords a ready opportunity of comparing solar results with the daily photographic records of terrestrial phenomena. 500 Bev. S. J. Perry [May 24, As it is most important, before referring to any conclusions that may be drawn from our observations, to test severely the fidelity of which solar drawings are capable, I will throw upon the screen a number of sun-pictures drawn at Stonyhurst, and enable you to contrast them with sketches of the same spots made by experienced astronomers in England, and at Brussels, Palermo, and Kalocsa, and also with photographs taken at Dehra Dun and at Meudon ; and I think these few examples will amply suffice to vindicate a high character for solar drawings. But 1 have not been satisfied with this ready comparison, and lately this solar work has been put to a more rigid test of accuracy by placing side by side the measurements of areas obtained from drawings and photographs ; and here again the hand-sketch by projection seems to bear well the scrutiny. The method of projection not only permits the area covered by spots and faculsB to be accurately determined, but it also furnishes precise data for finding the heliographic co-ordinates of any mark upon the solar surface. These, however, are now given so fully in the annual publications of the Eoyal Observatory, and each in- dividual spot can be so readily identified, that an indejjondent calculation would be a mere waste of time and energy. The results, therefore, dependent on position alone, are deduced immediately from the Greenwich Tables. The decade of years which we are now considering, covers almost an entire solar cycle, that period of eleven years the proof of whose existence was the fruit of the unwearied labours of Baron Schwabe, in his daily observations from 1826 to 1868. The present cycle falls much below that which preceded it in the extent of its sj)otted area, but it is remarkable for the duration of its maximum period. The last minimum occurred about November 1878, and therefore, if we accept the mean values 3 • 7 and 7 • 4 as the number of years from minimum to maximum and from maximum to minimum respectively, we obtain 1878 '9 -}-3*7 = 1882 6 as the date of the maximum of the cycle, and 1882*6 + 7*4 = 1890*0 as the epoch of the approaching minimum. Many facts seem to. support this con- clusion. Thus, the greatest sun-spot area occurred on April 21, 1882, and the largest individual spot was at its maximum on November 18 of the same year, when it covered almost one four- hundredth of the visible hemisphere. The total spot area in April reached, however, the much higher figure of one one-hundred-and- eightieth, or about 6,000,000,0.0 square miles, which on the following day had diminished to something under 4,000,000,000, showing the marvellous activity of the solar forces at that epoch. In the same year also the mean monthly amount of umbra was greater in April and in November than at any other time of the cycle, making it highly probable that the disturbances then pene- trated more deeply below the surface of the photosphere. Again, if we consider the mean latitude of the spotted area, its value at the maximum seems also to favour the claims of 1882 ; and these are 1889.] on the Solar Surface during the Last Ten Years. 501 still more strengthened by the number of times in which the spectral lines have been found contorted in the observations of the chromo- sphere. Bat, on the other hand, it may be urged, that if we reckon the days without spots, we find very little change from 1880 to the beginning of 1885 ; and the monthly mean area of sun-spots was slightly in excess in July 1883 of what it had been in the previous year ; and even as late as June 1885 we meet with days on which the spotted area was larger than the mean extent for any month in 1882 or 1883. May it not be possible that the great comet of 1882, which passed so deep within the limits of the corona, and which seems to be but one of a numerous family, may have exercised some disturbing influence, and been a partial cause of this prolonged maximum ? The limits are rather wide for the periods separating maximum from maximum, but there is much more steadiness in the lapse of time between successive minima, and if we may judge from the present rapid increase in the number of days without spots, the next minimum should be fast approaching, and may not be far removed from the computed epoch of Januarv 1890. Thus, against one spotless day in 1884, we have 10 for 1885, 61 for 1886, 106 for 1887, 160 for 1888, and more than half the days that have been fit for observation since the beginning of the present year. The im- portant law connecting the mean latitude of sun-spots with their extent of area, first published by Carrington, and afterwards so vividly represented in curves by Prof. Sporer, has received a fresh verification in the present cycle. In close relation to this is the distribution of spots in the two hemispheres, and this can be well illustrated by aid of curves and by mapping each spot in its true heliographic position. Thus we find that the greater activity of the southern hemisphere since 1883 is strongly marked, and there seems to be very little evidence that successive spots tend to form along meridians, although examples of this are not wholly wanting. A general glance at spot distribution shows that an outbreak may be expected on any meridian, but that at certain times spots congregate more thickly in one longitude than in another. Thus in 1881 and 1882 the longitudes most favoured lie between 180^ and 270°, whilst in 1887 more spots appeared between 0" and 90°. The preponderance of southern spots in this year is very striking. The variability of the sun-spot area which we have been so far considering, is a point of the greatest interest in solar physics, and it may even become of great practical importance, if the supposed connection between certain terrestrial phenomena and solar cycles is once clearly established. But apart from this, the study of spots in themselves, their wonderful changes, and their individual history, may be highly instructive and teach us much concerning the nature of the solar surface. The spots seen first in March and April 1884, and which reappeared in May and June and July, furnish excellent examples of the formation of companion groups, the principal spot acquiring a 502 Rev. S. J. Perry [May 24, regularity of outline when it stands alone in middle life, and re- gaining new companions as it hurries on to its final extinction. The last few years have also afforded some striking instances of the repulsion and proper motion of spots, so clearly brought out in the researches of Carrington. Perhaps the most remarkable change of this nature recorded at Stonyhurst occurred between May 27 and 28 in 1884, when a spot of considerable size, situated between two others, moved through a great part of the distance separating its two companions. Another class of observations consists in noting the variety of tints connected with the bridges and other bright portions of intricate spots, and which are seen only from time to time. Thus, in 1884, on the 5th of May and the 6th of July, there were outbursts of a crimson hue in the centre of spots. Such appearances vary in dura- tion as much as in colour. On one occasion a reddish brown tint, very noticeable on the bright separations of the umbra of a spot, did not remain constantly visible, but was intermittent. At another date a yellowish green tint remained visible for several days on the bridge crossing a spot. In each case the coloured portion was carefully compared with other parts of the disk, so as to ascertain whether the effect might not be due to the object-glass or eye-piece. Some useful hints in view of futare theory can certainly be gained by a careful study of the peculiar forms assumed occasionally by the penumbra of spots, not when tbe whole area is in a state of violent commotion, for then it is conceivable that any form may possibly present itself, but when the umbra is regular and the spot quiet. I would especially draw attention to some examples of multiple penumbra observed in 1882 and 1883, which seem to indicate that such disturbances are due to successive imjiulses from a common centre. Or, again, I would point to the penumbral matter extending from the nucleus of certain spots in 1884,, which might reasonably be adduced as evidence of an ai)2^arcnt outflow of a floating substance. It is doubtless fascinating to argue in support of some exhaustive theory, complete in itself, and able alone to offer a satisfactory explanation of every observed appearance ; but may it not be possible that several true causes concur in the production of solar phenomena ? And if this be admitted, then a line too hard and fast may easily stand in the way of the true explanation of spot formation. Might not the last mentioned observations suggest the question, whether absorbent vapours may not sometimes be cast up from the seething mass beneath, although a down-rush be the prevailing feature of a sun-spot ? The study of the bright markings on the solar surface is perhaps somewhat less interesting, although almost equally important as that of the spot area, but the state of the sky interferes much more seriously with the former class of observation than with the latter. The clustering of faculae about nascent spots, their spreading as the spots gets older, their lingering long after the parent spots have 1889.] on the Solar Surface during the Last Ten Years. 503 disappeared, the apparition of fresh spots in tlieir midst, are facts of constant recurrence. That facul^e are the first evidence of a coming disturbance has never been observed at Stonyhurst, but a region where fiicula3 abound has always been found to have previously been occupied by a group of spots. Such an observation as that of the birth of the great November spot of 1882, and other similar instances are not wanting, in which a few dots, in a region of perfect calm, suddenly develojDed into a vast centre of disturbance, is a strong proof that the law which regards faculae as the constant forerunners of spots, cannot be accepted as universal. Do not such instances as these give some additional weight to the opinion that large spots owe their origin rather to an external cause, as the prime mover, than to the internal forces of heat and pressure and chemical affinity? Might not the latter forces, however great, hold each other almost in equilibrium until their energies are freed by the advent of an external, though perhaps lesser, disturbing force ? The periodicity of sun- sj^ots, their total absence for months, nay almost even for years, com- bined with their enormous development and rapid changes about the epoch of maximum area, seems to preclude the possibility of internal forces, in a gaseous body, being the sole cause of such phenomena ; although there appears to be no reason why these forces should not exercise an overwhelming influence when called into play by an external agent. The distribution of faculse, especially of small isolated patches, is much more general than that of spots, many being visible even near the sun's poles, and this has been forced upon my attention more and more of late as we have aj)proached nearer the minimum of the cycle. Another point, which is often accepted as established, is the lagging of faculae, and it is sometimes adduced as a proof that faculre are cast up from a lower level, for thus, in possessing a less linear velocity than the surrounding photosphere, they would naturally be left behind. The observations of the present cycle can scarcely be said to add to the stringency of this argument, as out of more than 4000 cases recorded in the Greenwich Tables, 74 per cent, lean neither way, and of the remainder 5 • 7 per cent, show the faculae preceding, against 20-3 per cent., which alone are in direct confirmation of the assumed law. The general surfiice, with its ever varying aspect, can never be adequately represented by the pencil, but in this case recourse must be had to the instantaneous photograph. And yet it is true to say that even in this branch of the subject much may be done by the method of projection, and light may thus be thrown on many points which could scarcely be settled by photography alone. I refer particularly to any possible variation of tint in definite regions of the solar disk, to rapid and continuous changes, and to such appearances as the smugged areas in the photographs, which suggest at first bad definition, but which are in reality evidence of a new form of distur- bance not indicated by other phenomena. Watching the image of 504 Bei'. S. J. Perry [May 24, the sun as it depicts itself upon the drawing-board, we soon perceive that no i^art of the surface is long at rest. Everywhere are seen small dark shadowy objects, attracting special attention now in one place and then in another, sometimes forming groups, and at other times almost compauionless, affecting no special zone, and combining with no other form of solar marking, except occasionally with a few bright faculse. These dim ill-defined objects seem first to have been observed in 1875 by Trouvelot, who gave them the name of veiled spots. They soon forced themselves into notice w^hen our daily sun- work was started at Stonyhurst, and ever since they have never failed to be carefully watched. At first they were divided, for convenience, into three classes, but on further examination there seems to be no need of more than a single distinction. When they first catch the eye all IH'esent much the same general appearance, resembling small frag- ments of ill-defined penumbra, but their position on the disk, and still more their duration, soon enable the observer to distinguish the class to which they belong. Those of the first class appear in all heliographic latitudes, and never remain visible for more than two or three minutes ; whilst the others, which have been called sub-permanent spots, are confined exclusively to the spot zones on either side of the equator, and this class may remain on the disk for two or more days. Sub-permanent spots are not always to be found on the surface of the sun, their tint is a shade less dull than that of the other veiled spots, and occasionally there is almost the appearance of an umbra in their midst, though this rarely could be mistaken for a true umbra. For even when their shading is in some parts more intense than in others, the whole remains always ill-defined, and the limits of its several parts are hard to distinguish. Frequently these dim objects show themselves in considerable numbers in the neighbourhood of fully developed spots, but then the latter are generally approaching their time of dissolution. They may, perhaps, aptly be described as imperfectly developed, or penumbral spots, and consequently be included in the ordinary spotted area. But it is quite otherwise with the first class of veiled spots, which except for their diminished brilliancy would have nothing in comman with the fully developed sun-spots. Seen in all solar latitudes, they are never absent from the sun, being, with good definition, as frequent and as visible at the epoch of spot maximum as at minimum, but catching the eye more readily when markings more intense are absent from the surface. The most striking characteristic of this class of spots is the rapidity with which they invariably disappear ; but although no individual spot ever lasts more than about three minutes, the first seen may be joined in quick succession by a multitude of others similar to itself, and thus transform vast areas, and give to portions of the solar surface that blurred appearance which is so marked a feature in Janssen's magnificent sun-pictures. The general distribution of these faint objects, their evanescent character, and their ill-defined appearance, 1889.] on the Solar Sur/ace during the Last Ten Years. 505 seem to connect them more immediately than any other feature of the solar surface with the vertical convection currents which form so important a part of the sun's internal economy. One exceptional observation of the formation of veiled spofcs may be of interest, as showing the strange phenomena we may occasionally witness by a lengthened examination of the solar image. At lOh. 15m. one morning a group of spots was visible on the sun, and presented no very special feature ; less than half an hour later the leader of the group had apparently shot out a number of minute bodies, and then five minutes sufficed for all these to be transformed into veiled spots, which disappeared as rapidly as usual. Instances have not been wanting of other moving bodies seen upon the solar surface, always rapid in their course, and sometimes disappearing without crossing the limb. I refer, of course, only to observations in which every precaution was taken to test the objective nature of these bodies, as false images might so easily deceive a tired retina, especially after exposure to a strong light. But there would be little use in dwelling upon even well-established cases of this nature, as they all probably find their explanation in the passage of bodies between the sun and the observer, and promise very little additional light for an inquiry iLto the nature of the solar photosphere. Before concluding these few words on a series of solar obser- vations of the last ten years, I may be expected by some to add one more to the already long list of solar theories, or at least to pass in rapid review the most plausible theories that up to the present time have been advanced for reducing to harmony all the well-established facts regarding the sun with which we are acquainted. But con- sidering the scope of my discourse, which has dwelt mostly on the work done at a single observatory, and, even so, has only treated in detail one method of examining the solar photosphere, I should not be warranted in advancing any theory of my own, or in judging of the theories of others, without first considering the many important facts connected with our subject which the spectroscope has taught us and also extending my researches to the solar chromosphere and the corona. It is only by diligently collating the facts laboriously accumulated by telescope and siDcctroscope in every known region of the sun that we may hope at last to build up a complete and satisfactory solar theory. Much has already been achieved in this direction, and we are in possession not only of reliable data, but also of important deductions therefrom, which may serve as a solid foundation for some future superstructure. I may have added, perhaps, some little towards the completion of the edifice, if I have convinced you this evening, that by the persevering and judicious use of the pencil we may yet hope to throw some light on questions of solar physics, that might not|_so readily have been secured by any other means. I S. J. p. ] 506 Dr. D. MendeUeff [May 31 WEEKLY EVENING MEETING, Friday, May 31, 1889. Sir Fbederick Abel, C.B. D.C.L. F.R.S. Yice-Presklent, in the Chair. D. Mexdeleeff, Esq. LL.D. PROFESSOR OF CHEMI.STKT IX THE UXnERSITT OF ST. PETERSBURG. An Attempt to apply to Chemistry one of the Frinciples of Newton 8 Natural Philosopliy . Nature, inert to the eyes of the ancients, has been revealed to us as full of life and activity. The conviction that motion pervaded all things, which was first realised with respect to the stellar universe, has now extended to the unseen world of atoms. No sooner had the human understanding denied to the earth a fixed position and launched it along its path in space, than it was sought to fix immov- ably the sun and the stars. But astronomy has demonstrated that the sun moves with unswerving regularity through the stur-set universe at the rate of about 50 kilometres j^er second. Among the so-called fixed stars are now discerned manifold changes and various orders of movemeut. Light, heat, electricity — like sound — have been proved to be modes of motion ; to the realisation of this fact modern science is indebted for powers which have been used with such brilliant success, and which have been expounded so clearly at this lecture table by Faraday and by his successors. As in the imagination of Dante, the invisible air became peopled with spiritual beings, so before the eyes of earnest investigators, and especially before those of Clerk Maxwell, the invisible mass of gases became peopled with particles : their rapid movements, their collisions, and impacts became so manifest that it seemed almost possible to count the impacts and determine many of the peculiarities or laws of their collisions. The fact of the existence of these invisible motions may at once be made apparent by demonstrating the difi'erence in the rate of diffusion through porous bodies of the light and rapidly moving atoms of hydrogen and the heavier and more sluggish particles of air. Within the masses of liquid and of solid bodies we have been forced to acknowledge the existence of persistent though limited motion of their ultimate particles, for otherwise it would be impossible to explain, for example, the celebrated experiments of Graham on diffusion through liquid and colloidal substances. If there were, in our times, no belief in the molecular motion in solid bodies, could the famous Spring have hoped to attain any result by mixing carefully dried powders of potash, saltpetre, and acetate of soda, in order to produce, by pressure, a chemical reaction between these substances through the interchange 1889.] on an attempt to apply to Chemistry, dc. 507 of their metals, and have derived, for the conviction of the incredulous, a mixture of two hygroscopic though solid salts— nitrate of soda and acetate of j^otash ? In these invisible and apparently chaotic movements, reaching from the stars to the minutest atoms, there reigns, however, a harmonious order which is commonly mistaken for complete rest, but which is really a consequence of the conservation of that dynamic equilibrium which was first discerned by the genius of Newton, and which has been traced by his successors in the detailed analysis of the particular consequences of the great generalisation, namely, relative immovability in the midst of universal and active movement. But the unseen world of chemical changes is closely analogous to the visible world of the heavenly bodies, since our atoms form distinct portions of an invisible world, as planets, satellites, and comets form distinct portions of the astronomer's universe ; our atoms may there- fore be compared to the solar systems, or to the systems of double or of single stars, for exaniijle, ammonia (NH^) may be represented in the sim2)lest manner by supposing the sun nitrogen surrounded by its planets of hydrogen ; and common salt (NaCl) may be looked upon as a double star formed of nitrogen and chlorine. Besides, now that the indestructibility of the elements has been acknowledged, chemical changes cannot otherwise be explained than as changes of motion, and the production by chemical reactions of galvanic currents, of light, of heat, of pressure, or of steam power, demonstrate visibly that the processes of chemical reaction are inevitably connected with enormous though unseen displacements, originating in the movements of atoms in molecules. Astronomers and natural j^hilosophers, in studying the visible motions of the heavenly bodies and of matter on the earth, have understood and have estimated the value of this store of energy. But the chemist has had to pursue a contrary course. Observing in the physical and mechanical phenomena which accom- pany chemical reactions the quantity of energy manifested by the atoms and molecules, he is constrained to acknowledge that within the molecules there exist atoms in motion, endowed wdth an energy which, like matter itself, is neither being created nor is capable of being destroyed. Therefore, in chemistry, we must seek dynamic equilibrium not only between the molecules but also in their midst among their component atoms. Many conditions of such equilibrium have been determined, but much remains to be done, and it is not uncommon, even in these days, to find that some chemists forget that there is the possibility of motion in the interior of molecules, and therefore re]3resent them as being in a condition of death-like inactivity. Chemical combinations take place with so much ease and rapidity ; possess so many special characteristics, and are so numerous, that their simplicity and order was for a long time hid from investigators. Sympathy, relationship, all the caprices or all the fancifulness of human intercourse, seemed to have found complete analogies, in Vol. XII. (No. 83.) 2 m 508 Dr. D. Mendeleeff [May 31, chemical combinations, but with this difference, that the characteristics of the material substances — such as silver, for example, or of any other body — remain unchanged in every subdivision from the largest masses to the smallest particles, and consequently their characteristics must be a property of its particles. But the world of heavenly luminaries appeared equally fanciful at man's first acquaintance with it, so much so, that the astrologers imagined a connection between the in- dividualities of men and the conjunctions of planets. Thanks to the genius of Lavoisier and of Dalton, man has been able, in tlie unseen world of chemical combinations, to recognise laws of the same simple order as those which Cojjernicus and Kepler proved to exist in the planetary universe. Man discovered, and continues every hour to discover ivhat remains unchanged in chemical evolution, and how changes take i^lace in combinations of the unchangeable. He has learned to predict, not only what possible combinations may take place, but also the very existence of atoms of unknown elementary bodies, and has besides succeeded in making innumerable practical applications of his knowledge to the great advantage of his race, and has accomplished this notwithstanding that notions of sympathy and affinity still preserve a strong vitality in science. At present we cannot apply Newton's principles to chemistry, because the soil is only being now prepared. The invisible world of chemical atoms is still waiting for the creator of chemical mechanics. For him our age is collecting a mass of materials, the inductions of well-digested facts, and many-sided inferences similar to those which existed for Astronomy and Mechanics in the days of Newton. It is well also to remember that Newton devoted much time to chemical experiments, and while considering questions of celestial mechanics, persistently kept in view the mutual action of those infinitely small worlds which are concerned in chemical evolutions. For this reason, and also to maintain the unity of laws, it seems to me that we must, in the first instance, seek to harmonise the various phases of contemporary chemical theories with the immortal principles of the Newtonian natural philosophy, and so hasten the advent of true chemical mechanics. Let the above con- siderations serve as m}^ justification for the attempt which I propose to make to act as a champion of the universality of the Newtonian principles, which I believe are competent to embrace every jjheno- menon in the universe, from the rotation of the fixed stars, to the interchanges of chemical atoms. In the first place I consider it indispensable to bear in mind that, up to quite recent times, only a one-sided affinity has been recognised in chemical reactions. Thus, for examjile, from the circumstance that red-hot iron decomposes water with the evolution of hydrogen, it was concluded that oxygen had a greater affinity for iron than for hydrogen. But hydrogen, in presence of red-hot iron scale, appro- priates its oxygen and forms water, whence an exactly opposite conclusion may be formed. During the last ten years a gradual, scarcely perceptible, but 1889.] on an attempt to apply to Chemistry, dc. 509 most important change has taken place in the views, and consequently in the researches of chemists. They have sought everywhere, and have always found systems of conservation or dynamic equilibrium substantially similar to those which natural philosophers have long since discovered in the visible world, and in virtue of which the position of the heavenly bodies in the universe is determined. There where one-sided affinities only were at first detected, not only secondary or lateral ones have been found, but even those w^hich are diametri- cally opj)osite, yet among these, dynamical equilibrium establishes itself not by excluding one or other of the forces, but regulating them all. So the chemist finds in the flame of the blast furnace, in the formation of every salt, and, with especial clearness, in double salts, and in the crystallisation of solutions, not a fight ending in the victory of one side, as used to be supposed, but the conjunction of forces ; the peace of dynamic equilibrium resulting from the action of many forces and affinities. Carbonaceous matters, for example, burn at the expense of the oxygen of the air, yielding a quantity of heat and forming products of combustion, in which it was thought that the affinities of the oxygen with the combustible elements were satisfied. But it appeared that the heat of combustion was competent to de- compose these products, to dissociate the oxygen from the combustible elements, and therefore, to explain combustion fully, it is necessary to take into account the equilibrium between opposite reactions, between those which evolve, and those which absorb heat. In the same way, in the case of the solution of common salt in water, it is necessary to take into account, on the one hand, the formation of compound particles generated by the combination of salt with water, and on the other the disintegration or scattering of the new particles formed, as well as of those originally contained. At l^resent we find two currents of thought, apj^arently antagonistic to each other, dominating the study of solutions : according to the one, solution seems a mere act of building up or association ; according to the other, it is only dissociation or disintegration. The truth lies, evidently, between these views ; it lies, as I have endeavoured to prove by my investigations into aqueous solutions, in the dynamic equilibrium of particles tending to combine and also to fall asunder. The large majority of chemical reactions which appeared to act victoriously along one line have been proved capable of acting as victoriously even along an exactly opposite line. Elements which utterly decline to combine directly may often be formed into com- paratively stable compounds by indirect means, as for example in the case of chlorine and carbon ; and consequently the symjDathies and antipathies, which it was thought to transfer from human relations to those of atoms, should be laid aside until the mechanism of chemical relations is explained. Let us remember, however, that chlorine, which does not form with carbon the chloride of carbon, is strongly absorbed, or, as it w^ere, dissolved by carbon, which leads us to suspect incipient chemical action even in an external and purely 2 M 2 610 Dr. D. Mendeleeff [May 31, surface contact, and involuntarily gives rise to conceptions of that unity of the forces of nature which has been so energetically insisted on by Sir William Grove and formulated in his famous paradox. Grove noticed that platinum, when fused in the oxyhydrogen flame, during which operation water is formed, when allowed to drop into water decomposes the latter and produces the explosive oxyhydrogen mixture. The explanation of this paradox, as of many others which arose during the period of chemical renaissance has led, in our time, to the promulgation by Henri St. Claire Deville of the conception of dissociation and of equilibrium, and has recalled the teaching of Berthollet, which, notwithstanding its brilliant confirmation by Heinrich Rose and Dr. Gladstone, had not, up to that period, been included in received chemical views. Chemical equilibrium in general, and dissociation in particular, are now being so fully worked out in detail, and applied in such various ways, that I do not allude to them to develop, but only use them as examples by which to indicate the correctness of a tendency to regard chemical combinations from points of view differing from those expressed by the term hitherto appropriated to define chemical forces, namely, " affinity." Chemical equilibria dissociation, the speed of chemical reactions, thermo-chemistry, spectroscopy, and, more than all, the determination of the influence of masses and the search for a connection between the properties and weights of atoms and molecules ; in one word, the vast mass of the most important chemical researches of the present day, clearly indicates the near a2)proach of the time when chemical doctrines will submit fully and completely to the doctrine which was first announced in the Principia of Newton. In order that the application of these principles may bear fruit it is evidently insuflicient to assume that statical equilibrium reigns alone in chemical systems or chemical molecules : it is necessary to grasp the conditions of possible states of dynamical equilibria, and to apj^ly to them kinetic principles. Numerous considerations compel us to renounce the idea of statical equilibrium in molecules, and the recent yet strongly supported appeals to dynamic principles consti- tute, in my opinion, the foundation of the modern teaching relating to atomicity, or the valency of the elements, which usually forms the basis of investigations into organic or carbon compounds. This teaching has led to brilliant explanations of very many chemical relations and to cases of isomerism, or the difference in the l^roperties of substances having the same composition. It has been so fruitful in its many applications and in the foreshadowing of remote consequences, especially respecting carbon compounds, that it is impossible to deny its claims to be ranked as a great achieve- ment of chemical science. Its practical application to the synthesis of many substances of the most complicated composition entering into the structure of organised bodies, and to the creation of an unlimited number of carbon compounds, among which the colours derived from 1889.] on an attem'pt to ap])ly to Chemistry, &c. 511 coal tar stand prominently forward, surpass the synthetical powers of Nature itself. Yet this teaching, as applied to the structure of carbon compounds, is not on the face of it directly applicable to the investi- gation of other elements, because in examining the first it is possible to assume that the atoms of carbon have alw^ays a definite and equal number of affinities, while in the combinations of other elements this is evidently inadmissible. Thus, for example, an atom of carbon yields only one compound with four atoms of hydrogen and one with four atoms of chlorine in the molecule, while the atoms of chlorine and hydrogen unite only in the proportions of one to one. Simplicity is here evident and forms a point of departure from which it is easy to move forward with firm and secure tread. Other elements are of a diflerent nature. Phosphorus unites wdth three and with five atoms of chlorine, and consequently the simplicity and sharpness of the application of structural conceptions are lost. Sulphur unites only with two atoms of hydrogen, but with oxygen it enters into higher orders of combination. The j)eriodic relationship which exists among all the proj)erties of the elements, such, for example, as their ability to enter into various combinations, and their atomic weiights, • indicate that this variation in atomicity is subject to one perfectly exact and general law, and it is only carbon and its near analogues which constitute cases of permanently preserved atomicity. It is impossible to recognise as constant and fundamental properties of atoms, powers which, in substance, have, proved 'to be variable. But by abandoning the idea of permanence, and of the constant saturation of afiinities — that is to say, by acknowledging the possibility of free affinities — many retain a comprehension of the atomicity of the elements " under given conditions " ; and on this frail foundation they build up structures composed of chemical molecules, evidently only because the conception of manifold affinities gives, at once, a simple statical method of estimating the composition of the most comj)licated molecules. I shall enter neither into details, nor into the various consequences following from these views, nor into the disputes which have sprung up respecting them (and relating especially to the number of isomers possible on the assumption of free affinities), because the foundation or origin of theories of this nature sufi'ers from the radical defect of being in opposition to dynamics. The molecule, as even Laurent expressed himself, is represented as an architectural structure, the style of which is determined by the fundamental arrangement of a few atoms, while the decorative details, which are capable of being varied by the same forces, are formed l3y the elements entering into the combination. It is on this account that the term " structural " is so appropriate to the contemporary views of the above order, and that the "constructors" seek to justify the tetrahedric, plane, or prismatic disposition of the atoms of carbon in benzole. It is evident that the consideration relates to the statical position of atoms and molecules and not to their kinetic relations. The atoms of the 512 Br. D. MendeUeff [May 31, structural type are like the lifeless pieces on a chess board : they are eudowed but with the voices of living beings, and are not those living beings themselves ; acting, indeed, according to laws, yet each possessed of a store of energy, w^hich, in the present state of our knowledge, must be taken into account. In the days of Haiiy, crystals were considered in the same statical and structural light, but modern crystallograjDhers, having become more thoroughly acquainted with their physical properties and their actual formation, have abandoned the earlier views and have made their doctrines dependent on dynamics. The immediate object of this lecture is to show that, starting with Xewton's third law of motion, it is possible to preserve to chemistry all the advantages arising fiom structural teaching, with- out being obliged to build up molecules in solid and motionless figures, or to ascribe to atoms definite limited valencies, directions of cohesion, or affinities. The wide extent of the subject obliges me to treat only a small portion of it, namely of suhstitufions, without specially considering combinations and decomj)ositions, and, even then, limiting myself to the simplest examples, which, however, will throw open prospects embracing all the natural complexity of chemi- cal relations. For this reason, if it should prove possible to form groups similar, for example, to H* or CH^ as the remnants of mole- cules CH^ or C-H^ we shall not pause to consider them, because, as far as we know, they fall asunder into two parts, H- -f- H" oi' CH* -f H^, as soon as they are even temporarily formed, and are capable of separate existence, and therefore can take no part in the elemen- tary act of substitution. With respect to the simplest molecules which we shall select — that is to say, those of which the j^arts have no separatp existence, and therefore cannot appear in substitutions — • we shall consider them according to the periodic law, arranging them in direct dependence on the atomic weight of the elements. Thus, for example, the molecules of the simplest hydrogen compounds — HF hydrofluoric acid water ammonia methane correspond to elements the atomic weights of which decrease consecutively, F = 19, 0 = 16, N - 14, C = 12. Neither the arithmetical order (1, 2, 3, 4 atoms of hydrogen) nor the total information we possess respecting the elements will permit us to interpolate into this typical series one more additional element ; and therefore we have here, for hydrogen compounds, a natural base upon which are built up those simple chemical combinations which we take as typical. But even they are competent to unite with each other, as we see, for instance, in the property which hydrofluoric acid 1889.] on an aitemjJt to apj^If/ to Chemistri/, d'C. 513 has of forming a hydrate, that is of combining with water ; and the similar attribute of ammonia, resulting in the formation of a caustic alkali, NH^H-O, or XH^OH. Having made these indispensable preliminary observations, I may now attack the problem itself and attempt to explain the so-called structure, or rather construction of molecules, that is to say, their constitution and transformations without having recourse to the teaching of " structionists," but on Newton's dynamical principles. Of Newton's three laws of motion, only the third can be applied directly to chemical molecules when regarded as systems of atoms among which it must be supposed that there exist common influences or forces, and resulting compounded relative motions. Chemical reactions of every kind are undoubtedly accomplished by changes in these internal movements, respecting the nature of which nothing is known at present, but the existence of which, the mass of evidence collected in modern times, forces us to acknowledge as forming part of the common motion of the universe, and as a fact further established by the circumstance that chemical reactions are always characterised by changes of volume or the relations between the atoms or the molecules. Newton's third law, which is applicable to every system, declares that, " action is always associated with reaction, and is equal to it." The brevity and conciseness of this axiom was, however, qualified by Newton in a more expanded statement, " the action of bodies one upon another are always equal, and in opposite directions." This simple fact constitutes the point of departure for explaining dynamic equilibrium, that is to say, systems of con- servancy. It is capable of satisfying even the dualists, and of explaining, without additional assumptions, the preservation of those chemical types which Dumas, Laurent, and Gerhardt created unit types, and those views of atomic combinations which the structionists express by atomicity or the valency of the elements, and, in connec- tion with them, the various numbers of affinities. In reality if a system of atoms or a molecule be given, then in it, according to the third law of Newton, each portion of atoms acts on. the remaining portion in the same manner, and with the same force as the second set of atoms acts on the first. We infer directly from this considera- tion that both sets of atoms, forming a molecule, are not only equiva- lent with regard to themselves, as they must be according to Dalton's law, but also that they may, if united, replace each other. Let there be a molecule containing atoms ABC, it is clear that, according to Newton's law, the action of A on B C must be equal to the action of B C on A, and if the first action is directed on B C, then the second must be directed on A, and consequently then, where A can exist in dynamic equilibrium, B C may take its place and act in a like manner. In the same way the action of C is equal to the action of A B. In one word every two sets of atoms forming a molecule are equivalent to each other, and may take each other's place in other molecules, or, having the power of balancing each other, the atoms or their comple- 514 Lr. D. MendeUeff [May 31, ments are endowed with the power of replacing each other. Let us call this consequence of an evident axiom " the principle of substitu- tution," and let us apply it to those typical forms of hydrogen compounds, which we have already discussed, and which, on account of their simj)licity and regularity, have served as starting points of chemical argument long before the appearance of the doctrine of structure. In the type of hydrofluoric acid, HF, or in systems of double stars, are included a multitude of the simj^lest molecules. It will be sufficient for our purpose to recall a few : for example the molecules of chlorine, CP, and of hydrogen, H^, and hydrochloric acid, HCL, which is familiar to all in aqueous solution as spirit of salt, and which has many points of resemblance wdth HF, IIB2, HI. In these cases division into two parts can only be made in one way, and therefore the principle of substitution renders it probable that ex- changes between tbe chlorine and the hydrogen can take place, if they are competent to unite with each other. There was a time when no chemist would even admit the idea of any such action ; it was then thought that the power of combination indicated a polar difference of the molecules in combination, and this thought set aside all idea of the substitution of one component element by another. Thanks to the observations and experiments of Dumas and Laurent fifty years ago, such fallacies were dispelled, and in this manner, this same principle of substitution w^as exhibited. Chlorine and bromine acting on many hydrogen compounds, occupy immediately the place of their hydrogen, and the displaced hydrogen, with another atom of chlorine or bromine, forms hydrochloric acid or bromide of hydrogen. This takes place in all typical hydrogen compounds. Thus chlorine acts on this principle on gaseous hy- drogen— reaction, under the influeace of light, resulting in the forma- tion of hydrochloric acid. Chlorine acting on the alkalis, constituted similarly to water, and even on water itself — only, however, under the influence of light and only partially because of the unstability of HCIO — forms by this princijile bleaching salts, which are the same as the alkalis, but with their hydrogen replaced by chlorine. In ammonia and in methane, chlorine can also replace the hydrogen. From ammonia is formed in this manner the so-called chloride of nitrogen, NOP, which decomposes very readily with violent explosion on account of the evolved gases, and falls asunder as chlorine and nitrogen. Out of marsh gas, or methane, CPP, may be obtained con- secutively, by this method, every possible substitution, of which chloro- form, CHCP, is the best known, and chloro-carbonic acid, CCP the most instructive. But by virtue of the fact that chlorine and bromine act, in the manner shown, on the simplest typical hydrogen compounds, their action on the more complicated ones may be assumed to be the same. This can be easily demonstrated. The hydrogen of benzole, C^il^ reacts feebly under the influence of light on liquid bromine, but Gustavson has shown that the addition of the smallest quantity of 1889.] on an attempt to apply to Chemistry, d'c. 515 metallic aluminium causes energetic action, and the evolution of large volumes of bromide of hydrogen, If we pass on to the second typical hydrogen compound, that is to say water, its molecule, HOH, may be split up in two ways : either into an atom of hydrogen and a molecule of oxide of hydrogen, HO, or into oxygen, 0, and two atoms of hydrogen, H; and therefore, according to the principle of substitution, it is evident that one atom of hydrogen can exchange with oxide of hydrogen, HO, and two atoms of hydrogen, H, with one atom of oxygen, 0. Both these forms of substitution will constitute methods of oxidation, that is to say, of the entrance of oxygen into the com- pound— a reaction which is so common in nature as well as in the arts, taking place at the expense of the oxygen of the air or by the aid of various oxidising substances or bodies which part easily with their oxygen. There is no occasion to reckon uj) the unlimited number of cases of such oxidising reactions. It is sufficient to state that in the first of these oxygen is directly transferred, and the position, the chemical function, which hydrogen originally occupied is, after the substitution, occupied by the hydroxyl. Thus ammonia, NH^, yields hydroxylamine, NH-(OH), a substance which retains many of the jDroperties of ammonia. Methane and a number of other hydrocarbons yield, by substi- tution of the hydrogen by its oxide, methylic, CH^(OH), and other alcohols. The substitution of one atom of oxygen for two atoms of hydrogen is equally common with hydrogen compounds. By this means alcoholic liquids containing ethyl alcohol, or spirits of wine, C^H^(OH), are oxidised till they become vinegar or acetic acid, C^H^O(OH). In the same way caustic ammonia, or the combination of ammonia with water, NH^H'-O, or NH-^(OH), which contains a great deal of hydrogen, by oxidation exchanges four atoms of hydrogen for two atoms of oxygen, and become converted into nitric acid NO-^(OH). This process of conversion of ammonia salts into saltj)etre goes on in the fields every summer, and with especial raj^idity in tropical countries. The method by which this is accomplished, though complex, though involving the agency of all-permeating micro- organisms, is, in substance, the same as that by which alcohol is converted into acetic acid, or glycol, C-H'^(OH)'', into oxalic acid, if we view the process of oxidation in the light of the Newtonian principles. But while speaking of the application of the principle of substi- tution to water, we need not multiply instances, but must turn our attention to two special circumstances which are closely connected with the very mechanism of substitutions. In the first place, the replacement of two atoms of hydrogen by one atom of oxygen may take j^lace in two ways, because the hydrogen molecule is comj)osed of two atoms, and therefore, under the influence of oxygen, the molecule forming water may separate before the oxygen has time to take its place. It is for this reason that we find, during 516 Br, D. MendeUeff [May 31, the conversion of alcohol into acetic acid, that there is an interval during which is formed aldehyde, C^H^O, which, as its very name implies, is "alcohol dehydrogenaturo," or alcohol deprived of hydrogen. Hence aldehyde combined with hydrogen yields alcohol ; and united to oxygen, acetic acid. For the same reason there should be, and there actually are, intermediate products between ammonia and nitric acid, NO-(HO), containing either less hydrogen than ammonia, less oxygen than nitric acid, or -less water than caustic ammonia. Accordingly we find, among the products of the de-oxidisation of nitric acid and the oxidisation of ammonia, not only hydroxy lamine, but also nitrous oxide, nitrous and nitric anhydrides. Thus, the production of nitrous acid results from the removal of two atoms of hydrogen from caustic ammonia and the substitution of the oxygen for the hydi'ogen, NO (OH) ; or by the substitution, in ammonia, of three atoms of hydrogen by hydroxyl, N(OH)^ and by the removal of water; N(0HJ'-H20 = NO(OH). The ^peculiarities and properties of nitrous acid, as, for instance, its action on ammonia and its conversion, by oxidation, into nitric acid, are thus clearly revealed. On the other hand, in speaking of the principle of substitution as applied to water, it is necessary to observe that hydrogen and hydroxyl, H and OH, are not only competent to unite, but also to form combinations with themselves, and thus become H" and H-O^ ; and such are hydrogen and the peroxide thereof. In general, if a mole- cule AB exists, then molecules AA and BB can exist also. A direct reaction of this kind does not, however, take place in water, therefore undoubtedly, at the moment of formation hydrogen reacts on the peroxide of hydrogen, as we can show, at once, by experiment ; and further because the peroxide of hydrogen, H-0^, exliibits a structure containing a molecule of hydrogen, H-, and one of oxygen, 0^, either of which is capable of sei)arate existence. The fact, however, may now be taken as thoroughly established, that, at the moment of combustion of hydrogen or of the hydrogen compounds, peroxide of hydrogen is always formed, and not only so, but in all probability its formation invariably precedes the formation of water. This was to be expected as a consequence of the law of Avogadro and Gerhardt, which leads us to expect this sequence in the case of equal interactions of volumes of vapours and gases ; and in the peroxide of hydrogen we actually have such equal volumes of the elementary gases. The instability of peroxide of hydrogen — that is to say, the ease with which it decomposes into water and oxygen, even at the mere contact of porous bodies — accounts for the circumstance that it does not form a permanent product of combustion, and is not jDroduced during the decomposition of water. I may mention this additional consideration that, with respect to the peroxide of hj^drogen, we may look for its effecting still further substitutions of hydrogen by means of which we may expect to obtain still more highly oxidised water-compounds, such as H'O^ and H-'O*. These Schonbeiu and 1889.] on an attempt to ajpphj to Chemistrij, &c. 517 Bunsen have long been seeking, and Berth elot is investigating them at this moment. It is probable, however, that the reaction will stop at the last compoimcl, because we find that, in a number of cases, the addition of 4 atoms of oxygen seems to form a limit. Thus, OsO*, KC10^ KMuO*, K-SO^ Na^^PO^ and such like, represent the highest grades of oxidation.* As for the last 40 years, from the times of Berzelius, Dumas, Liebig, Gerhardt, Williamson, Frankland, Kolbe, Kekule, and Butlerow, most theoretical generalisations have centred round organic or carbon comjDOunds, so we will, for the sake of brevity, leave out the discussion of ammonia derivatives, notwithstanding their sim- plicity in respect to the doctrine of substitutions ; w^e will dwell more especially on its application to carbon compounds, starting from methane, CH*, as the simplest of the hydrocarbons, containing in its molecule one atom of carbon. According to the principles enume- rated we may derive from CH^ every combination of the form CH^X, CH^X^, CHX^, and CX'^, in which X is an element, or radical, equivalent to hydrogen, that is say, competent to take its place or to combine with it. Such are the chlorine substitutes mentioned already, such is wood-spirit, CH2(0H), in which X is represented by the residue of water, and such are numerous other carbon derivatives. If we continue, with the aid of hydroxyl, further substitutions of the hydrogen of methane we shall obtain successively CH-(OH)^, CH(OH)^, and C(013)-^. But if, in- proceeding thus, we bear in mind that CH-(OH)'^ contains two hydroxyls in the same form as peroxide of hydrogen, H-0" or (OH)'^, contains them — and moreover not only in one molecule, but together, attached to one and the same atom of carbon — so here we must look for the same decomposition as that which we find in peroxide of hydrogen, and accompanied also by the formation of water as an independently existing molecule ; * Because more than four atoms of hydrogen never unite with one atom of the elements, and because the hydrogen comj ounds (e. g. HCl, H-S, H^P, H^Si) always form their highest oxides with four atoms of oxygen, and as the highest forms of oxides (OSO^ RO^) also contain four of oxygen, and eight groups of the periodic system, corresponding to the highest basic oxides K-0, EO, R-0^, RO^, R-O^, RO^, R-0", and ROS imply the above relationship, and because of the nearest analogues among the elements— such as Mg, Zn, Cd, and Hg; or Cr, Mo, W and U ; or Si, Ge, Sn, and Pt ; or F, CI, Br, and J and so forth — not more than four are known, it seems to me that in these relationships there lies a deep interest and meaning with regard to chemical mechanics. But because, to my imagination, the idea of unity of design in Nature, either acting in complex celestial systems or among chemical molecules, is very attractive, especially because the atomic teaching at once acquires its true meaning, I will recall the following facts relating to the solar system. There are eight major planets, of which the four inner ones are not only separated from the four outer by aste- roids, but ditfer from them in many respects, as for example in the smallness of their diameters and their greater density. Saturn with his rmg has eight satellites, Jupiter and Uranus have each four. It is evident that in the solar systems also we meet with these higher numbers four and eight which appear in the combination of chemical molecules. 518 Br. D. Mendeleeff [May 31, therefore Cn2(0H)^ should yield, as it actually does, immediately water and the oxide of methylene, CH""0, which is methane with oxygen substituted for two atoms of hydrogen. Exactly in the same manner out of CH(OH)^ are fo/med water and formic acid, CHO(OH), and out of C(OII)^ is produced water and carbonic acid, or directly carbonic anhydride, CO'-, which will tlierefore be nothing else than methane with the double replacement of pairs of hydrogen by oxygen. As nothing leads to the supposition that the four atoms of hydrogen in methane differ one from the other, so it docs not matter by what means we obtain any one of the combinations indicated — they will be identical ; that is to say, there will be no case of actual isomerism, although there may easily be such cases of isomerism as have been distinguished by the term metamerism. Formic acid, for example, has two atoms of hydrogen, one attached to the carbon left from the methane, and the other attached to the oxygen which has entered in the form of hydroxyl, and if one of them be replaced by some substance X it is evident that we shall obtain bodies of the same composition, but of different construction, or of different orders of movement among the molecules, and therefore endowed with other properties and reactions. If X be methyl, CH^, that is to say, a group capable of rejdacing hydrogen because it is actually contained with hydrogen in methane itself, then by substi- tuting this group for the original hydrogen, we obtain acetic acid, CCH^O(OH), out of formic, and by substitution of the hydrogen in its oxide or hydroxyl we obtain methyl formiate, CHO(OCH^). These bodies differ so much from each other physically and chemically that, at first sight, it is hardly possible to admit that they contain the same atoms in identically the same proportions. Acetic acid, for example, boils at a higher temperature than water, and has a higher specific gravity than it, while its metamer, formo-methylic ether, is lighter than water, and boils at 30", that is to say, it evaporates very easily. Let us now turn to carbon compounds containing two atoms of carbon to the molecule, as in acetic acid, and proceed to evolve them from methane by the principle of substitution. This principle declares at once that methane can only be split up in the four following ways : — 1. Into a group CH^ equivalent with H. Let us call changes of this nature methylation. 2. Into a group CH- and H'-. We will call this order of substitutions methylenation. 3. Into CH and 11^, which commutations we will call acetylena- tion. 4. Into C and H"^, which may be called carbonisation. It is evident that hydrocarbon compounds containing two atoms of carbon, can only proceed from methane, CH*, which contains four atoms of hydrogen by the first three methods of substitution ; carbonising would yield free carbon if it could take place directly, and if the 1889.] on an attempt to apply to Chemistry, &c. 519 molecule of free carbon — which is in reality very complex, that is to say strongly polyatomic, as I have long since been proving by various means — could contain only C- like the molecules 0'-, H-, N-, and so on. By methylation we should evidently obtain from marsh gas, ethane, CE.^6W = C-H^. By methylenation, that is by substituting group CH- for H^, methane forms ethylene, CH-CH- = C-H-^. By acetylenation, that is by substituting three atoms of hydrogen, H^, in methane, by the remnant CH, we get acetylene CHCH = C-H^. If we have applied the principles of Newton correctly, there should not be any other hydrocarbons containing two atoms of carbon in the molecule. All these combinations have long been known, and in each of them we can not only produce those substitutions of which an example has been given in the case of methane, but also all the phases of other substitutions, as we shall find from a few more instances, by the aid of which I trust that I shall be able to show the great complexity of those derivatives which, on the principle of sub- stitution, can be obtained from each hydrocarbon. Let us content ourselves with the case of ethane, CH^CH^, and the substitution of the hydrogen by hydroxyl. The following are the possible changes. 1. CH^CH-(OH) : this is nothing more than spirit of wine, or ethyl alcohol, Q'-W{OK) or C-H^O. 2. CH'^(0H)CH2(0H) : this is the glycol of Wurtz, which has shed so much light on the history of alcohol. Its isomer may be CH3CH(0H)-, but as we have seen in the case of CH(OH)-, it decomposes giving off water, and forming aldehyde, CH^CHO, a body capable of yielding alcohol by uniting with hydrogen and of yielding acetic acid by uniting with oxygen. If glycol CH'(OH)CH'(OH) loses its water, it may be seen at once that it w^ill not now yield aldehyde, CH'^CHO, but its isomer, ^ , the oxide of ethylene. I have here indicated in a special manner the oxygen which has taken the place of two atoms of the hydrogen of ethane taken from different atoms of the carbon. 3. CH3C(OH)3 decomposed as CH(0H)3, forming water and acetic acid OB[^CO(OH). It is evident that this acid is nothing else than formic acid, CHO(OB[), with its hydrogen replaced by methyl. Without examining further the vast number of possible derivatives, I will direct your attention to the circumstance that in dissolving acetic acid in water we obtain the maximum contraction and the greatest viscosity when to the molecule CH"C0(OH) is added a molecule of water, which is the proj^ortion which would form the hydrate CH^C(OH)^. It is probable that the doubling of the mole- cule of acetic acid at temperatures approaching its boiling point has some connection with this power of uniting with one molecule of water. 4. CH2(OH)C(OH)3 is evidently alcoholic acid, and indeed this compound, after losing water, answers to glycolic acid, CH"^(OII)CO 520 Br. B. Mendelee^ [May 31, (OH). "Without investigating all the possible isomers, we will note only that the hydrate CH(OH)'-CH(OH)- has the same composition as CH-(OH)C(^OH)^, and although corresponding to glycol, and being a symmetrical substance, it becomes on part'ng with its water aldehyde of oxalic acid, or the glyoxal of Debus, CHOCHO. 5. CH(OH)-C( OH^), from the tendency of all the preceding, corresponds to glyoxylic acid, aldehyde acid, CHOC 0( OH), because the g"oup CO(OH), or carboxyl, enters into the compositions of organic acids, and the group CHO defines the aldehyde function. 6. C(OHPC(OH)^ through the loss of 2H-0 yields the bibasic oxalic acid C0( OH )C0^ OH), which generally crystallises with 2H'0, following thus the normal type of hydration characteristic of ethane.* Thus, by applying the principle of substitution, we can, in the simplest manner, derive not only every kind of hydrocarbon com- pound, such as the alcohols, the aldehyde alcohols, aldehydes, alcohol acids, and the acids, but also combinations analogous to hydrated crystals which usually are disregarded. But even those unsaturated substances, of which ethylene, CH-CH-, and acetylene, CHCH, are types, may be evolved with equal sim- plicity. ^Vith respect to the phenomena of isomerism, there are many possibilities among the hydrocarbon compounds containing two atoms of carbon, and without going into details it will be sufficient to indicate that the following formulae, though not identical, will be isomeric substantially among themselves : — CH'^CHX- and CH=^XCH-X, although both contain C=^H*X^ or CH-CX- and CHXCHX, although both contain C'-H-X-, if by X we indicate chlorine or generally an element capable of replacing one atom of hydrogen, or capable of uniting with it. To isomerism of this kind belongs the case of aldehyde and the oxide of ethylene, to which we have already referred, because both have the composition C-H^O. * One more isomer, CH^CH (OH), is possible, that is secondary vinyl alcohol, which ia related to ethylene. CH-CH-, but derived by the principle of substitution from CH*. Other isomers of the composition C-H*0, such, for example, as CHCH^ (OH), are impossible, because it would correspond to the hydrocarbon CHCH^ = C-H*. which is isomeric with ethylene, and it cannot be derived from metLane. If such an isomer existed, it would be derived from CH-, but such products are up to the present unknown. In such cases the insufficiency of the points of departure of the statical structural teaching is shown. It first admits constant atomicity and then rejects it, the facts serving to establish either one or the other view; and therefore, it seems to me, that we must come to the conclusion that the structural method of reasoning, having done a service to science, has outlived the age, and must be regenerated as, in their time, was the teaching of the electro-chemists, the radicalists, and the adherents of the doctrine of type:*. As we cannot now lean on the views above stated, it is time to abandon the structural theory. They will all be united in chemical mechanics, and the principle of substitution must be looked upon only as a preparation for the coming epoch in chemistry, where such cases as the isomerism of fumaric and maleic acids, when explained dynamically, as proposed by Le Bel and Van't Hoff, may yield points of departure. 1889.] on an attempt to apply to Chemistry, dr. 521 What I have said appears to me sufficient to show that the principle of substitution adequately explains the composition, the isomerism and all the diversity of combination of the hydrocarbons, and I shall limit the further development of these views to preparing a complete list of every possible hydrocarbon compound containing thi-ee atoms of carbon in the molecule. There are eight in all, of which only five are known at present.* Among those possible for C"H^ there should be two isomers, propylene and trimethylene, and they are both already known. For C"H^ there should be three isomers : allylene and allene are known, but the third has not yet been discovered ; and for C"H- there should be two isomers, though neither of them are known as yet. Their composition and structure is easily deduced from ethane, ethylene, and acetylene, by methylation, methylenation, by acetylenation and by carbonisation. 1. C^H* = CH^CH-CH^ out of CH^CHs by methylation. This hydrocarbon is named propane. 2. C^H^ = CH^CHCH- out of CH^CHs by methylenation. This substance is propvlene. 3. C^H^ = CH-CH-CH- out of CH^CH^ by methylenation. This substance is trimethylene. 4. C^H* = CH^CCH out of CH^CH^ by acetylenation or from CHOH bv methylation. This hvdrocarbon is named allylene. 5. C^H-^ = CHCH out of CH^CH^ by acetylenation, or from CWCW by methylenation, because CH-CH = CHCH. This body CH Cff is as yet unknown. 6. C^H^ = CH-CCH- out of CH-CH- by methylenation. This hydrocarbon is named allene, or iso-allylene. 7. C^H-^ = CHCH out of CH^H^ by symmetrical carbonisation, C or out of CH-CH- bv acetvlenation. This compound is unknown. 8. C-H- = C("' out of CH^CH^ by cai-bonisation, or out of CHCH CH^ by methylenation. This compound is unknown. If we bear in mind that for each hydrocarbon serving as a type in the above tables there are a number of corresponding derivatives, and that every comi)ound obtained may, by further methylation, methylenation, acetylenation, and carbonisation, produce new hydro- carbons, and these may be followed by a numerous suite of derivatives and an immense number of isomeric bodies, it is possible to under- stand the limitless number of carbon compounds, although they all * Conceding variable atomicity, the structurists must expect an incomparably larger number of isomers, and they cannot now decline to acknowledge the change of atomicity, were it only for the 'examples HgCl and HgCP, CO and CO-, PCP and PCP. ' 522 Dr. D. Mendeleeff [May 13, have the one substance, methane, for their origin. The number of substances is so enormous that it is no longer a question of enlarging the possibilities of discovery, but rather of finding some means of testing them, analogous to the well-known two which for a long time have served as gauges for all carbon compounds. I refer to the law of even numbers and to that of limits, the first enunciated by Gerhardt forty years ago, with respect to hydro- carbons, namely, that their molecules always contain an even number of atoms of hydrogen. But by the method which I have used of deriving all the hydrocarbons from methane, CH^, this law may be deduced as a direct consequence of the principle of substitutions. Accordingly, in methylation, CH^ takes the jDlace of H, and there- fore CH^ is added. In methylenation the number of atoms of hydrogen remains unchanged, and at each acetylenation it is reduced by two, and in carbonisation by four atoms, that is to say, an even number of atoms of hydrogen is always added or removed. And because the fundamental hydrocarbon, methane, CH"^, contains an even number of atoms of hydrogen, therefore all its derivative hydrocarbons will also contain even numbers of hydrogen, and this constitutes the law of even numbered parts. The principle of substitutions explains with equal sim})licity the conception of limiting compositions of hydrocarbons, C'W + -, which I derived, in 1861,* in an empirical manner from accumulated materials available at that time, and on the basis of the limits to combinations w^orked out by Dr. Frankland for other elements. Of all the various substitutions the highest proportion of hydi'ogen is yielded by methylation, because in that operation alone does the quantity of hydrogen increase ; therefore, taking metbane as a point of departure, if we imagine methylation effected {n — 1) times we obtain hydrocarbon compounds containing the highest quantities of hydrogen. It is evident that they will contain CH^ + (71 - 1) CH^ or C"H2''+2, because methylation leads to the addition of CH^ to the compound. It will thus be seen that by the principle of substitution — that is to say, by the third law of Newton — we are able to deduce, in the simplest manner, not only the individual composition, the isomerism, and relations of substances, but also the general laws which govern theii' most complex combinations, without having recourse either to statical constructions, to the definition of atomicities, to the exclusion of free affinities, or to the recognition of those single, double, or treble ties which are so indispensable to structurists in the explanation of the composition and construction of hydrocarbon compounds. And yet, by the application of the dynamic principles of Newton, we can * ' Essai dune theorie sur les limites des combinaisons organiques,' par D. Mendeleeff, 2/11 aout 1861, ' Bulletin de I'Acadenaie i. d. Sc. de St. Peters- bourf^,' t. V. 1889,] on an attempt to appli/ to Chemistrij, &c. 523 attain to that chie^ and fundamental object — the comprehension of isomerism in hydrocarbon compounds, and the forecasting of the existence of combinations as yet unknown, by which the ediace raised by structiu-al teaching is strengthened and supported. Besides, and I count this for a circumstance of special importance, the process which I advocate will make no diiference in those special cases which have been already so well worked out, such as, for example, the isomerism of the hydrocarbons and alcohols, even to the extent of not interfering with the nomenclature which has been adopted, and the structural system will retain all the glory of having worked up, in a thoroughly scientific manner, the store of information which Gerhardt had accumulated about the middle of the fifties, and the still higher glory of establishing the rational synthesis of organic substances. Nothing will be lost to the structural doctrine, except its statical origin ; and as soon as it will embrace the dynamic principles of Newton, and suffer itself to be guided by them, I believe that we shall attain, for chemistry, that unity of principle which is now wanting. Many an adept will be attracted to that brilliant and fascinating enterprise, the penetration into the unseen world of the kinetic rela- tions of atoms, to the study of which the last twenty-five years hare contributed so much labour and such high inventive faculties. D'Alembert found in mechanics, that if inertia be taken to repre- sent force, dynamic equations may be applied to statical questions which are thereby rendered more simple and more easily understood. The structural doctrine in chemistry has unconsciously followed the same course, and therefore its terms are easily adopted ; they may retain their present forms provided that a truly dynamical, that is to say, Newtonian meaning be ascribed to them. Before finishing my task and demonstrating the possibility of adapting structural doctrines to the dynamics of Newton, I consider it indispensable to touch on one question which naturally arises, and which I have heard discussed more than once. If bromine, the atom of which is eighty times heavier than that of hydrogen, takes the place of hydrogen, it would seem that the whole system of dynamic equilibrium must be destroyed. Without entering into the minute analysis of this question, I think it will be sufficient to examine it by the light of two well- known phenomena, one of which will be found in the department of chemistry, and the other in that of celestial mechanics, and both will serve to demonstrate the existence of that unity in the plan of creation, which is a consequence of the Newtonian doctrines. Experiments demonstrate that when a heavy element is substituted for a light one, in a chemical compound — an atom of magnesium in the oxide of that metal, for example, for mercury, the atom of which is 8i times heavier — the chief chemical characteristics or properties are generally though not always preserved. The substitution of silver for hydrogen, than which it is 108 times heavier, does not aifect all the properties of the substance, Vol. XII. (No. 83.) 2 n 524 Dr. D. Mendeleeff [May 31, though it does some. Therefore chemical substitutions of this kind, the substitution of light for heavy atoms, need not necessarily entail changes in the original equilibrium ; and this point is still further elucidated by the consideration that the periodic law indicates the de<^ree of influence of an increment of weight in the atom as affecting the possible equilibria, and also what degree of increase in the weight of the atoms reproduces some, though not all, the properties of the substance. This tendency to repetition, these periods, may be likened to those annual or diurnal periods with which we are so familiar on the earth. Days and years follow each other : but, as they do so, many things change ; and in like manner chemical evolutions, changes in the masses of the elements, permit of much remaining undisturbed, though many properties undergo alteration. The system is main- tained according to the laws of conservation in nature, but the motions are altered in consequence of the change of parts. Next, let us take an astronomical case, such for example as the earth and the moon, and let us imagine that the mass of the latter is constantly increasing. The question is, what will then occur ? The path of the moon in space is a wave-line similar to that which geometricians have named epicycloidal, or the locus of a point in a circle rolling round another circle. But in consequence of the influence of the moon, it is evident that the path of the earth itself cannot be a geometric ellipse, even supposing the sun to be im- movably fixed ; it must be an epicycloidal curve, though not very far removed from the true ellipse, that is to say, it will be impressed with but faint undulations. It is only the common centre of gravity of the earth and the moon which describes a true ellipse round the sun. If the moon were to increase, the relative undulations of the earth's path would increase in amplitude, those of the moon would also change, and when the mass of the moon had increased to an equality with that of the earth, the path would consist of epicycloidal curves crossing each other, and having opposite phases. But a similar relation exists between the sun and the earth because the former is also moving in space. We may apply these views to the# world of atoms, and suppose that, in their movements, when heavy ones take the place of those that are lighter, similar changes take place provided that the system or the molecule is preserved through- out the change. It seems probable that in the heavenly systems, during incalculable astronomical periods changes have taken place and are still going on similar to those which pass rapidly before our eyes during the chemical reaction of molecules and the progress of molecular me- chanics, may — we hope will — in course of time, permit us to explain those changes in the stellar world which have more than once been noticed by astronomers, and which are now so carefully studied. A coming Newton will discover the laws of these changes. Those laws, when applied to chemistry, may exhibit peculiarities, but these 1889.] on an attempt to apply to Chemistry, dc. 525 will certainly be mere variations on the grand harmonious theme which reigns in nature. The discovery of the laws which produce this harmony in chemical evolutions will only be possible, it seems to me, under the banner of Newtonian dynamics which have so long waved over the domains of mechanics, astronomy, and physics. In calling chemists to take their stand under its peaceful and catholic shadow I imagine that I am aiding in establishing that scientific union which the managers of the Royal Institution wish to effect, who have shown their desire to do so by the flattering invitation which has given me — a Russian — the opportunity of laying before the countrymen of Newton an attempt to apply to chemistry one of his immortal principles. I'D. M.] GENERAL MONTHLY MEETING, Monday, June 3, 1889. Sir James Crichton Browne, M.D. LL.D. F.R.S. Vice-President, in the Chair." Miss Beatrice Harvey, Reginald Ward, Esq. were elected Members of the Royal Institution. The Honorary Secretary reported the decease of Mr. Henry Pollock, Treasurer and Vice-President, on the 15th of May last. The following Resolution passed by the Managers at their Meeting this day was read : — Resolved, " It is with the deepest regret that the Managers have to record the loss of their Treasurer aud Vice-Fresideut, Mr. Henry FoUock, " Elected a Member of the Royal Institution thirty-five years ago, he has ever since shown the warmest interest in the prosperity of the Institution, and has devoted himself to its advancement in every way. Several years he Was a Manager, and for the last three years he has been our Treasurer, and in that capacity, has most materially benefited the Institution by his business aptitude and by his close attention to its afiairs. " Although during a period of some two years the state of his health has not permitted him to be present at our Meetings, he has nevertheless, for the greater part of that time, still attended to our interests, by going over the accounts at his own house, and by seeing, from time to time, the Secretary and Professor Dewar, when occasion has arisen for consultation upon any important matter. " The Managers feel that, in the loss of a colleague so very earnest for the welfare of the Institution ; so thoroughly able in the discharge of his duties ; and 2 N 2 526 General Monthly Meeting. [June 3) so kindly and courteous to all, tlie Institution has been deprived of one of its most proved and useful ^lembers." Besolved, " That the Honorary Secretary do transmit to Mrs. Henry Pollock a copy of the foregoing Kesolution, together with an expression of the deep sympathy entertained by the Managers with her in her great bereavement." The Special Thanks of the Members were returned for the following Donations to the Fund for the Promotion of Experimental Eesearch : — Mrs. J. Gibbs £10 10 Ludwig Mond, Esq 100 0 The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz : — Secretary of State for India — Eeport on Public Instruction in Bengal, 1887-8. fol. Academy of Natural Sciences, Philadelphia— Troceedmcrs, 1888, Part 2. 8vo. Agricidtiir'al Society of EnrjJand, Boijal— Journal, Vol. XXV. Part 1. Svo. 1889. Astronomical Society,' Bot/al — Monthly Notices, Vol. XLIX. No. 6. Svo. 1889. Bankers, Institute o/— Journal, Vol. X. Part 5. 8vo. 1889. Berlin Bibliographic 0^^/ct^— Bibliographisch-kritischer Anzeiger fiir romauische Sprachen und Literaturen, Band I. 8vo. 1889. Bolton, H. Carrington, Esq. Ph.D. {the ^M^/ior)— Ancient Method of Filtration. Svo. 1880. Catalogue of Chemical Periodicals. Svo. 1885. Abstracts of Papers (New York Academy of Sciences). Svo. 1888. British Architects, Boyal Institute o/— Proceedings, 1888-9, Nos. 13, 14. 4to. Chemical Industry, Society o/^Journal, Vol. VIII. No. 4. Svo. 1889. Chemical Society-~J ournal for INIay 1889. Svo. Costa Pica Iegatio7i—C-A&e and Arguments of the Republic of Nicaragua. Svo. 1887-8. Cracovie, L' Academic des /S^ciences— Bulletin, 1889, No. 4. Svo. Editors — American Journal of Science for May, 1889. Svo. Analvst for Mav. 1889. Svo. Atheufeum for Mav, 1889. 4to. Chemical News for JNIay, 1889. 4to. Chemist and Druggist for May, 1889. Svo. Electrical Engineer for May, 1889. fol. Engineer for Mav, 1889. fol. Engineering for May, 1889. fol. Horological Journal for May, 1889. Svo. Industries for Mav, 1889. fol. Iron for May, 1889. 4to. Murrav's Magazine for May, 1889. Svo. Nature for May, 1889. 4to. Photographic News for May, 1889. Svo. Revue" Scientifique for May, 1889. 4to. Telegraphic Journal for Mav. 1889. Svo. Zoophilist for May, 1889. 4to. Electrical Engineers, Institution o/— Journal, No. 79. Svo. 1889. FranMin Institute — Journal, No. 761. Svo. 1889. Geographical Society, iJo?/aZ— Proceedings, New Series, Vol. XL No. 5. Svo. 1889. 1889.] General Monthly Meeting. 527 Geological Institute, Imperial, Vienna — Verhandlungen, 18S9, No. 4-6. 8vo. Geological Society — Quarterly Journal, No. 178. 8vo. 1889. Hall, Rev. A. J. [the Author') — Grammar of the Kwagintl Language (Trans. Roy. Soc. Canada, Vol. VI. 1888). 4to. 1889. Harlem, Societe HoUandaise des Sciences — Archives Neerlandaises, Tctoe XXIII. Liv. 2. 8vo. 1889. Linnean Society — Journal, Nos. 132, 173. 8vo. 1889. Liverpool Polytechnic Society — Journal, Nos. 50, 51. 8vo. 1887-8. Madrid Royal Academy of Sciences — Anuario, 1889. 8vo. Major, Frederick, Esq. (the Author) — Spacial and Atomic Energy, Part 1. 8vo. 1889. Manchester Geological /Soeiefy— Transactions, Vol. XX. Parts 5-8. 8vo. 1889. Meteorological O/race— Hourly Pteadings, 1886, Part 3. 4to. 1889. Report of the Meteorological Council, Sept. 1888. 8vo. Weekly Weather Reports, Nos. 1-21. 4to. 1889. Middlesex Hospital— Reports, 1887. Svo. 1888. National Life-Boat Institution, Royal — Annual Report, 1889. 8vo. Odontological Society of Great Britain — Transactions, Vol. XXI. Nos. 6, 7. New Series. 8vo. 1888. Pharmaceutical Society of Great Britain — Journal, May, 1889. Svo. Photograpjhic Society — Journal, Vol. XIII. No. 5. Svo. 1889. Richards, Admiral Sir G. H. K.C.B. F.R.S. &c. (the Conservator)— Pie-port on the Navigation of the River Mersey, 1888. Svo. 1889. Rio de Janeiro Observatory — Revista, No. 3. Svo. 1889. Royal Society of London — Proceedings, No. 278. Svo. 1889. Society of Architects — Proceedings, Vol. I. No. 11. Svo. 1889. Society o/ ^7fs— Journal for May, 1889. Svo. St. Petersbourg Academic Imp&iales des Sciences — Memoires, Tome XXXVI. Nos. 12, 13. 4to. 1888. Bulletin, Tome XXXIII. No. 1. 4to. 1889. United Service Institution, Royal — Journal, No. 147. Svo. 1889. University of London — Calendar, 1889-90. Svo. Vereins zur Beforderung des Gewerhjleises in Preussen — Verhandlungen, 1889 : Heft, 4. 4to. Vernon- Harcourt, L. F. Esq. 3I.A. (the Author) — The Principles of training Rivers through Tidal Estuaries (Proc. Roy. Soc. 45). Svo. 1889. Victoria Institute — Transactions, No. 88. Svo. 1889. Wright & Co. Messrs. John (the Publishers)— Liectuxes on Massage and Electricity. By T. S. Dowse. Svo. 1889. 528 Mr. Archibald Geikie [June 7, WEEKLY EVENING MEETING, Friday, June 7, 1889. Colonel James A. Grant, C.B. C.S.I. F.K.S. Vice-President, in the Cbair. Archibald Geikie, Esq. LL.D. F.R.S. DIRECTOK-GEXERAL OF THE GEOLOGICAL SURVET OF THE UNITED KINGDOM. Beceni BesearcJies into the Origin and Age of the Highlands of Scotland and the West of Ireland. The records of geological history, like those of the human race, become more fragmentary and illegible, the farther back we trace them into the past. While the younger rocks of the earth's crust have been made to yield a more or less connected story of geographical and biological evolution, the oldest rocks have till comparatively lately been neglected, or have been tacitly left to mere speculation and conjecture. Only within the last few years have these ancient formations been seriously and sedulously attacked by scientific methods of inquiry. Though the progress of investigation has necessarily been slow, a steady advance in knowledge can be chronicled. There is a curious fascination in this dei)artment of geology. These venerable rocks reveal to us the oldest known part of the outer shell of our planet. The palimpsest of the earth's surface has been written over again and again during the long ages of geological history ; but down among these bottom-rocks we reach the earliest recognisable inscriptions, and come as near towards the beginning of things as geological evidence by itself is ever likely to lead us. These records carry us back to a time anterior to that of the oldest fossiliferous formations, possibly to an ej)Och that pre- ceded the appearance of vegetable or animal life on the globe. They reveal to us the very foundations of the earth's crust, on which all other known rocks rest, and out of the waste of which the greater part of these rocks has been formed. Within the last ten years, after prolonged misconception and neglect, the most ancient rocks of the British Isles have come to occupy a foremost place among the researches of the geologists of this country. The tracts where they are now exposed to view, often among the wildest mountains, or " placed far amid the melancholy main," have become favourite geological hunting grounds, and have furnished a notable amount of material for those disputes and com- bats which seem to form a necessary element in geological progress. Avoiding, as far as possible, matters of controversy, I propose this evening to offer a brief outline of the actual state of knowledge, up to the present time, of the history of those ancient crystalline masses 1889.] on the HigJdands of Scotland and the West of Ireland. 529 of whicli onr nortli-western mountains are composed.* The story is a somewhat involved and complicated one. But its main points may perhaps be conveniently grasped, if we bear in mind that they naturally group themselves into four sections ; 1st, the Archaean period ; 2nd, the Cambrian period ; 8rd, the Lower Silurian period ; 4th, the period of the younger Schists. Let me at the outset remark that in the investigation of these early ages of geological history we enjoy in this country a special advantage. The British Isles stand on the oceanic border of a great continental region. They are therefore placed along that critical belt where not only have terrestrial disturbances been especially numerous and violent from the earliest geological times, but where an oscillation U23ward or downward of a few hundred feet has sufficed to make all the difference between land and sea. In the heart of a continent, as, for example, over the vast plains of Russia, long cycles of geological time have passed without serious dis- turbance of any kind. To this day some of the ancient Palaeozoic sediments in that region, for hundreds of square miles in extent, lie as level as when they were deposited on the sea-floor. They have been uplifted bodily into land, but still remain little more than mere hardened mud and sand. In Western Europe, on the other hand, where from the remotest geological antiquity the oscillations and dislocations have been innumerable, every successive continental uplift has recorded itself in some crum'pling or fracture of the rocks. Hence in the geological map of that region the various formations form a pattern of exceeding complexity, while in the maps of Eastern Eurojje each of them covers a broad unbroken expanse. I. The Arch^an Period. The oldest known rocks of Europe, now generally termed Archaean, are well exposed along the north-western borders of the continental area from the extreme north of Scandinavia, by the west coast of Scotland, to Gal way Bay in the west of Ireland, a total distance of some 1600 miles. They give rise to topographical features which, where fully developed, strongly distinguish them from all younger formations. Nowhere else can such extraordinary un- evenness of surface be found. Knobs, hummocks, and ridges of bare or almost bare rock, separated by narrow gullies or by wider winding valleys, roughen the ground in every direction. In the hollows lie innumerable tarns and lakes, or flat tracts of bog where lakes once were. In some districts, indeed, there is as much water as land in a given number of square miles. On a large scale, this type of scenery is perhaps best displayed in Finland ; on a small scale, it is repeated * It would be obviously out of place to iuclude here references to the voluminous literature of the subject. A condensed summary will be found in the Report by the officers of the Geological Survey, ' Quart. Journ. Geol. Soc' vol. xliv. 1888. 530 Mr. Archibald Geikic [Jiiuo 7, all through the chtiiu of the outer Hebrides, as well as on the Archasau areas of the mainhmd. The most southerly points in Scotland where it can be recognised are the island of iona and the Eoss of Mull. It reappears, however, far to the south in Ireland ; standing out in the bold cliffs from Erris Head to Achill Island in the west of Mayo, and finally covering an area of more than 500 square miles in south-western Gal way. In this last named district, as Professor Hull has shown, so comj)letely are the scenic features of the north-west of Scotland reproduced, down even to the minutest details, that the geologist, even before he stands on the rocks, has no difficulty in deciding that they can only be Archaean. What, then, are these most ancient rocks of north-western Europe, and what has been their history ? Unfortunately the answer to these questions cannot be succinctly and definitely given. Owing to the antiquity of the masses, and the prolonged series of geological revolu- tions which they have undergone, their original characters have been somewhat effaced. In those areas where they have been least altered, and where, therefore, they approach nearest to their primitive structure, they have been found by my colleagues of the Geological Survey to be crystalline rocks, such as gabbros, diorites, and other highly basic comjiounds. These occur in zones or bosses surrounded by and passing into rocks which have acquired the peculiarly banded struc- ture characteristic of gneiss. That these various rocks were eruptive, that is, that they originally formed portions of igneous material that rose in a molten or plastic condition from below, can hardly be doubted. They remind us of the deeiD-seated portions of some of the eruptive bosses so abundantly intruded into the crust of the earth, and now so ^plentifully exposed at the surface after prolonged denudation. Like these, they show a rudely striped or banded arrangement suggestive of the planes of movement or flow- structure seen in consolidated igneous material. They have probably resulted from successive protrusions of eruptive rocks at some depth within the crust of the earth. Nowhere, however, in the region to which I am referring has any trace of superficial eruption yet been detected. There are no true volcanic ejections, nor any evidence that the rocks, though certainly of eruptive origin, were ever connected with the ordinary explosive operations of volcanic vents. Not only so, but after the most careful search from Sutherland to Gal way not a vestige have we yet found of any unquestionable sedimentary material. There are no con- glomerates, no sandstones, no shales ; nor even any materials that might be supposed to rej^resent these in a metamoriDhosed condition. Of the actual surface of the earth these Archaean rocks afford no recognisable trace. They obviously did not form the su^Derficial layer themselves. They must have lain deep under a cover of other material, under which they acquired their crystalline structure, and by the subsequent removal of which they have been exposed to the light. 1889.] on the Highlands of Scotland and the West of Ireland. 531 One of the most iniin'essive features of our receirt researches among these rocks is the evidence of the magnitude of the interval of time between their original protrusion and the formation of the next group of rocks overlying them. Of the many breaks in the geological record, none is more complete than this. We pass at one step from Archaean rocks, dating no doubt from an early stage in the consoli- dation of the crust of the planet, to the gravelly and sandy deposits of an inland sea, which already present all the familiar characters of tlie sedimentary accumulations of later geological time. Some of the more prominent events in this protracted interval may be more or less clearly discerned ; others can only be dimly conjectured. Arranging in chronological order the more important which have lately been recognised by the Geological Survey, I would direct your attention to four main episodes in the Archsean history of our north-western Highlands.* In the first place, the crust of the earth over that region was thrown into a series of low arches or folds, the axes of which ran in a general north-east and south-west direction. Its component rocks were crushed and sheared, so as to acquire the banded and crumjDled structure of typical gneiss. Perhaps we may trace to these primeval terrestrial movements the first shaping of the European continent, which certainly has grown from north to south. At all events, it is interesting to note that the undulations into which the rocks were thrown took that north-easterly trend ^'hich is still so marked in the long belt of crystalline schists from the North Cape all the way to the west of Ireland. In the second place after these early disturbances, and probably long after them, a remarkable series of manifestations of plutonic energy occurred. The region extending from the north-west of Scotland to the west of Ireland was convulsed by the production of innumerable dislocations in the solid terrestrial crusty having a general west-north-west direction. Up these gaping rents molten basic lava rose from some subterranean reservoir, and solidified in broad dykes of black basalt. Some of these dykes can be traced for ten or twelve miles till they run out to sea at the one end and pass under younger overlying formations at the other. Yet again at a somewhat later period another series of fissures was opened slightly oblique to the direction of the first, and in these still more basic lava formed a second series of dykes trending nearly east and west. Nor was this all, for there followed a third period of convulsion which gave birth to a series of huge dykes of granite. Whether or not any of the eruptive material that filled these suc- cessive fissures ever rose to the surface and flowed out there, or gave rise to the explosive phenomena of true volcanic vents cannot be certainly afiirmed. But an interesting piece of evidence points to the '^ Those who wish fuller details on this subject will find them in the Survey Report already quoted. 532 Mr. Archibald Geikie [June 7, probability that such a connection with the surface was really esta- blished. In some of the conglomerates of the next succeeding group (Cambrian or Torridon sandstones), there occur fragments of highly vesicular lavas, which show that at some time previous to the deposit of these coarse sediments, active volcanic vents existed somewhere in the region of the north-west of Scotland. As yet, however, no trace has been discovered of any of the lava-streams which flowed out at the surface. Although volcanic energy has long been quiescent over the British Isles, probably no area in Europe exhibits within so limited a space so long and varied a record of volcanic eruptions. There is, therefore, a peculiar interest about these traces of the ancient volcanoes which in Archaean time rose along the Atlantic border in the north-west of Scotland, for they stand at the very be- ginning of that long history. Moreover, so far as we can interpret their remains, they seem in a curious way to have anticipated the characteristics of the last great volcanic episode in Britain — that to which we owe the Tertiary basaltic j)lateaux of Antrim and the Inner Hebrides. In both cases, the distinguishing feature was the Assuring of the terrestrial crust and the uprise of basic lava in the rents, with the consequent production of innumerable j^arallel dykes trending in a general north-westerly direction. In the third place, after the production of the basic dykes, there came another prolonged interval, during which a series of remarkable terrestrial disturbances affected the north-west of Scotland. The crust of the earth in that part of Europe was once more dislocated by innumerable fissures, produced probably at successive epochs of paroxysm, for they can be grouped into three distinct series. Of these, one runs approximately parallel with the north-west dykes, the second trends east and west, and the third runs north-east and south- west, or north and south. So far as yet discovered, no lava of any kind welled upwards into these fissures. They are ruptures, but not dykes. They were accompanied, however, by the manifestation of another form of terrestrial energy, the geological efficacy of which has only recently been recognised. The lines of vertical fracture became also lines of horizontal or oblique movement during the vast strain of terrestrial contraction. One side was driven past the other side, and with such irresistible force that the rocks for some distance on either side were dragged into the line of movement, crushed down, and forced to assume a new crystalline arrangement of their materials. The basalt dykes, reduced sometimes from a width of 50 or GO yards to only four feet or less, were changed into diorites, and where the shearing was greatest, into hornblende-schists. The gneiss, in like manner, was thrown into sharp folds, and had a newer foliation developed in it parallel with the new planes of movement. In the fourth place, during the prolonged succession of changes which I have thus briefly summarised, there must have been in pro- gress a continuous denudation of the surface of the Archaean laud in 1889.J on the Highlands of Scotland and the West of Ireland. 538 the north-west of Europe. Doubtless, each of the subterranean dis- turbances more or less affected the surface. The land was by degrees ridged up above the sea, and its height and breadth were j^robably from time to time increased by local uplifts accompanying the disturbances. But as soon as the land aj)peared, it began to be attacked by the waves, the air, rain, and running water. Terrestrial convulsions were intermittent, but superficial waste continued uninter- rupted. Whatever may have been the character of its topography, the first formed land, as soon as it rose, became a prey to the denuding forces, and had its original surface gradually stripped off. We have no means of telling how great a thickness of material was in this manner removed from the land before the time of the next geo- logical period, nor for how vast a time this slow process of denuda- tion went on. All that we can now discover is a series of detached fragments of the surface of this primeval Europe, which have been preserved by being buried under the pile of material formed out of the waste of the Archaean rocks. From these fragments we learn that the rocks had been enormously denuded so as to lay bare to the surface some of their deep-seated parts, the land shaped out of them having been carved into dome-shaped hills and basin-like hollows, not very different from those which are so characteristic of the Archaean tracts to-day. II. The Cambrian Period. We now reach the base of the stratified formations of the British Isles, and enter upon a series of records which deal not with subter- ranean but with superficial changes, and in which the earliest geographical conditions of our area are more or less fully chronicled. These records consist of a pile of dull-red sandstones, conglomerates, and breccias, with grey, green, and black mudstones, marls and shales, attaining a maximum thickness of perhaps 10,000 feet. This great accumulation, chiefly of coarse sediment, was derived from the w^aste of the Archaean land. The pebbles in its conglomerates are fragments of that land, and enable us to form some conjecture as to the nature of the materials that composed its surface. An examina- tion of these pebbles brings to light the important fact that besides the detritus of the gneiss and other Archaean rocks which can now be seen in situ, the conglomerates are made up of materials derived from some still older sedimentary formations which have entirely disappeared from our area. These included such rocks as quartzite, greywacke, shale, and limestone, besides abundant pieces from the lavas, which I have already referred to as having probably been erupted to the surface in pre-Cambrian time. The destruction of these intervening deposits, and the chance discovery that they once existed because fragments of them have been found in later con- glomerates, serve to impress upon us the imperfection of the Geological Record and the vastness of the intervals of time which may sometimes separate two successive groups of rock. 531 Mr. Arcliibald GeiJcie [June 7, The thick mass of red sandstone and conglomerate, which rests directly on the Archaean gneiss, forms some of the most singular scenery in the north-west of Scotland. Owing to vast denudation, which began before the next gi'oup of strata was deposited, it has been worn down into isolated mountains, which rise like a chain of colossal pyramids along the western shores of Sutherland and Eoss. The almost level lines of stratification give to these eminences a look of architectural symmetry, in striking contrast with the more tumul- tuous aspect of the other rocks of the region, while theii* red tone of colour marks them out boldly from the wastes of grey gneiss below and the crags of white quartzite beyond. From the far northern cliffs of Sutherland these massive red sandstones can be followed almost continuously to the southern headlands of Skye. They reaj^pear in great force in the island of Eum, beyond which they are not certainly traceable. A group of highly altered grits and schists, seen under the great basaltic plateau of Gribuu, on the west side of the island of Mull, may mark their extreme southerly limits.* The red sandstones certainly do not come so far south as lona, and not a trace of them has been met with in Ireland. They extend westwards across the Minch, for a small portion of them skirts the eastern shore of the Long Island. How far they may have stretched eastward cannot now be determined, for their limits in that direction have been obscured or effaced by the extraordinary series of gigantic earth- movements to be afterwards referred to. There can be little doubt, however, that they did not reach the district east of the line of the Great Glen, though they not improbably lay in thick mass over much of the country to the west of that valley. We cannot now trace the original limits of these red rocks, yet we can hardly doubt that they never covered an area at all comparable in extent to that of the rocks below and above them. They appear, indeed, to have been accumulated in one or more basins, shut off from free communication with the open sea, where the deposition of ferru- ginous precipitates among the ordinary mechanical sediment could go on during the deposition of many thousand feet of rock. Such con- ditions of sedimentation were not very favourable to the existence of life in the waters of these enclosed basins. Nevertheless, that the waters were not entirely lifeless is shown by the discovery of organic remains on two widely separated horizons among the sandstones. These remains occur in grey and dark shales, the colour and compo- sition of which suggest a temporary influx of water from without and the cessation for a time of the deposition of the iron-oxide. At the lower horizon the fossils consist of calcareous rods, the organic grade of which is still in dispute ; at the higher they include some * My attention was called to these rocks by the Dake of Argyll, who himself suggested their jwssible Cambrian age. I visited them this spring, and found them to be greatly metamorphosed. They do not appear in lona, where the base of the sedimentary series is found resting on the Archsean gneiss. 1889.] on the Highlands of Scotland and the West of Ireland. 635 doubtful impressions and the casts of worms. The fossiliferous bands are to be more thoroughly searched this summer, and it is hoped that something more determinable may be obtained from them. Nevertheless, indistinct though these relics undoubtedly are, they may claim the interest which arises from their being at present the very oldest traces of organised existence yet found within our islands. Murchison classed the red sandstones of western Sutherland and Eoss as " Cambrian," inasmuch as he found them to underlie unconformably strata containing what he believed to be Lower Silurian fossils. It is not improbable, however, that they belong to an older time than any of the Cambrian rocks of "Wales. That the red sandstones of the north-west of Scotland were laid down in shallow water seems to be clearly indicated by their current- bedding and ripple-marks, as well as by the occurrence of bands of conglomerate among them on many successive horizons. Yet they retain these characters throughout a depth of some 10,000 feet. We can walk over their edges and count every successive stratum for a thickness of more than 300U feet along the sides of a single mountain. How, then, could such a continuous mass of shallow-water deposits be accumulated? I am not sure that any wholly satisfactory answer can be given to this question, which is one that arises in the investi- gation of various epochs of geological history. That the basins must have been due to local subsidence can hardly be doubted. We may suppose that this downward movement continued at the same time that the ridges which bounded the hollows continued to be forced upward. New shore-lines would thus be brought to the level of the water, and coarse shingle might be swept down upon pre- viously dej)0sited fine sediment. If occasionally the barrier between the basins and the open sea were partially submerged, the muddy ferruginous water of the enclosed tracts might be cleared out and the denizens of the sea might for a time enter them. Possibly the grey and dark shales may mark these irrujDtions of the ocean. That similar conditions of geography prevailed at that period in the extreme north-west of Europe is indicated by the fact that in Norway a group of red sandstones and conglomerates known as the " Sparagmite rocks " is interposed between the Archaean gneiss and the oldest of the fossiliferous formations. In these Scandinavian rocks we probably see traces of the extension of similar enclosed water-basins along the eastern border of the primeval Atlantic Ocean northwards among the hollows of the Archaean land. Before the next great geological period these basins had been entirely eflaced, and the geography of the region had wholly changed. This transformation is probably traceable to two causes. First, the terrestrial movements which led to the formation and continuance of the basins may in the end have caused their extinction by raising them into land, and possibly at the same time by folding and Assuring their accumulated deposits. Secondly, as soon as these deposits, whether split open or not, were exposed to the atmosphere they would 536 Mr. Archibald GeiMe [June 7, begin to be worn down. That erosion took jilace during a pro- longed period, and to a vast extent, is shown by the fact that in some places the thick cake of sandstone was hollowed out down to the Archsean platform below it before the next succeeding formations were deposited. Here again we are presented with a striking example of the imperfection of the Geological Kecord. III. The Silurian Period. After the long interval of time represented by the elevation of the red sandstones into dry land, and their entire removal from some places by denudation, the north-west of Scotland, and probably a large tract lying around it, sank under the sea. The depression seems to have been slow and gradual, and to have continued until the site of the Cambrian basins and of the surrounding region was covered with a considerable depth of clear open sea-water. The records of this subsidence are contained in a series of strata having a total thickness of somewhere about 2000 feet, and divisible into two chief groups — a Lower, composed of quartzitcs, grits, and thin con- glomerate, about 500 feet in total depth, and an Upper, consisting almost wholly of limestone. Perhaps the most striking feature in this series of stratified rocks is the abundance of their organic remains. The quartzites are crowded with the tubes formed by sea-worms when the material existed as soft white sand on the sea-bottom. The lime- stones are made uj) of the remains of calcareous organisms, among which the most conspicuous that now remain are chambered shells and gasteropods. Throughout these limestones worm-casts are present almost everywhere, and in such abundance as to show, as Mr. Peach has pointed out, that " nearly every particle of the calcareous mud must have passed through the intestines of worms." A large collec- tion of fossils has been made by the Geological Survey from these limestones, which, though not yet specifically determined, amply con- firm the original generalisation of Salter, made more than thirty years ago, that the aspect or facies of organic remains in the lime- stones of the north-west of Scotland resembles that of the older parts of the Lower Silurian formations of Canada rather than that of the corresponding rocks in Wales. So marked is the resemblance to the American type as to indicate that some shore-line must once have stretched across the North Atlantic, in order to afibrd a platform for the free migration of marine life between the two areas. The contrast with the Welsh type has been explained by the probable existence of some barrier that separated the sea-bed over the north-west of Scotland from that of southern Scotland, England, and Wales. That such a barrier existed is tolerably certain, and I shall presently refer to some indications of its probable position. At the same time it may be open to question whether the Durness limestones can be properly correlated as homotaxial equivalents of any Lower Silurian rocks in Wales. My own impression is that they may be older than the 1889.] on the Higldands of Scotland and the West of Ireland. 537 oldest Arenig rocks, and may be equivalent to some part of the "Primordial Silurian" or Cambrian series. This, however, is a question that must remain unsettled until a thorough critical exami- nation of the fossils has been completed. The area within which these Silurian quartzites and limestones can be certainly recognised, forms a narrow belt extending for about 110 miles along the north-west coast of Scotland, from the northern coast of Sutherland to the south of the island of Skye. Throughout that extent of ground the rocks exhibit remarkable persistence in the character and thickness of their several subdivisions, whence the inference may legitimately be drawn that the area within which they are now visible forms but a small part of the region over which they were originally deposited. It was claimed by Murchison, and generally conceded by geologists, that the quartzites and limestones of the north-w^est pass upward into a younger series of schists, representing metamorphosed sedimentary rocks. This order of succession appeared to be established by the evidence of many clear natural sections along the whole tract from Durness to Skye. It was first adopted and afterwards opposed by Nicol, who in his later papers maintained that the supposed younger schists were merely the old or Archaean gneiss brought up again by great faults, and pushed over the younger formations. But he failed to account for the striking difference in petrographical character between the old gneiss and the younger schists, and for the remark- able coincidence between the general dip of the latter and that of the Silurian stratified rocks on which they seemed to rest conformably. During the last ten years various geologists have renewed the investi- gation of the question, among whom I may specially mention Dr. Hicks, Professor Bouney, Dr. Callaw' ay, Professor Lapworth, and the members of the Geological Survey, particularly Messrs. Peach, Home, and Clough. The result of their labours has been, in the first place, the discovery of one of the most complicated pieces of geological structure at present known in any country ; in the second place, the abandon- ment of all further controversy, and the attainment of complete harmony regarding the order of geological succession in the north- west Highlands. Murchison's view that there is a regular upward passage from the quartzites and limestones into the upper schists is proved to be erroneous, while Nicol's contention that the old gneiss is brought up again above the Silurian rocks is found to be so far correct. But the structure is now seen to be infinitely more com23lex than Nicol imagined, while, on the other hand, Murchison's belief that the younger schists were evidence of a gigantic metamorphism later than Lower Silurian time is undoubtedly true, though in a sense very different from that in which he looked at the question. Nowhere in the north-west Highlands can any rock be seen resting in its original and natural position above the limestones. The highest limestone of Durness is the youngest rock of that region about the 538 Mr. Archibald Geikie [June 7, geological positiou of which there is any certainty. At present we know absolutely nothing of other sedimentary strata which followed that limestone. That such strata continued to be deposited is certain, for the changes which the quartzites and limestones have undergone could not have taken place save under the pressure of a thick mass of overlying material. But this superincumbent mass has been entirely obliterated in the extraordinary series of terrestrial movements which I have now to describe. IV. The Pekiod of the Younger Schists. Without entering into details, which are only intelligible with the help of a large map and sections, and even with this aid involve much disquisition of a technical kind, I may briefly say that after the deposition of the limestone and of the missing strata, whatever these may have been, which covered them, the whole region was convulsed by a series of disturbances, to which there has since been no parallel within our borders. By a series of intermittent movements the terrestrial crust, for thousands of feet downward, over the north-west Highlands, was fissured and i^ushed bodily westward. The various geological formations of that district — Archaean, Cambrian, and Silurian — were disrui^ted and driven over each other. Thus masses of rock, not more than a few hundred feet thick, were jiilcd up so as to appear multiplied tenfold. The youngest strata were doubled under the oldest, and large slices of the ancient Archaean gneiss were made to rest on the Silurian limestones. Fortunately the strongly marked characters of the different members of the Silurian series, the striking contrast between them and the Cambrian sandstones and Archasan gneiss, and the manner in which all these rocks are now laid bare on coast cliffs and rugged hill-sides, have rendered possible the task of unravelling this laby- rinthine structure. The large maps, on the scale of 6 inches to a mile, on which this structure has been worked out by the Geological Survey, are by far the most complicated which the Survey has yet produced ; indeed, I am not aware that such mapping has ever before been attempted. — [Some specimens of these maps were exhibited.] On exjjosed rock-faces we see a thin group of strata repeated again and again by small reversed faults, the lower beds being made to rest on the higher till they occupy a great breadth of ground, and appear of considerable thickness. Further examination will generally show that they have been all pushed westwards, and that their trun- cated under ends rest upon a platform of undisturbed ruck along which they have travelled. We may further observe them to be abruptly cut off at a higher level by a sharp line, on which perhaps stands another series of piled-up beds. This piling ujd and trunca- tion of the rocks is followed by a still more gigantic disjDlacement. Lower and lower portions of the geological series have been torn u]) and thrust westward until at last the ArchsGan platform has given 1889.] on the Highlands of Scotland arid the West of Ireland. 539 way, and masses of it, many hundreds of feet in thickness and many miles in length, have been driven over the younger formations. The horizontal distance to which this removal has reached can sometimes be shown to have amounted to at least ten miles ; perhaps it may have been sometimes even greater. In studying this complicated system of dislocations we soon meet with evidence that the movements were not all effected at one time, but that on the contrary they took place at intervals, the earlier being disrupted by the later. The lines of maximum thrust override those of lesser size, and the most easterly of these lines passes suc- cessively across all the others till it rests directly on unmoved rocks. The period of terrestrial disturbance was probably a prolonged one, and this inference is strengthened by other evidence to be afterwards adduced. The direction of movement has been on the whole from the E.S.E. Bordering the west coast of Sutherland and Eoss there is a strip of ground about 10 or 15 miles broad and some 90 miles long, in which the rocks have not been displaced. East of that strip, along a belt of dislocation varying up to five or six miles in breadth, the disturbances become increasingly numerous and powerful to- wards the interior, until at last a gigantic thrust-plane is encountered, above and beyond which the rocks have been so crushed and altered, that it is for the most part no longer possible to tell what their original character has been. They a^e now flaggy schists — the younger " quartzose and gneissose flagstones " of Murchison, " the Moine schists " of the Geological Survey. The enormous amount of fracturing, displacing and crushing caused by these terrestrial disturbances has resulted in the develop- ment of regional metamorphism on an extensive scale. Every stage can be traced from a sandstone or conglomerate into a perfect schist, and from the most typical coarse Archaean gneiss into a fine lami- nated slate. Where the feeblest amount of alteration has taken place, the rock has been merely somewhat crushed, its larger crystals or pebbles have been fractured, and the separated portions have been recemented. A further stage is shown where the fine material of the rock has been more comminuted and has been drawn out round the flattened and elongated crystals or pebbles. The latter give way in proportion to their power of resistance. The felspars and hornblendes are first left as "eyes" and then crushed down till they disappear in the general matrix. The harder quartz-pebbles of the conglomerates have resisted longer; but they too, in the planes of great movement, are found to be pulled out to twice or four times their length, or to be flattened out into mere thin plates like pennies. One of the most singular proofs of this internal movement of the component particles of even so obdurate a rock as quartzite is shown by the deformation of the worm-tubes. As these tubes come within the influence of the movement their vertical position changes into an inclined one, and they Vol. XII. (No. 83.) 2 o 540 ^^' Archibald Geikie [June 7, becoroe gradually flatter and more drawn out till at last, before they cease to be traceable, they appear as mere long ribbons on the surface of the rock, which then becomes a quartz -schist. Along the planes of intense crushing the original structure of a rock is entirely eifaced, its crystals or grains are ground into fragments, and it acquires a streaked laminated structure like a shale or slate. But for the most part, concomitant with the mechanical destruc- tion of the various rocks, there has been a chemical and mineralogical re-arranf»ement of their particles. Out of their broken-down materials new minerals have crystallised, and this process of recon- struction has, in the most thoroughly altered masses, proceeded so far that the whole new structure is now crystalline. In this manner, mica, quartz, felspar, hornblende, and other minerals, have been developed, and have arranged themselves along the lines of movement in the crushed rock. These lines, approximating to the surfaces of the threat tlirust-iilanes, may be utterly discordant from the structure- lines, such as those of foliation or bedding, in the original mass. Eocks of this character are true schists, and I know of no internal or ■ external signs by which, apart from field-evidence, they are to be distinf^uished from Archaean schists as to the derivation of which we can only guess, and which, therefore, must in the meantime be con- sidered as original rocks. By the aid of the microscope, much assistance is obtained in tracin^y out the mineral transformations which have taken place in the course of this regional metamorphism. To show the larger features of the change, so far as they can be judged of in hand-specimens, I exhibit on the table a series of pieces of the crushed gneiss, quartzite, and conglomerate ; and to illustrate the internal changes I show a selection of slides on the screen, photographed from thin slices of the rocks as seen under the microscope. The importance of the discovery of this belt of extreme compli- cation in the north-west Highlands can hardly be overestimated. It gives us the key to the geological structure, not only of the Highlands, but of all the areas of younger crystalline schists in our own area, and will doubtless be found to explain much in the geological struc- ture of Scandinavia. The lines of maximum thrust-planes can be followed for 100 miles, from the north of Sutherland into Skye; but this is only a small part of their extent. They can be picked up again in the west of Mayo and Donegal, a total distance of some 400 miles. That similar lines of movement have aifected Scandi- navia and produced the distinctive strike of the rocks there can hardly be doubted, so that the total length of disturbed country in north-western Europe probably exceeds 1600 miles, trending in a general north-north-east direction. How far the influence of the great terrestrial movements extended eastwards from what now appears as the belt of maximum dis- turbance, and what effect it had upon the configuration of the surface, are questions to which as yet no satisfactory answer can be given. 1889.] on the Highlands of Scotland and the West of Ireland. 541 It is difficult to suppose that such colossal displacements and frac- tures of the crust should not have powerfully affected the superficial topography of the time. They may have produced a high mountain range, or a succession of parallel ranges, extending along the north- west of Europe. The existence of some such mass of land is needed to account for the vast piles of sediment of which the Paleeozoic, Secondary, and Tertiary formations have been built up. So great, however, is the antiquity of these terrestrial movements, so continual and gigantic has been the denudation, and so repeated have been the oscillations of level, that the upheaved land has been reduced to the fragments that now form the Highlands and Islands of the west of Ireland, of Scotland, and of Scandinavia. It is quite clear that during the disturbances in the north-west region the main thrust came from the eastward. It will be interesting to discover how far towards the east these disturbances affected the structure of the rocks beneath. That it reached across the whole breadth of the Scottish Highlands, that is for a distance of 100 to 130 miles, can be conclusively proved. That it extended much further and embraced within its area the whole of the Silurian regions of the three kingdoms can, I think, be shown to be highly probable. To understand this part of the problem it is necessary to consider the structure of the ground immediately to the east of the belt of extreme complication in the north-west Highlands. I have said that the displacements and metamorphism "increased in intensity from west to east, until at last, by a final gigantic thrust, a series of re- constructed schists has been driven over rocks whose origin can still be determined. Among these eastern schists it is occasionally possible to detect more or less reliable traces of the original rocks out of the crushing down of which they have been formed. Thus we find in the northern part of the area slices of Archaean and eruptive rocks, and in the south an increasing amount of material which has been derived from the destruction of the red Cambrian sandstones. It is tolerably evident that in the broad band of country which extends from the belt of complication eastwards to the Moray Firth and the line of the Great Glen, and embraces the mountainous tracts of Sutherland, Ross, western Inverness-shire, and north-western Argyll- shire, the lower parts of the Geological Eecord are repeated again and again. It is mainly the Archaean platform, with its covering of Cambrian sandstones, and possibly the lower parts of the Silurian series, which have been broken up, plicated, crushed, and converted into the series of crystalline schists that form the picturesque heights of Ben Hope and Ben Klibric southward to Moidart and Morven. Nevertheless when this wild tract of country comes to be mapped out in detail, there will probably be found intercalated bands of higher formations which have here and there been caught in folds of tho lower rocks. But when we pass eastwards from the Great Glen into the moun- tains of eastern Inverness-shire, Perthshire, and the south-western 2 0 2 542 Mr. Archibald Geihe [June 7, Highlands, we encounter a totally different series of rocks. Though greatly j^licated, dislocated, crushed, and metamorphosed, these rocks can be recognised as unquestionably, in the main, of sedimentary origin. They must be many thousands of feet in thickness, including among their members such rocks as conglomerate, pebbly grit, quartzite, black slate, audalusite slate, phyllite, mica-schist, fine flagjzy gneiss, and limestone, together with intrusive sheets and bosses of various eruptive rocks. Some of the groups of this series can be followed and mapped for long distances with nearly as much ease as the members of a succession of unaltered Pala30zoic or Secondary formations. There is a belt of limestone, for example, which has been traced by the Geological Survey almost continuously from the coast of Banffshire to the west of Argyllshire, through the very heart of the Highlands — a total distance of not much less than 200 miles. These limestones have for the most part become so thoroughly crys- talline that fossils can hardly be expected to be found in them, though there are occasional less altered portions of rock which may eventually prove to be fossiliferous. The limestones are associated with quartzites and schists, as unaltered limestones are with sand- stones and shales. I cannot myself doubt that they have been formed by the aggregation of the remains of calcareous organisms. The same rocks are prolonged into the north of Ireland, where one of the dark limestones at Culdaff" has lately yielded certain bodies which some palaeontologists have declared to be the remains of a coral (Favosites). The black slates which so closely resemble the dark carbonaceous shales of the Lower Silurian region of south Scotland liave afforded in Donegal some curious pyritous markings strongly suggestive of graptolites. Out of this enormous mass of metamorphosed sedimentary strata the Scottish Highlands east of the Great Glen are built up, as well as the region which extends southwards across the north-west of Ireland as far as the centre of County Galway. The first question that requires an answer with regard to it has reference to its relation to the fossiliferous quartzites and limestones of the north-west. Murchison, who led the way in the investigation of the stratigraphy of the Highlands, believed that the quartzites and limestones of the Central Highlands lay towards the base of the whole series of post- Cambrian rocks, and were the south-eastward extensions of those of Sutherland. But recent investigations throw some doubt on this view, which at the time it was promulgated seemed so natural and simple. We know that the quartzites and limestones of the Central Hi. de. MB J. [Jhe £tfi/or)-^ oumal of the Eoyal Micr:- - Part 3. Sto. Eo^Indiz — Vol. XXI. Xo. 2- Svo. 1SS9. E'iiion — ^Asierksui Jorumai oi Science for June. 1SS9. Svo. Asalvst for Jxme, 1S.S9. Sv.->. Athensum f : - "^ ^ -. Ito. Chemical Xe . 1S^^. 4t/ Chemist and 1 r June, 1SS9. Svo. El«?m.:&l Er- 'me. 1S8&. foL Eiurinc^r I'.-r foL Ei:^etrli:g i- :r Juiir. iivS9. foL Hor:l sical J. -amal for June, ISS^. Svo. Indusiries f :r June, 185«. fol- Ircn f>:T June. lSSc». 4to- Ir : , T_. me. 1SS9. Sto. 31 X. -ito. PL for June. 1SS9. Sto. B. - .Tnne. IS^^. 4to. T : Tone. 1SS9. Sv... Z: 4to. ^' : . - -• T - -^1, Xo. S4}. Svo. 1SS9. 1SS9. ' "; J .. ' _ — _c, Xew Series, ToL XL Xo. 6. 'lf>i». ---.-• G"—:r''- ^"'^ J— - ^ - --Atti,ToLXn. Disp. 1. Svo. 1SS9. ^ - — ' ITU. ! Svo. 1S89- — Prw^inss. 1889. X fx L Svo. 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The Special Thanks of the Members were retnmed to the EeT. JoKS- MACNArGHT, M.B.I, for his second donation of £50 for improve- ments in the BniLiing. The Pbesents received since the last Meeting were laid on the table, and the thanks of the Members retnmed for the same. viz. : — FBOM The GorernoT-General of India — GtBological Snrvev of India : Becords. YcL X^TT Parts. 4to. 1SS9. The French Government — Doouments Inedits sur I'Histoire de France: Lettres du Cardinal Mazarin. Par A. Cheruel. Tome V. 1653. 4to. 1SS9. Academy of Xatural Sciences, Philadelphia — ^Proceeding's, 1SS9, Part 1. Sto. Accademia dei Lincei. Beale. Eoma — ^Atti, Serie Qnarta : KendieontL lo Semes- tre, YoL Y. Faso. 7-12. Svo. 1SS9. American Association for the Advancement of Science — Proceedings, oTth Meetin? held at Cleveland, ISSS. Svo. 1SS9. ' American PhiloAjpliicai S:\uety — Proceedimrs, YoL XXYL Xo. 129. Sva 1SS9- Antiquaries, Society of — Proceedings, Yol. XII. No. 3. Svo. 1SS9. Asiatic Society, Boyat (^China Branch) — Journal, Yol. XXIII. Parts 2. 3. Xcw Series, Svo. 1SS9. 566 General Monthly Meeting. [Nov. 4, Astronomical Society, iJoj/aZ— Monthly Notices, Vol. XLIX. No. 8. 8vo. 1889. Australian Museum, Sydney — Keport for 1888. 4to. 1889. Banhers, Institute o/— Journal, VdI. X. Parts 7, 8. 8vo. 1889. Bavarian Academy of Sciences — Abhandlun2;en, Band XVI. Abth. 3. 4to. 1889. Sitzungsberichte, 1888, Heft 3; 1889, Heft 1. 8vo. 1889. Belgique, Academic des Sciences, &c. — Memoires, Tome XLVII. 4to. 1888. Memoires couronnes et des savans etrangers, Tome XLIX. 4to. 1889. Me'moires couronnes et autres memoires, Tomes XL.-XLII. 8vo. 1889. Bulletins de I'Academie, Tomes XIV.-XVII. Svo. 1889. Annuairesde 1888 et 1889. 8vo. 1889. Birmingham Philosoiihical Society — Proceedings, Vol. VI. Part 1. 8vo. 1889. British Architects, Royal Institute o/— Proceedings, 1888-9, Nos. 17-20. 4to. Calendar, 1889-1'0. Svo. 1889. British Museum (Natural History) — Catalogue of Fossil Eeptilia and Amphibia, Part 2. Svo. 1889. Catalogue of Hindustani Printed Books. By J. F. Blumhardt. 4to. 1889. California, University of — Register, 18S8-9. Svo. Canadian Jn.?f<7u?fi— Proceedings, 3rd Series, Vol. VI. Fas. 1. Svo. 1889. Chemical Industry, Society o/— Journal, Vol. VIII. Nos. 7-9. Svo. 1889. Chemical Society — Journal for July-October, 1889. Svo. Chief Signal Ojicer, U.S. Army— Aunusl Report for 1888. Svo. 1889. Civil Engineers' Institution — Proceedings, Vol. XCVII. Svo. 1SS8-9. Colonial Institute, /I'o^a?— Proceedings, Vol. XX. Svo. 1889. Clinical Society — Transactions, Vol. XXII. 8vo. 1889. Cracovie, V Academic des Sciences — Bulletin, 1889, No. 6. Svo. Crisp, Frank, Esq. LL.B. F.L.S. d-c. M.E.I. {the Editor)— J omnal of the Royal Microscopical Society, 1889, Part 4. Svo, Devonshire Association for Advancement of Science, Literature, and Ai't — Report and Transactions, Vol. XXI. Svo. 1889. Devonshire Domesday, Part VI. Svo. 1889. Dyer, F. W. Esq. {the Author)— The Lingualumina : a Language for International Communication, Part 1. Svo. 188'.>. East India Association— J omna\, Vol. XXI. Nos. 3, 4, 5. Svo. 1889. Editors — American Journal of Science for July-October, 1889. Svo. Analyst for July-October, 1889. Svo. Athenseum for July-October, 1889. 4to. Chemical News for July-October, 1889. 4to. Chemist and Druggist for July-October, 1889. Svo. Electrical Engineer for July-October, 1889. fol. Engineer for July-October,' 1889. fol. Engineering for July-October, 1889. fol. Horological Journal for July-October, 1889. Svo. Industries for July-October, 1889. fol. Iron for July-October, 1889. 4to. Ironmongery for July-October, 1889. Murray's" Magazine for Julv-October, 1889. Svo. Nature for July-October, 1889. 4to. Photographic News for July-October, 1889. Svo. Revue Scientifique for July-October, 1889. 4to. Telegraphic Journal for July-October, 1889. Svo. Zoophilist for July-October, 1889. 4to. Electrical Engineers, Institution o/— Journal, No. 81. Svo. 1889. Florence Bihlioteca Nazionale Cew^raZe— Bolletino No. 91. Svo. 1889. Indice Cataloghi, 1 Codici Palantina VII. Vol. I. Fas. 2; IV. Vol. I. Fas. 9-10. Svo. 1889. FranMin Institute— Journal, Nos. 763-766. Svo. 1889. Geographical Society, Royal — Proceedings, New Series, Vol. XI. Nos. 7-11. Svo. 1889. Supplementary Papers, Vol. II. Part 4. Svo. 1889. 1889.] General Monthhj Meeting. 567 Geological Institute, Imperial, Vv-nna — Verhandlungen, 1889, Nos. 7-9. 8vo. Jahrbuch, Baud XXXIX. Heft 1, 2. 8vo. 1889. Geological Society— QusiVterly Journal, No. 179. 8vo. 1889 Georgofili Reale Accademia — Atti, Qnaita Serie, Vol. XII. Disp. 2, 3. 8vo. 1889. Goppelsroeder, Dr. F. (the Author)— Vhev Capillar- Analyse. 8vo. 1889. Farbelectro-Clieraische Mittheilungen. 8vo. 1889. Harlem, Societe Hollandaise des Sciences — Archives Ne'erlandaises, Tome XXIII. Liv. 3, 4. 8vo. 1889. (Euvres completes de C. Huygens. Tome II. 1657-9. 4to. 1889. Dagh-Register, 1659. 8vo. 1889. Tijdschrift voor Inaische Taal-, Land- en Volkenkunde, Deel XXXII. Af. 6. 8vo. 1889. Notulen van de Algemeene en Bestuurs-Vergaderingen, Deel XXVI. Af 4 8vo. 1889. Eofmann, Herr A. W. von (the Author) — Zur Erinnerung an Vorano-egangene Freun.le. 8 vols. 8vo. 1888. Iron and Steel Institute — Journal for 1889, Vol. I. 8vo. 1889. John Hopkins University — American Chemical Journal, Vol. XI. Nos. 1-6. 8vo. 1889. American Journal of Philo'ogy, Vol. IX. No. 4, and Vol. X. No. 1. 8vo. 1889. University Circulars, Nos. 69-75. 4to. 1889. Studies in Historical and Political Science, 7th Series, Nos. 2-9. 8vo. 1889. Karisas Academy of Sciences — Transactions. Vol. X. 1S85-6. 8vo. 1887. Linnean Society — Journal, Nos. 122, 133-135, 171. 8vo. 1889. Index to Journal, 1838-86. 8vo. 1888. Transactions : Zoology, Vol. II. Part 18 ; Vol. IV. Part 3 ; Vol. V. Parts 1-3. Botany, Vol. II. Part 16. Lisbon Academy of Sciences — Historia do Infante D. Duarte. Por J. Eamos Coelho. Tomol. 8vo. 1889. Madrid Royal Academy of Sciences — Memorias Tomo XIII. Parts 2, 3. 4to. 1889. Revista, Tomo XXII. Nos. 5-7. 8vo. 1889. Manchester Geological Socidy — Transactions, Vol. XX. Parts 9-10. 8vo. 1889. Manchester Literary and Philosophical Society — Memoirs and Proceedings, Vol. II N.S. 8vo. 1889. Manchester Steam Users' Assodation — Boiler Explosions Act, 1882. Report, Nos. 224-283A. 4to. 1889. Manila Universidad de Sto. Tomas— Discurso, Por el R. P. Fr. Jaime Andrew. 4to. 1880. Mechanical Engineers' Institution — Proceedings, 1889, No. 2. 8vo. Menshrugghe, M. G. Van der (the Author) — La Couche Superficielle libre d'uii Liquide. 8vo. 1889. Un Genre Particulier d'Experiences Capillaires. 8vo. 1889. Meteorological Office— Rom\j Readings, 1886, Part 4. 4to. 1889. Meteorological Observations at Stations of Second Order for 1885. 4to, 1889. Weekly Weather Reports, Nos. 26-43. 4to. 1889. Meteorological Society, Boyal — Quarterly Journal, No. 71. 8vo. 1889. Meteorological Record, No. 33. 8vo. 1889. Ministry of Public Works, i?ome— Giornale del Genio Civile, Seria Quinta, Vol. III. Nos. 5, 6, 7. And Disegni. tbl. 1889. Musical Association— VroceedmgB, 15th Session, 1888-89. 8vo. 1889. New York Academy of Sciences — Transactions, Vol. VIII. Parts 1-4. 8vo. 1889. Annals, Vol. IV. Parts 10-11. 8vo. 1889. North of Enqland Institute of Mining and Mechanical Engineers — Transactions, Vol. XXXVIII. Part 3. 8vo. '1889. Numismatic Society— (J^hmmcle and Journal, 1889, Parts 1-2. 8vo. 1889. Odontological Society of Great Britain — Transactions, Vt)l. XXI. No. 8. New Series. 8vo. 18S8. Pennsylvania Geological Survey — Atlases to Report, 1889. 8vo. Museum Catalogue, Part IIL 8vo. 1889. 5G8 General Montldy Meeting. [Nov. 4, Pharmaceutical Society of Great Britain — Journal, July-October, 1SS9. 8vo. Photofjrajjhic Society— JouTnal, Vol. XIII. No. !♦; Vol." XIV. No. 1. 8vo. 1889. Freusi^i^cUe Ahademie cler Wissenschafteu — Sitzungsberichte, Nos. I.-XXXVIII. 8vo. 1889. Richardson, B. W. M.D. F.E.S. M.B.I. {the Author)— The Asclepiad, Vol. VI. No. 23. 8vo. 1889. Bio de Janeiro Observatory —'RevUta, Nos. 6-8. Svo. 1889. Boyal College of Surgeons in England — Calendar, 1889. Svo. 1889. Boyal DuUin Society — TraTisactious, Vol. IV. Parts 2-5. -Ito. 1889. Proceedings, Vol. VI. Parts 3-6. 8vo. 1889. Boyal Historical and Archxological Association of Ireland — Journal, Vol. IX, (4th iSeries), No. 79. Svo. 1889. Boyal Irish ^Icadt-m?/— Transactions, Vol. XXIX. Parts 6-11. 4to. 1889. Boyal Society of Canada — Proceedings and '1 nmsactions, Vol. VI. 4to. 1888-9. Boyal Society o/ioncZo/«— Proceedings, Nos. 280-283. Svo. 1889. Jioyal Society of New South Wales — Journal aud Proceedings, Vol. XXII. Part 2. Svo. 1889. Saxhy and Farmer, Messrs. {the Publishers) — Railway Safety Appliances, fol. 1889. Saxon Society of Sciences, Boyal — Mathematisch-physifcclie Classe: AbhanilluuLf. Band XV. No. 6. Svo. 1889. Berichte. 1889, No. 1. Svo. 1889. Smithsonian Institute — Annual Report, 1886, Part 1. Svo. 1889. Societe Archeologique du Midi de la France — Bulletin, Nouvelle Series, No, 3. Svo. 18h9. Society of ^r^s— Journal for July-October, 1889. Svo. Statistical Society— Jommx], Vol. LII. Parts 2-3. Svo. 1889. Stevens, W. Le Cunte, Esq. (the Author) — The Diflraction of Sound. (Jour. Franklin Inst.) Svo. 1SS9. St. Pe'tersbourg AcacUmie Impe'riales des Sciences — Me'moires, Tome XXXVI. Nos. 14-16. 4to. 1889. Surgeon-General, U.S. Army — Index Catalogue of Library, Vol. X. 4to. 1889. Ttyler Museum — Archives, Serie II. Vol. III. Partie 3. 4to. 1889. United Ser> ice Institution, Boyal — Journal, Nos. 149-1.50. Svo. 1889. United States Navy — General Information Series, No. 8. Svo. ISSU. Uruguay Consulate — General Description and Statistical Lata of Uruguay. 4to. 1889. Vereins zur Beforderung des Gewerbfleises in Preussen — Verliandlungen, 1889 : Helt 6, 7. 4to. Victoria Institute— TiiiB&act'ious, Nos. 89-90. Svo. 1889. Vincent, Benjamin. Esq. Hon. Librarian R.I. (the Editor) — Hadyn's Dictionary of Dates. 19th Edition. Svo. 1889. Wright & Co. Messrs. John (the Publishers)— llcixnh Troubles of City Life. By G. Herschell. Svo. 1889. Zoological Society — Proceedings, 1889, Parts 2, 3. Svo. Transactions, Vol. Xtl. Part 9. 4to. 1889. 1889.] General Monthlij Meeting. 569 GENERAL MONTHLY MEETING, Monday, December 2, 1889. Sir James Ceichtox Browxe, M.D. LL.D. F.R.S. Treasurer and Yice-President, in the Chair. Charles Vernon Boys, Esq. F.E.S. A.R.S.M. Frederick Bayard Wiggins, Esq. Alfred Fernandez Yarrow, Esq. M. Inst. C.E. were elected Members of the Eoyal Institution. The Managers reported that they had re-appointed Professor James Dewar, M.A. F.R.S. as Fullerian Professor of Chemistry. The following Lecture Arrangements were announced : — Professor A. W. Kicker, :\r.A. F.E.S. M.B.I. Professor of Physics in the Normal School of Science and Eoyal School of Mines, South Kensington. Six Lectures (adapted to a Juvenile Auditorv) on Electricity. On Dec. 28 (Saturday), Dec. 31, 1889 ; Jan. 2, 4, 7, 9, 1890. George John Kosianes, Esq. M.A. LL.D. F.E.S. M.E.I. Fullerian Professor of Physiology, E.I. Ten Lectures, constituting the third part of a Course on Before and After Darwin (The Post-Darwinian Period). On Tuesdays, Jan. 21 to March 25. Edwin Eoscoe Mclltns, Esq. Three Lectures on Scflpture in relation TO the Age. On Thursdays, Jan. 23, 30, Feb. 6. The Eev. Canon Ainger, M.A. LL.D. Three Lectures on The Three Stages of Shakspeare's Art. On Thurt>daijs, Feb. 13, 20, 27. Frederick Niecks, Esq. Author of the ' Life of Chopin.' Four Lectures on The Early Developments of the Forms of iNSTRruENT^L Music (with Musical Illustrations). On Tliursdays, March 6, 13, 20, 27. Professor Flower, C.B. D.C.L. LL.D. F.E.S. Three Lectures on The Natural History of the Horse and of its Extinct and Existing Allies. On Saturdays, Jan. 25, Feb. 1, 8. 'J^HE Eight Hon. Lord Eayleigh, M.A. D.C.L. LL.D. F.E.S. M.R.I. Pro- fessor of Natural PhilosoiDhy, E.I. Seven Lectures on Electricity and Magnetism. On Saturdays, Feb. 15, 22, March 1, 8, 15, 22, 29. The Presents received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. : — FR03I Aceademia del Lincei, Reale, Boma — Atti Serie Quarta : Eendiconti. 2*^ Semes tre. Vol. V. Fasc. 3, 4. 8vo. 1889. Antiquaries, Society of — Archseologia, 2nd Series, Vol. I. 4to. 1889. Aridoieliaii ^Soc/ef?/— Proceedings, Vol. I. No. 1. 8vo. 1889. Asiatic Society, Boyal (Bomljay Branch) — Journal, Vol. XVH. No. 47. 8vo. 1889. Astronomical Society, Boyal — Monthly Notices, Vol. XLIX. No. 9. Svo. 1889. Australian Museum, Sydney — Supplement to Eeport for 1888. 4to. 1889. Bankers, Institute o/— Journal, Vol. X. Part 9. 8vo. 1889. British Arcliitects. Boycd Institute of — Proceedinsrs, 1889-90, Nos. 1-3. 4to. Transactions, Vol. V. N.S. 4to. " 1889. British Association for the Advancement of Science — Eeport of Meeting held at Batli, 1888. 8vo. 1889. - 570 General Monthly Meeting. [Dec. 2, 1889. British Museum (Natural History) — Lepidoptera Heterocera, Part VII. 4to. 1889. Cambridge Philosophical Society — Transactions, Vol. XIV. Part 4. 4to. 1889. Proceedings, Vol. VI. Part 6. Svo. 1889. Canada, Geological and Natural History Survey of — Canadian Palaeontology, Vol. I. Part 2. Svo. 1889. Chemical Industry, Society o/— Journal, Vol. VIII. No. 10. Svo. 1889. Chemical Societi/ — Journal for November, 1889. Svo. Crisp, FranK; Esq. LL.B. F.L.S. &c. M.R.I, (the jE:(Zt7or)— Journal of the Royal Microscopical Society, 1889, Part 5. Svo. Editors — Americau Journal of Science for November, 1889. Svo. Analyst for November, 1889. Svo. Athenaeum for Novemlaer, 1889. 4to. Chemical News for November, 1889. 4to. Chemist and Druggist for November, 1889. Svo. Electrical Engineer for November, 1889. fol. Engineer for November, 1889. fol. Engineering for November, 1889. fol. Horological Journal for November, 1889. Svo. Industries for November, 1889. fol. Iron for November, 1889. 4to. Ironmongery for November, 1889. Murray's Magazine for November, 1SS9. Svo. Nature for November, 1889. 4to. Photographic News for November, 1889. Svo. Revue Scientilique for November, 1889. 4to. Telegrapbic Journal for November, 1889. Svo. Zoophilist for November, 1889. 4to. Franklin Institute— Journal, No. 7G7. Svo. 1889. Geological Societij—Qua.\tei\y Journal, 'No. ISO. Svo. 1889. Harlem, Soci^t^ HoUandaise des Sciences — Archives Neerlandaises, Tome XXIII. Liv. 5. Svo. 1889. Junior Engineering Society — Addresses, &c. Svo. 1SS5-8, Madras Government Central Museum — Report, 1S8S-9. fol. 1SS9. Marvin, Charles, Esq, — Our Unappreciated Petroleum Empire. Svo. 1889. Maryland Medical and Chirurgical Faculty — Transactions, 91st Session, April, 1889. Svo. 1889. Meteorological Office— ^Yeek\J Weather Reports, Nos. 44-47. 4 to. 1889, Ministry of Public Works, Borne — Giornale del Genio Civile, Seria Quinta, Vol. III. Nos, 8, 9. And Disegni. fol. 1889. Numismatic Society — Chronicle and Journal, 1889, Part 3. Svo. 1889. Odontological Society of Great Britain — Transactions, "\'ol. XXII. No. 1. New Series. Svo. 1889. Pharmaceutical Society of Great Britain — Journal, November, 1889. Svo. Photographic Society — Journal, Vol. XIV. No. 2. Svo. 1889. Physical Society of London — Proceedings, Vol. X. Part 2. Svo. 1889. Richardson, B. W. M.D. F.R.S. M.R.I, (the Author)— The Asclepiad, Vol. VI. No. 24. Svo. 1889. Rio de Janeiro Observatory — Revista, No. 9. Svo, 1889. Royal Institution of Cornicall — Journal, Vol. IX. Part 4. Svo, 1889. Royal Society of Tasmania — Papers and Proceedings for 1888. Svo. 1889. Seismological Society of Japan — Transactions, Vol. XIII. Part 1. Svo. 1889. Society of Architects — Proceedings, Vol. II. Nos. 1^ 2. Svo 1889. Society of ^rfs— Journal for November, 1889. Svo. St. Petersbourg Academic Impe^riales des Sciences— Memoires, Tome XXXVI. No. 17; Tome XXXVII, No. 1, 4to. 1889. Vereins zur Beforderung des Geiverbfleises in Preussen — Verhandlungen, 1889 : Heft 8. 4to. Weylier, C. L. Esq.- (the Author) — Sur les Tourbillons Trombes, Tempetes et Spheres Tournantes. 2nd edition. Svo. 1889, Mr. A. Gordon Salamon on Yeast. 571 WEEKLY EVENING MEETING, Friday, March 29, 1889. William Ckookes, Esq. F.E.S. Vice-President, in the Chair. A. Gordon Salamon, Esq. A.R.S.M. F.I.C. F.C.S. M.B.I. Yeast. " Foe the first time in the history of the science, we are justified in entertaining the sanguine, nay the certain hope, that medicine, so far as epidemic illnesses are concerned, will soon be rescued from em- piricism and placed upon a sound scientific basis. When this great day shall arrive, mankind will, in my opinion, acknowledge that to you is due the greatest sliare of its gratitude."* These words were penned in this building by Professor Tyndall just thirteen years ago, and were addressed to M. Pasteur. The reflection that they had reference mainly to researches which the great French investigator had carried out during several years in connection with the subject of this evening's discourse, will suffice to constitute for it a sufficient claim upon your attentive consideration. It will be within the knowledge of those who have closely fol- lowed the work of Pasteur, and have noted how contracted is the circle of actual experiment, how expanded — yet how accurately traced — the sphere of legitimate induction, that the results arising out of his examination into the nature and properties of yeast constituted the weapons which demolished the mischievous doctrine of spon- taneous generation, fashioned the modern views respecting putrefac- tive decomposition, and prepared the way for the prosecution of those investigations which have already revolutionised the theory and practice of Hygiene, Therapeutics, and Surgery. All this was not effected without concomitant controversy of the keenest kind. Indeed, the protracted dispute which Pasteur sus- tained with Liebig, and also with Fremy, regarding the rationale of the decomposition of sugar solutions by yeast must always rank among the most brilliant of his efi*orts. But, perhaps, the most interesting feature in connection with his experiments upon yeast is that his abstruse physiological researches should have been capable of direct translation into terms of industrial utility ; and but for other work which he himself has done in this direction, and but for that of Hansen, which I propose to consider this evening, it would jDrobably be unique in the history of technology. As regards the value of that work, when considered from a com- * M. L. Pasteur, 'Etudes sur la Biere,' p. 382. Paris, Gauthier-Villars, 1876. Vol. XII. (No. 83.) 2 q 572 Mr. A. Gordon Salamcm [March 29, mercial standpoint, it may. so far as tliis conntry alone is concerned, most nndonbtedly be estimated by millions sterling : and when all those problems which have arisen ont of the investigation — and which have of necessity been taken in hand by others — shall have been solved, it will be found that the saving due to it will have reached a total which, in terms of potmds, shillings, and pence, would appear truly colossal. For this to be possible, yeast must have a very important role to perform in connection with certain of our industries, and indeed is used in quantity which is really somewhat astonishing when the figures are cast up for the first time. I have endeavoured, with the assistance of my friends, Mr. Ban- nister. Deputy Priucipal of the Laboratory of Somerset House, and Mr. Frank Wilson, the head brewer to Messrs. Combe and Co., to calculate the amount of yeast (reckoned as pressed dry yeast ) which is annually produced and used in the United Kingdom. The results are given in the following table, the figures of which, though in some cases necessarily estimated, may, I think, be regarded as very nearly accurate. Yeast AxxrALLv Used axd Peoduced in the United Kingdom. (Calcnlated as Pressed Yeast.) In Erc-ir,-:— Tons. Used for '^ Pitching " 4,250 Produced in addition to above * 25.500 Ton*. 29.750 In DisUU'i\:-~ Used for "Pitching" 3,100 /n Vimgar-makinj — Used in " PitcLdng " and produced 125 In Bakiri'j — Used for making " Sponge " t 14,000 Total 46.975 * Mainly employed for use in foreign distilleries, and having value to brewers of about £127, 50<^ t Average imports of foreign yeast especially grown and prepared fur use in baking, 12,594 tons, having declared average value to imp^^rter of £684,156 Approximate amount annually paid by merchants for yeast used in the United ELingdom £911. 500 Now this great quantity of yeast — and when we regard yeast, as we shall do here, as a cultivated fungus, it is a great quantity — is used in virtue of the property it possesses of decomposing certain of the carbohydrates into alcohol and carbonic acid. In the production of beer and spirit it is employed with the object of producing alcohol : in vinegar-making with the same object, the alcohol being subsequently oxidised by means of another organism into acetic acid. In each of these cases the carbonic acid gas is a valueless bye-product ; but in bread-making the conditions are reverse i, the yeast being primarily employed with a view to the dis- 1889.] on Yeast 573 engagement of carbonic acid gas. It is throngh its agency that the production of a light and vesicular bread is ensured. The yeast being brought into intimate contact with carbohydrates suitable for decomposition, effects the generation of carbonic acid gas, which, as it is disengaged, makes an effort to force its way through the dough. This is resisted by the yery plastic gluten of the flonr. The result is to effect what is termed the raising of the '•' sponge." It will be unnecessary to remind yon that this decomposition of carbohydrates into alcohol and carbonic acid gas by means of yeast constitutes one phase of the phenomenon of alcoholic fermentation. It is somewhat difficult to ascertain when it was first conjectured that this was due to the growth of yeast ; but it is clear that Caignard de la Tour had formed a strong opinion on the subject more than sixty years ago. for lie wrote, " if yeast could thus ferment sugar, it must surely be by some influence due to its yegetation and its life." Indeed, there are many passages in bis works, as well as in those of that great observer, Schwann, which indicate that about that period a very firm grip had been obtained of the theory of fermentation as now accepted ; but it had to be relinquished, as it clashed with the more speculative views of Liebig and his supporters. So widespread was the influence of this great school, that operations and experimental observations contradictory of its doctrines were so neglected as to be forgotten, or were combated by so strong a combination of intellect as to be prac- tically untenable. It was reserved for Pasteur to rediscover the growth of yeast previonsly noted by Caignard de la Tour and Schwann ; to add to their observations by an abundance of fresh investigations : and to formulate a theory of alcoholic fermentation, which, has at least the merit, in contradistinction to others, of being a logical interpretation of accurate experiment ; one, moreover, which, in my himible judg- ment, is quite capable of ultimate reconciliation witb some at least of the more important views of the German chemist. Pasteur's experiments placed it beyond doubt tbat tbe decom- position of carbohydrates by means of yeast is neither more nor less than one of tlie manifestations of vitality by yeast, a ftmgoid organ- ism capable of growth and reproduction. Since his results have been published it has been almost proved that this decomposition takes place witbin the organism, and in any case it is proved that Eilcohol and carbonic acid are to be regarded as products excreted dnring phases of its life-history. This being the case, it manifestly becomes necessary to study the biology of the organism, in order to acquire further information respecting the nature of the chemical reactions involved in the decomposition. But before doing this, it is advisable, at any rate for the purposes of this discourse, to restrict the signification of the t^rm ferment : otherwise confusion must inevitably result. Even to-day we are accustomed to speak of two classes of ferments — organised and soluble. The alcoholic ferment, yeast, for example, is a cryptogam of definite 2 Q 2 574 Mr. A. Gordon Salamon [March 29, organised structure, and its power of effecting the degradation of carbohydrates into alcohol and carbonic acid gas is but one of the features connected with its life-history. Moreover, it is one which is typical of a whole group of fungi. The soluble ferments, on the other hand, are unable to effect this radical decomposition, but are endowed with the property of hydro- lising, and thereby producing a constitutional modification or partial degradation of some carbohydrates and other substances of complex composition. They are probably typified by certain molecular group- ings common to them as a class, but they are not organised, and have indeed nothing beyond what I have stated in common with fungi. It is true that certain of these soluble ferments are contained in fungi which themselves are capable of producing alcoholic fermentation, such, for instance, as the invertase in yeast ; but they are not contained in all alcohol-producing fungi. Their function, when present, would seem to be that of a reserve material, capable, when necessary, of effecting the preparation of a saproj^hytic food by alter- ative action, so as to adapt it for subsequent radical attack by the fungus. In this connection it must not be forgotten that suli^huric acid, hydrochloric acid, and indeed most mineral and organic acids, can produce the same alterative action ujDon these carbohydrates, and are employed in very large manufacturing operations for the purpose. It would therefore seem quite reasonable to include these niincral acids among the so-called soluble ferments, if the latter are entitled to rank as a distinct class. Alcoholic fermentation, although caused by the action of yeast, which is a fungus, is by no means peculiar to one j^articular species or geuus of fungi. Indeed, the list of those organisms which, under certain conditions, will excite alcoholic fermentation, is continually being augmented. But the life conditions are now tolerably well understood. The fungal food must be present in a state of solution ; the supply of free oxygen must be extremely restricted ; the tem- perature must be maintained wdthin certain limits for each particular species or variety ; there must be present an adequate but not too great a supply of carbohydrate, preferably a sugar, in solution ; and the fungus must, when immersed in the fluid, be capable of growth and reproduction. With regard to the carbohydrate food, some points of very great interest are noticeable. All carbohydrates are not equally suitable, though in most cases the fungus contains within itself the chemical components that may, when required, adapt it to assimilation. Ordi- nary yeast, for instance, cannot ferment cane sugar ; it has, first of all, to be transformed, by the invertase contained in yeast, or by other known means, into what is known as invert sugar. This con- sists of two glucoses present in equal quantity — the one dextrose, capable, as its name implies, of turning the ray of polarised light to the right; the other, laevulose, capable of rotating it to a definite extent to the left. Both these glucoses have the same composition ; 1889.] on Yeast. 575 but there is probably a difference in their molecular grouping which influences their respective actions towards polarised light. If ordinary yeast — a member of the family of sprouting fungi — be submerged, under proper conditions, in a mixture of equal quantities of these two glucoses, it will be found that it is capable of dis- tinguishing the one from the other, and of exercising a selection with respect to assimilation ; for it will entirely decompose the dextrose before attacking the l^evulose. Indeed, if the fermentation be stopped at the proper jDoint, it is a very good way of obtaining Isevulose. This is by no means the only case in point, as will be seen by reference to the following table : — Selective Action of some Sprouting Fungi for Carbohydrate Food. Saccharomyces cerevisiee .. Can invert cane sugar, and subsequently select dextrose from Isevulose. Can ferment maltose. Cannot decompose malto-dextrin. „ pastorianus ..\ Can invert sugar, ferment maltose, and decom- „ ellipsoideus .. / pose malto-dextrin. „ exiguus.. .. Cannot ferment maltose. Can ferment glucose. „ ajDiculatus .. Cannot ferment maltose. Cannot invert cane sugar. Can ferment dextrin and Isevulose. Torula Can ferment maltose and glucose. Cannot invert cane sugar. Monilia Candida Cannot invert cane sugar, but can ferment it without previous conversion into glucose. In order that yeast, or any fungus capable of exciting alcoholic fermentation, may flourish and reproduce, it is necessary that it shall have an available supply of oxygen. This has to discharge a duty which Pasteur deems analogous to respiration. If it is deprived of oxygen, and is not introduced into a fermentable medium, the yeast will not reproduce, but in a short time will become weak and shrivelled ; but if, before it is too late, a supply of oxygen be introduced, the exhausted organism will revive and again be capable of manifesting all its vitality. If the alcoholic ferment be deprived of a sufficiency of oxygen, and in such circumstances be kept immersed in a medium containing suit- able carbohydrate in solution, it will decompose the latter, in order, among other things, to obtain the necessary oxygen. This decom- position will result in the production of alcohol and carbonic acid gas in strictly definite proportions. 2C,H,,06 = 4aH,0 + 400^. (Glucose) (Alcohol) (Carbonic anhydride) On looking at this equation, one fails to see the available oxygen, although it may be that the decomposition itself suffices for the requirements of what has been termed " the respiration " of the yeast. But what is more likely is, that it is furnished by other decompositions by which the reaction is always attended. Thus Pasteur has proved that in addition to alcohol and carbonic anhydride, 576 Mr. A. Gordon SaJai [March 29, small qiiautities of succinic acid and glycerin always accompany their formation, aud in attempting to state thi?; in the form of an equation, Monoyer satisfactorily accounts for the liberation of oxygen. Thus — 4(C,Hi,0,) + 3H.,0 = C,H,0, + eC.H.O. + 2C0, + 0. (Glucose) (Succinic Acid) (Glycerin) Various opinions have been expressed as to whether tlie presence or absence of oxygen does actually influence the decomposition of sugar and the formation of yeast to the extent indicated by Pasteur. Adolf Mayer, whose opinion upon questions connected with fermentation is justly regarded with great respect, made a series of experiments from which he inferred that the influence was by no means as great as was supposed ; but Schiitzenberger pointed out what certainly looks like a flaw in his method of working, and would induce hesitancy in accept- ing his conclusions. The great difficulty is to ensure the complete permeation of the fermenting fluid by oxygen, which has a tendency, if not corrected, to exercise its influence only upon layers or strata in the fluid. It is found that the rate of fermentation greatly influences the depth to which oxygen will permeate and diffuse, aud that a slow fermentation favours efficient admixture. These conditions have been brought under control by Hoppe-Seyler in a most ingenious and satisfactory mauner.* His experiments upon the poiut in question may be thus stated and tabulated : — Experiment. Units of Sugar decomposed. Units of Alcohol formed. Remarks 1. C0.> absorbed and re- placed by O uniformly diffuseci. 2. Air above fermenting I'O fluid replaced by CO 2, which was also passed in during fermenta- tion instead of O. | 3. Normal fermentation 2-74 Few budding cells ; cell con- tents very granular; alco- holic distillate strotvjly acid. 2*05 { Cell contents normal; alco- holic distillate /t'e6/^ acid. 4 '70 ] Cell contents normal; alco- holic distillate faintly acid. Now, from what has been said it will be understood, indeed it follows, that the amoimt of carbonic anhydride evolved is a measure of the extent to which the decomposition of the carbohydrate has been carried by the alcoholic ferment. But, in order that this state- ment may hold good, it is necessary that whenever the carbonic anhydride is measured, there shall always be present in the fer- menting fluid an excess of the solution of carbohydrate ; for Pasteur * Festschrift von Felix Hoppe-Seyler. Karl J. Trubuer, Strasburg, 1881. 1889.] on Yeast. 577 has proved that, in its absence, the yeast will, when denied free access of atmospheric oxygen, and when fermentation has once started, decompose a portion of itself in order to obtain the necessary elements to maintain its vitality. But given the necessary excess of carbo- hydrate, and assuming that in two or more flasks undergoing alcoholic fermentation the conditions of culture are the same with respect to temperature, pressure, food, and amount of ferment added, it follows that the rate of evolution of carbonic anhydride becomes a measure of the fermentative activity of the fungus respectively producing it. I have here an apparatus devised to effect this measurement. It will be seen to be extremely simple in its working, but I find that it gives results of surprising constancy. As introductory to the working of this apparatus, I will ask your permission to repeat the well-known experiment which proves that carbonic anhydride is one of the resulting products of alcoholic fermentation. [Experiment shown.] The two flasks which I have here, contain (represented in the diagram) equal (xuantities of the same sugar solution and of the 78 Mr. A. Gordon Sal ;Mavcli 29, Fi- 2. ' i \ 12 ^ - ~ 1 / — /" / / ^ / / / 55 Fermentative Activity of I BAKERS YEAST ALE DO PORTER DO y 7 ^ / / 1 A ^ - 1 // / // 1 f\ / \l / / 7 ~ 5 '// [/ / 7 In ?J / / -1- / / / 1 1 1 / / / S /' t 1 / 1 III \ X. u 5- ? A \^ y / ^ ;n s ^ y \ r\ c n ^S K *^ - 0* ^ ^ \ i \ s I - ^ s \ \ w 'QH I 13 d\ ;;"< w : isno N i '00. JO m yini 0A3 JO . JlVh ^ I % % i ' "c 5 ' L -. « s \t o 1889.] on Yeast. 579 nitrogenons material wliicli is best calculated to promote fermenta- tion. To each respectively has been added equal weights of two different kinds of yeast. To one has been added yeast used in the making of bread, and to the other that employed in the prodaction of porter. The temperature of the fermenting fluid has been the same in each case, likewise the time in uhich fermentation has been progressing. The two columns of coloured liquid were filled a short time previous to the commencement of the discourse, and the extent to which they have been respectively depressed is a measure of the amount of carbonic anhydride which has in each case been evolved in the same time. You will notice that there is a marked difference in the two results. The diagram of curves, which embodies the most typical of many experiments, and in which the abscissae have been determined by experiment, as shown, renders this difference clearly apparent. These results bring us to the heart of the question, and open up a vast field of inquiry, into which for lack of time we can this evening only travel a short distance. Granting that yeast is a plant — a fungus — may prompt the questions as to whether it be one genus, one species of a genus, or whether there be not many varieties of the species which can thus give rise to fermentations so difterent in character and vigour. To these questions the unrivalled researches of Hansen, of Copenhagen, have given an answer which leaves no room for hesitancy or doubt. The power of inciting alcoholic fermentation is not confined even to one genus of fungi, for, although it is essentially typical of the grouji known as the sprouting fungi, as opposed to the more widely distributed hypLal fungi, still it is true of many of the latter, and Brefeld has proved it to be the case with all the mucorini. It has been asserted, moreover, that some bacteria are capable of decomj)()sing sugar into alcohol and carbonic acid, thereby constituting themselves alcoholic ferments. This latter question, however, is one which demands further investigation. Before considering the morphological distinctions of the different species and varieties of yeast which have been thus isolated and examined, it is well to make ourselves acquainted with the nature and properties of yeast, the latter being now considered as constituting a generic term. [Various kinds of yeast, as employed in the arts, were shown, and their morphological peculiarities, as revealed by the microscope, demonstrated.] I am indebted to the great kindness of Dr. Hansen, which I desire most cordially to acknowledge, for preparations from pure cultures of all the species and varieties of yeast hitherto isolated. These I am enabled to render visible to you to-night, not in the form of drawings, but by means of lantern slides, which have been prepared by the skilled hands of Mr. Andrew Pringle from photographs which he himself took from the preparations furnished me by Dr. Hansen. [Slides exhibited, and the properties of the various specimens 580 Mr. A. Gordon Salamon on Yeast. [March 29, 1889. explained and discussed.] The method of obtaining pure cultures of yeast organisms, as devised and perfected by Dr. Hansen, was next dealt with, and its industrial importance demonstrated. A full description of the process and of the apparatus required will be found in the Cantor Lectures delivered before the Society of Arts (January- February 1888) by the author. [A. G. S.] INDEX TO VOLUMES I. TO XII. Abel, Sir F. A., Application of Science to Military Purposes, ii. 283; iii. . 243 ; of Electricity, v. 479. Explosions and their Military Applications, in. 438. Chemical History and Applica- tion of Gun-cotton, iv. 245. Substitutes for Gunpowder, iv. 616 ; VI. 517. Accidental Explosions, vii. 390. Detonating Agents, ix. 62. Dangerous Properties of Dusts, x. 88. Accidental Explosions by Non- explosive Liquids, xi. 218. Work of the Imperial Institute, XII. 99. Abney, Capt., Spectrum Analysis in the Infra Red of the Spectrum, x. 57. Sunlight Colours, xii. 61. Absorption of Heat, iv. 487,489. Absorption Spectra, ix, 204,493; x.250. Abyssinia, v. 404. Acetylene, iv. 18. Acids and Salts, iii. 234. Acoustic Experiments of M. Lissajous, II. 441. Acoustical Phenomena, viii. 536 ; of Gunpowder, &c. 546. Action at a Distance, vii. 44. Actonian Prize (1851), awarded to Wharton Jones, i. 54 ; (1858), Sub- ject announced, ii. 1 ; No Award, 526 ; (1865), awarded to G. Waring- ton, IV. 399; (1872) to Eev. G. Henslow, and to B. Thompson Lowne, vi. 561 ; (1879), to G. S. ' Boulger, ix. 283 ; (1886), to G. G. Stokes, XI. 376. Adams, J. C, on Orbit of Meteors, ix. 44. W. G., Researches on Selenium, VIII. 70 ; IX. 527. Magnetic Disturbance, Aurorse and Earth Currents, ix. 656. Aeby, C, Nervous Contraction, iv. 589, ^olian Harp, vii. 488. Aerial Echoes, viii. 556. Aeronautics and Flight, v. 94. Africa, North, Geology of, viii. 594. African Customs, ix. 391, 395. Agassiz, L., on Glaciers, viii. 239. Aggregation, Material, i, 254 ; its re- lation to Radiation, iv. 487. Agrarian Laws of Lycurgus, iv. 268. Ainger, Rev. Canon, True and False Humour in Literature (wo Abstract), xii. 446. Air, Estimation of Organic Matter in, III. 89 ; see Atmosphere. Thermometer, vi. 439, Airy, G, B., Total Eclipse of 1851, i. 62. Eclipse of Thales, &c. i. 243. Pendulum Experiments in Harton Colliery, ii, 1 7. on Solar Eclipse, vi, 292. Akkas, XII. 280. A*lbert Nyanza Lake discovered, iv. 503. Albert, Prince Consort, Present from, III. 163 ; Address respecting his De- cease, IV. 404, 418. Alcohol, Effect on Medusae, viii, 177. Alcohols, VIII. 92 ; of Paraffins, viii. 86 ; from Flint and Quartz, vii, 107. Alexandrian Museum and Libraries, x. 12. Alison, S, S., Auditory Phenomena, III. 63. Alizarine, vi. 120. Alkali Metals discovered, vi. 390. Allcroft, J. D., Donation, iv. 231. Allen, Grrant, Colour Sense in Insects, IX. 201. Ralph, Postal System, in. 459, Allman, G. J. A., Coral Islands, vii. 58. Allotropic Changes, i, 133, 201; xii. 367. Alloys, their uses, v. 335 ; properties, XII, 367. Alphabet, its Origin, vi, 464 ; Roman, Greek, and Phoenician, vi. 468. Alps, Geology of, i, 31 ; of Savoy, vi. 142 ; Pre-Miocene, vii. 455 ; Build- ing of the, XI. 53. Aluminium-Ethide and Methide, iv. 343, 582 INDEX Aluminium, Specimens exhibited, ii. 79, 85 ; XII. 464; Kev. J. Barlow on, 215; Sir H. Eoscoe on, xii. 451. America, North, Physical Geography, II. 167, 522. American Customs, ix. 392. . Organ, tii. 489. • Picture Writing, vi. 465. Ammonia, ii. 274; ix. 51. Compounds of Platinum, ti. 176. Ampere, A., on Electric Current?, tii. 49. Analytically formed Substances by the Body, IT. 568. Anatomical and Medical Knowledge of Ancient Eg\ pt, xi. 378. Anaxagoras's Philosophy, ti. 314. Anaximander's Philosophy, ti. 305. Anaximenes' Philosophy, ti. 307. Anchippodus described, tiii. 123. Andaman Islands, xii. 269. Andamanese, Tin. 638 ; xii. 271. Anderson, Charles, Decease of, it. 516 ; Prof. Faraday's Eemarks on, t. 206. W., Mechanical Properties of Cork, XI. 436. presents High Vacuum Pump, xii. 181 ; portrait of Mendcleef, xii. 403. Andes, IMincrals of, iii. 190. Andrews, T., Gaseous and Liquid States of Matter, ti. 356. Piesearches on Ozone, ti. 549; Gases, tiii. 662. Anglo-Saxon Conquest, ti. 116. Anliydrous Organic Acids, i. 239. Aniline, History of, iii. 475 ; it. 437 ; Till. 228. Anima Mundi, iv. 512. Animal Individuality, i. 184 ; Forms, 444 ; TII. 94; Excitability, x. 146. and Vegetable Kingdoms, Limits, I. 415 ; Tin. 28 ; Structure, 298. Life, Persistent Types of, in. 151 ; in the Deep Sea, 299'; ti. 72. Magnetism, xi. 25. Quinoidine, it. 567. Animals, Earliest Stages of their De- yelopment, iii. 315. intermediate between Birds and Keptiles, t. 278. in motion, x. 44. Annual Meetings (1851 et seq.) i. 61, &c. Ansdell, Gerard, Eesearches on Meteorites, xi. 541. Ansell's Detector of Fire Damp, tii. 399. Ansted, D. T., Mud Volcanoes and Petroleum, iv. 628. Antagonism, xii. 284. Antipyrine, xi. 460. Antiquity of Man, it. 38. Antozone, in. 70. Ants, HalDits of, Tin. 253 ; ix. 174. Apes, Anthropoid, n. 26 ; in. 16. Aphis, DcTelopment of, i. 11, 14; ii. 535. Appareil Paulin (Smoke Jacket), ti. 371. Appert's Mode of Preserving Food, ii. 77. Appunn's Keed Tonometer, ix. 538. Aquarium, n. 403. Aqueous Vapour, condensed and frozen, IT. 5 ; see Vapours. Aquileia, xii. 175. Arabia, Eastern and Central, it. 348. Arabic Philosophy, it. 506. Arago's Discovery in Induction, xi. 123. Architecture, its relations to Science, it. 124 ; ConstructiTG Principles of the Styles, 268. Architectural Designs, Logic of, ix. 89. Arctic and Sub- Arctic Life, viii. 378. Arn}ada, xii. 307. Armenia and Ararat, Tin. 349. Armstrong's Time-fuzes, in. 443. Gun, its Construction, in. 246; its Powers, 500 ; Gunpowder experi- ments, TI. 277. Arnold, M., Equality (no Abstract)^ vm. 510. Emerson {no Abstract), xi. 43. Art and Science, points of contact between, it. 9. ■ illustrated by Coins, it. 306. Education, it. 380. good Taste in, t. 376. Old and New, ti. 103, 534. Artificial Illumination, it. 16. Formation of Organic Substances, T. 378. Keproduction of Volcanic Eocks (in French), xii. 330. Artistic Judgment, Limits of, tii. 144. Ashby, J, E., Catalytic Action, n. 66, Asia Minor, a Fortnight in, tii. 1 17. Assyrian Excavations, n. 143. Astronomy and Photography, n. 462 ; XI. 104, 367 ; xii. 158. Astrophotographic Congress, xii. 158. Athletic Games and Greek Art, x. 272. Atlantic Telegraph, ii. 401 ; t. 45. Atlantic, Temperature of, Tn. 263. Atlantis, Theory of an, iii. 431. TO VOLS. I. TO xir. 58: Atmosphere, Eadiation through, iv. 4 ; its Opalescence, 651 ; its Transpar- ency and Opacity, yii. 169 ; in Rela- tion to Putrefaction and Infection, vnr. 6. Atmospheric Electricity, m. 277. Atomic Heats of Metuls, vi. 397. Weights, VI. 398. Atomicities of the Elements, iv. 275. Atoms, IX. 494 ; x. 185, 256, 259 ; their combining Power, iv. 401. Auditory Ph<-nomena, iii. 63. Aurorse, i. 275 ; in. 9 ; ix. 656. Austen, R, Godwin, Coal in South- eastern parts of England, ii. 511. Australians, viu. 603 ; Skulls, 612, 616 : Customs, ix. 392. Autotype Process in Photography, vii. 220.' Averroes' Philosophy, iv. 510. Avicennas Philosophy, iv. 507. Avrton, W. E., Mirror of Japan, ix. '25. Electric Railways, x. 66. Babylon and Nineveh. Discoveries at, I. 84 ; II. 143 ; iii. 536 ; iv. 335. Baeyer's Synthesis of Indigo, ix. 580, 585 Baily, Eclipse of Thales,i. 244 ; Baily's Beads, 64. Bain, A., Doctrine of the Correlation of Force in its Bearing on Mind, v. 157. Bain's Printing Telegraph, i. 353. Baker, B., Bridging the Firth of Fortli, XII. 142. S. W., Sources of Nile, iv. 492 ; Abyssinia, or Ethiopia, v. 404 ; Slave Tra'de on the White Nile, vii. 239. Baldry Property purchased, rv. 291. Balfour, B., Island of Socotra, x. 296. Ball, R. S., Distances of the Stars, ix. 514. Balloon Ascent, ii. 437. Scientific Experiments, iv. 65, 385. Bancroft on American Customs, ix. 394. Bank Notes, Manufacture of, ii. 263. Barlow, Rev. J., Silica, i. 422. Application of Chemistry to the Preservation of Food, ii. 72. Aluminium, ii. 215, Woody Fibre and Parchment Paper, ii. 409. Mineral Candles, &c. ii. 506. Logograph, viii. 502. Donations, iv. 153, 347, 516. Barlow, Rev. J., resigns the Secretary- ship, III. 290 ; Resolution thereon, 313 ; Letter from, 329. his Portrait presented, iii. 1 ; his Bust presented, vii. 339 ; Pedestal, VIII. 4. Mrs., Donation, iv. 177. Barometer, Cartesian, i. 426. Barrett, W. F., engaged as Assistant in the Laboratory, iv. 156 ; observations on Sounding and Sensitive Flames, V. 7, 9. Barrows, in Yorkshire, v. 78. Basedow (an Educator), viii. 460. Bastian, Dr., Observations on Bacteria, &c. VIII. 10. Batemau, J. F., Subwav to France, vi. 110. Bathurst, Earl, presents Bust of Wol- laston, IX. 250. Bazley, T., Plea for Cotton, in. 514. Beacon Lights and Fog Signals, xii. 425. Becquerel, E., Electrical Researches of, 1. 75, 338, 360 ; viii. 565 ; on Fluores- cence, III. 160 ; X. 210. Bedouins, vi. 90 ; x. 301. Beecher, Phloo;iston, vi. 317. Beethoven's Music Characterised, vii. 24. Keetroot (Vinasses), ix. 53. Bell, A. G., Speech (no Abstract), viii. 594. Telephone, viii. 503 ; presents Telephone, ix. 59 ; on Selenium, ix. 531 ; Experiments, x. 175. Jacob, presents Gould's Works on Bu-ds, III. 154. Messrs., present Seven Pounds of Sodium, IV. 153. Bell, Great, of Westminster, ii. 368. Bells, II. 384 ; ix. 99 ; Music of, 109. Belmontine, n. 507. Ben Doran (Poem), ix. 553. Benedict, Sir J., Weber and his Times, VII. 199. Bonnet's Experiment on the Impact of a Beam of Light, iv. 560. Benzene and its Derivatives, xi. 452. Benzol discovered by Faraday, in. 482 ; its relation to Mauve, 477. Berkeley's Philosophy, vi. 341. Bernouilli's Kinetic Theory, ix, 520. Berthelot discovers Acetylene, iv. 18. BerthoUet applies Chlorine to Bleach- ing, VI. 200. Bertin's Decomposition Apparatus pre- sented. IX. 359. Besant, W.. Art of Fiction, xi. 70. Bessel on 61 Cygni, ix. 514. 584 INDEX Besseraer's Steel, vni. 323. Bezold, Transmission by Nerves, iv. 585. Bicbat's View of tbe Nervous System, XT. 530. Bicycles, xi. 13. Bidwell, S., Selenium, ix. 52 1 ; Tele- pliotoo^rapby, 533. Bigsby, J. J., Lake Superior, i. 154. • Donation, iv. 243. " Big Tree,'" viii. 578. Biogenesis, viii. 20. Biot, Experiments of, v. 188. Birds, History of, viii. 347. Birks, Rev. T. R., Analogies of Pbysi- cal and Moral Science, vit. 12. Blackheatb Pebble-bed, i. 164. Blackie, J. S.. Spartan Constitution and Agrarian Laws of Lycurgas, iv. 203. Music of Speech, v. 145. Popular Myths, vi. 129. Pre-Socratic Philosophy, vi. 302. Modern Greek Language, vi. 4'J3. Language, &c., of Scottish High- lands, IX. 547. Blakeley's Gun, m. 246 Blasting Gelatine, ix. 75 of Coal or Rock, x. 110. Bleaching Powder invented, vi. 201. Blind, Education of the, i. 290 ; Rules for their Management, 297. i Blue Sky, x. 204. 206. Boileau, Sir J. P., Donation, iv. 153. Boiler presented, ix. 37. Boiling Water, Phenomena of, iv. 158. Bolometer, xi. 273. Bonelli's Electric Silk-Loom, iii. 272. Bonnev, T. G., Building of the Alps, XI. 53. Bonwick, J., on Tasmanians, viii. 621. Boscovich's Theory, vii. 49. i Botfield, R., Legacy from, iv. 326. ' Boulger, G. S., obtains Actonian Prize, IX. 2S3. Boussingaiilt's Mode of procuring Oxv- gen, I. 337. , ' < Boutignv, M., Etudes sur les corps a I'e'tat sphe'roidal, i. 179. Bowdich's Method of Purifying Coal I Gas, TV. 17. j Bowman, Sir W., presents ivory Bust \ of Faraday, viii. 508 ; elected Hon. Secretary, x. 14 ; resigns, xt. 285. Boys, C. v., Meters for Electricity, &c. X. 235. Bicycles and Tricycles, xi. 13. Quartz Fibres, xii. 547. Bradbury, H., Nature Printing, ii. 106. Bank Notes, ii. 263. Bradbury, H., Printing (no Ahstrarf) ii 534. Present from, ii. 147. Bradford, W., Greenland, vt. 377. Bradley, Rev. G. G., Westminster Abbey, xii. 217. Bradley's Determination of the Velocity of Light, VII. 472 ; Discoveries, &c., X. 117. Braid, Dr., on IMesmerism, xi. 26, 35. Brain of Man and Apes, iii. 407. its Unconscious Activity, v. 338. Surgery in the Stone Ages, xii. 72. Br.imwell, Sir F., Future of Steel, viii, 314. "Thunderer" Gun Explosion, ix. 221 ; Se.iuel to, 309. Channel Tunnel, x. 121. London (below bridge) N. and S. Communication, x. 483. A Lecture with, and without, point (no Ahdract), xii. 262. Donation, xi. 175. elected Hon. Secretarv, xi. 284. Brande, W. T., Peat, i. 4. Electro-magnetic Clocks, i. 109. Address on resigning his Professor- ship, I. 168 ; Report respecting, 170 ; elected Hon. Professor of Chemistry, 171 ; Decease, iv. 550. Branson, F., Nature-Printing, ii. 112. LJrazil, Emjieror of, elected Hon. Mem- ber, VI. :-'.84 ; Letter from, 422. Breail-making, iii. 253. BreeChloading Small Arms, v. 62. Brett, J. W., Submarine Telegraph, ii. 394. Brewster, Sir David, on the Mirror of Japan, ix. 27. Bridges, J. H., Influence of Civilisation upon Health, v. 470. Bridges, x. 485 ; xii. 142. Bri4:ain, Early Condition and Coinage, VII. 477. British Empire, ]\Iap and Statistics, XII. 99, 127. Seas, Natural History of, i. 17. Brixham Hill Cavern, iii. 149. Brockedon, W.. Caoutchouc, i. 42. Foreign Wines and the Fungus on the Grape, i. 303. Brodhurst, B. E., Donation, iv. 290. Brodie, B. C, Allotropic Changes, i. 201. Hydrogen and its Homologues, i. 325. Melting Points, i. 449. on Ozone, iii. 71 ; vi. 552. Brodrick, G. C, Land Systems, ix. 559. TO VOLS. T. TO Xn. 585 Bronze Age, iv. 32. Gun, its Sound, vni. 545. Brooke, C, Compound Achromatic Microscope, i. 402. Brookfield, W. H., Oral Eeading, iv. 241. Brou2:hton, J., engaged as Assistant in Laboratory, iv. 156. Brown, Crum, Chemical Constitution, T. 495. Browne, H. Crichton, In the Heart of the Atlas (Abstract deferred), xii. 409. Sir James Crichton, elected Treasurer, xn. 563. Browning, J., presents Electric Lamp, VII. 237. Oscar, History of Education, viii. 449. Briinnow on 61 Cygni, ix. 516. Brunton, T. Lauder, Element of Truth in Popular Beliefs, xii. 134. Bryce, J., Armenia and Ararat, vm. 349. Buchan, A., Weather and Health of London, ix. 629. Buclianan, Dugald, ix. 553. Buckland, Frank, Culture of Fish, iv. 75. Buckle, H. T., Influence of Women on the Progress of Knowledge, ii. 504. Budd, W., on the Germ Theory, vi. 369. Buddhism in India, iv. 136. Bunsen and KirchholTs Spectrum Ob- servations, in. 393, 396; vi. 390; IX. 500. and Schischkofi's Experiments on Gunpowder, vi. 275. Bun sen's Measurement of the Sun's Chemical Action, iv. 129 ; experi- ments on Dissociation, xi. 474. Burdett-Coutts Geological Scholarship, III. 264. Burgoyne, J. C, Donation, iv. 231. Busk, George, elected Treasurer, vii. 105 : resigns, xi. 468. Buys Ballot's Law, vii. 39. Bve-law suspended, JX. 156, 177 ; re- pealed or altered, v. 308 ; vm. 663. Cable-laying AprLiAxcES, vn. 310. Csesalpinus on the Heart, vin. 493. Caesium, iil 325 ; vi. 391 ; Spectrum, IX. 207. Cagniard de la Tour, discovered Yeast- plant, VI. 6; his Experiments on Liquids, VI. 357. Cailletei's Experiments on Liquefaction of Gases, vm. 662 ; xi. 148. Calcium, iii. 83 ; Spectrum, ix. 215. Calder, on Tasraanians, vm. 622. Calieo-Printing, iii. 201. Californian Forests, vm. 579. Calvert, F. C, Chevreul's Laws of Colours, iL 428. Influence of Science on Calico- Printing, iii. 201. Campbell- Johnston, P. F., presents Bust of Sir H. Davy, xn. 201. Canada, Geology of, ii. 522. Caudle-power of Electrical Machines, IX. 12. Candles, Manufacture of, i. 21; Mineral &c., n. 506. Cannani on the Heart, vm. 493. Cannon, Construction of, iii. 244. Canons, x. 268. Caoutchouc, i. 42 ; iii. 250. Capillary Attraction, xi. 483. Captain, Iron-plate Vessel, vi. 212. Carbon Compounds, Spectrum of, ix. 674, Carpenter, W. B., Influence of Sug- gestion on Muscular Movement, I. 147. Rhizopod type of Animal Life, Ii. 497. Relation of the Vital to the Physical Forces, iii. 206. Temperature and Life of the Deep Sea, V. 503; vl 63. Unconscious Activity of the Brain, V. 338. Mediterranean, vi. 236. " Challenger ' Expedition, and the Temperature of tlie Atlantic, VII. 263. Land and Sea in relation to Geo- logical Time, ix. 268. Carpmael, W., Manufacture of Candles, L 21. Carrick's Respirator, vi. 371. Carrington on Solar Eclipse, vl 286. Carruthers, W., Cryptogamic Forests of the Coal Period, v. 511. British Fossil Cycads (no Jbs- tract), XL 283. Castner's Aluminium and Sodium Process, xii. 451. Castor and Pollux, Minerals, vi. 392. Catacombs, Roman Art in, vu. 316. Catalogue of Library, n. 446 ; x. 169. Catalytic Action, ii. 66. Cattle of Britain, ii. 259. Cauchy's Colour Theory, x. 198, 202. Cavalli, Col., Fired Gunpowder, vi. 274, Cavendish Balance presented, v. 403. Experiment on Composition of Water, vi. 315 ; on the weight of the Earth, xn. 555. 586 Celtic Language, ix. 547. Centaurea, x. 158. Cerebral System of Classification, iii. 174. Cetacea, x. 360. Chalk, X. 123, 132. "Challenger" Expedition, vii. 263, 354 ; Researches, ix. 271, 274, 331. Chameleon, Mineral, iii. 89. Channel Tunnel, vi. 110; x. 121. Charcoal, a Sanitary Agent, ii. 53. Charlerois on Niagara, vii. 73. Chatelier's Mode of Arresting Railway Trains, ix. 316. Chaucer's Life and Works, ii. 248. Chemical Action of Solar Ravs. iii. 210 ; of Diflfubed Daylight, iv. 653. Actions, Rate of, v. 304. Affiaity, i. 416. Circulation in the Body, iv. 449. Constitution, v. 495 ; -viii. 351. Decomposition, viii. 179. Discoveries from the Great Exhi- bition, I. 131. Dynamics, i. 90. Forces connected with Tolarisa- tion of Light, i. 45. Properties of Compounds, i. 451. Rays and the Light of the Sky, V. 429. Chemistrj', Military, ii. 283 ; Agricul- tural, 289 : of Light, 223 ; see Su7i. of the Primeval Earth, v. 178. Newton's principles applied to, XII. 506. Chenot's Steel, vtii. 320. Chevreul, M., Laws of Colours, ii. 428. Children's Voltaic Battery, ix. 1. Chinese Lists of Meteors, in. 143. Library presented, iii. 219. Writing, vi. 466. " Elements," viii. 179. Customs, IX. 405. Chladni's Theory of Meteorites, xi. .332. Chlorate of Potash as a substitute for Gunpowder, iv. 617. Chloride of Lime invented, vi. 201. Chlorine, Manufacture, &c. vi. 199 ; xii. 455. Cholera : its Cause and Prevention, XI. 288. Chorley, H. F.. English Poetry with reference to Music, in. 317. Christian Belief shown in the Roman Catacombs, vii. 316. Christie, W. H. M.. Universal Time, XI. 387. Chromatic Phenomena, ii. 336. Chromium Spectrum, x. 246. Chronometry of Life, in. 117. Chronoscopes, iv. 577 ; used to measure Action of Gunpowder, vi. 278, Chrysalides, Gilded, xii. 33. City of London Records, xii. 28. Civilisation, its Influence on Health, v. 470. Clairaut's Instrument for Extracting Roots, VII. 189. Clark, Latimer, Electrical Quantity and Intensity, in. 337. Clark's Process of Purifying W^ater, n. 467. Classical Education, v. 30, 273. Classification of the Elements by the Atomicities, iv. 275. Cleavage of Rocks, &c. n. 298. Clermont, Lord, Presents Works of Sir J. Fortescue, vii. 330. Clitford, W. K., Mental Development, V. 3n. Physical Forces (no Abstract), vi. 83. Calculating Machines (no Abs- tract), VI. 533. Education of the People, vii. 314. Climate of London, ix. 631 ; in Town and Country, x. 17. Clothina:, Principle of, vi. 229. Cloud Observations, x. 332. Clubs, Australian, &c. vii. 513. Coal, Formation of, i. 284 ; in. 510 ; its Uses, V. 329 ; Contents, ix. 52 ; Supply, XII. 204. EniJflish, II. 59, 511 ; American, 181 ; Power of, 184. Period, v. 511. Coal-gas, Manufacture of, &c. i. 320 ; VI. 489. Coal-mines, Probable Exhaustion, v. 328. Explosions, vii. 396. Coal-tar Colours, History of, in. 468 ; XI. 450 ; Specimens of, 483. Industry, XI. 450 ; xii.107; Sources of Products, XI. 451 ; Colours, xi.454; XII. 108 ; Antipyretic Medicines, xi. 459 ; Aromatic Perfumes, xi. 462 ; Saccharine, xi. 462. Coast Defence, v. 550 ; of England, v. 458. Cobbold, T. S., Natural History Sciences (no Abstract), in. 243. Cobden Club presents its Publications, IX. 544. Cohn on Putrefaction and Bacteria, vin. 7. Coinage of Ancient Britons, vn. 476. TO VOLS. TO XII. 587 Coins, Representations on„iv. 306; x. 287, 291. Cold : its Production, and Effects on Microphytes, xi. 3u5. Coleman, J. J., Mechanical Production of Cold, XI. 305. Coleridge, S. T., xii. 233. Coles's Shield-vessel, iii. 509. CoUett, H., Donation, xii. 327. Colliery Explosions, x. 94 ; xii. 205. Colloids, III. 424 ; vi. 30 ; viii. 310. Colne River Water, ii. 49. Colonial Organisms, ix. 508. Colorado, Grand Canon of. x. 2G9. Colour Vision, vi. 260. Blindness, vi. 269 ; xii. 64. of Water, vi. 189. Senses in Insects, ix. 201. Colour of Bodies in relation to their state of Aggregation, iv. 489. Colours, XI. 107 ; xii. 61 ; Laws of, II. 428; the Three Primary, iii. 370 ; of Polarised Light, vii. 291 ; Refran- gibility, x. 196 ; of Thin Plates, xii. 81. Coloured Liquids, Action of Heat on, VII, 458. Colouring Matters, v. 566 ; ix. 57, 58. Columbus, Realdus, on the Heart, viii. 492. Colvin, S., Artistic Judgment, vii. 144. Combustion in Rarefied Air, iii. 331. Comenius, J. A. (an Educator), viii. 455. Comets, x. 1. Common, A. A., Photography as an Aid to Astronomy, xi. 367. Compass Deviations in Iron Ships, iv. 518. Composite Portraits, ix. 163. Compressed-air Propulsion, x. 138. Conolly, J., Condition of the Insane (no Abstract), i. 303 ; Characters of In- sanity, 375. Conservation of Force, ii. 352 ; viii. 217; and Organic Nature, iii. 347. Contact Electricity, x. 190, 195. Continents, Old, vii. 32. Conway, M. D., New England, v. 59. Emerson and his views of Nature, X. 217. Cook, Capt., on Australians, viii. 604 ; IX. 392; Tasmanians, 621 ; New Zealanders, 644 ; Marquesians, 649. Cookery, vi. 231 ; Military, ii. 422. Cope, E. D., Palseontological Dis- coveries, VIII. 103-124. Copper-Zinc Couple, vii. 521 ; viii. 182. Vol. xii. No. 83.) Coral Reefs and Islands, vii. 58 ; xii. 251. Cork, XI. 437 ; Applications of its Me- chanical Properties, 444. Cornu, A., Velocity of Liujht, vii. 472. Optical Study of the Elasticity of Solid Bodies, ix. 191. Corona, Solar, vi. 284, 484 ; xi. 202 ; Photographed, xi. 204. Correlation of Force in its Bearing on Mind, V. 157. Cottager's Stove, ii. 423. Cotton, Plea for, iii. 514. Wool Respirator, vi. 9. Cotyledons, xi. 517. Coulvier-Gravier, Meteors, iii. 145. Cowper, E., Lighthouses, i. 24 ; Locks (no Abstract), 163. Cox well's Balloon Ascents, iv. 71. Crimean Mud Volcanoes, iv. 628. Crisp, F., Ancient Microscopes {no Abs- tract), XII. 201, Critical Temperature and Pressures of various Substances, xi. 151. Crookes, W., Thallium, iv. 62 ; vi. 392. Mechanical Action of Light, viii. 44. Molecular Physics in High Vacua, IX. 138. — ^ Genesis of the Elements, xii. 37. Crossley, Messrs., present a Gas- engine, XII. 372. Cryptogamic Forests (Coal Period), v. 511. Crystal Molecule, iii. 95. Crystal Palace Fire, v. 18. Crystals, their Action on Polarised Light, VI. 506 ; Iridescent, xii. 447. Crvstallisation, xi. 508 ; of Metals, vi. 425. Crystallographic Models, iii. 86, 88. Crystalloids, iii. 424 ; vi. 30 ; viii. 310. Culture, Evolution of, vii. 496. Cuneiform Characters, early Use of, i, 84 ; Discovery, iii. 536 ; iv. 335. Cuvier on Discovery, ix. 22. Cyanogen Compounds, ix. 259. Flame Spectrum, ix. 679. Cycads, x. 221. Cyclones, Periodicity of, vii. 36. Daboll's Fog-horn, vii. 169, 173 ; xii. 441. Dallinger, W. H., Lowly Forms of Life, vni. 391. and Drysdale's Experiments on Monads, viii. 31. Dampier, on Australians, viii. 603 ; on American Customs, ix. 392. 2 R 588 INDEX Dana, J. D., on Land and Sea, tx. 276. Dannreuther, E., Music of the Future, YIT. 22. Dante, on, n. US. Darwin, C, on Glen Eoy, ym. 23S._ E. A., Donation, v. 549 ; vi. l0, 281. Gemmation, ir. 534. Generic Images, ix. 161. Geographical Circumstances and Poli- tical Character, viii. 529. Geological liesults of Challenger Expe- dition, VII. 354 ; IX. 268. Time, i. 287, 428 ; iii. 109 ; viii. 129; IX. 268. Geology of, the Alps, i. 31 ; Lake Su- perior, 154; London, 164; Ingle- borough, 278 ; Nova Scotia, 281 ; Isle of Wight, &c. 316 ; of tiie High- lands of Scotland, &c. xii. 528. Geranium, ix. 596. Gerhardt's Discovery of Anhydrous Or- ganic Acids, I. 239. German Gunpowder, iv. 617. Germ Theory of Disease, vi. 7 ; viii. 6, 15. Geysers of Iceland, i. 332. Gibbs, Mrs. J., Donation, xii. 526. Gibraltar Current, vi. 246; Geology, VIII. 594. Gill, D., Distance of the Fixed Stars, XI. 91. Applications of Photography in Astronomv, xii. 158. Gillett, W. S., Microscopes, i, 403-5. Gilman, on Solar Eclipse (1870) vi. 287. Glacial Epoch, iv. 166. Glaciers, ii. 320, 545 ; iii. 72, 269 ; vi. 155, 378. Gladstone, J. H., Chemical Affinity, I. 416. Gunpowder, ii. 99. Chromatic Phenomena by Trans- mitted Light, II. 336. Colours of Shooting Stars and Meteors, iii. 143. Fogs and Fog-signals, iv. 49. Light, V. 371. Crystallisation, vi. 425. Science in Elementary Schools, VII. 449. Copper-zinc Couple, vii. 521. Chemical Decomposition, vii. 179. Chemical Constitution and Ke- fraction of Light, viii. 351. elected FuUerian Professor of Chemistry, vii. 302. ■ Donation, iv. 1 56, Glaisher, J., Aerial Scientific Eesearch, IV. 65, 385. Glass Furnaces, in. 538. IManufacture, xi. 413. Fibres, viii. 61 ; xii. 549. Glen-Roy, Parallel Roa.ls of, in. 341 ; VIII. 233. GJyoxilin, ix. 78. Goethe, on Light, viii. 69. ' Farbenlehre,' ix. 340, Gold and Light, Relations of, n. 310, 444. Extraction of, from its Ores, i, 205 ; Large Nugget from California, 3. Goldfussia, x. 155. Good Shepherd in the Catacombs, vii. 322, 323. Goodenough, Captain, on Melanesians, viii. 630, 631, Gorilla, in. 10. Gosse, E., Leigh Hunt, xii. 409. Gothic Architecture, in. 32 ; ix. 95. Period of Art, vi. 56. Ornament, ix. 447. Graham. T., Researches on Dialysis, in. 422; Diffusion and Occlusion of Gases, V. 12, 159 ; Meteoric Iron, ix. 48. Life and Works, vi. 15. Grailich's Researches in Crystallo- graphy, in. 98. Gramme Electric Machine, ix. 12-14. Grand Canon District, x. 209. Grant, J., Military Cookery, n. 422. Cooking Apparatus, m, 251. Col. J. A., Donation, x, 214. R., Proper Motions of the Stars, X. 115. Grape-fungus, Oidium Tuckeri, i. 305. 594 INDEX Grapbite, xi. 545. Gratiolet's Kesearches on the Brain, III. 408. Grav, A., on N. American Flora, viii. 578. E., Telephone, viii. 503. Greek Art, x. 272 ; Painting, x, 292. Coins and Greek Art, it. 306. Mythology, vi. 129. Language, its Vitality, vi. 493 ; its Pronunciation, vi. 504; Music of Speech, v. 145. Greenland Flora, viii. 575. Green well, W., Yorkshire "Wold Tumuli, V. 78. Greg, W. R., Life at High- Pressure, VII. 368. Groombridge Star (1830), ix. 517; (1618) 518. Grove, Sir W. R.. Heating Effects of Electricity and Magnetism, i. 119. Transmission of Electricity by Flame and Gases, i. 359. Perpetual Motion, ii. 152. Molecular Impressions by Light and Electricity, ii. 458. Electrical Discharge in Rarefied Media, iii. 5. Boiling Water, iv. 158. Antagonism, xir. 284. presents Bust of Rev. J. Barlow, VII. 339. Donations, viii. 4 ; xi. 319. Grubb, H., Telescopic Objectives and Mirrors, xi. 413. Gull, W. W., Physiology of Voluntary Movement, i. 37. Gun-cotton, History, &c. iv. 245; vi. 518 ; vii. 413 ; ix. 62 ; Mechanical Nature, iii. 292 ; iv. improved, 622 ; its Application to Shells, vi. 519; Storage, VI. 531 ; vii. 423 ; ix. 77 ; Acoustic Powers, viii. 546, 547. ; Explosion, IX. 221, 309. Gunpowder and its Substitutes, ii. 99 ; IV. 616 ; VI. 517 ; vii. 415, 419. 424 ; IX. 72 ; X. 444. Tension of Fired, \i. 273 ; Acous- tic Power, viii. 546. Guthrie, F., Solid Water, viii. 302. Hales, Stephen, Evaporation of Plants, VII. 159. Halicarnassus, Discoveries at. in. 385. Haller, Nervous A^ent, iv. 577. Halley's Observations of Stars, x. 116. Hamilton, J. B., Wind applied to String Instruments, vii. 488. Hamilton, W. R., presents Lepsius' ' Egypt,' II. 414. Hamlet, on, v. 295. Hancock, 0. F., presents Littre''s Dic- tionnaire, vii. 30. Harconrt, A. Vernon, Rate at which Chemical Actions take place, v. 304. Coal Gas, vi. 489. Value of different Modes of Light- ing (920 Abstract), x. 120. Hartley, W. N., Action of Heat on coloured Liquids, vii. 458. Harton Colliery Experiments, ii. 17. Harvey, W. and his Discoveries, viii. 485. Haswell Collieries Explosion, x. 94. Haughton, S., Shot Drill Physiological Experiments, iv. 678. Haweis, Rev. H. R., Bells, ix. 99. Old Violins, 305. Hawk.^ley, C, Donation, viii. 589. Hawkyns, J. and the Armada, xii. 307. Health and Houses, iii. 133. Heart, vii. 214 ; viii. 485. Heat, Conduction of, i. 254. and Light, Analogies of, i. 172 ; VI. 417. Application of, to Cookery, ii. 422. in relation to Crystallography, III. 99 ; its Transmission through Gases, 155, 295. ■ of the Sun, iii. 531 ; xii. 1 ; of the Moon, VII. 139. of Oxyhydrogen Flame, v. 391. Rumford's Researches, vi. 231, 232 ; X. 445. (Atomic) of Metals, vi. 297. its Action on Coloured Liquids, VIII. 458. of Electric Light, ix. 2, 20, 21. Nature of, x. 253. Heath, V., Autotype Process, &c. vii. 220. Heating Effects of Electricity and Magnetism, i. 119. Heavenly Bodies, Spectrum Analysis applied to, v. 475. Hebrew Alphabet, vi. 470. Heliograjih, iii. 363. Helmholtz, H., Law of the Conserva- tion of Force applied to Organic Nature, in. 347 ; iv. 675. on Transmission by the Nerves, IV. 578 ; his Myographion, iv. 582 ; Fluorescence in the Human Eye, iv. 571 ; Conductivity of Heat by Metals, viii. 75. TO VOLS. I. TO XII. 595 Helps, T. W., Donations, iv. 516; v. 76,370,549; vi. 175,301. Henderson's Observations of Stars, xi. 95. Hennepin on Niagara, vii. 73. Henrici's Model of Peaucellier's Apparatus, vii. 190. Henry, Joseph, Eesearcbes on the Ley- den Jar, XTi. 418. Paul and Prosper, Astronomical Observations, xii. 162. • W. C, Donation, iv. 290. Henslow, Rev. G., obtains Actoniau Prize, VI. 561. Heraclitus's Philosophy, vi. 470. Heredity, Typical Laws of, viii. 282. Herschel, A. S., Luminous Meteors, &c. IV. 87. Shooting Stars, 1865-7, &c. iv. 645 ; V. 164. Eclipse of the Sun (wo Abstract), V. 450. on Star-grouping, vi. 143. Sir J., on Chemical Rays of Light, I. 259. Hertz's Researches, xii. 417. Heteromita, Monads, viii. 31. Hieroglyphical Researches, vi. 466 ; XI. 574. High Temperatures, ix. 257. Hill, M. D., Po.st-office, iii. 457. Hills, T. H., Donation, iv. 177. Hindu Law, ix. 540 ; x. 143. Hirsch, NervousAgent, iv. 586, 590, 592. History, Science of, iv. 180 ; Influence of the Imagination on, v. 394. Hochsfadter's Substitute for- Gun- powder, IV. 617. Hodgkin, T., Aquileia, the Precursor of Venice, xii. 175. Hodmadods (Hottentots), viii. 604. Hofmann, A. W., Ammonia, ii. 274. Mauve and Magenta, iii. 468. ■ Combining Power of Atoms, iv. 401. Holland, Sir H., Letter and Donations from, III. 107, 382, 526 ; iv. 177, 316, 464, 660; v. 186, 403, 451, 605; vi. 175, 364, .544; vii. 154; elected President, 434; Decease of, vii. 164; Resolution, 166: his " Fragmentary Papers " presented, 384. Sir H. T., Letter from, vii. 212. Holmes' Magneto-Electric Light Ap- paratus, in. 222; IV. 17; ix. 5, 11; XII. 437. Holtz Electrical Machine, xii. 302. Holy Sepulchre at Jerusalem, Site of, III. 426 ; IV. 366. Homeric Poems and Art, x. 275. Hooke, R., on Conduction' of Sound, VIII. 501. Hooker, Sir J. D., Distribution of North American Flora, viii. 568. Hooper, A., Donation, iv. 316. Hopkins, W., the Earth's Internal Temperature, &c. in. 139. Motion of Glaciers, iii. 410. Horizontal Shell-Firing, in. 504. Horsley and Ehrhardt, Substitutes for Gunpowder, iv. 617. Horsley, Victor, Motor Centres of the Brain, and the Mechanism of the Will, XI. 250. Brain Surgery in the Stone Ages, XII. 72, Horticulture by Electric Light, ix. 338. Hosking, W., Ventilation by the Parlour Fire, i. 76. Houses in relation to Health, in. 133. Hueffer, F., Musical Criticism, ix. 437. uggins, IV. 441. Spectrum Analysis of the Heavenly Bodies, v. 475. ■ Photographic Spectra of the ^ Stars, IX. 285. Comets, X. 1. Solar Corona, xi. 202. Hughes, D. E., Theory of Magnetism, XI. 1. T. McK., Geological Measures of Time, viii. 129. Human Proportion, x. 278. Humboldt on November Meteors, ix. 43. Hume on Shakspeare, ix. 597. Humphry, G. M', Sleep, vi. 424. Hunt, T. Sterry, Chemistry of the Primeval Earth, v. 178. Hunter's Theory respecting Rainfall and Sun Spots, viii. 424. Huntsman's Cast Steel, viii. 319. Huxlev, T. H., Animal Individuality, I. 184. Identity of Structure of Plants and Animals, i. 298. • Common Plan of Animal Forms, I. 444. Development of Animal Life in Time, ii. 82. Natural History, ii. 187. ■ our Knowledge of Nerve, ii. 432. Gemmation, ii. 534. Persistent Types of Animal Life, in. 151. Species and Races, in. 195. 596 INDEX Huxley, T. H., Earliest Stages in the Development of Animals, iii. 315. Fossil Eemains of Man, iii. 420. Methods and Kesults of Ethno- logy, IV. 461. Animal intermediate between Birds and Keptiles, v. 278. Pedigree of the Horse (no Abstract), vi. 129. Bp. Berkeley a,nd the Metaphysics of Sensation, vi. 341. ■ 'Challenger' Expedition and Geology, vii. 354. Border Territory between Animal and Vegetable Kingdoms, viii. 28. History of Birds, viii. 347. William Harvey, viii. 485. Structure of Sensiferous Organs', IX. 115. Coming of Age of the ' Origin of Species,' ix. 361. Oysters and Oyster Question, x. 336. elected Fullerian Professor of Physiology, n. 147; iv. 468. Hydration of Compounds, vi. 24. Hydrocarbons, ii. 63 ; viii. 86. Hydrocyanic Acid, ix. 257. Hydrogen and its Homolognes, i. 325. absorbed by Palladium, vi. 50. Hydrogenium alloyed with Palladium, VI. 54. Hylozoists, Philosophers, vi. 304. Hypnotism, xi. 26. Ice, Physical Properties of, ii. 454, 545 ; of Greenland, vi. 377. Iceland, Eruptive Phenomena of, i. 329. Iguanodon, Structure of, i. 141. Illumination, Artificial, iv. 16. by Chemical Light, i. 319. Imagination, its influence on History, v."394. Imitation and Copying, vi. 536. Imperial Institute, xii. 99 ; Subscrip- tions for, XII. 73. Indian Mythologv and Temples, vii. 67. Famines, viii. 407. Vegetable Food, viii. 421. Customs, TX. 399. India-Rubber, Properties and Applica- tions of, I. 42 ; III. 250. Indigo, IX. 580 ; Artificial, xi. 459. Indium, Discovery of, iv. 284 ; vi. 393. Individuality, Animal, i. 184, 193. Indophenol, xi. 457. Induction, xi. 119, Induction Coil Exj^eriments, viii. 359. Ingleborough, Geological Sketches round, i. 278. Insanity, Characters of, i. 375. Insects, Metamorphoses of, iii. 375 ; IV. 551. and Wild Flowers, vii. 351. Insect-catching Plants, vn. 332 ; x. 147, 159. Instinct, Tiieory of, xi. 131. Integrators, x. 237. Invisible Rays, Combustion by, iv. 329. Iritlescent Crystals, xii. 447. Irish Land System, ix, 572 ; Tenants, IX. 567. Iron, Manufacture of, i. 434 ; viii. 315; XII. 103. and its Resistance lo Projectiles, III. 491, 500. Walls of England, iii. 503. Age, IV. 33. Smelting, Chemistry of, vii. 264. Spectrum, x. 246. Ironclad Ships, vi. 95. Italian Art, vi. 56. Rivers, vi. 59. Jablochkoff Candle, ix. 17. Jacquard Loom, iii. 271. James, Sir H., Ordnance Survey, ii. 516 ; of Jerusalem, iv. 526. Jamieson, T. F., on Glen Roy, viii. 244. Japanese Art, iv. 99; Myths, ix. 26; Mirrors, 25. Jekyll, E., Siege Operations, ii. 42. Jenkiii, H. C. Fleemiug, Submarine Cables, v. 574. Jerusalem, Discoveries at, &c. iv. 23, 366, 526. Jervois, W. F. D., Coast Defences of England, v. 458. Detensive Poliey, vi. 335. Jesuit Education, viii. 4.^6. Jetoline, Marking Ink, viii. 229. Jevons, AV. S., Exhaustion of our Coal Mines, v. 328. Johnston, H. H,, Kilima-njaro (no Abstract), x. 469. Jones, H. B., AA ines, i. 381. Ventilation, ii. 236. ■ Chemical Circulation in the Body, IV. 449. Existence in the Textures of Animals of a Fluorescent Substance re.sembliug Quinine, iv. 564. TO VOLS. I. TO xir. 597 Jones, H. B., elected Hon. Secretary, iii. 293 ; Donations, iv. 177, 372 ; testi- monial to (a Bust) ; resigned, vii. 57, 58 ; Letter from, 92 ; Decease of ; Eesolutioii, 116 ; Letter from Lady Millicent, 153. T. Wharton, obtains Actonian Prize, I. 54 ; elected Fullerian Pro- fessor of Physiology, i. 101. Joule, J. S., Researches on Heat, ii. 202 ; on Meteorites, xi. 333. Jom-dan, C, Geometrical Discovery, VII. 196. Judd, J. W., Krakatoa, xi. 85. Julien on Magic Mirrors, ix. 28. Justice, Early Civil, ix. 540. Kairixe, XI. 460. Kars, Siege of, ii. 246. Katherine, St., Convent, vi. 86. Kent's Cavern described, iv. 534. Kent, T. J., Donation, iv. 323. Kerguelen Expedition, viii. 81. Kew Observatory, its Work, iv. 58. Kieselguhr, vi. 523 ; ix. 70. Kilburn, E., presents Thermopile, &c., viii. 251. Kinematical Paradox, vii. 192-4. Kinetic Theory, ix. 138; x. 211. King, The, in his relation to Early Civil Justice, ix. 540. Kirchotf's Spectrum Observations, iii. 233, 395. Kitchen Boiler Explosions, vii. 396. Klein, E. E., Etiology of Scarlet Fever, XII. 1,50. Knoblauch's Researches on Heat, i. 178. Koch's, Dr., Cholera Investigations, xi. 300. Koenig's Tuning-fork Clock, ix. 539. Koh-i-nur Diamond, iii. 231. Koppen on Weather Variations, vii. 35. Krakatoa, xi. 85. Krupp's Steel, viii. 320. Kundt on Absorption Spectra, ix. 501. Kustarnoe Industry, x. 359. Kyhl, P., on Nature-Printing, ii. 110. Laboratory of Royal Institution, As- sistants engaged, IV. 156; recent Re- searches in, see Faraday, FranMancl, Tyndall; Old and New, vii. 1, 10; Donations to New, vii. 92. Lacaita, J. P., Dante, ii. 118. Earthquakes in Southern Italy, II. 528. Ladd, W., presents Dynamo-Magneto- Electric Machine, ix. 672. Lainsou, H., Donation, iv. 243. Lake-Habitations of Switzerland, IV. 29. Lake Superior described, i. 154. Lament, Magnetic Variation, i. 238. Lamp Explosions, xi. 230. Lamy discovers Thallium, vi. 392. Land and Sea, ix. 268. Systems, ix. 559. Landlord and Tenant, ix. 567. Langley, J. N., Physiological Aspect of Mesmerism, xi. 25. S. P., Sunlight and the Earth's Atmosphere, xi. 265. Language and Implements, vii. 498. Curtailment, vi. 497 ; Increment, 499. Lankester, E., Limits of the Vegetable and Animal Kingdoms, i. 415. Drinking Waters of the Metro- polis, II. 466. Bread-making, iii. 253. E. Ray, Marine Biological La- boratory, XI. 215. Lantern of Lighthouses, vi. 219; xii. 435. Laughton, J. K., Invincible Armada, XII. 307. Lauren tian Rocks, iv. 374. Lava, Consolidation of, iii. 125. Lavoisier on Composition of Water, vi. 315 ; refutes the Phlogiston Theory, VI. 317. Lawrence, Lord, Early Life in India, X. 183. Lazy Tongs explained, vii. 182. Leaves, Forms of, xi. 197. Lecky, W. E. H., Influence of the Imagination on History, v. 394. Leconte, on Sensitive Flames, v. 6. Lectures, Courses (1851 et seq.), i. 29, &c. Legacies, R. Horsmon Solly, ii. 526; Beriah Botfield, iv. 326; George Dodii, 346 ; Alfred Davis, vi. 183. Leighton, J., Japanese Art, iv. 99. Lenk's Improvements in Gun-cotton, IV. 246, 296, 622. Leopold, Prmce, elected Honorary Member, ix. 283, 328. Leslie, H., Social Influence of Music, VI. 432. J., Researches on Heat, x. 253. Lewes, G. H., on Dust and Disease, vi. 366. Ley, W. C, on Winds, vii. 40; on Cloud Observations, x. 332. Leyden Battery. Currents of, ii. 132. Leyden Jar Discharge, xii. 413. Library, Time of Admission to, en- larged, and Assistant in, provided, i. 89. 598 INDEX Library Catalogue, ii. 446 ; x. 169. Lick Observatory, xi. 429. Liebig, J., on Source of Muscular Power, IV. 661. and Wohler, x. 477. Liebreich, R., Faults of Vision, vi. 450. Portraiture, vii. 430. Deterioration of Oil Paintings, viii. 514. Life, Chronometry of, iii. 117. at High Pressure, vii. 368. Light and Heat, Analogies of, i. 172. Change of Refrangibility of, i. 259. Chemical Action of, ii. 223, Relations of Gold to, ii. 310, 444. Chromatic Phenomena from Transmitted, ii. 836. in relation to Crystals, iii. 95. Experiments on, t. 371. Source of, in Flames, v. 419. of the Sky, v. 429. its Chemical Properties, vi. 232. Scattering of, vi. 189. Successive Polarisation, vi. 205. Identity of, and Heat, ti. 417. Physiological Action of, vii. 360 ; Till. 137. Velocity of. Tin. 472. Meclianical Action of, \ui. 44. ■ Action of, on Selenium, viii. 68. Electric, ix. 1. as an Analytic Agent, xii. 83. Lightfoot's Experiments with Aniline. viii. 228. Lighthouse Illumination, in. 220 ; ix. 5, 6, 11, 12 ; XII. 435. Lighthouses, their Construction and mode of Lighting, i. 24 ; Bishop Rock, XII. 429 ; Wolf Rock, yi. 214. Light-vessels, xii. 431. Lindsay, Lord, presents a Spectroscope, Yi. 379. Lines of Force, i. 105, 216, 229 ; vii. 50. Linton, R., Decease of, vni. 186. Liquefaction of Gases, vni. 657; xi. 148. Liquid Films, x. 192 ; xi. 243. Liquids, Motion of, i. 446 ; Ti. 26 ; Diffusion, vi. 28. Lissajous' Acoustic Experiments, ii. 441. Lister, Sir J., on Germs in Disease, vi. 8 ; Respired Air, viii. 7. Lithium, ni. 84 ; its Circulation in the Human Body, iv. 452 ; Spectrum, x. 247. Lithofracteur, its Properties, vi. 523. Liveing, G. D., Ultra Violet Spectra of the Elements, x. 245. Living Contagia, xi. 161. Lizards, Pineal Eye in, xn 22. Lochaber, Parallel Roads of, in. 341. Locke, J., on Qualities of IVlatter, vi. 345 ; Education, viii. 457. Locks, Improvements in, ii. 475. Lockver, J. Norman, Solar Physics, v. 580. Solar Eclipse (1870), vi. 284 ; (1871), 477. on Spectra, ix. 506, note ; sugges- tions, 292. Lodge, Oliver, Electrical Deposition of Dust and Smoke, xi. 520. Discharge of a Leyden Jar,xii.413. Logograph, viii. 502. Lombardic Period of Art, vi. 57. London, North and South Communica- tion, X. 483. Bridge Traffic, x. 500, 504. Weather and Health, ix. 629. Lontin Electric Machine, ix. 14. Louis of Hesse, Prince, elected Hono- rary Member, iv. 141, 151. Lowne, B. Thompson, obtains Actonian Prize, VI. 561. Lubbock, Sir John, Lake-Habitations of Switzerland, iv. 29. Metamorphoses of Insects, iv. 551. Wild Flowers and Insects, vii. 351. Habits of Ants, viii. 253 ; ix. 174. Fruits and Seeds, ix. 595. Forms of Leaves, xi. 197. of Seedlings, xi. 517. Luminous Phenomena, ix. 142. Lycurgus' Agrarian Laws, iv. 268. Lyell, Sir C, Impressions of Raindrops in Strata, i. 50. Blackheath Pebble-bed, i. 164. Discoveries in the Coal Measures of Nova Scotia, i. 281 ; Geological Time, 287. Erratic Blocks in Massachusetts, n. 86. Temple of Serapis, ii. 207. Conical Form of Volcanoes, &c., III. 125. on Land and Sea, ix. 269. Lyon, E. D., Indian Mythology and 'Temples, vii. 67. Macalister, a.. Anatomical and Medi- cal Knowledge of Ancient Egypt, xi. 378. Macfarren, G. A., Music of the Church of England, iv. 594. TO VOLS. I. TO XII. 699 Mcintosh, W. C, Life-History of a Marine Food-Fish, xii. 384, Maclntyre, ix. 558. McKendrick, J. G., Physiological Action of Light, vii. 360 ;' viii. 137. ■ Physiological Action of Anaesthe- tics ^no Abstract), ix. 171. The Breathing of Fishes (no Abstract), x. 27. Effects of Cold on Microphytes, XI. 305. elected Fullerian Professor of Physiology, ix. 712. ^Mackenzie, H., Donations, iv. 177, 435, 549. Macnaught, Rev. J., Donations, xii. 181, 565. Macquer on Phlogiston Theory, vi. 324. Madler on Solar Eclipse, yi. 293. Magenta, History of, iii. 468, 478; Specimens, 483 ; its Derivatives, iv. 437. Magic Mirrors, ix. 25 ; Property, 27. Magnesium, iii. 82 ; presented, iv. 151 ; Liglit, 489 ; Spectrum, ix. 209, 686 ; X. 246, 249. Magnetic Characters of Oxygen and Nitrogen, i. 1. Force, Lines of, i. 105, 216, 229 ; VII. 50 ; Influence of Material Aggre- gation on, I. 254 ; its Influence on the Electric Discharge, iii. 169. Hypotheses, i. 457. Disturbances, iv. 55 ; ix. 656. Experiment, iv. 317. Relations of Crystals, in. 98. Magnetisation of Iron, Effects of Stress upon, Yiii. 591. Magnetism, ii. 6, 13, 159, 196, 352. Atmospheric, i. 56. Heating eflects of, i. 119. Theory of, xi. 1. Magneto-Electric Machine presented, Y. 1 ; Light, IX. 5. Clock presented, vii. 30. Induction, xi. 119. Magneto-Electricity applied to Light- houses, in. 222 ; xii. 437. Magnets — Hascker's, i. 28 ; Logeman's, 37, 230. Magnus, Rotatory Motion, i. 395. Maine, Sir H. S., Feudal Property in England and France, viii. 126. The King and Early Civil Justice, IX. 540. Sacred Laws of the Hindus, x. 143. Majendie, V. D., Breechloading Small Fire-arms, v. 62. Malay I>lands, ix. 273. Malayo-Polynesians. viii. 643. Malays, viii. 640. Malone, T. A., Photogalvanography, ii. 343. Malvern Hills, ii. 386. Mammalia, Geographical Distribution of. III. 109; Cerebral System of Classification, 174. Man, as distinguished from Apes by his Structure, in. 15 ; by his Brain, 407 ; Fossil Remains of, 420 ; Early Mental Condition, v. 83. Manchester Steam Users Association Report, vii. 393. Manganese in Cldorine Manufacture, VI. 202 ; xn. 455. Mann, Mrs. R. J., Donation, xn. 376. Manning, Abp., Daemon of Socrates, vi. 402. Mantell, G. A., Tguanodon, and Fauna and Flora of the Wealden Forma- tion, 1. 141. Maoris, vni. 647. Marc-Aurele, ix. 369. " Maria Lee " Explosion, vii. 406. Marignac investigates Ozone, vi. 547. Marine Biological Laboratory, xi. 215. Food-Fish, xn. 384. JMarsh, 0. C, Palaeontological Dis- coveries, VIII. 103, 125. Marshall, J., elected Fullerian Pro- fessor of Physiology, in. 526. Proportions of Human Figure (wo Abstract), ix. 282. Martini-Henry Rifle, Experiments, ix. 74. Marx's Observations, ix. 415. Masai Land, xn. 199. Mascart, E., Sur les Couleurs, xi. 107. Maskelyne, N. S., Connection of Chemical Forces with the Polarisa- tion of Light, I. 45. Crystal Molecule, in. 95. Diamonds, in. 229. Meteoric Stones, vi. 513, Massachusetts Erratic BLx-ks, n. SQ. Masters, M. T., Plants, in. 223. Material Aggregation, i. 254. Material Medium in Space, iv. 558. Matter, Graham on its Constitution, vi. 43. Gaseous and Liquid States of, vi. 356. and Ether, viii. 335. and Magneto-Electric Action, x. 75. Matthiesen, A., Alloys and their Uses, V. 335. 600 INDEX Maurice, F. D., Milton as a School- master, n. 328. Mausoleum at Halicamassus, in. 384. Mauve, its Chemical History, ni. 4:6S ; IT. 438. MaxweU, J. C, Theory of Three Primary Colours, in. 370. Colo'ur Vision, vi. 260. Action at a Distance, vn. 44. • Kemarks on the Molecular Theory of Gases, ix. 504, 506. Mayer's Kesearches on Heat, Force, &C. ni. 534 ; iv. 663. Mayo, T., Kelations of the Public to the Science and Practice of Medicine, III. 258. Mayow, M. W., Hamlet, v. 295. Measurements, Personal, xn. 346. ;Mechanism of the Will, xi. 250. Mediterranean Sea, vi. 236-259; vni. 597. Medusa aurita, Development of, i. 11. Medusa, Nervous System, vni. 166, 438. Melanesians, viii. 629. Melde's Experiments on the Vibration of Strings, iv. 687. Meldrum on Cyclones, vn. 36, 43. ISIelloni's Investigations on Heat, x. 255. Mellor, S., on Va^nadium, vin. 229. Melting Points of Sulphur, i. 449. Memories Blended, ix. 161. Men of Science, vn. 227. Mendeleef, D., Attempt to apply to Chemistry one of Newton's Prin- ciples, xn. 506. Mental Development, v. 311 ; Images, IX. 644. Diflerences between Men and Women, xn. 78. Mer-de-Glace, n. 545. Mercer's Contraction of Cotton by Al- kalies, I. 134. Mercuric Fulminate, ix. 62, 64. Meritens Machine, ex. 15; presented, 170. Merrifield, C. W., Sea Waves, vn. 297. " Merrimac " described, in. 508. Mesmerism, xi. 25. Metals, Ancient and Modem, n. 215 ; History of, vi. 3S7 ; Precipitation of, m. 81 : Occlusion of Gases by, v. 159 ; their Atomic Heat, vi. 397 ; Crystallisation of, 425 ; Properties of, XI. 395 ; xn. 367. Metamorphoses and Metageneses of Animals, i. 9 ; rv. 551. of Insects, m. 375. Meteoric Stones, vi. 513 : Showers, ix. 41. Meteorites, x. 6 ; xi. 328 ; xn. 18. and the History of Stellar Systems, xn. 379. Meteorological Office, Work of, v. 535. Telegraphy, in. 444. Meteorology, x. 323. of Torquay, n. 437. Meteors, m. 143, 531 ; iv. 87, 644 ; ix. 40. Meters for Electricity, »tc.-x. 235. Methyl Chloride, ix. 54, 57. Metropolitan Water Supply, v. 346. Mexican Picture Writing, vi. 465. Mever's Experiments on Dissociation, XI. 476. Michael Angelo characterised, vi. 537. Michael's Mount, St., v. 128. Microscopes, Construction of, i. 402. Microscopic Research, vni. 393. Military Chemistry, n. 283 ; Cookerv, 422. Miller, W. A., Photographic Trans- parency of Bodies, and Photographic Spectra of Elementary Bodies, iv. -12. Stellar Spectrum Observations, IV. 442 ; IX. 286. Milne-Home, D., on Glen Eoy, vni. 237. Milnes, E. Monckton, International Exliibition of 1862, in. 485. Milton as a Schoolmaster, ii. 328 ; on Education, vni. 457. Mimosa, x. 152. IMimulas, x. 155. Mind and the Correlation of Force, v. 157. Minerals, Experiments with, ix. 150. of the Andes, ni. 190. Mining Districts of N. England, n. 57. Miocene Epoch described, vn. 282. Mirage, i. 67. Mirrors, Figuring of Plane, xi. 429. Mitchell, A., on Weather and Health, IX. 629. W., CrystaUography, in. 86. Solidified Sidphuric Acid, vni. 658. Mohammedan Mahdis, xi. 147. Molecular Phvsics, iv. 233; in High Vacua, IX. 138, 432. Molecule of Water, ia'. 118. Molecules, ix. 494; x. 185, 256, 259. Monads, vin. 31, 396. Moncrieff, A., MoncriefiTs System of Artillery, v. 550. Mond, L., Donations, xn. 178, 370, 526. '- Monitor " described, ni. 509. Monuments in Westminster Abbey, iv. 602. TO VOLS. I. TO XII. 601 Moon's Surface, Physical Aspects of, IV. 300. Moon, Radiiition of Heat from the, vn. i:;9. Moore, Miss H., Donations, it. 156, 328. Miss J., Donation, iv. 156. J. Carrick, Donations, iv. 177, 435, 516 ; V. 76, 276, 605. Mrs. B., Donation, xn. 376. Moral and Physical Science Analogies, VII. 12. More, H., Observations on Man, n. 26, 41. Morley, J., Influence of Rousseau, vi. 475. INIortality, ix. 629. Moscrop, E. H., Donation, v. 24. Moseley, H., Desceut of Glaciers,vi. 155. H. X., Deep-Sea Dredging, ix. 331. • Fauna of the Sea-shore, xi. 168. Motion in Plants and Animals, iii, 433. Mechanical Conversion of, vii. 179. Fluid and Vortex, vin. 272. of Water, xi. 44. Sound and Lieht, xi. 178, 179. Motive Power, ii. 152, 199. Motor Centres of the Brain, xi. 250. Moulton, J. F., Modern Scientific Theories, vin. 216. flatter and Ether, viii. 335. Researches on Electric Discharge, IX. 427. Mount of the Law, its position, vi. 93. Mountain Chains, Origin of, vii. 281. Movement, Voluntarv, Phvsiology of, I. 37, 147 ; of Plants, ix. o97. Mud Volcanoes and Petroleum, rv. 629. Muir, on Sequoias, viii. 579. Miiller, F. Max, Vedas, iv. 135. Migration of Fables, vi. 173. My'thology (jio Abstract), vi. 300. Rammohun Roy. x. 470. Hugo, Chemical Discoveries, ii. 506, 508. Mulready's Pictures affected by Faulty Vision, VI. 462. Munk, H., Researches on Transmission by Nerves, iv. 585. Murchison, Sir R. I., Changes of the Alps, I. 31. Donations, iv. 108, 316. Murray, A., Donations, iv. 372, 549. John, Coral Reefs and Islands, XII. 251. R., Sets up Penny Post, iii. 458. Muscle-Contraction, x. 149. Muscular Power, Source of. iv. 661. 3Iusic and English Poetry, iii. 317. of the Church of England, iv. 594. of Speech in Greek and Latin Languages, v. 145. its Social Influence, vi. 432. of the Future, vii. 22. Musical Criticism, ix. 437. Pitch, IX. 536. Muybridge, E., Attitude of Animals in Motion, X. 44. Science of Animal Locomotion in its relation to design in Art, xii. 441. Myographiou, iv. 582, 5S3. Myths, Interpretation of, vi. 129. Nasmyth, J., Physical Aspects of the Moon's Surface, rv. 300. Native Races of Pacific Ocean, vm. 602. Natural Selection and Ancient British Coinage, vii. 482. Nature-Printing, ii. 106. Naval Purposes, Electricity applied to, V. 479. Naville's Discoveries in Egypt, xi. 384. Nebulae, their Constitution, rv. 441. Negritos. Tin. 638. Nerve-centres, iv. 207. Function, x. 147. ;S"erves, n. 432 : viii. 427 ; their Nu- trition and Reparation, iii. 378 ; Time required for Transmission by, IV. 575. Nervous Agent, rv. 576. Systems, xi. 530. Neumann's Experiments with Gun- powder, VI. 275. New Bond Street, No. 166, purchased, IV. 291. Cidedonians, vin. 629. England, v. 59. Hebrides, vm. 630. Ireland Paddles, vn. 516. Zealand, Earthquake at, n, 213. Zealanders, vin. 646. Newton, Sir Isaac, on Gravitation, i. 237 ; Action iit a Distance, vii. 47 ; Sensation, ix. 116 ; Account of the Prism, IX. 349; Theory of Colours, IX. 351 ; Rings, x. 189 ; his principles applied to Chemistry, xii. 506. C. T., Mausoleum of Halicarnas- sus, HI. 384. Discoveries at Olympia, vm. 214. ■ at Pergamus {no Abstract), XI. 217. H. A., on Orbit ot Meteors, ix. 43. Niagara, vii. 73. Nicol's Prisms, x. 205, 207 ; xii. 480. GO: INDEX Nile, Sources of, iv. 492. Nitrates, vii. 418; ix. 203. Nitrogen, its Magnetic Character, i. 2. Nitro-elycerine, iv. G20 ; vi. 522 ; ix. 62, 79. Noad, H. M., Manufacture of Iron, i. 434. Nobel, A., on Nitro-glycerine, iv, 620 ; Ti. 522 ; Explo>ives, ix. 62. Noble, Captain A., Tension of Fired Gunpowder, vi. 273. Ciironoscope, ix. 64, 78, 231. Nordenskiold, A. E., Experiments with Bare Earths, xii. 48. North, Jolm, Donation, iv. 231. Northern Plants, Distribution, iii. 431. Northumberland, Duke of, the Presi- dent, Decease of, iv. 356, 372. elected President, vii. 167 ; pre- sents Engine and Machine, ix. 170 ; defrays cost of accumulators for electric lighting, xi. 321. November Meteors, ix. 40. Oaths, viii. 156. Objectives, xi. 413; Calculation of Curves, 415 ; Measurt-ment of Curves, 418 ; Flexure, 419 ; Polish- ing, 421 ; Figuring and Testing, 424. Occlusion of Gases by Metals, v. 159. Oceania, viii. 602. Oceanic Circulation Illustrated, vr. 252. Odliug, W., Hydro-carbons, ii. 63. Magnesium, &c. iii. 80. Acids and Salts, iii. 234. Graham's Researches, Dialy>i.>, III. 422; Diffusion of Gases, v. 12; Scientific Work, vi. 15. Molecule of Water, iv. 118. Aluminium Ethide and Methide, IV. 343. . Occlusion of Gases by Metals, v. 159. Heat of the Oxyhydrogen Flame, v. 391. Simplest Organic Compounds, v. 598. Ammonia Compounds of Plati- num. VI. 176. Manufactui-e of Chlorine, vi. 199. Revived Theory of Phlogistoo, VI. 315. Indium, vi. 386. History of Ozone, vi. 546. Evaporation and Diffusion, vii. 155. Paraffins and their Alcohols, viii. 86. Gallium (710 Ahstrart), viii. 513. Odling, W., Sir B. C. Rrodie's Re- searches on Chemical Allotropy (no Abdmct), X. 28. Dissolved Oxygen of Water (no Abstract), xi. 90. Elected FuUerian Professor of Chemistry, v. 424 ; re-elected, vi. 381 ; resumed, vii. 162. Ocrstedt on Electric Currents, vii. 49. Oil Paintings, Deterioration, viii. 514. Old Continents, vii. 32. Oliver, D., Distribution of Northern Plants, III. 431. Olyinpia, Discoveries at, viii. 214. Olympian Games, x. 279. Oolitic Forms of Vegetation, x. 220. Opalescence of the Atmosphere, iv. 651 . Optical Study of the Elasticity of Solid Bodies, ix. 191. Glass, Testing, xi. 413. Properties of Oxygen and Ozone, XII. 468. Torque, xii. 474. Oral Reading, iv. 242. Oran Eclipse Expedition, vi. 189. Ordeals, viii. 153. Orbits of Meteurs, ix. 43. Ordnance Survey, 11. 516 ; of Jerusalem, IV. 526. Organic Bodies, Production of, 11. 538 ; detected bv their Optical Properties, IV. 223. Chemistrv in Roval Institution, iv. 309. 465; Organic Synthesis, 199. Compounds, Simplest, v. 598. Matter in the Air, vi. 2. ' Origin of Species,' Coming of Age, IX. 361. Ornament, ix. 440. Osmose, vi. 32. Otto Gas-engine presented, ix. 170. Bicycle, xi. 23. Ou-tseu-hing on ]\Iirrcrs of Japan, ix. 28. Overstone, Lord, presents a Collection of Tracts, iii. 218. Owen, R., Metamorphosis and Meta- genesis, I. 9. Structure and Homologies of Teeth, i. 365. Anthropoid Apes, and their Rela- tions to Man. II. 26. Ruminant Quadrupeds, 11. 256. Gorilla, iii. 10. Succession in Time and Geo- graphical Distribution of Mammalia, III. 109. Cerebral Classification of Mam- malia, III. 174. TO VOLS. I. TO XII. 603 Owen, R., National Museum of Natural History (no Abstract), iii. 360. elected Fullerian Professor of Physiology, ii. 561. Oxygen, its Magnetic Character, i. 1 ; Boussinganlt's Mode of preparing, 337; Liquefied, xi. 148; Solidified, XI. 550 ; Oxygen and Ozone, Optical Properties, xii. 468. Oxyhydrogen Flame, Heat of, v. 391. Oysters and the Oyster Question, x. 336. Ozone, I. 94 ; vi. 546 ; xii. 468, 557 ; and Antozone, iii. 70. Pacific Ocean, Native Races, tiii. 612. Packe, E., Donation, iv. 347. Paddles from New Ireland, vii. 516. Paget, J., Chronometry of Life, iii. 117. Painting affected by Faults of Vision, VI. 450. Palgrave, F. T., Good Taste in Art, v. 376. W. G., Arabia, iv. 348. Palladium absorbs Hydrogen, vi. 50; its Alloy with Hydrogenium, 54. Palmer, Capt., on Sinaitic Inscriptions, VI. 91. John, improves Postal System, III. 459. Papuans, viii. 642. Paraflin, i. 6, 7 ; 135; Oil, &c. iv. 19, 20. Paraffins and their Alcohols, viii. 86. Parallaxes of Stars, xi. 96. Parallel Roads of Glen Roy, viii. 233. Roads of Lochaber, iii. 341. Parchment Paper, ii. 409. Paris, Comte de, Letter from, rt-spect- ing the Prince Consort, in. 430a. Donation, iv. 156. Parnell, J., Donation, iv. 516. Pasteur on Dust, vi. 2 ; on Spontaneous Generation, 10 ; on Science, ix. 23 ; Researches, xi. 161 ; xii^ 571. Paterno Volcanic Eruption, iv. 629, 640. Pauer, E., Works of Composers for the Pianoforte, xi. 171. Peat and its Products, i. 4. Peaucellier's Discovery of the Mechani- cal Conversion of Motion, vii. 179. Pectous State of Bodies, in. 425. Pendulum Experiments, i. 70 ; at Har- ton Colliery, ii. 17. Pengelly, W., Ossiferous Caverns of Devonshire, iii. 149. Vol. XI[. (No. 83.) Pengelly, W., Devonian Fossils and the Burdett-Coutts Geological Scholar- ships, &c. III. 263. Kent's Cavern, Torquay, iv. 534. St. Michael's Mount, Cornwall, v. 128. Penny Post established, ni. 458, 461. Penrose, F., Relations of Science to Architecture, i. 124. Application of the Mechanical Conversion of Motion, vii. 182. Peptous State of Bodies, iii. 425. Pepys, J., Donations, i. 54, 455; Por- trait presented, v. 24. Percy, J., Modes of extracting Gold from its Ores, i. 205. Smelting of Iron and Manufacture of Steel (no Ahstract), iv. 244. Perkin, W. H., Colouring Matters, v. 566. Discovery of Mauve Colour, in. 478; IV. 438. Permian Epoch, Climate of, n. 417. Perpetual Motion, ii. 152. Perry, J., on Japanese Mirrors, ix. 29, Rev. S. J., Transit of Venus, viii. 79. Solar Surface during the last ten ^ years, xii. 498. Personal Identification and Descrip- tion, XII. 346. Petitjean's Silvering Process, ii. 308. Petroleum, Manufactures from, ii. 506 ; relation to Mud Volcanoes, iv. 63^. Spirit, &c., imponed, vii. 402 ; Explosions, vii. 403 ; xi. 222 ; Storage and Conveyance, vii. 406 ; employed as an Illuminant, xi. 234. Pettigrew, J. B., Flight in relation to Aeronautics, v. 94. Phillips, J., Geological Sketches round Ingleborough, i. 278. Malvern Hills, ii. 385. Philosophy before Socrates, vi. 302. Phlogiston Theory revived, vi. 315. Phonograph, viii. 507; presented, ix. 37. Phosphorescence, in. 159 ; ix. 143, 431 ; x. 208. and Ozone, xii. 557. Phosphoric Acid, vi. 20. Phosphoroscope. in. 161. Phosphorus, Allotropic IModifications of, I. 135, 203. Photogalvanography, n. 343. Photographic Eclipse Results, in. 362 ; VI. 485. Spectra of Stars, ix. 285. Transparency of Bodies, iv. 43. Processes, vii. 220. 604 INDEX Photography, applied to Astronomy, xi. 104, 307 ; XII. 158. Instantaneous, x. 46. Photophone, ix. 532. PJivsical and Moral Science Analogies, vn. 12. Pliysiolo!?ical Action of Light, vn. 360 ; viii. 137 ; of Vanadium, vni. 224. Pianoforte Music, xi. 171. Pickersgill, H. W., presents Portrait of Kev. J. Barlow, in. 1. Picric Acid and Powder, vi. 520. Pictet, R., Experiments on Liquefac- tion of Gases, viii. 662. Pierotti's Discoveries at Jerusalem, iv. 23. Pigeons, various Breeds of, in. 197. Pineal Eye in Lizards, xii. 22. Pliints, Electric Currents in, i. 75 ; Growth of, in Cases, 407 ; their For- mations, III. 223 ; Distribution, vin. 568 : Excitability, X. 151 ; Movement, IX. 597. Plateau's Eesearches on Films, xi. 243. Platinimi, in. 321 ; Deville's Process fur obtaining it, 322. Wire, Ra.liation, ix. 20, 21. Plavfair, Lyon, Chemical Discoveries from the Exhibition of 1851, i. 131. Food of INlan, i. 313; in relation to his Useful Work, iv. 431, 662, 678. Chemistry of Agriculture, n. 289. Ploughs and Ploughing, i. 265. Poey's Researclies on Meteors, in. 144. Pogson, N., on Solar Eclipse, vi. 294. Poiseuille on Liquids under Pressure, VI. 26. Poisons, effects on Medusse. viii. 175. and Puisoiiing, xn. 220. Polarity (in Natural History and Geo- logy). I. 428 Polarization of Light, connection of Chemical Forces with, i. 45. Polarised Light, vin. 561, 582 ; x. 205 ; xii. 474; Spectra of, VII. 134; Colours of, 291. Pole, Wm., Donation, iv. 156. Pole, Prof.,-Culour Blindness, vi. 269. Political Character and Geographical Circumstances, vin. 529. Pollock, Sir Frederick, Decease of, 403 ; Resolution, xn. 410. F., Spinoza, vin. 363. History of the Sword, x. 377. Henry, elected Treasurer, xi. 467 ; Decease of; Resolution, xn. 525; Letter from Mrs. H. Pollock, xii. 563 ; his Portrait presented, 565. W. H., Romanticism, vin. 655. Pollock, VV. H., Dumas Pere, ix. 383. Shakspeare Criticism, ix. 577. Sir Francis Drake, x. 233. Garrick as an Actor, xi. 304. Polynesians, vni. 628, 644 ; Skull. 635. Poole, R. S., Greek Coins and Greek Art, IV. 306. Museum and Libraries of Alex- andria, X. 12. Discovery of the Biblical Cities of Eorypt. XI. 384. Popular Tales, vn. 378. Beliefs, xn. 134. Portraiture, P]nglish, Historical, its Fallacies. &c. iv. 543; Real and Ideal, VII. 430. Post-office, History of, in. 457. Pottery, English, xn. 212. Pouillet's Chronoscope. iv. 577. Poulton, E. B., Gilded Chrysalides, XII. 33. Powell, Baden, Foucault's Pendulum Experiment, i. 70. Analogies of Light and Heat, i. 172. Rotatory Motion, i. 393 ; Stability, II. 480. Power Meters, x. 241. Poynter, E. J., Old ami New Art,vi. 534. Preece, W. H., Electricity applied to Protection of Life on Railways, viii. 35. The Telephone, vin. 501. Multiple Telegraphy, ix. 194. Telegraphic Acliievements of Wheatstone, ix. 297. Safety Lamps in Collitries, xn. 204. presents Phonograph, ix. 37. Pre-!Miocene Aljxs, vn. 455. Prentice's Manufacture of Gun-cotton, IV. 622. Presents, Lists of, under General Monthly Meetings, throughout the volumes. Prestwich, J., Flint Implements of Abbeville, iv. 213. Pre-Socratic Philosophy, vi. 302. Pretsch, P., Process of Photogulvano- graphy, n. 348. Prieatley, J., on Vanadium, vni. 224 ; on Ammonia, ix. 51. Primeval Earth, Chemistry of, v. 178. Vegetation, vi. 165. Primogeniture, ix. 561. Printing with Artificial Indigo, ix. 590. Pritchard, C, Telescope, iv. 641. Proctor, R. A., Star-groupiug-drift, &e. VI. 143. TO VOLS. I. TO XII. 605 Projectiles, ix. 232, 319. Protyle, xii. 50, Psilophvtou princeps, vt. 167. Public School Education, v. 26, 273. Puddled Steel, viii. 321. Puller, A. Giles, Donations, iv. 290; V. 1, 309; VI. 100,422. Putrefaction and Infection ; their rela- tion to Optics, VIII. 6; to Physics, VIII. 467. Pygmy Kaces of Men, xii. 266. Pyrometers, vi. 440. PVthagoras, vi. 303 ; his Philosophv, '311. QuADRiviUM, VIII. 453, 464. Quartz, viii. 561 ; Crystal>\ xii. 489 ; Fibres, xii. 547. ] Queen, Address on her Jubilee, xii. ' 173 ; reply, 178. Quiuoidine in Animals, iv. 564. Kace, Professor Flower on, viii. 649. Radiant Heat and Light, their Identity, VI. 417. Matter, ix. 142. Heat converted into Sound, x. 175. Radiation and Absorption, with refer- ence to Colour of Bodies, iv. 487. through Air, iv. 4, 233. Experiment, ix. 264. Thoughts on, x. 253. Radiometer, viii. 56 ; ix. 140. Rae, J., Arctic and Sub-Arctic Life, viii. 378. Railway : Protection of Life by Elec- tricity, VIII. 35. Locomotion, x. 136. i Rainbows, x. 455 ; White, 462 ; Arti- I ficial, 464. Raindrops, Impressions of, i. 50. Ralston, W. R. S., Russian Folk-lore, VI. 32b. Popular Tales, vii. 378. Ramniohun Roy, x. 470. Ramsay, A. C, Climate of the Permian Epoch, II. 417. Geology of Canada, &c. ii. 522. — — Eozoon and the Laurentian Rocks of Canada, iv. 374. Old Continents, vii. 32. Rhine, vii. 279. Pre-Miocene Alps, vii. 455. Geology of Gibraltar, &c. viii. 594. • Obser%'ations on Niagara, vii. 88. Runkine, W. J. M., Sea Waves, vi.355. Rapieff, M., presents Electric Lamps, IX. o7. Electric Light, ix. 16. Rare Earths, xii. 39. Rarefied Air, Combustion in, iii. 331. Rate, L. M., Donations, x. 266 ; xi. 469 ; xii. 372. Rawlinson, SirH. C, Cuneiform Inscrip- tions at Babylon and Nineveh, i. 84 ; III. 5:-^6. Excavations in Assyria and Baby- lon. II. 143. Results of Cuneiform Discoverv, IV. 335. ■ Livingstone's Explorations (no Ahdract), vii. 54. Geography of the Oxus (no Ahs- tract), IX. 137. Rayet, on Solar Eclipse, vi. 293. Rayleigh, Lord, Dissipation of Energy, VII. 386. Acoustical Phenomena, viii. 536. Water Jets and Water Drops (no Abstract), xi. 284. Colours of Thin Plates, xn. 81. Diffraction of Sound, xii. 187. Iridescent Crystals, xii. 447. • Elected Professor of Natural Philosophy, xii. 136. &c. Real and Ideal Portraiture, vn. 430. Re'aumur's Observations on Metals, XI. 395. Reay, Lord, Social Democracy in Ger- many, IX. 412. Redwood Tree, vin. 578. Reed, E. J,, Iron-clad Ships, vi. 95. Ships and Guns, vi. 211. Reed and String Instruments, vii. 488. Reiiex Action from the Cerebral Cortex, XI. 29. Refraction of Light, viii. 351; x. 196, 204. Refractive Indices, Table of, x. 203. Regenerative Furnaces, xi. 471. Regent's Canal Explosion, vii. 408. Regnauld, J., Experiments on Fluor- escence in Animals, iv. 571. Reich and Richter discover Indium, vi. 393. Renan, E., Marc-Aurele, ix. 369. Renard, Alphonse, La Reproduction artificielle des roches volcaniques, xii. 330. Resistance of Ships, viii. 188. Respirators for Smoke, vi. 378. Reynolds, J. E., Alcohols from Flint and Quartz, vii. 107. Osborne, Vortex Motion, viii. 272. Two Manners of Motion of Water, XI. 44. 606 INDEX Reynolds, Osborne, Experiments show- ing Dilatancy, xi. 354. Rhine, Physical History of, vii. 279. Rhizopod Type of Animal Life, ii. 497. Richardson's Lifeboat, i. 22L Riddell, on Socrates' Dsemon, yi. 411. Riepe's Steel, Tin. 321. Riess's Electrical Researches, ii. 133. Rig- Veda described, iv. 137. Rijke's Experiments on the Magnetic Force and Electric Discharge, iii. 171 ; on Production of Sound by Heat, VIII. 541. Ritchie, W., Torsion Balance, viii. 62. River Pollution, vii. 370. Action, X. 268. Roberts, Dr., on Biogenesis, viii. 20. Roberts-Austen, W. C, Properties Common to Fluids and Solid Metals, XI. 395. Curious Properties of Metals and Alloys, XII. 367. presents Portable Assay Furnace, " XII. 365. Robius' Experiments with Fired Gun- powder, VI. 273. Robinson, G. A., Tried to Save Tas- manians, viii. 623. Rodman, Major, Experiments on Gun- powder, VI. 275. Rcemer's Determination of Velocity of Light, VII. 472. Rogers, H. D., Geology of North America, ii. 167. Parallel Roads of Glen Roy, in. 341. Rolleston, G., Brain of Man and certain Animals, in. 407. Influence of Anglo-Saxon Con- quest, VI. 116. Early Inhabitants of N. England, VII. 300. Rolling Contact of Bodies, xii. 130. Romanes, G. J., Nervous System of Medusse, viii. 166. Evolution of Nerves and Nervo- Systems, viii. 427. Mental Evolution {no Abstract), IX. 386. Starfishes (no Abstract), x. 184. Darwinian Theory of Instinct, xi. 131. Mental Differences between Men and Women, xii. 78. Elected FuUerian Professor of Physiology, xii. 201. Roman Catacombs, &c. vii. 316. Ornament, ix. 444. Antiquities in London, x. 29. Romanticism, viii. 655. Rorquals, x. 363, 368, 370. Roscoe, Sir H. E., Chemical Action of Light, II. 223. Measurement of the Chemical Action of the Solar Rays, in. 210. Bunsen and Kirchhoft''s Spectrum Observations, in. 323. Direct Measurement of the Sun's Chemical Action, iv. 128. Meral Indium, and Discoveries in Spectrum Analysis, iv. 284, 0|)alescence of the Atmosphere, IV. 651. Vanadium, v. 287; viii. 221. Alizarine, v?. 120. M. C. Vincent's Chemical Indus- trv, IX. 51. Indigo and its Artificial! Produc- tion. IX. 580. Recent Progress in the Coal Tar Industry, xi. 450. Aluminium, xii. 451. Rosse, Lord, Heat of the Moon, vn. 139, Rotation of Earth shown by the Pendu- lum, I. 70. Rotatory Motion, i. 393; Stability, n. 480. Roupell, R. P., Donation, iv. 177. Rousseau's Influence on Society, vi. 475 ; ' Emile,' viii. 459. Roxburgh, W., Cartesian Barometer, i. 426. Royal Academy of Music, vi. 436. Institution Chemical Researches, IV. 309, 465 ; Laboratories, vn. 1. Institution, Original Proposals for, VI. (ix.) ; Originator, x. 407. Rubidium, in. 326 ; vi. 391 ; Spectrum, IX, 207. Rucker, A. W., Liquid Films, xi. 243. Electrical Stress, xn. 406. Ruhmkorft^'s Induction Apparatus, in. 139 ; Coil, IX. 5. Rumford's Proposals for Establishing a Public (afterwards the Royal) Institution vi. (ix.) vn. 1. Scientific Discoveries, vi. 227. on Fired Gunpowder, vi. 274 ; Heat, X. 254; xi. 338; Fireplace Construction, xi. 344. Life, x. 407 ; Work, 444^ Ruminant Quadrupeds, in. 256. Rumker, on SolarjEclipse (1860 ), vi. 286. Ruskin, J., Tree Twigs, in. 358. Forms of the Stratified Alps of Savoy, IV. 142. State of Modern Art (no Abstract), V. 187. TO VOLS. I. TO XII. 607 EiTskin, J., Architecture of the Somme {no Abstract), v. 450. Verona and its Rivers, vi. 55. Eemaiks on Michael Augelo, ti. 537 ; and on Philosophy of Art, 539. Enssell, John Scott, Wave-line Ships and Yachts, i. 115. English Ships and American Clippers, i. 210. Iron Walls of England, iii. 503. Nature and Uses of Gun-Cotton, IV. 292. Crystal Palace Fire, v. 18. Lord Arthur, Presents Ersch and Gruber's Encyclopedia, viii, 559. Russian Folk Lore and Songs, vi. 326. Secret Societies, viii. 405. Domestic Industry, x. 359. Rutherford, W., elected Fullerian Pro- fessor of Physiology, vi. 544 ; re- signed, VII. 3o9. Sabine, E., observations on Atmo- spheric Magnetism, i. 238. Saccharine, xi. 462. Safety Lamps, Experiments, vii. 400 ; in Collieries, xii. 204. St. Peter's, at Rome, aided by Science, IV. 12. Sal Ammoniac, ix. 51. Salamon, A. Gordon, Yeast, xii. 571. Salic Law, ix. 541. Salmon, W., Botanicnl Works presented by. III. 193 ; Donations, iv. 290 ; vii. 164. Salts and Acids, iii. 234. Samoans, viii. 646. Sand Blast and Sand Emsion, vii. 84. Sanderson, J. Burden, Dionsea Mus- cipula, VII. 332. Excitability of Plants and Ani- mals, X. 146, 151. Cholera: its Cause and Preven- tion, XL 288. Some Electrical Fishes, xii. 139. Sandwith, H., Siege of Kars, ii. 246. Santonine produces Colour Blindness, VI. 271. Sap, Rise of, i. 197. Savage, Miss A., presents her Father's Works on Printing in Colours, ii. 333. Savage Thought in Civilisation, v. 522. Savart's Researches, i. 447. Savory, W. S., Relation of the Animal and Vegetable to the Inorganic Kingdom, iii. 368. Savory, W. S., Motion in Plants and Animals, iii. 433. Dreaming and Somnambulism, IV. 207. Scarlet Fever, Etiology of, xii. 150. Scattering of Light, vi. 189, Schafer, E. A., elected Fullerian Pro- fessor of Physiology, viii. 665. Scharf, G., Portraiture : its Fallacies and Curiosities as connected with English History, iv. 543. Scheele discovers Chlorine, vi. 199. Schehallien Experiment, ii. 18. Scheibler's Tonmesser, ix. 538. Schelske, Nervous Agent, iv. 587, 590. Schiapparelli on Orbit of Meteors, ix. 45. Schliemann's Excavations at Troy, vii. 119; Letter from, 122. Schmidt's Drawing of Solar Eclipse (1851), VI. 293. Schonbein's Ozone, i. 94 ; vi. 546 ; and Antozone, iii. 70. Experiments on Variations of the Colour of Bodies, i. 400. Schrotter's Amorphous Phosphorus, i. 135. Schultze's Gun-sawdust, iv. 621. St'hunck on Indigo, ix. 582. Schuster, A., Modern Spectroscopy, ix. 493. Schwabe's Observations of Spots on the Sun, i. 237. Schwann, Discovers Yeast Plant, vi. 7 ; Researches, viii. 29. Schweinfurth on Bongo Women, ix. 395. Science as a Branch of Education, ii. 556 ; applied to Calico Printing, iii. 201 ; to Military Purposes, 243. Scientific Men, their Nature and Nur- ture, VII. 227. Theories, viii. 216. Sclater, P. L., Zoological Distribution, viii. 511. Scott, A. J., Physics and Metaphysics (no ^&.sf racO, II. 439. R. H., Work of the Meteorological Office, V. 535. Weather Knowledge, vii. 34 ; x. 323. ■ S., Donation, v. 24 ; viii. 42. Scottish Highland Language, &c. ix. 547. Sculpture, x. 280 ; Mode of Exhibiting, VII. 431. Sea, Temperature, &c. vi. 63, 81, 82. Waves, VI. 355 ; vii. 297. GOS INDEX Sedgwick, J. Bell, Donation, xii. 370. Mrs. Bell, Donation, xii. 370. Seedlings, XT. 517. Seeds, ix. 595 ; Dispersion, 598. Seismographs, xii. 362. Seismometers, xii. 361. Selenium, yiii. 69 ; ix. 524 ; Action of Light on, Tin. 70 ; Ci-11, ix. 525. Sensation, vi. 341 ; ix. 115. Sensitive Plants, ix. 597 ; x. 152. Sequoias, viii. 578-580. Serapis, Temple of, Changes in, ii. 207. Serpent Worship, v. 453. Serrin's Electric Lamp, ix. 7. Servetus, M., on the Heart, viii. 402. Setschenow, I., Experiments on Fluor- escence in Animals, iv. 571. Sewage Contamination of Water, v. 360-3. Shade Temperature, x. 17. Shakespeare, iv. 470 ; Criticism, ix. 577; his Opponents, vii. 218. Shaw, H. S. Hele, Rolling Contact of Bodies, xii. 130. Captain, Smoke Jackets, vi. 372. Shepherd's Electro-magnetic Clocks, I. 109. Sherwoodole, ii. 507. Shippard, W. H., Central America and the Ship-Canal, i. 75. Ships, English and American, i. 115, 210. and Guns, vi. 211. Resistance, viii. 188. Shooting Stars, iii. 143; iv. 87, 644; V. 164. Shot-drill Experiments, iv. 679. Sidereal Astronomy Problems, xi. 91. Sidney, E., Rise of the Sap in tlie >prin< 19: Siege Operations, ii. 42. Siemens, Sir C. W., Regenerative Steam-engine, ii. 227. Measuring Temperatures by Electricity, vi. 438. " Faraday" Steamship, vii. 310. Action of Light on Selenium, viii. 68. Dvnamo Electric Current, ix. 334. Solar Physics, x. 315. his Gas Furnaces, &c. tii. 536; process of Steel manufacture, viii. H25 ; Magnetic Discoveries, ix. 10. presents Dynamo - Machine, Boiler, &c. viii. 559 ; ix. 37. ■ Decease of; Resolution, x. 405. Lady, Presents Selenium Eve, x. 474 Siemens, Fredk., Dissociation Tem- peratures, XI. 471. Werner, on Action of Li>j:ht on Selenium, viii. 70 ; Magnetic Dis- coveries, IX. 8, 10 ; Letter from, x. 473. Sight, Defective, ti. 454. Silica, its Use in the Arts, i. 422. Silver Fulminate, ix. 64, G6. Sinai, Ordnance Survey of, vi. 83 ; Inscriptions, vi. 91. Sitaris Beetle, Metamorphoses of. iv. 553. Skulls, Deformed, ix. 401. Slave Trade, vii. 239. Sleep, VI. 424 ; of Plants, ix. 598 ; x. 154. Smeaton's Lighthouse, xii. 425. Smell. IX. 118. Smith, A., Deviation of the Compass in Iron Ships, iv. 518. B. Leigh, Donation, v. 1. E., Researches on Animal Work, III. 355 ; IV. 676. Goldwin, Geographical Circum- stances and Political Character, viii. 529. Robt. Angus, Organic Matter in the Atmosphere, iii. 89. on the Air of Manchester, vi. 12. Willoughby, on Action of Light on Selenium, viii. 70. Volta-Electric and Magneto- Electric Induction, xi. 119. R. Boswortli, Early Life of Lord Lawrence in India, x. 183. W. Robertson. Mohammedan Mah- dis, XI. 147. Smoke Jacket for Firemen, vi. 371. Rings, VIII. 274; ix. 521. Smvth, Piazzi, Ascent of Peak of Teneritfe, ii. 493. his Rotatory Apparatus ex- plained, II. 485. W. W., Coal, III. 510. Soap Bubble, x. 191. Soap destroyed by various Waters, v. 358. Sobrero discovers Nitro-glycerine, vi. 620. Social Democracy in Germany, ix. 412. Society in the 4th Century a.d., xii. 75. Socrates, Daemon of, vi. 402. Sodium presented, iv. 153. Manufacture of, xii. 453, Spectrum, x. 257. Soils of England, Properties of, iv. 110. Solar Corona, xi. 202. TO VOLS. I. TO XII. 609 Solar Energy, xi. 279. • Physics, V. 580 ; x. 315, • Rays, Chemical Action of, iii. 210, 387; iv. 128. Spectrum, x. 60, 248. Spots, Observations of, i. 237 ; XII. 498.' Surface, xii. 498. Solly, R, H., Legacy from, ii. 526. S. R., Donations, iv. 109, 243, 372, 549. Somerville, Mrs., Bust of, presented, VII. 30. Somnambulism, iv. 210. Sondhauss's Acoustic Experiments, VIII. 538. Sonstadt, E., presents Magnesium, iv. 151. Sopwith, T., Mining Districts of the North of England, ii. 57. Sorby, H., Cleavage, ii. 308. Soret investigates Ozone, vi. 548. Sorting Demon of Maxwell, is. 113. Sotheby, S. L., presents 'Principia Typographica,' iii. 167. . Sound, X. 175 ; Velocity of, vii. 344 ; Conduction of, viii. 501 ; certain Phenomena, viii. 536 ; Diffraction of, XII. 187. South, Sir James, bequeaths Faraday's MS. Notes, Magnetic Ring, &c. vi. 185. Space, IX. 519. Spanish Armada, xii. 307. Spark Discharge, Spectrum, ix. 680. Spartan Constitution, &c. iv, 263. Species and Races, their Origin, iii. 125. Spectra, ix. 496 ; of Stars, 285 ; of the Elements, iv. 46 ; of Comets, x. 3 ; of Meteorites, 7 ; Ultra-Violet Spec- tra of the Elements, 245, 258 ; Origin and Identity of, ix. 674. Spectroscope presented, vi. 379. Spectroscopic Investigation, ix. 204, 285, 674; xii. 83. Spectroscopy, Modern, ix. 493. Spectrum Analysis, in. 323 ; vi. 390 ; Discoveries in. iv. 284 ; applied to the Heavenly Bodies, v. 475, 580. Speke, Captain, Source of the Nile (no Abstract), iv. 150. Spencer, H., Theory on Genesis of Nerves, viii. 429. W. B., Pineal Eve in Lizards, xii. 22. Spencer's Photographic Processes, vii. 222. Spenser, on Ireland, ix. 574. Spheroidal State of Liquids, i. 179. Sphygmograpb, vii. 214. Spigelius on the Heart, viii. 494. Spinoza, Life, Works, &c. viii. 364. Spontaneous Explosions, vii. 413. Generation, vi. 10, 368 ; viii. 8, 399. Sporadic Meteors, ix. 41. Spottiswoode, W., Successive Polarisa- tion of Light, VI. 205. Crystals Submitted to Circularly Polarised Light, vi. 506. Laboratories of Royal Institution, VII. 1. Spectra of Polarised Light, vii. 134. Combinations of Colour by Polar- ised Light, VII. 291. Experiments with a great Induc- tion Coil, VIII. 359. Quartz, viii. 561. Nocturne in Black and Yellow, VIII. 582. ■ Electricity in Transitu, ix. 427. IMatter and Magneto-Electric Action, X. 75. elected Treasurer, iv. 434 ; Secre- tary, VII. 105 ; resigns, viii. 668 ; Resolution on Decease of, x. 399. Spring, W., Researches on Metals, xi. 405; XII. 368. Stahl publishes the Phlogistic Theory, VI. 317. Stanhope, Earl, Influence of Arabic Philosophy in Mediseval Europe, iv. 506. Stanley, Dean, Westminster Abbey, IV. 598. Roman Catacombs, &c. vii. 316. Star-grouping, &c. vi. 143. Stars, Spectra of, ix. 285. Proper Motions of, x. 115. with Parallax, ix. 518. Statham, H. H., Architectural Design, IX. 89. Ornament, ix. 440. Intellectual Basis of Music (no Abstract), x. 144. Statham's Arrangement of Electric Telegraph Wire for Experimental Purp'oses, i. 346 ; his Fuze, 347, 355. Statues, X. 280. Steam-engine, Regenerative, ii. 227. Steel, Manufacture of, viii. 319; xii. 103 ; Future of, viii. 331. Stellar Systems, History of, xii. 379. Stenhouse, J., Applications of Charcoal to Sanitary Purposes, ii. 53 ; Re- spirators, VI. 373. 610 INDEX StepheD, Leslie, S. T. Coleridge, xii. 233. Stethophone, iii. 63. Stevenson, W., Auroraa Boreales, i. 274. Stevens's Battery, iii. 508. Stewart, Balfour, Forces concerned in producing Magnetic Disturbances, IV. 55. Discoveries concerning the Sun's Surface, iv. 378. Existence of a Material Medium " pervading Space, iv. 558. The Sun as a Variable Star, v. 138 Sticks, Clubs, &c. vii. 513. Stipa pennata Seed, ex. 624. Stokes, G. G., Refrangibility of Light, I. 259 ; X. 205. Discrimination of Organic Bodies by their Optical Properties, iv. 223. Researches on Fluorescence, iii. 160 ; IV. 564 ; x. 208 ; Screen, x. 245, 258. obtains Actonian Prize, xi. 376. Stone Age, iv. 31. Stone, W. H., Musical Pitch, ix. 536. Stoney, G. J., November Meteors, ix. 40. How Thought presents itself in Nature, xi. 178. Stonyhurst, Observations at, xii. 498. Stooks, Miss E. M., Donation, iv. 177. Stoims, described, vii. 41. Storm Warnings, v. 539 ; x. 329. Stowmarket Explosions, vi. 529. Strachey, Lieut.-Gen., Indian Famines, Tin. 407. Stradiuarius, ix. 307. Stream-Line Theory, viii. 191. Stress, Etfect on Magnetisation, viii. 591 : Electrical, xil" 406. Striae in Vacuum Tubes, viii. 360 ; ix. 431 ; X. 83. String Instruments, vii. 488. Struve on 61 Cygni, ix. 514, 516. Sturm, John, on Education, viii, 455. Stylidiura, x. 157. Submarine Cables, v. 574. Subway to France, vi. 110; x. 121. Suggestion, its Influence on Movement, I. 147. Sulphur, its Allotropic Modifications, I. 202 ; and Melting Points, 449. in Coal Gas, vi. 489. Sun, Physical Character of, in. 327, 387 ; Total Eclipse of, 362 ; Theory of the Origin of its Heat, 533 ; xii. 1 ; Chemit^al Action of, its Measurement, IV. 128, 654 ; Discoveries respecting its Surface, iv. 378, xii. 498 ; its Colour, XI. 265; xii. 69; Spots, xii. 498. Sun's Heat, xii. 1. Sunlight ; its Energy, viii. 66. Temperature, x. 18, 22, 24. and the Earth's Atmosphere, xi. 265. Colours, xii. 61. Superstitions, v. 87, 523. Surface Tension, x. 450 ; xi. 243. Swan, J. W., Electric Lighting by In- candescence, X. 33. Swanwick, Miss Anna, Donation, iv. 23L Sword, X. 377. Sylvester, J. J., Mechanical Conversion of Motion, VII. 179. Sympathetic Inks, vii. 458. ■■ Nervous System, xi. 530. Synthesis of Organic Bodies, iv. 199. Synthetically-formed Substances by the Plant or by the Chemist, iv. 568. Syren's Action in Fogs, vii. 173. Tait, p. G., on Ozone, vi. 549 ; Smoke Rings, VIII. 274; Comets, x. 10. Talbot, H. Fox, Photographic Engrav- ing, II. 347. Talmud, v. 3SG. Tasmania, viii. 620 ; Natives, 621. Taste, IX. 120. Taylor, Sedley, Galileo's Tri^l, vii. 304. W., Educating tlie Blind, i. 290. Teale, T. Pridgin, Principles of Domes- tic Fireplace Construction, xi. 338. Technical Education, xii. 113. Teeth, Structure and Homologies of, i, 365. Telegraph, Submarine, ii. 394. Telegraphy, ix. 194, 297. Telephone, viii. 501. Telephotography, ix. 533. Telescope, iv. 641 ; Objectives and Mirrors, xi. 413. Temperature of the Sea, vi. 64, 81, 82. Temperatures, xi. 148, 471, 550 ; measured by Electricity, vi. 438. and Radiation, x. 315 ; Ratio, 317 ; Observations, 261. Temple of Jerusalem, iv. 366. Tenant Farmers, ix. o6d. Tennant, invents Bleaching Powder, VI. 201. TO VOLS. I. TO XII. 611 Thalf's' Philosophy, vi. 305. Thalline, xi. 401." Tliallium, iv. 62 ; vi. 302. Thermometers, vi. 440. Theimopile, x. 255. Tliompson, B. (Count Rumford), x. 407. S.lvauns P., Optical Torque, xii. 474. Thomson, Sir W., Motive power, ii. 199. Atmospheric Electricity, iii. 277. Tides, VII. 447. Effects of Stress on Magnetisa- tion of Iron, &c. VIII. 591. Sorting Demon of Maxwell, ix. 113. Elasticity, as possibly a Mode of Motion, IX. 520. Size of Atoms, x. 185. Capillary Attraction, xi. 483. The Sun's Heat, xii. 1. Electrostatic Measurement, xii. 561. I seiits Electric-current Measur- ing Instruments, xii. 370. Joseph, Exploration of Masai Land, XII. 199. J. Millar, Suspended Crystallisa- tion, XI. 508. Thorpe, T.E., Chemical work of AVohler, X. 477. Thought in Nature, xi. 178. " Thunderer " Gun Explosion, ix. 221 ; Sequel, 309. Tides and Tide Gauge, yii. 447. Tidy, C. Meyiiiott, Poisons and Poison- ing, XII. 220. Tilghman's Sand Blast, vii. 84. 85. Time, Geological, i. 287, 428 ; viii. 129 ; IX. 268. required for Transmission by the Nerves, iv. 575. " Time of the Masters" (Italian Art), VI. 59. Time-reckoning, xi. 387. Tonite, Experiments with, ix. 80 Topinard, on Australians, viii. 607 ; Tasmanians, 626. Torpedo Explosion, vii. 390. Town Climate, x. 24. Transit of Venus, viii. 79. Transpiration, vi. 26. Treadwheel Work, iv. 676. Tree Twigs, in. 358. Tree Worship, v. 453. Tribe, A., Experiments with Dr. Glad- stone, viii. 183. Tricycles, xi. 13. Trilobites, Theory respecting, iii. 268. Vol. xii. (No 83.) Trivium, viii. 453, 464. Troy, VII. 119. Tudor, E. Owen, Donation, iv. 572. Tuke, T. H., Donation, iv. 156. Tumuli, York.shire Wold, v. 78. Tunnels, vi. 110; x. 123; Tunnelling. 488. Turbid Media, ix. 345. Turner, C. E., Domestic Industry in Russia, x. 359. Turner's Pictures affected by Fault of Vision, VI. 450. Twining, INIiss Eliz., presents her Works on Plants, iii. 107. Tylor, Alfred. Roman Antiquities found in London, x. L'9. E. B., Early jMental Condition of Man, V. 83. Savage Thought in Modern Civili- sation, V. 522. Ordeals and Oaths, viii. 152. History of Games, ix. 125. on Theory of the Alphabet, vi. 471. Tyndall, John, Influence of Material Aggregation upon the Manifestations of Force, i. 254. Eruptive Phenomena of Iceland, i. ^329. Vibration and Tones produced by the Contact of Bodies having different Temperatures, i. 356, Motion of Liquids, i. 446. Magnetic and Diamagnetic Force, II. 13, 159. Leyden Battery, ii. 132. Cleavage ol Rocks, &c. ii. 295. Glaciers, ii. 320. Lissajous' Acoustic Experiments, II. 441. Physical Properties of Ice, ii. 454. Mer-de-Glace, ii. 544. Veined Structure of Glaciers, in. 72. Transmission of Heat through Gases, in. 155. Influence of the Magnetic Force on the Electric Discharge, in. 169. Alpine Phenomena, in. 269. Action of Gases and Vapours on Radiant Heat, in. 295. Physical Basis of Solar Chemistry, III. 387. Absorption and Radiation of Heat by Gaseous Matter, in. 404. Force, in. 527. Radiation through the Earth's Atmosphere, iv. 4. 2 T 0L2 INDEX Tyndall, Jolm, Kesearchcs on Radiant Heat, IV. 14ri. Contributions to Molecular Phy- sics, IV. 233. A Magnetic Experiment, iv. 3! 7, Combustion bv Invisible Rays, IV. 329. Radiation and Absorption, with reference to the Colour of Bodies, and their State of Aggregation, iv. 487. Experiments on the Vibrations of Strings, iv. 685. Sounding and Sensitive Flames, V. 6. Experiments of Faraday, Biot and Savart, v. 188. " Faraday as a Discoverer," v. 199-272. Chemical Rays and the Light of the Sky, v. 429. Dust and Disease, vi. 1. Colour of Water ; and the Scatter- ing of Light, VI. 189. Dust and Smoke, vi. 3(Jo. Identitv of Light and Radiant HcHt, VI. 417. Niagara, vii. 73. Acoustic Transparency, and Opacity of the Atmosphere, vii. 1G9. Acoustic Reversibility, vii. 344. Wliit worth's Planes, &c. vii. 524 ; Standard Measures, 520 -, Guns, 527; Steel, 535. Optical Condition of the Atmo- sphere and Putrefaction and Infec- tion, VIII. G. Parallel Roads of Glen Roy, viii. 233. A Combat with an Infective At- mosphere, VIII. 467. Putrefactive and Infective Organ- isni'j, VIII. 467. Feg Signals, viii. 543. Electric Light, ix. 1 ; Lecture re- peated, 37. Goethe's ' Farbenlehre,' ix. 340. Conversion of Radiant Heat into Sound, x. 175. Action of JNIolecules on Radiant Heat (no Abstract), x. 13. Thoughts on Radiation, x. 253. Count Rumford, x. 407. Rainbows, x. 455. Living Contagia, xi. 161. Tliomas Young, xi. 553. Researches in the Royal Institu- tion, vn. 7, 11 ; Experiments on Ozone, VI. 550 ; Presents Apparatus, vii. 55. Tyndall, John, Present to, on his marriage, viii. 178. Donations, iv. 153, 156 ; vi. 422 ; x. 214. Elected Professor of Natural Phi- losophy, I. 339, &c. ; Letter of Resig- nation, XII. 94 : Resolution, 95 ; Elected Honorary Professor of Natural Philosophy, xii. 136, &c. Ungulata, Owen's List of, ii. 260 ; Classification of, vii. 98. Uintatherium described (^with cut), viii. 115, 116. Unconscious Activity of the Brain, v. 338. Universal Time, xi. 387. Uranium Glass, x. 209. Uric Acid, x. 478, 480. Vacua, Peculiar, how prepared, iii. 9 ; Electric Discharge in, 6, 7; ix. 138, 432 ; X. 83. Vanadium, v. 287 ; viii. 221. Vapours, their action on Radiant Heat, III. 295, 406; iv. 5, 149, 488; pro- ducing Sound, X. 177. Varley, C. F., Atlantic Telegraph, v. 45. on Telephone, viii. 503 ; Dynamo- Electric Maehines. ix. 10, note. Vase Paintings, x. 285. Vaughan, H., Donations, iv. 347 ; v. 4. Vedas, the Sacred Books of the Hindus, IV. 135 ; X. 470. Vegetable, Animal, and Inorganic Kingdoms, their Relations, iii. 368 ; VIII. 28. Velocities of Electricity, Light, Sound, Nervous Agent, &c. iv. 588 ; Light, VII. 472 ; Sound, 344 ; Detonation, ix. 64, 78; Projectiles, 226, 319; Pro- jiagation, x. 198. Ventilation, ii. 236 ; by the Parlour Fire, I. 761. Venus, Transit of, viii. 79, So. Vernon, Lord, Present of Dante, v. 607. Verona and its Rivers, vi. 55. Verrier, on Oriiit of Meteois, ix. 46. Vertical Cireulation in Water, vi. 246 A ibrating Meter, x. 239. Vibrations of Strings, iv. GSo. Villari, Eifects of Stress on Magnetisa- tion, VIII. 592. Vincent, B., resigns offices of Assistant f^ecretary and Librarian, xii. 410. M. Camille, New Chemical In- dustry, IX. 51. " Vine " in the Catacombs, vii. 325. TO VOLS. I. TO XII. 613 Violins, Old, ix. 305. Vision, Faults of, vi. 450. Visions of Sane Persons, ix. 644, Vital and Physical Forces, their Rela- tions, III. 206. Vivian, E., Meteorology and a Balloon Ascent, n. 437. Voelcker, A., Properties of Soils, and the Productive Powers of the Soils of England, iv. 110. Volcano of Krakatoa, xi. S5. Volcanoes, Conical Form of, iii. 125. Volta-Electric Induction, xi. 119. Voltaic Batteries, ix. 1, 2, 3. Voluntary Movement, Physiology of, I. 37, 147. Von Lang's Researclies in Crystallo- graphy, III. 98. Vortex Motion, viii. 272. Vrolik, Apes, iii. ItJ. Wagner, A., and the Music of the Future, vii. 26 ; his eulogy of Weber, VII. 211. Waldstein, C., Influence of Athletic Games on Greek Art, x. 272. Wales, Prince of, elected Honorary ML-mher and Vice-Patron, iv. 3, 13 ; Present frum, 176; Address to the Queen on his Recovery, vi. 474 ; Reply, 511 ; returns thanks for Sir F. Abel's Discourse, xii. 126. Walker, C. V., Railwuy Telegraph Sig- nals, II. 403. A. De Noe, presents a Chinese Library, iii. 219. Wallace, A. R., on Malays, viii. 641. D. M., Secret Societies in Russia, viii. 405. Waller, A., Nerves, iii. 378. Wallich, G. C, Nature of the Deep-sea Bed, and the Presence of Animal j Life at Vast Depths in the Ocean, ' III. 299. I Wanklyn, J. A., Synthesis of Organic Bodies, IV. 199. Ward, S. H., Growth of Plants in closely glazed Cases, i. 407. Warington, Geo., obtains Actonian Prize, IV. 399. R., Aquarium, ii. 403. Warner, Messrs., Bell-fuunding, ii. 380. " Warrior ' descril)ed, iii. 508. Water Supplv of London, ii. 47, 466 ; for the Metropolis, v. 109, 346. Analyses, v. 113, 122, 35^. Colour of, VI. 190 ; Particles in, VI. 195. Water, Chemical Decomposition, viii. 179; Solid, viii. 302. Spectrum, ix. 699 ; x. 62, 64. Molecule of, iv. 118. Meters, x. 235. Motion of, XI. 44. Watson, Bp., on Plilogiston, vi. 319. Wave-line Ships and Yachts, i. 115, 210. Wave Length, Tables of Data, &c. x. 187, 198. Theory, xi. 562. Waves Illustrated, x. 188, 199, 209. Weal den Formation, Fauna and Flora of, I. 141. Weather Knowledge, vii. 34 ; x. 323. Weber and his Times, vii. 199. Weldon's Process of Manufacturing Chlorine, vi. 203. Weldon, W. F. R., Adaptation to Sur- roundings as a Factor in Animal Development (no Abstract), xi. 287. Wellington, Duke of, Cast of his Fea- tures after Death presented, iii. 274. " Wellingtonia," viii. 578. Weils, on Dew, x. 2.54. Westmacott, R., Art-Education, and how to view Works of Art, iv. 381. -t; — Art, VI. 102 ; Mausoleum of Hali- carnassus, 105; British Museum, 107. Westminster Bell, ii. 368. Abbey, iv. 598; xii. 217. — — Deau of, on Westminster Abbey, IV. 598 ; XII. 217; Roman Catacombs, &c. VII. 316. Abp. of, on the Daemon of Socrates. VI. 402. Westwood, J. O., Metamorphoses of Insects, III. 375. Whalebone, x. 366, 369. Whales, x. 360. Wheatstone, Sir C, Electric Telegraph, II. 394, 556. Experiments on Successive Polari- sation of Light, VI. 205. Determination of the Velocity of Light, VII, 474, Presents Magneto-Electric Clock. VII. .30 ; Donation, iv. 177. Decease of, viii. 1. his Magic Lyre, viii. 501. Magnetic Discoveries, ix. ] 0. Telegraphic Achievements, ix. 297. Wheels moving round a Curve, xi. 19. Whitney, on Sequoia, viii. 579. Whitney, Mount, xi. 275. Whitworth's Planes, vii. 525; Standard Measures, 526; Guns, &c. iii. 248; vii. 527 ; Steel, 535. rai INDKX TO vol. I. TO Xll. Wiia Flowers ftiul Insoots. vii. Sol. ^ViKi<.\ 11.. prosonts: Mrtsrnoto-Klootrio Maohino, v. 1 ; dosorihtHl. ix. 8. Wilkos. on Samoans. viu. (>i(>. Willirtius, G., Pbcovorios at .lorusalom. IV. 23. C. 0., Artitioial Fortuatioii of C^iiTniu' Substaiu'os. v. 878. Fonialo Poisoners {no Aht^tract^, N. 170. \V. M.. Ixnuifoivl's Seientitie Dis- iHtverioss vi. 'J*J7. NViHianisou. A. W., Flhevirteaii n, i. IH\ Gerhar«lt*s Discovery of the Anhy- dnnis Oriranie Acids, i. -oi). Classitication of the Elements in n^latiou to their Atomicities, iv. 1274. Atoms {^tio Ahsh-itctX vi. UU. W. C Oolitic and Paleozoic Forms of Veirotation, x. 220. Wilson. A., Colonial Or,>ranisms. ix. 50S. John. Ploii-hs and Plonirhing. Ancient and Mixltru. i. 'Jiio. C W., Ordnance Survey oi Sinai, VI. 8o. Wimshnrst. J.. EKctrical Iiillnence Machines, xu. oOO. presents Electrical Intluence Machines. X. 214: xii. 201. Wind applied to Strinj: Instruments. VII. 488. Winds, Laws of. vii. 40. Wines. Treatment of, i. 303; Acidity. Sweetness and Strtugtii of, 381. Wings of Birds, xi. 304. Wiseman, Carvliual. Points of Contact between Science and Art. iv. 0. Sliakespeare. iv. 470. Wi>licenn-;. Dr.. Keseaivh. s on ^Tiiscn- h\r Power, iv. t>04 ,t tttq. WohU r's iMiemical Work, x. 477. Wolf Kock l.iulith.nise. vi. 214. Wollaston, W.ll., Bust of. i>c. 2o0. Women, their Intluence on the Pn->grcss of Knowledge, n. oOl. Woodward. C. presents Polarising Ap- paratus, vii. 104. Woodv Fihre, iv. 400. Wright, A W.. Kesearclies o3. ; the Wave Theory, o02 ; Ilieroglypliical Re- searches, o74. Yttrium, xii. 40, 43. Zellf.k. on SiVrates' Damon, vi. 410. Zinc-Ethyl, its Powrr. iv. 311. Zodiacal Light, v. 104. Zooloirical Distribution, viii. 511. LOM>OS : PKINTE1> BT WILLIAM CLOWES AND SONS, LIMITED. STAMFORD STREET AND CHABISG CROSS. MBL WHOI Library - Serials 5 WHSE 00741 m •Mi :VV.iiaS&iUfiitSil3iiSfl£UU&