;7|^f^ft^i^^S^ ^iM, I gARSWELL Co, Limited S Bookbiud4>r». c TORONTO I PRINTKKS, I ■ I Law Hooks, A OF CAN/:: TORG NTO, Plainly Worded — Exactly Described, CONDUCTED BY MAJOR B. BADEN-POWELL AND E S. GREW MA 'Let Knowledge grow from more to more " — Tenw.son'. Volume I. JANUARY TO DECEMBER, 1904. NEW SERIES Volume 1. a london: KNOWLEDGE OFFICE, 27, CHANCERY LANE, W.C. {All Rights Reserved.] SEP 27 1968 y London ; King, Sell & Olding, Ltd., 27, Chancery Lane, W.C. r, k K' \y / KNOWLEDGE & SCIENTIFIC NEWS. 111. INDEX. The letter K before a number rejers to tlujtinuaiij itumber oj " KNowmDGE." A. PAGE Achromatic Condenser ... .Aeroplane, A Motor ... ... ... ... 3 ,, Experinientti at the Crystal Palace iii, 154 Agriculture, Recent Research in ... ... 43 ,, at the British Association ... 205 .■\ir, Electric Discharges in ... ... ... 17 " Airships, My," Book by Santos Uumont ... 133 .■\itchison Field Glass ... ... ... 101 Alligators ... ... ... ... ... ... 161 .Altimctre, The ... ... ... ... ... 17 Aluminium, Plating ... ... ... ... 176 .Ambergris, A Precious Product ... ... 71 Ancestry of the Elephant ... ... ... 11, 74 „ ,, Camel 25 ,, ,, Carnivora ... ... ... 61 .\ncient Calendars ... ... ... ... 1 .Animals, Rare, Living in London ... 59, 170, 258 „ Fasting 144 ,, Gluttonous ... ... ... ... 269 \nimated Photographs of Plants ... ... 83 .\ntelope, A Deer-like ... ... ... ... 124 Anthropology at the British Association ... 204 .Apes, Brain of Man and ... ... ... 97 .Arctic Exploration ... ... ... ... 191 " Argus," Attachable Mechanical Stage ... 47 .Armadillos ... ... ... ... ... 188 ,, Arnold, R. B., Book by ... ... 275 Asia, Central ... ... ... ... ... K.I. Asphalt -Mending ... ... ... ... 156 Asses, Wild ... ... ... ... ...222, 293 Association of Academies, The International... 132 .Astrographic Catalogue ... ... ... 123 .Astronomical Notes 8, 41, 70, 95, 123, 158, 186, 220, 241 ,, Society, R., of Canada ... ... 242 Astronomy in the Old Testament ... ... 234 .Ataxia, Hereditary ... ... ... ... 103 .Atlas, Photographic, of the Moon ... ... 40 Axis of the Earth, A'ariation of ... ... 171 Bacteria and Radio-activity Baden-Powell, Major, on Aeroplanes Badger, Duration of Pregnancy in the Balfour, Rt. Hon. A. J ,, Henry ... Barometer Becqucrel Rays Beetles, Colour-Pattern in Benham, C. E. , on the Super .Solid Bickerton, Prof. .A. W., on Explosion Bird Life ,, Migration ... Birds, Fossil Birkbeck College Blondlot " \ " Rays Blood of Men and Apes ... f Stars 127 'I. 154 16 197 204 77 140 4,S 261 244 42 41 241 18, 44 246 Borings on a Coral Island Botanical Notes 9. 43.. 7-. 97. >-5. i^9. 221, 243, 267, Botany, at the British Association Bredechin, Prof. T., Death of ... British Association, The ,, ,, Presidential Addresses Brook 's Comet Bryan, Prof. C. II., on .Stereo.scopic Pro- jection of the Light Cell ... Burnham's Measure of Double .Stars .. Burrowing Fishes Huxzard, Breeding of the ,, Rough-legged c. Cachalot Whales Calcium, and Hydrogen Flocculi ... .■•41, ,, as an Industrial Metal Calendars, .Ancient Camel, Ancestry of C;mals on Mars ,, Nicaragua, an Eighteenth Map of Cancer, Latest Discoveries Concerning ,, Problems Cape Jumping Hare Cathode Rays, Chemcal Effect of Ceylon Oyster Fisheries Chemical Conception of the Ether, Book by Prof. Mendeleeff ,, effect of Cathode Rays Chemistry, Modern A'ievvs of ... ... 35, ,, at the British Association Chess Chimpanzee, .An Intelligent ,, and Gorillas Chlorophane Classification of Reptiles Gierke, Miss A., on Modern Cosmogonies K. 6, 30, 80, 178, 21 Climates, Comparison of " Co;il Sack " in Cygnus Coccidai Cole, Greville .A., on the \"ital Earth Collier, J., on Variability in .Sociology Collins, !*., on Protective Resemblance of Insects ... ... ... ... 51, I Colour, Photography in .Natural ,, of \'ariable Stars ,, .Analvsis of. Book on ... ,, of lobsters ,, in birds ... ,, of nestling birds ,, in beetles I'A» ,, >, ,, Camel ... 25 i> ,. ,, ,, Carnivora 61 M ,, Fasting Animals ... . . 144 >» ,, Later History of the Horse 171 >f ,, Tibetan Animals ... ... 216 M. Magnetism, Terrestrial ... ,, Sunspots and Magnification in Microscopy Mammals, New ... ,, Fossil ,, of Central Asia Mammoth Skull in Kent Mantis Marriott, W., on Meteorology Mars, Canals on ... ... ... ••■37, ,, Observations on ... ,, New Chart of Marsupials, Evolution of Masscc, Geo., on the Influence of I'"uiigi Maunder, E. W., on Ancient Calendars ,, ,, Can.-ils of M;irs ,, ,, Is there .Snow on Moon ? ,, ,, .Solar Atmosphere ,, ,, .Snake Forms in C steliations .McClean, .\Ir. Frank, Death of Medusa of Lake Tanganyika ... .Mcndelceff, Prof., Book on Chcmic;il Cone tion of the Ether Metals, Action of Radium on ... Meteoric Observation Meteorology, Last Vear's Weather ... ,, Practical Meteors, Leonids Microscopical .Society, Roval Table' ...' Microscopy K. 20, 21, 47, 75, 104, 134, 164, 2, Migration, Bird ... Milne, Prof., on tiie Displacement of tlie ]\ Mites Monkeys and Altitutle ... ,, Brain of Mont Pelee, The Obelisk of Moon, Photographic Atlas of the ,, Is there .Snow on Mosquitos in England ... Motor Aeroplane, A ,, -Single-Phase Mouse, A New British ... Mummies, Natural 9 ... 96, ji)i 2 1 42 246 268 2.[f) 13 167 K. II , 21 75. 105 ,'<>.^ 225 24, 250, 306 42 )les 171 ...104, '34 <)6 97 3« 40 r,4 124 3 93 124 2fK1 N. N-rays, Phenomcn.-i National Physical Laboratory ... Natural History Specimens Nature Printing ... Nautilus and Flying Fish Nebula; ,, Forms of .\nd the Milky Way ,, In the Pleiades ... Nebulosities Round 7 Cygni New Genus, Botanical ... .Newton's Rings in Microscopical Objectives Nicaragua Canal, Old Map of ... Noble, Capt. William, Death of Nutcracker in Northamptonshire 18, 44, 92 102 72 23 238 l(>2 41 21 t 2^16 .•788 10 9 25' 1K4 98 VI. KNOWLEDGE & SCIENTIFIC NEWS. O. Obelisk on Mont Pelee 38 Obser\atory, Greenwich, Report on ... ... 159 ,, Harvard College ... ... ••. 241 ,, Lowell 24' „ Paris ■ -;43 • Old Riddle and the Newest Answer," bv John Gerard ... ... ... ... 98 Ore Finding by Electricity ... ... .. 157 Ormerod, Miss Eleanor, Autobiography . . 163 Ornithological Notes 98, 126, 160, 187, 221, 267, 292 Orthoptera, Preserving ... ... ... ... 47, 76 Osprey Plumes, Real and Artificial ... ... 128 ,, In Surrey ... ... ... ■. 268 Ovster, Pearl, Fisheries ... ... ... 6 P. Paca-rana ... Palolo Worm, The Panorama Military Telescope .. Paradise, Birds of, in England Parasitism, The Development of Patents, Recent ... . . . • ■•■ 23, Pearl Oyster Fisheries ... ,, Organs of Fishes ... Peat and its Mode of Formation Pelee, Mont Penguin, The Emperor ... .... Pericin, Dr. F. M., on Indigo Pheasants, Hybrid Photographic .Vtlas of the Moon Sun Photographs, Transmission by Telegraph ,, ' Animated, of Plants ,, Of Solar Granulations ... ,, With the Yerkes Telescope Photography of Electric Sparks ,, Registration of Star Transits by ,, In Natural Colours ,, Pure and .Applied 117, 146, 174, 219, 235, 262, Photometry, Solar and Stellar ... Physical Chemistry Book ,, Deterioration, Book on Physiology at the British Association ,, Primer of ... Plants, Animated Photographs of Plover Kill Deer Pond Life Tanks ... Porter, A. W., on the Conservation of Mass... Preserving Specimens for Microscope ... 47 Primeval Instincts Printing Telegraph Protective Resemblance of Insects Protyle : What is it ? Pvcraft, W. P., on Osprey Plumes (See Ornithological N Coloration of Nestlina; Birds Q- Qnaggas and Wild A.^jscs Quekett Microscopical Club (see under Micro- scopical Notes each month). 268 71 177 267 114 lOI 6 96 175 38 98 253 160 40 70 55 83 12 2 124 28 95 43 286 17 99 163 204 238 83 187 7fi 282 ■ 76 42 18 51 80 128 tcs.) 271 293 R. Radiation, A Novel Phenomenon 97 ,, In the Solar System 266 ,, Variation in Solar ... 186 Radio-activity ... ... ... ... 77, 07. 248 ,, Bacteria and 127 ,, Of Chemical Reactions 282 Radium ... ... ... ... 8, 77, ■'J7. 126 ,, Chlorophane and 72 ,, .-^nd Heat 98 ,, Emanation ... ... 126 ,, Book on ... 133 ,, Electroscope 184 Rainfall Last Year 24 Ramsay, Sir W., on New Gases and Radium 8 Ravens Nesting in Captivitv 126 Rays, " N," ' 18 ,, Thought ... ... ... 245 Reade, T. Millard, " The Evolution of Earth Structure "... 9 Recording .Apparatus, Electric ... ... ... 24 Reptiles, Fossil . . . ... .:. 15- 162 ,, Classification of ... 16 Resemblance of Insects ... ... 51. 137 Roberts, Dr. Isaac, Death of ... 184 Royal Society Medals ... 295 Rubber, A New Plant ;. 9 s. 220, 266, St. Louis, Science at ... ... Salmon in Fresh Water ... Saltness of the Dead Sea Sampson, Prof. R. A., on the Mechanical State of the Sun ... Satellite ,, Jupiter's Fifth ,, Saturn's Ninth Saturn School on the Ocean -Scintilloscope Sclater, Dr. P. L., on the Thylacine ... ,, ,, Cape Hare ,, ,, Grevy's Zebra Scott, Mrs. D. H., on Photographs of Plants Sea, Saltness of the Dead Sea Sickness, Apparatus for Preventing .Secchi's Fourth Type of Stars . ,, Third Type ,, Secondary Battery, Patent Sedgwick, .\dam ... -Selenium, Conductivity of Sensitive Plant, Photo of Shackleton, W., " The Face of the Sky " each month. Shark, An English Shenstone, W. .'\., on Radio-activity ... •■•77' Shimose Single-Phase Motor Smell, N-rays and Smithsonian Expedition to Observe the 1900 Eclipse Snake Formation in Constellations •••227-, ,, Salamander ... ... ... ,, Stories ... ...... ... ... 72 ,, Cannibalism in 222 .Snow on the Moon? Is there ... ...■ ... 64 296 223 10 119 287 159 20, 266, 287 91 264 236 59 170 258 83 10 160 70 158 24 55 85 158 93 92 159 301 293 KNOWLEDGE & SCIENTIFIC NEWS. Vll. Sociology, Variability in Solar-activity and Magnetism ,, Atmosphere ,, Eclipse of 1900 ,, Granulations ,, Parallax ,, Photometry ,, Radiation, Variation of . ,, Research Expedition Somerville, Dr. W. Sound of l*!xplosions Sparks, Electric ... Spectrometer Table, New Spectrum of Stars ,, .Analysis Spencer, Herbert, ,, Autobiography of Spider, Leg and Foot of Spinthariscope, The Spiral Structure in Hercules Star, Transits, Registration of ,, Double, Measure of ,, Catalogue ... ,, Spectroscopic Binary in Pegasus ,, an Interesting" Variable . ,, Colour of \'ariable ,, of Secchi's Third Type . ,, ,, Fourth Type ,, Binary Stars, Radial Velocities of ,, Secchi's Fourth Type . ,, I'^xplanation of Stellar Magnitude of the Sun . ,, Photometry Stereoscopic, Projection of the Kisjht-Cell ,, Single Lens ,, Projection Stimulus and Sensation ... Stork Breeding at Kew Strahan, Aubrey ... -Strutt, Hon. R. J., Radium Electroscope Sun, Stellar Magnitude of the ,, Mechanical State of the ,, Photographic Atlas of ,, Electric Equilibrium of the Sunspots ... ,, and Terrestrial Magnetism .. ,, Variation in Latitude 15c), 181, 237, Super-solid, The ... Sverdrup, Otto, Book on the Arctic ... T. Telegraph, Printing ,, Transmitting Photographs ,, Wireless Telephone, Wireless Telescopes, Large v. Small ,, "Panorama" Military I'AGi-; 214 291 150 159 122 ■5^ 1" 186 187 206 94 16 159 284 ■ 1.'? 116 148 68 9 95 96 123 12^ I.S8 186 158 1 8 70, 12-? 26'l 9 17 q2 127 2g6 89 160 201 184 9 119 70 186 I.ST 96, III) 265, 290 4.=; iqi 18 56 72 160 K. 12 40 Teletyping Temperature, Mean Thylacine, The Tibetan Animals ... Touracon, A Nestling Traction System, Electric Transmission of Photographs by 'lelcgraph Turbines, Patent ... Turkeys, Brush, Breeding in Conlinenicnt V. i'.\r.K IS 24 .S9 216 292 49. 73 23 24.3 Variability in Sot-iology ... 214 W-locities, Kadi:il, of Stars 70 of I he Piei.ides TS7 X'enus, Observ.-itions on 41 \"ipcrs' Poison 1 89 X'olcauic Obelisk ... 38 . iCk), w. Wave Measurement, Ivlectric ... Weather, Last Year's ,, Plant, Photo Weeds, dried, as Drugs Whales, Cachalot ,, Collisions ,, Destruction of Wind-driven filectricity Works Wireless Telegraphy Experiments ,, Telephony Wolf, Dr. Max, Xelnilosities in Cygnus Woodward, A. S., on the Ancestry of Elephants ... ... ... II Worm, The P;ilolo ... ... ... ... 71 Wright's Motor .Aeroplane ... ... ... 3 Y. ^'cndell, Mr., Observations of the Colour of Stars 186 \'erkes Observatory ... ... ... ... 124 Voung, Prof. Svdnev ... ... ... ... 201 131 24, 50, 76 84 1 66 42 96 125 36 72 246 10 •77 z. Zebra Training ... ... ... ... ... 97 ,, (irevy's ... ... ... ... ... 258 Zittel, Karl von, Death of ... ... ... 16 Zodiac, Change from Taurus to Aries .... 123 Zoo, Rare Bird at the .. .. ... ... 124 Zoological Notes 15, 41, 70, 96, 124, 161, 189, 222, 246, 268 Zoology at the British .As.sociation ... ... 202 Vlll. KNOWLEDGE & SCIENTIFIC NEWS. ILLUSTRATIONS. PAGE Aeroplane.. III, ii3> 154-5 Animated Photographs of Plants 83-86 Arctic Exploration 192 Rricteria and Radio-activity 127 Ralfour, Rt. Hon. A. J., Portrait 197 „ Henry, Portrait of 204 nirds, Nestling ... 273 Biitternies " ... 52, 137, 210 Camel, Ancestry of the ... 26 Cancer, Discovery 15. .^9 Capo Jumping Hare 170 Carnivora?, Ancestry of the 61 Chimpanzis and Gorillas 300 Constellations, Snake Forms in 227-9 Coral Island, Borings on 33' 34 Crystals, The Birth of 183 Darwin, Mr. Francis, Portrait ... 205 Dolls of the Tombs 185 Electrical Ore Finding ... 157 Elephants' Ancestry 11-14 Eliot, Sir John, Portrait 200 Flowers, " Physiotype " 239 Fossil Coal ... 305 Fungi ...141, 231, K. 3 Hi^reford, Bishop of, Portrait Her.schel Obelisk Horse, Bones of ... Indigo Plants Insects with Terrifying Masks Jupiter Kummeter Lamb, Prof. Horace Lunar Apennines (Titles in heavy type are those of whole page Plates.) Mars Meteorological Charts .. Mont Pelee, Obelisk Nebula; of the Pleiades Nebulosities in y Cygni Osprev Plumes Ovster Fisheries ... " Panorama " Military Telesccpe Parsons, Hon. Charles, Portrait of Peat and its Formation ... Photographs of Electric Sparks Printing Telegraph Radium and Radio-activity Resemblance of Insects PAGE ... 67, 87 168-9 ... opp. 38 289 opp. p. 10 129 7 177-8 203 '75 29 19 77. 107, 283 51-55- 137-9 206 290 ... K. 17 253 208 opp. K. 8 245 199 opp. 64, 65 Sherrington, Prof. C. S., Portrait Single Phase Motor Smart, Prof. William, Portrait Somerville, Dr. William, Portrait Spider's Leg, magnified... Stereoscopic, -Single Lens Pictures .Strahan, Aubrey, Portrait Sun Spots. Sunspot, Great, of 1903 Telegraphic Transmission of Photographs Thylacine, The Tibetan Animals ... Wind-driven Electricity Works Wright Aeroplane Young, Prof. Sydney, Portrait .. Zebra, Grevy's 205 93 203 206 opp. 148 127 296 201 121 151-2 56 60 216 37 4 259 Jaxvary. 1904.] KNOWLEDGE. Founded by RICHARD A. PROCTOR. Vol. XXVII.] LOXDOX: JAXUAEY, 190J.. [No. 219. CONTENTS. P*OK 1 Central Asia and Tibet Fungi as Links in the Chain of Life. — I. The Nature, Habitats and Distribution of Fungi. My G. M.^ssbe. {IllKslrated) 3 Modern Cosmogonies. VI.— World Building out of Meteorites. By Agnks M. Clkrkk ... . ... 6 Jupiter and His Surface Currents. By the Rey. T. E. R. Phii.i.ips, m..\., f.b.a s. (Illustrated) (Plate) ... ... 8 The Shower of Leonid Meteors in 1903. By W. F. Dbvninq, r.B.A.8. ... .. ... ... . .. 11 tetters : L.KBGE verfus Small Telescopes ix Planetary Work. By A. Stanley Williams 12 The Obchid Cephalantheba Geandifloba. By C. E. Clabk. (lUmtrated) 12 A Foo Bow. By Maey Fraseh 13 Obituary;— Hebbebt Spencer 13 British Ornithological Notes. Conducted by Haeet F. WiTHBRBY, E.Z.8., M.B.o.r. ... ... ... ... ... 13 Notes 13, 22 Notices of Books 14 Books Receited ... ... ... ... ... ... 16 The Ancestry of the Horse. By R. LYDEkKEs. (Illux- trated) 10 Microscopy. Conducted by F. Shillfn-oton Scales, f.b.m s. 20 The Face of the Sky for January. By W. Shacklbton, P.R.A.s. {Illustrated) ... •■ .. ... .. ... 22 Chess Column. By C. D. Locock:, b.a 23 CENTRAL ASIA AND TIBET.* Dr. Sven Hedin is without doubt the most remarkable explorer now living. From an early age he adopted exploration as a profession, and Asia as a speciality. His training to this end has made him able to perform single- handed most extensive journeys into unknown parts of Central Asia, which have yielded splendid scientific results. His organising powers are great. As a topographer lie has no rival, while he is also able to undertake successfully the work of a meteorologist, geologist, biologist, ethnologist, archseologist, and many other specialities, and thus is • " Central Asia and Tibet. Towards the Holy City of Lassa." By Sven Hedin. (Hurst & Blackett.) 2 toU. Illustrated. £2 2b. net. empowered to give an accunite picture of the cdiuitry through which he travels. The scientific results of his latest expedition hiive still to lx> worked out, and their ])ul>lication in detailed form is, we are glad to say. assiu'ed. In the present volumes we havt! only the narrative of his travels, with an inkling of what is to come in the way of valuable scientific results. It is possible in the limits of this notice to give only a general idea of Dr. Hedin's journeyings. From the middle of 18;»;' to the middle of V.Wl he was travelling almost incessantlv, his various routes in Asia extending to a total of some "(;000 miles. TIm^ narrative of these journeys, contained in these two fine volumes of over (JOO pages each, is in the form of an orderly journal, solid with fact and detail, b\it at the same time vividly written, so that one's interest in the chronicles of each day's doings is held to the end. The narrative, in fact, not only gives a lifelike picture of the country through which the explorer i)assed, and of how he got through it, l)ut reveals besides many a deep insight into Asiatic character, while of his own character the author unconsciously draws a most in- teresting picture— great determination and dogged phutk, with now and again a susjiicion of rashness, untiring energy, a keen foresight, cheerfulness under all circum- stances, a singular humane and sympathetic nature, are among the characteristics displayed. In August, 1899, Dr. Hedin reached Kashgar, in Turke- stan. Equipping there a carefully-organized caravan, he proceeded to the Yarkand Daria, or Tarim, the great river which flows through the deserts of Eastern Turkestan. Here at Lailik began the first and perhaps most important part of his journeys. Converting with immense labour and great ingenuity a ferry boat into a floating residence and observatory, he committed himself to the broad waters of the lonely Tarim. The greater part of the first volume of the narrative is occujiied by an account of this almost idyllic journey. But it was a journey of great geographical importance for the hitherto little kno-ivn and badly-mapped Tarim is now, by the labours of Dr. Hedin, the best- mapped river out of Europe. For months, day after day, as the boat floated down the great river, the author sat glued to his table, mapping on a large scale every twist and turn of the stream, checking and recheckiiig his measurements, frequently measuring the depth and width of the river, and the velocity and volume of its waters. As long as the boat was moving there was no time for relaxation. " I was never able to quit my post for an instant to stretch my legs. VVe hardly ever travelled more than ten minutes in a straight line Hence I had to keep my eyes upon the compass." But if the work was hard, and perhaps many would think monotonous, Dr. Hedin was enchanted by this voyage. The scenery in parts was beautiful. " The forest stretched right d(jwn to the very brink of the river. High up on the sky-line ran the green coping of the poplars' crowns, making a dense curtain of foliage which seldom allowed a glimpse of the tree-trunks to o-leam between-green, l)ut green shot with various shades Sf rich brown, so rich that they would have been harsh luid their effe(;t not been softened by the hazy sky behind them." But at other times the country through whicli the river ran was utterly barren, the soil being sand. And as the Great Takla Makaii Desert was reached " we were engulfed in that awful Asiatic silence — a silence as of the dead. No greeting came to meet us from the heart of the desert. The river— the river alone— sang its rippling song to the irrespimsive sand Very strange to be crossing one of the earth's greatest deserts KNOWLEDGE. [January, 1904. by water ! Not so very long ago I had nearly died there for want of it." And not only did the scenery change as they drifted on, but the fiery heats of summer were succeeded by the violent autumn storms, and then the winter crept steadily and remorselessly on. The surface of the river one morning was spangled with patches of ice. Then a fringe of ice crept out day after day further from the banks, and the air was full of murmurs from the grmiliug ice, but there was still time to go many miles before the passage was blocked completely by the ice. Then winter quarters were formed, and the caravan, which had made the long journey by land, was successfully joined. " Never," writes Dr. Hedin, "was a journey of that magnitude carried through so comfortably and so successfully." And we believe him, for with little danger and with no great difficulty for so resourceful and intrepid an explorer, a thousand miles of a practically unknown river was most minutely investigated in the space of some three mouths. Dr. Hedin is not one to rest on his oars. No sooner had he got his winter quarters comfortably arranged than he started out on a perilous journey southwards across the Takla Makau Desert to Cherchen, situated on the river of that name. This desert journey in the middle of a very hard winter, with temperatures of many degrees below zero, and frequent blinding suow-strirms, was a very trying piece of work, but it was accomplished with the loss of only one camel. After an excursion to the south-west from Cherchen, which involved a very cold ride of 20U miles. Dr. Hedui brought his caravan back to his winter ijuarters, travelling for the most part by the ancient bed of the Cherchen River. Meanwhile his head-quarters camp had become "an important market, well known throughout all the Lop country, and immediately outside its precincts there grew up a ring of small ' suburbs,' where tailors, smiths, and other handicraftsmen came and plied their several trades." And Dr. Hedin became quite a king in the Lo]) country, and was able to set right many injustices to the poor. In the springs of 1900 and 1901, Dr. Hedin turned his attention to the district of the famous Lt)p-nor and its sister lakes. His work here was very important and interesting. The Tarim empties itself into the great depression of the Lop Desert. It has been long suspected that the lake into which this great river discharges its waters has shifted from time to time. Dr. Hedin has amply proved this to be the fact, by an examination of the Kara-Koshun Lakes, into which the river now empties itself, and by a careful survey and levelling of that part of the desert in which the old lake was suspected to have existed. Moreover, he found that the present lake was actually travelling back to its old bed. " Nor is it sur- prising," he writes, " that such should be the case in this desert, which my survey pi-oved to be almost pert'ectly horizontal. While the Lake of Kara-Koshun, which had existed a long time in its southern half, was being filled up with mud, drift-sand, and decaying vegetation, the arid northern half was being excavated and blown away by the winds, and thus being hollowed out to a deeper level. Now these changes of niveau are determined by purely mechanical laws and local atmospheric conditions ; con- sequently the lake which serves as the terminal reservoir of the Tarim system, must be extremely sensitive to their influence. . . . Then vegetation and animal life, as well as the fishing population, inevitably accompany the water as it migrates, and the old lake-bed dries up." In connection with this last observation, Dr. Hedin made a most important historical discovery. In the spring of 1900 one of his men found by a lucky chance, in the middle of the desert, some old ruins. The next spring these were searched for and rediscovered. The material obtauied from them has not yet been fully worked out, but enough has been done to show that this spot, on the shores of the ancient Lop-nor, was the site of Lou-Ian, an important country in olden times, since it was situated between the great northern highway and the great southern highway from China to Europe. Long known historically to the Chinese, its position hitherto has never been accurately fixed. "How difterent, how exceedingly different this region was now compared with wliat it must have been formerly! Here was now not a single fallen leaf; not a single desert spider. . . There was only one power which brought sound and movement into these dreary, lifeless wastes, namely, the wind. ... I can imagine how beautiful a spot it was — the temple .... embowerered amid the shady poplar groves, with an arm of the lake touching it. . . . Round about it were the scattered villages. -. . . Southwards stretched far and wide the bluish-green waters of Lop-nor, set about with forest groves. . . . Look upon that picture and then look upon the picture of the scene as it is now ! Au endless array of cenotaphs ! And why is this ? It is simjily because a river, the Tarim, has changed its course." For an account of the many difficulties, hardships, and dangers that the explorer and his party experienced in the explora- tion oE this great desert and the surrounding country, we must refer our readers to the traveller's own modest but giaphi<- account. Dr. Hedin's ne,Kt and last great journey was an exceedingly long and trying one across the northern part of Tibet. For this journey he organised an immense caravan of camels, horses, and asses, but so difficult was the country, and so great were the hardships, chiefly on account of most of the time being spent at great altitudes, that very few of these animals survived, while several men died from the same cause. Dr. Hedin is not one to make much of hardships and difficulties, and his statement with regard to this journey is therefore significant. " For my part," he writes, " I would rather cross the Desert of Gobi a dozen times than travel through Tibet once again in winter. It is impossible to form any conception of what it is like ; it is a vei'itable via dolorosa .' " And we might add that there would have been little ciiauce of any less hardy or experienced traveller getting through at all. During this journey Dr. Hedin made a ]ilucky dash towards Lassa in the disguise of a Mongol pilgrim. But the Dalai Lama had got wind of his big caravan far away in the mountains, and he was stopped veiy firmly, but certainly not unkindly, on the threshold almost of his goal, and eventually escorted back to his caravan. After this the Tibetans continually escorted the caravan, keeping a small army on its flank, and effectually preventmg the explorer from going to the south. In view of our present advance into Southern Tibet, it is of interest to note that Dr. Hedm considers that the Tibetan's " policy of isolation during the last half century or so has not been dictated by religious, but by political motives. Their tactics, peaceful, but so far successful, have aimed at guarding their frontiers against Europeans." None but Europeans are tabooed. " Still Tibet will have to meet her destiny," says the author, and the day now seems near at hand As to the narrative in general, we may say that it is a most engrossing account of a very remarkable series of explorations. The book is well produced in every way. It has most excellent maps, and the illustrations from the author's photographs (over which he took the greatest possible pains) and sketches are exceptionally good. — ■ H, F. W. 1904.] KNOWLEDGE FUNGI AS LINKS IN THE CHAIN OF LIFE. I.— THE NATURE. HABITATS, AND DISTRIBU- TION OF FUNGI. By G. Jl.vssEE. Fuxr.t iiulnde the mushrooms ami to.ulstools, as well as moulds, mildews, trutHos, puff-balls and yeasts, and number altogether between fifty and sixty thousand different kinds. It is only by eomparins: thoir modi' of life with that of other groups of plants that tiie true nature of fungi and their special chanicteristios can be clearly understood. Flowering plants, ferns, mosses, seaweeds and lichens, in fact all plants with the exception of fungi, possess chlorv>phyll ; owing to the action of which they are enabled to use c-arbonic acid and other inorganic substances as food. Now the absence of chlorophyll must be considered as the most distinctive hall-mark of the fungi, and its absence implies their inability to utilize inorganic sub- stances as food. This feature places fungi on a par with animals, inasmuch as both agree in requiring organic food. This fact is obvious in the cuse of those fungi that develoji as parasites on living plants, as the destructive rusts and mildews on wheat, barley, and numerous other plants, both wild and cultivated. Neither would anyone doubt the statement in the case of fungi growing on, and consequi-ntly obtaining their food from rotten wood or dead leaves. The case is not at first sight so evident, where fungi, as the common mushroom, spring directly from the ground ; when it might be supposed that the fungus obtained its food from the same source as the grass growing around it. Careful examination, however, would reveal the fact that the spawn of the mushroom derived its food from the decaying portions of grass ane carried by wind or other agents. This is not so with fungi, which, for the reasons already stated, require organic focxl. There are no other fast lines between fungi and other members of the Vegetable Kingdom, all other distinctions being only differences of degree. Taking structure, we find that the characteristic unit, a cell with a well-defined wall or enclosing membrane, forms the groundwork of fungi, exactly as m all other plants, only in fungi the com- ponent cells are not differentiated into what are known as vessels, cork-cells, bast, &c., as in the higher plants. The reason for this absence of specialized structure in the fungi is the comparative absence of division of labour in these plants as compared with ferns and flowering plants. To understand this point of difference it must be remem- bered that in all except the very simplest of plants, which often consist of a single microscopic cell, there is a well- marked division into a vegetative and a reproductive stage; and even in the simple one-celled plants alluded to above, the one cell constituting the individual spends the first period of its existence as a vegetative, and tin' last part as a reproductive body. By the vegetative portion is meant all structures and work done for the welfare of the iudividual ; whereas the reproductive phase is entirely for the pur|)o.S(' of pro- ducing other individuals of the same kind, usually from seeds. Now if we take an oak tree as an example of one of llie chlorophyll-bearing jilants, the root, trunk, branches aud leaves, in fact every part except the flowers an). The part above the ground-line is the reproductive portion ; tile part below is the vegetative portion. Natural size. The ligureon the right shows two basidia bearing four spores each. Magnified .500 times. individual tree under consideration. As the oak lives for many years, the division of labour, or different kimls of work necessary to enable it to do so, are many aud varied. Of primary impt)rtance is a special arrangement for obtaining food from the air and the soil, converting the same finally into parts of the tree, and enabling the food to spread to every growing portion of the plant. Then, again, certain portions of the structtu-e are told oft' for the purpose of giving strength to the whole fabric, so that t he tree can withstand the force of the elements. As there is a limit to the life of the oak tree, in common with every other living organism, some provision is necessary for the continuance of the same kind of tree in the future. This necessity is provided for by the production of flowers ; these in the case of the oak eventually give origin to acorns, or seed, which in due course develop into other oak trees. This represents the reproductive cycle of the oak tree, and it will be remarked that, so far as volume KNOWLEDGE. [January, 1904. is eoncerued, it is very small compared to the permanent vegetative jx>rtion of the tree. Now, as a rule, in fungi the above proportions of the vegetative and reproductive portions of the plant are reversed as compared with the oak tree ; in other words, the reproductive portion of a fungus is much larger, and also more conspicuous than the vegetative portion. fihlM^. Fia. 2. — A second type of Basidiomyeetes {Clavaria aliefina). The entire branched portion ia covered with basidia bearing spores. Common in our pine woods. Natural size. If we take as an illustration the common mushroom, the aspect of which is familiar to most people, tlieu what is presumably considered to represent the whole plant — namely, the stem, cap, and gills— only in reality represents the reproductive portion of the fungus, being, in fact, the exact equivalent in function of the flowers in the oak ; the equivalents of seeds, called spores in the fungi, being produced on the surface of the gills. On the other hand, the vegetative portion of the mushroom consists of the comparatively small portion of white thread-Uke spawn or mycelium ramifying in the manure or other substance on which the fungus is growing. The same arrangement of parts is practically true for all other fungi ; the portion visible to the naked"eye, how- ever varied its form or colour, represents only the repro- ductive portion ; whereas the vegetative part is buried in the substance from which the fungus obtains its food. The popular belief that the mushroom and other fungi grow in a single night is not correct; it is quite true that when the mushroom has reached a certain stage of develop- ment, one or two days suffices for it to attain its full size afttr it appears above ground. Before this final spurt is reached, however, the baby mushroom has been growing for some weeks, and undergone various changes of struc° ture and development before it emerges above-ground. A little thought will recall to mind the fact that mushrooms do not spring up \vithin two or three days after the forma- tion of a mushroom bed, but several weeks elapse before the mushrooms are ready for the table. As to the origin of the fungi, the opinion held at the present day is that they originated or evolved from the algae or seaweeds, or their freshwater representatives. The most primitive groups of fungi are aquatic in haltitat, and closely resemble in structure certain algse ; in fact, at the beginning of the fungal group a fungus was an alga devoid of chlorophyll, the parasitic habit adopted by the pioneers of the fungi enabling them to dispense with this green substance. The sequence of evolution from these primitive types of fungi to the most modern members of the group — the agarics or gill-bearing fungi, and the puffballs — is fairly complete, and in evidence at the present day. Fio. 3. — A third type of the Basidiomyeetes (Dictyophora phalloidea). The entire upper portion is enclosed in the hollow covering or volva, until the spores are mature, when the stem elongates and bursts through the volva, and the crinoline-like network expands to form a landing-stage for insects, who devour the slime containing the spores, which is produced on the dark upper portion of the stem. Natural size. Not uncommon in Brazilian and other tropical forests. On the other hand, had the agarics and puffballs only been met with at present, the true origin of the group would never have btea suspected, so completely have all ti-aces of primordial structure and afinuity been effaced, Jantary, 1904. KNOWLEDGE combined with a complete loss of all trace of sexual reproiliK'tion. The iiiiinv causes combined to effect this remarkable chauge cannot be discussed here ; suffice it to say that the transition from an aijuatic to a terrestrial habitat is a main factor. The fuuiri are primarily divided into two groups, dej^iending on the mode of oriirin of the spores or reproductive bodies. lu the first or older group, dating from their secession from the alg;e. the spores are produced Inside sjiecial cells called axci, and the s[>ores are leclinically described as axcosjiores. In the older representatives of this group, that is those nearest to the alga-, there is a distinct motle of sexual rej>rodiictiou, in many instances indistinguishable from that presented by many alga;, but as the members invaded dry land tlie .sexual mode of reproiluction gradually disap|>eared, and is now com- paratively rare ; nevertheless the same general form of spore-producing structure is maintained. Now as these f uugi became more ;iiid more accustomed to existence on dry land, a most important addition to their meaus of reproduction gradually evolved. This consisted in the development of secondary kinds of rejiroductive bodies, technically called conidia. Now conidia more or less resemble ordinary spores in structure and appearance, but differ in not being a sexual product. This group of fungi, collectively known as the Ascomy- cetes, inchides many thousands of different kinds, large muiibers of which are very minute, and known only to those specially interested in the study of the fungi. Among kinds belonging to this group, and fairly well known, may l>e enumerated the Morels. Truffles, Yeasts, and certain of the minute fonus popularly known as moulds and mildews. The second large group, called the Basidiomycetes, have the spores borne on the surface of special cells called hamdia, hence the spores are spoken of as basidiospores. In this group there is no vestige left of the sexual mode of reproduction. The representatives of this section are usually much larger in size than those of the Ascomycetes, and include such well-known forms as the common mush- room, toadstools, puffballs, and the woody, bracket-shaped or hoof-shaped fungi growing on trees. It has already lieen stated that secondary forms of fruit are produced by fungi, but it is necessary to enter more into detail respecting this matter, as the extremes to which this idea is carried out in certain groups has no parallel elsewhere in the vegetable kingdom. In some fungi the different stages which together form the complete cycle of development are as different iu general appearance and relative size as that between a lK>ppv and an ash tree. Not only is this the case but the various forms usually grow at different periods of the year, one may be an annual and the other a perennial condition ; and, finally, when parasites, the forms may grow on different kinds of host-plants. As an instance of such multiplicity of forms repre- senting phases in the life-cycle of an individual, may be mentioned the common and very destructive wheat rust. The spring stage of this fungus appears under the form of clusters of miniature cups with frmged edges, filled with orange spores, on living leaves of the barberrv'. The spores of this form are scattered by wind, and those that happen to alight on a blade of wheat soon germinate and enter the tissues, and in course of time produce minute streaks of a rust colour on the surface of the living leaf. The spores of this second condition, dispersed by wind, inocu- late other wheat plants, and as the spores are produced in rapid succession throughout the summer, it can be readily understood how quickly an epidemic of disease can spread after a parasitic fungus has once secured an entrance. Towards the autumn, a third form of fruit is produced on the fading wheat leaves, (piite dilTereut in appearance from either of the two stages previously tnentioned. The spores of this third stage are called renting apores, Ijecause they remain unchanged until the following spring, when they germinate and iuDculate young barberry leaves, which results iu the provelo|iniout is not even ap}>roxiinately followed l>v ooinets. It would be pt)ssible only if they were isolated in space, and. in point of faet. their revolutions roiuid thosuuareof overwhelming importanee to their destinies. The suu"s repulsive energy eauses theni to waste aud diffuse with expansion of splendid plumage. Under the sun's unequal attraction at close quarters they are subject to disruption, and the upshot of the tidal stresses acting upon them is the dispersal of their constituent particles along the wide ambit of their oval tracks. We are, however, invited to look further afield. C'ometary meteor-swarms may be only miniature specimens of the contents of space. Why should not remote sidereal regions be thronged with similar assemblages, colossal in their jiroportions, countless in number? And may they not supply the long-sought desideratum of a suitable "world- stuff" for the construction of suns and planets? From some such initial considerations as these. Sir Norn\an Lockyer developed, in 1887, an universal Meteoritic Hypothesis, designeil on the widest possible lines, based on promising evidenc«, and professing to supply a key to the baifling enigma of cosraical growth aud diversification. The meteoric affinities of comets formed its starting point ; comets were assimilated to nebulw ; and from nebuhe were derived, by gradual processes of change, all the species of suns accessible to observation. The view was of far-reaching import and magnificent generality, but its value avowedly rested on a marshalled collection of facts of a special kind. In this it differed from the crowd of ambitious speculations regarding the origin of things by which it had been preceded. In this, it attained an immeasurable superiority over them, if only the testimony appealed to could be proved valid. Indeed, it is scarcely too much to say that, whether it were valid or not, the mere circumstance of having called the spectroscope as a witness in the high court of Cosmogony constituted an innovation both meritorious and significant. The spectrum of the nebula; was a standing puzzle. A theory which set out by making its meaning plain secured at once a privileged position. This was seemingly accom- plished by Sir Norman Lockyer through the means of some simple laboratory e.xperiments on the spectra of meteorites. Certain "low temperature" lines of magnetism given out by the vapours of ston}' aerolotic fragments were shown to fall suspiciously close to the chief nebular lines previously classed as " unknown." The coincidences, it is true, were determined with low dispersion, and were published for what they were worth ; but they looked hopeful. Their substantiation, had it been possible, would have marked the beginning of a new stadium of progress. Nature, however, proved recalcitrant. The suggested agreements avowed themselves, on closer enquirj', as approximate only ; magnesium-light makes no part of the nebular glow, and nebulium, its main source, evades terrestrial recognition. The light of cosmic clouds is, in fact, gui yeneris ; it includes no metallic emissions ; while the fundamental constituents of meteorites are metals variously assorted and combined. The decipherment of the nebular hieroglyphics was the crucial test ; its failure to meet it left the hypothesis seriously discredited ; for coincidences between spectral rays common to nearly all the heavenly bodies naturally counted for nothing. Yet the investigation had its uses. The energy with which it was prosecuted, the ingenuity and resource with which it was directed, told for progress. There has been a clash of arms and a reorganisation of forces. Thought was stirred, observation and experiment received a strong stimulus, fresh affluents to the great stream of science began to be navigated. Efforts to prove what had been asserted wert> fruitful in some directions, and the work of refutation had inestimabUi value in defining what was ailiuissible, aud establishing unmistakable landmarks in astrophysi('S. The discussion, however, threw very little light on the part played by m(>teorites in Cosmogony. Their world- building function remains largely speculative. Doubts of many kinds qualify its possibility, and lend it a fantastic air of unreality. 15ut this may in jiai't be due to a defect of imaginative power with which the universe is not con- cerned. Waiving, then, i>reliiuinary objections, we find ourselves confronted with the essential (piestion : Given a meteor- swarm of the requisite mass and dimensions, is there any chance of its coiulensiug into a planetary system ? Sir Norman Lockyer sot aside this branch of his suliject. His hypothesis was in fact " pre-iu^buhxr." He assumed that the small solir Darwin regarded the matter otherwise. It seemed to him possible to combine the postulates of the meteoric and nebular theories in a system planned on an original principle. F'or this purpose it was necessary to excogitate a means of rendering the kinetic theory of gases availabh; for a meteor-swarm. " The very essence," he wrote,* " of the nebular hypothesis is the conception of fluid pressuris since without- it the idea of a figure of equilibrium becomes inapplicable." M. Faye abandoned this idea; he built up his planets out of incoherent materials, thereby avoiding the incongruities, but forfeiting the logical precision, of Laplace's stricter procedure. Prof. Darwin consented to forfeit nothing; he stood forward as a syncretist, his object being to " point out that by a certain interpretation of the meteoric theory wo may obtain a reconciliation of these two orders tif ideas, and may Injld that the origin of stellar and planetary systems is meteoric, whilst retaining the conception of fluid pressure." For the compassing of this end, he ado[>ted a bold expedient. Fluid pressure in a gas is " the average result of the impacts of molecules." Fluid pressure in a meteor- swann might, he conceived, be the net product, of innumerable collisions lietweeu liodies to be regarded as molecules on an enormously inagiwAed scale. The sup- ])osition is, indeed, as Kepler said of the distances of the fixed stars, " a liig ])ill to swallow." From molecules to meteorites is a long leap in the dark. The machinery of gaseous impacts is obscure. It can be set in motion only by ascribing to the particles concerned properties of a most enigmatical character. These i>articles are, however, unthinkably minute ; and in sub-sensible regions of research, the responsibilities of reason somehow become relaxed. We are far more critical as to the behaviour of gross, palpable matter, because experience can there be consulted, and is not unlikely to interpose its veto. Meteorites are (hjubtless totally dissimilar from molecules, however many million-fold- enlarged ; and they would infallibly be shattered by collisions which only serve to elicit from molecules their distinctive vibrations. More- over, the advance of the shattering process would admit- tedly end the prevalence of fluid pressure. So that the desired condition, even if initially attained, would be transitory. There is, besides, a rait that at other times it was broad, and exhibited numerous condensations and white spots at its edges. It not infrequently happens that the general aspect of the planet undergoes a marked alteration even in the coiu-se of a single apparition. Thus Fig. (> represents a view of Jupiter in June, 1902, but l>y the latter part of the autumn the appearance of the disc had materially changed. The equatorial regions were intensely white — a very striking contrast to the rich warm coppery tone which was so marked a feature of the planet a few years ago — and the whole of the disc North of the N. temperate belt was deeply shaded with a delicate bluish grey. It is probable that some of the changes on Jupiter are of a cyclical or seasonal character. Mr. A. Stanley Williams in a valuable paper communicated to the Eoyal Astronomical Society in April, 1899, showed from a discussion of a large number of observations extending over many years that there is a remarkable variation in the colour of the two principal equatorial belts. Thus, when the S. equatorial belt is at a maximum of redness, the N. equatorial belt is at a minimum, or even bluish in tone, and vice versa. The mean period of these variations is found to be about twelve years, and as this corresponds \vith the length of a sidereal revolution of Jupiter round the sun, it is probable that the change observed is of a seasonal character. The maximum redness occurs soon after the vernal equinox of the particular hemisphere in which the belt exhibiting it is situated. In accordance with the interesting conclusion at which Mr. Williams has arrived, the N. equatorial belt has lately been in- tenselv red, and the S. equatorial belt almost colourless, except in the region immediately following the Eed Spot bay. JBut, perhaps, the most interesting and instructive feature hitherto observed in connection with Jupiter is the difference of speed with which his spots and other markings are drifting. So long ago as the latter part of the 17th centuri-, Cassini found that the markings in the neighbourhood of the equator performed a rotation in nearlv six minutes less time than was required by objects further north and south. Sir William Herschel, Schroter, and other observers confirmed this result, but as the outcome of the labours of more modem investigators, a considerable number of distinct currents are now known to control the movements of Jupiter's surface material. There can be no doubt that many recorded changes on Jupiter are in reality due to the great proper motions of the objects observed, which quickly cause them to become relatively displaced. r 1 ^ ' 1 m 1 1 ■ 1 ' 'I ' 1 L 1 ' 1 ^ ..\, W H Oh O a i<3 .- ;i 6 H 5 Janiaby, 1904.] KNOWLEDGE. With one or two exceptinns these surface cuvrciits are pretty constaut. Their velooily varies within eertaiu limits, and the hititude of their liouiichiiies is not always the same, but whenever detinite sj.H>ts or observable oondeusations appear their niovenieuts of rotation are nearly always found to conform more or less closely to the normal s]>eed of that latitude. In an article in the February. 1;10:5, uuuiber of PopnJar AstniiiDitiii, Prof. G. W. Houijh questions the existence of several of these surface currents. Consideriufr. however, the great mass of existing: evidence. I venture to thiuli that his conclusion is altogether unfounded, and that the reality of the currents is lieyond dispute. In January, 189ti, a valuable pajier bv Mr. A. S. WilUanis was published in the Monthly' Notlceg, E. A. S., "On the Drift of the Surface Material of Jupiter in Different Latitudes." In that paper Mr. Williams brought together the results of numerous eminent observers in various years, and gave a cleaj" account of nine separate and distinct ctirrents. It is worthy of m>te that the .arrangement of these currents, unlike those of the sun, is by no means symmetrical, neither is that of the two hemispheres the same. Moreover, the N. hemisphere contains in contiguity the swiftest and the slowest that have yet been observed. The following table shows the general arrangement of these surface currents, but it must be understood that. both the limiting latitudes and the rotation periods are subject to certain variations : — No. Latitude. Rotation Period. Kemarka. 1 I +80° to +31° 2 I +J4'' to +2*° b. m. s. 9 55 37-5 f9 ot .30 ) 1 9 56 30 ( From Polar Eesious to N.N. Temp. Iielt. From N.N. Temi). belt toN. uoiiiponent of N. Temi). holt. 3 +21° to +20° [? 48 49 30 J S. component of N. Temp. belt. 4 + 20° to +10° 9 54 32 N. Trop. zone and N. side of N. Eqna- torial Ijelt. 5 + l 9 .=» 37 Great Ked Spot. ti - 18° to - 36° 9 .55 18-5 From S. Trop. zone to S. Temp. zone. 10 -30° to -50° 9 55 6 S.S. Temp, belt, and bright zone S. of it. 11 - .^iJ" ± 1( 4o 23 Ed^re of S. Polar sbadinf^. These cun-ents must be discussed more in detail. No. 1. — There appears to be some uncertainty as to how far north this current extends. In 1888 and again in 18!<2, Mr. Williams observed dark streaks which extended into very high N. latitudes and moved in accordance with the tabulated velocity. Since then Captain P. B. Mt>lesw()rtli, who has made quite a unique series of .Jovian observations under very fine seeing conditions in Ceylon, Las succeeded in detecting a number of light and dark spots and streaks in the Polar regions. Amongst these, he found in I!t(»l five dusky streaks in about latitude •jO"', which gave a mean period of 9b. .56m. 37s. It is cjuite jjrobal)Ie that tb(> surface drift in these regions may be variable from year to year. More observations are much needed to settle tiie question of the minor, and at present doubtful, currents on the surface of Jupiter. No. 2. — The drift in this region is not constant. At times when the N. hemisjjhere is in a state of disturbance spots are liable to appear which have a decidedly rajiid rate of motion. As a general rule, however, it is found that markings in this neighbourhood exhibit the slowest movement of any on the disc. No. 3. — This is unquestionably the most remarkable, as it is the swiftest, of all the .Jovian currents. Our know- ledge of it has been well summavized by Mr. \V. V. Denning in a ]>aper eutitleil " On a i'l-obabie Instance of Perioilically Kccuirent Disturbance on the Surface of Jupiter," published in huiithlij Notices, K. A. S., Dccemlior, 1898. It ajipears that at intervals of little more than ten years spots hav<' fi-ecpiently ajipcared on the S. side of the N, temju'rate belt which have exhibited a velocity whicii is extraordinary. As already pointed out, this swift current exists sibal)le that the internal liody of the planet rotates iu a period somewhat longer than any markings we can observe — possibly in a period just a minute or so less than 10 hours. As regards the relative altitudes of the various markings, there seems good reason to suppose that the more swiftly moving objects are situated at a greater height than those which move more slowly. Of course, it must be remembered that the planet may have no solid or definite surface divided off from the vapours which form its belts and spots. It is highly probable^beariug iu January. 1904.] KNOWLEDGE. 11 uiiud the very low density of Jiipiter^tliat the whole globe is still in au intensely heated, semi-moUcu and viseous couditiou, and that what we see is but the outer- U'.ost shell of visible material. Professor Hough, in his important and valuable paper already ivferred to, suggests that the visible lx>uudary of Jupiter has a density of al)out oue-half that of water, is of the nature of a liquid, and that in it are immersed the Ked S]H)t and otliers wliose motion in longitude and latitude are slow and gradual, and whieh are tolerably permanent or long enduring. Ho considers that the equatorial and other belts-may be at the surface of this liquid or at a higher level than the Red Spot, and that the equatorial regions may Ix' concealed by overlying vapours at a much greater altitude, iu wliich openings and iiregular condensations give rise to the ap)>earance of white and dark spots. No doubt there are many interesting questions iu con- nection with Jupiter of whieh the solution must be left for future students ; but this much, at any rate, we may suggest with some contidenee : — We look at Mars and our own satelUte. iu them we see a forecast of physical con- ditions to which some day the eiirth must at least approxi- mately attain. We look at Jupiter, and, in the constant agitation of his heated glolje, we catch a glimpse, though on a giant scale, of our own world in the dim recesses of the j>ast. The accompanying diagram will enable the reader to 5 STcmperaIn Zone 5 TempcraJe Zone 5 Tropical Zone Equatorial Zone N. Tropica I Zone U Temperate Zone v- N N. Temperate Zone ^ S Polar Shadinq .^ S.Temperate Belt ^S.Tefnperate Bell SEquatonal Bell Equatorial Band N Equatorial Belt N Temperate Bel I N N Temperate Bell N Polar Shading identify the various features referi'ed to iu the above article and depicted in the illustrations. THE SHOWER OF LEONID METEORS IN 1903. By W. F. Denning, f.r.a.s. Tejipel's comet (1S66 I.) and the dense swanu of meteors in its contiguous region having passed through perihelion unobserved in 1899 the prospect of a fine shower of Leonids in 1903 appeared very doubtful. The meteors being, however, pretty thickly distributed along a con- siderable extent of the orbit, a fairly active recurrence of the shower was thought to be quite possible. Those oljservers who watched for its return on the morning of November Ifi realised their best expectations. The Leonids were aljuudantly presented, offering the test meteoric spectacle observed in England since 1885, and forming the prototype, if far from being the parallel, of the grand exhibitions of 1799, 1833 and 1866. The following are brief extracts from observations on the night following November 15, which have either been published or jirivately communicated to the writer : — ■ Backhouse, T. W., Sunderland. — Between 17h. 44ra.and 18h. 5m., about 83 meteors per hour. A Leonid fireball seen at 15h. 49m. The Leonids were bright generally. Of 65 recorded, 1 being = Veuus, -i = Jupiter, 15 = Sirius, and 26 brighter than, or equal to, 1st miguitude stirs. BrooJ:, C.L.,Miltliam, near Hitddcrsfiehl. —Btitwd'n \-2\\. and 15h. 30m., 52 Leonids were seen, after wliich clouds interfered. Verv brilliant Leonid at 13h. .59im., 2 x +. shot from 137'."" -^ 8^" to 133' ± 0'. Radiant of shower, Corder, 11., Bridijwaler. — Between 17h. and 18h., about 200 meteors per hour. Estimated position of radiant, 149= + 22". Cruee, W. de, E.teter. — Between 16h. 25ni. and 17li. lOiii., 108 meteors observed. Dennimj, W. F., Brislol.—The disphiy watched between 12h. and 18h. 15m. Maximum, 17h. 30m. to 17h. 45ni. 42 meteors. Radiant, 151° -|- 22=, about 6 degrees iu diameter. Ellison, Rev. W. F. A., Enniacortlnj.—lUi. 45iii. to 12h. 45m., 5 Leonids; 12h. 45m. to 13h. 45m., 16 Leonids; 13h. 45m. to 14h 45m., 36 Leonids; 14h. 45m. to 151i., 11 Leonids; loh. to 15h. 15m., 0 Leonids! Three fireballs seen, 13h. 40m., 153' + 43° to 185' + 28° (Taurid) ; 13h. 58m., 160=" + 18° to 166° + 12° (Leonid) ; and 14h. 19m., 210' -|- 65° to 273° + 58P (Leonid). livyal Observatory, Greenwich. — About 150 meteors seen, some as bright as Venus, the most prolific time being about IBh., wiieu they appeared at the rate of 100 j^er hour. Ilenrij, J. B., Duhliii.—h'J Leonids seen in 15 minutes preceding 15h., and 20 in 15 minutes following that hour. Between "leh. and 17h. 30m. observer had the impression that meteors were appearing at the rate of from 200 to 300 per hour. Herschel, Prof. A. S., Slotigh.— Not much short of 200- 250 meteors per hour. Brilliant Venus-like meteors observed at 16h. 31m., 17h. 33m., and 17h. 41m. Horner, Maiires, Taploiv.—THmng last hour of darkness counted S6 meteors, nearly all of which were Leonids. Johnson, Kev. S. /., '7?r((//./orf.— Several hundreds of meteors with the usual Leouid streaks and swift moUons must have passed across the whole sky. 16h. 27 \m., Leonid equal to Venus, 192° + 13° to 195° -|- 10'. KniijU, G. M., Lo/«/<>(';«.— Apparent maximum, 14h to 16h., with horary rate of 80 to 100 for one observer. Radiant, 149° + 22°. MrlLini, John, Lishurn.—Vih. 20m. to 14h. 20m., 20 Leonids, large proportion 1st magnitude; 13h. 45m., vivid green fireball from Taurus, 103° ± 0° to 112' - 6'. Moffat, A. G., Swansea.— Idh. 30m. to 18h., a brilliant display of large meteors ; some green-coloured, the major portion, however, electric blue. Service, R., Dumfries.— ISh.dOm. to 19h., 42 Leonids observed. Thonipson, G. C, CacfZi/f'.— Watching with a friend for several hours, only about 25 Leonids were seen ; a number of other meteors radiated from Auriga. Wriijht, F. H., Northamj)ton.—lbh. to 15h. 3Uui., 30 meteors; 15h. 30ia. to 16h., 60 meteors ; afterwards counted about 3 or 4 per minute. Maximum at about 17h. I3m., near which time 8 or 10 were several times counted in one minute, and 5 or 6 visible in the sky at the same instant. The general results may be summarized as follows :^ Time of maximum, November 15, 17h. 40m. Rate of apparition, 4 per minute for one observer. 12 KNOWLEDGE, [January, 1904. Point of radiation. loD^ + 22^°. Character of meteovr--, bright generally, with streaks and swift motions. Several Leonids and meteors belonging to contemporary minor showers were doubly observed, and their real paths have been computed. Among the latter there was a Taurid fireball, seen on November 16, about loh. 42m.. at Enniscorthy and Lisburn. It passed over the S.E part of . Anglesea at heights from 72 to 32 miles, with a velocity oF 23 miles per second. Radiant at 61 + 24^ A 2ud magnitude meteor appeared on November 15, loh. 59m.. directed from a radiant at 113° — 34^ and descending from 64 to 48 miles along an extended course of about 142 miles from over Sussex to Lincoln. Velocity about 19 miles per second, but the flight of the meteor seemed much retarded by atmospheric resistance, and at the end of its visible career, as observed at Bristol, it became almost stationary, its material and momentum being apparently quite exhausted. Hcttrrg. [The Editors do not hold themselves responsible for the opinions or statements of correspondents] > LARGE VERSUS Sil.lLL TELESCOPES IX PLANETARY WORK. TO THE EDITORS OF KNOWLEDGE. Sirs, — In the course of his interesting article on Saturn in the current number of Knowledge, Mr. W. F. Denning has referred to the well-known fact of large telescopes sometimes failing to show faint planetary markings that were visible in those of much smaller aperture. The mirkings in question usually appear to be those having a considerable apparent area and a more or less diffuse and indefinite outline, and I do not remember to have ever seen anv demonstration, either theoretical or practical, why markings of this nature sh'juld be any jdainer or better seen as a whole in a large telescope than in a small one. As regards minute details there can, however, be no question as to the superiority of the large telescope. But my present object in writiuor is to draw attention to the fact that the remarkal)le and instructive experi- ments on artificial markings, details of which have been recently published, seem to have an intimate bearing also on this question of the failure of large telescopes to show planetarv- markings visible in smaller ones. Particulars of one of these experiments having a special bearing on the sul)ject, made by Mr. and Mrs. Maunder, have been recently published in the Journal of the British Astrono- mical Association, Yol. XIIL, page 349. In this experi- ment two waved parallel lines when viewed at a distance of 130 feet, gave rise to the appearaace of a faint, diffused t)and. On approaching nearer, the experimenters found, to their evident surprise, that this appearance after awhile began to get feeble, and finally disappeared aUoijether at a distance of about 100 feet. Nothing could then be seen at the place of the two waved hues until approach had been made to very nearly 60 feet, when the lines rapidly became distinct. Now the employment of a larger aperture, and probably higher power, woidd no doubt be analogous in its effect to a diminution in the distance of the object, and hence, even assuming all other things to be equal, it does not seem diflicult to conceive the existence of a jiarticular kind of mai-king that would give rise to a distinct irapressiim in a small telescope, although nothing whatever could be seen at the same place with a large one. For instance, a number of faint, irregular, naiTow streaks crossing the bright equatorial zone of Saturn, perhaps analogous in their nature to the well-known equatorial "wisps" of Jupiter, and corresponding to the waved lines of the experimeut, might give rise to an appearance of alternate faint and dark areas or spots in a small telescope, though a " giant" telescope might fail to show anything whatever of this ap]:iearance. Yet such apparent markings or spots, although not strictly objective, would clearly have an objective basis, and heuce they would be suitable for determining the rotation period. A. Stanley Williams. Hove. 10 j3, December 1. THE ORCHID CEPHA.LANTBERA GRANDIPLORA. TO TBE EDITORS OF KNOWLEDGE. Sirs, — I have long had a thing to say about the fertilization of Cephilaufhera yrandifiora. and now that Mr. Praeger's hiterestinij article on Orchids has appearei dim't think I could fit it with a better time. Figs. 1 and 2 represent respectively the front and side views of the column of this plant, and are drawn from life. What are the threads that cross and re-cross and attach themselves not ouly to the stigma but to the front of the column and sides of basal portion of labellum, like the supporting strands of a spider's web r IE they are pollen Fig. 1. Fig. 2, tubes, why the cui-ious reticulation ? At first I thought the meshes were caused by pollen grains falling upon different parts of the column, whence they might germinate in any direction, but, in spite of Darwin, who says the grains " readily adhere to any object," I have tried to remove thein at all stages of development and not one grain could I get away, not even with the hairy edge of a piece of blotting paper ; now I am thinking that the earliest tiilies as they elongate may drag out and carry down from the poUinia grains that may be later in germinating, and would thus add meshes to the net. How does my supposition stand ': I should add that pollen masses almost entirely disappear when the threads are most numerous. 24, Iffley Road, C. E. Clark. Hammersmith, W., November 16th, 1903. Janvary, lOOL] KNOWLEDGE. in A FOG BOW. TO THE EDITORS OF KNOWLEDr.E. Sirs. — I slioiilil like to know if any of yo\ir roaders oau explain a strange phouonienou which I saw whilst travelling to Brighton from Hastings l)y train, about 7 o'clock ou the evening of the 30th of September last. Tbe night was hazv. and looking through the oiieu window I distinctly saw outlined against the sky a circle, or rather sux oval-shaped bow enclosing a long cross ; tbe lower ]iart of the vision being veiled in mist, the tones were neutral and soft, though clearly defined. It disappeared from view suddenly, and though I watched for quite half-an- Lour, it did not appear again. The train at this time was running through the flat marshy country, known, I believe, as Pevensey Level, therefore skirting the sea-shore. A picture of a similar appearauce in Whymper's "Scrambles amongst the Aljjs," recalled the circumstance to me. Beckley. Mary Frasek. i3'b\t\xatv. HERBEKT SPENCER. It is with deep regret that we record the death of Mr. Herbert Spencer, which occurred in the early morning of the 8th of December, at his house in Brighton. The last survivor of the many eminent men of his time, Spencer enjoyed the unique distinction of completing the stupendous task he had set himself as the purpose of his life, a task which oceuiiied him for the kmg [)eriod of thirty-six years (1860-1896). It is doubtful whether the history of letters contains a more remarkable instance of the amazing results of courage and tenacity than is found in the production of Spencer's Synthetic Philosophy. •• How insane ray project must have looked to oulooker.s," he says, when with his small resources frittered away, and his health |)ermanently im[)aired by overtax of brain, he was obliged to desist by reason of nervous breakdown actually before the first chapter of the first volume was finished. But the philosopher afterwards pursued his course undeterred, and he completed it with the ex[)ression of the modest satisfaction that losses, discouragements, and shattered health had not prevented the fulfilment of his long task. Born in Derby on the "i/th Ajjiil, 1820, the son of a teacher of mathematics, he shared w'ith John Mill the distinction of having his education directed entirely at home, although in Spencer's case an uncle assisted the father. But he never had any experience of school or college, and he early abandoned his profession in order to devote himself entirely to speculative thought. Spencer's long career is singularly uneventful in personal history, and it is certainly by no desire of his that the world knew anything about him. But as a frequent contributor to the Westminster Review, in his earlier days, Spencer was brought into contact with many of its then brilliant writers, and his striking originality was displayed in association with Hamilton and the two Mills. From the year 1861), when the philosopher first resolve. U. Caton Ifaigh re.;ords that he shot a young fem-ile of this Warbler .at Nortli Cotes on September 2uth. This is, I believe, the third specimen of the Barred Warbler which Mr. llaigh has recorded, and the eighteenth or so which has occurred in the British Islands. Sabine's Gull in Yorkshire {Zoologist, 19J3, pp. 3.")3, 301, 430). —The Rev. Julian G. Tuck has now recorded the occurrence of five (four adults) Sabine's GruUs in September and October last on the Yorkshire coast. This arctic species not infrequently visits our shores in autumn, but most of the previous records have referred to immature birds. Bare Birds in Kent and Sussex {Zoolor/ist, 1903, pp. -US- 12.5). — Mr. N. F. Ticehurst here tabulates the renv.irkable number of rare birds which it has fallen to the lot of ornitliologists in Sussex and Kent tj recori during the last twelve mmtlis. The most noteworthy of these have already been reported in these columns. All aintribntioas to the column, either in the v:aij of notes or phol(i(jraphs, should he forwarded to Harey F. Witiierhv, at the OJice of Knowledge, 326, High Holborn, London. i^otcs. Zoological. — According to recent information, the white rhinoceros (Rhinoceros simus), at one time believed to be all but extinct, appears to be comparatively common on tiie northern fmntier of the Congo Free Stale and the adjacent districts of the Sudan. The important anthropological and zoological collections brought home by Messrs. Robinson and Aunandalc from the Malay Peninsula are to be described in a new publici- tion, entitle 1 Fasciculi Maiayense>i. The first part, con- taining an account of Mammals, by Mr. J. L. Bonhote, has already been issued. Sixty-four is the approximate number of mammalian species included in the collection, of which eight are described as new. u KNOWLEDGE [Januaky, 190i. Great interest attaclies to the descriptiou b}- Dr. Mas Sclilosser, of Berlin, in the Ahliandhnigen, of the Eoyal Bavarian Aca<3emy, of a large collection of fossil teeth of mammals obtained from the druggists' stores of various jKirts of China, where they are sold as medicine. Many of these teeth— locally known as dragons' teeth— appear to be obtained from caverns, but others ]irobably come from the loess, or alluvium, while yet others are derived from older formations. Judging from the quantities in which they are sold in the bazaars, these teeth must exist in enornjous numbers in some parts of the Chinese Empire. The remains include those of deer, antelopes, three-toed horses {Hijjparion), rhinoceroses Chahcotherium, ances- tral forms of camel {PanicameJus), giraffes, okapi-like ruminants, pigs, hysenas, and sabre-toothed tigers One of the hy»nas {Hyxna gigantea) is by far the largest of its tribe," the upper earnassial tooth measm-ing tvro inches in length agamst one-and-a-half inches in the existing spotted species of Africa. Especial interest attaches to the ancestral camel, since North America is supposed to have been the original home of the Camelidas, and that continent was in close connection with north-eastern Asia in Tertiary times. Not less noteworthy is the occurrence of remains of antelopes of an African type, as well as of others alUed to the Indian nilgai. This seems to refute tlie theory that the antelopes of Africa originated in that continent (where the nilgai, which is a near relative of the kudu and bushbucks, is unknown), and to confirm Prof. Huxley's hypothesis that they are really immigrants from Asia. At the first meeting of the Zoological Society for the present session, Mr. O. Thomas described a gigantic rat from New Guinea, which he regarded as representing a new genus, and named Hyomijs meeki. A fortnight later, at the second meeting of the same liody, Mr. E, I. Pocock called attention to a remarkable habit of the Australian spiders of the genus Besis. These spiders live in the crevices of rocks between tide-marks on the shore, and by spinning a closely-woven sheet of silk over the entrance, imprison a mass of air in which they are able to live during flood-tide. Two interesting additions have been reeentlv made to the British vertebrate fauna. Till 1899, when it was detected on the coast of Brittany, the giant goby (Gohitis capito) was believed to be a jmrely Mediterranean fish. During the past summer, Mr. F. Pickard-Cambridge, by carefully searching the rock-pools, has discovered this fish on the Cornish coast. One of his specimens is figured in The Field. The second addition is an entirely new species of bank- vole (Evotomya skoinvreiisis), from Skomer Island, off the Pembrokeshire coast. According to its describor, Captain Barrett-Hamilton, this species differs from the common bank-vole (E.glareolus) not only in colour and size (being much larger), but also in the structure of the skull ; it belongs, in fact, to a distinct group of the genus. The description of this new species appears in the Proceedings of the Royal Irish Academy. The Americans are coutcmjilating a great undertaking ; nothing less than a complete biological survey of the Eastern Holarctic (or Palajatcticj region, that is to say, of the greater part of the extra-tropical area of the northern hemisphere. The proposed survey is to be undertaken on the lines of the one which is being brought to a conclusion in the United States, and it is calculated that it will take ten years to accomplish. The funds are to be supplied by the "Carnegie Institute. Such a survey, it is urged, would alone enable us to understand the true relationship of the fauna of Northern Asia and Europe to that of North America, and would likewise help to espilain the origin of both faunas. According to American ideas, the vast amount of material contained in the museums of Europe is of little or no use for such a purpose ; and it is in contemplation to collect the whole vertebrate fauna of this vast area section by section. If the project be carried tlu'ough, we may expect to be inundated with descriptions of so-called new species, comparable to the seventy which have just been named from the islands of Malaysia, by Mr. G. S. Miller, in a paper published in the " Mis- cellaneous Collections " of the Smithsonian Institution. Dr. W. G. Eidewood recently exhibited to the Linneau Society the frontal bones of a horse showing a pair of rudimentary horns, , very similar in position to those of some of the ruminants. In the opinion of the exhibitor, this feature can hardly be regarded as an instance of reversion, since none of the extinct ancestors of the horse, of which (as indicated in an article in our present issue) the .series is remarkably complete, show any traces of similar appendages. It is unfortunately not known whether the bony cores were covered in life with horn. This interesting specimen has been pi-esented by Mr. A. Broad, of Shepherd's Bush, to the British "(Natural History) Museum, where it is now exhibited. I^otfccs of Boons. '•British Mammals: An' Attempt to Describe and Illustrate the Mammalian Fauna or the British Islands fro.m the Comjiexcemext of the Pleistocene Period down to the Present Dav." By Sir Harry John- ston. (Hutchinson.) Illustrated. Price 12s. Od. — The author o£ this handsome addition to the ''Woburn Library" is apparently convinced that it is illogical to separate the animals of to-day from those of yesterday, and he accordingly includes in his account of the mammals of the British Islands not only those now to be met with there in a wild state, but likewise those that have been exterminated within the historic period, together with those extinct forerunners of the latest geological epoch. Whether this method is any more logical than the one which excludes extinct types may well be a matter of opinion, for if the animals of yesterday come witliin the sco])e of the work, there is no reason why those of the day before should be left out in the cold. Accepting, however, both his extension and his limitation of the subject, we think that Sir Harry Johnston has succeeded in producing a very readable and attractive book, and one which may, in its general scoi)e and style, well form a model which more scientific zoologists would do well to copy. An absence of details is noticeable, and the relations of the few surviving British mammals to their relatives in other lands and to their extinct predecessors are sketched in a manner which cannot fail to interest. Indeed, the work is much more than is indicated by its title, since it treats largely of mammals in general. While commending the general style of the work, we must at the same time warn our readers that h must by no means be accepted as an exhaustive account of Briti.sh mammals, or one that is free from errors. For instance, while in the case of one species of the mouse tribe the local sub-species are given, in some of the others they are omitted. This, of course, is inexcusable. It woukl'have been perfectly legitimate to ignore bub-species i» toto, but to notice them in one case and omit them in others, can only be taken to mean either that the author is inexcusaljly careless, or that he knows his subject imperfectly. We might also refer to certain inconsistencies in regard to nomenclature, did space permit. To justify the assertion that the book is by no means free from serious errors, we may cite the statement on p. 20'J to the effect that ancestral rhinoceroses had four toes on each foot, and also the one on p. o7u that Jasu.ujy, 1904.] KNOWLEDGE 15 ^facaqiie monkevs are the only ropresentativos of their kind whioh in Asia inhabit districts with a climate ;is cold as that of England. The author's theories, too. must bo accepted with reserve — notably the suggestion (p. iiiil!) that American monkeys originated in Africa, seeing that not a vestige of the remains of one of these creatures has hitherto been discovered in that continent. A striking feature of the volume is formed bj' the coloured plates 'reproduced from the author's own sketches), which differ markedly in style from the illustrations commordy seen in zoological works. As to the merits of these sketches, we must, however, leave our artist friends to decide. 'The Moon: CoNsmEUEn as a Planet, a World, and a Satellite." By James Nasniyth, c.e., and James Carpenter, F.R.A.s. J[urray.) — The moon is a dead and unch.-inging world. As it was when tialileo looked upon it through tlie first telescope, so it was when Nasmyth and Carjienter brought out the third edition of the " Moon " in 187.'), and so it is to-day, when the publishers have issued a verbatim reprint of the same book. Perhaps it is because of its unchangeableness that so little progress in our knowledge of the moon seems to have been attained in the last quarter of a century or more, for the joint authors raise the same problems, and give the .same doubtful answers to the same questions that we do to-day. The book is in fact up-to-date for all intents and purposes. In illustration alone do we seem to have made a notable selinograpliical .advance. When Xasmyth and Carpenter wrote, photograplij' was a very unskilful assistant to the study of the moon, and their lunar drawings were (as they still are to-day) incomparably the finest representations made by hand of the moon's surface. The re-publication of the book in a more convenient size, and at tlie greatly reduced price of 5s., will meet with wide acceptance. The paper and print are both pleasing. We notice one mis- print on p. 79, where ^^r, is written for juW- '•MiNTTE Marvels of Nattri:." By John .J. Ward. (London: Isbister & Co.) — The aim of the author of this book is to exhibit in a popular manner some of the striking and interesting subjects which are revealed by the microscope, and to describe them in such a way as will attract the unscientific reader. To this end the book is freely and admirably illustrated by 184 reproductions, principally photo-micrographs, and they cover a very large range of subjects. Bearing in mind the jmrpose of the book, the critical judgment is largely suspended. Errors there are, but not such as substantially weaken its object. A microscopist is apt to become a little impatient when he sees a group of specimens which includes Anchors and plates from the skin of the Synapta included in the title of '" Diatoms.'' .Several other little blemishes occur, and the description of the manner of the use of the pulvUli of the fly's foot — for so long a subject of controversy — might with advantage be revised. .Still the book, placed in the hands of one who is unacquainted with microscopical subjects, is likely to create interest and lead to a desire for further information and investigation ; if it succeed in this, its purpose will be achieved. " BciiDisT India." By Prof. T. W. Rhys Davids. Pp. xv. + 'i?>2. (Fisher Un win.) Illustrated. l>s. — The rise of Buddism in India has provided Prof. Rhys Davids with a theme for a scholarly work. If India were subject to a nation like Germany, exploration of the rich field of historical research, of which this book gives us an inspiring sketch, would be made a subject of national concern ; but here it is not considered necessary to make inquiries into the ethnology or archajology of the races which constitute our Empire, and it is left to scholars like Prof. Davids to rescue such knowledge from oblivion. It is usual to adopt the Brahmin idea of ancient India, with its doubtful theories of castes and history, but inscriptions and other records have provided material for the conatiuction of a connected account of India without accepting the Brahmin point of view as the final one, and equally true five centuries before Christ and five centuries after. Prof. Davids describes from the avail- able evidence the kings, clans and nations, social and economic conditions in India in the sixth and seventh centuries i;.('. 'I'ht^ Buddist influence was most early felt in tlie north of Indi;i, and the picture of village life at that time shows that the " ma.ss of the people, the villagers, occupied a social grade quite different from, and far above, our village folk." The claim of the priests to social superiority was not recognized and the caste system as it is now understood was unknown. There were different families or clans, but the caste system, in the exact use of the torni, did not come into existence until long afterward. As to literat\n'o, the oldest reforei\c'c to writing is in a tract dating approximately to 4.')0 li.c. The priests appear to have been indill'erent and even opposed to the use of writing. " All the present available evidence," remarks Prof. Davids, "tends to show that tlie Indian alphabet is not Aryan at all ; that it was introduceil into India by Dravidian merchants ; and that it was not, in spite of their invaluable services in other respects to Indian literature, to the priests, whose self-interests were opjioscd to such ili.scoveiics, but to trader.s, and to loss prejudiced literary circles, that India owes the invention of those imjirovements in the mechanical aids to writing that enabled tlie long previously existent knowledge of letters to bo applied at last to the production and preservation of books." liimitations of space prevent us from mentioning more of the interesting points with which this volume is filled. I'luddism slowly but continually lost its place as a national faith and now there is .scarcely a Buddist left in the land where Buddism arose, (j'hanges in the faith itself, changes in the intellectual standard of the people, and the influence of foreign tribes which invaded India from the north-west, are suggested as causes for the decline and fall of Buddism in India. Prof. David's story of the rise of the faith, and the conditions of the people who professed it in India, is a contribution worthy of his great learning, and of great interest to every student of history. " OnSEKVATioNS OF A Natura[.isi' r^^ tiik Pacikio hktwhkm 18'Ji; AND i.H'J[)." By H. B. Gnppy, M.r.., f.r.s.e. Volume I. " VanuaLevu, Fiji." 'Pp. xx., .".'.Vi. (Macmillan.) l.5s.— This book is the work of one who does not shriidc from detail; and it has more in common with the elaborate memoir of a State survey than with the ordinary record of a traveller. In a country where the annual rainfall varies from. 1(K) to 2.'i0 inches, whore the interior tends to become wilder and less populous, and where dense forest prevents the mapping of geological boundaries, Mr. Ouppy has made elaborate notes of every rock-exposure that ho could visit. He includes the tine volcanic necks that rise sheer above the agglomerate layers and the marine sediments of the plateaux ; and he shows how the general volcanic action took jjlace in Cainozoic times beneath the sea. Inclining, evidently, to a theory of U[ihcaval, rather than to the difficult hypothe'sis of a recession of the level of the sea, he yet does not absolutely commit himself on this important subject. His unwillingness to generalise makes the book rather serious for the reader. The types of lava met with are classified with what seems an excess of detail, .secdng that nothing new is revealed concerning their behaviour or occurrence as rock-masses. The felspar crystals are carefully measured under the microscope, and the presence or absence of fluidal structure in the ground-mass is noted in each case. In dealing with the felspars which are commonly called " laths " by workers with the microscope, Mr. Ouppy prefers the fourteenth century term " lathes." His phrase " lamellar extinction," moreover, does not strike us .as a very happy one. Still less do we like the '' formulio " devised for the comparison of one rock with another. This is all very well for the note-book of one who is correlating a large series, but such a system seems hardly necessary in the published work This cumulative evidence as to the interstratification of marine sediments and volcanic ilfbr/s throughout Vanua Levu is of wide interest and imiiortance; tho minimum emergence (p. 31.5) that has made the present island is valued at 2500 feet. The history is one of a struggle between the forces of elevation and the constant planing action of the sea. A rise of another tJDO feet would connect 'V'anua Levu with its sister island, Viti Levu, on the south-west. The plateau that forms a floor for the later accumulations is regarded as due to spreading lava flows (p. 371-5). Similar plateaux, cora|)leted in Oligocene tunes, and now buried in marine sediments, would doubtless be revealed by local elevation in the region between Ireland and the FariJo Isles. The whole book is admirably produced, but wo cannot help thinking that it would have gained by considerable excisions, and by the substitution of a classified list of the localities from which specimens hail been collected, in place of the detailed descriptions of so many individual instances. 16 KNOWLEDGE. [January, 1904. "Among the Night People." By Clara D. Pierson. Pp. xii. + 221. (John Murray.) .5s. — Tt may be doubted whether any useful scientific purjiose is served by regarding the lower animals as reasoning creatures possessed of sentiments like those of human beings and a vocabulary superior to that of many people. In the dainty book before us not only do raccoons, rats, foxes, weasels and other " varmin " carry on animated conversations, but also mosquitoes, caterpillars, fire- flies and molhs. Children have no difficulty in imagining a doll or rocking horse to be endowed with life, so that the stories in this book will appeal to them vividly. Regarded as food for imagination, comparable with fairy tales and classical legends, the stories are very good and will please many young people. As for natural history, well, there is a vein of it among the whimsicalities described and the fine feelings pourtrayed, but the pity of it is that children will be unable to discriminate between what is real and what imaginary. "Mathematical CEYSTALLOGRAPiiy and the Theory of Grouts of Movements." By Harold Hilton, m.a. Pp. xii. -f- 'I6'2. (Clarendon Press.) 14s. net. — Earnest students of crystallography will be grateful to Mr. Hilton for his treatment of a branch of the subject usually neglected in English text- books. The geometrical theory of crystal structure is a fascinaling field of study which the mathematician and the crystallographer can explore to the mutual advantage of both. From considerations of symmetry and finite groups it is shown that there are onl}- thirt}'-two groups of movements consistent with the law of rational indices, and therefore applicable to crystallograph}'. The argument thus develops the thirty-two crystal classes given in text-books on the subject. Three chapters are devoted to the description of the more important properties observed in crystals, and with chapters, among others, on the points already mentioned, form the first part of the book. The second part is devoted to theories suggested to account for these properties, the methods and notation used by Schcinflies in his "Krystallsysteme und Krystallstructur'' being closely followed. The work of other investigators of the geometrical theory of crystal structure, which may now be regarded as fairly complete, is included, so that the volume is of importance both for reference and as a supplement to modern text-books. BOOKS RECEIVED Direction of Bair in Animals and Men. By Walter Kidd, M D., r.z.s. (A. & C. Black.) lUustratoa. 5s.net." The Cosmos and the Creeds. By Capt. AT. U=borne Moore. (Watts) 4s.net. The Sir/ns of Life. By Augustus D. Waller, M.D , F.R s. (Murrav.) Illustrated. 7s. Bd. net. Essai/s and Addns.^es, 1900—li)0:i. By the Et. Hon. Loid Avcbury, P.c. (Macmillan.) Ts. €d. net. JEton Nature Sliid;/ and Observational Lessons. By Mattliew Davenport Hill, M.A., r.z.s, and Wilfred Mark Webb, P L.s. (Duckworth & Co.) Illustrated, .'is. Gd. net. /School Oeometri/. 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December. 2s. 6d. net. Eoss Limited Abridge Catalogue, 1903. Newton cf' Co. Supplementary List of Lantern Slides, 1903-4. THE ANCESTRY OF THE HORSE. By E. Ly'dekkee. If an e.xpert mechanical engineer, totally unacquainted with zoolo!:>-y and comparative anatomy, were shown for the first time the skeleton of a tapir, and told that it bekmged to an animal adapted to life in swamps, and were then asked if he could suggest improvements in the struc- ture of the bony framework in order that the animal might be suited for a life on the open plains, and possess a high turn of speed, there wouH be little doubt as to the nature of his answer. After examining the short limbs, with two ]3arallel bones in the second segment, and their three or four tees each, he would at once say that it is essential to lengthen all the bones of these j)ortions of the skeleton, and to reduce the width of the foot either l)y diminishing the size of all the toes except the large middle one (which would have to be proportionately increased), or by doing away with them altogether. He might fiu-ther suggest that it would be imjjortaut to lengthen the bones of the lower segments of the limbs (except, of course, the three terminal ones) to a much greater extent than tlie upper one. And if he were specially inventive he might also point out that a much greater stride and far more mechanical power would be gained, if the animal could be made to stand only on the extreme tips of its toes, so that the whole of the hinder portion of the foot would be raised above the ground. Puitlier. he might also advise that it would confer strength and solidarity on the limbs if the two bones in the second segment of each were welded together, so as to form but one. If. moreover, he were told tliat the tapir is probably a short-lived animal, which feeds on soft marsh vegetation, and tliat it was essential to olitain an animal whose span of life should be from fifteen to twenty years, and whose food should consist of dry grasses and grain, he would naturally look at the molar teeth of the tapir. Tliese he Would find to have low crowns surmounted merely by a few simple ridges ; and if the skeleton belonged to an old individual, he would not be long in discovering that some or all of them were worn nearly or quite down to the roots. Obviously his answer would be that the crowns of the teeth must be very considerably lengthened ; and, more- over, so constructed as to be more capable of resisting wear, and better adapted for grinding hard substances than are those of the tapir. After this inspection of the skeleton of the tapir, we Januarv, 1904.] KNOWLEDGE. 17 must iinajjiue our ent;ineer to be iutroduced to that of the horse. " Here we have," he would say, " the very ideal aniiuiil you want, aud I can sugjjest absolutely no uieehanioal improvement iu its framework, save that I fail to re;dise the use of the two small splints of bone attached to the sides of the upper part of the eanuon-bone in eaeh limb."' Here, indeed, we have in a nutshell the essential differ- ence between the horse (and its near relatives the zebras and asses) and its earlv ancestors, which. althoui;h of FiS. 1. — Skeleton of Hyracotherium, of the Lower Eocene Period in North America and Europe. (After Cope.) smaller size, were generalized creatures not far removed in their organization from the tapir. In the ancestral tvpe there is abundant room for modification and speciali- zation, whereas in the other the possibilities of improve- ment and advance appear to have Ijeen exhausted, aud the animal is (with the aforesaid exception) practically perfect for its own special mode of life, and is the supreme development of which its line is capable. The mode in which this perfection has been attained during the slow couree of evolution, it is my jiurpose, so far as sjsace permits, to demonstrate in the present article. The earliest mammal to which we can at present defi- nitely afiiliate the horse and its relatives is one from the lowest part of the lowest, or Eocene, division of the Tertiary period known as Phenacodus. This was a short-legged creature not larger than a fox, with a relatively small head, long tad, and five toes to each foot. On these five- toed feet the creature probably walked much in the same way as the modern tapir, that is to say that although the wrist and ankle joints were raised well above the ground, all the three bones of each toe were applied to the same, and the sole was provided with cushion-like pads. Very important is the circumstance tliat in each foot the middle toe was symmetrical in itself, and decidedly larger than those on either side. The toes — and more especially those in the fore-foot — were distinctly expanded at the extremity, and during life were encased in horny sheaths which were probably more like hoofs than claws. Not less important is it to notice that in the skull the socket of the eye was not closed behind by a bar of bone, and was thus con- tinuous with the great hollow on the sides of the temples for the reception of the muscles which worked the jaw. As regards the teeth, it must suffice to say, firstly, that they were forty-four in number, as iu so many c)f the early generalized mammals, and that although well-marked tusks, or canines, were present in both jaws, there was no distinct gap at the commencement of the grinding, or cheek-series. Secondly, these cheek-teeth had very short crowns, surmounted by four simple conical elevations, or cusps, between which were a couple of smaller cusps. Into other details of the structure of this primitive creature it would be out of place to enter here. As to its coloration in life, no one has, I believe, hitherto ventured to make even a suggestion. When, how<'ver, we advance one step further iu the scale, and come to the Hiirdrotlifriuiu of the Lonoially in the lower jaw, was ijiiite riulimeutarv, and often shed in old a>;;e. There is, like- wise, another point in connection with the cheek-teeth of this aud the last Ljenus. lu Aiichitlifriitin imd the earlier forms, the <'heek-teetli. with their ridt^ed crown- surface, were adapted solelv for an uii-and-down champing,' move- ment, such as occurs in the jaws of the pifjs. On the other hand, the Hat millstone-like surface formed l)v the cheek-teeth of the hippariou and the modern horse permits of a horizontal grinding movement, much better adapted to the comminution of hard substances. These three-toed horses were further peculiar for the presence of a depression on the sides of the face for a gland comparable to the tear-gland of deer and many antelopes ; traces of the depression being visible in certain modern horse-skulls, aud also existing in a much more marked degree iu the extinct Siwalik horse (Eqiivf! sivalfusis) of India. The presence of these face-glands indicates that the hipparious prolxibly frequented country covered with tall grass or bush, in which the scent given out liy their secretion would aid the members of a troop in tracing the whereabouts of their fellows. On the other hand, in the open grassy plains (which by the way are probably a comparatively recent feature in the history of the earth) such aids are quite unnecessary, and the glands have accordingly been lost in the modern horse and its relatives. In height the hipparion stood about 4 feet 6 inches (13'i hands) at the shoulder. In coloration it was probably strij^ed after the fashion of the zebras. During the Pliocene period horses obtained for the first time an entry from the North into South America, where they developed into two generic types known as Hippidiiim and Onohlppidiiim. Having large face- glands, and comparatively short and simple cheek-teeth, these South American horses were specially distinguished by the great length of the slit on each side of the face below the nose-bones. Evidently, therefore, they were off the line of the modern horse, although it is believed that the second, at any rate, were single-toed. If, as some believe, indigenous horses existed iu South America at the time of its discovery, they must have been Onohippidiums. In the Lower Pliocene of India aud the Upper Pliocene of Europe aud Asia appear for the first time true horses of the genus Equus, characterized Ijy the total disappear- ance of external lateral digits, the sole relics of which are the splint-bones at the upper ends of the cannon-bones, alluded to above as being the only superfluous aud appa- rently useless structures noticeable in the skeleton of the horse. They seem, in fact, to be structures of which these animals have been unable to rid themselves ; and are actually injurious, being tbe cause of the disease known as splint. To the evolutionist they are, however, inde- scribably valuable, as affording incontrovertible evidence of the descent of the horse from the three-toed forms. In all the one-toed horses the pattern on the crowns of the upper cheek-teeth (Fig. 8) differs in a certain detail from that of the hipparions. The Pliocene horses approximate, however, in this respect more to the latter than in the case with their modern descendants, as they also do in the somewhat shorter crowns of the cheek-teeth. Moreover, the occur- rence of a first upper piremolar (the " wolf-tooth " of the vets.) was less uncommon in these Pliocene species than in the horses of to-day ; and they occasionally developeii the corresponding lower tooth, which is quite unknown in the latter. Whether, however, the mares of the Pliocene horses resembled those of the present day in the absence of the canines, 1 am unable to say. Passing on from certainty to conjecture, it is probable that at least some of these Pliocene horses were striped like the zebras. S]iecies, however, such as the immediate ancestors of the modern /?'/»».< rnhdllus — the domesticated horse of the jiresent day and its wild or semi-wild relatives th(( dun-coloured ])onies of Mongolia — th(> wild asses, and, in a less degree, the extinct South African quagga, which took to a life iu the open plains in countries where there is strong sunlight, found this type of coloration uusuited to their needs and accordingly assumed a more or less uniformly coloured coat, as being best adapted for protective rescmldance in such situations. The above- mentioned tendency to revert to stripes, es|H'cially iu tlit^ case of hybrids, affords, however, proof ()f their zebra-like ancestry. As early as the Prehistoric ]jeriod, as we infer from the rude drawings of the animal by its first masters, the European horse was uniformly colourcKl — probably dun with dark mane, tail, and legs. It was a small heavy- headed brute, with n)ugh scrubby mane and tail, and no trace in the skull of the depressiim tor the face-gland. From this stock are descended the cart-horses and the ordinary breeds of Western Europe. The blood-horse, or thorough- bred, on the other hand, is a later imi)i)rtation into Europe either from Arabia, by way of Greece and Italy, or, as some think, from North Africa, the homo of the barb. It has been supposed that these Eastern horses are the descendants of an earlier domestication of the same stock. I have, however, recently shown the existence in an Indian domesticate.l horse-skull, as well as iu the skull of the race-horse " Ben d'Or," of a distinct trace of the depression for a face-gland, and the suggestion consequently presents itself that the Eastern horses (inclusive of thoroughbreds) are derived fnim E'lip, of all the staining and dehydrating re-agents, and of the mounting medium, by the method of irrigation. MlcEO.scopiCAi- M.\TF,RIAL. — By the kindness of Mr. C. S. Ponlter, of Wallington, I am able to ofl'er to the microscopical readers of KnowleiiOE some leaves of /Miit^iu snihrii, showing stellate hairs, and of KIa(afinu< ediilin, showing peculiar scales. Those who desire to avail themselves of this material, should send me a stamped addressed envelope, together with the coupon appearing in the advertisement columns of this journal. NOTKS AND QUERIES. C. Judnoii. — There is no reason why the numerical aperture of suhstage condensers as well as of objectives should not he determined by the method described in Knowliuiue of November last. It should be borne in minv : — Disappearance. Beappearance. aj 1 i s c 6 4« a Is < M a . Is si 5» h •< m g o g h. m. 1 ° o b. m. o o d. h Jan. I in Tanri I o-2 6 8 P.M. 129 170 6 49 P.M. 214 2,V! 13 21 „ 3 26 Gemiuorum .VI 1 34 A.M. 1 66 40 , 2 .32 A.M. «« 274 15 4 ., 5 o LeoDis a-8 1013 P.M. 129 167 11 9 p.m. 2.i9 ?,95 18 1 ■ > 26 D.M + 12°436 ,=«■!» 7 19 P.M. , 2.i 16 8 11 P.M. :iO!» ifSl 9 4 >. 28 B.A.C. 15215 5-8 6 16 P.M. '. 7U 99 1 7 28 P.M. 271 W6 11 3 „ 30 A Geluinoram 36 3 6 A.M. 106 1 66 4 3 am. 275 234 12 11 The Planets. — Mercury is an evening star in Capri- cornus. He is at greatest easterly elongation on the 1st, being 19''30 E., and sets for a few days near this time about H hours after the sun. On account of his great southerly dechnation, however, he is not favourably situated for easy observation. He is again in inferior conjunction with the sun on the 17th. Venus is a morning star, and rises on the 1st at 4.22 A.M., and on the 31st at 5.28 a.m. Her brilliance, is, however, diminishing on account of increasing distance from the earth and greater southerly declination. Mars is low down in the south-west at sun-set, but is very feeble and badly placed for observation. Jupiter is on the meridian about sunset near the beginning of the month, whilst near the end of the month he sets about 9 p.m. The diameter of the planet is diminishing on account of his increasing distance from the earth, the polar and equatorial diameters being 34"'3 and 3(5"'7. The configurations of the satellites, as seen in an inverting telescope, and observing at 7 p.m., are as follow : — Bay. West. East. Day. West. East. 1 3 2 O 1 4 17 3 O 1 2 4 2 3 1 O 2 4 18 2 O 3 4 • 3 1 O 2 4 • 19 2 10 3 4 4 2 O 1 4 3 20 O 1 2 3 4 5 J O 4 3 21 1 3 O 2 4 6 4 O = 2 22 3 2 O 4 1 7 4 3 1 O 2 23 3 4 1 2 O 8 4 3 2 O 1 24 4 3 O 1 2 9 4 3 1 O 2 25 4 2 1 O 3 10 4 ® 2 • 26 4 2 0 3 11 4 2 O 3 • 27 4 O 1 2 3 12 4 2 1 O 3 28 4 1 ® 2 13 4 O 1 3 2 29 4 3 2 O 1 14 I O I 30 3^20 15 3 2 O 1 4 31 3 O J 2 16 3 1 O 4 • Tlie circle (O) represents Jupiter ; 0 signifies that tlie 9at«llite is on the disc ; • signifies that the satellite is behind the disc, or in the shadow. The numbers are the numbers of the satellites. Saturn and Uranus are lost in the sun's rays and cannot be observed. Neptune comes to the meridian about 10.30 p.m., near the middle of the month ; being close to ft Greminorum, he can readilv be found by reference to that star, their respective positions on the 16th being : — Right Ascension. N. Declination. Neptune ... 6b. 17m. 16s. ... 22° 18'^ 31" ju. Geminonim .. 6h. 17m. lis. ... 22^ 33' 37" The planet therefore will be 15' directly south of the n> 26^ 24" ^ o" 1 b" 2 -^-,-^ ■ f ^! ^[ •• '. 1 — t. \ • ■ .• i. • ^r^ k22 « . . • M 1 . ■ •• . • ^^l • . • . .- -6- C4." C l"" -■" .-^^l Chart showing path of Xeptune in 1904. star, and will appear in the same field of view with a not too high power eyepiece. The above chart shows the planet's path during the year 1904. .1a.m-.uiv, 1901.] KNOWLEDGE. 23 Metror Showers :-^ Date. Badiout. Name. Clmraoteristiis. R.A. Deo. Jan. 2-3 1" o 230 21)5 o + 53 + 53 Qviadrantids K Cygnids Swift ; long patlis Slow ; bright South West East North The Stars. — The positions of the principal constellations near the middle of the month at 9 p.m. are ;is follow : — Zenith . Perseus, Auriga (CapeUa). Pleiades, Taurus, Orion, witli Aries anle stiir $, is the finest of all nebulsB, and is so bright that it can lie discerned with the naked eye ; with a 'S or 4-iuch telescope, it is best observed when low powers are em- ployed. Crab Nebula (M 1), in Taurus, situated about lj° north-west of K Tauri in R.A. 5h. 29m., Dec. 21° 58' N. Clusters. — il 37, situated in Auriga, is one of the finest clusters, and verv compact ; its position is R.A. 5h. 46m., Dec. 32^ 32' N. " Double Stars. — j3 Orionis (Rigelj, mags. 1 and 9, separation 9". On account of the brightness of the prin- cipal star, this double is a fair test for a good object- glass of about 3.inch aperture. S Orionis, mags. 2 and 7, se]iaration 53" ; easy double. K Orionis, triple, mags. 3, 6, and 10, separation 2"5 and 50" ; rather difficult in a 3-inch telescope. A Orionis, mags. 4 and 6, sepai-ation 4"'5 ; pretty double. o" Orionis, triple, mags. 4, 8 and 7, separation 12"'5 and 42". There are several other small stars near, and the Diagram of c Orionis. detection of the fainter ones is looked upon as a good test of the light-gathering power of the telescope. With a 3-inch, one can see up to number 7, though 4 is very difficult. dbfss (Column. By C. D. LococK, h.a. Communications for this column should be addressed to C. D. IjOcook, Knowi.kduk Office, 326, High Holborn, and be posted by the 10th of each month. So l\itions of Dec'euiber Problems. No. 1 (W. Geary). K,;y-moi!fi.—\. B to B7. . K to B5, 2. Q to KBs(i, ch . ICt ( I5s(|) moves, 2. B x Kt. . P to K6, 2. Q to Q3cli. . . ]' to Q5, 2. Q to Ksq, ch. . . P to Kt5, 2. Q to (j4ch. . . Kt (Q3) moves, 2. Q to Q3 mate. If 1. 1. No. 2 (C. D. Locock). Key-move. — ]. Kt to K8. . K to B4, 2. Q to R7. . KtoK6,orKt6, 2. QxPch. Solutions received from "Alpha," 4, 4; W. Nash, 4, 4; G. A. Forde (Major), 4, 4; "Looker-on," 4,3; G. VV. Middleton, 4, 4; " Quidam," 4, 4; J. W. Dixon, 4, 4; C. Johnston, 4, 4 ; H. S. Brandreth, 4, 0 ; H. F. Culmer, 4, 4 ; T. Dale, 4, 4 ; J. Jones (Salford), 4, 4. "Looker-on." — After 1. Kt to B8 (which you give as an alternative to 1. Kt to R8), the defence K to B4 appears to be good ; for if then 2. Q to R7, K x P. Many condolences on the loss of a point at the last and critical moment. H. S. Brandreth.— Aiter 1. B to Q5, K to B4 ; 2. Q to Bsq., K to Kt3. There is no mate. C. Johnston. — Many congratulations. Please send your full address. Result op Solution Tourney, 1903. Winner of the Knowledge Challenge Trophy. — C. Johnston, 83. Winner of Second Prize (15s.). — ^" Looker-ou " (G. J. Slater, Bolton), 82. Winner of Third Prize (Knowledge for 12 months). —J. W. Dixon, 81. These are closely followed by W. Nash and " Quidam," 80. Other scores worthy of mention being : G. W. Middleton, 73; "Alpha," 68; H. F. Cuhuer, 64; G. A. Forde (Major), 62 ; and T. Dale, 58. Mr, Dale did not compete iluring tlio first three months, or he would evidently have taken a much higher place. The above award will remain open for one month. The sct)res of the first five show the closeness of the competition, the ri'sult of which was in doubt till tlie last. Last year Mr. " W. Jay " came out with a clear lead of four points. In the present competition the liolder of the trophy retired early, and Mr. C. Johnston, who tied for fourth place last year — 20 points behind Mr. .lay — scores a well-.rv- Ca.rrying Machine. Many of our readers have tloubtless been keenly inter- ested in some of the experiments now being conducted in luigland, and especially in .Vmerica, with Hying machines. Hitherto but little success has attendeil the efforts of inventors, and though on a few occasions a model has shown its power of progressing through the air, yet all attempts to raise a man from the ground have proved abortive. Various vague and sensational accounts have appeared in the Press durmg the last few weeks of a most impor- tant experiment made in .America by the brothers Wright. We are now able to give an authentic account, kindly sent by Mr. Orville Wright himself, of what actually occurred. He states that he had not intended at present making any public statement with regard to the trials, but that "newspaper men " gave out "a fictitious story incorrect in almost every detail," so that the inventors feel impelled to make some corrections. The real facts were as follows : - • On the morning of December 17, between the hours of 10.30 o'clock and noon, four flights were made, two by Orville Wright and two by Wilbur Wright. The starts were all made from a point on the levels and about 200 feet west of our camp, which is located a quarter of a mile north of the Kill Devil sand hill, in Dare County, North Carolina. The wind at the time of the flights had a velocity of 27 miles an hour at 10 o'clock, and 24 miles an hour at noon, as recorded by the anemometer at the Kitty Hawk weather bureau station. This anemometer is 30 feet from the ground. Our own measurements, made with a hand anemometer at a height of four feet from the ground, showed a velocity of about 22 miles w-hen the first flight was made, and 2oi miles at the time of the last one. The flights were directly against the wind. Each time the machine started from the level ground by its own power alone with no assistance from gravity, or any other sources whatever. After a rim of about 40 feet along a mono-rail track, which held the machine eight inches from the ground, it rose from the track and under the direction of the operator climbed upward on an inclined course till a height of eight or ten feet from the groimd was reached, after which the course was kept as near horizontal as the wind gusts and the limited skill of the operator would permit. Into the teeth of a December gale the " Flyer" made its way forward with a speed of ten miles an hour over the ground and 30 to 35 miles an hour through the air. It had previously been decided that for reasons of personal safety these first trials should be made as close to the ground as possible. The height chosen was scarcely sufficient for mancEuvring in so gusty a wind and with no previous acquaintance with the conduct of the machine and its controlling mechanisms. Consequently the first flight was short. The succeeding flights rapidly increased in length, and at the fourth trial a flight of 59 seconds was made, in which time the machine flew a little more than a half mile through the air, and a distance of 852 feet over the ground. The landing was due to a slight error of judgment on the part of the operator. v\fter passing over a little hummock of sand, in attempting to bring the machine down to the desired height, the operator turned the rudder too far, and the machine turned downward more quickly than had been expected. The reverse KNOWLEDGE & SCIENTIFIC NEWS. [Feb., 1904. movement of the rudder was a fi action of a second too late to prevent the machine from touching the ground and thus ending the flight. The wiiole occurrence occupied httle, if any more, than one second of time. ( )nly those who are acquainted with practical aeronau- tics can appreciate the difficulties of attempting the first trials of a flying machine in a 25-mile gale. As winter was already well set in, we should have postponed our trials to a more fa\ourable season, but for the fact that we were determined, before returning home, to know whether the machine possessed sufficient power to fly, sufficient strength to withstand the shock of landings, and sufficient capacity of control to make flij^ht safe in bois- terous winds, as well as in calm air. When these points had been definitely established, we at once packed our A Wright Machine— A side view. goods and returned home, knowing that the age of the flying machine had come at last. From the beginning we have employed entirely new principles of control ; and as all the e.xperiments have been conducted at our owm e.xpense, without assistance from any individual or institution, we do not feel ready at present to give out any pictures or detailed description of the machine. It may be mentioned that the Messrs. Wright have for some years been conducting a series of experiments with " gliding machines," that is to say aeroplanes without any engine or propeller. With them the operator starts from the top of a hill and glides down through the air to the bottom, thus having to balance and control the machine. We gi\ e here an illustration of one of the gliders, which is probably very similar to the machine recently tried, but the latter apparently had a motor and propeller added. ^.^^^^^ Electrical Novelties- Giant and Miniature S\ins. By J. E. Gore, F.R.A.S. Messrs. F. Darton and Co.'s list of electrical novelties, just published, is remarkable for the cheapness of most of the articles which this firm supplies. The novelties include house telephones, hand gears and hand-geared dynamos for demonstration purposes, and their vvell-Unovvn small dynamos for working with small oilengines. This firm also has'a num- l)er of attractive small electric light sets and economical motors for fans and light electric power work. It was at one time thought a probable hypothesis that the stars were in general of approximately equal size and brightness, and that their difference in brilliancy de- pended chiefly on their relative distance from the earth. On this apparently plausible hypothesis, we should have — taking the accepted " light ratio" of 2-512 — an average star of the first magnitude equal in brightness to 100 stars of tfie sixth magnitude. As light varies inversely as the square of the distance, this would imply that a star of the sixth magnitude — that is one just steadily visible to average eyesight in a clear and moonless sky — would be ten times farther from the earth than a star of the first magnitude. For the same reason, a star of the eleventh magnitude would be at ten times the distance of a star of the sixth magnitude, and therefore 100 times the distance of one of the first magnitude. .'\n eleventh magnitude star is about the faintest just steadily visible with a telescope of 3 inches aperture. For stars of the sixteenth magni- tude, or about the faintest visible in a 25-inch refractor, the distance would be — on the above hypothesis — 1000 times the distance of a first magnitude star. Although this hypothesis was plausible enough at first sight, there never was any real evidence to show that the stars are 01 equal size and brightness, and modern re- searches ha\e proved that they differ greatly in absolute size, and also in intrinsic brilliancy of surface. Measures of distance have shown conclusively that several small stars are considerably nearer to us than some bright stars, such as .^returns, \'ega, Capella, Rigel, and Canopus. These brilliant orbs must therefore be vastly larger than the faint stars which show a larger parallax. On the other hand, we have reason to believe that many stars are much smaller than our Sun. A consideration of some of these giant and miniature suns, as they may be termed, may prove of interest to the general reader. We will first consider some of the "giant" suns. The well-known reddish star Aldebaran (a Tauri) in the Hyades maybe taken as a standard star of the first mag- nitude. A small parallax of o'loy of a second of arc was recently found for it at Yale College Observatory (U.S.A.). This makes its distance from the earth about seven times that of a Centauri (of which the parallax is o"-75). Now, as Aldebaran has the same spectrum (K 5 M, Pickering) as the fainter component of a Centauri (magnitude i'75i, the two stars may be considered as fairly comparable in intrinsic brightness. From the above data I find that Aldebaran is about 92 times brighter than the companion of a Centauri and its mass about S82 times greater. But the components of a Centauri are of equal mass, and each equal in mass to our Sun. Hence Aldebaran has prob- ably a mass 882 times greater than that of the Sun ! The red southern star Antares (a Scorpii) is of magnitude I -22, according to the most recent measures at Harvard Observatory, and its parallax, according to Sir David Gill, is about o"-o2i. Comparing with Aldebaran, we have the latter 1159 times brighter. But Antares is at five times Feb., 1904.] KNOWLEDGE i^- SCIENTIFIC NEWS. the distance of Aldebaran. Hence the real brightness of Antares will be -^ , or 21-5 times greater than that of 1-159 Aldebaran. The surface of Antares would therefore be 21-5 multiplied by 92, or 197S times the surface of the companion of a Centauri, and its mass about erlin may boast of having quite a unicjue means of communication. The system has, by the way, neen in operation for some time with great industrial concerns such as the bierlin Aligemeine l'"leklricitats desellschaft and the Siemens and Halskc Company for communica- tion between their \-arious business departments. In addition to the type-printing telegraph used in con- nection with the teletyping service described in another note, the Siemens and 1 lalske Company have just brought out another kind of printing telegraph, intended for rapid service. The apparatus is analogous to the so-called automatical telegraph, where an apparatus similar to a typewriter pierces for each letter to lie telegraphed cer- tain holes in a continuous paper ribbon. The latter, on being drawn along through the rotating telegraphic sender, will throw automatically corresponding currents into the line. As the Siemens apparatus is capable of telegraphing 2,000 letters per minute, the telegrams trans- mitted by a large number of officials will be sent on the same wire. Two holes are pierced for each letter, the letter itself being printed immediately above in plain ordinary printing characters. The perforating may even be effected by the public itself. A disc, where the \'arious letters are cut out as in a pattern, rotates at a speed of 2,000 revolutions per minute, between a spark gap and a continuous ribbon of photographic paper. Whenever a spark passes in the gap, a silhouette of tiie letter happen- ing to be in front of the gap will be projected on the paper ribbon, which on running through sponges impregnated with developing and fixing liquids, will complete the photographic process. 20 KNOWLEDGE & SCIENTIFIC NEWS. [Feb., 1904. The Face of the Sky for Febrviary. I>y \V. Shacki.eton, F.R.A.S. The Sun. — On the ist the sun rises at 7.43, and sets at 4.45 : on the 29th he rises at 6.50, and sets at 5.36. The sun is after the clock, the equation of time reaching a maximum of 14 m. 25 s. on the 12th. Sun spots may frequently be observed ; of late, the solar disc has rarely been devoid of spots. For deter- mining spot positions the appended table should prove useful Date. Axis inclined to W. from N. point. Centre of disc, S of Sun's equator. I- eb 5 •- 13° 38' 6° 21' ,, 15 •• 17° 20' 6° 52' ■• 25 ■■ 20- 28' 7 10' The Moon : — Phases. H M. Feb. I .. ., 8 .. ,, i5 .. ., 24 .. 0 Full Moon ; Last Quarter • New Moon j) First Quarter 4 9 II II 33 P-m- 56 a.m. 5 a.m. 9 a.m. The Moon is in perigee and apogee at midnight on the 1st and 15th respectively. Occultations. — It will be seen from the particulars below that there is the interesting phenomenon of an occultation of the ist magnitude star Aldebaran, and, morevover, the circumstances are most favourable as the moon is near the meridian. Feb. 24 .\ldebaran ' i' ,, 29 lO Leonis 3-; D. H. 5.57 p.m. 7.15 p.m. 8 7 6.17p.m. 8.53 p.m. g. 46 p.m. 13 10 .it 6 p.m. The Planets. — Mercury is a morning star in Sagit- tarius; on the ioth,when he is at greatest westerly elon- gation, he rises i hr. 10 min. in advance of the sun. \'enus is a morning star, rising throughout the month about 5.40 a.m. ; she continues to diminish in brightness and is becoming more gibbous, about o-So of the disc being illuminated. Mars continues to be feebly visible in the south-west shortly after sunset ; throughout the month he sets about 7.30 p.m. Jupiter is rapidly getting more to the west and also diminishing in brightness; on the first he sets at 7.27 p.m., and on the 2Qth at 7.40 p.m. About the middle of the month his polar and equatorial diameters are 32"-4 and 34"-6 respectively. The configurations of the satellites as seen in an inverting telescope, and observing at 6.30 p.m., are as follows : — Day. West. ' East. Day. West. East. I 1034 16 24O13 2 2O134 17 i043« 1 0234« 18 0324 4 1O324 19 32O14 5 32O14 20 321O4 6 31O24 21 3O124 7 3O1* 22 13O24 8 1023 33 2O134 9 42C13 24 12O43 10 4023« 25 4O1S II 41O32 26 432 o« 12 432 0 1 27 4321O 13 4321 0 28 43O5 14 43O12 29 413O2 15 4i02« The circle (O) represents Jupiter ; G signifies that the satellite is on the disc : 9 signifies that the satellite is behind the disc, or in the shadow. The numbers are the numbers of the satellites. Saturn is in conjunction with the sun on the ist, and therefore unobservable. Uranus rises only a short time before sunrise; this, together with his extreme southerly declination, makes him most unsuitable for observation. Neptune souths at g.30 p.m. on the ist, and at 7.30 p.m. on the 29th. He is about half a degree S.E. of M Geminorum and his path is shown in the chart given in the January number. Meteor Showers : — D'BJram Illustrating Occultation ol Aldebaran. Radiant. Date. R A. Dec Near to. Characteristics. Feb. 5-10 .. 15 20 75' 236 iSl" + 41" 4- 11" + 34" 7;.'\urigae a Serpentis Cor Caroli Slow; bright. Swift ; streaks. Swift ; bright. The Stars. — The positions of the principal constella- tions near the middle of the month at 9 p.m. are as follows : — Zexith . .\uriga. South . Orion, Gemini, Procyon, Sin'ns, Cetus, Pleiades, Taurus to the S.W., Cancer and Hydra to the S.E. West . Andromeda, .\ries, Pisces, with Pegasus and Cygnus to the N.W. East . Leo, \'irgo. North . Ursa Minor, Draco, Cepheus, UrsaMajor to the right of Polaris, Feb., 1904.] KXOWI.I'IK;]' \- SCIHNTIl-lC XI'.WS. 21 Minima of Al^ol may be ohserveil 011 tlio isl at 11.52 p.m.. 4tli at 8.41 p.m., jtli at 5.30 p.m., jjiid at 1.35 a.m., 24th at 10.24 P-m-. and tlie 2jlh at 7.13 p.m. Telescopic Objects: — Clusters.- -M35, situated about 2 K.K. of >; Gemi- norum or about midway between t Tauri and < Geini- norum. Fairlycompacl, presenting a beautiful appearance of star streams when observed under favourable con- ditions. R..\. \1.^ 3™ Dec. N. 24' 21' N41, about 4" directly south of Sirius; \isible to naked eye; Messier resjistered this group as "a mass of small stars," K.A. \'I.'' 43"> Dec. S. 20^ 38' M44, the Pra-sepe in Cancer, visible to the naked eye as a nebulous patch, best seen and easily resolvable with a pair of opera or field glasses. On account of the scattered nature of the group the cluster eflPect is lost when observed through a telescope unless very low powers be employed. Situated a little to the west and about midway of the line joining <• and 5 Cancri. R..\. \'I11.'' 34" Dec. N. 20^ 20'. Double Stars. — Castor, separation 5"-8, mags. 2-7, 3-7. E.xcellent object for small telescopes. The brigiitest pair to be observed in this country ; can always be relied upon as a good show object. »■ Geminorum, separation6"-3, mags. 4, 8*5; very pretty double. i Cancri, separation i"-i, 5"-3, mags. 5-0, 5-7, 5-5; with small telescopes the wider component is readily seen. 7 Draconis, separation 6i"-j, mags. 4-6, 4-6 ; a pretty and easy double, can be separated by observing with a pair of opera glasses. The Showerof November Leonids in 1903. To THE Editors of '■ Knowledge." Gentlemen, — .'\t the end of my paper under this heading, published in the J.anuary number of " Knowledge," I referred to a second magnitude meteor seen at 15 hrs. 59 mins. on November 15, and moving in a long and slowly traversed path from a probable radiant at 113 —34 . Two of the obser\ations from which the real course was deduced were. however, somewhat imperfect and indefinite. Fortunate!)' I have since received a description of the object as seen at Greenwich at 15 hrs. 59 mins. jH sees., and I h.ive recom- puted the hei.ghts and radiant. The latter position was really in Hydra at about 147 -ii^ and the height of the meteor varied from gi to 45 miles during its extended flight of 128 miles, which it pursued at the rate of 29 miles per second. The object certainly travelled at a much slower speed than is consistent w ith a parabolic orbit. Professor Herschel has recently been comparing the re- corded paths observed on the night of November 15 by several observers, and has foimd a few interesting accordances. Two of these were of brilliant Leonids, and the real courses which I have calculated for these agree very closely with the results previously obtained by Professor Herschel, and are as follows : — Date and Greenwich mean 1 November 15 November 15 time of the observations. . ) lO hrs. 45.^ mins. 18 hrs. 7 mins. Estimated magnitudes ■■ 4-^ >l — 4 Radiant point ■ ■ 151 + 25 151 -f Zi Height at beginning 77 miles 81 miles Height at ending . . ■ • 52 .. 60 ,, length of visible path ■• 30 ,, 24 .. Velocity per second . . ■ ■ '« ,, 44 .. Observers A. S. Herschel, A S. Herschel. Slough. Slough. \V V D.. A. King, Bristol. Sheffield I W. F v.. Bristol Notwithstanding the richness of the Leonid shower in 1903, and the large number of observations, comparatively few of the same meteors appear to have been seen at two stations. Bishopston, Bristol, Yours faithfully, January 6, 1904. W. F. Denning. Comhuted by F. Siiii.i.ingto.v Sc.\li-:s, imj.m.s. Magnification of Objectives and Eyepieces I r is scarcely necessary to explain to any worker with the microscope that, whereas a simple lens gives a single magnification only, the essential principle of the compound microscope is that the image formed by the first lens or system of lenses, called the objectixe, is itself again magnified by a second lens or system of lenses known as the eyepiece, or ocular. But, simple as this is in prin- ciple, the means by which it is brought about, and the various points connected therewith, aie often not fully understood by ordinary workers, many of whom are not clear as to the exact meaning of such terms as one inch, half-inch, lVx., as applied to objectives, or to references to angular aperture as compared with numerical aper- ture, aplanatic aperture, Ac. Briefly, the principle on which olijectives are rated is as follows: We have here a Itns, or system of lenses, with which we form our first magnified image, and this image is formed at a definite distance from tlie back of the lens. According to Knghsh standards, this distance is 10 inches, which was originally adopted as being the the normal visual distance of the human eye. Then it follows that the relative size of object and image will vary directly as their respective distances from the lens, or rather from its centre. Accordingly, if the two dis- tances are i inch and 10 inches respectively, the initial magnification will be ten times, and here we have our I -inch objective. If the distances are 2 inches and 10 inches, the magnification will be five times, and the objective will be known as a 2-inch. If the distances or foci are A incli and 10 inches, the magnification will be twenty times, and the objective is A inch, whilst a i-i2th inch objective magnifies initially 120 times. On the Continent, however, the image comes to a focus about 6h inches behind the objective, this being the Continental tube-length, but the rating seems to gene- rally remain the same — the i-inch magnifying 10 times at 10 inches, the 2-inch 5 times, and so on. Thus a Continental i-inch objective used with a 6i-inch tube should only give an initial magnifica- tion at this distance of 6-5 diameters. As a matter of fact, however, objectives are nearly always overrated, sometimes absurdly so, and therefore a Continental I-inch may give an initial magnification exceeding 10, even with the short tube. Of course the tube-length of a microscope can gene- rally be varied, and the result will be in the first place a readjustment of focus and a conseijuent variation in the magnification. But the second result is that, as objec- tives are not meant to be used for uncovered objects, they have been carefully " corrected " for a certain definite thickness of cover-glass. The Royal Microscopical Society has used its powerful influence to bring makers into line throughout the world with regard to the stan- dardizing of the screw of objectives, the diameters of eye- pieces, and the size of sub-stage condensers, and it would be a great advantage if it could also standardize the thickness of cover-glass to which objectives are corrected. Perhaps this may be done some day; in the meantime 22 KNOWLEDGE & SCIENTIFIC NEWS. [Feb., 1904. each maker, whether En,L;lish or foreit^n, is a law unto himself, and the list of cover-f^lass corrections is a most torniidable one. But it follows that any variation in cover-glass thickness from that for which the objective was originally corrected necessitates a readjustment either of the lenses of the objective, by means of a " cor- rection collar," or by adjustment of the length of the microscope tube. In the latter case, of course, we have at once a variation of initial magnifying power, but the converse also applies, i.e., that an arbitrary variation of tube-length affects the corrections, and consequently the performance of the objective. We can at once see the limitations, therefore, of the ordinary suggestions as to varying the magnification by drawing out or pushing in the draw- tube of the microscope. With low powers of small angle the difference in performance is not marked, and would e\en need a trained eye to detect it, but it becomes more- and more marked with an increase of angular aperture, which generally coincides with higher powered objectives. Broadly speaking, therefore, we must use our objectives with the tube-length for which they were originally constructed. The part played by the ocular — at least by the Huy- ghenian type of ocular which is generally used and with which we need only concern oursehes here — is twofold. It consists of a field-lens and an eye-lens, with a dia- phragm between. The field-lens may really be con- sidered almost as part of the objective, for its action is to draw in the image rays and bring them to their final focus in the plane of the diaphragm just mentioned. Then the eye-lens merely magnifies this image and brings it to a focus suitable for the eye. It is important to note, therefore, that the magnification of any unadjustable ocular is always a fixed quantity, but that the magnification of an objective (perfection of image apart) will vary according to the tube-length. In spite of this, many Continental and some English makers persist in treating the two magnifications as if it were the ocular magnification which varied, thus giving rise to no little confusion. I have seen lists in which elaborate tables have been made of the combined magnifications of objec- tives and oculars used with a 6i inch tube, in which the ocular has been treated as the varying quantity, and I have seen calculations of magnifications of objectives in one and the same table in which an inch or other objec- tive is treated as magnifying 10 times and in another 7 times, at 6i inches distance, the real fact being that the oculars are not of the powers they profess to be. All this is, of course, very confusing to the beginner. Now, focuses do not represent " working distance." This merely represents the clear space between the cover- glass and the front surface of the objective, and can be measured by a carefully made wedge of wood which is inserted when the objecti\e is focussed, marked, and then measured. Nor is it necessary for us to work out with mathemati- cal accuracy the exact equivalent foci of objectives, which are made up of complicated systems of lenses. This would be a difficult matter. It will be sufficient for us to obtain the approximate equivalent focus — approximate because the centre of the system cannot be readily obtained. If we set up conjugate foci at equal distances from the centre of the lens, the object and image will l)e of the same size, and conversely if the object and the image are the same size the distances of the conjugate foci are identical. This, of course, means that object and image are both beyond the principal focus ; in fact they are at a distance just as much again as is the principal focus, i.e. they are on each side twice the distance of the principal focus from the centre of the lens. Therefore, the equivalent focus can be obtained by projecting the image of a brightly illuminated object upon a screen at such a distance that both image and object are equal, and dividing the total distance by four. Having obtained the equivalent focal length, we can easily calculate the magnification with any tube-length. It is, however, with the magnifying power that the microscopist generally needs to concern himself, and this known, the equivalent focus can be easily obtained. Perhaps the easiest method of obtaining this is that mentioned in Carpenter. A micrometer slide ruled in hundredths and thousandths of an inch, or in tenths and hundredths of a millimetre, is placed upon the stage of the microscope, and the latter inclined to the hori- zontal position. A strong light is transmitted through the microscope, and the room darkened. The micro- meter lines are then focussed sharply upon a piece of white cardboard placed five feet (60 inches) behind the front lens of the objective. The divisions on the screen are measured with an ordinary foot or millimetre rule and the result divided by 6, which gives, of course, their size at 10 inches from the objective. The value of the original stage micrometer divisions being known defi- nitely beforehand it is easy to calculate the resulting magnification. Suppose the distance between the micro- meter rulings of two i-iooo of an inch to measure ij- inches at 5 feet distance with a nominal i inch objective. Then at 10 inches distance they would measure -2083 inch, which is equivalent to an initial magnification of nearly lol times. A millimetre scale or rule can be used on the basis of 25-4 millimetres to an inch. Magnifications are always expressed in diameters, or linear measure- ments, not in areas. A considerable distance such as the above is taken so as to reduce the amount of error due to the fact that the measurements should really be taken from the principal posterior focus of the objective, which in a compound system cannot easily be found. But by measuring from the front lens as above a very small margin of error is left. It is best to take the mean of several micrometer divisions as they are not quite accurately ruled. Combined magnification of objective and eye-piece is calculated by a similar method except that there is not the same necessity for taking a longer distance, and the image of the micrometer must be accurately projected exactly 10 inches from the eye-lens of the eye-piece. This may be done either direct by means of a photo- graphic camera or otherwise, or at right angles by means of a Beale's camera lucida, to a piece of paper placed on the table, the microscope being raised if necessary to the requisite height so as to get the exact distance of loinches from the eye-lens. Short-sighted observers may therefore need to use spectacles in ordertoseethelinesonthe paper. The eye-piece magnification is readily calculated by dividing the combined magnification by the initial mag- nification of the objective, independently determined. It will be noted that the result, as calculated, gives the magnification with a lo-inch tube; any other length is easily calculated — a 7-inch tube giving an initial magni- fication of 7-ioths of the result as above obtained, and the eye-piece mat;nification remaining constant for each eye-piece. One further explanation is perhaps necessary. We have hitherto been dealing with a total magnification calculated for a visual distance of 10 inches from the eye- lens, this being the normal visual distance, but it is as well to bear in mind that in actual practice an abnormal eye will form its image nearer or further away, according to whether the eye be short or long sighted. This will, of course, proportionately affect the magnification of the eye-piece, and, in consequence, the magnification of an Feb., 1904] . KNOWLEDGE & SCIENTIFIC NEWS. object as seen through the microscope by such an observer. In making calculations connected with focal lengths the most useful formula is ' + , = ^ where p and p' p p' f denote the conjugate foci, and f the principal focus. When we know the size of the image and its magnifica- tion, and one of the two foci, such as 10 inches, we can use the proportion D :' the longer of the two foci, then, from the equation given above, i.e., I P I P^ + P" D + f and the ratio D d P' P we obtain f , or more simplj' f = p' D + d' New Spectrometer Ta.ble. Messrs. W. G. Pyc and Cd., of Cambritlge, have re- cently brought to my notice a new combination spectro- meter, the adjustments of which present quite new features, and which might, I think, be adapted to certain microscopic accessories. All motions and fittings are arranged geometrically. The base consists of a heavy iron casting on three levelling screws, having a true lathe-turned surface, with two annular V-groo\es in it, one near the outer edge, the other a few inches from the centre. The telescope and collimator are provided with tables or carriages consisting of two pieces each, the lower part having two steel balls and one levelling screw for the feet. The balls work in the larger of the two annular grooves mentioned above, and tiie levelling screw on the plane surface a few inches from the centre. The upper part consists of a cr.idle having two V sup- ports in which the telescope or collimator, as the case may be, lies evenly, being held in position by a spiral spring trap. This cradle being clamped by a thumb- screw to the lower part provides the necessary adjust- ment for getting the telescope and collimator into hori- zontal alignment. The V-fittings admit of almost any telescope and collimator being used. The two parts ol the carriage are worked up mechanically true, so that very little adjustment is needed to set them optically true after the base has been levelled, which can be done by using a spirit level in the usual manner. 'l"he carriage for the telescope is providetl with a vernier, whilst the one for the collimator has an index pointer only. The prism-plate consists of two parts, the Upper of which is capable of adjustment in the horizontal plane without alTecting the lower part, which has thrcu; spherical ended feet, two resting in the inner V-groove, the other working on the plane surface. The simplicity of the arrangement, and the easy way in which it can be worked up mechanically, combined with its steadiness and large bearing surfaces struck me favourably, and as the arrangement could easily he adapted to a reading telescope, to say nothing of adaptations to a model theo- dolite and se-xtant, circular vernier, simple dividing engine, iSrc. 1 trust its description will not seem out of place here. This instrument, when shown at the Royal Insti- tution on .\pril 3rd last, drew, I understand, considerable attention. Recent Patents. • 9.750. Natural history specimens, preserving. ^[AT^.•• soviTS, v., Liptoujvar, Hungary. Sept. 9. Beetles are preserved in a manner which keeps the joints flexible by treatment with a lliiid consisting of specified proportions of alcohol, salicylic acid, sal-ammonia, and distilled water, to which arsenic or other substances may be added. The quantity of ammonia to be added depends on the colour of the beetle to be preserved. When thorouglily impregnated, they are placed in a cool closed chamber, to dry, the joints being bent from time to time while the beetles are being dried. The liquid may also be employed in pre- serving diptera, rhynchola, &c 19,804. Hydrocyanic acid and cyanides. Wolterkck, II. C, 3, Edinburgh Mansions, Ilowick Place, Victoria Street, London Sept. 10. A gaseous mixture of, preferably, equal parts of ammonia, a carbon compound, and hydrogen is passed over a suitable catalytic agent, such as platinized pumice, strongly heated and coiitainef Iinj,;Iand, and also at some stations in the south of Ireland. In the western and northern districts .gen = crally there was a considerable excess, the amount at many of the Scotch stations being more than twice as much as the average. UDomledge & Selentifie flems A MOXllll.N' lOlRXAL C)l- SCIBNCK. Vol. I. No. 2. [NEW SEKir.s] MARCH, 1904. r Entered at LStationers' Hall. si.\i'i:nci;. Contents and Notices. See Page VH. TKe Arvcestry of the CoLmeL By R. LVDEKKER. Camels — or rather some of their immediate ancestors — have been accorded a privilege commonly said to be reserved among ourselves for the fair sex ; in other words, metaphorically speaking, they have been per- mitted to change their minds. l"or there can be little doubt that when these animals originally started on the road of getting up in the world — that is to say, on a course of specialised development — they intended to become good and typical ungulates like their distant cousins the true ruminants ; and, for a time at least, the ancestral camels appear to have had their toes encased in good service- able hoofs of horn. For some reason or other, of which we are at present quite ignorant, they appear to have considered that this plan was a mistake, and they accord- ingly struck out a line of their own, and underwent a kind of retrv-gade evolution, with the result that in their modern descendants their feet, instead of being covered with hoofs, are fitted with large spreading and elastic cushions, in which the two toes are to a great extent buried, bearing small nails on their upper surface only. The reason for this remarkable modification is not very easy to see. It is true, indeed, that the cushion-like feet of the typical camels of the Old World (from which the group derives its scientific title of Tylopoda) are admirably adapted for walking on the yielding sands of the deserts of Central Asia and Africa. But, on the other hand, such deserts are likewise the home of many hoofed ruminants, such as the North African addax antelope and the Mongolian gazella. Again, the wild representatives of the South American llamas (which, in a collective sense, also come under the denomination of camels) are asso- ciated in their native wilds with the guemal deer, which, like the rest of its kind, has horny hoofs of the normal type. Moreover, the wild ^longolian ponies inhabit the same tracts as the half-wild camels of the same country. All that can be said, therefore, is that we must take facts as we find them ; and that, for some reason with which we are unacquainted, the members of the camel tribe have developed a type of foot quite imlike that of any other ungulates, and well adapted, although by no means essential, to the countries where these animals are found. Away from such tracts, the feet of camels are, however, not infrequently a source of inconvenience, or it may be absolute helplessness, to their owners. For instance, on the smooth ^' kankar " roads of the Punjab, which in wet weather become sticky and slippery, camels are utterly unable to progress, their washlealher-like padded feel sliding from under thorn, and rendering them as helpless as a cat on ice. .\lthough, m a literal sense — that is to say, from the fact that they "chew the cud" — the members of the camel tribe are ruminants, yet they are structurally very different from the true ruminants — the Pecora of zoolo- gists— and are consequently referred to a separate group of equal value, for which the aforesaid name of Tylopoda is now in general use. In addition to their cushion-like feet, camels (including now and hereafter all the existing members of the group and their immediate ancestors under this title) are broadly distinguished from the true ruminants by the following fc^itures : — In the first place, instead of having the front of the upper jaw entirely toothless, the full series of three pairs of incisor teeth are present in the young, while in the adult the outermost of these pairs are an isolated curved and pointed tooth, and there is also a well-developed pair of canines, or tusks. Again, the lower canines, in place of being approximated to the incisors and resem- bling them in shape, retain the more usual isolated posi- tion and sharply-pointed form. As regards the cheek- teeth, although the majority of these are of the crescentic type characteristic of all ruminating mammals, yet there are certain peculiarities in form whereby they are readily distinguished from those of the true ruminants; and, what is more important still, one or more at the front of the series are usually detached from those behind, and assume a sharply-pointed form. In the skeleton the thigh-bone, or femur, is placed much more vertically, by which means the thigh is much more distinct from the flank, while the knee-joint is placed lower down than in the true ruminants. Another peculiarity is to be found in the unusual length and pointed form of the knee-cap, or patella. Then, again, none of the bones of the wrist and ankle-joints Ccarpus and tarsus) are welded together. As regards the lower part of the limbs, although the upper segments of the two remaining toes (the third and fourth of the typical series of ti\e) are welded together to form a cannon- bone (fig. I); yet they diverge to a much greater extent at their lower extremities than is the case with the true ruminants. Moreover, in place of each of the two lower articular surfaces of the cannon-bone having a projecting ridge to fit into a groove in the upper surface of the uppermost toe-bone, such surfaces are perfectly plain and smooth (fig. 1). Probably, owing to the nature of the foot itself, there is less liability to dislocation than in the hoofed feet of the true ruminants, and a " tongued joint " is therefore unnecessary. As regards the toe- bones themselves, it will suffice to say that the third or terminal pair form small irregular nodules, quite unlike the symmetrically flattened form characterising those of the true ruminants. 26 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. Perhaps, however, tht- ni'-i important peculiarity in the skeleton of the camels (and it will be unncessary on this occasion to refer to the soft-parts) is to be found in the vertebra- of the neck, which are unusually elongated. In all other mammals, with the exception of the extinct South American macrauchenia, the canal for one of the great arteries for the neck perforates the process pro- jecting from each side of the \ertebra' : but in the camels and macrauchenia it runs obliquely through the side- wall of the tube for the spinal marrow. Fig. 1.— Front Cannon-Bone of a Camel. All these features combined ser\'e to show that the camel tribe is widely separated from the true ruminants. How far back we have to go before we come to the common ancestral stock is indeed at present uncertain. Possibly both groups are independently derived from primitive ungulates in which tlie cheek-teeth had not yet de- veloped a crescentic type of structure. lie this as it may, it is quite certain that the ancestral camels had low-crowned cheek-teeth, comparable to those of the ancestral horses. Indeed, making due allowance for the fact that in the one case the modification has been carried on the artio- dactyle, and in the other on the perissodactyle plan (that is to say, with the enlargement of the third and fourth toes, instead of the third alone), the evolution of the camels has followed much the same lines as that of the horses. And this is only whatjmight have been expected, since, as stated in the previous article of this series, it is only on such lines that we can conceive evolution of this nature to be possible. /\s examples of this general similarity, or parallelism, I may refer, in the first place, to the enormous increase in bodily size which has taken place. Equally noticeable is the elongation of the bones of the lower segments of the limbs, coupled with the tendency to do away with double bones in such of those seg- ments as they exist, the suppression of the lateral digits, and the enlargement of those which remain. In both cases there is likewise a progression from low- crowned to tall-crowned cheek-teeth, and in both the development of a bar of bone beyond the eye so as to enclose its socket in a complete bony ring. The combination of all these factors tends (in addition to the augmentation of bodily size) to increase the speed and the longevity of the animals, and at the same time to render them fitted to subsist on the vegetation characteristic of the present and immediately preceding epochs ; the strengthening of the limbs so as to enable them to support the increased weight, and at the same time to withstand the strain of the increased speed, being, of course, an essential feature of the process. .^part from certain still older and more primitive mam- mals, with teeth of the tubercular type, the earliest known form which can definitely be included in the camel series is Piotylopiis, of the Llinta, or Upper Eocene period of North America. In this creature, which was not larger than a European hare, there was the full typical number of 44 teeth, which formed a regular series, without any long gaps, and with the canines but little taller than the incisors, while the hinder cheek-teeth, although of the crescentic type, were quite low-crowned. In both jaws the anterior front teeth were of a cutting and compressed type. Unfortunately, the skull is incomplete, and the rest of the skeleton very imperfectly known ; but sufficient of the former remains to show that the socket of the eye was open behind, and of the latter to indicate that in the hind foot, at any rate, the upper bones of the two func- tional toes had not coalesced into a cannon-bone. The lateral hind toes (that is to say, the 2nd and 5th of the typical series) had, however, already become rudimentary ; although it is thought probable that the corresponding digits of the fore-limb were functional, so that this foot was four-toed. \'ery remarkable is the fact that in old individuals the bones of the fore-arm (radius and ulna) became welded together about half-way down, although they remained free above. (_)n the other hand, it appears that the smaller bone of the leg (fibula) was welded to the larger one (tibia), and that itp upper portion had dis- appeared. Nothing is known of the neck-vertebra'. It is, of course, evident that there must have been an earlier form in which all the feet were four-toed, and the bones of the fore-arm and lower part of the leg separate. A stage higher in the series, namely, in the Oligocene, we meet with the much" better known Porhiotlieriuni, the skull of which (fig. 2) was described so long ago as i>^\'/. In this animal, which is also American, a distinct increase Fig. 2.— 5lvuli of Poebrotlierium in bodily size is noticeable, as is also one in the relative length of the two bones which unite in the higher types ot form the cannon-bone. Moreover, the crowns of the hinder cheek-teeth are rather taller and more distinctly crescentic, both feet are two-toed, the ulna and radius were fused, and the fibula was represented only by its lower part. In the vertebra^ of the neck the distinctive Mar., 1904.] KNO\VI.i:iH}E & SCIENTIFIC NEWS. 27 cameloid characters had already made their appearance. On the other hand, the skull (lie;. 21 was short and rabbit-like, showing none of the characteristic features of those df the modern canu'ls. Reaching the period of the Lower Miocene, we come to a genus, Gomphothtrium, in which there is a consider- able increase in the matter of bodily size, the two meta- podial bones (or those which unite in the later forms to constitute the cannon-bone) being fully double the length of the corresponding elements in Pivtylopus. Moreover, these bones, although still separate, ha\e their adjacent surfaces much more closely applied than is tiie case in the latter, .\gain, in tiiis and the earlier genera the terminal toe-bones indicate that the foot was of the normal hoofed type. On the other hand, in the skull (fig. 2) the socket of the ej'e is completely surrounded by bone: while the dentition begins to appro.vimate to the camel type — notably bj- the circumstance that the lower canine is either separated by a gap from the outermost incisor, or that its crown assumes a backwardly curved shape. Brief mention must suffice for I'roiolalris of the Middle Miocene, in which, while no cannon-bone is formed, the first and second pairs of incisor teeth are retained, and the limbs and feet are short and dispro- portionately small. In the Upper Miocene, on the other hand, we come to a very distinct type — Procamchis — which is clearly entitled to be regarded as a camel, and approximates in size to a small llama. Here the metapodials have at least partially united to form a cannon-bone : the skull has assumed the elongated form characteristic of modern camels, with the loss of the first and second pairs of rig. 3. — The Bones of the Mind-Foot of Poebrotherjum, showinf; the distinct metatarsars. uhich coalesce in the higher forms into the cannon -bone. upper incisors, and the development of gaps in front of and behind each of the next three teeth, that is to say, the third incisor, the canine, and the first cheek-tooth. The approximately contemporaneous Plianclienia makes another step by the loss of the second lower cheek-tooth. Both these genera have the toe-bones of the irregular nodular form distinctive of the modern camels, so that we may safely infer thai ihe fici themselves had assumed the cushion type. In one species of Pi'ocininiiis llic iiict.ipoilial hones coalesced into a cannon-bone late in life; but when we come to the Pleistocene Caiiiclops such union took place at an early stage of existence, and was thoroughly com- plete. In the living members of the group it occurs Fig. 4. Hind Cannon-bone of a modern Llama to contrast with the foot of ' ' f'oebrotheriiim,'* and to show the type characteristic of " Procamelas" and hlg:her forms. even before birth. The species of Camelops were pro- bably fully as large as llamas (including guanaco and vicuna), and some of them, at any rate, resembled these animals as regards the number of teeth, the incisors being reduced to one upper and three lower pairs, and the cheek-teeth to four or fi\-e in the upper and four in the lower jaw ; the total number of teeth thus being 28 or 30 in place of the 44 of Poehi-otlieii'mn. Tiie sole difference between Camelops and Llama seems to consist in certain structural details of the lower cheek-teeth. An allied extinct genus (Kschatiui) is also distinguished by certain features in the dentition. All the foregoing genera are exclusively North ,\merican. \ lower jaw from the F'leistocene deposits of that Continent has, however, been referred to the true camels (Camelas), w^hich differ from the llamas, among other features, by their greater bodily size, well developed hump, or humps, the presence of five pairs of lower cheek-teeth, and the complete bony ring round the socket of the eye. Outside America, remains of true camels are met with in the Lower Pliocene Siwalik strata of India, as well as in the Pleistocene of Soutli-Eastern Lurope and Algeria ; and it is noteworthy that the cheek-teeth of the Siwalik camel {Camelus sivalensis) display a structural feature now exhibited by those of the llamas. Prom Pleistocene or Pliocene in China have been obtained remains of a large camel-like animal named Paracamelus, which also shows certain signs of afiiiiity with the llamas in respect of its cheek-teeth. The above survey, brief as it is, suffices to show that the huge camels of the present day have been gradually e\olved from creatures not bigger than a hare, on lines closely paralleled in the case of the horse. In one 28 KNOWLEDGE & SCIENTIFIC NEWS. I Mar., 1904. respect the camels have indeed beaten the horse, haMn.^ entirely got rid of the splint-bones representing the outer- most pair of the original four toes. Further, in having exchanged the hoofed for the cushioned type of foot, they have undergone a kind of retrograde de\elopment. for which there is no parallel in the horse line. Fig' S. — Skull of Modern Camel, showing the reduced number of upper incisor teeth, and the ring of bone round the eye-socket. Here a brief diversion must be made to notice an extraordinary North American Miocene form, which is off the mam line. This is the giraffe-necked camel (Alti- camdas), a creature of the size of a giraffe, with similarly elongated neck and limbs, and evidently adapted for browsing on trees. The feet and number of teeth were generally similar to those of Procamelas. Unlike the giraffe, the length of the limbs is due to the elongation of the bones of the upper segments (femur and tibia) and not the cannon-bones : while the fore-limbs are not higher than the hind ones. The length of neck is due to the elongation of the anterior neck-vertebra-; if the hinder ones had been lengthened, the hei.ght of the body would have been increased without any compensating advantage. This creature affords one of the most extra- ordinarv instances of special adaptation known to science. The remaining space at my disposal must be devoted to certain considerations concerning the birth- place and geographical distribution of the group. It is claimed by Transatlantic pahfontologists that North America was the original home of the Camelidii, and so far as the earlier members of the group are concerned, there is nothing at present to justify a contradiction of this. The case is, however, \-ery different with the latter forms. We have seen that in North America the formation of a complete cannon-bone did not take place till tlie Pleistocene, at which epoch true camels also made their first appear- ance. But such camels, with complete cannon- bones, were in existence in India in the early pliocene. Ob\ iously, therefore, the evolution ot these animals must have taken place somewhere in Asia; this \iew being supported by the oc- currence there of the aforesaid Pnraeamelas. 1 lence it is quite probable that some of the earlier stages of the evolution of the group may have been carried out in ;\sia, when that conti- nent was united by way of Pehring Strait with North America. The Siwalik camel, it may be added, may ha\'e gi\en rise totlie existing two- humped Bactrian species ; while from the ex- tint t Russian and Roumanian camels the single humped Arabian species may have sprung. W'ith regard to the llamas of South America, palaeonto- logy goes to prove that the ancestral forms first obtained entry into that contintent from the north dur- ing the Pliocene period, when free communication was established between North and South America. Now all these ancestral forms, of which there are several distinct generic types, appear to have complete cannon- bones. Consequently, unless we are prepared to admit that these compound bones have been independently evolved in the camels and the llamas, the latter cannot have been derived from the known North American Pliocene forms, in which the union of the constituent elements of these compound bones was incomplete. Consequently, it seems a probable supposition — and this is supported by the above-mentioned structural resem- blance between the cheek-teeth of the Siwalik camel and those of the llamas — that the latter animals, like the true camels, were evolved in Eastern Central Asia, whence they reached South America by way of the Pacific border of the northern half of the New World, possibly over land long since submerged. The PKotogroLphy of Electric Spa^rks. The Photography of Some Electrical Phenomena was the subject of a lecture delivered on January 25, 1904, at the Camera Club, Charing Cross Road, by Dr. George H. Rodman. The lecturer commenced by describing t!ie method that he had adopted in obtaining the photographic repre- sentation of electric sparks from a lo-inch induction coil actuated by accumulators. It seemed to matter but little what voltage was used in the primary circuit, and the results shown were produced at a voltage varying from fi to 24 in the primar)'. Single Fo.siiive Di.scharge. Mar., 1904.] KNOWLEDGE c^- SCIENTIEIC NEWS. Sinsjle and multiple discharges were discussed ; the former occupying a very short space of time, possibly about of a second. Numerous representations of 20.000 '^ sparks taken under different conditions were shown, and Single Discharg:c bL-twccn Points. attention was called to the marked difference between the positive and negative discharge, the former having a brush-like appearance, and the latter invariably showed a characteristic fern-like representation on the plate. The lecturer showed excellent examples of the in- creased intensity of the spark when a spark gap was introduced into the secondary circuit, and in passing re- .Single Positive Discharge on Florir. marked that this was the e.xplanation of the use of a spark gap employed in connection with the sparking plug of motor vehicles. Examples of sparks from brushes and spheres, in addi- tion to ordinary point discharges, revealed many extra- ordinary effects ; and in all the characteristic features of the positi\e and negative discliarges were invariably present. The results. Dr. Kodman cxphiined, were obtained on Imperial platfs, wliicli were subsiMiuentiy developed in the usual manner with a pyio suda solution. The production of the photographic image of coins placed on the surface of the emulsion, and connected up with one or other terminals of the coil furnished some highly interesting results; and in these cases the characteristic features of the positive and negative discharges were well shown. On passing a single discharge on these coins with subsequent development of the latent image, a very distinct representation of the coin with its inscription clearly legible was produced, and the same effect was obtained in a much Single Negati\e Discllarge on Coin. clearer manner when a multiple discharge of current extending to i-2oth sec. was used. In this experiment when a discharge was produced with two coins attention was called to the remarkable appearance that the plate on development presented — the image of botli coins being multi])le. Dr. Rodman stated that he had up to the present been unable to deter- mine the cause of these multiple images, and, in order to arrive at a conclusion as to the cause of these nimbus-like shadows, had adopted various devices, but had failed with them to elucidate the matter. Assuming that they were the result of reflection, films had been used instead of the glass plates employed in tlie other experiments. Backed plates had also been made use of, but the multiple shadows still presented them- selves. To exclude the possibility of their being pro- 30 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. duced by retiection from the edf,'es of the coins, these had been painted with non-actinic colour. Finally, it was thought that the coins might have been thrown into a state of agitation, and had mo\-ed daring the passag'e of the current, and to exclude this possibility trend taken by speculations as to its origin. They have become more subtle, more far-reaching, yet less confi- dent. They have ramified in unexpected directions, but rather tentatively than with the full assurance of attain- ing absolute truth. Laplace considered only the solar system, from which he arbitrarily e.xcluded comets ; on the \ast sidereal world he bestowed barely casual attention. Sir William Herschel, on the other hand, occupied himself exclusively with the growth -processes of nebuUf, relegating the details of planetary evolution to a position of secondary importance. Later, the spectro- scope having become available for dis- criminating generic difl'erences among the suns in space, their relative ages, the order of their succession, their mutual affinities, laimed predominant attention. Just now. Sinj^le Positive Oischarge on two Coins. Both Coins in .Spherical Connection. they had been enclosed and supported in a couple ot circular holes made to fit the coins in a card at the time of exposure. This peculiar feature of the experiment was met with when coins of unequal size and of varying metals were employed, and was also noticed when the glass insulating plate was replaced by an india-rubber pad. Modern Cosmogonies. VII. Cosmogony in the Twentieth Century. By Miss .\gnes Clerkk, F.K.A.S. pROSPECTl\E and retrospectix e inquiries into physical conditions stand \ery much on the same footing. The same degree of uncertainty attaches to results of both kinds ; the same qualifications need to be applied to them ; a similar reserve is understood to accompany our admission of them. The reserve grows more marked as science unfolds to our surprised apprehension the multiplex possibilities of Nature. The time has gone by when " men of light and leading " could draw cheques for unlimited amounts on the bank of public credulity. Not that the balance has diminished, but that it is other- wise employed. Most of us, in these days, have learnt to "look before and after" for ourselves; and we in- stincti\ely mix the pr(j\erbial grain of salt with what is told to us, even on the highest authority. Ideas are on the move ; dim vistas are opening out ; much that lies lieyond the verge of actual experience is seen to be possible, and sedate reasoning may at any moment suffer outrage by fantastic discovery. Hence, dogmatism is at a discount. The secular parallax allccting men's views of the universe is nowhere more strongly apparent than in the however, the flood of ideas is too high to be restrained within separate channels ; cosniogonists look far afield ; they aim at obtaining a general sur\ey of relations baffling in their complexity. To some ex- tent they have succeeded ; parts are beginning to find their places in a great whole ; links are seen to connect phenomena at first sight seemingly isolated ; on all sides, analogies are springing into view. The unwearied circling of the moon, and its imperturbable face, remind us how a sun may have been born ; the fiash of every meteor suggests the mode by which suns die. The filmy traceries of comets intimate the nature of the force acting in nebulae ; the great cosmic law of spirality is distantly hmted at by the antipodal disturb- ances of the sun. Thus, one set of facts dovetails into the next ; none can be properly considered apart from the rest. The limitations of the human mind, nevertheless, require a subdivision of labour. Individual efforts can- not grapple with the whole of the known and the know- able ; and the larger part of both is included in the scope of modern cosmogony. It deals with all that the skies hold, visibly or invisibly ; draws unstintingly on time past and time to come ; concerns itself equally with gradual transformations and sudden catastrophes, with the dissipation and concentration of energy, with the subtle interplay of matter and force, with physical and ultra-physical, chemical and electrical modes of action. But let us consider a little more particularly how things actually stand, so as to collect some definite ideas regard- ing the lines of advance practicable and promising for the immediate future. To begin with our domestic circle. The insecure state to which Laplace's scheme has been reduced by the assaults of numerous objectors has found compensation in the development of tidal theory. Much light has thereby been thrown upon planetary pre-history. The relations of planets to the sun, and of satellites to planets, have been rendered comparatively intelligible. Notice- able above all is the discovery thence ensuing of the earth's critical situation, just outside the boundary of the region where planetary rotation was destroyed by sun- raised tides, and with it the prospects of planetary vitality. Moreover, the consequent dubious state of the inchoate terrestrial spheroid accounts for the peculiar mode of birth of the moon, and the distinctively binary character of the earth-moon system; while the variety perceptible in the circumstances of the different planets precludes the employment of any single recipe for their Mar., 1904.] KNOWLEDGE c\: SCIENTIFIC NEWS. 31 development from a primal vortex. The forces concerned, we can now see, acted in a far more complex manner than could formerly have been supposed ; and their balance was proportionately more delicate. To which side it would have inclined in a given case must tiien often be incalculable, or calculable only with the guid- ance of the known result. The strict bonds of reasoning have tlius become somewhat relaxed, and difficulties tiiat looked formidable have, in the long run, proved not to be insuperable. But conviction has also grown faint. The old, imposing fai;ade of theory remains erect ; the building behind it has been for the most part pulletl to pieces, and the architect has yet to be found who can reconstruct it to our satisfaction. On one point we have, nevertheless, acquired certainty. It is now known that comets with their dependent trains of meteors are aboriginal in the solar system. They are no unlicensed intruders, but collateral relations of the planetary family. Possibly, they represent waste scraps of world-stuff which escaped the action of the formative machinery ; and if so, they exemplify its primitive tex- ture. Not that their composition need be, on this sup- position, identical with that of the planets. A sifting of elements would have been likely to accompany the pro- cesses of cooling and contraction. Comets were perhaps made (so to speak) of the white of the nebulous egg, planets of its yolk. But in any case, we may safely regard the glimmering fabrics of acetylene and cyanogen that occasionally illuminate our skies as shearings from a wide-spreading, fleecy haze, flung aside before " the starry tides " had as yet begun to " set towards the centre." In one respect, the quality of these relics is a surprise. They show no chemical affinity with nebula?. Their spectra are radically different from nebular spectra, gaseous or continuous. They accord- ingly lend no countenance, although not fatally adverse to the view that the sun was once, in the distinctive sense, a nebulous star. The grand topic of sidereal succession is no longer abandoned to fruitless surmises. Broad lines have been laid down, along which — so far as we can at present see — progress must inevitably have been conducted. And one fact of overwhelming significance in this connection is entirely of recent discovery. The multitudinous existence of obscure bodies in space had, indeed, been foreseen as a logical necessity long before Bessel founded the " Astronomy of the Invisible" ; but it has been sub- stantiated almost wholly by modern spectrographic methods. Decrepit or dusky suns are assuredly no imagmary product, but a potent reality ; though it would be too much to assert that all have sunk to extinction by the same road. We stand, too, on firmer ground than our predecessors in respect to the history of stellar systems. That its course is mainly prescribed by the influence of tidal friction has been ably demonstrated by Dr. See. Tele- scopic double stars can be led back, by the aid of this clue, to an initial stage, when they revolved close together, very much like the earth and moon in Professor Darwin's theory ; and it was owing to their v oluminous- ness, and the unequal attractions it engendered, that their orbits became enlarged and elongated to the degree generally observed. Spectroscopic binaries, moreover, illustrate earlier modes of circulation ; they present us with couples fully separated, and still separatmg, as well as with others barely divided, and revolving almost in contact. Nay, they include specimens, we are led to believe, of globes conjoined into the apioidal figure theoretically investigated by Darwin and Poincare, which may be regardedas preparatory to the dev elopment, ' by iission, of two mutually revolving stars from one primitive rotating mass. One of these supposed dumb bell systems is the variable V Puppis ; and if tlie eclipse- rationale of its obscurations be confirmed by the spectro- scope, there is no gainsaying the inference that it is com- posed of two stars actually contiguous, if not commingloil. Now compound stars are by no means of exceptional occurrence. Their relative abundance has been found to augment rapidly with every advance in our knowledge of the lieavens. From the measures of stellar radial velocity lately carried on at the Ycrkes Observatory by Professors l'"rosl and Adams, it appears that the propor- tion of binary to single stars considerably exceeds Pro- fessor Campbell's earlier estimate. Of those giving helium-spectra, at any rate, there are most probably as many of one kind as of the other. But why the distinc- tion, it may be asked ; and the answer is not far to seek. Helium-stars are the most primitive, and form the closest, and most readily apparent systems. A physically double star must always remain such. There is no law of divorce by which it can put away its companion, although their relations must alter with time. But their alteration tends continually to enhance the difficulty of their detection. For as the members of a pair are pushed asunder by tidal friction, their velocity slackens, and the tell-tale swing of their spectral lines diminishes in amplitude, and finally, by its minuteness, evades observation. And since the majority of spectro- scopic satellite-stars are very imperfectly luminous, their eventual telescopic discovery, when far enough away from their primaries to be optically separable from them, would rarely ensue. It must then be concluded that half the stars in the heavens (let us say) broke up into two or more bodies as they condensed. What follows? Well this. Half the stars in the heavens were, from the first, incapacitated from becoming the centres of planetary systems. To our apprehension, at least, it appears obvious that a binary condition must have inhibited the operations of planetary growth. These innumerable systems are doubtless organised on a totally different principle from that regulating the family of the sun. The Nebular Hypothesis, even in its most improved form, has no application to them ; the Rleteoritic Hypothesis still less. Mathematical theories of fluid equilibrium, com- bined with a long series of changes due to tidal friction, afford some degree of insight into the mode of their origin and the course of their development. Yet the analogy with the earth-moon couple, which irre- sistibly suggests itself, is imperfect, and may be mislead- ing, owing to the wide difference in state between plastic globes approaching solidification and sun-like bodies, radiating intensely and probably gaseous to the core. The world of nebulae presents us with complete cycles of evolutionary problems, which can no longer be treated in the offhand manner perforce adopted by Herschel. The objects in (luestion are of bewildering variety ; yet we can trace, amid their fantastic irregularities, the underlying uniformity of one constructive thought. Nearly all show, more or less markedly, a spiral con- formation ;' and a spiral conformation intimates the action of known, or discoverable laws. 1 heir investiga- tion must indeed be slow and toilsome ; its progress may long be impeded by the interposition of novel questions, both in physics and mechanics ; nevertheless, the lines prescribed for it seem definite enough to give hope of its leading finally to a clear issue. And when at last some- thing has been fairly well ascertained regarding the past and future of nebulous spirals, no contemptible inroad will have been made on the stupendous enigma of sidereal relationships. 32 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1934. Its aspect, if we venture to look at it in its entirety, is vast and formidable. Not now, as in former times, with a mere fragment of creation — a single star and its puny client-globes, one of which happens to be the temporary abode of the human race — but with the undivided, abysmal cosmos, the science of origin and destiny con- cerns itself. The obscure and immeasurable uncertain- ties of galactic history invite, or compel attention. We know just enough to whet our desire to know a great deal more. The distribution of stars and nebulae is easily seen to be the outcome of design. By what means, w-e cannot but ask ourselves, was the design executed ? How were things ordered when those means began to be em- ployed ? How will they be ordered when all is done ? For an ultimate condition has, presumably, not yet baen reached. And if not, agencies must be at work for the perfecting of the supreme purpose, which are not, perhaps, too subtle for our apprehension. Meanwhile, facts bearing on sidereal construction are being diligently collected and sifted ; and we shall do well to suspend speculation until their larger import is made known. The inquisitions of science do not cease here. They stri\e to penetrate a deeper mystery than that of the scattering in space of stars and nebulie. What are they made of is the further question that presents itself. What is the nature of the primal world-stuff? Whence did it obtain heat ? By what means was motion im- parted to it ? If it be urged that such-like topics elude the grasp of finite intelligence, and belong to the secrets of Creative Power, we may reply that we are not entitled, nor are we able to draw an arbitrary line, and impose a nc plus ultra on our thoughts. Tiie world has been, by e.xpress decree, thrown wide to their excursions, and it is not for us to restrict their freedom. W'e need not fear getting too near the heart of the mystery ; there is no terminus in the Unknown to which we can travel by express: in a sense, we are always starting, and never get nearer to our destination. But that is because it retreats before us. We do, in truth, advance ; and as we advance, the mists clear, and we see glimpses beyond of imperishable order, of impenetrable splendour. Our enquiries need not then be abandoned in despair at the far-reaching character they have spontaneously assumed. From the earliest times there has been a tendency to regard varieties of matter as derivative. They have been supposed to be procured, by supra-mundane agency, or by the operation of inherent law, from some universal, undifferentiated substance. We moderns call that sub- stance " Protyle,"" and believe ourselves to be in experi- mental touch with it. The implications of this view we shall consider in the next chapter. ' A term signifying " first matter," constructed from corre-pjnd- ing (ireek words by Roger Bacon, and revived by Sir William Crookes. The Conductivity of Seleniunrv. Mr. E. A. llopius, in an investigation recently presented to the Russian Physico-Chemical Society, has made a series of experiments with an apparatus constructed by Mr. M. Kohl and another apparatus designed by himself on selenium sup- plied by the firm of E. MerU, Darmstadt, the former apparatus beinf; illuminated by a standard amy! acetate burner at dis- tances ranging from 10-200 cm., and the other by a Nernst lamp placed at the same distance. The measured current intensity agreed fairly well with the hypothesis of a direct proportionality between the increase in the conductivity of selenium and the cubic root of the intensity of illumination. Borings on Ql Corad IslacHLd. The Atoll of Fvinafviti. Xeari.v a quarter of a century ago Charles Darwin penned the following words in a letter to Prof. .Alexander Agassiz : " I wish that some doubly rich millionaire would take it into his head to have borings made in some of the Pacific and Indian atolls, and bring home cores for slicing from a depth of 500 or 600 feet." The pro- found interest which Darwin had himself long previously aroused by his theories regarding the structure of coral reefs and their mode of origin could not do otherwise than henceforth make the subject an integral part of geological science, and one. too, of striking significance. It was, therefore, to be expected that the hopeful words of the master-naturalist would ripen with time to bear fruit in effort. Not, however, until 1893 did Sand iv/'t/i some cora/ b/ocks. ■M. ■52 ft. 9 in. '■■'.^- SCII-XTIFIC NEWS. 35 sun's rays and the powers of endurance to lieat of corals and of Lithothaiimion, a point on which Darwin had speculated. It seems that except the Poiitcs, all other forms of coral succumbed within two hours' exposure, and it was evident that the essential life-gift alike to coral and plant was a constant supply of fresh sea-water. Among the contributions to the monograph certainly the most industrious of all is Dr. Hinde's report on his examination of thin sections of the materials obtained from the reef borings and those made beneath the lloor of the lagoon. Upwards of 500 microscopic surface slittings were prepared for diagnosis in Professor Judd's geological laboratory at the Royal College of Science. .\s already mentioned, the main boring, begun in 1897, was taken down to 1114^ feet, and it may be added that the diameters of the cores brought up in the drilling apparatus were, top to 68 feet, about 4 inches; 68-210 feet, about 3J inches; 210 toboring limit, about 2| inches. .\11 these cores ranged in length from i inch to 3 feet. Dr. Hinde supplies an elaborate description of a detailed inspection of the several lengths of core that were placed under examination for the detection of organisms, and we cannot do better than quote here Professor Judd s general conclusion thereon, namely, that " from top to bottom the same organisms occur, sometimes plants, sometimes fora- minifera, and sometimes corals predominating ; but in the whole depth bored the same genera and species of these various groups of organisms take their part in the "build- ing up of the mass." (Fig. 5). .\ large amount of space would be necessary to even summarize the many points of research apart from boring and sounding operations embraced by this truly classic exploration in the far Pacilic. There was made, however, we must not omit to mention, a magnetic sur- vey by H.M.S. Penguin (Captain Field) ; a series of meteorological observations ; and a thorough study of the natural history of the island of Funafuti. The numerous helpers in the two continents have reason to be proud of the evidence of their long-continued efforts, and undoubtedly the scientific results of the sur- vey will prove of the utmost value in current discus- sions which concern the present-day re\ised \ iew of the development of coral reefs. Modem Views of Chemistry. By 11. J. H. Fenton, F.K.S. It may happen that there are some of our readers who are interested in the study of Chemistry, but who have not had the time or opportunity of following the very rapid and important advances which have been made in the science, especially in the departments of physical and organic Chemistry. In the present articles, which are addressed to readers of this class, it is proposed to give brief sketches in outline of some of the more im- portant developments which have occurred during recent years. We will in the first place refer to the great changes which have occurred in our views with regard to the nature of solution and the chemical and physical changes which may take place in dissolved substances ; the advance of knowledge in this department has resulted in what is sometimes called the •' New Cheniistr}-," which would scarcely be recognised as the same science by one who had been a good chemist twenty-livf years ago, hut who had not kept pace with the times. It may be mentioned in passing that it was the custom formerly to restrict the term "solution" to liquid mix- tures— that is to solids, liquiils, or gases dissolved in licjuids; hut we may now speak of solutions of gases in solids and even of solids in solids ; a solution IS in fact, generally speaking, any homogeneous mixture of two (or more) substances in which the pro- portions may, within certain limits, be varied con- tinuously. I'sually one speaks of one of the constituents as the solvent and the other as the dissolved substance or "solute " ; but this is only an arbitrary dis- tinction. In the case of an aqueous solution of common salt, for example, we might regard the mixture either as a solution of salt in water or of water in salt; for if a dilute solution be sufficiently cooled it becomes saturated with respect to water, and solid water (ice) separates out, leasing a stronger solution of salt, just as when a \'ery strong solution is cooled it becotnes saturated with re- spect to salt, and the latter separates in the solid state, leaving a weaker solution of salt, i.e.. a stronger solution of water. It was at one lime thought that solution con- sisted in a sort of loose chemical combination between the sohent and dissolved substance, and this idea seemed to be supported by the fact that many salts and other sub- stances combine with water to form definite hydrates, which may be isolated in the crystalline form. But it does not follow that tliese hydrates continue to exist when the substance is in solution, and the probability is that, in dilute solution at any rate, they do not exist. Certain membranes exist naturally, and may be pre- pared artificially, which will allow water to pass through them, but will not allow the passage of dissolved sub- stances such as sugar, salt, &c. If now one separates a solution of sugar from pure water by means of a mem- brane of this kind water will pass both ways through the membrane, but more will pass into the sugar solution than out of it, so that its volume tends to become larger and the solution weaker. If, however, the volume of the solution IS kept constant, that is, if it is not allowed to ex- pand, the pressure will increase instead, and will con- tinue to do so until a certain maximum pressure is reached. This maximum (osmotic) pressure depends upon the temperature, the strength (or concentration) of the solution, and the nature of the dissolved substance. It is found to vary with the temperature and concentration according to the same laws which regulate the pressure of a gas, and, further, the actual pressure produced is the same as that which would be exerted by the same sub- stance (theoretically in the case of sugar) if it were in the state of gas at the same temperature and volume. A large class of substances (such as sugar, urea, and most other organic substances) behave, therefore, in exactly the same way when dissolved in a solvent as they would in the gaseous state — as regards the relations between temperature, concentration, and pressure — only that what we understand by " pressure " in the gas state must be interpreted as "osmotic pressure" in the case of solutions. By making use of Avogadro's hypothesis— that ecjual \olumes of gases contain, at the same temperature and pressure, the same number of molecules — we can com- pare the molecular weights of gaseous elements or com- pounds by weighing equal volumes of them under the same conditions; and now by extending this hypothesis to substances dissolved in liquids we can compare their molecular weights in a similar way. It may be done in the latter case by measuring (directly or indirectly) the 36 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. osmotic pressure which is produced at a certain tempe- rature and volume by a given weight of the substance. If we apply this method to the determination of mole- cular weights of substances in water solutions, it is found that, although most of the organic (and some inorganic) compounds give perfectly normal results — (results, that is, which agree with vapour density determinations and with general chemical considerations) — most salts, acids, and bases give results which are apparently abnormal, the osmotic pressure produced being too high. A dilute solution of potassium chloride, for example, gives an osmotic pressure almost exactly double of that to be expected by the application of Avogadro's hypothesis. That is to say that one molecular weight of potassium chloride gives twice the osmotic pressure which one molecular weight of sugar (urea, &c.) gives under the same conditions. It was suggested that this result might be explained by supposing that the salt is " hydrolysed " by the water — i.e., that caustic potash and hydrochloric acid are produced. Since they would be formed in exactly equi- valent quantities, it would not, of course, be possible to detect their presence by the ordinary tests. But such an explanation will not account for the fact that hydrochloric acid itself behaves " abnormally " also, giving about double the expected effect. The theory of Arrhenius not only accounts for all these "abnormalities," but offers in addition a most elegant explanation of a large number of facts in connection with the behaviour of salts and other substances in solution, including the phenomena of electrolysis. This theory assumes that most salts, and the strong acids and bases, are largely if not entirely dissociated when dissolved in water (and in some other solvents) into constituent parts or " ions," and that these ions differ from the same sub- stances, as we know them in the separated state, in that they are associated with enormous electric charges. A molecule of potassium chloride, for example, dissociates into an atom of potassium associated with a positive charge, and a chlorine atom with an equal and opposite negative charge. These charges are given up at the respective electrodes when the salt is electrolysed and the potassium and chlorine are obtained in their ordinary " neutral " state. A revolutionary hypothesis of this kind was viewed, perhaps naturally, in the first instance with suspicion and dislike, and even at the present day it is not quite univer- sally accepted, but the active opponents, at any rate those who have the courage of their opinions, are becoming daily few and far between. The application of this ionic dissociation hypothesis in explaining various well-known chemical phenomena is an extremely fasci- nating study and it is proposed to give various examples in illustration of the application at a future time, fust one may be mentioned here in conclusion. A question which agitated the minds of chemists for a great number of years was of the following form: What happens when two different salts— say, sodium chloride and potassium nitrate— are mixed together in aqueous solution ? Do they remain as they are or do they " change partners," forming sodium nitrate and potassium chloride? A large number of experiments were made with a view of throwing light upon this question, but in most cases the problem appeared to be incapable of solution. It was apparently of no use to attempt the isolation of the differ- ent salts since the equilibrium would be disturbed by their removal, and it seemed only admissibletn employ methods which required no removal from or addition to the solution. Attempts were made, for example, to throw light upon the problem by observing the thermal, volume, or colour changes which occurred on mixing the solutions, and although a certain amount of information was gained by such methods, they were in most cases anything but con- clusive. This much-debated question then — which metal is united with which acid-radicle ?— is (as a general case in dilute aqueous solutions) now at once disposed of by the ionic dissociation hypothesis, which gives the answer — No metal is united to any acid-radicle ! Wind-Driven Electricity Works. l>y Dr. Ali-red Gradenwitz. Professor Latour, of the Askov Popular Academy (Denmark), has for some years b^en engaged on behalf of the Danish (jo\'ernment in investigating the problem of utilising wind power in connection with small electricity works. If, however, the dynamo be direct-coupled to the wind motor, the results obtained are unsatisfactory on account of the exceedingly variable speed of the wind. As pointed out in an address recently delivered by Professor Latour before the Copenhagen Technical and Hygienic Congress, he was met with difficulties in designing a suit- able regulator for controlling the speed of the dynamo. At present, however, these difficulties appear to have been overcome, and an electricity central station near Askov has been worked with wind power for a year with satisfactory results. The arrangement of a similar electricity works is repre- sented diagrammatically in fig. i. The regulating device itself is made up of two different parts. The mechanical regulating device is intended for maintaining at constant values the peripheric force transmitted to the belt disc of the dynamo. The two belt discs R R are mounted on a movable arm A, bearing a counterweight P. The resulting tension of the belt is thus kept constant, depend- ing on the weight of the belt discs as well as on the counter- weight P. The ratio of the resulting belt tension and the maximum peripheric force susceptible of being trans- mitted by the belts is, however, practically constant. The peripheric force transmitted by the wind motor to the belt disc R accordingly cannot exceed a given value, the torque of the dynamo remaining below a corresponding value. Any surplus energy developed by the wind motor is lost as heat with the friction of the belt. A constant torque of the dynamo axle will, however, correspond with a constant current intensity in the armature. In the case of the magnetising intensity employed, the load is in fact Fig. I. M' 1 004.] KNOWLEDGE .S; SCIENTIFIC NEWS. 2,7 practically proportional to the speed, so that the intensity of the current may be regarded as constant. This is further demonstrated by the author's measurements. The current from the dynamo is used to charge an accu- mulator battery represented diagramniatically in P'ig. i. The cut out switch F is closed, pro\ided the current in- tensity be not inferior to its normal constant value. The dynamo D therefore works at a variable speed. In the case of the wind being so strong as to absorb part of the energy by the friction of the belt, the system will work in the following way : .\ssummg the accumulator battery to be nearly discharged and the crank of the cell controller to be adjusted for the total charge of the battery, llie dynamo will run at a speed so high as to be quite suffi- cient to charge the battery with the normal current of a dynamo (e.g. 50 amp.). As the charge increases, the dynamo will automatically increase its speed and load so as to make the charging current constant. The cell- controller will have to be resorted to in charging in exceptional cases only — if, for instance, the charging and discharge of the battery takes place at the same time. The electrical regulating device is situated in the inter- rupter S, being mainly an ordinary minimum current interrupter, disconnecting the dynamo as soon as the current decreases below the normal number of amperes. This arrangement is necessary to prevent the accumu- lator battery from being discharged through the dynamo when the strength of the wind is small. The interrupter, however, will automatically insert the current as soon as the wind again assumes a greater strength. To attain this result, the current interrupter is provided with a ten- sion regulator, inserting the current as soon as the speed of the dynamo has sufficiently increased. In the case of variable strengths of the wind, the plant may thus accumu- late any amount of wind available, the interrupter open- ing and closing the connections continually. On the switchboard there are in addition two ammeters and one voltmeter. A small electricity works arranged in accordance with the foregoing principle has, as above mentioned, been in operation in Askov since the beginning of last autumn, supplying the inhabitants of the neighbouring commu- nities with electric current. The constant normal current supplied by this installation is 60 amps, at tension of 220 volts. As a reserve, however, in cases of several days' calm weather, a petroleum motor had to be installed. The plant has so far given every satisfaction, requiring no superintendence worth speaking of. The man in charge of the machine was away fer|whole days, so that there was no supervision except "Jin^^the morning and the The W'ork.s at A.skov. evening. The capacity of the accumulator battery is sufficient to supply the maximum amount of energy required during 48 hours. As regards the economical side of the question : The (irst cost at .'VsK-on- has been about 16,000 Kr. (a Kroner is about is. id.), out of which 3000 Kr. are set aside for the cost of pstroleum nioliir. The electric current is supplied to consumers at the same price as in Copenhagen. The receipts for energy sold work out at about 2800 Kr., and the expenses al about 800 Kr. per year. There will thus remain 2000 Kr. for the amortisation of the plant, which is more than sufficient with a capita! of i6,ooo Kr. The price of energy could therefore be further diminished. In ihe case ofsniall electricity works intended for the use of a limited number of houses, the petroleum motor may be replaced by a horse-driven contrivance. Moreover, in the case of the proprietor of the works being his own consumer, the consumption of current may be regulated according to the actual intensity of the wind; in the case of calm weather, there will for instance have to be no thrashing done, cVc. The first cost will thus be considcraoly diminished; according to I'ref. Latour's calculation, a plant suitable for a farm would be installed at a cost of 3000 to 4000 Kr. The Canals on Mars. Ix a communication to the Royal Astronomical Society on June 12, 1903, as reported in the Olwrvaloi'v for July, Mr. Maunder called in question the objective reality of the canals on Mars, explaining them away as psycho- logical phenomena " due to the integration by the eye of markings far too small to be observed by the observer." He based his argument on the fact that copies of draw- ings of Mars without the canals, made by beys of from 12 to 15 years of age placed at \'arieus distances from the drawings, contained lines resembling canals amounting to five canals per head as a maximum at a distance of 25 feet, the diameter of the disk being about 6 inches. Unfortunately, the report gives us no information as to the closeness of coincidence of the lines with canals that have been actually observed, nor even as to the agree- ment between the lines drawn by different boys. It is difficult to see hew the drawings to be copied could have contained actual Martian markings that were " far too small to be observed," whose integration produced lines in the positions in which canals have been observed ; but if the drawings were not sufficiently accurate to show such markings, the lines must have been produced by markings peculiar to the several drawings, whose resem- blance to anything on the planet is highly improbable. In drawing inferences from a comparison of artificial experiments with natural phenomena, it is certainly essential to the value of the results that the artificial and natural phenomena shall be substantially identical, and that the observations shall be made under practically the same conditions in both cases. On a later occasion, Mr. Maunder himself strenuously insists upon the necessity for a very close resemblance between the phenomena and between the conditions of observation in such cases. In criticising Mr. Lowell's application of the results of his experiments on the " visibility of fine lines " (the Oliscrva- tory for September, 1903), Mr. Maunder says "there is actually no resemblance between the case of observing a wire in space and that of observing a line drawn on a surface " ; nevertheless, he seems to find a sufficiently close resemblance between the observation of a flat picture (inaccurate, at best) with the naked eye in a 38 KNOWLEDGE .K: SCIENTIFIC NEWS. [Mar., IC04. lighted room, and the observation of an illuminated ball surrounded by the blackness of night, seen through the mirage of its own atmosphere by means of a telescope. Those who draw conclusions from observations should be very careful in their reasoning, bearing in mind that induction, while a powerful instrument in the construc- tion of theories, is absolutely useless in their proof or disproof. A theory of physical phenomena can be dis- proved only by showing that it leads by deductive reasoning to necessary conclusions that are inconsistent with observed facts. ;\Ir. jMaunder's theory may explain sufficiently well the lines on the copies of his drawings, but it no more suffices to disprove the objective reality of the canals observed on Mars than it does to prove that there are only fi\-e canals, as seen by his boys. The fact that an effect may be due to one cause, while it may certainly also be due to another, affords no pre- sumption that it is due to the first rather than to the second, especially when the one explanation is based upon artificial experiments and the other is natural. Mr. Maunder's argument assumes that the canals are seen as very faint lines, so faint that their existence is doubtful even to experienced observers ; this may be true when they are observed through any but an exceptional atmosphere — and the atmosphere of Flagstaff is one of the exceptions. There, even under ordinary conditions, at the proper Martian season most of them are so easily and certainly seen that there is no reasonable doubt about them. Before Mr. Maunder ever disco\ered the psychical effect, Mr. Lowell was perfectly aware of it himself, and had studied it experimentally, which experiments he has continued to the present time, with the result that he finds a clear line of demarcation between confusion of real and imaginary up to a certain degree of definite- ness of the real, and an instant consciousness of the dif- ference between the two above that limit. The brain is not only conscious of the image, but directly conscious of reality as opposed to illusion. If Mr. Maunder's drawings had contained some canals for comparison with the imaginary lines, this difterence would probably have been apparent. The beha\iour of the canals, their waxing and waning with the advance of the Martian seasons, is proof positive that they are not due to the integration by eye of perma- nent faint markings, and it is more difficult to account for the gradual and regular advance and retreat of such markings along the line of a canal than for the growth and decadence of the canal itself. Mr. Maunder's ex- planation seems to substitute an uncertain and almost impossible phenomenon for a very certain and probable one._ From 8,500 determinations of the canals, Mr. Lowell has recently shown that they come into sight after the melting of the polar cap in times that are directly proportional to their distances from that cap measured in latitude. The enormous improbability of any such agreement in 375 drawings, the number he used, is so great as to run into the millions to one. The logical conclusion of Mr. Maunder's argument, if valid, is that no faith is to be put in the reality of things seen, if anybody has e\ er been deceived in the appearance of such things. The scientific \-alue of facts would then be liable to complete emasculation by the ignorance carelessness, or male\olence of an observer. It is time an end should be put to the inquisitorial fashion of re- fusing credence to scientific discoveries until they shall have received the official recognition of the self-constituted authorities, especially when those authorities do not represent experts in the subject in (juestion. That it is useless to continue the observation of planetary detail, because henceforth no reliance can be placed on what observers may tell us they have seen of such, can only be the doctrine of what may be called an " impressionist " school of science. If Mr. Maunder claims that his ex- planation is simply one mode of accounting for the appearance of the canals, he is practically throwing doubt upon their existence without taking the responsi- bility for it. In the course of the discussion of Mr. ]\Iaunder's com- munication, Professor Newcomb said : " We all know how one improves by practice, and I think there is such a thing as improvement of the art of seeing things dif- ferent from what they really are." This is a gratuitous slur upon scientific obser\ation, to be justified only by the heat of a violent quarrel, and inexplicable under the present circumstances. Surely, Professor Newcomb cannot believe that the statements of an observer are any the less credible because he has had experience ? No ; these experiments show conclusively that observers must be trained to their work, that even descriptions of phenomena are of little value unless made by those who are experienced in observing phenomena of the kind de- scribed. The reports of such observers must be accepted as truly indicative of fact until they shall have been proved to be false, which can be done only by direct appeal to observation. Williaii Edward Story. Worcester, Mass., U.S.A., January 2, 1904. [Mr. Story criticises the paper communicated by Mr. Evans and myself to the R AS. without first having done us the honour of reading it. This method has some disadvantages; one being that many of Mr, Story's remarlis have no bearing at all on the questions with which we actually dealt. Want of space pre- vents my dealing with the details of Mr. Story's paper in the present number of "Knowledge," but if the subject suffi- ciently interests its readers I may return to it on a later occasion. For the present, it is sufficient to enter a strong protest against Mr. Story's quite uncalled-for attack upon Professor Newcomb. — E. Walter Malnder.] The Obelisk of Mo\ii\t Pelee. Wb. reproduce herewith a remarkable photograph taken by Mr. E. O. Hovey, for which we are indebted to our contemporary, the Scientific American. It represents one of the most peculiar and interesting phenomena of the recent eruptions of Mount Pelee. This was the growth of the tooth-like column of rock which arose out of the centre of the crater. It was first observed (by Professor Lacroix) in October, 1902, amid the dense smoke and steam overhanging the mountain. It was then estimated to be about 295 feet above the rim of the old crater. Put subsequent observations proved it to be steadily growing, and after some months had attained a height of over 1000 feet. Professor Heilprin noted a growth of about 20 feet in four days. \'arious explosions and movements of the earth altered the relative height of the obelisk. It rose and fell and large portions became detached. Bit by bit it then receded again, sinking as much as 150 feet during one night, but frequently rising again temporarily. This continued during many months, till finally it disappeared within the cone. The cause of this curious apparition can but be vaguely surmised. It has been suggested that the vent of the volcano in olden days had become filled with solidified lava, and when the first outbreak occurred this whole mass was raised bodily up, as a cork is forced upward from a bottle. ■ K'iowie.l;f .'- S. iV itr/i.- .Vft,s." ^^ The Obelisk of Morvt Pelee. Mar., 1904.] KNOWLEDGE cS: SCIENTIFIC NEWS. 39 The Face of the Sky for MarcK. By \\. Shackleton, F.K.A.S. The Si'N. — On the ist the Sun rises at 6.4S, and sets at 5.3S: on the 31st he rises at 5.4.1, and sets at 6.2q. The vernal equinox occurs on the 21st, when the Sun enters the Sign of Aries at i a.m. and Spring commences. Sunspots may frequently be observed, and for plotting their posiiions the following table may be used. Date. Mar. I .. II .. 21 .. 31 Axis inclined to \V. from N. point. 21'' 48' 24^ o' 25° 31' 26" 21' Centre of disc, S of Sun's equator. 7' 14' 7" 12' f>' 57' 6 30' Date. Phases. Mar 2 .. .. 0 ■• .. 17 •• ., 24 .. .. 31 •• 0 C Full Moon I^si Qnarier New .Moon First Quarter Full Moon II. M. 2 48 a.m. I r am 5 39 am 9 37P-m- o 44 p.m. The Zodiacal light should be looked for in the west for a few hours after sunset. The Moo.v : — The Moon is in perigee on the 1st and 29th and in apogee on the 14111. Occulta-tions. The following 'are the more interesting occultations \-isible at Greenwich during convenient hours ; it will be seen that on the 22nd the Moon is in the Hyades : — Saturn is a morning star rising a little more than ,in hour before the sun. Uranus rises after midnight and is situated rather low down in the sky near the star 4 Sagittarii. Neptune, as will he seen on reference to the chart in the January number, is about midway and 10' south of the line joining the stars v and u Geminorum. Telescopic Objects: — Double Stars. — y Leonis, X.'' 14'", N. 20' 22', mags. 2, 4; separation 3"-8. In stead\'air, the prime reciuisite for double star observations, tliis double inav he well feen in a 3-in. telescope with an eyepiece magnifying about 30 to the inch of aperture, hut on most nights one with a power of 40 is better. The brighter component is of a bright orange tint, whilst the fainter is more yellow. 1 Leonis, XI.'' 19'", N. 115', mags. 4^, 7A ; separa- tion 2"-2. A pretty double of different coloured stars the brighter being yellow, the other blue. This object requires a favourable night and a fairly high power on small telescopes. a Leonis {I\ff;iiliis) has a small attem'ant about i ScV distant, and of the >^'5 magnitude, and easily seen in a 3-inch telescope. u. Canum X'enat. (Co;- Cai'oli), XII.'' 52", N. 38' 50', mags. 2-5, 6-5, separation 20" ; easy double, can be seen with moderately low powers, even in 2-in. telescopes. Meteor Showers : — • Radiant. Date. R.A. 'Dec. Near to. T Leonis f( Draconis ii Ursae f Draconis Characteristics. Mar. 1-4 „ 14 .. 24 ., 28- h m. II 4 16 40 16 44 17 32 4- 4 4- 54 + 58^' 4- 62° Slow; bright. Swift. Swift. Rather swift. The Stars. — About the middle of the month at 9 p.m. the positions of the principal constellations are as follows : Disappearance. Reappearance. Date. Star's Name. Magni- tude. .Vngle from .^ngle from Mean Time. Mean Time. \. point \'ertex N. point Vertex March 22 22 22 . 22 . , 23 ■ , 25 e' Tauri 75 Tauri D.M. 4- B.A.C. 1391 1 1 T Tauri . . ij fi33 10.41 p.m. 10,35 P "1- II. I p m. 11.39 p.m. I ! . I p.m. 10. II p m. 223 324' 270 274 293 272" 184° 28.5 232 238 252'' 236 Moon's Age. \(< If) ifi 17 16 15 The Planets. — ^lercury is in superior conjunction with the Sun on the 26th, and throughout the month is too near the Sun for observation. Venus is an inconspicucus morning star during the month ; also, as she only precedes sunrise by about an hour, she is badly placed for observation, and is becom- ing more unfavourably situated as she is approaching conjunction with the Sun. Mars sets about 2 hours after the Sun on the ist, and about i^ hours on the 31st ; on account of his small angular diameter, he is an insignificant object in the western sky shortly after sunset. Jupiter is in conjunction with the Sun on the 27th, and therefore is only visible during the early part of the month after sunset. Ze.mth . No bright constellations in the zenith. South . Cancer and Hydra on the meridian ; Gemini high up, Procyon and Siriiis, all a litlle to the \y. Orion is to the S.W., and Leo (AVi';////s) to the S.E. high-up. West . Taurus, Aries near setting, Auriga {CapcUa) high up. To the N.W. Perseus, also Andromeda low down. East . N'irgo (Spied rising), Bootes (Anttirus). To the N.L. I'rsa .Major liigh up, (^orcjna, Her- cules, and Vega low down. North . /Wfov's ; to the right, Ursa Minor, Draco; below, Cygnus, Cepheus ; to the left, Cassiopeia. Minima of Algol inay be observed on the i'')th at o h. 7 m. a.m., i8th at 8.56 p.m., and 21st at 5.45 p.m. 40 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. A Photographic Atlas of the Moorv. VoLiMi; LI. of the Annals of the Harvard College Observa- tory is devoted to a photographic atlas of the Moon. This marks an epoch in selenography, not only because it is the first complete photographic atlas of the Moon yet pulilished, but because every part of the Moon is represented under five different conditions of illumination — sunrise, morning, noon, evening, and sunset. This fivefold presentation is of the greatest importance to the selenographical observer, as the change in appearance of most of the lunar formations during the course of the lunar day is so great that a photograph taken at one time becomes almost unrecognisable if compared with the Moon at another. It constitutes a record in another particular, namely, that the entire series of photographs were taken within the short period of seven months. Yet a third feature of the atlas lies in that this was the first time that a long focus telescope has been successfully employed in this department of astronomy. Such telescopes ha\e been em- ployed with success upon the corona in recent eclipses, but their application to the systematic record of the Moon was a new departure. This work is the result of one of those enterprises which the measureless energy of Prof. E. C. Pickering, and the corre- sponding munificence of the American public, have brought to completion within the last few years. An expedition under Prof. \V. H. Pickering, who has had much experience of the superb observing conditions both of .-Xrequipa and Arizona, was sent out from Har\ard College to the Island of Jamaica, and reported so satisfactorily on the " seeing," that at the end of 1900 he took out there a photographic O.G. of i^-inches aperture, and 135 ft. 4 in. focal length. This was set up at Mandeville, 20M0 feet abo\e the sea level, and used as a fixed telescope in conjunction with a heliostat. The seeing did not prove to be quite equal to expectation, and a yet more serious drawback was experienced in the want of flatness of the heliostat mirror. In most cases, therefore, the aperture of the photographic telescope had to be diminished to 6 inches, and the exposures lengthened accordingly. From the photographs taken by the expedition, 80 were selected, each y in., by 4 in., to form the complete lunar atlas, the Moon being divided for the purpose into sixteen different regions, each shown, as noted above, under fi\e different con- ditions of illumination. The parallels and meridians were laid down on a photograph of the full Moon, taken on 1901, August 21), the positions derived by Franz from measures of five negatives of the full Moon take'n at the Lick Observatory being taken as standards. Professor Franz's positions are undoul)tedly the most accurate yet published, and Professor Pickering devotes the last chapter of his book to an inquiry as to whether the altitude of a lunar mountain can be deduced from the discordances between its apparent co-ordinates on the lunar surface, as measured under different conditions of libration. The result, howe\er, is not very encouraging, the displacement to be measured being very nearly of the same order as the errors of observation, as Mr. S. A. Saunder has recently pointed out," and a far more extensive series of me.isures than any yet published are required in order to satisfactorily solve the question of lunar altitudes. The third chapter is devoted to the consideration of lunar change ; the cases of Eratosthenes, Pliniiis, and Pallas being lightly alhided to, whilst Linne, Plato, and Messier, with its companion Messier A. are treated with considerable detail. The enlarge- ments of Plato and Messier, especially the former, by no means justify Professor Pickering's claim that " these are the first photographs published, so far as I am aware, showing the details of the floor so plainly th.it they may l>e clearly distinguished." They are certainly not equal to the photographs of Plato in MM. Loewy and Puiseux's .Atlas. Another point on which Professor Pickering lays himself open to some criticism is the uncompromising way in which he habitually speaks of bright spots on the Moon being "snow," or "hoar frost," or " ice " • Observatory, iyo.|, Fobni.iry, p. y6. whilst dark spots are often as unhesitatingly described as ■• patches of vegetation." While not wishing to ignore the very considerable amount of evidence which Professor Pickering has elsewhere presented in favour of these, his views, they cannot yet be regarded as more than mere opinions, and it is hardly legitimate for him to express himself as if they were altogether beyond challenge. " Ann.'ils of the Astronomical Observatory of Harvard College," Vol. LL, a Photogr.iphic Atlas of the Moon, by William H. Pickering, Cambridge, Mass. Published by the Observatory, 1903. La>.rge v. Small Telescopes on Planets. To THK Editors ok " Knowledge." Sirs. — I was much interested in Mr. A. Stanley Williams's letter in the current number of " Knowledge." No doubt there is reason in his suggestion. But to my mind there is a much stronger reason for the greater relative defining power of small telescopes when used on planets over their perform- ance on double stars, which seems to be generally overlooked. ( )n double stars, I Iielieve. the rule of 4-56 seconds of arc divided by the aperture is generally accepted as the limit of the telescope's di\'iding power, and this agrees very well with theory. But it only holds good when the objects to be sepa- rated are sufiiciently bright to cause strong interference effects. Now the details on a planet are seen against a back- ground nearly as bright, and except at the edges the contrast is ^•ery feeble, so interference phenomena .are less appreciable. Therefore I hold that the 4-56 seconds-over-aperture rule does not apply. Mr. .\. Stanley Williams, in his first paragraph, also seems to imply a doubt of ordinary rules holding for lari^c areas, but I maintain that small telescopes will separate details on a planet very much closer than the above rule would allow. And so would, and sometimes does, a comparatively large aperture, but the magnification needed to tone down the light to utilize the larger aperture needs better atmospheric conditions, so that it is comparatively rarely that such aper- tures can be used with full effect. If we take 40 diameters to the inch of aperture as about the best ratio for viewing, say. Mars, one will on most nights find the seeing good enough to use the 120 needed by a 3-inch. But apply that rule to the 40-inch Verkes, and how often can a power of 1600 be employed to advantage ? A few years ago I made some experiments to test the sepa- rating power of I inch of aperture directed to black spots on white paper. I found that i inch would divide dots separated not more than i second of arc. and lines 07 second apart ; and that it would show a single black line o'S second in width, which was, of course, separating white areas divided by that amount only. I think these experiments, which can readily be repeated by anyone who wishes, show that when interference effects are negligible, one may expect a telescope to go far beyond the usually accepted limits. But if more were needed, Mr. and Mrs. Maunder have supplied it in the paper published last July in the B.A.-A. Journal alluded to by Mr. Williams in his letter to " Knowledge." There they show that a black line on unglazcd paper was seen sharply defined with the unaided eye under an angle of only 2'S seconds of arc. Taking the pupil of the eye when fully dilated at the extreme of one quarter of an inch, this is equivalent to 07 second of arc for i inch, which agrees well with my own experiments detailed above, though I consider it much more noteworthy, as the retina is composed of hexa- gons that at the nodal point of the lens system 01 the eye subtend an angle of about 23 seconds of arc, and th.at such a coarse structure should show a line only 2'8 seconds wide as sharply defined seems to bear out what Mr. Maunder says in his last paragraph, that : " A straight line is that which gives the least total excitement in order to produce an appreciable impression, and therefore the smallest appreciable impression oroduces the eff'ect of a straight line." H. W.\KE. Whiteha\en, January 11, 1904. Mar., 1904.] KNOWLEDGE & SCIEXTIEIC NEWS. 41 ASTRONOMICAL. Mr. Denning's Observa.tions of Mars in 1903. In the Astroiu'iiiisilw S'liiliiichten, No. 3426, Mr. F. W. Demiiiig gives the main results of his observation of Mars with a lo-inch reflector, in the Spring of 1903. The powers that he used ranged from 252 to 4S8. but the one most commonly employed was 312. He noted that occasionally there were decided changes in the visible appearance of certain markings, and these changes were obviously not due, either to uncertain seeing, or to the varying inclination of Mars, but, in the observer's opinion, to local vagaries in the Martian atmosphere. Thus, on May 6 and 7, he saw a white band dividing the canal Nilus, not seen on March 31 or April 2, and not shown on the charts, .\gain, on May 21. the northern region of the Syrtis Major was very dark, with a white cloud on its southern edge, but on May 23 and 24 the whole Syrtis Major was very faint, as if veiled by the cloud spreading northwards. As regards the " canals," Mr. Denning says : " ,\ large number of irregular dusky streaks ^canals), different in tone and direction, were observed. Some of these were very distinct, as, for example, Nilosyrtis, Protonilus, Indus, Ganges. Cerberus, Casius, &c., while others, as Phison, Euphrates, Gehon, were feeble or extremely faint and delicate. Many of them were knotted or strongly condensed in places, and particularly so at those points where either a junction or intersection of two of them occurred." Mr. Denning considers these streaks as certainly objective. He says that they were single, though in a few instances two of them w-ere placed tolerably near to- gether, running in appro.ximately parallel directions. He is emphatic that the " prolific system of double canals delineated by some observers had no existence " during the period of observation, as far as his eye and telescope could determine. Comparing these recent observations with those made in February, i.S6g, Mr. Denning deduces from I2,ij6 rotations of Mars, the value 24 h. 37 m. 22-7 s. for the rotation period. The Double Carvals of Ma.rs. Mr. Lowell, in Bulletin No. 5 of bis Observatory, gives evidence against the hypothesis that the gemination of the Martian canals is an interference effect. If it were so, the width between the two components of a double canal should vary inversely as the aperture. To test this, Mr, Lowell ob- served a number of double canals with the full aperture of his telescope ^24 inches), and then with that aperture reduced to 18, 12, and 6 inches. His measures of the drawings made under these several conditions showed that the apparent angular separation did not increase as the aperture was diminished ; that the separation was invariable within the limits of observation for any particular canal, but differed for different canals, bearing no relation to the width of an inter- ference pair of lines. Mr. Lowell's ObservaLtions of Ven\js in 1903. In Bulletin No. 6, Mr. Lowell classes the markings to be made out upon Venus under two heads. The first includes the collar round the south pole and the two spots on it, and the nicks inward from the terminator. Of these Mr. Lowell states he has ahvaysbeen certain, and "they alone are sufficient to show that the planet's rotation is an affair of about 225 days." The second class include the long shadings from the centre of the disc to the terminator, and of these, also, Mr. Lowell asserts " the objectiveness beyond the possibility of illusion." It will be seen that in this assertion Mr. Lowell is withdrawing his withdrawal of these markings which he pub- lished some eighteen months ago in tlir Aslivnoniisclti' Xiichrichltii. No. 3.S23. Mr. Liiwell furtluT adds that these streaks "bear no resemblance whatever to the ' canals '. of Mars, They are faint streaks or spots. . . . Tlu-v .ire not of even width, are not dark, and shai^iicul,^ .^ , . I'urllier- more, they are of a much higher order ortlill^iMtv c;l'vul(i»jj,s the conditions of visibilitv arc such as to sliilWajo ohsersi-r iTuT 'canals' of Mars with ease, ^i.^o saowajo^kse . aiuty, it wcreliSfTess to attempt this much harder plaiic*'.* Vjl-!ijt'il6^i^|}37s,WW' Lowuli Bulletin ch- la Socictc'^:\str,mnn,,,,ur^}»l l-i>mflU: etle^ ly wrote in the " Lcs configurations out tonjours dJiHrt ■^ en veritc que celles de la Lune. ' In for December, 1S96, lie wrote ; " The markiii,L;r. .nr iHuiniisi and well defined ; their contours standing out sharply against the lighter parts of the disc. . . . The seeing must l)e dis- tinctly bad to have the more prominent among them not discer- nible." This would seem to show that the definition at Flagstaff. Arizona, has changed seriously for tiie worse in the last seven years, whilst a comparison of the drawings of Venus, given in ttie Bulletin, with those of M.ars, such as in I'opitli::- .Istroitiiiny for y\pril. iiS()5, would not lead to the conclusion that there was any essential difference lietwcen tlie streaks on the two planets. Calcium and Hydrogen Floccxili. A memoir of quite exceptional interest is given on the subject by Professor G. F. Hale and Mr. Ellerman in Volum. III., Part I., of the Puhlutilioiis vf the Yirkcs Observatory Its subject is the minuter study of the surface of the sun by means of the spectroheliograph. The first point brought out is the essentially granular structure of the calcium fiocculi, the entire surface of the sun showing a fine mottling when photographed on the l)right K-hne, The next point is the study of these calcium clouds at difi'i-rent levels, the result of the examination bringing out in a striking manner the way in which the calcium bright clouds expand as they rise higher. The detection of the dark hydrogen fiocculi is another feature, and the fact that they often correspond, though not precisely, with the bright calcium fiocculi. Last of all the discovery of dark calcium fiocculi was established, and the necessity for further work with spectroheliographs of much higher disper- sion, and working upon larger images of the sun, is insisted upon. The memoir is illustrated by fifteen extremely fine photographic plates. The Nebulae. The Siiictccnth Century (iiui After for I'ebruar}' contains an article on " The Nel)ul;c," l>y the Rc\'. ICdnumd Ledger (iresham Lecturer on Astronomy, whicli summarises with admirafjle clearness and precision, the state of our present knowledge respecting these mysterious objects, and the con- nection with them of the stars. ZOOLOGICAL. At the meeting of the Geological .Society lield on January 20 Dr. A. Smith Woodward, of the British Museum, definitely determined th(^ .systematic position of the cretaceous fishes of the genus I'tycliudus, whose large, quadrangular, ridged crush- ing teeth are such familiar objects to collectors in the chalk- pits of the south-east of England. It has long been known that I'lychudus was an elasmobranch fish, and Dr. Woodward himself had some years ago pointed out the probability of its being a ray, or skate, rather than a shark. The truth of this conclusion is fully demonstrated by a specimen of the jaw cartilages recently discovered near Lewes, which serve to show that these fishes were allied to both the eagle-rays and the sting-rays, and probably, therefore, the ancestral type of bolli. A photograph was shown at the meeting of a splendid .\mcri- can specimen of the dentition of Ptychudus, witfi the teeth in their natural position, forming longitudinal rows. * ;;■- Fossil Birds- Certain fossil bird reiriains were discussed by Dr. C. W. .Andrews at the meeting of the Zoological Society held on 4^ KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. January ly. From Madagascar the speaker described a pelvis and thigh-hone of an ostrich-lil >j. ^-- X/ ? C^ y N^ y ^ y X ^ "^ ^^ ,y^y^ \ ^ ^ :^./ Fig. I. As the drawing of a cube to a Flatlander would seem to be only two squares on the same surface united by hnes also on that surface, so to us the above figure can at most only convey the idea of two cubes united by lines or perhaps by surfaces. We shall see this better if we draw the figure m perspective stereoscopically and examine the result m the stereoscope, when the two drawings will blend into one apparent solid. Here is such a stereoscopic diagram of the super-cube : — No, of Terminal Himensions Points. Joining Lines. Point Line S(|uare Cube Siij)er-rul)e n 16 Before we proceed to deal with the perspective repre- sentation of the last in this series of figures, the super-cube, it will be well to put ourselves back in imagination into .Abbott's Fldtland, and to consider what would be our b'latlander's impression of the perspective representation (jf the ( ube. '• Here is no third dimension," he would say ; ■' here are but two squares with lines joining them." lo us, who are accustomed mentally to connect such a figure with the similar retinal image which a solid cube forms in our eye, the concept of a third dimension is conveyed by association of ideas, but with the Flat- lander no such association of ideas would exist, because he would have had no experience of " thickness," him a Flatland ines. .Similarly, a full-face view of a cube would of course be to him simply a square, and in fact cannot be otherwise rendered on a flat surface. Now our relations to fourth-dimensional diagrams must be analogous. It is possible that we miglit make a pictorial rendering of a super-cube on paper, which to a being with senses capable of appreciating fourth-dimen- sional space would be suggestive of a fourth-dimensional super-solid, but to us, with no association of ideas to aid us, the figure must not be expected to afford a representa- experience and the figure would remain for one — two squares joined by four " Fig. 2. This slide, when seen in the stereoscope, shows us a peculiar looking figure, apparently three-dimensional. Now just is the perspective drawing of the cube suggests one tliree-dimensional figure to us but to the Flatlander a pair of united squares, so the above stereogram repre- sents a pair of united solids to us, but to beings with fourth-dimensional perception it might convey the notion of one super solid. It becomes e\'ident, therefore, that while our senses are (as at present) limited to three dimensions, we cannot ex- pect in the way thus far indicated to get any nearer to a concept of the super-cube. \'et there remains an experiment which carries us just a step further, and brings us to the \'ery verge of a solu- tion of our problem. Before we make this experiment it will -again elucidate the matter if once more we imagine ourselves for the moment in Flatland. There the drawing of a cube directly facing us would, as we have seen, be only one square, or more strictly one square exactly behind another. To the Flatlander, who does not know what " behind " means, it would be as though the two squares occupied the same space at the same time. Now the analogy from this is obvious, for in the same way under similar < ircumstances the super-cube of fourth- Mar., 1904.] KNOWLEDGE & SCIENTIFIC NEWS. 47 dimensional perception would to our perception seem like two cubes occupying the same space at the same time. They would really represent two separated rubes, but sejjarated in a direction neither up nor down, nor side- ways, nor cross-ways — in a direction of which we, with our three-dimensional conceptions, have no coj^nizance, just as the I'latlander had no cognizance of the meaning of a square being " behind " another square. The ()erspecti\e view of the cube when not seen full face would show tlie Flatlander the two squares only partially occupying the same space at the same time. In like manner we may put it that the super-cube, if presented to us broadside, would look like two cubes occupying the same space at the same time, while in other positions the two cubes would only partially occupy the same part of space. Now of this we can get some sort of representation by an interesting experiment with the stereoscope. Just as two flat drawings will give a representation of solidity when appropriately drawn and placed in that instrument, so two solids viewed through it will give some sort of idea of the super-solid. The experiment is striking and remarkable. Place in the centre of the field on each side in a stereoscope a solid cube. On looking through the instrument the two combine, and one cube is apparently seen. Now while looking at this one cube move slightly either of the culies as it lies in the stereoscope, and it w-ill be seen that our apparent one cube was composed of two occupying the same space at the same time. With the movement of one cube it is seen to pass partly out of the other, and we have an impression as to our super-solid exactly the counterpart of the Flatlander's impression of the cube as shown to him in the perspective drawing, first full face (the two squares occupying the same space and appearing as one) and then a more side view in which the two squares only partially occupy the same space. Using a cube on one side in the stereoscope and a ball of approximately the same size on the other the effect is still better seen, and without moving either the strange spectacle is revealed of a sphere and a cube occupying together the same part of space. The experiment affords, of course, but a suggestion of the fourth dimension, yet taken for what it is worth that suggestion is pregnant and of no small interest. Conducted by F. Shillington Scales, f.r.m.s. Microscopical Materia.1. By the kindnoss of Mr. \V. S. Rogers, of I'pper W'arling- ham, I was able la.st month to offer to the microscopical readers of " Knowledgk anij Scikntific Nkws" some "Comfrey" leaves (Symphytum ojjkuiale), which show well the beautiful basesof the leaf hairs. Mr. Rogers states that the appearance referred to is not seen in the leaves when fresh or when dried underpressure, but would seem to be brought into prominence by the blackening of the leaves when they lie fermenting on the ground in autumn. He adds that the material is intract- able to handle, the dried leaf being brittle and inclined to curl, and he has therefore punched them into '^ inch circles. They should, of course, be mounted as opaque objects. I regret that by a printer's oversight this notice was omitted last month, whilst the coupon was omitted the month before, thus causing unnecessary trouble to my many correspondents. Preserving Specimens of Orthoptera. A recent number ol tlir American J fin mil c/ .IpplicJ Mtcioscopy contains some interesting suggestions for preserving specimens of Orthoptera. .'\s the writer says, (heir compara- tively large size, juicy bodies, when alive or just killr-d, lirittle- ness of limbs and antenii.e wlien dried, llieir pronencss to fading after death, and their liability lo the attacks of mould and nuisciun pests, all seem to conspire against their preser- v.itiou. The larger and more showy specimens are best known, and the smaller and less brightly coloured forms are either entirely unknown or ha\e come to the notice of the \ cry few specialists who have ventured into an .almost forsaken field. There is, therefore, a rich field for investigation for any microscopist who is in want of a fitting direction for his studies. Placing these insects in alcohol and other li(|iiid preserva- tives has, in fact, overcome the objection to the soft juicy bodies that so (juickly shrivel and liecome discoloured wlien treated by the ordinary means of pre.serving insects ; but il has the disadvantage of ijuickly effacing the many bright colours conunon to such large niuubers of them, and even changes miiuite structural characteristics, ,so as to render the insects difficult of recognition. It al.so adds greatly to the space taken up l)y the collection, and renders their trans- portation difficult. Still it is an effective preservative against insect pests, such as Dcnncstcs, Sec. Orthoptera can, however, be handled "taxidermically " — ('.f., stulTed much as birds, &c., are stuffed. Instead of throwing the insects into spirits, they should, when captured, be killed in the cyanide bottle. The specimen being then hold in the fingers and thumb of the left hand, with a fine, sharp-pointed pair of scissors open the .abdomen by cutting across the middle of the two basal segments on the lower side, then reverse and cut the opening a trifle larger by nearly severing the third segment. Then extract all the insides (intestines, crop, ovaries, &c.). along with the juices, using fine forceps for this purpose, and wipe out the inside with a small wad of cotton. This being done, the insect may be pinned into a box or wr.ipped in paper and packed away for future use. The "stuffing "is carried out as follows. Cut some raw cotton into short pieces, and fill up the insect through the opening made as above, using similar fine forceps and taking care not to stretch or distend the ,al)domen beyond its original dimensions. When the filling is completed draw the edges of the severed segments carefully together, and press the sides of the abdomen into sh.ape with the fingers. This can all be done, after a little pr.actice, in four or five minutes' time. It will be found that the insect will not decay or turn dark, the original colours will be almost entirely preserved, and there is but little danger of attack by museum pests, on of the mould which so frequently spoils objects which .ire long in drying. Mouldy specimens can often be saved by being pl.iced in a tin box between wet cloths or blotting p.ipers well sprinkled with dilute carbolic ,icid, and left for twenty-four hours to thirty-six hours, or until sufficiently soft not to break when h.indled. Then pour some alcohol into a dish, and .add to it about one-twenfieth as much liquid carbolic acid. With a camel-hair brush carefully clean the entir(^ insect, taking care to wash every portion with the niixttue of alcohol and acid. In arranging in the cabinet the suggestion is made that nuich sp.ace can be economised by directing long antennas backwards along the sides of the insect, and by folding and crossing the legs beneath the body. In the Saltatoria. or jumping forms, the pin should be inserted near the back edge of the pronotum, a little to one side of the middle, .and direct- ing it to the rear, letting it pass downward through the meso- thorax, tliereliy tightly fastening together the two sections of the body. In the other forms, Bliillnidfd, Mmtlniiltn. and Plmsiiinuic-ii, the pin should be inserted l)ehind the pronotiuu through th(t middle of the body, taking care to select a solid portion for this purpose, without running the pin through the basal portion of any of the legs. The "Argus" Attachable Mechanical Stage. This stage was designed for use with the "Argus" micro- scope, noticed in the January issue of " Knowlkdgh," p.age 21, but it can be fitted to any ordinary microscope, being attached 48 KNOWLEDGE & SCIENTIFIC NEWS. [Mar., 1904. by means of a thumb screw only. It is decidedly original in design. .\ friction wheel, actuated by a single milled head, is in contact with a broad brass plate attached to the clips which hold the slide. A steel spring gives the necessary pressure, and the spindle bearing the friction wheel and milled head is movable on a vertical pin. A glance at the illustration will make the principle clear, and it will be seen that the stage S^^^j BOjI ,^■■1 T* travels readily m a \ertical or horizontal direction, or in any intermediate diagonal direction, according to the position in which the milled head is held whilst rotating. Check pins in- dicate the horizontal and vertical positions respectively. By this means not only are rectangular movements obtained, but any desired diagonal movement is obtained in addition. The whole stage works with great smoothness and sensitiveness. The mechanism is entirely on one side of the stage, so that none of the working parts are in the way of the instrument. Quekett Microscopical Club. The 409th ordinary meeting of the Club was held on Decem- ber is. at 20, Hanover Square, W., the Vice-President, A, D, Michael, Esq., F.L,S., in the chair, A most interesting col- lection of diffraction gratings of various kinds was on view, and the exhibitor, Mr, Julius Rheinberg, F,R.M.S,, briefly described them and pointed out the curious optical effects obtainable. Among the most interesting of the exhibits was a reflecting diffraction grating on plate glass, silvered on the grating side, ruled by Colonel L. Paxton, of Chichester, It consisted of intersecting systems of circles. Each system consisted of a series of excentric circles, the locus of their centres being an intermediate circle. When exposed hori- zontally below a flame, an observer stationed a few yards away could see four intersecting rings of light stereoscopically projected several inches in front of the mirror, whilst a similar system of rings was seen several inches behind the mirror, Mr, Rheinberg then read a paper ''On an Overlooked Point concerning the Resolving Power of the Microscope." It dealt with a discovery made from the theoretical standpoint some years ago by Dr. Johnstone Stoney, F,R.S,, which had only recentlv been practically demonstrated — viz., that an objective would resolve and separate two dots or Imes of a known distance apart, although unable, owing to its N,.\,, to resolve a series or band of dots or Hues at equal similar intervals. The experiment was practically demonstrated to the Club, a Grayson test plate of 15,000 lines to the inch being used for the purpose, with a Zeiss S mm, apochromat. and a 27 mm. compensating ocular. Mr. D. J. Scourfield, F.R.M,S,, then gave an epitome of the third part of his Synopsis of the British Fresh Water Entomo- straca. It dealt with the ( Jstracoda, of which we have about 62 species, nearly all widely distributed ; the Phyllopoda, of which there is only a single form now recorded, another form, .•l/j».s£((Hi-n/o>-;«/s,being apparently extinct: and the Branchiura, with two species, one lieing extremely rare. This was the con- cluding portion of Mr, Scourfield's valuable series of papers on the British Entomostraca, The 410th ordinary meeting of the Club was held on January- 15, the President, Mr,-(ieorge Massie, F,L,S,, in the chair. There was a large attendance, Mr, C, Rousse- let, F.K.M.S., read a paper ou '■.\ New Freshwater Poh'zoon from Rhodesia," which was illustrated both by a diagram and by specimens shown under the microscope. The polyzoon referred to differs in many ways from all other known species, and is especially characterised by the production of elliptical statoblasts having five spines at each end, the spines being armed with minute hooks, Mr. J. T. Holder exhibited an interesting series of lantern slides of Foraminifera from photographs taken by himself. The specimens varied much in size, some of the large groups being J inch in diameter, and containing several hundred selected specimens from -jifj to i inch in diameter. .\ 4-inch objective was used, and in spite of the difference in focal plane the photograph was quite successful. Other photographs were taken with 2-inch and i-inch objectives. The exposures varied from a few seconds to three quarters of an hour, an isochro- matic screen being invariably used. The camera and ap- paratus emploved were also shown on the screen. Mr. Earland ga% e a brief description of the slides, and con- gratulated Mr, Holder on his success, and especially on the way in which the glassy transparency, which was one of the most beautiful features of the hyaline Foraminifera, had been reproduced in the photographs. .'Attention was particularly drawn to Frondicutaria aluta from Cuba, found at the depth of 700 fathoms. The genus was now almost extinct, but was abundant in Secondary times. .\t present it was found in numbers in only two small areas in the world, each widely distant from the other, namely, the Caribbean Sea and the shores of New Guinea. .Attention w-as also called to the great difference in the form and structure of the specimens shown on the screen. This was due to the different methods of growth, which, in turn, w-as a result of the difference in size of the primordial chambers. It was a typical instance of dimor- phism, and the two specimens represented the megalospheric and microspheric types respectively. Two especially interest- ing slides were Polystomella craticiilata and Orhulina uiiii-ersa. In the first the foraminifer was show-n side by side with a cast of the animal's body, the cast being quite perfect, and exhibiting every detail of structure, the canal system and primordial chamber being sharply marked on the screen. In the slide of Orhulina iinivirsa some of the spherical details had been laid open in order to show the internal Globigerina shell. This was shown in various stages, from the perfect shell, attached by five spines to the inner surface of the sphere, and not distinguishable from a pelagic Globigerina, to the last disappearing chamberlet. The mystery of these internal chambers, which were only found in a small percentage of specimens, was unsolved ; but a theory had been invented to account for them. It was supposed that the pelagic Globigerina, in order to protect its delicate spinous shell from the action of the waves, formed a spherical shell outside it, and the internal shell being then of no further use was gradually absorbed ind disappeared. A number of photographs of rock-sections next exhibited showed Foramini- fera ill situ, and exemplified the important part played bv them in the structure of the earth, more important than all other animals put together. They were amongst the very earliest inhabitants of the earth, their remains being found as far back as the Lower Cambrian strata, and some of the genera, perhaps even species, found there were still in exis- tence. They formed enormous masses of limestone in carboni- ferous times, and the gault and chalk were largely composed of their remains. But they reached their greatest develop- ment in Tertiary times, when the famous Nummulitic and .\lveolina limestones were built up by them, the deposits stretching in an almost unbroken series across Europe and the western half of Asia, reaching a thickness in places of many thousand feet. Their modern representatives were both small and infrequent. In addition, a number of marine organisms, admirably pre- served, were shown under microscopes on behalf of Mr, H, J, Waddington, a former member of the Club, Royal Microscopic.\l Society, December 16, Dr. Henry Woodward. F,R,S,, President, in the chair. Mr. F, W, Watson Baker exhibited under microscopes an exceedingly complete and valuable series of slides, 16 in number, illustrating the development of an ascidian from the fertilization of the ovum to the larval stage. The slides were prepared by a gentle- man well known to many of the Fellows, who had been most successful in his management of marine aquaria. Dr. G. J. Hinde read a paper " On the Structure and .^.ffinities of the Genus Pomsphara." which was illustrated by diagrams, mounted slides under microscopes, and specimens, many col- lected by Dr, Hinde in his garden at Croydon, which had M/ 1904.] KNOWLEDGE .t SCIENTIFIC NEWS. 49 been weathered out of the chalk. — January 20, Annual Meeting the President, Dr. Henry Woodward, F.K.S., in the chair. The Curator, Mr. C. Kousselet, e.xhibited an old microscope by Plossl, of Vienna, which had been sent on approval. It has a folding tripod foot which carries a short column sur- mounted by a compass joint for inclining the instrument. To a hinged attachment of the compass jomt a triangular steel bar is fixed. On this bar slides a bracket, having a curved arm, to which the body of the microscope is secured. A rack is sunk into the base or b.ack of the triangular bar for the coarse adjustment, the pinion of which is contained in the sliding bracket. The stage, which is also carried by the triangular bar, has slow rectangular movements of very hniited extent. There is also a micrometer movement, right and left, for measuring objects, and a fine adjustment lor focussing. There are six object glasses which can be used separately or in various combinations of two or three glasses. Among the apparatus is a lenticular prism for illuminating opaque objects and two diaphragms for reducing the diameter ot the reflecting surface of tne mirror. The ballot for officers and Council for the ensuing year was then taken, and Dr. Dukinfield H. Scott, F.K.S., was elected President. The other business of the annual meeting having been disposed of. Dr. Henry Woodward, the retiring President, proceeded to give his annual address, taking as his subject " The Involution of Vertebrate Animals in Time." His paper was illustrated by diagrams, drawings, and slides, about So in number, shown upon the screen. A Novel Electric Traction System. In No. 2 of the EUktrotechnischer Anzcigcr E. Leuggenhager describes an electric railway traction system which is being developed at the present luoinent by a Swiss " Studiengesells- chaft," appointed for the purpose of finding out an electric railway system suitable for that country, which, on account of her dependency on the foreign coal market, evidently should endeavour to utilize her wealth in hydraulic power. Speeds, on the otuer hand, are limited there on account of the steep gradients, small curves, and numerous stoppages. The system in question uses steam locomotives hentai by electricity. Elec- tric heating, as is well known, will work with the highest possible ethciency, so that the total efficiency will mainly depend on the output of the mechanical part of the locomo- tive, being the steam-engine proper. Any coal steam loco- motive could readily be converted into an " electrothermical' ' locomotive by simply replacing the fire-box and boiling-tube of the boiler by a number of parallel electric heating-walls rumiing througnout the boiler and being co[nposed of two copper or iron sheets. The author suggests using in this con- nection the well-known Prometheus heating elements. The con- sumption of current would depend on the consumption of steam. Let the boiler be designed lor accommodating 4000 litres of water, which are to be brought within 3 hours from 10' up to about igo^ C, corresponding with a steam pressure of 50 kg. per sq. cm. In the case of an efficiency only as high as 90 per cent, the following data would be obtained : 4000 1. of water would require, in order to be brought to the above tempera- ture, 4000 X iSo = 720.000 kg. cal. ; i kg. cal. = 1275 eft. watt, hours, therefore 720-000 kg. cal. = about goo eii. kw. hours, or, distributing this amount over 3 hours = about 300 kw. A consumption of steam of 1000 kg. per hour would accordingly require a supply of current of about 225 kw. As regards the advantages inherent in theelectrothermic system, the resistance of the steam accumulator against current shocks should be mentioned. There is the further advantage of both direct and alternating currents being practicable in this con- nection, any desired combination being suitable. The mean efficiency of electrothermic locomotives, being about the same as that of an electromotive machine ot the same size, would be about 5o to 70 per cent., whereas the total efficiency of a railway system, on account of the more advantageous utiliza- tion of tne load, would be higher for the former. Further- more, the adoption of electrothermic service may take place gradually, being much easier than that of electromotive service, on account of the lower cost of the conversion and the easiness with which the personnel may be trained for the new service. A possible conversion of electrothermic into electromotive railway service would finally be readily made should the electromotive service in future be so improved as to become superior to the electrothermic system. — A.G. Geodetical Irvstrvirrvents. I'roiii Mr. James Hicks, of llatton Ganlen, we have rcceivcil a calaloguc ol the new types oi liaiul surveying instriuncnts designed and patented by Sir Howard (hubb. I-".K,S. 'iliese extremely ingenious and tisclul instruments were designed by the inventor primarily (or the use ol those wliose work in surveying required simple, portable, and easily compreliensible instruments lor rapid work, file principal advanl.ages common to all the instruments .ire tlie film surface of the glass, which is of a kind capable both of rellecting and transmittin.n a considerable portion of the light which lulls on It ; and the adoption of the collimator system for parallel- isiny ra\s. Hy the use ol the Keynolds-tjrubb film, light Irom two diflerent directions can be directed into tile eye of the oliscrver without recourse to the inconvenient old method which was known ;is "dividing the pupil." The collimator system of parallelising rays has also great atlvantages in convenience and simplicity of observation. Among the instruments to which these methods have been specially and advantageously applied are the small clino- meter and prismatic compass and a level. Mr. llicks also com- prises in liis catalogue of these new types ol hand surveying in- struments, an optical square fitted lor use with the naked eye, an attachment for a telescope, a graphonieter, and a pocket surveying instrument. REVIEWS OF BOOKS. Who's Who, ys. Od. (A.&C. Black), grows stouter every year, and now contains no fewer than 17,000 biographies. Its great usefulness is so well recognised that it need not be dilated upon. Some few of the biographies might, one would think, be curtailed, especially as regards " recreations," one of which, we note, reads " homely table games of cards, chess, Ijack- gammon, halma, cribb,age, &.c." Otherwise, the succinct ac- counts of the lives of every Englishman of any note are most complete, and just what one requires. Who's Who Year Book, is., is a small book containing the tables which were formerly incorporated in Who's Who, but which have been deleted from time to time to make room for the evcr-increasin.g number of biographies. These tables are most useful for reference, including as they do not only .such as are to be found in many other annuals, but also lists of Koyal Academicians, Bishops, Newspapers and Magazines, l^seudonyms and Pennames, Principal Schools (with number of pupils and cost), I'ellows of the Koyal Society, Societies, &.O., Chairs and Professorships, Heirs of Peers, iS;c. The Englishwoman's Year Book, 2s. 6d. (.'\. &. C. Black), " aims at giving some idea of the extent of women's work and interests, and some guidance to those who want to help their fellow-creatures, whether as individuals they live lives of which their own home is the centre, or take a wider view of their opportunities and responsibilities,'' and has a wonderful mass of useful information packed into its 350 pages. BOOKS RECEIVED. [I'he notice oj books in this column does not preclude the revieio of them at a later date). Studies in Hcterogenesis, by H. Charlton Bastian, M.A., .M.D.Lond., F.K.S. (Williams and Norgate, one vol.; price 31s. 6d.) .\ monumental work, illustrated with more than eight hundred micro-photographs, and summing up the whole number of instances of the apparent transformation of the substances of parent matrices into new forms of lite. The author examines the alternativ'C explanations of these pheno- mena— (i) That the resulting forms of life are due to the invasion and multiplication of parasites within what appear to be parent organisms ; (2) that the resulting forms of life are in reality heterogenetic products originating from the very substance of the organisms from which they proceed — - and gives his reasons for adopting, after prolonged and care- ful study, the second of these theorems. 50 KNOWLEDGE & SCIENTIFIC NEWS. [M AR., 1904. The Worship of the Dead, by Colonel J. Gamier. (Chapman and Hall, one vol.). Colonel J. Garnier.s work on "The Worship of the Dead" (Chapman and Halli deals with the origin and nature of Pagan idolatry and its bearing upon the early history of Egypt and Babylonia. The voluminous materials collected by previous writers on the subject are here set forth within a moderate compass and in a readable form. The book is profusely illustrated with interesting examples of the statues of ancient gods. Cassell's Popular Science (Cassell and Co.). edited by Ale.x- ander S. Gait, with contributions from T. C. Hepwort'h, Pro- fessor Bonnev. Frank Weedon, John Fraser. F.L.S., Wilfred Mark Webb. F.L.S., Dr. .\ndrew Wilson. Dr. Bernard Hol- lander, and William Ackroyd, F.I.C. The subjects range from radium to carnivorous plants, and from the transit of Venus of 1SS2 to the working dynamo. The articles, of which there are some sixty, are clearU- and well written, and in every respect justify the title under which they are collected. British Tyroglyphida, by Albert D. Michael. F.L.S., F.S.S., &c. Vol. II. (Printed for the Royal Society.) This volume contains the description, with plates, of the genera and species of the British Tyroglyphids. from the genus Chortoglyphus to the Tyroglyphus Wasmanni. .\ list of foreign species is added. The Old Testament and Historical Records, bv Theophilus Pinches. LL.D. lOne vol. Second Edition. S.P.C.K.l In the second edition of the " Old Testament in the Light of the Historical Records and Legends of Assyria and Babylonia,'' Dr. Pinches adds some exceedingly valuable and interesting matter on the Laws of Hammurak. together with a translation of the laws and notes on Delitzch's lectures on this subject. A School Geometry. Parts I.-V. By H. S. Hall, M.A.. and F. H. Stevens. M..\. (Macmillan. One vol. ; price 4s. 6d.) — This is a publication, in one volume, of a geometry for schools based on the recommendation of the Mathematical Associa- tion and on the new Cambridge syllabus. Descriptive Chemistrj-, by Lyman C. Newell. Ph.D. One vol.. with supplementary vol. of experiments. (London: D. C. Heath; price 4s. 6d. and is. 6d.i — Intended for teachers who wish to emphasise the facts, law-s. theories, and applica- tions of chemistry. The experiments have been prepared for limited laboratory facilities. ■^^ rf^> -^i ^^ ^*i CKess Problems. Owing to the great amount of matter which we have on hand we have felt it necessary to again postpone pubhshing the Chess Problems. We should be very glad to have the opinions of those interested in this subject as to the continuance or otherwise of the Chess Column. LAST YEAR'S WEATHER— MARCH, 1903. DISTRIBUTION OF MEAN TEMPERATURE. f RAINFALL. ♦•96 73 1^2 It / ■■■5S«( "'^^ AoeV. 3 86 V* 2 02 C^I30i 6-24.. «^ '♦e2» . 180 ... ,1 65 * S6»^_/-^ 9L, The general distribution all o>fr ' generally, but was rather deficient on the east coasts of England and the north-east coasts of Scotland. Over the western half of the Kingdom the excess was very large, the amount at manv stations being more than double the average. KDomledge & Selentifie flems A MONTI II A' JOURNAL OF SCIENCE. Vol. I. No. [new skrifs ] APRIL, 1904. E Entered at 1 Stationers' Hall.J SIXPENCE. > Contents and Notices. — See Page VII. The Protective Resemblance of Insects. By Percy Collins. The story of insect life has many phases of entrancing,' interest ; nor is this altogether surprising when we remember that the earth, the air, and the water are alike peopled by the vast army of the six-footed. These varied conditions of life have left their mark not only upon the habits and movements of insects, but upon their colour, their form, and their instinctive attitudes of repose. So that although insects are more diverse than any other natural group of living creatures, the explanation is simple; they are and have been subjected to almost every condition under which life is known to be possible. Thus, to the entomologist, every difference of form, colour, or attitude seems worthy of serious investigation. He realises that an unusual tint or a quaint pattern carries with it a definite meaning — that it is in some way linked to the ancestral history of its possessor. Often enough this meaning is mysterious. But occasionally the colours and form of an insect, or of a group of insects, can be explained as the direct outcome of certain known in- fluences. Not infrequently such interpretations reveal the fact that the shape or colour of an insect, or both in combination, are mainly responsible for its well being. The creature's peculiar appearance either mystifies its enemies or enables it to approach unobserved the smaller insects upon which it preys. The whole subject, to which the general term " mimicry " is commonly applied, constitutes one of the most fascinating phases of entomo- logical study. The simple protective resemblance of an insect may be either general or special. That is to say, the protec- tion may originate in the mere likeness of an insect's sur- face colouring to that of its customary surroundings, or it may consist in an actual reproduction in both form and colour of a certain object with which the creature is commonly associated tliroughout its life. Instances of general protective resemblance must be familiar to observers in all countries. The numerous moths which are accustomed to rest for hours together upon rocks or tree trunks are oft-cited examples. Con- spicuous among tliem is the whole genus Calocala, the various species of which are widely distributed in the Pakvarctic region and elsewhere. These moths have brightly coloured hind wings, the usual tint — which has given to them their popular title of " Red-underwings " — being some shade of crimson or pink. When they are on the wing they are sufficiently conspicuous, and are liable to be snapped up by a hungry bird. But when at rest upon a tree trunk in tlieir customary attitude of repose, the soft grey or brown colour of their fore wings produces a general effect so well in keeping with the Catocala sp, Japan. Catocala sp. Japan. At rnst on bark. rough surface of the bark, that they are' extremely diffi- cult to detect. Their colour pattern alone constitutes a most effectual hiding. KNOWLEDGE & SCIENTIFIC NEWS. [April, 1904. The same may be said of countless other moths, especi- ally of the great Noctiia group ; and it is interesting to trace how closely the colour of the fore wings in a given species corresponds to its habitual resting place. The appearance of all kinds of bark, of moss}' twigs and of lichen-covered rocks is faithfully reproduced ; nor is it necessary to search beyond the moths of our own islands for striking examples. Many butterflies, especially of the great group .Vvw;/'/ia- liiuv, possess — in the tints of their under side— a general resemblance to the ground upon which they habitually Hamanumida dedalus. Africa. settle. Moreover, many species seem to have acquired the trick of inclining their folded wings out of the perpendicular, by this means covering, or minimising, their own shadow, as well as bringing the protectively coloured underside into more prominent view. This habit may be observed in many of our common " brown " butterflies — for instance, in Pyrarga mcgaera and in Satyvus semde. In connection with this apparently acquired aid to protected resemblance, the habits of Hamanumida dcdalus, an African butterfly, are exceedingly interesting. It is authoritatively stated that this insect rests in West Africa with its wings folded over its back after the soil, is exposed to view. In South Africa, on the other hand, the same insect sits with its wingsexpanded, show- ing the brownish grey upper side which harmonises with the colours of the rocks in that region. Many of the Coleoptcra, from their colour, are almost indistinguishable when resting upon lichen-incrusted bark. The accompanying photograph of a Longuorn from Bhutan admirably illustrates this phase of general protec- tive resemblance. Although the insects are in full view, the casual glance quite fails to detect their presence. This surprising result is largely gained by the manner in which the colour is, as it were, cut up into dark and light patches. This is particularly noticeable in the long antenna", the sharp outline of which is entirely effaced from their being coloured in alternate lengths of black and grey. Turning from general to special protective resemblance, we find a number of extremely interesting and remark- able examples, especially among exotic insects. The butterflies of the genus Kallima — " leaf butterflies," as they are popularly called — bear striking testimony to the Hamanumida dedalus. (Underside.) .Mrica. common habit of butterflies, in which position its tawny under surface, which agrees with the general tone of the Apallmna ducalis. Male and Female. Bhutan. On Lichenous Bark. powers of natural selection. When flying in the full sunlight, their wings flash with colour, but directly they come to rest upon a twig they are, to all appearances, brown and withered leaves. This sudden transformation is made possible by the tinting of the under surface of the wings, and by the curiously erect attitude which the insect is able to assume — its wings drawn upright over the back and its head and antennae concealed between their anterior margins. When we consider the mar- vellous accuracy of the colour imitation, the uncommon shape of the insect's wings and its unusual pose, the leaf butterfly must still be ranked as one of the most amazing instances of protective resemblance yet recorded, not- withstanding the many marvels which have been brought to our notice within recent years. The larvae of moths grouped under the title Geome- tridcT usually bear a curiously accurate resemblance to liitle twigs or sticks, both in shape and in their brown April 1904] KNOWLEDGE & SCIENTIFIC NEWS. 53 Kallima niachfs. India. Two Specinjens at rest among leaves. or grey colouring. Moreover, this deception is materially heightened by the unique attitude of repose obtaining among these caterpillars, which differ from most lepidop- terous larva; in possessing only two instead of five pairs of pro-legs. These are placed at the extreme posterior riul 111 the body, while the three pairs of true legs at the other extremity arc usually exceedingly diniinuti\e. 'l"he perfect stick-likeness is gained in the following manner. The caterpillars of the GconulridfC usually feed at night. When daylight comes, or under Ihe stimulus of alarm, they take a tirm hold upon ilic iwig with their four pro- legs and stretch out their cylindrit al body stiff and straight at an acute angle. In this position they are capable of remaining, absolutely motionless, for liours together. But to counteract the terrible strain which the attitude would impose u])()ii the body of the caterpillar, each usually spins a strong, though practically invisible silken thread from its mouth to the twig fin which it rests. A family of insects remarkable above all otliers for the almost universal protective resemblance of its members is the Phasmida. In order to understand these creatures, which are numerous in all tropical countries, it is neces- sary to know something of their habits, llnlike their Three Caterpillars ol Hemerophila abruptaria. l-.iifilaml ClitumnuA Sundaicus. Stick-hke I'h.isiiiiil, near relatives, the Mantidce or " praying insects," which are voracious insect eaters, the Phasmida' are exclusive vegetarians, feeding greedily upon the leaves of the plants which form their resting places. In movement, Phasmids are extremely sluggish, and many of the species — being apterous or possessing, at most, only rudimentary wings — are incapable of flight. Thus, they are much exposed to the attacks of birds and other insectivorous creatures — have been so, in all probability, forages past. This per- secution might be supposed to foster any variation in shape or colour likely to be of protective value. And, as a matter of fact, the whole of the Phasmidce, almost with- out exception, have undergone striking modifications in the direction of special resemblance. As a rule, the bodies of these insects have become greatly lengthened, while the legs are long and slender. Those known popularly as " walking sticks," of which the Cliluinnus sundaicus shown in the accompanying photo- 54 KNOWLEDGE & SCIENTIFIC NEWS. [April, 1904. graph is a good example, are generally of a uniform brown tint. Many of the species have curious knotty protuberances, or even prickles, upon their bodies and legs, this, of course, adding much to the stick-like aspect winged Phasmld, showing two portions into which each win^^ is divided. of the insect. After examining a dried specimen of a "stick" Phasmid, one does not need the assurance of foreign collectors to believe that these creatures are prac- tically invisible when at home among the branches of their native shrubs. Winded Phasmid. at rest among grass blades. Other Phasmidce — fairy-like creatures with exquisitely coloured wings — resemble grass rather than twigs when at rest. Their bodies, legs, antennae, indeed every part of them, with the exception of certain portions of the wing area, is green. Their first pair of wings is rudi- mentary ; but their hind wings are ample, gauzy, and fan-like in their manner of folding. A narrow strip at the anterior margin of each wing is thickened and green in colour, contrasting strangely with the gauzy area, which is usually bright pink. Under this narrow cover, the whole of the bright, flimsy portion of the wing is packed away when the insect comes to rest. And so closely are the wings folded that the casual observer imagines the creature to be apterous. It is, indeed, the exact counterpart, of a crumpled or slightly-thickened grass blade, while its legs and antenna;- are too slender to attract much notice. Phyllium sp. Female. Ceylon. Perhaps the most remarkable genus of the Phinmid^73, which took place at the ripe age of eighty-eight, and he was buried in the ante-chapel of Trinity College. Finally, let these words of his further proclaim the man : " My labour is its own reward. It gave me health, and led me into scenes of grandeur which taught me to feel in my heart that I was among the works of the great Creator." Telegraphically Trans- mitted PhotogrsLphs. By Dr. Alfred Grauenw it/. Many attempts ha\e been made to transmit handwriting, photographs, drawings, (S;c.. by telegraphic means, and the more or less successful solutions which have been suggested for this problem of late years are numerous. Selenium cells, as shown by Herr Ruhmer's successful experiments in the field of wireless telephony, give a ready means of detecting and transmitting by telephone even very slight fluctuations in the intensity of a source of illumination, and afford means ol con- verting these fluctuations into oscillations of an electric current. If a hght ray and a selenium cell be simultaneously drawn along over opposite sides of a photographic plate, llie different shades of the various portions of the plate will result in con- tinuous oscillations of the current being produced in the cir- cuit of the cell This is a common feature with all the sending devices used in the instruments of this class. The current oscillations are made to act on the receiving apparatus, which will reconvert them in turn into fluctuations of light. The design of the receiving apparatus has hitherto been the weak point with all these systems, because the electric currents transmitted are so Aery small. Hut a satisfactory solution of the difficulties so far met with seems to be aflorded apparatus of I'rofessor Arthur Korn. presented before the French Academy by the teleoptical ^Iunich, as recent! v of Sciences. While engaged in investigating the radiations given off by the electrodes of a tube exhausted to a pressure ranging be- tween 0-2 and 2 mill, as Hertzian vibrations were applied to the electrodes. Professor Korn noticed the extreme seubitive- ness with which these radiations would react on small altera- tions in the circuit. This sensitiveness suggested a possible utilisation of those radiations which were photographically most efficient, in connection with a method of electrical tele- photography. The apparatus, based on the above principle, is shown in fig. 1. The photographic film a uf the receiver rotates in front of a small window c (0-25 mm x 0-25 mm) in an exhausted tube /), like a roller, in front of the \ibratiug membrane ot a phono- graph. The surface of the tube is coated with black paper and tin-toil, lea-i-ing only the window. By means of high fre- quency currents (Tesla currents), luminous radiations may be produced inside the tube, and these, after passing through the small window, will make photographic impressions on the sen- sitive film. The latter is moved synchronously with the image- holder A of thesending-apparatus(afilm bearing the photograph to be transmitted wound on a glass cylinder), which is traversed by a very thin beam of light B C D while passing, line per line, before a selenium cell D placed inside the cylinder. .According to the different shades in the photograph transmitted, thesele- SoKlif of Light 'SjjtA I Gxj^^acciXXf Fig. nium will receive more or less light, while an electric current, passing through the selenium D and the telegraphic wire F up to the recei\'ing apparatus, will undergo corresponding varia- tions of intensity, thereby regulating the intensity of the radiations of the receiving tube. This is provided for in the following way: The active electrode e of the tube being con- nected to one of the poles />, of the secondary coil of a Tesla apparatus, by inserting fields of sparks formed by the points Original Photograph. Transmitted Photograph. ^ .» nil, uij, of a galvaifometer needle / and two fixed points", fj, L, the intensity of the radiations given off by the tube will be more or less great, according to the distances nij fj and m, and (2, which are variable along w-ith the transmitted currents passing through the galvanometer i'. By the use of this arrangement, a means is afforded of making the intensity of the radiations of the receiving tube correspond with the in- tensity of the light striking the selenium of the sending- apparatus, thus reproducing line per line of the original photo- graph. April, 1904.1 Tlu KNOWLEDGl*: \- SCIENTIFIC NEWS. 57 well. i.ij lui- Litciiii may. as wen. serve as a telautographical recciviiif;-apparatu:s. i.e. an apparatus for re- producing handwriting, drawinsr. &c.. at groat distances. In this case, only sonic ver\' slight alterations will liave to be made, and .i BakewcllCaselli transmitter used. The speed attained is relatively very high. It has been loinid possible to reproduce from tueiitv to fortv words in the Orig:inal Photograph. original handwriting iu the course of \.hu-e minutes, and in th< case of shorthand much higher speeds may be arrived .it. The transmis.sion of photographs, of course, is slower, princi- pally on account of a certain inertia of the selenium. Tin- progress lately made in connection with the construction of seleniimi cells', however, makes much higher speeds very prob- able. The time at present required for telepholographing a portrait is about half-an-hour. Transmitled Photograpli. Figs. 2 and 3 show the telegraphic reproduction of a photo- graph and a telautographic specimen respectively. The in- ventor wishes us to state that part of the imperfections of tlie photo, especially the stripes, is due to the e.xperiments having been made in the Physical Laborator\- of the Munich Univer- sity, where the pressure of the battery and, accordingly, the intensity of the source of light, would undergo frequent fluctua- tions. Modern Views of CKemistry. By II. J. II. l-E.MON, l-'.K.S. In our last coiiunimiiation \\c indicated \er\ Ijrieth', in outline, the nature ol the ionic-dissuciatiiui Ii\ polhesis, and mentioned Slime of the expeiiniental fads upon wbicli it is basi'd ; we propose now to ^i\e a few illustr.il ions oi the manner in, which the lupothesis li;is been applied to the explanatioir or inlerpret.ilioii ol sonic well known chemical and physical laiis. \\ hat is an ;u'id r' l'!\ei\one who is al all ai(|uamled with the cleinenlar\ huts ol cheniislrx has a lairh clear conception in his own mind what the term implies, but attempts to frame an exact definition .are not always satisfactory. If an acid is " an\' liydroi^eii compound which can exclKuii.j(; its liy(ir<)- noiinced as their concentration is greater, /.(■., the more there are in a gi\en \-olunie. A base, on the other li.uid, is a compound wlio.se aqueous solution conlains Irec Indroxvl (() II) ions, and when an acid neutralises a base the only change which takes place (provided the solution is dilute and the acid and base are " strong ") is the union of the free hxdroxyl and hydrogen ions to form water. It will beobser\ed that, according to this conception of the m.itter, neither the metal or acid radicle takes any part in the change ; they remain as free ions throughout — H + K + M + O H =M -f- R -f- 11 0 H (where K is the acid radicle and M the metal). It must not be forgotten that the older definitioiis alluded to above are practical ones, whei^eas thi.s ionic definition depends entirely upon hypothesis ; the latter, however, affords a remarkably simple explanation of many well-known facts. When, for example, equivalent weights of strong acids (say, hydrochloric or nitric) neutr.-ilise strong bases (say, caustic potash or soda), the quantitv of heat evolved is always the same. This fact is easilv understood on the above supposition, since in each case the only change in the arrangement is the union of hvdroxyl with hydrogen. If the ;icid or base, or both, are not " strong,'' the heat change on neutralisation w ill be different from that in the previous case. Thif. is explained by saying that the weaker acids and bases arc not entirely in a state of ^8 KNOWLEDGE & SCIENTIFIC NEWS. [April, 19O4. " ionisation " or dissDciation to begin with, and require to be further broken up bsfore the hydrogen and hydroxyl can combine. What exactly is to be understood by the strength of an acid or a base was for a long time the subject of dispute. It used to be said that sulphuric acid was stronger than hydrochloric or nitric acids, because it " turned them out" from their combinations with bases. Sodium nitrate, for example, when distilled with sulphuric acid, gives sodium sulphate and free nitric acid. The test of strength, however, when applied in this manner, is not legitimate, since the nitric acid is not given a fair chance ; it is re- moved from the sphere of action by vaporisation. A much more rational way of arranging the encounter was that devised by Thomsen when he mixed, in dilute solution, one eijuivalent weight of each acid with one equivalent weight of base. Here there is in- sufficient base to satisfy both acids, and all the substances concerned, before and after the action, remain dissolved together without any removal. The two acids then strive for the base, and the one which gets most of it is the " strongest." In this way it is possible to arrange the acids in the order of their "strength," and experiment showed that hydrochloric and nitric acids head the list in such an arrangement. Sulphuric acid proves to be only about half as strong as nitric or hydrochloric acids— a result altogether at variance with the older ideas. The problem has been attacked also from various other points of view : it is known, for example, that the salts of weak acids or weak bases may undergo what is called hydrolysis in aqueous solution, that is to say that Salt + water = acid + base. Such an action can easily be shown in the case of ferric chloride or sodium borate. It was proposed, there- fore, to classify acids as weaker or stronger accordmg to the extent to which their salts were " hydrolysed " by water under similar conditions. Again, there are many chemical changes which are found to be greatly accelerated by the presence of acids, and if these changes happen to be sufficiently slow to enable one to map out the rate of change, it is possible to compare the influence of different acids. Results obtained in such ways agree, on the whole, remarkably well with the order of "strength" as measured by the "stri\ing for base " method. The electric conductivity again was found to be better for the stronger acid ; and the same is true with regard to the deviation from the " normal " osmotic pressure abo\e referred to (Article I.). Such observations were largely instrumental in leading up to the new theory. If one " believes in ions,"'^ it is a comparatively simple matter to explain, in terms of the hypothesis, what is meant by the " strength " of an acid. The strongest acids, like nitric and hydrochloric acids, undergo complete, or nearly complete, ionisation when dissolved in a moderate volume of water, whereas the weaker acids, like acetic or hydro- fluoric acids, are ionised to a less extent. In other words, a moderately diluted solution of hydrochloric acid contains a (relatively) large number of free hydrogen ions in a given volume, and an equivalent quantity of acetic acid contained in the same volume gives rise to (rela- tively) few free hydrogen ions. But ionisation increases as dilution increases, so that we arrive at the conclusion, which sounds paradoxical at first, that when their aqueous solutions are infinitely diluted all acids would be equally " strong " \ The strength of an acid, then, depends, according to these ideas, upon the concentration of the free hydrogen ions which is attained when an equivalent weight of the acid is dissolved in water and the solution made up to a given volume. But how are we going to measure this, or compare it, say, in the case of two given acids ? The complete explanation of the way in which this can be done would perhaps be out of place in a brief sketch like the present one; we will merely attempt here to give a very rough indication of the principle. The electric conductivity of an acid in solution depends upon the number of free ions present in a given volume and upon the speed with which they move. If we determine (directly or indirectly) the molecular con- ductivity of a given acid (i) when the solution is moderately dilute, and again (2) when it is infinitely dilute, it can easily be shown that the first number divided by the second will tell us the extent to which the acid is ionised in the moderately dilute solution. We can then make similar experiments with other acids under the same conditions, and so compare the extent to which each is ionised. Assuming for simplicity that each acid splits up into two ions, one of w hich, of course, is hydrogen, it is evident that the one which is most ionised is the strongest under the given conditions, i.e., there will be more free hydrogen ions in a given volume of solution. The extent of ionisation of the acid can also be arrived at from other considerations, such as the deviation from the normal osmotic pressure (see Article I.); but the electric conductivity method is the most generally applic- able. The Problem of Cancer By Felix Oswald, B.A., B.Sc. • At the present time il is well to look upon this ionic explana- tion as a very efficient and complete working hypothesis, and not to regard it, as is often done, in the light of a creed or dogma. The failure of bacteriologists to discover a cancer- bacillus has facilitated future investigation regarding a probable cure for cancer by narrowing the issue and disposing of a fruitless line of research. On the other hand, the recent important discovery of Professor Farmer and his colleagues, that cancer-cells agree with reproductive cells in only containing half the number of chromosomes in the nucleus after nuclear division, re- calls the experiments of Galeotti,'" in 1693, with regard to the unsymmetrical and irregular nuclear division in cancer-cells. It appears probable that the efficacious preventive treatment of cancer is to be sought in the direction indicated by these experiments, which have hardly received the attention they deserve. Briefly stated, Galeotti treated acti\ely dividing, epithelial cells of salamanders with dilute solutions of drugs such as antipyrin, chloral, quinine, cocaine, nicotine, potassium iodide, &c. The action of these substances caused asymmetrical and tripolar division of the nucleus, exactly similar — as the accompanying figures will show — to the asymmetrical and tripolar division which takes place in cancer-cells in a human subject. The remark- able similarity between these pathological occurrences * Beitr. zur patholog. .\natomie und zur allgem. Pathologie, XIV. 2 ; Jena, 1S93- April, 1904. KNOWLEDGE .^ SCIENTIFIC NEWS. 59 points to the inevitabu .:: .usion that ^ "^i -"^ ^^ "^i Blake's Historica.1 Cha-rts. Mh. ^\"ILLI.\^r Pii.AKK h.is compiled a series of Historical Charts, designed to show in a sort of bird's-eye view the course of Enslish IIistor\- in different year periods. Chart No. I. gives a general vieu of English History from 1066 to igoa. Chart No. H., intended to be used with the other Charts, and a most useful supplement to them, gives contem- porary European rulers from 1066 to igo2. Succeeding Charts cover various pliases of English History from the Roman Dominion in Britain to the reign of Queen Victoria. The Charts have been very carefully compiled at the cost of immense labour, and are designed for the use both of students and teachers. April, 1904..] KNOWLEDGE & SCIENTIFIC NEWS. fir The Ancestry of the CaLrnivoraL. By K. LvnrKKKK. CoMTAKi;!! with the more advanced types of ungulate, or hoofed, mammals, such as the horse, the camel, and the true ruminants, all the Camivora are in many respects much less specialised animals, more especially as regards the structure of their limbs. By this I mean that although all of them are thoroughly adapted to their own special mode of life, while in many instances they are some of the most active, most highly organised, and most intelligent of all animals, yet they depart much less widely from the primitive type of mammals in general than is the case with the more specialised ungulates, or indeed, than ungulates collectively. In none of them for instance, docs the number of toes on each foot ever fall below four, while in some cases the typical five digits are retained in at least one pair of feet. Then again, although in the members of the cat tribe specialisation is displayed by the development of sheaths for tlie protec- tion of the sharp and sickle like claws, the terminal joints of the toes are always of the primitixe claw-like type the unguiculate form, as it is termed by naturalists, and never make any approacli to either nails or hoofs. More- over, all the Carni\ora are characterised by the absence of that tendency to a reduction of the number of the bones in the limbs by the fusion of two together and the disappearance of others, which, as we ha\e seen, form sucli striking features in the evolution of the more specialised t)pes of hoofed animals. .Such consolidations and reductions in the bony framework are indeed striitly correlated with and necessary to the develipment of a small number of hoofs on each foot, and are, therefore, from the very nature of the case, conspicuous by their absence in the Carnivora. Indeed, if we except the frequent disappearance of the collar-bones, or clavicles, the skeleton shows none of that anialf;atnation or loss of some of its elenients, coupled with the e.\cessi\e development of others, which are such noticeable features in the more specialised ungulates. Then, again, the teeth of the Carnivora, though ad- mirably adapted to the special needs of their owners, are much less widely removed in structure from the primitive, or generalised, mammalian than are those of the higher hoofed mammals. The cheek-teeth, for instance, never display that heightening or broadening of the crown, coupled with those deep infoldings of the grinding surface, seen in the molars of the horse and the ox. Moreover, unlike what so frequently takes place in the ungulates, the front teeth are always well developed, and rarely fall below the typical mammalian number of three pairs of incisors and one of canines, or tusks, in each jaw. In- deed, when a reduction in the number of the teeth does take place, as in the cats, whose short jaws do not leave room for the full complement, such reduction takes place at the hind end of the series. Among living Carnivora the group which is in the whole the most generalised and the least widely removed from the primitive ancestral type is that of the dogs — including under this name not only the animals properly so called, but likewise wolves, jackals, foxes, etc. To enter into a consideration of the structure of the skeleton would obviously be an impossibiliiy on this occasion, and it must accordingly suffice to mention that while thetypical number of five toes are retained in the fore-foot of nearly all members of the group, in the hind foot there are only four ; and that although collar-bones arc developed, yet they are reduced to mere rudiments. One other impor- tant circumstance in coniU'Vj^u-^wilii i'kirJi^rt'-^^ iiiusl, however, be noticed. If tno ikjVu"^ (TT Uu; wnsfTor car- pus, of a dog be compared wYl'l^'^Wifr? ^ mau or of ;h:fr'^u;;;:r^r::::«sSK>^^ elements. This is due to tTie fusion of iwi of the bones, the scaphoid and lunar ; dKP tAiki)iHid£)^clI^Jhtliteristic of all modern Carnivora, in which the coni])nund bone is known as the scapho-lunar. One other feature — and this connected with the denti- tion— is very characteristic of modern land Carnivora. In the skull of a cat, dog, or wolf (fig. 1 ) it is well known that one pair of teeth in the side of ea( ii jaw dilier markedly in size and structure from all the rest, the upper biting upon the lower pair with a more or less scissor- like action. It is with this pair of specialised teeth that a tiger or a lion cuts up the masses of flesh torn from its prey into convenient lengths for swallowing ; and these formidable weapons are consequently known as the car- nassial, or flesh, teeth. Curiously enough, these teeth do not serially correspond with one another. It will be seen, for instance, both in fitfure i ;in(l fi«'/. I- O CO ■1S3M Aprii , 1904 ] KNOWLEDGE & SCIENTIFIC NEWS. r.^ The next feature to be noticed is the general slope of the repon. Towards the Mare Iinhriiun on the cast, the face presented by the Apennines is exceedingly bold and steep; towards the Mare Serenitatis an; Geminorum ; his posi- tion with respect to that star may be seen on reference to the chart given in the January number. IMeteor SiiowiiKs : — ■ Radiant. Character- istics. Dale. R.A. Dec. Name. h. m. Apr.ij-May i 16 0 + 47° T IlFrculids Small , short ,, 20-2I 17 20 4- 30'^ TT 1 lerculids Swift; 111. white ,, 20-2J IS ., + ii' Lyrid Shower Swifi .. 30 icj 24 + 59" 0 Oraconids liather slow. The Sr.\RS. — About the middle of the month at 9 p.m. thepositionsof the principal constellations are as follows: Zenith . Ursa Majur. North . I'nlaiis : to the right, Ursa Minor and Draco; to the left, Cassinpeire and I'crseus ; below, Cepheus and Cygnus. South . Leo and Hydra; to the south-east, \'irgo; to the south-west, (leniini (high up), Procynn, and Siriiis (setting). West . Taurus, Pleiades, and Orion, all rather low down. East . Antiinis, Corona, and Hercules; to the north-east, Vi-ga rising. Minima of Algol may be observed on the 7th at 10.38 p.m., loth at 7.27 p.m., and 30th at y.io p.m. Date April 2 „ 4 ,,28 ,,29 Star's Name. 49 Librae . . B.A.C. 339« m Virginis . . B..\.C 4S2S Magni- tude. 5-6 5-9 53 6-0 iJisappcarance. Mean Time. II. 4 p.m. 925 pm- 10.6 p m. 9 40 p.m. Angle from N- point 94 118^ Reappearance. 103- 75' Mean Time. 12.9 a.m. 10.33 p.m. 11.18 p.m. 10.37 p.m. Angle from N. point. Moon's Age. 297 284° 303" 327° d. h. 17 17 9 o 13 o 14 o The Planets. — Mercury should be looked for in the N.W. shortly after Sunset from the 15th to the end of the month. .Vbout this time the planet is in the most favour- able position for observation for the present year, and sets about two hours after the sun. On the 21st he arrives at greatest easterly elongation of 20 1 1', and although this is not so large as the autumnal elongation, the greater inclination of the ecliptic to the horizon at this time puts the planet into a much more favourable position tor observation. The diatneter of the disc is 8"-o. \'enus cannot readily be observed, as she only rises about half an hour in advance of the Sun, and is thus lost in the bright dawn. Mars is practically unobservable, as he sets before it is really dark. Jupiter was in conjunction with the Sun towards the end of last month, and is therefore too close to the Sun for observation. Tei.i;sc()Mc Oi3Jec'is: — Double Stars:—-, N'irginis, Xll.'' 37"% S. o'-' 54', mags. 3, 3 ; separation 5"'7. Hinary system ; both components are yellow, though one is of a deeper hue than the other. 3-m. An eyepiece of a power of 30 or 40 is reijuired to effect separation. rr Bootis, XIV.'' 36™, N. 16^ 53', mags. 4, 6; separa- tion 6". K'equires a power of about 40. I Boc/tis, XIW' 41"', N. 27° 30 , mags. 3, 6i; separa- tion 2"-7. Very pretty double, with good colour contrast, the brighter comiwjnent being yellow, the other blue green. ;. Bootis, XI\'.'' 47™, N. 19' 31 , mags. 5, 7; separa- tion, 2"'4. Binary ; one component being orange, the other purple. Clusters :— M 3 {Canes Vauitici). XUl.'' 38"% N. 28 48'. This object, though really a globular cluster of myriads of small stars, appears more like a nebula in small tele- scopes. It is situated between Cor Carnii and Anturus, but rather nearer the latter. KNOWLEDGE & SCIENTIFIC NEWS. [April, 1904. ASTRONOMICAL. M. Ja.nsserv's Photogra.pKic Atla^s of the Sun. Some twenty-eight years ag(i, M. Jansscn set on foot a photographic study of the solar surface at the Meudon Obser- vatory, of a somewhat special kind. His object was to obtain the greatest possible sharpness of definition, and for this pur- pose he had an objective constructed for him by I'razmowsUi which brought the rays near the G line of the Fraunhofer spectrum, and practically these alone, to a well-defined focus. In conjunction with this instrument he used collodion plates, sensitised by bromo-iodide, in which the iodide predominated, with a small range of sensitiveness which corresponded to the region of the spectrum for which the object glass had been constructed. The photographs were therefore obtained almost by monochromatic light, and were exceedingly' sharp. The objective employed had an aperture of 0-135 metres and focal length of 2 metres, a secondary magnifier enlarging the image of the sun in the telescope some 15 diameters. Some of the most characteristic and best defined from the store of over 5ooo negatives which have now been accumulated at the Meudon Observatory have been reproduced, enlarged four times from the originals, in a superb atlas, recently published by M. Janssen. These plates, 30 in number, and 21 inches by i >i ,, Camelas , , Cavielus. 28, I St . ,. 28 , top ,, Aliicamclas , Alticavielus. .. 25 . 1 .. ,, Procamelas , Procamelus. s , , bottom ,. Paracamelas , Paracamchis. 4-', .. .. 33 , , top ., La da , La do. .. 2nd , ist line .. A'»/0 , Giilo .. ., line 35 . bottom , Maiayensis , Malayenses. .> .. .. 24 , , Parachivomys , Metachiromys ,. ,. 12 , , Soemmeringi SLcmnierringi. BOTANICAL. The rare occurrence ofstamens developing inside the ovary has been recently met with in a Caryophyllaceousplant, Mclandi-yum ruhnim, and is made the subject of a paper by Professor F. Bucbenau in the Bericlitc lier DeutscJitu Butuiiisclieii Gesdhcluift. XXI. The material was collected in the neighbourhood of Marburg, Germany, having tirst attracted attention on account of the absence of petals. A closer examination revealed great irregularity in the structure of the ovary and in the number of the stigmas, and on making a section of the former it was found to contain six to nine, sometimes ten, well-developed stamens arising from its base, the central placenta, with the ovules, being altogether wanting. Dr. M. T. Masters, in his V'fgvtiilih- Teraioloi^y, refers to a Myrtaceous plant, Dicckca itiosmicfoliii. in which a similar abnormality was found. The ovary contained no ovules, but numerous stamens, in various stages of development, were attached to the inside walls. In other respects the flower appeared to be quite normal. The standard work on the flora of South Africa is, of course, the Flora Ciipciisi.-i. which was begun bv Harvey and Sonder, and is being continued under the editorship of Sir \V. T. Thiselton-Dyer. This work, of which anew part hasjust been issued, gives full descriptions, with synonomy and localities, of all the known flowering plants of Africa south of the tropics, and is necessarily bulky and expensive. Professor Henslow's South Afruaii Fluu-crini; Plants, lately published by Longmans, Green, and Co., will be welcomed by those who seek a handy inexpensive work on the South African flora, but who do not require the fulness of the Flora Capi-nsis. The very imperfectly known flora of Siam is being investi- gated by Mr. F. N. Williams, who has commenced an enumera- tion of the plants of this country in the last number of the Bulletin lie VHcrhkr Boissier. His work is based on the material in the Kew Herbarium. Collectors have paid very scanty attention to this flora, and several sets of plants, said to be from Siam, are shown to be from localities outside its boun- daries, and cannot, therefore, be included in his enumeration. Some preliminary remarks on the flora were made by the same author in the Journal of Botany of September, 1903, where he mentiors the interesting fact that the well-known commercial product, Siam benzoin, is obtained not from Siam but from a locality in the Lao province of French Indo-China' PHYSICAL. Chlorophacne. Chlorophane is the name given to those varieties of Fluorite (Fluorspar Calcium Fluoride), which possess to a noticeable extent the property of " thermo-luminositv," that is to say, of spontaneously emitting light when heated. The tempera- ture at which this phenomenon takes place is not the same in all cases, but varies with different varieties of the mineral — the heat required being generally between 300 and 400' C. On first heating little or no light is emitted, until what mav be called the " critical temperature " is reached, when the Chloro- phane glows brightly and continues to glow for some hours after cooling to ordinary temperature, but more feebly. The colour of the light varies, blue and green predominating. Hagenbach found that the spectrum of phosphorescent Fluorite consisted of onl}^ nine bands, four blue, two green, two yellow, and one orange. .As the relative intensity of these bands is continually changing, it is easy to understand the different colours pre,sented by different varieties of this mineral. The pure white Fluorite does not possess the properties of Chloro- phane, apparently the presence of some other salt or impurity is necessary, as in the case of phosphorescent Calcium Sul- phide. * * * ChlorophaLne a.rvd P.adium. Madame Curie states [Chanual .V.ai, \'ol. L.X.X.WUL, No. 2293, p. 223), that: "Fluorite when heated undergoes a change, which is accompanied by the emission of light. If the Fluorite is afterwards subjected to the action of Kadium an inverse charjge occiu's. which is also accom- panied by an emission of light." This being so, what effect would be produced by first acting upon the Fluorite with Kadium, and then applying heat ? The following experiment was devised for the purpose of ascertaining this. A small crystal of Chlorophane was exposed for six hours at a distance of two millimetres from 10 milligrams of Kadium Nitrate (Giesel's preparation) in such a manner that only the (3 and 7 rays acted upon it. The initial fluorescence excited under these conditions was fairly bright, and persisted after removal but slightly diminished in intensity, and when kept at uniform temperature fell to half value in two to three days, dying down to negligible quantity in six to seven days. The changes in thermoluminosity were very marked, a very slight rise in temperature, such as that produced by placing the crystal in the palm of the hand, sufficing to increase the luminosity about 100 percent. This increase is at the expense of the duration of retained fluorescence. The "Alpha" rays of Kadium are without appreciable effect on Fluorite. Careful observations made with a Bismuth plate covered with a deposit of Markwald's Kadio-tellurium (Polonium ?) of sufficient radio-activity to cause a piece of Willemite to glow brightly when in close contact, gave only negative results. It would be of great interest to know the exact nature of the change occurring in the chlorophane, whether it is of a chemical or physical kind. — Ernest L. Arnibrecht, M.P.S. [N.B. — The writer also finds that the above properties are not confined to Chlorophane, but are also shown by Kunzite, with which very pretty experiments may be made on above lines.] Wireless Telegraphy Experiments between Germany and S\veden. The Berlin Gesellschaft fiir Drahtlose Telegraphic some time ago installed two wireless telegraphy stations on the Norwegian Loffoden Islands, the two points chosen being 50 km. distant and separated by high continuous rocky masses, so as to oppose serious obstacles to the passage of the electric wave. These stations were designed for dry cell operation, in order to ascertain whether communication over distances as high as 50 km. would be possible with such small amounts of electric energy. This, however, was found not to be the case as the primary energy of a limited number of dry cells proved insufficient, a cpnsumption of about 200 watts being necessary to overcome the obstacles on the passage of the electric waves. The experiments between Germany and Sweden, as con- templated for some time past, were begun on December i6th, when wireless telegraphy communication was secured between Oberschiinweide, near Berlin, and Karlskrona, a Swedish naval station, over a distance as high as 450 km. The results so far obtained are said to be quite satisfactory. The " Telefunken " system used is a combination of the Braim and Slaby-Arco schemes which, we learn, is being fre- quently used with the Swedish Navy. The Nationa.! Physical La.boratory. One of the prominent even tsof the past month w.is the annual visitation and inspection of the important standardizing and testing laboratory at Bushey House, Teddington. Erstwhile a Koj'al domicile, the mansion and adjacent buildings are now April, 1904.] KNOWLEDGE c^- SCIENTIFIC NEWS. 73 devoted to experimental work di'siL;iu ,, , note the joint interests of the nation's manufacturing industries (in the con- duct of which appUed knowledse is requisite) and theoretical inquiry of a scientific character. Probably few of the .general public who visit Bushey Park in such numbers are aware of the proximity of the National Physical Laboratory, still less of its. aims, .although it is a public institution maintained by means of the taxpayers" money. Here, however, a great work is unob- trusively going forward.whose benefits spread themselves far .and wide. Many .and varied are the investigations pursued. In electricity, for example, is one on the effect of temperature on the insulating properties of materials used "in dynamos, motors, and transformers; in thermometry a researcli on the specific heat of iron at high temperatures ; in metrology, the standardization of the steel yard and nickel metre; and in metallurgy a series of tests on nickel steel. Then, in the de- partment of engineering, experts say that the inquiries in hand are eminently useful to a producing country such as England is, and hopes to remain, despite her foreign competi- tion. Comprised in electrotechnics are tests on electrical instruments, ammeters, wattmeters, voltmeters, and other in- dispensable adjuncts to the needs of industry, .\gain. in chemistry, optics, and photometry, the record of investigation bears the same tendency. The laboratory is, of course, a young organisation as yet ; but its operations are ramifying in all directions under the able giuidance of Mr. K. T. Glazebrook. F.R.S. But, as Lord Rayleigh, the Chairman of the General Board, pointed out the other day, unless adequate funds are provided to meet the national purposes of the foundation the institution must fail in accomplishment, and a starved laboratory would jirobably prove a worse evil than none at all. Besides, it should be borne in mind that Paris and Washington have recently fol- lowed the example of London in initiating standardising establishments intended to help national industries each, too, is subsidised in a far more liberal way than in our own case. The necessity for making better provision for the needs of the laboratory has lately engaged the earnest attention of the Executive Committee, and representations have been made to His Majesty's Treasury- on the subject. A detailed scheme for the future organization and development of the institution has been drawn up and submitted. This, if approved, will entail a revision of the existing Parliamentary grant-in-aid. but in view of the special functions of the laboratorv, and the sphere of usefulness that lies before it, strong hopes are enter- tained of a favourable issue to the appeal. COR.R.ESPONDENCE. A Novel Electric Traction System. To THE Editors ov •' Knowledge." Sirs, — The scheme described under the above heading in your March issue, taken from the Ekctrotechiiisclwr Aii^.cii^cr, presents such curious features that one is inclined to doubt whether it has been put forward seriously. To use electricill v- heated steam-engines in preference to electric motors would appear, at any rate at first sight, as an absurdity, as the following considerations will show. It may be safely assumed that the internal thermal efficiencv of a steam locomotive does not exceed 10 per cent., I'.t'., only 10 per cent, of the thermal energy carried by the steam froin the boilers into the cylinders is converted into work on the piston. So that, accepting 90 per cent, as the efficiency of the electric heaters, and assuming the mechanical efficiency of the engines to be as high as go per cent., it follows that of the elec- trical energy supplied to the V)oiler all that is available for propulsive power is go per cent, of 10 per cent, of 90 per cent., i.e., about S per cent. Against this the ordinary electric loco- motive would have, as stated in the article, an over-all efficiency of 60 to 70 per cetit., or even more. Now although the actual energy for a water-power installa- tion in a sense costs nothing, the plant to develop it is very costly ; and it may be safely predicted that it would not pay to use a generating plant and transmission system eight or nine times too large to save scrapping the steam locomotives. This very large ratio .against the electro-thermal system would, it is true, be reduced by the fact that every locomotive would to some extent act as an eiiualiscr of the demand on the power-houses, reducing the excess plant that would ha\e to be installed ; but the larger system worked from one powerhouse, the less this advant.agc would becoTuc ; .ind in ;iny c.isc the excess of power retjuired by the electro-thermal system would be enormous. Even if under any conceivable conditions such a system might prove advantageous, it is certain that the figures put forward to justify the proposal are mitirely erroneous; and this confirms one's doubts as to the scheme having emanated from any authoritative ([uarter. The first point to be noted is that it is proposed to raise the temperature of the water from 10" to up C. recpiiring iHo calories per kg.; but lyo" C. is said to correspond to a steam pressure of 50 kg. per sq. cm. As a matter of f.ict, iqo° C. (= 374" F.) corresponds to satur.ited steam at about 170 lbs. per square inch (above atmosphere), whilst 50 kg. per sq. cm. is equivalent to 710 lbs. per square inch. However, as pressure is not referred to further by the writer this discre- pancy does not matter much. But next it is said that to raise 4000 litres of water through 180" C. will take 4000 X 180 = 720,000 calories; this is true if it remained water, but this amount of heat is by no means enough to convert the water into steam, i.e., to provide the so-called latent heat of evaporation. So that, whilst it might be correct to say that a consumption of 1000 kg. of hot water per hour at lyo" C. would take zz^ kilow.itts, it is very far from the truth to say the same of 1000 kg. of steam. To convert 1000 kg. of water at 10- C. into steam ;it i()o' C. will take, not 180, but about 635 calories per kg.; in other words. 635,000 calories per hour must be provided ; and if I calorie in the boiler requires i'275 watt-hours, the electrical energy will have to be supplied at the rate of 810 kilowatts, or more than three-and-a-h.alf times the figure given. .\n electric locomotive taking 810 kilowatts might be relied upon to give 700 to qoo effective horse-power; the electric steam locomotive taking the same electrical power, and evapo- rating steam at the rate of 1000 kg, per hour, would not give more than 100 to 125 effective horse-power, if so much. Your obedient servant, .A K SOLD G, Hansard. 53. Victoria Sti'eet. Westminster, S.W'., March cj, 1904. Snake Stones. To THE Editors or " Knowledge." Sirs. — Some time ago I was much interested in a series of articles in the scientific column of a weekly paper on the subject of " Snake Stones." Nothing was said at the time in connection with Brazil, and as I lived in th.it country for several years it may be interesting to some of your readers to have a word on the subject. " Snake stones " are not stones at all. at any rate not in Brazil, and I should think they would be much the same all over the world. • In the articles above referred to there appeared to be gr*-at doubt as to what they are. The only ones used in the part of Brazil where I was were made from the horns of young deer, burnt or carbonised in a peculiar manner, which leaves it very suctorial, and which is kept as a close .secret by a very few men who make them for sale or barter, and try to make out that they have alu)ost supernatural power to heal snake bites. They are usually sold in pairs, and are not by any means common. In form they are about one inch in length, four-sidcKi, and slightly tapering to one end. When anyone is l>itten by a snake, one of these " stones " is placed on the spot and held close, while a band of some sort is tied tightly round the limb a little way back towards the trunk. The " stone " is allowed Jo remain . on the wound until its own weight makes it f.dl ofl, when it is' presumed all the poison has been extracted. It is then dropped into milk and allowed to soak. It is said th.it if the person is to get healed theiailk will turn to ,i dark bniwn. colour, the fact being, I suppyse.'fMat the blood held by tge . stone has that effect. As usual 'with these things, there are many superstitious beliefs in connection with these "stones," ■^.% -^ 74 KNOWLEDGE & SCIENTIFIC NEWS. [April, 1904. and the cure is supposed to be miraculous; whereas I suppose that it is really due to the great capillary attractive force they possess, which extracts a certain amount of blood, and with it the poison. After being thoroughly washed out and dried they are ready for another occasion. Yours truly, James Searle. [Some experiments recently made in the Government Bac- teriological Laboratory of Natal ha\e shown that the mysterious curative properties ascribed to snake stones are quite illusory. — Editor.] The Ancestry of the Elephants. Sir, — In the very interesting article on the above subject by Dr. Smith Woodward in the February number, I notice that he calls the fig. No. 6 on p. 13— (Head of Tetrabelodon angustidcus restored) — a fanciful sketch. As a matter of fact, there has been introduced into it a series of circular wrinkles evidently copied from those on the proboscis of the African elephant figured just above it. But it is clear that, as this proboscis was not pendent, no such wrinkles would appear. Moreover, it would seem more probable that its form would not be circular, but rather shaped to fit the elongated chin. In that case the mouth would act as a long pair of leathery tweezers, very suitable (with the help of the incurved tusks) for gathering in large mouthfuls of long, quick-growing marsh vegetation. The sharp incisors would enable this to be quickly cut off, and the ponderous animal could without delay move his weight on to firmer ground to masticate the food at leisure. As the species moved further north to harder ground and tougher vegetation, a more prehensile grip would be useful rather than a speedy way of gathering food together, whereas the incurved tusk and elongated mandible would not only be useless but highly inconvenient. Thus as the proboscis became longer and rounder, the lengthened chin disappeared entirely ; and the mammoth with its highly developed molars was able to subsist even on the hard and tough vegetation within the Arctic Circle. Herbert Drake. Verwood, Dorset, February 26, 19(^4. REVIEW OF BOOKS. Animal Studies, by David Starr Jordan, Vernon Lyman Kellog, and Harold Heath. (New York and London : Appleton and Co., 1903.) This admirable little treatise is one of the " Twentieth Century Text Books," and bears a very close resemblance to the volume on " Animal Life " — also of this series by the same authors — reviewed in the columns of "Knowledge" in igoi. It differs indeed, mainly, in the addition of several chapters on Classification ; and on the economic value and past history of animals. As an elemen- tary text book of Zoology it must take high rank among works of its kind, and will doubtless find a ready sale in this country. Here and there, however, great opportunities have been missed, and more or less serious mistakes are made. Thus, in the chapter on the Classification of Birds, the auks and pufiins are placed with the grebes and divers, the authors having been apparently led astray, like the older systematists, by the curious structural resemblance which these birds present in common. As a matter of fact, however, the resemblance to the grebes and divers which the auks, puffins, and guille- mots present are entirely adaptive. Their nearest relatives are, without question, the plovers and gulls. So, too, with the gulls and terns, these have nothing whatever to do with the petrels and albatrosses with which they are associated in this book. The resemblances which they severally present are again adaptive. It is equally misleading to place the owls with the accipiters. Turning to the mammals, we may remark that, as with the birds, the classification adopted is antiquated. Nevertheless, in spite of the defects to which we have drawn attention, the work is one which we can heartily commend. Pictures of Bird Life, by R. B. Lodge (Bousfield;, illustrated j 27s. 6d. net. — Mr. R. B. Lodge has produced a most delightful book. The illustrations, which are very numerous, are all re- produced from his own photographs of birds and their nests taken from life. We see many such photographs nowadays, but none better than those reproduced in this book. There are eight full-paged plates reproduced by the three-colour process from photographs coloured by hand. We must con- fess that we would sooner have had these photographs with- out the colouring, which, in most cases, is not altogether true to Nature. The letterpress is interesting, and often very in- forming. Mr. Lodge has made the most of his opportunities, and tells us how and where he obtained his photographs. He has photographed birds in the Dutch marshes, Spanish inaris- mas, and Danish marshes and forests, and in many places in England besides. He gives many valuable hints to those who would take up bird-photography, and describes several in- genious devices and tricks which he has himself used with success. The most notable of these is his automatic electric photo-trap, whereby he traps the bird's portrait by hiding the camera and inducing the bird by bait or otherwise to touch a piece of silk, and thus set an electric battery at work to release the shutter of the camera. Many of Mr. Lodge's observations on the habits of the birds which he has watched so long and so closely while trying to secure their portraits are most valu- able. He may not have discovered much that was unknown, but his remarks are the result of direct and careful observa- tion, and this can never be without great value. There are several repetitions in the book which might have been avoided by more careful editing. The sentence, " The Hooded Crow I do not remember seeing so far south" (Enfield) (p. 124), might be put in a less ambiguous form. The bird is, of course, to be seen commonly further south than London. Mr. Lodge will find that the vibratory noise made by woodpeckers is heard not only in the spring (p. 138). But these are only small points, and are only mentioned in view of a possible second edition of this excellent book. BOOK NOTICES. The Grant and Validity of British Patents for Inventions, by James Roberts. .M..-\., LL.H. (John Murray, one vol. ; price 25s.). This work has been written for and from the point of view of the inventor. It is intended to enable him to confine his claims to what can be supported and to avoid errors in his specification. The first part consists of the principles and rules affecting the grant and validity of British patents, and the practice respecting the atnendaient of specifications both before the Comptroller-General and the Law Officers of the Crown; the second part of abstracts of cases, illustrating the application of these priuciples; and the third part, the statutes and rules. The scope and tenour of the book are such as to make it useful to practising lawyers as well as to inventors. Mathematical Crystallography, by Harold Hilton, M.A. (Oxford : The Clarendon Press). Mr. Hilton's expressed purpose is to collect in this volume those results of the mathematical theory of crystallography which arc not provided in the modern text books on that subject in the English language. He includes a valuable summary of the geometrical theory of crystal structure which the labour of Bravais Jordan. Schneke, Fedorow. Schoenflics. and Barlow have now com- pleted. It is a student's book ; an advanced, but an extremely valuable one. Zoology, Descriptive and Practical. (Two Vols. D. C. Heath; price 4s. 6d. and 2S.) — The general plan of the volumes is to introduce each of the larger groups of animals by a careful study of a typical representative. BOOKS RECEIVED. The Naturalist's Directory (L. Upcott Gill) :— Introduction to the Study of I'hvsical Chemistry, by Sir William Ramsay— a wholly admirable allocution to stude'nts. (Longmans, Green.) Martins Up-to-DateTables of Weights and Measures. (T.Fisher Unwin.) April, 1904] KXOWLl'DGl-: lS: SClENTll'lC Xl-WS. 75 Modern Navigation, by W. H:ill. K.N. (Organised Scionce Sories.i L'niversitv Tutorial I'ross. _ SeconJ Stage Botany, by J. M. Lowson. (Organiseci Science Series. I Iniver^itv Tutorial Press. Entropv.bv lames Svvinbunu-. iConstable.l The .Modei Engineer Series.— X-rays, Simple Experiments n Electricity, The Locomotive, Acetylene Oas. ( IVrcn al Marshall.) A School Geometry. Tarts 1. IV.. by H. S. Hall: IV. and v.. F. H. Stevens. (Macmillan.) We have received from Messrs. Nalder Bros., ot \\ est- minster, their catalogue of Electrical Testing and Scientific Instrument!!. The catalogue is, in itself, an e.\trenuly in- teresting summary of the investigations now binng carried on in various departments of research, and special attention may be directed to the photometric apparatus. Tin following hocks an- in pnpurtttUm at the Claraulon Press i - Suess' •' Das Antlitz der Erde." authorised English transla- tion, by Dr. Hertha Sollas. edited by Professor W. J. Sollas, with preface by Professor Suess for the English translation. Koval i-vo. ,, , "Index Kewensis Plantarum Ph,anerogamarum. Supple- mentum secundum. 4to. Goebels -'Organography of Plants," authorised English translation, by I. Bayley Balfour, M..\., F.K.S. Vol. II. Roval Svo. Mr. Henrv Frou.dc u-ill also publish shortly :— •• \ History of the Daubenv Laboratory," bylK. T. Gunther. Conducted by F. Shillington Scales, f.r.m.s. Royal Microscopical Society. February 17, Dr. Henry Woodward, Vice-President, in the chair. An old microscope by Bate was exhibited, probably made early in the last century. Mr. Stringer contributed a paper on an attachment for reading the lines in a direct-vision spectroscope, and Mr. E. M. Nelson a paper on the vertical illuminator. The author said that, after lying in abeyance for 25 years, the vertical illuminator had lately come into notice for the examination of opaque objects, and especially for the microscopical examination of metals. He criticised the four forms of this apparatus at present sold, namely, those known as the ToUes, Beck, Powell, and Reichert forms, and said that a vertical illuminator must not be an oblique illumina- tor, but must be capable of illuminating the full aperture of the objective with a parallel beam of light. It must not impair the use of the objective for ordinary work, and must, there- fore, not be a permanent attachment. The reflector must be placed near the back lens, and there must be some method for regulating the illumination. Mr. Nelson found that the Powell form, which, like Beck's, consists of a nosepiece con- taining a reflector, more nearly conformed to these conditions, but the reflector should be made much larger and the hole in the side of the nosepiece should be as large as the Society's gauge. To obtain the best advantage with vertical illumination oil-immersion ol>jectives should be used. The distance from the source of light to the mirror and thence to the objective should be equal to the distance from the eyepiece to the objective. At the hole at the .side of the nosepiece there should be a carrier for diaphragms of various sizes in preference to a wheel of diaphragms or an iris. There should also be a strip of metal with a slit in it which could be drawn across the hole in the nosepiece, and the direction of the slit should be in a line with the edge of the flame of the microscope l.uiip. Another paper l)y Mr. Nelson, "On the Influence of the Anti- point on the Microscopic Image Shown Graphically" was also read. The author referred to a papt^r in tlic Journal for 1903 on "A Micrometric Correction for Minute Objects." wherein he stated by way of illustration that, if one of the minute spinous hairs on a blowfly's tongue was exaiuiiied on a bright ground and on a dark ground, a considerable difference in the sizes of the two images was diseeniilile, aiul that the diflerence was caused by anti-points. .\ talile was also given showing the amount to be ailded to the niicronietric ineasureinent of the image seen on the bright ground to bring it up to its true \ alue. Mr. Gordon, who had originated the theory of the anti-point, had made accurate drawings of the two images of the hair, and the ratio of the breadths of the hair in the drawings was as 45 to 05. Applying the corrections given in the table to the measurement of the apparent size of the hair on a bright ground, the actu.il size works out to 12 per cent. more. A ditference in the apparent size of objects when viewed on a bright or dark ground was recognised many years ago, but never explained, but M r. Gordon's admirable anli- point theorem has unlocked the riddle. Mr. Keith Lucas followed with a paper "On a Microscope with (Geometric Slides," the principle enunciated being .applied by the author of the paper to the fine and coarse adjustments' and to the sub-stage of a micro- scope, which was illustrated by lantern slides. The Qviekett Microscopical Club. The aniiu.il gem ral meeting was held on 1 i bruary 19 at 20. Hanover Sipiar.-, the President, George Massee, ICsq., F.G.S., in the chair. .Xfter the usual business had been trans- acted, a ballot was taken resulting in the election of Dr. Edmund J. Spitta, L'.K.A.S., as President for the ensuing year. Mr. Frank P. Smith was elected Editor in succession to Mr. D. J. Scourfield, and Mr. Arthur Earland, Secretary. Dr. G. C. Karop, who has held the secretaryship for over twenty years, goes into well-earned retirement, carrying with him the grati- tude and esteem of all the ineml)ers. The other ofticers werc^ re-clectcd. The President delivered his annual address, dealing with the commoner fungoid diseases of garden trees and plants. These may be divided into two groups, according to whether the mycelium of the fungus is situated in the woody tissues of the plant ("perennial mycelium "), or whether only the season's growth, the leaves and fruit .are affected. The first division, of which the well-known " peach-curl " is an instance, is by far the more serious of the two, it being practically impossible to cure a plant which has become badly infected. In the second division, the plant becomes automatically purified, for a time, on the removal of the infected leaves, &c., either artifi- cially or in the course of nature, and if suitable measures are taken to prevent the germination of the spores in the following season, the plant may be wholly cured. Fire is the best destructive agent; the infected leaves should be burned. Spraying is ineffectual, for the mischief is under the surface, and spraying tends to spread the disease to fresh hosts by washing the spores off the infected plants. The chief causes of fungoid disease in cultivated plants are overcrowding and the use of chemical manures, which kill the nitrifying bacteria of the soil and stimulate the plant to an excessive and weakly growth. After the usual votes of thanks. Dr. Spitta was installed in the Presidential Chair, and in returning thanks for his elec- tion, referred t<^ >^> >^> -^^ Chess Colviran. With reference to our note last month requesting opinions on this subject, we have to state that, having only received nine replies, of which seven were in favour of the retention of the Chess Column, we feel that the subject is not one of sufficiently widespread interest to warrant our devoting the space to it, and, therefore, we must, for the present at all events, discontinue the Notes and Problems. LAST YEAR'S WEATHER— APRIL, 1903. DISTRIBUTION OF MEAN TE.MPERATURE. RAINFALL. 7 3 0? ^ p^ — -^ ' 57 . y ■JOk' 2 2S '2 °' ^4^ The greneral distribution over Scotland differed from the normal, the isotherms ha\ing a north and south direction instead of west and eaj»t. Elsewhere the differences were less marked. T he actual \alues were, witliout exception, below the average the deficienc> as a rule being from 2- to 3;^=. Rainfall was ver>' irregular both as regards the quantit>' and the frequency, there being localities of excess and of defect in each district, iome stations having twice as many days with rain as others in the same neighbourhood. KDomledge & SeleDtifie Hems A MOXTIILV JOURNAL OF SCIENCE. Vol. I. No. 4. [new series.] MA\', 1904. r Entered at "1 LStationers' Hall J SIXl'ENCH Contents and I\'otices. — See Page VII. Racdio-Activity OLnd R^QLdium. By W. A. Shenstone, F.R.S. 1. \\ E owe the discovery of radioactivity, and therefore that of radium, to an accident, though the phenomenon itself might almost be said to be a common one. Radio- activity was first noticed by M. H. Becquerel, who, stimu- lated, perhaps, by Rontgen's brilliant discovery of tie X rays, was looking, in 1S96, for yet other new radiations. The accident was as follows : There is a salt known as potassium and uranium sulphate which, when it is exposed to sunlight, becomes for a moment self-luminous, and Becquerel was studying this phenomenon photographic- ally. His experiment consisted in placing crystals of the salt above photographic plates well protected from light by means of black paper, and then exposing the salt, which was outside the black paper, to the direct light of the sun. When he did this it became evident that some radiation or some emanation was produced which could penetrate the paper, for the photographic film immediately below the salt was so acted upon that when the plate was developed he obtained a silhouette of the crystals more or less like that shown in fig. i, though this par- ticular silhouette was given by a little radium bromide, and not by the uranium salt studied by Becquerel. Fig I. — Silliouetti given iv Radium, One day, just as everything was ready for an experi- ment, clouds covered the sun, and Becquerel put away his plates with the crystals upon them, thinking them spoilt. Several days afterwards liedevcloped the plates and found to his surprise that thesiliioucttes were particularly strong ones. lie found, in short, that the sun was not needed to stimulate the salt; that this latter, without any such stimulant, radiated or emitted something which was able to penetrate black paper and act likr light on a sensitive photographic plate. Me found as the result of further experiments that this was no temporary quality of the salt. It persisted for days and months, and, as he dis- co\-cred subsequently, even for years. I'"urther, the same power was possessed by other uranium salts and by the metal uranium. Anyone who can take photographs can verify all this for himself quite easily. The radiations thus discovered by Becquerel are called ■'Becquerel Rays." They resemble the Riintgen rays in many respects, and at one time were regarded as due to Rimtgen rays. Thus, they cause damp dust free air to deposit fog, make air conduct electricity, will pass througii such substances as paper, glass, paraffin, quartz, sulphur, Iceland spar, and thin layers of metal e\en more freely than Rontgen rays, and they cannot be reflected, re- fracted, nor polarized like the waves of which ordinary light is composed. It was found, further, that they are not homogeneous, but consist of several different radiations which can be filtered off from each other as it were, and can then be distinguished by their separate characteristics. Bodies which emit these remarkable radiations are said to be " radio-active." As we shall see presently, other metals besides uranium are radio-active, and also the waters of some springs, as, for example, the waters at Bath, and even solid earth. Becquerel's great disco\-ery soon proved prolific. It suggested to Madame Sklodowska-Curie the idea that the great radio-activity of specimens of pitchblende, which exceeded that of the uranium present in them, nuist be due to special constituents, and so in her hands and those of others led to the discovery of polonium, radium, and actinium. And the remarkable properties of these new substances in their turn have started new ideas or revived old ones in several departments of science. Madame and Monsieur Curie and their colleague, M. Bemont, discovered polonium and radium, and INI . Debierne was the discoverer of a third substance of the same class, actinium. The method of working was to separate the components of the pitchblende, which is a very complex mineral, and to study the radio-active power of each con- stituent. The results obtained with the bismuth and barium from this mineral arrested attention, and presently it was found that the former was associated with the sub- KNOWLEDGE & SCIENTIFIC NEWS. [May, 1904. stance now called polonium, and the latter with the radium which plays such an important part in modern science. Neither polonium nor actinium have as yet been isolated in the form of a salt. The former in many ways resembles bismuth, and its nature still remains doubtful. Radium, on the other hand, yields salts — e.g., a bromide, a chloride, and a nitrate. Its combining weight has been fixed by Madame Curie at 112-5, and 225 is suggested for its atomic weight. Itexhibitsadefinite flame spectrum, which has been recorded by Messrs. Runge and Precht, and which is given in fig. 2, whilst its spectrum in the ultra violet has been studied by Sir William Crookes and others, and affords a means 'of idcntilying it. Fig. 2, — The Flame Spectrum of Radium. The line ean, another plate will show the point of the stem swaying round in large circles till it comes into contact with its support, and twines round and round the stick provided for it. Professor Pfeffcr, of Leipzig, in 1900, devised a \-ery perfect apparatus of this sort for class demonstra- tion, the photographs being taken by electric light with a film kineniatotjraph. I'.ul the expense of this appa- Sparmannia a.fricana. •MiKiS I IK. 14. t"'S- IS- 1 1 shows the general appearance of the inflorescence, taken at 5 a.m. riowers just opening lr()ni the ritjht po.sition. Kig. 12. Photograph 10 shows bud on the left swelling. f-ijf. i.i. -Photograph Ho. The bud is half open, and the bud on the right is in the vertical position, read> for opening. Hig. 14. Photograph 150. ISoth flowers open. Fig. 15.— Phot ,>graph 220. Still further open. cannot be watched by the eye, and which last over a considerable period of time has, no doubt, often been thought of, but has not been put to much practical test. In fact I know that some years ago, two eminent pro- fessors of science visited one of the popular places of entertainment to watch a boxing match on the screen, with a view to obtaining hints for the use of the kine- matograph for scientific purposes. I did not hear that the experiment went any further. In the plant world there are many fascinating sub- jects possible. If photographs of a germinating seed are taken by the kinematograph at regular intervals during many days until the seed has germinated and sent up its seed leaves, the photographs can be thrown on ratus is too great for the use of amateurs, as, exclusive of the initial expenditure, each new film costs go marks = £^ los. I hope to explain in the following pages the method of working a smaller and less expensive appa- ratus, which is within the reach of the ordinary amateur photographer. The first plant selected for experiment was Sparniannia africana,''- a native of South Africa well known in our greenhouses. A photograph is given of the inflorescence of this plant (fig. ii), which gives some idea of its general appearance. It is a plant which belongs to the same order as the Lime Tree, and has many attractive features ; Annals of Botany, Vr>!. XVII.. No. LXVIII. Sept , 1903. Figy SparmaLnniac a-frica-na.. -10. Shows stages selected from the Kammatograph photographs in the opening of a bud. p.g. I. Watch the bud. Fg. I ig .1. fig. 4. Fig. .■;. Fig. 0. Fig. Fig. X. Fig. 9. Fig. 10. 84 KNOWLEDGE & SCIENTIFIC NEWS. May, 1904. the buds, which hang down round the stem, only open in sunli,t,'ht at a temperature of not less than ahont 60° F. 26° C., the flowers shut up every night at varyin,t,' times according to their age, opening again each morning for several days, and each day the flower alters in appearance. This can be seen in the drawing — the buds are hanging round the stem — one flower is just opening; there are two older flowers and several in an upright position which have closed, and are about to form fruits. Then the stamens are sensitive, and when touched move away from the stigma. The way the flowers are arranged on the stem is also interesting ; the buds hang down at flrst, then move upwards during the night, and then bend again into the vertical position before openmg as in fig. i bud. There is a little joint or pulvinus on each flower stalk where the bend takes place ; when the fruit is ripe a layer of cork is formed at this joint and there the fruit is de- differs in size. It is capable of taking 350 photographs. When ready for use, the disc is put into the machine, which is light proof, and by means of a handle at the side can be rotated, so that every part of the plate is exposed before the small oblong opening in front of the lens and the photographs appear in a spiral on the disc. In ordinary kineniatograph work, the handle is rotated at a uniform speed and a series of snap- shots are produced, but for the work now required, it is necessary to take time exposures, as photographs must be taken at all times of the day and in all weathers ; a large number of photographs are only wanted when rapid movements, such as that made by the stamens when touched or when a bud is opening, are taking place. For miny parts of the day a photograph taken once every quarter of an hour is sufficient. The practical difficulties in this kind of photography Weather Plant lAbms prccatonus ^, 1 \ ^iiiiMiHiim fl -J'. ■■■• ■'^4». "';-. %^iWI9||^ ■ • 1 *^ Fig-. 22. Fig. 23. Fig. 24. Fig. 22. — Photograpli. Position of leaves at 2.18 p.m.. on Marcii 31, 1P04. Fig. 23. — Pliotograpli. Position of leaves at 5.15 a.m., the whofe rachis is moving up, tiioiigti tlie leaves are not yet open. Fig. 24. Photograph. Position of leaves at 10 a.m., April 1, 1904. Fig. 25.— Shows the night position. Fig. 25. tached. This plant seemed, therefore, a very suitable one for experiment. I aimed at photographing the in- florescence at intervals wliile young, so as not only to show the opening of the flowers, their closing at night, and the movements of the stamens, but also the develop- ment of the inflorescence from bud to fruit. I hoped in this way to show the progress of the plant during several months in a few minutes on the screen. My first experiments with a film kinematograph, though successful enough to encourage me to proceed, had many defects ; the machine was not constructed for this sort of work, and the maker was unable to help in adapting it. The celluloid film would not stand the constant damp of the greenhouse, and this was only one of the many difficulties encountered with this machine. My most successful experiments have been with the Kammatograph, in whicii the photographs are taken on a glass disc instead of a film. The disc, 12 inches in dia- meter (half of one is shown in fig. 16) is suspended in a metal ring; it is coated with a sensitive emulsion, just like any ordinary photographic plate, from which it only are rather overwhelming at first, but I have now over- come the principal ones, and think that anyone who cares to try the experiment for himself will find it fairly easy. The expense of each negative plate is 2s. 6d. and the positive is also 2S. 6d., so that the total cost of each completed kinematograph picture is 5s., plus the ex- pense of developing. If this is done professionally, each plate costs is. to develop, thus bringing the cost up to 7s. The developing and printing are extremely simple compared with a film negative, as all the 350 photographs are developed and printed at the same time and in the same way as an ordinary plate ; this seems to me a great practical advantage. Two principal points must be considered : — I. — The apparatus must be quite rigid, as the slightest movement would spoil the whole result. Mr. Kamm has now devised a very satisfactory stand for this purpose. 2. — Each photograph must be exposed uniformly, and, as they have to be taken at all times of day and night, this at first was one of the greatest difficulties. By the use of Wynne's actinometer, this difficu'ty was completely May, 1904.] KNOWLEDGE & SCIENTIFIC NEWS. S5 h < > z ■,'' 1 o D. a a n ■= c: S i! " - . n 1> u 71 4J i O — •= ,^ S u •^ o «.ti w c aj ^ « 7) _ O r, ~ ^c x; o - o " = (/I 0) t/: n ?• o ^^ bti — ■2i ^= = c3 '. B a> * S- * " •I --^ j: f £ a U L- CI) M V M I) 2 N 2 ■= o . c '" £ o j: 0. - a. „• . 00 . " - '. " .^ . "' . LL M M bi il ti. il = 86 KNOWLEDGE & SCIENTIFIC NEWS. [May, 1904. removed. I at first used night exposures ; but this r.ia,:;T.eb!u:ii was very laborious work. I now use an incandescent lamp fed by methylated spirits, but for those who are fortunate enough to have electricity an arc lamp is best of all. When once the right e.xposure is found all further difficulty in this direction is removed. No doubt the ideal method would be to ha\e a clockwork apparatus for turning the machine which at the same time turned on the light and exposed the plate, as Professor Pfefter has. The Sensitive Pla.r\t. — Mimosa seusitiva. This plant closes its leaves when touched, and also naturally shuts them up at night. The leaf is divided into two piniur, each divisi'^n bearing numerous leaf- lets. The best way to make them work is to light a match and put it under the end pair of leaflets at the tip of one of the pinna of the leaf. The first pair of leaflets then shut, then the second, and so on till the Climbing Plant {Mucuna nivca"\. Fig 29. Fig. 20. Fig. 28. Figs. 26 and 27.-Pliotographs. Show the tip of the stem turning round the support. Fig. 2S.-Photograph. Shows the same tip appearing on the other side of the support. Shows the tip applied closely to the support. Fig. 20. — Photograph. whole pinna is closed ; the same stimulus then closes the two leaflets next the stalk of the neighbouring /jwm,, and the leaflets close one after the other till the tip of the leaf is reached. Every leaf on the same branch follows suit, .\fter some time the leaf-stalk falls, another leaf closes m the same way, until the effect of the stimulus is at an end. These photographs are taken as quickly as possible consistent with giving the right exposure, and require a whole plate. A second plate shows the leaves reopening, taken at intervals of about five minutes: the exposures were con- tinued until the leaves shut into the sleep position for the night. The more common species, .1/. pudica, serve equally well lor experiment. The Weather ¥^\3.r\i.—Ahnts precahriiis. There has been much discussion about this plant lately as to whether it really predicts the weather to be expected in the future. I have a series of photographs extending over one complete day, whici. ......v. the regular day and night movements of the plant. The plant was kept in a glass case sheltered from wind and sun at a temperature not below 73° F. = 22-5° C. The plant was placed with the rachis (midrib) of its youngest leaf facing north. The photograph was begun at 11.30 a.m. on Thursday, March 31, 1904, and continued until 10.30 p.m. It takes up the sleep position at 4.30 p.m. Then the photograph was begun again at 5 a.m. on .\pril i, while the leaves v.-ere still shut. As the sun rises the leaflets gradually open, and each leaf raises itself so quickly that one can watch the movements easily. The kinematograph seems to afford a means of defi- nitely settling this question. The photographs give an unbiassed record of the movements of the plant and the weather reports, barometrical and thermometrical read- ings, records of earthquakes, &c., can be provided by the various meteorological stations, so that if a re-investiga- tion is ever considered necessary after Professor Oliver's* exhaustive report on the subject the data could in this way be obtained. Climbing Plants. — This is a very fas- cinating subject for the Kammatograph. ( )ne has to focus the support on which the plant is climbing and to keep the tip of the climbing stem in the held. .\s the plant grows in length the Kam- matograph has to be raised. In showing the photograph with the lantern a jerk will be noticed every time this is done, so if it can be arranged to alter the stand every morning one can see how much the plant has twined each day. Anyone who takes the trouble to photo- graph a climbing plant will be surprised at the very curious movements of the tip. The way in which it circumnutates, turn- ing to every point of the compass, then gives a twist when it comes into contact with its support, is very fascinating. The real difficulty with the climbing plant is that it grows and climbs just as much at night as it does in the day, so that if it is not photographed at night there is an interruption when projecting it with the lantern corresponding to the beginning of each new day. I am afraid a perfect photograph of a climbing stem will not be attained without clockwork apparatus, as the trouble involved of sitting up all night for at least a week would be too much to expect, even of the most ardent photographer. The plant illustrated is a Calcutta stem-climber, Muciina invca. It was photographed for a week from 6.30 a.m. to 11.30 p.m. I hope in these few pages that I may have succeeded in interesting some of the readers of " Knowledge " in the work of making animated pictures of plants, and shall be only too glad if I can be of any use to anyone who wishes to try these experiments. The illustrations of such a subject are naturally disappointing, as they cannot appear animated, but if anyone will take the trouble to cut out the ten figures of the opening bud of Sparmannia africana (Figs, i-io) and paste each on a card or luggage label, and fasten them together closely at the 'ower end, by letting each figure pass before the eye they appear animated and will give some rough idea of will what the plate will show when projected with a lantern. • Kew Bulletin, Jan , 1890. M.' AY, 190; KNOWLEDGE & SCIENTIFIC NEWS. The ** Canals" of Mars. A Reply to Mr. Story. Hv K. Walter Mainiiek, I'.K.A.S. Several correspondents having expressed a strong wish that I should give some reply to Mr. Story's letter on this subject, I will endeavour to do so ; not without reluctance, as the line which Mr. Story took seemed, in my opinion, hardly likely to advance our knowledge. If I may briefly summarise Mr. Story's objections to the paper communicated by Mr. Evans and myself to the Royal Astronomical Society last June, they come under three heads. He objects to me as the author, to the methods employed, and to the deductions drawn. The first objection is of course a somewhat delicate one for me to handle. It deals rather with the personal than with the scientific, and I have no inclination to fill the columns of Knowledge with detailed evidence of my claim to be considered an " expert " on the subject of Mars. Let it suffice that as long ago as 1877, I had made a thorough study of the planet, using the fine 12^-inch Merz refractor of Greenwich Observatory. In 1892 and 1S94 I also used the 2S-inch Grubb refractor — certainly one of the most perfect objectives in existence. I give two or three examples of my earlier drawings, from Fig. I. -Drawings of .Mars made witli the I2,=incii Refractor of tile Royal Observatory, (ireenwicii. H, M. I. 1877 September 29th 10 10 3. 1879 November 5th.. 13 5 It. M. J877 September 241I1 11 43 lf5Sj January yth 12 2 which it will be seen that I had recorded some of the markings now familiar to us as " canals " and " oases," even before Schiaparelli had published his results, and quite a number before they had been generally recognised by observers. So much for the person, next for the methods. Mr. Lowell and Mr. Story both appear to object to the employment of terrestrial experiments to elucidate plane- tary appearances. Mr. Lowell's opinion to tiiis effect may be found in his letter published in the " Observa- tory " for January, 11)04, p. .[g : '• Permit mc, in con- clusion, to point out to you . . . that the only evidence germane to the matter is to be got from astronomical observations directed to that end." But as Mr. Story points out, Mr. Lowell himself has set on foot terrestrial experiments for the express purpose of drawing infer- ences with respect to his observations of Mars, and Mr. Story approves of his so doing. Kliminating what is common to the two cases, the one of which meets with Mr. Story's approval, and the other with his disapproval, the only residuals are Mr. Lowell on the one hand and myself on the other, and the statement is reduced to the simple proposition that he approves of Mr. Lowell and disapproves of me, irrespective of our actions. In other words, his second objection is but a more diffuse way of restating his first. But to take the matter seriously, let us see prt;cisely what is the point where Mr. Lowell's \'iews and my own diverge. It is not in the chief markings of Mars. Mr. Lowell sees and draws these substantially as I saw and drewtheni in 1X77, and as Beer and Miidler drew them in 1830. It IS not in respect to the appearance of the " canals " ; 1 observed and drew " canals " as far back as 1S77, and though of course Mr. Lowell has seen and drawn far nion; " canals " than I have, those that I saw were substantially of the same character as his ; and in the discussion of this cpiestion 1 have been most careful, both in writing and speaking, always to point out that 1 was not throwing doubt eithtrr on the fidelity or the skill of any of the observers of Mars. Mr. Evans and myself wrote : •' It would not be in the least correct to say that the numerous observers who have drawn 'canals' on Mars during the last twenty-five years, have drawn what they did not see. On the contrary, they have drawn, and drawn truthfully, that which they saw." (" Monthly Notices" \'ol. LXIIL, p. 499.) Nor have I ever asserted or assumed " that the canals are seen as very faint lines, so faint that their existence is doubtful even to experienced observers." 1 know the reverse by actual experience. We agree on a third point. Mr. Lowell is absolutely convinced, and in this 1 am quite at one with him, that it is not possible that an actual network so geometrical as that which he represents can be the result nf purely physical causes. Mr. Story has no doubt seen the very fascinating book which Mr. Lowell published on "Mars" in November, 1895, and has read the pages 148-154. After this we differ. Mr. Lov/ell attributes this con- fessedly utterly unnatural network to the handiwork of intelligent beings who have woven over their planet these "grotesijue polygons" to use Schiaparelli's expression. This, be it nijted, is inference, not observation ; and an inference which demands the assumption that, were i\Iars brought much nearer to us, or our power of seeing greatly improved, these grotesque polygons would still persist, and would never resolve themselves under better seeing into markings which we could reasonably ascribed to the unaided processes of Nature. My inference is different; the unnaturalness may be due to the imperfection of our seeing. I rely on well- known facts respecting the theory of vision and the structure of the eye, and the eye is our necessary instru- ment for observation. We have no right to resort to the unknown and the artificial, before we have exhausted 88 KNOWLEDGE & SCIENTIFIC NEWS. [May, 1904. the known and natural methods of explaining a pheno- menon. My inference is one based on the observed effects of known causes; Mr. Lowell's inference is an ex- cursion into fairyland. We know that the smallest single dark marking on a bright ground which can be seen by an observer of per- fect sight, without optical assistance, must have a diameter of at least 34 seconds of arc. This diameter depends upon the size of the rods and cones of the eye which receive the visual impression, and compose the sensitive screen. It is therefore an inevitable limit. .\s this diameter is necessary for the object to be merely perceived, or, in other words, to create any sensation at at all, it follows that in order that the actual shape of the object may be recognised, its diameter must consider- ably exceed this limit, otherwise it will be seen as a truly circular dot, whatever its actual shape. This is the case for small isolated markings just within tlie limit of visibility. The case is different for extremely elongated markings ; the increased length of a marking will compensate for diminished breadth up to a certain limit, but not beyond it. For a Ime of indefi- nite length the limit of breadth approaches two seconds of arc. A line of a breadth below one second of arc is invisible, no matter what its length ; but it must have a breadth many times this amount before it can be seen as anything else than a mere line — before irregularities in shape and breadth can make themselves apparent. In naked-eye vision, therefore, there is a considerable range within which small objects, whatever their true shape or nature, can only be seen as dots or as lines. The result is that these two forms are certain to come in evidence whenever we are dealing with objects too minute to be fully and properly defined. The problem becomes more complicated when we are using optical assistance, as there is a limit of definition belonging to the telescope as well as to the eye. But the principle remains the same ; the result of adding the limitation of the telescope to the limitation of the eye being that the actual magnification of the telescope can never be nearly as effective as it is nominally. A power of 300 on the best telescope in existence, and under the best atmospheric conditions, would never show the features ot the moon as distinctly as they would be seen if the moon were brought 300 times as near. Mr. Story and Mr. Lowell both object that terrestrial (or, as they are more usually called, " laboratory ") expe- riments are altogether beside the mark when applied to the interpretation of astronomical observations. The contention is a ridiculous one, and if logically applied would render it impossible to determine the instrumental errors of a transit circle by the use of meridian marks, collimators, or mercury trough, or the personal equation of an observer, except by actual stellar observation. They would also foibid us to identify the lines of solar or stellar spectra by comparison with those of any terres- trial element. Hut since it is contended that Mars alone can give us valid information on the subject, to Mars let us refer. If we turn to the drawings made by Beer and Miidler in 1830, two small objects exceedingly like one another appear repeatedly. These are two dark circular spots, the one isolated, the other at the end of a gently curved line. Both recall the "oases" which figure so largely in many of Mr. Lowell's drawings, and the curved line at the termination of which one of the spots appears, is not unlike the representation which has been given of several of the " canals." There can be no doubt that in the year 1830 no better drawings of Mars had appeared than those to which 1 have referred, and that in representing these two spots as truly circular Beer and Madler portrayed the planet as they best saw it. The one marking we call to-day the Lacus Solis, the other the Siinis Siihifus, and we can trace the gradual growth of our knowledge of both markings from 1830 up to the present time. The accompanying sketches of the same region 7^ r 2. ^- '/^ ^ * Fig. 2. — Sinus 5aba;us and Lacus Solis. Sinus Sab.-eus Lacus Solis Beer and Miidler i»30. Lockyer . . 1862. SchiapareMi . . 1890. Beer and Miidler 1S31. Lockyer .. 1S62. SchiaparcUi .. i8go. by Lockyer, in 1862, and by Schiaparelli, in 1890, illus- trate well how the character of the markings revealed themselves with increased telescopic power and experi- ence in the observer. •' At first it seemed a little speck And then it seemed a mist, It mo\ ed and moved and tooli at last A certain shape I wist. A speclv, a mist, a shape." If Beer and Madler, in 1830, had argued that the precise circularity of these two spots, as they appeared to them, was proof that they were artificial in origin, would they have been correct? Would not the answer have been valid that a spot too" small to be defined must appear circular, and that, therefore, the apparent circularity pro- bably covered detail of an altogether different form ? We know that it would. Yet it is that same argument in a far stronger form against which Mr. Lowell and Mr. Story are contending to-day. Beer and Madler only drew two of these spots ; Lowell shows over sixty. Beer and Madler's two spots seemed to them precisely alike; how utterly different those two spots appear to us to-day the diagram may serve imperfectly to indicate. Mr. Lowell's sixty or more " oases," with one or two exceptions, appear all of the same character. Will any- one dream that if the next seventy years brings telescopic development equal to that shown in the last seventy, the present uniformity of Lowell's "oases" will persist, any more than the likeness of the two spots observed by Beer and Madler? We need not even wait for the seventy years. Up to the present moment I have carefully avoided anything like criticism of the drawings of any observer of Mars. I have repeatedly stated that I ac- cepted them as being both faithful and skillul representa- tions of what the observers saw. Ijut it is necessary here to point out that the extreme simplicity of type of May, 1904.] KNOWLEDGE c