Wmmmfm'''Mmm^^^^^^^^ '-■- ^ THC PROPEHTY Of SniTLV WOKDRD-EXACTI.V DRSCKIHRD. maga E IITERATURE Founded by RICHARD A. PROCTOR. "Let Knowledge grow from Diore to more. " -TENNYSON. VOLUME XXIV. JANUARY TO DECEMBER, 1901, ']Lon^ou : KNOWLEDGE OFFICE, 326, HIGH HOLBORN, W.C. [yin Rights Reserved. \ LONDON : PRINTED :^T KNOWLFDfiE OFFICE, 32^, HKiH HOI.BORN, W.P. / '■^^- U» 'Z.i^- KNOWLEDGE ui. INDEX Algar. H. Letter on Mrs. Quickly's " Table of Green Fields" 88 Animal Products, Some Peculiar— By K. Lydekker 252 Antarctic Exploration — By Wm. Shackleton ... ... .. 121 Antoniadi, E. M., F.R.A.S.— Nova Persei ... ... ... ... ... 250 Arctic Animals turn White, How — By R. Lydekker ... ... • 172 Bacon, Rev. John M., F.R.A.S.— Exploring the Thunder Cloud 4'.i On the Capricious Hearing of Certain Sounds at Long Range ... ... .. 193 Beilby, Ernest L. — Letter on Constellation Studies ... 109 Bell, Arthur H. Rainfall in South Africa ... .. .. 54 The Mechanism of a Sunset ... . . ... 235 The Alchemy of Hoar- Frost ... 258 Bird-loye in Winter — By Charles A. Witchell ... ... ... 8 Books, Reviews of— Amphibia and BcptUcs (The Cambridge Xatui-al History). By Hans Gadow, M.A., F.K.8. ... 255 Asklepios; The Temples and Ritual of, at Epidauros and Athens. By Richard Catoii, m.d. ... HO Astral Gravitation in Xatural Plienomcna, Essays in Illustration of the action of. By William Leigh ton Jordan ... . .. ... 41 Astronomisclier Jahresbericht. Edited by Walter i\ W'islicenus ... ... ... ... 23.3 Astronomy, Primer of. By .Sir Robert Ball .. Ill Astronomy, A Text-book of. By Prof. G. C. Comstock ... ... ... ... ... 278 Atmospheric Radiation. By Prof. Frank W. A'ery 15 Bird Watching. By Edmund Selou, ... ... 280 Birds of Siberia, The. By Henry Seebohm ... 184 Book Circular, Williams & Norgatc's .., Botany, Au ElenuMitary Text for School L. H.Bailey Botany, Handbook of Practical burger Botany, Irish Topographical. Praeger Botany, The Self-Educator in. MA. By Dr. E. Stras- By Robert Lloyd By R, S. Wisharf, Calcidus, The Eleuu>nts of the Differential and Integral. By J. W. A. Young and C. E. Litio- barger Child, The, a Study in the Evolution of Man. By A. F. Chamberlain, M.A., PH.D. Crocodilian.'*, Lizards, and Snakes of North Aiucrica, The. By Prof. E. D. Cope ... Crustacea, Ihe Stalk-eyed, of British Guiana. West Indies aud Bermuda. By Charles G. Voung, 31. A., il.D., M.R.I. A. ... Danvinism, The Elements of. By A. J. Ogilvy ... Deschanel's Natural Philosoph\ — Part III. Elec- tricity. By Prof. J. D. Everett Design in Nature's Story. By Dr. W. Kidd Dragons of the Air; An Account of Extinct Flying Reptiles. By H. G. Seeley ... ... " .. Englishwoman's Year Book aud Directory, 19U1, The. Edited by Emily Janes Evolution, Problems of. By F. W. Headley Faraday, Michael ; His Life aud Work. By Prof. S. P. Thompson, F.ii.3. Harlequin Fly, The Structure and Life History of the. By Prof. L. C. Miall, F.B s., aud A. E. Hammond Heat, What, is ? and What is Electricity ? By Frederick Hovendcu ... . . ... Heavens, The Romance of the. IJy Prof. A. W. Biekerton .. Imitation ; or the Mimetic Force in Nature and Human Nature. By Richard Steel Invention in the Nineteenth Century, The Progress of. By Edward W. Byron ... Inventions, Twentietli Century : A Forecast. l!v George Sutherland, M.A. Keats, The Com])lete Works of John. Edited by H. Buxton Forman ... Kite Observations, Report of the, of 1898. By the Department of Agriculture, U.S.A. Knowledge Diary and Scieutific Handbook lor 1U02 Land and Sky. By the Rev. John M. Bacoti Legislation, Journal of the Society of Comjiarative Lick Observatory, Publications of the ... Lilford, Lord (Thomas Littleton, Fourtli Baron). A Jlemoir by His Sister Magnetism and Electricity, The Principles of. By P. L. Gray, B.sc. Man Mathematics, Elementary Practical. B\ M. T. Ormsbv PAQE 17 87 111 150 IM s7 20(; 234 184 185 64 279 42 41 110 110 134 IGO 111 110 ■M6 lU 1(J 280 (il 111 42 41 l:il 4l' LSI KNOWLEDGE Bv W. H. Books, Reviews of— Mechanical aud Physical Subjects, Papers on. Prof. Osborne Reynolds, F. U.S. Mediterranean Race, The. By Prof. G. Sergi Microscope and its ReTelations, The. Edited by Key. W. H. Dallinger, F.B.s. ... Microscope, One Thousand Objects for the. Br Dr. M. C. Cooke ... Nature, A Year with. ^,v \V. Percival Westell ... Nineteenth Century Science, The Story of. Bv H.S.Williams ... ... .'.. .". Norwegian North Polar Expedition, 1893-G. Scientific Results. Vol. III. Edited by Fridtjof Nansen Observatory, Lowell, Annals of the Observatory, Paris, Annual Report of the Observatory, The Royal, Greenwich. By E. Maunder ... Photograms of the Year 1900 ... Physics, Practical, Advanced Exercises Prof. Arthur Schuster, th.d., f.h.s., and C. Lees, D.sc Plant Studies. By John M. Coulter, ph.d. Plants, Disease in. By H. Marshall Ward, sc.D., IK.S. Plants, Fossil, Studies in. By Dukiniield Henry Scott Plants, Poisonous, in Field and Garden. By Rev. Prof. G. Henslow ... Railway Runs in Three Continents. By J. T. Burton Alexander ... Science, A Manual of Elementary. By R. A. Gregoi'y and A. T. Simmons Selborne, The Natural History and Antiquities of. By Gilbert White. Edited by L. C. Miall and W. Warde Fowler ... Sex, The Evolution of. By Prof. Patrick Geddes and J. Arthur Thomson Shells, Our Country's, and How to Know Them : A Guide to the British Mollusca By W. J. Gordon Smithsonian Institution, Annual Rejjort of the, for the Year ending June 30th, 189s Species, Origin of. By Charles Darwin ... Spermatophytes, Morphology of. By J. M. Coulter, rn.u., and C. J. Chamberlain, PH.D. ... Star Atlas, witli Explanatory Text. By Dr. Hermann J. Klein. Edited by Edmund McClure, M. A. Starches, The Microscopy of the More Commonly Occurring. By Prof. Hugh Gait, M.B., CM., d.p.h. Studies; Scientific and Social. By Alfred Russel Wallace ... Suu, The Path of the. By William Sandemau Universe, The Riddle of the. By Ernst Haeckel , . . Use-Inheritance; Illustrated bv the Direction of Hair on the Bodies of Animals. By Walter Kidd, p.z.s. What is Life I' By F. Hovenden White, Gilbci't, of Selborne, The Life and Letters of. By Eashleigh Holt-White Who's Who, 19U1 Words in Reasoning, The L'se of. By Alfred Sidgwick ... Zoology, Agricultural. By Dr. J. Ritzema Bos ... Zoology. An Elementary Text-book. By A. E. Shipley and E. W. MacBride Zoology, A Text-book of. treated from a Biological Standpoint. By Dr. O. Schmeil Zoology, A Tieatise on; Part IV. Platyhelmia, Mesozoa, and Nemertini. By W. B. Benham ... 203 207 206 110 64 65 183 17 17 IG 16 159 233 206 16 233 111 159 25G 280 280 205 42 183 232 160 42 17 15 278 65 255 42 206 111 279 87 280 Brown, Robert, Junr., F.S.A.— Constellation-Figures as Greek Coin-Types. Carcinology, Current— By Eev. T. E. R. StebbixNg .. Carpenter, Geo H., B Sc.(Lond.)— The Insects of the Sea — Bristle-TaQs Spring-Tails Beetles Flies Four-winged Flies and Bugs Chess Column — PAOB 35 209 ... 19 ... 51 114, 161 ... 194 ... 245 By C. D. LococK ... 24,47,71,95,119,143, 168, 191, 215, 240, 263, 287 Christopher, H. — Letter on The Nebular Hypothesis 89 Climate, Gradual Change in our— Letter on ; by Alex. B. MaoDowall... ... 39 Cobbold, Paul A — Letter on Eainbow Phenomena . . ... 40 Cole, GrenvUle A. J., M.R.I. A., F.G.S — Bound Fair Head 198 Comet, The Great Southern (1901—1.)— By W. F. Denning 201 Comets and Meteors, Notes on — By W. F. Denning 23,46, 70,94,118, 142, 166, 190, 214, 238, 262, 286 Constellation-Figures as Greek Coin-Types- By Robert Brown, Ju.vr. Constellation Studies — By E. Walter Maunder — I. The North Circumpolar Stars n. The Region of Leo in. The Eegiun of \'irgo ... IV. Bootes and Hercules ... V. The Scorpion and the Serpent-Holder 105 VI. The Swan and the Eagle VII. The South Circumpolar Stars VIII. The Archer and the Water-bearer IX. The Sea-Monster and the Flood X. The Royal Family . . XI. The Earn and the Bull 35 12 33 57 85 128 152 178 228 248 273 KNOWLEDGE Constellation Studies — Letter on ; by Ernest L. Bbii.hy Cooke. John H., F.L.S.. F.G.S., etc.— Prehistoric Man in the Central Mediterranean 91 Cornish, Vaughan, D.Sc.(Yiot.). F.C.S.F R.G.S. - The Size of Ocean Waves 1, 55, !»7, 115 Cortie, Rev. A L . S.J.. F R AS. The Types of Sun- Spot Disturbances New Stars ... ... 101 130 Coulton, John James- Letter on Mrs. Quiokly'a " Table of Green Fields" 89 Cowell, P. H.— Prof. Adams' Lectures on the Lunar Theory 15i Cox. A. H. Machell. M A.— The Stronghold of the Nuthatch 101 Crommelin, A. C. D. — Total Solar Eclipses of the Twentieth Century 59 Cross, M. I. — Microscopy 22,45,09,98,117,141, 165, 189, 218, 237, 260, 285 Davison. Charles, Sc.D., F.G S.— The Progress of Seismology during the Nine- teenth Century ... .. .. 44 On the Audibility of the Minute-Guns fired at Spithead on February 1st .. ... 124 The Sinking of Large Stones through the Action of Worms ... ... ... .. 241 Dead Sea, The Water of the— By C. AiNswoRTH Mitchell ... ... ... 259 Denning, W. F., F.R.A.S.— Notes on Comets and Meteors 23, 46, 70, 94, 118, 142, 166, 190, 214, 238, 262, 286 The (.reat Southern Comet (1901, L) 201 The Real Paths of Fireballs and Shooting Stars 271 Earthquake, The Inverness- Note on... Eclipse, The Total Solar, of May 18, 1901 109 By E. W.\LTKR M.\i NnEU ... 225 Eclipses. Total Solar, of the Twentieth Century- - By A. C. 1). CuoMMEr.iN .. ... ... 5!) Editorial 265 Electrograph, A Curious — Letter on ; by Willi.\m Godden ... 89 Elvlns, A. — Letter on Sunspots and J jight . . . 232 Fair Head, Round- By Grenvili.e A. J. Cole ... ... 198 Fingerprints as Evidences of Personal Identity— By R. Lydekkek . .. ... 66 Finger Prints, Human- Letter on ; by W. H. S. Monck ... 90 Fireballs and Shooting Stars, The Real Paths of By W. F. Denninc .. 271 Fotheringham, Rev. D R , M.A.— Mrs. Quickly's " Table of Green Fields " ... 31 FoMfler, A., F.R.A.S.— The Face of the Sky 23, 46, 71, 95, 119, 142, 167, 191, 215, 239, 262, 287 The New Star in Perseus 73 Godden, William — Letter on A Curious Electrograph 89 Gore, J E , F.R.A.S.— The Brightness of Starlight 177 Gowers, Sir W. R , M D., F.R.S.— Letter on Sudden Blanching of Human Hair 231 Green, J. F., F.Z.S.— Letter on Mothing in Suffolk... ... ,. 281 Gregory, R. A. 257 I Letter on Clouds on Mars ... ... ... 133 VI. K NOWLEDGE Hair, Plant-bearing— By E. Lydekker Hair, Sudden Blanching of Human - Letter on ; by Sir W. R. Gowers Hand-Prints, Monlcey— By R. Lydekker Hoar-Frost, Tlie Alchemy of — By Arthur H. Bell ... Human Life Possible on other Planets, Is ?— Letter on ; by Arnold D. Taylor Letter on ; by Thomas R. Warin(5 .. Letter on ; by Arthur En. Mitchell Letter on ; by E. Lloyd Jones Hydrogen, The Second Series of Lines in the Spectrum of— By Edward C. Pickering Ice Age, The— Letter on ; by W. H. S. Monok Icebergs, Amongst Antarctic — Letter on; by H. E. B Insects of the Sea, The — By Geo. H. Carpenter. Bristle-Tails Spring-Tails Beetles Flies Four-winged Flies and Bugs 223 231 Lewis, R. T.— Letter on Double Rainbow 201 258 15 40 41 90 181 158 251 Locock, C. D., B.A.— Chess Column . . 24, 47, 71, 95, 119, 143, 1G8, 191, 215, 240, 268, 287 19 51 114, 161 . . 194 ... 245 Jones, E. Lloyd Letter on Is Human Life possible on other Planets? 90 Letter on Clouds on Mars ... ... 133 Knight, Geo. McKenzie— Letter on The Nebular Hypothesis ... ... 109 Letter on Sunspots and Terrestrial Tempera- ture 133 Letter on A Triple Rainbow ... ... ... 231 Leonids, Photographic Search for— Note on; by E. W. M. 15 Lunar Atmosphere and Oceans — Letter on ; by J. O'M.AY 182 Lunar Theory, Prof. Adams Lectures on the— By P. H. CowELL 154 Lydekker, R. — Monkey Hand-Prints ... ... 3 Living Millstones .. .. ... 28 Finger-Prints as Evidences of Personal Identity .. ... ... 66 Four-Horned Sheep . ... ... ... 150 How Arctic Animals turn White . . 172 Plant-Bearing Hair 228 Some Peculiar Animal Products ... ... 252 A Remarkable Mammal . . 269 McDonald, R. L. Letter on Sunset Phenomenon ... 63 MacDowall, Alex. B., M.A.— Letter on Gradual Change in our Climate ... 39 Letter on Sunspots and Winters ... ... 156 Letter on Does the Moon affect Rainfall ? ... 276 Mammal, A Remarkable — By E. Lydekker .. ... ... .. 269 Markwick, Col. E. E.— Letter on Sunset Phenomenon 88 Mars, Clouds on — Letter on ; by E. Lloyd Jones ... ... 138 Letter on; by R. A. Gregory ... ... 133 Letter on ; by T. K. Waring ... ... ... 157 Uars, The Canals of — By Miss M. A. Orr 38 Maunder, E. Walter, F.R.A.S.— Constellation Studies — I. The North Circumpolar Stars ... 12 XL The Region of Leo 33 KNOWLEDGE Vll. Maunder. E Walter. F.R AS — Constellation Studies — III. The Region of Virgo ... ... ... 57 I\'. Bootes and Hercules ... ... .. 85 V. The Scorpion and the Serpent-Holder 105 VI. The Swan and the Eagle 128 VII. The South Circnmpolar Stars ... 152 VIII. The Archer and the Water-Bearer 178 IX. The Sea-Monster and the Flood 228 X. The Royal Family 248 XI. The Ram and the Bull 273 Sunrise on the Sea of Plenty . .. 61 Where Four Mountain Ranges Meet... ... 84 The Ringed Plains of the Mare Nubium ... 200 The Total Solar F.clipse of May 18th, 1901 225 Men and Microbes — By E. Steniioise ... ... . 187 Meteor. Brilliant, in California- Latter on ; by S. D. Proctor ... 270 Microscopy — Conducted by M. I. Cross 22, 45, 69, 93, 117, 141, 165, 189, 213, 237, 260, 285 Millstones, Living— By R. Ltdekkek Hinute-Guns fired at Spithead on February Ist, On the Audibility of the— By Ch-vbles Daviso.n ... Mitchell, Arthur Ed.— Letter on Is Human Life Possible on other Planets? Letter on The Distribution of the Stars in Space Mitchell, C. Ainsworth, B.A., F.I.C.— The Water of the Dead Sea Monck, W. H. S.— Letter on Human Finger-prints Letter on The Ice Age Moon, The Orbit of the— By Sir Samuel W ILK s (Moon), The Ringed Plains of the Mare Nubium — By E. Walter Macndeb 28 124 41 281 259 90 157 156 200 (Moon). Where four Mountain Ranges meet- By E. Walter Maunder ... .. ... 84 Mothing in Suffolk — Letter on ; by J. 1'. Green 231 Nebulae, Photographs of the, 1^1 Y. 32 Orionis, Ijj IV. 2 Monocerotis, IJ lY. 28 Corvi. and y I. 139 (M. 61) Yirginis- By Dr. Is.\AC Rohehts . ... 180 (Nebulae), Photographs of the Clusters M. 35 and 1:1 VI. 17 Geminorum, and of Nebulae in Monoceros — By Or. Isaac Roberts ... Nebular Hypothesis, The - Letter on ; by II. Christopher Letter on ; by Geo. McKenzie Knighi Letter on ; by Willia.m Nohle Nile. The White— From Khartoum to Kawa - An Ornithologist's Experiences in the Soudan. By Harry F. WrrnKRiiY — I. The Desert Railway, Khartoum, and Omdurman II. The River— Essential alike to .Man, Beast and Bird III. The Country and the People IV. Camping and Collecting ... V. Birds VI. A Dance, a Sand- Storm, and a Rare Bird Noble, William- Letter on The Nebular Hypothesis ... Noon, Determination of — Letter on ; by Wm. Davies 11 H9 109 109 75 137 174 220 248 266 109 ir.7 Nordenskjbld, Prof. Baron von- Obituarial Notice of .. 230 Notes- Astronomical Botanical ... Entomological Zoological General ... 9, 32, 63, 82, 112. 132, 158, 185, 208. 234, 2r,G. 277 9, 32, 82, 112, 132, 158, 185, 208, 2,34, 257, 277 10, 32, 63, 83, 132, 168, 186, 234, 257, 277 10, 33, (14, 83, 113, 132, ir,H, IHG, 209, 285, 207, 278 11, H3, 113, 186, 257 VUl. KNOWLEDGE. Nuthatch, The Stronghold of the— By A. H. Machell Cox ... ... ... 101 O'May, J.— Lunar Atmosphere and Oceans ... ... 182 Ormerod, Eleanor A.— Obituarial Notice of ... .. 207 Ornithological Notes, British- Bustard, Attempt to re-introduce the Gi-oat, in Norfolk— T. Southwell ... ... ... 183 Bustard, Little, in Derbyshire — W. Storrs Fox ... 205 Butcher Bird, Mimicry by tlie— Charlefi A. Witchell 140 Buzzard, Honey, in Solway — Bobert Service ... 117 Buzzard, the Honey, Supposed breeding of, in Somerset— W. P. Westell ... ... ... 205 Cuckoo, A Young, on iligration — Richard M. Barrington... ... ... ... ... 65 Dotterel, Early Appearance of, in Yorkshire — Philip W. Lotcn ... ... ... ... . 90 Dotterels in Wales— O. T. Aplin . ... 205 Falcon, Hed-footed, in Shropshire— H. E. Forrest ... 183 Fulmar breeding at Cape Wrath — Howard Saunders 43 Godwit, Black-tailod, in Co. Wexford— G. E. H. Barrett Hamilton ... ... ... ... 117 Goose, Lesser White-fronted, in Norfolk— F. Coburn 234 Grebe, Great-crested, An Observational Diary of tlie Habits of the — Edmund Selous ... ... 161 Gull, Ivory, in Northamptonshire— O. V. Aplin ... 205 Ibis, Glossy, in County Durham — T. H. Nelson ... 161 King-Eider in Co. Down— Robert Patterson ... 65 Kite, the Black, Occurrence of, at Aberdeen — George Sini ... ... ... ... ... 205 Martin, House, Winter Occurrence of, in Yorkshire — T.H.Nelson ... ... . ... 91 Migration, Bird, in Great Britain and Ireland — H. F. W. ... 18 Migration of Birds in N.E. Lincolnshire— G. H. Caton Haigh ... ... ... .. 183 Moorhens, Hairy-plumaged— H. E. Forrest ... 117 Names of British Birds, The Origin and Meaning of — A. H. Meiklejohn ... ... ... 4.3 Nightjar, Early A))pearance of the, in Hampshire- Harry F. Witherby ... ... ... ... 140 Nutcracker in Sussex — H. Marmaduke Langdale ... 117 Nutcracker in Yorkshire— W. Ruskiu ButterBeld ... 281 Ornithological Notes from Norfolk for 1900— J. H. Gurney ... ... ... hq Ornithologists, Early— Rev. H. A. Macpheraon ... 281 Owl, Scops, in Shetland— W. Eagle Clarke ... 117 Owl, Snowy, in Co. Donegal— Robert Patterson ... 65 Owl, Tawny, in Ireland— Robert Patterson ... 43, 90, 281 Owls, Long-Eared, as Anglers — Max Peacock ... 65 Pastor, Rose-coloured, ni Kent— L. A. Curtis Edwards 183 Phalarope, Grey, in Lincolnshire— J. Conway Walter 65 " Photo-trapping " Birds — R.B.Lodge .. ... 233 Pipit, Bed-throated, in Ireland — F. Coburn ... 204 Redpoll, Coues, in Barra — W. Eagle Clarke ... 205 Redstart, Nesting of the, in Shetland in 1901 — Charles A. Sturrock ... ... . . _ 254 Riviera, Bird-Migratiou in the— J. It. Gui'ney 205 Sandpiper, Baird's, in Sussex ... ... ... jg Sandpiper, Broad-billed, in Kent ami in Sussex L. A. Curtis Edwards and W. Ruskiu Buttirfield 281 PAGE Sandpijier, Pectoral, at Aldeburgh — E. C. Arnold ... 19 Sandpiper, Pectoral, in Ireland— Howard Saunders 43 Sandpiper, Wood, in Co. Dublin — W. J. Williams... 234 Scotland, Report on the Movements and Occurrence of Birds in, during 1900— T. G. Laidlaw ... 205 Shearwater, Great, Notes on the — Howard Saunders 43 Shearwater, The Little Du>ky (Puffinus axsimilisj, in Sussex — Ruskiu Butterfield ... ... 90 Shetland, Southern, On Some Migratory and other Birds observed in, in September, 190t) — W. Eagle Clarke ... ... . ... 43 Shrike's '• Larder," The— H. F. W. ... ... 43 Starling or Nuthatch— Harry F. Witherby 160 Starlings, Nest of Young, in Winter-R. H. F. ... 43 Surrey, The Birds of— J. A. Bucknill ... .. 205 Swallows, Arrival of — E. Sillence ... 140 Swallows, Migrating — L. M. Sabine Pasley 281 Swift, Breeding Habits of the— Rev. F. C. R. Jourdain and Rev. Allan Ellison ... ...234,281 Tern, Lesser, Nesting at Barra — W. L. MacGillivray 254 Thrush, Song, Notes on the Singing of a — Charles A. Witchell Thrush, Song, On the Winter Singing of the — W. Wai'de Fowler Thrush, Song, The Migrations of the— H. F. W. ... Thrush, Song, The Migration of the— E. Sillence ... Tit, Willow (Paruti xalicariuxj, British Form of the -H.F. W. Tits, Blue, nesting in a Pump — W. C. Tetley Wagtail, Blue-heailed, Breeding of. in Sussex — W. Buskin Butterfield ... Wagtail, White, at Bartragh, Co. Mayo— Robert Warren Wagtail, White, Notes on the, in the South-east of Scotland — William Evans Warbler, Barred, in Barra — W. L. MacGillivray ... Wigcon, Breeding of, in Ireland — Robert Patterson . , . Wigeon, Breeding of, in Ireland — John Cottney . . , Wren, Willow, Nesting of the, in Shetland in 1901 — Charles A. Sturrock... Wryneck calling in August and September— Basil T. Rowsell Yellow Haiuiiier, Red-faced Variety of the — H. F. W. . Yorkshire, Thi' Birds of 116 183 18 65 18 204 281 183 43 117 183 205 254 254 182 19 Orr, Miss M. A. — The Canals of Mars ... Ostracoda, Giant: Old and New — By Rev. Thomas R. R. Stbbbing Peek, Sir Cuthbert E . Bart., M.A., F.S.A. Obituarial Notice of ... Persei, Nova — By E. M. ANTONiADr ... Letter on ; by A. Stanley Williams Persei, Nova, The Stars near— By A. Stanley Williams Perseus, The New Star in — By A. Fowler ... 38 100 208 ... 250 ... 204 .. 152 .. 107 KNOWLEDGE IX. Photography 'in Natural Colours" by the McDonough-Joly Process— I3y H. Snowi'KN Ward Pickering, Edward C— The Second Series of Lines in the Spectrum of Hydrogen ... Plants, Flowering — With Illustrations from British Wild-flowers. By R. Lloyd Praeger — I. Roots and Stems . . II. Concerning Leaves in. Flowers IV. Flowers and Fruit V. Dispersal and Distribution VI. The ^'egetation of Ireland Polar Exploration — Note on Quickly's, Mrs., " Table of Green Fields "- By Rev. D. R. ForHKBixauAM Letter on ; by H. Algar Letter on; by John- .James Coulion Rainbow, A Triple — Letter on ; by G. McKenzie Knight Rainbow, Double- Letter on ; by R. T. Lewis ... isl 25 79 125 160 217 281 lK(j Praeger, R. Lloyd, B.A.— Flowering Plants. \\'ith Illustrations from British Wild-flowers — I. Roots and Stems .. ... ... 25 II. Concerning Leaves . 79 IIL Flowers 12.3 IV. Flowers and Fruits .. ... ... 169 V. Dispersal and Distribution ... ... 217 VI. The Vegetation of Ireland ... 2H1 Pre-historic Man in the Central Mediter- ranean— By . John H. Cooke ... ... 91 Proctor, S. D.— Letter on Brilliant Meteor in California . . 27i> Rainbow Phenomena- Letter on ; by 1'aui. a. CoHiiOLi) Rainfall? Does the Moon affect — Letter on ; by Alex. B. ^IacI)o\vai,i. Rainfall in South Africa — By Arthur H. Bell ... Roberts, Isaac, D.Sc, F.R.S.— Photographs of the Clusters M. S") and y VI. 17 Geminorum, and of Nebuhe in Monoeeros Photographs of the Nebul;r |^ V. 32 Orionis, Jjl IV. 2 Jlonocerotis, y IV. 28 Corvi, and Jjl I. 139 (M. (Jl) Virginis Sandeman, Wm. Letter on The Path of the Sun Sea of Plenty, Sunrise on the— By E. Walter Maunder Seismology, The Progress of, during the Nine- teenth Century — By Charles Davison ... Shackleton, Wm., F.R.A.S.— Antarctic Exploration Sheep, Four-horned- By R. Lydekker 10 27tl 51 11 180 02 01 11 121 150 Silver, Standard : Its History, Properties, and Uses— By Ernest A. Smith 102, l;U, 108 Sky, The Face of the- By A. Fowler . . . Quensel, Percy T. F. K.— Letter on Sunspots and Terrestrial Temperature ... .. 108 23, iO, 71, 95, 119, 112, 107, 191, 215, 239, 202, 287 31 88 89 231 204 Smith, Ernest A., Assoc.R.S.M., F.C.S.— Standard Silver : Its History, Properties and Fses 102,131,10:! Sounds, On the Capricious Hearing of Certain, at Long Range- By Rev. John M. Bacon 193 Speeds, The Relative, of Some Common Birds— By Charles A. Witchell 119 Starlight, The Brightness of— ByJ. E. Gore 177 X. KNOWLEDGE. Stars, New— By the Kev. A. L. Cortie Stars, The Distribution of the, in Space- Letter on; by Arthur Ed. Mitchell Stebbing, Rev, Thomas R. R., M.A., F.R.S., F.L.S.— Giant Ostracoda : Old and New Current Carcinology ... Stellar Parallax — Letter on ; by W. W. Strickland Stenhouse, E., A.R.CS., B.Sc- Men and Microbes Strickland, W. W,— Letter on Stellar Parallax Sun, Constituents of the — Note on; by E. W. M Sun, The Path of the— Letter on ; by Wii. Sandeman Sunset Phenomenon- Letter on ; by R. L. McDonald Letter on ; by E. E. Markwtck Sunset, The Mechanism of a — By Arthur H. Bell ... Sun-Spot Disturbances, The Types of— By tbe Rev. A. L. Cortie Sunspots and Light- Letter on ; by A. Elvins Sunspots and Terrestrial Temperature- Letter on ; by Percy T. F. K. Quensel Letter on ; by G. McKenzie Knight Sunspots and Winters — Letter on ; by Ale.\. B. MacDowsll ., 130 231 100 209 133 187 133 15 62 63 88 235 104 232 108 133 15G Taylor, Rby. Arnold D.— Letter on Is Human Life Possible on other Planets'? 13 Thunder Cloud, Exploring the — By tbe Rev. John M. B.ACON 49 Ward, H. Snowden, F.R.P.S.— Photography "in Natural Colours" by the McDonough-Joly Process ... ... ... C> Waring, Thomas R — Letter on Is Human Life Possible on other Planets'? 40 Letter on Clouds on Mars ... ... 157 Waves, The Size of Ocean- By Vaughan Cornish .. 1, 55, 97, 145 Wilks, Sir Samuel, Bart., M.D., LL.D., F.R.S. Letter on The Orbit of tbe Moon Williams, A. Stanley — The Stars near Nova Persei ... Letter on Nova Persei 156 152 204 Witchell, Charles A.— Bird-love in Winter ... ... 8 The Relative Speeds of Some Common Birds 149 Witherby, Harry F., F.Z.S., M.B.O.U.— The ^Vhite Nile — From Khartoum to Kawa— I. Tbe Desert Railway, Khartoum, and Omdurman ... ... ... ... 75 IL The River — Essential alike to Man, Beast, and Bird 137 m. Tbe Country and the People 174 IV. Camping and Collecting ... ... 220 V. Birds 243 VI. A Dance, a Sandstorm, and a Rare Bird 266 Worms, The Sinking of Large Stones through the Action of— By Charles D.\vison ... 241 KNOWLEDGE XI. INDEX OF THE PRINCIPAL ILLUSTRATIONS. Antarctic Ship '' Discovery " at Dundee 122 Aye-Aye, The (fiiU-pagc Photo2rai>hic riato) .' ... 27l> Comet, The Great Southern (1901, I.) 202 Ditto, Orbit of, aiul of tlie Eui'tli 20H Constellation-Figures as Greek Coin- Types ifull-pa^'o I'liotoiiraphio Plato) ." ... 30 Corona of 1901, May 18 (full-page I'lintojjr.ipluo riite) 220 Crustacea— Leptodora kindtit {Foci.c) ... 211 Ptiichogaster formosus (A. Milne- Edwards) 212 Eclipse, The Total Solar, of May 18, 1901— Mr. Claiton'8 Sfcition and Mr. Maunder'* Station ... ... 2'it\ Our Military Helpers 227 Photograph of the Partial Phase .. 227 Eclipses, Total Solar Diagram showing the tracks of all tliat cross Eui'ope during the Twentieth Century Electrograph, A Curious Finger-Prints Cii <>7 PAOB Early embryo of .\nurida... ... 5-1- Actocharis Seadingii and Cajtii.t fucieota ... ... ... ... 1 ! 5 Fhtitosiis niririeentris and Phyfosus haUicua ... ... ... ... IIG (irwh o{ Difffoiia mcr.':a ... ... Ifil MU-raltimma hre.cipenne, gr\ib and pupa ... ... .. ... 161 Cillenus lateralis ... ... .. 102 Grub of Aepus mariniis and Aepus Sobinii ... ... ... ... 163 Coelopapilipena.nAOriigma luctuosa 19.5 Glenanthe ripicola and Cherso- dromia arenaria .. ... ... )!•."> Aphroit/lus raptor, Male and grub 196 Clunio marinus. male, female, and larya ... 197 jRretmopteraBrownii and ILallri/fus aniphibius ... ... ... 198 Aepophilus Bonnairei (nude), and ITermatobates lladdonii (male) 246 Trochoptis pfiimleiis (female), and JTaloliati'S reffali.9 {vAale) ... 2-t7 Mars. Oppositions of 17 Microscopes, Diagrams of IGo, 160 Fireballs — Diagram showing tlie paths of ... 280 Four-horned Ram Hand-Prints, Monkey — Right Palmar Imprintof a Macaque Monkey ... Right Palmar Impressions of a Capuchin Monkey and of a Mar- moset Right Palmar Impressions of a Spider Monkey and of a Red- frontcd Lemur ... Insects of the Sea, The ilucUilis marilima. Leach. A lirisfle-tad Isoloma marilima, I. nehblli, and /. BesfUii Xeni/lla. humicola and Ancrida maritima ... 1.51 Millstones, Living Denial jilates of an Eagle-ray and a PalR'Ozoic Shark • . . . Crushingteeth of an Enamel-sealed Fish tapper teeth of Beaked Ray Ujiper dentition of the Port Jackson Shark Tootli of the Ridge-toothed Ray .. (Moon), Sunrise on the Sea of Plenty (fidl-pagc- Pliotograiihic Plate) ,. (Moon), The Ringed Plains of the Mare Nubium (full- page Photo- Ui-anliic Plate) 28 28 29 30 30 02 201 (Moon), Where Four Mountain Ranges meet (fnll-pagePhotograplucPlate) 81 Nebulae in Monoceros (full-page Photo- gi-apliie Plate l.y Dr. Isaac Roberts) 1 1 (Nebulae\ Clusters M. 35 and y VI. 17 Geminorum 'full-page Photo- graphie Plate bv Dr. Isaac Roberts) 11 Nebulae — W V.32 0rioni3,¥ I V^2 Monocerot.is, 111 17. 28 Coryi, M. 01 Virginis (Pliotographic Plate by Dr. Isaac Roberts) 180 Nile, The White. From Khartoum to Kawa — .\ Sakieh ... ... ... ... 76 The Riyer Bank, Omdnrman . 77 The " Bazaar" at Khiirtoiini ... 77 The Ruins of the Malidi's Tondi... 78 Mahomet al. Work 137 Sketch-Map showing route ... 138 Boatbuilding on the White >'ile ... 139 A Midday Hall. 139 Building a S A Movable Hut 176 Camps at Duem and Gerasi ... 222 Bleeding Mahomei; ... 21i Tlve Cup fixed on the Neck ... 21.5 The Wreck of a Tent 207 Observatory, Royal Alfred, at Mauri- tius 225 Persei, Nova, and Procyon, Photo- graphs of the Spectraof (full - page I'hotngrapliii- Plate 130 Persei, Nova, and Surrounding Stars (full-page Photographic Plate) ... 152 Persei, Nova, Images of Ordinary Star and the 251 Persei, Nova, Photographic Images of (full-page Photographic Plato) 250 Perseus, The New Star in. Charts of Plants, Flowering Winter leaf-rosette of the Sea- Stork's-bill Winter leaf-rosette of the Hem- lock Slork's-bill Wind- fertilized iilants (Tiipha liilifulia and (1 li/ccria aiiua/ifii) Insect-fertilized plants (Cuii- voliuilii.i iind Angeliva) ... Wdd Angelica and ().^-eye Daisies Tlie Bloody Crane's-bill ... Gregarious Plants— Winter Helio- tiope, Ranisons and Ivy Sketch-Maps Showing Distribution of Plants in Ireland Wild Arbutus at tlic I'ppcr Lake, Killarney Sky, The Midnight, for London - .lanuary 5. 1901 February 5, I9UI March 7, 1901 Ajml, 1901 ■ r3, 75 80 81 126 127 170 217 219 281 2S-1 It 35 59 87 xu. KNOWLEDGE, PAGE P.»OK Sky, The Midnight, for London— No. 3.— The Region of Virgo 58 May 6, 1901 June 2, 1901 . 107 . 130 No. 4. — The Region of Bootes and Hercules , , . 86 July 1,1901 August 5, 1901 October 4, 1901 ... . 154 . 180 . 230 No. 5.— The Region of Scorpio ... No. 6. — The Region of Cygnus ... 106 129 November (i, 1901 . December 3, 1001 ... . 250 . 275 No. 7.— The South Circumpolar Stars 153 Star Maps— No. 8.— The Region of the Archer and the Water-bearer ... 179 Xo. 1. — Xortli CircumpolarEegion 13 No. 2.— The Region of Leo ... 34 No. 9.— The Region of the Sea- Monster and the Flood 229 No. 10.— The Region of the Roval family '... 249 No. 11. — The Region of the Ram andtheBuU 274 Stone, Instrument for Measuring the Movement of a 242 Sunspot Group, Life-History of a (fidl-page Plato) 104 Waves, Diagrams of 146, 147, 148 Jantary 1, 1901.] KNOWLEDGE Founded by RICHARD A. PROCTOR LONDON: JANUARY 1, 1901. CONTENTS. * PAGE The Size of Ocean Waves. By VArnnAx CoBNisn, M.SC.(VICT.), F.C.S., F.lt.O.S. ... ... ... ... ... 1 Monkey HandPrints. Bv K.Lvdekkek. (II lust rated) ... ri Photography ■ in Natural Colours.' by the McDonough Joly Process. Bv H. Snowden- Waup, f.im'.s. G Bird-Love in Winter. By Cuables A. AVitchkll 8 Notes 9 Photographs of the Clusters M. 35 and V VI. 17 Geminorum, and of Nebulae in Monoceros. By Isaac RoBKETs, D.sc, F.K.8. ... ... .. ... ... 11 '■hotographs of the Clusters M. 35 and 9 Vl. 17 Geminorum, and of Nebulae in Monoceros. (Flate.) Constellation Studies. — I. The North Circumpolar Stars. By E. Waltee Maundeb, F.it A.s. (Illustrated) 12 Letters : l3 HiMAN Life Possible on othek Planets ? By Arnold D. Tatloe ... ... ... ... ... 1.5 PuoTOGRAFHic Search FOR THE Leonids. — E. W. M. .. l.'i CONSTITITENTS OF THE SUN. — E. W. M. . . ... ... 15 Notices of Books . 15 Books Rkcf.ived ... ... ... ... .. ... 17 British Ornithological Notes. Coiulnoticl by IIadey F. WiTHEKBV, F.Z S., M.H.O.r. ... ... .. ... .. 18 The Insects of the Sea.— Introductory. Bristle tails. By Geo. H. Cabpeniee, b.sc.(lond.) (Illnstrated) ... K» Microscopy. Gondiict«d by M. I. Cross 22 Notes on Comets and Meteors. By W.F. Denning, f.b. a. s. 23 The Face of the Sky for January. By A. Fowler, f.b A.s. 2.i Chess Column. By C. D. Locock, b.a 24 THE SIZE OF OCEAN WAVES. Bj VAUGHA>f Cornish. m.sc.(vict.j, f.c'..s., p.e.g.s., Aseociafe of the Owens College. " The heights of wares and their velocity are subjects on which obseirations are never amiss." — T''ide Admiral f// Manual of Scientific Enguiri/. Of all the phenomena of our physical environment what is so fascinating j^et elusive as a wave ! Since the earliest days the voyager returned has told about the waves he met, and their bigness, yet even now we cannot get an answer which shall be at once short, clear, and accurate to the question — what is the size of the waves in. a storm at sea? I propose in these articles to describe in some detail what has been done towards answering this question, which, as I know from my per- sonal experience, excites a wide interest. I seek, not to satisfy, but to stimulate this interest, and to. enlist more observers, particularly among those whose oppor- tunities permit of continuous and systematic observa^ tions. Most to be desired are observations from on board ship, in deep water far from land, but observations from the sea shore would also bo welcome, and tlioso from lightships and lighthouses exposed to tho waves would be distinctly valuable. Obsci-vations of the large waves which disturb the sur- face without affecting the bottom of the deep sea can only be made from on boai'd ship, and arc exti-cmcly difficult to can-y out. Nob only aro the phenomena more complicated than in shallow water, wliero some regularity of direction and of speed is imposed by the limitations of depth, but the conditions on a ship aro themselves unfavourable for this class of observations. The principal things to be obsei-vcd are tho diffcrcnoo of level between ci-cst and trough, or the height of the waves, the distance from crest to crest, or the wave length, and the rate at which the crests or ridges travel, the velocity of the wave, and the interval of time be- tween the amval of tho ridges, i.e., tho period of the wave. The height of the waves would be less difTiciiU, to determine if the ship herself did not rise and fall, or if sho floated as a cork, but in practice she does neither the one nor the other, and the difference between the rise and fall of the centre of gravity of the ship and the rise and fall of the water cannot be calculated tlico- retically. Moreover, the obsei-ver cannot watch tho waves from the centre of gravity of the ship, but has to station himself where the level of his eye is also con- tinually being altered by the rolling, and sometimes by pitching. The eye under these conditions Icses its power of judging horizontality owing to the sudden tilts wliich change the apparent direction of gravity. The length between succeeding ridges is less difficult to observe, for the known dimensions of the ship give a rca,dy means of measurement; or a buoy can be towed astern at the end of a line of known length. Frequently the length from i-idge to ridge vai'ies greatly (sometimes in the proportion of 1 to 2, or even 3) for succeeding ridges. We have ill such cases to do with more than one set of waves, for tho length should vary very slightly for suc- ceeding waves of a single set; the observed distances from ridge to ridge are, therefore, frequently, not wave lengths at all in the physical sense, but casual intervals, tho dimensions of which do not enable us to calculate the velocity of tho ridges by means of the theory of waves. Tho velocities of the ridges must, therefore, be directly measured, which can be done by timing the passage of a wave from bow to stern or from stein to bow, making the necessary allowance for tho speed of the ship and the angle between her course and that of the waves. An accurate determination even of the time of passing the length of the vessel is not easy for a single obsei-ver, and the want of concordance between the ship's course and that of the wave often makes accurate measuromonts of velocity impossible. The best plan no doubt would bo to stop the ship, but as traffic becomes more and more concentrated in big, fast vessels, the difficulty of making the n.ecessar7 arrange- ments is coiTcspondingly increased. In tho case of the liners by which most of us now travel, the waves made by tho ship herself interfere with *he obsei-vation of air but large waves. The finest attempt yet made to carry out systematic observations of waves at sea was that of the late Lieu- tenant Paris, of the French Navy ; a pretty full account of who,se work follows, condensed from the original paper in the Rnnie Mnritime ef Cnlnniale, Vol. XXXI., 1871. a publication little known to the ma.jority of scientific men m England, and not vei7 easy of access. Next, for comparison, I give a shorter account of the KNOWLEDGE. [Januaey 1, 1901. observations made on the French ship Astrolabe, from the original paper in the Comptes Rendus of the Paris Academy of Science; and, thirdlv, a summaiy of an important paper in the Phi/osophica! Magazine, for April. 1888, in which the Hon. Ralph Abercromby described his attempts to impart a; higher degree of accuracy to wave measurement. After these summaries of important papers I shall resume a more general treatment of the subject. Lieutenant Paris' observations of waves were conducted on board the Dupleix and Minerie during the years 1867-70 in the Atlantic, Jndian. and Pacific oceans, and in the Japan and China seas. Observations were made in the open sea on 205 davs. Of these 29 were days on which the sea was practically smooth. On the remaining 176 days the heights of the waves were measured, but the detenninations of wave length and velocity were only made in 109 days, there being 67 days during which the divergence between the ship's course and that of the waves prevented accurate observation of length and speed. When the divergence exceeded 45 degrees observation was useless. About 4000 waves in all were measured. The speed wa.s obtained by recording, with a watch having a seconds' hand, the time the wave crast took to traverse the length of the ship, and applying the necessai-y correction for the speed of the vessel. The interval of time between the arrival of succeeding wave crests was also taken, and this, combined with the detenninatioa of speed, gives the wave length or distance from crest to crest. We have then determined by actual observation the speed, periodic time, and length of the waves without having recourse to the theoretical calculation of one or two of these values from the observed value of the other. This is rather important, because without a more elaborate investigation than is usually given we cannot be cei-tain that we are dealing with a single series if waves, and the ordinary formula of reduction from period to length, from speed to length, and from period to speed, is based on this assumption. The values which Lieutenant Paris endeavoured to obtain were not so much the dimensions of single waves as the average dimensions of a number of waves passing the ship during a selected time of observation on each day. The occasion chosen for observation appeal's to have been not a fixed time of the day, but one selected for the state of the sea, the object being to secure as far as possible that the waves should have grown to their maximum dimensions under the breeze. The recorded speed or length of waves for any one day is the mean of at least 10, sometimes as many as 50 waves, and each of these means is treated as a single measurement, "^lien for instance we find recorded that the maximum wave length observed in the Southei-n Indian Ocean was 235 metres (771 feet), this implies that 771 feet was the greatest average wave length observed on any one day, not that it was the greatest distance which separated any two succeeding wave crests. The height of the waves from trough to crest was estimated as follows: — The observer established himself where he could get the crest of the waves passing near the ship on a level with the horizon when he was himself above the trough of a wave. In a comparativelv smooth sea the position of the observer was at one of the lower port holes, in a rough sea he would mount the shrouds. Then, says Paris, the height or amplitude of the wave is easilv determined, for it is equal to that of the eye above the flotation line when the ship is on an even keel. This latter height being known, need not, he says, be determined afresh at each observation. This assumes that the draught of the ship in the trough of the waves is constant, and equal to the draught, in smooth water, which, however, is not the case. Lieut. Paris may either have overlooked the fact or may have decided to neglect the coiTection. There are various means of checking these measurements of waves which were applied when circumstances permitted, and when practice had been attained Lieut. Paris reckoned his measurements to be good to about 10 per cent., one- tenth part of the whole. The strength of the wind was also recorded at the time when the waves were observed. Strictly speak- ing, one should know also how long this wind has been blowing, but that is hardly practicable with a ship on its course except pei-haps in the Trades. The strength of the wind may be measured either by the pressure which it exerts or by its velocity. Paris chose the fonner method, and constructed an apparatus which measured the effective pressure of the wind upon a thin rectangular plate. In order to connect the pressures registered bv the instrument with the velocity of the wind, ol«ervations were taken at favourable opportunities of the time required for light bodies tossed off from the cross-trees to fly the length of the ship. The values thus obtained for tlie connection between pressure and velocity are recorded in the subjoined table. The numbei-s in the fii"st column of Table I. ai-e those by TiBLE I, Wind velocity and pressure according to Lieut. Paris. Xnmbers recorded in the Log. V^il..il r>e«cri[.tion. Calme Velocity in Feet 1 per Second. 0 00 1 Presque calmc 2-63 o Faibl." brise 3 87 3 Legere brise 4-76 4 Petite brise 1394 5 Jolie brise 3412 6 Bonne brise 67-92 7 Vent frais ]28-6 8 Tent grand frais 201-1 9 Coup de vent S.543 10 Tempete 6070 11 Ouragan 820 2 which the strength of the wind is usually recorded when the record depends solely on the estimate formed by the observer without use of instruments. These numbers are roughly proportioned to the square root of the velocity. It was in the southern Indian Ocean between the Cape of Good Hope and the Isles of St. Paul and Amsterdam, in the region of almost continual westerly winds, that the largest waves were observed. On the 25th October, 1867. during a gale from the N.W., with violent snow squalls, thii-ty waves were measured at different times of the day which averaged 29.53 feet (9 metres) in height. The largest of them were 37.53 feet (11 metres) '.n height, and of these no fewer than six in succession were observed, which followed one another with admir- able regularity. They lifted the corvette as if it had been a whaleboat, then left her wallowing in a deep trough, extending far on either hand. Paris had to mount to the 22nd rung of the shrouds before he attained the level of the crest. On the evening of the same day waves even larger were seen but not measured. Those on board the corvette seem to have agreed that the waves of this 25th October were the largest -mthin Iasl-arv 1. 1901 J K NOWLEDGE 3 their experience. The height of the individual waves was often found to vai-y in the projx>rtion of 1 to 2; it was onlv in vei-y favourable conditions that the average height was 0.7 or O.S of the extreme height. In the open ocean a strong wind soon caused waves of as much as 16.4 feet (o metres). The distane-e from crest to crest was found often to v observable in the interdigital eminences, yet they are much smaller and less distinct than in ordinary monkeys; the same being the case with the ulnar eminence. The radial pattern, at the inner side of the thumb is, however, practically wanting, owing doubtless to the absence of that digit. It will further be noticed from an examination of the figure tliat elsewhere on the palm, not even excepting the fingers, the general arrangement of the ridges is longitudinal. Since the hands of the spider-monkeys are, as already mentioned, largely used in a hook-like ni;uiner during the arboreal evolutions of those active creatures, it would seem at first sight that the arrangement of the ridges precisely controverts what has been said above as to their being pai'allcl with the long axis of the object grasped. But the palms of even these monkeys, as is indicated by the numerous creases, are evidently much folded laterally; and it must also be borne in mind that an equally important function of the hand is the plucking and holding of spherical or sub-spherical fruits. And for such a combination of functions the mode of arrange- ment of the ridges is doubtless the one that is most suitable. If the ridges were transverse the fruit would very probably have a tendency to slip out of the hand on one side of the other; but this is clearly prevented by the longitudinal arrangement. The above ai'e the chief modifications displayed by the palm-prints of monkeys ; and it may bo added that a very similar general plan of ai'rangement of the papillary ridges and grooves obtains on the sole of the foot of these animaJs, subject, however, to such modifi- cation as is necessary for the different function of the foot as compared with the hand. But in some at least of their allies, the lemuroids, as represented by the true Icnjurs of Madagascar, the galagos and pottos of Africa, and the lorises and tarsier of A.sia, a very curious dc- pai'turc from this arrangement obtains. In regard to the true lemurs it is generally stated that on the outside of the palm of the hand and under the base of the fingers are situated fleshy pads, giving them greater grasping power. This, however, is scarcely an adequate statement of the true state of the case. Fig. 5 shows 'h Fio. — Riglit Palm-print ol' Keil-fronted Lemur (Lemur rvjifruns.) the palm-impression of the icd-f rented lemur-, a well- known Malagasy species. In this it will be seen that the balls of the digits are expanded into largo convex circvdar pads upon which are a number of papillary ridges; but instead of these ridges covering the whole surface of the pads, they are interrupted by an irregular nei>work of relatively large canals, producing the white lines in the impression. On the palm of the hand are seen the three interdigital eminences of the monkey's hand, together with a large radial and a somewhat 6 KNOWLEDGE. [January 1, 1901. smaller ulnar eraiuence. The radial emineuoe is, how- ever, divided into two portions by a deep groove, and on all five eminences are observable the usual papillary ridges and gi-ooves traversed by the afore- said irregulai" network of grooves. On the palmar aspect of the second joint of the Angel's, and on such portion of the centre of the palm as exhibits an impression, the papillai'y, ridges, instead of being uni- formly distributed in regi-ilar lines, ai'e restricted to certain small pustule-like eminences, on which, however, the linear arrangement is distinctly visible with the aid of a lens. And if it had been possible to obtain an impression of the basal joints of the fingers, a similar pattern would doubtless have been noticeable there also. Whether the curious arrangement of canals characteristic of the palm of the red-fronted lemur, or a modification thereof, obtains in all the true lemui's, must await the acquisition of additional fi-esh specimens of the hand; but in that species at all events it seems certain that these pads must have a kind of sucker-like action, which greatly increases the firmness of their owner's hold on the boughs it grasps. Apparently this type of palm-structure culminates in the curious little tarsier of the Malay Islands, in which the long and slender toes terminate in round sucker-like disks; similar disks occiu'ring on the toes of the hind-foot. Unfortunately I have had no oppor- tunity of taking the palm-impression of a recently deceased tarsier, and it will probably be long before such a chance occurs, so that I can say nothing as to the mode of arrangement of the papillary ridges. It may be added that the finger and toe-pads of tliose curious lizards commonly known as geckos eve likewise modified into adhesive disks. But in this case the sucking action is caused by the skin being raised into a series of parallel plates, and as palmar eminences, as well as papillary ridges, are wanting, the stiiicture is not apparently strictly comparable with what obtains in the tarsier and the lemurs. But even the foregoing by no means exhausts the subject of palmar and plantar eminences. Anyone of my readers who takes the trouble to examine the feet of a cat. a dog, or a rabbit will find a number of bare elevated pads, covered with rough granular skin, inter- spersed among the generally haii-y surface. In all cases, both in the fore and hind limb, one of these bare pads will be found occupying the lower surface of the terminal joint of each toe, lying immediately below the claw. And it will be quite obvious that these correspond to the pattern-bearing eminences occupying the balls of the thumb and fingers of the monkey. In regard to the pads on the palm and sole, these are subject to some degree of variation in the carnivora, and they may sometimes coalesce to such a degree that their original relations are more or less obscured. But in some of these animals* three distinct pads are obsei-vable in the fore- foot corresponding in position with the interdigital eminences of the monkey's palm. Continuing the semi- circle formed by these three is a fourth pad, repre- senting the radial eminence of the monkey, while further down on the palm is one corresponding to the ulnai- eminence of the latter; a small additional pad being irtercalated between the radial and ulnar. It is thus fully demonstrated that the pads on the fore-foot of the dog and the cat con-espond with the * Those who are interested in the subject may turn to the figure of the foot-pads of the hn.mng, giren by the late' Professor MiTart on page 158 of the Proceedings of the Zo^Io^nial Societv for the Tear 1882. • ' pattern-bearing eminences of the monkey's palm, and these again with the much less distinctly defined eminences on the human hand. In animals. which use both feet exclusively for walking, it will, however, be obvious that delicate papillary ridges, designed pai'tly for the purpose of obtaining a firm grip of any object seized, and paitly to act as organs of touch, would be perfectly useless. And we accordingly find the papillaiy ridges of man and monkeys rej^laced in the cat, the dog, and the rabbit by granular conical elevations, which have, however, doubtless the same structure, and which are foreshadowed by the pustules on the finger and palm of the lemvtrs. One other point remains to be mentioned. In all the lower monkeys that have been examined both by Dr. Hepburn and myself the pattern of the papillaiy ridges is of the concentric type (as shown in Fig. 1), in which the central ridges are longitudinal and the external ones form broad ellipses. In the chimpanzee, however, and probably also in some or all of the other man-like apes, the pattern on the balls of the fingers is of the form known as the looped type, which is of common occuiTence in the fingers of the human hand. On the finger-tips of man alone occiars the still more complicated whorled type. The explanation of the characters of these two latter types may be reserved for an article devoted to human finger-prints ; and it will accordingly sufiice on this occasion to record the fact that even in such a minute detail as the aiTangement of the lines on the fingers of the man-like apes and man stand apart from their kindred, and that in man alone is the most complicated type ever developed, although even in him it is comparatively rare. PHOTOGRAPHY "IN NATURAL COLOURS," BY THE MCDONOUGH-JOLY PROCESS. By H. Snowden Ward, f.k.p.s., Editor of The Photogram. In the present state of scientific knowledge, and in writing for the readers of Knowledge itself, it is un- necessary to say anything about the general history of attempts to solve the problem of " photogi-aphy in tho colours of nature." It may be well, however, to briefly outline tlie history of the process now known as the McDoiiough-Joly, and perhaps, even before beginning the history, to explain why I write of an old process at this particular time. The reason is that this process has only just reached the point of thorough practical bility, and that in a few months it ought to be possible for every photographer to obtain, at a very small cost, the necessary apparatus and materials. I have no brief on behalf of this particular process, and I realise the great beauty and value — if you will, the superior beauty and value — of the resnlts of tJie triple-film supeqaosition process. The two methods supplement rather than antagonise each other, and each has its advantages. Those claimed for the McDonough- Joly process are Wiat it requires the smallest possible alteration of existing apparatus, no change in existing methods, and necessitates only one exposure, with one lens, on one plate, to secure the triple colour-record. Fm-ther, from the negative so made, a single trans- pai'ency can be prepared (in the same way as making an ordinai-y lantern-slide) for lantern projection, and a single piinting by well-known processes will give a colour-print on paper. To project the transparency in coloiu'K, a coloui'-acrccn is necessary, and to make the print in colour it is necessary that the photographic sensitive surface shall have been laid by the manufac- January 1, 1901.] KNOWLEDGE. tiu-er of the paper ou a substratum ruled with alternate Hues of red, green aoid blue, as will be explained later. The history of the process is iuterestiug luid even romautic; for ouo of the ep. 433- 462, pi. vii.) contains an interesting paper on " Stridulating Organs in Coleoptera," by Mr. C. J. Gahan. His re- searches confirm Darwin's observations in the "Descent of Man," that these organs are "wonderfully diversified in position," though their structure is usually simj>le, consisting of a series of fine striations over which- a file- like area or a rasping edge, formed by some neighbouring part of the exoskeleton, plays. In many cases the striated area is divided into a coarser or finer portion, whence it appears that notes of varying jiitch can be produced. The J*;^ best known of " musical beetles " are probably the long- horns, which rub the movable prothorax over a striated area on the mesonotum ; but stridulating organs may occur on the head, legs, wing-cases, and hind-body. It is remarkable that a sinjilar organ may be developed in widely different families in exactly the same position on the beetle's body. Although these organs ai-e often equally developed in both sexes, Mr. Gahan inclines to the theory of sexual selection as their probable explanation. But the presence of " musical boxes " on the grubs of beetles is much more puzzling, especially as they occur in groups that live underground (as the chafers and dor- beetles), or burrowing in wood (like the stag-beetles and passalids). In these grubs the roughened areas are on the haunches of the middle legs, and the scrapers on the hind-legs ; in the passalid grubs the hind-legs are so reduced that they are useless for anything else than sound- producing. It has been suggested that '' with a number of larvie living close together in the way described, it would be an advantage to each to lie left in undisturbed possession of its barrow. . . . Stridulation acting as a sort of declaration of each individual's rights would tend to jsromote general harmony." — G. H. C. — I < I — ZooLOi'.icAL. — The discovery by Major A. Gibbons of the white, or Burchell's.rhmoeeros (li.sijriiis) to the north of the equator, near Lado, removes one species from the list of animals threatened with impending extermination. Pre- viously, this animal was considered to be practically confined to the region bounded by the Zambesi and Orange Eivers. Among other African animals bordering on extiuctiou is the mountain zebra (Eqiius zebra) of Cape Colony ; it is therefore fortunate that a nearly allied form has been discovered in Angola and the adjacent districts, of which specimens have recently been sent to this country by Mr. W. Penrice. Several of the West African mammals are of archaic types, and it is now urged by Miss A. Carlsson that the two-spotted paradoxure {Naiidiuia hinotata) is nearly related to Antphictis, of the Oligocene of France. Nan- dinia is also peculiar in possessing a kind of rudimentary abdominal pouch, the presence of which has led one writer to suggest that the creature is a marsupial instead of a civet. A paUeontological contribution of much interest is one by Prof. H. F. Osborn in the October number of the American Naturalist, dealing with the question of the relationship of birds to the extinct dinosaurian reptiles. Although it is Considered that many of the resemblances between these groujis are due to adaptation for the upright posture, the author comes to the conclusion that birds are probably an early offshoot from the diu^saiu'ian stock lief ore that ]iosture had been attained by any of its members. It is interesting to find that, according to a paper con- tributed byProf.E.Fraas to the Fnndherichte aus Schwaben, the ancient Romans were well acquainted with the difference between the bison and the wild ox, or aurochs; characteristic statuettes of both species having been discovered. Dr. Fraas refers the bison thus represented to the extinct Bos priicus, although we should have thought it more likely to be identical with the living B. bonassus. The worm-like Balanoejlossus and its kindred form are one of the most interesting groups of invertebrates on account of their relationship to the vertebrates ; therefore every new fact connected with them is of importance. In the Transactions of the New Zealand Institute tor 1899, Prof. Benham records the presence of the above-named genus in New Zealand waters ; while in the Proceedini/s of the Washington Academy for August Mr. W. E. Kitter describes the new genus Harriinania from the Alaskan coast. For the first time in its long career the Zoological Society's menagerie in the Regent's Park has received living examples of the tenrecs {Cerdetida-) of Madagascar, most or all of which have been received on deposit from the Hon. Walter Rothschild. The tenrecs are some of the most curious and jsrimitiveof the insectivorous mammals, and are entirely restricted to Madagascar. Their spiny covering gives them a superficial resemblance to hedgehogs, from which, however, they differ markedly in the form of their teeth, as well as in many other charaeters. Several specimens belong to the common tenrec {Cenfdes ecati- datns), but one indicates a different type.' I'he former show that the stuffed specimens in museums give no adequate idea of the form of these strange animals, whose -■~*^ • o u o O t/) W H u Hi u tn d tn h b: u n o o < <: CO *^r i ■ •••/•'• "••*'♦••.•■'•.•■: •,•■>'•. v.. '-. ••• •; • l... y ; .-f-;-^' \»:. •/♦••••.•■••'.•v.i.'< V- *■■ i •.••, ■ .f ••>.•.•..-•;.•. ••.\vr.;'.. ... ...... •',..;;; r.** -^ . • • • • • ' • • •• .■■.■■" - • •..''",.•■, • ' .•.'^•'-^^■••;;'-V -•:=•' ••v/-:^^-.: ■*'.■' ■ ' / .' ■•^; • ; • *. . ■ - : ■ • • ...•-■ • • • '. Ja.niasv 1, lUOl. KNOWLEDGE. 11 Itoilios iiinv bo ooiiipared to those of infl'itoil globe-fish. Ferhiips the most iiceiiliar feature about tliein is the swollen eonditiou of the hiuilev part of the palate, which is, of course, onlv seen when they yawn- a habit in whi<'!i they Seem fond of induljring. Another animal at the "Zoo "never before exhibited alive in this country is the white ffoiit of the Rocky Mountains, one of the few species of mammals that are while at all seasons. Wo jiurposely allude to this animal by its j>opular name, since naturalists are not in accord as to its proper scii'utiflc title; Eui(lish writers generally calliui; it Haploceruf (or Aploririis), while Americans jirefer Oreainniia. We think the latter are in the right. The German naturalist Horinann Klaatsch has made the interesting discovery that, with the exception of the manlike apes, none of the Old World monkeys possess a muscle corresponding v.ith the one known in human iUiatoniy as the short head of the hii-cpn jlexor cruris. And since the re]>reseutative of the same muscle, under two ditferent moditieations, occurs in the American monkeys, the question whether these are more nearly related to man and the man-like apes than are the ordinary monkeys of the Old World is opened up. — ►.*.< — Intekxational Catalogue of Scientific Literature. — .\t meetings of the council of this important under- taking held on December I'ith and 13th, the object, scope, and organisation as defined by successive conferences held during the last four years were brought into their final form, and aU arrangements were comiileted for the defi- nitive commencement of the work on January 1. The catalogue will at first be issued in annual volumes, but its form and rate of production will necessarily be governed to a great extent by financial considerations. The respousibUity for publication and for the initial expenditure is undertaken by the Koyal Society, and the central bureau will Ix^ in London, while regional bureaux in correspondence thei'ewith will of course be established in all the countries taking part in the undi'rtaking. A comprehensive and elaborate system of classification has been devised with the assent of all the countries interested. PHOTOGRAPHS OF THE CLUSTERS M. 35 AND M VI. 17 GEMINORUM, AND OF NEBULAE IN MONOCEROS. By Isaac Roberts, d.sc, f.r.s. CLUSTRRS M. 35 AND W VL 17 GEMINORUM, AND OF THE STARS AROUND THEM. The pliOtogra|di exhibits the region in the sky between R.A. 6h. Om. i4s. ind K A.tJh. 4m 31)s., and in declination between 23= 34' 0 and 24^ .■')8'-3 north. The area' is, therefore, 4m. l-5s. in extent from jireccdirKj to /(illowinij, and P 24'3 from north to south. Scale, one millimetre to thirty seconds of arc. Co-ordinates of the fiducial sj,ars marked with dots for the epoch 1900: — star (.) D.M. No. 109.5 Zone + 23'' E.i. Ch. Om. 45 la. Dec. N. 24° 19 .i. Mag. 87. Star I..) I> M. No. 12'9 Zone + 2.3° B.A. 6h. im. 4-2s. Dec. N. ll" .W .5. Maf. H-i. Stir ( . I D.M. No. 1135 Zone + 21' K.A. 61i .iiii. Il-2s. Dec. N. 2f 1:!' 3. Must. 8-4. References. N.G.C. 2168. G.C. 1360. h 'ill. Rosse, OU. of Neh. and CI., p. ->2.' Lassell, Afem. R.A.S., Vol. XXIIl '. [>. r,9 LB. Ph'.los. pi. i;i, p. 63, y VI. 17, O.C. No. IS.'il. The photograph was taken with the 20-inch reflector on January 20th, 1900, between .sidereal time 41i. 12m. and oh. 42m., with an exposure of the plate during ninety minutes; and the stars are depicted (o about 17th magnitude. The cluster M. 35 is the large palcli of scattered bright and faint stars on the luirt/i ftilhtwiiKj side of the centre, and 111 VI. 17 is the small cluster on the .<:iutth iirecfding side. Both the clusters and tiic stars .surrounding them present to view in a striking manner numerous curves and lines of stars with void spaces between them, which enable us to view the dark- ness of space bcvoiul the dolnctir stellar universe of which the solar system forms a relatively insignificant point. Many astronomers have tacitly adopted the assumption that the stars extend indefinitely into the expanse of space, but that the reason they cannot be seen is the absence of sufficient telescopic power to reveal the very feeble light of stars that are beyond the range limit of all existing telescopes. But the evidence obtained by the aid of photograph)' during the past twelve years strongly indicates, if it does not demonstrate, that those vacant spaces which are visible on photographs tint have been exposed to the sky during intervals of seven to twelve hours are really void of stars. This inference is based upon the fact that photograplis have been taken of identically the same areas in the sky but with exposures of only ninety minutes show the same stai-s, including those of the faintest magnitude, that were shown on the plates exposed up to twelve hours. Therc- foro wo arc ju.stificd (by our present knowledge) in adopting the inference tliab no fainter stars exist, and that the universe which includes all the stars and Uie nebulosity of the Milkij Wat/ is limited in extent, and that it may bo considered as a separate and di.stiiict aggregation of stars and of material of which stars are made independently of other similar stellar aggregations which may exist in the inconceivable expanse of space beyond the Mill-y Way. This view, based as it is on credible evidence, would reduce the whole of the solar system, including the planets and satellites, to a mere speck i-elatively with the Galactic universe alone, and relatively with the others that may be beyond, incon- ceivably small — a microscopic speck. What then about the earth, which wo naturally look upon as a world of great importance? Important of course it is to the million foi-ms of life that exist upon it, ranging between the monad and the elephant, or the whale, or man, but voi-y small relatively with the solar system and insigni- ficant relatively with the Galactic universe. Some minds arc slowly developing and forming con- ceptioits which in time will enable them to appreciate the grandeur of the views of nature as they arc revealed to us by recent researches in astronomical and in other branches of science; but general enlightenment inu.'-t neccssai'ily be slow, for tho propagation of ancient ob- scurantist ideas oppose and greatly retard progress in the development of reason founded upon a basis more sub- stantial than tho waking dreams of obscurantists. NEBULA IN MONOCEROS. Tho photogi-aph exhibits the nebulse and the region surrounding "them between R.A. 6h. 24m. 7s. and R.A. 6b. 28m. Os., and in declination between 9" 12'-4 and 10° 36'-l north. The sky area represented is, therefore, 3m. 53s. in extent from precedhui to f<>IIoinnfj,iind 1° 23'-7 from north to south. Scale, one millimetre to thirty seconds of arc. Co-ordinates of the fiducial stars marked with dots for the epoch 1900: — Sl.ar (.) D.M. No, 1:59 Zone 10' K.A. Oh. 25m. 3n-4.s. Dec. N. 10^ 0 -5. St.ar*'('!.T D.'m. N... 1171 Zone W K.A. Oh. 3-m. lS-.3«. Dec. N. 10° 14'-1. star ('.") T)..U. No. 1172 Zone 10° B.A. Oh. 27n). 32-89. Dec. N. 10" 23'1. ' MaV- 87. 12 KNOWLEDGE. [Jaxuaby 1, 1901. References. N.G.C. 2245-47. Index Catalogue No. 446-7. The photograph was taken with the 20-inch reflector on March 1st, 1900, between sidereal time 6h. 28m., and 9h. 15m., with an exposure of the plate during two hours and forty-seven minutes. The star marked witli two dots (,.) 18 y IV. o, N.G.C. No. 2245, and it is surrounded by faint nebulosity. The st.ar marked with three dots is described as a nebulous .star ; and so also is the bright star, at a. distance from it on the north precedinrj side, described as a nebulous star of lOtli magnitude (Index Catalogue No. 446), but it is shown on the negative to be surrounded by extensive nebulosity with an axea void of stai-s extending towards the south and soiith fvUowiny directions. The star marked with one dot is apparently involved in the large nebula near the centre of the photograph, and on the preceding side of the star is a dark tortuous rift similar in character to tint shi.iwn on the photn^-rapli of IjJ JV. 41 !^aL;ittarii and on others. The rifts j^i'ove that the nebuloe are not globular masses, but are like clouds with relatively small depths, and that we can see through them into the darkness of space beyond. There are also very noticeable areas void of stars in the region surrounding the nebulfe here described ; and the lines and curves of stars are numerous in this region. CONSTELLATION STUDIES. By E. Walter Maunder, f.r.a.s. I.— THE NORTH CIRCUMPOLAR STARS. The workman is nothing without his tools. For the asti-onomer in general these are his telescopes ; his transit circle ; his equatorials. But the fathers of the science had none of these, and they supplied the want by making themselves thoroughly acquainted with the groupings of the stars. The naked-eye astronomer of to-day is compelled to follow their example. The stars are his reference points and he must know them thoroughly ; he cannot know them too well, and the more complete and exact his acquaintance with them, the better he is equipped for his work. It is by the stars that he marks the beginning and ending of a meteor's flight; by the stars he lays down the windings and channels of the Milky Way, or the soft contours of the Zodiacal Light. I have felt it, thefefore, necessary to follow my little note^ on the various departments of " Astronomy Without a Telescope ' by a series of " Constellation Studies "; an introduction of the student, I would hope, to that fuller, more intimate acquaintance with the stellar groujsings which continued and careful star-study will soon give to him. When, where, or why, the constellations were designed and their names given them, are questions which have received much attention but which remain without a complete solution. The sources from which light can come on tlicse questions may be divided under four chief heads. First, Folk-lore, or oral tradition. This is a rapidly-vanishing factor, and, on that account, it is the more to be desired that those who are brought in contact with the isolated peoples in the corners of the earth should lose no opportunity of trying to find out what these have noticed about the stars, what special grouj)s they recognise, what names they have given them, and what traditions they have presei-vcd about them. Next, what may bo called documentary evidence; allusions in classical writers, and the astronomical records of India and China. Thirdly, what we may term — to use a populai' and convenient, though somewhat inappi'O- priate expreission — the " Assyriological ' source; the evidence of monuments and tablets recently discovered in the valley of the Euphrates. . This source promises to be the most fruitful and significant, reaching back into a great antiquity, though it has come into our hands but lately. Lastly, there is the evidence of the constellation groups themselves. This internal evidence is necessarily very limited in its character, yet so far as it goes, it is the most important and unmistakable of all; and is especially valuable when it can be applied as a check to assertions or theories based upon external records of either of the three foregoing categories. To follow up any of these researches is also astronomy — " astronomy without a telescope " — although it is not the astronomy of observation. But the material already gathered under these various heads is far toO' wide to be at all adequately dealt with in the present series of papers. All that can be done will be to give occasional brief notes as to the names of star groups and of indi- vidual stars with their most probable meanings. The most important stai's for the student to begin with are those within the circle of " perpetual appari- tion," the circumjjolar stars — those, that is to say, that are within 50° of the north pole of the heavens. A description of these was given in the nmnber of Know- ledge for April, 1900, to which I would make the following additions. The constellations that immediately surround the North Pole are six in number, five of them ancient; the sixth, Camelopardus, or the Giraffe, was added by Hevelius about 1690. There is no place for hesitation as to which of these constellations we should begin with. " He would scan the figured skies, Its brightest gems to tell, Must first direct his mind's eje north. And learn the Bear's stars well " ; the seven stars so well known to our own peasantry as the " Plough'" or " Charles' Wain." Wherever men have taken any notice of the stars at all, these seven have been recognised as a natural groxip, and in earlier ages, being then much nearer to the Pole than now, they were amongst the stars always visible, not only to dwellers in such northern latitudes as our own, but as far south as the tropic of Cancer. It is easy to see how the names of " Plough ' or " Wagon " for these seven stars have arisen ; their natural configuration has suggested them. The three stars below, as we look at the constellation at midnight at this season of the year, suggest just the kind of curve of a plough handle ; and the four above in a rough rectangle, present the plough- share. Or the four stars above may be considered the four wheels of the rude wagon of which the three below represent the heads of the three horses. " Chariot " or " Wagon " the seven stars have been not only in Northern Europe in our own time but in ancient Greece, and still more ancient Babylonia. Aratus writes of the Pole; — " Two lirars Called Wains moved rjund it either in lie place." And Homer says that on the shield of Achilles were " All those stars with which the brows of ample lieaTcn are crowned, Orion all the Pleiades, and ihose seven Atlas got — The close-beamed Hy^ides, the Bear surnamed the Chariot." But how the constellation got the name of the Bear is far harder to explain. The Sanskrit name " Riksha " Jam-aky 1, 1901." KNOWLEDGE. 13 signifies both "Bear" and "Star," that is, " blight " or ■■ shining " one, and the latter word, — very justly applicable to the seven stars, as being pro-cmiucntly the stars, the shining ones of the noithcrn sky, — may perhaps have been punningly represented by the figure of a bear. But this assumes that the title is Aryan in its origin, which is indeed far from certain. In default of a better theory I am mvsclf inclined to think that the three striking paii-s of stars below the Plough suggested the feet of a great plantigrade anijnal. The lesser Bear no doubt obtained its name from the greater, since its principal stars are a distorted and fainter copy of the seven brilliants of its near neighbour. Classical tradition, according to Aratus, held that they were transfen-ed to heaven as a reward for hiding Zeus in Crete, from his cannibal father Kronos, or else the Great Bear is Callisto, one of Zeus's many loves, and Areas the Lesser Boar her son. The seven gi-eat stars in Job, Chap, xxxviii., the patriarch is asked, " Canst thou guide Arcturus with his sons?' " Arcturus " being the erroneous rendering adopted in the A.V. for " Aish ' the " Bier " or the " Assembly.' This star preserves to us, therefore, almost unchanged the name which the constellation bore at the time when the great drama of Job wa.s written. By far the most interesting object in the whole con- stellation to the " astronomer without a telescope " is Mizar with its near comi)anion Alcor, 80 in Flamsteed's enumeration. Mizar is in every way the (ii-st of the double stai"s. Alcor forms with it a. double to the eye; it has a much closer bright companion which rendered it the first double star to be detected in the telescope, it was the first double stai- to be photographed, and it was the first case in which the .spectroscope showetl that the principal star which appears to us even j with the most powerful telescope a,s single is really in XXI XXII XXIII XXIV ANDROMEDA PERSEUS •t N CAMELOPARBUS 1 . • ■ ■ yf . 1301 "^ P*. • 1 \ •^ ) , Wo- o, •S8 AURIGA •>. MX IX " 'X XI IIIA IIA Star Map Xo. 1 ; Xorth Circumpolar Region. of the Plough are now known by the seven first letters of the Greek alphabet, proceeding in order from the front of the ploughshare back to the handle. The ; names which they popularly bear at the present day are as follows: — Alpha is Dubhe. that is, the " bear "; Beta, Merak the " loin ' ; Gamma is Phccda the "thigh''; Delta, the faintest of the seven, is Megrez, " the root of the tail ' ; Epsilon is usually called Alioth ; but whether this name has much authority is not clear; Zeta is Mizar, a " girdle " or" waistcloth — • but this is a comparatively modern appellation ; Eta, the star at the tip of the tail, has the most interesting name of all, since it is called Alkaid or Bcnetna.sch; j the two names together meaning the " chief of the ! daughters of the Bier." It will be remembered that ' itself double. Epsilon Ursao Majoris marks very nearly the place of the radiant point of a shower of Ursid meteors, the date of which is the 30th of Novem- ber. For those a,stronomers who add the opera-glass to naked-eye work, the three stars of the plough handle and their immediate neighbourhood offer many interests ing fields. So, too, the feet of the Bear, the three pairs of stars to which we have already alluded, are also worth studying with this amount of optical aid. The fore foot is" composed of Iota and Kappa, Lambda and Mu mark the next, Nu and Xi the last. Beta and Alpha are, as is well known, commonly called the " Pointers," inasmuch as the straight line drawn through them leads us veiy nearly to the Pole Star, which is about the same distance from Alpha as Alpha 14 KNOWLEDGE. 'January 1, ISOl. is from Eta. The name given it, from its nearness to the Pole, Polaris, is so universall\- applied to it, nowa- days, that there is little need to notice the many Arabic names which it has borne. An opera-glass, however, shows us other fainter stars yet neai-er the Pole, of which the chief is Lambda Ursae Minoris, just on the limit of unassisted vision, whilst Groombridge 1119 is fainter still. Three other stars, visible to the naked eye, may be nientioned as within 3},° of the Pole ; Cephei 51, a designation which i*- owes to Ilevelius, as it lies within the boundaries of Ursa Minor as the constellation IS usually drawn nowadaj's ; Delta Ursae Minoris ; and Bradley 3147. This little group of stars, though not attractive to the sight, is of the utmost importance astronomically, since its components enable the pro- fessional astronomer to test the accui-ac^- with which ■his transit instniment points to the north at intervals of about two hours. <• .-' 'The ]\Iidniglit Sky for London, 1001, Jamiary .".. Beta and Gamma are the only two other conspicuous stars of the constellation. Beta was once the Pole Star, or at any rate divided the title role 'with Kappa Draconis, and hence bears the name Kochab, '' The Star," that is to say, the Northern or Pole Star. Gamma is a wide double star to the e3'e, Al Fai-kadain. the " calves," usually written Pherkad on our globes. The constellation is the seat of several of the minor radiants. In September, there is one from the neigh- bourhood of 51 Cephei; in April, there is another from near Ganuna Ursae Minoris. Between the two Bears, and almost encircling the Lesser, is a long winding stream of stai-s, making up the constellation of the Dragon. It is certainly one of the most ancient of all, and is believed bv many to be the crooked .serpent of Job, xxvi. 13. Alpha of this constellation, now generally called Thuban, i.e., " Dragon," and situated midway between Gamma of the Lesser Bear and Zeta the Greater, was the original Pole Star of the heavens when the constellations were mapped out, a pre-eminence it must have held for over 2000 years. "Within this constellation also is the pole of the ecliptic, almost in the centre of the great loop made by the Dragon's folds. At midnight on New Year's Day, the Dragon's head reaches down almost to the northern horizon, two bright stars, Gamma and Beta, marking the top of its head. Of these the more westerly is of a rich orange tint, and is the zenith star of Greenwich, and as such was specially observed by Flamsteed, Bradley, and Airy, the second of whom made his discovery of the aberration of light in connection with it. Three staa's, Xi, Nu, and Mu, make up the jaw, Mu being at the snout. Nu, the faintest of the three, is an opera-glass double. Why this coiLstellation got its fearsome symbol is not clear. It is true that the Dragon or snake was amongst all ancient nations used to symbolise the powers of evil, of darkness, or of chaos. But that gives us no explanation why a constellation, far from being the least beautiful and conspicuous, has been chosen to convey this idea of darkness ; still less why such a symbol should have been planted at the vei-y crown of the celestial sphere. From Epsilon in the Great Bear a line through Polaris leads us to a small constellation, yet one of the most easily recognisable in the sky, Cassiopeia, the " Lady on her Throne,'' her prineipaJ stai-s, five in number, suggesting a W freely scrawled. The constellation at this time is west of the Pole, the highest star is Epsilon, then following the other points of the W in order, we have Delta, Gamma, Alpha, Beta. The only stars of the five which in modern days are often referred to by their Arabic names are Alpha, Schedar or "Breast"; and Beta, Caph or " Hand,'' or possibly in some allu.sion to her husband Cepheus who stands by her side. The latter forms a larger but much less conspicuous con- stellation, lying between Cassiopeia and the Dragon, its foiu- chief middle stars foi-ming a lozenge; the point of the lozenge most remote from Cassiopeia is Alpha, Aldei^amin, the " right arm,' the only one commonly referred to now by its Arabic name. Delta is one of the most interesting of the naked-eye short period variables. Cepheus and Cassiopeia are especially interesting since they with three more southern constellations make up a recognised and unmistakable story pictured in the sky ; a clear proof that the work of original constel- lation making was deliberate and not haphazard, and that the legends there represcntetl w^jre in existence before the star groups were made. Brown argues justly that Cepheus is manifestly a non-Hellenic sovereign. He is indeed often spoken of as Ethiopian, but the Etliiopia there meant is not Nubia or Abyssinia, but the Euphra- tcan " Cush.'' Hence there is no justification for those loo precise artists and poets who have represented poor persecuted Andromeda as a sable beauty, " black " if '■' comely." Cassiopeia is a constellation that well repays opera glass scrutiny, and it also furnishes to the naked-eye astronomer several important meteor radiants, of which one from near Delta deserves especial notice, and it is an especial favourable neighbourhood in which to com- mence the study of the Milky \Yay, since the constel- lation passes through our English _zenith. It is most famous historically from the appearance of the cele- brated Nova of "1572 — the "Pilgrim Star" — which formed vei^ nearly the fourth point cf tne squai-e, or rather rhomlus, of which Alpha, Beta, and Gammi mark the other three points. Camelopardus is a great straggling constel'ation, all the stars of which are faint, which lies between Ursa Major and Cassiopeia, and stretches upwards almost to the Pole. Janixrv 1, 1901. KNOWLEDGE. Hcttrrs. [The Editors do not hold themselves responsible for the opinioug or statements of correspondents.] IS HUMAN LIFE rOSSIBLE UN OTHER PLANETS? TO THE EDITORS OF KNOWLEDGE. Sirs, — I have just tome acro.ss a jnissaije iii Grant Allen's little l>iiok, " Tbe Eritish Barbarians," in which he states that •' i>lanetosco|iists " are agreed that there is no form of livin^r ereature iu any of the planets that can he called •' human," because the j>hysieal conditions are in all probability so different from those on this planet that the life which probably does exist there, as liere, will have followed a very different course of development or evolution. I should be very glad if you could inform me in Knowledge whether this statement of the views of those who have made a special study of the planets is correct. I had a itotion that it was considered that the physical conditions of ilars (e.g., so far as they can be known or guessed at) are so like those of this earth as to make it prob;i.ble that human beings may be living there. Of course I know tliat a scientific man would be very reluctant to commit himself to an opinion on a question for the solution of which there is so little evidence avail- able as there is for this question of possible human life elsewhere than on this earth ; and for that vei-y reason I thought Grant Allen's statement was too definite and sweeping. Churchstantou Rectorv, Akxold D. Taylor. Honiton, October Slst, 1900. PHOTOGRAPHIC SEARCH FUR THE LEONIDS. Mr. J. Maclair iJoraston watched for the Leonids on November 14th, from I2h. to 14h. ; -5 meteors were seen — 3 of them being Taurids, and 2 probably Leo Minorids. "The result was that no true Leonids appeared." Mr. Boraston also exposed a plate from 13h. 15m. until I4h. The star trails are not, however, true curves, but show slight irregularities, for which Mr. Boraston enquires the cause. We have examined the photograph scut, and the irregularities are manifestly due to small motions of the camera.— E. W. M. CONSTITUENTS OF THE SUN. "Nemo" enquires whether the experiments of Prof. Janssen, conducted at the summit of Mont Blanc, has not proved that oxygen is wanting iu the suu. No ; Prof. Janssen showed that the !',reat absorption bands given by the oxygen iu our atinosjihere are not also given by alisorptiou iu the solar atmosjihere. But the temperatures of the atmospheres of the two bodies are so entirely different that this is no criterion. It simply shows that oxygen does not exist iu the sun at terrestrial temperatures. " Nemo " also finds the prominences an extremely striking feature in the dark lines of calcium, as seen on a photograph of the solar spectrum, and asks " Is it not then safe to suppose that they are either wholly oi' partially due to incandescent calcium vapour instead of hydrogen, as it is usually stated ? " Certainly they are jiartially due to calcium, even largely so. But their striking relief on the H and K lines is due to the great breadth and darkness ot the corresponding Fraunhofer lines of the solar spectrum. They are bril- liantly seen on the hydrogen lines, notwithstanding that the dark lines of hydrogen by no means ftiraish so good a background for them. — E. W. M. jfloticcs of Boofes. '• AT.Mosi'iir.iuc H.voiATioN. " A Koscarch comiucted at the AUeHbeny Observatory ami ,-it Providence, U.I., by Prof. Frank W. Very.— 'I'hi.s research took its origin in a proljlcni suggested l>y Prof. Cleveland Alilio to Prof. \'ery in IH'.n, as to whether absorption is the absohitc inverse. of radiation for n.ascs. It deals with a subject intimately connected witli that which Air. "W. E. Wilson takes up in his Daramona Observations, lately published, but whereas Mr. Wilson has to do with the radiation from gases at the enormous temperature of the sun's surface, Prof. Very tries to determine the absolute radiation in calories from a unit mass of gas at given temperature and density and at ordinary temperatures, not when burning, not when electrified, but when simply heated. The difficulties of the problem arc very gieat, for, as Prof. Very says, " The investigator here is dealing with the invisil)Ie and the evanescent. In an optical apparatus a little stray liglit immediately attracts attention, and we proceed to trace it to its source with our eyes o])en. In our study of feeble invisible radiations, on the other hand, we grope in the dark, and only succeed in eliminating the unwelcome extraneous rays after innumerable trials and errors.'' It is quite impo.»sible here to give any account of the methods of research or of all the results obtained ; we must confine ourselves to but a few points which appear to bear directly on .solar physics. As an absorbent of terrestrial r.adiation, arjucous va])OHr is' very much more efficient than any other atmospheric ingredient ; but as radiators when in large mas.ses, the substances composing the atmosphere do not differ so widely as might be supposed, since the facility with which a highly radiative vapour parts with its heat is largely annulled by self absorption in its deep layers of its own radiations, and since in gases heat is transferred from molecule to molecule with the greatest ease, it is the feebly radiative molecules which act as radiators, excejit iu the com- paratively tluu outer layers. The depth of gas which gives ma.ximum radiation at short range is an insignificant quality compared with atmospheric dimensions, and radiation from either the atmosphere of the earth or the solar chromo- sphere is a superficial phenomenon, even when the masses of heated gas measure thousands of miles iu thickness. The fineness of the chromospheric lines in the solar spectrum, although the shifts of the Fraunhofer lines indicate pressures of many atmospheres at the base of the chromosphere, is a sufficient demonstration that only the outer layers radiate. Prof. Very also confirms and extends Air. Evershed's results on the heating of iodine and its kindred vapours, that the light emitted by these glowing vapours appears to give a ])erfectly continuous spectrum while tile corresponding absorptiou-spectra are selective. "Thus there is no such close relation between emission and absori)tion as isimphed by Kirchotf's law of radiating bodies. There seems, however, to be a general relation between the total absorbing and radiating power for the visible rays.'' These points seem to have a very clo.se bearing on the ([uestion of the relation between the Fraunhofer and " Flash " spectra. •'TiiK Kiddle ok tiii'. U.nivkusk." By Ernst Haeckel. English edition. (Rationalist Press Association.) (is. net. — However unwiUing we may bo to accejitsoine of the conclusions arrived at iu this book, it is impossible not to admire the man who has written it. Towards the close of a life devoted to science he has, in "The Riddle of the Univer.se,'' summed up in popular form his views on all the great questions that ad'ect mankind. His wealth of accumnlated knowledge enables him to sweep from one great problem to another with astonishing ease and power. He first briefly summarises the evidence of evolution. Comparative anatomy and physiology alike forbid us to separate man from the apes. Embryology puts it beyond a doubt that men have been by gradual stages evolved from a simple type of organism. After an enthusiastic appreciation of the work of Darwin, he discusses the " Nature of the Soul, " writing as a convinced monist, to whom dualism in any form is an abomination. The soul cannot exist apart from the body, nor the boily apart from the soul. " Athanatism,' the im- mortality of the soul, is inconsistent with the very principle of monism. The individual perishes, but according to the "law of substance " matter is eternal. The chemical law of substance must be us^ociated wiih the phy.siciil law, the conservation of 16 KNOWLEDGE. [January 1, 1901. energy. The sum of matter and the sum of force in the universe are unchangeable. The law of energy holds true in physiology. The growth, sensation, and movement of living organisms depend on the conversion of the potential energy stored in their food into kinetic energy. We now proceed to the monistic cosmogony. " The world (i.(., apparently, the universe) has no beginning and no end." The world and all living organisms upon it have been evolved. There is an absolute unity of nature. We cannot deny the affinity of the organic to the inorganic : the elements contained in both are the same. This monistic [ihilosophy leads inevitably to Pantheism. Even in Prof. Haeckel's statement of the theory of evolution there is much to criticise. He has not got rid of Lamarckism. Without even discussing the subject he decides that instincts are due to inherited habit, appealing to Darwin, though Darwin maintained that most instincts had quite a different origin. Moreover, we want to know on what lines evolution is pro- ceeding among civilized races ; whether, for instance, .science and wealth are bringing about physical degeneration. On this he is silent. Intellectual freedom, he maintains, would bring about pi'iH/ress in science and civilhatiim, but as to further evohttion he is silent. He exaggerates the achievements of science. We know nothing about the origin of matter ; yet he stoutly maintains that the universe has had no beginning. In the concluding pages, however, he speaks more reasonably : " We grant at onee that the innermost character of nature is as little understood as it was by Anaximander." One more criticism. He attacks religion with an acrimony that is out of place in a scientific work. His hatred of it blinds him to the fact that the evolution of civilized man (of Professor Haeckel himself, with Lis strong love of truth and justice) would not have been possible without the alliance of religion with morality. A life of controversy has left its mark on Professor Haeckel. There are subjects on which he cannot touch without losing his patience, and sometimes even his dignity. "The Royal Observatory, Greexwicii : A Glance at its History and Work." By E. Walter IMaunder, f.h.a.s. (Re- ligious Tract Society.) Illustrated. .5s. — To the public at large the Royal Observatory is forbidden ground, and we are therefore esjiecially grateful for this authoritative account of our national observatory and its work. The story of the foundation and development of the Observatory forms an imjiortant chapter in the history of science, and it is here admirably told from first-hand sources in a popuLar manner, but with sufficient fulness to form a valuable work of reference. Commencing with the pathetic figure of Flamsteed — without assistance or instruments other than he chose to provide out of his meagre salary of £100 a year — the gradual acquisition of buildings, instruments, and staff under the rule of succeeding Astronomers-Royal is traced step by step ; and, finally, the reader is conducted through the various departments as they exist to-day. Doubtless many who believe that to be a pro- fessional astronomer is to sit at the eye-end of a telescope and admire the glories of the heavens will be disillusioned on reading this book. The busy hive of workers, mostly employed in laborious calculations at their desks, forms quite another picture, but the author, who is so well known to our readers, has the skill to reveal the inner beauties of even this very serious side of astronomical work. It is made quite clear also that it is not to such an institution as that at Greenwich that we must look for " discoveries " in astronomical science, the aim being more especi- ally to cultivate those branches of work which demand continuous observations extending over many years, and which cannot therefore be left to the efforts of amateurs. It is well to recall the fact that the Royal Observatory was founded primarily, and has since been maintained, for the strictly jjractical purpose of assisting navigation, by obtaining a better knowledge of the motions of the moon and of the positions of the stars for appli- cation to the determination of longitude at sea. Expansion in various directions, however, was inevitable, but assistance to navigation has always been the first object of the work of the Observatory. The book is brightly written throughout, and gives much valuable information in an unobtrusive way, not only with reference to this jiarticular observatory, but on a great variety of astronomical subjects. It is beautifully illus- trated, with ])ortraits of the eight Astronomers-Kojal, and many photographs of instruments and observatories. To those interested in astronomy the book is an excellent substitute for a personal visit to the Observatory, and even those who may obtain the great privilege of a visit will find that they will see a great deal more by having first learned what to look for. " Photoguams of the Year 1900." Compiled by the Editors and Staff of the PJiofoiji-ain assisted by A. C. R. Carter. 3s. (Dawbarn and Ward.) — This comprehensive annual should be in the hands of every photographer, both for his pleasure and his profit. In its well-arranged pages are produced not merely a good display of all sorts of prints, but also articles by writers who are entitled to speak with authority. These articles are selected with the object of exemplifying opposite views of photography. Hence we have one writer, Herr Ernst Juhl, full of praise for " gum " printing, and expatiating on its possi- bilities in the hands of certain German workers. And, in direct antagonism, an article by Dr. P. H. Emerson, in which he vigorously condemns, not only " gum " printing but also " faking," and he apparently would allow no handwork at all. To this lack of agreement among experts we may obviously assign the variety of grotesque photographs which are accorded prominence in the annual exhibitions. Photographs which arrest the eye solely because they startle, are so frequently held up to admiration for their originality that the multitude of unhappy productions of this kind have already made " artistic photography " the laughing stock of artists. No better instance is wanted than that of a production labelled " In the Marshes," on page 15 of P/intoi/rains of the Year. But perhaps the fact that but few such prints are given in this book is a sign of increasing sanity in photography. " Studies in Fossil Plants." By Dukinfield Henry Scott, M.A., PH.D., F.R.s. Illustrated. (Black.) 7s. (jd. — Botanical readers have long since learned that anything which proceeds from Dr. Scott's pen demands their best attention. The volume before us, the latest addition to the rapidly increasing literature of " Fossil Botany," is, in every respect, up to the high standard which the author has attained in his previous works. Fossil plants, until recently, have received but slight atten- tion from the botanist, and for the geologist they have had but little interest, except as characteristic marks by which certain strata can be recognised. Among living English botanists who have studied these records of the plant life of past ages, perhaps none have done more important work than the author of this volume, and he is, therefore, peculiarly qualified to present us with an account of the present condition of our knowledge of the subject. Taking for his text the classic phrase in which Count Solms- Laubach staled the object of the study of fossil plants, " the completion of the natural system," Dr. Scott records " those results of paheobotanical enquiry which appear to be of funda- mental importance from the point of view of the botanist." These are found almost entirely in the two sub-kingdoms ' Pteridophyta " and " Gymnospermoe," which alone ai-e dealt with. The fossils considered are such as are " well- characterised " ; more doubtful specimens being wisely dis- regarded. The treatment of the subject is exceedingly clear, and the work cannot fail to be of absorbing interest to the student of living plants who desires a stereoscopic view of the vegetable life of the globe. The capital illustrations which abound, show the remarkable fidelity with which even minute details of the structure of vascular plants have been preserved by petrifaction, and add considerably to the value of the work to the palaeobotanical reader. "Report op the Kite Observations of 1898 by the Dli'art.ment of Agru'UlturEjU.S.A." — The observations were made with Box Kites, at seventeen stations in North America. The mean rate of diminution of temperature with increase of altitude, as determined from 1217 ascensions and 3838 observa- tions, taken at elevations of 1000 feet or more, was 5.0° for each lOOfl feet. The largest gradient, 1A° per 1000 feet, was found up to 10(10 feet, and thereafter there was a steady decrease up to 5000 feet, the rate of decrease becoming less as the altitude increased. The relative humidities at and above the earth's surface differed little except at 7000 feet, where the surface humidity w.as 11 per cent, less than that above. There was a steady but by no means uniform decrease of vapour pressure with increase of altitude. January 1, 1001. "" KNOWLEDGE 17 "Anntal Rkport of the Paris Observatory." — Of lato years the Paris Observatory has given in each annual report a very beautiful and practical specimen of the work accomplished, in a heliogravure of the moon, photographed by MM. Lewy and Puiseux, with the Grand Equatorial Coudc. The plate this year was taken ou ISO;'. February, 6d. U').5h., when the moon was aged l>d. 8.8h.. and the Mare SereniUitis was half in shadow, its western w:ill showing very dimly against the skj'. The chief point of interest, indeed, in the report, relates to the great lunar photographs, and especially to the giant presentations of l.l^Hm. of the moon in the first and last quarter, exhibited at the Paris Exhibition. Besides the work of the great lunar atlas, and the other routine observations, connected with the meridian and astrographic departments, M. Hamy has conducted a series of interference measures with the object of determining the wave-lengths of a certain number of standard points in the spectrum. "The Path of the Six : ItsOrhit and Period of Revo- lution DEMONSTRATEn." With an Exposure of the Fallacy of the Precession of the Equinoxes. By William Sande- man, f.C.a. (Simpkin.) — The phenomena produced by the rotation of the earth on its axis in 2-t hours, could also be ex- plained by a rotation of the entire heavens on a similar axis in a similar time. So the phenomena produced by the revolution of the earth round the sun in a year could also be produced by the revolution of the sun round the earth. We have plenty of paradoxers to uphold both doctrines. The gross improbability of their assumptions does not strike them, and they arc either ignorant of those facts which are irreconcilable with their theories, or they have not sufficient discernment to see how they bear upon them. Mr. Sandeman falls into an error, precisely analogous in its character, but dealing with a somewhat more recondite question. He refers the rotation of the axis of the earth in the precessional cycle of nearly 26,0(iO years to a revolution of the sun and the entire solar system in a similar period. The paradox is therefore practically the same in nature as those with which the ''flat-earth" and the '-immovable- earth " people have made us so familiar. "Annals of the Lowell Observatokv," Volume 11. — The second volume of the "Annals of the Lowell Observatory" is like the first, sumptuously prepared and fully illustrated. It deals with the two planets Jupiter and Mars : the first was observed in 1894 and 18'J5, the latter in 1896 and 18',I7. The observations of Jupiter itself dealt with the polar flattening, which was found to be 1/16.11, and with refraction in its atmo- sphere. The amount of refraction found was considerable, namely a refraction of 8' of arc in the outer atmosphere. The depth of the atmosphere would appear to be great — 2801) miles is sngge-sted — with a slow decrease in the refractive power and density. But much more attention was given to the satellites, of which a great number of beautiful little drawings are given. Of the satellites, the first was considered to be markedly ellip- tical, being a prolate spheroid, revolving end over end about one of its minor diameters in a period of 13 hours. Of satellite II., Utile could be made out. The third satellite showed a slight ellipticity, but several surface details were detected, which may be de.scribed as a northern belt, crossed occasionally by another line or belt, rarely a central forked belt, and once a southern belt. The fourth satellite also showed a slight ellipticity. Both third and fourth satellites kept the same face always turned towards their primary, whUst the rotation of the first satellite was much more rapid than its revolution. The greater part of the volume is, however, given to the planet Mars, and the re- searches detailed in the first volume of the •' Annals " are continued in this. The meteorology of JIars, it is infeiTed, resembles that of our own earth, except in so far as they are affected by the limited water supply. There appears to be a great transference of moisture from one hemisphere to the other, twice in the course of the Martian year, chiefly by an srial transmission. " Radiation and polar clouds are the more common forms on Mars, cyclonic and conventional clouds are very rare." The observers are inclined to ascribe many of the dark markings to vegetation. " The surface of the planet teems likely to be level, but large raised areas exist in the polar regions. . . . The mean temperature at the poles is likely to be not far below freezing, the contrast between day and night is considerable." Whatever reluctance may be felt to accept the conclusions of the Lowell observers in their fulness, there can be no question that the principle they adojited of making these planetaiy observations as continuously as possible, and not spasmodically, is the right and true one It is the only method, and it is a certain one, for making substantial progress in our knowledge of the conditions of the planets. "Willia.ms and Xorgate's Book Ciucular." — We have received a most useful volume from Messrs. Williams & Norgate, comprising eight monthly issues of their Book Circultir. This l)ublication contains well-writton and critical notes on new and forthcoming books, chiefly Continental. It should be of considerable value to scientific workers. Cataloijfes. — Wehave received useful catalogues of electrical apparatus, from Messrs. W. & J. George, Limited ; of raicrosco|)es and micro.scopic slides, from Mr. (J. Baker : of cabinets, birds' eggs and skins, butterflies and moths, from Messrs. Watkins and Doncaster : of bioscopes and of cinematograph films, from the Warwick Trading Company, Limited ; a pami)hlot on the Kammatograph, from Messrs. Kamm & Co. ; a Radiographic list from ^Messrs. Isenthal & Co. ; and supplementary list of lantern slides from Messrs. Newton & Co. BOOKS KECEIVED. The Progress of Inveiidcm in the Nineteenth Century. By Edward W. Byrn. (New York : Munn & Co.) Illustrated. S3. Report on the Census of Cuba, 1S99. (Washington : Govoriimeut Printing OUice.) Railway Runs in Three Continents. By J. T. Burton Alexander. (Elliot Stock.) 7s. 6d. net. Botany : An Elementary Text for Schools. By L. H. BaUey. (Macmillan.) Illustrated. 6s. Botany. By K. 8. Wisliart, m.a. (The Sclf-Edueator Series.) (Hodder and Stoughton.) Illustrated. 2s. 6d. The Self-Educator in French. Edited by John Adams, M.A., B.sc. (Hodder & Stoughton.) 2s. 6d. One Thousand Objects for the Microscope. By M. C. Cooke, sr.A., LL.D , a.l.s. New Edition. (Warne.) Illustrated. 2s. 6d. All Change. By Wilfred WooUam, M.A. (Elliot Stock.) What is Heat ! and What is Electricity '. By Frederick Hovenden, P L.S., F.O s., F.E.M s. (Chapman & HaU.) Illustrated. 63. A New Practical Method of Learning French Colloquially. By L. B. Meuuier. (Philip & Son.) 28. The Structure and Life History of the Harlequin Fly. By L. C. Miall, F.R.S., and A. R. Hammond, f.l.s. (Clarendon Press.) Illus- trated. 7s. t)d. Hand-Book of Practical Botany. By Dr. E. Sti'asburger. Trans- lated by W. HiUhouse, M.A., F.L.S. 5th Edition. (Swan Sonnenschein.) Illustrated. lUs. 6d. The Romance of the Earth. By A. W. Bickcrton. (Swan Sonnenschein.) Illustrated. 2s. 6d. A School Chemistry. By John Waddcll, B.A., B.sc. (Maemillan.) Illustrated. -Is. net. By Land and SA-i/. By the Ecv. John M. Bacon, M.A., f.e.a.s. (Isbister.) Illustrated. 7s. 6d. Annuaire Astronomique, 1901. Par Camille Flammarion. (Paris; Flammarion.) Illustrated. Ifr. 2.5. Table of Dieisors. By Tliomas Denee. (Mayfair Works.) The Complete Works of John Keats. Edited by H. Buxton Formau. Vol.1. (Glasgow: Gowans & Gray.) Is. net. Table Generate des Publications de la Societe d' Anthropologie de Paris. (Paris : La Soeiete d' Anthropologie ) 6fr. 2'he Story of Thought and Feeling. By Frederick Ryland, M.A. (Newnes.) Is. Jewellery and Trinkets. By .iliee Teague. (Dawbarn & Ward.) Illustrated. 6d. net. The Beacens at a Glance, IMl. Card Calendar. By Arthur Mee, F.B.A.s. 7d. Post free. The Story of Nineteenth Century Science. By Henry Smith Williams, M.D. (Harper and Brothers.) illustrated. 9s. The Principles of MagnHism and Electricity. By P. L. Gray, B.sc. (.\Ietliuen & Co.) 3s. 6cL Lord Lilford : A Memoir by his Sister. (Smith, Elder & Co.) Illustrated. 10s. 6d. Practical Lessons in Metal Turning. By Percival Marshall. (Dawbarn & Ward.) Illustrated. 2s. net. Who's Who, 1901. (A. & C. Black.) 5e. net. Englishmoman's I'ear Book. (A. & C. Black.) 2s. 6d. net. 18 KNOWLEDGE. [January 1, 1901. Conducted by Harey F. Witeerby, f.z.s., m.b.o.u. • Bird Migration in G-eeat Britain and Ireland. — At the meeting of the British Associatiou iu 1806, it will be remembered that the Bird Migration Committee published a most important Digest of the Observations on the Migrations of Birds at Lighthouses and Light-vessels from 1880 to 1887.* This Digest was the work of Mr. W. Eagle Clarke. Important and satisfactory as it was, it was onlv considered as the foundation for future work. Undaunted by the magnitude of his task, which cannot be exaggerated, Mr. Clarke has not only continued his work of systematically tabulating the 100,000 records of the lighthouses, but he has added to this mass of facts many more thousands of observations culled from the voluminous literature published during the period covered by the enquiry. Four vears of incessant toil since the publication of the" Digest enabled Mr. Clarke to gather, sift, and arrange, iu conjunction with the lighthouse re[.)orts, this additional matter, so that the data being now as complete as possible, " the time has arrived when, for the fii'st time in the annals of British Ornithology, it is possible to write an authoritative history of the migration of each British bird." And not only is this possible, but we believe that Mr. Clarke has so far advanced this most important and valuable work that its publication will not now be long delayed. As examples of his method of treating the subject, Mr. Clarke furnished the British Association last year with a summary of details of the various migratory movements of two species — the Song Thrush and the White Wagtail. The following brief abstract of one of these may interest those who have not had an opportunity of reading the original paper : — The MiGE-ATiONS of the Sono Thrush. — The Song Thrush furnishes a most excellent example of the complex nature of the phenomena of bird migration as observed in Great Britain and Ireland. Its various movements cover a period of nearly ten months of the year. Throughout August and more especially in September and October many Thrushes, which have bred here, move southward to winter in warmer climes. At the end of September and during the whole of October great numbers of Thrushes from North- Western Europe invade the north- east coast of Great Britain. Of these foreign-brel birds many proceed south and finally quit our shores, the majority to seek more southern lands, but others to winter iu Ireland. Others, again, remain as winter visitors in Englaud. This immigration of Thrushes from the Con- tinent, unlike that of other species, ceases with the month of October. In the winter (from October to February) we have a difi'erent kind of migration. These movements are * For Summary of this Digest see Knowlkbob, November; 1896, pp. 254—256. entirely due to outbursts of cold or bad weather. At such times immense numbers of Thrushes, both residents and intending winter visitors, rush to the coasts, along which they proceed south and west. If the cold continues many leave the country altogether, while others find refuge iu Ireland. During February and March our own Thrushes, which left us in the autumn to winter in the south, gradually begin to return. Towards the end of March the Thrushes which have wintered in the islands o& the west of Scotland and Ireland take their departure for Northern Europe. Throughout April those that have wintered in the mainland depart as they came, via the north-east coast of Englaud and the east of Scotland. Merged somewhat with this latter movement are the travellers which pass during April and occasionally in May along our eastern seaboard on their way from the south to the north of Europe. These are the main points in the complicated migratory movements of the Song Thrush in Great Britain. All ornithologists will heartily agree with the Migration Committee that "A great debt of gratitude is due to Mr. Clarke for the courage and perseverance which he has shown in grappling with the enormous mass of statistics necessary 1:0 att'ord the results so lucidly and concisely summed up by him." Baird's Sandpiper in Sussex. — A New Bird to the British List. — At the meeting of the British Ornitho- logists' Club, held on November 2Ist, 190O, Mr. Ernst Hartert exhibited a youug female specimen of Baird's Sandpiper {Heteropyqia hairdi). The bird was shot at Eye Harbour, Sussex, on October llth, by Mr. M. J. NicoU. Mr. Nicoll wrote that the flight was like that of the Common Sandpiper for the first few yards, then the bird rose straight in the air for a considerable height, and then dropped suddenly towards the ground. It did this every time it was flushed. Its cry was a shrill twitter, difierent from that of any British species. The bill and legs were jet black. Baird's Sandpiper is au American species. British Form of the Willow Tit {Parus salicarius). — In Knowledge for April, 1898, p. 81, we drew attention to this bird, which Mr. Hartert introduced to the British list from specimens obtained at Finchley. At the Novem- ber meeting of the Biitish Ornithologists' Club, Mr. Hartert announced that he had found a specimen in the collection of Mr. Ticehurst, from St. Leonards, and had recently received fresh skins from Mr. Ruskiu Butterfield, from Hastings. The bird would no doubt be detected in other localities, when British ornithologists were able to distinguish the Willow Tit, with its dull head, from the ordinary Marsh Tit with its glossy crown. Ornithologists will do well to carefully observe Marsh Tits, in the hope of distinguishing the Willow Tit, and thus obtain more evidence regarding the bird in Great Britain. There is a little difficulty about the name of the bird. For those who accept trinominals and unite all the dull-headed forms of the Grey Tits, the Continental Willow Tit would be PariijS montaniig salicarius, and the British form Parus montanns Kleinschmidti ; otherwise the British AVillow Tit might be called Parus Kleinschmidti , since it differs from the Continental form by being slightly smaller and more richly coloured. Those who do not recognize the slight differences of the Continental and British forms of the Tits as worthy of specific rank should call the bird Parus salicarius, and in taking Mr. Saunders' Manual as the standard book on British birds, and following his decisions regarding the Long-tailed Tit and the Coal Tit, we are inclined to call the Willow Tit simply Parus mlicarius. Janiabv 1, 1901.] KNOWLEDGE 19 Tht Bird-t of Yorkshire. — Xl>e Uouornrv Secretary of tlio York- shire Xaturalists' Union annoiiuees tliat Mr. T II. Nelson lias under- taken to continue and complole .Mr. W. Hagle Clarke's work on the "Birds of Yorkshiiv," whiih lia." been partly published in the Transactions of the Yorkshire Naturalists' Union, and the continua- tion of which w^»s interrupted by Mr. Clarke leaving Yorkshire to settle in Edinburgh, l^onsidering the leiiiith of tin\e that Invs elapsed, and the number of records and observations of Y'ortishire birds which hive accumulate.! sinoe Mr. Clarke wrote his last instalment of this work, we think it \inwise to continue the yniblication. Good as we know Mr. Clarke's work to be, such revision is required in bringing it up to date that nothing short of rewriting would be satisfnetovy. Moreorer, Messrs. Oxley Graham and James Packhousc have long been euga;jed on a work on the birds of Yorkshire, tlie manuscript of wliich we miderstaud is now nearly complete. Pectoral Sandpiper at Aldehurcjh (Zoologist, November, 1900, p. 521). Mr. E. C. Arnold records that he shot a specimen of Trini/n maciilala on September 13th last at Aldehurgh, Suffolk. This bird has occurred in England more frequently than any other .Vmerican wader, and has already been recorded four times from Suffolk. All contributions to tJie column, either in the way of notes or photographs, should he foruardcd to Harr'T F. Witherby, at 1, Eliot Place, Blackheath, Kent. THE INSECTS OF THE SEA. B_v Geo. H. Cakpenteh, b.sc.(lond.j, Axsislanl in the Miii>etii)i of Science and Art, Dublin. INTRODUCTORY. Marine insects have been somewhat neglected both by entomologists and by students of the " common objects of the sea^shore." An ai-dent insect-hunter will quickly fill his boxes, as he wanders over the hillside, or sweeps along the thick undergrowth of the woodland, while hours of work along the tidal margin may yield him but a few obscure flies and beetles. And the nattu-alist who finds especial delight in the rock-pool or the wave-swopt beach, is usually so engrossed with his shells or his zoophytes that he does not notice the insects lurking beneath the stones or crawling among the seaweed. Hence so keen a naturalist as the late P. H. Gosso* told his readers forty-five years ago that "of the hun- dreds of thousands of insects known to exist but (ico live in the sea." Even at that date the statement was much under the mark. Leach, Guerin, and Haliday had years before detected and described many of the shore-haunting insects which will be mentioned at length hereafter; while as early as 1822, Eschsholtz had made known the wonderful bugs of the genus Halobates, the only insects whose whole life is spent on the open sea. In 1871, A. S. Packardt mentioned some dozen marine species from the Atlantic and Pacific coasts of North America. References to marine insects in the works of recent writ-ers — Moniez]; and Miall§ for example — show that some scores of kinds probably occur on our own coasts, most of the important orders being represented. And it is likely that the marine insects of the whole world will be found to number some hundreds of species. Still the insects of the sea seem but an insignificant group when we compare them with the well-nigh coiuit- less kinds of insects that inhabit the air and the laiul, two millions according to the lowest recent estimate, * "Manual of Marine Zoology for the British Isles," Part 1. p. 178. London, 1855. t " On Insects inhabiting Salt Water." Amer. Journ. Sci., 1K71 ; Ann. Mag. Sat. Bist. (1), VII., pp. 230-210. X " Acariens et Insectes marins des C6tes du Buulonnais." ifer. Biol. Nord, France, II., 1889-90. § "Ihe Natural History of Aquatic Insects,'' London, 1895, ch. XII. and ten millions if wc may accept the opinion of .90 careful a naturalist as the late C. \ . Riley. Hundreds only as compared with millions! it nright easily be thought that maj'ine insects ai'e unworthy of the natiu'alists attention. Yet their poverty in numbers is really a sign of the value of the study; creatures so few in comparison with their class as a whole must have something exceptional about them, and their form and life-history must yield I'esulta of high interest to the patient enquirer. Insects are pre-eminently creatures of the air and the land. The power of flight possessed by most insects, the wonderful system of branching tubes found in almost all — carrying air to all parts of the body sO' that oxy- genation of the blood goes on everywhere^ — mark them out as essentially a class of air-breathing animals. It is well known that many insects pass the earlier stages of their life-history in streaiiis aJid ponds, but com- paratively few of the grubs have acquired the power of breathing the air dissolved in water. Most a iHaciYwna, Leach. Female seen from the Ventral Aspect. M', M-, first and second pairs of maxilUv; 2, 3, appendages on haunches of second and third legs; II.— X., limbs on abdominal senmeuts; O, ovipositor; B. pi-otnuled, and b, withdrawn bladder-like sacs on abdominal segments. Magnified 5 times. Fio. 2.— Mandibles (Mn.), and Maxillnla; (Mxl.) of Hansen ("paraglossae" of most authors) dissected out of the head. Magnified 20 times. Fio. 3. — A Scale from the Back. Magnified 25 times. Januaky 1, 1901.] KNOWLEDGE, 21 lives.' Similar protective colouring is to be seen in our other British species — .1/. poli/poda (Linn.) — which is often abundant in stony places in the hill-countries. For our knowledge of the habits of Jlachilis mari- timi], as of its sta'ucture, we are chiefly indebted to Oudemans. He observed the insects cai-efully on the Dutch coast, where they frequent the stones of dykes and searwalls, and the wooden piles of sluices. Fx'oni May to November they are veiy lively, a.nd often wander about singly. " It seems," he writes, " that they greatly like warmth. I have seen them on a hot August day run and leap very briskly on the hot stones of a dyke." In winter they withdi'aw into holes and chinks, where they crowd together in great numbei-s. Only full-grown individuals are to be seen in autumn and winter, but both adults and young in midsummer, whence it follows that the young are hatched in spring, and that the insects live for more than a year. "' They are," writes Oudemans, " very inquisitive. If I approached a place (except in winter time) where they were to be found they usually came to the light. Did I approach too near, they began to nin and jump about. If they fall into the water it does not matter, since they arc hardly wetted thereby. They can move over the surface-film of the water, and even make .short leaps there- on. Usually they reach the shore again after a short time, or find an object up which they can climb. I have often seen this." He goes on to describe how he kept specimens in captivity on the siirface-film of water in a glass vessel up whose smooth wall they could not make their way. " They remained there forty-eight hours. When, afterwards, I gave them a chance of regaining dry land, they took the opportunity, and were perfectly right again after a few moments." It seems, thei'cfore, that Machilis is well enough adapted to a life by tlie sea^- shore. They appear to feed on vegetable refuse, but, like many creatures higher in life's scale, they fast during winter. No one can examine Machilis without being struck by its general likeness to some other, and more familiar, creatures of the sea^shore — the s.and-hoppers and their relations belonging to the crustacean order Amphipoda, wliich have lately been so ably described in these columns by Mr. Stebbing. Everyone knows that the Crustacea fonn a class of animals distinct from the Insecta, yet both cla-sses are included in the great Race of joint«d-l egged animals or Arthropoda. Very divei'se opinions have prevailed among zoologists as to the relationship between insects and cmstaceans. It was at one time thought that the Bristle-tails, the most primitive of insects, as well as the cnistaceans, could be traced back to an ancestral form resembling the well- known zoi-a-larva of a crab.*" Of late years, however. Ies3 importance has been attached to larvae as indicative of relationships, and the view that there is but little connection between insects and crustaceans has been gaining ground.** But quite recently the problem has been attacked from a fresh point of view, and a rather close relationship between the Bristle-tails and the lower malacostracous Crustacea — the Amphipods and Isopods — has been advocated by the Swedish zoologist Hansen. ft It is well known that a typical insect, like a cock- roach or a beetle, has three pairs of jaws — a pair of r K. iraeckel. " The History of Creation." Loudon, 1876. *• F. W. Futton and others "Arc the Arthropoda a Natural Group? " yatural Science, Vol. X., 1S97, pp. 97-117. +t " A Contribution to the MorpholoiiT of the Limbs and Mouth Partsof Crustaceans and Inseets " Ann'. Afar/. Nat. IlUt. (K) XII 1893, pp. 417-434. Hee also Nat. Set. {loe. cit.), pp. 103-5. mandibles and two pairs of maxUlae, the second of which are more or less completely fused together to form a " lower lip " (labium). In Crustaceans wc also find a pair of mandibles and two pairs of maxilla;, but in the Amphipods and Isopods the next pair of limb.s, the first jaw-feet or maxillipeds, are also included in the head region, and become partially joined to form a " lower lip." Now Hansen has suggested that a pair of structures foinid in the head of the Thysanura, united basally with the tongue, especially well developed in Machilis (Fig. 2, Mxl.), and situated between the mandibles and maxilla, arc in reality a pair of jaws which con-espond with the first maxilla; of cmstaceans. If this view be correct, there are four pairs of jaws in the Bristle-tails, and the con'cspondence of these insects with the sand-hoppers, woodlice, and their relations be- comes remarkably close, especially when we remember that the number of segments behind the head is exactly the same (thirteen) in both groups. Hansen states that vestiges of these " maxillul:e " arc to be found in tlie cockroach and other insects ; the Bri.stle-tails, therefore, seem to have retained a pair of jaws which the higher members of the class have almost or altogether lost. The mandibles of the Thysanura, too (Fig. 2, Mn), have many points of likeness to those of Crustacea. Another coiTespondcnco with the sand-hoppers and woodlice is brought out by Oudemans, who states that the cyo in Machilis as in those crustaceans has a layer of hypo- dermis-cells between the corneal facets and the crystal- lino cones. As we watch MnchilU maritima disporting itself around the rock-pools, the enquiry is suggested as to the various coasts which it haunts. All around the shores of our own islands — even to the remote Orkneys and Shetlands, as well as the Irish Aran — it has been found ; as also on the rocky co^asts of Nonvay, of Holland, of France, and Spain, and even on the Canary Isles lying out in the Atlantic off the shores of North Africa. It does not seem to range to the eastern European coasts. So far as we know, Machilis is incapable of crossing a scarcha.nnel of any breadth. Its presence on these various v/cstern continental a.nd island shores tends to show, therefore, that at some former period there must have been a continuous continental coast-line along which it could migrate. This humble insect furnishes one of the many distributional facts which point to the existence in Tertiary times of continental land lying north and south along the western margin of the present European area. And its presence on the Canaries lends support to the view- — once highly popular, then discredited, now be- ginning again to find upholders — that this old western continent may have stretched away far into the Atlantic. The mere fact that our little Bristle-tail haunts these rocky coasts calls up visions of a vanished continent, and sh.jws how land and sea areas have changed in the course of the earth's history. And when we study the structure of the insect we are carried back to a past still more remote. As we see a Machilis gliding over some ancient Archaean rock, we imagine the primaeval sea in which the fragments of that rock gathered as sediment. In that same sea, maybe, lived the far-off common ancestors of the insects and crustaceans of to-day. No "record of the rocks " preserves the form of these primitive arthropods for our study; but we can guess at their nature by help of those characters which, passed on through countless generations of living creatures, still survive in our marine BrLstle-tail. 22 KNOWLEDGE. [January 1, 1901 . Conducted by Cross. Standard Sizes for Eykpieces. — On December 20th, 1890, tbe Council of the Royal Microscopical Society adopted certain internal diameters of draw-tabes as standards for eyepiece sizes : withdrawing those which had been fixed by them in the year 1882, which were two in number, viz. : '92 in. for small stands, and 1-35 in. for large. The following were the sizes decided upon : — No. 1, -9173 inch =: 23-300 m/m. „ 2,1-04 „ =26-416 „ „ .3,1-27 „ =.32-258 „ „ 4,1-41 „ =3.V814 „ A year has gone by, and it is now possible to estimate the value of these fresh gauges and to ascertain the probability of their regular and general use. We are indebted to the courtesy of manufacturers for statements of their intentions on the subject, and although several have abandoned old sizes for the new ones, or intend to do so, there yet remain some who do not seem disposed to consult the public convenience by falling into line. It will be apparent that Xo. 1 gauge is the one known as the "Continental size," and is practically the same as the smaller gauge recommended by the Royal Microscopical Society in 1882. This is almost the universal diameter for student's microscopes, and its popularity shows no likelihood of diminish- ing. The No. 2 gauge is differently placed, and it is not unanimously agreed that its inclusion in the list is either necessary or advantageous. The number of microscopes in which this is likely to be used is extremely limited. The No. 3 gauge is very suitable for stands of medium size, but No 4 is of questionable value, for the day for the large models to which this gauge would be applicable seems to have passed. All con- sidered, it would seem that both the public and the manu- facturers would have been better placed had three sizes only been fixed, and in view of present knowledge and experience, a confirmation of the sizes of 1882, with the addition of an inter- mediate gauge, say the one of about 31 m/m., which was already in regular use, would have been a verj' convenient and accept- able range. The net result will probably be, as time goes on, that gauges Nos. 1 and 3 will become tlie standards, and it is to be hoped for the sake of uniformity that No. 2 at least may be withdrawn. The fewer the number of gauges the better for everyone. The prevailing tendency is to have a large tube, and with a fitting at the eyepiece end to receive eyepieces of the No. 1 gauge ; after all, if the body be of sufficiently large diameter for photography, it does not matter greatly whether the eyepiece be large or small, for only in the oculars of rerif low power can a large field lens be used in the eyepiece. We are informed that a general meeting of German microscope manu- facturers is shortly to take place, and it is possible that some consideration may be given to the recommendations of the R. M. Society on the subject of both eyepieces and sub-stage fittings. Universal sizes are of such prime importance that it is to be hoped that the random system which has too long pre- vailed, of every maker being a law unto himself, will be unknown in the future, and as workers realise that the standard sizes are an actual fact, they will insist on their incorporation in their stands, and so induce those makers who might otherwise be disinclined to alter the diameters of their tubes voluntarily, to meet the exigencies of modern work l>y using only the universal fittings of the lloyal Microscopical Sjciety. Blood Examination. — In recent years the examination of blood for diagnosis of diseases, especially those peculiar to tropical climates, has assumed great importance, and every practical suggestion which enables it to be more thorougiily performed is welcome. We have had sent to us the description of a method devised by Dr. W. L. Braddon, of the Malay Peninsula, which is both interesting and effective. The cor- puscles are examined in a film between (1) two square cover- glasses joined together, or (2) a square cover-glass attached to a '6 in. by 1 in. slide. Slides and cover-glasses are first of all sterilized by the method recommended by Messrs. Pakes and Howard, which is as follows :— The cover-glasses are dropped, one hij line, into a 10 per cent, solution of chromic acid, contained in an enamelled iron dish, and boiled for twenty minutes. They are then tipped altogether into a shallow basin, and washed with ordinary lap-water, until all trace of the yellow colour of chromic acid has disappeared. The water is next poured off and the slips are covered with rectified spirit. After this they are washed in ab.solute alcohol, and handled with clean forceps." These cover-glasses and slides are then dealt with as follows : — Method No. 1. — Two square cover-glasses are .accurately superposed and firmly pressed together. An edging of vaseline if for temporary purposes, or cement if for permanent purposes, is laid over all the edges, except one, which is left free, and a very small portion of that edge which is opposite to the uncemented one. M^ethoil No. 2. — The cover-glass is placed on a 3 in. by 1 in. slide in such a position that one of its edges exactly coincides with that of the slide. It is then firmly pressed and vaseline or cement is used, as mentioned in Method No. 1. Method iif Vsc. — A drop of blood is touched with the free edge of the paired cover glass or slide, whereupon the blood enters between the glasses in an exceedingly thin film, the corpuscles being spread out with beautiful uniformity, and having suffered a minimum amount of change from exposure to air and none at all from handling or pressure. When the blood film has entered, the free edge may be completely closed and the examination made. Fresh blood keeps well under these circumstances The advantages of these methods will be obvious. A number of slides can be made up and stored in a suitable air-tight bottle, and are always ready for use. No special skill is required for the making of a first-class blood-film. Comment.^. — We have tested this process practically, and found that it was necessary to put the smallest possible suggestion of cement between the covers before edging tliem outside, other- wise the cement had a tendency to run in. When the blood enters beneath the cover, so attenuated is the film that the manipulator is apt to imagine that nothing is there, but, on examination under a microscope, a beautiful single laj'er of corpuscles is seen, spread out ready for examination. DissECTrxG WITH AN Erector. — The ordinary compound microscope is not used as largely as it should be for dissecting purposes, one of the special instruments designed for the work being usually considered essential. As a matter of fact, any monocular microscope having a draw-tube will serve well if an erector be used. Nearly all the modern stands are fitted with a thread of the universal size at the lower end of the draw-tube, and into this the erector should be screwed. The objective that will be found most useful in conjunction is Ijin. or 2in., and a considerable variety of magnification can be secured by varying the extension of the draw-tube, the object, of course, being seen the right way up, and the tools, knives, &c., moving in natural directions. The reason why the erector has not been recognised as so useful an adjunct as it might have been, is probably because unsuitable objectives have been used with it, but the amateur preparer will be surprised at the great ease with which he can do his work with the arrangement above mentioned. New AppaKatds. — It is proposed, instead of systematically reviewing new appai'atus from time to time, to have a heading for " Neir apparatus deseribed liji manufacturers," and opticians who wish to notify the introduction of fresh accessories, instruments, &c., will briefly state the details for insertion. It is impossible to give a definite judgment on any item from an examination of a single specimen, and the public being made aware of the source of supply of such wares, will be better able to judge of their suitability for their requirements by communicating with the vendor, who would surely be pleased to give full information on the subject. Notes and Querie.s. — Notes and suggestions will always be welcomed from readers, and any assistance we can give by replies to queries in these columns will be gladly rendered. All communications for this column should be addressed to M. I. Cross, Kno\vleiic;e Office, 326, High Holborn, W.C. Janiaby 1, 1901.] KNOWLEDGE 23 NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. Bbobsbk'3 Pbbiodical Combt. — This object is appivacliing tlio earth and iueroasing in .ippureiit brightness. It ought to become visible at the end of Janiian . ami p;irtiouhir inteivst attiuhes to this return as the comet has not been seen since 1879. The following is extracted from an epliemeris by Berbericli in Ast. Nach., 3670 : — Distnuce of Coun't Pate. R.A. Dee. iu Millions of i;ioo. U. M. u Miles. January 14 . 20 3r.o - 16 24 37 18 . 20 7-6 - 9 37 37 . 19 421 - 3 28 40 On January 18th the comet will be about 4^ N. of a Caprieorni and moving rapidly to N.W. CoMBTART PiscovBniES IN 19(X). — These were, comparatively few and unimportant. Giaeobini found a faint comet on January 31st, which remained visible for sevenil months in large instruments. Its light was, however, so feeble that many observers with small telescoiws were disjippointeil in their efforts to piek it up. On July 23rd Borrelly discovered a pretty bright comet with a tail. The object was independently swept up by Brooks a few hours later. The comet was a very interesting and fairly conspicuous one during several weeks, being visible all night in the northern sky. Parabolic elements appear to satisfy the objervations in both cases. No periodical comets have been rcdetccted during the year. The Lbomd Metkokic Showkk.— The T.eonids again failed to put in an appearance, and we have only to admit the fact that planetary perturbation has disturbed the stream to such a degree that the denser portion was enabled to escape encounter with the earth. After the nega- tive results of 1898 and 1899, we were better prepared to accept failure in 1900. but the general result of observation is, nevertheless, very disappointing. The present generation had been led to expect one of the most striking and picturesque of all natural ))honomena, and its almost complete absence is very regrettable on many grounds. Apart froin the disappointment so widely felt, the public may be induced to entertain questionable views as regards future astronomical predictions. Perhaps it would have been mtich belter had the com- putations relating to the Leonids been made several years ago, so that the public could have been fully advised as to the doubtful character of the shower's return. Tlie work was, however, left until very late, and a good many astronomers deluded themselves and others with a mistaken confidence that the event would return quite in accordance with its usual period and traditions. It is unfortunate that, ai a rule, amateurs though pretty good observers are bad computers, while professional astronoirers, though not alway~ firstelass observers, arc good mathematicians. The latter class cannot be expected to under- take an elaborate investigation without payment, and so the matter was delayed beyond reasonable limits. We may take comfort in the reflection that the Leonid showers are not finally lost to us. Planetary influences may affect the stream in a manner contrary to that which has operated since 1866, and bring back the rencontres which gave rise to the magnificent meteoric storms of 1799 and 1833. But for the present generation of meteor-watcliers the prospect >eem8 a \c\ poor one, though 1001 and 1902 may bring us a few laggard members of the denser region of the stream. There will be no moonlight at the middle of November, 190L A large number of reports have been sent in concerning recent observations, but they are uniformly of a negative character. The Leonids were most active on the morning of November 16th, when the radiant furnished two or three meteors per hour for one observer. The radiant was .-it about 150+22'. Tne most active of thi con- temporary showers was the Taurids, with a radiant at .57 f 9 . which supplied some fine slow-moving meteors, with long paths and trains of yellow sparks. These Taurids are often conspicuously present during watches for the Leonids, and the stream yields an unusual proportion of brilliant lireballs. In the presence of a notable dearth of Leonids it is satisfactory that one of these meteors, which appeared on November 13tb, at 13h. 32m., was observed by Prof. A. S. Herschel at Slough, and by the writer at Bristol. It was of the second magnitude, and descende.t from a height of 69 miles near Wallingford to 58 miles near Swindon, traversing a real path of 24 miles with a velocity of about 48 miles per second. Several other meteors have been doubly observed, and the full comparison of the various observations appears likely to add some interesting items with regard to the minor showers of the period. FIBEBALL3 OF XovEMBEB 17. — Several fireballs were observed on this night, but they were not very exactly recorded. The first appeared at about? p.m., and there was an exceedingly brilliant one at llh. 32m. Some large meteors were also recorded on December 13th, at 7h. 40m., 9h. 20m., llh. .58m., and 12h. 26m. Like October 21st, the nights of November 17th and December 13th .seem to have eilxibited some meteoric displays of rather exceptional cliaracter. THE FACE OF THE SKY FOR JANUARY. By A. Fowler, f.u.a.h. The Sun.— On the 1st the suu rises at 8.8 a.m., and sets at 4 P.M. ; on the 31st he rises at 7.43 a.m. and sets at ■i.45 P.M. On the '2nd, at i) p.m., the earth is at its least distance from the sun, the horizontal parallax being 8-95"; the sun has then its maximum apjiarent diameter of 32' 35 ''2. Few spots are to be expected. The Moon.— The moon will be full on the 5th at 0.14 A.M., will enter last quarter on the 12th at 8.38 p m., will be new on tlie 20th at 2. 30 p.m., and will enter first quarter on the 2rth at 0.52 a.m. The following are among the oocultiitions visible at Greenwich during the month: — 1 9 Disappear- ance. k So r a St. Br- a Ii 4 < 1^ o O o 1 o fi. h Jan. ,"> 1 Cancri 5-U 9.45 P.M. 129 ifi.'i 10-50 258 2S6 It 22 fi A' Caucri .^■(i i>.;W r.M. ins 145 7-31 277 317 15 111 2S J:i Tauri 5-t 8.3 P.M. ii ;«4 8-28 331 310 8 Ii 2S It Tauri (i + 8.:!'2 P.M. « 2(1 9 28 3U2 270 8 7 L'!» D.at. ■¥ nyiK h-H R.O P.M. 76 106 6-37 268 290 9 + ■i\ \' Orionis 47 2.41 A.M. 110 69 3-36 268 229 11 13 The Planets. — Mercury is not well placed for obser- vation, being m superior conjunction with the sun on the 22nd. Venus is still a morning star, gradually liecoining less favourably placed for observation. On the 1st she rises shortly before 6 .v.M., and on the :ilst about (j.40 a.m. On the 15th the apparent diameter is lO'lS', and the illuminated part of the disc is 0-002. Mars, in Leo, rises on the 1st at about 9.20 p.m., and on the 31st about 7.10 p.m. On the 15th the ajiparent diameter is 13-8", the illuminated part 0949, and the horizontal parallax 12'9". Though the approaching opposition of February 21st is an unfavourable one as regards the distance of the planet from the earth, there is some compensation in the fact that the altitude of the planet when near the meridian is much greater in our latitude than in the oppositions, when the distance of the planet is smaller. Eros is still favourably situated, and the following abridged epliemeris, for Berlin midnight, may bo useful to those wishing to observe this interesting object : — Right Ascension. Declination. II. H. s. o / " 13 52 2 21 il 0 39 43 58 25 17 2 The apparent stellar magnitude of the planet ranges from 8'5 to 9 0 during the month. Jupiter, Saturn, and Uranus are too near the Sun to be conveniently observed. Nepjtune remains in Taurus, and may be observed throughout the night. The ])ath is a short westerly one, nearly midway between ? Tauri and rj Greminorum. The Stars. — About 9 p.m. at the middle of the month, Ursa Major will be in the north-east ; Leo and Cancer towards the east ; Gemini high up, and Canis Minor lower in the south-east ; Auriga and Perseus nearly overhead ; Orion and Taurus nearly in the soutii ; Aries and Cetus towards the south-west ; Pegasus and Andromeda in the west ; and Cygnus iu the north-west. Minima of Algol occur at convenient times, on the 3rd at 11.7 P.M., the 6th at 7.5G p m., the 2Gth at 9.39 p.m., and on the 29th at 6 28 p.m. February 1 3 43 52 ■f24 52 17 0 •4 2 21 22 52 n 11 4 21 0 20 54 19 10 4 39 43 19 0 40 21 4 58 25 17 10 10 „ 26 5 17 2 -I- 15 23 38 2i KNOWLEDGE. [January 1, 1901. Cf)rss (ToTumn. By C. D. LococK, b.a. Communications for this column should be addressed to C. D. LococK, Netherfield, Camberley, and be posted by the 10th of each month. Solutions of December Problems. No. 1. (Jeff Allen.) 1. Kt to Q.5, and mates next move. [This Problem, which has been much admired, has puzzled effectually one of our most reliable solvers.] No. 2. (Major Nangle.) Key move — 1. K to B4. If 1. . . . iM,oK*h, 2. KxP. 1. ... P to K3, 2. K to KS. Correct Solutions of both problems received from Alpha, H. S. Brandreth, G. A. Forde (Capt.), F. N. Worsley-Benisou, H. Lo Jeune, W. Nangle (Major), J. Blaikie. Of No. 2 only from W. de P. Crousaz, J. Bernard Corp. H. Boyes.—l^o. 1, If 1. RxKt, B to B5, and there is no mate. In No. 2 you overlook after 2. B to B2, P x B. A. Mvrdoch. — See answer to H. Boyes. In No. 2, after 1. B to Q4, P to Ki ; 2. B X BP, K to B7 ; 3. Q to Esq is not mate. J. Bervard Corp.— li 1. B to KtOch, Black interposes the Pawn or Knight. The King cannot go to K4 as you suggest. F. N. Worshi/'Benison. — Your solutions last month were correct, but received several days too late to acknow- ledge in the last number. Tlie Solution Tourney begins with the following Problems. The conditions were given last month, but it may be as well to repeat them. The first prize is One G-uirea, ; the second. Knowledge free for twelve months : — CONniTION.S. 1. The Touruaiuent will begin ou January 1st, 1901, and will include all the direct mates in two and three moves printed in Knowledge durinf; the year 19(.)1. 2. If a Problem be incorrectly printed it will be cancelled and reprinted. 3. Key-moves only need be given. A correct key to a two-move Problem will score two points, to a three-move Problem, three points. A second solution will score one point. An incorrect claim for a second solution will lose one point. If a Problem has no solution, the fact must be stated ; it will then count as a correct key. i. In the event of a tie for either prize, tlie Chess Editor may decide it by a further ti-ial of skill under new conditions. 5. Solutions must bear postmark not later than the 10th of the month of publication. PEOBLEMS. iv W. Geary. No. 1. Black (l(i). Whitk (U). Wliite mates in two moves. No. 2. Black (5). White (-t)- White mates in three moves. CHESS INTELLIGENCE. An important tournament has recently been concluded at the Manhattan Chess Club, New York. With the exception of Messrs. Pillsbury and Barry, all the most prominent American players were competing. The final score was: — 1, S. Lipschiitz, 8 ; 2, J. W. Showalter, 7 ; 3, A. B. Hodges, 5; 4, E. Hymes, 4; 5, D. G. Baird, 3^ ; 6, P. J. Marshall. 2i. The relative positions are not surprising, with the exception of Mr. Marshall's failure, which is unaccountable after his recent successes. It is understood that he will compete with Messrs. Pillsbury and Showalter, at the forthcoming Monte Carlo tourna- ment. In the South-Eastern section of the Southern Counties' Chess Union Competition. Kent have defeated Hampshire by 7 games to 2, the other seven games being drawn. Kent are a greatly improved side, while their opponents seem to have fallen off latterly. In the North v. South correspondence match of .50 players aside, Mr. Burn, at Board No. 1, has won one game from Mr. Gunston, a draw being agreed to in the other game. At Board No. 2, Mr. Locock is a Pawn ahead in both games against Mr. Schott. A tournament is now in progress at Sii^psou's Divan, ]\lessrs Lee, Mortimer, Miiller, Teiehmann and Van Vliet being the competitors. Mr. Mortimer is also taking a prominent position in the tournament of the British Chess Club. In the City of London Tournament Mr. E. O. Jones has wod his first eight games, but apparently not against the strongest players. Messrs. T. F. Lawrence, Herbert Jacobs and Dr. Smith have also made wood scores. For Contents of the Two last Numbers of " Knowledge," see Advertisement pages. The yearly bound volumes of Knowledgk . cloth gilt, 8s. 6d,, post free. Binding Cases, Is. 6d. each ; post free. Is. 9d. Subscribers' numbers bound (including case and Index), 2s. 6d. each volume. Index of Articles and Illustrations for 1891, 1892, 1894, 1895, 1896, 1897, and 1898 can be supplied for 3d. each. All remittances should be made payable to the Publisher of " KsowLKDflK.** " Knowledge " innnal Subscription, througboot the world, 7s. 6d., post free. Communications for the Editors and Books for Review should be addressed Editors, " Kmowledoe." 326, High Holbom, London, W.C. Fkbrvajiy 1, 1901.] KNOWLEDGE. 2o Founded by RICHARD A. PROCTOR. VoL.xxrv.] LONDON: FEBEUAEY 1, 1901. [No. 184. CONTENTS. Bv By Flowering Plants, with Illustrations from British Wild-Flowers.— I. Roots and Stems. By E. Llotd Pb.veof.e, b.a Living Millstones. By R. Ltdekker. (Illustrated) Mrs. Quickly's ''Table of Green Fields. ' By tlie Rev. D. B. FOTHERINGUAM, MA. (c.\NTAB.) Notes Constellation Studies.— II. The Region of Leo. E. Waltek Macxdeb, f.r.a.s. {Illustrated) Constellation - Figures as Greek Coin • Types. Robebt Brown, Junr., r.s.A. Constellation Figures on Greek Coins. {^Plafe.) The Canals of Mars. By Miss M. A. Ohh. Letters : Gbaduai Change in oce Climate. By Alex. B. MacDowall (Illustrated) Rainbow PHKyoMENA. By Paul A. Cobbold " Is HrsiAN Lipg Possible ojt othee Planets ': " By Thomas A. Wabino and Ahihue Ed. Mitchell .. Notices of Books Books Received ... British Ornithological Notes. Conducted tiy Habby V. WlTHEBBT, F.Z.S., M.B.O.r The Progress of Seismology during the Nineteenth Century. By Cbaeles Datisox, sc.d., e.g. 9 Microscopy. Conducted by M. I. Ceoss. {Illustrated) ... Notes on Comets and Meteors. ByW.F.DBNNiNo.F.a.A.s. The Face of the Sky for February. By A. Fowlee, p.e.a.s. (Illuttra/ed) ■ ... Chess Column. Bv C. D. Locock, b.a 25 28 31 32 33 35 38 3'J 4(t 40 41 43 13 41 45 46 46 47 FLOWERING PLANTS. WITH ILLUSTRATIONS FROM BRITISH WILD-FLOWERS. By K. Llovd Praegek, n.\. I.— ROOTS AND STEMS. Wf. cannot take a country walk without being struck by the variety of the vegetation which carpets the surface of the g^und. Lowly as are nio.st, of our native plants in comparison with those which clothe the hills and valleys of tropical countries, we find notwithstanding an infinite variety in the fonns assumed by their various pai-ts, and we may note in our islands, as well as in a Brazilian forest, the crowding, the stnaggling for room, the waj' in which every nook, every coign of vantage, is occupied by growing plants. Those species which arc best adapted for the conditions afforded by any particular situation and surroundings will achieve the most success in life; will grow healthy and strong, increase at the expense of their neighbours — for there is not room for all — and will eventually produce the gi-eatest amount of seed, to scatter abroad and carry on the race. To achieve eventual success in this sti-ugglo for life, the most important point is no doubt the adequate propa- gation of the race ; but as this can only be obtained by the success of the individual, it follows that every feature, however slight, which tends to the efficacy of the individual, is a distinct aid towards the success of the race. The requirements of plants for the can-ying on of life and growth are much the same as those which we ourselves might demand — namely, a certain amount of elbow-room, and of food and drink, light and heat. But most plants being fixed to one spot, and not capable of roaming at will, the conditions of their existence are somewhat different from those of the majority of animals. Their supply of water, and of most of the inorganic and organic substances which they need for the building-up of their- bodies, must be di-awn from the soil, in which they fii-mly fasten themselves; while for their supply of air and light they must largely depend on their own exertions, that by growth they may offer a sufficient surface to the aitmosphere and to the light of day, and not allow their neighbours to unduly over- shadow them. The function of the roots is twofold. They a.nchor the plant finnly in its place, so that storm or rain may not overtui-n it or can-y it away ; and they absorb froni the soil, by means of minute hairs, the water needed in the plant's economy, and dissolved in this water the soil fiu-nishes the plant with various mineral .salts which are needed for its growth. The roots of plants offer a considerable vai-iety of form. Annual plants have generally a much-branched root-system, not far-spread- ing. Examine, for instance, the roots of the Goose-foots or Oraches that on waste ground shoot up in a single season into pyramidal masses of foliage and minute green flowers, often three feet in height, only to perish with the first frosts of winter. In plants such as these, the rapid growth needs a continually increasing amount of i-oot surface; this is acquired more easily by repeated branching than by the lengthening of a main root. Again, as the plant has not exi-sted continuously for years on this particular spot, it has not already ex- hausted the soil immediately suiTounding its root-iitock, and in a limited area it finds nutriment sufficient for a single year's growth. A third consideration is that this elaborate structure of stems and leaves does not require to be safeguarded again.st the stoi-ms of winter, for 26 KNOWLEDGE. [Febkuaby 1, 1901. by the end of autumn its period of life is fulfilled; therefore a finn anchoring can be dispensed with. By way of contrast,- consider the roots of a young tree. This plant has a long life before it, and the future must be cai'efully provided for. The roots are long and very strong and woody — much tougher often than the branches, for they axe subject to greater stress. They spread widely, and hold the plant in its place with wonderful tenacity — as we realize when we try to weed out a few Ash or Sycamore seedlings that have got into our flower-beds. In the case of biennial plants, which during the first season of their existence form a rosette of leaves on a very shortened stem, and in the following yeai- shoot up. flower, and die, the root is often much thickened, and u.sed for the storing up during the first season of the plant-food required for the great vegetative efi'ort of the second. Our lai-ger native thistles furnish good examples of such foresight on the plant's part. Gardeners have taken advantage of this tendency of some species to enlarged roots to develop the character by continued selection of the most fleshy-rooted, and to their successful efforts we owe the juic}' caiTot, the coi-jDulent tiu'nip and beet, tlie salsify and parsnip. Biennial or perennial plants which dwell on ai-id plains, or in sandy ground, have particular need of long and fleshy roots, that they may store up food and water against times of drought, and in dry weather be able to tap the deeper damper layers of soil. If we examine the plants which grow on the dunes or on the sea shore, we shall find that many of them have a long fleshy tap-root which fulfils these pui-jjoses — the Sea-spurge for instance, and the lovely Horned Poppy. Note likewise the great length and succulence of the roots of the Sea^ Holly. Aquatic plants live under peculiar conditions. Being wholly or in great part immersed in water, instead of air, the supply of water and dissolved salts is available to any part of the plant capable of absorbing them. Roots then become useful chiefly as anchors. In the quiet watei-s of ponds and ditches, even anchorage can be dispensed with, and we may find, as in the pretty Bladderwoi-ts, or the Ivy-leaved Duckweed, that roots have been altogether dispensed with ; the plant fomis a tangled mass of delicate stems among the other aquatic lierbage, or drifts freely about on the surface ujider the influence of the wind. In certain exceptional cases, roots are used for purposes quite foreign to tlieir usual functions. The Ivy, for instance, so long as it has a wa.ll or tree-trank to cling to, sends out fi-om that side of its stem which is in contact with its support innumer- able short roots, which fasten themselves so closely to the substratum that they will often drag with them scales of bark or pieces of plaster rather thaai relax their hold. These roots ai'e generally used solely for the purpose of clinging, and the plant has in addition a well de- veloped root-system in the soil below for the absorption of water; but they are true roots, and if on a damp wall we sever the stem, the upper part will continue to grow, fed by the clinging roots, which now take up the additional duty of supplying water. Roots may even take on themselves the usual woi-k of leaves, and develop chlorophyll, for the production, from the raw materials, of plant-food, in the presence of sunlight. The common Lesser Duckweed sends from the under surface of its floating fronds a bundle of little spirally twisted i-oots which hang down into the water, and help in no small measure to anchor the plant in its unstable substratum. These roots contain chlorophyll, and, being continually exposed to daylight, assist the green parts of the plant in canying on that portion of the work which is in most cases performed by the leaves. But most roots, being buried in the ground, could make no use of chlorophyll, which can only fulfil its function in the presence of sunlight, and hence roots are usually not green. In the case of the roots of most of our common leguminous plants we have, as Mr. Peai'son has explained in Knowledge for October, 1900, a true symbiosis, or association of two separate organisms for their mutual benefit. 'In many other cases we find parasitism pure and simple, the advantages being entirely coirfined to one side. The curious Toothwort, for instance, has roots which, instead of absorbing nutriment from the soil, fasten themselves to the roots of other plants, penetrate their tissues, and draw therefrom a supply of plant-food ready made. In other cases the parasitism is only pai-tial, as in the Yellow-rattle, Eartsia, and Eyebright of our pastru'es, which, in the keen straggle for mastery which goes on in these densely populated ai-eas, take a somewhat unfair advantage by augmenting the food- supply which they produce by tlieir own exertions by stealing from their neighbours by means of haustoria or suckers developed on their roots, which fasten them- selves to the roots of adjoining plants. To this subject wo shall have occasion to return when we speak of leaves and the part they pla.y in the economy of the plant. To tui-n now to stems. The stems of plants have two principal functions. They are the fraanework on which the leaves and flowers are spread out to catch the light and air, and they are the conduits through which the raw food materials are conveyed from the root to the leaves, and the manufactiu^ed plant-food disti'ibuted from the leaves to all parts of the organism. It is with the former use that we shall chiefly concern our- selves. The stems with which we are most familial' are those which rise into the air, generally branching as they go, and thus spreading the leaves and flowers over a considerable space, to allow all to receive theii- due amount of light and air; the form and structure of the stem-system depends directly on the size, nmnber and shape of the leaves and flowers which it is designed to support. But first of all the duration of the stem must be considered. To take a few instances. In forest trees, such as the Oak or Beech, the stem lengthens year by year for a long period of time, branching at frequent intervals. To support such a huge and complicated structure under all circumstances, when loaded with leaves and fruit, or in the stress of winter gales, a stem of great strength and thickness is required. In such plants, as the stem lengthens and branches, it at tho same time increases in girth yea.r by year by means of fresh layers of woody tissue deposited imderneath the constantly enlarging layer of bark ; its sti'ength to resist both compression and bending maintaining a due pixj- portion to the weight and resistance to wind offered iDy the leafy boughs overhead. A great tree-trunk is the result. The trunk has many years in which to perfect its strength, and it becomes by degrees a solid column many feet in circumference of close-grained wood. The conditions are quite different in the case of an annual stem. Here the period of vegetative energy is strictly limited. The stem cannot be begun till winter is past, and must be finished in order that expanded flowers may give place to ripe fruit before winter sets in again. Hence rapidity of consti'uction and economy of material are all-important factors in the plant's building opera- tions. Look at the stem, often four to six feet in height, of a Wild Angelica or Cow-Parsnip, and note how beau- tifullv it fulfils the requisite conditions. Each stem Februaky 1, 1001.] KNOWLEDGE. 27 siipport-s several large leaves, and a number of heavy umbels composed of hundreds of ilowers. Their weight is considerable, and as the leaves and umbels ai-e often raised above the level of the surrounding herbage, w-ind-pressure is also a serious item to bo provided for. The stems of these plants are upright hollow columns, strengthened by transverse partitions at intervals. Given a certain amount of material a hollow tube is the strongest form into which it can bo moulded to resist pressm-e and bending. The plant has adopted precisely the form in which the building materials which have during the winter been lying ready stox'cd up in the fleshy roots can be used to the greatest advantage. These heavy umbels must be kept with their flat surfaces horizontal, else the plant would lose the striking advan- tages which this complicated inflorescence offers: hence the necessity of rigidity. In many other plants with tall annual stems, the form of inflorescence is such that a temporary or permanent bending of the stem will not render the flowers less conspicuous, or otherwise interfere with their proper fertilization ; in these a rigid stem is less required, and by bending to the storm the plant will lessen the chance of accident. Compare then with the stout I'igid hollow stem of the Angelica, with its flat umbels of flowers, the thin flexible stems of the Meadow-Sweet, Purple Loosestrife, or Meadow- Rue that gi-ow with it, all of which bend to the breeze that sweeps across the fields. The stems of water- plants offer a different set of conditions. Just as their roots serve as anchors rather than as gatherers of food and water, so their stems act as cables rather than as conduits The plant is buoyed up by the surrounding water, the stem has not to support its weight. It acte as a tie rather than as a strut, and flexibility and tensile strength replace rigidity and 2>ower to resist compression. Climbing stems exhibit remarkable features which can only be brieflv mentioned here. In plants like the Br)-onies. Hop, Vetches, the stem is suppoi-ted at many points by its convolutions, which embrace the support .to which it clings, or by the leaf-tendrils which fulfil the same office. The stem is thus relieved of the task of supporting the weight of £he plant, and serves chiefly as a conduit connecting with the root, and passing up water to the parts above. In these climbers the stem is thin, for sti-ength is unnecessai-y, and it is flexible and tough, that it may easily follow the movements of the supporting plants. But it is the growing parts of such stems that exhibit such remarkable features. In these the rotating movement that characterises almost all the growing parts of plants attains a degree that is truly sui-prising ; and along with this is developed an amazing sensitiveness which caiLses the stems or tendrils to bend towards and twine round any support with which, in their incessant movements of rotation, or circuinnutation, they come in contact. Thus the climber progresses, feeling for and gi-asping eveiything that will help it in its journey to the li^ht and air. In a large number of plants the axis or stem is so compressed longitudinally, that, as we have hitherto understood the term, it might be said to be %vanting altogether. Look at the Lesser Celendino, the Dande- lion, the Daisy, and a hundred other wild-flowers. The stem is reduced to an exceedingly short root-stock, inter- vening between the roots on the one hand, and the point of emergence of the leaves and flowers on the other. Of stems that creep or lie prostrate on the ground, or burrow under the ground, there is a gi-eat variety. Prostrate stems, like those of water-plants. have not to support the leaves and flowers, and cau aff'ord like the latter to be thin and whip-liko. Such are the stems of the Ground-Ivy and the Creeping Jenny, which produce leaves, flowers and roots through- out their whole length. The Strawberiy, several of the native Cinquefoils, and other wild-flowers, exhibit two kinds of stems — short upright stems, or " crowns," which give off lateral prostrate stems or "runners" often many feet in length ; the latter produce at various points of their growth tufts of i-oots below, and loaves and flowers above, which by the withering of the inter- mediate portions of the stem become in their turn separate crowns, to give off new runners. Subtcrranerai stems may conveniently be grouped similarly into those which produce leaves and flowers throughout their length, or at intervals. In tho subterranean stem a further modification takes place as compared with tho erect stem. Most erect stems — and prostrate stems too — are coloured green with chlorophyll, that they may assist the leaves in the manufacture of plant-food. The undcrgi'ound stem has no opportunity of doing this, owing to the absence of daylight, and it is usually white, or of the dull colours that most roots alTcct. Underground stems have likewise little need of sti'ength, except the quiet but well-nigh irresistible strength of gi-owth, by which the apex of the stem forces its way through the soil. Their suj-facc, too, being buried in damp earth, is less exposed to heat and di7ness, and need not guard against excessive evajjoration : hence we find that underground stems are frequently brittle, with a very thin epidermis or skin. These stems are excellent places for the storage of food-materials, which is the more necessary in such jjlants since, the stem being below ground, the leaves and flowers have to grow up often to a considerable height above the surface to seciu-e a due amount of light and air, and perfect the fiTiit ; hence subteiTanean stems are frequently thick and flesh}' — look at those of the Butter-bur, for instance. An extreme case of the storage of food in stems is found in tubers, such as the potato. In these, a great amount of food-material is stored around a few buds, which lie dormant during the winter, and use the food- store in their rapid growth during the following season. Stems may altogether .supplant leaves, and undertake the manufacture of the whole of the food of the plant. The Gorse funiishcs a well-known example. Tho seed- ling Gorse has little trifoliate leaves like the Genistas, to which it is related, but as the young Gorse inoreiases in size these leaves disappear, and the green stem.s- carry on the work of Ic-aves, and in addition under- take the defence of tho plant against grazing animals by means of the stout thorns in whicli the branches terminate. ThLs principle is sometimes carried further, and the stem becomes flattened and leaf-like, tho better to carry on the work of assimilation. Tho Butcher's Broom supplies one of the most marked instances of this to be found among British plants. That tho leaf- like organs of thLs plant are really stem-structures is rendered evident by the fact that the minute flowers of the plant are borne on their surface. Tho Duck- weeds likewise furnish excellent examples of leaf-like stems. Just as the sensitive i-oot-tip bends downward fi-om the commencement of growth, so the stems of most plants grow towards the light. In most plants this bendingr towards the light, or heliotropi«rii, is more powerful than their apogeotropiem, or tendency to bend away from the direction of the force of gravity. This is well seen when plants grow in a cave or recess; their 28 KNOWLEDGE lFebkuaey 1, 1901. leaves and stems arrange themselves with respect to the direction of the source of light. Climbing plants are, however, but little affected by the direction of the source of light. If they were, they would frequently grow away from the structures which support, them, which would be fatal to their continued climbing. Many, on the conirary, exhibit a marked apheliotropism, or turning away from the source of lighit. The Ivy, for instance, in its growth keeps the tip of its shoot pressed against the wall or trunk to which it clings, and will follow the supporting surface into the darkest nook. And climbei-s like the Bryonies and Vetches will grow right up through the dark centre of a hedge, while the surrounding plants bend away from the hedge, seeking the light on either side. LIVING MILLSTONES. By R. Lydekker. The mill-like action of their own upper and lower molar teeth upon one another may have been quite sufficient to suggest to our prehistoric parents the idea of opposing 3 pair of corrugated stones in such a manner that by mutual rotation or revolution they should be capable of reducing to powder hard substances placed between them. Indeed the idea of millstones is such a simple and natural one that it is quite probable it may have occurred to the human mind without reference to any prototype in nature ; and, in any case, if such a natural prototype is to be sought, it is not necessary to go further in search of it than our own dental organs. Excellent, however, for their special purpose as are thes" organs (when not subject to prematvire decay), there are other types of tooth-structure to be met with in the animal kingdom which present a much closer approxi- mation to millstones, and might well have foreshadowed these instruments, had they only been accessible to the primeval savage. But since these natural millstones occur only in marine fishes, some of which inhabit distant seas, while others are met with only as fossils deeply buried in the rocks, it is evident that the idea of artificial millstones is not derived from these natural prototypes. In other words, to use an expression now fashionable in natural science, the development of artificial and natural millstones is a case of parallelism. In spite of the fact that their early ancestors were provided with a good working set of sharply pointed dental organs, birds in these degenerate days manage to get along without teeth at all. A few mammals, too, like the South American anteaters, are in the same condition ; and some people have thought that in a few moi-e generations civilised man himself will be reduced to the same toothless state. The great majority of mammals, however, possess a more or less efficient set of teeth, varying in shape, size, and number accord- ing to the need of each particular species or group. But there is one feature common to these organs in mammals of all descriptions ; and this is that they arc strictly confined to the margins of the jaws, never extending either on to the palate, or to the .space en- closed between the two branches of the lower jaw. In many reptiles, such as crocodiles and a large number of lizards, tlie same law of dental arrangement obtains. In some lizards, and still more markedly in certain extinct members of the reptile class, we find, however, a number of teeth developed on the palate, having flattened crowns, and thus tending to make the mouth act the part of one large millstone. But we must descend a stage further in the sca.le of animated nature before we come to structures which are strictly comparable with artificial millstones and crushing cylinders. And it is in the class of fishes that we meet with these organs 1. 2. 3. Fig. 1. — A Dental Plate of a Beaked Eagle-Bay {Ehinoptera). Fig. 2. — Imperfect Dental Pktes of a Paleeozoic Shark (CocliUodns). Fig. 3. — Some of the Lower Crushing Teeth of an Enamel-scaled Fish [Cceloilus). in the full perfection of this type of development. Not that they occur by any means in all the groups of that class; the fact being that at the present day living mill- stones are going out of fashion, the great ijreponderance of modern fishes having their dental armature mainly restricted to the margin of the jaws, with or without a minor development of crushing teeth on the palate or the bones of the gullet. With the exception of a com- paratively limited number of cases, showing a different type of development, to which it is not my present intention to allude, these dental millstones are confined at the present day to those hideous marine fishes com- monly known as skates and rays, and to the singular Port Jackson shark and a few allied species inhabiting the Pacific aad Malayan seas. On the other hand, the seas of the Cretaceous, Jurassic, and antecedent epochs absolutely swarmed with numerous kinds of sharks, more or less nearly related to the Port Jackson species, whose mouths were filled with pavements of teeth showing marvellous variety of structure and beauty of oi-namentation. The skates and rays, too, displayed types of dental millstones quite unlike any of those of the present day. And in addition to these, there were hosts of enamel-scaled fishes whose mouths were likewise crammed with beautiful crushing teeth, albeit of a totally different type of structure to that obtaining in either the sharks or the rays. Although well nigh extinct, these enamel-scaled fishes are still represented by the bony pike of the rivers of North America, and the bichir (remark- able for its fringed fins and the row of finlets down its back) of tropical Africa. But it is noteworthy that in neither of these survivors of an ancient group do we find the mouth furnished with an apparatus of millstones ; while, as already said, among the host of sharks that infest the warmer seas of the globe it is only in the Port Jackson species and its three kindred that we find similar structures retained ; all the other members of the group having developed cuspidate teeth adapted for seizing and tearing soft-flcshed prev, instead of for grinding up mail-clad food. Clearly, then, there has been some general cause at work which has rendered crushing teeth, so to speak, unfashionable among the fishes of the present day and the immediately antecedent epochs. And in this con- nection it is important to notice that there has been an even more strongly mai'ked tendency to the ex- tinction of the enamel-scaled fishes, and their replace- February 1, 1901.] KNOWLEDGE •Id mcut by the ordinary soft-scaled fishes so abundant in the present seas. As the majority of these old mail-clad fishes, as well as a large proportion of the ancient sharks were provided with crushing teeth, it is a fair inference that their food consisted largely of shell-lish and crusta- ceans with a certain proportion of their own mail-clad relatives. When, however, the swift^swimming soft- scaled fishes came to the fore, they would naturally offer a more tempting and nourishing diet to such sharks and other prcdaceous members of their own class as were swift enough in their movements to make them their prey. And consequently the old millstone-jawed sharks would tend to more or less completely disappear. On the other hand, the skates and rays, which are for the most part slow-moving creatures, flapping sluggishly along on the sea-bottom by means of their fan-like tins, would be quite unable to capture the modern type of swift-swimming fish. And they have thus had to con- tent themselves with the old-fashioned diet of shell- fish and crabs, in consequence of which a large propor- tion of them have retained the dental millstones which have been so steadily going out of fa.shion among their more advanced relatives. Not that these rays and skates have by .any meaus been content with the kind of molar machinei-y that did duty for their forefathers, since some of them, together with their Tertiary ances- tors, have developed what appears to be an absolutely perfect type of living mill, far superior to that which served the purpose of their predecessors. And it must always be remembered that these beautiful living mill- stones and cylinders (which are some of the most exquisite bony structures to be met with in the whole animal kingdom) excel their artificial substitutes in that they never wear out ; being renewed either by the develop- ment of new teeth on the inner or hinder aspect of the cylinder, or by vertical successors replacing the indi- vidual teeth from below or above. And now that the dental millstones of the rays have been mentioned, it will afford a convenient starting- point for a brief survey of some of the most remarkable types of structure presented by these curious organs. The teeth of rays always form a pavcracnt-like Fig. 4. — Upper leetL of BcakeU Bay {Rhynchobalia). Flu. .5. — Part of the I'ahitc of Lepidoius, m\ Eiianiel-srijUil Fi-li I'rom t]ic AVt-altlcii. structure, of which the comj^oneiit elements are arranged in straight longitudinal rows, although (Fig. 4) they may likewise show a quiucunxial mode of arrangement. The individual teeth are not replaced by vertical successors; but, being in the form of a half-cylinder, as those in front become worn down, the whole series is pushed forwards, and new teeth are developed on the hinder margin of the cylinder. The supreme development of a dental structure ;idapted for crushing in this group occurs in the family of the eagle-rays {M i//iohiitl'hr), in which the millstone (Fig. 1) of each jaw forms a iierfect semi-cylinder or plate, made up of flat-crowned prismatic teeth united at their edges, often so as to constitute a mosaic-like pavement. No piece of modern machinery can be better adapted for crushing hard sub- stances than are these beautiful ivory cylinders and plates, the crushing power of which, when worked by the strong jaws, must be enormous, and sufficient to prind the strongest shell that can be introduced between them to powder. Although in all cases pavement- like, the millstone differs considerably in the difl'ercnt species in its structure. As an illustration of the group we may take one of the millstones of the beaked eagle- rays (Rliiuoptera), shown in Fig. 1. Here the millstone is in the form of a semi-cylinder, consisting of five or more rows of teeth ; a very usual number being seven. Generally (as in the figure) the teeth of the middle row are the widest; those of the rows on either side being considerably narrower, while the two or three marginal rows on each side may be compared to the tessara; in a mosaic pavement. A further development of the same type is exemplified by the typical eagle-rays {MyUohntis), ic which the middle row of teeth in the millstone becomes still wider, while the three lateral rows on each side are reduced to the condition of hexagonal tessarse. Moreover, whereas in the species of Rhiiu)batis both millstones ai-e in the form of half-cylinders, in Myliohatis the upper one alone retains this form, the lower being a flattened plate. The culmination of this type of structure is displayed in the rays belonging to the allied genus Ai-fohnfin, in which both upper and lower millstones are flat and composed only of the middle row of teeth, which are of great width; the lateral rows having completely disappeared. The existing represen- tative of this genus is not very large (for a ray), seldom if ever measuring more than about five feet across ; but some of its extinct predecessors must have been monstrous fish, as the teeth measure five or six inches in diameter. Quite a different type of dental armature is presented by the millstones of the beaked rays {R/iinohatida;), of which a specimen from the upper jaw of a species be- longing to the genus Elnjnchohatis is shown in Fig. 4. Here the teeth take the form of closely packed diamond- shaped knobs, arranged in an alternating manner, so that although they present longitudinal rows, yet they also show oblicjue series, so as to give rise to a quincunxial pattern. Then, again, the entire millstone in each jaw is thrown into a series of undulations, so that the upper one, as in the figure, exhibits a large median boss, flanked by a pair of smaller undulations, which are received into corresponding depressions in the lower millstone. It is difficult to conceive a machine better adapted for crushing than is presented by the jaws of the beaked rays. Of a much" less powerful typo are the millstones of the ordinary rays or skates (Raiidce) of our own coasts; and among these the common thornback (Eaia clavata) presents a very remarkable condition, since the indi- vidual teeth take the form of obtuse knobs in the female, whereas in the male the centre of each of these knobs acquires a sharp recurved point. Since every thing in nature has a meaning, it would seem a fair inference that there must be some important difference between the food of the male and female thornback, but I have not come across any observations bearing ujjo'i the sybject. 30 KNOWLEDGE. [Febeuary 1, 1901. Among tlie fossils to be obtained occasionally from the workmen in large chalk-pits are teeth of the type shown in Fig. 7 ; the specimen depicted having been purchased by myself in a pit near the road between Chatham and Maidstone. As many others were offered at the same time, it doubtless foi-med part of a more or less complete millstone, which, as is too often the case, was broken up by the workmen. These teeth form convex quadrangular bosses, the marginal portion of which consists of a broad granular area, while the centre is occupied by a variable number of bold ridges, or folds, between which are often irregular knobs. It is from these ridges that the fish take the name of Ptychoclus. For a long time it was uncertain how these teeth were arranged, but careful comparison of a number of more or less incomplete series in situ has at length solved the problem. In the lower jaw the complete millstone was formed by a median row of large teeth similar to the one figured, ou each side of which were six or seven other rows composed of teeth gradually decreasing in size from the centre to the margin. In the upper jaw, on the other hand, there was a central row of small teeth, flanked on each side by a row of large ones, externally to which came a series of rows gradually diminishing in size. From this mode of arrangement it is inferred that Ptychoclus was a ray ; and the whole dental structure is as remarkable for its perfection as a crushing machine as it is for its inta-insic beauty. Even more elegant from an sesthetic point of view are the " millstones " of the Port Jackson shark {Gestracion) and its allies j the upper jaw of the Aus tralian species being shown in Fig. 6. In place of forming a continuous plate across the palate after the fashion of the eagle-rays, the individual teeth in this gi'oup are arranged in obliciue bands round the edges and inner sides of the jaws,* showing in the hinder region a melon-shaped swelling of remarkable graceful- ness, which would form an attractive ornament for the capital of a jiillar. In this melon-like portion ;■ -■^. .1 p- J Ir- '^^ '4jt %^ ^^ -. lX '/hv ^M> J^ ^ ^n. -■■.*JSBKm wtkit:M a& . -^. ^Bnuh^^^^^ ^B||g^ ti£i^^^ ^^^ ^ w Fig. 6. — Upper Dentition of the Port Jatksou Shark (Cesfracion). Fi&. 7. — A Tooth of the Ridge-toothed Ray {Ptychodus). of the millstone the individual teeth form blvmtly convex oblongs ; those of one row being markedly larger than all the rest, while the rows in front of and behind this do not correspond with one another in size. * Strictly speaking, the tooth-bearing cartilages of sharks are not true jaws. Examined with a lens, each of these blunt teeth is seen to have a minutely pitted structure, while its median longitudinal line is marked by a narrow smooth streak. New teeth are being continuously produced on the margin of the series on the inner side of the jaw, and as the outer ones become worn away, the whole series is pushed over towards the edge of the jaw. Proceeding from the larger rows of teeth towards the front of the jaw, it will be seen that as the individual teeth become gradually shorter their smooth median line gains promi- nence, till it finally develops into the sharply pointed cusp surmounting each of the front teeth. As already said, the Port Jackson shark and a few other nearly related species (all of which, by the way, feed on shell-fish and crustaceans) are the only sharks with millstones met with in our present seas. And it is fortunate that these have lived on, as otherwise w3 should never have gained a true idea of the dental armature of their extinct relatives which abounded in the seas of the Jui'assic epoch. Visitors to "Whitbv must be familiar with certain black oblong fossils of about an inch and a half iu length known to the quarrymen as '' fossil leaches." These are the hinder teeth of an extinct shark [Asteracanthus) nearly allied to the Port Jackson sjaecies, but of much larger size ; and although they are more rugose than pitted, they show the same smooth line on the summit. A beautiful specimen from Caen, in the British Museum, shows that the arrangement of these hinder teeth was almost exactly the same as in Cesfracion, which may thus be regarded as a survivor from a long past epoch of the earth's histoi-y. But there were other " millstone-mouthed ' sharks at a still eai-lier period which appear to have been allied to Cestracion, although the degree of relationship is uncertain. In these Palaeozoic sharks, as exemplified by Cochliodus, of which the imperfect millstones are shown in Fig. 2, the series of hinder teeth seem to have had an arrangement very similar to that obtaining in Cestracion, but the individual teeth of several series were more or less completely fused into a single solid plate, the ridges on which mark the original lines of division between the component series. These sharks exhibit, therefore, one among many instances where the earlier forms of a group are in some respects more sjiecia'ised than their descendants. So much space has been taken u]) by the rays and sharks that only a few lines remain for the millstones of the enamel-scaled fishes. In none of these do the teeth, which are developed on most of the bones of both the upper and lower jaws, ever form continuous plates ; and they are generally either spherical (Fig. 5) or kidney-beau-shaped (Fig. 3), and an-anged in more or less distinct longitudinal rows. Unlike those of the sharks and rays, these teeth, as in the familiar Lepidotus of the Wealden (Fig. S), are replaced by vertical successors ; and their mode of development is so pectiliar that in some cases the new tooth is placed wrong way up beneath the one it is destined to replace. In other instances, as in Ccslodus (Fig. 3), from the Folkestone Gault, successional teeth have not been ob- served, and the mode of renewal is consequently still unknown. Although within the limits of a single articl3 in Knowledge it is impossible to do more than give tli3 crudest sketch of a vast subject, yet what has been written may be sufficient to attract my readers' interest to an extremelv fascinating branch of zoological studv. February 1, 1901.1 KNOWLEDGE. 31 MRS. QUICKLVS "TABLE OF GREEN FIELDS." llV the KCV. 1). K. FoTlIElil.NL.llAM, MA. (CANTAli). O.NE of the ple ness. The constellation of tlic Lion is very easily found when the Great Bear is known. " IS'catli her liiiul foet, .as ru.sliiii<; on lii.s prey Tlio lordly Lion griH'ts tlie loril of day. " The Grcv.._. ^ t < / •-. / COMA r^"/ / *,-, •i ■ ^/ V •a • . XI X IX .St.iv Map Xo. 2 ; The Region of Leo. Zodiac. Its most significant feature is found in the centre of the group ; a pair of stars between the fourth ajid fifth magnitude. Gamma and Delta, north and south respectively of a misty looking object. These are the twin " Asses," standing right and left of their " Manger," Praesepe. " Like a little mist. Far novth in CaiieiT'.^ leri-itory it floats. Its confines are two faintlv glininicring stars ; These !ire two Asses that a Manu'er piirts." Many a young beginner has fancied that in Praesepe he has discovered a new naked eye comet, but the least optical aid shows it to be a cluster of small stai-s, and directly Galileo turned his telescope upon it, he detected its nature, counting some thirty stars within its borders. The Asses and the Manger appear to be is natural enough, and iin doubt many stories like that of Romulus and Remus took their form from such a nature myth. But the idea of strife is not the leading one in most of the legends relating to the stars Castor and Pollux, who are indeed shown as man and woman on many zodiacs, and I think that this fact renders it questionable if it is safe to press far the considerable doubt on the root idea of Mr. Brown's theory that the ancients, so to speak, solarized the stars, designing the constellations to perpetuate the stories in which they had dramatized their conceptions of solar and lunar relations. The limits of the constellation are easy to trace out. Four fairly bright stars, nearly in a straight line, mark the feet of the Twins, whilst Castor and Pollux mark FEBRr\RV 1, 1001. KNOWLEDGE. 35 tlieir heads. They are standing iu fact upon the Milky Way. The four feet stiws ai-e Mu, Nu, Gamma, aud Xi. Close by Mu is Eta, auothcr star in the foot of Castor, and in the neighbourhood of those two stais is a splendid cluster, 35 Messier, wliieh is just visible to the naked eye. but which well repays examination with the opera- glass. Castor is one of the most celebrated of double stai-s, though of coui-se altogether beyond the gi-asp of an opera-ghiis as the components ;u'e uot G" apart, but the constellation as a whole is a fine one for examination with the opera-glass, especially in the region of the Milky Way. The contrast in coloiu' between the two principal stai"s, Castor and Pollux, is noticeable enough even with the naked eye, but becomes very striking when the glass is turned upon them. Gemini forms the home of several important metcoi'-radiants, especially that of December 10 to 12. Between Leo and Ursa Major is a modern constel- lation, called Leo Minor, framed by Hevelius out of the unformed stars which he found in this region. Its components none of them exceed the fourth rank, and it is chiefly noticeable to the naked eye astronomer a.s the home of a meteor radiant of the second rank. The Lynx, lying between Ursa Major and Cancer, is __ N • ^CVCMUS • ORA • * •* CEPHEUS « • }li«CO • • * • , liiKO'^^- ewTts • • ami '•:^,'^'Jc, ' coins ""«<•, „,»" TOO CrNiS v-% llie Hiduigbt Sky for Loudon, I'Jul, ]<\bruaiy 5. an even fainter constellation than Leo Minor; its two principal stai's Alpha and 38 make a visual i>air, very similar to the three that have already been noted as marking the plantigrade feet of Ui-sa Major, aud as Prof. Young has suggested, they might well have been taken to have made up the foui-th, though, had this been so, our Bear would have been a '" high-stepper " of most un-ursine agility. Underneath the three stais which make the handle of the Plough, or tail of the Bear, is a bright stai-, easily recognized from the comparative bareness of the region in which it is placed, which is known as Cor Caroli, " Charles' Heart," so called because Sir- C. Scarborough declared that it shone with peculiar bright- ness the night before Charles the Second made his entry into London on his restoration. This name, however, attaches only to the single star; the constellation like Lvnx and Loo Minor, being one of those which we owe to the ingenuity of Hevelius, who named it Canes Venatici, the " hiuiting dogs." Cor Caroli is a beauti- ful double stai", the components of which ai-e about 20" apai'b. Below Canes Venatici, and immediately to the east of the rectangle of Leo, is a constellation which, though ancient, is by no means one of the original ones. Though it possesses no bright stars, yet on a clear night tho region will attract the attention of the sharp-sighted observer, for delicate points and films of light are crowded in it. Sei-viss writes of it: — " You will perceive a curious twinkling as if gossamer spangled with dcwdrops were entangled there. One might think the old woman of the nursery rhyme, who went to sweep the cobwebs out of tho sky, had skipped this corner, or else that its delicate beauty had preserved it even from her housewifely instincts." The story of its naming is that Berenice, the Queen and sister of Ptolemy Euei-getcs, vowed her beautiful hair to Aphrodite, should her consort return safely from an expedition on which he had set out. The consecrated tress was, however, stolen from tho temple soon after its dedication, and the consequences might have been very serious had uot the royal astronomer of Alexandria, Conon, risen to the occasion, by declaring that Aphrodite had caught the tress up to heaven, in proof whereof he pointed out the constellation to the king and queen. Probably, however, the stars iu this region had already a half-recognised position as forni;- ing a sepai'ate constellation, and the quick wit of the astronomer but confirmed a brevet rank. CONSTELLATION-FIGURES COIN-TYPES. AS GREEK By KoBEET Beown, June., f.s.a. That nearly the whole of our ancient coustellatiou-fignres are to be found as types on coins will be admitted by anyone who is familiar with the subject. But of course the question for consideration is. Do they so appear ae constellation-figures ? A numismatic Ram has no neces- sary conneotiou with the zodiacal A ries. We should require very strong- evidence to show that a flaming Altar contained a reference to any constellatioual Ara, and so on. Here, as elsewhere, evei'ything is a matter of evi- dence ; nothing must be assumed, everything is possible. The next stej^ to be noted in the enquiry is that various constellation-tigures, e.g., the Signs of tho Zodiac, have undoubtedly a[>peared, as such, on coins. The twelve Signs are to be found on coins of the Roman Enipiiv, as on coins of the Emperor Jahrmgir,'^* the Cajtriconi, as the fortunate Sign of Augustus, being specially promiiicnl. Then, turning to the earlier Greek coins, we find that all over Hellas, from Italy to Pontus, constellation-figures appear as coin-types in astonishing numbers aud with the greatest persistency. Do they, then, here appear ill some cases as constellations ? So far, this would seem to be by no means improbable. But several general theories of the origin of coin-types, exclusive of any astronomical connection, have been suggested. Thus, it is said that man put on his coins what he saw around him. He saw a lion, a lion tearing an ox, etc., and stamped representations of these ou his coinage. Yes, but he did not see a gryphon, or a Pegasus, or a naked man with a club aud liou-gkiu fighting against a many-headed snake and a crab. So wo see that this theory will not enable us to explain either constellation-figures or coin-types as a ' Tide E. AV. Jlaunder, The Zodiacal Cams of the Emperor Jahdniiir Knowledge, July 1, 1890). 3G~ KNOWLEDGE. [February 1, 1901. whole. Agaiu, it is said that mau stamped on his coins images of trade and barter, e.g., sheep, oxen, goats, the siljihinm plant, and so on. But, I fear that if we attempt any general explanation of am-ient coin-types on this principle we shall be landed in great difficulties. We cannot admit a trade in gryphons^and man-headed bulls, in serpents, scor]>ions or eagles. We shall find on early (•oins-ty]ies, as elsewhere, symbolism and imitation ; and if heaven can help us to understand them in some degree, let us not disdain its assistance. The use of constellai ion-figures as coin-types has been treated of, to some extent, by M. Svoronos and Prof. D'Arcy Thompson, and also by" myself in a recent worlc.(^' But what has been said is mamly preliminary, and the subject is still almost virgin ground. I propose to illustrate it here by a few examples ; and, before referring to these in detail, would observe that 1 follow the descrip- tions of the subjects of the coins given by the British Museum experts. I would also remind the reader that nearly the whole of the forty-eight ancient constellation- figures of the Greeks were borrowed by them from their Eastern neighbours ; and that very maiiy of these figures api^ear as constellations in the literature and art of the Euphrates Valley.*^) Turning, then, to the particular examples before us, we find*'> : — No. 1. SerakJes Jciieeling. ' Herakles bearded, naked, kneeling on one knee, r.' "With club, strung bow and two arrows : behind. Tunny. Cyzicus. Cir. B.C. 500 — 450. Every Sign of the Zodiac, except Aquarius, and other con- stellation-figures, whether as such or not, a[)pear on the coins of this city, which, through Miletus and Lampsacus, is connected with Crete and Ph. influence. We know from Panyasis of Halicarnassus (ob. cir. B.C. 457), that the constellation which Aratus ca.]ls the Kneeler (Engonasin), was called Herakhs=Fh. HareAhal ('the Traveller'). Amongst the names of this constellation are MeUcarlus (=Gk. Melckerfes, Ph. MeJqdiih. ' King-of-the-City '), Malka ( = Ph. MeleJch, 'the King'), Pahmon ( = Gk. PulaiiiioH, Ph. Baal-Uamon, 'the Burning-lord'), and Maccris (=3Likfjr=A[el(/ihth). A good instance of the type is the fine kneelmg Herakles of the Ph. Thasos ;I5) but the prototype is the Euphratean Gilgamesh (Gk. Gilgamos, Aelian, xii. 21), the 'giant-king,' who so fre- quently appears in Euphratean art bearded and kneeling on one knee, contending with a Lion, whose skin, in Hellas, he, as Herakles, wears or carries. In Tab. No. 83 — I — 18,6u8 'the constellation of the King' (Sumero- Akkadian Mul Lugal, Bab.-Assyrian Kakkah - Sarm) appears above ' the constellation of the Scorpion,' as on our own Globe. No. 2. Hcrakki^ iriiJi Hydra and Oral. 'Herakles striking with club held in r. hand at Hydra which rears up before him, and whose nearest head he trrasps with his 1. hand ; at his feet crab ; over his 1. arm, lion's skin.' Phaestus. Cir. b.c. 431-300. The storv of the fight is told by Apollodorus (II. v. 2). A great scholar once said to me that if I had tried to invent a tale to support my view, I could not have hit on anything so perfect. According to Pausauias (II. vi. 3), Phaestus was a son of Herakles - Primitice Constellations, i. l')l-2il. ' Vide Ibid, passim. ■> As the writers I quote are not uniform in their systems of spellin" proper name?, I do not pretend to uniformitv in the matter in this Taper. IJ.-spite vehement prejudices, it is inuch better in scienti6c works to write proper names in their original forms, e^., not to clotlie a Greek name in a Latin dress, or a Bahvlonian name in a Hebrew or Greek dress. I use the following abbreviations :— Bab = Babvloniau I'h. = Phoenician, Gk. = Greek. ^ Vide Svoronos, Ti/pes mon. des anciens, pi. xr. who taught the people of Sicyon to sacrifice to his sire, not as a hero but as a god (lb. x. 1). Here we note the introduction of the cult of a foreign divinity. The Hydra, Crab, Lion and King were known as constellations in the planispheres of Babylonia and Phoenicia. As I have shown elsewhere, they originally rejn'esented certain archaic and pre-coustfillational ideas. Phaestus was one of the most ancient cities of Crete ((/. II., ii. 618), and one of the three said to have been founded by Minos. Sacred symbols such as these must have been familiar long ere they were reproduced on coins. Hence, we see here on a coin an archaic legend which had already been transferred to the skies, i.e., we have constellation-figures as coin-types. The Lion, Crab and Water-snake of the modern globe preserve the story. King Herakles could not be placed next them, even in the Bab. Sphere, as he had already been located elsewhere. These obvious instances justify us in presuming a probable, or almost certain, connection between constellation-figure and coin-type where, at first sight, the evidence may not be quite so clear. Herakles is perhaps the most familiar coin-type throughout Hellas. No. 3. Herakles u:ifh Boir, Arrotv and Birds. 'Herakles naked, kneeling r. and discharging arrow ; before him two birds.' Lamia (Thessaly), b.c 3l)0 — 100. This scene is stiU better depicted on the familiar gem which shows Herakles naked, kneeling on r. knee. Lion's skin over his 1. arm, discharging arrow at three birds fronting hiiu in a row. Here we have actually a combination of five con- stellations, very much as they appear on our globe to-day, i.e^ Herakles, the Man kneeling, discharging his Arroir {Sagitta) at the three birds, the Vulture (Lyra ', the Su-an (Cygnus),a.iid the Eagle (Aqiiila). The ancient little con- stellation the Arrow affords an excellent illustration of the mistaken views which formerly prevailed about these heavenly forms. The great K. 0. Miiller tells us that there is ' nothing mythological ' about it, and that it was named from its figure.' Had he been asked. Why then, was it not callefl the Lance or the SeejAre ! he could have given no answer except that men chose to call it the Arrow, which would be merely to repeat the fact that the ancient Gre.^ks knew it as the Arrow, just as we do. As soon as we know the facts, we see why it was called the Arrow, and not the Lanre or Sceptre, and observe that it was altogether mythological. This contest of Herakles (V'ide No. 4) had its prototype in the fight between the Bab. Merodach and the three demon birds,'''' i.e., the contest between the Sun-god and the Clouds of storm and darkness. The Eagle, the Kite (^Ornis-=Cygnus) and the Laminergeier appear on the Bab. Celestial Sphere in front of the kneeling King. The simple nature-myth had already in the Euphrates Valley been transferred to the starry skies. No. 4. Herakles and Bird. Ob. ' Head of young Herakles in lion's skin. Eev. Head and neck of crested water-bird.' Stymphiilus (Arcadia), b.c. 431 — 370. Near this very ancient town ((/. II., ii. COS), the name of which is derived from the Ph. Stemhal, contracted from Mastanabal (' prob. Vlypeus Baalis,' i.e., the 'Boeotian Buckler ' of Herakles), was located the scene of the contest between Herakles-and thedemon birds v I'aus. VIII. xxii. 4). In the mythic pedigree, Stymphalus is said to have Iseen the great-grandson of Areas ('the Bright ' = the Bearuard), son of Callisto ('the Most-beautiful ') = the Crreat-hear. No. 5. Bear. ' Bear 1. walking.' Mantiueia (Arcadia). Before B.C. 471. Another coin shows the ' type 1.; counter- mark, star.' The nymjih Callisto ' made into the stars ' Vide Lajard, Ctilte de Mithra, PI. lii. 7. /Cf^CV^L £D6£. ^^ ^\ f r. 4 I \ t ti 6B < 12 .JK '^>« ^jj ■rff^ M' hr ^""h ^ i- K) JJ , . " 13 /i^'\ ;'^^>% J5 Ik'^^A 4km 6^ Vi'. ' T^} a II 0 r'0'^y « M 2> i : •• /s^ /7 CONSTELLATION FIGURES ON GREEK COINS I'JSBRDABV 1. 1901.] KNOWLEDGE. 37 .ullod tho Gnuf bear' (Pans. VIII., iii. :^ ; Viilo No. t). The iiivthic leijeiul is, of course, vastly older tliau tho i-oiuui^e. No. Ga. PeijnsHs. ' Pegasos bridled, witli curled wiiit;', walkiug 1.' Corinth, b.c. 400 — 338. The type appears ou the earliest L'oriuthiau coius, bo. (ISO. "The constella- tion of the Hoi-iie ' occurs iu the Eujihratean star-lists and in Eujdirateau art.i"> The Wiuged-horse was ' familiar to the iiuaginatious of Mesopotaniians.'"^' The creature also occurs ou a well-kuowu Hittito seal, iigured by Wright, >'"' Lajard, and others ; and appears on coins of Lycia, and on those of the various Corinthian colonies. Sometimes, as in the heavens, a Demi-horse winged is shown, e.tj., on coins of the Ph. settlement Lampsacus ('the Passage,' i.e., across the HeJlcspout). Corinth was the abode of Hippouods ('the Wise-horseman') commonly called Bellerophou ( = l'h. Baal Raphon. Berard). Pegasus is the Horse ' bridled ' (Sem. Petjoh ' Bridle '). No. 7. Peganus and Fish. ' Pegasus flying; beneath. Dolphin,' an adjacent constellation. Syracuse, b.c. 3t5. Earlier type Bemi-hurse and Fish, a Ph. coin of Panormus. A combination of Pegasus and ihe Foremost Fish in Pisces. No. y. Mam and iFish. ' Kaui kneeling 1., head turned back ; beneath Tunny.' Cyzicus. Cir. b.c. -500—4.50. It was supposed that the zodiacal Jiom, the ' pecudem Athauiantidos,'(i*" the Kam of Athamas (=Tammuz, the Semitic Sun-god), had carried Helle across the Hellespont, near the city. Aries has always been represented with reverted head. Thus, Manilius, i. 263-4: — ' 4-u™to princcps Aries in vi-Ucre fulgens Sespicif, admirans aversum surgere Taurum.' The Northern of the two zodiacal Fish 'the Chaldaeans'call Chelidouias,'(") the Tunny. There was an important tunuy-fisherj at Cyzicus, which would influence the choice of symbols. No. 10. Ram. ' Helle seated sideways on ram ilyiug r.' Alus (Thessaly). b.c. 400. Alos,. otherwise Aleus (i.e., 'Ram-town,' Heb. and Ph. Aiji/, Bab. -Assyrian Ailtii:, 'Ram'), was said to have been built by 'the hero Athamas.'ii-) Ihe Ob. bears the head of Zeus Laphystius (' the Gluttonous,' i.e., the Ph. Baal Krouos), to whom human sacrifices were offered. In the time of Pausanias (IX. x.\.\iv. 1) the spot was still showu in Bceotia where it was said Athamas was about to sacrifice Phrixos and Helle to Laphystius, when the_y escaped upon the Zeu.s- sent ram. Knsariqijo (' the Ram ') was the first of the Bab. Signs of the Zodiac. Thi.s flying Ram is i>laiuly not a specimen of the ordinary sheep, which men were supposed to ])ut ou coins because they saw them around, or bartered them. No. 11. Bull and Grapes. 'Bull standing; beneath, bunch of grapes.' Pariuni (Mysia). b.c. 400 — 30O. A colony of Miletus (Vide No. I), Paros, and Thasos, Ph. centres. The Clusterers {Pleiades) are freijuently repre- sented iu coin symbolism by a cluster of grapes (Pdrp'j;). ' They are called a grape-cluster.' (i-'l A coin of Mallos in Cilicia shows doves whose bodies are formed of bunches of grapes, ' the dove-emblem and the grape emblem of the Pleiad being here united or intermixed.' 0^) Prof. " Vide E. B. Jr-, The Heavenly iJisplay, x'ig. liv. -Perrot, Hist, of Art in CUal. ii. 171. Vide Fig. S9, 'Winged Horse.' '' Empire of the HitHtes, PI. xvi. "' Ovid, Fasti, iv. 90.3. " Schol. in Aral. Phainom, 242. '- Strabu, IX. V. 8 ; vide Xo. 'J. •i'ScAol. in //. xviii. 486. '* U'.Vrcy Thompson, Bird and Beast in A/ict. SymhoHsm, p. IS-. Thompson well points out tho couuectiuu between Oiniis, ' a kind of wild dove ' (Ile.sychios), Oitins, wine, and the Semitic ijounah, iunuh, 'dove.' Tho whole forma com- mingling of etymological connection and similarity of sound such as symbolism delight.>i in. The G rape-etusler also appears on coins of Arvad and of Juba II., in tho latter instance with a 5-rayed star, perhaps the Pleiad. So, again, on the coinage of Tauromenium (Sicily) we find ' Bull's head. Rev. : Grape-cluster.' No. 12. Bull and Ear-of-corn. ' Bull standing on car of corn.' Calcliedon. Cir. b.c. 400—350. The Ear-of- corn has been from remotest times a symbol of the goddess Ishtar ( Astartc-Aphrodite), tho original zodiacal Virijo, with her star Spiea. Both the goddess and the Bull have a primary lunar connection, and this exact combmatinu of Bull and Ear-of-corn apj)ears on Euphratean cylinders of remote antiquit_v. The scene is not a bull in a cornlield, but a bull standing on a single ear of corn iiearlv as big as himself. No. 13. Lemi-luU. ' Forepart of rushing bull.' Magnesia ad Mieandrum. Cir. b.c. 350 — 190. Another coin shows 'Humped bull butting.' We have already met with Taurus and Pleiades (No. 11), and Taurus and Spiea (No. 12). Here is the exact zodiacal Taurus, demi. gibbous, and with bent leg. The farmer would not notice denii-bulls and demi-h(>rses iu his fields. The moon-bull is, of course, at times demi ; as is the solai' Horse, when he rises and sets, especially from or into the sea. No. 14. Twins. 'Altar or shrine surmounted by tho busts of the Dioscuri, wearing pilei, their heads and shoulders appearing over the top.' Mantineia. h.c. 431- 370. We also find ' Two male figures (the Cabiri) stand- ing facing, their right hands resting ou their hips.' Syros. Third to first century b.c. Another typo is ' Pilci sur- mounted by stars,' i.e., the ' fratres Helenae, lucida sidera,'!"'' Castor and Pollux. The Euphratean name of the constellation was ' the Great Twins' I believe the Twins are sometimes represented by Harmodius and Aris- togeitoii. as on a coin of Cyzicus, a city which shows eleven Signs of the Zodiac ou its coinage (Vide No. 1). No. 15. Sniike-holder. ' The A.sklepias of Tlirasy- meJes.' Epidaurus. A reproduction of the eailier coin- type of B.C. 323-240. The famous statue of the god, with his hand ou his serpent's head, is described by Pausanias (II. xxvii. 2). Ou the Ph. coinage of Kossura a 'Cabirus' (Ph. Knhirim. 'the Great-ones 'j is depicted ' serjientein teuens.' This personage is the 'native Ph. god ' (i"' Eshinun ('the Eighth' — of the Kabirim), whose name, in' a tri- lingual Inscription of Sardinia,*"*' is rendered ' Asklcpios ' and ' Aescolapeius.' He was a great patron divinity of Epidaurus, and was there regarded as the constellational Snake-holder, ""i No. 1(3. Vc.pheiis. ' Pallas and Cei>heus, both armed, standing face to face, the goddess hands to the hero the head of Medusa ; between them, Sterope r., who holds up a vase to I'eceive it.' Tegea. After is.c. 140. Pallas, Medusa and Sterope appear in the same connection on earlier coins. Local legend : — Pallas promised Cejihcus, son of .'Vleus (Vide No. 10), that Tegea should never be captured, and gave him one of the locks of Medusa as a protection for the city.*-"' The local tradition, like so many recorded by Pausanias, is an attempt to explain facts ■; Vide K. ii. Jr., Tke Celestial Eqnn/.u,- uf Arafos. Fitr. 7, p. 11. •^ Horace, Car. I. iii. 2. ''' i)aniaskio9, Isifloicroti Bios, i-'cxUi. '"' Corp. Ins. Sem. oxiiii. ■'^ Vide Katas. vi.'; Uygi.aus, Poet Astron. ii. 14; etc. - Pa\i3. AIII. xlvii. 4. 38 KNOWLEDGE. [Febeuary 1, 1901. the real nieaninfj of which had long been forgotten. This Cepheus, who was ultimately supplied with a pedigree from Lvcaou (i.e., the votary of Zeus Ly(uios), t^^* Callisto (the G-Ve(ri-&e((r), Areas (1. ' Le dieu-soloil,' and 2. The Bearwnrd) and others, is really identical with the Ph. and coustellational Cepheus. '-"' We have here a remarkable picture of a portion of the heavens. Cepheus, who was also Baal Tsephon ('Lord-of-tlie-North'), from near tlie Pole, drops, as it were, Mtclu.'a'.'f Head {i.e., the stai' Atgol, ' the Ghoul,' evidinitly so styled from its extraordinary variations iu brilliancy) into the vase held up by Sterope ('the Bright' or ' Lightner'), one of the Pleiades, im- mediately beneath. No. 17. Vinjin and Dog. Ob. ' Head of Aphrodite of Eryx.' Eev. ' Hound looking back.' Period of transition. Town finally destroyed in the first Punic War. A very ancient seat of the Ph. cult of 'Aschtharth Erek-hayim (' Astarte lougae vitse auctor'), called Aphrodite Eryk- ine, (-3) and, in Attica, Erigone, who, according to the Athenian legend, was changed into Virgo, and her faithful little dog, 'eanis ululans Mera,' '-^* Maira ('the Sparkler '), into Procijon. Dogs were sacrificed to the Ph. goddess 'Aschtharth Melekhet (-5) Aschamaim ('Astarte, Queen of heaven ') = Aphrodite Ourauia. No. 18. Sirius. ' Forepart of dog 1. surrounded by rays ; Sirius.' Ceos. Second Century B.C. Very early coins of Cartha'a, the ancient Ph. capital of the island, bear (1) an Amphora, which from the Bab. Cylinders downwards, is a frequent symbol of Aquarius ; or (2) a Doljjhiu, the fish sacred to the Ph Poseidon; or (3) a Bunch of Grapes (Vide No. 11). Local legend : — Aristaeus prays to Zeus and Sirius against the plague. Other coins of Ceos bear a Star (Sirius) only on the Eev. The cult of astral divinities is not naturally Helenic. No. 19. Perseus. Ob. 'Helmeted head of Perseus r.' Eev. ' Gorgon's head ; beneath, harpa v.' Seriphos. Cir. b.c. 300. Perseus was especially honoured here. ('^) The scimitar or sickle with which the Bab. Merodach is armed iu his fight against the Dragon, reappears as the sickle used by the Ph. Krouos against Ouranos. This weapon, called iu Cauaanite Merch, a word which the Egyptians borrowed in the form kurp, is the harpc which the Ph. Perseus uses against the )SVa-Hu/(tiS'^c'r (Cetus), which latter constellation- figure appears on the coins of Itanos (Crete) and Agri- gentum. The whole story of Cepheus, Cassiepeia, Andromeda and Perseus is Phceniciau. (-^) Such are a few instances of Greek constellation-figures as coin-tyjies. How they got there is no legitimate cause for wonder. Their absence from the coins would have been truly remarkable. For, the great historical fact imder- lying the whole matter is simply that at an eaidy period, long before coined money, Semites skilled iu letters, navigation, astronomy, etc., invaded Hellas ; and that the Greeks, the quickest of mankind, promptly absorbed this knowledge, reproduced and bettered it. The Greeks themselves were not naturally stellar votaries. Tbeir great Aryan divinities, Zeus, Hera, Aidoueus (;=Pluto), Demeter, Hestia, Hephaistos, Apollo, Athena, Artemis, Hermes, Pan, etc., do not appear as sky-figures. It is the Phfjenician personages, Poseidon (;= the Charioteer),(-^^ -' The Ph. Liglit-god (Vide Berard, Bes Cnltes Arcadiens, p. 49 ef eeq.). -- Ph, KHpTi, the sacred 'Stone.' Cf. Cephas. -' Pans. VIII. xxiv. G. '■' Iljgiuits, Fiih. c\xx. °; Vide Jlavei-ii, Die I'hbnizier, i. tU4. ■"' I'aus. II. xviii. 1. -' Vide Grujjpe, Der phoinikische urtexl der Kassiepela-lejeiide, 1888. -- Vide K. I!. Ji', Primitive Constellations, i. 11-2. Herakles (=the .^Meeier), Eshmiia (=t\\e finake-holder). Aphrodite (=:the Virgin), Cepheus and his family, Areas (=the Bearward), etc., with sacred animals of Western Asia, e.g., the Bear, Serpent, Horse, Lion, Dog. Engle, Dolphin, etc., that we find sphered on high. And, lastly, history, archaeology, and astronomy unite in showing that a region of which Babylon was about the southern point, was the primitive home of most of the constellation-figures which we have received through the medium of Greece. Note. — The following coins are also shown on the Plate : - No. (5, Pegasus. Corinth. Cir. bc. 431—338. Eev. Head of Astarte- Aphrodite. No. 6b. Eev. Pegasus. ' Forepart of bridled horse galloping r.' Larissa (Thessaly). b.c. 480 — 450. No. 8. Ob. Pegasvs. 'With pointed wing flying r.: beneath tunny.' Cyzicus. b.c. 450 — 400. No. 14a. Twins. Eev. ' Altar surmounted by the busts of the Dioscuri 1., wearing ^nlei, their heads and shoulders appearing over the top.' Mantiueia. b.c. 431 — 370. .No. 15a. Snake-holder. Eev. 'Asklepius feeding ser- pent from patera.' Larissa, b.c. 450 — 400. The Horse on the Ob. may be Pegasus (Vide No. 6b). THE CANALS OF MARS. By Miss M. A. Oer. The physical condition of Maa-s is a problem over which discussion still rages with unabated vigour. While Mr. Lowell sees in the Martian " canals " a vast system of artificial inigation, and M. du Ligoudes geological fissures, thi-ough which rise tO' the frozen surface vivi- fying vapoui's from a still heated interior, M. Anfconiadi ascribes their doubling to a defect in focussing, and othei-s disbelieve in even their single existence. But the enigmatical lines have appeared to so many, and in the main with such consistent similarity, that the ranJjs of these unbelievers grow thin. Between rejecting the canals altogether, however, and accepting them as lactual physical entities, there are other possible alternatives. Mr. Walter Maunder, in an article in Knowledge for November, 1894, and more recently Siguor CeruUi, in recounting his obsei'vations of Mars in the opposition of 1896-7, at his private observatory of CoUurania (Teramo), showed how the mathematical lines and spots we find in the faint mai'kings of Mai's might be merely the easiest form in which, with oui- present optical means, we could be cognizant of its real feattu'es. This latter treatise elicited replies from Schiapai'elli and Flammarion, but their arguments in favour' of the physical existence of the markings as such, and of actual changes taking jilace in them, are not altogether conclusive. Siguor Cerulli's observations during the last opposition have confirmed him in the belief that the markings are optical, and his new report* is substantially a full exposition of his theory. These observations extended from August, 1898, to March, 1899, and were made with a 15J in. Cooke equatorial, with powers of 400 and 500, always without stops or coloiu-ed screens, the object being not to get .sharp defini- tion of any special feature, but as complete a picture as might be of all the phenomena. The author shows what is the explanation, on his theoi-y, of the features seen and their appai'ent variations, and brings f orwai'd ingenious and novel ai'guments +o prove his case. It must be remembered that in a bird's-eye view of a * Nuove osservazioni di Marte : Saggio di una interpretazione ottiea delle sensazioni areoscopielie. By V. Cenilli. Colhu-ania, 1900. Febbuaky 1, igOl."! KNOWLEDGE. 39 world some 40 millions of miles away all we caji take note of ai-e conti"asts in tone and colour, while the real contoiu- of objects is masked or invisible. Small or faintly-shaded objects, invisible singly, will produce an effect, if close together, of one large mass, and from our inability to see the in-egulai'ity of their grouping, will appear as round spots or long sti'caks. But con- ditions of seeing vaiy enormously on Mai-s, according to its distance and position, and tlic changing illuminar tion of its' disc ; not to speak of vai-iations in ourselves, our atmosphere and our instininients ; the contrasts, therefore, will vary, moi-e detail wiU sometimes be seen in the patches and streaks, fainter mai-kLngs at their edges will appear and disappeai-, altering thcii- outline and extent. The hazy aspect of Schiaparelli's canals may thus be a nearer approximation to reality than the shai-ply defined, and the doubling may be duo to disappearance of faint shadings between more easily grasped boundai-ies. That the canals were discovered after the opposition of 1877, being only suspected during the most favourable period, that they ai-e shai-pest with coloured screens and comparatively small apertures, while in the great Lick and Washington telescopes they have been seen either as few diffused markings, or not at all, suggest that the fine lines ai-e simply a mode under which faint mai-kings may present themselves to imper- fect vision. There is undoubtedly truth in the apparent paradox that greater distinctness comes with poorer vision, for in the best moments the eye dimly perceives, even where it cannot grasp, divisions in simple masses, curves and bluiTing in n;UTow lines, indeter- minate shadows in clear sjDaces. Whether the optical theory accounts for all the variations, including those of the polar caps, the future must decide. Most interesting is Cerulli's appeal to the past history of areography, refen-ing to Flam- marion's valuable collection of drawings, all caarefully copied from originals, in his " Planete Mars." Here we may see how in the first rude telescopes impressions of Martian markings were summed up in one large round spot, or one wide band, which latter was by Cassini and some others seen double. By degrees the easiest features of the southern hemisphere were distin- guished, but appeared so variable that an atmospheric origin was ascribed to them. It is particularly in- structive to compare Knott's drawing of November 3, 1862, with Lord Rosses of three days later. Knott's telescope was of 7^ in. apertiire, and the features which in the 6 ft. Eosse reflector appeared as large dark patches on a fainter background, he portrays as nan'ow lines on white — canals on a large scale. Again, in two excellent drawings by Kaiser, a broad band where we now recognise Praxodes, seen at the opposition of 1862. becomes, six weeks later, when seeing was more diSicuh,, two naiTow bands with faint shadings between. Other examples of gemination in lines and in spots. contractions and enlargements, etc., may be traced, and through all the series there is a remarkable, but in no wise astonishing, vai4ety of representation. One has but to consider the fugitive faintness of the objects, the imperfections of the instruments, and the personality of the observers, which affects not only their vision but their mode of portrayal. On this last point, which comes out very cleai-ly on an examination of the illus- trations in " La Planete Mars," Signer Cerulli has not perhaps laid enough .stress, nor on the influence of un- conscious imitation. Mr. Green, the artist astronomer, used to insist on the importance of the trained hand as well as the trained eye in order to obtain true pictures of planetaiy detail. Is the history of discovery with rogai-d to the large markings in Mars' southei-n hemisphere repeating itself now with the more delicate shadings in the northern? and with better optical means would they also lose their misleading appearance of mathematical regularity, and their in.stabilit.y ? The ai'tificial origin of the Mai-tian " canals " can hardly be maintained now that they have been scon to traverse the polar caps, and to appear in Venus, Merctu-y, and two of the Jovian satellites. On the optical hypothesis, on the other hand, this is precisely what we might expect. It is perhaps going too far to suggest that the bands of Jupiter and their varying appearances are strict.ly analogous to canals, since their atmospheric origin is rendered probable by other con- siderations, notably by the planet's low density ; yet there is certainly a startling resemblance between some early drawings of Mai's and i-ecent diagi-ams of Jupiter. Schiotcr's Mars, for instance, on page 77, Fig. 48, of " La Planete Mars " (1892 edition), tempts one to quote Dante: — + " Such would Jove become, if he and Mars Were birds, and cliangcd their pluina;;je." We ai-e indebted to M. Flammarion for another line of evidence. He had the happy idea of collecting naked eye views of the moon by different obsei-vers, and in response to his appeal an interesting series appeared in the " Bulletin de la Societe Astronomiquo de France," from January to Jmie of last year. The disc of the moon to the unaided eye is about the same size as that of Mai's in an average telescope, but the conditions are not quite the same, as naked ey(! vision does not admit of straining and mis-focussing to the same extent as telescopic. Nevertheless, the study of these drawings is, as M. Flammarion remarks, a lesson on the value to be attached to observations at the limit of visibility, and no one would have believed that the same thing could have been represented in so many different ways. The reader may judge for himself by personal examina- tion whether these drawings support Cerulli's theory of the canals. He will not fail to observe a tendency to draw tlie Seas of Serenity, Tranquillity, Plenty, and Nectar, as two lines more or less parallel, while the Ocean of Tempests is sometimes a narrow curved line, its eastern border only being seen, in contrast with the brilliant limb. Tyclio in one instaiice appears as a very large bright square. Whether the optical theoi-y be correct or no, probably no one will deny the wisdom of Signer Ceridli's advice to regard all Martian maps as temporary guides, sure to bo modified by further investigation. We may add, however, that to refrain altogether from speculative hypotheses would be as luiscientific as uninteresting; the sensational theories about Mars have been a stimulus to much excellent work ; but the scientist remembers that they are only theories, and is prepared to sec' them dispelled by fuller light. [The Editors do not hold themselves re.spnnsible for the opinions or statements of corre.spnndents.] GRADUAL CHANGE IN OUR CLIMATE. TO THE EDITORS OF KNOWLEDGE. Sirs. -Is our summer half (in London) getting colder f'Qual divcrebbe Giovc, s'etili e Martc Fo-ssero augelli, c cambiaaser-i p.cnnc." — Par. xxvii. 1 1, 15. 40 KNOWLEDGE. [Febbuaky 1, 1901. and drier? I would invite atteution to the following facts in this relation : — 1. The last 30 years (1871-1900) contain a smaller number of days with jnaximum temperature, 70" or more, than any other 30 consecutive years since 1841. (Of such groups there are obviously ol.) Curve A shows the general decline in those values, The first year-point re]>resents the number of those hot. days in the 30 years ending 1870, the next in the 30 years ending 1871, "and so on. The difference between the highest aud the lowest point is 2470 - 2273 = 197. Next, let us consider the number of wet months in the summer half [April to September) in 30 years ending 1870, '71, &c. We have the curve B, showing also a general decline. We may say this about it : 2. In each of the 30-ycar groups ending 1898 and '99, the number of those wet months was less tliau in any other group (than these twol of 30 consecutive years since 1841.' (The value for 1900 shows a slight rise.) The diiference between the highest and the lowest value is 89-72 = 17. I do not represent that this gradual decline is likely to continue. More proViably we shall ere long find compen- issfjd '3 %'cj 'fo^r'y '<^( yj f?^ A. Uiivs with maximum temiioniture 70" or more in 30 years ending 1870, '71, ete. B. Wet montLs in summer lialf in 30 years ending 1870, '71, cte. sation, aud a rise in the curves. It seems desirable to get light on the limits aud cause of those variations. Alex. B. MacDowall. RAINBOW PHENOMENA. TO THE EDITORS OF KNOWLEDGE. Sirs, — The double rainbow observed by Mr. S. R. S. Brown at Eastbourne, and recorded in Knowledge for December, 1900, must have been a very good example of what ai-e called " supemumerai-y " bows, and which are said to be due to interference {see Scott's " Elementary Meteorology," p. 200, 1st Edition), but I would like to see the mathematical proof of this. I have often noticed these supernumeraries,'but never more than three inside the primaa-y bow. It would be interesting to know if any one has ever observed the same thing in connection with the secondary bow. Sometimes the bow has been nearly tlie complete semi- circle, and at others and more commonly only a very small segment of the bow was projected above the horizon. One especially which I observed in Esses a good many years ago was very brilliant, and the third or inmost supernumerary only just cleared the horizon. I fancy they are always present and to be seen provided the sun's rays are br-ight enough and tlie background of cloud is dai'k enough. On the 26th September last I saw a. rainbow which besides exhibiting the supeniiuucraiy bows had another variation, which I described as follows in my weather recwd : — " The bow seen at 5.30 p.m. showed inside the ordinaiy primary, and close to it two supernumerary or interference bows ; at about half the height of the bow a short piece of the supernumeraiy bows was broken from the circular baud of the bows, and stood at an angle of 15° to 20° from the circle of the bows. The whole bow was standing against the streaky cloud rays which accompanied a shower that had just passed over, and these sti'eaks seemed to be in some degree parallel to the broken piece of the supernumeraries." As to the cause of this there must have been a re- flection of the sun's rays in some way. I should add for the further inforniation of those interested that the ground to the west rises gradually, and that the clouds on which the bow was projected were over Lake Temiscamingue, which gave me a good view of the phenomenon. Paul A. Cobbold. Haileybury, Out., Canada, December 16th, 1900. 'IS HUMAN LIFE POSSIBLE ON OTHER PLANETS?" . TO THE EDITORS OF KNOWLEDGE. Sirs, — Your correspondent A. D. Taylor enquires in the January number of Knowledge as to whether those who have made a study of the 2'lanets can throw any light on the above subject. He especially calls our atten- tion to the planet Mars, a planet which he has hithertx> considered suitable for the maintenance of human life. In passing rapidly over these controverted subjects we may say that the greater part of tlic surface of this planet is desert, that the water supply is veiy scanty,— the greenish looking patches on the planet, which have hitlierto been considered seas, are, accoixliug to Mr. Percival Lowell, nothing but large tracts of vcge^ tation gi-owing in the bottoms of the old s as. The inhabitants, if such there were, would be dependent for their water supply from the annual melting of the polar snow or hoar-frost. The atmosphere is thin, and conse- quently free from clouds ; it is doubtful whether there are any rainfalls on the planet, the m^oisture being deposited in the form of dew or hoai'-frost. The question of the composition of the Martian atmosphere is of the greatest importance. Your readers are aware that the chemical composition of any atmosiDliere is dependent on the critical temperatiu-e and the critical velocity of its gases. In other words, if the gi-avitational pull of a planet is not greater than the critical velocity of its gases, the molecules of gas will leave the planet never to retm-n. In the case of Jupiter, we find the atmosphere is exceedingly dense, while such bodies as Mercury Febriaky 1, 1901.] KNOWLEDGE. 41 and our own moon ai*e practically devoid of atmosphere. It has been Ji^isumixl that the atmosphere ;uid water (converted into water-vapour) of the moon have been, by nioleculai' motion, drawn down to the siu'face of the earth. If this be the c;Lse, therefore, we do not know what sfcises and vapours may not have been liberated from the surface of Mais. On this question, I think, the whole subject hangs. There is no reiison for doubting that, given the uecessai-y elements for the formation of living matter, tlie organic kingdoms may not have followed the same eoiu'se of evolution as our own. The organisms aio perhaps larger, owing to the lesser pull of gravity ou that planet. In conclusion, I should advise Mr. Taylor to read Peixival Lowell's admirable work on ■■ Mars, " if he desires to enter into the subject more fully. Thomas R. W.\king. Livea-pool. TO THE EDITORS OF KNOWLEDGE. Sirs, — In reply to Mr. Taylor's quei-y I should say that most scientific men would undoubtedly give a very decided "No'' to his question, and for the following two good i-casons : — First — There is not one chance in a million that any two planets among the unnumbered myriads that probably exist in space utterly unknown to us have, in the course of evolution, become so similai- in their physical conditions as to be sufficiently fitted for the inhabitants of each other to be able to continue to maintain their existence if they interchanged worlds. Secondly — Granting that the physical conditions of two planets may be sufficiently similar to enable most of the forms of life on the one to exist on the other, yet the chances against identical or even similar fonns being found on botli are immense. The almost infinite complexity of circumstances which, in the long course of evolution, has moulded living organisms on our eai'tli to what they are will have acted equally on every other planet, and effectually precluded any two forms being similar except in the remotest sense of the terai. No doubt such planets as Mai-s ai'e teeming with life, but each one with life peculiar to itself, fitted by Nature to the surrounding conditions, and no others. Looking to man, we see, as Sir Robert S. Ball remarks, that "he is a creatiu'e adapted for life under circum- stances which are very naiTowly limited. A few degi'ees of temperatm'e, more or less, a slight variation in the composition of air, the precise suitability of foohy, covering a period of about thirty-five years. The essays have appeared in reviews and other publications, and have not only been enlarged and simplified in places, but have also been given additional interest by numerous striking illustrations. There are, in the first volume essays on questions of physical geology, descriptive zoology, plant distribution, animal distribution, the theory of evolution, anthropology, and instinct : while the second volume contains contributions on educational, political, ethical, and sociological subjects. The ground covered is thus so extensive that it cannot be adequately sui vej-ed in a short review; there- fore we must content ourselves with mentioning a few of its prominent features. Dr. Wallace holds that the oceanic areas beyond the depth of 20 0 fathoms, constituting about seventy per cent, of the whole ocean floor, have been ocean throughout all known geological time. There ha-s been a large amount of controversy over this question of tl e permanency of the ocean bed, but in England a compromise seems to have been effected between the two schools of geologists. Dr. Wallace remains in possession of his 2000 fathom boundary— at least so far as Jlesozoic and subsequent ages are concerned but abandons his earlier limit of lOUi' fathoms. He accepts the Rev, O. Fisher's conclusion that the average thickness of the earth's crust on lands near the sea-level is onlj- about eighteen miles, which is all that separates ns from a layer of molten lava. It can sciircely be said, however, that the data available are suflBciently exact to justify any very definite pronouncement upon this matter. The Viilley-lakes of highly-glaciated districts are believed by Dr. Wallace to have beeu formed by ice-action. This view of Ramsay's is maintained by a group of distinguished geologists, but others — Prof. Bonney among them — explain the lakes as the result of earth movements and other causes. Wales, Scotland, Switzerland, Scandinavia, and Xorth America all present an abundance of these lakes, and all of these countries have been subjected to glacial action. On the other hand, as Mr. Oldham pointed out some time ago, there are valleys in regions showing no elfects of glaciation, very similiar to those in which lakes occur, but fiUed with the dt.%ns of rocks instead of water, and there is no evidence that they have been scooped out by glacier action. The biological es.says are most interesting to read, and several of them set forth in the clearest possible manner the theory of the origin of species by means of natural selection, Dr, Wallace shows that objections to the theory are often based upon incorrect interpretations of facts of natural history. He will have nothing to do with discontinuous variation or the inheritance of acquired characters, or any other modification - or substitute forthe Darwinian hypothesis as the methodof organic evolution. His definite conclusion, after esamining the cases put forward by naturalists who seek for a modified Darwinianism, is that •■ no case has yet been made out for the inheritance of individually acquired characters, and that variation and natural selection are fully adequate to account for those various modifications of organisms which have been supposed to be beyond their power." No space is left even to mention the other subjects dealt with in the volumes — the disguises of insects, the distribution of animals, the functions of museums, the origin of speech, the nationalisation of the land, and other matters of human interest. There are fifty-two essays in all, and each o£ them wiU prove a source of instruction to the reader. Few men have wider sympathies with Nature than Dr. Wallace, and none have a more extensive influence. •' PiBLic.wiO-VS OF THE LiCK OusEP-v.^TORY," Volume IV.. 1900. — "Meridian Circle Observations of 310 Standard Stars." By R. H. Tucker. — This is a work of great importance for pro- fessional astronomers, being the systematic and repeated obser- vation of the standard stars of the four great ephemerides of the United States, England, France, and Germany, carried out with the thoroughness aud skiU which are associated with Mr. Tucker's name. A fidl description of the instrument, of the methods of observation, and of the corrections, is given in the Introduction. " Who's '\yHo. 19ol." (Adam and Charles Black.) 5s.— We suppose it will always pass the wit of man to set- up a standard of distinction in the preparation of a work of this kind, but the continuous growth of a miscellaneous crowd of country J.P.'s, obscure M.P.'s, and still more obscure peers, will certainly necessitate some rule on the subject, or it may become a greater distinction to be out of the book than in it. Apart from this obvious danger to the utility of the work, it maj- be most heartily commended for its lucid and informing character throughout, and if it should hapjien that one wants to know anything about anyone at any time, then the information is most likely to be contained in ■' Who's Who." But there is such a dist''«ssingly large number of names of whom it may be safely said that few people will ever have any occasion to consult their record, to become interested in th<;ir orderly progress from the Universitv to the Bench, or excited concerning their recreations. Still "Who's Who ' is a greit work, grateful to the journalist, and comforting to those included in its pages. "The EN"i;r.i5iiw)M.iN's Year Book and Dieectory, 19o1." Edited by Emily Janes. (Adam and Charles Black.) 2s. 6d. net. — A truly remarkable record of the successful result of sustained effort. So far as we can see, covering the vvhole field of their activities, the book is an object lesson in the amazing advances of women during the past few years in every branch of human activity. A copy of Darwin's "The Origin of Species" can now be obtained for the sum of 2s. 6d., Messrs. Murray having, on the approaching expiration of the copyright of that work, issued a cheap edition. Ttie new book nas a cover which will not shame any library, and is well printed on thin paper. Tbat the mass of erroneous and harmful ideas which associate themselves in the popular mind with the name of Darwin will be replaced by clear perceptions of his theories is a hope" too sanguine perhaps to be fulfilled. But to possess miy mean to p»-rnse, and Messrs. Murray have at least removed the excuses of those who have light pockets. We have received from the Hon. Secretary of the Anthropo- logical Insiitute a copy of the first number of a new monthly journal entitled ■' Man," to be devoted to the record of progress made in the various branches of the study of mankind. The scope of the new periodical will include physical anthropologj-, ethnography, psychology, the study of language, and of the earlier stages of civilization, industry, and art, as well as the history of social institutions and of moral and religious ideas, so that there should be no lack of material wherewith to fill the allotted number of pages. A wise provision in the scheme is the concentration of attention on those sections of its subjects which at present suffer from lack of a journal devoted to their special interests. In addition to occasional text figm-es, each number will be illustrated with a full-page plate. That there is room for such a journal there can be little doubt, and the January issue promises well for the future. This part contains five original articles, one of which is illustrated with a coloured plate of the Japanese '■ Wheel of Life.'' These are followed by nine reviews from the pens of well-known authorities. Each article is headed by a short ■• subject-title '' in large type, and is also marked with a reference number by which it should be quoted. The annual subscription for the general public is ten shillings. The new venture has our lieartv sood wishes. February 1, 1901.] KNOWLEDGE. 13 BOOKS RECEIVED. Tie Complete Worls of John Keats. Vol. II. lulitcil by H. Buiton Foriunn. (Glasgow: Gowans & Gray.) Text-Book of Zooloifu. Part IIT.—Inrertebrafes. By Dr. Otto Sehmeil. (A. & C. Black.) Illustrated. 3s. (id. itottern Chemistrif— Theoretical, j By William Hanisiiv, D sc. (Dent.) Is. net. ilotlerit Cheiitistrji — Systematic. By William Ramsay, D.Sf. (Dent.) Is. net. Practical Enlarging. By Joliii A. Hodges, v.u r.s. (Uiffe, Sons i Sturmey.) lUustratod. Is. net. Periodic Classification and the Problem of Chemical Evolution. Bv George Rudorf, B.sc. (AVliittaker ) Illustrated, -ts. 6d. 'The Self-Educator in Latin. By W. A. Edward, M..I. (Self- Kdueator Series.) (Uodder it Stoughton.) 2s. Pd. Primer of A-itronomu. By Sir Robert Ball, Ll.D., iMi.s. (Cam- bridge Seienee Primers.) (Cambridge : rniveisity Press ) Is. (kl. net. The French Revolution. By Thomns Carlyle. (Win-il, Loek.) 2s. England's Seglect of Science. By Prof. John Puny, M.E., u.sc , y.K.s. (Fisher riiwin.) 2s. lid. net. Iinitatioii : or The Mimetic Force in 2fafure and Human Nature. By Richard Steel. (Simpkin. Marshall.) 3s. Smithsonian Institution. Annual Report of the JBoard of Regents. Smithsonian Institution. Report of the U.S. National Museum. Lunar Theorg, Lectures on the. By John Couch Adam?. M A., F.B s. (Cambridge: University Press). What is Life .' By Frederick Hovenden, F.L.S., F.G.8 . v.lt.M.s. (Chapman & Hall.) iflusti-atcd. r^». Do ire I'arg in Weight at Different Times in the Day ! By \\ . W. Wagstaffe, B.A , r.R c.s (Adlard k Sou.) In Nature's Workshop. By Grant Allen. (Newnes.) 111. 3s. (id. Edible British Fungi, An Annotated Catalogue of. By E. W. Swanton. (Huddersfield : The Museum Press.) 2s. Gd. net. Whence and Whither. By Dr. Paul Carus. (Kegan Paul.) 3s. (id. MlTIStt f ORNtTttOLOGICA Conducted by Haeey F. Witheeby, f.z.s., m.b.o.u. The Shrike's ' Lardee." — At the meetiiif; of the British Ornithologists' Club, held in December, l!)OU, a very interesting discussion rook place on the nature and use of the "larders" made by Shrikes. Mr. Hartert and the Rev. H. A. Maepherson believed that the victims Tvere generally impaled for the greater con- venience of tearing them in pieces. Mr. Howard Saunders was, however, inclined to think that it was intended as a reserve of food for the young birds. The motive for the " larder " is certainly somewhat obscure. More observation on the point is needed, and those who have opportunities for observing Shrikes would do well to carefiilly examine the ''larders" and endeavour to discover the object of the birds in forming them. These " larders " are rarely of any size, and usually consist of only one or two objects impaled, nor are these necessarily near the nest of the bird, indeed they are usually found away from the nest. It seems doubtful too if the birds have ever been observed to revisit and devour any insect, animal or bird they have impaled. — H. F. W. Tawny Owl in Ireland (Irish Naturalist, January, 1901, p. 2t).— Mr. Robert Patterson records that a Tawny Owl (Syrnium alucoj was shot on NovcmlMsr IBth, 1900, in a wood in Belvoir Park, co. Down, and sent to him in the llesh for inspection. The bird -was shot by a gamekeeper merely for the purpose of filling an empty glass ease. This is the first authentic record of the Tawny Owl in Ireland, and the only question is, was the bird an escape. On this point Mr. Patterson says that the plumage showed no trace of confinement, and that the stomach contained the remains of a full-grown rat. The bn'd was a female. Pectoral Sandpiper in Ireland. — At the Deceiid)er meeting of the British Ornithological Club, Mr. Howard Saunders exhibited, on behalf of Mr. E. Williams, of Dublin, a specimen of the Pectoral Sandpiper {Heteropugia maculaid). Tlie bird was a young one, and was shot early in October, 1900, at BelmuUct, in co. Mayo. Allhougli this American wader has often occurred in England it has only once before been recorded for Ireland. On some Migratory and other Birds olseroed in Southern Shetland in September, 1900. By AVm. Eagle Clarke, p.l.s., and T. G. Laidlaw, m.u.o.u. (Annals of Scott. Nat. Hist., January, 19(11, p)). 5 — 12). This is an interesting and valuable paper because, although the Shctlaiuls have been long and thoroughly hunted by egg colleetoi's, and the breeding birds are consequently well known, present knowledge of the migratory ino\enients of the buvls fhen^ is extremely scanty. The authors of these notes have added considerably to the little that is known by their short stay in September last. Perhaps the most valuable observations were made in connection witli the White W^agtail ( Motacilla alba). In his report on the migrations of birds to the last meeting of the British Association (see KnowI/Bdoe, January, 1901, y. 18). Mr. Clarke exjiresscd the opinion that the lloeks of Pied Wagtails, said by Saxby to arrive in Unst in the autumn, would be found to be composed of White Wagtails. This surniise proved correct, as a number of White Wagtails were observed b}' the authors of these notes on the coasts of the southern portion of tlu' main island. The umuber of other interesting observations of various species recorded in Messrs. Clarke and l^aidlaw's paper show that visits by careful observers to the Shetlands during the migration season ave sure to prove of value. Notes on the White Wagtail ('Motacilla alba. L.J in the South- east of Scotland. By William Evans, f.k.s.k. (Annals of Scott. Nat. Hist., January, 1901, pp. 12 — 15). These notes are of interest when read in conjunction with Mr. Clarke's British Association paper on the migrations of the White Wagtail. Notes on the Great Shearwater. Bv Howard Saunders (^nna/.5 nf Scott. Nat. Hist , January. 1901, pp. 15 — ISl. Mr. Saunders hero gives his authority with full particulars for his statement that the Great Shearwater on aliglitini; "strikes the water with great violence, in a manner quite different from that of a gull, and then dives." This habit of the bird had been noted by Captain J. W. Collins, who hail had "exceptional opportuniries, extending over many years, for observing the aforesaid Shearwaters upon the fishing banks " off the Eastern coa.-t of iNorth America Mr. Robert Wanvn had also noted the hibit. in som- (treat Shearwaters which he observed in Irehind in 1893. The breeding place of this bird, by the way, has yet to be discovered. Fulmar breeding at Cape Wrath. (".-innals of Scoff. Nat. Hist., January, 1901, p. 50.) .VI r. Howard Saunders records that on July 10th. 1900, when passing close under Cape Wrath, " several Fulmars came circling round the yacht, and then w'ent to the grassy plopes, on which we could see, with our glasses, birds which we had no doubt were Fulmars, sitting." Mr. Saunders adds, " The Eulmar may well be spreading, for at Soa (St. Kilda), on the 22nd of same month, there seemed to be more than ever." Nest of Young Starlings in Winter (Nature, January 10th, I'JOl, p. 252). " R. H. F." writes to Nature on January 8th, as follows : — " While a friend was walking through his fields near Broxbourue on Sunday afternoon, the (ith inst., he noticed a Starling flying towards an old elm with some food in its bill, and on going up to the tree he found a nest containing young birds. No doubt they are dead by this time, on account of the severe cold, and the dilliculty the old birds found in obtaining food for them." The Origin and Meaning of the Names of British Jiirds. By A. II. Meiklejohn (Zoologist, November, 1900, pp. 511-516). In this paper the author gives some interesting particulars of the derivation of certain popular names of birds. Many names are imitative of the birds' cries, others refer to their colours or some distinctive characteristic, but the origin of many names is obscure and un- satisfactory, while that of some, such as the gull, auk, and garganey seems to be quite unknown. All contributions to the column, either in the way of notes or plwtograph.^, should be forwarded to Harry F. Witherby, at 1, Eliot Place, Blaclclieath, Ketit. u KNOWLEDGE. [February 1, IIIOI. THE PROGRESS OF SEISMOLOGY DURING THE NINETEENTH ChNIURY. By Charles Davison, sc.d., f.g p. Seismoloc4Y ahen that on the " Seismometer," which appeared nine years later in the same work. During the interval. seismographs based on scientific principles were invented by Profs. Ewing, Gray and Milne, and their value tested by records of numerous earthquakes in Japan. A modern seismological observatory, indeed, can hardly be regarded as complete if it does not contain either the Gray-Milne or Ewing's three-component seismo- graph. While these instruments were expressly made to meet a long-felt want, we are indebted almost to accident for the use of the various forms of the horizontal pendulum which have proved so serviceable in the investigation of distant earthquakes. Hengeller in 1832, Gerard in 1851, Close and Zollner in 1869, the Darwins in 1880, and von Rebeur-Paschwitz in 1887, all designed the instrument for purposes foreign to seismology, but nevertheless prepared the way for the detailed changes inti-oduced during the last eight years by Milne, Ehlert, Grablovitz, Cancani, and Omori. Good results have also been obtained by means of the long and heavy pendulums favoured by Italian observers. (4) Changes in the amplitude, period and direction of earthquake^vibrations axe readily distinguished without instrumental aid ; but seismographs have done more than merely add precision to the evidence of t)ui' senses. They have rendered manifest features of the earthquaie-motion tliat would otherwise have passed unnoticed. Still more interesting are the revelations of the horizontal pendulum with regai'd to the pulsations of distant earthcjuakes. By the disturbance of magneto- graphs, levels, or lakes, the propagation of surface undulations to immense distances had been known for more than a century. For the fuller knowledge gained during the last twelve years, we are indebted to the late von Rebeur-Paisohwitz and those upon whom his nuuitle has fallen — Pi-of. Milne, Dr. Agamennone, Mr. Oldham and others. Much still remains to be learnt in this fascinating field of inquiry, but it is no slight feat to have proved tliat, in an eaathquake, two series of elastic waves traverse the body of the eartih with velocities of not less than 9 and 63 kilometres per second respectively ; while the slow-period undulations spread over the suHacc at the rate of 3 kilometres per second, the latter having been traced to distances of more than four-fifllis of the earth's circumference. It IS an achievement, worthy of the last years of the century. (5) 'While the more obvious earthquake-phenomena were well-known fifty yeai's ago, closer study has revealed others of equal importance. Statistical inquiries have proved that earthqualies are fai' more numerous than was formerly supposed, the most modern estimate being that one takes place on an average every half-hour. Harmonic analysis of the seismic records of different countries indicates a distinct perio^Ucity in the occiurence of eartlujuakcs, the niaxinuiiii nl' the annual period being as a rule in the local winter and that of the diurnal period at noon. The latiCst seismic maps, in which ejjicentres are mai'ked instead of disturbed areas, have led to the conclusion that the most sensitive regions are those in, which the mean surface-slope is greatest; while the Japaiie»<: earthquake of 1891 and the Indian earthquake of 1897 have shown how ra))id may be the VAie of terrestrial change. (6) Following the exjaiuple of Mallet, detailed his- tories of important earthquakes have been publisihed by various workers during the last twenty j'eai's ; par- ticularly of the Ischian, Andalusian, Charlcstown. Riviera, Zante, Laibach, Hereford and Indian eai'tli- Fkbbvary 1, 1901. KNOWLEDGE •ir. quakes. Seismological committees or departments have beeu established in several countries. Thanks to the work of Milne and Omori in Jap;ui, of SadciTa and Coronas in the Philippines, of do Rossi, Agamcnnone, Bai-attA and Mercalli in Italy, of Eginitis and Papar vasiliou in Greece, and many othei^s, some of the finest seismic regions in the world are now secure from neglect. To the laboiu-s of von Rebeur-Paschwitz, Milne, and Gerland. in founding a seismic .survey of the world, we may look forward with ronfidcnce to obtaining a rich harvest of results. (7) ConcuiTcntly with the growth in our knowledge, the origin of earthquakes has become more clearly understood. There are many shocks, marked as a rule by small disturbed areas and abnormal intensity near the centre, which we can hai'dly err in attributing to volcanic action in some cases, and in others to local disturbances partly natural and partly artificial. But all severe earthquakes, and the majority of slight ones, we seem to be equally justified in connecting with the formation of faults. In regai-ding earthquakes as the pa,ssing cffcctf; of the gradual but intermittent growth of faults, wc are relying on a source of energy competent to produce the strongest as well as the weakest shock. At the same time, we are investing earthquakes witli a significance which they certainly did not possess for us at the beginning of the nineteenth century, as indices of the site and epoch of the changes that are now taking place in the eiarth's crust. / ' Conducted by M. I.Crpss Photo-Micrography.— One of the great difficulties experi- enced by novices in photo - micrography is in the attempt to get an evenly illnminated disc with a clear sharp edge. Various devices have been tried to accomplish this, including masks placed immediately in front of the plate during exi)osure, and cuitiag down the disc by means of a mask when printing from the negative, but these are really, so far as the disc is concerned, attempts to obliterate an original error of manipula- tion. The necessity for masking off a portion of the field during printing so as to get only the portion that is in focus in the centre is not now under consideration. It is proposed to give directions which, if attended to, will ensure a clear, evenly illuminated disc with a sharp edge. In the first place suitable apparatus is requisite, and in addi- tion to the camera, microscope and objectives, the following should be included : illuminant — preferably zirconium or lime light — tjuU's-eye condenser vith irh (liaiihrucfiii immediately in front of it ; substage condenser ; projection eyepiece ; and a piece of glazed cardboard about G inches square mounted on a wooden support so that it may be central with the optic axis of the microscope ; a darkened room. The microscopic object should be placed on the stage and the objective and substage condenser adjusted exactly as for a visual examination. The microscope is then set in position on the camera base. The cardboard should now be set up at a distance of about G inches from the eyepiece. Light up, centre the jet or .source of illumination as nearly as can be roughly done to the buirs.e3'e, then centre the buU's-eye to the microscope. This is done in the following manner : — It will be observed that a faintlj* illuminated di.sc will appear upon the cardboard when light is passed through the condensers. The iris diaphragm attached to the buU's-oye must now Ije treated as the source of light, and the ])osition of the bull's-eye altered until the centre of this iris diaphragm corresponds with the centre of the micro.scope. In order to do this exactly, the iris of the bull's-eye should bo almost closed, and if the focus of the substage condenser be altered slightly the outline of this iris diaphragm will appear sliarply upon the card. It sliould, after accurate centering, be opened to just such an extent as the circumstances allow. Next alter the adjusting collar carrying the eye-lens of the jirojection eyepiece so that a sharply defined edge is given to the disc. It will now be necessary to centre the light to the bull's-eye, which together with its backward oi- forward position can be checked by allowing its image to fall upon a screen of card set at the back of the substage condenser, in the manner recom- mended in the various text-books. If all these adjustments are made with care, and the iris of the bull's-eye opened to tin: proper extent, an evenly illuminated disc should result, and nothing remains but to view and finally focus the image upon the focussing screen and take the photograph, using of course such coloured glasses, etc., as the objects may necessitate. A New He.\tini; Staue. — Mr. Leonard I'. Wilson, r.r.s., sends us the following description of a new heating stage of his own design. During the course of some recent crystallognipliic investigations, it was considered necessary to examine, micro- scopically, a number of substances at known constant tem- peiutiiros. In order to do this, a heating stage was essential, but none of tliose in geneial use appeared to fulfil the require- ments, the fault lying chiefly in the tact that the slide, being heated only from below, was cooled irregularly by currents of air. A stiige was therefore designed in which the temperature of the slide could be accurately known, and could be easily con- trolled. The construction of this stage was such that the heating medium, generally water, flowed both above and below the slide, thus heating it uniformly, while air currents could only enter by the narrow aperture through which the slide and its carrier were introduced into the stage, the circular apertures Fig. 2. in the optic axis of the microscope being protected as hereafter described. As shown in Fig. 1, the stage is in the form of a double box, forming a water jacket to the .slide audits carrier. Water of the required temperature is passed in at A, and flows out at B, the temperature being taken by means of a thermometer inserted into the tube C, round which the water passes in the middle of its course. The heating stage is fastened to the mechanical stage by means of the screw D. When using a high power, the objective passes into the upper a])erture of the stage, and is below the level of its upper surface, and in order that the stage may move freely in all directions in conjunction with the movements of the mechanical stage, it is necessary tliat this tubular aperture be greater in diameter than the objective. To prevent the intrusion of cold air which might take place owing to this difference in diameter, a vulcanite plate, having an aperture which the objective just fits, slides on the suifaoe of the stage, under the clips L,E. In a manner similar to the objective, the condenser pas.ses up into the lower portion of the stage ; space for the vulcanite plate in this case licing made by the introduction of two bars X, X, across the lower surface of the statue, which is thereby raised above the mechanical stage. The slide carrier, as shown in Fig. 2, consi.sts of a brass plate, having a circular aperture through it, 46 KNOWLEDGE [February 1, 1901. aud bavins,' fixed to it two springs, S, S. By means of these springs tlie slide is held in position on the carrier, and the carrier is also held in position between the upper and lower platts of the stage. The ^li<^e can be roughly adjusted by means of the carrier, fine adjustment being made with the mechanical stage. The heating apparatus is as in Fig. 3, and by slightly raising or lowering the flame, the temperature can be regulated and kept constant within half a degi'ee Centigrade. Light Frr.XERS. — A few years ago it was pointed out by Mr. Nelson that the use of suitable light filters improved the working of objectives in a marvellous manner, that if the filter employed was practically of the same colour as the ray for which the spherical aberration of the objective was best corrected, a good modern achromatic lens would perform equally as well as an expensive apoehromat. The most practical and successful of light filters at present in use consists of a saturated solution of acetate of copper. This should be placed in a trough and intervene between the illuminant and the substage condenser. The internal thickness of this trough should not be less than i inch ; -^-,j inch barely causes the absorption of the red in the spectrum, | inch exactly does it with an oil lamp having a i inch wick. If a more brilliant illuminant be used, a greater depth of trough can without disadvantage be employed. We recommend a trial of this medium to all workers who would improve the definition of their object glasses. Another advantage of a light filter of this description is that the full cone of the substage condenser can be used without the brilliance of illumination being so great as to cause the observer discomfort. Notes and Queries. — Com>nmi/ra*ions and enquiries im Microsnopical matters are cordially inrited, and fthoidd he addressed to M. I. CROSS, Knowledge Office, 3'2(j, Ilir/h Ilolhoni, W.C. ♦ NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. CoMETAET DiSCOTEEIES DURINft THB NINETEENTH CeNTTJET. — The extraordinary progress effected in all departments of astronomy during the past century is well exemplified in that branch relating to conaefcs, for there were nearly four times as luany new comets found between 1801 and 1000 as lietween 1701 and 1800, the relative numbers being 235 aud 62. The century just concluded lias, in fact, furnished us with many important items respecting these my.steriou3 bodies. In 1800 only one periodical comet was known, viz., that of Halley's. At the present time we arc acquainted with a large number, which are gi'ouped into families, the most numerous and best known being those with aphelia, just outside the orbit of Jupiter. During the century just opened the field of cometary discovery will no doubt continue a very productive one, but it is not likely that the figures will show a great increase as compared with the last century. The rate of these discoveries has not exhibited any marked rise since rlie year 1810, and it is difficult to see how it can bo much accelerated imless a more expeditious means of seekingfor these bodies is adopted, or many more observers than hitherto apply themselves to the work. CoiiET 1894 IV. (De Vico— E. Swift).— It is expected that this comet will arrive at perihelion on February 13th, but it will then be overpowered by the rays of the sun. Beoesbn's Comet. — This comet is moving rapidly to N.W., and ought to be well visible iu February. No annouucement of its re-discovery has, however, yet been made. In view of the fact that the comet has eluded detection at several previous returns its existence is a little questionable, aud there appears some ground lor the inference that it has, like the comet of Biela, suffered disintegration. It will, however, be diligently sought for by means of some of the large telescopes available for this kiud of work, and we may shortly expect to liear of its re-detection if it revolves iu the same orbit as formerly, and still visibly exists under the form of a comet. New Cojibt. — Anew comet is announced as having been discovered by M. Giaeobini, at Nice, on December 20th. Its apin-oximate position was R. A. 338°. Dec S. 22°. On December 2-lth, 8h. 43m., G-.M.T., its place was R. A. 344i», Dec. S. 22|°, so the object is moving about li'' per day to the E.S E. During the last iew years M. Giacobini's discoveries of comets have been rather numerous and important, and in recognition of his successful labours iu this field the French Academy of Sciences has recently awarded him the Lalande Prize. Autu.mn Meteors. — In October and November Prof. A. S. Hei-schel, of Slough, observed 120 meteors, and determined the positions of the chief radiants as follows :- 57° + 9° (11 meti-ors', 57° + 18° (11), 50° -H 28° ,8), 70° -t- 35"^ 8). 80° + 18° (6i, 75° + 13- (4), 44° + 24° (9), 44''-i- 1-^° (10, The firat two radiants represent well-defined sliowers of Taurids. The Geminids. — On Decembpr 13th the sky was beautifully clear, and a number of meteors were observed at various places. At Slough Prof. Herschel watched from llfh. to 13Jh- and recorded about 20 meteors, including tno fine ones, as follows : — llh. 58ra. — Magnitude twice as bright as Venus. Path of about 35 degrees from ^ Persei to halfway between j3 and y Arictis. Probable radiant 167° + 5°. lih. 2Gm. — Magnitude equal to Jupiter. Path from 1° N. of X Orionis to 1° S. of 7 Tauri. Moved over 30'' in f second. Probable radiant 121° - 1°. About one-third of the meteors seen were Geminids with the usual short tracks and quick motions. Mr. T. H. Astbury, of Wallingford, watched the sky on December 13th between 8h 10m and Oh. o'clock, and registered 14 meteors, of which 12 were Geminids, the centres of radiation being 109° -I- 35° and 113° -I- 32°. A later observation from 9h. 50m. to lOh. 30m. furnished three additional Geminids, but the shower appeared to have greatly declined as compared with its unusual activity earlier in the evening. Mr. C. L. Brook, at Meltham, near Huddersfield, observing for 2^ hours on December 11th, between 9b. and l2li , saw 19 meteors, of which 11 were Geminids. On December 12th he watched 3h. 25ni. of the interval between 8h. and 12jh., and saw 25 meteors, including 17 Geminids. Between lOh. 51ui. and llh. 35m. no less than 13 Geminids were recorded. On December 13th, lOh. 18|m., a rather fine J Geminid, brighter than a first magnitude star, was observed by Mr. A. King, of Leicester, and Mr. T. H. Astbury at Wallingford. The meteor fell from a height of 59 to 44 miles, and its course lay from nearly over Hertford to Luton. Length of path 24 miles, and earth point 8 miles west of Banbury. FiEEBALis. — Several of these striking objects have been recently observed from various parts of the country. The dates aud times were as under: — November 27th, llh. 10m. ; December 1st, 4h. 12m. and 12h. ; December 10th, 3h. 55m. a.m. ; December 16th, 7h. 35m. a.m. ; December 17th, 5h. 55m. p.m. Mr. G. Herbert Price, of Brixton Hill, S.W., also reports a bright meteor seen on December 13t.h, 9h. 20m , traversing a path from Gemini to the region of Aries. A rather sensational incirleut occurred on Saturday night, December 22nd, according to the Pall Mall Gazette, which states that "a large meteorite fell at'Great Parndor, Essex. Frederick Armour, a local postman, who was passing the field in wdiich it fell, states that he was blinded and stunned by the brilliant fiash of light. He was found unconscious iu the roadway." Fireball in Sunshine. — On January 6th, 1901, at Oh. 52m. p.m., a large meteor was observed from various places in Scotland and the extreme N. of England As seen from Glasgow the object is described as a large ball of fire with a long streaming tail. The meteor disappeared in the N.W. quarter at rather a low altitude, and it was directed from the E.N.E., so tliat the probable radiant was in the region of Perseus or Aries. Mr. W. H. S. Monck has kindly sent me several newspaper accounts of the fireball, but they are wanting in some of the definite particulars necessary for the computa- tion of the real path. There was a brilliant meteor seen in sunshine ou January yth, 1900 (see Kxowledoe. February, 1900, p. 47), but this object must have emanated from a different stream to that which furnished the more recent meteor. It is astonishing how many large meteors have been observed even in the presence of the sun, and it proves that they are unusually prevalent in the day-time. Unfor- tunately, however, they are seldom well observed as regards their position and direction of fiight. THE FACE OF THE SKY FOR FEBRUARY. By A. Fowler, f.r.a.s. The Sun.— On the 1st the sun rises at 7.42 a.m., and sets at 4.46 p.m. ; on the 28th he rises at 6.51 a.m. and sets at 5.35 p.m. Few sunspots are to be expected. The Zodiacal Light may be looked for in tlie west after sunset. The Moon. — The moon will be full on the 3rd at 3.30 P.M., will enter last quarter on the 11th at 6.12 p.m., will be new on the 19th at 2.45 a.m., and will enter first quarter on the 25th at 6.38 p.m. The following February 1. 1901.] KNOWLEDGE. 47 ai-e among the more intoresting occultations wliich occur at convenient tunes during tlic montli ; — ri . F1 a g E cj 1 i a li s r 3 a 1^ ij3 .So < "a § s o o o o d. Ii. F.;b I D.M. + ir--KV% S-fi 6.42 P.M. lt« IS6 71S 2.^1 2(9 12 4 „ 21 51 I'iscium .vr lv I. . . . KtPxE.] CoERECT Solutions of both problems received from J. Baddelev, H. Le Jeune, B. Harlev, G. Groom, F. J. Lea, G. A. Forde (Capt.), S. G. Luckcock, W. de P. Crousaz, W. H. S, M., J. T. Blakemore. N K. Dutt, Endcrby, F. Dennis, C. L. Massey, Eugene Henry, A. J. Head, G. W , J. Sowden, G. W. Middleton, T. H. Billiugtou, V. Johnston, H. Boves, A.C. Challenger, E. Hunt, Vivien H. Macmeikan, W. E.'P., A. Dod, \V. Jav. A. E. Wiutehouse, W. Geary, W. Bovd. C. F. P.. S. W! Billings. N. B., W. B. AUdrit't, W. F.' P., T. Earl. J. E. Broadbent, C. Child, C. S. Hudson. Of No. 1 only from J. M. K., J. A. Nicholson, W. Nash, C. C. Pennington, J. Bernard Corp. Of No. 2 onlv from A. H. Machell Co.k, L. J. R. Cripps. J. T. Stockwell, H. L. Gillespie, H. S. Brandreth, .]. W. Meyjes, Aljjha, W. Smith, F. Stokoe, J. Neville. P. A. Cohbold. — Solution of No. 2 (December) correct. No. 1, however, cannot be solved by 1. B to R4, on account of 1. ... B to Q7 (!). when 2. R to Q4 is not mate. So also, if 1. B X KP, B to B-'S. Both are good " tri.^s " Of course it would be im]iossililc for you to ])0.st in time from Canada. G. A. Fonle. — Thanks for your suggestion. I think, however, that to start numbering t lie problems continuously from the present time would convey a false impression of the antiquity of this ]iage. In the case of a monthly magazine, there is no diflioidty in referring to any problem, e.g., as '■ No. 2 of June, 1897," or " No, 1 of May, 192(;," etc. A. W. Tyer, J. M. K, and others.— I. Q to QB3 is answered by P to Kt6; and, if then 2. Kt to KG, K ta Q4. F. Dennis. — Besides giving point to the problem, the KB is necessary in Mr Allen's December problem. At any rate the composer had to stop any iininedi.ite check at K7 with the Rook, and if he uses a Black Pawu for that purpose, it must be pinned by a Bi-shop in view of 48 KNOWLEDGE. [Febri-ary 1, 1001. K X Kt. No doubt the problem could have been con- structed without it. /. Jlf. K. — I should sav that there would be no objection to it. H. L. Gillespie.— Ji 1. B x P, BxE, or KP x P are valid defences. J W. Mei/jes.—U 1. KtxP, PxE; or if 1. Kt to U3 the same ajiplies. I regret that you should score - 1 according to the rules. O. W. — Certainly ; postcards are preferred. Alpha.— 1 agree that "key only" is a very liberal condition in the case of three-movers It saves, however, a good deal of trouble, from clerical errors and otherwise, and gives comparative novices a better chance of keeping up with expert solvers. In the end it would be safe to say that a solver not caj/able of seeing the correct second moves Would have little chance of winning a solution tournament extending over a year. W. IT. Giiinh-]!. — Thanks for the prolileni, which a]ipears below. J. Sou'ileii. — Yes ; postcards are jjreferred. G. W. Middletoii. — No j)oints are given for proving a j>osition to be impossible in actual play. C. C. PuniiiiuifoH and J.Bi-niard Corp. — If 1. K to KO, Kt to B3. - /. W. Hobhs.—l. K to B6 will not solve No. 2. F. Stohoe. — 1. Kt to E3 is answered by P x R. It is strange that so many solvers have overlooked this defence. W. E. P. — A second solution is the sai;^ie as a cook ; but not more than three points can be scored for a two- mover, or more than four points for a three-mover, even if a problem has a dozen keys. /. Neville. — Many thanks, but I fear there is no space for any matter concerning a single county only. C. F. P. — It is necessary to provide for the event of a problem having no solution. The best composers occasion- ally overlook some obscure defence. To avoid the waste of time which you deprecate, no three-move jJroblem known to have no solution will be 2>rinted. C. S. Hudson. — Much regret the unfortunate lateness, Vint fear that the rule leaves no option. PROBLEMS. No. 1. By W. H. Gundry. Black (7). ^ ^ ^ W ■ a ■ i= WW wm - ^ No. 2. By B. Gr. Laws. Black (8). ^i 5 ^ S ■ m w w w%^ White (7) White mates in three moves. White (10). White mates in two moves. Owing to the large number of solvers this month — fifty- eight sent in solutions — it has been decided to give, as equal third and fourth prizes, Knowledge for six months. It is hojied that those who have temporarily lost a point or tV(o will not immediately withdraw Irom the contest. Some of the problems due to appear will give them excel- lent chances of recovery, being of a nature to deceive probably a good many of those who now head the score. CHESS INTELLIGENCE. There were only four entries this year for the Craigside Challenge Cup Competition. Mr. A. Burn proved the winner with a score of 3 wins, 3 draws, and no losses, one point of Mr. H. E. Atkins who scored 3^, losing both games to Mr. Burn. Mr. W. H. Gunston was third with 2^, and Mr. G. E. H. Beilingham fourth and last with 1. In the other jirincipal tournament Mr. A. Dod was first, and Mr. C. H Sherrard second. Mr. Billington, one of our solvers this mouth, won the second-class event. Mr. Dod, we are glad to see, has also entered for the present compe- tition. It is almost safe to predict that anyone who gets ahead of these two will come very near winning. The entries for the International Tournament at Monte Carlo include, so far as is known at present, the names of Messrs. Blackburne, Cohn, Lipschiitz, Mason, Marco, Mioses, Schlechter, Tchigorin and Winawer, a strong, thc)ugh not quite a representative list in the absence of Lasker, Maroczy, Janowski, Pillsbury and Burn. The very short tournament at Simpson's Divan was won bv R. Teichmann ; the remaining competitors, Messrs. JNIiiller, Lee, Van Yliet, and Mortimer, coming out in the order mentioned. For Contents of the Two last Nnmbers of " Knowledge," see Advertiseinent pages. Tlie yearly tound volnmes of Knowledge, cloth gilt, 8s. 6d., peat free. Binding Cases, Is. 6d. each ; post free, Is. 9d. Sub-scribers* numbers bound (including case and Index), 2s. 6d. each volnme. Index of Articles and Dlnstrations for 1891, 1893, 1894, 1895, 1896, 1897, 1898, ls!f9, and 1900 can be supplied for 3d. each. All remittances should be made payable to the Publisher of " Knowledge. " "Knovledge" innual SabsoFiption, thronghont the world, 7s. 6d., post free. Comuiiniications for the Editors and Books for Renew slionld be addressed Editors, " Knowledge," 32'5. High Holborn, I.ondnu, W.C. M.\Kcn 1, 1901.] KNOWLEDGE 11) #€iM€£.llTERATl)RLAARi'/ Founded by RICHARD A. PROCTOR. Vol. sxiv.] LONDON : MABCH 1, 1901. [No. 185. CONTENTS. Bv tho Ef>T. John "SI. Bv Geo. H. Exploring the Thunder Cloud. Bacov, f.r.a.s. {Illustrated) The Insects of the Sea. — II. Spring tails. C.^BPEN'TKU, IS.Si .Cl.OND.) (Illiislraleil) Rainfall in South Africa. B_v Arthcb II. Bbi.i. The Size of Ocean Waves. — II. By Vacoua:? Cobnish, M.SC.(VICT.), F.C.S., F.B.G.S Constellation Studies. — III. The Region ot Virgo. By E. Walter JiArxDKR, f.r.A.s. {Illustrated) Total Solar Eclipses of the Twentieth Century. By A. C. T). CROJfMEr.ix. (Illustrated) Sunrise on the Sea of Plenty. l!r V.. Wat.tkr Macndbr, f.r.A.s. {Illustrated) Sunrise on the Sea of Plenty. {Plate.) Letters : fng Path of the ^^rv. By AV^r. Santif.max ... SrssET Phenomenon. By R. L. Mf Donald Notes Notices of Books Books Kf.of.ivkd British Ornithological Notes. Conclurteil liy Uabhy V. WlIHBRET, F.Z.S., iT.B.O.C Finger-Prints as Evidences of Personal Identity. By R. Ltdkkker. [Illustrate:)) Microscopy. ComUutcd by if. I. Cross. Notes on Comets and Meteors. J3y W. F. Dennino, F.R.A.S The Face of the Sky for March. By A. Fowleb, f.b.a.s.... Chess Column. By C. D. Locock, b.a 10 5t 55 Cil C-J. r,:\ 63 64 (io 6(5 6!l 70 71 71 EXPLORING THE THUNDER CLOUD. By the Rev. John M. Bacon', f.r.a.s. Pebchaxce you have Iain awake in a draiiglity seaside lodging when the wind has been rising, and have heard a door in the house banging at intei-vals at the sport of the wind. Time after time it opens a little way and remains ajar, perhaps for quite a considerable period, when it abruptly " blows to " again. And this pro- voking performance goes on indefinitely with persistent monotony. The puffs of wind that are responsible for this annoyance, if in an incipient state, will often be found to recur with almost rhythmic regularity. The same phenomenon is noticeable enough out of doors on most days when wind is stirring, but being then less obtrusive generally goes unheeded. Sometimes, however, the gusts will come on with such impetuous force — like very explosions — that they cannot W ignored. The sailor at st\i calls them great guns, and I ho sailor by sky also learns to take heedful count of thorn. On a stormy day, during those ticklish few final minutes when a balloon is being '' weighed " and adjusted for the start, the heavy gusts that swcoj) past have to be promptly met, and it is fortunate that their on- slaughts are often sufllciontlv woll-tini(>d (o allow of their being fully o.xpotteil. It is no uncommon ovent for a thunder storm to arrive with one of these wilder squalls, and in this. case it is well known that tho motion of the storm as a whole is markedly slower than the average speed of the wind— - very commonly a shallow one -which bears it. On another occasion the cloud may bo found riding some upper and contrary current, and under these circum- stances gives apparent justification for tho popular saying that " a tluinder storm will come up against the wind." Once this last summer I chanced to bo aloft when a disturbance of this nature was brewing, and was able to note tho gathering of the storm from tho somewhat un- common point of vantage fiirniihod by a free balloon. July 27 last, was, at least for Newbury and twenty niiles round, a day that was characterised by such well marked regular gusts as I have referred to. It also became a typical day of summer stornis, and it should be mentioned that the nature of the weather indicated the passage of a well pronounced " secondary," such as is so commonly associated with thunder storms. It is fre- quently asserted that a characteristic feature of such storms is that the lower sweep of wind which circles over the surface of the ground is very shallow, while at only a moderate height overhead there may be a wholly different drift. This at any rate was the state of affairs as betrayed by the behaviour of tli(> storm I am able to describe. Before leaving the earth I had entered certain memo- randa in my note book, one of which runs thus:-—" All through the day weather cocks have been pointing E., while clouds estimated at 2,000 ft. altitude have been scurrying in an opposite direction. The first thunder storm broke over the town at 1 p.m. It was short> but severe, the thunder as heard in the main street being as deafening and prolonged as any that I can recall." Another note is to the effect that the oncoming storm approached from due south, and as it burst on our en- closure set the balloon, already filled, spinning in a direction contrary to that of clock hands. Several pilot balloons, which were sent up through the afternoon, and which became invisible before they had reached any great height, went sometimes S.W. and sometimes W., and seemed to hesitate between these two directions. At 5.15 wha), was apparently the clearing shower had passed over, and the sky was seen everywhere cloudless up to a great height, the wind on the ground dropping shortly to almost a dead calm. Had any cloudlet been left in evidence at a few hundred feet overhead, or had we at this juncture sent up another pilot, the ascent might have' been postponed, or at least the more ex- perienced among us would have altered their opinion about the " clearing shower." At 5.45 we cast off and leisurely took a N.W. direction heading for Swindon, and thus proceeded till we had covered rather more than a mile in distance, and risen about 700 ft. Ill height. At this point we abruptly came under the inHucncc of a well defined current which diverted our course to that of the Kennet Valley, trend- ing sensibly due west, and we closely followed up the line of this valley for many miles. ^, . ^ In scarcely more than twenty minutes from the start no KNOWLEDGE [March 1, 1901. a sudden and surprising change took place in our circum- stances. Our environment, which had appeared absolutely calm and clear, began changing with the rapidity of a transformation scene. Below us the few hundred i'eet that separated us from earth began filling in with a blue haze, quite transparent, but growing palpably filmier, while ahead, as also right and left, the horizon at the level of our eye and higher opposed a dense fog barrier of an ashen hue. Overhead of course the sky view was entirely hidden by the huge silken globe. At this period of time we were being swept along on our course, which remained sensibly unaltered in direction, at a speed which we were subsequently able to fix at approximately forty miles an hour. To ourselves the full significance of these circumstances was not immediately apparent, but the onlookers at our point of departure — the town gas-works, now some five miles in our wake — clearly detected the approach of a heavy thunder pack, and as they reasonably asserted coming against the wind. It towered above the balloon, now seen projected plainly against its face. It came on rapidly and assumed formidable proportions, and there was then the following state of things. The balloon flying due west at the high speed just recorded and, at for five hours continuously ; a little way on our right a house was struck and burnt to the ground, and on our left a couple of soldiers were killed on Salisbury Plain. I would call- attention to the fact that though the storm progressed, it also appeared to lag behind the wind that bore it along. I would also lay stress on the further fact that it did not seem to advance against us as a whole, but rather gathered aboiit us, forming itself out of what a few moments before had appeared mere empty and transparent air. "Very probably this gathering storm curtain was largely due to the sudden chill which now was very manifest in the air, and which obviously had its origin from above. In the depth below us there was no evidence of any special disturbance, and a para- chute dropped from the car about this period floated to the earth steadily and with no divergence. All this may be taken to lend confirmation to the theory that associates thunder storms with sudden and considerable alterations of temperature in contiguous masses of air. It is worthy of mention that 73 years before an ascent had been made from the same spot at Newbury by the famous Charles Green, under circumstances which it will be seen resembled in many particulars those of the Temperature acd Weather. 8 a.m. Frid.\t, 27tli JrLv. 8 a.ni. liarometer and AVind. 6 p.m. apparently no great distance overhead, the thunder cloud progressing at a moderate velocity, not accurately determined but due east or directly opposed to the surface current. And now with a whistle a blinding sheet of hail attacked the aeronauts, stinging their faces so sharply as to give the idea that the stones were falling from a great height, and immediately afterwards from all sides and close around flashes of lightning shot out with remark- able frequency and vividness. We were, in fact, fairly embosomed in the thunder cloud. Other and near observers nan^owly watched the phases of phenomena now in progress. These were the countrymen who became interested spectators, and who presently came to our assistance. They seemed to have imagined that the balloon must be infallibly struck, inasmuch as it appeared to them completely encircled with lightning. It was indeed the worst storm the country side had known for many years. At Devizes, only a few miles ahead, it lasted I h,l II,.- i)/f(...™("r|'l"' O.tfcC. present occasion. The clay was marked by squalls and the ascent postponed until the evening, when the storms gave signs of having cleared ofl". This appearance, however, was illusorj', and the aero- nauts presently encountered a thunder storm, the balloon, which liad attained an altitude of two miles, being above instead of below the -^torm cloud. Mr. Green thus describes the situation: — "At this altitude we perceived two immense bodies of clouds operated on by contrary currents of air until at length they became united, and at that moment my ears were assailed with the most awful and long continued peal of thunder I ever heard. These clouds were a full mile below us." This i-everboi ation of the thunder is worthy of a little consideration. It is to me intelligible enough when it is remembered that the source of sound lay between the balloon and the earth, in which case it only resembled the artificial thunder which 1 have offer? evoked by Sl\Rcn 1. 1901. KNOWLEDGE 51 explosions of gun cotton. In our own experience just cited, however, tlie lightning flashes which appeared to coui-se between cloud and cloud rather than between cloud and earth were like typical mountain storms fol- lowed only by a single short report, and in this resembled phenomena twice observed by Mr. Wise in America. This observant aeronaut on two separate occasions speaks of thunder as " rattling like small arms without any of the rolling reverberations that are heard below.'' But another significant observation was made by Mr. Wise in both his experiences just referred to. " The thunder pack itself developed uprising cloud columns whose motion resembled that of ebullition in a vast cauldron from whence electric flashes were discharged." With almost the same language he describes the effect presented to him on each occasion when he approached from aloft the neighbourhood of a thunder storm ; and Mr. Green in his Newbury ascent already alluded to, uses words that are hardly dissimilar. " I observed,'' he says, '' among other phenomena af every dischai-ge of thunder all the detached pillars of cloud within the distance of a mile round became attracted and appeared to concentrate their force towards the first body of clouds, leaving the atmosphere clear and calm beneath and around us." Neither of the above bvgone aeronauts describe to my knowledge any occasion when they have actually found themselves in the heart of a thunderstorm, and in our own case, had there been but fair warning, I think there would have been but little difficulty in avoiding the storm by simply rising above it; but, as I have already sufficiently explained, we were practically with- out warning from the peculiar manner in which from our restricted point of view the thunder cloud seemed to develop about us out of thin air. I do not imagine that the smart impact of the hail stones necessarily proved that their origin was far over- head. It is my impression that the hail was being forcibly swept down upon us by a violent downrush of icv air, and as we were counteracting the descent of the balloon by a discharge of ballast our own motion would not reduce the pelting of the storm. It needs no pointing out that hail is chiefly a pheno- menon of the warmer hours of a summer day suggesting that warm moist currents are answerable for its formation, and in this view we may fairly regard the thunder cloud itself as its cradle, and this very fre- quently at no higher altitude than a mile above the surface of the ground. The tendency of hail to form with exceptional fre- quency and severity over certain ai-eas is a local pheno- menon which has perhaps hardly met with the attention it deserves, but no facts are more striking or better established. In KxowLErcE some years ago it was stated that '' within a radius of 12 miles round Somersham Railway Station Tfluntingdonshire) hailstorms are so fre- quent and destructive that all the insurance companies charge double the ordinary rates per acre for crops giow- in? within that district.' The general meteorological conditions prevailing at the time of the storm above described are given in the accompanying charts. . — ♦ THE INSECTS OF THE SEA. II. Bv Geo. H. Caepenter, b.sc.(lond.), Axuintant iti the Mmeum of Srience mul Art, Diihlln. SPRING-TAILS. " Wh7 the Collembola should be neglected," wrote Dr. Sharp,* in 1895, " when the Thysanui-a attract so much attention, is as inexplicable as many other fashions .ai'e." During the last few years, however, the Spring-tails or Collembola have been receiving a fair share of attention from naturalists, and it seems that the entomo- logical fashion to which Dr. Shai'p referred, is destined to show its likeness to other fashions by experiencing a marked change in the near future. The naturalist by the sea-shore at least ought not to neglect the Spring- tails. Smaller and less conspicuoiis than the Bristle-tail, Mnrhiliit inarifiiiia (described in KNowLEncE for January), the marine Spring-tails may be, but they are fairly luimcrous in species, and some of them arc more perfectly adapted than Machilis for a marine life. Spring-tails resemble Bristle-tails in being entirely without a trace of wings, and have often been united with them in the order "Thysanura (to which it has lately been suggested to restore the Linncan title Aptera). But the divergence between the two groups is in many respects so striking that Lord Avcbury's scparationf of the Spring-tails as a special order, to which he a])plied the name Collembola, seems to be fully justified. The name (KiA/.a, i/liii', and Ja/SoX?) ii /liniin'ng in) refers to the supposed function of the " ventral tube " — a very characteristic organ of these insects, situated beneath the first segment of the hind body (Fig. 1, v. t.) ; it shelters two protrusible processes which may help the insects to cling to smooth surfaces, or may possibly, like the abdominal sacs of Machilis, serve as breathing organs. This tube is unknown among the Bristle-tails, and there are other and more conspicuous differences between the two groups. The hind-body of a Spring-tail has never more than six evident segments, and long " tail-bristles " like those of the tenth abdominal segment in the Tliysanura are never present. The feelers, always with very numerous segments among the Bristle tails, have never more than six distinct segments among the Spring-tails. The reduction in the number of abdominal segments from ten to six marks the Spring-tails as a less primitive group than the Bristle-tails. And their specialization is further shown by the possession of that very remarkable organ — the " spring " — which gives them their English name. The spring (Fig.l, .s), which may be borne beneath either of the fourth or fifth abdominal segment, roughly resembles a two-pronged fork, consisting of a single basal piece— the " handle " {niavnhriinii), to which arc attached two long, flexible tapering "teeth " (denten) ; at the end of each tooth is articulated a little " point " or tip {tinicro) which is not always sharp. It is likely that this spring has been formed by the fusion of a pair of abdominal limbs. It may be tucked beneath the body pointing forwards, as the insect runs along; when it is released and straightened out so that the tip points backwards, the Spring-tail leaps into the air. Let the reader lift a stone under which a colony of Spring-tails are sheltering, and he will have full demonstration of their leaping powers. (See Fig. 1.) There is a family of Spring-tails, the Sminthurida;— having, however, no"^ marine representative— with compact globular hind-body ; these insects breathe by means of a set of air-tubes opening by paired air-holes on the head —an altogether exceptional position. But most Spring- tails have no air-tubes at all; they breathe entirely through the skin. Adaptation to an aquatic lifejs, * " The Cambridge Natural History," \'ol. V., p. 190. t Sir Jolm Lubbock. " Monogi'aph of the Colleml)..]^ and Thysanura. London {.Uay Socie/i/), 1873. KNOWLEDGE. [March 1, 1901. therefore, easy to them. Many species are found on the marshy shores or ou the surface of the waters of lakes and pouds. and quite a fair number will reward the re- searches of the seaside entomologist. Several species of the genus Isotoma, for example, may be found jumping about among the cast-up seaweed at highwater mark. Some of these are of interest since they occur indifferently in inland and sea-shore localities. Isotoma belongs to the Entomobryidse — the most typical family of the Spring-tails — characterised bv a well- developed spring (borne on the fifth abdominal segment), a very small front fore-body segment (prothorax). and a clearly segmented hind-body. The species of Isotoma are not scaly as many Spring-tails are. but are clothed with numerous hairs, sometimes also with bristles. The hind-body segments are equal in length or almost so. Isotonui pahiffris (Miiller) is one of our commonest Spring-tails, occuning among herbage in marshy places, and by the edges of ponds. But this species may also be found among seaweed, and a dark, violet-brown variety, haunting the coasts of the Baltic, has been named fuciroln by Di's. Renter and Schott.j This par- ticular variety, however, is known to occur in Scotland by inland bogs. Such indifference on the part of the same insect to marshy or sea-shore surroundings is highly instructive, for it shows us a Spring-tail of the land in the act of establishing itself along the tidal margin. Isotoma Ufforalis, described by Prof. Moniez.§ from the French coasts of the Channel, is probably a form of this species. " It is very common," he writes, '' under the fucus which clothes the rocks uncovered at each tide. It runs very quickly beneath this shelter, leaps with the greatest ease, and takes refuge readily among the fronds of seaweeds or the shells of barnacles, when it is dis- turbed.' Fia. 1. — Isotoma maritima. Magnified 25 times. (*. spring ; r. t., ventral tube), a, foot-claws j b, tip of spring, magnified llo time'^. Another, much rarer Isotoma, 7. mnritimri. Tullberg ^Fig. 1). fust discovered on the Swedish roast, has lately been found both on the eastern and western shores of Scotland by Mr. W. Evans.|l The teeth of the spring in this species are veiy long and slender; if the end of the tooth be examined under the microscope, the thin pointed tip, and the long stiff bristle characteristic of the species can be made out (Fig. 1, I). I. maritima occurs on the shores of the Baltic, the North Sea, and the French coast of the Channel, but, despite its name, it is not exclusively a maritime insect. It inhabits Bohemia, and the Bohemia 1 H. Schott. 'Zur Svsteraatik und Terbreitung palfparctiseber CoIIembola." Kongl Svensir. Alad. Eandl., ToL'SXT \o 11 1893, 100 pp., 7 pis. § R. Moniez. " Acariens et Insectes marins dcs Cotes du Boulonnais." Ser. SioJ. .V. France, Vol. II., 1890, pp. 324-6. G.H. Carpenter and W. Evans. '' The CoUembolaandThvsanura of the Edinburgh Distriet." Proc. S. P/,i/s. Soc. EiHn Vol" XIV 1899, pp. 221-266, pis. Y.-VIII. ' , . . .. of modern geogiaphy, unlike that of Shakespeare's " Winter's Tale," has no sea-coast. Here, it seems, we have an insect, already almost restricted to the shore line, but still lingering on in the heart of the continent. Two other scarce shore-haunting Spring-tails Imtomn irii.- .a 4 >- < 485-6 Ratio Leugth to Height. Av. Period. Sees. Tree-grosse mer . . . 93-51 56-43 1-66 25-43 19-1 8-6 Grosse iner 65 62 45-93 1-43 16-57 347-8 210 7-6 Mer dure, elapo- teuse, fatigante, etc 43-96 41-01 107 11-65 252-6 21-6 6-2 Grosse houlc 30-18 45-28 0-67 1 3-45 ■393-7 29-3 8-7 Houle 19-36 39-04 0-50 7-87 255 9 325 6-5 Belle mer 18-70 35-43 0-51 525 203-4 38-7 5-7 the observations of the whole 4000 waves. In Table II. the grouping is without regard to locality, being 5t) KNOWLEDGE. [March 1, 1901. simply according to the " state of the sea." Only the mean values are here reprodiicod from the original Table III. Observations by Lieut. Paris. Region. V 1-0 .5 3 1^" &s ^i >d -3» 6^ .25 O u ■ O I, «>■ >i >-b «o 1 > 4) (,0) *t! ya. -K^ '^ ' 1 hr O a> ei K M 5 1 d ■S ^ >-l Atlantic Trades . . 1575 36-75 0 43 6-23 213 3 35-2 58 South Atlantic (Region of the West Winds) .. 44 29 45-93 096 14-11 436-4 310 9-5 Southern Indian Ocean 5709 49-21 1-16 17-39 374-0 21-5 7-6 Indian Ti-ades ... 21-33 41-34 0-52 919 315 0 35-3 7-6 Seas of China and Japan 47 90 37-40 1-28 10-50 259-2 24-7 6-9 Western Pacific... 27-89 40 68 0-68 10-17 334 7 33-0 8-2 • This columu canuot be calculated from the two preceding columns. table. In Table III. the same observations are grouped geographically. The first question -which occurs to one is -whether another cruise -would give similar -waves in the same areas. Fortunately -we can compare the heights of the waves -with those observed (about 1837 a.d.) on the voyage of the Astrolabe, of -which a summary was published in 1866 (Compter rendus ties fiances de /'Acad, den sciences. Vol. LXII.), by M. Coupvent des Bois, -who -was himself a member of the expedition. The method of observing the height of the -waves -was the same as that adopted Ijy Paris. The velocity of the -wind is also given but does not seem to be comparable with Paris' numbers. The verbal description of the state of the -weather is, however, some guide in this case. (Table IV.) The average heighti of the waves in the trade winds of the Atlantic Table IV. Observations on the Astrolabe Velocity of Scale of Wind. ^um-bers. State of Weather. Feet per Mecond. 0 Calrae mojen 3.28 1 Faible brise 9 84 2 Petite brise 16 4 3 .Tolie brise 26-25 4 Belle brise 42-65 5 Forte brise 689 (> Grraud fnUs 108-27 7 Tempi' te 164 04 8 Uuragan 239 31 It will be noticed that vclocitie." for strong winds arc quite uut of accord with Paris' determinations given in Table I. and Indian Oceans is very nearly the same in the two cases. The lai-gest waves were met with on both voyages in the southern Indian Ocean. The results for the Pacific Ocean differ much ; I doubt, however, if the area included by Paris under "Pacific west," is the same as the western part of the " Oi-ean Pacifique eijuatorial " of Des Bois, so that the difference of results may have but little jjhysical significance. Des Bois' method of grouping the waves in longi- tudinal strips of 30° is convenient. In the equatorial Pacific (0° to 30° lat.) the mean force of wind and the mean height of the waves diminished from east to west, being near the Asiatic coast only -| to ^ of the height near the American coast. In the equatorial Indian Ocean the winds and waves were highest in the middle. In the equatorial Atlantic the waves were highest on the western side, although the winds were strongest in the east. In the centre there was a medium height of wave combined with the lowest force of wind. In the latitudes 60°-66O S. we note the strongest winds with relatively low waves. I suspect that the relatively small height of wave is due to floating ice. which, as Norden- skiold has pointed out, has a marked effect in smoothing the sea. The total number of observations was about 7200. I infer from the text that the height of the waves was not actually measured at each observation, but that suificieut measurements were taken to satisfy the person resjjonsiblc for the work as to the height of wave which corresponded with the entry " state of the sea." This state of the sea was noted six times daily, each such note constituting, I suppose, one " observation," from which the average heights given in Table V. were afterwards Table V. Observations on the Astrolabe. Compare last column with column 4 of Table II. Velocity of Wind. Feet per Second, I*^iliiaiorial Pacific Ocean (00—30° lat.) Kquatoi'ial Indian Ocean (0"— 30" lat.) Equatorial Atlantic Ocean (0°— 30 lat.) 30°— 50' 50"— 60° S. 50=— 60° S. 60° -04 S. 60°— 66" S. 75-l](,w 110 140 „ 140-170 „ 170w.1G0e: 1 60-1 30 E 130 100,, 120-90 „ 90-60,, 60- 30 „ lOK.-llw. l(i\v.-30 ,, 30-50 „ .111 longi- tudes Meridieu [ d'Amerique Meridien NouTelle- I HoUande ! Meridien d'Amerique Meridien Nouvellc- HoUande 1.5-42 "-I 13-45 19-14 av. 15-75 11-11 15 09 "1 I 1903 i- ay. 17.00 24-94 23-95 Uv.24 45 Height of Waves in Feet. 11-48'^ 6 56 I ^■''H-iv .5-69 3-94 r 3-94 I 3-28J 6 89 ■) 11-81 ^iv. 8-42 6-56; 4-20 ) 6-56 [. ar. 6-12 7-55 ) 7-22 6-89^^ I 14-44 l-av. 10-67 6 891 6 89 I- av. 6-89 1 J calculated. This connection between " state of the sea " and height- of wave, found by measurement, is given in Table A' J. Tliis should be com])ared with Paris' Table 111. The following observations of waves were made by the Hon. Ralph Abercromby* on board the s.s. Taii- gariro, in various parts of the South Pacific, between New Zealand and Cape Horn, in 1885. The observations of height were made with the aid of a 4A inch aneroid, with a very open scale divided to 0.01 of an inch. Altitudes were calculated on the assumption that 0.001 inch difference of pressure corresponds to * Observations on the Height, Length, and A'elocit.v of Ocean Waves, read before the Pliysical Society, February 25th, 1888, published in tlie Phitosophical Magazine, April, 1S88 (Vol. XXV., 5th Series). Makcii 1, 1001.1 KNOWLEDGE. 07 1 foot height. It was considered that the errors of height due to tho aneroid were never more than 2 to Table VI. Observations on the Ai'tritlnhc. Number!! reoorvleU in the Log. I >t;UO of S<>rt. Hoisht of Waves in Foct. Tr^s-grosse nier Grosse mer Tivsgrossc lioulo Grande lioule Iloule Petite houle Belle mer II pr unie 28-5-t 20 67 loi2 10-83 7'85 ■1-92 3-28 197 Compare with eolunins 1 and "i of J'lilile IF. 2.5 feet. The greatest source of eiror in the opinion of the observer occun-ed in the estimation of the height of the eye above sea level. For instance, he says, when the aneroid was at its lowest point the surface of the water might be 10 feet below the eye; but when the crest of the wave was passing, the height might be I'educed to 1 or 2 feet. Here the observer had lo trust to estimation by the eye aided by a few i-ough measiu'ements with a piece of string down the ship's side, end tho error here, he considers, may be at least 2 feet either way, or 4 feet in all. Observations for length and speed were taken in much the same way as those of Paris, witli the advantage, howevei', of a flyback chrono- graph over an ordinai-y seconds hand watch. Aber- cromby mentions two difficulties in obtaining good results, viz., that two successive waves rarely ran in exactly the same direction, and that, with a heavy following sea the ship yawed' about so nuieh that the angle between her course and that of the waves could only be estimated approximately. Really big waves were met with on only 3 days. On June 8th, 1885, in lat. 47° S., long. 175° W., the sea was too irregular to measure individual wave heights or lengths, but the barometer indicated about 12.5 feet vertical motion of the point of observation below decks. The surface of the sea was pretty constantly about 7 feet below the porHiole in the troughs, and 1 foot at the crests. This gives an average height of the waves 18.5 feet. The velocitv of the waves was pretty constant, although the length appeai-ed to be so irregulai", five observations giving speeds of 29, 28, 31, 33 and 30 miles per hour (average 30.2 miles). On June 10th, in lat. 51° S., long. 160° W., the observer availing himself of the previous determination, assumed a constant dif- ference of six feet between the height of the aneroid above water level at crest and trough, and added this to the observed variation of the aneroid. Individual waves were observed with heights of 26, 21, 23.5 and 26 feet, but the indication of the aneroid indicated that the difference of absolute level between the lowest trough and the highest crest (not one of those recorded above) was 35 feet. I suppose the inference from this to be that the difference, if a real one, was due to the presence of a long swell susceptible but not visible in tho rough sea, and I apprehend that the revelation of such invisible but not negligible waves is one of the special advantages of the aneroid over eye observation. The velocity and length of waves was meastired just before the heights were taken ; three determinations gave the following residts : — • Velocity. 32 iuilo9 poi' liour. 3.-, 39-5 285 Lonirtli. 507 foot. ■170 ,» 3.-,S „ Velocity. 35'5 miles ppv hour. 35-5 -l-"-5 This sea, Abercromby says, would Iiavc been logged as 6 or 7 on the ordinary scale of 0 — 8, while tho wind was blowing a moderate to hard gale from N.Vv''. v.-ilii heavy squalls, and was logged 7 on Beaufort's scale of 0 — 12. During some of the squalls the force rose to 8 ; tlic sea, he says, might be taken as a fair average in the South Pacific, the waves were far too irregular to allow of any attempt being made to determine the ratio of height to length or velocity. On July 16th, 1885, lat. 55° S., long. 105° W., larger waves were observed during which the greatest vertical lift of the aneroid in tho cabin was luidoubtcdly 40 feet. If tho difference of water level outside was again 6 feet the height of the waves was 46 feet, but of this the obsei-\'cr, who confined his attention to the aneroid, was not sure. Tlio mo.Tsurcd velocities and lenijths were : — I.eiia-th. H5 feet 48.-1 „ 7(i5 „ The author states that the want of harmony botwcon the length and velocity on the one hand, and tho height on the other, was not duo to errors of observation. On all the days tho waves were running irregularly ; ho did not see any crests nearly a mile long chasing one anotlier with a well defined trough between. There was nothing to call a cross sea, but there were many scries of waves of different lengths manning pretty much in tho same direction which were constantly interfering with one another. He generalises from his experience (which it must be mentioned were by no means confined to the voyage of which he here speaks) in the statement that the great discrepancies in the observed elements of waves given by different observers is doubtless duo to the co-existence of several series of undulations, which, tlierefore, always make a more or less confused sea. The author concludes with suggestions for a wave- measuring party, which he says should be composed of tlu-ee members. A, B. and C. C would have charge of two chronographs, and B of the aneroid. They would confine their attention to reading the instruments, whilst A only would watch the sea. He would observe the arrival and passage of the wave crests, the height of the water against the ship (by marks on the side) at crest and trough, and ho might have to read a simple clinometer also to allow for the roll of the ship. (To he continued.) CONSTELLATION STUDIES. By E. Walter Maunder, f.r.a.s. III.— THE REGION OF VIRGO. TuE Great Bear still holds the zenith at midnight throughout the month of March, but by the middle of the month the Lion has ceased to be the dominant constel- lation in the south. Its place is taken by the Virgin, which seems almost to lie below the royal beast, for at this time of the year tho ecliptic curves downwards more sharply than at any other period, for its descending node lies close to the boundary of Leo and Virgo and just within the latter constellation. Virgo, therefore, is easily found when Leo is known, or the old rhyming direction will plainly point it out ; — 58 KNOWLEDGE. rM.\BCH 1, 1901. " From the Pole Star through ilizar glide \ TVith long and rapirl flight, Descend, and see the Tirgin's ?pike Diffuse its rernal bjjht, And mark what glorious forms arc made By the sold harvest's oars, With I'eneb west Areturus north, A trioDgh- appears; " Denebola of the Lions tail forming an equilateral triangle with Arcturus and Spica. the principal stSr of the Virgin. The chief stars of the \'irgin, six in number, make an iiregular capital Y, lying on its side, the stem and lower branch of the Y very nearly marking the ecliptic. That great circle is particularly clearly marked out in this portion of the heavens. Delta in the Twins,^the bright star below Pollux, and marking that hero's right hand ; Delta in Cancer, the southern of the two ass:s; Regulus spirit of Justice, once in the Golden Age a dweller amongst men. But when an inferior race in the Silver Age succeeded to their fathers, she withdrew to the mountains, and fled thence to the sky when the Brazen Race fashioned murderous weapons and devoured the flesh of plough oxen for their food. The account of her which is still most generally received, is that she repre- sents the wheat harvest ; the ear of corn in her hand, which one would have thought a fitter symbol of sowing, being taken as representing the garnered sheaves. But this cannot be the case, for Aratus tells us — '■ As rushins on his prey, The lordly Lion greets the God of day, ^Vhen out of Cancer, in his ton-id car Borne hiah. he shoots his arrows from afar, Scorching the empty fields and thirsty plain. Secures the barn the harvest's gnl-lpn grain ; " proving, as Brown points out, that Spica was not asso- VIRGO '-pcn / ^' VELA NORMA =$0 ■*.? * ■« XVI XV m XII XI IX Star Map Xo. 3 ; The Region of Virgo. ill Leo are all almost exactly on the ecliptic, and Rho and Tau. two fainter stars in Leo, cany on the line to the boundaries of Virgo. Within that constellation the line runs a little south of Beta. Eta. and Gamma, which form the right branch of the Y, and a little north of Spica (Alpha Virginis). Whilst a fourth magnitude star. Lambda, as far beyond Spica as Spica is from Gamma, marks almost the precise point where the ecliptic runs into Libra. The upper branch of the Y is marked by Delta and Epsilou. Gamma the star which marks v.-here the Y forks, is one of the most celebrated of double stars. Aratus gives more space to the history of this constel- lation than to anv other. With him. she is Astraea, the ciated originally with the harvest, since this had been already reaped when the sun entered the Lion. A further proof is afforded by the old name of Epsilon Virginis, " Herald of the Vintage," the vintage neces- sarilv falling considerably later in the year than the harvest. I The constellations of the Zodiac, if intended to mark ! the several months of the year, should, being twelve in number, stretch each of them over 30° of longitude neither more nor less. As a matter of fact they are of most irregular length. Cancer extending only over 18° or 19°, whilst Virgo covers about 50°. At an early period, therefore, the ecliptic was divided into twelve cqtial portions, not constellations, and having no direct con- Makiu 1, 1901.] KNOWLEDGE. !) noctioii with the actual arrangement of the stars, but deriving their names Jroru the constellations which niosl nearly corresponded to them. These were the Signs of the Zodiac as distiugnishod from the Constellations of the Zodiac, and the distinction between the two is ono that it is important to bear in mind.- The months of the year never did, and never could have corresponded with the actiuil coustellations ; the Signs, being purely arbitrary divisions, could always be made to correspond with the months. Since, then, the constellation figures arc clearly older than the equal signs, it is manifest that none of the many sihcmes which have been framed to account for the Signs of the Zodiac by the climatic changes of the successive months in this or that country can have any basis in fact. The con- stellation figures were in existence long before tl\e cor- relation of signs and months w-as effected. The Accadian calendar connects the sixth sign of the Zodiac with Ishtar, the " daughter of heaven,' the moon in one aspect, and tlie planet Venus in her two-fold ^p DRW^O . • • • tAlMOR cS^' 5-* .^■-^ •-.. » \ * '■i.-ir. ; • . CORONA oRs^^^f . : : ■ '^^ -J Tlic Midnight Sky for London, I'JOl, Marcli 7. character oi* morning and evening star in another. Early Christian thought recognized a reference to the premiss of " the Seed of the Woman " of Genesis iii. 15, in " the ear of the corn " the Virgin carries in her hand, and the expression in Shakespeare's play of Titus Audronicus, '■ the good boy in Virgo's lap," refers to the mediaeval representation of the sign as the Madonna and Child. The region of the sky enclosed between the two arms of the Y, and Denebola of Leo, lies near the pole of the Galaxy, and is the wonderful Nebulous Region. Here these strange bodies are to be found by the hundred, clustering more thickly than in any other portion of the sky. Close below Vii-go arc two small but fairly bright con- stellations, the Cup and the Crow ; the Cup lying under- neath the Virgins shoulder, the Crow beneath her hand. The latter constellation is very easily found ; Delta Corvi foi-ms with Alpha and Gamma Virginis almost an equilateral triangle, and the line from Alpha Virginis to Delta Coi-vi leads to Gamma Corvi. When on the meridian two other stars of about equal brightness, Epsilon and Beta, lie below Gaiiuiia and Delta and make up with them a neat liltle trapevnuni. Beta Virginis and Delta Corvi make a rotigh equatorial triangle witli Delta Crateris, the brightest star in the centre of the Cup, a somewhat fainter group than that of the Crow. Four stars in a semi-circle, of which Delta is the middle one, mark the bowl of the Cup. These two little groups are commonly represented as actually intermingled With a huge, winding snake, the longest constellation in tho sky. Hydra, which stretches across some 9.')° of longitude. Its head begins close to Procyon, under Cancer, and it stretches below the zodiacal constellations of Cancer, Leo and Virgo and the greater pari, of Libra. It has few bright stars, and these not grouped in easily remembered figures ; and the great reaches of barren sky it includes seem referred to in the name, given to its brightest star, Alphard, The " Solitary." Alphard may be readily found by prolonging a straight line from Gamma Lconis through Regulus, and dropping a perpendicular on it from Procyon. The myths connecLed with the three con- stellations have no very great interest. Brown finds Hydra, a " storm-and-oceaii-monster." " The quick flow- ing rivers seem to have been compared by the Akkadii with the swift gliding of a huge glistening serpent, and so we arrive at the idea of the Kiver of the Snake, which develops into an Okeanos' stream, like the Norse great serpent," the Midgard Snake, The Cup becomes thus a " symbol of the vault of heaven wherein at times storm, wind, clouds, rain are chaotically mixed " ; and the Crow, or rather Raven, is the constellation of the Storm-Bird, Carl G, Schwartz, who, at the beginning of this century interpreted the constellations as being a sort of symbolical geography of the countries on the west shore of the Caspian, thought these three constel- lations represented the petroleum wells of Baku, The great extent of the Hydra, with its folds and knots, show, beyond mistake, in his opinion, the slow oily flow of crude "ptiti-oleum; the Cup is placed there to indicate the liquid which would have to be held in a cup or some such reservoir, whilst the Crow indicates its inky black- ness ! Of I hcse three constellations. Crater is perhaps the best for opera-glass examination, yielding some pretty fields, Zeta Corvi, the faint star nearly midway between Epsilon and Beta, shows with the opera-glass as an interesting little double, whilst a much closer pair will be found near Beta and slightly preceding it. EKKATPM,-In column 2, page 3-1, of the Fehrmu'v numboi- of Knowledgb, the eighth line from the bottom is to be omitted. TOTAL SOLAR ECLIPSES OF THE TWENTIETH CENTURY. By A, C, D. Crommelin, Stanbing as we do on the threshold of a nev/ century, it seems a fitting occasion to examine what opportuni- ties it will afford of witnessing that grandest of celestial phenomena — a total solar eclipse — and of unravelling the mysteries which still hang thickly about the sun and his surroundings. It is clear that eclipses visible iri Europe are especially interesting to us, for they are accessible to a much greater number, and afford opportunity for more complete series of observations, I have prepared a diagram showing the tracks of all the total eclipses that cross Europe or the regions adjoining it during the coming ceatuiy. These tracks do not claim absolute accuracy, but they arc vei7 near the truth. I have in 60 KNOWLEDGE. [Makch 1, 1901. each case calculated as many points as seemed necessary from the Tables in Oppolzer's Canon, and then drawn the track throus;h them by hand, except for the eclipses of 1914, 1927, 1999, for which I have made nse of the elements givsn by Dr. Hind in " Nature," Vols. XII., XIII., XXXI., and that of 1905, for which I have made US3 of a map published by the Madrid Observatory. Two European countries seem especially favoured at present, viz.. Spain and Norway. Spain has had total eclipses in 1842, 1860. 1870: "it had one in the past year, and others in 1905. 1912. Xorwav has had them in 1816. 1851, 1896, and has others in 1914, 1927, 1945, 1954. I commence with the eclipse of August 30th, 1905, which is a very favoiu-able one, ths track being 2 J times as broad and the duration 2i times as long as that of the past yeai'. track but annular at the beginning and end. The track enters Portugal near Aveiro and runs north-east, leaving Spain some 12 miles east of Gijon. It then traverses France, passing very near Paris, and across Belgium, Germany and Russia. In Portugal there will be about 7 seconds of totality, in the west of France a second or two, and further east the eclipse will be only annular. Short as the totality is m Portugal it should be pos- sible to obtain photograpiis of the inner corona, and the flash spectrum may be photographed round the whole limb of the sun, which should yield results of great interest and value. The eclipse of 1914 ciosses Norway, Sweden and Russia. The central line enters Norway at Alstahoug in latitude 66°, the duration of totality being two miuutts. It runs south-east, intersects the railway running cast fi-om Trondhjem, leaves Sweden near Bramon I., Diagi-am showing the Tracts of all Total Solar Eclipses that cross Europe dui'ing the Twentieth Century. The central line run.'-, from Viavclez in Oviedo to Torreblanca, passing close to Burgos, which will be a very convenient and accessible station to view it from, the dui'ation of totality there being 3m. 47s., a very unusual amount for a European eclijase. The width of the track is about 120 miles; the southern limit runs approximately from Corunna to Valencia, the northern one from a little west of Santander to somewhat south of Tarragona. This eclipse may also be observed in Labrador, the Balearic Isles and Tunis. Passing over the eclipse of 1907, which is total soon after sunrise on the shores of e Caspian, wc come to that of 1912. This belongs to that rather rare class of eclipses which are total neai' the middle of the shadow intersects several islands in the Baltic, and then takes a course across Russia from Riga to the Crimea. Those who journey by sea have ttus the choice of four distinct coasts, in addition to the islands. The eclipse of 1916 ends near the south coast of Ire- land. The track of totality passes very near to, and may actually intersect, the island of Corvo in the Azores, so that this may be available as an obsei-ving station. If not, it will be necessary to go to Guadaloupe or Venezuela. The eclipse of 1921 is inserted in the map, though only an annular one, since it is the next central eclipse in the British Isles. The last total eclipse in the British Isles was in 1724, but there were annular eclipses in March 1, 1901.1 KNOWLEDGE. 01 1S36, 1S47, 1S58. The ceutval Hue in 1921 crosses the island of Lewis, aud ouw.irds to the Lofodeu Islands. The eclipse of 1925 is tctal near Boston, U.S.A., but docs not appear to touch land on this side of the Atlantic. In 1927 we have the next totality in the British I.slcs. The central line runs from near Anglesea to North Yorkshire, where totality will last about 21 seconds. Dr. Hind gives it as nine seconds, but this seems to me to be clearly too small. The track then goes right up the backbone of Norway, and passes out near Yadso, which was occupied as an eclipse station in 1896, and may again be occupied, as the duration of totality there is considerably longer than in southern Norway ; our weather experiences m 1896, however, were not very encouraging. The eclipse of 1936 may be well observed from Con- stantinople; that of 1915 from Nonvay, Sweden or Finland. In 1954 we may have another totality in the British Isles, as Dr. Hind considered that the northernmost of the Shetlands would lie within the shadovi^ track ; in any case it will be observable in southern Norway.* The remaining eclipses do not need much comment. The eclipse of 1961 may be well observed in Italy and Turkey. In 1966 there will be a very brief totality in Greece. It is not shown on the map. In 1999 occurs the third totality of the centiu'y in the British Isles, and the most favourable of all. The north limit of totality passes approximately through Tintagel Head, Exmouth and Weymouth ; the central line from St. Ives (Cornwall) to Prawle Point. Hence the shadow will cover nearly the whole of Corn- wall and the southern portion of Devon. The duration of totality will be just two minutes. This eclipse will also be visible in North France (the central line runs from St. Valery to Laon), Germany, Austria and Turkey. Many interesting illustrations of the Saros cycle or period of 18 years 11 days, after which eclipses recui', may be derived from oiu" eclipse map. This cycle was explained in an ai'ticle by Mr. Walter Maunder in Knowledge for 1893, Vol. XVI., p. 181. Each recurring eclipse moves westward about 120° of longitude, so that after 54 years we get an eclipse in about the same longi- tude, but north or south of the first according as the Moon is at a Descending or Ascending Node. The eclipses of 1882 (Egj'pt), 1900 (Spain), 1918 (United States), 1936 (Greece), 1954 (Shetlands), are an example of an eclipse moving slowly northward. Again, the eclipse of 1860 was visible in Spain; after three more Saroses it crosses Norway in 1914, while three more bring it to north-east Russia in 1968; after one more return in 1986 west of Iceland this eclipse ceases to be total.- As an example of a southward moving eclipse, that of 1851 was total in South, Norway ; after three Saroses it crosses Spain in 1905, while in 1959 it will cross the Sahara. Again, the eclipse of 1927 returns in 1945, and after three more Saroses it givss us that of 1999. While conveying a general idea of the locality where an eclipse will recur, the Saros is not exact enough to predict the track of a futui-e eclipse with great precision. Major-General Strahan, in his report on the Indian eclipse of 1898, attempts to predict the eclipses of the next century by the Saros cycle alone, but many of his tracks {e.g., 1961) are considerably in error. It would be useless to completely classify the non- European totalities for 100 years, but the more impor- tant eclipses of the next 30 years, some of which have been already mentioned, arc given in the following list : — 1901. Mauritius, Sumatra, New Guinea (long totality). 1904. Pacific Ocean (long totality). 1905. Labrador, Spain, Tunis, Egypt. 1907. Caspian, Turkestan, Mongolia. 1908. Pacific. 1911. Pacific. 1912. Soutli Aniei-ica (Bogota to Kio Janeiro).* 1918. North America (Vancouver to Florida). 1919. Brazil, Gold Coa.st, Lake Tanganika (long totality). 1922. Australia (long totality). 1923. North America (San Francisco to Jamaica). 1925. North America (Lake Superior to Boston). 1926. Victoria Nyanza, Amirantc Islands, Sumatra. 1929. Sumatra, Malay Peninsula, Philippines. The next thirty yeai-s afford on the whole a more favourable series of eclipses than the last thirty years, and as many of them arc in reasonably accessible locali- ties, it is to be hoped that they will be extensively observed, and unravel many problems of solar physics that are still veiled in mystery. * I -,1111 inliinijiii 'rp\ Eev. S. 3. Juiiu-.m luat iJl-. Iliii.l ■.iiij?.-..i.i.;liily foncludctl that the shadow would not touch the Shetlands, but would lie fiiHl.^"- \..rt1i. SUNRISE ON THEvSEA OF PLENTY. By E. Walter Maunder, f.r.a.s. The region of the Moon shown in the present plate, which is taken from the fourth number of the magnifi- cent Atlas Photographique de la Luue, published by the Paris Observatory, exhibits under the double influence of strong foreshortening and sunrise illumina- tion, a striking amount of relief; and the nearness of the terminator to the limb accentuates a feature, common indeed to the whole lunar surface, but here seen most strikingly, namely the tendency for the chief formations to dispose themselves along meridians. Thus we find the narrow strait of light, lying between the terminator and the limb, is almost exactly bisected by a succession of great wailed plains, — Petavius, Vendelinus and Langreuus, — all on the 60th meridian. This meridian in its sweep northward, traces out the western boundary of the Mare Fecuuditatis, cuts through the ring-plains, Webb and Apollonius, and bisects the Mare Crisium. In this latter Mare, we see the influence of these meridianal forces marked in still greater detail, since it is crossed by a number of ridges, — one of which is especially distinct on the photograph, — which streak it from north to south; a clear indication that llic tidal attraction of the cartii when the moon's crust was still in a plastic condition, was a chief agent in moulding the surface into its present shape. The Sea of Conflicts, from the beauty of its surround- ings and the strong relief into which it is thrown whilst the crescent moon is still young, has always been a favourite object of study. Its size too is convenient ; it can be examined as a whole, and the definiteuess of its outline makes it the more suitable for such study. In length, east and west, it reaches to 355 miles, whilst its * There will thus in 1012 be two total eclipses six months ajMrt, which is a very i-Jiv occurrence. 02 KNOWLEDGE [Makch 1,1901. length, iiorlh and soutb, is but 280. It is thus elliptical ill reality, as it is also in appearance, but its major axis, thi'ough the effect of foreshortening, shows as if it were the minor. The Mare Crisium was the subject of the Plate in Knowledge for March, 1899, two years ago ; but it was then shown under sunset illumination, whilst in tlie present Plate, the morning light is full upon it. The western border, therefore, was entirely lost in night in the former rejaresontation, and the eastern highlands were too strongly illuminated for their intricacies to be followed as clearly as they can be now. The magnificent rnountain group which forms the southern boundary of tlie Mare, can also be examined better under the present lighting; its broad deep bays and winding valleys being seen under the most favourable conditions. The western frontier is cjuite of a different character from the others, being a broad, gently sloping plateau; and the extension on the west of the Mare which begins under the shelter of the great southern promontory. Cape Agarum, and which appears on the photograph to be marked olf from the mam body of the Mare by a very distinct ridge, would seem probably to be a later development, an annexation after it had attained its original form of a nearly perfect hexagon. The centre of the Plate is occupied by the Sea of Plenty, which however is not shown here quite in its entirety. It covers an area of 160 thousand square miles, stretching some 640 miles front north to south, 410 from east to west. It narrows, however, greatly towards the south, being onl}' 130 miles wide where Yendelinus borders it, so that its shape as a whole is that of a pear. The photograph brings out in strong relief the successive ridges by which the plain rises from its lowest depth, — Ansganus U PeyrobS) Magethaens Maclaunn h/) Coiidorcel Hansen^ AlhazenV) yV^'^wn Sketch Mup. situated almost precisely at the centre of the Plate, — up to its western border, and which mark the stages of the subsidence of the crust. Immediately to the west of the Mare, is the beautiful walled plain of Langrenus, which in the completeness of the example which it offers of eruptive action may be considered the Copernicus of this region of the moon, and indeed it is not much inferior to the latter in perfect- ness of outline, whilst it considerably exceeds it in dimensions. The walls of Langrenus, however, do' not rival those of Copernicus in height, and its system of light streaks falls far short of that which crowns the beauty of the monarch of the Carpathians. The great walled plain at the top of the photograph is Petavius, nearly 80 miles in cliametci", surrounded by a lofty mountain wall, double on nearly every side but the north, where it is lower and broader. T^vo of the leading features of the formation come out on the photograph with especial distinctness; one the central peak, and the other the rill that leads from it in a south-easterly direction, right up to the wall of the plain. Between Petavius and Langrenus lies Yendelinus, a walled plain as extensive as its tw'o neighbours, but destitute of their sjinmctry and completeness, but for that very reason a more interesting region to study. Midway between Petavius and Veudelinus, but iurther from the limb, is Petavius B, a deep ring plain, standing in a bright elevated region. The brightness of this region renders it one of the most conspicuous markings in the Plate, and is an evidence of its relative newness. A very cursory glance at the limb of the Moon is sufficient to show that it is far from being a true curve, a very distinct flattening being very perceptible about the centre. This is of especial interest, inasmuch as it gives some suggestion of an answer to the question we so vainly ask, " What does the other side of the moon look like V It would seem that we have here another of the great grey plains which on the visible disk we call iiiaria. It is the Mare Smythii, and its presence justifies us in inferring that the unseen three-sevenths of the moon's spherical surface does not materially differ in general character from the four-sevenths we know. Like it, it would present, could we examine it, bright broken highlands and broad sombre plains, and every variety of lunar structure from the great walled i^lain to the smallest craterlet. - . - Hftttrs. [The Editors do not hold themselves responsible for the opinions or statements of correspondents.] THE PATH OF THE SUN. TO THE EDITORS OF KNOWLEDGE. Sirs, — In the notice of my work under the above title ill your January issue, an adverse opinion is expressed, and with your permission I desire to suggest a refei'euee to facts of such a character that they will either effectually destroy my theory of the Sun's course or establish its truth. Just as it is essential for the truth of precession that the south pole of the heavens should descril)e a similar circle to that of the north jiole, so is it requisite for the establishmeut of my case that the south ])ole should not move in a circle but remain in one spot ; and if proof of its motion can be furnished, I will admit tbe fallacy of my arguments. If, on the contrary, observations show that the south pole is a fixture, no other theory but mine can account for such a phenomenon ; nor can the doctrine of precession be maintained in face of a fact so coutradictory. I will only add that while abundance of evidence exists a.s to the present position ani revolution of the uorth KnoirUdiif. SOUTH NORTH SUNRISE ON THE SEA OF PLENTY. Fruiii a Photograph tak./u l?'J7. Man-ii 7tii, (ioli. i'an- Mfuii Tjim-, «itli thi- Great Kijuatorial CijimU- of the Paris Observatory-. Scale; — Diameter of Moon, ^2 irulies. Moon's Age, 4(i. 6' Hi. Mar.ii 1, 1901.] KNOWLEDGE. G3 jiilo, ;iU wo are tokl of the south pole is that it is iu a certain phiee. and I ilesire an answer to tlie question. Does it remain tliere? A\'.m. S.\npem.\n. 1-lth January, llH'l. [It is rather extraordinary that Mr. Saudenian, after havintr studied tliis sidijeet for so many years, and writing so loutidently upon it, should nevor have applied so simple a test to his theory himself. It is still more extraordinary that he should assume that astronomers who have been oliserviusr aevuratily the places of the southern stars for a eeutury and a half have not yet ascertained whether they showed the effects of prei'essiou or not. However.the answer is simple; the south pole of the heavens moves in exact accordance with the north pole. A pair of stars taken from the nei-jhbourhood of each pole will show this clearly. Nos. ti and 16'.M of Bradley's Cataloi>ne are iu II. A. oh. and 12h., and are distant from the north polo I'S" and 12° respectively. /3 Hydri and y Musca> have similar K.A "s, and are- distant from the south pole 12" and 18° respectively. Now if we compare Lacaille's Catalogue for 17o0 with "the Cape Catalogue for 1890; and Bradley's Catalogue reduced to 1 750, with the Eadcliffe Catalogue for 1890, we get the following apjjarent changes in the places of the stars due to the actual motion of the jjoles. K.A. 1750. K.A. 1S90. Dili. S.P.D. 17.W. S.P.D. 1800. Diff. h. la. 8. h. 111. s. in. s. o • " o ' " / " S HrJri II l'.; 120 il 19 KX +7 «■.". 11 20 12 12 7 :U +47 22 y MusciE 12 17 *)-6 12 25 54-2 +7 59(i 1!) 15 7 18 28 29 —46 38 E.A. 1750. R.A. 1S90 Difl. N.P.D. 1750 N.P.D. 1S90. Dill. h. m. s. b. lu, s. m. s. o . /< o / »< / ,/ Briiaie.v6 0 2 31-3 0 9 S9-(J +7 2S-3 14 2fi 23 13 .'59 38 —46 45 Bradley 1634 12 0 67 12 7 22 +6 55S 10 .i9 37 1148 21 +46 46 The figures show that the north pole has moved in the 14it years about 47' downward tow-ards Bradley 6, whilst the south pole has moved away from |3 Hydri on the same meridian, almost exactly the same distance. — The Reviewer.] SUNSET PHENOMENON. TO THE EDITORS OF KNOWLEDGE. SiR.s, — Before the raihs started here at the beginning of summer a strange phenomenon was occasionally observed at sunset. From a point in the east, exactly opposite where the sun was disappearing below the horizon, rays of light streamed out, extending a considerable distance. It looked just as though the sun had gone down in the wrong place, and when there were rays from both east and west the effect was very striking. Can you give me an explanation in one of the numbers of the paper ? P.O. Box 66, R. L. McDonald. Bulawavo, Rhodesia, fOth January, 1901. [The phenomenon is essentially of the same character as the familiar one which children call "the sun drinking," when, in somewhat hazy weather, the shadows of clouds stand out in the moisture-laden air. So, under certain circumstances, about a quarter of an hour after the sun has gone down, we may occasionally see similar shadows apparently radiating from the Sun's place. These are likewi.se the shadows of clouds thrown upon the air full of moisture or of dust. The beams are in reality parallel straight lines, but from the effect of perspective they seem to radiate from the sun's place, and to converge again to a point directly op|iosite to it. It is, however, rare for them to be traced entirely across the sky, and as the air overhead is necessarily freer from the minute particles which make the beam-! evident, they can very seldom be traced across the zenith, even when they are seen near their converging point in the east. — E. Waltkr Maunder.] Astronomical. — At the annual meeting of the lioyal Astronomical .^ociety (ui February 8tli, the Gold Medal of the Society was awarded to I'l-oC. K. 0. Pickering, the well- known able and energetic Director of the Observatory of Harvard (.'ollege. In the course of a letter ex[)ressing his appreciation of the honour. Prof Pickering made the interesting announcement that with an instrument of only 8 inches aperture, he is now able to photograph the s[>ectra of stars down to the ]'Mh magnitude. Professor W. W. Campbell, who is well known for his astrophysical researches, ha.s been appointed Director of the Lick Observafcoiy, in succession to the late Prof. J. E. Kceler. The oliservations made by the members of the Variable Star Section of the B. A. A. indicate that the observeil phases of Beta Lyra' fall a little later tlian the (tahnilated phases as published in the Cartie.s who observed the solar eclipse last May have i-ecently been issued by the Koyai and Koyal Astronomical Societies. They show that although perhaps no striking discoveries were made, a vast number of valuable records of the phenomena were secui-ed. Mr, Newall attaches some importance to the fact that the moon was darker than the sky. thus suggesting that some of the light usually attributed to the sky comes from beyond the moon. Mr. Evershed concludes that the " flash " spectrum is as constant a feature as the Frauuhofer sjiectrum itself. — A. F. Entomological. — Some interesting observations on the growth and development of instinct in sjiidi^rs have been recentlv publishi'd bv Miss A. B. Sargent {Proc. Acad. Nat. Sci., FhllaMpia, 1900, pp. ;j9.'')-4dl ). The species studied were a large orb-weaving sjnder Jrfjiope, and the common long-legged tube- weaving spider of North America, Afjelenn nacvia. (Our British A. lahyrinlhicu, is well-known to arachnologists.) Almostall mother sjiiders surroiindtheir eggs with a silken cocoon, iu which the young sjiend the first few weeks of their lives after hatching. Miss Sargent concludes that the main object of this cocoon is to jirevent evaporation of moisture from the young spiders, and that it serves in a less degree as a protection against enemies, such as wasps and ichneumon-flies. The young spiders were kept under observation through the winter, and it was found that they could endure a large amount- of cold and damp, but that warm dry surroundings killed them. When associated together in the cocoon the young Argiope were always found to rest with the ventral surface out- wards, perhaps to facilitate respiration by presenting the breathing holes to the outer air. In the development of the senses, touch si ems to be shown earliest, and light and darkness are distinguished before the form of objects can be made out. The earliest '• psychical " manifestations made by the young spiders were inter]ireted as indicating fear. While still iu their " little n(.'Sts," young spiders seem to live harmoniously together, but the individuals of an Agelena family were eager to eat one another when they had bsgun to make their own way iu the world.— G. H. C. G4. KNOWLEDGE. [MATicn 1, 1901. Zoological. — The micro-organism of distemper in the dog is described by Mr. M. C. Potter in the Proceed ingf! of the Koyal Society. It is shown tliat a cnltnre can readily be jiroduced, which tliere is good hope will lead to a very considerable mitigation of the disease in question. Por several years Herr G. Tornier has been studying examples of lizards, newts, and frogs with double tails or additional limbs, and has shown {ZooL Aiizelger, 1897-98) how such abnormalities can be produced artificiaUy. In his most recent contribution to the subject (Ihid., 1900, No. 614) he figures several newts showing various ty23es of bifid tail, and describes in detail the manner in which regeneration of the tail produces such abnormalities. Mr. Walter Rothschild's long-expected monograph of the cassowaries, together with Mr. W. P. P)'craft's dis- sertation on the structure and relationshijDs of the ostrich-like birds, has just been published in the Transact io7is of the Zoological Societj^, illustrated by no less than eighteen coloured plates. It is a magnificent piece of work, admirably carried out from first to last. Eight species of cassowaries, which naturally fall into three groups, are recognised, several of them being divi- sible into a larger or smaller number of local races. Morjihologists will, of course, be most interested in Mr. Pycraft's communication. lu his opinion, the Eatitfe (or, as he prefers to call them, Palreognathre) have divero-ed in several separate branches from iioiuts verv low down in the avian stem, which is continued up- wards to split up into the various groups of Carinatte (Ne(it;nathi3e). It is, however, difficult to realise how these birds became flightless comparatively so soon after the acquisition of wings by the class in general. And it is still less easy to understand how the Ratitte can be so much older than the cretaceous Carinates of the United States as the author considers to be the case. All the available palaeontological evidence (especially as Mr. Pycraft excludes the eocene Gastornis and Biatryma from the Ratite group) points exactly in the opposite direction. The attention of all interested in the molluscs and brachiopods of the British seas should be directed to- a classified list of species drawn up by a comnrittee of experts and published in the January number of the Journal of Ooiichologi/. The nomenclature appears to have been revised with great care, and it may be hoped that its publication will tend to promote uni- formity in this respect among conchologists. A most interesting exhibit is now on view in the Central Hall of the Natural History Museum. It consists of a wax model of the African tsetse fly, enlarged to the dimen- sions of a big bat. Alongside are models of red lilood- corpuscles, enlarged to the dimensions of medium-sized biscuits, and between them two models, on a similar scale, of the tsetse parasite. The whole exhibit is beautifully executed and most iustractive. According to the investigations of Miss Lee, of which an abstract appeal's in a recent issue of the Proceedinrja of the Royal Society, the skull-capacity of a large number of individuals does not tend to support the theory that relative brain-weight, cither in the individual ^ in the sex, is associated with relative intellectual power. It is stated that " one of the most distinguished of Continental anthropologists has less skull-capacity than 50 per cent, of the women students of Bedford College; one of our leading English anato- mists less than 2>5 per cent, of the same students." #otucg of ISoofeg. "By Land asi> Sky." By'the Rev. John M. Bacon, m.a., F.R.A.s. (Isbister i^ Co.) illustrated. 7s. 6d.— Mr. Bacon's book will probably be ,read more for its living interest and spirit of adventure than for its scientific ciualities. His narratives of balloon ascents by others and himself, and his descriptions of observations made under these and other conditions, possess the personal and general characteristics appreciated by a large ])ublic. We hasten to add that the book also contains many original observations on the transmission of sound, and revises some of the views on that subject usually found in text-books. Take, for instance, the belief that clouds can produce echoes. Mr. Bacon says that he has " never obtained an echo from a cloud, either from a hollow of such cloud, from the under surface of a cloud canopy, or from the upper surface of a cloud floor." No sky or cloud echoes were ob- served by him even under the most favourable conditions. Some remarkable observations in the whispering gallery of St. Paul's are described, and they seem to dispose of the theory that reflection from the opposite parts of the dome is the sole cause of the phenomenon exhibited by the gallery. The suggestion is made that the sound waves travel around the wall " as a ball hugs the circular end of a bagatelle board," but this analogue will not commend itself to the mind of a physicist. Incidentally, attention is called to the fact that instead of going to a window to listen to a distant sound, it is often better to open the case- ment .aud to retire back into the room. As to the action of fog upon sound, Mr. Bacon holds that though a uniform quiescent fog may offer no obstruction to sound, rolling masses of fog of varying temperature and density may impede sound waves, or even reflect them. In one of his essay.s, IMr. Bacon throws doubt on the statement that the sound of a bursting meteor has been heard on earth, and suggests that when such a report has been heard it probably had a terrestrial origin. We believe that no shooting-stars have ever been accompanied by explosive sounds, but surely there is ample e-vddence that actual meteorites and fireballs have been heard to explode. Mr. Bacon gives the impression that all meteor sounds are illusions. "Desion IX Nature's Story." By Dr. \V. Kidd. (Nisbet.) 3s. ('id. net. — In these days, when we hear so much of the evolu- tion of animal organs and structures according to an assumed " adaptation " to inanimate surroundings, and of the origin of horns and antlers from the bruises produced on their heads by contests between the males of the ox and deer tribe, it is distinctly refreshing to find that there is a writer left among us who has the courage to plead for the older conception of " design " in nature, and for the direct supervision of a personal Deity over the evolution of the animal life of our globe. 'V^^hether the author has succeeded or not in proving his contention, we may well leave our readers to judge for themselves, and we will therefore be content with quoting his concluding paragraphs. After referring to the fact that plants alone extract nutriment from the soil, and that animals live upon the present or p.ast life of plants, Dr. Kidd proceeds as follows : — " It were wearisome to elaborate this well-known fact of nature. The simple fact remains, and no scientific explanations of the ' natural ' laws under which it takes place touch for an instant its striking value as a broad argument for Design in Nature. . . . The objections of Darwin, Romanes, and Milnes IMarshall, by the very earnest- ness of the challenge, and the magnitude of the answer afi'orded by the whole vegetable kingdom, constitute a body of evidence against the blind mechanical force which they deify of obvious cogency," " A Year with Nature.'' By W. Percival Westell. (Drane.) Illustrated. 10s. Gd. — Under this title the author has perpetuated, between handsome covers, and in au expensive form, a series of oliservations of nature referable to each month of the year, and previously published in various journals. We can discover no permanent value, or imleed interest in these papers, neither is there anything original in them. Indeed, Mr. AVestell's observations are little more than a series of platitudes badly strung together, and it seems a )iity that they were not jillowed to remain in the comparative oblivion from which they have been dragged. As far as the author's qualifica- tions for writing are concerned we judge him by bis own words, for he has " not tried to cultivate any literary style," and in his opinion, the " rush and tear of present day life only allows us to sip, rather than drink, at nature's sweet fountain." March 1, 1901.] KNOWLEDGE. 65 •■ ^YllAT i# LiFK ? " By F. HoToudeu, f.i..?., etc. (Chiiiunau ^<- Hall. ^ Illustrated, lis. — No useful purpose would be served by a descriptive or critical notice of this book. The author has jieculiar ideas upon some physical and biological phenomena, and he announces established truths as if they wore original discoveries. AVe have not for some time seen a book to which the remark could be more appropriately applied that "What is new in it is not true, and what is true is not new." "The Stoi'.y of Xinktkkntii Cextcry Sciknce." By H. S. WiUiauis, m.d. (^Harper Bros.) Illustrated. 9s.— Dr. Williams is not omniscient, but ho has managed to survey the tield of modern science in a very creditable manner. .So far as we are aware, no other single volume exists in which such a bright and connected account of the scientific progress of a century is satisfactorily dealt w^itb in reasonable limits, and we are glad to give Dr. Williams credit for making this available. Practically every branch of natural knowledge is passed in review in separate chapters, and though the book has an American origin, there is little evidence of a more than natural tendency to attach undue importiince to work done on the other side of the Atlantic. The author appears to have exercised a , wise discretion in the selection of material, and to be able to weigh justly the value of the results obtained by various observers, and in ditferent countries. He has the eye for broad principles and suggestive generalisations essential for the preparation of a successful book of this kind. The last chapter, on •' Some Unsolved .Scientific Problems," is a view of questions in physics and biology in the light of the results described in earlier parts of the book, and it suitably terminates the story. From internal evidence we conclude that some parts of the book were not written very recentlj-, but we are content to let this pass. The titles of the reproductions of star clusters, on pages 71 and 81, need revision, and the picture of star spectra, on page 73. does not show a single spectrum line. The pictures of clouds are also not worthy of the text, that of stratus clouds being very bad. Notwithstanding these minor imperfections, the book is one to be purchased by everyone who desires to become acquainted with the main lines of scientific progress in the past century. ►-*-• BOOKS RECEIVED. Matnculalion Directory. Xo. XXIX. Jauuarv, 1901. (The Univeriitv Tutorial Series.) (Cambridgo : Burlington House.) Is. Sepori of the Hampsiead Scienlifc Society, 1899-19U0. :3d. Tie Pianist's ABC Primer and Gvid'e. By W. 11. Webbe. ( London : Fors_i-th Brothers.) 6s. net. yiichael Faraday : Six Life and Work. (The Century Science Series.) By Silvanus P. Thompson, D.sc, F.B.s. (Cassell.) 5s. Tramactionn of the Royal Scottish Arborictilfural Society. Vol. XVI.. Part II. (Edinburgh : Douglas & FouUs.) Debrett's Botite of Commons and the Judicial Bench, 1901. (Dean.) The Complete Works of John Keats. Vol. III. Edited by H. Buxton Forman. (Glasgow : Gowans i Gray.) Is. net. The Self-Educator in German. (Self-Educator Series.) Edited by John Adams. M.A.. B.sc. (Hodder & Stoughton.) 2s. 6d. Detchanel's Xafural Philosophy. Part III. — Electricity. By J. D. Everett. M.A.. b.c.l.. f.b.s. (Blackie.) Illusti'ated. 4s. 6d. The Self -Educator in Chemistry. (Self-Educator Series.) By James Kuight.it.A.,B.sc.,F.c.3., P.G.S.. F.B.l.s. (Hodder & Stoughton.) 2s. Gd. Museums Association. Report of the Proceedings, 1900. Edited by E. Howarth. F.R.A.S., F./i.B. (Dulau ) Advanced Exercises in Practical Physics. By Arthur Schuster, IH.D., r.B.S.. and Charles H. Lees, u.SC. (Cambridge : University Press. London : Clay.) Illustrated. An Introduction to Modern Scientific Chemistry. By Dr. Lassar-Cohn. (Grevel.) Illustrated. Zooloycal Besults during the Years 1S93, 1S96 and 1897. By Arthur Willey, D.sc.(loyD.), hon. m A.(cAyTAB.). Pait V. (Cam- bridge : University Press.) Illustrated. 21s. Return. 1900. County Council Scholarships. (Eyre & Spottiswoode.) Symons's Meteorological, Magazine. February, 190] . (Sitaiiford.) 4d. The Studio. Vol. 22, No. 95. February loth, 1901. Monthly. Is. Differential and Integral Calculus for Beginners. By Edwin Edser, A.B.c s., f.ph.s. (Xelson.) 2s. 6d. The Journal of the Society of Comparative Legislation. December, 190"^. Edited by .John Macdonell, C.B., Ll.D., and Edward Manson. (Murray.) 03. net. The Cambrian yatural Observer. Edited by Arthur Mee, f.b.a.s. February, 1901. (Annual subs., 23. 6d.) A Manual of Elementary Science. By R. A. Gregory, F.E.A.8., and A. T. Simmons, B.?c.(tovD.). (Slacmillan.) Illustrated. 3s. 6d. BRITPSR .^' OHNiTHOLOtilCAI^;- ■NOTES;:^ Conducted by Harry F. Witherby, f.z.s., m.b.o.u. The MirtRATio>r of tjik Soso Thrush. — Refon-infj to the note iu Knowledge for January, on the " ]\li!,'rations of the Song Thrush," I am able bj recent observation to confirm one statement made there, viz. : " In the winter (from October to February) we have a different kind of migration. These movements are entirely due to outbursts ■»f cold or bad weather." During the evening and night of January 8th one of these outbursts of cold weatlier took place, and the next morning tlie whole country here- aliout was covered with snow. During the morning, and lasting for about two hours, 1 witnessed the largest migra- tion of Thrushes that I have ever seen, and I called the attention of several to the most unusual sight. The stream of Thrushes was continuous but irregular, and it passed directly over the town iu the direction of the sea coast — about twenty miles distant. Some thousands of birds passed over, sometimes in single stragglers, and at others iu dense flocks of hundreds. — E. SiLLENcE.Romsey, February, 1901. Snowi/ Old in Co. Donegal {Irish Naturalist, February, 1901, p. 50).— Mr. Robert Patterson records tliat a female Snowy Owl (Nyctea scandiaca) was shot on December 15tli last by Mr. John Olphert's keeper, at Bally-Connell House, Falcaragh. The remains of a rabbit were in the bird's stomach. The Snowy Owl is a rare and uncertain visitor to Ireland. King-Eider in Co. Down (Irish Xaturalist, February, 1901, p. 5U). — Mr. Patterson also records tliat on Xovember 10th, 1897, a mature male King-Eider (Somateria spectabilisj was shot in the Foreland Bay, off Donaghadee, by Mr. Wm. H. Shaw. The King-Eider is a verv rare winter visitor to Ireland. We believe that this is the first adult male that has been recorded. A Young Cuckoo on Migration (Irish yaturalist, February, 1901, p. 50). — Mr. Richard M. Barrington's systematic investigations into the records made at his instigation by Irish lighthouse keepers of the birds which strike the lanterns, have produced many valuable and interesting results. The latest find he records liere. The leg and wing of a young Cuckoo have been sent to liim from the Skulmartin Lightship," Co. Uown. The bird was killed by striking the light on Xovember 26tli, 1900. Young Cuckoos sometimes remain here until October, and one was killed at the Tuskar Light, oti' tlie west of Ireland, on November 2nd, 188.3 ; but November 26th is an extra- ordinarily late date. It is probable that the bird was bred some- I where up iu the liigh north. I Grey Phalarope in Lincolnshire (The Naturalist, February, 1901, I p. 42). — Mr. J. Conway AValter records that a bird of this species I was shot near Kirtou-by-Boston on November 9th, 1900. The Grey I Phalarope is a rather irregular visitor to Great Britain, and when it docs visit us it is extremely rarely found on the east coast of England north of Norfolk. Long-eared Owls as Anglers (The Naturalist, February, 1900, p. 42). — Mr. Max Peacock describes a very interesting angling per- formance by Long-eared Owls which he witnessed some time ago in the pai-ish of Bottesford, Lincolnshire. A pair of these Owls had a nest in a fir-tree near a mill. In the evening when the water-wheel stopped the Owls began to lish. The bird.- in turn swooped do» u into the shallow water (some 2J inches deep), captured a fish — dace, some 3 to 5 inches in length— and tlew off with it to the nest tree. All contributions to the column, either in the way of notes or photoijraphs, should he forwarded to Harry F. Witherby, at 1, Eliot Place, Blackheath, Kent. 60 KNOWLEDGE [Maech 1, 1901. FINGER-PRINTS AS EVIDENCES OF PERSONAL IDENTITY. By E. Lydekker. In the gradual and imperceptible transition from child- hood to old age almost all parts of the human frame arc subject to a certain amount of alteration, either in form or in structure, so tliat it is matter of extreme difficulty to find any one feature by which an individual may be distinguished with absolute certainty from among all his fellow men. A remarkable exception to this tendency to change is, however, exhibited by the minute ridges and grooves on the balls of the fingers, which, as explained in the article on " Monkey Hand- Priuts," aic airanged in a number of minute concentric lines forming characteristic patterns. In all monkeys, with the excejjtion of some of the man-like apes, the patterns formed by these papillary ridges, as they are termed, are of a comparatively simple type. The patterns of monkev finger-tips are indeed arranged in simple flexures, which come under the denomination either of " loops " or " arches," according to the classifi- cation employed in the deciphering of human finger- prints. Such a ''loop" is shown in Fig. 1, which FiG. 1. — Impression of Middle Huiiian Finger, ilisplaying tlie looped arrangement of the iiapillary ridges. represents the impression of the middle finger of a human hand. In an "arch " the flexure is still simpler, and does not exhibit that marked inclination to one side or the other which forms such a characteristic feature in loops. In a large number of human fingers a still more complex type of flexure is observable in the ridges, which Fig. 2. — Impression of Fore, Middle, and King Fingers of a Eiglit Human Hand. assume a kind of vortex arrangement around a central nucleus. This type is denominated a " whorl," and is beautifully displayed in Fig. 2, which shows the prints made by the fore, middle, and ring fingers of a right human hand. Still more complicated patterns may be produced by the mingling of two whorls, or of a whorl and a loop, or a whoi'l and arch in the same finger; such types being designated as " composites." Whorls and composites being obvioiisly more complex than loops and arches, it is interesting to note that they are vmknown in ordinary monkeys; and the gradual inogressiou in complexity of pattern from these latter through the man-like apes to man himself is just what would have been expected to occur if the doctrine of evolution be true. It has not yet been ascertained whether the presence of arches and loops is more common in the finger-tips of the lower races of mankind, while whorls and composites are relatively more numerous among nations of higher cultivation, but it is possible that this may eventually prove to be the case. As the result of the examination of the finger-tip impressions of a very large number of Europeans and natives of India, it appears that about five per cent, come under the denomi- nation of arches, while sixty per cent, are loops, and thirty-five per cent, whorls and composites; the pro- portion of each varying considerably in the several digits. For the purposes of forming a classification of finger- prints, arches, being so few, may be reckoned as loops, while composites may be included in whorls, thus giving only two types to deal with. But before going further a few words are advisable as to the manner in which finger-prints are taken. The fingers are first pressed on a plate of tin which has been evenly and thinly coated with printing ink, and may be then pressed on suitable paper in such a manner as may be thought desirable, when, if due precautions to avoid smudging are taken, clear prints similar to the originals from which the accompanying figures were reproduced will be obtained. When the tips of the fingers are merely pressed on the paper without any other move- ment, the print is termed a plain one, as in Figs. 1 and 2 ; and it is manifest that when (as in the case of the latter) the impression of three or more figures is taken simultaneousl)^ it must be of this nature. But such a print displays only the central portion of the pattern of each finger ; and in order to obtain the pattern of a laiger area of the finger-tip recourse is had to another plan. To take a rolled impression, as it is called, one finger only is inked at a time, and when coated with ink is laid on the ))aper in such a position that the nail is in a vertical plane, after which it is rolled on the paper across the ball till the nail is again vertical. Two complete series of such rolled impressions are exhibited in Figs. A and B. It will be seen that they are taken in the natural order, commencing with the right hand, and passing from the thumb to the little finger ; and then repeating the process with the left hand, the impressions from which are placed below those of the corresponding digits of the right hand. Of course such impressions are always taken in the presence of a responsible officer ; but to prevent the possibility of fraud, " plain " impressions of the fore, middle, and ring fingers of each hand are taken at the same time on the same sheet as the " rolled " impression. As an additional precaution, the three fingers in question are thrust through a frame having three apertures before they are inked, and the impression is taken while they are thus fixed. The three plain impressions shown in Fig. 2 are those of the three central fingers of the right hand of the individual marked B (see figures), and they will be seen to correspond exactly with the middle portions of the rolled impres- sion. Such correspondence is quite sufficient to indicate that the rolled impressions have been taken in their proper sequence and belong to the same individual. For the purpose of identifying individuals by means of their rolled finger-joints, arranged in the foregoing order, Mabch 1, 1901. KNOWLEDGE. 67 Bight thumb. \ A.— Classification No. ^ ^ Kight iiuloi. \ Loft index. w RIGHT HAND. Right luidilli'. \ LEFT HAND. Left middle. / Riybl litllc \ Loft little. / B. — Classification No. 32 32 II. CM RIGHT HAND. ight thumb. Bight index. Bight middle Kight i-ing. Kight littl w w w w w Left thumb. w ,m Left inilex. w LEFT HAND. Left Jiiicldlr. w ■=§gi. Left little. w 'm. m an ingenious schonie has been invented by Mr. E. R. Henry, Chief Commissioner of Police in Bengal. Those impressions showing whorls (or composites) are marked with the letter VV. Loops, on tiie contrary, are indicated by oblique lines, sloping in the direction taken by the loop itself, When, for example, the palm oi the 68 KNOWLEDGE. [Mabch 1, 1901. right hand being on a table, the downward slope of the ridges forming the looj) is from the thumb towards the little finger, the slope is said to be ulnar, on account of running towards the ulna, or larger bone of the fore-arm. In the right hand of individual A (see figures) all the slopes are ulnar. When the loops in the right hand take the opposite direction, that is to say when they incline from the little finger towards the thumb, they arc said to be radial, on account of pointing towards the radius, or smaller bone of the fore-arm. It will be obvious that the direction of ulnar and radial slopes will be the reverse in the left hand of what it is in the right ; consequently all the loops in the left hand of individual A will likewise be ulnar. Hence the individual in question shows no radial loop at all. In the formula adopted for the division of finger-prints into primary groups, all loops, whatever their direction (as well as arches), are indicated by the letter L. The digits are then taken in pairs as follows, viz. ; — Right, tluimb. Eiglit middle. Right littk'. Kight index. Hight ring. Left thumb. Left iudex. Left riug. Lrft middle. ~ T:.eft little. And the letter L or W substituted for the names of the fingers themselves, according as their respective impres- sions show loops or whorls. Following this arrange- ment, the formula of the finger-prints made by individual A will be L L L W L, L 1, h h ~ V In individual B, on the contrary, the formula will be AV WW \V W W W w ■ W W Tlii.s, however, does not help much in making a workable scheme of classification, and the following plan has con- sequently been proposed. Whenever a whorl (W) occurs in the first of the five pairs, it is allowed to cx)unt as 16; if it occurs in the second pair its value is 8 ; if in the third pair 4, if in the fourth 2, and if in the fifth 1. Consequently the numerical value of individual A will be £_ — __£ -—"-.^ U ' 0 0 0 0 ~ 0' while that of individual B will work out as 10 8__4_£_1. 31 Itj " 8 ~" 4 ~ 2" "■ 1 " 31' To each value thus attaiued - is added, and the fraction* being inverted, what is known as the primary classification number is obtained. Accordingly, in individual A we have ^ -I- ^ = ^, and by inversion — - ; while in B we have 31 i _ ^ 31 + 1 ~ 32' It will be obvious that individual B presents the highest possible formula, every one of the digits exhibit- ing a whorl. Individual A, on the contrary, displays very nearly the lowest possible formiila, which would occur when there were loops in every digit, in which case .IX- 1 111" 1 1 the tormula would he -|- . = ,-• Consequently all possible combinations of loops and whorls may be indicated by formulse varying in value i 32 between a minimum of and a inaximum of ^■ 1 32 * Although, of course, not really a fraction, it; is sometimes con- venient to Kpeali of tlip value as sueli. But in the first pair of digits the number of combina- tions of loops and whorls that it is possible to have are four, that is to say we may have any one of the following four values, viz : ^, "7^, ^, or -— • And L \\ L W since (to paraphrase from Mr. Henry's book on finger- ]3rints) the same numLer of combinations occur in the second pair of digits, and as each of these may be combined with each and every arrangement obtain- ing in the first pair, the total number of possible com- binations in these two is sixteen. But the third pair of digits has likewise four possible arrangements, which, taken with those of the first and second pairs, raise the number to 64. By adding the combinations to tiie fourth pair, the number rises to 2256, and with the inclusion of the fifth pair to 1024, which is the square of 32. Consequently a square cabinet containing 32 tiers of 32 compartments each will suflice for the accommo- dation of all the groups into which finger-prints are divisible according to the primary classification. But it is obvious that there may be a very large number of individuals in whom the patterns on the 1 32 fingers are expressed by the formula -, or 7^-, ; and as a matter of fact the largest accumulations do occur in the case where there are either all loops (r) or all whorls (.-,^)- Consequently sub-divisions of these great groups are essential. And a secondary classification has been in- vented, depending, in the case of the lower values, on the occurrence of arches or in the direction of the loops in certain digits, or, in the case of the higher values, on the manner in which the individual lines are arranged in the whorls or composites. To enter in detail into this secondary classification would be quite out of place, and those who would study the subject seriously must consult Mr. Heruy's book. In the lower values attention is paid to the circum- stance whether the index fingers show an arch, a radial, or an ulnar loop, or, when they have a whorl, as to the arrangement of the central lines. In cases where whorls are absent, and the formula is consequently -, both index . 1 A fingers may show an arch, when the formula wiU be - , -, or a radial loop, when it will be -, :^, or an ulnar loop, 1 Ti, when it will be expressed as -, =. And there may, of 1 A course, be any combinations of these, such as j, ^. In the individual indicated as A, in the figure, whose primary formula is 7,, it will be seen that the right index has an o ulnar slope ; while in what are known as the deltas of the whorl in the left index, a certain line takes a course external to another, and is consequently_classed as outer, with the symbol 0. The full classification formula of individual A will therefore be -^ — ^, Turning to individual B, the characteristic delta-line in the right index is internal, while in the left index it is external or outer, this being indicated by tlie symbol ^. Again, in the right middle finger the distinctive delta-line is internal, while in the corresponding digit of the left hand it is median in position, this being expressed as =r^. Consequently the coiniilete classification number for in- dividual B will be g| - q',^-' It will thus be seen that by paying attention to minute liolnts, the larger aocnnuilations of sheets may bo broken Makch 1, 1901.] KNOWLEDGE. (!9 up into such a numlvr of uiiuov groups that there will lie little ditKoultv in assignir.ir to its proper serial position each new record that is added, or in idciitifviug duplicate impressions of the same individual. Wlicu the classifica- tion numbers of nuy two or uiore sheets agree, even as regarding the letters denoting the secondary characteristics, they may be differentiated by comparing together (with the aid of a lens) the prints of each individual tinger, where a number of minute but characteristic peculiarities ! will be sure to be detected, which will serve to distinguish the two records. The method of the ideutitication of individuals by means of this ingenious system is, of course, jierfectly simple. Where it is in use, as in India,, the finger-prints of every individual who is convicted in the law-courts are taken and duly pigeon-holed or filed, according to the classifica- tion descrilied above. When any indiviclual, previously unknown to the police ot" the district, is charged with an offence, his finger-prints are immediately taken and duly classified. Reference is then made to the corresponding group of classification-numbers in the cabinet or file, and if an absolutely identical impression is found, the whole history of the individual is at once made known. If the duplicate of his impression is not in the series, it is evident that the accused is " unknown to the police," and he is therefore entitled to the benefit of the " First Offenders' Act," or its Indian equivalent. But this is not all. Occasionally a burglar, ])y cutting his hand, or by smearing it with ink or some other substance, may leave the impression of one or more of his fingers on some article in the house. And Mr. Henry, in a paper read before the British Association at Dover in 1900 (to which we are indebted for the information embodied in this article), gives an instance of this nature which led to the identification and conviction of the criminal. Briefly stated, the case was as follows: — The manager of a tea estate in the Julparguri district was found foully murdered, his despatch box, in a rifled con- dition, lying near the body. In this box was an almanack marked with two faint brown smudges. By chemical examination these were proved to be made by human blood, while, by the aid of a magnifying glass, one of them was discovered to be the print of a human thumb, which was subsequently identified as that of a certain individual whose finger-record had been filed by the Bengal i)olice. The evidence was considered by a native jury sufficient to convict the accused of theft, although (somewhat inconsequentially) not of ratirder, and he was accordingly sentenced to a term of imprisonment. Other systems of classification of finger-prints have been prepared, but, in our opinion, none are equal iii simplicity and convenience to that invented by Mr. Henry. As already said, it has been adopted in India, and it might, we think, be advantageously used in this country. In addition to their value as a means whereby suspected persons may be readily and undisputably identified, finger- prints have, however, as already indicated, a vei-y con- siderable degree of interest to the naturalist. They serve to show that even in such minute details as the arrange- ment of the ridges on the skin of his finger-ti[is man has attained a higher degree of si>ecialisation than the lower monkeys, and that certain of the man-like apes alone approximate to him in this re.speet. The subject is, however, still in its infancy, and further interesting results will doubtless accrue from a more extended investigation line of the points to determine being, as already indicated, whether " whorls " are more predominant on the finger- tips of the higher as compared with the lower races of mankind. Conducted by M. I Crpss biUTir^ii \ KK.sL-s CoNTiNKNT.vi, IMiruoscopi;?. — For accurate original research, where the worker has some understandiug of the mechanical and optical means at his disposal, there is no microscope in the world to be compared with the best of those produced by tlic leading Rritisli houses. Iti them are to be found rofincnionts of michaiiical skill wliicb, suitably employed, call forth a response from objectives and condensers which causes them to yield their very best cllects. ICveii in the British models of medium size and at modest cost there arc to be found several that are but slightly less ofl'octive than the largest, and with which no Continental stand can vie. Yet the British microscope plays but an insignificant jiart, numerically, in the world's supply. In laboratories and lu places where microscopes are largely used, the Continental instrument holds sway and seems likely to maintain it, at any rate for the present. The question of price is not the factor in the existing state of things, for even in student's stands the Kritish manufacturer keeps his rates at the com|)etitive mark. Why then is it that he docs not receive a larger share of appreciation and supports The reasons usually given appear to be two in number, and are — 1. The British microscope exceeds the needs of the laboratory worker and student ; 2. The casing and general " fit up " is inferior. The first is distinctly a laboratory cry, and may be regarded as due to want of appreciation and education in matters micro- scoiiical. The second is more general in its ajiplication and in a lesser degree influential. To do the largest amount of work in the least possible time with the most cut and dried materials is a spirit which pervades the present day, and it applies to microscopical as much as to other spheres of activity. The laboratory worker wants as much done for him as jiossible. so that it may only be necessary for him to place his object on the stage and " spot '' the structure. To get the best from lenses and condenser is not in his province. "Numerical aperture," " aplanatic cone," and "critical image'' are, as a rule, vague terms to him. Hence it comes that an instrument that always has its auVjstage condenser approximately focussed and centred, and the mirror fixed in the line of the optical axis, eaves him time and bother and suits his methods of working. Xo one can defend the use of what are in reality but rough and ready means of examination of structure, and no reliance can be placed on deductions made from such methods. We are among these who are sanguine enough to hope that in the no very distant future, the advantage of perfect control in mariipulation, and a rigid tripod foot, as provided in the majority of British microscopes, will supersede the Continental model. This can only be brought about by a demand for more thorough teaching of microscopical principles and manipulation, and if good work is to be done in English laboratories it should be seen to that those who use the instruments shall get the best possible out of them. If this necessity were recognised and taken up vigorously by the scientific world — and many know full well how much it is needed — a different state of things would in time prevail. We would not advocate the pandering to a low degree of appreciation by reducing either the calibre or working accuracies of the instrument. Let us all do our best to raise the users to a higher level. Meanwhile, the British manufacturer has opportunities of making his instruments more acceptable in several ways, and especially in the casing and general " fit up." A great improvement has taken place in recent yeai-s, but there is yet room for further effort. (Jenerally speaking, I'ritish houses are inferior to their Continental rivoN in this 70 KNOWLEDGE [March 1, 1901. respect. It must be remembered that the horseshoe foot is more easily gripped and held tirmly in its case than the tripod, l)ut ;i strong and neat fitting for tlie latter ought not to be beyond the powers of the ingenious to contrive. It may be fearlessly stated that a good day is coming yet for British microscopes if the makers do but set their house in order, and in addition to providing the most sound and accurate instru- ment that can be, they give due consideration to every detail which will make them acceptable to those who are influenced by appearance. There is no disgrace in making a microscope and its case ornamental as well as useful. St.vininii Living BAfii.i.i. — We have had placed in our hands an interesting paper by Mons. A. Certes dealing with the selective colouring power of the spore-bearing filaments of the liriiui Sjiiritlxirillas giga^ with methylene blue, and the following is a brief ?vs!/«/c' of it. He remarks that the experiments of Brandt, Henneguy and himself, dating from 1881, jirove that living protoplasm can absorb certain aniline colours, but little has been done by biologists in the study of the action of colouring substances on living microbes. It has been found that certain microbes cease to live on being stained, others absorb the stain and still remain alive, while others do not absorb the stain either alive or dead. The difficulty of making observations on selective coloration is obvious on such delicate subjects as bacteria, but M. Certes was fortunate in discovering the SpirnlKirilhii' g/i/as in the reservoirs at Aden ; the length of these is usually 150 — 160 mikrons, but they are occasionally found 400 mikrons long. These organisms placed in a weak solution of methylene blue continue to move about with the same activity as before, and the stained specimens can be preserved alive until the following day if care be taken not to exclude oxygen. The effect of the stain varies according to the stage of development of the bacilli. During the first two or three days the living specimens are entirely and uniformly stained in blue exactly like dead specimens. When the period of sporulation commences, alongside of the totally stained bacilli, the presence of bacilli of different shapes is observed, partially stained and much more clearly. In the same specimens are coloured rings in juxtaposition to uncoloured rings, grouped in the most varied manner and without any apparent fixed rule. The spore-bearing individuals which appear a little after, give the clue to these selective coloration phenomena, which acquire a still greater clearness when the specimens are larger — as the turns of the spiral are less serrated, and the spore-bearing bacilli move more slowly in zig-zig fashion. One sees, therefore, that the spores, while refractive, have, except in rare cases, absorbed the colouring matter, and that the filaments which carry them are, in general, more feebly coloured, sometimes even uncoloured, and that in those specimens whose spores are localised at one extremity on a fixed point on the filament, the rings which carry the spores are almost always uncoloured. Success largely depends on the colouring re-agents that are used. The finest quality of Ehrlich's blue and the chemically pure methylene blue of Gri'ibler and IMchst in very weak solu- tion are recommended, and they should be used at the precise moment when the first sporule-bearing individuals appear. These phenomena are only visible in the living state ; dead specimens stain so rapidly and uniformly that it is extremely difficult to obtain preparations in which the differentiated coloration is distinctly visible. Xf.W ArP.\R.\TUS DKSCRiliEIl i!Y Manuf.\ctureks. — We have received from Messrs. A. E. Staley & Co., of 35, Alderman- bury, London, some very interesting notes regarding the microscopes and accessories manufactured by Tlic Jlau^th if- Lnwh (Ijilicii! r-.,, ItiH'hester, Ncn- Yuri:, U.S.A. It is, unfortunately, impossible to reproduce the details in their entiret3', but we have much pleasure in calling attention to the fact that Messrs. Staley have been appointed agents for Great Britain for these famous instruments. A perusal of the English edition of ^lessrs. Bauscb & Lomb's catalogue discloses the fact that prices have been considerably modified for the English market. Those who have a preference for the Continental type of stand will find an assortment of these of varying sizes, while microscopists who are interested in objectives and apparatus will find it well worth their while to peruse the handsome catalogue. The Bausch and Lomb microscopes have a great reputation in the United States, and are, undoubtedly, soundly constructed, well finished, and in the English catalogue moderately priced. ir. Watson i(- Sniix, 313, High IluJhoni. H'.^'. — A new form of sterilizable needle for blood examination, designed by Drs. Slater and Spitta. It is of metal throughout, can be sterilized, and remains so when carried in the pocket. It is .self-contained, and carries a reserve of lancet-pointed needles in its recessed end Notes and Queries. — Commuu/cations and enqxiiries cm J[/cro.scopical inatter.t are cordially invited, and shoidd he addressed to M. I. CROSS, Knowi-EDcf, Office, ,^2(i, Hicih Ilolhorn, W.C. NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. OiACOBlNl's Comet. — The small comet discovered at Nice, on December 20th, was very faint, and it had already passed its peri- helion. Becoming faint«r with increased distance from the earth it w.TS only observed in large telescopes, and has now practically passed beyond the range of risibility. From observations between December 2-tth, 1900, and January 14tli, IHOl, Prof. Krentz, of Kiel, finds that the comet revolves in an elliptic orbit, with a period of about 6'88 years, so that it belongs to the Jovian t^amily. It passed through perihelion on November 28th, 1900, and the elements of its orbit bear a resemblance to those of Wolf's comet of 188i. and Barnard's comet of 1892. The comet being a periodic one of interesting character, it is to be hoped that position-observations will be secured over a sufficiently long interval to enable a good definitive orbit to be derived from them. On JIarch 6th the place of tlie comet will be R.A. 4h. 7m. .53s., Deo. 10° 1' ,8., so that it will be near :Mii-,i Ceti. Bboesen's Comet. — Tliis object ought to be fairly well visible in March, but in view of the fact that its continued existence is some- what questionable, we cannot look forward with confidence to tlie re-appearance and discovery of the comet. First seen by Brorsen at Kiel on February 26th, 18-tS, it was found to be revolving in an elliptical orbit with a jieriod of about 5i years, and it was satis- factorily re. observed in 1857, 18G8, 1873, and 1879, but escaped notice at the last three returns in 1885, 1890, and 1896. Slioiild the comet elude detection during the present spring there will be no alternative but to conclude that, like the double comet of Biela, it must be num- bered with the lost comets. Hind pointed out in Ast. Nach., 3271, that the orbit of Brorsen's comet and of Denning's comet (T. 1891) intersect in long. 285, and that in April, 1881, the two objects must have been dose to one another near the point of intersection. He was led to the conjecture that Brorsen's comet, on its recession from perihelion after it was last observed in 1879. may have met with a catastrophe, bringing about its dieintegi'ation and causing one portion of it to return in tlie aspect and orbit of Denning's comet of 1891. Dr. Scliulhuf supported these conclusions, and pointed out {Ast. Nach,, 3276) that the point of intersection of the two orbits coincides with the place of i heir nearest approach to the planet Jupiter, Dr. Lamp has also examined this interesting question, and found that the two comets passed through the corresponding points of their orbits on January 17th and January 23rd, 1881, respectively. The least dis- tance between the two orbits was 199 radii of the earth, I'here is very little doubt therefore that a close conjunction of the two comets occurred early in 1881, but whether or not this indicates the actual disintegration of Brorsen's comet on that occasion is open to question. The approach of the two bodies may have been quite accidental. In any case, the re-dctection either of Brorsen's comet of 1846 or of Denning's comet of 1894 will be important, as affording materials for the further investigation of the idea of their conned ion. Datlight Fireball of Janitabt 6tii. — This object, which ajipcared in bright sunshine, 52 minutes after noon, was quite of an exceptional character. It was observed by several persons in Glasgow. " T. 11." says he was walking along Great Westei'n Road a few minutes before 1 p.m. when the meteor tlashed across the north- western sky. " L. D " describes the object as bursting like a ball of fire among the hedges near the Catholic cemetery as observed from Lambhill Road. Another writer noticed it from AVhiteinch Park, and states that its flight was in the direction from X.E. to W, It was not like an ordinary falling star, but resemliled a rocket with a long streaming tail. It apparently exploded on Scotstownliill. As seen from Rosneath the meteor appeared as a ball of fire with a tail. It darted between the trees in a westerly direction about 20 feet off the ground. At Crossmylcof it looked like a roi'kct flying in a north- westerly direction. It was of considerable size, the glowing mass forming the head being as large as a bowling ball with a fiery tail attached. .At Durisdeer, Dumfries, '' J, W. W." refers to the meteor as a large silver ball, with a long tail, appearing in a north-westerly direction. \i Craighat, Killearn, X.B., the object vanished 12" above MvRCH 1, 1901."' KNOWLEDGE. 71 W.X.W. horizon, nt'tor a patli of 20'-'' or '23'-^ in ii direction fmm X.W. Tlie patli was sliglitly ilosi-onding, tho altiUktf heiiij; iihout 5" loss at tlieond. The brilliancy of the object was ostininted three times that of Venus at her best, nnd the nucleus threw olT a crimson tail I'' in lenath. BeiEnt FiBEHAtls.— Brilliant ni.'ti-ors of this chiss have been reported on foUonins; dates : — H. M. Pcnshurst, Kent. , Ueaminster, I lorset, and London. Kdinburgh. Pnmfries and Edinburgh. Bristol. February T ... S l p.m.. Felixstowe. Llanclly. Further descriptions of the oliserved paths of these bodie* would be inti-resting. .Iantaet Metbobic Showbk. 1901-.— The prevalence of moonlight and cloudy weather ha> probably enabled the meteors of Jaiiuory 2-3 to elude observ.ation this year. Xothmg of them was seen at Bristol, and no re|>orts have been received of successful observations elsewhere. iniiarv 10 i 18 am. 13 . . 10 44 p.m. -'•1 , a 55 p m. 2s 9 22 p.m. :;!! i 30 a.m. )ruarv T .. s ■I p.m. 12 7 40 p.m. THE FACE OF THE SKY FOR MARCH. By A. Fowler, f.r.a.s. The Sun.-- On tho 1st tbe sun rises at (5.49 a.m., and sets at 5.37 p.m ; on the 31st he rises at 5.41 am , and sets at 6.28 p.m. Tho sun enters Aries, and Spring com- ineuces on tlie 21st at 7 a.m. Few sunspots are to be exj>ected. During this month the Zodiacal Light is favourably placed for observation in the western sky after sunset. The Mooif. — The moon will be full on the 5th at 8.4 .V.M., will enter List quarter on the 13th at l.(> p.m., will be new on tho 20th at 12.53 p.m., and will enter last quarter on tho 27th at 4.30 a.m. The following are among the more interesting oceultations which occur during the month : — a 7. 13 g g. s b a I) ii p.® .'•■a i."" . The phase is of course almost inappreciable, the illuminated part of the disc on the 15th being 0 970. .Jupiter can (mly be observed in the morning, rising about 4.5 A m. on the 1st, and 2.20 a.m on tlie 31st. His path is a short easteily one through Sagittarius, and tho meridian altitude in London is loss than 20 degrees. Saturn is also in Sagittarius, a little to the east of Jupiter. On the 1st the planet rises about 4.25 a..m., and on the 31st about 2.35 a.m. Cranus is in the most southerly jjart of Ojihiuchus, nearly 4 degrees to the north-west of h. and, like Ju])itor and Saturn, can only l)e observed in the nioinings. On the 1st he rises about 2 30 am., and on the 31st about 12.34 a.m. The plauot is in quadrature on tho 8tli, and stationary on the 22nd. Noptune may still be observed until after midnight. He is stationary on the 8th,anfP. 2. Q to Kt7cli. 1. . . . PxKt, 2. QxPch., etc. [There is, unfortunately, a second solution by 1. ... I! to Q6, threatening 2. Q to Kt7ch.] Correct Solutions of both problems received from W. de P. Crousaz, J. Baddeley, Alpha, B. Harlev, G- A. Forde (Capt.), F. J. Lea, G. Groom, C. F. P., C. C.'Massey, W. H. S. M., J. T. Blakemore, ((J), W. Nash, C. C. Pennington, N. L. Gillesjtie, S. G. Luckcock (6), E. Hunt, A. J. Head, Endirby, Vivien H. Macmeikan, J. Sowden, N. Buchanan, W. JaV (0), G. W. Middleton, Eugene Honrv, H. S. Brandreth, N K. Dutt, A. E. Whitehouso, F. A. Wilcock ((}), W. B. Alldritt, A. VV. Tyer, J. M. K., (J. Child, H. LeJeune, A. H Machell Cox, J. E Broadbeut, G. W. (ij), C. Johnston (6). H. Boyes, A. .Jackson, A. C. Challenger (R), A. Dod (6), W. 'Smith, C. S. Hudson, S. W Billings (0), F. Dennis All the above score 5, except where otherwise stated. Of No. 1 only from H. W. Elcuni. Of No. 2 from J. A. Ni civil son. For the first tinio ])robably in many years no iiicorri'ct gnlution to either prolilom lias been received. W.Jay. — See reply to "Endirby" below. A solution in less than the stipulated number of moves would count as an ordinary " cook." One other key, if there be one, should 1)0 sent with it. f. A. Wilrock. — A very successful (irst ap])earanco Endirhy. — Nothing can be gained l)y .sending more than two keys to any ])roblem. W. Nash. -Yes, your card gives 1. QQB3. 1 mmli regret your slip. 72 KNOWLEDGE. [Maech 1, 1901. /. BaddeJey. — Prohably uot ; but if such a course should be deemed advisable, a suitable warning vrill be given. E. Hunt. — Problems with more than one key mav possibly be given intentionally in the later stages of the competition. S. W. Billhtijs. — It is not necessary to give more than two keys to any problem, or to say which is the author's Intention. C. S. Hudson. — You will see that your suspicious are correct. Considering the reputation of the composer it is strange that these susj>icions were not shared by the large number of other solvers who gave B to Q6 only. S. S. — Too late to reply to last month. You will sne that yom- solutions were incorrect. W. F. P. — Solution of No. 1 correct, but Croydon post- mark was February 11th. P. G. L. F. — Many thanks. They will appear next month. a. J. Pearce. — Your communications have been handed to me. That which is remotely connected with Chess is noticed below. Please excuse my abstract of your jjaper. A table of the leading scores in the Solution Tourney will be given next month. Meanwhile some apology is due for the following attempts to atone for lack of difficulty by means of additional- quantity. PEOBLEMS. By C. D. Locock. No. 1. Black (8). ^«^^^ ^''^'■'/ '/ ^^^' WMi W White (9). White mates in two moves. No. 2. Black (7), »^_.,.,feSI^ » A wm^^,^,^/i,„^„,, BBS! 11:1 Wbiti (15). "S^Tiitfi mates in two moves. No. 3. BlACK (10). White (10) White mates in two moves. CHESS INTELLIGENCE. An Old Chess-Board Puzzle. Probably most chess-players are acquainted with the device by means of which a chess diagram may be cut into four pieces and fitted together in such a manner as to form a rectangle of apparently 65 scjuares. The method is as follows : Cut oft' the 24 top squares of a diagram, and cut that piece into two halves diagonally, from corner to corner. Then cut the larger piece of 40 squares along a line drawn from the left hand bottom corner of Qscp to the right-hand toji corner of K5. By fitting these pieces together, a rectangle, apparently lo x ."i, mav be obtained. Mr. R. J. Pearce, of Auckland, New Zealand, sends a mathematical exposure of the fallacy. I have not space for his piroof, and am doubtful whether it would lie intelligible to all the readers of this column; but the gist of the matter lies in the fact that while the " fitting " along the lines CD and EFis quite correct, the "fitting" along AB is by no means so accurate. In fact AB, so far from being a straight line, is in reality an attenuated rhomboid, ACBF, having an area exactly e([ual to that of one square of the chessboard. That is, the complete figure is composed of diagram paper amounting in all to Flowering Plants, with Illustrations from British Wild-Flowers. — II. Concerning Leaves. By R. LtoTD Prabqeb, b.a. rilliLtti-ttted) 79 Notes 82 Where Four Mountain Ranges Meet By i:. Walter MirSDKB, F.R.A.S. (Ill vstrated ) ... ... ... 84 Where Four Mountain Ranges Meet. [Piute.) Constellation Studies. — IV. Bootes and Hercules. By E. Walter JlArxDER, t.r.a.s. {Illu.ilratedj ... ..". 85 Notices of Books 87 Books Received ... 88 Letters : SrxsEi Phekomekon. By E. E. Markwick (C'ul.) ... 88 " Mks. Qcickly'sTablb of Green Fields." By H. Alc.ar andJoHN Jambs Coultox .S8 A CrRiois EiBCTROGBAPH {Illustrated). By William GODDBN- 89 Tub Xebulab Htpothesis. By H. Chbistoimier. Note by E. Walter Maunder 89 Is Hr.MAS Life Possible ox Other Planets!- By E. Llotd Jones. Xote by E. Waltee Macnder . . 90 HrMAN Finger-Prints. By AV. H. S. Monck PO British Ornithological Notes. CoTKluctetl by Habrt F. WiTHERIlV, F.Z.S., M.n.o.r. ... ... ... ... ... 90 Pre-Historic Man in the Central Mediterranean, liy John If. Cooke, f.l.?., f.g s., etc. . . 91 Microscopy. Conducted by 51. 1. Cboss 93 Notes on Comets and Meteors. By W. F. Denning, F.B.A.S 94- The Face of the Sky for April. By A. Fowler, f.e.a.s. ... 95 Chess Column. By C. D. Locoes, b.a 95 THE NEW STAR IN PERSEUS. By A. Fowler, f.r.a.s. On the early morning of February 22nd, Dr. Anderson, of Edinburgh, observed a star of magnitude 2.7 in the Milky Way in the constellation Perseus, in a region where no star had been jireviously know-n to exist. Another " new star " — to be henceforth known as Nova Per.sei, in accordance with the usual custom — had, there- fore, appeared in the heavens, and, thanks to Dr. Ander- son's speedy transmission of the news to the Hoyal Obser\'atory at Edinburgh, the whole astronomical world was soon actively interested in the new arrival. At the time of discovery the star already surpassed in brightness all the novse that had been observed since 1866, and the fact that on the evening of the 22nd it had reached the first magnitude encouraged the hope that it might even rival the famous new stars of 1572 and CASSIOPEIA Wfi 'NOVA PERSEI' Ftb 28''' IJOI !_1jj m :^^ PERSEUS .4»it. AURIGA-^J^ %• «»/3Ai|.i 13 WM :;.:"- /5 ■ • t- ^ •♦PleiaHes TAURUS FlO. I.— Chart shon-lnii position of Nova Pcrsci. has appeared for iieaily three centuries, and is almost the onl}' one during this period which has been ccrt.iiniy observed before attaining its greatest brilliancy. One of the first questions which naturally arises is .how long was the star bright before its discovery? The wonderful photographic " star traps " organised by Prof. Pickering at Harvard and Arecjuipa, by which all the principal stars visible every fine night are duly regis- tered, give a very definite answer to this question. The Harvard plates taken on the 19th of February gave no indications of any star as bright as the 11 th magni- tude in the place now occupied by Nova Persei, so that at that time there was certainly no star of a ten-thou- sandth part of the luminosity of that which was seen three days later. It is, of course, impossible to say what the actual brightness was before this amazingly sudden and tremendous outburst of energy took place, and equally impossible to believe that there was no body at all in that part of space prior to the conflagration. During the early stages of visibility of the new star the weather in this country was by no means favourable, and many who wished to carry on investigations hatl to be contented with occasional glimpses. A few such glimpses at Kensington on the night of the 22nd showed that the star was of at least first magnitude, but no photographs could be taken there before the 2.5th. At Edinburgh, however. Dr. Copeland and his assistants 74 KNOWLEDGE. [April 1, 1901. were a little more fortunate, and noted that on the 22nd, at 6.58. G.M.T., the star was about 0.3 mag. brighter than a. Tauri, and at 8.10 p.m. equal to Procyou, while on the 23rd, at 8.10 p.m., the nova exceeded Capella by 0.2 mag. On the 25th, observations at 6.30 p.m. at Kensington showed the nova to be intermediate between Aldebaran and Capella, but by midnight the star had perceptibly dimmed. By the 28th of February, the star had dwindled to about 2nd magnitude. Observations made by Colonel Maikwick and others also indicate that the greatest brightness, near magnitude — 0.3, was reached about the 23rd of February. Continued observations of the brightness of the star will be of great interest, and to those making estimates the following list of the magnitudes (Oxford Photometry) of the stars shown in Fig. 2 may be useful : — Name. Mag. Name. Maft. Nivme. Mag- Capella -OOS T Persei . . 407 X Persei 439 a. Persei . 1-93 K 4-08 0 4-40 B .. 2 40 >; .. 413 <\> „ .. 4-48 '/ „ 306 f* ., 417 16 „ 4-77 4 .■^09 p " 4-24 ■K 4-89 J „ . . 311 e ,. , 4-26 CO ,, 4-94 c 313 48 „ 4-30 30 „ 5-55 V „ 4 06 1 ,, 4-30 4'$ „ .■506 The latest observation to which reference can be made in the present article was made on March 12, when the magnitude of the nova was estimated to be about 4.0. The colour of the new star has also been changing. At the time of discovery. Dr. Anderson considered it to be bluish white, but a gradually increasing redness appears to have set in about the 25tli of February, and by March 2nd the star was distinctly of a red tinge to the naked eye. It is undoubtedly to the spectroscopic observations that we must look for the greatest additions to our knowledge of these strange outbursts, and it is satis- factory to know that excellent records of the spectrum have been secured. The earliest of these observations was made on February 22nd by Dr. Copeland, who found that the spectrum was then a continuous one crossed by a few dark lines, and described it as of a feebly developed solar type. At Harvard the spectrum was photographed on the 22nd, a few hours after Dr. Copeland's observations, and it was stated that the negatives showed 25 dark lines, six of them with bright lines on their less refrangible sides, and one with a bright line on the violet side. In a communication to the Royal Society on February the twenty-eighth. Sir Norman Lockyer stated that 10 photographs had been obtained at Kensington on February 25th, and it was remarked that the spec- trum of the latest nova was strikingly similar to that of Nova Auriga? (1892). Brilliant lines of hydro- gen at C and F, three strong bright lines in the green, and one in the yellow, each accompanied by a dark line on the violet side were obvious in a glance at the spectrum. The photographs showed similar pairs of dark and bright lines in other members of the hydrogen series, as well as in the K line of calcium, in addition to numerous other dark and bright bands. All the lines were very wide, and the separation of the bright and dark adjacent lines indicated a relative velocity of the two light sources of at least 700 miles per second, assuming that the displacement of the dark lines was due to motion in the line of sight. Some of the bright lines were apparently reversed — that is, there was a dark line down their centres. The velocities of the two light sources indicated by the spectrum were determined by photographing the spectrum of y Orionis side by side with that of the nova ; this disclosed the fact that the bright line source, apart from internal movements, was almost at rest with regard to the earth, while that giving dark lines was approaching the earth with the tremendous velocity already stated. The spectrum is by no means easy to unravel, owing to the great breadth of the lines, both bright and dark. Spaces between bright lines may easily be mistaken for dark bands, and vice verso. Never- theless, starting with the supposition that as some of the lines are not unfamiliar, most of them may be met with in other stars, it seems possible that the true dark lines may be discriminated by a process of matching with stellar spectra. In this way Sir Norman Lockyer has concluded that the dark line spectrum of Feb- ruary 25th was very similar to that which the spectrum of a Cygni would assume if all its lines were to become greatly distended through violent internal motions or other causes. If this be a correct interpretation, the spectrum then consisted largely of the enhanced lines* of various metals, and a temperature considerably greater than that of the sun or Sirius was indicated at this stage in the history of the new star. The relation between the spectrum of Nova Aurigfe and that of the solar chromo- sphere to which attention was drawn by A^ogel and others thijs appears to have depended upon the presence of enhanced lines in" each. In another communication to the Royal Society on March the seventh, Sir Norman Lockyer gave an account of photographs taken on February 28, and March 1, 3, and 5, from which it ai^pears that considerable changes in the spectrum were taking place. The con- tinuous spectrum and bright lines other than those of hydrogen were rapidly fading; the bright hydrogen lines became very complex and were possibly quad- ruple ; and some of the dark lines were dying out while new ones appeared. Careful examination of the photographs left little doubt that the principal bright lines in the green, near wave lengths 4924, 5018, and 5169, and a less bright one at 5317, were due to iron vapour at a very high temperature, while many others in the more refrangible parts of the spectrum also corre- sponded with high temperature metallic lines. Helium lines appeared to be absent, and the line in the yelJow was probably D and not 1)^. During this period a great part of the light of the star was due to glowing hydrogen, and the star was, therefore, red for the same reason that many of the solar prominences are red. Excellent photographs of the sipectrum have also been obtained by Father Sidgreaves, Mr. Newall, and Dr. McClean; these exhibit the features described above, and Dr. McClean finds many coincidences between lines of the nova and those of Sirius, as would be ex- pected, since the latter include numerous enhanced lines. M. Deslandres has also given a good account of the photographic spectrum (Coniptex Rendiix, March 4). A further description of the photograph taken at Harvard on the 22nd of February, and details of others obtained on the 23rd, 24th, and 25th. have been received * Enhanced lines are -those which are brightened in the spark spectrum as compared witli the arc spectrum, and since these lines occur without the arc lines in the spectra of some stars, whicli there is reason to believe to be at a very high temperature, they are regarded by Sir Norman Lockyer as indicative of high temperature when they are met with in other spectrii. April 1, 1901." KNOWLEDGE. 75 from Prof. Pickering {Harvard Circular^ No. 56). It is extremely fortunate that tlio spectrum was photographed both before and at inaxiinum brilliancy. At. these stages in the history of the star. Prof. Pickering finds the spectrum to have been distinctly of the Orion type, with a few bright lines, chiefly on the red sides of dark ones. Bv the ■J4th, however, the spectrum had undergone a most exlriuirdinan* change, and then resembled the well-known spectrum of Xova Aurigie, as it did on the 25tb when photographed at Kensington. The full signi- ficance of this transformation is not yet dear, but it was evidently a most important event in the development of the new star. The tinal stage, if Xova Persei behaves like Nova Cygni. Xova Aui'iga>. and others, which it resenibled soon after discoverv. will be that of a planetary nebula. •n 7 r« .r / X . -4^ > "^ '' ^c. .^^•4 \ -— / NOVA •/< • — — © 30\ C APCLL A ^--^ . "■" __---^ CO c e/c £0--^ p \ \ ^ Fio. 2.— Persons. It may be worth while to add that up to March 3rd the principal features of the beautiful spectrum of Nova Persei were observable with a McCIean spectroscope in use with a two or three inch telescope. This form of spectroscope is almost as easy to manipulate as an ordinary eyepiece, and is especially useful when it is not intended to take measurements of the lines. Numerous theories have been advanced to account for .such outbursts as' that of Nova Persei, but judgment on them should perhaps be suspended until the present nova has been more completely studied. Still, a few remarks on this question may not be out of place. Attempts to explain a new star as the result of some action taking place in a single body have not been considered success- ful, chiefly on account of the diiBculty of explaining the nebular state which most of them finally assume, and the collision theory in one form or another appears to be of much more general application. On Sir Norman Lockyer's hypothesis, the fact that a nebula remains is taken as an indication that a nebula — previously unrecorded — was there to begin with, and the outburst is attributed to the passage of a dense swarm of meteorites with great velocity through the sparser swarm composing the nebula; the denser swarm, on this view, is responsible for the dark line spectrum and the sparser one for the bright lines. Mr. Monck, in 1885, compared the action to that which takes place in a shooting star, and suggested that "now stars aro dark (or faintly luminous) bodies which acquire a short- lived brilliancy by rushing through some of the gaseous masses which exist in space " : a somewh.at similar view has been adopted and extended by Prof. Sceligcr. Many of the phenomena seem to bo explained on either of these suppositions, but collections of small bodies appear to be most consistent with the rapid cooling which takes place. In either case, the original nebula or " cosmic cloud'' might be expected to shine more brightly after the collision than before, in consequence of the disturb- ance to which it has been subjected. The fact that gaseous nebulse, like the new stars, occur in greatest abundance in the neighbourhood of the Milky Way strengthens the collision theory, and it may be noted, too, that on account of their greater dimensions nebulae ai'e much more likely than stars to be struck by wandering bodies. It may be remarked that there is another possible explanation of the pairs of bright and dark lines which are found in the spectra of new stars, besides that which refers them to two bodies having a great relative velocity in the line of sight. The lines in certain spectra are displaced slightly when the vapours producing them are under pressure, and Prof. Wilsing has found that in spark discharges through liquids, pairs of lines some- what resembling those of new stars appear in the spectrum. The evidence on this point, however, is incomplete. As the great brightness of Nova Persei allowed of the application of powerful spectroscopes, it may bo expected that a complete study of the spectra which have been observed and photographed will throw additional light on the origin of such celestial outbursts, and doubtless also on various other questions relating to the progress of events in stellar evolution. It is satisfactory to know that the new star was seen independently by several observers, though Dr. Anderson appears to have been the first in point of time, and it was through him that the news was at once circulated. This, it wHl be remembered, is the second discovery of the kind with which Dr. Anderson's diligence has been rewarded, the previous one being that of Nova Aurigae in 1892. THE WHITE NILE-FROM KHARTOUM TO KAWA. AN ORNITHOLOGISTS EXPERIENCES IN THE SOUDAN. By Harry F. Witherby, f.z.s., m.b.o.u. I._THE DESERT RAILWAY, KHARTOUM, AND OMDURMAN. Shortly after the battle of Om Debreikat and the death of the Khalifa Abdullahi, I found that it would be possible to travel in the Soudan. For fifteen years the country had been in the hands of powerful savage tribes, and before that time English naturalists, and espe9ially ornithologists, had greatly neglected the Soudan, although some Germans, as for instance Brehm, Hcuglin, and von Miiller, h;Kl done excellent work there. The country being thus more or less new ground to English ornithologists, I was the more anxious to visit it, and study the birds of a small portion at all events of what had become English territory, at least by right of conquest. ro KNOWLEDGE [Ai'BiL 1, 1901. So on the last day of February, 1900, I set out from England, joining at Marseilles Messrs. E. H. Saunders and C. F. Cambtirn, two taxidermists who were to accompany me, and we reached Cairo on March 6th. The journey from Cairo to Wady Haifa, even under the new conditions created bj' the railway, is to-day so well known that it requires but a brief description. Instead of a long journey by boat up the Nile one can now travel from Cairo to Assouan in about 22 hours in a train, which for ease and luxury would not shame any European railway. Notwithstanding the lowness of the Nile at the time of our visit, th.e country from Cairo to Luxor was green and luxuriant. Camels, cattle, sheep aud goats abounded, and evervwhere the half- naked people of many shades of chocolate, browu, and black were working on the land. Beyond Luxor the area of cultivated land grew gradually less. Wells, sakiehs, and shadoofs were not so frecjuent, villages were passed at longer intervals, and the inhabitants and theii- cattle became more rare in the landscape. At Assouan we found every comfort. From this point to Omdurman wo travelled under the joint Government of the Queen and Khedive. From Assouan a short piece of line took us to Shellal, above the first cataract, and there just opposite the Temple of Philae we embarked upon a steamer, for no railway yet connects Assouan and Wady Haifa. And here the character of the country completely altered. The day before we had travelled through a flat fertile land, whilst now we were steaming up the great river through a wild and desolate country of bare rocky hills, and having the merest strip of culti- vated land by the edge of the river. Here and there, however, where flat ground was avail- able between the river bank and the foot of the hills, as for instance at Korosko, cultivation was carried on. But this w-as onl}' possible with the aid of an elaborate, although primitive, system of irrigation. The sakieh, an endless chain of pitchers, somewhat in the form of a water-wheel, turned by oxen, and the shadoof, a bucket at the end of a long lever balanced by a lump of mud ■ and worked by men, were emploj'ed in raising the water from the river above the high bank. Often two sakiehs, or four or five shadoofs one above another, or a com- bination of sakiehs and shadoofs, were necessary to lift the water, so low was the river and so high was the bank. Of birds there were few in this reach of the river, but we noticed particularly that the hooded or grey crows* sp common north of Assouan, were no longer to be seen, their place being taken by a crow of pure black and white,t which was to be found as far south as we after- wards travelled. The scenery was bold and impressive, and the colour- ing exceedingly beautiful. The blue-grey river, edged with a strip of bright green crops, and here and thei-e a patch of dazzling white sand, led one's eye away above the bank where the desert seemed to have over- flowed, and ])oured forth between the rocks great streams of sand of a deep rich orange colour. A background of pinkish hills, and the pure blue sky above, completed a scheme of colouring difficult to surpass. One night by the light of a brilliant moon all these colours were to be clearly distinguished, even to the pink of the distant rocks and the blvie of the sky, but of such delicacy was the colouring that the whole scene became etherealised. Our progress by the river was slow and laboured. Owing to the shallowness of the water, it being the midst * Corn's coriv.r, Linn. + Comix xiriptilafiit. Dniid, of one of the driest of dry seasons, the steamer grounded and stuck continually, notwithstanding its flat bottom and shallow draught. By dint of much twisting and turning and a vast amount of hard labour on the part of our crew in poling and hauling, as well as in lightening the boat, we were not called upon to wait until the Nile rose before reaching oiu- destination. Judging by their constant and hearty calls for aid from above, one could well believe that the crew ascribed this good fortune to the will of Allah and his Prophet rather than to their own exertions. So we jDassed rocky Korosko, Ibrim perched on the top of a high and precipitous clifl', the wonderful rock temple Abu Simbel, and in four days from Assouan arrived at Wady Haifa. Once a miserable vdlage, Haifa now boasts of great workshops fitted with all the necessary machinery and appliances to keep in repair, and even to manufacture. i>J^>U^ r.r-4!^4-^ A Siikieli. everything connected with a railway, and the new town has been appropriately termed a miniature Ci'ewe. From Haifa the wonderful railway which bridges 230 miles of waterless desert originated, and from Haifa to an ever increasing distance each day, with marvellous regularity during its construction, ran two ti'ains with construction materials, and water and food for the great army of v.'orkers at railhead. In eleven months from its com- mencement all difficulties, and there were many, were overcome, and a railway which the best authorities had dubbed as the idea of a lunatic was com- pleted. The journey from Haifa to Abu Hamed formerly occupied some ten days. It is now possible by this " short cut " across the desert to accomplish it iii about as many hours. Of coiu-se this railway, both as regards permanent way and rolling stock, has vastly improved since the days of the expedition which culmi- nated in the battle of Kerreri and the capture of Omdurman, and it has been extended from the Atbara, its former southern terminus, to the banks of the Blue Nile opposite Khartoum. We travelled up in the last so-called tourist train of the season. This train was put together at Haifa, and many of its fittings wei'e made there. It was some- what devoid of cushions and elaborate fittings, which April 1, 1901.] KNOWLEDGE. 77 was only right iu so dusty a coi^itiy. But as far as comfort went one could wish for iiotliiug better. Every necessity was on the train, cars for sleeping in, cars for dining in. cars for snioiiing in, an excellent ctiixiiii', and even bath rooms. Wc stopped for every meal on account of the jolting of the train. At first the dust was rather a trial, but the quantity of it depends much upon the positiou in the train which one occupies, and also upon the direction of the wind. And after all one soon gets accustomed to eating, drinking, and wearing dust. On our journey up we accomplished the distance of o76 miles from Haifa to Ilallaya on the Blue Nile, including all stoppages, in 34 hours. But on the journey down iu an ordinary train, which did not stop for meals, we did the distance iu-li9 hours. During part of this time wo ran at the rate of 40 miles an hour with an excellent American engine, one of two engines which had to be obtained from America, because at the time they were urgently required. British engineers were fully employed in a strike and could not attend to such business as building railway engines. From Haifa to Abu Hamed the railway runs across a bare desert far from the river, which here takes a great eweej). Sand, flat and monotonous, as far as the eye can reach, stretches out on every side. Here and there a stunted mimosa bush or a black rock rising conspicuously from the sand serves but to accentuate the loneliness and barrenness of the scene, while the mirage on every side tantalizes the eye with its shmiug dazzling mockery. At intervals along the single narrow track are " stations," so called, but otherwise they are nameless being only numbered one to nine. Each of these boasts of one or two tents, and some tanks of water. At some are stores of coal, and at two there are pumps, which bring up from deep below the sand that priceless water which, with ■' Kitchener's luck,'' was happed upon during the con- struction of the railway, when water was so valuable for men and engines that a whole month was gained by these finds. At several of these stations w-o saw ravens, J and at one, kites. § What induces these birds to live in such forsaken spots, and upon what they feed, unless The River Bank, Oindiinnan, it is on just the scraps they can pick up round the tents, and how they get water to drink, are puzzles difficult to solve. At Abu Hamed, with its small white-washed station house, the river was reached again, and here a few scraggy doiu palms, the hard round fruit of which is nicknamed Dervish bread, are a delight to the weary eye. From this point onwards the country is less unintercsling. Mimosa scrub and stunted acacia trees struggle for an existence in the gritty sand, dark rocky hills rise in the distance, and a gi'oup of gazelles or a Hock of small birds may now and again be seen, Wc passed many a place made famous by coiiilict — • Berbei', the Atbara with its fine bridge, Shcndy opposite Metemma — and at length arrived at the railways unpretending southern terminus, Ilalfaya, a collection of a few huts upon the sand on the north side of the Blue Nile almost opposite Khartoum. Here we were greeted by a dust storm, which is no unusual thing at Ilalfaya, a fact which has given the place a nickname of much the same sound but of a deeper significance. After con- siderable delay we embarked on a steamer — a dahabeah — which was to take us over to Omdurman, and upon which we were to live during our brief sojourn there. X Corvus uiiihrinus, Suiidev. § Milvufi aegyptius^ Gjii. The " Bazaur " at Khartouin. Steaming down the Blue Nile towards Omduriuau we had a good view of Khartoum, which is built along the southern bank of the river amidst a grove of palm trees. It will be remembered that Khartoum was deserted, and converted into little less than a heap of ruins by the Mahdi, who set up his capital at Omdurman, a mere village at the time of the fall of Khartoum. We are now reverting to the old order of things, and although at present nearly all the business both official and private is transacted at Omdurman, yet Khartoum will soon become again the chief town and centre of the Soudan. At the time of our visit few buildings in Khartoum were completed, but along the bank of the river houses and government oflices were springing up, to say nothing of a fair-sized hotel. But the buildings to which most interest attaches are the Sirdar's palace and the Gordon Memorial College. The palace, which had been completed and occupied for some time, is a large and imposing though somewhat bald and ugly structure. It is built on the spot formerly occui)ied by Gordon's palace, and portions of the old foundations and walls have been utilized. At a little distance from the Palace a mass of scaflFolding and stone showed where the Gordon Memorial College was growing into existence. As we neared Omdurman the shadow of a cloud seemed to be hanging over part of the river, the edge of the shadow being clearly defined in an uneven line even at some distance. But a glance upwards showed no cloud. The ragged line which seemed to mark where the shadow 78 KNOWLEDGE. [April 1, 1901. ended and the sunlight began was in reality the point at which the Blue Nile, with its clear dark blue waters, joined with the White Nile, the waters of which are heavily charged with sand and have a whitish appear- ance. As we passed over the line of junction, the idea of the shadow still prevailed, and so definitely was the thick grey water separated from the clear dark water that no mixing appeared to be taking place. We steamed across the united rivers, which form the Nile of Egypt, and tied up to the bank at Omdurman along- side thi-ee of the gunboats which had played so impor- tant a part in the " river war." Near by stood the works where many an old steamer, which most engineers would have broken up for scrap iron — one at all events dating from Gordon's days — has been miraculously patched up and made to work again. There was much to be done at Omdurman, and the dust and heat as well as the extent of the place by no means facilitated matters. The town is a most be- wildering place. It is built on a fairly flat piece of bare desert about six miles long by an average of two miles wide. This piece of desert is a mass of low mud houses surrounded by compounds and separated by high walls. A few broad straight roads, which are mere sand, and innumerable narrow wdudiug alleys, intersect the col- lection of huts and compounds, while here and there is a yawning 23it, or an acre or so of broken-down houses, such as those in the Baggara quarter, which is now but a heap of mud. Although the place itself has a peculiar fascination, perhaps on account of its history and the many unlooked-for secrets these numerous walls may even now be hiding, there is not much of interest to see in Omdxu-man. The houses are mostly built on the same plan — four mud walls with a flat roof made of rafters covered with straw or matting, a verandah in front, and sand for the floor. The few which have two stories were formerly occupied by the Khalifa and his chiefs. The Khalifa's own house stands at the corner of an immense square some GOO yards long. Outside the house in the square one can see the remains of what was once a brick platform, from which the Khalifa iised to preach to his thousands of fanatical followers packed in the great square. There on the last day of August, 1898, he held his last review, inciting the assembled hosts in a vigorous harangue to fall upon the invading army of British and Egyptians, to drive them into the river and annihilate them, and there the dense mass of misguided savages clad in their patched jibbehs shook their spears and became mad for the blood of the accursed infidels. In 1900 in the same square a few orderly squads of Soudanese, dressed in neat khaki uniforms, might be seen industriously drilling to words of command given by a sergeant as black as themselves, with neither an English- man nor an Egyptian present. Yet most of these Soudanese were the same men who had thirsted for and spilt our blood such a short time before. That they were no less eager to fight one could tell by the fierce energy of their drill, but above them, near their former master's house, floated two flags side by side — the Union Jack and the Crescent and Star, and around them, working in the houses so lately occupied by their ignorant and brutal chiefs, were a few British ofiicers in their shirt sleeves administering the Soudan. Just outside the great square is a small enclosure surrounded by high walls, and in this may be seen a great heap of bricks with a square of arches round it — all that is left of the Mahdi's tomb, for ten years the most sacred and revered object in the Soudan. Leading out? of this enclosure is a compound with a small mud house, the English Officers' Club, and here every evening the Soudanese may catch a glimpse of the members playing tennis or racquets. One of the most interesting places in Omdurman, although now in l^^^^^^H^^^Bb -~..^ 1 1 * t W" -■ _;;^^- -^•->.-^ ' •:: ^-^r - ■ Mr' Kiiiiis ol tlje ALilidi's Tomb. ruins and difficult to find, is the " Saier,'' the awful prison in which Charles Neufeld and so many other victims of the Khalifa sjient years in torture. Slatin Pasha writes thus of the horrors of this place: — "A gate, strongly guarded day and night by armed blacks, gives access to an inner court, in which several mud and stone huts have been erected. During the day-time, the unhappy prisoners, most of them heavily chained and manacled, lie about in the shade of the buildings. .... At night the wretched creatures are driven like sheep into the stone huts, which are not pro- vided with windows It is a painful sight to see scores of hall'-suflocated individuals pouring out of these dens, bathed in perspiration, and utterly exhausted by the turmoil of the long and sleepless night." The walls round this awful place are now broken and crumbling, and only portions of the huts remain. But enough can be seen to make it almost impossible of belief that any of the crowd who were forced into these dens could have lived through one night. That many succumbed we know. Outside the huts in the small comjjound could be seen the remains of three or four brick platforms on which the most favoured prisoners were allowed to rest at night. To turn to pleasanter things. Of the birds of Omdurman itself there is little to say. There is not a tree near the town, nor is there any vegetation. Consequently there is little else but carrion on which a bird could feed. Kites and Egyptian vultures, || both excellent scavengers, are the most conspicuous birds. And all over the town are homely house sparrows,11 a little smaller and more brightly coloured than our familiar birds, but every whit as cheeky and pushful. Down by the river one may often see a striking black and white kingfisher,** hover- ing over the shallow water, and every now and again drop- ping down to the surface like a stone. If you watch carefully you will notice that this graceful action is repeated many times before the bird makes a successful plunge and rises with a fish. Across the river, on a sandbank, a few pelicans.tt sonic II 2f eophron percnoplervs, Jjinn. If Fassei- rufidorsalis, 'Bvchm. ** Ceryle nidis, Liiiii. ft Pelicanux onocrotalus, Linn. Ai'Bii. 1, 11)01.] KNOWLEDGE. 19 -graceful egrets and herous^i autl other wadiug birds may be distinguished. When once we got into the swing of things and began to learn om* way through some of the mazes of the town, preparations for our jom-uev up the White Nile did not take long. Time being precious I determined to spend as little, as possible in travelling, but to work thoroughly a small tract of country from Omdurmau south along the White Nile. With this in view we decided to travel entirely by land, as being a more thorough method of exploring the country, although much slower and more fatiguing than travelling by boat. Our task in Omdurman was to obtain permits and servants, and animals to carry oiir baggage and our- selves. At first we tried to buy camels, and several Ai'ab sheikhs were induced to make a parade of their beasts before us. Feeling sure, however, that such camels as were shown us would become the prey of dogs and vultures after a day's march, we waived their owners politely away. At this deadlock I learnt most oppor- tunely that His Excellency the Sirdar, Sir Reginald Wingate, through the agency of Bimbashi F. G. Ncwall, of the Intelligence Department at Omdurman, had most kindly already hired baggage camels for mo from the sheikh who contracts to supply the Government. This difficulty being thus pleasantly overcome w-e turned our attention to procuring our own mounts. Good horses and saddles were diilicult to obtain, and to feed horses in such a dry season would have been a difficult matter. Kiding-camcls wei'e expensive, and a doubtful luxury. We. therefore, fell back upon donkeys. But the donkey of the Soudan is a miserable little beast compared to that of Egyjjt, and although our animals, bought after a wearisome amount of bargaining and trials, carried us faii-ly successfully, we often wished for better mounts. We made a great mistake in using the wide wooden native saddles, which even with the aid of pads and a sheepskin became exceedingly uncomfortable at the end of a long day's march. Quite the mount for our journey would have been a bicycle. The desert tracks, at all events as far south as we travelled, are quite hard and smooth enough to make bicycling possible and often enjoyable. A permit to travel as far south as we cared to go on the east. bank of the White Nile was granted us, but we were prohibited on account of the unsettled state of the country from journeying on the west bank at all. This somewhat altered my plans as I had hoped to be able to make several excursions into Kordofan from the west bank. Licenses to can-y arms and to shoot weie also necessary. By licensing each gun, rifle, or revolver, instead of the user, the authorities make a distinct gain for the Revenue. Some very fair game laws have also been drawn up for the Soudan. No one is allowed to kill the zebra or the ostrich. A special license authorises the holder to kill a very limited number of adult male buffalo, elephant, giraffe, hippopotamus, and rhino- ceros, and for each animal killed, a special fee has to be paid. A less expensive license allows one to kill antelope, gazelle, and warthog. All other animals and birds may be shot by the holder of an ordinary gun license. These regulations might well be revised and made still more useful, and no doubt Capt. Stanley S. Flower, who has lately been appointed Director of the Soudan Wild Animal Department, will see to it that better protection is afforded to many scarce animals, such as giraffes and some of the rarer antelopes. Zl Eerodias ralloidef, Scop; 'fferoilian garzelfa, Linn.; Ardea purpurea, Linn. FLOWERING PLANTS, WITH ILLUSTRATIONS FROM BRITISH WILD-FLOWERS. By 11. Lloyd Pkaegeh, b..v. II.— CONCERNING LEAVES. The stems of plants, as stated in my last article, arc the framework on which the leaves and flowers ai'o spread out to catch the light and air, and we find definite relations existing between the form, position, and strength of stems, and the shape, weight and func- tion of the organs which the stems support. Tlio branches of an Apple or Pear tree have to be sufficiently strong not only to withstand the stress of winter gales, and the burden of the wealth of blossom and foliage of early summer, but also the weight of the abuiid.ant fruit of autumn. It is interesting to note that among our cultivated fruits, strength of stem has not kept pace with the increase in weight of fruit due to artificial selec- tion, so that in gardens our artificial fruits must needs, ill a season of abundance, bo supported by artificial stems — by props and crutches, lest, like the legs of the prize turkey in the " Christmas Carol," the branches might snap like sticks of .sealing-wax. In evergreen trees, the weight of snow is a serious contingency that must not be neglected. Nor must the chance of accident owing to wandering animals be left out of account. The young Ash saplings, a few feet in height, ai-e as pliable as willow-wands, and spring back into their places as we force our way through them ; but the knobly twigs of an old Ash tree, which swing clear m the air high over- head, are brittle, and snap across if we attempt to bend them; the elasticity of the whole bough is sufficient to bring them safely through the heaviest stoi-m. Between the form of a twig and that of the leaves which it bears we can generally at once perceive a relation. The little leaves of the Birch are borne on twigs slender as a piece of twine. The Oak and Elm, with larger leaves, require a stouter twig for their support. The Svcamore and Ash have twigs which are stouter still. The large leaves of the Horse Chestnut are boruo on very thick twigs, in which the principle of the hollow column is introduced. The arrangement of the leaves on the stem, or -phyllo- taxis, is a question of the first importance. The leaves must be so gi-ouped that all may receive as much light as possible. So far as can be arranged, there should be no overlapping, nor should any of the available space be wasted. On the stem of the Ash, or Sycamore, or Teazel, the large leaves arc arranged in alternate pairs, the direction of the axis of each pair being at right angles to that of the next. Thus two spaces or inier- nodf.t separate any pair of leaves from the nearest pair which, being placed in the same position, might over- shadow it. This is a very simple case, which we shall find to be the rule when we examine plants in which the leaves are borne in opposite pairs. When loaves are borne in whorls of three a similar rule will be found to hold good. The position of the leaves of any whorl is such that they are vertically below or above the -"ji'io-^ between the leaves of the next whorl. It will be seen at once that the amount of light received by each leaf is materially increased by thris arrangement. If m a theatre wo can look between the heads of two people in the row immediately in front of us, the head of a person in the next row beyond, even though directly before us, does not much interfere with our view of the stage. In most cases, however, the arrangement of the leaves on the stem is much more complicated than so kNOWLEDGE. [April 1, 1901. this. The leaves usually emerge singly. If we join by a line the point of emergence of a leaf with that of the next leaf above it on a stem, and that again with the next, a spiral will be the result, along which at equal intervals we reach the noih^. or points where leaves are borne. And the distance between these nodes will be always found to bear some definite relation to the total length of the spiral line in making one complete revolu- tion round the stem. If the distance from node to node is one-half of this whole distance, it signifies that the leaves are borne alternately on opposite sides of the stem, each leaf being vertically below the second one higher up the stem — a very common arrangement. Or the leaves may be borne three to each spiral revolution, so that the position of each loaf shifts one-third way round the stem as compared with the preceding leaf. If we look along such a stem, the leaves will appear to be borne in three vertical rows, with an equal angle between each. Examining some other jjlant. we may find that we have to go as far as the fifth leaf before we find one vertically above the one from which we started, and if we measure the horizontal distance from any leaf to the next above or below it, it will be found to equal two-fifths of tbe total circumference, so that we have to go five times two-fifths way round the stem, or two complete revolu- tions, before completing the cycle. This is called a two- fifths phj'llotaxis. In many other cases, the arrange- ment is immensely more complicated, and need not be entered on here. What is important for lis to note at present is that by means of this orderly mathematical arrangement, the leaves are so distributed that each fulfils its functions to the best advantage. The shape of leaves offers an almost inexhaustible field for observation and scientific speculation. Mr. Rviskin has said: — "The leaves of the herbage at our feet take all kinds of strange shapes, as if to invite us to examine them. Star-shaped, heart-shaped, spear- shaped, arrow-shaped, fretted, fringed, cleft, furrowed, serrated, sinuated, in whorls, in tufts, in spires, in wreaths, endlessly expressive, deceptive, fantastic, never the same from footstalk to blossom, they seem per- petually to tempt our watchfulness and take delight in outstripping our wonder." The size of leaves will naturally vary inversely as their number. A plant of a certain size — say a tree — will require a certain total area of leaf for the manufacture of the recjuisite amount of plant-food. If wc cut the branch of a Horse Chest- nut and of a Beech where each had exactly a diameter of one inch, or two, or six inches, and counted and measured the leaves on each, while the number of Beech leaves would immensely exceed the number of Chestnut leaves the total leaf-area would be about the same in each case. This area of green leaf, then, must be spread oiit to the best advantage. In this connection, a beautiful relation between the shape of loaves and their arrange- ment on the stem may frequently be remarked. Lay a twig of Beech on a sheet of white paper, and note how small are the interstices between the leaves through which the paper may be seen. The shape of the leaves, and the intervals at which they are borne, are so related that an almost continuous expanse of green is offered to the sunlight. A more remarkable case may be seen in the Lime, whose leaves are quite inequilateral, being contracted on one side at the base and expanded at the other, in order the more exactly to fill the space which is available. The Elm likewise furnishes a beautiful example of closc-titting leaves. In most trees in which, like the Beech, Hazel, and Elm, the leaves lie in close-ranked rows in the same plane as the twig which supports them, we find more or less oval leaves, their breadth varying with the space between the leaves, i.e., the length of the internode. In trees such as the Horse Chestnut or Syca^ more, on the other hand, the leaves grow in opposite pairs, and are typically arranged on upright twigs, the leaf-stems projecting at a wide angle from the twig, with the surface of the leaf horizontal. In this case space is not so curtailed ; the leaf is lai-ger, and more or less circular in outline ; and the great increase of length in the internodes, as compared with the trees lately con- sidered, prevents a too great overshadowing of the lower leaves by those higher up the shoot. In plants which have a very short axis — which have in popular language " no stem " — a difficulty arises as to how all the leaves shall receive a due amount of light, since all arise from the same point. This is met in several ways. The leaves are often placed at different angles, the outer leaves, which are the lowest and oldest, spreading horizontally near the ground, the newest rising almost vertically in the centre, the intermediate being disposed at various angles between these extremes. Another solution of the difficulty is effected by a con- tinued growth of the leaf-stalks, each leaf steadily push- ing itself outv\'ard so that the whole form a slowly expanding circle, in which each leaf-blade successively occupies a position commencing at the centre, ending at the circumference. Such leaf-blades, it is almost need- less to say, are widest at the extremity, since that is the portion which receives most light ; often the blade is roundish, and placed at the end of a bare leaf-stalk, which pushes it further and further from the centre, as other leaves arise. Such arrangements are well seen in many of our biennial plants. During their first season they form a close leaf-rosette of this kind, which manufactures during the summer and winter a supply of plant food to bo stored for the building up of the Winter Ir.if- rosette of the Sea Stork's-bill. Tt-om a p/((itog/ap7i 7.1/ Mr. H. J. Sev.mot'K. tall flowering stem of the succeeding year. The Stork's- bills {'tee figures). Crane's-bills,- Teazel, and other plants will occur to the reader as examples. In the case of a few British plants, the normal position of the blade of the leaf is not horizontal, but vertical. The Black Poplar and its relation the Aspen furnish well-known instances. If we examine the stalk of an April 1. 1901.] KNOWLEDGE. 81 Aspen leaf we notice that while the lower part of it is circular in section, the part near the leaf is much flattened, permitting free movement in the plane of the leaf-blade. This, together with the position in which the leaves are borne on the twigs, causes the leaves to hang vertically. One result is that the light can stream almost unbroken through the branches even to the ground below, the wealth of foliage producing but a faint tremulous shadow as the leaves rustle in response to every breath of air. Well does Scott, seeking for a simile, say in ilarmion: — " A'arinble as the shade By tlie light quivering a*j)cn made." A peculiar point about these vertical leaves should be noted. In discussing the question of plant-food in Know- LEncE last year, Mr. Pearson explained the important functions fulfilled by the leaves; how on the under side of leaves are situated a myriad of tiny openings (^tonuita, mouths) through which the plant absorbs carbon dioxide from the atmosphere, and having taken from it the carbon, liberates the oxygen, the stomata being also used for the escape of the surplus water of the plant. Now, the reason why these mouths are situated in most plants on the under side of the leaves is no doubt be- cause they are thus protected from cold and rain and storm, and their work less interfered with. In the Aspen, with its vertical leaves, either side of which is eqtially exposed to atmospheric vagaries, there is nothing to choose between the two sides as regards the position of the stomata, and as a matter of fact, these are equally distributed over both sides of the leaf. A further modification of this kind we may find in plants like the Water-lily, the leaves of which float on the sur- face of water. Following out our line of argument, we would expect to find the stomata confined to the njiper side of such a leaf, so that they may be in contact with the atmosphere, and this is exactly what we do find. Plants whose leaves are all continually below the surface of the water, such as the Water Lobelia and many Pond- weeds, must perforce be content with obtaining the carbon dioxide which they require from the siiiall quantity of that gas which is to be found dissolved in the water. The protection of leaves against various hurtful agencies next claims our attention. The typical leaf has its upper surface built of strong closely-placed cells, to offer a stout resistance to rain and hail, and to ficst or overpowering sun-heat. In hot dry weather, when great evaporation is taking place, the plant can close up all its stomata — shut down, so to speak, all the sluices by which the water employed to convey dissolved salts from root to leaf is allowed to escape, and thus retain an abundant water-supply in spite of parching heat. But in arid ground, such as sandy wastes or sea-beaches, further protection against over-transpiration may be desirable, and this is frequently effected by impervious varnish-like layers on the upper surface of the leaves, or by dense coverings of hairs. Layers of impermeable corky cells in the epidermis or skin of the leaves are also ' frequently to be found in plants liable to ex- cessive transpiration. Such impermeable leaves are beautifully developed in plants like the Stonccrops, which, gi-owing in dry ground and on rocks, and being liable to long-continued drought, store up in their leaves a copious water-supply. Such reservoir-leaves are greatly developed in the "plants of desert countries. Pro- tection against the often fatal effect of frost is likev.ise afforded by a thickening of the cuticle of leaves, and especially by felt-like coverings of hairs. In some note- worthy cases protection against cold is effected by means of movement on the part of the leaves. The most familiar examples occurring among our native plants are furnished by the trifoliate leaves of many of the Clover family. As evening approaches, the Clovers and their allies fold their three leaflets together by means of an upward movement; the juxtaposition of the leaflets retards loss of heat, and the vertical position which they thus assume has the same effect, tending to check the radiation of heat to the cold sky overhead. Tlie Wood Sorrel, which, though of a quite different order, has leaves which resemble those of the Clovers, effects the same object by folding its leaflets Jounwdrfl^. Wet, which by lying on the leaves might hinder trans- piration, must also be guarded against; a danger which in many species is obviated by means of a waxy excre- tion, especially on those parts of the leaves where the stomata are situated; on which, as on an oily surface, water will not lie. Another danger to which plants are exposed, and one which we might think they would be powerless to meet, is the attacks of browsing animals — animals of all sizes, from minute insects up to gi-eat munching cattle. But to note how perfectly such defence may be provided for we need only look at our common Gorse, which boldly invades the pasture, protected by its impenetrable chevaux-de-frise. This plant, indeed, seems to have put so much of its vital energy into the production of spines, that it has none left with which to produce leaves, and, as already remarked, the making of plant-food has to be can'ied on by the green and much-branched stems. The beautiful tribe of the Thistles naturally comes to Winter leaf-rosette of the Hemlock Stork's-bill. From a photograph ty Mr. H. J. Sf.vm,-juk our minds in this connection. Armed with innumerable spines of the most exquisite structure, sliarper and more delicate far than needles, the Spear Thistle and Marsh Thistle raise their tall and graceful forms untouched amid the close-browsed herbage, and without fear of molestation — save from man, with his implements of iron — open their flower-heads to the sun and the insects, and scatter their numberless winged fruits to the wind. In the Thistle the spines are borne alike on the stems, leaves, and involucres or outer whorls of the heads of flowers. The Holly is an interesting case. In low bushes the edges of the leaves are provided with strong R2 KNOWLEDGE. TApeil 1, 1901. spines ; but when the bush grows into a tree, and bears leaves far above the reach of browsing animals, the un- necessary spines disappear, and the edges of the leaves are entire. In the Blackthorn and Hawthorn, the strong spines are modified branches ; and we may observe that they are much more numerous in young plants than in old biishes. A more complicated mode of protection is foimd in the Nettles. They are furnished with hollow hairs, filled with a virulent fluid, and bent at the tip. A slight pressure causes the curved extremity to break across, leaving a slender tube, tapering to an extremely fine point, which easily enters the flesh and discharges a portion of its venemous contents. So far we have considered leaves as fidfiUing their normal functions of producing plant food by means of chlorophvll cells. In conclusion, brief reference may be made to various exceptions; for the production of plant- food is not necessarily carried on by leaves, nor is the use of leaves altogether limited to the production of plant food. First, leaves may be dispensed with, as we have already seen in the case of the Gorse. The stem may be modified to supply the place of leaves, as in the Butcher's Broom, whose flattened " leaves " are really branches, as we see when we find flowers and fruit borne on these flat leaf-like structures. In climbing plants the leaves, or a portion of them, are frequently converted into tendrils, often endowed with a marvellous sense of touch, for gi-asping supports and thus aiding the plant in its upward climb through surrounding herbage to the light. This is seen in many of the Vetches, the upper end of whose leaves are modified in this fashion. In the Yellow Vetchling (Lnfhyrus aphaca) a further modification has taken place. The whole leaf is converted into a tendril, while the stipules (the. usually small pair of leaf-like appendages that often grow at the point where a leaf joins a stem) are enlarged into a very respectable pair of " leaves." and manufacture food while the tnie leaf helps the plant to climb. Of other much stranger modi- fications of leaves Mr. Pearson has written in Know- ledge last year. Vol. XXIII., pp. 245-6— of the mar- vellous tentacles which the leaves of the Sundew bear, which catch and digest insects; and how certain leaves of the Bladderwort are converted into snares on the most approved rat-trap plan, for the same purpose — some of the most mar\'ellous fairy-tales of botany. Astronomical. — The recent observations of Eros have resulted in the remarkable discovery that the planet is probablv accompanied by a satellite nearly as large as itself. The first mdication of this fact was the detection, by Dr. Oppolzer, of variability to the extent of about a magnitude in the luminosity of the planet in the period of a few hours. Confirmation ■ of the variability has been obtained by two French astronomers. M. F. Rossard found the magnitude to range between 9-3 and 11 0 on February 14th, loth, and 16th, and concluded that the period was 2h. 22m. M. Ch. Andre believes that his observations indicate a period of about six hours, and states that the light-changes are similar in character to those of the well-known variable TJ Pegasi ; the system being probably composed of two asteroids, with diameters in the proportion of three to two, the plane of revolution passing through the earth. As the inclination of the plane of revolution to the line joining Eros and the earth changes, corresponding differences in the variability may be expected. There is every indication that adequate records of the total eclipse of the sun on ilay 18th will be obtained, if the weather should fortunately be favourable. Mr. and Mrs. Maunder will be stationed in Mauritius, where they wiU work in conjunction with Mr. Claston, the Director of the Royal Alfred Oliservatory, In Sumatra, where the duration of totality on the centi'al line is over six minutes, there will lie quite an army of astronomers, including Mr. Dyson, of Greenwich; Mr. Newall, of Cambridge; parties from the Lick, Yerkes, and Washington Observa- tories, and a Dutch expedition under the direction of Dr. Nijland. Photographs of the corona on a large scale, to show the details near the sun's limb, and on a smaller scale to depict the streamers, will be attempted, in addition to spectrum photographs with sUt spectroscopes and prismatic cameras. An extensive comparison of sun-spot and magnetic data which has been made by Father Sidgreaves, supports the view that the distinct connection disclosed cannot be due to a direct action of the sun upon the earth, but rather that there is a common cause for both. Large sun-spots are frequently unaccompanied by magnetic storms, and the cause therefore does not always affect both the sun and the earth at the same time. The discovery of sixty-four new variable stars is announced in Harvard College Observatory Circular No. 54, a large proportion of them having been found from the presence of bright hydrogen lines in their spectra. Many stars whose spectra are of the fourth type also prove to be variable. These varialdes have been divided into two classes. First, those in which the variation is so great that it is obvious to the most inexperienced obsers"er. Secondly, those in which the variation so far detected is small, about half a magnitude to a magnitude. In each of these cases, two or more experienced observers, who are accustomed to accurate measures of photographic brightness, are satisfied that the change is real. — A, F. Botanical, — Under the heading "' Economy in Nature," in Turreya, a new publication of the Torrey Botanical Club, Mr, P, A. R\db?rg mentions a cherry tree which, till quite recently, giew in New Orange, New Jei-sey, It had an unusually thick trunk, which divided at about seven feet from the ground into two trunks. At the junction of these was a large hole, showing that the stem was decayed and hollow, A strong wind tore away one of the trunks, when it was found that the hoUow stem was partly filled with refuse, consisting of decayed cherries and leaves. Into this a stout root, originating from the margin of the hole, had gi-own, and had then sent off numerous branches into the decaving stem of the tree, which was thus actually preying upon itself, BracJi t/ifel ma Biiigeri, a new Asclepiad with an edible tuber, is described and figured by M. A. Chevalier in the Revue des Cultures Colotuahs for February 5th, It is a native of the region of the Upper Niger. The tuber resembles in taste the Jerusalem artichoke, and though only slightly nutritive, its value as a food is augmented owing to the fact that it can be procured when supplies of rice and millet are exhatisted. Other species of Apbii. 1, looir KNOWLEDGE 83 BracIiysUhiia, aud a Ceropeffia, are cited, all of which possess edible tubei-s. The Comjites Beiidus for Fel>riiary 11th contains an interesting paj^er hv M. Bernard, eatitled " Sur la tiiber- culisation de la Pouinio de terre," in which it is shown that the potato-tuber is produced bv the action of a fiiiiijus, Fitsariiim SoliDii. This fimgus is always present in the tubers, whether healthy or diseased, and attacks the growinjj subterranean stems, inducing, it is supposed, the arrest of their growth and the development of the tubers. — S. A. S. Cyclones. — At the meetiusj; of the Eoyal Society of Edinburgh on March Ith, Mr. John Aitken, f.r.s., contri- buted some additional notes to his paper on " Dynamics of Cyclones aud Anticyclones," read a year ago. He was of opinion that cyclones are found over those parts of the earth where there is a high temperature. The movement of the storms in our own area is in a north-easterly direc- tion, because the winds on the north-west side of the anticyclones were generally stronger than those on the other sides. The cyclone is formed out of air from the south travelling towards the north and rotating at a greater rate of velocity than the surface of the earth. He asked: "What is a cyclone?" aud answered his question by sayiug that it is caused by hot air ascending and drawing in air all around it, that it is formed by the anticyclone, and that it is on the north-west side of the anticyclone that we get the strongest winds. The general theory is that a cyclone is not an independent power at all, but is simply a large eddy produced by the action of two anticyclones. Cyclones may be divided into couvectional and dynamical, and the distinction may be explained in this way. If the cyclone is couvectionally driven, the currents move towards the centre, but if dynamically driven they will move s])irally outwards. The exhaustive investigations made at Wash- ington show that the general tendency is inwards, and, further, that in convectionally-driven cyclones the velocity increases towards the centre, but when dynamically driven the velocity does not increase. Mr. Aitken also spoke of the great storm tracks from America, the one passing to the north of the British Isles, aud the other to the south ; and of how at certain seasons the one moved southwards and the other noi'thwards, aud so decreasing the inter- vening space aud vice versa. However powerful an anti- cyclone might be, a vast amount of energy is without doubt developed in the cyclone itself ; but the cyclone is governed to a very large extent by the anticyclone. At Washington it is held that the anticyclone is much the more powerful of the two. It has also been ascertained that they sometimes extend to 6^ miles, although formerly it was thought they were much thinner. Professor Dobbie held that a cyclone was a vast eddy between two currents — the polar aud the equatorial — but that view is somewhat modified now. In all cyclones one side is dry and cold, and the other moist and warm ; the reason being that the cyclone sweeps before it all the warm surface air and brings down i?i its wake higher, and therefore drier and colder, air. As there is greater violence of winds in cyclones than in anticyclones, there must be some strong source of energy in the cyclonic areas. It is still evident that to a great extent " the wind bloweth where it listeth. aud no one can tell whence it cometh and whither it goeth," as was said two thousand years ago. Yet, as Mr. Aitken has been able to calculate the particles of dust in the air, which were considered to be " numberless," he may yet be able to lay down some sound general laws for the regula- tion of the cyclones and anticyclones to which he has for some time been giving his valuable attention. — J. G. McP. ENTOMOLOoicvi. — Professor Wheeler's observations on .American "driver" ants and their "guest" beetles (mentiouod in Knowledge for February, pp. 32-3), have been followed by the I'ublication of a valualjle paper on the same subject by Fat her Wasinann, in the ZooIck/. Jahrh. (abf. f. Sijst. ii.s.ir.), XIV., 1900, pp. 21 0-28!), pi's. 13, 11). The inquilines described in this papor arc rove beetles (StaphyiinidiE). A new genus, £cito, has e.xcited great interest. In 1860 Peth^-ick brought home two live si)eci- meus, which were exhibited in the Zoological Gardens and attracted much attention by their singular aspect. Out- wardly the bird is chiefly remarkable on account of its enormous bill, which is shaped somewhat like the head of a whale, hence one of its names, but it is in other resjiects distinctly weird-looking, having a gaimt grey body, long legs, and a large head surmounted by a little curled tuft, and a scowling expression of the eyes. It has many struc- tural peculiarities which anatomists have had few oppor- tunities of examining owing to the great rarity of the bird in collections. The British Museum, for instance, up to a few months ago only possessed one skin. The bird itself is sufficiently numerous in the great marshes of the White Nile south of Fashoda, but it is extremely shy and difficult of approach. Since otir reconquest of the Soudan several specimens have been obtained on the tributaries of the White Nile, while juist lately Sir Harry Johnston has sent to the British Museum a specimen of the bird shot, at Entebbe, on the north shore of Lake Victoria, East Africa. Great interest attaches to this specimen, which is now on exhibition in the British Museum, because hitherto the only known locality for the shoe-bill was the White Nile, to which river it seemed to be entirely, confined. At a recent meeting of the Linnean Society, Prof. E. Kay Lankcster read a paper on the systematic position of Jiluropus vielanolcucus, with notes on itvj osteology by Mr. Lydekkcr. The animal in question is an inhabitant of eastern Tibet, and has hitherto been very generally regai-ded by English zoologists as an 84 KNOWLEDGE. [Apeil 1, 1901. absn-ant kind of bear, distinguished by its black and whits coloration, ajid the peculiar structure of its teeth. The author now showed that it is really a near relation of the panda {Jilurux fulgcmi), of the Eastern Himalaya, with which it agrees very closely in the structure of the skull and limb-bones. Both animals may now be regarded as members of the, otherwise, American family Procyonidse (raccoons), of which they will form an aberrant group. For the tiue panda the name of. Hima- la>au. 1)1- I iit.'-':iile'l hnmla may Iih Hclo[.ied, while for the other animal the title of great, or short-tailed panda will be appropriate. Tht" oniiiu of mammals, as deduced from a study of the occipitil condyles of the skull, forms the snhjeet of an important paper communiciited by Professor H. F. Osl'orn to the American SoturaJisf for December In reptiles the condvle liy which the skull articulates with the vertebral column is sin Aiean iijnr, HJtli llic Limit Equitlorial C'lmde of the I'liris Observatory. Srale : — Diameter of Moon, 2t inelies. Moon's Age, 20(1. 5f)li. April 1, 1901.1 KNOWLEDGE. R.' Palus Nebuliinim. The first is seen as a iMther shallow de|iressiou, str-tchinLr from Archimedes south-west to the Aj>euniues, aiul out off from the rest of ihe sea l\v the hii;h ruartred iiri^iuJ that seems to hive overflow**!) from Arelii- niedes on the south, and bv the "aureoles" of Autolvcus on the north. Tlie Pahis .V'etmlarum lies north of Avis- tillus, jind is bounded bv the ridges which conuect tha'' great riuire'l pla.n with Autolvcus on the south and with Cassini on the noith. The Sea oT Cold is too mneh £oreshortf»ned for the detail on its floor to be elearlv made out. It would seem to resemble the Sea of Serenity rather tbau the Sea of Kain. and the position of Eirede A on its intersecting- nd^es eertainlv seems to recall the position of Bessel. J>istant as Aut'ilycus, Aristillus and (\assini are from the Caucasus mountains, they yet seem to have exercised some local iuflu-'Uce on them. MJI. Loewy and Puis'ux point out that if lines are drawn jiarallel to that from Autolycus tbroui^rh the ereat pass, through the centres of Aiistillus Theaeletus, Cassiui and Eudoxes, these lines ■will all lie alonpf depr»-ssions in the mountain range. Another feature that they point out is the deep depres- sion that occurs at the ■ utside base of the craters and of the mountain ranges. This is well seen round Archimedes, along the base of the Alps west from Plato, both on the north side and on the south, and most markedly on the eastern side of the Caucasus where it crosses the Alps, and distinctlv, though less markedly, on the western side. These two depressions in tlie meridian line crossing the five depressions which pass through the great craters of the Sea of Rain, and through Eudoxes, divide up the Caucasus range into four great rectangles, and the mountains north of Eudoxes are so divided from the rest of the range that they appear but as isolated peaks. The two most important and most beautiful ringed plains shown on the photograph are those of Archimedes and Plato. Of nearly eaual size, both have the same regular almost unbroken rampart, both have their interior plains but slightly depressed, but the floor of Archimedes is brilliant, and the curious dark bands as it crosses the meridian at right angles are easily seen. The floor of Plato, on the other hand, is very dark, and no detail can be made out in this photograph. MM. Lo^wy aud Puiseux attribute the bands on the floor of Archimedes to the influence of the two large adjacent craters, some pointing towards Aristillus at-d some to Autolycus. Plato, the " Black Lake," as Hevelins called it, is the best example of those plains which become relatively darker as the age of the moon increases. CONSTELLATION STUDIES. By E. Walter Maunder, f.r.a.s. IV.— BOOTES AND HERCTLES. Theee bright stars ride the northern heavens, three stars so equal in magnitude that our highest authorities differ as to the order in which they should be classed in bright- ness. All three are above the horizon in the April midnight, but whereas Yegaand Capella are couiparatively low down in the east and west respectively, Arcturus is now approaching the meridian. Arcturus is one of the easiest stars to recognise in the entire sky. If w-j start from the Pole Star, we find that the last star in the Plough Handle is just halfway to Arcturus ; or the curve of the three stars of th : handle of the Plough, if continued, seems to bring us round to the same place ; or reverting to our two last studies, Denebola of Leo and Spica of Virgo and Arcturus mark out a triangle, almost equilateral. The star owes its nunc to its nearness to the Bear. It is Arcturus. the " Watch' r of the Bear." It is now the brightest star in the constellation Bootes, the Herdsman, but in the catalogue of Ptolemy it is not includi'd in the actual figure, but is an "unformed" star belo«' him. There seems to have been some reason for ihi.s exclusion, for Theou and Hesychius call Bootes, Orion, and when Arcturus is excluded, the principal remaining stars of the constellation m ike up a representation, pal" and distorted it is true, but a representation for all that of the most glorious constellation of the sky. This circumstance may explain an allusion iu Isaiah xtll. 10, widch has puzzled many commentators, " The stars of heaven and the constellations ther. of." The word "constellations" is in the pluralf and is the same word \diich is in the s ngular in Job IX. 9, .'ob xxxvtii 31. and Amos v. 8; and which is iu each case translated with great probal)ility "Orion." Here then it may stand for the two Orious, Bootes being one. However this may lie, the resemblance between the two constellations will be near enough to help the student to trace out the figure. Arcturus stands nearly midway between the Herdsman's two legs, marked respectively by the stars Ela aud Zeta ; above Arcturus are the three belt .stars, Hho, Sigma, aud Epsilou, I'ipsilon being much the brightest. Above we find (iamma and Delta marking the shoulders, whilst Beta takes the place of the cluster of small stars which denotes the head of Orion. Arcturus and Gamnia form two points of an equilateral triangle with K|)silou in the centre; the third point is formed by Alphecca, the Hroken Platter. The reason of the name is readily seen, since right and left of Alphecca are four other stars, two on each side, making up a semi- circle, and suggesting to the old Atabiau star-gazers a broken plate held out by a beggar to receive alms. This very sordid title contrasts poorly with its classical name, " That Crown which I >ionyso3 placet! Of Ariiidne dead, a glorious sign." The constellation though so small is, from its shape and its nearness to Arcturus, very easy to find. Or the old rhyme may guide us if we turu back to Virgo, aud pick out Epsilou, the " Herald of the Vintage." " From Epsilon iu Virgo's side, Arctie-us seek and stem, And just a- far again you'll spy Corona's beauteous gem ; There no mistake can well befall e'en him who little knows. For bright and circular, tlic Crown conspicuously glows." The small size and neat arrangement of Corona make it a pretty object for the opera-glass; aud in 1866 it afforded a grand chance for the naked-eye observer. For on the night of May 12th. in that year, the cimstellatiou siiddeidy presented an uu wonted shape. E[isilou, the star of the five furthest to the east, was overshadowed by a new aud bright companion which outshone Alphecca. This was T Corouae, the first "new star" to appear since the invention of the spectroscope. Less brilliant than the new star in Perseus which has so suddenly blazed out upon us, it created, as the first example of the kind that had occurred in the new era of astronomy, an even greater sensation ; and the discovery in its spectrum of the bright lines of hydrogen aroused the utmost interest. Six nova- have appeared since the date of T Coronae. including the one so recently discovered by Dr. Ander.son. So far, however, as the relatively incomplete observations of its spectrum changes go, they seem to point to T Corona being a nova of a different order from those which have succeeded it. A line from Gamnia Bootis through Theta Coronae, the most westerly of the five stars of the " Broken Platter." brings us, at an equal distance beyond, to Beta in tlie constellation of the Kneeler. This is not -i luilliuit 86 KNOWLEDGE. [April 1, 1901. constellatioD, liaving no stars so bright as the second maguitude, but it can be pretty easily traced out. Taking Beta and tlie somewhat fainter star Gamma, just below it, as the root, the stars map out the calix of a gigantic lily ; Gamma, Beta, Zeta, Eta, Sigma and Tau, six stars in a beautiful curve, sweeping round the little constellation of the Crown, forming the western outline of the flower. Hercules is the name now uuiversallv ascribed to this the current outlines of the constellations, regarded as making the true Dragon's Head. The thu-d curve of the great lily of Hercules extends from Gamma and Beta, through a well marked line of stars, Delta, Lambda, Mu, and Nu, to the little constellation of the Lvre, the principal star of which is the great blue brilliant Vega, the worthy rival of Arcturus and Capella, if not superior to either. The __^xyn XVII XVI XV XIV DRACO XIII I '• / •- • \ • •44 { ^ 24 CANES XI Ip URSA MAJOR r -x 47 •c ' CORONA > •(■ •&\ B00TE5 •S HERCULES • - - - I "5 w COMA ., •— f 1 "IT •." 1 . 7 12 s •2, -7 1 '.'■- •v CRATER star Map Xo. -1 ; The Region of Bootes and Hercules constellation, but the name was foisted upon it in com- paratively recent times Aratus sings : — ■' A labouring man next rises to our sigbt, But wliat Ills task or wlio this honoured wight X"o poet tells. Upon his knee he bends, And hence bis name, Engonasiu, descends. He lifts his suppliant arms and dares to rest His right foot on the scaly dragon's crest." The first suggestion that this Kneeler was the great national Hellenic deity, seems to have been due to Panyasis, the uncle of the great historian, Herodotus, Li a poem "n the sul-iject of the great national hero, in order to do h:m the greater honour he sought to identify him with the unnamed wrestler of the constellation. The fact that desj)ite this effort the identification had entirely failed of adoption 200 years later, is as near positive proof as we can get, not merely that it was uot known whom the constellation represented, but that it was kuowu that it did not represent Hercules. The second curve of Hercules runs through the stars Gamma, Beta, Epsilon, and Pi and Iota ; Iota making a diamond with the three stars in the Head of the Dragon, Beta, Gammi and Xi, This diamond. Proctor, in his ingenious Vmt usuilly quite unauthonsel alterations of brightness and the intensely blue light with which it shines render Vega a very easy object to pick up, but if an alignment is required, a straight line from Arcturus through Alphecca to Zeta Hercules leads almost straight to it, Zeta being halfway. " There is the Shell but small. And this. whUst yet Encradled. Hermes pierced and called it Lvre ; Fronting the Unknown Form" (i.e., the Kneeler) " he set it down When brought to Heaven." The principal stars of the constellation are very easy to recognise. Vega forms one of the points of a little equi- lateral triangle, the other two angles of which are occupied by Epsilon and Beta. Epsilon is to very keen sight a naked-eye double; the opera-glass separates the tivo stars at once, and no great telescopic power is required to show each star as itself a neat little pair, Zeta marks also the upper angle of a little rhomboid, of which Beta, Gramma, and Delta mark the other angles. Each of these stars is an easy double for the opera-glass ; Nu and Lambda being companions to B.Ha and Gamma respectively. Beta, is one of the most interesting of short period variables ; its period being two hours short of thirteen days, in which time it passes through two maxima and two minima, the minima being, however, of unequal brightness ; but as even April 1. 1901.1 KNOWLEDGE. iV ■when faintest it is of inaijuituclo 4^. it is always well within tho iirasi. of the nalioJ-eve ohscrver. The Milky Way (lows aiross the S.E. an:;lo of the ooustella- tion, and this, with its daz/.liui; leader, its uunierous pairs, its beautiful fields and woudtu'ful variable, renders it a tine region for the opera-glass observer. To the naked-eye astronomer, it is also noteworthy as the home of the swift meteors of April ^Oth — the Lyrids— their radiant point being just on the boundary line between Hercules and Lyra. The constellation is always shown now as an eagle with a harp slung round its ueek, aud the name of the principal 'CYCNUS oR^co ,*''" .•*^ ^ OAMELOPARDUS GEMINI Jj, '\ cqjONft • ^^'j V t >^ 'fit tO"^ Tlic Midniglit Sky f.u- L<.iuloii, I'.lOl, Apvil. Star, Vega, refers to this design, since it comes from the last word of the Arabic expression, Al nesr al wakl, the "falling" or "swooping eagle"; in contrast to Aqnila, the principal star of which we now call Altair, that is to say, Al )iesr al tair, the "flying," that is, the " soaring eagle." The head of Hercules is marked by a beautiful orange coloured star. Alpha Heroulis, Has al gethi, the " head of the Kneeler," forming the southernmost point of a lozenge of which Beta, Zeta and Delta Hercnlis are the other three points. Alpha Herculis is notaljle in the spectroscope as presenting one of the finest examples of the tliinl or banded type of sj^ectrum. 0.otict6 of Boofeg. '• A TeXtBOOK OF ZOOLOIIY, TP.KATF.D FROM A BlOI.OlWCAL Standpoint." By Dr. O. Scbmeil. Translated by R. Rosen- stock, and edited by J. T. Cunningham. P.irt III. (A. and (.". Black. 1900.) Price Ss. 6d. — The two previous parts of this work were noticed in our Xovember issue, where reference is made to the general scope of the work, and the class of readers for whom it is intended. The present part, which treats of Invertebrates, completes the work. Were it not for the un- accountable omission of certain most important groups, such as the Brachiopods and the Tanicates, not to mention that most remarkable worm Balannr/Iossvii, we should have been enabled to bestow higher commendation on this jiortioa of the work than, as matters stand, we feel justified in doing. If, however, we discount these omissions, there is little doubt that the subject as a whole is treated in a satisfactory manner, and in a way which c.in scarcely fail to prove attractive to the pu])il. As in the earlier parts, attention is concentrated on pliyaiology and habits rather than on morphology ; and tlio ilcsciiptions of the transformations undergone by insects, as well as of tho mar- vellous developmental liistory of the luimerous kinds of intes- tinal and othir parasitic worms, are all lliat can be desired. The illustrations, too, are well selected, and for the most part satis- factory from an artistic ]ioint of view. At the conelnsion of the descriptive part of tho work, two pages are devoted to tho geographical distribution of animals. While there are many aspects in which it might bc amended with advantage, tlio work as a whole has undoubtedly many merits, and it is a marvel of cheapness. "TiiK Cuii.n : .V Study IN I'liK Evonri'KiN' OF Man.'' By A. P. Chamberlain, m.a., I'II.d. (Walter Scott.) Ilbistratecl. (is — Tlie sub-title appears to us to cx[)ress tho scope of tho contents of this book better than tho first two words. The child is described in many of its aspects, but more as a stage in the evolution of man than as a special problem. The book is thus more adapted to the point of view of the student of organic development than that of the kindergarten or other teacher interested in child-study. Broadly speaking, the mental stages through which a person jiasscs in the course of a lifetime' can be represented by similar stages in tho psychological develojnnent of a race. Man begins at the very bottom of the ladder, both as regards body and mind, and slowly crawls to maturity. Dr. Chamberlain traces this progress with particular reference to psychological characteristics, aud shows how it can be interpreted by the ]irinciples of evolution. 'J'he bock is full of material for reflection, and suggestive ideas, but it might have been condensed to half its present dimensions witliout losing any of its force. Much of tijc matter seems to have lieen included more because it was available than because it was relevant to the subject. A teacher of psychology was once defined by a child as " A man who tells us what everyone knows in language which nobody can understand," and to this we may add that many ]isychologists elucidate and classify results which are of little value, even when they are understood. Take, for instance, the drawings which are often described and illustrated as representing the ideas of children. Such sketches of course do not show the images the child wishes to ])ortray, but the movements of a hand as yet unable to trace the workings of the mind. A similar criticism may be apjilied to the answers which some psychologists are fond of obtaining from children, with the view of determining the course of mental development. However, Dr. Chamberlain d(!als with many other uiatters, and his book contains much that is interesting concerning normal and abnormal man, from childhood to old age. "Botany, an Ei.f.mkntaky Tkxt foh Schools." By L. II. Bailey. (New York : The Maemillan Company.) ' 19(11 1. Illustrated. — With a clearer understanding of tho imjiortance of scientific methods of elementary teaching, there has arisen a demand for elementary treatises which is far from being satisfied by the works with which, in many brandies of science, teachers liavc still to rest coutent. Wo have no hesitation in saying that Prof. Bailey's elegant and beautifully illustrated volume approaches nearer to onr ideas of what a school-liook of Botany should be tlian .any that we have hitherto met with. No one cloubts now that the beginner should approach tlie study of plants in the field and not in the laboratory, with hand and eye ra'her than by the aid of razor and microscope. That the author fully reaii.-es this lie makes clear in the preface : — " The. pujiil should come to tho study of plants and animals with little more than Ins natural and native powers. Study with the compound micioscopo is a speciali/.ation to be made when the pujiil has bad e.vperience and when his judgment and sense of relationships are trained." The plant is set forth as a living organism, and the pupil is led to study it where and as it grow.s. With this part of the subject the first twenty-five chapters ('2011 pp.) are concerned. If these chapters are read and illustrated in the field, they must impart that living interest in living plants which is essential if the study of Botany is to have that educational value which it ]iosses.ses when directed by a wi.so teacher. Five chapters arc devoted to a consideration of relationships between the plant and its physical and organic surroundings. The economics of plant societies, the groat biological interest of which is the out- come of recent research, are briefly and clearly considered. In 88 KNOWLEDGE. [Apkil 1, 1901. the last six chapters the intimate structure and the class! ficati in of plants are dealt with. One of the most remarkable features of the book is the abundance and excellence of the illustrations, many of which are quite unique in a work of this character. It may iierhaps be considered that the volume is over-illustr-ated. Copious representations of Nature in a school-book of B itany are not unlikely to supplant field observations, and thus prove themselves a snare rather than a blessing. We trust that this work is destined to become well known in this country, and therefore the more regret that its u'jef ulness is impaired by the use of popular (American) names of plants which are quite unintelligible to the British reader. The botanical names in brackets would have been of great assistance both to teachers and scholars. These and a few other minor defects do not seriously detract from the excellence of Prof. Bailey's work, which we have read with great pleasure, and can heartily recommend to those who seek a first-class school-book of Botany. .-.-■ BOOKS RECEIVED. Practical Organic Chemijifri/ for Advanced Studenis. By .Julius B. Cohen, PH.D. (Macmillan. ) Illustrated. 39.6(1. Eepnrt on the Census of Porto Pico, 1S99. (Washington : Govern- ment Printing OfBce.) The A B C of Di/namo Desii/n. Bv .Vlfred IT. .\vciT. (Dawbarn ctWard.) Iliustrat-d. I9. net. Model Boiler Making. By E. L. Pearce. (Dawbarn & Ward.) Illustrated. 6d. net. S'lrtor Pesartiis. Heroes and Hero-Worshiji. Past and Present. By Thomas CarUle. (Wa-d,Lock.) 2s. Researches on the Past and Present Mistorg of the Earth's Afmos here. By Dr. Thomas Lamb Pliipson. (Griffin & Co., Ltd.) 2s nd. The Child: Mi^ Nature and Nurture. By W. B Drummond, M.B., CM., ll.B.o.P.E. (The Temple Cjclopa;dic Primers) (Dent.) Is. net. First Aid to the Injured and Imlulance DHll. By H. Drinkwater, M.B. (The Temple CvcLip.'edic Priiiiers.) (Pent.^ ls.net The Complete Works of John Keats. Vol. IV. Edited by H. Button Forman. (Gowans & Gray.i Is. net. Whist Dialogues. t!y Major Jack Teuace. (Bruxelles: Imprimerie E Waj-nians.) An Enquirg concerning the Principles of Morals. By David Hume. Keg>in Paul » Is. 61. The Value of Scientific Training. By Prof. J. Logan Lobley, F.G.S., r.R.G.S. (CuMTfll.) The Structure and Inher-ent Motions of the Universe. By Edward Meyer. (Adelaide : A. & E. I ewis.) The Phuto-Miniature, Januarg, 1901. (Dawbarn & Wai'd.) Monthly. • d. J'uper Work. Bjr Eev. F. C. Lambert. M.*.. and Charles Godfrey Lel,aU'l, 1I..4.., F.R.s.i. iDawbarn & War I.) 6d net. Sfventeenth Annual Report of the Bureiu of American Ethnology to the Secretari/ of the Smithsonian fustitutton, 1S95~G. Part II. (Wa-hiuiton : Government Printing Office.) Catalogue of Chemical Apparatus, t^'c. (London : Gallentamp & Co., lid.) 2s. Thornton-Vickard Photographic Specialities. (Thornton-Pickard Manufacturing Co., Altrincham.) The Norwegian North, Po'ar Expedition, 1893-1806 — Scientific Besulis. Edited by Fridtjof Nansen. Vol. 11. (Longmans.) 30s.net. Urttcrs. [The Editors do not hold themselves responsible for the opinions or statements of correspondents.] SUNSET PHENOMENON. TO THE EDITORS OF KNOWLEDGE. SiR.s, — T think Mr. E. W Maunder, in liis note .Tppeurled to Mr. McDonald's letter on ihe above subject, treats the matter possibly a little too cursorily, in stating that the rays are rarely traced right across tl\e sky. In the dry uplands of South Africa, in the brilliant dry weather one gets in winter. I have uight after night observed these lovely pink streamers stretching rii;ht across the sky, and meeting at a point, opposite the sun's position ; and 1 have often speculated as to their origin. They would never be i|uite the same two evenings running; sometimes there would be several of these rays, well defined, all a beautiful pink, contrasting exquisitely with the pale blue of the twilight sky. Next evening there might perhaps be one huge tan-like one stretching laterally over many degrees of the sky, with one or two narrow ones. I quite admit that they are exactly analogous to the rays of the sun piercing an aperture in clouds, which cut off his direct light from the space surrounding the cylinder of atmosphere illuminated directly. Rut the difficulty always occurred to me. where were the clouds that produced the streamers or rays, because we knew for certain (in the Transvaal where I was then stationed) that in the winter season the whole sky, over an enormous tract of country, was abso- lutely free from cloud. Those who have lived in the country referred to will, I think, appreciate this question. I have dwelt on this topic before, in the columns of the English Mechanic, and observed I should like to see the subject treated seientifically. Query : At what distance should, clouds be situated from the observer to produce the effect of these pink streamers shortly after sunset ? Of course the exact time would have to be given, in order to ascertain the depression of the sun, at that time, below the horizon. Also, is it not possible that the rays might be caused by the sun's light passing over rautres of broken hills aud mountains which abound in South Africa? The valleys between mountains might admit the tangential rays of the sun, while the mountains would cut them off. I have hv me a water-colour sketch of the Magaliesburg Range taken from a spot a few miles distant from Pretoria. The horizon goes up and down, as peak and valley are define 1 in the clear blue distance, and the gorge where the Crocodile i^iver cuts through the range is sharply marked. Might not such irregularities in districts some- what beyond the terrestrial horizon be the, cause of the pink streamers ? In some cases this phonoraenon is no doubt due to clouds, for I find that when at sea, in the year 1885, I noticed a curious effect one evening just after sunset ; the left hand part of the sky (looking westwards) was ru Idy, while the right was a beautiful turquoise hue. This was umloubtedly only a form, or sp^-cial case of the pink streamers, but in this case mountains could nut be brought in as the cause, as we were at the time far from land; and clouds must have been the cause. In England one does not often see the streamers stretching across the sky, and meeting at the point opposite the sun. I seem to recollect only one occasion. They usually take the fonu of a fan, and are so repre- sented in landscapes ; sometimes radiating upwards and sometimes downward, the sun being generally supposed to be above the horizon at the time. This phenomenon is quite distinct from the " pink glows," when the uhole of the western sky is illuminated with a pink glow, verging through orange to cojipery red near the horizon.. This is due to either aqueous vapour or fine dust ilisseminated in the upper regions of the atmo- sphere under peculiar conditions. E. E. Markwick (Col.). Devonport, 10th March, 1901. " MRS. QUICKLY'S TABLE OF GREEN FIELDS." TO THE EDITORS OF KNOWLEDGE. Sirs, — Surely a " table of green fields " is the correct reading. Dame Quickly, whose mind could not soar above the most homely ideas, was thinking (or, rather, Shakespeare was thinking for her) of a map of a country parish, on which the size and positions of its several fields are marked — the map is called a " Terrier " from terra — and she meant that Falstaflt's nose was so wrinkled and indented with lines as for it to be com- AraiL 1, 1901. J KNOWLEDGE. 89 parable to such a map. The comparison occurs in at least two other phices in Shakespeare, «■.;/., Maria says of Mavolio (,Acl III.. Sc. 2), " He doth smile his face into more lines than are in the new map, with the augmentation of the Indies'": the same idc^ being presented in Henry IV., II., 5, 1, by "He shall laugh till his face be like a wet clokc ill laid up. " Again, in "' The Rape of Liicrece,'' "SW turus nwiiv Tlio faoe, tlmt ump wliii'h doep iiiipressiim beai's Of liard misfortuMO carved in it with tears." Also in Titus Audrouicus, it is said to the woc-begone Lavinia, " Thou map of woe !' and in another play we have '■ Thy face, the map of honour. " Shakespeare, like other writers, uses the word " table " in the sense of a surface on which something is painted or drawn, «. \ \ ^^ "■■^5 NOTES:-. Conducted by Harry F. Witeerbt, f.z.b., m.b.o.u. Early Appearance oi? the Dotterel in Yorkshire. — Two Dotterels {Eudromias vwrineJlns) were seen here on February 18th, and one a»ain on March 2nd. These are surely extraordinary early dates for this summer visitor, which does not usually reach us until towards the end of April.— Philip W. Loten, Easington, Yorkshire, March 6th, 1901. The Little Dusky Shearwater {Puffinws assiiv.ilis, Gould'i in Sussex. — At the meeting of the British Ornitho- logists' Club, held on February 13th, a eommunicatiou from Mr. Ruskin Butterfield on the occurrence of a Shearwater of this sjjecies in Sussex was read by Mr. Hartert. The bird was picked up in an e.xhausted condition on the beach near Bexhill during the hard gale from the W.S.W. on Decembei- 28111, 1900. Both Mr. Ernst Hartert and Mr. Howard Saunders have examined the bird, and proclaim it to be Piijfiinig asiiwilis. This species breeds on the islets of the Madeirau group, the Salvages, nearer to the Canaries, and also in the Caj)e Verde Islands. It is also found in the Aiistralian and New Zealand seas. This is but the third occurrence of the bird in the British Isles, which indeed are far from its normal haunts, and the visits of this bird to this country can only be put down to accident. Taini)/ Oii-l in Ireland [Irixh Nati'i-ali.if, March, 1901, p, 72), — Iq Knowledge for Febvuarv, IflOl, p. t3. a record of Ihc occurrence of April 1, 1901.] KNOWLEDGE. i| the Tawny On I in co. nowii, In-laiul, was refi'iToJ to, and it was thero ivmarkod tliat tho l>ii\i liail never before occurred in Ireland. It now appctti-s lliat a gentleman in June last procnivd nine Tannv Owls from tho >'e\v Forest and liberated them in co. Down. This satisfaetorilv explains the pivsencc of the biril whii'h was shot in tho cinmtv in November lait. It appeal's also that a number of Jays have b«en liberated in the same way. The pnietiec of introducing birds or animals foreign to a country and liberating them in that countrv cannot bo too strongly condemned. From a naturalists' point of view such an act is the deepest offence, and is likely to cause almost as much harm to science as the exterminalion of a species in a country. The movements and geographical distribution of birds and animals is a ditlicult enough subject as it is without the interfering agency of mankind. What will happen in Ireland through the act of this " gentleman who takes some interest in ornithology " ■ All the future records of Jays and Tawny Owls in the north of Ireland will be under suspicion, and the study of the geographical distribution of the species as far as this part of tho country is concerned will be at a standstill. Tha introducer, moreover, added to his offence by not informing naturalists of what he had done. Apart from this it would be of interest to know who broke the law in procuring these young birds from the New Forest. Winter occurrence of House Martin in Yorkshire {The Xafuralisf March, IPOI. p. 74).— Mr. T. H. Nelson observes that a House Martin appeared in front of " The t'lifl'e," Kedcar, on December the ]4th last, and was seen at intervals, Hying to and fro, until the 2l)th. of December. Although, of course, the majority of Martins have travelled south before December, a few individuals, genera ly young birds, are occasionally seen in December in mild seasons. The above, howerer, is an exceptionally late occurrence for so far north. All contributions to the column, either in the way of notes or photographs, should he forwarded to Habry F. Withebby, (i£ 1, Eliot Place, Blacklieath, Kent. PRE-HISTORIC MAN IN THE MEDITERRANEAN. CENTRAL By John H. Cooke, f.l.s., f.g.s., etc. It has long been a niatter of common belief that the south of Italy and the northern coast of Africa are the remnants of a land barrier which formerly divided the Mediterranean into two basins, and connected the con- tinents of Etuope and Africa. This barrier has existed from early geological times. The nucleus of the Alps and Apennines consists of Jurassic rocks, and prior to the subsidence that ushered in the Cretaceous or Chalk period, a ridge of these rocks extended above sea-level from the north of Italy, through Sicily as far south as the island of Galita off the coast of Tunis. During Miocene times the ridge formed a portion of the bed of an extensive ocean, and it was then enveloped with a series of limestones and clays of great thickness whose representatives may now be traced in Tunis, Malta, Sicily, Italy, and as far as the northernmost limits of the Vienna basin. The evidences which arc offered of the former existence of the central Mediter- ranean land bridge between the two continents show that during the latter part of the Miocene period the bed of the Mediterranean, together with a large area of southern Europe, were slowly elevated. In the Maltese islands are to be found extensive deposits of Globigerina limestones which were laid down in a sea whose depth varied from one thousand to three thousand fathoms ; and these deposits are overlain by a series of marls, clays, and coralline limestones, which were deposited in depths of from one hundred to ten fathoms. A similar sequence may be traced in Sicily, Italy, and Austria where the series are overlain, in their turn, by extensive deposits of pebbles, sand, and loess of Pliocene age. The Pliocene period was a time of great unrest for the central Mediterranean. It witnessed tho birth of Etna, and the re-emergenco of the land bridge between Europe and Africa. The submergence of western Europe and of the greater portion of the Mediterranean set in at its close, and, besides forming the islands of Malta and Sicily, it laid down the breccias and loess, whicli extend over such huge tracts from the Urals to the Pillars of Heracles. Proofs of these physical changes arc reflected in tiic sequence of the beds of the district, in tlic zoological contrasts and affinities of the fossils, and in the mingling of northern and southern forms of animal and ])lant life, fossil and recent, in the caves and superlicial deposits on either shore of the Mediterranean. The central Mediterranean barrier is now in part sub- merged, the only visible renuiants being Sicily, the Maltese islands, and a few islets off the African coast, but the depth of the submergence is not great, being least between Malta and Sicily, and greatest between Malta and the African coast. An elevation of this portion of the Mediterranean floor to a height of sixty fathoms would re-establish the old continental con- nection. The region offers a rich field of research to the geolo- gist, and its problems suggest many interesting questions to the antiquarian. Rude stone monuments, implements, burial places and other records of the existence of primi- tive man in the area are surprisingly numerous. VVithin the last twenty-five years attempts have been made to classify the relics that have been found, and to trace out the histories of the peoples who originated them. To a certain extent the work has been successful, but much still remains to be done in the direction of determining whence the people came and the part which the great land bridge between the two continents played in their migrations. Remains of the Neolithic or later Stone Age folk have been found in every part of Sicily. Some of the most interesting were e.xhumed by Palumbo from a crevice near Caltanisetta, and by Fiorini from the Mon- tagna Grande near Palermo. In 1890 a series of Neolithic caves was explored at Isnello in the province of Palermo. One cavern was nearly filled witli human bones : the remainder con- tained an abundance of ornaments, stone weapons, and the ashes of cave fires. A cave was discovered in 1891 at Catania, containing the remains of a fire, a col- lection of mammalian bones, several human jaws, and a number of flint implements. The origin of the flint offered some difficulty at first, as it was not then known to occur in any Sicilian forma- tion. During a journey through Sicily in 1893 I traced it to the limestone deposits in the Val di Noto, and in the ravines at Modica and Ragusa, where it occurs inter- stratified widi bands and concretionary masses of chert or phatanite in the Miocene rocks of the district. Pro- ceeding westward to Sardinia, numbers of artificial caves, formerly used by the primitive Sardinians as tombs and dwelling places, occur in the sides of the hills and valleys. These caves vary greatly in size and character in different parts of the island, but among the natives they are known by the one name, domes di gianas. They are always found in proximity to the megalithic nuraghi, but they antedate these ruins by long ages, and belong at least to the later Neolithic period. The Neolithic races made their first appearance on the Mediterranean shores at the close of tho Glacial, or so called Post-glacial period, and no evidences of an earlier existence either here or elsewhere have yet been forthcoming. Their predecessors, the Paleolithic folk, lived in southern 92 KNOWLEDGE. [Apkil 1, 1901. Europe during the later Pliocene aud early Pleistocene times, that is, at the period when the greater portion of northern Europe was enveloped in a iner de ylace. These people were driven south by the intense cold, and they settled at many points around the Mediter- ranean. It is an interesting fact that though the remains of the Neolithic races are so plentifully distributed over the central Mediterranean area, no evidences have yet been forthcoming to show that the Pnleoliths ever in- habited it. A jjrobable explanation of the absence of Paleolithic relics in the central Mediterranean region is afforded when the nature of the physical changes that occurred in the neighbourhood at the beginning of the Pleistocene period is taken into consideration. The Pliocene and Pleistocene depo.sits which envelop the lowlands and flank the highlands of southern France, Italy, Sicily, Malta and northern Africa, as well as the vast work of accretion which Etna has achieved during its compara- tively short existence, afford some idea of the nature and magnitude of the forces that have acted on the area. The birth of Etna at the close of the Pliocene period was followed by the breaching of the land barrier which connected Eiirope with Africa, and its gradual subsi- dence beneath the invading waters. The changes were slow and tentative, and not of the nature of a cataclysm. The animals and plants of the land barrier were cut oil from the mainland, and as their habitats gradually lessened in area so they died off, and left their remains to form the massive ossiferous agglomerates that now fill the caves, fissures, and ravines of Sicily and Malta. Of the man of this period nothing is known, but it is possible that he recognised the danger of the situation, and, migrating, so escaped the fate which befell the remainder of the animal life of the district. He dis- appeared as mysteriously as he came, and the dehaclv that finally swept the area aud divided the continents was such as to remove every vestige of the old life, and every evidence of his occupation. His Neolithic successor experienced quieter times, and dwelt under conditions that were favourable to the preservation of his remains. Sicily and Sardinia are not the only places in the central barrier that have furnished evidences of pre-historic races. The Maltese Islands have, of late years, been carefully explored, aud have added, if not an important at least an interesting quota to our knowledge of the subject. In the early sixties the late Admiral Spratt and the late Professor Leith Adams carried on a series of in- vestigations in the islands. The discovery of a stone weapon by Mr. J. Frere, f.r.s., in a garden at Villa Frere, near Valetta, attracted the attention of Adams, and for several years he gave special attention to the question of the occupation of the islands by pre-historic man. Professor Issol of Florence visited the islands in 1868, and, while superintending the excavation of a series of trenches in the Har Dalam cavern at Mai'sa Scirocco, he discovered, at a depth of four feet from the surface, the remains of a fire together with a collection of bvirnt mammalian bones and fragments of a coarse kind of pottery. It is to be regretted that for nearly a quarter of a century after the return of Issel to Italy no further steps were taken to follow up this discovery. In the years 1887 to 1894 it was my good fortune to make several additions to our knowledge of the extinct fauna of the district, and to discover further evidences bearing upon the history of the islands' early inhabitants. The more important discoveries were made in the Uiod Har Dalam, a ^orge which is situated on the eastern coast of Malta, and whose sides arc perforated with a series of caves and fissures. The largest of these caves, known as Har Dalam, is more than half filled with a series of stratified floor deposits consisting of alternating layers of loam, ossiferous agglomerate, clay, stalagmite and boulders. These layers ai-e arranged in two well- defined divisions, the lower of which is separated from the upper by a massive layer of stalagmitic conglomerate representing a period of time of considerable duration. In the lower division of the series was found a curious assemblage of jaws, tusks, teeth, and limb-bones of extinct elephants, hippopotami, bears, deer, wolves and giant dormice. In the upper occurred thousands of limb-bones, jaws, teeth, and antlers of deer, together with the remains of horses, dogs, ashes of domestic fires, frag- ments of a coarse kind of pottery, and the metacarpal bone of a human skeleton. These relics of the Maltese aborigines were found at several points in the cavern, but always at about the same liorizon and in the upper division of tlie deposits. The latter fact is significant, as it agrees with the results of similar researches in Sicily, where no evidences of man have yet been forth- coming from deposits that were contemporary with the now extinct Quarteruary mammalia. The different types of animals in the two divisions of the Har Dalam deposits, and the varying states of mineralization in which the remains occur, indicate that the divisions be- long to two distinct epochs, and that a lengthy period of time intervened between them. The reason of this must be sought for in the physical conditions under which the floor deposits of the cavern were l^id down, and by which the gorge was deepened to its present level. Probably no part of Europe has undergone such ex- tensive changes in its configuration in recent times as the area now under consideration. The instability of the Mediterranean floor has been many times demonstrated during the jjresent century, as for example the inundations along the Italian coast, the upheaval of the Adventure bank off Sicily, and the submarine vol- canic outbursts off Pantaleria in 1892. A few years ago there was a tendency among geo- logists to call in the aid of cataclysms and other sudden operations of nature to explain geological phenomena ; but of late the pendulum of geological thought has swung to the opposite extreme, and the doctrine of cataclysms has made way for that of the uniformitarian, who advo- cates the theory of slow progression as the effect of un- countable centuries of imperceptible movement. The area around Malta and Sicily affords abundant examples of both kinds of operations. The Har Dalam gorge, like most of the valleys and ravines of Sicily, JMalta, Gozo, and Tunis, is bounded by rugged and precipitous clifl's, whose sides offer abundant evidences of the action of marine and river agencies. ^[any of these gorges were probably initiated during the upheaval which the area underwent in early Pliocene times, and afterwards served as the main linqg of drain- age of the country. Their bottoms are frequently covered with boulder beds and breccias, and their sides are scored with smooth curvilinear groovings suggestive of the action of considerable bodies of running water. The Har Dalam gorge was then probably a tributary of the river whose bed may still be traced along the sea bottom for several miles to the south-cast of Malta. On the banks of this river the late Professor Leith Adams discovered the remains of freshwater turtles, swans, and other aquatic birds, together with immense quantities April 1, 1901.1 KNOWLEDGE. on of bones of olepliants and hippopotami. This remarkable fanna existed al a time when tlio JNIaltese area formed a portion of the great Mediterranean land bridge, and when the elimatic conditions of southern Kuroiio were very different to those that now endure. The present rainfall of the iMalt.ese! islands averages 17 inches, and it rarely exceeds 19 inches. The amount of water, therefore, that annually passes down the gorges to the sea has little or no erosive power, and is barely sutBcient to remove the thin integument of soil which covei-s the bottoms in the higher reaches. The question of the age of the Har Dalam cavern ancf its fossilifcrous contents opens up an interesting field for investigation. The depth of the gorge is about seventy feet, and the cavern is situated at a height of forty feet from the bottom. The limited hydrographical area of the gorge renders it impossible, whatever the rainfall might be, to fill the gorge to a height sufficient to fill the cavern. The upper series of floor deposits were therefore laid down at a time when the gorge was very much shallower than it is now. It is hardly possible to express the antiquity of these layers in terms of written history, for the estimation of time by the rates at which rocks are denuded and built up is dependent upon so many variable factors that such chronometers are at best uncertain and unreliable. The Phoenician temples, tombs, and water tanks which are found in this gorge, at a level lower than that of the Har Dalam cavern, indicate how little the forces of erosion have effected since the time when they were constructed, about- 3000 years ago. Recent researches in the Nile delta have shown that two separate cultures existed prior to the advent of the Egyptian dynasties and Pyramid builders, thus giving a continuous history of 8000 years for man in Egypt. The ruder stages that characterize the Paleolithic and Neo- lithic periods in Europe are wanting around the Nile, but this is explained by the fact that the alluvial deposits of the Nile basin are not much more than 8000 years old. Observations have shown that during the last 8000 years the rate of deposition of Nile alluvium has averaged about one yard in a thousand years. The borings indicate that the average maximum thick- ness of the Nile mud in the valleys is about eight yards, and this points to the conclusion that immediately prior to the time when the first layer of mud was formed, the rainfall was sufficient to fill the river valleys and prevent the "dejDosition of the alluvium. The configuration and general physical features of the Egyptian Uieds and the Maltese gorges have much in common. The elimatic condi tions of the two areas are now, and probably always have been, similar. It is, therefore, probable that the work of gorge erosion was contemporary. and that the depth and extent of the Har Dalam gorge difiter but little from what they were at the time when the great change in the climate set in. If it were possible to fix the exact time when the upper series of beds in this cavern was deposited, then the age of the stone implements and other relics of human industry which they contained would be deter- minable. It is not probable that this will ever be done. To do so it would be necessary to revert to a period when the streams that coursed down the gorge were of suffi- cient magnitude and power to rasp away the gi-eater portion of the forty feet of hard semi-crystalline limestone that once lay between the mouth of the cavern and the present bed of the gorge. The time occupied by the waters of the stream in the work of corrosion and erosion must be added, and this, as li.is .ilrcadv been pointed out. is an indeterminable factoi'. The evidences aft'ordetl by llic Siciliiiu caves and I lii' ossiferous loams of (he JIar Ualam cavern bring the solutions of the problem bearing on the migi-ation.s of ]ire-historic man in the central Mediterranean one step nearer. It is true the step is a short one, but the work of exploration proceeds apace, and the time will come when the gulf wiiich at present separates the domain of the antiquarian from that of the geologist will be bridged by discoveries that will clear away the mist of un- certainty with which the subject is at present obscured. Conducted by M, I. Cross. SuHST.MiK (JiNnr.NSKKS. — II is gratifying to observe the number of first-class substage conden.sers that are offered by manvifacturers, and it is a distinct indication of growing know- ledge and appreciation of good things on the part of workers. It was at one time an easy matter to make a choice when only two or three systems were available, but it is evidently present- ing some complexity now, and in response to correspondents enquiries we pro])Ose to give a few bints on the subject. The main features of a condenser are : (1) 7'//*? /irhroniallxiii, (2) (iphdKiliiini, (?,) iintr/n/fi/i>irovided the aplanalism were as well corrected, and this is freciuently the case. I^^xpcnse m.ay therefore be avoided without loss of efficiency in this respect. The solid illuminating cone that an objective will bear has been frequently discussed. It is generally stated that three-fourths the full ai)erture is the best, but it will be found that the majority of lenses will not bear more than two-thirds without deteriorating in performance ; there are some exceptional ones that will take more than a three-quarter coue, but this is not the rule, and a light filter is usually requii-ite. The potrpi-. — The magnifying ])Ower of the condenser should not exceed half that of the objective, less rather than more than half is always preferable. Many sy.stcms are .arranged to work satisfactorily with the front lens removed, and by this means high and low power effects are secured in one combination. S>::e nf field leii-^. — The reason for the popularity of the Abbe illuminator, with its glaring imperfections, is on account of its large field lens and the ease with which it can be worked. A high power condenser must of necessity have comparatively small lenses, and requires as great care in manipulating as the objective itself. The Abbe achromatic condenser was an attempt to maintain the easy working of the Abbe illutninator in a corrected form, but it is really too heavy and clumsy and restricts the movements of a met-hanical stage. The best con- den.sers have, as a rule, the largest field len.'es that can be advantageously fitted, but this point is deserving of special consideration when making a decision. Rerniamrnduiionn. — From the foregoing it will be possible, with given objectives and a maker's catalogue, to choose the most suitable condensers. If a man proposes to restrict himself to low and medium powers, not exceeding say J in., he can readily make a choice, and we would like to specifically mention 94 KNOWLEDGE. [Apbtl 1, 1901. the new condenser introduced liy !Mr. C. Baker, of '^44, High Holborn : in this a specially large field lens is provided; the ])OWer (Tsi°-) '^ exactly the right one for histologists and workers with medium power objectives, while the aplanatic aperture closely approaches -W. We have found it most effective in some work we have been doing recently, and great credit is due to the maker for its introduction. The worker who does not go beyond an aperture of 1-25 can do all that his lens will permit with a dry condenser having the nominal aperture of 1-0 and yielding an aplanatic cone of 90 as several of them do. If higher a])ertures are used, an oil immer- sion condenser is necessary. This advice has an appalling ^ound. but it is too little recognised that such systems can usually be worked dry, and will then give an aplanatic cone exceeding -B''. Such is the ca.se with Watson & Sons' holoscopic condenser. Again, the top lens can be removed and a condenser of low power secured. Oil immersion condensers are too little appreciated, and it will be found, if it is desired to work with medium and high powers, that the oil immersion system will serve every purpose and is practically a universal condenser. The QrEKETT Microscopical Club.— The practical work done by this Society, which was founded in the year ISfi.'i, is recognised as being of the first importance. The meetings are attended by the foremost microscopists of the day. The journal, which is published bi-annually, and gives reports of the papers read and the proceedings generally of the club, is always worthy of careful perusal, but the great charac- teristic feature of the club is the welcome it extends to the amateur microscopist and the means it affords for bringing the novice into touch with the sound principles of manipulation, working and collecting. On the first Friday in each month, a " Gossip' evening is held, at which specimens are exhibited by members and dis- cussed conversationally, the regular business meetings of the society taking place on the third Friday in each month. There is, in addition, a first-rate library, and cabinet containing 6000 slides, which are at the disposal of the members. "We have before us a list of the excursions for the forth- coming season. These take place principally on Saturday afternoons, and have for their object the collecting of material that will afford interesting studies microscopically. "Pond life " has always been a very strong subject with the club. Visits are cordially invited to the meetings, which are held at 20, Hanover Square. When it is stated that all these advantages are offered without entrance fee for the modest sum of 10s. per annum, it will be conceded that every microscopist ought to make a point of becoming a member, and so supporting, in a practical manner, a club which has in the past and will continue in the future to jiromote the best interests of every feature in microscopy. Communications on the subject of membership should be addressed to the Hon. Secretarv, G. C. Karop, Esq., m.r.c.s., 198, Holland Road, W^., or to the Hon. Editor, D. J. Scour- field, Esq., F.R.M.S., 03, Queen's Road, Leytonstone. We hope, as the season advances, to give short reports of the excursions of the Qnekett Club members, giving details of the material that is collected and the place where it is found. RiNOiNO Slides. —Many amateurs prepare and mount speci- mens remarkably well, but few manage to put the ring of cement on neatly. It requires practice certainly, but generally it is through using the cement in too thick a condition. Pro- fessional mounters have two bottles, one containing the cement, the other the solvent — generally turpentine or methylated spirits. The brush is first dipped in the solvent, then in the cement, and a thin coat is deposited on the slide as it is rotated on the turntable. Some build the ring up at once, others allow the first layer to drj- and then complete the process : if there is sufficient time available the latter is the better way, but each time a fresh brushful of cement is taken, it should be pre- ceded by a dip in the solvent. The cement can then be deposited with cleanness and regularity. Lectures. — We have been apjdied to by a small Natural History Society for a lecturer or demonstrator, who would give an evening of- practic.ll ex])lanation of the principles and working of the microscope and its appurtenances. We should be glad to know of one who would like to make himself useful in this way and to put him in communication with our correspondent. A fee would be paid if necessary. XoTES AND Qi-ERIES.— -I//-. A. H abb'j rcl . — The "chalk which yon have been cleaning for Foraminifera is probably a manufactured article and consequently would be useless. Lime- stone from a cliff would be sure to yield the material you required. If vou have not an opportunity of collecting this yourself, and will let me know, I shall be happy to send you a small quantity that would give you good results. Communications and enquiries on llicroscopical matters are cordially invited, and should be addressed to M. L CROSS, Knowledge Office. 326, Hiffh Holborn, W.C. ♦ NOTES ON COMETS AND METEORS. By W. F. Denntng, f.b.a.s. Comet 1898 Til. (CoDDnfGToy). — This object, like the comets of Barnard (1892 Y.) and Chase (1898 Till.), was discovered by photography, and it remained visible for a considerable time. The observations, which number more than 400 in the aggregate, have been rigorously discussed by Mr. C. J. Merfield, of Sydney, and he gives definitive eleir.cnts in Ast. Xach.. 3684-5. The oomet passed its perihelion on 1898, September 14th, 0442, and its orbit appeai-s to deviate very slightly from that of a parabola. The Discovert op Comets. — As far as is known there is at present nothing observable in the way of cometary objects. The small comet discovered by Giacobini in December last has now travelled beyond the range of our best telescopes, and the expected periodical comet of Brorsen has not yet be«n re-detected. But we shall probably not have long to wait for the discovery of new objects in this field, for March and .April have been usually more productive than the winter months in furnishing them. Xo doubt many comets elude observation altogether, as the search for them is subject to many irregularities, and is very far from being exhaustive. The fact thata proportion of the known comets were found at times when they were long past perihelion, aad were on the point of disappearance through increasing distance, warrants the inference that every year there are several small comets which visit our parts of space, and leave it without being sighted by those astronomers who make it their duty to search for these bodies. Some of the observers who have previously occupied themselves in this work have done exceedingly well, and established highly creditable records, but many additional hands are required to complete the thorough exploration of the sky month by month. FiBEBAit OF XovEMBEE 27th, 1900 — This object was seen at lib. 10m. by Prof. A. S. llerschcl at Slough, Mr. H. Parsons at Leicester, and Mr. J. T. L'herrymanat Plymouth. At the latter place the meteor appeared to be very binlliant and large, falling in a perpendicular direction from the Polar star. At Leicester the observer was startled by the passage of " a liquid mass of fire which illuminated the sty. and fell slowly in a dignified sweep towards the south-west by south. ' Several frasments broke away from the central mass during its flight. The radiant point of the meteor appears to have been at about 47° + 45". and its height 57 to 17 miles over the region of llfracombe. Its visible path extended over 40 miles, and its velocitv was about 18 miles per second. Prof. Herachel has also investigated the real path of this interesting object, and places the radiant at 50^ + 45i°. He finds the heights 50 to 15 miles, the length of path 35 miles, and velocity 16i miles per second. The radiant between a. nnd /J Persei is that of a well-known shower of slow meteors at the close of X'ovember and beginning of December, and we arc- fortunate t + 12h^. It fell low in the west, and was intercepted by the house roofs which formed the sensible horizon. The meteor imparted a strong white glare to the sky for a distance of about 10= around it, and it moved with moderite speed. The same object was seen at Clifton passing down the skyto the right of the Pleiades, from about 44° + 35° to 24= + 26°. "it was very brilliant, but after a flight enduring two seconds, it passed behind houses near the W. by X'. horizon. The probable radiant of the meteor was at 72' + 41=. near 1 Auriga?, and this is really the focus of a well-known shower between about February 5th and 15th. Its height was from 56 io 26 miles, and path about 36 miles over Pembrokeshirj". The..e results are only approximate, and it woiUd be useful to hear of other observations. FlEEBALl, OF Febbuaet 27Tn. 1901. — Mr. Alex. Spark, of. Aberdeen, reports an unusually brilliant meteor, at 8h. 4.Tm.. travelling iu a X.W. direction. The colour of the head was bluish white, and it left a trail of reddish sparks. The fireball was also seen by an observer at X"ew Deer. Aberdeen, at 8h. 53m., passing through Ursa Major, between tlie stars € and !;, and directed from between 0 and 92 Leonis. It remained in sight 10 seconds. At Lerwick, in the Shetland Isles, Mr. A. Cadenhead noted the meteor at 8h. 51m., and describes it as April 1, 1901. KNOWLEDGE. 05 travelliiis; thivugli Ouu-or ami Caiiis Minor, mul ili-iiijiiiwii-ing iu llu- Tioiiiitv of Orion. Thi> lu'iglit of tlio olijrct wns froiM about. lOii iniles oviT tlic Xortli Soa to 57 niilos over Stroiisa, Orknoy Islos, ami its lengtli of )wth about 12t) inilvs. '1 he radiant point was at ahoni ICo"" + li\ so the ini'toor was one of the r Leonids which form a very .ii'tivo >hower durinj tlie first few nights of J[areh. Large ni>-teor» are aNo reported as observed on the nijht of Febrnary 18th. ou KeVuarv 20th at ll.i.") |i.ni.. and on .Marcli o'lh at 7.20 p.m., but very few< descrijnions liave eomo to liand. Reports conic from America tiiat on Friday afternoon. December 7tli, 1900. a brilliant fireball, rivalling the sun in the iutcusity of its light, passed above Colorado and Wyoming, frightening horses and cattle, and giving n loud detonaiion. Tub Armi. Ltrids. — This periodical shower will recur under favourable eireumstauces in lilOl. ti»e moon being new on April IStli. so that observations may be mide between about .Vpril lotb iiml 2.5th. This system rarely furnishes a conspicuous display, but it is very interesting from its connection with Comet I., IStil. The radiant of the shower is at 271" + 3S^ between Hercules and Lyra, and this point proliiibly shifts somewhat rapidly to thn eastward. Observations should be specially made to elucidate this feature. Tlie immediate region of the radiant sliould be watclietl for long periods on several night* before and after the maximum (April 20tli),and the exact place of radiation should be determined separately for eacli night. THE FACE OF THE SKY FOR APRIL. By A. Fowler, f.r.a.s. The Srx. — On the 1st tbe sun rises at 5.38 a.m., and sets at 6.30 p.m ; ou the 30th he rises at 4.37 a.m , and sets at 7.17 p.m. Sunspots are not likely to be eithei" large or numerous. The Moon'. — The moon will ho full on the Ith at 1.20 A.M.. will enter list quarter ou the 12th at 3. ,57 a.m., will be new ou the 18th at 9.37 p.m., and will enter first quarter on the S.Sth at 4.15 p.m. The following are among the oecultations which occur during the month : — 6 I 3 I a o . a Apr. 4 „ 8 .. 8 22 B.A.C. 4531 u' Scorpii ... 0.' ., X' Orionis ,. 19 Sextantis b-7 41 5!> 60 U..iO P.M. :S..=>9i.a. 45 A.M. 10.25 P.M. 7.40 p.m. 97 81 10 71 168 104 71 5 32 170 1.18 5,19 • 4.20 nil S.31 1 28S 366 305 2t7 304 267 .342 269 2.3S d. h. IS 11 1815 18 15 4 1 [On May 3rd there will be a penumbral eclipse of the moon, from 4.6 p.m. to 8.55 p.m. As the moon does not rise until 7. 28 p.m., the eclipse is only partly visible at Greenwich.] The Planets. — Mercury is at greatest westerly elonga- tion of 27^ 48' on the 4th. and is a morning star throughout the mouth. He is not well placed for observation iu our latitudes. Venus is nominally a morning star, but is too near the sun for observation. She will be in superior con- i unction at the end. of the month. Mars remains in Leo and may be observed throughout most of the night, setting on the' 30th at 2.45 a.m. At the middle of the month he crosses the meridian at 8.15 P.M., and the illuminated part of the disc is 0924. The apparent diameter diminishes from ll"-4 to 9"0 during the month. Jupiter is a morning star, iu Sagittarius, rising on the 1st at 2.19 A..M., and on the 30th at 12 29 a.m. He is in quadrature with the sun ou the morning of the 2nd, and stationary on the 30th. Saturn is also in Sagittarius, a little to the east of Jupiter. He rises on the 1st at 2.32 A.iM.,and on the 30th at 12.40 A.M. He is in quadrature with the .sun on the Gth, and stationary On the 26th. Uranus is in the most soutlierly [)art of Ophiuchus, 4'' to the north-west of 0 nbout the middle of the moiilli. The planet rises on the Isr at 12.31 a.m.. iiiul ou the oOth at 10.35 P.M. Neptune remains in the most easterly l>art of Taurtis setting on the 1st soon after 1 a.m., ;iud on the 31st soon after 11 V.m. During tlie mouth he describes a short eastcrlv path almost midwav between y' Orionis and 132 Tauri TitE Stars. — About 9 p.m., at the middle of the month Leo will be on the meridian ; Gemini iu the south-west ; Orion in the west ; Virgo iu the south-east ; Hercules in the north-east, and Ursa Major almost overhead. Minima of Algol will occur on the 2ud at 8.23 p.m., and on the 22nd at 10.6 p.m. C!)css Column. By C. D. LococK, b.a. Communications for this column should be addressed to C. D. LococK, Netherfield, Camberley, and be posted by the lOth of each month. Solutions of March Problems. (C. D. Lococli.) No. 1. I. Q to Bl, and mates next move. No. 2. 1. R (R3) to Rsq. No. 3. 1. BxQP. [This has been rather ambiguouslv desi-ribed as " a talcing key." The P at R6 was left on the board liy mistake. In a former version of the problem' it was necessary to prevent a solution by 1. R, to Q7cli, and 2. Q to R6.] C, L. Massey.--T can find no trace of any statement in Knowled'IE to the effect that problems known to have more than one key would not be printed. While agreeing with you that the seaich for a second key is generally profitless, and sometimes vexatious, 1 may, perhaps, jioint out that such search often disckises the hidden art. of the coiupo.ser in avoiding " cooks," which might otherwise have escaped the solver's notice. But the prin<'i])al reason for allowing an extra jioint for a second sohition lies in the fact that, without some such device for 'oto by E. Walter Maindeb . lOS TaE Nedflae Hvpothesis. By Geo. McKenzie Knight lO'.i The Xebclae Hypothesis. By William Xoble. Note by Eds " 109 Constellation Studies. By Eenest L. Beilby. Xote by Eds ... . lo9 Notices of Books . 110 Books Keceiyed 112 Notes ... 112 The Insects of the Sea.— 111. Beetles. By Geo. II. Carpenter. b.bc.(lond.) (Illustrated) ... ... ... Ill British Ornithological Notes. Conducted by IIabkt F. WiTHEP.BY, F.Z S.. M.B.O.U. ... ... ... ... ... 116 Microscopy. Conducted by M. I. Cross. 117 Notes on Comets and Meteors. By W. F. Denning, F.R.A.S. . ... ' ... lis The Face of the Sky for May. By A. Fowler, f.e.a.s. ... 119 Chess Column. By C. D. Lococe, b.a 119 THE SIZE OF OCEAN WAVES.-III. By Vaughan Coenish, ji.sc.(vict.), f.c.s., f.r.g.s., Associale of the, Owens College. Ix a previous article I gave the results of Admiral Cpupvent des Bois' attempt to connect the average height of the waves with the strength of the wind. The Table VI. embodying this result was the outcome of about 7000 observations made on board the Astrolabe. More recently Captain D. Wilson-Barker, H.M.S. Worcester, has published* a table showing the connection between wind and wave according to his own experience. This extends over many years at sea, during wliicli he was nine times round tlio world in sailing ships in liigh southeni latitudes, and made many measurements of waves combined with simul- tc-ineous observations on the strcoigth of the wind. TAin,K VII. Wind velocitv and corresponding soa disturbancp (!). Wilson-Biirkrr). Beaufort Scale. Oescriptiou of Winil. Velocity in Miles per 11. .nr. Sea Distur- liauco. Heislit of Waves ill Feet. Desor!t>tion nf Shu. 0 Calm 0 0 0 Calm 1 Light airs .•i 1 0^1 Very .smooth ^ Light breeze . 9 •J 12 Sniootli :i IModenitc breeze 16 :! 2 3 Slight \ Fve.fh breeze ... 21- 1 3 5 Modernte r. Strong breeze ... 34 .'> (!-10 Rather rough H Crale : -is (1 ID-IH Rough 1 Strong gale 1 :,-> i 18-28 High 8 Hurricane 1 70 s 28 Tremendous The tables of Paris, Coupvciit des Bois, and Wilson- Barker ai'e not perfectly comparable throughout, but I think we may venture to arrange in parallel columns the four greatest values for average height of waves, and to assume provisionally that they represent three independent sets of obsci-vations of average height of waves in deep water and open sea, during strong breeze, gale, strong gale, and a gale of hurricane force. Table VIII. HoiLi'lit (if Wuves in feet. C. lies Bois. Pnris. Wilsoii-Hnrk(;r, Hurricane Strong gale Gule ... Strong bi'eeze 28-54 20-67 15-42 Io-k:! 25-43 16-.'J7 28 •J3 14 • Quarterly Jcmrnal of fheSoyal Meteorological Socieit/, V0I.XX.Y., Xo. 109, .Tanuary, 1890, p. 15. With regard to the lengtli of waves, I think most observers will agree that the greatest average length of wave is not observed where the wind is blowing strongly' but where the sea is heaving with a steady swell in a comparatively calm atmosphere. Thus in Lieut. Paris' record the maximum average wave length for a single day (771 feet) occurs when the state of the sea is described as (/ro-txe houle. a heavy swell, whereas the greatest average length ,for a day of storm (trea- grosse mer) was 590i feet. As the average force of the wind for " trcs-grosse mer " was indicated by the number 9, and that for " grosse houle " by the number 5 (on a scale of 0-11), the above appears to be the neces- sary interpretation of Paris' figures. In this matter, however, we are fortunately able to adduce other evidence besides the observations made from ships at sea. Observations of the intervals of time between the breaking of the waves on shore are easily made, the intervals of time are greater for the larger waves, and the longer intervals are those recorded during " ground- swells " in calm or comparatively calm weather. Thus on December 29th, 1898, in the fine weather with north- westerly breeze following a great storm accompanying an atmospheric depression which had travelled quite across the Atlantic, I obsei-ved at Branksome Chine near Bournemouth, an uninterrupted scries of 139 98 KNOWLEDGE. [May, 1901. ° iS ^ t> -^ K breakers. The average interval between succeeding breakers was 19.35 seconds, from which it follows that the average wave length in dijep water must have been 1918 feet. This is calculated from the formula Length of wave in deep water in feet = square of tlie period in seconds x 5'123. This formula is derived theoretically from the known behaviour of liquids imder the action of gravity, and has been verified to some extent by observation. Its substantial accuracy when applied to a swell of no great steepness travelling in a fairly calm atmosphere is, I believe, beyond question. The corresponding velocity of the wave is 68.7 statute miles per hour in deep water, which is slightly less than the velocity assigned by Capt. Wilson-Barker to a storm of hurricane force. Sir George Gabriel Stokes has observed breakers with a uniform period of 17 seconds; and I find that a period of 15 seconds is not uncommon with westerly swells on the south coast of England. A 15 second period corresponds to a wave length in deep water of 1153 feet. Thus the average interval between the wave crests observed during a storm at sea seldom ex- ceeds 600 feet, although the period of breakers frequently indicates a wave length twice as great. I do not know whether attention has been drawn to this anomaly, and I have not met with any published facts which explain it. I propose the following ex- planation : — The swell frequently arrives before the storm ; subsequently when the wind gets up the sea becomes covered with short steep waves ; these grow in length, and gradually the swell be- comes less conspicuous, until at last it is nearly or quite invisible in presence of the storm waves (say be- tween 300 and 600 feet in wavel length). The natural inference would be that the amplitude of the swell must be small as compared with that of the storm wave. This, however, is not necessarily the case, as an examina^ tion of the diagram will show. In looking at this it must be remembered that when waves are observed at sea we have not a fixed platform to observe from, nor can their profile be traced against any fixed structure. The ship rises and falls with the long swell, and the observer has very little notion where the line of mean sea level is ; and for this reason I have not drawn any datum line in the diagram. What he does notice is whether the water siu'face at any place is convex or concave, and, more particularly he notices the advance of the convexities of crests, f Now it is obvious that even though the long swell have an ampli- tude equal to that of the shorter storm wave yet its curvature is less, and therefore it is less potent than the latter in detei'mining the positions of crests, i.e., marked convexities of surface. To assume that during storms there is a long swell (say not less than 1100 feet) of an amplitude equal to that of the storm wave would, however, be going somewhat beyond what the facts seem to warrant, but that such invisible swells may have a considerable amplitude seems to me quite possible from what we know of the swell remaining after a storm, of the distances which these swells traverse, and of the size of the breakers which they yield, and finally of the variation of the amplitude of successive waves in a storm. Fig. 1 shows a portion of the actual wave surface due to the simul- taneous existence of two undulations with length 600 feet, amplitude 30 feet, and length 1150 feet, ampli- tvide 20 feet. Commencing on the left with the two undidations at the same phase, at mean sea level, and subsiding, there arc shown in the figure five t The curvature at the cres); being sharper than in the troughs, a ditTereuce which. howeviM". T have not shown in the ilingrani. M.A 1901.] KNOWLEDGE. 99 crests of the 600 feet undulation and throe crests of the 1150 feet undulation. The resulting wave surface of the sea in this case would at any one moment show a series of ridges and hollows differing from one another in wave length and amplitude. This series would be followed by other scries, identical with it. The third (lowest) line of the diagram is a portion of a series. It contains five wave crests, i.e.. the same number as the shorter constituent wave contains. Measiu-ing from the diagram I find that, reckoning from the left, the succeeding waves have — Amplitude 38'85 feet. Length 575 feet. Lengtli 62') feet. Amplitude 27'5 feet. .Vmplitude 30 feet. Length .575 feet Length 62.") feet. Amplitude 27o feet. Amplitude 35 feet. The average wave length is 600 feet, precisely that of the shorter constituent, the average amplitude is 29.77 feet, which is (within the errors of measurement) identical with the amplitude of the same wave. The record of measurement of waves in such a sea as usually published, that is to say, giving the average dimensions of a series of waves, would give no indication of the existence of the long swell. It would perhaps be just visible if the light were good as something running faster than the waves, not unlike the shadow of a passing cloud upon the water, but I think its magni- tude would be much under-estimated. This swell does not greatly afiFect the amount of surface disturbance, though it renders it more iiTegular ; but at a depth where the effect of the 600 foot wave is no longer felt the heave of the 11.50 foot swell is still strong. Thus, although the existence of the long swell may be barely discernible by the eye in a storm, and although the recorded (average) wave measurement may not reveal Its presence, yet the sea is really in a very different state when such a swell is running from what it would be if affected only by the recorded wave of 600 foot length and 30 foot amplitiide. In drawing figures in which the amplitude of the swell is made equal to that of the storm wave I do not intend to assert that this is the usual condition ; the intention is rather to show how even a great swell is masked by the shorter wave. I am trying in these articles to tell what is known about the size of ocean waves, and how that knowledge has been obtained. I have now reached the point, to which one comes sooner or later in almost eve'.-y enquiry, when it is advisable to look more closely into the mean- ing of the word which designates the thing investigated. For research in natural phenomena I prefer this plan to that of beginning with a definition. We find the sur- face of the sea covered with a series of ridges and furrows which are not uniform on the one hand, but have on the other hand only a moderate range of size. There are of course wavelets also present, but these are easily distinguished from the greater waves which we want to measure. The difference in size between succeeding ridges seems to be mainly due to the existence of two or more sets o£ undulations each of which may be regular. An illustration of this may bp obtained by watching one wave crest as it advances. The changes of form which it undergoes are readily understood on the supposition that one billow is catching up and passing another. These changes are the same as those shown in the figures in passing from crest to crest of the combined wave. Xow if we want to know the size of ocean waves it is evident that we must make up our minds whether we mean the size of the ridges and furrows which at the time actually constitute the surface of the ocean, or, on the other hand, the sizc^ of the constituent undula- tions the superposition of which constitutes those ridges and furrows. The actual ridge or mound of water is not only the chief visible phenomenon but it is also a tangible, often a terrible reality, which the sailor calls " a sea.' On the other hand the constituent undulations are what chiefly receive the attention of the theoretical man, and they have in some respects a greater individuality than the " seas," for they retain each their length and speed, and, sorting themselves as they travel beyond the storm area, they partition out the ocean among them, the longest and swiftest coming to the front, the slower and shoi'ter lagging behind. In the systematic records of the size of ocean waves, writers have generally attempted to follow the pro- cedure of the theoretical man in this matter. Thus Monsieur Bertin, in his excellent Memoir oti the E.rperimental Study of Waves.l says, " We are certain in adopting 16 metres (52i feet) as the maximum limit of height to have got beyond all the observed values. I must further remark that I only speak of waves in the open sea, and of those belonging to a single swell. An isolated rock 25 or 30 metres (82 to 98 feet) high may be covered by a breaking sea. Waves belonging to different systems of swell may ride one over the other, giving rise to topping seas without speed, and with a short period, or to any other irregular and exceptional agitation " In December, 1900, I crossed from Liverpool to Boston in ss. Ivernia, and heavy weather was met with. Quoting from the report sent in to the U. S. Hydrographic Office, we had on December 6th strong westerly winds with high sea; December 7th, strong squally wind, increasing to strong gale, with heavy regular sea; December 8th, strong gale, S.W., W., N.W. ; December 9th, X.W. wind, moderate to force 6, and backing W.S.W., increasing to force 8 ; December 10th, fresh gale, with frequent squalls, wind hauling to N.X.E. and X.E., short high sea; December 11th, wind west, having hauled S. to S.S.W., increasing with hard snow squalls and falling thermometer, short high sea ; December 12th, moderate gale to moderate breeze at mid- night; December 13th, wind force 6-7, with occasional snow squalls, sea rough. I paid particular attention to the question of the height of the waves, and tried to consider the matter without bias. It seemed to me quite as important to know the height of the larger seas occurring from time to time as the average height of the waves. Thus the average height of the waves on December 8th was less than the elevation of the lower deck, but the lower deck on the weather side was unsafe on account of the occasional big " seas," of which I mea- sured one or two of 40 feet or upwards. It is these larger seas which rivet the attention, and remain in the recollection of a spectator. I do not think anyone could fairly be blamed for saying that on this occasion the ship met with waves about 40 feet high, for they were not seen only once but many times, yet, as well as I could guess, the averacje height of the waves was not more than 20-25 feet. I think it probable that when we hear from sea- men that they have known the waves in a storm 40 feet, or it may be 50 or 60 feet, in height, we must interpret t Institution of Naval Arfhitects. April, 1873. 100 KNOWLEDGE. [May, 1001. the statement to mean that this is the measnre, oi- estimate, of the average height of the greater waves of which some were encountered and a number seen during the storm, and I see no reason to quarrel with such a mode of statement. It admits, liowever, of an apparent discrepancy of probably 100 per cent, between the values assigned to the height of ocean waves accord- ing to whether we adopt the concrete or the abstract notion of a wave. GIANT OSTRACODA: OLD AND NEW. By the Rev. Thomas R. R. Stebbing, m.a., f.r.s., f.l.s., etc. As students ai-e aware the species of Entomostraca are for the most part very inconspicuously conspicuous, and among those of them which are thus notable not for being very large but for being very little the Ostracoda, if not absolutely foremost, are certainly well to the front. Recent researches, however, have shown .that in this group as in othei's an astonishing disparity of size may separate exceptional members of it not only from the minutest fomis but from the average dimensions. In 1880, Dr. G. S. Brady in the first volume of the " Challenger " Zoological Reports described a new genus and species from the South Pacific under the name Crossophorus imjyerafor. After giving the length as " ^ of an inch (8.4 mm.)," he refers to it with a kind of ejithusiasm as '" this noble species, certainly the largest of the known Cypridinidas." The family in question was already itself distinguished among the Ostracoda by having representatives which could boast of some such exorbitant length as the sixth of an inch. By abruptly doubling this the Crossophori/.s would pro- bably attain a bulk about eight times that of its largest known competitor. In 1896 Drs. Brady and Norman described another specimen, assigned to the same species, with a length of 7 mm. Though both specimens were reported from very great depths of nearly equal tem- perature, it is remarkable that the first, a male, was taken a little to the east of New Zealand, the second, a female, " was procured by the ' Porcupine ' Expedition of 1869, in the Atlantic, west of Donegal Bay, Ireland." The same length of 7 mm. is reached by CijrlaMerope Jieiuleraoni, Brady, 1897, which Mr. Henderson, of the Christian .College, Madras, brought to light by dredging in Madras Harbour. At the close of last year a new species, Asferope artbiiri, 8 mm. long, was described among the Crustacea brought by Dr. Arthur Willey from the South Seas. In regard to this interesting form it may be mentioned that before the specific name had been given, some of its appendages were figured in the volume of Know- ledge for 1899, in the course of an essay dealing with the general structure of the Ostracoda (Vol XXII p. 31). In 1898 Professor Sars described a new genus and species under the title " Mec/nlocyprif; 2irmceps, a gigantic fresh-water Ostracod from South Africa." This species, from a pond near Capo Town, attains a length of 7.30 mm., while apparently not full grown, and,'' as it belongs to the family Cyprididae, in which the forms are usually very small, its " truly gigantic size " is even more surprising than that noted in the preceding instances. In 1900 M. Jules Richard reports a " Gujanto- <-ypri«" a\w\ii lo mm. in diameter, as having been dredged by the Prince of Monaco from a great depth off the Azores. These examples, however, do not exhaust the po.=si- bilities of the Ostracode group, for Dr. Gilchrist in December, 1899, while conducting marine investigations on board the South African Government vessel the " Peter Faure," and dredging in 90-100 fathoms off Ca2)e St. Blaize, obtained specimens of Ostracoda which much surpass the dimensions above quoted. The speci- mens were speedily forwarded to me by Dr. Gilchrist, and were examined at once. That they have not been sooner recorded is due in part to the well-founded and growing dislike of preliminary notices, and in part to my apprehension that there had been made else- where an earlier discovery of a magnificent Ostracode, which might prove to be the same species. After talking the matter over with a scientific friend, I am now induced to think with him that tlie case is one of exceptional interest, in regard to which publication should no longer be delayed. The fact is that the speci- mens have a length of 15.5 mm. by a height of 12.5 mm., so that the noble Croxsoplwrus imperatiir and the truly gigantic Meijahicyprin princep^ are positively dwarfed by the comparison. The new species, for which I jjropose the name Crosso- phorus africanus, has its generic position pretty well assured, since, among other points, to quote Brady and Norman, " the peculiar arrangement of the armature of the caudal laminae is unlike that of any other known genus." But the new species, though agreeing in the general plan of arrangement, differs in detail, having only five principal spines instead of the seven which the smaller species displays. The mandibles have the bifid masticatory appendage, found in one or two other genera, but not there densely setulose as it is here. The maxillipeds have the large sub- triangular lamina, fringed with plumose setae, and ending with a small lobe also fringed. This lobe is peculiar to Crossophorus, but it is much less clearly developed in the Irish speci- men of C. imperator than in the New Zealand specimen. From the Irish C. imperafor the new African species is strikingly distinguished by the apical part of the vermiform limb.* Here it forms a regular mouth, one jaw ending in a tooth, which confronts in the other a neat circlet of denticles. In the Irish specimen the tooth confronts ''several (six?) finger-like curved pro- cesses which are ciliated on the edges." In the New Zealand specimen the limb is described as being " al- most exactly like that of Cypridina." The result of these comiaarisons is to make me believe that we have to do with three specimens of the genus, first, the original Crossophorus imperator, Brady, from the Pacific ; secondly, the species described by Brady and Norman, of nearly the same size, from the North Atlantic, which may be distinguished as Crossophorus imperialis ; and thirdly, the new African species, Crossophorus africanus. For the latter detailed draw- ings have been already prepared, and these with accom- panying description will, I hope, in due time more fully explain, and adequately justify this preliminary decision. That an iso]jod which I find parasitic within the new species is itself likewise new may be affirmed without hesitation. The name I propose for this is CijproniscKs crossophori. It bears a strong resemblance to the much smaller Cyproin'scns cypridimr, Sars. Its distinctness will be apparent in the account and figures which are reserved for their a]ipropriate ]ilace in the " Marine Investigations of South Africa," published by the Cape Government. * For the general appearance of this strange appendage, see the figures in Knowledqh, Yol. \XIT., pp. HO, 31. May, I'JOl.] KNOWLEDGE. 101 THE STRONGHOLD OF THE NUTHATCH. A STORY OF SIEGE AND DEFENCE. By A. II. Machell Co.x. m.a. Picture a sleepy old rectory garden — a very paradise of birds — merging iiito a little rambling spinney, and lyiug so elose beneath its shelter that the gradual, al- most imperceptible transition only serves to enhance the sweet smell of the woodland. Here and there a line old oak breaks the stiffness of surrounding ever- greens. One such tree is so persistantly visited all the year round by a pair of nuthatches as to arouse in- the practised birds-nestor a suspicion which a closer scrutiny proves to be well founded. At a height of rather more than thirty feet from the ground is a hole, clearly enough the socket of a branch long since defunct, and only arresting attention by its unnaturally smooth and rounded appeai-ance. For such an eligible building site as this there must have been at one time applicants in plenty among the various birds that seek a habitation in ready-made cavities, but in thci end our nuthatches evidently obt-ained the premises on a long lease, and for many a year (with one notable exception, to which I shall presently refer) their tenancy has remained un- disputed. Nor is the reason far to seek. Against birds no larger than itself, the sturdily built nuthatch, with its strong foniiidable bill, is perfectly capable of holding its own. while against more determined aggres- sors like starlings it adopts the ingenious precaution of plastering up the entrance to its home with mud, and reducing it to such a size as will exactly meet its own requirements. This is a well-known peculiarity; that it forms an invariable feature of the household arrange- ment cannot indeed be positively asserted, but from all accounts the exceptions to the rule must be very few indeed. Similarly it is recorded that before a nuthatch can be induced to take possession of a nesting box in a garden, its habitual cuteness leads it to detect the lid opening on a hinge, so fatal to privacy, a drawback which it will at once proceed to remedy by a plentiful application of clay. So skilfully is the work done in the first instance, that when the nesting season comes round again, only slight repairs and alterations are required ; but these receive the most scrupulous attention, and even in the depth of winter an occasional inspection is made, and these all important defences overhauled. I do not recollect ever having seen the male nuthatch assist his mate in any of the actual work. but he is invariably somewhere at hand in close attend- ance, and ever reaxly in the spring to serenade her with his cheery long-drawn' \vhistle ; in the winter he is per- haps apt to be self-assertive, but during the time of courtship I have watched him offering, with an air of the greatest gallantry, choice morsels of food to his mis- tress. Immunity from danger had, as I have said, been long enjoyed by this particular pair, and it was with some compunction that I yielded at last to my instincts as a birds-nestcr, and resolved to exact the toll that seemed so ready to my hand. Had I indeed anticipated that any disastrous consequences might attend my raid I should certainly have abandoned the idea ; but I argued from what I knew of their general disposition that there would be little likelihood of their homo being deserted for any cause short of deliberate eviction. Accordingly at the time when I calculated that the eggs should have been laid, I secured a ladder (without the aid of which the hole was iuacccs-sihlo), and armctl with chisel and haiuiner ascended to cniiiniit the burglary. My intention was to enlarge the entrance sufficiently to enable me to insert a hand and investigate the interior ; but I soon found that I had under-rated the difficulty of such a task. The wood was extraordinarily hard, and the mud defences themselves could hardly have been removed without tools; moreover the distracted owners, taking up positions within a few yards of me, never ceased to protest loudly and vigorously, and altogether showed such keen distress that I was more than once half inclined to desist. When, after two hours' hard work, the nest was brought within reach and proved to be empty, it almost seemed like a judgment on perse- cution. It only remained for me (o do all in my power to repair the damage done, and some wet clay soon en.abled me to reduce the hole to its original dimensions. Hardly had I descended to the ground when a blue tit appeared on the scene, and, perching for a moment on a rung of the ladder poked his head into the hole with characteristic curiosity. A few moments later, to my great satisfaction, I witnessed the return of the right- ful occupants, who without further ado proceeded to complete my amateur work as a plasterer. So ended the first act of the drama; reference to my notebook shows that the date was April 17th. For just a week the nest was left undisturbed, and then I made a second investigation. During the respite the rude clay had by some mysterious process, the secret of which the nuthatch seems to share with swallows and house martins, been hardened to the consistency of cement, the whole surface having been so scored all over by countless indentations of their beaks that it pre- sented the appearance of elaborate stucco work. This time it was only the work of a minute to make a breach, and the results though not altogether successful, were on the whole satisfactory. A single egg was discovered in the nest ; this I carefully replaced and a fresh supply of clay was utilized for the needful repairs. Once more the birds returned undaunted. Xow a fresh complication arose which quite altered the aspect of affairs. The next morning I was approach- ing the tree quietly to see how things were going on, when I caught sight of a bird, which proved to be a starling, busily pecking away at the entrance to the hole. The fact was that all the starlings in the neigh- bourhood were just then turning their thoughts to the business of nesting, and the sharp eyes of one pair had already discovered that this hitherto impregnable position had been tampered with, and that the clay while still damp and soft presented no insuperable barrier. Possibly they had witnessed the whole pro- ceedings of the previous day and laid their plans accordingly. However that might be, I determined to defeat their object. Fetching my gun I cautiously stationed myself in hiding among the bushes beneath. I had not long to wait. A starling settled noisily on the top branch and was at once joined by another. There they commanded the situation, and their purpose was unmistakable; as I wished, however, to catch them in piqrante. delicto I still awaited developments. Presently first one and then the other nuthatch returned for a moment to the tree, but scenting danger Hew off again uneasily. An interval ensued during which the conspirators (myself included) remained motionless at their several posts, and then the female came back with a large bit of clay in her beak, and after flying round the tree once or twice alighted on the trunk on 102 KNOWLEDGE. [May, 1901. the side sheltered from the view of the starlings. Gliding quickly down she suddenly slipped round to the hole, and was beginning hastily to attend to repairs, when one of the starlings with a harsh chattering noise swooped viciously down upon her. In less time than it takes to write the other nuthatch had come to the rescue, only to find the attack reinforced by the second starling. Taken at a disadvantage the nuthatches had to beat a retreat, and the original starling — the prin- cipal aggressor — stood screaming triumphantly at the mouth of the hole. At that instant I fired, and it dropped dead ; on examination I was interested to find that it was a female. Once more the nuthatches gave a striking example of their intrepidity, for the report of the shot had hardly died away when they were both back at the tree resuming operations with as much apparent unconcern as if nothing at all had happened. I mounted guard a little longer and presently shot another starling on the tree, and by way of enforcing the lesson hung its body up within a few feet of the hole. Know- ing, however, the pertinacity of these birds, I did not feel too sanguine even then that the mischief would go no further. On the following day, when I went into the garden before breakfast, the first thing that met my eye was a nuthatch on the path in front of me where it was busily picking up mud. This it did by carefully detaching and rolling together a pellet about the size of a shilling, with which it flew off straight to the hole. A single glance at the latter more than confirmed my misgivings. The starlings had not only removed every trace of the pro- tecting clay but had actually ejected the egg from the nest; the broken shell lay on the ground beneath. Undeterred by the grim scarecrow before them a num- ber of these mai-auders had gathered on the scene and were apparently actively disputing the possession of so desirable a building site. Desperate but determined as ever, the nuthatches used most strenuous efforts to get the gaping hole plastered up afresh. But against such odds their present task was about as profitable as pour- ing water into a sieve, and it was only too obvious what the end must be. At this critical moment I hit on a plan by which I was able to befriend them to some purpose and make amends for the injury they had previously suffered at my hands. It was simple but effective. With the aid of a hammer and nails, I fastened a bit of wood securely over the hole in such a way as to leave it just large enough for the nuthatches ; this was a rather unsightly makeshift, but a further application of clay served both to conceal the deficiencies in this respect and to restore the original character of the threshold. While this work was going forward, both nuthatches stood on the tree close beside me, and no longer uttered the notes of alarm which had been so incessant before. They lost no time in testing the result when I descended the ladder, and it was a comical sight to see the female's frantic contortions in squeezing through the hole which was now inconveniently small. This, however, was clearly a fault on the right side, and the nuthatches were after all left in possession of the field. The starlings were sensible enough to ac- knowledge defeat, but before doing so one individual (possibly the survivor of the original pair) planted him- self at the mouth of the hole, ,and. thrusting in his head as far as possible, railed at the dauntless little inmate in unmistakable Billingsgate. Then he like the others decided to raise the siege, and peace reigned once more. A whole fortnight passed, and the nuthatches toiled indefatigably to make good their own defences behind the improvised shelter which they evidently considered insufficient ; certainly their previous experience might well justify misgivings as to my present bona fides in affoi-ding them protection. Eventually the traces of their labours could be seen extending inwards to a depth of more than six inches. During this period I observed that they generally repaired to one particular sjjot on the path in order to fetch their supply of mud, coming and going with such singular directness that, when one day I had inadvertently placed myself where I interrupted the traflUc, I was startled to see the busy little worker pass and repass within a foot of my head with an absolute disregard of my presence. A well- known writer has indeed suggested from close observa- tion of a tame nuthatch that these birds are peculiarly short sighted, and while the action I have mentioned does not necessarily support such a theory (which in- deed it is hard to accept without further evidence) it has a certain interest as bearing on the question. It is satisfactory to be able to record that this pair of plucky birds eventually brought off their brood tri- umjihautly after all their pei-secutiou, and appear likely to enjoy for a long time to come the security that they have done so much to earn. STANDARD SILVER: ITS HISTORY, PROPERTIES AND USES. -I. By Ernest A. Smith, assoc.r.s.m., f.c.s. At a very early period of the world's history silver was used as a medium of exchange, and also for domestic and public purposes. Gold and silver appear to have been iu general use as money from the time of Abraham, while vessels and ornaments of the precious metals were common in Egypt in the times of Usertsen I. (about b.c. 2433) and of Thothmes III. (about B.C. 1600), the contemporaries of Joseph and Moses.* In ancient times the metals were used in their native or unalloyed condition, but alloys of definite com- position or standard alloys were adopted for the purpose of coinage and also in the arts as early as B.C. 500, and probably earlier. " The reasons for the use of alloys, in preference to pure metals, ai'e somewhat complex. In early states of civilisation coins axe generally made of more or less pure metal, but a nation does not advance far in its histoiT before the very important fact is recognised that alloys are more durable than pure metals, and that their substitution for pure gold or silver affords a notable source of revenue. " In cases where the coinage is in any degree inter- national, the adoption of a low standard by one nation has to be followed by neighbouring nations, in order to prevent loss, and to facilitate commerce by avoiding the necessity for tedious calculations as to the rate at which coins may circulate in the respective countries."! With regard to the actual standards of fineness or amounts of precious metal present in any given alloy which have from time to time been employed, it may * 'WilkiDsou's "Ancient Egypt," III., 22.'5. t Bobci'ts-Austen, Cautoi- Loctuivs on " AUovs IVir Coinage," Society of Arts, 1884, p. 14. May, 1901.] KNOWLEDGE. 103 be reniai-ked that in the numismatic histoi-y of the world endless corabiuations of precious and base metals have been represented. Gold and silver on account of their comparative soft- ness and flexibility are never employed in a pure state, but are almost universally alloyed with a certain pro- portion of copper, the alloys being made up to definite proportions or " standards." Although it is generally known that silver coins and plate are not made of pure silver, few people have very definite ideas as to the composition of the alloys which are employed for these purposes, and still fewer are aware that the amount of base metal added to the silver is guarded with the most rigorous care. In the British Isles the projjortiou of silver in coin and plate is regulated by law. It is enacted that British silver coin and plate shall consist of 11 ozs. 2 dwts. of fine or pure silver and IS dwts. of copper in the troy pound, or 925 parts of fine silver per 1.000 parts of alloy. This is termed sterling silver, and was fii-st particularly defined by statute in 1576 {18th of Elizabeth, c. 15). Many derivations haVe been offered with regard to the word sterling, but the most probable and the one now generally adopted is that given in a well-known old book entitled '' A new Touchstone for Gold and Silver wares,' published in 1679. In this very interesting work the author states (on page 8) that the expression sterling-alloy is derived " from the Easter- lings, or men that came from the East part of Germany in the time of King Richard the First, and who were the first contrivers and makers of that alloy," The purity of their money was famous, and it is supposed that coiners were fetched from Eastern Germany to improve the British currency. Stow, writing in 1603, | gives a similar explanation. He says " the money of England was called of the workers thereof, and so the Easterling jjence took their names of the Easterlings, which did first make this money in England in the reign of Henry II., and thus I set it down according to my reading in Antiquitie of money matters, omitting the imaginations of late writers, of whom some have said Easterling money to take that name of a starre stamped on the border or ring of the penie ; other some, of a bird called a stare or starling stamped on the circumference, and others (more un- likely) of being coined at Stiruelin or Starling, a town in Scotland." With regai'd to the adoption of an alloy containing II ozs. 2 dwts. of silver in the pound troy as a standard for the silver currency of this country. Sir Roberts- Austen§ has pointed out that the adjustment of the relative proportions of the pi-ecious and base metals is undoubtedly guided by the particular system of weights used. The fineness of alloys of silver has from very early times been computed by divisions of the troy pound, which weight is still retained in weighing gold and silver. The Commissioners appointed in 1868 to enquire into the condition of the Exchequer Standards]] state that " the troy pound is said to have been derived from the t ■' A SuTTey of London," by Jolin Stow, p. 52, KiOS. (Jiioti'd l.y Roberts- Austen , p. 14, Ibid. S Ibid., Cantor Lecture, p. 1.5. I Third Report of Comraissioneis. Pai-liaincntary P;ipcr. c. '■'■(>, )). iii., 1870. Roman weight of 5759.2 grains, the 125th pai-t of tho large Alexandrian talent, this weight, like the troy pound, having been divided by the Romans into twelve ounces," luid they add, " the troy weight is universally allowed to have been in general use from the time of King Edward I. The most ancient system of weights in this kingdom was that of the moneyers' pound, or the money pound of the Anglo-Saxons, which continued in use for some centuries ;ifter the Conquest, being then known as the Tower pound, or sometimes the gold- smiths' pound. It contained twelve ounces of 450 grains each, or 5,400 grains, and this weight of silver was a pound sterling. The Tower pound was abolished in 1527 by a statute of King Henry VIII., which first established troy weight as the only legal weight for gold and silver. From that time to the present our system of coinage has been based on the troy weight." In connection with the standard 925, it may be re- marked that a Roman silver coin of the Triumvir Antoninusll (n.c. 31) had almost the same composition as British silver coin, as it contained — silver 925, copper 71, lead 2, and gold 1. The standard 925 was probably first introduced into England by the Saxons, as the Saxon pennies were of the same standard. A number of coins issued before the Norman Conquest have been assayed by Roberts- Austen,** from which the following results have been selected. A coin of Burgred, King of Mcrcia. (852-874 A.D.), contained only 332 parts of silver in the thousand, while one of Ethelred (978-1016 a.d.) con- tained 918 parts of silver, and was probably intended to represent the standard 925. A coin of Canute (1016-1035 A.D.) proved to be of the standard 931, and was also intended, in all probability, to represent the English standard. Anglo-Saxon and Anglo-Norman coins are believed to have been of the standard 925 ; a coin of William the Conqueror when assayed proved to be of the standard 922.8. In England the standard 925 appears to have remained unchanged until the thirty-foui'th year of King Heni-y VIII. (ah. 1542), when, as will be seen from the following table, a great fall in the fineness took place. Table showing the AJlerations in Fineness of Knglish Standard Silver, from tlie reign of William the Cnni|iieror to tliat nf Edw;inl \' 1 1 . ; Fineness of Silver. Dute. lleiifU. In the Pounil Parts Ti oy. per 1000. OZS. .Iwl. Klfiti William f. 11 2 925 to to ir,i2 ■M Henry Vin. HI (I 8;!:i-;i 1545 ;w Ilenrv A' I IT. (i II .5 92^7 *i "Die MetalUirgie. Melnllvcrarbcil iing." A. Ledebur, |i. H(i, 1882. ** //till., Cantor l.eeture.'i, pnjii- 17. 104 KNOWLEDGE. [May, 1901. The table shows that in 1545 the standard alloy con- tained only one-half of its weight of pure silver, and in 1550 it was still further debased, and contained only one-fourth part of pure silver. The restoration of the silver staiidaid, begun in the reign of King Edward VI., was completed by Queen Elizabeth, and it has not been since debased. (To be continued.) THE TYPES OF SUN-SPOT DISTURBANCES. By the Rev. A. L. Cortie, s.j.. f.r.a.s. During the last twenty years some 3800 drawings of the solar surface, on a scale of lOi inches to the sun's diameter, have been made at the St"ouyhurst College Ob- servatory, during the period 1880 to 1890 by means of the 8-inch equatorial, and since the latter year by means of the Perry Memorial 15-inch ecjuatorial. The prin- cipal spots in this long series of drawings have recently been tabulated in a form wliich gives their complete life- histories from their first appearance to their final ex- tinction. Accompanying the tabulations, are a series of charts which show at a glance the chief phases in the development of a group of spots. The object of these tables and charts was to compare individual spots on the sun and magnetic storms on the earth, and the results of the comparison were presented by Father Sidgreaves to the Royal Astronomical Society last December. But besides this primary object for which the tables and charts were drawn up, they have served, and, it is hoped, will serve for many other subsidiary studies with regard to sun-spots. One such study led to a paper read at the last meeting of the British Association at Bradford, of which some account is presented in the following pages. It is comparatively easy from the charts, not only to study the changes in individual spots which take place during their appearance on the sun, but likewise to compare outburst with outburst. From this comparison it was soon seen that there exists a great family likeness between all outbursts of sun-spots, whether we deal with the great storms when the solar activities reach their maximum, or the feeble manifestations of the solar forces at the epochs of minimum. Should an observer look at the sun at a time of maximum activity, he will probably see its surface covered with many spots seemingly in all sorts of forms and shapes ; as scattered dots, or as trains of spots, or m a form in which two larger spots pre- dominate in a group, or again as a single deep black spot, of round and regular outline. Yet all these varieties are but phases of one well-marked and general type through which, as a general rule, all groups of spots pass during the course of their life-histories. In a normal outburst the sequence of the phases is as follows. Wc must pre- mise, however, that in short-lived spots all tiie various stages or phases of the type may not be reached, but only the earlier ones. A group of spots first appears in the form of a few scattered dots or small spots. These spots grow with great rapidity, and in three or four days at the most after their birth, begin to aggregate, and reach a second characteristic phase in the process of development. This is marked by the predominance of two main spots in the group, one in the forefront, and the other in the very rearmost position of the group. In this phase the preceding of the two spots is for the most part the more compact and regular, its fellow being generally in-egular and ragged in form, and made up of semi-detached patches of umbra and penumbra. Many times, however, it covers a greater total area than the leader of the group. This stage is reached by almost all groups of spots, even very small ones, and any theory as to the origin and development of sun-spots must needs explain why two spots, one in the forefront and one at the roar of the group should always predominate. The preceding of the two main spots, as a rule, then, rushes forward with a large proper motion in longitude, by this means in- creasing its distance from the rearmost spot. At this period in the life-history of the group, the space bet,veen the two spots becomes filled by a train of irregular un- formed spots, and penumbral patches of no veiy great size, the whole train of spots thus formed arranging itself into a stream more or less parallel to the solar equator. This tyjDe is accordingly reckoned as the third in the order of succession in a normal outburst. It occurs ordinarily between five and seven days after the first appearance of the group. At times a retinue of companion spots follows both the chief members of the group, and more rarely is confined to the rearmost spot. This phase is not very stable or of long duration, and the two main spots survive after its disappearance. Hence there is a recurrence from the third type back again to the second. Of the two surviving spots the following one generally breaks up and disappears in a few days, leaving the leader to form into a dense black round spot of regular outline. This accordingly has been reckoned as the fourth type or phase in the stages of the life-history of a group of sjDots. Although it is the leader that generally survives to form the single spot, yet instances are not wanting in which the reverse has been the case, the leader dis- appearing and the rearmost of the two spots remaining (e.g., 1892, July 4 — October 5). A few cases are on record when both the chief spots survived to form regular spots (e.g., 1881, October 14 — December 17). Again, the single surviving spot, accompanied or unaccompanied as the case may be by small companions, may never become a round regular spot, but may maintain an irregular shattered appearance of a collection of umbr MR 31 AP 3 AP, 5 rvd U IVd ^ AP 24 2e 29 rv ^ ■ \ 1 1 » * •- ^^ #• »• '% \ MY 18 19 20 21 22 25 24 25 26 27 28 29 30 IV * . '.•* iV •' I 1 If * * * ♦ ^^ %': ^ \ « Jn. 14 15 16 17 18 19 21 22 23 25 1 y r fc* * «i» v » 1 6': k f ^ • J Y 12 13 1 + 15 17 LIFE HISTORY OF A SUNSPOT GROUP. ILLUSTRATING FOUR TYPES. From tlie Sionvhiirst Uniwiiii^s. 1SH4. May, 1001/ KNOWLEDGE. lo; Slight variations from the normal types, or sub- divisions of the same, have so far been indicated by placing lettei's after the four type numbers. The illustration, which shows not only the four types, but their sequence, is that of a large sun-spot group which first appeared on the sun on March 31, ISS4, and lived for lOS days to July 17, passing the central meridian five times. The five horizontal sections of the plate correspond to the five rotations. The spot group was born at the centre of the visible disc on March 31, when it appeared as a few scattered dots, the first phase or Type I. of our divisions. By April 3 it had reached the phase, designated by Type II., when two main spots predominated. Thus it continued until the oth, when the train appeared between the two spots, corresponding to Type III. On April Gth it was near the sun's western limb which it passed on the 7th. At its return it was first recorded on the 22nd, appearing on that date and on the three following days as an elongated single spot with a train of smaller companions. This phase is represented by one of the subdivisions of Type IV. On April 26th and the following day it had reverted to Type II., and on the 2Sth, 29th, aiid 30th to Type I\., subdivision '/. Thus it remained until it again passed the western limb on May 4th. At its next two returns, when it was followed during each of the thirteen days that it was visible, it had become a single round spot, the normal spot of Type IV. It will be noticed that during the fourth appearance a sm.all subsidiary group formed to the north of the original group, and that even in this small outburst the two spot type is evident. At its fifth appearance, when it was gradually disappearing, it had resumed the phase which belongs to Type I. A closer examination of the series of phases represented on the plate will show many other interesting points, as for instance the formation of tails to the leading spot of the group, and the narrowing of the penumbra on the side of the spot turned towards the sun's centre in ro- tation the third, even before it had reached a position near the limb where the effect of perspective would have been apparent. The illustrations are drawn to a scale of lOi inches to the solar diameter. In a subsequent paper the relation of faculae to sun- spot groups will be dealt with. CONSTELLATION STUDIES. By E. Walter Maunder, f.r.a.s. v.— THE SCORPIOX AND THE SERPENT- HOLDER. How many constellations did the original Chaldean Zodiac contain, — eleven or twelve ? The question is a very important one as bearing on the origin of the Zodiac, since the twelvefold division is significant of the ancients having determined the length of the year at least approximately before the constellations were mapped out. The assertion that the Chaldean Zodiac consisted originally of only eleven constellations is made explicitly by Servius the grammarian, in his commentary on the works of Virgil. The latter in his address to the Emperor Augustus, in the first Georgic, suggests that the space which lies between the Virgin and the following Claws, lies vacant for him ; " the glowing Scorpion drawing back its arms and leaving for him a more than ample space of sky." Our Greek authorities, however, made the signs of the Zodiac twelve in number, but gave to one of the figures a double space; the Scorpion occupying one sign with its body and another with its outstretched Claws. Brown's explanation of this double honour given to the poisonous reptile is very ingenious. Quoting from Aratus. he points out the old legend of how Orion was slain bj' a gigantic scorpion in punish- ment for his attack upon Artemis : — " And great Orion, too, his (the Scorpion) advent fears. Content thee, Artemis 1 A tale of old TelU how the strong Orion seized thv robe When he in Cliios, with his sturdy mnee A hnntor, smote the beast to gain (Knopion's thanks. But slie fortliwitli another monster bade — Tlie .**c-c>rpion, liaving cleft the island's liills In midst on either side : Tliis, huger still, His greatne-1 Ila^ue, Vpga's beams directs the enquiring eye Where Scorpio's heart, Antares, decks the southern summer skv." Ophiuchus is engaged on a double labour. Aratus describes him thus : — " His feet 9t:imp Scorpio down, enormous beast. Crushing the monstiTS eve and plaited breajt. AVith outstretched arms he holds the Serpent's coils; His limbs it folds within its scalv toils; With his right hand, its writhinj tail, be grasps ; Ita swelling neck, his left securely clasps. The reptile reais its crested head on high Reaching the seven-starred Crown in northern sky." The head of the serpent is marked out by five stars in the shape of a capital X, immediately below the semi- . ^ ..iyiS'-^ CASSIOPEiX /<^ . CYCJJllS-,^ ~'» e MINOR CAI^aOPAROUS ^c»' >^+ a^^f^ *■ '#•..•.••.*?> « UKCi HERCULES . v^^ > cotom* • VIROC • • e» • • LUPUS The Midnight Sky for London. 1901, Hay 6 circle of the Northern Crown. The five stars are Beta and Gamma at the feet of the X, Kappa in the centre, and Iota and Rho at the top. The small stars cluster- ing near this X of the Serpent s head make an interest- ing field to the opera-glass, Isut the tip of the tail, marked by the star Theta, is more interesting still. Theta may be found by drawing a line from Beta Herculis through Alpha Ophiuchi, and it is situated in a striking channel in the Milky Way, one side branch of which comes to an end Just on the borders of Ophiuchus. THE NEW STAR IN PERSEUS. The following is an abridgement of Harvard College Observatory Circular Xo. 56: — The cable message an- nouncing the discovery of a new star in the constellation Perseus, by the Rev. T. D. Anderson, was received at the Observatory early in the evening of February 22, 1901. Owing to clouds, the new star was only occasionally visible, and twice it was necessary to cover the instruments on account of falling snow. During the int creature wc now term the laucelet as "a kind of slug, under the name of Limax Idnccvlalus, he little realised the interest and importance attaching to his discovery. T,ittle by little the true alliuities of this lowly chordate have been worked out ; aud we now know that, instead of being represented only by a single species, the lancelets include quite a number of different types, which may be arranged under two generic and several subgeueric groups. According to Mr. A. Willey (Quart. .Jouru. Micr. 6'c/i.'»cc, March, IS'Ol), tliese may be classified as follows: — • Genus I. — Bkanchiostoma ; generative structures bi serial. Subgenus 1. — Branch iiistoma. „ 2. — Dolichorhynchus. (Jeiius II.— Epigonichthys; generative structures uniserial. Subgenus 1. — T.), Assisfani hi the Mnseiim of Si'ience and Art, Dublin. BEETLES. Beetles are so very numerous, dominant, and widespread in all parts of the world and in all sorts of localities that the presence of a fair nvimber by the tidal margin might reasonably be expected. And although if indi- vidvials be counted up, marine beetles will probably be found fewer than marine spring-tails, it is likely that in the number of kinds that occur, beetles outnumber all other insects, except possibly the flies, by the searshore, as they seem to do in the world at large. The general fonn of a beetle is known even to those who have never studied in detail the structure of insects! The most characteristic feature is the modification of the forewings into firm plates of leathery or horny tex- ture, to serve as shields — " wing-cases '' or elytra — for the membranous hindwings — alone used in flight — which can be folded beneath them. Beetles thus form an easily recognised order of insects — the " Sheath-wings " or Coleoptera. And the folding up and putting away of the wings beneath their horny sheaths, as jjractised liabitnally by beetles generally, is suggestive of the fact that many beetles have entii-ely lost the power of flight. As a group the beetles have largely forsaken an aerial for a terrestrial life. Their armour-like coats, and the frequently flattened form in very many of the families, correspond with a life on the ground beneath stones, and in such concealed lurking places. Con- sequently adaptation to tidal conditions is less difficult to beetles than to typically aerial insects, and hence the largei number of marine represen- tatives of the order. Among the spring-tails we found that several large genera have each several species adapted for life on the sea-shore. The same state of things occurs among the beetles, but here the adaptation has proceeded further, since we shall find not species only but genera entirely confined to the tidal margin. A high degree of specialization for marine life has, there- fore, been reached by many beetles. It is well known that beetles undergo a " complete " transformation, the young insect being hatched from the egg as a grub or larva — wingless, and more or less tinlike its parent, and attaining the perfect state only after passing through a period of rest as a pupa, in which the form of the organs of the future beetle can be clearly made out. There are many interesting steps in the progress towards a truly marine life that can be studied among the beetles. In the great family of the Leaf-beetles Chrysomelidse), there is a genus (Donacia) whose species, fovxnd on freshwater plants, spend most of their time entirely submerged. Their grubs live at the bottom of the water, feeding on the roots of aquatic plants, and they are provided with two spines on the eighth abdominal segment, by means of which they pierce the roots and breathe from the air-spaces enclosed therein.* An allied genus, Haemonia, has a species //. C'urtisii, Lac, found in brackish water on that charac- teristic marine plant the grass-wrack (Zostera). A similar jDrogress towards life in the sea can be traced in other groujDS of water-beetles. The Gyrinidse or " Whirligig " beetles, whose quick mazy dance on the surface of ponds and streams is well known, have a species {Gyrinus viarinus, Gyll.) which is ttsually found in brackish water, though it also occurs in inland, fresh- water localities. Among the aquatic beetles of the family Hydrophilidse — characterised by the unusual length of the palps or jaw-feet of their first maxilla?, and their remarkably short feelers, the genus Ochthebius has several species, which frequent brackish ponds 'and ditches near the coast, and others which haunt stagnant rock-pools that are, at least dtiring the high spring-tides, washed out by the rising sea. Many of these Ilydrophilidce are not truly aquatic in their habits, but live in marshy places and damp decay- ing matter. To this section belongs the genus Cercyon, which has two species (C. littoralis, Gyll., and C. depressus, Steph.) inhabiting the sea-coast, and often * L. C. Miall. " Tlio \:ituriil Historv of Ai|iiafip Insects.'' Lonilnii )89.') (pp. 93-96). May, 1901.] KNOWLEDGE. 115 occiirriug below high-water mark. These have iuvaded tlie tidal aiea not from the frcshwators, but from the h»nd. Most, sea-shore beetles, indeed, are iuciusoi-s from the laud. Many beetles of various families abound in salt-marshes and on coast sand-dunes ; certain kinds can be traced down to high-water mark, whilst the most characteristic beetles of the sea dwell between tide-marks and undergo immersion twice every day. In temperate countries at least, the Rove-beetles (Staphylinidae) form the most numerous family of the order, and on the soa^shore they maiut^ain this pre- dominance. The form of these beetles is generally known. They are usually narrow, elongate insects, with very short wing-cases, beneath which the membranous hind-wings are nevertheless completely folded up and hidden when at rest. The hind-body, not as in most beetles, covered by the wing-cases, but projecting far beyond them, has all its seven segments firm-skinned and freely movable, so that this part of the insect can be turned about at pleasure ; a number of Rove-beetles carry it turned upwards, as a scorpion carries its tail. Most of the Rove-beetles prey upon insects smaller or weaker than themselves. Many salt-marsh and sand-haunting Rove-beetles belong to the large genus Bledius, which, with some allies, differs from most genera of the family by the feet having only three (instead of five) segments. The Bledii dig bui-rows in the sand or mud, and the material they throw up forms little heaps or castings. Several species live on sandy sea-coasts. The habits of B. fuscipes, Rye, were observed with some care years ago by Mr. K. Taylor ; these insects seem to live amicably in pairs. At the bottom of a vertical bui-row about an inch and a half deeji, one individual — presumably the female — was found, while her mate mounted guard in a short horizontal tunnel opening out from the burrow near the surface of the sand. Xearly allied to the Bledii, and of somewhat similar habits, are the smaller, more hairy and less spiny beetles of the genus Trogophloeus. These arc often found in marshy places by the banks of streams. A new marine species, T. anglicanus, which has lately been described by Dr. Sharp from specimens discovered near Plymouth, is of uncommon interest, since it seems to be almost idantical with a beetle (T. unicolor, Fauvel) of similar habits that lives on the coast of New Zealand. M. Fauvel, indeed, does not consider that the slight struc- tural differences wairant specific seiparation. In his record of the discovery. Dr. Sharpt discusses the problem of this strange similarity, and considers that the only alternative to the highly unlikely suggestion that the insect has been brought by ships fi'om the other side of the world, is that closely similar species have been inde- pendently developed here and at the Antipodes, under similar conditions of life. The possibility of a multiple origin for the same kind of animal in different localities can hardly be denied, since it is certain that the same variety can be thus independently produced under similar conditions, and what is a variety but a species in process of being made? Quite a number of Rove-beetles may be found running among the decaying seaweed that is cast up by the high tides. Several of the large and widely-spread genera of these insects have each two or three species living in this way. The genus Aleochara for example (charac- terised by the presence of an extra tiny segment on each + D. Sliarp. " Some undescribed Species of Trogophloeus." Ent, Mo. Mag. XXXVI., 1900, pp. 230-4. palp or jaw-foot) has three seaweed-haunting species widely distributed around our coasts. These are> charac- terised by their dull blackish bodies, having a thick whitish hairy clothini;. Such a covering is very often "... ® ." found on marine insects ; its use to them is evident, as it serves to retain a layer of air around them when they undergo immersion. Even when covered by water they are not really wetted. Similarly the largo allied genus of Homalota has a small group of marine species. In their general aspect, the pale hairy clothing, the relatively short feelers, and the parallel sides of the hind-body, these Homalota; arc remarkably like the Aleocharse just mentioned. By some authorities, therefore, the two groups of beetles are believed to be closely allied. But the minute stinictural differences between them — the number of segments of the palps and of the fore-feet for example — seem to show that their likeness to each other is the result of a con- vergence under similar conditions of life. J Belonging to the same group of the Rove-beetles as the Homalots are some small insects belonging to the genus Myniiecopora (or Xcnusa), altogether adapted to a sea- shore life, only being found close to the water's edge, ciud often occurring between tide-marks. Two kinds — M . uvida, Er., and M. sulcata, Kies., inhabit our shores. These little insects may be seen either running briskly among the seaweed and on the rocks and shingle, or flying quickly in the sunshine. Sometimes they may be observed to alight on the water of a rock-pool, then, their expanded wings serving as sails, they are easily blown along on the surface-lilni. Both the Aleocharje and the Homalotae are small insects — only about 3 mm. (J- inch) in length. There are, however, some more imposing Rove-beetles found among seaweed, measuring from 5 to 12 mm. (4 to ^ inch). These are the species of Cafius, all of which seem to inhabit the sea-shore, or at least the mai-gins of tidal livers; they are nearly related to the beetles of the large and dominant genus Philontlius. We have four species on the British coasts — C cicatricoms, Er., C. Fig. 1. Fig. 2. Fig. .3. FlO. 1. — Actocharis Readingii, uiagniBed 15 times. Fig. 2. — Grub of Cafius, magnified 4 times. Fig. .3. — Cafius fucicola, magnified 4 times. fucicola, Curtis (Fig. 3), C. xantholoma, Grav., and C. sericeu.?, Holme. The first of these seems confined to the south coast; all the others are widespread, but only C. xanfholoma can be considered common. C. sericeus IS the only species of Cafius which has the woolly covering usually characteristic of marine insects. As one turns JW. W. Fowler. "The Colcoptcra of the British Islands." London, 1887-91. L. Granglbauer. " Die Kafer von Mittelcuropas," Wicn, 1892, etc. 116 KNOWLEDGE. [May, 1901. over the damp seawrack, one sees these beetles darting rapidly about ; sometimes they biu'row into holes in the sand. Deeper search among the heaps of seaweed may reveal their grubs (Fig. 2), which are narrow and pointed towards the tail end. the head as in the perfect insect is large and powerful, the legs strong and spin}-, and the body rather strongly armoured. Both beetles and grubs appear to prey on the maggots which feed on the decay- ing vegetable matter found so abundantly in these sea- weed heaps. A little assemblage of Eove-beetles, to be looked for almost exclusively below high-water mark, are especially interesting. Actocharis is a genus of only one species — A. Readingii, Sharp — found on our coasts only in Corn- wall and Devon, but occurring also on the French and Sicilian shores. This rare beetle is veiy small, only 1.5 mm. (about ,V inch) long and of remarkably narrow form, even for this family (Fig. 1). This fragile little insect, covered with a dense silky pubescence, and with its unarmed legs very broad and flat, oilers a strong contrast to the powerful and spiny Catius. Some of its characters — such as the incomplete fusion of the jaair of jaws (second maxilla") forming the " lower lip — mark it as a very ancient type. The species of "Phytosus are not quite so small as Actocharis. Their shape is characteristic, the hind- body widening towards the tail-end, and the feelers being relatively very short. Three kinds — P. spinifer, Ciu'tis, P. balticus, Kraatz (Fig. 5), and P. nU/riieiitris, Chev., inhabit our coasts ; these little beetles tly in the sun- shine. The first^named is often found running on rocks or shingle, while the two latter usually jirefer to lurk inider seaweed or refuse ; a dead starfish often serves both as shelter and food for a large colony. These beetles occur all along the coasts of western Europe and north-western Africa; other kinds inhabit the shores of North America, and the genus reappears far away in the southern seas on the Falkland Islands and Kerguelen. Long considered as exclusively maritime, Phytosus (P. balticus (has lately been discovered almost in the centre of Ireland — that country of ancient survivals — on an islet in the freshwater reaches of the middle Shannon. Fig. 4. Fig, 5. FiQ. 4. — Grub of Phi/tosus niffriventris. (Aft«r Fauvel.) JIaguified 24 times. FiG. 5. — Phyiosux balticus. Magnified 24 times. The grub of Phytosus nigriventris has been described by Fauvel.§ It is remarkable in being very like its § A. Fauvel. " Xotice sur quelques Aleocliaricns et description de Larves de Phytosus et Leptusa." Ann. Soc. Enf. France (4), II., 1862, pp. 82-94, pi. II, parent-beetle in shape, narrowed at the base of the hind- body and broadened towards the tail-end (Fig. 4), Such a likeness between perfect insect and grub is clearly a sign of antiquity, for the most highly-organised insects are the most unlike the larv» whence they develop. The active, highly organized blowfly, for example, stands in the most extreme contrast to its sluggish degraded maggot. (To he continued.) MiTlStt ■>.■ ORNiTHOLOGlCA a "\y h ■i5Ci-' NOTES:-. Conducted by Harry F. Witheebt, f.z.s., m.b.o.u. Notes on the Singing of a Song Thrush. — On the 24th of March, at 5.30 a.m., a thrush commenced its morning song in a garden at Stroud, where I was stay- ing, and continxied, with pauses of the usual brevity till 7 o'clock, when it was silent for rather more than two minutes by my watch; after which it sang till 8.15. It was not in the garden later in the day till 4 o'clock, when it began its evening song. This I did not time ; but I feel sure that it exceeded two hours altogether. The musical range of pitch did not often exceed 3 J tones, saj-. from C up to G. But sometimes an additional higher or lower note was given, so that) thei full range might have been an octave. Probably the bird sang elsewhere during the day, for in 1885 I timed a thrush (a very exceptional singer) for 16 hours in one day. The chief point of interest in such performances is not mere duration of song, but the great variety of the component sounds. In the present instance I counted thirty difierent strains or kinds of songs in the space of a quarter of an hour; and the first two dozen of these were given almost in succession. The last few, however, were heard at intervals in the reitera- tion of the commoner strains. From long familiarity with the subject, I made the record with some con- fidence. One cannot affirm that aU these songs or strains were deliberately modulated ; yet, .when one remembers how much easier it would be for a thrush to repeat one strain time after time, as do the inferior songsters, it is apparent that this pleasing diversity must be intended. And difi^erent thrushes attempt it with unequal success. There is no positive proof that the thrush studies and deliberates in his singing, but the circumstantial evidence to that effect is strong, suggests ing that the bird has a much higher plane of pui-pose and method than the mere prolongation of singing implies. It is remarkable that until the last few years the mimicry of the wild song thrush was never observed, or at least, never recorded. Yet some thrashes mimic almost as distinctly as starlings ; and there are few pleasanter pastimes in warm weather than to rest under a tree in which a thrush is singing, and to May. 1901.] KNOWLEDGE. 117 notice his varying success in efforts to reproduce some woll-kuown cries of other coninion birds. — Chaulf.s A. AViTCHEl-L, Clieltenhain. Xulcracier (h Sussfj- (Zooloqixl, Maivli, 1901, p. 107). —Mr. II. Mariuiiduko L!»n2;iliile ivcord-i that a Nutfra.'ker was sliot on Di'Oi'm- lior 21st. IS'OO. at Chilgivvf, iioar Chiohcstor. This bird was prubahlv H straggler fiMm the iuvasion of tlic eastern form of the Xiitcraeker into Scandinavia, Oennanv and Holland (see Kxowlbhok, Novem- ber, 1900, p. 2o6L Ilairt/'plumafled Moorhens (Zooloffisf. Jlareh, 1001). — Mr. U. K. Forrest has, during the last three years, examined live speeimens of a singular variety of the Moorhen taken at various plaees near Shrewrsburv. These birds were light yellowish-brown on the upper parts, and very light grey undiTueath. 'J'he feathers, '' instead of having the ]unna" uniti-J into a eompaet web, have them all separate, especially on the exposed portion of each feather." The defect exteuds to the flight feathers, so that the birds could not fly, yet they seemed healthy. By a microscopic examination, Mr. Forrest found that '■ the barbs and liooklets which, in ordinary feathers, cause tlie pinnte to cling together in a compact web, are almost entirely absent on the body-feathers ; whilst in the quill feathers many of the pinme have barbs on one side, but no hookleta to hold them togetlier." Black-tailed Godirit in Co. Wexford (Irish Naturalist, April, 1891,p.9;t).— ilr. (>. E. IT. Barrett-Hamilton records tlial Black-tailed Godwits were very ])lentiful at Kilmore, in Co. Wexfm-d, during December and January last. This bird is an irregular visitor to Ireland at any time, while in winter it has but rarely been observed. Jloneii Buzzard in Soltcai/ (Annals of Scott. Nat. lli.it., .Vjiril, 1901, p. 801. — In an article entitled " Zoological Notes from Sohvay." Mr. Robert Service describes how his friend, Mr. Jardine, found a Honey Buzzard on January 17th last. His collie dog ''set" l>v a sheep trough, and a large " Hawk ' got up and Hew some forty yards. Mr. Jardine followed, and witli no dilliculty caught the bird. It was liberated in a baru,and tlicre ^Ir. Service saw if., and jjrouounced it t.o be a " particidarly fine Honey Buzzard in the most splendid condition.' The bird had no signs of escape from captivity and no wounds, yet it was strangely tame, and allowed itself to be stroked. The appearance of a dog, however, caused its whole aspect to change '' to a fierce and lighting attitude." The Honey Buzzard is a great rarity in Solway. Barred Warbler in Barra (Annals of Scott. Nat. Hist., April, 1901, p. 114).— On October 29th, 1900, Mr. W. L. MacGillivray shot a young Barred Warbler in Barra. This is but the third Scottisli example, and curiously enough all have been obtained in the western isles. Scops Owl in Shetland (Annals of Srof/ish Naf. Hist., -Vpi'il. 1901. p. 116).— In Knoh-i.edoe for August, 1900. p. 181, a bird of this speries was noted to have been captured for the first tiiui' in Shetland. Mr. Clarke now records that a second specimen was obtained in the western part of the main island about the same time as the first. AH contributiotis to the column, either in the way of notes or photograplis, should be forwarded to Habry F. Witherby, at 1, Eliot Place, Blacklieath, Kent. / Conducted by >r. I.Cro§s Illumination with Artiikul Licht. — The lara|i that has proved most universally satisfactory is the regular one sold for microscopical work, with a i-inch or ^-inch wick, but to many people this is objectionable for several reasons, the chief of which is that with the general use of gas and electric light, a mineral oil is not ke|)t in the house, excepting for this special lamp : it also is not clean to handle, and requires a certain amount of attention ; al.so it is not always immediately ready for service when required. In laboratories such a lamp is out of the question, and bare gas jets, or g.is jets with upright chimneys, are generally to bo fouiul. 1 have recently been making some oxperiinents with gas and electric lamps to see if some practical form of illnniinaiit, always available for use without special preparation, cannot bo devised for critical microscopical work. Two important considerations have to 1)0 kept in view, one is that the liglit must bo brilliant, and the other is that it should be possible to focus an image of the source of light l)y means of the substage condenser, in the field of view. .\ very serviceable illumination can bo secured with the AVelsbach' incandescent gas light, but the reticulations of the mantle are an obvious objection, and the Hamo has too large a surface. These can be overcome by means of a shade of metal surrounding tlio chimney at a distance of three or four inches. In this shade a small rectangular or circular .slot should be per- forated. When working, this slot .would be treated as the source of light and focussed accordingly. At a recent meeting of the Koyal Microscopical Society, Mr. Housselet exhibited an incandescent electric lamp of the Kdison and Swan " Focus" type, which has a somewhat coarse lilament not unlike a corkscrew suspended horizontally in the bulb. This lamp gives an intensely brilliant light, and it has on many occasions been used for magic lantern purposes. It was recom- mended that the light for microsco]iical work should bo taken from the edge of the filament and focussed in the .same manner as the wick of an oil lamp. The light arranged in this way was, however, to my mind too much dill'nsod, notwithstanding that a shade was used. On making further inquiry I tind that a stand for an electric lamp is made for laryngological and aural examinations wliich has joints and movements for .adjusting in any desired position. In the usual tyjie it carries an ordinary eight or sixteen candle-power lamp, but it will quite well carry the " Focus " pattern. If now an enclosing shade be provided similar to that described for the Welsbach bght above, with an aperture which can be treated as the source of illumination, an ideal electric light for microscopy is secured. This would answer well also for photo-micrography. A lamp, somewhat similar to the foregoing, has been used by me with considerable satisfaction, though long usage has created a distinct prejudice in favour of the i.-inch wick oil lamp. All workers have not electric current available so this will not appeal to them, lint the majority have gas, ami where oil lamps are objected to, I would advise a trial of the Wclshach light arranged as described above. PnoTo-MI(■R(>l^R.\^IIY with ARf Lamp. — Trouble is in- variably experienced in maintaining the light in one central position, and several devices have been resorted to in order to control this. Xo automatic lamp is really useful for the purpo.se, a hand-fed lamp must be em])loyed. When this is properly .adjusted and the condensing lens is in position, a luminous disc will Lie i=een upon the leaves of the partially closed Iris diajihragm of the substage condenser. During an exposure it will only be necessary to maintain this disc in a fixed position by turning the milled head of the lamp very gently as re(niired, and the light may be kept perfectly central for any length of time. It is ])resumed that a horizontal camera would be used. St.unim; Fi.acki.la. — The pre|)aration of Bacteria so as to exhibit flagella has always seemed to be unsatisfactory and difficult. Very few workers are really successful and none have produced permanent mounts. An interesting note occurs in the Thompson Yates Laboratories Report, by Dr. MacConkey, which deserves consideration. It has been considered essential when staining such prejiara- tions to use a mordant, presumably to fix the dye in the substance of the flagellum. It is suggested that the rendering visible of the flagella in consequence of the use of the mordant is not because of the etfect which it has hitherto been credited with producing, so much as by causing the llagellum to swell and become thicker. The flagella are of cxipiisite tenuity, so much so, that when stained, the dyes do not seem to render them visible to the same extent as when a so-called mordant is used. The suggestion put forward is conlirmed by the state- ment that the flagella appear to be thicker than they are supposed to be actually, and the organisms them.selves are larger after the use of a mordant than when stained in the ordinary way. There are dyes which have the effect of staining the flagelhi deeply anls. Od. per annum. The Secretary would be glad to give further information concerning this Society, and a ticket for admission to any of the meetings, on application to him at the Society's Rooms, 20, Hanover Square, W. ►.*.< NOTES AND QUERIES. 11'. E., Ci-eiae. — The question naturally arises whether the microscope you require is to be used exclusively for petrological work, or do you wish it to be available for ordinary observations. If the former, the " Dick " microscope, by Messrs. Swift & Sons, is exceedingly efficient and comprehensive ; if the latter, Messrs. R. & .1. Beck, and W. Watson & Son.s, offer .some well- designed models. Of Continental manufacturers, R. Feuss, of Steglitz, is the one man whose petrological instruments have distinct advantages. It would be advisable for you to get catalogues from these different people, and ascertain by that means what featui'es appeared to be of special importance for your work, and if then I could give you any further advice or assistance I would gladly do so. The liec. (j. C. J. — Your trouble arises from using cedar- wood oil for clearing ; you will find the following procedure answer well : Dehydrate in absolute alcohol, clear in chloroform, and transfer to paraffiu. ir. //. C. — No further discussion has taken place on the Abbe diffraction theory, so far as I am aware. Diatoms can be found almost everywhere ; the smallest ditch or pool, provided the water is not stagnant, will yield material. The specimen of which you send a sketch is probably a form of Navicula, but it is impossible to tell without actually examin- ing the specimen. You are eligible for membership of the Quekett Club, and either the secretary, or the optical house from which you obtained your microscope, would put you in the way of being nominated. Mr. Cooper AVebb, F.C.S., has sent me a photo-micrograph of the Cat Louse — Tr/clioilectex siihroittmliis. He states that this was " discovered by Mr. Parkes on some English cats at Eastbourne in February last, and may be of interest to some of the entomological readers of Knowi.eiice, for according to such eminent authorities as Denny, Andrew Murray, and, I think, Burmeister, this parasite had not hitlierto been discovered in the country.'' If any microscopists arc interested in the above, I shall be pleased to put them in communication with my correspondent. J. C. Webb. — I am communicating your offer to the society referred to. ir. P. Uinnilton, — I am very much obliged for the red rain (lust, and will mount some and give the result in next month's number. A'. //. .lA. — " Could you kindly inform me whether there is any book published that treats fully on the microscopical anatomy of insects, as I am anxious to take u]) that particular branch of research V " Can any reader offer a suggestion '? li. M. — " I have for some time made a s|)ecial study of Desmidiaceas, especially Closterium, and should be glad to know of some book which treated of the life-history of Desmidiacea3. In particular I am anxious to discover the cause for swarms of Closterium, which in spring time come up from the mud to the surface of the water, quantities of ten to twenty being connected by a thin mucous filament.'' Communications and enqu/rien mi Microscopical matters are cordially invited, and shoidd be addressed to M. I. CROSS, Knowledge Office, 326, High Eolhorn, W.C. NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. The frequency with which periodical comets escape detection is perhaps not a httle remarkable. Recently the comets of Finlay, Barnard (188-t), E. Swift (1894, lY.), and firorsen have been sought for in vain. It is true that the conditions vary greatly at different returns, and are not often reaDy favourable to the detection of these bodies. And in regard to those comets which have only been observed at a single apparition the positions are seldom accurately known. The visibility of these objects is also subject to considerable fluctuations, due to some inherent physical causes which are not well understood and cannot be sufficiently allowed for. Holmes's comet, wliich was, fortunately, detected at its first periodical return in 1899, was exceedingly faint then, though its conspicuous appearance in the autunm of 1892 justified the inference! that it would be pretty bright. The failure in re-detecting some of these interesting bodies is to be regretted, since it is most desirable to obtain observations at multiple returns in order to determine the orbit elements with accuracy. Certain comets are only visible at alternate returns, others at one out of several returns. The numerous failures to pick up these objects cannot be ascribed to negligence on the part of those having the command of large instruments, for the latter have often been successfully employed in work of this kind. Perhaps the effort has not always been adequate to the occasion, and it is to be hoped that some more systematic method will be adopted in future. If combined action were arranged between the possessors of really powerful telescopes every expected comet might be effectively looked for, whereas under present circumstances some comets receive a good deal of attention, while others have very little, and are enabled to elude recovery. The list of periodical comets is now very large, and increasingly so. But many of this class of bodies still remain undetected, and in proof of this Giacobini's discovery, in December last, of a comet belonging to the Jovian family may be cited. Dennino's Comet (1894 I.). — The return of this object is expected during the ensuing .summer, but under circumstances wliicli render it probable that it will escape detection. Herr P. V. Neugebauer gives the following sweeping ephenieris (Ast. Nach. 3700): — I, II. III. P.P. May 9. P.P. Miiy 25. P.P. Jiuie 10. a S a & a 6 April 7 ... 60 6 + 21-7 539 + 19-4 48-4 + 167 „ 23 ... 75-8 + 24-8 07-6 -t- 2:i7 6u 6 + 20-7 May 9 ... 93 0 + 262 834 -I- 25-0 74 8 + 23-5 „ 25 ... 111-2 + 25-6 1UU6 -I- 25-6 91-0 -t- 25-0 June 10 ... 1290 -1-22 7 118-4 + 24-1 108-3 + 247 „ 26 ... 145-3 + 18-2 135 6 -t- 206 1257 -I- 22 4 At the return of this comet in 1894, 293 observations were made, and it was la.st seen on June 5th in the 30-inch refractor at Nice, when its distance from the earth was about 138 millions of miles. Fireball of January 13, 1901. — At lOh. 35m. a meteor sufficiently bright to illuminate the sky was observed by the Rev. S. J. .Johnson, of Bridport. Its course began mid-way between a and 45 Cancri, and ended after a duration of 7 seconds right across Castor. .\t first white, it finally dispersed in a stream of rod sparks. The meteor was also seen at Beaniinster, Dorset, wliere " its illumination resembled moonlight for about 10 seconds, when it appeared to split into fragments and disappear in a brilliant shower." It was also seen at Highbury, N., by ilr. Jewell, who describes it as of exceptional size and brilliancy. The meteor was ilircfted from a racUant at 149'' — ]2', and fell from 61 to 52 miles May, 1901. KNOWLEDGE. 110 over the English Chuuiiel, disappearing 5 miles S.K. of Portlaml Bill. Path about 54 miles and velocity about 8 miles per second, according to .Mr. Johnson's estimate of the duration. The tireball of 1866. Jan. 1 1, liad a radiant at loS'' — S*", and probably belonged to the s«me stream of A llydriils as that of the recent meteor ; but there seems to have been a wide difference in their velocities, for that of the former object was computed by Prof. Herschel as 46 miles \vr second. FiRKB.vLL OK J.vNV.vRY 28.— At about 9h. 22m. Mr. Robert Service, at Dumfries, noticed the Hash of a fine meteor quite as bright as the half-moon, and perhaps a third less in apparent magnitude. In colour it shone precisely like an unshaded electric light, and took about IJ seconds to pass from about 330° + 80° to 300" + ."11". It went out suddenly with an explosion, showing red and blue sparks. Just three minutes later he heard " with great distinctness in the perfectly still air a sort of double detonation from the direction of low down in the N.X.W. . followed by a short thundery rumble, but something in the sound was altogether unhke distant thunder." The meteor was observed by Mr. T. W. Backhouse at Sunderland, who noted the time as 9h. ISni., and describes the object as being one of the most magnificent he had ever seen. It disappeared fi-om view at 342" + 284°, then passing behind a house. Its (light of about 15" was directed from the point 101" + 54°. The metoor exhibited a variety of colours, the chief being orange towards the last, and then for the last 3" or 4° sea- green, at last a very \-ivid green ; while the bright sparkling tapering train of 4" or 5° was orange. It was also seen by several persons at Kdinburgb. The i-ailiant was at about lOG" + 52'^' in the Lynx, and the meteor descended from 76 to 16 miles above I>anark to Strathaven. Path about 61 miles, and velocity 18 miles per second. This brilliant object was directed from the Lvncid radiant, O.C. Xo. LXXXIV., 103.4° + 50.8°, which seems to be visible during the greater part of the year. THE FACE OF THE SKY FOR MAY, By A. FOWLEE, F.R.A.8. The Sun.— Ou the 1st the sun rises at 4.34, and sets at 7.20 ; on the 31st he rises at 3.52, and sets at 8.2. There will be a total eclipse on the I8th, but it will not be visible in this conutrv even as a partial oue ; the belt of totality extends from Mauritius, through Sumatra, Borneo, Celebes, and New Grviinea. Authorities now consider that the minimum of sunsfjots has probal>lv been reached. The Mooy. — The moon will be full on the 3rd at 6.19 P.M., will enter last quarter on the 11th at 2,38 p.m., will be new on the 18th at 5.38 a.m., and will enter first quarter on the 25th at 5.40 a.m. The following are thf principal occultations during the month : — 1 :-i s a a a 0 ti £.•3 — » 1 0 0 a> t St. 1 < -^ < f 0 0 1 0 0 d. h. May 8 21 Sa^^ttarii 4-9 12..W A.M. fc-J 86 1.51 291 im 19 3 „ 9 ■i ii> 12.-'«A,M. 122 l.W 1.23 222 247 20 3 „ 31 B.A.C. 5109 h-i 11.49 p.m. 44 M 12.36 .3.36 319 13 19 There will be a peuumbral eclipse of the moon, partly visible at Greenwich, on the evening of the 3rd. Tlie first contact with the penumbra is at 4h. 6'3m,, the middle of eclipse at Wh. SOvm., and the last contact with the penumbra at 8h. 551m. At Greenwich the moon rises at "h. 28m. The Planets. — Mercury is in superior conjunction with the sun on the 14th, and will afterwards be an evening star, but too near the sun for easy observation. Venus is in superior conjunction with the sim ou the 1st. and may therefore be considered not observable. Mars remains in Leo, and will be in quadrature on the 20th. On the 1st he sets about 2.40 a.m., and on the 31st about 12.56 a.m. During the month his apparent diameter ranges from 9"-0 to 7"'2, On the 15th the illuminated jjart of the disc will be 0'895. Jupiter is still in Sagittarius, rising on the Isl about 12.22 A.M., and on tlie 31st about 10.27 p.m. His path is a westerly one. a little to the south of ^- Sagittarii. Tlic apparent diameter on the 15th is 40"'4. Saturn is also in Sagittarius, rising ou the 1st about 12.35 A.M., and on the lilst about 10.34 p.m. On the 5th he will be 3^ 18' to the east of .Jupiter. The apparent diameter of the planet on the 25th will be 16 ''G, and the major and minor axes of the outer ring respectively 41" '5 and 17"'l ; the ring is thus widely open, and the nnrthorn surface is presented to us, Cranus is in the most southerly part of Ophiudius, to the west of ^ and 9, making a nearly equilateial triangle with those two stars. He rises on the 1st about 10,30 p.m., and on the 31st about 8.27 p.m. Nepttiue can now only be oliscrved for a short time in the early evening, as he sets about 11.17 p.m. on the 1st, and ablaut 9.22 p.m. on the 31st. He remains in Taurus, nearly midway between 132 Tauri and ;^' Oriouis. The Staks. — About 10 p.m., at the middle of the month, Ursa Major will be nearly overhead : Cygnus in the north- east ; Vega pretty high up in the east ; Arcturus a little east of south ; Scorpio rising in the south-east ; Spica Virginis in the south ; Leo in the south-west ; and Gemini a little north of west. Cljrss (Column. By C. D. LococK, b.a. •* Communications for this column should be addressed to C. D. LococK, Netherfield, Camberley, and be posted by the 10th of each month. Solutions of April Problems. (P. G. L. F.) No. 1. 1. Q (<> lt(i, and mates next move. No. 2. Ki'ij-morc. — 1. B to K8. If 1 ... B moves, 2. B to K3ch, etc. 1. . . Kt toB4, 2. KtxKtPch, etc. 1. . . KtxP, 2. Kt to K2ch, etc. ]. . . P to Kt4, 2. R to B5ch, etc. Correct Solutions of both problems received from J. Baddelev, S. G. Luckcock, C. C. Massey, W. H. S. M., A. H. Mac'hell Cox, Endirby, A. C. Challenger, W. de P. Cronsaz, W. Nash, A. .7. Head, G. A. Forde (Capt.), Alpha, G. W. Middleton, H. Le Jeune, F. J. Lea, F. A. Wilcock, .1. T. Blakemore, G. Groom, H. Boyes, .T. S:)wden, W. Jay, J. M. K., G. W., Vivien H. Macmeikan, C. C. Pennington, A. E. Whitehouse, C. .Johnston, Eugene Henrv, J. E. Broadbent, J. A. Nicholson, E. Hunt, F. Dennis, C. Child, C. F. P. Of No. 1 only from S. Jackson. A. Dod, H. W. Elcum, W. Clugston. The two former give 1. B to Q7 for No. 2 ; this appears to be met by 1. . . Kt to B4. Mr. Elcum claims a solution in two moves by 1. B x Kt. Black, however, can pin the Knight by 1. . . li to Bsq. >S'. W. Billiiujs. — The Cheltenham post-mark on your card is unfortunately 10.45 a.m., April lltli. Vour solutions, though correct, cannot therefore count in the competition. Col. Bell. — Many thanks for the information, of which, as you will see below, I have availed myself. 120 KNOWLEDGE. [May, 1901. W. Cliigston. — Thanks for the problem. It is marked for insei'tioii in the August number, the programme till that month being already complete. The solver you mention is well known ; he competed, if I remember rightly, in a solution tourney in Knowledge some eight or nine years ago. J. Bacldeley. — I can only repeat that I know no other wav of getting any decisive result from a competition limited to problems in two and three moves. C. C. Massey. — Your deduction from tlie words " may possibly " is incorrect. The words show that ])roblems of the uatiire alluded to were originally contemplated, but that, owing to their apparent unpopularity, they would, if given at all, be reserved for emergencies. You will see that, in your other reference, you have confused "problems known to have no solution'' with "problems known to have more than one solution." The former class is certainly illegitimate, the statement "White mates in, etc," being clearly of the nature of a falsehood. PROBLEMS. By Mrs. W. J. Baird. No. 1. Black (u). ^ mm mm m. m ^M m ^Wm. rf W>. S V///////^ a V^'/^ ?^'"^ Wffffii White (s). White mates in two moves. No. 2. Black (7). i « W' i m v,-^- r 'mm 1 y//^v/,. W///'- v//y. w Wy//'^ -^^ V///M White (9). White mates in three moves. CHESS INTELLIGENCE. The Anglo-American Cable Match will have taken ]ilace before this page ap])ears. The British team will be weakened by the absence of Mr. Blackbiirne, who, so far as I know, has assigned no reason for his abstention. For- tunately it has been discovered that Mr. Mason is eligible, and he will probably be invited to take Mr. Blackburne's place. Mr. Burn is again not jdaying, and Mr. E. O. Jones will probably })lay instead of Mr. Trenchard, who has been out of form lately. Herr C. Schlechter has again given evidence of consistent form by his victory in the Vienna Club Tournament with a score of 9 out of 11. Herr Alapin was second with 8, and Herren Albin and Marco divided the third and fourth prizes with scores of 6i each. Gloucestershire have defeated Wiltshire in the semi- final round of the Southern Counties' Competition by 10 games to 6. The final tie will jjresumably be against Surrey as usual. The North v. South Cori-espondence Match is just concluding, any games unfinished on April 15 being sent to Mr. H. E, Atkins for adjudication. The full score will be given next month. An imjiortant match between Lancashire and Yorkshire, played at Leeds on March 2ord. resulted in a win for Lancashire by Itii games to 8i. Mr. Burn was playing for Lancashire ; as is often the case he ])referred not to take the first board. Last year Lancashire won by 29-3 to 12^, but in 1899 Yorkshire obtained an easy victory by 20''to 11. Mr. T. F. Lawrence has agani risen to the occasion in the City of London Championship Tournament, having at present won 15 games, drawn 2, and lost 0. The other leading competitors are — Herbert Jacobs, won 14, drawn 3, lost 2 ■ E. 0. Jones, won 1.3, drawn 1, lost 3 ; W. Ward, won 13, drawn 3, lost 3 ; Dr. Smith, won 14, drawn 2, lost 5. A ('orrespondent points out that the chess-board puzzle, which appeared in the March number, had been printed in these j.^ages some years ago. It ajipeared in the August and October numbers of 1886, where it is described as " the fine old (i4 — (55 fraud." The writer of the article suggests a plan for making the discrepancy less obvious by dividing it between the square and the parallelogram, instead of, as usual, allowing it to fall on one of the two. In other words, instead of taking an amount of paper equal to 64 squares, and attempting to convince the victim of the fraud that it is also equal to 65, he takes an amount equal to 64s squares and turns it at will into either an apparent chess-board or an apparent rectangle of 13 x 5. The rectangle is drawn first, and a thin parallelogram of an area equal to half a square is cut out from it and thrown away. For a full description of the ingenious method by means of which, as the writer claims, the discrej)ancy is rendered so unuoticeable that it cannot be detected, even by measurement, those interested in the matter should refer to Knowledge for October 1, 1886. For Contents of the Two last Narabers of " Knowledge," see Advertisement pages. The yearly bound volumes of Knowledge, cloth gilt, 8s. 6d., post free. Binding Cases, Is. 6d. each ; post free. Is. 9d. Subscribers' numbers bound (including case and Index), 2s. 6d. each volnme. Index of Articles and Elustrations tor 1891, 1892, 1894, 1895, 1896, 1897, 1898 1899, and 1900 can be supplied for 3d. each. All remittances should be made payable to the Pubbsher of " Knowledge." " Knowledge ' Annual Subscription, throughout the world, 7b. 6d., post free. Coninuuiications for the Editors and Books; fur Review shonlj be addressed lOilit.irs, " Knowleimie." ^Jtj, Hiijli Holborn, London, W.C. Jink. 1901.] KNOWLEDGE ]21 ILLUSTRATED MAGAZINE S€i£N€£41T£RATt}R£ AART^ Founded by RICHARD A. PROCTOR. VoL.xxr^-.] LONDON: JUNE, 1901. [No. 188. CONTENTS. Antarctic Exploration. Bv WM. Shackt.f.tok, f.h.a.s. (IllusfrateJj On the Audibility of the Minute Guns fired at Spithead on February 1. liy Chahiks PATir^oN, sc.D., FO.s. (lllustrateilj . . Flowering Plants, as Illustrated by British Wild- Flowers.— III. Flowers. By R. Li.oyu riiAKGER, b a. flUiLitratedJ " Constellation Studies.— VI. The Swan and the Eagle. Bt E. Walter MAfXDKU, t.H.A.s. (Jlliixtraln/J New Stars. By the Rev. .V. I,. C'ohtie, s.i. f.r.a.s. Photographs of the Spectra of Nova Persei and Procyon. (Plate.) Notes Letters : SiELiAB Pabaiiax. By W. W. Stbickland. £. Walter Maindeb SrSSPOTS AND TeBBESTRIAL TEMPERATrKE. McKeszik Knight. Xote by Eds. ... CLorns ON Mars. By E. Lloyd .Tones CiorDS ON IIaks. By R. A. Geegoby ... Notices of Books Standard Silver: Its History, Properties and Uses.— II. By Ernest A. Smith. A.s.soc,B.s.M.. F.c.s. .. The White Nile— From Khartoum to Kawa.- II. The River— Essential alike to Man, Beast and Bird, liy HaEKY F. WllHEKBT, F./..S., M.li.O.f. (lUllstratedJ British Ornithological Notes. Conchifted by Hahht F. WlTBERBY', F.Z.S., M.B.O.T. ... Microscopy. Conducted by M. I. Cross. Notes on Comets and Meteors. By W. F. Denning, F.B.A.S. , . The Face of the Sky for June. By X. Fowler, f.r.a.s. ... Chess Column. By C. D.Locock, b.a Tkan 121 124 125 128 V.VZ Xote by 133 By (i. 133 133 133 13-i i:u 137 l-i<> 141 142 142 143 ANTARCTIC EXPLORATION. By W'ji. Shackletox, f.h.a..s. (Phynciat and AKlronomer to- the National Arituvctic . . E.fpedlfion). Historical. Not long ago a voiing reporter, evidently in search of copy and the Commander of the National Antarctic Expedition, was making vain enqiiiries for Captain Cook at the rooms of the Royal Geographical Society. Were that great navigator alive no doubt he would be the first to withdraw the opinion expressed by him " that no man will ever venture farther than I have done, and that the land to the south will never be explored " Cook reached the Tlst parallel of south latitude in 1774, and nearly half a century elapsed before this was surpassed by Weddi'll. who reached 74' 15' south latitude in 1823. A period of IS years brings us to the memorable expedition under the command of Sir James Ross, who in 1841 passed the highest point in southern latitudes hitherto reached, and eventuallv attained the high latitude of 78° 4' S., and ovoii thou was greatly dis- appoiatcd at not being able to reach the 80th parallel, further progress southwards being rendered impossible by the great ice barrier. Although Ross coasted along the great ice barrier for 450 miles in search of an opening to the southwards none could be found, nor does it appear that it was ever of such form as to permit a landing, being described as "a perpendicular cliff of ice between Lot I to 200 feet above the level of the sea, without any fissures or pro- montories on its even seaward face." Upwards of 50 years have again elapsed before this has been penetrated by the members of the recent expedition sent out in the " Southern Cross " by Sir George Newiies, who found the barrier somewliat changed in position from that re- ported by Ross, and actually made a journey of 20 miles to the southward ov(>r it, reacliiiig 78" 50' S. There is no reason to suppose that Ross was mistaken in his determinations of positions, the accuracy of his obser- vations being beyond praise. Our knowledge of the cycle of terrestrial changes in these regions is so meagre that no one can predict the magnitude of the change taking place half a century later. Field of Operations. The two principal expeditions about to start, for the Antarctic regions are under the auspices of the British and German Governmonts, and by mutual agreement they have decided to confine their attention to particular localities. The British expedition has had that half of the Antarctic area assigned tO it which Sir Clements Markham has designated " the Ross and Victoria Quad- rants." Iving to the south of the Pacific and Australasia, between" the meridians of 90° \V. to 180° and ISno to 900 E The German expedition will Map.— Antarctic Area, showing allotments of the two Expeditious. devote its attention to that half diametrically opposite, that is to the Indian Ocean and Atlantic side. The area comprised under this scheme is some 6 million square miles, larger than the whole of Australia; and so vast is the region that probably the two expedi- tions will be nearly 20()() miles apart. The Buitisii Ship. The ship to convey the party from these shores is the 122 KNOWLEDGE. [June, 1901. ■' Discovery," and is the first ship wliich has been specially built in this country for such Polar work. She has a displacement of 1500 tons, with engines of 450 h.p., and to suit her for a magnetic siu-vey, no metals with magnetic properties were allowed in her construction within a radius of 30 ft. from the magnetic observatory, situated on the upper deck. The ship, of which we give an illustration, is expected in the Thames about the end of May, and will lie in the East India Docks to receive the -'supply of stores and in&trunients. Whilst the expedition is planned for a couple of years "-he will hf |)rovisioiird for liiree, should a pioloiigment be necessary. Autarctic Sliip " Discovery" at Dundee (without masts). WlO(oi)/ rJJlJi by H. W. SkELTON, K.N. Personnel. The staff of the expedition is as follows: — Captain R. r. Scott, K.N., is the commander. Lieutenant A. B. Armitage, r.n.r., second in command, and navigating officer (of the P. & O. Company). Lieutenants C. Royds, R.N.. M. Baine, r.n., and E. H. Shackleton (of the Union Castle Line Company). Mr. R. Skelton, r.n., chief engineer. The scientific staff consists of Mr. T. V. Hodgson, formerly of Plymouth Biological Laboratory, biologist ; Dr. R. Koettlitz, of the Jackson-Hannsworth Expedition, chief medical officer and botanist; Mr. W. Shackleton, from the Solar Physics Observatory, Royal College of Science, physicist and astronomer ; Dr! E. H. Wilson, of St. George's Hospital, medical officer for the landing party and zoologist, and a geologist yet to be appointed. The three latter will, it is intended, be put on shore with some half dozen of the crew to fonn a land party. Mr. George Murray, j-.r.s. (the editor of the Antarctic Manual), will proceed with the ship as far as Melbourne ; and during the voyage out he will give the officers the benefit of his experience in sounding and dredging, as a prepara- tion for similar work in the Antarctic area. Other Expeditions. Three otlior expeditions arc in contemplation, one of which, that from Germany, is of similar magnitude to the British. The other two, one from Sweden, the other from Scotland, are of smaller dimensions. The German ship, the " Gauss," has like features to the " Discovei-y," and is being fitted out at Kiel. Her programme will be carried out under the direction of Professor Erik von Drygalski, who has already done Polar work in his study of the Greenland glaciers. He will be assisted by four other scientific men. The ship will be under the command of Captain Hans Ruser, with Hcrr A. Stcho as engineer (both of the Ham burg- American Line). The Swedish Expedition is led by Dr. Otto Norden- skiold, of Upsala University. One naturally associates his name with Baron Nordenskiold, and the discovery of the N.E. passage in the voyage of the " Vega," and he is indeed the nephew of that distinguished explorer, and has himself been on expeditions to Greenland and Alaska. His ship is the " Antarctic." and it is contemplated thj^t in addition to Dr. Nordenskiold she will have six scien- tific men on board, as well as the captain, officers, and crew. It is intended that the voyage will be made ivV; Terra del Fuego, and that the vicinity of the S. Shetlands will form the arena of operations. The Scottish Expedition is to be under the leadership of Mr. Wm. S. Bruce, who has already visited these regions in the barque " Balaena." The plans of this expedition are, however, not so far advanced as tho.se above, but it is understood that Weddell sea will be I its destination. ' Programme of the Expeditions. Whilst the British and German ships form the prin- cipal expeditions, the others will also support and act ill hannony with them. Simultaneous observations will be made of various phenomena on term days, wliich have been decided upon by the committees. For magnetic work the Cape and Melbourne will form the base stations for the ' Discovery," and the Germans have decided to establish a similar station at Kerguelen Island. The detailed in- structions for the British expedition are yet to be drawn up, but the general orders are in the main those with which Sir James Ross sailed. He was " to notice in the S. Atlantic the point where he crossed the curve or line of least magnetic intensity ; to ascer- tain the depth of the ocean whenever pi'acticable, and the temperature and specific gravity of the water at different distances below the surface ; the strength and direction of currents and tides; periodical movement of the barometer ; comparative brightness of stars ; re- fraction ; and to swing pendulums in special localities whereby to prove the figure of the earth. After refitting at Van Diemen's Land he was to proceed direct to the southward in order to determine the position of the magnetic pole, and even to attain to it if possible, which it is hoped will be one of the remarkable and creditable results of the expedition, one calculated to engross the attention of the scientific men of Europe." The programme is a good one. even to-day. and needs little modification, except in so far as may be necessary to solve peculiar features of the Antarctic which have been brought to our notice by the researches of Sir James Ross and later expeditions. Magnetism. The primary object of the expedition is the completion and bringing up to date of the magnetic work done by Ross in the " Erebus " and " Terror." and by Moore and Clerk in the " Pagoda." Since that time no accurate survey of these regions has been attempted, and with June, 1901. KNOWLEDGE. ] 2:5 the ever-changing variation of the neixlle hy unknown amounts, navigation by tlio eonipass much soutli of the Cape is somewhat precaj-ious. Tho utilitv of doing this was recognised by the Government, for which purpose a grant of £15.000 was voted. Whilst at sea the mag- netic elements will bo determined each day by the standard compass, and an improved fonn of the Lloyd dip circle specially designed by Captain Creak, r.n.. for observations at sea. The Fox circle will also be employed. Absolute nieasm-enients of the magnetic elements will be made whenever possible either on the ice or on land, and the relative in.strumcnts compared with them. For the land party recording magneto graphs of the Eschenhagen type will be set up. a similar set of instruments being taken by the German expedition ; thu^ indelible records of the variations will be obtained Atmosphekio Elkctkkitv. The observations for the quantity of electricity present in the atmosphere will Ijc made by means of Lord Kelvin's portuallv as well as photographically. Obser- vations with Aitken's dust counter will also be attempted. In the case of temperatures on shore, platinum ther- mometers connected electrically with the interior of the hut will be used, both embedded in the earth and iec if possible, with one also in the thermometer screen ; by this means the necessity of leaving the hut to read the thermometers when the climatic conditions are dangerous will be avoided. Should the expedition bo able to reach McMurdo Bay for the establishment of the shore observatory, it is highly probable that the low-pressure belt girdling the Antarctic would be passed, and that the conditions would be more favourable for wintering if the anti- cyclonic area over the South Pole exists. At all events it was the east-south-east winds which caused an iii- vaiiable rise in temperature as recorded nt Cape Adare by the " S(uitheni Cross " expedition. 0CE.\N0(:HA1>HY. It is proposed not to carry on deep-sea observations on board the German ship to a greater depth than 1000 metres, but in this country it was thought advisable to go to iiiuch gieater depths, and consequently the • Discovery " has been equipped for sounding and dredg- ing to such depths as are likely to be met with. Ono of the tilings of first importance is to determine the origin and direction of movement of the great ice barrier, and everything that is feasible will be done to sccui-e this. Soundings will of course be made as near as possible to its face, in order to determine whether or not it rests upon the bottom. For the collection of specimens various drag and tow nets will be employed, and for the collection of samples of sea water (for the determination of its physical pro- perties) in which such specimens exist, the Pettersson- Nansen insulating water-bottle will be used. On the voyage out some studies of phosphorescence may be' made, and here the w^ork of the physi- cist and biologist will be united. For the study of oceanic circulation observations will be m^de on the salinitv of the water from various depths. 121 KNOWLEDGE. [JCNE, 1901. as well as upon the temperature determined by deep- sea thermometers. Observations of waves will also be attempted, the article for the Antarctic Manual on this subject being written by Captain Wilson-Barker, R.N.R., some of whose results on wave observations are given by Mr. Cornish in Knowledge for May (page 97). Obsei-vations of the tides will be of extreme im- portance, for it is in the great southern ocean that the tidal systems of the earth have their birth, and here may- lie the tidal effects are more approaching the state that would exist were the globe entirely covered with water. The prediction of tides by applying various factors for local conditions to the theoretical conditions of attraction is a problem of no mean order. There are many other problems to be attacked, but it is beyond the scope of the expedition to do all that might be of interest. But among the many things that may be attempted if time and circumstances pennit, is the study of the variation of carbonic acid in the atmo- spheie. Determinations of the amounts of this gas in the air of regions devoid of vegetation would be of high importance in testing Schloessing's theory of glaciation. Another series of observations which might be made, should the expedition not return previously, are those in connection with the total eclipse of the sun, Septem- ber 20, 1903. The maximum duration of totality is 2|^ minutes, and the central line, although starting in longitude 40° E. and latitude 46° S., does not touch land until it reaches the Antarctic area near the hypo- thetical Termination Is., it then passes over unexplored tei-ritory, and leaves the earth somewhat south of the volcanoes Erebus and Terror. ON THE AUDIBILITY OF THE MINUTE-GUNS FIRED AT SPITHEAD ON FEBRUARY 1. By Charles Davison, sc.d., f.g.s. When H.M.S. " Alberta " left Cowes on the afternoon of February 1 with the body of our late Queen, its course to Portsmouth lay to the south of a line of thirty men-of-war, ranging from third-class cruisers of about 2000 tons to first-class battle-ships of 14,900 tons. The ends of the line, indicated by crosses on the map, were occupied by the "Alexandra" on the west, and the " Majestic " on the east, the two ships being about eight miles apart. A shorter line, to the south of the other, was formed by the foreign ships of war and a group of torpedo-gunboats. As soon as the funeral pro- cession left Cowes. about 3 p.m., a gun was fired from the " Alexandra," after which minute-guns were fired from the " Majestic," the other ships taking their time from the latter. Each ship stopped firing as the tail of the procession passed it, thus causing a gradual fading away in the intensity and duration of the reports. As the yachts rounded the " Majestic," the minute-guns were continued from the coast^defences and men-of-wai- in Portsmouth Harboiu-.* I am indebted to the Secre- tai-y of the Admiralty for the information that 6-inch guns were used with blank charges of 7 lbs. large gi'ain powder. The guns, he adds, could not be fired simul- taneously, but several were fired practically together, which would account for the reports occasionally sound- ing louder. During the days succeeding the Funeral, many letters or abstracts of letters appeared in Nature, the Times, the Diiilij News, and especially in the Standard. The editors of the last two papers and of others published * Most of the above details are taken from the admirable account which appeared in the Times for FebruarT 2ud. in the southern and midland counties kindly inserted requests from nie for notes of observations. The total number of records from all sources at my disposal amounts to 97 from 84 places. These places are repre- sented by dots on the accompanying sketch-map. There are also others, indicated by small circles, where, so far as known, not a single report was heard. The circular arcs are drawn with the position of the " Majestic " as centre, and radii of 40, 60, 80, and 100 miles. Most of the distant records of the minute-guns are un- usually trustworthy, owing to the regularity of the dis- charges and the peculiar character of the reports. As a rule, a loud boom was heard, due to the nearly simul- taneous discharge of several guns, followed by a rumble, lasting in some places for twenty seconds, as ship after ship along the line uttered the note of mourning. From east to north-west, the places where the sounds were heard are scattered fairly uniformly between the 60 and 80-mile circles. Beyond the limit of the latter circle, they diminished rapidly in number, except in the neighbourhood of Cheltenham, where one newspaper editor, less sceptical than others, published my request for information. It should be mentioned that some of the most interesting accounts which appeared in the daily press were so far curtailed as to omit distinct reference to the minute-intervals ; among this group being the records from Shelford (near Cambridge, 111 miles from the " Majestic "), St. Ives (Hunts., 118 miles), and Holme (near Peterborough, 125 miies). But there can be no doubt in this respect as to the observations from Northleach (82 miles), Kingham (near Chipping Norton, 84 miles), Egginton (near Leighton Buzzard, 84 miles), Moreton-in-Marsh (90 miles), Bishop's Cleeve (near Cheltenham, 93 miles), Alderton (near Winch- combe, Glos., 95 miles), and Alderton (near Woodbridge, Suffolk, 139 miles). At several places the vibrations were occasionally strong enough to make windows shake. This occurred at Lingfield (56 miles), Sutton (58 miles), Wallington (58 miles) and Richmond Hill (61 miles), in Surrey; at Tunbridge Wells (65 miles) and Hayes (66 miles) in Kent; at Ashford (55 miles) and Pinner (67 miles) in Middlesex; and at Great Missenden (69 miles) and Ludgershall (77 miles) in Buckinghamshii-e. While the soxtnd-waves were thus heard at great distances, it is remarkable that in the immediate neigh- bourhood of Spithead they were almost or quite in- audible. The nearest place to the " Majestic " from JrxE, 1901.] KNOWLEDGE. 125 which I voceivecl any record is Horloy iu Surrey, distant 50 miles. It does not of course follow that reports A-cre never heard at a less distance, for most pereons so situated would imagine their observations to be of little consequence, but the undoubted fact remains that many who went out to listen to the guns returned home dis- appointed. Thus, one correspondent, who was on a steamer just outside the line of battle-ships, could hear only the reports from the vessel neai'est to him. At Ports- mouth, the lii'st signal that the procession was approach- ing the liarbour came from a gun fired from the ■' Victory." which is stationed there; for even the sound of the guns on the coast defences were scarcely audible in the town. It is said that not a report was heard at Chichester (15 miles from the nearest battleship). Mid- hiu^t (22 miles'), Winchester (20 miles),! Fritham Plain (2 miles N.W. of Lyndhurst, 16 miles), Newbui-y (44 miles). Bournemouth (27 miles), and Yarmouth (I.W., only 10 miles). There can be little doubt, I think, that the varying direction of the wind over the southern half of England is mainlv responsible for this curious result. If there were no wind, and the temperature were uniform, the sound-waves from any gun would be spherical and the sound-rays rectilinear. If the velocity of the wind were uniform throughout, this would also be the case, though the sound would be heard slightly further iu the direction towards which the wind is proceeding than iu the other. But if, as usually happens, the velocity of the wind increases with the height above the ground, the sound-rays are no longer rectilinear. Those travel- ling in the du'ection from which the wind is coming are bent upwards, while those travelling in the same direction are bent downwards. In the former case, the sound-rays pass over the heads of observers at a moderate distance ; in the latter, rays which started upwards at a small angle are brought down again to observers at a considerable distance. They are thus audible at much greater distances than if there were no wind, and be- sides travel as a iiile along unobstructed paths. Xow, on February 1, the wind at places to the west of Spithead was generally light and from the west or nearly so, though near Lyndhurst there was a fresh breeze from about W.X.W. or X. \V. At Portsmouth, again, the wind is described as from the shore. On the other hand, many of my correspondents at great distances from Spithead state that the wind, when sensible, was southerly in direction. Thus, the sound-rays were first of all refracted by contrary winds over the heads of observers between 10 and 45 miles, and were afterwards brought down again by favourable upper currents, so that the reports were clearly audible beyond 50 miles and up to 140 miles from Spithead. and were so loud at a distance of 84 miles that labourers in the fields put down their spades and listened. ♦ FLOWERING PLANTS, AS ILLUSTRATED BY BRITISH WILD-FLOWERS. P.V R. LlijYD PR.A.EGER. B A. III.— FLOWERS. Having briefly considered the uses and the architecture of the roots, stems, and leaves of plants, we now come to examine the floral structures. Here we find an elabora- tion of design, a wealth and variety of shape and colour, a specializing of organs to meet peculiar requirements, which must strike with admiration the most casual + 'Winchester lies in a hollow ; and, at other times, guiu ai'e. T am informed, often heard ujion the Downs while they arc inaudible in the city. observer. The roots and leaves which wo have been considering have for their main object the contributing to the success in life of the individual, and only in- directly, according as they minister to the life and health of the individual, do they in most cases contribute to the continuance of the race. Flowei-s, on the other hand, are especially concerned with the life of the race, not of the individual. ' If we cut off every blossom of a plant before it reaches maturity, the health of the plant will be in nowise injured; but seed will not be pro- duced, and carried to its ultimate limit, such practice woidd eventually lead to the extinction of the species. Wo now begin to see why plants (so to speak) indulge iu such an elaborate exjjenditure of care and ingenuity in the designing of their (lowers — the hope of future genera- tions rests in these delicate and marvellously beautiful structiu'es, and on their success in carrying out their appointed part in the production of copious and perfect seed. For our present purpose, the essential nature of a flower may be brojuUv defined in a very few words. A flower is a gi'oup of modilied leaves, of which the essential parts consist of male and female elements, the male element consisting of pollen-pcoduciiig organs, while the female consists of the young seed and its accompany- ing stractures. The male organs, or stamen, at the jjroper time liberate grains of pollen, which on reaching the receptive surface of the female organs, grow dow^n into the embryo, or young seed, and the union of these elements is followed eventually by the production of perfect seed. Surrounding these essential organs there are generally other leaves, of very varied shape, size, colour, and number — the sepals and petals. The function of these is largely protective, and often attractive ; some- times, as we shall see, repeUaut; and it is to these protean outer portions of fiowers that our attention will be mainly directed. Xow. although a large proportion of flowering plants produce male and female organs in the same flower, it is generally essential for the pro- duction of fertile seed that each flower should be ferti- lized, not with its own pollen, but with the pollen of another flower — that cross-fertilization should be effected. This implies the transfer of pollen from one blossom tn another : and in the manner in which this transfer is effected we have the key to the mysten' of the infinite variety of shape and colour that we find iu flowers. To begin with a simple case. The flowers of gvissc^ consist each of several small chaffy green leaves, which enclose the male and female organs. The flowers are usually arranged in little groups, each group foiTning part of a large branched colony of flowers, or iufloic-- cence ; each individual flower is small and inconspicuou'. The function of the outer parts of the flower is purely protective; they keep the essential portions warm^and dry, and safe from the attacks of animal enemies. While the outer portions are thus minute in size, the essential portions — tiie stajnens, and the receptive portion of the female organ, or .«//ctive, were enlarged and coloured, till they became highly conspicuous ; and scent was produced, of various sorts, according to the kind of insect visitor which it was intended to attract : and by degrees a very high degree of specialization has been attained. Let us take a few instances. In otu- common Buttercups the outermost whorl of flower-leaves, or culyi. is gi-een, not very large, tough, and hairy. It safely encloses the whole blossom tiU the latter is ready to burst open, keeps it warm and dry, and provides a defensive armoui" against nibbling insects. When the blossom expands, the calvx in some species falls off, its duty completed ; in other species it remains. The next whorl, or cnrolhi. is composed of brilliant yellow petals of considerable size and wondei"ful lustre, which render the flower in the highest degree con- spicuous. These petals have a protective as well as an attractive function, for at night, or in i-aiuy weather, they close like a hood over the inner essential portions of the flower, and protect them from cold and wet. opening again as soon as sunlight comes, and insects are on the wing. The numerous poUen-bearing organs, or stamens, are arranged in a ring inside the corolla, and in their turn surround the female organs, which, in the form of numerous separate carjie?x. are set on a kind of cushion in the centre of the flower. An insect visiting such a flower alights inside the cup-shaped corolla, and as it turns' about in search for honey (which is secreted near the base of the petals and stamens) it rubs the under-stu-face of its bodv against the upper receptive portion of the carpels, depositing thereon some of the pollen which it has presumably picked up in visiting another flower previously, at the same time dusting itself with the pollen of the flower which it is now engaged in plundering. This general description will apply with slight modifications to a large number of our wild-flowers and their mode of fertilization — for instance, to our Stitchwoits. and Wild Roses, and St. Johns- worts, and the manv Umbelliferous plants, but it will be seen that even in these flowers there is a considerable waste of pollen and honev. Both lie open to all comers. The honev mav be stolen bv small insects which do not fly from flower to flower, but have crawled up the stem, or by others whose minute size allows them to get at the honey without disturbing or touching the anthers or stigmas. And. again, both pollen and honey lie exposed to the weather. In irregular flowers, such as the Peas and Vetches. Snapdragons. Deadnettles. and Orchids, we find a much more specialized flower-strticttire. The fiowers. instead of being cup-shaped, with their entrance vertical, are of various peculiar shapes, and have their entrances hoiizontal. Examine the blossom of the common Gorse. One large showv petal extends hori- zontally across the top of the flower, forming a protective roof. Two smaller ones stand vertically one on each side below this. The remaining two petals form the bottom of the flower, iiiid are joined by their lower edge so as to form a boat-shaped structure. The gioup of long ciu-\e(I stamens and pistil lie along the bottom of this keeL The pollen is shed, in part at least, before the flower attains maturity, and falls into the bottom of the keel. A suitable insect, say a bee, visiting the flower, is bound, owing to its peculiar shape, to alight on thekeel. Its weight, by depressing the keel, causes the tip of the stigma to slide out beyond the end of the keel, pushing before it some of the fallen pollen, and both come in contact with the tinder side of the bee s body. It is clear how much more certain and economical this device is than the lavish scattering of pollen carried on by the Buttercup. And here we notice a discrimina- JtNE, 1901. KNOWLEDGE. 127 I loii on tlic plant s part betwoen >uital)K- and un>uitalilo insects: a fcatnr,; which becomes loniaikablv dcvelojied m many of the more higlily specialized tlowcrs. Tlicv cannot afford to give honey and to dust pollen on every vl^ltor ; and along with an-angcnient.s made to suit welcome insects may be found picuous effect produced (1) by great enliirgement of the corolla (Co«ro/t'«/Ki), and (2) by the grouping in a larije umbel of numerous smaller llowers (Angelica). Phnlo.j.aph ',./ U. Welch. find an ingenuity of design, and a wealth and variety of form and colour, that ai-e unequalled in the vegetable kingdom. Some of the common Orchids of our meadows will exemplify their structure quite as well as the most gorgeous Brazilian species. Examine one of our common British Orchids, .such as On-hix wnciihifn or HaliiiKiria hifolia — they are just coming into bloom now. The calyx consists of three sepals, the corolla of three petals ; all are colour-id similarly, but dift'er in shape. It must be pointed out that these flowers, when mature, are all upside-down, as we may see by opening a bud, and com- paring the relative positions of the parts with those of an open flower. This inversion of the flower is caused by a twisting of the ovary, or seed-vessel, which is long, and looks like the stem of the flower: this twisting also we may observe by comparing the ovaries of a bud and of an open blossom. The large petal which, in the bud, is topmost, and folds over the other portions of the flower, in the open blossom is lowest, and forms a broad landing-stage. Two sepals stand one on either side ; two petals and the remaining sepal form the roof of the flower. The lowest petal is prolonged backwards 128 KNOWLEDGE. [Jul 1901. into a deep uanow lioney-well. So far the flower re- sembles 111 inauy respects that of the Salvias described above. But when we look for the stamens and pistil we find an extraordinary structure. The pollen-grains are fastened together into two oblong bundles by means of slender thi-eads, and each bundle is prolonged into a delicate stalk, the tip of which is enlarged and coated with viscous fluid. The whole is embedded in the wall of the flower, over the honey-well, and facing the entrance, and the sticky termination of the stalk alone is exposed. The stigma is likewi.se embedded, and shows a sticky surface below the position of the stamen. How does this structure work? A bee alights on the platform and pushes its head into the entrance to the tube. Its forehead comes in contact with the sticky extremities of the embedded pollen-masses, and on withdrawing, it pulls one or both of these out of the grooves in which they rest: the bee flies off with the pollen-masses sticking on its foi-ehead like two horns. And now a remarkable thing happens. Owing to unequal shrinkage caused by drying, the stem of each pollen-mass curves, so that instead of standing upright they now project forwards. In consequence, when the beo visits another flower, and inserts its head, the pollen-masses come in contact, not with that part of the flower which encloses the pollen, but with the sticky stigmatic surface below, and thus fertilization is effected. The absolute accuracy of the method, the economy of pollen, the way in which the plant is entirely dependent on the visits of the right kind of insect for its fertilization, show that here we have reached the very acme of specialization iu this direction. It is to be noted that along with the modifi- cation of the plants to suit insect-visitors, considerable modification in the structure of the insects has taken place to suit their honey-sipping habits, so that now many are as dependent on the flowers for their food, as the flowers are dependent on insects for their fertili- zation. There is a complete symbiotic interlocking between the representatives of the animal and vegetable kingdoms. It is the most highly organized plants that lay them- selves out to attract the most highly organized insects. Simply-constructed flowers like the Buttercups and Um- bellifei-s, which have their honey and pollen openly exposed, are visited by a motley crowd of flies, beetles, ants, and other insects, and these flowers are largely yellow or white in colour. With more specialized flowers come preventive measures, and the encouragement of certain groups of winged insects ; while the most highly developed flowers lay themselves out exclusivelv for the attentions of the aristocracy of the insect world — the bees, butterflies, and moths ; and from the simple yellows and whites of the lower flowers they turn to the richer tones of red, and purple, and blue. CONSTELLAT*ON STUDIES. By E. Walteh M.\under, f.r.a.s. VI.— THE SWAN AND THE EAGLE. One feature of the primitive constellations, whatever its significance, cannot escape the most casual notice. Many of the forms, indeed most of them, are duplicated, and when thus repeated the twin symbols are, as a rule, not widely separated, but placed close together. The portion of the sky to which we have now come is tlie home of the birds. Here, Ai'atus tells us, " Tliere is in front another .Arrow ca-st. Without a bow ; and bv it ilics tde Bird Nearer tlie north. And nigh a second sails Lesser in size, but dangerous to come From ocean when night tlies; the Eagle named." In the midnights of early June, the great stream of the Milky Way crosses the sky from due south to due north, not j^assing, however, through the zenith but somewhat to the east of it. Right in the centre of this magnificent arch, forming its very keystone, is the constellation of the Swan, easily found from its neigh- bourhood to Vega, Alpha Lyrae. The figure of the " Bird,' or as we now know it, the '' Swan," may be easily traced out. A long undulating line of bright stars lies parallel to the axis of the Milky Way, skirting the western edge of the great channel which here divides it. This represents the outstretched neck, body, and tail of the flying Swan. Crossing it at right angles, is another undulating line of stars which repre- sents the outstretched wings of the flying bird. The whole constellation has often been termed from its shape the '' Northern Cross." Beta Cygni marks the extreme tip of the Swan's bill, and lies about as far beyond Gamma Lyrae as Gamma is from Vega. Its name is usually given as Albireo, but the meaning and derivation of the word is obscure, and is almost certainly due to a mistake. The Arabic name is Al minkar al dajajah, the " Hen's Beak." It is one of the loveliest double stars in the entire heavens ; the principal star, of the third magnitude, being topaz yellow, the com- panion, of the seve^nth magnitude, sapphire blue, and the distance, 35", being within the power of a field-glass. Gamma, the bright star which marks the intersection of the cross, is the centre of a most interesting region. The whole extent of sky from Beta to Gamma is perhajjs the richest in the entire heavens, and Gamma itself is in the midst of rich streams of small stars, interspersed with some strikingly definite dark lanes. Of the transverse beam of the cross, Ejasilon marks the eastern arm, Delta the western, and from Gamma to Epsilon we find one of the most remarkable gaps in the Milky Way, the " Coal Sack," Alpha has been called Deiieb Adige, the " Hen's Tail," or Aridif, the " hindmost " or " follower," both titles appropriate enough to its place. The entire region of the constella- tion is full of interest and beauty, whatever the optical power with which it is examined, from the naked eye up to the greatest telescope. One of the many intei'est- ing objects in the region is Omicrou. To the eye a double star makes a trapezium with Alpha, Gamma and Delta; the brighter of the members of this double, Omicron, in the field-glass will be seen to have two com- panions, one on each side, both of them blue, whilst the chief star is orange. Aratus gives the constellation simply as the " Bird," without naming its species, but Eratosthenes defines it as the " Swan," and its length of neck well agrees with the identification. Dr. Lamb's somewhat doggerel rendering of Aratus enlarges upon his author in this connection to bring in absolutely without warrant the story of Leda and Zeus. The second bird is, how- ever, plainly identified as the Eagle, and its chief star, Altair, fomis the third point of a roughly equilateral triangle, the other two angles of which are marked by Vega and Alpha Ophiuchi. It is also easily identified by the two smaller stars. Gamma and Beta, above and below it ; these making with it a characteristic figure of three bright stars in a straight line, on the borders of the Milky Way. The three stars bear the following names: — The middle one. Alpha, is Altair the "Bird," that is the " J''lyer " ; the " Soaring Eagle," as con- trasted with Vega, the '' Swooping " or " Falling Eagle "; the southern star is Beta, Alshain, the " White June, 1901.] KNOWLEDGE 129 Falcon '" ; and Gamma, the northern stai-, Tai-azed the ■ Robbing one. " The rest of the constellation can be made out without much trouble, but the figure is by no means so good as that of Cygnus. Two stars, Zeta and Epsilou, near together, mark the tip of one wing in the north-westerly direction, and a veiy much fainter pair. 70 and 71, mark the tip of the other wing, about the same distance on the other side of Altair. Proceeding from Gamma down the Milky Way, we find Mu. Delta and Lambda, reproducing roughly the arrangement of stars which to that in which he is shooting. This is the explanation of the phrase — " Another Arrow cast W^ithout a bow ; " nor can either of the three heroes, who are near at hand, tlie Herdsman, the Sorpcnt-holdcr, or the Knecler have despatched it. The Herdsman grips his crook, the Scrpcnt-holder has both hands full of the twining snake, and if we accept the guess of Panyasis that the Knecler was really Hercules, Germanicus tells us that one hand held a club, the other a lion's skin. Parallel to the Arrow, and of not much larger extent. \\m IXX . XY XIX IIIAX IIAX lAX AX -;*"t .. CEPHEUS •il ..V \ DRACO CY&NUS, . , _ _..',T . - ,1^ e ' • V •r I j i •A V '32 ^ .-: ,r LYRA 13 n ■a / / , . BOOTES ■\ • \ • • >. ^r » ^ CORONA •P PEOASUS < VULPECULA \^. — .. _^ .' DELPHINUS I • 5 '«S 109 s ' PHINUS \ :.,«^ ,J -- ^4 •"» ^\X. !SA&1TTA^ ^^..•«' I •s HERCULES •0. \-- 'serpens I /serpens \ i K / \ •! ^^. *■ T AQUARIUS •0 -^■m m wi Mil Ig [in \%% m~ AQUILLA -i \ 41 OPHIUCHUS I'f .> A» ♦ ^ :^ XXII XXI XX XIX XVllI Star Map No. fi ; The Region of Cygnus. XVII XVI marks so clearly the neck and head of the Swan. Fol- lowing the line of the three stars. Alpha, Beta, Gamma, we find they point downwards to a bright star, Theta ; between this and Delta, but nearer to Theta, is Eta, one of the regular variable stars of short period, visible in all its phases to the naked eye, its period being one of four hours over the week. The quotation from Ai-atus at the licad of this paper refers to a little constellation which in a certain sense is the most interesting in the entire sky, the constel- lation of the Arrow. Possessing only five little stars of the fourth magnitude, and extending in a narrow line, but 4° in length, increased by the moderns to 10°, it is nevertheless one of the oldest constellations, being mentioned three times by Aratus in his celebrated poem, and having its five principal stars duly cata^ logued by Ptolemy. The history of the Arrow was lost even in the time of Aratus. It was not shot by Sagittarius the Archer; so much is quite clear, for it is flying high above his head and in the opposite direction is the modern constellation, Vulpecula. framed by Hevelius in 1690. Its principal interest to the naked- eye observer is the meteor stream which radiates from it in the latter half of June, and to the telescopic ob- server the celebrated Dumb Bell nebula, just visible in the field-glass. A line from Alpha Ophiuchi through Zeta Aquilae, and another from Alpha Cygni through Epsilon Cygni, will meet together in a pretty little con- stellation, which, once picked out, can never be for- gotten, its leading stars being so nearly equal in mag- nitude and so close together. This is the constellation of the Dolphin, containing ten stars in Ptolemy's cata- logue. Two of these are a little brighter than the fourth magnitude, and seven others range frojn that down to the fifth. Alpha, Beta, Gamma and Delta form a com- pact little lozenge, the straight line of Gamma and Delta being continued on by Zeta and Epsilon. Though the Dolphin is one of the ancient constellations, the names attached to the two principal stars arc quite modem, and are due to a piece of very clumsy humour 130 KNOWLEDGE. [June, 1901. on the part of Piazzi, the Sicilian astronomer. In his catalogue he introduced for these two stars the names 'Si »i' AURIGA URSA CVGNUS w lYSA t- . VULPECyiA . . ae ^oi^' DftPHINUS SflCiTTA V CAPmCORNUS ftQUILLA « ^Serpens f 9 ' SERPENS OPHIUCHUS f * SACITTAItlUS- ■''Sg&.i.-^. 3.- w *' LIBRA The Midniglit Sky for London, 1901, June 2. Rotanev and Svalociu, names which gave a good bit of trouble to etymologists until it was seen that they were simply the name of Piazzi 's assistant Niccolo Cacciatore, latinized and spelt backwards. NEW STARS. By the Rev. A. L. Coetie, s.j., f.e.a.s. The appearance of the brilliant star in the coniteilation Perseus, discovered by the Reverend Dr. Anderson, of Edinbin-gh, in the early morning of Februai-y 22nd. has naturally awakened the keen interest of astronomers in the subject of the origin and composition of such bodies. In the twenty centuries that elapsed between the years B.C. 134 and a.v. 1892, when the last new star visible to the naked eye, previous to the advent of the present stranger, was also discovered by Dr. Anderson, only nine- teen cases of such appear-inces have been recorded. Another six, of small magnitude and invisible to the unaided eye, appeared on the photographic plates secured in the period 1877 to 1899 by the indefatigable director of the Harvai'd College Observatory, Professor E. C. Pickering. Of the first new star known to us by historical records, we learn the bare fact that its discovei-y was due to Hipparchus, and the interesting statement of Pliny that it suggested to the Greek astronomer the construction of a catalogue of stars, the earliest that is extant. Of the other new stars discovered before the general adoption of the spectroscope and photographic plate as powerful auxiliaries of the telescope, the most famous was Tvcho Brahe's star, which blazed out in the constellation Cassiopeia in the year 1572, and was visible for a year and five months, rtvalling at first Venus and then Jupiter in brilliancy. Of this star it is recorded that its colour changed from white through yellow to red, and then to white again, thus furnishing some indication of a probable fluctuation in and recuperation of its light, phenomena which have been also marked in succeeding new stars. Another Venus-like star was tliat observed bv t.Iie famous Kepler in a.d. 1604, and visible for a year. The brilliancy of this star joined to a conjunction of the planets Jupiter, Mars, and Saturn in the same part of the heavens led the illustrious astronomer to propound the theory that it was a similar phenomenon which appeared to the wise men in the East and led them to Bethlehem. The same century witnessed yet another outburst, in the year 1670, this time near the star/3 C3 gni, the detection of the star being due to the Carthusian monk Anthelmus. This star was visible for two years, and likewise exhibited fluctuations in its light. The century just completed was marked by five such apparitions, namely : in 1848, w-hen a star was discovered by Dr. Hind in the constellation Ophiuchus ; in 1866, when a star in the Northern Crown blazed up suddenly from the ninth to the fourth magnitude, and after again increasing its lustre six-fold in about six hours, finally became a variable; in 1876, when a star of an orange-red tint appeared in the constellation Cygnus, which attained a lustre equal to that of a third magnitude star, and' which when observed by Buniham at the Lick Obsei-va- tory in 1891 was a small star of 13. .5 magnitude, and " at times seemed to resemble an exceedingly minute nebula"; in 1885, when a star appeared in the very heart of the Andromeda Nebula; and finally in 1892, \\hen Nova Aurigae was discovered. On the appearances pi'esented by this star it will be necessarj- to dwell some- what in detail, as it marked a considerable advance in our knowledge of the varying ijhenomena of such tem- porary visitants. It was certainly not of the eleventh magnitude on December 8th, 1891, otherwise it would have impressed its image on the photographic plates of that portion of the sky taken by Dr. Max Wolf of Heidel- berg. Two days later it was on the plates taken at ITaivard College, and was of the fifth magnitude. It attained its first maximum of 4.4 magnitude on Decem- ber 20th. It then decreased slowly in brightness with slight fluctuations until January 20th, 1892, when it was somewhat below the fifth magnitude. It was first seen, and discovered by Dr. Anderson, for its prior history by means of the photographs was only elucidated subse- quently to his announcement, as a fifth magnitude star on January 24. After this it received another access of lustre and attained a second maximum of between the third and fourth magnitude on February 3rd. It then staadily grew fainter, with the exception of another slight rise in magnitude between March 16-19, until at the beginning of April it was equal to a faint thirteenth magnitude star. On April 24th the Lick observers estimated its magnitude as sixteen. But in August of the same year, it again recuperated its energies, rising to the ninth mag- nitude, or increasing in brightness nine hundred fold. There occurred, therefore, in this star a sudden out- burst, a rapid rise to brilliancy, a fall, another rise to maximum brightness, again a fall, a third rise, tliough less brilliant tlian its predecessors, and then a rapid and persistent fall to extreme faintness. But four months after, it became an easily discernible telescopic object, its haziness of outline suggesting that it too had become a nebula. With regard to the nova of the present year, although the observations have not yet been completed, we notice a similar sudden burst from a low to a high magnitude, at least 12i magnitudes in three days, corresponding to a 100,000 "fold Increase in its light, a similar gradual de- cline with fluctuations of brilli-ancy, so that at the end of March the star seemed to have become a variable with a period of three days. The nova of 1866' was the first new star the light of PHOTOGRAPHS OF THE SPECTRA OF NOVA PERSEI AND PROCYON. STON YHU KST ( '( ) f J. KG K () HH K I! V A 'l'( ) 11 V . 1.— I911I, .\r:civl, :inl. s p.m. 2.^M:ircli L'lst. H). p.n,. 3— Marrli 2.".tli, S'. |j.iii. ■luxK, 1901.] KNOWLEDGE. i;u whicii was subjected to the analysis of the spectroscope, (lie earliest observations being those of Sir William Mugf'iup and Dr. Miller. The chief facts observetl with regard to its spectrum were that it was compound, being composed of two series of bright and dark lines, super- posed u])on a background of continuous spectrum, and tliat the bright hydrogen lines predominated. jM. Cornu called attention to the matching of the brightest lines in tho stai's spectrum by well-known lines seen bright in (he chromosphere of the sun. With regai-d to the spectrum of Xova Cygni in 187G, Professor Vogcl called attention to the extent of the spectrum which stretched far into the violet regions, the double spectrum of bright and dark lines, especially those of hydrogen, and the gradual changes in the spectrum, winch had become reduced to a single line in the green, very near in position to the chief line characteristic of nebuise, when the star had fallen to the t«nth magnitude. The spectrum of Xova Andromeda in 188.^ was mainly continuous, being similar in this respect to the spectrum of the first days of Nova Persei, ajid, moreover, confined to the green. The spectrum of Nova Aurigje was the first which was permanently recorded for future comparison and study by means of the photographic plate. It was a very wonderful spectrum, with many new details of its own, but still confimiing all the earlier obsei^vations of the spectra of novar. The compound or double spectrum of bright and dark lines was very striking, the more intense bright lines, especially those of hvdrogen, being accom- panied on their more refrangible sides by broad dark companions. The line near the position of the chief nebular line was very marked. The spectrum, too, was of great length, extending from beyond C in the red right down to the further limit of the ultra-violet. It was full of lines, the Stouyhurst photographs, which comprised the region from D in the yellow to H in the violet, show- ing more than 200 lines. Many of these lines, too, were of gi'eat breadth, notably those of hydrogen, extending over several tenth-metres, or units of wave-length. On an average the centres of the dark absorption lines were about 11 such units removed from the most intense points of the bright bands. The match, too, both in character and position of the lines in the spectrum of the star, and in the spectrum of the sun s chromosphere was very evident. Moreover, sharp bright lines appeared on the dark bands after the star had attained its maximum. Such an appearance is not unknown in the spectrum of sun-spots, and on the calcium lines H and K, in the solar spectrum. Lastly, when the star received an accession of light in the August of 1892, the spectrum as examined by Professor Campbell, of the Lick Observatory, was strikingly similar to that of planetary nebulae. The beautiful photogi-aphs of Nova Persei by which we are enabled to illustrate this paper, through the kindness of Father Sidgreaves, were taken on March 3rd at 8 p.m., on March 21st at 8.30 p.m., and on ilarch 25th also at 8.30 p.m., by means of an objective prism of about 4 inches aperture, made by Mr. Thorp, and fixed to the finder, also of the same aperture, made by Cooke & Co., of the 15-inch equatorial. A spectrum of Procyon is placed below the spectra of the nova to show the posi- tions of the hydrogen lines or rather bands Reading from right to left they are H/3 to Ht. the calcium line K, immediately following Ht. Without entering into any details these photogiaphs sufficiently illustrate the chief points to which we have directed attention in the spectra of all novae. There are many other matters worthy of study, but beyond the scope of the present paper. There is. however, one fact with regard to the chanjres in the spectrum noted in Nova Persei, which deserves mention, as it has never been observed before. It is that when the spo.-trum was photographed at Harvard, and observed at Kdinburgh on tiic nigiit of February 22nd, it was con- tinuous and crossed by only thin dark lines. By Feb- ruary 24th the bright linos were well in evidence with their dark companions. Tills would seem to point to a sudden raising of the temperature of a dark solid cold body to a white heat. Then came absorption by the vapours thrown off, giving the dark line spectrum so well known in the sun and in the stars of the Orion type, and then the supremacy in radiative power of the gaseous s]/cctrum .suddenly asserted itself, and became the chief feature, as is the case in those storms on the sun which we call spots and prominences. How then are we to account for the origin of such stars? At the outset wc must frankly acknowledge that the appearances are extremely puzzling, and that so far no theory has been broached which satisfies all the con- ditions of the pioblem. For any theory of a new star's origin and constitution must needs find an explanation for the sudden outburst of light, for its fluctuations in intensity, for the complicated spectrum, its extent, its multitude of lines, the phenomena of the bright lines and their d.ark companions, together with their e.xceeding great breadth. But the crucial jjoiiit of the whole problem lies in the fact that this shifting is always in the same direction, of great extent, and persists for a long time. I fancy any theories that purport to explain the appearances on the supposition of the motion either of meteors through a nebula, or of a cold dark body through luminous particles, must needs satisfy, first the enormous velocities of the moving bodies in the line of sight, some 500 miles a second at the least, if indeed the displace- ments observed are due to motion in the line of sight, the persistence of such velocities for months, and, most difficidt point of all, their invariable occurrence exactly in our line of sight. Should we attribute the great widening of the lines to pressure, after the analogy of the laboratory experiments of Humphreys and Moliler, and of Wilsing, we do not escape the difficulty of the long per- sistence of such pressure, to say nothing of its enormous amount. However, we note that the light curve of new stars is very like the curve of sun-spot frequency, with the rapid rise to maximum, and the fluctuations as the ener- gies displayed in the initial stages of the outburst are gradually expended. Next the spectrum of new stars is in the main the spectrum of the solar chromosphere, at least in its earlier stages. Moreover, appearances very similar, though on a greatly reduced scale, to the double spectrum of new stars can be observed in the spectra of sun-spots and prominences. And it must be bcrne in mind that a sun-spot is only one of the forms in which the forces in the sun are displayed. For a sun- spot is always accompanied by prominences, as also by faculae at times of vast extent. It is true that in the chromosphere the lines, except at their bases, are very thin, showing that the pressure cannot be very great; but in spots the lines are widened, due no doubt to the density of the matter composing them, and, moreover, frequently shifted, perhaps the partial result of pressure. We have already alluded to the reversals to be seen so frequently in the spectra of spots and prominences, and, moreover, binds have been observed in the spectra of the former. But in spite of all those similarities we cannot claim them as anything more than suggestive of the pos- sible lines on which the problem as to the origin of new stars is to be attacked. 132 KNOWLEDGE. [June. 1901. Astronomical.— The observations of the total eclipse of the sun on May 18 th ap]iear to have been only partially sucL-essful. lu S\imatra the conditions were very uufavoui'able, althouirh iii)t bail enough to completely obscure the sun. We gather that the Dutch astronomers succeeded in obtaining photographs both of the corona and spectra, but the jnismatic camera did not succeed. At the time of writing there is little news from the British observers in Sumatra, but it has been reported that the duration of totality was six minutes twenty-one seconds. In Mauritius, where Mr. and Mrs. Maunder were stationed, the total phase appears to have been well observed. Fifty-two photographs of the corona and eighteen photographs of the s[)ectruni were taken with the various instruments. The corona was of the expected minimum tyjje. Prof. Campbell has recently utilised the spectro- scopic results obtained at the Lick Observatory for an investigation of the sun's motion in space. The conclusion is that the sun is approaching a point in ~R A. 277° 30'. Decl. + 19' 58', with a velocity of i;»-89 kilometres per second. Tliis velocity is considerably smaller than the average of the 280 stars on which the calculations are based, and Prof. Campbell further con- siders that there is evidence that the faint stars are moving more rapidly than the bright stars, and therefore that they are relatively further from us than the investigations of their proper motions have led us to conclude. Through the generosity of Mr. Mills, Prof. Campbell will be enabled to extend his researches so as to include stars invisible at Mount Hamilton by establishiug an observatorv in the Southern Hemisphere. Mr. R. T. A. Inues, of the Cape Observatorv, has comnumicated a paper to the Royal Astronomical Society in which he gives_ several instances of stars which have not disappeared instantaneously when occulted by the moon, some of them vanishing in two distinct stages, and others by "gliding." He points out that on several occasions double stars have been detected bv the phenomena attending their occultations, and considers that dis- appearance either in two stages or by gliding is almost certainly due to the star being reallv a binarv^'system. A particularly interesting feature of this mode" of detecting double stars is that the observation can be made with telescopes of very moderate size. Mr. Junes remarks that many of the doubles which may in this way be discovered will be too close for telescopic confirmation, and may therefore form a class intermediate between visual doubles and spectroscopic binaries. Special interest attaches to the behaviour of known spectroscopic binaries, and it is suggested that careful observations should be made of the coming series of occultations of a Virginis. In the course of a communication received from Baron Kaulbars, of St. Petersburg, it is suggested that the fluctuations in brightness of Nova Persei are due to a riog of meteors, of varying density, which surround the star. The idea seems to be that the light is dim when a dense portion of the ring is in front of the star, and bright when a sparse portion is in front. The arrangement appears to be a very artificial one, and it is difficult to understand how it can account for the changes of spectrum. In Harvard Circular No. 58, Prof. Pickering discusses the interesting photometric problems suggested by the variability of Eros. Owing to the varying position of the observer with regard to the planet, it will be possible to gain mucli information which is inaccessible in the case of a variable star. The material already accumulated is under discussion, and the preliminary results will shortly be available for publication. In the photographs taken in 1893, 1894, and 1896 (before the existence "of the planet was known), distinct changes can in some cases be traced ill the brightness of different parts of the same trail. This suggests an easy method of discovering short period variability in an asteroid. — A. F. Botanical. — A curious instance of a root being transformed into a leaf, or, at least, into an organ which apparently possessed all the usual characters of a leaf, is recorded by Professor R. A. Philippi in a recent number of the Berichte der deulschen bofaiiischen Oesellschaft. Professor Philijjpi planted in flower-pots a number of corms of Crocus rernus, which he had received shortly before from Holland. These failed to show any signs of growth above the soil, which was therefore turned out of the pots, when a white piece of root, 12 cm. long and 2 mm. thick, was found attached to a piece of a Crocus- corm. He inserted the conn-end of the root in soil to the depth of 4 cm , and allowed the rest to be exposed to the light. After several weeks, a slightly elevated line was observed on the side of the root which received the greatest amount of light, and this quickly developed into a green, leaf-like body, 7 mm. in width. The function of assimila- tion j)roceeded as in an ordinary leaf. New. roots were formed, and subsequently four normal leaves. — S. A. S. ENTOMOLOGiCAL.^An interesting contribution to the life-history of beetles has been made by Mr. G. C. Champion and Dr. T. A. Chapman, who publish in the Trans. Entom. Soc. London, for 1901 (pp. 1-18, pis. 1-2), some observations on certain species of Orina, an Alpine genus of Leaf-beetles (Chrysomelida;), adorned with brilliant metallic colours. The statement of former naturalists that most of these insects bring forth their grubs in an active state is confirmed ; such " viviparity," unusual in insects generally, is especially rare among beetles. One of the observed species (0. /ci's/i^), however, lays eggs which are subsequently hatched. The most remarkable fact brought to light in this ptaper is that, in O. viHifjera at least, the embryos develop not in the vagina but in the ovarian tubules. Evidently the method of fertilization in these beetles must be exceptional. Father Wasmann describes (Zeits.f. iriss. ZooL, LXYII., 1900, pp. 599 — 617, pi. 33) some remarkable flies — Ternii- toxenia — found in the nests of South African termites (" white ants "). These flies have the hinder segments of the swollen abdomen doubled under, somewhat like the "tail" of a crab, and the thorax is provided with appendages (suggestive of vestigial wings) whereby the insects are lifted and carried aliout by then- hosts. This observation renders it likely that the flies supply the termites with some food-product, despite the fact that the lancet-like structure of their jaws shows them to derive their own food from the bodies of the termite larvfe. They furnish, therefore, an interesting link between the parasitic and the inquiline habit. — G. H. C. Zoological. — In a paper on the musk-oxen of Arctic America and Greenland, published in a recent issue of the Bulletin of the American Museum of Natural History, Dr. 1901.] KNOWLEDGE. 133 J. A. Allen nieutions that tbo first susiirestiou of tho dis- tiuL'tnoss of thoOreonlaiul from tho Anioriiiui form ajipeariHl in Knowledlie. iu the artiole on the vouii'; musk-ox at \Vol>uni. It is true that the autliorof that article, misled l\v some badly-executed photojirajihic reproduetious, did not at that time realize the eoustaney of the distinctive features he I'ointed out as dift'erentiatint; youn^' Greenland musk-ox from the American representative of the sjiecies. But iu his subsequent separation of the Greenland form, on account of its white face-markings, as a local race he has been fully justified by the American material. Indeed, on account of certain differences in the form of the horns and hoofs. Dr. Allen would go one step further, and con- sider the Greenland musk-ox entitled to rank as a separate species, under the name of Ovihog trarJt. In the Ajiril issue of the Procefidiiujs of the Zoological Society of London are published extracts from a letter addressed to the Secretary by Sir Harry Johnston, relative to a hitherto unknown mammal of the aiiproxiniate size of a horse inhabiting the Aruwimi, or Congo, Forest iu the country between Lakes Albert and Alliert Edward. The animal, which is known to the natives as the okapi, was described to Sir Harry as being iron-grey, or dun, above, with the legs and uuderparts striped, and the muzzle greatly elongated. Mention was made of two strips of skin, which iu due course reached England, and were exhibited before the Zoological Society, when the animal to which they pertained was definitely stated to be a new species of zebra. On the 7th of April a coloured sketch of the okapi was exhibited to the Society on behalf of Sir Harry Johiistou. This sketch shows a hornless ruminant with striped legs and uniformly coloured body. And it is suggested by Sir Harry that the new animal may prove to be a. near relative of Helladother/um of the Grecian Tertiary. Be this as it may, the discovery promises to be one of the highest importance, and the description of the specimens reported to be on their way to this country will be awaited with interest. Hctttrs. [The Editors do not hold themselves responsible for the opinions or statements of correspondents.] STELLAK PAEALLAX. TO THE EDITORS OF KNOWLEDGE. Sirs, — -As is well known the moon, although it revolves round the earth, does not describe a circle in space but a curve of double ciu-vature, because as it revolves round the earth, the earth travels along its orbit round the sun ; but the sun is travelling at a rapid rate towards the star marked it in the constellation Hercules, consequently the earth does not trace an ellipse in space but a similar, double curve. But we are taught at college that, when the earth's orbit is taken as base line, in estimating the parallax of distant fixed stars, the fixed star seems to revolve in a very small ellipse corresponding to the orbital base line described round the sun by the earth. How is this, when the earth really describes in space a double curve, and how is the extra length of the bsise line through solar translation estimated in calculating the parallax of fixed stars ? W. W. Strickland. [There is no difficulty in principle in distinguishing between the effect upon the apparent place of a star of the earth's motion every year in its orbit round the sun and the motion of the solar system in space. Thus, if we observe the place of a given star on the same date in several successive years, these places would be entirely unaffected by the annual parallax, and the " proper motion " of the star could bo learnt from them. Obser- vations at any other dates could bo corrected for this " proper motion,' leaving the effect of the parallax outstanding. The effects of precession, of the " sun's way '' and of any actual motion in space which an individual star may itself have, arc necessarily cumu- lative, and go on increasing from year to year; the effect of parallax is periodic, and runs through its changes in the course of a year. — E. Walter Maunder.] SUNSPOTS AND TERRESTRIAL TEMPERATURE. TO THF. EDITORS 01<" KNOWLEDGE. Sirs, — -Will you kindly allow me space to assure Mr. Quonsel that he is in error in attributing a connection between sunspots and terrestrial temperature. Your correspondent obviously cannot have road up the neces- sary series of meteorological observations for the past forty years, which refer to a large tract of the earfcli's surface. Mr. Quensel makes no mention of the places where the obsci'vations necessary for his deductions were made. Are we to infer that his remarks arc applicable to the continents of Europe, Asia, Africa, America and Australia? Has he obtained a "mean" temperature from these continents, and then compared it with the sunspofc ciu-ve? Certain it is that up to the present time we have ahxalutehj no evidence that there is the ghost of a connection between the phenomena of sunspots and terrestrial temperature. Louth, Lines. G. McKenzie Knight. [Mr. Maunder has already pointed out thai Mr. Queusel's statement could not be accepted without the figures on which it was based, and we think a similar remark would apply to the assertion made by Mr. Knight. The subject is a difficult one, and it is eviclciit that much more analysis of the observations is rccjuircd before any satisfactory conclusions can be drawn. It must be remembered that the variation of sunspots is only one of the indications of varying solar activity, and that sunspot phenomena alone, therefore, need not necessarily indicate the whole change of solar radia- tion.— Eds.] CLOUDS ON MARS. TO THE EDITORS OF KNOWLEDGE. Sirs, Allow n;c to correct a mistake of mine made accidentally iu my letter published in Knowledge for April. The word " dark " in tho letter should have been " light." In the above letter I tried to call attention to the antagonistic views of Mr. Thomas R. Waring to those of other astronomers as to the visibility of clouds on Mars. As I understand Mr. Waring he states that the atmosphere of Mars is entirely free from clouds, and if so, I should be pleased to know his opinion as to tho natm-e of the " light-coloured, moving spots " to which reference is made by Messrs. Wells and Gregory and other authors who might be quoted. E. Lloyd Jones. TO THE EDITORS OF KNOWLEDGE. Sirs —In your April issue Mr. Lloyd Jones says that in a book by Mr. H. G. Wells and myself, " Honours Physiography " (1893), " it is stated that Mars possesses clouds which are visible in the large telescopes as dark moving patches." I have pointed out to Mr. Jones that no statement a.s to "dark" cloud markings is made in the book, and I should be glad if you would make this disclaimer known. What is said is that Cloud-like 134 KNOWLEDGE. [June, 1001. markings have been seen to obscure for a time the markings on the face of Mars.'' Mention is also made of Prof. W. H. Pickering's conclusion that " Clouds un- doubtedly exist upon the planet, differing, however, in some respects from those upon the earth, chiefly as regards their density and whiteness." So far as I am aware, this is all that is said upon the subject in the book mentioned. R- A. Gregory. Wandsworth, S.W. l^otCccs of Boolts. "The Prixciple.s of MAGXETisii and Electricitv." An Elementary Textbuok. By P. L. Criay, E.sc . (Metliuen.) Sa. 6d.— Several minor inaccuracies and laboured expressions hare been allowed to remain in this book, otherwise we should have no hesitation in speaking of it in terms of untiualified praise. In the preface we read "The nomenclature of the science is largely derived from a period when unwarranted and probably erroneous ideas as to the nature of electricity were held," and this scientific attitude is maintained throughout, save in one or two notable instances. In speaking of magnets and magnetism, p. 1, Mr. W'"^ says : — " It was the discovery in some dim unknown former time," and three lines lower, " discovered at some unknown remote period." In a future edition the first two chapters should be re-written, for the remarks upon lines of force are not clear, •nnd whv should the student naturally assume the law of inverse squares "to govern the strength of field at any point? Anyhow, the assumption is made ; then, to our astonishment, we find on the next page, " We have also seen that it depends on the square of strengths." In Fig. 9 we see iron filings about the centre of the bar magnet. Chapter TV., dealing with the electric field, is good, but we are surprised at finding the coulomb defined as being 3x10' C.G.S. units. The coulomb is, of coui-se, 10~ absolute units of quantity. However, as someone remarked recently, it is absurd that"we should have two units, one three thousand millions times as large as the other. A good description of the plate machine is given, but we note a slight inaccuracy in Fig. 38, the handle being wrongly placed. It would perhaps have been as well had the preliminary notions of potential, as also the water analogy, been introduced before this. The de- scription and theory of the quadrant electrometer forms perhaps the best written portion of the book, but ^ye are sorry to find that the author does not keep clearly before his readers that potential dift'erence is not the same thing as electro-motive force. The remainder of the book is to be conunended. We have, inter alia, chapters on Alternating Currents, The Discharge. Atmospheric Electricity, etc. The index is a very full one. "What is He.\t? and Wh.at is Electricity?" By Frederick Horenden, F.L.S., f.g.s., f.R.m.s. (Ch.ipman & Hall.) Illustrated. 68. — Ihe two conundrums on the title page of this book are but the precursors of a series with which the work is filled. Very little space is devoted to the giving of answers, and, we regret to say, that of the few- answers given not aU are accurate. " The solution," says our author, "of these two fundamental problems is placed in "the hands of the physicists." From this he argues that the whole matter is treated by metaphysicians,, since physicists use mathematics. Next, a heavy frontal attack is made upon the exi.-iting system of mathematics: — "All mathematical operations are functions of objects or actions " : " any number, per se, is meaningless." And later, "What is an object?" "Take a table." We must not, mathematically, according to Mr. Hovenden. speak of one table, because the table is made up of part.s. The parts are of wood, and the wood contains cells made up of atoms. So the only possible unit is the atom. The mathem;itician. we are reminded, has no power to divide the atom, so, he has no right to speak of fractions. Having thus given the quietus to believers in simple arithmetic, it is naturally time that algebraic ide.-is should be abolished. " That part of space which has gained is -t-, and that part which has lost is — . Hence we obtain, as it were, a natural equation : + 1 = — 1." What is to be 'said of such reasoning? There is. however, worse to come, and, as the error led up to is one likely to be troublesome, it may not he out of place if wc take it upon ourselves to answer Mr. Hovenden in detail on this one point. On p. 13, then, objection is raised to the algebraic law which makes the product —100 into —ICO equal to + 10,000— (though, logically, Mr. Hovenden has no right to object, since he has but just enunciated his oira "natural equation"). We read: — "See if we can realise this idea. We will t,ike two bowls, and mark one A, and the other B. In the bowl A are 100 objects. We t.ake the hundred objects out of the bowl A, and put them in bowl B. That is mathematically expressed, bowl A — 100; B -i- 100. Now nmltiply the contents of bowl A ( — 100) by — 100 times, and then, says the mathematician, there aie ten thousand objects in that bowl I " It is upon such reasoning as this that our author stnve-s in his next sentences to be sarcastic at the expense of the mathematician. But here are his mistakes. A contains a hundred marbles he tells us, these are removed to B. Therelore, A now contains 0 marbles (not — 100 as he absurdly suggesis). If he will now perform his operation negatively, 100 times over (that is. take 100 times 100 marbles from B to A), he will certainly find that A contains 10,000 marbles. But, so far, we have only ai rived at p. 14, .and here we propose to pause, for this reason — on p. 7 of his book Jlr. Hovenden has asked "If the foundations are defective, how about the superstructure?" " The Elements of the Differential and Integral Calculus." By J. W. A. Young and C. E. Linebarger. Pp. XVII. and 410. (Hirschfeld Bros. 1900.) 10s. 6d. net.— The attention now being given to the calculus, in technical schools and other institutions where physical science and its applications occupy a prominent place in the curricula, is a noteworthy development of mathematical instruction. Attempt.s are sometimes made to show students who have insuilicieut mathematical know- ledge how to apply the notions of the calculus, but the result must be unsatislactory in the end, and generally leads to con- fusion. No student can obtain a really useful knowledge of the calculus unless he is prepared to devote a fair amount of time to the study of it.s principles. But if he will work steadily at acquiring this knowledge, he wiU find himself eventually in the possession of a most powerful machine, by which innumerable problems can be solved. The functions of the particular case are put into the machine, or the equation to the appropriate curve or surface is taken, and the result can be worked out almost mechanically. As most quantities in nature change or vary according to some continuous law, the differential calculus admit.s of applications of the widest range of subjects. Though this has, of course, long been recognised, yet the calculus has until recent years been taught and studied more from the point of view of pure mathematics than for its practical value. Now. however, several books are available in which the calculus is expounded " for engineers," " for technical students," " for chemists," and other students of science and technology. One of the first books prepared in this spirit was by Profs. Nernst and Schonflies, of Gbttingen, and the present volume is an adaptation of it. The distinguishing characteristic is the continual use of illustrative examples from scientific data, and nothing but praise' can be said for the introduction of this method. The German work was intended primarily for chemists, and a large number of the examples are drawn from physical chemistry. But as a matter of fact, there is very little that is specially chemical in this book, and although this .shows that mathematical chemistiy is still in a rudimentary stage, it also adds to the value of the volume to students who are not chemists. The book opens with a chapter on .-malytical geometry. As students beginning the study of the calculus do not possess usually the power of graphing even the simplest functions, this introduction is essential. After it the chapters deal successively and respectively with limits, fundamental conceptions of the differential calculus, derivatives of the simpler functions, fundamental conceptions of the integral calculus, simple methods of integration, some applications of the integral calculus, definite integrals, higher derivatives and functions of several variables, infinite series, maxima and minima, and differentiation and integration of functions found empirically. While we do not consider that the book contains an ideal course of work upon the calculus, yet it is highly to be praised, and should prove of real value to all serious students of the physical sciences. STANDARD SILVER: ITS HISTORY PROPERTIES AND USES. -II. By Ernest .\. Smith, assoc.r.s.m., f.c.s. Although sterling silver was used in England for the manufacture of plate at a very early period, " the Anglo-Saxons being always reckoned skilful in the use of gold and silver, " the -first statute made for regulating the standard of silver to be used by workers in this metal in England is that of the 28th Edward I., c. 20 (a.d. 1300). It ordains that goldsmiths shall make no worse silver than " silver of the sterling alloy of the coin, or better at the pleasure of him to whom the work Junk, 1001.] KNOWLEDGE. 135 belongeth "" (argent del alloy ds le estcrling ou de . meilleur). aud that none work worse silver than money.* From the table given last month it will be seen that the standard for coinage was altered several times during the int-erval from the 34th of Henry VIII. (a.d. 1512) to the 6th of Edward VI. (.v.d. 1552), but the silver used for plate made during this period appears to have remained " as good as the old standard 925 ; and was not debased like the coin of that period. "t In consequence, however, of the adoption by silver- smiths of the practice of melting the coin of the realm to convert it into plate, legislation for the protection of the coin became nece^sarv in the reign of William the Third. Tile extent to which tliu practice of inanufaclunng plate from the coinage was carried was largely due to the fact that in the reign of James the Second iinniensc quantities of plate had been sacrificed for the use of the King and of Parliament by converting it into money, and that now the opulent gentry were desirous of re- plenishing their side-boards and tables with plate. The melting of the coin of the realm was, therefore, adopted by the silversmiths as the most expeditious way of ob- taining silver " as good as sterling." In order to prevent this wholesale conversion of coin into plate an Act was passed which raised the legal standard for silver plate above the standard of the coinage, thus rendering the latter less available to the silversmith. The Act of Parliament (a.d. 1697-8, William III., c. 8, 5, 9) relating to the new standard states that " it might reasonably be suspected that part of the silver coins of the realm had been, by persons regarding their own private gain more than public good, molten and converted into vessels of silver or other manufactured plat«, which crime had been the more easily perpe- trated by them, in regai-d the goldsmiths or others, workers of plate, by the former laws and statutes of the realm were not obliged to make their plate of finer silver than the sterling or standard ordained for the monies of the realm. ' It was therefore enacted that, from ^larch, 1697, no silver plate should bo made of less fineness than that of 11 ozs. 10 dwts. of fine silver in every pound troy (or 959 parts of silver per thousand), and that no silver vessels, etc., made after that time, should be put to sale until they had been Hall marked. In order to distinguish plate of this new standard it was appointed that it should be marked with the " figure of a woman commonly called Britannia. On account of the softer nature of the new standard, due to the larger percentage of silver present in it, it was found that articles made of this alloy were not so serviceable nor so durable as those made of the old standard. Copper being a harder metal than silver the relative abrasion suffered by alloys of silver and copper is de- pendent on the percentage of copper present. By an Act of Parliament, the 6th of George I., c. 2, s.s. 1 and 41 (a.d. 1719). the old standard of 11 07s. 2 dwts. (925) was revived concurrently with that of 11 ozs. 10 dwts. (959). and these two standards still exist for plate, though only the former is in general use. The standard 925 is alway.i spoken cf as the " old silver standard of England," while the standard 959, • Chaffers, " Hall Marks on Plate," 8th edit , 1 8P6, p r,, f Idem, page 10. although seldom used, is referred to as the " new silver standard," or sometimes as the "Britannia" standard, owing to the fact that silver wai'es of this standard, as stated above, arc marked with the figure of " Britannia." when sent to the Assay Office to be Hall marked. The silver standards used in other countries are also fixed by law. and it is of interest to compare these with the English silver standards. In the subjoined table the staaidards of fineness of silver used for coin and for plate in other countries are given. Table showing the Silver Staachirds for Coin and for Pliite of the I'rineipiil Countries of the World.* (Joins. Pinto. C.uuiry. Fine Silver lierlh.Troy. ozs. dwt. Fine Silver per 1000 parts. 1 Fine Silver per lb. Troy. ozs. (Iwt. Pine Silver per 1000 parts. America 10 16 900 No fixed standard Austria-Hungary .. 10 IC) 9(10 11 8 950 Austria- Hungary ... 10 oi 83.') 10 16 900 Austria-Hungary ... 6 4j 5^0 9 12 800 Austria-Hungary ... 6 0 .500 9 0 750 Austria-Hungary ... 4 16 40) — — Belgium 10 16 900 10 16 9(XJ Belgium 10 Oi m5 9 12 8(j0 Colonies ; — Canada ) Newfoundland ) 11 2 925 — — Ceylon ') Hong Kong '- Straits Settlements ) 9 \2 800 — — Denmark 9 1:2 800 9 ]8i 826 France 10 Hi 9M() 11 8 9,-0 France 10 o; 8;!,'-) 9 12 800 Germany 10 16 900 9 12 800 Holland 11 7 945 U 4 931. Holland — — 10 0 833 India (British) 10 19 916-6 — — Italy 10 16 90J 11 8 950 It;fl"v — — 10 16 910 Italy . — 9 12 800 Japan Japan 10 16 9 12 SOI 80(3 — — Norway aud Sweden 9 12 800 9 181 828-1 Norway and Sweden 7 H COO — — Portugal 10 19 916-6 10 19 9166 Portugal — — 10 0 833 Portugal — — 9 12 800 Russia 10 16 900 10 18i for exjiort 910 Russia 10 8 868 10 Hi 880 Kussia 6 0 500 10 1-5 8-iO Spain 10 16 90J ■ 10 19 916-6 Sj)a!n — 9 0 7.';o Switzerland... 10 16 900 10 10 875 Switzerland .. — — 9 12 800 Turkey 10 Ifi 900 10 16 900 Turkey ... .. • 9 19 830 — — United Kingdom ... 11 2 925 11 2 925 United Kingdom ... — 11 10 959 • CompileJ from Parliamentary Return relating to Gold and Silver Marking in Foreign Countries, February iith, 18'JO, and from other Sources. It will be evident from the above table that the standard 900 is now more widely used than any otli«r, England alone employing 925, that is, 11 ozs. 2 dwts. per ounce troy, thus maintaining the connection with Saxon coins. As previously stated, the silver standard of tnis country has from very early times been computed by divisions of the troy pound. The adoption of the metric system of weights and measures in most other countries no doubt accounts for the use of alloys of decimal proportions in these countries. Alloys of lower KNOWLEDGE. [June, 1901. standard have an advantage over those of higher standard, inasmuch as the abrasion suffered by an alloy with 90 per cent, of silver would be less than that suffered by an alloy containing 92.5 per cent. As silver and copper are capable of uniting in all pro- portions by direct fusion, standard silver is prepared by melting together the requisite quantities of the two metals. The fusion is usually effected in plumbago crucibles, those in use at the Royal Mint having a capacity of 4000 ounces. Alloys of these metals possess the characteristic piu'e metallic whiteness of silver until the copper amounts to 50 per cent, of the alloy, and the tint becomes more and more red with the increase in the amount of copper above this limit. The effect of copper is to increase the hardness and elasticity of the alloy, hence silver is always alloyed with copper to obtain the hardness required to enable it to withstand the wear to which coins, etc., are subjected ; pure silver, as previously stated, being too soft for the purpose. The hardest alloy of these metals consists of about 31J^ per cent, of silver and 68f per cent, of copper, or a ratio of 5 to 11. Although the products of the fusion of silver-copper alloys in any proportions are comparatively homo- geneous, yet it has long been remarked that ingots of alloys of these metals are not absolutely identical in composition throughout. Considering that silver-copper alloys of various com- position have long been used universally for the pur- poses of coinage and plate, it is not surprising that this series of alloys has been the subject of careful experi- ment, and much is now known respecting them. Recent research has shown that one of the most interesting facts connected with them is the remarkable molecular re- arrangement they undergo during solidification. Levol, who is one of the chief authorities on the subject, concluded that the only homogeneous alloy of the series contains 71.89 per cent, of silver and 28.11 per cent, of copjier ; and he considers this alloy to be a definite compound of the two m.otals having the formula AgjCu.j. All other alloys of silver and copper Levol regarded as mixtures of this definite alloy with excess of either of the metals. His experiments showed that in alloys containing more than 71.89 per cent, of silver the centre of the solidified mass is richer in silver than the exterior, while in alloys of lower fineness than this the centre contains less silver than the external portions. J Sir Roberts-Austen repeated many of Level's experi- ments, and concluded§ that uniformity in composition of the series of silver-copper alloys depends greatly on the method of cooling. By slow cooling many alloys other than the one mentioned above may be made as uniform as it, its peculiarity consisting in the fact that its composition is iiniform whether it is cooled slowly or rapidly. With regard to the homogeneity of English standaed silver (925) cast under ordinary conditions, it appears from a long series of experiments made some years ago by Col. Smith for the Indian Mints|| that the tendency of the silver and copper to separate depends upon the inequality of the rate of cooling in the different parts of the ingot. The act of cooling causes a partial + Ann. de Chim. et de P/;».t., Vol. 30 (18.52), p. IQ.^i ; Vol. 39 (1853), p. 1(53. § Pror. Soil. Soc , Vol. XXIII. (1875), p. 481. 11 Idem, p. 433. separation or liquation of the copper towards the sur- faces which cool first, those parts of the bar being richest in silver which solidify the last. The researches of Roberts-Austen have shown that the maximum difference in the composition of an alloy containing 925 parts of silver and 75 parts of copper is only 1.40 parts per thousand when the alloy is slowly cooled, while it is as much as 13 parts per thousand when the alloy is rapidly cooled. The irregularity in the composition of standard silver due to liquation is a matter of great importance in mints where the production of alloys of uniform composition, is very desirable. With suitable moulds and uniformity of cooling liquation may be almost entirely prevented, but unless great care is exercised in the preparation and casting of the alloy the irregularities in the composition will be much greater than those quoted above. In establishments whei-e standard silver is prepai-ed for trade purposes and is subsequently manufactured into goods to be Hall marked it is the common practice when prepaxing the alloy to add a little extra pure silver beyond the quantity actually required. This is done in order to overcome the irregularities in composition due to liquation, and to obtain an alloy which will be a little above the standard in all parts and thus satis- factorily pass the Hall. Standard silver, apart from its attractive appearance, possesses many properties which render it valuable in industrial art. It is very malleable and ductile, and can be readily rolled into thin sheets and drawn into very fine wire. It possesses a brilliant metallic lustre and is capable of taking a high polish. One of its most valuable properties is the readiness with which it may be made to " flow " tinder pressure. It is well known that " when a malleable metal or alloy is ex- tended by mechanical processes, such as rolling, stamp- ing, or hammering, a true flow of the particles of the metal occiu's, analogous in all resjjects to the flow of viscous fluids. The i^ressure exerted upon the surface of the metal is transmitted in the interior of the mass from pai-ticle to particle, and tends to produce a flow in the direction where the resistance is least."1I The application of this fact, that solid metals and alloys flow like viscous fluids, is of great importance in industrial art, and the production of various complicated and artistic forms with standard silver by stamping, sjjinning, chasing, etc., entirely depends on the flow ,pf the metal when suitably guided by the artificer. The striking of coins presents a familiar instance of this valuable property of standard silver, the metal, under pressure, being made to flow into the sunken portions of the die without fracturing, thus producing a true impression with every detail clearly defined. The stamping of knife handles and small trays also affords a familiar example of this property. The art of stamping and shaping ai'ticles of jewellery, etc., in a press from sheets of standard silver came into general use just previous to the first Exhibition of 1851, and a very large quantity of work is now produced by this means. During the mechanical processes, such as hammering and stamjiing, the metal becomes more or less haixl and brittle, and requires to be annealed at frequent intervals. This is effected by heating the metal to a dull red heat in a non-oxidising atmosphere, whereby its original softness is restored. IT Percy. "Metallurgy," Vol. I., page 22. JlNE, 1901. ^ KNOWLEDGE. 137 By the application of certain processes the surface of standard silver may be made to assume various tints. by which means the ai'tistic effect is increased. When silver-copper alloys are heated to dull redness, with access of air, the surface becomes blackened, owing to the formation of a film of copper oxide, but by blanching — that is, immersion in hot dilute sulphuric acid — the copper oxide is dissolved, and the silver assumes a beautiful dead-white appearance known as ■' frosted silver. When silver articles have been thus frosted and the portions in relief are burnished, very effective results are often obtained, and the beauty of the ware greatly enhanced. Articles of plate maj' be '' frosted,' oi-, as it is some- times termed. " matted or deadened," also by boiling them in bisulphate of potash, which acts in the same way as dilute sulphui'ic acid. In order to obtain on ornamental silver wares the effect known as oxidized silver, the surface is darkened by a thin film of silver sulphide, produced by boiling the articles in an aqueous solution of potassium sulphide, and then i-ubbing with very fine pumice, which re- moves the dark layer of silver sulphide from the portions in high relief and leaves dark lines in the more deeply- cut recesses. The effect thus produced is frequently very sti'iking, and adds materially to the appearance of the article. At the Paris and London Mints** silver medals have recently been subjected to the process known as " sand blasting," by the aid of an appliance which projects against the surface of the medal a small jet of air carry- ing with it fine sand, and having a velocity of about 180 feet per second. When thus treated, the surface of the medal becomes " frosted," and may be subse- quently oxidized as above described, or the following process may be adopted. The " frosted " medal is immei'sed in an alcoholic solution of platinum chloride, whereby the surface becomes blackened by the deposition of a thin film of metallic platinum. Subsequent rubbing with a brush and very fine pumice changes the blackened surface to a delicate gi^ey, and if this operation is con- ducted skilfully, graduated shadows may be left where- ever the artist considers their presence to be desirable. The beauty of the medals so treated, and the fidelity with which the details of the design are revealed, is beyond question, but it may be doubted whether the surface of the medal is permanently protected. {To be concliithfl.) TO THE WHITE NILE-FROM KHARTOUM KAWA. AN ORNITHOLOGIST'S EXPERIENCES IN THE SOUDAN. By Harry F. Witiierby, f.z.s., m.b.o.u. II.— THE RIVER— E.SSEXTIAL ALIKE TO MAN, BEAST AND BIRD. Having obtained all the necessary permits as well as bag- gage and riding animals, oiir next task wa.s to engage ser\'ants. We eventually gathered together a motley and somewhat amusing crowd. The chief of these — one Hassan Mahomet Eshari, an Egyptian — we brought from Cairo, and he proved in every way an excellent interpreter and hard-working headman and servant. Mustapha, who hailed" from Berber, was a cook as well »• 28th Report of Riyal Mint, 1897, \k J7. as a lazy and perfidious rascal. Mahomet— an old kingly-looking Turk, whose ankles were callous through the shackles of the Khalifa — was " sais " to the donkeys, lie was a fine figure, and generally rode in front of our caravan, ordering the natives out of the path, or com- manding them to come and show the way for a mile or two, all in a most dignified manner. But when it came to work in camp his one idea was to sit on his haunches and smoke, and to obtain the services of the nearest wandering boy to wait upon him and his donkeys. The natives feared him much, and generally obeyed him without a murnuir, but all our hard sayings and harder doings failed to make much permanent improvement in his habits. Wc had great expectations of Mirsal, an old Soudanese soldier, who was to act as a gun-bearer. When 1 engaged him he went through a most charming panto- mime. Gripping his right arm with his left hand, he swore by the Prophet's beai'd that so long as there was strength in that arm ho was my most faithful servant. A few days later, when on the march, we sent him over to a village on the other side of the river with money to buy food and tobacco. We never saw him again, nor could policemen mounted on camels find him. But maybe wc misjudged him. The strength may have for- saken his arm. Our camel men were from Dongola. They were a lively, irresponsible crew, requiring much physical persuasion. On the whole, we were not greatly impressed by the reliability of the natives of the Soudan, as far as concerns either work or honesty. Our final plan was to travel up the river quickly, and to return slowly. While marching up the river we, of course, should have no time for collecting or Muliomet at Work. Ft-oin (I pholo'ji-*tiih l_i>i Mr. »_', F. CambukN. preserving, but we should be able to make notes of the birds and the country, and thus obtain a knowledge of the ground which woxdd greatly assist us on our return in deciding where to make collecting camps, and how long to stay at each. With much kind help from many in authority at Omdurman all our preparations were at last complete, and on the afternoon of March 20th, we sent our men, animals, and baggage across the White Nile to the Khartoum, or east, bank. Joining them early the next morning wc found to our gieat relief that there were no deserters, and, moreover, that all disputes as to which box or package should be carried on which camel were settled, and all were ready to start. The apportion- ment of loads and the loading up at the start arc always difficulties, and never before had we experienced so little trouble. 138 KNOWLEDGE. [Jl-NE, 1901. It is remarkable how regular a stride and how even a pace the baggage camel will keep up hour after hour. Two aud a half miles an hour is his pace, and twenty miles is for him a good day's journey. As the camels carried our food, tents, beds, and indeed all our baggage, we had to arrange our day's march according to theirs, our procedure being generally as follows: — Rising just before the sun (about 5 o'clock) we breakfasted, struck tents, packed up and got away about seven, marched for five hours, then rested during the heat of the day. and mai-clied again for some two or three hours in the after- noon, getting into camp as the sun was going down, about 6.30. We travelled thus to a point some ten miles south of a town named Kawa, on the east bank of the White Nile, about l.jO miles south of Khartoum, and there we stopped and made our first collecting camp. A reference to the accompanying sketch map will give an idea of our route. We marched as a rule close along the river, which was in many ways more convenient and pleasant than the desert track. At high Nile the route by the river is impossible, as much of the laud is then flooded, and long detours here aud there are neces- sary to avoid the " Khors " (equivalent to the Scuth African " dongas ' ). some of which during the rains are often impassable torrents, whereas in the hot season they are merely dry watercourses. Often we rode for miles along the narrow strip of short grass which iu places grows by the river, but now and again this pleasant going gave way to soft sand which was trying for the donkeys, and, if a heavy wind was blowing, dis- agreeable for us. But more annoying still, and more frequent, were the wide stretches of mud covered by the river during its flood, but now hard, caked and Clacked in every direction by the powerful sun. So large and deep were these cracks, and so numeroiis, that our donkeys continually got their legs into them, the result often being a sudden collapse of the beast and the discomfiture of the rider, while sometimes a donkey's legs became so firmly fixed in a crack that it required our united efforts to lift him out again. After due experience of this method of travelling we avoided the wider stretches of mud by turning off into the desert track, which although hot and dusty, was at all events firm. One does not need to travel far up the White Nile ill the dry season to be impressed by the glaring fact that the life of every man, beast and bird in the country is entirely dependent upon the river. Beasts such as camels and even goats can be gradually trained to exist without water for as long as two or three days, but man cannot live long in this burning country without the life- giving water, as many a poor wretch has proved, while birds are even niore dependent upon it. There is no dew, and save for a small well here and there at kng intervals, water can only be had at the river. Man. or rather woman for him. has to come there to get his water, and thither he has to drive his camels, cattle and goats, often from long distances, to drink. To the river every morning and evening, as regular as clockwork, flock after flock of sand- grouse and pigeons come down to drink. All day long small birds are passing to and fiom the trees and bushes to the river's edge, while at dawn or in the evening, wild beasts of many kinds come from their haunts on the same errand. But man is dependent upon the river not only for the water he drinks, but largely also for his food. It is true tiuit much " dhura," the corn of the country, is grown during the rainy season out of reach of the Nile even at its greatest height, but by far the larger part and the richer part of the culti- \atable land is the mud which so troubled oni' donkeys, and this mud is entirely dependent u|)on the flooding of the river to render it fit for agriculture. The same may be said of the islands in the river, which are covei'ed at high Nile, aud after- wards prove of the utmost value for culti-' vatiou. So rich is the land on these islands that even the lazy Soudanese find it worl h their while further to utilize the river liy raising the water with the " shadoof," and so continue cultivation during the dry season. At the time of our journey these islands were almost the only green spots iu a wilder- ness of brown and sun- scorched land. At long intervals only, did one or two "shadoofs" keep green some small patches of onions, water melons or beans on the mainland. As a highway, the river is extremely valu- able. Sailing boats of vai'iouskinds — gyassas, feluccas, nuggars aud even dahabiehs — are continually travelling up and down laden with corn and other produce, while rafts of all sizes are numerous Skftcli Mail, sliowing route and cullecting camps. The timber forming a raft is generally of the *^sont" tree, a species of acacia, aud is cut by a few natives who join together for the pur- pose. When tlic wood is cut and floated, and the raft completed, they thrust it out into the river, and are then entirely at the mercy of the current, which flows some one or two miles an hour in the dry season. These men make their home on the raft, protecting themselves from the sun by iinjirovising awnings of the cloths which they wrap round their bodies at night. Eventually the current carries them to Omdurman, where they get a~ good price for the wood as fuel, which is exceedingly scarce near the town. Besides the sailing boats and rafts, steamers ply up and down the White Nile at least three times a month, to carry passengers, and to take rations and other things to the troops stationed at various points. Now that a channel has been cut through the Sudd on the upper White Nile the river is navigable for 1000 miles south of Kliai'touni. Prom Cairo to Khartoum is some 1500 miles by river. Some day when channels have been cut flirougli the cataracts, by no means a very icniote pro- Jr.NE, 1901.] KNOWLEDGE. 139 bability. it will be possible to steam l!500 inilos up this wonderful river at all times of the year. The wild life in the river and along its banks was a eoutinual souree of pleasure to us as we rode along. Hippopotami were rarely seen, but now and again an enormous black licad would show above the water for Boatbutldiug on tlie Whit* Nile. Fioiu o Pliotoci.-niili !.]( Mr. C. K. C.\miuih \nj Mr. L'. F. Camiuiun. in sight wading in shallow water or stalking about on the short grass by the river. We sometimes passed within a few yards of a group of crowned (!ranes,§ with their rich colouring of black, white, and chestnut, and their curious tufts of golden grass-like feathers, and at one camp a confiding old bird used regularly to roost on the top of a tree near our tents until ho was added to our collection. The sacred ibis.jj celebrated by having been much mummified, and by its many portraits upon the tombs and temples of ancient Egypt, was most confiding. This bird only visits Egypt during the period of inundation, and consequently very few tra- vellers in that country see it, the buff-backed heron being made to do duty for it by the tourists' dragoman. However, the real thing is totally unlike the substitute. Its jet black head and neck, which arc bare of any feathers, and its black legs, serve to accentuate the pure white plumage of its body, while its wings arc edged with black like a mourning envelope, and from each shoulder droop green-black feathery plumes. When flying towards one the bird seems to be streaked with blood, for the wing-bones aa-e bare of feathers on the under side, and the skin which covers them is of a rich vermilion colour. At intervals along the river were beds of shell fish (Aetheria) like oysters. The Nile fell so low m 1900 thai a great many of thest' " oysters " were left high and dry. and were consequently decomposing. Yet numbers of" wading birds frequented the beds, and *» For a full arcouiil. ot llie bird- .■idlefled aud ubBer\ed during the expedition see the Ibis, April, UWl, pp. 237-278. t Chenalopex agnptiacus, Hriss. X Plectropterus riippelU, Sclat. § Balearica paoonina, Linn. \\ Ihis icthiopica. Lath. 140 KNOWLEDGE. [June, 1901. amongst them none were more conspicuous than the Marabou storks, H the African representative of the adjutant of India. Not only were they conspicuous by their size and form, but their dull-looking plumage, their bare rcddish-ycllow heads, and their enormous dirty bills, gave them a most revolting appearance. Tliey are carrion feeders, and seeing them smash open the oyster shells with their massive and powerful bills one could well understand how it was that after the battle of Om Debreikat many a man, well accustomed to grue- some spectacles, shuddered at the sight of corpses mutilated by these birds. Another interesting member of the stork family which frequented the " oyster " beds was a sombre coloured bird with a thick whitish bill, the mandibles of which are so grooved near their tips, that an open slit is left when the bill is closed, a peculiarity which has given the biixl the name of open- bill.** Of the many other birds frequenting the river the pelicansft were, perhaps, the most striking. One evening as we urged our mounts over the brow of a small sandhill we came suddenly in sight of a great flock of these birds in the shallow water at the river's edge. Some were dozing, others were preening their rose-white plumage, others were dabbling their clumsy-looking bills in the water and washing their yellow pouches, while over the whole flock the setting sun threw a delicate rosy hue. For so large and heavy a bird the flight of the pelican struck me as being peculiai'ly graceful. A few powerful flaps are given as the bird rises slowly o3 the water, then the wings are outstretched and it skims straight and swiftly along within a foot of the surface for some hundred yards, then curving slightly upwards, it flaps its wings again and is prepared for another long floating flight. Before leaving the river and its attractive bii'ds, the black-headed plover, |I or courser, a bird somewhat smaller than the golden plover, deserves mention if only on account of the interesting and historical habits accredited to it. There can be little doubt that this bird IS ihe "Tpoy^iXo;" of Htrodoius, who ascribed to it the hahit of attpndinR erncoddes. and of feeding in their open mouths. At least two naturalists in modern times have actually observed the bird thus act. Some ornithologists, however, are disinclined to believe that it does really enter the crocodile's mouth, and suggest that when a crocodile is lying with its mouth wide open, a bird running about on the sand behind the mouth would appear at a little distance to be actually between the reptile's jaws. However this may be it seems a pity now to discredit a habit which has made the " crocodile bird " a celebrity for so long a time. I am sorry to be unable to give any evidence on the sub- ject. The bird was very common along the banks of the White Nile, and we much admired its rapid and graceful actions and its beautiful plumage of delicate blue-grey marked with white and black, but we never saw it near enough to a crocodile even to suspect it of engaging in the laborious and risky task of picking the reptile's numerous and merciless teeth. *S Leptoptilus crumeniferus, t'uv. »* Anastomus lamelligerus, Tcniiii. tt Telecanux onocrofalus, Linn. Xt Pluviamis agiipHux, Linn. Kote. — Tt iilionkl have been stater! in my i!r«l article (Knowledge, April. 1901) that tlie pbcit.ogra]ihs from -nhich it was ilhistrated were taken by Mr. C. F. C'ambiirn, one of tlie taxidermists who accompanied me on the expedition. Bvittst) (!^rn(tt)oloa(fal Notes. Conducted hy Harry F. 'WiTnERBY, r.z.8., m.b.o.u. Early Appearance of the Nightjar in Hamp- shire.— On May 5tli I put up a Nightjar near Burley, in the New Forest. As is well known, the bird rarely arrives in Eugland before the middle of May, and the oth of the month is undoubtedly an unusually early date for its ap])earance. Judging fnmi the experience of several correspondents as well as from my own, the bulk of the migrants have arrived this spring- at their usual dates. The late spring in this country could of course have no influence on birds coming from a distance, but the season has been cold and liackward, seemingly, in the south of Europe, and it is surprising what little influence this has upon the regularity of the return of our summer migrants. — Harry F. Witherby. Mimicry by the Butcherbird, — It has been said that the Great Clrey Shrike imitates other birds for tlie purpose of attracting them within range of attack (Yarrell, British Birds; Ed. ""4, Vol. I., p. •2ul). Yarrell noticed that the Red-backed Shrike or Butcherbird has a note like that of the Housesixxrrow. In " The Evolution of Birdsong," I suggested that this note might be the loud " chell " or " tell " of alarm given by the Butcherbird, and which is somewhat similar to a note of the Sparrow. On the 5th of May, liowever, 1 obtained evidence support- ing the idea of voluntary mimicry on the part of this bird. In company with Mr. A E. W. Paine, of Swords House, Leddington, Ledbury (a life-long observer of birds), I was cycling across some open land, and saw within ten yards of the road a Butcherbird on a post, evidently singing. The bird seemed to fear no harm from cyclists, and con- tinued its song while we passed. We both heard it give in its warble very distinctly the "' twink " or " pink " of the (!haffiuch. A thick hedge commenced at the spot, and in the shelter of it we dismounted and listeued to the curious babbling song of the bird, and heard it utter some notes closely like those given by a Sparrow when singing. One feature of the song (and I heard the same in a captive Butcherbird) was the alternation of soft and loud passages in one strain. A minute later a noisy cart rapidly passing scared the bii'd to a distance, where he began to feed. I watched him for some time through a telescope. No other birds were near, except a few Sand Martins. — Charles A. VVitchell, Charlton Kings, Cheltenham. Arrival of Swallows. — I can report the sight of my first Swallows this year, on April Sth. The dates for seven years past on which I have first seen Swallows here are as follow :— 1895, April loth; 1896, April 12th; 1897. April 7th ; 1898, March 14th ; 1899, March 29th ; 1900, April 15th; and 1901, April Sth. I saw the first Swifts this year on April 19th. — E. Sillence, Romsey. Ornithological Notes from Norfolk for 1900. By J. H. Gurnev, F.z.s. (Zoologist, April, 1901, pp. 121-140). For many years llr. Guruey has contributed to the pages of (jnr contemporary a useful and interestmg record of the ornithological events occurring during the year in Norfolk. As far as rarities were conc-rned, 190J was luieventfiil. At the beginning of January a good many Bitterns were reported. During Feliruary and March a very large number of Little Auks were washed up on the East Coast. In 1895, it will be remembered, there was a similar incursion all along our eastern seaboard, but in 1900 the birds seem to have kept more together, and most of them perished in Norfolk. Previously recorded irruptions of the Little Auk in Norfolk have occurred in October, 1841 ; December, 1848; November, 18H1. It is satisfactory to learn that Spoonbills continue regularly to visit Norfolk in slightly increasing numbers. With Mr. Gurucy's observation that the Tawny Owl does not leave castings in its nesting hole we cannot agree, having repeatedly found the reverse the case. JlTNK, 1901.] KNOWLEDGE. 141 Conducted by >r. I Cross Fine Ap.iustmknts — In the details of th>^ construction of microscopes, as in fact in every other instrument or machine, there is no re-al finality, and each year sees the introduction of some slight improvement which may tend to make work easier and more accurate. A study of the catalogues of the various microscope manufacturers of a year or two ago wiil afford food for reflection, for nearly every noted maker then expressed hi.s unbounded confidence in his particular form of fine adjustment. One states that his " must be considei-ed to be a triumph of mechanic;!! skill," another " has proved absolutely satisfactory," and a third " its reliability is unsurpassed." Yet within the space of a few months nearlj- all the leading makers found it ilesirable to introduce new devices for fine adjustments. All of them have distinctive features, indicating that care and con- sideration have been given to their design, and it will probably prove of interest to readers to be made acqu.ainted with such particulars as I have been able to collect from the various makers, for every new idea which enables the worker to manipu- late more preciselj" than available means have permitted him formerly to do, should receive both consideration and recom- mendation. A perusal of the paper read before the Royal Microscopical .Society, by Mr. E. M. Iselson, and reported in the Society's Journal for August, 1899, on the "Evolution of the Fine Adjustment," conveys some idea of the gradual improvement that has taken place in tliat movement. Those who use a substage condenser giving a small aplanatic cone will probably not feel the necessity of a better fine adjust- ment than that which is usually fitted to student's stands havin" the direct pillar action. Directly an illuminating cone bearing a fair proportion to the nnmericiil aperture of the objective is used, the necessity for a slow and precise movement by fine adjustment becomes over- whelmingly apparent. In a previous article T referred to the fact that many new substage condensers yielding large cones of illumination had been recently introduced, and as the supply of such articles must indicate a demand, it necessarily follows that people who have used them have discovered the weakness in the fine adjust- ments of their instruments, have called for something better, and response is being made by manufacturers to meet this fresh demand. There are four new fine adjustments which I propose to review, as follows : — The Continental pillar fine adjustment with levers, designed by Reichert, of Vienna ; the new fine adjustment fitted to their photo-micrographic stand, by Zeiss ; the " Ariston," by Swift and Sons ; and Stringer's fine adjust- ment, by W. "Watson and Sons. Reichert's Fine AiucsTMENT.— The great weakness of the Continental pillar form of fine adjustment ha'' been consequent principally on the difficulty of producing a sufficiently slow rate of movement with a direct-acting screw that would stand wear and tear. The problem has been met by Reicliert's device, which consists of a screw, having a point which engages two lever arms, the upper pressing upon the lower, and being mounted from the outer .sides of the pillar. To the under sides of these levers is attached a piece of hemispherical shajied meta:, which has on its curved side a point which communicates the motion. A reference to the illustration in our next number will make this otherwise obscure description quite clear, and it will be further seen that the rate of movement is dimini.sbed by the proportions of the lever arms, which are .about i\ : 1. This would mean that if a screw of the ordinary kind were used, the rate would be reduced to ^J,^ in. for each revolution instead of .jJj^j in. as in the old pattern. (The illustmiiou referred to in the alcove note will appear iu the July number of Knowledqk.J The Mrcnoscoi'F, ..\nt) the Phaumaceutical Che mist, — To the bus}' medical practitioner, reference to the microscope for diagnostic purposes is a matter of every-daj' occurrence. Those who have not the time or disposition to do the work them- selves, have at their disposal associations and laboratories which cater for their special needs. In addition to these facilities, it is becoming usual for pharmaceutical chemists to make them- selves acquainted with the wants of medical men in these respects, and to be prepared to make the examinations, and to provide themselves with the necessary modern apparatus for so doing. The microscope; is becoming increasingly important in the curriculum of the pharmaceutical student, and it is in no small degree due to this profession that so much of our food and drugs that once were adulterated, arc now purer and of better quality. Powdered drugs and spices were frequently mi.Ked with starches, flour, etc., but the microscope ((uickly discloses such foreign materials. The knowledge of active constituents and other cell contents of medicinal plants, and their distribution in different tissues and organs is becoming increasingly com- prehensive and accurate, and experiments aided by the use of special micro-chemical reagents are in progress to identify the vegetable alkaloids and related substances raicroscopicilly. It is a satisfaction to know that work of so thorough a nature is in progress, and it is a guarantee that with increased and more general expert knowledge, our food, drugs, and other commodities will be purer and finer than they have been. The WiiKKSHoi's of E. Leitz, Wetzlar. — A correspondent sends a description of his visit to the microscope factory of this noted optician. The following is a short ivsumi; : — 50UI) microscopes per annum is the output of this house, leading one almost breathlessly to ask " "What becomes of them all '? " Leitz's gre.at feature is that he confines himself entirely to microscopes and their accessories, instead of producing scientific instruments of every description as English opticians generally do. Herein lies the secret of his success. With a large and regular demand for certain fixed models, a system of production in which machinery plays an important part is possible, and ensures sound construction with a minimum of cost. The supervising and testing departments are of the most thorough description, and when the care that is taken is known, it is not to be wondered at that the Leitz objectives are credited with being more uniform in quality than any others. It has many times been stated that the reason why Con- tinental houses produce cheaply is because they employ women workers. Leitz has no female labour at all ; all his men are skilled mechanics, the majority of whom have been trained in the works. It is quite possible for English houses to compete successfully with foreign competitors if they do but adopt their methods, which may be summarised in a few words. Have the works in a country town where rents are low, and the cost of living less than in London. Have suitable buildings for workshops, and the rest is a matter of system and machinery. NOTES AND QUERIES. //. Deo-ey. — The two books that are likely to give you the information you require are "A Populir Hand-book to the Microscope," by Lewis Wright, price 'Js. 6d., and " Modern Microscopy," by Cross and Cole, price 3s. 6d. More costly works are "The Microscope," by Hogg, new- edition, price 10s. 6d., and '" The Microscope and its revelations," by Carpenter, edited by Dr. D.illinger, a now edition of which is promised for next July. Chalk wit»Siii;lls. — In a previous nutnber I ofE.>red to send a correspondent a supply of Foramintferous Limestone. Several readers have asked that I would also give them some. I shall have much pleasure in complying with their requests if 142 KNOWLEDGE. [June, 1901. they will kindly accompany their application with stamps to cover cost of postage on the material. Red Rain.— In connection with the recent falls of so-called red rain, I have received letters from two correspondents, one of whom enclosed a small quantity of material distributed by Captain C. J. Gray, which had been collected by him after a heavy fall of rain on December ^Sth, 1896, in Melbourne, Australia. I have had the material mounted, but the quantity which I received did not contain the variety of matter that some other correspondents have noted. Observed by transmitted light, there were few characteristic particles, but with the aid of a°polariscope I was able to detect some small crystalline fragments of the nature of quartz, etc. It seems more than pro°bable that the phenomenon arose in consequence of one of those heavy winds which have been known to carry dust from the Sahara as great a distance as 500 miles, and which in this case may have passed over some sandy tract in a like manner. The material has all the api)earance of such dust. There are some interesting references to falls of red rain in P. H. Gosse's " Romance of Xatural History," but none of them are of the .same nature as the dust at present under consideration. Dr. n. M. Whclphij.—l have to give you my best thanks for so kindly sending the numerous interesting papers in connection with chemical and pharmaceutical subjects, and especially for the engraving of the Pre-Columbian Indian Flint Implement. This is certainly a most interesting and peifect specimen. Comnuui lea 'ions and enquiries on Microscopical matters are cordiaUy invited, and should be addressed to M. I. Cross, KNOwr.EDGE Office, 326, IIi(/h Holborn, W.C. NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. T.ARGE Comets.— Pnif. A. Kn-ulz, nlilnr ol' (lie Axtronomisi-Iii- NachricMen, has recently issued a work giving the results of his eumimtiitions and eouipansous of (lie orl)it3 of the comets of 1680, 184H I., 1880 I., 18S2 11.. 1887 I., ete. These several objects offered some s'uggestive resembhuices hotli as regards their physical features and their orbital elements. But they appear to have l)eeu, iudividuidly, rtistinet bodies revolving in ellipses of long period. They exhibited, liowever, a sufficient all-rouud similarity to warrant the inference that thev originated from the same source, and may ha\ e )irimarily formed an immense eomet, which meountered d^turbances of sueh force as to diseoiuiect its uiatei-ial>. and distribute f lu-ui into a family of large comets of various periods, and with perilielia remarkably elose to the 8UD. Tlie time of revolution of the eomet of 1680 was about 8449 years, of 1843 I. 511 years, of 1880 I. and 1882 II. 800 years; but in llic ease of 1887 I. the elements are extremely uncertain, the eomet being only observed on a few nights iu the Southern Hemisphere. Certain o'tlier bright comets, iu aclrlition to those speeified, exhibited features of orbit and aspect whiih indieate their ])ossible identity with the class alluded to, but the observations were not very accurate, and reliable conclusions cannot be deduced from them. Xew Comet. — On April 2:irtl, a telegraphic dispatch from Sydney reported that a brilliant comet was seen in Australia, and the same objeet was observed at Capetown during the two hours preceding suiirise. It had a triple tail ten degrees in length. The astronomers at Yerkes's Observatory are said to have picked up tlie eomet on the morning of April 27tli, uud it was seen by several observers at Eastbourne, according to the newspapers, on "May 1st, at 3 a.m., but as the comet did not rise in England until after 6 a.m. on that mornini; the observers must have been deluded by some false appearance. Tlie perihelion passage occurred on .April 54th. at a distance of about 23 millions of miles from the -un. The following extracts from an epheraeris by Kreutz, Ast. Nach., 3712, will show that during Ma_\ the comet rapidly receded from the earth, and became so faint as to be practically invisible in the strong twilight of the season :— Distance from Date. R.A. Dee. Bi-ightness. Earth in Mil. H. M. s. * ' lions of Miles. Mav 4 ... 3 57 49-0 144 . . 037 ... 82 "14 . . 5 31 49 + 3 2.5-9 ... 0 ()9 ,.. 107 " 24 ... 6 20 18-1-6 21-2 ... 0(« ... 138 On June 1st, the comet will be about one-lnmdredtb part as bright as it was when near perihelion, and will be situated in about 100'' + 8°, so that this object which afforded such a conspicuous aspect in the southern hemisphere, has virtually come and gone (like the tine comets of 1880, February, and 1887, January) under conditions which prevented a single glimpse being obtained by northern observers. The Aphil Meteors. — The weather generally was very favour- able for the observation of these objects, and moonlight offered no interference until the later stages of the display. Usually meteors are very scarce in ,\pril, and this year proved no exception to I he rule. At Bristol the writer obtained observations on April 13th, 17th, 18th, 19th. 20th, 2Ist. 23rd and 2ttli, and during watches amounting in the aggregate lo 19 hours saw 122 meteors. The first byrid was I'ccorded on April 18th, at 13h, 19m., and it was fortunately also mapped by Prof. A. S. -Hcrschel at Slough. It descended :it a normal elevation above the earth's surface, and its radiant at 266° + 33° proves that this centre, like that of the Perseids, moves eastwards during the time of its visibility. On April 20th, during a watch of five hours the writer noticed 29 meteors, but there was not a single Lyrid amongst them ! Yet, on April 21st, during a watch of 3^ hours 25 Lyrids were seen, and 27 other meteors. It was evident that on this night the shower reached a definite maximum. Allowing for time spent in registering the paths, etc,, the horary number of Lyrids for one observer was about eleven. The radiant point on April 21st was at 270' + 33", showing an ea.sferly drift of i degrees of R.A. (equal 3 degrees of space) during the three nights. The following ephemeris will probably re|n'e.~cnt the |)lare of the radiant pretty aecurafclj- on eleven nights, and it will be importaut to test it by future <»bserv;ition8, but the shower is exeeedingly feeble at its earlier and later stages, so it will be advisable to incorporate the paths i>f different observers : — a S ' a 5 Date. o o Date. o o April 15 ... 263^ + 33 Aprd 21 ... 271 -t- .33 16 ... 264J + .33 „ 22 ... 272^ + 33 „ 17 ... 266 + 33 „ 23 ... 273i + 33 „ 18 ... 267i + 33 „ 24 ... 2745 -H 33 19 ... 2G8i -h 33 ,, 25 ... 276 + 33 „ 20 ... 2692 -f 33 1900 not being a leap year the effect will be tlmt for some lime iu tlie future th<' maximum will occur one day later than formerly. Thus the tjuadrautids will occur on January 3rd instead of January 2nd, the L\ rids on April 21st instead of April 20th, and the Perseids on .\ugust 11th instead of August 10th. The recent display of Lji'ids was successfully observed by several observers iu various parts of Knglaud. Prof. Herschel at slough made a considei'alde number of accurate observations, and remarked the singular scarcity of nuHeoi's except on the special night, April 21st. He then saw 18 Lyrids in about three hours, nearly all 1st or 2nd magnitudes. Mr. C. L. Brook, of Meltham, near Huddersfield, counted between 40 or 50 meteors on April 21, including a number of Lyrids. One of tlie most brilliant of these appeared at loh. 8m.. and was also recorded by Mr. T. H. Astbury, at Wallingfoi'd, and the writer at Bristol. It fell from a height of 70 to 51 miles over the Midlands. But the most interesting meteor observed at more than one station during the recent display was that of a bright Cassiopeid which came into view at llh. 2im. on April 21. Its radiant, from observations at Meltham and Bristol, was at 21 -t- 59 ' near J Cassiopeia;, and it descended fi'om 66 to 44 miles in a path of ."io miles, directed from north to south over the counties of Carnarvon, MeriiMietli, and Cardigan, in Wales. Its velocity was 14 miles per second. It is remarkable that slow-moving fireballs often take their flights from this radiant near J Cassiopeia" in the spring monlhs of Ajiril and May, though ordinary shooting stars come rarely fi-om tliat focus in tlie vernal season. The fireball of 1891. ,\pril 2, had a radiant of 29' + 55° ; tliat of 1876, April 9. at 17"-^ 57° ; that of 1874. April 10, at 19° -I- 57 ; thatof I89.3,April 15, at 1.5° -h 59'; and that of 1S77, May 30, at 20+58°. The various catalogues of meteoric observers contain other instances of brilliant slow-moving .4pril meteors from the same radiant in Cassiopeia. THE FACE OF THE SKY FOR JUNE. By A. Fowler, f.r.a.s. The Son. — On the 1st the sun rises at 3..52, and sets at 8.4 ; on the 30tli he rises at 3.49, and sets at 8.18. He enters Cancer, and Summer commenoes on the 22nd at 3 a.m. Few sunspots are to be expected. The Moon. — The moon will be full on the 2nd at 9.53 A.M., will enter last quarter on the 9th at 10.0 p.m., will 1)6 new on the Itith at 1.33 p.m., and will enter first JCNE, 1901.1 KNOWLEDGE 143 quarter on the iSrd at 8.59 p.m. The following are among the occiiltations visible at Greenwich ihirin;,' the mouth : — 9 Nnme. 1 c-S 1^ a i < s 1 .1 " .2 c •< i' ¥ o O ' o o d. 1> Jniie t M Sa-,-ijutarii 4-1 -'. 1 A M. III 1 ■> :>. l!> A M. 10.> '.15 .■!..W a27 210 17 21 .. 8 ci Crtprk-orni B A.C. 45.U .■i-j J.,W A X. m> lis :i.5t 21) 1 21 IS 20 21 .. i'i 57 7..i7 !• H. 101 94 ! i'.lS ;K)2 28;! il 7 ., 2i< w' Scorpii 4 1 11.151- U. 53 :i7 12.15 :!15 29 L 12 10 .. iS cu' Scorpii i-H ll..-»P.«. lou 8., 12.18 2o7 2W — Attention may Ix' speeially drawn to the occMiltation of tu' ami il' Scor[>ii ou the night of the SSth. The Planets. — Meivnry is an evening star throughout the month, reaching greatest easterly elongation of 24 'i'.t' on the Itith, and, apart from the strong twilight, is very favoumbly situated for observation. On the lOth, he sets Ih. oom. after the sun; on the l<>th, Ih. 4"nii. ; and on the ISth, Ih. 40ni. after the sun. On tlie iCth the planet will be to the snuth-west of Castor and Pollux, roughly at the same distance ffm Pollux tliat this star is from Castor. Venus is an evening star, having [lassed superior con- junction on May 1st. At the middle of the month she sets a little less than an hour after the sun, and at the end of the mouth almost exactly an liour after the sun. Mars may still lie watched in the early evening. On the 1st he sets a little before 1 a.m., and on the 30th about 11.20 P.M., his apparent diameter diminishing from 7"'2 to tj""2. On the loth the illuminated part of the disc will l)e 0'890, the phinet iiaving jassed iiuadratnreon May 'irttli. The path is direct, or easterly, through the south-castcin part of Leo. Jupiter inav be observed befoii' midnight throughout the month, risinij on the 1st a little before half-past ten. and on the 30th a little aft. .. 11 .53 41 IV. Sli. E. . 11 54 26. h— III. Sh. E. . 10 26 0 30tli I. Tr. I. .. 10 4 III. Tr. E. .. 10 49 0 1. Sh I . .. 10 4 0 27th— II. Sh. E. . 9 47 0 I. Tr. E. . .. 12 21 0 II. Tr. E. .. 9 ne 0 I Sh K. . 12 21 u Attention has been drawn by Mr. Crominelin to the speciallv interesting piieuomena on the 30th, on which date there will be a transit of the earth across the sun's disc as seen from Jupiter. Satellite I. will almost occult its own shadow on the planet, but as the shadow will be slightly the larger, a dusky ring may be expected to surround the satellite. Saturn is in Sagittarius, a little to the east of Jupiter. On the 1.5th, the apparent diameter of the planet will be 16 '8, and the major and the minor axes of the outer ring respectively 42 "4 and 17"'6. The ring is widely open, with the northern side towards us. Uranus is now fairly well placed for obseiwation, being in opposition on the 6th, but like Jupiter and Saturn, rather low in the sky. The path of the jdanet is a short westerly one in the most southerly |>art of Ophiuchus; it will be found to the west of the stars ^ and 5, roughly equidistant from them, and at a distance a little greater than that between the two stars. Ne|itune is in conjunction with the sun on the 21*t, and cannot be observed. The Stars. — About 10 p.m., at tlio middle ol the month, ('yguus will be in the east ; Lyra will be high up, a little to the south of east; and A(piila will be nearly in llie same direction, but lower. Near thc^ meridian will be Hercules. Corona, 0[)hiuchus. Libra, and Scorpio. Arc- turus will be a little west of the meridian. Virgo rather low in the south-west, and Li'o almost due west. (!ri)css CToIumn. By C. D. LococK, b.a. ■* Communications for this column should be addressed to C. D. LococK, Netherfield, Cambcrlcy, and be posted by the 10th of each month. .Solutions of May Prolileins. (Mrs. Hainl.) No. 1. 1. Ij to QB2, and mates next move. No. 2. Ki'li-niore. — 1. B to Kt2. If 1. . . P to R4, 2. Kt to Kt.^,. 1. . . P to B5, 2. R to Klcli. I. . . PxP, 2. Kt to QH. 1. . . P to I\t4, 2. Px P en passant. Tlie following are a.t ])rcsent the Iciiding scores in the Solution Tourney ; — • Tiri^iilii-serfii iminla. — S. CI. Luckeouk, J. T. Blakeniore, (x. W., C. Johnston, A. C. Challenger, W. Jay Tweidi/-xi'' piiiiitg.—J. Baddeley, H. Le Jeune, G. Groom, F. J. Lea, W. de P. Crousass, W. H S. M., F. Dennis, C. C. Massey, Eugene Henry, A. J. Head, J. Sowden, G. W. Middleton, E. Hunt, Vivien H. Mac- meikan, J. E. Broadbent, C. f!hild. Tii-fuhj-tiri' jjiiiiify. — Endirby. Tweiity-foiir jiohilx.—C. F. P., (L A. lAo-de (('apt), A. H. Mai-hell Cox, Alpha, H. Boyes. Tivcnfij-thirt; poin.ig. — A. E. Whitchousi', .1. .\1. K , \V. Nash, C. C. Pennington. Tirenty-tiro pninU. — F. A. Wileoek, who did not attempt the January ]iroblems, but has since scored the maxiinum number of points. All the above score .5 this month, with the exception of Endirbv, 4 (I point deducted for incorrect claim lor a second solution;, and A E. Whitehouse, 2. , CoEBKCT Solutions of both ju-oblenis have also been received from W. Boyd and A Kempster. Endirbij. — After 1. Q x Bch, K to Q3, there is no mate. . W. H. S. M. — The law concerning post-marks was stated very c'early before the competition began. There can be no doubt as to its interjuetation in the case you mention. F. 0. Wilhdmy. — April solutions correct; too late to acknowledge last month. W. H. (jirmlrij. — Ma.ny thanlcs. If is marked to ap[)eai- later in the summer. Hi KNOWLEDGE. [.TiTNE, 1901. W. Boyd. — Tour problem beginning with a check is not sufficientlv deceptive. In addition there is a T. Physiek. l,ondon 0 0 F. J. H. Elwtjll. Soathampton 1 1 S. P.issniore. London 1 1 H. Brewer, London ... 0 0 H. F. Cheshire, HustingA ... - - A. E. Tietjen. Loudon 1 1 P. How*-lI. London ^ 0 0 C. E. C. Tattersall, London ... 0 - W. T. Pierce, Kent 1 1 C. J. Lambert, Exeter 0 (t M. E. Moore. Bristol ... 1 1 F. P. Ciirr, Loudon ... 1 1 C. J. Woon. London 1 1 E. Emery. London 0 1 A. Cnrnoek, London 1 J Dr. Lowenthal, Liverpool .V 0 A. A. Bowle.v, Brighton i 1 J. Muserove. 1 eeds + 1 F. N. Br.mnd, Brijrht u i n T. H. Lambert. Manchester 0 0 E. C. Tumbail. London I 1 W. J. Greenwell, Newcastle .. n i F. H. Miles, Hastings 1 I, G. H. Harrison, Sheffield 1 0 S. Van Geld, r, Bath 0 1 H. Dovle, Eureiiiont 1 * F An*pach, London n * J. Foulds, llradford 0 (1 M. Michael. London 1 1 S. Keir, Lancaster 1 0 Dr Dei^hton, Cambridge 0 1 J. S. Brooksbank, Cumberland 0 * W. E. Vvse London 1 1, J. Nicholson, Neivcastle I 1 F. W. Flear, Huntington n n B. H. Philip. Hull ): 0 H. Erskiue. Brishron ^ 1 J. Hiirfiins, Cumberland n 1 VV. Bridger, Sussex 1 n P. K. Enelaiid, Liverpool 0 1 Dr. Duustan, London .. . . 1 n W^ Gleduill, Dacre, Bks. 1 1 T. B. Girdlestone, London ... + n H. Greenw'?ll, Newcastle 1 A H. G Lee. Bath II t F. C. Howell. Leeds 1 H. L. Bowles, London 0 S. jM. Cockin, Wakefield 0 T. M. Friedmerger, Hastings 1 i A. E. Greii, Birkenhtad II 0 T. W. Newman, London 1 1 J. J. Shields, Hull 1 1 T. E. Havden, London 0 0 \\ . D Ha wdon, Newcastle 0 II J. A. Watt. Hastinss 1 1 M. Jackson, Hull 1 1 H. D. 0 Bernard, Honiton ... n fl F. Stainsby, Middlesboro' I 1 F. Porchas, Bright in 0 0 W. Nixon, Newcastle ... ', 1 G. W. Williams, Essex .. n n C. W. Roberts, Bedford 1 0 Col. Chisholm, Cheltenham. 0 I C. J. B. Lowe, Manchester II A T. Taylor, Plymouth 1 D. Cock, Si>enuvmoor ... 1 G. B. Capel, Bath n 1 M. Holt, Manchester 0 1) G. V. Sutton, London 1 1 C. Cioft, BurleT-in-WTjarfOale 1 1 J. A. Green, London n II W. H. Burgess, Manchester ... 0 A Coi. Law, Gloucestershire I 4- C. Piatt, Carlisle tl J W. Mears, Torqmy 1 i Total ,11; Total 53i The final score is — South, 47 ; North, 43. The Sixth Anglo-American Cable Match took place on April liith and 20th. Fortunately Mr. Blaekburne found himself able to play after all, and the British team was greatly strengthened by the inclusion of Mr. Mason. As the Americans had won in the two previous years, it was of the utmost importance that their opponents should at least draw the present match and thereby prevent the Newnes Challenge trophy from leaving these shores for ever. This, after a hard struggle, they succeeded in doing, the score being as under : — Geeat Beitaix. T.T.S. America. J. H. Blaekburne 0 H. N. Pillsbury 1 J. Maiton ... 1 J. W. Showalt.T 0 F.J.Lee .. 1 J.H.Barry -'- D. Y. MiUs i A. B. Hodges H E.Atkins ... 0 E. Hymes G. E. H. Bellingbam . i H. Voigt ... W. Ward . i F.J.Marshall E. M. Jackson ... .1. S. W. Bampton Herbert Jacobs . II C. J. Newman E. P. Michell 1 C. Howell Later in the month a cable match between the American Universities and a team representing Oxford and Cam- bridge Universities likewise ended in a draw, the score being three games all. Mr. Lawrence won the City of London Championship (for the fifth time) without losing a single game, winning 18 and cb'awing 3. The order of the other prize-winners is not yet determined, but Mr. Herbert .Tacobs will pro- bably be second ; Mr. Ward, W<^, third; Mr. E. O. Jones or Dr. Smith, fourth ; and Mr. A. Curnock, sixth. Miss Finn has won the championship of the La'lies' Chess Club, Mrs. Fagan being half a point behind, and Mi's. Anderson third. For Contents of the Tbo last Nnmbers of " Knowledge," see AdYertisement pages. The yearly bound volumes of Ksowledqe. cloth ^It, 8s. 6d., post free. Binding Cases, Is. 6d. each ; post free. Is. 9d. Subscribers' numbers bound (including case and Index), 23. 6d. each volume. Index of Articles and Illustrations for 1S91, 1S92, 1S94, 1885, 1396, 1S97, 189S. 1899, and 1900 can be supplied for 3d. each. All remittances should be made payable to tbe Pablisber of " KsroWLEnoE." "Knowledge" Ajannal Babscription, througtaoat the world, 7s. 6d., post free. Communications for the Editors and Books for Review shonld be addressed Editors, " KsowLEnoE." 32 >, High Holbom, Lond.jn, W.C. JlLY, 1901.] KNOWLEDGE 1 ir. IllUSTRATED MAGAZI N E lMiEN€EJ-lTERATUMA^^ Founded by RICHARD A. PROCTOR. Vol. xxn.] LONDON: JULY, 1901. [No. 189. CONTENTS. ^ PAGK The Size of Ocean Waves. — IV. Bv Vait.han ConhMsii, D.?C.(VK-T.>, F. '?.>., F.G.?., F.B.G.S. (lUllslrtlted) .. 11") The Relative Speeds of some Common Birds. By Ch.iklks .V. WrrcnElL ... 1+9 Foun-Hor'ned Sheep. By R. I.tdekkkk (IlhtslraUd) . ir>0 The Stars near Nova Persei 152 Nova Persei and Surrounding Stars. {Plate.) Constellation Studies.— VII. The South Circumpolar Stars. By E. W.^lter iI.\rXDKR, f.r.a.s. fltluntntledj 152 Prof. Adams' Lectures on the Lunar Theory. By 1*. H. COWBLL ... l.")4 Letters : Thb Orbit op the Mooy. By Sir Samckl Wiies, B.\11T., M.D.. Lt.D.. F R s. ( Tlluxfroteil) ... ... l.'i! SrsspOTS AND Winters. By Alex. B. MacDowai.l (lllusfratpdj 150 PETEBlIINATlOy OF Xoos. By Wsi. Davie5 1.57 CtDCDS ox Mars. Bv T. R. Wabino ... l.'>7 The Ice Age. By W. H. S. Monck I.j7 Notes ].")S Notices of Books .. ... 15!) Books Received . Ifio British Ornithological Notes. Conducted hy Harry F. WiTBERBV, F.Z.S.. M.B.O.V. ... ... ... ... ... I (>0 The Insects of the Sea.— IV. Beetles. By aso. II. Carpenter, B.ec.(LOSu.) {Illustrated) ... ' 161 Standard Silver: ItsHistory. Properties and Uses.— III. By Kexest A. Smith, Assoc.R.s.M.. F.c..?. . ... ... 163 Microscopy. Conducted by II. I. Cross (niii.^t,-f,l,dj ... 16.") Notes on Comets and Meteors. By W. F. Denning, F.R.A.S. ' 1(50 The Face of the Sky for July. By A. Fowler, f.e.a.s. ... 167 Chess Column. By C. D. Locock, b.a IfH THE SIZE OF OCEAN WAVES.-IV. {ConcliuUnij article.) By Vaughax Cornish, d.sc.^vict.), F.fi..s., f.c.s., f.r.g.s., Associate of the Owens CoUeije. The diagram Fig. 1 is composed of two parts. In the upper we have a simple wave of length 300 feet and height 15 feet, and a simple wave of length .5.oO feefc and height 15 feet, which are combined in the thii-d line, giving a slightly irregular wave surface of which the average amplitude for the portion shown is about 16 feet, and the avefage distance from ridge to ridge is 300 feet. Shorter waves, however, flatten out more quickly tlian longer ones, so that after the wind has subsided the shorter will cease to be the more conspicuous wave, and the sea will pi-esent the appearance shown in the fifth line, an irregular swell with an apparent wave length averaging about 500 feet for the portion shown. For the purpose of this illustration I assume that the longer swell has not yet travelled completely beyond the shorter, as. of course, it will when sufficient time has elapsed. Fig. "J is a further illustration of the conditions wliicli (Ictoi'miiie the a))parent dominance of one wave, which, 1 tliinU, greatly mtliu-nc(^ Ihe record of average observed IcMgl h and height . In this diagram, which is dr.iwn ratiier rouglily, but not too roughly for the purpose in hand, the shorter wave, 150 feet long and 7^ feet high, is plainly visible on the third line throughout most of the distance, but is as plainly subordinate to a longer wave. The wave shown in" line 2 is 400 feet long and 20 feet high, it is not only longer than the wave in line 1 but is equally steep, and, therefore, so far dominates the shorter wave that an observer on board ship, who must concentrate his attention if he is to get results at all, measures only the crests A, B, C, D, the average interval between which IS 400 feet. The lower three lines of the figure show tli3 combin.ition of two same waves when of equal amjili- tude. The apparent wave length is now 150 feet. For the advancement by observation of our knowledge of ocean waves it is desirable that measurements of indi- vidual heights and lengths should in future be recorded, and the analysis into constituent waves attempted. The want of a fixed datura line will probably render such analysis imperfect, and the absence of fixed relation between the height and length of the components is a difficulty; nevertheless an approximate analysis could be made, and this would be a decided advance on the present condition of ailairs. We have here to deal with the measurements at present available ; these record the average size of the most conspicuous ridges seen from on board ship (reckoning amplitude as the vertical height from the trough to the ne.xt succeeding crest without reference to any datum line), and the average does not seem to differ much fioni ihe size of the longest of the steep waves rnniiiiig at Ihe time, which I propose to call the dominant wave. It has been the custom of obsei-vers as far as possible only to take measurements when the waves were fairly regular, and to avoid the very common condition indi- cated in Fig. 3, where the sea is agitated by short groups of higli waves with long " smooths " intervening. Let us now proceed to enquire what light the pub- lished observations throw upon the relation of the ob- served size of the waves to the strength of the wind, the distance through which it acts, and the size of the sheet of water. Tables given in the previous articles show the size of the waves in relation to the strength of the wind, the size of the waves being taken when the sea has attained its maximum roughness. In Paris' tabic the lengths of the waves are given. From those of De°bois and Wilson-Barker we can calculate the wave length roughly by multiplying the height by about 18. For small waves the number may be 15, for large waves 20. From the length of the waves the velocity is simply calculated by the formula: — Speed of Wave = 2j square root of longtli. (in feet ])er second) (■" feet) This formula, derived from the theory of regular tro- choidal waves, has been found to apply to the ob- served waves at sea with sufficient accuracy for our present purpose. We find that the speed of waves (i.e. the dominant form) in a storm at sea is much less than th.it of the wind. The long oceanic swells met with after a storm have, however, a velocity approaching that of wind in a strong gale; so much may be said without going into details as to the discrepancy between different records of wind velocity, assuming merely that the con- ventional " numbers ' expressing wind force are roughly comparable in the hands of experienced observers, and 146 KNOWLEDGE. [July, 1901. that the latest of tlie table velocities (that given by Captain Wilson-Barker) may l>i' advantageously substi- tuted for the earlier ones. Taking 28 feet as the average height of the waves in a violent storm in the ocean, and assuming that the average length is then 20 times the average height whiih the more in height limited bv we know to be approximately the case, the wave length would be 560 feet, and, the speed of the wave, therefore. 33 feet per second, 36 statute miles per hour. The wind will then be blowing some 60 miles per horn- relatively to an obsen'er stationary upon the water, but only 24 miles an hour relatively to the waves. Waves of gi-eater speed in the same storm would be subjected to a lighter wind, and a wave travelling 60 miles an hour would be in still air. It is not difficult to see, therefore, that the most conspicuous waves in the storm, even m phine mer. will not be the very longest which the wind may be supposed capable of directly creating. The growth in height of the longer waves is thus limited by the diminution of the power of the w'ind to press upon swiftly retreating form. The growth of shorter waves, on the contrai-y, is the circumstance that the slowly moving ridge of water, being subject to almost the full force of the gale, gives way if it become high and steep, bursting in a shower of spindrift. If we look at the waves raised by the wind iipon a pond we see that, commencing with wavelets about an inch long close to the windward shore, there is an increase in height and wave length as we recede therefrom. The waves at any point on the pond soon attain the maxi- mum dimensions compatible with their distance from the windward shore, and however long the wind may blow no further increase in their size takes place. The same phenomenon can be well seen on a lake or any such body of water not subjected to the distiu-bing effect of a swell. The following Tabic (TX.) shows the relation between o 5^ t^ CI -.T' c; ^1 w W3 t^ ^* 1^ t^ r: i^T c-i N »p c: o . c-j —» ccrcibw-^-rroihtbibowsr^dooociciciffiO lib do i-*: M "5 ip X LO c; t* ^ ira *-•: ~ c o ^ i.-: ri -? IN M o o w O o cc If 5* P !5' EH •3 d- 1 o yooooppopL-ocpoooino--o f J ^ i: 1* c; c; o .^ — r: -r- c -^ a: 00 o -^ o o -^ o ^3 -*« ; "t; C - ^ ~ = o :: — H a- o ^ =;; = = S E=. — CO'Cp__. J:^ gi,__ I. ■jr.'^'Z^-ZZ •^'5-Z -■- iJ '^ < ^ ■^ ■ =^ ."^ CJ ri« C o C to E! = : 5 -S^ 'Z '•% z -A ~ :=. t. ■-' ■: =M —i -•St &-^ 5 %. = :i^. i I Jl-i.v. 1901.] KNOWLEDGE. 11.7 tlie lieiglit of wjivcs and the " li wind aooordinsr to T. Stevenson. •ngtli of foti-li " of (lie It is taken from the be o ^ ■a 5 a 13 I ■% article Harljiurs, in the Encyclopoedia Britannica, IXth edition. Column 2 srives tho distance to the nearest shore in (lie direction from which the waves come, eolnmn .'J the observed heij^lit, .md columns 4 and 5 tl.e heights calculated from tlie empirical foniiuhc which best satisfy the results of observation. It required many years to compile this table, as it gives the observations of " the effects of heavy gales which could only be made at long intervals of time." The author goes space over which the wind is acting throughout in one direction, then, since wo have no sure means of ascertain- ing what that distance is, the notion of " length of fetcii " of wind is of little further use to us; if, on the other liand, we continue to note the size of waves in connection with the distance from land in tho direction from which tho waves are coming, we must not expect to find a continuance of such comparatively simple. relations be- tween this distance and the size of wave. Nevertheless iff is desirable to take note of this, which I may call tlu^ hiK/ili' of run, for since ocean waves do not quickly subside, when the wind ceases, tho train of waves may be subjected more than once to wind blowing over them in the direction of their moveinent. St o Jdly, 1901.] KNOWLEDGE. 153 home, sink lower and lower iu the north and disappear, whilst new lights rise to shine upon ns from the sonth. Bnt beside the disappearance of old friends and the coming into sight of stranger stars, the known stars that still remain to us adopt most unfamiliar atti- tudes, and these become more and more perplexing the further south we go. Lordly Orion stands on his head in the exact attitude of a little city Arab, turning ft cai-t-wheel ; the long procession of the zodiac, all in turn suffer the same inversion ; Pegasus alone, a topsy- turvy constellation with us, pursues his course across the sky with head upraised. Even the moon seems one of which, Canopus, is inferior only to Sirius. As the Milky Way sweeps through Argo, it enters Canis Major, which, though not. a large constellation, con- tains Sirius and three stars above tho second magnitude and throe more above the third. This belt of tiie sky, therefore, from Scorpio to Sirius, is by far the most brilliant in the entire hoavons, both from tho numbers of brilliant stars clustered within a narrow band and from the brightness of tho Milky Way. But beyond this belt wo find an altogether difTcrent state of things. Round the southern ])ole there are no star groups to rival tho Groat Bear, Cassiopeia, the XV XIV XIII XII I' • LUPUS XI IX CEN TAURUS. ,&•.■.:. ^\ . %#r ?- A ,„,; •^ ^ -WORMA ,;. >-■ CIRCINUS ^CRUk ' / •- VELA PUPPIS *fi J. MUSCA -fl CARINA •u :^> ri •V R P '? fV ■'■" ' "t' .: •. i™AN&ULUM.' ^C.CkAMn ^'"'' \ ''^'"^° *' xX^^/V-J-..^ (•'■■ •nVjAPUS_y \ V, .;fl ~ - V ', \PICTOR ^r'""""^. • ^Z. '^i iiMnji(iiii(ii(iiiiiiiiiiiiiiMMiiiiniiill<^iiiiOiitiiiiiiiiliiiiiiiii'iiTTTlii'i(^Miiiiiiiiniiiij((iiiiiiii.tii>iiriPHFiiiii^riiiiiH Jj.iiiiMjitiii>ni>ii"ii"ii"ii'i.i.Hiitiy(ifIlil'Miiiii iiiil^iiuiix M r ii nil I ii ii r>ifiii THE ORBIT OF THE MOON. TO THE EDITOES OF KNOWLEDGE. Sirs, — The present communication is intended to fill a gap which exists in all the popular books on astronomy. All those which I have seen contain nothing or little to enable the reader to obtain any idea of the courses of the moon in the heavens. For many years it was a puzzle to me, as it was to others, for I have never yet met with any one, except those who had a professed knowledge of astronomy, who was able to describe in an intelligible manner the course which the moon took in its circuit round the earth and sun. I was once at the sea-side with a gentleman who had just taken a University degree for which he had to pass an examination in natural science, and we got on the subject of the tides and moon ; he declared that he had not the remotest idea how the moon took its annual coiu'se. I therefore asked him to stand at a fixed distance from myself to represent the moon as I would the earth, and to hold his stick behind him as I was doing to trace our course on the sand as we walked on. Keeping his distance as if tied to me he was to walk quicker or slower, and thus he would be necessarily revolving- around me, whilst at the same time he was moving forward. His movement would not be in circles but in curves. This demonstration being on a plane is of course so far imperfect. The subject has of late come before me again when some young people during the Christmas holidays attended a lecture on the moon. They were shown the moon's phases in the usual manner by making it perform a circle round the earth; although this explained the varying phases of the moon, they saw for themselves that no such circle could really exist unless the earth were stationary. I made this more intelligible to them, as I have done to ot/hers. by drawing the two figures pictured below. I made a circle for the earth's orbit with the sun in the- centre, and divided it into twelve monthly parts for simplicity, thirteen being an awkward I'umber to deal with. I then made twelve marks opposite the different divisions to indicate the twelve full moons. This forms the outer circle. My young friends assented to it as correct. They also assented to my making twelve marks between these constituting Ihe inner ciiilc corre- sponding to the no n'loon or dark niooii II was now obvious that if these marks were correct the luminary must pass from one to another diuing the fortnight between them ; these, therefore, I joined, and the course of the moon was at once seen. I have heard persons a. — Earth's orbit. b. — Outer ch'cle of full moons. c. — Inner circle of no moons. a. — Orbit of E:irtli. h. — Orbit, lit Moou made by joining the poiJits. who have taken some little interest iu the heavens declare that this simple drawing was a complete revelation to them as they were so beset with the idea of the circular movement of the moon as portrayed in the books that they could not eradicate it from their minds. As before said this diagram is on a plane, and, therefore, imperfect; but a better demonstration may be made by taking a coil of wire such as is used in electric instruments, bending it into a circle and joining the two ends. When stretched out so as to elongate the coils the spiral may be regarded as showing more correctly the course of the moon. It must be also remarked that in my diagram there is no attempt at projjortion, for it would be impossible to draw on so small a scale a spiral so close to the earth's orbit as to be 400 times less distant from it than the space between the earth and the sun. Let me finally say I am no astronomer or mathe- matician, and, therefore, have no pretence to tread on their ground ; all I advance for myself is the fact that there being no account of the course of the moon in popular books, the reader being left in ignorance of this subject or often misled, I have found my description and drawing have made it intelligible to them, although of course in a very rough and imperfect way. Samuel Wilks. P.S. — Whilst inserting my letter the Editors inform me that there are astronomers who have fully discussed the question of the moon's path, and have raised ob- jections against the description which I have given, more especially as from mathematical reasoning this path is every wheie concave to the sun. — S. W. [The defect of the diagram to which Sir Samviel Wilks' attention was called lies in the simple fact that it is not drawn to scale, and consequently represents the path of the new moon as convex to the sun instead of concave. This concavity should not be difficult to comprehend if it be borne in mind that even at the time of new moon the chief motion is that of revolution round the sun, which it has in common with the earth. The velocity of flic moon in its orbit round the earth only amounts 1(1 3(M10 feet per second, while its a.veragc velocity in Its iiioticni round the sun is 18.6 miles per second. — Ens.] SUNSPOTS AND WINTERS. TO THE EDITORS OF KNOWLEDGE. Sirs, — The accompanying rough diagram I would offer for criticism: — a, h, >:, d, e, each shaded column represents the average number of frost days per winter at Greenwich, reckoning from September to May, during July, 1901.] KNOWLEDGE 157 gi-o\vth of spots (^first winter after minimum, to winter ending iu maximum yeai'). a', b', c', d', e', the same in thi-ee wiutei-s following maximum. The one set are all abuve average, the other all below. Alex. B. INLvcDhwam.. 70 (w 60 55 50 45 40 35 30 25 20 15 10 55 /'';'-; . '/. ' '/' "/. X ,„. v.... J '.■.■.i.,A a h r d e '44 '57 'tiS '79 '90 -'48 -'60 -'70 -'83 -'93 56-2 61-5 5(i-3 61 G 620 a' b' c d' e' '49 '61 '71 '84 '94 -'51 -'63 -'73 -'86 -'96 45 7 42 0 47-3 490 43 0 DETERMINATION OF NOON. TO THE EDITORS OF KNOWLEDGE. SiKS, — We live in a rather isolated disti'ict and, as we have no sun-dial, find it difficult to get accurate time. Is there any simple means, by the shadow of a pole or building, by which wc could tell exactly when it is noon .' Any suggestion you cau give us in this matter will be thankfully received. Wm. D.wies. Concord. Dominica, British West Indies, April 24th, 1901. [The exact detenniuation of time requires the use of insti-uments, but the Approximate time of noon may be ascertained by watching the coincidence of the shadow of a vertical rod with a meridian line drawa on level ground from the foot of the rod. The meridian line is usuallv formed by drawing a portion of a circle through the end of the shatlow some hours before noon, with the foot of the rod a.s centre, then marking the point on the circle where the tip of the shadow reaches it in the afternoon, and joining the middle of the arc thus formed with the foot of the rod. Several circles should be drawn, and the mean of the positions should be atlopted. Noon deteiTttined in this manner will be local apparent noon, and correction must be piade for the question of time in order to find the local mean solar time which should be shown by a wat«h. Several suggestions for observing the .sun were made by Mr. Maunder in Know LEDOE for June. 1900. p. 133. Ens.] CLOUDS ON MARS. TO THE EDITORS OF KNOWLEDGE. Sirs, — Your correspondent, Mr. E. Lloyd .Jones, has, in the April and .June issues of tliis magazine, stated some objections to my previous connuunication (Feb- ruary). I fear I sUitcd the question rallier bluntly when 1 said, " The atmosphere of Mais is thin, and consequently free from clouds." What I meant at the timo of writing wiis that the clouds on Mars are so rarely visible that they ai-e scai-cely worth recording. Mr. Jones will lind that this is the view of almost all our modern astronomers. As I stated before, my views ou the subject have hu-gely been gained from Mr. I'en-ival Lowell's hook on " Mars, " and should Mr. .Jones desire further infoi-mation I would refer him to this work. T. K. Waking. Liverpool. THE ICE AGE. TO THE EDITORS OF KNOWLEDGE. Siiis, — Some years ago you inserted letters of mine on the subject of the Ice Age. I hope the following additional remarks may also iind a place in your columns. The laLe Prof. Tyndall stated that what was requiied in order to account for the Ice Age was a better dis- tilling apparatus than at present. But this remark cannot be adopted without qualifications; for with a better distilling apparatus the aqueous vapour might be deposited in the form of rain, not snow. And, in fact, the Ice Age seems ia have been succeeded by a Rain Age, for 1 do not think that the melting of the snows will account for the very large amount of water which seems to have been then deposited on the land. The Ice Age and the Rain Age seem Xo have resulted from increased distillation under difi^erent circumstances. Air at a high temperature may contain much moisture, but it can hardly be deposited as snow. Air at a very low temperature contains very little moisture, and can hardly produce a snow-cap of any considerable depth. A heavy snow-fall only occurs when the tem- perature is little below freezing-point, but to produce such a heavy snow-fall two further conditions ai'e requisite : first, that the fall of temperature should Ije rapid, and secondly that the air should be moist. The latter condition in these regions requires that the wind should be from the W. or S.W. ; or at least that the conflict between the wind and one from the opposite quarter slioidd take place over this (lountry before the temperature h;is sunk too low. We then require a rapid fall of tiuiiperature a( a time when the mean temperature is near freezing-point and the air is moist. If the rapid fall takes place before this period of the year there will be a rain-fall not a snow-fall. If later the snow-fall will not be so lica.vy. The fall of temperatui-e dependent on the seasons does not vary with the eccentricity of the earth's orbit. The most favourable condition for tlic formation of a snow-cap at any particular place will, therefore, bo that the suns distance should increase most rapidly at the time of the year when the mean temperature is nearly at freezing-point. I mean, of course, before the winter. For when a similar state of things occurs in spring a rapid increase in the distance of the sun would be balanced by a like increase in the length of the day and of the sun's meridian altitude. Suppose then that we take a country in which tiie mean temperature sinks 158 KNOWLEDGE. [July, 1901. to freezing-point about the middle of November, an Ice Age woiild be most easily formed when the eccen- tricity of the earth's orbit was at a maximum, and the earth was in ajDhelion about tlie middle of August. This would be the period at which the cap would form most rapidly, but it would no doubt continue to increase in mass for some time afterwaixls, and the most exten- sive cap might be found to corres23ond with an aphelion not at midsimimer but at the^ autumnal equinox. I am not at present considering the competence of the caiise assigned by Dr. Croll for the Ice Age in the British Isles. I am only dealing with the dat« of the aphelion which would be best adapted for the formation of a snow-cap. Even with the present small eccen- tricity of the earth's orbit the periods of greatest heat and greatest cold are very perceptibly later than the longest and shortest days. With a more eccentric orbit this diilereuce w-ould probably be increased and the mean tempcratiu-e of England might not fall to freezing- point until a much later date than at present. But whatever this date might be, it is the date at which the sun's distance should be increasing most rapidly in order to produce a lasting snow-cap. W. H. S. MoNCK. Astronomical. — It is reported that the Harvard College Observatory astronomers, who have been at work in Jamaica, have obtained photographic evidence of the existence of snow on the siu'face of the moon. Details have not yet been received, but it is stated that changes have been detected on many of the moun- tain peaks, and the siniplest supposition is that the variable substance is snow. Further reports on the eclipse of May 18th state that good photographs of the corona were obtained by both Mr. Newall and Mr. Dyson, and that Mr. Newall also obtained good results with his gi'ating spectroscope and polariscopic camera, but failed to establish the rotation of the corona. The brightest parts of the corona showed marked polarization. Prof. Barnard's long exposure photographs were unfortunately spoiled by clouds. Count de la Baume Pluvinel, who also obsei-ved in Sumatra, appears to have been pretty successful, though he did not succeed in demonstrating the rotation of th(' coi-ona ; no Fraunhofer lines were detected in the spectrum of the corona. — A. F. I ■ I — Botanical. — The report of the Departmental Com- mittee on botanical work and collections at the Biitish Museum and Kew, together with minutes of evidence supplied by a number of eminent British botanists, has been published in the form of two Blue books, which contain matter of very considerable importance to all botanists. The Committee was appointed " to consider the ])rcsent arrangements under which botanical work is done and collections maintained by the Trastees of the British Museum, and under the First Commissioner of Works at Kew respectively; and to report what changes (if any) in those aiTange- ments are necessary or desirable in order to avoid duplication of work and collections at the two Institu- tions." The recommendations of the Committee are in favour of the union of the two herbaria, and of their being united at Kew, where suitable accommodation would have to be provided for them. It is considered advisable, however, that the fossil plants and the botani- cal objects exhibited to the public at the NatiU'al History Museum should be maintained, .the latter feature to be extended and developed as much as possible. — S. A. S. Entomological. — The subject of sound-production by insects continues to attract the attention of naturalists. A valuable paperon "The Stridulating Organs of Waterbugs" has been contributed to the curi-ent number of the Journal of the Qnehett Microscopical Club ( (2) VIII., pp. 33-46, pis. 3-4) by Mr. G-. W. Kirkaldy. He deals principally with the musical performances of the Corixidse. These little insects make a shrill chirping note, which has been attributed by several jirevious observers to the action of a " comb " of regularly arranged teeth on the front foot. But Mr. Kirkaldy maintains that this comb is drawn, not as previously supjiosed, across the edge of the face or beak, but across a special spiny, stridulating area on the opposite front thigh. The arrangement of the teeth of the " comb " varies characteristically in the different species of waterbugs, and Mr. Kirkaldy believes that the elaborated forms of the organ can be derived from the simple row of bristles found on the foot of the tiny Microneta or Sigara. The fully-developed musical instru- ments are confined to the male sex. Another important ])aper on this subject has been lately published by Dr. A. Haudlirsch (Ann. Hofmm. Wien., XV., pp. 127-141, pi. 7), who describes also stridulating organs on the thoracic segments of Reduviids and other land-bugs. — G. H. C. Zoological. — Mr. Lydekker's article on " Mammoth Ivory," which ajjpeared in Knowledge for July, 1899, has been republished in the Smithsonian Report for 1899, now just issued. In the June issue of the Proceedings of the Zoological Society of London, Dr. W. G. Ridewood discusses the structure and origin of the so-called " bonnet " of the southern right whale. This is a lai'ge horny excres- cence, worn into hollows like a much denuded piece of limestone rock, growing on the head of this particular kind of whale probably in the neighbourhood of the blow-hole. More than one somewhat wild tJieoi-y has been suggested to account for its presence. One sug- gestion is that it indicates the descent of whales from rhinoceros-like mammals: another that this species of whale is in the habit of rubbing against rocks in oi'der to free itself from barnacles, and thus produces a kind of com — although why on the nose alone is not st.at-ed ! Dr. Ridewood will," however, have nothing to say to these ideas, but considers that tlie stnicture is due to the fact of the horny layers which are produced all over the skin are not shed on this particular spot. This is satisfactory so far as it goes, but we still want to know the reason for the local retention of these layers and tlieir growth into a kind of horn. The brief description of the little known Equiis jfrzevalskii, as represented by a mounted specimen in the museum at Pai-is, in the same journal, cannot fail to be interesting to naturalists. Appai'ontly it may now be taken as certain that the animal in question is really a distinct species, and that in some i-espects at least- — notably the presence of " chestnuts " on all JCLY. 1901.] KNOWLEDGE. 159 fo'.jr limbs — it is more nearly related to the horse than to tho asses. The origin and evolution of the Australian marsupials are discussed at some length by Mr. B. A. Benslev in the April number of the Aiiifrirtui Xi/hj-ii/Zx/. In broad contrast to the views of Dr. Wallace, the author is of opinion that marsupials did not effect an entrance into Australia till about the middle of the Tertiary period; their an>-estors beintr probalily ojiossums of the American tyj)e. They -were theu ai-boreal : but they speedily entered upon a rapid, although shortdived course of evolution, during which leaping terrestrial forms like tho kangaroos were developed. The short period of this evolution is at least one factor in the primitive grade of even the most specialized members of the group. In the advance of their molar teeth from a tritubercular to a grinding type, the author traces a curious parallelism between marsupials and placentals. Taking opossums to have been the ancestors of the group, the author considers that Mr. Lydekker may be right in his view that marsupials entered Australia from Asia by way of New Guinea. On the other hand, there is nothing absolutely decisive against their origin being southern. In the May- issue of the same journal Dr. H. S. Jennings shows that the spiral revolution of many small swimming organisms is analogous to the revolu- tion on its own axis of a rifle-bullet, namely, in order to render them capable of maintaining a straight course. The degi-ee of Doctor of Science has been conferred upon Mr. Vaughan Cornish by the Victoria University, Jlanchester, in recognition of his investigations upon waves and kindred phenomena. j^ottcts of Boolts. "Adv.vsced Exercises in Practical Physics." By Prof.. Arthur Schuster, PH.D., f.b.s., and C. H. Lee.s, D.sc. (Canibridgt University Press.) 8.s. Illustrated. — It is surely an objection for a book which is to be used in a laboratory to be sent out with uncut edges, and we take this opportunity of .sugge.sting to publishers the desirability of cutting the edges of such manuals. The present book is a laboratory guide for students who, having already had some experience in practical physics, are taking up the subject for the examination for the degree of B.Sc. The course includes seventy-five diiferent exercises, and is therefore fairly extensive. It apparently has been difficult for the authors to know exactly how much " theory " to give in this book as an aid to the working of any particular exercise. Sometimes this aid is unnecessarily full, and at other times too slight. The account of errors of observation is good. The drawings are not very plentiful ; we may suggest one at least which might be useful in a new edition of the work, viz. : The metlu)d of support- ing a specific gravity fla.sk in a water bath by rubber bands. Incidentally we. may remark that the capacity of this bottle is referred to on page 62 as its volume. The account of methods of accurate weighing i* very well done in this section, an' student may profitably occujjy himself in working some of the interesting examples which are liiven. The book is admirablv illustrated, and deserves to find a large circle of students outside the class for which it apjjears to h.'ivr been specially prepared. 160 KNOWLEDGE. [July, 1901. 'The Miceoscopt of the moke coAnioxLT occmEiifO Stabches." By Professor Hugh Gait, m.b., cm., d.p.h. (Bailliere, Tindall & Cox.) Illustrated. 3s. 6d. net This is an unpretentious little rolume which aims at giving the analyst, student, and others who miy have to examine materials for adulteration, etc., a basis on which to work. For this purpose a number of photographs hare been taken with the aid of a microscope and reproduced in the book with the magnifications in diamefers eiactly stated. Starch grains are peculiarly unsatisfac- tory subjects from a phojogi'aphic standpoint, and the internal markings by which the student l» usually directed do not appear conspicuously in the photographs. We are not sure that the aqueous medium that was used for the specimens is the best mountant, and we have often found that the details of such subjects are better displayed in some media than in others. Still the bases for working and deduc- tions are sound, the contours and sizes of the various starches are at once apparent, and these, after all, are the principal features which must guide any comparisons or examinations. We believe that the book will be found an extremely useful one to those interested in the subject and possibly to microscopists generally, for starch grains are easily secured, and there is considerable interest attaching to their examination. "RoMASCE OF THE HsArENS." By Prof. A. W. Bickerton. (London : Swan Sonnenschein & Co. 1901 ) 5s. If an author's enthusiasm in behalf of a theory would influence opinion. Prof. Bickerton would surely persuade many to accept his theory of cosmical impact, which is really the subject of this volume. Finding astronomy " a chaos of facts " he claims to have converted it into a classified system, and to have explained the genesis of every type of celestial body. TTie leading idea is not diffictJt of comprehension. Two dark bodies are supposed to come into grazing collision, with the result that the grazing parts are sheared off to form a third body, the mass of which may be so small that the molecular velocities of its particles will cause its dissipation into space ; while the two " wounded stars " become variables or possibly form a double star. In its further development, however, when the author pictures collisions of nebulfe, star clusters, meteoric swarms, and cosmical systems, it becomes much more intricate. We must confess that we find the idea of all this collision in an orderly universe quite as repellant as the author appears to find the commonly accepted views as to the degradation of energy and the coming ''uni- versal death " : how he escapes from the latter can hardly be expressed in a few words. Keedless to say, the theory is considered to be absolutely demonstrated by the known facts of astronoaiy, but much of the evidence brought forward is far too slender to be convincing. It is by no means certain, for instance, that the authors interpretation of the spectrum of Xova Aurigie is justifiable, and the statement that the masses of the two supposed colliding bodies in that ease were respectively eight thousand and four thousand times the mass of the sun only makes us doubt other numerical results. In spite of frequent repetitions and its somewhat florid style, those interested in speciJative exercises will find the book readable enough, though, iinlike the author, they may not regard " probably " and " possibly " as evidence amounting to demonstration. BOOKS KECEIVED. The Complete Works of John Keats. ^'ol. Y. F.dited by H. Buxton Forman. (Glasgow : Gowans & Gray.) Is. net. The Use of Words in Seasoning. Bv -Alfred Sidgwick. (A. and C. Bkck.) 7s. 6d. net. The Mediterranean Sace. (Contemporary Science Series.) By G. Sergi. (Walter Scott.) Illustrated. 6s. " A Sandbook of Ptirogrnphy. Bv Mrs. Maud Maude. (Dawbam & Ward.) Illustrated. Is. 6d. net.' Papers on Mechanical and Physical Suh/'ecfs. By Osborne Reynolds, f.e.s., m.i.c.e.. il.d. Vol. 11. 1881-1900. (Clay.) Illustrated. 21s. net. Select Pibliographti of Chemistry, 1493-1897. By Henry Carrington Bolton. Section VIII. — Academic Dissertations. (Smith- sonian Institution.) Fergusson'a Surveying Circle and Percentage Tables. 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MiTlStt ^ ORNiTHOLOGfCAft -.-» 1- NOT£S.-r.___j Conducted hy Habey F. Witheeby, F.Z.S., u.B.O.U. Stabling or Nuthatch ? — Much has been said lately in praise of the Starling. To the agriculturist the Starling is without doubt a benefactor, owing to the enormous number of grubs it consumes, and its increase in this country within the last few years should prove a blessing to the farmer. By the ornithologist, however, this great increase can hardly be regarded favourably, notwithstanding the interest attaching to the fact itself. The Starling is an amusing bird, but you can have too much of a good thing, and if the Starling continues in his 1901.] KNOWLEDGE. IGl atrsiressive lureer. he will soou drive awny other more interesting aiid attraotive birds whieh stand, I venture to say, nearer to our affeetious than he does. In the >i'ew Forest, for instanee, the Starling has inereased enormously during the last few years. Everywhere aliout the woods you will tind him and his young screeeh from all the •• likely " holes iu the trees. " The truth is that, with all his clumsiness, the Starling has a keen eye for a good home, and he calmly ap]iro|iriates, or fights for if necessary, the l)est nesting holes. Tlie result is that the Nuthatches ;ind the Great Tits, the former esi>ecially. have some difficulty in finding nesting sites. One would think there was a limitless sujijily of nesting holes where there are so many old trees, but every one who has examined such holes knows that a good iiianv conditions have to be fulfilled befiire a ri'ally dry comfortable place for a nest is formetl. In thi' New Forest the Nuthatches have certainly decreased greatly during the period in which the Starlings have been increasing Personally I would far rather watch and hear one Nuthatch than a hundred Starlings, but what can be done? — H.\rry F. Witheruy. Gloisi/ His in Counti/ Durham. (The Is'aluralisf, ilav, 1901, |>. 149.") Mr. T. H. 'Xelson records that a (Jlossy fbis, an accidental visitor to tJreat Britain, was shot near Stockton-on-Tees on November 25th last. Ah Obsercational Diarii of the Uabils — moslli/ ilomestic — of the Great-crested Grebe (Podicipes crisiatus). Bv Kdnuiiul Scions. (Zoologist, May. 1901, pp. 161183.) Mr. Seioiis has aheady contributed to the pages of our contemporaiy two |)apers. to which we drew attention (referring to the Xiglitjar and the Stone Curlew). similar to the present one. This article, however, is more literary in style, and is therefore more interesting reading, withowt any deterioration iu seientitie value, than the previous contributions, which were somewhat wearisome by reason of lluir excess of detail. Mr. Selous has made a number of interesting observations. regarding especially the nesting and pairing habits of the Grebes. He comes to the conclusions that the birds pair on the ne.st itself; that the male, in addition to helping the female in building, constructs a platform of weeds at some distance from the nest whereon to re.st ; and that the bird.s usually attack their enemies from under the water. Mr. Selous' theories are less happy than his records of facts. All contributions to the column, either in the way of notes or photographs, should he fonvarded to Hakry F. Witherby, at 10, St. (Tirmiins' Place, Blackheath, Kent. THE INSECTS OF THE SEA.~IV, By Geo. H. Carpenter, b.sc.(lond.), Agsistant in the Mit^fiim of Science and Art, Duhlin. BEETLES (continued from pafje 116). Another well-marked marine genus of Rove-beetles is Diglossa or Diglotta,|| in which the feelers are relatively long, and the palps of the first maxillae most remarkably so. while thosci of the second maxillae are re- presented only by long bristles. Two species — D. merm, Haliday (Fig. 7). and 1). .unuatlcoUis, Rev, inhabit the British, Irish, French, and Dutch coasts. Elsewheie, Diglotta seems only known on the island of Celebes. In these beetles the wings are reduced, often to very small vestiges. Consequently they do not fly but run actively about in the sunshine over rocks and shingle. D. fiinuaticolliK is said to escape submersion by biiirowing in the sand just above high-water mark in company with the Bledii before mentioned. The beetles make little A. H. Haliday. '' Xotes about Cillenum and a sub-marine Species of Aleocharida;." Ent. Mar/., IV., 1837, pp. 251-3. Also yat. Mist. Ret., Vol. II., 1S.56, pi. .3: and Vol. III., 1857, p. 20. G-. C. Champion. " Some Remarks on the two Species of Diglo-^sa occurring in Britain." Ent. Mo. Mag., X.XXV., 1899, pp. 2«')-5. B. Torulin. " Notes on the Habits of Diylolta sinuaticollis." I.e., p. 2yo. holes about .1 inch dcc|), and dwell therein singly or in pairs. The larva, described and figured by Haliday, has a very large head, and long legs, which are remarkable iu possessing three-scgnf.Mitcd feet (Fig. 6). Fig. (). Fig. 7. Fig. 6. — Qvah oi Diglotta mer.ia. (After llulidiy.) Magnified 20 times. Fio. 7. — Diglotta mersa. Magnilieil 20 times. One other genus of marine Rove-beetles must be men- tioned— Micralymma. The European species. A/, brevipeime, Gyll. (Fig. 8), which occurs on the British coasts, and northwards on tlte Continent from Franco to Scandinavia, may be recognised by its comparatively short and broad form. The surface of the body is densely pitted and very finely pubescent. As in Diglotta the wings are much reduced. The insects may be found lurking in crevices of the rocks or walking about on the stones and shingles usually below high-water mark. They are believed to hunt and feed upon the spring-tail Anuridn mnrifiina, which was referred to in a previous article of this series. A good account of the form, trans- formation and habits of this little beetla was given more than thirty years ago by Laboulbcnc.*[ He found that, Fig, 9. Fio. S. Fw. 10, Fia. 8. — Micralymma brevipenne. Magnified 10 times. Fio. 9.— Grub. (After Laboulbene.) Magnified l.j times. KlO. 10.— Pupa. (After Laboulbene.) Miignilleil 12 times. even at low water the insects were reluctant to leave their hiding-places, and that they made their way over the rocks rather slowly, hardly lifting the large hind-body from the ground. When taken in the hand they re- •" A. Laboulbene. "Surles Mceurs et TAnatomie de la Micralymma brevipenne." Ann. Soc. Ent. Ji'rance (.3), VI., 1858, pp. 73-110, pis. I.-III. 162 KNOWLEDGE. [Jdly, 1901. warded their captor witli " une odeur tres mauvaise et tres penetiante.' The grub of Micralymma is more lively than its parent beetle. It is elouyate in form, with the legs short, stout. and spiny; the tubular process at the hinder end can be bent downwards to act as a false-foot or pro-leg (Fig. 9). The pupa is a most wonderful creature, with its armature of long bristles that doubtless serve to en- tangle air-bubbles for breathing (Fig. 10). As might be expected, the Ground-beetles (Carabidse)— those active, predaceous, swift-running insects, which lurk commonly under stones and in such places — are well re- presented by the sea-shore. Space would fail us to enumerate the sand-dwelling Ground-beetles that may be met with above high-water mark. Several kinds of Dyschirius, for instance, small, dark, shining bron?y beetles, with the fore-shins flattened and strengthened to serve for digging, abound on our coasts. They burrow into the sand in pursuit of the Rove-beetles of the genus Bledius mentioned above and ruthlessly devour them. There is a large group of small Ground-beetles — the Bembidiiua — which frequent damp places, and are in- deed semi-aquatic in their habits. The most character- istic structural feature of this group, the vei-y shoi-t and pointed terminal segment of the second maxillary (labial) palp (Fig. 11, L. p.), is found also in the Haliplid», that family of true water-beetles which is most nearly allied to the Cax-abidfe. The very niunerous species of Bem- bidium are the delight of the specialist, and the despair of the average beetle-collector. Several of them may be found on the sea-shore, but they seem to keep out of the . reach of the tides. There is an allied genus, how- ever— Lymnaeum — a species of which, L. iilr/ropiceum. Marsh, occurs locally on the south coast of England and in the Isle of Wight, lurking under stones and shingle, below as well as above high-water mark. This little beetle inhabits also the French coast and the shores of Dalmatia and the Crimea. The most remarkable discontinuous range of this species is analogous to that of its genus which occurs in Europe, the East Indies. California, and the Kurilo Islands near Japan. Fig. 11. — Cilleniis lateralis. M;igni6od 10 lime?. L, sfcond maxillffi (labium), magnified 20 times, (p, palp.) Still more specialized for a marine life is CiUenus lateralis, Sam. (Fig. 11), the only species of its genus, distinguished from Bembidinm by its relatively shorter feelers and parallel-sided elytra, which ai"e of a pale, sandy colour with dark markings, the large head and fore-body being shining bronzy green. Cillenus occurs at many points on the British and Irish coasts, some- times beneath stones, sometimes on the sand, but almost always below high-water mark. Its continental i-aiigc extends northwards only to Holland, but southwards as far as Portugal and Morocco. It is remarkable that while British specimens of this beetle are all wingless, those from southern Europe are occasionally winged ; evidently the species as a whole has not entii-ely lost the power of flight. At low water numbers of Cillenus may be found running in the sunshine; when the tide rises they retire under stones, or dig holes between one or two inches deep in the sand. In such shelters they survive in safety their immersion twice every day. A. H. Haliday, in the paper to which reference has already been made, gives a vivid account of the habits of Cillenus as observed by him on the Co. Dublin coast in the year of Queen Victoria's accession. " They pi'ey upon saiidhoppers (Talitrus), seizing them by the soft part of the underside, and, in this way, are able to master game many times their own bulk. Sometimes three or four beetles may be found in concert, attacking a saudhopper of the largest size. The tide retiring has scarcely uncovered the sand when these little depreda- tors are abroad from their hiding-places and alert in the chase." The grub of Cillenus has been described by Fairmaire. It has short legs and a very large head with long, formidably toothed mandibles. Another group of Ground-beetles with marine repre- sentatives are the Trechina — a tribe allied to the Bembidiiua. but distinguished by the elongate terminal segment of the labial palp (Fig. 13, L. p.). The species of the large genus Trechus live mostly in dark concealed situations, under stones, for example,' or in burrows along the) banks of streams. One of them, T. lapidoxus, Dawson, occurs just above high-water mark on the sea- coast and along the shores of tidal rivers. But the small beetles of the allied genus Aepus are perhaps the most characteristically marine members of the whole family, and, indeed, of the entire order of beetles. Small as these beetles are, 2 mm. (about yV inch) in length, their aspett when seen with a moderate magni- fication is striking and not easily forgotten (Fig. 13). The relatively immense head, larger than the forebody shield, and the truncate abdomen, broadest at its hinder end and only partly covered by the wing-cases, give the insect a Tiiost characteristic appearance. Both the European species of Aepus occur on the British and Irish coasts. J. w^a/■(;«^^s■ (Stroem.) has a deep dorsal fur- row on the forebody. and rather long parallel-sided wing- cases, while A. Euhiiul. Laboulb., has an indistinct dorsal furrow and shorter wing-cases widened behind. These insects both qccur on the French and Spanish coasts, and there is a third species on Madeira, and another far away in Chile. They have not been found north of Denmark, and it is remarkable that they seem to be absent from the newest part of our own coast line — from Yorkshire to Sussex, the region by which our island was in Pleistocene times joined to the European continent. While the I'ange of most of the shore- haunting spring-tails points to an old continental coast- line stretching from our area towards the north, that of Aepus. and, as we have seen, of most of the marine beetles, indicates the former extension of the old land to the south and south-west. Aepus is clearly a very ancient genus, and it is possible that these beetles were amongst the first members of our present fauna to reach our area, belonging as they clearly do, to the south-western (Lusitanian) group, whose restricted dis- tribution shows them to be the oldest animals surviving in our islands. JtLv, 1901.] KNOWLEDGE. 163 Several points in the struct me of Aopus deserve a l^issing mention. Wings seem to bo quite- .ibsciit. The widened fore-shin, as in several other ground-beetles (in- %M^ Fio. 12. Fio. 13. Fio. 12. — Gmb of Aepi'.s marittus. (Afler Wc^twood.) Miit^nilioil 20 times. Flo. I'-i. — Aeptis Bohinii. JIaguilied 20 times. L, second umxillie (labium), luagiiified 40 times, {p, palp.) eluding Cillenus), has a deep bristle-fringed notch to- wards its far end ; this serves as a comb for cleaning the feelers, which can be drawn through the notch so that particles of saiid are removed by the bristles. The com- pound eye of Aepus is composed of a relatively small number of circular facets ; the eye in marine insects is frequently thus, instead of being built up of an immense number of hexagonal facets. Behind the facets, accord- ing to Prof. Miall, is situated a concave plate with a circular opening; "the form of this plate,' he writes, ■' suggests that it may be employed as a kind of pin-hole camera. " Another interesting fact discovered by Prof. Miall and Mr. Hammond, is the presence of a pair of large air-sacs at the binder end of the abdomen in Aepus; these "are no doubt useful during prolonged submersion.' These beetles are provided with long bristly hairs, which, as Audouin** noticed nearly seventy years ago, serve to entangle air-bubbles when the insect is submerged. " If," he wrote, " one transfers the insect directly from the air into sea-water, one notices that each of its hairs holds a little layer of the surface film, which forming at first tiny spheroids soon unite into a little globule which surrounds its body on every side, and which, despite the agitation resulting from the insect running under the water .... never escapes. Our insect always can'ies about a little layer of air, and when it hides beneath a stone, it finds itself at once in the condition of insects living freely in the atmosphere." Coquerelft made some experiments as to the length of time which Aepus can remain under water. Their habit when the tide rises is to take shelter beneath stones and remain there till the ebb again sets them free. Coquerel found that when im- mersed under artificial conditions for a very long time ■' they always finally fell into a state of apparent death. •• J. V. Aurlouin. ■■ Observations but un lasccte C'oleoptere i|ui passe line prandc partie de sa vie sous la Mer. " Kouv. Ann. Miis. Hint. Nat., III., 1833, pp. 117 127. t+ C. Coquerel. " Xote pour servir ii I'lri.stoire de lAepus Kobinii et description de sa Larve." Ann. Hoc. Ent. France (2), VIII., 1850, pp. 529-532. I have kept them thus," ho writes, "for eighteen hour? under water. I believed them dead, but having placed them in the sun on a sheet of paper, Ihcv revived after some minutes and began to run about as before." Like its parent beetle the gnib of Aepus has a very large head, armed with sharp, strong mandibles, and is very active in its habits when the tide is out. The hairy covering wherewith it is provided hclp.s to entangle air- bubbles. Both beetles and grubs are believed to prey on small molluscs, such as Rissoa, in whose company they are often found. There is something fascinating in the study of the life of these small beetles, spending, as they must, the greater part of their time under stones on the sea bottom, wait- ing for the fall of tho tide to allow them a few hours' activity in tho air, which is, after all, their true element. The observer on the shore, as he watches tho breakcirs rolling in at tho flood, may well give a thought to tho tiny insects, safe in their hiding-places far beneath the restless waves, waiting there patiently until the ebb shall rcloasc them once again from their watery prison. STANDARD SILVER: ITS HISTORY, PROPERTIES AND USES. 11 1. By Ernest A. Smith, assoc. r.s.m., f.c.s. It is well known that silver wares, when exposed to ordinary atniospheric influences, soon become disfigured by blotches of tarnish, due to the action of the sulphur in the air, and in consequence require to be repeatedly cleaned to present a bright appearance. This being one of the drawbacks to silver goods a few remarks on this subject are not without interest, as the sui'face will become perfectly black in a few months time if continual cleaning is neglected. Some interesting directions for the care and cleaning of silver-gilt plate are preserved with the chiuch-plate of Stinsford, in Dorsetshire.* The directions, which arc dated June, 1737, are given by Paul Lamerie, the silversmith who made the plate. They run as follows : — " Clean it now and then with only warm water and soap, with a Spunge, and then wash it with clean water, and dry it very well with a soft Liiuien Cloth, and keep it in a di-y place, for the damp will spoyle it." The instructions given by tho silversmith who made the plate for Carlisle Cathedral in 1679 may be com- pared with the above extract as they are equally worth attention. " Be carefuU," he says, " to wipe it with a clean soft linnen cloath, and if there chance bo any Staines or spotts that will not easily come off with a little water, the cloath being dipp'd therein, and so rubb the flagons and chalices from the topp to the Bottome, not cross wise, but tho Bason and patens are to be i-ubb'd roundwise, not acrosse, and by }ioe means use either chalkc, sand, or salt." These last words cannot be too strongly emphasised, as much damage is frequently done to silver plate by excessive rubbing and the use of injurious cleaning materials. The simple directions given by Paul Lamerie and his brother silversmith still serve as a good guide for cleaning plate. By the adoption of the following process it is statedt that largo stocks of silver articles may be protected against atmospheric influences and will remain as bright as when first new. » Quoted by Cripps, " Old Englisli Plate," 0th Kdit., 1899, p. lO. t "Jeweller and Metalworker," \'ol. XX\'I. (1900), p. 102. 164 KNOWLEDGE. [July, 1901. The process consists in coating the wares with a thiu solution of collodion varnish, diluted with spirits of wine to a thin fluid. The articles should be slightly warmed, and the varnish applied by means of a soft white bristle brush, and on the evaporation of the spirit a thiu transparent film of glossy substance is left behind, which preserves the brightness of the metal, and dis- penses with the constant labour otherwise required in keeping the articles fresh and lustrous. As a thorough safeguard against tarnishing it is advisable to paint the articles more than once. The varnish is easily removed by means of warm water. Articles which have become very much tarnished may be restored by carefully rubbing them over with a clean piece of soft cloth wetted with a dilute solution of potassium cyanide (about 1 oz. to 1 quart of water;, and then well rinsing them in clean water when the silver apiDearauce has returned. Owing to the want of sufficient data it is somewhat difiicult to ascertain the total quantity of standard silver prepared annually in the United Kingdom, but an approximation to this quantity may be obtained from data published in the Annual Reports of the Royal Mint. The following figures, taken from the most recently published Mint rejjort, gives the total cjuantity of standard silver prepared in the year 1899 for the pur- jjoses of coinage and medals, and also the quantity marked at the Assay Offices of Birmingham, Sheffield, and Chester. Quantity of Standard Silver prepared at the Royal Mint in 1899. Oiuices. For Imperial Coinage (925 standard) ... 1(1,677,155 Fur Colonial Coinage (92.5 standard) ... 251,531 For Colonial Coinage (800 standard) 5,74;?,(i57 For War Medals (925 standard) ... 52,0J5 Total 16,724,358 or 512 Tons. Assay Office Returns for 18119 (Hint Report). Ounces. Silver marked at Birmingham ... ... 2,823,525 Silver marked at Sheffield 1,323,917 Silver marked at Chester... ... ... 741,044 4,888,486 or 149^ Tons. No official returns are made of the weight of silver marked annually at the Assay Offices of London, Scot- laud, and Ireland, but the following figures arc given by RedmanJ for 1898. Quantity of Silver marked at otlier Assiiy Offices in 1898. (Redman.) London Kdinbm-gh trlasgow Dublin ... Total Ouuces. 2,103,652 15,413 15,321 8,123 2,142,509 This latter quantity added to that marked at the Assay Offices quoted above gives a total of 7,030,995 ounces (215 tens) of silver used for industrial purposes. It may be remarked that the weight of foreign silver wares which are imported and marked in this countiy is included in (.his total, but the amount is comparatively small. After making allowance for the quantity of standard silver used annually for the manufacture of small aa-ticles which are exempt from Hall marking, a total of twenty- J " Hall Marks," Redman, 1900 Jidit.. p. 131. two and a half million ounces or about 689 tons would probably be a fair approximation to the total quantity of standard silver prepared annually in the United Kingdom. By an Act of Parliament passed in 1867 (30 and 31 Victoria, c. 90,- s. 1), annual licences must be taken out by every dealer in silver articles in respect of any shop, and by evei-y hawker or pedlai', a penalty of £50 being imposed for dealing without licence. For silver wares above 5 dwts. and under 30 ozs. in one article the licence is £.2 6s. Od., above 30 ozs. £5 15s. Od. In order to prevent the manufacture of spurious plate, the law requires that the quality of the metal of all silver wares, with certain exceptions, shall be determined by assay at offices duly authorised for that purjiose in various parts of the Kingdom, and that if it be found equal to standard it shall be stamped at those offices with a series of marks, but that if the wares are found to be below standard they shall be broken up and the silver returned to the owner, who is to be charged a penalty of 6d. per ounce. The marks employed denote the quality of the standard, the place of assay, and the yeai'; the law also requires that all wares sent to be assayed must bear the maker's mark. The name of the maker is indicated by his initials; the standard of 11 ozs. 2 dwts. (925) by a lion passant; and that of 11 ozs. 10 dwts. (959) by a lion's head erased (i.e., without the body) and the figure of Britannia, except at Birmingham and Sheffield, where Britannia alone is used ; the place of assay is indicated by heraldic arms, and the year of assay by a letter, which is used throughout the year and is changed every year. Duty was formerly charged on all silver wares, the payment of duty being indicated by the sovereign's head, but this has been omitted since 1890 when the duty was abolished. At the present time there are four Assay Offices in England, for which the arms are as follows: — Birmingham .. An anchor. Chester ... . . A sword between three garbs. London... ... A leopard's head (the arm of the Goldsmiths' Company). Sheffield A crown. Formerly there were nine Assay Offices, but those at York, Exeter, Bristol, Norwich, and Newcastle-on-Tyne have been closed, probably on account of the ti-ade being transferred to other centres such as Birmingham, Coventry, Sheffield, and London. There are two Assay Offices in Scotland, one in Edin- burgh, and one in Glasgow, where a series of marks corresponding to the English is used, but the standard 925 is indicated by the thistle, with the addition of Britannia m the case of the standard of 11 ozs. 10 dwts. The arms of the Scotch Assay Offices are : — Edinburgh ... A castle with three towers. Glasgow ... A tree growing out of a mount, with a fish and bell. The office at Glasgow has not adopted the marks prescribed by the above statute, but uses the Hon ram- pant instead of the thistle to denote the standard. In Ireland the assaying and marking of silver plate is restricted to Dublin, where a series of marks corre- sponding to the English is also used. The place of assay is indicated by a figure of Hibernia, and the standard, which is 11 ozs. 2 dwts., by a harp crowned. No silver wares of the " new standard." 11 ozs. 10 dwts., are marked in Ireland. Jtn.Y, 1901.1 KNOWLEDGE. 105 There arc no doubt some objections, as Cliaffers rc- ni.-irks.§ to the principle of compulsory assaying and marking of gold and silver wares. In this country, how- ever, the svstem has existed substantially in its present form since the reign of Edward I. Without speculating on its origin, and while making due allowances for its defects, it is est.ablished that it has resulted in tl'c creation and maintenance of a high standard of excel- lence for all British assayed wares, which has not only raised the reputation of British workmanship at home and abroad, but has also created a large amount of private wealth readily convertible into n\oney l)y reason of the g»larantee of value which the Hall-marks afford. Conducted by >r. I Cross. Rr-irm.RT'* Finf: Adiustmfnt (lontinned). — Since the appearance of the June number, Reichert has written stating that for each turn of the milled head controlling his new lever form of fine adjustment, a movement of '01 m m is produced : in his ordinary system of direct-acting screw, the rate of movement per revolution of the milled head is -3 m m. It will be seen that the rate of movement is three times as slow with the new fine adjustment. The new arrangement al-so permits of the use of coarse screws, which are obviously not so liable to wear as fine ones, and the whole of the mechanism is of steel. The entire construction is undoubtedly thoroughly sound FiG.l. — Sectional view, li.li', lever arms; j, point of contact with lever» controlled by screw a-, b, j)oint which communi- catee tlie movement from levers through semi-circular connec- tion c, f. Fig. 2. — External appearance, li, h. ful- crum of lever arm<. position that the house of Zeiss does in the optical world should have devised an improvement in such an important part as the fine adjustment. simple in design, and exceedingly is a distinct improvement to tbe mechanically, yet very efficient practically. It Continental stand. Zeis.-'s Fine AaitT^TMENT. — This is fitted to a new stand for photo-micrography and projection only, and in actual working is exceedingly steady, sensitive, and soft to the touch. The stand to which it is applied is arranged for use with Zeis-s's new Planar lenses, which work without eye-pieces, and are intended for photographing large objects, there being sufficient room on the stage for an object 160 mm iii diameter ; and, on the other hand, it is designed to work for projection or photography with objectives of the highest aperture and power. It is extremely gratifying to find that a firm occupying the § Chaffers. " Hall Marks on Plate," 8th Edit.. 1S96. p. 4.3. Fig. 3. — Sectional Views of Zeiss'* Improveil Fine Adjustment. The slowest fine adjustment they made previously gave for each turn of the milled head -25 m m ; in this new one a move- ment is produced of ■<)\ m/m for each revolution of the milled head, that is, it is six times as slow as the ordinary pattern. This in iteelf is an immense advantage. Fig. 4. — K, Controlling Milled Heads of Fine Adjustment. (For description see t<'xt,) It will be noted that the two controlling screw heads are parallel, and instead of being placed at the to]) of the limb, as is usual in Continental models, are set ou either side of the limb of the instrument. They are small in diameter, so that when low powers are used they can be revolved rapidly between the fingers. The drawings are self-explanatory. It will be seen that the movement is affected by a cog-wheel system. The endless screw E operates tbe cog-wheel S,, causing the long screw 51 to rotate, the reactionary effect being produced by the spiral spring U, To prevent the over-turning of the screws, a cog, S,, is provided, and this travels up and down on the pin G ; stops are fitted A, and A„, which come in contact with C, and C, when 16G KNOWLEDGE. [Jl-LY, 1901. the fine adjustment is carried to its limit, and thus undue strain is prevented. The construction presents features of originality and ingenuity. Every care has been taken to obviate unequal pressure, and consequent deterioration, and the whole mechanism is built in an extremely solid and workmanlike fashion. Stringer's Fine Aciustjient (made by W. AVatson & Sons). — This is, to some extent, an amplification of Watson's Standard pattern. Fig. '). — Stnnger'fc Fine Adjustment, showing sectional view of triangular fitting bar, points of contact, body tube, coarse adjustment milled heads, &c. Fia. 6. — Sectional A'ion- of Stringer'.* Patent Fine Alljll^tment. An examination of the drawings showinar the cross section of this fine adjustment wiU at once reveal that it is made in a very substantial manner. The bar E, which is cast in one piece with the limb, is triangular in shape, and fitting exactly round it is a sleeve in which are grooved the dovetails that receive the body of the microscope. The movement is effected by a lever of the second order, which operates by pressure upon a steel revolving pin A. This pin is mounted between two arms that are continued down- wards, and are part of the sleeve fittings of the fine adjust- ment, the fulcrum being at B. It will be seen that, contrary to the usual custom, the body is drawn downwards by the lever, and upwards by the spring D. A screw is provided for regulating the tension of this re- actionary spring according to the angle at which the microscope may be inclined. Due provision is made for adjustment for wear, the frictional points of the bar E being very small, as shown in the cross section drawing, and the large back jilate having adjustment screws so that the fitting may be altered as required. The rate of movement of a fine adjustment of this descrip- tion would necessarily vary with the size of the limb of the microscope, but the average rate of movement per turn of the milled head is 'Oo m/m. The S]iecial virtues claimed for this fine adjustment are extraordinary strength of construction, enabling it to stand rough treatment, and extreme sensitiveness. There is every indication that these claims are fully justified. NOTES AND QUERIES. J. /•'. A. — I have heard it stated that the blood of an habitual drunkard is different in appearance microscopically to normal blool. Can you tell me if this is correct, and if so, in what way it differs '? If any reader can obtain a drop of blood from such a subject and spread it on a microscope slip or cover glass, this question could no doubt be settled, but I am not aware of the existence of a difference. T. H. .V. — Of the micro.scopes you name, the D.P.H. Xo. 1 by Baker is unquestionably to be preferred. It is well designed and soundly constructed. »b'. P. — Light filters are a necessity for photo-micrography of coloured objects. You cannot get satisfactory contrast without them. Of solutions, acetate of copper or Gifford's screen are the best, but opticians sell coloured glasses which usually serve the purpose. If these are used close to the lamp flame, they should be optically worked, any defect in the glass being present in the field of view when the condenser is focussed. If the coloured glass be placed immediately beneath the condenser, the optical working is not a necessity. The latter position is equally as good as the former. Communications and enquiries nn Microscopical matters are cordially inrited, and should be addressed to M. I. Oros.s, Kxowi.EDfiE Office, 326, Hif/h Holhorn, W.C. NOTES ON COMETS AND METEORS. By W. F. Denning, f.r.a.s. C'oMKT A 1901. — A considerable number of observations of tliis object have been published in the Astronomische Nachrichlen and other journals. The proximity of tlie comet to the sun must liavc rendered it difficiilt to detcnnine positions accui'atclj, but tliere is httle doubt tliat the orbit will be satisfactorily obtained. The comet was observed at various stations in Soutli Africa and Australia, it was also seen at Trinidad and at ilount Hamiltim, California. But the conditions of its appearance were such that it came under notice at very few northern observatories. lu fact, after perilicliuiet spiTf I'iso t» iimiiy I'lmfliitiiii; statoironts, Imt the hoiic was iiuoiir!>!;i'typli> «i'ii' diiia|>|u'intoil in faihng lo lalih a ^liinpso of it, but it nia\ bo sonu- uonsohil ion tn Iheni to know that a naktHl-ovi" ooniet boi-t>inos visible nearly every year, anil that they will )ir>>bably not have lon^ to wait hefi're viewini; one of these wonderliil anil mysterious visitors. DisTRiui'Tiox OF CoMETART Peiuiikli.\.— With refpxrd to the eomets of short period, belonjjiiit; to the Jovian family, of whieh there are now about 32 known with more or less eertainty and probably quite distinct biMlies (though less than halt of them have been observed at moiv than one return), it is remarkable that the lonsitiide of perihelion falls between UDO — JUiO' and 0-60 in 20 eases, whereas It is found between tJO'— ;!00 in only 12 eases. In other words, while 120 of longitude elaim 20 eoniet", 210 elaini only 12. Were the distribution perfectly equable the proportionate nnndiers instead of beins; 20 to 12 woulil be 10,"7 to 21.'!. The dense grouping therefore between 30(P — 360 and 0' — GO is signilieanl that some speei.al cause has operated in arranging these eonietary perihelia on one and the same side of the sun. In this eonneition it is also interesting to note that the number of meteors encoiuitered by the earth in passing from longitude 27l>''-36(V and ()»— 90^ is about ilmible that met with in moving from 9l>° — 270", anil a partial explanation may be found in the special aceiunidation of cometary jiaths on that side of the sun near the first point of .\ries VThere the earth would be hkely to pick up more fragments than on the opposite side in a region traversal by comparatively few eon.ets. This grouping does not, however, appear to be true of parabolic eomets, ai'-ording to some deductions by Chambers in his Descriptive Astronunii/, but the subject is of sulheient importance to be in\ estigated on the basis of all the materials obtained up to the present time. Though only 32 Jovian comets (including the rertain and doubtfcd instances) are known, it is likely that an\ |>cculiaritv affecting the distribution of these also affects the whole class, which probably numbers siuue hundreds at least, fur in spite of the perseverance and success of comet seekers during the past century, it is certain that a great many short period comets have managed to evade discovery. Large Meteors. — In the spring and early summer seasons there is little to offer special attractions to meteoric observers apart from the April Lyrids and May Aquarids. But there are a considerable number of minor showers visible in various parts of the fh-mament, and brilliant fireballs are occasionally recorded. A few bright meteors were obsei-ved in May. 1901, and the following are some particulars : — May 11, 14h. 2m. Equal to Sirius. Passed from one-tliird the distance from ^ to ? Draconis to Tj Cephei. Prof. A. S. Herachel, Slongli. May 11, Uh. 27Jm. Equal to Vega. Path, 270° - 10" to 28.5" -10°. Duration 3 seconds. W. H. Mordoch, Glasgow. May U, llh. 3m. Equal to Vega. Path, 12.5 + 30 to 148 + 12. Duration 7 seconds. Prof. Herschel, Slough. Mav 15, 9h. 3m. Terv large, and estimated ten times more brillia"nt than Tenus. FeU from altitude 60° due N. to 30° N.W. T). R. Springall. Norwich. May 15, lOli. Om. Brilliant meteor of a green hue, and leaving a tail of red sparks. ])as3ed vertically down S. by W. sky, near horizon. Miss L. M. Milncr, Torquay. May 10, between llh. and llh. 15m. Large meteor about twice the size of Mars passed from near a Hcrculis througli northern part of Cepheus and disappeared just under the Polar Star. It moved very slowly. W. H. Venables, Tripoli, Barhary. May 17, 12h. 25m. Brighter than Jupiter. Travelled from the head of Serpens to N.^., ending between a and >; Boiitis. Dr. 1'. Xoble, Radfield-by-Sittingboume. JrLT jrBTEOBS.- With July we have the advent of the most ii.teresting part of the meteoric season. .Alter the middle of the month shooting stars become numerous, and towards the end there are many .Vquarids and Perseids. This year obsei-vations will be best made in the com]>arative absence of moonlight between the lOth and 27th, though even at the close of the month and early in August thi*re will be plenty of meteors to record in spite of the presence of OUT satellite. It will be important to watch for the earliest manifesta- tion of the Perseids at about the middle of July, and to deteriuinc the position of the radiant on any and ivcry night wiien a sulRcieiit number of path- have been registered to indicate it satisfactoril\. THE FACE OF THE SKY FOR JULY. By A. Fowler, f.r.a.s. The Scn.— On the 1st tbe sun rises at 3.48, sets at 8.18 ; on th; alst he ris«js at 4.23, and at 7.40. Ho is at his £;fpatost dislaiu'c from the oai'tli oil thf 41h at ."i r.M., his ajiiiaiont ilianii'lor then rouchiiiL;- its iiiiniinaiii vahi(> oafaiict' i.i a larui' s|Hil (hiring tho Uittof liall" of May sio^u-osts that tho sun h;is eiitofed on a new period of spot activity. The Moon. — The moon will be ftdl on the 1st at 11.18 P.M., will enter last qiiartt^r (0 The Second Series of Lines in the Spectrum of Hydrogen. ^\ Ep-n-ARn C. PicKERiyo isl Letter : Lr.vAE Atmosphere and 0( bans. By J. O'May ... 1S2 British Ornithological Notes. Conducted by Harht F. WiTHEEBT, F.Z.S., M.B.o.r " 1H2 Notices of Books 183 Books Received 185 Notes ISo Men and Microbes. By E. STBXHorsE, a.r c.s., B.st. ... 187 Microscopy. Conducted by 51. T. Cross ... ISH Notes on Comets and Meteors. Bv W. F. Denning, F.K.A.S " 190 The Face of the Sky for August. By A. Fowler, f.e.a.s. 191 Chess Column. By C. D.Locock, b.a 190 FLOWERING PLANTS, AS ILLUSTRATED BY BRITISH WILD-FLOWERS By K. Lloyd Praeger, b.a. IV.— FLOWERS AND FRUITS. Some of the leading characteristics of those all-imjiortaiit parts of plants which we call flowers wei'e touched on in my last article, and the uses and more striking variations in shape and colour of the individual blossom were briefly dealt with. From the individual flower we may pass on to the consideration of infloi-escences, or groups of flowers considered as a whole. Most of the wind-fertilized plants have their flowers arranged in more or less elaborate inflorescences — the beautiful com- pound panicles of many grasses furnish examples, and the dense flower-spikes of the Reed-mace and the sedges. In these cases, as already pointed out, the most advantageous position for the flowers to occupy is the apex of the stem, where they will receive the greatest amount of air and light, hence the minute flowers of plants such as the above-named are crowded together, often in enormous numbers, at the top of the upright stems. In insert-fertilized flowers, where conspicuous- 11CSS is a desideratum, development has proceeded in two directions, and showincss may be ihio either to the great eiil.ugenieiit and coloration of parts of tlie individual flower, or to the grouping in a dense inflorescence of immeroiis smaller flowers — and, of course, all kinds of combinations of these conditions occur. Tn most of the plants in which the fonner extreme prevails, the flowers are solitai-y ; the single blossom is sutliciently con- spicuous to attract the attention of insects. Tn the second photograph in my last article, the contrast between these two methods of " advertising " is clearly shown. Many instructive examples of the giouping of blossoms are to be found among our familiar wild flowers. Our commonest Orchids, such as belong to the genera Orchh, Hahennrin, and Lixterii, have their blossoms arranged in a dense >ct produced by the gi'oupin;; of uuiiiermis small ilowevs. When flowering is over, and by means of insects or the wind or other agencies fertilization ha.s been effected, thci-c follows a period unintc>resting to the casual observe)-, but of the greatest importance to the plants — the period of tlie growth and development of the fruit — that is, of the seed and its envelopes. In many cases, beyond the falling off or witheriiig of the no longer useful showy parts of the flower, no external change is noticeable ; but in many plants this is a period of vigorous growth — as in the Peas and Beans and many Cruciferous plants, and in plants with fleshy fruits, such as the Apple and Plum. The corolla, when its work of advertisement is done, usually falls ; sometimes, as in our common Heaths, it remains di-y and withered, and no doubt serves to protect the ripening fruit. The outer whorl, or calyx, is more persistent, and very frequently wi-aps about the young fruit, often growing as it grows, ?nd forming a protective envelope. In many plants interesting movements may be noted between the periods of flowering and fruiting. In the numerous Pondweeds, for instance, which grow submerged or floating in wat«r, the flowers are wind-fertilized, and during the period of blossoming the spikes of flower stand up erect above the water owing to curving of the flower-stem. When flower- ing is over, a reverse ciu-vature submerges them, and the fruit is ripened below the surface, where it is less liable to misadventure from wind and wave. In the Water- Crowfoots, which are insect.-fertilized, tlie same move- ment may be observed. A reverse movement is notice- able in various insect^fertilized land flowers. The buds of the Wild Hyacinth, Columbine, St. Dabeoc's Heath, are erect, but on expanding the bell-like flowers hang mouth downward, thus protecting the delicate essential organs from rain and cold. W^lien flowering is over, the erect attitude is resumed, and the fruit ripens in that position. The Meadow Crane's-bill and Wood Crane's- bill are closely allied species, and much resemble each other in general appearance ; but while the fruit of the one stands erect, in the other each fruit is pointed down- ward. What subtle difference between the mode of life or surroundings of the two plants has produced this change of posture since their derivation from a common ancestor, it is not easy to conjecture. And now, as the result of this long life-histoiy, the seed lies mature and ripe within the seed vessel — be it a leathery pod, or a woody box, or a juicy berry or pome ; and the seed vessel is ready to separate from the parent stem, or to open and allow the seeds to escape. This is a critical time in the plant's history ; quite as important as the period of flowering. On the successful sowing of the precious seed depends the life of the succeeding generation. What wonder then if we find, in connection with seed-dispersal, ai-rangements as elaborate and contrivances as ingenious as those which we have glanced at in connection with flower-fertilization. In comparatively few cases do the seeds merely fall to the ground beside the parent plant, with apparently no means of further dispersal : the Buttercups and Wood Anemone appear to Iseloug to this category. More frequently advantage is taken of some motive agent, which can assist the seed to a wider dissemination, that it may grow up clear of the impending shade of the parent, and of the exhausted soil which surrounds it, and by seeking fresh woods and pastures new, colonize the country and hold its own in the rough-and-tumble of overcrowded vegetation. These motive agencies are furnished by wind and water — notably by the former — and by animals. The simplest cases of wind-dispersal we see in the swaying of the herbs and trees as the breeze rustles through the woods and meadows. In many plants the ripe fruit or seeds lie in cup-shaped or saucer-shaped receptacles, out of which they would Algist, 1901.] KNOWLEDGE. 171 not in calm air fall until the docay of the seed-vessel or the stem allowed the escape of the contents. The saucer-shaped recept^ieles of many of the <'oiii/i(i ^ Fig. 1 — Building a Square Brick Hut. Tlie bricks in the foreground are baking in the sun. the use of the steamers. Notwithstanding the scarcity of timber near Khartoum, and the fact that no other fuel is available, the gangs of natives employed to chop this wood were not then under sufficient supervision. The consequence was that much wood had been wasted and many fine trees ruthlessly maimed. We often passed a mile or two of stumps four or five feet high left in the ground, " and so many of the best trees had been mercilessly lopped by the careless and ignorant natives, that near these wood stations it was often impossible to find shade for our tents. I was assured, however, at Omdurman. that the method of cutting the timber would shortly be improved. The mimosa bushes, which form the dense under- gro%vth, are thickly covered with thorns of three to five inches in length, exceedingly sharp and strong, and of a dazzling white as though they were enamelled. As we ran short of pins we found these thorns exceed- ingly useful in packing our bird skins, but they made the country difficult to '" negotiate." One was driven through my boot into the foot, another .pierced the leg of one of my companions, and a third completely lamed a donkey for a month. The acacia trees, too, are plentifully provided with smaller but no less annoying thorns, and there are but two varieties of bushes with- out them. Perhaps I have not drawn a very enchanting pictm-e of the country it was ovu* good fortune to work in, yet, notwithstanding its undoubtedly monotonous character and the lack of the pleasing colours and sun effects of Egypt, there is a peculiar fascination about this country near Khartoum. Its very extent and barrenness are a charm and confer an exalted idea of freedom on the traveller, while the scarcity of cover causes the naturalist to search through what little there is with an exaggerated delight and keenness. The natives of these parts rarely lived under the trees. Every village of any importance was situated on the bare desert with no protection from the burning sun or scorching wind. In the vicinity of the villages there were always to be found large patches of ground used as cemeteries. The graves were the slightest mounds, having a stone, or a stick with a piece of white cloth tied to it, planted at either end, while a number of broken pitchers were placed bottom upwards here and there amongst the graves. The huts composing the larger villages were usually round in shape with conical straw roofs, the walls being built with bricks, which are burnt, only by the heat of the sun. Some were square with Hat roofs built in the same way as the majority of those in Omduiinan, while a few had a i"ough verandah in front. All along our route, however, there was a great number of people living in veiy small huts which could be " stnick ' and moved about almost as easily as tents. These huts varied in shape and in the material with which they were constructed. Some were round with conical roofs and were entirely made of " dhura " straw, while a few were dome-shaped. The majority, however, were oblong, measuring about 6 feet broad and 7 or 8 feet long. These were not more than 5 feet l.igh, and had flat roofs usually made of straw or matting, but sometimes of fo^dder, so that more than I nee a native sold us half his roof as food for our camels, ^traw, cane matting, or cloth was used indiscriminately lor the walls. The rough cloth used for this purpose is made of a mixture of goats' hair and sheep's wool, which is spun by the women on to a rough spindle in the same way that they spin cotton. A primitive loom is made on the ground with poles held in position by pegs driven into the sand, and the women while weaving squ.at down under a temporary sun-shelter. These movable dwellings were sometimes placed under trees, FiO. 2. — A Dome-shaped liut witli a " Veranduli." ]lie hut i.s made of matting and i-loth, but generally in the open, and there were seldom more than six or eight together. The natives inhabiting them were very shy, and twice when we pitched our tents near an encampment the people were soon busy 176 KNOWLEDGE. [August, 1901. rolling up the matting and cloth forming the walls of the huts, and in a few hours disappeared, cari7iiig away their roofs by the four comer poles, their rolled-up walls, and all their goods and chattels. V\'hen asked why they moved away from us they gave no rea.son beyond remarking that they objected to our tents being near them. lu two or three places we found natives living in a much rougher sort of hut, built under very thick bushes which had been cut out in the middle and thickened on the outside, thus forming natural " Zareebas. ' The reason for such diversity in dwellings lies in the mixed chai-acter of the population of this stretch of country. Arabs and blacks of many tribes inhabit it. and although rather thinly populated, the people were so evenly distributed along our route that we were bcarcely ever out of sight of a native. At the time of our visit the men were enjoying idleness, but the women were always hard at work carrying water or grinding corn. The corn is placed upon a wide and heavy stone and is then gi'ouiid with a smaller stone, which is rubbed and rolled backwards and forwards. The stones wear away rapidly, and a family must actually consume a goodly number in a lifetime. The boys are also kept busy shepherding the goats and sheep, which are in thousands all over the country. These animals are very rarely slaughtered and are kept merely for their milk. In the wet season, of course, conditions are eutirel}' changed, and the men are busily employed growing " dhura," maize, cotton and other produce. At the end of the dry season food becomes so scarce that the goats are fed upon the roots of the grass, the grass being hoed up, and the roots beaten soft with siioi-t wooden clubs. Near the large villages we found the natives decidedly independent and difficult to get on with. In the smaller villages and isolated communities the dress, or rather the greater want of dress, at once showed the people to be of a more uusophisticated nature. They greeted us with many salaams and much kissing of Fig. 3.~A .Vitiif loum. hands, and were more willing to give us such supplies as they could, but very little work could be got out of them. At every camp we harangued the " Sheikh of the nearest village and asked him to procure us animals for our collection, but wc stipulated that they should be brought in alive and uninjured. Wc offered varying rewards, but at only one camp did the natives shov.- any interest or take any trouble to earn the reward. At this camp, near a rocky hill named Gebel Auli, the natives brought us a number of bats and some rather rai'e hedgehogs, caught in the caverns on the hill. The bats were brought by a boy who appeared with his shirt bulging out and held up to his neck. Out of the shirt were extricated, amidst considerable amusement and excitement, half-a-dozen live bats with long and very sharp teeth, which were more than once used with great effect. The bats were swarming in the cracks and cavenis of Gsbel Auli, and their squeaking could be heard at a considerable distance. The natives poked long sticks into the cracks and out flew the bats, which YiG. 4.— A Movable Hut made of Hatting. Tlie woman ou tlie left is grinding corn, while the two seated on the " angarib," or nati^■e bedstead, are spinning. were knocked down with cloths. The hedgehogs which were brought to us from this same hill were exceedingly pretty little beasts with dark spines and whit* hair. On them we discovered some elegant yellow fleas, which I gave to Mr. Charles Rothschild, who collects these parasites. He proclaims them a new species, and has done me the honour of naming them Pu/ex Witherbii ! Ill general, however, the offer of a reward for animals would produce great keenness among the natives for only a day or so. They would bring in any number of the common rats of the country and. although we stipulated for live animals, every bone, skull, or bit of skin that could be found would be brought in the hope of reward. But when they found that we needed no more of the rats that swarmed in their hvits, these very lazy natives returned to their normal occupation of sleeping and eating and refused to hunt any fiu'ther. This seems extraordinai'y, because luxuries to a certain extent can now be bought for money m the markets of all the larger villages through which we jsassed. In the days of the Khalifa it was rather a disad- vantage for a man to become prosperous. The tyrant would soon hear of it, sweep down upon him and carry off his flocks and corn. As several natives said to us when we asked them why they refused the money we offered for goats' milk : " The Khalifa never took the milk, he always took the goats unless thev w-ere driven away and hidden. Now you come and onlj' w'ant the milk and offer to pay for that ! " No doubt they think the English fools. Although singularly uniuquisitive the natives pro- vided one of the trials of collecting by their ubiquity. One could never be sure on shooting at a bird v/hether Ai'orsT, 1901.] KNOWLEDGE. 177 a concealed native would uot rise fi"oni behind a bush in the line of tire at the monieut. We never actually shot anyone, however, although there were many narrow shaves. The traps which we set for mammals, although carefully concealed, seldom brought us profit. Goats tramped over them, natives stole them, presumably for the copper wire of which they wore made, and dogs dragged them away for the meat with which they were baited. These dogs, as is usual in Africa and the East, are never fed. and consequcntlv become very bold and expert thieves. I had tJie misfortune to be ill in our first campi, and the dogs used to creep into my tent at night and drink the milk at my bey .J. E. Gore, k.k.a.s. It is probably a matter of common observation that on a clear moonless night it is never absolvitely dark, even at midnight; a certain amount of light is given by the stars. W^hat does this light amount to in terms say of full moonlight; Miss Gierke, in her "System of the Stars, " gives the light of all stars down to 9\ magnitude as about l-80th of full moonlight. M. G. I'llcrmite found starlight equal to 1-lOth of moonlight, but this estimate is evidently too high. The difTercnce^ between a bright moonlight night and one illuiuiiiatcd by star- light alone is very considerable. Let us make an attempt to estimate the total amount of stai-light by computing the light emitted by all the visible stars down to the faintest point visible in the largest telescopes, like those of the Yerkes and Lick Observatories. The data available for this calculation are rather uncertain, but an approximation to the truth may perhaps be possible. To express the total amount of starlight in terms of the light of a star of zero magnitude, like Arcturus, and thence in terms of moonlight, let us assume — as is now admitted by most authorities on the subject — that the total number of the visible stars is about 100 millions. Let us also assume that the " light ratio " is 2.512 (now accepted by all astronomers) — that is, that a star of zero magnitude gives 2.512 times the light of a star of the 1st magnitude, a star of the 1st magnitude 2.512 times the liglit of a 2nd magnitude star, and so on. To enable us to make this calculation it will be necessary to estimate the number of stars of each mag- nitude down to the 17th magnitude, which is about the faintest visible in the great Yerkes telescope. Dr. Gould, in his I'riiiiiiiiietrKi Arijiniiiia, gives the following formula for computing the total number of stars visible in both hemispheres to any given magnitude, m. 2,„ = 10051 X (3-9120)'" From this I find the following : MufJHU' inle. To ].0 iiiflusiv<^ „ ^•" „ 3.U „ ., 4.0 „ .5.0 „ 6.0 „ 7.0 ., „ 8 0 „ 9-0 „ , From this it will be seen that the formula gives for. the fainter stars numbers enormously too large. For the brighter stars, viz., those of the 6th ^magnitude, the numbers seem to be rather small. liouzeau, who ob- served himself all the stars visible to the naked eye in both hemispheres, gives the following figures: — MiiL'iii tilde. No. ofStiirs. 1 20 2 51 3 200 4 ... 595 5 ... 1213 6 . . ... 3640 No. of Stai'.s. Magnitude. No. of Stnrs. 3-93 To 10.0 inclusive 843,718 15-74 „ 11.0 3,283,870 6017 „ 12.0 12,!11 1,448 235-4 „ 13.0 50,511,000 920-9 „ 1-t-o 197,602,545 3GO'Z-5 „ is-o 773,021,071 14,093 „ 16.0 3,024,057,632 .-)5,131 „ 17.0 11,8.30,114,720 215,674 Total 5719 178 KNOWLEDGE. [AuousT, 1901. Accepting those figm-es, and adjusting the remaining magnitudes to suit a total of 100 millions down to the 17th magnitude, we obtain the following table: — MagnitTide. Sirius aud Canopus. Aroturus. Oipella, Vi'gi, a Centauri, Rigi'l and Procvou. To this magnitude, fiV, tlic numbers of the stars in each class have been assumed from Houzeau's results. Thenum- bersinthe fainter magnitudes have then been rough- ly adjusted so as to mate the total about 100 millions. This may seem a rather arbitrary pro- ceeding, but there is evidence to show that the stars really "thin out " below the 11th magnitude. It will be noticed that the numbers in column 4 of the above table rapidly diminish for the fainter magni- tudes. If there were 100 millions of stars of the 20th magnitude their combined light would be only equal to that of a single star like Arctiu'us. From this it is cleai' that the light of all the stars below the 17th magnitude may be safely neglected. In addition to the stars there are a large number of nebulse scattered over the surface of the heavens, but the majority of these are such faint objects that their com- bined light must be inconsiderable. Assuming a total number of 120,000 nebulfe and an average brightness for each equal to that of a star of the 8tli magnitude. we have their combined light equal to 30 stai-s of zero magnitude. Hence the tot-al light of all the staxs and nebulae in both hemispheres would be equivalent to that of 589 stars of zero magnitude like Aixtui-us. This estimate, of course, includes the Milky Wav. Now to find what fraction this is of moonlight we must consider some estimates w-hich have been made of sunlight and moonlight. Huygens in the 17th centtuy found the sun 7.56,000,000 times brighter than Sirius; Michcll in 1767 found 9,216,000,000; Wollaston in 1825-6, 20,000,000,000; Von Steinheil in 1836, light of Sirius. 3,840,000,000; G. P. Bond in 1861, 5,970,500,000; and A. Clark found 3,600,000.000. The mean of all these rather discordant measures is: — Sun's light = 7,230.000,000 times Modern photometric measures make Sirivis about four times the brightness of Arcturus. and hence we have Sun's light =28,920,000,000 times light of zero star. Comparing sunlight with moonlight. Bouguer found the sun 300.000 times the brightness of full moonlight: Euler found 374.000; Wollaston 801,072; G. P. Bond 170,980. and Zbllner 618,000. The mean of these is 512,810, but ZoUner's estimate of 618,000 is the one now generally accepted. Assuming this value, we have- Moonlight = 28.920,000,000 618,000 Moonlight = 46,800 times light of star of zero magui- tude. Hence starlight =-'''— = — of moonlight. ^ 46,800 80 ° This result gives for one hemisphere (which is all that is visible from one place at one time) Starlight = — -- of moonlight, "^ loO And this is probably not far from the truth. An examination of the table will show that the com- bined light of the stars below 6h magnitude is con- siderably greater than the light of those above that magnitude, so that if all the stars visible to the naked eye were extinguished we should still have nearly the same amount of starlight. CONSTELLATION STUDIES: By E. Walter Maunder, f.r.a.s. VIII.— THE ARCHER AND THE WATER- BEARER. The constellation of Sagittarius, when on the meridian, is almost entirely above our English horizon, but it lies so low that it is perhaps less familiar to us than any other of the zodiacal signs, for though Scorpio does indeed lie lower still, its brilliance has made it better known. Still, there is no difficulty in recognizing it on a very clear night, at its culmination, which takes place at midnight at the end of June. The old rhymester directs us — - " From Deneb, in the stately .Swan, describe a line south-west Through bright Altairin Aquila, 'twill strike the Archer's breast." Or, most strictly speaking, his shoulder, marked by the bright star, Sigma. A little in advance of Sigma are five bright stars in an undulating line on the east-em branch of the Milky Way. which here sufTers one of its numerous divisions. Proceeding from the most northerly of these downwards, they are lettered Mu, Lambda, Delta, Epsilon, Eta, and mark the position of the Archer's Bow. A pair of stars, both bearing the letter Gamm.a, a little in advance of Delta, marks the point of the Arrow which the Archer is discharging at the Scorpion, whilst Zeta, a bright stai- a little below Sigma, marks the wing of the Arrow. A little triangle of stars, Xi, Omicron. Pi. mark the neck of the figure, and practically exhaust the list of its brighter stars. Alpha and Beta, the latter a wide double star to the eye, are in one of the hind legs of the Man-horse, but are below oiu- English horizon. But though Sagittarius is not. a distinguished constel- lation, viewed as a whole, it is very rich in objects of the gi-eatest interest in opera-glass or telescope. Mu, the upper horn of the Bow, is the centre of a region AurtrsT, 1901.] KNOWLEDGE 17U as rich in star clusters as the nebulous region in Virgo is in nebulie. A wonderful object, number 8 in Messier "s catalogue, foi-nis a rhomboid with Mu, Lambda and Delta. North of Mu lies number 24 of the same cata- logue, a st.ar cluster quite unlike Messier 8, but almost as attractive. Passing upwards in the same straight line, we come to Messier IS, then ^Icssier 17, the famous ■ horse-shoe " nebula, and a little further off, Messier 16. These dustei-s are the principal objects in the little modern constellation. Scutum Soljieski, a little asterism which Heveliiis devised to celebrate the valiant John Sobieski, king of Poland, and deliverer of Europe from the Turk. Proctor and Some other modern map makers omit the const^^llation entirclv, and for the sake- of sim- plicity it is well that it should be so. As designed, it filled a small triangular space between Serpens, Aquila and S.igittarius. It was practically entirely enclosed The constellation lies below our English horizon, with very little to mark it from any point.. The next zodiacal constellation to Sagittarius is Capricornus, small and easily found. Just as Sagittarius is a centaur or man-horse, so Capricornus is almost invariably a goat-fish. The goat has usually been ex- plained as signifying the sun at the winter solstice, seeing that after that season has passed, the sun begins again to move upward in the sky; the rock-haunting goat or ibex being adopted as the symbol of the climbing motion of the sun, whilst the fishtail pointed to the rains and floods of midwinter. We know, however, that tho consternations were mapped out many centuries before the winter solstice fell in Capricorn, and that the explanation, howevei- iiinenious, was but a. Inte guess, made when ail actual recollection of the iiieaiiing of the sign had been lost. XXIV XXlll XXII XXI XX XIX ;^:-&&i''' "~'\^ „.•>• AQUILLA -e > *''^^n3t~J!! '"/SERPENS ^^^^^^^^^^ "i^^^^^^'^'^'^^asiljSB^ •■'' '' ^*^ ° AQUARIUS ^ ^^*^^^*=3Ha=: CETUS ^ J^o . "■ ^^^'^'''''^''^V*,^ •' ^■- 3 •2 ' • . ■ CAPRICORNUS •ff«5t„^ ^;:f^_ _ J : •75 \ « u 47 ^ . • ^'szto*. ■'■#;.■;■■■. \^^ •ft \ \ 9" \ 4. f .^^N 1 ■; ^- -.._. % Xs^ •■• , ■ .# ■ \ i ' , ,, PISCIS / ---.^ , .^Ni^j^o*^ #■■> l..-—-.^ /JBFomilKaur .9 '■• ' 41 *1 ^*^^^ * /■ .•'■■' \ '^ ' 'I" \ y .„ ^ •- •ff'^ * / i <*, -^ ^ H J" " ./^ \Microscopium; sagitarius .t;^' 'N \* \ 'q\\ 'V GRUS ^ /8 V' ■ > SCULPTOR >V^" 'e *^ ^-..^'i.-'y.^ •• •- V .,.COROLLA'^V"'«5S7 ^ %. v.. •< '. T«, -■' -^.j/y ••>" •» • ,„ V / "*--■/ INDUS ' " V TELESCOPIUM S?"'^^. •/ .cx'?^'^^ ."•■ PHCENIX ' ' ^.X TOUCAN [;. ; •„ .^ I XXIV XXlll XXII XXI XX XIX XVIII .Star Map \o. 8; Tho Region of the An-lu-r ;ind the Water-liearer. XVII within the borders of the Galaxy, and contains but a single notable star, the variable R. Scuti ; but its wealth of telescopic stars, clusters and nebula' is most remark- able. Sir William Herschel estimated that in live square degi'ees of space it contained one-third of a million of stars. Of its clusters the most wonderful is just visible to the naked eye, and is Messier 11, the " Flight of W ild Ducks," on the north-east«rn border of the constellation. The fore-feet of Sagittarius are oft«n not shown in the designs of this constellation, the place where they should come being occupied by the Southern Crown. " Other few, Below the Archer, under his fore-feet, Letl round in circle, roll without a name." (Prown'^^ Araftis.) Capricorn may bo found by diawing a straight line from Vega through Altair. Omega Capricorn! lies just as far below Altair as Vega lies above it, and marks one knee of the kneeling goat. Psi, immediately above, lies almost on the straight line from Altair, and Alpha and Beta, wliich mark the root of the horns and the eye of the animal, are but little in advance of the line, only considerably higher up. Alpha is Algedi, which simply means "the goat"; Beta is Dabih, "the slaughterer." The first of these stars is a visual double, and it is interesting to note that it has become so com- paratively recently. The two stars have no real con- nection with each other, and their proper motion is carrying them apart by something more than a minute 180 KNOWLEDGE. [August, 1901. of arc in a thousand years. Beta Capricorni is also a beailtiful double in the opera-glass, the fainter star being of a sky-blue tint. The only other stars of any gi-eat brightness in the constellation are Zeta, Gamma and Delta, which mark the fishtail. Delta is indeed the brightest star in the whole asterisni, and bears the name Deneb Algiedi, the " tail of the goat." Following Zeta by about the same distance that Alpha is from Beta, the opera-glass will show as a faint point of light 30 Messier, a large cluster of remarkable richness. " Down from bright Vega, cast your gliince across the Dolphin's space Then just as far again you'll "find the Waterbearer's place." Aquarius is one of the straggling constellations, and pretty ncaxly overwhelms Capricornus. He has been figured from time immemorial as a man pouring out a stream of water from a pitcher ; but for some reason, which is now lost to us, his right arm is stretched back- wards to the fullest extent possible so as to reach over almost the entire length 8f Capricorn. The figure is by no means clearly marked out in the main. The stream from the pitcher can be traced in the number of faint LVNX / URSA •• * MAJOR • CANES ^^ CAMELOPAROUS PER5EUSJ&1 " URSA MINOR ,i«^ * HERCULES • , >^ PISCES ' • «";"^. ^^^''' *" ' . i *• The Midniglit Sky for London, 1901, August 5. stars in the eastern portion of the constellation, which lead downward in wavering curves to Fomalhaut, a star of the first magnitude and one of the four ancient Royal Stars. Dwellers further south can recognize Fomalhaut without any difiiculty, since Achernar lies just mid-way between it and Canopus. But at 2 o'clock in the morn- ing in the present time of the year it is impossible for English obseivers to mistake the star; it lies low ctown on our southern horizon without any serious comj)etitor near it. Its name Fomalhaut simply means " the Fish's Mouth," for strangely enougii through all the long centuries that the starry symbols have come down to us, Aquarius has always been shown as pouring forth his stream of water into the mouth of a fish ; soirely the strangest and most bizarre of symbols. Fomalhaut, Beta Capricorni and Alpha Aquarii form the points of a triangle which is nearly equilateral. Alpha Aquarii is known as Sadalinclik, the " fortunate star of the King "; Beta Aquarii, one-third of the way from Alpha Aquai-ii to Beta Capricorni, is Sadal Sud, " the luckiest of the lucky," supposed to refer to the good- fortune attending the passing of winter. Alpha and Beta mark the two shouldei-s of the waterpourer, and three bright stars near Alpha, Gamma, Eta and Pi, with a fourth, Zeta, almost in the centre of the triangle, mark the body of the pitcher from which Aquarius is pouring. The outstretched arm of Aquarius is marked by a slightly curved line of stars extending from Beta Aquarii to Alpha Capricorni. Two fairly bright stars, Mu and Epsilon, near Alpha Capricorni, give the place of the Waterbearer's hand. In the middle of the arm is Nu, a much fainter star, and about a degree and a half preceding it. Just barely within the power of an opera^glass to reveal it as a faint point of light, is one of the most wonderful of the planetary nebulae. Mid- way between Alpha and Beta Aquarii, but above the line joining them, is M. 2, in the head of the Water- pourer; "a heap of fine sand" where each grain is a sun. Those who have the opportunity of observing from southern or ecjuatorial regions, will find the brightest and most easily recognized of all the new constellations due to Dircksz Keyser, just south of Piscis Australis, the constellation of which Fomalhaut is the chief star. This is Grus, the Crane, and five bright stars distributed at equal distances along a gentle and regular curve, whilst a bright second magnitude star precedes them, form its principal characteristics. The Microscope, interpolated by Lacaille between Sagittarius and Piscis Australis, and the Sculptor's Tools, now more generally known as the Sculptor, which ho added below Aquarius, are as destitute of features of interest as the designs are of appropriateness to their celestial svu-roundings. PHOTOGRAPHS OF THE NEBULAE W V. 32 ORIONIS, y IV. 2 MONOCEROTIS, Ijl IV. 28 CORVI, AND y I. 139 (M. 61) VIRGINIS. By Isaac Roberts, d.sc, p.e.s. NEBULA y V. 32 ORIONIS. R.A. 5h. Im. 57s. Decl. 3° 29'-4 South. Epoch 1900. Scale— one millimetre to twelve seconds of arc. Repeeences. N.G.C. 1788. G.C. 1005. h 347. y V. .32. Rosse, Ohs. Neh. and Gl, p. 46. The photograpli was taken with the 20-inch reflector on February 28th, 1890, between sidereal time 5h. 44m. and Sh. 4ni., with an exposure of the plate during two hours and twenty minutes, and it shows the nebula to be cloud- like in form and extending in north preceding to south following direction with fainter nebulous extensions towards the north following. There are dark areas which indicate that we can see, through gaps in the nebulosity, into the lightless void beyond it ; the larger gap being on the south and south preceding sides, with a solitary faint nebulous star-like condensation near its centre. One star of about 9th magnitude with a comes of 13-14 magnitude are apparently involved in the northern part of the nebula, and in the south foUou'ing end is an apparently nebulous star of about 10-11 magnitude; there are also seven or eight stars of less brightness than 13th magni- tude contiguous to the nebulositv ; some of them are :d W z Pu O a: < o o H O 3: (/J '5 'So u o U 00 Auoi-sT. 1901. KNOWLEDGE 181 involved in it. The brighter stars niiiy not bo involved in the nebula but seen in alignment with it. There is no indication that the nebula has great di>pth, but rather that it resembles a relatively thin cloud which can p.utlv 1)0 seen through, and the" two bright stars apparently involved in it have projections of nebulous matter extending from them which somewhat resemble the projection from the star Ehctra in the PJ,uuI,g. In order to see these appearances clearly it is necessary to examine the origiuiil negative, for they are too faint to be reproduced ou paper prints. NEBULA Ijl IV. 2 MONOCEROTIS. R.A. 6h. 33m. 42s. Decl. 8° 49'-3 North. Epoch 1900. Scale — one millimetre to twelve seconds of arc. References. X.G.C. 2261. G.C. 1437. h 399. y IV. 2. Rosse, Ohs. of Neb. and CI. of Staff, p. .53. Phil. Trans.. 1833, PI. XIV., Fii,'. t)4, and 1850, PI. XXXVII. Pig. 10. Lassell, Mem. li.A.S., Vol. XXIII., PL IL, Pig. 8. The photograph was taken with the 20-inch reflector on January 2~tb, 1900, between sidereal time 3h. 43m. and 5h. 13m., with an exposure of the plate during uiuety minutes, and it shows the nebula to be in form like a fan, or comet, with a star of about 11th magnitude at the apex. There is faint nebulosity with structural characteristics ou the north preceding side, and an extension, like a streamer, on the north followimj side. The nebula resembles the two that are near Gamma Ca^.'siopeia (Y>nh. in Knowledge, Mav, 1898; and in I.B Pho. ofNeb.and Cl.of Sfars,Yo\. II., PI.' XXV.). It also reseuibles the nebula IJ. I. 143 Virginig. Two or three condensations are visilile in the nebulosity. In the Phil. Trans., 1850, PI. XXXVII, Fig. lO, Lord Rosse has given a drawing of this nebula on which is shown a ring separating the apex from the body, but the photogi'aph does not indicate that appearance. NEBULA ^ IV. 28 CORVI. R.A. llh. 56m. 46s. Decl. 18° 19'-2 South. Epoch 1900. Scale — one millimetre to twelve seconds of arc. References. N.G.C. 4038-9. G.C. 2670-1. h 1052-3. Ip IV. 28. In these references the nebula is described as two nebulae, but Lord Rosse, in the Phil. Trans., part 3, 1861, p. 724, PI. XXVII.. Fig. 18. depicts and describes it as a spiral which in outline corresponds with the photograph hereto annexed. The photograph was taken with the 20-inch reflector on April 25th, 1900, between sidereal time llh. 42m. and 13h. I2m., with an exposure of the plate during ninety minutes, and it shows the nebula to be a right-hand spiral with fourteen or fifteen star-like condensations in- volved in the convolutions, one of which (or probably two or three images overlapping), forms the nucleus, and there is shown on the negative extensions of faint nebulosity in the north preceding, south, and south folloioiiuj directions. There are some deviations from the symmetrical form on the north preceding side, both in the convolution and in the star-like condeusations involved in it, and ere long, measurements of the position angles, distances, and fiducial places of reference between the condensations and some of the normal stars surrounding the nebula will be published. Then by aid of the photographs, of diagrams, and of tables of measurements from such fiducial stars, the astronomers of the future will be well equipped for Sliding out the changes and the progressive development of this and of other spiral iiebuliB into star-clusters, or else into systems of stars similar to the innumerable curves and lines of stars which photographs have revealed to us as large constituents of the system of the Milkij Way. I have now many photographs of spiral nebu!;e ready for treat- luent in the manner hero indicated, and have no hesitati(m in saying that the most promising field for astronomical investigations in the present and in the immediate future will be that in connection with the spiral nebulie, the result of which will be demonstration of the evolution of stellar systems in this manner from roaming clouds of nebulous or meteoric matter in the expanse of space. NEBULA MESSIER 61 VIRGINIS. R.A. 12h. 16m. 48s. Decl. 5° 1'7 North. Epoch 190O. Scale — one millimetre to twelve seconds of arc. References. N.G.C. 4303. G.C. 2878. h 1202. Ijl I. 139. Rosse, Ohs. of Neh. and CI. St., p. 113. Phil. Trans., 1833. PI. XV., Fig. (■,9, and 1861, PI. XXVII., Fig. 21. The photogra])h was taken with the 20-inch reflector on May 7tli, 1899. between sidereal time I2h. 22m. and 14h. 25m., with an exposure of the plate during two hours and three minutes, and it shows the nebula to be a right- hand spiral viewed in a direction nearly iierjiendicular with its plane. It has a bright stellar nucleus, and several faint condensations in the convolutions, and two stars in the nebulous spaces between them ; there are also two prominent tangential projections of nebulous matter ou the north following side with a star at each termination, and they suggest the idea of projection by centrifugal force. Similar appearances are also seen on the ]ihoto- graphs of the Great Spiral Nebula M. 51 Canum (pub- lished in I.R. Photos, of Neb and CI. <•/ Stars, Vol. II., PL XV.). There is also shown ou the photograph hereto annexed a small faint spiral nebula with a stellar nucleus and three or four condensations in the nebulosity, thirty- two seconds following and 5'9 north of M. 61, which is not recorded in the catalogues, and therefore may not have been observed before. THE SECOND SERIES OF LINES IN THE SPECTRUM OF HYDROGEN.' The presence of a second series of hydrogen lines, in addition to the ordinary series, in the spectrum of ^ Puppis, was announced in Circulars Nos. 12, 16, and 18. Acciu'ate wave lengths could not then be determined for the less refrangible lines. Since then, measures have been made of six photographs of spectra of K Puppis, and two of spectra of S Orionis. Following the notation proposetl by Vogcl for the ordinary series of hydrogen lines, the new series may be designated Ha', H/3', lly', etc. A comparison of the wave lengths recently determined with two computed values, is given iu the following table. The first of these is given in Circular No. 16, and is a slight modifieatiou of Balmer's formula. It is 3646.1 nr^^, in whicli n is an even number for the ordi- nary series of hydrogen lines, and an odd number for the additional series. The second formula is ^ = A + B -, + C -,. This form was proposed by Kayser, immediately after the announcement of the • Abridged from " Uarvai-d College Observatory Circular," No. .'JS. 182 KNOWLEDGE [Al-glst, 1901. discovery of this series of lines. If we accept this formula, it would appear to be the true law connecting their wave lengths, and would render them comparable with those of other elements. The designation of the lines is given in the first column of the follow ng table, and the wave lengths derived by Mr. King in the second column. The next two columns give th« value of », taken from the sixth column of the table in Circular No. 16, and the computed wave lengths taken from the seventh column of the same table. A similar comparison 1 1 with the formula ~ = 'J74t>l — 121 71*0 ;;;,, — 352010 is contained in the last two columns of the table. Ill'S. (IliS. 5 Comp. m. Comp. Ha' 10128.1 3 10435.2 un- 5413.0) i .5413.9 4 5413.0 Hv' 4.-)42.4 'J 4543.6 5 4540.1 H5' 42U().7 11 4201.7 6 4200.6 IN' 4026.0 13 4027.4 7 4027.5 Hi' 3924.0 15 3925.2 8 3925.8 "V 3-60.8 17 3859.8 9 3860.6 Jifl' 3S15.7 19 8815.2 10 3815.4 11,' 21 37^3.4 11 3782.1 a 3640.1 V 3641-5 On the whole the observed values agi'ee more nearly with the first formula than with the second. This is remarkable, if it does not represent the true law, since this formula contains no arbitrary constants. There IS only one constant, and that is determined with great ,'ucuracy from the ordinary series of hydrogen lines. The second fonnula contains three arbitrary constants which are selected so as to represent the observed value as nearly as possible. A least square determination was not considered necessary, since the outstanding differ- ences from observation were evidently systematic, and not accidental. The wave length of the line Ha:' differs gi-eatly according to the two formvilas, but no means as yet exist for determining radiations of such great wave length in the stars. Cambridge, U.S.. Edward C. Pickering. February 11th, 1901. [The interest attached to the " second series " of liydrogen lines arises from the fact that they were identified as probably belonging to hydrogen by a purely mathematical process. It is a remarkable circumstance that we are so much indebted to a study of the celestial Ixjdies for our know- ledge of the spectrum of hydrogen. Even the ordinary series of lines in this spectrum was first recognised in its entirety in the jjhotographic spectra of white stars, but unlike these, the new series has not yet been reproduced in terrestrial experiments. Carrying Prof. Pickering's inquiry a step further, Rydberg has concluded that there is still another series of hydrogen lines, of which the only one in the visible spectrum is about wave-length 'J6S7.S; this also has not yet been artificially repro- duced, but tlierc is evidence that it is represented by an important line in the spectra of some of the Wolf-Rayet stars and planetary nebulae. The Ihrce scries of lines of hydrogen thus differ from tlie corresponding series in the case of many other elements, inasmuch as they do not all appear simul- taneously in the spectrum of the gas in laboratory experiments. — En.] Hcttcr. [The Editors do not hold themselves responsible for the opinions or statements of correspondents.] • LUNAR ATMOSPHERE AND OCEANS. TO THE EDITORS OF KNOWLEDGE. Sirs, — It has been considered (Proctor's " The Moon," pp. 263-265) that the theoiy that the hypothetical oceans and atmosphere formerly possessed by the moon have been withdrawn to internal cavities is untenable — though the existence of such cavities seems probable enough — since they could not be large enough to contain the volume of an atmosphere sufiicient in cjuantity ever to possess any considerable density on the moon's surface. Also, it seems very improbable that the surface is at a sufficiently low temperature during the day to allow the atmosphere to remain always in a liquid or solid state on the surface. Now might we not combine tliese two theories with advantage ? If all the moon's heat has been lost, any cavities in its structure must be at a temperature sufficiently low to reduce all gases entering them to the solid state ; and these cavities, a few miles from the surface, will not be appreciably affected by solar heat. The cavities, which must be supposed to be in connection with the surface to some extent, would be full of air. When their temperature became suflaciently low, this air would liquefy, leaving an almost empty space. Into this space there would be a constant slight influx of gas throughout the day, the liquefaction, or, later, solidification of which would leave room for fui-ther quantities of air. If the temperature of the moon's mass has become equal to that of surrounding space throughout, may we not suppose that the whole, or very nearly the whole, of the atmosphere, as well as the oceans, may not be within the moon's mass, in the solid state, assuming, of couree, that they have had an existence at all ? The small cjuantities of heat introduced would be lost by con- duction through the surrounding material, and could never, of course, stop the process. J. O'May. BRiTfSFt \, /T\:_ ■ ornithologYca ^^z^ ISk " V NOI£S::-_J Conducted hy Harry F. 'WiTnERBY, f.z.s., m.b.o.d. Red-fackd Variety av the Yellow Hammer. — At the meeting of the British Ornithological Club, held on June 19th, Mr. H. E. Dresser exhibited an aberrant fonn of Eniberiza citriuella, with chestnut-red colour on the throat like the Pine Bunting (Emheriza lencoceplmlit). The specimen was olitained by Mi-. E. S. Montagu in Cambridgeshire. Mr. Millais and Mr. Walter Rothschild also exhibited British examples of this aberrant form. In AciiDST. 1901.] KNOWLEDGE. 183 the L-oui-se of some i-emavks in the Ibis (July, 1001. p. 453), upon a simihir specimeu obtained at Yeni.seisk, Mr. H. L. Pi>pham writes that Mr. Zarudny "considers that this variety points, to some extent, to atavism, and sujigests an earlv ancestral form of E. citriiiellit. nearly related to E. leiicoctphahir—H. F. W. Attempt to re-introdvce the Gijeat Bustard in Norfolk. — Your readers are aware* of the attempt i-eccntly made to rc-introducc the Bustard into its old liannts on the borders of the counties of Norfolk and Suffolk, and that a number of these birds were sent from Spain to the care of Lord Walsingliani. to whom the management of the interesting experiment was entrusted. Fifteen of these birds have survived the winter at Elveden. where they were jJaeed on the estate of Loi-d Iveagh and allowed a run of some 800 iieres of the same country which the indigenous race formerly frequented. All seemed going on well, but, unfortu- nately, the birds, which had become very tame, left their secure retreat and seem to have spread over tlie country - -the I'esult was, as it was too much to be feared, that two of them have been killed, and that by a game- keeper at Finuingham, who of all persons, the experi- ment having been largely advertised, should have aided in protecting them. Of coiu-se the naturalists of Norfolk were gi-eatly disgusted at this unpardonable act, and immediately drew the attention of the Society for the Protection of Birds to the infraction of the Game Laws, and I understand that the man is to be proceeded against at the nest meeting of the magistrates at Eye, Suffolk, for shooting game out of season. The punish- ment of the man, if convicted, will certainly be alto- gether inadequate, but the publicity thus gained may prevent others from repeating the offence, and to some extent protect the remaining thirteen birds which are at large should they not also have been killed, and their destroyers, warned by this example, have concealed the fact, which is too much to be feared. — T. Southwell. Norwich. [It is reported that Arthur Larkings, gamekeeper, Westhorpe, was convicted of the above offence at the ITartismere Petty Sessions, on July 8th. and fined the full penalty of one pound per bird, with £2 15s. costs, or in default one month s hard labour. W. H. Read, keeper to Lord Iveagh, remarked that of seventeen Great Bustards imported only seven remained. As Mr. Southwell predicted, the"" penalty . for Larkings' abominable deed is wholly inadequate, especially as the birds themselves cannot be confiscated. The law as it at present stands is altogether too weak to prevent these murderous acts. Is there no ornitholofrist in Norfolk of sufficient strength and courage to take the law into his own hands and administer a punishment to fit the crime?— H. F. W.] Kreedinii nf Wigenn in Ireland (Irish yaiwalist, July. 1901. p. J47).— Mr. Robert Patterson lias t)ie satii-iaetioii uf beina the first to i-eeonl tlie breediug of the Wigeon iu Ireland. The bird ha3 been >nsj)ected of breedinj; there, but the e^gs ha^e never before lieen found. Some dueks' eggs which Jlr. Patterson could not identify were sent to him bv Mr. John Cottnev, who found them near Belfast, in May last. J[r, Patterson aeeordingly Tisited the place on May 18, and found a nest nitli similar eggs, from which he Hushed a Wigeon. Mr Usslier luis compared the eggs and down, and " has no doubt whatever that they are Wigeon's." Wliite Wagtail at Sartragh, co. Maifo {Irish Naturalist, Jidy, lOC'l.p. 146) — Mr. Bobert Warren records that Mr. Kirkwood has again this year obsened White Wagtails at Bartragli. Since this AVagtail has been seen during April and May, in the years 1898, 1899, • See Knowiedge, October, 1900. p. 230. 1900, loul 1901. on Bartni^li Island, it may be assmned tliat the west <'Oast of Ireland forms one of its regular migratory routes to the north. Migration of Birth in X.IC. Linrolns/iire ihirlng the Autumtu of 190f). By O. H. futon ilaigh. {Zoologist, June, li'ol, pp. 201-211). — Mr. Ilaigh 's annual contribution to our conteuiponiry is of great value to students of migration. Mr. Hiigli renuirks that " the cliief I'ealuro of the Inst autunui passage «as the almost complete total alisenee of visible migration. . . . No rare birds were met with in the district, but among the scari'c visitors may lie mentioned the liittirn, Ked. necked Phalaropc, Wooilsandpipcr, and Little .\iik," A nunilicr of birds of regular oci'urrencc were i-onspicuous by their absence hist autunui. On the Winter Singinq of the Song-Thrush (Tunhis musiciix). liy \V. Warde Fowler, M..V. '{Zoologist. June, 1901, pp 2 12-21^).- 1 ii a pleasantly writtcu article roumlcd upon personal oliservation. Mr. Fowler collies to the conclusion that the Song-Thrush sings in winter in still open weather when food is easy to get at. He is inclined to think that in the case of mature birds the winter song is a forecast of the coming breeding season, while the' immature may very possibly use their voices only in « hat has been termed " voice-|ilay," Rose-coloured Pastor in Kent {Zoologist, June, 19t)l, p. 22;i). — Mr. L. A. Curtis Edwards rei'ords that an adult male of this irregular visitor to Great Britain was secured on May 14 in Komuey Marsh. Red-footed Falcon in Shropshire (Zoologist, June, 1901, p. 224). — Mr. Jl. E. Forrest writes that an imuiaturc female specimen of this Falcon, which is a summer visitorto Eurojie, and rarely reaches as I ar north-west as Great Britain, was shot near Shrewsbury on May 18. All contribution's to tlie column, either in the way of notes or photoijraphs, should he forwarded to Hakry F. Witherby, at lU, St. (icrmans Place, Black/ieath, Kent. ^otictQ of Boons. ■■ iloKfllOLOGY 01? ,Sl'KRM.\T01"UVTi:S," By .1. M. Coultci', I'H.D., and 0. J. Chamberlain, ph.u. (New York: 1). Apiileton & Co. — This book prcsent.s in a practical and iflforuiing manner comprehen.sive information gleaned from numerous authorities together with original investigations iuid ob.servations of the authors on tlie morphology of sec'd plants. The various chapters are devoted to the treatment of Cyciwlales, Ginkgoales, Coniferales, Gnetales and the Fossil Morphology, Phylogeiiy, and geographic distribution of gymnospcrnis. The provision" of laboratories in regions where the plants are indi genous has enabled their jiecuiiar characteristics to bo studied in a thorough manner, and an increasing amount of attention has been and is being devoted to the subject. Numerous illus- trations render the text clear, and the histological structure as revealed by the microscope is well disiilayed. Tlu' ludgiessivc nature of the investigations and the extent of the ground that is covered by the groups dealt with, precludes finality of know ledge and information, but the present work, which brings many new and interesting facts to light, liius been prepared with great care and discrimination, and is written in a very lucid and intere,stiug manner. "The XoRWTioiAN North Polak Exi'edition, 1893 1896. Scientific Kesult.s." Vol. II. Edit«;d by Fridtjof Nansen. (Longmans, (ireeu & Co.) 30s. net. — This second volume, of .scientific results shows even more clearly than the first that the Norwegian North Polar Expedition was not merely an attempt to reach the Nnny can afford. But the book will serve as an excellent work of reference in the drawingotKee aud workshop. •• Dks(.h.vski."s X.xTiR.vL I'uii.o.'ioi'HV." Part 111. Klectrieitv. Prof. J. U. Kverett. .\t..v., D.C.L.. f.R.s. (Blaekie & Son.) 1901. -Desehanel's work has been a standard stuilents' book for many years through the translation made by Prof. Kverett. In this [wrt. which is devoted to Klectrieily and Magnetism, the amount of prognss t« be ivport< Rnidm dt I'icadernie des Sciewes, Fans. The conclusions of the author, Monsieur Gain, are distinctly opposed to those 186 KNOWLEDGE. [August, 1901. of AlpboDse de Candolle, who did not consider it im- possible that a seed may preserve its vitality for fovir or five thousand years ; and the testimony of Count Sternberg, who believed that he had actually procured the germination of tvifo grains of mummy wheat, is dismissed as valueless. It is shown that in oi'der for an old seed to genninate three conditions ai-e necessary : First, the reserve material must remain chemically intact, and this is the case in many grains of mummy wheat and bai-ley ; second, the embryo must retain an organisation so that the enzyme required for the digestion of the resei"\'e material may be produced : and third, if the preceding condition is realised, it would also be neceSsary that the embryo should remain in con- tact with the reserve material. In the seeds examined the embryo no longer existed in contact with the albu- men, and though it retained its cellular organisation, each cell had undergone a chemical change indicating the death of the embryo at a remote period. The author concludes that grains of mummy wheat and barley, in spite of their external appeai-ance of good preservation, do not possess a cellular organisation compatible with germination. — S. A. S. — » > I — Entomological. — Some interesting researches under the dii'ectiou of Dr. A. Weismann, and published by him in the Aiiafow. Air.eiger (Vol. XVIII., 1900. pp. 492-9), confirm the well-known view that the unfertilized eggs of the Honey-bee develop into drones, while the fertilized eggs always give rise to queens or workers. Considerable doubt has lately been thrown on this doctrine by practical bee-keepers, but the question seems altogether set at rest by Weismanu's examination of over 300 eggs in the stage (that of the " second maturation spindle ") when the sperm-aster, if present, can always be detected. In every one of the 62 eggs from worker-cells examined a sperm-aster was found ; while only one of the 272 eggs from drone-cells contained a sperm-aster, t-nd this was almost certainly due to a mistake on the part of the queen-bee, who is able to lay either fertilized or unfert-ilized eggs at will. The development of the eggs and other cells in the ovar}' of the Queen-bee forms the subject of an exhavistive paper by \V. Paulcke in the Zonloq. Jahrb. (nbth. f. nnnt). XIV., 1900, pp. 178-202, pis'. 12, 12a. 13, 13a. In the thread-like ends of the ovarian tubes are numerous undiiferentiated nuclei embedded in a common proto- plasm. Further down the tubes some of thsee are seen to give rise to the cells of the follicular epithelium, while others foi-m the eggs and the yolk-cells. The eggs and yolk-cells are formed by repeated division of the primi- tive germ-cells — forty-eight yolk-cells being produced for each egg, and the cluster of yolk-cells becomes separated from its neighbouring egg-cell by a follicular layer. The yolk-cells at first sliow marked growth and produce food-material which the egg absorbs by pro- truding a process into the yolk-follicle. Ultimately. l>cforc the eggs enter the oviduct, the yolk-cells pass :iito the egg-follicle and become entirely engulfed by the gg-protoplasm. — G. H. C. — * * I — Zoological. — By fax- the most important event we have to record in this column, so far as vertebrate zoology is concerned, is Professor E. Ray Lankester's exhibition before the Zoological Society of the skin and skull of the new mammal lately discovered by Sir Harry Johnston in the eastern borders of the Congo forest. The professor fully confirmed Sir Harry's opinion as to the intimate affinity existing between the okapi (as the new animal is called by the natives) and the extinct Helhidotlieriutn of the Tertiary deposits of Greece. It is believed, however, to be generieally distinct, and the name Ol-apia johnsfoni was accordingly sviggested as its designation, the specific title having been previously proposed by Mr. Sclater, on the evidence of two pieces of skin sent home at an earlier date by Sir H. Johnston. The animal appears to be a com- paratively short-necked, and short-legged representative of the giraffes; the general colour of the upper-parts being purplish-brown, with the thighs and upper part of the legs transversely striped in a somev.-hat zebra-like fashion. The skin, which has been mounted by Eowland Ward, Ltd., will probably be on exhibition at the Natural History Museum by the time these lines appear. For fuller details regarding this most interest- ing creature, we must await Prof. Lankester's promised memoir ; but it may be observed that no such important discovery has taken place within the memory of the jjresent generation. It is noteworthy that the Grecian deposits which vield TIeUadothcriiiiii also contain remains of giraffes. In an ai'ticle published in the Jvine number of the (hologicaJ Magazine, Dr. C. J. Forsyth Major discusses the acquisition by the female of secondary sexual characters originally distinctive of the male. He shows, for example, that the females of the oxen were originally hornless ; and that in those antelopes in which horns are present in both sexes they were originally restricted to the males, as is still the case in many genera of these luminants. Of especial interest are the author's obser- vations relating to the antlers of the deer, which, as is well known are, with the exception of the reindeer, normally restricted to the stags alone. It is pointed out that in one district of Kussia reindeer hinds are reported to be still devoid of antlers ; and evidence is adduced showing that in the roedeer the female is now tending to acquire antlei-s, those appendages being frequently developed in that sex at all ages. Visitors to the palseontological galleries of the Natural History Museum cannot fail to be struck with the skeleton of a huge, half frog-like, half salamander-like extinct reptile from South Africa, labelled Fariasaiiru.<. iritherto these strange creatures have been regarded as exclusively African, but news now comes of their dis- covei-y in Russia. This is a fact of the highest importance to the students of the geographical distri- bution of animals. '^^e wish every success to the Fifth International Congress of Zoology, which is to be held in Berlin from the 12th to the reth of August. A good progi-amme has been arranged, and a large number of papers for reading have been promised. On August TTth Hamburg and its excellent Zoological Gardens and jSIuseum will be visited by those who care, while on August 18 there will be an excursion to Heligoland. Polar Exploration. — The present year promises to be a record one in the way of Antarctic anfi Arctic Expeditions, as whilst four sail to explore the former regions, no less than ten will be at work in the opposite parts of the globe, viz. : (1) The Ziegler-Baldwin Expedition from America, attempting to reach the Pole : (2) the Russian Expedition, under Admiral MakarofI, on the famous ice-breaker " Ermak, " built m England, exploring the regions between Spitzbergen and Novoya Semlja; (3) a Canadian Expedition under Capt. Bemier, of Quebec, sailing north from St. Johns with the object August, 1901.] KNOWLEDGE. 187 of reaching the Polo rid Smith Sound; (-1) a German Expedition from Hamburg with the same object by another route; {o) the " Capella " Expedition to Frauz Joseph Land in search of the missing men of the Duke of the Abruzzis Expedition.; (6) the Peary Expedition in North Greenland; (7) the " Fram " Expedition under Capt. Johaunesen, of Nansen Expedition fame, in the same regions ; (S) Dr. Stein's Expedition in Ellcs- mere Land, returning this year; (9) Baron Toll's Expedition, which sailed last year in order to attempt to reach the Pole by Xausens roiite, rid the New Siberian Islands and the mysterious " Wrangel Land, " and, finally (10) the Swedish Expedition to Spitzbcrgen. The object of this last expedition is to measure the arc of the meridian, a work commenced there last year in conjunction with a Russian station in another part., tlie location of which will depend on the state of the ice. The expedition left Tromso, in Norway, early in June, on board the well-known whaler " Antarctic," and returns in the autumn, when this vessel will cany the Nordenskjiild Expedition to the South Polar Continent, and will thus in the same year have sailed both the Arctic and the Antarctic seas. MEN AND MICROBES By E. Stenhouse, a-R-C-s,, b.sc. The end of one century and the beginning of a new one seems an appropriate time for a stock-taking of pro- gress— a time when we may usefully pause to estimate, to the best of our ability, the position in nature to which " civilisation '' has brought us. In such a mental survey at the present time nothing is more striking than our recognition of the fact that our daily lives are intimately bound up, for weal or woe, with the activities of countless hordes of tiny beings whose very existence was undreamt of a hundred years ago. Bacteria or microbes are as ubiquitous as anything well can be. They occur in the water we drink, in the air we breathe, in the soil beneath our feet, and even in the interior of our own bodies. Were it not for the many services thej' continually perform for us, our life would be quite impossible ; and, on the other hand, they have been proved to be responsible for the greater number of the infective diseases to which we are subject. So minute are the possessors of these boundless powers for good and evil, that it is often necessary to magnify them some 800,000 times before they can be seen at all distinctly. To give some idea of this enormous magnifi- cation, it may be mentioned that an ordinary cigarette magnified in the same- proportion would appear seventy yards long and about twenty-eight feet thick. A bacterium of the cigarette-shape is known as a bacillus. The place of the tobacco of the cigarette is taken by a jelly-like substance called protoplasm ; and the cigarette-paper is represented by an envelope which, however, covers in the protoplasm completely — at the ends as well as at the sides of the bacillus. Many bacilli possess threadlike outgrowths, by the lashing of which they are propelled through any liquid in which they mav find themselves. Other forms, called spiriUa, move bv a serpentine twisting of their slender bodies ; and yet other bacteria are globular in shape and are known as cocci. When a bacterium is full grown, it multiplies by breaking up into two or more pieces, each of which becomes a complete bacterium. As a bacillus becomes adult in half an hour, or less, one individual can thus give rise to about 17,000.000 in twenty -four hours. When the supply of food runs short, or the surroundings become in other respects unfavour- able, many bacteria form themselves into spores, which possess very great powers of resistance. They remain in the resting stage until the hard times are over, and then, with unimpaired vigour, resume their ordinary mode of life. Of the many useful services which bacteria perform, perhaps the most conspicuous is that of breaking up refuse animal and vegetable matter into harmless and often useful substances. That the putrefaction of organic matter is really due to minute and air-borne forms of life was proved conclusively by Pasteur and Tyndall about the middle of the nineteenth century. It was shown that if well-boiled broth is kept in vessels from which the air is either wholly excluded or so admitted that all floating particles are arrested, no ])utrefaction occurs, and the bi-oth lemains sweet for an indefinite time. The importance of bacteriological research is per- sistently forcing itself upon the attention of municipal authorities, not only because it shows how disease- epidemics may be best prevented and stamped out, but also because it indicates solutions of such important problems of public health as the disposal of sewage^ Various modifications of the biological treatment of sewage are already at work in this country, and are giving very encouraging results. Essentially, the process consists in passing the sewage — which may previously have been partially purified by allowing the grosser particles to settle in tanks — through filter-beds of clinker or broken coke. A scum soon forms on the coke, and microscopic examination shows that the scum swarms with myriads of bacteria. The bacteria break up the foul organic matter into harmless substances. The efficacy of their work may be judged by the fact that of several effluents I have recently analysed, the putrescent organic matter had on the average been reduced to less than one-seventh as the liquid was trick- ling through the coke. It has been found that bacteria play a most important part in enriching the soil with nitrates, a very necessary food of plants. Generally the raw material consists of the simpler compounds of nitrogen — those of ammonia, for example ; but the roots of leguminous plants eontaiii bacteria with the very remarkable power of taking nitrogen directly from the air and putting it at the disposal of the plant. The propriety of including yeast-cells with bacteria is, perhaps, questionable ; but the indirect influence upon frail humanity of these minute manufacturers of alcohol is so great that they can scarcely be ignored hero. It is becoming widely recognised that several species of yeasts exist, and that success in brewing depends largely upon the rigorous exclusion of the " wild " varieties. The careful work of the brewer may be biought to naught in a few horns by the activities of another microbe, should it gain access to the finished beverage. The vinegar-organism, as it is called, attacks the alcohol and changes it into acetic acid. Neither beer nor wine ever " goes sour " of itself, if this little plant is absent. Similarly, milk is turned sour by the lactic acid bacillus. Slill others give their characteristic flavours to butter and cheese ; and it has even been asserted that many of the changes which tobacco undergoes in curing and mellowing are due to the action of bacteria. Certain workers are at present investigating this important 188 KNOWLEDGE. [August, 1901. poiut, with the object of breeding pure cultures of the races to which a good cigar may owe its peculiarly seductive aroma. These are a few only of the almost numberless cases iu which we are indebted not only for our luxuries but for the very means of life itself, to the silent but ceaseless labours of these tiny organisms. Moreover, if there is anything whatever in the theory of modification by descent, we ought to be able — considering their fabulous rate of multiplication — to bring about in a comparatively short time changes in the structure and habits of some of our " tajue " bacteria which will make them minister to our health and comfoi-t to a degi-ee hitherto un- dreamt of. Whilst, however, we freely admit our great indebted- ness to bacteria, we must not forget that their powers for evil are also enormous. In 1849, Pollender discovcied minute rod-like bodies, one four-thousandth of an inch long, in the blood of animals which had died of anthrax or splenic fever, and he suggested that these tiny rods bore some definite relation to the disease.* Fourteen years later Davaine announced that the rods were living plants, and that blood contain- ing them had the power of passing on the disease to another animal inoculated with it; while blood from which the bacilli were absent had no power of confer- ring the disease. About 1876 Koch discovered how to grow the organism outside the body ; and Pasteur sub- sequently found that by keeping artificial cultures of the anthrax bacillus at a temperature slightly above that of the blood the organisms gradually lost their deadly power, and after 43 days had no injiu-ious effects upon even the most susceptible animals. After being inocu- lated with such harmless cultures, the animals were sul> jected to the action of cultures of gi-adually increasing strength, until after a short time it was found that they could easily withstand a dose which would at first have proved immediately fatal. The animals had. iu fact, become protected against the disease. This brilliant dis- covery has already been put to very extensive use, and the method of inoculation is now recognised as a certain means of protecting horses, sheep, cattle, and even ele- phants against the ravages of splenic fever. The activities of the anthrax bacillus may be regarded as illustrating the ways of malignant bacteria generally. There is, however, considerable variation in minor details of structure and mode of life. For example, while the rod-shape or bacillus is the form of the organisms respon- sible for anthrax, typhoid, diphtheria, " consumption," and some other diseases, the microbes giving rise to erysipelas are not bacOli, but minute globular bodies (cocci) which stick together in rows, like beads ; and the cause of cholera is a tiny comma^shaped bacterium. While, again, some microbes gain access to the blood, and thus by their marvellous powers of multiplication spread throughout the whole body, others remain at the point of inoculation, and yet set up profound distiu-bances in the system generally which ultimately end in death. The last-mentioned fact, that the organisms themselves may be restricted to one point, while their evil effects may extend throughout the body, suggests that during their life they give off poisonous substances to which, rather than to the bacteria themselves, the diseases are due. This has repeatedly been proved to be the case. , Here, again, anthrax furnishes an instructive example. It has been found possible to prepare from artificial cultures of the anthrax bacillus an intensely poisonous substance, which is nevertheless free from the bacteria ; and this poison or toxin of anthrax induces, if injected into the blood of an animal, all the characteristic symptoms of the disease. Nor is this all. The strength of the toxin can be so regulated that while it is insuffi- cient to cause death, it protects the animal against future attacks. The theoi'y which at present best explains these re- markable facts is that the toxins stimulate certain cells of the body to manufacture substances which neutralise them. These toxin-destroying substances are called nntitocins. Once the cells have got into the habit, so to speak, of producing antitoxins, they continue the work, and lay in a stock which is suificient to promptly render useless the poison-armoury of -the particular race of bacteria, should these again invade the territory. The fact that the terrible zymotic diseases are due to blood-poisoning by toxins, and the possibility that for every toxin there is a corresponding antitoxin — in other words, that every disease produces its own antidote — which may yet be discovered and isolated, are sufficient to explain the tireless enthusiasm with which bacterio- logists have of late years carried on their researches. Marked success has in many cases attended their efforts, and the manufacture of certain antitoxins is now carried on upon a somewhat large scale. The antitoxin of diphtheria, for example, is regularly prepared by a large German firm, and sent out to all parts of the world. The bacilli of the disease are first grown in speciallj' prepared broth for about a mouth, by which time the fluid has become strongly impregnated with the poisonous toxin. The bacteria are filtered off, the clear solution obtained containing the toxin. This is then injected into horses in gradually increasing doses, until the animals can with- stand a large quantity without inconvenience. Then after a few days' rest they are bled from the jugular vein. The whole operation is so carried out that the horses suffer practicallv no pain whatever, and very little injury to their general health. The blood is allowed to clot, and the clear fluid (serum) which rises to the top contains the antitoxin, and is hence known as~anti-diph- theritic serum. It is now injected, iu closes varying with the severity of the disease, into patients suffering from diphtheria. As a result of the treatment the mortality from this disease has been greatly lessened. Antitoxins have also been prepared for protection against and treatment of various other diseases, including typhoid, tetanus (lockjaw), plague, hydrophobia, and snake-poisoning. A few years ago there seemed to be grounds for believing that a cure for consumption had been discovered. The anticipations were, unfortunately, not realised; but the extract of "tuberculin," which it was hoped would rid humanity of its greatest scourge, forms a means of identifying tuberculous cows, and thus of removing one source of the disease. The indictment against these low forms of life is a terrible one. Disease and dirt are, however, closely connected, and the introduction of better sanitary con- ditions will of necessity ext,erminate many diseases. As a rule, only those in a low state of health need fear these minute foes, for they are in nearly every case unsuccessful against vigorous constitutions. The various fluids of the healthy body have a distinctly injurious effect upon malignant bacteria, and it has recently been found that there are in our bodies certain wandering cells which in health act as policemen, promptly seizing and devouring the harmful microbes which do gain access to the system. The tonsils, for example, are crowded with these guardian cells. Arr.rsT, 1901.] KNOWLEDGE. 189 The fact that during tlie progress of a disease the blood acquires properties iniinieal to tlie gi-o\vtli of the bacteria is very marked in the case of typhoid, and affords a means of diagnosing the disease. If we examine microscopically a drop of broth containing a young culture of the typhoid bacillus, we see the deadly plants darting and wriggling about the field in all directions. On diluting the drop with healthy blood-serum, no loss of activity is to be seen, but if the added serum is that of a patient suffering from typhoid, the movements slow down, and the bacilli seem as if paralysed. They collect in separate clumps, strongly suggesting different swarms of midges, and in a minute or two all is over. The bacteria are dead. The sight is, in its way. as striking as anything I have seen. It irresistibly brings up before the imagination the fierce struggle which goes on when disease-germs invade the body. Should they escape arrest by the '' policemau-cells,' they begin their deadly work, but all the reserve forces of the invaded country are called out. The intruders have first to fight against the healthy fluids of the body. If the.se are unsuccessful the bacteria live and niultipjy and give off their poisons. Immediately, however, the body responds and brings forward a supply of antitoxins. Then it is war to the knife. If the bacteria can produce toxins faster than the body can supply antitoxins, they win, and the patient sinks. The only hope is that, before general collapse has gone too far, a timelv injection of the required antitoxin maj^ put the enemy to rout. The possibility of the last resource is due to the labours of such men as Pasteur, Lister, Koch, and their followers. They have shown that we have to fight for our lives against enemies, unimaginably small, but present everywhere and in countless mjTiad&; but they have also been able to classify the foes into races and nations, to discover their various methods of attack, and in many cases to forge weapons by which these attacks may be foiled. The work is only in its infancy, but there is every reason to believe that its ultimate achieve- ments will do more for the well-being of mankind than any other nineteenth-century discovery. Conducted by >r. I.Cro§s Microscopic Tisiox.^A paper of unnsual interest entitled " An examination of the Abbe Diffraction Theory of the Microscope,'' was submitted for the consideration of the Royal Microscopical Society by ^Ir. J. W. Gordon, at the meeting held on June 19th last. It was sought to demonstrate that many of the experiments on which the Abbe theory is based were fallacious and incorrectly interpreted, and new ideas con- cerning the formation of the microscopic image were given. It would be impossible, in the space at my disposal, to give even a brief rei^urne oi the paper, for it will occu])y probably tifty pages of the Society's journal, added to which I have not an advance copy of it before me, and only had an opportunity of examining it for a short time during the few days it was at my disposal. To do it justice, it will require to be read with consideration, and the experiments described actually worked out. A paper of this description is of immense value, because it brings prominently before present-day microscopists straight- forward statements which each can for himself verify or disjirove, and, by comparing them with Abbe's exiieriments. gain considerable information on this interesting subject. The matter will surely give rise to discussion, and it is to bo hoped that a tangible result may follow. So far as the Abbe theory is concerned, it has to bo borne in mind that Abbe's original pajjors were written more especially for those who had the bonetit of a (lernian LTniversity training in phj'sics, and the actual experiments which Mr. Oordon in his paper seeks to disprove in some degree were intended, not as a com])lete proi^ ol his theory, b\it as ocular demonstrations of some of his statements such as would appeal to those who had not had such traimng. It has to be remembered further that the whole of Abbe's experiments are based on the assumption that the light used is parallel from a di.stant source, and directly the illuniinant is brought near, as is the case in ordinary microscopical work where a lamp or a sub-stage condenser is used in focus, the whole circumstances .are changed and the experiments cease to convince. The jiublication of the paper will be awaited with interest, for it has awakened a doubt in some minds as to whether the microscopic;d imago that is really utilized is intlucnced more by effects behind the objective produced by its aperture, than by diffraction effects in the object under examination. Under modern conditions of working where a condenser yielding a large .aplanatic cone is used the condition of a self luminous object is practically reali.sed, for in such a case each point of the flame reaches one conjugate ])oint in the flame image, and if that flame image is brought into correspondence with the object, each part of the lamp flame lights one point of the object. AD the points are separately illuminated and are therefore not ca])able of interference in a very marked degree (although as a matter of fact there is slight interference), hence the value of our modern wide aplanatic cones of illumination. PRi;si:uvrN(; .and Mountin'i; Mosv''rroEs. — Some time has elapsed since the connection between mosquitoes and malarial fever was established, yet satisfactory sjieeimens of the former have reached England in very small numbers although medical men and others who are interested in the matter have constantly wished to obtain them. The reasons are that the unmounted specimens are npt put up in suitable preservative medium for travelling, or if they are mounted, sufficient care has not been exercised in the process. Several methods have been pubhshed in medical papers on the subject of preserving mosquitoes, but none of them are really satisfactory ones. The following will be found to answer the purpose : — To send unmounted mosquitoes by post they should be preserved in dilute alcohol, two parts of rectified spirit to one part of water. Too many should not be put into one bottle or they become entangled and broken. To make permanent mounts, dilute glycerine, .say one part glycerine to two parts water, in a shallow cell will be found best. The following is the process : — (1) Remove the dilute alcohol and soak in water until all trace of the spirit is removed. (2) Soak in dilute glycerine for about twelve hours. (3) 3Iake cell, and when dry fill up with dilute glycerine and carefully place the specimens in it and apply the cover glass. Should the mosquito be too opaque after soaking in water, place it in a strong solution of carbolic acid for a few hours, and when transparent wash in water, then place in dilute glycerine. Portable Microscopes. — At this season cf the year when so many microscopists are travelling in search of health and pleasure, attention may be directed to a note on this subject in the April number of the Jotimnl of the Queheti Mii-roacopical CI III,. It has often been remarked that effects can be obtained with large microscopes which cannot be secured with those of smaller size, and the home-worker invariably chooses a model of such large proportions as to render it unfit and inconvenient for carrying on short trips and holidays. The provision of a companion microscope of .small size but yet of a thoroughly .serviceable character becomes very desirable. 190 KNOWLEDGE. [AuGTIRT, 1901. and hours during holiday time which might otherwise be dull and -wearisome, could be rendered profitalile and enjoyable if a microscope were available. The special microscopes to which attention is directed are : — The Diagnostic Microscope by C. Baker, made at the suggestion of Surgeon-Major Ronald Ross, for the diagnosis of malarial fever, etc. ' The American Portable Microscope by Bausch & Lomb, of Rochester, New York, the London agents for whom are Messrs. Staley & Co., Aldermanbury. The Portable Continental and the Portable Star Microscopes by R. e*i .1. Beck. The Improved Clinical Microscopes by Swift & Son. The Portable Microscope by Watson & Sons. The above is practically a complete list of the portable microscopes that are made, excepting only a new one by Leitz. All of them have their points of advantage, either in weight. size, completene.ss of mechanical fittings, or jirice. The makers' catalogues will give full particulars. In passing I feel bound to give S|jecial mention to the very neat and ingeniously made instrument by Swift & Son, refen-ed to in the above list. It exactly fits my idea of a portable microscope. Note on Examin.\tio\ of Blood. — A microscopical examination of a stained specimen of pathological blood implies a comparison with the ap])earance of normal blood when subjected to the same staining process. The experienced observer unconsciously makes use of his mental picture of the normal specimen in doing this work, and to him it is sufficient. In fixing and staining blood-spreads, however, a slight variation in technique may produce a decided difference in results, consequently those who have had comparatively little experience in such work will find it difficult to secure uniform results without a considerable laboratory equipment. In preparing pathological specimens in such cases a spread of normal blood may. at the same time, be subjected to the same technique and mounted on the slide with the pathological specimen, making exact and reliable comparison a very easy matter. Dried blood-spreads can be kept indefinitely, so a supply of normal specimens can easily be held in constant readiness for use. NOTES AND QUERIES. E. A. .lonex. — I am sorry I cannot direct you to a source for PalcKolithic flint implements, but if you were to communicate with JMr. T. Russell, of 78, Newgate Street, he would no doubt be able to put you in the wa}' of obtaining them. W. P. Williams. — A micro-scope suitable for general purposes and for the study of rocks and minerals need not be of special construction. It should have a stage that rotates concentrically, and this ought to be provided with screws so that it could be centred to any objective, or alternatively, a nosepiece with centering screws to attach to the lower end of the microscope tube and receive the objectives. You would need a polariscope ; the polariser should have its rotating circle divided and a con- denser system attachable over the prism to come flush with the / surface of the stage. If you already have a substage condenser of large aperture, the ])olariser could be arranged to work with that. The analyzer would probably be found most useful if mounted over the eyepiece, and this also could have a divided circle attached to it. Extra fittings for petrology, such as a calcspar plate, Bertrand's lens, etc., would be applicable to an ordinary microscope equipjied as above. If I can aid you further I shall be glad to do so. Communications and enquiries on Microscopical inafters are cordially invited, and, shonld he addressed to M. I. CliOSS, Knowledge Office, 326, Hi(ih Holhorn, W.C. NOTES ON COMETS AND METEORS. By W. F, Denning, f.r.a.s. Naked-eyk Comkts. — These objects ccrtaiiilv :i|>)i('in' inni-r cil'li'ii than is gencnilly .supposed, bift the circ'iimstauc-es arc luifavciimihlc and the apjiaritions brief. A conspieuoiia (^omet i.s rarely prpsontod tinder the best conditions, but when these ooriir, the sticclacle is lout; ivnienibered as one of special intei'est. Amon^ tliosr conii'ts wlucli were well exhibited from un obscrvalioiial |)oirit of view in:iv be instanced Donati's 1858, Coggia's 1874, Tebbntt's 1881, so. Certain other fiiu! comets were seen by few persons, and have now almost entirely passed out of memory owing to the dilliculties which attended their observation. On an average, a comet is visible to tlie naked eye UTnumlly, for since the beginning of 1880 mor^ than 20 of these olijtM'ts liave been recorded, the list ijeing as follows: — Yi-iir. Month. Comet. 1880 Ki'lirniiry Great southern conn't, tail 411". ISHO Octolier" Hartwig. 1H8L .Tune-September ... Tebhutt. fine comet, tail 15"". 1881 Julv-Aunust ... Scliacbt-rle, tail 10^ 1882 Ma'v-June Wells. 1882-.3 October-February ... Great comet, tail 22". 188.3-4 November-JanuaVy Pons (1812). 1881) Ajiril ... "... Fabrv. 1886 May Barn'ard. 1881) No\ ember-December Barnard. 1887 January ... ... Great southern coiucl, tail 35". 1S88 April-Mav Sawertlial. 18S0 .July... ' Davidson. 1892 April-May Swift, tail 20°. 1892 Noveinbcr Holmes. 189;i .Tuly Quenissett. 1893 October Brooks. 1894 April-May Gale. 189.5 Noveniiier-f)eeenil)er Perrine. 1899 Mar<-li-Miiy Swift. IflOl April-May ... ... Great southern comet, tail 1.5°. The tal)lc might be increased by the addition of several other coniets which were Just visible to the naked eye, but in the historical records of these lutdies details are not always given on this point. The Great SonTHEBjj Comet. — This object has now passed beyond the reach of the most powerful telescopes. lliere seems, however, a possibility that it may be re-detected in the early autumn, though the prospect is not an inviting one, the comet being situated at a I'onsidcrablc distance from the earth. Comet Gale (1894, II.). — Definitive elements have been computed by Mr. 11. A. Peck, fi'om more than .500 observations extending o^er the interval of 141 days, from April 2 to August 21. The orbit proves to be ellijitical with a period of 1143 years. The elements agree very well with those derived by the Rev. Dr. Roseby, from observations during 78 days which indicated a period of lOOL years. Encke's Comet. — This interesting object returns to perihelion in September, 1901, but the conditions will not be favourable, and the comet is not likely to be, much observed. At the time of its passage through penhelidn it will be on the opposite side of the sun to the earth. This comet was first discovered by Mecbain, at Paris, in 1786, and at later returns by Miss Caroline Herschel, iu 1795, by Thiilis, in 1805, and by Pons, in 1818. Encke soon afterwards determined its real orbit and jjrcdictcd its retmai in 1822, wliich duly occurred. Since 1822 tbe comet has made 21 returns, each of which has been observed. August Meteoes. — The moon will interfere with observation early in tbe month, but meteors are nsnally so numerous at this eijoch that the observer may gather plenty of materials even in a l)riglit sky. At the time of tbe maxinunn (August 11), and during the later stages of the shower, the circumstances will be more favourable, and with fine weather the display may he well observed. Tlie ])aths of all tbe brighter meteors seen should be recorded, and especially those which belong to the minor streams. In every case it is desirable tliat the direction of Jlir/hf should lie noted with the utmost care and precision, for it is cntirclv u])ou this feature that the accuriu^y of the radiaut ])oiut ilcpeniis. Tbe visifilc ibo'ation of the Perseid shower probably extends to tlie end of the third week in August, but it is extremely difficult to assign the definite limits. In 19(X), the w riter at Bristol saw a radiant of swift, streak-leaving meteors on August 22 at 59" + 59", which corresponds with the probable place of the Perseid radiant on that date, but there is a persistent shower of Canielopardids from tbe same ap})arent position during August, and it is therefore ilonbtful whether the meteors annually seen on about August 21 and 22 are really late members of the great Perseid display. Observations should l)e made between August 17 and 22 with a view .to obtain moi'e evidence on tbe point. Bright Meteor. — On July S a meteor, moving very slowly and with an extremely long path, was observed at Torquay by Miss L. M. Milner, and at Kastbourne by Mr. H. M. Whitley. At Torijuay tbe object passed from a /3 Capricorni to Aries, while at Eastbourne the observed course was from f- Serpentis to Cor Caroli. Tlie radiant was at 253" — 24°, so that it belonged to the .Tune -July Scorpiids. At Eastbourne the meteor was as bright as Jupiter, and its duration was 10 seconds. It fell from heights of 53 to 2t) miles, and its velocity was Ar.usT. 1901.] KNOWLEDGE. 191 about 12 iiiiU'S per soioiul. (.'rossiiig tlu' English Channel the meteor pasrfd near the eiisterii extremity of the Isle of Wight, nml direotiug its llight to X.X.K., linaJly ili-nppeaitil over a point near Goiliilming. The shower of summer SeorpiiiU to whieh the meteor beU>iiged, is quite a remarkable one, and special attention to it was called by the writer in Jifromomische yac/irir/ifen. No. 371!'. THE FACE OF THE SKY FOR AUGUST. By A. Fowler, f.r.a.s. The Sun. — Ou the 1st the sun rises at 4.'Jo, aud sets at 7.47; ou the 31st he rises at 5.13, and sets at 6.47. The disc should be carefully watched for spots. The Mooy. — The moon will enter last quarter ou the 7th at y.2 A.M.. will be new on the 14th at 8.28 a.m., will ent«r first quarter on the 22nd at 7.52 a.m.. and will be full on the 29th at 8.21 p.m. The following are the oectiltations visible at Greenwich during the month : — 1 1 1 ti r 1' Angle from North. Angle from Vertex. i < "a s o o o , o d. h. Auir. 3 D-M.-So.WSa 6-3 12.58 a.m. 45 58 2.8 A.M. 260 ! 261 18 4 ,,5 5 Piscium 4-6 2.39 A.K. 84 »9 3.47 A.M. 224 225 20 5 ., 6 29 Arietis (io 10.51 P.M. .57 h. I. ... 11 51 > I. Oc. 1). .. 10 29 14th.— II. Ec. K. ... 8 52 5 3l3t.- - I. Tr. I. . 7 39 15th.— III. Tr. I. ... 7 21 I. Sh. I. .. 8 50 I. Tr. I. ... 9 31 I. Tr. E. .. 9 .50 III. Tr. E. ... 10 20 I. Sh. E. .. 11 » ■rly part of Ophiuchus, and T) Ophiui'hi. The Isf at S.S I'.M,. ;ind mi Saturn is also in Sagittarius, a little to the east of Jupiter. He crosses the lucridiau on the 1st at 10.9 p.m., and on the :>lst at 8.6 p.m. On the 13th the a))pareiit diameter of the planet will be 16"-(;, and the major and minor axes of the outer ring respectively 4l"'7 and 17"'9. The northern sjde of the ring is jiresented towards the earth. Uranus remains in the most smitl nearly midway between .\ntari's planet crosses the meridian on the the 31st at 6.9 p.m. Ne])tune cannot be observed ou account of his appaniii proximity to the sun. The Stars. — About 10 p.m., at the beginning of the month, Perseus and Cassiopeia will be in the north-east ; Pegasus, Andromeda, Aries aud Pisces towards the east ; Aquarius and Capricoruus in the south-east; Cygnus ami Lyra nearly overhead; Aquila aud Sagittarius in the south ; Hercules and Ophiuchus towards the south-west ; Corona and Bootes in the west; and Ursa Major in the north-west. Minima of Algol will occur on the 9th at 9.4 p.m., and on the 29th at 10.47 p.m. (!?1)css Column. By C. D. LococK, b.a. Communications for this column should be addressed to C. D. LococK, Netheriield, Camberley, and be posted by the 10th of each month. Solutions of July Problems. No. 1. (A. H. Williams.) 1. B to BS, and mates next move. No. 2. (B. a. Laws.) Key-more. — 1. Kt to K8. If 1. . . KxR. 2. QtoKt3, etc. 1. . . B X R. 2. Q to R6, etc. 1. . . P moves, etc. 2. Kt to B6ch, etc. [The above was the composer's intention, but the pro. bleni admits of three other solutions, by ]. R to K7, 1. K to Q4ch, and 1. Q to R6.] Six points have been scored this month liy W. Nash, W. H. S. M., J. Baddeley, S. G. Luckcock, G. Groom, J. T. Blakemore, W. Jay, G. W. Middleton, W. de P. Crousaz, P. Dennis, G. \V., V. H. Macmeikaii, C. Johnston, A. C. Challenger, J. E. Broadbent. Five points by H. Le Jeune, G. A. Porde (Capt.), H. S. Brandreth, Eugene Henry, H. Boyes, C. V. P.. C. C. Massey. Fovr points by Alpha. Two points by A. E. Whitehoiis.-. C. C. Mnsney. — I cannot follow your reasoning as to Mr. Anderson's problem. After 1. PxB (bt-coming a Queen), P to R8 (becoming a Knight;, it is just because the Black Knight is unable to move that stalemate will result ; sujjposing, that is, that White makes any attem].t to mate. 192 KNOWLEDGE. [August, 1901. Alpha. — 1. B to K7 is answered by 1. ... Q to QBsq. G. W. MicldJetoii.—TwiO keys score full points, whether the composer's intention be (liscovered or not. H. Wood. — The conditions of yonr S Pawns prolilem are given below. N. M. Gihhing. — Many thanks for the ]iroL>Ieni ; it is marked for publication in the autumn. There was no need for the re-introduetion : I remember your former problem and have seen others of your composition. Britigh Chei'st Company. — Regret that it is impossible to arrange a correspondence match on the lines suggested. Mr. H. Wood, of Bolton, sends the following curiosity. Black is to have all his pieces and Pawns arranged in their proper order, as at the commencement of a game. White is to have a King and Pawns only, the former to be on his own square and the Pawns to be jilaced where he likes. How many White Pawns will be required, and where must they be placed, so that Black, even with the move, is mated in five moves or less? Correct solutions will be acknowledged, but the puzzle will of course not count in the solution tournev. PROBLEMS. No. 1. By W. S. Branch. Black (4). W^ ^^ f--/-*";^ '■(m g^^ ^ • % White (In). White mates in two moves. No. 2. By W. Clugstou (Belfast). Black (11). Whits (S). White mates in two moves. No. %. By W. IT. Gundry (Exeter). Black OO. w: -M ........... i^^^^ ^..M m,^ ,, ^B^ ^S^ ^B^ White (1:1) White mates in two moves. CHESS INTELLIGENCE. Three counties are left in for the deciding round of the Southern Championship, viz., Essex, Surrey and Gloucester. In playing off the ties Essex have defeated Surrey, as, stated last mouth, but lost to Gloucestershire by 9^ to 6i. Should Gloucestershire succeed in defeating or even drawing with Surrey, they will of course win the championship ; but should Surrey win the match, the county which has scored most won games in its two deciding matches, drawn games being left out of the question, will be declared the winner. We have to record, as a very unusual event, that the Scottish championship has not been won by Mr. D. Y. Mills. In the tournament of the Scottish Association, he tied for first place with Dr. Maedouald, both players scoring 0 games out of 7. In playing off the tie, it was agreed that one game only should be played; Mr. Mills was a Pawn ahead in tlv end game, but made a blunder which lost a piece and the match. The principal event of the Kent Chess Congress, held at Folkestone during the Whitsuntide holidays, was an open tournament for first-class amateurs. The players were divided into two sections, Mr. Atkins winning in Section A, Mr. Serrailier being second, and Mr. J. H. Blake in B. after a tie with Mr. Tattersall. In playing off, Messrs Atkins and Blake drew tlieir game and divided the prizes. Messrs. Mortimer, Wa.inwright and Lowe were among the comisetitors. For Contents of the Two last Numbers of " Knowledge," see Advertisement pages. The yearly bound volumes of Knowledge, cloth gilt, 8g. 6d., post free. Binding Cases, Is. Cd. each ; post free. Is. 9d. Subscribers' numbers bound (including case and Index), 2s. 6d. each volume. Index of Articles and Illustrations for 1891, 1892, 1894, 1895, 1896, 1897, 1898, 1899, and 1900 can be supplied for 3d. each. All remittances should be made payable to the Pubhsher of " KsowLEnoK." "Knowledge" Annual Subscription, througliont the world, 7s. 6d., post free. Communications for the Editors and Books for Review should be addressed Editors, " Knowledoe." 326, High Holborn, London, W.C JSbpthmiiku, liiOl.l KNOWLEDGE. 193 Founded by RICHARD A. PROCTOR. VoL.sxiv.] LONDON: SEPTEMBER, 1901. [No. 11)1. CONTENTS. On the Capricious Hearing of Certain Sounds at Long Range. I'.y tlir Rev. .loiix M. I!ai ox, f.b.a.s. (Illustrated) The Insects of the Sea.— V. Flies. hy Geo. IF. C.lRrKNTF.K. i>.Br.(LOXD.) {Illustrated) ... Round Fain Head. liv Gbenvilie A. .1. C'oii:. m.k.i.a., K.O.S ~ .. The Ringed Plains of the Mare Nubium. By E. Wai.tek MaiM'KB. F.it.A.s. {Illustrated) " The Ringed Plains of the Mare Nubium. {Plate.) The Great Southern Comet (1901 I ). By \V. F. Dbnnixg, f.b.a.s. (Illustrated) Letters : Nova Persei. By A. Stanley Williams DuiBiB Rainbow. Bt R. T. Lewis. Note li_v Eds. British Ornithological Notes. Couducted by Habht K. WiTHEKlli', K.Z.S., M.B.O.U. ... Notices of Books Books Received Obituary :— Eleaxoe A. Objiebod ; Sir Cutubert E. Peek, UABT. M A., F.S A., etc Notes Current Carcinology. By the Rev. Thoma.s H. K SiBBiiiyo, M.A., F.K.S., P.L.S., p.z.s. ( Illustrated J ... Microscopy. Conducted by il. I. Cboss Notes on Comets and Meteors. By W. F. Denning, F.B.A.S. The Face of the Sky for September. By A. Fowi.eb, F.B.AS. ... Chess Column. By C. D. Locock, b.a V.\:\ IIH i:is Ijl HI •Jdl 2C4 L'lU 2111 2(ir> 107 207 20K 2111) 2i:i 21 \ ■2\o 215 ON THE CAPRICIOUS HEARING OF CERTAIN SOUNDS AT LONG RANGE. By the Rev. .Iohn M. Bach.n', f.r.a.s. The last has hardly yet been said a.s to the vagaries of -.oiinds of long range. Dr. Davison has contributed to Knowledge* a graphic record showing how at a great manj' distant places the minute guns fired at Spithcad on February 1st were distinctly audible; some of these places, mainly lying to the N., being upwards of a hundred miles away — while at the same time the sound waves in the immediate neighbourhood of Spithead were almost or quite imperceptible. Commenting on this. Dr. Davison conceives that the sound waves were first of all reflected by contrary winds over the heads of observers, but were aftemvards brought down again by favourable upper currents. The same authority states that the report of guns, distant or otherwise, when inaudible in Portsmouth or Winchester, may often be distinctly heard from the more open or higher ground outside these towns. * Khowlbbge, June, 1901. The bending upwards or downwards of sound waves, which seems to have presented a problem to Sir .lohii Ilorschell, has been explained by Sir G. Stokes a.s duo to the general increase of the velocity of wind currents with hcigiit above the ground. As a consequence of this he maintains that the front of a sound wave moving against the wind will be caused to lean backwards and therefore its direction of nioliun to bo tilted ohli(|uely upwards. Tyndall accepting this theoiy, and taking a. hinged ladder out on to a common, satislicd himself liiat a small bell which had been moved to leeward until its sound was inaudible could be distinctly heard w-hcn he climbed high enough to catch the sonorous waves that were being deflected upwards. It is here that I would offer a few observations of my own as mainly sup])ortiiig the above. On one occasion, when making a balloon ascent from Newbury, I caused I he leiior bell of Tliatcham Clnircli, weighing uinvards (if a ti)ii, and distant scarcely three miles to windward, (o Ijc set ringing as in peal. The wind was a lij^hl breeze, and the balloon iiiaintaiiicd altitudes vaiyini; hetwceii lOOO and tin- ISdDO feet, yet the bell wa.s in- audible to each and all of the four observers in the car. It is true '.hat for the liist few iiiinutes there was much noise in the air occasioned by the shouting of the crowd, but. afterwards we travelled only over quiet agrictdtural country. Another noteworthy phenomenon, to prove which there is abundant evidence, is that when fog- signals arc being fired from the Bishop lighthouse these will sometimes sound so loudlv in the lower part of Hugh Town and Forth Cress.i at St. Mary's Island, eight miles away, as actually to shake the houses, while the reports may be scarcely audible from the high and open ground above. Once again I may mention that the guns which, as Dr. Davison states, were tinheard at Newbury, forty-four miles away in low ground, were also inaudible from my own grounds in the neighbour- hood, which are nearly .500 feet above sea-level. In the above cases due account, must of course be taken of any local turmoil in the air which may have tended to ma.sk the distant sounds. In proof of this I may give a recent ex])criment. A powerful reed was blown at the focus of a large paraboloidal shell, the open moutli of which was directed towards distant clumps of trees in full foliage, when echoes were returned lasting for as much as seven seconds, there being an absence of wind at the time and the summer night well advanced. Other things being equal, however, the same echoes were lost after fovu' or five seconds if there were but faint sounds in the air such as those of bird or insect life. This is tantamount to proving that a local dis- turbance which is scarcely noticeable may reduce the lange of a given sound by almost one-half. Further, it may be a question whether the natui-e of the earth may not in some way affect long hearing. Bearing on this. Lord Rayleigh makes' the suggestive remark : " The propagation of earthquake disturbance,'' he says, " ijs probably affected by the curvature of the surface of the globe acting like a whispering gallery, and perhaps even sonorous vibrations generated at the surface of land or water do not entirely escape the same kind of infiuence. ' Again, surrounding covintry may make a vast difference in redoubling a sound at any given point or else in allowing it to escape. A remarkable instance of this came under my notice lately. For signalling purposes I was firing gun-cotton fog-signals on the open ground at Chcetham Hill, Manchester, between ten and 194 KNOWLEDGE. [September, 1901. eleven p.m. These service signals are uniform in character, and the first, though of the usual intensity, was followed by little after-sound. After an interval occupied only by the burning of two distress signals another gun-cotton charge was fired from within a yard or two of the same spot, the reverberations of this. however, were so peculiar and prolonged as to disturb the neighbourhood. If the great difference of after- sound was not due to the slight alteration of position, it can only be refened to the fact that the first cartridge was fired eighteen inches above the ground, while the second was laid on the hard earth, in which it blew a deep cavity. With reference to the far hearing of bells one most important statement to make is that their sound is extremely uncertain. Seamen, lighthouse keepers and others, whose training makes them close observers, constantly insist on this. I have already shown how remarkably the sound of a bell may be lost in the free upper ah-. Against this may be quoted a statement which I have on the authority of Messrs. Mears, the well-known bell-foundei-s. It appears that the tenor bell of the peal of St. Bees, on the coast of Cumberland, has been heard at the top of Scafell Pikes, sixteen miles distant in a straight line. This is certainly a record, and must probably be largely accounted for by the slope of the mountain. My own experience is wholly against the possibility of the hearing of a deep bell across such distance and at the height of 3000 feet in the free heaven. The stoiy of the sentry on duty on the terrace of Windsor Castle suspected of drowsiness and yet detecting the clock bell of St. Paul's striking thii-teen is quite incredible to one who has frequently and from chosen places of advantage listened to the clocks of London striking midnight. To begin with, hundreds of other clocks are striking at the same period, and for anyone to accurately count out the strokes of any particular bell would require that observer to be very wide awake indeed, and certainly at a nearer distance than twenty odd miles. But a very interesting' and instructive series of observations relative to the heai'ing of a bell heavier by ten tons — namely. Big Ben — has been contributed to the Quarterly Journal of the Roy. Met. Soc. by Mr. William Marriott. This observer, making careful note twice daily from a station in West Norwood, only five and a half miles away, records that the bell was very distinctly heard four times, faintly heard 64 times, and altogether unheard on 251 occasions. A significant comment is added to the effect that the most favourable hours were those of evening and Sundays. Where a bell is chosen for a warning signal, e.g., as on a lighthouse, and it is desired that its sound be carried in all directions over as great horizontal ranges as possible, the most efficient form of sound-board will be found to be that shown in the accompanying figure. Here it will be seen by taking any vertical section of the apparatus that every point on the sound-bow of the bell (i.e., that zone that is in most intense vibration) virtually occupies the focus of a parabolic reflector, and thus the principal sound waves ai-e made to travel out^ wards horizontally in parallel rays. An approximation to the jiaraboloid will be found the best possible fomi for installments designed alike to convey and receive the human voice at long range. Obviously some little compromise in outline will be necessary. The aperture of the car in listening, as also the lips in speaking, should, as nearly as possible, occupy the focus of each instrument. Thus it is clear that the lat-tis rectum should not much exceed li inches, and it will then be found convenient that the larger end of the instrument (which may mea.sure some 14 inches in length) should be somewhat constricted so as to approach a cylindrical form. With a pair of these instruments, forming respectively a giant speaking trumpet and a giant ear, speech can be carried on across an open common on a quiet night over a mile range. Any appreciable amount of wind stirring affects results gi-eatly. A favouring wind scarcely favours the hearing of the voice, doubtless largely owing to the muraiur in the air caused by the wind stirring the herbage, etc. It may be otherwise in the case of a gun. Dr. Davison considers that piesuming the velocity of wind to increase with height the report of a gun might be audible at a much greater distance in wind than in calm. Tyndall points out that in wind a gunshot may readily be lost altogether, but states as an observation of his own that on a windy day a gun was heard five times and might probably have been heard fifteen times, as far to leewai'd as to windward. It has been suggested that the peculiar loudness of some of the repoi-ts heard on February 1st may have been due to the discharge of several guns at practically the same instant. This argument may be valid enough in the case of independent but simultaneous gun firing, but it is only true in a very modified degree in the case of the usual gun-cotton fog-signals already spoken of, and chosen by the service for special penetration. The explosion of an eight>-ounce cartridge is certainly not nearly twice as loud as that of four ounces, while through interference or some other cause the firing of two four-ounce cartridges in juxtaposition is not very greatly louder than that of one. On an occasion when experimenting on echoes I was firing a number of these fog-signals singly from the clouds I designed to' make a superlative discharge by firing a nest of many united together. It chanced that I was able to explode this giant bomb nearly over the racecourse at Epsom at an altitude of about half a mile, the course was deserted, but the nature of the ground seemed favourable for a gi-and effect. I can but state, however, that the result- ing report and subsequent echoes were under the circumstances disappointing. THE INSECTS OF THE SEA.-V. By Geo. H. Caepenter, b.sc.(lond.), A.fsistant in the Museum of Science and Art, Dublin. FLIES. Two-wiNGED flies are perhaps the most dominant of all insects. The woodland rambler in summer-time knows too well what swarms of flies hover with ceaseless September, 1901.] KNOWLEDGE. 195 buzzing around his head. Tho individuals of some one kind often occur in countless numbers, and when tlie fli:?s, now somewhat neglected, have been thoroughly studied, it is likely that their species will bo found to exceed in number those of any other insect-order, not excepting even the beetles. Certainly the naturalist who £;oes to look for insects by the sea-shore in summer-time will first of all be struck by the great abundance of vai-ious kinds of flies. He needs not to search for them, as for beetles or springtails, beneath stones ; they fly and run to and fro in the sunshine with ceaseless activity. Among these insects the remarkable modification of the wings of the hind pair into small stalked knobs or " balancers " [haheref) leaves the fore-wings alone functional as oi-gans of flight. This character marks the flies as a vei-y distinct order of insects, and suggests for them the expressive name of "Two-wings" (Diptera). In many points of structure flies are the most highly organised of all insects, and their great specialization of form is mat<:hed by a gi'eat complexity in the transforma- tions that they undergo. The most highly developed members of the order begin life as degraded, headless, leg- less maggots. The skin of the full-fed maggot hardens to foi'm a brown, egg-shaped puparium, within which fii-st the pupa and then the perfect fly is built up by a pro- found dissolution and reconstruction of the larval tissues and organs. The despised housefly and blue- bottle are proclaimed therefore by their structure and life-history to belong to the highest aristocracy of the inscct>world. Out in the open air one may meet with many hundreds of different kinds of flies more or less related to om- well-known guests just mentioned. A vast number of these, which differ from the blue-bottle and its immediate allies in the absence of the silvery scales at the base of the wings, are often spoken of collectively as the " Acalypterata." Quite a little assemblage of these insects haunt the shore just above high-water mark, finding in the cast-u]) seaweed a playground for them- selves, and a feeding-place for their offspring. They are very nearly related to the bright yellow, hairy, red-faced flies of the genus Scatophaga, which may be observed any sunny day in vast numbers hovering over dung- heaps. Fucellia fticorum (Fall.), the closest ally of Scatophaga among them, is a small, inconspicuous ashy fly, common on our coasts, and ranging along the western and southern edge of the Continent from Norway to the Adriatic. One other species of Fucellia inhabits our shores, but there are seven or eight Fig. 1. Fig. 2. Fig. 1. — Coelopa pilipfs, male. ilai;ui6ed 3 times. Fig. 2.— Orygma luciuosa, male. Magnified 3 times. different kinds known from the far north of the Scandinavian peninsula — Lapland and Finmark. The flies belonging to Coelopa (Fig. 1) and its allied genera have a most characteristic aspect with their narrow. angular heads, small eyes, aud flattened, depressed bodies. They all have stout and powerful legs, which in some species are armed with a most formidable array of spines, while in others they arc clothed with a dense setting of long, woolly hairs. The distribution of Coelopa is remarkable. Five or six species inhabit tho British and Irish coasts, of which most have been traced to Scandinavia, but only one or two range southwards to Holland and Heligoland, so that the genus is charact-eristically north-western. Of similar distribution and habits is Orygma /iirtunm, Meig. (Fig. 2), a some- what larger fly than the Coclopae, and distinguished from them by its broad, rounded head.* Artorn aestitum, Meig., is a still larger fly of an ashy grey colour, less differentiated from related insects than are its comrades of the soa^shore. It is of especial interest since its grub has been described, t and proves to be a greyish maggot with wrinkled skin, fourteen prominent, conical, flesliy processes sunouiiding the air-openings at the tail-end. This as.somblage of flies, some of whoso leading members we have briefly sketched, though few in species, is often vei'y numerous in individuals. On a sunny day, when the tide is high, the observer has but to lie on the beach to watch the ceaseless darting flight of the insects over the seaweed-heaps. Many of tho flies follow the receding waves, so that at low-water they may be seen running over the recently exposed rocks or alighting after a short flight on the still damp seaweed. Many very small flies, belonging to the samo great group as those just considered, but to a most distinct sub-family, the Ephydrina?, also haunt the searshore. As usual, a transition can be traced from marsh- dwelling species to those which cling to the tidal margin. Thus the tiny Alissa pygmaea, Halid. lives in salt marshes. Tichomyza fusca, Macq. is found both on chalky coasts at high-water mark and in the sewers and outhouses of large towns, its grub feeding on decom- posing limy material. Glenanthe ri/ricohi, Ilalid. (Fig. 3) Fig. 3. Fig. 4. Fig. 3. — Glenanthe ripicola, male. Magnified 8 times. (After Ualiilay.) FlO. 4. — Ckersodromia arenaria, male. Magnified 12 times. dwells on muddy sea^coasts, while nearly all our native species of Scatella live among the seaweed masses • SeeJ n Sehiuer. " Fauna Austriaea, Diptera." Wien, 1861-4. F Walker [Si A. 11. Ilaliday]. "Insecta Britanni^a, Diptera ' 3 vols London, 1851-(5. Q. H. Vcrrall. " A List of liritisli Diptera. London, 1888. ■»«■ • i> t H Gadeau de KerviUe. "Notes sur les Larves Marines d un Dipttr;.- Ann. Soc. Ent. Fr. (Vol. LXIII.), 1894, pp. 82-5. 196 KNOWLEDGE. [Septfmukr, 1901. thrown up by the tide. Two most remarkable members of this group have been found by the Rev. A. E. Eaton on the shores of the far southern island of Kerguelen.J One — Anomalopteryx maritima, Eaton, with narrow strap-like wings, haunts the nests of sea-birds ; while the other, Apetenus liioralU, Eaton, creeps over the stones of the beach. Several small flies of prey belonging to the family Empidae may be found on our coasts, often occun'ing in great companies. Though this family is structurally far removed from the groups mentioned above, the sensitive bristle of the feeler, for rxamjjle, being borne at the tip, not on the edge of the tenninal segment, and the grub possessing a distinct head — Haliday pointed out the likeness to Coelopa in the general aspect of these marine Empids. The most characteristic of them belong to the genus Chersodromia. Perhaps the most note^ worthy species is C. arenaria, Halid. (Fig. 4), in which the wings are so shortened as to be useless for flight — a character, as we have seen, rather frequent among the insects of the sea-shore. Apparently this genus occurs only on our islands and the Scandinavian coasts. Another family represented on the sea-shore whose members live by prey is the Dolichopodidie. These are slender, agile flies, often of bright blue or green metallic colouis ; they are very numerous in species, and often haunt the margins of lakes and streams, running over the surface of the water in pursuit of their prey. Some of the more daring members of this family live close to the edge of the sea within reach of the spray of the breakers, and find their victims in the weaker insects of the shore. Several of the large genera such as Dolichopus and Hydrophorus have each a few maritime representatives, while Machaerium, with only one species — M. maritimce, Halid. — seems to be confined to seaside marshes, and Thinophilus and Aphrosylus (Fig. 5) each with two or three species are only to be Fio. (After Fio. 5. Fio. 0 Aphrosylus raptor. ma\v. M.agiiificd 3 time.'*. Westwood.) Fig. 6.— (inih of Apjirosylus. Maguificd 12 timrs. (.Af oi- Wlipder.) found close to the edge of the wat«r, occurring on rocks and seaweed washed by the waves. The species of Thinophilus arc bronzy in aspect, but the Aphrosyli have the ashy grey hue characteristic of so many sear shore insects. The specific names raptor and ferox, t G. II. Verrall. "Zoology, of Kerguelen Island, Diptera." Thil. Trans. S. Soe., Extra Vol.CLWIII . 1879. ])p. 228-48. bestowed on them by their describer, A. H. Haliday, sufficiently indicate their habits. For many years Aphrosylus was known only on the British, Irish, and Italian shores, but quite recently three species have been discovered on the Pacific coast of North America by Prof. Wheeler, § who was fortunate enough to find the curious gnib of one of them (Fig. 6) among the seaweed covering the rocks. But the most perfectly adapted to marine life of all the flies of the sea-shore are minute in size, and belnng to one of the lowliest families of the order-the Midges or Chironomidw. Though small, these arc among the most familiar of insects; they may often be seen on a summer evening flying in swarms over the waters of ponds and streams in which their grubs live. The best known species of the family, Vhirunnwiix plumriK>i>!. and its burrowing red gi-ub the " blood-worm," together with some allied forms have been lately described in detail by Miall and Hammond. || The Chironomidse are readily to be distinguished from the gnats or mosquitoes (Culicidae) by the great reduction of the jaws, which renders them incapable of biting and by the simplicity of the wing-neuiation. One or two species of Chironomus haunt the rocks exposed at low-tide, and their grubs live in the sea as happily as the gi-ubs of their relations live in fresh water. Prof. Miall has found that the fresh water lai-\'£e cannot long sui-vive transference to salt water. Possibly by gradually increasing the degree of salinity, acciimatisation might be brought about in the lifetime of an individual, but there can be no doubt that in the course of generations these marine midge- grubs have become well-used to their strange suiTound- ings. One of them which has been dredged off our coasts from a depth of 15 fathoms was described in the first instance as a marine annelid under the name of C'ompnnfifi rruriformh. Except in its colour, which is appropriately a light sea-green, this creatiU'e closely resembles an ordinary 'blood-worm," possessing a pair of sucker-feet at either end of its body, and tubular '■ blood-gills " on the two hindmost segments. Mr. Swainson has lately found this grub on hydroids at various parts of the British coast. "i It may perhaps prove to belong not to a Chironomus in the strict sense, but to the closely allied genus Thalassomyia (which possesses but one species, T. Frauenfeldii, Schiner) dis- tinguished by the short, broad, and emarg^nate fourth tarsal segment. On the shores of the Adriatic, this midge was found sitting on rocks within reach of the spray, and it has been noticed on the coast of the Isle of Wight ill a somewhat similar situation resting on the walls of a cave, where the spray constantlv washed over it. Marine midges have been found on the other side of the Atlantic. A grub dredged from the depth of 20 fathoms off the coast of Massachusetts and its parent fly were described by Prof. Packard*" in 1S69 under the name of Cliirnnomiis oceaninis. As might be expected they have not escaped the notice of French naturalist^s. In 1892, Prof. Moniez described a marine Chiionomus from the shores of the Channel remarkable § W. M. Whoi'ler. " A Genus of Maritime I)olic1io]iO(U(lie now to America." Proc. Cat. Aead. Sd. (3) Vol. I ; 1897, ]i|>. U5-152. jil. 4. 11 L. C. Miall & A. R. Hnmiiiontl. "The Struct urr and Life- History of the Harlequin Fly (Chironomus)." OxforJ, 1900. IT See F. V. Theobald. " .\n Account of British Flies," Vol. I. ([ip. 202-;!). Loudon, 1892. ** A. S. Packard. "On Insects inbabitiug Salt Water." Froc. E.'.-.iex Inst. (Salem, Maes.), Vol. VI., 18fi9, pp. 41-51. Septembkb, 1901.] KNOWLEDGE. 197 in tlie £;rees and palps of the second maxillje. can be made out. The eleven- segmented feelers of the male are most characteristic in form ; the head is almost entirely hidden beneath the great hood-like forebody shield, while the hinder end of the insect seems disproportionately large owing to the immense size of the genital cla-spers. This midge is only about 2 mm. long. " I have observed the insects," wrote Haliday, " only in blustery weather, and could not find any trace of the female among them.' She escaped observation indeed for well-nigh forty years; then in 1894 descriptions of her were published almost simultaneously || by M. Rene Chevrel, who had been diligently studying the species along the rocky coEists of Calvados, and the present writer, who met with a colony on the shores of Killiney Bay, Co. Dublin. The female Clunio (Fig. 8) is wingless and degraded — almost worm-like with her +t A. H. Haliday. "Descriptions of the Innects fisured. &c ." yat. Hist. Rev., Vol. II.. 1858 {Proc. of Hoc, p. 62). XX K' Chevrel. " Sur un Diptcre Marin du Genre Clunio." Arch. Zool. Exp Gen. (3) 11., 189i, pp. .58,3-598. ft H. Carpenter. "Clunio marinus, a Marine Chironomid." Enl. Mo. Mng., Vol. XXX., 1894. pp. 120-30. J. J. Kieffer. " Description d'un Diptere sous luariu." Bv.V. Soe. En(. France, 1898, pp. 105-8. elongatAj and (when full of eggs) swollen hind-body, her short and feeble legs, her feelers with only seven reduced segments, and her small eyes. According to M, Chovrel's obsci-vations, Chuiio can only be observed during the low spring tides, " One only begins to see them,' he writes, " when the rocks where they dwell are uncovered. Few in number the lii-st day, tliey abound on the morrow and the two following days. Then, becoming scarcer and scarcer, they disappeai- completely towards the sixth or seventh day, not to be seen again till the next syzygy," Thus periodically they appear from April till October. Tho males aie very active, moving over the rocks and the seaweed — frequenting especially the masses of the bright green Cladophora- or skimming across the surface of tho rock-pools. They ;u-e in search of tho females who creep slowly about among the seaweed. When mating takes place, the male seizes the female with his powerful clampers, holding her by tho last abdominal segment, and carries her away with him, her body being almost in a line with his, and her feet, clear of the surface whereon he is walking, kicking in the air. " lie takes her about thus for an hour, " states M. Chevrel, " then he places her on a rock or an alga. The female, being freed, walks slowly for some minutes, and chooses a suitable spot to lay her eggs. ... She applies the tip of her abdomen to the rock or seaweed and fixes thereto a gelatinous, cylindrical tube wherein the eggs are lodged. " These number from 50 to 120. " When the operation is finished, the female, exhausted by the efforts which she has made, can only move slowly; she walks painfully, stops often, and only regains a little strength after" resting for several minutes; then she wandei-s at random and ends by falling into the water, and, floating on the surface, waits for death, which is never long delayed." Often her feet become caught in the gelatinous substance of her egg-tube; she fails to disengage herself and dies resting on her eggs. " The male who has fertilised her," writes M. Chevrel, with a fine appreciation of this little drama of love and death, '' does not forsake hei- ; he stays near while the o^ggs aro being laid, then, as if he knew his duty as husband or father, lie throws himself upon her to rescue her from the sticky substance, or to carry her with her eggs to a more favourable place for the hatch- ing of the ofispring. Sometimes he falls himself a victim to his devotion and dies beside his mate, taken in the same snare." The shrinkage of the female's body after the eggs have been laid is most remarkable. The degradation of the jaws in both sexes is such as to render feeding impossible, so that Clunio is an excellent example of those insects in which there is a complete division of labour between the larval and perfect stages of the life- history, the former only being concerned with feeding and the latter entirely devoted to reproduction. Tho life of Clunio as a midge is therefore very short. M. Chevrel could find no trace of them after the tide had covered their breeding-places, and doubts whether they survive either by coming to the surface, or by seeking shelter below. But as he was able to keep specimens alive for 36 hours in captivity, it is likely that they survive from one low tide till the next — • especially as a Clunio was discovered in the Adriatic at Trieste among submerged colonies of mussels. The lai-va of Clunio is hatched about a week after the eggs ai-e laid, being then only I mm. long, whitish and partly transparent. Tho full-grown lai-va (Fig. 9) 198 KNOWLEDGE. {Septembee, 1901. is of a briglifc green coloiir, resembling closely that of the Cladopbora, among ^yllicb it lives. Tbe ■well- developed head with strong mandibles working at an angle against the serrated labial plate, is succeeded by twelve body-segments whereof the first and last bear- paired false feet ai'med with circles of booklets. Special breathing organs like the gills of a Chironomus-larva are absent; this giaib evidently breathes the dissolved air over the whole surface of the skin, a method of respiration common among very small aquatic insects. Among the insects found by Mr. Eaton on Kerguelen Island is a female midge which resembles Clunio in some pai-ticulais. The body is elongate and worm-like, and the wings ai'e reduced to small vestiges, but the legs are relatively very long and the hind-body ends in a pointed ovipositor (Fig. 11). This southern Chironomid — Haliryfus amphihiiis is its name — was found " at the verge of the tide, creeping over Enteromorplia and mussels exposed by the recess of the sea. and walking upon the siu-face of puddles and tide-pools. The fly was common upon some small isolated rocks which were always submerged at high water. The adults in that locality must spend a large portion of their lives under water. Probably whenever the water has retired sufficiently from the top of the rocks, all tbe flies huiTy up from below to take an airing." Another tiny marine midge (Fig. 10) has lately been Fi&. 10. Fig. 10. — Eretmoptera Brownii, male. (Alter Kt'llogg.) Fi&. 11. — Haliri/tiis amphibius. female. (After Eaton.) 4 Fig. 11. Magnified 15 times. Magnified 12 times discovered on the rocky coast of California, and named Eretmopfera Bruuni by Prof. Yenion L. Kellogg.§§ On account of its very remarkable structiu-e its describer considers it the type of a distinct family. In both sexes the wings are " narrow and strap-like and wholly without veins . . . not specially thin or delicate, but rather thickened." The hind-wings, instead of being the stalked knob-like " balancei-s " usual among the Diptera, " are minute scale-like pro- cesses appearing like rudiments ' of wings" of the ordinary type. It is possible, therefore, that this midge §§ V. L. Kellogg. " An Extraordinary New Maritime Fly." Biol. Sulletin, Tol. I., 1900, pp. 81-7. may represent a very early stage in the evolution of the Diptera. before the characteristic " balancers " had become specially modified. " The flies, of which there were many, were resting or running on the surface of the ocean water of tide-pools, and had a t.endency to gather in large numbers in patches and in ball-like masses on the water." The discovery of this most remarkable midge shows what wonders of insect life may still await the diligent observer by the sea^shore. Reviewing generally the marine flies here briefly sketched, it will be noticed that they show a strong tendency towai'ds the reduction or total loss of their wings. It will be remembered that a similar tendency is found among the marine beetles, but the flies are such typically aerial insects that loss of flight among them is especially remarkable. In a well-known passage Dr. A R. Wallace||[| has pointed out that the insects inhabiting oceanic islands are often flightless, and he ex- plains this as due to the action of natiu-al selection ; when flying individuals are liable to be blown out to sea, it becomes a positive advantage to the species to lose the power of flight. This state of things seems to be can-ied to an extreme on the far-off wind-swept island of Kerguelen. There can be little doubt that life by the sea^shore is rendered safer for insects, when through loss of the power of flight, they have ceased to expose them- selves to the full power of the wind. And thus the degi'adation which they have undergone is the price of a more perfect adaptation to the strange surroundings which their ancestors chose long ago. ROUND FAIR HEAD. By Grenville A. J. Cole, m.e.i.a., f.g.s. The north-east of Ireland is essentially the land of Scots. From the third to the sixth century, its enter- prising sons went forth, ran their light curraghs into the harboius of North Britain, held their own in that rugged counti-y, and gave their name to Scotland. In the sixteenth centuiy, the MacDonnells of the Isles, thirsting for a wder empire, returned to their ancient homes in the valleys that cut the Antrim plateaux, and sought to establish themselves amongst the Irish, who had almost forgotten the relationship. These Scots, indeed, had to win back the land which their ancestors had forsaken, and they fonn a population between Ballycastle and Cushendall, Scottish and distinct, still presei^ving the old religion, which was common to all at the time of their return. In the midst of their territory rises the promontoi-y of Benmore, Fair Head, as the English have called it, a worthy opponent to the great headland of Kintyre, which faces it foui^teen miles away across the sea. There is no more distinctive feature in the county of Antrim than this sheer cliff-wall, with the rugged talus at its foot, a buttress to the coast, a defiance to the northern storms. From Ballycastle on the west to the woods of Murloiigh Bay upon the east, the great crag dominates the landscape. Its essential characters become best revealed if we approach it from Ballycastle Bay. South of us, on the broad dome of Knocklayd (Cnoc- leithid), we have an epitome of the most momentous phases of the geological history of Co. Antrim. The base of the hill consists of old micaceous schists, rocks nil A. R. Wallace. "Darwinism." 2nd Edition (pp. 105-6). London, 1889. September, 1901.] KNOWLEDGE. 199 that have been squeezed and uptiltod at a vei^ early period. They are contoniporary with the central masses of the Grampians. But above tliem runs a level band of chalk, encircling Knocklayd, with, above that again, up to the summit, 1700 feet above the sea, the brown- black basalts that ai'e so fsuniliar throughout Antrim and the western isles of Scotland. Tlie " white limestone," or chalk, is a relic of the material tJiat once stretched across the country, deposited as fine ooze by the organisms of the Cretaceous sea. The sea-floor was raised by the mysterious and reciu'riug earth-movements ; the chalk became attacked by rain and rivers, and was converted into grassy downs, such as we see to-day in south-east England. Then, in what .are called Eocene times, volcanoes broke out all across the area ; * stream after stream of lava was poui-ed over the blackened downs, filling up the hollows, choking the valleys, and finally burying the older features in continuous sheets of basalt. In our own times, these sheets have given rise to the high plateaux of the north, just as they fonn the tablelands of Trotternish in Skyc and of the west of Mull, inter- sected here and there by ravines and valle3-s, into which their dehria are swept down. Knocklayd is an outlying mass, cut off from the main plateau.x by denudation, and fonns a fitting introduction to the story of Fair Head itself. Wo leave the blown sand that gathers in Ballycastle Bay, and before us rises the long wall of cliffs, cul- minating in the sharply defined crest of Benmore, a columnar fa.9ade erected, as it were, by titans. Yellow and grey sandstones, cut here and there by dykes of basalt, flank our route at first; and then we come unexpectedly on a little coal-mine, bun'owing into the face of the cliff, and bringing out its black heaps against the road. We have here, in fact, the same strata, low down in the Carboniferous system, as those in which coal is successfully worked near Edinburgh. Further on, where the road becomes a mere track, climbing above slopes of grass, we find the yellow sandstone worked in a higli quarry, from which the crane lowers the blocks for shipment at a tremulous pier. It is odd to note here the coal-seams exposed upon the natural surface of the cliff, and showering down their black detritus on the pathway. On our left, across five miles of gleaming water, Rathlin Island smiles in sunlight, its strip of chalk capped by a basalt layer, a mass detached from Antrim by the wash of waters round it. It was my fortune thus to view it on the thii'd of January in the present year, one of those fresh and brilliant days that are far more common in a highland winter than we realise among the fogs of towns. There certainly was nothing to suggest the bitter tragedies of 1575, the slaughter of enfeebled Scots up and down the plateaux, the relentless hunting of women and children through all the white caverns on the shore. And now the path rises further, up the side of a waterfall, which comes leaping down the flank of Sron- bane, a projection perhaps named from its contrast with the sterner mass beyond. The foot-track is for us no longer; we must take to the slopes of grass, and trust to oiu' wits to bring us round. Half-a^mile further, the fii-st blocks of basalt cumber the ground; above us we see the sandstones seamed with horizontal sheets of lava, wliich have worked tlieir way in between them, baking them as they went. These • ffee "Volcanoes of the North," Knowledge, Vol. XXI. (1898) p. -'G6. arc tho offshoots of the great volcanic knot of Fair Head, a huge intrusion of molten matter, now cold and cryst.;illine, which forced its way in among tho older rocks during the eart.h-slorin that, once raged in Antrim. Those who know Stafl'a or tho Giant's Causeway will recognise the volcanic rocks above us now. The sheets have shrunk on cooling, iiavc cracked transversely, and a range of columns results, giving to the cliff-face the likeness of a gigantic organ. We soon see that this columnar structure, becoming more coarse and bold in Benmore itself, is responsible for tlic characteristic sheerness of the mass. The columns break off along the joint-planes, and provide tlie formidable blocks, clean in the side, sharp at the angles, which are added yearly to the talus. And soon this manifold talus threatens us. Ilillierto the sandstones have furnished us with ledges, on which the grass gives foothold ; it has been easy to climb to the base of tho cliff-wall, or to descend to the terraces along the shore. But now, across the rivulet that falls in cascades out of Lough Doo, the streams of stones stretch down seaward, bai-e and continuous, from tho crag. Each has to be crossed with forethought; a gi-assy interlude may or may not lie beyond it; it is certain that another stone-stream will appear to bai- tho way, hidden by the one with which wo are immediately concerned. Some of the individual blocks are large enough to be identified miles away. Thus the pro- jecting masses, heaped on one another below Lough Doo, four or five together, form a group which is descried from Ballycastle. A stout stick without a ferrule, which will not slip when the weight is thrown on it, serves one well amid this scene of desolation. The camera is strapped firmly on the back, the geological hammer is thiaist into the collecting-bag, only to be produced when wanted; for the two hands are here as useful as the feet. A good walker has twice rounded Fair Head in a day, jumping from block to block. For the ordinary person — and he should be one who knows something about taluses — I would say, neither begin to jump, nor hesitate at any point too long. The experience gained on ordinai-y " screes," where one can thrust a long stick against the slope above one, and ascend the more stable blocks as on a staircase, avails one little on Fair Head. The walk is an almost continuous scramble, and it seems a matter of chance whether one succeeds or fails. Two men together should be almost certain to succeed. One man alone may find it more discreet and business- like to fail. Though the whole crag rises only 636 feet above the sea, the sense of gloom, of voiceless walls of rock, of absolute and naked savagery, soon becomes impressive and supreme. The cliff above is unnotched throughout a ban-en mile, a mile that may occupy an expert for an hour, a cautious walker for two or more. Once round the northern angle, the view widens, and Scotland grows clear across the sea. The high masses on Kintyre loom up near at hand ; Islay lies out there to wcstwaid ; and between them, pink with haze, or just caught by a wisp of sunny cloud, we may see the Paps of Jura, and the long ridge stretching up to Lome. A startled gull wheels up ciying fiom IjcIovv us; above us towers the impregnable fortress, steel-grey, gloomy, and impenetrable, the blocks over which we scramble seem rarely less than ten feet long; they ai-e sometimes as large as a cottage, set obliquely or on end. Between them, the interspaces would easily admit 200 KNOWLEDGE. [September, 1901. a, man ; and small chance of succour from Murlough or Ballycastle comes that way. The absence of small stones makes the Fair Head talus in certain places almost gruesome ; the fissures widen out into caverns, which have no true floors, but from which one might slip, down the face of one stone or another, till the earliest and lowest layer of the mighty pile was readied. Fortunately, the sharpness of the edges and the angles prevents movement of the blocks themselves; a rocking stone is scarcely met with, and foothold on the crystalline dolerite is secure. At one point, a huge mass of columns has slid down the cliff-face without serious fracture, and remains 2iropped up against its j)arent, a giant's step to the summit of the wall. Below it is one of the roughest streams of debrix; then again an easier interval, witli tufts of grass and moss, forming bridges that are often serviceable enough. Again and again an ordinary mortal has to let himself down over a joint^face by his arms, to find a foothold on the angle of some lower stone, and then to climb out on the opposite side, like a spirit escaping from a tomb. All this is no doubt exhilarating, but equally laborious ; on this winter's day, despite the superb cleai' leather, I confess that I was content to fail. I had thought of gaining the grassy paths of the old collieries in Murlough Bay, and returning serenely by the Bally- castle road ; but, close against the goal, there runs a deep channel in the talus, with blocks of forbidding bulk upon its southern side. I scrambled up and down, could not see my passage, except into the mysterious and communicating vaults below, and preferred to return over the way already known. The strange character of the talus was demonstrated by the fact that again and again one crosses a piece of broken ground by the same stones or the same gaps that have been selected on the oiitwai'd way. The choice on the return journey is limited by the fact that there is often one passage, and no other. Again I write for the veiy ordinary mortal ,; the talus might seem a Jacob's ladder to a cragsman. The landmarks by which progi-ess can be reported are the great erratic stone on the very edge of the cliff, left there during the ice-age. before the crag was carved back to its present line ; this or that conspicuous block, resting freshly on the apex of a grey stream of its pre- decessors : or some feature of the columns on the wall, such as the point where they are undercut, and actually overhang the base. 'The scale of the rocky landscape is so large that one hails the passage of these points in succession, until the last wedged up and projecting pile comes in sight, close against the streamlet from Lough Doo. Even here, there is a climb down to tbe gi-ass- slope before the gi-im masses are forsaken. And thence it seems gentle enough to Ballycastle. Murlough Bay. if one should reach it by this route, oi- by the legitimate road across the headland, presents beautiful rock-contrasts, even to the untrained eye. The cliff of chalk, high above the wooded combe, rests on rod Triassic strata; these again have a foundation of old crystalline schists. Above the whole, grey in the north-west, the dolerite crag of Benmore ris-es, as a memorial of the volcanic epoch, to which we owe equally tho high ridge of Slemish, and the mosaic pavement of the Giant's Causeway. Along this coast, the form of Fair Head perpetually haunts us; some artist should record it m a hundred aspects, as Hokusai painted Fujiyama. THE RINGED PLAINS OF THE MARE NUBIUM. By E. Walter M.vundek, f.u.a.s. The accompanying photograph was taken by MM. Lcewy and Puiseux at the Paris Obsei-vatory on 1896, September 29. A portion of this same region — the western shores of the Mare Hnmorum — was giveii in the December number of Knowledge for 1899, under the title of " Hippalus and its Siuroundings," and was ail enlargement from a photograph taken at the same observatoi-y on 1896, April 23. In the earlier paper, attention was chiefly drawn to the deep clefts in the mountainous region west of the Mare Humonim, which follow the outline of the sea itself ; to the bold ridges in the sea, which are roughly jiaiallel to both the clefts ; to the border of the Mnre, and to the ramparts — broken down or completely submerged on the seaward side — of the walled plains that are set round the Mare Ilumorum. The present plate covers a much wider area. Stretching along its south is a very mountainous and disturbed i-egion, where great ringed plains and rough congeries of unsliapen hills seem at some early dat« to have striven together for supremacj', and where both, indifferently, ai-e now pockmarked by the small deep craters of later convulsions.. Hainzel is half out of the picture. Heinsius, almost eaten up by its three parasitic craters, is on the border to the west. The giant triplet of Pitatus. Gauricus and Wurzelbauer are almost on the terminator, and Capuanus, Ranisden, Mercator and Campanus lie in the southern centre. To the east and north-east are the Mare Humoriun and the Oceanus Procellarum. The first is not well seen on this photograph owing to the conditions of the exposure and development, but the huge walled plain, Gassendi, on its northern shore, is very well shown, and the highlands which extend from it to the borders of the ruined plain Letronne. - The whole centre of the photograph isxoccupied by the Sea of Clouds,-, and its floor jJi'esents a study of walled and ringed plains, in all states of preservation and decay. Bullialdus. the gi-eatest and deepest of those on the floor of the sea. seems also to be of the most recent date, and from its south-west, border there comes a curved chain of four craters, Bulliildus A. B. C, and Agatharchides A, t.he largest craters in the Matf. To the north, Liibiniezky is evidently much more antique, and its ramparts are weathered to a smooth round cui-ve ; its floor is flattened to a dead level, and neither Schrbter, Miidler nor Schmidt ha.ve been able ever to detect any irregularities upon it. In the photo- graph, the wall has a distinctly horse-shoe aj)i5earancc with the opening to the south-west, but Neisoii draws a continuous ring, as distinct, on the south-west as on the north-east. Close examination of the photograph .shows that the wall is continued right round, fovu- buttresses apparently blocking the entrance to the horse-shoe. In a much worse state of "Jjreservation is Fra Maiiro, which lies further to the north-west and almost on the terminator. At some places its wall is very much defaced, in others quite broken down. In its eastern border, there is a deep irregular depression which is continued towards the north through the highlands and the low-lying counti-y beyond, as far as to the east of Gambart A ; and cutting the ringed plain of Fra Mauro in two and passing through its central craterlet, is a veiy delicate; and line rill which Ncison traces from the Knoiileil, •dnr 1:="% <», ^■ .i^< 1 NORTH, THE RINGED PLAINS OF THE MARE NUBIUM. From a PlLctcgi-apli taken 1896, Si'plriiibi.-r 2'J. Ki-Uli. l'ari> Mean Time, with tlif Liivat Kquatorial Coiule of tlu- Paris Observatory. Scak' :— Diamotui- of JIooii, 2'i inolies. Moou's Ago, 22d. Ulli. SEPTIi>r8tB, 1901.1 KNOWLEDGE. 201 mount-ainous district, to the uorth, tlirough the plain, ;uid along the lloor on the base of the eastern rajnpart of P.u•l•^•. and skirting the eastern tlank of the orater Parry A. Tliere ai'e several of these vcrv delicate rills seen on the photograph. They usually appear cleaving the tloor of one of the ancient walled plains. One still finer than that crossing Fra Mauro, traverses Letronne from north to south, and seems to end in the highland country lying between Letronne and Gassendi. Another and verv remarkable one, not mentJoned by Neison, cuts Gassendi itself right across from east to west. It seems to mai-k the limit which the Mare Huniorum would have reached had not the ramparts of Gassendi been already there, and it is a continuation as a rill of the mountain ridije that fomis the eastern border of the Mare, and that joins the rampart of Gassendi immediately to the south of the triangular ridge, Gassendi H. This eastern border of the Mare Hiunoinim Heinsius (^1 ainiiryV) J{ *Clausius GauricosV.^ yj>cLl^l,(S) C® \i^ '5Ramsden ^ ^ Cichus Key Map of Plate. is itself a remarkable object. It is evidently comple- mentary to the three deep parallel clefts on the western banks of the sea, but in its northern part it is decidedly a ridge ; in its southern, where it passes through Doppelmayer g, its nature is doubtful, for Neison calls it a '■ rill " there, and Loewy and Puiseux term it a ■' terrasse." About half-way between Bullialdus and Guerikc, and slightly inclined to the meridian, is seen a chain of three or more ringed plains far advanced in ruin. At least the photograph presents them almost unmistak- ably as ringed plains, but Neison in his " Moon ' figures only the most northern member of the chain as such, not perceiving the western or separating walls of the more southern. At the north-east and south-west corners of the central plain, where it cuts the cuter members of the chain, are two craters of comparatively recent origin, and a straight rill unites the two and is tangential to their north-western Hanks. We seem here to see the cause of the ruin and semi-obliteration of the ringed plains in tiie conjunction of rill and crater, both signs of weakness in the lunar crust, and causing subsidence on one side and upheaval on another. Due east of the triplet of walled plains. Fra Mauro, Parry and Bonpland, and about half-way between "them and Wichniann, lies a curved and continuous range of hills, the Riphaen Mountains. The ciuve of these hills appears on the photograph to be continued towards the west and then round to the .south by a scries of isolated peaks, and the central lloor is smooth and unbroken save for a pair of very small craters, so that the impression is given that here we have the remnants of a huge walled plain, many times larger than Gassendi, whose ramparts are still intact on the east, much broken towards the north and west, and entirely submerged towards the south. Still another instance the photograph seems to give of a walled plain that has now become not only partially but entirely submerged. To the south-east of the Riphaen Mountains are two craters, llerigonius B and C ; and round C, the more southern of these, is seen a broad circular dark marking that looks like the wall of an ancient plain that has been not only levelled, but even depiessed below the surrounding surface by the action of the great central volcano. The most perfect and stable in appearance of all the walled plains seen on the photograph is Gassendi. Tlie north-east corner shows a marking on the floor which forms a curious copy of the shape of Ga.ssendi itself with its gi-eat parasite ringed plain, Gassendi A, hang- ing on its northern border. Two other curious markings ai-e seen, triangular in shape. One is the deep right-angled triangle that, is stamped on the northern spur of the Riphaen Mountains, the other is a deep triangular impression in the mountainous region to the south of Cichus A. THE GREAT SOUTHERN COMET (1901 I). By W. F. Denning, k.r.a.s. The brilliant comet vifhich suddenly appeared in the morning sky on AjDi-il 24 incited widespi'ead obsci-vation and comment from southern observers. The merit attaching to its first discovery apparently rests with Mr. Arthur Hills, of Queenstown. The object, apart from its conspicuous and almost startling aspect, formed a view, veiy picturesque of its kind, in the Iwilr^'ht ovta- the eastern horizon. It exhibited a short, brilliant and almost vertical tail with a dark rift running lengthwise along its central part, and during May there was a long filmy streamer, or faint secondary tail, directed to the south and inclined at an angle of about 35° to the brighter tail. Major Eddie, who obtained some magnificent views of the comet at Naauwpoort, S. Africa, says that on May 6 " the bright straight tail with its faint extension was about 16° long, reaching nearly to Rigel, while the enormous lateral emission of shimmer- ing light flooded the S.W. sky with a ghostly gleam 40° long, 6° to 10° broad ; while the whole space between this mighty extension and the more brilliant tail was filled with a gauze-like sheen." (/i. A. A. Journtil, June, 1901.) Several of the observers may bo said to have dis- covered the comet for themselves, for they had no intimation of the presence of the brilliant visitor until they saw it shining in the sky. When it was first 202 KNOWLEDGE [September. 1901. noticed it was situated to the S.W. of the sun, and in perihelion; a few days aftei^wards it passed about 15° south of the sun, and became visible in the evening sky. The faint broad stream of luminous material which formed the secondary tail was curved near its southern extremity, and it remained visible, under various modifications, from May 2 to 27. It may be interesting to summarize the estimated lengtbs of the two tails, as given by several observers: — May 6 „' 12 H ii-n IT) f) 6 2 ■A 4 5 0 s 111 11 U m Bright Tail. 10 111-12 => 5 8 10 5-10 Seeouilary Tiiil. 30 2.3 2'y.M 20 23 2 5 -SO 2.5 — 10 — 12 12 20 16 40 — 40 12-U . 25-30 16 — 18 20 . . 30-35 15 25 U. T. A. Imies, Cape Town. J. Lunt, Cape Town. J. T. Bird, Dullstroom. E. Transvaal. C. J. TaUor, Cape Town. A. M. Megginsou, SvdneT. C. J. Merfield, Sydney. L. A. Kddie. Naauwponrt, S. Afriea. The comet remained prominently visible to the naked cyo until about May 27, after which moonlight practically obliterated it, but Major Eddie watched it in a field-glass until June 10, when it appeared as a faint nebxilous streak. {B. A. A. Journal, June, 1901.) A large number of descriptions and drawings of the comet have been received from S. Africa, Australia, and other regions, and a number of these have been published in the scientific journals. A series of sketches were made by Mr. C. J. Taylor, of Cape Town, and these show the general aspect and approximate positions of the object very well. Possibly, however, the angle between the bright main tail and the faint long streamer is not represented suificiently great, as photogi-aphic views of the comet show the inclination to have been about 32° on May 6 and 7. Mr. Taylor, wi-iting on May 28, from Kenilworth, Cape Town, says: — "On the morning of April 27, I caught a glimpse of the comet, but it was too near the sun to be observed with advantage. On May 3 it was observed directly after sunset, and was a very con- spicuous object on the 4th, when the tail was over 4° in length and divided in the middle by a clear dark space, the preceding portion being much wider and more defined than the following. A shorter secondary tail, very indistinct, was to be observed in the telescope sweeping to the east. The comet became a splendid object thereafter and was seen to the greatest advantage between the 6th and 15th, the best views being obtained on the 9th and 11th, when the main tail extended over 8 to 10°, still being clearly divided ; while the secondary and fainter tail made a graceful sweep over fully 20° Soiitli. Nortt. Flo. 1.— Tlie Great Soutliern Couiet (1001 I.). From sketelie« by Mr. C. J. Taylor. Skptembek, 1901."! KNOWLEDGE 203 aiul ciimKI 1)0 tr;KvJ tn ft and a in Lcpus*. Tho liciid was Yoi"\' bright and about equal in diamotcr to Mars at present. Ou the 15th the fainter t the first few months of its opening year with its brilliant star and its great comet. Hcttcrs. [The Editors do uot hold themselves responsible for the opiuious or statements of correspondents.] NOVA PERSEI. TO THE EDITORS OF KNOWLEDGE. Sirs, — With reference to the photographs of the Nova Persei region in the July number of Knowledge, my attention has been kindly called independently by two of your readers, Mr. ,T. E. Davidson and Mr. J. E. Gore, to what is apjjarently a bright star visible on the photo- graph of Feb. 28, but absent from that of Feb. 20. It will be readily found at a short distance south-east of the bright star 36 Pei^sei, visible near the upper (north) part of the, photograph. Reference to the original negative shows, however, that this object is not the image of a real star, but is due to a spot on the film ; and it is absent from another photograph taken upon the same night. Now that Perseus is coming round into a favourable and convenient position for evening observation, no doubt many observers will contemplate looking up the Nova, and hence it may be of interest to state that the star is still a fairly bright object. On several occasions lately it has appeared between 6 and dh magnitude ; and on the nights of the 9th and 10th August, it was plainly visible in an opera-gla.ss. The intense red colour formerly characterising the object seems, however, to have almost entirely disappeared, A, Stanley Williams. Brighton, 1901, Aua. 12, DOUBLK KAJNMOW. TO THE EUlTOHb OF KNOWLKDCL Sirs, — Whilst staying at the Goschenen Alp in July last a thunder-stoiin accompanied by heavy rain passed overhead one afternoon about 5 o'clock. It was not of long duration, and the sun soon shone out brightly from below the western margin of the storm clouds, whilst the rain was still falling copiously at the eastern end of the valley. On this rain a double rainbow of con- siderable brilliancy was produced and ])crsis(cd for ,')-10 minutes. Not remembering to have seen a similar phenomenon, I venture to mention it to the readers of Knowledge and to ask for some suggestion as to the probable cause. This was not an ordinary case of a primary and secondai-y rainbow where the secondary is seen high above the primary and with the sequence of tho coloui-s reversed, but there were two rainbows immediately one within the other, both equally bright and broad and the colours in each following the same order as in that of a primaiy bow — the red of the inner bow and the violet of the outer being apparently in contact as closely as the other bands of colour usually are seen. It occurred to me that there might possibly have been two showers falling at the same time with a dry interval between, and that I had seen a rainbow upon each at such an angle as to exhibit one in apparent contact with the other, but of this I cannot be sure. The rain as it passed over me was a continuous shower, and the length of the clear open portion of the valley down which the storm drifted was not much more than a mile. R. T. Lewis. Ealing, W^., 1901, August 2. [The double rainbow, to which reference is made in the above letter, was probably an ordinary primary bow with a bright supernumerary bow adjacent to it on the interior edge. The appearance cannot be explained in the manner suggested by Mr. Lewis, nor by any simple geometiical theory. Supernumerary bows, of which several are sometimes seen on the inner edge of the primary bow, and occasionally on the outer edge of the secondary bow, are due to the interference of light, and the angular distances between them and the principal bow depend upon the diameters of the raindrops. A full investigation of the phenomena will be found in Preston's "Theory of Light," Ai't. 301. Some interest- ing correspondence on the subject appeared in Knowledge for December, 1900, and Februai-y, 1901. — Ed.s.] BKlTfSfi h ORNiTHOLOCrCAD^^' Condueted by Harry F. Witherby, f.z.s., m.b o.u. Blve-Tits Nestim; i.x a Pu.mf.-A pair of Blue-Tits have for several years built about 15 inches down the inside of a pump here. Each time the handle is raised — and the pump is in constant use — the machinery works up through the nest without in the least dis- turbing the birds. The parent birds enter the pump by an aperture above the handle and leave it by one below. — William Charles Tetley, Aspley Guise, Beds. Red-throated Pipit (AntJius cervinus) in Ireland {Zoologist, July, 1901, pp. 264-267).— Mr. F. Coburn records that he obtained in Co. Mayo on May 26, 1895, Skptember, 1901.] KNOWLEDGE. 205 a male spcciuicu of this bird. ;ind that on August 9, 1S9S, Mr. H. Elliott Howard obtained a further specimen in Co. Donegal. It is a pity that the occurreuees were not recorded before, but Mr. Coburn gives bis reasons at some length for having omitted to do so. The skins have now boon identified by Mr. Aplin, and the occurrence, evidently on migration, of the Rcd-throatod Pipit in Ireland may be taken as authentic. The bird has seldom been observed in Great Brit.a.in, and never before in Ireland. That this pipit is so rax-c a visitor to the British Islands as the records signify is, however, doubtful, since the bird has a wide breeding range in the fai" north and pushes its migrations in winter to Southern China,_ India, Persia, and the Nile. Although the normal lines of its migrations do not probably reach westwards of Heligo- land, so small a bird undertaking such long journeys must often stray slightly from its course and reach Great Brita.iu. where its great resemblance to the Meadow Pipit has undoubtedly caused it to be overlooked. The Occurrence of the Black Kite (Milvus migrans) AT Aberdeen. — Although a regular summer visitor to many pai-ts of the Continent at no great distance- from om* coasts, the Black Kite has only once hitherto been observed in the British Islands. This specimen, recorded bv the late Mr. John Hancock, as far back as 1867, was taken in Northumberland.. Mr. George Sim now records that a male bird of the Black Kite was shot near the City of Aberdeen on April 16, 1901. (Annah of Scott. Nat. Hisf., July, 1901, p. 133.) That the bird has not visited this country more often is remarkable because, unlike the Red Kite, which was once so common a resident in England, the Black Kite, as its specific name miijrans implies, is a migratory species. Coues Redpoll (Linota rostrata) in Barra, Oiifir Hebrides (Annals of Scoff. Naf. Hist , Juli/, 1901, pp. 131-133).— A 8t\idy of the various races or sub-species of the Mealy Redpoll would be of interest and value to every British ornitliuk>;i;ist in assisting to dis- cover the origin of tlie Mealy KedpoUs which visit our islands. Mr. W. Eagle Clarke has lately obtained some specimens of the Mealy Bed]X)]I fiom Mr. W. L. Macg llivray in Barra These birds Mr. Clarke proclaims to be of the Greenland form originally described by Dr. Coues as JEgiothtts rostratus. Dr. Steyneger. who?e con- clusions regarding the Mealy Kedpolls are now generally accepted. gave this race sub-specific i"auk under the title of Acanthis ' linaria ro»trata. Mr. Clarke prefers to employ the more usual generic name Linola. and to call the bird Linota rostrata. In any case whatever name is used, the fonu is a well-marked one, and is a native of Greenland and Xorth-casteni JS'orth America. Its occurrence in Barra is of great interest, since it has never before been detected in Great Britain, although it has occurred as a rare straggler on the west coast of Ireland. Wigeon Breeding in Ireland {Zoologist, July, IIMII, )> 209). — Although the Wigeon ha* long been su>p(cted of breeding in Ireland, its nest and eggs have not hitherto been discovered tliere. Mr. John Cottney now records the finding of several nests and eggs in Co. Down. Mr. Ussher, the well-known Irish ornithologist, has identi- fied both the eggs and the birds' down a? those of genuine Wigeon. Surely it is an ■'injustice" tliat this record, as well as that of the Kfd-throatromi>cd, to his admittedly incomplete work, "The Birds of Surrey," publ^^h£d in lUOll. Bird-migration in the Rlinera. — Under the title "On the Ornilhu- logy of the Var and the adjacent Districts,' Mr. J. H. Ourney pub- lishes an article in the Ihis for July. I'JOl, which will be of consider- able interest to students of the migratory movements of Dritish birds. Ivory Gull in Northamptonsliire {Ibis, July, 1901, ]i. 517).- Mr. O. V. Aplin writes to the Ibis that an immature speciuu'n of th(^ Ivory Gull {Paguphila eburuea)—ii truly Arctic Gull and an occa- sional straggler to Great Britain — was shot at VV'estou-by-Wccdon, Northamptonshire, on February 7th, 1901. ■Little Bustard in Derbyshire {Zoologist, July, 190l, p. 270).- Mr. W. Storrs Fox records th.'it a female specimen of the Little Bustard — an occasional visitor to the British Isles, and usually oci'urriug in the colder months and in the southern and eastern counties -was shot by a farmer near Voulgreave, in Derbyshire, on May 14tli, 1901. Beport on the Movements and Occurrence of Birds in Scotland during I'JOO. Bv 'V. G. Laidlaw, M.B.O.U. {Annals of Scott. Nat. Jlist.', A\m\ and July, 1901, pp. 07-79 and 134-145). -Mr. Laidlaw's annual contribution on this subject to our contemporary will be found of much value to students of migration. All contributions to the column, either in the way of notes or p/wtor/rajih.f, should be forwarded to Hakry F. Wituerby, at 10, St. (Icrnums Place, Btackheath, Kent. ^otittn of ISoolts. " An.vlwl Report ok the Siiithsonian Institutiov iok thi; Ye.ui ending June 30th, 1898." Pp. Ivi., 713. (Washington ; Government Printing Office. 1899.) Illustrated.— Though th.: Smithsonian Report docs not reach British periodicals until som^- years after the datt; to which it refers, it is always welcome on account of the collection of scientiti.c papers given in tlie appendix to it. Only one hundred pages of the present repoit are concerned with "tht: afi'airs of the ISmithsonian Institution; the remaining pages are taken up with rei)rints and translations of important pajjer.s on scientific subjects pubhshed in 1898 in various periodicals. These papers are accompanied liy numerous i)late.s and te-\t illustration.s, and they give a com- prehensive view of scientific thought and expression in the year covered by the report. All matters of wide scientific importance form, at one time or another, the subjects of dis- courses or semi-popular descriptions by leaders of science, hence it is possible to refer to the Smithsonian Reports for authoritative stateuionts on almost every subject which has engaged the atten- tion of the scientific world. The translations will be of exceptional value to students who do not read foreign languages with facility. " Papers on Mechanical and Physical Subjects. " By Prof, Osboi-no Reynolds, e.h.s. Vol. II. Illustrated. (Cambridge : University Press. 1901.) 21s. net. — By the publication of the ))apers in this and the previous volume, the Cambridge University Press is exercising its proper functions. The collectetl papers of men whose ccmtributions to the advancement, of know- ledge are of ]iermanent value may not appeal to a large public, yet greiit service is done to pres^'nt and future investigators when the papers are brought, together in a form convenient for reference. Prof. Osborne Reynolds's ]>apers belong very decidedly to the scientific litt'rature deserving preservation. The earlier volume included forty papers, and the present one brings the number up to sixty-seven, the years in which the papers appeared extending from 1881 to 1899. It is impossible here to describe the many subjects dealt with in these j).apers, but we can give reasons for our appreciatiim of them. In the first place, Prof. Osborne has a style of composition which many scientific men would do well to emulate. He does not write for children, or preach down to an uninitiated public, but practically every- thing he describes is presented in the simplest terms that the subject will permit. Another sign of Prof. Reynolds's genius is that subjects which he took up years ago have suggested 206 KNOWLEDGE. [September, 1901. lines of work t1est teiins. the problem which Mr. Sutherland sets himsilf to .solvi'. liut. unfortunatelv for the correctness of their results, there is a disturbing factor in the computation, which these prophets are apt to ignore. In passing from the known to the unknown in a diagnosis of the future it is beyond human power to allow for the un- expected, yet the unforeseen discovery has taken the mo,st important part in nineteenth century advances. The most far- seeing man of science, with an unequalled endowment in the way of scientific imagination, trying in 1801 to probe the mysterie.s of the future could not have foreseen, for instance, even " through a glass darkly," the development of spectrum analysis in astronomy. So that the prophet is doomed to iiartial failure. There is, however, much usefid work left for him, and this possible task of indicating the probable direction of the earlier improvements of the twentieth century has been attempted with much skill and considerable success by Mr. Sutherland. From the point of view of an ordinary cultured reader, with no knowledge of a technical kind, the author has indulged, perhaps, too much in detail, especially in the first two or three chapters, in which the sources and storage of natural and artificial power are examined. In some other sections, on the other hand, data are provided sufficient for the justifi- cation of several delightful glimpses of, to name an example or two, life at sea and the home circle in fifty years' time. His intimate knowledge of the inventions and discoveries of the last century has enabled the author to produce an entertaining book which should soon have a large number of interested readers. " The Microscope and its Revel.\tions." Eighth Edition. (Carpenter.) Edited by the Rev. W. H. Dallinger, D.sc, D.C.L., LL.D., E.R.s., etc. "817 illustrations in the text, 23 plates, 1136 pages. 8vo, cloth, 28s. ; half calf, 32s. (J. & A. Churchill.) — The appearance of a new edition of this standard work on the microscope and its many branches is particularly welcome, for it enables a comprehensive survey to be made of the progress that has been effected during the last few years in both optical and mechanical departments, and indicates the pressure that modern research has brought to bear on manu- facturers, causing them to do their utmost to satisfy the needs of workers. In a former .edition of this work — the seventh — the editor, the Rev. W. H. Dallinger, condemned in no uncertain language, the microscope known as the Continental Model ; and laid down broad but sensible lines for the building of the stand that was to meet the demands of the various workers of the future. It was in that edition also that a strong plea was urged on behalf of the condensers having large aplanatic apertures and for increased accuracy in manipulation generally. A reference to the new edition of the Work shows how accurate were the author's opiinions and recommendations, and they were un- doubtedly no inconsiderable factor in the general improvement that has" since taken place in the design, and accuracy of action, of the best microscopes of to-day. This is revealed in the pages of the new volume, for many of the microscopes therein figured and described as types have been designed since the last edition was publi.shed, and owe their origin in some measure to the strong expressicuis of opinion then made. The present volume gives a clear exposition of knowledge and theory regarding the microscope ; and although much of the text is to be found in the former edition, there are many new and re-written portions which add to the value and lucidity of the book. The reviews of the products of the various opticians are generous and fair, and will bo found useful to those who need advice in the choice of apparatus. It is a matter for regret that the publishers have not seen their way to issue the book in two volumes — one devoted to the microscope and its optical fittings, and the other to the various branches of research with which it is associated. Many workers woidd require only the first part, while the second would appeal to general readers as niucli as to microscopists. In its present form it is rather a bulky book, especially for those who arc resident abroad or travel with their microscopes. A little error concerning cover glasses has been perpetuated in the new volume, page 439. Not only are the thicknesses given for the three grades of cover glasses less than can be regularly obtained, but the thinnest covers are universally known as No. 1, the medium ;u> No. 2, and the thick as No. 3, whereiis the reverse order is there given. Also the price of a s in. .82 N.A. objective on page 574 given as £5 should be 50s. The book is well printed, the illustrations carefully prepared and well dis- played, and the book is one that will be found invaluable as a text book to all microscopists. "Disease in Plants." By H. Marshall Ward, .sen., f.r.s., etc. (Macmillan.) 7s. 6d. — Prof. Marshall Ward has given us a useful and practical study of the general life of plants, and the causes and effects of the various forms of disease to which they are subject. The book is written essentially with the view of helping the cultivator — whether forester, vine-grower, or grower of roofs or cereals — to understand the general facts of plant-life, the relation of plants to their environment, a.nd the nature and symptoms of the various maladies to which they Skpibmbek, li)01.] KNOWLEDGE. 207 are subject, thus forming an introduoimn to more special studies of the dise;ises and their reaiiedies. Particular emphasis is laid on the necessity of trealini; the living plant itself as the central ligure, and all the circumstances of its environment as subsidiary though indisjK-nsalile subji'cts of stuily. The earlier portion of the work is devotvd to plant physiology, which is treated historically, and to plant chemistry. The important subject of nmts and root-hairs is treated at some length, with a chapter on the characters of soils, and on the leading factors of hybridi- sation .■Mid selection. The second and larger jiart of the book is devoted to the subject of disea.ses. and in it.s turn opens with an interesting brief review of the history of the subject. As to the causes of disease, stress is laid on the fact that very complex problems are involved, and that no one factor works alone either in health or disease, and that a full study of all attenditnt conditions alone can in most cases lead to useful conclusions. The various forms of disease are then brietly gone through. In the final chapter tho author returns to the general consideration of plant life. The book will furnish a very useful intnxiuction to the study of plant disease, and is so written that it can be read with interest by the lar^e circle of plant growers who do not profess any special scientihc knowledge. "Thi MKntTF.RRAXEAN R.\CE : A Study of the Origin of European Peoples." By G. Sergi, Professor of Anthropology in the University of Rome. Illustrat<;d. pp. 320. (Loudon : Walter Scott, Paternoster Square.) 1901. — Students of ethnology will welcome this work, the latest volume of the C'ontemjxirary Science Series as a valuable contribution to our knowledge of the origin of primitive European civilizations. Professor Sergi's well-known researches have already been publi.shed in Italy in 1895, and in (iermany in 1897. In the Knglish edition now before us the author iias carefuUv revised the results of his earlier works, and has added to tliem some valuable data bearing on the origin of the Xeolithic races of these islands. The work h;us inany excellent feature's. The facts are well marshalled, the exposition of current views on the subject are simple and direct, and the problems are clearly and cogently stated. In the opening chapters the theories in vogue relating to the various phases of Indo Gemianism are dealt with. These are stated impartially, but each is finally subjected to a de- structive analysis. The author attacks, in particular, the orthodox theories relating to the ancient conception of an Aryan civili- zation, and concludes by proving that the Neolithic races of Europe originated in Africa, and that the Mediterranean basin was the great centre whence the African migrants reached the centre and north of Europe. The main argument of the book is that from the great African stock, which he calls Eurafrican, originated the three varieties of people who inhabit Europe and Africa at the present day, viz., the African variety, the Mediterranean variety and the Nordic or North European variety. He does not dispute the Aryan invasion of Europe, but con- tends that the Aryan invaders were savages, and that they destroyed the superior civilization which the Eurafrican peo])les had introduced. From this the conclusion is drawn that the Greco-I.«itin civilization is not Aryan, as is commonly sujjposed, but that it was a product of the Mediterranean species of the Eurafrican stock. The additions that have been recently been made to our knowledge of the subject by archeological research in Cyprus, Sardinia, and Sicily do not," in our opinion, receive that atten- tion at the hands of the author which their importance merits. The interesting discoveries that have been made during recent years in the Maltese Islands might, too, have received some mention. These islands have played a most important part in the migrations of the prehistoric Mediterranean races to and from Europe and Africa, and much valuable evidence of this has been forthcoming from the caves and later Pleistocene deposits of both Malta and Gozo. The megalithic ruins, too. of Hagiar Chem and Mnaidra, and the rock tombs that honey- comb the hillsides of the islands, are probably without rival in the Mediterranean, both for their admirable state of pre- servation and for the unique collection of specimens of prehistoric art and of human remains that have been found within them. Several chapters are devoted to the migrations of the Eur- african peoples and to their struggles with the Eurasiatic races of whom the Aryans constituted a variety. From the racial mingling which followed, the language-s of the Eurafrican and the Eurasiatic became more or less transformed, and to this the author attributes the changes in -the language of Italy, Greece. _and elsewhere, and the introduction of the Aryan element which is found in the Neo-Celtic of Wales. The last chapter deals with the evolution of Mediterranean civilization, as showTi by the architecture of the tombs and the culture, language and writine of the peoples of the area. The book contains much that is both novel and suggestive, and it is decidedly to be recommended BOOKS RECEIVED. Historii of Etiijlixh Literature. By A, Hamilton TliompTOii, n.A. (Miirniv. ) 7s. lid. Bird Walrhiif] (Iladdon Hall Libmi-y). By Edimiml Scions. (Dent.) lUiisf rated. Tex-t-liook- of Astronomii. By George C. Coni'^tock. (Ilii-selifeld Brothers.) Illustrated. Ts. fid. net. Thermal Measurement of Energii. By E. IF. (Irillillis, M.\ , F.B.s. (Cambridge : I'niversity Press.) :is. Was Alfred Kin;/ of Englan/I ' Ity X. Snxoii. (Harrison and Sons.) 2s. 6d. The Photo-Miniature. June. I'.lJl. (Dawlmrn & Wanl.) M. Oexso ll'ori-. By Matthew \\'cbb. (l)awharn & Ward.) Pd. Terrestrial Magnetism and Atmospheric Electririt;/. .July, 1901. (Wesley.) 75 cents. Conference Aslrophotographique Internationale, Juli/. 1900. (Paris ; Gaiithier-Villars.) Reports on the Administration of Hhode.iia, Isljs-lilOO. (Tlie British South .Africa Co.) Iri.ih Topographical Jiotan;/. By R. Lloyd Praeger. n A., Ti.E., M.B.I. A. (Dublin : The Acadeniv House.) lOs. 6d. '-♦ ELEANOR A. ORMEROD. Britisii economic science has suffered a loss, in-e- parablc for many years at least, by the death of Miss E. A. Ormerod, whose studies of insects in their relation to the work of the farmer, the forester, and the gardener, had brought her a world-wide reputation. She was born on May 11th, 1828, at SedburV; Gloucester- shire, a daughter of Dr. Geo. Ormerod. known in his day as historian of Cheshire. Living a quiet country life at Sedbury, afc Tildesley, at Isleworth, and finally at St. Albans, she constantly occupied herself with observations on plants and insects, and following in the footsteps of Curtis, Westwood, and Riley, came to occupy an unique position as an authority on economic entomology. Her advice, freely given to practical men all over the country, involved her in a laborious corre- spondence, and the information thus elicited was incor- porated in her '' Reports on Observations of Injurious Insects, " which, commencing in 1877, were issued yearly until 1900. An intimation in last year's Report that failing health would prevent the issue of any more, has been followed all too soon by her death, which took place on July 19th afc her home in St. Albans. In addition to the Reports she published several valuable books, including " A Manual of Injurious Insects." " A Text^book of Agricultural Entomology," and " A Hand- book of Insects Injurious to Orchard and Bush Fruits." Her life-work was greatly helped by her elder sister. Georgiana, whose death in 1896 she felt deeply. For several years she acted as Consulting Entomologist to the Royal Agricultui'al Society, and she was examiner in agricultiU'al entomology to Edinburgh University, of which she was the first-made female LL.D.. an honour only conferred a year before her death. Miss Onncrod won the confidence of farmers and gardenei-s both by the painstaking thoroughness of her work and by the business-like nature of her suggestions. Herself a skilful gardener, she never lost sight of the question whether a certain remedy would be practicable and profitable if employed on a large scale. Henco as an exponent of applied science she succeeded better than others whose scientific training and methods may have been more modern than her own. Her caution is well shown by her reluctance to follow American practice in recommending such powerful poisons as copper arsenite or carbon bisulphide as insec<>killers. She has well served her day and generation. May her work be can'ied on by those whom she has so gcnerouslj' cheered and encouraged by advice and example. — G. H. C. 208 KNOWLEDGE. [September. 1901. Sir CUTHBERT E. PEEK, bart., m.a., f.s.a., etc. lb is with deep regret that w© have to record the death of so liberal a patron of science as Sir Cuthbert Peck, who died at Brighton on July 6th. He was the only child of Sir Henry, the first Baronet; was born in 1855, and married in 1884 the Hon. Augusta Louisa Brodrick, daughter of the eiglith Viscount Midleton, and only succeeded his father m 1898. He was educated" at Eton and Pembroke College, Cambridge, was J.P. for Devon, Middlesex, and London. From early years he was interested in many branches of science and distinguished himself as an active worker in astronomy and meteorology, was a fellow of the Royal Astronomical, Geographical, and Meteorological Societies, of the Society of Antiquaries and of the Anthropological Institute, and served on various councils of tJie learned societies. He went to Australia in 1882 to obsei-ve the transit of Venus, and on his return he drew up the plans for the Rousdon Obser- vatory neaa- Lyme Regis, South Devon, which was built in 1884. Part of his equipment was a 6.4 Merz equatorial telescope, which has been in use since 1885, in his well-known study of long period variable stars. From the obsei-vatory, Greenwich mean time was furnished to the district. In addition to astronomical work, lie also devoted himself to meteorology, and the annual rejjorts from the observatory were rich in scientiiio infomiation. In addition to the usual meteorological observations, he made somewhat of a speciality of instrimients connected with rainfall and wind velocities, having a registering pluviometer and evaporation tanks, whilst a latticed tower for carrying the anemometers is a conspicuous object of the iieighboui'hood. Some years agO' lie conducted a series of experiments for the purpose of determining the factor for getting the true wind velocity from the Robinson cup anemometer, and eventually adopted the Dines pressure-tube instniment as the standard. It was with this latter instrument that he recorded the highest wind velocity ever registered in England during a gale in 1897. Sir Cuthbert was not so keen an ornithologist as his father, but nevertheless he had kept in a good state of preservation the collection of British birds that Sir Henry had made ; whilst a never-failing source of interest to the visitor at Rousdon was the ethnographical museum which he had formed. Science indeed is bereaved by the loss of one who had its intei-ests so near at heart. Astronomical. — Additional interest has been given to the well-known " Runaway Star," 1830 Groombridge, by the recent spectroscopic detennination of its velocity in the line of sight which has been undertaken by Prof. Campbell at the Lick Observatory. It results from the obsei'vations that the star is approaching the sun with a velocity of 59 miles per second, which is much less than the probable velocity of about 150 miles per second with which the star moves across the line of sight. The obsei'vations are of rspccial importance as demonstrating the possibility of me^asuring the velocities of stars as faint as the 8th or 9th magnitude, provided that their spectra contain well-defined lines. Recent investigations of the spectroscopic binary Mizar (Zcta Ursae Majoris) which have been made at Potsdam indicate that the period is probably 20.6 days, and not 104 days as previously deduced at Harvard. Prof. Vogel further finds that the eccentricity of the orbit is 0.502, and the maximum relative velocities in the line of sight 128 and 156 kilometres per second. The system is approaching with a velocity of 16 kilo- metres per second. A list of 59 " objects having peculiar spectra," given by Prof. Pickering in Harvard Circular No. 60, is of special interest, as 28 of the object* are included in the Large Magellanic Cloud. Of these, 10 are gaseous nebulse, 15 are stars of the Wolf-Rayet type, and 3 ai-e stai's of the first type with some of the hydrogen lines bright; it will thus be seen that the cloud not only resembles the Milky Way in general appearance, but is also rich in types which specially frequent the Milky Way. Among other objects described, five are of great importance as having sjjectra resembling those of the Wolf-Rayet stars, but with tlie lines dark upon a con- tinuous background. Owing to the unavoidable delay in Mr. E. W. Maunders retiu-n to England, the Constellation Study which should have appeared in this number of Knowledge has to be omitted. — A. F. Botanical. — The Revue Horticole for July 16 contains a paragraph respecting the experiments carried on under the auspices of the Imperial Society of Horticulture of St. Petersburg with the view to determine the length of time during which the pollen of various plants will retain its vitality. It is shown that the rose can be fertilised with pollen 22 days old, and species of Clivia when it is 3 months old ; further, a cai>e is cited where the pollen of some hybrid Clivias had not lost all its vitality after being collected a year. In a later number of the Revue, Monsieur Mangin draws attention to his res3arches into the subject published in the Bulhfin , 39(5 pages, U plates, [lortrait. (Paris, 19(X>.) Skptpmbbr. 1901.] KNOWLEDGE. 213 nourishing: situation develops into a female, that one of the others then becomes what he calls " a definitive male," the i-est having either to bide their time for similar chances, or perhaps having to bo content with the lot of Portia's unsuccessful suitors. One genus dis- plavs a kind of inverted Monnonism, a solitary female being privileged to have numeious mates strongly attached to her. Messieurs C'auUery and Mesnil, writing on //'/hci/uVi/.j hnlnui whidi is parasitic on 1 irripi>des, note that this is the only cnixtacean genus vet known in which there are two oviducts on each s:de,§ The ■ Notes on some crustacean paiasites of fishes," by Mr. Thomas Scott, f.l.s.. ought not to be neglected.il Of Dr, Birulas papers on Russian Malacostraca it must suffice to say that though the crustaceans them- selves ai-e not confined to the dominions of the Czar, the discussion of them is, unfortunately for the mono- glot Englishman, exclusively in Russian. I The spirited essays in which the eminent Dar,ish zoologist. Dr. H. J. Hansen, has been appealing to his countn'men to shake off political apathy, to cultivate a stedfast friendship with Great Britain, and to set their scientific household in order, would not come within the scope of this chapter, but for the remarkable appendix on " Rhizorhina, llcrpj-llobius, and Soren Jensen," which the student of Entomostraca ought not to overlook.* Here the account of current carcinology might well have paused, had not the intention of stopping been frustrated by the coincident aiTival of Major Alcock s " Descriptive Catalogue of the Indian deep sea Macrura and Anomala, t and of a pleasant work by the same author, called " Zoological Gleanings from the Royal Indian Marine survey ship ' Investigator,' "| In contrast to the diminutive forms that nestle in corals, the following passage from the " Gleanings '' shows us land-crustaceans liolding their own in the struggle for existence even against vertebrates: — "On Pitti Bank, which is a little uninhabited sand-cay of one of the most submerged of the Laccadive atolls, we found, at the end of November, 1891. vast swarms of a large species of sea-tern breeding. There were nestlings in every stage, but no eggs. Both old and young birds were quite free from fear, the old birds, almost alighting on our shoulders as we landed, and the young birds, even those with their first plumage complete, submitting to capture without any resistance. Dreadful havoc had been wrought among the young birds, chiefly by large Coenobite hermit-crabs, with which the islet swamied, but also to some extent by Ocijpoda ceratophlhalma. The young broods were simply huddled together on the ground, without any soi-t of nest, so that in the absence of the parents they were at the mercy of the crabs. Judging from the bones and sprouting quills that covered the gi-ound, hiindreds of young birds must have perished, and in several cases we saw recently killed bodies lying under a living mound of voracious crabs." § ' Bulletin Seientifiquft de la France et de la Belffique." Tol. 34, I p. 316-362. plate? 17-18. (Paris, 19ss. Thk Hf.mostat IX MicRo.siopY. — The microscopist who has never seen a niicrcscope used in conjunction with a heliostat has yot to learn the possibilities and advantages of such a form of illumination. Residents in the British Isles have a substantial excuse for not usini; the heliostat because of the uncertainty of s^ottinj,' bright sunshine at the time of working ; still the intermittent occasions on which it could be employed would well repay them for their trouble. >[icr08Copists with leisure would find it nioi'C u.scful than those who have few opportunities of workini,' in the day lime, while those who live in foreign countries where continuous sunshine can be depenth at 1.27 P.M., will be new on the 12th at 9.19 p.m., will enter first quarter on the 21st at 1.33 a.m.. and will be full on the 28th at 5.36 a.m. The most notable occultation during the month is that of s Tauri, mag. 37, which takes place on the morninp: of the 5th ; disappear- ance at •i.2 A.M. at 123 from the north point (146^ from the vertex) ; re-appearance at 4.58 a.m. at 22 1 from the north point (230' from the vertex). The Planets. — Mercury is an evening star throughout the month, but unfavourably placed for observation in northern latitudes. Venus is also an evening star, but still unfavourably situated for naked-eye observations. Throughout the month the planet sets about an hour after the sun. On the 15th the apparent diameter is 13"G, and the illuminated part of the disc 0"795. Mars remains an evening star, setting about 8.12 p.m. on the 1st, and about 7 p.m. on the 30th. The ])ath is from the south-eastern part of Virgo into Lil)ra. On the 21st the planet passes about a degree to the south of a Librae. The apparent diameter diminishes from 5"'0 to 4"'6 during the mouth. Jupiter may still be observed in the evening; on the 1st he crosses the meridian at 7.33 p.m. and sets at 11.21 p.m., while on the 30th he crosses the meridian at 5.45 P.M. and sets at 9.33 p.m. During the month the polar diameter diminishes from 39"0 to 35"C. The move- ment of the planet is easterly, through the western part of Sagittarius ; in quadrature on the 28th. The principal satellite phenomena are as follows : — 1st.— I. Ec. R. ... 8'24-2 13th.— If. Tr. I. ... 8 54 2nd.— III. Oe. R. ... 7 46 15th.— I. Oc. D. ... 8 42 III. Ec. D. ... 9 34-9 1 II. Ec. R. ... 8 4.31 3rd.— IT. Sh. I. ... 9 2i I 16th.— I. Sh. I. ... 7 10 6th.— II. Sh. I. ... 8 54 I I. Tr. E. ... 8 10 II. Tr. E. ... 9 12 I. Sh. E. ... 9 28 7th.— I. Tr. I. ... 9 31 ; 20th.-III. Sh. I. ... 7 20 I. Sh. I. ... 10 45 ■ 23rd.— I. Tr. I. ... 7 47 Stlu- I. Oc. D. ... 6 49 I. Sh. I. ... 9 5 I. Ec. E. ... 10 19-2 24th.— I. Ec. R. ... 8 38 9th.— I. Sh. E. ... 7 33 27th.— III. Tr. I. ... 6 5 III. Oc. I). ... 8 27 in. Tr. E. ... 9 13 11th.— IV. Oc. IJ. ... 6 58 29th.— II. Oc. D. ... 8 29 IV. Oc. R. ... 9 28 i Saturn remains a few degrees to the east of Juj)iter, setting on the 1st at 11.55 p.m., and on the 30th at 10.1 P.M. The planet has a slow westerly movement until the ]4th, when it is stationary, and an easterly movement during the remainder of the mouth. On the 15th the major and minor axes of the outer ring are respectively 39"'8 and 17'''2, while the polar diameter of the ball is 15"*8. The northern surface of the ring system is jiresented towards the earth. Uranus is in the soutlicrly ]iart of Ophiuchus, and may therefore be observed i:i the western sky for a short time after stinset. On the 1st the planet .sets about 10 P.M., and on the 3l)th about 8.8 p.m. During the nionth the jilanet describes a short easterly path nearly midway lietweeu Aiitares and i) OphiiK-hi. The planet is in (piadratiire on the (!tli. Neptune is again coming into position for evening ob.servations, the ])lanet rising about 10.30 p.m. at the middli' of the month, and being in quadrature on the 25th. During the mouth a short easterly path is described in the western part of Gemini. On the 14th, the |j]anet is 3 minutes preceding and 15' 20" south of i) Geminorum. The Stars. — About 10 p.m., at the middle of the month, Auriga and Perseus will be in the north-east ; Taurus low down a little north of east ; Aries, Andromeda, and Cassiopeia towards the east ; Pisces a little soutli of east ; Cetus low down and extending from east to soutli- east; Pegasus south-east; Aquarius and Caiiricornus nearly south; Cygnus :\linost overhead; Aijuila and Lyra nearly .south-west ; Hercules in the west ; Corona and Bootes to the north of west ; and Ursa Major nearly due north. Minima of Algol occur on the 1st at 7.36 p.m., and on the 2lst at 9.18 p.m. Cljcss Column. By C. D. LococK, b.a. ♦ Communicationg for this column should be addressed to C. D. LococK, Netherfield, Camberley, and be posted by the 10th of each month. Solutions of Augu.st Problems. No. 1. (W. S. Branch.) 1. Q to 113, and mates next move. No. 2. (W. Clugston.) 1. R to Kt 5, and mates next move. No. 3. (W. H. Gundry.) 1. Q to QB8, and mates next move. [There is unfortunately an alternative method bv 1. Kt to QCch.] Correct Solutions of the three problems have been received from J. Baddelev ('>), H. Le Jeune (0).- G. Groom (7), F. J. Lea, (6), "G. A. Forde, Capt. (7), S. G. Luckock (6), W. de P. Crousaz (7). W. H. S. M. (7), C. C. Massey (G), Eugene Henry (0), G. W. (7), Alpha (6). G. W. Middleton (7), W. Nash (7), A. C. Challenger (7), W. Jay (7), Vivienne H. Macmeikan (6), F. V. Louis (7), C.Johnston (7), F. Dennis (7), J. E. Broadbent (7). A E. Whitehouse has solved Nos. 2 and 3 correctly, W. H. Boyes Nos. 1 and 2. C F. P. scores 4 points for the three problems, 2 being deducted for incorrect claims. /. T. Blnkemore. — No solutions received from you this month. Did you post them ? 216 KNOWLEDGE. [Skptembrr, 1901. F. J. Lea. — Your solutious last month were too late to count. G. A. Forde.—Bx'R will not solve No. ;^. The Black- Queen can give check. But as this is au incorrect claim for a third and not for a second solution, no points have been deducted. W. H. S. M.— F to K.3 is met by Ex P. You never- theless score 3 points for No. 3, for the reason stated immediately above. Correction to solution of No. 2 received ju.st in time. A. F. Wh/lfhonse. — K to B2 exposes the White King to check. C. C. Massey. — Obviously the solution Kt to Q(Jch was not intended by the composer. The solution to tlie June three-mover is, as was clearly stated in the July niunbi'r, P X B, becoming a Bishop, not a " Knight " as you quote. But if Ihe White Pawn were to become a Queen, then the Black Pawn would become a Knight, and stalemate would n^sult. PROBLEMS. By C. D. Luco.-l No. 1. Black (lo). ■_ m II »i*a..^»i msm m ®S Sil Hi w mA ^ mM. m m m m 9 ^ White (i)). White mates in two moves. No. 2. Blach (in. '"- js; Hi 'f§. Whits (S). W^hite mates in three moves. The following are now leading in the Solution Tourney : Furly-five poin/s. — C. Johnstou. A. C. Challenger, W. Jav. Fortij-foiir iioinf.'<.—S. G. Lucko.-k. \V. H. S. M.. G. Groom", F. Dennis, G. W. Middlcton. Forhj-fhree point'i. — J. Baddeley. Forty-tiro points. — H. le Jeune, W. de P. Crousaz, G. W. Forty-one pou>t><. — W^. Nash, J. E. Broadbent. Forty points, — Vivieune H. Macmeikan. Thirty-nine points. — C. C. Massey. Alpha. Tlurty-eiyht points. — G. A. Forde. It will be seen that the number of those who have scored the maximum possible number of points is now reduced to three ; but fifteen others follow them at very close intervals, and the competition is evidently reaching its most exciting stage. The following is the solution of Mr. H. Wnod's prolilem : — Place the White Pawns at Q.">, K5, KB5, KKt5, KR5, KG, KB6, and KKt6. Black's best methods of prolonging the game are — (x) KttoKRS; 1. KtP X BPch, Kt xP; 2. P x Ktch, K X P; 3. P to Ktfich, P X P (best); 4. RP X Pch, K moves ; 5. BP mates. (b) QP X P; 1. P X PBch, K X P (he.st); 2. KtP checks, RP X P (best) ; 3. RP x Pch, K moves; 4. BP checks, K moves ; 5. BP x P mate. G. W. Middleton sends a solution, but with 1) While Pawns. CoRKECTioN. — The composer of the '' eight Pawns ])robleni " has just discovered that Black has a satisfactory defence in 1. KP x BP, and that nine Pawns (the number postulaled by Mr. Middleton) are required for the purpose. As Mr. Wood himself .justly remarks, this necessity for an extra Pawn deprives the puzzle of all its ponit. — *-♦.* — CHESS INTELLIGENCE. A match between Messrs. F. J. Lea and R. Teichmann was recently concluded at 37. King Street, Covent Garden, a former home of the British Chess Club. Mr. Teichmann proved victorious by 5 games to 2. Many chess-]ilayers and others will learn with regret the news of the death of the Rev. J. Coker, of Tingewick, Bucks, at the age of 7ti. Mr. Coker was formerly captain of the Winchester College Cricket Eleven, and played also for Oxford University. As a chess-player he was well known at most of the meetings of the Counties Chess Association, where he was always a formidable competitor. The final contest for the Southern Championship took place at Reading on July 20, when Surrey encountered Ghiucestershire. In order to retain their title Surrey had not only t.j win the match, but to win it by a majority of at least 9^ to 6^, for reasons stated in the August number. With this object in view, Surrey put a very strong team mto the field, and, though the S('oring on the first six boards was quite even, they obtained a decisive majority on the remainder, and won handsomely by 11 gam^s to 5. Mr. D. Y. Mills took charge of board No. I for Gloucester- shire, and defeated the Surrey Champion, Mr. Herbert Jacobs. For Contents of the Two last Nnmbers of "Knowledge," see Advertisement pages. The yearly bound volmnes of Knowledge cloth gilt, 8s. 6d., post free. Bindiii? Cases, I3. 6d. each ; post free, Is. 9d. Subscribers' numbers bound (including case and Index), 2s. 6d. each volume. Indei of Articles and Illustrations for 1891, 1892, 1894, 1895, 1896, 1897, 1898. l>^'yj, and 1900 can be supplied for 3d. each. All remittances should be made payable to the PubUsher of " KNOWLKroE. ' "Kiiovledge" Annnal Subscription, throoghoot the world, 7s. 6d., post free. Communications for the Editors and Books for Eenew should I.p addressed Editors, " KsowLEDOE." 326,-Hiifh Holborn, London, W.C. OCTOHER, 1901.] KNOWLEDGE. 217 MiffiCLilTERATURE A^V Founded by RICHARD A, PROCTOR. Vol. XXIV.] LONDON: OCToUER, 1901. [No. 192. CONTE N TSi • PAOK Flowering Plants, as Illustrated by British Wild- Flowers. — V. Dispersal and Distribution. iiy K. Li.OTn Phakqer, B..\. (Illustrated) ... 217 The White Nile — From Khartoum to Kawa. — IV. Camping and Collecting. J!v Harry F. Witiierby, F.Z.S.. M.li.o.r. (IllustrateilJ ... 220 Plant-bearing Hair. Hy R. Ltdekkeb 22;i The Total Solar Eclipse of May 18, 1901. By E. Walter MArXDEB, F.R.A.s. (Illustrated) ... ... ... 225 The Corona of 1901, May 18. (Piute.) Constellation Studies. — IX. The Sea-Monster and the Flood. By E. A\'alter Maukdeb, f.r.a.s. fllluslrafeitj .. . Obituary :— Prop. Baron von Nordbnskjold Letters : Thk DlSTRIBrTIOX OP THE SlAES IX SPACR By .ARTHUR Ed. Mitchell. Note by the Eds SlTDDBN Blancuixo OP HuMAJf Haib. By Sir W. R. GOWBRS. Sr.D., F.R.S. A Triplb Raisbow. By G. McKenzie Knight MOTUING IX SrPFOLK. By Jo3. F. Green SuNSPOTS AND LiGHT. By A. Elvins. Note by E. W. Mauhdee ... Notices of Books Books Received British Ornithological Notes. WiTHBBBT, F.Z.S., M.B.o.r. ... Notes The Mechanism of a Sunset. Microscopy. Conducted by JI. I. Notes on Comets and Meteors. F.B.A.S The Face of the Sky for October. By A. Fowleb, F.B.A.S. ... Chess Column. Conducted by Habbt F. By Aethue H. Beli. Cboss. (Illustrated) By W. F. Denning, Sky By C. D. LococE, b.a. 228 230 231 231 231 2:!l 232 232 233 233 234 235 237 238 230 240 FLOWERING PLANTS, AS ILLUSTRATED BY BRITISH WILD-FLOWERS. By R. Lloyd Praeger, b.a. v.— DISPERSAL AND DISTRIBUTION. To resume the consideration of the means employed by plants to ensure a wide dispersal of their seeds. We have seen how much the available motive agents — wind, water, animals — are taken axlvantage of. There is, in addition, a large number of plants which do not rely on any external agency to cany their seed, but do the scattering themselves, by one or another ingenious device. If we lie on a sunny bank among the Gorso in August, we shall hear a sharp snapping noise coming from the prickly bushes at frequent intervals. This is due to the sudden rupturing of the ripe pods, owing to unequal- shrinkage caused by their drying. The walls of the fruit are composed of layers of colls which vary in the amount to which drying causes them to contract. When the stress due to the irregular contraction thus produced reaches a certain point, the walls give way. and each half of tho pod jerks into a spiral form, projecting the endoscil seeds to a considerable distance. Examine a fruit of tho common Dog Violet. It is a little capsule formed of three sections. As it ripens it opens along the lines of junction of these, and wo get three narrow boat^shapcd valves spreading horizon- tally from tho fruit-stom, and each containing sevoral seeds. The drying of these valves causes contraction. Tho two gunwales, so to speak, of each boat are drawn together, "pressing more and more tightly on tho seeds which lie between, till one by one the seeds spring out with considerable force. In other cases a similar violent expulsion of the seeds is caused by unequal growth in the tissues of the seed- vessel. This it is that produces such a stato of stress in tho five-parted capsules of the Touch-me-not that when ripe a puff of wind or a light touch causes a violent explosion of the fruit, by which the seeds arc scattered far and wide. A moro familiar example may be studied in the little Haiiy Cress, so common a weed in gardens. While weeding a lx;d early last June, in which there was a quantity of this plant, which had unwisely been allowed to excewl tho period of flowering, the bursting of the little narrow pods and the flinging of hundreds of seeds in my face amounted to a positive nuisance, and caused reflections concerning the wisdom of an old saying about a stitch in time. Some of tho Crane'srbills fling their seeds to a con- siderable distance by means of a moro complicated apparatus. The fruit consists of five separate caijicls attached by their apices to a spindle. Each carpel con- sist^s of an egg-shaped pouch containing one seed, pro^ Fio. 1.— Tlie I'.Ioody Craut-'j-bill, sliowiiig slins-fruit. I nat. size, longed into a slender rod, the whole adprcsscd to the spindle, so that the five pouches lie in a ring round its base. Each pouch is open on the side which is pressed against the spindle. As the fruit ripens, the more rapid shrinking of the outer layers of the rod of the carjiel causes it to rupture the tissue which attaches it by its whole length to the spindle, and it curls with a jerk, cariying up the pouch, and causing the seed to fly out 218 KNOWLEDGE. [OCTOBEB, 1901. Fio. 2.— A Fruit of the Musty Stork's-bill. X 2. of the opening on its inner side already referred to. Lord Avebui-y placed fruits of the Herb Robert, on his biUiai-d-table. and found that the seeds were in this manner projected to a distance of over twenty feet. Fruits of this kind have been aptly named sling-finiits. Nor is it beyond the powere of certain species to under- take even the phmtinri of their seeds. The Stork's-bills (Erodium). which ai-e closely allied to the Crane's-bills or Geraniums, have curious fruits, each consisting of a torpedo-shaped seed prolonged into a slender twisted rod. which terminates in a long appendage set at right angles to the axis of the remainder of the fruit. ■ The seed is furnished with bristles pointing away from the unattached end; and the twisted tail is hygi-oscopic — very sensitive to moisture. Xow, if the seed be held fast, and the whole moistened, the rod will untwist, and as a result the free end will revolve like the hand of a flock. But if, as will more likely happen in nature, this revolution causes the long appendage to come in contact with some obstacle — a blade of grass, for instance — then the motion will be transferred to the seed-bearing end, which will revolve like an auger, and, as a result of the lengthening caused by the untwist- ing of the rod, the seed will be forced intothe ground. Theupward pointing bristles will come into play if the rod dries again, tending to hold the seed down in its place in spit« of the contraction, and to drag down the opposite end instead ; another moistening will cause the seed to buiTow deeper. A much simpler, but vei-y pretty instance may be watched in the little Ivy-leaved Toad-flax, a plant of the European continent which has now spread over the greater part of the British Islands. It grows on walls, and when in flower the prettv piu-ple Snapdragon-like flowers stretch out towards the light and air. But as the finiit ripens its stem bends towards the wall, and seeks the deepest cranny it can find, in which the seed may be deposited. ' Owing to this arrangement, the fruit needs no winged appendage or other device such as is possessed by so many wall plants, to prevent the seed from falling uselessly to the in- hospitable gi-ound below. Thus far regarding the dispersal of plants by means of their seeds. We have not yet nearly reached the hmit of power of spreading which our ■ wild flowers possess, for vegetative reproduction plavs a most im- portant part in this chapter of their life-historj-. We may, if we wish, separate the latter processes into two gi-oups, according as to whether the new shoot separates from the parent plant, or remains, for some time at least, attached to it. In aU cases it is of great im- portance to note that reproduction of this kind is not due to the nff.-- of the species are perennials, almost the only annvials being the group last mentioned, which are certainly advantageously circumstanced. The plants comprising such an association must be very hardy species, able to iiold their own in a keen struggle for room, and to produce fresh leaves and perfect their flowers and fniit in spite of the depredations of the sheep and cattle. Or t/O take, finally, the vegetation in the centre of a great turf-bog. Here, again, we revert to conditions entirely uninfluenced by man or by grazing animals. We have again a strongly dominant species — the Ling. Competing with it for dominion we may have one of several others — the Bog Asphodel, or one of the sedges. The supremacy vai'ies according to the degi-ee of mois- ture. On the drier portions, the Ling easily holds its own ; but where the peat is wetter, the Bell-Heather is a dangerous rival ; and where water usually lies, the Beak-rush holds sway. Compared with the flora of the pasture, the variety of plant-life is very limited — per- haps not more than] a dozen species in as many square yards; very few plants can tolerate the peculiar con- ditions which prevail — the intensely peaty soil, the soak- ing spongy ground, and the competition of the over- mastering Ling. THE WHITE NILE FROM KHARTOUM TO KAWA. AN ORNITHOLOGIST'S EXPERIENCES IN THE SOUDAN. By Harry F. Wituerby, f.z.s., m.b.o.u. - IV.-- CAMPING AND COLLECTING. Whilst travelling up the river we had noted different places where the country seemed most suitable for bifds, and for making collections. Arriving at such a spot on oiu' rctuiMi journey, if satisfied with our fonner clioice, we selected the shadiest tree available under which to pitch October, 1901.] KNOWLEDGE. 221 tho tents, aiid setting our " trusty " followers to work, wo soon had a camp neatly .irratigod and in workini; order. While one of us remained in camp, the otlior two sallied forth to the hunt. Most of our work was done between live aiul eleven in the morning. From eleven to three we rested in the sluvde, and from three until sunset wc were collecting again. But the morning hours were generally the most profitable, the afternoon being hotter and often spoilt by a Siuidstorm, while in the evening a necessarj' slaughter of pigeons for the pot usually had to bo undertaken. When out collecting each of us was accom- panied by a man to cany the birds, and perhaps a spare gun and a wat«r bottle. Wlieu five or six birds had been shot the man was sent back to camp with them so that no time should be lost in tlie skinning, and as decomposition often set in within two or three houre after death, wo found this plan necessaiy as well as convenient. For caiTving the birds we employed a stick, to which were tied at intervals pieces of thread. a space being left in the middle of the stick for the hand. To one end of each piece of thread was tied a small bit of cork and to the other a pin. When .i bird was shot the pin was pushed through its nostrils and into the cork. The bird thus hung free from the stick and its plumage was in no danger of being rubbed and injured. Only one of our men showed any liking to come out shooting. They were not sportsmen. In- numerable excuses wei'c invented when they were told to accompany us. But excuses were vain — answers could also bo invented. Was illness pleaded — pills were administered, a species called the " Livingstone rouser " being most effective, but the man must come. Did a man say that he had lost his shoes and covild not walk through the thorns, then he must take another's shoes and be quick. We had no mercy, nor had the com- panions of the malingerer. They laughed like children when an excuse was silenced. As is always the case, or at all events wherever I have collected, certain birds, and generally tho common ones, interfere with the collecting of others. Wc were much annoyed by a species of babbler* of about the size of a blackbird, and of a light brown colour, but with a white head, which w-as lucky for us, as it made them conspicuous and so easier to avoid. They were common where the trees and bushes grew thick, and were always in small companies. When wc were unfortunate enough to come suddenly upon one of these companies the babblers seemed to go mad — whether with rage or teiTor I never could determine, and assailed us with an in- cessant stream of the hoarsest alarm-notes. This noise, for it can be called nothing else, was made up of a number of " churrs ' so rapidly repeated that the whole sounded like a policeman's rattle turned with feverish anxiety. Moreover, the birds pcrforiued in company, sitting side by side on a bough and often touching one another. Were you so unwise as to try and drive them away they only retired to another bush and redoubled the noise. If you tried to creep away they followed you advertising your presence to every other bird, and it was a long time before you could finally shake them off. Then there were four kinds of pigeons that were numerous and would rush out of a tree which you were carefully approaching, with such a fiap that all the other birds took alann, and a thick tree often contained twenty birds or more. In another way we were handicapped by * Craleropun hucocephalus (Crctzsclim). two little birds, the pallid warblorf a«d the ksscr \vhitethroat.| The luajorilv of the l)irds in evci'y thick tree or bush were sure to bo cither pallid warblers or whitethroats. Tho difficulty was to discover what else the bush contained. Ma.ny of the bushes were so thick that it was not until the birds came near the edges that they could be seen. A thorough examination might occupy a quarter of an hour and then poihaps no other birds but these two would be found. A good pair of binoculars is in every way the ornithologist's best friend, and although a glass should not be relied upon to too great an extent in identifying birds, it was of the utmost service in this work. I was the happy possessor of a pair of Goerz's Trieder binoculars. Eveiyone praises his own glass, but of all those I have tried iiono has been so good as this glass for my purpose. The power which magnifies nine diameters can Ijo focussed and used perfectly easily with one hand, which is a great advantiigo, tho definition is excellent, and although the '■ field '' is not large, the glass is so light that it can be moved about quickly and with a little practice even a flying bird can bo " piclted up " immediately. In this country of dense bushes and tame birds a knowledge of the notes of the birds was most valuable and a great saving in time. By a systematic identifi- cation of the performers all the commoner notes were quickly learnt, and then an unknown or doubtful sound proceeding from a thick bush at once drew attention. By moans of these notes many of the rarer and smaller bii'ds we obtained were first detected. For instance, one day I had got to the fringe of the wooded tract of countiy and had reached the beginning of the desert when I hoard the sweetest possible little note proceeding from a thoni bush. Tho bush, although quite leafless, was so thick with green shoots that I could see no bird in it, but the note was so soft and delicate that I knew| it must have been uttered by a tiny bird. I went some paces away and waited. After a time four or five most elegant little bush warblcis§ appeared on the outsido of the bush. Most refined little birds they were with most channing actions. They moved cjuickly and giacc- fully from twig to twig, and often fluttered to' the ground in their search for insects, and except when actually flying they were incessantly flirting their long tails from side to side with a quick, jerky but dainty motion. Wo aft^jrwards found these little birds in the acacia trees bordering the desert, and heard their wiu-bling song, which was so soft that a near hearing and perfect silence were necessary for it to bo fully appreciated. In some ciises, however, neither our glasses nor oiu- oars were of any sei'vice in determining the species of a bird. Two birds which we obtained I thought at the time were reed warblers,|l but on a comparison at homo one of them proved to bo a marsh warbler.^f Both these sjjecies come to England in the summer, and here in their breeding haunts their difi'crcnt nests and songs and habits make them perfectly distinct. But the birds we ob- tained were migrating from their winter abodes, perhaps much further south. Tho habits ai)peared to be exactly similar, they were not in song, nor did we hear them utter even a call note, so that there was nothing to differentiate them except their size or plumage. But in size they are exactly the same, while even, with the two bii'ds side by side in the hand their plumage is so t Hypolais pallida (Hcniin-. et Ehr.). J Sylvia curruea {\ Ann.). § SpilopHla c?a«ia»« (Teniiri.). {| Acrorrp/ialus -ilrepeni.i (Viiill.). •[ Acroccphalus palustris (Boclut. ). 122 KNOWLEDGE. [October, 1901. similar that no one but an expert would detect the difference. It was most interesting to come across birds with which one was familiar in England in their winter resorts or on their migrations so far to the south. The extraordinary power of the migrating impulse was Fio. 1. — Camp at Duem. brought vividly home to mo by the presence of a solitary red-throated pipif-^* feeding on the banks of the river some 1400 miles south of Cairo. Less than a yeai- before I had seen this bird in its breeding haunts beyond the arctic circle in Russian Lapland, and I knew that it only nested north of the tree^■limit. When I recalled my own journeys by boat and rail round the North Cape and then again down to Khartoum, and looked at the lonely, delicate little bird before me. it was almost impossible to realise that tho.se feeble wings would in a few weeks' time be transporting that tender little body beyond the arctic circle. I have said that we rested in the heat of the day, but a variety of causes generally kept us busy. There were birds to skin and label and pack, and notes to be written, then a gun was always kept handy, even at meal times, for the unknown birds which would often come unwarily into the tree over our tents and proclaim themselves by their notes. There were sheikhs to be salaamed and interviewed, and then our own followers required much attention. They stole from the natives, who natui-ally complained, they neglected the animals and the few duties we were able to put upon them, they were continually drunk with " boozer," and were always quan-elling and threatening one another's lives. All these little affairs had to bo enquired into and dealt with during the mid-day "rest." Correction had to be ad- ministered usually in the form of the " korbag," laid on with no sparing hand by a companion of the delin- quent. But they were accustomed to this, and a more effective form of punishment, resei-ved for special occasions, was to administer a kick with precision and l^ower as though one were " placing " a goal at Rugby football. This not only hurt and surprised, but had the additional advantages of wounding the dignity of the kicked, and of bearing gratifying results to the kicker. Catering for ourselves and our followers also had to be attended to, and this sort of conversation would often ensue: — "Hassan, why have we no eggs in this camp when there is a village quite close? " " Ah, effendi, dey *• Anihus cervinus (Pall.). no buy (sell) eggs in dis village, all dee people want to make dee chickens." To sleep during the mid-day rest was somewhat difficult. The temperature in the shade rangetl from 100° to 115° Fahrenheit during the hot hours. There were also innumerable insects of various sorts in every camp. Ants of several kinds ran over us and bit us in the day time as well as at night. There were mosquitoes, find flies and small biting beetles in most places, while huge hairy spiders and enormous hairless ones of foi'ocious attitude and powerful jaws often ran about inside our tents, but luckily these never preyed upon us. In one camp we were assailed by a. whole army of little bees, which were extremely diligent in building small cocoon-shaped nests of mud in om- bedding, boxes and clothes. At night the nests were tenanted by their builders, which resented a disturbance of their hardly- earned rest, and used their stings so freely that w-e were obliged to search carefully for the nests and burn out the defenders. Large black hornets were numerous, but inoffensive if not molested. We yeanied to catch "and train one of the brilliant plumaged bee-eaters, of which there were four kinds in the country, to attend upon us and protect us from these noxious insects. A bee-eater fears no insect.. I saw one of a small varietyft sitting on a twig suddenly dart into the air and catch a great hornet in the tip of its long bill. Retumiug to its perch with this delicate morsel, the beefeater crushed it thoroughly by passing it to and fro through its beak and then suddenly swallowed it whole. In our camps furthest to the south white ants were a scoiu-ge and their ravages had to be carefully guarded against. All the baggage had to be moved and examined two or three times a day, and so quickly do these pests get to work that during a single night any article left lying on the ground will be com- pletely covered with the sandy secretion, under which the ants operate, and will be" half destroyed. Where these ants were numerous the trees were entirely brown with their workings, and the fallen trunks and boughs were not only brown with the protective covering but Fig. 2.— Camp at Gerazi. eaten through, so that at every stej) on an aj)parent mound of earth one crushed through the shell of a fallen ti"ce. The most amusing visitors to our camp were the monkeys, which were numerous between Duem and Kawa. They were very tame and used to come regularly into the tree over the tents, and after a tremendous romp, would nestle up to each other and sleep for hours. +t Meroj>s pusilhs, P. L. S. Mull. October, 1901.] KNOWLEDGE They were grivct monkoys.|i of a beautiful greeuish-groy on I lie back, with whitisli bi"cast#, and bhiok faces adorned with handsome white whiskers. We uotiied tliat "they were very fond of tJie gum which exuded from the acacia trees. But mammals of any kind were scarce iu the couutiy wo worked, and we did not travel far enough south for big game. Occasionally a gazelle or an ;uitelopo woidd be seen, but they were rai'o and shy. Ill two or tlu'ee places there were hares, and it was while I was chasing a wounded hare through some rough grjiss that I came across the only bird new to science which we discovered. This was a tiny fantail warbler.§§ of a most delicate light sandy coloiU' on all the upper paj-ts and with a silveiy breast — a colouring most suitable for the brown grass and sandy countn- which it inhabit<.»d. I only obtained one speci- men, and It is somewhat risky to found a new species on a single example, but the Hon. Charles Rothschild has lately obtained an exactly similar bird near Shendy. so that the claims of my new species may now be con- sidered as established. The photogi-aphs, with which this seiies of ai-ticles is illusti'ated, were taken by Mr. C. F. Camburu, to whom I am much indebted for permission, to make use of them. PLANT-BEARING HAIR. By R. Lydekker. Although the name " sloth ' is not unfrequently mis- applied by travellers to the slow lemurs of India and the Malay countries, or to their cousins the galagos of Africa, it should, as many of my readci-s are doubtless aware, be restricted to certain peculiar mammals inhabiting the tropical forests of Central and South America. In addition to the simple (Character of their teeth, which are confined to the sides of the jaws, sloths are chai-acterised by their short faces, rudimentary tails, shaggy coats, and hook-like claws by means of which they hang suspended, back-downwai'ds. from the branches of the trees among which their lives are spent. Two very distinct tyjjes of these animals are known, readily distinguished by the number of toes on the fore- limb. In the one form — the three-toed sloth — there are three claws on each foot, both in the front and the hind limbs. But iu the other — the two-toed sloth — there are only two claws on each of the fore-feet. These, however, are by no means the only differences between the two types (and I say types rather than species, because ifc is quit© probable that each modification has more than a single specific represen- tative). In the first place, there is a difference in the form and position of the first tooth in each jaw. In the three-toed sloth, or ai, for instance, this tooth is similar in form to those behind it, from the first of which it is separated by a space not longer than the one between the second and third. In the two-toed form, on the other hand, the fii-st tooth is taller than those behind, and has a bevelled, instead of a flat gi-inding surface, while the space dividing it from the second much exceeds that between any of the others. Again, the front of the upper jaw of the two-toed sloth carries a T-shaped bone, corresponding to the pre- maxillae of other mammals, which is totally wanting in the other form. The front of the lower jaw of the former is also prolonged so as to form a kind of spout, of which there is no trace in the latter. In both these respects the two-toed sloth comes much nearer to XX Cercopithecu3 aabaeiu (Jjian.). §§ CiXicofo aWt^aZo, Witherby. the extinct ground-sloths (oi which we have lately heard so mucii) than is the ca.sc with its three-clawed cousin. Again, if the males of the three-toed sloth be examined, there will be seen a patch in the middle of the back where, owing to the absence of the long coarse extresent article. 224 KNOWLEDGE. [October, 1901. either salt or fresh — comparatively few deriving their nourishment from the moisture contained in tlie air. Some, indeed, are confined to particular descriptions of rock, and possess structui-es recalling roots, but even in these cases it is doubtful if they draw more than an insignificant fraction of their nutriment from the substance on which they grpw. In the moist tropical forests forming the home of the sloths the algae in the cracks of their hairs glow readily, and thus communicate to the entire coat that general green tint, which, as already said, is reported to render them almost ' indistinguishable from the clusters of lichen among which they hang suspended. " In thick transverse sections of the hair," writes Dr. Ridewood, " these algal bodies show up very clearly, since they stain deeply, and have a sharply defined circular or slightly oval outline. Unless the hair is much broken, they are confined to the outer parts of the extra^cortical layer." Not the least curious phase of a marvellous subject is that the two-t«ed slotb, although the structure of its hair is very different from that of the ai, also has an alga, which belongs to a species Cjuite distinct from the one found in the former. In the two-toed sloth the hairs lack the outer sheath investing those of the ai, and consist chiefly of the central core of coi-tex; in other words, they conespond to those hairs of the latter from which the outer sheath lias been shed. The surface of these hairs is dis- tinctly furrowed with longitudinal grooves or channels, and it is in these channels that the alga distinctive of this particidar species is lodged and flourishes. After stating that a solution capable of exhibiting the absorption bauds of the vegetable colouring matter chlorophyll can be obtained from the hairs of this animal. Dr. Ridewood gives the following particulars with regard to their structure : — " The hairs are, as a rule, coaise, and with a single curve extending over the greater part of the length, while the basal fourth or so is wavy; but in young specimens, and in some apparently adult examples from Costa Rica, the hair is vei-y delicate and soft, and siNuous from base to point. However, in these forms the hairs .... have only two or three furrows instead of the more usual nine, ten, or eleven. The algre, also, arc quite absent from many of the gi-ooves. When such an empty groove is examined in optical section ■ it exhibits the outlines of obsolete extras cortical cells In baby specimens more than half of the hairs ar-e slender non-medullate cylinders, with a very distinct scaly cuticle, and no grooves on the surface." These simple hairs are, in fact, the only rudiments of an under-fur possessed by the two-toed sloth, or unau. • It may be added that in the presumably extinct ground-sloths (the skin of one of which has fortunately been presei-ved to us in a cave in Patagonia) the hairs are solid, without (according to Dr. Ridewood) any trace of the outer sheath of those of the ai, or of the flutings characterising those of the unau. These ai-e thus evidently of a less specialised type than is the haii7 covering of the modern tree sloths, as indeed would naturally be expected to be the case in the members of the ancestral group to whicii the latter ]n-obably trace their descent. The above, then, aiv the essential facts with reirard to the peculiarities of their hair by means of which the sloths are brought into such special and remarkable hamiony with their environment, and it now remains to consider how best to explain their origin. Of all the problems with which the naturalist has to deal those connected with the " mimicry " of one animal by another, or the special resemblances by cei-tain animals to their inanimate surroundings, are some of the most difficult, and the present instance forms no exception to this rule, if it is believed that ' natural selection," or some such mode of evolution, has been the sole factor in the case. In this instance, at any rate, there can be no question as to any volition on the part of the animal concerned having aided in the development of its protective resemblance. And, on the hypothesis of natural selection, it appears necessary to assume that when the modern types of sloth were first evolved no alga grew in the hair of these animals, which were consequently able to exist and flourish without any such adventitious aid. The nature of their hair formed, however, in the case of each of the two groups, a convenient nidus for the lodgment and growth of an alga; and such a suitable situation was accordingly in each instance seized on as a habitat by one of those lowly plants. At first, of course, only a certain number of sloths would have had alga^produciug hair, and these, from the green tinge of their coats, would consequently enjoy a better chance of escape from foes than would their brethren which had not yet acquired the greenish garb. And, on the assumption that alga-growing hair is inherited, their progeny would consequently have the best chance of winning in life's race. It is, of coiu^se, not difficult to assume that when the alga had once become firmly established as pai't and parcel of the hair of each group it acquired in both cases distinct specific characters, even if there were not originally two kinds of these plants concerned. And here ai-ises one of the many difficulties connected with this sort of explanation. It is quite clear that an alga would have been of no advantage to the sloths until they had acquired their present completely ai-boreal kind of life, and sisce there is a considerable probability that both types of these animals were independently derived from some of the smaller ground- sloths, it follows that on two sepai-ate occasions an alga has independently taken advantage of this suitable vacant situation and adapted itself to its new surround- ings. This difficulty, like the one connected with sloths having flourished before they accjuired a lichen-gi'owth, may appear of little importance to those who are con- vinced of the all-sufficiency of natural selection, but to others it may (if well founded) seem more serious. As we have already seen, the structure of the hair in the two types of sloth is, each in its own way, absolutely peculiai', and has therefore doubtless some special purpose. And, to put it shortly, the question consequently is whether these two tyj^es of hair structure were specially developed for the reception and growth of algre designed to aid in the protection of the animals on which they occur, or whether such develop- ment has taken place for some totally different object, and that the subsequent growth of the algie, and the additional protection thereby afforded, have been purely fortuitous. The fact that the hairs themselves assimilate the body of the sloth to a lichen-clad knot, shows that their peculiai- character is largely protective, and it would be a most cvn-ious coincidence had this protective OCTOBBR. 1901.] KNOWLEDGE. 22.5 resemblance been enhanced by an aocidcnt-al growth of algje. As regards the manner in whitli tho growth of algne is maint-aiuetl in the sloths from one generation to another, the only rational explanation which presents itself is that, the young sloths become infected with alga-spores from their parents. As already mentioned. Dr. Ridewood has pointed out that in very voung individuals of the two-toed sloth a large proportion of the hairs are devoid of grooves; and it would therefore seem that the young sloths do not develop a growth of alga till about the time they are old enough to leave the maternal arms and hang independently on the leafy .ind lichen-clad boughs of their native foixsts. THE TOTAL SOLAR ECLIPSE OF MAY 18, 1901. By E. W.\I.TER Jf.WS'DER, F.R.A.S. The striking success which attended the observations of the eclipses of 1898 and 1900 has gone far to make people forget that conditions so favourable are very rai-ely obt^iined. On both occasions we had the shadow track passing for an immense distance through settled and civilized countries easily reached from abroad, and where all necessaries and conveniences could be readily procured. On both occasions, too, a great number of expeditions were organized, and many obscr\'ing stations occupied, and evei-yone, without exception, enjoyed fine weather. This must be regarded as most phenomenal good fortune, which it was again.st every probability would be soon repeated. There is therefore no need to feel disappointed that the same unusual degree of success did not attend tho eclipse of last May. It was one of specially long duration, but its geographical con- ditions were of the tantalizing character which are almost inseparable from such. The shadow track lay near the equatoi-, and this being so, it was inevitable that much of it should lie across the open ocean or countries neither accessible nor civilized. Broadly speaking, only two limited regions were sufficiently accessible to tempt astronomers. For the eclipse at morning, the islands of Bourbon and Mauritius were available; whilst the west coast of Sumatra had it in the early afternoon. A French expedition, under M. Deslandres, went to Bourbon; whilst Mrs. Maunder and myself went to Mauritius. But the chief stream of observers flowed to Sumatra, attracted, no doubt, by the unusual length of totality there ; and some eight or ten distinct expeditions, English, American, Dutch and Japanese took up their stations at Padang or within a few miles of it. This limitation of observation to two very restricted areas stands in great contrast to the experiences of 1898 and 1900; but it cannot be doubted that it was imposed upon astronomers by the conditions of the case, and a similar limitation has been found imperative in the majority of eclipses. As I have not yet had the opportunity, since my very recent return to England, of leaining much as to the details of the results obtained by the numerous parties in Sumatra, I must restrict my present account entirely to the Mauritius observations. From its situation, far out in the Indian Ocean, and nearly under the Tropic of Capricorn, Mauritius is in an extremely favourable position for the study of the great movements of the atmosphere. To the north of the island lies the equatorial belt of calms, with its hot. damp and rarefied atmosphere; to the south, tropical calms characterized by their cool dry atmosphere and high bai'ometric pressure. These two belts do not re- main in a h.^ced position but move northward or sovith- ward with the sun. Mauritius therefore comes at one time of the year into tho one belt, and si.K months later into the other, whilst for the greater part of tho year the island lies in the track of tlie south-east trade winds. During the period that the sun is vertical, or nearly so, over the island, there is a liability to fierce cyclonic disturbance, the actual centre of which may or may not pass over the island, but the passage of which may make itself sensible even at the distance of luuidrcds of miles. Further, beside tho observations which can be made on tho island itself, it stands in the great highway fiom tho Cape of Good Hope to India, a highway which was for long the chief route from England to India. It therefore was, and still is to some extent, a place of call for a largo proportion of the vessels navigating the Indian Ocean, and the logs of the ships putting in heie afford the means for ascertaining tho general state of tho weather over the entire ocean. This favourable position drew the attention of a traveller, Mr. C. Meldrum, who half a century ago had the misfortune to be wrecked on Mauritius cm a voyage from India to the Cape. Frmn this Hiiic lie made the jrjtj I, — Koval Alfred Observatory, irauritiiis. Tin- group of trees on the left-haiid siilo of the picture hiul to be cut ilowu to a lieiglit of 10 feet iu order to give a lAoar view of the l')elip9e. island his home, and the study of the atmospheric dis- turbances of the Indian Ocean his life work. He founded the Meteorological Society of Mauritius in 1853, and was for many years its secretary; he collected and copied the logs of as many of the vessels as called at Mam-itius as he could obtain; he procured tho establishment, first of a modest meteorological obser- vatory in Port Louis, the capital, and later, as the value of his researches became better known and more appreciated, of a larger and more comi)lotely fitted one at Pamplemousses, some seven miles to the north. The foundation stone of this new institution was laid by H.R.H. Prince Alfred, Duke of Edinburgh, during his visit to the island in 1871, and it still bears his name. The selection of Pamplemousses as the site of the new observatory has proved a most unfortunate one. This could not have been foreseen at the time when the erection of the observatory was resolved upon. Mauritius was then, except for a few sporadic cases, quite free from malarial fever, and the broad level plain 226 KNOWLEDGE. [October, 1901. not only offered a good horizon in almost every direction, but was the chief residential district of the island, and as it still is, the most fertile. But in 1867 there was a virulent outbreak of malaria, and before the Observatory was completed, it had become endemic in Pample- mousses, and the European population had been driven away and forced to seek refuge in the higher country on the further side of the capital, and the gateways of old country houses and widesprcading yet crowded cemeteries alone remain to testifv to the former popu- larity of the district. The chief purpose of the observatory was. of course, meteorological; the study of the laws of storms, and the prediction of cyclones, the chief items in its programme. But astronomy was not neglected, and it was furnished with three instraments of respectable size and quality. These were a transit instrument of 3-inches aperture, an equatorial of 6-inches, and a photoheliogi-aph of 4-inchos. The existence of an obsei-vatory of this size and situated close to the very centre of the shadow track was a circumstance that could not be overlooked in the choice of stations from whence to observe the eclipse. There was a yet further reason why the Astronomer Royal should have selected the Royal Alfred Observatory, Mauritius, as one of the stations to be occupied by one of the eclipse expeditions which he was sending out. The Du-ector, Mr. T. F. Claxton, f.r.a.s., and his chief assistant, Mr. A. Walter, were both former membei-s of the staff of the Royal Observatoi-y, Greenwich, and an intimate connection has been kept up between the two obsei"vatories for the last seventeen years, in that the photogi-aphs of the sun taken at Mauritius, so far as they are required for the completion of the Greenwich series, are regularly sent to the latter obsei-vatoiy for measurement and reduction. In coming to Mauritius, therefore, we came to friends and colleagues, who welcomed us as such, and who Fio. 2. — Mr. Cluxton's Stiiiion iit the Ei-lipsc. showing tlio !M:inritins Photoliolio|Trapli and the Rapid Ri'ctilinear Caimn-a imiuntcd horizontally in t-onneetion with the 16-incli C'a>lo.stat. spared no trouble or pains to secure the success of our work. Wo reached the island on Saturday, April 20, and on the following Wednesday took up our residence at the Observatory, not without many warnings fiom Government officials medical men and friends that we were doing a very risky thing. It was a I'isk, however, that we were obliged to face. We were bound to use to the uttermost the advantages offered by the instru- ments and buildings of the Observatory, so that we were precluded from seeking an eclipse station elsewhei-e in the island ; and we could not make the Observatory our station unless it was to be also for the most part our home. For from the Observatory to the healthy country on the central plain of the island is a journey of more than two hours' length by rgad and rail, and the trains only run during the hours of daylight. If we had lived away from the Observatory, therefore, our working hours would have been very short, and it would have been impossible to make use of the stars for focussing and other adjustments of our instruments. We were not at all inclined to regret this necessitv 1 il .;. '.li- Mauuiler's, Station at the Eelipsp, showino; the Grreenwich Coronagraph and the Evershed Prismatic Camera mounted in connection with the 12-inch Ocelostat. at first. The Observatory is a handsome building, standing in eleven acres of its own ground, and its sur- roundings are very pleasant to the eye. The climate was hot, damp and somewhat enervating, but being tempered by the breeze which sprang up every day soon after noon, was far from being unpleasant. A more serious drawback lay in the difficulty of getting sufficient manual assistance, though this was partly overcome by the kindness of the military authorities, who allowed live non-commissioned officers from the gan-ison who liad volunteered for this work to come down for one day to unpack our instruments, and nine to assist us in the observations on the day of the eclipse. A yet further, and most important help was that one of these — Staff-Sergt. Ralph Smith, a.o.c. — was allowed to place his services at our disposal pretty nearly continuously for the three weeks preceding the eclipse, and to his skilful hands we confided the care and treatment of the driving clocks of our telescopes and ccelostats. The programme which Mr. Claxton and myself pro- posed to can-y out in combination, comprised the photo- graphing the corona with three instruments, all of the same aperture, but of vei-y different construction and size of image, so as to secure delineations as perfectly as possible of its three chief regions. The photo- heliograph of the Mauritius Observatory was the first of these, and gave an image of the sun nearly eight inches in diameter. With this instrument only the prominences and the very lowest region of the corona could bo obtained. Next came the Greenwich corona- graph, giving an image 2j-inchcs in diameter. With Knoirlediie. NORTH UJ CO < LlJ SOUTH. Exixiiure, 2 seconde ; Time, 22 scromls alter Second Coiitiicl ; I'latu, Imperial '' Fine Gniin." NORTH. W UJ 5 CO < SOUTH. Exposure, b seconds; Time, 145 second.* alter Second Conliict ; Plate, Im|>crial ' Kiiic Grain." THE CORONA OF 1901, MAY 18. Photographed at the Royal Alfred Observatory, Mauritius, with the Newbegin Telescope ; 4, inch Cooke Photo visual Object Glass ; Focal Length, 71 inches. OcTor.EK, 1901.] KNOWLEDGE this the corona in general was sought to bo securc