1 EARSWELL CO.I-imluX Bookblndm, y JlTJniSi. i TORONTO . \ THE PROPERTY OF OF CANAtiA, TORONTO, ONT. "u»-tRTY OF Y<^ feal |stranom>r:r; |pdrlp OFCANAO^, TORONTO, 0^4T. louiiaca U> Uicl.:ud A. I'roirlor, i3ii. With which is incorporated Hiirdwicke's Science Gossip, and the Illustrated Scientitic News. A Monthlv Record of Science. i-nNniTTKn nv Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A. Let Knowledge grow from more to more." — Tennyson. Volume XXXV. New Series, Volume IX. 1912. London : Knowledge Publishing Company, Limited, 42. Bloomsbur)- Square, W.C. INDEX To Volume WW N e\v Se \'olui IX. (1912). ADJUSTMENT. THE FINE. 154 Aeroplane intended to be non-capsizable, 174 Alabaster, A. W.. 37 Alcohol and yeast from banana meal. 271 • from wood waste in Sweden. 74 on generations of rotifers. Effect of, 278 .Mga. .\ parasitic. 192 .■\lgae, Hrov.n flagellates and brown, 72 , Evolution of. 108 . Life cycle of red. 270 . Photosynthesis in. 108 Alimentary canal and length of body, Length of. lys Amphibians. Marsupial. 440 of the great coal swamps. 348 Angle. The trisection of an. 63. 105, 135, 420 .\nimals. Self-advertising. 41 Announcements. 8 Anstey, KhodaA., 143 Answers, Queries and. 21. 1S5, 267 Anthropological Institute. The Royal, 66 Ants and plants, 150 find their way home? How do, 84 Apophyses of the scales of the cones of the Scots I'ine, The mechanism and use of the, 220 .\quatic vertebrates of Sahara, 160 .\rmitage, Kleonora, 214 ,\rran. (llaciation of North, 34 Arrluiiiinis itixultiiiiis Koen. \'J2 .\rsenic Compounds. Bacterial decomposi- tion of. 151 in vegetable products, 233 .\sher. James. 367 Astronomical Society of Barcelona. The. 58. Astronomy, 21. 136, 185 . Everyman's, 294 Notes. 31. 71. 107, 149. 186. 231, 270. 315, 339. 388, 431, 472 . The New, 47, 119. 176. 462 Auk. Sale of the eggs of the great, 194 Australian Glaciations. 233 Ayrshire, The alkaline igneous rocks of, 342 BACTERIA, IRON, 187 Badges, tickets and passes. The knowledge of metallic, 225 Bagnall. Richard S,. 215 Banana meal, .Mcohol and yeast from. 271 Barcelona. The .\stronomical Society of. 58 Barlow. E. W., 199 Barraud, Phillip J., 166 Bedford, E, J, 251 Bees and green flowers, 432 Benham. Charles E., 125, 137 Bentley, Wilson A., 9 Bickerton, Professor A, W., 14, 47, 119, 176, 220, 462 Bickerton's Theory, The second law of Thermodynamics, and Professor, 361 Bingley, Charles S., 135 Bird break the egg shell ? How does a young. 348 — — flight theories. 80 Bird Protection, Brent Valley Bird Sanc- tuary. An e.\periment in. 437 Bird Sanctuary. — .\n experiment in Bird Protection! The Brent Valley. 437 Birds: .\ comparison. .Vrrival of Summer, 240 , Alleged rudiments of teeth in modern, 242 and genetics, 194 , as seen from a motor car. The flight of. 39 , British, 346 , Egg tooth of, 278 , Extremes of size in. 194 , I'lirther new British, 80 , Ililiernation among. 115 . inland on migration. Wading. 116 in the British Isles, Casual, 157 Birds, Longevity of, 440 , nesting at high altitudes. Common, 39 in England in December, 80 , New list of British. 240 , Recovery of marked. 39, 194 , Reproductive periods of, 477 . Snakes, Burrs and, 13 , Successful protection of, 240 , The body temperature of. 39 . flight of, 135 Bivalves, Boring, 161 . Defences of. 118 Blathwayt, Theodore B., 205 Blow-fly, Sensitiveness of. 243 Books. Brief notices of. 204, 245, 285 Botany at the British .\ssociation, 473 . Notes, i2. 72. 107. 150. 186. 252. 270, 315, 340. 390. 432, 473 Bowell, E. \V.. 191. 239. 343. 475 Bower. F. O., 400 British Association at Dundee. The, 408 , Botany at the, 473 , Ornithology, 396 , Petrology at the, 434 , Stratigraphy at the. 474 Birds, 438 , New list of, 240 Elms, 232 Insects. Some primitive, 215 Broadlev, A. M., 65. 97. 138. 181. 225. 279, 306 Bryophyta, Classification of, 73 Buckwheat seed. The, 150 Bulman, G. W., 449 Burrows. Fauna of. 321 Burrs and birds. Snakes. 13 Burton, J.. 76. 154. 193, 343 Butcher. .Anna Peane. 43. 101 Buxton, L. Halford Dudley, 166 CAITHNESS, VEGETATION OF. 187 Calendar by Gilbert White, .\ Nature, lo INDEX. Camera, A new instantaneous photo-micro- grapliic. ijy Canadian ruffed grouse. The, 295 Canadium : a new element. 109 Carbon monoxide. .-V toximeter for, 433 detector, 33 , Sensitiveness of birds and mice to, 316 Caterpillars, Tenacitv of life in, 198 I avers. Professor F.'. 32, 72, 107, 150, 186, 232, 270. 296, 315. 340, 390. 432, 464, 473 Ceylon : The island of Jewels. 2 Chamberlayne. Tankerville. 7 Chameleon, Warning colour in a. S3 Charcoal, Spontaneous combustion of, 233 Chemical reactions at high pressure, 392 Chemistry Notes, 33. 74,109, 151, 188, 233, 271, 316, 341, 392, 433, 473 — — of India Rubber. Some notes on the, 85 Chert, Origin of Radiolarian, 74 Cheshire, H. F.. 135 Chimney, Cutting down a, 142 Christy, Cuthbert, 13 Chromium, Printing witli salts of, S2 Claremont. Leopold. 2 Closterhini. Structure of, 32 Cobalt oxalate. Printing with, 82 Collecting apparatus, .Y new pond, 394 Colloids, The ultra-microscope and its application to the study of, 217 Comet, Encke's. 32 , Schaumasse's, 32, 72 , The aquarid meteors and Hallev's, 186 Comet's orbit, -V simple method of Bnding the radii vectores of a, 169 Comets, 119, 432, 473 , Meteorites and. 21 Compositae, Discal florets of, 361 Concrete, -Action of acids on, 316 Conroy. Charles C, 137 Consecration crosses. 127 Constellations, Primitive, 205 Cooking. Waste in, 447 Copper nickel ores in East Griqualand, 189 Correspondence. 7, 62. 105, 135, 205, 220 266, 336, 359, 385, 414, 420, 447, 464 Cosmic evolution. Proofs of the Impact theory of, 462 Cowan, H. Hargrave, 266 Cregan. Thomas Ashe, 169 Crofts, D. G.. 64 Cromraelin, A. C. D., 23, 31, 60. 71. 90, 107, 133, 149, 177. 186, 223, 231, 258, 269, 270, 313. 315, 339. 358. 386, 388. 431. 446. 471. 472 Cross, .Vmv, 447 . M. I., 37 Crustacea in Botanic Gardens. Exotic, 42. Crustacean. Interesting adaptation in a burrowing. 84. Crystals. Liquid. 416 , Snow, 9 Cuckoo. The evolution of the, 449 Cuvierian organs. Discharge of, 198 Cuttlefish, I^rge. 41 Cvcad stem-structure, 107 Curtis. John A., 35, 75, HI. 153. 189, 234, 272. 316, 343, 393 DARKNESS. RESULTS OK IMPRISON- MENT IN. 118 Davis, Oliver G. M.. 55 Davison. Charles. 160, 171, 287 Day of the week. To find the, 367 Denneit, Frank C, 30. 59. 89, 161, 198. 200. 216. 250. 304, 312, 357, 361, 399, 441, 445, 470 Diamond, Origin of the, 34 Diatom valve. Further remarks on the true structure of the. 350. 369 Diatoms. The pseudopodia of, 193 Dimension. The fourth, 268, 336, 420 Diopsia. 436 Divining rod. Water supply and the, 152 Documents. Questioned, 210 Dogs. Skin of hairless, 242 Dresser collections. The, 194 Drew, .\ubrey H., 333 Dunton, W. F., 8 Durham barrow, .\., 64 EARTHWORMS, STKANC.E HOMES FOR, 321 Earthquake of 1905, The Indian, 287 ■. The new Madrid. 393 Earthquakes and glaciers, 434 , The origin of, 160 Eclipse, The partial solar, 199 Note on a Paris photograph of the, 269 of the sun. The, 231, 235 Ecology, Intensive, 340 Editorial, 1 Egerton, ..Mfred C.G., 40, 82. 117. 159, 196, 242, 278, 320, 439 Egg-tooth of birds, 278 Electric discharge, .\fterglow of, 117 Electricity, .\ simple device for atmospheric, 125 from heated carbon. Emission of, 117 Electrons during cliemical change. Emission of, 197 Elements. The transmutation of the. 254 Elms. British. 232 Enckes Comet. 32 Encyclopaedia Britannica, Mathematics and Physics in the, 26 Epithelium. .\n alternative silver method for demonstrating the cement substance in pavement. 274 Erosion in the Himalayas. 110 Eruption of Usu-san and the formation of a new mountain in Japan. The. 171 Esam, Wm. Wills. 220 Espin, The Rev. T. E., 17 Explosions, 197 Exposure tables, 40. 82, 117, 159. 196, 240, 277, 320, 347, 398, 438, 476 Eye-piece, A double demonstrating. 275 FAUNA OF IRELAND To THAT ol" THE SPANISH PENINSL'LA. ON THE RESEMBL.\NCE OF THE FLORA AND. 93. 220 Feathers and scales, 242 Fermentation, .Alcoholic, 151 Ferments and fermentation, 179, 207 Fibre, Marine, 33 Fig, Fertilisation of the. 296, 361, 464 Fish life, Eflect of road-surfacings on, 188 Fishes and malaria, 399 , Hearing in, 348 , Intelligence of. 197 , Memory in. 243 , Smell in, 321 Flagellates and brown algae. Brown, 72 Flea, The pygidium of a, 154 Fleas. Glacier. 440 Flies tongues for the microscope. Note on preparing. 474 Flora and Fauna of Ireland to that of the Spanish Peninsula, On the resemblance of the, 93, 220 Florets of Scnccio jacoboea, The discal, 301 Flour and its effect on digestion. Bleaching of, 110 Flower, Evolution of the, 109 Fluorescence. A note on. 117 Flv-catcher. Another new British Bird. The Collared. 115 Focostat lens. The new, 193 Fog, 196 Foods, On Cooked, 381 Force, Gravitational, 117 Fulmar in the British Isles, The breeding range of the. 276 Fungus on leaves and oranges. Sooty, 76 GALAXIES? ARE THE WHITE NEB- ULAE, 31 Galls, Theory of, 161 Galpin, Arthur, 127 Gannet in the outer Hebrides, Winter movements of the, 240 Garnett, Henry, 360 Gave, Leo. L. W.. 127 Geochemistry, The data of, 189 Geologv Notes, 34, 74, 110, 152, 188, 233, 272, 316. 342. 393. 434. 474 of the country around Ollerton, The, 188 Gibbs. G. R.. 63, 136 Glaciation of North Arran, 34 Glaciations. .\ustralian. 233 Glaciers, Earthquakes and. 434 Glass, Devitrification of silica, 271 Glow-worms. Habits of, 321 Gradenwitz, Dr. Alfred. 294 Grant. Edgar. 137 Gravitation, Possible screening action of matter on, 472 Gray, H. J., 165 Greenfinch and Chaffinch. Hybrid, 115 Grouse in Scotland. Willow, 38 , The Canadian ruffed, 295 Gull, The British Black-backed, 270 Gymnastics, The Swedish system of educa- tional and medical, 143 HABITS, FORM.VTION OF, 347 Harmonograph tracings recorded electro- lytically, 20 Harris. David Fraser, 179, 207 Harvest Mite, 435 Hastings, Somerville, 465 Haviland, M.D., 170 Haynes. T. H., 478 Hearths on the coast of South Wales, Pre- historic. 451 Heath. T. E., 267 Helium, Natural gases rich in, 433 Henkel, F. W., 409 Henslow. George, 220, 300, 362 Herbarium in the world. The oldest, 214 Hibernation among birds, 115 Himalayas, Erosion in the, 110 Hind. H. Lloyd, 157 Hooker, Sir Joseph Dalton, 400 Hoopoe in England, First record of the, 194 Horsetail (Equiscliiiii\ Biology of the, 108 Horses, Two-toed, 398 Horticultural Society as derived from con- temporary medals, caricatures, and other rariora, A knowledge of the origin and early history of the Royal, 279 INDIA. Horwood. A U.. 365 lli.»;»r.l. H Aiibrrv I'., J85 IIiiIht John H . S-i') Mull. I'lHlienm nnci HliippinK muacum (or, 17(. Iliiildn. K. Ardron. i'H llyclr»Kcn, (".low in, I<»f> II.I.IMINATION AND UI.TKA MICKO- SCOPIC VISION, DAKK <;l«)I NI). 37 , Dark ground. 43fi of opaque objects wlien viewed l>y the aid of the vertical illumination, .\ppar- atus to facilitate the, 37 linage of fine lines. Spreading of the, 81 Impact theory. The spectroscopic aspect of the, 106. '2J0 Implements. Pliocene I-'lint. 3-4 Innes. K. T. A.. 137 Insect anatomy. 267 scales. The cuneate markings of. 343 Insects' CHgs. 235 Insects. Mechanism of respiration in. 348 . Some primitive British, 215 Institution. The Royal, 8. 453 Instruments in the seventeenth and eigh- teenth centuries : Their trade cards and other rariora. The knowledge of the makers of scientific. 306 Invisible, Photographing the, 116 Ireland to that of the Spanish Peninsula. t)n the resemblance of the Flora and Fauna of. 93. 220 Iron. Printing with salts of, 39, 81 JAMESON, H. LYSTIiR, 421 Japan, The eruption of Usu-san and the formation of a new mountain in, 171 Jenkins, C. E.. 275 Jewels. Cevlon. The island of, 2 Jobling. E.'. 217. 416 Johnston. John. 268. 420 Jones. The Rev. R. F.. 436 Jude. G. \V,. 20 Jupiter's satellites, Tables of, 388 KALEIDOORAPH, THE, 247 Kapteyn's reports on the progress of work on his selected areas, Professor J. C, 315 Keegan, P. Q.. 54. 92 Kernschwarz, 192 Kleptomania, 175 l.AKK DWELLINGS. ENtlLISH. 300 Lambert. F. C, 78. 114. 274. 319 I^minariaceae. Development of. 315 Lavas. British pillow. 152 in the Daldradian schists, Pillow, I.r,T-h \rthnr I. . 1.^1 It: I Is. ,SJ 1.1, .,, ri, ^r.ipiiH 11'/ l.r.in.ird. Frederick I'. . 267. 385 Lichens. Biology of. 150 Life on the Planets. 84 . The subtlety of, 2W without microlies, 327 Light. Velocity of. 21. 62. 137 Lightning, 267 Flashes, 266 , Globular, 343 Limpet, Natural History of Slipper, 398 Liquid Crystals, 416 Liquids on a water surface. Semi-oily, 278 London's water supply. Purity of. 233 Lord. J. E.. 237 Lunar Exhibition. Forthcoming. 58 M.\CNAMARA. CHARLES. 295 Madagascar. The volcanoes of. 272 Magnification. Determination of. 398 Mann. F. P.. 327 Markwick, Col. E. E., 337 Marmol. F. T. del. 405 Marriage. Ernest. 317 Mars. Photographs of . 31 . The axis of. 107 Marsh Plants. 186 Masons' Marks. 127 Masters. The association of Public Schools Science. 70 Matches. Composition of some early. 34 Mathematics and physics in the Encyclo- paedia Britannica, 26 . The romance of. 405 Matter indestructible ? Is. 292 Medals. Of the knowledge of historical. 181 Medicines, .\ncient and modern, 55 Mendelian experiments, 15cS Mendelisin. 185 Mermis family. The, 398 Mesozoic rocks of Kent, The, 189 Metals, I'ositive ions from, 117 Meteorites and comets, 21 Meteorology notes, 35, 75, 111, 153, 189, 234. 272, 316, 343, 393 Meteors. 7. 71 and Halley's comet. The aquarid. 186 , Observations of some recent. 385 Microbes. Life without. 327 Microhydra, Medusoid of. 278 Microscope, .K new, 37, 79 and its application to the study of Colloids, The Ultra-, 217 , Photography with a, 241 tray, ,\ revolving, 78 Microscopical Club, Quekett, 38, 157, 191, 240, 275, 346, 476 Society, Royal, 38, 78. 114, 193. 275, 345, 476 Microscopy Notes, 36, 76. 112, 153. 190, 235. 273. 317. 343. 394, 435, 474 Micro-telescope, A new, 345 Milky way, The distance of the, 431 Mitchell,' C. .-Vinsworth, 33, 74, 109, 151, 188, 210. 233. 271. 316. 341. 392. 433, 473 Mite unrecorded in Great Britain. An interesting earth. 36 Mites. Harvest. 317 Moldenhawer's work : Plant anatomy a century ago. 341 Monadidea. Notes on the development of. 333 Moon in ultra-violet light. Photography of the. 432 Motion* considered on the principle of relativity. Celestial. 337 , Proper, 315 Mouse ace ' How docs a, 41 Music. The study of primitive. 148 Mussel. Discharge of spermatozoa in fresh- water. 161 Mvrmecodia. 321 NAPOLEON. THE KNOWLEDGE OF THE DEAD. 97 , living. 138 Naturalist. The Scottish. 80 Nautilus : Some homologies between the I'ossil and Living forms, The Pearly, 365 Nebulae galaxies? .\re the white, 31 , The spiral, 409 Nebular distances. On stellar and, 329, 373 Nepheline syenites of West .\frica, 110 Nesting. Commensal, 39 Net, Self-closing plankton, 42 Nevada. Minerals of Tonopah, 272 New Ze.iland sand dunes. 1,S6 Nicotine in the tobacco plant. Variations of. 433 Nitrates from the atmosphere. Preparation of. 342 Nitrogen. Active. 242 in wheat. Distribution of. 392 Notes. 31. 71. 107. 149. 186. 231. 270. 315, 339, 388. 431. 472 Notices. 42. 84, 124. 137. 164. 205, 222. 246. 286. 298. 326. 368. 380. 448. 480 NovaGeminorum. 176 OBSERVATIONS, 1912, MISCELLAN- EOUS, 266 OHalloran, Sylvester N.E.. 361 Oils, including an account of the materials and methods of perfumery. Notes on the Essential. 454 Ophioglossales and Marattiales. 390 Optical convention. 1912. The. 291 . Proceedings of the. 319 Orchids and their fungus guests. 473 . Some rare Sussex, 251 Ornithology, 137 at the British .\ssociation, 396 Notes. 38. 80. 115. 157. 194, 240, 276, 346. 396, 437 Oxalidaceae, Leaf-movements in, 432 Oxygen, Production of solid, 74 Oysters, Purification of, 197 PAINTS, TOXIC .\CTION OF OIL, 341 Parallin oil from a Yorkshire coal-seam, 110 Parakeet, The fate of the Carolina. 115 Parasites of pitcher plants, .\nimal. 473 Parsons. The Roval Microscopical Society. Presentation to Mr. Frederick .\., 275 Particles. The counting of a. 440 Pearl-making. 160 Pearling Industry. Biological science and the. 421. 47S' ixni-.x. Pearls and parasites, 399 Peat deposits. Scottish. 391 for power purposes. Use of. 433 Penguins breeding. SO Peregrine. A conveyed. 116 Perfumery. Notes on the essential oils. including an account of the material and methods of, 454 I'erkins. Frank C. \-iZ, 1()S. 174 I'etrology at the British Association, 434 I 'harmacopoeia. .\n Irish, 170 Phosphorous. Red. 392 Photoelectric fatigue, 117 Photographic image. Reversal of the, 276 printing papers. Spots in. 395 Photographing coloured objects. 476 Photographs. The eflect of damp on, 195 Photographv Notes. 39. 81. 116. 158. 195, 240, 276, 319. 347. 397. 438, 476 Proceedings of the Optical Conven- tion, I. Colour. 319 Photo-micrographic apparatus. .\ universal geometric slide. 1 15 Society. The. 79 micrography at a low magnification. 241 equivalent exposures, Low power, 273 for naturalists. Low power, 77 lighting and back-grounds. Low- power, 317 of opaque objects, 438 , The use of projection oculars in. 319 with high powers. 397 medium powers. 347 without a microscope. Low- power. 112 Photosynthesis in algae. 108 . Potassium and. 270 Phthisis. Rainfall and. 36 Physical laboratory. The National. 321 Physics in the Encyclopaedia Britannica. Mathematics and. 26 year 1911, 41 Notes. 40. 82. 117. 159. 196. 242, 278, 320. 439 Pictures and prints. A knowledge of naval, 65 Pigeon, The last of the Passenger, 115 Planet M. T, 270 , The interesting minor, 231 Planets. Life on the. 84 Plant anatomy a century ago, Molden- hawer's work, 341 Plants. Biology of salt-marsh. 271 . Naked-eye anatomy of, 271 , Origin of vascular, 340 Pocock, L. C. 356 Polar phenomena, 21 Polydacivlv. 198 Poole. Hubert H. 16 Porpoise. \ white. 440 Porthouse. William. 59 Potash in the United States, The search for. 342 Potassium and photosynthesis, 270 in plants. 150 Potter, C, S. 267 Proctor. Mr. Robertson versus Mr.. 8 Proof plates, 320 Proteins, Vegetable, 315 Protura. The. 215 Psochid. Web-spinning, 321 Pump, An improved Toepler, 165 Pyroticmu, Life history of, 391 QUEKETT MICROSCOPICAL CLUB. 38. 157, 191, 240. 275. 346. 476 Queries and answers, 21, 185, 267 RADIO-ACTIVITY, 196 active bodies, 195 Radium. Alloys of. 271 in the waters of Bath, 188 Raffety, Charles W., 106 Rainfall and phthsis, 36 of April. 235 Rats. Reproduction of brown, IIS Rays, Sterilisation of water by ultra violet. 33 Reactions, Photographic effect of chemical, 109 Redgrove, H. Stanley. 85. 254, 292. 336 Keed warbler. The great. 346 Research Defence Society. The, 96 , Special appeal from the. 360 Reviews, 27, 67, 124, 162, 200, 243, 260. 322. 362, 406, 442, 480 Aeronautics, 27 .\rchaeology. 200 .\strology, 243 AstronoiTiv, 201, 362, 406 Bacteriology. 260. 322, 363 Biochemistry, 442 Biography, 407 Biology. 67, 260, 363, 407, 442 Bird Migration, 162 Botany. 202. 261, 322 Chemistry. 27, 67, 162, 262, 407 Cosmology. 363 Crvstallography, 68 Evolution, 28, 243 CJeographv, 28 Geology, 29, 162. 263. 324 Heredity. 324 Horticulture. 443 Mathematics, 163. 325 Medicine. 68. 244 Metaphysics, 407 Meteorology, 163, 325 Microscopy, 124. 244 Mineralogy. 69. 364 Mycology. 443 Natural History, 364 Oceanography, 444 Ornithology, 29. 203, 364 Photographv, 480 Physics, 69,' 163, 203. 325 Prehistoric archaeology. 164 Psychical research. 264 Psychology. 124. 164. 444 Topography, 444 Tides, 29 Zoology, 69, 164, 245, 264. 444, 480 Robertson r'ccsHs Mr. Proctor, Mr., 8 Rock associations. The invariability of, 152 Rockling. Vibratile fin of the. 477 Root nodules in non-leguminous plants, 340 Rosaceae, The " calyx-tube " of, 108 Rotifers. Effect of alcohol on generations of. 278 Royal Institution, The, 8, 453 Rubber, Some notes on the chemistry of india, 85 Kyves. Reginald, 377 SAH.VRA, AQU.\TIC VERTEBR.\TES OF. 160 Salamander, Colour change in. 348 Sand dunes. New Zealand, 186 Saturn. 445 Scales. Feathers and, 242 Scharff, R. F.. 93 Schaumasses Comet, 32, 72 Scotland, Willow- grouse in, 38 Scots Pine, The mechanism and use of the .\pophvses of the scales of the cones of the, 220 Scottish peat deposits, 391 Screen, A blue, 343 , .\utochrome, 278 Sea, Resources of the, 197 Sickness, 267 squirts. Edible, 398 urchin. Locomotion of. 348 urchins. Hybridising, 198 psdicellariae. Sensitiveness of. 118 Seismology Notes. 160 Selaginella. Biology of. 271 Selborne Society's conversazione, The, 76 Sciiccio Jacobocut , The discal florets of, 301 Senior, Edgar. 39. 81. 116. 156. 195, 240, 276, 319, 347. 397. 438. 476 Sense. The graphic expression of. 43, 101 training, 349 Shepherd's purse. Mutation in. 72 Shrews. British fossil. 41 . Teeth of. 321 Silica. 82 Silicon, Amorphous, 151 Silk. Eri. 399 Moth. Origin of germ-cells. 160 Siloxide. a new glass, 151 Skeleton in glacial deposits at Ipswich, Human, 23-* Sky, Brightness of the background of the, 339 Sky. The face of the. 23, 60, 90. 133, 177, 223, 258, 267, 313, 358, 386, 446, 471 Slack. H. F., 454 Smith. T. F., 350, 369 Sniyrnium. Fruit of. 190 Snail see ? Does a. 42 Snails. Locomotion in. 278 Tongues for the microscope. The pre- paration of. 237 Snakes, burrs and birds. 13 Snow crystals. 9 Soar. Charles D.. 192. 436 Soil and the plant. The. 232 Solar Disturbances. 30. 59, 89, 161, 200, 216. 250. 312, 357. 399, 441, 470 Soot, The composition of, 74 Sos, Ernest, 105 Spanish Peninsula, On the resemblance of the flora and fauna of Ireland to that of the, 93. 220 Spectra. 242 Absorption, 439 Resonance, 439 Spiders. Body poison of. 243 Squire. D. S. B., 205 Star, A new, 150 charts. How to make stereoscopic, 221, 267 , Stereoscopic, 359 drifts, Prof. Turner's suggested ex- planation of the two, 270 in Gemini. The new. 186 Starfish, Self-evisceration in a, 440 Stars, Spectra of faint. 339 with common drift. Groups of. 71 Statue, .\ colossal reinforced concrete, 168 Stellar and nebular distances. On, 329, 373 Sterilising soil, Effect of, 473 Sting-rays of the Ganges, Freshwater, 399 Stonyhurst college observatory, 198 Stork (Cicoiiia alba) nesting in captivity. White. 276 Strachan. James, 345 Stratigraphy at the British Association, 474 Strickland, Sir W. W., 301 Struggle for existence. Inter-specific and intra-specific. 83 Stuart. A. H.. 221 Suherites and Dromia, Association of, 42 Sulphur. Fertilising action of, 233 Sun and its effects on vitality. The, 8 , The, 47 Sundew, A British insect-eating plant. The, 166 Sundials, Saxon, 127 Sun's path in space. The, 136 Sweepings, 62 INDI.X. TADl-iX.KS IN si:.\ \v,\Ti:n. K^ 1 >sl .: |.; Wilfrc.!. .M7 I i.ii n . r 1 • !■ r iiliv. A liricf matlH'mnlii-.'il loiicepiiiiii of. JS<. Telescope*. The nccil for, 7 T.iii|«i.,iui.- I .iii.iiiiriiil, (.t I MM . riic .^tcond law of. J61 Thcrmostais. ^0 'Ihunison. I) il,-ilt.iny. Limited), by Joil.N King, Kaling and U.xbridgc. Knowledge. With wliicli is incorporated Hardwickc's Science Gossip, and the Illustrated Scientific News. A Monihlv Record of Science. Conducted by Wilfred Mark Webb. I'.L.S., and !■:. S. Grew, M.A. lAMARV. I'JIJ. EDITORIAL. In answer to the reiiiii : and \(.ry rarely only, the miner.d is tound green in the island. In (enlral Oueensland. how - rxcr. at a place called .\nakie. the ^r< 111 \ariet\' is fairK- plentifu" wiiilc the red and ])urple are entirely absent. Some of the corundum gem- stones exhibit the phenomenon of ii.sfcrisiii. that is, they display a bright shimmering six-pointed star with the ravs divergent from the centre of the stone when it is lilt with a smooth convex surface. They are found almost exclu- si\ely in '."eylon (a few ruby star- stones are found in Burmah), and under the name of tf.sYt'r/tf.s- or .s7<7r-.sYo/it'.s are highh- valued by connoisseurs when of choice quality. I'or some unknown reason, the yellow and green varieties of corundum do not exhibit the |)henonunon of .isti-rism, .Vnother gem - mineral which FiGL'KE 3. Crystal of Jaigoon or Zircon (actual size). Wlifii cut as facetted stones, jarsjoons possess the power of ilispersiim of liglit approachint; in some cases to that of the diamond. 1 U.lKl. Crystals of Alexandrite uctiial size). riie aleNaiulrile and cat's-eye are both varieties of the mineral clnysobervl. and in very rare cases the cats-eye \ariety also possesses the power of alteration of colour. Although Ceylon is the chief source of the alexandrites and the sole source of the cat's-eye, the most choice specimens of the former are derived fromSiberia. These jjems are almost colourless and transparent bv transmitted lijilit. but display when cut with a smooth convex surface (en cil'n. Iii.iit n i>l,ii, ,„■ 1,1, 1, .,1) Mr,.,], ,,t v;„,i iri.ni v>'.i.h iliev take their name. KNoWI.l.DCl-: 1 IGLKL /. The " geiiiining " basket in use. possesses a similarly extensive range of colour, except that vellow i? missing, is the spinel. Some specimens of this, somewhat resemhle rubies and sapphires, and are therefore often described as " spinel rubies," and "spinel sapphires" respectively. It is, however, verv much softer than corundum, and is one of the three gem-stones, occurring in the form of crystals, which are singly refractive, the other two being diamond and garnet. There is a remarkable Hame-red variety of spinel, the colour of which is unique in the whole mineral world, not even excepting the ruby. It is an exquisite gem of great value. The chrvsoberyl is an attractive gem stone. although its heautv is somewhat unappreciated. It occurs in shades of Autumn green, brown, and vellow, and possesses great brillianc\-. There are, however, two varieties of this gem-mineral which form well-known and valuable [jrecious stones : of these, the most important is known as the alexan- drite. (See Figure 4.) Fine examples of this gem by daylight appear pistachio-green, changing to rich mulberry-red by artificial light. Cevlon is the chief source of alexandrites, although a few are found in Siberia. The other important variety of chrysoberyl is the cyniophaiie or cat's-eye, which, when cut with a smooth convex face presents a narrow white line glittering across it, which has a fancied resemblance to the iris of a cat. The position of the line or rav alters as light strikes it from different angles, giving a [x'culiarly mysterious effect. Cymophanes are only found in Ceylon. The rarest and most curious of all precious stones are those cat's-eyes w hich change from green to red, as do the alexandrites. The basket is handled with a eircular movement. riic hyhler stones shp over the edge of the basket. JWUAKY, 1912 KN'n\vLi:nGE By the siii)crstitious natives tht- cvmopliaiic is considered to be an entombed spirit, and this can l>e more readil\- understood than many other similar conceits, because of the strange resemblance of the stone to the eye of an animal. Many shades of soft yellow, brown, cinnamon and green are displa\ed by specimens of the mineral jargoon or zircon. (See Figure .5.) This gem-stone is strangely unappreciated, for not onlv is the colour- ing most pleasing, but the brilliance is second onlv to that of the diamond. Another reason why the neglect of the zircon is unaccountable is that this beautiful gem is comp;irati\i Iv iiu-xiien- si\e. The w liter has onl\- sjiacc brielK' to complete the list of precious stones of Ceylon, for his object is to give the reader some idea of the manner in which thev are handled. There are garnets, red. brown, violet and cinna- mon : topazes, white and blue: tourmalines, red. claret, green, yellow and blue ; aquamarines or beryls. sk\-blueand sea- green : besides iolotes and moonstones. (See Figure 5.) From the foregoing paragraphs it should be apparent that these gems present a pageant of colour unequalled by those of any other district. From the finding of a precious stone in a ri\er- bank or gem-pit, to its use as a jewel b\' a woman of fashion, it passes through many strange hands, and undergoes much alteration in appearance. The securing, cutting, polishing and marketing of such a large number of gems necessarily com[)rise an important industry. The entire trade is controlled locallv b\- the Moormen, man\" of w bom are extremelv wealthy. The foremost of them not onlv bu\- up the most important stones as they are found from time to time, but send out expeditions into the [irincipal gem- producing areas to search for them. They all either retain their own cutters or superintend the work gi\en out to be done. No foreigner is admitted within the magic circle of the Moormen e.xcept as a customer. The Moormen are descendants of the Moors who once occupied Ceylon, and of whose forts large ruins still exist in the island. The value of the precious stones annualK' exported to Europe and America from Ceylon is estimated at three million pounds, and high prices, esi)ecialK' for choice specimens, are realised locally from travellers and tourists. The gem-stones are of igneous origin, and have I'iGU Native gem cutters at work w been loosened from the granite and gneissic rocks in which they were formed, by disintegration. They are found in a stratum of alluvial gravel which is know II to the natives as " illam," which is reached by digging pits of from three to thirty feet in depth, The\' are generalK- in the form of more or less water- worn nodules, undamaged crystals being very rare, (See Figure 2.) When the pits arc deep, the illam is hoisted to the surface by means of a primitive kind of wooden crane (see Figure 1), and it is then carried to the nearest stream or jiool to be washed. It is often found, in low-lying spots, that old disused gem-pits which ha\'e become filled with water, are available for the washing of the gcm- licnring material. The illam consists of :r;L\-el embedded in \ rllow or reddish cla\', and is usually lirought to the surface in a dr\- rrindition. but when the ;-:iin-pit is below tlli> lc\el of a neighiiouriiig streatn, it is rather muddy. Sometimes the st la- tum of illam crops out. or is exposed upon the surface of the countrj-, and this is generally slopes and banks of Kli 10. ith the overseer watching them. the When this is the case, \'er\- done, as the material is more found to occur on ri\ers and streams, little excavation is easil\- obtainable. The searching for gems is carried on from October to March. The washing is done by means of a circular basin - shaped basket, about twenty-eight inches in diameter and twelve in depth, which is called a '"gemming basket "" : the native wading up to his knees holds the basket in the water. (See Figure 7.1 .■\ circular turning movement (sec Figure i>) is given to the basket, which is occasionally allowed to tilt below the surface of the water, and in this way the lighter stones slip over the edge, and the heavier ones remain in the basket. (See Figure 9.) .\fter a good many baskets full of gravel have been washed in this way. the residue, which is found to contain thorianite and thorite and other heavj' minerals, is carefull\- searched for gem-stones. The number of gems found of insignificant value is extremel)- large in proportion to that of the choice specimens, so that often a great deal of work is done before there is any prospect of recompense. When an important stone is discovered there is great excitement among the natives, and many would-be buyers eagerly endeavour to outdo each other in obtaining a bargain. The price asked is KNOWLllDGi: January, 191. HcntTally si-vcral tiinrs ^r'atii tliaii llial wliiili is (.'ventually arcrptiii. and In contiiinal haiUiiiin. llx Rem cliaiiRfs liaiids repeatedly. Also, tlicrc are ever refidy pilferiiif,' lin^'ers to I'KILKi; 11. A Moor L;ipidary, Ceylon. purloin Iroiii tlie rij^'htful owner, or to substitute an inferior stone for one of good quality. The diggers and washers are continualK- watched to prevent anything of the kind from taking place. It is a matter of great difficulty for Europeans to obtain details or photographs of the gemming industry, for the natives are verv jealous and secretive, and object to company upon their e.xpeditions. They are also exceedingly super- stitious, and beliese in all sorts of devils and evil omens : they will not even allow one of their own women to go near a gem-pit. becau.se she would be sure to bring bad luck to it. There are several extensive districts in the island where precious stones occur, but the most productive localitv is the hilly country of Saffragan. the chief town of which is Katnainira. or in other words " the city of rubies.'" Nearly all the different kinds of gems arc found occurring together, the excejitions being moonstones, amethysts, and alexandrites, the last of which are principallv derived fiom (ialle. The natives have a great jireju- dice against sending gems out of the island in the rough state, and alwass cut and polish them locally. This is due to iheir an.M' ' il\ to what extent the beauty of each .-.luuc i.s tlcveiu|)ed by tile cutting, and thus accurately to estimate the value. They do not care to part w illi the rough stones, for liuropeans to reap th(; benefit r)f .any increase in v.ilue. The cutting and polishing is done bv the Singhalese upon |)erpendicular leaden wheels, smeared with emery, against one side of which the gem is jiressed with the left hand, while the w heel is rotated bv means of a bow and cord heW in the right. (See Figures 10 and 11.) The whole apparatus is most simple and primi- live, the success of the work de- [lending entirely u])on the skill of the o|)erator. The cutters S(piat ujion their haunches behind the wheels, and sometimes an overseer watches the progress of work to prevent theft. (See Figure 10.) Much of the cutting is done by the roadside in view of every passer-by, but many little " tricks of the trade" are withheld from public view. The native gem-cutters" chief object is to so manipulate the precious stone that the maximum of size and weight is retained, often to the sacrifice of symmetry and brilliancw The\- are wonderfully adept at retaining and regulating the colour, which in some gem-stones is not of uniform density throughout. and in dexterousl\- hiding feathers and Haws. Owing, however, to irregularity, and also tile want of .symmetry and proper proportion, it is Tlir gems of Ceylon arc rcciit in Europe Jamauv. lOlJ. KXfnVLl-.DGi:. ,'enerally found that the gem-stones in the " native- diamond dust, and revolves horizontallv instead of cut " condition are unsuitahle for tlie re(]uirements of liigh class European jewellery. It is therefore necessary, hefore the\" can be used for the purpose, that the\' shall he re-cut by a skilled lajiidarv with a knowledge of mineralogy and optics. In principle, the apparatus used hv the Euro[)ean gem-cutter is similar to that used by the Moor in Cevlon. The wheel is, however, made of copper and perpendicuiari\- (see h'igure li). The operator sits at a bench and [)laces the gem, mounted on a small ebony holder, against the surface of tile wheel whicli he rotates b\' means of a crank held in the left hand. .\lthough the apparatus is simple, much expert knowledge, skill and experience are re(|ui3ite for success in this delicate and artistic craft. C()KK1-:SP0NDENCE. THE Nl-:En FOR TELESCOPES. To flic Editors of " KNOWi.i:i)r.K." Sirs, — 1( is indeed strange, as Professor Hickcrton observes, that .Astronomy lias not a greater hold on the human mind. Hut perhaps the general public are not altogether to blame for their neglect of that glorious science. Compare, for instance, the facilities enjoyed by townspeople for literary study, with the opportunities given them to use a good telescope in conjunction with star maps and te.\t books. Where can the " man in the street " go to feast his eyes on the clusters so eloquently described by Professor Bickerton ? Years ago I was young and n.aive enough to ask if I might go to Greenwich to look through the Observatory telescope. I can well iniderstand that casual amateurs would interfere with investigations at the great centres of ob.servation. Hut. surely, reading rooms, libraries and village clubs here and there might be provided in an upper floor with a 4'.-in. telescope, imder the care of some responsible person in the neighbour- hood, who would instruct an attendant. Wanted, then, a scientific Carnegie to provide telescopes. No doubt that the taste for star-gazing is growing, and that the Daily Telegraph reflected general interest in publishing monthly charts of the sky. Professor Bickerton's shepherds and. I would add, fishermen, would appreciate, even more fully than they do. the beauty of the heavens, when they learnt to identify groups in single stars, and could follow their motions. I'heir educated friends should pass on some elementary knowledge to simple people by the only sure methods, namely, by pointing out constellations in stars when opportunity offers, and especially drawing attention to their changing positions as time goes on. , ,, ,, Waui;ham. mi:teors. To the Editors of " Knowledgi;." Sirs. — Will you allow me a little space in your valuable paper in which to make an earnest appeal to all amateurs who are iTiterosted in meteoric observations ? Too little regular work is done in England and. with the successful example of Mr. Denning before us, we in this country who are at all enthusiastic in the matter, might do much work that would be \aluable if only we undertook to systematically watch the sky and furnished full reports of our seeings to someone qualified to investigate them. For many months past my husband and myself have observed every fine evening at regular hours and sent in frequent reports to Mr. Denning with whose results we have had many interesting accordances. Unfortunately as he i.^ not well now and his work limited, many of our observations are of little use. as of course it is only by two observations of the same meteors in different places, that any accurate knowledge can be obtained of their real paths. Will some amateurs who care about this branch of astronomy agree to watch regularly, evening by evening, at stated times, and send us each week or month their records, which we can then conipare with ours and write out both together and send to .Mr. Denning or some other authority. If two li,>urs or more are too long the time could be divided. and each observer have perhaps half an hour or so. we could easily manage to arrange in a way suitable to everyone's wishes. It is such interesting work 1 .All day long I look for- ward to the silent hours when our watch begins, the stars seem no longer far-away twinkling lights, but intimate friends, and each moment is filled with the glow of anticipation as to what grand meteor will next appear on the scene. In our observations we record the times, magnitudes. Right .Ascension and Declination, of appearance and dis- appearance, direction of flight, details of colour, train or trail, and so on. If any of those who, after this appeal, consent to watch, do not care to spend time in determining the Right Ascensions and Declination, or the altitude or azimuth, the name of the star where the meteor appeared to come, and the one where it appeared to go to. will be quite sufficient, if they will kindly mention the name of the star atlas tliey use. as some of the smaller stars have dift'erent letters or numbers in diflbrcnt maps, and it might be diflicult to trace them. Mv.uldress is — Zavijava. Hansol Road. Hcxley Heath. F1AMM1".TT.\ WILSON. TO FIND .VPPROXIMATELV SIDEREAL TIME. To the Editors of "Knowlkdgf.." Sirs, — May I add a post-script to my letter of November giving the eeiuation R..A. = h + 2 m + 5 as an approximate index to Sidereal time ? .As a practical application of the equation I have marked on my watch-dial +0 against IX, +6 against XII, and +12 against III to remind me that on 22nd September Sidereal and clock time are the same, and that in December the dift'er- ence is six hours, and in March 12 hours. LVXDHURST. FK1:D B. TAYLOR. IHrNDFRSroIvMS. To the Editors of " Kn-owi.edgk." Sirs. — I have been for a great number of years a very careful observer of Thunderstorms and Electrical Phenomena in this and other countries, and possibly some day I may trouble you with a few of my notes. But I write now to put a question to your readers which is perhaps more amusing than scientific. Inasmuch as the world is round and thunder- storms like everything else have a beginning, it follows that the first flash of lightning in any storm must be directly over somebody's head. How is it then that we cannot meet with anyone who remembers anything of the sort ? We are in- variably told that distant thunder was heard, or, if by night, distant lightning was seen near the horizon, and the storm gradually approached. The Times, in de.scribing a storm in London, always begins in this wa> — " Heavy clouds were observed in the West and a little later distant thunder was heard, and at such and such a time the storm broke over London." This, too, is the way local newspapers always describe storms. Considering how common in the late spring thunder showers are. it seems strange that wherever we are they always make their first appearance in the distance. tanki:rville chambi:rlayni:. WiNCIIKSIl k. KNoWIJlUCli:. January. 1912. MK. UoHl KISON ixrsiis MK. I'KlK lOK. To the fiililnrs o/ " Knowi.iuigk." Sirs. — Many of your rraiU-rs will cjniibllcss hi- iiitercsiti'd to learn that Mr. John M. Uolwrlson. M.I'., in his " Lotlc-rs on KcasnninK." claims to have shown that llu- fonndcr of this jonrnal "falls into pnro alisnrdity" in his exposition of the ni.'ithcniatical theory of rrobahility. I have written to him privately pointing oiil tlial his .irKnment is foumletl on a iihmder due to a earelessness that is very inappropriate in dealing with an eminent man of scienci-. ami nr^^iiifj that his book should lie provitled with an erratum slip doiiiK jnslici' to Mr. Procter; but his reply makes it clear that he intends to leave his book as it sl.inds. and I therefore trust that you will allow me to deal with the matter in your columns. In No. \'II of his "Letters" above referred to. Mr. Kobertson cpiotes Mr. I'roctor's statement that in the in.iny thousands of experimental coin tossin^s by HntTon and others, a succession ot twelve he.ids (which fretantl\ shifting tnil\. led us. wliilc \it in our "teens," to begin a most enthusiastic and comprehensive study of these marvellous crystals. i'liis has been continued i\er since, for now over a quarter of a century. During this time we have secured many thousands of photo-micrographs of the various forms of water, snow, frost, ice, dew, and so on — two , lu thousand of snow crystals alone, no two alike. Our location. Jcriciio.N'ermont. U.S.. \.. fortunately, was very favourable, as it lies in the path pursueil In- most of the general storms crossing North America. This doubtless largel\- cx[)lains wh\- the snows of our locality are so \-ery rich in perfect and beautiful snow forms. Winters were found to var\ greath' in jjroduc- tivity. some being much more faxour- able than others. Some w inters fui nishcd verv few \x-i- fect crystals, but in general we were able to secure and photo- graph from oni hundred to two hundred perfect forms each year to add to our collection. It is [irobable that favourable winters occur in cycles: but more data, covering a longer period, needs to be collected to make this a certainty. Only one storm in about seven, in our localit\. furnished Jani'aky. 1912. KXOWLF.Dr.i:. I- II many jjcrfcct talnilar forms aiich as we rwjiiired. It is IRDS. Bv CLTH1U:RT tHRlSTV. M.r... F.Z.S. Figure 27. The Khinocero; Whilst exploring one of the big forests in Uganda in 1907, I one day told my men that I wanted some puff-adders, two species of which {Bitis iiasiconiis) (see Figure 27), and a much larger one {Bitis }>iihoiiicit) . are v'ery common in these forests. Next day I had three or four brought to me. and the following tla\' several more. My in- tention was to collect a quantity of the venom. and ultimately preser\e the skins. These dangerous snakes are fortunate]\ sluggish brutes, very un- like most of the Indian ones. The largest species, which is some- times five feet long, is usually found curled up amongst the dead leaves on the ground, where it may, appar- ently, remain for weeks without moving. I have seen a hundred men in line tread within a foot of one without its taking any notice. Both species have the the power of puffing themselves '>ut. when irritated, to more than double their usual girth. and can strike w ith tremendous force. The smaller and horned one is more often found - ' 4»ji jirrs :imongst the undergrowth, a C^ d!-^' ! -^^ considerable distance from the ground. The facility with whicii my men procured a number of these poisonous \ipers surprised me. On questioning them one said something I could not understand about "birds in the grass": so next day I went with him into the forest, telling him to take me to where he had found the snakes he had brought. On reaching the [)lace, he pointed out some clusters of a small climbing plant' a few feet off the ground, and not unlike the common woodbine of our hedgerows. On closer ■j .■/'. S. iScn-i./sc, F.X.S. Viper" (Bitis nasiconiis). A II.'^ FiGUKi; 28. Burr of Pisoiiia iiciilctita. luiik'lli is tweKc iiiilliiiietcrs. e.xamination. I found that the withered parts of this plant bore hundreds of small fruits or ■"burrs" (see Figure 28), which clung to m\- coat sleeve and almost anything that touched them ever so lightly. I was still unable to imagine what possible connection there could be between this plant or its fruits and the snakes: but sure enough we found two puff-adders, and saw- other snakes beneath this mystifying plant, al- tliough to see a snake in tile African forests is not such a \ery common occurrence. On returning to camp and going into the matter with an interi)reter, I was forced to the conclusion that the plant was able to catch small birds, or at least to so hamper their moveinents if its " burrs " became entangled in their feathers that they fluttered about on the ground and became an easy prey to the snakes lying in wait beneath, though it seemed crediting the reptiles with extraordinary perspicacity or even some amount of botanical knowledge. Some months aftiT this, one of my Furopean assistants lirought me a bird about the si/e of a sparrow which he asserted he had caught in the forest with his hands, and which had its and body feathers so matted and tangled these very same " burrs " that it could < more than flutter about the floor. So that it must be really a fact that these snakes have sufficient in- telligence to distinguish in some wav either the ])laiit or the locality in which it grows, or else have learnt b\- experience that that precise spot is one in whicli small birds, so hamper in their movements tliat the\- are unable to fly away, arc likely to be found. In Africa the forest natives are full of little items of observation, such as this, that delight the iield-naturahst. wmg witli Figi:rk 2'J. .A section of the Burr showiiij; the Unobs with which it is provided. Mr. Haynioiul Ditmars, author of "Reptiles of tlie World." says on pajje J27 of his l)ook that the Rhinoceros Viper is the most beautifully coloured of all snakes. This is his description of a specimen which has recently cast its skin : — ■ Knlire upper surface preseiiliiis lhcv land .ind narrowly bordere.! wilb the same hue. The blue oblongs are set in jet black rhombs and these in turn are bordered with dark carmuic. Sides, witli large, upright, ruddy.brown triangles, bordered with dull carmine, thence witli bl.ack and externally with pale blue. Between all of the blotches and pronounced markings, the ground color is rich olive, thickly peppered with black. The he.id is bluish, with black dots, and ornamented in the centre with a sooly-bl.ack arrow.sh.iped blotch pointing forward ; the horns are yellow." [Eds.1 t Dr. Otto Staps has kindly identified it as Pisouia aciilctita (Order Nyctaginaceae). U I'Uoi'i'SSoK A. w. i;uKi:K'r()X In till- belief that many readers of " KNu\vl.i;nc.l-: " \vlu> have studied the recent articles on "The New Astronomy.'" In Professor A. W. Hickertoii. wdiild like to know something ahont tiie career of this (■a|)ai)ie expounder of a new theory of the uni- verse, the few foilowinn facts li;i\i- 1m( n follii t(il. They will explain ln)\\ it iiap|Hiis that the orif,'in- ator of such an epocli- niakinfj discovery has remained almost un- known in British scientitir circles, whereas had his life-work lain in tin home country his naiiu would have been familiar in our mouths as house- hold words. .Mexander William Hickerton comes of an old Cheshire stock and was born at Alton. Hampshire, in 1 N4_'. l)rauj;htsmansliip is a characteristic of his family: his father at the age of fourteen won tiie silver |)alette of tiie Society of .\rts. and later practised as an architec- tural draughtsman: while a son of Professor !>ick- erton is an artist. liducated at Alton (iranimar School and in- tended for a civil engineer. Hicki'rton entered the Bridgwater Carriage Works of the Bristol and lixeter Railway. Inventi\-eness soon appeared and in lt>64. having devised some machinery for wood -carving, he secured a mill in Painswick, Gloucestershire, in w hich to develop his ideas. .\t this time some science classes were being started in the neighbouring town of Stroud and young I^ickerton attended these, at the end of the session gaining a first class and the national bronze medal in the Science and .Art exam- ination. Being attracted to a scientific career by the enthusiasm of the teacher, he applied himself more closely, and the following vear gained further suc- cesses in magnetism, electricity, and animal and vegetable physiology. In 1866 he migrated to Birmingham, and while studying for his science teacher's certificate organised and taught in evening technical classes in that city. His workshop ex- perience enabled him to tittract artisans to his classes and the\' became most successful. ,\t this time the ri-gulations of the Roval School of Mines were altc red an\ |iri\,ile -tudv liickerton was able not onh' to i)ass. but also to secure a Koyal Lxhi- bition. and that in a year when the competition was unusually severe. He won three national medals and seventeen yueen's prizes, of which six were first prizes, in \arious subjects. For the next three years he studied at the Koyal School of Mines and the Royal College of Chem- istry and utilised his evenings in organising evening technical classes in London. He was actually the hrst science teacher under the Science and .Art Department who succeeded in London Iter some scores had iitemiJted and failed. It was his classes that originated the gigantic technical educational scheme among the Lon- don working classes, and in 1S70 Sir Henry Cole, before the Royal Com- mission on Scientific Edu- cation, spoke of him as "a great organiser." In the same year an incident is related by Sir Ceorge C. T. Bartle\', Bart, in The Joiiniiil of f/ic Sojicfy of Arts, that accounts in some degree for tin- phenomenal success of these classes througii the enthusiasm engendered in the students bv Mr. Bickerton. .A school was started in .Arthur Street. Chelsea, and the jiremises proving inadequate, others were taken in College Street. These consisted of a disused carriage factory, and funds to fit them for a regular science school being lacking, the students themselves undertook the whole labour of building a lecture amphitheatre with smaller class rooms under part of the raised seats. Carpenters, gasfitters. white- washers, and other artisans came night after night from six o'clock to eleven and even later. The task took six weeks, and so anxious were the workers to finish it and to resume their classes under Mr. liickerlon that tln'\ could liardK be got awa\- each Bickerton Jam-akv. 1>)1. KN()\VLi:i)Gi:. evening until tin pkm of lowcrini; the gas [)ro\ed cftcctual. Under tile ciiairmanship of the late Sir Ciiarles Dilke, these classes rapidly secured upwards of a thousand students, and became the largest and most successful in the kingdom ; while, in S|)ite of this heav\- extraneous work, Mr. Bickerton was attaining unicjue success at the Ko\al School of Mines. .-\t the end of his tirst year he won the Senior Royal Scholarship, with l()()"u of marks in four subjects, and an aggregate of 98% in all — this against such ties consenting to all tlie conditions formulated by him as requisite before his acceptance. .Accordingly he went there in 1874, and there he worked until 1902. teaching chemistry, electricity and physics, acting as Government analyst, and incidentally giving many public lectures, both technical and popular. His researches have resulted in great pecuniary advantages to the Dominion's industries in many directions. It was the ap[)earanceof No\a Cygni in 1877 that first strongly directed Professor Bickerton"s atten- FlGLKL Jl. riotcasui liickciluii'b lluinc. \\ ainoni ParL. Cliiistcluucli, -New /ual.iiiJ. comi)ctitors as Professor Sollas, Principal Garnett and Professor Liversidge. Completing his cour.se at the Roval School of Mines and the Royal College of Chemistry he obtained the highest class in all save one subject. Many good offers followed, and he took charge of the science work at the Hartley Institute, Southampton, and also taught at Winchester College and the Training College, and was appointed anal\st to the Borough of Southampton, and also to the main division of Hampshire. When Cooper's Hill College was established, the Indian students, who were the mainstay of the Hartley Institute, migrated thither, and Mr. Bickerton, becoming dissatisfied with the unsettled state of the Institute, received offers of man\- posts, among them being the Professorship of Chemistry at Christchurch (Canterburv College, University of New Zealand). This offering a more unrestricted and broader field, more leisure and opportunities for original research. Mr. Bickerton finally accepted, the authori- tion to astrononi)- and particularly to the stupendous nature of temporary stars. From this attention the thcor\- of partial impact and the formation of the third bodv, so lucidly explained by Professor Bicker- ton in his articles in " KxoWLEDGi-:,"' was evolved. .Mthough the formulation of the salient features of the theory, or rather induction, took but a short time, it was some years before the magnitude of the discoverv became apparent to its originator, and as its truth was tested in relation to other celestial phenomena than novae it gradually dawned upon him that he had discovered what has been justly called " the master-key to the Cosmos." His advocacy, however, of this theory outside the College, gave great offence to a certain section of the Board of Governors, and in 1894 and again in 1899 attempts were made to oust him from his position. The first failed lamentably, as at the enquiry it was proved that his students gained more scholarships than all the rest of the colon\- together and the kn()\\ij:i)c.i; jANtAKV, 191 lluiiunis simisscs in pliysical scii-ncc anion^; his stiuiuiUs wiTf more ihan scvni times as mimtroiis 1)11 an average as tliosi' of aiiv otlicr professor in New /ealanti. The second attack was mori- snccess- fnl. as lie was practicaliv f^iven tlu- option of resii^n- in}4 either liis theory or liis professorial chair. Pro- fessor Hirkerton valueil hispi>st less tlian his theory, so after some years his connexion with the L'niversit\' was se\eri' i-.mn- in l".nt;laiid to la\' his theory clearly Ixifore the scientific world, in the confident hope of securing its general acceptance. Professor Hickerton's object may be briefly stated as follows : — To explain his theory of Partial Impact and tin formation of the Third Hody and the many extra- ordinary properties it possesses, and to show that cosmic impact is not an accidental and destructive occurrence, liut a law of nature brought about by a great number of agencies, and that it is the most powerful constructive factor in the wlujle scheme of creation. We believe that all who have carefully read Professor Bickerton"s four articles will agree that he has made out a very strong case and that this theory deserves the closest and most sympathetic attention from all astronomers, professional and amateur. .A NAi'iRi-: ( .\i.i:\i).\ \\\ (.ii.i;i;kr wiini:. ii\ III r.i:KT II. I'ooLE. Gll.Hr.ur WillTi:, of Selborne, can need no introduction to readers of " Knu\vi,i;i)(;i:," for manv of us obtained our earliest natural history impressions from the fascinating pages of that old-time but perennially interesting volume " The Natural History of Selborne." Gilbert White kept very full records of his observations for over forty \ears, and his diaries (which have been preserved) begin in 1751 and continue until his death in 1793. For the first thirteen years they are mainly concerned with gardening operations and contain but few notes on will! nature. In 1765, however, a change occurs. White in that year bought a copy of Hudson's " Flora .\nglica." beginning in earnest the study of botany, and his notes reflect this new interest : but his ordinary diary for 1766 contains naught but garden observations, all his natural history notes during that Near being reserved for a special and uni<]ue compilation — the Nature Calendar w itli which we are now concerned. The Selborne Societv has just |)ublislied. in facsimile, a reproduction of this interesting work, which is edited by Mr. Wilfred Mark Webb, F.L.S. Ill the Introduction it is shown tliat this record was most proliablv cf)mpiled to form a basis for the ■■.\nnus Historico-naturalis " mentioned in White's last letter to Dailies Harrington. On the back of the title-jiage of the manuscrii)t it is called " Flora Selborniensis: with some co-incidences of the com- ing, and departure of birds of passage, and insects: and the appearing of Reptiles: for the Year 1766." It also contains a number of interesting weather records. I'roni this it will be seen that the work was not intemled to deal with jilaiits alone, but forms an exceedingly interesting genenil Nature Calendar. The total miiii!)er of species of plants that Wiiiti' recorded as occurring in tiie parish of Selborne is four iuindred and thirty-nine. In this Calendar for ]766o\er four hundred are detailed — a verv note- worthv list for one year. \'ery few records are secondhand, perhaps half-a-dozen ; all the rest are the personal observations of the famous naturalist. .An entry for July 2nd is of considerable ornitho- logical interest. It runs " Caught, and ascertain'd the Rcgiilus lion cristcittis. It is a very small bird, but bigger than the golden-crowned wren ; jiretty common and very mischievous among pease and cherries." It is well known that White differentiated the Chiff-chaff, W'illow-warbler and Wood-warbler wliich, until his day, had all been lumped together under the name of Willow Wren. This date probablv marks his first record of P/iyllascopiis and two years later, .August 17th, 1 76M, he enumerated the three species in a letter to Pennant. The wrongful accusation that the Willow - warbler is a frugivore. which he reiterated in Letter X\'I to Pennant, .\pril ISth, 1768, is a curious error for such a keen observer as Gilbert \\'hite to make. The three Pliylloscof}! are now considered to be entirely insecti\orous. Harting. however, has suggested that White may have mistaken the young of garden-warblers — which do at times eat fruit, and, as a species, were unknown to White — for willow warblers. In the ample Index much research has been devoted to the task of supplying the modern scientific names to the i)lants. birds, insects, and so on, recorded by Gilbert White: but a few still require identification. One example of these interesting lacunae is to be foiinil on page 5S which we are able to reproduce herewith. No. 27 2 of Kay's " Historia Insectorum " is doubtless Izristalis fciuix. but No. 27 1 is so far unidentified. (See Plate I.) "KNOWLEDGE," Volume XXXV (1912). Plate I, to face page 16. ^olMIa^ /r^/ik. aJ^te^^ /i/au^^ £t:HjA:f-tM£i ; ^/^^j^^a^ K^:e£Mi^^ A^/o AauH^ ^e^A. clajol./^ /^A/'/y~ Su sLA^LAt&/f graphs, with various aper- tures, have been obtained. Professor Wolf has published a complete series of the Milky Wdx, as visible at Heidelberg, made with angled lens, in " Die Milchstrasse,' and at the Harvard Station of Arcquipa. The piioto-telescopes of eight-inch and twenty-four- incli npiTtnr.-. tift.-.| vvit), ol.jrrtive iirisms. have small wide- and a great Fir.l'KK 33. Cy.sinus. mass of fresh material 'has accumulated from the photographic researches at Harvard College, Figure 32. Aquila. been diligently used, and the examinations of the plates by the late Mrs. Fleming have revealed the fact that certain classes of heavenly bodies are found almost without exception in or near the Milky Way. The stars of Tj-pe \', the Gaseous Nebulae, the Orion stars with bright lines, the Temporary stars, all tend to arrange themselves in positions of small Galactic lati- tude. On the other hand, as is well known, "white" nebulae and globular clusters avoid the Milk}- Way. The stars of Type \' show , above all others, not only an affinity for the Galaxy, but for the apparent centre of it. In 1891 our knowledge of the stars of Type V was extremely meagre ; there were the original Wolf- Rayet stars in a group in C)gnus; subsequently others were swept up with the spectroscope by Copeland and Pickering. An examination of the photographic plates taken at Harvard and Arequipa have re- vealed a large number of new ones, and it seems IS KNOW LI.DGi:. Jamarv, 1912. i|uili; ciilaiii tli.ii .ill tlu l>ri(,'litcT nu-mlx-rs liavu now Ih-i'M (liscovcnHl, tliouf^li fainter onrs from titiu- to tinu- an- (li-ti-cti-d. Now. if tlio stars of type \' are plotted ilown, it is found that they coincide in a riMuarkahle manner with the central circle of the Milky Way; s<» nuidi so, indeed, is this the case that tlu' circle is clearlv marked FlGCRE 34. Sagitla. nut In' them when they are sufficiently numerous, and even where the f^reat hifurcation takes ])lace, these objects persistentlx" follow the centre. The average deviation of the whole number is probably less than twn degrees. .As .Miss Clarke has ver\' truK said, we must belie\e that the Milk\ W'av is very much as we see it, and that it is not to be explained by two intersecting rings or by spirals. The \'-t\"pe stars may then be deemed to mark the absolute equator of the Uni- verse of stars. Now in the Southern Hemisphere, near the poles, and (]uite separated from all apparent connection with the Milkv \\'ay. are two cloud-like masses called the Nubecula Major and Minor. Herschel. after examining the Nubecula Major, was clearly of opinion that it was a iiiiilttiiii in parvo of the visible universe. Here, in the space of a few degrees, are found stars, irregular and globular clusters, nei)ulae planetary and irregular, all commingled in inex- tricable confusion. Photographs of the spectra of the objects therein contained, made with the twenty-four-inch Bruce telescope, have confirmed Herschel's dictum by re\ealing twentv stars of Type W fifteen objects showing the spectra of gaseous nebulae, and eight Orion stars with bright lines. — Comparisons of the |)lates have further revealed eight huni:i-L- ua.-, maJu v. ah a Cooke Lens ol" ahoiil one inch apciiiire al Areijiiipa and lasted tor i4 hours. liy the cuiirtcsr of l^ro/cssvr E. C. Piclicring, uf HurvitrU Co//c'i'c Observatory. Jamarv, 191 : KNOWLEDGE. 19 chart and the following elements obtained: — Semi- major Axis ... Pesition Anf^le Kccentricity Inclination ... 2° 35' .n. The pole of the Nubecula points almost exactly at <) Doradus, and there is apparently a condensation of nebulous objects at the poles. In the Nubecular Minor only one \'-type star has been found, but the general ap[)earance suggests a similar construction to the Nubecular Major, with a position angle of about 40". It is obvious that the mixing up of Galactic and non-Galactic objects must take place as observed by Herschel if the poles of these spheres are inclined to the line of sight. For instance, a \'-t\"pe star and a "white" nebula may be in the same field, the \'-type star being on the equator, while the white nebula is on the opposite side of the sphere, and consequently situated at a distance from the equator. Having examined this Uiii\irsc in miniature we mav now go on to apply its lessons to the Milky Wav. We take a sheet of paper and divide it into squares, and along the top write the hours of Right Ascension, and down the sides the Declinations. Next we lay down the path of the Milky W'ay according to Gould: then having made a collection of all the known Galactic objects, viz. — Type \' stars, gaseous nebulae, Orion stars with bright hues, temporary stars, we insert them in their proper places. Immediately it is obvious that the V type stars tend to collect in groups, the two largest groups are in proximitv to >; Argus and 1' Cygni, both of which stars have bright lines and have undergone remarkable fluctuations in light. >; Argus is associated with a remarkable nebula, and Professor Max ^^'olf finds vast nebulous patches in the C'ygnus region. Further, these places approximately coincide with each end of the great bifurcation of the Milky Way. A glance at our chart shows us also that the \'-type stars are much more plentiful in the region between Argo and Cygnus than elsewhere, and further that they tend to follow the medial line, and are grouped upon it at intervals. The gaseous planetary nebulae follow the same law, save that they are more widely distributed, and prefer the following rather tiian the preceding of the two Galactic streams. The distribution of the Orion stars with bright lines points to the same fact though in a less marked manner, while the temporan,- stars are more evenly distributed. Taking the per- centages of each of these groups we obtain the following table : — Type Plan. Orion Temporary Milkv Wav. V. Neb, Stars. Stars. Medial circle 78-S ... 5-4 ... 15-8 ... 25-0 Preceding stream ... 0 ... 26-8 ... 28-9 ... 40-0 Following stream ... 21-2 ... 67-8 ... 55-3 ... 35-0 If we examine the region from Argo to Cygnus we find in each case the tendency is rather to groups than to uniform distribution. Passing from the great Argo group at Galactic longitude of 255° a group of V-type stars occurs at longitude 275", a second at 320". At this spot the planetary nebulae, so far scarce, begin to collect on the following stream of the Gala.xy, coming to a maximum at longitude 340", and here in turn begin the more scattered temporary stars extending up to longitude 360'^. The planetary nebulae still continue plentiful up to longitude 30", then there is apparently a gap till the P Cygni region is reached. Beyond this the Galaxy is singularh- poor in bright line objects, and the stars of t\pe V, so far as they are at present detected, disappear altogether between longitude 110" and 190°. Before the latter degree is reached the Orion stars with bright lines begin to appear, and soon become numerous, lying persistently South of Milkv Way central line. One group seems con- nected remotely with the Orion nebula, and a second is found amongst the bright stars which mark the Southern limit of Canis Major. The following table shows in a striking manner the difference between the Argo-Cygnus region and the remaining 213 degrees of Galactic longitude : — Percent.^ges. Type Temporary Plan. Orion Des(rees. V. Stars. Neb. Stars. Argo-Cygniis ... 40-8 ... 81-7 ... 70-8 ... 66-7 ... 55-9 Rest of Galaxy ... 59-2 ... 18-3 ... 29-2 ... ii-i ... 44-1 Whatever inference we may draw from these results must be carefully guarded with the proviso that it is correct only as far c7.s our kiioicledf^e at present extends. Some thirty years ago the \"-type stars were confined to the Cygnus group ; to-day the vast majority are found to extend between >; Argus and P Cygni ; but at any rate we seem warranted in drawing the conclusion that in the case of the brighter members in each group of Galactic objects, the ratios of distribution are fairlv complete. With increased telescopic power the gaps ma\' be filled up ; but it will be with objects fainter than those at present known, and one or two alternations will present themselves, either the causes which produce \'-t\pe stars, and so on, are less active in one direction than another, or we are decidedly nearer one section of the Galaxy than we are to the other. At present the general consensus of opinion seems to be in favour of the latter alternative. Our illustrations show in the large plate the Milky Way from ten degrees to fifty degrees south of the Ecjuator. and the four smaller ones (taken b\- Professor Wolf with a small lens, and reproduced by his courtesy), carry us north as far as Perseus. Thus they cover the whole of the bifurcation, which, it will be seen, is much more obvious to the naked eye than on the pholographic plate. Throughout there will be noticed semicircular dark spaces, probably of absorption matter. IIAUMONOC.KAI'M TKAC I \( ;S Kl-C OUDIJ) HLECTROlA-rKAIJA'. By J. II. \ INCIINT. M.A.. D.Si .. A.R.C.Sc, AM. C. W. JlDi:. l'..S< . I.oiuliiii County Council Padilinfiton Tcclinicdl Institute. Anv form I iiarmono^rapli may he used in tlicsc expcrimrnls. The ordinary tubular writing pen is replaced 1)\- a steel needle with its jraint carefulh' blunted on a hone so as to have a smooth semi- circular end. This end forms one of the electrodes. The other electrode is a sheet of brass w hich is fixed firmly to the writing table of the instrument. The electrolyte is a solution of ammonium nitrate and (lotassium ferro-cyanide in water. The paper uj^on which the record is to be taken, is soaked in this solution and is then partially dried. The needle is insulated from the harmonograph by being thrust through a cork which fits tlie holder designed to receive the ordinary tubular pen : it is connected by a very thin wire to one terminal of the source of electric current, while the brass plate upon which the prepared paper is |>laced is similarly connected to the other terminal. If direct current is eniployeil an electromotive force of about twentv volts \\ ill be found suitable, though this will depend on the kind of paper used, and other circumstances. The provision of a rheostat for regulating the current will be found convenient. When the needle is safely started describing its path on the paper the current is turned on, and is switched off after any desired stage of progress of the record has been attained. Bv interrupting the current by a clock signal the period of vibration of either pendulum can be determined, or if these periods be known an irUerrupted trace will serve the purpose of a chronograph record. The direction in which the trace is niade by the st\le can also be recorded by this method. For exam|)le, a short interruption followed by a longer one would serve the purpose of an arrow-head on the trace and would indicate the relative direction of motion of the style and paper. If alternatiiig current is available, pictures like those in the accompanying plate may readily be jiroduced. In this case, the current being reversed man\' times a second, the electricity is flowing in the direction required to leave a trace, only for a small fraction of a second at a time. The trace then is built up of a series of more or less elongated dots, the intensity of each being greatest in the middle, and shading off to nothing at each end. The number of the dots marked per second is nearly constant, and is e(iual to the fre(]ucncy of the alternating supply. It follow s from this that the dots are siiaced on the trace so as to show b\' their remoteness or proximity to each other the cpiickness or slowness of the relative motion of the needle and paper. The velocity of the style with respect to the paper is given in centimetres a second b\- dividing the frequency of the suppl\- by the number of dots in a centimetre. It will be found that an effective voltage of about forty is suitable for use with paper of the thickness and quality of good unlined foolscap : but again it w ill be an advantage to have means of varving the voltage so as to obtain the best effects. .As with ordinary harmonograph curves, the more simple ratios of period give the best pictures. Figures i-v are all given by the ratio 2:1. the tuning being accurate in Figures iv and v. Figures vi-ix are given by the ratio 1:1, the only figure of these in which unison is exact being Figure vi. The initial phase is maintained throughout the diagram ill Figures i, iii, iv, v and vi, this being very accur- ately so in Figures iv, v and vi. In Figure ii, how- ever, the phase difference of the two pendulums is originally similar to that of Figure iv, and finally is like that of Figure i. Figure vi is the onlv diagram in which the dots are equally spaced throughout one complete oscillation of both pendulums. The velocity in each turn of the spiral is practically constant, but decreases as we approach the centre of the figure. In Figures vii, viii and ix we commence with an approximatelv circular path, but owing to unequal damping of the two motions, and to change (jf phase-difference due to inaccurate tuning, the final curve is a much flattened ellip.se of different orientation from the original one. In Figures i ami iii it will be seen that the trace was stopped when the left to right motion had almost died away, while the up and down motion was nearly as vigorous as at first. This effect, which ma\-, of course, be shown with any harmono- graph, whether the printing be electrolytic or other- wise, can be produced either bv using pendulums with bobs of very unequal weight, or by damping the motion of one by means of a flat flexible spring rubbing lightly against the rod of the pendulum so as to press on the rod in a direction at right angles to its motion. KNOWI.l nc.l".." Volitnic XX.W (I9IJ). Plate III. to face paiie 20. *A«^1?<<^==^ FiGL'KE iv. FlC.l'KK V, I'lGLKE viii. Harmon. >gr:ipli liacin.L;:^ which have boon recorded Electrolytici QUERIES AND ANSWERS. Readers are invited to send in Oiiestions and to ansicer tlie Queries tcliich are printed here. QUESTIONS. 1. ASTRONOMY.— In Sir K. Ball's "Elements of Astronomy," page 366. re astronomical constants, a number of quotations are given as to the co-efficients of aberration : tlio three largest values arc those of C. A. F. Peters. 1844. .'0"-50J: Newcomb, 1S95, 20"-5H: Maclear, 1850, 20"- 530. Have any recent calculations been made giving larger values ? In observations regarding aberration so much depends on the allowance made for refraction, even when stars near the zenith are selected, that it is not surprising that Sir K. Hall gives twelve different .. .. Sun's declination, li .. ., ., hour angle. / .. .. .. Zenith distance. Referring to Figure 36. and considering the spherical triangle Z V S we have. cos Z S = cos Z P cos P S + sin Z P sin P S cos li. or cos Z sin 0 sin S -\- cos if cos S cos h. (1 1 Now, as the horizontal refraction is 34' and as the Sun's semi-diameter is 16'. the Sun's upper edge appears on the horizon when his centre is really 16' + 34' = 50' below it. Making Z = 90° 50', we have, cos 90° 50' = -sin

sec. S, or cos

+ d = 89° 10', .-. 5 = 89° 10' - 86° 30' = 2° 40'. The Sun will not s<-t. therefore, if his Northern declination exceeds 2 4()'. In finding the time of continuous long dawn we shall assume that twilight begins when the Sun approaches within 18° of the horizon. The dawn will cease when his upper edge appears on the horizon, as daylight commences then. Referring again to our first eciuation, we see that Z S = 90° + 18° = 108° when dawn commences. Also if h = 180° or cos h = — 1, twilight will contiime all night, since — — = 24 hours. l3 Making these substitutions we find, cos 108° = sin <)> sin S — cos

72 — 0, twilight will continue all the night, even at the time of greatest depression, i.e., 18° below the horizon: hence, 5 > 72' — 86.V' > 14J° S. We have seen that the Sun will just commence to rise when his Southern declination is less than 4° 20'. The twilight, or continuous dawn will, then, endure while the Sun changes from 14i°S to4° 20' S. KNOWI.KDGi:. Jamtaky. 1912. TIh' following is :i siiininary of oiir it'siiils: From 14° JO' S to 4 20* S. coiiliiiiioiis dawn. l"iom 4° 20' S to 2 40' N. altoiiiatioiis of twilij;lu ;iikI SMnlight. l"ri>Mi 2" 40' N until llip Sun cnniplctcs his most Northcrii course and returns again to 2 40' N, llic-ro will be no sunset, but one long d.'iy. Wf shall now refer In the Niuitic.il .Ahnanac for this year. On I'ehruary lOlh. about ') p.m.. the Siui attains a declination FlGlKK .56. 14° JO' S. Tlic continuous dawn has then commenced. On M.uch llth. at noon, his dechnation is 4° 2' 24" S., so that twilight has commenced some tiiTie previous to this. The interval is about 2SA days. If. however, we take 17" as the aiiijlf below the horizon when twilight starts, we should recliou from IJ' 30' S. This would reduce the time of continuous dawn to 25i days. It is easily seen from this how impossible it is to give the time of continuous dawn exactly, because the angle below the horizon varies with circumstances, such as atmospheric conditions, and so on. It is not exactly 18° under all circumstances. Or. March 28th, at noon, the Sun is just short of 2° 40' \. by 30" • 7. Practically, then, we may say that the long day has commenced on March 2Kth. Reckoning from March llth to March 2Sth. we obtain about 17 days as the time of alternation of sunshine and dawn. On September 17th, about 8 a.m., the Sun has again attained a declination of 2" 40' N. The time from March 2Sth to September 17th is 173 days. But we umst deduct slightly from this, because we have assumed daylight to start the instant the upper edge of the Sun appears above the horizon. We must allow a little time after this before the long day actually commences. l-'or the reasons just given, we can only obtain an approxi- mation to the number of days in each period. The figures may vary slightly according to local conditions. If we adhere strictly to the above reasoning, a latitude 86^ 8' \. gives 171 days for the long day. Probably 8f).J° N. most nearly fulfills all the conditions, because a less latitude than 86}° N, increases the time of alternation of sunshine and twilight. It may be interesting to notice that in Lieutenant Shackle- ton's book, "The Heart of the .Antarctic," it is mentioned how the Sun was seen for the last time in I'JOS, on .April 27th, when one-third of the disc was above the horizon at noon. He was seen again first on August 17th, when his entire disc was above the horizon, and the lower edge one- fourth his diameter from it. He could, it is stated, have been seen a day or two earlier if the day had been clearer. The Latitude was 77 30' S. This fact shows how difiicult it is to predict the above times accurately to a day, as fogs and ini.sts will always modify the results. The Sun cannot appe.ir in the manner suggested. Con- sidering that his declination is increasing by about 23' 30" at that time, and that his apparent diameter is i2'. he could not take more than two days to rise above the horizon. If. in ecpiation (II. we substitute 4' 2' 24" for «, the declination on March llth, and 90° 50' for 7., and solve for h. we find h 23 42', .'. „ =1-58 hours. The total length of the day is greater than twice this, since the increasing declination makes I he afternoons longer than the mornings. His upper edge is above the horizon for a longer time than 3 hours 9 minutes on this d.iy. l-'or the next day we find the time to be 4 hours 50 minutes- and for the next 6 hours 8 minutes. The whole number may be easily worked out from the formula. In these examples we assume 5 to be that of noon, and neglect its small change in the time. Of course these times vary from year to year, as the Sun will not attain to precisely the same declination on the same day each year. The first day would be 1' hours long, if the Sun's declination were somewhat less than 4° 2' 24". If we reckon the time from which the Sun actually attains 4 20' S., that is, on March 10th at 6 p.m.. to the time when he enters the Vernal Equinox, that is, 6 p.m. on March 21st, the interval is 1 1 days. From a few calculations we find the change of longitude in the time to be 10 55'. If this time on March 10th correspond with the instant the Sun is in the constellation mentioned. 120°. then at X'ernal Fquinox we shall have 129°+10 55' = 139°55'. diflering by 3' from the longitude given. This difference corresponds with a time of about 1 hour 12 minutes, so that the calculation by " Baroda" is practically correct for this period. If some liglit were thrown on the precise time these phenomena occurred, it would simplify the c.ilculations asked for with reference to New Moon, and so on. (Rev.) M. Davidson. 51. (".KOL(X;V OF SOUTH DORSET (ISLE OF FL'RBECK). — The geology of this district offers wide scope for practical field geology on account of the number of strata which are so well exposed in coast sections. A detailed account as suggested by S.P.R. would necessitate quite a lengtliy article to deal at all adequately witli the geology from the point of view of strata alone, without mentioning fossils and minerals. The chief places of interest in the locaHty are as follows : — (1) Durlston Bay, where a splendid section of the Purbeck beds is exposed, and in fact duplicated in part by a fault. (2) Swanage Bay. with Upper Purbeck at Peveril Point. Wealden. Lower ("ireensaud. I'pper Greensand and Clialk at the more northerly end of the bay. (3) Studland Ba>'. with I'ppcr Chalk and Bagshot sands. (4) St. Alban's Head and Chapman's Pool, with Portlaudian. Purbeck and Kinnneridge Clay. (5) Kimmoridge B.iy. where many faults almost diagranunatic in their distinctness may be seen. (61 Lulworth Cove and Stairhole. showing steps in Cove formation and strata compressed and contorted. (7) Durdle Cove, showing further stages of coast erosion and cove formation. (8) Bournemouth, with Bagshot and Bracklesham Beds containing noted leaf beds. I would suggest that S.P.R. should purchase "The Guide to the Geological Model of the Isle of Piubeck," by .Aubrey Strahan, M.A.. F.R.S. ; Price Od. Publishers: E.Stanford, 12. 13 and 14. Long .-Vcre, London, which gives an interesting and useful account of the district required. Hekuekt 1-. Tavlok. TTIK FACE OV TIIl^: SKY FOK 1-FRRl'AHV I'.v A. (■K()Mmi;lin. I'.. a., d.s,,, i.k.a.s. Dale. Sun. Ma K>n. Mercury. Venus. Mars, Jupiter. S.iturn. Nepiune. R.A. Dec. R..*. Dec R.A. Dec. R.A. Dec. R.A. Dec. R.A. Dec. R.A. Dec. R.A. Dec. c ;rcenwich Noon. I9I2. h. ni. h. in. ^ h. m. h. m. h. m. h. m. 0 h. nl. „ h. in. 0 IV-b. 4 .. 21 7-2 S.16-5 'o 34'S N.ij-i ■9 533 S.22-1 18 290 S.22-1 3 55-7 N.«-7 .6 37-0 S.2I-3 2 47-6 N"3-8 7 33'9 N-21-1 ' -■7-3 S.15-0 14 41 2 S.17-4 20 23-0 S.20-9 18 551 S.21-9 4 3-5 N.230 16 40'i S.2r'4 2 48-4 N-n-9 7 33-4 N.21-1 ■ I : 47-0 5.13-4 19 0-4 S.27-7 2n 580 S.19V 19 21-3 S.21-S 4 11-8 N.23-4 16 430 S.21-5 2 49-3 N.140 7 32-9 N.21-2 • 6-5 S.ii-7 23 5'u S. 94 21 32-2 S.IO-S 19 47-2 S.20-8 4 20-7 N-.23-7 16 4?-7 S.2r6 2504 N'.i4-. 7 32-4 N.21-2 -'1 - 25-6 S. 9-9 I 59'5 N.19-3 22 6-1 S.13-9 20 13-0 S.19-8 4 30-. N..4'. in 4S 1 S.21-6 2 31-7 N14-2 7 32-0 N.21-2 .. 20 .- 22 44-5 S. 80 8 90 N.254 22 40-5 .S.io-4 20 38-4 S.iSo 4 W. N , -•■■7 2 53-1 N.14-3 7 31-6 N.21-2 Tabi.i-; 1. 1 i.ite. Sun. Moon. Mars. Jupiter. Saturn. P B I. P . '' „ li L Q q T P 1) '•. L„ T| T„ P B ^ h m „ h in ll n. 0 0 I'-i'. t - 13*2 69-2 + 20-6 324'4 - 12-0 91-9 78-8 ■92 5 42 '" 7 9 -2-9 35i'i 151-6 2 23 M 7 48 «/ - 0-6 - 20-7 0 15-1 6-6 3 '4 + 16-1 324 '8 11-2 446 79'3 8 57 m 7 '6 2-9 60-3 182-6 8 11 «• 4 53' 0 6 20-8 ., 14 16-9 297-6 3253 10-4 357 ■■ 79'9 ■87 0 12 tf 7"3 2-9 129-5 213-7 8 27 m 4 !<• 00 20-9 .. 19 7'o 231-7 -21-5 325-8 9"5 309-6 80-6 •84 3 27<- 7'i 2-9 198-7 244-8 4 24« 5 14 "' 0-7 21-0 .. 24 20-| 7'i 165-9 -14-8 3=*'5 S-6 262-0 8.-4 -82 643^ 6-8 2-9 276-0 4 39'" 0-7 2I-I -. 29 -21-5 -7'2 + 12-1 :.27-2 - ■ 7-6 2.4-2 82-2 ■79 9 59 f 6-6 -2-9 337 '5 307 '3 10 27 t- 3 31 '" -0-7 -21-2 Tabi.1-; 2. P denotes the position angle of the axis of tlie body measured castwaid, from the North Point of the disc. R is the Hchographical (Planctographical) latitude of the centre of the disc. L denotes the longitude of the centre of the disc, T the time of transit of the zero meridian across the centre of the disc. In the case of Jupiter there arc two systems of longitude, I, tor the ctjuator, II. for the temperate zones. To find intcrnic- diate values of T apply nniltiples of 24" i9"'.9^ SOi". 9" .S-ir,'" for Mars, Jupiter I and II, respectively. Throughout these not(>s the time used is Greenwich Civil Time, day commencing at midnight, and the letters /;;, c. stand for morning and evening. O, q. for Mars are the position angle and amount of the greatest defect of illmnination. The Six moves North fairly rapidlv during February. His semi-diameter diminishes from 16' 15" to 16' 10". Sunrise and sunset at (Greenwich, Feb. 1.7''4.i"' ;;/, 4'' 45'" c ; Feb. 29, 6" 50™ in, 5" .?6"' e. The Moon is I-'ull. l-~eb. 2'' ll'' 58"' c : Last (J., Feb. 10'' o" 51"" III ; New, Feb. l.S'' 3'' 44"" ;» ; First O., Feb. 25'' 7" 27"' c ; Nearest Earth, Feb. 2** 2'' in, semi-diameter 16' 42"- 8 ; Furthest away, Feb. H** ll'' n;, semi-diameter 14' 44"-,^; Nearest March. 1'' t)" in. semi-diameter, 16'30"-4. Greatest Libration 7° S. Feb. 1 ; 7° VV. Feb. 7 ; 7° N. Feb. 15 ; 6° E. F"eb. 23 ; 7° S. Feb. 28. The letters N. E. S. W. indicate the region of the Moon's limb (referred to our slruary 2nd Ceres has the same Declination as Castor, following it by 21 minutes. To 6ntl the pl.-inet point a telescope at Castor and leave it stationary for 22 minutes. January, 1912. KNOWLEDGE. Star. Right Ascension. Declination. Magnitudes. Angle. 1 Distance. Colours. Siruve 1024 h. n.. 7 4 38" iS'N 8-3. 8-8 316° i" \-ellow, while. ■037 7 7 27 23 N 7'. 71 295 i White. 1051 7 'o 73 ijN' 6-5, 8-6 1 282 I 1 6> 6 7 1 82 31 1 Triple, while. ., >>'55 7 15 60 5X 6"0,'0'5 .>24 2 White. \(jcmini.»ruin 7 13 16 42 N 3-2.1 03 33 9 Bluish-green. 19 Lyncis ... 7 >6 55 27 N 5-3. 6-6 315 IS Hluish-while. JO Lyncis ... 7 16 50 19 N 6-6. 6-8 254 15 White. iGeniinoruni 7 15 22 9N 3-2, 8-2 209 7 Yellow, blue. S:ruve 10S3 7 20 20 40 N 6 8, 7-8 43 6 Yellow, blue. 1097 7 24 II 23S 63, 8-2 1 169 I 1 6-3. 87 313 1 157 20 Quadruple. 6-3. 10-6 23 ' ,, 1104 7 2j 14 49 S 67. S-3 332 2 White. 1 .istiir 7 29 32 SN 2-7, 37 222 55 Yellowish-i;reen. .■-iruvc ni6 7 29 12 29 X 7-0, 77 106 2 White. 1121 7 33 14 18 s 7-2, 7-5 304 7 White. ,, 1122 7 3S 65 22 N 6-8, 76 5 15 White. 1126 7 35 5 26 N 7-2, 7-5 MS 1 White. 11' East of I'rocyon. ,, ii?7 7 39 64 17 N 6-2, 85 6-2, 9'o 338° 175 5 / II 1 Triple. 113S 7 40 14 28 S 6-2, 7-0 339 17 White. 114" 7 44 II 59 S 5-3. 7-4 13 3 Yellow, blue. ; "77 S 0 27 49 N 65. 7-4 352 3 Bluish-white. ., .II7S S 4 32 29 X 71, S-o 46 2 Yellow. jCancri .. S 7 "7 55 N 50. 57 5-0. 55 2 114 1 1 5 < Triple. Struve 1216 S 17 I 19S 7-5. S-2 215 i White. ^ancri S 21 27 14 N 6-0, 6'5 217 5 Yellowi.sh. i/'Cancri S 21 24 50 N 60, 7-1 41 6 White. Struve 1245 s 31 6 56 X 60, 70 25 10 White. „ 1263 8 39 42 iN 7-6, S-2 22 60 White. An optical double. 76 has larye proper motion. iCancri ... S 41 29' 6'N 4 '4, 65 307" 30 Yellow, blue. tUydrae 8 42 6 45 N 38, 7-8 222 1 1 3-8. S-S 231 4 Quadruple. 3-8, 120 195 20 1 (i^Cancri 8 49 30 56 N 5'9. 64 326 li Yellow. 66Cancri S 56 32 36 N 6-1, 8-2 138 4 White, blue. Figure 4. Double Stars between Right Ascension 7" and 9". Mercury is badly placed for Northern observers, but may be seen as a morning star at the beginning of the month. It presents a nearly full disc, being in superior conjunction on March 1st. It is on the same parallel as \'enus on February 4th, and may be found by pointing a telescope at Venus, and leaving it stationary for l"" 24"". Venus is also rather badly placed, being South of the Sun ; * of the disc is illuminated, the diameter diminishing from 14 V' to 12 J". Mars is still a bright evening star in Taurus, but is rapidly receding from us. The diameter diminishes from 10" to 7". The seasons on the planet correspond to the first half of April on Earth. Both poles are invisible, since the Sun and Earth are on opposite sides of the planet's e 13 ,1 21 41 0 32 . 7 4'3 ( "^ 2 ., 22 43 12 , 8 43 ( J) 12 .■ 23 432 l.i • . 9 '2 ( J) I ., 24 432 0 . 10 Si C J 2« .. 25 4 0 ■|2 > II c J 4132 ,, 26 41 0 3 . 12 12 ( J 43 .. 27 24 0 I^ . l> 2 ( 1 134 „ 28 I (J 2j , 14 I ( J 324 „ 29 3 0 124 . IS 3 C _) 124 Table 5. Phenomena visible at Greenwich: — I. Sh. E. 1'' 4'' 12"" II. Sh. I. 5" 16'", I. Tr. E. 5" IS"'; II. Oc. K. i"" 4" 30"" I I I. Ec. D. 7" 30"" 22" ; II I. Tr. E. 7" i" 43'°, I. Ec. D. 6" 43'" 52' I. Sh. I. «•' 3" 52"". I. Tr. I. 5" 1"". I. Sh. E. 6" 5"", I. Tr. E. 7" 14" I. Oc. R. 9''4''32"'; II. Oc. R. lo" 7" 10"'; III. Tr. 1. 14" 5" 56"" I. Sh. I. 15" 5" 45'". I. Tr. I. 6" 57"; I. Ec. D. 16" 3" 5" 51" I. Oc. R. 6*' 29" ; 1. Tr. E. 17" 3" 39"", II. Ec. D. 4" 49'" 54" II. Tr. E. 19"4'' 52"; Ill.Sh. I. 21" 5" 5'°, III. Sh. E. 6'' 59" KNOWI.I.Df.l Jam'akv. t'»|j. I. Kc. D. 2i" 4" 59"' 19*; I. Tr. 1. 24"' 3" 21"", I Sh. K. 4" l'*'". I. Tr. K. 5" 34"': I. Oc. K. 2.V' 2" 53"; II. Tr. I. 2(.'* 4" 52'", II. Sh. K. 4'' S'*"". The abovt* arc all in the inorniiiK hours ; pheiioiiifiia separated by coiiiinas arc all on the same day. Kclipsesucciir hit;h left of the disc in the inverted iinage, lakiiiK the direcliiin of the belts as hori/nnlal. IV. does not imdcrRo eclipse at present. Sa riKN is approachiliK the Sun. but still easily observable. I"<|iiatorial diameter IS". Major axis of riii); 41". minor 15". The folliiwitiK Table nives ICast elonj;.ili()iis of Satellites. To liiid intcriiu'diate ones appiv multiples of l** 2l'' for Tethys. 2" l,s" for I>ione, 4" 12. J" forKhea. Tethvs Keb. 1" ll" c ; 7'' 3" c : U" 7" m ; US'" 1 1" f : 24'' 3'' c : 28'' 9'' III. Dioiie leb. l-" 5'' c ; 7'' 5'' ;;/ : 12'' 4'' c : 18'" 4'' in: 2i'' 3" c : 29'' 3" m. Khea l-eb. 1'' ;/oo/i : lOJ ]i. ^.. ig.i 2" c; 28'' 3"f. For Titan and lapctns E., W., denote East and West KlonKations, I.S. Inferior and Superior Conjunctions. Titan Keb. 2'' S" in 1. fi"" 4'' in W, 10'' 2'' in S. 14'' (•,'' in E, 18'' 7'' in I, 22'' 4'' in W. 26'' 2" in S; March 1'' r.'' in ]■:. lapetus Feb. 5'' 8'' ;/( W, 24'' n'' c S. L' KAN IS remains invisible. Niit'Tl'Nli is very well placed in (lemini. The map given last month is still available for lindinfi it. CoMLTS. — Fphemerides for three comets in February were t;iven last month. Prolonged observation of (Jnenisset's coitict is desirable, as it may possibly be identical with 1790, III. MliTliORS. — Mr. W. F. Denning gives the following showers. l>;ile. Kadiani. K.A- 1. N.,1.-. 111., s-io.. 75 4" N 236 II N 2.,i 4 X Sluw, briylit. Swift, streaks. Swift, stieaks. Swift, ljii[;lit. Swift, streaks. Minima I'' 10'' ni. )!• Al.Gol..— Feb. l-* 3'' c. 10' 5" in. IS-" 7" c, Period 2* 20'' 49'". Every 3rd mitiiiiiiiiii given. Clusters and Nebulae. Name 1 K.A. Dec. Notes. W J\"- 45 1 7" 23'" 21" 7'N. Nebula. W VI 1 1 7 j! 21 4S N. Cluster. y VIII 3« 7 3- ■ 4 ■ 3S. Loose cluster. ^ VI. ?7 7 35 10 28 S. Cluster. M. 46 7 37 '4 3+S. Cluster. « VI. 64 , 7 3S 17 56 S. Planetary nebula. M 93 7 40 23 35 S. Cluster. W VII- 1 1 8 6 12 36 S. Loose cluster. "S VI. 22 S 9 5 2SS. Cluster. M. 44 S 34 20 2C N. Praesepe cluster. M. '' s V. 1 2 ■ 3N- Cluster. .M.A1"11HM.\T1C.S AM) I'lIV.SIC.S IX Till: i:XCVL Lol'AKlJl.V llRriWXXKA. Tm; eleventh edition of the " Encyclopaedia Hritannica " is of a vintage, which, judging from the initials of the contributors of its articles on mathematical and physical subjects, needs a bush no more than the ninth edition. Hush or no bush, such a production cannot pass unnoticed, though to discuss adequately even one group of articles is beyond the powers of this reviewer, even if the attempt were not beyond the scope of this journal. Mathematics and physics have always been special features of this work, and in the present edition the compilers have kept this fact in mind. There is not in English, as there is in I'rench and German, a Dictionary or ICncyclopacdi.i of Mathematics, and the eleventh edition of the "' Encyclopaedia Britaimica " aims definitely at supplying this need. This means that a large number of new articles have been written, while a few of the older articles re-appear. Among these, of course, we find treatises by such men as Cayley and Tait, which have become in a measure classical. On the other hand we have our attention called to the modern trend of mathematical thought by the new article " Mathematics." This, contributed by A. N. Whitehead, takes the pUice of ProfessorChrystal'sarticle. The sameauthonwith Mr. Bertrand Russell, contributes sections under the heading " Geometry," an article which combinesold and new. ProfessorO. Heiirici dis- cusses Euclidean. Prospective, and Descriptive Geometry, while Cayley"s Analytical Geometry has been revised by Professor E. H. Elliott. .-Vmoiig other contributors in Pure Geometry we notice the names of 1-2. W. Hobson, A. E. H. Love and H. F. Baker. In Applied Mathematics Professor H. Lamb. Sir George (ireenhill, and Sir George Darwin, are noteworthy contributors. Physical Science moves so fast now-a-days that a treatise may become out of date in the course of its preparation for the press. We refer, of course, more particu- larly to the rapid growth of the new study of radio-activity. But the new views on the structme of matter are bound to have their cfTect in all branches of Physics. In the eleventh edition the group of .irlicles of which the Properties of Matter and the .Aether form the theme are particularly noteworthy. Part of Clerk Maxwell's famous article " .Atom " can never be out of date, and reappear imder the heading "" Molecule." The present occupant of Maxwell's chair. Sir J. J. Thomson, contributes a new article " Matter." Sir Joseph Larmor's " .Aether " contains all that was valuable in .Maxwell's " Ether " modified in accordance with the prevident views. More of Maxwell's distinctive work reappears in Lord Kayleigh's "Capillary .Action" and Professor G. H. Bryan's " Diffusion." Lord Kelvin, the last survivor of the great " Early Victorian " group of Cambridge Physicists, contri- buted two famous articles to the ninth edition : "Elasticity" and " Heat." He survived long enough to be consulted with regard to these, and there can be no question that in handing over to Professors .A. E. H. Love and H. L. Callendar the task of bringing them up to date, he made an admirable choice. In the region of "' Light" Lord Kayleigh is fortunately still with us. and his new articles on " Diftraction" and "Inter- ference." both of them experimental as well as mathematical, take the place of his former "Wave Theory" and Professor Tail's '■ Light." The remarkable advance in optical instru- ments due to the work of Abbe and Schott finds recognition ; and articles on "Lens" and ".Aberration" have been con- tributed by members of Zeiss' staff at Jena. In Electricity and Magnetism a noteworthy transformation has been made. Professor G. Chrystal. of Edinburgh, taken by death from his work since these p.ages came into the reviewer's hands, was the author of the articles in the ninth edition, which were regarded as the best existing text-book of the " eighties." In their place we now find a series of articles by Professor J. A. Fleming, Sir J. J. Thomson and others, which are as far as possible up-to-date, and which by their headings and arrangement simplify the process of reference. As an example of the difficulty of keeping abreast of the times in such a work as this the reviewer may mention that he has been unable to find either under the heading " Compass " or " Gyrostat " any reference to the Gyrostatic Compass. Ki{\ir:\\s. AERONAUTICS. Niitiinil Shihiltty ill Aeroplanes. — By W. Lie MAliKii. 4() pa^os. .53 illustrations. 7i-iii. X4'f-in. (E. & F. N. Spon. Price 1/6.) This book is the expression of the personal opinion of the author on the subject forming the title. There is also a rough description of a machine designed in accordance with prin- ciples which he has deduced from experiments madr with small gliders. His main deduction is tliat machines with short wing span and low centre of gravity will make the best and most "etficient " machines. The author seems to be under the impression that liis principles have never been tried; he is very much mistaken on lliis point. As to the deductions themselves, short span and very low I L litre of gravity are almost diametrically opposed to the generally accepted necessary conditions for proper efficiency, and the propriety of these conditions, besides being demon- strable by laboratory experiment, is fully confirmed by the results in practice. It is also a fairly well-known fact that by increasing or adding to the resistances of an aeroplane, one can increase its stability, but at the expense of its efficiency or the power necessary for flight. The only proper deduction from the author's experiments is tliat a machine constructed to the author's designs, when once up, could, on a very calm day. form a steady glide to earth, (somewhat steep, very possibly), but that such an inefficient machine ever would "get up" is, to say the least, problematical. .,- ... ,- ,. Liinglcy Memoir o/ Mecliaiiieul Fti^lit. (Published by the Smithsonian Institution, W'a.shingtoni, In this book we have the long looked for full description of .ill the wonderful and patient experimental work of the late Mr. Langley. The work, which has taken eight years to complete, is a monument to the single-minded thoroughness of the experimenter, and to the untiring energy of his most able assistant, Mr. Manley, and the result far exceeds the most sanguine expectations. The size of the work precludes any adequate description of its contents ; suffice it therefore to remark that it consists of over three hundred p.iges of text, written in a clear, concise and interesting manner, and well printed on good paper. There are in addition one hundred and one full page plates, all clearly reproduced from photographs. These shew various rubber driven models (there are thirty-one of these), power models (four of thescl. the same in flight, launching apparatus, man- carrying machines, surfaces, automatic equilibrium devices, boilers, and numerous others, most of them having their details shewn separately. Here may be read the troubles attendant on making light motors, and how, (in 1900). when searching over Europe for a light petrol motor, all the builders were agreed that a light twelve horse-power motor could not be built to weigh less than two hundred and twenty to three hundred and thirty poimds, and how^ finally Mr. Manley personally assumed the responsi- bility of making the same, and successfully produced one of twentv-four horsepower weighing one hundred and twenty pounds only, a result comparable with present engines. To those who interest themseh>es in " Flight " this book is essential. .,.^ ^^._ ^_ ^^_ ciii:mistrv. The Relative \'i)li(iiies of the Atuiiis of Cartmii, Hydrogen and Oxygen, u-lien in Combination. — By H.wvkswortu Collins, B.A. (Cantab.). 107 pages. 8i-in.X5A-in. (Morton iS: Hurt. Price 7 6 net.) To Hermann Kopp is due the honour of having made the first systematic attempt to discover the relation between the chemical constitution and the physical properties of bodies. .\mongst these properties he gave perhaps greatest attention to that of molecular volume. He concluded that molecular volume is an additive property, i.e.. that the volume of an atom in combination is a fixed quantity (within certain limits) at any temperature, and that the volume of any molecule is the sum of the volumes of its constituent atoms. He assigned the following values to the atoms of Carbon, Hydrogen and Oxygen— C = ll;H=5-5;0 = 12-2 or 7-S according to whether it is carbonyl-oxygenor hydroxyloxygen. Researches carried out since the time of Kopp have shown that the matter is not so simple as this : the arrangement of the atoms has a decided influence upon the molecular volume, (as Kopp recognised in the case of oxygen), isomeric bodies by no means always having the same molecular volumes. The author of the present work has given many years of study to the solution of this problem, seeking for some consistent method of interpreting the values for the molecular volumes of various compounds obtained by experimental chemists. And as a result of this study, he has devised a method of calculating the molecular volumes of various bodies with a (luite remarkable degree of accuracy. In the present work he deals only with compounds containing carbon, hydrcjgen and oxygen. He finds that the molecular volumes of such bodies at 15 C may be calculated by giving the following values to these atoms — C= -71, or in some cases 8-0; H = 15-25, 12-22. 9-. GEOGR.APHV. \'e\c Zealand. — HyTHE Hon. Sik Roui;rt SriK i . K.C.M.( ... LL.D., and J. Logan Sturt, LL.B. The Cambridge Manuals of Science and Literature. 185 pages. 20 illustrations. 6.5-in.X4Mn. (Cambridge University Press. Price 1 - iiet.i This little book forms one of the Cambridge Science and Literature Series ; in our opinion its contents are neither the one nor the other, and we do not (juite see for whom the book has been written. True, a great deal of information is stored in its hundred and eighty-five pages, .ind the names of its distinguished authors are a sufficient guarantee of accuracy, but further than this we cannot commend the book. We should certainly hesitate to place it in the' hands of a schoolboy. .As a book of reference, or as a guide to New Zealand, it does not seem to be sufficiently detailed, while as an introduction to the study of the country, its produce and people, it fails to stimulate curiosity or interest. Modern geography teaching consists not merely of the stringing together of facts, to be committed to memory by the pupil, but it tries to answer the question " Why." and after presenting certain principles, shows as far .as possible how these may be brought to expl.iin not only the (ihysical but the political geography of a country .as well. We look in vain for any such guiding plan in the xolume under review. We hold tlial a crowd of facts with little or no explanation is useless Janlarv. I'Ui. KNOWLEDGE. 29 from an educational point of view, and that tlie facts them- selves, even if retained in the memory, are not likely to be of much value to the general reader. The book, however, would probably be of service for the answering of examination questions of a certain type. The illustrations taken from photographs are fairly successful, the one of Lake .Ad.i being perhaps the best ; but surely a good map would have been a more useful frontispiece than a specimen of Maori carvini; ! \I n H Textbook of Gcotimphy.—By (',. C. Fry, M.Sc. 2nd 1-klition. 4(icS pages. 96 I'igmes. 5-in.X7-in. (University Tutorial Press. I'rice 4 O.l In the second edition of this useful textbook a large number of maps and diagrams have been added. The statistical information is brought up-to"-date, and an appendix containing numerous examination questions is supplied. These certainly .idd to the utility of this compact and comprehensive textbook. Whilst the illustrations are in general good and clear some of the coloured maps are not very successful, notably Figure 76. The book is intended for matriculation students, and is extremely well written and arranged. - ,,. ^- GEOLOGV. The Changeful Earth.— By G. A. J. Coi.i.. \1.R.I..\., F^.G.S. 223 pages. 51 F"igures. 4j-in. X7in. (Macmillan & Co. Price 1/6 net.) This fascinating little book is one of a series of " Readable Books in Natural Knowledge," which is intended to stimulate interest in scientific studies, and '" to present natural phenomena and laws broadly and attractively." That the book under review- fulfils this object goes almost without saying. Prof. Cole has written in his most attractive style the romantic story of geology as it is recorded in the lives and labours of its great pioneers. The history of the changeful earth is told in a series of chapters which describe the achievements of the pioneers in each branch of the science. The reader is gently led up to the present position of geology by a consideration of the development of the fundamental conceptions of the science in the minds of its earlier exponents. In the capable hands of the author this method of presentation is most successful, and we have read few books which are so likely as this to produce a lasting and fruitful enthusiasm for geology. The book is written in a simple and charming style, and makes its appeal as literature quite as nuich as by its interesting subject matter. As an introduction to geology for nature-students it will be found invaluable. ^ ,,, ^ ORNITHOLOGY. Tlw Home-life of the Osprey. — Photographed and described. Hv Ci.iNroN G. .Abbott, H.A. 54 pages. J2 pl.Ues. lOi-in. X7J-hi. (Witherby & Co. Price 6 - net.) The observations and photographs contained in this wuik were made in the Eastern States of .America, and Mr. Abbott, knowing that the Osprey is all but extinct in Britain, and that any nests existing in recent years were in solitary and remote places in the Scottish Highlands, remarks on the surprise with which he saw his first American Osprey "s nest. "It was," he writes, ■■ at a popular seaside resort in New Jersey, and perched on a tree over a lake full of row-boats and noisy holiday-makers" (page 7). The bird probably still nests, or attempts to do so, within the bounds of the city of New York. and on Gardiner's Island about three miles from Long Island (where the species has been protected for many years), it is estimated that some two hundred nests are in existence. Mr. .Abbott has put his opportunities on this island and elsewhere to excellent use, and has given us a series of valuable personal observations on the fishing, breeding and other habits of the Osprey. and on the rearing and conduct of young birds in the nest. He gives an instructive narrative of a continuous twenty-fi\e hours watch with his camera close to a nest with young, the object being to ascertain some definite data as to how often young Osprey s are fed. During this watch food was only brought to the nest three times, and Mr. .Abbott thinks that the young are not fed more than twice, or at the most, three times a day ; this infrequency surprises him, and he asks for further information. The numerous photographs by Mr. .Abbott and Mr. H. H. Cleaves accompanying the work are very fine indeed, and it is not too much to say that by themselves they tell the story of the bird. Some particulars are given of the photographic methods adopted in securing these pictures and the enthusi- astic pleasure which Mr. .Abbott expresses in this work is well justified. |_, i^ \y Report on the I iiiiiii}>rntioits of Sidniiier k'esulenls in the Spring of I'IKI. .Also Notes on the .Migratory Move- ments during the Autumn of 1909. — By the CoMMlTTKE ApI'OINTKD by THli BRITISH ORNITHOLOGISTS' ClUB. 314 pages. 21 maps. SJ-in.X 5:i-in. (Witherby & Co. Price 6/- net.) This is the sixth annual consecutive Report of the valuable and important work being done by the Migration Committee of the B.O.C., and they explain that the lines followed are similar to those of previous Reports. A great amount of information is given, but no remarkable phenomena or abnormal movements seem to have occurred during the period reported on. and the records are almost entirely similar to those of previous Reports and, of their kind, well known to observers and students. The accumulation of facts on a uniform system over a series of years is of essential importance in such researches, but it may reach a point at which it ceases to be information. For instance, it seems superfluous, and in no way an addition to our knowledge, to give in detail the ordinary dates of the arrivals of common summer bird-visitants, and these might be taken for granted, and only departures from the normal chronicled. Both the Editor and the Committee remark on the voluminous character of the Report and their endeavours to condense it. The attainment of this end would be assisted by their publishing only observations and returns of material importance throwing fresh light on the subject or containing new records. The space thus made available might be utilized in extending the field of the enquiry and amplifying its usefulness. A real advance might be attempted in co-opting and co-ordinating observations made by others, a task which the influence and learning of the B.O.C. make more likely of attainment by them than otherwise. The limited character of the Report as now compiled is shown in one direction by the records given of a few of the scheduled birds from the Clyde district (thus extending the work beyond England and Wales), while records of other birds in that district are ignored, as well as the whole of the information published elsewhere for other parts of Scotland. The immigrants reported on in detail in the volume are thirty-three in number, and twenty-one of them are also separately mapped, a graphic and useful assistance. The " unscheduled birds" (pages 160-181) and those dealt with in the " Notes on the Migratory Movements dining tlie autumn of 1909" (pages 200-260) are somewhat hidden, by not being named in the table of contents (there is no index), but there are some excellent short accounts of bird-movements under these headings. The reports on the Starling (pages 167 and 2331 and the Crossbill (page 231) may be .specially mentioned. Under the last-named the apposite remark is made that " if the true cause of these sporadic irruptions of certain species were known we might have a clue to the beginnings of the migratory instinct." Might this conjecture not be extended to include the sporadic movements of any species r j j j^ y^, TIDES. Tlie Titles and Kindred Phenomena of the Solar System. — Bv Sir G. H. Darwin. K.C.B.. F.R.S. Third edition, 1911. 437 pages. 46 illustrations. 8-in. X5-in. (John Murray. Price 7/6 net.) Successive editions of a book afford some test of the general need or approval for the work; it proves that the 30 KNOWLI.DGK January, 191J ;nilhor has siicoci'ilfd in prudiiciiiK a work thai iiitercstH "thiTS bi'sidrs himself. The book iiiuItT t'ciiisidcratioti is written in iion-niathciiiatical kiiiKiiaKf. Tlu- fcalnro of it is the singularly small amount of Icchiiiial formulae that a skilled author needs in describing pleasantly and interestingly such a highly scientific and complex subji-ct as the Tides. It recpiires a master-mind In render the subject easily intelligible to commnn folk .ind at the same time to preserve its standard so hii;li that no seientilic library can be elVicient without possessing a copy as a text-book or book of reference. The book has now become indispensable to the astronomer and the observatories, to the Kcodesist and Keographer: in short, to .ill who wish to know up-to-date facts of the cosmos, particularly of those important specks in the universe — the earth and moon. '1 here was good reason for a new edition of this work, and it is expressed in the author's own words, " Kven in so short a period of time as fixe years Ihc author had written the mamiscript for the first edition in l.S')7. tliouiih nol piiblislicd until October. KS9.Sj the aspect of some parts of niy subject had already changed considerably, so that in ly02 some alterations had become necessary, and now, after a further lapse of eight years, yet more extensive revision is needed. It is scarcely possible to revise an old book so as to make it into a new one. and it is not. perhaps, desirable to attempt to do so. because there is a certain interest in observing the gradual devi'lopment of scientific thought. It seemed to me, therefore, that the best way of incorporating into this volmne the recent advances of science was to add supplements to the several chapters, and only to make minor alterations in the original text." The chapters — the tidal theory perv.iding them — which are of more gener.il astronomical interest, or those beyond the regions of our earth and its satelliti-, arc those on Saturn's Kings (Ch.ipter .Will, originally Chapter X.\ in the first edition), I'igures of Equilibrium of a rotating mass of Liquid (Chapter .XI.Xl. Speculations as to the (Origin of Double- Stars iCh.ipter XXi. and the Kvolntion of Celestial Sy.steins (Chapter XXI I. the last three chapters being newer re- written. We notice an error in the chapter on Saturn's Kings at the foot of page .i.id. The discovery of the inner dark, or crcps, ring is credited to Bond and Dawes, as having been made in 1850; though these two eminent observers undoubtedly saw that ring independently for the first time, the credit of placing the discovery definitely on record should have been given to Dr. J. (j. G.ille, who had made a series of observations of this dark ring in 1838. These were published a few months later. Not the least valuable portions are the numerous references to the works of those upon which the book is based, and the index — the part of a book often scamped. A few other later references might have been added with advantage to some of the chapters. The first edition had three hundred and thirty-four pages of text in twenty chapters, and eight pages for the index, with forty-three illustrations ; the third edition is expanded to four hundred and twenty-six pages in twenty-one chapters, and ten-and-a-half pages of index, with forty-eight illustrations. Besides the three editions published in England, two have been published in U.S.A.. two in Germany, one in Hungary, and one in Italy. Altogether, a practical book of great interest, well arranged and printed, and at a moderate cost. SOLA )IS irkllAN'CES DURING X()\i: M I'.i: R, P>\ i"K\NK c. i)i:xni:tt. 'I HI-; Sun has shown more activity so far as spots « Professor F. \V. Very. He takes the great Andro- meda nebula as his standard ; its longer axis (neglecting faint outhnes) is 11 0'. He calls the distance of this nebula one "Andromede." and endeavours to find it on the following two suppos- itions:— (1) that its real diameter is equal to that of our Galaxy, its distance is si.xty Galactic radii ; (2) assuming that Nova .-^ndromedae belonged to the nebula, and that its intrinsic brightness at maximum was equal to that of a Galactic star of zero m.Hgnitude. its distance is twenty- five Galactic radii. On the latter assumption it is much smaller than our Gala.xy. Professor Very takes the mass of the Galaxy as equal to twenty million suns, and deduces that of the nebula as one and a-quartcr million suns. He takes the distance of'our Galaxy as sonn; sixty light- years, which appears to be too small, seeing that according to this value the Galactic stars should have large proper motions, and these in reality are very small. On this basis, and adopting the value twenty-five for the ratio of distances, he takes the distance of the Andromeda nebula as one thousand six hundred light-years. The smallest of the white nebulae have diameters about one six-hundredth of that of the .Andromeda nebulae, whence their distance would be a million light-years. He finds some evidence for the absorption of light in space from the fact that the smaller nebulae appear al.so to be intriusicallv fainter (surface for surface). He takes the trans- mission through a distance of one ".Andromede" as 0-996. Through six hundred and twenty-five .Andromedes it would be 0-082, or only one-twelfth of the light would reach us. Still another confirmation of the fact that the Galactic stars are on the whole beyond the region of sensible proper motion has been given in a paper by Mr. Bellamy in Monthly Notices for November. He has examined the larger proper motions of stars in the zone between 24° and 26° North Declination, from pairs of plates taken at an interval of some ten years, with the following result : — Mean Galactic Latitude. 4°-9 21 -2 .57°- J 58° -7 78° -7 Mean No. "f Stars per Plate. 315 247 128 85 74 Mean No. of P.M.s per Plate. 5-9 5-7 4-6 5-1 4-8 November 14th. X = 55\ Fkukk Mars. 1911. November 14th. \ = 94 . Sketches made at Flagstaff. NOTK.-Thc rugioil Only proper motions exceeding one-tenth of a second per annum are included. It will be seen that while there is a slight increase in the number of i)roper motions near the Gala.xy, it is not at all in proportion to the increase in the number of stars, showing that the Galactic stars lie beyond the region of easily detected motions. Professor \'ery is conscious of the difficulty, but endeavours to evade it by suggesting that the absolute velocities of stars in the Galactic system are smaller than in the Sun's neighbourhood, on the analogy of the diminution of planetary velocities, as their distance from the sun increases ; but it is to be noted that even if we grant this as regards their absolute motion, the motion of the solar system would still give them a large apparent motion. It is fairly well established that the sun moves through some four astronomical units per amunn. which, if unforeshortened, w-ould give a star at sixty light-years distance an apparent motion of one-fifth of a second per annum ; the Galactic stars certainly show no motion approaching this amoimt, whence it appears certain to me that the Galaxy is far more than sixty light-years distant, so that all Professor X'ery's estimates of Nebular distances would need multiplication by a consider- able factor. It is. of course, by no means certain that, e\en if the white nebulae are composed of stars, they are external Galaxies : they may well be miniatures of the Galaxy included within its limits. The fact that these nebnlae as a whole shun the Galactic Circle, and are somewhat clustered about its Poles, presents a considerable difficulty to the theory of their being external. iK froM. PHOTOGRAPHS OF MARS,— Professor Lowell has sent me three plates, each containing twenty exposures of Mars. The first was taken on October 11th by Mr. Slipher (longitude of centre of disc 70°). It shows Aurorae Sinus, Lacus Soils. Tithonius Lacus. .Argyre, and traces of several canals. The pair of plates taken on November 14th (longi- tudes 55" and 94° respectively! show the same general region of the planet (see Figures 40 and 411; their special interest lies in the white patch at the bottom of the disc, to the right of the polar cap, which Professor Lowell considers to be morning hoar frost : comparison of the two pictures shows that it does not move on with the surface details, but clings to the morning limb, and this certainly supports the hoar frost theory. The plates bring out much variety in the depth of shading of the Maria, and .show some indication of the canals across these ; the sketches given here KNOWLI.DGi:. January. 1912. are only rough, but may st-rve lo indicate the principal details shiiwn on the plates. .X recent journal of the Astronomical Society of Canad.i contains .1 reproduction of a beautiful photograph of Mars taken by I'rofessor Barnard at Verkcs in I'lO'i, Those taken in that year with the ►.'real relleclor at Mt. Wilson were very successful in showiut; the various shadiuKs on the Maria, but broke down in fuie detail : a refractor has the ,'idvanl:iL;(' in this respect. We have reached a sta^e when photO(;raphy lUH^^^ii" '" ^"■' '' '*-'■*' 'd in the vessel before applyiii); tin- Ifsl. When the air contains carbon monoxide in excess of 0- 1 piT cent., the papiT will shows siKns of darkening within .ibont one minute, while as little as O-Ol per cent, will aflect the pa|H'r within about eleven minutes. COMPOSITION OK SOMK i:.\KLV M.AICIIHS.— A paper has been read before the Chemical Societv by Mr. ]'.. C. Clayton [l^roc. Cliciii. Soc. U)ll, XXVII, 22')) in which are ^iven .some interesting; particulars of the characteristics and composition of some of the earliest matches put upon the market. The so-called " Promethean " matches, introduced in the e.irly part of last century by Samuel Jones, consisted of ;i mixture of potassium chlorate, sulphur and other substances, which was isjTiited by contact with sulphuric acid, supplied separately in a small gl.iss lube. Then in 1.S26-7, the first "friction lights" were invented by John Walker. The main constituents in these were sulphur, antimony sulphide and potassium chlorate, and they were ignited by being drawn between strips of sand paper. Their success led to the manufacture of similar " friction lights " by Samuel Jones (the originator of " Prometheans"), and to these he gave the name of " Jones' lucifers " or " Chlorate matches." The following analyses show the percentage composition of some of these early matches in use prior to the introduction of phosphorus matches : — Noii.phosphoriis .Malrf.cs. Sulphur. Pota-s- Chloraie. I.yco- Gum. Anti- mony Sulphide. Ferric Oxiilr. " Promethean'"" 24-7 34-9 8-8 31-6 Matches (1828) "F^ucifer" Matches I. 6-5 27-6 — 35-7 24-6 5-f) (1832-31 " Lucifer" Matches II. 12-5 41-0 — 24-9 18-1 3-5 (1832-3) * Ignited by dilute sulphuric acid coloured with indigo. Soon after the introduction of " Inciter " matches, the first phosphorus matches were manufactined. They were sold under the name of " Congreve matches," and were probably so called after Sir William Congreve, who invented the war rocket. These matches, large (piantities of which were made abroad, and especially in Germany and .Austria, contained ordinarv phosphorus, and also differed from the lucifers in being ignited by being " struck upon the box." The composition of two kinds of these matches, the first probably representing the earliest phosphorus matches sold in England, is shown in the following examples taken from Mr. Clayton's long table: — Pho>phorus .M.ilches. Or' <, , Polas- Phos. 1 S"': siun. phorus. P""'- Chorl.iie. Chalk Dextrin. Gum. Dye. German (about 1835) Austrian (1845-1850) 20-5 14-3 321 1 17-8 11-5: 371 8-0 25-1 — ii-i Tr.-ic: ,.f bliic .lyi-. (, i;( )1.( n,\. By G. W. TvKRKl.i., A.K.C.Sc, F.G.S. PLIOCICM- FLINT IM PLI:MI-:NTS.— Momentous dis- coveries of Hint implements have been recently made in East Anglia — one, by Mr. J. Keid Moir, in the detritus-bed at the base of the Ked Crag in Suffolk ; and another, by Mr. W. G. Clarke, at the base of the Norwich Crag in Norfolk. These sub-crag implements are described by Sir Ray Lankester (Meeting of Royal Society, November IdthI as of a novel ly|)e which cannot be associated with any yet known from other localities. This ty(M? is called the rostro- cariiiate or " e.tgle's beak," and includes also scrapers, haiiniiers. and large onesided picks. The ro.stro-carinale impleiiii'iils are compressed from side to .side, and are thus distinguished from the Chellian and Moiisterian typ;;s, which ;ire flattened like a leaf. 1 hey were manufactured prior to the period of severe glaciation, and are thus older than any previously known on etpially good evidence. On accotuit of the atTmities of its molluscs Sir R. Lankester is disposed to believe that the Red Crag should be grouped with the Pleistocene rather than the Pliocene. The race of men who made the rostro-carinate implements are believed to have lived near the sea in the time of the Coralline Crag. Some of the implements were washed into the detritus-beds at the base of the East .Anglian Crags, but others remained on the land surface, and were subsequently included in glacial sands and boulder-clays, in which a few have now been found. In view of the importance of the annoimcement. it is to be hoped that indisputable evidence will be forthcoming that the implements really came from the beds named, as there are so many possible sources of error attending the discovery of implements in deposits earlier than the Pleistocene. ORIGIN OF THE DIAMOND.— The fascinating problem of the genesis of diamonds receives further attention from Dr. O. H. Derby {Jotirn. Geol.. Oct. -Nov., 19111. who puts forward a new speculation as to the origin of the gem. As is well known, diamonds occur, at least in South .Africa, in pipes of volcanic origin which are filled with a peculiar ultra-basic rock called " Kimberlitc." This rock is inv.ariably much fragmented and altered, and contains numerous foreign inclusions (xenolithsl, both of igneous and other origin. The weight of evidence is in favour of the diamonds being assigned to the eruptive rock proper, and not to the xenoliths included in it. Dr. Derby believes that a positive, and perhaps genetic, relation exists between the diamond and the fragmental condition of its matrix, ba.sing his opinion on ttie experiments of Gardner Williams, who crushed twenty tons of the eclogite boulders or segregations from the Kimberley Mine without finding a single diamond. This association of diamond with fragmentation means that the origin of the diamond is to be assigned to reactions between the rock constituents, made possible by the explosive and disintegrating action of the agency that formed the Kimberley pipes. Under this view the exten- sive hydration and carbonation of the Kimberley rock is due to deep-seated pneumatolytic action rather than to atmospheric weathering. Kimberlitc from the deepest part of the De Beers Mine (2,('40 feet), still contains (i-.Sl per cent, of combined water, and it is improbable that this can be due at that depth to atmospheric weathering. Dr. Derby presents a new hypo- thesis of the origin of the diamond on the assumption of the deep-seated origin of the alteration of the diamond matrix. He believes that the Kimberlitc pipes were saturated with hot (possibly superheated) gases and liquids, and constituted huge crucibles in which carbon would he present at least in the form of carbon dioxide, and probably in other gaseous forms. Thus the material and soitie of the physical conditions for unusual carbon segregation would be present, and it is pos- sible that, under these conditions, diamonds would be formed. The suggestion is made that the nMe of carbon in eruptive phenomena generally would be an attractive subject for experimental researches such as could be carried on in the Geophysical Laboratory of the Carnegie Institute at Washington. GLACIATION OF NORTH ARRAN.— The sculpture of the mountains of .Arran. the most beautifid of the Clyde islands, has recently been studieil in detail by Mr. F. .Mort {Scottish Gcofi. Mdfi.. Dec. 1911.) These mountains consist of a mass of granite with a nearly circular outcrop; and whilst never reaching three thousand feet in height, constitute some of the finest mountain scenery in Great Britain, in consequence of their sharp spiry summits, serrated outlines, deep valleys, .and great precipices. This remark applies particularly to the eastern mountains grouped about Goatfell, To the west the Jam-akv. 101. knowij: nni-. 35 forms become soft, rounded, and full-bodied, the alliliide sinking to less than two thousand feet. This contrast is due to the fact that the western hills owe their smooth outlines to the work of the i;reat ice-sheet which once covered the island, whilst the hitjher Goatfell group became subsequently a centre of independent glacialion. Its originally smooth outlines have conse(|uently been destroyed, the rounded ridges have been narrowed into gashed and serrated aretes, great corries or cirques have been gouged out of the mountain sides as if by a gigantic cheese-scoop; whilst deep I' shaped valleys have been carved, in which the existing streamlets appear as almost ludicrous "" misfits," and whose tributaries form beauti- ful hanging-valleys. The .Arran mountains rise from a well-marked plateau at a level of one thousand feet above the sea. This plateau is built of such diverse rocks as Schist, Old Ked Sand- stone, Triassic, and Granite, and has a most immature drainage, presenting an example of extremely youthful topography. This is taken as proof of its recent origin. It is believed to represent the remains of a peneplain of marine denudation, and doubtless belongs to the one thousand foot platform so well developed in the adjacent Grampian High- lands. Mr. Mort reaches the same conclusion in regard to .\rran as does Professor W. M. Davis in regard to the Snowdon group, namely, " that a large-featured, round-shouldered, full- bodied mountain of pre-glacial time has been converted by erosion during the Glacial Period — and chiefly by glacial erosion — into the sharp"fe.itiired. hollow-chested, narrow- spurred moimtain of to-day." METEOROLOGY. By John A. Ci'ktis. F.K.Mkt.Soc. Thk weather of the week ended November 18th, as set out in the Weekly Weather Report issued by the Meteorological Office, was mostly dull and unsettled. Over a large portion of the kingdom rain was experienced daily, some of the amounts being very large. Sleet or snow were common in the N. and E. of Scotland late in the week. .Aurora was observed in Scotland on the 16th, and thunder was heard in Ireland on the 17th, Temperature was above the average in all districts except Scotland, N., the excess reaching 4°-6 in Knglaiid K. The highest readings reported were 60° at Hillington and 59° at Hereford. 1 he lowest readings were 24° at Baltasound, 25° at Nairn, and 26° at Kilmarnock. In Ireland the minimum was 35°, and in the English Channel 43°. On the grass readings down to 20° (at Llanganimarch) were obscrxed. Rainfall was in excess very generally, and was more than double the average in many places. At Tunbridge Wells the total for the week was 2-67-ins., as compared with an average of 0-7.S-ins. Bright sunshine was in defect in all districts except Ireland N., where it was normal, and in the English Channel, where it was just above. The mean temperature of the sea-water ranged from 41-0 at Kirkwall to 52-9 at Newquay. The week ended November 25th was cold generally, the defect as compared with average reaching 5-0 in Ireland S. The highest reading was 53' at Guernsey on the 20th, but at a number of stations' the maximum did not exceed 45'. The lowest readings were 21" at Balmoral and 22 at Birr Castle. On the grass very low readings, down to 10' (at Llanganimarch). were noted. Rainfall was in excess of the average in Scotland E. and England N.E.. but was in defect elsewhere. In Scotland W. the week was almost rainless, the district value being only 0-02 inches, as compared with an average of 1-19 inches. Sunshine was in excess in the Western districts, but was in defect in the English Channel and was about normal elsewhere. Valencia reported the largest aggregate, 33-2 hours (57%), while at Westminster the total was only 2-2 hours (4°b). The a\eragc temperature of the sea water ranged from 4()"-4 at Kirkwall to Sl^-S at Newquay. During the week ended December 2nd, the weather over the L'nited Kii\gdom was changeable, but not very wet. Snow and sleet were experienced in the North and East, and thunder was heard at Kilmarnock on December 1st. Temperature did not differ greatly from the normal. It was a little above the average in Scotland, England, N.W., and Ireland. N.; in other districts below it. The highest reading was 56°, reported from Glencarron, Hawarden Bridge and Markree Castle. The lowest readings were 20" at Nairn, and 2 P at Strathpeffer. Frost was observed in e\ ery district except the English Channel, where the minimum was 34^. The lowest reading on the grass was 17° at Llangammarch. Rainfall was below the average in all districts except England N.E. In England S.E. and the English Channel it w.is but little more than half the usual amount. There were no stations without rain, and at several places rain was measured on each day. Sunshine was scanty ; the sunniest district was England S.W.. with 17 hours (30%), but England E. had only 4 hours (8%). The sunniest station was Newquay with 22-3 hours (39%). Westminster reported 1-8 hours (3%)_ The mean temperature of the sea water varied from 40° -0 at Kirkwall to 48° -3 at Scilly and at Plymouth. The week ended December 9th was very unsettled, but with bright intervals. Snow and sleet were experienced in some Northern districts, and thunder accompanied by hail occurred at Westbourne on the 6th. Temperature was below the average very generally, the greatest deficiency being in Ireland S. The highest readings were 57° at Pembroke, and 55° at Cambridge and Dumfries, on the 3rd. The lowest of the minima was 21' at Balmoral on the 8th. The English Channel was again the only district which was free from frost in the air, although at Guernsey there was a reading of 27° on the grass. The lowest reading on the grass for the week was 12 at Llangammarch Wells. Rainfall was in excess in all districts except Scotland N. In England S.E. and S.W. and in Ireland S. the totals were more than double the average, and at many stations rain was measured on each day of the week. In spite, however, of the frequent and heavy rains sunshine was considerably above the normal in all districts, the percentage of possible duration ranging from 46° in the English Channel to 24^ in Scotland N., which was just double the average in each case. The sunniest station was Salcombe, 32-5 hours (58%). At Westminster the aggregate was 12 hours (22%). The temperature of the sea water varied from 39° at Ballantrae to 51° at Scilly. The week ended December 16th was mild and wet. Slight thunderstorms were reported, and Aurora was seen in Scotland on the 11th and 14th. Temperature was above the normal in all districts, the excess amounting to nearly 4 in England S.E., and the Mid- land Counties. The highest reading was 55° at Waterford with 54° at several stations. The lowest of the minima were 23° at Balmoral. 27 at Kilhirney, and 29 at Nairn. At no other station did the temperature fall below 30°. and indeed in six out of the eleven districts into whi<:h the L'nited Kingdom is divided for Meteorological purposes the temperature did not fall below the free;!ing point. In the English Channel the lowest reading was 41°. On the ground the lowest tempera- ture reported was 20 at Balmoral. Rainfall was greatly in excess, except in Scotland N. Falls of more than an inch in twenty-tour hours were frecjuent, and at Crathes the fall on the 15th amounted to 2-03 inches. At many stations the total for the week was more than double the average. Sunshine was also in excess of the average over the greater part of England though slightly below in Scotland and Ireland. The sunniest district was England E., with 15 hours (29%) ; the sunniest station being Torquay with 19-3 hours (35%). At Westminster the total was 10-9 hours (20%). The temperature of the sea water ranged between 40° and 50°. KNOWI I ix.l January. 191; Diiisal surface KAIM AM. AND I'lMIMSIS. — A rrsi-aiili ri>ii(liK'li->l l>y I'l. William (tordnn, pliysicinii In tlic Koval I)«-voii aiicl l-!xfliT lln^pilal. has li'd tlic author (n some inter ostiiiK Mint iiniMirlant coiic-liisiiiii'' with rrKard to the infliieiuc of rain- bearing winds upon ihi- prcvalriiiT of phthisis. Takiii)^ certain Kiiral Sanitary Districts in Drvonsliiri'. h^ classified the parislies comprised in the si'veral areas according to theii exposure to the \V. and S.W. winds, which are in Devonshire the rainv winds, into I. slu-ltered parishes, II. cxiHised parishes, ,ind III, imper fcctly sheltered parishes, and then rarefnlly collated the deaths from phthisis in these parishes during •! scries of years. To his (jrcat surprise he fomid that the death-rale in the parishes exposed to W. and S.W. winds was Kenerally double, sometimes more than double, that in the parishes sheltered from those winds, and this irrespective of the atiioutit of the rainfall in the variou> places. Thus, of two contiguous parishes with a hill between them the parish on the windward side of the hill was found to have twice as many deaths from phthisis, per thousand of the population, as that on the side sheltered from the S. and S.W.. but exposed to the N. and E., and this although the amount of the rainfall on the leeward side of the hill was in many cases greater than that on the windward side. The areas selected were situate, two in the northern part of the county and two in the southern part, and the results were so consistent as to justify further inquiry. This further inquiry was conducted both in detail and on a broad scale, and the results arrived at fully confirmed those first reached. In the wide inquiry the various counties were taken as units, and subsequently larger areas still ; in the detailed incjuiry the Citj^ of Exeter was taken, street by street, and both lines of research led to the same result, namely, that the important point to consider in the choice of a residence for persons suffering from phthisis is the incidence of the rain-bearing winds of the locality, exposure to which is a more serious factor than the altitude of the place, the character of its soil, or even tlic amoimt of its rainf.ill. MK ko.SCoi'W Ky (). 15. Ji;ciivi;, FiGiKi- 42. X 44, sliowing the processes. Figure 43. Side view of Palpus. X 120. Inside, showing the two teeth . Drawn from a male specimen. Male and female alike. FiGlKK 44. ;>f fourth leg. Figure 45. Method nf carrying palpi in front. Drawn from the front of an unmounted specimen. X ir>0. with the assistance of tnicroscopists the followiiifi Arvmur The Rkv ClIARI.RS C. Ban . E. W. I'RTON. H. Ca C 'lEI.D. BoWEI.I., U. '.Soar, .\RTIIl'R KabI.A Richard T. I.k Chas V. Rm ss 1). l..SroiKKiK F.I,.S., K.R.,M.S SD, F.R.M.S. WIS, F.R.M.S. f.LKT, I'.R..\I.S .D. F.R.M.S. AN INTKKKSTINC, ICAUTM MITE f.N- ui:c<)kdi:d in <;keat hkitain.— on.- Summer day in 190'^ 1 was .seeking in my gar- den for some fresh mites or spring-tails, and so on, when I saw on the stone steps leading FiGURi-: 46. Posterior margin ventral surf.-ice of male, show ing the comb-like arrange- ment of bristles, X (.4. h^iythiicanis parictiiiiis Ilerm. up to the house, a mile (Figure 42) moving at a very rapid pace, and progressing in ipiile an unusual manner. It was advancing in a /ig2ag manner, but in the form nf curves, each curve being about five to six inches long, and advancing about one to two inches at a time. Sometimes it would make a wider sweep of about half a circle, and occasionally, when apparently it came across an active prey, it would whirl round in small con- centric circles with such velocity as to envelop and secure if. and sometimes it would stop so sud- denly that the eye was carried on and for the moment lost the mit<'. .As an instance of the ferocity of this mite. I saw a Spring-tail. I ike believe a Degecria, several times the size of the mite, resting on a window-sill. The mite was advancing in its usual zig-zag manner towards it, but not seeing the spring-tail until within six or eight inches from it : then the mite rushed at the springt.iil. I'or a moment the turmoil was something to see, but it ceased as suddenly as it had begun, the mite was alone, the spring-tail having escaped with a motion too rapid for the eye to notice. Ha\ing moved in March. 1910, to another part of Plymouth, I was afraid I had lo.st my little visitors, especi- ;illy as I did not find them at the old home, which I occasionally visited for that purpose : no doubt it was mainly owing to the inclement year, but to my delight in the early summer of this year (19111 1 found them busy on my window-sill, and again on a low wall underneath m>' window. .Apparently they nested in the border boll - Hower iCaiiipaiiiila car- paticiiK which I had sent up to my new abode, a singular coincidence th.at this mite living amongst hun- dreds of blue bells, should be fur- nished with ears. I found on placing the mite under a low power. X 35. that it was a dark orange-red mite with brown markings, but with two perfectly white ear-like processes lin shape triangular), situated immediately behind the eyes. Then putting it under X 200 I saw a beautiful comb- like arrangement under and across the end of the abdomen, and projecting beyond it. This I found afterwards to be the male. The female is in all respects like the male, except it is without the comb-like process shown in Figure 46. I h.ive always found it active, .seeking its food on stone, .and never on flowers, tiower bed, or gr.iss adjoining. I have also found them on my bedroom window-sill, about twenty feet from the ground, where a p.air had taken up their abode between the wood and stone-work, so 1 hope next summer to have a further and better opportunity of studying them. The front of the house over which they travelled is built of stone. It is apparently Erythactinis pdrictiiiiis. Horm.. but neither Hermann's figure KS04. nor Koch's 1835-41, nor Herlese's. h.ive the ears which is such a beautiful and distinct ch.aracter in tliis mite, so it would appear to be: — .As Erytha- earns parictiiiiis with ears. Super family. Jantarv. IQtJ KXOWLKDGE. 37 Tiombidoidea : family. Erythracidae ; genus, ICrythracus (since altered by Horlcse to tirytliactinis. because the type Hrytliraciis is a Kliyiicholopliusl. Kefereiices: — Hermann. J. F., " Menioire .Apterologitiue," patre J7. Table 1. Fisjnre 12. Strasburg. 1804. Koch, K. L.. "Deuschlands Crustaceon," 1S35-41. 16. 2J. Herlese, F., 11, No. 4. Figure 2. The length of the mite is 0-96 millimetre. The figures to ilhistrate mv note were Uindlv drawn hv Mr. Chas. D. Soar, r.U.M.S. \ ^,■ V .\. \\ . .Alabaster. I).\KK GROUND ILLIMIN.-VTION .AND L"LTK.\- MICROSCOPIC VISION.— The letter on the above subject by Mr. F. Leitz is of considerable importance, for it is eminently desirable that a proper understanding of the province and limitation of the accessory appar- .itus used in the production of dark ground illmnination should be clearly defined. Particularly striking is the fact mentioned by your corresspondent, th.it neither dark ground illumination nor the so-called Ultra-Microscope is a means of enhancing the resolving power of the Microscope. Mr. Nelson pointed this out some considerable time ago, and it has now been ascertained that for an objective to utilize its full resolving power the numerical aperture of the Dark Ground Illuminator must be three times that of the Objective. .As under present conditions the maximum numerical aperture of the Illuminators is 1-35. it follows that the effective aperture of all Objectives exceeding •45 is reduced. There is actually a greatci- resolving power with dark ground illumination with Objectives having numerical apertures in excess of -45. but it is very substantially less than that which is yielded with direct light ; so much so that if we take 1 -35 as the limit of numerical aperture for both condenser and objective, the resolving power obtainable with dark ground illumination is approximately th.at yielded with a numerical aperture of •65 with ordinary direct illumination, while if the practical limit of the objective be considered, namely 1-0 N.A., in conjunction with a condenser of 1-35, the resolving power obtained is only ecpial to that of an objective of -59 with direct illumination. It therefore follows that the perception of fine structural detail is not so nmch a feature with dark ground illumination as the increased contrast afforded, and the practical advantage of the use of high powers lies chiefly- in the greater magnification. The well-known phenomenon of a streak of sunlight passing through a small opening into a darkened room revealing dust particles which in full daylight cannot be seen, is the explanation of the effect produced in microscopical dark- ground illumination when minute particles otherwise invisible are revealed, and even with so simple a piece of apparatus as the spot lens with a one-inch objective, starlike objects and specks which by direct illumination would be invisible are clearly seen and come under the category of "ultra- microscopic." .And so through the whole range of dark ground inunersion condensers, and finally the special apparatus known as the " Ultra- Microscope " the same law applies, only the method differing, and there is the same limited resolution that is implied by the physical limitation of the total numerical aperture of the condenser referred to previously. Undoubtedly great confusion has arisen in the minds of microscopists in consequence of the multiplication of dark ground illuminators of various kinds, especially those which have enabled objectives of high magnification to be employed, and for the sake of clear understanding, and to avoid any chance of confusion, it would be well to sharpl\' differentiate the apparatus into three classes : — -, 1. To comprise the Spot Lens and all the means until recently provided for low power dark ground illumina- tion, which might be classed as '' Low Power." F'IGURE 47 2. .AH the modern Illuminators which have for their purpose the use of high posvcr objectives and particularly the revealing of living bacteria, and so on. which could be classed as " High Power." .And linally, the entirely distinct arrangement which depends on illumination at right angles to the optical axis through a slit, which could be known as the " Ultra- Microscope." I commend these brief notes to the consideration of your readers, with the hope that someone more capable than myself may pursue the matter further. .. . (-|,,>t-c .A Ni:W MICROSCOPE.— W. Watson 5; Sons, Ltd., have recently introduced a Microscope of new design, the " Bactil Mk. IV." which follows the lines of some well-known Conti- nental models, but combines the special features which distinguish ,all the Watson Microscopes. Sec Figure 47. It will be noticed from the illustration that the fine adjustment is set on the side of the limb, the rotation of the controlling milled head being read on a divided drum. This milled head actuates a lever set in a vertical position. The freedom from complications, certainty of action, and the very slow movement that can be obtained is well known in the lever form. The mechanical stage is not of the usual .ittachable kind, but is built to the instrument and gives a horizontal range of movement of two inches. .A very neat feature of this stage is the method of gripping the object slip. Hitherto this has been dependent on a spring action pulling ilown a curved finger-piece. This has alwavs luiin open to the objection that the immersion oil, especially if thick, exercised a retarding mrtucnce on the slip, and this, pressing against tlie spring referred to. caused it to give verv slightly, with the result that when high powers were in use there was an apparent loss of time on change of direction of the mechanical screw of the stage. This is obviated in this new pattern, the finger-piece being set by means of a milled head, and being iunnovable excepting by its means. Hy an ingenious arrangement the whole of the stage can be removed from the dove-tailed fittings and a plain stage substituted for it if desired. The substage is of the regular English pattern with rack- work to focus and screws to centre. It also lifts aside from the optical axis. The sprung fittings to frictional surfaces, the large body tube, the long range of coarse adjustment for use with low power objectives, the advantage of which is so well-known, are retained in this model. It is of solid and handsome construction throughout. .APP.ARATUS TO FACILITATE THE ILLLMINA TION OF OPAOUE OBJECTS WHEN VIEWED HV THi; AID OF THE VERTICAL ILLUMIN.ATOR (Figure 48).— This apparatus, suggested by .Mr. J. I!. Barnard, l-'.R.M.S.. consists of a snuill right angle prism, fixed to an arm, which is clamped to the nosepiece of the microscope by the screw of the vertical illuminator, and has universal movements. It will be found most useful when photographing opaque speci- mens such as metals, and so on. In use the Microscope Stand is placed in a horizontal position and the illuminating beam thrown by the aid of a bullseye condenser upon the right angle prism; it is then projected through the diaphragm of the vertical illuminator, and so on through objective to specimen; the diaphragm of vertical illuminator must of course be directly under the right angle prism. By this means of illumination the position of vertical illuminator may be varied when objectives of different power are used without the beam of light being altered, one of the inconveniences experienced when the vertical illuminator is illuminated from the side, and to overcome which many metallurgical micro- scopes are provided with rack adjustment to the stage. In 38 KN()\VLi:i)r,r: Jam'arv. 1912. pliotoKrapliiiiK opaSJ4.ind 1838. Mr. Rousselet also described another microscope from India, lent by Mr. A. H. Lethbridge. It was a combination of a pocket tele- scope and microscope. The eyepiece of the telescope being renio\ed and screwed into a "drum" form of stand consti- tuted a low-power microscope of itself, and on removing the field lenses of the eyepiece " French- buttons " can be screwed on giving higher magnifications. The name inscribed on the apparatus is Charles Nephew and Company, Calcutta. The date is uncertain, but would be some time after introduction of the ■■ French-button." The Society exhibited, under Microscopes, a number of slides ^— of Rock-sections from .\ustra- S> lasia, presented by Mr. H. J. Grayson and cut by him by his improved apparatus. Mr. J. E. Barnard read a paper on " A Geometric Slide Photo- micrographic Apparatus." Mr. Barnard said the apparatus was I'iGl' designed on the principle of the geometric slide throughout, as enunciated by Lorii Kelvin and Tate. The base of the apparatus was formed of two castings designed on the girder principle, braced together at each end and in the middle. The portion to carry the microscope was also formed by a pair of castings braced together in the same way. Great rigidity was obtained, and the whole apparatus would move together if subjected to shock or vibration. Rods were fastened down on the top of the castings to support the apparatus, and the camera slid along these on two V grooves on one side and on a plane surface on the other side. The camera was supported on vertical rods fixed on the geometric slides. The apparatus could be used equally well as a horizontal or vertical camera, or at an angle of 45'. A paper on Fr/rfcn'c/a, by Rev. Hilderic Friend, F.L.S.. was read. The genus Fridcricia was created by Mich.aelson, in 1889, to receive certain species of Knchytraeids, eleven in number, possessed of dorsal pores, and having setae of unequal lengths. In 1895, Beddard reckoned twelve species, but not one was known as British. Moore, Friend and others added to the list which in 1900 stood at twenty-one. Bretschor, Issel and others then took up the study, and at the present time some seventy or eighty species of Fridcricia are known to science. The largest is F. nianna Friend, which has been found in England, Ireland and Scotland, but so far has not been reported abroad. The author, whose researches into this genus began in 1896, here reports no fewer than thirty species found up to the present time in the British Isles, Some of thes- K 48. moie ? Several of the more important of these diseases were described at length and an interesting account was given of the prophylactic measures adopted. One of the first problems to be solved in this connection is the distribution and life history of all blood-sucking insects, an enormous task, but one that is being slowly and surely accomplished. ORNITHOLOGY. By Hrcii Boyd \V.\tt, M.B.O.C. WILLOW GROUSE IN SCOTLAND.— Last shooting season (1911) three white Grouse were shot at Glendaruel, .-\rgyllshire. and seem to have been something of a puzzle to the shooting party at the time. It is explained, however, that on the neighbouring estate of Glenstriven some Rypcr iDalripii. Swedish) or Willow Grouse {Ltigopiis ttThiis) which had been sent from the far north of Sweden, were put down some years ago in the month of .April. They were placed in an enclosure on the hill with one wing slightly clipped, but they soon escaped and were scattered about the country. The remains of two or three, killed by hawks, were found; and those now reported shot are probably others which survived till then,— (T/u- Field, 18th November, 1911. page 1129), Our native Red Grouse (L. scoticiis) and the Willow Grouse have separate geographical ranges, but they are of common origin and the last-named might well establish itself as a breeding species in Scotland, given the opportunity, to which ornithological purists are strongly averse. It has. I I J \Nl\UV. 1")K KNowiJ-.nr.i:. 39 houfver. been tinned down on several shootin.!,'s. and in Banffshire, in 190sed Id HkIiI fur a time varvinR from five minutes in a bri(!l)t liKht to twenty minutes or more in a dull one. How ever, as the chauKe bronchi about is a visible one. the progress of printing may be watched. ex.nniiiinK the print in some wcii- sliaded position : especially so is this necessary with paper prepared with the urcen ferric-aumionium citrate, on account of its increased sensitiveness. If ordinary negatives are used to print from (and excellent results can readily be obtained in this wayl care umst be taken not to over-expose: in fact, the printing must not be carried to snch a stage that the det.iil in the hghts becomes visible, otherwise a general flatness of the picture will result. The negatives employed must be fairly strong ones, it being useless to attempt to use poor thin ones. The change in colour during exposure to light is from a greenish-yellow to a pale greyish-brown, a little experience soon enabling one to judge when the printing has been carried far enough. On removal from the printing frame development may take place at once, or the paper may be placed in a book until a more convenient time. Experience, however, shows that too long ;i time should not be allowed to elapse between the two operations. In order to develop the print it is laid face up- wards in a porcelain dish, and a solution of potassium ferri- cyanide (red prnssiate of potash) of about twenty grains in an ounce of water poured over. Development is almost instan- taneous, the print assuming a fine blue colour due to the ferrous salt resulting from the action of the light reacting with the ferricyanide of potassium, and producing a pre- cipitate known as Turnbull's blue, having the composition Fei Fe-jCyij. After development the prints are placed in water containing a little sulphuric or hydrochloric acid, then washed in several changes of water and dried. Prints made by this process are very stable, although soaking in water certainly weakens them. A variation of the process may be made by applying to the exposed paper a dilute and neutral solution of gold chloride, when a purple image results, owing to the ferrous salt reducing the gold salt to the metallic state. Sir John Herschel gave the name of Chrysotype to these prints. A variation in the method described above by which blue prints may be obtained direct without development may he made by mixing together the ferricyanide of potassium and the ferric salt, and applying the same to paper. The following will be found a good formula : — 1. Potassium ferricyanide ... 60 grains Water (distilled) ... ... 1 ounce 2. Ferric ammonium-citrate... ... ... 70 grains Water (distilled) ... ... ... ... 1 ounce These two solutions should be mixed together and kept in the dark. When required for use a little is taken and .spread over paper, as already described, which when dry is ready for use. When the .action of light has gone far enough, " which is ascertained by examination," the print is removed from the frame and placed in water containing a few drops of sulphuric acid, and afterwards washed in several changes and placed to dry. To make uranium prints the same procedure as described above is employed, using a strong solution of uranium nitrate of about one hundred grains in one ounce of water in place of the ammonio-citratc of iron. Development of the prints with potassium-ferricyauide gives brown i)rints. If we mix uranium and the iron salt, and apply this to p.iper, a grey print results on development; in fact, mixing of the .salts in varying proportions is found to give, in many cases, rather pleasing results. EXPOSl'RE TABLF FOR J AN'l'AKY.— Although weather conditi(ms during the next month or two may not be altogether conducive to outdoor photography, there may be occasions when opportunities present themselves for this class of work. We therefore give a table containing a few exposures that may be foinid useful. The calculations are made on the aclino- graph for plates of speed 200 li. and D.. the object a near one, and lens aperture I" If). Day of the Month. 1, tn.- .-1 |p ,-. of the Light. 11 a.m. Ui 1 p.m. 10 and i. 3 p.m. Kemarks. Jan. 1st Bright Dull '4 sec. •8 „ '5 sec. 10 ., 10 sec. 20 .. If the sub- ject be a general open landscape take half the exposures given here. Jan. 15th Bright Dull •3 sec. ■6 ., '4 sec. •8 .. '6 sec. 1-2 ., Jan. 30ih 1 Bright ,. Dull •2 sec. •5 ,. •3 sec. ■6 ,. •5 sec. 10 .. I'll\ SIC.S. Hy Alikhd C. G. Egertox, B.Sc. THF.KMOSTATS. — The Faraday Society's Meetings are always marked by a degree of general usefulness, interest, and enthusiasm which is sometimes lacking in the proceedings of older societies. On Wednesday, December 6th, among the subjects for discussion was that of the construction and work- ing of thermostats. Thermostats are arrangements for main- taining temperatures constant over a long period of time and are most necessary accessories to the study of most physico- chemical processes. A thermostat consists generally of a bath of liquid which is maintained constant in temperature by means of a heater placed either inside or outside the bath. The heater, if used inside the bath, consists either in a bare electric resistance wire or an electric lamp ; if used externally the heating is usually accomplished by means of a small gas burner. In each case some form of thermo-regulator, which .switches on .ind off the current or turns the gas up and down, has to be employed. This thermo-regulator usually consists of a closed tube of liquid with low specific heat, high expansion coefficient. and small density which expands on rise of temperature : the litiuid then presses on one side of the mercury contained in a rtube, which on being raised in the other limb of this tube, closes either an electric circuit or the end of a tube through which the flow of gas to the burner is passing. In the first case, the electric current actuates an electro-magnet which switches out the electric heaters ; in the other case the supply of gas is automatically cut down by closing the end of the tube mentioned and can only issue through a small opening in the side of this tube. An efficient stirring arrangement has to be used in the baths, otherwise a constant temperature cannot be maintained. These stirrers are constructed like a " screw " and are actuated by means of an electric motor. Dr. Lowry has improved the thermo-regulator by making the tube containing the expanding liejuid (usually toluene) as large as possible, so that the maximum amount of surface is exposed : there is then very little lag in the action of the regulator. This is accomplished by making the tube of spiral form. Dr. Marshall gave a number of valuable hints as to the working of electrically controlled thermostats. The form of electric heater he advocates, is a form of elongated electric lamp which is switched in and out as before described, only the thermo-regulator actuates a relay which then switches out the main circuit ; the relay being actuated by a single secondary cell kept permanently on the charge. A relay is a sensitive electro-magnet which responds to a weak current and makes an electric contact, which brings into action an electric current from a stronger source. The object of this is to obviate pernicious sparking on breaking the con- tact at the mercury surface of the thermo-regulator. Dr. Marshall also described a method of employing an ice thermostat for maintaining constant temperatures from 12 C to 0 C. This type of thermostat belongs to a diflcrent class, in which advantage is t.akeu of the fact that substances melt January. 1912. KXO\VLi:i)r,I- 41 anti boil at constant temperatures. Mr. Honsfield described a temperature rej^ulator for use in an air bath. It consists of a larKe bulb of tjlass containinK hydrogen. When this hydrogen is raised in temperature it expands and increases the pressure on a column of mercury in a barometer tube. When this occurs an electric contact is broken which switches out the electric heater. The mercury does not get attacked, because the circuit is broken in an atmosphere of hydrogen. It is not easy to obtain a satisfactory method of maintaining ' 'instant low temperatures over a long period of time. There .ire a limited number of substances which can be used to maintain constaut low temperatures, e.g., boiling sulphur dioxide ( — 10°C), boiling liquid amnionia ( — J3 C), boiling sulphuretted hydrogen ( — 61 ''O. boiling nitrous oxide ( — 83° C), and boiling oxygen (185° CI; also melting ether, melting nitrous oxide, and various " freezing mixtures," such as solid carbon dioxide and ether. But in all these cases a considerable quantity of the pure liquid is required, and the li(|uefaction is a troublesome process. F"urther, if these liquids are contained in a Dewar vessel, they supercool themselves unless evaporated by an electric heating arrangement. The writer has recently been employing an arrangement for maintaining temperatures constant over a range of temperatures between +80 and — 150°C, but has not yet published the method, as the details are hardly yet worked out. The general principle is that the thermometer, on rise of temperature of the bath liquid, makes an electric contact which switches in a heating coil situated in a closed bulb containing the bath li><^I >""P '"'" "'"i^li •' I'ts. has proceedt'd further." Mr. Iliiilou has paid considerable atleiilion to the dentition of the shrews, and it may be useful to note the formulae which he regards as most accurate:^ I'or Sorcx: — i. 1.2.3 1 I'or .Woiiiys : — i, 1.2.3 1 1 431 pm. — c. — pm 123 1 123 4 . . 1 — n 1 123. 123' I)()|-'S .A SN.ML SEK? — I'ield observations on the \ine- y.ird snail. Helix pnmutia, sui,'gcst that the aniin.il avoids the lil^ht. WillemV laboratory c.vperiments. on the other hand, suggest that it prefers the light. Professor ICniile Vutig, of Geneva, has re-investigated the (|Uustion, and finds that both these conclusions are wrong. He made over two thousand observations on one hundred and seventy-si.x snails, and found that they were <|uite indiflferent to all sorts of light-stinuilus, that they do not prefer lighted or shaded areas, that they do not see obstacles in front of thcni. and that their eyes have no visual significance at all. i:X()TIC CKL'ST.ACE.A IN BO'IANIC C.AKDKNS.— K. Menzel calls attention to the opportunities of studying exotic animals without leaving home. In the palm-house tank, in the Hot.anic Garden at Basel, he found an exotic Cypris (or Steiiocypris^: Outside he found Cyprctta [Cypriciopsis^ globulus Sars. which has been described from .Austraiia. I'nder flower-pots with earth brought from Java, he foimd what seems to be .1 new species of Orclicstia (O. sciini). donbtle..;s of e.xotic origin, and interesting in being thoroughly terrestrial. .ASSOCIATION or SLRKKITKS AND DKO.MIA.— .\ bright orange sponge iSiihcritcs doniiiiiciild >. is often found surrounding the gastropod shells inhabited by hermit- crabs, but the association has not been sufhciently studied. The sponge is unpalatable to many animals : it is full of strong flinty needles, and it has a strong odour. .At the Naples Zoiilogical Station Signor Polimanti has been recently studying the associati(m between the Snberiles and a crab iDroDiia vulgaris). He has made this much ipiife clear, that the crab takes the initiative in getting the sponge on to its back and that the sponge affords its partner an effective protection against the appetite of cuttlefishes. SELF-CLOSING PLANKTON NET.— Professor C. A. Kofoid describes a new model of Plankton net which he has tested extensively. The advantages which it has over other models are the following : — It can be opened or closed by the operator at any desired level in the sea. and it is not liable to interference from outside conditions. There is perfect and continuous closure of the net during descent and ascent. Nothing can enter, nothing can escape, unless the operator opens the net. The possibility of horizontal towing makes it feasible to effect a precise exploration of stratified waters. The vertical migrations of pelagic organisms can also be studied more elTectively than before. The opening of the net is free from bars and ropes, which tend to ward off the more active animals. Professor Kofoid also describes a new self- closing water bucket, by which it is possible to collect twenty litres from any desired depth. NOTICKS. A METEOROLOGICAL CATALOGUE. — We have received from Messrs. H. Sotheran and Company, an interest- ing catalogue of books on Meteorology and Terrestrial Magnetism. This is a comprehensive list of books on the subject, dated from the year 1269 to 1910. and includes the works of such pioneers as Descartes. Gilbert. Boyle, and Dalton. Some of the earlv books appear but seldom in sale catalogues. In addition there is given a list of books on .Aviation and of periodicals and publications of learned societies. SECOND-HAND INSTKU.MENTS.— \Vc have received Mr. C. Baker's January list of second-hand instruments for sale or hire. It consists of ninety pages and from it luany of our readers should be able to choose, at a reasonable cost, apparatus for which they might not care to pay the full and original price. This list deals with telescopes, microscopes, objectives, cameras, and lenses as well as less generally used apparatus, WHITAKER'S ALMANAC— We welcome the forty- fourth annual volume which has appeared under the title of " Whitaker's Almanac." As it is or should be on everyone's writing table, we can say nothing which will make those who know it appreciate it more, while to those who have not made use of it we can only offer our respectful sympathy. /ADKIEL'S ALMANAC— This contains matters of interest to our astronomical readers, though m.ainly devoted to the astrology and predictions which may be based upim it. Messrs. Simpkin, Marshall & Co. are the publishers. THE YEARBOOK OF SCIENTIFIC AND LEARNED SOCIETIES. — This, though primarily a book of reference, is interesting to glance through, while the lists of lectures given before the various societies offer useful suggestions to officials of institutions, and to lecturers who are looking out for new subjects. It should be on the shelves of evcrv library and public institution, and is published by Messrs. Charles Griffin it Company. Mi:TAI.LrK(;iCAL MICROSCOPES.— The microscopic Lxaniination of metals now forms such a very important branch of engineering industries that Messrs. R. and J. Beck. Limited, have brought out a special catalogue dealing with the examination and photographing of metals. The hst also contains descriptions of cameras for taking photomicrographs, and machines for grinding and polishing sections. A special micro.scope is illustrated which has been designed for the examination of the surfaces of the various kinds of blocks used for printing with letterpress. "W IIOS WHO" AND ITS COMPANIONS.— The editor of "Who's Who" continues each year to discover a number of new people who are playing an important part in the world, and as a result the annual volume which Messrs, A. & C. Black publish becomes larger and more useful, while its price remains the same. The " Who's Who " Year Book, con- taining matters of interest crowded out of the original volume, is still issued annually by the same firm, which publishes also, for writers and authors, another annual volume with the intention of helping those who are getting their living by contributing " copy " or illustrations to the periodical press, " The English Woman's " Year Book comes from the same source and contains much general information, as well as a great deal concerning education, occupation, and entertain- ment of special interest to the gentler sex. SCIENCE REFERENCE BOOK AND DIARY FOR 1912. — Messrs. James Woolley. Sons & Co.'s Science Reference Book and Diary has again been re\ised. Not only does it consist of a diary, calendars for the past and coming years, a dictionary of daily wants, a lighting-up time table, and list of scientific societies, but it has a second part, with a dift'erent opening, which contains a reference book on all matters dealing with science, such as atomic weights, physical constants, and test solutions, while scientific terms are explained, and other matters considered of importance in the everyday life of .scientific workers. The price is Is. 6d., which is no greater than that of an ordinary diary got up in similar stvle. Knowledge. With which is iiicorporati-d ll^irdwicki - ^tRiicu tiossip. .iiui tlu- Illuslraud Scientific News. A Monthly Record of Science. Conducted In- Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A. li:i!Rr.\KY, 1912. THE GRAPHIC EXPRESSION OF SENSE. i5v .\NN.\ 1)i:an: lU'TCHMK. Tm: art of Typography has been, during the last twenty years, almost revolutionised. Entirely new processes have been in\ented. and it is claimed by the School of British Printing that it has made advances to an extent almost unparalleled in the recent history of any industry. Yet. with all these improvements in machinery and appliances, no similar ones have been made in the notation of the English language for four centuries, and we are confronted almost evePk" hour of the day with the anomaly of a fifteenth-century print to express tile complicated ideas, and define the accurate scientific conceptions, of the present day. Writing and printing as practised by civilised man are degenerate graphic arts, and while \ery much thought and money have been e.xpended on mechanical pre- cision, this inost obvious fact has been overlooked, that if a drawing or symbol is unsuited to indicate sense or meaning.it is not only useless, but misleading, to ornament it or render it attractive to the eye. It may be objected that " suitability " is a matter of opinion and taste, but this is not the case. The Ogee curve as assumed by the swan's neck is a beautiful because a suitable form : a walking-stick designed on this model would be a hideous object, because this form is wholly unsuitable to suggest strength or support. The laws of graphics or the expression of sense b\' the graphic arts are, like other physical laws, the ascertained causes of invariable phenomena. It was the opinion of the late Professor Max Miiller that until Language is studied as a physical, rather than an historical science, no practical improve- ment can take place in the means adopted by man for the expression of his thought or meaning. The methods of investigation employed b\- the physicist are to accurateh" observe objects, to record facts and phenomena in their order of importance statistically, and then gradualh', by the aid of the itnagination. to guess a cause or invariable law which might account for the recurrence of these phenomena. He then proceeds to eliminate one after another those hypotheses which do not consistently explain the phenomena, until the true, or at least a workable law is discovered. Following this scientific onler we may deduce the follow ing grapliical laws. Mail is a silciit-rciuliiiii aiiiiiuil n'lio dnncs his idccis. — This definition of man is as true now as in the hieroglyphical age of the ancient Egyiitians. Man has the power of communicating his ideas b)- s[)eech, in common with many other animals, but as far as we know there exists no other creature who draws his ideas. Therefore writing, or symbolism, is just as inevit- abl\- a natural product as the honey of the bee, the coral island, or the spider's web. Graphic symbolism is a function of the brain of man. Symbols control his actions, are photographed u|)on his brain, are associated with all his intellectual eflbrts, and from their influence he can by no means free himself. Man has been from time immemorial a slave to the trtiditional symbols which he employs; he has no more power to change these symbols than a magpie has to alter the shape of its nest. Notations grow like trees, in accordance with graphical, which are physical laws. The brain of man is developed, and its nervous telegraph apparatus is differentiated and taught to function, b\- the traditional symbols which surround him on all sides. Pnit man is not aw are of this slavery. The mathema- tician imagines himself free to construct theories, to develop his ideas at will, and to express them as he chooses, little thinking that he himself is a slave to traditional sxmbols and absolutely dependent upon a paper memory for his calculations, and that were 44 KNOWLI.DC.I:. FKIlRrARY. 1912. it not for liapiJV arcidcnts of notations, inatlu'inatical scieiKc would not exist. Tlie mechanical trick of placing; twt) little horizontal strai^iit lines one iinder- neatli the other su}j(;ested the idea of negative nmnlKTS. and is the origin of the Hinomial Theorem. .\ll the ahsiird explanations of teachers and text- lH)oks are due to ignorance of the fact that the sign or mark precedes the idea. Sciences. Keligious Philosophies, both false and true, owe their origin to symbols, yet no subject is so persistently disregariled as the natural history of man as a " symbol-drawing animal." The graphical expression of meaning is now no longer under the control and subject to the correction of the hand of man. but this function has been delegated to a number of mechanical contriv- ances, which are controlled automatically b\- mindless animate and inanimate forces not in harmony with the author of the idea. By the division of labour with the aid of these mechanical contrivances the dailv progressive degeneration of the symbol goes on just in proportion as the machinery used is perfected. Thus the modern printer, with the assistance of the tvpc-founder, covers the page with dots, tags, serifs, ornaments, tinials. and marks of all description and in anv situation, which are not intended to den'=sh s = z ^ = ss c = ^ ckq=ckq of = of li = d 3 pg = n c = ee e = e a = ah read = reed rEad = rEd ta = twa = taa far, r = ur pii = f a =^ 00 ch = tsh queen cat kirg I'liu omission ol tin: "serils," or tlie dot. in tlu- ease of \ makes the ktlrr- ( I, h g II ' ' :'• Tlic pniljlcivi of IiitcriKitional 1-lnglish is solved h\ tlit- Orthotypc Notation, which brings the phonetic element of the language up to date; that is, to the reign of Edward \'II. It affords the printer an opportunity of taking his part in the education of his countrymen, and is the only answer liitherto offered to the (juestion how to give the additional information necessary for the child and the foreigner, without destroying European idiography and without annoying the adult Englishman who knows, or thinks he knows, how to pronounce his own language. , , u r. ( ) - A I . .. Head with a pointer and hide the letters y2i, C, 1, O, U, y) below the I'honographic Siyn- The church was a igEm rough and old SEt in ^ewEls all green or of gold You can't fail ta see how it stood Far away at the side of the wood. All the \()wel soiinils ol tin- laii;;ua,i;e .are heard and seen in tiiese lines. The principle of jjrinting reform is to associate the sound with part only of the letter, and if more than one letter is used to e.spress one sound, a part must he chosen which is common to all of them, thus the dot on the right liand denotes the gutteral sound of C» k, G. .\n ■■ Educational Print " in this form will serve as a standard for other st\les of printing. The ordinary newspaper or journal wiiose end is the dustbin, the text book which serves a passing generation and expires in the second hand bookshoii, mav well be printed in the ordinary contracted form, but words like those of the great philosoplier, Maeterlinck, classical literatme, and all books which serve the purpose of copies for imitation by tlu; ciiiid and the student, should be presented to the public in a form worthy of a scientific age. THE NEW ASTRONOMY. Ill I". SUN. I'.v l'R(M'i:SS()K A. W. r>I( KI.KTON. TlIK Al'l'ROAlHIXC. Sol.AK ICCI.I I'SIIS. I DID not intend to amplify my tentative views of the problems relating to the Sun and to Comets, as given in " The Hirth of Worlds and Systems," but the phenomenal number of naked-eye comets in 1911 and the approaching eclipses of the Sun have caused a good deal of attention to be directed to the Sun and to Comets. At the meetings of the British Astronomical .\ssociation a number of papers have been read and questions asked regarding these two subjects. Many enquiries have also been addressed to me personally, and hence I think, as the physics of the third body seem to throw much light upon most of these quest ions, that an amplification of thcsuggest ions made in mv books regarding the physics of the Sun and Comets, will be of value. I shall not at present deal w ith tlii' genesis of the Solar System, as I still believe that the Moons and Planets were captured, as I described in mv papers in 1879 and INSO. and I have made no very ex- haustive stud\- of this part of the New Astronomy during the last few years. In thus presenting a working h\pothesis relating to the ph\sics of the Sun and Comets, I wish it to be understood that these suggestions do not stand in line with the first four articles on the New .\stronomy. Most of the matter of these articles consists of deductions absolutely demonstrated to be true bv the indisputable nature of the obser\atioiial evidence that has accumulated. Thi-: Sun and its Surfack. The Sun, the ruling orb of the system of planets of which our Earth is a member, is a revolving bla;;- ing ball of fire, of such size and intensity, that, were its heat kept up by combustion, it would require to be stoked w ith six- hundred times the coalfields of the entire Earth everv minute of its existence. The great globe on w hich we live takes us some two months to travel around' it. It has a mass of some six thousand millions of millions of millions of a phott^^t aj>li inK,-n a / /(. /;,>xnl Oisi>-:i, FiciRi; 4efvj//< /«* I'IGI'RK 51. HvdroL'cn Flocculi. in the present state of our knowledge be answered, all at least are capable of receiving intelligible I'EliRrARV, 1912. KX(^\VLi:nc,i sufjgestions of solution ; suggestions that tlie diligent observers of solar phenomena may am|ilif\-, confirm or disprove. TiiK Coming Eclipsk ok thk Sin. The approaching eclipse is one that should he utilized to put manv of these suggestions to the test. These physical inductions and deductions should be used as working hypo- theses to tell what work should be done in the llying moments of that s u p r e m e astronomical event, the forthcoming; total eclipse of the Sun. l"or we have to remember that, although our Sun is a very insignificant little Sun amidst the giant orbs we call the stars, lie is hundreds of thousantls nt times the nearest star to the Marth, and hence possibly capable of sug- gesting information as to the physical constituents of the giant suns of the firmament even better than those distant orbs can tell us by their own atomic songs, as we read them in the rainbow-tinted streak, the cypher message of the wondrous story. Hence, the problem of the Sun is the supreme problem of the whole range of astro-physical re- search. How TIIK Heat ok THI-: Sin is Khi-t Up. There is very little doubt but Helmholt/'s suggestion that the Sun's heat is kept u|i l)y compression is true. The fall of molecules is thedynamical source of the Sun's heat. The surface molecules radiate heat and lose speed, and the gravi- tating power of the Sun draws them nearer to his centre, and as they fall into this new position their speed increases. It becomes so much greater than it was before, that the entire tem- perature of the Sun gets higher. Thus we have the parado.xical fact that the Sun gets hotter the more heat it loses ; that is, as long as it remains in the condition of free gas. It may be shown that a free gaseous sphere doubles its temperature when it is reduced to one half its diameter: that is, to eight times its original density. There is far more heat generated by this enormous compression than would double the temperature of the gas. but a large ratio is dissipated as radiant energy. Tlie (piantitx' of this ratio depends to some extent nil the cliaractrr of the molecules of the gas that is being acted upon. Almost certainly selective inolrrular escape is at work in ail free gaseous masses, tending to sort tlie chemical elements so as to arrange them in such a manner that the heaviest are in the interior. The elements progressively lessen in .itomic weight as we get turther from the centre. At the surface itself we get the lightest of the elements, helium, hxdro- gen, nebiiliiini. and so on. AND \'oi.c \X()i:s. taken at Cliahot Ohsetl-atofy. Solar I'niiiiinences. Look in dynamics e.xternal : surface W' Sol.AK ST()KM^ upon the 1 ■>•': a /.hotovap^i FlGL'KED.i. The Corona, as seen in the total Solar Eclipse of Ma ;is iiiu- of gaseous it wduld seem as tlloiigh, were there no (lit acting upon a mass of gas, that the lid he much more smooth and subject to much less tumult than we find on the surface of the Sun. Most of the strange behaviour of material on the solar surface seems tf) receive a solution if we look upon the Zodiacal light as a \ast meteoric append- age to the Sun, meteoric particles w hose angular velocity is too great to allow them to be absorbed with the general shrinking gaseous ma- terial that forms the Sun himself. I do not propose now to give an account of mv idea of the origin of the Sun and the solar system, other than to state that I look upon the collision that formed the Sun as almost a direct one, and that the whole of the bodies that revolve about the Sun were material that did not come into impact. They extended beyond the region of actual collision and whirled around at such a velocit\- as to be able to balance themselves in 2Sth, 1900. KNOW i.i:i)r,i-: l-'i-nurAkv. 1012. orbits. Tin- laif^i- inassis nri^^iiiatcd tin- plaiuts. llic Sflectivf action upon molecules and nxttoric matter that would produce a system somewhat similar t<> the solar SNStcm, I have already discusscscr-.-atory ■IGL'Kl-; 54. Tlie Sun, shcsvins Sun-spot Vortices rotating in opposite directions. 5-' KNowunci IKIIRUARV, 1912. Sl'N Si'OTS. I iinaj^iiu- tliat Sun spots have tluii oii};iii in similar large meteors or meteoric swarms collidiiif,' and releasing the solar energy. The spot it.self is probably the storm in the jjhotosphere that follows the actual volcanic explosion : the dark spots, which are still intensely luminous, being due to expansion. The volcanic scar pn>babl\- remains in its position on thi' Sun whilst the storm travels on the surface. The associated irregular luminous masses are jirobably regions of compression. Perhaps the uprushing hot material from the interior would also be more luminous than that which has expanded, cooled and is descending. Spots are often associated together, sometimes give l(R) much prominence to this tentative sugges- tion, ;is I have discussed the idea in some detail in "The Hirth of \\f)rlds and Systems ' in " Harper's Library of Living Thought." The Sun's LAYi=:t-_ _I ___fL _ si i_ ..,._.4\ T . _ ±T^, __ _ __ __ _: n L _$/ t - -c\ - 4-\ - - - ^^ -t n:_ _^u^».. - --/■ -\- i ^^J\ ^.^\ ^-\ - it _ -/4S- \- -Lz,\^_ i.--!^vt — ^^:_S ____/_ _:\. ''"-- /.f -^ ^s- /-^-A - ^v U -V^ - -I V___ ^'>_ _. ....,^.i:izst4£wi\y/tl;:-^^i_. \^_-iJ^^a^4%^^ ? -^--. - ....;-- ?S^ 4.^^- \/ts, V i ^ I ..: _ __/l _:\^j^tv ,__ ! /__- S-W- -^-^ " "1 ' .7^_iZv^.- -^-±r5- J- A ^--_/,-__ ^__^E^rf ^,. -^ ii2..^.^y^- 1_ -* _^^ j_ ___^ -"4vj: 1 \^ .... 4 _^.'^:__ _ ^— ^ I ^^^ /"" ,^ ^-v, ^ s^J MEDICINES: ANCIENT AND MODERN. By ol.IXI.Iv C. \l. DWls. D.Sc. Lecturer in Matcrut Mcdicii in the Cnivcraity of llrislol. FlGlKK 5(). Aimilcts of tilt: two fii Thk past fiftv years has witnessed a vur\- ^reat activity anidiif^ investigators in e\cry l)ranch of science, and the results of countless workers have been made use of for \'arious purposes; it is highly probable that no art has gained such \aluable knowledge through e.\i)eri mental research as that of medicine, which has been raised from gross empiricism to the proud position it now occupies. This satis- factory state of things has been brought about not only by direct chemical observations made by medi- cal practitioners, but also b\ the chemist. ph\-siologist, and bacteriol- ogist in their respective laboratories. In early Egyptian times the practice of medicine lay in the hands of the priests, and was a sacred art sur- rounded by mysticism and superstition: it was then customary to use amulets (some of which were worn during life, and buried with the dead) and other charms as preventives of various forms of disease — fore- runners of a scientific scheme of prophylactic medicine. (I-'igures 56-58). The preparations for internal use up to the end of the fifteenth century consisted very largely of vegetable sub- stances, and were chiefly characterized by the vast number of the ingredients which com- posed them ; towards the end of that century Basil \alentine at- tempted to employ chemical substances in medicine, and actually recommended the use of antimonv for fever /^^ 1 • , " J ,1 Figure 3/. (Malaria), and other diseases which we now let Amulets. term protozoic. The use of antimony has lately been recommended by Phmmcr ( 1906) . Shortly- after, Paracelsus boldly stated that the object of the chemist was to prepare medicine, and not make gold — which was an alchemistic idea. One of tile first pharmacopoeias sanctioned by civil government was published at Xurnberg in 1545; it was largeK- based on the work of Galen, and some of the j)reparations therein contained are still in use. The first edition of the Pharmacopoeia Londinensis (16hS), mentions one item. "Cranium humanum violente morte extinctum." which is sufficient to demonstrate that the apothecary's art was then surrounded by a veil of superstition : in the same edition was included tlu- Theriaca of Mithridates which contained about two hundred and fiftv ingredients. .\ most instructive and interesting contemi)orary work is ■■ Burton's .Anatomy of .Melancholy." which in addition to mentioning all sorts of oils, liniments, plasters, and cerates, also sets forth the virtues of " sacks, bags, odoraments, and posies." from this period, right down to comparativcl}' recent times, an examination of medical works shows very clearly the abso- lutelv empirical and unsN'stematic way in which medicines were compounded and ad- ministered: this is readih' accounted for when we remember in the first place that the knowledge of the con- stituents of \egetable ilrugs was extremely \ague and unsatis- factory; secondly, that reliable information re- garding tile action of drugs and their fate w ithin the organism was almost entirely lacking, and last, but by no means least, the un- derlying cause of disease was seldom known. It is due to researches in these directions that our knowledge of the constitution of drugs and their physiological action has been progressing with a remarkable rapidity during late years. In the chemical laboratorv it has been show ii that, Figure 58. Papyrus Sceptre Aiiuilets. KN(n\i.i;i)(-i I EHRl!AKY, 1912. / 3.- -Aconiti' Kool. -Calabar Hcans. -Cinchona Hark. iiiiiliT siiitalilc iiiMtiiU'iil. iKitiirai products, siirli as loaves, routs ami l)arks may Ik- made to yield delinitc ciicmifal compomuls. amonf^st wliirli arc tiic alkaloids and jL^hicosidcs : tlicsc lia\c in many cases Ill-en \ery fully investi- fjated both from tlic |K)int of view of tlieir chemical structure and their action on living orjjianisms. l-'if^iu'e 59 shows six natural jjfoducts from which powerful alkaloids are extracted : Aconite root and Calabar beans (obtained from West Coast of Africa) re- spectively contain aconitine and ph\sostigmine. (luininc exists in Cinchona bark, cocaine in Coca leaves, ergotiniiic in Mrgot, and Nux- \'omica gives rise to the well- known substance stryrhninc. The vast strides in organic chemistry have also enabled the chemist to synthesise large numbers of compounds possess- ing a known structure and a known action — which action can frequentl}' be modified by a modihcation of structure : these synthetic compounds have, after investigation, been classified according to their action as antipyrctirs antiseptics, diuretics. h\-pnotics, and so on At the i)resent time, there- fore, instead of administering mi.. to his patient large quantities of indefinite and uncertain preparations containing numer- ous ingredients which may lie chemically or physiologically antagonistic to each otlur. the jihysician is enabled to select some definite compound regarding which he knows both the chemical constitution and the physiological action : by sub.sequent observation of tin- patient he can ascertain whether the drug is acting in a satisfactory manner, and. if not. administer one of a different chemical constitution: but under the old conditions of "polyphar- mac\' " it was a \irtual impossi- bility to attribute the harmful or ., ^^^ „. beneficial action of a preijar- ation to any special ingredient. As an illustration of the possibility of modifying the action of a chemical compound, the case of aniline and certain of its derivatives ma\- be taken. Aniline, which has verv marked plusiological •^f* 4. — Coca Leaves. .i.— Krgot. 6. — Nnx Vomica Seeds. a< lions, owes its ac tivity largcl\- to the |>resence of the benzene nucleus, and the view ma\ be held that the "amino" group - N H,j, ' rves as an "anchoring group," I lid thus brings the molecule into contact with the proto- plasm. It is far too to.xic for satisfactory application as a en/anilide are quite useless, since the former is far too readih acted upon by reagents, and the latter under similar conditions is not appreciabl}' broken down into reactive pro- ducts. It has been shown by numerous workers that the stereo- configuration of an organic com|)(jund, i.e., the spatial arrangement of the component atoms and grou|)s may exert a profound infiuence on its chemical properties: thus the '■ ortho " and " para " toluidines (which differ only in the space relationship between the two substituent groups in the benzene ring), behave quite differently towards reagents, the former compound being the less reactive of the two; corresponding with this difference in chemical properties, the to.xicity of the "para" compound is approximatelv twice as great as that of the "ortho" ") o :> FlGUKli 61. Trypanosoines in Blood. Photographed from an excellent drawing made froiri an actual specimen. certain alkaloids, ether, and chloroform, found a place in the first British Pharmacopoeia, and the last edition contains details regarding a number of synthetic com[)ounds, among which may be men- tioned .\cetanilide. Phenazone, Salol, and Sulphonal. .\l)art from the great advances in Pharmacology- brought about by the researches of chemists and ph\siologists, there has been a distinctl\- forward . movement on the part of pharmacists to place within the reach of medical practitioners galenical preparations of undoubted quality, strength and elegance, and this advance is largely due to the British Pharmaceutical Conference. In the first edition of the British Pharmaco- poeia, previously referred to, man\- tests are given for impurities in inor- ganic chemicals, but very few standards are set for drugs of organic origin ; in the second edition there is a distinct im- provement in this direction, which is main- tained in a .striking manner in the latest edition, in which directions are given for the accurate standardization of a consider- able number of tinctures and extracts — such as those ^•^^^^ derivative. .\n importantexamplc of this phenomenon of nux-vomica, opium, belladonna and ipecacuanha, will be dealt with subsecjuentl\-. wlien the treatment of sleei)ing sickness is discussed. This increasing use of isolated active principles and definite chemical compounds in place of pre- parations of uncertain strength and indefinite action, is well demonstrated b\- a comparative study of the three editions of the British Pharmacopoeia, when it will be noticed that many of the old-fashioned con- coctions are being gradually rei)laced by those which are rational and scientific in their composition. As an example we ma\' take two classes of preparation typical of the old conditions of pharmacy, con- fections (electuaries) and decoctions — the former are semi-solid medicaments consisting of various drugs, chiefly of vegetable origin, mixed together with sweetening agents, such as honey, and the latter arc made by boiling barks, roots, and so on, with water. The 1864 Pharmacoi)oeia includes seven confec- tions and thirteen decoctions; the 1885 edition, a much larger work, includes eight confections and thirteen decoctions, and the latest edition, published in 1895, mentions onl}- four confections and three decoctions. In place of such as these there has been an introduction of increasing numbers of definite chemical substances into official pharma- ceutical works; several such preparations, c.t;.. which contain as their active principles poisonous alkaloids. In one special case — nux-vomica — the pre[)arations are adjusted to contain a definite percentage of strychnine instead of total alkaloids, since it has been found that this alkaloid is far more toxic and active than those with which it is associated. In cases where no official standard is set, various workers have described satisfactor\- methods for obtaining uniform standards, which are adopted by the leading manufacturing chemists. While methods of chemical standardization are very desirable, yet, in some instances, they are not quite satisfactory, and in such cases physiological methods are used : this applies more especially to those preparations derived from digitalis, ergot, and strophanthas, where an inactive drug might be responsible for most serious results. .\11 this valuable information with regard to the structure and pharmacology of drugs would be of little use in practical medicine but for the great accumulation of knowledge regarding the cause of man\- diseases. In this direction Lord Lister, Pasteur and Koch have done pioneer work in proving conclusively that definite diseases are frequently associated with definite micro-organisms termed bacteria or bacilli, which must be exterminated to elTect a cure. It 5.S KNC)\vij;i)r,i:. I■"l:lll<|■\R^, 1912. has also been shown tliat ixrlaiii diseases are caused by a larger species of micro-organism known as jiroto/oa whicl) find tlieir way liy various means into the blood of hunian beings or animals and bring about pathological conditions. Drugs which act by destroying such micro- organisms are known as " specilics." and to this class belong i|uinine, arsenic, antimony, and mercury. ( Uiinine, the specific for malarial fever, was introduced to European ])harmaceutics soon after the discovery of Peru, and has been gcnerallv recommended since the successful treatment of the Countess Cinchon (1640), hence the name, " Cinchona," of the tree from which the drug is extracted. Of very great medical importance is arsenic, especially those organic compounds which contain this element. An arsenic j compound known as "Atoxyi" lias i)een | successfully used in the treatment of sleeping sickness. It is chemically known as Para-amino-phenyl-arsenic acid, and is represented by the constitutional formula. (See Figure 62.) The isomeric " ortho " compound has I-iclk no effect on the slee[iing sickness parasites (Trypanosomes) ; these are shown in I'igure 61, in which they are seen in the form of elongated flagellated structures between red and ^ ,, white blood cor|)Uscles. mi The elaborate investigations of I'hrlich, Bertheim, Nierenstein and others on the action of atoxvl have led to the discovery of SaKarsan. commonly know II as " 606," which it is hoped ma\' I prove a specific for s\|)hilis. Mercury and antimony have a similar "specific" action, and the effects of ■■^"■•i some of the aniline dyes are ver\- interesting, one of which, .Methy- __-j^-^^ lene Blue, is used in the treatment ""-- — OH "f Malaria, in cases where the protozoa have been rcfractorv to quinme. It is to be li()i)etl that as scien- tilic research proceeds other specifics will lie introduced into the practice of medicine. / M\ thanks are due to Mr. J. Ouick. curator of the Bristol .Art Galler\\ for [ler- mission to photograph the amulets which K bZ. are in his care. II". ASTkOXO.MU'.AL S()Cli:r\' Ol' n.ARCELOX.A. A GENMROl S DONOK. I-ORTHCOMING LLXAK i:\Hir.ITION. MM I. receiving the Koyal favour a year af;o tliis Society li.is considerably increased in numbers. The roll now contains four hundred names, and the Society is entering upon its second winter season with very rosy prospects. One of the objects of the Society, upon which special stress was laid at its foundation in January, 1910, was the provision of a public observatory where members might meet on fine evenings to study celestial phenomena, and to discuss points of astro- nomical interest. This, indeed, is the primary object of most societies of this nature, but it is seldom that it is realised. In the case of the Barcelona Society, as a matter of fact. although a reserve fund was accumulating with considerable rapidity, it w-as felt that it would be a very long time before the Society could acquire a suitable observatory. It is pleasant to record, however, that the primary object of the promoters has been realised very imexpectedly, and without cost to the Society, in such a manner that within the next few weeks the members will be in absolute possession of a well-equipped observatory. Seftor Rafael Pat.xot y Jubert. one of Spain's illustrious men of science, and a fomidation membi r of the Society, has been so greatly impressed by the valu.ible work which is being carried on that he has offered to present his observa- tory and instnmients to the Society, and, needless to say, the ofler has been eagerly accepted. This establishment. "The Observatori Catala," is situated at San Feliu de Gui.\ols. in the province of (ierona, and in importance stands next to the observatories of Madrid and San Fernando. It has accom- plished much valuable astrophysical work under the director- ship of its owner during the past ten years, chiefly in the direction of the measurement of multiple stars. The whole establishment will be removed immediately to Barcelona, where it will be re-erected on the roof of one of the public buildings in a jiosition easy of access to all members of the Society. The dome, which is constructed of steel, has an internal diameter of seventeen feet, and was made by Messrs. (.jilon, of Paris. It covers a fine double e(|uatorial by Mailhat. visual and photographic, with apertures of eight and three-quarter inches, and focal lengths of ten feet and seven feet nine inches respectively. A complete set of accessories of precision is included in the gift, spectroscope, micrometer, camera, electric pendulum, and azinuithal theodolite. .Annexed to the observa- tory in its new position will be a room for meetings of the Society, library, photographic laboiatory. and so on. The Society realises that the best way to thank so generous a donor as Senor Patxot is to prove to him that his gift is appreciated to the fullest extent, and therefore one may con- fidently look for great things from Barcelona in the early future. One cannot speak too highly of disinterested generosity such as this, and whilst congratulating the Society on its good luck, one must also congratulate the donor, not only on his beneficence, but on his wisdom in choosing so deserving a body upon which to exercise his generosity. The value of the gift must not be expressed in terms of £ s. d., but nmst be reckoned by the amount of pleasure and instruction which it will aflbrd to the thousands of people who will be privileged to use the instruments henceforward. Preparations for the public Lunar Exhibition which will be held in Barcelona in Nlay, 1912, are being pushed forward rapidly, and .ilready many promises of assistance have been received from all parts of the world. The following gentlemen have accepted invitations to serve upon the honorary Executive Conunittee: — Messrs. Flammarion, Pickering, Frost. Campbell, Aitken. Hale. Ritchey, .'\ntoniadi. Baillaud. Piiisieux. tioodacre. CeruUi, Bolton. Diseilligny, de .-\/carate, R. P. Cirera, Ricart y Giralf, Stroobant. and Weinek. The success of the Exhibi- Febri-ary. 1912. KN"0\VLi:i)CiE. 59 tion. therefore, seems assured. Among other e.xbibits already amiounced. the Lick Observatory promises to send a set of twenty sheets of the great photographic Lunar Atlas obtained by means of thi- thirty-six inch refractor between USS9 and liS'J5. together with a collection of transparencies on a large scale specially intended for exhibition in various countries. M. Fuisieux has intimated that the I'aris Observatory will be pleased to exhibit a copy of the Lunar .\tlas which was the culminating point in the work of the late M. Loewy. and which represents one of the greatest triumphs of modern .istrononiical photography. On behalf of the Lunar Section of the Hritish Astronomical .Associa- tion, Mr. t.oodacre will exhibit the superb collection of drawings recently shown at the Coronation Exhibition. The Barcelona exhibition will be held in the University buildings, under the honorary presidency of the Rector, Baron de Bonet. The Executive Council of the Society invite the co-operation of selenographers of all classes in order to make this exhibition, the first of its kind, a great success, and with this end in view, the Secretary would be pleased to receive promises of assistance from any readers who may be able to contribute exhibits, no matter how modest, bearing on the subject. .\ll comnuniications should be addressed to Senor Don Salvador Kaurich. Callo (Iran Via Diagonal, 462, 2". B.ucclona. Spain. WM. I'ORTHOUSE. SOL.AK Dl.S ri RD.WCKS DL'RIXC, 1 )i:( 1:M IIKR, 191 1. IJv FRANK C. DENNETT. .\ I'ARTHKR falling off in solar activity has to be recorded during December. Continuous observation has been hindered both by the low altitude of the Sun and the poor atmospheric conditions. On thirteen days (4, 5, 6, 7, S. 9, IL 12, 16. 17, 25, 27 and 301 the disc appeared free from disturbance, and faculae only seen on three (3, 14, and 19). .At noon on December 1st the Central Meridian was 205° 21'. from longitude 258 to 269'. Again on the 24th there was a bright patch south of Xo. 41, in latitude estimated as being between 30' and 40 '. The only observers able to make efiective telescopic observations were Messrs. McHarg, Buss, and Dennett. Our second diagram shows the positions of the whole forty- seven spot disturbances seen during the year 1911, six of DAY OF l)i:CKM15ER, 191 i. 13 ^ 1,; '? ? '1- 1? ' ? 7 « \ ?L^i»_^_i ', ?s J|7 ^'' 2,^ 24 ?3 22 ? 7f> '? P T s id Id Ki 4 :.. s w !0- Frf Q :- ■^w. of N FCD^L S m 20' 30' «' 50 95 W 10' 120' 150' W !»' I6(f W 190' 200' 210' 220' 23flr 2rf 250' 260' 27J' 280' 29Cf XO' 310' 320' 330" 5*0' 350' 3«0' No. 41. — Apparently the only spot disturbance during the month. On the 20th there was a small spot found in the southern spot-zone, the leader of a trail of pores only 22,000 miles in length. When next seen, on the 23rd and 24th, it was as a solitary penumbraless spotlet with a ragged border, and which was quite gone by the following day. The only other disturbances seen were faculic. On the 3rd such a disturbance was seen within the south-western limb. which must have been situated a little south-east of that shown on the monthly diagram on longitude 260°. On the 14th a small knot near the western limb, in longitude 102° marked the place where No. 39 had disappeared. On the 19th an extensive district streaked with faculae, around the site of No. 40. was visible within the eastern limb, reaching which were rather secondary or attendant outbreaks. Thirty- two were in southern latitudes, and fifteen in northern. The distribution of the disturbances is a striking feature. In the southern zone, between J5° and 1.30° there are fifteen out- breaks. Between 1 66° and 203 ' twelve more, with five between 241- and 263°. whilst situated by itself is No. 41, between 287° and 290 . Thus it will be seen that from 1.50° to 166', 203° to 24I%263° to 287% and 290' to35° the surface has apparently been quite free from spots. In the northern zone three small disturbances have occurred between 6° and 38°, seven between 103' and 170°, and five between 213° and 258°. The regions between 3S° and 103'. 170= and 213°, also 258° and 6° in the northern hemisphere, have also thus been free from outbreak as well. DISTRIBLTIOX OF SPOT-DISTURBANCES, 191 1. s 3d 1 s ■'* •-.. , B' '»» ^ -.„ , . o'V > ■; - '..» "V 30' •• vf ii-o. N. « irf 20" ilS W 50' 60' Ttf bJ Stf KKf IKf I2tf Wf Ktf ISIf teJ \JS 180" IStf M 20' ZlfS lilS ITS ZM J90' JOO" SKT 320' 3J(f Mf 550' 360" Tfll- l-ACI' ()!• Till- SK\- l-()U MARCH \W A. (. I>. I K( »MMI.I.IN. l;..\.. D.s... l.K..\.>. 1 1 -OM. Mercury. Vciiiu. Mars, Jupiter. Saturn. Unuios. Neptune. \ Dec K.A. Dec. R.A. Utc. R.A. Dec. R.A. Dec. R.A. Dec R.A. Dec. R.A. Ite;. No..n. h. III. h. m. « h. III. , h. m. „ li. m. 0 li. ni. h. m. b. ni. h. m. March I .. ■=.' iS; S.7-ri TJ 47 "^ S. 9-7 ao 43-4 S..8-4 21 8-4 i6"9 4 4f9 N.744 16 50-7 .S.2r7 2 53'4 N'.I4'4 2o l6-2 S.Jo-3 7 3'- - „ n r : : : I S. 1.1 1 ■..■. 5-6 4 5J':: 24-0 16 52-5 21-8 2 55" M'^ 2.. 17-1 20-J 7 3I-- .• 1 1 I S.i-i !l 33-9 15-3 5 '9 »4'8 16 540 21-8 2 56'7 M'7 v> i8-i 201 7 30-., ,. ID . N.j-6 " 57'i 134 5 -S'S 250 16 553 21-8 2 58-5 14-8 20 19-0 JO-l 7 VjT vi 4 7'9 5 25-0 25-2 16 56-1 21-8 3 05 '5'o .» I. . r. .;, -' ' ., "'■' " 44 ■» 9J 5 36-5 25-3 16 56-7 21-8 3 2-6 15-I 20 20'S 2.)1 - ■ , N.4-. .1 J47 N- i-u i 4'-| N..3-7 33 7 '.3 S- 7'' S 48-2 N.2S-3 16 s7'o ■S.21'9 3 4'7 N-"S'3 20 21-2 .S.20 . Table 6. Dale. Sun. Moon. Ma i>. Jupiter. Saturn. | P B L ' P 1! L 1 '■ 1; •^l Lj T, Tj P B i Greenwich Noon. 0 0 0 0 0 0 0 h in , ^ ^ J, Q h m h m 0 0 ' March i -2.7 S.7-2 86-8 + i6-5 -32-7 S.7-4 204-7 10 38 c 824 •78 +(>•■! S.2-9 '35 "4 97 S 8 17 III 7 >4« -0-8 S.2I-3 22-9 7-3 21 "o + 19-8 31-8 6-4 ■56 "9 1 15 III 83 '2 "75 6-3 2-9 204-9 128-9 6 23 /« 8 26/// 08 21-4 ., II 23-9 7 2 3>5'' + 0-2 310 5-4 109-1 4 32 '" 84-2 ■72 6-2 2-9 274 '4 160-3 2 20 ^ 7 34"' 09 21-5 248 71 2402 -J95 30-0 42 7 48 m 8^-2 ■69 29 344-0 191-7 2 35 III 4 38' 0-9 21-7 25-5 7-0 .83-3 -18-7 290 3-1 ■3 '.3 II 5 /" 86-2 •65 5-0 2-9 53 '7 223-3 8 22»- 5 50"» i-o 21-8 ■■7 "3 + S-o 27-8 2-0 .-»5'3 2 23 f 87-2 •62 5 '9 2-9 123-5 254 9 8 37 ,11 » 53' I -J 22-0 Sl'4 + 21-8 -26-7 S.o-8 277 'i 5 40'- 88-3 ■59 + 5-9 S.2-9 193-3 286-5 4 .33' 4 5 '" -11 S.22-I jiiiiig fcspectivcl) Table 7. (;rei--iiuicli Civil Time is used througlioul. the day commencing III. e denote morning and at midnight. P is the position angle of tin; Inidy's North Pole, measured eastward from the North point of tlie disc. B, L are the Heliographical or Phinetographical latitude and longitude of the centre of the disc. In the case of Jupiter there are two systems of longitude, one for the Equator the other for the Temperate /ones. T denotes the time of passage of the zero mcMidian across the centre of the disc. Intermediate passages for Jupiter may be found by applyhig nuiltiples of 9'' SOA™, 9'' 55A'" for the two systems; for Mars apply multiples of S-T" 39". O. (| for i\Iars are the position angle and amount of the greatest defect of illumination. The Sun crosses the Equator and Spring commences at lli''<;on March 20th. Its semi-diameter diminishes during the month from 16' 10" to 16' 2". At Greenwich it rises at 6" 48"". sets at 5" 37"" on Marcli 1st; rises at a" 40'". sets at e*" 29"" on March 31st. 27, 7° S. ; .April 3. 5 W. The letter indicates the direction on the limb of the region brought into view. E. \V. are towards Mare Hnniorum and Mare Crisium respectively. Mercury is too near the Sua to be seen at the beginning of the month, but is well placed as an evening star at the end D.1IL-. Star's Name. Magnitudes. Disappearance. Reappearance. Mean Time. Angle from N. to E. Mean Time. Angle from N. to E. I9I2. h m h in Mar. 3 1 Leonis 5'3 4. 2 III SS" 4.50 III 334° ,. 4 13 Virginis 5 9 7-46 f 149 S.37' ., 4 1) Virginis 4-0 S. 7'- 1 93 9. o<- iH ,, b B.\C 4445 7-" — 1 — 2.24 III 31S 1 „ 9 B.-\C 5220 6-7 — 1 — 2. 0 III 311 „ 9 BAC 5253 5 4 4.21 III 123 5.41 III 1 2S2 „ 9 B.JtC 52S6 5 '4 7.17 »' >05 S.32 III 2S2 „ 10 B.AC 5595 6-9 — — 2.4S III 16 ,. 22 5 Arielis 4-6 9.24 <- 116 10. 5. <2 42 0 13 ,, 2S 4 0 3'2 .. <3 41 0 2« .. 29 43 > 0 2 ., '4 43 0 12 „ 30 432 CJ I ., 'S 315 0 ., 31 i' p 2 ...0 32 0 14 1 Phenomena visible at Greenwich: — 2* 4'' 0'" I. Sli. I. 5" 15'" I. Tr. I.. 6" 12"" I. Sh. E. ; 3" 4" 17"' III. Oc. 1). 4" 47"" I. Oc. R. 6'" 13'" III. Oc. K; 4"' 4" 55"' II. Sh. I : 6'' 4" IS'" II. Oc. R; g*" 5" 53" I. Sh. I; lO*" 3" 14'" 27' I. Kc. I), 3" 16" 57" III. Ec. D, 4" 58'" 57' III. Ec. R; ,,,1 ^h 3^m J g)^ g^ 3h ^gm J -j-j. g . J3d jh ^(jm j g» II. Ec. D; 15'' 1" 58"" II. Tr. E; 17" 5*' 7" 51' I. Ec. 1): IS'' 2" 14'" I. Sh. I, 3" 29"^ I. Tr. I, 4" 27"" I. Sh. I-., 5" 42'" I. Tr. E.; ig"* i^ 1"" I. Oc. K. : 20'' 4" 19"' 52- II. Ec. n.: 21'' l*" 52"' III. Tr. I.. S^ 47'" III. Tr. E. : 22'' l" 51'" II. Tr. I.. 2^ 1"' II. Sh. E., 4" 29" II. Tr. E. : 25" 4" 7™ I Sh. I.. 5" 19'" I. Tr. I. ; 26" l" 29" 37" I. Ec. I)., 4" 52"" I. Oc. R. : 27" 0" 48"' I. Sh. E., 2" 0" I. Tr. E. : 28" O" 51" III. Sh. I.. 2'' 50'" III. Sh. E., 5" 38" III. Tr. I.; 29" l" 57"' II. Sh. 1.. 4" 20'" II. Tr. I.. 4" 36" II. Sh. E. ; 31" l" 5" 11. Oc. K. .Ml these phenomena are in the morning hours. .Attention is drawn to the almost simultaneous eclipses of 1. and III. on tlic loth. The eclipses occur high left of the disc in the inverted image, taking the direction of the belts as horizontal. Satlkn isan evening star,dra\ving near the Sun. Equatorial semi-diameter 8i"; major axis of ring 39J", minor 14A". The times of some Eastern elongations of the Satellites are given ; intermediate ones are found bv applving multiples of l" 21'" for Tethys. 2'' 1 x" f..r ni.-ne. Tethys J" 4" m, 8" 8" c. 14'' iiooii^ 18" 7'' III ; Dione Z' S'' e, 8'' 8" m, 13" 7" c. 16" 1" c ; Rhea 4" 4'' m, 8" 5" e. 1 3" 5'' m. For Titan and lapetus E., W.. stand for E. and W. Elongations: I.S. for Inferior and Superior Coniunc- w .^ t. ... .. .... 1 >j. 1 uan ana lapeius c., v\ ., siana lor 1-,. and W. Elongations: I.S. for Inferior and Superior Conjunc- tions. Titan 5" 7" m 1, 9"4''m \V, 13"2''m S. 17" 6'' hi E; lapetus 16''8'';jj E. Uranus is a morning star, but very badly placed. Semi- diameter If. NiiPTLJ.xiv is well placed as an evening star ; semi-diameter 1 1". A map of its course was given in " KNOWi.iiDGi; " for December last. CoMliTS. — Elements of Comet L 1911, discovered by M. Scliauniasse at Nice, im November 30th. T =' 1912, Feb. 5-34, G.M.T. u - 109° 7'-6 Si = 115° 12'- 1 ( = 20° 29' -4 log (J ^ 0-06822 Ephemeris for Paris midnight : — R. .\. S. Dec. ! K..A. S. Dec. h. m. s. h. III. s. 1 Feb. 2 17 37 3' 8 21 March 5 19 40 30 11 II ' „ 6 '7 54 23 8 55 .. 9 19 53 42 II 19 10 iS 10 S3 9 25 .. '3 20 6 22 II 25 .. 14 iS 26 59 9 S' .. 17 20 iS 30 II 29 .. uS iS 42 39 10 14 ., 21 20 30 9 i: 32 ,, 22 'S 37 53 10 ii " 25 20 41 ij " 34 ., 26 19 12 36 10 48 „ 29 20 5" 53 " 35 .March I 19 26 50 II I The comet is brightest at the end of January, but is then of only the 10th magnitude. It is a morning .star. Mi:teoks. — The following list of showers is due to Mr. W. F. Denning. Radiant, R.A. 1 Dec. Mar. I -4 .. 166° -f 4° Slow, bright. ,. 14 - ., IS ... .. 24 250 + 54 316 -t- 76 161 -4^ sS Swifi. Slow, bright. Swift. 229 + 32 Swift, .small. Mar. to May 263 - f)2 Uallier swid. Every Third Minmmum of Ai.goi. (Period 2" 20*" 46'") March l" TO" 16" m, 10'' O" 43" ;;;. 18'' 3" 9" e. 27'' .5" 36"/i(. DOUULIi Stars.— The limits of R.A. are 9'' to II". Star. Right Ascension. Declination. Magnitudes. Angle. X. t.i K. Distance. Colours, etc. N 2; -3 ; ". 7 200 7 White. 38 Lyncis 9 i; N 37 -2 , 4. 7 236 While, blue. 39 Lyncis 9 16 .\ 49 •<> i 6. 8 320 0 \\ hite, blue. 21 Ursae Majoris 9 I'l N >4 -4 7. S 313 5 -J White, blue. 23 Ursae Majoris 9 24 N 03 5 4. 9 270 22 Greenish-white, -Ash. u Leonis 0 24 ^ 9 "5 6. 7 127 I Yellow. Groomb 1569 q ?6 N 39 4 7, 8 29.. 3 \ellow, blue. 7 Leonis 10 1 5 X 20 ■ ) 2, 3 liS 4 Golden. Struve 1430 10 25 N 21 -3 S, S lie Ij White. 49 Leonis 10 30 N Q 1 6. 9 156 2 While, blue. 35 Sextant!-. . 10 3q N 5 -2 6, 7 Z40 6 S'ellow, blue. Lalande 20799 ■o 43 S 14 -s 6, 7 7. S 17 19S 6q I 6i 1 Triple. 54 Leonis 10 51 N 25 -2 5- 7 107 6.i Greenish-while, blue. knowli-.dgh;. Februakv, 191 ; Clusters and Nebulae. Name. R.A. I )ir. Ucinarks. Qh lom N 5i"-4 I.iirdc oval, bri|;l)l iicl)ul.-\wilhniicl(.us. w ;''. 57 ,l 39 \ 17 1 Curious field nearly Heviiiil of slats. w- 7S 9 42 N 72 ■- UtiKliI nel.iila. M. Si. S2 0 49 \ (.() -6 Two bright nebular \ apart. W '• "fj 10 I ■^ 7 i Kairly bright nebula. W '■ J. 4 10 10 N J 11 Two faint nebulae. I^IV 27 10 21 S iS -2 liright planetary nebula. Wi- .S6 10 23 X 29 'o Bright oblong nebula: 1 1 mag. nucleus. tt I. 17. 1"^ .0 , . \ ,.; -1 Two faint nebulae, some others near. .ippcaiancc will probably be that of a few beads of sunlight at the Moon's edge, not of a continuous ring. Tm-: Soi..\K Eci.iisL 01 .Vfuii, 17. — It will probabI\- be convenient for those who propose to ^o to the central line in this eclipse to have accurate information siillicifntly lon.i; beforehand to make their arrangements. The following positions are based on a combination cif the American Ephemeris with the Nautical .Almanac, going ,' of the way from the former to the latter. (The reasons for this course are given in the Journal of the H-.A.A. for Decetnber.) T, A denote the probable durations of totality or annularity. It should be noted that the phrase " annularity " is really not suitable for l-'rance, :is the Ixingitude. I.ntiludc. Duratiiin. 7 5 ■ -3 A 1 4.S -3 I-" 4S 45 -2 2 -6 A 4 20 -2 50 12-4 4 'O .\ 7 S 9 5' 39 0 5-6 A 10 17 y 53 4 '6 7 -6 A 13 5' -5 I-- 54 2S -5 N 9 -9 A The track enters Portugal at Ovar, which was also on the central line in 1900, when it was occupied by the Astronomer- Royal, and many other English Astronomers. It passes eighteen miles due east of Oporto, enters Spain near the village of V'erin, in Orense, passes seven miles due east of X'illafranca, in Leon, two miles east of Oviedo, and leaves the peninsula some seven miles east of Gijon. According to the above figures it wiil cease to be total while traversing the Bay of Kiscay. It enters France six miles S.E. of Les Sables d'Olonnc. in Vendee, passing fourteen miles south of Angers, nineteen south of Le Mans (noted for aeroplane experiments), through St. Germain en Lave, in the western environs of Paris, very near N'amin- in Belgium, and onward into Germany and Russia. Details for the partial eclipse in the British Isles will l)e given next month. CORRESPONDENCE. SWEK PINGS. I'd the Eilitors of " Knowledgi;." Sirs, — Mr. Enock ' evidently has misread Westwood's "Introduction to the Modern Classification of Insects," or he could not have written of Elcnchus tcniticurnis Teinpleton, of which but one example had hitherto been recorded over fifty years ago. In the text Wcstwood gives no author's name, but in the synopsis bound up at the end of the volinne he gives it correctly Elcnchus tcniciconiis K. .Moreover, in the few pages in which he deals with Elcnclius and the other genera in the order Strcpsiptern, he refers to specimens of this insect having been taken by Stephens, Dale. Haliday and Walker, in addition to that by Mr. Templeton (which he (jueries as belonging to another species W'alkeri Curtis), and although he does not expressly mention the insect, he was obviously aware of the mutilated specimen on which Kirby based his description in 1811. There are thus no less than six separate and distinct captures of this species referred to in the volume consulted by Mr. Enock. There has been considerable hesitation in admitting the claims of E. Walkeri Curtis to rank as a distinctive species. Mr. S. L.Saunders,in his monograph of ihi'Sf ylopidnc (Trans. Ent. Soc, 1S72), queried it, but very properly divided the records between the two species described, and the framers of our lists, with one accord, have refused to admit more th.in one distinct species, E. tennicornis K. In the latest monograph of the Strcpsiplcra, written by W. 1). Pierce and published this year in the "Genera Inscctoriini." the author elevates E. Watlicri Curtis to specific r,ink. Me ,ilso adds the impor- tant fact that " /:. tennicornis K. is known to be parasitic on leaf-hoppers, prob.ibly of the genus I.iburnia." Mr. Enock is to be congratulated on his success after so many years' search, and it may be that with this hint he will be successful in elucidating still more of the life history of these wonderful, minute p.arasites. B.VKNSLEV. E. G. B. ruE \i:l()City oi" light. To the Editors of " KNOWLEDGE." SiKS. — In the October ninnber of ''Knowledge "you kindly published a letter from me suggesting that the Velocity of Light, should be re-calculated from observations to be made at dilTerent heights above the earth's surface, so as to see what retardation, if any, is caused in the velocity of light by the earth's atmosphere. My sug.gestion was founded on the fact that we can see a flash of lightning, which apparently usually passes from the thunder cloud to the earth; and because the human eye is not capable of seeing juiything that passes across its vision in less than about one-tenth of a second, it seems to me that a flash of lightning takes more than one-tenth of a second to pass from cloud to earth. .As a thunder-cloud is seldom at a greater height than two miles above the earth, does not the flash of lightning take at least one-tenth of a second to travel this distance r Mr. Charles E. Benham in the December number of ■■ Knowledge," page 471, suggests that I was trying to hoax your readers. Nothing was further from my thoughts, and I will try to explain myself more thoroughly. The fil.unent of an electric light causes obstruction to the current of electricity flowing from the generating station, and the obstruction is so great that heat is generated and the In an .irticlu entitled " Sweepings," Knowledgi;, Volume xxxiv., page 400, Kigurc J w.ts by an accident l.-ibelled ■fem.ale," insto.iil of male, after Mr. ICnock b.id p.issed liis proofs. Ki>s. FEBRI'AUV, l^ Aj^.cit- At^;i.,\r 15' ^3" ll' 50' i' 4 1 Ji 45' 10 IS S 13' ' 50' I'Ziia-i' Ai il 1 0 \i5' £' \i td i' 3i>' '^S S' It' 180' \h' (^ if^ <&• Si.' \i' 39 D" uul r respectively. Bisect A D in L, and .\ L in M. and \! P, and produce tlicm to meet arc 1! C in J |)ectively. Join J .A and K A. Then the angle B A C is divided into the three equal angles, BAJ. JAK, KAC. It is obvious that the smaller the angle B A C, the more nearly do A J 1 and A K coincide with A N and A 1' ^ Kspcclixely, and thus approximate to ^^ the solution by .Method 1. In order to ascertain the degree of u accuracy of the three methods — that of Mr. Binglej' and the two described above — I have examined each of them an.dvticallv. If 2a be the angle B AC, and 2ff be the middle (J A K) of the thiie component angles, then By the Bingley method — cot a -f- -2 cosec a = cot f^— J cosec /i. I5y Method I— cot a -f- 2 cosec o = cot 1^. By Method II— cot a + j cosec o = cot (3 — I cosec /^. If each of these equations be solved for different values of o, the error inherent in each method can be deter- mined. Some of these are given in the table. It is seen that the error due to using Method I is exactly half that present in Mr. Bingley's method, and _ that neither of them can be used with U reasonable accuracy for angles much above 45°. On the other hand, Method II is sufficiently exact for angles up to 135\ and even ;it 180 the error is only thirty-nine minutes. In Mr. Bingley's method the middle angle is loo large, and in the other methods it is too small. D. HALTON THOMSON. Kknleith, Broadlands Road, HiGHGATE. N. THE TRISI-XTION ()!•" AN ANGLi:. To the Editors of " Knowledge." Sirs, — In the issue of ''Know- ledge " for November, 1911, I noticed a problem on the trisection of an angle by a geometrical method. As the geometrical trisection of an angle has long been supposed to be impossible, I thought at first (for I am naturally credulous) that a great dis- covery had been made ; but when I tested the matter by a numerical example, the construction, as given by Mr. Bingley, proved to be incorrect from a mathematical point of view, although it gives a rough approximation to the truth. Suppose the angle to be ,. f:,^ divided is 22° 30'. According to the Bingley construction, we obtain the following values for the three divisions of the angle: — 7° 31' 18" 7 27 24 7 31 18 The middle angle shows a deviation from the others of nearly four minutes, and the deviation would be still greater for a larger angle. I leave to the geometrical expert the task of pointing out the fallacy in the construction ; for some fallacy there must be if the construction is supposed to be exact, and not merely an approximation. COM lM"ri~K Boston, Mass. M KNowij-.nr.i:. Fi;iiRiv\kv. 1012. KlJlA r( )I/"K\f)\vr.i;i)C,li." Sirs, — Whilst camped on the Man Kscarpmeiit in this I'rotectoratc, I rcceivcil the l^nis'lish papers K'^'hK accounts of the threat heat experienced in I'tnf^land, and I thought it would be of interest if I took a series of readings showing the temperatures ruling on this plateau. The diagram att.ichcd is the result, and from it will be seen that the greatest tem- perature obtained during the daytime was 71" F. whilst at iiighl it went below freezing. The thermometer was not shaded in any w.ay, but exposed to the full force of the sun from 6 a.m. to 6 p.m. On eleven nights onl of the thirteen that I spent on the Man, there was a heavy frost, the water in the w;ish -basin being covered with ice about a quarter of an inch thick. The ground tem- perature ranged from 30^ to 130° K during the hours of 6 a.m. to 6 p.m. Of cour.se, the Mau Kscarpmcnt is one of the coldest (inh.abifed) parts of British Kast .Africa, and in most of the settled districts in the High- lands, higher temperatures are obtained, but nothing to what one would expect Fipiator as we are. British Fast Africa. 1>. < ... . ,_ 1 , . ,. _^_^ ^'^ -^v _ -_ - __ ^1 __ ^^ : : t -- 5 _ _^-!_ L L _ __ - -> X ^ -^-^ --- / . _H -- » t z _ It ^: ,• __ 3 4:__jL^_ 1 \ M 2 lip IT \, it ^ ' 1 ""^. ' ' -""; " "" ~ ■ '^ ; \ ' ' / M / '- ■ T it .-/ --, -..-'^.^ . i ■■ »! ? ^ : , T J ") ■ ,' ^ ^ '■ " ! i 1 ■ te7 1 Figure 66. Dingram showing Range of Temperature fin open) on Mau Escarpment on October 15th. I'Jll. Latitude about 0° 45' S. Height about 9500' above sea level. situated on the CKOl-TS. A DURHAM 1;ARR0W. To the Editors of " Knowledge." Si rs, — I enclose a photograph (see Figure 67) of a Prehistoric Skeleton and Flint Knife, found in a secondary deposit in the S.E. edge of a round barrow on Batter Law, near Hawthorn, Co. Durham, on June 16th last. Batter Law is a liill forming part of .an elevated tract of glacial debris known as Hesledon Moor, .and rests on the Magnesian Lime- stone. The barrow occupies the highest point of the hill and has a diameter of about thirty-five feet, and height of about four-and-a- half-feet, but has been much disturbed by ploughing and other operations and consequently ob- scured ; it is made of stones and earth. It is not mentioned by Canon Greenwell in " British Barrows." Permission to explore was kindly granted by the proprietor of the ground, Mr. J. S. G. Pemberton. J. P., of Hawthorn Towers ; and 1 started by opening up the S.IC. side of the mound anticipating the possible occurrence of a secondary deposit on the S. or ]'.. side. Almost immediately we encoun- tered a large mass of sandstone set up on edge. ;ind adjoining this a large oblong whinstone boulder ; on clearing away the earth from these a third block was encountered which proved to be a slab of sand- stone fallen down and coxering the feet of the skeleton, the bones of which were found crushed and scattered beneath if. The large whinstone mass proved to be lying across the skeleton where it had probably been thrown when the rough cist was disturbed by ploughing. The skeleton pro\ed to be that of a large and powerful apparently middle-aged man, laid on its right side, facing South, head to the West, the back of the head nearly touching the western slab of the cist, the knees drawn up and the right arm bent round and resting on the left side of the body. The bones of that side of the body in contact with the ground had been largely removed bv solution, but those of the left side were better preserved. The skull was somewhat crushed and the facial bones mostly destroyed, but the dentition was intact and well preserved, except the two upper front incisors which seem to have been lost during lifetime. The skull is now under- going reconstruction and examina- tion in Canon Green well's hands. .Approximately in front of the knees of the skeleton was found a very beautifully- chipped knife of reddish niotdcd tlint. quite sharp and unweathered. It is very skil- fully flaked over the entire upper surface, w hile the under-side shows tlie original surface of the flake, which is untouched except for some slight secondary chipping at the base and towards the point for the purpose of removing .some slight excrescences. It is a good example of a class of implement which have been several times recorded from bar- rows, but not hitherto, to my knowledge, from this county. It measures three - and - five - eighths -inches in length, by one- and-one-eighth-inches in breadth. The occunence of a cist burial as a secondary deposit is unusual: but, perhaps, two upright slabs of sandstone with a large mass of whinstone. whose position is un- certain, can scarcely be truly called a cist ; and may have been uierelv intended to protect and con- fine the body. The cist lay as nearly as possiblv east and west. C.'T. TRKCHMANN. H.Sc. A KNOW'LKOGH OF X.WAI. PICTURES AND PRINTS. i;y A. M. i;kuai)Li:v. (Author of " Xapolcon-iiiCiirictitiirc." vtc.) Thkki-: is no more popular or interesting form of i I'Uecting than that which inchules witliin its sphere of operations the rarioru of the Xav\'. ran tliey do from medals and anto,L;rapli letters to pictures, engraved prints. portraits and caricatures, valentines, songs and jest books. That an impetus will he given to the collection of naval views of every description by the op[)ortune appearance of Mr. Harry Parker's " Naval Battles "' there can be little doubt. Ever since the end of the eighteenth century three generations of the same family have distinguished themselves in the foremost rank of London print-dealers, and now the present head of the firm has brought all his e.xpert knowledge and personal e.\perience to bear on the production of a very delightful volume which is not only an exhaustive descriptive cata- logue of the superb series of engravings formed by Commander Sir Leopold Cust, but affords the humblest collector a useful and intelligible vadc ineciiii). To endeavour to collect naval prints without the aid of such a guide as Mr. Parker has now provided would be sheer folly. If anything could enhance the good work done by Mr. Parker, it would be the admirable introduction supplied by Commander C. N. Robinson, the author of "The British Fleet," whose books may be found on almost every ship of the British, .American and German navies. It is assuredh' in the eternal fitness of things that the namesake and godson of one of the best known and most tlaring of tlie .\dmirals of the Crimean War times should, at the commencement of the twentieth century, have made many important contributions alike to the history and the iconogra[)hv of the Service he loves so well. Commander Robinson points out that the picking u[) of naval prints need not of necessity be a monoi)oly of the millionaire. The intelligent collec- tor will, at the onset, limit his endeavours to one [iarticular channel, and if he does this he will be astonished at the success he achieves in all sorts of out-of-the-way and unexpected places. The writer has seen a large album filled with naval "\'alentines,'" man\' of which throw a curious light on the inner life of Jack Tar during the great wars of the lightecnth centur\-. The same may be said of "chaunties" (a practicalh' inexhaustible subject, for Jack has always lo\cd music almost as much as tobacco or grog) and caricatures. One cannot help holding that in the near future Commander Robinson will deal at length with ■ ; the last-named subject, which has for some \cars engrossed his ; attention. A whole cliapter might be devoted to the British caricatures of Nelson, many of which are very interesting as sidelights of naval history. Napoleon, for some reason or another, ne\er incited his official cari- caturists to lampoon Nelson as they did Pitt. The only French cariraturi' of Nelson the writer hn'= cx-er mi't with i I iiiUKi: 7(1. KNowi.i.nr.K. Frhrtaky. I'JK represents a corpulent oflicer witli a f^rotescpic lu iui. wearing a lingo cocked liat and standing up in a tiny boat, which is being rowed by a diminutive sailor. I'nder his arm is a huge official portfolio, and besitie him a letter addressed to Lady Hamilton. NapoK'on evidently knew tin- weak point in his atlversary"s armour. Sir Charles Cust has himself specialized in the w;iy Commantlcr I\oi)inson indicates. We are told that: — He has gathered together every engraving which in any way ilhistrales his own particular subject — British battles by sea. The collcclor who acts nn ihese lines, and selects a definite subject possessing a personal .ittraction and connection, has one great advantage over the more orthodo.x coinioissenrof prints; for lie does not want to worry about " states" or " margins," or other points which re(|uirc special knowledge, if not a thorough technical education. The intrinsic v.iluc of the print for him will rest in its subject, and although he may desire and .ippre- ciate technical beauty if he can get it, it will be less an object than human and historical interest. The pleasure of picking up — perhaps as a bargain — yet another example, and adding it to one's gallery or cabinet, can only be .adetjuatelv realised bv the ardent collector. Sir Charles Cust has succeedeil in olitaining no less than seven hundred aquatints, engravings and lithographs relating to British naval achievements at sea. He begins witli Julius C;esar's invasion of Britain in 55 B.C.. and ends with the operations at the entrance of the Pei-Ho River on June _'5th. 1859. For Sir Charles Cust the piquant satirical print has apparcntl\' no charm, nor is any nietitioii made of the numerous glass-pictures which for long years decorated the mariner's cottage and kejit green the memor\- of Nelson, the Dorset Hoods ami Sir Thomas Hardy. .\t least twenty of these (piaint illustrations relate to the tragedy of Trafalgar. A few of them possess a certain amount of artistic merit. To those who reside on or near the English littoral this book will prove exceptionally interesting. Many of the keenly-contested engagements whicli lia\e been fought within sight of our shori's are almost forgotten. Most Dorset men, for instance, are aware of the discomfiture of the Sjianish .Armadaoff Portland Bill in the eventful summer of 1588, but some seventy years later a scarcely less important action took |)lace in the same waters. The second "l^attle of Portland" took place in February, 165.5. and lasted three days. The best known of the Fnglish admirals engaged were Blake, Monck, Peacock, .Martin and Penn, and in the end they gained a signal triimiph over Tromp and de Kuyter: — About twenty luiglish ships were first to engage the enemy, .md were nearly annihilated by the overwhelming number of the Dutch, but as soon as the remainder of the fleet arrived the Hutch endeavoured to make their escape, and on the 19th arrived olf the Isle of Wight. Hlake (who had previously won .in abundant crop of laurels on land at Bridgwater, Taunton and Lyme Regis) then reengaged with great desperation, and after a most valiant fight drove the enem\- before him and captin-cd or destroyed eleven ships of war and sixty merchant- men. One thousand five hundred men were killed and seven hundred taken prisoners. Sir Charles Cust has discovered no less than four illustrations of this comparatively little-known engagement — one of Fnglish origin (dated 1803). and three Dutch. M. Kiisell jiublished an etching of the battle as early as March 24th. 1653. Curiously enough, the name of that gifted artist, Tho)nas Kowlandson, docs not appear in Mr. Parker's carefully i)reparcd index. This is probably explained 1)\- the fact that Rowlandson's naval pictures were not, strictK' speaking, descriptive of actual engage- ments, although the reproductions of the two original (haw ings in the present writer's collection obviously relate to na\al warfare. .\s far as the writer is aw are, engravings froin these admirable water-colours do not exist. They may be supplemented very efte(ti\i'I\ by the spirited and striking sketch by ■ W. H. " which shows the " \'ictory " as she apjjcared just fifty years after Nelson's death and the date of Rowlandson's drawings. THE ROVAI. .\NTIlR<)l'()T.O(^,ir AT, IXSTITUTE. Mk. Ai.frkd p. M.xudslay, F.S.A.. I'.K.C.S.. delivered his Presidential .Address at the Annual General Meeting of the Roval Antliro|)ological Institute, on Tuesday, January i.inl. .Mr. Maudslay said that even at the present day the idea that the origin of man does not form a tit subject for scientific enquiry has not yet entirely died out. and this feeling has militated against anthropology becoming a popular study. Meanwhile the im- mediate and energetic [irosecution of anthropological studies is of vital necessity, since the material with which this science deals is becoming rarer every year, as primitive customs \ield to civilization. The fact that man's plusique is less subject to alteration gives a permanent \alue to the stud\- of physical anthropolog\-. Mr. Maudslay confined the bulk of his remarks to certain points in the aichaeologN- of Ameiira. while there are traces of many extinct civilisations. He iiicidentallv jujintedout that manymisunderstandings between European and barbarous races might be avoided by a knowledge of elementary- anthropolog\-, and inentioned that the Institute had never ceased to press upon the Government the advisability of establishing in this country an anthropological bureau, which would be of material assistance to colonial administration. The address terminated with an appeal to all fellows of the Institute to do their utmost to make a success of the International Congress of .Americanists in London, which will be held during May. 1912, saving that though we possess in luigland more pre-Columbian objects of interest than are preserved in aiiv other European country, it is the first time that we have acted as hosts to the leaders of .American research. RK\'11":\\'S. BIOLOGY. Life ill the Sea. — By James Joh.vstone, B.Sc, Fisheries Laboratory. L'niversity of Liverpool. 150 pages. Numerous illustrations. 6'! -in. X 4it-in. (Cainbridse University Press. Price 1 - net.) This is a fascinating introduction to a study of the economy of the sea, a department of marine biology which has made great strides within recent years, partly thiough the quantita- tive plankton investigations which estimate the productivity of a sea-area and partly through the correlation of the minute life of the sea with currents and other physical conditions. Mr. Johnstone has been .actively engaged in marine biological investigations for many years past, and he tells his tale with vigour and clearness. He starts off with an imaginary walk along the sea bottom to North .-Vmcrica. which introduces the reader to a v,ariety of zones and faunal areas. His second chapter is devoted to rhythmical changes in the sea, — "the tides, the annual waves of temperature, salinity and sunlight ; annual outbursts of animal and vegetable life ; animal and plant migrations; spawning periods; fishery seasons and the like." In an admirable analysis of the factors of distribution — the subject of Chapter III — Mr. Johnstone discusses many interesting facts, such as that the polar and temperate seas are. generally speaking, far richer in life than are tropical seas, and the lengthening out of life at low temperatures. To our thinking the author speaks the words of wisdom when he notes in regard to migrations that it seems to be rather straining after generality to describe all these as tropisms, and that the behaviour of an animal at any time is modified by its past experience which is registered within it. In the fourth and fifth chapters the different modes of nutrition and the sources of food are discussed, and attention is paid to the recent theory or heresy that many mai-ine animals feed '' saprozoi- cally ■' — by the absorption of dissolved organic matter in the sea, on the stock of the sea-soup as it were. The amount of carbon compounds (other than carbonates) and of nitrogen compounds (other than ammonia or nitrates) dissolved in sea water is small, but it is greater than the amount of proteid or carbohydrate contained in similar volumes of water in the form of plankton. We cannot do more than indicate the general trend of this delightful and stimulating volume, which we would recommend with the greatest cordiality. It should not be missed by any one interested in the science of the sea. J. .\RriirR Thomson. CHEMISTRY. Some Chemical Problems of To-day.— \h- K. K. Dlncax. 5-t pages. 34 illustrations. Si-in. X 5i-in. (Harper & Bros. Price 2 dollars net.) Professor Duncan is an enthusiast in the matter of technical chemistry, and his book is a veritable mine of suggestion upon the practical applications of the science. In every industry there are chemical problems in pressing need of solution, and here we have an outline of many of these difficulties, which will tax all the resources of the trained chemist to meet. .And is not. so the author urges, an education which tends to the solution of such industrial problems as good an intel- lectual training as that usually given ? His attitude upon this question may be summarised in his own words : " The many and important actual opportunities that lie everywhere at hand for applying scientific knowledge and the scientific method to the manufacturing needs of men make one frankly consider why trained and earnest men should devote laborious days to making diketotetrahydroquinazoline, or some equally academic substance, while on erery side these men are needed for the accomplishment of real achie\ement in a world of manufacturing waste and ignorance." But. although America has greater facilities for meeting this need than we possess in this country, yet we find Professor Duncan lamenting that " the present state of American manufactures is one of inefficiency." The picture he draws of the position of the research chemist in American works is not a pleasant one to contemplate. He has no security of tenure, and in most cases works under unsuitable conditions, and while his retaining his poorly-paid position depends upon speedy returns for his work in cash, he is rarely given any pecuniary interest in his discoveries, which become the property of his employers. This is the impression left by this part of the book, and the outlook for the future does not appear very hopeful. But it is not only in the direction of applied chemistry that the reader will find much to interest him in this brightly written and stimulating book, for there are also excellent chapters on " The Question of the .-\tom. I'he Chemical Interpretation of Life," and "The Begiiming of Things," in which is given a clear outline of Chamberlin's planetismal hypothesis, illustrated by a series of beautiful photographs of spiral nebulae, which were taken at the Lick Observatory. The book is so well worth reading in every part that we can forgive the use of words and expressions that grate upon Knglish ears. But why should the author go out of his way to talk about the "young chemist seeking an arbeit" or "The trained chemikcr," when we have I-'nglish words to convey the same ideas ? CAM Chcinieal Phenomena in Life. — By FREDERICK CzAPEK, M.D.. I'h.l). (Harper's Library of Living Thought). 152 pages. 7-in. X4i-in. (Harper and Bros. Price 2 6 net, cloth; .5 0 net, leather.! In this welcome addition to a well-known series of short monographs Professor Czapek gives a concise, yet readable, account of the present state of our knowledge of the chemical processes involved in what is commonly understood by " life." The book deals more especially with the biological chemistry of plants, and only incidentally with the allied phenomena of animal life. .After a short historical survey of the connection between biology and chemistry, chapters are devoted to proto- plasm, colloidal chemistry, the chemical action of living matter, enzymes, and chemical adaptation and inheritance. Owing to the necessity for severe compression within a small space the subject lacks sufficient elaboration in places, while, on the other hand, it occasionally goes into more detail than is suitable for a book intended for the general reader rather than the specialist. The author does not attempt to evolve a chemical definition of life, although he lays stress upon many facts tending to- wards such a definition. Thus, qn page \9 he writes, " The final result of our discu.ssion is that there are many reasons for maintaining that protoplasm really is of a peculiar chemical constitution, and that it does not merely represent a mechanical structure." In this connection it may be mentioned that in several places an attemi>t is made to draw too sharp a distinction between living and inorganic matter, as, for example, on page 10, where it is stated that the chemist studying inorganic matter " will be accustomed to see thai no change takes place in the matter under investigation unless an experiment be made." This ignores the continual changes which recent researches have proved to be taking place in radio-active and (not improbably! other bodies, with the degradation of one form of inorganic matter into another — changes which in the more rapid cases we can follow, but cannot influence by any experimental means at our disposal. ^^ ^_ ^^ 67 KN()\VLi:nr,i:. Feiiruarv, 1912. A ILiiulbook of Oriitinic Ainilysix. - Bv II. 1 halH1-,i< Clarki;, H.Sc. (Loud.), A.I.C. J(i4 |ugcs. 23 illustrations. 7J-in. X5iii. (lidwin Arnold. Price 5/- net.) This small book should meet the long-felt want of a concise text book upon organic (|ualitative analysis. It deals system- atically with the identification of different organic radicles, and organic compounds, anil gives a new and most useful classified table of the physical properties of the more common substances. This table will obviate the necessity of freciucnt references to chemical dictionaries or larger te.Nt books; in future editions it might with advantage be amplified so as to include some of the important com- pounds omitted. The section of these tables dealing with the identification of different classes of dyestuffs will pro\e p.irticularly valuable. The latter half of the book, which deals with the quiintil- ative analysis and determination of the physical properties of organic compounds, does not present the same novel features as the first part, though it describes clearly, and at sufficient length, the ditTerent methods of estimation. Kven processes not ordinarily found in elementary handbooks, such as, for example, Wijs' method of determining the halogen absorption of unsaturated bodies, are here fully described. The book is well printed, and illustrated with diagrams where necessary, and we can thoroughly recommend it as a laboratory companion both to the student and advanced worker in organic chemistry. C. A. M. CRYSTALLOGKAl'HY. Crystallography and Practical Crystal Measurement. — By A. E. H.TUTTON. D.Sc, M.A. (OxonI, F.R.S., A.R.C. Sc. Vice-President of the Mincralogical Society. 946 pages. 720 figures in the text and 3 plates. 9-in.X6-in. (Macmillan & Co. Price 30/- net.) The subject of crystallography being one which claims so few ardent students in this country, it is perhaps not to be wondered at that English authors and publishers have for some years refrained from any large and exhaustive publication on the subject. The fine work which has now been published will be heartily welcomed by all crystallographers and will undoubtedly rank as a standard work on the subject. As its title imphes, the book is intended as a guide to the practical measurement of crystals rather than as a complete text-book of crystallography. The author has made every effort to remove all grounds for the assertion, so frequently m.ide, that crystallography can only bo studied by mathe- maticians. .Accordingly, while pointing out the real need of a knowledge of higher mathematics for tlie thorough mastering of crystallography, the author has reduced the computation of the physical constants of crystals to the application of some four pages of simple formulae, all geometrical or analytical proofs of these formulae being omitted. The first part of the book is devoted to the morphological characters of crystals. A few pages on the nature of crystals serve as an introduction to accurate instructions for the growing and selection of crystals suitable for measurement. The simplest types of goniometers are then described in great detail, and in the fourth chapter the knowledge alreadv obtained is shown to be sufficient to enable the reader to measure completely a crystal of potassium sulphate. After devoting three chapters to the conceptions of crystal axes, face indices and zones, and to the stereographic projection, and the few simple formulae mentioned above, the results of the measurcnients Tuade in Chapter IV are worked out. The simplification of the mathematics has. perhaps, boon carried a little too far and strikes one as being somewhat inconsistent. Thus, while elaborate pains arc taken to explain the application of Napier's rules, the reader is left in entire ignorance of the signification of the " zone indices," which are obtained by cross-nmltiplying the indices of .any two faces in the zone. The reader who has little knowledge of mathe- matics ni ly at first fail to appreciate Chapter IX, which is a truly brilliant resume of the mathematical work on cr>-stal- structure, ;ind will no doubt appeal more to advanced students. The seven crystal-systems are next studied, commencing with the cubic system, as being the one re(|uiring the simplest calculations, and leading gradually up to the more difficult systems. Two chapters are devoted to each system, one deal- ing with the elements of symmetry and possible forcns in the various classes, the other giving examples of crystals measured by the author, each one completely worked out. the results being tabulated in the form adopted in publications of crystallographic data. The methods employed for drawing crystals are clearly set forth in Chapter XXV, again with the aid of as little mathe- matics as possible, but calling attention to Penfield's excellent methods based on the stereographic projection. Twinning and planes of cleavage and gliding are dismissed in two short chapters, and the first part of the book concludes with a description of recent advances in goniometry. the determina- tion of density, and a clear account of the theories of crystal- structure put forward by Fedorov and by Pope and Barlow. this last chapter being a most valuable contribution. The second part deals mainly with the optical properties of crystals and no pains have been spared to make this part thorough. The chapter reviewing recent ideas on the nature of light .and the three succeeding chapters pave the way for the study of the transmission of light through uniaxial and biaxial crystals. The determinations of optical constants are described in the same detailed manner as the measurements in the first part. Two chapters on the crystallographic microscope are full of useful suggestions and descriptions of the most recent methods. The remaining three chapters are occupied with thermal expansion, elasticity and hardness, with a brief summary of the recent work on liquid crystals. Throughout the book the treatment is better suited to chemical crystallography than to mineralogy. .X sufficier.t supply of material of the highest degree of purity and of perfect crystal development is postulated, and the mineralogist may frequently find himself unable to attain the degree of accuracy which the author has shown to be possible wiih crystals grown under suitable conditions. This book, how- ever, sets before all crystallographers an ideal at which to aim. and it is to be hoped that its influence in this direction will be widely felt. The fact which adds enormously to the value of the book is that every branch of the subject which is treated at length is one to our knowledge of which the author himself has contributed very largely. Consequently, we have in this book the results of years of experience in carrying out most accurate and laborious measurements. The care and accurate detail with which the book has been written yield most eloquent testimony to the untiring patience and accuracy which characterise all Dr. Tutton's work. The figures with which the book is lavishly illustrated are most beautifully reproduced, and the publishers, as well as the author, are to be heartily congratulated and thanked for so valuable a publication. ... „ ^ MEDICINE. The Art of Life — The Way to Health and longevity. — By J. L. Chundr.-\, L.M.S. 240pages. Illustrated. 7.\-in.X 5-in. (Calcutta University. Price 3 - net.) This interesting little book is unique in many ways. The author is clearly a man of very wide reading, and gives us the combined wisdom of the East and West. Thus we find ijuotations from the Hindu Scriptures and from the latest .American medical journals on the same page, and while ordinary medical prescriptions are given, we are also told that "' Persons who have been given up to die are often restored to perfect health in a few minutes by the hands of the Magnetic Healer." Tlie author has written his book for the laity and medical profession alike, but the inclusion among its " varied and valued ingredients " of detailed medical prescriptions and full descriptions of indolaceturia. cretinuria, and so on, would Febkuakv. 191: KN()\\I.i;i)(".l 69 seem to our Western iniuds a little undesirable if the laity are reallv expected to read it. Moreover, the English is in places a little obscure. .Among some excellent rules for the care of infants we read: " Don't forget to put the child in the sun or sunshade for two hours at least a day." Nevertheless, the book contains much sound, practical, useful advice, particularly applicable to those resident in w.irm countries, and e\ery page shows us that the author, if a little over-credulous, has considered most carefully the problems of existence, and knows how to express his meaning clearly, tersely and in a very interesting style. Further Researches into Induced Cell-reproduction and Ciineer. By H. C. Ross. The McFadden Researches. 63 pages. 5 plates. 9-in. X 5i-in. ijohn Murray. Price 3 6 net.) The present volume contains a series of papers by Messrs. H. C. and E. H. Ross and J. W. Cropper, on certain changes which they have observed in red and white blood corpuscles, when these are supported on a film of jelly and various chemical substances are made to act upon them. The researches here described are a continuation of those recorded in a volume published a year previously, a review of which appeared in "Knowledge" for March, 1911, and many of the observations therein made apply with equal force to the present editioTi. There can be no doubt as to the care and accuracy of the observations recorded, and of the value of the methods which the authors have introduced. Whether in all particulars they are correct in the interpretation of their results is a question upon which pathologists are still divided. No one will, however, doubt that both volumes form a valuable contribution to the phvsiologv and pathologv of the blood. MINERALOGY. The World's Minerals.— By Leonard J. Spencer. M..A., I'.Cr .S. 212 pages. 61 illustrations. 8i-in. X 55-in. tW. & R. Chambers. Price 5/-.) The author of this book is an official of the Mineral Depart- ment of the British Museum and is the editor of the Mineralogical Maf^azine. In 1904 he translated from German, into English, the beautiful work upon precious stones by Dr. Max Bauer of the University of Marburg, and also m.ade certain additions to the text. We believe that the English edition of this work is now out of print. In the preface to "The World's Minerals" the author tells us that the book deals with one hundred and sixteen of the more simple minerals, which are illustrated by one hundred and sixty-three figures in the coloured plates, and that mention also is made of the various applications of minerals, their importance as ores of metals as precious stones, and so on. We are sure that the information given of the various minerals is in every way correct, especially considering the position which the author has so long occupied and the work which he bas previously done. We find, however, that in some cases the descriptions are so meagre as to be somewhat misleading. .As an example of what we refer to we may quote Spinel, which is described as a red mineral occurring in the cubic system, which when cut as. a gem somewhat resembles the ruby in appearance, but the author does not tell us that it also. in different specimens, is green, blue, brown and violet. We also cannot quite understand why such a mineral as chrysoberyl. with its important gem-stone varieties, has been omitted. On page 90 the author describes the fibrous variety of quartz as catseye. and refers the reader to an illustration stated to be made from a specimen from Ceylon. Now. the beautiful catseyes of Ceylon are a variety of the mineral chrysoberyl. and they rank among the most important precious stones, w-hilethe chatoyant quartz is a stone of quite minor consideration, commercially, and in every other respect, although it slightly resembles the chrysoberyl catseye in general appearance. The writer does not explain this, nor is it apparent that he is aware of the fact. The book will probably be welcome, for it is written in such a clear manner that e\ery student will be easily able to under- stand it. The coloured plates are very numerous and add consider- ably to the value of the work. They have been prepared under the supervision of Dr. Hans Lenk, Professor of Mineralogy and (ieology in the University of Eriangen, and many of the pictures represent actual specimens belonging to the collection under his charge. Here and there we take exception to a shade of colour, but this is probably due to the process of reproduction. In the early pages of the book the author gives an intro- duction to the study of minerals which will be most helpful to the student. Chapter 2 is devoted to " The Forms of Minerals," and we notice here that crystals are classified under seven systems and not six as is customary, and we rather wish the author had given us his reason for doing so. The book has an excellent index, which appears to be reliable. PHYSICS. Physical and Chemical Constants and some Mathematical Functions.— By G. W. C. Kaye and T. H. Laby. 153 pages. 9ii-in.X6j-in. (Longmans, Green & Co. Price 4 6 net.) The authors have compiled a most useful book of reference. It is remarkable how much is to be found in this thin book of one hundred and fifty pages. One can find within all the data which one is constantly requiring to look up during one's work in the laboratory, except, of course, the less common constants, which one could hardly expect to find even in Landolt Bornstein and Meyerhoffer's '" PhysikalischChemische Tabellen." For instance, one would find the boiling point of pentane but for the melting point, which is somewhere below — 200° C one would have to search in some original paper. The book is very concentrated, and as a reference book is therefore, all the more useful. It commences with the units, and passes on to astronomical data, then follows a very com- plete set of data in the subjects of heat, sound, and light. The section on radioactivity and gaseous ionisation is excellent and gathers much valuable work together in a set of excellent tables. The Chemistry section is necessarily rather curtailed, but the chief properties of all the commoner chemical sub- stances are to be found in two tables of the physical constants of inorganic and organic substances. There is a short table of solubilities in water of a few common substances, but a complete solubility table requires a large book of its own. The mathematical tables at the end, though only occupying eighteen pages, are those that are most generally needed and are very conveniently arranged. .\ table of the exponential c "* will be very useful to students of r.idioactivity. .\s far as one can judge, the tables are reliable and thoroughly up-to-date, while the recently-formed international committee for the yearly publication of physical and chemical constants will help to make it the easier to keep the book abreast of the times. The value of the book is enhanced by brief references to books and original papers which have bearing on the various subjects under consideration. The book is excellently got up and thoroughly suitable for the laboratory. ZOOLOGY. Primitive Animals.— By Geoffrey Smith, M.A., Fellow of New College, Oxford. 156pages. 25 figures. 6i-in.X4iJ-in. (Cambridge University Press. Price 1/- net.) It was a happy idea on the author's part to give this intro- duction to the study of phylogeny a concrete and picturesque basis in a series of " primitive animals " or old-fashioned types, Uke Peripatus and Platypus, .\naspides and Amphioxus. " Relics of a distant past, the features of which have been all KNowiJ'.nr.i- I'l IIRIAKY. l')12. but effaced by the passnui' of time, they preserve for lis <'i record of bvKonc phases of existence, and often point us to some of the sources from which the modern world of livinK things has arisen." PliyloKeiiy, or racial history, seems to be a red rap to many /ooioRists to-day, because of considerable recklessness in pcdiKree-makinj,' in the early days of Oarwinian cntlinsiMsni, but it seems a pity to react to the extent of leaving the doctrine of descent as a sort of abstract fornnila of an evolution-process, which has no doubt occurred, but of which the less we say the better, since all is so uncertain. Mr. GeofTrey Smith is not one of the extreme sceptics as to the iwssibility of phyloRenetic conclusions, for though he does not think that we can speculate to nood purpose in regard to the inter-rclationships of phyla, he believes that within the limits of the fjreat fjroups " coiiiparativo morph(ilof;y has supplie ... 4 27 5 ... 16 53 18 ... 4 27 FKKATL'M LAST MONTH.— In the t.able of errors of Encke's Comet, insert the word " iiiiniis" between " Observed " and " Computed." BOTANY. Hy Professor F. Cavers, D.Sc, F.L.S. MUT.ATION IN SHEPHERDS PURSE.— From time to time more or less strikingly abnormal forms have been described in the widespread and very variable Shepherd's Purse. For instance, in 1886 (Bot. Ccntralblatt. Hand 26, page 121), Wille pointed out that various earlier observers had described abnormal forms of such Crucifers as Wallflower and Charlock, which had more than the usual number (two) of carpels, the number in some cases being as great as six, but more often four. In some Crucifers there are normally four carpels, and a four-valved fruit, c'.^>. Holargidiuin and Tctrapoma. Wille had seen, in 1883, a single Shepherd's Purse plant with three abnormal fruits which had three, four, and six wings respectively. The three-winged capsule had three valves, one complete and one incomplete partition, and six rows of seeds; that with four wings had four valves, two complete partitions, and eight rows of seeds : while that with six wings consisted of an ordinary two-valved fruit fused with a four-valved one, the stigmas being separate. In 1900 iBot. Zcitiiiig, Band 581, Solms-Laubach described a form which may be regarded as having arisen by nmtation from the common Shepherd's Purse tCapsclla bursa- pastorisK This new species iCapsclla heeneri^ had appeared suddenly and spontaneously, and on being cultivated for several years retained its characters, that is, bred true from seed — it is an annu.al plant, like ordinary Shepherd's Purse. Excepting for the structure of its fruit, C. hcciicri resembles a variety of C. biirsa-pastoris with the radical leaves pinnately cut. The capsule, however, is egg-shaped, showing neither the flattening nor the two humps char.acteristic of C. bursa pnsloris, and has at its base a short thick stalk. Solms regards this new species as having arisen by mutation from CapscUa bursa-pastoris, since its characters arc constant and the fruit is widely different — sufliciently so. in fact, to justify its being placed in a new genus. Shull (Proc. Int. Zool. Congress, Boston, 1907 ; published in 1910— abstract in Hot. Ccntralblatt. Band 116. 19111 isolated four types or elementary species of Ca/ysclla bursa- pasloria differing in leaf characters, and foimd that in cross- ing they behave as a Mendelian hybrid. Keciprocal crosses were then made between C. Iiccucn and the simplest of the four elementary species of C. biirsa-pastoris. In this way four elementary species of C. Iiccficri were produced, the leaf characters of these hybrids showing Mendelian ratios, but the liccucri capsules appearing only in about one plant in two hundred and twenty-three of the second generation Isec Figure 2). Hlaringheni i/Jh//. Sci. France cl Bcli>.. 1 ha;- recently described another new form of Capsclla. a single specimen of which was found growing among abundant C. bnrsa-pastoris. This history of this new species IC. viHHicri\ parallels that of C. luxiicri, but C. vi)>uieri shows a variation of the capsules in the opposite direction from that presented by C. Itccgcri. Thegreat majority of the capsules have four valves, resembling the two valves of C. bursa-pastoris and placed at right angles to each other, but the number of valves varies from two to eight. Counts of nearly ten thousand fruits showed : — Two-valved, 2; three-valved, 81: four-valved, 8450; five- valved, 301 ; six-valved, 288 : seven-valved. 24 ; eight-valved, 16. This new species is normally fasciated. and breeds true to this character as well as to the high number of valves. The leaves are almost entirely unlobed. Solms, Blaringhem, and Wille (whose paper appears to have been overlooked by later writers on the subject, but has been consulted by the present reviewer) lay stress on the fact that several species of Cruciferae have four-winged capsules. It is quite obvious that several species of Tctrapoma would, if two-valved, be classified as species of Nasturtium : the genus Ilolargidiuni, if two-valved. would be merged in Draba ; while the Californian genus Tropidocarpon has one species with two valves and one species with four. Moreover, four-carpelled varieties, both cultivated and wild, are known in such genera as Cheiranthus. Brassica. Isatis. and other C'rucifers. Such instances as these, of the recurrence of similar characters in more or less closely related species or genera, support the view that variation is definite, or "ortho- genetic," rather than entirely fortuitous. In reviewing Blaringhem 's paper. Shull {But. Gaz.. Jime. I'll II remarks that mutations probably occur in Nature as frequently, in proportion to the percentage of the seeds which succeed in germinating and developing, as in experimental cultures, but actual proof of such mutation is necessarily wanting, as a rule. When a single individual of a hitherto unknown type is seen to difl'er by some marked characteristic from the associated typical individuals of the most closely related species, the natural inference is that the non-typical plant is a mutant. Such evidence is strengthened if the plant is found to reproduce its characteristics in its ortspring. but there remains the question of possible hybridisation ; and if even that be satisfactorily ruled out, there is the possibility that the form in question is not itself a mutant, but the oft"- spring of a mutant, which appeared in some preceding genera- tion. This last (juestion cannot, of course, be cleared up in any case, but it is of no essential importance. BROWN FLAGELLATES AND BROWN ALGAE.— Pascher has recently published two interesting papers ( Bcr. d. dcutsch. bot. Gcs., 1911) de.iling with Brown Fl.igcllates and the relations of these to the Brown .-\lgae. In the first paper he gives a short account of two new- genera of Brown Flagellates. Cryptochrysis. which was only observed in the motile state, resembles other Flagellata in having no cell-wall and in dividing by a plane parallel to the long axis of the body, which is an ellijisoid inas^ of protoplasm : the broader notched anterior end bears two whip-like flagella. and the protoplast contains two brown pigment-bodies. Protoclirysis is also ellipsoid but curved and bean-shaped, with two flagella in.serted at the middle of the concave side ; the chrom.itophores, two in mnnbcr, may be reddish or blui.sh-green in.ste.ad of brown : division occurs In a motionless condition, the cells rounding olV, becoming surrounded by a swollen membrane and dividing into colonies of from four to eight cells. Feisri-arv, 1912. KNOWLEDGE. 73 The Flagellates included by Pascher under the family Cryptomonadinae are rather few, the most interesting (in addition to the two new genera just mentioned) being Zooxan- thcUa which lives in symbiosis with lowly animals like the Radiolaria. The Crj-ptomonads are distinguished from the other Flagellates, especially the Chrysomonads. by the remarkabK- dorsiventral or one-sided (as opposed to radial) symmetry of the body, which is obliquely truncated at the anterior end : the presence of a curious furrow, which is usually in the longitudinal plane but in Protochrysis is e(|uatorial: the frequently red or blue tinge of the usually brown chroinatophores ; the unequal pair of cilia inserted in the furrow. Starting from the simple Chrysomonads, these probably gave rise to the Cryptomonads. and the red and blue varieties of I he latter then became fixed characters in the red genus Rlioiloiiioiias. which may be regarded as the direct Flagellate .incestor of the Red .\lgae, and in the blue-green genera CItrodiiioiias and Cyanomonas, which may have given rise to the Blue-green Algae. A third line arising from the Cryptomonad group (t-.^.. Cryptochrysis and Protochrysis) passed through Cryptomonas, in which the apical furrow L;radually becomes deeper and forms an " oesophagus " (a ■ .ivity which extends more or less deeply into the protoplast, lud into which the contractile vacuole opens) ; this line of l.irger and more highly organised forms ends blindly in heterotrophic (saprophytic) genera like Chiloiiwnas and Cyatlwutoiias. The most important line arising from the Cryptomonads, however, is that leading through the remarkable series of I'haeocapsaceae to the higher Brown Algae. The I'haeocapsaceae correspond, in the Brown Series, to the I'etrasporaceae in the Green Series leading from Green I'lagellatcs to Green Algae. In the Phaeocapsaceae we get a series of forms passing almost insensibly from true Flagellates to true though simple Brown Algae. The first known member ill this series is Pliacoplax marina (formerly called Pluicococcus inarinits). In Pliacoplax. the motile reproductive cells exactly resemble Cryptochrysis, having the same dorsiventral symmetry and the same minute structure, but the plant passes the greater part of its existence in the motionless condition, dividing to form a mass of cells enveloped by mucilage derived from the cellulose walls (the Cryptomonads themselves have no cellulose walls). Through forms showing increasing suppression of the motile phase, and increasing elaboration of the cell-masses formed by division in the resting stage, we come to the genus Phacothaiitiiion. which forms branch filaments and produces sexual reproductive bodies (gametes) — sexual reproduction does not occur in the Cryptomonads or any other Flagellates so far as known. Pascher's paper is an interesting contribution to the evolu- tion of the .-Mgae from Flagellates. The phylogeny of the Green Algae has been worked out in great detail — see Black- man's well-known paper yAnnals of Botany, 1900) — but less is known concerning the relation of Brown Flagellates to Brown .Mgae, and still less regarding the Red and Blue- green Flagellates and Algae. Still, there seems to be little ground for doubting that the Brown, Red, and Blue-green .■\lgae have arisen from some such Flagellate group as the Cryptomonads. CL.-\SSIFIC.\TION OF BRVOPHVTA.— At the end of a series of papers on "The Inter-relationships of the Bryophyta" in the A't-K' Phytologist, the present writer has proposed a new classification of this group of plants. The old-established primary division of the Bryophytes into Mosses and Liver- worts is called in question, especially in connexion with the small families .Anthocerotaceae and Sphagnaceae ( Peat Mosses), and it is interesting to note that in certain of the characters which have been regarded as ext;luding the .-Vuthoceros family from Liverworts on one hand, and the Sphagna from the Mosses on the other, these two aberrant groups show a strik- ing resemblance to each other. After discussing the advisa- bility of dividing the Bryophytes into four classes — true Liver- worts, Anthocerotes, Sphagna, and true Mosses — the writer proceeds to elaborate a new classification. It is proposed to divide the Bryophytes into ten independent groups, as follows : — I. — Sphaerocarpales, including Sphaerocarpaceae (Sphacro- carpus and Gcothallits) and Riellaceae (Rielta). II. — Marchantiales, including Ricciaceac, Corsiniaceae, Targioniaccae, Monocleaceae, Cleveaceae, Aytoniaceae, and Marchantiaceae. III. — Jungermanniales, including the Anacrogynous families .Aneuraceae, BIyttiaceae, Codoniaceae; the transitional family Calobryaceae ; and the .\crogynous families Lopho^iaceae, Ccphaloziaceae, Ptilidiaceae, Scapaniaceae, Radulaceae, Pleuroziaceae, Porellaceae, and Lejeuneaceae. IV. — Anthocerotales, including .Anthocerotaceae. V. — Sphagnales, including Sphagnaceae (Sphagnum). VI. — .-^ndreaeales, including Andreaeaceae (Andrcaea). VII. — Tetraphidales. including Tetraphidaceae. VIII. — Polytrichales, including Polytrichaceae and Dawson- iaceae. LX. — Buxbaumiales, including Buxbaumiaceae and Diphys- ciaceae. X. — Eu-Bryales, including all the higher mosses. .Ml these groups are characterised and their relationships discussed. The arrangement of the lower Bryophytes is based largely on the writer's own work, while for the higher mosses (Eu-Bryales) the writer accepts the views of Lorch, Philibert, and Fleischer, with some modifications. The classification of the higher mosses can no longer be based upon such characters as the position of the fruit (the old groups .\crocarpi and Pleurocarpi) nor upon the presence or absence of a peristome (Stegocarpi and Cleistocarpi of previous authors), though the various terms — acrocarpous, pleurocarpous, stegocarpous, cleistocarpous— may be retained for purely descriptive purposes. In the new classification of mosses proposed by the writer, the Fn-Bryales are divided first into Haplolepideae, Heterolepidcae, and Diplolepideae, according to the single or double character of the peristome, and the various cleistocarpous forms are simply distributed through these groups according to what appear to be their aftinities as either reduced or primitive types allied to difterent peristome-bearing families. The further division of the great group Diplolepideae is based upon minute, but readily observable, differences in the structure of the peristome. Throughout this series of papers, it is assumed as a working theory that the Bryophyta form an ascending series, marked by progressive elaboration of the sporophyte ; that the sporogoni'.nn of the Bryophyta has arisen as an interpolated generation, with increasing " sterilisation of potentially sporogenous tissue," from the segmented oospore : that although the archaic condition in which the sporogonium was a simple spore-fruit consisting of a mass of sporogenous cells, is not actuallv realised in an\- known Bryophyte, we have in the Ricciti capsule a primitive sporophyte in which sterilisation has proceeded only as far as the formation of a single peri- pheral cell-layer forming the capsule-wall ; and that the Riccia type of sporogonium is not only the simplest but also the most primitive known. This theorv has been much disputed, but at any rate the question is apparently still an open one. The writer's object in this series of papers has not been so much to discuss the position of the Bryophvta as a whole and its relations to other divisions of the Vegetable Kingdom, as to give a summary of the various families of Mosses and Liverworts and of their relations one to the other. The ■■ Inter- Relationships of the Bryophyta" is obtainable separatelv. as a " ATetc' Phytologist Reprint.'' from the Editor of theA'e'tc- P/j>7o/og;s^ Botany School. Cambridge University (price 4 -, postage 4d.) ; it contains numerous illustrations and full lists of the Uterature of Mosses and Liverworts. K\n\\ 1,1 DGi:. I-KHIOM. Hydro. Nilro. gen. .Vsh. Tar. .'Sulphur. Chlor. Acidity. o«, .. . 69-30 4-89 '■39 8-48 1-64 '•74 0-I7 0*'J0 DumcAtic Soot . . 40-50 4 '37 4-09 i8-i6 25'9" 2-09 5">V u'S? Koilcr Sooi, ai Ikisc .. 1666 0-S6 o'ou 75 '04 0-09 J -07 o-ii ■•37 Itoiler SooI, 70-rt. up ji-8o '■44 118 66-04 080 =■38 1-46 o-jB lioikr Soot, al top, I lo-f'.. up 2700 1-68 IJI 61-80 1-66 2-84 1-60 0-56 Speaking generally, the proportions of nitrogen, sulphur and chlorine in boiler soot increase with the height of the deposit in the chimney, whereas in the case of domestic soot there is a decrease in these constituents. The value of soot as a fertiliser depends partly upon its physical action in causing a grc-ater absorption (by reason of its dark colour) of the sun's rays, and thus raising the temperature of the soil. It also helps to lighten heavy soils, while the presence of the sulphin- accounts for its action in preventing the approach of slugs. Its nianurial value depends upon the small proportion of ammonia or aimnonium salts which it has absorbed from the volatile gases in the chimney. Taking the value of nitrogen in fertilisers as about twelve shillings per unit, or sixpence per lb., the value of domestic soot may vary from about _'4s. to £5 per ton, since the nitrogen in such soot ranges from about two to eight per cent. The usual price paid for soot is £2 to £i, so that the customer may or may not be purchasing cheaply. Although it is not possible to determine the proportion of nitrogen by any simple method, it has been found that the more springy and bulky the soot, the greater the proportion of nitrogen, and consequently the nianurial value. .\ good domestic soot ought not to weigh more than twenty-eight lbs. to the bushel, and it is recommended that the pur- chaser should stipulate that the consignment shall contain at least four bushels per hundredweight. With regard to the loss of coal carbon as soot, experiments made by various chemists have shown that this amounts to at least six per cent, of the weight of the coal in domestic fires, and to about five per cent, in factory furnaces. On this basis, the annual minimum loss of coal in the form of soot in the I'nitcd Kingdom is estimated to be two million four hundred and twenty thousand tons. Tlie proportion of soot deposited over a given area may be estimated by determining the solid impurities deposited after a tall of snow, and by a determination of the solid matter carried down by the rain. I--xperimcnts made in both ways have shown that the average deposit of soot o\er the whole of Leeds corresponds to at least two hundred and twenty tons per sfjuare mile in a year. GEOLOGY. By G. W'. TvKKiii.i.. A.K.C.Sc, F.G.S. ORIGIN OF RADIOLARIAN CHERT.— Many radiolaiian cherts have hitherto been regarded as of deep-sea origin. Their exceeding fineness of giain, freedom from terrigenous material, and the abundance of their characteristic organisms has led to their identification as fossil representatives of sediments similar to the radiolarian oozes of the present ocean depths. Many observers, however, have pointed out that radiolarian cherts are frequently associated with shallow-water deposits. Their freedom from any but the very finest terrigenous material has milit.ited against the view that the cherts themselves are of shallow-water origin. Mr. F. F. L. Dixon, in discussing the radiolarian cherts of the Carboniferous Limestone of Gower. Glamorganshire iOJ.G.S., Fi:HKr.\KV, 101 _'. Kxo\\i.i:nr,K. November, 19111, gets over this difiiciilty by concluding that their deposition took place, alonj; with other fine- grained deposits, in still and semi-isolated lagoon waters. Four lagoon or .Uorfio/uis. The snniiii-st stations wiTr Maichmont, Cot-klc I'arU and W'fvinoiilh. each with a daily average of 1-5 hours, but at several stations the sunshine record for the week was nil. At Westminster the daily average was 0-4 hours (5%). The temperature of the sea water was very Kenerally above the average, and the means varied from 42°'0 at Hurninonth to 50" -1 at Salcombe. The week ended January 13th was luisettled. with much snow and sleet in the more northern parts of the country. Temperature was lower than of late, but was still ,-ibovc the average of twenty-five years, except in fuiKland. N.Ii.. where it was normal. The highest of the maxima did not exceed 54 , which was reported at a number of stations in difTercnt parts of the country, including stations as far north as StrathpcfTer. Frost was experienced in all districts except the English Channel. In Scotland, R.. minima of 14" were reported at West Linton, and 13" at Balmoral. still lower were observed, down to 10^ at Balmoral, 12" at Buxton and 15" at' Gl.isgow, and Newton Rigg. Rainfall was below the average in Scotland, N., England, S.E..and the I'nglish Channel, but was above it elsewhere. In Ireland the total for the week was more than double the usual amount. There was heavy snow in Scot- land on Monday; at Crieff it was 10 inches deep, and at Cratheswhen melted it yielded 1 ■ 78 inches of rain. Sunshine was deficient in \ ^^ r r r- Figure 71 the Eastern districts, but was C. PeHihecbof ilie in excess in most of the Western districts. The daily average for the district varied from 0-8 hours (10%) in the Midlands and England, S.E., to 1-8 hours (23%) in Ireland, S. Dublin was the sunniest station, with a daily average of 2-1 hours (28%). .'^t Westminster the average was 0-6 hours (8%). The temperature of the sea water was above the average at most places. The mean values varied from 40-2 at Scarborough to 49 -"O at Scilly. MICROSCOPY. conducted xvith the assistance of the fotlowin^ iiiicroscopists : — Arthur C. Bankield. Arthur Eari./ind, F.R.M.S. The Rev. E. W. Hi.wri.i. Richard T. Lewis, F.R.M.S. Iamrs Burton. Chas F. Rousselet, F.R.M.S Chari.rs H. CAfFv.v. a I.ScoiRiiKiD, F.R.M.S. C. D. .Soak, F.L.S., F.R.M.S. THE SELBORNE SOCIETY'S CONVERSAZIONE.— The number of microscopes shown at the .-\nnual Conversa- ziones of the Sclborne Society is larger, perhaps, than at anv other meeting nowadays in London. The next displav will be on February 16th. in the offices of the Civil Service Commission, Burlington Gardens, New Bond Street, W., and any iiiicroscopists who would like to exhibit are requested to communicate with the Secretary of the Selborne Society, at 42. Bloomsbury Square, W.C. SOOTY FUNGUS ON LEAVES AND ORANGES.— It must often have been noticed that towards autumn the upper sides of the leaves of many trees and shrubs become covered with a soot-likc deposit. No doubt this is usuallv looked upon as merely dirt and dust which has collected on them during the summer. The commoner (jualities of oranges fre- quently show the same thing, it being particularly evident near the place to which the flower was attached. Of course there is some dirt present in each case, but the appearance is generally largely due to a fungus growing upon the surface. If the leaf is .illowed to dry slightly, the coating may be detached in flakes by carefully inserting the point of a knife under it. Some of the thinnest pieces should be soaked in spirit and M>c of Ca/:„ water, to which a little glycerine may be added after some hours. On examination under the microscnpe it will be found that the object has the appearance repre- sented in Figure 71, A. It is the mycelium of a fungus not parasitic on the leaf, but obtaining its nourishment from honeydew secreted by the green flies (aphides) so plentiful in some seasons, and which falls on the upper surface of the leaves of the lower branches. There is very little information on the subject accessible to the ordinary microscopist, but the fungus is mentioned and a figure given in Dr. M. C. Cooke's "Fungoid Pests of Cultivated Plants." as Fuinago vagans (Pers). He says: — "This black mould is familiar enough, as it occurs on the foliage of numerous trees in this countr\', and especially such as are subject to honeydew. It forms black patches on the leaves to such an extent as to form a crust ; but in this condition it is simply an imperfect fungus, and may develop into a species of Capnodiitm or Meliola, as the case may be." The specimens occurring on the orange may be treated in the same manner as the others, and it is usually e.mv tn nht.iin ll:il,i>; siirticifntlv large and thin for convenient examination if the fruit is some- what shrivelled. Such a flake is represented in Figure 7 1 . B. It will be noticed that the mycel- ium difters from that of the /•'ji;H<7j5o.beinglessmoniliform and more filamentous in char- acter, though there is much \ariety in various examples of both. In some cases a more advanced stage is present and perithecia may be found in con- siderable numbers. (Figure 71. C.I These areerect bodies, slightly thicker in the middle, almost like narrow tall bottles sometimes branched, compos- ed of threads of mycelium arranged side by side frequenth' with a spiral twist which is only evident under a high power. .At the top the threads are separated and form a fringe round the mouth i fimbriated), while others spring from the sides and base forming a kind of imder.growth, among which the perithecia are situated. These filaments are much more thread-like than those composing the body of the plant, the cells are longer, lighter in colour, with the divisions between them far less distinct. Dr. Cooke says "genuine spon'dia have never been found " but " minute sporules or conidia have been met with." These latter are plentiful near the specimens represented at Figure C, but are too small to be visible under the same magnifica- tion. The fungus also occurs on the leaves of orange and lemon frees in Europe, the I'nited States, and •Australia, frequently in sufficient amount to cause much damage. When present on the upper surface it must prevent the proper action of light on the chlorophyll, and when on both sides, as it is sometimes in the mango ^Mangi/eiti indica). it clogs the stomata and checks transpiration in addition. There is considerable uncertainty as to the life- history, and consc(|uently correct classification of the varieties, but apparently when mycelium only is present and of the character represented at .-V, the fungus is looked upon as a Meliola. while when there are perithecia. with mycelium, as at B and C. some species of Capiiodinni is indicated. What is clear is, that all depend for their development upon the presence of honeydew or the excrement of aphides, scale insects, and so on, and that, though nut directly parasitic, they cause much loss by hindering the vita! functions of the plants on which they occur. The pretty little white four-winged "snowy fly" iAleyrodcs'^. closely related to the scale insects, which sometimes appe.irs in vast <|uantities on cabbage plants as to constitute a pest, is often followed by an attack of sooty fungus. The figures are drawn from specimens mounted in glycerine jelly. That at A is from a leaf of Hedge Maple X210: B and C .ire from an or.ange. BX210,CX40. , ,,,.^.r„^._ Febri'ary. 1')12. ;\"(nvLi:i>G]: row FOWF.R PH()TO-MU'R(H",K.\l'l-n I-OR NArrKALlSTS. I'ART II. lluUKfc, 71. FlGUKi I'lGURE 74. The naturalist is frecjuently interested in photographing his subjects about three or four times life-size, and wishes to secure results with the niininiuni exposure, so that the movement of the object may not spoil the picture. In this connection he will naturally sceU the iiuickest plate, largest lens aperture. and most effective lighting scheme. With regard to the last-named factor, much depends on being able to place and liokl the object in good bright daylight. This brings us to the imperative need of a portable stand. Figure 72 shows us a quite practical stand, made by turning an old pacUitig case — a Covent Garden flower box. to be precise — mouth downwards, and fi.xing inside each corner a broomstick, by means of long screws from the outside, to serve as legs for the table. Next we take three round (penny) blind laths and get a flat side, by a stroke or t-.vo of a jack plane, to each lath. Two of them. B and C, (Figure 73), are fi.xed by one screw each to the back side of the table top, the third. A, to the centre of one end. •-^VUi FiGfKE 7o. The screw is just tight enough to enable the lath to turn on it as an axis, with the flat side of the rod against the box sides. The two laths at the back of the box are designed to support the card or paper backgrounds, while that at the end supports a white card reflector, vide 1-igure 74, where D, the background paper, is fixed by drawing pins to C and U. and E, the reflecting card (non- shiny), rests against A. When the table is not in use it is safer to turn these three laths down, as we see .■\ turned down in Figure 7.1 For working in a room with a quite level floor one may use a four-legged stand, e.g., Figure 73 ; but with an uneven floor or when working out doors, it will be found better to rely on a three- legged stand such as is shown in Figures 72 and 74. In this case the legs should be of two-inch by one-inch quartering or something of that kind that is con- siderably heavier than broomsticks The height of the table may 'conveniently be adjusted so that when the camera is on tile tripod for use when one is 7^ FicuuE 76. 78 KN()\\i,i:i)(".i': February, 191. standing at one's work tlio t-ainora base board is about on a level willi the table top. For backgrounds with this stand it is convenient to fix a sheet of card to the two back supports B and C with drawing pins, and then attach a piece of coloured paper to this card by spring paper-clips of the bulldog or similar type. One requires white, light and d.irk grey and black backgrounds. This, like crayon paper, should not ha\e a shiny surface. In inunediate connection with this form of portable stand is the (piestion of holding such objects as botanical specimens where it is required to photograph, let us say, a small brancli in the position or angle it grows in nature. One of the most useful tools is the familiar " universal holder " found in every chemical laboratory (see Figure 75). The cork-lined hinged jaws of the sliding piece .\H are adjusted by means of the screw at A to hold the specimen. B is another screw to hold the rounded end of AB. The joint at C is regulated by a third screw here, while D is another screw for holding a rod-like part sliding in the socket. There are, however, many homely expedients of a simpler and cheaper character worthy of mention. Turning to Figure 76 we have at A a branch end held in wet cotton wool, which is gripped by an ordinary (penny) American spring clothes clip. At B is shown a small piece of sheet lead bent to form a kind of double C with a narrow groove left open at the junction of the two curves. Into this groove we may insert the stem of the specimen and turn the lead strip on edge as shown at C. At D we have a small block of kitchen soap. In this is made a hole with a brad-awl. Into the hole is inserted the petiole of a leaf. The soap is pressed up firmly round this and affords us a firm holder. In Figure 77 we see a very useful thing for the botanist, viz. : a test tube on foot, cost one penny or twopence, according to size. At A is a light specimen held in the mouth of the tube by means of a strip of blotting paper wrapped round the stem end and plugged into the tube. As these tubes are quite light they are easily upset, therefore in all cases it is advisable to weight the base end by means of a strip of sheet lead, C, folded round the glass tube. For a succulent stem, Cj^., wild hyacinth, it is a good plan to push up from the cut end into the stem a tine steel knitting needle and then insert the free end into a block of soap. Figure 76 D. Figure 78 shows us a method of utilising an ordinary funnel stand and spring clip for holding a stem at a certain angle. I'igure 79 shows a very useful and yet simple plan for hold- ing small things like buds, seeds, and so on. This holder is equally useful for the horizontal or verticil camera. .-\n ordinary glass-headed steel pin, one to two inches long, is passed upwards through the cork of a bottle ;ind the pin point used for holding the specimen. When working with the vertical cauura. the background paper is laid on the top of the cork and the pin passed through I'lGlKE 78. it. To prevent misimderstanding. perhaps it should be said here, once for all, that while 1 now show the various holding contrivances, yet when one is actually photographing the specimens one. of cour.se, does not show any part of the holding contrivance, whatever it may be. 1". C. Lambert, M.A., F.U.I'.S. R (JV A I, MIC K O S C O P I C A L S(JC I FT v.- -December 2()th. H. (.. I'liinnier, ICsq., F.K.S., President, in the chair. — Mr. Konsselet described a retlecting microscope, by John Cuthbcrl, >' hich had been presented to the ^ ■( iety by the Committee of the ' ukett Microscopical Club. Mr. Konsselet traced the history of the reflecting microscope from 1672, when Isaac Newton first suggested its con- struction to the Koyal Society, down to 1827-8, when Cuthbert, at the su.ggestion of Dr. Goring, produced the design e.xhibited. Mr. F. Shillington Scales, M.A.. M.B . F.K.M.S.. gave a lecture on "The Photomicrography of the Electrical Reactions of the Heart." He described the principle and construction of the Einthoven string galvanometer, with especial reference to the optical arrange- ments and the methods of photogr'aphing the movements of the wire resulting from the ditTerences in potential set up l)y the heartbeat. He described the methods of connecting the apparatus to a hospital and the various sources of error that needed to be guarded against, and showed many actual photo- micrographs of the movements of the hinnan heart recorded by this method. Photomicrograplis of the movements of the hearts of various animals under the inrtnence of drugs were also shown. Rev. Hilderic Friend, F.L.S., l-.R.M.S., read a paper on "British lubiticidae." The author first gave a brief historical sketch, alluding to the work of Lankester, Beddard and Benham and the various Continental and other authorities, who have in past years written on the Family. .-Xftcr showing the difficulties attending defini- tion, and the value of the setae for the purposes of classification, the author ])roceeded to arrange the British species in two classes: (1) Those genera which are destitute of capilliforin setae, and (2t those which possess tlieni. These two groups are again snbdi\ided, and no fewer than thirty species, besides some sub-species ,ind varieties, are placed on record, of which ten are described for the first tinie, and sixteen have been added by the author during the year. '- ''J- Specially interesting is the discovery of a new genus, named Khyacotlrili(s. containing two species, of which one [R. bicliactiis Friend) is new to science. These two species are as yet known only in Derbyshire. llyoilriliis is now definitely recorded as British with no fewer than five species. A REVOLVING MICROSCOPE TRAV.— As already mentioned, Messrs. \V. Watson & Sons exhibited a new tray at the Public School Science Masters' Exhibition, which is useful when a number of students or others wish to look at an object placed under a microscope. The tray on which the micro- Fkbkuarv. 191: KNOWLEDGE. 79 scope is placed (see Figure 80) is fastened to a pivoted block, which cairics the lamp and travels on " domes of silence." and when it is moved (he lamp move.-; with il and the lighting is not disturbed. Figure 80. .\ new Microscope 'I'lav-. for it to shew any sign of loss of time, or slackness on snddenly reversing the direction of its travel. The entire mechanism of the fine adjustment is contained in a cavity millcdont of the solid phosphor-bronze limb of the instrument, which is so shaped that it can be conveniently lifted by the back without tension or strain being put on to any critical part. The snbstage is focussed by means of a rack and pinion. It has complete centring adjustments and the portion which carries the condenser can be swung aside out of the optic axis. The inclination axis is placed well above (he stage, so that when the instrument is brought to the horizontal position or inclined, the equal distribution of weight on either side of the centre of gravity renders it exceptionally steady and rigid. Throughout this whole series Messrs. Swift have adopted solid ground-in slides and fittings, in place of the sprung fittings which, on account of want of st.ibility and life, they gave up some years ago. THF PHOTO-MICKOGK.\PHlC SOCIETY.— It may interest those who combine the camera and microscope to know that the above recently-formed society is now- established on a firm basis of membership, craftsmanship and enthusiasm. .\t the moment of writing there are nearly fifty members, and ;it each meeting additions arc being made. The meetings arc held on the second Wednesday of each month, at S p.m.. during the winter end of the year, ;.c".. October to .^pril. both inclusive, rhe annual subscription is five shillings, the place of meeting the Gardenia Restaurant, Catherine Street (next door to Drur>- Lane Theatre, on the Strand side). At the September meeting Dr. Rodman gave an able lecture, showing that photo-micrography co\ered a very wide field of work ; that it need not be an expensive hobby; that ordinary photographic and microscopic apparatus could readily be adapted lor the NEW MICROSCOPES. — A new series of five Microscopes has just been brought out by Messrs. James Swift and Son. The instruments are identical, except for the stages, which range from the simplest to the most comprehensive. The first in the series has a plain rectangular stage with spring clips, the second has a vulcanite-covered centring rotating stage, the third, which is shown in Figure SI, is of the ordinary mechanical type, now so very widel>' in use, the vertical movement of which is actuated by a fine rack and pinion, and the horizontal by a steel multi-thread screw. Both movements have verniers which read to one-tenth of a millimetre. The opening in the top plate is so set that it is impossible for the stage to run foul of the condenser. The ne.\t stand in the series is fitted with the firm's "" I. M.S."' Mechanical Stage, which gives thirty millimetres range vertically, and is so designed that the entire surface of a three inches by one inch slip can be systematically examined. This is accomplished by giving the horizontal slisli Mechanic, January ISIli. where a reproduction of Dr. Keid's typical diagram, duly drawn to scale, may also be seen. At the next meeting, on February Htli. Mr. .\. K. Smith will deal with stereoscopic work with camera and microscope. (The precise title has not yet been announced.) .\nyone interested in photomicrography should place himself in com- munication with the honorary secretary. Mr. J. (i. Bradbury. 1, Hogarth Hill, Finchley Koad. Hendon, N.W. It may, perhaps, be of interest to state that the Society owes its origination to one of the contributors to the pages of this journal, vi^., the Kev. F. C. Lambert, M.A., I'.R.I'.S.. who has been elected the first president of the new society, which has our congratulations and good wishes. ORNITHOLOGV- By Hugh Boyd Watt. M.B.O.L'. BIRDS NESTING I.N ENGLAND IN DECEMBER.— Mr. H. H. W'ardle reports that a brood of young thrushes, fully fledged, was found near Runcorn, Cheshire, on Dec- ember 2()th. 1 y 1 1 . He remarks that December broods are not of rare occurrence and gives the following instances (collected from various sources) for the winter of 1908-9 (a mild and open season) : — Dec. 1. — Sparrow, ycjung. newly-hatched- Tunbridgc Wells. .. U. — Starling, four eggs, Standon. ,, 12. — Starling, yoimg fledged, Cark-in-C"artnnl. L;inca- shire. ., 20, — Robin, three eggs, near Mansfield. ,, 22. — Thrush, four young, near Devizes. ,, 22. — 1 hrush, two eggs, near I,ancaster. ,, 22. — Starling, young about to fly, Chester-le- Street. „ 24. — Starling, three young, fully fledged, near Wigton. ., 24. — Robin, three eggs. Brooklands. Cheshire. ,. 29. — Starling, young, half-fledged, Stockbridge. ., 29. — Starling, three eggs, Stainmore Fells. Jan. 3. — Robin, three eggs, Overton, Hants. ,. 5. — Thrush, four eggs, Ouarry Bank, Market Drayton. Jan. (third week in). — Moorhen, yoimg birds. Botley, Hants. (The Field, December .JOth, 1911, page 1447.) The frecjuency of the occurrence of the Starling in the above list is further evidence of its adaptability and vigour in pushing to the front. PENGUINS BREEDING.— The nesting of introduced species kept in confinement is, of course, a different thing; but it is interesting to know that a pair of black-footed or Jackass Penguins iSphciiisciis licnicrsiis) hatched out two young in the Zoological Gardens, London, in November last. These birds are winter breeders in a wild state, nesting on islands off the Cape in May and June, with which months our winter, of course, corresponds. When they nest in the " Aio " Iti our spring or summer months their eggs are rarely fertile, but they generally succeed in hatching and rearing their young when they nest in autumn or winter, as in the case tmder notice. Birds from the Southern Hemisphere, unless con- forming to our seasons here, fail generally in their nesting edforts. — (D. Seth-Smith. The Fiehl. November 2.=)th. 1911. page 1176.1 FURTHER Ni:W BKHISII BIRDS.— This month one new species and a sub-species are chninicled, and also another species which has been hitherto included in the British list only on the strength of one record and not accepted as unim- peachable. The new records are : — PiNi: BlNTlSG (Eniberiza Icucocephala) \\ F.mk Isi.i..— Mr. Wm. Eagle Clarke received a male bird in full winter pimnage, taken at Fair Isle, on October JOth last, amongst a rush of winter migrants. It is a native of Siberia, wintering in North China. Mongolia. Turkestan and the Himalayas, and is Fe" Fe Cyi;). In some instances, it has been found advantageous to print through the paper, in which case the object being copied must be placed in its proper j , jj aspect with regard to left I and right, otherwise the * inint will be reversed. J si'Ri:ading of I r H I-; I M A GEO F I FIN1-: LINES. — Any- 1. one who has done much * work in the photograph- f ing of fine lines, or struc- '1 tures of that kind, nmst i have noticed the general ■ thickening - up which it takes place, rendering $ the image coarser and i unlike the original in .ippearance. This is well ^ shown in the accompany- i" ing illustrations, which » are photo - micrographs enlarged sixty diameters. :i; ,s.;. In F'igure 82 a we have the enlarged image of two fine lines separated by a distance of js millimetre (i;io in.), and in Figure 82 b an image of the same two lines from a negative that had received double the exposure of a. It will be seen that not only has the space between almost entirely disappeared by the prolonged exposure, but that the spreading has extended to the outer edges as well, to such an extent that the total increase in the width of /; as compared with a is nearly three millimetres in the enlarged image. In two other photographs on the same plate, in which the exposures had been further increased by doubling each time, the separation between the lines had become quite clo.scd up and still further spreading occurred, so that two fine lines had become one thick one. It may be argued that this case SI KN<)\\I.i:i)C.I rilHKfAKV. I'll. is exceptional, since lines separated by «,',o in. cannot l)i' resolved by the luLiidcd eye. bnt tin- (cndcMicy to close up is always (ircsont .iiul selecting soniclliinj; with vi-ry small distances apart tends to show more clearly the phi-noincnon. It is also found that the spreading varies with iliU'iTi'iil plates; in one instance the vari.ition ln'tween a collndiim plate and the same imaue taken on a (jdatirie one, ainonnled to .i ditlcr- ence of ,',, millimetre in favour of the collodion even althonK'h this h.ad been intensified. In I'l^ure 83 is shown the result of doubling the exposure in taking the photo-mierof;raph. from which it will be seen that tlie lines are tendiuK to become thinner, due to the extra len^'th of exposure (jiven in the taking' of the pliolo-micro.irraphs. These examples should be of interest as illustrating the Rreat care necessary in photo- sraphinj; subjects of this nature. rRlNTINC WITH S.M.TS Ol' CIIKOMUM. riH' fdUowini; printing process, due tn the inveslif^ation of Robert Hunt, and announced by him in 184J. imder the name of ■■ Chromatype." deserves attention owinj; to its simplicity together with tlie good results obtainable by its means. Well-sized paper is washed over with a solution of cojiper sulphate, and when dry coated with a fairly strong solution of potassium bichromate. The paper when dry may lie kept for a short time ready for use. In order to employ this paper, it is pLaced with the object or objects upon it, in a printing frame and the whole exposed to light for a sufficient length of time to render the paper almost white, when a yellow positive on a white ground results. On removal from the printing frame the paper is floated upon a solution of silver nitrate when the parts that have been unacted upon by light at once assnme a dark purple-red colour from the formation of silver bichromate. To fix the images the prints are well washed in distilled water free from chlorides, as these latter have a destructive action, even when present in small ([uantity. Prints produced by this method appear to be stable, not undergoing any change when exposed to strong light for a considerable time. EXPOSURE TABLE FOR FEHRLWKY.— The calcula- tions are made on the actino^raph for plates of speed 200 H and D, the subject a near one and lens aperture F16. Dav of Condition of the Light. Time of Day. the Month. 11 a.m. to 1 p.m. 10 and 2 3 p.m. Remarks. Feb. 1st Bright Dull ■25 sec. ■5 ., i - ' If the sub- ject be a general open landscape take half the exposures given here. l->b.l5th Bright Dull 2 sec. •4 ,, ■25 sec. ■5 ., 1 SfC. ■8 ,, Feb. 29th Bright Dull 15 sec. ■3 ,, 2 sec. ■4 „ ■3 sec. ■6 ,, PRINTING WITH COB.-\LT O.XALATE.— This process, originally devised by Messrs. Lnmiere, is capable of giving very fine results. Unfortunately, perhaps, a certain amount of skill in chemical manipulation is necessary to carry it out successfully. It is based upon the action of light in reducing cobaltic oxalate to cobaltous. and this on suitable treatment is made to yield an image finally in sulphide of cobalt. In our first experiments cobaltous hydrate was suspended iu water, through which a current of chlorine was passed, until a black precipitate of cobaltic hydrate was formed, and to ensme the action being complete caustic soda was also present in the water as well. The black precipitate was then carefully washed and dissolved in a calculated quantity of o.xalic acid, it being of importance not to have an excess of acid. The formation of the oxalate should be gradual, and the operation allowed to go on in darkness. The dark green solution of cobaltic oxalate was then employed to sensitize gelatine-coated paper, which must be used as soon as dry. The printing under a negative is fairly rapid, the colour of the paper changing over the parts exposed to light to a pale rose tint, due to the formation of cobaltous oxalate. The prints on removal from the printing frame are treated with a 5 % solution of potassium ferricyanide. which deepens their colour; they are then washed in running water for about thirty minutes, after which they are placed iu a dilute solution of annnonium sulphide for times varying with the coloin' desired. A short immersion gives a sepia, .'i prolonged one black. .\ fin.d washing completes the operations. .\ simplified method of preparation of the oxalate consists in treating cobalt sulphate with soda peroxide (Naj Oi), adding the latter gradually and keeping the solution well cooled to prevent decomposition. The precipitate is then well washed to free it from soda sulphate, and dissolved in a calculated ((uantity of nxalic acid .-is before. PHYSICS. By Al.iKi :l> C. G. Egerton, B.Sc. SIL1C.\. — Fused silica is now used largely in place of glass and porcelain for vessels which have to stand heat without risk of cracking. It possesses an exceedingly small coefficient of expansion. Conse(|ucntly. when suddenly heated the mechanical forces set up in the material owing to the expansion are not great enough to cause cracking, as in the case of similar bad-conducting substances with large coefficient of expansion — such as glass or porcelain. It is eminently suitable as the material for a primary standard of length. It is cheaper than platinum or iridio-platinum, and is not so greatly affected by change of temperature as silica. It has a coefficient of expansion seventeen times less than that of platinum. Invar, the nickel iron alloy, which possesses a smaller coefficient of expansion than any other metal, is not so suitable a material as silica for a standard of length. Dr. (;. Kaye has prepared a standard metre from silica. It cnn- sists of a tube of silica with slabs of the same material fu.sed into its ends. The slabs are optically worked planes, and platinised on the underside ; the platinum film is then ruled with a diamond so as to give the defining lines between which the standard length is measured. It will be remembered th.at the standard metre is the distance between two marks on a bar of platinum which is preserved at the International Bureau of Metric Standards, Saint Cloud, near Paris. It was originally made to be as nearly as possible equal to one ten-millionth of a quadrant of the earth from equator to pole. However, it is now known that the length of the standard metre is not exactly the ten-millionth of the earth's quadrant, but this latter is equal to 10,001.472 metres. .Mthough the standard metre, and, in fact, any such arbitrary standard that is based on the length of a certain piece of metal, might alter in the course of ages owing to certain cosmic changes, yet they can always be checked against the lengths of certain waves of light. Different elements give out light of different wave lengths ; each element has its own characteristic spectrum. One can choose some special element and then choose some special wave-length of light, given out by that metal and find how many such wave-lengths make the standard metre ; thus the standard of length can be expressed in terms of the wave-length of a certain line in the spectrum of a certain metal. This has been done by Professor .Michelson. for the red line given by the metal cadmium. The manuf.-icturers of vessels of fused silica have so perfected their processes that the most complicated apparatus can now be obtained, and it is an economy to buy apparatus which is to be subjected to sudden changes of temperature made of silica rather than glass or porcelain. Silica is not attacked by acids, with the exception of hydrofluoric acid. It melts at about 1,600" C. It is harder than ordinary glass, .\bove 1 ,000" it is permeable to hydrogen. It is also readily permeable to helium, and recently Professor O. W. Richardson has shown that neon can penetrate through the walls of a tube made of silica, though less easily than helium. It expands regularly up to nearly 1 ,000' C, and is exceedingly well suited for making high temperature mercury thermometers, which register tem- peratures up to 700° C, the mercury being under pressure. Owing to its small coefficient of expansion, silica is a convenient Fl.HKLARV. 191. KNOW Li;i)Gl material of which to make a specific gravity bottle, or pyknometer. A pykiiometer is a small tube drawn out to a tube of fine bore at each end ; one of these fine tubes is bent round so as to form a U tube, with the tube of larfjer bore as one of the limbs of the U. The apparatus is weighed, full of water np to a certain mark on the small tubes, and also full of a li(iuid of which it is required to find the density. From the two weighings a measure of the density of the liquid is obtained, pro\ided proper precautions are taken for observing the temperature. When using a glass pyknometer it is often necessary to take account of the expansion of the glass itself, but with a silica pyknometer this is not necessary ; while the latter are much easier to clean and dry, because they can be heated strongly without fear of cracking. Silica is an excellent insulating material for electrical instru- ments. Glass adsorbes water on its surface ; this water dissolves the silicates of the glass, and forms a conducting layer on the surface of the glass ; unless \ery dry glass is a poor conductor, but silica has not got this defect. Professor Strutt some years ago constructed a tube of silica in which to measure the electrical conductivity of mercury at high temperatures. The quartz tube was the shape of an inverted Y. The tube was nearly completely filled with mercury. Wires led into the two limbs of the Y tube, and were sealed in with wax. The junction of the limbs of the Y was strongly heated. .At a red heat the resistance of the mercury was about doubled. Mercury boils under atmospheric pressure at 356" -7 C. By heating it in a closed quartz tube of the above description it was possible to keep it in the liquid form well above this temperature, and thus obtain red-hot mercury. It was not possible, without bursting the tube, to reach the critical point, at which temperature the mercury would go over from the liquid to the gaseous condition, and above which it would not be possible to obtain liquid mercury. It appears, though, from the experiments that the electrical resistance of liquid mercury would be the same as that of the mercury vapour at the critical point. ZOOLOGY. By Professor J. .-Vrthur Thomson. M..A. IS LEFT - H.\NDEDNESS HEREDIT.AKY :- — This question has been recently studied by Professor H. E. Jordan. The cause of left-handedness remains obscure, though it may be regarded as a congenital asymmetry such as is common in organisms. There is much to be said for Sir D. Wilson's con- clusion that left-haudedness is associated with a greater development (preponderant size and weight) of the right cerebral liemisphere. .As we ha\e previously remarked in these Notes, the percentage occurrence in various races is not known with any accuracy. The anatomist Hyrtl puts it at two per cent, among the civilised races of Europe, which is not far oft" what it was long ago among the warriors of the tribe of Benjamin. It is important to distinguish between structural asymmetry (difference in size and weight), and functional iiie/ Chciiiicdl Industry. 1900. See also C:u\ Otlo Wi-ln Kiiiiber ■' ( 1 902), pages 7-11. rii.n.. ■■ riic rheiMisUv of India ' Gladstone and Hibbert ijoiinial of the Clu'iiiicirl Society, 18SS) concluded from an examination of the refractive index of rubber solution that caoutchouc contains three ethylene bonds, and that, therefore, the simplest formula possible for it is tin Hi„. Tluir evidence, however, is not conclusive, owins; to the method of calculating molecular refracti\ ities employed. \IAKCI1. 1912. KNO\VLi:i)GE. Its polymerisation into dipentene (a Indrocarhon present in Russian and A Rubber Tree, Government Plantation. Kiial Lumpur. Swedish turpentine) is shown by tlie CH;i ,XH,+CH,, resemblance to rubber, whereas by "synthetic rubber" is meant a body chemically and physically identical w ith the natural product, though prepared by artificial means. The most important rtibber substitutes are obtained b\' boiling linseed or other oils with sulphur, or acting on them with disui[)hur dichloride, when chemical combination takes place. They are used commercially for mixing with certain low grade rubbers. The synthesis of rubber dixitles itself into two processes, (ji the production of isoprcne. (ii) the polvmerisation of isoprene to caoutchouc. .\s we have already noted, tiie second of these processes takes place spontaneously, but it ma\- be facilitated by means of concentrated hydrochloric acid, or by saturation ot the isoprene with oxygen or ozone. The latter process is as follows* : — The isoprene is saturated with o.wgen or ozone, allowing twenty volumes of oxvgen to one volume of the hvdrocarbon. and spreading the treatment over about six hours. The liquid must be kept cool during the process. It is then placed in an autoclave and heated to 100"C, until it is converted into a viscous mass. The resulting caoutchouc is dried by evaporation, or precipitated by means of alcohol. A solution of isoprene in benzene may be used instead of the pure substance. The heating is not alisoluteh' necessary, though advisable. .■\nother method is to act on the iso])rene with one of the alkali metals, (e-jt,'.. sodium or potassium) or an allo\- of one of these metals. + To turn to the preparation of isoprene. The following method^ is interesting scientificalK", because it is a true s\'nthesis of isoprene. in whicli it is built up from simpler wing equation — CH/ X-CH CH,= 2 molecules C-CH:, CH, soprene. •CH.. CH,^ CH.. X-CH X ~"CHo-CH 1 molecule Dipentene. and it is presumably by some similar, thou cated, reaction (that is, involving mot isoprene) that it is changed into rubber. CH:, more compli- molecules of II. Synthetic Rrr.iuiK. Some of the greatest achievements of chemical science in recent times have been in the direction of the synthesis from inorganic materials of \arious important products of the vegetable and animal world. Since the day in \H2S when Wohler performed the first synthesis of this nature — the preparation of urea from ammonium cyanate — an inmiensc number of animal and vegetable products havi been artificial!}- prepared in the chemical laboratory, amongst which caoutchouc must now be included. Synthetic rubber must not be confused with the various rubber substitutes and imitations of rubber wliicli ha\e from time to time been placed upon the market. Such rubber substitutes and imitations are bodies with merely a superficial Trees, Govcrm Kuala. Lumpur. English Patent, 1910, Xo. 14.041. A. Heiuemann. liiiprovciiiciils relating to the Polymerisation of Isoprene. i English Patent, 1910. No. 24,790. F. K. Matthews and E. H. Strange. Synthetic Caoutchouc. English Patent, 1907, No. 21.772. .\. Ileinemaim. A Process for the Synthetic Production of India-rubber. KNOW Li:nGi: hodics. Acetylene and ethylene are coniliined to form divinyl by heating them together in a tube raised to a dull red heat; and tlie resulting divinyl is converted into the methyl derivative (isoprcne) by the action of methyl chloride, thus: — rH-=CH + CHi^-CHj ^ CH, = CH.CH^CHi, Acetylene. laliylene. Dhiiiyl. His apparatus is shown and described in Figure H9. Mr. Hcinemann, whose patents we have alreadv referred to, finds that the yield of isoprene may also be very considerably improved by passing the turjientine vapour over finely-divided copper or silver, or, better, by using tubes made of either of these metals. The temiierature must be ke|)t low. Figure 89. Dr. O. Silbcrrad's Isoprene Apparatus. The .ipp.ir.mi5 consists of a licalin;; coil a, inside a hciling cliamber /', licalcil by tlie prod ucls of combustion from a number of iras Imrncrsr, electric pryromelers, .i, .i, lienij; provided to determine llie lemper.lllirc. From the heating coil, a pipe .• leads to a water-cooling coil / situated in a water chamber jr. The hydpicarhons coiidenscil in the coil / p.xss into a vessel h, and the uncondeiised vapours pass through a pipe k, provided with a inercury-gau-^e /, into another condensing chamber /«, from which further hydrocarbons arc collected in the vessel «. The vacuum is produced by means of the vacuum and com|>ressing pump o, and the vapours pa.ssing the pump p.a.vs through a cooling coil /, immersed in brine contained in the chamber l. Isoprene is condensed in the coil /, and is collected in the chamber r. From the chamlier r, the uncoiidelised vapour passes by the pipe s to the chamber /, immersed in the brine contained in the vessel u. A blow-ofT valve v is provided from the top of this last condensing chamber. CH.. = ClI. C II + CH, CI CH, Methyl chloride. Mcthvi diyiml or Isopreiu + HCl The methods of producing isoprene from coniinon substances of a more complex nature, whilst not exactly syntheses of this substance, arc, however, of more importance commercially. It was some time ago that Sir William Tiiden discovered that isoprene could be obtainet-i In- passing turpentine through an iron tube heated to a dull red heat : hut the yield was very small, being only about six per cent. Dr. Silberrad" finds that the yield is very greatly increased if the turpentine is heated under such conditions that the vapour is produced in a highly rarefied condition. about 450''C. in the case of silver, or JO°C. higher ill the case of copper, otherwise the isoprene is converted largely into dipentene.^ The latter chemist has also patented a very interesting method of con\-erting carbohydrates, such as cane sugar, starch or cellulose (sawdust) into isoprene*, as follows: — The carbohydrate is first converted into laevulinic acid by boiling with dilute hydrochloric acid. To this substance are added one and a half parts of phosi)horus trisulphide, and the mixture heated in a retort to 130"-150"C. A violent reaction takes place, and thiotoleiie (CH., — C4 Hg — S) is produced, thus, — ,CH,-CH, PS,, CH-CH CH„-CO CO.OH ^ CH.t-C ill Laevulinic acid ^S Ihiotolene English Patent, 1910, No. 4.(K)1. (). Silberi;id. I'h.I).. I in/iiovciiu-iits in the M.inii/dctiirc of l^opniic. Our thanks are dne to Dr. Silberrad for a photograph and particulars of his apparatus not given in the Kiiglish Patent Specilication. I English Patent, 1910, No. 14,040. A. Heineniann, Improvements relating to flic Production of Isoprene. I ICiiglisli P.itcnt, 1908, No. 13,252. .\. Heineniann, . I Process for Coni'crtinii Ciirboliydrittcs into Hydrocarbons. M\K(il. I'M 2. KNO\VLi:i)(~.I' Phosphorus pentasulphide may be used in place of the trisulphide, in which case thiotenol CH'' — CH is obtained instead of thiotolene. CH:,-C C.OH The thiotolene or thiotenol is con\erted into iso|)rene by reduction with liydrogen, effected b\- passins,' a mixture ol citlur compound with lu'drof^en over finely-di\'idcd copper or iron at a temperature of 300°-50{l". CH--CH CH., CH,,-C 2H, = CH.-C + H.,S CH-CH, The ring breaks at the point indicated, the sulphur lirst combines with the metal, and the resulting sulphide is then reduced by the hydrogen, giving sulphuretted hxdrogen, the above ecpiation showing the final state of affairs. Aljove 50()~(" the iso[5rene is con\-erted into dipentene. Drs. W. H. Perkin and C. \\"ei/maim ha\e patented ' a process for iirejjaring isoprcne from amyl alcohol. Two parts of the latter are allowed to stand with one part of zinc chloride for twent\'- four hours and then distilled. This process eliminates the elements of water from the amyl alcohol, and the resulting amylene is converted into isoprene by passing through a heated tube. Thus : — C,,H„. OH - H,0 = C.-,H,o = C,-,H, + H-, .\iiiyl ;ilc()h()l. Amylone. Isopreiic. .V good deal of work is still being expended on the problem of the inexpensive production of caoutchouc by artificial means, and further results may soon be expected. As to whether the synthetic article will ever prove a dangerous rival to natural rubber it is not possible to say.t Doubtless, in course of time, increasing numbers of natural products will be replaced b}- substances identical in all their properties but chemically prepared ; — doubtless, also, sj'nthetic caoutchouc (which at present is in its merest infancy) has a future before it and will one day play a part in hel[)ing to meet the alread\- enormous and rajiidly increasing demand for india-rubber, lint there is no cause for fear of aiU' decay in tlu' rubber-growing industr\' on this ;iccount. ' U. S. Patent. No. 991,453. W. H. I'crkin and C. Weizmann, Process of Manufacttirin^ Isoprcne. In Ibis connexion we must bear in mind that it is not without the region of possibiHty that natural rubber may owe some of its vahiable properties to the intimate mixture with the caoutchouc of the small quantity of other substances present. Tests to settle this <|Ucstion and to determine whether the synthetic, chemically-pure caoutchouc (as obtainable at present) is really physically identical in all respects with the natural article, do not appear to have been carried out. SOLAR I)lSTrRF,.\\XES DURING JANU.ARY, 1Q12. I'.v FRANK C. DENNETT. .Adverse weather has much hindered Solar study during the past month. At the same time the Sun has preserved a con- dition of almost unruffled quietude to the telescopic observer. Only on one day. January 5th, some faculic flecks showed near the limb in the south-eastern quadrant, and so not far from longitude 25° to 35°. They looked like the renmants of an out- break. As the exact position was not measured it is impossible to present the usual diagram this month. The progress of the cycle of solar phenomena is best shown by the table of observations during the past eleven years. It gives the number of days on which the Sun was observed, also the number when spots were seen or taeniae only, and those when there has appeared to be a clear disc. Year Observations. Spots. Faculae only. Cleai 1901 251 49 — — 19n2 270 .. 56 35 179 1903 33S .. . 280 43 15 1 904 331 . 329 2 0 1905 ... 345 .• 343 2 0 1906 351 . 346 5 0 1907 350 . 350 0 0 1908 343 . 337 5 1 1909 342 . 340 2 0 1910 343 . 278 48 17 1911 ... ill .. . 155 ... 90 ... 87 The consideration of these figures lead to the expectation that the time of minimum will occur at the end of the present year or early in 1913. The decrease of activity was earliest noted in the northern hemisphere, and therefore the earliest return may naturally be expected there. The eclipses of the Sun on April 17th and October 10th. should be of special interest, as, occurring at a time of minimum, the corona may be expected to present what is known as a winged appearance. The poles of the Sun are marked by short sharp plumed rays, whilst the coronal matter is extended into elongated streamers in the equatorial regions. It would appear probable the winged circles which figure so largely in Egyptian temples, and so on, were designed from such a phenomenon. The corona usually seen at the time of maxinunn,asin 1905, is quite different, the polar plumes being absent, and the coronal rays appearing to radiate in all directions instead of being confined to the etjuatorial regions. Another feature noticeable at the time of mininunn is that the prominences are fewer in number, and many forms which are of frequent occurrence in times of activity are almost if not entirely absent. Helium may always be observed in the chromosphere as a bright orange line known as Dh. Frequently it may al.'io be observed as a dark line amid spot groups, and over faculae. During 1909, 1910, and 191 1 the observers who co-operate in producing this monthly report have recorded the presence of this dark Hue on 112, 85 and ii times respectively, decreasing with the decrease of activity. The observers who contributed the material for the present page were Messrs. J. McHarg, A. A. Buss, E. E. Peacock, \V. H. Izzard, and the writer, at widely scattered stations, yet they only succeeded in seeing the Sun on twenty-one days throughout the entire month. Errata.— In the February number, page 59 in the 5th and 3rd lines from the bottom read 28° instead of 38°. Till' I'ACI- ()!•■ rill-: SK\- l-OK Al'KlI.. J^^ -^^ '• !>• t'KoMMII.IN. i;..\., D.Sc, I'.R.A.S. .1 Mars. Jupiler. Saturn. Uranus. Neptune. U.A. N. ilrr. K..\ li.M-. 1 K.A. N.Dtc. R.A. S.Dec. R.A. N.Dec. K.A. S.Dec. R.A. N.Dec. N Apr x*h il . 1 5 h. m. 0 56 -S 1 14-8 <'i 60 h. in. , 11 34 7 N. 5-6 IS 44M S.23-1 h. m. 1 41-1 1 460 137 M-4 h. m. 33 7-3 .S.7-I 33 30-3 84-8 h. m. « 5 48-3 35-, h. m. 10 57-0 3r9 16 56-9 31-8 h. m. , 3 4-7 15-3 h. ni. 30 31-8 30-0 h. m. 7 30-4 "i lo 79 30 11-9 S.J5-4 0 64 ,S. 1-3 4 as'5 N.J5-6 9 35 3 N.19-3 1344-8 .S.il-5 I 41-2 .3-6 33 53-9 S.3-4 6 13-0 35-3 1656-4 31-8 3 9-3 15-6 30 33*3 30*0 7 303 31-3 l.t ■ ■ 1' sM ■ 30 4 0 15-4 o-o t> 34-3 35-1 16 55-7 31-8 3n 93*7 30*0 I 10} 90 038-0 N3-4 1654-6 21-8 ■'I ^I'l 30'0 7 30-8 31-3 I 13-7 69 I CIS N.4-8 6 48 7 347 3 :6-6 ■>o'o I I2'9 57 ■ 33-3 N.7-3 71-1 34 4 i« 515 31-7 3 19-2 30-0 7 314 31.3 Table 9. D.-iie. P (»reenwich Noon. ^ M.-irch ;i -36-3 April 5 36-4 ,, 10 36-4 1- >5 36-3 35-8 35 253 30 -34-4 -26'7 —0*8 377-3 35-4 +0-4 239-3 Jupiter. I 33' 48 ;« ' 34' 53-8 85-8 .17-8 3 36c 9 33" Table 10. Greenwich Civil Time (day beginning at midnight) is used throughout these notes: m. e are used to denote morning, evening respectively. P denotes the position angle of the axis of the body measured eastward from the N. Point of the disc. B IS the HeIio-(planeto-)graphical latitude of the centre of the disc. L denotes the longitude of the centre of the disc, and T the ti-Jinsit of the ^ero meridian across the centre of the disc. In the case of Jupiter, Svstem I of longitude refers to the Equator, System II to the 1 emperate Zones. To find intermediate values of T apply multiples of 24" jgi"", 9" 50*"". 9'' 55*"". for Mars. Jupiter I. Jupiter II respectively. Q, q for Mars are the position angle and amount of the greatest defect of illumination. Tni-; SfN continues its rapid northward march, and by .April 21st has attained half its maximum North Declination. It rises at Greenwich at 5" 38"" on April 1 st, 4" J6"' on .■\pril 30th ; sets at 6* 30" on April 1st, 7*' 18"" on April 30th. The semi- diameter diminishes from 16' 1" to 15' 54". Thk Moon is Full April l*" 10" 5'"t'. L. (). 9" 3" 24"" c New I7M1" 40" m, K.p. 24" 8" 47'" ;n. Full May l" lO" 19'" m. Apogee April 10'' l" w, semi-diameter 14' 48"; Perigee 22 10" e. semi-diameter 16' 12". Greatest libration 5° W April 3", 7°S 9^ 5° E 16", 7° N 23", 5° W 30". The letters indicate the region of the limb (considered with reference to our sky) carried into view by libration. Observers should take advantage of favourable libration for studying the region near the limb. disc eclipsed ; Last contact with shadow ll" 3" c, 235° from \ Pt. to E.. last contact with penumbra Apr. 2" O" 34°" in. The outer part of the penumbra has no visible effect, the inner part produces a smokiness on the disc. This eclipse is visible throughout Europe and Africa, in Western Asia and Eastern America. ANNUr.AR-ToTAL ECLIPSE OF THE SUN, .\PR1I. 17TH. — Details of the central line across Europe of this interesting eclipse were given last month. It is the largest solar eclipse in the British Isles since that of March, 1858, of which it is a return after the triple Saros. That was the third of three annular eclipses in Great Britain at eleven-year intervals. The line where the magnitude is 10 of the Sun's diameter runs from Cape Clear through Tipperary, Greenore, Down- D.iie. Sl.ir's Name. Magnitudes. Disappearance. Reappearance. Mean Time. Angle from N. lo E. Mean Time. Angle from \. to E. 1912. .■\pr. 2 ,. 3 ,, 6 „ 9 ., II >. 21 ,, 21 ,, 21 .. 23 ., 23 ., 23 B-'\G 4.S54 S6 \ irginis .■\nlarcs lUC 6525 BAG 7237 KAC 1S4S l36Taurl HAG 1918 47 nciiiinnruin <">' Cancii w^ Cancii "[ 7-8 5-6 1-3 6-2 6-2 56 46 6-1 56 6-1 6-2 h in 1.27 III 6.26 III 6.57.- 7-5' '• 10.47 ' 0.55 "' 7 ly ii. 5,- 114 46 39 i"5 93 90 ic6 '59 I> .a 943'- 2.40 /« 3. 48 III 4.51 "' 7-34 c- S.47<- 1 1 . 36 « 1 40 III 8.27' 5.49 ' 354° 313 277 242 328 253 275 290 293 241 Tahi.i: 11. Occultations of stars by the Moon visible at Greenwich. Partial Eclipse of Moon, .\pr,,. isT.-First contact with penumbra 7" 55" e ; First contact with shadow 9" 26'" c 183 from N.Pl. to E., MiJ-Eclipse 10" W e, one-sixth of Patrick, Wigtown, Edinburgh, Fifeness. The I'^n line begins at Start Point, and runs just south of Oxford and King's Lynn. The largest eclipse in the British Isles occurs on the coast 90 NfARCH. 101: KNOWLEDGE. 01 from Dungencss to Dover, where i'',-.'., of the Sim's diameter are covered. The smallest occurs in the island of Lewis where the magnitude is r",;-,-,. (It may be mentioned that the central line of the annular eclipse of 1921 crosses Lewis.) The following table gives particulars of the eclipse for various British Stations. The times are in Greenwich time e.\cept for Ireland, where they are in Dublin time. The letters in, e are not inserted, as they can readily be inferred, the eclipse being in the middle of the day. 4" 35"": I. Kc. D. 10'' ll'' 44"' 45" c; I. Oc. R. 11" 2" 58""; I. Tr. K. U" 0" .V" : II. He. D. 14"" l" IS"" 56" ; III. Ec. R. 1.5'' 0" 50"' 57". III. Oc. D. 2*' 58"'. III. Oc. R. 4*' 52'": II. Tr. E. 16'' 0" 5'V"; I. Sh. I. 17'' 4" 15"": I. Ec. D. IS'' 1" iS"" 13", I. Oc. R. 4'' 45"": I. Tr. I. IS"" ll*" 39"'e; I. Sh. E. 19'' 0''57'".l.Tr. E. l" 52"'; I. Oc. R. 19'' ll'' \2"'c; II. Ec. D. 21'' a*" 53"" 26": III. Ec. D. 22'' 3''0"' 17", III. Ec. R. 4" 49'" 39"; II. Sh. I. 22'' lO" 59" c : II. Tr. I. 23' O" 43"'. II. Sh. E. 1" 38", II. Tr. E. 3" 20"'; I. Ec. D. 25' 3"' 31'" 43": .Armagh. Dublin. Gla^ow. Edinburgh. Liverpool. Durham. 0.\ford. Greenwich. Canihridge. First ciHilact loh. 24m. loh. 2{m. loh. 54in. loh. 55m. loh Sim. loh. 55m I oh. jom. loh. 51m. loh. S2m. .Angle from North Point 221° 222° 222° 223° --3° 224° 227° 228° 2. '8° Angle from Vertex .. 240° 242° 238° 237 242° 239° 244° 244° 243° Greatest eclipse nil. 40m. uh. 39m. oh. lom. oh. 1 1 Ml. oh. 9111 oh. 12m. oh. 9m oh. iim. oh. llm. Magnitude 7S9 ■810 7S9 ■800 ■S47 •838 ■899 •920 •906 Last contact oh. S7'n- oil. 58..1. ih. 26m. ih. 2Sm. Ih 27ni. ih. 301H. ill. 29m. ih. Am. ih. 31m. Angle from North Point 66° 6S° 67° 66° 65° 64° 60° S8° 59° Angle from Vertex 55° 53° 54° 52° 46° 47° 41° 39° 40 The angles are measured from North Point or Verte.\ towards the East. The partial eclipse is visible in Eastern .America, throughout Europe. Northern Africa, and Western and Central .Asia. Mercury is fairly well placed as an evening star at the beginning of the month, setting in England about l^ hours after the Sun ; diameter 9", J of disc illimiinated. It is in inferior conjunction on the 15th. It is 3j° West of the Sun during the eclipse on the 17th, but, being such a thin crescent will scarcely be seen. At the end of the month southern observers will see it as a morning star; diameter 10", h of disc illuminated. Venus is still a morning star, better placed for southern observers than in England. Her diameter diminishes from 11" to 10", ^i of the disc are illuminated. She will be some 20" South-west of the Sun during the eclipse, and will doubtless be readily discernible in all places where the eclipse is large. Mars is an evening star. Its disc is becoming too small for useful work. The diameter diminishes from 6" to 5". It is 20' South of f Geminorum on April 21st. Jupiter is now well away from the Sun, and favourably placed for southern observers. The polar diameter increases from 38" to 41". The equatorial is 2f' greater. Defect of illumination 4". The diagram shows the configuration of the four large Satellites at 2'' m, for an inverting telescope. Day. West. East. Day. West. ' East. .•\pr. 1 4 0 ;2 Apr. 16 412 0 3 >. 2 21 0 43 » '7 24 u '3 ,. J 2 0 34 „ 1^ 0 423 '• " 4 01324 .. 19 3" u 24 " 5 31 0 24 ,, 20 .12 0 '4 „ 6 32 0 '4 .. 21 3'2 (J 4 .. 7 3' 0 4 -• .. 22 u 124 „ 8 O3124 .. 2; I 0 34 i •• 9 .J 0 43 .. 24 2 V 134 ' ,. 10 24 0 13 . 25 1 0 2^ ,, >> 4 0 i ■I* „ 26 J 0 42 ., 12 43' 0 2 ,. 27 342 0 f •. '3 4.'2 I „ 28 43 i 0 • . "4 43' 2* .- 29 43 0 12 ,. 15 43 " - 30 41 3 3 i Phenomena visible at Greenwich (all in the morning hours unless marked c) :— I. Ec. D. 2^ 3" 23" 1" ; I. Sh. I. 3'' O" 29". I. Tr. I. 1" 36". I. Sh. E. 2" 42". I. Tr. E. 3" 49": I. Oc. R. 4" 1" 9". III. Sh. I. 4" 49": II. Sh. I. 5" 4" 32"; II. Oc. R. 7'' 3" 31": III. Oc. R. 8" l" 17": I. Ec. D. 9* 5" 16" 26= ; I. Sh. I., lO" 2" 22", I. Tr. I.. 3" 25". I. Sh. E., I. Sh. I. 26'i0'' 37". I. Tr. I. l" 26". I. Sh. E. 2*' 51", I. Tr. E. 3" 38" : I. Oc. R. 27'' O'' 58" ; II. Sh. I. 30" l" ii"'. II. Tr. I. 3" 2", II. Sh. E. 4'' 12". S.\TURN may still be seen as an evening star, but is drawing near the Sun. It is 23° East of the Sun on the 17th. and may be seen on the central line of the eclipse. Uranus is a morning star, still badly placed. Neptune is an evening star, still within the limits of the map given in " Knowledge " for December. Meteors. — The following radiant points are due to Mr. W. F. Denning. Date. Remarks. R.A. 1 Dec. Mar. to May 263° + 62° Rather swift. -Apr. 1 2 to 24 210 _ 10 Slow : firelalls. ,, l6to2j 301 + 23 Swift, streaks. „ 181023 189 — 3' Slow, long. ,, 20. 21 261 4- 16 Swift, bluish white. ,, CO to 22 271 + 33 Conspicuous shower, swift. ,, 20 to 25 21S - 31 Slow, long paths. ,, 30 ... 291 + 59 Rather slow. Apr. — May ^93 + S8 Slow, yellow. -Apr. — May 296 + 0 Swift, streaks. Minima of Algol (period 2'' 20" 49"), every third minimum given. April 1" 11" We, 10" l" 41" c, 19" 4" 8"m, 27" 6" 35"e. Cluste RS AND Nebulae. Name. R.A. Dec. Remarks. w\- 46 I r'' 5" N 36° •2 Large faint nebula. .\I. 97 9 N'55 •6 Oval nebula. 2° .s.f |3 Urs. Maj. W I- 270 I ; N59 ■4 Small bright nebula. 271 I ; N58 ■6 Elongated nebula. M. .,5 60 '5 N 13 ■6 I'aint double ncluila. w •• 194 21 N44 ■2 Large nebula. W' ■73 4,S N37 •6 Large nebula. lil\-. 10 !•> 5 N .9 • 1 Cluster. 4 3 12 14 ■N'47 ■9 Large oval bright nebula. w 1 '>; T2 '9 .S iS •2 Nebula. M. Si 12 20 N iS •8 NcbuLa. M. 02 12 3' N 28 ■5 Nebula. 84 12 46 N 26 •0 Nebula. 64 12 52 N 22 •3 Large liright nebula. KNOWIJ.DC.I.. Double Stars.— The limits of K.A. art- 1 1" to l j" Maucii. 1<)12. ^,.„. Ivi^lu Ascension. Declination. Magnitudes. Angle. N. tu E. Distance. Colours, etc - 1520 h. m. II II N ii'-i (>1. S 344° 13 " White, blue. f Ursne MnJDiis V Ursac Majoris II 1 ; N 3J •■ 4. 5 120 3 \'ellow, '.vhitc. n li N a 6 4. 10 147 Vellow, white, blue. t Leoiiis II II) N 1 1 0 4. 7 49 2 Yellow, blue. 83 I^onis ... 1 I ^2 N 3 -S '', 7 ■51 29 Yellow. 57 Ursac Miijoris 11 24 N 39 -8 j. s 0 5i While violet. 93 Lconis ... I 1 30 X 17 -3 6. 7 21 1 ? While, blue. Anothe st.ir in position. 2 ;4 63 Pi Kl. Ill ... " 32 N 28 -3 6- 7 ,. 351 3 White. I nil magnitude star in position, 14.S 21 Groomb l8oq ■' 34 X 64 -9 6i, 8 321 2 White, ash. - 1579 ■•'• 1 1 50 N 47 'O 6, 8 3S 4 White, blue. 7ih m.ignituck star in position. 114 63 2 Ciiniac- ... 12 0 N 22 -o 6. 7 238 4 White, blur. W. B. (2) .\tl. 56 12 6 X 40 -4 6, 7 334 I White. :; 1639 12 20 N 26 I 6, 8 350 1 White, a.sh. 24 Comae 12 31 N iS 9 5. 6 271 20 \-ell..w, blue. 7 V'irginis •2 .'7 S 1 0 3. 3 325 () \ellow. 35 Comae 12 49 \ 21 -7 5, fi. 9 125 I 1 29 I Triple. 0 Can. Veil. 12 5-' N 58 -S 3. 5 227 20 Yellow. 22 l6q4 12 49 N S3 .9 5. S 327 21 Yellow, blue. i: "695 12 32 X 54 -6 0. 8 2S4 3 White, blue. THE TINTS AND SHADES OF AUTUMN WOODS. By P. g. KKHCxAN. LL.D. iContiiiiicd from pcific 51 What then is the specific cause of the aiituniiial red colouration of the forest leaf? It is undouhtcdl\- produced siinilarly to that of the red petal (see January nimiber of this journal, page 15), the albuminoid molecule is disrupted, but not because there is a violent demand for its nitrogen aiul phosphorous elsewhere {i.e.. in the pistil), as in the case of the floral organ. No, the disruption of autumn ensues because the cell plasm gradually loses its vitality- ; nitrogen becomes deficient, but it is not draw n away, nor is it reproduced /;; loco ; there is a difl'erent chemism because there is a change of nature of the plasm, and so long as it still lives it can do with less nitrogen, the nitrogenous content of forest litter being in all these special cases com- paratively small. Moreover, behold also a most interesting difference ! The physiological processes going on in stamens and pistils in connection with fecundation and reproduction are so vigorous and powerful that special and peculiar tannoid chromo- gens are produced in the petals, which frequently evolve extremely vivid and brilliant pigments. Hut this is not the case with the fading glories of the woodlands. The autumn leaf is far too feeble and exhausted to permit of any such demonstration of energy. The tannoid of its early life is gradually. as tlio suinniir months elapse, converted into tannin, which, moreover, may have a different chemical composition and constitution from that which the flower of the same plant evolves, or nia\' e\-ol\e. Thus, in the petals of Foxglove. and so on, tannoids arc found which are utterly absent in an\' of the otlu-r organs at any period of their existence. On the other hand, where, as in the yellow, brown, and russet lea\"es, the albuminoid becomes insoluble and passive and remains permanently stored up, as it were, there is no special deassimila- tion thereof ; its chemical transformation has ceased, and hence there is no fresh production of tannin and pigment. Hence the brown shades may be regarded as a mere decomposition product, dull and dead, which ultimately impregnates the dry coagulated cell-contents massed against the equally lifeless cell- wall. We have already seen how this phenomenon coincides w ith a high percentage of total ash con- taining a very high percentage of silica : which means that the inert physiological condition has permitted the encroachment of all this encrusting matter more especially upon the epidermal cells, the ver\- spot where under other conditions the brilliant autumn tints are specially evolved. ON THE FAIJXA OF rp:shmi]lance of the Il^EEAND TO THAT OF P1-:X INSULA. FLORA AND THE SPANISH Bv K. 1-. SCHAKl'l'. I'li.l). i-.r..s. Till-: late Edward Forbes long ago drew attention to the remarkable fact that in the south-west and west Figure 90. The Spotted Slug {Geoinalacus inaciilosus) and a Map showing its distribution. of Ireland there exists an assemblage of plants which do not occur elsewhere in the British Islands, although apparently native in the north of Spain. Several writers have subsequentl\- commented on this feature in the Irish flora. Not many plants belong to this " Lusi- tanian element '" in our flora, vet the\' are sufficiently recognisable to have attracted the notice of every observant botanist who has visited Ireland. Since Professor Forbes wrote his well-known essay on this subject,* a few species of plants unnoticed by him have been added to this Lusitanian flora: and what is more remarkable, it has been discovered that there are also a lew animals which possess a similar geographical distribution. This peculiarit\- in the Irish flora and fauna has thus acqinred (piite an exceptional interest anioi naturalists. One of the most conspicuous plants the neighbour- hood of Killarney, in the south-west of Ireland, is the Strawberrv - t ree {Arbutus iiiudoK a bi'antifiil cvir- green busln ti'ee, bearing in the earl y w inter pretty red globu- lar berries, which have given rise to its popular name. FreijuentK rulti- vated in gardens in the south of England, it only grows wild, out- side the Irish boundaries, in the Spanish Pen in- F sula, along the Triclioniscu In land. Sp; vividiis, found in and the Pvrenees. Rliopiilontcsitc FiGLKli yi. tardy i and a Map showing Is distribution. borders of the Mediterranean ami in the extreme south- west of France. A much commoner plant, though less noticea.ble, is the well-known London Pride of English gardens {Saxifniga tniihrosa). Like the last it is only native in Ireland, where it grows in abundance in many of the southern and western counties. On the Continent it is onl\- known from the Spanish Peninsula and the P\renees. .\ closely allied Saxifrage {t>ij.\ifni^i\2. (.Iisti'iliiitii>ii in Inliind. wIuiims iihtniiil it extends somewhat fiirtluT cast than llic otlicrs do, as far as Swit/irland. Two Iji'Miitiftd luatlis inlialiil llic wcstciii |iails of •IGIRF. 93. Large-floweicd Hiittcrwort U^inguicula firaiidiflora). West Cork the counties of Mayo and Galway, and arc found nowhere else in the British Islands. The first of these, known as the Mediterranean Heath (/iV/a? mediterraiica. see Figure 94), with its prett\' flesh-coloured flowers, grows ahund- antl\' in Portugal and the north-west of Spain, while St. Dabeoc's Heath (Dcihcocia polifolia. see Figure 95), with its elegant large pink bells, has the same range, which extends into south-western France. Now among animals, as already remarked, we likewise possess similar instances of species confined to Ireland and the Mediterranean region, or the Spanish Peninsula. Most of these, however, exhibit a less iriarked restric- tion in their range to the western counties. Yet one of the best known examples, the Spotted Slug (Geomctliuiis nuiciilosiis, see Figure 90), has a geographical distribution in Ireland almost identical with that of the Strawberry-tree. On the Continent it is apparently peculiar to northern Spain and Portugal. In Dublin and in the south and west of Ireland a large spider is frequenth' noticed, which seems to replace to some extent tin- common house spider. It has been named Tejiciuirui liibcniica. and is not known from Great Britain, though it is closely related to. and i)erhai)S identical with, the Pxrenean Te<>enariii nervosa. .\mong the wood-lice there are several species belonging to the same Lusitanian group. The claret-coloured Trichoiiisciis vividiis (see Figure 92), for example, occurs only in Spain and the Pyrenees, as well as in tile south of Ireland, i'inally. two s|)eries are confined in Ireland to the Hill of Howth on the cast coast. These are MctdpoiKirtliiis iiiclaiiiinis and liltinui f>iirf>iiriiscL'iis. These are onlv a few of thi; luore note- worthy examples of Lusitrmian plants and animals occurring in Ireland and not in Great Britain or even in the north of France. It is quite evident, therefore, that the Lusitanian element in the Irish flora is more significant than Profes.sor Forbes had imagined. .And yet he argued on the strength of his own observations on the habitat of these plants, that the latter could not have I'tcn conveyed bj' either winds or marine 1 urrents to the stations they now occupy, which opinion has since been generally adopted by Irish botanists. When wc take into con- sideration the presence in Ireland of such a slug as Gcomalactis iiuiciilosiis, which could certainly not have been carried to Ireland by any ^)f the known means of accidental transport, and whose eggs can neither float in sea-water nor be wafted across the ocean from Spain by winds, the problem is not so readilv solved as some recent authorities seem to imagine. It has been L.- i-IGURK y4. The Mfditenaneau Heath Ui^nca nuilitciitiiu March. 191. KXOWLI-.Or,]- suggested, indeed, bv several writers that the Lusitanian element in the Irish flora is due to or- dinary accidental causes, such as winds and ocean currents. When we surve\- the fauna and flora of the British islands as a whole, we find that there are quite a number of Lusi- tanian plants and animals that are not confined to Ireland, but inhabit also the south of England. A few species ha\-e even invaded the west of Scot- land, although they seem to occur, as a rule, more abundantlv in Ireland than in Great Britain. Among such plants may be mentioned the Irish Spurge (Eiiphorhia hiberna, see Figure 96 1 which grows very abund- antly in the south and west of Ireland, while it is also met with in a few isolated spots in Devonshire. As an instance of a Lusitanian animal belonging to this group, the beetle Rliopiiloiiiesifes tardyi (see Figure 91) may be cited. This weevil is so common in Ireland that it St. Dabeoc'; FlGURF. 9^1. The Irish Spurge tEiipliorbiti liihcnui* FiGlui-: 9.T. Heath UJnl>cocia poUfolui\. Romidstone. is classed among the most injurious Irish timber insects. In Great Britain it is only known as a rare insect in the south-west of England and Scotland. Hence, we now know that the Lusitanian ele- ment in our fauna and flora, though much more conspicuous in Ireland, is not peculiar to that country. This fact greatly weakens the arguments in favour of accidental dispersal. To anyone, moreover, who has made a careful study of the mode of occurrence of these plants and animals in the British Islands, it must be apparent that they are old-established species, most of which are being crowded out or supplanted by newer rivals better fitted to w ith- stand the existing climatic conditions. They all have a discontinuous range, which, as Wallace has taught us, is a sure sign of antiquity. Most of them occur here and there in isolated patches or locali- ties surrounded by species of quite a dift'erent type. KNOWLI-.DGr. MAUni, 1012. I'rnfessor I'orlMs' \u'\\ of the orifjin nf tlic Lnsitai)ian plants wliich lu- tli(iiif,'ht wt-rc coiirnicil to Iiclaiul. was tliat Spain and Ireland wtTc oiui' (linctiy ronnertid with oiu' another hv land, and that tiiis provided ii safe northward passaf,'c for a nnniiier of southern species. The e.xisting Irish members of the Lusitanian element he looked upon as the last survivors of this ancient invasion of the northern territory, contendiii}^ that this event must have taken place in Miocene times lonj; anterior to the Glacial lipoch. when the land in Western Euroiie stood hifjher than it does now. One of the principal difficulties which Professor Forbes' view presents to us is that, if these plants wandered northward in pre-glacial times, they must have survived the Ice Age in these islands. The natural question also occurs to us, could specific identitv have been preserved in so many instances durin;^ such an immense lapse of time fioni the Miocene to the present age ? "I'lure is no doubt, however, tliat ue have still a gooti deal to learn about the Ice .\ge and its supposed climatic conditions. Much remains tjuitc obscure to the i)resent day as to what actually happened during this phase of geological history. .\t any rate it cannot be definitely asserted that the Lusitanian l.iuna and llora could not have survived the Ice Age in In-land. .\s for the persistence of specific identity through several geological periods, there arc some instances known to us where this can be proved to have occurred. It is possible that all the species I have alluded to may have survived from Miocene times to the present day, though we possess no palaeontological evidence for such a supposition. .\11 the same, a better c.\|)lanation of the presence of these animals and plants in the British Islands than the (jne suggested by Professor Forbes, seems to me to be that they wandered northward not by a direct connection between Spain and Ireland, but along the west coast of Europe at a time when the British Islands formed part of the Continent, and that most of them subsequentlv became extinct in the inter- mediate area when the conditions grew less favour- able for their survival. As I have indicated in another [)lace, I quite agree with Professor Forbes that this event must have hajipened before the Ice Age.* Some species may be of Miocene age, others are possibly older or younger. We have no means, in the present state of our knowledge, to determine this factor, but the whole [iroblem forms one of the most interesting chapters connected with the origin of our fauna and flcjra. Patient observation and studs' will in time furnish us with its correct solution. Scliarff, R. F. — "" European Animals: tlicir Geographical History and Geographical Distribution." London, 1907. kb:sE.\kcii i)]:i-H\-cE sociktv. It is the work of the Research Defence Society to put before the public, and keep before the public, the facts about experiments on animals in this country, and the great benefits which have been obtained by the help of such experiments. These benefits are not limited to men, women and children : the animal world also enjoys the advantages gained by experiments on animals. It is better protected against the scourging epidemic diseases, such as anthrax, rinderpest, bovine tuberculosis, and e(|uine lockjaw ; the causes and way of infection of such diseases as Nagana and Te.xas cattle fever have been discovered and proved ; good advance has been made toward a protective treatment against distemper ; and admirable tests have been discovered for the detection of tuberculosis in cattle and glanders in horses. The Research Defence Society was formed in 190S, to remind people what a great national debt of gratitude we owe to experimental physiology and pathology. It began with seven members, and it already has more than five thousand members and associates, and has established Branch Societies in all parts of the Kingdom. It has nothing to do with the actual making of experiments on animals, nor with advising the Home ( )flnce over applications for licenses and certificates under the .Act ; nor does if desire the abolition of restriction of such experiments in (his country. Its work is to publish and distribute literature, to answer all enciuiries, to make all necessary arrangements for debates, and to give addresses and lantern lectures all over the country. The minimum subscription for working expenses is five shillings : but under-graduates and students of medicine arc eligible for membership at an annual subscription of halfa- crown. Larger subscriptions or donations will be gladly received. Associates pay a subscription of one shilling. Of course, the Society wants more members and associates. The work keeps growing, and the more it grows, the better the Society is pleased. There is an endless amount of work to be done. Many of the public know next to nothing about the general character and purpose of experiments on animals at the present time. The common use of the word "vivi- section " hides the fact that ninety-five per cent, of all experiments on animals, at the present time, in this country, arc inoculations, or of the nature of inoculations : that is to say. they involve no sort or kind of cutting operation on any animal. .N'either is it known to everybody that no operation, more than the lancing of a vein just under the skin, is allowed to be done on any animal in this country, unless the animal, through the whole of the operation, is under some anaesthetic strong enough to prevent it from feeling pain. When we consider what measm'eless and permanent gains ha\e been made by mankind, and by the animal world, out of the work of such men as. Pasteur and Lister, we see the good of a Society set apart for the one purpose of keeping the public in mind of the facts of the case. These facts have been in past years obscured, now and again, by prejudice, or by something worse than prejudice. It is the business of the Research Defence Society to popularise the whole subject. As Bacon said of man. that he is the interpreter of nature, so this Society might call itself the interpreter of the interpreters. That would be a line in.ilto for it : " Interpres Intcrprctum Naturae." We hope that many ot the readers of " KNow'l.l-.nc.E" will communicate with the Honorary Secretary. 21. Ladbroke Sejuare, London, W. He will be very glad to hear from them. THE KNOWLEDGE OF THE DEAD NAPOLEON. P.v A. M. r.KOADLI.V. Author of " Xtipoleoit in Caricature." ami so on. A CAREFUL Study of the various foruis of pictorial satire relating to Napoleon in connection with m\ book ''Napoleon in Caricature," led me incidentally to collect and examine the numerous portraits (some of them obviously more or less caricatures), which were made between Julv, 1815, when he went on board the " Bellerophon," and his death at Longwood, nearly six years later. A series of happy accidents Mr. Ihbetson"s term of St. Helena services (accord- ing to the official record) dates from July 28th, 1815, to June 27th, 182.}. On the resignation of Mr. Balcombe he became "' Purveyor to the Household " at Longwood, near w hich house he took up his abode, He was with Napoleon at the time of his death, made a sketch of him as he laj- dead, superintended the sale of his effects, and afterwards drew up --^7- FlGURE 97. The adjustment of accounts from March, 1818, and October, 1820. made three weeks after .Napoleon's death, between .Assistant Commissary Ibbetson and Count Bertrand, now in the possession of one of Ibbetson's descendants. enabled me to identify as the principal of the St. Helena portraitists. Mr. Denzil Ibbetson (1775-1857), an officer of the Commissariat, who joined the department as a clerk in June, 1808, and attained the rank of Deputy Assistant Commissary-General in October, 1810. On Christmas Day, 1814, he was promoted to be Assistant Commissary-General, and in the following \-ear proceeded to St. Helena on board the " Northumberland," upon the deck of which ship he made his first sketches of the Great Man. the general statement of accounts now repro- duced for the benefit of future historians of the last phase. (See Figure 97). The life-story of Denzil Ibbetson. written by me and illustrated by a large number of his unknown and unpublished sketches of Napoleon and his companions in exile now in my collection, will be published in the April number of The Century Magazine of New York. One of the portraits of the Emperor made on board the " Northumberland," given by Ibbetson to Theodore 98 KNOW I.I.DCl Makui. I'JU. Hook, in 1817. aiul ;ittfSttcl by him, was repiuiliicid in facsimile as one of the cliief illustiations in Lithograph pubU.~h Napoleon after death, from the tiiiished oil -pain lilt},' by Assistant Commissary-General Denzil Ibbetson. in possession of Mr. A. M. Hrnadlr\ . M. I'Vedcric Massoir.s recently-published monu- mental work on St. Helena. It also appeaml in my own work, "Napo- leon in Caricature." Much valuable informa- tion concerning M i Ibbetson. who retire from the public service oii June 15th, 1846, with thc grade of Deputy Com- missary - General, and died at Brighton eleven years later, was gi\en me by Lady Ibbetson, the widow of his distinguish- ed grandson, the late Sir Den;{il Charles Jelf Ibbetson. K.C.S.I.. of the Indian Civil Service. Her iuisbamrs aunt. Miss Laura Ibbetson, the youngest daughter of the Purveyor at Longwood, still lives, and amongst other valuable relics of Napoleon owns one of the oil-paintings of the dead Emperor, which Mr. Ibbetson subsequently made from his original sketch of May 6th, 1821. .My present concern is solelv with the posthumous masks and [portraits of Napoleon, and there can be no doubt but that Ibbetson enjoyed special facilities for securing a good likeness. That he was capable of executing a good drawing his ■' Northumberland " portrait sufficientlv shows. The Ibbetson oil-i)ainting of the dead Napoleon measured about thirty inches by twenty-five inches. The one in my own collection now reproduced (sec FigureOH) bears a lengthy inscription in Ibbetson's handwriting. Duplicates of this picture by Ibbetson are at Hampton Cotirt. and, as before stated, in possession of Miss Ibbetson, and I have quite lately discovered that there exists a fourth, whicli for more than twenty \ears has belonged to a giutlcman Commissary-General Ibbetson s paintings, in which the artist is erroneously described as "Captain Ibbetson, K.E." residing in Ldinlnirgh, and is surrounded with an el.nborale frame bearing the letter N in each corner. .\t the back of this particular re|)lica of Ibbetson's |)f)rtrait is a note by the artist similar to that on Miss Ibbetson's co|)y and on mv own as follows: — " Painted by I). Ibbetson from a ski-tch made by him (at St. Helena), of Napoleon, the morning after his death, which took [)lace in the evening of 5th May, 1821, at sunset. The features had fallen away during his illness, but the fullness in the throat remained. The countenance was verv jilacid — the colour of the skin very yellow, and there was a redness about the eyes which had the appearance as if the head had been beat and bruised. A picture similar to this was painted by the same person at St. Helena immediately after the sketch was taken, and was given hv Sir Hudson Lowe, on his return to England after the death of Napoleon, to King George IV. This ()icture is now at Hampton Court, and it appears liy a periodical work called T/w Art Union, that till- performance of it is erroneously attributed to Madame Bertrand." The owner informs me that his picture measures two ttet four inches b\- nine- ty en ami one-eighth iiu:lu-s. It is in fairlv good condition. The Hampton Court copv is said to have been given by Sir Hudson Lowe to King George I\'. In 1S5 5 a lithograph ' improved " from one or 'ther of the four Ibbetson paintings, and now repro- duced (see Figure 99), was published, but the artist, although still li\inir. was erroneousK- of UlpiU\ .iKi: 1(11). Napoleon after death, published by S. and J. I"uller, M, Kathboue Place, London, July Ibth. l.S^l.and described as being lithi>.t;raphed from a sketch made by Captain Marryit fourteen hours after death at the rc(|nest of Sir Hudson Lowe, and with the permission of Count Moulholon andtiener.d Herlrand. March. Ml. KXO\\Li:i)GI-:. gf) Napolcoa alter death, from a walci-culoui on straw paper bv a Chinese artist at St. Helena in 1821. In the collection of Mr. A. M. Broadlcy. described in it as Captaii\ Ibbetson, R.E. Captain Frederick Marryat. R.X. (1792- 1848) the well-known novelist, was, in June. 1820. appointed to the ■■ Beaver " sloop \\ hich was emplo\ed on the St. Helena station till after the death of Napoleon. Marrvat w as also permit- ted to make a sketch of the illustrious e.xile as he lay dead on the historic Austerlitz camp -bed- stead. Of this drawing he made and signed several replicas in pen and ink and wash ; one of these is now my property. Marryat's posthumous portrait of Napoleon was almost immediateK' published in England, German\- and France. On the English version we read : — " Sketch of Bonoparte, as laid out on his Auster- litz Camp Bed, taken by Captain Marryat, R.N., fourteen hours after his decease, at the request of Sir Hudson Lowe, Governor of St. Helena and with the permission of Count Montholon and General Bertrand." The drawing must have been sent to. London almost as soon as the despatches announcing Napoleon's demise, for it was brought out by Messrs. Fuller, of Kathbone Place, on July 16th following. (See Figure 100.) In his admirable book. "" A Polish Exile w ith Napoleon," Mr. G. L. de St. M. Watson sa\s : " It was on May 6th, at 8 a.m., that Marryat sketched, with an austere frugality of line, his noted profile of Napoleon on the camp bed, which he gave to Captain Crokat. of the 20th Regiment, and which was published on July 16th by S. and J. Fuller, as a lithograph and also as an etching, and on July 18th by J. Watson, as a soft-giround etching." Marrvat (juitted St. Helena in the " Rosario " on May 16th. There were two or three French editions of the Marryat plate. In that of 1840 the descriptive text reads : '' Napoleon Grave par W. Humphre\' d" apres le dessin fait a St. Helene par le Capitaine Marryat, C.B., officier de la Legion d" Honneur, iiiic liciirc aprcs la mort de 1' limpreur." In view of the wide-sjiread distribution of these Marryat death- bed portraits it is almost incredible to relate that the presence of one of the sketches in a local museum was quite recently proclaimed to be an event of almost world-wide importance. The picture was at once reproduced as a great historical and artistic discovery in a large niunber of London and provincial newspajiers, to the astonishment and dismay of Mr. Clement Shorter and other stu- dents of St. Helena iconography. In the interests of true history, I addressed the follow ing letter to The Times, in which the " latest Napo- leonic find" had been dulv annoimced : — "There are several authentic por- traits of Napoleon after death in existence practi- callv identical with that reported to have been recently discovered at Maidstone. One of these (signed by the artist) is in m\ collection. I have seen two others, and a fourth was latelv in possession of a granddaughter of the artist. Lithographs after Marr\at's sketch were subsequently published both in London and Paris. A similar draw ing was made h\ I)e[Hity FiGUItE 102. Pistrucci's lithograph of Napoleon after deatli. London. 1S22-J. U-Ki; 1(13. De;itliiiiaskof Napcjlini in the collection of Mr. .-V. after Dr. .Antoiniiiarchi, M. Broadlev. K\o\\Li;i)r,i:. March, 1912. C'oininisriary l)on/il Iblietson (tlu- j;i:murton the back or craniological part." .\ second cast was i)resumablv taken bv Dr. .Arnott, and a copy of this, officially stated to have been presented by .Arnott to John (iawlcr Bridge, Court Jeweller to George I\'., was recently sold at the dispersal of the Bridge relics in Dorsetshire. It was stated at tile time that " only two casts were taken at -St. Helena, and the matrix destroyed. The other cast belongs to the French Government, and is in the Invalides at Paris." The first fact should be ofRciall\' verified, as the second is erroneous. The cast in the Invalides is from the so-called Antommarchi I IGL'Kli 106. CJrij;inal water-colour sketch of Napoleon's Funeral (Nhiy, 1.S21), in Mr. A. M. Broadley's collection. years later, [irior to the removal of his remains to I-" ranee, his features appeared to have undergone verv little change, and they still attested the correctness of Ibbetson's death-bed sketch. (See Figure 104.) Tile last word about St. Helena has not been said, but much new light is thrown on the " Last Piiase" In- the work' of Mr. G. L. de St. M. Watson, who. before writing his scholarh- and instructive book ".A Polish Kxile with Nai>oleon," with exem[)lary patience went througii tlie whole of the Lowe MSS. in tiie British Museum, as well as a mass of other new and valuable material. THE GRAIMIIC EXPRESSION OF SENSE. PART II. KIN rixr, PRO i; I, i: MS i;v .\NN.\ DK.VNK liLTCHllK. l.N a ()iiper read before an .\mericaii Typographical .\ssociation. Mr. T. L. de X'iiine, who is regarded as the most eminent of Hving printers, remarked that we make use of two distinct styles of printing, ■'Mascuhne," or that which is noticeable for strength and absence of ornament, and "Feminine." that w hicli is characterised by delicacy, and b\- the weak- ness which always accompanies delicacy ■■ The object of the masculine st\le "' he sa\ s. " is the instruction of the reader, and to this end the printer tries to show the intent of the writer by the simi)lest methods For this he relies most u[)on the plainness of hist\pe, the blackness of his ink and the excellence of his paper." In a scientific age this somewhat enigmatical description of two graphic methods of expressing meaning, leaves much to be desired, and may be interpreted thus : — For "simple" read, "inatiequate," for "strength" read "coarseness" and for "plainness of type" read " monotony of st\le, consec]ucnt upon the degenera- tion of the grajjhic symbols." The antithesis of " delicacy " is not " strength " but " vulgarity." i.e.. the ignoring of delicate distinctions, inaccuracy of definition, and loose generalisations. The triumphs of modern Engineering, of C'hemistrv, of Astronom\-, and indeed ail the developments of modern civilization are due to the science of Graphics, to the accurate notations of the mathematical and exact sciences, and to " delicacx " in all the graphic arts except that of the printer. The delicacv of the balance is not weakness, strength is due to a nice adaptation of means to ends, it is measured by its capacity for work, and the progress of some sciences may be attributed to the observation of extremely fine differences in the form of minute organisms. Astronomy is not the same science as it was before the invention of the telescope. Why should typography be the same as it was before the invention of the magnifying glass ? Print which had its genesis in the imitation of the forms of animate nature, should be developed along the same lines. The printed page should bear a comparison with animate nature, simple indeed to the superficial observer, and easily read, but upon inspection, revealing hidden meanings and affording more and more information to the student. The leaf does not obtrude its structure and the arrangement of its veins and cells upon the passer- by, but repays investigatiofi if the student w ill but stay and learn in Nature's school from the only teacher who is infallible. C'omi)are the delicate ramifications of the skeleton of the leaf under the magnifying glass with the coarse lines and empt\' spaces of the best specimen of the t\pefounder"s art, and the contrast will strike the beholder with astonishment and lead him to reflect upon the wav in which the lessons of Nature have been thrown away upon the masculine printer, who has lost the instinct of imitation as well as his \isual imagination. The object of an educational print is not that he who runs ma\' read, but that by close investigation the letters and words may be photographed upon the brain, and be automatically reproduced by the hand after constant repetition. The more information, then, that the idiograph gives about itself the better, and for its study a very excellent magnifying glass can be bought for the moderate sum of fourpence halfpenny. To Mr. F. A. Bellamy's reasonable com()laint that he has had to use twenty-five words to exiilain what the printer could have exjiressed b\- one letter, it is futile to answer : " That is true, but see how good is the paper and how excellent the ink ! " The final s is always pronounced as z in English and in French, when pronounced at all, and the additional vocal effort necessary to produce the hissing sound is logicalh- expressed by an additional letter, "aS"— "aSS," " IS " — " MSS," differen- tiating to the eye the unimportant auxiliary words which are pronounced without any effort, from the important idiographs. which are stressed. This being the Englishman's normal vocal habit, the printer should indicate where he has omitted a letter bv the sign of contraction v as tl§, thl^ — OU^, and so on, where the addition of a line from left tt) right downwards is understood to mark the contraction which so often occurs in his w ork ; thus the letter j is logically printed = dlg'J and illogically printed with a dot j, idlg = i^ It is not the desire of the printer " to instruct the reader," or the "simplicity of the means adopted by him," which causes constant confusion of meaning, and perpetuates the curse of Babel ; it is rather the fact that while the Fundamental System of the Stars is " brought up to date," the printer remains four centuries behind, at the point in the history of writing when the typemakers and punchcutters usurped the functions of the scribes, arresting its natural develoiMiient, and causing w hat should be a living and growing art to be crystallised, or rather fossilised, in the present notation. Professor Leduc, who has chosen the accompanying extract for a specimen of the Orthotype notation. KN()\VLi:i)GH MAHf II, 1912. Cdinplaiiis lliat m> ICii^'lisliiiian pmnoimrcs liis name corrc'ctK'. aiul that ho is unaltlu to converse witli liis l-Inj^lisli roiifriTcs ahout liis theory of Osmotic Growths: if lie speaks luiglish tliev cannot nncler- stand him, and if tliey speak I'ronch the result is the same. The specimen of European idiograpliy uhicli illustrates this article is perfectly understandable In' sight to any educated Englishman, and that w ithout any mental translation into his own language, hut if it is transposed from the ordinary jirint into linglish speech sounds it is wholly incomprehcnsilile. By the helj) of a straight line in four positions. I — V ,/. four segments of the circle, and the dot. C w» '^ 3 •, which geometrical elements arc found in all letters and symbols and can be easily added to the print, the reader is enabled in half-an-hour, w itli the assistance of a Frenchman, to associate a certain fGCliPg of vocal positions and movements w ith his \isuai impressions, and he has nothing more to learn about brench pronunciation. By the same amount of repetition and practice which he willingly employs in order to be able to sing a simple tune or to plav it upon the pianoforte, he will be able to transjjose this extract into speech sounds, so that any French- man can understand Professor Leduc's meaning, without that mental distraction which is caused bv constant reference to the context to discover what French words have been uttered. The automatic assumption, by the vocal organs, of the positions indicated by the letters and signs, is caused by a function of the brain similar to that which guides the fingers and hands to the rigiit keys of the instrument automatically, not b\' tlie conscious will of the performer, but b\- a subcon- scious telegraphic ajsparatus, which communicates from eye to tongue, and is called association of Sign and Sound. After this one extract has been in this manner translated into speech sounds, any French book can be read out loud without dillicult\' or h(;sitation, provided, of course, that it is proi)erK' printed, or corrected by the hand of the student or teacher. C"onversation being merely the rc|)roduction of former impressions upon the brain, will by this system be regulated by the amount of literature which which has been perceived by the eye and ear, and automatically rci)roduced by the hand and tongue. .^11 that is worth saving is to be found in the literature of the classical languages, and there is no advantage to be gained by learning to talk twaddle in more than one language, after the manner of conversation books, primers, and grammars. The results of many experiments have proved the truth of the above statements. Even without under- standing what they are reading, foreigners have been able to convev the meaning of a book by speech sounds to the complete satisfaction of a native without the help of phonetic spelling or transcrip- tion; the writer, for example, has read S|)anish in this way. The short extract from pages 102 and 10.5 of Professor Leduc's work, " The Mechanism of Life," contains out of two hundred and sixty-four French words, one hundred and eighty-four English, i.e., international words which are easily recognised 1)\- sight. Subtracting prejjositions. pronouns, conjunctions and often repeated auxiliary words, such as form twenty-five per cent, of all European writing, we arrive by a rough computation at seventy-five per cent, or three-quarters as the proportion of French and English words which are international in scientific literature, and it is this European Idiograph\% as a means of universal communication and a basis of modern civilisation, which should command the attention of scientific men and at all costs be preserved from the destroying agency of the " phonetic iconoclast." The geometrical kt'v xsliicii indicates tlie position of the \-ocal organs in producing the \'owel sounds introduces no new element into print and can be learnt in five minutes. While preserving the sequence of letters and number of component parts of the idiograjihs. upt)n the invariability of which legiliility depends, tiu- Orthotxpe Notation shows tiie pronunciation of European languages at a glance. The juxtaposition of two letters or signs indicate invariable sounds caused by two positions of the vocal organs and their niovtinents from one position to the other. In this way the printer's one hundred and four self-inconsistent ways of writing down thirteen ]'2nglisli nowcI sounds are brought into a logical and practical system. The superscript dot The superscript sign The sign "aw"' The sign The sign The sign The sign The sign is the dot of tlu' letter ... ... ... 1 is the ba<'k of tile letter 6 is the right hand convexity of the letter O is the perpendicular diameter of ... 6 is Seen in the serifs of ... ... ... W is the letter U is the letter A is the German ... ... ... ... U, March. 1912. KNOWLKDGE. 103 Lq paleontologie naus.apprerd que les premiErs. Etres ^ont^apporus dans les.eaux, les. Etres les plus. anciEPS des temps primaires qui, dars revolution des. Etres vivQPts, reprcseptent une pcriode plus lopgue a Elle §eule cue tautes les.autres reunies, etaient taus.Qqnatiques. D autre A n ' ' ' part, taus les. Etres yivQPts ^ont cop^titues ^urtout par.des liquides par. des ^olutiors de cri^taloides et de colloides, ^epQres par.des mEm- branes , osmotiques a travErs IcsquElles ^'affEctuent de pErpetuEls, echarges. EpfiP les niErs QctuElles les vastes laboratoires de la vie sopt, egalemcpt les ^olutiops de cri^taloides et de colloides. C'Est dopc. daPs Tetude des liquides dQPs I'etude des ^olutiops, que Fop doit decouvrir. la nature et I'origine de la vie. La vie Est . un . ep^emble de fopctiops, de trap^formatiops _ enErgctiques qui ^e preseptent a nous comme les resultaptes de la forme, ce la structure de la compositiop des. Etres vivapts, c'Est. a dire des formes. Exterieures, iPterieures, et moleculaires des. Etres vivapts. Tous les. Etres vivapts §opt formes de cavites closes, remplies de liquides, ^olutiops de cri^taloides et de colloides, limites par. des membranes osmotiques. Le premier pas daPs I'etude de la vie et de ^on . origine doit doPC.Etre I'etude des forces et des circop^tapces physiques capables d'organiser aiP^i les liquides, de donner des cavites closes eptonrees de mEmbranes osmotiques d'ass6cier de grouper ces cavites, de les differepcier, de ^pecialiser leurs fonctiops daps I'evolutiop de I'ep^emble. Ces forces et ces circop^tapces physiques ce ^opt preci^emept cElles qui donnent les croissapces osmotiques, et nous avops vu que cElles-ci avaient nop ^eulemept la structure, la forme Exterieure d'up grapd nombre d' Etres vivapts, mais.cpcore les pripci- pales fopctiops de la vie. De toutes les . opimops qui opt.cte formulees ^ur. les.origines de la vie et des, Etres vivapts, cElle qui attribue les 104 KN'OW'I.I.DCE. MAKfii, 1 ert, dQPs, p = n. CORRESPONDENCE. ABDLT I'HI-: I'RISKCTION OF AN ANGLE. To the Editors of " Knowledge." Sirs. — The division of an angle into three equal parts forms, together with the quadrature of the circle and the duplication of the cube, the three most renowned problems of Greek mathematics. As its algebraic expression leads to an irreducible equation of third degree, its construction cannot be made by using only the line and the circle. Knowing that, one mu.-:t be sure that the solution given by Mr. C. S. Bingley in the November number of "Knowledge" (page 435) cannot be right. Mr. C. S. Bingley asserts, without any demonstration, that — using his signs — the distances BJ=J K = KC, and from this concludes that the arc B C is divided by J and K into three equal parts. Now. it is easy to see that this is not true. By taking A D and its perpendicular in A as axes of rectilinear coordinates, and supposing A B = .\ C = l and the angle B A C = 2o, the coordinates of E will be (i.O), and so will be B (cos o, sin o), F (:t+cos a, ^ sin o), H= (ji + sino\ 4 ,'■ J being on the line A H and on the circle B C will have the coordinates / 5 + 2 cos a 2 sin ), instead of I cos , sin -^ 1 1^29+10 cos a \/ 29+ 10 cos which would be when the construction is exact. By designing the angle J A D with «, the following table shows the error of the construction for a = 10°, 20°, 30°, 40°. The angle S has been 5 + 2 cos a coinpu ted by cotg 5 = 2sina -'=°*«" ' 2 sin o ■ a 10° 20° 30° 40° a 3 0 3° 20' 6° 40' 10° 13° 20' 2° 51' 10" 5° 40' 40" 8° 27' 2" 1 1° 9' 4" The difference S — — is, as we see, not inconsiderable, and not onlv due to errors '' in the drawing." FlclKh 10/ BUD.\PEST. ERNEST KN()\\Li:i)r,i:. Makcii. 1912. THK SPKCTROSCOPK ASII i I ol Mil IMPACT THi:m)t h.-id thc»pp(irtiinity of cxainiiiiiiK .-md com- pariiiH in ilrlail llic several spoclroscopic observations of Novae as n-Kards the correspondence between them and the deductions of the theory, but it appiars to nie that the main phetiomena arc siifRcicntly striking, and that the general agreement, providing as it does the fundamental working hypothesis, endows the details with an increasing interest. Novae have presented to astrophysicists some of the most bewildering problems in the whole of astronomy. Their sudden appear- ance, followed by declining luminosity and the extraordinary characteristics of their spectra, defied explanation. Yet iii their spectra (considered in conjunction with telescopic observations), was written the secret of their origin. It behoves us to remember that Professor BicUerton's beautiful generalisation was conceived and worked out at a time when observational confirmation was meagre, and this should increase our respect for it in the light of subsequent discovery. I doubt if Professor Bickerton himself ever imagined to what extent his early conception would be enriched and strengthened by continued observation and discovery. The spectra of Novae are of supreme interest ; they tell of matter in the crisis of extreme stress, matter under conditions which we cannot reproduce in the laboratory; and every small detail in them is worthy of close study. All these details may not yet be capable of explanation, but the main phenomena arc met by the theory of the third body, and it is surely most logical to adopt as a working basis the one theory w^hich explains the most characteristic features of such spectra. Without attempting to discuss the various other aspects of the theory from the standpoint of general astronomy, we ma.\- consider briefly these spectroscopic phenomena on their own merits. The first circumstance which strikes the attention is the emergence from the general blaze of the Balmer series of hydrogen lines, but not as we are accustomed to see them either in the laboratory or in normal stellar spectra. They are wide bands with diffused edges. This appearance has been sufficiently emphasised in Professor Bickerton's own writings, and his explanation of it as a necessary deduction from his theory appears to me to be the only one possible. In an examination of the spectrograms, we notice that the width of the bands increases as we proceed along the series towards the violet. This is a necessary consequence of prismatic dispersion, as will be evident by plotting the dispersion curve of any spectrogram giving the normal hydrogen series in a stellar comparison spectrum, e.g., the Stonyhurst spectrogram of Nova Persei with that of o (ieminorum as a reference spectrum. Therefore, to measure the amount of widening, it is necessary first to ascertain accurately the form of the dispersion curve repre- senting the varying degree of dispersion under which the several lines are presented. Although great pressure will widen lines, rendering diffuse lines which are normally sharp, it is clearly quite incapable of explaining the widened lines of Novae for the reasons given so clearly by Professor Bickerton in" Kxowi.iiDGl^ '" (September pp. 365. .}66). namely, that the bands remain sensibly constant and bordered on the more refrangible edges by dark absorption lines. In passing it may be interesting to note that in accordance with the Doppler principle, spectrum lines should be widened by reason of molecular motions in a source in a state of high thermal disturbance, but this effect is very small even at high temperatures. It is, I think, very desirable that all available spectroscopic observations of Novae should be collected and discussed on the basis of the theory of the third body, especially as regards the careful comp.irison and reduction of all spectrograms. According to the theory, the extreme edges of the widened lines represent the maximum velocities in the line of sight towards and away from the earth of the gaseous shells of the elements to which such lines are spectroscopically attributable. It is important to ascertain whether these velocities are what the respective atomic weights would lead one to expect ; also whetlKT lines of any one element all indicate by their measured displacements the same velocity. These and several other points re<|uire investigation, but there are many factors which have constantly to be kept in mind. One of these is the very important ijiieslion of possible elemental dissociation. If this has been claimed for elements present in normal stars, subject to normal temperature conditions consequent on their locality, how much more must the possibility be considered in the case of the violent forces brought into play in stellar impacts. And if this dissociation occurs, then the velocity in the line of sight calculated from the displacement of one line of an element would not necessarily be the same as that deduced from another line normally attributable to the same element. If the third body as a whole be practically stationary in space, then the centres of the widened lines would coincide with the corres- ponding lines of the comparison spectrum ; but if it should happen that there was considerable motion in the line of sight, a complicating factor would be introduced, for in addition to being widened, the lines would be bodily shifted. It will be seen that the detailed interpretation of such spectra is by no means an easy matter. The measurement of the spectrograms is in itself beset with difficulties on account of the diffused edges of the bands merging into a background of more or less continuous spectrum. Combined with this there is the question of blends, differing intensities of the lines, and the varying sensitivity of the photographic plate to light of different wave-lengths. With reference to the displacement of lines due to the motion of the source in the line of sight, it should be pointed out that the magnitude of the effect varies with the wave- length of the line in question, the displacement corresponding to any given velocity being greater in the red than in the violet. If, then, we are considering a practically uniform dis- persion like that given by a grating, the linear shift will be more apparent in the region of longer wave-lengths. The general formula for calculating the velocity in the line of sight from the observed displacement mav be given as : — v = v'A^^' where V --= velocity of light \\ = normal wave-length of the line in question Xo = the wave-length of the displaced line. Since Xi — X2 represents the change of wave-length or dis- placement, the formula becomes: — v=vd_ X The displacement which would be produced in any given line bv a given velocity in the line of sight is thus : — The linear shift corresponding to a given velocity is thus twice as great at X 6000A° as at X 3000A° when represented on a wave-length scale of equ.al parts, which is approximately the condition with grating spectrograms. In the case of prismatic spectra, we have the two effects of shift and dis- persion acting in opposition, but the increasing dispersion in the region of shorter wave-lengths very umch more than compensates for the decreasing line shift, hence the displace- ments appear more obvious with decreasing wave-length. These are some of the circumstances which render the study of the spectra of novae a matter of considerable complexity, but of the general truth of the interpretation supplied by the theory of the third body I personally feel no doubt. It is probable that difficulties, apparent or real, may be encountered in matters of detail, but the theory which Professor Bickerton has formulated supplies a fertile, and I believe, a true basis for the future investigation of these remarkable celestial objects. Small discrepancies, or apparent inconsistencies when carefully investigated may throw un- expected light on the processes involved, for there nmst follow many problems involving conceptions of great interest to students of atomic physics, such, for example, as the stabilit\' of the elements referred to above. Kast Crovpon. CHAKLI.S W. RAFFETY. NOTES. ASTRONOMY. By A. C. D. Ckommki.in, B..\.. D.Sc, F.K..-\.S. THE A.XIS OF MARS.— In "Knowledge" for last October, I described Dr. H. Struve's method of finding the position of the axis of Mars, and its compression, from the motions of the poles of the orbits of Phobos and Deimos. He has now published a revised result, including the observations of 1907 and 1909 (when there were many visual observations at the Lick Observatory, and photographic ones at Pulkowa). He obtains results very near his former ones, but oiititlod to considerably more confidence. — North Pole of Mars at epoch 1880-0— K. A. 317" 4'-4 ; Annual Increase 0'-463. N. Dec. 52" 35'-6; .Annual Increase 0'-239. Obliquity of Mars Equator to orbit, 25' lO'. Polar compression iJir. Centre of circle of Poleof Phobos orbit 317° 3'-7. N. 52°36'-0. Distance from Pole of Mars 0° 0'-6. Radius of Circle 57' -5. Annual angular motion of Pole 158 . Eccentricity of orbit -017. Centre of circle of Pole of Deimos Orbit 316° I' -2.. N. 53' 16' -0. Distance from Pole of Mars 0' 55' -5. Radius of circle l°44'-0. .-Annual angular motion of Pole (>°- 374. Eccentricity of orbit -003. I understand that these values will in future be used for the Ephemeris for Physical Observations of Mars. THK I'KILKI-: AND MASS OF U RAX L"S.— Mars is not the only planet for which the satellites give interesting information as regards its figure and the position of its axis. They are particularly valuable in the case of the two outer planets of our system, on whose surfaces it is difficult to detect any marliing. Mr. Marth long ago recognised that the plane of the orbit of Neptune's sateUite Triton was shifting, which is evidently due to the equatorial protuberance of Neptune. The motion is so slow (one revolution taking about five hundred ^nd eighty years) that a longer time must elapse before the position of Neptune's axis is accurately known. A first approximation was given by the present Astronomer Royal and Mr. Edney, in Mon. Not. R.A.S. April, 1905. A more elaborate discussion by .Mr. David Gibb [Proc. Royal Soc. Edinb. 1908-9) indicated that Neptune's North I'ole is in R..'\. 295-6, N. Dec. 42°- 8. Its equator in that case is inclined 21° -2 to the orbit of Triton, and 27' to its own orbit. In view of the probable retrograde rotation of Neptune it might be more proper to call the above Pole its South Pole. In the case of Uranus its nearest sateUitc Ariel, is only half as distant from its primary as Triton from Neptune. There would consecjuently be a nnich more rapid shift of the orbit plane if it differed from the equatorial plane of Uranus. As no such shift has been detected, it is certain that the two planes piactically coincide. This is further shown by the fact that the planes of all the satellites are sensibly the same, l-'or if they were inclined to the equator they would shift at different rates, and their agreement at the present time would be most improbable. Hence we may take the position of the axis of Uranus as known. The R.A. of its North Pole for 1900 would be 75°- 81 ; annual increase "- 014: North Dec. 14°-79; annual diminution -"OOl. Orion is therefore the North Polar constellation for Uranus. We cannot, as in the case of Mars, obtain the oblateness of Uranus from the shift of the orbit planes of the satellites, for no shift appears to exist. Dr. Oesten Bergstrand, Director of the Upsala Observatory, has endeavoured to determine it from the motion of the peri-uranium of the inner satellite Ariel. He has utilised the observations made at Lick Observatory since 1894, The orbit is so nearly circular that we cannot place great confidence in the result. He finds eccentricity of .Ariel's orbit -007, annual movement "f peri-nranium 15°; the cor- responding results for Umbriel ari^ -008, 4° or 5". The value of the compression depends on the distribution of dcusitv in the globe of Uranus. Rotntion Pcrioil. Hours. If Uranus is homogeneous the compression is ib ... — If it is arranged like Jupiter, the compression is ■}« •■• 17-6 If it is arranged like Saturn, the compression is i\i ... 11-3 Value adopted as most probable rro ... 13 It would seetn, then, that Uranus takes distinctly longer to rotate than Jupiter and Saturn do, and the same appears to be the case with Neptune from the figures given above. It is perhaps not surprising, from the fact that they are intermediate in size between the giant planets and the terrestrial ones. ROTATION OF VENUS.— M. Belopolsky has recently published another spectroscopic determination of the period of rotation of Venus, which he again finds to be not very different from one day. It will be remembered that Professor Lowell's spectroscopic determination favoured the long period. Mr. Scriven Bolton has contributed a series of drawings to The Journal of the British Astronomical Association, which lead him to a period of 2i^' 28"". Mr. McEwen adds a note reconnnending that too Tuuch weight be not given to this determination, owing to the extreme delicacy of the markings on ^■enus. I'.OTANV. By Professor F. Cavers, D.Sc, F.L.S. CVCAD STEM-STRUCTURE.— The Cycadaceae, as the lowest group of Gymnosperms, and therefore of F'lowering Plants, now living, are of such importance in the evolution of plants that every new detail discovered regarding their structure is of interest. In a recent paper. Chamberlain iBot. Gaz.. 1911) has described the structure of adult stems of species of Zainia. Ccratozamia. and Dioon, and has considerably supplemented the information given by earlier writers. In Dioon spitiiilosiim the wood zone in a plant six metres in height reaches a width of ten centimetres, far exceeding the extent of the wood zones previously described for any Cycad. This species shows a remarkable resemblance in detailed stem-structure to the Cretaceous fossil Cycad, Cycadeoidea, one of the members of the extinct family Benuettitales which were in some respects more primitive than the Cycads, and formed a link between this group and the remarkable Cycadofilicales or fern-like seed-plants. No groulh rings (" annual rings ") were found in the wood of /Cauua ftoridana or Ccratozamia mcxicana ; Dioon spinulosum and /). cdide have growth rings, which in the former species answer to the periods of activity which result in the formation of crowns or cones, but which in D. cdnle do not correspond to such periods. The protoxylem, or first- formed wood, consists of scalariform tracheids, from which there is a gradual transition to the tracheids with bordered pits, the latter forming the chief part of the wood. Scalari- form tracheids are also found in the large medullary rays. INK-CAP TOADSTOOLS. — The small toadstools belong- ing to the genus Coprinus are remarkable in that the cap with its gills after a few days becomes converted into a black semi-fluid mass. The biology of these curious toadstools has been studied already by Buller in his brilliant " Researches on Fungi," but Weir {Flora, N.F. Band 3. 1911) has made a very extensive investigation of the genus Coprinus and dis- closed many new and interesting facts in the physiology of these plants, and his long paper may be summarised as follows. In addition to the differentiation of the tissue mto central conducting filaments and strengthening outer tissue, ins K NOW 1. 1: DC I- MMini. I'd 2. tin- sCalk ami cap contain a systi-tn of iiiilktiilx-s, aritl a Cdimccd'd svstom of air-cavities is alsn tlevclopcil ~[hr wliolf offering an analogy widi the arranjjfiiicnl nf the tissues in mie of the liiKher plants. The deli(|uescenco of the cap is a kind of self-dijjestion, occin-rinK <|uitc iiulepcndcntly of the action of bacteria and etVecled by a number of ferments which act upon proteins. The liorn-likc substance ehilin occurs not only in the coats of the spores, but also in the outer tissue of the stalk and cap: the yills contain practically no chitin, and it is probably owinj^ to this that the ^'ills deli(|uesce more readily than the other parts of the fruit-body. Any part of stalk or cap is capable of regeneration, new fruit-bodies being formed by this process ; the plant shows definite polarity, there being greater power of regeneration in the side facing the substratum or turned from the light. Numerous grafting experiments were made, the yoimg fruit-body of one species being grafted on the stalk of a different species: fusion took place between the threads of scion and stock, and the form of the mature fruit-body showed evidence of reciprocal action between the two species: the spores, however, were not influenced by grafting. Simil.ir grafting experiments were made with various fungi in addition to Coprinits. and in some cases Weir found evidence of reciprocal parasitism between the two species used. Like Buller's work, this paper by Weir is perhaps even more notable as an indication of the interesting lines of research it suggests than for the actual results obtained by the writer, novel and striking as these results are in themselves. PHOTOSYNTHESIS IN ALGAE.— It has long been known that the green pigment chlorophyll absorbs chiefly the red and blue rays of light. In plants possessing other pigments in addition to chlorophyll, the absorption spectrum is some- what diflerent. Dangeard {Comptes rendus, 19111 has now proved that even in green plants the infra-red rays are absorbed and utilised in growth, though there is apparently no absorption of the ultra-violet rays. Dangeard has also found that the blue-green algae (Cyanophyceae) are capable of utilising the infra- red rays to a large extent. Meinhold iBcitr. Biol, tier Pfltnizen, 1911) has studied the Diatomaceae from this point of view, and finds that here, as in green plants, there are two maxima of assimilation, one being in the red and the other in the green-blue between lines C and F — not, as in green plants, in the blue between lines F and G. The results of experiments on assimilation, on being compared with those obtained by means of the spectroscope, show that the maxima of absorption and assimilation by no means correspond ; that is to say. some of the rays which the plant absorbs are not utihsed in photosynthesis, though they may be of importance in other processes of life. BIOLOGY OF THE HORSETAIL iEOUlSHTCM).— In an interesting paper, Ludwigs {Flora. N.l". Band 3, 191 1 1 gi\es the results of various observations and experiments he has made on the Horsetails (species of Eqiiisetiiiii). He finds that there is a characteristic difference between the leaves on the underground and aeiial stems. The leaves of the rhizome, which persist much longer than those of the aerial stem, bear hairs on both sides; tho»e on the upper side of the leaf serve to protect the delicate tissues of the growing-point, while the hairs on the underside secrete mucilage, making the growing tip of the rhizome slimy, and therefore helping it to push through the soil. On the aerial stem these hairs occur on the upper surface of the leaves, but not on the lower. Ludwigs finds that by suitable culture methods, the rhizome can be made to grow into an aerial shoot, and vice versa : annual shoots may be made perennial; the normally colourless and unbranchcd fertile shoots of the field horsetail may be caused to develop chlorophyll and to produce branches ; male prothalii can be changed into female, and vice versa. Regeneration takes place when pieces of the shoot, or even of the prothallus, are cultivated : in the latter case, new prothalii grow out and may become det.ached. The author states, in opposition to Mower, that the nutrition of the developing spores is not due to the degeneration of some of the spore-mother-cells, but solely to the special nutritive layer or t.ipclum. He also ilescribes the manner in which the antheridiiim opens to discharge the male cells; apparently the process resembles that seen in some mosses, there being a special cap or lid-cell which is del.iched, after becoming mucilaginous and swollen. THE "CALYX-TUBE '• OF ROSACEAE.— The family Rosaceae shows great variety in the form of the flower, largely due to the varying degree of " perigyny " or '" hemi- epigyny ■' exhibited by the flowers in the different genera. Hillmann iBeih. Bot. Ceiitralblatl. Band 36. Abt, ll has made a careful examination of the so-called " calyx-tube " or "receptacle-tube," for which he prefers the term "hypanth," and from his investigations on the anatomy of this tubular structure he concludes that in this family we have to deal with different kinds of tubular organs, which are not all formed in the same way. In the Rose, the tube is purely an axial structure, a hollow prolongation of the receptacle or top of the flower- stalk. In the Apple sub-family (Pomoideae). the "receptacle- tube " consists of both axis and calyx. In most of the remain- ing members of the family, however, the hypanth is the product of fused leaves. Hillmann believes that this is clearly shown by the structure of the flower in Avens, where the flower axis is prolonged above the cup-like outgrowth, and the latter can hardly be explained otherwise than as the product of congenital fusion of leaves. EVOLUTION OF ALGAE. — In recent speculations on the evolution of plants, it has generally been assumed that the earliest vegetable organisms possessed chlorophyll and belonged to the green algae iChlorophyceael. That these arose from green flagellates, while the brown and red algae arose probably from brown and red flagellates, appears to be supported by the discovery of transitional forms in each of the three series, green, brown, and red. Most writers on the subject, however, have assumed that whatever the course of evolution may have been, the green algae came first. This assumption has recently been combated by Brunnthaler tBiol. Ceiifralblaff, 19111. who argues that in order to arrive ^t correct views regarding the phylogeny of the algae, it is necessary to take into account the probable conditions of life in the earlier periods of geological history. He rejects the view that there is any direct relationship between algae and flagellates, and regards the living forms of the latter as the termination of an ancient series of organisms, of which the earliest members may, however, have given rise to the red algae. According to Brunnthaler, the most ancient algae are the red forms, or Rhodophyceae, and he bases this view upon the following arguments. The earliest plants must have been marine free- swimming forms: the absence of free-swimming forms among the present-day red algae indicates the great age of the group. Again, the red colour is an adaptation to life in the deep sea and in the dim light of the primitive world with its dense cloud canopy, for the red pigment enables the plant to absorb the green rays in which that light is rich. The ancient lineage of the group is further shown by the absence at the present day of primitive types in the red algae, and by the absence of motile reproductive cells as well as of free-swimming species. The brown algae 1 Phaeophyceael came next, according to this view, arising partly from brown flagellates and partly from red algae. That this is a younger group is indicated by the extra- ordinarily diverse structure of the reproductive organs, the constant presence of swimming reproductive cells, and the adaptation of the brown pigment to absorb r.aysfrom light more closely approaching that of the present world, but still with an atmosphere richer in water-vapour than that of to-day. In the meantime, the primeval red algae had become adapted to the dim ancient light, and therefore became restricted to the depths of the sea, leaving the upper waters as an open field for the evolution of the brown seaweed population w^hen the latter appeared. The green Alg.ae (Chlorophyceae) are the yomigest group of algae to appear in the succession. Their green colour is an adaptation to the clear light of later times, and they evolved in KNOWLl^DGK. 109 part from the recent flagellates and in part from the red algae. The early forms were marine, but after taking possession of the upper waters of the sea and invading estuaries, they became adapted to life inland in fresh water. Whether or not this ingenious theory of Brunnthaler's gains much acceptance among botanists, it must be admitted that it has the merit, conspicuously absent in various other specula- tions on the evolution of plants, of taking into account the probable conditions of life in ancient times. EVOLUTION OF THE FLOWER.— In the New Phytologist (1911. Nos. 5 to 8) there are two further instalments of the interesting paper on " Floral Evolution, with particular reference to the Sympetalous Dicotyledons," by H. F. Wernham. The first two articles in this series have alreadv been summarised in " Knowi.kdgi: " (1911, pages 231, 277). Engler's group Pentacyclidae includes the cohorts or orders Ericales, Primulales, and Ebenales. .After discussing the general characters of the Ericales (including the large family, or natural order, Ericaceae, and five other smaller families), we find the somewhat startling suggestion that the Bilberry tribe iVaccinioideae) should be removed from the Heath family altogether. It is true that the Vacciniiiiii tribe differs from the rest of the Ericaceae in having an inferior ovary, but in modern systems of classification (he position of the ovary is regarded as being of relatively small importance in deciding affinities, and it appears very unlikely that botanists will be inclined to follow Wernham in making even a separate family of Ericales for the Vacciniitm tribe, much less in regarding them as having had an entirely different origin. It is suggested that while the remaining Ericales probably arose from the ancestral Kanalian (Buttercnp-likel stock along the line which led to the Geraniales, the \'accinioideae had their origin from the line which led from the same ancestry to the Rosales. In a course of lectures on Systematic Botany which has recently been given in the University of London, and of which it is hoped to include a summary in " Knowledge " shortly, Dr. C. E. .Moss dissented from Wernham's theory regarding the position of the \'accinioideae, while agreeing warmly with his views on the evolution of the Gamopetalae in general, and pointed out that if the Vaccinioideae are to be severed from the Ericaceae, the Arbutus tribe (Arbutoideae) must necessarily go along with them. Since the two sections (Vaccinioideae and Arbutoideae) agree in all essential characters, excepting that the ovary is superior in Arbutoideae. and the .'Vrbutoideae are admittedly related very closely to the remaining sections (Ericoideae and Khododendroideac) of the family Ericaceae, the result of the adoption of Wernham's revolutionary proposal would be an unnatural and, in fact. chaotic arrangement. .■\part from this criticism, one can have nothing but praise for the careful and brilliant working out of Wernham's views regarding the origin of the various groups of Gamopetalae (Sympetalae) from different groups of lower Dicotyledons (.■Archichlamydeae or " Polypetalae "I. He. of course, adopts the theory that the Primulales have descended from the large group Centrospermae. which includes such well-known families as the Chenopodiaceae and Caryophyllaceae, and gives a '■ family tree '' illustrating the details of the descent according to his views. Here we feel on much safer ground, though further work on the development of the flower in the various families is. naturally, required before the detailed course of evolution can be traced. The Ebenales are less familiar to the British botanist than the two preceding cohorts, since this group consists almost entirely of tropical trees. The view is put forward, and worked out in some detail, that the Ebenales have arisen from the Parietales. hence the three cohorts dealt with are regarded as having arisen independently " by the grafting of sympetaly upon at least three archichlkmydeous stocks — the geranial, the centrospermal, and the parietalian." In his fourth paper, the author begins upon the large series of cohorts grouped under the name '" Tetracyclidae." in which the floral organs (sepals, petals, stamens, carpels) are each con- fined to a single whorl, as compared with the Pentacyclidae in which there are two whorls of stamens and therefore five whorls in all of floral p.arts. The Contortae comprise the families Asclepiadaceae, Apocynaceae, Oleaceae, Gentian- aceae. and so on, few of which occur in Britain. The ancestry and affinities of the Contortae present great difliculties — the floral structure is remarkably constant throughout the cohort and is of a relatively advanced character — and the Contortae " have left no traces of their progress from polypetaly to sympetaly in the shape of pentacyclic forms ; neither a second staminal whorl nor any hint of it ever occurs." Still, it is suggested that the group may have arisen from the Geranial stock, like the Ericales. " While the latter have employed their evolutionary powers, so to express it, in the direction of specialization of habit and details of floral structure, the Contortae have reserved their efforts for the realization of the economy tendency." In tracing the detailed affinities of the Contortae, Wernham points out the isolated character of the two orders Oleaceae and SaKadoraceae, which agree with each other and differ from the remaining famiHes of Contortae in so many striking respects that the author is led to regard them as deserving the rank of a special cohort, for which he proposes the name Jasniinales. cm-.Mi.srRv, By C. Ai.NSWORTii Mitchell. B.A. (Oxon.), F.I.C. CANADIUM: A NEW ELEMENT.— .\n account of a supposed new element, to which the name of " canadium " has been assigned, is given by Mr. .\. G. French in a recent issue of the Chemical News (1911. CIV, 283). It was discovered in association with platinum and other metals of the platinum group, in the trap-dyke of the Nelson District of British Columbia, its quantity ranging from a few grains to about three ounces per ton of its companions. The new metal, which is found in the form of grains or scales, is white and possesses a brilliant lustre. It melts at about the same temperature (964° C.) as silver, and is not so hard as platinum, ruthenium, palladium or osmium. Like platinum, it is not altered by being heated in the air, or by exposure to a moist atmosphere. It is not affected by iodine, hydrogen sulphide or solutions of sulphides, but is dissolved by nitric or hydrochloric acid. Unlike silver, it is not precipitated from its solutions by alkali chlorides or iodides. PHOTOGRAPHIC EFFECT OF CHEMICAL RE- ACTIONS.— .A discovery, which appears likely to have far- reaching effects, both in theory and practice, is described by Messrs. Matuschek and Neiming in the Clieiniker Zeituiig (1912, X.XXVI. 21). It has been found that chemical reactions of the most different kinds produce light waves, or that part of the heat energy developed during the re-action is transformed into light energy. In the striking series of experiments described, a beaker, to the bottom of which was fixed a star of tin-foil, was placed upon a sensitive plate in the dark, while the interacting sub- stances were placed within the beaker. .After several hours the plate was developed, and in each case a sharp image of the star was obtained. F"or instance, strips of various metals, such as zinc, copper, tin and lead, were suspended in sulphuric, hydrochloric or nitric acids, and notes were taken of the periods of exposure necessary to obtain sharp outlines of the star. The distance of the reacting bodies from the sensitive plate and the nature of the surface of the metal had an influence upon the results : and the smaller the chemical affinity of the acid for the particular metal, the less the intensity of the photographic action, and the longer the time required. Thus, in the case of the metals and acids mentioned above, four days were necessary to obtain a sharp image in the reaction between lead and nitric acid. The treatment of copper oxide or hydroxide with acids, or of caustic alkali with water, gave analogous results. A thin layer of quicklime or of calcium carbide when spread on a glass plate with a device of tin-foil 110 KN()\\I.1-,1)C,|- March. 1912. bi'iii'.illi and then IriMlcd with w.itcr. proved siiiiil.irly c.ip:il>li- of .iflci-lint,' llic plioiii^jiapliic pl.ito. The formation of tlir socalied ainnioiiimn anialK.ini also developed the ;ictivc rays, while the decomposition of sodium mctasiUcate by means of acids proved surprisingly rapid in this respect. Fven in the reactions taking place in the hardeniuK of Portland cement or in the setting of plaster of Paris and water, excellent inla^;es were produced in about three days. These experinienis sufjfjest the possibility of devising an ex.ict photographic method of measmiug and comparing the velocities of difterent chemical reactions. They may .ilso atTord an explanation why certain observers have found that rays emitted by the human body would affect a photographic plate in the dark, while others have been unable to confirm the occurrence of the phenemcnon. In the light of these experiments, it would not be surprising to find that the chemical reactions ceaselessly proceeding in the body should manifest their activity photographically much more rapidly in the case of one person than another. HLE.ACHING OF FLOUR .VNO ITS FFFIXT ON DIGESTION. — The late.st addition to the controversy as to the harmlessness or the reverse of the artificial ageing of flour by means of bleaching is the paper contributed to the J. III,!. Rnt>. Clicm. (1911, III. 912) by Messrs. Wesener and Teller. Of the various methods that have been proposed for bleaching flour, only those in which oxides of nitrogen are employed have proved commercially successful, and experi- ments upon the digestibility of the treated flour have therefore centred upon the latter. In the present commimication the results, which are given in detail, show that nitrites do not interfere with the digestion of starch by diastase, even when present in the proportion of 0-1 per cent. Nor is the process of pancreatic digestion checked either by nitrites in a relatively large amount or by protein which has been treated with nitrous acid or nitrites in not excessive quantity; while in peptic digestion nitric or nitrous acid may take the place of the hydrochloric acid natur.iUy present. At the same time attention is drawn to the fact that it has never been proved that commercial bleached flours contain either nitric or nitrous acids, or mineral nitrites, and that, hence, results obtained with these acids and their mineral salts are not necessarily conclusive. .Apparently, however, the oxides of nitrogen enter into direct combination with the colouring matter of the flour during the bleaching process, and the resulting compound gives the nitrite reactions. Physio- logical experiments have shown that the compound is not poisonous, and that it has no perceptible etfcct upon the blood P.ARAFFIN OIL FROM A YORKSHIRE COAL SEAM. — There are few recorded instances of the occurrence of paraffin oil in British coal seams, and the chemical compo- sition of the oil in these cases has seldom been ascertained. Particular interest thus attaches to the account given bv Dr. Cohen and Mr. C. P. Finn (/. Soc. Clieiii. Iiid., 191 i. XXXI, 12) of the oil discovered in a seam in the Hemsworlli Collieries, from the position of its occurrence and its bearing upon the theory of the form- ation of petroleum oil. The oil was found in the Haigh Moor scam at a point six hundred and ninety yards from the surface, where the road from the bottom of the pit crossed a fault which displaced the strat.i in a downward direction to a (maximum) extent of eleven feet. Subsequently more oil was discovered in a drift made early last year, the strata about the line of the fault being satu- rated with a yellow liquid, which became dark brown on exposure to the air. These strata, the position of which is indicated in the accompanying diagram, consisted of blue stone bind interspersed with Figure 108. ironstone b.inds, and intersected with soft white sandstone. Apparently there had been no formation of natural gas at this point. Tiic oil collected for examination was a d.irk brown semi- solid m.'iterial, which on fractional distillation yielded a series of fractions r.inging from a light mobile yellow oil boiling below 150 C. to semi-Sf)lid dark yellow products boiling above 300 C. The constituents of these fractions were very similar to the hydrocarbons of petroleum products of high boiling- point and suggested a coinnion origin. Possibly the oil had been formed in strata beneath the coal seam, and, finding its way through the fissure of the fault, had condensed in the cooler upper strata. Nothing in the nature of the coal itself pointed to its being the source of the oil, nor were there any signs of the intrusion of igneous rock, which in the heated condition might have caused destructive distillation of the coal. .Assuming this oil to have a petroleum origin, a difficulty is created by the absence from the strata of any fish remains, such as are usually associated with the occurrence of petroleum. Possibly deposits of cannel (in which aquatic remains are frefpiently found) might have had some connection with the formation of the oil. Vet, although there were such deposits in the vicinity of the coal seam, the oil was only found in the neighbourhood of the fault. GEOLOGY. By G. W. TvKRELL, A.R.C.Sc, F.G.S. EROSION IN THE HIMALAYAS.— In addition to the ordinary agents of denudation, others more irregular and abnormal are brought into play in great mountain regions. Dr. .Arthur Neve enumerates three of these exceptional factors in a paper on Himalayan Erosion iOeo^r. Journ.. October. 1911). Many of the great valleys of the Western Himalayas contain huge ancient riverine or glacial deposits, two thousand to three thousand feet thick, through which the present rivers have cut their way. This material is so loose and unstable that even in a dry climate, such as that of Lower Baltistan and Gilgit, landslips are constantly occurring ; while torrential rains, as may be imagined, have an enormous etTect in this direction. The erosion due to the landslips themselves is supplemented by that of floods caused by the cataclysmal outbreak of water dammed up by landslip debris or" by glaciers. These floods cause tremendous erosion in the main valleys. Some sixty-nine yejirs ago, according to one account, a vast landslip blocked the Indus river below Bunji. submerg- ing the valleys for a length of thirty-six miles. A similar block, this time due to glaciers, occurred in the Suru valley in 1896. The burst, when it came, devastated the fields and villages for forty miles below. The last of these abnormal factors of erosion is the effect of earthtjuakes in initiating the operation of landslips and floods. In the earthquake areas of the Himalayas, the soils of the hillsides and plateaux are split and crevassed, large and small landslips happen, drainage is thereby diverted or blocked, and the streams later burst out with destructive force. Dr. Neve gives an impressive picture of the enormous erosive forces at the command of nature in great mountain regions such as the Himalayas. NEPHELINE SYENITES OF WEST AFRICA.— The region of Christiania, described in a classic memoir by Briigger. and noted for its richness in rare minerals associated with alkaline igneous rocks, has a rival in the .Archipelago of Los. situated close to the shore of French Guinea on the West Coast of .Africa. The islands, three in number, consist of masses of nepheline syenite with their usual s.atellitic asso- ciates— tinguaites,essexites,theralites.shonkinites.camptonites. and monchiquites. These are fully described by Lacroi.x in a finely illustrated memoir. " Les Syenites Nepheliniques de r.Archipel de Los et leur Mineranx" tXotiv. Arch. d. Miis. Paris (5) iii, 1911). In addition to a rich series of rare minerals, such as astrophyllite, riukite. wiihlerite. endialyte, catapleiite. and pyrochlore. usually found .associated with March, 191J KNOWLEDGE. Ill iiepheline syenite, Lacroix describes two new minerals : villiaiiiiiitc (sodium fluoride), of a violet or carmine-red tint, supposed tetrogonal sj-mmetry, and soluble in water ; lositc. a mineral allied to cancrinite, but differing from it in several particulars, notably in lesser birefringence. .\s no associated strata are known, nothing can yet be determined as to the geological age of this alkaline series. On the adjacent mainland of French Guinea there occurs a totally different series of rocks, consisting of hypersthene granite (charnockite), norite, gabbro, and peridotite, a series which has much in common with the charnockite rocks of India. CRYST.-\LLIZED TURQUOISE.— Hitherto the turquoise has never been found in distinct crystals. It has always been opaque and massive, usually of a green colour, only the best qualities shewing the well-known blue. It is found in irregular masses filling up cavities and fissures in the mother rock. .An occurrence from Virginia (Schaller, Aiiicr. Joiirit. Science, January, 191 2t, however, seems to show that turquoise may sometimes assume a definite crystallized form. The specimen consists ot irregular fragments of glassy ijuartz cemented by thin layers of turquoise crystals. On each side of the specimen is a drusy. botryoidal layer, bristling with minute crvstals of a bright blue colour. Their density is 2-84. and whilst their smalliiess rendered their crystallographic determination difficult, it is believed that they have triclinic symnietrv and are isomorphous with chalcosiderite. A chemical analysis gives the following result : — P.O, 34-13 .\i,0:, 36-50 Ke,0:, -21 CuO 9-00 H,0 20-\Z 99 • 96 The fornmla derived from the ratios of the analysis is CuO, 3 .-M-O;,. 2 FaOo, 9 H.>0. The above analysis agrees very closely with one by Penfield on very pure massive material from Nevada. The correct formula for chalco- siderite is similar to the above, with the substitution of iron for aluminium. Moreover, its crystal-angles are \ery close to those tentatively given for the minute crystals of tunjuoise. Consequently there is a strong probability that the two minerals are isomorphous. METEOROLOGY. By John A. Curtis. F.R.Met.Soc. The weather of the week ended January 20th. as set out in the statistical tables issued by the Meteorological Office in the Weekly Weather Report, was wet and unsettled. Snow or sleet was general during the earlier days of the week, and the falls were heavy except in the Southern parts of the country. Temperature was above the average in Scotland, N., the southern parts of England and in Ireland, but below it else- where. The \ariations, however, were nowhere \ery large. The highest of the maxima was 57" at Fort Augustus, on the 17th. In Jersey the highest reading was 52°. Readings of 50 or upwards were reported in all districts except England, N.E. and E..and Scotland, W. The lowest reading reported was 18' at Balmoral on the 20th. but temperatures down to 22' were recorded at several other stations. In Ireland, however, the temperature did not fall below the freezing-point, and in the English Channel the minimum was 35". The lowest reading on the grass was 15 at Balmoral. Rainfall was in excess of the average in all districts except Scotland. N. and Ireland, N. The wettest district, relatively, was the Midland Counties, where the recorded fall was nearly four times as much as usual. .At Birmingham the total fall was more than five times the average. 2-22 ins., as compared with the average of 0-44 in.' Sunshine was in defect in all districts, and at every individual station except two, Markree Castle and Scilly. The last-named station was the sunniest in the British Islands with a mean daily duration of 2-0 hours or 24%. At Westminster the week was sunless. The temperature of the se.a water round the coasts varied from 37° at Scarborough to 50° at Scilly and Salcombe. The week ended January 27th was dull and r.ainy in the southern districts, but mostly fair elsewhere, but with much mist or fog at many English stations. Temperature was below thie average in all districts except the English Channel, and in many parts the deficiency was considerable. The highest readings of the week were 55 at Bettws-y-coed and 53 at Killarney. In the English Channel the maximum was 52', but in most of the districts the maxima failed to reach 50 . The lowest readings were 18' at Balmor.al and 21" at Poltalloch. In the English Channel the minimum was 39 , but in every other district sharp frost was reported. On the grass the lowest readings recorded were 15 at Balmoral and Hillington. and 17 at Newton Rigg, Llangauimarch and Markree. Rainfall was above the average in England, N.E., E. and S.E., the Midlands and the English Channel, but was in defect elsewhere. The defect in many cases was extreme, and at some stations the week was rainless. In Ireland, N. the mean for the week was only 0-01 inch as compared with an average of 0- 81 in.. and in Scotland, N. the mean was 0-11 in., the average being 1 • 63 inches. Sunshine as a rule was in excess in those districts where rainfall was i!\ defect. The sunniest district was Ireland, S., with a mean daily amount of 2-3 hours (28%). Scotland, N., with a mean of 1 -8 hours, was 12 % in excess of the average, while the English Channel, with a daily mean of 1-9 hours, was 4 % below. At Westminster, the daily mean was only 0-2hours (2%t. Themean temperature of the sea waterranged from 40-0 at Burnmouth and Cromarty to 48-4 at Scilly. The week ended February 3rd was very cold, but dry and sunny. Temperature was below the average in all parts, the deficiency aminmling to as much as 10°- 1 in the Midland Counties, and to 9-7 in England, S.W. The highest of the maxima was 49' at Waterford, but at many of the stations in the Midlands and England. E., the maximum for the week was under 40°. In the English Channel 47^ was the highest reading recorded, at Guernsey, on January 30th. The mininia were 15° or below in every district except the English Channel where the lowest reading was 28°. The lowest readings were 4" at Balmoral on the 2nd, 9 ' at Llangammarch and 10° at Fort .Augustus. On the grass readings down to zero were recorded at Norwich, Balmoral and at Burnley. Rainfall was light very generally, and was below the average in all districts. Indeed, over a large part of the country the week was practically rainless ; thus, in England, S.W. the mean total for the district was 0-01 inch, the average being 0-82 inch. Bright sunshine, on the other hand, was above the normal everywhere, the excess reaching 30% in the English Channel, where the mean daily duration was 5-2 hours or 57% of its possible duration. The advantage of the suburbs as regards duration of sunshine is strikingly illustrated by the figures for this week, the mean daily duration being at VVestminster 0-5 hours (6%); at Camden Square 2-6 hours (29%l, but at Hampstead 3-7 hours (42%). The mean temperature of the sea water varied from 37°-9 at Scarborough to 47°-8 at Plymouth. The week ended February 10th was at first \er\' cold, with snow showers in nearly all parts. .After Monday, however, a thaw extended over the country from the southward, the air became humid, and rain was frequently experienced. Tem- perature for the week was below the average in all districts except the English Channel, where it was very slightly above. Maxima above 50 were reported from all districts, the highest readings being 56" at Bath, Clifton and Llandudno. The lowest readings were on the Sunday or Monday, and were below 17 in all districts except the English Channel, where the minimum was 27". The lowest reading reported was — 5t at West Linton, on the 4th, or 37" below freezing-point. At Balmoral a reading of —Z' was recorded on the 5th, and a Gordon Castle the minimum was 1" on the 4th. On the grass a reading of —7 was recorded at Crathes. Rainfall, though but little more than one third the average amount in Scotland, N., was in excess in Scotland, W., and in 112 KNOWI.I Ix'.l MaK(II. 1912. Ireland. S. In the other districts it was generally in excess, thiiMKli the departmis from the tnean were inconsiderable. Sunshine «as sli(;htly in excess in Scotland. N., and in England, N.W., but was in defect elsewhere. In Scotland, W., the daily mean was only ()-6 hour (7%). The sinmicst station was dreat Yarmouth, where the daily mean was 3-0 hours (40 %l. .At Westminster the duration averaged 0-9 hours (10 ",.•; at Hampstead in contrast with the previous week the aver.ige was less, 0-fi hours(7 ",. ). The mean temperature of the sea water ranged from 36° -2 .it Croinarty to 45' -8 at Salcombe. MICROSCOPY, conducted with the assistance of the following iiiicroscopisls : — AuTHiR C. Hankibi.I). Arthur Eari.anii, K.K.M.S. Richard T. Lewis, F.R.M.S. Chas F. Rousselbt, K.R.M.S. D. J. ScoiRHELD, F.R.iM.S. C. D. Soar. F.I..S.. K.K.M.S. The Rkv. K. \V. B(im James I',i;rton. Charles H. Caffvn j# £ X) LOWPOWKK PHOTO- MKKCU.K.VPHV WTIH- OL'T A MlCKOSCOl'i:.— This note is chiefly con- cerned with home - made contrivances of a very simple character, designed to be of service in simple low power photomicro- graphy. By this latter term is meant that region of work between the ordinary copying " of everyday photography, and the more .1 m 1) i t i o 11 s angiiioiitatioiis which necessitate the use of a microscope as well as a camera. In this chapter a microscopt is not used, but con trivances are shown which enable us to \isc ordin.iry micro-objec- tives of low power, i.e., an inch or so. When lenses of foc.il length not less than two inches (say tw^ • to four inches range are to be employed with any ordinarx quarter -plate camera of, say. twelve inch bellows Icngtii. it is clear that we cannot get any very great magnification or ratio of image to object, li "ill. Ilicrcforf. be desinililc to .nis^ment tlie Figure 109. camera length in some way. One convenient plan is by the use of a mi^tal tube, one end of which screws into the ordinary camera-lens flange, the other end cut with a similar thread to take the lens to be employed. It is a further convenience to have this tube in two pieces AB and CD. as shown in Figure 109, so that we may use one or both pieces according to our desired degree of magnification. The end A screws into the flange on the camera front, B and C join up together. D is here closed by an " adapter " to take any ordinary micro-objective. E is a two-inch Zeiss protar with lens cap F. The size of this particular tube is large enough to take a Wray four-inch U.K. or \V ray three-inch platystigmat, both exceedingly useful tools for natural history work, e.g., insects, fossils, shells, parts of plants, and so on. Lenses of these kinds are already provided with stops or diaphragms, but when the worker is using ordinary long focus te.g., two-inch) micro-objectives, it is often of very great service to use also a contrivance known as a Davis shutter. This is shown in Figures 1 10 and 111. where we see the two sides of the micro-objective adapter that was similarly lettered in Fig- ure 109, and also two views of the "Davis "which is really a separable iris diaphragm contrivance. As this cannot be put inside the lens it is screwed in to the adapter, 1. 1'., between D and the objective in use. The worker will find it very convenient to cut a card wedge showing points of width one-, two-, three-, and so on, tenths of an inch. This wedge is inserted into the iris which is then closed just to grip it and the pointer outside cor- respondingly marked one-, two-, three-, and so on. We can thus at any time close down the "pupil" to any re- quired size by means ofthepointerand scale. It should be remem- bered that the expos- ure normally will vary as the squai'esof these numbers. Thus, two- tenths diameter passes four times, and three- tent lis nine timcs.a.s much light as the one-tenth diameter opening. .V glance at the table will make matters clear in a moment. Sii])posi< the lart;cst ,iprrt:ir<' is half ,iii inch. ;.('.. five-tciitlis. R> ^ iM'.iKi: II. March. 1912. kxo\vli:dge. Numbers on scale, u-.. 10th of inch diaineU-r 1 2. 3 4 5 1 Area of opciiini,' ... 1 4 9 16 25 1 Exposure ratio (appro.x.l... 1 25 6{ 21 I'lGLRIi 114. Holders. — The nature of the object holder will necessarily vary with the nature and size of the object. 1 ijive two very generally useful forms. Fissure 112 shows us a small rather hea\y box to which are fixed two thin flat pieces of wood leg., bits of cigar box lid). To these, in turn, are screwed two ordinary wood spring (.American) clothes clips, which one may get by the dozen for a few pence at any " oil shop." This contrivance en ables us to hold any ordinary microscopi<- slide, as shown in Figure 112. F'igure 113 is a similar hea\y box used a> a base ; to this a pair of spring clips are fixed. These, in turn, grasp a pair of clean thin glass plates between which it is often convenient to " sandwich " such a thing as the flowering part of Poa ainiiut. and so on. Passing now to photographic arrange- ments, we have in Figure 114 one of the simplest contrivances imaginable — viz.. a flat, straight, thick, heaxy piece of wood, which serves as a baseboard on which rests \, an ordinary camera, with extension lens tube B, which requires a support C (shown in a subsequent figure, E 120). The object sand- wiched between two pieces of plain glass is held at E (in the contrivances shown in Figure 113). At R is a small circular mirror fitted up for use as a reflector, also shown in other figures. Some such simple contrivance as this may serve the care- ful and patient worker for occasional use, but it will be found that there is considerable risk of getting the parts out of position unless we have some read.\- means of fixing them to the baseboard. In connection with the plan of using a glass sandwich arrangement. Figures 113 and 114, it should be noted that there is in certain lightings a considerable risk of getting harmful reflections. To obviate this the following plan is efficient. To a piece of stout card (c.^*.. straw board) fix a piece of rough black cloth by means of paste oi glue. This card may be about eight by six inches'. \Vhen the paste is dry, cut a circular hole the exact size of the glass part of the lens, and in such a position that when the card rests on the baseboard this hole just coincides in position with the lens opening. FiGURi: 11. i. Such an anti-reflection contrivance is shown in working position, /.e., close up to the face of the lens, in Figure 114. I now pass on to a \'ery much more useful form of base- board. This, in my case, consists of a piece of teak about four feet long, two and a-half inches wide, and half an inch thick. This is firmly fixed by means of an ordinary camera screw (A, Figure 1161. which loosely fits the central hole of the tripod top, but its thread engages with the wood of the baseboard. •The camera is fi.xed to the baseboard by a second similar screw, B. The object is held in a holder, D, to be presently described, while E is a mirror reflector. At C is shown a piece of card covered with black cloth. This is used for making the exposures. It is here shown to be leaning up against the objective, which in this case is conjoined with the Davis diaphragm. The advantages of this system are porta- bility. I.e.. we can move the whole thing about together so as to get the object in a favourable lighting, and it is remarkably free from the efl"ects of vibration, any disturbance of the floor causing the whole contrivance to vibrate as one thing. Next a word as to the object holder. The general arrange- ment will be made sufliciently clear by a glance at F"igures 1 15 and 117. The former .shows that this apparatus is made to slide along and yet grip the baseboard along its edges. Figure 1 1 7 shows how the two holding springs are fashioned out of pieces of an ordinary steel knitting needle. This is made red hot in a gas flame and then gently bent to the shape shown by the aid of a couple of pairs of pliers. When piercing the sight hole in the holder (Figure 115) it is important that its centre is just opposite the centre of the lens extension tube. This will be found of help when getting the object slip into position, and also in getting the axis of the camera parallel to the baseboard. In Figure 118 we see a back view of the mirror and its mount. The mirror is about four inches in diameter, and has a thin metal rim-frame. .\ semi-circular hole is cut out of the thin flat piece of wood A and the mirror swung by two screws C, C — just tight enough to hold it at any desired angle. At B a small block of wood is .added to give weight and firmness and prevent the whole thing being top-heavy. In Figure 119 we see the front side of the mirror holder and should note carefully a small circular peg or dowel in the front edge of the holder. This engages with an easy fitting hole in the baseboard and enables the holder to be turned about a vertical axis through this dowel or peg, while the two side screws C, C give us a horizontal axis ; thus we can set the mirror at any angle by combining these two movements. I now come to the last bit of home-made FlGUKt 110. 114 KNOWI.I.DGI. Makcii, 1912. I'lGURK 117. coiitrivaiicr for this note, which is shown in I'ig- nre 120. At A and 15 wc have two ordinary photo- graphic lenses, A and H, both of fairly short focal lent;th, vis., four and three inches. It was pro- posed to combine the two in tandem fashion by means of a brown paper tube. D. but as lens B was somewhat sm.ilier than lens A. lens B had to have its dia- meter brought up to match that of A by means of an extra bit of tube, C. These card tubes are easily made of brown paper strips and office paste, using the lens tube as a roller. but remembering that the paste-wetted paper will contract a trifle, the lens tube should be covered with two laps of thick, smooth writing paper. Without this you may find your tube too tight when it is dry. Talcing the diaphragm distance as the nominal "separation," we can apply the usual rule for finding the com- bined focal length of the four and three inch com- ponents. First multiply four by three, getting twelve. Now add four to three, getting seven, and substracting the dia- phragm distance or "separation." say one inch, we get six. Finall> . dividing twelve by six %m get two inches as the focal length of the whole sys- FkH'KI tem. As a matter of fact. this estimate was shown to be practically right, but the small- ness of the stops of one of the lenses gave an inconveniently restricted field. However, the idea is worth mentioning. Finally, Figure 121 shows this combination in use. Note the card support E, Figure 120, to take the front weight of the tube. We here get a side view of the object holder which, when combined with the front view of Figure 115, will enable this item to be easily made. The exposing black card S is shown, and also the reflector with its dowel-peg (cf. Figure 119) inserted in the baseboard. F. C. Lambert,"M.A., F.R.P.S. l-"lGlui-: US. KOYAL MICK(J- SCOHICAL SOCIFTY. February 21st. 1<)12.— H. (i. IMimmer, l-;s(|., I'.K.S., president, in the chair. Mr. E. J. Spitta, with the help of the projection Lantern, de- monstrated the principles which should influence the photographer in the preparation of negatives from which coloured lantern slides were sub- sequently to be made. Commencing with photo- graphs of the spectrum taken upon the various sensitised emulsions at present on the market, he pointed out the ne- cessity for the use of panchromatic plates. He showed a number of slides, macroscopical as well as microscopical, by means of which he contrasted the effects produced by colouring lantern slides made from ordinary plates with those prepared from panchromatic plates, and showed the wide possibilities which were opened up to the skilful artist. Mr. Rousselet com- municated the " Fourth List of New Kotifera since 1889" ii.e.. the date when Hudson and Gosse's Monograph of the Kotifera was com- pleted by the issue of the supplement. recording altogether four hundrtd species at that tiniei. The author explained ]](l that his three preceding lists, published in 1S9J. 1897, and 1902, contained three hundred and ninety-three new species, and the fourth list now submitted two hundred and fourteen names, a total of six hundred and seven new species since 1889. After making allowances for synonyms .and insufficiently recorded species, Mr. Rousselet estimated the present Rotiferous population of the world comprised eight hundred and fifty-seven species. .-V slide of Xaiiciilti socialis. presented by Professor T. Chalkley Palmer, was exhibited by the Society. This is a fresh water diatom, discovered by the donor in 1905 near Media, Pa. FlGURli 121, March, 1912. KNOWLEDGE. 115 A L'NIVEKS.AL ( .!.( )Mi: 1 KIC SI.lDl-: PH()T()-MICK( )GK.\PHIC .•\PP.\R.\TUS.— We are glad toyive in Figure 122 an illustration of a carefully designed piece of apparatus whicli Mr. J. K. Barnard described before the Royal Microscopical Society last November, and which he has now put on the market through Mr. Charles Baker. Extreme rigidity is obtained and it can be used with a vertical as well as an horizontal camera and with almost any type of microscope, whether it has a horseshoe or a tripod foot. .Ml the pieces of apparatus carried on the geometric slide are mounted so that they may be centri-d a.-' ii' .'. !- '■■ t!'- ■'t-'i'- ivi- of the instrumont. and !iia\- be clamped (]n\v\\ when once their positifni h:is been di'tcrniined. Figure 122. ORNITHOLOGY. By Hugh Boyd \V.\tt. M.B.O.L". .•\NOTHEK NEW BRITISH BIRD— THE COLL.\RED FLYCATCHER. — The addition of this species (Mnscicapa colluris Bechst.i, to the British list falls to be chronicled this month, two male birds having been shot in L'dimore Lane, near Winchelsea. on 12th and 13th May, 1911, respec- tively. This bird is similar in appearance to its near relative the Pied Flycatcher, but has a conspicuous white collar, well shown in the photograph given in British Birds for February 1912 (Vol. \', page 2381, from which the above particulars are taken. Its summer range is in south-east Europe generally, and it is very local elsewhere on the Continent. On passage it is known in most parts of Europe, Persia, Asia Minor and Palestine. It winters in Egypt. HYBRID GREENFINCH AND CHAFFINCH.— At the cage-bird show of the London and Provincial Ornithological Society held at the Crystal Palace. London this month (Febniaryl, much interest was aroused by a hybrid bird between a Greenfinch and a Chaffinch. Such a cross is stated never to have been known before, and the particular bird shown is described as small and slenderly built with brownish plumage, tinted delicate green in certain lights. In captivity, the Greenfinch will interbreed with the Canary, and in a wild state with the Common Linnet. THE LAST OF THE PASSENGER-PIGEON.— There now seems to be only a solitary bird (a female, about nine- teen years old, belonging to the .Zoological Society of Cincinnati) alive to represent the famous Passenger or Wild Pigeon iEctopistcs inifiratorius), which, within the memory of living man, bred in enormous numbers all over the forests of North .America. Wilson, the American ornithologist, estimated that a tlock seen by him consisted of more than two thousand two hundred and thirty millions of birds, and Professor Newton, in repeating this, says that the bird is "still occasionally to be found plentifully in some parts of Canada and the United States" \I)ictioiiary of Birds, 1893- 1896, page 696). Now, within twenty years, it has fallen to the very verge of extinction, and the great researches, recently made to find survivors in a wild state, have been quite unsuccessful. It seems likely 'that the Passenger Pigeon will soon rank with the Great Auk as an historical species only. The last living examples in the Zoological Gardens. London, were presented in 1SS3, one of w^hich survived till 1.SS9. In the Natural History Museum, South Kensington, there are twenty-one specimens of this Pigeon. The species is on the British list as a " doubtful " one, the five examples on record being looked on as introductions, although Professor Newton says that one shot in Fife in 1825 may have crossed the Atlantic unassisted by man {Loc. cit. page 697). THE FATE OF THE CAROLINA PARAKEET — Tills bird {Coiiiiriis carulinensis) seems destined to pass away in like manner to the Passenger Pigeon. In North America at the beginning of last century it ranged in sunnner as far north as the shores of Lakes Erie and Ontario, but before the end of the century its limits were curtailed to the Gulf States. .At the present date, except for some eleven individual birds in captivity in the United States, it has completely dis- appeared, In Europe, about thirty years ago, it was freely kept as a cage-bird, but it is improbable that there is now a living example on the Continent. The last specimen in the Zoological Gardens, London, died in 1902 and the last in the Berlin Gardens in 1904. HIBERNATION AMONG BIRDS.— A reviewer in the current number of " Knowleoge " (February, page 70), speaks of the theory of the hibernation of swallows as " long exploded." That it still exists in a nebulous way, and is considered worthy of investigation in well-informed quarters, may be seen by the statements made recently by Mr. C. W. Nash, biologist to the Ontario Government. He writes: "I have found evidence (of a sort) which leads me to believe that the Purple Martin and Chimney Swift may at times become partially dormant, and I have received recently from an eye-witness an account of the cutting down of a hollow tree near Peterborough (Canada) in the month of January many years ago. This tree is said to have contained hun- dreds of swallows in a dormant state, some of which were revived. I have the names of other witnesses of this curious incident, and am looking them up." This cannot be called conclusive evidence, but the result of the enquiries to be made will be awaited with curiosity. It may only be a coinci- dence and not in any way to be looked on as a corroboration, but the winter quarters of the Canadian Chimney Swift, one of the birds named, are not known. Such a fact shows how deficient we still are in complete knowledge of the localities and regular movements of even common birds, whilst, as regards the causes and reasons of migration, many of the theories and conjectures put forward seem to be as inade- quately supported by proof as is the theory of hibernation. \\6 KNOW I.I. i)r,i:. Makcii, 1912. .\ c"()Nvi:vi:i) n:Ki:(".KiNi:. — Oil ihc Mioini.ij; of 29lli Dccfiiihcr lasl a I'crtriiiic was foiiiul llyint,' ioiiikI diic of the looms ill the General I'ost Olhcc, ClasKow. hnl this pu/ziiiiK occurrence has been nicely explained hy Mr. John Paterson. He writes: — "When the S.S. Anchorin of the Anchor Line, on her maiden trip to Calcutta, had been in the Red Sea a couple of days, a hawk was seen on the top of one of the masts Keltinii; an assisted passajje on its southward journey in the wake of the migrating flocks from the north, on whom it naturally preys." The bird was secured by a sailor; and in a bo.v, fitted as a cage, " made the journey to Calcutta and (ilasgow, by way of some Italian ports." It was pre- sented bv the captain of the steamer to Mr. Paterson, in Glasgow, who was curious to exactly know what kind it was. He found it to be a ''young peregrine falcon .... or passage-hawk, the name falconers gave to a young bird caught during the season of migration." Having satisfied liitiis-lf. Mr. Paterson thought to give the bird freedom and accordingly let it ofl within the city of Glasgow. Such freedom as the ;itmosphere of Glas- gow may afford to a falcon was apparently not congenial, and the following morning found the bird in the toils again, as above mentioned. The case is a good illustration of how " casual " introductions may be made into our fauna, by man's agency. WADING HIRDS INLAXO ON MIGRATION.— In Kast Renfrew- shire a group of small upland reservoirs, of which Balgray Dam is the largest, has been long known to Clyde bird-men as a resort of waders and other water-birds. Mr. John Robertson, who has paid particnln attention to the locality, reports tli.n the autumn of 1911 was the be.i season there for waders in his ox perience of sixteen years. Tin- shortage in summer rainfall led to the exposure of so great an area of the bottom of Balgray Dam that passing birds were attracted to it as a feeding ground in greater numbers than usual. Mr. Robertson considers these birds to be making their way from the Forth to the Clyde ; that is to say that these dams are a point on a line of migration-flight across Scotland. The spot is not particularly favoured in natural situation and surroundings, being on the edge of the extensive industrial area of the lower Clyde valley, and almost in touch with suburban Glasgow, but no fewer than twenty-two species of waders have been noted there. Of these Mr. Robertson observed seventeen last autumn, from August to October. The movement began with the appearance of Ringed and Golden Plovers on 30th July, and the most noteworthy birds seen were the Turnstone, Curlew-Sandpiper (up to 20 in numbersl. Knot (up to 24), Ruft", Green Sandpiper. Greensliank. and Bar-tailed and Black-tailed Godvvits. In previous years the Grey Plover, Little Stint and Spotted Redshank had been seen. (John Robertson — The Glasgow Xaturalist, Novem- ber, 1911. volume IV, pages 7-10. Glasgow: John Smith & Son, Ltd.) Of the above-named, it may be remarked that it is quite exceptional to find the Turnstone, Knot, and the two Godwits inland in Scotland. PHOTOCik.Al'llV. By Edgar Senior. PHOTtJGR.VPIlING THE INVISIBLE.— Mysterious as the above title may appear, it has no connection with ghosts or spirit photography, but is merely intended to infer that, as \ Portrait takni witl far as the eye could discern, no light whatever reached the photographic plate. Such, however, were the conditions present, that plenty of rays which our eyes had no cogniz- ance of, were able to do so and act photographically upon it. As far back as 1801, Ritter, of Jeiia, proved the existence of rays having very powerful photographic properties occupying a region beyond the extreme violet end of the spectrum, which do not excite the organs of vision, and to which the iiaiiic ultra-violet is given. To Sir George Stokes we owe the dis- covery of how to make this region apparent. The beautiful experiment consists in placing a card, which has been coated with (luinine sulphate made slightly acid, in their path, when rays which were previously invisible at once shine forth, and the extent of the spectrum beyond the violet becomes apparent. That these ultra-violet rays have powerful chemically active properties is well known, their behaviour towards silver chloride bring of special interest. If a piece of fused silver chloride be placed in front of the slit of a spectroscope, the light that passes through forms a spectrum apparently unaltered in range from the ordinary one. but if a card coated with a solu- tion of (juinine sulphate be placed in position beyond the violet no effect is produced, the invisible rays appear entirely absent ; but the removal of the slab of silver chloride at once makes them appear, and from this we gather t hat the silver salt has absorbed them, and that chemical action will consequently take place in this region. In fact, the violet and ultra-violet rays .'lie the most active upon silver salts generally, as well as those of iron, uranium, chromium, and so on, and to such an extent is this the case, that formerly the violet end of the spectrum was regarded as the seat of chemical energy, and the name actinic rays applied to that region. This, however, can no longer be the case, as all parts of the spectrum are actinic, accord- ing to the nature of the sensitive compound employed. The idea of taking advantage of the sensitive iiess of silver salts to these rays of short wavelength, and so obtaining photographs of things invisible to our eyes is almost as old as plioto- graphy itself, for we find the suggestion of the experiment outlined in the " Pencil of Nature," published by Fox Talbot in KS44. .•\fter describing the production of a solar spectrum and the effect produced upon a sheet of sensitive paper by the rays beyond the violet "whose existence is only made known by the chemical action they exert," he suggests the possibility of separating them from the rest by passing them through an aperture into an apartment, or room, and so filling it with invisible rays, when, if a camera were so placed as to point in the direction of any objects, photographs might be taken by moans of the action of the in\isible radiations upon the sensi- tive plate. Talbot thus believed that it would be possible for a person seated in a totally dark room to have a portrait taken in the ordinary manner, or, in other words, that we should be able to photograph the invisible. The very fascination of the subject induced the writer. " some years ago now," to experiment in the direction indic;itcd. with the result that among those photographs produced in this way that of greatest interest " from its close connection with the ideas of Talbot," is the one that is reproduced abo\e to form Figure 12i. Although not carried out in quite the same manner as that suggested, the principle remains the same, as only those dark rays which exist beyond the violet were utilized, .ill visible light being cut otT by means of a screen devised by Professor R. \V. Wood combining a piece of cobalt blue glass \"iolet Ravs. March. I'Jli KX(3\VL1:DGE. 117 with a film dyctl with ;i solution of Nitrosodiinethylaniline. N O Co Hjv^ which allows oiilv ultra-violet ravs to pass N (CH,), through. To ilhiniiiiate the sitter, an arc light was employed and the exposure with a rapid plate was five minutes. The sharpness of the imase is not all that might be desired, but this is no doubt due to the difficulty of ascertaining the correct focus, together with the want of correction of the lens (a portrait onel for these rays. Considering that the lens and screen employed were composed of glass, the results obtained are remarkable, as this material is very opaque to ultra-violet rays : so that, as suggested by Professor Wood, quaitz. which is e.\ceedingly transparent to these invisible rays, should be employed instead, and lenses made of this material on the surface of which a thin film of metallic silver has been chemi- cally deposited to such an e.\tent that there is complete opacity- to visible light and only those rays between three thousand and three thousand two hundred transmitted. A great peculiarity about photographs taken iti ultraviolet light is the absence of strong shadows, and the rendering of some white flowers almost black. .Again, their action in causing fluorescence \v kIdw was due to the cotMbinatinn of nitric oxide and o^oiic after the passaKe of the discharge which formed these substances from the air passed through. Hut the explanation was not (jnitc satisfactory, because it was found that o/one from a Siemens' o/onisiiiK apparatus was not made capable of ^ivinn the ^;low by mere rarefaction in presence of nitric oxide. Professor Strult finds, however, that the cause of this is the low concentration of o/one produced by such methods; for on condensing out the ozone as a blue explosive li(|uid and then lettinj; it vaporise into a vacuum, and trealitiK it with a small quantity of nitric oxide, the kIow is at once produced. He thus shows that the discharge in r.irefied air produces a very considerable percentage of o/one. The intermittent discharge passed through air at ordinary pressure and especially at slightly reduced pressure gives a yellow tlanie with a sharp apex considerably above the curved path of the electric current through the air. This flame is the glow produced by the combination of nitric oxide and ozone. Oxygen itself gives a glow of a pale whitish aspect. It has been long a question whether this is due to impurity or not. Professor Strutt was able to demonstrate that the glow is due to water vapmu- as an impurity in very small ciuaiitity. If a wire connected to a Leyden jar be coiled romid a glass bulb containing rarefied pure oxygen, the afterglow can be produced by the clectrodeless ring discharge ; but if a fine tube connected to the bulb be immersed in liquid air, the water vapour is condensed out and the afterglow is extinguished. The electrodeless ring discharge has been recently investigated in the Cavendish Laboratory at Cambridge. It has been found to be useful in distinguishing the presence of gases in small (piantities as impurities in another gas, the masking etTcct of one spectrum on another being less apparent in the case of the electrodeless discharge. Various spectra are obtained under different pressures, and different intensities of discharge, these being peculiarly evident in the case of argon, which gives either a red or blue glow under the different circumstances. (See Donaldson. Phil. Mafi.. October. I'Ul.) ZOOLOGY. By Professok J. Arthur Thomson, M..A. WHALES' HAIRS. — .Although hairs are reduced to a ininimum in Cetaceans, there is probably no species entirely without them. Dr. .Arnold Japha has recently studied five baleen whales and six toothed whales, and has found hairs about the lips of them all. Apart from their great reduction in number, they show distinct signs of retrogression. The hair-muscles and glands have gone, the hair-shaft is greatly reduced, the root-sheath is simpler than usual, and there is no hair casting. On the other hand, there is very interesting specialisation, notably in the rich supply of nerve-fibres and in the way these end in the hair-follicle. There may be four- hundred nerve-fibres to one hair, so that if there are twenty-five hairs on the chin there are ten thousand nerve-fibres on a small area. In the toothless Cetaceans at least it seems highly probable that these sensitive hairs play a role of some importance in food-getting. KICPKOIHCTION OF BROWN RATS.— The economic and medical importance of the brown rat makes it particularly desirable that we should know as much about it as possible. Newton .Miller has furnished some precise data as to the details of reproduction, — based on the study of rats in captivity. The creature breeds all the year round. The young are carried from twenty-three and a half to twenty-five and a half days before birth. The number in a litter varies from six to nineteen, with an average between ten and eleven. Five or six litters may be actually re,ired by a single pair in the course of a >'ear. If the young are destro\ed or renio\ed at birth, there m.iy probably be a litter every month ; in one case seven litters were produced in seven months by one female. There is very little in the way of courtship. Smell seems important in sex recognition. Males fight persistently with one another and the conquered afterwards try to elude the victors. The females may, and usually do. resist the males for a little while, but they soon give up the contest. .'\fler the fighting period, males will often permit themselves to be severely punished by the fem.des without injuring them. Brown rats in captivity eat almost fifty per cent, of their young at birth; and mostly, if not always, the females are the culprits. They do this even when apparently undisturbed, and even when they are getting meat in their diet. The expl.'ination remains obscure. Brown rats .-ire not full grown before eighteen months, but sexual maturity is reached by both sexes not later than the end of the fourth month. RESULTS OF IMPRISONMENT IN DARKNESS.— J. Ogneff kept gold-fishes in a roomy tank and with plenty of food (earthworms and Cliiroiioiiius larvae), but in absolute darkness. He kept it up for over three years, and then observed the modifications that had occurred in the fish. The colour first became black, but after the second year it became golden again, and the reason for this is interesting. In the first instance the dark pigment-cells spread out, and covered up the subjacent layer of crystals which gives the gold-fish its golden sheen. In the second instance the phagocytes devoured the dark pigment-cells and thus re-exposed the golden layer. The changes in the eye were even more interesting. The structure of the pigment- epithelium of the eye was completely altered, and there was a complete disappearance of the rods and cones, and of some other characteristic layers of the retina. Profound atrophy of the eye occurred. The fish became totally blind. OgnefTs experiment suggests that an individual fish imprisoned in a perfectly dark cave would become blind. But it does not throw any direct light on the origin of a blind race of fishes in caves. DEFENCES OF BIVALVES.— Everyone is familiar with the elaborate outgrowths from the surface of some Lamelli" branch shells, which seem like a waste of shell-making material and energy. Mr. Cyril Crossland propounds a theory of their significance, — that they are often protective. In some species they are larger in the young forms and thev are of value during the relatively more active period when the young pearl-oyster, or Avicula, or Tridacna is crawling about and seeking a suitable place for settling down on. .An enemy like the shell-eating fish Balistes prefers those with weaker shells. .Another enemy, the boring Gasteropod .\Iurex. kills more of those with smoother shell. Thus it kills large numbers of Margaritifera maiiritii which has small and weak processes, but few ot Margaritifera margariti/era which has large strong processes remaining well-developed for at least six years. It seems that the strong processes prevent the Murex from readily getting a firm hold with its foot, and without this it cannot work the drill in its proboscis. Mr. Crossland explains how the Murex often kills the bivalve without boring. " It finds the flexible edge of the shell, then by contractions of its foot breaks a piece away. The mucus of the foot-glands is then poured out in quantities, and this has some poisonous effect, as the animal, while still untouched, ceases to respond to the stimuli which ordinarily cause a smart closure of the shell." SENSITIVENESS OF SEA-URCHINS" PEDICEL- L.ARI.AE. — In experimenting on the sensitiveness of a sea- urchin {Toxopneustes varicgatus) to a shadow cast upon it in the water, Dr. R. P. Cowles discovered a remarkable fact — that the snapping spines or pediccllariae react quite definitely even after being cut off from the body. There are two kinds, big and little, which respond differently to stimulus. One of each kind was placed in a large dish of sea-water, and exposed to direct sunlight ; the large pedicellaria opened its jaws, and the small one shut its jaws. When, however, a patch of shadow was thrown upon them, the jaws of the former closed while those of the latter opened. The change of the reaction resulting from a change in the intensity of the light stimulus was repeated many times with these two pediccllariae. The experiment proves that the pediccllariae act independently of the radial nerve, and confirms the view of von Uexkiill that the pediccllariae have the dignity of a reflex person. ■/-<"■■ >i pliol.-giaph Figure 124. Hallt-y's Cornel, May 4lh, 1910. In the dark night and clear air of New Zealand, the end of the tail seemed fully twice as wide as in this photograph. THE NEW ASTRONOMY. COMETS. Bv PROFESSOR k. W. BICRERTON. Thkik Occ.vsioNAi. .Ma(.xii-ki;nce. \\'hi:.\ one has seen Comets at tlieir greatest mag- nificence, there is no cause to wonder that during the long ages of ignorance these celestial visitants shoukl have l>een looked upon with awe and fear. Sometimes they seemed to be fiery chariots to carry the soul of the dead hero to eternal glory, or as portents of disaster to tell men to repent and to change their evil wavs. When a youth, I saw Donati's Comet as a vast luminous scimitar stretching from zenith to horizon, its vast dimensions d w a r fi n g everything. I remember how toy-like the trees and houses looked in contrast with the vast immensity of this superb FiGl.'KE 1 Diagram illustrating the path of the Comet. The dotted line represents the orbit of a comet. The diagram shows the radial direction of the tail from the sun, the retardation of its distant part into a curve. the Antipodes. Halley's Comet was still bigger than Donati's. .\t its best it subtended an angle of fully one hundred and ten degrees. In the early morning, as it rose, tail first, it had the appearance of a broad sil\er\- aurora springing up and covering a great w idth of the Eastern horizon. Gradually as it rose it narrowed and increased in intensit}-. It was many hours before the head came into sight and the whole majestic spec- tacle revealed itself. (See Figure 125.) When full}- in sight the dawn took something from its brilliancy, but even when thus diminished it was a memorable sight. Strange that its appear- ance should have been so insignificant in Eng- land. This may have comet. Then again, the same effect repeated itself w ith been partl\- due to the haze in the air. When one is first the recent visit of Hallev's Comet ; only as I saw it in in New Zealand, the extreme clearness of the atmos- 120 KNOWI.l.DCI. MAKtii. 191 ; pherc destroys one's capacity of juflj^'in/^ distances. Many a time I have asked tourists, wlio were standing on tile terrace of my ln)use, the distance of the Southern Alps; tlie answer seldom exceeded ten per cent, of the ei},'lity miles away. Nor do I think the idea that the Cralaxy orij,'inated in the impacts of two previf)usly existin},' sidereal systems would ever have occurred to me in lCii,t;land. I have been here nearK' one and a-half years ami have looked times without numher. yet never have I seen the outline of the Milky Way so clearly as to sugfjest the idea of that centrifugal motion that came with such over- whelming force to me as I examined the Southern sky. If we could join with other rational nations and bring about reduction of armaments, and then, if the i)eople of England, with a true imperial spirit, should act together with our overseas dominions, and with the price of a Dreadnought erect an observatory under those clear Antipodean skies, such an establishment would enable the many unsolved problems of astronomy to be ho[)efully attacked. Excuse the parenthesis, but the New Zealand skies are the true field for celestial observation. FiNDINc; ("oMKTS. The keen artistic eye of the astronomer readilv detects a change in the stellar pattern. Perchance he sees a new speck of light helping to fill a former void. " What is it ? "' he asks. Is it another [)lanet or an asteroid ? Is it a new star or a comet ? If it is a planet or an asteroid, it will probably be found auKjng the Zodiacal constellations in the plane of the ecliptic. If a nova, it will [jrobably approximate to the plane of the Milk\- Wa\', and occupy a permanent position among the stars. If a comet, it ma\' be anywhere : but because m-iny of the periodic comets have been caught by the entrapping action of the |)lanets, those whose orbits approach near the Sun will tend to aggregate towards the plane of the ecliptic. .•\fter a time, our astronomer, who has detected the new spot of light, finds it changes its place among the stars of the constellation ; hence it is not a nova. If it begins to show a considerable and hazy disc, with a distinct nucleus, it is probably a comet. Then as it approaches the Sun a tail generally appears. It has now all the characteristics of a comet, and so is declared to be one by the astronomical world. Then many other optic tubes are directed to further study its character and to plot its orbit, to photograph its form and stud\- its spectrum. Normal C'omkts. Let us now examine what the countless observa- tions of the astronomers and spectroscopists ha\e to tell us of the salient characteristics of a normal comet. Then we will use our powers of induction and deduction on this assembled set of observational facts, and, using also the accepted physical forces and laws of nature, try and formulate an explanation of the wonders of normal comets and treat further these explanations in the light of those that show abnormal characters ; remembering always that it is the normal that is our true study as regards comets or any other special [ihenomena which we are attacking. The abnormal we must use as being chiefly of value in tending to reveal undiscovered cosmic forces and unrevealed laws of nature, such as have been so prodigally opened to our imagination within the last decade or so. Let us examine the normal comet and try to fathom its m\stery. .A NOKMAI. CoMKT. It consists of a nebulous star-like body or head, w ith an immense luminous plume or tail : the tail is frequently curved, it is not infrequently multiple, and where its several parts are unequal in volume the thinner portions tend to be the straightest. .\s the comet travels in its orbit, the tail is almost alwa\s directed away from the Sun. The tail is generally curved in such a way as to suggest a lag, as though the tail had been produced b\" an impulse. and the luminous effect had taken time to travel. The appearance of some comets is not altogether unlike a rocket, but the rocket leaves its tail behind it. whilst the comet travels with its tail side on. The nearer to the Sun the greater the tail grows to be. Figure 125 shows the normal character of a comet as it passes the sun in the perihelion i)ortion of its orbit. The drawings of man}- comets show a kind of series of parth' ensphering shells being projected from their heads towards the sun. TlCNlITV OK COMICTS. The liead even of a comet is of extreme tenuity, so that stars have been seen completely through some of them in their densest parts. Comets ha\e also passed in front of the Sun, yet no sign of any eclipse effect has been seen : nor e\en the slightest darkening has been observed. These two facts, combined with others, suggest that comets are of the character of a swarm of meteors. A comet has been known to part into two, and travel as distinct parts, and finally dissipate altogether. The Earth in its orbit intersects the orbits of some comets, and on the days of nearest approach the sky is lit up w ith a brilliant display of meteors, with an effect as though they shot in every direction from a radiant point. (See F'igures lib and 127>. Some of these displays have been of extreme brilliancv and beauty. .Astronomers and tra\ellers who have seen such phenomena at their best, describe them as of such superb grandeur as to out- shine the most magnificent pyrotechnic display. Those of us who have seen only ordinary examples of these exhiliitions. know how glorious e\en such sights are. Comets api)ear to shine by reflected light, but as their luminosity- often increases more quickly as the\- approach the Sun. then the law of the in\erse March. 1912. kno\vlI':dgk. i|uares suggests they probably become self-luminous might be expected : because even supposing fully si.xty per cent, of comets were hyperbolic, we might reason- ablv expect to appear to see ten or even fifty times as many that were not hyperbolic ; as once a comet is entrapped it will appear again and again, whilst an hyiierbolic comet comes once and goes for ever. Our solar system has probabK' had some scores of millions of years in w hich to entrap comets. Hence it is of supreme im[)ortance to very carefully look for hyper- bolic comets. The discover}' of even one in a lifetime would be important evidence, and tell us much of the origin of these bodies. .IS thev become subject to the Sun's tidal action and the heat of im[)act, and as the light of electricity proiiiirt-il b\' friction is developed. Tni: Mass of Co.mkts. Comets have approached very close to planets ami their moons, without any .listurbing effect having been able to be demonstrated : hence in a cosmic sense they cannot be of great mass. All the evidence suggests that they are small meteoric swarms, so small that they have been called " pinches of cosmic dust." But our earth has also been called " a speck of cosmic dust." yet we know its mass is far from insignificant. So with the comets. It appears to me that their real mass must be considerable ; for unless there were great mutual attraction, the Sun's differential pull on their several constituents must dis- perse them. Had the\" fully one-millionth the mass of the Marth it is probable that under tile conditions observed their perturbing action could not be measured. Vet such a meteoric swarin would have I mass of six thousand millions of millions of tons, iiid this I imagine is what we must accept to be the order of the mass of a normal comet. .Although the passage of the earth through a comet's tail has not been able to be detected when such an event has occurred, if the earth were struck by the actual nucleus of a comet. I imagine tile inhabitants would ha\e a very warm time, with possibly no one left to tell the tale of its temperature. Figure 126. The above diagram illustrates a set of parallel meteors, a part of a train, plunging into our atmosphere. The apparent radial direction is an effect of spherical perspective, as is also the lengthening of their curves, as they increase in distance from the radial point. Thk Sl'KCTRA OF COMETS. A good deal of conflict seems to exist as to the spectra of comets. There has alwa\s been a tendenc\- to ascribe much of their ob- served effect to carbon and its compounds. Professor I'owler has quite demon- strated the existence of carbonic oxide in both the heads and tails of some comets : but we require to know a good deal more than we do about comets' spectra. The SuKPRisiNc; \'akiety of the Phenomena Presented by Comets. The above are some of the more salient and characteristic properties of comets, but they are very ex- traordinary objects, and they teem with surprises and have extraordinary varieties of structure (See Figures 129 and 1 Jl) : so varied, indeed, that it looks as though a long time must elapse before all of even their generic characteristics shall be understood and receive a satisfactor\- solution. DiSTlRl'.ANCI-; AND DISTOR- TION OF Comets' Tails. The tails of comets not infrequently seem to be subject to a tearing or distorting action. They sometimes temporarih' s])lit into parts, or become irregular and roughly nucleated. They appear to he encountering some disturbing force in their passage through space. (See Figure 128). The Orbits of Comets. The orbit of the majorit\' of comets is either elli|)tic, or closely approximates to a parabola. This .A Meteor heated by friction of the atmos- phere and its volatiHzed train. It has not yet split or exploded. Meteors frequently do so, and the parts scatter. Dense Cosmic Masses. It is prettv clearly evident that comets are meteoric swarms, and it is almost certainly the fact of their fragmentary character that causes their brilliancy. It seems clear. howe\er, that single bodies of many times their mass might easily pass through our svstem without their being seen. \\'hen such a dense mass struck the Sim it w ould act as a detonator, that would cause the solar energy to develop a most surprising solar disturbance. EXPLANATION'S. W^ now trv to offer some tentative suggestions KNOWLI-.Df'.i: March. 1912. til account for some of tlic manifold diaractcristics of comets. .\s wc have already shown, it is fairlv well estahlisheil that they aie meteoric swarms. We will tiierefore try to deduce the jihenomeiia th.'it will ensue when suc-h ;i swarm apjiroaches the sun. The Comet 1908. III. September 30th, 1908, 47 minutes' exposure. Comefs tail showing distortion. particles composing the swarm arc almost cerlainK- kept in leash by mutual gravitation. Every meteor has an independent orbit. Almost certainl\- the constituents occasionaih collide. e\en in distant space. Suppose the swarm has approached the Sun. each particle is falling towards him independent!}' of the others, yet acted on by all the others. Some comets have passed less than a radius away from the Sun's surface. TIk parabolic velocitj- acquired by the fall of earli particle to this position would be of the order of close on three hundred miles a second. The near |)articles would he made to move enormously swifter than those at the distant jiart of the swarm. Everv orbit wduld be so disturbed that many of the outer ones would stray away from the general mass never to return. They would continue to move roughlv in the comet's orbit, not. however, by any means e.xactK- so. and a broad swath of meteorites would be i)ro- duced. If the comet were i)eriodic, the varied velocit\ of the particles would cause this field to e.xtend itself until the whole orbit would be more or less sj^read with the meteors. The crowd of particles would not only extend itself lengthways in the orbit, but would broaden also, gradually sjireading space with cosmic dust. It is this spread of material the I'2arth encounters that gives us the iiuninous radiant swarms. LUMINCJSITY OF COMETS. When a comet ai)|)r()arhes the Sun. the distmbing action of solar attraction would cause maiiv im|)acts. These wouUI temporariK' s|>read the swarm with gas and other resisting material ; this in addition to the heat of innumerable impacts would cause much friction and result in the development of electricitv. l?oth effects would produce luminosity, whilst solar radiation itself would be reflected. When the comet was near the Sun the latter would also be a great heating factor. Till-: E.\vi:i.()i'i:s. In a number of experimental investigations, I have shown that when matter carries off electricity' it tends to do so in pulses. The potential gradually rises until it produces disruption. This disruption [)roduces heat. This motion of heated molecules seems to possess the power of taking off electricitv, and lowering the potential almost or cpiite to zero. Then the potential commences to grow again until, once more, discharge takes place. Some such action as this may account for the partially ensphering envelopes that seem to be projected from some conict'^. Till. Tails oi- thi-; ("omkts. W'lieii we consider all the pli}sical facts, by no stretch of imagination does it seem possible to think that the tails of comets are material emanations pro- jected from the head. Is it rational to think of them as a kind of feather or material plume, attached to the nucleus, that swings around at the pace of scores of millions of miles an hour ? Or that it is made up of material particles, projected radialK' from the Sun the whole length of the luminous plume in each new The RovatC.ften-.mch Ohscn-atft ■•mn n phiUcgraph Inkrii ,i: FlClKK 129. Comet 1908. III. September 29th, 190S, 50 minutes" exposure. The photograph shows a strangely abnormal appearance in the tail, anil apparent distortion, perhaps due to electricity in space. The meteoric swarm is probably difl'iised aronnd a soniewh.it dense centre. M\i;(ii. 191. KNOW i.i:nc, |- 12.i position the nucleus occupies? No dynamical suggestion, save that of some radiative or electrical phenomenon, seems to satisfy the conditions. The pressure of light has been tried, and does not appear anything like great enough to explain the phenomena. For over thirty years I have examined suggestion after suggestion with no dvnamical satisfaction, and nothing but an induced electrical [)henomenon seems left as a probable cause. Many facts point to the Sun being an electrified body. The frictional disturb- ance produced by its tidal action on the cometic particles must produce electrical separation. The like kind is attracted, the other repelled. Thc^ phenomenon of ensphering envelopes suggests that the attracted kind escapes, and leaves the comet charged with the unlike kind, .\ided by the Sun it produces an induction that acts upon the matter of space, and temporarilv separates the two, electric stress producing luminosity. The greater the nucleus the greater the self-repulsion produced, and the slower the impulse travels, and consequently the greater the resultant curve. \\'ith subordinate nuclei the self-repulsion is not strong, and the impulse travels faster and the subordinate tail is straighten. If the head is made up of many orbitally connected nuclei the tail is multiple, the several parts mutually repelling one another. (See Figure 1.50). Distortion of Tails. Why are the tails of comets sometimes subject to such apparently violent action ? Possibly because some passing meteoric swarm has already set up electrical conditions in space. The Chemistry of the Spectra. \\'h\- does the carbonic oxide show throughout the mass of a comet ? Possibh' because carbonic iixide KlGLKK 1.50. Comet 1908. III. October 3rd. 1908, 30 minutes exposure. Multiple tails, possibly due to several nuclei. •iGfUi; 131. Comet 1901. I. May 4th. 1901, 15 minutes' exposure. Tail produced by an apparently dense meteoric swarm. ina\- be spread through space. Why is cyanogen seen in the head ? Possibly because this compound of carbon is formed at excessive temperatures, as it is known to be a constant constituent of the gases of tlie blast furnace. Of course, it would burn were there free oxygen, but the existence of carbonic oxide in space suggests that there is none. The whole problem of comets, bristles with dynamical and chemical difificulties : but do not let us use theoretical suggestions obviously inapplicable. Electricity is a subject we are only just beginning to understand. We are onh- on the threshold of the prodigalit\- of its varied phenomena. The wonderful ( hemical and luminous phenomena, now being re\ealed b\- Strutt, as associated with the varied molecular " states of nitrogen under electrical influences: the extraordinary complexities of brush discharges in different gases so long known, but now so much increased by Kaffety's experiments: the varied glow of vacuum" discharges in all the richness of their complex phenomena ; these are a few of the experimental effects of electricity : whilst terrestrial magnetism, the corona, the aurora and the varied complexitN- of the tails of comets are probably each a cosmic phenomenon connected with this same most protean and potent agent. The Oric-.in of the Comets. The study of partial impact and the theory of the third bodv in all their multifarious conditions and KN()\vi,i.i)r,i:. Makcii. 191-'. variety as rc'},Mrds (itnsity. mass, depth i)f ciicoiiiitir, anil all tlie other circumstances we have studied in these articles, continually present us with rotarv masses of dense teases, from wiiich selective molecular escape has removcil the li},'ht f,'ases. Such rotarv lU'lnilae tend always to hecome at a certain sta^e meteoric swarms. A coujile of minor planets f^razinj,' would ine\itahl\ |)roduce a meteoric swarm. The ends of the spindle of the third hody of collidinj,' suns we have deduced would be larf^ely iron, and would tend to segregate into a number of such associated groups of particles, gradually cooling to larger and larger masses. It is a curious coincidence how man\- of the more massive meteoric blocks are iron. The immense majoritv of impacts must !"■ obliipie, aiul all grazing impacts must set up rfttation. and the heavier elements left by atrimic sorting must pass through the meteoric swarm stage. Hence there is no cause to wonder at the number of comets, nor that space should be rich enough in jiartides to be lit up when electrical disturbances tend to rend«-r cosmic dust luminous. The whole subject of comets, their chiiracter and origin, their gorgeous magnih- cence, the beauty of their ignited meteoric trains, is full of wonder and interest : and this is my excuse for submitting these dynamical deductions as offering suggestions that may be used as tentative e.\])lanations of their origin and character. RHX'IEWS. MICKOSCOPV. Moih-nt Microscopy. — By M.I. Cross and Martin J.Colk. J25 p;if;es. 113 illustrations. 83-in. X5i-in. (B.aillicre. Tindall & Cox. Price, 6/- net.) The fourth edition of this excellent treatise has now been reached and forms a handbook of considerable value to the amateur microscopist. It would not be difficult to criticise such a work because of its omissions, but such criticism would be obviously unfair. The ground that it attempts to cover is so large, ranging as it does from the use and manipulation of the microscope to the mounting and preparing of objects of widely varying descriptions, that omissions are inevitable; but enough is said in each case to enable a beginner to appreciate the principles involved. Reference can then be made to larger and more specialized works with a feeling of confidence that the knowledge already acquired may be regarded as sound, and that it will serve as a good foundation. The first four chapters, forming Part I of the book, are devoted to the microscope and accessories, and sufficiently practical instructions are given to enable a student to start work on proper lines. It is interesting to see that the concluson is reached that an English microscope is .still to be preferred to a Continental one, when really serious and critical work is intended, a con- clusion that is in agreement with the opinion of the majority of serious workers in this country. Part II, consisting of Chapters VI to XX, is devoted to methods of preparing, stain- ing, hardening and mounting microscopic objects of all descriptions, and embodies practically all the well-known processes in each branch. Simplicity is the key-note all through, and it is dilficult to imagine in what way the subject could be better dealt with, at least considering the limitations imposed. The instructions given are essentially of a practical nature, and the expressed intention is to avoid the use of needlessly expensive appliances. Part III consists of a series of articles by well-known workers in the particular branch in which each one specializes. The subjects are dealt with, as might be expected, in a masterly manner, but the Chapter XXI. by Mr. Cheshire, on the Petrological Microscope, is particularly interesting. The polariscope is to the amateur a most fascinating adjunct to a microscope, because of the beautiful effects that are to be observed with comparative ease, but it is almost astonishing to notice that in a great number of cases the user has no idea of the elementary principles involved. Mr. Cheshire has written a simple and lucid explanation of the subject that cannot fail to be of exceptional service, and that has the particular merit of giving a concrete notion of what really takes place when light is polarized. In general, the book is so evidently the work of earnest workers, that it may with con- fidence be commended as a safe guide for those entering on any field of work that involves the use of the microscope. J. i:. B. PSYCHOLOGY. Iiifrixltiction to Psycliolo->--«»»».o«'- i>iijr Figure 138. A Siin-dial at Swardeston. consecration crosses (Figure 142) are now in the out aide wall ! Til is is also the easy explanation of sun - dials being found inside churches. Secondly, we must remember that the " Reformers " and their immediate successors have left their trace every- where ; scarcely anything which is sacred or even that which is simph- ecclesio- logicall)' interesting appears to have escaped them. One finds consecration crosses ni u t ilated, " embellished," ami duplicated; sun-dials duplicated (more or less faultilv) and originals either mutilated or " improved " b\' added radii, and so on ; i Figure 139. A Sun-dial at Great Easton. wt^- — «niws^-*" -H ' \ ^,--A^. Figi:ri-: 140. \ Sun-dial at Tacolneston. in fact, where the examples are well weathered it is often extremely difficult to dis- tinguish the true from the false. The suggestion that Saxon dials are consecration crosses found many supporters, but that they were mistaken is easilv shewn. The consecra- tion of a Catholic church is a most interesting ceremony occup\-ing several hours, and as all the churches directly or indirectlv re- ferred to are pre- Reforma- tion, a brief reference to the crosses (Figures 142-144 and 147 and 148) will be inter- esting, and will explain what proved a difficulty to so l6)^»Vi< -ill .<4Kii— fr^'^ifc 6PFG0Rjy/-M(N ,rT5rLf)0NNEHI r ^[:^^ H^^PARM^EPR^HTRgRHND] CAnoToFml an-IK HlTlElPlAIAfNNCPANfRon GRV_N5EXPf>lfJ6Rf6oi^ ^ — Figure Hi. A Sun-dial at Kiikdale. Ai'KH.. 19i:. KNOWLEDGE. 129 manv persons. There- are twelve crosses upon the inside n-alls (not on tlic pillars or columns) — one each side of the main entrance, one each side of the sanctuary, and four upon each side wall. Thev are seven- feet si.x-inches from the floor and are some- times painted upon the \\alls. sometimes of metal let into the walls, and sometimes cut into tiie stone (or, if the walls be not of stone, cut into inserted stones). .\ metal, or wood, sconce (in which a candle is kept burning Fir,i-[,;i It:. It All Saiiitj.'. Norwich nil — as sometimes is also a cross on both door- jambs of the main entrance. These two iwhich are four-feet six-inches from the .ground and have no sconce) are usually, but not always, cut into the jambs ; if the jambs are made of brick two small stones (in which the crosses are cut) are let into the bricks. The large number of crosses sometimes found upon door-jambs puzzled manv correspondents (one of whom suggested that thev are " Institu- t ion "" crosses, i .c. 1 K.URE 143. Consecration Cross at Rockland. St. Marv Figure 144. Consecration Cross at Sicevton. from the beginning of the consecration cere- mony until the church is closed at night, also all day on the anniver- saries of the consecra- tion) is fi.xed above or below each cross. An interesting exception to this is seen at All Saints', Norwich, where the sconces were in the centre of the crosses' (Figure 142) as shewn by the remains of the tangs still visible. In the course of the cere- mony these twelve crosses are anointed b\- the Bishop with his thumb dipped in hol\- FlGl'RE 145. Mason's "mark'' at Claxton. whenever a new- appoint- ment was made a cross was cut, in commemora- tion, upon the jambs), but this duplication has been explained when speaking of the " Re- formers " as also is the eccentric form some of tiie original crosses now take. Those persons who believed the Saxon dials to be "Masons' Marks" were equally mistaken. "Masons' marks" are so \aried and numerous as to be countless; and it is customary for a mason to mark, or " sign," his work, just as an artist uo KNOW I.I DCIL AiKii.. i'»i: siKiis his piitiirr. The positinii of the mason's ■• mark" has varied from time to time. Apiiarently. at the hefjinnin^,' of the sixteenth century it was customary for a mason to place his "mark" Kirkdale dials (Figures 1.56, 139 and 141). The former although circular has only the lower radii cut, both the latter are semi-circles. It has some- times been said that certain dials cannot be Saxon because they were obviously made at a later period ; but the term " Saxon " refers to the notation, not necessaril)' to the work- manship. The varying spacing of the lines on Saxon dials has been the cause of much perplexity to those who iiave failed to notice a much greater variation in modern sun-dials, usually owing to the orientation of the build- ing (or — more correctly — the declination of the dial). ("hurches are invariablv built approxi- m a t e 1 y "East and West," but secular buildings cannot alwa\s be placed according to that rule : therefore the modern sun-dials which are found upon private houses, schools, and so on, vary to a much greater extent than do the Saxon dials found u[)on churches. Although a ver\- large number of Saxon dials still have the tang of the gnomon embedded in the stone, most careful search has failed to discover one with the original gnomon intact — which is not surprising when their age and exposed posi- tion is remembered. 15ecause the tang is horizontal many persons believe the only possible gnomon was a hori- zontal one, and that therefore the dials cannot possibly be sun- dials : but this error is probably the outcome of having heard, or read, the erroneous statement, " The gnomon must be parallel to the Earth's axis." (The angle or otherwise of the gnomon makes no difference to the possibility of reading time.) Perhaps the 4 FiGlKF, 150. Mason's "mark" at Hellington KNOWI.I.DC.i:. Ai'Rii.. l'M2. t)cst possible cvidL-ncc tliat tlic Saxoii dials itrc sun-iiials is afforded In the (".ruat lulstonc, Swardcston. Kirkdalc (i'if,'urcs 1J(). K58, 141), and Markft Decpirif; dials. In the majority of instances one finds simply a tliiil. i.e.. the dial without inscription or ti;L;iires ; hut the two former liax'e an inscription (indisputahly contemporaneous with the dials), and both of the latter have fifitirea denotinj; the hours. In the centre jianel of the Kirkdale dial the inscription (translated) tells us, "This is Day's Sunmarker at every Tide," and that (translated) on the (ireat Hdstone dial (a sketch The term " Orientation " previously referred to is frecpieiitly misunderstood. It is very usual to say " Churches are built Kast and West " but comparatively few persons know that very few are due iiast, and that there is generally quite sufficient variation to make the adjustment of the markings of a sun-dial necessary. The variation is caused in this way : — The foundations of a church are laid according to the position of the sun on the patronal feast ; therefore a church dedicated to, say, St. John the Bajjtist (June 24th) is not in exactly the same position with regard to East and West as one FiGruK 151. The " mark " of a mason liviiiy Norwich. of which was verv kindh' sent h\ the Rector) describes it as the " Clock of Travellers." In instances — of which there are many — where the radii cannot be assigned to an\' known notation of time, ecclesiastical (c'.j^.. the canonical hours) or secular, the explan- ation will probably be that they are due to the " Reformers." The finding of Saxon dials wliicli haw no hole (and obviously never had one) for fixing a gnomon has been claimed as convincing proof that they are not SH/i-dials; but Mr. Arthur Bentley's "conjectural method of fixing the gnomon " (Figure 146), which is reproduced b\- his kind permission, has most effectualK' explained tliat difficulty. It is interesting to notice how easily Figures 142-145 may be mistaken for Figure 140, as all three examples are very much weathered, and a casual observer would probably notice l^ractically no difference. Figure 140 is one of the Tacolneston dials. Figure 142 is a conse- cration cross (.All Saints', Norwich), and Figure 145 is a mason's mark (Claxton). Figure 152. Another "mark" of a mason living in Norwich. dedicated to, say, St. .\ndrew (November 30th) — and this divergence has to be allowed for when marking the lines upon the sun-dial. Sexton's Wheels (which have been unaccountably confused with Saxon dials) are portable articles, and only two specimens are known to exist — -at Long Stratton and Yaxley, both in the diocese of Norwich. The}' have no connection either in form or use with sun-dials and a very interesting illustrated description of them will be found in "Norfolk .Archeology," Vol. IX, 1881. The authors are greatly indebted to the large number of persons who have not onlv corresponded but have gone to considerable trouble in making rubbings, sketches, and so on ; especially to .Mr. R. H. Flood (who lent a \cry large number of interesting rubbings), and to Mr. .Arthur F. C. Bentley (who most kindly made and presented practical models of four primitive sun-dials — set out for the latitude of Horstead, in Norfolk — and whose " conjectural method of fixing the gnomon " helped them out of what undoubtedly proved one of their greatest difficulties). THE FACE Oh' THE SK\' 1-OR AEW Bv .\. r. 1). cr().\lmi:lin, b.a., d.Sc, f.k.a.s. D-iic. >.u,. .\K...... M,:.o,ry. Vc ,us. M.nrs. J upiler. Uraiiu-s. Nep une. R..\. Dec. R.A. Dec K.A. Dec. R..\ Dec. R.A. Dec. R.A. Dec. R.A. Dec. R.A. Dec. Greenwich Noon. h. m. 0 h. m. „ h. ni. " h. m. ^ h. m. . h. m. h. nl. h. m. ^ May 5 .. 2 48-6 N.162 iS 75 S.28-4 . .9-8 N. 5-5 I 46-3 N. 95 7 "S'S N.24-0 16 49-6 S.21-6 20 2^-6 S.19-9 7 3- -8 N.2r2 3 7"9 ■76 22 197 .S.I4-7 2 9-6 II-7 7 25-9 23-0 10 47-4 21-6 20 2,-6 20-0 7 32-2 21-2 .. 15 •• 3 =7-5 i8-8 ■ 5o'7 7 '9 2 33'2 1.3-8 7 38-3 23-1 16 45-. 21-5 20 23-6 20-0 7 326 21-2 II 20 . . 5 47 4 20 0 7 19-6 N,27-4 2 13-1 lOI 2 57 -2 ■.i'7 7 50-7 js-S [642-5 21-4 ao 23-4 20-0 7 33' 21 2 ,. 35 ■• 4 7'5 =o-|} I. 5T« N. 2-5 2 39'7 '2-7 3 2' '7 17 '5 8 31 22-0 16 39-9 21-4 20 23-2 20-0 7 .13-7 21 2 4 =7-8 N.2I-8 16 .6 S.24-2 3 .0-8 N..5-7 1 46-6 N.,9-= 8 .5-1 N.2,-3 16 37-2 S.21-3 20 22-8 S.20 0 7 34'3 N.21-2 Table 12. Sun. Moon. i\la IS Jupiter. 1- \>. L P 1' 1; L T y '1 P B L, L^ Tj •12 Greenwich Noon. Q 0 ^ ^ Q h m „ ^^ ^ ^ 0 0 h m h m May 5 -2;, 4 -30 309-1 — 1-2 -166 +7« 300-3 4 5"2<; 96-2 •39 +6-6 -29 323-3 1498 10 50 3-3 58-6 7 58-9"' 101 -6 ■28 -r7-9 -2-9 314-6 3160 ■ 14 e 3 27 '" Table 13. III. c denote tiioriiing, evenin.5 respectively. Greenwich Civil Time (day commencing at midnight) is used. P is the position angle of the body's North Pole measured eastward from the North Point of the disc. B, L are the HeUo-(planeto-lgrapliical latitude and longitude of the centre of the disc IN. latitudes +). In the case of Jupiter there are two systems of longitude, the first for the equatorial region, the second for the temperate zones. T denotes the time of passage of the zero meridian. Intermediate passages for Mars, Jupiter I and II may be found by applying multiples of 24" 39- 7"", 9" 50-4", 9" 55-6"" respectively. O. q for Mars are the position angle and amount of the greatest defect of illumination. The Sl'n continues his northward march, but with slackening speed. During Mav the semi-diameter changes from 15' 53"-6 to 15' 47"-8; Sunrise 4" 34°" on 1st, 3^ 52"" on 31st. Sunset 7" 20" on 1st, 8" 3"" on 31st. As this is probably the year of minimum, sunspots and prominences are few and small. Mercury Is a morning star throughout the month; being south of the Sun it is better placed for observers in the southern hemisphere. It is in elongation 26° from Sun, May 13th. The semi-diameter diminishes from 5" to 3", the illuminated portion of disc increases from 1 to }. Venus is approaching superior conjunction, and is too near the Sun for convenient observation. Semi-diameter 5", tVs of disc illuminated. The Moon is full Mav r' 10" 19" m, L. Quar. 9'^ 9" 56™ ;;;, New K)"" lO" 14'" c. F. (Juar. 23" 2" 11" e, Full 30'' 11" 30" e. Apogee 7" s" e (semi-diam. 14' 48"); Perigee 19" 5" e (semi-diam. 16' 24"); Maximum Librations 5° W. April 30", 7° N. May 6", 6° E. 14", 6° S. 20", 5° W. 26", 6° N. June 3rd. The letters indicate the region of the Moon's limb that is brought into view by libration ; E. W. mean the East and West with regard to our sky, not as they would appear to an observer on the Moon. Thus W. is the side towards Mare Crisium. Disappearance. Reappearance. | Date. Star's Name. i .Magnitudes. Mean Time. Angle from N. to E. Mean Time. Angle from N. 10 E. 1912. .M;iy 2 ,.' 3 „ 8 ,, 20 ., 27 ,. 29 ., 29 „ 30 „ 30 BAG 5253 B.-\G 5286 BAG 7077 C Geminorum BD— 13° 3802 BD— 22° 3989 42 Librae Anlares B-^C S5"3 5 '4 5 '4 6-2 5'.T 6-8 6 0 5-0 6-2 h m 9 39" 0. 0 m 2. 9 /« 7-37 •: 11.15.- 9.56 « li.SS^ 8.48 c- 9-54 '■ 165' 116 59 124 136 61 159 114 99 h in 10. 25 e 1.20 /« 3.28 m S.33" 10.42 " 15 42 .. 16 412 May .7 4 0 . 2 .. .8 43; 0 ,. .9 4.12 U I ,, 20 * Q 2 ■ • .. 21 14 I) ,12 .. 22 2 0 '43 •• 23 12 0 i4 .. 24 0 24 •• 25 3' 0 4 ,. 26 52 u >4 .. 27 3 0 24 I* ,. 28 I (^ 24 ^^ „ 29 2 0 3 ! ,. 30 4,' C) 3 .. 31 4 0 2 Satellite phenomena visible at Greenwich, 1* ll'' 45""^ II. Oc. R.: 2^ 10" 43'"t' III. Sh. E., ll" 27"'c III. Tr. I.: 3" 1" IQ^m III. Tr. K.. 2" 3\"'n, I. Sh. I., 3" 12'";h I. Tr. I. : 3" 11" 53" 45V I. Kc. D. : 4" 2" 43"'»; I. Oc. R. ; 4" ll" 13"'e I. Sh. E., 11" 50"\- I. Tr. E. : 7" 4" 7""m II. Sh. I.: 8" 10" 20™ 29»e II. E.c. D. ; y" 2" 3'"/« II. Oc. R. ; lO" O" i6"',n III. Sh. I., 2" 41"'»H. III. Sh. E. 2" 49"'m III. Tr. I.: 11" 1" 47"' 24" I. Ec. D.; 11'' lO" 53"" e I. Sh. I., ll" 22'" e I.Tr.I.: 12''l''7™mI.Sh.E.. l"35""»Hl.Tr.E.; 12'' lO" 54"'c' I. Oc. R. ; 16''0''55"' Sl'm, II. Ec. D. ; 17" lO^SQ^e II. Sh. E., II" IQ-^c II. Tr. E. ; 18" i" 41™ 8"/)/ I. Ec. D. ; 19" O" 47™/;/ I. Sh. 1. 1" -'"ill I. Tr. I., 3" 1"'//;. I. Sh. E.. 3" 19'"/// I. Tr. E. ; 19" 10" 9'" 33V I. Ec. D. : 20" O" 38"/// I. Oc. R. : 20" 9" 29""^ I. Sh. E.. 9" 46"V I. Tr. E.. 9" 52"'f I II. Oc. R ; 23" 3" 31'° 30"/// II. Ec. D. : 24" lO" ii'^e II. Sh. I.. lO" 56""^ II. Tr. I.; 25" 1" 13"°/7» II. Sh. E., 1"33'"/)/ II. Tr. E. ; 26" 2" 41'"/// I. Sh I.. 2" 51""/;/, I. Tr. I.; 27"0"3'" 24"//; I. Ec. D.. 2" 22'"/// I. Oc. R. ; 27" 9" urc 1. Sh. I.. ')'']7"'c I. Tr. I.. 10" 48'" 39V III. Ec. I).. 11" 23"V LSh-K-.n" ,Urf I.Tr.i:.: 2k" 1" lO™/// III.Oc.R.; 28" 8" 48'"i.' I. Oc. R. .Satim, but the angle tan ''■% is formed. This is not an encouraging start, but on applying this to smaller angles good approximations well within the draughts- man's error are reached I see Figure 154). Let A B C be the given angle. Describe the circle A C with centre B. Produce C B to the circumference at D. Bisect A B at E. Join D E and produce to the circum- ference at F. The arc A C is approximately trisected at F. The word in italics is unfortunate but necessary. If we try an angle of 120° it is actually bisected, whereas one of 90", as we have found, comes within 7' of the proper place. Calculation shows that at 60' the error has fallen to 1° 47' ; for 45° it is 43' only, then it rapidly decreases and at 30° it is less than 1 1', which is already negligible ; the two- thirds angle always being slightly too small. Mr. Bingley's method. I find, gives precisely the same results, his E J, E K, lines corresponding to my D F though obtained by a more elaborate construction. He, however, bisects his angle first, so that when I speak of an angle 30° his would be 60°. To pro\e the relationship of the two methods let us take a Figure 153. FiGURi; 154. part of his figure, but with a larger angle and a complete circle (see Figure 155 where A D. E C, and G D are bisected). Take the centre of rectangular co-ordinates at A. the axis of X, A C, and the co-ordinates of D (a, b) where a" + b' =1. The co-ordinates of the points will be : — A, (0,0); C, (1,0); D, (a,b); 5a + 2 5bN " 8 rs) Equation to E I b^5b" 2 8 5a + 2 a 5a + 2 8y — 5b _ 8x — 5a — 2 -b ' - a - 2 b ••■y=^^^»x + i). This and the equation to the circle x' + y" = 1 , are obviously both satisfied by y = 0, x = — 1. Therefore, K E when produced cuts the circle at Z, and the two constructions produce the same results. In the above investigation the co-ordinates a, b, do not necessarily refer to the circle ; the a^ + b" = 1, is not used ; showing that the point D may be any- where and K E always cuts the circle at Z ! (see Figure 156). Of course the approximation is not FlGL'RE 155. FlGURK 156. obtained unless D is taken on the cuxumference. There is no particular mystery about the process finding the circle at last, for C is of necessity on the circle. The construction of Figure 156 doubles a straight line. C -A. by a system of bisections — a rather curious result. H. F. CHESHIRE, B.Sc. F.I.C. Hastings. THE TRISECTIOX OF ANGLES. To the Editors of '' Knowledge." Sirs. — I am much obliged for the interest that your correspondents, Messrs. Thomson and '' Computer," have taken in this matter, originated by my little article in your November. 1911, issue, and for their corrections and remarks thereon. I only intended the method to apply to small angles of 45° or less, as then stated, as it is not applicable to larger angles. With the means at my disposal, which are. unfor- tunately, very primitive, I could not detect any error, but I quite accept the corrections, of course, and a"m only sorry that the method turns out to be inaccurate, or, in other words, not a method at all. As to angles of exactly 45°, 90°, 135° and ISO', surely these are mathematically divisible by a much simpler method than Mr. Thomson's No. 2, viz.: the angles 45°. 90° and 180° by that of 60°, and the angle of 135° by that of 90° ? I have always so treated thein. and should be glad to be shewn any correction that they require. ,„. , „ .. CHAS. S. BINGLEY. 18d, Albion Road. N. THE FLIGHT OF BIRDS. To the Editors of " Knowledge." Sirs, — The methods of birdsin maintaining or rather recover- ing energy of position during flapless or soaring flight is very easy of observation in the plains of India during the beginning of the hot weather, and the following notes may be of interest to some of your readers less favourably placed as regards opportunities for watching them. The two conditions required, namely, ascending currents of air and a plentiful supply of large soaring birds, are both present. At the beginning of the hot weather, before the more regular winds set in, the air near 135 136 KNOW 1.1 : DC ".!•:. AiMdi. 1912. the surface of (lie Kroiind is intensely heated clurinK the middle hours of the day, the atmosphere as a whole beinK more or less at rest. This unstable state of a healed lower layer (jives rise to niunerous minute whirlwinds, locally known as " Dust Devils." varying in size from a few feet to perhaps a himdred y.irds in diameter, and In duration from about ten seconds to as many minutes or longer. Their .ippcar.uice on first forminp is that of a wliirlitiK colmun of dust, mixed with leaves, straws, and so on. which, after continuing for some time. K'adually lose their sharp outline and appear to be more or less dissipated, but the consequent uprush of air can be traced for long afterwards by the cloud of dead leaves hovering far above the surface of the earth. The action is, of course, similar to the formation of waterspouts at sea. Soaring birds, such as Vultures, Kites and Storks, are common ; indeed, if is of very rare occurrence that the sky can be searched for two mimites without discovering at least one Vulture. These, however, are usually at such an elevation that they are useless for the present observations. .•\ low-flying bird is required, and one is chosen flying across country, perhaps two or three hundred feet above the ground and straight as the proverbial crow. Observed with good glasses, the wings and tail are seen to be practically motionless as a whole, but with a constant adjustment of the plane angles. The loss of elevation as it proceeds is clearly noticeable, and if it cannot find an external source of energy it must flap or come to the ground. It need not proceed far, however, before encountering a dust devil uprush, on meeting which the straight flight is changed to a circular one, on which it mounts, still without flapping, to a limit either at which the uprush of air is no longer strong enough, if the dust devil be small, or at which the Vulture chooses to start off again on its straight flight. It should be understood that the birds do not circle on a dust devil in active operation, as the motion is then extremely violent, but after breaking, as noted above, the vertical current becomes suitable for the birds' purpose. Numerous dead leaves may occasionally be noticed hovering amongst the circling birds. At times the dust devil movement does not begin by the intense motion as previously stated, but a gentle uprush vortex motion sets in. which gradually drifts across the country. These are frequently occupied by twenty or thirty Vultures, which continue to circle as long as visible. 1 he upward current is detected by the radially inward draught felt when the movement passes near the observer. In the early morning or late afternoon, when the dust devils do not occur, the Vultures invariably proceed by alternate flapping and soaring flight. The extent of the bearing power of these upward movements of the air is evident from the phenomena of dead leaves drop- ping out of the still evening sky, as late as can be observed up to and after sunset, the last dust devil having broken up some two or three hours previously. Melbourne. ' S. TrLLOCII. THI£ SUN'S PATH IN SPACE. To the Editors o/ "Knowledge." Sirs, — The direction of the Sun's path in Space has been calculated with some degree of certainty by observations ot " Star Drift." Could not its path be ascertained with a greater amount of accuracy by calculations of the diflering positions of the centre of gravity of the Solar System, which must change to some very slight but still appreciable degree, with the relative changes in the positions of the planets ? If, for instance, when the larger planets are in conjunction, or in opposition, or at their perihelion, or at their aphelion, a sufficient number of calculations were made of the consequent varying positions of the centre of gravity of the Solar System in Space, some definite resultant might be found, shewing the direction in which it is travelling. G. R. GIBBS. BOURNK.MOUTH. ASTRONOMY. To the lidititra of " Knowli'.dgi;." Sirs, — I believe I am right in saying that while some account for the origin of the moon by .saying that it at one time formed part of the earth, — an offshoot from the earth, and so on, — others explain it as being an old planet. The reasoning for this latter explanation seems to be that a body goes through the following processes: First, the sun; second, the sun cooled and become a planet, fit for the abode of living creatures ; third, the planet cooled and become a moon, a dead world. To take as an example the sun and the earth. The supposition would be that the earth was previously a sun, but had now cooled and become a planet. As the sun gets cooler, so, naturally, will the earth, until the latter eventually reaches the phase of a moon. It seems to be rather on these lines that Mr. Proctor bases his theory of Jupiter's moons being inhabited ividc " Expanse of Heaven"), Jupiter being put forward as a sort of sun, with his moons really planets (Jupiter in this way might be regarded as illustrating the half-way stage in the evolution of a sun to a planet fit for living creatures). At a lecture I attended not long ago the lecturer happened to mention the theory of the moon being an offshoot from the earth, and at the close of the lecture I mentioned the other theory (just described).. ind asked him which of the two was the more universally accepted. He seemed never to have heard of the second theory at all. Can you tell me which of these two theories finds most support from astronomers of to-day ? "INQUIRER." Catford, S.E. ON THE ROTATION OF VEXL'S. To the Editors of " Knowledge." Sirs, — I write this letter in answer to the doubts expressed by your correspondent. Mr. Harrison, in the hope that my reply may be of general interest to your readers. Mr. Harrison first contrasts the conclusions of Belopolsky and Slipher as to their spectroscopic evidence. It is to me amply evident that in this matter Slipher's con- clusions are the stronger, founded as they are on photographs taken on a more favourable opportimity and with a more powerful spectroscope than that used by Belopolsky. It is a striking fact that Slipher's results indicate no rotation at all — for the final mean radial velocities deduced are conflicting in sign, and either pr.actic.illy equal to or less than the probable errors of observation. Tlie evidence is therefore negative. Referring to the Lowell Observatory Bulletins Nos. 3 and 4. I find the following statements: — " \ rotation period of twenty-four hours svould in the case of Venus imply an inclination of 15' to the normal in the planetary lines. The probable errors of determination of the inclination of the lines are. in the case of Venus, somewhat less than 1' in the final result." " When Mars' spectrum w;is measured to test the method — an inclination ov b''b was found — indicating a period of revolution within an hour of the known one." (These quotations are not verbatim but condensed.) It is then apparent that had \'enus any such period the latter could be determined with more than double the accuracy possible in the case of Mars. It is thus clear that Venus' period is much longer than tliat of the Earth. Now for positive evidence as to how umch longer the period may be, visual observations are our only resource ; and thanks to the purifying influence of modern research, that source is now reliable. I have myself been able to corroborate the markings seen by Schiap.arelli, Lowell and others, and I am convinced not only of their reality on the planet, but of their fixity with regard to the terminator. They indicate without question that the planet turns always the same face to the Sun. The observations of Schroeter and De Vico, quoted by Mr. Harrison, were interpreted by them to indicate a period about Apkii.. 191; KNOWLEDGE. 137 equal to that of the Earth. It is absurd to suppose that they could also support such a period and also a period half as long again. To do this all the planetary markings would have to be in two places at once — in his eye and his telescope perhaps they appeared to be — but on the planet never. If the markings charted by the older observers were real they should be easily visible in the vastly better telescopes of the present day. In ordinary air— the better the telescope the more immaculate the planet appears. It is only under very favourable climatic conditions that the observer can be assured of their reality. They are harder to see than the canals of Mars. It is therefore foolish to quote the early observers, whose evidence in the light of modern research is thus proved to be valueless, for they never saw canals on Mars. Nevertheless to them is owing the credit of opening the question. The radial markings discovered by Lowell are just those to be expected on a planet which is like a cryophorus : a planet which has one side permanently heated — and conseciuently having an inward and upward fountain circulation of atmosphere. .Again. G. H. Darwin's "Tidal Theory" suggests the reason for and the probability of Venus always turning the same face to the Sun — which probability is increased by the likelihood that Venus never revolved as fast as the earth did at the time of the birth of the Moon. For Venus has no large satellite. Hence she was never disrupted by the tidal action of the Sun operating in conjunction with centrifugal force, due to very rapid rotation. Vet, since solar tides on Venus are much more potent than on the earth, this disruption is a priori the more likely. If. then, Venus never rotated as fast as the Earth once did, she would the more quickly have been stopped by these same tides ; and having no large satellite, there is no other attractive force to oppose that of the Sun. To sum up, every piece of reliable evidence we have been able to adduce points to a rotation period oi two hundred and twenty-five days. There is not a shred of conflicting testimony. There seems to me to be no reason whatever for hesitating further to accept the indicated conclusion that the orbital and rotational periods of Venus are identical. JAMES H. WORTHINGTON. LOWF.I.L Observ.atorv. Fl.\gst..\i-i-. A.T. ORNITHOLOGY. To the Editors of " Knowledge." Sirs, — In " Knowledge " for December, I noticed that a correspondent wrote regarding the starling as a mimic ; I write an article headed — "' Does the starling relieve sheep of ticks ? " On grounds where sheep are grazing, especially if such grounds be somewhat boggy, starlings are seen perched upon the backs of sheep. Starlings are said to visit sheep in order to feed on the ticks which infest the sheep. After close, patient watching I could never see the starlings pick into the wool on the back of the sheep for ticks. I am inclined to think that the starlings visit sheep because they find their backs comfortable and handy. Then these birds seem to be of a very friendly nature to animals they are accustomed to feed amongst. .\n article in " Nature Notes " of the Scots- man recentlv showed the social nature of this bird in captivity with a cat, " Starling and kitten." The bird was seen perched upon the back of the cat. Sometimes the starling was found sleeping in this position for half-an-hour. EDGAR GRANT. EDLS'BURGH. THE VELOCITY () E LKIHT. To the Editors of " Knowledge." Sirs, — I am a little disappointed to find that Colonel Gibbs was not facetious in his suggestion as to the velocity of light. May I point out that his error is based on his fundamental fallacy that the eye " is not capable of seeing anything that passes across its field of vision in less than a tenth of a second." This may or may not be true of some objects — such as a bullet — -but it is absurd to suppose it true of a luminous object. CHARLES E. HENHAM. Colchester. THUNDERSTORMS. To the Editors of " Knowledge." Sirs, — Mr. Chamberlayne asks in your issue of Jaimary last : — " Inasmuch as the world is round and thunderstorms like everything else have a beginning, it follows that the first flash of lightning in any storm must be directly over some- body's head. How is it then that we cannot meet with anyone who remembers anything of the sort ? " My estimate based on observations here would be that out of one hundred thunderstorms one breaks almost exactly overhead. .A remarkable case occurred here about six weeks ago ; remarkable because the discharge came to the ground, which is unusual at the very beginning of a storm ; and it was so heavy that it injured telephones. Tr.\nsv.a.\l Observatory, K. 1'. A. INNES. Johannesburg. To the Editors of " Knowledge." Sirs, — Mr. Chamberlayne's letter on " Thunderstorms " recalls an instance which I may offer as an answer to his question. One afternoon in the late spring of 1892, at Denver, Colorado, the sky clouded slowly, whilst the temperature remained rather high. .At six o'clock the heavens were entirely covered, and half an hour later, without any preliminary electrical display, a brilUant flash of Hghtning rent the clouds, and was followed instantly by a heavy peal of thunder. In a few minutes rain began to fall. The storm, with its attendant electricity, lasted nearly an hour before moving away. This is the only instance of the kind that I have particularly remarked. Here, on the coast of California, thuiulerstorms, even of a mild type, are infrecjuent, so there is little opportunity to make observations of their phenomena. Storms in the mountains are sometimes visible here, at a distance of from fifteen to twenty-five miles, and, as these are always local in character, the " first flash direcily overhead " must often have been observed in them. CHARLES C. CONROY. Los .Angeles, Califoknia. NOTICES. THE HORNIMAN MUSEUM. -The new Library at the Horniman Museum, which was recently opened to the public, will now be available on week days throughout the year, from U,0 a.in.to 9.0 p.m., and on, Sundays from 3.0 to 9.0 p.m. It will, however, be closed on Christmas Day, Good Friday and Bank Holidavs. FLAME CARBONS.— Messrs. William Gniper and Company, have introduced improvements in their flame carbons, with the result that their business in this depart- ment, as in others, shows considerable increase upon that of 1910, or indeed of any year since they took over the business of Messrs. Paterson and Company. Ill': K\()\\iJ-i)(;i{ ()!• Till- ij\"i\r; \.\i'()li:o\ DiKlXC. TIM': LAST I'llASi: (iM^-icSiiJ. liy A. M. HKUADLLV, Author 1}/ " Wtpolcoii in Caricature." SlNci-: the bef,'iniiiii}i of the present \ear two Ixioks have been publislied which oiij^ht to throw some new lifjht on tlie iiersonality of Napoleon during the last five years of his eventful life. If the student is somew hat disappointed at the paucit\- of information of this particular kind contained in the superblv- printtd paj^es of Monsieur Frederic Massoii's monumental work " Xajioleon a St. Ui'lrin'."' he will find some consola- tion in the livelv pages of Mr. G. L. de' St. M. Watson's ".-V Polish Exile with Napoleon'" — a work based mainly on pains- taking research in his- torical ground w hich max fairly he described as unbroken. In the concluding; volume of his great bio- graphy of the younger Pitt, entitled " Pitt and Napoleon Miscellanies." will be found a very interesting account of an interview with Napoleon which took place at Elba on the evening of Janu- ary 26th, 1815. Four days previouslv two English travellers, Major I. H. \'ivianand his com- panion, Mr. W'ildman. had arrived at Porto Ferrajo from Leghorn. The interview they sought for was arranged through Count Bertrand and at the ajjpointet time they were, " with- out any form or ceremony whatever,"' ushered into the presence of the Great Man. Twentv-four years later Major \'ivian printed, for private circula- tion only, the narrative now republished by Dr. Rose. We are told the room of modest dimensions in which Napoleon received his English guests was fitted up with old yellow furniture brought from the palace of his sister at Piombino. The conversation lasted from 8.30 to 9.45 p.m., and .Major \'ivian had a unique ojjportunity of studying the personal appearance of Napoleon as it was five months before Waterloo. He w rites : — "We stood, during the whole time, I in.-iy say almost a N.Lpoi. luph IS nez a iicz. for I had my back against the table, and he had advanced close to me, looking full in my face He had on a f,'reen coat, cut off in front, faced with the same colour and trimmed with red at the skirts, and wore the stars of two orders. Under his left arm he held his hat, and in his hand a plain snuff-box. from which he every now and then took a pinch ; but as he occasionally sneezed, it appeared to me that he was not addicted to suufT-taking. His hair was without powder and quite straight ; his shape, inclined to corpulence." We have no jiresent concern with the return from Elba, the Reign of a Hundred Days, or Waterloo. Suffice it to say that at sunrise on Saturday, July 15th I only eleven days short of six months since the interview with \'ivian and Wildman in the '■ yellow "" drawing-room of the Imperial Resi- dence at ElbaK Napoleon, wearing the uniform of a colonel of the Chasseurs lie la Garde, went on board the" Bellerophon."' Exactlv a week later the ship arrived at Plymouth. On the following day (.Sunday, July 23rd). the ship mo\ed to Torbay. w here she remained until the follow ing \\"ednesday (July 26thK On that day the " Bellerophon '" re- turned to Plvmouth. and there on July 31st Na- poleon learned his fate. Early in the afternoon '' of August 7th (Monday), the Emperor went on board the " Northumber- land " at Starpoint. The same day she set sail for St. Helena. During the days spent at Torbay and Plymouth, Napoleon was seen by man\- thousands of persons. It is only quite that the last of those who looked on " Boney " face to face from the crowded cruising round the " Bellerophon "" in Jidy. expired. Twentv vears ago a score of surviving witnesses were still able to testify to the approximate correctness of the familiar picture by Sir t". L. Eastlake. P.K..\., now reproduced as the first of the series of last phase portraits. (See Figure 157.) ^ihikc picturt lately Little boats 1815, April. 1912. KNOWLEDGE. Eastlake was a native of Plymouth, where he was born on November 17th, 179J. He was studying the master- pieces of the Louvre, when the news of Napoleon's landing caused him to quit Paris on ^L'lrch 19th. the same day as Louis the Weli- Beloved took to flight. \\'hen the '■ Bellerophon '" arrived in Plymouth Sound. Eastlake promptly post[K)ned all the work he had on hand, and. " hovering round the ship " in a boat, took a series of rapid sketches of Napoleon as he stood in the gangwav. from which he elaborated a small full-length portrait of the Emperor, and another life-size. The latter was subsequentl\- exhibited i n London. The fine mezzo- tint executed from it b\- C. Turner, is familiar t;tiir.:. .iiiiinated and martial (iKiirc, bnt a heavy clumsy FlGL'KE 160. Napoleon. From a sketch made in April, 1S20. man, moving with a very awUward gait, and reminding us of a citizen lounging in the tea gardens about London on a Sunday afternoon. He was dressed in a large, but plain. cocked hat, a dark green hunting coat, with a star, etc.. on the left breast, white kerseymere breeches and white silk stockings." In another part of the letter he writes :— " Bonaparte must either be very dilTerent in his present appearance and demeanour to what he once was, or we have all been in a great measure deceived. In person he is more like old Wardeniaat, of Batavia, than any man I can name. This resemblance struck us all. To be sure, he has not quite so large a belly, but in other points he does not fall short in size. His face is scpiare, his colour sallow, and his eyes jaundiced without reflecting one ray of light. His visage generally was not unlike that of a Brazilian Portuguese. Though still deficient in animation, his manner was abrupt, rude and authoritative, and the most ungentlemanly that I ever witnessed. While speaking he took snuff or seemed to take it, for there was none in his box, and altogether treated us in the same manner as in his worst humour he was wont to do." Captain John Barnes's "Tour through the Island of St. Helena " was published in London a vear after the Raffles visit. The coloured frontispiece " Napoleon Buonaparte on the Island of St. Helena "' is now reproduced. It must, for obvious reasons, have been engraved by K. B. Fcake from a sketch of earlier date, and does not in any case show the deterioration s])oken of so unHatteringly by Sir Stamford Raffles, who declared he came to Long- wood with a predisposition in favour of the illustrious e.xile. There is no description of Napoleon to be found in Captain Barn^'s common- place te.xt, but amongst the subscribers to the work are Lieut. -Col. Dodgin, C.13., Lieut. Dodgin and Ensign Dodgin, all of the 66th Regiment. Lieutenant (afterwards Captain) Dodgin, as Mr. Watson points out, is responsible for the portrait of Napoleon executed in 1820, now given. (See Figure 160.) Another of Barnes's subscribers was .Mr. Dcnzil Ibbetson. The only uniform Napoleon ever put on at St. Helena was that of the Chasseurs de la Garde, the green coat with red facings, white breeches and top- Iwots, shewn in the Barnes frontispiece ; but on November 28th, 1815, he dropped the uniform (only to be resumed on special occasions, such as his move to Longwood on December 10th, 1815), and put on a cut-away tail-coat, brown or green, with white lireeches and silk hose, a small hat with tricolour cockade and the plcjcj lie and ribbon of the Legion of Honour. The green coat was an old htmtins? I'li.l'Kl, Napoleon as portrayed by Captain Dodgin 66th Regiment in 1820. April. 1012. KNOWLEDGE. 141 costume of the Fontainebleau period and was turned by Saiitiiii when it got very sliahby. Tile cocl-tr>r^ v^ti_-..^L^ ixj S / and Hytfiienc. Erdinj>ton. Thk attention iun\ being given to hygiene and physical culture is ;i \ery hopeful sign of the times. Mr. Gladstone once said that all the time and monr\- spent on training the body and the voice paid a better interest than any other investment. A sound body is needful to all : it is \\ell that English people are waking to this fact, and that there is such a w idc- spread desire to improve the nation's physique. The Swedish system of physical training whicii is found to produce such excellent results in the hands of trained teachers, represents the lifeweirk of Per Henrik Ling, a man of remarkable genius, bdin in Sweden in the year 1776. The fundamental principle of Ling"s Svstem is Figure 166. Arch 1-kxioi the harnidniovis de\'eloi)ment of mind and bodv, the mind to be dominant, the bod\' obedient. Ling taught that right thinking and a right direction of physical strength was of primar\- importance. The following episode in his life, narrated b\- an eye wit- ness, is given by Westerblad, in his book on the Life and Work of Ling. '" Ling once delivered a lecture in which he said that great strength, even the greatest, if badly used is nothing when compared to a little strength well used. At these words an auditor exclaimed, "Your theory is excellent, and I realise its correctness; will you oblige us bv giving a practical proof of it ? " '" At this recpiest Ling hesitated for an instant. r>ut after a moment's consideration he answered, ' I w ill pro\e the truth of my words.' " ^^'ill you bring me a long lance ? ' he continued, addressing those present. They brought him what he asked for. ■ We'll make an experiment with this lance,' he said. ' Which of you are the strongest ? Six of you come forward, please. Seize the end of the lance, please.' Ling went on ' You are six young men and you have at vour disposal a capital lance with a head as sharj) as the blade of a sword. Nevertheless. I bid you attack me, and to run me through with the lance without merc\' — if you are able to do it, you see. I promise not to budge from the spot. When I give the word of command, you may advance. The nt kno\vli:dgi-:. Apkii., 1912. hiiui-hf \ou read ■• At t ul ilircrtK \' ?' is moiiitii towards my breast ! Well, arc I l.iiii; was rrallv iinpiisiti". I|i- 1-IGURE IbcS. HalaiiciiiK. positively increased in height, while his eyes beamed with fire and life. He gave the word ' Go ' and the si.\ young men rushed forward. Ling did not move from the spot, but fixed his eves sharplv on the lance- head and lifted his hand towards his breast. Just as the lance-head was at a distance of a few inches he parried the thrust with his little finger, and the lance-head entered the wall at his side. .\ volle\' of ap|)lause rang through the hall." The truth of this story is x'ouched for by a pupil of his who was present. Ling was well versed in the scientific know ledge of his day, but he also possessed a profound intuitive understanding of the laws of the human organism. His svstem is based on knowledge of anatomical, |)hysiological and psychological laws which were not fully known to science at that time, .\fter a hundred years his theories have received their justification, both from scientific n^search and |)ractical experience. Ling"s system was evolved upon a therapeutic basis. He was first attracted to the idea of systematic exercise by observing the curative efiect on himself. l>ut he was not satisfied to regard these exercisers as a mere vehicle for physical health, he maintained that gymnastics had a higher significance, and placed them among the arts ami sciences. He gave out these new ideas and insisted on the importance of a two-fold national regenera- tion, a regeneration of Swedish manhocjd, and of Swedish poetry. The remedies he proposed in ardent s|)eeches were systematic gymnastic exercises, and a revival of old Scandinavian poetrw His theories met with scornful op|)osition at first : the ilaily papers commented on them in no (Littering terms, designating him as a "charlatan" and a ■'gymnastic harlequin." People trifled with his ideas and laughed at his innovations, Init the innovations increased instead of fliminishing, while he fought for his ideals with intense enthusiasm and power. Ling believed that if gymnastic training could become a national aim and a national ambition, it wduid lie possible to produce health, strength and heautN in youth, to conserve thein through adult life, and prolong them during old age. .Also that it was possible by systematic exercises to correct man\- im])erfections in the body and cause certain functional derangements to yield to this most natural method of cure, pro\'ided each exercise had a definite physiological aim and produced a definite ])hysiological result. He then conceived the idea that an extensive, graduated series of movements Shoulder Mmciiu'iit. could lie devised, suitable for e\ery stage, from weakness up to the greatest strength, adaptable alike to the requirements of little children, to girls as well April. 1912. KNOWLEDGE. as bovs, to women as well as men, and again to the use of those who even in advanced years might w ish to derive the benefits conferred by exercises. The fulfilment of this idea became the object of his lifi'. In time all opposition was broken down, and he succeeded in founding a Gymnastic Institute in Stockholm, with Government aid, and he became its first Director. For man\- \ears Ling worked patiently and earnestly, studying natural science : making himself conversant with the human body in all conditions of health and disease, of weakness and of strength ; learning and realising its possibilities and its limita- tions. He studied the Greek art of g\mnastics, and the different forms of athletics and gymnastics of modern times. He evolved great principles, was entirely guided by them, and rejected all e.xercises which did not come up to their high standard. With a stern hand he put aside all movements for effect, and weeded out the injurious elements of competition and excitement. He made close and practical experi- ment of the effects of different kinds of exercises on the ph\sique in various states, and finally produced an elaborate series of pure, simple and beautiful movements, each having its own aim and producing its own result. Then, with a master liand. he drew Ling's system is divided into four branches, w hich intertwine to some extent : — [{liiictitioinil. — Comprising both apparatus and free Abdominal Movements. up into form and completed his work — a work which has since obtained a unique position as a classical system^of physical education. riiiiik Flexion. exercises for schools and classes, designed to develop the entire physique harmoniously, and to quicken and cultivate the mental faculties. Medical. — Used only for curative and preventive purposes, extensively supplemented by massage. Military. — For the full training of soldiers. The Swedish system has recently been introduced at Aldershot, and into the English Navy. .Aesthetic— To express by pose and gesture every kind of emotion. Swedish gymnastics is a system, and in this fact lies much of its value. The human body being a highly organised system, demands an organised method of culture. The kernel of the Swedish system is (1) the arrangement of the exercises in each lesson ; (2) the progression from the easy to the more difficult, lesson by lesson, as muscle and nerve powers increase. In the educational branch there are nine classes of movements. In every lesson, whether elementary or advanced, the same plan is used. It is found that gymnastic training built on this plan gives the best results, e.g., most progress is made in the shortest time by this method, one exercise preparing for, and leading up to another. The movements follow each other in the correct order, one or more from each class being KNOWIJIDGI-:. Ai'Kii. 1'»12. rtkiiteriiiai m I'lGL'RK 172. Jmupiiif;. iiitroduccil. This is the plan originallx' evol\ed by Ling, and used by all properly trained teachers. The nine classes of nK)\ements are arranged in the follow ing order : 1. Introductory Exkkcisks. — These consist of marching : movements of legs and arms ; easy trunk and head movements ; simple exercises used to gain muscular control and to prepare for those which follow. They (]uicken the circulation ; prepare the bodv for special work : give the teacher an opportunitv to correct faults of posture, and bring teacher and pupils into touch with each oilier, and both into the spirit of the work. 2. Akrii Flkmons (see Figure 106) consist of backward bendings of the trunk in the dorsal region, movements which have a special effect on the thorax; thev contract the muscles of the back, straighten the dorsal spine, elevate the chest and correct its posture. The chest capacity is enlarged, and respir- ation increased b\- reaction. The immediate effect is to draw more air into the lungs and. therefore, to supply more oxygen to the muscles. This is abso- lutely necessary as a preparation for more diiticult nu)\-ements whirb fiillow— tor without this increase of ox\gen tlie\- eitliir could not be well done or might cause strain. There is permanent enlarge- ment of the thorax and elevation of all the organs contained in the tiiorax and alnlomen. This jiroduces Figure 17J. Alighting from a Jump. April, 1012. KNOWLEDGE. a smarter and more upright carriage, a graceful walk and increased power of the organs of digestion. .5. Hhavixi; Mt)vi-:Mi-:NTS exercise and develop the arm and shoulder muscles. Thev include all suspending (see Figure 167) and climbing exercises. The\- also prevent and correct faulty positions of the spine. Hv constantK- practising these two kinds of nio\'e- ments the chest enlarges both lengthwise and in br<-adth. It will be seen that the greatest atlcntion gracefully and easily. After doing the balance move- ment the pupil is again readv for more specific work. .T. Shoi;i.i)i;k (see Figure 169), Back, AND Ni-.ck .Mii\i;Mi-:N"rs strengthen the muscles of the back and neck, thereby giving the head and upper part of the body a more noble poise. They develop the brain, and increase skill of hand. They are also used to correct round shoulders and flat chest. (). AiiDoMiNAi, Movi'.MKNTS (see Figure 170) art'ett till' (lii;istinn anil assimilation of food. Tlic\- FlGlKH i;4. InspiratiDii Kespir;iti)ry Exercises. is given to the development of the chest, for in order to be strong we must breathe deeply and w ell. Oood breathing power means health, strength, endurance and longevity. This is why the Swedish metluxl discards all movements which comjiress the chest. 4. Balaxck Movements (sec Figure 168) come after Heave movements because they equalise the circulation which has been directed to the chest. The pupil gets out of breath from climbing, and so on, and the heart beats more quickly; so we give here a movement which has a calming effect and lessens the heart beat. Balance movements are general in effect, they do not need much muscular effort, but they recjuire concentration of mind. Their special effect is on the nervous s\'stem, which the\- train and strengthen. Balance movements cultivate co-ordination, gi\e consciousness of power, and a reixiseful licaring ; they teach correct poise, and enable the body to move have a good effect on both mind and body through improved nutrition. TIk y dcNclop the waist muscles, and thus give a trimness to the figure. They are used to correct hollow back and protruding abdomen. 7. Latf.kal Trunk MovRMKNTS{seeFigurel71) consist of trunk rotation and sideway flexions. They accentuate the effect of the abdominal movements. They quicken the circulation of the large veins of the trunk and promote the activity of the liver. Thev strengthen the waist muscles and develop ■' Nature's corset." Nature has given us muscles with which to support the body in an upright position. Exercise strengthens these muscles, corsets weaken them. 8. Jumping (see F'igures 172 and 173) and Vaulting develop courage, presence of mind and co-ordination. These exercises develop spring, and from their widespread effect and bracing nature exert an exhilarating influence on mind and body. KNOWLI.DC.K Tlicv iiuliKf (|iiicknL'ss of tlimii,-!)! ;iinl Mclioii. As tlu'y lU'i'il more skill than any ot tiic prcci'din}; tlic\- are plact'cl at tlif ciiii of tlu- lesson, when eontrol of body has been aetinired. '). Kicsi'iKMOKY iiXKKCiSKS (sce Figures 174 and 175>. Consist of deep ins|)iratioiis and ex[)irations for the purpose of increasing the supply of owgen to the system. They are generally accompanied In- some simple arm movements which open the chest. They lessen fatigue and give a sense of repose. Thus every part of the body isscientificalK- trained and strengthened. The organs of resiiiration, circu- lation and digestion receive more attention than the muscular development, so that these storehouses of vitality may be replenished and the brain, nerves and muscles supplied with healthy nutriment. The movements are executed at word of command in order to prev'ent mechanical work and involuntarv imitation. It is an essential principle that each exercise should be completeh' and correctly carried out at the teacher's command, as the best results arc obtained even in a simple movement b\' the concen- tration of the will on the exercise. St\Ic and precision of movement and progress in details are aimed at rather than feats of strengtii. The importance of having fully trained teachers as exponents of the Swedish system cannot be too much emphasised : much harm is being done hv the ignorant and uninitiated, who attempt to teacli so- called '■ Swedish Drill "' after having learnt a few exercises. It must be remembered that while suitable exercises, properly [Jerformed, can and do correct faulty postures, unsuitable and even suitable oni'S incorrectl)' performed produce, and exaggerate, the very |)ostures and deformities of the bodv for which they are meant to be corrective. Unless a teacher is both trained and observant more harm than good is likely to be done bv teaching gymnastics. .As Dr. Shrubsell says: — "No one would dream of placing a teacher who had never learned mathematics in charge of a mathematical class, where the worst that could happen would be failure to acquire knowledge, a purely negative result : whereas often untrained teachers are set to put a class through gymnastic e.xercises, with the grave risk of producing a permanent, positive result in the direction of bad carriage and even bodilv deformity. Two years is none too long in which to learn both the principles of the subject and their api)lication. Slight knowledge is almost more dan- gerous than none at all." Swedish gymnastics should constitute a [)art of the ordinary school work, and a place should be given for daily lessons in the timetable. Being less recreative, and presenting a corrective element, they are not intended to take the place of games. They make considerable calls on the mental as well as the bodil\- activities, and to produce the best effects should be taken during morning school and not relegated to the last period of the afternoon. It is instructive to notice that during the thirty years the Swedish system has been in general use in Scandinavian schools, the average stature and weight of the children have shown a marked increase. [NOTI-:. — We had the pleasure of going down to the .\nstey College and seeing for ourseh'es the most interesting and successful work of the students there. Birmingham is only two hours' journe\- from Euston on the London and North-Western Railway, and a local train carries one on to Chester Road, lirdington, which is practically in the suburbs of the citv. — Eds.] II". sri'in' oi' PRiMirix'!- mcsic. Dr. C. S. Myi-;ks gave a lecture on " Primitive .Music " at the Ro\al Anthropological Institute on Tuesday, March 19th, when the Presitlcnt. Mr. •Alfred P. Maudslay, was in the chair. In this pa])er the chief objects and nu'thods of studying the music of primiti\c peoples were described, illustrated by examples from Horneo (Sarawak), Torres Straits (Murray Islandersi and Ceylon (Veddas), the music of which Dr. .Myers had personall\' investigated. Man\- of the songs were exhibited by means of the phonograph, — an instrument, the importance of which, even to the most musicallx'-gifted ethnologist working " in tiie field," was strongly emphasized. The structure and details of other songs were indicated by various lantern slides in which (i) the music was reduced to our own notation : (ii) the nature and fre(]Uency of the various intervals employed were demonstrated, the inter\als being exjjressed in ratios of xibration freipiencies or in " cents," /'.<.'., hundredth parts of our tem[)ered semitone, and (iii) the various scales deduced from the songs were shown. Detailed descriptions were gi\en of the technique of analysing phonographic records and of the graphic method introduced hx Dr. .Myers for recording " in the field " the occasionalK" baffling rh\thnis. met with especially in the drum accompaniments to primitive music. The music of the Nlurray Islanders and of the Todas was analysed to show (i) the wide dift'er- ence even between such verv simple forms of music belonging to two distant peoples ; (ii) the different lines of musical development traceable within different communities; (iii) the great importance, alike for ethnology and for musical history, of studying the process of diffusion of the various styles of music, and also of musical instruments, in regard to their form, their intervals and their absolute pitch. NOTES. ASTROXOMV. By A. C. D. CROMMlil-lN, B.A., D.Sc, F.K.A.S. I HAVK decided to use my column this month to give an explanation of the Harvard svstem of classification of star- spectra, which is now in general use. .-\5 spectra are often quoted simply by their letters in this classification, and as the full description in Harvard Atnials, \'o\. X.XVIII, is probably not readily accessible to many of our readers, it seems likely that it will be convenient to give a summary of it here. The m.ain classes of spectra are denoted by the letters O, B. A. F, G. K, .\f, X, which originally followed each other in alphabetical order (in the Draper Catalogue), but have now been put into the order which is conjectured to be the chronological order of their life-history. The fact, recently discovered by Professor Campbell, that average radial velocities increase as we pass from the beginning to the end of this set of letters, is a distinct confirmation of the theory that it is a true chronological sequence. Besides the above eight letters, P and O are used, the former for gaseous nebulae, the latter for peculiar spectra having bright lines. Small letters following the capital ones, as Oa, Mb. and so on, indicate sub-divisions of main classes. Where two capitals are used with a numeral between, as BIA, B3A, B5A, the meaning is that the type is intermediate between B and A, and one-tenth, three-tenths, five-tenths respectively of the interval from the former to the latter type. We now proceed to the description of the types. The letter O in general corresponds to Secchi's Fifth Type. Oa. — There are no very bright stars of this type. The spectra consist of bright bands on a faint continuous background. Two of the bright bands are hydrogen ones, 4101-8 = Ho, 4340-7 = H7. A fainter one at 4471-8 appears to be helium. There is a broad con- spicuous band at 4633. Ob. — There are no very bright stars of this type. Spectrum similar in general character to Oa, but positions and intensities of the bands differ. Several hydrogen lines bright, including Ht, Ho, H7, H/i; no helium lines seen. .\n intensely bright band has centre at 4688. Oc. — Xo very bright stars of this type. The bands are much narrower than in Ob. Ho, H7, H/S, 4471-8 (helium) and 4688 arc again bright. Od. — Typical star i Puppis. All lines are dark except 4633 and 4688. which are bright. The dark lines are narrow. Hydrogen lines dark. Only four other dark lines. Oe. — Typical star, 29 Canis Maj. ; like Od, but far more dark lines. Oe5B. — Typical stars, t Can. Maj., land S' Orionis. No bright bands. Resemble Oe in hydrogen spectrum, B in helium spectrum. K (calcium) sharply defined. B. — This is sometimes known as the " Helium " or " Orion " type. Typical stars, e. (, 0 Orionis. Helium lines more conspicuous than hydrogen ones. BIA. — Type, f* Centauri. More faint lines than in B. Helium lines intense, including D,. B2A. — Type, y Orionis. The helium lines attain their maximum intensity in this class. B3A.— Types, a Pavonis, t' Orionis. Diminution in strength of " Orion " lines. B5A. — Type, 1 Tauri (Alcyone). Helium still present, but less conspicuous ; hydrogen, calcium, and so on, more con- spicuous. B8A. — Type. 7 Gruis. Hydrogen lines still increasing in intensity, and are hazy ; twelve " Orion " lines still seen. The solar lines seen in Class A now begin to appear. B9A. — Type. X Centauri. Spectrum like A class, with addition of helium. A (Sirian stars). — Types, Sirius and Vega. Secchi's First Type. Hydrogen lines attain their maximum strength in this and in the next class. Calcium fairly conspicuous, and there are ninety-three solar lines. \Z\'. — Type, 1 Centauri. Calcium and solar lines are stronger than in last. A3F. — Type, r-' Eridani. Calcium more intense; solar lines more numerous and more intense. ASF. — Type, "■ Pictoris. Hydrogen begins to weaken, solar lines continue to strengthen. All lines somewhat hazy. F. — Type, a Carinae. This class is intermediate between Secchi's first and second types. Hydrogen only half as intense as in A. Ultra-violet spectrum strong. Three hundred and twenty-six solar lines present. F2G. — Type, ir Sagittarii. The G band in the spectrum grows stronger. F5G. — Type, Procyon. Hydrogen, though only half as intense as in Sirius, is still two or three times as intense as in Sun, while solar lines are fainter and fewer than in Sun. F8G. — Type, a Fornacis. Resembles following class, except that hydrogen is twice as intense. G (solar stars). — Secchi's second type. Type Capella. Hy- drogen one-fifth as intense as in Sirius. The calcium H,K lines, and the band G are the most conspicuous features. G5K. — Types, a Reticuli and /S Corvi. Hydrogen still grows weaker, and absorption at violet end begins. K. — Intermediate betw-een Secchi's second and third types. Types a Phoenicis and f Scorpii. Hydrogen one-twelfth as intense as in Sirius. The K line of calcium attains its maximum intensity in this and the next class. There are brightish bands whose limits are 4470 to 4525, 4614 to 4648 in this and preceding class. Arcturus belongs to this class; its spectrum resembles that of a sunspot, so that it is probably much more spotted than the Sun. K2M. — Type, " Librae. Like following class in intensities of solar lines and absorption at violet end. But the G band is still continuous as in Class K. K5M. — Type. Aldcbaran. Like Secchi's Third Type. Hydrogen lines one-twentieth as intense as in Sirius, and are inconspicuous among solar lines. The spectrum beyond K too faint to photograph. H,K are conspicuous. The G band is broken up into lines with bright intervals. There are the same brightish bands as in Class K and some others. Ma. — Types, j3etelgeux and 7 Hydri. This is Secchi's Third Type. Spectrum banded. There are now well marked bands from 4762 to 4954, and 4954 to 5168, which were faintly seen in K5M. "The edges 4762, 4954, 5168 are brighter than the adjacent continuous spectrum, and the change in intensity from these edges towards the end of greater wavelength is abrupt." There are bright bands, 4470 to 4525, 4556 to 4586, 4657 to 4668. Hydrogen lines similar to Aldebaran. The H,K bands are barely seen. The hnes that formed the band G in Classes G to K are now well separated. Antares is of Class Ma except that hydrogen lines H)3, H7, H5 are stronger, and H-n, Hfare present as in Class A. Betelgeux has also stronger hydrogen lines than the normal Ma star. Mb. — Typical stars, 7 Crucis, o Librae. The abrupt change of light from the edges of the bands towards the end of the spectrum of greater wave-length is more marked than in .Ma. Numerous bands brighter than adjacent portions of the spectrum are present. Hydrogen even fainter than Ma, and is only one-thirtieth as intense as in Sirius. Line 4227 reaches its maximum intensity in this class. Md. — This class resembles Mb, except that HS, H7, H^ (hydrogen lines) are bright. The lines of the band G are even less conspicuous than in Class Mb. o Ceti (Mira) is of this class. N. — This corresponds to Secchi's Fourth Type. It consists of small red stars with banded spectra, the bands being sharply defined at the red end and fading away gradually at the blue end (the opposite to the Third Type). The bands are due to carbon and cyanogen; those of the Third Type have been identified by Fowler with titanium oxide. 150 KNO\VLi:i)Gi:. Al'kli.. 1912. It will 1h' rememlicrt'il that (as Mr. ICdcliiiKton rccciilly pointed out) tlif M stars are ititriiisicaily faint, liaviiij; strongly absorbiiiK atmospheres; conse<|nently. they cannot be seen at a distance, which is the reason why the Sun's nearer neigbbours contain an apparently nndne proportion of M stars : they are probably really as common in the more distant p.irts of space, bnt too faint for us to see. Conversely the li stars are all very distant, and are probably .ictually rare in space, bnt beintj of great intrinsic brilliance they are seen at ininicnsc distances, and so appear in exaggerated numbers in our catalogues. The Sirian type of spectrum of (Galactic stars would also be e.Yplained by stars of the solar type being invisible at such a great distance. A NfiW STAR. — A new star of the fourth magnitude was discovered at Kiel on March IJth. It is stated to be near Thet.i ("ieminornni (the same region where Professor Turner's Nov.i .ippeared in March, 1903). BOTANY. By Professor F. Cavf.ks, D.Sc, F.L.S. POTASSIL'M IN PLANTS.— Some interesting results bearing upon the localisation and function of the element potassium in plants have recently been published by Weevers (Rec. Trav. Nccrlaiul. , \'lll.. I'Jll), who made numerous tests by means of Macallum's method for the detection of potassium — the jjrecipitation of potassium-cobalt-nitrite and the conversion of this into the black sulphide of cobalt by treatment w^ith anmioniuni suljjhide. Weevers found potassium in the tissues of all the plants he examined, covering a wide range, excepting in the blue-green algae (Cyanophyceae) which gave negative results. In no case, however, was potassium to be found in the nucleus, even when abundant in the protoplasm of the cells. Even more surprising, in view of the statements of previous writers, was the entire absence of this element from chlorophyll and from the chromatophores themselves. The greater portion of the potassium was found in the cell-sap vacuoles. In every case the potassium was present in a form soluble in water, and it could be extracted by means of water or dilute alcohol, but was insoluble in ether. In the flowering-plants, this element is most abundant in the ground-tissue (parenchyma), especially in the growing-points and in reserve-food organs. It is also present in the living parenchyma of the wood and barU of trees, and particularly so in the growing-layer (cambium) and in the medullary rays, which appear to serve as storeplaccs of potassium for the growth of new shoots. As to the functions of potassium, Weevers concludes from his observations that this element plays little or no part in the process of carbon assimilation, but is probably concerned in the building-up of protoplasm at the growing-points and in growing tissues generally. In the leaves, it probably helps in the synthesis and also in the breaking-down of proteins. BIOLOGY OF LICHENS.— An interesting paper by Tobler on the mode of nutrition of lichens was noted some time ago in these colunms (" Knovvi.kdgk," 1911, page 276). The same writer ijithrb. fiir iciss. Bot., 1911) has since published a longer paper — the first instalment of what promises to be an important series of researches — in which he deals with the relation of two so-called " lichen parasites," both belonging to the Peziza family of fungi, to (1) the lichen host itself, to (2) the alga component of the lichen, and to (3) the substratum on which the lichen grows. The fungus Phacopsis viilpiita grows on the lichen Eventia viilpina. an alpine species. Tobler sectioned the fungus and lichen together in paraffin, and traced the course of the Phacopsis hyphae in the lichen thallus. These threads reach the enclosed alga cells and grow closely around these. Where the Phacopsis is best developed on the lichen, the alga cells are entirely absent ; on other regions the algae are surrounded singly or in groups by the Phacopsis threads ; in other places the hyphae of both Phacopsis and the lichen- fungns are foimd entwining llic .ilgae. Hence the Phacopsis threads can in lime reach the algae in certain areas of the lichen thallus and displace the threads of the lichen-fungus itself. The algae apparently multiply more rapidly for some time after the Phacopsis threads reach them, but they finally disappear entirely where these threads are most profusely developed. The Phacopsis threads then spread laterally until large portions of the Evcniia cortex are cut off from the central tissue (mednll.il and eventually die. the invading threads then penetrating inlr) the dead cortex and also into the medulla of the lichen. Tobler concludes that the Phacopsis is at first a " parasytnbiont," living in partnership with the lichen and later becomes parasitic. The second parasite investigated. Karscliia dcstructans. grows on the th.illus of Cliaciiothcca clirysoccphala. a bark- inhabiting lichen with thin crustaceons thallus. 'ihc Karscliia penetrates into and through the lichen th.illus and into the bark itself, on its way entwining and destroying alga cells and displacing and destroying the hyphae of the lichen. Finally, however, the Karschia threads enter the bark and then pro- duces its spore-fruits. Hence Karscliia is successively a parasymbiont, a parasite, and finally a saprophyte. From his study of these two fungi, out of about four hundred known to grow on lichens, Tobler concludes that there is no sharp distinction between parasites, parasym- bionts, and saprophytes among these lichen-infesting fungi, since a single species may exist in all three conditions during its life history. He also claims that his researches break down the supposed sharp boundary between lichens and fungi, and his interesting observations certainly appear to support the view that the biological distinction between lichen-fungi and other fungi cannot serve any longer to main- tain the lichens as a separate group of plants. That is to say, followed to their logical conclusion, Tobler's results lead us to the view that the fungus alone constitutes the lichen, THE BUCKWHEAT SEED.— In many text-books the seed of Buckwheat, so commonly used as a type for germination in elementary botanical teaching, is said to contain perisperm, i.e., nutritive tissue derived from the nucellus tissue lying outside of the embryo-sac and within the integument of the ovule, and this character has been regarded as an indication of affinity between the buckwheat family (Polygonaceae) and the Pepper family (Piperaceae). Stevens {Bot. Gaz.. 1912) has made a carefulstudy of the development and structure of the Buckwheat seed, and finds that it contains no perisperm at all. The early development of the embryo agrees closely with that of the familiar and often- figured Shepherd's Purse iCapsclla), and accompanying the growth of t'oe embryo there is rapid development of endosperm from the contents of the embryo-sac. The nucellus is at an early stage present as a thin, but actively-growing layer, just within the integument, but as the seed matures this incipient perisperm is obliterated and in the ripe seed it is represented only by crushed remains of cells. .'\NTS .^NI) PL.'XNTS. — .An interesting paper on this sub- ject has recently been published by Ridley (.4/i;i. Bot.K who, as director of the botanical gardens at Singapore, has had exceptional facilities for the study of the myrmecophilous plants of the eastern Tropics. The cases of symbiosis between ants and plants dealt with in this paper fall into three categories. Many such plants [c.}>.. Dischidia raHicsiaiia and several Rattans) afford shelter to ants, either within the leaves and flowers or in special hoUowed-out organs such as tubular stems or thorns, but the ants get no food from the plant, nor do they appear to benefit the latter, except that in a few cases the ants may bring about pollination when they nestle in and about the flowers, c.^.. in Goitiothalaiiius ridlcyi. In a second class of myrmecophilous plants there appears to be a relationship, which is mutually advantageous, between many epiphytic ferns and orchids, whose roots afford shelter, and the ants, which in making their nests bring up large quantities of soil and heap it round the base of the plants, e.g.. Apkii., IQi: KNOWLEDGE. 151 Thaiiinopten's tticiiisavis. Platyccritiiii bifonnc. and a considerable number of orchids. A third class of two small trees, Macitraiifia triloba and M. griffitliiiina. whose hollow stems are pierced and tenanted by ants. These trees have persistent stipules which have glands secreting wa.\y granules, these being gathered and used as food by the ants. In return for this food and shelter, the ants protect the trees from the attacks of larvae. ALCOHOLIC FKRMKNTATIOX.— Some interesting re- sults have recently been obtained from further work upon the fermentation of sugars by means of yeast. Harden and Norris [Proc. Roy. Soc, B 82) have found that many yeasts that do not ferment the sugar galactose acquire the property of doing so after being cultivated for a time on a medium containing this sugar. They also find that the juice expressed from such a yeast is capable of fermenting galactose, and that the addition of phosphates to the fermentation mixture causes an acceleration of fermentation similar to that observed in mixtures of glucose, fructose, or mannose and yeast juice on the addition of phosphates. In each case, the phosphate is present in the form of an organic compound, from which it is not precipitated by magnesium citrate. Small quantities of soditun arsenite also accelerated fermentation. .As to the nature of the compound formed when a phosphate is added to a fermenting mixture of yeast juice and sugar, ditferent workers have held that (1) the compound is a hexose phosphate containing two phosphoric acid residues; (2) it contains only one phosphoric acid residue, since the osazone obtained from it has only one such residue; (3) it is a triose phosphate. In a recent paper dealing with the mechanism of fermentation. Young {Biochein. Zeitschr., 1911) brings forward evidence to show that the compound is a hexose phosphate with two acid residues, this contention being based largely on the composition of the barium salt of the compound and on the behaviour of its osazone. Neuberg and Tir {Biochein. Zeitschr., 10111 have greatly extended our knowledge of the action of yeasts upon sub- stances other than sugars. The chief substances which are fermented in this way, with the evolution of carbon dioxide, are the connnon plant acids occurring in fruit juices, also various components or products of the yeast-cell, e.g., fatty acids, glycerine, and lecithin. CHEMISTRY. By C. .\iNswoRTH Mitchell, B.X. (Oxon.), F.I.C. BACTERIAL DECOMPOSITION OF ARSENIC COM- POUNDS.— .\rsenic is usually regarded as a powerful antiseptic agent — so much so that it will preserve organic tissues from undergoing decomposition for many years. Thus, in the case of the arsenic-eaters of Styria the system becomes so saturated with the drug that when the graveyards are opened the bodies of those who had acquired the arsenic habit may be distinguished by their almost perfect state of preservation. There is also evidence to show that arsenic- eaters arc p.irticularly immune from infectious diseases. It is, therefore, surprising to find that certain bacteria can not only live in a strong solution of sodium arsenite, but can also effect its oxidation. This remarkable phenomenon has been discovered by .Mr. A. V. Fuller, and its practical in\portance is emphasised in a circular published by the U.S. Department of .Agriculture, Bureau of .-\nimal Industry. (No. 182. November 9th, 1911.) It was found that arsenical dipping fluids used for washing sheep showed an apparent loss of ar.senic after standing for some time in the vats. Experiments proved that this was not due to purely chemical reactions, but was caused by a spontaneous oxidation of the sodium arsenite to sodium arsenate, which escaped detection in the method of estimation employed. The oxidation was shown to be brought about by micro-organisms, which have not yet been isolated or identified. So rapidly did it take place under favourable conditions as to temperature, nature of nutrient .substances present, and so on, that in some experiments the arsenic had been almost com- pletely oxidised in the course of a few weeks. Thus, for example, a sample of dipping fluid which contained sodium arsenite in a proportion corresponding to 0-236 per cent, of arsenic trioxide was mixed with suitable nutrient media and inoculated w^ith sheep dip in which the oxidising process had begun. The flasks containing the inoculated liquids were kept for a month at the ordinary temperature in the dark, being meanwhile shaken from time to time to promote the oxidation. Flasks containing the same dipping fluid which had been sterilised by heat were also exposed to the same conditions. At the end of the period it was found that the liquid in the control flask contained 0-222 per cent, of arsenic trioxide, whereas in the case of the inoculated samples the proportions ranged from 0-006 to 0- 198 percent. Owing to the varying conditions to which arsenical dips are exposed in practice, it has not been found possible to fix any limit of time during which a wash might be regarded as materially unaltered, and the circular therefore advises that all arsenical sheep dips should be discarded after being exposed for more than a few weeks, unless it is shown by a chemical estimation that they contain their original amount of arsenic trioxide. SILOXIDE: A NEW GLASS.— Claim is made by MM. WolfBurckhardt and Borchers, in a recently-published F'rench patent (No. 432,786 of 1911), for a new glass which is prepared by fusing together pure natural silica with oxides of the silicon-carbon group, preferably titanium or zirconium oxides or a mixture of the two. The resulting products are termed " Z-siloxide " or zirconium glass, and '" T-siloxide " or titanium glass, and have many advantages over pure quartz glass, although they do not possess the same beautiful lustre. An experimental investigation of the new glass has been made by Mr. F.Thomas (Chem. Zeit., 1912, XXXVI, 25), who finds that it is much less liable to undergo devitrification, and that it is less affected by the action of alkalies or other chemicals than quartz glass. The strongest zirconium glass was that containing one per cent, of zirconia, while the titanium glasses (containing 0-1 to 2 per cent, of titanium) were inferior to quartz glass in their power of resisting compression, but were still better than the zirconium glasses in resisting the action of heat. The new glass can be worked by the methods in ordinary use in the manufacture of glass. AMORPHOUS SILICON.— A black silicon sulphide obtained by fusing together in an electric furnace a mixture of ferro-silicon and sulphur has been described by Dr. L. Cambi (Chem. Zeiitralbl, 1910, II. 1863). When this is hydrolysed it yields a chemically-active product, which has been found (Afti Accatt Lined, Roma, 1911, XX, 440) to consist, in the main, of a variety of amorphous silicon. A fairly pure sample, containing ninety-six per cent, of silicon, had a specific gravity of 2 ■ 08, while the variety of amorphous silicon discovered by Vigouroux has a specific gravity of 2-35. This new form of silicon is a bright reddish -yellow body, which, when heated for an hour at 900*^ C, in the absence of air, is transformed into a heavier brown product, closely resembling V'igouroux's silicon. The impurities in the active amorphous silicon consist of hydrogen and oxygen, which are probably in combination with the silicon. PROPERTIES OF PURE VANADIUM.— Pure metallic vanadium has been prepared by Messrs. O. Ruff and W. Martin, and a description of the methods employed and the properties of the product are given in the Zeit. angew. Chem. (1912, XXV., 49). By fusing vanadium trioxide with a mixture of carbon and aluminium in the .alumino-thermal process, a product containing from ninety- five to ninety-nine per cent, of vanadium was obtained. Or vanadium carbide was first prepared by fusing together in carbon crucibles (heated to a temperature of 2800°C.) a mixture of vanadium trioxide and carbon, and then fusing (at 2000°C.) a mixture of this vanadium carbide and vanadium trioxide in an electrically-heated furnace. The melting-point of the pure metal was 1715°C., and its specific gravity at IS-y^C. was 5-688. In the fused condition it w-ould dissolve either vanadium trioxide or carbide, to form mixtures of higher melting-points than the metal. KN'0\VLi:i)Gi:. APKII.. 1<>12. By G. \V. rYRKE-Li., A.K.C.Sc, F.G.S. Tin-; INVAKIAUILITY OK IGNEOUS KOCK ASSOCIATIONS. — An intorostiiiK case of innKiiiatic difTei- entiatioii lias been ilesciibed fri)iii Tripyraniid Mountain, New Hainpsliirc. l>y Professor L. V. Pirsson and \V. X. Rice {Aiiicr. Joiirii. Sci. \\m\-'S\:iy, 1911), which also raises the (jiieslion as to how far certain associations of i(jneons rocl- Papers. The frequency with which a second edition or reprint of many of these publica- cations is demanded is proof of their utility to the public and an example of the excellent economic work that can be carried on b>' a national survey when a broadrninded Govern- ment provides adequate funds for its proper upkeep. One of the latest of this series to achieve a second edition is Paper No. 255, on " Underground Waters for Farm Use," by M. L. Fuller. This paper deals in simple language with every con- ceivable phase of water-supply on farms and cannot fail to be of immense practical value to English-reading farmers every- where. Seventeen well-chosen plates and twenty-seven dia- grams help out difTicult places in the text. Mr. I^'uller gives an interesting note on his own experience of the divining rod, the simple forked branch of witch-hazel used by the so-called water-witches as an indicator of underground water. We (|uotc his remarks (page 15): "In ex|)eriments with a rod of this type, the writer found that at certain points it seemed to turn downward independent of his will, but more complete tests showed that this down-turning resulted from slight and. until watched for, unconscious muscular action, the effects of which were communicated through the arms and wrists to the rod. No movement of the rod from causes outside of the body could be delected The use- lessness of the divining rod is indicated by the facts that it may be worked at will by the operator, that he fails to detect strong water-current in tunnels and other channels that afford no surface indications of water, and that his locations in limestone regions where water flows in well-defined channels are no more successful than those dependent on mere guesses. In fact, its operators are successful only in regions in which ground water occurs in a definite sheet in porous material or in more or less clayey deposits, such as pebbly clay or till. No appliance, either mechanical or electrical, has yet been devised that will detect water in places where plain common sense will not show its presence just as well. The only advantage of employing a " water-witch ' .... is that crudely-skilled services are thus occasionally obtained, since the men so employed, if endowed with any natural shrewdness, become through their experience in locating wells better observers of the occurrence and movements of ground water than the average person." BRITISH PILLOW-LAVAS.— Two further occurrences. in the Tavistock- Launceston area, and in the Kilbride Peninsula, Mayo, have been added to the already long list of pillow-lavas, which are so well-developed upon several Palaeozoic horizons in Great Britain. These rocks usually belong to the peculiar group of the spilites, in which felspars rich in soda form the major part of the rock, w-ith subordinate augite. occasional olivine, and some glassy base. A distinctive micro-structure is shewn by the felspars, which are long, acicular and pointed, with lluidal arrangement, but often also variolitic. The spilites are associated with albite-diabase. minverite, picrite, (juartz- diabase, keratophyre and soda-granite, forming a well- characterised group of rocks named by Dewey and Flett the "spilitic suite." The new Devonian occurrences are fully described in a recently-issued Survey Memoir on "The Geology of the country around Tavistock and Launceston." They belong to two horizons, the Upper Devonian and the Lower Culm Measures. Many of them are highly decomposed and rendered schistose by pressure, so much so that it would be more correct to describe them as schalsteins. The intrusive rocks associated with the spilites are quartz-keratophyre. minverite, picrite. and quartz-diabase. The Irish pillow-lavas are described by Mr. C. I. Gardiner and Professor S. H. Reynolds, in a paper on "The Ordovician and Silurian Rocks of the Kilbride Peninsula (Mayo) " {Q.J.G.S.. February. 1912), an addition to the important series of papers by these authors on the Palaeozoic Rftcks of the W'est of Ireland, The pillow-lavas are here associated with sediments of .\renig age, and belong to a widespread and extensive series, Spilite and felsite breccias occur proving the presence of an acid magma at no great distance, although no acid lavas have been found in the area. Later on, but almost certainly in .\renig times, one large and many small intrusions of felsite took place. No contemporaneous basic intrusions appear in the area. At an early post-silurian date, however, lime-bostonites and labradorite-porphyrites. which may form part of a later spilitic suite, were intruded. Ordovician pillow-lavas are also known in the Girvan- Ballantrae district of Ayrshire, and Megavissey and Mnllion Island in Cornwall, pointing to a spilitic petrogiaphical province of enormous extent covering the Western British area in Ordovician limes. April, 1912. KXO\VLi:i)GE. METEOROLOGY. By JOH.N A. Curtis, F.R.Met.Soc. The weather of the week ended February 17th. as set out in the Weekly Weather Report issued by the Meteorological Office, was very dull generally, with a good deal of fog and mist in places. Temperature was above the average in all districts, the excesses varying from 2°-7 in Scotland, K., to 5° -4 in England. E. Maxima above 50° were recorded in all parts ol the country, the highest being 57° reported at Tottenham. Llandudno and Killarney. The minima were below the freezing point in all districts except England. E., and the English Channel. The lowest reading reported was 25° at West Linton on the 11th. In the Channel Islands the temperature did not fall below 38°. On the grass readings down to 18° at Dublin and 19° at Aspatria, were observed. Rainfall was slightly in excess in England, N.E.. the Midlands. and England, S.E.. but was in defect elsewhere, the greatest defect being in Scotland, N., where it was but one-fourth the average amount. Simshine was less than usual in all parts except Scotland, N. In that district the daily duration was l-l hours (24 "ol, while in the English Channel it was 2-7 hours (27 %). In England. N.E., however, the daily amount was only 0-2 hour (2 %). At several stations the week was sunless. Westminster reported 0-7 hour (7 %). The mean temperature of the seawater round the coasts varied from J7°-9 at Burnmouth to 46° -7 at Salcombe, and was, as a rule, a little above the normal. The week ended February 24th was cloudy and damp, with fog and mist on the coast. Temperature continued high and was again above the average in all districts, by as much as 7°-4 in England. E. A maximum reading of 60° was recorded at Birr Castle. Ireland, on the 22nd, the next highest reading being 58 at Hawarden Bridge, near Chester, on the same day. In Jer.-^ey the highest reading was 56°. Frost was recorded in all districts except the English Channel, where the minimum was 39". The lowest of the minima reported was 25° at Llangammarch Wells, but the thermometer on the grass at that station fell to 20°. .\X Dublin the grass thermometer was as low as 19°. The temperature at one foot below the earth surface was above the normal at all stations and by as much as 5' in the South-East of England. Rainfall was in excess in all districts except England. X.W., the diftereuce from average being considerable in places, especially in Ireland. Sunshine on the other hand was in defect in all districts except Scotland, W., where it was slightly in excess. The sunnUst district was Ireland, S., with a daily value of 2'8 hours (28%). At Westminster the daily amount was only 0- 1 hour or 1 per cent. The temperature of the sea water was higher than usual, and the mean values varied from 38°- 0 at Burnmouth to 48°- 1 at Salcombe. The week ended March 2nd was very unsettled, with rain on most days. In the extreme N. and N.W. the rain was sometimes heavy. Temperature continued above the average, the excesses above the normal being very high, 10° -0 in England, E., and nowhere less than 6°-2. The maxima, however, did not exceed 60° at any station, but this value was recorded at many stations between York and Jersey. The high average was due to the high minima, and in each district the average of the minima this week was higher than the normal average temperature, the excess in England. E., being as much as 4° • 6. On the grass the lowest readings recorded were 23° at Rauceby and 24° at Crathes and Markree Ciistle. The earth temperature at one foot depth was higher than normal at all stations. R.ainfall was slightly below the normal in the Midlands and North-Eastern districts, but was in excess elsewhere, especially in the North. .-Vt some stations the total precipitation was more than twice as much as usual. Thus, at Stornoway the total was 2-84 inches as compared with the average of 0-99 inch, and at Newton Rigg 1-38 inches compared with the average of 0-67 inch. Sunshine was below the normal in all parts, the sunniest district being the Enghsh Chaimel with a daily mean of 3-4 hours (32%). Of the individual stations, Torquay recorded the most sunshine, 3-8 hours per day (36%). The sea temperature varied from 38° at Burn- mouth to 50° at Plymouth and Scilly. The week ended March 9th was again unsettled, with frecjuent rain at many stations in the West and South-West. A feature of the week was a well-marked line squall that travelled from the S.W. of Ireland to the S.E. of England on the 4th, accompanied by sharp thunderstorms and exceedingly heavy gusts of wind. The maximum velocity recorded in this stiuall was eighty-nine miles per hour at Falmouth (Pendennis), but a few hours later a gust of ninety-eight miles per hour was recorded at the same station. Temperature was again above the average in all districts, the excesses, however, being of less amount than in the preceding week. The high average was due as before to the high minima, for the maximum nowhere exceeded 58° which was the reading at Jersey on the 5th. In most districts the maxima for the week were below 55°, and in Scotland, W., the highest reading was only 50°. The minima, on the other hand, were high and there was but little frost. The lowest reading recorded was 28° at Nairn and at Balmoral on the 8th. In Scotland, W., the temperature did not fall below 34°, and in the English Channel the lowest reading was 36°. On the grass, however, severe frost was registered, the readings falling to 20° at Crathes and to 21° at Plymouth and Southampton. .At a depth of one foot the earth was much warmer than usual. Rainfall was slightly below the average in Scotland, N. and E., but above it in all other districts. In England, S.W., and the English Channel, the totals were nearly three times the usual quantity. The week was much more sunny than those which immediately preceded it, and daily averages were reported up to 5-1 hours (46%) in Ireland, S. All the districts showed excesses except England, N.E., and the English Channel, which were slightly in defect. The mean sea temperature ranged from 39° -9 at Burn- mouth to 49' -0 at Newijuay. which was considerably above the average. The past "Winter," that is, the period of thirteen weeks. December 3rd. 1911, to March 2nd, 1912, has been on the whole warm and wet, but dull. In England, S.E., of the thirteen weeks six were unusually warm, five normal and two cold ; nine weeks were unusually wet, three normal and one dry, but only two weeks unusually sunny, one normal and ten dull. MICRO.SCOPV. coiidiicted with the assistance of the following Diicroscopists : — Akihur C. Bankield. The Rev. E. W. Bowkm.. n. Ca .•iRTH UR Em! [ AN[- 1, F. R.M.S. RiCHARU T. Lew IS, F. R.M.S. Chas F. Rou ■SSE! •ET, F. R.M.S, D. J. Sec >L'KK lEI.U , F. R.M.S. F. .L.S., F .R.M.S. AN ATTRACTIVE "COMMON OBJECT."— An inter- esting but perhaps little-known micro-object, plentiful in spring, may be found at the base of old dead nettle stems. The stem should be carefully drawn out from the ground after first loosening the earth round it. On examination it will be found in nearly every case, that under the cuticle just above the root, there are a number of little black points. With a moderate magnification they are seen to be flagon or bottle shaped bodies ; when not crowded many are very symmetri- cal in form, while others owing to pressure and crowding are more or less mis-shapen. They have a narrow neck which pierces the cuticle, appearing on the exterior as a minute papilla with an orifice at the summit. These are specimens of the ascomycetous fungus Sphaeria acuta. If the stem supporting them is carefully dried they form an attractive object for a low power — say one inch or one-anda-half inches — under incident light especially with a binocular. With vcrv little trouble a preparation showing their minute struc- ture may be made. For this purpose they should be detached with as little injury as possible, and should be soaked in strong spirit for some hours ; then a little glycerine (dilute) 154 KNOWLKDGi:. Al-Rll., 1912. may bo addcil and llifv can be left in this mixture for any length of lime convenient. After a few days, they will lose their brittleness. and c.in be opened out with needles. They will be found to be filled with long narrow sausage-shaped bodies, with very thin transparent walls, sometimes ditlicnit to see. These are tisci and are interspersed — packed in as it were — with fine threads — {he panipliyscs (Figure 176, a). The asci each contain eight rather long, generally slightly curved spores, pointed at each end. and divided by from five to eleven cross walls (Figure 17fi, b.) They arc arranged in a double row with the ends overlapping, frequently in a spiral manner, see Figure 176, a. It may happen that the fiasU-shaped body contains only minute simple spores, free in the interior without any asci. in which case the specimen is an incom- pletely developed form of the same organism and has received the name Apospaeria acuta — vide Dr. Cooke's " One thou- sand objects for the microscope " No. 336. .iMmost certainly another form exists also, and is probably included in the genus Macrosporititu, as a species closely related to the one we are considering (Sphaeria herbariiiii) is known in one stage as Macrosporiiiin sarciniila, vide " KNowLEtiGE " for October, 1911, page 406. The asci and spores mount nicely in glycerine jelly, or they may be stained and mounted in glycerine. The figure was drawn from a specimen treated in this w^ay ; the parapliyses (a) XISO and the separate spores (b) X310. , „ '^ Jas. Burton. THE PYGIDIUM OF A FLEA, as mounted by Topping, was formerly sold as a test object, but although in consequence of the improvements in objectives it is no longer regarded as such, it is still an object of great interest to the microscopist on account of its intricate structure, and it has also a claim for consideration inasmuch as it represents a class of organs which are comparatively rare in the insect world. .A. pygidium, properly so called, is the terminal segment of an insect's abdomen, whether or not it bears the peculiar structure usually known by that name. " The pygidium of a flea " as commonly understood, is a paired organ, the two halves of which are in close proximity, enclosed in the same band of chitine and separated only by a narrow ridge of short spiny hairs ; the length of the ridge in the specimen before me is one-seven hundred and fiftieth of an inch, whilst the breadth of the entire organ, including the ridge is one four- hundred and eightieth of an inch. The anterior margin of the band is smooth in outline, but the opposite side terminates in two processes each of which carries a long stifl' spine and is surrounded by numerous hairs of shorter growth. The general surface of each lobe of the pygidium of a flea is studded with minute papillae, short and bulbous at the base, but tipped with a sharp apical spine, and amongst these are placed a number of curious circular depressions, or areolae, the two-thousandth of an inch in diameter, bordered by a ring of chitine from the inner margin of which seven to ten triMicated wedge-shaped plates, about one-<|uarter the diameter of the disc, r.adiate towards the centre, somewhat like the spaces between the spokes of a cart wheel. From the bottom of each depression a long delicate filamentous hair arises from a conical base and passes through the central opening of the areola. The number of areolae in the pygidium varies according to the species of flea — in that of a cat it is twenty- eight, but in lh.it of an abnormally large specimen of doubtful origin in the cabinet of the Ouekett Microscopical Club there are no less than sixty-four, together with a pair of remarkable appendages extending from either side of the anterior portion of the pygidium, which have not been noticed elsewhere. As regards the function of this organ there has been much speculation. All observers agree that it is a sense organ, but of what sense has been a matter of dispute, though the balance of evidence is certainly in favour of its being an organ of hearing. Those who have watched a flea when feeding will have noticed that whilst the head is so much depressed as to preclude observation of its surroundings by the eyes, the abdomen is so elevated as to make the pygidium the highest portion of the body, in which position it would undoubtedly be best situated for perceiving the sound of approaching danger. The Lace-Wing fly, Clirysopa perla, has a similar organ on either side of the last segment of the body, the use of w^hich is also problematical ; the following observation, however, tends to support the idea that the function of the pygidium is auditory. Some years ago a friend in Natal informed me that he had frequently noticed that when a Cicada was singing, it was attended by a number of Lace-Wing flies which were apparently attracted by the music, and from their movements appeared greatly to appreciate it. Many futile attempts were made to capture some of them, but as soon as my friend's approach was perceived the Cicada ceased its song and the audience took flight. .-\t length, having one day noted their exact position on a tree trunk, he approached stealthily from behind, and by suddenly clapping his hands upon the place, succeeded in securing ten of the flies in question, which were subsequently identified as Xotoclirysa ^igantca. The method of capture did not conduce to the specimens being in very good condition, and being very dry when they reached England it was not possible to dissect them with hope of success, but enough was seen to show that each of these flies had a large and prominent pygidium on each side of the last segment of the abdomen, each of which bore not less than forty areolae w-ith a long sensitive filament upstanding from the centre, although the radiating plates appeared to be absent. i; T I THE FINE ADJUST- MENT.— Provision for the focussing movements of a microscope is made by means of slides, consisting of fixed and moveable parts accurately fitted together, one of them carrying the tube. The two parts are either dove-tailed one into the other, or made up of a sleeve fitted over a fixed prismatic bar, usually of triangular section. .A micro- meter screw is used to convey movement directly to the slide bearing the tube, or indirectly through a lover or some other mechanical arrangement for reducing FiGUKli 177. Prismatic Bar Fine Adjustment, Aprii., 191: KNOWLEDGE. 155 the rate of motion. The prismatic bar is a most secure and accur- ate guide, and when it is used the. action of the micrometer screw is generally direct, and raises or lowers the sleeve which carries both the arm and tube •f the microscope. Dove-tailed slides are usually placed immed- iitely behind the coarse adjustment and carry IT and the tube FlGURK 179. Lever Fine .Adjustment. Figure 17S. .Ariston Fine .Adjustment. only, with the advantage that the arm may be lengthened to give greater stage -room without adding to the weight borne by the fine adjustment. A direct-acting micrometer screw i.~ under these conditions inconvenient. and some intermediate mechanism i> usual, generally a lever, but a few maimers use a cam or some adaptn- tion of the principle of a wedge. There are many different varieties of these broad types, and the methods by which the screw or lever, and so on, are utilised, are more or less special to individual makers. The six examples given are selected as showing a fairly wide range. The Direct-acting Micrometer Screw or Prism.-^- Tic B.AR Fixe Adjustment. Figure 177 shows the form adopted by Zeiss. The arm (A) and tube of the microscope are carried on a sleeve (B) which slides upon a vertical tri- angular bar (C). A nut (E) is screwed on to the top of (C) and a spring presses against it and against (Hi. The hardened steel point of the micrometer screw bears on the similarly hardened centre of (HI and works through (Fl which is screwed to the sleeve. When the micrometer screw is turned downwards the tube travels upwards and the spring is compressed. The latter in its turn causes the downward motion as the screw is turned up. This then is a safety fine adjustment, as the objective cannot be screwed by it down on to the cover glass. Most prismatic bar fine adjustments :ire liable to damage if the microscope is lifted by the moveable sleeve, but in this case the danger to the micrometer screw is minimised by fi.xing it to the tube carrier. If the microscope is lifted by the latter the screw is lifted too, while the lower part of the instrument drops until stopped by the counter-nut screw on top of the prismatic bar. The .\riston Fine Adjustment. — The fineness of motion imparted by a direct-acting micrometer screw obviously depends on its pitch, which is generally about one-fiftieth of an inch ( -5 mm. I. and one rotation of the milled heads raises or lowers the microscope tube through that distance. This is not a ver\- slow motion, though adequate for most purposes, and several methods have been adopted to make the movement slower. It is uot advisable to use much finer screws, as they are very liable to damage. Messrs. Swift reduce the speed to one-fifth by interposing two levers, while retaining the general character- istics of the prismatic bar type as shown in the Ariston fine adjustment, (See Figure 17K.) This and most other prismatic bar fine adjustments differ from that of Zeiss in that the pressure of the spring raises the microscope tube, while the action of the screw presses it downwards ; that is, they are not generally of a safety type. On the other hand, the .\riston has the great advantage over most in that the moveable sleeve carrying the limb has a protecting cover screwed over it, by which the microscope may be lifted without damage to the mechanism. The Spencer Lens Company give similar pro- tection by fitting a small guard below the limb. Lever Fine Adjustment. — Figure 179 shows a simple but very efficient way of using the lever in fine adjustments, a method that, with variations, in detail is very largely employed on English and .American stands. It has the follow- ing points of interest. By placing the ful- crum of the lever in suitable positions, any desired ratio can be got between the upward motion of the end of the lever carrying the tube and the downward move- aent of the other end caused by the screw. A very fine motion can consequently be obtained from an ordinary micrometer screw. For instance, Watson and Beck provide a movement of one three-hundredth of an inch with a screw of one-sixtieth of an inch pitch. In the form adopted by Baker the screw is of one-seventieth of an inch pitch and the arms of the lever are as three is to one, so that one rota- tion of the milled head raises the tube one two-hundred and tenth of an inch. It is a safety adjustment, as the downward motion is caused by the weight of the tube and the spring, which also keeps the lever always up to its work against the screw. The bearing points and surfaces are, as in all the adjustments, of hardened steel. -And the limb can be used as a handle without any danger to the mechanism. Figure ISO. Baker's New Lever Fine .Adjustment. ISfi KNOWIJIH-,!-. Al'Kil., 1912. Baker's Nkw Lever Fink Adjustment. — Figure 180 is from a drawiiiK of Hakcr's new lever fine adjnstinciit. aiul is n'ven as an example of the met hods employed for ntlli/iii»; a leviT when the milled heads are placed at the sides. Beck's and the Spencer Lens Company use other forms of levers for the same purpose. .At (.A) are the milled heads; (he thread of the micrometer screw (H) is liftyto the inch. Motion is conveyed by a curved lever (C), whose ratio is one to four, to a narrow wheel (D) intended to elimin- ate friction as nuich as possible. The lever is curved where it touches (D) in such a way as to ensure that the latter carrying the tube is raised an equal amount for each rotation of the milled heads. A spring (F) on the guide pillar (E) keeps the wheel down to its work and causes the downward motion. Each revolution of the milled heads corresponds tu a movement of -125 millimetres oi one two-hundredth of an inch. All slides in this and the last adjustmeni are sprung and screwed. The position of the milled head> found in this fine adjustment is ver\ much in favour now, and adoptetl by many makers, but it must not be supposed that that indicates a similarity in the working parts enclosed in the limb. That of Zeiss, for instance, is actuated by a micrometer screw (see Figure 181). Bergek's Micrometer Screw Fi.NE Adjustment. — (Figure 181). The milled heads actuate a worm which in its turn rotates a cogwheel attached to the micrometer screw. The latter works in a socket firmly fixed to the sliding bar, so that if the milled head is turned to the left the tube will be raised. When turned to the right the socket is brought downwards on to the screw by the spring and tube weight only and disengages from the screw- should the objective touch the cover glass. The guiding cogwheel to the left moves up or down as the milled heads are turned until it reaches the casing and so acts as a stop to the maximum and minimum movement of the adjustment. One rotation of the milled ht^ads gives a movement of one twohundred-and- fiftieth of an inch or 0- 1 millimetrc•^. Leitz' New Fine Adjustment (Figure 182) is illustrated as an example of one of the fine adjust- ments in which mechanical arrange- ments other than a screw and lever are employed. The lateral milled heads convey motion to a wheel td) by worm gearing. This wheel carries a heart-shaped eccentric cam (f),aiid on this a steel roller is pressed by the weight of the tube assisted by a spring. .As the cam is turned the roller which revolves upon it is lifted upwards carrying the microscope tube with it, or falls by the weight of the latter and the spring. I'lGl'KE ISl. Berger Micrometer Screw Fine .Adjustment 1-Tguke 182. Leitz' New F"'ine .Adjustment. One revolution of the milled head corresponds to a rise or fall of • 1 millimetre (jtn-inch). Examination of the figure will show that instead of a limit to the movement of the milled heads in both directions, as there is with most fine adjustments, the motion is continuous and a further rotation when the tube is raised or lowered by the cam to its greatest extent instantly reverses the motion. The rise and fall due to the rotation of the cam is three millimetres, so that reversal need very seldom occur. Continuous fine adjustments have the advantage that there is no fear of damage due to the arrival of the movement at its upper or lower limit. But the uncertainty as to whether one is focussing up or down is occasionally a drawback, although a glance at the indicator on the sliding bar and limb serves to show the direction of movement, and as the milled heads can be made to work in the same direction as those of Ihe coarse adjustment at any time the difficulty should seldom arise. The milled heads of any fine adjustment can be had graduated in fifty or one hundred divisions, so that the amount of motion given can be determined when required for purposes of measurement. The testing and selection of a fine adjustment is almost as im- portant as the choice of objectives ; for unless the former is satisfactory it is impossible to use the lenses to their best advantage. The work put into modern microscopes is so uniform in quality that the efliciency of any adjustment fitted by a maker of repute may be relied on. One may be slower in motion than another, but it is not fair to say on that account that it is better, unless the use to which the instrument will be put is known. .A movement of one-fiftieth or one-sixtieth of an inch for each rotation of the milled heads is quite adequate for low and medium powers, and in many cases preferable to a slower one ;is more durable and tending to save time in laboratory work. But for high powers and particularly lor photo-micrography it is ditficult to ;:< t too slow a fine adjustment. I ' advantages of a fast and motion are often combined the same instrument by fixing a spindle of small diameter to the centre of the milled head. It may be rapidly rotated when a faster movement is desired. Secondary levers are sometimes added to reduce the speed of a fast type, as in the .Ariston. or the M.ales.\\"atson. which is provided with two milled heads. Becks use two concenlric micro- niler screws of difterent pitch to actuate their lever fine nljustment, giving movements of one-si.xtieth and one-three- hundredth of an inch respectively. Safety types have a distinct advantage over other Ai'Kll., 191. KNOWLEDGE. 157 adjustments, and the liability to damage of the adjustment itself must not be overlooked. The position of the milled heads should be such as to permit of the hand or arm resting on the table while using them. Above all. particular attention must be paid to the sweetness and ste.idiiu-ss with which the adjustment works, and the following faults should on no account occur in use : Backlash, loss of time or sag on reversal of movement, lateral movement of the object across the field. And there should be no tendency for an object to go out of focus if the table receives a slight jar. These are all guarded against by well-fitting slides and the provision of suitable springs to keep the mechanism up to its work. Good working properties are ensured in different ways by different makers and it will be well in this connection to compare the advantages claimed for sprung and ground-in slides. If the adjustment slides of various microscopes are examined, some will be found to be " sprung " or slotted and held up true with screws, while others are not. Reliance, in the second case, is placed on the fit produced by grinding one part into the other. In support of sprung slides it is urged that when play through wear becomes noticeable, it may be taken up by tightening the screws and without returning the microscope to the maker. But against this advantage must be placed the difficulty of so exactly adjusting the screws that the slide works truly throughout its entire length and not only at a greater or less number of points. The alternative method of grinding one bearing part accurately into the other is now generally acknowledged as the better, but it involves the expenditure of much time in making a good fit and the use of very good materials if it is to wear well. Play is generally less than that in sprung slides, but when it does occur the microscope must be sent to the maker for readjustment. A good fitting should last for many years without any undue evidence of shake. ,, , ,, i. c- i- i /- H. Li.oYD Hind, B.Sc, P.I.C. QUEKETT MICROSCOPICAL CL LB. —February 27th, Annual General Meeting. The Presidential Address was delivered by Professor E. A. Minchin, M.A., F.R.S., who took as his subject " Some speculations with regard to the simplest forms of life and their origin on the earth." The most distinctive property of living things is the power of metabolism. All living bodies consist essentially of protoplasm which is composed mainly of proteins. In all li\ing organisms certain granules of a peculiar substance, chromatin, are found in the cytoplasm. Chromatin consists of protein substances more complex even than those found in the cytoplasm. The simplest forms of life appear to be little or nothing more than minute grains of chromatin. There are two views with regard to the nature and composition of the body in the simplest and most primitive forms of life; the first, the chromatinic theory, assumes that the primitive living substance is chromatin, and that the earliest forms of life were minute particles of chromatin ; the second, the cytoplasmic theory, regards the cytoplasm as the primitive living substance, and supposes that the earliest living things were composed of cytoplasm alone. .As an example of theories which maintiiin that life originated on the earth, that of Sir Ray Lankester was mentioned, according to which it is supposed that life originated at the time when the earth had cooled down suflficiently to have a firm crust upon which water was condensed. The chemical and electrical disturbances which undoubtedly then occurred might conceivably have brought about synthesis of organic compounds in a manner and to an extent which does not occur at the present day. This synthesis might conceivably have culminated in proteins and the pro- duction of the earliest protoplasm, and the earliest living things would probably have been relatively large masses of cytoplasm, in which chromatin was a product formed later. As an example of theories which assume that life was in some way brought to the earth when it was cooled sufficiently for life to exist upon it, that of Professor .Arrhenius was taken. He regards life as eternal and cpeval with our universe, and believes that it exists throughout the universe in the form of minute particles (,? chromatin), which are transported through infinite space by radiation pressure. A particle in size of the order of 0-16m would be required, and it is probable that some of the almost invisible microbes of certain diseases (Chlamydozoa) are of smaller dimensions than this value. It is not possible to decide in favour of the one theory or the other in the present state of our knowledge of living things. ORNITHOLOGY. By Hugh Boyd Watt, M.B.O.U. CASUAL BIRDS IN THE BRITISH ISLES. — Birds as a class are great vagrants, and the avi-fauna of the British Isles is steadily being augmented by new species, such as those which have been reported in recent numbers of " Kn'owlkdge." These, with other very rare occasional and accidental visitors, may be called natural "' casuals." It is difficult to draw a line between rarity in the occurrence of a species and casualness, for it is not adequate to say that, in the last-named, what is called " chance " must be present. Under quite natural conditions it seems to be the same factor of chance which shapes the destiny of those bird-waifs, many different kinds of which have now occurred in the British Isles, often blown or strayed out of their course on migration. In illustration of the large casual or occasional element amongst British birds it may be said that, of the four hundred and fifty species or thereabouts now admitted to our list, no fewer than two hundred and seven are classed as occasional visitors and not breeding. These cannot all or always be correctly called casuals, but a large number of them have the most slender claims to be called British. Of the two hundred and seven, some one hundred and five have not occurred more than six times each, and some of these only once or twice. .\ much less questionable casual element is composed of foreign species, mostly introduced by man, and taking to freedom for a time or tentatively. This excludes such birds as the Pheasant and Red-legged Partridge which have been long naturalized in this country. .Accidental or temporary intro- ductions are a different thing, and the following incident is suggestive of what may have often happened, although perhaps not in quite the same way. When the steamer ■' Minnehaha" was wrecked on the Scilly Isles, in April, I'JIO, a number of .American birds on board, consigned from New York to the Zoological Gardens, London, were liberated to give them a chance to save themselves. -Amongst them were Parrotlets, Ground Doves, Inca Doves, Crested Ouails, Red-winged Starlings and Purple and Bronze Grackles,which,if finding their way ashore, would make a strong casual element for, at any rate, a brief time in the avi-fauna of the place. Ships, unwittingly, and sailors and travellers purposely, often bring foreign animals of different kinds to our country, birds probably most abundantly. When the steamer "Mauretania" was about five hundred miles out from New York, eastward bound, on 15th June, 1911, a Curlew came on board and remained for three days, leaving only when the Irish Coast was sighted (Coward's " .Migration of Birds." 1912. Page 122). No doubt it made the land and thus joined the bird population of the British Isles. Even native species are sometimes so conveyed, as the case of the Peregrine Falcon given in the last issue of " Knovvlkdge " (page 116) shows. The spire of Shoreditch Church was the home of a solitary Falcon for many years, and Kites which were liberated from the Zoological Gardens, London used to return there to feed. .A Black Kite, which had escaped from its cage there, would fly over the heads of visitors quite unconcerned, in the hope of having tit-bits thrown to it. The sight of this raptorial bird on the wing caused so great a panic amongst the smaller birds in the aviaries that after a week's freedom it was induced to return to its cage. A still larger bird of prey which has accidentally been at large in London is the Vulture. In August, 1898, five Jamaican Vultures were free in the Borough, haunt- ing the house-tops and steeples for some days; and in the same month one, which was consigned to the Hungarian Exhibition, Earl's Court, escaped from a broken crate and took to such freedom as the neighbouring roofs afforded. 158 KNO\VLi:nGE. Ai'Hii . I'M 2. When It i> Miiiiiiil)creil tli.it mnamcntal Water- I'owl of many kiiuls are kept in partial fni'cloni in a largo number of places botli pnblic anil private, .and that numbers of foreign species arc amongst them, it is only too sure that escapes take place and form casnal and irrcKular and unjnstifiable additions to "British" birds. Recent examples of this kind are the American Wigeon. Uaikal Teal. Knddy Shelkliick, Snow Goose and probably the American Bittern, and the list could be continued indefinitely. Some of these birds also occur truly wild. On the ponds in St. James' Park. London, some forty different kinds of birds are kept, and at places like Woburn Bark, Bedfordshire, many species of non- British seesc. ducks, and other water-fowl breed year after year successfully. Some other foreign birds are at liberty at Woburn all the year round, such as Red-Crested and Dominican Cardinals, which nest in the gardens and have young. Orange Weavers have made a nest there, but no eggs were laid. There are also numbers of the Australian Crested Pigeon (Ocypluips lopliotes) and the Bronze-Winged Pigeon (Pliaps chalcoptcra) in the Woburn Woods at large. Australian Doves, liberated from the Zoological Gardens, bred in the trees in the grounds and in the park, and some wandered olT. There is a definite record of the escape from Woburn of a South American Lapwing (VaneUns cayen- nensis), which was shot some distance away as an unknown bird. Flamingos have occurred very rarely wild in this country, but it is known that birds of this kind sometimes get away from Woburn and, no doubt, from other collections also. One, for instance, seen feeding on the Glamorgan- shire coast, in December, 1908, was supposed to be a bird which had made its escape from Cardiff Castle three weeks previously. A Flamingo recently flew, assisted by a gale of wind, from the Zoological Gardens, London, into the open park and going out of sight over the tree-tops was given up for lost, but circling round in the air it returned to the park and was secured. An odd "Zoo" story is that of a young Penguin which about a year ago escaped and was discovered walking along Baker Street (so the newspapers stated at the time). Later on the same bird was missing again and was believed to be in hiding in Regent's Park and living on the fish in the lake. At present there is a pair of red-breasted Cockatoos at liberty from the "Zoo" and there is no intention of recapturing them, so long as they do no mischief. They take long flights in the Gardens and at dusk fly off and roost in the elms in Regent's Park. It is not unlikely that they may nest in the spring in these high trees and thus be genuine casuals, as this hardy bird can well take care of itself. In 1908, one was shot which had been robbing a poultry-yard in Glamorganshire. It was mistaken for a hawk, being quite wild, and the place from which it had escaped could not be ascertained, nor the time during which it had maintained itself free. It has sometimes been suggested that Parakeets might be liberated in English parks as ornamental birds, but this would be dangerous as, if becoming abundant, they might do damage to growing crops and to some of our native birds. At present Ring-necked Indian Parakeets, belonging to Mr. W. Jamrach, are at liberty at Stoke Newington. and come down to feed in the poultry-yard. They live day and night in the open and if they survive, it is proposed to liberate others there. Pekin Robins iLiothrix h'ltcus) have been tried in St. James' Park. London, and probably elsewhere, but. so far as I know, without success. .\merican Robins iTunlus tnifiratoriiis) were turned out near Guildford in 1908 or 1909, and freely nested there, increasing in numbers considerably. To such introductions as these ornithological purists are strongly opposed, particularly if success is attained. The case of the Little Owl iAthenc noctiia), which has now established itself in many places in England, is looked upon with repro- bation, and that of the Willow Grouse \Ln<>opiis albiis) is considered quite as reprehensible in the areas where it has been introduced. The .American Wild Tiukey has been tried at Luss and Inveraray and probably elsewhere, but has not made good its footing or spread. Purple Gallinules [Porphyriola allciti) have been shot in various parts of England, but this is an Australian bird often kept with ornamental water- fowl, and being a great climber it can get over high wire-netting and thus escape. The .Mbatros is probably the most conspicuous casual recorded in our avi-fauna. The Bl;ick-browed Albatros {Dioiiicdca mclaiiopliyrs) occasionally finds its way into ICuropean waters, and one was taken alive near Linton. Cambridgeshire, in 1897. 1 believe that instances are known of Albatroses having been brought over the line on board ships, and allowed to fly olTon the northern side. They would be likely to take a northern course, and this may account for the occurrence of the species in Europe (J. F. Green, " (Jcean Birds," page 4). The one or two old records in England of the Tropic-bird (Pliacton I may be accounted for by conveyance by ships, or may have been caused by violent storms. There is a remarkable instance of a Bird-of- Paradise (a hen Rifle-bird) living in freedom fortenweeksin Sussex. Hensofthis species were imported from New Guinea into this country for the first time in 1908, and one managed to escape when being transferred from its travelling cage to the large aviary for which it was destined near Groombridge. It was lost sight of from 7th September till 19th November, and was supposed to have completely disappeared, when, on the last-named date, it stunned itself by dashing against the window of a house about two miles away from the place where it had escaped. It soon recovered and was found to be in good health, and was committed to the aviary for which it had been intended. It is a demonstration of the hardiness of such birds, and probably a unitiue casual case in our country. — Read before the Hanipstcad Scientific Society, February Sth. 1912. MENDELIAN EXPERIMENTS.— At the scientific meet- ing of the Zoological Society. London, on f)th February, two papers on Mendelism were read. The first, by Mrs. Rose Haig Thomas, described a breeding experiment which she had carried out with pheasants in order to confirm one previously made in which a cock pheasant had transmitted the female plumage of his species to his female offspring of the F 2 generation. This second experiment was conducted with the F'ormosan pheasant (P. forinosanus) and the Japanese pheasant (P. versicolor), and produced a similar result. The second paper, by Mr. J. T. Cunningham, dealt with the characters of a number of individuals of the V 2 generation, reared from a cross between a Silky hen and a Bankiva cock, bred in the Society's gardens by Mr. D. Seth-Smith. The author described the various characters in detail, and remarked that the most important results obtained were imperfect segregation in the F 2 generation in at least two of the characters — viz., absence of pigmentation in the plumage, and also in the skins and tissues. PHOTOGRAPHY. i;y Edgar Senior. INFLUENCE OF ULTRA-VIOLET RAYS.— In "Notes" for last month we showed how the suggestion put forward by Fox Talbot in 1844 had been practically realized in the taking of the portrait which formed the illustration. Not only, then, will these dark rays act to such an extent upon the seilsitive plate as to enable us to produce images by their aid, but they may be the means of causing trouble in quite an opposite direction : for if the sensitiveness of the plate depends upon the absorption of these rays by the silver salt, and the body upon which the light falls either partially or entirely absorbs them itself, it is obvious that little or no action would take place upon the photographic plate. To test this it is only necessary to write upon white paper with a solution of the same substance Ujuininc sulphate) that was used to make the dark region of the spectrum visible, and then to take a photograph, using the same screen that was previously employed to cut oft" all visible light, when upon development a strong image of the writing, " which was invisible to the eye on the paper," will be produced, owing to the sulphate of quinine having absorbed the ultra-violet rays, with the result that the writing is rendered as black on a white ground in the print from such a negative. We April, 1912. KNOWLEDGE. 159 thus see that the absence of these rays, owing to the action of the substance itself upon them, might be the cause of serious trouble in photographing when the silver salt in use was mainly sensitive to them, or the light particularly rich in such. It is thus evident that the photographic rendering of certain bodies is influenced by the nature of the plate employed and the kind of light used in illiuninating the object. We will suppose that a wash drawing has to be copied, and that it is illuminated by the light from an enclosed arc, and that the negative is made upon a wet collodion plate. Now the light itself is rich in ultra-violet, and the wet plate very sensitive in this region. The result is that a negative could be taken with a compara- tively short exposure. If for the wash drawing we substitute our white paper with the invisible writing upon it "made with quinine sulphate " ([uite a strong image would be obtained upon the wet plate owing to the substance having absorbed those rays which produce a strong action upon the plate, with the result that the sensitiveness of the silver salt has been apparently destroyed in those parts, and a negative image of the writing which will show as dark upon a more or less white ground in the print, results. Sulphate of ([uinine, however, is not the only body which behaves towaids light in this way. Chinese white is a notable example and in the case of drawings in which this is used and the photographs taken under the conditions enumerated above, the effect is either to produce a black or a very degraded white. Owing to this difficulty other whites have been introduced, but unfortunately bodies are present as well, which may complicate matters by setting up chemical action, that may result in the white assuming a tint which is photographically very non-actinic. That this is the case can be \ery readily understood when we come to consider the pigments with which drawings are made and their close proximity and admixture with the white itself. Then, again, the medium with which the white is ground may exert some influence, and from some experiments made, this appears to be the case, as pure oxide of zinc photographs differently according to the method used in preparing the pigment. If we use other sources of light for the illumination, such as daylight or the open arc, again the results differ, so that the only really satisfactory test as to the photographic value of one of these pigments, is to make negatives under precisely those conditions that obtain in practice. But even then we shall only gain information as to how the white would photograph when used under ideal conditions ; it will not tell us what the result might be were some other substance present in so small a quantity as not to visually alter its colour and yet photographically it might do so to a con- siderable extent. EXPOSURE TABLE FOR APRIL.— The calculations are made with the actinograph for plates of speed 200 H and D, the subject a near one, and lens aperture F16. Day of the Month. Condition of the Light. Time of Day. | 11 a.m. to 1 p.m. 10 and 2 3 p.m. Remarks. .A.pril 1st Bright Dull 10 sec. "25 ., 13 sec. "27 ,, 15 sec. ■3 ,, If the sub- ject be a general open landscape take half the exposures given here. .\pril 15th Bright Dull '09 sec. ■21 ,, 12 sec. ■25 ,, 13 sec. •28 ,, April 30th Bright Dull 08 sec. 19 .. '1 sec. '2 12 sec. ■24 ,. PHYSICS. By .Alfred C. G. Egerto.n, B.Sc. VAPOUR PRESSURE.— When a substance is situated in an enclosed space there is a certain pressure set up within that space, owing to the tendency of the substance to vaporise. At any particular temperature ail equilibrium is set up between the molecules leaving the surface as vapour and those con- densing back on the surface as liquid or solid. .As the temperature rises so the vapour pressure increases. Ice at 0" C has a vapour pressure of 4 ■ 6 millimetres of mercury ; ice at 10° C, about two millimetres; water at 100°, seven hundred and sixty millimetres. When the vapour pressure is the same as the external pressure, then the liquid boils ; thus water boils at 100° when the barometer stands at the normal pressure of seven hundred and sixty millimetres. If the vapour pressure of a solid is greater than that of the external pressure, then the solid wmII vaporise without licjuefying. An example of this is solid carbon dioxide, which has a vapour pressure, at so low a temperature as — 60°,greater than the atmospheric temperature, and goes over into gaseous carbon dioxide without licjuefac- tion. Now gold boils at a temperature about 1000" C, that is to say, its vapour pressm-e is seven hundred and sixty millimetres at its boiling-point. As the gold cools, so its vapour pressure decreases and becomes so small that, at ordinary pressures, the vapour pressure is undetectable. It would be very interesting if the vapour pressure curves of metals could be carried down to very small values ; the shapes of the curves would no doubt show whether the molecules associated as the temperatures decrease and the molecules of the metal become larger and heavier. It is known that in solution in mercury the molecules of most metals are simple atoms. It is difficult to conceive of iron, brass and connuon metals of that sort having a definite vapour pressure at ordinary temperatures and losing weight gradually — the effect is so small as to be undetectable by known means : and it is possible for a crystalline material of homogeneous com- position that the molecules are so closely packed that the vapour pressure is absolutely nil, and no molecules whatever arc able to leave the surface. When the substance is definitely crystallised and when the molecules possess so little kinetic energy that they cannot leave the surface, one would expect the vapour pressure to become zero. The vapour pressure of mercury has been measured at tempera- tures below 0° C and has a very small value (-0008), but the pressure of the solid mercury is so small as to be unmeasur- able. Vapour pressures of less than a hundred-thousandth of a millimetre cannot be measured as yet. The methods of measuring small vapour pressures may be sub-divided into two main classes — dynamic and statical. The former class contains such methods as depend on the passage of some inert gas over the material under investigation and estimation of the amount carried over in a certain time. The second class measures directly the actual pressure set up by the vaporising substance. Some have used a very thin copper vane dividing a vessel into two chambers. Into one chamber the substance is introduced and the two chambers are then evacuated and closed : any difference of pressure is then measured by the deflection of the copper vane, such deflection being detected by causing light falling on the copper vane to interfere with the waves of another beam of light. Another method, employed by Dewar and others, depends on the change in rate of action of a " radio- meter" as the pressure is altered. A radiometer is an instru- ment which consists of a light vane mounted within a fairly high vacuum — heat waves falling on one side of the vane, heat that side and increase the motion of the gas molecules in its neighbourhood and the vane is repelled away from them. Sir William Crookes discovered this action and the experiments led him later to the study of electric discharges in high vacua and the discovery of the cathode rays. Lord Rayleigh devised a sensitive manometer to measure small differences of pressure —by tilting the manometer, the levels of liquid iri the two limbs can be brought so as just to touch two very fine points — the amount of tilt being measured by reflection of a spot of light from a mirror. A method of measuring low pres- sures of great ingenuity has been devised by Pirano. This consists of a specially constructed electric filament lamp of fine tungsten or platinum wire. The resistance of the wire in one such lamp is balanced against that of another. The one lamp is connected to the apparatus containing the substance the vapour pressure of which is required; this raises the pressure of the gas ever so slightly in the one bulb, and hence heat is conveyed away from the wire by the gas faster than from the wire in the other bulb 160 KNOWLl'DGH Ai'KiL. I9i; and tlu- bahincc of rcsislnncc changes according as the ti'Mipcratiiif of llio wire of one of tin- bulbs alters. 'l"hc method appears aceiirate, but is of very limited application. Ne.xt. the MacLeod nange should be mentioned — most low pressure measurements are made by means of such an apparatus: but the values obtained are only reliable under certain eircinnstances. This apparatus consists of a large bulb with a small tube connected to it. Gas in the large bulb can be pushed up into the small tube and measured imder atmospheric pressure — from the change in volume from the large volume of the bulb to the small volume of the tube, the change in pressure from some low value to be found, to atmospheric pressure can be obtained from Boyle's Law " that the volume of a gas varies inversely as the pressure upon it. if the temperature is constant." However, the reliability of Boyle's Law at very low pressures is not absolutely certain, though experiments do tend to show that at low pressures the laws about gases still hold — and, further, the mercury itself has a certain vapour pressure which is entirely unmcasurable and neglected by this instrument. The walls of the tubes also are apt to condense vapours in their pores. Measurements of the pressure within X-ray tubes and electric lamps are made by means of the MacLeod gauge — the gauge gives an idea of the degree of vacuum attained, but is unreliable for absolute measurements of pressure. The subject of vapour pressure is intimately connected with that of smell. The nasal nerves are capable of detecting a very small quantity of a substance — it is possible that one molecnle of a substance, if it gets properly into contact with the sensitive portion of the nasal organ, might affect it perceptibly. The quantity of a gas. such as bromine, which is detectable is very small indeed, and the pressures of vapours detectable by smell are smaller than can be directly measured. The effect is probably of a chemical nature — a loose combina- tion, perhaps, is formed between the molecules of the vapour and the substances of the nasal organ — it is noticeable that the smells of all oxidising substances, when dilute, are practically identical, which seems to show that the effect produced by them on the nasal organ is similar. The sensitiveness of the nasal organs of animals is well established, and it is indeed marvellous to think that sufficient molecules which can be smelt are left behind by a person who has passed a locality perhaps an hour previous to the arrival of his dog ! There is much interesting work to be done in this direction, and I have thought it worth while to draw attention to it in this month's notes. SEISMOLOGY. By Charles Davison, Sc.D., F.G.S. THE ORIGIN OF EARTHQUAKES.— In a lecture on "The elastic-rebound theory of earthquakes" (Univ. of California Publications, Bull, of the Department of Geology, volume VI., pages 413-4441. Professor H. I". Keid discusses a theory of the origin of earthquakes which has long been known, and I believe generally accepted, in this country. The theory is that earthtjuakes are due to the friction caused by the sudden sliding of the rock-masses adjoining a fault-surface, that they are, therefore, merely passing incidents of secondary importance in the growth of faults. Professor Reid bases his account of the theory on the remarkable displacements of the crust along the San Andreas fault which gave rise to the Californian earth<|uake of 1906. He sums up the theory in the following terms: "1. The fracture of the rock, which causes a tectonic earthijuake, is the result of elastic strains, greater than the strength of the rock can withstand, produced by the relative displacements of neigh- bouring portions of the earth's crust. 2. These relative dis- placements are not produced suddenly at the time of the fracture, but attain their maximum amounts gradually during a more or less long period of time. 3. The only mass move- ments that occur at the time of the earthcpiake arc the sudden elastic rebounds of the sides of the fracture towards positions of no elastic strain ; and these movements extend to distances of only a few miles from the fracture. 4. The earthquake vibrations originate in the surface of fracture ; the surface from which they start has at first a very small area, which may (piickly become very large, but at a rate not greater than the velocity of compressional elastic waves in the rock. 5. The energy liberated at the time of an earthquake was, immediately before the rupture, in the form of energy of elastic strain of the rock." ZOOLOGY. By Pkoi-kssor J. Arthur Thomson, M.A. AOUATIC VERTEBRATES OF SAHARA.— It seems strange to speak of the freshw.iter fauna of the great desert, but it is a reality and of very considerable geographical interest. Besides a crocodile {Crocodilus itiloticns) and a turtle, there are eight Amphibians and ten fishes. The interesting point is this, as J. Pellegrin points out. that while the more northern part of Africa has a Palaearctic Mediterranean fauna, the aquatic vertebrates of the Sahara are distinctively Ethiopian. ORIGIN OF GERM-CELLS IN SILK-MOTH.— Another instance of the early segregation of the future germ-cells has been found by Vaney and Conte in the development of the egg of the silk-moth. At an early stage, when the blastoderm has been formed and the germinal disc marked off, two large cells appear between the blastoderm and the yolk which seem to form the future germ-cells. The segregation is not so precocious as in some other insects (the harlequin fly, Cecidomyia, and Chrysomelid beetles), but it is nevertheless a good instance of the early separation of the germ -plasm from any share in body-making. PEARL MAKING. — A. Rubbel has made a very careful study of pearl formation in the freshwater nms!n;\. Margaritana iiiargaritifcra. and is against the theory- that they are the sepulchres of parasites. He finds that they arise around particles of a yellow substance, which resembles periostracum. They originate in closed, single-layered sacs of epithelium, which are constricted off from the external epithelium of the mantle, and. like the mantle, are able to secrete all the layers of the shell. The pearls grow by the deposition of layer after layer on their surface. The coalescence of several pearl sacs leads to the formation of curious pearl conglomerates. What are called shell pearls are formed, to begin with, in the mantle, and become secondarily attached to the shell. They are to be distinguished from shell concretions, which are due to intruded foreign bodies and show no concentric layering. Besides rejecting the parasitic theory of pearl formation, Rubbel calls attention to an overlooked fourth layer in the shell. It is a clear intermediate layer, dividing the nacreous layer into an outer and an inner stratum ; it is particularly clear at the muscle insertions, but it occurs in other parts of the shell and in the pearls, THE TURTLE'S EGG-LAVING.— S. O. Mast gives an interesting account of the behaviour of the Loggerhead Turtle in depositing its eggs. He watched the process on Logger- head Key, Florida, in the month of July. The animal came straight out of the water about sgven o'clock in the evening and proceeded directly up the beach for fifty or sixty feet. There seemed to be no selection of a place for the nest. By moving the posterior part of the body from side to side, and by throwing out the sand sideways and forward alternately with the hind flippers, she dug a trench four feet long and nearly ten inches deep in the middle. In this trench in a very complicated way she made a cylindrical hole nearly as deep as the length of the hind flippers. Into this hole the eggs were dropped — perhaps a hundred altogether. Noise and gentle touching did not cause any interruption. .After laying the eggs the turtle covered them up. filling the trench as well as the hole. " This completed, she returned to the sea and entered only a few feet from the spot where she came out. On the way down the beach I stood on her back and she carried me (165 lbs.) apparently with but little effort." The turtle under observation was out of water forty-two minutes, spending three in reaching the nesting- place, four in making the trench, eight in digging the hole, twelve in laying the eggs, and fifteen in filling up, smoothing over and getting back to sea. The rate of locomotion on land is about half a mile an hour. April. 1912. KNOWLMDGi;. 161 BORING BIVALVES. — For a long time there have been two theories in the field with regard to the method by which Phol.ids and other bivalves bore through rocks. .-Vccording to one theory the boring is at least partly due to an acid secretion; according to another theory it is mainly accom- plished by mechanical means. B. Lindsay has studied Xirpluica iPholas) crispata and Saxicai'a nifiosa, at St. .•\ndrcws, and comes to the conclusion that the boring is in these cases entirely mechanical. The Zirphnca works in two wa>s — sucking and scraping ; " it might be described as a combination of a nutmcg-gratcr and a vacuum-cleaner." The foot is extruded : a wide gap appears between the toot and the mantle ; the mantle becomes fully extruded, and then rotatory movements begin. The shells consist of aragonite — h.itder than the usual calcite — and this must help in the boring. dischargh: of spermato-?oa in fresh- water MfSSEL. — Oswald H. Latter gives an account of this process as he saw it in May of last year. A specimen of L'liio pictoriiin emitted from the exhalant aperture a fine double stream of milky substance, which rose nearly to the surface of the water and then fell as a diffused cloud. The whole of the wafer in the aquarium became cloudy and the emission continued for some hours. It appeared to be under control, for a slight shaking of the floor was followed by a cessation of the streams though the ordinary exhalant current of water appeared to continue without interruption. The liberated material consisted of myriads of sperm-balls, revolving and swimming like Volvox. and finally breaking up into the component spermatozoa which exhibited astonishing activity, sustained below a cover-slip for seven hours after liberation. THEORY OF GALLS.— Jules Cotte makes some very interesting remarks on the origin of " zocicecidia"; that is to say. galls made by animals. He points out that there is often a striking structural resemblance between the animal-made gall and the plant-made gall ; that animals far apart from one another seem able to make very similar galls ; that the same animal produces very diverse galls : that an animal which causes galls at one place or at one season may be inoffensive at another : that there is sometimes a puzzling disproportion between the dimensions of the gall and the number of alleged producers: that some galls continue to grow after the parasites have disappeared, and that others are formed before the ovum of the parasite has been hatched. All this leads up to the theory that many so-called animal-made galls are due to moulds or bacteria or the like introduced by the animal. The insect or mite is a carrier of a vegetable infection, and in many cases the zoocecidia are demonstrably associated with fungoid growth. Cotte does not deny that there may be true zoocecidia, but he thinks that many are more accurately described as myco-zoiicecidia or phy to- zoocecidia. SOL.AR l)ISTrRl!.\XCES DUKIXC I- I-.T-Rr ARV, 1912. Hv FRANK c. di:xxi:tt. Fkbruarv has yielded a much better proportion of dates when telescopic scrutiny of the Sun was possible than either of the two previous months. Only on three days (8th, lith, and 16th) did he escape observation. The central meridian at noon on February 1st was 108' 45'. No spots were obser\-ed during the month, though there were some faculic disturbances as shown on the diagram. On February 2nd and 3rd. a group within the eastern limb occupied the area between longitudes 27° and J 7°, and south latitude y and 6°. On the 17th and ISth a facula within the eastern limb was situated at longitude 180', south latitude 9 . On the 24th some faculae near the western limb must have been about longitude 245^, and near to the ecjuator. but were not measured. Also on the 24th and 25th a faculic disturbance was noted within the eastern limb, a little over 10° south latitude and near longitude 88". On the 27th a small facula was situated at longitude 205°. north latitude 20°. and so near the north-western limb. A larger and paler disturbance, containing a dull patch near its eastern end. was also approaching the western limb, and situated between longitudes 90° and 200. south latitude 6" to S". On the 29th a facula. doubtless that seen on the 17th and 18th, was approaching the western limb in south latitude. Mr. E. W. Maunder, writing at the desire of the Astronomer- Royal, kindly tells us that "two small faint spots in the middle of a little group of faculae were photographed at the Cape Observatory on December 18th last. One of the spots remained to the next day, when it was smaller but darker. It was photographed at Greenwich on December 19th. The positions as measured were : — Dec. 18.— Long. 295° -3 .. 18.— „ 293° -5 ., 19.— „ 295° -1 Lat. N. 22 -7 .. N. 24-2 .. N. 23°-.r This district would cross the Sun's central meridian only a little after midnight on December 21-22. It almost appears as if it were the starting of a new cycle of solar activity, and also interesting as occurring in the northern hemisphere as was foreshadowed. Our chart is constructed from the combined observations of Messrs. John McHarg, A. A. Buss, E. E. Peacock, W. H. Izzard, and the writer. DAY OF FEBRLARV. ii_ fcnM 0 10 a JO 40 50 (jo > '1/ w 10 iiiiii.— Hy Ni:vil. Gokhon Mi'NKo, M.D. 705 pa^os. 421 illustrations. 9-iii.X6|-in. (Willi.iin Hryce. Price 24/- net.) TIk" profaci- of this book is dated January 5tli, lyO.S, but a foot-note- ti'Us lis that the great number of the copies were iuiniedialely destroyed by fire. Those who are interested in 1-Jiropean ;inlii|iiitii,'s will rejoice that the work has been reprinti'd, for the seven hundred pages are crowded with notes and pictures, illustrating Paleolithic and Neolithic rem.ains as well as intermediate pottery ; Bronze vestiges are also dealt with, while four chapters are devoted to Vamato remains. The last chapter deals with the prehistoric races themselves .ind contains also some reproductions of good photographs of the Ainu. To the general reader, no doubt, the discussion on diet, dress and social relations will prove attractive. Dr. Munro holds very definite opinions, for instance, on the origin of clothing and he says that notwithstanding the confusion which has .arisen regarding its primary function there can be no (|uestion that the habit of dress originated in personal decora- tion. .'\s a means to an end — namely, sexual selection — it is almost impossible to exaggerate the importance of personal embellishment in modifying, sustaining, or emphasising various characters of the race. .All the same, in his following sentence he seems to recognise the adoption of clothing for reasons of coquetry, for he alludes to the alluring motive of modern ball - room costume. Dr. Munro's remarks on face-painting may also be mentioned. Red appeared to be the favourite colour, but two black spots on the forehead were affected by the court nobility of both sexes till a few decades ago, not for embellishment, as were the patches of Europe, but as a sign of rank. The painted patterns also, judging from primitive images, show a likeness to those which were originally tattooed. We congratulate Dr. Munro on having produced a most useful and attractive book. W. M. \V. PSVCHOLOGV. A Text-Book of Experiinoital Psycliology. with Labora- tory Exercises. — By Charles S. Mvkrs. 2 vols. Second Edition. Part I : Text-book. 344 pages. 1 plate and 24 figures and diagrams. Part II : Laboratory Exercises. 107 pages. 42 figures and diagrams. Sj-in. X5J-iu. (Cambridge University Press. Price 10/6 net.) The first edition of Dr. Myers's work was published some three years ago and at once took a place in the first rank of text-books of this class. Of it a critic, writing in one of the leading .American journals, said: "It is a qui^stion whether any single book contains as much information as does Myers's text-book." Both in range and quality, both in method of arrangement and in presentation, the work was admirable. The new and enlarged edition brings the treatment up to date and is worthy of the heartiest commendation. Although it is not primarily meant for the general reader, although the dis- cussion is too thorough to afford light and easj' reading, yet all those who appreciate the genuine scientific spirit, all those who feel the charm of living touch with contemporary investi- g.ilion. will luiii 111 Dr. Myii>^ woik with profit and pleasure. There may, however, arise some sense of disappointment that so large a proportion of the space at his comiiiand is devoted by the author to sensation and to what may be termed the lower ;iiid more elementary factors in experience. But this is inevitable in any attempt to apply in psychology the touch stone of experiment. Methods of dealing with the more complex mental products and processes have only recently been devised and are on their trial. Dr. Myers has .added in this edition a new chapter on Thought and Volition, in which the question of imageless thought is briefly considered. We trust that arrangements have been made by which Di. Myers will be enabled to bring his admirable work up to date at comparatively short intervals. If this be done it will continue to retain the position which it has won. C. LI. M. ZOOLOGY. Social Life in the Insect World. — By J. H. F.^BRE. Translated by Bernard Miall. 327 pages. 14 illustrations. 9-in.X6-in. (T. Fisher Unwin. Price 10 6 net.) This series of observations — by that well-known French entomologist, described by Darwin as an " inimit.able observer " — makes most fascinating reading. By careful and patient watching, renewed season after season, he endeavours to throw light on many interesting points — as. for example, the wonderful power possessed by the female Emperor moth of attracting the males from long distances. Several chapters are devoted to the very peculiar habits of the Praying Mantis, while various other insects are similarly dealt with. The book is written in an exceedingly attractive style, and the photos by which it is illustrated complete an .altogether delight- ful volume. .\. .\. A Junior Coarse of Zoology. — Bv the Late .\. Mll.NES Marshai.i,. M.D., D.Sc, M.A.,' F.R.S. 515 pages. 04 illustrations. 72-in.X 5i-in. (Smith, Elder & Co. Price 10 6 net.l No one who in the old days used " Marshall and Hurst " to their advantage can fail to welcome the appearance of the seventh edition, which Professor Gamble has prepared for the press. .\\. the same time it may not be amiss for one who has had many ^-ears' practical experience of the book to point out its greatest failing. This is really nothing to do with the subject matter but with the method in which the very useful figures are labelled. If only the actual names of the parts had been written on the diagrams instead of various letters for the meaning of which the student has to turn, often to another page, much time, trouble and annoyance would be saved. The only redeeming feature is that the letters used refer to English words, whereas in some of the text books which borrow foreign cliches the trouble is augmented. The present writer was, in fact, so impressed with the need for reform in this matter that in any biological illustrations which he has prepared for students' use he has always h.ad the full name of the parts inserted. In these days of cheap line-process reproduction the extra cost need not be considered. W. M. W. x()ticp:s. PHOTO-MICROGRAPHY.— On Monday, May 6th, Mr. Edgar Senior will begin a course of six practical demonstrations on Photo-micrography at the South-Western Polytechnic Institute, from 7.30 to' 9.30 p.m. At these demonstrations special attention will be given to the photographing of etched surfaces of metals and alloys (Metallography), but the course will also be arranged to suit the requirements of students of Geology, Botany, and so on, and of those wishing to use their own microscopes to obtain photographic records of objects. It is advisable that students joining this course should possess an elementary knowledge of photographic manipulation. Fee for course. 2s. 6d. A NEW SCIENTIFIC QUARTERLY REVIEW.— On the first Tuesday in .April. Messrs. Constable and Company will publish the first number of Bedrock, a quarterly review of scientific tliought. The editorial committee consists of Sir Bryan Donkin, Professor Poulton. Mr. .\rchdall Reid. and Professor Turner, while the acting l-Iditor is Mr. H. B. Grylls. Bedrock is an attempt to provide an arena in which thinkers possessing a common knowledge but divergent opinions can meet and endeavour to thrash them out. We sincerely hope that the editors of the new review will find ample justification for their belief that there are few scientific or social problems of which the solutions would not be hastened by the provision of such an arena. Knowledge. With which is incorporated Hardwicke's Science Gossip, and the Ilhistratcd Scientific News. A Monthly Record of Science. Conducted by Wilfred Mark \\\h!). F.L.S., and E. S. Grew, M.A. M.w, lyii. AN LM14{0\ED TOEPLER PUMP. Hy H. J. GR.\Y. \Vhi:n working with a Toepler pump in the produc- tion of high vacuua, the necessity to refill the mercury reservoir from time to time is a source of incon- venience. To remedy this defect the writer has successfully adopted the device described in the following para- graphs. The principle will be esident from Figure 183, which represents the essential features of a typical form of Toepler pump. Instead of a single reservoir, two equal mercury-contain- ers are used. These, it will be seen, are connected to the branches of a Y tube fixed in an inverted position. Each branch should bi' tapped or, as a substitute, strong but easilv operated spring clips might be used on the india-rubber connecting tubes. A screw clip would be too troublesome. The receptacle, C, containing the end of the eject tube, has a tubulure at the side, Figure 1S3. .-^n Improved Toepler I'nnip. into which is fixed a perforated rubber cork, having provided w ith a mercury trap if considered advisable one end of a bent glass tube passed through it. To the lower end of this is fixed a short rubber tube and glass jet. Let the reservoir, .\, be filled with mercury, raised and supported in an appro- priate manner. The tai). D, being open, the mercury passes through the pump in the ordinarv manner and ultimately reaches the vessel. C. Overfiowiiig through the bent glass tube it falls into the second reservoir, B. which is supported imme- diately beneath, the tap, E, being kept closed. Thus one reservoir is always filling automatically, while the other is discharging. When A has become empty it is the work of a moment to raise the mercury for another fall. Simply reverse the position of the reservoirs, always opening the tap communicating with the nil one and closing the other. It is lilt necessary to fit a tap to the vessel C, since the mercury is always flowing through the bent tube except for the moment while the reservoirs are being changed, when the short rubber tube may be closed by pressure between the fingers. .\ three-wa\' tap ma\' be substituted for the tapped Y-piece with equally good results. It should have a bore of about two milli- metres, and may be TIM': sr\i)i-:w a r.K'rrisii ixsixt-hatixc. plant r.\ I. IlMloKD Dl Dl.l \ lU XION anm I'llII.I r.AkKMl). F.E.S. Tliosic who arc fund of dabbling in old books as well as searching out flowers in the field, will find the subject of our pajier thus described by the botanist Kay : — " Sundew, or Rorella, of which the distinguishing marks are: the leaves are fringed all round witii reddish bristles, to which little drops, as it were of di'w. stick, etc."* Curiously enough, this keen old observer does not mention the fact to which most people owe their interest in the plant, namely, that it is carnivorous. It is customary to make the rough generalization — inaccurate often in detail, though true in principle as so many generalizations are — that plants can feed on inorganic substances while animals need organic food. This may be briefly explained as follows: — We are all familiar with the old division of the world into animal, vegetable, and mineral. If we include under mineral everything, such as air and water, which is neither animal nor vegetable. we shall have the matter clear. Organic is animal and vegetable, inorganic is everything else, .\ninials, then, need organic food : plants can. with some excei)tions, do without it. from wliich it follows that. whereas plants could li\c witJKuit animals, animals could not live without plants. But if we turn to the Sundew we are imme(liatel\- confronted with an exception, a plant, which has so far forgotten w hat is the usual nature of plants, as to feed on meat. The time has gone past when science was allowed. or indeed expected, to ask "win'," but it is our dutv to ask " how." Now it will be noticed that the three ISritish genera of insect-eating plants, viz., Drosera (Sundew), Pinf>iiiciila (Butterwort), and Ufriciilaria (Bladder- wort) live in marshy districts. It is probable that to live in marshes and stagnant pools is to be in a place where starvation is always a possibilitv. These plants have found a method of getting out of the difficulty by adopting, partially or entirely, a new- diet. But to digest new food materials new methods were necessary, and it is a curious fact that the Sundew manages to digest the animals it captures in a way not unlike that in which we ourselves digest food. Trom this we may deduce the interesting fact that a similar problem is solved in a similar \\a\-. Such a condition is of special interest at the present day, because of the various evolutionary theories that are being put forward. It is said bv some writers that every living thing has in it main- possibilities which are not alwavs fulfilled, and that. given the same circumstances, it is possible for li\-ing things, though of widely different classes, to solve the same probleiiis in preciselv the same way. The Sundew is an instance which might be adduced as a case in point. There are, of course, many objections to the theorj-. Let us now- consider the Sundew in detail. The photographs here reproduced were all taken from the same leaf at intervals and are enlarged twice natural size. It will be seen (from I'igure 1.S4) that the leaf is furnished with a large number of specialized hairs. Each one bears at the extremitv a gland which is very sensitive to the slightest touch, and which secretes a drop of sticky fluid. It is possible that insects when in want of moisture visit the plants in the hope of satisfying their thirst, being attracted by the drops of fluid resembling dewdrops, but when once the\- have touched the leaf they are usually unable to disentangle their limbs from the sticky substance. The insect in its endeavours to get free is almost certain to touch some of the other hairs, and these help to hold it until it is hopelessly entangled. If we watch very closely, we shall see in a few moments that the hairs, which have been touched, begin to bend inwards towards the middle of the leaf carrving the insect w ith them. Soon the imfortunate captive is brought into contact with the next row- of hairs. These in turn bend, carrying it further inwards, until it is in the middle of the leaf and in contact with the short hairs of the central disc. (See Figures 188-191.) Then from the last-named some sort of impulse radiates to all the other hairs, and soon the insect is clasped from all sides and enveloped in the secretion. (See Figures 192-195.) The length of time which this takes varies con- siderably, from under one hour, to as many as twenty-four or e\-t'n longer, and depends on the age and consequent vigour of the leaf, the tempera- ture of the atmosphere, and many other circum- stances. An insect, however, generalK" dies in from fifteen to thirty minutes owing to its breathing tubes (spiracles) becoming clogged with the secretion. A leaf usually remains closed over a fly for some da\-s, then slowly re-opens, exposing to view the harder parts of the insect, which have not been digested. All secretion then dries up for a time and the undigested parts drop off, or are blown awa\-. Then the leaf again begins to secrete in readiness for another meal. It is frequently stated that it is not possible to deceive this plant, and that it w ill take no notice of little jiieccs of stone or similar objects if they are l)laced on the hairs. This, however, is not always Kos solis sen Korclla, cuius iiotae folia setis rubentibus circuin quaiiue fiiiibii;U;i quibus ^uttulao rclut roris ailliaerent. and so on. — Ray, " Ntetliodus Plantaruni." 166 FiGLKL 1S4. I'iGURE 185. Figure 186. Figure 187 is the same as Figure 186, seen from the side. Figure 188. Fici^iu-; 189. Figukk 190. Figurk 191. Figures 189 and 191 are side views of the leaf as it appears in Figures 188 aucl 190. Figure 192. Figure 19J. Figure 194. Figures 193 and 195 are side views of Figures 192 and 194. •iGUkl-. 195. The Leaf of a Sundew {DrQsera) taken at successive intervals when " feeding " on a Fly. Twice life-size. The Fly was of a species a little smaller than the common House-Fly. Plwtografhs by Philip J. Ilarraud, F.E.S. 167 KNOWLllDGR. the case, as ovimi iniiuite piccfs of stoiU', pajjcr, wood or glass ari' suHicient to cause movement, provided tliey are lieavy enough to penetrate the secretion and touch tlie gland, hut the action is often slower and less complete than if meat or insects were used. Raindrops, however, do not seem to cause movement : on the other hand, the leaves are very nuicli affected by the application of a finger. We have so far been considering the "indoor" side of the Sundew — let us try for a few minutes to search for it out in the sunshine. To show the plant association in which it lives we may give a picture of a favourite hunting ground. This is a marshy piece of ground through which a stream flows, shut in by steeply-rising rocks, in the hollows of which grow oak trees. The essential point for our purpose is the absence of cultivation. Round the marsh there grow many of the sweet-scented i)lants. mint, and marigolds, " which go to bed with the sun and with him rise weei)ing," and other flowers of middle summer, as Ferdita calls thein. There are some lf)w bushes of sweetgale and tufts of heather. To drain off the excessive water, a ditch has been cut through the peat. On the banks of this grow Meadow Sweet, Pur|)le Loosestrife and Hutterwort. The marsh itself through which this ditch runs is a \ivid green tinged with red from the Bog Moss which fills it. Here the Sundew grows in great abundance, and the tinge of its leaves adds to the colour of the Sphagnum. In one corner, where the marshy character gives place to swamp, the cotton grass becomes prominent, then reeds and horsetails and, finallj-, on the open water, water lilies float. A COLOSSAL KLINFORCLD CONCRETE STATLE. Hv I'KANK pI':rkins. Thk accompanying illustrations show the remark- able reinforced concrete Indian statues of Lorado Taft"s design, as unveiled in 1911 at Eagle's Nest Bluff, Oregon, Illinois. This colossal statue of the famous Indian chief " Blackhawk," overlooking the Rock River. Illinois, was jiresented to the peojile of the state. It measures forty-two feet high with a base of six feet, and was erected on a natural rock\- bank two hundred and fifty feet high, overlooking the river. The total height of the concrete statue measures forty-eight feet. .'\ French reinforced concrete statue was recentlx' erected in Espaly, Loire Department, France, and is also entirel}" made of reinforced concrete, the pedestal and the figure of .St. Joseph together being seventv-two feet. A threc-storv tower. twent\-fivt; feet in diameter, and 24-4 feet high, forms the base. Within this base are seven columns in a circle, which carry the weight of the statue itself. The figure, weighing eighty tons, measures forty- eight and a half feet in height, and is composed of a framework of reinforced concrete about which the outside mantle is fitted. The framework in the main is made up of a vertical shaft w ith a tube at the top which forms the axis for the head. There is a series of nine horizontal platforms in the various sections of the hgure which supports the exterior coating of the figure. It is stated that the statue was moulded on the ground and fitted around the framework, all traces of joints being effaced by a proper finish, so that the entire statue seems to be a singK' structure. <^I FiGURK 196. In course of Erection. •iGCUli 197. Tlu- Mould of the Head Figure 199. The finished Statue. Ihe Concrete Statue at Eagle's Nest, Bluff, Oregon. A SIMPLE METHOD OE EIXDIKG THE l^ADII VECTORES OE A COMET'S ORBIT. P.v THOMAS ASH1-: ('Ri;(;\N. To illustrate this method I hn\(' taken Comet 1908, c, the positions of which are those given hy Professor Kobold in the Asfronomische Nachrichten for Berlin mean midnight on the 2n(l, 4th and 5th October, 1908, the corresponding Greenwich mean time being 11 hours 6 minutes 25 seconds. According to the Eii^jUsIi Meclujiiic, Vol. LXXXN'III. No. 2274, page 282, these positions are subject to a correction of 90 seconds to add to the Right .Ascension and l'-5 to subtract from the Dcrlination ; thev then are as follows : — 2nd. 4th. 6th. Comet's R.A. ... J13' 51' 0" 308° 10' 30" 303" 34' 15" Do. Dec. N.... 70° 4' 48" 67° 26' 42" 64° 30' 42" The corresponding places of the sun being — 2nd. 4th. 6th. Snn's K.A. ... ISS 34' 21" 190° Zi' 26" 192° 12' 32" Do. Lont;. ... 189 20' 20" 19riS'34" 193° 16' 52" Find the earth's orbital motion between the obserxations. that is, from the 2nd to the 4th and from tile 4th to the 6th, and resolve each separately into two components, one a motion almost directh' away from the comet, the other a motion in the same direction as that in which the comet, whose motion is retrograde, is moving. Since the comet is at a finite distance, its positions are dependent upon our point of viexN', that is, upon the place of the earth in her orbit. The Declinations must therefore be reduced to the mean Equinoctial and the Right Ascensions corrected for the angular difference between the directions of the first point of Aries as seen from the sun and from the earth, at the instant of observation. Also, with the components of the earth's orbital motion we must reduce the places of the two last observations to that of the first. The corrected and reduced places of the comet then are : — 2nd. 4th. 6th. R.A 305° 16' 39" 295= 21' 16" 286° 28' 30" Dec 71° 13' 48" 68' 51' 24" 66° lO' 42" And these referred to the plane of the Mcliptic give— 2nd. 4th. 6th. Geoc. Long. ... 286= 44' 32" 282° 58' 42" 279' >' 50" Geoc. Lat. ... 49° 49' 3Z" 46 32' 47" 43° 14' 42" From the foregoing data we next find the \alue of r at the first observation, for the angle P = 97"24' 12" and of the two sides, PS' = 40= 10' 28" and PS = 90°', whence SS' is found to equal 1-57937 in parts of radius, and this is the value of r at iiiiif distance. Now, of the three bodies with which this problem deals, viz., sun, earth and comet, since the sun may be considered as stationai"}-, it is evident that if we eliminate the effects of the earth's orbital motion in the iiUer\al between iIk' (ibser\alions from the angle P, we will have tlu; values of P' and of P", and a siinple propf)rtion will give the values of r' and r". assuming for the present that the cornet's motion is uniform, therefore — 97°-403 : 96''-0694 :: 1-57937 : 1-55745 r' Also— y6°-0694 : 94°-59526 :: 1-55745 : 1-533841 r" These are the values of r' and r". determined from that of r on the supposition that the comet's motion is uniform. This, we know, is not the case. The comet's motion is increasing ; therefore r' and r" will both be too great by a quantity equal to the second difference of r, r' and r", which must be subtracted from the values just found. We have next to find ■■ c," or the length of the arc of the orbit which the comet appears to describe between the first and last observations. Using the same formula, we have ; P = 7"41'42". PS' = 40° 10' 28", PS = 46° 45' 18", which gives S'S in parts of radius as -142097, to which we must add -00227 the second difference alread\- found, and we obtain finally : — r = 1-57937. r"^ 1-53157. c = -144367 all at unit liistcjncc. w ith w hich to satisfy the equation. 3651 ^'=-12^ 2 t = 8 days also (r + r" + cli! - (r + r ' - c)i 365-25 37-6992 9 ■ 6885 ; therefore. 8 ^^r-^. = -8257 which is the number that we have 9 -6880 to obtain by trial values of r, r" and c, in order to satisfy the equation. Using figures to the fourth decimal place only, I find that 1 •0537 gives -8255, which satisfies the equation within -0002 ; therefore the radii vectores of the comet's orbit on the dates computed are : — 1 -6641 1 - 6642 1-6389 1-6137 1-63SS 1-6136 Professor Kobold givc« To find the corresponding distances of the comet from the earth, or the values of D, D' and D". In the triangle CSE, formed by the comet, sun and earth, we have foimd the side CS, which equals r, and SE = R, is known from the Greenwich date of the observation, we have therefore to find the angle at E. Taking the comet's R.A. at the first observa- tion, add to it the angle T SE and reduce the observed declination to the apparent equinoctial of the date, we then have corrected R.A. = 322° 25' 21"; rednced Dec. = 71° 49' 3". and these referred to the plane of the Ecliptic give ;n()\vij.1)c. i: May. 1912. thf aiigli- at !•: = 104" 46' <)" and the aiij^lc at S = J9" 41' if)", therefore D = 1 ■()')'){)7 in jwrts of radius. Wliilo D' and D" may be found in liki- niaiimi. takinj; care to add to the corrected R..\.. the \aiu(; of tlie eartli's orbital motion in tlie interval, it is not necessary to undertake this laliour, since we onl\' require to know the change in the value of tlie angle at E. Indeed, since D' is not involved in tlie computation of tlic elements of tile orliit. it mav be neglected. To find the angle at E at the second and third observations, we have seen that the difference between P and P' = r' 20' 2". Now the angular motion of the earth in the ecliptic in the interval is 1° 58' 16": therefore, the difference between these two, subtracted from E at the first observation, gives E' and we have E'=104" 7' 55" and thir angle at S' = .59 .56' 0" and 0'= 1-0772. Similarly, the differ- ence between Pand P" = 2 48' 29" and this subtracted I mm .5 56' J2", the angular motion of the earth during the interval between the first and last obser- vations, gives a correction of 1 ' 8' .5" by which the the angle E must be reduced to give E" ; we have finally, therefore, E"=103-^ 38' 6", and the angle S" = .59" 22' 15" the resulting value of D" being 1 ■()5.}.5. The distances of the comet from the earth on the dates computed are, therefore : — 1-0990 1-0772 1-0533 Professor Kobold gives... 1-099 1-0743 1-0532 Such, in brief, is a description of a method of deal- ing with this problem, which is concise, easily followed in detail and is independent of any special formulae. AN IRISH PHARMACOPOEIA. Hv .\1. I). HA\IL.\XD. In most places the time-honoured vocation of herbalist or " wise woman " is extinct, but here and there in out of the way corners of the "Emerald Isle" she still plies a flourishing trade. Some of the rustic remedies have a certain foundation of truth, but more often they are based upon pure super- stition. For instance, in cases of jaundice the Dandelion {Taraxacum officinale) is justly regarded as a valuable liver tonic ; but on the principle that " like draws to like," the virtue is supposr;d to reside in its yellow colour, and the Yellow wort iBlackstoiiia) and Saffron are used for the same complaint. In County Kilkenny, a horse with colic is treated with soot, a remedy which might possibly give relief in cases of indigestion and flatulence ; but what can be said for " a shrew mouse boiled in milk," which I was solemnly assured was a sure remedy for any weakness of the kidneys ? The whooping or cliiii cough, as it is called in Ireland, carries off a large number of peasant children everj' year, and consequently many remedies are recommended. A favourite medicine for this complaint is donkey's milk, which, no doubt, does work wonders for ricketty children who have been reared upon stewed tea and Indian meal ; but superstition has stepped in and declared that the patient must be passed three times over and under the animal, and then soatc^d upon her back. In County Cork an infusion of the Thang-an-uann or Stitchwort (Stellaria liolosteaj, sweetened with sugar candy. is also considered eflicacious. Snails boiled in milk arc thought excellent for consumptive patients ; and the Coltsfoot and Marsh-Mallow are justly esteemed as remedies for bronchial affections. In some places the leaves of the Colts- foot {Tiissilago) are supposed to "draw" sickness to the house, however. Along the west coast of Ireland there is a belief that the Common Plantain iPlantaga major) is good for such ailments as ringworm or parasites in the hair; while another plant of the same family iLittorella juitcea) is reckoned a sure safe- guard against hydrophobia. The properties of the Foxglove (Digitalis) are fully recognised by the Celtic herbalists, but Miss Sargent, to whom 1 am indebted for much interesting information on this subject, tells me that cases of poisoning are not uncommonly traced to its use. A decoction of the stem and leaves in water is a local specific for making the hair grow, and is also rubbed on saddle-galled horses, and on dogs and cats with mange; but if it be applied to any part which the animal can lick, poisoning often results. In the curing of warts superstition has full play. If you should meet a funeral while suffering from these growths, you should turn and walk three steps with the procession and then bid the warts go to the burial. This is a radical cure. .Another plan consists in burying nine blades of Timothy grass ; as these decay the warts will disappear. Yet a third remedy practised in CountyCork is to anoint the growths with the acrid juice of the Euphorbia hiberna. and this is probably the most effectual of the three, as this plant has caustic properties. Many of these rustic cures owe their efficacy less to the virtues of the " medicine " than to the method of their application. For instance, a remedy for sprains is potato water, but as this is applied as hot as it can be borne, probably the benefit is derived from the hot fomentation ; and " crane-oil " — the yellow fat of the heron — is considered good for rheumatism and lumbago, but here again it is most likely the massage in applica- tion which gives relief. Yarrow tea is another remedy for rheumatism, and so is a potato carried about in the pocket, but this last is most effectual if begged or stolen. The little bones under the black markings of the haddock — supposed to be the print of St. Peter's fingers — are also carried as charms against toothache. Eel skin is supposed to protect swimmers against cramp — perhaps some properties of the agile fish are thought to linger in its dried epidermis. If anyone has a festered wound caused by a piece of metal, the latter — a nail, a bit of jagged iron, and so on — must be stuck into a raw potato until the sore is healed, otherwise it will mortify, .\fter these, and kindred superstitions, it is interesting to learn that these \illage physicans are quite aware of the medicinal properties of the Gentian tribe, and recommend the Common Centaury as a tonic for young girls who lia\e outgrown their strength. No doubt the simple faith with which many of these old cures are used does more to relieve sickness than the medicine itself; but most of them are harmless, if not always very appetizing. Now and then, indeed, one is surprised to find to what extent modern pharmaceutists have been forestalled by these old herbalists of southern Ireland. THE ERUPTIOX OF USA-SAX AXD THK FORMATIOX OF A XFW MOrXTAIX IX lAFAX. Bv CHARLES D.WISOX. Sc.l).. I".(;.S. The eruption of Usii-san in Japan, which took place in the sutnnier and autumn of 1910, was in no way remarkable for its violence or duration. Nor was it attended by any loss of life, for the police wisely took precautions in time and removed all the inhabitants of the disturbed region beyond the reach of danger. But few eruptions have con- tributed more to our knowledge of the volcanic mechanism : and the formation of a new mountain, not by the accumulation of ashes, nor by the over- flow of lava, but by the actual upheaval of tlie ground, is a phenomenon that is certainly rare in our annals (^f volcanic action. Fortunatelv, the different phases of the eruption were witnessed by an observer of wide experience. Professor Omori, the director of the Seismological Institute in the Imperial Universitv of Tok\-o, paid two visits to the district, one during the course of the eruption, and the other three months later, and his first report, which has recentl\- been issued, contains so much that is of interest that a summarv of it mav be useful. The mountain of Usu lies in the south-western portion of Hokkaido, the northern island of the Japanese empire, a little more than fift\- miles to the north of Hakodate, and on the north-east coast of Volcano Hay (Figure 200). In the same district there are three other volcanoes, Makkari-nopli, twent\- miles north of Usu-san, Tarumai-san, thirt\' miles to the north-east, and Komaga-take fifty-four miles to the south. Between these volcanoes there is evidently a close connexion. In 1874, there was a great eruption of Tarumai-san, after which, for nearly thirty-two years, no outburst of any import- ance took place in Hokkaido. In August, 1905, the recent period of volcanic activity began with an eruption of Komaga-take, which lasted a fortnight. This was followed in January, 1909, by a remarkable eruption of Tarumai-san, which lasted more than tliree months, during which a lava-dome four hundred and forty feet in height was formed, and in July. 1910, by the eruption of Usu-san, here described. There appears also to be an intimate relation between the volcanic and seismic phenomena of the district, ("ommon as earthquakes are in certain parts of Japan, the}- are comparatively infrequent FiGL'KE 200. Map of part of the Island of Hokkaido visitors in Hokkaido. In April and .Ma\-, 1908, how- ever, about a year before the eruption of Tarumai- san, the Island of Rebun, close to the northern point of Hokkaido, was disturbed b\' numerous earthquakes and earth-sounds, the origin of which was under the sea to the south-west of the island (at A, Figure 200). On June 15th, 1910, or about six weeks before the beginning of the Usu-san eruption, a violent local earthquake, also with a submarine origin (at B, Figure 200), caused some damage near Rumoe. This was followed during the eruption, on September 8th, by another earth- quake, somewhat less strong, in the same district. Before these two, the last strong earthquake felt at Rumoe occurred thirt}-six years earlier, on Februarv 28th, 1S74, shorth' after the great eruption o( Tarumai-san. The origins of the earthquakes of 1908 and 1910, with those of earlier shocks in 18i4 and 1856 (at C and D, Figure 200), lie along a band (indicated by the broken line, bigure 200), which runs nearly north and south, passing through or close to Tarumai-san. Taking into account the rarity of earthquakes in Hokkaido, it is difficult to resist Professor Omori's conclusion that the relation between the earthquakes and eruptions of the island is not accidental. Usu-san is a comparatively small volcano. It rises from an irregularly circular base, about fourteen square miles in area, bounded on the north by the Lake of To\a. It is a flat plateau-like mass with a central crater, the longer and shorter diameters of which are about two thousand three hundred and one thousand eight hundred and sixty \ards in length. The north and south rims of the crater are one thousand seven hundred and seventy one feet above the sea. but on the east and west sides there rise two lava domes (O-Usu and Ko-Usu) to heights of two thousand two hundred and seventy and two thousand two himdred and fourteen feet, respectiveh'. The surface of the Toya lake stands at two hundred and seventy-nine feet above sea level. Before the last eruption, the northern slope of the mountain dipped into the lake at a small angle, so that along the southern coast of the lake there was a band of fiat ground three miles long and less than half a mile in width. At the east and west ends of this band are two hills, East Maru-yama 171 172 KNo\vi,i:i)r,i-. May. 101; and Kdinpira-yania. ciglit hinuiifd and littv-llinc and seven Imndri'd and ci^^lity-si'vcii Icit in licii^lit respectively. A little niore tlian lialf a inih' nortli- east of the latter, is a small roundcil liill called West Maru-\ania, five liundred and ninety feet liif^li. The last known criii)tions of Usu-san took |)lace in the vears 166J. 1769, 1822 and 185-5. those of 166J and 1822 were great eruptions, and. for two or three days before the first outbursts, were preceded by numerous earthf]uakes and earth-sounds. The same symptoms luialdcd the eruption of l''l(1. In the town of Nishi-Monbets. which lies about five miles to the south of the crater, twenty-five shocks were recorded on July 22nd, one hundred and ten on .lo the following day, three hundred and fifty-one on the 24th, and one hundred and fifty-two up ti> Id p.m. on Jul\- '" 25th. wlieii the first explosion occurred. The shocks, as illustrated by the lower curve in Figure 201, reached their greatest frefjuenc\' twenty-four hours before this erujition. During the immediateh' preceding twelve hours, only thirty- four were recorded. None of the shocks was of great intensit}-. Only two of them were strong enough to poorly-built houses, and both disturbed small areas. The upper curve in Figure 201 represents the be noticed that the first prcmonitor\' shocks occurred on July 21st when the barometric pressure was a minimum, and that the first volcanic e.xplosion took place on July25th,when the fjressure wasa maximum. Roughly, also, the variation in time of earthquake- frequency follows that of the barometric pressure. .---- ---^ ^ /" ^•^. y^ Barometric PrbBsure "-.^ ^ ^" r / Earthquake Frequency * / * / ^ / V -^ \ .First, Explosion. ^^ J v^ ■^N ^\^ 25th 36 "lOL'KK 201. lid the damage some Ko-Tipira-yaflia ~ fMGUKi-: 202, Plan of tlie Cvaterlcts. variation in barometic pressure at Hakodate, fifty miles south of L'su-san,'from July 21st to 29th. It w ill ustr.•lli^,^' tlip number of EartfiiiuaUc Slit; barometric pressure. The first volcanic outburst was a small explosion at 10 p.m. on July 25th, from the north-west side of Kompira-\-ama, followed by a second from the west side of the same mountain. These were succeeded by explos- ions from a number of new craterlets. On August 10th, there were at least twenty-eight crater- lets, but explosions from new openings continued to occur until the end of the vear. On November 12th. forty-five different craterlets (indicated by the small circles in Figure 202) were counted, the diameters of which \aried from one hundred to eight hundred feet. They are situated along three well-defined bands. The most important of these is a curve (.\ .\. Figure 202), rather more than a mile in length, about half a mile from the southern shore of the Toya lake and from six to se\en I hundred feet above it. It reaches from the western flank of East Maru-\ama to the eastern flank of Kompira\\ama. Two other bands diverge, one (C) at right angles to the principal band along the axis of West Maru-yama. and the (^her (H) at a small angle along the axis of Kompira-yama. Mav. 1<)I- KN()\\Li-:i)r,i:. 173 It is important to notice that, from the flat ground forming the southc-rn margin of the To\a lake and the scene of the new mountain, these craterlets were entirely absent. The first two craterlets, as alread\- noticed, were formed at the west end of the zone of disturbance. The third explosion took place at the east end, then followed three more at the west end, and then another at the east end. After this, they occurred along the /one C through West Maru-yama, and in the centre of tlu- principal band. A A. There was thus an alter- nation of activity from end to end of the area, terminating bv confine- ment to the central region. .Ml of the craterlets were formed in a thick laver of soft earth, and none of the explosions was of great importance. Most of the craterlets quietlv" ejected ashes and. except when explosions occurred, were unaccompanied by loud detonations or by earth- tremors. There was no outflow of la\'a from any one of them. Most were in action for a few days or hours only, ami then became completely quiescent. A few, hos\e\er, remained active for several days, and consequently increased in size until they were more than two hundred yards in diameter. When the eruption was at its height, the scene is said to have been magnificent, as smoke-columns could be seen issuing at once from six or seven different craters. Figure 203 shows eruptions taking place simultaneous- ly from three crater- lets, that on the left, known as the Kumantsubo cra- terlet, being one of the most active craters during the whole course of the eruption. Some interesting observations on the earthquakes originating from the volcano, especially at the times of the eruptions, were made by Professor Omori. He erected a portable horizontal tromometer and a vertical motion recorder, from July 30th to August 6th, Figure 204 new Mountains seen on the column of smoke. davs of August, the number of shocks recorded at Xishi-Monbets was about two hundred and ninety, of which ten were sensible to observers in the same town. The number of volcanic earthquakes recorded being about twenty-nine times the number of perceptible shocks, it follows that, if the tromometer had been at work on July 24th, when earthquakes were most frequent, the total number recorded would have been about thrt'c thousand eight hundred, or one ever}' twcnty-twi) and a-half scconils. In other words, the ground must have been in a state of almost continual trembling. .\ special feature of the records obtained near the Kumantsubo craterlet is the occur- rence of w ell - defined quick unfelt vibrations in addition to the proper volcanic earth- (|uakes. These small \ ibrations are termed by Professor Omori micro- frcinors. Thc\- were entirel\- absent at Nishi-Monbets, and rajjidlv die out with increasing distance from the origin. .\s a rule, moderate explosions in the Kumantsubo craterlet were not accompanied by marked micro-tremors, but violent explosions from this and other craterlets in the vicinity were accompanied, and often preceded for a few minutes, by well-pronounced micro-tremors. They also occurred when the smoke ejections from the different craterlets were very insignificant or even had completely ceased. It would seem that, if ex- plosions were pre- \ented by some temporary obstruc- tion in a craterlet, the pent-up steam and gases produced in consequence a series of minor earthquakes result- ing in the micro- tremors. On August 6th, Professor Omori discovered accidental!} that the eastern part of the south coast of the Toya lake (from D to E, Figure 202) had risen about a yard, causing the lake- margin to retreat about seven }-ards. At the foot of East Maru-vama, the movement continued, but at a at Nishi-Monbets, five miles from the crater, and decreasing rate, until, at the end of August, the total from August 6th to 10th, in a school at the foot of rise of the coast was about four feet, and the East Maru-yama and about three-fifths of a mile recession of the coast line about twenty-three yards, from the Kumantsubo craterlet. On the first two The elevation was not. however, confined to the KNOWLI'.Dr.I- May. 1912. shore of till- laki'. It was still more marked on tlio iiortliern tlaiik of the volcano, where an area aixmt three thousand yards long, and six hundred and twent\-live \ards wide was j^radually r.iiscd until it became a new mountain. The area, which is repre- sented by dotteil shadiii},' in I'ifjure 202. is bounded on its southern sitle by two lines of dislocation (I and II. Figure 202). which are parallel to, and just to the north of, the principal explosive zone, \ A. Professor Omori thinks it probable that the elevation of the new mountain began on or about Jul}- 21st, when the first earthcjuakes occurred ; but it was only after .\ugust 20th that its appearance began to attract general attention. Early in September, the elevation must have been far advanced ; for. on the 7th of that month, some houses, built on land which previously sloped at an angle of fi\e degrees, were overthrown in consequence of the increasing inclination. Two months later, the height of the ridge of the new mountain was found by barometric measurements to be six hundred and ninety feet above the level of the lake. As its height before the eruption began was only one hundred and eighty feet above the same level, it follows that the total elevation from the end of Jul\- to the beginning of November was five hundred and ten feet, giving an average rate of upheaval of a little over live feet a day. Some time before or after this, the process of elevation must have ceased and an opposite movement set in, for, during .April, 1911, the height of the ridge was found to be one hundred and t\\ent\- feet less than in the previous November. The new mountain is shown to the right of the column of smoke in I'igurc 204, the dome on the left of the ligure being O-Usu. The southern face of the new mountain consists of the steep surface of the dislocations (I and II), the height of the slope being about three hundred feet, its inclination varying from thirty to sixt\- degrees. The other side now slopes directly down towards the lake at an angle of about thirty degrees. It is probable that the slope is continued beneath the lake. If so. this would account for the rise, by more than a foot, which took place in the level of the water surface of the lake in the latter part of July, the rainfall at this time having been insignificant. Professor Omori regards the formation of the new mountain as the primary or fundamental disturbance, and the earthquakes and volcanic outbursts as secondary- or attendant phenomena. The volcanic energy of Usu-san, in his opinion, was manifested by pushing upwards the underground lava-masses beneath the three zones of eruption {A, B, C, Figure 202), the result being the elevation of the new mountain. In consequence of this action, fractures must have been formed below the surface, and the production of such fractures must have caused the premonitory earthquakes, the greatest frequency and intensity of these shocks coinciding with the epoch when the formation of the fractures was at an end. Then followed the explosive stage in the volcanic action, when, on the night of July 25th, the gases and vapours began to escape from the zones so prepared. The elevation of the new moun- tain was most marked after the epoch of maximum explosive activity, as the continued uplifting of the ground would meet with few obstacles once the actual dislocation had been effected. .AN .AEROPLAXK IXTKNDHD TO BE NON-CAl'SIZABLH. Bv FRANK C. Pi: K KINS. The design and con- struction of what is claimed by William P. Bary, of Paterson, New Jersey, to be a non- capsizable aeroplane, is seen in Figure 205. It is held that the object in developing this aero- plane was to maintain lateral balance and, at the same time, furnish a means whereb\- it would lie impossible for the machine ever to acquire an angle in descent from which it would be impossible for the operator to recover with the use of the controls. 1-IGlKI. J.