I \ i /\ KNOWLEDGE Y 0 L . II. AGAZINE OF SGIENC^ Plain lyWorded -Exactl^deseriSed CONDDCTED BY RICHARD A. PROCTOR. ]j£T Knowledge grow feom more to more." — Tennysoit. VOLUME II. JUNE TO DECEMBER, 1882. LONDON: WYMAN .^ SONS, 74-7(i, GUKAT QUEEN STREET. LINCOLN'S-INN KIKLDS, W.C. 1882. f INDEX TO VOL. II GElfESAL. iHAU, civilisation in the days of, 426 Adam's Peak, Ceylon, 4S9 Aids to the study of geology, 90 .^cohol, victims of, 25r 332; a naturalist's y» and aphides, 463; the mistletoe boufih, .UUnson, T. i.e. P., I trojWes, 10 R., L.l Altmi and water to exiinguisn nre, -i/o American Association, the, 192 electrician, the. the inductor, 8; electric cenera'or, 35, 71 ; electrical measurement, 160, 261, Sii, 4 ,449 Amateurs, photography for, 23, 35, 126, 196 American pronunciation, 397 .American railroad acddents, 398 .American signal service, value of, 413 .Analysis and svnihesis, 320 .Anatomical studies (review), 361 -Uicestora, our, the final mixture, 4 .\ncient mine, an, 333 Ancient works in Florida, 271 Animal vaccine, 312 .Animals in Xorway, duration of life of, 295, 325 Arf-ony Tr.Uope and th? Tiintt, 462 .\nti.coraet philosophy and history, 415 .Vntiquityof man in Western Europe; part III., 19; part IV., !^7 ; concluding paper, 273 - of modem Stated, .Astronomical observations on Mount Etna, 369 .Atmosphere of space, 451 Atomic phvsics, a problem in, 371 Attitude* of aninuils in motion, 255 Aucora, llie. 419, 431, 483 Autotimtit electrical apidiance to sif^nal trains, 476 B.iBVLuNU and Assyria, libraries of, 414 Babvloniau Calendar, the, 26 Backboned animals (review), 380 Balloons in war, use of, 271 Beard, Daniel C, a comfoand nest (illustrateil), 279 Berthon boat in a ;;ale, a, 272 Be-ant. Mr. Walter, mistakes in works of, 462 Bible Enk'lish (review), 296 Bicycle, cucriry expended in propelling a, 435, see ?«). 216 ntley (review), 216 review), 216 the. 10; too much work, 10 ; i'l?. 234, 219. ; ';i..te, the.350 . ^ . photo;:raphy for amatei :1 ; thi- u'-'i»' !■;■■ process, 55 ; sec also 126, 106 'wninjr, John, how to ride a tricycle, 67; the tricycle as an aid to photographv. M7 ; what will he the future form of the tricycle? 1»S;_ energy ri*quircd to drive bicycles and trievcles, 478 ir-Urv HI the Strand, 393 iri.l.'.'i.s in Greece, 240 lit rlli,-. und moths, 9, 24, 38, 05, 113, 217, 219, 276, CtLlvoiB. the Babrlonitn, 26 Camels duration of life of, 325 Carbonic a. id in the air, 280 Carrier niccons for naval service Cst.Tiul ir. a -Inin;;.- lillustrate. Chess colomn, 13 ; Vienna international ' 16, 31, 48, 63, 85; the complete score list, 103; see also, +44 ; end games. T>y B. Herwiiz, 32 ; Steiniti— Winawer game, notes on the, 122 ; games by correspondence, 121, 136, 173; mental photo- graphy for amateurs, blindfold play, 222 ; general remarks on the strategr of the game, 24^; how to construct a problem, 367; election of problems, 488; also see 138, 1S9, 2<>5, 23S, 254, 386, 303, 318, 334, 318, 383. 396. 410, 421. 460, 473, 501 Chesterfield, electric lighting in. 428 Christian Knowledge, Society for the Promotion of, publications of the, 36 ■ Clark, W. J. H., butterflies and moths, 9, 24, 58, 93, 113, 317, 331, 249, 276 Cleaning brass, 370 Clodd, Edward, antiquity of man in Western Europe, 19, 87 ; concluding paper, 273 Cloud, forms of (dlustraled), 173; in the air, 258 (illustrate.!) . 278 (illustrated), 32J (illustrated! Coal, consumption of, on American and En;;lish railways. •445 Coal-beds, 304 Coal tar and ammonia, utilisation of, 461 Cod liver oil, substitutes for, -443 Coffee and tvphoid fever, 3 1-4 Colour-blin,1ne4s in Russia, 370 Coloured reaction of atropine and daturine, 272 ' Combat, a terrific, 165 Co.Tiet, the. as seen during the eclipse (illustrated), 103 : discovery of a, 271 ; return of the, 328 ; path of, for December, 430 ; see also 309, 319, 333, 341,372,383 Comet, path of the (illustrated), 433 Compound nest.(iUustratedl, 279 Concise cyclopaedia, a (review), 3f'l Converting a negative into a posi ive, 193 Corset philosophy. 478 Corset-wearing, 429 ; as an aid to beauty, 495 ; in re- lation to health, 193 Cory, F. W.. the rainband spectroscope, 375 Cotton, spontaneous combustion of, 234 Crackle surface glass, 383 Cricke;, changes in, 253 . new viens on, 248 Crimes and offences, 339 Critics, on aome, 43 Crystals. 20, 52 Crvstsl Palace electric and gas exhibition, 183 DiBwix and revelation, 411 ; letter from, 383; views on religion, 397 ; on the existence of a God, 423 Dawkins, Professor, on the river-drift msn, 212 Dead Sea water, 350 Death-warning, ioo Deer m.)use, the (illustrated), 353 Desert*, new theory of, 330 Destruction of rare animals and plants, 4S1 Diet of the Japanese, 139 Divining rod, the, ;iSO Dogs barking at horses, 272 Draper, Dr. Henry, death of, 411, 417, 475 Druakenness, the use of, 181 Dumas, M., carbonic acid in the air, 280 Raktu, population of the. 3 Earthquakes, in the British Islee, 339, 373, 400, l»l ; in Herefordshire, 4siflcation. 19. 39 Great comet, I he. 413; 4--> (ilUitrated) allerv, the. . :o u.traled) . t-.iil : Schwedoff, 23' lUlL, definition ol, bv Pn.fe. Hair eels, 401 Uarris.'n, W. Jerome, F.O.i geologv, 90; geology of 3i>l; alid of Rhyl. 337 Havilaiid. Alfred, M.R.C S . ■ — - ■ ^, 162. I7«. 311.3 Heallh-reaorta, English imiiie, 3, 18, 39, »l. 10 162, 176,311,306 Health, books on, 233 Health, the public. ai7 Hearing the Aurora by telephone, 140 Heal, school course on (review), SM Heliographic signalling from the Great Pvraniid, I Herring King, the (illustrated), 311 High tides, 204, 319 llincklev. Marv, the tree toa.1 (illustratedi. '2.11 History of tubitvle. tS Hiving lieea br electricity. 3i>9 Uollwm Kmtaurant, 3S.-t Holder, C. F„ a luminous .hark (illiutraled), 197; 1 1«. llil Iratedl, ,n, the amateur, 8 ; generatorf, ?S, 71 ; elec- y .nnd domestic lighting, 235 ♦ KNOWLEDGE ♦ How to riJe * triovcic, 67 HufiBinj. Dr. W ■. K.H.S.. pholosraphic spfHnim i J&oo, Will. an. K.C.S., crT!,liiU, 2'^, '•-: »*ur cl Jtpmif . die' of Iho. 139 J<-Il<rar ,-< of Kabvlonia and Assyria, 414 L '.r.v :, of B-nNition, 4,-.j I, f,- I,- ri- of a plant, 361 Lijhlii..!,;, effects of. on a house, 325 I,;l<-ni-_v .Tork tiad iosantty, 304 LUard. the poisonous, 263 London ColL-ge of Practical EnfnnMring, 336 longevity in Krusnia. 293 Louire. Chaldean antiquities at the (illustrated), 167 t,o«e. Dr. F. R. Eaton, n glass of vrine, 209 Luminous -hark, a (illustrated), 197 M*cBFTit. Ladr, by Madame Ristori, 112 Matniei Magn 411 "tism aud electricity (review), 34.1 ia in New RnKUnd, I'M antiquity of, in Western Europe, 87 Manganese ore, 476 Margale, sea-bathing ioflrmarv at, 263 Maatodon. the, 330 Mathematical column :— inverse probabilities, It; problems, l.i : the Una of probabilities, 30, 46. U2 : t.j our readers, b3; the problems of " Y " solved, 31, 269, 333; easy lessons in the differontiul caloilus. 83. 101. 120, 136. 154, 171, 188, 203, 237, 318, 346, 395. 412. 459, 473, 600 Uathematics and Science, 129 Meat supplies of the world, 319; product of the L'niled Stales, 476 Menacini: comet, the (illustrated) , 303, 327, 331 Mela- — Meieors, the Augusi ! at, 412 MidUnd accident, the, 385 Million Tears, a, 49 Mineral protiuclions in Rurope, 2»7 Minute l.fe. a study of, 37, 1U7, 259 Mirmce. in Sweden, 223 Modem dress (reriew), 193 Monk-ut nothing. 384, 106 Hanoxti. Oallery, the. Hm Hational game. >.tir. 161 Hational Portrait Callery, 334 ITatoralisfs year, autumn buds. 418; ants and nphide 4at ; the mistletoe bouKh, 477 New b, 310, 330 Ifoble, William, the division in the ring of Satun an. has the moon an atmosphere? 433 north Pole, i^Heotifle ol^ersations at the, I»2 Norwar, animals in, 295 novelist, death of a, 476 Oil lilli Opiam. the use of, 2^49 Organic bodiew, preservation of, 223 Oriental manai>cri[its, 240 Our anceatora, the Hnal mixture, 4 Onr hodi<»— t)on<« (illustrated), 467 ; Oar iiAti«iul game, 123, 164 Parallel Ne>v Testament, Path of the comet (illustrated). 453 Pearson, James, M.A., high tides, 294 Pebbles, notes on, 240 Photography for amateurs, 22; the gels 65, 120,198 Pilot-engines, 303 Plain ways in science (review) , 377 Poisonous liiard, a, 230 110; vej^elable poisons, 146, lUl Poker, 4*4 Polytechnic Institute, the, 313 Population of the oarth, 3 Postal Union, statistics of, 239 Potatoes, now use for, 39S Prevost. E. W., Ph D.. li'o-historv of h [iLint, 3«1 Procession of icebergs (illustrated). 168 Proctor. Richard A., winninj wagers, 5, 6; on some critics, 43 ; thought-reading, 51, 68, 108, 128, 161 ; the ores of science, 64 ; easy lessons in the differen- tial calculus, 120, 154, 171, 18S, 2II3, 316, 366, 395, ■159, 473, 600 ; stimulants nnd study, 125, 142 ; mathematics and science. 129; the Aususr meteors, 175 ; forms of clouds. 178 ; clouds in tho air, 208 (illustrated). 278. 326: tho British Association, 224, 210, 257; Mi.-ju-.- in C:iiKula. 217; V.-uu- nearing trmislt .;■:-■ [■■■.■■, j,l, ' ' ', T,'., i.| 418,451 ; the. type-writer, 1 '- , tl- I'- •- , '< ■ . i-ii'imi:; languages, 427. Hit. 11(7; .■..i-sel-ivwinnK, 12;i. Mr,; sun-spot theories, 431; stayed weakness, 4711 ; the Public health, the, 183, 200, 231 Railway speed, French and English, 435 Kain-band, the,293,307, 375 Barneses II , was he the Pharaoh of the oppression ? 1 31; the PhavHoh of Ji.<..|ili ? lij ; the .onsc.uliv Kale Pa-Tum, »n 1 Resear.li, I' I f, 295 Review, tli.-, H:t Kings, fairy, 127 Ristori, the Lady »facbeth of Madame, 112 Hiver-drift man. Professor Dawkins on the, 212 Ross, Lieut.-Col. W. A., R.A. (lesson V.), 23 Royal Academy, 1 Royal Aquarium winter electric exhibition, the, 191 Russell, Percy, future sources of our food supply, OZ, 143, 194; science in its application to domestic life, 245 Sands at Kirkcaldy, subsidence of, 350 Huod-storm, a remarkable, 223 Suturdny Recievi, the, aud Mr. Proctor, 239 Sutum. 'division in the ring of, 291; observation of (illustrated), 3i)7; ring of (illustrated), 329, 375, 389,420. S.ience and mathematics, 129 ; in Canada, 217 ; in its application to domestic life, 215 ; lectures for the people, IHl ; of the horse's motion (illustrotod) , 323; of the Time., 312 ; the eyes of, 51 .Sea-bathing inBrmary at Margate, 203 Sea birds, 250 Search lights for the navy, 326, 404, 118 Trees and tho Morlheru Pacilic Railway, 162 Tree-toad, the (illustrated) , 261 Tricycle, how to ride one, 07 ; for ladies, 95 ; as an iiiil to photography, 387 ; what mil be its future form ? 196 ; see also 178 TrolL.p.., Anthony, 175 Upheaving of land, Vkgktation, curios 355, 401, 41S (iUus- Watlle harii iii Auni, alia, 330 Wcutlier charts, 11, 21, 41, 07, 74, 98, 116, 131, IW, 107, 183, 200, 217, 231 Webb, T. W., tho great comet, 413 Weils' Comet, the photographic spectrum of (illus- trated), 89 Whist column ; *' Yarboroughs," 16 ; Coelobs on whist, 16; third hand play, 3i ; playing to tho chonces, ■17; with a bad partner, 221 ; a bumpor at whist, 61; the Milue cii ;;(....l play, 31, 104; returning the lead .t ;i I irfii r, i(»i; double dummy problem, 1.1 I, 1 . . I K'lmos, 174,221; the chanc... .. I . .. .ards nt whist, 187; 11. 1 ■, «l,i,l ca general conduct plain au..,.W7; of tho gamt .3112 also ,00 15, 17, lit, tH, r2ll, 137, ,'286 333, 317, 380, 393, 4'23, 159, 174 iUiams.'w. lattieu, electromanin 72, 129; fairy rings, 127; the use of drunkei ness, 181; the e, 401 atcd), 467; joints, of the sun, 416 ; h* 120 ; the atmosphere ol , Wilson, Dr. Andrew, K,R.S.E., found links, 121, 159; a poisonous lizard, 230; hair eels, 4 our bodies (ton. Wine, a glass of, 209 Winning wagers, 6 Wire guages, now scale for, 4^15 Wood, water frim, 207 Wrecks on the Iri«h i-oiibI. ho« COEEESPONDENCE. Ai CLMbtiTOa, an cCfeetive, 119 .Vdvanec of science, 407 Alcohol and inhcriU'd vice, 2:11; as a food, 250; in relation to brain work, 250; hingular effects of, 283 ; the now use of, 314; sec also 3U0, 331, 438 Animals, the artistic perception of, 169, 2.33 ^ KNOVS^LEDGE ♦ Correspondence — continued. Ant tngedy, an, ISO App&rent paradux in probabllitiee, 150 Arc on lunar diso, 437 Arnold, Mr. Matthew, on knowledge, 21h Artietic dot-, an. US Artistic pen-option of animaU, lt»9 "Anld Hol)in Qrn.v," t» Ballad, a (-uriou», 'Mi-l Ball-bearinj;s to bicjcles, 219 Bicycles, l.Sj Bicycles and their defects, 235 Bicycles, bal -bearings to, 219 Bicycles, defects of, 315 Botanical repulsTon and attraction, 263 Break for tuo-wbeeled vehicle, 97, 1 Breathing through the nose, 185 Brewing and malting, 422 Brilliant meteor. 185 British snakes, 49U CALCtJLATION a, 00, 185 Candle-flame, extinguishing a, 81 e, alteration i Coincidence, a singula Coincidences. 3Gt Cold bath at night, 361, 407, 422, 499 Cold snap, 133 ; in May, 28 : " Comet the (illustrated) , 457 Cone, seitions of a, 81 Consumption. 97 ; and t( sUys 2l>7, 299 Corset wearing, 393, 438, baeco, 28, 79, 117, 162 ; from Cycling and raricose veins, 169 Daoubbbeotypks, tarnished, 219 Death-warning. 439 Decimals, multiplication and division of, Dog, an artistic. 118 Doris tuberculata, the spann of, 93 Double star Castor, the, 150 Drama for amateurs, 219 Drinks, hot and cold, 189 Drunkenness, 2B6: n3e of, 314 Danman, the late Mr., 24, 79 Eaith, population of the, 12, 28 Earth()uakes in the British Isles, 457 Electricity in dentistry, 472 English >nabe, an. 361. 422 Extinguished candle-flame, 81 Fairy rings, 109, 184. 219, 235, 251 Ferguson, mechanical paradox of, 26B Fever tree. the. 41, 80 ,133 Figures of Ouid motion, 1 16 Figure-training by the corset, 331 Finlay Comet, the, 393 Fishermen and their superstitions, 364 Fish, intelligence in, KIS Flint instruments and pre-historic man, t<0 Flint-Jack. 2«7, 976 Fluid motion, figures of, 118 Full moon, time o^ 236 Glass of wine, a, 283 nlass >tvlographs, 29, 80 Cold in India, 60, 151 llAtR turning grey, 202; turning white, i:«, 161 Hamiltonian system, the, 485 Uemia and tnoycling. 202. 252 Highland Cell, the, 133, 26i) High tides, »H Hot drinks. Ml ■ hot and cold drinks, 235, 232 House-flies. t», 499 Hunter, Dr.. eiiieriments of, 316 llniley, Frofesi'Or. and .Marcus Aurelius, 117 ICBNRITHOX wasp, ,180 Imitations of \idcanic form and action, 117 Inspirometer, an, 152 Instinct and reason, 60 Iron pyrites. 422 -Unds Matthew Arnold on, 218 KNowLEnai:. Mr. LAPlnABlKs. 3il3 Lowofprohahilitii Loaf-oopj ing. 4W Leaminu'To sivim. Lifhinln.' ..(f...-l. Magnifying power, 29 Mnirpio, a reasoning, 3ty Marcus Aurelius and Prof. Huxley, 117 Mechanical paradox, 219, 282 Mental illusion, a singular, 314 Metachromatism 44 Meteor, 60, 133. 219 Mildness of the ^ea coast, 24 Milkv sea, the, 107 Mind trouble, H ver}' common, 1 ^lisplaced spa. 81 Modem surgeon's tools, a, 133 Monkey and mirror. 314, 380 », 438 ■1 probabUitit kohol on, 43S 8, new meliod of, 314 Bainhow, a singular, 202, 282, 361, 422, 49» Reason and instinct, 00 Keduclion of barometrical observations, 43H Satukx, rinss of, 314, 471, 485 ' School-Eirls. the Hlleen, 80 School of Telegraphy and Electric Engineering, 331 Small-pox. Miicaula\ Bpa, misplaced, 12, t Spectacles, SO Spiritualism. St.". ■ih. .361, 472 ,303 Tarnished dnguern'otypes, 219, 283 Tea and coUee, 100 Teasel, use of the, 458 Telegraph ^'^ Hehring'e Straits, IIS Terrestrial magnetism, 110 Thought-rending, 97 ; thought-rtiling, 132 : s 169, 219 Timbre of trumpet, 12 Toads, are they poisonous ? 169, 219, 252 Tobacco and consumption, 23, 59, 79, 117, 152 Tools of a modern surgeon, 133 Tree, the fever, 80 ANSWERS TO COEEESPONDEHTS. BV nn.) ..v,.l.illnn. 409 ii' !, . - iiM,,. shadow in water, 13 A«(roii..miral Soiiety, the, 253 Atianiie cable, how worked, 100 Augustine, St.. savings of, 99 Hall. Dr., luid thi< solar sysloro, 100 Balloons, lifting power, at seven milea' alti lleatrico and Benedick. 4t0 Heer .drinking, olieorvations on, 221 Ilic vi'U-, linw kept in a vertical position, 91 Mi. V, 1.-. riding, remarks on, 82 llliuvpipe In. ads, chnnge of colour in, 118 iiarks on, 332 cp-red from plants, 441 Cause, remarks on the great flrat, 10 Centre of earth considered to be solid, 99 Cetewsyo, observations on, 236 Chance, theories of, 100 Cloud bands, 394 Coil, how to make an electrical, 187 Cold snaps, meteoric theorj' of, 267 Colour of the human race, Darwin on, 2:30 Combustion of chemical substances, 100 Comet, tail of, as an cle<;trical body, 45 Comets, their attraction and the earth, 45 Crickets, how to destroy them, 332 Croll, Mr., and his geological investigations, 99 Dakikll cell, a, 316 Darwin, what he did not teach, 20; his views gene. rall^, 439 Day, shght alteration of. 13 Dejiression of d'stant objects, 2»4 Dryden on Chapman's" Busey D'Ambois," 3»4 Dynamo, driving, by steam, 8i Earth, the, its movement in respect lo the star sphere. 153 Eccentricity of cometic orbits, unsound theory of, 99 KcUptic, change in the o'diquity ol, 423 Egyptian chronologj-, 267 faster than the wind, 131 Electricity generated by masses of aqueous i Elementary atoms and heat, 101 Entomology, the study ol, 2.53 Evolution and M. Pasteur, 153 Fables, relerences to, 13 False scientists, 486 Flint-Jack, 268 Focus of a lens, how to cslculatc the, 30 Fog, explanation of, -kl8 Gas cooking-slovcs, remarks on, 101 Geraniums and pelargoniums, 208 , the cultivated varieties, 61 lalional art, 99 Gravitation and Dr. Siemens, 13 Gravity, acting on a buUet in motion, )S4 Oreennich time, 220 tiregorian telescopes, loss of light in, 187 Hamiltosiax raeihod of learning I rutin 380 liamiltonian translations, 409 Headache, cure lor, 2c'.< Heads and tails, calcnialion thereon, 346 Hercules, earth approa»-hing to, 99 Himalayas, the, and pressure on the earth, 13 Huxley, Professor, and the barometer, 30 Hydrophobia, alleged self-innoculationby (" IcV.-YAcnrs, how ihev - • • .. - Index, how to make Ol Index, observations on, 236 Intra-mercuri-l planet, an, 13 Insniite, 135 Italian, origin of, 29 Krw Gardens, 381 Khedive, its pronunciation, 17D Knickerbocker, iho word, HI Laplacb on Ihe duration of the earth, 103 Legrange and the duration of the universe, -15 Lightning, death by, 153 Light undulations' travel in enlarging spherm rouni the sun, 220 Lunar influence on the weather unscientific, 153 Li/anls and the Darwinian svsteni, 300 Mabs, th- inner sale lile of,'20J Maynuoth battery, the, 134 Mental and moral correlation, do trine of, 285 Mercury, a September transit of, Ml Weroupv, Greek name of. 45 Mens, oliject-glass by, 394 Meteors and their courses, 238 Meteors, remarkable. 31U Miles Engish. remarks on. 230 .Mistakes, how Ihey should be com^ted, 118 Mitchell, orbs of Heaven • v. 100 Momentum ofa liall, a problem worked out, 29 Moon, views and remarks thereon. ti> ; influence of, ci l,..,.iies, 100; spparenl dia i.eler of, 134 De, budget of paradoxes, 423; referenci to, 170 Morning lide-lable, how to make Motions of Ihe earth and resultai National portrsits. nn. 3»» Spectrum. Tilun>inc >n inhabitate.) botlj, 203, _• into the. 385 ' ' licht them. 10 » T»«. • <■■>. 2SJ Tirh.-U.M,.- ti„-.-Mi. ..T..v«J •< Todhunler.als'l-ra bv, 2»l ... , • ■ ■• '■ "'sproTed by Professor S53 VnlsicTioir. cruediM of continental, 236 ; see also 186.406 ValcanijtiiMr, methods of. 13t WariB and elactricilv, 153 Wheels, antiquilT of. ITi YiiST, alcohol in, is it dntro/ed in baking? 220 \vn, the, and how Muddock. SimpV 8ons, London, i*l .Vnatomiol aliidies. Ml Atlas, the botanical, bv 1). Mc.Upine, F.C. burgb, W. i A. K. Johnston, 216 .ourhood. b^^ftllB. W. Shore, F.O.S. Out.h i Coi, S-outhampton, 197 Hkit a '.I1....I ,..iir-e on, by W. Lardon, M.A. S.ii ■ - T, I M>-- .r.t r. r„l.r, -JW ScIl•^ . ,..,.... ,,[ .. r,. by W. Maltieu Williams. SiiaL' ' .•vll4Co..)« ^r-.'- ' V Thomis W. Shore, r.G.S. UISCELIABEOUS. Leatheroid, 193 Lectures by Mr. Proctor, 26 Life of a maxim lamp, 432 of equal lengths at the ' cllcct on New Orleans, 187 M.-uu!:i.iuLni.K lu, cxc-rcise, 218 Nkw ocean cables, 1 IB New South Welsh coal, 4W I'liuluKr-ilihiLal .Sucicty, a 1 Population of Japan, 118 Powder magazine s'luck by lightning, Tree ,71 ir.i/w*""* ^J' ''''l-l, tie, on Knowlkdgk, 4iM \Valcli-i;lii>.ses, coiwumijtion of, 498 Water-power lor the electric light, 93 Well, a myster.oua. H79 Western Union T<-legrnpli Company, 428 Whale snapping a lot-bnc, 483 Wild coffee-plant, making rope from the, 140 Wire-fencing in thi.uderstorms, 431 Women and tlie TtomIo University, 148 Women, dress of, 139 YsLLOW fever, fatal etlects in Cuba, 187 ILLUSTRATIONS. Amatkor electrician, the, inductor, 8, 9 ; ( ■iiart of linglunU and Wales, 162 n the air, 278, 279, 3ili | lie, as seen during the eclipse, 105 ; diagram | Diauu, the, •>!' the Loi Dove flower, the. 481 Fish, with phosphorescenl spots, 193 Forms of clouds, 178, 170 Grolooy of Llandudno, 305 Great sun-spot, Griscom electri Muotor, the, 390 g, the, 311 How to gel strong, 180, 181, 311, 332, 388 Hyla versicolor, development of, 203 IcEDKKOs, a procession of, 106 Lacukih, diagram of, 463 Luminous i.liark, a, 198 Mii.tAClNa comet, the, 327, 351 Moon, partial sobir eclipse of, 247 ; has the moon an alinosphereP433 New Princetown telescope, the, 360 Nights with a three-inch telescope (0 flguros), 21, 144, 146, 310, 339 Puotoohapuic spectrum of the comet (Wells'), 89 Procession of icebergs, 1(10 SATfttK, observation of, Mil- Science of the horre's motion, 323 Sea-squirt (Amaliroiicinm), Stars for July. 70; Augu October, 295 September, 419, 43 ^■:i:i;\ TaA^■•l TrBn~>. Vk.vi- Wahy TUMM.AT, map (. WaisU, figures of. 467 Weather charts, 11 June 2, 18S2.] ♦ KNOWLEDGE • LONDON: FRIDAY, JUNE 2, 1882. >^ Contents of No. 31. Science it the KoT»l Academy m'as Rameses II. the Pharaoh of the OppresaioD? Bv Amelia 1). £dvards. I.— The Argument of DeRooRe The Seaside Health Resorts of England. Bv Alfred Hariland. fopulation of the Earth Our Anccatora. IV.— The Final Milture. Bjr Grant Allen Winning Wagers. Bv the Editor . round Lints. Part Vll. By Dr. Andrew WiL=on, F.E.S.E., F.L.S. Home Cures for Poisons Amateur Electrician (IllurtnileJ) The Eclipse Butteraies an i M • , I' \'. J H.Clark Ma«andWci-t. i 1 MuchBrai^-^\.M\ 1' , ■ 1 . 1- Weather Charts t.ir \\ et-k Kndiii ; Monday. May 2a I Correspondence i Answers to Correspondents ' Our Mathematical Column I Our Chess Column I Oor Whist Column THE EOYAL ACADEMY. TO the lovers of the old-fashioned style of landscapes, with subdued mahogany as the prevailing tint, few |>aiutings in this year's exhibition will he more charming than Mr. Leader's " Morning : the Banks of the Ivy, O ! " No. 550, Gallery '\'I. The painting is, in fact, very pleasing, but it is not often that these tints are seen in nature. Certain French, Flemish, and Dutch paiiiters affect them, and we presume they must have seen them ; we have not been so fortunate ourselves. Facing this picture is one which will grievously offend all those who think that art should set the fa.shion to nature, Mr. Charles Stuart's " .Sunny Autumn," No. 627. Vi'e have «eldom seen finer and less exaggerated light than there is in this really charming picture. We have not a blaze of light in which all details are lost, as in so many of Turner's landscapes, nor have we staring contrasts, but a gentle light seems to shine through the landscape. The tender Autumn glow is rendered perfectly. Certain optical effects .are erroneously presented, however. The vertical reflec- tions (very faint, it is true) in the water, do not coiTe- spond to any feature in the landscape which in nature would cast such reflections. At an earlier or later time than that shown in the painting, when the shadows were more marked, they may have been seen, but not Otherwise. However, this painting is really so beautiful that we feel loth to touch on what is, after all, a very trivial fault. No. 5.")7, " Winter and Eough Weather," by 3Ir. Moore, seems intended as a parody on Turner at his wildest. In passing, we notice again a picture in the same i-oom to which we have already referred, — "E.xtremes ^leet," by Mr. Alfred Strutt — to explain that when we spoke of incorrect drawing, we referred not to tlie dogs but to the background. Considered apart from the background, the big fellow is a very tine dog, and the little " toy " beside him only duly small : but, considered with reference to tlie background, botii dogs look smaller than they should be. We must notice some of the portraits in tlie galleries of painting and of sculpture. But we are told that there is a great pressure on space this week, so we leave this to another occasion. We may, in passing, consider some of the water-colour paintings. "The Dying Day," by Walter E. Stocks, is \ ery finely painted, tiie etl'ects of the dying lights being well caught. Miss Kate Macaulay, in "Scotch Herring Trawlers," No. 804, and "A Sea Cliff," No. 9U, represents a very curious substance, on which boats are placed as they might be placed on the sea ; but it is not sea — nor have we any idea what it is — it is like nothing we have ever seen outside this lady's paintings. Mr. Arthur Croft, in Nos. 902 and 906 — the latter a magnificent painting — has admirably dealt with the difficulties involved in the correct delinea- tion of misty air in water-colours ; while in the "Port of Algiers, Africa," No. 917, he as skilfully represents the effects of an exceptionally pure atmosphere. In No. 1,056, " Hill-side at Assisi," ilr. Henry Goodwin tries to repre- sent a rainbow! " Coneysthorpe," No. 1,062, by Sir. Walter F. Stocks (it was hardly necessary to add to our last sentence that Mr. Goodwin utterly fails in represent- ing a rainbow), is a painting in the old-fashioned style, but very charming, too. We must ask Mr. Proctor about the moons in Nos. 1,09-1 and 1,099. The horned moon in the latter, "An August Evening," by Mr. Walter F. Stocks, is certainly unlike the homed moon as we have ever seen it on an evening when the air is so pure, — the horns being fluff\- in a clear sky. But can the line joining the horns of the setting moon in autumn be nearly up- right '] we always thought that they were at right angles to a line from the sun. [.So they are. We have seen both this moon and the moon in "Cairo from the Mo- hattam Hills," by Tristrsim Ellis (No. 1,094), (gibbous near the place of sunrise at early morning), and both are, in an astronomical sense, utterly wrong. Of the artistic qualities of either painting we would not venture, of course, to express an opinion. But we can see no earthly, or heavenly, reason why the hea\enly bodies should not be correctly represented in paintings, — even by Royal Aca- demicians. Is there anything inartistic in correctness T On the cover of the two first thousand of our " Easy Star Lessons " there was a sort of parody on Orion, and we were told, when we remarked on its utter inaccuracy, that it was meant to be artistic. Is the real Orion of the skies u';fortunately inartistic ! We note that iu the painting of " The Saving of the Capitol " — we have not our artist by us to tell us the number and painter, and the printers are waiting — there is a sort of attempt to represent certain familiar star-groups ; but the painter seems to have been afraid lest there might be something inartistic in putting in the stars as they exist in reality (or, it occurs to us as possible, he may think they have altered since tlie time of ancient Rome). It would be as artistic, I should say, to represent limbs and muscles incorrectly as tlie stars which garland tlie heavens. There is nothing essentially artistic in incorrectness. — Ed.] WAS RAMESES II. THE PHARAOH OF THE OrPKESSION? Bv Amelia B. Edwakd.s. L— THE ARGUMENT OF DE ROUGE. f^piIE busy, practical world does not, as a rule, concern .1. itself very warmly in matters of arclia>ological re- search, aiul rarely indeed has any discovery of a purely arclui-ological character taken so jxjwerful a hold upon the attention of the general public as did the recent dis- covery at Thebes. The first announcement of the decipher- ment of tlie Deluge Tablets by the late George Smith can alone be compared with it iu this respect ; but the ♦ KNOWLEDGE ♦ [June 2, 1882. enthusiasm with whicli that announcement was received neither sprcaove all, it must be remembered that but for • M. Chalxui, nn eminently learned and cautions Kg^-ptologist, pnbliBbcd an article nearly twenty years ago in his first eeries of " Melan(,'C8 E(ryptologi(|uefi," wherein he sought to identify the IlebrewB with a class of workmen called in Egyptian the Apcriu, who were employed to extract stone from the quarries opposite Slemphis during the reign of Kamoses II. Those Aperiu are twice mentioned in tlie reports of certain overseers of the works named Kaoiser and Keniamon, which re[>orts, written on papyrus in the Hieratic chanictcr, are among the treasures of the Leydcn Museum. Unfortunately for M. Chahaa's argument, however, a strict com- parative examination of numerous Hebrew words impfjrtcd into tho Egyptian language shows that tho Egyptians rendered the Hebrew 2/ by a combination equivalent to vp, and not by p, as inylpcn«; while the latest researches show the Aperiu to bean Egyptian tribe of whom mention is mode, according to Lenormant, as early as the VJth Dynasty. See Lenormahfs " Histoiro Ancicnne de TOricnt," vol. ii., p. 271. 18S2. the Bible we should know nothing whatever of the Hebrews in Egypt, nor of their final settlement in the Land of Canaan. For these important events the Bible is our sole authority. Its information is invaluable, as far as it goes ; but it does not go far enough. The stories of Abraham and Joseph, though told at some length, leave untold the very facts which would have determined their place in history ; while the period of the oppression, which must have extended over several reigns, is dismissed in the- briefest manner, and is so vaguely worded that it reads as. if all liappened under the rul(! of a single Pharaoh. ThesP are the missing links which puzzle Bible students and battle archa-ological inquirers. We may hope hero and there to bridge over a chasm or fill up a blank ; but it is impossible absolutely to reestablish the chain of events from Egyptian sources, so long as the cities and cemeteries of the Land of Goshen lie buried under enormous rubbish- mounds, which, in a corrupt but recognisable form, pre- serve to this diiy the ancient names of the sites upon which they have risen. I may at once pi-emisc that Egyptologists are, for the most part, agreed in identifying the PharMoh of the Oppres- sion with Rameses II., and the Pharaoh of the Exodus, with his son and successor, Menephthah I. This identifica- tion— originally proposed by tho late illustrious Vicomte E. de Rouge — has undoubtedly more probabilities in its- favour than any other. I will even say that it has, I venture to think, even more probabilities in its favotn- than have as yet been recognised ; and that some of these unrecognised probabilities are so conclusive that they very nearly amount to proof. Before, however, we proceed to an analytical examination of the evidence which connects this Pharaoh with tho period of tho oppression, it will be well to give a general outline of the argument, and for this purpose I cannot do better than translate tho following passage from M. de Rouge's preface to his " Notice Sonmiaire " of the Egyptian antiquities in the Louvre collection : — " The chronology of Egyptian history and the chronology of the Bible (especially when it becomes a question of esti- mating the period of the Judges) is altogether too full of uncertainties to enable us, (I priori, and by a simple com- parison of dates, to determine under which king the Exodus took place. The dilliculty is even greater as regards the time of the patriarch Joseph, liecause the length of time during which the captivity lasted is in itself a fruitful subject of controversy. Moses never employs any but the generic term 'Pharaoh,' which means 'tlie King.' But if we carefully note the salient points of the Bible narrative, we find, first of all, a king who compelled his slaves to build the city of Rameses, in Lower Egypt. Next, if wo calculate tho time during which Moses dwelt with Jethro, when ho fled from the wrath of the king ; if we remembeir that ]\Ioses smote the Egyptian just as he had attained t* manhood, and that, according to the Bilde, he was eighty years old at tho time of the Exodus, it will at once be seen that the reign thus indicated must have been excessively long. The Bilile say.s, in fact, ' After a long time, the king died.' But one Rameses answers to all these particulars. — na-nely, Rameses II., who reigned for 67 years, and who did actually build a city in Lower Egypt, to which he gave his name. Moses came back from Arabia as soon as he heard of the dpath of tho king whom he had angered. The Bible account of the plagues of Iilgypt, and of tho horrible catastrophe which attended the departure of tlu? Israelites, would seem to be compatible with only a limited number of yeans. Menephthah, son of Rame.ses II., is, without doubt, the Pharaoh of the Red Sea; Imt the Mosaic narrative does not give us to understand that the Jdne 2, 1882.] KNOWLEDGE king himself was among the victims of this disaster. He would seem, iu fact, to'have reigned for nineteen years ; and perhaps a less interval of time than nineteen years may have elapsed between the return of Moses and the passage of the Red Sea. Xo trace of these earliest rela- tions of the Israelites with the land of Egypt has been found upon tlie monuments; and it would, indeed, be extraordinary if the Egyptians had recorded this disaster in their temple-sculptures, which never commemorated any military events except victories." THE SEASIDE HEALTH RESORTS OF ENGLAND. By Alfred Havilaxd. IXTRODUCTION. IT is proposed to publish in this magazine a series of short papers on those seaside towns to which people usually resort, with the view not only of interesting them about such places, but of guiding them in the selection of the most appropriate to meet their peculiar health re- ijuirements. Hitherto, accident, popular caprice, convenience, or fashion have contributed principally, either collectively or singly, in rendering many places famous as health resorts. Some, however, have had their fame based upon more solid foundations, viz., upon the experience of learned and prac- tical physicians, who, after studying diseases generally in relation to the various factors' which constitute climate, have sought out the causes which iniluence their prevalence or scarcity, and have thus been enabled to recommend certain localities for the cure or alleviation of the diseases of their patients. Hippocrates, 500 years before the Christian era, taught tliis mode of investigation, especially in his immortal work on " Airs, Places, and Waters," and it would have been well had his teachings been more treasured and acted upon by liis successors during the last 2,000 years than they have been. However, during the last five-and thirty years there have been accumulated such a vast number of returns of deaths from disease, that at last it has become possible to map them in such a manner as to show at a glance throughout England and Wales where are to be found the favourite haunts of those causes of death which characterise this country's mortuary returns. On the other hand, the same map will show where these fatal causes do not or cannot thrive. Hence we have, on a grand scale, health- guides as regards certain classes of diseases, and we shall see in the sequel that, by a study of the principal factors of the local climate of any place, we gain a clue to the kind of diseases that would eitlier prevail or languish there. On the other hand, a map showing the dis- tribution of certain diseases will give us an insight into the physical geography and climate of the localities where they abound, or are rare. For instance, a map pourtraying the geographical distribution of rheumatism and heart disease will, at a glance, show the sites of all the closed valleys of England and Wales, for it has been proved that these causes of death are to be found in the greatest abundance, without exception, in all those districts where the valley systems are so formed as to preclude the possi- bility of their being air-flushed by the prevailing winds. Again, a map showing the distribution of consumption will have defined on it, in unmistakable groups, not only those localities where social causes foster it, but where the native populations cannot, when inheriting this terrible lung trouble, withstand the full unchecked force of the pre vailing wiuds. Such a map has all its exposed localities defined by the colouring of the high mortality degrees. One more illustration will suffice to prove our proposition that the physical and climatic features of a country may be predicted by a knowledge of its typical diseases. The remarkable distribution of cancer in females throughout England and Wales points out, by the colourijigof the higli mortality riparial districts, the courses of all the rivers in England and Wales that seasonably overflow their banks after wet seasons. Kow, all this information, however interesting it may b<;', would, after a time, cease to be so, were it not capable of being applied to our daily use. A knowledge of how diflferent diseases are distributed the great registration divisions of our countrj', its counties, and six hundred and thirty districts, teach us lessons and principles which would be valueless if not applicable to our to-svns, villages, and dwellings. The distribution of heart disease and rheumatism teaches us a grand lesson in ventilation ; it points out to us the true mode of street arrangement so as to ofl'er every facility for thorough air flushing ; it warns the invalid when seeking a health resort to avoid such as abound in gridiron clusters of streets, where diseases of the infectious class have their stronghold, simply because such a street arrangement pre- cludes thorough flushing of the air sewage. It teaches also those subject to or recovering from rheumatism or rheumatic heart disease, to avoid pent up valleys, however lovely, where the benign influence of the sea winds is shut out The lesson taught by the distribution of consumption must be remembered by those labouring under this lung trouble; they must not heedlessly select a health resort, for some there are which foster this disease, and even those which have a fair reputation for its prevention or alleviation, may have sites within their boundaries quite unsuitable for consumptive cases. Health resorts, especially those by the sea, are often selected, and, in many cases, very properly so, by masters and mistresses of schools for their establishments. Although at first it appears natural that a seaside health resort would be an eligible place for a school, yet we shall be able to show in the following series, that great pre- cautions will have to be taken by those having the natural charge of children and young persons, before tiiey send them away from home to be educated even at health resorts. We must remember that the period of education is the period of developmental life, and that whenever there are hereditary taints in the young blood, whether of cancer, consumption, rheumatism, itc, that such places should be avoided during the scholar and student life tliat are known to be favourable to the development of any of these and similar diseases. We shall endeavour, in the papers which will follow on the Sea-side Health Resorts of England, so to treat the physical geography, geology, climate, and vital statistics of each, as not only to interest the general reader, but clearly to explain the simple principles which sliould guide the health-seeker in the selection of a health resort POPULATION OF THE EARTH. A CORRESPONDENT (Mr. H. Percival) sends us the following question : — The land surface of tim earth comprises 52,000,000 */««irf miles. The most deusehi ftopulaled ret/ion {t\ut Flanders) has a population of about 700 to the square mile. J/ the whole la7id surface of the earth were on the averaye as densel;i KNOWLEDGE ♦ [June 2, 1882. peopled, Uii" earth's population iroithl b-' 30,400,000,000. Assuming the present population to be 1,500,000,000, and gripposing it henceforth to incrtase at the rate of 1 4 per rent. per annum, hoir man;/ //enn icould elapse before the earth'n /wptilation trouhl na-h'thin iiumber — i.e. 700 to the square mile of land / The population increasing in the ratio of 1015 to 1000 each year, if n he the required number of years, we have the following relation : — (l,.-)00,000,000) A9^^V= 30,400,000,000 \1000/ or 15(1 015)" =304 Taking logarithms of both sides, we have — n log. (1-015) = log. 304 - log. 15 or 71(0-0064000) = 2-.5011014 - 117G0i)13 _ 13850101 *"" " ~ 04600 = 21 4 1 years very nearly. Here is another curious question. Supposing the popu- l.ition of England and Wales to increase at the rate of U jier cent per annum, and not to be atlected l)y emigration, how long would it be before the population would increase from 20,000,000 till there would be one person to the s(juare yard, or, roughly, 10,000 times as many persons as tlierc are at present? To determine this, we have, taking . for the number of years, .1015y, Or, « log. (1015) = 4 T... 4000000 rin ^ Whence n = — —= Gl 9 years nearly. 0400 -So that, apart from emigration, war, plague, pestilence, or famine, the population of England and Wales, si.x cen- turies hence, would be one to the square yard. In a quarter of the above time, say in 154 years, the population of England, apart from such causes, would be ten times as great as at present, or there would be about -4,500, instead of about 450 to the square mile. : 10000 OUR ANCESTORS. IV.— THE FINAL MIXTURE. By Grant Allen. AFTER the English settlement in south-eastern Britain, two other ethnical elements of less importance were added at dirtV-rent times to the iiopulation of our islands. Both were originally Scandinavian (and therefore Aryan) by descent, but more or less mi.xed with other strains from elsewhere. The fir.st was that of th(! heathen Scandinavians from the north. In the eighth and ninth centuries, largo bodies of Danes and Northmen began to settle all round the coasts of Britain. In Ireland they occupied all the large river mouths and liavens, such as iJublin, Wexford, Waterford, and Cork, where they formed a set of Scandi- navian colonies which gradually coalesced with the native CeltrEuskarian population. In Scotland they seized upon Caithness, Sutherland, and Ros.s, on the mainland, to- gether with Orkney, Shetland, and the whole of the Western Isles, from Lewis to Arran. In Wales they founded a few minor settlements around the south-west coast, near Milford Haven. Finally, in England itself, they occupied all Northumbria (including our York.shire), all Lincolnshire, Norfolk and Suffolk, and the greater part of the midlands. Important Danish "hosts" had their centres at Derby, Leicester, Nottingham, Huntingdon, Northampton, and Bedford. Norwegians also settled in the Lake J)istrict, till then peopled exclusively by the Stratholyde \\'elsh. How large an element in the population these Scandinavian invaders formed it would, perhaps, be ditlicult to estimate ; but they must certainly have made a great accession to the number of light and fair-haired Aryan colonists. At the same time, since they came as mere pirates, they did not bring their women with them ; and they therefore int(!rmarricil with the people of each district where they settled. Nor did they at all exterminate the earlier inhabitants. In Ireland their blood was thus almost lost in the prevalent Oclt-lviskarian type; iu the Lake district and the Scotch lli;,dilands it has hardly had much more permanent in- lluencc ; but in Eastern England, where the Scandinavians intermixed with the purest Aryan stock left in Britain, tlu-y must ha^■e afforded a very considerable reinforcement to the light type, and their fair liair has certainly left its mark upon a large part of the population. The second Scandinavian admixture came later and more indirectly with the Normans from Normandy under William the Conqueror. These Normans were originally Danes like those who colonised eastern England ; but they had inter- married with the native women of Ncustria (northern France), where they settled ; and the Neustrians were, of course, Celtic Gauls, largely intermixed with Euskarian elements. ^Moreover, the Conquest brought over, not these lialflireed Normans alone, but many pure Celt-Euskarian - (iauls or Frenchmen from the neighbouring provinces as well, together with a considerable sprinkling of pure Celt- Euskarian Bretons from Brittany — a very dark stock, like the Black Celts of Ireland and Scotland. Accordingly, so far as numerical preponderance of the dark ''and light races goes, the Norman Conquest left things in Britain pretty much where they were before. Thus, then, to sum up the general result of this brief inquiry, we may say that the ethnical composition of modern Britain is somewhat after the following fashion. First, there is a substratum or oldest stage of dark, non- Ai-yan people, whom we call Euskarians for convenience, anil who are the descendants of the ^■ery earliest aboriginal inhal)itants in recent times, the Neolithic folk. These Euskarians are now nowhere to be found in very great purity, for they have married in with the later Aryan invaders till both are at present well-nigh indistinguishable. But thev are still found in a f.iiily unii.ixrd form among tin- iilack Celts of Ireland and Srothimi, uh.Te one or two litlle communities yet remain alnnisi iihuIIiiimI in the wilds of Connaught or the highlands of the central Scotch hills. They are also more Kj)arscly recognisable in many parts of England itself, especially in the Yorkshire plain, in Lincoln- shire, and along the Severn valley. And they are fairly freciiicnt in Wild Wale.s. All over the country, too, persons or families of this dark early type occur here and there sporadically. Indeed, it is probable that some relics of Euskarian blood survive everywhere in Britain, and that every one of us is more nr less remotely descended on one side or the other from neolithic ancestors. Dark children of true Euskarian type are liable to be born fiom time to time in alino.st all families. It may be well to add also, in a .science which is so personal to mo.st of us as ethnology, that there is absolutfdy no sullicient proof that any one type or race in Britain is mentally or morally superior to any other. We must not fall into the easy habit of sup- posing that an earier race is necessarily either a better or a worse one : the facts do not go to prove either supposition. Secondly, there is a superstratum or later stagi; of light Aryan people, who have broken over the islands in three distinct waves — Celtic, English, and Scandinavian, and JrxE 2, 1882.] ♦ KNOWLEDGE have everywhere mixed more or less with one another, and with the old Euskarian race. Ireland is, perhaps, mainly peopled by Euskarians, intermixed, in most parts, with Celts (but least so in Connemara and Kerry), while round its east coast there is much Scandinavian blood ; and in Ulster there are many Scots, who are really Strathelyde Celt-Euskarians from the western lowlands. So-called English settlers, many of them Welsh or Lancastrian, and others Xorman, are scattered throughout the Pale. But, as a whole, Ireland is probably more Euskarian and less Aryan than any other part of Britain. In Scotland, the north and the Isles are Celt-Euskarian, with a large Scandinavian admixture ; the Central Highlands are Euskarian with a very small Celtic element intermixed ; the eastern Lowlands are mainly English ; and the Western lowlands are peopled Ijy Strathelyde Welshmen — that is to say, Celt-Euskarians, probably with a larger dasli of Aryan Celtic and English blood than elsewliere. Wales is Euskarian at bottom, slightly Celticized, and with a little Englisli and Xorse blood. England itself is mainly English (or Low Dutch) in the south-east ; English and Danish, with a little Celt-Euskarian. admixture, in the Eastern Counties, the North, and the Midlands ; English and Celt-Euskarian in the West country, and the Severn Valley ; and Xorse and Celt-Euskarian in Lancashire and the Lake District. Cornwall alone remains almost whollj' Euskarian in type. All these statements, however, must be accepted merely in the rough, and they apply especially to the agricultural classes and the mass of the people. At the present day, the upper classes have intermarried all over the three kingdoms ; the mercantile classes have moved about till Mac's and 0"s are as common in London as in Perthshire and ^layo ; and even the artisans have poured into every great manufacturing town from all parts of the country. Ever since the beginning of the modern indus- trial movement, there has been a steady southward and eastward return-wave of CeltEuskarian emigrants towards the more organized regions. Irishmen have poured into London, Liverpool, Glasgow, and South Wales ; High- landers into Glasgow, Edinburgh, and Paisley ; Welshmen into. London, Birmingham, Liverpool, and Manchester. At the present day, as Professor Huxley remarks, the dark type seems once more to be numerically superseding the light one. Almost all of us are English in language, but most of us are only very partially English in blood. To put the same matter another way, our oldest element is the dark one, now scattered up and down tlirough the population, and only gathered very sparingly into a little nucleus here or there in Ireland and Scotland. This element was Celticised, V)ut not exterminated, by the Aryan Celts, and became with them the Celt-Euskarian "Ajicient Britons " of our history books. Then the Celt-Euskarian was conquered by the Teutonic Englisli, and Anglicised into the English of pre-Nornian times. Next, these mixed English were con- quered by Danes, whom they shortly absorbed. Dane and English were afterwards conquered by Normans, whom once more they absorbed. Dane and Irish in Ireland were next conquered and Anglicised by Norman-English, and the countrj' furtl)er settled at various times by English and Scotch. Lastly, all these elements have coalesced with Welsh, Highland Scotch, and Scandinavians of the Isles, to form one heterogeneous Britisli nation, so inextricably intermixed that its ethnology can now only be reconstructed in the rough. But all through, each earlier element has everywhere persisted in tho resulting mixture, and it is probable that the numerical proportion of all the older elements, especially tho Euskarian, is far greater tlian people generally at all imagine. WINNING WAGERS. By the Editor. IT is rather singular that any writer who points out the folly, or worse, of wagering, is nearly always supposed by a large section of his readers to have wagered a great deal, and to be ready to wager a great deal more. An article I wrote about lotteries for the Cornhill Magazine, immediately brought me several invitations from tlie Con- tinent and from America, to purchase tickets in sundry lotteries. Since I wrote about betting in Kxowledue, I have been asked (who have never wagered a shilling on a race) to give hints for wise wagering whereby fortune may be gained without the usual equivalent of work done. My attention has been directed to the success which book- makers have achieved, and I am asked to put the young and verdant sportsman on the track which lias led to so agreeable a goal. I am further reminded that it is all nonsense for me to assert that betting and gambling must end badly in the long run, for if so much money is lost, much money must be won. " Why may not I," for instance, asks one, "be a successful votary of fortune, and ■win some of the money which you say is always lost by those who wager freely and often 1 " Well, not only is this so (I have known a young City clerk win £ 1 , ."lOO on the Derby, and regret it for years as the worst misfortune that had ever befallen him), but there are ways by which Fortune can be set on one side alto- gether, and money always won on a race, by anyone who, knowing how to proportion his wagers, can give time enough to the subject to get all the wagers made which the system requires. At the outset let me note that it is by no means neces- sary that the system I am about to describe should be carried out in a precise and formal manner. If you have a tolerably large capital, or if, in case of failure, you have courage (greatly daring) to run away, you may leave a little to chance on every race, and then, if chance favours you, your gains will be proportionately greater. The system is exceedingly simple ; and it will be found that when the method of the great bookmakers is analysed a little, there underlies it the fundamental idea of the system ; yet probably not one among them knows anything about it in detail, though he may thoroughly well under- stand that his method leaves very little to chance. First, always lay odds against horses, never back tliem. This is not essential to the system regarded in its scientific aspect ; but in practice, as will presently appear, it makes it easier to apply it. Lay against every horse in a race as early as possible, when the odds are longest If you lay against a few which are certain not to run, so much the better ; that is so much clear gain to start with. Proportion your wagers so that the sum of what you lay against a horse, and what he is backed for, may amount to at>out the same for each horse. The precise system requires that it should be exactly the same, but you will find tliat you can often improve upon the system by taking advantage, in special cases, of your own knowledge of a horse's cliance ami your opponent's inexperience. In every case lay odds a point or two short of the legitimate odds against a horse. Suppose for a moment that the odds are ten to one against him, then it will always be easy to find folk who rather fancy the horse, and think tho odds are not eight to one, or even si.x to one, against him ; select such persons for your wagers about that horse. Convey carefully the idea that you also think his chance underrated at eight, or even nine, to one ; but, as a favour, make the odds nine to one. KNOWLEDGE ♦ [Junk 2, Of course, you need not search about for those who favour any given horse. Every greenhorn has a fancy for some horse, and is willing to take something short of the current odds for the pri\-iloge of backing him. You can, therefore, till in j'our book pro re imfij, until at least you have made up your amounts for most of the horses engaged, when you will, of course, give more special attention to those whose loaf in your book is as yet incomplete. Now let us take an illustrative case to see how this system works :— Suppose there are nine horses in the race, to wit — A, n, C, D, E, F, G, H, and K. Let the odds be— 3 to 1 against A 5 to 1 „ B 7tol „ C 9 to 1 „ I) 11 to 1 „ E lltol „ F lltol „ G 19 to 1 „ U 23 to 1 „ K You should be careful to note that when these odds arc reduced to chances, becoming respectively their sum should be unity, or very near it. It does not matter at all — except to backers — if the sum is greater tlian unity, as it generally is, but if it should be less than unity, the e.xact application of the system would invoho loss to you and gain to the backers, which is not your object) Well, then, you may let the wagers on each horso amount to £1,000 (or, for convenience, and to avoid frac- tions, say £l,-200), if the race is important, and bets much ill recjuest ; but the system, in its beautiful adaptibility, may be applied to .shillings quite as well as to pounds. Apart from the c.\.tra points you allow yourself, you ought to lay, in all — £900 to £300 against A £1,000 to £:i00 „ B .i:l,<50to£l50 „ C tl.OSOto£120 „ D £1,0S0to,C120 „ E i-l,100to £100 „ V £1.100 to £100 „ r; £1,140 to £G0 „ II £1,150 to £50 „ l-C But you rea-son (with intending backers) that "the race is a moral certainty for A., and that it is giving away money " to lay more than (in all) ,£800 to ,£:500, Again, " li. is a much better horso than people think, so that £900 to £200 is quite long enough odds again,st him' ; " as for C, "no wonder backers stand by him at the odds;" for your part you "think him better than B, ; and see what Augur says of him ! " and ,so forth, wlierefore you cannot lind it in conscience to lay more than £9.")0 to £1.50 (in all) again.st hira, (It gets easier as you reach the non- fa%-ouritcs to get the odds shortened.) So you deal with each, cutting off £100 (let us say); but with the horses low in favour, you can easily cut off more, and the system not only does not forbid this, but encourages it. Say, however, only .£100, and then your book is complete. You can now watch the race (if you like) with thorough enjoyment The pleasure of the backers of the favour- ites w a good deal impaired by anxiety, and though backers of non-favourites Iiave less tf) lose, they have more to gain and less chance of gaining it : so they too are anxious. But you can take a real scientific interest in the race. Vou may, if you please, try to recognise Muyliridge's •' Attitudes of the Galloping Horse," as the fleet steeds rush past your post of observation. For, let the race go as it may, you clear ,£ 1 00. If A wins, you pay his backers willingly £800, receiving £200 from the backers of B, .£150 from those of 0, and so on — in all, £900. If B wins, you pay his backers £900, and receive from the backers of A, C, D, itc, £1,000, and so on, whichever horse may win. You need not, as a rule, be afraid about being paid ; these are debts of honour, and to be paid therefore before all sordid trade debts — nay, so sacred are these debts, that many of your clients would deem it better to break open a till, or to embezzle a round sum from an employer, than to leave them unpaid. So that you need be under no anxiety. It occurs to me that some of my betting readers may say. We have not time for this ; we do not want to be bookmakers, but to make our occasional wagers on safe lines, as t/n'i/ do their systematic ones. In that case, you might back each horse in the race once, so that the total wagered about him by you and the bookmakers may be a fixed Kiini, less whatever you can get off the market odds. l''()rinst.iiicc, say the sum is to be £120, in the case of each lior.se in the above list ; then you should back A at the odds of £90 to whatever sum less than £30 a bookmaker will take. Suppose (I cannot suppose it myself, but you may) he will give you £90 to £29 ; and that you can arrange similarly for each horse of the nine, offering to l)ack him for a sum always £1 short of the true amount at the odds. Then you will gain £1, however the race may end. It is not much, — but I wish you may get it It is easier to tell you how to lose. This may bo effected by adopting (lie ol/ifr j^rt of the bookmaker's system. He, always lays the odds a little short : do you always take them so. Back the favourite boldly ; l)ut do not fail to take fancies for non-favourites, and liack your fancies boldly too. It would be absurd to haggle about odds in the case of a horse which is morally sure to win, or to insist on ten to one when you feel sure the odds are not seven to one against a horse. When you win, assure yourself you are "in the vein," and go on betting ; if you lose, assure your- self " the luck mu.st change," and go on betting. By con- tinuing patiently on this course, it will bo strange if you do not learn before long — how it is that the bookmakers make so much money. Let mo, in conclusion, quote two short passages, one from a letter by Charles Dickens, the otlier from a speech by Lord Chief Justice Cockburn, The lirst seems to relate to the successful book-maker — " I look at the back of his b.ad head repeated in long lines on the racecourse, and iu the lietting stand, and outside the betting rooms, and I vow to God I can see nothing in it but cruelty, covetousness, calculation, insensibility, and low wickedness If a boy with any good in him, but with a dawning pro- pensity to sporting and betting, were but brought here soon enough, it would cure him." The other passage applies to the bookmaker and his victim alike — "the per- nicious and fatal habit " of betting "is so demoralising and degrading, that, like some foul leprosy, it will eat away the conscience until a man comes to think that it is his duty to himself to " do his neighbour as his neighbour would do " him. FOUND LINKS. By Dr. Anbrew Wilson, F.R.S.b:., F.L.S. PART VII, A CORRESPONDENT, " J, Fisher, M,D.," in a letter addressed to the Editor of Knowledok, remarks that the names " Quadrupeds " and " Mammals," used Ijy me as synonymous terms, and, I may add, in strict JcNE 2, 1882.] • KNOWI.EDGE accordance with natural history usage, are apt to convey what he is pleased to call an " erroneous impression." He remarks that the whale is a " Mammal," but not a "Quadruped" — meaning, of course, that a whale has not four legs. Dr. Fisher may, perhaps, have heard the remark tliat a good deal in this world depends upon one's point of view ; and his point of view happens in this case not to be mine. I carefully explained that I used the terms " Quadruped " and " Mammal " as convertible names, and this for the reason that in zoology — as, indeed, in every-ciay life — the names are so em- ployed. Has Dr. Fisher ever heard of a frog (one of his examples) Vieing called a " Quadruped," in the same breath with an ox- And does he not know that a whale possesses all the essential characters of quadruped- life which he himself rejoices in the possession of ? As to a whale not possessing four limbs, perhaps Dr. Fisher, not being a zoologist, is not aware that in some whales {i-.g., the whalebone genus, or Bahma) there are actual representatives, not merely of the haunch- bones, but of the thighs as well. Hence, a whale may claim to be a quadruped, even although its hind-Umbs are rudimentary. Dr. Fishers somewhat querulous objections are overruled by the fact, that, as I started by defining " Quadrupeds " and " Mammals " as being one and the same, the scientific meaning (and, as I maintain, the popular raeaning also) of these terms is not likely to Vie mistaken liy any reader of ordinary intelligence. It is true, as Dr. Fisher remarks, that in many mammals, the clavicles, or collar-bones, are wanting, just as these bones are absent in some members of an order (e.g., rcdents) and present in others : or, as is the case with the guinea-pigs and rabbits, the clavicles may be wanting at birth, and become developed later. What I indicated in my paper (Knowledge, No. 2.5) was the typical condition of the quadruped shoulder. If Dr. Fisher maintains that it is more typical for a quadruped to want collar-bones than to possess them, that is his affair. He is not likely to find any comparative anatomist to agree with him. In the present paper I purpose to give an outline of the means wliereby the zoologist has been enabled to supply " links " between the Vfrtebratr, or " backboned " animals, and the Inverfebrati:, or "boneless" animals. Ever since the time of Lamarck, the distinction between the highest, or Vertebrated animals (fishes, frogs, reptiles, birds, and mammals or quadrupeds) and the Invertebrate groups, has been recognised as one of very clear nature. And modern zoologj-, dealing merely with the structure of the animals in question, fully recognises the apparent gap which inter- venes between the great array of boneless animals — such as -worms, insects, shell-fish, itc. — and the " backboned " group. But, as in many other cases, a closer examination of the lowest Vertebrate group seems to demonstrate that the gulf between the highest animals and their Invertebrate neighbours is by no means so wide or impassalile as, at first sight, it appears to be. The lowest fish and Vertebrate is the Ani/'/iioxus, or Lancelet (Fig. 1). Tliis is a little clear- bodied fish — formerly regarded as a kind of slug — found inhabiting sand-banks in various quarters of the world. It attains a length of an inch or two, and is pointed at each end. It has a kind of back and tail tin, but possesses none of the " paired " fins, wliich, existent in most other fishes, represent the limbs of higher animals. The moutli {<•) is an oval slit, and is fringed with gristly fila- ments. The lancelet has no brain, heart, bones, skull, eai-s, or kidneys. It is the only vertebrate which wants a heart, and it is likewise the only vertebrate in which the blood is colourless. Along the back runs the only representative of the skeleton — namely, a soft rod-like body, called the notochord (n). This structure, by the way, is found in the early development of every vertebrate animal, being re- placed in all, save a few fishes, as time passes, by the spine itself. Above this rod lies the nervous cord of the lancelet. The mouth opens into a very wide throat or j/hari/n.r (b), whose walls are perforated with slits that open into the cavity of the body. The walls of this great throat are richly set with the microscopic processes called cilia, which, by their incessant waving, circulate the water admitted to the cavity. The throat leads into a simple stomach (g), and Fig. 1. — The Lancelet (Amphiozus laneeolatus), enlarged to twice its natural size, (o Month ; i> Enlarged pharynx ; <7 Stomach ; ■h Sac representing the liver ; » Intestine; a Anus; n Notochord ; / Eudiments of tin-rays ; p Abdominal pore). this, in turn, leads into the intestine (;). A liver (/<) of the most rudimentary description also exists. The blood, in the absence of a heart, is circulated by the contractions of the bloodvessels, and it is interesting to note that the arrange- ment seen in all vertebrates, whereby a portion of the venous, or impure blood, is sent to the liver for the manu- facture of bile, is represented even in this curious fish. When the lancelet breathes, v.-ater is received into the throat, passes over the network of bloodvessels in the walls thereof, and after giving up its oxjgen to the blood, is sent by the cUiary action through the slits in the throat into the body cavity. Thence it is expelled through a small opening near the tail, and called the abdominal pore (j)). The lancelet differs from every other vertebrate animal in the absence of a heart, skull, brain, and kidneys, and in the colourless blood : in tlie peculiar and rudimentary liver ; and in a digestive system, which, like the throat, is also lined with cilia. But that it is a vertebrate is proved by the presence of the notochord (»), already remarked as being developed in the early life of every vertebrate animal. The supply of venous blood to the liver is also a vertebrate character ; whilst its development, studied from the egg onwards, no less clearly shows its right and title to be regarded as a true vertebrate. HOME CURES FOR POISONS. ^TO one who is wise will fail to send at once for a doctor 1\ when poison has been taken, eitlier by inadvertence or otherwise. But there arc often remedies or antidot4'S close at hand, which may be of great use, even to the saving of life, if taken at once. It is not with any idea of encouraging people in such cases to do without the doctor, but to indicate certain home cures for even the most violent poisons, to which recourse can be had before he comes, that we write this series of short papers. There are cases in which the nature of a poison taken inadvertently can be determined at once, when therefore the proper home cure, if such there be, is at once known. Then' arc other cases in wliich, though it be not known what poison has been taken, tlie symptoms presently show at least the class of poisons to which the substance Iwlongs ; in many such cases the remedy is as certainly indicated as though the 8 ♦ KNOWLEDGE • [JUXE 2, precise nature of the poison were known. We shall con- sider cases of both kinds. But first, as Prevestiox is better than cure, we may ninind the reader that every substance, whether medicinal or otherwise — every drug or rhemical which has poisonous ijualities — should be not only properly labi'lled, but carefully kept out of harm's way, and where there are children, shoiild bo kept under lock and key. Better take precautions which seem unnecessary, thaji run risks which may be avoided. If people would treat a bottle of poison as they would (or rather as they s/ioiihl) treat a loaded fire-arm, we should less often hear of accidents about which, after they have taken place, the person who has really caused it can only say, " I never thought it could have happened." Arsenic. Arsenic has very little taste in the form in whieh it is usually known in commerce — viz., as white arsenic or arsenious acid, the white o.\ide of arsenic. For this reason, it is often used for criminal purposes. But fortunately, if it can be given easily, it can be detected as readily in the l>ody, not only when present in very minute quantities, but after many weeks and even months have elapsed from the time when the body was buried. The first symptoms noticed after arsenic has been swallowed are sickness and faintness, following generally within half-an-hour after the poison has been taken, but often much sooner. Then follow violent and spasmodic pains in the bowels (increased by pressure), attended by a ■burning feeling, dryness, heat and constriction of the mouth and throat, increased How of saliva, and an unquenchable thirst, itching of the face and neck, and palpitation of the heart, with full, hard, and freiiuent pulse. Vomiting and purging follow. Sometimes the skin is burning hot, at others icy cold and covered with clammy perspiration. The pulse sinks, becoming irregular and feeble. Then, if the poison has been given in sufficient quantity, convulsions *.-ome, and before long death cnsue.s. In certain rare in- stances the symptoms above described are scarcely observ- able, yet within a few hours the patient sinks ; in such cases the presence of arsenic is indicated by a lethargic sleep. In cases of slow poisoning by arsenic (which, how- ever, do not belong properly to our subject, since in their cast; the physician only can be of service) there is often no recognisable symptom, no inflammation, no fever, constipa- tion, or vomiting, but langour, weariness, and disgust for food, followed by torpidity of the nobler organs, especially the lungs — death coming as certainly, though not so swiftly, as when a single poisonous dose has been taken. The best home remedy for arsenical poisoning is a mustard emetic, but if sulphate of zinc can be oV)tained, an emetic formed of from ten to twenty grains in about a quarter of a tumbler of water, is better. For a mustard emetic, take a dessert-spoonful of flour of mustard in a. teacupful of warm (not hot) water. Large quantities of milk or warm water, or, better still, linseed-tea or barley- water, should l>e taken, to promotf; vomiting. Tickling the back of the throat with a feather, or with the fore- finger (if the patient has lieen accustomed to that way of producing vomiting) may be resorted to with advantage. Tlie patient should note, in all cases where the stomach is to Ix; cleared of its contents, that, while much is rejected after the throat has lieen tickled, it is well after a while to wait for the sort of after - throe which comes without sucli tickling, and seems to carry away a portion of the stomach's contents which is retained so long as the tickling is continued. It is better, however, to encourage vomiting rather by swallowing large quan- tities of the warm liquids above-named than by irritating the back of the throat. After the stomach has been cleared of its contents by the use of emetics, itc, lime-water, or chalk dissolved in water, should be swallowed in large quantities. Or, if none is at hand, mix a pound of soap in two quarts of water, and take a teacupful every five or si.x minutes. Failing either of these, powdered charcoal, if at hand, may be taken with advantage. It will be well for the patient, however, if, before this stage of the treatment, a doctor is at hand to take the case in charge. The after treatment requires all the doctor's care in serious cases ; for the above remedies are not, properly speaking, antidotes. THE AMATEUR ELECTRICIAN. OUR next task is to fix the inductor, A-c. To do this, take a piece of brass plate a quarter of an inch thick, twelve inches long, and shaped according to the dimensions given in Fig. 7, which is a plan of the plate. 1 f2 Inches. r ■ Fig. 7. minus the parts which are to be fixed to it. It is repre- sented in section by A B in Fig. 8. The lower pole-piece, E F (C, Fig. 6, Jlay r!G), is to be screwed on say at C C C, the heads of the screws being well sunk. P P' are two brass standards, or pillars, about two inches high, to sup- port the steel screws S S', which form the centres upoa which the armature will revolve. These standards should be ^•ery strong and firmly fixed*. They should be half an inch thick, and shaped (in a vertical plane at right angles to the axis), according to Fig. 9. This will tend to con- siderably increase the rigidity and durability of the machine. The centre-screws should, of cour.se, be fixed by means of check-nuts on each side of the standards. When all is done, the plate, AB, must be firmly screwed at available places (Fig. 8, G) to a .stout wooden base, of which, however, more will be said when speaking of the motive power next week. We have advised the use of centres, as opposed to bearings, to obtain the best results with the least expenditure of force, and because, further- G 1^-=^ more, of the small weight which luis to revolve. Where, however, a larger armature is used, or if even with the one described, a high velocity is attempted, bearings should be adopted ; otherwise, the wear and tear would be very great, and we should soon spoil our machine. As regards the commutator (Fig. 5, May 20), the one we are adopting is constructed on a principle which in- • It would be better, where it is poBsible, to have the plate and standards cast in one piece, the standards being 9 in. apart. June 1882.] KNOWLEDGE ♦ 9 volves a fractional loss of current, but, at the same time, it removes an element of danger. The ordinary commu- tator consists of a cylinder of metal cut crossways, and so dividing it into two parts. This, however, involves the short-circuiting of the armature for a lirief fraction of time twice during each revolution ; heat is in consequence pro- duced. We have preferred, therefore, to recommend a total disconnection of the circuit twice in each revolution. This may seem a great loss, but really it is very trifling. It also tends to keep the armature cool, and, above all, it has been found to answer well in the Brush dynamo- machine. We must, however, take care that our discon- nections are made at the right time. Our readers will recollect that in the introductory article we stated that a certain current was induced as one pole of a magnet was inserted in the coil, while the opposite current was induced by withdrawing the magnet. Similarly and conversely the approach of one pole, say the north, produces the same electrical effect as withdrawing the other or south pole. Referring once more to Fig. 6, we must regard the coil of wire as surrounding an ordinary soft iron core, whose ends (A. B., Fig. 1, May .ith) become north or south, according to the relative position of the armature. Let us for a moment Fig. 9. associate ourselves with one end or side of the core, and let the armature perform a quarter of a revolution, so that our end is uppermost As it starts revolving (say to the right) it gradually leaves the north pole of the magnetic system, and at the same time approaches the south pole. Going from the north and to the south, it is necessarily subjected to the same magnetic influence, accompanied by a similar etiVct on the coil of wire. At the moment that our end is crossing the vertical line, no current is produced. Of course, as the end ascends on the opposite side, passing from south to north, the opposite magnetic, and therefore electrical, effect is produced. We must, therefore, to get the best effect, so arrange our commutator that the " brushes " or " collectors " rest on the sniall insulated pieces of metal (C. D., Fig. .5), when the core is in the vertical i>lane. How shall we do this? Space compels us to defer the answer to this question till ne.xt week. Ekbatim.— In last week's article, page G19, second colnmn, line 19, read Tib. for 71b. THP] ECLIPSE. "IT'E have received the following interesting coinniunica- \> tion from Mr. A. C. Ranyard, who kindly under- took to forvvard communications to us respecting the eclipse. " Sohag, Upper Egypt, ".lAri/ 17, 1882. " 1 ain sorry that you were not able to come out to the eclipse. The weather has been all that could be desired, and the Corona magnificent, in a perfectly clear sky, with a bright comet within about half a degree of the moon's limb. The diflBculties have been very slight, and the trouble caused by heat and flies much less than we were led to e-xpect. We have lived in great comfort on Vioard a steamer anchored alongside our tents. The Khedive has entertained us at his personal expense, and has had pillars built for our instruments, besides giving us a guard of soldiers and water-carriers, who have perseveringly endeavoured to keep down the dust round our station by means of water carried up from the hill and distributed from goat skins. I had made every preparation to defend my instruments from the wind which frequently springs up during totality, but instead of a wind there was a dead calm. "The Ccrona'was of the sun-spot maximum type, with no very marked rifts. As seen in the telescope it was full of structure, delicate lines of light curving hither and thither, and arranged in great groups. There was one very marked, long, straight ray, and several structures like great promi- nences stretching to a height of 15 or 20 minutes. Tliese are shown in my photographs, as well as the comet, which has registered itself, together with about half a degree of its tail, on some of the plates. I did not succeed in obtaining a photograph of the spectrum of Young's reversing stratum, though the bright lines were well seen for about three- seconds. — Yours sincerely, A. 0. RANYARD.' BUTTERFLIES AND MOTHS. By W. J. H. Clabk. WE have now arrived at one of the busiest months of the year for the entomologist ; every bush and tree teems with insect life, and both butterflies and moths in the imago or perfect state, and larx-iv and pupe Alder (Acronijcta Alni), the Bramble (.4fr.iiiy.-((i Riimifi'*), Common Wainscot {Leucania Pallrnn), Bird's Wing (Diptenigia Pinagtri), Doubtful Nutmeg (Uaimstra Anceps), Cabbage Moth {ifamesira, Braissicce) , lYoblo Lines(Gr.immi;»i.i2'iiIiHea),DoubleS(iuareSpot(A"'oc(ua3Viaii<;itIum), Ac. These, and several others more or less scarce, aro to be obtainearnt together with the English, as genuine collectors invariably employ the former when speaking of a butterfly or moth, the advantage being that many insects have purely local names, and an entomologist from, say, the south of England, would find the same insect called by a very dif- ferent English name in the north country-, but tho Latin appella- tion is the same all over the world. A great many caterpillars are to be found this month on the trees and hedges, and next week we will give a short list of them, together with their haunts and food. If the lepidopterist comes across any in the course of his travels he would do well to box them together with a piece of the tree on which they are feeding, and breed them up. A hat-box with a piece of net stretched over the top acts as a fair elementary breeding-house, but next week wo will describe the manner of making a good one. Feed the eater- pillar once a-day with fresh leaves, but do not liandle them, as they are very delicately organised, and a slight squeeze might do them considerable injury. MASS AND WEIGHT OF THE BRAIN. IX his able treatise, entitled " An Introduction to Human Anatomy," Professor Turner, of the University of Edinburgh, writes thus on ''The Mass and Weight of tho Brain" : — The human brain is absolutely bigger and heavier than the brain of any animal, excepting the elephant and tlie larger whales. The brain of the elephant is said to weigh from 8 lb. to 10 lb., and that of a large finner whale between 5 lb. and 6 lb. The human brain is also heavier relatively to tho bulk and weight of the body than are the brains of the lower animals, except in some small birds and mammals. Considerable variations, however, exist in the size and weight of the human brain, not only in the different races of mankind, but in individuals of the same race and in the two sexes. The heaviest brains occur in the white races. The average weight of the adult European male brain is ■ICioz. to 50 oz. (about 3 lb.), that of the adult female 'Woz. to'ISoz.; BO that the brain of a man is, on the average, fully 10 per cent, heavier than that of a woman. Tlie greater wciglit of the brain in man, as compared with woman, is not in relation merely to his greater bulk, but is a fundamental sexual distinction ; for, whilst there is a difference of 10 percent, in the brain weiglit, the average stature of women is, according to Thurnam's calculations, only 8 per cent, less than that of men.* Or. Boyd states that the average weight of tho brain in tho newly-bom male infant is 11-67 oz. ; in the female only 10 oz. Tho exact a'/e at which the brain reaches its maximum sizo has been variously placed at from tho third to tho eighth year by different authors ; but it continues to increase in weight to 25, or '.iO, or even ■U). After CO the brain begins to diminish in weight ; in aged males the average weight is about 45 oz. ; in females about 41 oz. In some cases the adult brain considerably exceeds the average weight. The brains of several men distinguished for their intellec- tual attainments have been weighed. The brain of Cuvior weighed 01} oz. ; of Dr. Abcrcrombic, C3 oz. ; of Professor Goodsir, .57i oz. ; of .Spnrzheim, 55 oz. ; of .Sir J. Y. Simpson, 51-oz. ; of Agassiz, .'>3-4 oz. ; and of Dr. Chalmers, 53 oz. But high brain weights have been found where there was no evidence of great intellectual caf^acity. Peacock weighed four male brains, which ranged from [• If thi.i is so, tho brains of women aro more mussive relatively than those of men, for the weight varies, cmlerin •paribut, as the cubo of tho height, so that the weight of woman is less than that of man by 92 cnbed, as 778688 U less than 1,000,000, or by more than 22 per cent.— Ed.] 62-75 oz. to 61 oz.; Boyd, a specimen of eO-7r)or ; and T have in my possession ono of a boy, aged \^. v, ! irli •■ ■■ ! il ''•" (v Tn tho brains of the insane, high brain w^i ! : ' ^ ' rvod. Bucknill met withabrain in aniali' 1 I I I > i illuz. ,• Thurnam one which weighed G2 oz. ; aii.l M \\. I I, iiliM Asylum, out of 375 males examined, the weii^lit ul I lie liiain iii au cases was 55 oz. or upwards, and tlie highest weights were 6 1 oz . in a case of senile dementia, 60i oz. in a case of dementia, and 00 in a case of melan- cholia. No ease has as yet been recorded of the weight of the brain in a woman of great intellectual uttainnients ; but Boyd met with a woman's brain as high us 5525 oz., and many instances of upwards of 50 oz. in women where there was no evidence of high mental endowment. Skae, in a female monomaniac, observed a brain which weighed 61i oz. ; and of 300 females examined in the West Hiding Asylum, tho weiglit of tho brain in 26 cases was 50 oz. or upwards, tho highest weights being 56 oz. and 55 oz. in two cases of mania. The size and weight of the brain do not, therefore, per so, givo an exact method of estimating the intellectual power of the indi- vidual, and a high brain weight and great intoUeetual capacity aro not necessarily correlated with each other. TOO MUCH BRAIN-WORK. " r\^ April 28, Dr. l{i.;hardson, F.H.S., delivering a lecture on \J ' National Necessities as the Bases of Natui-.il Education,' before the Society of Arts, brought forward," writes P.C.S., "tho following extract, which hajipenod to lie a report of the Chairman of the evening, Mr. Edwin Chadwick, CIS., to the British Associa- tion in 186n, to show what an evil otTect too much brain-work, without a prnpnrtiniinl nTiionnt of industrial occupation to support it, has 11)1011 \niiiiL' .Iiillivii. I givo the extract vorhatim,a.a it bears closely (ill a |iciini i-.i-nitly under discussion : — " In oni' lar-r isiaMisliiaent, "containing about .<.i\- liiuulrod chil- droii, half -iris ami half boys, tho means of i-pln liiil .irnipation wc-ip f.'aiiH'd fur tlu' t;irLs before any were nlii ii- I i.i lioys. 'Chr ;.'irls wci-c tlicivfon^ lint upon half-time I in: msay, llieir (iino of book-in.Htnictioii was reduced iiMin iniiy i. hours to eighteen per week, given on tho three altcrnalu days of tlieir in- dustrial occupation, tho boys remaining at full school time of thirty- six houi-s per week, the teaching being the same, on tho same system, and by the same teaelieis, the same school attendance in weeks and years in both cases. On the periodica! examination of the school, surprise was expressed by the inspectors at finding how much more alert, mentally, tho girls were than tho boys, and in advance in book attainments. Subserpiently, industrial occupation was found for the boys, when their time of book instruction was reduced from thirty-six hours a week to eigliteen ; and after a while, the boys were proved, upon examination, to have obtained their previous relative position, which was in advance of the girls." BRAIN TROUBLES. IlIAVE carefully read " Brain Troubles," and have met with many changes which might seem alarming to one who knows not the influence of digestion on the mind. The cases I am now going to give aro due to indigestion or some irritation of the stomach on the controlling powers of tho brain. After a heavy meal, especially after a heavy breakfast, 1 find some of my patients cannot write proper English. They say they can express their thoughts, but not in proper style. Other times they cannot express them at all. If they try to do so, they find they have forgotten half of their subject. If they continui; to write in spite of this, they i-uii words into each other. Thus, in writing " other rogues," they put down " other oguee," and often drop a word out of the sentence. Sometimes they mis-spell a word, know that it is wrongly spelt, and yet cannot find out tho mistake, unless they consult a "dictionary. The same in adding up a sum, or multi]jlying ; when they come to prove a sum they find it wrong, yet cannot find out where the iniHtiike is for a time. They may change letters in different words, thus in writing " good boy" they may put down "goob doy." Tliere aro other little things which an observer may notice, and which aro not signs of brain troubles, but of indigestion, or of some improper material in tho blood giving rise to these symptoms. These are not usually seen before a meal, or after a light on('. Again, irritaljility of temper most often means indigestion, or too full bloodvessels. Whenever I feel vexed at any trifling annoyance, 1 know I am suffering from too much food. I go for a walk or take some exercise, and so got rid of my spleen ! I hope this may bo taken in its true light, and not as a criticism on "Brain Troubles." T. R. Allinson, L.R.C.P., &c. June 2, 1882.] KNOWLEDGE 11 ^^: JilJia sl.^j': i":! i'[I S oS.2 J u C.-5 ,' "tj g '"' ^ _^ ^ >>£ i M o a !o I— I -£ *3 -^ -j: _ o £ „» g g .« <" O (3 O „;| ^ c- - S "^ "^ 5 — a'-^ •= a 1 -s s ^ "■ "° ^- := xc ^ ""^ — 5 i-" ^' — "> X ^ ■£ '^ •S 5 ji S 'x « r^ , ELS S ♦ KNOWLEDGE [JUXE 2, Irttrrg to tbf editor. '' 7^# SJHor Joft not 4o Si eitmmot unttfrtakt to r ,ortk*wrHfr',m„inim^.^ ■fvond ritk tneir irnV#r«. tly wia full and cUar » All Semittamcea, Ckecuts, and Poft-OMc* Order* 4- Son 'k* Editor w^ll be Xumbered. For convenience of refer r^erring to ang Utter, Ktii oblige by Mentioning it* nn Ati Letter* or Querie* to the Editor tchieh require attention in the current i»»ue oj :50iri.iDGB, thonld reock tht Futlishing OJice not Uter tkan the Saturday preceding i* daif ^publication. _ mnst be concise; they must be drawn that Ihev may ro untouched »o the Qununi cations, therefore, as well as' queries, or repHes to ppear as such) should be written on $i»par»te leaves. (either because too iong, or unBuitable, or dealing with have discussed, or for any other reaj^on) cannot find place ther be briefly referred to in answersto correspondents, or acknowledged reeerred (or the purpose. lan only ti to be contemned and de(:pi«ed who ie not in t . . Hot is there anything more adverse to accuracy Farad ajf. ■pa niistalte^ but preat harm pnotert ; private queries (iiktended (II.) Letters which "In knowledge, th state of tr«ni«ition. than fixity of opinion •'There is no harm ^ „ ^., me a man who make* no miatakee, and I will nothing."— itVfci.7. •* God's Orthodoxy is Truth."— CSar/« Kingsley. 0vix Corrrsponbnuf Columns. MACAn.AY (IN SMAI.L-roX. [414] — As an addciidnm to what Macaulay says (as quoted in jour edition of Saturday last), in respect of the'prevalence of small-pox 2(0 years afc'o, permit me to call your attention to his opinion as to the value of vaccination as a preventive. " In spite of these elotiucnt eulogies (on the introduction of Hcming's lamps for the purpose of lighting the streets of London) the cause of darkness was not left undefended. There were fools in that af,'o who opposed the introduction of what was called the new li^rht, as strenuously as fools in our age have opposed the intro- duction of vaccination and railroads ; us strenuously as the fools of an npe anterior to the dawn of history doubtless opposed the intro- duction of the plough and of alphabetical writing." As showing the intensity and prevalence of the disease at that time, I may parenthetically mention that three of the leading characters of that reign Buffered most severely, viz., William, Mary, and Bcntinck ; Mary dying of it. Direct and positive evidence of the terrible nature of a visitation of small-pox on a population entirely (or nearly so) unprotected by vaccination, is afforded by the accounts which reach us of the out- break now raging in the Island of Hayti (reported in the Jiriliah ilt'lical Journal a week or two since), "when the nnmber of deaths during this single outbreak, and amongst a sparse population, is calculated at no less than 20,000 victims. Obsekver. A MISPLACED SPA. [415] — Most people must have noticed that new brick buildings are often defaced by a white incrustation which disappears in damp weather and reappears in sunshine, and often obstinately continues to do so, on parts of buildings sheltered from rain, even after the structure is no longer new. An example may be seen in a hand- some Wesleyan church in the Anerley-road, near Anerley station, and in new houses and walls about Red Hill, and at Thornton Heath, near Bcnlah Spa; and in what other localities is a question dewrving investigation. f)n asking the cause of this from workmen, foremen, bnilders, and even from a local architect, I have received the various answers that it was lime, saltpetre, and that sea salt had been used in the mortar ; only yesterday, I was told confidently, " that, sir. is the chalk drying out." It is curious that so remediable an nnslghtlinesa has not been letter examined by these experts, for it is Glauber's salt, an>l therefore easily removable. At the ffKit of the Surrey Highlands, where the Dorking and Rcigatc sand begins, east of Kcigate, to diverge from the chalk, and to give place, between it and the chalk, to n ba.sin of blue clay, and in the cellar of a house which I inhabited at tiatton I'oint, I found esuiliiig from a wall built against the clay, crops of long feathery crystals, which I thought at first were some kind of vegetable mould. These constantly reappearing, I gathered in a gallipot, li.\iviated, strained, and found to be jiurc sulphate of soda. I have no doubt the deposit continues still. People there sometimes complained that the well-water had an aperient effect. I gathered the salt at the brickfields, and on tlie then newly-built Gatton-park wall, and it appeared concentrated in the water in which they jiuddled tlio clay. There are fuller's earth quarries at Nuttield, in the locality j but I believe the soda in fuller's earth is not in the form of sulphate. I thought at first the sulphur might como from the breeze with which the bricks are burnt J but the deposit in the cellar camo from unburnt clay. There must bo hundreds of tons of it in these clay beds ; and, in certain bricks, it appeared to me to be in sufficient quantity to pay for soaking the bricks. Whether the valley surrounding the high Would uf Sussex was anciently invaded by high tides, and this is iilti red sea salt — how altered ? — or whether it is a frosli-water (lipcisit, may bo questions having some interest; but it would evidently be of immediate advantage to scrub this misplaced aperient from handsome buildings. CURIOSITV. TIMBRE OF TRUMPET, ETC. [41G]— Can any of your readers tell me how the difference of tone in the trumpet and cornet is to be accounted for ? I have looked into all the books on physics and music I kaow of, but this link between the science and art is wanting. Is the finer tono of the trumpet due to the fact that it has a greater length of tube for the same pitch (as it seems to me to have) ? If so, I suppose that trumpet and cornet have much the same relation to each other as grand and cottage piano have. Or, does the tone of the instrument depend on the number and form of the bends in the tube ? If so, how is the greater difficulty in playing the trumpet to bo accounted for? In the horn, trombone, bombardon, i-c, I notice that the tube gradually increases in width from a point near the mouthpiece to the bell (the ratio of increase varying in the different instruments). With this exception, these instruments seem to be exactly similar in form to the trumpet and some forms of cornet, and this makes me think that the number and form of the bends in the tube cannot appreciablj- affect the tono. Information and correction on any of these points will greatly oblige, 1'. E. Swinstead. POPULATION OF TllK KAKTH. [417]— Adverting to your article, " I'oinil.ntion of the Earth," p. 584, Kxowi.EiiGE, may I be permitted to remark that it suggests a lesson which all moralists and philanthropists may well take to iie.art. You show that had mankind during the past -1,000 years been as free from the decimating influences of disease, war, Ac, as. during the past year England lias been, the human race then had been in number sufficient to throng the surface of a globe having a diameter 5,000 times that of (ho earth's. Whereas, it is highly probable that the actual number of persons who have existed during this period could stand on a plain in extent less than 70 miles long and CO miles wide. That is, if we may reckon an average population nf 750,000,000, and 160 generations of 25 years each. Tl:us— 750,000,000 average population. ICO generations. 120,000,000,000 total population. =4,000 square miles. 30,000,000 to a square mile. But, even taking the present population of 1,. 100,000,000 as the average, and calculating for G,00(l years, then it would appear that the whole human family— all who have had an existence [in that time] — could stand on a plain 150 miles long and 80 miles wide, or little more than the surface of the Principality of Wales. Thus— 1,500,000,000 average pojiulation. 240 generations. 360,000,000,000 12,000 square mile! 80 miles.— A. WoOD. FovD'B F.XTBACT is A Certain care for KbcumMttum and Oout. Pond'* Eitract is a certain cure for H(rmorrhoidi«. Pond'a Extract in a certain cure for Ncural^c pains. Pond-. Eitract will heal Hum« and Woundfi. Pond's Eitract will cure Sprains and liroisea. Bold t.r all C I Chemjets. Get the Ja 1882.J KNOWLEDGE 13 anstong til Corrrsfponlifntsf. *^JU cmmmteiiUons for ilu Editor requiring early attention ihould reach the Oj!t» on or before the Saturdof preceding He current iuue of Kxcwtssei, the i0i:rta*ing circulation of which eompele us to go to preet early in the veek. HlXTS TO CoHBBSPOXDE^rrs. — 1. Xo qneftiona atking for tcientijic information can be anrieered through the post. 1. Lettera went to the Editor for correepondente ctinnot be forwarded ; nor can the name* or addreeeet of correepondente be gicen in answer to private inquiries. 3. Correspondents should write on one ride only of the paper J and put dratcings on a separate leaj. 4. Each letter should hare a title, and in replying to a letter, r^erence should be made to Us number, the page on which it appears, and its title, J. Haetixgtox. You consider that with our present circulation (»Thich yon under-rate, by-the-way, for our first volume Iiaa reached niany more than the 20,000 you mention) we oufrht not to think of increasing oar price. We do not think of so doin^. But we think it probable you form inadequate ideas of the relation between the expenses and the returns of such a journal as this. You speak of 20,000 twopences ; at trade rates 20,000 pence would be very much nearer the mark. These are sordid considerations, are they not ? why, certainly ; and the thought of daily mejOs is an animal thought, is it not ? Try raising your sonl entirely above this animal thought for a week or two, and then give us your ideas about Knowledge. — UxiT.ts. Yes; the vibrating periods of the different rays of the spectrum have been accurately determined. . The information will be found in any treatise on the spectrum. There are 458 billions of undulations per second in the extreme red, 727 billions in the extreme violet. — Xemo. Those stories of marvellons eyesight have often been found to be untrue. I should imagine Brussels paper of 1875 or 1876, from which you send an extract, appeared in the great gooseberry season. Let telescopists judge:— It tells us that Jean Trubell could see the four moons of Jupiter and the two rings of .Saturn. Not a true bill, yon may be sure. — J. Gottfried. The Magic Square, combined with the Knight's Tour, is good in its way ; but we cannot find room for it. We want a plan for getting a quart into a pint pot ; it always beats us. — Simplex. Slany thanks. — W. W. Fah-cus. Your theory of lightning hardly consistent with the production of the electric spark in perfectly dry air. — G. B. Fraseb. I ought long since to have thanked you for the very interesting book by Mr. Lindsay, which you have kindly lent me. It is full of matter of great value to me. — J. S. J. Thanks for note on change of colour of hair in case of one of the surrivors of Isandula. — Thoughtful. Will find space if possible.— Corbeau. Yes; La Fontaine's familmr fable makes the crow act rather foolishly. In Chaucer's Xun's Priest's Tale, it is Chanticleer who is beguiled by Keynard's flattery, and then Beynard is beguiled in turn. But this itj a lesson in sense, not in scienjo, — to show us What it is for to be reekelcss. And negligent, and trust on Battery ; and also that he is Indiscreet of govei'nance, That jangleth when that ho should hold his peace. .^I'^sop's fable of the "Crow and the Pitcher" might be used the other way, if fables counted. — Euclid. Thanks for account of fire- ball on May 4 at 9.30 p ni. If the same object was seen by others tar away from your station (Bolton), and a good account of the apparent pith can be given, the observation may be useful in determining the real path of the meteor in our air; otherwise not. — Jas. S3IITII. There is no rigid arch, and practically no arch at all, the curvature of the earth's superficial strata being so slight. If the Uim.tlayas were twenty niiles high there would be some reason for wondering at their stability. To all intents and purposes the pressures existing within the earth are such as would result if the whole earth were fluid. The cohesion even of a granite stratum, of whatever thickness, small or great, does not prevent the whole stratum from ]iressing downwards, and communicating downwards the pressure it receives from above, with practically unchanged effect. Sir W. Thomson's argument is, in fact, just this, that there is no solid shell with fluid nucleus relieved by rigidity of such shell from external pressure, but that the earth's whole globe is continuous, with no freed fluid mass within. If yon consider that, were the whole earth water, an ice mountain of any height (con- sistent with the rigidity of ice) could rear itself above that fluid surface, sustained by fluid pressures alone, you will see how little force there is in the argument you derive from the llimalaya.s. E. S. IxsULL, points out that in the Pharmacy Act, 18GS, prepara- tions of morphine, as well as opium and all preparations of opium are specifically mentioned as poisons. — F. "T. Jones. We would print your thoughtfully-nTitten letter in full, were there space : but there it not. The answer to your difficulty is simply, that within the period covered by astronomical observation the day has altered 80 slightly that, until quite recently, it was regarded as conatont ; the slight change would not affect the appreciably unchanging length of the year. You refer, I notice, to what I have stated as the result of the investigations of others as if it were my own sijecial statement. — J. U.vbgbeave. You ask in wliat sense the wordM "moment of gravitation" as used by Dr. Siemens in his letter are incorrect. In this — the word " moment," in all mechanical ques- tions, means motion, not the force causing motion; Dr. Siemens ajjplies it to mean the moving force on a mass of gaseous matter at the solar poles ; a moving force is measured by the " momentum " or '• moment," or quantity of motion it can generate, but to the mathematician, calling a moving force moment is as incorrect as it would be to call a printing-machine a printed volume.— Some More Fellows. Why, certainly ; so I supposed. — A. Jo.VES. — To deal with your problem, we must know the co- efficient of elasticity between billiard-ball and cushion, and co- efficient of friction between ball and baize. — Electbo.v. Others think a great deal too much space given to that subject. — E. L. H. Letter duly received, and shall appear. — E. M. O. Nay, but the transit will soon be over. Comets come and go all the time. — H. A. B. Sheet lightning is quite distinct from forked; the elec- tricity is of small tension, and there is no thunder. A flash of lightning being a discharge between cloud and earth, or between cloud and cloud, can never be said to be dispersed in air. — F. T. PiGGOTT. Paper on Foresights in type; thanks. Ale.x. Smith. Surely a note to Mr. D. Bogue, publisher of the now defunct Papular Science Review, would bring you what you require. — Peccavi. Peccaristi — in this respect, that the ink you have used has become so smeared that I cannot read all your questions. (1) A ray of light appears to travel onwards without measurable diminution within measurabledistances. (2) Do not knowexperimentally whether ascending air bubble in water casts a shadow, though rarer than the water. Theoretically it should, as a light ray will not pass out of water into air at small angles. (3) Stanley's book on Fluids, reviewed in K.nowledce a few weeks back, will help you as to the other ques- tions, so far as I can guess their purport from the few nnobliterated words. — F. W. Cory, F.M.S. I trj- a new arrangement for weather this week. You say, in passing, that many readers probably " usurp an Englishman's prerogative of grumbling — very often at nothing." I would not mind that so much ; what troubles me is, that some will grumble at evcr^-thing. This does not apply to your letter, though you do describe the weather reports as " simply abominable." I think you are about right ; hence the change. Possibly, «-ith the first number of Yolume II., which opens in June, an improvement on this may bo tried. Of course, there are many difficulties. — R. M. Hands. The passage in the Pvramid points too far from the Pole to aim at our present Pole Star, which is much nearer the Pole than Alpha Draconis ever was or ever could be. — 3oVD Mos-<. Are yon not thinking of a screw nearly " home," and overlooking the fact that Sir E. Beckett's device is to help chiefly when the screw is " far from home ? " He is no theoriser about such matters, bnt eminently I>ractical. lam sorry I overlooked your astrononiical query. Will you kindly repeat it ? — A. J. I. Thanks for story of omnibus horse stopping when lady hailed unobser\-ant conductor, "it certainly suggests intelli- gence and observation. — S. S. An intra-mercurial pl.inct, if such exists, must bo very much smaller than Mercury, and being farther off when in transit, would seem smaller still. It can readily Iw shown that the largest intra-mercurial planet which can exist con- sistently with the obser\-od constant absence of any naked-eye object "during total eclipses, must be utterly invisible when in transit (to unaided eyesight). — E. (!. I do not know of any com- plete tables of logarithms giving remits to ten or twelve digits. — Thomas Lvox.-i. Pray do not think us uncourteons in omitting your querj- ; it is quite true that the term "knowledge" is very wide, but the journal Knowledcf. is not very large, and something has to give wav when an attempt is made to make the less enclose the greater. " Five of Clubs " and " Mephisto " mil be proud of your favourable opinion of their colnmns.— Sheffield. Thanks for your kindly letter. Wo feel that, as yo\i say, it would l>o unfair to make n change in the direction of "enlargement with increased price." — Selexiai.. The keepers of second-hand Ixwk-stalls would bo able to tell you where to get old copies of the examination questions for matriculation at London. I do not know.— Fusiyama. .\1b', our renders " will not away with " more magic squares ! How can your lotus-leaf problem bo" donit with, without some data na to lotus- leaves :■ — J. I.ITHER Hayxes. I do not know in what paper you could get weekly information of the rainfall in Snrthe and Loin?.— J. F. Description of microphone in hand, as pnimised ; but wiint of space troubles us at present. " Eloctnm " and others wont more clectricitv, and scarcely any n.sf ronomy ; "J. Hemming " and others howl ngninst " Blow-pipe Chemistry," ond want more natural histor^•; and soon all down the scientific subjwts.— J. Gbo,>.vexo« Dawk! An index to Vol. I. will be issued immediately. [.Vboiit two pages of "Answers" hare been unavoidably held ever ] 14 KNOWLEDGE • [June 2, 1882. (!5ui- iirlatljcmatiral Column. INVERSE PROBABILITIES. THE formulas we have obtained sliow that in a set of ilrawings or trials of any sort sonic results are more probable than others. For instance, if we took a set of twelve balls out of a bag of l.liOO.OOO balls, of four colours equally divided, we should bo more likely to draw three of each kind contained in the bag, than to draw one of one specified kind, two of another kind, also specified, four of another specified kind, and five of the remaining class, but less likely to draw three of each kind, than one of one kind, two of another, four of another, and five of the remaining class, without specilieation.* And so in a variety of cases we can compare the chances of different results when the antecedent conditions arc known. But it is clear that this power of partial forecasting implies a power of inferring antecedent conditions from observed results. We may now enter upon this interesting department of our subject. In so doing, we are preparing to discuss that application of the laws of probability which is chiefly to be considered in discussing the result.'! of observation and experiment. But it is well to promise that the two departments of the science of probability are most intimately associated together, insomuch that one cannot well bo studied without the other. This will appear, indeed, at tlio very beginning of our discussion of indirect probabilities. We know from the laws of direct probability that if there aro in a bag ten balls, three white and seven black, the chance of drawing awbiteballis j^ , and the chance of drawing a black ball is j^- Xow if we suppose the ten balls all alike in colour (say all white), but three of them bearing a mark not discernible by tlio drawer (who, however, is supposed to be aware that three are marked) it is clear that when he has drawn a ball, although ho cannot tell whether it is one of the three marked balls, he knows that the probability of his having drawn a marked ball is 10- suppose these ten balls put into a bag with twelve others, these others being black; and that a white ball is drawn. In this case, as in the former, the drawer knows that the probability of 3 the white ball being one of the marked three is j^. The addition of the twelve black balls diminishes the chance of drawing one of the marked three, but when the fact is known that a white ball has been drawn, the chance that this ball is one of tlie marked three is obviously not a whit affected by the addition of the black balls. Xow, suppose that instead of twenty-two balls in one bag there are two bags, each containing eleven balls — in one bag the three marked white balls and eight black ones ; in the other seven white and four black balls. If a bag is to bo selected at random and a ball to be drawn at random from the bag thus selected, it will be obvious that the chance of drawing one of the marked balls is pre- cisely the same in this case as in the former ; for the chance of selec'ting the right bag of eleven balls is precisely the same as the chance that one of the eleven balls now in the bag would be drawn from lie original twenty-two, that is, is one-half. Otherwise, the chance of drawing a marked ball ivould bo affected by separating the twenty-two balls into two sets. For inst ancc, if the three marked balls were put into one bag, and the remaining nineteen into another, it ii clear that the chance of drawing one of the marked balls would 3 be one-half instead of 55. But the two bags containing the same namber of balls,t the chance of drawing one of the marked balls is nnchanged. Bat we have seen that when a white ball has been drawn from • As examples remove much of the seeming mystery of general laws, I will comparr; thcRC three chances together. The chance of any particular result is the same appreciably as though a ball were drawn at random and returned, the operation being repeated twelve times ; and this chance, ag:iin, is exactly the same as though the bag contained only 1 red, 1 white, 1 black, and 1 green ball. So that the p, ' three white balls, the other • balls, then if a bag is solecto 1 from this bag is white, the pi i white balls was selected i for distinguishing certain of I'm riiso where tho balls are ; I ills aro in effect distin- ' iliatwe need no longer I (lie conclusion we havo . 1 laining eight black and lull liliick and seven white "I ;i ball taken at random hill llio bag containing three 10 And by following the method whereby this special result was obtained, it is easily seen that the following general law can be deduced : — If there are in each of two bags p balls in all, q of the balls in one bag being white, and r of those in the other j then if a bag is selected at random and a ball drawn at random from this bag is white, the probability that the bag containing (j white balls was selected is — - — Of course, the probability that the other bag r + q was selected is It will bo observed that p does not appear in either result. Now take tho case where tho bags do not contain the same number of balls. Suppose one bag contains eight balls, throe of which aro white and five black, and the other tvrelve balls, seven of which are white and five black ; and supposing a white ball drawn, let us inquire what is tho probability that it came from the former bag? Hero wo can obviously reduce the problem to tho former case by changing the number o"f balls in the two bags without modifying tho proportion of black and white balls. Thus, taking 24, tho least common multiple of 8 'and 12, wo see that the fijst bag may bo replaced by ono containing 24 balls, of which 9 are white ; whilo tho second bag can bo replaced by one containing 24 balls, of whiol> 14 are white. The clianfe of drawing a white ball from one or other bag is in no way modified by these changes, and consequently the inferences to be deduced when a white ball has been drawn aro not modified. But the numbers being now e(|ual, we learn from what was shown in the former case, that if a white ball is drawn tho probability is - bag. 23 that it taken from the first |4 Now, by striking out common factors, it (iii.) . J3 J3 J3 J3 4' I write out I'.l', Ac, in full, to show tho connection between tho I.ririflion and onr formulas.) Now, tho second probability wo luirc relates to the drawing of a definite number of each kind, i.tcifying what kind is to be drawn once, twice, Ac. If the chance were required that 1 red, 2 white, 4 black, and 5 groon balls would be drawn, the e.tpression for tho probability would be — |lg I'.l'.V.V ll \± \± W' 4:" And wo should get the same probability, whatever the specifications might be. Further, since there aro 14s_ that is 1.2.3.4 different specifications possible, tho third probability which relates to the drawing of 1, 2, 4, and 5 of different kinds, without specifying which kind is to appear once, twice, four times, and five times, is equal to |12 I'.l'.V ]2_ |£nL ■*■" readily seen that the expressions (i), (ii), and (iii) aro to each other as ^ — ^ — jg, ^ and — : or, as — to —„ to _ ; so that (iii) is the 14.4.5 4..'> 108 480 20 greatest, and (ii) tho least, as was to be shown. + The reader should most carefully nolo tho point of the roa- Honitig hero. If we put an equal number of balls into each bag, wo have not modified £he pi-obability that the ball actually drawn will belong to ono sot or to tho other equal set ; the chances were equal before the separation, and they remain cfiuiil after the sepa- ration. But if wo put into one bag a smaller number of balls than we put into tho other, wo have modified tho clianco that the ball actually drawn will belong to the larger or to tho smaller set; tho chances were not equal before tho separation, but they are equal after it. Jdne 2, 1882.] • KNOWL.EDGE ♦ 15 Now let us apply this method to a more f^eneral case. Suppose one bag contains p halls, of which q are white, and that another baf,' "ontains )/ balls, of which q' are white ; a white ball is drawn — what IS the chance that it came from the foi-mer bag ? Ucre w<- take ;j ji'. the common multiple of p and p, and replace the lir.st ba;,' by nne containin<^ pp' balls, of which p'q are white ; the second by a pp' balls of which pq' are white. The numbers are now equal, and, therefore, our former rule gives ^-i — , as the chance pq+p'q that the drawn white ball came from the first bag ; and — — ^ pq+pq as the chance that this ball came from the second bag. If we divide the numerator and denominator of these expressiops by pp' we obtain expressions for these chances which are readily interprctable into a law for all such cases. The former expression becomes the latter becomes and since - is the probabilitv of drawing a wliite hall from the I> first bag if this bag is selected, while 2- is the probability of draw- P' ing a white ball from the second bag if selected, we have this general law : — If the chance of drawing a white ball from first bag is Cj and the chance of drawing a wliite ball from the second is Cj, then if a white ball is drawn, the chance that it came from the first bag is 1 ;.- , the chance that it came from the second is C, C, + Co But the bags of balls are merely illustrative, and we obviously proceed at once to this general law : — If there are two hypotheses equally likely, and one of which miiat be true, and on the first hypothesis the chance of a certain event is t'l, while on the second hypothesis the chance of the event is Co, then, if the event happen, the probability that the first hypothesis ' and the probability that the second hyj)0- is the true C, + Co thesis is the true one is . C, + Co Tlie importance of this formula will be more readily understood when it is applied to illustrative cases, to bo considered in our next number. PROBLEMS. Problem 43. — A tapering beam is 30 ft. long. At a distance of 10ft. from the thick end it is in er|uilibrium. The fulcrum is shifted 2 ft. nearer the small end, and the beam is then in equi- librium when a weight of 601b. has been suspended to the thin end. Find the weight of the beam.— W. D. B. Problem 44. — There are two drums ; the diameter of the larger is, say, 3 ft. ; that of the smaller is, say, 2 ft.; the distance from centres is, say, 10 ft. ; required the exact length of belting neces- sary for them.— W. D. B. [40]. — The equation belongs to a well-known class. It may bo depressed by putting p for — , when it becomes dt dr, dO dp """'di-dT-T/ d_p_\d(£) "dU~-J, do ' substituting and multiplying by 2 wo get d{p') —i^g- -t-2o/p'= — 2(/0, a linear equation of the first order and first degree. whence ji' - — Therefore l = '!L. ^^"-L) terms.—J. U. C. nnot be integrated in a finite scries of #ur ©abisft Column. Bv " Five of Clubs." A GAME FOR STUDY. I HE following hands are given by Clay to illustrate : rather, a class of cases — where it is necessary to disregard Spades- Q, Kn, 10, 1 3,2. Spades— 8, 7. Hearts— 9, 7, G. B Hearts— 5, 3. Clubs— A, K, Kn, 10. Clubs— Q, 0, S. 3. T) • 1 ■ Diamonds— 10, 7, C, 5. Diamonds-9. Y z B. Spades— A, K, C. Tnmp Car,!, Z. Spades— 9, 5. Fiv, ./St,„J„. Hearts— K, Kn, 2, 4. A Hearts— A, Q, 10, 8. Clubs— 5, 2. Diamonds— K, Kn, 3, 2. Clnbs— 7, G, 4. Diamonds— A, Q, S, 4. Score :— A, B, = 4. y, Z,=4. SiNGiLAR Hand a.nd Singclar Ill-Foetcne ; Yarboroighs. — The following is said to be a remarkable hand of cards dealt to tho Duke of Cumberland, as he was playing at Whist at the rooms at Bath, by which he lost a wager of £20,000, not winning one trick. The Duke's hand consisted of King, Knave, nine and seven of trumps (clubs); Ace and King of diamonds; Ace, King, Queen, and Knave of hearts ; and Ace, King, and Qneen of spades. The Duke leads a small trump. Right hand of the Dnke five small trumps, all the other cards hearts and spades. L>ft hand of the Duke Ace, Queen, ten and eight of trumps ; Queen, Knave, ten, nine, eight, seven, six, five, and four of diamonds. This hand, after winning tho first trick, leads a diamond. The Duke's partner's hand all insignificant cards." The above is extracted from the Kaleidoscope of Feb. 4. 1S23. It may interest the readers of your " Whist Column." Was the Duke's lead judicious ? In January last my partner had a Yarborough hand dealt, and many years ago I was at a party where one was dealt. I imagine few people came across two such. — R. G. [In " Coolebs on Whist," there is a somewhat similar case, only instead of failing to make a trick, the holder of the strong hand loses five by tricks. Coclebs says, a lead of trumps from such a hand is wrong. But ninety-nine players out of a hundred would lead trumps; and in my opinion the hundredth would lead wrongly. Wo must not judge by the event in such cases. Tlie whist-player can only jilay according to probabilities ; and tho chances arc in favour of the trump-lead turning out well. It is far more likely. f.'r instance, that, it a Heart is led (the Hearts suit being already established, bo it noticed), tho adversary will ruff it, and perhaps establish a cross ruff, than that tho cards would be so singularly dis- tributed in the other hands, as they wore in this case. I suppose, for example, that tho cards had lain thus: — The Duke's hand, as above (call it A'a hand) ; B's, small cards, no tnimps ; Ps hand, the four trumps named above, no spades, four hearts and diamonds ; Z'a hand, five remaining trnmps, no hearts, three spndea and diamonds. Then, if --I leads from his long suit, ho loses two by tricks, which, with such a hand, and a plain suit lead, is singular ill-fortune. Yarboroughs are more common than our correspondent supposes. Within the Inst eight months wo have come across three. Tho editor of tho Wcstmimtcr Payers mentions two as occuiring to him- self at the same sitting. — Five of Clubs. 0UV Cbcsfs Column. Puoni.FM X, . 2G, p. 401. Q to KtKii Q to QG or R to yK2 K to Kl3 (to) 16 • KNOWLEDGE [June 2, 188?. games by Leonard P. Recs, p. 597. Xo. 40. 1. Q takes R(ch) K takes Q ■2. Kt takes P(cli) K to Ktsq 3. Kt to B6(ch) K mores 4. li to KS(mate) Xo. 41. I 1. R toQ4(cJ0 K toRt I 2. K to UMch) K takes K I 3. Kt to B5(cb) and wins if 2. K to Kt3 I 3. IJ toKtl(oh) wins ■\Mnte to play and nmt Mackenzie ... Steinitz .. 10^ Noa Schwarz ... H ... 8^ Winawer .. 10 .. 91 .. 9 .. 8i Blackbumo... Mason Euglisch Hruby Zukertort .. Bird ... 7i ... 74 ... G VIEXXA INTERNATIONAL TOURNAMENT. Fleissig H Tschigorin (J Paulsen 5i Weiss 5i Meitner 5 Ware 3i Of special importance was the enconntor between IJlackburno and Zukertort, which took place on May 21. Blackburno won. "n the same day Mackenzie lost his first game (oat of eleven) to Schwarz, an experienced Itnngarian player. In the course of the week, Blackbnrne, however, lost two games — one against Paulsen, the other against Noa, also an Hungarian. .Steinitz showed great improvement, and out of the si.t games played in the week he won five and drew one (Mason). We are eorry to hear that Zukertort is indisposed, and owing to his bad state of health he is doing badly. Out of the six games i)Iayed he hag lost fonr and won two. Mason won two, lost one, and drew three (Blackbume, Steinitz, Fleissig). [By Tetejraw.1 Vienna, Tuesday night. Score of English team : — Mackenzie, Hi (beat Meitner) ; Steinitz, 11 (beat Schwarz) ; Blackburne, probably 10 (at the time of wiriiii,' :he score, his game with Englisch a.ssumed a drawn aspect); Mascm, 10 (beat Weiss) ; Zukertort, SI (beat Bird). REVIEW. A Complete Guide to the Game of Ch By IF. " Chess is such a noble game, How it does the soul inflame I "• " There are moments in our lives when we have nothing par- ticular to do " ; in these moments we might peruse the above book, which is a novelty of its kind. It contains a vast amount of useful information for a beginner, hitherto not contained in any other jKJok. The book may bo called a "Chess Dictionary," as it deals with every item connected with Chess. For instance, speaking about the board, the author says, " The best boards and men are those made of hard woos ni iiu- 017| The Stars f..r .. 619 Wcnlherrlui not. .... 6M li25-e2S fil9! CORRKSPON Urother^, I KkviKWS: !■ and Cnllu) Solar En,Tt:> NOTICES. Spschi, Noticb to our Hka7)bb.s.— Fourpsnoe each i linliers for copies of No«. 3 anl 3. Apply c (jueeu Stroot, London, W.C. Thft First Volumo of Ksowlkdob will be publiBhed tliiflweek, bound in red clolh, gilt lettered. Price 10». 6d. Vol. I. will comprise the nnmbors from tho commencement (Nov. 4, 1881) to No. 30 (May 20, 1882). As there is only a limited number of copies, the Publishers advise that orders should be sent ia without delay, to prevent disappointment. The Indei to Volume I. will also be published, price 2d,, post-free 2ld. nindint' Cases for Volume I., price Is. 6d. each. Complete copies bound (iiR-liKliiiK Title, Indcl, and Case) for 28. »>1. each. 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The terms of Annual Subscription to the weekly numbers of EjrowLBDOB ara a follows:— '• "■ To any address in the United Kingdom 10 10 To tho Continent, Australia, New Zeahuid, South Africa & Canada 13 0 To the United States of America <3.25. or 13 0 To the East Indies, China, &o. (itiif lirindisi) IS 2 All subscriptions are payable in advance. can Literary Bureau, Tribune Btiildings, OFFICE: 74 & 75, GREAT QUEEN STREET, LONDON, W.C. June 9, 1882. ♦ KNOV/LEDGE p^ MAG^^INE OF SqENCE ^ ^PlAINIlifORJED -EXACTL^DESCRIBED, LONDON: FRIDAY, JUNE 9, 1882. Contents of No. 32. The Grosrenor Gallery _ EDglish Seaside Heallh Besorts. Bj- Alfred Uariland. Classifica- Antiqnitj of Man in Western Europe. BvE.Clodd. Part III. Crrstals. Br'AVilliam Jago.F.C.S., A«30C. Inst. Chem. Xo. HI. (JlltutraUJ) Nighta with a Three-Inch Telescope. Br •■ A FfUow of the Roval Astro- nomical Society" {IHus'trateJ) ... Photographv for" Amateurs. Bt A. Brothers, "F.R.A.S. Part IX. ... Weather Charts Butterflies and Moths. By W. J. H.Clark 24 EasT Lessons in Blowpipe Chemistry. Bt Licut.-Colonel W. A. Ross, UteR.A. Lesson VI 23 The Babylonian Calendar 26 Siemens on Solar Energy 27 Correspondence '- 2S Answers to Correspondents 29 Our Mathematical Column 3''> Out Whist Column 31 Our Chess Column 31 THE GROSVENOR GALLERY. A FOREIGNER who should take a hasty glance through the Grosveuor Gallery might at first suppose it was intended as a place of refuge for works of art (Heaven save the mark !) which elsewhere would be regarded as insults to the public. Looking more carefully through the collec- tion, he would find many charming works manifestly placed here for their excellence, not for the grossness of their defects. It would probaVily remain a mystery to him how works so unlike in character came to be side by side in the same collection, did not some English friend tell him of the idiocies of the lesthetic school of art, and of the insolt^nt madness of that school of which Mr. Whistler is the most peccant — we wish we could say, the only— representative. In the early youth of painting (passing over the Egyptian, Greek, and ancient Roman schools, of whose works we know very little), artists had crude ideas of drawing and colour- ing, they knew very little of perspective and anatomy, and they had scarce any models worth copying. They had, as children have, a taste for bright colours ; and they pos- sessed what children, as a rule, do not possess, the power of depicting beautiful colours, though in inharmonious combinations. Thus we find in their paintings imperfect perspective, angular figures, impossible bones and muscles, unwholesome complexions, and gaudy ornamentation — but, occasionally, very beautiful tints. Of aercal perspective the early painters knew simply nothing — or, if they knew anything, they made not the slightest attempt to apply their knowledge. The paintings of the early schools are therefore neces- sarily defective, and so far as general effect is concerned, they are, for the most part, in the artistic as well as ordinary sense, simply hideous. But they are full of interest Moreover, scarcely one of the paintings by the ablest of the early painters fails to show here and there features which, considered iiioni', are of exquisite beauty. The charm of antiquity appeals to us as we study tliese ancient paintings. The practised eye can see in them also the germs of the noble works of the great painters who came afterwards. In every national collection these old paint- ings have a place of honour ; every student of art ex- amines them with loving care ; and if occasionally there is something of the feeling with which we look over a portfolio of pictures by a child, if there is sometimes a sense of amused wonder at the quaintness of the concep- tions and the inadequacy of their rendering, the feeling is softened, much as when, looking at pictures by a child who is dead, the thoucjht comes to us that his tiny fingers never learned to hold pencil or brush with firmness and vigour, that he was never more than the child-artist. And because men of sense and of artistic skill study with love and tenderness these quaint old beginnings of modern art, there " come you in " certain idiots, hoping to beguile us of our esteem by copying the defects of those beloved old masters who tlourished during the childhood of painting. As if some inane noodle of middle age should take the grotesque drawings of a child, and copy all their absur- dities, these imbeciles of the present day (when art, though it should at least have reached its full manhood, ought not to be in second childhood) carefully picture sickly, ill-shaped beings, in impossible attitudes (they call them mediwval, but people in the middle ages were not all crippled and de- formed), adorned with tawdry, ill-arranged frippery, and wanting even what the quaint old pictures possessed, occa- sional touches of beautiful colouring, and occasional bits of effective drawing. Take, for instance, " The Feast of Peleus," by E. Bume Jones, Xo. 1.^7 (East Gallery). For what earthly reason is a long-su tiering public to be insulted by a picture in which the Laughter-Loving Goddess of Beauty is represented as a high-shouldered, hideous sksieton 1 and in which tho two rival goddesses who claim the apple (marked by Discord " for the fairest !") are as ugly and dyspeptic as their dreary rivaU — uglier they could hardly be. There was some excuse for a Ghirlandajo or a Botticelli who represented a saint as one who had lived an ascetic life — in other words, as a pale, half-starved weakling. But there is not common sense or even decency in picturing these wan and wasted wretches as " the three great goddesses who claimed the golden apple as the prize of beauty." In the "Tree of Forgiveness,"' by the same (No. 144) we are pained perhaps more by the oftensiveness of the sub- ject (in an artistic sense) than by the hideous com- plexions and expressions (we say nothing about the utterly incorrect proportions of Demophoon's chest, belly, and limbs, seeing that the painters of this school must be all wrong anatomically, or they would not be media>val). A lady who had been an almond tree for a while might have such a colour (for aught we know), and a man upon whom such a creature suddenly sprang out might be excused for wearing a very uncomfortable expression. But Venus Aphrodite sick and sorry, worn, wan, and wasted, we really " cannot away with.' Of the three ladies in "The Mill" (No. 175), by the same painter, we can only say that they are suggestive rather of stale rhubarb than of faint lilies; and a similar remark applies to the Angel with complicated wings in No. 292, whose melancholy expres- sion by no means accords with the usual ideas respecting angelic happiness. It is, indeed, easy to fall into a way of lightly ridiculing this absurd school. But their offences merit more serious chastisement than mere ridicule. The mischief such paint- ings do is very serious. Among the inexperienceil they create utterly false tastes. They are not only bad in them- selves: they are bad in their indirect influence. They kill men's love for tho works of the old paintert. If there are any who have done more than otliers to dt^stroy our appreciation of those works, to make tiiem positively hate- ful and disgusting to us, instead of intei-esting and delight- ful (as rightly viewed they should be), it is their so called followers, who admire them for their defects, carefully 18 KNOWLEDGE • [June 9, 1882. copy their defects, and liave notliing in common with them but the worst of their defects. But if we feel contempt for the paltry aflectation of the old style, with what feelings must we regard the mad new style, the Noctin-nes in Blue and Silver, the Harmonies in Flesh-colour and Pink, the Notes in Blue and Opal ! We are shown a sooty-faced, ill-shaped creature, with linil)S entirely out of proportion (do look at that left arm !), on a dirtv-black background, with smears of vermilion on necklace, lips, and hat, and we are told it is — not a Horror in Soot and Ochre, as our eyes tell us — but (forsooth) a Harmony in Black and Red ! A dark bluish surface, with white dots on it, and the faintest adumbra- tions of shape under the darkness, is gravely called a Noc- turne in Black and Gold. A few smears of colour, such as a painter might make in cleaning his paint-brushes, and which neither near at hand nor far oil', neither from one side, nor from tlie other, nor from in front, do more than vaguely suggest a shore and l>ay, is described as a " Note in Blue and Browni," and purports to present that well-known and lovely spot, St. Brelade's Bay. Criticism is power- less here, because one wlio found these pictures other than insults to his artistic sense, could never be reached by reasoning. We are not sure but that it would be something like an insult to our readers to say more about these " things." They must surely be meant in jest ; but whether the public have chiefly to tliank Mr. Wliistler, or the managers of the Grosvenor Gallery, for playing oft' on them this sorrj- joke, we do not know, nor greatly care. Meliora canamus .' {To he continued.) ENGLISH SEASIDE HEALTH-RESORTS. By Alfred H.wilaxd. CLASSIFICATION. BEFORE describing the seaside towns usually resorted to for liealth or change, either singly or in groups, it is necessary that they should be classified in such a manner as to assist the reader in forming a correct idea of their general and social climatic difi'erences ; for, when this part of the subject is clearly understood, health-seekers and their advisers will be less likely to err in the too-frequent direction of expecting from certain health-resorts what Nature has never given them to bestow, and will be more likely to find what they want, when, after first a-scertaining what their bodily conditions absolutely require, and what, from their hereditary tendencies or other peculiai-ities of con-stitution, must be carefully avoided, they study each group and each member of it, with all the knowledge they I>os,sess of its characteristic climatic properties, and, after doing so, select such a resort as will fulfil their health- requirements,' without evoking latent tendencies to disease — a most important point to be considered, although one unfortunately too frequently neglected. Health-resorta must be studied — I. As to latitudinal and longitudinal position ; for the English coast, including that of Wales, is between C° 1' 4.'»" degrees of the former, and 7^ 1 r .0.5" of the latter, and thus stretches over an area including a remarkaVjle variety of climatic factors. As re- gards latitude, the most southerly point is the Lizard Head, in the district of Helston, Cornwall, 49^ .'JG' .'J.5" lat. N. ; the most northerly, Berwick-upon-Tweed, in Northumber- land, 5.0'' 38' 20" lat N. As to longitude, the most easterly point is Lowestoft, in the district of Mutford, Suffolk, 1'' 31' 25" long. R ; and the most westerly, the Land's End, in the district of Penzance, Cornwall, 5' 40' 30" long. W. II. As to their position on the seaboard ; whether they enjoy the warm moist air from the Gulf Stream, the bracing air of the North Sea, or an atmosphere brought by the winds after it has lost its sea character by passing over thousands of square miles of continent. III. As to their site on the coast ; whether they are elevated on precipitous clift's, having a protective influence, or on low-lying, flat shores, over which the winds find no resistance ; or in deep \alleys facing the sea, where the- natural force of the wind is increased, like that of the tidal wave, inl^funnel-shapcd estuaries ; as to the heights behind them, whether, although they may be protected by them from some winds, these heights do not act injuriously, on the whole, by preventing due air flushings when the winds from the sea are only moderate in force, especially in the case of large towns where there is much smoke. IV. As to the depth or shallowness of the sea ; whether the beach ofters opportunities for exercise and recreation, or whether at low tide there is a wide expanse of mud exposed. V. As to their exposure to or protection from certain prevailing winds, and whether their street arrangement is such as to afford the health-seeker opportunities of availing himself of natural advantages. VI. As to the prevalence or scarcity of certain diseases in the resorts themselves and in the neighbouring districts, and as to the zymotic death-rate. VII. As to the geology and physical geography of the site and its neighbourhood. VIII. And, as far as practicable, as to the temperature, its monthly mean, daily range, its mean monthly maximum, j minimum, and range, the rainfall, and, wherever it can be ascertained, the temperature of the sea. The above is an outline ;of what we hope to present to- our readers, and we need hardly say that we shall be grateful to all who will kindly assist us with reliable in- formation on the above or any other points of interest connected with the seaside health-resorts of England. We will now give a list, under our first heading, of some of the resorts which will more or less command our attention in future papers. I. Latitudinal Position. On the East Coast. — Between .Ol" and .02° N., Deal, Ramsgate, Margate, Heme Bay, and Southend. Between trl° and .03° N., Lowestoft, Great Yarmouth, Cromer and Huntstanton. Between .03° and 54°, Great Grimsby. P>ctween 54° and 55° N., Bridlington, Filey, Scarborough, Whitby, Redcar. On the West Coast. — Between 50° and 51° N., Sennan (Land's End), St. Ives. Between 51° and 52° N., Ilfra- combe, Burnham, Weston-super-Mare, Clevedon, and Tenliy. Between 52° and 5.3° N., Aberystwith and Bournemouth. Between 53° and 54° N., Beaumaris, Bangor, Penmaenmawr, Llandudno, Rhyl, New Brighton, Southport, and Black- pool ; and between 54° and 55° N., Morecombe Bay. On the South Coast. — Between 51° and 52° N., Dover, Folkestone, and Ilythe ; and between 50° and 51° N., Hastings, and St. Leonard.s, Ea.stbourne, Seaford, Brighton, Worthing, I Littlchampton, Bognor, Isle of Wight, I'.ournemouth, I Weymouth, Lyme Regis, Exmoutli, Dawlish, Teignmouth, \ Torquay, Dartmouth, Penzance, and the Lizard. The reader will kindly correct the followiiif; errata in the first paper, p. 3, col. II. For " Hcasonably," read " seasonally " ; after " distribntcd " insert "in"; for " toach," read "teaches"; and I " before such places " omit " that." I The " Christian Commonwealth " has been permanently enlarged from 16 to 24 pp. Jdxk 9, 1882.] • KNOWLEDGE • 19 ANTIQUITY OF MAN IN WESTERN EUROPE. By Edwakd Clodd. SCANTY as are the bones of Palieolithic man, no unprejudiced person can deny that the tools and weapons of the Drift are products of human skill, low in the scale as tliis may be ; for they have defined, purposeful shapes, whicli were artificially produced, because they can be thus formed only by the application of blows or of pressure in a peculiar way, as modern experiments show. Moreover, they indicate selection on the part of their fashioners, since they cannot be made from every kind of tlint. They are found, in striking correspondence of form, wherever man is kno^\Ti to have wandered, or may be presumed to have wandered, over the earth* — in the allu^aals of the East, the laterite or brick earth of Madras ; in the river-gravels of sacred and classic lands, by the Sea of Galilee, and along the valley of the Tiber ; in brief, in every explored part of the Old and New Worlds " from Cliina to Peru. ' They witness to the wide distribution of rude tribes of hunters in the lowest stage of culture, of whose aboriginal home we can only speculate, of whose ultimate fate nothing whatever is known. Into this Universe, and v;hii, not knowing, Nor irhcnce, like water willy-nilly flowing; And out of it, as wind along the waste, I know not whither, willy-nilly blowing.f The description of rude Northern tribes given by Tacitus may not unfitly — rather with added force — be applied to them. "They are wonderfully savage and miserably poor. They have no weapons, no horses, no homes ; they feed on herbs, and are clad with the skins of beasts; the ground is their bed, and their only hope of life is in their arrows, which, for lack of iron, they sharpen with tips of bone. The women live by hunting, just like the men, for they accompany the men in their wanderings and seek their share of the prey. And they have no other refuge for their young children against wild beasts or storms than to cover them up in a nest made of interlacing boughs. Such are the homes to which the young men return, in whicli the old men take their rest."! The implements of the ancient Stone Age are certainly not more recent than the water-laid beds in which they are found hitherto undisturbed, and the height of these, ranging from .'iOft. to as much as 200 ft., in some places, above the present river-levels, is proof of enormous anti- quity. An appro.ximate estimate of the time required for tiie deepening of a valley is furnished by the quantity of sediment carried yearly by the river flowing through it to the sea. The data at hand for this result are slender, but Professor A. Geikie shows that the removal of one foot of rock occupies in some cases a few centuries : in others as many chiliads. For example, the Po appears to lower the surface of the area drained by it at the rate of one foot in 729 years, while the Mississippi takes G,000 years to effect a like result. And although the larger volume and flood of the Pleistocene rivers — betokened by the coarse gravel, the large unrolled stones, and the mingled remains of different species of animals which alternately occupied the land, as the climate of Pleistocene times was now genial, now arctic— scooped out the valleys at a quicker rate than the rivers of to-day, the removal by the Somme, • Scandinavia must be excepted, the finds there being exclusively Neolithic. + Kubiiiyit of Omar Khayyilm, xxix. J Gcrmania, c. -W. for example, of masses of chalk and overlying Tertiary (letiris (of which its valley entirely consists) to the depth of 150 ft, through a channel many miles in length, demands an Immense period. Subsequent to this, what vast lapse of time is required to explain the gap between the Drift and the early pre-historic period when the polished stone-using peoples arrived, so that, as Dr. Evans remarks : " we must, for the present at least, judge of the antiquity of these deposits rather from the general effect produced upon our minds by the vastness of the changes which have taken place, both in the external configuration of the country and its extent seaward, since the time of their formation, than by any actual admeasurement of years or of centuries.* But these implements of the river gravels do not tell the whole story about Palieolithic man. Speaking broadly, he falls into two divisions — Drift-man and Cave-man ; the tools and weapons found in the limestone caverns of Western Europe marking a distinct advance, perchance due to another race, over those of the earlier period. For while, as has been remarked, the gravel-beds yield only oval-shaped flints and leaf-shaped flakes, the caves furnish flint saws, lance heads, awls, barbed weapons, bone needles (in one place a stone drill lying near them), imbedded with charcoal and the debris of animals eaten, as the musk sheep, bison, and others, especially the reindeer. From the enormous numbers of this creature, which appears to have formed the chief food of the rude hunters, the cave deposits are often spoken of as belonging to the Reindeer period, in contradistinction to the Drift or Mammoth period. The precedence of decoration over dress notice- able among savages, perhaps finds illustration in rude strings of animals' teeth and shells ; while a soft red ochre (o.xide of iron), which occurs among the relics, shows that the Reindeer men painted their skins. But we are anticipating. From the earliest times, " the clefts of the valleys, the caves of the earth, and in rocks," have formed the natural shelters of barbaric races. And, although the traces of bone and other relic-yielding caverns of tertiary and early quaternary times appear to have been swept away in the momentous changes of land surface, the caverns of subse- quent periods are rich in remains wliich enable us to con- struct a more vivid outline of man in the ancient Stone Age than do the scanty and rude relics of tlie Drift, Implements of the Drift type occur among tlie oldest layers in caverns, but the upper deposits supply the evidence of advance to which reference has been made. Following M. de Mortillet's' divisioi\s for a moment, the Thenaisian and Acheulian epochs embrace the Drift period ; the Moustcrian, Solutrian, and Magdalenian epochs the Cave period. Not that these latter divisions are to be taken as hard and fast, but as overlapping, because they may, in fact, represent no great difference or extended succession of time. And for the present purpose it is better that in place of explanation of. or comment upon, the method of selecting specific implements as types of each period adopted by M. de Mortillet^ an account lie given of the deposits and contents of one of our most celebrated English caverns, premising that these will aftord a fair idea of the bone-caves and rock-shelters of tlie con- tinent, except where the latter have furnished certain remarkable specimens of primitive art to be presently re- ferred to. Before entering our cave, which shall be Kent's Hole, near Tnr(|uay, let us briefly explain how the deposits in it, and in like caverns found in limestone rock, have been ' " Ancient Stone Iniplemonts," p. 621. 20 KNOWLEDGE [Juke 9, formed, because the almost imperceptible rate at which, in some cases, they have l>een laid down has an important liearing on the age of the contents imbedded within them. The surface-wat<»r tinds its way through some crevice or tissure in the rock, and being moi-e or less charged with carlwnic acid deri\ed from the atmosphere, and from decayed vegetable and other matter in the soil, becomes a very powerful solvent, under which the rock, converted into carlionate of lime, is carried away in solution. But while much thus runs off, Nature, true to her cyclical action, begins to refill the cavity which she has eaten away. Drops of water, holding the lime in solution, ooze from the roof, and, falling on the floor, gradually form beds and l)Osses of stjilagmito, wliich hermetically seal whatever de'iris may happen to be lying about, while such portions of the dissolved limestone as remain clinging to the roof after evaporation of the water from them hang icicle-like therefrom, and gradually form the beautiful columns of stalactite which adorn many of the famous caverns of the world. CRYSTALS. Bv William Jago, F.C.S., Assoc. Inst. Cixem. No. III. IN our last paper we studied crystals, artificially pro- pared, under the microscope ; it is our purpose in this numljer, still using the microscope as our means of investi- gation, to examine crystals which have been formed natu- rally. From what has already been stated, it will be seen how universal is the tendency which matter has, when assuming the solid state, to also become crystalline. Rocks form no exception to this rule, and in many speci- mens of the granitic type, large and well- formed crystals are found embedded in the finer portions of the rock. The name "porphyry" is now restricted by geologists to rocks of this class. The stone of the large polished granite fountain in St. Paul's Churchyard contains some very fine crj-stals of the minerals felspar and hornblende ; but not only is granite distinctly made up of crystals, but even the finer grained rocks, which to the naked eye appear per- fectly uniform in texture, are also found on minute exami- nation to be more or less crystalline in structure. Of recent years the application of the microscope in geology has l)een much extended, and now the description of any rock would not be considered complet<; without mention of its microscopic characteristics. To examine rocks with the microscope, by means of transmitted light, in the way most usually adoptf;d, it is neces.sary to prepare and mount extremely thin sections, these sections being often much thinner than paper. At pre.sent we shall not be able to give directions for the preparation of such specimens, but, with the Editor's permi.ssion, may make practical direc- tions for section-grinding and mounting the subject of a .separate paper on some future occasion. In the first paper of this series it was stated that the black, pitch like form of lava is instanced by the geologist as the type of glas.sy or non-crystalline rocks. Fig. 1 is a sketch made of such a piece of gla.ssy lava, "obsidian" from the Lipari Isles, magnififid to about 2.^0 diameters. It i.s almost a pure natural glass; the small black specks are probably embryonic crystals of magnetite (one of the natural oxides of iron). Such a rock is produced by the rapid cooling and golidilication of molt to 30 diameters.) Although the main portion of the rock is glassy, there are yet a few small crystals to be noticed ; the most interesting point, however, about the specimen is that it contains a number of small spherules, one of which occu- pies the centre of the field. It may be noticed that it has a radiated structure. Precisely the same formation is often seen in glass which has been maintained at a tempera- ture near its melting-point for a considerable time. The writer has several interesting examples of such glass in his possession. But, to proceed to some further proof of the crystalline nature of these spherules. Students of physics are aware that a ray of light undergoes a peculiar change on passing through a block of Iceland spar ; among other modifications, it is so altered that it is incap- able of passing through a second block of the same material if placed in a certain position with regard to the first. The light under these circumstances is said to he polarised. Micro- scopes for the study of rock sections are fitted with a pair of specially-prepared pieces of Iceland spar, called " Nicol's Prisms." One of these is fixed under the stage ; the other is either fitted over the eyepiece, or into the body of the instrument. These being placed in position, on rotating one of them, a point is reached at wliich, on looking through the instrument, it is seen that no light is transmitted. ]Most crystalline substances, on being placed between the prisms, possess the property of so modifying the beam of light as to effect its passage through the second or upper prism, and thus to the eye, neglecting for the time being those crystals inactive in this respect. This aflTords us a most ready means of discriminating between crystals and glass. The glass of the microscopic slide has no action on the light, neither has a purely glas.sy piece of rock ; but let th(!re be crystals present, and they are immediately seen, ilhiMiiiKated on a black ground. Viewed in this way by polarised light, the darker spherules of the obsidian Ijecome Ijright, wliile the rest of the rock appears black.' Leaving the glassy rocks, we may now glance at some specimens in wliich crystallisation has still further asserted itself. Th(! rock called Felsite is one which, instead of being glassy, is micro-crystalline in structure : the crystals are very small, but their optical behaviour leaves no doubt as to their natur(^ There are many rocks which contain, imbedded in a base of this kind, larger, but. still microscopic, crystals. Figs. .3 and 4 are examples of such. The crystals, though so' small, are often wonderfully perfect. Fig. 3 is a sketch of a micro-porphyritic basalt, from Unkel, on the Rhine ; the largest crystal occupying the centre of the field is one of felspar, several smaller crystals of the same shape may be detected, the remainder of the work being micro-crystalline. The next figure gives a JONE 9, 1882.] KNOWLEDGE ♦ 21 section of a fine crystal of nepheline, in Phonolite basalt, from Solllifrg Eisel. The crystal in shape is a hexaj,'onal prism, and has been cut almost at right angles to its base. During its growth it has enclosed within it other small crystals and part of the base of the rock. Round the outer edges this may particularly be noticed : it would seem as though the power wh'.ch determines the crystalline form, at the last, had just sufficient energy to complete the shape of the crystal ; but, with the growing rigidity of the cooling mass, lacked the strength to e.xpel these foreign particles, and was perforce content to enclose them within itself. By NIGHTS WITH A THREE-INCH TELESCOPE. "A Fellow of the Royal Astronomical Society. TO the east of Bootes lie the constellations Corona Borealis and Serpens, which we shall now proceed to examine. Beginning with the former (which really does present more than the ordinary resemblance to the object wjiose name it bears), we shall find a very interesting double star in ^ (map, Vol. I., p. 626), the components exhibiting well-contrasted colours. Its aspect, as seen with a power of 160, is shown in Fig. 33. a Coronas is a very pretty pair indeed ; it is delineated in Fig. 34, as viewed with the same power as the last star, a will be found in the sky as nearly as may be 10° N.E. of « Corona?. This is sometimes ranked as a triple star, as the pair shown in our sketch are fol- lowed, at a distance of .'il" or .'jS", by a minute blue star. a itself is one of what are known as binary stars — i.e., physically connected pairs; and, in the description of their orbits, about their common centre of gravity, its com- ticrpuiitia. ponents have separated from 1".3 in 1830, to something like 3".r) now. One of the most interesting of these binary systems, that of >; Corona', is uTifortunately (juite liopelessly Vx^yond the power of our instrument, as the two stars are now less than 0.5" apart, and are closing. Their distance varies from about 1.4" to 0.3", and their orV)it is described in something over forty years. There arc several pairs of telescopic stars in this constellation, all of them tolerably easy to divide, but it is very difficult to give directions for finding them in the absence of an equatorially-mounted telescope with divided circles. An easy one (Struve, 1,964) will be found a little to the south-west of I described above. While going over Corona, the student should not omit to glance at that most astonishing object, T Coronse ; the star which blazed up suddenly as a second magnitude one in the year 1866. Examined by our greatest English spectro- .scopist, Dr. Ifuggins, on May 16 in that year, it was found to exhibit a double .spectrum ; one analogous to that shown by our own sun, the other one that of glowing gaseous hydrogen ; this (possibly) indicating a conflagration on a stupendous scale. Subsequently to this the star faded to the 9th magnitude, revived again somewhat, and has since been irregularly variable. At present it appears as a star of about the OUh magnitude. It is situated on an imagi- nary line drawn from t Corona; to tt Serpentis, at rather less than one-third of the distance between the two from t. Serpens, to which we shall next devote our attention (Map, Vol. I., p. 626), is one of those straggling and sprawl- ing constellations so difficult to follow in the sky. Never- theless it is one containing many beautiful and interesting objects. To Ijegin with, a is a very wide and unequal pair, the smaller component requiring a good deal of looking for with a small telescope. We insert it here for the prettj contrast in colours which it presents. I Serpentis, shown in Fig. 3.5, is a very neat and pretty binary star. The components are at present separating, /i is, like o, a widish and very unequal pair, the small star, as in the former case, being bluish. S Serpentis is comparatively wide and easy. It will well repay examination from the richness of the region in which it lies. >- Serpentis, 4° north-east of ?;, is also wide and easy. As befcre, we men- tion it for the pleasingly- contrasted colours of its com- ponents. 5 Serpentis (9° south-west of a) is much closer, and very unequal. It will repay examination. 10J° to the north-east of « Serpentis, on a line drawn from that st.ir to Vega, will be found 49 Serpentis- a line pairr .^hown in Fig. 36. This is a binary s^ysteni, with a sup- ].os.d period of 900 years! .'i9 (or (/) Serpentis is a beautiful oV>ject, the colours of its close and unequal com- jicments being strongly contrasted. It is represented iu. Kig. 37. Smyth's directions for finding this star anv p(rhap.s as good as any. " To identify ."i".* Serpei.tis," h»- suvs, "let an east-south-ea.st ray be shot fn.m /> Herculis through .1, which will l)C found two-fifths of tlie way " (i".<., from /> Herculis to 59 Serjientis). Libra (Map, Vol. I., p. 626) is neither a striking oonst*-!!*- tion to tho naked eye, nor does it contain many objects acces- sible to the class of instrument we are employing. A small, but easy, pair of stars will bo found in No. 62 of Piaizi, XlVth hour. It lies 1.5" east by north of Spica Vircinis, or 2 A° south-west of i in the same constollation. 9 due west" of /3 Scorpii will bo found P. XV. 91, a not very ♦ KNOWLEDGE ♦ [June 9, 1882. close, but considerably unequal pair. < Libra' is a very ■wide and unequal pair, but worth looking at for its pi-ettily contrasted colours. Just to tlie north-west of 5 Serpentis, of whicli we have previously spoken, will l>e found that fine, compressed cluster of very small stars, No. 5 of Messier's Catalogue. It is scarcely resolvable in a 3-in. achromatic, and merely appeai-s like a nebula, brightening conspicuously towards the centre. We now arrive at that somewhat unintelligible constel- lation, Hercules, who appears on the maps and globes head downwards between the constellations of the Northern Crown and the Lyre, As our present object, however, is less to endeavour to reconcile the configuration of the stars composing this constellation with the counterfeit present- ment of an invert^'d hero, than to select from them curious and l>eautiful objects, suitable to the instrument we are employing, the map we use will supply all the aid necessary for tliis purpose. We say all the aid ; but, in truth, the map which should give the position of a quarter of the interesting objects with which this constellation teems, would have to be a very elaborate and crowded one indeed, ^^'e must then, perforce, confine ourselves to a few of the most easily identifiable. Beginning upon the confines of Corona Borealis, about 1 \° a little to the east of south of y Corona?, we shall find 23 Herculis. This is a wide pair, but we insert it here for the marked colour of the smaller star, which will be seen below, and just to the right, of its primary. i Herculis, a remarkable binary star, is quite beyond the power of our telescope — in fact, appears single with the means at our disposal If, though, wo fish along a line connecting »; and ; Herculis about one-third of the way »), we shall light upon an object which will amply repay us for any disappointment we may experience in connection with this. The object to which we refer is No. 13 of ilessier's Catalogue, and consists of a most glorious globular cluster of stars. How far we shall succeed in detecting its stellar character will depend upon the excellence of our instrument and the acuteness and training of our \'ision. We liave tried to indicate its character in Fig. 38. One- and-a-half degrees N. ))y E. of j) Herculis will be found another cluster (Messier 92), which the average eye and instrument will only show as a bright nebula. We may further note here that there are two planetary ncbuhe in this constellation ; but that only one of these is at all within the reach of a three-inch telescope ; and neither can l>e found with certainty, save in an equatorially-mounted telescope. PHOTOGRAPHY FOR AMATEURS. By a. BKOxnERS, F.R.A.S. IF kept standing in the dark slide for any length of time, the sf;nsitive collodion film will dry, and the time it will remain in a condition fit for use will depend on the tempfjrature of the air. Another disasito the polar regions are at any moment in excess or in defect of those which would result in equilibrium, there can never bo other than oscillatory movements in the interplanetary atmosphere. There will always be resistance to inflow— that is, to tho ^constant inflow, which the theory requires : there mil equally be resistance to [constant] outflow. RicHABD A. Pboctor. WiNNMSG Wagers. — It will hardly be believed, but our paper thus named has actually been understood by some of our readers as a guide to successful wagering ! It is as painful to havo to in- terpret sarcasm as to have to explain a joke ; but for the benefit of those (very few we trust) who havo misunderstood us, wo explain that the whole aim and purport of our paper was to indicate tho rascality of tho only kind of wagering which is ever systematically successful, — tho system pursued by the bookmaking fraternity. Wo might as reasonably bo supposed to inculcate the true principles of pocket-picking, if wo warned readers against the tricks of street thieves, as to advocate the tnio principles of ^vagering, when wo show how bookmakers swindle verdant bettors. Killing ENToMoLor,ic.\L SrKCiJiKN.s.— In tho column on "Butter- flies and Moths," p. 606 of Knowledgk, several methods of killing the animals arc described. Some twenty years ago, I tried many experiments with this intent, and finally discovered that the bisul- phide of carbon is effectual. It is a vorj" volatile liquid, its vapour very dense. The insects, either before or after pinning out, may be placed in a wide-necked bottle or a tin box in which is a piece of wool that has been slightly wettoil with tho bisulphide. U should remain thero a few minutes, as a shorter time only produce's temporary insensibility. I described this method in the ninth volume of A'aturc, and it has since been extensively used in Franco for tho destruction of phylloxera. — W. Mattiki: Wii.liam.i. Poim'a KxTiiCT li * rartmin cor* for Kheumalnm ud Ooat. Pond'i BztrMt ii » c«rt»iii cure for llmnorrhoidi. PoDd'l Rilnct in ■ c< Xumtered. For ronoenirnot of fondnlt, rin r^rrrin} to any leHtr, triU oblige b) mentioning i Ordert ekould be node payable ndti, AULettm EXOKXICGI. the daf qf publieat%on. tfkt^A it appeare. Qaeriee to the Editor rkirk require attention in the current ieeve ^ IJreaek the Pnblieking Office net later than the Saturday preceding ne mint be concise; thpT mnst be dr»wB 1 the form tdopted fcr lettera here, «o thot tber may Ro untouched to the Tmter* ; private comraunicationB, therefore, ae we'll as' queries, or repbes to DPrie* (intended to appear aa such) should be written on separate leaves. (U.) tettera which (either because too ioni;, or unsuitable, or dealing with utiera which others hate discussed, or for any other reason) cannot find place " In knowledge, that man only is to be contemned and des (t*t« of truisition '>'or is there anything more than fiiity of opinion."— Jorarfjy, ** There is no harm in making a raistalie, but great harm in me > mas who makea no mutakes, and I will show von Dothing."— Z<«iii7. " God'a Orthodoxy ii Troth."— CJar/es Kingiley. adverse to making none. 0\\x CorrrsponiJrnre Columns. TOBACCO AND COXSUMPTIOX. [418]— In letter Xo. 411, pnge 030, Mr. W. B. Wickcn proposes the use of tobacco a-s a preventive and cure for consumption. The fact that the Tnrks are comparatively free from consumption is, I believe, beyond doubt ; and it may be, though I do not think 80, that their habit of inhaling the smoke into the lungs keeps away that dreadful disease. On the other hand, how is it that consump- tion is so prevalent in our own counti^j- ? Wo are a great nation of smokers, and if we do not make it a point of inhaling tho smoke into cor lungs, a fair percentage of it mast necessarilv find its way to the organs of breathing. Personally, I do not i.lnr'r .niv f^n'th in tobacco as a care for consumption, for Ibelir-.- l,:is more to do with it than anything else. As a ; i,/, possibly, be of service, by keeping the cells of ; ,,,1 thereby prevent the accumulation of morbid hni.i.n-. I ur,.i,r(i smoke has, undoubtedly, some soothing effect, and alluys irritatinn of the lungs; for I find that when my laboratory is filled with arid fames, that I have no inclination whatever to eongh, as lung as I use ray pipe. With regard to the tobacco used by tho Turks, I may say that I have never smoked a stronger kind than that used with the nar- gillah. When on a visit lately to Constantinople, I one day ordered, ont of cariosity, a cop of coffee and a nargillnh. The latter, how- ever, soon proved too much for me, thoQgh tho smoke was drawn through three yards of tubing and about sii inches of water. After passing through so much, the smoke was still so powerfully noiions, that one fiuff satisfietl mo fully, and I was glad to resign the pipe to a stander-by, who finished it in happiness. The tobacco used with the pipe is different from that used for cigarettes. In Spain, too, the smokers draw tho smoke into their lungs, and will frequently engage in a very spirited argument before emitting it again. They seem to have no difficulty whatever in swallowing the smoke— in fact, it is their usual custom ; bat their tobacco is not unlike chopped hay in mildness. In conclusion, I will repeat that Englishmen consume a great deal of tobacco, and yet consumption is very prevalent amongst us. 1 believe that it is to oar changeable and humid climate that tho cause must be assigned, and this applies not only to consumption, but to all the diseases that the chest and lungs are subject to. Perhaps some of our medical contributors will give us their ex- perience in this matter, which I am sure is of great interest to many. I would just say one thing, and that is, that rather than believe the Turk's freedom from tubercular diseases is duo to tho manner in which they use tobacco, I ehoiJd say it is because of their abstinence from intoxicating liijuors. W. 0. TKOSiiER, F.C.S. THE LATE MR. DUNMAN. [tlOJ^The recent death of Mr. T. Dnnman has already boon noticed in your columns. Ue may be said to have sacrificed his life to his self-denying zeal in the work of popular education, and to an intense interest in tho teaching of Science. Will yon allow me to mention that a fund is being raised to help his widow to place herself in a position to support herself and lior two children ? Several members of the Council of the Working Men's College are on the Committee, and I am authorised as treasurer to receive con- tributions.— R. B. Litchfield, 4, Brjanston-street, Portman- square, W. TRICYCLES. [420]— In reply to H. R. L., I fear I can add little to tho infor- mation I have tried to give in my two articles on recent tricycles, which have so lately appeared "in K.vowLKiXiK, but if tho writer will ask for details of any particular machine lie may find wanting in what 1 have written, \ shall be very glad to furnish tho infor- mation to the best of my power. JonN Browning. MILDNESS OF THE SEA COAST. [421] — The cfloct of the near neighbonrh.iod of tho ocean in moderating cold seems to be well illustrated by comparing the minimum temperature for Valentia, given in your weather reports for three weeks, ending April 29, with those observed at this station — Killarney — distant inland from Valentia 50 miles. The minima here were loiter than at Valentia on those 21 days as follows : — (The amount is given in whole degrees) — 5, 8, 4, 2, 1, 0,6, 8,-1, 4, —1, 1,2,2,0, l,e, 8, G, 1, 1. The mean difference is 3°. This is a somewhat striking exempli- fication of the well-known effect of the moderating influence of tho presence of the sea. I may add that the instrument used here has a Kew verification. It would be, I think, an improvement to give the hour of tho barometer readings in your Weather Reports. G. R. Wy.n.ne. THE "COLD SNAP" IN MAY. [422]— Permit mo to suggest as a reason for the low tempera- ture of u week in May thet there is usually formed in that month a region of high barometric pressure in the north, causing prevalent easterly winds over England. JYequently this wind is light and anti- cyclonic, and, after a period of cloudy skies, there is a clear sky for several nights. This, with the comparative calmness of the atmo- sphere, promotes rapid radiation from the earth. The ground tempe- rature falls decidedly below freezing-point, and tho air is cooled rapidly in the stratum next the earth. I believe in this direction must be sought the cause of the cold snap. Later on in the season tho amount of heat received from the sun in its longer ])eriod above the horizon is sufficient to prevent the excessive loss by radiation experienced in May, even in the clearest calmest Hummor iiiglits. (i. R. WvNNE. POPULATION OF TllH EARTH. [423] — On a globe 2 ft. diameter, the Dead Sea appears as a small coloured dot, but if it were frozen over there would bo room on its surface for the whole living human race, allowing six stjuarc foot for each person, and were they suddenly to bo engulfed, it would merely raise the level of tho lake by some four inches. One hears at times very wild statoirionts as to tho depth tho earth would bo covered if all the ])eoplo who have lived were laid side by side on its surface, estimates running from four feet upwards; but if we suppose the earth to have been as populous as now for 0,000 years (200 generations), the whole number could have been decently buried in graves 5j It. x 2 ft. within tho British Isles, and some 7,000 square miles to spare. I have taken tho present jioiiulation, as ^,'lvtn by tho Germau statisticians, at 1,450 millions (nearly). W. W. M. STAR SPECTROSCOPE— GLASS STYLOGRAPHS— MAGNI- FYING POWER. [424] — With a good 4-in. Cooke, jirovided with a Maclean's star- spectroscope, but mounted on an ordinary altazimuth tripod, with- out slow motions, the fuintnoss of star-spectra, and especially the unsteadiness of tho motion, made it extremely hard to determine the best focus. The way I succeeded is simple, and may bo useful. Slide out tho prisms and replace the concave cylindrical lens, fit the instrument as usual in the place of the eyepiece, focus on tho PeJ© JoxF. 9, 1882.] • KNOWLEDGE 29 star, till an intensely narrow and brilliant line of li.^ht is seen, and mark the focus obtained. Then, if the prisma are reinserted, ver)- good definition is obtained in the brighter parts of the spectrum. I have thus been able to see a wonderful amount of detail in the spectrum of Arcturus, and the general character of the spectrum of a star of the fourth magnitude. Several scratches thus made in the dark ou different occasions do not differ in position s'sth of an inch ; of course the focus will differ considerably with diiEfereut people, but with the same observer it suflBcts perfectly to set the instrument by the mark on each occasion, and saves a great deal of fatigue and annoyance. I noticed a remark in Knowledge, Xo. 21, that glass tubes for ink \vriting are very hard to make, and break easily ; as I have habitually used glass-tube pens of my own make for every kind of writing, including this, during the last two years, I venture to differ. Perhaps it depends on the way they are made ; but most people who use mine think them superior to the ordinary stylographs (12s. 6d. each). Anyone can make them for himself if ho knows the wa}'. Apropos of the magnifying power of a deep eyepiece ; a micro- scope with a micrometer on the diaphragm in the eyepiece will measure the power of the deepest lens very accurately and quickly. I tried it on the posterior lens alone of a 300- power eyepiece, and it gave 411 diams. as the result ; the image of the object-glass was so sharp that it could be easily thus measured to ji^'u^jth of an inch. H. L. C. SCKEW-DKIVERS. [425] — May I suggest, through the medium of Knowledge, that the simplest and cheapest method of improving screw-drivers, would be to make the heads of all screws concave, and the ends of all screw-drivers convex. With a little care at first, the driver would never slip off the screw, and one could always see if the screw were going in straight. C. Cakis Wilson. [I have long been of opinion that instead of a single cut in the screw^-head, two cuts forming a cross would be better, the screw- driver being made to match. — Ed.] THE MOCXTAIN "HERCULES." [426] — E. C. R. (413) is surprised that no expedition has been sent to verify Captain Lawson's discovery of the mountain " Hercules " in New Guinea. The reason is the same as that which has stood in the way of a verification of Captain Gulliver's discoveries of Laputa, &c. Everj- traveller who has had any expe- rience in mountain climbing knows how to treat an account of an ascent which commenced at 4 a.m. at the base of the mountain, which completed the first 14,000 ft. by 9 a.m. ; then reached the 8now-line at a height of 15,000 ft., and the summit, 10,314 ft. above the snow-line, and temperature 22" below freezing, at 1 P.M. The book is altogether a hoax, and a very feeble one. It was snuffed out immediately it appeared. W. Hattieu W 9nsU)fi£! to Coirfgpontifntsf. *^*Alt communications for the Editor requiring early attention thould reach the Office on or before the Saturday prrcedtng the current i».ii» o/ Kxowlbdob, the ineretuing circulation o1!. There is an interesting discussion of tho origin of Italian, French, Spanish, Ac, in Hallam's " Middle Ages." It sooms likely cnmigh that Latin was a special form of a langnage spreail over Western 30 • KNOWLEDGE [June 9, 1882. Europe, long before the time when Latin literature began — just as the Knglish of our best authors is a special form of a language spread over Britain and parts of Europe, long before English literature began. Rome could never have forced her language on so many nations. — J. V. M. Thanks. There are passages in Dr. Draj>er's works which are warm, but 1 liave seen none unfair. The other writer yon name (with whom, however, I thoroughly sympa- thise), lias been at times a hard hitter. It is very gratifying to know that you find Knowleikie free, as I have wished it to be, from sly thrusts. — \V. Saixdeks. (1) For lectures on the moon nothing can be more suitable than photographic slides, say from Xasmyth's Moon, used either with the oxyhydrogen light or a good stereoscopic lantern. (2) Probably, a submerged thicket ; but careful survey would be required to determine the point. — \V. S. No; the word was correctly enough printed " barometer." Prof. Huxley did not, however, imply that the barometer is highest on hot days, but that on the hotter of two days of equal atmospheric pressure, and when therefore tbe barometer should be of the same height, the mercury stands a little higher in the barometer tube. This is correct, but not for the reason ho assigns. It is the diminution of the specific gravity of the mercury, not the change in the bore of the tube, which causes the diftercnco.^A Re.\dek and ax Advkktisek. Tlianks. I quite agree with you about having the articles as popular as possible. I scarcely see how they can bo made much more popular without becoming trivial. Of course, some, as in our mathematical column, are not meant to be popular, but are for the benefit of special classes of readers. But we always give a fair supply, and rather more, of jxjpular matter. — J. L. Wihtaker. Wo gladly insert your letter. — W. SnAW Hayleb. It was unquestionably a sun- spot. Vou do not mention the power you used. — M. C. C. It would not bo easy to explain a real objective change in the colour of sunlight from golden to pure yellow during a partial eclipse. The effect was, I should think, subjective; there was a real diminution of light, and an illusory loss of colour. — T. Morgan". Sorry your letter has remained so long unanswered ; but the truth is, we get about three times as much correspondence as we can deal with, consequently some of it is four weeks old. If you send a short letter expressing your views respecting pyrological matters, we will gkdly insert it. THE TELESCOPE. A. B. C. There are only two Nebulae, 10 M. Ophiuclii and 12 Messier Ophinchi, in the neighbourhood of which you speak. As, however, the former is very nearly on a, line joining ft Serpentis and I Ophinchi, and produced as far again, while you say definitely that the object you observed was above such a line, there can be but little doubt that it really was 12 M. that you saw. This will be referred to in due course when Ophiuchus comes to bo treated of in the "Nights." Doubtless the reason why "F.R.A.S." ignored a Cassiopciac as a double star was that its companion is more than 1' 30" from it, so that they are really two separate and distinct stars, and in no legitimate sense whatever a pair or a double one. — W. H. Harbis. The simple numerical formula for calculating the focus of a lens equivalent to the two in a Huyghenian eye-piece is this : — Divide twice the product of their foci by their sum. Let us apply this to your own eye-piece, of which you say that the field lens has a focal length of — ths of an inch, and the eye lens a focus of - ths of an inch ; then multiplying these together (according to the precept), and the product by 2, we get by 2, or — Next wo 54, , 12 the object glass, by r^, the focal length of the eye-piece, we obtain ftj- an the magnifying power of the latter with that object- glass. — J. Smith. The amplifying power of a Barlow lens depends upon its position in the cone of rays from the object,-glaBS. If wo call the distance of the lens from (i.e. within) the focus of the object-glass d ; then if its negative focal length be 2 d, it will exactly double the power of every eye-piece. In other words it would give an amplification of 160 with your 80 eye-piece and of 800 with the 400 one. In your case this result would obviously be attained if you bad a Barluw lens of 8 inches (negative) focus placed 4 in. within the focus of your object-glass, or, in other words, 56 in. from it. [About three pages of "Answers " have been unavoidably held over.] dPur iflati;cmatiral Column. THE LAWS OF PROBABILITY. IT seems better to give the most general law for inverse probabili- ties before proceeding to deal with illustrative examples. This we proceed to do : — By extending the reasoning employed in the last paper, the reader will have no difficulty in seeing that if there are three or more bags, each containing tho same number of balls, of which p in the first bag are white, q in the second, r in tho third, and so on ; then, if a bag is selected at random, and a ball drawn at random proves to bo white, tho chance that the first bag was selected i selected p + tl-t-r + &c. p + q- ■&.C. that the second was the chance that the third and ill he have p + q + r + &c. any difficulty in making the requisite modifications where the several bags contain different numbers of balls. Tho method to be followed is precisely tho same as I employed in tho simpler case of two bags, and tho result is similar, viz., that if tho chance of drawing a white ball from the first bag is Ci, that of drawing a white ball from the second bag C..., that of drawing a white ball from tho third bag C3, and so on ; then, if a white ball is drawn from a bag selected at random, tho chance that tho first bag was C, selected is ^ — r?, — p?; — tvt ; t'le chance that tho second bag wag Ci-l-Cj + Cs-H&c.' selected : This result, extended to the more general case of which the bags of balls are merely illustrative, becomes the following genera) If there are three or more hypotheses all equally likely, and mutually exclusive, so that only one can be true, and if on the first hypothesis the chance of an event is Cj, on the second the chanceof an event is Cn, on the third C3, and so on ; then, if the event occur, and we know, further, that it must have resulted from some one of tho conditions inferred by the hypotheses, the ohanco that the first lijpothesis is the true one is -/^ — —^ — V. ,, — ; the chance that the second is tho true one is ■ Ci + C.-t-Cs-h&c. c; and so on. Ci + Co + C3 + &c. ' One step further, and we have tho most general law of all. The above law supposes all tho hypotheses to be equally likely in the first instance— a state of things obviously corresponding to the equal chances that any one of the bags will bo .selected. To illus- trate the case where the hypotheses are not equally llkoly in tho first instance, wo must assume that the chances of drawing the several bags are not equal. Now, if we consider the case of two bags, we shall bo able to deduce tho general law wo require. Thus, suppose there are two bags, and that the chance of selecting ; mat or seieci one or other must bo selected, tho sum of these proba- bilities must bo equal to unity) ; and, as before, let tho chance of drawing a white ball from tho first bag (if selected), be C,, that of drawing a white ball from the second bag being C5. Then we may represent these two chances by supposing that there are two bags of tho first kind and three of the second kind, all equally likely to bo taken ; for it is obvious that the chances that the selected bag belongs to the f onner or latter kind arc, respectively, - and -. Now, by the general law already obtained— if a white ball is drawn, the chance that it came from a specified bag of the first kind is, _-_ -.P' , or . i^i- , and tho chance that it camo C,-hC,-1 Co + CV-l-Cj 2C,-h3Cj from one or other of those two bags is ^^ +30"- Similarly, the chance that it came from one or other of tho three bags of tho , , . , . 3Cj second kmd .s ^^_^^f,^ Noticing how this result has been obtained, and proceeding at once to the law which the bags of balls illustrate, we obtain finally this general law, including all the preceding laws (of indirect pro- babilities) : — If an event cannot happen unless some one of a set of hypo- theses, III, H;, H3, Ac, be true (these hypotheses being mutually exclusive), the antecedent probability of U, being r,, that of ^2,0,, Jvsz 9, 1882.] KNOWLEDGE 31 and so on ; and if on the hypothesis U, the chance of the event happening is C,, on the hypothesis U« the chance of the event liappening is Co, and so on|; then, if the event hapjen, the chance that H, is true is c,C, . c, C, + fo C» + C3 Cj + &c. ' the chance tliat Ho is true is Co C; ; c, Ci + CoCs + CjCa + Ac. and so on. (To le Continued.) SoLrTiox OF T's Problem. — Upon the line OB, taken = !>, con- struct the n-sided polygon, OBGD, &c. (in the figure n=G). Join the two alternate corners, O and G, by a diagonal OG. Upon OG as a base construct the triangle GAO, making the two sides OA and GA=a and e respectively, and taking care that A and B lie on opposite sides of OG. Join AB, and on it construct the polygon of n-sides ABCLKI, whicli is the polygon required. For By construction OA = a, and OB = b; also the triangles GAB and BOC are equal ; because GB = BO, AB = BC, and angle GBA = CBO (each being equal to the interior angle of the «-sided polygon diminished by the angle ABOl. Hence OC = AG = <:. Q. E. D. Scholium. — If the point P' be determined on the same side of OG with B, then the line BP' will be the side of a polygon fulfilling the conditions of the problem, except that the point O will lie outside of the polygon. iBuv 2231)151 Column. By " Five op Clubs." PLAY THIRD HAND. THE general principles which should guide the play third in hand are — First, and chiefly, to help and strengthen your partner as much as possible in his own suit ; secondly, to derive all possible advantage from any strengthening cartl he may play in your own suit ; and thirdly, to retain as long as possible such partial command as you may have in an oppo- nent's suit. You can generally toll (from the lead, the play second hand, and your own hand) whether your partner has led from strength, or to strengthen you, or from a weak snit in which ho has no means of knowing your position. This will bo obvious from what we have already said about interpretation of the lead and the play second hand. Your play will be guided accordingly. Let us begin, tlicn, by considering the play third in hand : and afterwards, as heretofore, with the lead and second hand, we can consider the inferences to bo tlrawn from the play of particular cards third in hand. If you hold Ace third in hand, and neither King nor Queen, yon play it in plain suits, unless King or Queen has been led. Tlio only exception to this is when ten has been led and you hold Ace, Knave, when it is best to pass the ten. With Ace, King, you put on King, as a rule. But with Ace, King, and more t'.ian one small one, a good hand and four trumps, you should not put King on your partner's Knave, but pass tlio Knave; fourth in hand is sure to take the trick ; but when ti'umps are out you are tolerably sure of getting in again, when you make two tricks at least, and [irobably three in the suit. On the other hand, with Ace, King, and small ones, but only three trumps, you should not pass the Knave. Tho principle here applied is general. With good strength in trnmps, you may usually finesse with advantage in a suit in which your partner has led a strengthening card ; but when short in trumps, such a finesse is unadvisable. With Ace, Queen, alone or with others, you should finesse tho Queen, or the lowest card in sequence with the Queen — unless a single trick will make or save the game, when, of course, such a finesse would be a Whist atrocity. With King, Knave, &c., some players finesse the Knave. This is only right when you have such strength in the suit as to feel sure your partner has led a strengthening card from a short suit. It is nearly always wrong to finesse in your partner's suit. The finesse from Ace, Queen, &c., is almost the solitary exception to this rule. You should, therefore, in general play King, from King, Knave, third hand. When nine is led, and you hold King, Knave, and others, you pass the nine, if strong in trumps, and the state of the game is not critical (supposing always that second player has not covered tho nine). Otherwise, you may either finesse the Knave, or not, as you may deem best. Fourth player is as likely to hold .\ce and no other honour, as Queen and no other honour : if he holds both Ace and Queen, it is indifferent what you play ; he will, in any case, remain with an honour over you. (To be continued.) A correspondent points out what, of course, I had noticed myself, that there is a double — really a single — error in my notes to th& " Hand for Study," in No. 30. I had originally written out the hands and ]>lay from memory, being, away from my books. I sup- posed B had three tmmps, whereas in the actual game he had but two. Hence, in my notes, referring to second trick, I said B returns the highest of two cards left ; and referring to third, A leads trnmps again, though he is drawing two for one. Of course, when I saw the play of the hands, which had been taken direct from Cavendish, I recognised my mistake. But from some cause or other the necessary corrections were not made. The point of the game, however, is not affected by the mistake. Vall-e of Good Play. — A correspondent asks whether good play really counts much at Whist, and describes several tests to which ho has subjected the matter, with the result that good players have no better chance than bad ones. There is so much chance, unfortu- nately, in Whist as actually played (it might be immensely improved in this respect) that a casual observer, or one who watches play for only a few weeks, or even months, might very well suppose that bad players have quite as good a chance as the best players. But no one at aU acquainted with the game practically can doubt that in the long run good play must invariably get the better of bad play. Not a Whist evening passes but a practised player will note half-a-dozen cases or more in which tricks— sometimes two or three at once — have been lost by bad play ; while not more than one or two cases will occur during tho same time, in which bad play has, by an accident, turned out well or good play ill. Cavendish's experience should suffice — owing to its wide extent and carefully noted results — to settle this point finally and for ever. He tells us that of 30,668 rubbers played from Januar\-, 1860, to December, 1878, he won 15,648 rubbers and lost 15,020, and counting points, which tell far more, he won in all 8o,l-S6 points and lost 81,055, gaining thus a balance of 4,431 points. It is prac- tically impossible that so largo a balance in his favour should be due to mere chance. The difference must have been duo to play. Were two good players matched in as many rubbers against two bad ones, the difference would be far greater. ^uv €l)ti5 Column. By Mepihsto. VIENNA INTERNATIONAL TOURNAMENT. After tho finish of tho 20th round on Saturday, June 3, the scoro stood as follows : — Mackenzie 13i Zukertort llj I Tschigorin 8 Stoinitz isi ■ Hruby 11 Weiss 8 Mason 13 Wittek 91 Bird 7» Winawer 13 Schwarx 9 I Ware C^ Englisch 12t Meitner Si Floiasig 6 Bluckbamo 12 Paulsen 8 Dr. Noa has withdrawn from tho Tournament. From the nl)ovo score it will be seen that tho English players arc well to the fore, and we think that they will still more improve their position for final place. On Thursday, Juno 1, Blackhumc had to meet Stoinitz, and tho former won he conquering his mighty op]xinent in only twenty- seven moves. Nevertheless, Stoinitz has dniwn well, ho having reached Mackenzie's scoro, who had boon leading, by [>or«onalIy vanquishing his rival for tho time being, in their second game, which was iiluyed on Saturday, tho 3rd inst. Stcinitz's victory over Mac- kenzie will have an important influence on the final issue. Zukertort 32 • KNO^A/'LEDGE [June 9, drew with Uackenzie and Winawcr, but he defeated Mason, who is doing very well, as can be seon from the above score : — [By Telegram.'} Vienna, Tuesday night. The leading plavers are Steinitz, with 15, WiiiawerlS, Mackenzie 1 H. Mason Mi, EnglUch 13J, Blackburiie 13, Zukertort 13, Hruby 11. .Schwartz lOJ. Wittek lOJ. We surmise from the above telegram that the second game be- I ween Steinitz and Zukertort must have resulted in a draw. Problem >'o. 45, End Ga BUCK. '1 w j I ± ['\ ^__^ Mw i White to play and nin. 1. P to K7 1. R. to K I If 1. R takes B(ch), 2. R to B2 and the Pa\vn will Queen. 2. B to Q5 2. P to Kt4 White threatens mate by R to Rsq. If Black plays his B then R to Rsq(ch) and R8(ch) and Pawn Queens. 3. R to Ksq 3. R takes R 4. B to K4 and Pawn Queens and wins. fjame played : Two Knights' Defence. ■While. BlBclt. Bird. TschiKorin. 19. Q to K2 (/)Kt takes P 20. P to Kt3 Q to Bl 21. K to Kt2 (g)R to K3 22. QRtoK8q(h)QR to Knq 23. R to KUsq P to KR4 24. QRtoKBsqQ toKt3(j) 25. KttoQ8q(;0P to KG (l) 26. B to Q4(m) Kt takes BP 27. R takes Kt Q takes P (eh) P takes R P toQBl R takes Kt (n) R takes P p to R.-; P to EC White. BUtlt. Bird. Titchigoriji. 1. PtoK4 PtoK4 2. Kt to KB3 Kt to QB3 3. B to B4 Kt to B3 4. Kt to Kt5 P to Q4 5. P takes P KttoQEt ■>i. a toKt5(ch)P to BS 7. P takes P P takes P «. B to K2 P to KU3 'J. Kt to KB3 P to K3 10. Kt to K5 Q to B2 (a) 11. Kt to Kt4(6)B takes Kt 12. B lakes B B to Q3 (c) 13. P to KI13 Ca..,tle8 11. KttoQBS KttoB5 15. P to QKt3 Kt to K4 16. B toKt2(d)KR to Ksri 17. Castles Kt f K4 takes B !'>. V takes Kt Q to Q2 (e) NOTES. (i) This move ■ L'ood steady game. (h) This defence is awkward ; we prefer 11. P to KB4, B to Q3. 12. P to Qt, Castles. 13. P to B3, P to Bt. 14. Kt to R3, P to R3. 15. Kt to B2. (r) The Bishop occupies a good position on Q3 ; for tho present it hampers White's development, and prevents his Castling. (d) The Black Knight is very well placed on K4. White ought not to have hesitated any longer to withdraw his Bishop from its awkward position on KH to K2. (c, This gives Black a decided advantage. (/) An effort to save the Pawn would have been unsuccessful ; if, for instance, 19. P to B3, then Black plays B to B2, threatening Q to Q3, but if White replies to B to B2 with 20. Kt takes P, then Kt Ukei Kt. 21. P takes Kt, E takes P again, with a good game. 28. K to Bsq 29. Kt to K3 30. B to B3 31. P takes R 32. Q to Qsq 33. B to Q2 resigns (o) less attacking than Q to Q5, but it gives Black (j) A natural move ; it enables White to oppose R on Rsq, should Black piny Q to R4. {h) We should have prcferroa 22. Kt to Qsq, to bo followed by Kt to K3, or R to Rsq. QR to Ksq was not a defensive move; it would have been better to wait till the Queen's Rook was wanted ; for, as actually occurred later on, this. Rook played to Bsq, thus losing time. (i) White has, as we pointed out in our former note, uselessly lost a move with his Queen's Hook. (j) Black is playing with great tact ; he initiates an ingenious combination, based upon the po.ssibility of taking the Bishop's Pawn with tho Knight, and then winning by taking the Knight's Pawn with the Queen, as she would bo supported by the Bishop. Wo give a diagram of this interesting position : — T.M lllUDUIK. wniis. Bird. ('.) White ought to have seen the danger and played 25. R to R3- (i) Highly ingenious, if now P takes P, then Kt takes P(ch), Kt t.ikes Kt, R takes Kt, and wins. Of course, he dare not take with the Bishop's Pawm, on pain of Q takes P (mate). (hi) Although White's game is apparently hopeless, wo should even now have preferred 26. R to R3, and, if Black replied, P takes Bl', 27. Q to Q3, but it was only a question of which way to die. 26. P to KB4 would havo been mot by Black with P takes QP, 27. Q to Q3, R to K7 (ch), 28. Kt to B2, Kt to KG (ch), &c. (ii) This brings matters to a speedy termination. (o) As ho cannot escape the ingenious mate prepared by Black, for if 34. B takes R, Q to Kt7 (ch), 35. K to K2, 1> to B8 Queens, with a double check and mate. ANSWERS TO CORRESPONDENTS. •»• Please address Chess-Editor. Correct solution of Problems Nos. 43 and 44 received from Francis J. Drake, C. W. Croskey, Clarence John Watson, Sonox Solitarius, T. A. S., Borrow, Kit, IJ. A. N., U. W., J. B. of Berford, Moleque, B. G. Sergeant, Alfred B. Palmer, Leonard P. Roes, J. Bunyan, J. A. Schmucke, J. P., Ilerbort .Jacobs. No. 42 coiTcetly solved by Bronton, C. W. Croskey, J. B., and Ilerbert Jacobs. Novice. — Toll us where you stick ; wo will heli) you. G. R. — We did not consider it necessary. Kit.— In No. .351, Q to Esq., 1. P takes P, and there is no mate. ^___ NOTICES. The Finit Volume of Esowledob will be published tlii^ week, bound in red cloth, gilt lettered. Price 10«. 6d. Vol. I. will comprise tho numbers from the commcncoraont (Nov. 4, ISSl) to No. 30 (Majr 28, laH2]. As there is only a limited number of copies, the Publishers advise that orders should bo sent in without delay, to prevent disappointment. The Index to Volume I, will also bo published, price 2d., post-free 21d. Binding Cases for Volume I., price Is. 6d. each. Complete copies bound {including Title, Indel, and Caae) for Zs. 04. each. The following Monthly Parts of Khowlbdoh an II. being out of print) :— Past III.— (.Jan., 1882.) Containing four numbni Pabt IV.— (Feb., 18i2.) ' Containing four n PiUT v.— (March, 1992.) Containing Ave n Part VI.— (April, 188J.) Containing four numbers. Price lOd. Pabt VII.— (May, 16W2.) Containing four I Subscribers wish to the Publishers, to be had (Parte I. sad limbers. Price lOd. Post-free, Is. umbers. Price lOd. Post.free, 1«. Post free. Is. Zd. Post-free, Is. :e lOd. Post-free, Is. I make early appljcatioa OFFICE: 74 & 75, GREAT QUEEN STREET, LONDON, W.C. Ju.N-E 16, 1882.] ♦ KNOWLEDGE ♦ 33 iCL \ AN ILLiJ,ilR\TED ^ i^ ; ^^^ MAGA,ZlNEo?S€IENCE ^ : PLAINLY VfORJED -EXACTLY DrSCRH^}--0 LONDON: FRIDAY, JUNE 16, 1882. Contents of No. 33. 7161. The Grosrraor Galler/ 33 Enslish Seaside Heilth-Kesorts Was Ramesei II. the Pharaoh of | Alfred Uaviland the Oppression? By Amelia B. | Home Cures for Poisons F.dvanb. II.— Joseph's Place in ! June Flowers History 31, The History of Tube.-cla The Amateur Electrician — Elec- ' On Some Critics trie Generators {lUuatraUd) 35 ' Coebespoxbescs How to Get Strong 36 Answers to Correspondenta A Studv of Minute Life. By Henrv Our Mathematical Colunm J. Slack. F.G.S., F.E.MS :. 37 Our WTiist Column Conduct and Duty 3S Our Chess Columa THE GROSVENOR GALLERY. [Second Notice.] ART and science are so closely akin, and Loth are so manifestly included under the general head Know- ledge, that we need make no excuse for treating works of art from the artistic as well as from the scientific stand- point. Yet we shall not dwell further on those enormities of the (esthetic and maniac schools which are manifest at once to the artistic eye. We must, in passing, note tliat a word in excuse may l)e said for the followers of the modern MediiBval school. There is a natural temptation for those who find that, thougli eager to cover canvas, they can iieither draw nor paint, to take work in hand wlucli re- quires skill neitlier in colouring nor in drawing. " You are not pretty, my child," said a clever mother to her daughter ; " therefore, you had better be odd. It is your only chance of attracting attention." This, which is the raison cTelre of the a-sthetic school generally, is a sutfi- cient principle for the painters of that school. Any one can copy a mcdiajval picture without faults detracting from its mediaival character : a little change in an iinpos.iiblo limb does not make it less mediievally impossible ; a slight difference in some ghastly tint gives only another ghastly hue, which still remains mediajvally hideous. There- fore, if we were advising a would-be artist who could neither paint nor draw (and who was too lazy to learn) how he might obtain an ca.sy noto- riety, we should tell him to try the mediieval school. " You are too unskilful or too idh^" we might say, "to paint anything really good; therefore go in for oddity. Even i/our drawing will not spoil a mediieval figure. You know as much of perspective, linear and aerial, as the mediseval painters did (who knew nothing) ; you cannot err much more egregiously through want of talent and energy than they did through want of expe- rience. Follow, then, their school. Carefully copy all their faults. Pretend that you find in deformity beauty which others cannot see, in sickly tints a delicacy of hue which others cannot appreciate. Remembering that as there are always many foolish j>eople, you may be sure of a fol- lowing, after a fashion." In every age there have been these affectations, though we learn it, unfortunately, not from any works which have survived, for all the works of such schools have a fatal facility in fading out of view, but from occasional passages of ridicule in writings by contem- poraries who have survived. In this way the memory of even esthetic absurdities may be handed down — to an amused posterity. Of the Whistler school it need only be said that as there are some who take idiocy for eestacy, there may be a few who find genius in insanity. It would be unfair to class Mr. Paget's " Odysseus " (No. 26), with either the idiotic or the insane schools of art He has honestly and painstakingly — almost painfully — endeavoured to work out a certain idea : only, unfortunately, the idea was not altogether a good one, or what was good in it only a very great artist could effectively educe. Ulysses steering towards the setting sun, his body illumi- nated by the rays of the sinking orb, a dark purple gloom gathering over the mountains behind, broken only here and there by touches of ruddy light — this were a subject, indeed, for a noble painting. How finely might the worn but reso- lute face of the wanderer be presented, sadness and courage contending over it even as the gloom and glory of sunset were contending on sky and sea and mountain height ! In such a work a great painter would not have suffered the thoughts to be distracted from the poetry of the main idea by trivial accessories. He would not (appa- rently for no other purpose) have added to the artistic difficulties of his subject, by endeavouring to do what no artist has ever yet done successfully in ideal painting, — to represent, namely, one half only of a boat (in other words, to present the picture from an impossible point of view). It is this which :Mr. Paget has done, and herein, we conceive, began the difficulties which led to this picture becoming a rather painful failure instead of a decided success, as it might have been if the artist had not overweighted himself with difficulties. Albeit tlie hero's face is hopelessly coarse and commonplace ; and in a scien- tific sense we must object to the head which Mr. Paget has assigned to the man of keenest intellect and widest expe- rience among the heroes who fought before Troy : Ajax Telamon rather than Ulysses is here depicted. If we had not known that Mr. Holman Hunt can paint, and paint well, we should not have discovered it from the ridiculous picture which he has chosen to call " Miss Flamborough." Ill conceived, ill drawni, and worse painted, it is utterly unworthy of him. Mr. Muybridge lias, we believe, left England for Ame- rica. We trust he did not, before he went, observe Mr. Clarke's picture " Labour " (No. 38), with its impossible horses, or Mr. Barclay's "Early Steps" (No. 43), with its very singular calf. " Flora," in No. 47 (R. W. Macbeth), ought, if she were wise, to get rid as quickly as possible of those hounds, whose villanous faces accord ill witli their ridiculous shapes. The " Release of Prometheus by Hercules" (No. 57, by Mr. Richmond), and the "Entombment" (No. 51, by Julian Story), are pretentious but ill executed attempts, a very long way " after the " great master whose style is aped. Of Mr. Richmond's portrait of Mr. Gladstone (No. 77), it were well to say nothing, since nothing good can he said. But there are some excellent porti-aits by Mr. Richmond, showing that if he has painU'd Gladstone so tliat the Premier's worst enemies must feel a touch of sympathy for him, he can do what is very gooil when not over taxed by the wish to do something very great The finest portrait, however, in the Gi-osvenor collection this year is among the sculptures, Mr. E. Roscoe MuUius's bust of the Rev. Stopford Brooke (No. 368). Wo do not 34 • KNOWLEDGE <> [Jdne 16, 1882. rfmeiubor to have seen for many years a sculptured portrait »o full of character. Compare this work with another by the same sculptor — the bust of Mr. Shaw in the Eoyal Academy — and it will be seen that as wide a range of character can be covered in sculpture as in the sister art, and that sculpture is admirably suited (in skilful hands) for the delineation of subtle 'shades of character. Tluit Mr. MuUins should have succeeded in indicating intellec- tual power in one bust, and business capacity in the other, is, of course, little. But he shows the precise quality of the intellect in one case ; in the other the special character of the aptitude for business. TVAS RAMESES 11. THE PHARAOH OF THE OPPRESSION? Ev Ameli.\ B. Edwards. II.— JOSEPHS PLACE IN HISTORY. MDE ROUGE'S argument, steering clear of chrono- • logy, hinges principally upon the name of the " treasure-city " built for Pharaoh by the Israelites ; but this argument, strong as it is, would be greatly strength- ened if we could show a distinct correspondence between the space of time assigned to the Hebrew sojourn and the space of time which divides Joseph from Rameses II. Before any such test can be applied, it is, however, essential that we endeavour to find out as nearly as possible under what Fliaraoh Joseph rose to power. Now, the time of the sojourn in Egypt is expressly stated at 430 years (Exodus, chap, xii., verses 40 and 41), and the age of Moses at the time of his return from Midian (not at the time of the Exodus from Egypt, as M. do Roug6 puts it) is as expressly stated to have been eighty years (Exodus, chap, vii., verse 7). To those who know not the chronological pitfalls which enliven the paths of Egyptology, it may pro- babl}' seem that nothing would be easier than to allow eighty years for the age of Moses, and thence, by a retro- grade calculation of 4. '50 years, to arrive at the Pharaoh of Joseph. The method is doubtless excellent ; and if by counting back 4.30 years from Mr. Gladstone's return to office in 1880, we sought to determine under whose reign Jack Cade made himself master of London, it would answer the purpose quite satisfactorily. But not thus can we go to work when dealing with Moses and the Pharaohs. It is not possible, indeed, to apply ordinary chrono- logical methods to inquiries concenn'ng early Heljrew or Egyptiin history, because neither the Hebrews nor the Egjptians had any fixed era from which to reckon. Neither had they any exact system of reckoning. The Hebrews counted by generation.? — that is to say, by a rough-and-ready system of averages. The Egyptians counted Vjy the regnal years of the Pharaolis, and these regnal years were liable to much miscalculation. Some- times an old king shared the throne with his heir during the latter part of hi.'? reign ; and in many cases a Pharaoh began by reigning with his father and ended by reigning with his son. Rami'ses II., for instance, with whom we are now especially concerned, reigned as Pharaoh- Coadjutor during the latter years of Seti I., and himself resigned the c^res of government to liis successor, Menephthah, twelve years before liis death. Again, a king's reign was soraetiraes counted from the beginning of the year in which his predecessor died, and sometimes from the day of his own coronation. Nor do the possibilities of confusion end here. All dynasties were not legitimate, or . even successive ; and not merely certain Pharaohs, but whole lines of Pharaohs, were consequently passed over by conservative liistorians, as though they had never existed. There are, in fact, very few even approximately certain dates in Egyptian history before the period of the XXV Ith dynasty, and those few (among which !Mr. R. A. Proctor's astronomical date for the building of the Great Pyramid must henceforth occupy a foremost place) can only be regarded as landmarks planted here and there in a wide waste of uncertainty. Granted, then, the impossibility of conducting our present inquiry upon a purely chronological basis, we are reduced, firstly, to the evidence of tradition ; and secondly, to tlio internal evidence of the text According to the evidence of tradition as lianded down by two early Christian writers (Eusebius, a.d. 300, and (ieorge the Syncellus, A.D. 800), Joseph was sold into slavery at a time when Lower Egypt, and possibly the whole of Egypt, was occupied by a race of foreign invaders known as the Hykshos, or Shepherds. The nationality of the Hykshos is not exactly determined. Wo only know that they were predatory tribes of Asiatic origin (probably Syrian and Sinaitic), and that towards the close of the XlVth dynasty they descended on the land in vast hordes, slaying, ravaging, and confiscating all before them. Their rule extended over three dynasties, namely the XVth, XVIth, and XVIIth, and is supposed to have lasted for five hundred years. The native princes, meanwhile, were driven southwards, and some would seem to have ruled as tributary chieftains at Thebes. The name " Hykshos " is sup- t y j "^ 1 tji\ *-& posed to bo derived from //y^•, iii^ m + JT i li " ruler," and Shasu, " shepherd," ^^ . . a . Su or plunderer; Shasit,* being a Thcso liicroglypha arc: — word used in a general sense to 1- •*• '''l'° Ka''le"i P™- denote the tribes of the Eastern ^°°^^'"l^''- 2. Ancagloj . .. 1 J, , . a. 3. A young shoot ; Su. frontier; and thereby seeming 4. A chick ; u, being a con- to indicate that the Hykshos firmatioii of Iho vowel- were originally tent-dwellers and sound. 5. A man signify- herdsmen, like the wandering ing the general Bonsoottho •r> , « t r ii i word. 0. Ihreo upright Bedawcen Arabs of the present ,t,„t^„_ „,^„i„g ., ,^^„^y . day. Abrahams visit to Egypt or a noun of nambor. probably took place during the reign of some Ilykshos king of the XVth dynasty ; while Joseph is traditionally said to have flourished towards the clo.se of the XVIIth. This, the last Hykshos dynasty, was governed, in the opinion of the late Mariette Pasha, by kings of Hittitc nationality. It is, at all events, a singular and a significant fact that Set, or Sutekh, the great god of the Hykshos, was also the god of the Hittites. We will now turn from tradition to the internal evidence of the text. I need not recapitulate the beautiful and affecting story of Josepli — a story in which every touch of local colour, whether as regards names, customs, or incidents, will bear the strictest arch;eological scrutiny. For our present purpose, I need only quote Joseph's instructions to his brethren, before he introduces them to Pharaoh : — " I will go up," he says, " and show Pharaoh, and say unto him. My brethren and my father's house {i.e., house- hold), wliich were in the land of Canaan, are come unto me ; " And the men are shepherds, for their trade hath been to feed cattle ; and they have brought their flocks, and their herds, and all that they have. * Tlio AbbiS Vigoareux has pointed out how tho Ilobrow root ^DV/, sU'ih, or DDIff, hUm, " to dovaatate," "to pillage," is used in tlio Bible to designate tho forays of tlio Bedawcen hoathtn. Sco " La Biblo et leg Ddcoavertes Uodemos," vol. ii., p. 86. 18H2. Junk • KNOWLEDGE • 35 " And it shall come to pass, -when Pharaoh shall call }0u, and shall say, What is your occupation t " That ye shall say. Thy servants' trade hath been about cattle from our youth even till now, both \vc, and also our fathers : that ye may dwell in tlie land of Goshen ; /or every shepherd is an abominntion unlo the E'jyptians." (Genesis, Chap, xlvi., verses 31, 32, 33, 34.) In accordance with these instructions, we presently find them saying to Pharaoh : — " Thy servants are shepherds, both we, and also our fathers ; " to which statement Pharaoh replies by making them welcome, and assigning " the best of the land " for their place of dwelling.'' Now it is hereby evident that if to be a shepherd (" Shasu ") was an abomination to the Egyptians, it was a recommendation to Pharaoh. That the name should be hateful to the conquered race was inevitable ; and although the invaders had become so thoroughly naturalised that they now ruled in all respects after the manner of the native Pharaohs, it was impossible that the Egyptians should forget the horrors of the past But to one of Sha^-u origin that name would be dear and h )noured. And it would convey a sense corresponding to "son of the desert," rather than to " shepherd," or " plun- derer." Also it would imply a Semitic, and therefore, in this case, a common ancestry. Granted that Joseph was the favourite minister of a Ilykshos ruler, he could have given his brethren no better advice than when he bade them tell Pharaoh that they came from the land of Canaan, and had been shepherds from their youth. Just so might a poor laird from Roxburgh or Dumfries, who had risen to office under James I., counsel his raw kinsfolk from the northern side of the Cheviots. If King Jamie questioned them, they must surely tell him they were Lowland Scots, and as such had played their part in many a border fray ; and this notwithstanding that a Lowland Scot was an abomination to the English. The Percys and the Stanleys would, it is true, despise them for cattle-stealing barbarians; but to be a Lowland Scot was a sure passport to the favour of the king. Tlie internal evidence of the text confirms, in short, the evidence of tradition, and shows that the Pharaoh of Joseph can have been none other than a Hykshos. (To le conlin\ud.) THE AMATEUR ELECTRICIAN. ELECTKIC GENEUATORS {continued). rrillE simplest device for collecting the current from the X revolving armature is to have two upright springs, S S' (fig. 10), metallically connected to the terminals or binding- screws, T T. With the commutator in the position illus- trated, the current piusses from the brass sections, A P>, the circuit being completed tlirougli whatever apparatus may be connected to T T". When the armature has performed a quarter of a revolution— that is to say, when the sections 0 D are in contact with S S' the circuit is disconnected, and accordingly no current is passing. This lasts, however, for a very brief space of time, and is not noticeable. Where this plan is adopted, A B must be fixed to the ebonite in such a way that wlien in contact with the springs the armature shall be in the position illus- trated in fig. Ct (KNowLEDfJK, May I'l)). A more satis factory plan, however, and one tliat will lend itself to modifications in the general details of the machine, is to employ what may be called a "rocker." Fig. 11 will illustrate it R R is a part of a brass ring, not less than an eighth of an inch tliick, and about lialf an inch wide. A slot is cut in the ring at E, about half an inch long, a screw holding it firmly to the ba.?e plate Caps of ebonit* or such like insulating material (F F) are fixed to the ends of the rocker, and thin strips of brass (K K) on to the surfaces of the caps. Similar strips of brass (L L) are i T F.-g. 10. attached by the thumb-screws to K K. Between these pairs of brass strips or plates, the copper brushes (M II) are clamped. They are simply strips of sheet copper, cut for about half their length, so as to present the appear- ance of combs, with verj- close, but rather broad, teeth. The ebonite should, for various reasons, be of larger section than the rocker (say one inch by three-eighths to a half) while the surfaces should be inclined at such an angle as to make the distance between the brushes a little less than 1{ in., both inclinations being at tlic same angle, one inwards, the other outwards. Care must l>o taken that the clHinitr efl. ctually insulates the brushes from tlio rocker; spiral springs (made by winding ratlier stout copper wire round a pencil) being u.sed to connect the brushes to the terminals TT. In tlie diagram, the brass plates arc drawn slightly awny 86 • KNOWLEDGE [June 1G, f.-jm the el>onite caps for the sake of clearness. The olyect o! the slot (E) ia to allow of the alteration of the point of contact between the hnishes and the coninintator— a jiecessary feature, as will lio seen by experience. One of the most important points in connection with an dectrie generator is the motive power. This may take the Torm of a treadle or an ordinary niultiplyin-^ wheel turned by hand. To a great extent, we must leave the arrange- ment of this matter with the experimentalist ; but the wheel should be as far as possible from the armature, say 18 inches, tiie wooden base, where a multiplying wheel is used, being about 14 inches by -21 inches. It may be pointed out, however, that the" width is not necessarily the same throughout. Owing to the sinallness of the armature pulley-wheel, an endless gut-band is requisite, but some arrangement to compensate for its stretching ia essential. Fig. 12 illustrates a simple device ; D repre-sents a standard 1 inch thick, if of wood, h an inch if of metal, through which passes a shaft A B, of the section .shown, cut from a live-eighth rod to half-an- inch in diameter at each end. It is provided with a screw thread at the extremity A, and a slot like that on a screw- head at B, a pin (C) being driven through to hold alight metal or wooden wheel (OG) 9 to 12 in. in diameter, in position, surticient freedom being allowed for the wheel to revolve easily. E is a nut, .screwed on at A, to pull AB tight up to the bo.s.s F. On first adjusting the band, the end (I{) of the shaft should be turned towards the machine. As tlie band stretches, B should be gradually turnc'd towards the remote side, thus increasing finally the distance Ijotwct'n the centres of tlie wheel and the armature by a ■<|uarter of an inch. \\' now TO GET STRONG. (Conlimu;rI.) TE have first to notice that it is by no means neces- sary, as many imagine, to give much time daily to l)r(i\((l by ancient physicians. Fencing, single-stick, and oilier such encounters are good, if entered upon with due niudcnition, both as to time and as to the spirit with which they are carried on. First and foremost in all exercises comes the develop- ment of the chest, because this development means the increase of lung-power and heart-power, improvement in the breathing, and in the circulation. Scarce one in a hundred among men in middle life has his breathing apparatus in respectable ordci'. A man in good health ought to be able to run a mile at a moderate pace without inconvenience. But how many can do this? We do not invite paterfamilias to try the experiment, unless he is prepared to stoja tin* trial so soon as he is satisfied that he cannot run the mile vnfhout inconvenieiu-e. For there; is ■Janger in the experiment, if the question is whether, by sheer endurance, ho can get through thi; mile at any pace resembling a run. Let any man, even as young as twenty- fi\e or thirty, who has let day after day pass for several years without duly exercising his chest, content himself by running until it would be distressing to him to continue the exercise : he will vciry quickly recognise how much beyond his power running a mile, without distress, has become,— entirely through his neglect of daily exercise. Not a day should be allowed to pass without exerci.se by which— at least three times each day— every air-cell of the lungs has been filled to its utmost capacity. Once, at least, each day this should be done by active exertion, such as a sharp, but not distressing, run, increasing gradually until two or thn^r; hundred yards are covered at full speed, or from half a mile to a mile at a steady swing. But any run long enough to set the lung bellows actively at work will suffice for this purpose. Instead of running, however, some may prefer sparring. This is capital exercise for the chest, and is good also for the arms and shoulders. A live opponent is not needed— in fact, i-s not desirable ; for where there is one the exercise is apt to be continued too long, JuxE IG, 1882.] KNOWLEDGE 37 and repeated only intermittently, whereas it should be carried on daily, and for a limited time only. A calf-skin bag, fourteen or fifteen inches in diameter, hung by a stout cord from the ceiling (if there is a beam to it, or from a cord stretched between two high nails on opposite sides of the room), will make a capital dumb boxer. The bag should hang at about the height of the chin, so that its highest part is opposite the eyes and its lowest part opposite the chest. Pound away at this as if it were the head and shoulders of a living opponent Hit out from the shoulder so that it Hies up to the ceiling ; catch it " a good one " as it flies back towards you ; advance a step, and hit it so that at the next rebound it flies over your head ; spring sharply round, and meet it on that side ; hit it upwards till the cord loops ; hit it round arm, so that if you are not quick enough, it catches you on the back of the head. In five minutes' time, (which, later, you may extend to ten), you will be pulling and panting like the conventional grampus. You can then rest, or turn to some other less active exercise among those to be hereafter described. But there is an excellent and too much neglected exercise for the chest which requires no apparatus at all, and can be taken without leaving your room, or even your seat It is simply the steady inhaling of air (at the nostrils) until the lungs are fully distended, holding the air there for a while, and then slowly expelling it. A time- keeper is useful with this exercise, so that its effect in improving the capacity of the lungs and increasing tlie power of the breathing apparatus generally, may be tested. In a capital little book, by Sir. W. F.lackie, bearing the same title as this series of papers, the following case, illus- trating the good effects of a practice in effect identical with this, is cited : — "Some years ago. Dr. G., of Boston, showed us a photograph of himself taken several years previously. The shoulders were warped forward, the chest looked flat, almost hollow, and the face and general appearance sug- gested a delicate man. He was inclined, he said, to be consumptive. Well, by practising breathing (not in an ordinary ' blowing machine,' where you empty your lungs of about all that is in them, but an inspirometer, from which, instead, you inhale every inch of air you can), and by practising vigorous working of his diaphragm, he had so expanded his lungs that he could inhale three hundred and eighty cubic inches of air at one breath ! Certainly, the depth of his chest at the later period was something astounding, it being, as nearly as we could judge without calipers, fully fourteen inches thi-ough, directly from breast- bone to spine, while it was a strikingly broad chest as well. An even more astonishing feature was the tremendous power of his voice. He said he could run two blocks (nearly a tenth of a mile) at one breath." Tins case maj-, of course, be exceptional, still it is ex- tremely significant. {To he continued.) A STUDY OF MINUTE LIKE. Bv Henry J. Slack, F.G.S., F.R.M.S. GREAT interest is felt in the history of minute living organisms, called microferments, on account of the discoveries by Pasteur, and others, showing their action in the production of various diseases aflliiting domestic animals and mankind, and in many cases indicating how the mischief may be prevented. These bodies are related to the lower fungi — moulds, and so forth — and as they feed upon moist organic compounds, they assimilate certain of their elements for their own use and growth, and cause, or leave, the rest to reconstitute themselves in simpler forms. If this sounds too complicated to be easily intelligible, a few instances will make the principle clear, chemical formula; and figures being avoided, because, although they are extremely useful to those accustomed to their appearance, they perplex beginners. All living creatures are composed of highly complex materials, and life processes are only carried on in the presence of sufficient moisture to give mobility to their particles. Sugars, fats, and starches are examples of one group of these substance?, and white of egg or albumen represents another group. Chemists find cane sugar to be made up of a gi-eat number of particles — atoms— of carbon, hydrogen, and oxygen ; and it is never quite free from other matters. Carbon, hydrogen, and oxygen are ranged amongst the simple substances, or "elements;" but this means no more than that no one has succeeded in resolving them into simpler constituents. However this may ulti- mately be settled, they, like other bodies in the " simple " list, combine in definite proportions, and the smallest portion capable of so doing is commonly called an atom, and has a definite weight distinguishing it from an atom of anything else. Hydrogen being the lightest known sub- stance, is taken by chemists as their standard, and the atomic weight of a body is stated in comparison with that of hydrogen. Thus, reckoning an hydrogen atom as weighing 1, an atom of oxygen weighs 16, and one of carbon 6. The reader will exclaim, " What has this to do with microferments and yeast 1 Wait a bit and see. Sugar is built up of a multitude of the combining par- ticles of carbon, hydrogen, and oxygen ; twelve of the first, twenty-two of the second, and eleven of the third go to make the smallest possible piece of cane sugar. Now, just imagine what a complicated pattern can l>c made with forty-five balls, and when one pattern containing all of them is broken up, how many simpler patterns may be made by unions of balls in twos, threes, and all sorts of numbers. When cane sugar is dissolved in water, besides its own forty-five particles, there are its water particles, two of hydrogen and one of oxygen. The minutest drop of the solution, therefore, consists of forty-eight particles, and when living yeast is put into it and feeds upon it, a great disturbance takes place amongst them. If a small portion of brewers' yeast, or the so-called German yeast — so much used by bakers, and which comes over from Dutch distilleries in a putty like mass — is placed on a glass slide in a drop of water and viewed with the microscope and a power of about 400 linear magnifi- cation, it is seen to be composed of little tiny bl.idders, more or less round. It woiild take from two and a half to three thou.';and of these little cells placed in a row to make up one inch in length. Each one is, however, a minute plant, capable of carrying out a complete cycle of vital processes if the appropriate conditions are provided. Brcwera' yeast is the best to experiment with, as the cells are rather larger, and at a summer temjierature grow very quickly. The common brewers' yeast rises to the top of the fluid it causes to ferment i" consequence of the rapid formation of carbonic acid gas bubbles which buoy it up. In (lorman breweries, a slower process, at a lower trnipcrnturo, is carried on, and the yeast falls to the bottom of the fermenting vessels. Supposing the reader takes up as much yeast as equals a pin's head in size, puts it in a small cell with sugar and water under the microscope, and keeps it in a warm room ; some of the little bubbles will soon swell, smaller bladders will grow KNOWLEDGE • [JoNE 16, 1882. out from them, and finally separate. Under favourable conditions, Uiis process goes on so Lxst that scores of the little plants soon become thousands, and the thousands millions and billions by this simple method of rapid budding. Many of the higher plants, besides propagating by seeds, which result from the cooperation of male and female organs, also multiply by buds. Some of the begonias exemplify this in a striking way, and there is a lily, common in gardens (bulhi/ennii), which produces black bulbils all up iu st<:-m. The yeast plants are not, therefore, excep- tional in the budding process, and their mode of nutrition is found to be the same in principle as that of the higher vegetation. The yeast plants are capal)le of taking oxygen from the air, if in contact with it, or, as tish do, from air dissolved in w.iter ; but when they cannot get enough this way, they supply themselves by decomposing the sugar in the solutions of malt or other saccharine materials they are employed to ferment. M. Pasteur says : " Fermentation by yeast, the type of all ferments properly so-called, presents to us the direct consequenco of the work of nutrition, assimilation — in one word, of life — effectuated without free oxygen. The heat consumed in this work must necessarily be obtained in the decomposition of the fermentable matter, that is to say of the sugar, which, after the manner of explosive sub- stances, disengages heat in its decomposition. Fermenta- tion by yeast appears thus essentially allied with the power of this small cellular plant to perform a kind of breathing ■with the oxygen combined in sugar." Other plant-cells induced to live under similar conditions arc found to be provocative of fermentation. In alcoholic fermentations of eitlicr wine or beer, there are other matters present besides the saccharine ones. Some of these belong to the albuminous class, and besides carbon, hydrogen, nitrogen, and oxygen, they contain sulphur and phosphorus, and these, though in small proportions, contribute to the mobility and insta- bility of the wine-must or sweet-wort of the beer. The fermentiible fluids also contain some mineral matters which the great plants re<|uire, as do the higher kinds of vegetation, for their perfect growth. The respiratory acts of plants consume oxygen and lead to the evolution of carbonic acid. Their nutritive acts include the digestion of carbonic acid and the evolution of oxygen, which produces a slow combustion, and when this proc<»-S3 is carried on l)y the microferments, fungi, obliquely they do so, as between the tropics and the poles, the more is the amount of heat diminished. A ray from the sun falling p-rpendicularly on an object covers the least surface, and imparts the most heat ; whilst a ray falling obliciuely covers a larger surface, and gives less heat in proportion to its obliciuity. Moreover, a sun- ray that falls perpendicularly on the earth piu'aes through a lesser thickness of atmosphere, is shorter, in fact, than one which falls obliquely, and therefore loses less lieat in passing through the atmosphere. In using a magnifying glass for lighting a match wo make use of this knowledge, and incline the glass at such an angle as to receive the sun's ray-s as it were, per- pendicularly to its surface, and then focus them. Agoiji, if a ray of sunlight be admitted through a liole in a shutter, and a piece of white cardboard be held at such an angle as to receive it perjiendicularly, it will be fouml that the space occupied by the light ."spot will have as small an area as j)0S- sible according to the distance ; wliereos when the paper is luld so as to receive this sun ray obliquely, the area covered by the light is increased in proportion to the ob- liquity with whidi the ray falls on the surface. Tlie dia- grams showing the apjmrent i>ath of the sun during April and May, published in Vol. 1. of Knowlkdck, pp. 469, OS?, are not only interesting and instructive, but will help the student to understand how in our latitudes the oV)liquity of 40 KNOV/LEDGE ♦ [June 16, 1882. the sun's rays is increased or diminished according to the seasons. The effect of this obliquity on tlie mean tempera- ture of tlie air will be seen by comparing the following mean temperatures within the different latitudes which cross England. We have taken the observations made in 1881 as illustrations. Between tlie parallels of latitude 50° and 51° N. there was no large town included, so that the figures really represent the mean air temperature of the South coast :— M»«n Air Mc»n Air Latusdo N. Tomporaturc. S('4siJo Temperature. Fahirnheit. Tow-ns. Fahrenheit. Between 50° and 51° 49° 1' South Coast 49° 1' 51° „ 52° 48° 1' Barnstaple 50° 5' 52° „ 53° 46° 9' Lowestoft 47° C 53° „ 54° 46° 4' Llandudno 48° 6' „ 54° „ 55° 45° 4' Scarborough 47° 2' "We have selected the above sea-side health resorts as good representatives of each of the interlatitudinal belts given above for the sake of comparing their mean air tempera- tures with those derived from the forty-three inland and coast stations where the observations were made which form the liasis of the above results. A glance at the above figures will at once demonstrate how mucli higher the mean temperature of the air is for cacli latitude along the coast than the mean of England and Wales, which, of course, includes the mean temperatures of both inland and coast stations. Another fact connected with the obliquity of the sun's rays according to latitude is tlie postponemcni of the time at which the hottest and coldest periods of the days and the sea.sons take place. In all latitudes the hour of greatest daily warmth follows at certain intervals that of the greatest solar elevation, viz., noon ; for instance, at Plymouth (about 50° 23' N.) the warmest hour of the day in the sliade is at one p.m., or rather a little after that hour ;* at York (about 53° 52' N.) it is about two p.m. ; and at Leith + (a little south of 56° N.) it is 2.40 p.m.; so that the hour of greatest heat takes place nearly 1 hour and 40 minutes later in lat. 56" N. than it does at 50° 23' N. We shall find in the sequel that large masses of elevated land and the sea operate powerfully in modifying the effect of latitude on the mean temperature. This, to a certain extent, has already been shown in the table above. To illustrate the postponement of the effect of summer and winter on large masses of elevated matter we may instance the experiments made at York Minster, and recorded by John Phillips, F.R.S., in his charming and interesting work on the rivers, mountains, and sea-coast of Yorkshire. He tells us that a series of daily observations were made and continued for three years within the inte- rior of the cathedral, and showed that the hottest day is about Jive u-eeks after the summer solstice, or a forlniijhl after the hottest day in the open air ; and the coldest day five jr>;eki after thf; winter solstice, or & forlniyhl after the coldest day in the open air. We shall have to refer to the storage of heat by elevated mas-ses, such as isolat*^!! hills, and liill ranges in the neigh- bourhood of certain seaside health-resorts, and the effect, in postponing sea-son.s, the giving up of this heat produces, later on ; but a fact M-hich bears on this subject should be recorded and rememl)ered. Mf«srs. Quetelet and Forbes made a series of experi- ments in Scotland, France, Belgium, and Germany on the postyKjnement of the effect of summer and winter below the surface of the ground. It was found that the middle of SirVV. HarriB, "Rep. of Brit. Assoc., 1839." ir D. Brewster in " Edin. Phil. Transactions." summer and winter, or the extremes of heat and cold occur : — At the surface, in July and January ; 3 ft. deep in August and February ; 12 ft. deep in October and April ; 24 ft. deep in December and June, and at less than 100 ft. in July and January of the following year. So that within 100 ft. from the surface, the seasons are as much re\ersed as at the antipodes. These facts relative to the postponement of the hot and cold periods agree with the old doggerel proverbs, "As the day lengthens the cold strengthens," and " The days grow hotter as they grow shorter." We shall refer to this subject again when discussing the causes, of the local climates of the several health-resorts. In our next we shall discuss the effect of latitude on the dailij, rawjc of temperulurc. HOME CURES FOR POISONS. I^HE use of copper vessels for preparing food has led t» many cases of poisoning, though, as a matter of fact, if copper utensils are carefully cleaned, and food which has been cooked in them is not allowed to stand in them till cooled, they may be used safely enough. This, how- ever, ought not to be left to the care of servants, who, not taking scientific views of such matters, find it diflicult to understand how the utensil which was clean when food was put into it to be cooked, may bo (chemically)- unclean when the food is taken out of it. To this must be added that copper vessels, however clean, are not fit utensils for cooking or keeping any food of an acid nature. The practice of putting- copper coins into pickles to give them a pretty green colour used to be considered by some house- keepers of former times a rather clever thing. This colour was derived from the verdigris (or subacetate of copper), formed by the combination of acetic acid and the oxide of copper — and it is hardly necessary to say that verdigris is- a poison ; but the green of the pickles was very pleasant to- look at. Probably, now that copper coins are scarce, the practice of adding copper in this cheerful manner, to poison our pickles, is not .so common as it used to be. It should be added that tinning the interior of co])pers is only a pro- tection so long as the tinning remains entire. Arseniate of copper (Scheele's green, or mineral green), is formed from the combination of arsenious acid with oxide of copper. Sulphate of copper (l)lue vitriol, blue copperas, or blue-stone) is made in largo quantities fop- dyeing and colouring purposes. It is not very likely to be- taken by accident, as it has a most unpleasant metallic taste. Sy.mptoms. The symptoms of poisoning by any of the salts of copper are vomiting, violent colic, convulsive movement of head,, metallic taste in the mouth, pains in the thighs, h^g cramps, laboured breathing, followed by lethargy. Jiut sometimes lethargy and partial insensibility are among the first, symptoms noted, the symptoms of irritation coming later.. Yellowness of the skin, as in jaundice, is a characteristic feature of poisoning by copper, at least so far as metallic poisons are concerned. In some cases, slow poisoning by copper occurs, where copper ves.sels, for instance, are used daily with insufficieilt precautions. In these cases death often follows; and it is then found, in poHl-morlnm examinai- tion, that copper has accumulated in the liver. Home Remediks. In cases of copper poisoning, the vomiting caused by the poison sliould be encouraged by copious draughts of tepid r June 16, 1882.] • KNOWLEDGE 41 WEATHER CHARTS FOR WEEK ENDING SUNDAY, JUNE 11. Sunday, 4th. Monday, oth. Tuesday, Cth Wkdnesday, 7th. Thursday, Sth. Friday, 9th. Saturday, IOth. Sunday, 11th. In the above charts Iho dotted lines are "isobars," or linos of equal barometrical pressure, the vahies which they indicate being- given in figures at the end, thus- — 30-1. The shade temperature is given in tignres for several places on the coast, and the weather is recorded in words. The arrows fly with the wind, the force of which is shown by the number of barbs and feathers, thus : — ^ , light ; >, fresh or strong j ■> > , a gale ; » > , a violent gale ; 0 signifies calm. The state of the sea is noted in capital letters. The • denotes the various stations. The hour for which each chart is di-awu is 6 p.m. water, in which much suf;ar ha-s been dissolved. Afterwards ■whites of eggs dissolved in water, six to the half-pint, shojld bo freely administered. Milk or wheat Hour may be put in the water if tliere are no eggs in the house. Sugar may be added to whatever draughts are thus taken, and everything acid, especially vinegar, is to be avoided. The time between sending for a doctor (wliich should be done at once) and awaiting his arrival, can hardly be better employed than in following the above instructions. JUNE FLOWERS. Bt Grant Allen. JUKE is the botanist's despair: there are so many beautiful plants in blossom, that he can never hope to examine them all at once. The only possible plan for liim is to specinliso himself, and take a few families at a time each year. The pea flowers are a good group to study in Junoj they are recognisable at once by their peculiar blossoms, which even the unlearned know at sight and they are full of varied interest from every jioint of view- Among smaller herbs of this class, the simplest division is into those with trefoil foliage, like the clovers, and those with leaves of various other types. The medicks (Mrdicajo) belong to the tirst- named group. The only common kinds in England have emali yellow flowers, and all may readily bo known by tlieir curved spiral pods. M. lupulina, nonsuch, has but ono twist to the pml, and a single seed ; it grows abundantly in meadows. In .V. macutala tho pod has three or four tight whorls, and becomes almost globular as it ripens ; its edge is furrowed, anil lined with close pricklt>s. il. denliftilata is a rarer plant, found chiefly in tbe eastern ctmnties and on the south coast ; its \tmi has also prickles, but is not furrowed, and the whorls aro loose, like a corkscrtjw, instead of being tightly curled together, like a snail, ^fc^ilotu^ has also trefoil leaves, pecu- liarly thick and jointed at the point of union ; its long and hand- some liioso bunch of bright yellow flowers at once distinguiahcs it from tho clovers, while its small straight [mxI .separates it immediately from tho medicks. Only ono species is likely to be found by beginners, and that is M. ojffieinali.i, with a net-veined pod. J/. Arvcngi», almost confined to eastern Kngland, has tho jxxl simply wrinkled, while tho rare U. alba may bo clearly known by ila white 42 ♦ KNOWLEDGE ♦ [June 16, 1882. blossoms. The clovers (Tri/o!iiim) arc a more ditfioult Bot of pea- flowere. They are distinguished by their clustered roundish heads, strai^'ht, small pods, and often tubular flowers; but, amonj^ them- selves, the differences are very minute. Everybody knows common red or purple clover, however (T. pratense), as well as the little cream-coloured Dutch clover (T. repens), and these must bo taken as fixed )>oiuts for determining the others. Tlio beautiful crimson clover (r. incarnatinn), grown in great fields of brilliant colour, is also familiar to almost all of us. Very near purple clover come three other rarer sorts: T. muri'd'miini, with heads of the same type but much smaller flowers, and rigid, stiff calyx teeth (the lowest larger than the others) enlarged after flowering. T. sfriulum, a little shabby creeping plant, with calyx-teeth shaped like a pin's point; and T. scabrnm, which is T. marilimum much dwarfed, and trailing along tho ground. Nearer to Dutch clover arc T. hybridum, with rather pinker blo5soms, and no rootlets on the stem, as well as tho curious T. stilterraneum, whicli buries its own S3ed in tho ground, and which may be known by its reduced number of flowers — seldom more than three in tho head — as well as by its abor- tive central blossoms, which only grow out after the pods begin to swell, looking then like little hard-pointed knobs in the middle of the cluster. A totally different modification of the clover type is represented by hop-clover (T. procunibeiis), which may at once bo discriminated by its likeness to a hop : it has numerous small yellow flowers, turned back upon the stalk as it fades, and forming a sort of brown ball. T. mnii/s is the same type dwarfed, with only some twenty flowers in each head, instead of fifty, or thereabouts, as in the larger form. The only other clovers you are likely to find at present are T. arviiise, easily known by its fluffy, downy, purplish-grey head, made soft as wool by the feathery teeth of the calyx, and T. fratji- /erum, a close relative of Dutch clover, but looking rather like a strawberry as it fades. Tho remaining species are very local. Lotus corniculatus belongs to a falsely trifoliate genus, for though its leaves look like trefoils, there are really two more leaflets at tho base of each footstalk, easily overlooked unless you are warned about them. Its bright yellow flowers, with a sharp, pointed keel, are known to everybody everywhere. Rest-harrow (Ononis arvensis) has usually trefoil leaves, but sometimes tho side leaflets don't grow ; it may bo recognised by its pink, sweet-pea flower and its |)ointcd keel. The other herbs of the pea tribe have several leaflets, or at least have not trefoil foliage. Lady's fingers (Anthyllts vulneraria) may reatlily bo known by their woolly, fluffy, weedy-looking heads of yellow blossoms, with a leaf luidt-r each head. Sainfoin (Onohiychia sativa) has a long and handsome spike of pitjk and white-streaked flowers, and no ten- drils to the leaves. In the vetches and peas there are almost always tendrils at the end of tho leaf-stalks, though sometimes they are reduced to a fine (loint liko tho end of a needle. Only three vetches arc now common — Vicia sepiutn, with a bunch of purple flowers, each without a soparato stalk ; V. sativa, with solitary red flowers ; and V. cracca, with a handsome spike of variegated blossoms on long stems. They may all be discriminated from the peas by their nnmerons small leaflets. In the true peas (Lalhyrus), on the other hand, tho leaflets arc usually few and large ; as in L. pratenai; with its short bunch of pale yellow flowers. In two rarer instances, however, there arc no leaflets at all ; L. Si-e'Aia, the grass pea, has tho leaf-stalk flattened ont exactly liko a blade of grass, and bears pretty red flowers ; while L. aphnca has the stipules (or wings at tho base of the leaf-sta'k) expanded into a pair of large grccn leaves. Tho only shrubby pea-plants likely to be at present flowering are tho dwarf gorso (true furze has now poddcii), and the last stragglers of tho broom, both of which are too familiar to need description. Thus a einglo family has run away with all our space ; but it is better to learn this one well the present year, and take un another hereafter, than to overlmrdcn the mind with a lot of petty distinctions at once, few of which will be accu- rately remembered. Study tho plants of this single tribe, study th. ir leaves, thi'ir flowers, their pods, their seeds; compare them all carefully with one another, and yon will have done more good work in one month than if you learnt off, parrot-fashion, a hundred lists of half-known and half-understood species. THE HISTORY OF TUBERCLE. IN ptirining his investigations, Koch made nse of material derived from both human and animal sources. Kxamination of the tuljerculous material deposited in the lungs and other organs, in- variably led to the discovery of minute organisms possessing all tho bacterial characteristics of bacilli, and necessitated the conclusion that these forms of life are invariably present in such deposits. In yciipg tubercle, the bacilli were naturally more easily recog- nised ; but in older material, es)iocially in suoh as was dis- tinctly caseous, their presence could not always bo demonstrated, although abundant evidence of their oxistenco was found at the edges of such accumulations. In a multitude of cases of general miliary tubercalosis, bacilli in incalculiiblo niunbors were encountered in every affected situation ; and in effect it may bo taken as a warrautablo conclusion that they inevitably accom- pany the developmeut at least of tho disease. From this point, however, to a demonstration that they aro also tho cause of the degenerations which accompany their presence, is a considerable leap, the taking of whicli could bo justified only on tho accumulation of sufficient actual proof of the fact. It is the production of this proof that constitutes Koch's principal claim to tho gratitude of the BCiontifio world ; and tho manner in which it has bocn accomplished must win for its author an amount of praise such as fow rocont per- formances of a similar kind have merited. Naturallj', but one moans of supplying the needed demonstration presented itself — viz., tho adoption of exporinionts on living animals. For tho purpose, therefore, numbers of guinca-pig.s, rabbits, and cats were operated on, with the result, in every case, of verifying tho assumptions of tho experimenter. Uy directly transferring tho ^tuberculous matter from diseased animals to healthy ones, through inoculation, ho succeeded iu all cases in reproducing the disease ; but inasmuch as this proceeding was open to tho objection that tho transferred material might possibly contain a virus to which contamination was due, rather than to tho presenoo in it of microscopic organisms, it was modified liy tho introduction of "cultivation" experiments conducted on a very exhaustive scale. In this connection, perhaps, more than any other, must wo especially admire the unceasing persovoranco of Koch's pro- ceedings, and also unhesitatingly accept the results obtained from them. After lengthy trials, he succeeded in devising a jiabulum in which bacilli grew and reproduced with tho utmost freedom. At tho same time he was enabled to delcrmino the conditions which were favourable and essential to their development, thus arriving at the important discovery that they glow only within a narrow temperature range of 30° to 41° C. ; below the former, and above 42°, no increase took place even after the lapse of so long a period as three weeks ; thus a most important distinction is to bo drawn between the bacilli of tubercle and tho bacilli of anthiax, tho latter readily continuing the processes of active life down to a teinporaturo as low as 20° C. Preserving, then, his cultivation fluid at the appropriate tem- perature, Koch sowed a speck of tuberculous matter, and from tho generation of bacilli thus produced ho infected a second quantity of nutritive matter, and so on, until in some cases tho cultivation process was extended over as long as six months. The purified bacilli so obtained could not, by any possibility, be accused of com- municating any foreign virus ; and yet, when introduced into healthy animals, they never failed to reproduce themselves in incalculable numbers, and to set up all the symptoms of tuberculous infection. To quote ilcliiiite examples of tho experiments made in this direction, it may be mentioned that four gninea-pigs were inoculated with bacilli of tlio fifth generation produced in fifty- four days from tuberculous matter originally derived from a human being. In each case, the infected animal sickened and lost flesh, and being killed at tho end of thirty-two or thirty- five days, strongly pronounced tuberculosis was found in every instance. Tho situation chosen for the injection of infective material was fonnd to exert no influence on tho result. Tho abdo- men, tho anterior chamber of tho eye, and other places were selected, with always the same ultiniato consequences ensuing j and in cases where check experiments were tnado by injecting natural, healthy blood serum into animals at the same time as others were infected with cultivated bacilli, it was found that while tho latter sickened and became tuberculous, tho former romriinofl unaffected. In another series of experiments tho sputum of jihthisical patients was obtained and dried thoroughly for six or eight weeks. At tho end of this time, being suspended again in solution and injected into guinea-pigs, tho latter became rapidly emiiciati'd, and in every respect similarly diseased to those animals directly infected with bacilli obtained at once from tuberculous masses, or through successive cultivations. The iniportanoo of this particular observation will bo at onco apparent. It proves that hitherto unsuspected danger lurks in tho neighbourhood 6f every consumptive indivii^ual, and that ordinary piecautions are in- Buflicient to protect susceptible persons from tho influence of such producing agents of a dire and rapidly destructive disease. At the same time it must be assumed that it is ossontial for the infective bacilli to find their way into tho body under certain definite conditions in order for their development and the production of tubercnlous deposits to follow as a matter of course ; and it is on these by no means insignificant points that further information must be obtained by means of further experimentation. Were it June 16, 1882.] • KNOWLEDGE 43 oHiprwiso it would be difficult to explain the immnnity, such as it is, enjoyed from a disease so prevalent as tubercle, for it is estimated that one-seventh of the total mortality arises from it. And further than this, there is a stern necessity now shown to us to admit and attempt the discovery of a means of alleviating the disastrous conse- quences that follow on the general distribution of tuberculous disease. In this respect there must henceforth bo no unwise or careless compromise with sentimcntalism. Koch has contributed to our knowledge of the history of disease a discovery which bids fair to rank second in importance only to Jeni.er's ; and on the use wo maybe able to make of the facts already demonstrated must largely depend tlie influence it may exert on the destinies of the human taoo.— Medical I'ress. ON SOME CRITICS. IN a magazine like this, in which correspondence has been fre ely admitted, articles by those who have been invited to treat of a special subject because of their special study of it, are exposed to criticism, and, in some cases, to useful correction. We cannot always find room for letters conveying such criticisms, although the effect of the criticisms, sent as they are to the writer criticised, may bo fully felt in our pages. Some writers of letters complain of this as unfair, apparently imagining that these pages are intended to be an arena for controversies, and our chief editorial duty to be the regulation of such encounters. Then many of tlie criticisms which thus reach us are so worded that, even if our object were to make Knowledge a fighting field, the real unfairness would be in inserting them in full. For instance, instead of pointing out that some word or expression, used ]ierhaps by one of our ablest con- tributors, is open to misconception, a critic will calmly take it for granted that it was used under a misconception, and carefully explain (for instance) to Mr. Grant Allen some elementary botanical matter, or tell F.K.A.S. that a planet must be carefully distinguished from a fixed star, or Dr. Wilson that a whale does not, as he mis- takenly imagines, walk on four legs. Now, in such cases as these, it would not be foir, either to our contributors or to Knowledge, to insert letters in full ; or, in fact, to do other than send them to the writer criticised, so that whatever germ of useful suggestions they may contain may bear fruit. For my own part, a long experience in such matters lias made mo tolerably indifferent to criticisms of this sort, where I know that the paper criticised represents the result of honest work and thought, while the error corrected (or imagined) is in reality trifling. But writors of such criticisms must not bo surprised if at times a recognised authority on some subject is not particularly well pleased to receive a letter telling him gravely about the most ele- mentary matters in his own special branch of research. Still less must they be surprised, if, without expressing any annoyance, a writer thus absurdly criticised emjiloys a littlo sarcasm, more or less humorous, or tries whether his "friendly critic" likes a little of the same sort of criticism himself. I fancy, for instance, that in answering recently a criticism relating to his remarks on " Blood Corpuscles," Dr. Wilson by no means supposed his critic diil Dot know how to spoil the word "inaccuracy"; but, as that critic had explained that certain corpuscles are not round (that is, not globular), but circular. Dr. Wilson thought it as much to the point to explain to his critic that a certain word (misspelt, no doubt, through hurry, not of malice prepenec) should be spelt in a particular way. The critic writes very angrily to me, as the . harm in rnnkin^ a mistake, but great barm in makir •There i _ mistakes, and . hine."— TliVi.o. ' God's Orthodoxy is Truth."— Oar^* J! (Pur Coiffsipoiitifnrf Columns. METACIIROMATISM. [427] — There are a few mistakes in Colonel Ross's latest commu- nication to Ton (Knowlkuge, Juno 9, p. 25), which, since they involve aspersions on my character, I trust you will allow me to set right. These are the tmo facts of my intercourse with Colonel Ross. In April, 1874, I laid the JIS. of a projected research on inorganic colour-change before Professor Franklaiid, of the Royal College of Chemistry, Sonth Kensington. I commenced the experimental work of the research as soon as ever my duties would allow me, viz., in the first week of October, 1875. When my work was com- pleted fone day in December), the late Mr. Valentin brought Colonel (then Major) Ro.'fs, and introduced him to mo at my table in tlio laboratory. I was then given to understand thatMajor Ross's b<>ok on Pyrology was in the press, lie promised to send Mr. Valentin a co[iy, which that gentleman never received, as it after- wards transpired that either Major Ross or his agent sent the book to the Museum authorities, and they quietly deposited it on one of the librarj- shelves. I had no knowledge whatever of Colonel Ross's colour speculations, which, by the way, I now hohl, and can prove crporiracntally, to bo erroneous. Colonel Ross's statements on those matters have been denied before, many years ago, and I beg to refer your readers to a letter from Mr. Wra. A'alentin, in the Cherracal Newt of Sept. 22, 187C. But to return to the fortunes of my paper. There was certainly great delay in the printing of it. In the first place, it was not read until a month after being announced, because of my having to go on an expedition in connectionwith the Loan Exhibition of Scientific Apparatus, which was then being organised. It was read in Kcbmary. After months of delay I was requested to cut it down for reconsideration by the publication committee. This was done ; but for some reasons, best known to themselves, they decided the subject was not suitable for their jonmal. Hero Colonel Ross comes in with a glaring error, to call it by no worse a name. The article in the Chemical Xeira, towhieh ho refers as having influenced the Chemical Society's Committee, did not appear in print while they were considering the matter, but a while after, and it was from Colonel lioss's own pen. It is a communication he must have ofU'n regretted, m it stands there in the Chemical NewK for Sept. 8, 187C, a monument against him. When the Chemical Society refused my paper,! sent it at once to Mr. William Crookes, who very kindly had it printed at once. Wm. Ackboto, Fellow of the Inst, of Chemistry. [Wo hasten to insert Mr. Ackroyd's correction of Colonel Ross's statonicuts. It is evident there must liavo 1 nen Fome misappre- hension ou the part of the latter as In ilu' . uli i- in which events happened. Space is too limited to < i :ili!i u^ ;,. iii„l further rotm for matters rather personal than Fiiini ill. ; m il.at unless Coloi.el Ross is able to show that the dates nu i i i. i.i li 1 v Mr, Ackroyd r.ro inc-orroct, or to make other correction.'; EiiscrptiMe of definite veri- ficaiiim, our readers will not hear more about these matters. Rut we are sure they would gladly welcome Sir. Ackroyd's account of any exjieriments bearing on the scientific 1 lurcs," p. 223. Turning to fact, I asked a schoolnm i t r 1 i : i! II .iie, and out of 120 children in his school, 118 had brown Iniirof ii darker or lighter hue. 1 also asked a drill-instructor, and in a company of tG, above 80 had tlie same character. It is true that in some parts, chiefly in Cowal, in Argyllshire, there arc a very few black-haired Gaels. These, however, are not genuine Gaels, but descendants of the Fir-bolg, who were in Ireland before the Gaels, but being conquered, and having submitted, were incorijorated with the true Gaels. To distinguish them from these, they were named Tion-gall. From Ireland they passed to the Isle of Man and Cowal. Charles Stewaut. TUE FEVER TREE. [429] — Allow me to call 3-our attention to errors in the note on the " Fever Tree," pr.ge 608 [which was inserted by mistake — having been scored out from a column of other matter, but in pencil only. — Ed.] " The bark yields a febrifuge second only in efticienoy to quinine, but superior in all medical qualities to cinchona." Quinine is an alkaloid, cinchona the genuine namo of the various species of cinchona. There is an alkaloid called cinchonine, about the sixth part of the price of quinine, but as the only product of Eucalyptus at all know in this countJ-y is the essential oil, and the decoction of the loaves has proved a failure, I cannot understand the comparison. A febrifuge is said to reside in the bark, you will see, but I have not heard that it has been extracted. Whether the tree will grow in " the eastern and middle states" does not much interest us, but as it is extremely impatient of frost (perhaps I should say patient, for it dies off (piietly), I do not sup- pose it will. There were a fair number of trees in the south of England and Ireland that had gratified the hopes of the planters until the recent winters swept them all, I believe, away. I do not think it is acclimatised as yet in Italy, where a number have been planted in the Campagna; but I believe it has answered in Algeria better than in Euiopo. It is, of course, incorrect that the tree " produces no fruit or nut." W. SciiiTnALt, Pharmaceutical Chemist. SIDEREAL TIME. [430] — Amateur astronomers will thank "Ocean" for his com- munication of a " neat method " of ascertaining the approximate sidereal time at noon for any day in the year. Will yon permit mo to send his "neat method" reversed, by which any one may be enabled, without an ephemeris, to calculate from the sidereal time at noon any day in the year. For instance, to the constant 3'22 add the hours of sidereal time divided by 2, and also the minutes divided by 4. Taking his own example, we find that to the constant 322 Sidereal hours + !• Minutes + 013 5-5 Tlio result will bo the fifth day of the fifth month, or May 5. This "rovereod method" is useful for finding the day on which I JtsE 16, 1882. ♦ KNOWLEDGE <> 45 a given star, whose E. A. is knowii, will transit the meridian at any given time. For instance : — Keqnired to know en what dav Arcturus will cross the meridian at three o'clock. h. m Arcturus, E. A 1110 Spin. a Then to the constant 3 22 Add 17 h. divided by 2 8 0 70 m. „ 4 0 17 12 9 which is the 9th day of the 12th month, or Dec. 9tli. In the X. A. the sid. time at noon on Dec. 9th is 17h. 12n; Snetorrs to Coiitspontmits. the Editor req Office on or before the S'.tturJutf precedivg 1 inereating eireulaiion of which compelt u» to g HI5T3 TO COBBBSPO:fDByTS. — 1. A'o qhe>t can U anncered through the poet. 2. Leferi cannot he forvtirded ; eittion ihotdtd reach the of KSOWLEDSI, the ■ preee early in the week, t atleing for eeientijic information it to the Editor for corrttpondentt height. The difforenco, bow- over, would be verj- slight. It is due to the curvature of the earth : possibly in practice a further slight diffennce may be caused by the difference in tho atmospheric resistances.— O. It. Mvnne. 'Very likelv that is the way in which tho "cold snap" arises; but until it is explained, it can hartlly bo considered an explanation.- U. F. I am not awaro that tho late eclipse has taught us anything new in regard to metals in other worlds. Wo have not only known that there are metals in tho sun, but even that our fcmiliar metals exist iu stars so far away that their light takes years in reaching us.— E. S. STANt»N. What you saw was a range of lunar mountains, tho tops of which had jnst come into sunlight. — W. iloBOAN. You have certainly a.lopted the best of tho three courses which were open to jou. It wi.uld have pained mo very much to have hianl that a r.a.:.r had to stand on his head to read one of Ilho weather cl.nrts. and wo do not want Knowleii-.k turned upside down. The fact is that " "y^J'K to circumstances over which none of us had any control, the engraver was verv much hurried in preparing the weather charts; and in fixing th-. diagram for photograp' io -oiuct'on, he, unluckily, plnc.-d one upside down ; fortunately thoso diagrams were simf.ly 46 • KNOWLEDGE [June 16, 1882. fxporiinoiual. We have now Hxcd on a plan wo hope 1 Trithout any intorrnptioa for many years. ELECTRICAL ANSWERS. W. N. M. 1. I^jt a littlp loss bicliromato, say 2 oii. instead of tj oi. Tho crystallisation is probably duo to super-saturation ; 1 presume you made your solution in boiling water ? 2. Tho use of porous pots would inorcasc the internal resistance of tho coll, but this is f.ir more than compensated for by increasing tho constancy. A simple bichromate cell runs down in a few minutes, while one with a porous pot (especially if a little mercury, about 3 oz., is put in the pot containing the zinc) will give a continuous current for sovoral weeks — as long in fact as the constituents of the cell last. 3. Tho same current would bo obtained from two zincs and one carbon, as from two carbons and one zinc, but in tho former case there would be a larger, and therefore wasteful, consumption of sine. — George Pesdbill. "Resistance in feet per ohm" is on extremely awkward and clumsy expression. It is intended to mean the number of feet of wire which offer a resistance of one ohm. Thus, in the case cited, a wire of 0,826 feet to the pound, having a resistance in feet per ohm of 3 3, means that 33 feet (about ono mi^tre) of wire offer a resistance of one ohm. It is far better, more logical, and therefore scientific to ■peak of " Resistance in ohms per foot," or whatever length wo may choose as a standard. In telegraphy the standard length is one mile, so that we should say a mile of copper wire, No. 16 b.w.g. •ffere a resistance of 25 ohms. <0iir iHatDrmatical Column. THE LAWS OP PROBABILITY. A FEW cx.imp'es of the application of this rule to questions about hypotheses will serve to illustrate its real simplicity ; for, as is the case with nearly all rules, the verbiage necessary to remove ambiguity has introduced complexity. Ex. 1. — A teetntum has four faces, and it '« known that these are either numbered I, 2, 3, i, or 1, 1, 2, 2, or 1, 1, 1, 1 ; but the chances of these several arrangements are, respectively, as 3, 2, and 1; the teetotum is spun tince, and each time 1 is the number turned up. What is now the probability of the several arrangements ? If the first arrangement exists, the chance of the observed event is - X 7. o"" ,-^i 'f "'<' second is the actual arrangement, the chance of the observed event is - x -, or - ; and, lastly, if tlio third i.s the arrangement, the observed event is a certainty, or 1. Hence our formula informs ns that after the event, the chance that tho teetotum is marked 1, 2, 3, 4, is 1 1 1 3x_ + 2x- + lxl 16 -t the chance that the teetotum is marked 1, 1, 2, 2, is 2 x 1 over tho same denominator ; and the chance that the teetotum is marked 1, 1, 1, 1, is 1 y 1 over the same denominator. The denominator is That arrangement which wag antecedently the most likely Ih the moat unlikely of all after the observed event ; and the arrangement which was antecedently most unlikely is most likely of all after the observed event. It is important to notice how the antecedent probabilities, or the d priori probahilitlcR, as they are called, are modified after tlio observed event in such instances. For example, we may regard the spinning of the teetotum in this case as an observation or experiment, and the illustration shows ns how theories antece- dently more probable may become less likely as observation is ex- tended. The jnst appreciation of this fact is the essence of sound theorising, or, rather, of all science. I give next two examples tending to illustrate this point. Ex. 2.— .Suf^'»c the antecedent probability of the theory that the earth on vchich we live it at rest and the centre of planetary motions, to be a million times greater than the probability that the earth is a planet circling round the sun. Then on the former theo^-y, although a planet travelling round the earth might have a path so looped that tho planet would appear to follow looped paths in the heavens, yet tho chance of this occurriitg might fairly ba regarded as small. But set it at -, or an even chance. On the second theory, the jilancts would be certain to travel on looped paths, or the probability of their so doing would be represented by unity. .Yoie, there arc 120 plane's, all of which travel on loopid paths. Supposing no other facts known, what is the prohability that tho earth is at rest in the centre of the planetary system ? Here we liave two hypotlu I ho chances of which are respcc- lie chance of the observed event on the former hypothesis '•(^r our formula gives as tho probability tl centre of the planetary system— ioiioooo and on the latter i; earth ity. Uenco t rest at tho ^^ \2/ looeooi which reduces to ^"""^"-" -. 1000000 + 2 '•» Now, the logarithm of 2 is 0-3010300, and multiplying this expres- sion by 120, wo get 36'1236000; so that 2 "° is a number containing 37 digits, the first seven of which are 1328230 (because tho loga- rithm of 1-328230 is 01236001). Putting this value in tho abovo expression, and dividing numerator and denominator by lOUOOOO, we obtain for the probability that tho earth is tho centre of tho planetary system — l,32H,23O,000,OUO,00O,OUO,OOO,0OO,OOO,0UO I may bo permitted to select for my next example, a theory of my own. " Ex. 3. — Let it be regarded as antecedently a billion times more likely that the stars of our galaxy are spread with a certain general uniformity throughout the space around the sun, than that they are gathered into definite aggregations so marked in their character as to be recognisable in the stutistical distribution of tlie stars. On the latter hypothesis, it may be regarded as an even chance that on comparing the number of stars visible to the naked eye in the northern and southern hemispheres, we should find as great a diaparity as is represented by such a proportion as 7 to 5. But set the odds as 10 to 1 against such a result. Noiv it is observid that, as a matter of fact, out of 0,000 stars visible to the naked tye, 3,500 are in the southern hemisphere. Required the probabdity that stars are spread v:ith a certain general uniformity throughout space. In a paper which I communicated a few years ago to the Royal Astronomical Society, I showed that if the stars are spread in thia way, tho chance of tlio observed arrangement is (;tvJ«6769(T,ooo;odii,boo,ouo,u'uo f)n tho hypothesis that there aro definite stellar aggregations, tho chanco of the observed arrangement is n ^^^ But tho antecedent probability of tho former supposition is set by our question at 1.000,000,000,000 /p^ l,Oi)O,WU,0U0,(JOr that of the latter at only -- ^ (D) 1,000,000,000,001 Ilonco tho probability of tho fonner hypothesis in presence of tho observed fact is obtained by multiplying (A) by (C) for a, nume- rator, and adding that product to (C) x (U) for a denominator. It is (very approximately), 1 (A) nit,'.m>,(m),(m) reduces 00,906,090,011 "' 6,090,5.';3,636 that is, the odds aro more than six thousand millions to one against tho generally-accepted hypothe I do not think I have treated Juke 1G, 1882.] KNOAVLEDGE 47 this hypothesis! unfairly in setting the antecedent odds in its favour at only a billion to one. It would be easy to multiply examples of tlio application of the important general rule above stated; but what 8p.ic-e is still avail- able must be devoted to certain general considerations, to be care- fully borne in mind by those who discuss the probabilities of different hypotheses. {To ie continued.) A correspondent asks us how in Problem 33, p. 632, the point F can be determined so that the proposition — GA : AF : : HF : AH shall hold, GAand All only being known. This is so readily done that it had not seemed worth while to indicate the method. Thus, from U, the bisection of AH, di-aw MK pcrp. to AH, and equal to side of square equal to GA.AH. Join AK, and describe about A, as centre, tho circular arc MN. Then if HF be taken equal to MK, F is the point required. For if KA produced meet the circle NM in N', we have NN' = AH ; and, therefore, — HF.FA-NK.K\' = sq. on MK = GA.AH .-. GA : AF : : HF : AH ^r WiWt Column. By " Five of Clubs." WE now give the method of play for the illastrative hand in No. 30. The young Whist player will carefully note that tho lino on which Y and Z jilay in order to save and win the game is not that which should be followed if tho score wero love all, and honours not all with A B. For, tho position of the cards which causes T Z to save tho game by departing from rnle, and leading from weak suitS; is antecedently improbable. 1' Z play as they do, because it is their only chance. Had tho Knave of Trumps been cither with Y or Z, falling (irtt or second round to a higher honour, Y'b proper course would have been to play out his King and Ace of Clubs, then the Knave which ^'s Queen would have taken ; and whatever A led the game would be saved by Y Z. We note also that the play of tho hands is given here in accordance with Clay's suggestions; according to tho present sjstcm of discarding (to which Clay later gave in his adherence), Z instead of discarding a Club at round 3, would have discarded a Heart, thereby showing Y that Hearts wero his beet suit : — A. Spades— Q, Kn, 3,2. Hearts— 5, 3. Clubs— Q, 9, 8, 3. Diamonds — 9. Spades — A, K, C. Hearts— K, Kn, 2, i. Clubs— 5, 2. Diamonds — K, Kn, 3, The Ha B Y llonlpr. z Trump Card. Fioe qfSpaJ,,. A Score :— A, B,-=0. 1', /, = ■». r. Spades— S, 7. Hearts— 9, 7, 6. Clubs— A, K, Kn, 10. Diamonds— 10, 7, G, 5. Spades— 9, 5. Hearts— A, Q, 10, 8. Clubs— 7, G, l. Diamonds— A, Q, 8, i. Towd'b Rxtbaot is » certAin cnre for RhpumntiRm uid Qout. Pond's Kitrnct is a certain euro for nBemorrhaids. Pond's Kxtrsct is a i-prtain cure for Neuralgic pains. Pond's Kitnwt will heal Bams and Wonnds. Pond's Kitract will cure .Siirains and Druiscs. Bold by all Chemists, Get th« 0^0 0 0 * * 0 0 0 0 o o^o 0*0 0*0 * ♦ @ 0 o * + + 4. 4. 0 0 0 0 * t:.t *** 4. 4>^4> 4> 4> 4> TUB PLAY. REMARKS AND INFERENCES. Z 1. A, of courfe, leads Q of Trumps (see leads in former nnm- bers). y, B, and Z can all place Ku and ten in A'b hand, also two, three, and four of Spades from the play. 2. All the players should know where the remaining Trumps lie. 3. B not having noticed tho fall of Trumps, only counting tliem, leads Ace to draw another rouud, though r and Z have none, and ho ought to know it. The discards are as Clay gives them. Z's is mado on the old-fashioned piinciplc of discarding from shortest suits. 1' sees, however, that it is better for him to retain tho power of leading (as often as there may be occasion) to his partner. It was from such considerations that the modem principle of discarding from the longest suit when strength in trumps is declared against you, took its origin. 4. B leads from what he takej to bo r's weakest suit. Hearts and Diamonds being equally strung in his own hand. 5. If Y leads Clubs— in which suit his partner is weak — the game is obviously lost, for A has three more tricks in Trumps. If Z is not strong in Hearts tho game is lost ; therefore 1' plays as if he know Z to be strong in Hearts. Z finesses deeply. 6. r continues the Heart lead. 7. Z leads a Club, and I'Unessea the ten. 8. Y continnes the Hearts, forc- ing .4, who can only lead Clubs, in which suit i' is secure, and the game is won for 1* Z, I' n\aking three tricks in Clubs. PlAVI.VG to TUE CnANTKS.— " When I was a youngster 1 was looking over Clay, and late in tho hand he led Queen, from Queen, Knave, nine, and a small card. This was the old-fashioned lead, but a small catil is now led from Queen, Knave, nine, Ac, 1 after- wards asked Clay whether he con- sidered the old lead, as t;ivcn by Hoyle, prcforublo to the modem one. Ho said, ' No, I generally lead the small one ; bnt when 1 had the lead tho canls must lie lucky for us, or we lose tho odil trick.' By this ho meant that unless the King lay to his left, or tho ten to his right, and one of tho finesses succeeded, tho odd trick could not be won. I have won many an odd trick since by acting on a similar principle, and always think of Clnv when it comes off." —Cavendish's " Card-Table Talk." Norii'lM.— The First Volume of Knowlepok is now ready, bonnil in rod cloth, gilt lettered. Price 10s. G<1. Vol. I. cont.iina tho numbers from the commencement (Nov. 4, 1881 ) to No. 30 (May 26, 1882). A.s there is only a limited number of copies, tho Publishers adviso that orders should bo sent in without delay, to prevent dis- appointment. The Title-page and Index to Volnme I. is also ready, price 2d., post-free 2Jd. Binding Cases for Volume I., price Is. 6H. each. Complete copies bound (including Title, Index, and Case), for 2s. Gd. each. 48 KNOWLEDGE ^ur C&fsfs Column, By Mephisto. [June 1G, 1882. THE VIEXXA TOUiiXAMEXT. WE have received tliis fine game too Into for annotation. It was played in the twenty-fifth round on Saturday last, Juno iOth, between Herren Paulson and Winnwor. It was well contested throutrhout, hoth players voluntarily abandoning their Queens. By this victory Winawer has sustained a serious check, while Steinitz was thoreliy for the first time at the head of the list— viz., eighteen, while Winawer remained at seventeen. (»n Monday morning, according to telegraphic information received in London, Steinitz stood at 19 ; Mason, 18 ; Winawer, i7J ; Mackenzie, 161 ! Zukertort, IGJ ; mackburnc, 15i ; and £i.i:liseh, 15. WuiTK. Buck. I'dulwa Winawer, 1. P to K4 P to K4 2. Kt to KB3 K to QB3 3. P to Q I P takes P 4. Kt takes P Q to U5 5. Kt to Kt5 B to Kt5(ch) Whttb. n rminds, and then flrtt arid cij;,'htncnlh JtJfE 23, 1882.J ♦ KNOWLEDGE * MAG.4Z1NE OF S€1ENCE PLAINLY'^ RDED -£XACTl|pESCRIB£D _ | LONDON: FRIDAY, JUNE 23, 1882. Contents of No. 34. LtdiM" Dress So.ielT 49 Found Links. — Part VIU. Bv Dr. A. Wilson F.B.S.E., F.L.S. (lUuttrattdt m Thoaght-Readine By the Editor ... 51 Crystsls. Bv William Jago.F.C.S., [llluHrated) 52 English Seaside Health Resorts. Bv Alfred Hariland '.. 53 The Ejea of Science. By the ■ Amateurs. By A. On some PubUcations of the Chris- tian Knowledge Soi-ietv 5^ Reviews : " Story of a Museum "— "Curiosities of Vegetation" 57 Correspondence 59 Answers to Correspondents «1 Our Mathematical Column 62 Our Chess Column Kl Our Whist Column Ol LADIES' DRESS SOCIETY. EVERY one interested in the question of rational dress for women (and which of us — man, woman, or child — is not, directly or indirectly ?) should kno\s- of the Rational Dress Society, the objects of which are : — To promote the adoption, according to individual taste and convenience, of a style of dress based upon considera- tions of health, comfort, and beauty, and To deprecate constant changes of fashion which cannot be recommended on any of these grounds. The society seeks to promote its objects by means of drawing-room meetings, advertisements, circulating pam- phlets, leaflets, A-c, and also by issuing patterns which meet the approval of the committee. An annual sub.'^crip- tion of half-a-croNvn constitutes membership. Jlrs. E. ^M. King, 3-t, Comwall-road, Bayswater, is the honorary secretary of the society, and those interesteil in the objects of the society are requested to write to her. The president of the society is Viscountess Harberton, an important letter from whom appears in our corie.'^pondeiice columns. It is impossible to over-estimate the importance to all of us, of this question of rational dress for women (we use the more general and nobler word, for the movement is not intended to be limited to ladies). Men talk about it too frequently as if they were not personally concerned in the matter, yet there is not a man in civilised communities whose own individual health and constitution have not been aflected by the fashions of feminine attire. But if this were not the case, all men arc interested in the well- being of the women of their family, — mother, wife, sisters, daughters. If for unseltish reasons they are not (as they ought to be), there a^e multitudes of selfish reasons wliy they should be interested. What dress reform means to women, we leave women to show. As Jlrs. King well remarks in her little pamphlet on " Rational Dress " (published by Messr-. Kegan Paul it Co., price sixpence), it may be questioned " whether men are tjuite in a position to tilk alx)ut reforming the dress of women, still less to blame tliem for its follies ; for it is chiefly they themselves who have bound this burden upon women's shoulders," WTienever an attempt has been made at rational reform, the sneers and ridicule which have prevented women from accepting the reform ha\e come almost wholly from men. ''?^^: '^^^J They have not contented themselves, as they well might, by ridiculing extravagancies, they have ridiculed the essen- tial principles of rational reform. And it is to be observed that they adopt a manner in ridiculing reforms, quite dif- ferent from that which they employ in laughing at the follies of fashion. The laughter at the.sc amounts almost to encouragement ; the sneers at those are generally a.s coarse and otFensive as they are foolish. It is comforting to find that " women reformers have no such feeling of despair as that expressed by men," but, on the contrary, have perfect faith in the remedy they offer. " We know," says Ifrs. King hopefully, " that we are working on the natural lines, and upon true principles, and that these will of themselves achieve the moral, mental, and physical cure we need. We know that we are allied with the rising spirit of the age — that which manifests itself in the growing mental and physical activity of woman. We are ready to accept, appreciate, and profit by the greater generosity of [those] men who encourage and help us to obtain a like advantage with themselves in education : and to join them in their sports and healthy pleasures. "' FOUND LIXKS. Bv Dr. Andrew Wilson, F.RS.E., F.L.S. PART VIII. PASSING now to a very different group of animals^ we find the Tunicati'ii, Asciclian-i, or " Sea Stjuirts " (Fig. 1), to present us with certain highly interesting features for remark. These animals are usually regarded as poor relations of the shell fish or ifot- hi^cs ; and they exist both in a fixed and free state. The fixed "sea squirts" are tolerably common, and are found attached to shells and other objects dredgea squirt's " stomach (B) opens from the tlircat, and its intestine in turn opens into tlie atrium. A heart (/) exists in t]io shape of a curious tuK', which propels the l)lood for so many l>e«ts in ono direction, and then, reversing its action, sends that lluid for so many pulsations in the opposite direction. A single nervous moss lie.>! l>etween tlic two openings of the body, antl the other wall of the V>ody itself con- sists largely of a material called cfUuloif, which i.'» a Fig. 1. Amc,u,ox,,i»m, It Sen-.Squiit. (a, I'hnrj-iii, or ri'spi- mtoryportioiiof tlio l>ody ; B, stninach ; c, cgfr-prodiicing or- gan.) 50 • KNOWLEDGE <> [JusE 23, 1882. ,<>minon plant compound. Tlip animal in such a case nismifaeturos the sul)stance of the plant, and imitates the ohtluistry of the latter organism. ^uch is an outline of the rooted and fixed " sea squirt" Its'earlier history, however, is still more interesting. It ment exist, whether we like them or no ; and they alone are wise who can reflect, calmly and placidly and philosophically, that these facts in no wise detract from man's place in nature ; but, rightly viewed, only the more ennoble the humanity that, from such humble beginnings, has attained to the highest twig on the tree of life. Mr. Darwin's own words will bear quoting here: — "The most ancient pro- genitors in the kingdom of the Vertebrata at which we are able to obtain an obscure glance, apparently consisted of a group of marine animals, resembling the larvic of exist ing Ascidians. These animals probably gave rise to a group of fishes as lowly organised as the lancelet; and from these the Ganoids, and other fishes, like the Lepidosiren, must have been developed. From such fish, a very small advance would carry us on to the Amphibians." Mr. Darwin's words are again worth quoting, when, in speaking of the origin of man, he remarks that "it is only our natural prejudice, and that arrogance which made our forefathers declare that they were descended from demi-gods, which leads us to demur to this conclusion (that of man's descent from lower forms). But the time will before long come, when it will be thought wonderful that naturalists, who were well ac- quainted with the comparative structure and development of man, and other mammals, should have believed that each was the work of a separate act of creation." And, finally, concerning the often-assumed degradation of vcM-tebrato ancestry, the late distinguished author of the " Origin of Species " has a noble passage wherein he gives the death- blow to all arrogance of heart and mind respecting the origin of the highest forms : — "Thus we have given to man a pedigree of jjrodigious length, but not, it may be said, of noble quality. The world, it has often been remarked, appears ss if it had long been preparing for the advent of man ; and this, in one sense, is strictly true, for he owes his birth to a long line of progenitors. If any single link in this chain had never existed, man would not have been exactly what he now is. Unless wo wilfully close our eyes, we may, with our present knowledge, ap- proximately recognise our parentage ; nor need we feel ashamed of it The most humble organism is something higher than the inorganic dust under our feet ; and no on<: with an unliiassed mind can study any living creature, however humble, without being struck with enthusiasm at its marvellous structure and properties." In a concluding paper I shall deal with the evidence for " Found Links," furnished by a study of fossil and extinct maiiiMials and quadrupeds. SrECfLATlON in oloctrical companies' sharoa is becoming very ilnnKcrons for the uninitiutod. Our Bpiritcd contemporary, the Eli'clrical Rerip.w, Revorely comments on one of those companies, namely, tho " Self-Generating Electric Light and Power Company, Limited." A ropreeentative of tho journnl called at the office for information, and was shown a Bnnsen coll and a .Swan lamp. These constituted the stock. Ho was informed that Mr. Simon (tho inventor of the company's embryo spcciiility) had not yet com- pleted his lamp. Mr. Simon ir, ncvertheloss, to rocoivo out of a nominal capital of £300,0(X), tho sum of £120,000. This speaks volumes. Amongst tho works modestly contemplated by tho company is " To manufiicturo bricks, quarry stono, manufacture coraont and concrete, and to construct tunnels or subways for carrying wires or conductors of olectricity, and to construct railways, tramways, or waterways." It is also contemplated to carry on, or at any time to ceaso to carry on (!!!) tho business of mannfactnrors of oloctrical generators or accumulators, lamps of all kinds, Ac. It is to bo feared that we shall hoar a deal of anch companies before tho year is out. June 23, KNO^A^LEDGE 51 THOUGHT-READING. By the Editok. •\T7E have received from several correspondents cora- VV munications on the subject of Thought-Roadmg and the Willing Game as now practised in parlours and drawing-rooms. Several very remarkable narratives have been sent to us, which we have been invited to publish, along with the various theories suggested by the narrators, these theories usually resolving themselves into a vague impression that the observed results are due either to electricity or to animal magnetism. Now, there can be no question that among the phenomena observed during these experiments there are many which are well worth scientific investigation. Even in cases where there is wilful trickery, a degree of sensibility is manifested by some among the "subjects" which is far greater than had been previously imagined, at least by those unacquainted with such remarkable instances as Dr Carpenter and others have described in treatises on mental physiologv. Take, for instance, such a case as the following, described' by Prof. Barrett in the current number of the Ninofeenth Century :— " A young lady could write words, or even rudely copy sketches which had been shown to her mother and not to he rself , the mother sitting behind her and placing a finger on the girl's bare arm, even above the flexed elbow." In this case careful experiments proved that indis- cernible and probablv unconscious movements of the touch- ing finger served to convey a sufficient guidance to the girl's delicate skin and quick intelligence. But no one who has examined such cases as this, and recognised the wide range of difiference between one person and another m sensibility to slight muscular impressions, can attach any weight to the custoraarj- protestations in drawing-room experiments. On the one hand, the person guiding asserts that there has been no guiding, and probably often believes that there has been none ; on the other, the person guided is as ready to asseverate that there has been no guiding influence whatever (and possibly may have recognised none). But experiment shows that there has been. Thus, we must not be expected to find space for accounts of remarkable cases of apparent mind reading or mind- guiding,— generally sent without any of the details that have scientific ^■alue, and without any attestation more satisfactory than some remark that the writer hnovs there was no trickery. Nor can we admit, as a scientific expla- nation, the expression of a belief that there must have been magnetism. As Professor Barrett remarks, the ex- planation " It is magnetism," seems perfectly suflicient " to many who, for a thousand pounds, could not write down a single true sentence on the ascertained laws of magnetic attraction;" while, "if one ventures euphemistically to suggest this, they usually take refuge in 'animal mag- netism,' a phrase so obviously ordained by Providence as a safe retreat, that it would be brutal to drive them to bay on it." But there is room for scientific research into this matter. Some of the experiments already made under suitable test conditions have led to results so remarkable, as to show that the subj ct is well worth examining closely. Professor Barrett, Mr. Edmund Gurney, and Mr. Frederic W. H. Myers have been at some pains to collect evidence which is, indeed, as yet incomplete, but still seems to indicate a real power of mind on mind which, to say the least, has not yet been explained. They attach somewhat more weight, relatively, to the mind-reading side of tlie ques- tion than I am disposed to do. It seems to me the real point to be attended to is the power of mind in guiding mind, not the aptitude of some minds to be guided— though, of course, both are parts of the same subject of inquiry. There are cases in which mind-guiding seems the prominent feature ; others, in which mind-reading seems chiefly in question ; others, in whicli it is doubtful whether one or the other has been principally at work. Take, for instance, the following case described by Dickens in a letter to Forster. Dickens is here speaking of a professional conjurer, and therefore trickery may have, or rather must have, the fullest possible influence assigned to it ; Vjut trickery will not explain the mental phenomena. Dickens speaks of the man as " a perfectly original genius, putting any sort of knowledge of legerdemain such as I supposed that I possessed at utter defiance" : — " You are to observe," says Dickens, " that he was loith the company, not in the least removed from them, and that we occupied the front row. He brought in some writing-paper with him as he entered, and a black-lead pencil ; and he wrote some words on half-sheets of paper. One of the.<;o half-sheets he folded into two, and gave to Catherine [Mrs. Dickens] to hold. 'MadauK-,' he says aloud, 'will you think of any class of objects'!' 'I have done so.' 'Of what class, madam'?' 'Animals.' 'Will you think of a particular animal, madam V ' I have done so.' ' Of what animair 'The lion.' ' Will you think of another class of objects, madam r 'I have done so.' ' Of what class r 'Flowers.' ' The particular flower 1' 'The rose.' ' Will you open the paper you hold in your hand 1' She opened it, and there was neatly and plainly written in pencil : The Lioiu The Rose. Nothing whatever had led up to these words, and they were the most distant con- ceivable from Catherine's thoughts when she entered the room." Unless we suppose that by some amazing feat of leger- demain the conjuror, after Mrs. Dickens had named the rose and the lion, substituted for the paper in her hand one on which he had written those two words, doing this in the momentary interval between her naming the rose, and opening the paper in her hand, we must suppose that he influenced her mind in some way (the determination of which is what science yet has to seek) to think first of a lion, then of a rose. The interpretation of the trick as a feat of lefjcrdemain is, of course, quite out of the question. There were thousands of objects of which ^Irs. Dickens mi"ht have thought first, thousands of which she might have thought next : therefore millions of combinations of two objecte of which she might have thought. The con- juror could not possibly, then, have had ready to hand, anion" a multitude of papers, one containing in right order the two Mrs. Dickens had selected. He could not possibly have written those two names on a piece of paper in the moment between her answering " the Rose " and opening the paper in her hand at his request. Still less could he have combined (in this momentary interval of time) the .iccoiu- plishment of this foat, with the extraction of one paper from her hand and the substitution of another, without any knowledge of the change either on her part or on that of the audience, including such a keen observer as her 1ms- band It seems certain then that the conjuror guided her mind by will power to think of the objects whose name* he had already written on the paper. (To he fonlinued.) Tkrbific TiiUNDKR-sTOBSi AT TlKRLiN.— A terrific- thnndemtorm visito.l nerlin on Monday, tho 2911. ..It. Fro,n ''^'fl'"-^' '7° "»""';■. ,m..t three tho firo bripndc wore su.nmono. .m fewor 'h"" ''^"''J oiKht times to oxtinRuish fires catiscl by ''«''«'"";?• '"^''.^'"rr;! no serious confl^prations. The storm was confinod to Borlin and .ta immediate ncighbonrhood. ♦ KNOWLEDGE • [June 23, 1882. CRYSTALS. By William Jaoo, F.C.S., Assoc. Lsst. Cuem. ANOTHER group of rocks is tliat in wliiih tlie structure is wholly crystalline; they contain no glassy base, and often the crystals are sulliciently large to be readily ilisccrneil by the naked eye. From the very fact that the crystals are so packed and "crowded, it often follows that their shape is not perfect ; those last formed must of necessity tit them- selves into the spaces left for them. Fig. 1 is a micro- scopic study of a i-ock of this description. This particular specimen at one time formed a part of Cleopatra's Xeedle, and thus possesses some littli' interest additional to that it derives from its geological cliaracter. This rock, usually termed " Syenite," is essentially composed of the minerals felspar and hornblende : the specimen before us also con- •liiis (juartz. KiK. Hornblende is a mineral of a very dark colour ; and even in thin sections is almost opariue ; but little of it is shown in the figure. There is, however, a small piece in the upper part of the field, represented by very dark cross shading. To the left is seen a space which, save a few Btraight lines, is almost free from markings ; this portion of the rock is quartz. Starting from the Ijottora of the figure, and occupying the whole of tlie centre, is a portion of a crj'stal of felspar, approximately square in section. The felspar of Cleopatra's Needle is of special interest to the geologist from some peculiar markings it shows when viewed by polarised light. These consist of a series of striations, across the crystal (from left to riglit of the figure), but as they are most brilliantly coloured, it is impossible to represent them in a plain black-and-white sketch. To us, who are at present engaged in the study of crj-stal life and growth, there is one lesson in par- ticular the felsfjar crystal teaches us. It may be noticed that the crystal is cloudy, instead of being clear like the quartz ; this cloudiness has developed very fully in the upfx;r right-hand comer of the crystal, where, in the figure, it is repre,8ent^;d by a sort of stippling effect, but the whole crjstal is permeated by it, although to a lesser extent From a comparison of ditFerent rocks it is found that the felspar of some are almost clear, while in others the mineral is entirely changed. Those which have been most subjected to the action of " weather- ing," have suft'ered most. Rain, frost, and last, but not least, the atmosphere, gradually do their work, and slowly but surely demolish the crystal edifice, so laboriously built up by Nature in her constructive moods. Felspars are par- ticularly liable to decomposition ; the lime and potash or soda they contain are dissolved out by water containing carbon dioxide in solution, and leave behind a form of sili- cate of alumina, to which the name of kaolin has been given. This substance will be more familiar to many as " china clay." It is to this kaolin that the cloudy nature, of the felspar crystals is due, and in but few rocks is the felspar entirely free from it Not only, then, have we crystal growth and life, but these are followed by crystal decay, and ultimate decomposition. Water, the grand agent of geological denudation, not only does its work in the form of the beating wave and the rushing torrent, but also acts quietly on a gigantic scale on the constituent molecules of rock matter, and reduces them to the line mud and sediment fiom which are again built up our vast form itions of sidnncntary rocks. It IS \\ell known that sedimentary rocks, after a time, b((Oiiie much altered in appearance and properties. This IS ji iititui lily noticeable in those strata which, lying deej* li(ii(ath tli( surfue, arc subjected to enormous pressure iiul a tonsideiable degree of heat. Although the rock iiiu not be melted, still the heat favours in a remarkable 111 iiiiii 1 the ti ndeiK J of the particles to assume once more;- tile ei)stilline foim Fi;,'. -'. Fig. 3. Fig. 2 represents a piece of slate from Bavaria, which has been altered l)y the intrusion of some eruptive rocks. Under the heat produced, crystallisation has set in, and the slate contains a ejuantity eif crystals of a mineral known as chiastolite>. The section of one, almost at right-angles, is figured. This particular .specimen tells us much of the growth of the crystal. We notice that it has suce:(^e'eled in thru.sting the grain of the slate aside where it me;t it per- pendicularly, but where the growth has been in the; line of cleavage of the slate, the slate has held its own ; two oppo- site corners of the crystal are thus imperfect Fig. 3 is a ske;tch of rock called " granulite." It is a highly-meta- morphosed, sedimentary rock ; the whole mass is crystalline, the crystals being arranged, however, in re-gular lines, thus furnishing a clue to its origin. The two larger masses drawn are imperfect crystals of garnet — a plentiful mineral' in rocks of this type. The rocks have afforded us some striking examples of crystals — tlieir growth and decay. One last lesson they JcNE 23, 1882.J ♦ KNOWLEDGE ♦ 53 may teach us : Nature's methods are always those of law and order, nothing is done at random. In greater matt-irs this is self-evident, and in subjecting her work to the closest scrutiny we ever find her faithful to herself. ENGLISH SEASIDE HEALTH-RESORTS. By Alfred Haviland, M.R.C.S., F.R.M.C.S. Lond. CLASSIFICATION (Continued from page 40). The Daily Range of Temperature Accordiko to Latitude. THERE is no more important element in climate than the range of temperature ; it is the element by which we distinguish continental from insular climates ; and the facts relating to this range enable us to deduce laws, so well formulated by Haughton,* viz : — 1. In thf, northern /lemisphere, places which eiijoy a maxi- mum mean annual temperature have also a minimum range GJ annual temperature ; i.e., they have an Insular climate. 2. In the northern hemisphere, places which possess a mini- mum mean annual temperature have also a maximum range of annual temperature ; i.e., they have a Continental climate. 3. Large masses of land, anywhere, increase the range of annual temperature; and Inrye masset of water, anywhere, diminish the range of annual temperature. Now, although the climate of England is eminently Insular, yet for our present purpose we may, for the sake of comparison, divide it into inland and coastal : the former representing the Continental, and the latter the Insular division of the English climate as a whole. The sea-coast is not resorted to altogether for the sake of the pure sea air, that those who reside in inland towns so enjoy during their outings and search after health. There is yet another reason, unfortunately felt by many in weak health, and that is the necessity of avoiding the extremes of heat and cold, and the greater range of temperature, which are ex- perienced in the inland climate. In summer, the sea moderates the heat of the coast line, and in winter tempers its cold ; the more perfectly, therefore, these conditions obtain, the more perfectly will the climate of the health- resort fulfil the requirements of those who are anxious to benefit by its influences. This can easily be illustrated by referring to the records of the daily range of temperature at the following inland and coast stations for 1881 :— At Salisbury, by Thomas Challis, Esq., of Wilton House ; at Stockton, near Rugby, by the Rev. W. Tuckwell ; at Gloucester County Lunatic Asylum, by E. Toller, Esq., M.R.C.S., F.M.S.;at Brighton, by E. F. Sawyer, Esq., F.M.S. ; at Llandudno, by James Nicol, Esq., M.D. ; at Scarborough, in Dr. John W.Taylor's ^M.O.n.) Annual Report for 18S1 ; at Liverpool, by John Hartnup, Esq., F.R.A.S. ; at North Shields, by Robert Spence, Esq. ; and at Lowestoft, by S. H. Miller, Esq., F.R.A.S., F.M.S. During the first quarter of 1881, the i/rsnYesi range of temperature was observed at Salisbury, 15° 5; Stockton, ll°-9 ; Gloucester, H°~t—mea.n, l.')°0. The least at Scar- borough, 7°-4 ; Llandudno, 8°-6 ; North Shields, 8°-7 ; mean, 8°-2 ; difference, 6°'8. During the second quarter, the greatest range was at Salisbury, 2G°-3 ; Stockton, 22°4 ; Gloucester, 22°-5; nwan, 23°-7. The least at Scarborough, 11° 8; Llandudno, 12°1 ; Lowestoft, 12°-3; mean, 12° 0; difference, 11°". • " Six Ijoclnrcd on Physical Geograpliy," by tho Uev. Suniuul Haughton, M.D., F.B.S. Dublin University Press Scries. During the third quarter, the greatest was recorded at Salisbury, 22^-8 ; Stockton, 21°-3; mean, 22°-0. The hast at Llandudno, 9°-7 ; Liverpool, 10'-4 ; Scar- borough, ll°-8; mean, 10°'6 ; difference, ll°-4. During the fourth quarter, the greatest range was at Salisbury, 17°-7; Stockton, 14°-0; mean, 1.5'' 8. The least at Scarborough, 7° 9 ; Llandudno, 9° 3 ; at Brighton, 9°1 ; mean, 8=7; difference, 7^-1. If we com- pare the above figures with the mean daily range of tem- perature throughout England for the four years 1878- 1881 inclusive, we shall see at a glance how natural a division there is between the coastal and inland climates. All En^>lmid-1878-18ai. „,^,.., i,.., ' Mfsn Mean Daily Daily Hanse. Inland-!881. Daily Bangf. Coaatal-IMl. '»«• First Quarter SS"? ... ll°-3 ... 15'0 . . S'^ ... 6°-8 Second „ 53°1 ... KT-S .. 23'- . . 12'0 ... ll'-7 Third „ 58P-3 ... IS"-* , .. 22''0 . . 10'-6 ... ir-4 Fourth „ 42°-5 ... ll'-7 .. 15°-8 . . H'^■^ ... 7"1 Annual Means 48'1 ... 13°-6 ... 19' 1 ... 0"-8 ... 9°-3 Again, referring to the first law of climate above as to the highest mean annual temperatui-es being associated with the least range of temperature, we have the following figures to show how this is exemplified in England, when the inland and coast climates are compared according to latitudinal position. The temperatures belonging to the interlatitudinal space, .50° to ST N., were all recorded at coast stations, and we have selected Ventnor as the repre- sentative of this space, simply from its central position and its separation from the mainland of England. All England, 1831. Diffract. Mean Diffnicf. Parallels of Latitude. North. Mean Mean Coastal T^rT •" ""V "> „ ., Kepn-senla- 'f^^P, favour RanRO favour Temp. Daily ,1,.;;^ ,gg, of the ^f „, „, ,^g HanRe of • Air. Coast. Temp. CoMt. Bl-sa 481 .12-53 46 9 63-54 4«4 54-55 13-4 its- "I'S- *»(!• *'?• Ventnor 49-2 +01 11 4 -»1 Barnstaple ... 60 6 +24 13J -»S Lowestoft ... 47-6 +07 ll'S -SS Llandudno ... 486 +22 liVl -S-» ScarliorouRh.. 471 +17 9 5 -40 Thus we see that the coastal representatives have both a maximum mean annual temperature and a minimum mean daily range of temperature in accordance with the above proposition. We see also that the greatest daily range of temperature takes place, both inland and on the coast, during the second quarter of tlie year (or during April, May, and June). We find the sea, as it were, postponing the effects of summer and autumn, and giving out its store of heat during the last months of the year, the mean temperature of which is 42° 5, compared with 38°-7 during the first quarter. On the other hand, it absorbs in spring and early summer a more than fair proportion of the solar heat Hence it is that many seaside health - resorts afford a warmer climate up to January, and even February, than inland places, and many persons, on this account, go to them from large towns to enjoy their prolonged warmth and equability of temperature. On the other hand, aftvr the winter has destroyed the last lingt^ring trace of tie previous summer heat, and chilled tho s.\a and the land, then it is tliat invalids feel the want of .shelter fivm cold winds during March, April, and May, and those resorts become the most frequented which afford the gn^ntest protection from these winds during tliis most critical period of the year, when more fatal chills are contracted than at any other time- more latent seeds of consumption excited into activity and development than during tho cold of winter. Hence it is that we find on all the more exposed parts of the coast of England a liigh mortality from this disease ; but this subj.^ct must not be anticipated, as it will be dealt with in its proixr place. 54 • KNOWLEDGE [Junk 23, 1882. THE EYES OF SCIENCE. Bv THE Editor. THE U'lcscopo, tlie microscope, and tho spectroscope give to the student of science what may be re- garded as three kinds of visual power — in one case unlike the visual qualities possessed by the natural eye, in the other two surpassing these greatly in degree. We can conceive creatures endowed with the powers of vision which the telescope and the microscope artificially supply. Indeed it is by no means incredible that in other worlds than ours creatures may e.xist possess- ing powers akin to these. And although it is not easy to conceive the sense of vision so increased and extended that by means of it the analysis of liglit effected artificially by tlie spectroscope could be eQcctcd naturally, yet there is nothing absolutely outside the range of possibilit}-, even in this. The eye is, indeed, an optical instrument, precisely as the ear is an acoustical instrument ; and so far as wc can judge, the sense of vision might have been provided with a more complex organ, or series of organs, giving it greater range, as in the telescope, or more complete power of magni- fying minute details, as in the microscope, or the power of separating light-rays of diUerent refractive nature, as in the spectroscope. There are other optical instruments also ■whose powers might have had tlieir analogues in the organ of sight (as the i olariscope and similar instruments) ; while there are others, as the stereoscope and so forth, which, like the telescope and microscope, are akin to the organ of vision, but give to it increased power in particular way.s. I have lately been led to notice how certain photographic processes and methods extend tlie powers of human vision, and enable us to see what, owing to certain peculiarities in the circumstances under which eyesight is employed, we are debarred from seeing in the ordinary way. It has long been noticed that photographic vision, so to describe this method of studying natural objects, has one great advantage over ordinary vision in that it is not liable to ordinary misleading influences. In science, seeing is not always, or even generally, believing — for the simple reason that the student of science cannot always be certain what he really sees. Thus an observer may be misled by imagination, es- pecially if some favourite theory has possession of his mind. If he knows, or thinks he knows, what he ought to see, or might fairly expect to see, he is very apt to imagine that he actually does see it In this way, for instance, many students of astronomy liave fancied they have seen a small companion by a star in a position where they had been told such a companion existed, when, in reality, there had been some error in the description, or in their reading of it, and either no such companion existed, or else it was in some entirely different position, and perhaps quite beyond tlie range of the telescope employed by the observer. Again, the eye is repeatedly deceived by effects of con- tra.st. Thus, the French astronomer Chacornac advanced a Tery ingenious— indeed, masterly— theory in explanation of the circum.stance that the disc of the planet Jupiter is brighter near tlie edge than in the niiddh;, tho only objec- tion to his theory rcsidiug in the circumstance that the disc is darker, not bright/r, near the edge, though to the eye it appears brighter there by contrast with tho dark back- ground of the sky on which it is 8ecn proj(;cted. 8o again there is a charming theory, in vogue tfj this day among many students of the n.oon, explaining why the floor of the lunar crater I'lato (the Greater Black Lake of the «rlier t<;lescopists) grows darker as the sun pours more light U{Kjn it (rising higher in the sky as supposed to be viewed from Plato), the real fact lx,iiig that there is no such darkening, the apparent dilforence being entirely due to eiiVcts of contrast — the contrast of the floor with the black shadows of the crater-ring thrown upon it wlicn the sun is low, and the contrast of the floor with the brilliant white of the surrounding crater-ring when the sun is high, one contrast making the floor look lighter than it is, wliile the other makes it look darker. I may cite another instance of an optical illusion, caused by on etiect of contrast— a case not requiring telescopic obser- vation for its recognition. If on a moonlit night one looks beyond a water horizon towards the part of tho sky below the moon, that region looks darker than the parts of the sky on either side ; yet, in reality, it is no darker — if anything slightly lighter. What causes it to look darker is the apparent* brightness of the part of the water just below the moon, where lies seemingly* a broad track of silver light. If this track of light is concealed in any way, as by holding up a sheet of card or paper, the portion of the sky immediately above is at once seen to be at least as bright as the parts of the sky on either side of it. So in multitudes of other cases — some familiar, some otherwise — the eye is deluded by effects of contrast. Photography, or what may be called photographic vision, is not, it is true, altogether free from defects, corresponding to such defects of vision (resulting in illu- sion) as we have just considered. As tliere are physio- logical illusions in ordinary vision in such cases, so are there in certain applications of photography, physical effects which may prove similarly illusive. For instance, there is what is sometimes called photographic irradia- tion, when around a dark object in a photograph a ring o£ light is seen, or around a bright object a ring of darkness, this ring not corresponding to any really existent object, but resulting from some change in the photographic film along the border-line around a region acted on very strongly by light. Again, the photographic eye has long been justly valiuid for its artistic power, in being able to record, without defect or exaggeration, what it sees. If we take, for instance, one of Dr. llutherfurd's photographs of the solar disc, and compare the spots there depicted with those shown even in the most carefully-executed pictures of the sun before and since, we see at once how liable the eye is either to be deceived in what it sees, or else to fail duly to guide the hand in reproducing what the eye has seen. I happen to know of a case where a draughtsman took ex- ceptional pains to reproduce, without exaggeration, the aspect of the solar disc with its spots, when yet, on com- parison being made with a photograph taken nearly at the same time (though 3,000 miles away), it appeared that the spots had been notably exaggerated. I refer to tho draw- ing of the sun's face which forms the frontispiece of my treatise on The Sun. I was particularly struck by the aspect of the sun when that drawing was made, and I certainly spared no pains to delineate tho spots correctly ; but a comparison of my picture with a well-known photo- graph by Kuthurfurd, which chanced to be taken aliout the same time in New York, will show that though the spots are delineateil, individually, correctly enough, they are consiy immersion in a saturated solution of hyposulphite of soda (or thiosulphnte of soda, to use the correct name). This method of development has the advantage of being clean and very easy to manage, but it has the disadvantage that the solution is not constant, and the results are not always to be relied on. Of course, it is possible to become so familiar with a process that difficulties in the hands of one operator are not met with by another. Development with pyrogallic acid is the method in most general use. Jlr. Kennett's formula is : — Solution No. 1, pyrogallic acid 4 grains, water 1 oz. Solution L', ammonia (sp. gr. -t^SO) half an oz., water 8 oz. Solution .'?, potassium bromide 3 drs,, water 8 cz. Solutions 2 and 3 may be kept mixed together. It is not necessary to weigh the pyrogallic acid for every plate. Keep a small bone spoon for the purpose, and after once weighing the proper quantity, notice wliat is required for the si/e of jilate, and with the spoon sufficient may be yitessnf, a small quantity more or less being of very little consequence. But if Mr. Kennett's method bo followed, lake of No. 1 one ounce, and add to it one dram (or drachm) of tlie amuionia and bromide solution, which must be poured over the plate while lying flat in the tray. If any air-bubbles appear on the plate, they must be carefully removed, and the KNOWLEDGE • [June 23, 1882. solution must be kept in constant motion, not violently, or airbubbles will be caused. In a short time the picture will appear, but the development must be continued until a strong image is seen when the plate is examined by trans- mitted light Experience witli a wet plate is of little use here, as the appearance of the image is quite diflTcrent. The development miist be continued until there is an appearance of gi-eat density, and the back of the plate Wing examined, the picture should to some extent be visible there. Practice with a few plates will be worth more than pages of written description. Any make of gelatine plates may be developed with either of the solutions named, but in some cases it is atlvisable to follow the directions to be found with each packet of plates. If the picture do not appear in moderate time, the ex- posure may have been insufficient, and more of the bromide and ammonia solution may V)e added. If the picture appear too quickly, it sliows that the exposure has not been cor- rectly timed. It is as well to add too little of the bromide solution, as it is easy to add more if the picture be tardy in developing. Under-exposure is apt to produce hard nega- tives and over-exposure too little density. Too much attention cannot be given to the washing of gelatine plates. Running water may be used — a gentle stream is sufficient—or the plate may be placed face down- wards (not touching the bottom of the dish) so that the thiosulphate of soda may be washed out, the water being clianged several times. .Should the negative appear to be too thin, it may be intensified as follows : While wet, flow over the plate a saturated solution of bichloride of mercury. Notice the effect, and take care not to over-intensify. At the proper moment return to stock - bottle and wash the plate thoroughly ; then flow over it a solution of ammonia, one ounce to eight ounces of water. This will darken the image, and the plate must be again thoroughly washed. The mercury and ammonia solutions need not be thrown away, as they can be used till exhausted. If the mercury (or intensifying) solution be found to act too vigorously, it n»ay, of course, be weakened by the addition of water. Simply flowing the solution once over the plate is often sufficient, while in otlier cases the action of the bichloride may be allowed to continue until the picture is bleached white. While wet, a ge'atine plate must not be dried by a fire, as a collodion plate may be. It has been suggested that if surface-dried with blotting-paper, the plate may be dried by fire-heat. If carefully done, this method is effectual. When dry, the negative may be varnished in the usual way ; or if only a few prints are required, the negative may be printed from without varnishing, care iK-ing taken not to use the paper damp. OX SOME PUBLICATIONS OF THE CHRISTIAN KNOWLEDGE SOCIETY. '■pHE Society for Promoting Christian Knowledge has X now for many years l>een remarkable for the singu- larly able manner in which its Committee of <^leneral Literature and Education have conducted the puVjiLshing arrangements of the .Society. No .sectarian influences are allowed to interfere with the quality and character of the )x»oks published : in every case the question which the committee w^ems always to have had in view is whether a subject will l>e tr.-ated ably, honestly, and thoroughly. The Maxu.\ls of Elementahv Science, for example, have been prepared, without exception, by writers thoroughly conversant with their various suV)jects. From Professor Fleeming Jenkin we have an admirable treatise on Electricity, clearly and brightly written — and we need hardly say, soundly. Mr. I.e Gros Clark has written an excellent treatise on Physiology : one of the very best extant, for its size. Those who take interest in Crystallography will find the manual by Mr. H. P. Ourney full of useful matter, verging strongly towards the mathe- matical ; but the nature of the subject rendered this almost unavoidable. The treatise on Matter and Motion, by the late Professor J. Clerk Maxwell, is open to more serious exception in this respect, having unquestionably gone beyond the line which separates the profound from the popular. Professor Clerk Maxwell was never able to appreciate the difficulties which beginners find in dynami- cal and kineiiiatical matters ; but in this little book he seems to have thought that the best way to avoid them was to pass boldly into the region where vectors freely roam, and the result is mystery and misery to beginners. It docs not content them to learn that, "as indicating an operation, AB is called a Vector," and that " the opera- tion is completely defined by the direction and distance of the transference " ; nor is it any satisfaction to the incjuiring mind to know that " the starting-point, which is called the Origin of the Vector, may be anywhere." Yet this is all which Professor Clerk Maxwell tells them about vectors in defining these useful articles. The S.P.C.K. should have a manual prepared, to which Professor Maxwell's might serve as a sort of sequel ; for, unquestionably, a student of matter and motion is much aided, later in his studios, by the vectorial method. At present, however, it must be admitted that the manual by Professor Maxwell is an exception (and a solitary one) to the generally useful character of these science manuals. Mr. Bernays' manual on Chemistry and Mr. Newton's on Zoology are excellent Of Mr. Proctor's manual on the Spectroscope we must not say more than that the author has honestly endeavoured to bring the work up, in clearness of exposition and fulness of matter, to the standard of the series. Astronomy, by Mr. W. M. Cln-istie, now Astrono- mer Royal, is a useful and instructive little treati.se, not absolutely free from errors (witness the sin- gular inversion of the eflcct of bngitudc on time, in the diagram on page 14, where places west of (ireenwich have their time marked later than Greenwich time, and places east of Greenwich Iiave their time marked earlier !), but, in the main, sound. The illustration of orl)it8 of comets at page 9.3, however, is misleading. Mr. Christie explains, indeed, how and why he has changed the shapes of certain cometic orbits ; but he says nothing of tlie entire change he has effected in the positions of all the paths. It is on such erroneous teaching that the paradoxists erect their surprising structures. Jf there is one point in which books of astronomy more require re-modelling than any other, it is in this — the illustrations. The subject which, perhaps— of all treated of by science writers— most requires care in illustrating, is just the one wliich, as a rule, is most villainously illustrated. OVKBilocsE WiBEs. — There ore 9,000 miles of telograph niid tele- phone lines in the streets and on the house-tops of New York city j 3,500 of those belong to the Metropolitan Telephone Company. Theso fipircB should be n warning to our metropolitan authorities, for the number of telephone wires over liOndon is increasing at an alarming rate. The Pofit-Office has spent nn enormous sum during the past few years in converting the overhouso into underground linos. Ji-.VE 23, B2.] • KNOWLEDGE 57 WEATHER CHARTS FOR WEEK ENDING SUNDAY, JUNE 18. Sunday, 11th. Mo.vday, 12tu. Tlesday, 13th. Wednesday, Uto. ^^ -^I, Thcksday, 15th. Friday, IGth. Saturday, 17th. Sunday, 18tu. In the above charts the dotted lines are " isobars," or lines of equal barometrical pressure, the values which they indicate being given in figures at the end, thus— 30-4. The shade temperature is given in figures for several places on the coast, and the weather is recorded in words. The arrows fly with the wind, the force of which is shown by the number of barbs and feathers, thus:— * , light ; >-, fresh or strong ; > > , a gale ; j» »- , a violent gale ; © signifies calm. The state of the sea is notcil in Mpital letters. The • denotes the various stations. The hour for which each chart is drawn is G p.m. jRrbi>U)£{. "CURIOSITIES OF VECiETATION."* IN this work Mr. Cooke coquets witli the Darwinian theories. The book is interesting, and in parts instruc- tive ; but it is undeniably thin, and it wants plan and pur- pose. The author's object has been to summarise the results of the researches made by Darwin and otliers into the peculiarities of plant life, and to present their teachings in as succinct a manner as tlie subjects ju-rmit ; but he makes scarcely any attempt at classification ; nor does the reader, as he passes from chapter to chapter, recognise duly the scientific bearing of the evidence. The work reads like a note-book, rather tlian like a treatise on a scientific subject ; and, even as a note-book, portions are scrappy and valueless. The book is more likely to be • " Freaks and Marvels of Plant Life ; or. Curiosities of Vegeta- tion." By M.C. Cooke, M.A.. LL.D. (Published by the Society for what it taught us Promoting Christian Knowledge. London.) dipped into than read ; and, viewing it in tltis way, we can recommend it as one which can hardly l>e opened any- where without something of interest turning up. Kut if the book had been reduced to two-thirds of its present size (by tlio omission of such comparatively unscientific state- ments as that rattans are the terror of schoolboys, and that Krishna gamlwlled with the milkmaids of Brindabun, under the Kedainba tree), and its subject-m.attor duly arranged and sy.stematised, it would have had greatly-increased value. Still, tlie book is one well worth reading. "STORY OF A MUSEUM.'' This is a capital l>ook for young people, but also conUiins much excellent and amusing reading for older folk. The author shows what can bo done in the niatti-r of collecting objects of inten-st for a museum, when The Story of our Museum; shuwing how wo formeout in earnest. Mr. Housman expresses regret, and rightly, at the inditfercnce to natural history and science too commonly manifested by the young men of the present day. " Brought up with their eyes unopened to the wonders of Isature, they pass through life in the same state of blindness ; leisure often hangs heavy on their hands ; the country, save for purposes of sport, is Tot«d dull ; travel is deprived of some of its greatest charms ; and wisdom at mani/ entra7ices quite shut out." He notes truly how completely all this is reversed in the case of those who have imbibed an enthusiasm for study- ing and collecting, in any department of natural or historical science. Every page of this book is full of interest, from the most amusing account of the author's first attempts at bird-stuffing (the illustration at p. 35 is worth the price of the book, to our mind) to the closing chapters on antiquities and coins. This is just the sort of book to select as a present for a clever, intelligent boy. Mr. Housman's remarks on Natural History Collections (Appendix A.) desene careful study. BUTTEJlFLIES AND MOTHS. By W. J. H. Clabk. WE have now tnuraerated the principal and most generally employed methods of catching, rearing, and preserving both bntterflies and moths, but there are several others more or less efficacious which find favour in the eyes of different individuals. On the Continent, especially in France and Italy, old soap-suds which hare become putrid are considerably used, and they appear to attract moths fairly well. We have tried the plan ourselves, but op to the present only slight success has attended our efforts ; however, wo mean to give it a few more trials. Bill-poster's paste, when stale, is very " fetching," and fruit which has burst through over-ripeness makes another very good bait, especially for butterflies and other d.iy-flying Lepidoptera. The flowers of the i\-y and sallow are also very great attractions to moths, and have a peculiar intoxicating or stupefying effect on the insects, which, whilst under this influence, can be knocked off the flowers into a net without the slightest trouble. This method must bo worked at night with a lantern. Besides these, the following flowers, together with many others, are often visited by both diurnal and nocturn.vl Lepidoptera ; — The heather, mistletoe, bramble, catchfly, viper's bugloss, valerian, several kinds of grasses, scabious, honeysuckle, &c. The flowers must be well watched, and when the insect is hovering over or has settled, the net will have to be used quickly, and with precision, or failure will result. Most of the hawk moths can be caught in this way, as none of them come freely to sugar. The females of some moths also have an extraordinary attracting power for males of the same species, the " scent " appearing to travel incredible distances, and by exposing one of these virgin females in a small l>ox covered with a piece of fine muslin, numbers of the other sex will come flying round in great excitement, and settle on the box, or near it, when they can be easily taken. Probably the females of all moths have this peculiar power in a greater or less degree, but in the ca.«o of the Vaponrer (Orgijia Antiqua), the Oak Eggar(Bon.lyi QuerciM),tho Emperor (Halurnia Carpini), the Kentish (ilory (Endromifi Versicolor), and one or two others, it is so verj- marked that even a person who knows nothing of entomology cannot fail to notice it. The I'nrplo Emperor {Apatura Iris), the most beautiful of our bntterflies, and at the same time the most difGcult to capture, possesses a verj- disgusting and depraved taste, the greatest delicacy one can offer him being decomposed animal matter, and if a dead horse, donkey, (.r other animal in a state of putrefaction happens to be placed near his haunts, he is sure to descend to the feast. This noble butterfly seldom visits the ground unless under these circumstances, always flying alxiul the tops of tall oak trees, hence the diflicnlty experienced in catching him. Some people use a net with a handle 30 to 40 feet long, but it is so exceedingly unwieldy and awkward that we cannot recommend its use ; the only way we have found succeed being to wait beneath the tree until his majesty condescends to come to cartli, when a sharp sweep with the net may capture him. Light is very attractive to many moths; and if on a still warm night the windows are left open and a strong light kept burning in the room, numberless insects will Hock in, appaiontly fascinated by the glare, and the ojierutor. by standing near with a net, c!iu capture as many as ho requires. Thoy must, if possible, bo taken imme- diately on entering, as, if not, tho wings are sure to become more or less injured, owing to the frantic efforts of tho moths to get to the light. Going round to tho street lamps from about eleven to one o'clock at night is often very productive ; and if half-a-sovereign or so bo given to tho man who extinguishes the lamps, and a supply of chip boxes, with instructions to catch and bring to you all tho moths he finds, very many rarities will bo obtained, and a considerable amount of trouble spared. If any particular species is desired, tho most likely spot for its capture is tho tree or bush on which tho caterpillar feeds, as the female moth, impregnated or otherwise, always flies about in its neighbourhood, and the males aro generally not very far off. All the above-mentioned methods aro in use, and are accompanied with a gi-eator or less share of success ; but for moths, nothing comes up to "sugar" in attracting properties, as far as my expe- rience goes, and 1 should advise collectors to stick to that and the street lamps. Immediately on seeing Mr. Mattieu Williams' communication in No. 32, page 27, wo gave the bisulphide of carbon a trial. The victim, a large Puss Moth {Cerura Vinula), was placed in tho vapour as directed, for tho space of five minutes, and when taken out was quite dead. This method appears to us to bo very good, as insensibility ensues almost immediately ; and though death does not come on so soon as by some other means, yet tho insect cannot flutter about, which is a great consideration. There is one great obstacle attached to its use, that is the exces- sively unpleasant odour which it possesses; and, as tho liquid is remarkably volatile, this properly soon makes itsc'lf evident. Wo thank Mr. Williams for tho information, and for tho future shall always keep some of the li(iuid in tho house ; wo advise our readers to do tho same. TiMK SiGVAl.i.iXG.— The following information, relating to time signalling in England, is taken from the report of the Astronomer Royal for 1881 : — " There has been only one case of accidental failure in the automatic drop of the Greenwich time-ball. On four days the ball was not raised, on account of tho violence of the wind. The Deal ball has been dropped automatically at one hour on every day throughout tho year, with tho exception of fifteen days, on which there was either failure in tho telegraphic connec- tion or interruption from telegraphic signals continuing up to one hour, and of one day when the current was too weak to release the trigger without the attendant's assistance. On three days high wind made it imprudent to raise the ball. Tho Westminster clock has continued to perform well, its errors having been under one second on 40 per cent, of the days of observation ; between one second and two seconds on 44 per cent. ; between two seconds and three seconds on 14 per cent. ; and between throe seconds and four seconds on 2 jjer cent. Time signals originating in the Observatory aro distributed at 10 a.m. to all parts of tho country by the Post- Offico telegraphs." A PiiENOMBNAL CANARY.— The power of imitation possessed by birds of the parrot tribo has long been familiarly known, and it would not be difficult to find numerous examples of even well- educated members of the genus in this respect. Wo do not, how- ever, usually regard the vocal powers of canaries as being equal to the production of articulate sounds resembling those made by the human voice. Hut there is at ])rescnt in tho possession of Dr. J. Mefjrigor Croft a little songster of this description, which, besides giving utterance to delicious warblings, is also able to " talk " with a clearness and precision simply marvellous. Somewhat sceptical of the accounts we liad rec.;ived of this animal wonder, wo have, through the kindness of Dr. Croft, had an opportunity of directly proving the truth of tho statements made concerning it. Tho canary does veritably speak, and enunciates a number of sentences which are clearly imitative of tho voice of the lady who has had care of it since its early youth. Tho effect, indeed, jirodiiccd by tho clear, sweetly-uttered sentences pronounced by tho bird is almost weird at first; but tho feeling of wonder thus created quickly gives rise to a sensation of exquisite pleasure, which is deepened as the little creature suddenly at the end of a sentence rushes off into an ecstacy of song. As illustrating tho exquisite pliability of tho laryngeal apparatus of small birds, and the extent to which training may be carried in such cases, the tiny animal is deeply interesting to physiologists. As a mere curiosity, however, it is undoubtedly unique, and wo are deeply obliged to Dr. Croft for having been enabled to witness so phenomenal a bird. — Medical Press. 1882.] KNOWLEDGE ♦ 59 2.cttfi£» to ti)t (BhitOV, fnk* Editor doei not hold himtelf rttpontibU for the opinions of hit eorre*pondenU. Be cannot undertake to return manmeriptt or to eorreipoud ttilh Heir ttrileri. All eommunieationt should be Of short a* foesible, consistently teitk full and clear state- wtents of the teriter's meaning,'] All Editorial eomntunieaUons should be addressed all Business communication* to tk* I*ublishers, at street, W.C. All Remittances, Cheques, and Fost-QMee Orders should be made pavabU to Messrs. Wvman S, Sons. •,* All Utters to the Editor scill be Numbered. For convenience of reference, correspondents, vhen r^erring to any letter, «\ll oblige by mentioning its number and the page on sthich it appears. All Letters or Queries to the Editor tchich require attention in the current issue of Kkowlidsb, should reach the Publishing Office ntt later than Ike Saturday preceding Ike day cf publication, ______^ (I.) Letters to have a chance of appeariDp must be concise ; they most be drawn op in the form adopted for letters here, so that thev may go untouched to the printers ; private commnnications, therefore, as well as queries, or repbes to queries (intended to appear as such) should be written on separate leaves. (n.) Letters which (either because too long, or unsuitable, or dealing with matters which others hare discussed, or for any other reason) cannot find place here, will either be briefly referred to in answers to correspondents, or ackuowledged in a eolonm reserved for the purpose. ** In knowledge, that man only is to be contemned and despised who is not in a state of transition Nor is there anything more adverse to accuracy than fliity of opinion." — Faraday. "There is no harm in roakinp a oustake, but erreat harm in mating unue. Show me a man who makes no mistakes, and I will show you a man who has done nothing." — Liebifj. " God's Orthocloiy is Truth."— CJar/w Eingiley. TOBACCO AIsD COXSUMPTION. [431]— In mentioning the immunity of the Turks from consump- tion, Mr. W. B. Wicken (411) has not noticed the fact that the Turkish women have never '■ taper waists." If all the females of cattle and horses were deformed, would any sane person expect them to produce healthy or "sound" offspring? Now, fully 90 percent, of the women here are so deformed. From the practice in youth of wearing stays and glove-tight dress bodies, their lung- capacity is reduced, and all sorts of morbid conditions follow; yet so strong is the force of habit, that the majority of the world expect to find the children of such mothers healthy and unpre- disposed to consumption, and the scientific even cast about to try and discover some far-off and occult reason for the most natural result! The marvel is that the nation is not more unhealthy. Rather let them u.sc their influence to try and persuade young men and women to stuily anatomy, and to go and look at the statues in art galleries, and instead of calling a woman's natural figure "clumsy," to fi.x that epithet on a dress which makes it appear so. They will see there, also, that legs are no more exclusively masculine than arms or fingers, and tliey may in time begin to draw the ioference that a style of clothing which, from its innate ngliness retiuires the sacrifice of health and strength to make it presentable, is not the most advisable to persevere in upholding, it they wish to preserve the supremacy of their race, and to stamp out long disease. — I am, Sir, ic, F. W. Harberto.v. [432] — Tliere are no returns showing tho relative prevalence of coDsamption among the smoking and non-smoking males of this country, but some idea of the influence of tobacco may bo obtained by comparing the deaths from phthisis of males (of whom, perhnp.s, one-half are smokers) and females, who are, practically, nil non- smokers. The deaths from phthisis in tho year 1876, for example, in England and Wales were 30,413 males and 35,221 females. The occupation of men is tho chief cause of tho greater prevalence of phthisis among them, but, if tobacco had any practical power of averting it, wo ought certainly to find its frequency less among men than among women. J. J. Kipgf, M.D., B.A., London. MULTIPLICATION AND DIVISION OP DECIMALS. [433] — With your permission I venture to submit tho following facts relating to this subject to your arithmetical readers, with an apology if it happens that I am telling them anything that they already know. Arithmetic is an exact science, and, therefore, does not entertain the idea that when applied to calculations based upon measure- ments, it is working upon a more or less erroneous foundation. As a matter of fact, however, all measurements are necessarily approii* mations. If we reckon in the decitiial notation, our measurements will be correct to po many decimal places, and no more. Suppose then that we require to multiply the numbers 3G12-219 and 3141, both of which being correct to the third decimal place, the error in each factor (duo to the fourth, fifth, Ac, decimal places being un- known) will cause corresponding errors in the product ; but the fact is evident, that the error in the second factor (3141) will cause a thousand times more mischief than the error in tho first factor, for it is multiplied by a number a thousand times larger than is the case with the other. Is it not wise, therefore, to cut down the first factor to the same number of digits as the second, and multiply 3,612 by 3,141 ? Again, since the product of two approximate numbers can never be depended upon to more digits counting from left to right than there are correct digits in either factor, will it not be wise to sub- stitute cyphers for all digits beyond four in the product of the above numbers, and write 1134<:>, instead of 11345-292? This makes our results appear to be often only very rough approxima- tions ; but what is the use of deceiving ourselves ? 1 have seen the heating surface of a set of boilers calculated in square feet, and tho result published to tico decimal places, when a moment's considera- tion would show that an error of only one-hundredth of an inch in the diameter of the tubes (of which the heating surface mainly consists) would vitiate the result to the extent of twenty or thirty square feet. Logarithms appear to have this advantage over ordinary arith- metic, namely, that they naturally fix the degree of accuracy as wel! as the value of our results. Logarithms put ns to a lot of trouble if we attempt to get more figures in our answer than are good for us. — Tours, &c. A. N. Souesscalks. [434] — Supposing that the reader has leamt how to reduce a vulgar fraction to decimal form, i.e., how to divide one integral number by another not contained "exactly " in it, and to carrj- on that division beyond integral quotient figures, and that he accepts the truth of the statement, that " if the divisor and dividend be both multiplied by any the same number, the value of the quotient is unchanged"; " then the rule for division of decimals is, " mnltiply the divisor and dividend by such a power of 10 as will remove all decimals, and divide tho latter ))roduct by the former." I take the examples given in Knowledge, May 0, p. 576 : — 127-412) 15-315 1000 1000 127,412) 15315-0(-12020C6 127412 2573S0 254824 255600 251S24 776000 76-4472 11528 127-U2) 1531-5 1000 lOOO 127412) 15315C.0-(12-02 127412 255600 254824 776 From the above the following rule at once suggests itself: — 1. If tho number of docimal places are not equal, make them equal by annexing zeros. 2. Then divide as in whole numbers, neglecting the decimal points in division and dividend. So far, tho quotient will bo integral. 3. Any quotient figures found by annexing leros to the dividend, or remainder, beyond this point, will be decimals, but the only re- 60 ♦ KNOWLEDGE [Jdne 23, 1882. commendation it has is that it saves the trouble of writing the figures down a second time. W. Mathus. The School, Bidefor»l. PS— You will observe thnt 1 reverse the usual order of things. In all ariihmetic text-books that I am acquainted with, division of decimaU fr«fd« the rule for reducing a vulgar fraction to o «lecimal, whereas division of decimals might aptly and naturally follow long division. — W. M. r435^ I sec, in ans\ver to a correspondent "Euclid," of Bolton, (Knowledge, Xo. 31, p. 13), a reference to a large fire-ball, or meteor, seen on May 4th last, at 9.30 p.m. I saw it, and as you indicate that more information on the subject might be useful, I Tentnre to give von mv version of it from notes made at the time. C was searching' with inv telescope for i^- Cygni, when suddenly the field of view was lit up, and the stars in the field vanished as if davlight had suddenly returned. On taking my eye away to ascer- tain the cause, there, right in front of me, was a great ball of intense white light, apparently almost as large as the full moon, gliding across the sky. It travelled so quickly that it is almost impossible to name its eiact path, but when I first saw it it was about on the head of Draco. It passed over Cephcus and into Cassiopeia. In passing over Cepheus its colour changed from white to red, and near y Cassiopeia*, it again changed to blue, or violet, gave an extra flash np and instantly vanished, leaving behind it a long train of red sparks, which died out by degrees, and which had previously been invisible in the intensity of its light. The whole phenomenon did not occupy more than two or three seconds of time, and there was no perceptible noise. It lit up the whole sky like a lingering flash of lightning. It certainly was an awe-inspiring sight, and I heard many people in the neighbourhood, when it was taking place, give vent to their feelings in a shout of amazement. I never saw anything approaching it for grandeur in my life. Excelsior. [For the purpose we mentioned, " that is, to determine the true path of the meteor in our atmosphere," it would bo essential that the exact course of the meteor, as seen from our correspondent's station, should be indicated, but his letter is independently interest- ing.— Ed.] FLINT IXSTRUMEXTS AXD PRE-HISTORIC MAN. [43C"— A friend of mine, who has just returned from Natal, and ■who had heard nothing of the discussions and theories on the above subject , and on whose veracity I can thoroughly rely, has been «mployed in making the Durban and Mnritzburg Railway. In con- versation the other evening, he told me that in making the Umgeni cutting (through red loam, gravel, and limestone rock) at It feet from the surface, from which a dense forest had been previously cleared, in the red loam his Kaflirs came upon the remains of a fire, charred sticks, A-c. ; close by this he found what he describes as a well-made and beautifully-finished flint odzc-head, the cutting- face sloping from one comer to the other, witli a bevelled edge like a chisel, and the other end finished off with a round flat knob. Again, at 10 ft. from the surface, in the hard gravel, he found a jjood manij flint instruments, the two most remarkable ones being a round stone, about the size of a largo orange, very much flattened at each pole, with a { in. hole drilled through it, and by the side of it a stone handle 7 or Sin. long, one end just fitting through the hole, and the other end rounded off ; when put together it had just the appearance of a small stonemason's mallet. At a short distance from this was a stone quoit, almost exactly like the iron ones nt present in use, except that, from where the imlentation for the thumb is, the circle was cut straight across, for about quarter of the circum- ference, by a round handle. The whole of these curiosities were taken possession of by the engineer of the line. When tlie geological formation of Natal, and the pretty well- founded idea that the whole of the country has been denuded by a frTcut out-ruHh of waters from a great lake once covering nearly the whole of what is now the Orange Free State, is considered, wo are compelled to give an antiquity to the possessors of these implements as great 'as, or even greater tlian, that given to similar tribes of men in Europe. W. M. THE POTATO. [137]—" Farmer" (105, p. Oil) asks me whether I advocate the n«c of mineral mannres to increnKC the starch in potatrH>g. I take it for granted that by the term " mineral " is meant potash, salts, Ac, without reference to sujierphosphates. My own experience (not at neoond-hand) indicates that the percentage of starch, as found ander the influence of " supers," is reduced by potash salts ; but the land on which I operated was naturally well supplied with potash, so that only a guess can be made nt the probable results to be obtained on land poor in that element. Marcker finds but little effect on the starch from any manure. I can give no information concerning the effect on the iier.-entage of starch in cereals exerted bv "minerals." " Farmer" is somewhat hard on "F.C.S. ' when he says that it is nonsense that stable manure is not better than peat ;' therefore I add for comparison the analyses of a sample of peat and of farmyai-d manure : — Farmyard Manuro. Poat. Porconl. Percent. Onranic matter 78H 77.0 Mineral 33 3-0 Potash 015 007 Sulphuric acid Oil 020 Lime 0-2 025 Nitrogen 058 0 99 Another sample of peat contained less nitrogen, but nearly double the amount of potash. Chemically speaking, this peat was in many respects better than manure, but the agriculturist would probably not consider it so, because he would find that the fibre of the peat would take so much longer to rot ; also the nitrogen of the farm- yard manure is in a more assimilable condition than that of the peat. It is much to bo regretted that the scientist so frequently makes a statement which, though correct ill itself, requires some further explanation before it becomes intelligible to tho public, who, being unaware of the full facts, proceed to judge upon tho matter. Because 1 fancy that this has occmroil in tho jiresont instance, I have added this short explanation, which will, I trust, qnie^^ •■ Farmer's" mind on the subject of peat, and also show that F.C.S was correct in what he wrote- although, I daresay, ho is perfectly well able to take care of himself, without my saying anything. A CALCULATION. [-438]— A solution to tho following question would oblige one of member.", for the purjmse of vancmg a sum of £500 to each ...^...bor for a term of 124 years, free of interest. Subscription of each member £12 per year, repayment of loan at tho rate of £40 per year : how long will it be bifore the final member receive his advance? Pyuami-s. Liverpool, May 23, 1882. GOLD IN INDIA. r439] — Much has lately been written anent the, at present, dis- puted existence in India of quartz that will, on proper treatment, yield gold in quantity. Will one of your scientific friends who knows tho regions there at present under exploration, give me, through your medium, his opinion on the subject ? This question interests many, if not all, of your readers.— Yours faithfully. INSTINCT AND REASON. [440]— May not instinct in the lower animals and reason in man be the same, with this difference— that the one is more intense in character, tho other wider in range ? And may not this difference bo accounted for by the fact that, whilo the brute does one thing a thousand times, we do a thousand things once ? SiLcnESTER. "ATTLD RoniN GRAY." [•Ml]-!"' -!■ ■ I In ' ■; :• the subject of music lies within tho scope of Is I ' ' N 1 hoDO that you will throw some light ontho(lis|i ' , ilic. nu'thorship of tho melody associated with tho Will t \ii:urse-strings. — G. T. M. E. Thanks. — H. E. Kilbv. Yes; that method, like the others, is theoretically sound, bat practically unavailable, because of the relative smallnees of the moon's dis- tance. Very small errors in determination of longitude and latitude of stations, and of times of contact, Ac, would introduce very largo errors into the estimates of the sun's distance. The conception is. however, very ingenious. — Erix-go-Bk.igii. It is the case some- times ; so also old hens are adorned occasionally with imperfect sort of comb, and some old ladies with monstachios and beards. — A. BiTTi-E. The Leprosy communication did not seem quite so generally interesting and important as that on Tubercle, and our space ran short.— W. Geaxdy. Thanks for encouraging letter. On the other point, I can assure you I would gladly see my books sold at very low prices ; but publishers, with whom the matter rests, cannot venture — yet, at any rate. — A. E. W. Our arrangements for indexing already made when your letter received. — F. Morris. Berry's Polishing Paste and Domestic Black-Lcad are rather outside our lines. — T. (Jreex. Do not know of any book or books on Gum, its properties and uses. BOTANICAL. E. C. H. (Worthing). Host cultivated " geraniums " belong really to the genus I'elargotiium, which has slightly irregular flowers (two upper petals differing from three lower), a spurred sepal (scarcely noticeable), no glands, and few stamens (generally five). The true Geraniums have regular flowers, no spurs, five glands on the disk, and ten stamens. A few perennial true Oera- niums from southern Europe are still cultivated in old-fashioned gardens, but most of the plants so-called are I'elartioniums from the Cape of Good Uope. I'dargnnivm U, in fact, a larger and more specialised insect-attracting type. When in doubt, look for the irregular sepal and count the stamens. Gba.nt Allen. -ELECTRICAL. Igxuuamis. See article in Kxowlepge, Xo. 30 ; ebonite can be procured from the India-rnbber and Gutta-]x>rcha Company, ICO, Cannon-street, London, E.C. The same article (see also errata, No. 31) answers your (juery anent length of wire. The generator de- scribed will "make a current quite strong enough for plating — ii» fact, rather too strong in proportion to its other features. It will not be strong enough for a .Swan lamp, which rec|uires an electro- motive force of forty volts, or the force produced by twenty good Bunsen cells joined up in series. — U. Bardslev. Get a glass or earthenware jar, about three pints capacity, into this put a xine rod for the positive element. The negative element is a small carbon ))late placed in a porous pot, filled up with a mixture in equal ]>arts of crushed carbon and black oxide of manganese, about the size of parched-peas. Great care is requisite in making this part of the cell, and yon would find it cheaper to buy — well, the )>orous pot with carbon plate in situ. A saturated solution of sal ammo- niac is put in the outer jar, half filling it. At Silvcrtown, where these batteries are made in very large quantities, the upper ex- tremities of the carbons are dipped, at a high temperature, into melted paraflin, and subsequently placed into a mould containing molten lead, which forms a cap for the carbon, a brass terminal being simultaneously fixed into the lead. Marine gluo is run over the carbon-manganese mixture, the carbon rod being in position. Vent-holes are made in the glue to allow any gases to escape. M\ bare metal connections must bo well coated with pitch or varnish, otherwise they will soon be corrodml by the gases given off by the battery. Should you buy a coll, I would n-commend the new- agglomerate LecIanchiS w'ith u largo zinc cylinder, instead of the zincrwl. There are at the present moment some thou.ected. Tli- rlmrv-.-a will in this case be considerably reduce*!. ♦ KNOWLEDGE • [June 23, 1883, ^ir i«att)fniattral Column. THB LAWS OF PROBABILITY (Conduced). IT 8houlJ be noticed, in the first ]>lacc, that in dcalin,? with hjr)M>theses, wo must consiiier their aiiteco Jent probability ns well aa the cviJence derived from observed facts. We Bomotimcs hear the contrary course spoken of as the perfection of philosophic reasoning. " I will not suffer myself," some will say, " to consider whether this or that hypothesis is likely or not ; I only desire to know whether observation and experiment appear to favour it or the reverse." This i.i an exaggeration of a principle which is exooUcnt in it«elf. Doubtless observation and experiincnt should bo the test by which every hypothesis is examined j and in the long-run, ob- Eer\-ation and experiment may serve to over-balance any antecedent probability against or in favour of an hypothesis. But during the progress of research, and while ns yet the evidence derive! from obsen-ntion or experiment is not decisive, it is essential to tho formation of the most probable opinion that antecedent proba- bilities shoald be duly weighed. For example, let us suppose that a person submits to my notice three predictions con- cerning tho weather, founded on tho planetary positions, and fal611od in a very striking manner by the event. Let ns suppose that the predictions are couched in tho clearest possible terms, and are such that tho odds must be regarded as heavy against their accidental fnlfilment — say, 9 to 1 tor instance. Then the chance that all these predictions ivill bo fnltilled, if the hypothesis of planetary influence is erroneous, is jTJjJn > °^ the same as that of drawing one particular ball out of a bag con- taining a thousand. And tho fact that the predictions have actually been fulfilled seems, therefore, to afford very striking evidence in favour of the hypothesis that the planetary positions do actually influence the weather. If I overlooked tho antecedent probabilities of the hypotheses (1, that the weather is so influenced; and 2, that it is not), I should calculate tho probability of the planetary hypo- 1000 100 1' But this would bo to forget the main porlion of the evidence, that, namely, on which our opinion of the antecedent probability against the planetary hypothesis is based. I do not enter into consideration of this evidence, bnt undoubtedly it is of such weight that the most surprising scries of fulfilled predictions (even though accom- panied by clear evidence that not a single prediction had been unfulfilled) would scarcely justify ns in ev(« giving the hypothesis consideration.* It is necessary also to consider most carefully whether we really have before us all the possible hj-potheses by which observed facts may bo explained, and whether the various hypotheses are mutually exclusive, for otherwise the general theory above cnunciatid is not applicable. As an instance, let us consider the views of Dr. Stark re.?pecting the influence of marriage on the death-i-ate. From the olJ«er^■ed mortality among married and unmarried men (the fori-icr class including widowers). Dr. Stark was led to infer that marriage is favourable to longevity. (The statistics are given in my essay on the subject in " Light Science "). In arriving at this conclusion, he took only into account tho particular hypothesis that the observed inferior value of nnmarried lives is due to bachelorhood. The hypothesis that marriage is favourable to longevity is not unlikely. in itself, though, certainly, the very marked difference con- sidered by Dr. Stark seems more than tho liypothesis can account for. But there is another hypothesis of which Dr. Stark took no account whatever": tho superior value of married "lives" might Ix! due to a principle of selection, whereby on tho average of a great naml>erof persons, the healthier and stronger would be found in larL-'-r proportion among tho ranks of the married than of the nnmarried. The neglect of this hypothesis vitiates Dr. Stark's reasoning altogether. Tho consideration of this hypothosis, to the neglect of tho other, would be .-ilso incorrect. Both hypotheses must tx! considered together, with duo reference to tho antecedent probability in favour of each. But as they are not mutually ex- clniive, we cannot apply to them our general rule. Wo can only infer that cither one or the other is the true hypothosis, or else that »X)th hypotheses are partially true ; and this does not lea%-e us three cases only to consider, lierauec the causes dealt with by tho hypo- theses may co-exLst in different proportions. Tho statistics dealt • Such an assertion aa this seems incomprehensible to tho paradox mongers (as Do Morgan used to call those who propound Buch theories aa wo aro considering). " Strike, bnt hear," they •ay, and they wonder that none will hear, and that few even think it worth while to strike. with by Dr. Stark are, therefore, not capable of loading us to any dehnite conclusion. But it is not to bo inferred that in this case, and in other similar cases, the statistics are valueless. The fact that they point to no dctinito conclusion sliows only that they aro insuthcient. Other statistical information may so supplomeut snoh imporfoot know- ledge as to lead to tho deliuite conclusions wo require. And tho consideration of imperfect statistics usually shows us in what direction we aro to look for supplementary facts. For oximple, to return to Dr. Stark's statistics. Wo have seen that thoy aro in- sutficient in themselves. They point, however, to two hypotheses, and we have only to detcrm'ino in what degree the two causes dealt with by these hypotheses actnally operate, to form a sound opinion on tho whole subject. I am not concornod, bo it noted, with tho practical application of such inquiries, only with tho bearing which they would havo on tho special qiiestion considered by Dr. Stark. Now, if we study tho statistii-s relating to tho number of marriages in times of prosperity or adversity, or, again, in healthy and unhealthy seasons, wo should gain some slight in- sight into tho i)robability of tho action of a principle resembling selection. Wo might obtain statistics, again, as to tho trades of those who marry, so as to compare tho number of married and single in the different trades. Other statistical inquiries (which might bo very diflicnlt to carry out in practice, however), such ns inquiries relating to tho insurance of married and single, to tho health and strength of each person throughout his life, and so on, would throw further light on the subject of inquiry. Under the actual circumstances, wo can only form probable inferences on these subjects, but the conclusion wo arrive at is much more likely to be sound when such inferences are consid"red, than when no attention whatever is paid to one of tho possible causes of a result so in- teresting as the superior longevity of tho married. Another circumstance to be very carefully considered is the actual number of cases with which our statistics may deal. It is impossible to aj-rivo at correct conclusions unless this number is eufiiciently large. Quitelet has related how a person assured liim that a certain street in Paris was tho healthiest region, not only in Paris, but in Franco. When Quelclct asked how this extra- ordinary conclusion had been arrived at, liis-informant remarked that Quetelet's own method of statistical research liad been applied : " I liave found that more than two hundred persons live "■ that street, and tl;cre havo been only three funerals in three the doath-rato so low aa suppose, then," answered Quetelet, "that if there had been no funerals at all, you would havo concluded that by removing to that street you would live for One point remains to bo touched upon. I have spoken of the fact that in any very great number of trials, series of events may bo erpccled to occur which would appear very surprising if they happened in bnt a few trials. It would bo a mistake, however, to infer that the occurrence of a strnngo series of events is to bo regarded as on that occount less worthy of notice. Boswell related that when he mentioned to Dr. Johnson that tho first of tho new hackney-coaches which ho had seen had been actually No. 1, tho Doctor ridiculed tho notion that there was anything remarkable in the coincidence. " You were ns likely," ho rea- soned, "to see that coach as any other." Now, althongh Dr. Johnson was certainly right in this instance, yet it would bo a mi-stako to conclude that such coincidences in general should bo overiooked.» When a coin is tossed, it is as likoly that twenty heads will bo tossed in succession ns that any other specified arrangement will appear; yet undoubtedly if tho event had hap- pened wo should bo justified in suspecting that a two-headed com had been used. If a die is cast twenty times, and ace appears eight times, wo might reason that the observed succession of throws wiis antecedently as likely as any other particular succession, and this reasoning would bo just; but, unquestionably, if such an undue number of acos appeared, wo should think it not unlikely that tho die was cogged. This opinion would be strengi honed if aco was a • QuMelot relates a curious story illnslriting this ; " During the first Spanish war, n corps of tho French army, which was employed in tho siege of a town, dreaded tho rccuiTenco of Friday, as a day fatal to it, because tho enemy killed or wounded then more of their men tlinn on any other day of tho week ; a strong prejudice was, in consequence, established against Friday. Now after tho siege, it appeared that tho artillery had been changed every day, and that those who did duty on Friday wore superior marksmen to tho others. Superstitious ideas," adds Quitolot, "have often less foundation; from tho impossibility of discovering the true cause under the circumstances in which wo aro placed, wo aro apt to attribute thom to objects totally extraneous, not being willing to I consider effects as existing without a cause." years. Now, in what part of Franco is five per thousand per annum ? " "I JtrwK 23, 1882.] • KNOWLEDGE • 63 throw by which money was won. Withont deciding at once that we were being cheated, we should watch somewhat carefully to see in what proportion aces appeared thereafter. So it is when, at card games, a player secures more frequently than probability warrants some favourable "hand." There must be players who eeem lucty on occasion, and there vmst be some who appear exceptionally lucky for years. But this should not cause the player to blind himself to the antecedent improbability of definite runs of luck, and therefore he should not overlook the necessity for watch- fulness when they have occurred. And lastly, in those affairs of ordinary life in which chance plays a more or less prominent part, but conduct yet counts for something, we are justified in inferring skilful conduct where good fortune is long continued and strongly marked. '• In the conduct of life," says the great mathematician Laplace, " good fortune is a proof of skill which should induce us to prefer placing our confidence in those who appear thus lucky." (Bur Cf)cs(5 Column. By Mephisto. THE VIENNA IXTERXATIOXAL TOURNAMENT. THIS week will see the finish of the Tournament, as on WcdtiCiJay , probably, the last game will have been played, and then the Chess world may devote itself to the task of honourin? the \ictor AVho this would be formed the subject of conjecture and conversation in London Chess circles. Steinitz, who had been doing badly in the beginning, gradually crept to the front, till on the twenty-siTth round he came out ahead of all other competitors. The public like to pin their faith to tried men, and it was generally then taken for granted that Steinitz would come out as chief winner. This belief was, however, dispelled by the news that arrived from Vienm, which showed that Steinitz had relapsed into bad luck, w hile Mason was doing wonderfully well and carrying everything before him According to telegraphic information received in London on Thurs- day, Mason was at the head of the list with 20, while Steinitz stood at 19i. It was then generally believed that Mason would win first prize, and bets were freely made on that expectation. We hope to be able to publish telegraphic information, before going to press, as to the actual result. According to a telegram in the Daily Telegraph, of Monday, the following was the state of the score on Saturday night, Juno 17, after the conclnsion of the Slst round : — Mackenzie, Steinitz, and Winawer, 214; Mason, 21; Zukertort, 20^; Blackbume, ISJ ; EngUsch, 17J ; Paulsen, 16i ; Wittek, 16 ; Hruby, 141 ; Weiss, 14 ; Schwarz, 131 ; Bird and Tschigorin, 12; Meitner, llj ; Ware, 10. The committee have thought fit to alter the order of the play on Thursday last ; we cannot therefore properly estimate Mason's score, as it is quite possible that in spite of his being half a game behind, his position might be as good as that of any other man. The close- ness of the five first men makes the finish a very e.\citing one. On Monday Zukertort beat Weiss, Paulsen beat Ware, Hruby beat Mackenzie, Steinitz v. Bird drew. Mason was engaged with Englisch, and Winawer with Meitner. Problem Xo. 4-5 l!v I!. 0. Laws. ,. i i i W .-~N J 80LDTI0NS. Problem Xo. 42 by J. A. Miles, p. CI 5. 1. E takes P (ch) 1. K to B5 2. Q to KG 2. R takee Q 3. Kt takes K (mate) or if 2. K to Ktl 3. Q to R6 (mate) or 2. R takes R 3. Q takes R (mate.) Bv J. Licence, p. IG. No. 43. No. 44. 1. Kt to K4 K to Q4 I 1. P to K8 B K to K3 2. P to Kt8 R K to K4 2. R to B6 (mate) 3. R to Kt5 (mate) The following two pretty endings are from the t ield .— Blackburne. St.ini,.. w. n rr^r^ r"~ "6 11©- i kt t ti . t i J.I t i ^ mmM. k i mwrm t i m^w p"^ . 7JA 'H- 'M> KS 1 ■ 10^ ^ #«■ jBim m^'...- - m _iS ■ ■ WHITH WHITI. Wiiwwtr BlK^ibame. The fmm^ pr(xced^d th ^ — WUIIE. BLACK. R takes Kt B takes R KtloQ7lch) R takes Kt U takes R R to Qsq B takes P BloB2 R takes P(ch) K to Bs(| H to Ktsq Q to E-i ; and here BlackbDme made one of his ma^ificent coups. He answered R to Kt8(ch). Of course, the K Tras bound to take, and then followed Q to QKt4(ch) , and White's Q wa« lost. The came broke down soon afterwards, and Winawer resigned on the .'>2nd move, after oi houra* plar. «apoB "4^ In the position pren in the i White plaved Q to R3. Sleinili~< pletelv t.Terlooked the ineenioaa derice, and answered R to Blaekburne won the Q. bjr R to Of course, Steinili was bou " for mate was threatened KtProh), and the Maek Q iraa there- fore lost bv Kt to R6(rb). The proper answrr for Itlaek in the position eiven was Kt to K4, with the view of fianx himself at Qft, even if While attacked the R by Kl to Qii. Black would have bad a fa'ir game then at the cost of the exchan^'e for a pawn. ANSWERS TO CORRESPONDENTS. »,* Please address Chess-Editor. W. I<. Lambert v. Edward Wilson. Novice. — We cannot find any fault with our score of game p. 033. There is no Queen's Pawn to take White's Knight or liishop, as the Queen's Pawn has been captured by White "iii pass" on his third move. Move IR, p. 634, it ought to"be Q takes Kt. Correct solutions of Problem received : No. 42, by Berrow ; Nob. 43 and 4t. by C. S. Bright, Genoa, Brenton, J. Russell (something). S. M. — It "is not so. J. Tilbe. — To castle after check has been given, is allowed. %\Tiite to play and mate in three mores. A RVP.iRT (just issued, Imt dated Oct. 21, 1881) on the incao- dcjcent lamps exhibited at the Pnri.^ Exhibition (1881), has beoH Iircpcntcd by Professor W. Crookes and O. F. Barker, who wore appointed a 'sub-committee for the purpose. The testa have l>ocn carried out in an exhnnstive manner, and it will bo ninttor for very groat regret if a similar rop0Rl,'and if they gain the d.iy. th.-y w.ll hold almost exclusive sway in matters telephonic. Professor Sylvnnus Thompstm, writing to the Times, asserts, however, that the IVilboiir system, so nblv iKscrilied bv Professor Dolbear himself b«»foro tho Society of Torogrnph Engiiieors, a few weeks since, is tinnfTectcd by tho dooi- sion. The principles differ considembly from those of tho ITnitod Company's apparatus. 64 • KNOWLEDGE [JoNE 23, 1882 (J?ur 2B\)i$t Column. By " Five ok Clubs." PLAY TUIRD IN IIANP, I'LAl.N SUITS (continued). WHEN, third in hniul, you liold Queen or Kimvo and others, and a email card has been led which second player does not cover with a card liij^her than your honour, you must in orer)- case play the honour. But if ton is led, and not covered by Knave, yoQ n-onld not play the Queen, but pass the ten ; for, as already explained, you lu'ain nothing by plnying the Queen if the load is from Kinp.Knave, ton, while, if the ten is a strengthening card, you lose all command of the suit if you cover. If you hold Knave, nine, and others, and eight is IcmI, you may line-'so the nine or i)as8 the eight ; eight can hanlly be played as a strengthening card, nor from a three-card suit, containing both Ace, King, or King Queen, for from cither of these combinations the proper lead is the King. If the eight is the lowest of a foor-card suit, the suit can be no other than Ace, Queen, ten, eight. If the lead is from a three-card suit, the eight being the lowest, the other cards may be Aco Queen, Ace ten, King ten, or Queen ten. The ten can therefore only be to your left in the single case of the lead being from Aco Queen eight — which is an unlikely load anyhow, though, of course, jiossible, since leader may hold besides four trumps, and two weak three- card suits. Vou are therefore, in all probability, quite safe in lineFsing the nine or passing the eight according as you may wish the lead to lie (supposing the trick to fall to the eight or nine). When, ihird in hand; your best canl is small, yon play it, of course, if it is higher than the card played on your right, or higher than and not iu sequence with the card led. If you cannot cover, and both the cards already played are small, remember that your card tells both your ])artner and your adversaries of extreme weak- ness, both in individual cards and numerically. In such eases the question may arise sometimes whether it may bo better to deceive the enemy or not by playing a false card. For instance, if your partner leads four, second hand plays sis, and yon hold three and five i if you jihiy the live, it will be thought that you do not holil any other cajd in the suit. Cases may arise where it may be more im- portant to cause the adversaries to suppose this erroneously, than to leave them and your partner in doubt by playing the lower card. It is worth your while in ever>- such case to consider which is likely to be the more advantageous course. The play of third in hand, second ronnd of a suit, depends gene- rally on the fall of the cards. As a rule, you know pretty well how the cards lie at this round, whether the original lead wore your partner's or your own. In the former case you have the indications from the original load, as already explained ; those from the play second and fourth in hand, those from the renewed lead, and play second in hand second round, besides your own original hand. In the latter, as the suit is presumably your longest, you have rather more information in your own hand than in the other case, and rather less from the play -, but if yon have been watchful you have usually learned a gooil deal. Thus, suppose, having King and throe other clobs 10, i, 3, yon lead the 3, and the cards fall thus, — C3 C8 CQ CG you know that, apart from signalling for trumps, your partner must hold the two and five, second player has nothing below the eight, fourth player nothing below the six. N'ow, suppose that on the return of the suit your partner lead.'< the two ; then, as this is not the highest left in his hand, yon know that besides the five he has one other, which is not the Ace, for if he ha/l had the Aco ho would have led it. Xor can it be the Knave, for if he had had Qaeen Knave, ho would have played the lower of the sequence. You hold the King your- self, therefore his remaining card must be either the seven or the nine. Yon know this Ijefore second hand has played to second round. You know also that second hand has not the Ace, or he would not have allowed the Queen to take the first trick. Suppose, now, second hand plays the nine. Then the only card whose ]>osition remains doubtful is the Knave ; it may Ije to your right or to your left. But you can piny with as much confidence as if you knew whore it was. For if it lies to your left along with the Ace, which certainly lies there, yon lose nothing by finessing the ten ; and if it lies to your right yon gain n trick — apart from rulKng. Take again the following case, — Yoor hand being Q, Kn, 5, 2 of Hearts (trumps), the first round is — A. Y. II. Z. H 2 n 9 UK II G Second ronnd, to second in hand, is let OS say— U 8 U 7 Yon know certainly that either four, or three, and ten lie with Y, and no more. Kor three and four arc certainly not both with li, or he would have returned his lowest. Neither four nor throe lie with X ; thcroforo, one of these cards lies with S, who has, therefore, led the beat of two. Y'ou can thus place every card, assumiug always that all are playing according to the customary rules for good play. B has cither the three or four left. 1' has ten, and either four or three. Z has the Ace, and is holding it back for some purpose con- nected with the strategy of his hand. Y'ou therefore play Knave thii-d in hand ; whereas, had you not attended to the fall of the eardr, you might have thought it a fair linesso — only ton ami Ace being against you, and the Aco probably in fourth hand — to [lass the eight, so as to make sure of taking tho last round in trumps. As it is, you know that, after your Knave has taken tho second round, your third lead of tho five will draw both tho Aco and ten, leaving you with tho long trumi>. A BiMPEH .IT Whist. — A correspondent, " Hazard," nsks how to di'termine the odds against a bumper at H'/ii.v(.' The problem i.'» a very difficult ono. in fact, it is )irnctically insoluble. Our correspondent remarks that there are nine ways of winning a rubber of two games, meaning, wo suppose, that each game may be won, oitlior by five or more points, alono ; by three or more points and two by honours ; or by ono jjoint or more and four by honouis; and therefore tho pair of games in 3x3 different ways. But, in reality, there are many more ways than three in which a game can be won, even if we only consider tho points obtained, and tho honours marked. And to determine tlip tiuo cliaiices we must consider more than this. Wo bIuiuM li.iv.- (u ilrlcrmino tho number of com- binations of hands l.y wli.li wiili tho best piny, or with good play on both sides, or witli iri...|.iiii(. pliiy met by bad play, or with good play met by atrocious liliiTuleriii^.', and so forth, a game might bo made in a single round j in how many ways it might bo made under correspondingly varying conditions in two rounds, in throo rounds, in four, and in five. The same would have to bo done for the second game. Tho numbers thus obtained would have to bo multiplied together, or rather tho number scpiared. Then tho total number of combinations for 'all cases of ono round, two rounds, Ac, for each game would have to be determined. The chance of a bumper would be tho ratio of tho former number to tho latter. Bat no ono could possibly work out tho problem in this way. — Editor. The Gr. Contents of Knowledge ^o. 33. FiOS. 1 PJI r OsUcry" 33 EnulUh Spositlo Ilcalth-Kcaorls. By II. the Pharaoh of the Oppre»8ion? By Amelia B. Kdwards. II.— Joseph's Placi- in Uislory The Amateur Electrician — Elec- tric Generators {Itluttrated) How to Get Stronc A HtudT of Minute Life. By Henry ■ ■•■ " F.K.Mri. nd Duty ;)8 | Our Chess Co Alfred Httviland . Homo Cures for Poisons 4^ MACA21NE OF SqiENCE^ PLAINLTY/ORDED -JEXACTLTBESCRIBED , ! LONDON: FBIDAY, JUNE 30, 1882. Contents op No. 35. »Aa». ■Was Ramescs II. the Pharaoh ot the Oppression? By Amelia B. Edwards. III.— The Pharaoh of Joseph 65 Honey Ants. By Grant Alien 66 How to Ride a Tricycle. By John Home Cures for Poisons .... The Amateur Electrician - trie Generators Electromania. By "W. Mattiei Williams .'. A Surgeon's Tools: Clean or Un Weather Chart for the Week 74 Star Map for July 73-78 CoBRBSPOXDSMCE ; Tobacco and Consumption— The Fever Tree,&c. 79 Answers to Correspondents 52 Oar Mathematical Column 83 Our Whist Column S4 Onr Chess Column 85 WAS RAMESES II. THE PHARAOH OF THE OPPRESSION? By Amelia B. Edwards. III.— THE PHARAOH OF JOSEPH. BUT, it will be asked, ■what was the name of this Pharaoh, and what place did he occupy in the suc- cession of Hykshos kings ] Tradition, represented by the Byzantine monk, George Syncellus before mentioned, and also by John of Antioch, of whose work only a few fragments are preserved (see Miiller : Fragmenta JiistoricorJivi f/racoriini, vol. iv., p. 555), assigns the name of Aphobis to the Pharaoh whose dream was intei-preted by Joseph. Now Aphobis, or Aphophis, is the Greek way of writing Apapi ; and Apapi was a name borne by at least two Hykshos rulers, one of whom belongs to the 15th and one to the 17th dynasty. Of the first Apapi nothing is known but his name. It is the second Apapi nnder whom Joseph is believed to have tlourished; and this Apapi — the Apapi of the 17th dynasty— was the last of the Hykshos kings. It was in his time that a tributary prince of Thebes, Rasekenen Ta-aken, raised the war of national independence wliich ended in the expulsion of the shepherds. Sphinxes and statues engraved with the name of Apapi have been found in the mounds of Sfm (the Zoan of the Bible) where the Hykshos est.ablished their capital ; and a succinct contem- porary account of the war of independence is found at El Kab, Upper Egypt, sculptured on the walls of the toml. of a certain naval officer named Aaiimes, whose father servetl on the legitimate side under Rasekenen Ta-aken, and who was himself distinguished for personal valour tliroughout the later campaigns of that same war, when the fortresses of Avaris and Sherohan were besieged and taken, and the Hykshos were driven from their la.st strongholds. In Apapi II., therefore, we are dealing with an historical personage ; and in all that relates to the war of liberation and the expulsion of the usurpers, we are dealing with historical facts. The Sphinxes of Apapi arc liuman- headed, and in their hard-featured, melancholy faces not only preserve the record of a singular and distinct Asiatic or Asiatic-Scythian type, but in all probability hand down to us tlie poi-trait of the king himself. The fortress-camp of Avaris (in Egyptian Ha-uar) exists to this day in the mounds of Tel Herr ; and as for Rasekenen Ta-aken, Prince of Thebes, and King Ahmes I., by whom Apapi was expelled and Avaris captured, their mummies were both found last summer in the famous hiding-plate at Dayr-el- Baharee, and are now on view in the Museum of Boolak. Historians are agreed in representing the war of libera- tion as a very long war, and Professor Maspero attributes to it a duration of more than 1 50 years. I venture, how- ever, to think that the hypothesis which makes Joseph the interpreter of Apapi's dream is incompatiljle with the hypothesis of so very long a war. 1 would even go so far as to suggest that Joseph must not only have risen to power under some earlier Hykshos king, but that the war did not, Ln all probaliijity, last longer than thirty years. Let us frst take the internal evidence of the Bible narrative. That narrative relates to the youth and prime of Joseph, and the scene is evidently laid in a time of profound peace. There is plenty in the land, and there is famme in the land, and people come from far and near to buy and sell ; but there is no hint of either internal or external strife. It is even said that Joseph, after he had bought up the land for Pharaoh, removed the people to cities " from one end of the borders of Egypt even to the other end thereof ; " a precautionary measure which, by the way, was pecu- liarly Egyptian, and which Barneses II. is especiallj- recorded to have taken in dealing with captives from the north and captives from the south, whom he transplanted in enormous gangs, from one extremity of the country to the other. But neither Rameses II. nor Joseph could have s'> transplanted large bodies of either citizens or captives, if the whole of Upper Egypt had been in arms. Seeing, .also, with what minuteness of detail the early biography of Joseph is given, it seems impossible that no mention should be made of a harassing and prolonged civil war, if such a war had at that time distracted the country. Besides, it is expressly stated that "Joseph was thirty years old when he stood before Pharaoh ; " and although the age at which ho is said to have died — namely, 110 years — was a typical phrase in use among the ancient Egyptians to express the ideal length of days, and is, there- fore, not perhaps to be accepted literally, yet it is certain that Joseph lived to be a very aged man ; so aged that he may well have flourished under two, or even under three. Pharaohs. Be this as it may, however, I do not think wc can be very far wrong if we place the promotion of Joseph under the predecessor of Apapi ; nor if we conclude that, Iiaving, as an old man, witnessed the beginning and greater part of the war of liberation, he died, was embalmed, and " put in a coflin in Egypt," towards the end of the reign of Apapi, the last Hykshos king. The immediate predecessor of Apapi is identified by Pr. Birch* with a cirtaiii Hykshos Pharaoh calknl Sut-aa peh- peh (or Sut-aa-peli ti) Nubti, whose name appears on a tablet discovered by the late Mariette Pasha in the ruins of SSn (the Zoan of the Hebrews, the Tanis ot the Greeks), where the Hykshos established their capital city. In this tablet, which was put up by a certain governor of the province who held office under Rameses II., it is recorded that the king ordered the tablet to bo made in honour of his ancestors, and that the governor came to Zain "on the 4th day of the month of :Mesori (the twelfth month of the year) of the lOOtli year of Sutraa-peh-peh Nubti, Son of the Sun." in order to be present at the festival of its installation. See " Records of the Part," toI. vi. p. 36. 66 KNOWLEDGE ♦ [Junk 30, 1882 The interest of this tablet," says Mariette Pasha, in his Vppendix to the Catalogue of the Boolak Museum, •• centi t« iu the date. Tliis dat<" is not Egyptian ; it is Egypto-Asiatio, as were tlie inhabitants of Tanis, Four hundred years before, a shepherd-king, tho Nubti of our tablet, had endowed the llykshos with a fixed calendar gs and appendages. All over the vaulted dome of the anthill, these little creatures were clustered in numbers, their yellow bodies pressed tight to the roof, while their big round stomachs hung down behind from the slender waist, perfect globes of translucent tissue, showing tho amlicr honey distinctly through the distended skin. They looked like largo wliite currants, or sweet- water grapes ; and as they were actually filled with grape- sugar, the resemblance was really quite as true inside as out. Wliere did the honey come from 1 That was the next question. Everybody knows that ants are very fond of sugar, and they often steal tho nectar in flowers which the plant has put there to entice tho fertilising bee. So much damage do they do in this way, that many plants have clothed their stalks with hairs, or sticky glands, on purpose, in order to prevent the ants from creeping up the stem and rifling the nectary. In other cases, however, plants actually lay by honey to allure the ants, when they have anything to gain from their visits, as in the case of those Central American acacias, mentioned by Mr. Belt, which have a nectar-gland on the leaf-stalk to attract certain bellicose ants, which so protect them from the ravages of their leaf- cutting congeners. Of course, everybody has heard, too, how our own species sucks honeydew from the little aphides, or plant-lice, which have often been described as antcowa But it is not in either of these ways that tho honey-ants get their sugar. Dr. McCook had a little trouble in settling this matter at first, for the honey ants are a nocturnal species, and he had to follow them through the thick scrub, lantern in hand ; still, he satisfactorily settled at last that they obtain the nectar from the galls on an oak, where it must simply be exuded as an accidental product of injury. The workers take it home with them, and give it to the honey- bearers, who swallow but do not digest it. They keep it in their crops ready for use, exactly as bees keep it in cells of the honeycomb. When the workers are hungry they caress a honey-bearer with their antennoc, whereupon she presses back a little of the nectar up her throat, and the workers sip it from her mouth. The honey-bearers, in short, have been converted into living honey-jars. _ They are thus passively useful to the community, for in this curiously-ordered commonwealth they also serve who only stand and wait How could such a strange result as this have been brought about? Dr. McCook, though not himself an avowjd evolutionist, has supplied us with facts which seem to sugf'est the proper answer to this dillicult question. He has shown that the rotunds (as he calls them) are not, in all probability, a separate; caste, but are merely certain specialised individuals taken at haphazard from the worker- major class. He saw himself in tho nests many worker- majors, which seemed at that moment actually in course of transformation into lioney-bearers. Now, it is easy enough to understand why these social insects should wish to store up food against emergencies. At all times, the qucson, tho youn" female ants, the males, and i\u: grubs or larviu are entirely dependent upon others for support Hence, alike among bees and ants, stores of food are habitually laid by, sometimes- in the form of honey in combs and bee-bread, as with the hive-bee; sometimes in the form of seeds and grains, as with tho harvesting ants. During the winter months or the rainy season, when food fails outdoors, there must be some reservoir at home to meet the demand of the starving community. Under such cir- cumstances, any trick of manner which tended to produce June 30, 1882.] ♦ KNOWLEDGE 67 a haLit of storing food would be highly useful to the nest as a whole ; and, taking nests as units in the struggle for existence, which they really are, those nests which possessed any such trick would survive in seasons when others might perish. So the tendency, once set up, would grow and be strengthened from generation to generation, those ants which stored most food being most likely to tide over bad times, and to hand on their own peculiarities to the other swarms or nests which took origin from them. A set of primitive ants, living upon the honey of the oak-galls, have no tendency to produce wax, like bees, because their habits with regard to their larvae do not lead them to make such cells at all. The eggs and grubs .simply lie about loose amongst the chambers of the ant- hill, instead of being confined in regular hexagonal cradles. Hence the bees' mode of honey-storing is practically im- possible for them : they have not the groundwork habit from which it might be developed. But the ants have a crop, or first stomach, in which they store their undigested food, before passing it into the gizzard, exactly as in fowls. When ants come back from feeding, whether on flowers, on aphides, or on galls, their crops are very much distended ; and they can bring back the food to their mouths from these distended crops, to supply the grubs and their other helpless dependents in the nest. If, therefore, some of the ants were largely to over-eat themselves, they would be able to feed an exceptionally large number of depen- dants. Dr. McCook observed that some very greedy workers, returning to the nest, fastened themselves upon the roof in the same position as the honey -bearers, and in fact seemed gradually to grow into rotunds. The other ants would soon learn that such lazy, overgrown creatures were the best to go to for food ; and, in time, these gorgers might easily become specialised into a honey-bearing set of insects. The workers would bring them honey, which they would store up and disgorge as needed for the benefit of the rest as a whole. If the honey passed into their gizzards and was digested, they would be a positive dead loss to the community, and so the tendency would soon be eliminated by natural selection, because the nests possessing such workers could not hold their own in bad times against neighbouring communities. But as only a very small quantity is ever digested — just as much as is necessary to keep up the sedentary life of such immovable fi.xtures — the eflect is about the same as if the honey were stored in cells of wax. The ants, in fact, utilise the only good vessel or utensil they have at their disposal, the flexible and extensible abdomen of their own comrades. The greatest difliculty is to understand how the workers first acquired the habit of feeding these lazy members to such repletion ; but as all ants " take toll " of one another, this is much less of a crux than it looks at first sight. A very greedy ant, which not only ate much itself while out foraging, but also took toll of all otliers in the nest, after it was too full to move about readily, would be in a fair •way to become a rotund. And as it would thus be per- forming a useful function for the rest, at the same time tliat it was gratifying its own epicurean tastes, the habit would soon become fixed and specialised, till at last we should get just such a regular and settled form of honey-storing as we see in this Colorado species. Indeed, another totally distinct type of ant in Australia has arrived at exactly the same device quite separately, as so often happens in nature under similar circumstances. Whatever benefits one creature under any given conditions will also benefit others whoso conditions are identical ; and thus we often get adaptive resemblances between plants and animals very widely re- niovetl from one another in genealogical order. HOW TO RIDE A TRICYCLE. By John Brownisg (Trtaturerof the London Trin/cU Club). T^HE greatest disadvantage the tricycle has to contend with is the supposition that anyone can ride it without learning. I have proved the reverse, to my own satisfaction, in the following simple manner: — I have driven a double tricycle with my wife by my side and fifty pounds of luggage beliind us for twenty miles without fatigue, while I have ridden with a strong man less than eight miles on the same machine without luggage and been tired out. Yet my wife, on the occasion to which I refer, did not drive, but had her feet on the foot-rests, while the gentleman, being a very powerful man, was, 1 feel certain, exerting twice the strength I was using myself. There seems to me but one possible explanation of this — that riders without practice press down both feet together, pressing one foot down a little harder only than the other, instead of lifting up one foot and pressing down the other at the same time. Again, tricycle riding brings muscles into action that are not used in walking, and these mtiscles require to be gradually strengthened by practice before either long rides or fast riding are attempted. Many persons having hired a machine, and driven it a few miles, have found it very hard work, and given up all idea of purchasing one. Beginners should restrict themselves for several weeks to riding from five to ten miles at a pace not exceeding six miles an hour. I know one case in which a gentleman bought a tricycle, and against advice rode it home about ten mUes. The next day he wrote to the agent and asked him to send for the machine and sell it for an}- price he could get for it. Another instance I was told of where a gentleman hired a tricycle in the north of London for a week, and paid for it, and started to ride to Portsmouth. In less than two hours he brought the machine back, and a-ked to return it and forfeit any amount of the payment he liad made the maker pleased, adding that he had had enough of it. Hills should never be attempted until the rider can ride well on the level. Considerable practice is required to ride hills without great fatigue. Time and strength are saved in the long run by dismounting as soon as the strain is felt to be at all severe. An exceptionally strong rider may soon succeed in riding up a tolerably steep hill, but he will waste strength which would have carried iiim at a greater pace or to a further distance if he had liusban.ied it by dis- mounting. After a few months' practice the rider will run up hills almost unconsciously which would ot first have taxed him severely. Next, as to riding down hill. Choose a machine with a break which is applied to both tlie driving wheels. When riding on the level or down a slight incline put on tlio break slowly, but firmly. If it acts efficiently it will bring the machine to a standstill without causing it to swerve to eitlier side. Should it swerve round the rider should not attempt to desceiul a steep hill on it until the fault has been corrected, under the penalty of being thrown out by its turning over. The swerving is caused by one break acting on one tiro more than the break on the other. Machines which drive both wheels by means of what is called a balance gearing from one cliain are not liable to this serious fault In descending a hill on a tricycle w ith a trustworthy break, the f.et should be taken ofl" the pedals and planted firmly on the foot-rests, as the body is steadier, and the macliine can be steered moiv accurately than when the legs are moving rapidly, and the legs are, of course, rested. KNOWLEDGE [June 30, 1882. The iiiacLiuc sliouki not bo steered to avoid loose stones wbt-u running down hill, the speed should be decreased, and the rider should go straight through them. A tricycle will turn in a much shorter space than a bicycle, but it should never be turned when running quickly. The speed should be reduced to about four or live miles an hour, and the rider should lean over in the direction towards which he wishes to turn. The rule of taking the feet oft' the pedals when riding down hill will not apply to tlie Humber Tricycle. That machine throws a great strain on the arms as soon as the feet are taken oil" the pedals. The feet are, with practice, unconsciously used in steering, and after a time an expert rider can steer this machine without holding the handles. Beginners will find it well not to pull hard at the handles of any tricycle continuously ; but to use them scarcely at all when riding down an incline, only moderately when on a level road ; and to reserve them principally for use when working on rising ground, when, from having Vicen only occasionally used, they will be a powerful assistance. Their constant use will be found very fatiguing. In all that I am saying I am supposing the rider wishes to travel as far as his strength wiJl allow him, at a pace of about seven or eight miles an hour. Should his only object be to ride at the top of his speed, he must almost stand on his pedals, lean well forward, and pull hard at the handles. A strong rider, with practice, can ride at the rate of t»velve miles an hour for two or three hours, and at the rate of ten miles an hour for four or (ive hours. The amateur champion, Mr. Lacy Hillier, has ridden fifty miles over an exceedingly hilly road in four hours, fourteen minutes. I am often asked to state the comparative speed of bicycles and tricycles. I consider the tricycle is about two miles an hour slower than the bicycle. The remark is fre- quently made that the tricycle is much harder work than the bicycle. I reply, not at the relative speeds I have named. The tricycle has an immense advantage over the bicycle in being capable of adjustment to the strength of the person who is going to use it A machine with driving-wheels 54 in. in diameter, geared level, would require a strong and practised rider to drive it up a moderate incline ; but by replacing the lower wheel, which carries the chain, with a wheel from an inch to two inches smaller, the machine can be made to run so lightly that it may be driven easily — of course at a slower pace — up moderate inclines by a lady, or even by a child. Tricycle riding is gaining ground more rapidly even than bicycling. The best makers of well-known machines cannot execute orders under about two months, and makers of one well-known Sociable (that is double tricycle) will not at prewnt accept orders to be executed in a stipulated time. Tlie cranks of double tricycles are made in two ways. In one construction the right foot of each driver rises and falls at the same time. In the other the right foot of one driver is half way up when the other is either up or down. This is called putting the crank on the quarter turn. The last arrangement is the best for hill-riding, but is not so con- venient or erticient generally, as it gives the appearance and sensation of two scullers in a boat taking strokes alter- nat«ly — a proceeding most ungraceful in appearance, and one by which strength is wasted. The advantages of tricycles over bicycles are numerous and evident They can l»e ridden at a slower pace than the bicycle, or stopped at any time, without dismounting, to admire a view, in.sj^ec-t a building, read the direction on a linger-post, or speak to a friend. They will carry almost any amount of luggage. A great many tricycles are now employed by the postmen in country ilistricts for carrying letters and parcels. Policemen and lamplighters are also using them. Tri- cycling brings more muscles into play than walking, and is a more exhilarating exercise. To the healthy and strong it is oven more exhilarating than horse-riding. Our greatest authority on health, Dr. B. W. Richardson, F.R.S., recommends stout people to adopt it, and says that a very stout person will find that he can ride six miles with less fatigue than he can walk one. I know many persons who have given up rowing after a short experience of trieyling, sajing that the rush down a breezy hillside is more exciting and exhilarating than a row on either river or sea. I consider that a tricycle-rider has almost as great an advantage over a walker as a rider in a railway train has over a rider in a coach. Where roads are fairly good, a tricyclist can cover six miles with less fatigue than a pedes- trian can travel three. It is probable that the rapid increase of tricycling will, before long, cause a great im- provement in our country roads. Were they made exceed- ingly good, ten miles an hour could be ridden on a geared- up or speeded tricycle (in which the wheels would turn round quicker than the cranks moved by the feet) easier than a pedestrian could walk four miles an hour. The rapid improvement being made in double tricycles is inducing many bicyclists to adopt Ihcm who have not been tempted by the single tricycle. The weight of a double tricycle is much less than that of two single tri- cycles, and they can be ridden by two good riders at as great a pace as a bicycle. The enjoyment of riding one of these machines with a friend, particularly with a lady- friend, must be tried before it can be fully appreciated. THOUGHT-READING. By the Editor. DICKENS describes another feat which the conjurer performed, which, were it not that the first can only be explained as a feat of n)ind-ruling, we might explain as a trick merely of legerdemain and quickness of vision. But, under the actual conditions, it seems to indi- cate powers of mind-reading far more surprising than any ever noticed in parlour experiments. The conjuror "had several common school-slates about a foot square. He took one of thfmi to a fieldoilicer from the camp, decori and what not, who sat about six from our scats, with a grave, saturnine friend next him. ' My General,' says he, ' will you write a name on this slate, after your friend has done sol Don't show it me.' The friend wrote a name, and the General wrote a name. The conjuror took the slate rapidly from the officer, threw it violently down on the ground with the written side to the floor, and asked the officer to put his foot on it and keep it there, which he did. The conjuror considered for about a minute, looking devilish hard at the General. 'My General,' says he, ' your friend wrote Dagobcrt upon the slate under your foot.' The friend admits it ' And you, my General, wrote Nicholas.' General admits it, and everybody laughs and applauds. ' My General, will you excuse me, if I change that name into a name expressive of the power of a , great nation, which, in happy alliance with the gallantry and spirit of France, will .shake that name to its centre ?' [This was in 1854.] 'Certainly, I will excuse it' ' My General, take up the slate, and read.' (General reads : ' Dacoijkkt, Victohia.' The first in his friend's writing ; the second in a new hand. I never saw anything in the least like this ; or at all approaching to June 30, 1882.] • KNOV^^LEDGE the absolute certainty, the familiarity, quickness, absence of all machinery, and actual face-to-face, hand-to-hand fairness between the conjuror and the audience with which it was done." It is clear that in this feat there was legerdemain, and (in a sense) machinery, too. Several common school slates were brought in, but one slate only was used. We may be sure this, however it resembled the others, was not, like them, a common school slate ; and that the name, Victoria, was already written on it under the surface which was pre- pared to receive whatever name the General's friend might write. We might also explain the conjuror's knowledge of what the General and his friend had written, by tlie wonderful quickness and keenness of sight which conjurors obtain with constant practice. That some can tell what name is being written, by watching the movements of the pencil-end remote from the slate or paper, is certain. I am disposed, however, to consider this a case of mind- reading, after the much more wonderful case cited before, which can only be explained as an instance of mind-ruling. In the following cases it seems doubtful whether mind- reading or mind-guiding were in question. Prof. Barrett is referring to trials made with the children and a young servant-girl of the Rev. Mr. G, of whose personal integrity he was convinced (though, of course, this statement re- specting a person unnamed must be taken only for what it is worth, that is, as an expression of opinion). " Having selected at random one child, whom we desired to leave the room and wait at some distance, we would choose a card from a pack, or write on paper a number or a name which occurred to us at the moment. Before leav- ing the room the child had been informed of the general nature of the test we intended to select, as 'this will be a card,' or ' this will be a name.' On reentering she stood — sometimes turned by us with her face to the wall, often with her eyes directed towards the ground, and usually close to us, and remote from lier family — for a period of silence varying from a few seconds to a minute, till she called out to us some number, card, or whatever it might be. . . . The first attempt was to state, without searching, the hiding-place of some small object, the place having been chosen by ourselves, with the full range of the house, and then communicated to the other members of the family. This was cflected in one case only out of four. The next attempt was to give tlie name of some familiar object agreed on in the child's absence, as 'sponge,' 'pepper-caster,' ifcc. This was successful on a first trial in six cases out of fourteen. We then chose a card from a fuU pack in the child's absence, and called upon her to name it on her return. This was successful at once in six cases out of thirteen A harder trial was now introduced. Tlie maidservant liaving left the room, one of us wrote down the name 'Michael Davitt,' showed it round, and then put the paper in his pocket. The door was now opened, and the girl recalled from tlie end of the passage. She stood close to tlu; door amid absolute silence, and with her eyes on the ground — all of us meanwhile fixing our attention on the appointed name^and gave after a few seconds the name ' Michael,' and then almost immediately 'Davitt' To avoid any association of ideas, we then chose imaginary names, made up by ourselves at the moment, as ' Samuel Morris,' ' John Thomas Parker,' ' Pha'be Wilson.' The names were given correctly in toto, at the first trial in five cases out of ten. Three cases were complete failures, and in two the names given bore a strong resemblance to those s<'loctcd by us, 'Jacob Williams,' being given as 'Jacob Wild,' and ' Emily Walker,' as ' 'Enry Walker.' It was now getting late, anil both we and the younger children were very tired ; and four concluding attempts to guess the name of a town in England were all failures, though one of us had previously obtained remarkable success in this very experiment." It appears to me that the failures in these and other cases yet to be cited, arc as important a part of the evidence in favour of mind-reading or mind-ruling, as the successes. For they tend to show that there was no general system of deception by which the members of the family who had been present when the names were selected informed the children by .signals previously agreed upon. However, as it will be obvious that there can be no abso- lute certainty on this point in cases in which any members of the family knew what was selected, we proceed to con- sider cases in which only the committee of investigation knew the words or things chosen. (To be continued.) HOW TO GET STRONG. WE have received, through the Editor, a great numbti of communications, with which we propose to deal consecutively before passing to the consideration of othc exercises for the expansion and development of tin chest. Several correspondents ask about the mstruracnt called an inspirometer, which is mentioned in a quotation from an American work. We must trust to American readers to answer this question ; for we have not ourselves seen or used this instrument. The breathing test, used at various places of amusement, though on a diflerent principle, serve s the same purpose when properly used. A'ery few people seem to know how to use this instrument The Editor writes to us as follows, very much to the point, en this subject : — " Have you ever noticed what very poor records most persons make with the breathing apparatus, compared with what they can make when they go to work properly ? You will see a well built man, standing some six feet in his stockings, who, advancing to the instrument, will begin to blow, watching the index with a look as if he would send it round to 100 at least, yet will barely mark 200 ; yet there is nothing wrong with the big fellow's lungs, as from such a record for such a height one might judge. Tell him how to do it, and he will send the index well over 300. I have watched a score of men who ought to reach 2fi0, averaging not more than 150. Then I have taken the tube, and though below the middle height, and too fleshy for full breathing, have sent the index on beyond 200 to 250, to ;!U0 (till people began to ask whether I >>as breath- ing out of my boots), and em to 340 or SoO^the greatest I have reached being 353. Then one or two have a.'^keil me, apart, how the thing was done, and I have explained that before ex-spiring, the breath is to be drawn in till you can draw in no more, and every atom of air so drawn in is to be let out steadily through the tube, none e'scnpiiig beforehand. I have then seen a man who had just., with utmost eflbrts, readied 180, go easily above 300." Speaking of fleshiness, it should be added to the usual instructions respeH-ting the use of the breathing apparatus, that any addition to the weight beyond that due to fair condition, is certain to aflect the record with the breathing apparatus. Several correspondents ask our opinion of various exer- cises, as rowing, riding, walking, tricycling, boxing, cricket, itc. It will probably sound paradoxical, after the stress we have laid on the necessity for exercise, to say that we consider each one of these exercises, (is pur^tied ftf 70 • KNOWLEDGE ♦ [June 30, 1882. ipr<'ialUU, undeniably bad for the development of a well- proportioned and thoroughly healthy frame. Take, for instance, any first-class eleven at cricket ; select, if you please, an eleven such as the Australian, in which all-round aptitude is a characteristic feature, and you will invariably tiud so large a proportion of ill shaped men as to show that thoroughly well-built cricketers owe their goodly proportions to exercises outside cricket Despite the running involved in tlie game, four cricketers out of five have badly-d'^'Iopcd chests. One would say a good bat should have _'ooiI shoulders, but that batting does not tend to improve tlu' shoulders is shown by two, at least, of the finest Australian bats. Take rowing, again. Unless a rowing wan does other work especially int<'nded to correct the defect, he has invariably poor arms above the elbow, a marked inferiority in the development of the chest as com- pared with the back, and he generally has round shoulders and a forward hang of the liead and neck. Boxing is better, but it cannot be pursued with advantage as the chief exercise a man or boy takes, and it is entirely unsait«d to girls and women (for whom we write, by-the- way, quite as much as for boys and men, though for girls our calf-skin dumb-bo.xer may not be the best of all chest- oj)ening exercises). In answer to many inquiries, we note that Mr. lUackie's work, "How to Get Strong," is published by Harper i Brothers, New York. We do not know the price. Much of its contents are specially intended for American readers. Maclaren's little book (not on Dumb- l>ells, as some readers seem to suppose, but on Training), is published by ilessrs. Macmillan. Other correspondents ask us what weight dumb-bells ■should be for 'p^i^o'is of given height and weight. Every one who uses dumb-bells should have them of different weights for different exercises. There are some chest exercises for dumb-bells which would tax the strength too much if the dumb bells weighed more than two pounds "•ach (these would be wooden), while for exercises in putting Tip weight, the dumb-bell.s should weigh from six pounds •■ach to ten pounds cacli. It is better to have them too light than too heavy, unless the person using them is going in for athletic honours ; but we are not writing for sucli persons. Clubs have several usea for which dumbbells are not available, especially for exercise in wrist play. We are asked by some of what shape they should be, and where to be purchased. We thought every one knew the ordinary .shapes of Indian clubs, — straight handle, with a knob to prevent the club slipping out of the hand and spindle- shaped heavier part, in plain or polished wood. Any wood- turner would make a pair for a few shillings, and would require no other instructions but " Indian clubs of such and aush weight eaclj." The clubs ought not to be heavy. Five pound clu1(S (that is ten pounds weight the pair) will serve men strong enough to u-ielff clubs of twice or thrice their weight ; in fact, many flourish about heavy clubs and sway heavy dum1>^b(ll3 with apparent ease, but really to their own detriment ; for to support the strain of heavy clubs or dumbU-lis, tlie chest assumes a constricted attitude, just as it does in very hard rowing, and in several other exercises which men pursue under the impression that they are im- proving their development. The effect of constant hard work in special directions may best be judged l>y noticing porters, coal-heavers, and the like away from their ordinary employment They do their work so well, that one would say they were very powerful men, and so in a way they are. But they cannot walk freely ; nay, some of them can scarcely stand upright (To be eonlinwd.) A HOME CURES FOR POISONS. ANTIMONY. NTIMONY and its compounds would not bo dan- gerous were it not for the too prevalent opinion that they may be used in all cases, safely, as enietics. Antimony itself cannot be used in this way until it has been so modified by chemical admixture as to be capable of decom- position by the fluids of the body. For this purpose tartarised antimony, in the form commonly known as tartar emetic (the doubh; tartrate of potash and antimony) is usually employed ; and most cases of antimonial poison- ing have arisen from the administration of tartar emetic in large doses. The employment of this substance to detect children or servants who have taken forbidden articles of food has led to some very sad cases of poisoning. The practice cannot be too strongly reprehended. Tartar emetic has also been used, as foolishly, to cure confirmed drunkards of their bad habit, by causing sickness. The latest case in which the use of antimony as a poison, with criminal intent, was suspected, was the so-called Balham tragedy. The case was very diflicult to understand, but very instructive. It may be remembered that Mr. Bravo had bought a quantity of tartar emetic for the purpose of dosing Mrs. Bravo's wine, so that she might be cured, if possible, of her tendency to drink it in undue quantities. After a quarrel he had gone to his room, and soon after began to suffer severely from what eventually proved to be the effects of antimonial poisoning. He lingered in great pain for two or three days, and during that time nothing transpired to suggest that ho had been wilfully poisoned. After his death the body was examined, and it was unmistakably shown that death was caused by anti- monial poisoning. Mrs. Bravo was suspected of having murdered her husband, the idea being that a medical friend of hers had suggested to her the use of tartar emetic to poison Mr. Bravo. The whole theory of those who suspected Mrs. Bravo was absurd on the face of it, and, proliably, but for the horror which the supposed crime excited, the case would have been quickly closed ; but it was continued until the cruelty of the cross-examination to which Mrs. Bravo was subjected excited the pity of many who had had very little sympathy for her at the outset But the difljculty was to undtTstand how, in reality, the poison had been administered or taken. Mr. Bravo was well acquainted with the general proper ties of tartar emetic, and knew that in large doses the substance is poisonous. He could hardly have taken it by accident, or have taken more than a suflicient emetic dose, if he had proposed to use it in that way medicinally. The only theory which at all corresponded with the evidence was one wliich illustrates one of the characteristic proper- of this substance. I\Ir. Bravo had threatened to commit suicide, and had bought laudanum with tlu; avowed purpose of using it to kill himself. Persons who talk in this way very seldom do commit suicide; but it seems likely that after the quarrel referred to above, in the course of which he had repeated the threat, Mr. Bravo did take a poisonous dose of laudanum,- — trusting, we believe, to the tartar emetic in his possession as a safe and sure emetic by wliich to get rid of the laudanum, when it had served his purpose. But it so happens that while tartar emetic is very ceitain in its emetic action in nearly every case (being surpassed only in this respect by sulphate of zinc), it should never be taken in cases of narcotic poisoning, for in large doses tartar emetic is itself a poison unless the stomach quickly rejects it, and narcotic poisons so diminish the sensibility of the Junk 30, 1882.] KNO^A^LEDGE 71 stomach that it will retain under their action what, under other conditions, it would immediately reject Any one unaware of this, who had taken a dose of tartar emetic to cause vomiting after a narcotic had Lcen swallowed in poisonous or almost poisonous quantity, would 1)6 apt to repeat the dose, especially if ignorant of the quantitative poisonous properties of antimony. This, in all probability, was what Mr. Bravo did, until he had taken a poisonous amount of that substance by which he had hoped to get rid of the laudanum he had taken in excess. It was a noteworthy feature of the case that even when his anguish was at its greatest, he would not take laudanum for its relief. Be this theory correct or not (for our own part, we have no doubt of its correctness, for the simple reason that every other is in some one or other respect absurdly incon- sistent with the known facts of the case), it is well to know tliat tartar emetic is not suitable in cases of poisoning, though very proper, under medical advice, in other cases where an emetic is required. REMEDIES. When tartar emetic has been taken in poisonous amount, and vomiting does not follow, it must be excited until, if possible, all the poison has been rejected. Copious draughts of tepid water, tickling the back of the threat, and other such methods of producing vomiting may be employed. If, however, the poison cannot be got rid of in this way, a decoction of tincture of quinine may be given with advantage, for tartarised antimony is decomposed by nearly all bitter or astringent vegetables which contain tannin, producing an inert tannate of the protoxide of anti- mony (which is the active base of tartar emetic and James's Powder). Should no quinine be at hand, a strong infusion of black tea should be administered, pending the arrival of a medical man. THE AMATEUR ELECTRICIAN. ELECTRIC GEXEEATOES (continued). T"f 'E will now leave our magneto machine in the hands >* of our readers for a time. Possibly their own ingenuity may suggest one or two moditications. One that will reward the extra lal)Our and care involved is, winding the armature with two wires side by side sLmultaneouslj-, so that there will be four ends to deal with. By a simple contrivance the two coils may then be used at pleasure for intensity or quantity — that is to say, we may join them up so as to become one continuous coil, or we may connect the two internal ends together, likewise the two external ends. This latter course is practically doubling tlie size of the wire. The first arrangement would produce comparatively a current of high electro-motive force and small quantity, the second a current of low electro-motive force but large quantity. The next step that we may notice in apparatus of this kind is the introduction of electro-magnets in place of the ordinary steel magnets. These may consist of broad, Hat pieces of iron, like those in the Siemens or Brush dynamo machines (that is to say, the width e.xtendiiig the whole length of the pole-pieces) ; or of a series of ii-on rods enveloped with wire, as in the Weston m.ichine. Doubt- less, but few have seen this machine, but they will not go far wrong if they adopt the flat form, winding the iron ■with No. 18 or 'JO cotton-covered wire. Wilde is credited with introducing this form of machine. He used a small machine with permanent magnets to produce the current for magnetising the electro-magnet, and thus obtained in the armature actuated by this electro-magnet a very con- siderable current A small battery will serve the same purpose. The smaller machine or battery is generally known as an "Exciter." Its function is apparent It must be remembered that the polarity of the electro- magnets must be on the same principle as that which applies to the use of permanent magnets ; that is to say, the wire must be wound so as to induce north magnetism in one pole-piece and south in the other. It will be ad- visable to use four flat plates 4 in. by, say, C in., and \ in. thick, joining the pairs of free or external ends together by means of iron plates. The next discovery was one of vital importance. Those who have had any experience with electro-magnets, even on so small a scale as are used in telegraph instruments, will be aware that, however soft a piece of iron may be, it is almost certain to retain, for a greater or less time, a small amount of magnetism. This is called remanent, or residual magnetism, and Siemens and Wheatstone (simul- taneously but separately) found it sufficiently strong to enable them, by an ingenious arrangement, to dispense with the exciting current It is easily accomplished by the amateur. Join one of the brushes to one of the electro- naagnets (or field magnets), allowing the current to pass thence through the other magnet, and out to one of the terminals. The other brush is connected to the other ter- minal as usuaL What takes place is this : — First, there is a small amount of magnetism in the field magnets ; this induces in the armature a small current, which, being made to pass through the field magnet increases the inducing effect The increased armature current also passes through the field magnet, and so on and on, continually increasing until a very powerful current is obtained. This brings us to the end of our descriptions of simple forms of generatoi-s. Before we can go any farther, we must devote three, or perhaps four, articles to a brief account of the various methods of measuring electric currents, and of the units adopted in so measuring, never forgetting, however, that we are writing for amateurs. The Telephone i.v Fbaxce. — M. Cochcry, tlio French Ministcr of Posts and Telegraphs, has asked the Cliamber for a grant ot :i50,000 f. to enable him to establish a State telephonic servico between certain towns in France. Ax Electric Tramway. — The Portrush and Bushnols Electric Tramway, near Belfast, the first that has been constrnctcd in U><" United Kingdom, will be opened in the first week in August. Tho ceremony will probably be i)erformo«l by the Lord-Lieutenant. IXTERXATIONAL TELEGRAPH ST.vn.sTics. — According to statistics recently issued, the length of w^ires in the various countries is o» follows :— Germany, lo'J.UlO miles ; Russia, 134,465 miles: Franc*. 125,265 miles; Great Britain, 121,720 miles; .Austria-Hungary, 89,960 miles; Italy, 53,692 miles; Sweden and Norway, 2»»,445 miles ; Belgium, 16,345 miles, and Switierland, 10,010 miles. Tho total numbers of messages sent during the fmst venr are riasfed an follows :— England, 29,S20,4-I5: tVance, 19.882,»a8; Germany. 16,312,457; Austria-LIungarv, S.721t,321 ; Russia, 7,2!»S,422 ; Italy, 6,511,407 ; Uolland, 3,100,230 ; and Sweden and Xorwjiy, 2,02»,h06. The following should have forme*! part of the first paragraph on p. 63 : — The conclusions arriveiluied by one horse-power of current, is as follows : — {\.) At 16r.indles : Kdison, 265; Swan, 24; Ijine-Fox, 23 5 ; and Maxim, 20' » (U.) At 32 candles: Edison, 41-5: Lane-Fox, 37 4 ; Swan, 35 5 : and Maxim. 32 4. To doable the light given by these lamps the cnrrcnt-cnrrgy was increased, for the Maxim and Ijine-Fox lamps, 26 per cent : for the Edison lamp, 28 per cent. : and for the Sw:in lamp. 37 p«T cent. KNOWLEDGE • [June 30, 1882. ELECTROMANIA. BV W. IIATTIEU WlLLUMS. A HISTORY of electricity, in order to bo complete, must include two dUtinct and very different subjects : the history of olec- uioal gciouce, and a lu^tory of electrical exaggerations and delusions. The progress of the first has been followed by a crop of the second from the time when Kleist, Mnschenbroek, and Cunens endeavoured to bottle the supposed fluid, and in the course of these attempts stumbled upon the " Leyden Jar." Ur. Licborkuhn, of Berlin, describes the startling results which he obtained, or imagined, " when a nail or a piece of brass wire is put into a small apothecary's phial and electrified." lie says that •■ if, while It is electrifying, 1 put my finger or a piece of gold which I hold in my hand to the nail, I receive a sliock which stuns my arms and shoulders." At abont the same date (the middle of the last century), Muscheubroek stated, iu a letter to Keaumnr, that, on taking a shock from a thin glass bowl, " ho felt himself struck ia his arms, shoulders, and breast, so that he lost his breath, and was two days before ho recovered from the effects of the blow and the terror"; and that he "would not take a second shock for the kingdom of France." From the description of the apparatus, it is evident that this dreadful shock was no stronger than many of us h."\ve taken scores of times for fun, and have given to our school- fellows when we became the proud possessors of our first electrical machine. Conjurors, mountebanks, itinerant quacks, and other adventurers operated throughout Europe, and were found at every country fair and Jite displaying the wonders of the invisible agent by giving shocks and professing to cure all imaginable ailments. Then came the discoveries of Galvani and Volta, followed by the demonstrations of Galvani's nephew Aldini, whereby dead animals Wt-re nmdu to display the movements of life, not only by the eloc- tr'clty of the voltaic pile, but, as Aldini especially showed, by a transfer of the mysterious agency from one animal to another. According to his experiments (that seem to be forgotten by modern electricians) the galvanometer of the period, a prepared frog, could be made to kick by connecting its nerve and muscle with muiclo and nerve of a recently killed ox, with or without molallic intervention. Thus arose the dogma which still survives in the advertisements of electrical quacks, that " electricity is life," and the possibility of reviring the dead was believed by manj-. Executed criminals were in active demand ; their bodies were expeditiously transferred from the gallows or scaffold to the operating table, and their dead limbs were made to struggle and plunge, their eyeballs to roll, and th'-'ir features to perpetrate the most horrible contortions by con- noi;ting nerves with one pole, and muscles with the opposite polo of a battery. The heart was made to beat, and many men of eminence sup- posed that if this could be combined with artificial respiration, and kejit njp for awhile, the victim of the hangman might bo restored, pr .vidid the neck was not broken. Curious tales were loudly wh tpfred concerning gentle hangings and strange doings at Dr. Brookes's, in Leicester-square, and at the Uunterian Museum, in Windmill-street, now nourishing as " The Cafe do I'fitoilo." When a child, I lived about midway between these celebrated schools of practical anatomy, and well remember the tales of horror that were recounted concerning them. When Bishop and Williams (no rela- tion to the writer) wero hanged for burking, i.e., murdering people in order to provide "subjects" for dissection, their bodies wero sent to Windmill-street, and the popular notion was that, being old and faithful servants of the doctors, they were galvanised to life, and again set up in their old business. It is amunlng to read some of the treatises on medical galvanism that were publiihed at about this period, and contrast their positive statements of cures effected and results anticipated with the posi- tion now attained by electricity as a curative agent. Tlicn came the brilliant discoveries of Faraday, Ampere, Ac, dommitrating the relations between electricity and magnetism, and immediately following them a multitude of patents for electro- motors, and wild dreams of superseding steam-engines by magneto- electric machinery. The following, which I copy from 77ie Penny Mechanic, of June 10, 1 '•■37, is curious, and very in.structivo to those who think of investing !• any of the electric power companies of to-day: — "Mr. Thomas Mr.v<-nport, a Vermont blacksmith, has discovered a mode of ....'.;„,, mngnctic and electro-magnetic power, which wo have ■ Jtid for believing will be of immense imi>orlancc to the This announcement is followed by reference to Professor ' _ .•/« Ameiiran Journal of Science and the Aria, for April, l-.j7, and extracts from American papers, of which the following is a 8p»-ciinen :— " 1. We saw a small cylindrical battery, about nine inches iu length, throe or four in diameter, produce a magnetic power of about 800 lb., and which, therefore, we could not move with our titmost strength. 2. Wo saw a small whool, five-and- a-half inches in diameter, performing more than 600 revolutions in a minute, and lift a weight of 2-1 lb. one foot jier minute, from the power of a battery of still smaller dimousions. 8. Wo saw a model of a locomotive engine tmvelling on a circular railroad with immense velocity, and rapidly ascending an inclined plane of far greater elevation than any hitherto ascended by steam-power. And these and various other experiments which wo saw, convinced us of the truth of the opinion expressed by Professors ,Sillin\an, Keuwick, and others, that tho power of maohinory may bo increased from this source beyond any assignable limit. It is computed by these learned men that a circular galvanic battery about 3 ft. in diameter, with magnets of a proportionable surface, would jiroduco at least a hundred-horse power ; and therefore that two such batteries would be sutficiont to propel ships of tho largest class across tho Atlantic. The only materials required to generate and continue this power for such a voyage would be a few thin shoots of copper and zinc, and a few gallons of mineral water." The Faure Accumulator is but a very weak affair compared with this, Sir William Thompson notwithstanding. To render tho data of the above fully appreciable, I may note that three months later tho magazine from which it is quoted was illustrated with a picture of the London and Birmingham Railway Station displaying a fiist- class passenger with a boi seat on tlio roof of the carriage, and followed by an account of tho trip to Boxmoor, tho first instal- ment of tho London and North-Wcstorn Ilaihvay. It tolls us that, " tVo time of starting having arrived, tho doors of tho carriages are closed, and, by the assistance of tho conductors, tho train is moved on a short distance towards tho first bridge, where it is mot by an engine, which conducts it up the inclined plane as far as Chalk Farm. Between tho canal and this spot stands tho station- house for the engines ; here, also, are fixed tho engines which aro to be employed in drawing the carriages up tho inclined plane from Euslon-square, by a rope upwards of a mile in length, the cost of which was upwards of £400." After describing the next change of engines, iu the same matter of course way as tho changing of stage-coach horses, tho narrative proceeds to say that "entering tho tunnel from broad daylight to perfect darkness has an ex- ceedingly novel effect." I make those paroUel quotations for the benefit of those who imagine that electricity is making such vastly greater strides than other sources of power. I well remember making this journey to Boxmoor, and four or five years later travelling on a circular electro-magnetic railway. Comiiaring that electric railway with those now exhibiting, and comparing the Boxmoor trip with the present work of the London and North-Western Railway, I have no hesitation in affirming that the rate of progress in electro- locomotion during tho last forty years has boon far smaller than that of steam. Tho leading fallacy which is urging tho electro-maniacs of tho present time to their ruinous investments is tho idea that electro- motors are novelties, and that electric-lighting is in its infancy; while gas-lighting is regarded as an old, or mature middle-aged Lnsiness, and therefore we are to expect a marvellous growth of tho infant and no further progress of the adult. These excited speculators do not appear to bo aware of the fact that electric-lighting is older than gas-lighting ; that Sir Humphry Davy exhibited the electric light in Alboniarlo-strcet, while London was still dimly lighted by oil-lamps, and long before gas-lighting was attempted anywhere. The lamp used by Sir Humphry Davy at the Royal Institution, at the beginning of tho present century, was an arrangement of two carbon pencils, botwoon which was formed the " electric arc " by tho intensely- vivid incandosccnco and combustion of tho particles of carbon passing between the solid carbon electrodes. The light exhibited by Davy was incomparably more brilliant than anything that has been lately shown either in London, or Paris, or at Sydenham. Uis arc was four intliea in U-nylh, the carbon pencils wero four inches apart, and a broad, dazzling arch of light bridged the whole space between. The modern arc lights are but pigmies, mere specs, compared with this ; a leap of J or J inch constituting their maximum achievement. Comparing tho actual progress of gas and electric lighting, the gas has achieved by far the greater strides ; and this is tho case even when wo compare very recent progress. The improvements connected with gas-making have been steadily progressive ; scarcely a year has passed from the date of Murdoch's efforts to the present time, without some or many decided steps having been made. Tho progress of electric-lighting has been a scries of spasmodic leaps, backward as well as forward. As an example of stopping backward, I may refer to what the newspapers have described as tho "discoveries" of Mr. Edison, or the use of an incandescent wire, or stick, or Hhcct of platinum, or JONE 30, 1882.] KNOWLEDGE 73 platino-iridium ; or a thread of carbon, of which the " Swan " and other modem lights are rival modifications. As far back as 1S4(J I was engaged in making apparatus and experiments for the purpose of turning to practical account " King's patent electric light," the actual inventor of which was a young American, named Starr, who died in 1817, when about 25 years of age, a victim of overwork and disappointment iu his efforts to per- fect this invention and a magneto-electric machine, intended to supply the power in accordance with some of the " latest improve- ments" of 1881 and 1882. I had a share in this venture, and was very enthusiastic until after I had become practically acquainted with the subject. We had no difficulty in obtaining a splendid and perfectly steady light, better than any that are shown at the Crystal Palace. We used platinum, and alloys of platinum and iridium, abandoned them as Edison did more than thirt_v years later, and then tried a multitude of forms of carbon, includnig that which constitutes the last " discovery" of Mr. Edison, viz., burnt cane. Starr tried this on theoretical grounds, because cane being coated witli silica, he predicted that by charring it we should obtain a more compact stick or tliread, as the fusion of the silica would hold the carbon particles together. He finally abandoned this and all the rest in favotir of the hard deposit of carbon which lines the inside of gas- retorts, some specimens of which we found to be so hard that we requii-ed a lapidary's wheel to cut them into the thin sticks. Our final wick was a piece of this of square section, and about ^ of an inch across each way. It was mounted between two forceps — one holding each end, and thus leaving a clear half-inch between. The forceps were soldered to platinum wires, one of which passed upwards through the top of the barometer tulje, expanded into a lamp glass at its upper part. This wire was sealed to the glass as it passed through. The lower wire passed down the middle of the tube. The tube was filled with mercury and inverted over a cup of mercury. Being 30 in. long up to the bottom of the expanded portion, or lamj) globe, the mercury fell below this and left a Torri- cellian vacuum there. One pole of the battery, or dj-namo-macbine, ■was connected with the mercury in the cup, and the other with the upper wire. The stick of carbon glowed brilliantly, and with perfect steadiness. I subsequently exhibited this apparatus in the Town-hall of Bir- mingham, and many times at the Midland Institute. The only scientific difficulty connected with this arrangement was that duo to a slight volatilisation of the carbon, and its deposition as a bro^^^l film upon the lamp glass ; but this difficulty is not insuperable. A SURGEON'S TOOLS— CLEAN OR UNCLEAN? I HAVE told you one story out of our shop. Here is a second, true as the first, quite. The great master of British surgery, Sir Rusty Poyntz, and the smaller (I 'm not going, sir, to say smallest), which was your humble servant, met in consultation over a very sad and touching case. It was that of a young Eton lad, a fellow of keen eye, deft hands, and extra bright brains. His grand family house in a huge Belgravian Sfiuare was but a golden cage for that handsome, sweet- voiced skylark ; and, lark-Iikc, ho pressed his little heart against the golden bars — now singing, now sighing for the blue air, the Hashing rivers, the shout of the cricketers, the hum of the nine liundred — save one — this one ! It was a case of abdominal dropsy j and that were a hard, a hardest, heart which did not ache when the bedclothes were put aside, and the great, wax-like, tumid trunk disclosed to view, full to distension. It was to be tapped. As we went up the grand stairway. Sir llusty Poyntz opened his pocket-case of tools, and picked out one adapted for that operation. Mr. Smaller asked to look at it — previous experience having taught him that Sir R. P.'s tools wanted a little looking to. Sure enough, it was so now. The tool is called a trochai-. and consists of a split tube, the canula fitting over a piecing, triangular, tapering, and pointed end. Tho tube is slijiped down until it falls with a spring click into a groove, thus keeping the edge of tho tube under cover of the shoulder of tho stem, as the instrument is thrust into the body. This done, the stem is withdrawn, leaving the canula beliind to form a conduit, through which tho imprisoned licjuid of the , a gale ; >j > , a violent gale ; 0 signifies calm. Tho state of the sea is noted in capita) letters. The • denotes the various stations. The hour for which each chart is drawn is C p.m. Tt is ftated tljat within tho last few months a representative of the Chicago, Slilwankce, and St. Paul liailway has purchased in England about 20,000;. worth of machinery for the new carriage shops of the company. Some old bricks having been observed to affect the compass- needle by Ucrr Kepner, at Salzbnrg, in the Tyrol, ho then had two bricks made from each of eight varieties of clay in the neighbour- hood, one brick in each case being baked. Tho unbaked bricks did not affect the needle, but seven of the eight baked bricks proved polarly magnetic. Some further experiments have been made by Hcrren Kell nnd Trientl. Particles of X)Owder of tho magnetic bricks adhered to a steel magnet. Breunerite. mica-slate, argilla- ceous iron-garnet, chlorite, and hornblende were, before heating, anmagnetir, but intense heating produced a magnetic polarity, the axis of which seemed to bo perpendicular to the plane of stratification. In a recent lectnro on some of tho dangerous properties of dusts. Professor Abel, F.R.S., said that many experiments were tried with sensitive coal-dust from 8eaham and other collieries for tho purpose of asrertalning whether results could be obtained support- ing the view that coul-dnst, in the complete absence of fire-damp, ia susceptible of originating explosions and of carrj-ing them on indefinitely, as suggested by some observers; but, although decided eridencc was obtained that coal-dnst, when thickly suspended in the air, will be inflamed in the immediate vicinity of a largo body of flame projected into it, and will sometimes carry on tho flamo to some small extent, no experimental results furnished by these experiments warranted the conclusion that a coal-mine explosion could bo originated and curried on to any considerable distance ii> the complete absence of fire-damp. Some experiments made in a large military gallery at Chatham showed that tho flame of ai blown-out shot of IJ lb. or 2 lb. of powder miglit extend to a maximum distance of 20 ft., while in a very narrow gallery, similar to a drift-way in a mine, tho flame from corresponding charges' extended to a maximum distance of 3.5 ft. These distances aro considerably inferior to those which flame from blown-out shots ha» been known to extend, with destructive results, in coal-mines, and there appears no doubt that, in tho latter cases, of which tho- lecturer gave examples, tho flame was enlarged and prolonged by tho dust raised by tho concussion of tho explosion. But in th» presence of only very small quantities of fire-damp, dust may establish and i)ropagrfte violent explosions; and that, in tho case- of a fire-damp explosion, tho dust not only, in most instances, greatly aggravates tho burning action and increases tho quantity- of after-damp, but that it may also, by being raised and swept along by the Ijinst of an explosion, carry tho fire into workings where no fire-damp exists, and thus add considerably to the mag- nitude of the disaster. KNOWLEDGE, Jvnf 30, 1882.J OiR Stak Map. —The circular boundary of the map represeats the horizon. The map bhows also the position of the Equator and of that portion of the Zodiac uow mo>t favourably situated for observation. The names of ninety-nine stars of the first three magnitudes are given lielow. On June 30, at 1030 p.m. On July 3, at 1015 p.m. On July 7, at 10- 0 p.m. On July 11, at 9ir) p.m. On July 14, at 9:50 p.m. On July IH, at 9.1". p.m. On July •2-2, at 9- 0 p.m. ARABIC NAMES OF STARS. The following table exhibits the names of all the stars of the first three magnitudis whose names are in common use : — a Aiidromedas ... ... Alphcralz ... Mirach, itizur ... Ahnach o Aqnarii ... tiiidnlmAik J ... HaduUnnd. ... Skat a Aqoilas ... Altair fJ ... Al„hain ... Taraze/or,.> a Hvilra ... Alphnrd, I'or Uydm a Leonis ... Ke.j„l,u; Cor Leonid li ... Eeneb Aleel, Dencboh, Deneb 7 ... Algeiba "5 ... /r,.„„n « Leporis ... Am-jb (T LibnP ... Xuben el Genvbi /< — ... Xuben el Chamali ... Zubci Uah-ali .. Lvnc ... I'<;/IJ /-^ ... s;i./r«Jt' ... Sul„,hul .1 Uf.hiiK-l.i ... Ra» Alh,„j,i« ti ... C.balrai a Orionis ... Belelijeitx ti ... «.>! y ... Mlatrix 0- .. Minlaka ... Alnilam .. PiWei ... Maika; /< ... Srheal > ... Al-jenib ... Km/ ... Roman n Persei ... ilirfak /J ... .ALjol Minoris ... I'olan.- \i ... Kochab a VirginU ... ... Spiea Azimech, Spica ... Xavijnva .. Vimirminlnz June 30, 1882.] KNOWLEDGE Ifttersf to ti)t ©iiitor. [T3k* Editor doet noDioUhimffl/ rfi>poniiUf for fheopiniona of \ia eorretpondenU. It cannot undertake to return mtinttMcrtptt or to correrpond tritk their writert. AU inmvntra/iofu ehould he a* ehort a* po'title, coniietentlt/ icitK full and clear Uaie- enti of the tcriter'e meoninff.'] AU Editor^nl commnnicaiiont fhould he addreeied to the Fditor q/" KkoWLBDCI; the Fublithert, at the OJice, 74, Great (^een- llreet, W.C. AU Eemittaneea, Chequea, and To»t-0£lee Order* should be made fayahU to Vettrt. JTyman * Sone. ',' Alt lettere to the Editor riU be l^^nbered. ^or convenience of reference, corretpondenta, when referring to any letter, tcill oblige by mentioning itt number and the page on tehfch it appenrt. AU LeHrrs or Qneriee to the Editor rhieh rrguire attention in the current iene of tiuld reach the Publiehing O^ce not later than the Saturday preceding (T.) Lettereto have a chaBce of appeariDp must be concise; they mast be drawn op in the form adopted for letters here, so that they may go nntouched to the printers ; private comraanicationB, therefore, as well as queries, or replies to queries ^intended to appear as such) should be writteli on separate leaves. (IT.) Letters which (either because too ionp, or unsuitable, or dealing with matters which others have discussed, or for any other reason) cannot find place here, will fither be briefly referred to in answerato correspondents, oracknewledged in a column reserved for the purpose. " In knowledee, that man only is state of transition No than fiiity of opinion." — Faraday. " There is no harm in making a mistake, but preat harm in me a man who makes no mistakes, and I will show you i nothing."— 7*V6i>. " God's Orthodoxy is Truth."— CTar7« Elngiley. THE LATE MR. DUXITAN. We shonld be obliged if "J. L. W." wonld forward his address to Mr. Litchfield, whose address is given at the foot of a letter respect inp the late Mr. Dunman on p. 28 of Kxowledge, No. 32. — Editoe. TOBACCO AXD COXSUMPTIOX. [442] — The narration of a piece of personal eiperienco may not form a wholly valueless contribution to the discussion of the con- nection between smoking and an immunity from consumption. I may thankfully say that the solitary complaint from which I ever suffer is relaxed (or "gravelly") sore throat; and this only attacks me if I am exposed to cold or wet. If, however, under such cir- cumstances, I take a cigar, it acts as an absolute prophylactic, apparently by drying up the mucous membrane. It is fair to add that I often do not smoke for weeks at a time. It is quite possible that, were I an habitual smoker, tlio very valuable effect of which I have spoken might cease to accrue. As it is, to go out into the rain without my cigar means an infallible sore throat ; to " light np" as a preliminary step, assured freedom from it. W. N. [4-13]— The question of a possible connection between tobacco and consnuiption has been raised by a correspondent. Does tobacco smoking prevent or cure consumption ? This question is one of mournful interest to many English families, and it is one which we have some means of answering ; for although wo are, in common with most civilised nations, a tobacco-loving people, it is at present only the adult male portion that so indulges. If, then, it has any influence over the disease, wo should expect to find tho benefit so derived confined to men. Let us see what statistics have to teach us on this point. Dr. Boudin gives tho following figures (" Traitc de Geogrnphio et des Statistique Medicales," tome ii., p. 6-13, 1857) :— " In England and Wales, in tho year 1838, 27,935 males and 31,000 females died of consumption; 1839, 28,1C6 males and 31,133 females ; (with the exception of London) 1812, 24,018 males and 28,098 females. Tho fifth annual report of the Kegistrar- General (p. 398) gives the following death-rate by phthisis (consumption), in 18 H, in tho twenty-fivo large towns, comprising 1,883,093 inhabitants, and in seven counties having 1,700,431 inhabitants :— In tho towns, 1,279 males and 4,427 females ; in tho counties, 2,8S0 males and 3,510 females. The general death-rate from consumptive diseases was in | 1848, 31,573 males and 32,502 females; in 185), 32,278 males an " are far from indicating a predominance of consumptive affections amongst women, if one remembers that in nearly all the European countries the number of women exceeds that of men." Dr. P. C. A. Louis records (" Researches on I'hthinis," translated by Dr. Walshe, p. 479. 1844), a series of 123 cases, analysed and collected in wards containing 48 beds, equally divided between individuals of both sexes, 70 of which were furnished by females, and 57 by males. Dr. Louis in order to ascertain, if [wssible, tho influence of sex on the mean duration of the disease, says (p. 377) : — " I compared two series of individuals, one of them comprising 97 women, and tho other 113 men. I found that the mean duration had been twenty months in the women and seventeen in the men — a rather considerable difference, and one of the reverse kind from tliat which might have been expected, inasmuch as phthisis being more common in females than males, it might naturally have been supposed that the sex most strongly predisposing to the disease would also have hastened its progress." There is nothing in these figures, then, to show that men derive any benefit in the way of preventing or retarding consumption by the use of tobacco. And if we now turn to some other statistics, we shall find that the belief that women are more subject to con- sumption than men is not universal. Dr. A. B. Shepherd (Gulstonian lecture on the Xatnral History of Pulmonary Consumption, 1877), gives a table of 849 cases of ordinary phthisis (consumption) observed at the Victoria Park Hospital. Of these, 465 were males and 38-1 females. .\t the Lyons hospitals for this disease in 1873 were admitted 860 males and 569 females, or a proportion of the former to the latter of three to two. There is nothing very conclusive about these figures — the preponderance of male cases over female is probably due to the harder work and e.yposuro that is oftener the lot of men than women — although this must to some extent be counterbalanced by the baneful confinement of the female lower orders, from morning to night, in squalid dens and poisoned alleys. But be that as it may, there is nothing to show that tobacco has the slightest pre- ventive or curative power over consumption. May the day soon arrive when medical science shall discover a ctire for consumption. We have much to cause us to look con- fidently fonvard into the future ; and although unwi.«c legislatioD, the result of specious huraanitarianism, has checked the advancing tide of knowledge in England, yet men like Pasteur in Emnce and Koch in Germany, unhindered by a paternal Government, are making discoveries that shall redound to their glorj- as long as the heart has woes, as long as this world shall last. W. M. Be.\imont, M.R.C.S., Oxford. [444] — I have read with interest Mr. W. B. Wicken's letter (Xo. 411, p. 630) on Tobacco and Consumption, as also Mr. Prosser's reply thereto (No. 418, p. 28, Vol. II). Smoking tobacco as a cure for consumption, I am afraid, will never come to tho fore. Climate has, I hold, a great deal to do with the prevalence or scarcity of this disease, for wo find that it is most met with in moist temperate countries, like Great Britain, and is comparatively scarce in countries which suffer tho extreme oJ heat and cold. But another reason for the prevalence of consumption in this country (and in others) is the habit that human beings have acquired of breathing through their mouths, and not through their nasal organs. Tho air wo breath through the mouth gin-s down to the lungs unpurified, while that breathed through the nose is de- prived of obnoxious matter (with which tho air is always more oi less filled), that organ having the property of purifying the air breathed, as well as others. Mr. Pressor, in his letter, gives an example of this. He says that tobacco smoke has undoubtedly n soothing effect, for when his laboratory is filled with acid fumes, ho has no inclination to cough, as long as he uses his pipe. It is rot tho soothing effect of the tobacco fumes that prevents his ini;lina- tion to cough, but, while ho has tho pipe in his mouth, he necessarily breathes through his nose, and the air is purified (so far at least) before it reaches tho lungs, and causes no irritation. There arc many races of Indians who still possess this natural prnctice, and were it reacquired in this country, 1 do not doubt that consumption and other diseases of the lungs would become coin|>!ir«tively things of the past. W. Ul'ME. TURKISH TOBACCO. [415] — Your corre.spondent, in letter 418, is a little bit ont in regard to tho tobacco used by tho Turks for tho hookah nargilch. The tobacco used, and 1 have smoked much of it (yet cannot stand half a pipe of the mildest tobacco used in England), is called so ♦ KNOWLEDGE ♦ [Junk 30, 1882. '•lunbcki" — Persian tobacco. It is either very mild, or else the process it undergoes, before reaching the lunprs of the smoker, robs it v{ much of its strenj,nh. Before beini; placed in the nargileh it is muist«Ded, and then the moisture squeezed forcibly from it. Let Mr. Vrosser try to smoke the Knglish forms of tobacco — to wit, shag, birdsoye, retnms, gold leaf, &c., Ac. — in a nargileli, and he irill alter his opinion as to to the " tunbeki " of Constantinople j but then he only took "one puff." Another case of noglcctod opportunities! He missed the chance of making the ncquaintnnce of a smoke which does not depress you, after which you liaTO no desire to drink, and to which the lower class of Turks owo their furiitude under difficulties, their suavity of manner, and temperance in all things. ' A Co.\sT.tXT Keakeb. THE FEVER TREE. U6]— Mr. Sonthall, writing of the Eucalyptus Globulus, seems t think it has not yet been acclimatised in Europe. Perha])s I may be allowed to say that it grows luxuriantly all along the Biviera, and more particularly in the noighbom-liood of Cannes, and if acclimatisation consists in bearing flowers and fruit in the open air, it is certaiiJy there acclimatised, for 1 have seen there trees from s.xty to one hundred feet high, perfectly loaded with the bluish fruit, or more correctly seed-vessels, from which a pointed capsule is thrown off by the magnificent crown of white stamens and pistils which form the flower (there being, I believe, no petals). The seeds contained in the hard, woody case, nro nume- rous and extremely minute, much smaller than a grain of mustard eeed, and it seems diOiculf to imagine a tree — such as ono I saw, a perfect giant, growing in the gardens of the Duo de Vallambrosa, ■wh.re it had been planted only in (I believe) 1865 — having sprung from such a seed. The people of the south of France are greatly impressed with its efficacy in fever and rheumatism, for which latter disease they wear branches laid over the part affected, and you never mention the tree to a ]>easant without hearing : " Ah, it is very good for the fever." The manufacturers of Cannes use it largely in soaps and perfumes, and one prejiaration, a toilet vinegar, is the most exquisitely per- fumed and refreshing thing of the kind I have ever met with. It seems a pity our chemists do not make more use of a tree which has many capabilities, both as a febrifuge and a healthy and refreshing perfume. A. W. Bickla.nd. GLASS STYLOGRAPHS. [447]— WiU " H. L. C." (letter 424, p. 28, No. 32, Vol. II.) bo good enough to enlighten your readers a} to the way ho makes hia glass- tube pens (if not a trade secret) and oblige many others as well as ttis WllITEB. PROBABILITIES. [418]— Tlie remarks of " N." (401) having passed without com- ment, and fearing they may induce a belief in the advantage of a syotem of increasing or decreasing stakes, I wish to contribute my mite to dispel such an illusion in as few words as I possibly can. If a die be thrown a finite number of times, and any ono stake his money so as to gain a given sum per throw, and retrieve losses on unsuccessful throws, provided the gamester's resources are un- limited, it is evident that n trials ending with a successful throw will yield n m (or m per trial), and this will happen whatever odds may be laid ! But if the speculator is not possessed of unlimited rc- eonrccB, there is no advantage in varying the stake in anyway. If a single die Ije thrown ad infinitum, the number of times the die is onsticcessfuliy thrown on the second trial in proportion to the number of nntuccessful throws on the first trial, will bo as five to six ; the numtx>r of unsuccessful throws on the third trial, will bear the same proportion to the number of nnsuccessful throws on the second trial, and so on. The number of times the die is thrown successfully in proportion to the number of uusnc- ccssfol throws on any trial will be always as ono to five, the chance of throwing a die successfully always being the same, irre- spective of how many times it rnny have been thrown successfully or nnsnccesiifolly prerionsly. Any succession of successful or nn- succcMful throws is no guide to what may follow, notwithstanding the fact that the proportion of successful to nnsuccessful throws will ultimately assume the proportion of one to five. When a die is thrown a finite number of times, the greater the number of throws, the nearerwill the result approach the theoretical numbers ; for this reason, in throwing a die, the first time it is thrown suc- cessfully, the die will only onco have Iwm thrown on that particular trial, and that once sncccssfully ; if we continue to throw the die, the ratio U.'t ween the successful and unsuccessful throws on that particoUr trial will assume the proftortion of one to five, and the one successful throw on one partictilar trial will be farther re- moved, and the more times the die is thrown, the farther removed from the first trial will bo that trial in which each throw (one or more) is successful. There is another increasing stake to which the above remarks applj', viz., to win a given sum to- gether with ))nst losses, so that if an ovont happen n times in lit trials ending with a successful trial, you gain n times the sum you sought to win on the first trial. This is exemplified by tossing a i)enny, and doubling your stake each time you lose, reverting to the original stake after each win. Supposing tho resources of the gamester to be infinite, this is tho lowest rate of increment from which any advantage can be gained. There would bo no advantage in seeking to gain a given sum together with half tlie losses since the last successful trial. In games of skill and clianco tho most skilful player must ultimately win, as he is bonnd to get his share of the luck, and it is to his advantage to increase the stakes at the commencement of any fresh game, whether ho has been gaining or losing previously. In playing any game of pure chance, there can be no advantage from increasing tho stakes after a loss or a suc- cession of losses ; if the odds are against you, you must lose ; the higher the stakes, tho more you lose in proportion. Under any cir- cumstances thero is no advantage in following any system of in- creasing or decreasing stakes, or of investing so as to secure an increasing amount of money either after a loss or after a gain. No system has yet been or ever will bo devised that will convert certain loss into certain gain. If you cinnot gain by making tho stakes equal, you cannot by making them unequiil. Thomas Johson. Bromley, Kent, June 15, 1882. SPECTACLES. [•1U>] — Suppose you give us an article u]iou spectacles when convenient. A short time since I bought from a country dealer a pair of suitable focus, 30 inches, and capital frame. They wore by a celebrated maker, and marked by him as " pebbles." Their nominal focus proved to be exact, each lens gave a neat solar image at jjrecisely tho assigned distance, but on testing them between two nicol ])risms, I found no change of light or colour, such as is ex- pected from quartz in polarised liglit. Having a favourable opportunity, I submitted tho sjioctacles for the several opinions of three practical opticians in Loudon. The first said tho polish was apparently too perfect for glass i but placing on a table before the window a pile of common window glass, eight or ten pieces, perhaps, about C inches sqiniro — a polariz- ing bundle in fact — he held a tourmaline before tho eye with one hand, and a lens of tho spectacles in the other in the lino of sight between the tourmaline and the plates, and at once pronounced tho material to be glass and not quartz. The second roi'oroo jjroduced a pair of tourmaline tongs, and placing a spectacle lens between them, gave tho same verdict. Ho showed how, when tho tourma- lines were "crossed," tho rotation of a "pebble" lens between them restored the light at certain intervals ; whereas tho introduc- tion of a glass lens produced no effect whatever. Tho test of tho third was simpler still : ho touched a Ions of tho spectacles with the tip of his tongue, and said it was " not cold enough for pebbles," remarking that this was tho advantage possessed by quartz lenses — they were cooler to the eyes. Now, is there anything in this ? Does tho question of specific heat really arise ? or is the advantage only that of superior hard- ness, as compared with glass, and consequent loss liability to scratching ? Tlien, too, supposing it to bo conceded that quartz is tho bettor material, is anything gained by employing sections cut at a certain angle with the axis of the crystal, as is maintained by at least ono London optician ? Another, of equal eminence, asserts that pro- vided the (|uartz bo pure, free from stria) and bubbles, and uniform in density, you may cut it into slices for spectacle lenses where and how you like. Certainly the various appearances which are presented in the polariscope by quartz crystals, according as they are cut parallel to, at right angles, or at different angles with the axis, may indi- cate that it is not immaterial to the lens of tho eye, what section of the crystal be taken. But on tho other hand, tho eyo does not often use polarized light with spectacles. T. S. B. THE FIFTEEN SCHOOLGIRLS. [450]— Tho best way t'hat I can think of to manage tliin problem is the following. Designate tho girls by tho letter C and the num- bers 1 to 14. Let one group for tho first day's arran^fement be C 1, 2, and set the numbers 3, 5, 9 as tho first members of three other groups. With 3 join any other odd number (not already used), and an even number, which must be, with 7, 6, or 10; with 11, 8, or 14 ; with 13, 0, or 12. With 5 join numbers formed from those with 3| Jdne 30, 1882.] • KNOWLEDGE 81 by doubling the odd number and subtracting 1 oi- 15, and doubling the even number and substracting 2 or 16. With 9 join numbers formed in the same way from those with 5. This will complete four groups, and the fifth group will consist of the remaining numbers, either 4, 6, 10, or 8, 12, 14. Make the second day's arrangement by adding 2 to every number in the first day's, except 13 and 14, from which you must subtraci 12. Make each day's arrangement from that of the proceding day in the same way, and the problem is solved. Any solution may be varied by making the odd and even numbers change places — that is, each odd number changing places with the next greater even number. The explanation of this solution is that in the first day's arrange- ment one odd number is combined with another differing from it by 2, one with another differing from it by 4 or 10, and one with another differing from it by 6 or 8 ; and it is the same with the even nimabcrs. Also the combinations of odd and even numbers are such that one odd number is combined with an oven number 1 greater, one with an even number 3 greater, one with an even number 5 greater or 9 less, 7 .. 7 „ 9 „ 5 „ 11 .. 3 „ I. » J) 1 less. These differences are not changed by the successive additions of 2, except by changing a difference to what we may call its comple- ment, as + d to -f (J — 14. The place of every number in the first day's arrangement will in the coui-se of the six following days bo occupied by every other number of the same class (odd or even as the case may be), and consequently every number will, in the course of the seven days be once joined with C, and once with a number differing from it by each possible difference, whether the difference be added or subtracted. This method is applicable with slight modifications to most other Bcboolgirl problems, where the number of the girls is 13 n + 3, and not otherwise ; but in some cases, and as 1 have particularly noticed in cases of 60 ?i — 9 girls, there are difficulties in the way of applying it which 1 do not know aay simple way of getting over. For better illustration of the method of solving other problems, 1 add one solution of the problem of thirty-nine schoolgirls. Make a series of odd numbers beginning with 3, by doubling each term and subtracting 1 or 39 to form the next, and set the series down in pairs thus : — 3 5 8 9 17 26 With each of these pairs join the 33 27 22 oven number which is the sum of 15 29 6 the two numbers composing the 19 37 18 pair, deducting 38 if greater than 35 31 28 38. These numbers are the same 23 7 30 as the even terms in the series of 13 25 38 odd numbers, each increased by 1. 11 21 32 Now take the odd terms in that — series in order, add 1 to each, and 4 10 34 set them down in threes, as is here 16 20 36 done. 24 14 12 Those sets of three, with the addition of C, 1, 2, form the arrange- ment for the first day, from which the arrangements for the other days are formed by successive additions of 2 or subtractions of 36. Algkrnon Urav. MISPLACED SPA. [451] — The efflorescence mentioned by "Curiosity" has been found by chemical analysis to vary considerably in composition. It often consists of sulphate of magnesia, also sulphate of lime, of carbonate sulphate, or nitrate of soda, of chloride of soda and potash, and carbonate of potash. It is attributable sometimes to the bricks or stones of a wall, sometimes to the mortar. In bricks burnt with coal fires or made from clay containing iron pyrites the sulphur from the fuel converts tho lirao or magnesia in the clay into sulphates. When tho bricks are wet thcso dissolve ; wlion dry they evaporate, leaving crystals on the surface. Many limestones oonuiin magnesia; these are acted upon during calcina- tion by the sulphur in tho fuel ; sulphates nro formed which find their way into tho mortar and produce tho oilioroscenco mentioned. Again, the sulphur acids evolved from ordinary house fires attack tho magnesia and lime in tho mortar joints of chimneys ; these dis- solve and evaporate on the surface. Tho formation of chlorides is nearly sure to take place if sea sand or sea water be used, or in bricks made from cl.ay which has been covered by salt water. " Prevention is better than cure." The best plan is to avoid all tho materials above mentioned as likely to give rise to efflorescence, in tho case of bricks; clay con- taining pyrites or much magnesia should not be used ; special bricks may bo burnt with coke or wood. As regards mortar, tho use of limestones containing magnesia to any gieat extent may generally be avoided. If, however, it does occur, in spite of all precautions, the following remedies may be tried : — In the case of ashlar work, the surface may 'bo covered with a wash of powdered stone, sand, and water, which is afterwards cleaned off. Tliis fills up the pores of the stone, and temporarily stops the effiorescence. When tho wash is removed the efHorescenco will recommence, but in a weaker degree than before. Painting tho surface is sometimes eflicacions if it is done before the efflorescence commences. The mortar before use may be treated, to prevent it from causing efflorescence by mixing with it any animal matter. W. H. Peetwee. EXTINGUISHING CANDLE-FLAME. [452] — I do not know whether it has ever come under your notice that an ordinary wax candle may be blown out without leaving any red-hot snuff. Jf the candle be drawn backwards so that tho flame envelopes the wick right to the end, the burning of the latter is quenched, for the obvious reason that it is in the heart of the flame where no air can reach it, and a sudden puff at this juncture puts out the flame and wick too. Tho proper direction to blow in is that of the tangent to the curve of the wick from the end of tho latter j in fact, the experiment can, with care, be made to succeed withoat moving the candle at all, if attention be paid to this point. I have also noticed that tho third envelope of a candle-flame can be made distinctly visible by burning a little sodium in the neigh- bourhood of tho flame, so that, from being faintly blue, it becomes tinged with yellow, and can be seen, in spite of the luminous layer inside it. C. L. B.vbxes. SECTIONS OF A CONE. [453] — In drinking a glass of water, as the glass is sloped towards the lips the surface assumes an elliptical form. It has strnck me that since it was thus possible to obtain a section of a cylinder, a somewhat similar contrivance might be used for demon- strating the figures commonly known as " sections of a cone." My idea is simply this — to make a hollow glass cone, and partially fill it with any tinted liquid. By giving it different degrees of inclina- tion, the surface of the liquid might be made to assume the form of any conic section, from the circle to the hyperbola. Further, it the apparatus were so arranged that the liquid occupied exactly half the capacity of the hollow cone, we conld obtain tho limiting form of two straight lines, by holding the cone so that its axis should bo horizontal. I think tho advantages of this system are many and obvious. First, it would bo cheaper than the wooden sections now in use, which requii'e delicate workmanship ; secondly, it would have the advantages of comjiactness and completeness, and would run no danger of being lost piecemeal ; and, lastly, the demon- strator, by a motion of tho hand, could actually show the ellipse in the process of passing off into cither of its two limiting forms — namely, tho circle or the parabola — and thus attract tho attention and interest of the pupil. George E. Cbawkoru. Amongst tho coming electrical exhibitions, that to bo held at Munich in the autumn will be of csjiocial interest, ns it is tho intention of tho authorities to use, as tho driving-power for tho dynamo-machines, tho water-force of the river lear, estimated at 3,000 horso-power, and to prove that it is possible to make use of it to light, at a distance of some miles tho streets and houses, and to distribute tho force to the different workshops. Pricks or Books. — Tho following very sensible paragraph appears among tho answers to correspondents, in our valuable con- tempornry, tho Schnul llnaid Chronicle : — " ' Educationist ' writes : '1 should' bo much obliged if yon would add tho price of the books you so excellently rovicw,' observing that 'thoy may bo 8ix|>oncc or a guinea, and no ono can toll.' — Wo have had from time to lime many commnnications from our readers in various jmrts of the country to the game effect. We can only say that it would give us great pleasure to affoni this information to our reailors^ but wo owe also some consideration to tho proprietors of tho School /i.xinJ Chronicle, who naturally consider it to bo tho duly of thi- publii>hcrs of the books to inform tho public through our advortising columns of tho jiriccs of the books which wo review. In a largv pro|K)rtion of cases this information will bo found auioiig our ndverlisonionts, but not nccossorily in tho same week in which tUo review appoara- We think publishers would consult their own interest by announcing tho prices of tho books inimcdiatoly after tho api>carauco of tho reviews." 82 ♦ KNOWLEDGE [June 30, 1882 anstorrsf to CorifSponijnUg. ((f KsoyiLiBai, Uu information AU t*mmtMctH»mM ftr tU Bdilor rtfMirimf tarif >■ T itfoTt Ikt SattrJiij prtrrdf} Ike nrrnt iuii <••/ nmlat>a» ^ K»ir» rtmftU mi to go to frtu tarl) rrs to Co»l«sro!ir»!iTS.— 1. A'o quntionM a»J-i»j /or tcintijl. ' autvfTtJ tkrcmgk tktfott, i. lftter$ irnt to the Editor fore t be forw,rrJe4 ; nor eon the namet or addreuee ^f eorreepondeuti be given in r to fnctite tmqninet. 3. CorreepondentM ekomld ttrite on one tide onlg of Ja>. Ufjis. On re-reading, yonr lelter seemed not to contain tlie direct positive evidence necessary to make such cases scientifically useful.— \V. H. Bi-TcnART. Mr. W. Maltieu Williams has not yet published his promised work on " Comets and Xebuhv." — R. Shewaed. I fear it is hardly in favour of your theory of solar energy that it is "distinct and separate from any known." I do not rvmember any true theory of which this could be said. At present, however, my chief difficulty is that the theory could not bo condensed into less than ten pages of Knowlkdge. Perhaps, if you published it elsewhere, we might manage to give the essence of it in less space. — E. D. G. We agree with you that Col. Ross's defini- tion of analogy is incorrect. As in mathematics, " Analogy or pro- portion is the similitude of ratios," so in general anology signifies the similitude of relations, not resemblance between things. — A. McLean. Many thanks. Your suggestions are all eicelleut. I proposed such a publication to one of the principal publishers of Victoria ; but his idea wus that it would hardly pay. If readers of Knowledge would not object to a series of maps doing for the southern hemisphere what those now publishing do for the northern, that would bo a convenient way of producing the work. I think many, though living in the northern hemisphere, might like well to know the aspect of the constellations in the southern skies. — C. L. 13. Let A B C be any triangle ; P, Q, R, the centres of equilateral triangles on A B. B C, A C. Through A, draw a straight lino parallel to P R, meeting the circles circumscribing the equilateral triangles on A B, A C, in <• and b respectively. Thus it is obvious that b B and cC produced must meet on the circle circumscribing the equilateral triangle on B C (since the angles at 6 and <■ are each one-third of two right angles). The triangle a b c is equiangular, and, there- fore, equilateral. But b c being the greatest chord which can be drawn through A to the circles b, <-, it follows that 6 o and c a are also maximum chords. (For if longer chords could be drawn through B and C, their extremities wonld give an equilateral triangle circumscribing ABC, greater than ab e, or be would not be a maximum chord.) Hence b a and c a must be parallel to P Q and RQ. (For it can e.-usily be seen that the maximum chord drawn, as 6 o is drawn is parallel to the line joining the centres P and Q.) Hence the sides of the triangle PQK, are parallel to thoso of the triangle a be, or P Q R like a fc c is equiangular, and therefore is equilateral also. — Constant Reader. Your query .seems in some way to have gone astray. We certainly put it in our box to forward to the writer of electrical articles, but suppose it was not sent. — BsiTANNlCfs. Would not the effect of the Saturday artillery prac- tice be to produce heavy rainfall on Saturday and Sunday, if at all ? Is there any evidence of a heavier average for these days ? Again, the rainfall would be limited locally. Is there any evidence to show that there is this local effect ? That under particular atmospheric conditions heavy cannonading may bo followed by rainfall may be true enough ; but " all great battles by land and sea " have not been followed by heavy rains within twenty-fonr hours.— F. N. New- coke. We might be able to find space for an occasional short article on sulijccts connected with India, China, or Burniah, if having a scientific bearing. Occasional notes on actuarial matters would al»o be welcome.— S. Middleton. We have forwarded your obliging commnnication to Mr. Haviland. who is now in yonr town. — TKfTiiFtr. We may shortly have something to say on bicycles, but for *oai'/i-txcrci«e the best use that can be made of a bicycle is to exchange it for a good, light-running tricycle. Bicycle-riding must Ijc regarded as the liold and clever achievement of a ilidicult and hurtful feat. Consider the cramped, awkward, chest-com- pretsing attitude of the most skilful bicyclists in riding, and note how they walk, and you will sec that their exercise cannot bo good for them. — W. S. BaofiK. Many thanks for your kindly and en- cooraging letter. In part of our last issue the final result of the Vienna Tournament was given. As we went to press before the final ronnd wan over, yon can understand that the first copies could not have it. — Lorekhith. Yonr answer to yonr question 2 ia qoiU; correct. As to the other question, the thing to be proved is not true anieas n does not exceed a in a certain degree. For instance, the integral part (it (v/a' + 1 + a)' is even when a^l and n-10; I make it C72GO. go, again, when a- 2 and n-10, the integral part of the expressions is even — namely, lisGOSO. Your rcjily to Pynuuus's question is not clear to me. Why should there bo an increase of 180 each your, when it is obvious that after a few years more than 12 will get their advance ? — Ed. P. Toy. No conjuror who valued his repute would trust to a person choosing '■ a lion " for animal, and " a rose " for flower ; as you say, 80 out of 100 would, even if that proportion really hold. But I'hnvo asked many the question you suggest, and I find a much greater number siiy "horse" and "dog" than "lion," and though "rose" has a slight preference over other flowers, " daisy," " butter- cup," and " heartsease," are chosen nearly as often, while "pink," "wallflower," "violet," and "primrose," are not far behind. I should say about a tenth choose " rose," leaving the other nine-tenths for all the other flowers ; but cer- tainly not so many as one-twentieth select " lion." Supposing the chance one-tenth that a rose would bo selected by anyone taken at random, and one-twentieth that a lion would be selected, the chance that both would bo selected is oue-two-hundrodth, or there would be 199 failures to one success. Taking even your numbers — 80 out of 100 for each— the chance of both being selected would bo G,IOO ten-thousandths, or there wonld on the average bo tliirty-six failures in 100 trials — far too many to leave a conjuror a shred of reputation. — J. W. D. Chcrchili. Thanks ; but I doubt whether so many take interest in the matter as you think. ELECTRICAL. A. Neal. l.The lumj) is constructed al'ior Swan's tlcsigii, but may be only a catch-penny. Light is emitted by all parts of the filament proper, but sometimes the connecting copper or platinum wires extend some distance into the bulb. Apparently so in your lamp. You can increase the candle-power by increasing the current. 2. RuhmkorfE induction coils can be procured at all prices, from 13s. or 14s. upwards. 3. We intend writing on secondary batteries immediately. — P. C. F. The statement that, in driving a dynamo by steam the UP is in inverse ratio to R, although at first sight paradoxical, is quite correct when only E and R are given. HP is proportional to EC, that is, is proportional to C, E being fixed ; bnt C is inversely proportional to R, therefore UP is also in inverse ratio to R. If C and R are taken, then, of course, HP is directly proportional to R, C being constant, because E increases at the same rate that R does. Taking C'R= -jt- = CE, whichever of these identities is used, the result is the same. Virtually, C and E ai'o the only quantities from which U P can be obtained. Inasmuch, how- ever, as C and E are associated with R in the manner expressed by Ohm's Law ( C = jr-) i knowing any two of these throe quanti- ties, we can readily ascertain the third. To simplify matters, suppose we use a generator of low internal R, and whoso E is 50 volts, to maintain incandescent lamps arranged in multiple arc. Then, if each lamp offers, say 25 ohms, the current through each will be 2 ampt^res. Manifestly, the U P developed will bo directly as the number of lamps, but the R will be inversely proportional (from the law of parallel circuits). Joining the lamps in series will com- pel US to increase the E as each lamp is added. C being kept con- stant, the H P will be directly proportional to the R in the circuit. But in each case 'H P. By taking several of numerical examples, and working them out, identical results will be arrived at. — Alexander Howell. The colouration of phosphoric acid, when dropped on your induction coil, was not due to electrical action, but in all probability was the result of the chemical actiou of the acid on the organic colouring matter used for dyeing the silk or whatever else may be the substance of the insulating material. TUE TELESCOPE. Comet. — " Portable Equatorial " is a vague term — so vaftne, in fact, that we cannot give a definite answer to your qsestion withour you describe your form of mounting. In order to get at the Polar region of the sky, your telescope ought to he mounted at one end of the declination axis, being counterpoised by the declination circle and a weight at the other. Of course, every equatorial stand (to bo used as such) must bo a fixture, its Polar axis remaining, under all circumstances, parallel to that of the earth. If you will be a little more explicit in your description, wo will try to help you.^.T. W. CofLBORN. No ordinary two-inch tele8C0|ie will bear a higher power than 160, and it must be a very good one to perform well with such an amount of amplification. In order to obtain thin power on your own instrument, yon will require a Huyghenian eye- piece, whereof the fdcns of the field-lens is 0-35 inch, and that of JoNK 30, 1882. • KNOWLEDGE the eyelenB Oil inch. These lenses must be placed 0 23 inch apart with, we need scarcely add, their plane sides towards the eye of the observer.— Lancasiuee will find that selenography will supply him with work at once interesting and useful. The study of the Solar surface, too, may be pursued with an instrument of the size of his, and the addition to it of a Browning's Star spectroscope will enable him to see something of the spectra of the prominences on the solar limb, to say nothing of its use in Stellar spectroscopy. Should ho possess artistic taste, and be able to sketch, careful drawings of such planets as Mars, Jupiter, and Saturn, if made at intervals, possess a direct scientific value. His best plan, however, wi'l bo to purchase forthwith Webb's admirable " Celestial Objects for Common Telescopes," which is in reality a pocket Encyclopaedia for the amateur observer. — KxCEtsiOB. 0 Ilerculis, as viewed on the meridian, with an ordinary inverting eye-piece, now presents the appearance of a large star, ^vith a very much smaller companion almost horizontally to the left of it. We have not a copy of " Half Hours " at hand ; but cer- tainly no such change as your diagrams indicate has taken place in this star. Its position angle has varied some 22° during the last eighty-two years. Prior to the year 1871, the comes was below a horizontal line to the left of its primary ; now it is just above such a line. We do not know upon what authority Castor is described as a ternary system in Nollwyn's " Astronomy." At any rate, no sensible change has taken place in the relative position or distance of the principal star and the 11' magnitude one since the year 1823; and the system is universally regarded among astronomers as being simply binary, the minute star having obviously no physical con- nection with" the well-known pair. With reference to Pollux, the word "coarse" was used as expressive of th*^ < — .,^^,...^l.^.. .i.'^tnnce of the comites ; "fine," as referring to the i ^^■hen Pollux is on the meridian on a dark night, yi t two companions up, both to the right, and a lii:,' i i ' :;.iiiital line passing through their primary. The larger slur it tiie two is about half as far again from Pollux as the smaller one. This last will require some looking for ; though, when caught, it may be held steadily enough in a good three-inch telescope. The earliest recorded position of comet Wells is on March 19 6894, 1882, G.M.T. ; when it was situated in K.A. 17° 54' 38-1", and declination 33° 25' 5" X. (which possibly ought to be 33° 24' 5" N.). Long Distance Teiephoning. — Recent experiments have been made with M. van Bysselberghe's system of telephony, during which messsages were sent by telephone over a long distance simultane- ously with telegraphic messages traversing the same wire. The first experiment was made on an ordinary telegraph wire 353 kilo- rafttres long, between Paris and Nancy ; and the second between Paris and Brussels, over a wire 344 kilometres long. It is stated that telephonic messages were distinctly heard, whilst the tele- graphic messages were distinctly rendered by the Morse instru- ments employed. M. van Eyssclberghe is the head of the Meteoro- logical Observatory at Brussels. Electbic Light in the City.— At a meeting of the Commissioners u**r em- ployed—with the slate o/ the rails — and so on. But the differen- tial calculus deals only with those quantities which vary according to some definite law. For example, when a body is let fall from rest tho distance it traverses varies, according to a known law, with tho time elapsed since the fall began. The differential calculus is able to deal with such a case as this. Again the sine of an angle varies accord- ing to a known law as the angle changes ; and the differential cal- culus is therefore able to deal with this case also. Now we can at once see the importance of a calculus which will deal with variable quantities. Algebra and geometry and trigo- nometry deal with absolute quantities. But it is often verj- necessary to learn something about the variations of quantities, to know when a variable quantity attains its greatest value, when it is increasing, when diminishing, when it changes fastest, and so on. Whenever variations take place according to a known law, this is precisely what the differential calculus will do for us. And its great advantage is that it will solve our problems systematically. An ingenious application of algebra or geometry or trigonometry will often enable us to solve problems which belong especially to the differential calculus. But we require ingenuity for the purpose, whereas the differential calculus solves such problems with cer- tainty, even if wo have not a particle of ingenuity, so long only as we follow tho proper rules. Even where it fails, it teaches us that we are trying to solve an insoluble problem. The first matter the calculus attends to is tho choice of a con- venient expression for the rate at which a rarioblo quantity charges. This expression is called a differential coefficinrt. 1 prefer to illustrate rather than to define it. I wish also to illustrate it in such a way as to remove at the outset the chief stumbling block of the student of this special department of mathematics. 1 take, therefore, a familiar case of a varying quantity : — When a body is let fall from rest, wo know that as it falls its velocitv continually increases. Now this varying velocity affords • very good illustration of a differential coefficient. The velocity of a body may bo described as the rate with which the 8|>aco it ho» traversed is increasing, as tho time elapsed increases. When we change the time, wo change the space traversed. But unless the velocity is uniform, tho change of space is not proportional to the change of time. In the case of a falling body, tho velocity is not 84 KNOWLEDGE [June 30, uniform; so that, if we consiJer one instant, the rate at which tho si>ace traversed would change for any given interval of time would bi different from tho corresponding rate at some other instant. Reganiing the matter as illustrating the differential calculus, tho drst thing to be found is a general expression for tho rate of change, — the law determining the space traversed being supposed known. Consider now the following way of dealing with the problem : — At the end of t seconds the body has fallen a space repre- sented bv i 9 i\ where p represents the accelerating force of gravity (or numerically, a foot being taken as the unit of length, and a second as the nn'it of time, a = 32-2). A second later the body has fallen altogether a space represented by J J (« + 1)', so that m the course of that second the space actually traversed liy the bo THE PLAY. JfoiE.— The card anderlined wins the trick, and card below leads next round. EEMAEKS AND IXFERENCES. 1. A leads correctly from stiit, ^ Y S Z headed by Ace, Queen, Knare, &c., see leads. T begins to signal, haviug four trumps, two honours, and a good suit, his partner also having turned up the King. A alone knows, so far, that 1' is signalling for trumps. 2. A shows that he has led from Ace, Queen, Knave, ten, and at least one small one. T completes the signal. T knows that neither B nor Z has any more Diamond s. A and B know that Z has no more. 3. B knows that T holds Two and Four of Spades, i' knows that B holds the Queen and at least two others, unless, which is un- likely, B has led from a three card 4. r knows that Z holds Two of Clubs. 5. Z returns the highest of two Clubs left, and Y, knowing that Two is with Z, at once places the remaining four Clubs with A and B. It is more probable that they are equally than unequally divided, and as A plays the ten, the chances are in favour of the Queen being with A. But at any rate, the finesse of Knave would be cor- rect. 6. T is now, of course, sure of drawing two trumps, remaining with the long trump. 7. T's purpose, of course, is to draw B'b Queen of Spades, remain- ing with the tenace iu that suit, and entire command, should Bkeep to his suit. But B sees that whether he finesses the Ten (successfully) or takes the trick with the Queen, Y and Z mnst win, it besides the Two and Four of Spades already placed in his hand Y holds Knave and another. For Y has two Diamonds left, and if ho held originally five Spades, can have no Hearts. So that if B takes two tricks in Spades, V will make two tricks in that suit, whatever B may lead, besides his long trump. Or, at the score, V X would win two by tmmpg. There- fore, B plays for the only chance left, viz., that A may lie over Z in Spades, and bring in his Dia- monds. This comes off, and 8. 9, and 10. A makes two tricks in Diamonds, and forcing Y with the thirteenth, compels him 11. To lead through B'a tennce. A B win the odd trick and the game, tricks counting before honours. T should at trick 7 have playe' / the game, unless ii finessed the Spade 10, which he might very well ayoid as dangerous. 0 ol 1* A IP <7 1 'a a 1 ' 0 1 4.VA 1^ ' 0 O A A > ) 3. P toQBt I. 1! takes P 5. Q to B2 (.) 0. Q to Kt3 (<•) 7. B takes P (ch) 8. Q takes P 0. Q tukos R 10. Kt to B3 11. K to Bsq 12. P takes B 13. Kt to K3 14. Q t,-»kes R 15. P takes P 10. K to Kt sq 17. Q takes RP 18. Q to Rl 19. Kt toQl 20. K to Kt2 21. Kt lakes B 22. P to K4 23. Qto Ktl 24. R to Bs.) 25. Q to K2 20. Q to K3 27. Q to R3 (ch) NOTES. (n) Tliis is one of the many oiporimenta in the openings which Steinitz has made during the progress of this tourney, some of which resulted disastrously for him, his first game with Zukertort S6 KNOWLEDGE * [June 30, fonninff a most Indiorons example. Stoiiiitz adopted this move acrtvinst Floissijr with some success, as can bo seen from the gamo I^ublished in * former number. (b) This seems a pert reply, for in case White should take the Pawn, then Black retakes with the Knight, having thereby won a move; or if White support this exposed Pawn, then Black could further proceed to develope his game by attack on the advanced position. (.-) A f.'ood move, having for its object the attack on the lonely outpost and also B to Kt5. (J) This was either an oversight or an unsonnd combination. (f) If 6. P takes P, then Q to R5 (ch) would give White the Ijettcr game. On the other hand, by playing Q to Kt3, Black .klmost obtains a winning advantage at once, on account of tho iuable attack on White's QKtP and KUP. (/) He elects to give up tho Rook rather than the KnigVit, as Wliito obtains some considerable attack, but this is very adven- I iirons play. (j) Playing after Morphy's fashion, he gives up tho second Eook in order to be better able to attack, as the threatened check with the Black Queen on Q5 somewhat hampers White's movements ; bat it is altogether an ertraordinary style of play, where issues of the highest importance arc at stake. The position, however, is pregnant with ingenious combinations. We give a diagram. Position after White's 11th Move. 1 # M i 1 Slcinilz. (h) This move cost White £70 and the First Prize, lie could h.ive effected a draw by the following play : — Q to KR5 Q to R6 fch) Kt to K8 Kt to QC (ch) and draws. Kt to Kt3 (forced) K to Kt sq KtoB2 for if K to K2 K to Qsq Q to Kt7 (ch) Kt to B7 (ch) and perpetual check. .\s.^nminp that Steinitz saw tho draw, ho ought to have gladly :.v.iil. .1 himiielf of it, as, considering be is minus two Rooks, his "ail not founded upon sound judgment. The proper reply ; r riiovo would be fatal ; for if (^ takes Ktl', then Q takes HP, ■■ iitr mate cither on U7 or lib, whereas now White cannot • HP, as Black can reply with Q takes Kt (ch), followed by Kt to HI. (i) Kt to B5 looked a very promihing moTC. Black's only reply \r&> Kt to Kt3, but some interesting play might have resulted. White might also have tried Q to QR.5, in which case Black would lave been compelled to play B to Kt2, giving up tho Bishop, or , kowise Q to KK5, in which case Kt to Kt3 is forced, then I"*. Kt to Bt or Q to B3 would have given more chance to White I han he obtained in the actual game. ANSWERS TO CORRESPONDENTS. •»• Plecue addrett Cheti-Kdilor. Correct solutions of Problem 45 received from John O'Kecffo, J. Napier Belmont, Charles Hartley, A. B. Palmer, .John Watson, C. W. Croskey, H. A. N., Borrow, Witton-leWear, Herbert Jacobs, Leonard P. Siees. Borrow.— You are quite right. B to B4 would have boon a better move. Herbert Jacobs. — Problem received, with thanks. Leonard P. Hees. — Problem received, with thanks. You are right, tho pawn on B3 is rather suggestive, but wo have put it there oui-selves. Perhaps in your ncitt you will tell us why. Comet. — Correct solution of No. 42 already published. Co.sT OF THR Electric Light. — In a letter to the Timet, Mr. Crookes, F.R.S., has given tho result of several months' experience with electric lighting in his own house by means of gas-engine and incandescent lamps. Omitting tho interest on capital expenditure, which would not obtain to anything like tho same amount by lighting from a central station, especially when reduced cost in keeping ceilings and curtains clean and maintaining gilding and book-bindings is taken as against it, ho finds tho actual cost to him to bo £2. lOs. per month. Gas lighting to tho same extent, he Bays, would cost £3. 6s. Pd. He has in his ^houso altogether about fifty lamps of different powers. ANTnnoroi.oGic.\L Institute. — Juno 13, General Pitt-Rivers, F.R.S., President, in the chair. Mr. Mann S. Valentine, of Rich- mond, Virginia, exhibited a series of figures carved in steatite and mica schist, forming part of a largo collection found by him in Virginia and North Carolina. Tho whole collection consists of some 2,000 specimens, consisting of various animals and household utensils, cups, Ac. 'The human beings aro all clothed, and are represented riding on animals and sitting on chairs, and indicating a i-emarkably advanced state of civilisation ; and in some instances obvious traces of contact with Europeans. Mr. A. H. Keane de- scribed the district in which tho objects had been found, and the tribes that were known to have inhabited that country. The following papers were read : — " Nepotism in Travancore," by the Rev. S. Matur; "The Laws of Madagascar," by Dr. G. W. Parker; and " Cummer, Co. Wexford," by G. U. Kinaban, Esq. Contents of Knowledge No. 34. riei Ladies' Drpss Society Found Links. -P.rt VIII. By Ur. A. Wilson F.R.S.E., F.L.S. {IlluHruledl Tboucht-Beadiner. By tho Editor... Crystals. By William J»go, F.O.S., (lllutlraUd) English Snuide Health Kesorts. By Alfred Uaviland Tho Eyca of Science. By tho PhotoCTaphy for Amatenra. By A. Brothers, F.E.A.8. Part X On some Publications of the Chria- tian Enowledijo Society NOTICES. .lumo of Kkowi-iidoi! is now ready, bound in red cloth, gilt lOs. 6d. Vol. I. contains the nurabors from the commenee- 1«81) to No. 30 (May 2«, 1882). As there is only a limited Publishers advise that orders should be sent ia without Binding Cases for Volume I., price Is. (including Title, Indei, and Caae) for 2s. ed. The Post-office regulations prevent the transmission of volumes and cases through the post. The following Monthly Parts of Knowlbdob are now to be had (Farta I, aad II. being out of print) : — Pabt III.— (Jan., 1882.) Containing four numbers. Price Ind. Post-free, Is. Paet IV.— (Feb., 18f2.) Containing four numbers. Price Kid. Post-free. Is. PiBT v.— (March, 1882.1 Containing five numbers. Price Is. Post free, la. 2d, P»BT vr.— (April, 188J.) Containing four numbers. Price lOd. Post-free, la. PiBT VII.— (.M«), 1882.) Containing four numbers. Price Ind. Post-free, la. VxKX VIII. -(.lune, 1882.) Containing Hve numbers. Price Is. Post-free, Is. 2d. Subscnbers wishing to complete their Sets are advised to make early applicatioa to the Publishers, as no further reprinta will be ordered. Thet TERMS OF SUBSCKirriON. of Annual Subscription to the weekly numbers of KjrowiBDOB ara 10 lo' follow To any address in the United Kingdom To the Continent, Australia, New Zealand, South Africa & Csnad To the Uniled Slates of America »3.26. o To the East Indies, China, &c. (ci<2 Brindisi) All subs^riptic P. O. Orders and cheques shou Wthah k SoKB, London, Agent for America— C. 8. Carter, i New York, to whom subscriptions cai I advance. OFFICE: 74 A 75, GREAT QUEEN STREET, LONDON, W.C. KNOWLEDGE • 87 PLAlNLY'^f ORIjED -£XACTLffljESCRIBjE|^ LOSDOX. FRIDAY, JVLY 7. 1882. Contexts op No. 36. PA6>. r^ci. Alktiqnitj of Man in Western , Future Sources of our Food Supplr : Eniope— rv. Bj Edward Clodd. 67. Ansfralssia. Bt Percy Boasell.. 92 How to Get StroDg— III. (/««»- I Shakespeare Studies W «w9 FngHsh Seaside Health- Resorts, I Our Mattiematieal Column 101 By Alfred Hariland, M.H.C.S., Our Chess Column 103 F.B.M.C.S. Lond 91 Our Whist Column IM I ANTIQUITY OF MAN IX WESTEEX EUROPE. By Edward Clodd, PART IV. KENT'S HOLE, or Cavern, Ues in a hill in the vale of Ilsham, about a mile eastward of Torquay liarbour, and half-a-mile from the coast. It comprises, as the openings in the face of the cliff indicate, two caverns which run parallel with each other, widening here and there into chambers to the extreme limit, when a passage connects them. An inscription in one of the chambers, known as the " Cave of Inscriptions," shows that some curious traveller had wandered into its recesses nearly 200 years ago, and it was partially sur\-eyed in 1825 and following years ; but it is to the systematic research and unceasing superintendence of Mr. Pengelly since 18G.5 that we owe that full knowledge of its contents from which irrefragable conclusions con- cerning the high antiquity of man in this quarter of the globe are drawn. Entering the eastem'division, to which the labours of Mr, Pengelly and his committee have been restricted, we find the deposits to occur in the following order, beginning with the uppermost : — Xeolitiiic, — 1, Blocks of limestone.'wcigking from a few pounds to npwai^s of 100 tons, which have fallen from the roof nndcr the action of frost, Ac, and of which mnny are cemented together b_v carbonate of lime, i.e., stalai^nitc, 2, Black muddy mould, from three inches to as many feet in thickness ; composed almost entirely of decayed vegetable matter. Pal roLtTHic, — 3, Granular stalagmite, varying in thickness from a few inches to five feet. 4. Layer of charred wood, about four inches in depth, bnt occurring in one part of the cavern only, near the entrance. This is known as the Black Band. 5. I.ight-red loam, called the Cave-earth, the actual depth of which, thronghont, is unascertained, as the examinations have been limitetl mainly to a depth of fotir feet beneath the stalagmite, 0. Crystalline stalag- mite, from three to twelve feet thick. 7, Dark-red snmly deposit quite free from limestone, in which quartz pebbles and fragments of grit are imbedded. Tliis is calletl breccia. In conveniently classifying these deposits by the animal remains found in thcin, Mr. Pengelly calls the two upper- most (which are included in Neolithic times) the Ovine period, because the sheep is never fotind below them, all the bones being those of animals still extant. The three deposits immediately below these, numbered .3, 4, and ."J in the above list, he call the llij(^nine period, lieca'use the bones of that animal predominate. The two lowest deposits he calls the Urxine period, because lx)nes only of the ca\-e- bear are found in them. Passing through the black mould, the varying contents of which lie within the province of the antiquary, we reach the uppermost layer of tJie Hyo'- nine period, the bed of granular stalagmite. Mingled with the remains of various animals, more or less extinct, as the mammoth, cave-bear, cave-hy.-cna, etc., with shells.of cockles and cuttle-fish, with charred wood and rounded pebbles ; wo find herein flint^flakes, implements, and cores, or flint- nodules from which flakes have been struck ; and, at a depth of twenty inches, a portion of a human upper jaw, containing four teeth, together with a fifth tooth lying near it. The black band, the site where the cave-men kindled their fires for cooking, or perchance for warmth and for scaring wild animals, contained about three hundred and fifty flint flakes and cores, an aV)undance of charred wood, a bone awl, bone harpoon, and needle with a well-formed eye (in the Dordogne caves the stone implements were found with which the eyes were drilled in the needles), and the remains of rhinoceros, cave hya?na, horse, ox, bear, &c. The cave-earth was richest of all in the number of stone implements, and the abundance of teeth and bones. The flint implements were of a markedly higher type than those of the Drift, and, in their variety, suggestive of cave- man's fertility of resource, as compared with his prede cessors, for the list includes well-worn stone hammers and whetstones, a bone pin, and barbed harpoons. The crys- talline stalagmite contained bones of the cave-bear only, but in the breccia, there were found, mingled with remains of that aniF.ial, implements of flint and chert, " much more rudely formed, more massive and less symmetrical in form than those obtained from the cave-earth and black band," and made, Mr. Pengelly adds, "by operating, not on flakes, but directly on nodules, of which portions of the original surface generally remain.'' Before making brief reference to content.s special to the bone-caverns of the Continent, it should l>e asked how the above l)ears out what was said in the first paper of this series concerning the enormous duration and remoteness of the ancient Stone Age. Of its remoteness we find suf ficing evidence in the deepening of the valley to the extent of between 60 and 70 ft. since man and his congeners had refuge in Kent's Hole, while the period demanded for this scooping out is itself limited when companxl with the time required for the successive deposits in the cavern, and for the intermittent interruptions which they sutlered by the streams of running water which, a.-; the layers of loam and sand, with their enclosed pebViles, show, now and again entered the cave, disturbing the older deposits. At first sight it may appear that an easy nietiiod of getting rough measure of the time iavolved in the dcposi tion of stalagmite is at hand in watching the rato at which it goes on now. But no such criterion serves u.s, because the rate at which stali\gniite accunmlates varies extremely, being determined by states of climate, by air currents, by the quantity and quality of the water, by tlie greater or lesser porosity of the rock in course of dissolution, and other causes, marked variations of rate occurring even in the same cave. " In the Ingleborough cave, in Yorkshire, it has been so swift that between 184.^ and 1S7.T a stalag- niitic l)0ss, known as the Jockey Cap, has grown at the rate of -2941 inch per annum ;' but such a rate is exceptional, as otherwise our caves would speedily have been filled up with such accretions. KNOWLEDGE [JuLv 7, 1882. That inscription (one among others) in Kent's Hole, to which reference i3 made above, does, however, lielp us somewhat in the matter. On a large boss of stalagmite, which rises from the floor, and which has been subject to the continuous drip of lime-charged water from the roof, this inscription is yet clearly to be read : " Robert Hedges, of Ireland, Feb 20, 1688." Evidence of its genuineness is at hand in the description of it left on record by the Rev. J. MacEuery, who explored the cavern in 1825. He says that "the letters are glazed over, and partly efl'aced," showing that they had not been recently cut. That description applies accurately to them now, after the lapse of sixty years. Now, the film of stalagmite over these is about one-twentieth of an inch in thickness, and the like applies to still older inscriptions, in another chamber, round the " Crypt of Dates," the genuineness of which inscriptions there is no reason to doubt. If we take as our standard of reckoning the rate at which the stalagmite has acccumulated on the Hedges boss and apply it to the bed around it, which is in places five feet thick, wo get a result as startling as it is probably excessive, because we have assumed uniform climatal con- ditions throughout True, in his notice of the last edition of Lyall's " Antiquity of Man," Mr. Alfred Wallace, an authority not given to over-estimate, remarks that the sum of half-a-million represents the years that have probably elapsed since flints of human workmanship were buried in the lowest deposits of Kent's Cavern,"* and after allowing a far more rapid rate for the formation of both the crystalline anj gra- nular stalagmites (to say nothing of intercalated deposits) than the evidence warrants, the estimate which demands the lapse of tens of thousands of years since the entombment of rude flakes in the breccia cannot be gainsaid. Some words of Mr. Prestwich, in a paper read before the Royal Society, and which Mr. Pengelly has already happily quoted, may be repeated here. He says that, "just as though ignorant of the precise height and size of a mountain range fern in the distance, we need not wait for trigono- metrical measurement to feel satisfied in our minds of the magnitude of tlie distant peaks, so with this geological epoch ; we see and know enough of it to feel how distant it is from our time, and yet we are not in a position atpre-sent to solve with accuracy the curious and interesting problem of its precise age." HOW TO GET STRONG. in.— THE CHEST (continued). A CORRESPONDENT asks how the calf-skin bag (or dumb-boxer) should be made, and how large it should l>e. There is no rigid rule as to size, or material, or make. A diBused hair pillow, doubled and tied up, will serve very welL I'ut, if you take nine or Uin spindle-shaped pieces of calfskin about •'> in. broad and from 18 in. to 2 ft. long, and Bf;w together, they will form a bag which, filled with sawdust or stuffed with hair, will be somewhat handier for Ijoxing at The exercisers for expanding the chest hitherto considered ^running, boxing, and inhaling to the full extent of the lungi) produce their efTect chiefly in an indirect manner, so far as the expansion of the chest is itself concerned, though in a very dintct manner as regards the act of breathing: the chest is made to expand because the lungs jire exf>anded, either by the deep and quickened breatliing resulting from rapid movement, or by the actual drawing in Nature, Oct. 2, 1873. of air in large quantity. We have now to consider exercises which act directly to expand the chest, and thus help the breathing apparatus indirectly, by giving it room for freer action. For this purpose all exercises are good which carry the arms well over the head, all those which carry the arms out horizontally backwards, and all those which bring the elbows close into the side with a backward motion of the shoulders and upper nr»i>!. These last words must bo specially noticed. Rowing, a capital exorcise for many purposes, is nut, as is commonly thought, a good exercise for the chest ; for though' at the finish of the stroke the elbows are drawn close in to the sides and carried back wards as far as possible, the shoulders and upper arms are kept rather forward and drawn rather towards each other, on account of the position of the hands on the oar, and also because in hard rowing no strength can be spared for a useless backward swing of the shoulders. In steady rowing for pleasure, the hands may bo set a little further apart, and the shoulders thrown well back at each stroke with great advantage, so far as the health value of the exercise is concerned. Rowing in this way is delightful, though not at all suited for racing. Beginning with chest expansion by exercises taking the arms over the head — the best exercises of all for increasing chest-capacity — we note that there are scarcely any but artificial exercises nowadays for this purpose, that is, there are scarcely any exercises which thus work the arms, as rowing, boxing, fencing, ifec, work them in other ways, or as walking and running work the legs. Climbing ropes is a rather severe form of this sort of exercise, not readily to be practised by most persons, and too severe for men past or nearing middle life, when the body is generally too heavy. The strain on the deltoid muscles tells heavily before much good has been done in the way of chest ex- pansion. There is the same defect in hanging exercises on the parallel bars, or on the trapeze. These are for athletes, and even with them, more for the strengthening of the deltoid and other special muscles than for the expansion of the chest. Rather oddly, we receive just here, through the Editor, a note from Sir Edmund Beckett, running as follows : — I do not know whctlior the writer on " How to got Stronff " will care to licar that I know no cxcreiac whinli tends so much to oxpand the cliost as bell-ringinp, being performod standing quilo upright. I used to ring tho heaviest boll in poals, at Cambridge and eleo- where, when I was young, and tho nino o'clock at St. Mary's nearly every night, and I used always to feol that result. E. B. Bell-ringing would be just the sort of exercise wanted to open the chest : for here, the hands being close together (instead of acting, as in rowing, to contract tho chest) acts — at the most cUcctivo moment — to expand it The con- struction we were about to describe for arm-above-head exercise to expand the chest, can very readily bo used to give an effect akin to that obtained in bell-ringing — which is fortunate, because only a limited portion of the com- munity can ring bells. (For 1,000,000 able-bodied men in London to get each lialf-an-hour's bell-ringing — peals of eight — per day, it would l)e necessary that there should be constant pealing from 2,600 steeples !) Let A, 15 (Fig. 1) be two pullies high up, on the same level, against one of the walls of a room, W and w two weight boxes (of course, mere weights will do) a AW, bliij} stout cords passing over tho pulley and connecting a and b, the two ends of a stout rod ab (a broom-handle will serve) to the weight boxes, W, V). Tho short cord, cd, is simply for drawing down tho rod, ah, till the upstretched arms can reach it. Now let the rod ab be grasped overhead, the arms being vertical, and therefore tho bands separated by the breadth Jolt 7, 1882. J ♦ KNOWLEDGE ♦ 69 of the chest It is best to stand with the back to the wall. Draw ab steadily down, till the hands and arms are in about the position they have just before the feather in rowing ; let the bar go steadily up again, to your full reach. Continue this exercise about five minutes, being careful to let the arms be drawn up to their full reach above the head each time. The weights at W and iv may at first only be some 10 lb. each (so that the heavier dumb- bells tied at W and io will serve very well), but can be gradually increased as the arms gain strength : though this V is not, be it noticed, the object of the exercise. For mere muscular work they might be increased until each amounted to nearly half the weight of the body ; but this would not do for work in chest expansion. In this exeicise draw in the breath fully as the bar rises, hold it till you cannot comfortably hold it much longer, then begin to draw down the bar ab slowly, breathing out slowly as you do so, and after you have drawn the bar to its lowest position — just opposite the lowest part of the breastbone — breathe out the last particle of air you can get rid of without drawing your shoulders forward. In this way you will get most benefit from each pull, so far as chest expansion is concerned. But if you want more active muscular work, expand your chest fully when the bar is at its highest, and then pull it down and let it up steadily as often as you can without letting out your breath, whicli you can finally do iu drawing the bar down, taking in a full breath as it rises again. Or you may take several pulls after cxspiring before taking in another full breath. Only note that you ought always to let inspira- tion be completed when the bar is at its highest, exspiration being completed when the bar is at its lowest. Now take advantage of Sir Edmund Beckett's useful hint. Lay hold of the cord, cd, near c, at your utmost upward reach, and pull downwards, as if ringing a heavy bell. You can continue the downward pull till tiie hands, close tog(!tlier on the rope, reach about to the alxlomen. Repeat these pulls, breathing in any one of the ways de- scribed in the last paragraph, for from five to ton minutes. You will find (we have tried it, and know*) not only • Tho reader will excnse ns for not eaying, as nsnol, Crede experto. advantage to your health, but absolute physical pleasure in this exercise. We have never taken part in bell-ringing, but wo can now very well understand how this exercise, combined with the pleasant noise of well-matched V)ell3, should have been regarded by the Puritans as a sinful recreation — somewhat only on the principle which led some one to say that the only thing wanting to make strawberry-eating perfect was that it should be forbidden. We never before thoroughly understood that passage in Bunyan's life, in which we are told that, " having been mightily addicted to ringing, he was very unwilling, for all his reformation, to leave it ; but his conscience beginning to be tender, he thought the practice thereof to be but vain, and so forced himself to leave it, yet cm! J not keep his mind from hankering after it. But then he was sur- prised with fears that possibly one of the bells might fall and kill him, so that he durst no longer go into the steeple, but would stand at the door ; and even then he was afraid Isst the steeple itself should fall upon him." Yet, says the worthy chronicler, " this was only lopping off the branches of sin while the root of unregeneracy remained." {To he continued.) PHOTOGRAPHIC SPECTRUM OF COMET (WELLS.)* By Doctor W. Hucgins, F.R.S. ON May 311 obtained a photograph of the spectrum of this comet, with an exposure of one hour and a quarter. On the same plate I took a spectrum of a Urs.'B Majoris for comparison. The comet's spectrum on the plate consists of a strong continuous spectrum extending from about F to a little beyond H. I am not able to distinguish any of the Fraunhofer lines in this continuous spectrum. The slit was rather more open than was the case in photographing the spectrum of the comet of last year ; this would make these lines less distinct, but the lines G and H are well seen in the star's spectrum taken under the same conditions. We may therefore conclude that the part of the comet's original light which gives a continuous spectrum is much stronger relatively to the reflected solar light in this comet, than was tho case in the comet of last year, and for this reason the Fraunhofer lines are not distinguishable. Observations of tho visible spectrum had already shown that the comet diflcrs remarkably from the hydrocarbon type common to all the comets, some twenty, which have appeared since spectrum analysis has been applied to these bodies. The photographic spectrum shows, as was to be ex- pected, that this essential dilFerence of spectrum exists also in the more refrangible region. The very strong ultra- violet group assigned to cyanogen is not to bo sivn on the plate, and the bright groups between CJ and /», and between A and II do not appear to be present. • Substance of note rood before the Bojal Sooiety, Jnno 16, 1883. 90 • KNO\VLEDGE ♦ [July Tlu- liiiul of the comet wixs in sharp focus upon the slit, aiul the coutiiiuous spectrum with - taining an introduction from a Fellow. Provincial libraries are, almost without exception, extremely deficient in geo- logical works. Even the volumes of the Pala?ontographical Society, in which all the British fossils are Uing figured and described, are hardly to be met with on the bhelves of one public library out of ten ! Of the " Transactions " and other publications of the local scientific societies of Great Britain, I do not believe there is a complete set in any library whatsoever. But, besides the study of specimens at home, tliere is much geology which can only be learnt by looking at the rocks on a grand scale in the field. It was said of Mur- chison that " he had a fine eye for a countrj-,'' and it is the acquisition of this power of reading the surface features of any landscape that we should strive to obtain. No district can be uninteresting, or can fail to furnish useful employ- ment to a true geologist The pleasure of understanding the causes which have produced our English scenery doubles the delight arising from its contemplation, and when, after viewing the rocks from a distance, we interro gate them closely in the quarry or on the hillside, we shall learn from them the hi.stor\- of the past, told without possi bility of error, and with a fulness according to our powers of interpretation. EXCxLISH SEASIDE HEALTH-RESORTS. By Alfred Haviljlxd, MR.C.S., F.R.M.C.S. Lond. CLASSIFICATION" (Conlimud from page .53). BEFORE leaving the subject of the effect of latitude on the climate of the sea-coast, it will be well to refer to an opinion entertained by many against the more northerly health-resorts. It is supposed that because they are so many miles north of London and other large towns, that they necessarily must be cold, exposed, and unfitteurpose, as to the relative proportion of land to sea that obtains within each zona Such an area, if the width at the northeni Iwundnry \>e made equal to the southern, instead of following the 92 KNOWLEDGE [JoLY 7, 1882. mpriiliiuis (wbich grow closer to each other as they approach tlio north) would represent about 137,4 14 square Enjjlish miles ; each zone would therefore contain about 2l',907 square Englislj miles. The distances between the parallels of latitude are longer than at the equator. The average, however, of G9i Engli.sh miles has been taken, and this would give in round niiuiV>ers 23,000 square English miles to each zone. We shall now be able to estimate the pro- portion of land and wator within each zonal area. laUrisUtodiBil Zone*. Number of BngUASqu ■re Miles of Und. S<-a. Zone. LMd. 8e.. III. IV. V. VI. 6C"-55»N. 55°-54'' 5l°-53* 53°-53° 52°-61° 5l°-50* 8,750* y.ioot 9,450 18,500 15,600 6,550 14,250 15,'.00 13,550 4,500 7,400 16,450 23,000 23,000 23,000 23.000 23,000 23,000 380 30-8 410 804 67-8 28-9 020 69-2 590 190 32-2 711 i 05,950 72.050 138,000 47-7 52-3 * SootUnd 6,900 and BngUod 1,830 B.m. t Bcotlud 730 and EngUnd 6, 130 s.m. The above figures will demonstrate the remarkable difference that e.xists between the several zones into which the area has been divided. The percentage columns show that the whole area has more sea than land ; that l>ctween the IV. and V. zones there is to be found the greatest amount of land; that the most southern (VI.), and one of the most northern (II.) have the most perfect insular character, and that the four central zones difTcr widely ; for instance, the two northern zones II. and III. have an immediate sea area of 29,450 square n)iles, whilst the two below them, IV. and V., have only an immediate sea area of 11,900 square miles. This large additional amount of sea suiface, close to the north-eastern and north- ■western coasts, which, between these parallels, are nearer to i-ach other than at any part of the east and west coa.st lines, has a powerful influence not only on the climate of the coast, but on that of the interior ; this influence is more evident during the periods of extreme heat and cold, as in January and July, when the weak most require it. In the winter, when the Gulf Stream tempers our climate, the.se, as it were, extra 1 7, •").')0 square miles of sea, bring closer home its warmth, and in tliis way reduce the daily range of temperature. In the summer, the small area of land lying between tlio two seas has its sun heat cooled by them, 80 that an insular climate becomes as perfect in the north as it is found to be in the south. Many of the above facts, now that they have been given in detail, may bo rendered still more evident to the eye by means of chart diagrams, with one of which we hope to illustrate, next week, some of the points dwelt upon in former pages. The six zonal areas we have thus de.scribed will serve our purpose admirably for grouping together our Hc;aside Health Resorts ; for each belt of land and .sea has its characteristic climate factors, and each its physical peculiarities; each its distinctive surroundings; and we sliall see how these operatf; in producing that variety in our climate which has rendered it so diflfi .ult a study. We shall have, in the next place, to consider the position of the Seaside IlealthResorts on the seaboard, and point out how their climates are affected by the Gulf Stream, the North Sea, and the Continent of Europe. Ki.Fi.TKir Ur.m IN A Salt Mink.— Thr; Witton ITiill Salt Minoir WamDjftonroad, Northwlcli, in now lij^hlcl up by Brunh lf»mp« ir p\hre of tho candlos gcnerftll/ luxxl. Thero are Bixtoon Uri^n on lamjiii ciDjiloyod. FUTURE SOURCKS OF OUR FOOD SUPPLY. By Percy IIussei.l. AUSTRALASIA. AT a time when, as a nation, we are becoming increas- ingly dependent on foreign supplies for our " daily bread," and when there seems no prospect whatever of the home producer again meeting in any adequate degree the ■wants of the home consumer, it is surely equally profitable and interesting to inquire into the nature and extent of the resources beyond the seas which exist for the due pro- visioning of these over-peopled isl.ands. In truth, the national commis.^ariat has important social and even political bearings which appear to bo unduly slighted by many among us, while in its industrial and commercial aspects it is obviously of transcendant impor- tance. Most persons are aware, as a mere matter of general information, that we now draw a great portion of our bread stud's from the Ignited States, and it is known, too, that many items of dairy produce reach us from the same source, while France furnishes us with no inconsiderable part of the fruit and vegetables which might, in a great many cases, b(! grown by ourselves. In ed'ect the British islands are now, to a certain extent, regularly victualled from extraneous sources, and as the requirements of a people who are ever becoming more and more concentrated in towns and cities, constantly augment, the food importer is over on the look out for new fields whence he may draw his enormous supplies, and thus, by introducing fresli factors into the commercial calcula- tion, defeat the designs of those who look to monopoly for forcing up prices. Enough has been written about the vast wheat-fields of America, and the great resources of Canada and the west of our North-American dominions, but I do not think that persons hero not directly connected with our Austral- asian colonies have any adequate notion of their real capa- bilities for provisioning this country, or of the happy and mutually beneficial result that must ensue from a more complete interdependence of these islands and the great Austral continents. I propose in this paper to give a rapid sketch of Austral- asia as a sufficient source in the future for all such food staples as we may need, and to show by facts and figures that in settling these remote regions of the southern hemi- sphere, we have unconsciously obtained a safeguard against the very possible and appalling peril of any combination that might bo efl'ccted in the United States for the purpose of extorting ruinous rates on account of our evident inability to supply our own people with food. On the one hand we have within tlic; contracted area of these islands a population of soiiu'tliing like 40,000,000 all told, cultivating about 3,000,000 acn^s for wheat, and ownini:, in round numbers, 10,000,000 head of cattle, 27,000,000 of sheep, and 3,000,000 of pigs, and having a trade valued at about £097,000,000. On the other hand we have an area, some 3,000,000 square miles, i.e., twenty-six times the size of (ireat Britain, occupied by a (lopulation of le.ss than 3,000,000, raising, on an average, nearly 40,000,000 bu.shels of wheat, possessing over 8,000,000 of cattle, 7.^),000,000 of Kheej., and 1,000,000 of pigs, while the aggregate trade of this community — rich in corn and cattle up to scriptural standards — amounts to close on £100,000,000 per annum! If we carefully compare, then, the outcome in material w(!ll-being and in diffused general wealth, of the scanty Australasian com- Jdly 7, 1882.] ♦ KNOWLEDGE ♦ 93 muuities with our own over-populated country, wc cannot fail to be struck by the marvellous way in which, at the antipodes, production has outstripped population and given to progress a true cornucopia running over with an abundance of the good things of this life. Clearly between two such communities reciprocity should exist in the fullest and most generous sense of the expres- sion, and thanks to many happy causes, among which the great acceleration in steam navigation is one of the chief items, this reciprocity does exist in a large degree, and unless our statesmen, in dealing with these nature- favoured colonies, commit some extraordinary tiscal or political blunders, we may fully rely in the future on the readiness and ability of our Australian cousins to make good the shortcomings of our corn-fields, our stock- yards, our sheep-lolds, and even of our orchards. Let us examine in detail, then, the true character and extent of these Australasian resources in all their home- bearing aspects. Turning to the parent colony, New South Wales, we find that the total area includes 198,626,143 acres, or, in other words, it is about the size of England and France combined. It is within bounds to assert that everything produced in England can be grown in new South Wah's, including^besides the familiar fruits of the temperate zone — oranges, lemons, tigs, ic. During the latest year for which we have comprehensive statistics, 252,540 acres were under wheat, yielding nearly 4,000,000 of bushels, while over 50,000 tons of good potatoes were also raised, to say nothing of oats, barley, rye, sugar, and grapes, which last gave 584,000 gallons of excellent wine and 6,600 gallons of good brandy. This is, however, not all. There were, at the period in question, 706,498 acres under cultivation, and no less than 21,351,4.33 enclosed ready for agricultural operations, while some 6,000,000 acres lay outside ready to be brought within the productive pale. The stock returns were no less remarkable. SVe find that there were on March 31,1881, of horses 395,984 ; of horned cattle 2,580,040 ; of sheep 32,399,547 ; and of pigs 308,205. Such were the resources, roughly speaking, in bread, beef, and mutton of only a single member of the great Australasian group, and at the date in question the population, all told, was but 503,981 souls. The figures relative to the live stock resources are of great moment, for the requirements of Great Britain in the way of butcher's meat are computed to reach over 600,000 tons per annum, a quantity coEstaniiy increasing, be it observed It is gene- rally admitted thati n England the meat consumption per head is full 1201b. per annum, and it is well known that we do not ourselves produce 80 lb. of this amount The difl'erence has, therefore, to be made good from alien sources. To till up the deficiency requires full 20,000,000 of sheep, and here we find that a single colony — New South Wales — can very nearly accomplish this tremendous commissariat feat unaided, and still feed her own people. New South Wales, however, is by no means Australasia, as wo shall presently perceive. Let us now turn to the most highly civilised and, to borrow an apt scientific phrase, differentiated of all the Australasian communities — Victoria. TiiF. jABLOcnKOFP LiGiiT.— Tlio contrnrt for illiiininntiiiK llio Avenuo do I'Opi'ra with tlio Jabloclikoff candles has been renewed by tlio mnnici()nlity of Paris for three years. Power has been Rrantod, in connection with this now contract, to introduce the light into the houses in the district. Wateb Power AMD the Ef-ectric Licnr. — It is rnmonrod that n wealthy company is maVinf; arrangements to bny the water power at Harper's Ferry, on the Upper Potonino river, witli a view of lighting Washington city and Baltimoro by the electric b'ght. 3^tbit\3)i, SHAKESPEARE STUDIES.* EVERY Englishman ought to study Shakespeare till, as far as in him lies, he knows him well. When certain passages not corresponding with our present ideas are omitted, the same may be said for every woman, and for the young folks, too. We want Shakespearean teachers for such study : so that the splendour of Shakespeare's gift to his people and to the world, to his age and to all time, may be rightly seen, while yet the spots on that splendid sun may be recognised also. But, thus far, most of our teachers — nearly all of this present day — are word-carpers, metre-measurers, comma-counters, allusion-hunters, and antiquarian note-gatherers. They do good service in their own way, but it is not the kind of service which is chiefly wanted. It is interesting to know that the poet we have learned to love as Shakespeare spelt his own name Shakspere, and probably pronounced it Shax-per ; to learn that in " Love's Labour's Lost " the proportion of unstopt to end-stopt lines is 1 in 18-1432 ±, while in "The Winter's Tale" this proportion has sunk to 1 in 21214 ± ("Bless thee. Bottom!"), and to learn the numbers and percentages of light-endings, of weak- endings, of verse lines, and so forth (" God bless us, a thing of naught!"), and to classify the plays into Life-Plea Plays, Unfit-Nature or Under-Burden-Failing Plays, Ingratitude and Cursing Plays, and Plays of Reconciliation and Forgiveness.t But "when all is done," this is not studying Shakespeare, any more than measuring star-places is studying astronomy, or counting the colours in a noble painting is studying art Even the attempt to recognise from the style what Shakespeare really has or has not written, in works attributed to him, or what he has written when at his 1>est or not so well, is of little real worth compared with the loving study of his grand creations. Loving, yet not unthoughtful. We would not see Shakespearean students accepting all that he has left us, as if it were beyond criticism. There is scarcely a play of his whose plot is without fault or blemish, and in many of the finest the borrowed story, which not only forms the groundwork of the plot, but is left to form tlie plot itself, is absurd, and sometimes even monstrous. Those who try, in their love for the poet, to defend or to praise Trhit ir«= no pirt o£ his ^ork (tho^igh he «-s3 in fault for not rejecting t), n tea ity fail to understand him, and do his fame illservice. Claudio's light-hearted acceptance of Hero's cousin, Bertram's sudden resolve to love Helena "ever, ever dearly," the Duke's "Your evil quits you well" to Angelo (murderer in intent), Valentine's "All that was mine in Sylvia I give thee," and hundreds of such flaws, belonged as certainly to the original story as Cscsar's A'< III L'nite ! If we take them as Shakespeare's we mar his work. Nor can any thoughtful reader fail to see in his earlier writings the signs of weakness and bad ta.<.te, — the weakness that of inexperience, the bad taste not his own, but that of his age and surroundings. It is only by separating these imperfections from his true and matured work that we can rightly and lovingly appreciate the greatest poet the world has known. The edition before us is not injured by the petty talk of letter- and line-counters, date-hunters, and the like, for no • " Tlie Leopold Shnksporo." Messrs. Casscll, Pt-tler, A Golpin, London. t If there is one IhinR more than anolhor wliioh ronld mnrk a man ns thoronRhly nnnblo to rei>i);nifO the trno >-aI«o of Shake- Kjienro's gift to man. it is snch nn atlenipt (efore had begun to lie felt rather painfully by him. He liad learned the lesson which he taught a year or two later : — Let still tlio woman tako All filler than lier.wlf ; so wears she to liiiii, So sways she level to ber liiLaband's heart. Also, it is to be feared, tliis other lesson, that. However we do praise ourselves, Our fancies arc more giddy and infirm, More long^ing, wavering, sooner lost and worn, Than women's arc. (At least, when the woman Ls much the elder.) It is no unfair assumption to suppose that in Adriana, Shakespeare pictured the erst fair Ann Hathaway; in .\ntipholus of Ephesus himself. (It would be sacrilege to think thus of any characters in his later and greater plays). • It is rather sin^lar that in "Titus Andronicas" and the First I'art of " Ilcniy VI.," both of which contain passages utterly atro- rh.un ill Style and treatment, insomuch that some question whether > , ik.-^|*.in- wrote a lino of cither, both contain lines so similar to ■ ,:;.i- 111 ]Ai earlier sonnets as to leave little doubt that they canio iruiM iho same pen. Thus, compare " Titug Andronicus," act ii., scene 2 : — " 8ho is a woman, therefore may be woo'd ; Shu ia a woman, therefore may be won." And " Uenrr VI. ," Part I., act v., scene 3 — " 8he 'a beantiful, and therefore to bo woo'd ; She is a woman, therefore to be won." Wiih thcso lines in the forty-first sonnet : — " Beauteous thou art, therefore to be nssail'd ; Gentle thou art, and therefore to be won." Perhaps, however, some tcn-s}-|lablo proverbs familiar in Bhake- Hpearo's time may have l>cen quoted, or referred to, in all thcso putmges. + --■•.niiiria'i wtia his first-bom. Mr. Furnivall's acconat of rly love is rather exceptionally absurd, llo is Iniit tluit if Shakespeare was a "young stupid," ■! of us; and telling us that one day Anno and '■'■' ' more," he kindly explains " that is IJanto's," as if tl- 1 ,-,< , . f Krancesca de Himini and Paolo were not known to all. Possibly ho may have meant the Abbess's rather severe teaching for his wife's special benefit : — Ills meat was sauced by thy upbraidings : Unquiet meals mako ill digestions; 11 is sports were hinder'd by thy brawls : Sweet i-ccrcation barr'd, what doth ensue But moody and dull melancholy, Kinsman to grim and comfortless despair ? &c. The other play in this first part is " Henry VI,," Part II., little better than Part I. All illustrations to Shakespeare are " an abomination of desolation," from Sir John Ciilbert's, Harvey's, and the like, down to those illustrating Dick's " Penny Shakespeare." Those in the present edition are among the worst we have seen. Before issuing an illustrated Shakespeare, publishers should wait till they can engage an artist as great in his own line as Shakespeare in his, — and /fioi they should be assured that their artist understood Sliakespeare. A NEW GUIDE TO THE ALPS.* TiiK season of Continental travel has come, and guidc- liooks arc in request. Murray and Baedeker are dear, and they overlook sometimes the minor wants of travellers. They address their readers as though already experienced travellers. The guide before us is very cheap (half-a- crown cannot be called a large price for a book of more than 400 pages, with many elaborate maps atul diagrams, and crowded with information on all sorts of topics im- portant to tra^■ellers). If we do not altogether admit the scientific accuracy of the description "indispensable," which occupies a whole page at the beginning of the book, we must admit that a work such as this claims to be, is, at the price, a very desirable addition to the contents of the tourist's wallet It treats of Switzerland and the Swiss, and Alpine auimal.s and vege- tation, gives hints to tourists, discusses the various routes of travel, and deals in special articles with hotels and pensions, mountaineering, what to wear, glaciers, Swiss butterflies and moths, avalanches, baths and springs, the Alps generally, the Upper Valais, the Bernese Oberland, the Italian Lakes, and many other subjects too numerous to mention. Some; omissions should be corrected in later editions. The carriage-roads over the Ober Alp should have been shown in the general map, while the railway under the Lukmanier should have been omitted. We note also the entire omission of the Gries Pass. Monte Gtuieroso and the Ilieder Alp afl'ord good rest for the weary, not men- tioned in the "J. E. M. Guide." Such omissions, however, though they might be noteworthy in an old established Guide, may well be excused in a new one. Amon(;st the many electrical companies started during tlio past few days is one for working a material called insulitc. It is intended to be used as an insulator, superseding glazed porcelain, ebonite, Ac, and is composed of sawdust and suchlike substances, held together by oxokerit. In the prospectus, it is stated that the material has been supplied to the General Post Office and a number of electrical authorities. So far, however, as our informa- tion goes, the Post Office has only had a few specimens for trial. On subjecting the insulito to a moderate temperature, it expanded like so much dough, and crumbled to pieces between the fingers. It is, moreover, incapable of taking small screws. Under those circumstances, telegraph insulator manufacturers and ebonite merchants need fear littlo from this substance, which has been brought out with such a blaze of trumpets. • "The Alps, and Uow to See thorn: the J. K. M. Guide to Switzerland." Kditcd by J. K. MudUoek. (Sirnjikin, Marshall, & Co. ; Wyman 4 Sons, London.) July 7, 1882.] • KNOWLEDGE • 95 TRICYCLE RIDIXG FOR LADIES.* THE opinions of society, at least English society, are changing, not slowly and surely, but quickly and surely, as to what women may or may not do. This is observable more especially in the matter of sports. Hardly any athletic game is now brought fonvard but women can take part in 'it with men, if they please. And let me say this is a privilege and a benefit to both men and women, for nothing is more healthful to both than their joining together in their amusements. Men have a great respect for those, be they whom they may, who can play a good game with them. It produces a kindly, hearty feeling ; and when called forth by women, brings with it the addition of a •chivalric honesty. He really does wish to give her a " fair field," while she really does wish to receive " no favour." This was very pleasantly shown in a lawn tennis match which Major Wingfield (who introduced lawn tennis to the English public) and a lady, some little time ago. The lady proved such a formidable opponent, that he declared that he had the greatest difficulty in beating her, and that if she had not been unduly handicapped by the weight of her dress, the issue of the game would, no doubt, have been different. To test the truth of his conclusions, he begged that the lady might have her clothes weighed, while he would also have his ■weighed. His were found to weigh -ti lb., while hers weighed 10 lb. This disproportion of weight to carry, as any one acquainted with sport " well knows, is enough to make either man or horse lose a race. In a similar way women allow themselves to be over-weighted throughout the whole of their lives, whether at work or at In the matter of "play," tricycle riding affords another very striking example. Nothing in modem times which has been offered them can be reckoned a greater boon. Something to vary the etual sauntering along the same streets, gazing vacantly into the same shop windows. The Sanitary Record for this month has a short article recom- mending tricycles to its readers. It says : — " Tricycles have over bicycles the great advantage that they .ire suited to every age, to both sexes, and the most varied physical conditions. Every one in ♦•rdinary health, and possessing the use of his limbs, can, without offort, and without previous instruction, learn to ride a tricycle. Very little practice enables the tricyclist to traverse considerable ■•listances with ease, comfort, and safety, and at a very adequate and satisfactory pace. A pace of from seven to ten miles per hour is •easily attained on the tricycle, and maintained for several hours in succession without effort. The exercise is distinctly healthful, and the mere rapid motion through the air is of itself invigorating and refreshing. Moreover, it is so much more pleasurable to many than the slower exercise of walking, and the facilities for covering an ■extent of ground and getting quickly out into the countrj-, or the most pleasant suburbs of great cities, are so great, that we cannot too strongly recommend our readers generally to try for thercselvcs the advantages of the tricycle." But here, again, women's clothes are a hindrance and impedi- ment—a constant and unnecessary tax upon their strength and -endurance. It is not in this case, as in la^vn tenrus, the li/ling weight of them which tells, but the resiiting weight. The Sanitary RecorO says, <-vcryone " possessing the use of his limbs " can learn to rido a tricycle, but can a woman tied up in petticoats be said to possess the use of her lim'js f Every time she lifts her legs to move the treadles they have to encounter, resist, and battle with the weight of the overhanging skirts, while in going against the wind tliey offer about four times as much resistance as the man's trousers, and every tricycle rider knows how that extra labour tells in working the machine. Moreover, the really unprotected, unclothed con- • lition of the lower part of a woman's body requires that the -Teater part of her attention and efforts should bo directed towards ;i feuding herself against ridiculous and indecent exposure. Women naturally sensitive on these points hold aloof from attempting tricycle riding on this account, and will continue to do so till a more suitable and safe garment is provided for them. A lady who is now a member of our Rational Dress Society wrote to mo from Scotland, asking for a pattern of our divided skirt. She said that ladies in her part of the country had to drive about a good erfect insects. When hunting for egg-», a few shallow boxes made of thin wood or card-board should be taken, in which the eggs can be carried home. A very careful search among the leaves (especially the under sides) and twigs of trees, stalks, and leaves of grasses, fences, and numberless other places will probably yield good results, and the leaf or twig should bo cut off and placed in one of the Wforc- mentioned boxes, as by this means they will not become broken by touching one another. If the eggs are attached to a wooden fence or railinir. the piece on which they are deposited must, if possible, be carefully cut away with them, as scra])ing or brushing off mujt ncrcr bo attompteti, owing to the exceedingly fragile nature of the i xtenial covering membrane. Also take notice what trees are in the immediate vicinity, as one of them will in all probability form the foo«l of the future caterpillar. When the eggs are taken home, place flicra in a shallow box without a lid, carefully noting down particulars about each hatch of eggs— such as timo'of year and where found, whether laid singly or in clusters, and any other circumstance connecte| miles, t ifth dav. Horsham, Crnwlcv. Krigate, Cn.ydon. Strcatham, Bnxton, Wistminstor Bridge, Th.unes Embankment to llolU-rn Niaduct, ■Wi miles, .\vomge, 17 oiM miles a day ; luggage carried, over two stone. Lovely weather, ditto scenery, and most enjoyable fatigue- less ride— Ex'-BicvcLisT. f6 KNOWLEDGE • [July 7, 18S2. WEATHER CHARTS FOR WEEK ENDING SUNDAY, JULY 2, MONHAY, "20X11. W] DXESDAT, USTn. TnoRSDAY, 29tu. Fkiday, 30tii. Saturday, Ist. Sunday, 2kd. In tho aliove charts the dotted lines aro " JBobnrs," or lines of eqnal barometrical pressure', the values ■nhicli they indicate being gircn in fi).'ure8 at the end, thus — 30'4. Tlio shade temperature is given in tigures for several places on the coast, and the weather is recorded in words. Tho arrows fly with the wind, the force of which is shown by tho number of barbs and feathers, thus:— *~ light ; > , fresh or strong ; y j , a gale ; » > , a violent gale ; O signiSes calm. The state of the sea is noted in capital letters. The * denotes the variona stations. The hour for which each chart is drawn is 6 p.m. FORESTS AND RAILROADS. FROM an otTicial report made on American railroads, wo have ("imc corimis fa/ts relating to the direct connection between tlic railroadi and tl.e deforestation of tho United States. From it we learn that it takes 201,000 acres of forests to supply cross ties for tho rxilrmds of the United States every year. It takes l.S,CiOfi,0<'0 ties to supply tho demand on these railroads, for which ',n an averniro the contractors get .tS cents apiece, making in tho ai'gregatc 5,250.h, and even loc-ust have been LS-yl. The la.Ht nomod| were first used on tho little Miami rail- roa/l, and after a time thrown aside as unfit for the purpose. Railroad mi n much prefer tics hewn oat with an a«o to thoso •awn in a mill, and many contend that tho first-named will considerably outlast the sawed ties. This theory is probably a fallacy, as sawed ties have been placed alongsi.] THE "Cur.D SXAP" IX JUNE. [455] — I have read a good deal in K.nowifdge about the cold week in May, and have seen M. de Fonvillc's asteroidal theory exploded mo^t thomnghly, and, as I think that the nlmormnl tem- perature of lUth — 12th June was as much (r more marked than the three days of May, 1 beg to suggest that the cause I'f the same may bo fonnd in the enormous diameter of the cyclone, and the slow movement of its centre, which encompassed ns, and the posi- tion in it, in which we were placed at that period. It must have been at least 2,< 00 miles in diameter. If upon your weather chart we trace back the isobar curve, which is nearly alwnys coincident with the direction of the wind, to tho distance of the quadrant of a circle, we shall find that the air which wo received must have been, only two or three days before, driving over immense tracts of ice-bonnd mountainous cnnntry, even beyond the arctic circle in Norway and liussia, and no doubt driving herds of icebergs into the Atlantic. We know that air is not warmed directly by tho sun, but by contact with, and radiation from, a warm surface — generally land ; that air cannot be warmed appreciably above 32° whero fnow exists, and that only a email rise of temperature can take pinco in passage over water; therefore, in this position, we receive tho cold blasts at a temperature very little above what they left these wintry regions at. I think in this also may bo fonnd the difagreeablenesi of thn N.E. wind— tho cold air travelling over our warmer lands has ki« point of saturation so suddenly raised, that it wrings the moistoni out of everything, fairly burns up vegetation, and produces that unpleasant feeling in the skin (really a dryness) su well known during these winds. It may lo advanced aga'iijst this that it very often rains from the N.E. 1 should say that on such cccasions it must have started from the far north raining much heavier, aad is decreasing all the way south. At such times, owing to the moisture present, the objuctiouablo feeling of the skin is not apparent. if this theory be correct, wo should always experience Encl» weather upon the back of a large, well-develo[»ed cyclone, or upciii the front of an anticyclone, when the centre, travelling slowly from W. 10 E., passes to the north of us. J. Moksin. CONSUMPTION. [456] — Allow me to cffer a few hints which do not agree with Koch's germ origin of phthisis. There are a few wril-kiiown kindx of consumption, known asthe knife-orscisfor-griiders', the mineis' or marble-masons', and the cotton-sorters'. In all these cases the disease is duo to bieathii g troall particles of iron, coal, stone, or cotton. These particles are carried into minute tubules of the lungs, and there set up irritation and int!ammation by tl eir presence. The sputa of these patients contain iron, coal, or stoni- particles. There is also another kind cf consumption which docB not come under Koch's theory, and that is fibroid consumption, duv to excessive drinking of alcoholic liquids. Consumption is caused by anything whiih tends to wcakin the body, amongst which im- pure air may be set down as a great cause. Many of the present generation are carrying tie germ theory t<» excess. Many medical men are afraid t f geinis as if they wen- poison, and will not allow a simple wound to hial without applyii'it some germicide. The healthy body is the best known antidote to germs ; a germ cannot flourish there ; it is like throwing seed on :» rock — it soon |erishes. [But if the body ia unfortunately n'jt healthy ? — Ed.] — Voors truly, June 24. 18t>2. T. K. Allinsox, L.R.C.P., Ac. BREAK FOR TWO-WHEELED VEHICLE. [457] — Malvern town abounds in steep hills. The two-whecKJ vehicles, from the doctor's gig to the butchers' and bakers' carls, have double breaks, i.e., one to each wheel, actuated by a lever similar in construction to that used on four-wheeled vehicles, applivd to the back of the wheels, in a line level with the axle. U. U. Hay 2f>, 1SS2. FIELD EMETICS. [458] — " As a practical thing to know (in the field), a rbargo <>i gunpowder is a capital emetic — tiu it (in eirjort t-Wi)." — (lid- Knowlei:cf, vol. ii., p. 8). Query— Would cot dolrmite, «1 aken up with water (it wou.d not dissolve), often be of value, on acccuut of the carbonate ol magnesia ? M. TRICYCLINO. [459] — Probably, many of your readers may be seriously thinkirf; of procuring a tricycle, and securing exercise and change of eceni» by that most excellent and delightful means. lo such as may be that way inclined, n few words of advice as t<» adjustments, accessories, Ac, from a prac'ised cyclist may, perhaps, be useful. I mentioned in my last letter the machine and siio of wheels I have found to give me the most satisfaction, and will merely now say that, whatever may be the machine selectiil, it thovid drtre hoth uhet'U dirrct, without any complications, 1 lit* with simple chain* with revolving ferules < n the links. 'Ihf»«' «ill le fonnd to hf much more reliable than anything else, in spite t f objections in theory that may be urged to the onlrary. 1 haw ridden luy mBchini» some 4,lK)U measured miles since last Jnm-, and never yet had any trouble whatever «ith tho chains. My atlvice is, s|x^i»lly avoid all complicated mechanism, as it is snre lo ;;o wrong before long when put to tho inc^^s:lnt jurnng of the roads, cr to make an irritating, rattling noise. With a large wheel, a weak rider can snurc great ease of work ing by " gearing down," i.e., by having his top rog-«hrels with mc8 incrca>cd power b)> hills, though, if carried to excess, it much decreases the spted. All who wear tnaisers should ride u| on saddles — not seats. .\ saddle allows the legs to hang ficcly don nwardf, and to work witlioal 98 KNOW^LEDGE [JuiY 7, 1882. rfstraint from the hip. Ami though in tho shop it may seem that « •• scat " ia much easier whcu used as one might use au onlinnry chair, and sat " siiuub " U|>oii, when ritling this cannot bo done, and at tho same time permit the legs to move from tho hips (ag in «Talking>, which is a sine <]iiti noii for comfort in riding. A man on a seat must have his legs bent at an acwto angle at the knocs, and he then presents a Tery unsightly appearance, with his kucos iioji- ping up and down almost up to his chin, besides the extra fatigue invoh-cd. Saddles arc made with a broad seat, and also with backs, and they are really most comfortable, and tho pommel so divides the fork as to avoid all dialing. Ex-Bicyclist. [460] — It may interest those of your readers who arc trioyclists to loam that Mr. Marriott, of Nottingham, has ridden from Derby to Uolyhcad, through Burton, Lichfield, Shifnal, Shrewsbury, Corwon, Bettw8-y-Coed, and Bangor, a distance of one hundred and eighty miles, in iwenty-threo hours and three cjnarters on a tricycle. Tho road for quite half the distance was mountainous, .some of tho hills being six and scren miles long, and in many parts tho roads were so rough that it was like riding through the bed of a stream dried up. For a tricyclist. this is the longest journey in twenty-four hoars on record. Jon.v Bh6w.ni.so, L.T.C. INFLUENCE OF CLIMATE ON PLANTS. [461] — In a number of Kxowledoe on which I cannot at present lay my hand, I noticed some facts with regard to the influence of climate on plant.". It way interest your readers to know that plants foci severely the change in their usual habits which takes place when they are transplanted from Europe to South Africa. Tho Curator of tho Botanical Gardens here, who has, perhaps, more practical knowledge of tree-planting than any man in tho country, informs me that this is markedly the case with regard to fruit- trees. The reversal of the season.'), occasioned by tho change of l:emispherc, bewilders tho plants, which are in some sense " edu- cated " to such a degree that they arc not able to survive the shock. Tho only chance of getting them to grow is by grafting, when they borrow tho constitution of tho tree on which they are grafted, and acclimatise readily. Ordinary deciduous trees bohavo very ii-rc- gularly also. Sumctimes they will pull through, sometimos they die, but the first i uttings never appear to thrive. I understand that evergreens are not affected. Birds take to tho change of season well, if one may judge by the few European sparrows which have beeri introduced. European dogs generally die. Imported oxen and horses appear to do well, provided they receive tho same amount of care which they expe- rience at home. Cats thrive. Perhaps I may bo pardoned if I suggest that tho appearance of nnmerous articles from upholders of Darwinism in your capital magazine, must not lead your less scientific readers to imply that Darwinism is by any means universally accepted. It is, admittedly, only a hypothesis. 1 use tho word hypothesis in tho sense to which yon restrict it in " Pleasant Ways in Science " (p. 315), as an opinion not based on phenomena. Dr. Mivart, one of tho greatest of living anatomists, terms it, with all due solemnity, " a jmerilo hypothesis." May I be allowed to recommend to those of your readers, who are not terrified by mero weiglit of names on the other side to road care- fully Mivart on the ' Genesis of Spcnies," Dr. Elam's " Winds of Doctrine," and Dr. Beale's " Protoplasm," in which they will find refreshing antidotes to the works of Danvin, Iluxley, and Uacckel, the positive, comparative, and superlative exponents respectively of the faiihionablo doctrines in trancendental doctrine. Especially let them study well the history of " Batbybius Uaockelii," two unfit evolutions from tho original Darwinic idea, which have ceased to survive. As a last suggestion (1 hope yon will forgive the space) moy I remark that your magazine is extensively read this side the equator, and that some good map.i of tho southern sky would bo appreciated both here and in Australasia. j! Nixox. Omhamstown, Cape Colony, ilmj i, J882. THE SPAWN OF " DOIUS TUBEHCULATA" (COV.). [462] — I have lately obtained a largo mass of the riband spawn of tho largo Nudiliriinoliiato Mollusc, Dnria tubeyeulata, which, I think, worth mentioning in your columns. While on a visit last week with a relative at West Kirby, near Iloylake, Cheshire, I availed myself of the oji|)ortunity which a tide of about 18 ft. fTordcd, of a visit to the Uilbrc inland, at tho month of tho Dec. ■I;ivingon a previous occasirm been fortunate enough to secure vemi fine sfiecimcns of tho beautiful Dcndronotiiit arliorc/ccnii, 1 ' ioaght I would trj- my luck again. I may mention that Ililbro i-ilaotl during tho tides of the spring and aotamn equinoxes is well worth visiting for specimens of marine zoology. Tho tides of last week, however, were not sutficiontly low to expose at their full ebb tho most promising places. At one spot 1 CBi>iod a largo white mass of something hanging from a rock, and this I found to bo tho riband spawn of Doris tiihciculata ; it was hanging from tho undcr- lodge of a rock of red sandstone, to which it was firmly fixed, except nt one end of the mass, where, for about three or four inches, it hung loosely from tho rest. On detaching tho mass and unfolding it, I was astonished at its great length. 1 did not measure it, but 1 am sure lliat it was more than a mile long, and being in one uniform, uninterruptod band, it must have been tho product of a single parent. Tho breadth of tho band I afterwards found to measure one inch and four-tenths. Not far from this spot, a Iloylake fisherman, who was after prawns, scooped out in his net from under the ledges of the rock two creatures, which ho politely gave to me ; these were two fine specimens of the Nudibranch itself. The largest, which was of a beautiful lemon colour, without a single spot of any other colour, measures — for I have both specimens alive now — four inches in length and two-and- a-half in breadth. Tho other is not so largo, and is handsomely marbled with yellow, dark brown, and delicate pink. I do not know whether this spawn-mass is of unusual size, but Alder and Hancock speak of an unfolded coil of Doris spawn of nine inches in Irnf^'tli and nearly ono inch broad as being ono of lai-go size. .Spieiniens of Vuris tuherculula have been found measuring five inches in length ; I should tliink that tho parent of the mass I found must liavo been larger; for the riband must have been fully forty inches long. This band, which is transparent, and fairly tough, is full of countless numbers of ova or embtyos. I have kept a portion of this spawn in salt water nearly a week; on examining it under the microscope today, I find many of tho embryos still alive and considerably developed. Very curious it is to witness the constant activity of these baby-nudibranohs, as they perform their rapid rotations within tho enclosing transparent mem- branes. Jn some of these only ono embryo is scon, in many, two are found ; and not unfrcquently, throo are seen to disport them- selves in one membrane or chorion. Conspicuous aro tho two oval lobes, which are thickly fringed with long, strong cilia, by means of which the little creature rows itself rapidly within its circumscribed " oval," and which aro destined to play the same locomotive func- tion when it is liberated from its chorion. Now these cilia are in motion, now they stop their machinery, and tho littlo croaturo partially withdraws itself into an exceedingly thin, transparent shell, somewhat resembling that of tho nautilus. Tho pedal process (foot) is apparent, and careful focussing reveals the presence of a delicate, transjiarent operculum on the under side of the foot. I see clearly the two circular otoliths in the region of the mouth; the stomach intestine and other viscera are evident enough, in a mass, bat not easy to distinguish separately, owing to its opacity. Tho muscle which attaches the embi-yo to tho bottom of the shell is scon in tho shape of a senii-trnnsparont conical organ. Nearly tho whole of tho rest of the body of tho embryo is separated from the shell by a well-defined clear space. Tho figures in Alder and Hancock's Monograph (Fam. I. pi. 3) are well shown, and what is before nio convinces mo of their accuracy. Of the thousands of thousands of ova contained in the spawn of tho nudibranchs, how few aro destined to survive and reward the marine zoologists by their presence as adult animals. I am reminiled ut what occurs in oysters. Delicate locomotive larv;e, when free swimmers, aro at tho mercy of tho rough waves, and in the troubled sea of their infancy they have but littlo chance of settling down to a quiet life, and developing the characters which murk tho respective adult species; so that, I should suppose, tho nudibranch babies require similar conditions to those necessary for the development of the young collated oysters, vie., a calm soa and a warm temperature, i secured one raoro nudibranch during ray short visit at Ililbro, a fine JMis papillosa. But, beautiful in colour and curious often in form as our nudibranchs are, it must be confessed that they are, as adults, dreadfully sluggish in their movements -painfully slow. This, 1 think, is especially true of Dori.1 tnherruliita. " Do move on, sir," ono repeals in vain. I call them " Cretans." Would you know why ? Because they are " slow bellies." Even as Epimenides calls the people of that island, in a lino quoted by St. Paul (Titus i., 12) : — Kp»}r«c «»< yl/ivarai, koki'i Sijpin, yaaripii; Apyai. Of course it is only tho latter description that is applicable to nudibranchs. W. UouurnoN. Hay 22, 1882. Coal Dndkb IvONDon. — .\t tho half-yearly mooting of tho pro- prietors of the Sonthwark and Vauxhall Water CJompany, it was mentioned incidentally that in sinking a now well at Streatham, pieces of coal had been founri LjO feet below the surface. — Daily Neivi. JtLT 7, 1882.] ♦ KNOV\^LEDGE ♦ gnslun-fl! to Corrrsponlifntfi!* *^* All commun\eation» for the Editor requiring early attention thould reach the C^ce on or before the Saturday preceding the current isiue oj Knowlbdoe, th» increaeing circulation of xhich compile ii$ to go to prett early in the tceek. HiKTS TO COBSISPOKBIICTS.— 1. Ab qnetfioni atlcing for icientijic in/ormation can be anncered through the poet. 2. Letters tent to the Editor for correepondentt cannot be forvarded ; nor can the namee or addreeeea qf correepondenta be gittn in anencer to private inquiriee, 3. Correepondente ehould terite on one tide otily of the paper, and put dratcinge en a eeparale teq/. 4. Each letter should hate a iiile, and in replying to a letter, r^erence should be made to its number, the page on which it appears, and its title, M. E. H. H. Your answer to " Pjranius" is not coirect. IIow do you make out fourteen for tliird year ? There would be twelve for lirst year, each of whom at end of year would pay £40, making, with £6,000 annual subscription, £6,480 ; out of whicli, twelve more would each receiTe £500. At the end of second year there would bo £6,960 for distribution, and thirteen (not fourteen) more sub- scribers would receive, each, £500, and so on. — il. J. Madge. As stated, we were referring to the idea as presented by our corre- spondent. Permit us to say that your way of putting the theory is entirely unscientific — the " evolution of immense volumes of electrical energy which, flj-ing ofi from the sun's body into space," ago of each subject on a separate small sliji of pa])er, or, if of sufficient importance, on two or more, varying the heading, as,— Spots i^n tbo Sun, by W. Uupgins, p. 113; Sun, Spots on, W. Uuggins, p. 113; Huggins, W., Spots on the Sun, p. 113. Ilieu sort ; first into letters, then under each letter into proper alphabetical posi- tion. — W. Lees. Wo have such a list ; but wo aro not free to lend it ; so far as wo aro concerned, wo ivould willingly do so. We do not belong to the society.— Serckast A. SnARPE. Many thanks ; but electrical and telegraphic articles already provided for. — Faheu.vt. That leaf (v., vi., in No. 33), is not to be bound with the volume. The advertisement ytar. ni foot of p. 47, was inserted by mistake of printers, as you can gntlicr by glancing over ndvertiscuieut columns. The contributiir you name has promised to do what those you refer to would not do, and his papers will have an independent value accordingly, and bo practically more useful; just as my valued friend F.R-A.S. describes nothing in his " Nights " which ho has not oianiincd at the telesco|» within o few hours of tho time of writing. —J. U. ConUETT. Four weeks of ill-health (we aro quite well again, thanks) must be onr excuse for not sooner replying. Liko you, we have never soon oitlar A'cnns or Eve, in painting or statue, represented otherwise than as a more or less be.iutiful young wonuin, born in the usual way. Michael Angelo, who repn-sentod Moses with horns, might Imvo venlurcjl on a bolder cours«' with either of those ladies, or with both. Many thatiks for your kiml advocacy.— J. L. 11. Thanks for solutions of mathematical probl.-ms. Wo give shorter and more general solution.— J. Gbkv. Doubtless the comet : see part of reply above to J. H. Cobbett.— Excelsior. See reply to J. II. Cobbett.- A JiNioK. It shonld hardlv bo necessary to say that I jwrsonnlly would prefer having more" astronomy; but 1 yield place to others, and ask others to do part, or must of the astronomy.— J. A. U. Tho diffi- culty has lK>en that description of the microphone turni-d out to lie very long and illustration rather exiKmsive. We cannot keep our corrcspondenia' promises.— P. H. D. The ice theory li;»s .lilficullios ; but if every year there is a cold spell due to ice, an.l the iiveraKO lime for thVis a particular part of May, that would .account fi>r tho observed fact— the thiTO cold days.— C. M. P.h.lk. Yea; t hero is room fi.r oil. Tho point is that with natuml increase, even as now checked in England, a few hundred years would overcrowd the earth, counting "humans" only.— .1. K. Yes; Browning's Rninbnnd Spectroscope shows the niin-sign admirably.— VkubI'si Sap. Yesj but how nU>ut tho prcprielors, if we thus do advcr- 100 KNOWLEDGE ♦ [July 7, 1882. k'aiiii; prjitis?— J. W. Bloom, Ed. Wo sliaU bo only too Kind to notioo the ntagnzinc ; as we \vni<>, your letter only to liaiiil from hca"i office. — A&ab. Alas ! we Imro never played Napoleon, and your iinestion is on enigma to us. — U. Sadler. Wo aj^reo with you, and bo, wo fancy, would our friend, F.U.A.S., en further consideration, that thu common proper motion of Castor and • implies that ti.ey art connected. — T. J. llU'KiN. Thanks. (1) It would be a pity were a chance given for " the enemy to blaspheme." Dr. Ball wont rather beyond iho record in saying that if all the planets did not rovolvo in the same direction, the solar system would have perished long ago." Perhaps 1 wont also beyond the record in saying " it would have been as well with the solar system as at present if some planets went one way and some another." Laplace proved that with all the planets going tho samo way round, and all with small inclinations and eccentricities, there could bo no destructive changes in tho solar system. liut, ho never proved Uiat if any even of tho large planets went tho wrong way round, there icouJJ be destructive changes. Dr. Ball, by sa.i ing, " at all events, tho larger planets," shows that ho recognises the quantitative character of tho problem, with which unaly.sis has never dealt in a quantitJitive manner. 1 am satisfied tho revolution of Jupiter the wn>ng way round would do no more harm than that of the earth or Venus — pel haps IcfS, when duo ro»unt isjtaken of the much greater scale of the distances in tho system of giant planets than in that of tho terrestrial planets. Albeit, this has never been ])njved. From the nature of liagrange's etjuations in dealing with this matter, it may be rogirdcd as shown that tho stability of the solar system would not bo absolutely certain, as now (without much moro inrjniry ) if any of the planets went the A-rong way round. (2) Any text book of geography which states that tho varia- tion of the major axis of the earth's orbit has influenced climatic relations, has undoubtedly bluudired. It should bo " minor axis," though the major axis is vci-y slightly variable, in long periods of time, in an oscillatory manner. You quote Mitchell's " Orbs of lloaven," but he was not competent to give an independent opinion on such matters. We find him confounding the parallelogram of velocities with the parallelogram of forces, and making other mistakes equally fatal to his position as an authority. — W. 1'akkeh. It is not easy to say what books would suit you, as tho range from the easiest to the most diffi,;ult is fo great. East and west are different in star maps and geographical maps, because wo look np to the skies and down upon tho earth. N'ote, however, that in my maps there is no right, or left, or top, or bottom ; but the middle is the top, and the bottom is all round.— E. T. C. W. Might yon not as well argue that since the moon affects tho tides, so may Saturn or Jupiter affect the ocean in some other, bat quite as marked, manner? Tho influence of the moon on lunatics, assuming it to exist, might depend in some way on her attractive, luminous, thermal, or magnetic influence ; compare any or all of these with any corresponding influence which any one of tho planets could exert, and you will see that astrology (which assigned much more putent influences to Jupiter and Saturn than to tho moon) cannot possibly derive supjiort, as you suggest, from lunar influences. — U. Wood. 1 referred to pure chance tossing, not to the skilful repetition of precisely identical tossings ; but I said suspicion would be justi- fied. There arc two theories -one that tho coin has two heads, the other that it is a fair coin — on the first tho chance of tho observed cvci^t is 1, on the other it is about 1-milliontli. Hence, the probability of tho first theory comes out, by the formula we gave, very much greater than that of tho second (supposing both antecedently to be equally likely) ; or it is most probable, though not quite certain, that a two-headed coin is Iwing used. If there were any feasible way of explaining as simply the occurrence of twenty tossings always as predicted, though not always of ono kind, precisely the same reasoning would apply to a ca«c where each of twenty to.ssings was in favour of the toi^ser. Suppose, for instance, tho theory to be that ho has one two-headed and one two-tailed coin, and that ho is HI) dcxternos that, while seeming always to toss ono coin, ho in reality changes Ihem at will ; then if ho wins twenty times in soccesHion, the chance of that theory being true would Ije much more likely than Ujo chance that ono coin is used, — even though the odds against )iis being so skilful and aliio so dishonest, were, antecedently, a hundred or a thousand to one.— K. Wood. Dear old Walkinghame-l had quite forgotten his rulf^ (usually very bad) ; but certainly thope you quote for division of decimals are pretty good, though that is an awkward scntcnco — " The 'jw.tient mvit hare »o nwny deriinal jilaccH an the dividend haa more Ihnn the divitnr " — regarded as a general rule, and in connec- tion with the fact that the dividend may havo/fu-cr decimal places than the divisor. — GsAliATiM. Jt is the cii«o that any map can bo iaint«r' or between "-^'"-"•^'"' or (writing for r its equivalent l+n) between lilzJ^jC and ^4rr^''' 2 2n 2 2» The larger n is the smaller is tho second term of each expression. But we may have n as large as we please, and so bring these two expressions as near to each other in value as we please. This means, of course, that the true value of each, when n is infinite, is gj} This, then, is the space traversed in time ( by a falling body starting from rest, under tho action of terrestrial gravity. That is, we have established the relation using for the purpose what may be regarded as an algebraical artifice — in reality, disguised integration. Before showing how this process illustrates integration, let as examine Newton's geometrical way of dealing with a problem such as the above. Note hov: cumbersome h'th procensts are. Let the time { bo rcprefentcd by the straight line A B, and the velocity acquired at the end of timo t (from rest), by the straight line B C at right angles to A B. Now suppose A B divided into a number of small equal parts, say into n paHs, each eresentcd by A M, A N, Ac, respectively. Sinee the vclocitv is proportional to tho time, it is obvious that all such points as P and Q will lie on tho straight line A C (for, otherwise, we should not have PM: QN: BC. Ac. :: AM: AN: AB). Now. if wo suppose tho falling body to mov,^ during any small portion of timo ropresonted by M N, with tho rolocity at the beginning of that time, represented by P M, the *|iaco tra- vers, d by tho body in that interval would bo rvpn>spnto 1 .lining very small. For sliding the rectangle •».. , AB to the position pq, and doing the like for all iL.- suiiiU i-;irullelo(jranis, wo have them finally covering the rectangle Ct ; and the area of this rectangle becomes as small us we please, when, n being luken as liu-gc as we please, kH becomes as small as we please. Therefore the area of the triangle ABC, which lic« between the two just named, may bo mado to differ from cither by an area less than uny that can bo assigned ; and this is tho samo as saying that this area correctly represents tho space fallen though from reit under the action of grnrity. Now AB = f, and 110" = ;)'. Uence area ABC-?i'- And s=^" 2 2 [Tlic reader must not fall into the mistake of supposing that wo are here equating a distance to a triangle. AB n'prescnts a period of time, and BC n velocity, — in this way only, th;it the number of nnita of length in AB are supposed to correspond to tho number of unit* of time in t, Ac. Just as we get tho right number for the ■qaare feet in a rectangle by multiplying the numfccrs representing tho lengths of the sides, thouirh feet cannot bo multiplied by feet to give square feet, so here we get a correct numerical result, by using the lengths of lines to represent numbers.] Now, in each of the above processes, we have employed an artifice, algebraical in one case, geometrical in another, to obtain a result such as the integral calculus obtains in a systematic We know in this case that the velocity at tho end of any time / is g t, or, in other words, that tho rate at whioh tho space traversed ia increasing, after time / has elapsed from rest, is j t. Now, wo showed in Paper I. tiat tho differential coefficient of ^ wiili respect to f is j t, explaining this to mean that the rate of increase of the expression 2— with the variation of t is represented by g t. Supposing, then, thot, in dealing with tho fall of a body under gravity, we know velocity at time t from rest, — or the rate of in- crease of t, the space traversed, at this time, — to bo gt, and also know that gl is the differential eoefficicnt of — — with respect to 'i — we can at once write « = -^ ± some constant. (It has not, indeed, been yet shown that two quantities can only hare the same differential coefficient when they are either equal or differ by a constant i|uantity j but for the present this is assumed, aa wo are now only illustrating tho nature and nso of differential coefficients, Ac.) And as when 1 = 0, » = 0, the constant must bo zero. So that we have, simply, «-.£- . In other words, from our knowledge that — is the quantity having nl for its differential co-efficient with respect to /, wo are at once able to say that a falling body whoso velocity at time t is gt, will in time t from rest traverse tho space £-. Tho notation employed for ■'■'■ ■■■•.». Note tliat what wo have to determine is "•' ' - described in the infinitely small intenals of *'" ■■ liolc time ( is supposed divided ; in other words »'■ ■' "f all small spaces, each represented by jt.At when Ai i« ti,, ,i,,remtnt of the time. This sum, which we should represent by igl.M, were the number of spaces not infinite, is in the integral calculua represented by pjl.dt, when the nnmbcr is infi. nitely great and M infinitely small, and wo write gt.dl ■= : — + a constant. /" How wc find tho sum corresponding to particular limiting values of the variable will be shown farther on. Of coarse, wc have here selected a case where wo know 1>ofore- hand that quantity of which the riropic expression we were dealing with is tho differential coefticiciit. In other cases, wo might hnvo more or loss trouble to determine this ; but a great number of diffeivntini coefficients are known, and in every such cnso wo can at oneo write down the cxpi-e.esionsof whieh they uro tho differential coefficients — or, in other wools, wc can at onco solvo our jirobleni. For other cases there are methods by which cither an exact or aj>pro.\inuito solution can be readily worked out. 'I'o sum up the elementary points thus far illustrated : — When there is ii iiiiinitilij lehose value dependu on some variable, the diferenlial cocili ii'iit of the quantilij with respect to that variable represents the rate at u-hich the quantity varies at the variable changes in value. When ifi) know the rate at which a quantity depending on some variable chanjes with change of the variable — in other u-ords, when we know the differential eocfficietit of tho quantity vith respect to that variable — we can determine the quantity itself, if only we Itnon- what quantity it is which has that differential coefficient. When wo have indicated how tho differential coefficients of n number of expressions can bo dotcniiincd, tlio impcirtniico of thesn points will be recognised. (ro be coutinuul.) Pkoblkm 11. — AVo prefer to solve this problem in the followi general form, us more instructive than a special casi : — Let AC, UD, the radii of two drums, he respcdirelj a and_ h (b > a) ; and let AB = d, required Ihv Icnjth if belling necessary for thern. Let OCD be a coinmun tangent luretiiig BA piodueod in d. Then, ()A : p tay i:c = a si.-' (-) He-jco lenglli of biltin,' rcqui ed = :J (aic EC + cD + are DF) is kncw.i. TiiK Poisonous Constituents op Tobacco-smoke.— A scries of experiments has been recently conducted by Herr Ki.ssling, of Bremen, with tho view of ascertaining tho proportions of nicotine and other poisonous substances in tlio smoke of cigars. His paper, in Dingler's Polytcchnisches Journal, gives a useful r(?sum(! of tho work of previous observers. Ho specifies, as strongly poisonous consti- tuents, carbonic oxido, sulphuretted hydrogen, prussic acid, picolino bases, and nicotine. The first three occur, however, in such small proijortion, and their volatility is so great, that their share in tho action of tobacco-smoke on tho system may bo neglected. Tho picolino bases, too, arc present in comparatively Rniall quantity; so that tlio poiscmons clinractcr of tho smoke may bo almost exclusively attributed to tho largo proportion of nicotine present. Only a small part of tho nicotine in a cigar is destroyed by the process of smoking, and a relatively largo portion passes off with tho smoke. The proportion of nico- tine in tho smoke depends, of course, essentially on tho kind of tobacco; but the relative amount of nicotine which passes from a cigar into smoke depends chiefly on how far tho cigar has been smoked, as tho nicotino-contont of tho unsmokcd part of a cigar is in inverse ratio to tho size of this part, i.e., more nicotine tho shorter tho part. Kvidcntly, in a burning cigar, tho slowly- advancing zone of glow drives before it tho distillable matters, so that in tho yet unburnt portion a constant accumulation of tlioso takes place. It would appear that in tho case of cigars that are poor in nicotine, more of this substance relatively passes into smoke than in tho case of cigars with much nicotine ; also that nicotine, notwithstanding its high boiling point, has remarkable volatility. — Times. July 7, 1882.] KNOWLEDGE 103 ^ur Chfss Column, By Mephisto. TIENXA INTERNATIOXAL TOURNAJIENT. Complete Score List. LIWMJI* W,%' Bird — 0100 01]0 01:iJ U'.'.l Blackburnc ... 10— !» 11 10 01 Ji 1101 EngliscU ll'ljI-irHiOjj'OlU Fleissig lOOOljO — COOO JOOO >.o Hruby OlOl'iill — OOlUUi.l Mackenzie llOlO il:ll 11 — iO 11 11 JIason OJVJHUOlil-llni ileitncr 01 OOllO 11 OOOOOJ — 01 Xoa iJO'loloO JOlOOOUillO- Panlsen iJl|ljl0OUilO5 00!iUl Schwarz IllOJ iJ[ll iJlOiO iOOl Steinitz !ll:10 4i,1101JHillll Tschigorin ... 11001^,01 01 lOOUOOOl Ware 'OOOOOO 11 OlO-i Oo'lOOl Weiss '0110ii|110iOniii ii; 11 Winawer jllllo|ll01 11 o. r. lii' Wittek JlOlilllOl ii i i Zukertort illOjOiOlll i I, 1 1 1 1 so 00 1 05 U I I ,i n I ; II ,'.1 ■ '.OU I ioioi — 51 1. 1111- ooijk on JO'l I 10 00 I 01 01 I 'a 00 oijii: 101 J IJOl . li.lJOljOS 00,00 0^ 10 13 iioooj'ooio -ioiiijii H!— |01 li 24 JO 10 — 00 1 8i 00:01:11— 22i Second Game or the Tie Plated on Jine 24. Whi: 1. P to K4 2. KKttoBS 3. QKt to B3 4. P to Q4 5. Kt takes P 6. Kt takes Kt 7. B to Q3 8. Castles BLiCK. Steinitz. PtoK4 QKt to B3 P to KKt3 P takes P B to Kt3 KtP takes Kt Kt to K2 P to Q3 Q to Ksq(a) Castles P to B3 11. B to K3 12. Q to Q2 13. QR to Ksq 14. P takes P 15. R takes R 16. Kt to K2 17. Kt to B4 18. P to QKt3 19. RtoB3 20. R to R3 KB3 P to KBi P takes P (I) R takes R (cl.) BtoK3 P to B4 B to Ktsq QtoQ2 R to KBs(| B to B2 (. ; ■Whitb. Black. Winawcr. Steinitz. ! 35. R to QRsq K to K4 I 36. P to KR3 (o) R to R5 (p) 37. P to B3 B to B5 38. B to B2 (<,) R to R3 39. P to KKt4 (r) P to E5 to. P to R4 R to Kt3 41. RtoQKtsq(s) R takes R 12. B takes R B to B 8 Ui. K to B3 P to Kt t (0 41. B toR2 P to B3 (>t) 15. B to B7 B to Q6 j 40. K to B2 (i) K to B5 47. P to R5 B takes P (,e) 18. B to ~ 49. B to R6 50. B to B8 51. P to RG 52. B to Q7 PtoQ4 P to B4 P to B5 K to K4 P to Q5 21. Kt to Qo (<0 P to R 1 {e) 22. Kt takes Kt(/)Q takes Kt 23. R to B3 K to Ktsq (•;) 24. QBtoKt5(;i)Q to K4 (i) 25. B to RC R to Ks(i (j) 26. B takes B K takes H 27. Q to B4 (i) y takes Q 28. E takes Q P to B5 (/) 29. P takes P (ni) R to K4 30. R to Bsq 31. K to B2 32. K to K3 33. R to QKtsq 34. P to QR3 53. PtakesP(ch) K takes P 54. K to K2 B to Q6 (cb) 55. K to Ksq 56. B to B8 57. K to Qsq .-)8. B to B5 59. K to B2 UO. K takes P 01. K toQt l!2. K to K5 03. K to B6 P to B6 K to KG K to B7 B t.-»kos P B to B8 B takes P B to Kt7 P to RG P to R7 P to R8Q KtoBG K to B5 R to QB4 («) 04. K takes P B takes P ! G5. K to KtG B to K3 { CO. P to Kt5 K to B3 I Resigns. R to R4 ' Notes by llerr Steinitz, from the Field. (o) Not a good post for the Q. Herr Winawor probably intended to support his Kt, in order not to bo subjectcil to the doubling of his QBP, while reserving the choioo of squares for liia QB. (h) Ho isolates the adverse P, but lie exposes himself to an attack which ho afterwards finds somewhat troublesome, and which sub- sequently required the greatest care in defending. ((•) Probably tho only move. It makes room for his^K, and liberates his Kt for action ; tho latter could not move at once ; for Wliito would have sacrificed the Kt for the KtP, which Black could not venture to retake with the K, on nccount of the rejoinder, P to K5 ((lis. eh). (d) White is not to be tempted into saci-iCcing the Kt, whereupon tho game might have proceeded thus : — Whitb. BtiCK. I WinTF. Blxci. 21. Kt lakes P Kt takes Kt 22. B takes RP RtoKRsq.and I should win. (t) Again the only move ; if Kt to Kt sq. White could still take off the RP, for if the B retook, the reply R takes B(ch) would win. since the Kt could not retake, on account of Kt to BO(ch) ; if, how- ever the Kt then took the B, White would mate in a few moves, commencing with Kt to B6(ch). (/) ^\'hite judiciously gives up all attack which he could no: sustain ; for instance, by P to KKtl — since Black would then pin the P by B to K3, and afterwards Q to Q2. (g) First part of a plan for inducing the opponent to exchange pieces and to bring about an ending. (h) With the view of driving the Q to K4, and in order to te enabled to oppose Queens at KB4 subsequently. (i) She cannot retreat to Q2, as tho B would be opposed at BG with advantage. (j) It would have been very unwise to check with the Q at R8, and then to take the QRP ; White would interpose the R, followed by B takes B, Q to B3(ch), and R to Hsq, with an excellent game. The move in the text is another preparation for this game in thi- ending, as will be seen on Black's 28th and 29th move. (i) The offer of exchanging Queens is ill advised ; White would have had a perfectly even game otherwise. Herr Winawer sub- sequently admitted that he had ignored the effect of Black's next move after exchanging. (l) This move exercises a most important effect on Black's prospects in the ending, for it forces tho separation and isolation of White's Pawns on the Q side. Steinitz. BUCK. (»i) He could not evade the unpleasant necessity of capturing, for, if he moved the B to K2, Black would still answer R to K4; threatening R to QR4, and also to win a P at once by P to EEt4. (n) Stronger than R to QR4, e.?. :— WuiiF. Buck. 30. RtoQRt 3 1. R to QB7 R takes P 31. R to Ktsq K to B3 35. P to K5 P takes P 32. R to Kt7 P to B 1 3G. B to Kt.withastrongattack 33. R to Q7 K to K3 (o) Not a good move ; V to QB3 was better. (p) Black threatens now to bring tho B round to QB3 via Q2. (•;) Obviously he could not afford to exchange, as his separated Pawns would soon fall, one by one. (r) This compromises the position of his Pawns on tho K side, too ; as, after tho exchange of Rooks, which is soon inevitable, they are all placed on squares on which they can bo attacked by tho hostile B. («) Ilo could not afford to allow tho R to reach Kt7, as his two pieces and the K would bo too much confined, and an uufavonrnblc exchange of Bishops could be easily forced, after which the R would gain accois at KR7, taking the KKP. (() Better than taking tho P, whereupon White would have blocked in tho B by B to Q3. (ii) Necessary in order to prevent the adverse B from reaching Q5, and then 'defending alternately by B to B6, Kt5, or Q& accordingly. (i) Perhaps in the hope that Black might take the P with the K, 104 ♦ KNOWLEDGE ♦ [July 7, 1882. whereupon Wliito vroald win a piece by B to Kt(>(i-li'). IIo could, however, no niorv protect the P ; if B to KtG, Illack could ndvauco I'toQl. (•j) Black has it :U1 his own wnv nftor this, niid rests cney. ANSWERS TO CORRESrONDENTS. •»• Please addrets Chesf-Editor. T. Gillespy.— Prohlom 4o. If 1. R to U3, 1. 1' tjikcs B, and there la no mate. A. A. B. — Game received : will apjvcnr n? soon as possible. Problem 45 correctly solred by Moleqne, Scncx Solitarius, Francis J. Drake. ^ur 22H()idt Column. Bv " Five of Clubs." RETURNING PARTNER'S LEAD. TnERE is scarcely any more obnoxious rule nt Whist than that which many good players of their own hands insist upon, that partner's lead should almost always bo at onco returned. The player who always returns your lead nt onco is more nnnoyinp; even than the one who, when the right time has come for returning it, insists on keeping to his own suit. I would oven take exception to Cavendish's rule that "with only moderately strong suits, which you open to a disadvantage, you do better to return your partner's original suit, or to lead up to the weak suit of yuur right-hand adversary, or through the strong suit of your left-hand adversnry," than to open yonr best suit, — unless by the words, " which you open to a disadvantage," he means to qualify the ex- pression, "moderately strong suits," and not (as it seems) to make a stntement respecting sKch suits. It is clear that, with only weak thrcocard suits outride trumps, yon do better to return your partner's suit than to lead one of your O'vn. On the other hand, with a tolerably strong three-card suit, headed by a senoence, you do better to lead your own suit. With a four-card suit headed by anything bolow a Knave, you might return him his suit ; but with such a suit as Knave, nine, eight, three, you ought in my opinion, to show your own suit before returning his — esjic- cially if j-ou have good cards in your short suits, so as to have a good chance of an opportunity to lead again to him. This is always to be considered ; for if you have only a moderately good long anit, and weak cards in the other suits, you may have but one chauce of returning his lead, while it may he of preat importance that he should bo led to, and not have to load himself. Besides, ho may h.ivo a strong suit, which may bo ostablis'hcd if ho gets a return lead, and ho may then lead trun-.ps, and make a great game ; whereas, if you lead your own moderately strong suit, you almost certainly throw the play into the adversaries' hands. There are some casei-, however, where, even when you have a strong suit, yt,u should at onco return your partner's lead. Thns, if after taking the trick yon remain with tho leading card in hi.s suit (which tiie play shows to bo strong), you should play out that card in order to clear his suit. Again, if you held originally only two in his suit, and are weak in trumps, you should return his Ica»t imimrtant rule, in returning partner's lead, and one of the most important general rules at Whist, is to return the highest of two remaining cards, the lowest of three or more. Tho only exceptions to this rule are that (1) with the winning card and two other* (left after firnt round) you lead the winning card, and (a), with second anri third Ijest and another (after lirht round), you lead tho iccond Uit, not tho small one. With these exceptions (and an «ca«ion or two, perhaps, where your partner is nttcrly wf«k, and you wish to deceive tho enemy), this rule is im- (>crmtiva, and extends Ibroughoat the whole range of the suit. Thus, with •!■, 3, left after first round, tho return of tho 3 would be a gross Whist blunder, as would bo tho play of tho 4, if, besiiles tho <1 and 3, you hold tho 2 also. In those cases nothing is directly gained or lost by tho load of l or 3. Yet tho rule had its origin in considerations of play. For with such cards as Queen and a small one, or Knavo and a small one (lifter first round), tho lead of Queen or Knavo is manifestly good policy ; for thereby you strengthen your partner : yon ars numerically weak in tho suit, and most jirobably lose nothing your- self; whereas with Queen and two small ones, or Knavo and two small ones (after first round), you do well to keep back tho Quocn or Knave, being numerically strong, and having a fair clinnco of not only mnkinv! tlio honour, but remaining with tho best card in tho suit after three rounds. In trumps, this rule is even more important than in plain snits. Tho whole strategy of the game may bo ruined by your telling your partner (as you do in returning his lead wrongly) that you hold originally only three trumps when you really held four, or that yon held four when in reality you only held three. A player who neglects this general rule, of which, of coarse, no Whist player is ignorant, can only bo regarded as a very poor player indeed. Scarcely inferior is tho ])Iaycr who, when this signal is given him, fails to notice it, or who overlooks it when it occurs in tho play of his adversaries. Omitting to notice tho signal for trumps either in partner's or adversaries' play is in compariflOB a small offence. DoL-iiLK Dlmmv Peoblkm. — Lieutenant-Colonel Drayson gives the following ingenious little double dummy puzzio : — Givo tho adver- saries four by honours in every suit ; givo yourself and partner any of tho othor cards you choose, and win five by cards against them, you to havo tho lead. Valuk or Goon Play. — A correspondent, as a further proof that good play must tell, gives ns his oxpcrience, which was care- fully taken down. In two years' play, he tells us that the first year ho played 2,0G0 rubbers, winning 1,0117 and losing 072, leaving a balance of 12j to the good, and, counting points, ho won 5,893 and lost 5,233 — a balance of GOO to tho good. And in tho next year he played 1,G2G rubbers, winning 855 and losing 771, or u credit of 8i ruhbers, tho points being 4,701 wins, 4,15!) losses — showing balance of 652 to the good. In tho jjrovious year ho l)layed 2,029 rubbers, winning 1,107 and losing 922, leaving ISo balance on tho winning ; but that year ho did not koop a record of points. This is, of course, a much higher winning average than Cavendish's ; but, as our correspondent admits tho inferiority of his player compared to Cavendish, probably the element of luck stops in hero, lie adds that, in his long exjiorionoo of )ilay, thoro was never a week, scarcely even a sitting, that ho did not see at least one rubber lost by bad j)lay or won by good. NOTICES. The Back Numbers of Khowixdok, wilh the exception of No«. 1 to 7, »r» in print, uud cud tto obtained from uli bookHellopH and uewMaffenlfi, or direct from the PiitiliftherH. Rhnnid any diflictilty ari«e in ot)taiDiii|; the puper, an application to the PiitdishprB i« recpectftilly rc-quented. The FirKl Volume of Knowi.kdoii i« now to„Ay, bound in red cloth, cilt lettered. Price lll». 6d. Vol. I. rnnlniiin the iiuiiilwrH frnm the rollimence. ment (Not. 4, 1S81) to No. 30 (May nil, 1HS2). An ihero in only a Umitcd number of copies, the Publinhera advise that orders should be sent ia without delay, to prevent disappointment. The T lie Paije and Index to Volume I. is al".. ready, price ?d., post-free 2\A. Bindinf; Ca>es for Volume I., price Is. «d. eacli. Complete copies twiuul (includinK Title, Index, and Case) for 2h. ij.l. emh. The PoHt-otiice regulations prevent thi* transmission of volumes and cases through the post. The following Monthly Part* of Kkowledoe are now to be had (Paris I. and IT. beini! out of print) : — Pa>T III.- (Jan., 1882.) Containing fournnmhers. PiaT IV.— (Feb., 18-2.) Containing four numbers. Pi«T v.— (March, 1SM2.) Containing live numbers. Pakt VI.— (April, 189!.) Containinu four numbers. P»BT VII.— (May, 1882.) Contttininc four numbers. Part VIII.— (.lime, 1882.) Conlaining live numbers. ) the Publishers, as no further reprints will be ordered, Price ind. Post-free, Is. Price led. Post-free, Is. Price Is. Post free. Is. 2d. Price ind. Post-free, Is. Price liid. Post-free, la. Price Is, Post-free, Is. ad. make eutly applieatiOB TERMS OF SUBSCRIPTION. The terms of Annual Hubscription to tho weekly numbers of Khowi.bi follo«s:- To any address in the United Kingdnm To the Continent, Austrolia, New Zeaknd, South Africa 4 Csnoda To the Uniled States of America J3.Z6. or To the East Indies, China, 4o. (wd Brindisi) All sabscriptioDS are payable in advaoco. P. O. Orders and cheques should be made payable to the Publishers Wmili * Boss. London, al the Uigh Uolbom District Posl-olllne. Acent for Americn— C. 8. Carter, American Literary Bureau, Tribune I New York, to whom subscriptions can be forwarded. OFFICE: 74 4 76, GREAT QUEEN STREET, LONDON, W.C. July 14, If ♦ KNOWLEDGE 105 ^iXtY"^" AN ILLLLSJRATF.D ^Jy^ ^ MAGAZINE OF>CJENCE ^^ ^ FLMNLnfORDED-EXACTLYDESCRIBEPj LOXDON: FRIDAY, JULY 14, 1882. Contents op No. 37 July Flowers. By Grant Allen Ill Ristori's Lady Macbeth 112 Butterflies aud Moths. By W. J. H.Clark 113 Fire Hisks from Eleetric Lighting... 113 A Theory of Foresights [IllH.lrided) 111 AVeathef Diagram for (he Wee]; ... 11.5 Corresponilence llfi Our Mathematical Cu THE COMET SEEN DURING THE ECLIPSE. By a. C. Ranyard. ri"^HE accompanying sketch gives the position of the J_ comet, as shown on my photographs, with some of the more marked rays of the corona stretching out from the sun's liuib on tlie side towards the comet ; hut no attempt is made to indicate the smaller structure of the corona. The scale of the wood-cut nearly corresponds with the largest of the photographs. It will he seen tliat the head of the comet is situated at ahout a solar diameter from the sun's limb, and that the tail is greatly inclined to the line joining the head of the comet with the sun's centre. There is a slight curvature of the comet's tail ; but its general direction is such that if a medial line, which we will call the axis of the tail, were produced, it would not pass through the moon's disc. It is evident that this inclination of the tail cannot be merely due to an edcct of per- spective, the tail of the comet being really radial, and the nucleus situated on this side of the sun's centre, or on the opposite side of the corona — for a straight line can only be projected into a straight line or a point ;"and if the sun's centre lay upon the axis of the comet's tail pro- duced, the tail, from whatever position it w^as viewed, would always appear as radial to the sun's limb. A little consideration will thow that the inclination of the tail to the line drawn from the sun's centre to the head of the comet may have been greater than it appears in the photo- graph, but it cannot have been less. 1 hough the fact that the tail of the comet was greatly inclined to the radius vector struck me on first examining the photographs, the probable significance of the fact has only recently occurred to me. Small jets issuing in various directions from the nuclei of large comets have frequently been observed, but these jets do not extend to any great distance from the nucleus ; and, as far as I am aware, they have not been observed extending beyond the outer envelopes of the head of the comet ; while the chief tail into which the envelopes of the head merge streams away in a direction opposite to the sun. If the comet were moving freely in space (that is, not in a resisting medium), and a repulsive force from the sun was the only force acting upon the matter of the tail, we should expect to find the tail either straight, or curved in the plane of the orbit of the comet, when the velocity with which the matter of the tail is driven away is very great, compared with the orbital velocity of the nucleus, we should expect to find a straight, or very nearly straight, tail stretching away from the sun; but if the velocity of the matter of the tail is not very great, as compared with the orbital velocity of the nucleus, we should expect to find a curved tail, with the part in the immediate neighbourhood of the nucleus directed away from the sun, for the matter of the tail on leaving the head of the comet would have an orbital velocity which would carry it onward equally with the nucleus, if undisturbed by a resisting medium, and the small particles of the tail would only drop behind as the motion of the nucleus and particles of the tail were changed by the central forces acting upon them. But if the comet were moving in a resisting medium, the small particles of the tail would lose their orbital velocity more rapidly than the matter of the nucleus, and the tail would have the appearance of being blown backwards by a wind. Having regard to the direction of the curvature of the tail, which is slightly concave towards the south, and to the inclination of the general axis of the tail to a radial line drawn from the sun's centre to the nucleus of the comet, we may, I think, assume that the comet was moving in an upward direction, but whether towards us or away from us, and whether it was nearer or more distant from us than the sun's centre, or whether it was coming up to or had passed perihelion, must, I fear, remain a mystery. The comet observed by Sir I. Newton in 1G80, and th. comet of last year which was referred to by Jfr. Proctor as having not improbably had its period sliortencd by tlie resistance of the corona, both, probably, passed within a third of a radius of the sun's surface. From general reasoning one would suppose that under the inliucnco of solar gravity the density of the gaseous atmosphere of the corona would increase rapidly as we descend from the outer limits of the corona towards the photosphere, but our want of knowledge with respect to the tfmper.aturo of the coronal area and the behaviour of dust particles and gaseous matter at such high temperatures prevents our tiuiking any useful assumption with respect to the law of increase of density of the solar atmosphere. It is known that in tlic chromosphere at the base of the corona, liydrogcn, and many of tlie terrestrial elements, give a spectrum of narrow lines similar to the spectrum 100 • KNOW^LEDGE [JCLY U, 1882. ^'iven in terrestrial laboratories under very small pressures; r.ut, whatever the density of the gaseous matter of the chromosphere may be, there are facts which render it pro- liable that tliere is a resisting medium within the coronal area which increases in density as we descend from the outt-r limit-s of the corona towards the photosphere. The struL-turos in the lower parts of the corona are more curved than the rays which extend into the outer parts of the corona, as if" they had been acted upon and bent by cur- rents in an atmosphere, and the contorted forms of some of the irruption prominences also indicate the existence of I resisting medium. Definite evidence with respect to the . \istence of such a resisting atmosphere has been deduced from observations made by Professor Young with respect to the rate of projection of irruption prominences. See a paper by Mr. Proctor,' published in the Monlh'i/ Xotices of the Royal Astronomical Society for December, 1871. The comet oliserved during this eclipse is not the only cometary body which has been observed in the neighbour- hood of the corona daring an eclipse. The photographs taken by Mr. Davis and Col. Tennant, during the eclipse of 1S71, show an opaque nucleus, with dark concentric structures partially surrounding it, which cut out the light of the bright parts of the corona, and seem to have been due to a small comet situated between the earth and the corona. An account of these dark structures is given in the ^fonlh(l| Xotia-1 for June, 1874. Professor Winnecke, in describing the corona, observed during the eclipse of ISCO, also speaks of a dark body which appears to have lieen unconnected with the corona ; he describes it as a parabolic dusky arc, which looked as if it was drawn with sepia upon the brighter background of the corona. A drawing of this curious body is given in the memoirs of the Imperial Academy of St. Petersburg, 7th Series, Vol. lY. THOUGHT-READING. Bv THE Editor. IN the cases last considered, the explanation may be sug- gest<'d that some code of signals may have been arranged "y which the proper answer was communicated to those 'jue-stioned. ThefoUowing cases arc free from this objection : — " It will be well to give," writes Prof. Barrett, " a group of results obtained when no member of the family was aware of the .selected oVject Eleven times running we cho.se a card at random, and on .six of th<-.se occasions one of the children named the selected card (giving both suit and pips, or fully de&ignating the court card) correctly at the first trial ; twice the card was named correctly on the second trial ; and three cases were failures. On none of these occasions was it even remotely pos.'sibly for the child to obtain by any ordinary means a knowledge of the card selected. Our own facial •■xpre.s.sion was the only index open to her; and even if we had not purposely looked as neutral as po.ssible, it is difficult to imagine liow we could have unconsciously larried, .say, the two of diamonds written on our foreheads. The outline of results during the present investigation, which extended over six days, stand as follows : — Altogether, .382 trials were made. In the case of lett<.rs of the alphal>et, of cards, and of numbers of two figures, the chances against success on a first trial would naturally be ■_'.'> to 1, 51 to 1, and 08 to 1, respectively ; in the case of hiimames they would, of course, be indefinitrily greater. Oards were far most frequently employed, and the odds in their case maybe taken as a fair medium sample; according to which, out of the whole series of 382 trials, the average number of successes at the first attempt by an ordinary guesser would be 7 J. Of our trials, 127 were successes on tlie first attempt, .50 on tlio second, 19 on the third, making 202 in all. On most of the occasions of failure, 180 in number, second trials were made ; but in some ca-ses the guesser professed inability, and declined to make more than one, and in others we allowed three ; no trial beyond the third was ever allowed. During the last day or two of trial, after it had occurred to us to notice the point, we found that of the failures to guess a card at the first trial, those wrong both in suit and number were a small minority. Our most .striking piece of success, when the thing selected was divulged to none of the family, was five cards running, named correctly on a first trial ; the odds against this happening once in our scries were considerably over a million to 1. Wc had altogether a good many similar batches, the two longest runs being eight consecu- tive successes, once with cards, and once with names ; where the adverse odds in the former case were over 142 millions to 1, and in the latter something incalculably greater. If we add to these results others obtained on previous visits, it seems not too much to say that the hypothesis of mere coincidence is practically excluded." "The exceptional nature of this inquiry," proceeds Professor Barrett, "goes far to invalidate arguments founded on character and demeanour ; and, on this head, we will only state our conviction that any candid critic, present during the whole coursie of the experiment, would have carried away a far more vivid impression of their genuineness than the bare printed record can possibly convey. Of more real importance is the hyi)othesis of exalted sensibility of the ordinary sense organs. We could discover no indication of this in any of its known forms ; but by way of precaution, as has been already stated, we commonly avoided even whispering any word, number, or name that we had selected ; and the position of the ex- cluded child, when the door was opened, would in every case have satisfied the most exacting critic. The explana- tion which might be sought in unconscious indications given by the sitters, and especially in the movement of the lips, has been already adverted to. Coming as we did to this investigation with consid(!rable previous experience of the same kind, we were throughout strictly on our guard against giving such indications ourselves ; the possibility of their being given by the family was, of course, excluded where the family were ignorant of the selected word or thing ; and on the remaining occasions our perpetual vigilant watch never detected a trace of anything of the kind. The ab.solute docility of the children — both the guesser and the others — in taking any position in the room that wc indicated, was naturally an a.ssistanco to our pre- cautions. It may be further mentioned that, on a pre- vious visit made by one of us, the child called the required name through the shut door, or from an adjoining room, having thus been completely isolated from the very beginning to the very end of the experiment."* Other evidence of this sort will be considered further on. At this stage it may be well to note the objection raised by Professor Donkin. " The matter in question," • " Among the friends above roforrod to as having taken part in thcBO inqniricH are IVofessor Balfonr Stewart and I'rofosaor A. IJopkinHon, of Owen's Collogo. A communication lately received by uB from them, embodying the results of their visits, and written without any knowledge of the contents of this paper, states f.'iots and instances criticisms as to the possible (or impossible) relation to those facta of coincilence, collusion, iiiijhl, and hearing, precisely similar to those we have given. Their experience waB that ' in about half the cases the first guess was rif,'lil,, and in most cases of mistake there was some marked point o£ similarity between the object proposed and the thing guessed.' " July 14, 1882. KNOWLEDGE • 107 he says, " has obtained a somewhat undue prominence of late ; but if it is as simple and intelligible as it appears to be to most who have investigated it with care, and with minds free from mystical liias, any aid towards the extinc- tion of what must then be regarded as an ig»is j'ahnts of pseudo science carries with it its own justification." Passing over cases in which there was actual contact between the persons guiding and guided, Professor Donkin remarks that in cases where there was no actual contact, " common sense demands that every known mode of ex- planation of facts should be exhausted before the possibility of an unknown mode is considered." " It is equally obvious that in all scientific inquiries the good faith of individuals concerned should form no part of the data on which the conclusion is to rest. We can never call on science to put deception out of court by a belief in any one's integrity. Half of the evidence which has propped up the spiritualistic craze is based on the results obtained through mediums of " unblemished character " in private families, whose virtuous reputation has been largely sus- tained liy the fact that they did not take money for their trouble ; no regard being paid to innumerable other motives and tendencies to deception." (This is very well put.) He then considers the "code of signals" ex- planation, which " fully serves to cover all the facts in question," though it is only by straining the evi- dence that the cases in which no members of the family were present when an object was selected, that Professor Donkin makes out this point. " From the only rational point of view," he says, " that of scientific scepticism, and, therefore, with total disregard of the personal factor, this consideration seems in no way to invalidate the line of comment here taken. It is not clear to how many of the three observers the pronoun ' we ' in the passage [above] refers, but, at any rate, we miss entirely in the paper an_y specific quotation of results obtained in the latter set of circumstances. But even if this evidence liad been forthcoming, no mere ipse dixit on such a matter could for one moment be admitted. Reason would require us to entertain the great probability of mental bias in some, at least, of the observers, or to discredit the accuracy of their memory, rather than to allow that any- thing has been adduced in this account of what (to say the least) must be regarded as superficially-conducted experi- ments, to warrant a recognition of any no\elty, or by con- sequence to stand in need of explanation by a theory of 'brain-waves.'" The spirit of extreme caution here indicated is alto- gether sound ; the objection to novelty, as such, is as entirely unsound. Nothinr/ could prove that mind acts on mind if Professor Donkin's principle were accepted in its full ex- tent. The theory might be established so far as he him- self was concerned, by an experience of his own, but no one else would be bound to accept it, and it cannot possibly be proved to cacli person separately and individually. Professor Donkin seems imaware of the fact that Dr. Carpenter, who has dealt with such subjects more clcsely perhaps than any living man of science, and always from the sceptical side, admits all that, as I conceive, even Professor Barrett and his colleagues consider proved. In the following j)assage the reader will note the distinction between what Dr. Carpenter has been led to suspect, and what he regards as beyond question : — " Everyone who admits that ' there are more tilings in heaven and earth than are dreamt of in our iihilosophy,' will be wise in maintaining a ' reserve of possibility ' as to phenomena wliich are not altogether op/ional to the laws of physics or physiology, but rather transcend them. Some of njy own experiences have led me to suspect that the power of intuitively perceiving what is passing in the mind of another, which has been designated as ' thought reading,' may, like certain fonns of sense perception, be extraor- dinarily exalted by that entire concentration of the atten- tion which is characteristic of the states we have been considering. There can be no question that this divining power is naturally possessed in a very remarkable degree by certain individuals, and that it may be greatly improved by cultivation. So far, however, as we are acquainted with the conditions of its exercise, it seems to depend upon the unconscious interpretation of indications (many of them indefinable) furnished by the expressions of the coun- tenance, by style of conversation, and by various involun- tary movements; that interpretation, however, going, in many instances, far beyond what can have been learned by experience as to the meaning of such indications."* " Look- ing at nerve force as a special form of physical energy, it may be deemed not altogether incredible that it should exert itself from a distance, so as to bring the brain of one person into direct dynamical communication with that of another, without the intermediation, either of verbal language, or of movements of expression. A large amount of evidence, sifted with the utmost care, would 1)6 needed to establish even a probability of such com- munication. But would any man of science have a right to say that it is impossible ^ " (To he ronlinuod.) A STUDY OF MINUTE LIFE. By Henry J. Slack, F.G.S., F.R.KS. A SPECIMEN" of bottom yeast— the unterhefe of the Germans — taken from a vessel in which fermentation had been arrested for some time, showed, under a magni- fication of 200 linear, that the little plant cells had been starved. All of them were much too small, and instead of being appioximately globular, many were sausage- shaped, some like thin cylinders, and amongst them many minute beaded rods, which would be ranked amongst the Bacteria. Any further fermentation carried on under such circumstances would give rise to products not wanted in any process of brewing or wine-making, and, if nothing worse happened, a good deal of vinegar would be formed at the expense of the alchohol which resulted from the action of the true yeast cells. Beer or wine in that condition is popularly said to be pricked. Pure diluted alcohol has no tendency to undergo a fermentation into the vinegar condition, but if any of the microfungi of the ^■inegar-plant sort are present^ and also some easily oxidable vegetable matter, the acetic change soon occurs. One of the best modes of making vinegar on a large scale is to cause a fluid containing alcohol and sweet;-wort to trickle slowly over wood shavings or birch twigs. A slimy substance forms in a few days all over the shavings or twigs, and this modifies the alcoliol into acetic acid. If the slimy stufT is examined under the microscope, it is found to contain, besides yeastrlike cells, millions of small beaded rods — a kind of bacterium. Both brewers and wine-makers arc much troubled through • Dr. Carpenter then mentions some very curious oxamploa related in the autobiograiihy of Henrieh Zsehokke, who (according to his own Btateniont) possessed this power in a very remarkable degree, frequently beinp able to describe, not only the gener.jl course, but even many particulars, of tho past life of a person whom ho saw for the fu-st time, and of whose history he knew nothing what- ever. 108 KNOWLEDGE ♦ [July 14, 1882. these aud various microfungi they do rot want iutrud- in-' into tiieir fermentations, and giving their liquids a ^IaJ flavour. In other very numerous cases the l*tr or wine seems all right at tirst, but will not teep. Whether in cask or bottle, some of the intrusive ferments continue in operation, either producing vinegar, or some other substance with an objectionable llavour. To minimise the danger, brewing should l>e carried on in pure air, and with tlie greatest regard to cleanliness. Fer- menting the wort in a warm temperature, as is common in tliis country, is more favourable to the growth of the un- desirable organisms than the cooler process so much employed in Germany. It beer, made by " high fermen- tation," that is at a warm temperature, and with the yeast cells rising to tlie top, is intended to keep for a length of lime, or to stand a sea voyage, it must be strong and well hopped, the aromatic oil of the hop being unfavourable to the growth of microferments. Besides getting sour, l.eer and wine arc liable to turn ropy and putrid, through the action of special ferments whose germs are very widely diffused. Slender beaded organisms, straight, curved, or spiral, some quiet, others in quick motion, preside over these changes, producing what Pasteur calls various " maladies " in the fluids they attack. The " low fermentation " goes on slowly at low temperature, and the veast falls to the bottom of the vessel. Tlie temperature should be about 4.")° F., and great quantities of ice are used in the German breweries to enable the process to be carried on during the warmer months. The beer is also kept in cool cellars, and Pasteur states that nearly 2 cwt of ice is consumed in getting 22 gallons of beer ready for sale. If well made and carefully bottled, this kind of beer will keep without being of great alcoholic strength, or highly hopped. If wine is likely to be affected by the intrusive fei'ments, Pasteur recommends bringing it near the boiling point after it is put into bottles. This kills the microferments, and, if carefully performed, leaves the wine with a good flavour, but it is said that when so treated it does not improve with age. It is interesting to let a saccharine fluid spontaneously pass into the acetous fsmientation and examine the orga- nisms under the microscope. If a little yeast is used to start the alcoholic fermentation, and the liquid is then left for some time in a warm place and exposed to the air, it is pretty sure to turn sour. From a wide-mouthed bottle con- taining an ounce or two of a saccharine fluid so treated a little ropy mass is taken from the bottom and found to be couifKised of vast multitudes of minute beaded threads thickly interlaced. Sometimes a leathery mass is found — the so-called " mother of vinegar," or vinegar plant. Many families make tlieir own vine/zar by its means. They put it into a pretty strong solution of coarse brown Kugar, and in a few weeks find it is turned to good 1-inegar, and the plant greatly increased in thickness. It is then like a stout piece of wet buff leather, and easily splits horizontally. If a small piece is jilaced in a bottle such as is used for Pre.ston salts, in a solution of lump sugar, a growth is soon obtained transparent enough for convenient examination. After viewing it with a low power, one of 400 or more diameters should be used. A numljtr of ycas^like cells, a.ssociated with multitudes of Ijeaded, rod like cells, are then seen to be immersed in a mavs of tough, gelatinous matrix. If a vinegar plant is taken out of a vessel, with a sufllcient depth of fluid to ke«-p its under surface and part of its thickness conqjletely submerged, and placed in a sliallowcr one, so that it is much more exposed to air, it does not continue to carry on tlic acetous fermentation, but i» soon covered with crops of blue mould. The sugar disappears, gets slowly burnt up, but neither vinegar nor alcohol is obtained. In some experiments by the writer, publislied in 18G5 by the Microscopical Society, it was found that vinegar plants dried in an o\en, at a temperature too low to burn them, were reduced to a state like dry gelatine, which clicked when thrown upon glass. Exposed to the air they absorbed moisture, and when thoroughly wetted the various cells appeared uninjured, but most of them uo longer produced the acetous fermentation. In one case, the butyric fermentation occurred in a saccharine solution, evidenced by the peculiar and very nasty smell of highly rancid butter. In another case, after six months' immer- sion, a dried piece of the plant began to form vinegar, and produced loosely aggregated cells which carried on the process. The same kind of cells may produce quite different effects under varying conditions. They may take the oxygen they want from the air, or, if that is excluded, obtain it by decomposing some substance present. The number of new combinations that may bo produced by partial decompo- sitions and oxidations is indefinitely large, and may give rise to "maladies" of beer, wine, butter, ic, aud in the human organisms, to various diseases. WAS RAMESES II. THE PHARAOH OF THE OPPRESSION? By Amkli.\ B. Edw.\hds. IV.— THE CONSECUTIVE AND SYNCUEONOUS IT is difficult to make even the roughest historical calcu- lation without some use of dates ; but, as I have already said, no dates that can be applied to this early epoch of Egyptian history are other than approximate. \V'e may estimate the number of years whicli elapsed between one given event and another given event, and wo may thence calculate our way to a third event, and all three conclusions may be relatively accurate ; but to label any one of the three with a positive date i>.c. is, in the present state of our knowledge, impossible. Still it is necessary, if only in order to be intelligible, temporarily to accept a fixed date of some kind ; and for this purpose I propose to accept Mariette's date, ac. 1462, for tho beginning of the XlXtli dynasty. Mariette, it should be said, founded his chronological system on the historical lists compiled by an Egyptian historian named Manetho, who was high-priest of the Great Temple of Jleliopolis and KeejK-r of the Archives, under Ptolemy Philadelphus, u.c. 284-246. Manetho, though a native Egyptian, wrote in Greek, which was the language of the Ptolemaic court (just as Turkish, and not Arabic, is now the language of tlie court at Cairo) ; and in Greek he com- posed his famous "History of Egypt," whicli was either a direct translation of ancient historical papyri, or an original narrative based upon tliose early chronicles. This invaluable work lias perished ; but some precious quota- tions from it are found in the writings of Josephus, Eusebius, and George the Syncellus before-mentioned. Above all, the great clironological list of dynasties and kings from Mena to Alexander is preserved entire in the works of several Christian clironologibt.s. Following this list, Mariette places the XlXth dynasty between ac. 1462 and ac. 1288. The first three Pharaohs of this dynasty were Rameses I., Seti I., and Pvamescs II. Tabu- July 14, 1882.J ♦ KNOWLEDGE ♦ 109 lated according to the nuiiiLcr of their regnal years, as recorded on the monuments, they stand as follows : — Rameses I. reigned G years. Seti I. reigned 51 years. Rameses II. reigned 67 years. To calculate these reigns would, at first sight, seem straightforward enough. If Rameses I. began the dynasty B.C. 1462, must not Seti I. have succeeded u.c. 14.56, and Rameses II. b.c. 14051 And would not the sixty-seventh and last year of Rameses II. have fallen in B.C. 1339? And if we cast up the three reigns, shall we not produce a sum-total of 124 years ? Unfortunate!}-, this is precisely what we may not do : and for the reason that Egyptologists, although agreeing as to the length of these various reigns, differ in loto as to whether they were consecutive or synchronous. If con- secutive— each Pharaoh succeeding to the throne upon the death of his predecessor, in regular order — then the three reigns would undoubtedly represent a period of 124 years ; but if synchronous — that is to say, if one Pharaoh began to reign during the lifetime of his predecessor, and counted his first regnal year from that date, instead of from the year when his predecessor died — then an entirely new calculation, resulting in a much-abridged total, will have to be made. Fairly stated both ways, the question stands thus : — 1. The XlXth dynasty began with Rameses I., who reigned six years, and who may, or may not, have shared his brief authority with Seti I., his successor. But Seti I., who reigned for fifty-one years, undoubtedly shared his throne with Rameses II. for many years before he died ; and Rameses II., more than half a century later, as cer- tainly took his own successor, Menephthah, into the same kind of roj-al partnership. Now, according to the syn- chronous theory, which is Brugsch's theory, Rameses II. dated his regnal year from the time of his association with Seti T. ; at which time Brugsch supposes him to have been about twelve or thirteen years of age. Some thirty, or thirty odd, years of his long reign of sixty-seven years would thus, it is maintained, be counted in with the reign of his father. If, therefore, accepting B.C. 1462 for the commencement of the XlXtli dynasty, we allow, in round numbers, thirty years for the joint sovereignty of Seti I. and Rameses II., we bring the beginning of the younger Pharaoh's reign to B.C. 1435 ; his accession to the un- divided crown to B.C. 1405 ; and his death, at the close of a reign of sixty-seven years, to B.C. 1368. Total of three reigns, from B.C. 1462 to B.C. 1368—94 years. 2. The advocates of the consecutive theory, as opposed to the advocates of the synchronous theory, found their argument upon the details of certain military campaigns wliich are clironicltd in the form of sculptured bas-reliefs and graven inscriptions upon the walls of various temples in Nubia and Upper Egypt. Here, at battles and sieges distinctly dated as having taken place in the fifth and eighth years of his reign, Rameses II. is represented accompanied by several of his sons, who, though evidently mere youths, are at all events old enough to take part in the thickest of the fight. That the king is liimself depicted in these tableaux as a man in the prime of life, cannot be accepted as evidence either way, since the artist would, of course, so represent him, no matter liow old or how young ho might be. But that a youth of seventeen or twenty should be tlie father of sons ranging from, at least, twelve to fifteen years of age, would be somowliat miraculous. If, however, wo suppose the monumental dates of the reign of Rameses If. to be counted from the year of the death of Seti I., tlien Rameses 11. would be thirty -five or forty years of age in ' the fifth year of liis reign, and old enough to be the father of a large grown-up family. This, at all events, is the opinion of Maspero, of Lenormant, and of the majority of French and English Egyptologists. Starting, therefore, with B.C. 1402, for the beginning of the XlXth dynasty, the consecutive theory brings up the reigns of Rameses I., Seti I, and Rameses II. to a total of 124 years. Beginning, as before, with the synchronous hypothesis, and holding fast to b.c. 1402, for the commencement of the XlXth dynasty, we will next see to what extent these dates correspond with the era of Nubti and the Hykshos calendar. {To he continued.) ENGLISH SEASIDE HEALTH-RESORTS. By Alfred Haviland, M.R.C.S., F.R.M.C.S. Lend. CLASSIFICATION {Continued from page 02). II. — As TO THEIR Position on tue Seaboard; whether THEY enjoy the WARM MOIST AlB FROM THE GULF STREA.M, TUE BRACING AlR OF THE NOBTH SeA, OR AN Atmosphere brought by the Winds after it has LOST ITS Sea character by passing over thousands OP SQUARE miles OF CONTINENT. THE Gulf stream, which has such a powerful influence on the climate, not oidy of our seaboard, but of the whole of the British Isles, must naturally claim the atten- tion of aU who really desire to acquire a sound knowledge of the cause of the exceptional high air temperature of our country within the interlatitudinal zones, described above, compared with that of other parts of the northern hemi- sphere lying within the same zones, but between different degrees of longitude to our east and west For the sake of clearness we may draw a distinction between the winter and summer temperatures of our atmosphere, inasmuch as their causes are distinct, although both are originally due to one grand cause — the sun. Our winter heat is an exotic, begotten by the sun-heat that pours down on the waters of the Gulf of ^Mexico, a large portion of which, as well as their point of issue, the Straits of Florida, lie under the tropic of Cancer. This sun-heat, tlius conceived by the sea, is transported in a north-easterly direction, by the vast marine current of the Atlantic, which owes its origin to the south westerly anti trade winds (our true south-west winds), to the Arctic regions, where, as it crosses the 80° of North latitude, its influence is still so great upon the atmosphere above it, between 70° E. and 10° W. long., as to create a mean annual tem- perature of 11° 22 Fahr., or an excess of 8° 96 over that of all other longitudes crossing the same parallel. Tlus same sun-heat, of which the Atlantic is delivered along th" whole course of the Gulf Stream, gives life, liealth, and vegetation to a large area of land, where, without its benign influence, the winter cold would kill, or make life diflicult to the weak and diseased. Tliis vast volume of warm water, the Korth-eastcrn branch of wliich, after its separation from the South- eastern at 47° N. lat., and 2.'>° \V. long, flows to the north and east along the coasts of Ireland, Scotland, and Norway, between Europe and Iceland, and, as Haughton remarks, probably extends beyond Spit/.bergen. The same author is of opinion that "this portion of the Gulf Stream owes its momentum to the .S'oi(//i-in>< niititniihs ; while the other, or South-eastern portion, is deflected by the earth's rotation to the south-east and south, and flows southwards along 110 KNOWLEDGE ♦ [July 1 i, 1882. the coasts of Spain and Africa until it rejoins the north equatorial curn^nt caused l)y the Xorlh-easI trades." It we take tlie mean of the ditTerent estimates of the magnitude of the Gulf Stream, as given by Maury, Herschell, Colding, Croll, and Thompson, we shall find, according to Haughton,* that nearly 38 (37-831) cubic mi\os of warm sea-water are transferred from the tropics to the north temperate zone per hour. This vast mass of sea-wator leaves the tropics at a tempei-ature not less than 6.')" FalL, and is cooled down to at least 40° Fall, in the temperate zone, ilaury estimates the rate of movement at five knots an hour. Sir John Herschell at four, Croll at four miles, and Sir Wyville Thompson! at three knots an hour. We have seen that this enormous volume of sea-water transfers heat from the tropics to the north teuipcratc zone, and tlien gives forth 2'>' of the 6.5° F. which it contained at its point of issue from the Straits of Florida. By the warmth thus brought from the southern latitudes, the British climate is upwards of 120° warmer, writes Buchan,+ in vittlcr than it otlierwise would be. Haughton, II in his paper on the effects of Oceanic currents upon climates, published in the Report of the Britisli Association for 1881 (York Meeting), has given much interesting matter on this subject. He there insists that the effect of the Gulf Stream upon our climate is limited to the winter, and that its effect on the summer tempera- ture is »i7. For instance, he shows that the mean temperatures of •January and July, the coldest and hottest months of the year, are as follows, taking the •")0° K latitude, which runs through the Land's End, Cornwall : — The mean January temperature at (Ivlf Stream lowfxtudeg is 4000° F., whilst at all oilier loiijilrtd-s it is 1H-28°F., or 1372° beluw freezing- point The mean Jul;/ temperature at Gulf Stream Jowji- I'ldes (Lat i")©' N.) is 03-80° F., whilst rt< all other longitudes it is 6-'r77° F., or lower by 1-97° F. ; and he concludes that the (Julf Stream adds nothing to the July temperatures of the localitie.s affected by it, but rather, on the whole, has the effet-t of slightly diminishing the summer heat. The general climatal effect of the Gulf Stream is, therefore, to make the annxuil ranfje of temperature less ; (the climate more insular), but it has no effect whatever upon summer heat or upon the fruiting of plants and trees that require a given July temperature for reproduction. The effect of the Gulf stream on the winter temperature of our Seaside Health-Rcsorts is most marked, and by the kind permission of Mr. Alexander Buchan, M. A., F.R.S.E., whose able works on meteorology are now so well known and appreciated, we shall be able to illustrate this most important part of our subject by giving his charts of Iso- thermals, together with tho.se promised in our last. It will theu be clearly .seen how each Health-Re.sort is affected, not only by the vnnter wnrmth of the sea, but by the sum mer hnal of the sun — the one temperature being exotic, whiUt the other is indigenmw. Ckvctat. PALAcr. — It in proponed by the Crystal Palace authoritica to organise an exhibition in tbc coming antamn anil winter, which shall inclodo both ffla and electric lighting. This is an excellent moTC, and one in the right direction. The great diffi- culty with which the anthoritieR will have to contend will, doubtless, l>c the mntaat j-alousics now go openly paraded. • Op. ci>. ^ "The Vi.yajfo of the Challenger: the Atlantic," vol. i., p. 371. (Xncmillan, Undon.) 1877. J " Introductory Text Book of Meteorology," by Alexander Bnchan, MA, F.R.S.K. (Blackwood, Kdinbnrgh.) i; p. 451. HOME CURES FOR POISONS.* VEGETABLE POISONS. TT7E may leave mineral poisons for the present, to >\ consider some which at the present season and during the next few months are more likely to be mis- chievous, .^viz., vegetable poisons. The most dangerous of these are the Hemlocks, including Hemlock Dropwort (J-Jnanthe Crocala), Water Hemlock (Cicuta Virosa), and the Common Hemlock {Conium Macnlatum), Fool's Parsley (^Kilnisa Cj/nnpiitm), Monks- hood (Aconitum Napellus), Fo.xglove (Digitalis J'ui-jmrea), Black Hellebore or Christmas Rose {Ilellehorus Niger), Buckbean (.Vcni/anlhes TrijnUata), Henbane (Ili/oscgamus Niger), Tliorn Apple (Datura Stramonium), and Deadly Nightshade (Atropa lielladonna), — to which may be added, though unlikely to bo taken in the same way, Cocculus Indicus (ilenispernum Cocculus), and Tobacco (Xicotiana I'ahacum). The Hemlocks and Fool's Parsley are UmbelliJ'era; and belong to the same order as carrots, parsley, celery, and parsnips. They owe their danger cliielly to their resem- blance cither in root or leaf to these kitc-Hcn-garden plants. Fool's parsley in particular has often been eaten by mistake for common parsley, from which, however, it may be readily distinguished by the black and shining surface of the under leaves, and their unpleasant smell when rubbed. All these four plants produce similar symptoms (Hemlock Dropwort in the most dangerous degree), viz., confusion of ideas, often terminating in delirium or stupor, coldness of the (ixtremities, and occasionally nausea and vomiting. Monkshood is a well-known garden plant, distinguished by its dark-blue, cap-shaped flowers, growing in clusters on a stem about three feet in height. The loaves are deeply divided, the upper surface dark, glistening green, the- under surface pale-green. The .symptoms produced are vomfting, convulsions, delirium, and stupor. There is generally no- ticeable swelling of the tongue and face, and tenderness of the stomach. 'The poison acts chiefly on the nervous sys- tem. According to Orfila, the juice of the leaves causes death in a short time ; the root is still more energetic in its action. Foxglove, though a wild plant, often finds a place in our gardens. Everyone knows its tall stems, and the purple flowers, shaped like a glove-flnger (whence its German name, Jingerhut). The leaves are dark-green, and rough. The symptoms of poi.soning by this plant arc lowering and intermission of the pulse, faiiitness, giddiness, and cold sweats, with hiccough and convulsion.s. The effect on the circulation is characteristic of tlie action of Digitalis ; it has been known to lower the pulse from 120 to 50 in a few minutes. It al.so has a diuretic effect. Black Hellebore is a dwarf plant, with deep-green leaves springing from the root. The flowers resemble those of the dog-rose in the numljer and shape of their petals. The symptoms are vomiting, giddiness, cramps, and convulsions. Bucklxjan, which is often gathered with the common watercress, may be easily distinguished by th(! leaves, which are always trifoliate, whereas the leaves of water- cress are divided into five or seven segments. Buckbean produces vomiting and colic, but seldom any serious mischief. • It is perhaps hardly necessary to point out that for decoction of tincture of Quinine in our last paper on this subject (p. 71, lino 7), decoction or tincture of Cinchona (or Peruvian Hark) should bo read. The correction should bo made in kHu, as iiIbo a few lines further on, where Quinine is again, by a printer's error, substituted for Cinchona. The decoction may 1)0 taken in doHCS rif a wine- glassful, at intervals of from half an hour to un hour, or the powder itself may l:(jlata, common ribwort, is by far the most abundant. It may be known by its long, narrow leaves, which rise from the ground nearly erect, as well as by its yellow stamens, and by the fact that each of its small, cup-like capsules contains only two seeds. When ripe, it divides in the middle, the top falling ofl' like a cover, and shows the two little kernels within. This is the most degraded of our inland English species, having completely accommodated itself to wind fertilisa- tion ; its petals are a dingy grey or brown, and are tucked away inconspicuously behind the calyx. /'. lutdia, the hoary plantain, is far less abundant, and much prettier. Though also mainly designed for wind-fertilisation, it has not entirely ceased to attract insects; and so its petals are still a faint whitish lilac, its stamens are tinged with pink or purple, and it has a slightly fragrant almond perfume. It may be known by its close rosette of broad, silvery white leaves, pressed tight against the ground in a bunch, so as to kill ofl" the grasses beneath it ; as well as by the fact that its capsule usually contains four seeds, at least in the young state, though one or two of them sometimes wither away before ripening. This is by far the prettiest of our Englisli species. P. /najor, the large plantain, is frequent along waysides. Its leaves are very broad, tapering into a stalk at the bottom, and less upright than in the ribwort. But the best distinctive mark is aflbrdcd by the capsule, which contains a number of very small seeds, as well as by tlie length of its spike, which is lower and longer than in the other species. This is also a very degraded kind, with small and very inconspicuous flowers, mostly concealed beneath their large green masking bracts. It is often given as food to canaries. The other two plantains are mainly seaside weeds. /'. roronopiig, the buckshorn plantain, has leares which sub divide into tines or branches, like a stag's antler, from which rough resemblance it gets its English name. Its tufted stock, with a ring of narrow, much-branched foliage, is familiar to everybody on cliffs and pastures by the seashore, as well as on sandy places inland. Its leaves lie flat against the earth, showing ofl' their tracery-work most delicately on the pale background of a sand-patdi. The flowers are very inconspicuous, with brownisli stamens, and the calyx is fringed with minute hairs. There are four cells or divisions in the capsule, but the seeds seldom all ripen. 7'. marilima, sea plantain, is the least interesting of any. Its leaves are long and slender, but very fleshy, something like thick green cords; and its flowers are almost as minute as those of the buckshorn plantam. The capsules have only two seeds. This is the most 11 KNOWLEDGE [Ju, 1882. I. ijnuled spoeiea of all, its flowers being quite uuiioticeaWe, owing to their greenness or brownness, and it is apparently always wind-fertilised Nevertheless, all of the plantains are originally descended from ancestors with bright petals and honeyed nectaries, as may be seen by their united corolla, which inyariably points back to an earlier stage of insect fertilisation. /'. tncdia shows us best what is the sort of type from which these degenerate little weeds are ultimately derivesia Quadra), and Common Footman (L. Complanula) are now on the wing. The six Belted Clearwing {Scsia Ichnrmnoniformis), VTood Swift {;/i'pi"a?KsSy!i»inMs), Short-cloaked Moth {Nnla CucitUntella), Muslin Moth (Arclia ifendica). Cinnabar {Euchelia Jacohim:), Brown Tail (Liparis Chrysnrrhea), Gold Tail (L. Anrifiua), Satin Moth (i. Si- IMs), Gipsy {L. Dispar), Black Arches {L. Monacha), Lackey (^Bombyx Neustria), and Oak Eggar (B. Qucrcus) should all be «ought for during the course of the month. Among the Geometr.*:, we may expect to find the Swallow-tailed Moth (Vropteryi Sambucata), Bordered Beauty (Epione Apiriariu), Little Thorn (IJ. Advenaria), Earlv Thorn {Selemia Illunaria), Dotted Carpet (dlo'ia Glabraria), Mottled Beanty (Bnannia R'pan- ' '•), Common Wave (Cabera Exanthemnria), Common White ■ ivc (C. I'limria), Clouded Magpie (Abraxn.'! Ulmata), July High- r (YpsipetcK Eiulafa), Common Carpet (Mclanippe Sublrislata), "St of tho " Emeralds," and the Scalloped Oak (Crocallis Elin- ■ivaria). The NocTU.E that fly this month ate far too numerous to mention, but amongst others we may expect to find tho following :— Tho Buff Arches (Gonnphora Dedrasa), Peach Blossom (Thyalira Balis), Marbled Beauty (Bryophila I'erla), Brown-line Bright-eyo (Leucania Conijura), Common Wainscot (Leucania palUns), Dark Arches (Xylophasia polyodon). Bordered Gothic {Neuria Saponariac), Straw L'ndcrwing {Ceriyo Cytheria), Dot Moth (Mamestra persicarioe) , Garden Dart {Agrotis nigricans). Gray Arches {Apleefa nebulosa), Marbled Clover (Heliothis dipsaceus), Golden Y (Phisia Iota), Burnished Brass (P. chrysitis), Broad Bordered Yellow Underwing (Trvphaina fimbria). Large Yellow Underwing (T. pronuba), and the Old Lady {Mania Maura). On the 2Sth ult. I had a Death's Head Moth {Acheroniia afropos) brought to -me by a farm labourer, but I am sorry to say it was in a very damaged state, though still alive. Have any of our readers heard of this insect appearing so early in the summer .' FIRE RISKS FROM ELECTRIC LIGHTING. rpiIK following rules and regulations for the prevention of fire J_ risks arising from electric lighting have been recommended by the Council of the Society of Telegiaph Engineers and Electricians, in accordance with the report of the committee appointed by them on May 11, 1SS2, to consider the subject : — The members of the committee were — Professor W. G. Adams, E.E.S., vice-president, Sir Charles T. Bright, T. Knssell Crampton, R. E. Crompton, W. Crookes, F.B.S., Warren De la Rue, D.C.L., F.R.S., Professor G. C. Foster, F.R.S., past president, Edward Graves, J. E. H. Gordon, Dr. J. Hopkinson, F.R.S., Professor D. E. Hughes, F.R.S., rice-president, W. H. Preece, F.H.S., past presi- dent, Alexander Siemens, C. E. Spagnoletti, vice-president, James N. Shoolbred, Augustus Stroh, Sir William Thomson, F.R.S., past president, Lieutenant-Colonel C. E. Webber, R.E., president. These rules and regulations are drawn np not only for the guidance and instruction of those who have electric lighting appa- ratus installed on their premises, but for the reduction to a minimum of those risks of fire which are inherent to every system of arti- ficial illumination. The chief dangers of every new application of electricity arise mainly from ignorance and inexperience on the part of those who supply and fit np the requisite plant. The difficulties that beset the electrical engineer are chiefly internal and invisible, and they can only be effectually gnarded against by " testing " or probing with electric currents. They depend chiefly on leakage, undue resistance in the conductor, and bad joints, which lead to waste of energy and the production of heat. These defects can only be detected by measuring, by means of special apparatus, the currents that are, either ordinarily or for the purpose of testing, passed through the circuit. Bare or exposed conductors should always bo within visual inspection, since the accidental falling on to or the thoughtless placing of other conducting bodies upon such conductors might lead to "short circuiting," or the sudden gene- ration of heat due to a powerful current of eleetricity in con- ductors too small to carry it. It cannot be too strongly urged that among tho chief enemies to be guarded against are the presence of moisture and the use of " earth " as part of the circuit. Moisture leads to loss of cnrreot, and to the destruction of the conductor by electrolytic corrosion, and the injudicious use of " earth " as a part of the circuit tends to magnify every other source of difficulty and danger. The chief element of safety is tho employment of skilled and experienced electricians to supervise the work. I. The Dynamo Machixk. 1. The dynamo machine should be fixed in a dry place. 2. It should not be exposed to dust or flyings. 3. It should bo kept perfectly clean and its bearings well oiled. 4. Tho insulation of its coils and conductors should be perfect. 5. It is bettor, when practicable, to fix it on an insulating bed. (). All conductors iu the dynamo-room should bo firmly snp- ported, well insulated, conveniently arranged for inspection, and marked or numbered. II. TiiK Wires. 7. Every switch or commutator used for turning the current on or off should bo constructed so that, when it is moved and loft to itself, it cannot permit of n permanent arc or of heating, and its stand should bo made of slate, stone ware, or sorao other incom- bustible substance. 8. There should bo in connection with the main circuit a safety fuse constructed of easily fusible metnl which would bo mcltod if the current attain any undue magnitude, and would thus cause tho circuit to be broken. 9. Every part of the circuit should be so determined that the gauge of wire to bo used is properly proportioned to the currents it will have to carry, and changes of circuit, from a larger to a smaller 114 KNOWLEDGE [Jl'LV H, o'nJuctor. should bo scfficii^ntly protcotcil witli suitalilo safety fasps. so that no portion of the conductor should ever be allowed to attain a tempcrntnre ciceedinp 150 dog. F. X.B. — These fuses ore of the very essence of safety. They should aln-ays be enclosed in ineonibustiblo cases. Even if wires become perceptibly warmed by the oniinnry current, it is a proof that they arc too small for the work they have to do, and that they ought to be replaced by larger wires. 10. Under ordinary circumstances complete metallio circuits should be used, and the employment of gns or water pipes as con- ductors for the purivose of completing the circuit should in no case be allowed. 11. Where bare wire out of doors rests on insniatiug supports it should be coated with insulating mntoritil, such as intlia-rubbor, tape, or tube, for at least two feet on each side of the support. 12. Bare wires passing over the tops of houses should never bo less than 7 ft. clear of any )iart of the roof, and they should in- variably be high enough, when crossing thoroughfares, to allow firo escapes to pass under them. 13. It is most essential that the joints should bo electrically and mechanically perfect. One of the best joints is that which is whip[>e|>o