"to Ijlre&enteb to of the of QTormtia William Lash Miller, B.A.Ph.D«C.B.E. GALLERY or NATURE AND ART; Otl, A TOUR THROUGH CREATION ANDUBCIENCE. BY THE REV. EDWARD POLEHAMPTOX, FELLOW OF KING'S COLLEGE, CAMBRIDGE } AND •"XM. GOOD, F. R. S. EDITOR OF THE PANTOLOGIA, &C. IN SIX VOLUMES, ILLUSTRATED WITH ONE HUNDRED -ENGRAVIHGS,. DESCRtPTtt'E OP TOE WoNDKRf OF JV I 7 t' R£ ^.VC ART, SECOND EDITION. VOL, VI. LONDON : |3 • PRIXT-ED BY R. WILKS, CHAXCERr-LAKF : BOLD Br BAI.PWIV. K, \ynjOY, PATJ.HVOSTEU-ROW ; !t. AKU CO. i \|)I '.it ivcoll, 11 . ; BTRAXT) ; III M)'CS, IIOI.IiOHX -li U1S ; (I.AKKI. AXD :l BOOKStLI.tUS. INDEX. A.BA SO, description of the baths of, 1.1, Aberdeen, remarkable storm at, iv.SIS Aberration of the iixcd stars, disco- very of, i, 33 Abyss, on the great, i, 252 Abi/ssinia, mountains in, ii, 429; on the rains of, iv, 141 ; winds in, 189 Academy of sciences, institution of the, Acid, on the atmospheric carbonic, iv, 19 Acidulous waters, analysis of, iii, 183 Aconite, experiments with the juice of, v, 230, 236 Acroteri, account of the isle of, i, 497 Actinia, or sea anemone described, v, 36;} — • Adlersbcrg, remarkable cavern at, ii, 79 Adrian, remains of the villa of, iii, 63 JErial globes, how made, vi, 238 .•Krolites, remarkable shower of, iv, ; general history of, 468 ; ana- l\sis of, 470; origin of, 475 JErostalion, principle! of, vi, 03 ; his- torical account of, 64 /Es, on the antient, vi, Affinity, nature of chemical, vi, 132 Africa, volcanoes of, i, 407; metals and ores or', ii, 292 ; mountains of, 428 ; ou the rivers oi', iii, 1.5 ; deserts of, ii ,483; on the climate of, iv, 82 Agaric, the cause of fairy-rings, v, 318 Agates found in Scotland, ii, 326 ; note. .\ij.Kino, account of the lake of, iii, 242 Ai/rinila, George, character of, vi, 9 Air, on the properties of the, iv, 4 ; instruments for measuring the, 8 ; remarkable lights in the, 400, ! Hi Aix, account of the bnths of, iii, 169 A ijc-la-ckapelle, mineral springs at, iii, 106 Aliltttbaalis, caravans so named, ii, 484 Albtrtl, aflrcting story of, ii, 333 Alchemy, antiquity of, vi, 5 Alcohol, experiments on, v, 226 Alexandria, ac< mint of the school of, i, 9 ; the stadium of, 1 1 Alleghany mountains described, ii, 43 1 Altier, St. remarkable bridge of, iii,l<>9 Alligator, description of the, v, 550 VOL. M. Alluvial formations of the earth, i, 326 Almicanters, definition of, i, 307 Almonds, on the essential oil of bittrr, v, 229, 236 Aloes tree described, v, 191 Alphabets, invention of, vi, 351 Alphotiso of Castile, account of, i, 19 Alpine plants, account of, v, 34 Alps, general description of the, ii, 410 waterfalls in the, iii, 219; red snow onlhe, iv, 173; passage of I latin ibid over the, vi, 173 Alum collected in Solfatara, i, 520 Amazons, description of the river of, iii, 45 Ambergris on the coast of Ireland, ii, 177 ~%meriea, volcanoes of, i, 479 ; metals and mines of, ii, 292 ; mineralogy of north, 313 ; mountains of, 431 ; rivers in north, iii, 33 ; in south, 44 Amianthus, description of the, ii, 392 Ammoniac, on caustic, iii, 190 Ammoniaemn, properties of the gum, v, 208 Ammonian fountain, its existence prov- ed, iii, 140 Amnhilials, particulars of, v, 542 Amphiscii, what, i, 313 Amphitheatre of Vespasian, account of, iii, 67 Amsterdam, description of the isle of, iv, 102 Analysis, observations on mathemati- cal, i, 176 Anaxagoras, system of, i, 7 Ann.fhnander, maps conutructed by, i, 298 Andes, remarkable caves in the, ii, 81 ; (IcM-ription of, -l.il ; temperature of the, iv, 61 ; rain in, 149 Ant/If set/ copper-mines, account of the, i'i, 318 A in/ n.\t lira bark, account of, v, 158 Animalcules described, v, 3 15 Animals, characteristics of, v, 1; classi- fication of, v, Anio, scenery on the river, iii, 67 Ant, natural history of the, v, 449; «C-> count of the vliite, ib. 171 Antartic circle, voyages to, iv, 89 INDEX, Anthony, df tlic l.ilK lit" St. in, A>itiutl> ill >lm\cd l)\ f.trlliiiuaki >, ii, J .tnti/i, -Hoof, ii, 77 .lnti,nnle.\ drh'neil, i, .1 1 i .4iiliii>iitirf fomiil in l.incoliuUire, ii, JI7 i Yorkslun •,•-',' 7 ; I Irrrulaiirmn, . Pomp, ii, i48; Industri:* LeMcnhatt-ctrect, An lisa no, volcano of, i, (;>*) Antirci, ilriiiiitinii of the, i, 314 Antrim, curiosities of, i, 271 Apes hills in Afric ;i described, ii, 4~'8 A]i]>allachian mountains described, ii, -431 A}>i>rn>iiiirf, deHTiption of, ii, 418 ; lu- minous appearance of the snow m, iv, 501 Aquatic plants, v, 23 Arabia, deserts of, ii, 483 ; heat in, iv, 7S j rains seldom in, 156 Arabians, astronomy of, i, 19 i know- ledge of chemistry by the, vi, 6 Ararat, situation of mount, ii, 424 Arches, luminous, iv, 421 ; iridiscent, ii>. Archimedes, account of, vi, 458, 46.5 A ichitectnre, on the science of, vi, 465 ; on naval, ib. 513 Antic circle, climates \\illiin, iv, 111 Areca nut, account of, v, 60 jtrutan-hiis, account of, i, 16 Aristotle, physics of, i, 216} on mea- suring the earth, 299 Ark of Noah described, vi, 513 Arrows, poisoned ones of the Indians, v, 267 Arts, on the imitative, vi, 408 Arvo in Savoy, scenery of the, iii, 220 Arzilain Barbary, earthquake at,ii,41 Asbestos, account of the, ii, 391 Atcii, definition of the, i, 313 Athet, account of a shower of, iv, l6l Ashli/, Northamptoushirc, storm at, iv, Alia, population of, i, 316 ; volcanoes, 4"i, mines of precious stones, ii, ; , mountains, 423 ; rivers, iii, 10 Aiphallittf, description of the lake, iii, A*i>haltnm,s\H;nfif gravity of, iii, 151 j i \\« i-itnriiU on, ib. 254 Atpic of Cleopatra, ou the, y, 580 .\ssn-fii I i-.l i |>l:i!it (Irsrribril, v, | •( ion of, V, SO4 Attrolwn/, origin of, i, 4 .\\ti-iniiiiiiii-i'l .-ymbols cxjil.iiiu'i1 Astronomi/ of tin- untu-nts, i, I dern i;uro|»o, 19 j general n on, 34; elements of, 144, g< remarks on, 1H9 ; future proyi- 806 Atheism, observations on, i, 215 Athens, sculpture and architecture of, vi, .•>K> .1/A/t.v, description of mount, ii, Atlantic ocean, observations on, . Atlas mountains described, ii, 428 Atmosphere, observations on the solar, i, 51; of the earth described, ib. l.) • ; general nature of, iv, 2 ; vari- ation, 24; elasticity, 2.r) ; ten- ture, 31 ; currents in, 1'j? i f»M» ot" the electric, 271 : shower of ston«->. from, 459 } refractions in, .-"> Hi Atmospheric air, observations on. iv, 4 ; water, ib. 14; carbonic acid, 19 » unknown bodies, 21 ; electricity, 297 ; deceptions, />(>4 ; refraction, singular instance of, 514 Attnnicul system of physics, i, 216 Atropn bcila donna, properties of, v, 980 Attraction, on the principle of, i, 221 ; of electricity, vi, 18; nature of che- mical, ib. 132 Avalanches, accounts of, iv. 175 Avernns, description of the lake, iii,6l Aurora borealis, as seen in Hudson'* bay, iv, 117 ; general history of the, ib/393 Australasia, on the name, i, 316 Aiitiiii, a remarkable wiud so called, iv, 234 Azores, volcanic phenomena in the, i, 497 ; island thrown up there, ib. 502 Azotane, account of, vi, 207 Azotic gas, what, iv, 6 Bacon, Roger, character of, v i, 7 ; his discoveries, ib. 170 Baden, description of the baths of, iii, 163 Baia'e, scenery and antiquities of, ui,57 Baikal lake iii Siberia, iii, 231 INDEX. J!«la, description of the lake of.iii, 241 Balaclava, in the Crimea, described, ii, 453 Jiulbeck, temple of Ildiopolis or, vi, H'7 Baldu-iii, Mr. liis aerial voyagr, vi, 7(3 Balloons, construction of, vi, 80 Halls, account of blazing, iv, 42.5 ; ob- servations on fire, ib. 460 Balsam tree, description of, v, 77 Jiultic sea, on the waters of, iii, 312 Banana tree, described, v, 53 Banian tree, account of the, v, 45 Banks, Sir Joseph, anecdote of, iv, 87 Baobab, or calabash tree, described, v, 61 Barbadoes, remarkable caves in, ii, 81 Barbary, earthquakes in, ii, 40 Bordello, site of the antieut, iii, 73 Bark, different kinds, v, 146 Barometer, principles of, iv. 25 j de- scent of, 143 Barrows, account of, vi, 506 Basaltcs of Vesuvius, i, 354 Basaltic hummocks described, i, 293 ; columns, general account of, ii, 471 B*tavia, unhcalthiness of, v, 84 Bath, description of the city, iii, 171 Baths, inchuntcd ones of Africa, iii, 162 Beccher, his character, vi, 11 Bee, natural history of, v, 421 Beech, letters found in one, v, 314 Beet root, mode of extracting sugar from, v, 86 Bejncos, peculiar bridges in South America, ii, 436 Belemnites, description of, ii, 151 Bell metal, composition of, vi, 286 Ben y ore, description of the promonto- ry of, i, 273 Beni Abbess, in Algiers, described, ii, 428 Besaiifon, remarkable cavern near, ii,82 Besselrif yhant in India, described, ii, 447 Bethesda, observations on the pool of, iii, 142 Beuly Frith, in Scotland, described, iii, 273 Birds, classification of terrestrial, v, 337 ; aquatic, 338 ; natural history o£ v, 585 ; migration, 640 JBifKmiwMf fountain at Cracow, iii, MM Blackbird, natural history of, v, 623 Black jack, ou the properties of, vi, ] 4, 246 Blanc, height of Mount, ii, 411 Blancliard, the oil-rial voyages of, vi, 71,— 77 lllastinf/ rocks, method of, ii, 273 Blende, nature of, vi, 246 lilind persons, their quickness of per- ception, iv, 545 Blue colour of the sky, cause of, iv, .0 — — mountains of Jamaica described, ii, 433 Boa, description of the great, v, 573 « Bogs in Ireland, description of, ii, U'4; origin of, iii, 226 llohan Upas, on the, v, 279 Bo/^iu^-springs, general account of, iii, 104 Bolognian stone, properties of, ii, 385 ; phial, nature of, vi, 167 Bolsena, cape, describee!, iii, 241 Bombs, construction of, vi, 238 Bvnes, account of remarkable, ii, 152; enormous ones in Siberia, 178; fos- sil, 1 82 ; general history of, 1 89 ; is- lands formed of, 195 Bonoiiitt, remarkable light seen at, iv, 418 Bvrrotcdale iu Cumberland, described, iii, 261 Borysthenes, present state of the, iii, 2 1 Bostonin America, earthquake at, ii,44 Botany, particular divisions of, v, 1 j systems of, 6 Bothnia, temperature of the gulph of, iv, 33 Bourbon, volcanoes in the isle of, i, 477 ; river in America, iii, 39 Bonrget in Savoy, lake of, iii, 236 Botey coal, origin and properties of, ii, 339 Boy It, anecdote of, vi, 8 ; character, ib. 10 ; discovers phosphorus, ib. 1 13 BrachwuHs, visited by IMhngoras, i, 7 Bradley, Dr. discoveries of, i, 33, 43 Braminx, astronomy of the, i, 34 Brass, preparation of, vi, 260; of the autients, on the, ib. -•? .' Braybrook, Northamptonshire, storm at, iv, 453 Brazil, mineral productions of, ii, 302 ftj INDIA'. trre clrsrribrd, v, 1,1 ; of tli. !!•.: Jirffzrt, on sea ami land, i ;>!»•, destruction of, iv, Bridget, remarkable ones in South Ameri •, u, ' .;<>; natural one in Vir- ginia, il itraordinary one ;it >•. !i ..I'haiiscn, ni, ~'l; long one over the i . at Paris, SO; of Allier, 169; of bo.;t*, vi, 517; ruinous ones, llrittnl wells, description of, iii, 174 Britain, metallic mines of, ii, 31H Sri-rham, Devon, remarkable well at, iii, 85 Bronze metal, composition of, vi, 280 Broselu, boiling well at, iii, 148 Bronahton, in Lancashire, quarries at, ii,U9 Tludit, warm baths at, iii, 168 Buenos Ayres, the mines of, ii, 296 Biijf'on, singular hypothesis of, i, 208 Buildings, how to preserve high, iv,308 Bnlial, natural history of the, v, 588 Bull-ffflit, description' of, v, f>79 Bull-finch, natural history of, v, 628 Burkhardt, Prof, his observations, i,l30 Unmet'* theory of the earth, i, 255 Burthens, force of moisture in raising, iii, 4 10 Butter-dew, phenomenon of the, iv, 152 Butterfly, natural history of, v, 400 Buxtw: wells described, iii, 170 Coder Idrit in Wales, height of, ii, 442 Cadiz, earthquake at, ii, 39 Caiar, his survey, i, 301 Cajcput tree, on the oil of, v, 209 (.':d not, account of, vi, 51 1 • ith tree described, v, 51 ( 'alc.bria, earthquakes in, ii, 3,62,72, Calais and Dover, union of, iii, 301 Calamine, properties of, vi, 263 ; ob- servations on, ii, ~2l '") Calamus, properties of, v, 169 Calf ', the art of, vi, 437 Caldeira of St. Michael described, iii, 114 Calendar, reformation of, i 14 i . observations on the golden, vi, 4 to ill South America, destroyed, ii, 9 • i i.d, wliirl- \\ifiil at, iv, i . description of a rrmurkai Camps, anticnt Roman, ( 'antida, heat, and cold in, iv, .:••, n»t< . Canal, the 1'Yenrh rmal, iii, .; nrirkable ones in l,ng!a ('anti/x, on the eonstructioii of, iii, 379 Canella tree, described, v, Cannon, on the making of brass, vi, 286 Canari/ bird described, v, 631 Canaries, volcanoes in the, i, 469 » re- markable cave in, ii, 80; vines of, v, 74 Canterbury cathedral, experiments on the tower of, i\ , 67 Caoutchouc, properties of, s. Carbonic acid, nature •>,, \\ Cardamon tree, described, v, 2o(i Capillary tubes, observations on, iii, Ki? Carmarthenshire, storm in, iv, ,'H(J Carpathian mountains, beightlof,ii,409 Carp, natural history of, v, Cascade on the Anio, iii, 66; marble, 219; i» Dalmatia, '2i\ ; Yordaa ni Yorkshire, 223; of (ilamma. Lawdoor, 26 1 CasearillOf properties of, v, 1 ."> I Caspian sea, description of the, iii, 23 1 Cassava tree, description of, v, .r> I Cassini, account of Dominic, i, 32 Cassia tree, description of, v, 140 Cassowary, description of the, v, 6l6 Castletoiiiit Derbyshire, described, ii,su) Cantor, on the changes of the star, i, 1 1:3 Castor in Norfolk, anticnt camp at, ii, 821 Catania in Sicily, destroyed, ii, 6 Cataracts of Scumander, iii, 51 ; the Nile, 213 ; Niagara, '> 1 :> ; I survey of various, 2 19 ; at ScarThau- sen, 221 ; in Norway and Sweden, 222 ; Lidford in Dcvon.il> ; in Cum- berland, 224; on the Shannon, ik ; in America, c_ Catulluss villa, site of, iii, ? 1 Caucasus, description of the mountains of, ii, 424 Causeway, account of the giant's, ii, t; .> INDEX. Causeways, on basaltine, ii, 47 1 Cavendish, Mr. experiments of; iv, 9 Carcrns, brief sum- v of foreign, ii, 76; remarkable ones in Mn^b.nd, ib. 83; Ireland, 94 ; in the 1 lebrides, 96 ; at Paris, 1 13 ; in the Crimea, 46o ; Gi- brultar, 4d4 , ou the utility of, vi, 15 Cax-npore, heat at, iv, 7 "> Cajctoti, \Viiiiam, account of, vi, 405 Celano, description of tJie lake, iii,, 63 Celestial worlds, conjectures on, i, 36 ; organization of, i, Ol Crnis, mount, niethoJ of passing, ii, 413; description of, ib. 415 Cerastes, or hooded snake, account of, v, 577 Cerigo, earthquake at, ii, 21 Ceylon, land-winds in, iv, 219; ele- phant-hunt in, v, 65* ; trade of, v,128 Chtetodon, natural history of the, v, 512 Chaldeans, their astronomy, i, 3 Chanueleon, natural history of, v, 552 Champlain, description of lake, iii, 247 Chapman, Capt sweetens sea-water, iii, 370 Charcoal, identity of diamond and, vi, 150 Charles, Mr. his aerial voyages, vi, 70 Cheddar cliffs, Somerset, described, ii, 90 CheltenJiam, description of, iii, 175 Chemical affinity, nature of, vi, 132 Chemistry, rise and progress of, vi, 1 ; in its infancy, 12 ; uses of, 13 ; pro- posal for the improvement of, 15 Cherry laurel, qualities of, v, 246 Cherso island, description of, iii, 237 ChesapeaJt bay described, iii, 43 Cheshire rock-salt, account of, ii, 369 ; remarkable storm in, iv, 182 Cheviot hi! is, description of, ii, 441 Chimborar-o in South America, describ- ed, i, 490 China, antiquity of astronomy in, i, 5 ; account of the sonorous stones of, ii, 686 ; mountains, 427 ; rivers, iii, 12 ; cotton tree, v, 284 ; cultivation of .is, v, 10,'; wall of, vi, 480 Chinese, their astronomical claims dis- puted, i, 34 ; tradition of the delude among the, 248 ; white copper, vi, 279 ; tire, how to make, \ i, j 1 1 Chios, famous for its wines, v, 75 f'lilnriiie, experiments on, ii, Christopher, hills in the isleof St. ii, 433 Churchill's river.cflects of cold in,i v, 1 14 Cinnamon tree, account of, v, 119 Ciitlra mountain described, ii, 4^1 Circles on the globe defined, i, 306 Civita Turchiimo, ruins at, ii, 258 Classijication, systematic, v, 5 Cleopatra, death of, v, 580 Climates, division of, i,312; varieties, iv, 42 : effects ou vegetation, v. 19 Clitiimniis, source of the river, iii, 53 Clot ks, sympathy in the action of two, iv. 547 Cipiuls, on the solar, i, 53 ; formation tof, iv, 143, 146 Cppmif phenomenon seen in the vale of, iv, 530 Coal, nature and origin of, ii, 324 ; ap- plication of gas from, vi, 89 mines, of England, ii, 279 ; Ame- rica, 316; Scotland, 324; Ireland, 329 ; general description of, 337 i accidents in, 344 Cobra de Capello described, v, 584 Cobham in Surrey, agitation of water at, ii, 50 Coca plant described, ii, 296 Cochineal insect described, v, 396 Cocoa tree, description of the, v, 118 Cod-fish, description of, v, 504 Coffee tree described, v, 106; how to use, ib. 109 Cold, effects of severe, iv, 86 ; in Hud- son's bay, 114; at Glasgow, 121 Ooldstream in Scotland, storm at,iv,33O Colebrooke dale, description of, ii, 322 Cole's cave in Barbadocs, described, ii, 81 Coloqnintida described, v, 203 Colosseum of Vespasian, site of, iii, 6? Colossus of Rhodes destroyed, ii, 3, vi, 500 Columbo, temperature at, iv, 75 ; de- scription of the root, v, 205 Columbus, voyages of, iii, 44 Columns, account of basaltine, i' Combustion, on spontaneous, vi. 128 Comets, doctrine of Pythagoras on, i. 8 ; observations on that of 181 1, 114; construction of the same, 130, 132 ; passage of, 138 ; deluge ascribed to INDEX thr infliien. < <>f "I"1, '2"'?; use* of, . ,.n ilirs'.j.-n T.^m. \ inthepro- dnction of, i, 135; ^cnci.il remarks on, 1 11 <'"-«. --Hi-ulMr i Hi < t of thunder and lightning on at sea, iv, 348; <,!», n.ilions on, .i.>(); funnatioii of, SOS; vari lion of, 377 <;,m!-, description of, vi, 40 Condor, natural history of, v, 585 Conductors, description of electric, iv, 308 Congelation, tables of, iv, 37 Connecticut river described, iii, 43 Constance, description of the lake of, iii, 233 Coiiftantia wines, description of, v, 73 Constellations, on the names of, i, 3 c mi tit $ ion, method of destroying, iv,23 CooA/Capt. his voyages, iv, 87, 94, 106 ; death, 1 12 Copaiva tree, balsam of, v, 183 Copal varnish, how made, v, 293 Copernicus, account of, i, 20 Copper, mine of, in Wicklow, ii, 277 ; Japan, -288; America, 314; Angle- sey, 318; Cornwall, 321 ; Ireland, 328 ; experiments on, vi, 263 ; Chi- nese white, vi, 279; method of tin- ning, 295; plating and gilding, 312 Coral, production of, ii, 277 ; formati- on of islands of, iii, 298 ; varieties of, v, 353 'leratm South America, describ- rd, n, I,'! 1 Corne-ubbas, Dorset, whirlwind at, iv, 151 Cornwall, earthquakes in, ii, 55 ; tin- works in, .'i'20; copper-mines, 321 ; storms in, iv, 320, 324 Corpitsculixtt, their doctrines,!, 217 Cotopajri in South America, dex.-np- tion of, i, 485; its height, ii, 434 Cotton plant, natural history of, v, 283 CourantiiKs, or fixing rorkcts, how to make, \i, 231 Crab*, description of, v, 481 Cracow, description of the salt-mines •1 ; bituminous foun- tain at, in, i l!» Cranbrook in Kent, phteiioincuon at, ii, 61 , on tin* Mosaic iicciiunt, Crrmnitz, gold mines of, ii, CIT.V.»I/, cannon IIMM! at Hie battle of, vi, 169 Crete, labyrinth in UK- isle of, ii, 7? Cricket, natural historx of, v, ,,!il Ci-iiHia, curiosities in tiie, ii. Crocodile, natural history of, v, Cromlechs, account of, vi, Crows, the migration of, v, • Cn/slulliztttion, sjstesn of, n, Cn/stallof/rai>lii/, nature of, \ i, 1 12 Crystals of snow, on, iv, 1 ( it i Cm Into, natural history of, \ . Cumberland, lakes 01, iii, 243, 260; tempest in, iv, 24(i Currents, observations on under, iii, 352; velocity of, 392; atmospheri- cal, iv, 185 Cuttle-fish, description of, v, 357 Cyanometer, its uses, iv, 5 Cycas, or sago tree, account of, v, 59 Cycles and eccentrics, hyphothtsis of, 'i, 1.5 Dagenhatn, Essex, inundation of, ii, 147, 154 Daillie, Dr. voyage of, iv, 105 Dalmatiu, gold in, ii, 284; remarkable cascade in, iii, 221 Dalton, Mr. his discoveries, iv, 10, 18, 130 Dambea, in Ethiopia, lake of, iii, 231 Damp, in mines, observations on, ii, 346 ; its effects on hay ricks, iv, 502 Dantzic, effects of a storm at, iv, 312 ; mock suns seen at, 521 Danube, description of the, iii, 22 Date tree, description of the, \, <>.; Datura stramonium, properties of, v, 868 Davy, Sir II. his discoveries, vi, 16 Dead sea, description of the, iii, 253 Death watch, described, v, .S?H Deceptions, on atmospheric, i\r, 504 Dee, source of the river, iii, v 1 1 Deeping fen, Lincolnshire, water spout at, iv. 269 Deers horn, found in an oak, v, 315 Delfforicia, scite of the ancient, ii, £23, 226 Deluge, history and opinions of the, i, 845 INDIiA. Denbigh, \iolent Ktonn at, iv, !;»."> Derbyshire, pir.i'iiomenon in tlie Icac mines of, ii, -M>; natural wonders at the peak of, il>. >-S; springs and folia- tains in, iii, 1713 ; lunar rainbow in, i\ . .vjo Dtnrnit \>ul; r, description of, iii, '243 Descartes, hypothesis of, i, H>8 ; ou tht doctrines of, ib. 21(>, -22O Deserts, of Arabia, described, iv, 78; of Afrii'a, si Desiynint/, on the art of, vi, 408 Detonating substance, vi, 207 Deucalion a Hood, observations on, i, •247 DfriCs hill, at the Cape of Good Hop«, ii, 430 hole, Derbyshire^jlescribed, ii. mill, in Ireland, iii, 430 Devonshire, shocks of an earthquake felt in, i, 54 ; remarkable well in, iii, 85 ; cataract in, 222; storm in, iv, 317 Dew, on the formation of, iv. 139 ; but. ter like, 152 Diamonds, on the discovery of, ii, 270 ; specific gravity of, 27 1 ; on the seat of, -275 ; of Golconda, mines of, 289 ; remarkable ones, 291 ; of Brazil, 302 ; description of Cornish, 322 ; on the nature of, vi, 149 Distillation, examination of mineral waters by, iii, 204 Dodotias spring, account of, iii, 144 Dole, in Switzerland, view from, ii, 412 Domes, account of whispering, iv, 533 Don, description of the river, iii, 21 Douce, in France, ice house at, ii, 82 Dover, communication between Calais and, iii, 301 ; remarkable welJ at, iv, 73 Dragon t wood or calamus, described, v, 169 Drawing, origin of, vi, 408 Drome, disappearance of the river, iii, 9 Dropping well at Kuaresborough, iii, 283 Druids, on the temples of the, iv, 376 Duck, natural history of the, v, 645 i-kill, a remarkable quadruped, Ducks, in the lake of Zirknitz, de- scribed, iii, 103 Dndlcu, Mr. on embankments, iii, 377 Dittany, M. discovers the detonating substance, vi, 207 park, Ireland, curiosities of. , description of, i, 293 Diist, account of a shower of, iv, 161 Dykes, in Holland, description of the, iii, 286 Dwiita, description of the river, iii, 2! Eagle's eyrie, in Cumberland, iii, 265 Earth, ancient measurement of the, i, 10; astronomical elements of the, i, 152 ; general structure of the, 230; cause of inequality on the, 27 1 ; ge- neral description of the, 296 ; me- thod of measuring the, 299 ; form of the, 302; superficial phenomena of the, ii, 394 ; on the temperature of the, iii, 107; structure of the in- ternal parts of the, iv, 377 Earthquakes, cause of, i. 330 ; general history of, ii, 1 ; chronological list of, 12; ascribed to electricity, 13; great one at Lisbon, SI; various, 45 ; in Iceland, iii, 137 Eartlis, obsen atioiis on metalline, ii. 26? East Indies, effects of lightning in, iv. 343 Ebro, course of the river, iii, 31 Echoes, observations on, iv, 542 ; re- markable, 546 Eclipses, ancient account of, i, 3 ; the doctrine of, ib. 164 ; of the satellites, 202 Ecliptic, ou the obliquity of, i, 12 Ecton hill, Derbyshire, mines of, ii. 318 Eel, natural history of, v, 484 ; de- scription of the electrical, 497 Et/i/>>t, remarkable mountain in, ii, 429; description of, iii, 14; on the climate of, iv, 77 ; magnificent re- mains of ruins iu, vi, 547 Egyptians, their knowledge in nstro- namy, i, 4 ; their traditions of the deluge, 247 ; their mode of reckon- ing, 203 ; m;«ps invented by, •*• their .-.kill in chemistry, vi, 3; art of writing among, 365 INDEX. / /'<• ur'iin, nr«'|>< Ttn-s of, v, i|iiii>n of the rivrr, i EldfH hole, Derbyshire, descrilx d, ii, 80 -ir fluid, nature and pr<>; of, iv. J7rd to, ii, IS; communication and \clocit \ of, iv, 27,r> ; atmospherical, 497; of thunder and lightning, 300; int-qui- librium, vi, 17 ; in motion, 26 Electrometer, construction of, vi, 41 Electrophone, description of, vi, 39 Elephant, fossil remains of, ii, !">.', l so, 192 ; natural history of, v, 05 ; me- thod of catching, 652 Elizabeth, ijtieeu, her encouragement of chemistry, vi, 10 Elk, fossil remains of, ii, 203 Embankments, on, iii, 375 Emen or cassowary, described, v, 616 •irllhiff,thc art of, vi, 419 Encaustic painting, the art of, vi, 425 Engraving, art of, vi, 440 Epicurus, doctrines of, i, 215 Epicyclet, defined, i, 15 Epsom mineral waters, iii, 178 Equator, definition of, i, 307, 309 Equilibrium, on electricity in, vi, 17 Equinoxes, on the motion of, 1, 16 Eratosthenes, astronomy of, i, 10 ; geo- graphy of, i, 293 Erckern, chemical works of, vi, 9 Eridanns, description of the, iii, 77 Erie, description of lake, iii, 248 Etesian wind, described, iv, 217 Etna, ^rneral description of; i, 403 ; eruptions of, 406 ; changes and present state of, 413 Eudiometers, description of, iv, 8, 12 Endows, opinions of, i, ]."> Euyiinean hills, drscri! •('ulph of, iii, 355 Flowers, classifications of, v, 8 Flora moss, in Kincardineshire, ii, 131 Flnid, on the electric, iv, 270; on tilt- attraction of, vi, 1«J Fluids, on the motion and resistance of, iii, 387 ; on their change to so- lids, iv, 53 ; made luminous, 6l INDEX. Fluxionf, the invention of, i, 175 /'«//, account of a remarkably dense, iv, 153 ; in Africa, 227 Forests, account of subterraneous, ii, 133, 146, 154, 1 >S Formations of rocks, classes of, i, 322 Fossil remains, general account of, i, 269; remarks on, ii. 144 , shells and zoophites, ib. 148 ; bones of animals, 151, 174; on artificial, 154; plants, description of, ib. ; origin of vege- table, 169 ; observations on fossil bones, 182; general history of, 189 ; ntensilsand ornaments, 271 , on the crystallization of, v, 3 Fountains, intermitting, iii, 80; tepid and boiling, 1O4 ; existence of the Ammonian, 142: inflammable*-*^ France, on the vines of, v, 77 Frankincense, description of, v, 176 Franklin, Dr. on water spouts, iv, 261 ; on electricity, 270 ; on thunder, and lightning, 301 ; his electrical kite, 305 Frog, natural history of the, v, 558 Frogs, experiments on, vi, 44 Frontignac, excellent wine of, iii, 243 Fucinus, description of the lake,iii,63 Fulgoria Lanteniaria^ description 'of, v. 383 Fulminating compositions, account of various, vi, 184 Furia, description of the, v, 378 Fyers, description of the fell of, iii, 2 1 7 Galileo^ astronomical discoveries of, i, 22 ; death and character of, 23 ; on the suction of the atmosphere, iv, 29 Galvanism, on the phenomena of, vi, 32 ; Davy's experiments on, 36 ; on the electricity of, 43 Gambia, description of the river, iii, 18 Ganges, description of the, iii, 10 Garnerin, his aerial voyage, vi, 77 > on the parachute of, 82 Garonne, description of the, iii, 27 Gasses, on the conversion of,iv, 57 Gas lights, on the application of, vi,88 Gassendi, on the system of, i, 216 Gaul, on the wines of ancient, v, 72 Gauts,or Indian appennines account of, ii, 426, 447 Gat/lenreuth cave described, ii, 201 Geler, chemical works of, vi, 6 VOL. VI. (,'i'iiatnr'm Abyssinia described, ii, 451 Geneva, earthquake felt at, ii, 44 ; lake of, iii, 234; tin.v and reflux in tin, 343 ; description of the city of, '^35 Genoa, descent of red snow at, iv, 172 /ji/,history of, i,296 ; principles of, 302 ; popular divisions of, 315 Geology, general system of, i, 230 j questions relative to, ib. 281 Geognosy, definition of, i, 230 Geometry, advantages of, i, 31. George, situation of lake, iii, -247 Georgia, discovery of southern, iv, 92 Georgiiim Stdns, elements of the, i, iGl ; observations on, 194 Germano, sudatories of St. iii, 242 Geyzers in Iceland, iii, 122, 127 Giant's causeway, country about the, i, 271 ; description of the, ii, 472 Gibraltar, description of the rock of, ii, 462 ; fossil bones i:i, ib. 467 Gigglcswivh well in Yorkshire describ- ed, iii, 86 ; observations on, 92 Gilding, the art of, vi, 3 15 Gilead, properties of the balm of, v, 1 7 8 Ginger plant described, v. 124 Glafiers in Swisserland described, ii, 410,415 Glamma cascade, account of, iii, 224 Glacis, the canton of, described, ii, 4 15 Glasgow, astronomical observations at, i, 132 ; extraordinary cold at, iv, 12 1 Glass, Mr. his journey to the Peak, i, 471 Glass, phenomenon of natural, i, 372 ; on the expansion of, iv, ,jl ; history of, vi, 153 ; properties of, 157 ; ma- nufacture of, IGl ; blowing of, 165 j used by the Romans, 323 ; art of painting on, vi, 412 Glaus, the art of painting on, vi. 412 Glasses, art of silvering looking, vi, 323 Gluxtonbnry waters, properties of, iii, 175 Globe, subterraneous phenomena o/ the i, 318 Globes, of fire-work how made, vi, 235 (ilummen in Norway, described, iii, .'.'.' Glory seeu on mount Hi nil, v, Gloucester, whispering gallery at,iv,546 Glow worm, description of the, v, 381 Gnat, natural history of, v, 417 diamond mine* in, ii, 989 b INDEX, (»'<>/-'7 , rendered jml.ihli-, \ i, I ; OB llu- art Ml'inakn.-r, it'. 7 ; < ••>ni|><>- Mtion of I'liliiiinnliim, it), 185 (ii>lit-fini-/i, natural hi*tor\ of, v, 639 . j.tion of toe, \, >I7 , mountains at (lie cape of, ii, 430; remarkable winds near, iv, ••llcnt wnU* at, \, ;.i iitsandx, format'ion ot'tlic, in, JM'. '•••.'i- in Yorkshire described, iii, I Golhard, Miiirular marble found on mount, ii, 384 ; drs* ribed,41 1, 418 Gottenb'irgk in Sweden, waterfall at, iii, •r/'crag in Cumberland described, iii, 262 GrtJiam, the inventions of, i, 33 Grampian hills, description of, iii, 270 (rrarite, ground-work of the globe, i, 236 ; formation of, 323 ; method of working, ii, 281 Grafinere. water, Westmorland, survey of, iii, 267 Gratshojiper, natural history of, v, 393 Gravitation, discovery of the law of, i, 168 Gravity, on the Kcplerian theory, i, 29 Greenland, Miss, her improvement of painting, vi, 429 Greeks, astronomy of the, i, 6; tradi- tion of the deluge among the, 247 ; geography of the, 296 Grenada, volcanoes in New, i, 485 Grotto at Fausilipo described, i, 510 ; of Antiparos, ii, 77 ; at Malta, 78 ; at Douse, in France, 82 ; near Besan- con, ib. ; del Cano, 103; of the Sibyls, iii, 62 ; of Neptune, 70 Hirer, course of the, iii, 31 in Spain described, iii, 31 tree, description of, v, 185 (,'tittrdian frigate, sufferings of the crew of,iv,99 Giianaxeto, account of the mines of, ii, 297 Gitettanl, M. on rivers, iii, 6 diiiinii irorm, account of the, v, 337 Clulfih MriMins, on, iii, 305 Gum ammoniac plant described, v, 208 ; Arabic description of, J<)l ; clastic, 295 j lac, account of, 399 Gun metal, composition of, vi, 285 (iiiii/nni:iJi-'; on bl.i.sti.i^ rocks b\, ii, , history of, \ i, Kis ; composi- tion of, 174 (inns, antiquity of, vi, 16Q Gi(tnnntr, extraordinary properties of 'the, v, 488 (ii/;>snm, on the formations of, ii, 209 / l:ii/n H/t, mount, description of, ii, 40.', K)H agitation of waters at the, ii, 58 Hail, causes of, iv, 1 4"» ; genera! nature of, isi; storms, violent ones, 182 Halifax, thunder storm at, i\, ,314 Haliri/, Dr. prediction of a comet, i, 143; his experiments on evapora- tion, iii, 4 ; on the variation of the magnetic needle, iv, 377 ; aurora bo- realis, ib. 394 ; on lights in the air, 400 Halos, on the phenomena of, iv, 517 ; instance of one, ib. 525 Haltios,or remarkable vapours, iii, 171 Hamilton, Sir W. on the eruptions of Vesuvius, i, 343 — 374 ; his visit to Etna, ib. 424 ; his account of the earthquake at Messina, ii, 59 Hannibal, his passage of the Alps, vi. 173 Harmattan, wind described, iv, Harrowgate spring, nature of, iii, 177 //a reforest, remarkable caves in, ii, 201 Harwich, cliffs described, ii, 150 Hastings, extraordinary phenomena at, iv,514 Hatfeld chase, submarine forest in, ii, 158 ; water spouts seen on, iv, 267 Hankadal springs in Iceland described, iii, 127 Haiiy, M. on crystallization, vi, 147 Heat of the atmosphere, on the, iv, 37 ; causes of, 46 ; sources and effects of, 50 ; comparative effects of, (> ". ; varia- tions of local, 67 ; in different coun- tries, 74 Heavens, construction of the, i, 61 Hebrides, volcanoes in the New, i, 466 Heckingham poor-house set on fire, iv, 340 ffeckla in Iceland, description of, i,447 Heights, table of, iii, 383 Helena, St. volcanoes in, i, 468 INDEX. 1 1 Henbane, description of the black,v,256 Herbarium, preparation and uses of it, v, S > 1 Helicon, description of, 408 Herculanentn, destruction of, i, 335; iliMo.ir\ of the ruins of, ii, 229 — 237 Htradta, remarkable cave at, ii, 76 Hercynian forest described, ii, 202 Herring, natural history of, v, 528 Herschel, Dr. his astronomical disco- veries, i,63 — 107 ; recapitulation of, 111 ; on the changes of the stars, 113; observations on the comet, 114; on the planet Venus, 178 ; op? lunar volcanoes, 183 Hertfordshire, storm in, iv, 184 Herelius, his astronomical discoveries, i, 30 Hiero, on the galley of, vi, 518 Hieroglyphic writing, on, vi, 342 Hindoos, their invocation of the Gau- ges, iii, 1 1 Hipparchus, his discoveries in astro- nomy, i, 12; geography indebted to, 14: the inventor of maps, 297 Holkham, whirlwind at, iv, 234 Holland, inundations in, iii, 285; on the embankments of, 379 Holywetl in Flintshire, described, iii, 175 Hooker, Mrs. mode of painting, vi, 430 Honey dew, cause of, iv, 153, note Horace, account of the villa of, iii, 72 Horizon, definition of the, i, 306 Horns of an enormous size, ii, 174, found in a tree, v, 315 Horse, natural history of the, v, 682 racing, antiquity of it, 685 Hoitus siccns, advantages of an, v,321 Howard, Mr. on meteoric stones, iv, 469 Hnbtrr, M. his observation on bees, v,4 Hudson's bay, remarkable well in, iii, 1 4.> , description of, iv, 39 ; effects of cold in, 1 14; river described, iii, 42 Human bodies, preservation of, iii, 121, 142 Hnmber, description of the, iii, 36 lluinliuldt, on tin- l» itilitness of stare, i, 190 ; on the mines of South Ame- rica, ii, 297 Hum mucks, account of basaltic, i,293 Hnmminy bird, description of, \ Hunter, Dr. on fossil bones, ii, 1 82 ; on the climate of Jamaica, iii, 107 Huntingdonshire, storm in, iv, 244 Huntsman's steel, discovery of, vi, 293 Huron, description of the lake, iii, .' i ; an- tiquity of letters among the, vi, 37 " p!;ait described, v, 287 Indus, course of the river, iii, lo Industrie, ruins of the ancient city of, ii, 9 lnrfi Jnk.t, various kinds of, vi, 385 f, clat-Mtic.iiion of, v, 342, S79 Intestinal worms described, v, 376 Inundation of Ilir Thaim s li, 147 Innndatians, general account of, iii, 283 Ionian school, doctrines of the, i, 7 Ipecacuanha plant described, v, 200 Ireland, ou the bogs of, ii, 184; fossils in, 174; on the fossil elk of, 203; copper mine in, 277; mineralogy of, 326; mountains in, 446; on the lakes in, iii, 2*6, 246 ; on the tem- perance of, iv. Iris, theory of the, iv, 506; of the lunar and solar, 528 /row, in lavas, i, 512 ; superiority of Swedish, ii, 277 ; in North America, 315; in Ireland, 328 ; filings, mag- netic, iv. 370 ; on the Siberian, 484 Iron tree, formation of the, vi, 327 Iron works, in North America, ii, 316; at Colebrook Dale, 322 Irridescent arches described, iv, 526 Ischia, description of the island, i, 348 Isinglass, preparation of, v, 537 It lands, thrown up suddenly, i, 495 ; formed of bones, ii, 195 ; formation of coral, iii, 291 ; warmer than con- tinents, iv, 39; of ice, in the sou- thern hemisphere, 90. Isola Bella, description of, iii, 239 I sola Madre, account of, iii, 240 Isthmus, between Calais and Dover, iii, 301 Italy, on the temperature of, iv, 49; winds prevalent in, 191 Jalap bindweed, description of, v, 190; medicinal qualities of, 191 Jamaica, earthquake at, ii, 6 ; moun- tains of, 433 ; the temperature of, iii, 107 ; meteor seen at, iv, 457 ; pepper tree of, v, 125; logwood in, v, 289 Japan, on the volcanoes in, i, 464 ; mi- neral productions of, ii, 2S7 ; moun- tains in, 427 ; description of, iii, 305 ; paper tree of, v, 282 Jam, insalubrity of, iv, R4 ; poisonous plants in, v, 2*79 Jin a, St. de Port, description of, ii, 420 Jerusalem, ruins and present appear- ance of, vi, 519 Jesuits bark described, v, 146 Jezzo, on the straifs of, iii, 305 Jocox? shrike, description of, v, .r>88 Johns, St. near Keswick, described, iii, 2S4 Jorn/lo, the volcano of, i, -t*'» , elements of the planet, i, I >s ; view of the heavens from, 193 ; eclipses of the satellites of, 208 Jinn, on the mountains of, ii, 416 Kadxi, or paper tree described, v, 212 hatca, volcanoes in, i, 465 ; hot .springs in, iii, l6l Kentucky, state of the province, iii, 40 Kepler, on the discoveries of, i, 25 , or scarlel dying insect, v, 398 Kfi-i/n Bryn in Wales, described, ii, 444 Kh inn seen wind, account of, iv, 222 Kian Ku, in China, account of, iii, 12- Kilkenny in Ireland, cavern at, ii, MI Kincardine, on the peat mosses oi, Kiiir/, Mr. his theory of the deluge, i, 261 Kingston, in Jamaica, temperature of, iii, 111; variations of heat at, iv, 75 Kircher, his visit to Etna, ii, 3 Kirhag river, cataract on, iii, 224 Kist vaens, account of, vi, 50."> Kite, invention of the electrical, iv, 3 05 Knight, Dr. his invention of magnets, iv, 388 Konigsberg in Norway, account of, ii, 284 Krabla in Iceland described, i, 4 :>~> Labyrinth of Crete, ii, 77 ; remarkable one, vi, 477 Ladoga lak« described, iii, 232 7,«r///-bird, natural history of, v, 400 Lago Maggiore, account of the, iii, 233 l.iii/nna lake, in Italy, iii, 238 Lakes, description of picturesque, iii, 50 ; Vadimon, 55 ; the Lucrine, 56 j Avernus, 61 ; Fucinus, 63; periodi- cal, 80; Zirknizer, 97 ; bituminous at Trinidad, 150 ; general survey of, 231; in Great Britain, 243; parti- cular, 253, on the salt, 313 l.nii'i.i of Thibet, residence of, ii, 42 Lamas in South America, description of, v, 267 Lancashire, water spout in, iv, 265 iMncasler, winds at, iv, 193 Land and sea breezes, iv, 225 jMiids, on the formation of new, iii, 2*93 Language, ou the notation of, vi, 359 INDEX. lantern, fly, account of the, vf S81 Lapis nnnimouaris, description of the, ii, 459 Laplace, astronomical observations of, i, 141 Upland, remarkable lake in, iii, 171 Lark, natural history of the, v, 632 Latham, Mr. on the earthquake at Lis- hoii, ii, 35 ; on an atmospherical re- fraction, iv, 514 latitudes and longitudes, invention of, i, 297 Laurel mountains, in North America, ii, 432 La uro cerasus, poisonous quality of the, v, 246 Lara, extraordinary flood of, i, 369; observations on, 373 ; a river of, 4 16; iron in, 5 1 2 ; various kinds of,52 1 Lavoisier, memoir of, i, 5, note Latcdoor waterfall, described, iii, 261 Lawrence, description of the river St. iii, 41 Lai/well spring, account of, iii, 85 Lead, found in Ireland, ii, 323 Leadenhall-street, Roman pavement found in, ii, 266 Lead hills in Scotland, ii, 323 Lead mines in Derbyshire, phsenome- non in, ii, 46; in Louisiana, account of it, 3 14 Lead tree, how to make the, vi, 327 Leather, description of mountain,ii,39 1 Lrtand, his observation on Wales,ii, 127 Lrtnnos, labyrinth of, vi, 477 Lestwithiel church, injured by light- ning, iv, 324 Letters found in a tree, v, 314 • origin of, vi, 351 Leitck, account of the baths of, iii, 165 Leyden, agitation of waters at, ii, 58 Libanus" mount, description of, ii, 425 Lichens, observations on, v, 35 Lidford waterfall, account of, iii, 222 Liyantfiin river, source of the, iii, 66 Light, on zodiacal, i, 93 ; of the stars, 137 ; on the velocity of, 189 Light-houses, account of, vi, 528 Lightning, on the cause and effects of, ii, 1") ; used in blasting rocks, S81 ; on the electricity of, iv, 300 ; drawn from the clouds, 306 ; how to secure buildings from, 308 ; strange effects «f, 312— 361 Lights in the air, iv, 40O ; remarkable red, 416; various metcorous, 4*7; uses of gas, vi, 88 Lima, destruction of the city of, ii, 7, 8 Lime stone, nature of, ii, 279 Lime water, uses of, iii, 189 Lincolnshire, fossil remains found in, ii, 166; Roman antiquities in, 217 ; water spout in, iv, 269 Linen, ink for marking, vi, 396 LinnfEus, his system of plants, v, 17; brSclassification of animals, 327 Lion's hill, at the Cape of Good Hope, ii, 430 Lipari islands, volcanoes in, i, 435; water spout seen near, iv, 266 Liquorice plant described, v, 142 Lisbon, account of the earthquake at, ii, 31 Literature, arts connected with, vi, 328 Lithography, or stone engraving, art of, ii, 444 Loadstone, observations on the, i, 228 Lobster, natural history of the, v, 480 Loch Leven, account of, iii, 245 Lomond, description of, iii, 268 Ness, description of, iii, 218, 272 Tay, agitation of, iii, 287 Locust, natural history of the, v, 384 Logarithms, invention of, i, 30 Loggan stones, account of, vi, 505 Logwood, use* of, v, 289 Loire, course of the river, iii, 27 London, stars visible at, i, 203 ; mean temperature at, iv, 79 Longevity, instances of, iii, 271 Longitude, on the invention of, i, 297 ; on the difference of, 308 Lough Lene in Ireland described, iii,21 Lough Neagh, the scenery of, iii, 246, 274 Louisiana, lead mines in, ii, 314, 317 Lucia, St. volcanic remains at, i, 491 Lucretius on Etna, i, 405 ; on the Nile, iii, 16; on hot springs, 140; on mag- netism, iv, 32 1 Lucrine lake described, iii, 56 Ludgevan, Cornwall, storm at, iv, 321 Lnlty, Raymond, his doctrine, vi, 9 Lumen Boreale, observations on the, iv, 414 Luminous arches, account of, iv, 421 ; exhalations, iv, 501 14 INDEX. Lunar mountains described, i, l«Jl ; rainbow n. P. i!. <.-lm. . n , — — solar, period, i, 3 Lunanli, Ins .\ HI! woymgt, \ i, 74 Luxor, in 1'irvpt, ruins of, \ i, ;;»'j / ,n, description of, ii, Lyons, Israel, ehar.it ter of, iv, 104 •:r, •(( s< nption of iiie, v, 595 . on the oil of, iv, 128 Maikurel, natural history of the, v, 506; on the shining of, vi, 106 Mackenzie, his journey to Iceland, 1,447 Madar/ascar, gold in, ii, 292 .Madder, on the uses of, v, 991 Mudtira, earthquake at, ii, 4-' ; on the wines of, v, 75 Madrid, earthquake at, ii, 38 i; in Carniola, ii, 279 rock, in Ireland, i. hemispheres, what, iv, 29 Maynctical experiments, iv, 387 Mai/ni'tir needle, variation of, iv, 377 Mai/netitm, principles of, iv, 362; the- ory of, vi, ii Mai/nets, construction of artificial, iv, 388,391 Malabar, winds on the coast of, iv, 242 Malaria, on the wines of, v, 77 Maler lake, in Sweden, iii, 233 Malta, grotto in the isle of, ii, 78 Maize or Indian corn, uses of, v, 58 Mam Tor, in Deri;;, shire, ii, 83 Mammoth, discovery of the bones of tin', ii, 178, 198; description of the, v, 569 Manchineel tree, described, v, 265 Miinuti, account of the, v, 656 Manetho, the history of, vi, 367 Mamjerton, in Ireland, description of the valley of, i, 291 ; height of the mount of, ii, 446 Manioc, or cassava tree, v, 54 Manna tree, description of, V, 132 Manuscripts found at Herculaneum, ii, 246; description of a remarkable, vi, 287 Maple sugar, how made, v, 84 Maps, the inventor of, i, 297 Marble, how smoothed, ii, 281 ; in Ire- land, .J'2l); various kinds of, 383; elastic, 384 Marble cascade, account of, iii, 219 Warranters, or the inhabitants of the Alps, ii, 413 Marroon*, construction of, \i, 226 Mars, '. vrvatioiis on the [ --Ian. i, • •incuts of, 157 ; pe- nfii.inlii's in, 193 MarsHtii, Mr. lii>ar i ..... it of'ifo«r,iv,153 Martin Met r, Cheshire, antiqui: ii, Kit . //.», iron in, ii,.; !."» .MtititHH. 1 J«'rh\*li lie, springs at, iii,l?(> Ma iritiiif, inundation in the isle of, iii, 283 Muire, Mr. on diamonds, vi, 301 Mai/aratflio lake described, iii, Mai/ola, description of the valley of, t/ fly, account of the, v, 414 iiti nt of the earth, i, 1 1 s and weights, table of ancient, vi, 600 Mechanical sciences, history of, vi, 465, 535 '•••ell in Northamptonshire, cold- ness of. iii, 143 preparation of, 30 ; on fulminating, vi, 186; divisions of, 317 Meridian, definition of a, i, 307 Messina, earthquake at, ii, 59; optical deception at, iv, 509 Metallic trees, how made, vi, 326 Metallurgy, general principles of, vi, 246 Metals, art of working, ii, 260 ; on the expansion of, iv, 51 ; division of, vi, 285 Meteoric stones, history of, iv, 568, 475 Meteors, extraordinary, iv, 427 ; one seen all over England, 432 ; of a flaming sword, 43 1 ; fiery ones, 442 j accompanied with balls, 457 INDEX. 15 Melon, astronomical observations of, i, 2»7 Mericant, calendar of the, i, 35 ; hiero. L.rl \phic8 of, vi, 346 Mexico, volcanoes in, i, 479 ; mines of, ii, ->93 ; lake of, iii, 314 Methom mineral springs, iii, 167 Michael, St. phenomenon at the isle of, i, 503; on the Caldeira of, iii, 1 14 Michegon, description of the lake, iii, 249 Mifhell, Mr. on the fixed stars, i, 185 M'ddietuii, Sir Hugh, account of, iii, 37 Migration of birds, on the, v, 640 Mi'ky way, observations on, i, 191 Milo, or Melos, situation of, ii, 77 Mimosa nilotica, properties of, v, 294 Mineral kingdom, on the, v, 3 Mineralogy, remarks on, i, 507 ; s\ s- tem of, ii, 263 Minerals, various species of, ii, 26'J Mineral waters, general view of, iii, 161 ; domestic, 171; on analysing,; 178 Mines, general viewof.ii, 274 ; of Great Britain, 279,318; of Europe, 283 : in Asia, 287; Africa, 292 ; of Ame- rica, ib. ; Mexico, 297 ; the United States, 313 ; in Ireland, 326 ; quick- silver, 329 ; account of coal, 337 ; description of the salt, 366 Mining, observations on, ii, 273 ; on terms in, '27 6; process of, 280 Mirages, or optical delusions, iv, 505 Mirrors, on metallic, vi, 291 ; on burn- ing, 458 Misery, description of mount, ii, 433 Missel bird, account of the, v, 620 Mississipi river described, iii, 39 Mitt, incidental arches in a, iv, 526 Mistral, a wind in the Alps, iv, 234 Mitts, causes of, iv, 14-2 Mockiny bird described, v, 624 Modena, ancient remains of, iii, 296 Motris, on the lake, vi, 458 Mofete,& pernicious vapour, i, 397 ; ef- lW-ts of the, ib. 402 Moisture, on the force of, iii, 410 Molecules of ice, on the, ii, 282 Molluscous worms, described, v, 356 Monkey, of the preacher, v, 649 Monsount,of the Indian ocean, iv, 186 ; causes of, 201 ; account of, 2 1 1 Montayna Nuovo, in the Lucrine lake, Montyolficr, Messrs, invent the bal- loon, vi, 66 Montserrat, volcanic, mountains of, i, 492; monastery of, vi, r»()2 Monumental antiquities, vi, 505 Moon, observations on the, i, 13 ; libra- tion of, 14; ele;nents of, 162- ; volca- noes in, 183; mount-tins of, 194; rivers in, 190; eclipses of, 2OO ; in fluence oX»he tides, iii, 33O Moon, mountains of the, in Africa, ii, 429 Moose deer, extinction of the, ii, 177 Morai, or cemetry and temtile of the Australasian Islands, vi, 491 Morisqne bath in Portugal, ii, 422 Morocco, earthquake in, ii, 422 ; seal of the emperor of, vi, 354 Mom/r account of the creation, i, 244; of the deluge, 246 Mosambiqne channel, monsoons in. tv. 213 Mosetlafe beck, Westmorlajul, iii 3 O Moses, Hie inventor of letters, vi, 303 Mosses, on bog aud peat, ii, 118 u Scotland, 121 ; oi Kincardine, 129; irruption of the Solvay, 139 ; pre- servative power of, 142 Mother of penrl shell described, v, 369 Moths, description of, v, 408 Motion, on circular, i, 1 i of the earth, on the, iv, Motions of the planets, i, 208 Mountains, on the lunar, i, 194 ; for- mation of, i, 2 10; on primitive, ii, 395 ; on the sulphur, 458 ; descrip- tion of the chief, 402 — 440 ; fre- quency of rains on, iv, 149 Mules, the sagacity of, ii, 438 Mnlgrave, voyage of Lord, iv, 100 Multivalee shells, account of, v, 375 Muriatic acid, efficacy of, iv, 24 Music, ancient manuscript on, ii, 245 Musqnito, description of the, v, 417 Mylassa, the remains of, vi, 505 Myrrh, account of, v, 163 Myrtle, the candle-berry, v, 300 Mysore, high lands in the, iv, 220 Sanies, derived from situations, i, 3 IS \ankin, porcelain tower of, vi, 500 \tf/>/Vr, his invention of logarithms, i, 30 Naples, alarming state of, i, 359 ; earth- quakes at, 377 ; meteors at, iv,4l6 INDEX. Nature, wiie provision of, v, 31 :l\u, description of the, v, 365 N*val architecture, Instorv of, v Nebula; observations on various, i, 63, 108 Needle, on the variation of the, iv, 337 ; observation* on the magnetic, 387 Needles e\c, Derbyshire, ii Neyro, ajiecdote of a, ii, 3os Nephile, inoiiut, described, ii, 4"7 •if, description of the grotto of, iii, 70 Neptunian theory of the earth, i, 236 Ness, a river in Flanders, iii, 296 Nenfchatel, earthquake at, ii, 43 ; lake of, iii, 236 Nero, course of the river, iii, 22 Newcastle, description of, ii, 338 New Forge in Iceland, storm at, iv,314 New Grenada, volcanoes at, i, 4s~> New Hebrides, volcanoes at i, 466 New river, account of the, iii, 37 New York, earthquake at, ii, 45 Neu-tnii, Sir Isaac, account of, i, 169, philosophy of, 921 Niagara, the falls of described, iii, Jl"> Nieper, account of the, iii, -21 Niger, source of the river, iii, 1 8 Nightingale, description of the, v, 633 Nightshade, varieties of the, v, 250 ; remarkable effects of, 2.1 Nile, source of the, iii, 13 ; description of, 15 ; inundations of the, 16; cata- racts of the, 213 A/;«//«« plant described, v, 294 Nitric acid, solutions in, iii, 197 Nitrous gas, experiments on, iv, 8 Noah, history of, i, 246 ; vi, 513 Nodes, definition of, i, 208 Norfolk, antiquities in, ii, 24 ; fiery whirlwind in, iv, 254 Northamptonshire, earthquake in, ii, 22; sea-shells found in, 15O; storms in, iv, 252; effects of lightning in, 317 Northern hemisphere, congelation in, iv,37 North polar regions, rold of the, iv, 100, 106, 1 1 1 Nitrtfi river in America, deacribed,iii, 42 Nortk west passage, conjecture on, iii, SOS Northwich in Cheshire, salt works at, ii, 372 Norway, silver mines in, ii, 284 ; spring* in, iii, 222 \iin( Xcmhia, description of, iii, 303 .\nti/alls, experiment with, iii, 1'Mi Nutmeg tret; account of the, v, I J? Nut, account of the votnic, \, Oaks, .submarine, ii, !' O/ilitjnt: sphere described, i, .'>!<> Ocean, varieties of the, i, 3 1<> ; div . of the, iii, 289 ; advances and MOJIS of the, ii'JI ; temperature « iv, 33 Ochreout earths, remark on, i, Oh in, fossil bones at (lie, ii, l.Vj, I«»S; description of tiie, iii, -ID Oil, its effects on the waves, iii, .359 ; of thecajeput tree, v, yn<) O lif 11 hole, Somersetshire, described, ii, 90 Olive tree, account of the, v, 67 Olives, how preserved, ib. 68 Olympus, description of mount, ii, 406; of the Myssians, 423 Omiiie, a remarkable mountain in Ja- pan, ii, 427 Onri/ii lake, described, iii, - Ontario, account of the lake of, iii, 248 ial, mines of, ii, 287 Opium plant described, v, 215 Opoculpasnm, on the gum, v, 166 Oporto, earthquake at, ii, ~>7 Optical appearances, singular, iv, 509 Orantj Outanu', description of, v, G47 Ortynn river in America, iii, 39 Orellana, enterprise of, iii, I > Orbits of the planets, on the, i, 207 Ores, met. us of, on detecting, ii, Optics, Newton on, i, 174 Orickalcum, of the ancients, vi, 27tt Oriuii, on the constellation, i. 7 I, !»!> Orizaba in Mexico, volcano of, i. Orleans, account of the isle of, iii, 41 Orbit, diameter of the earth's, i, 180 Or Mouln, on gilding in, vi, 315 Oi-onouko, description of the, iii, 44 Orthoceratites, a putrefaction, ii, |.>1 Oscillation, of the pendulum, on the, i, 154 Osta mount, described, ii, 407. fMrit-h, natural history of the, v, 609» method of hunting the, 61 1 , American, 015 INDEX. 17 Ovcego, course of the river, iii, 248 Ottaiano, ruin of the town of, i, 365 Ovens, account of volcanic, i, 481 OJT, natural history of the, v, 676 Oxfordshire, agitation of witters in, ii, 53 Oi -net/ isle in Kent, formation of the, iii, 293 Ox's eye indicative of a storm, ii, 10 Oxygen gas, experiments on, iv, 0; emitted liy plants, 'J I ().nnnnriaticacid, composition of, iv,24 Oyster shells, remarkable bedsof, ii, 1 49 Pacific ocean, observations on the, iii, 289 ; temperature of the, iv, 38 Paderboru, of the springs of, iii, 83 Padua, meteor seen at, iv, 417 Painting, history of the art of, vi, 410; on glass, 412; encaustic, 425; of paper hangings, 430 Pallas, on the planet, i, 193 Pallas, professor, account of, ii, 457 Palm oil tree descrited, v, 1 19 — wine, how prepared, v, 1 19 Palma, account of the isle of, i, 409 Palmyra, situation of, iv, 8 1 Pangeeus, description of mount, ii, 402 Paper, art of making, vi, 328 of the ancients, vi, 386 — : — nautilus, description of, v, 365 tree of Japan described, v, 282 Papyri, discovery of ancient, ii, 246 Parallax of the tixed stars, i, 58 Parallels, on celestial, i, 310 Paraselenites, account of, vi, 504 Parhelia, observations on, i v, 506 ; seen at Danl/ic, 521; at Sudbury, 523; at Lyndon, 524 Paris, subterranean caves at, ii, 1 13 ; on ,the petrifactions of, 205 Parnassus, account of mount, ii, 408 Parrot, natural history of the, v, 591 Parthenium, of the promontory of, ii,452 Pari/s mountain, Anglesey, described, ii, 318 Pasaic river, North America, course of, iii, 225 Pasto, in South America, described, i, 488 Pataxet, iron works on the, ii, 3l6 1'arements, discovery of Roman, ii,220, 266 Peak of Teneriffe, journey to, i, 47 1 of Derbyshire described, ii, 83 Peaks, of mountains on the, ii, 411 VOL. VI. Pearl muscle, description of, v, 369 ; fisheries, account of the, 370 ; nau- tilus, v, 366 Prat mosses, account of, ii, 129 Pebbles, origin of, ii, 3K6 PeclJiam, meteor seen at, iv, 442 Peerless poo!, phenomenon in, ii, 51 Peijttis lake, description of, iii, 232 Pclion, description of mount, ii, 407 Pembrokeshire, exhalations in, iv, 502 Pendulum, on the invention of the, i, 30 ; shortened at the equator, 154 Pendulums, sympathy of two, iv, 547 Penens, description of the stream of, ii, 407 Penman-mawr in Wales, height of, ii, 443 Pen-park hole, in Gloucestershire, de- scribed, ii, 91 Peninsula defined, i, 31.5 Pennsylvania, earthquake in, ii, 45 Pepper plant, description of, v, 131; tree of Jamaica, v, 125 Perch, natural history of the, v, 513 Perihelion of the comet, on the, i, 138 ; of the planets, 148 Peritfd, account of the, i, 314 Persia, on the deserts of, ii, 482 Persians, on the learning of the, vi, 377 Perthshire, on the mosses of, ii, 129 Perugia, description of the lake of, iii, 241 Peruvian bark, account of the, v, 140 lantern fly described, v, 383 Peru, no rains in, iv, 15 1 Petersburgh, situation of, iii, 22 Petrifactions, remarks on, ii, 144; on vegetable, 146; shells and zoo- phytes, 148; singular species of, 150; bones, 151 ; in the suburbs of Paris, 205 Petrifying springs in Ireland, iii, 276 Pewter, composition of, vi, 299 Peifrerius, his system of preadamites, i, 250 Pharsalia, on the plains of, ii, 407 JJhenicians, knowledge of letters among the, vi, 368 Philodemus, account of, ii, 255 Phi Pl>s, Capt. voyage of, iv, 101 Phlegraan field described, i, 513 Phlogisticateil alkali, on the, iii, HH Phosphorescent stones, account of, ii,385 Phosphorus applied to the abstraction 1 INDKX. of oxygrn, iv, 1:2; of Kuiirk. I, • i, i07 ; calori/ed, I K); . • t.i'jl.-, i!>. Phi/ait- hislor/ of \\stemntir, i, 214 ri ••:!, i, i :fy to, ii, 435; cold on Ihr summit of, i\ Picture writing, historic account of, vi, 342 Pictures, discovery pf ancient, ii, 231, 244 fit/eon, description of the, v, f>2 ") Pil.itr, mount, in Switzerland, ii, 417 Pimento tree, deseript ion of, v, 1 .- • Pitch lake, a remarkable, iii, 1 •'>() pine, description of the, v, 173 Planetary nebula;, on the, i, 97 P lands, conjectures on the, i, 36 ; ele- ments of the, 146; inequalities of the, 140; telescopic, l6l ; general observations on the, 192; on the re- lations of the, 207 Plantain tree, description of the, v, 52 Plants, oxygen ^:t> emitted from, iv, 22; spontaneous movement of, v, 2 ; classification of, 5 ; natural history of, 19 ; nutritive, 42 ; medicinal, 34; useful, 282 ; metallic, vi, 326 Plata, La, of the mines of, ii, 292 ; course of the river, iii, 48 Plating, the art of, vi, 307 Pliny the elder, death of, i, 339 account of the remora, v, 508 Plumbago, properties of, ii, 324 Plutonic theory of the earth, i, 232 Plymouth, waters agitated at, ii, 54 Plynlimmon, in Wales, described, ii,444 Po, description of the river, iii, 32, 77 Poisons, account of vegetable, v, 221 Poland, salt mines in, ii, 274, 367 Polar effusions, the tides attributed to, iii, 335 Polarity of magnets, on the, iv, 364 J ole, voyages towards the north, iv, 100, 1 1 1 Pulyylitt bible, the first, vi, 404; his- tory of the Knglisb, 407 Polypes, description of, v, 352 J'omjieii, (icstriH lion of, i, 335; disco- \i r\ . Hie ruins of, ii, .218 .Tout .\i nf, at Paris, described, iii, 30 1 (j)tte Liifio, ruins of, iii, 70 itolf, Derbyshire, described, ii, 83 Porphyry, singular species of, i, 4b8 t'ortiii, Mihl< Train-on:, town at, i /'<»•/ litiii.-t!, Jain I, ii, (> t'ortti) itatiooo i r.> at,ii, 17 !'• itnyui, minerals of, . . • niii*, hi.s measurement of the :h, i, 1 1 I'ni iHftttt, oumpoMtion of, vi, 289 Potusi, account of lli. nun. s (.:', u, '(> I , course of the river, iii, l;> .t, composition of fulminating, \i, 18-1 PoH-rrscourt, in Ireland, cascade at iii, Preadnmites, system of tip Prefers, on the baths of, iii, Mi I Presters, or waterspouts, account of, iv, 2.56 Price, an excellent painter on glass, vi, 414 Priestley, Dr., discoveries of, iv, 6 Prime numbers, on finding, i, 2o.i Primitive formations of rocks, i, 322 Printing, history of, vi, 39S ; cVi.M.l from China, 399; progress of in England, 405 Protnontories, remarkable, i, 273 Psalter of Mentz, account of, vi, 401 Prussian blue, origin of, iii, 194 Ptolemy Pkiladelphus, institutions of, i,9 . the astronomer, account of, i, 14,302 Pudding stone described, ii, 30G Pnmice, various kinds of, i, /-!" stones, remarkable, i, 4(»~.»; shoal of, iv, 165 Putala, in Thibet, account of, ii? Pyramidal appearance of the heavci:*, 'iv, 522 Pyrenees, description of the, ii, 419 Pyrites, observations on, i, Pi/rmont waters, (juality of the, iii, 167 Pi/rotcchnii, principles of, vi, 21 i P',/!f«t:-;oras, doctrines of, i, 7 Qninli-ttnts, on the application of tele- scopes to, i, 33 Quadrupeds, on unknown, ii, IT New Holland, ^Oo; general tit tiou of, v, 647 Qiuigga, natural history of thrr \ , Q.\nu ries, subterraneous, at Paris, ii, 1 1 > Quicksilver used 1.1 extracting .lilicr, ii, 298 ; description of the min 329 i affecting scene iu the, INDEX. 19 its use in extracting gold and silver, vi, 3 1C; experiments on, 319; ap- plied to mirror i(/t antiquity of horse, v, 085 AW;/, itst fi. .* on rocks, i,2,'>d; general observations on, iii, 3; experiments on, iv, 20; causes of, 143; at the equator, 148; on mountains, J49; unusual fall of, 150; violent at Den- bigh, 155; at Rippondcn, 150; salt, ! ">r ; observations on the snine, 158; volcanic, l6l ; of anew kind, 162; of fishes, 166 Rainbow, an inverted, vi, 524 ; solar and lunar, 528 ; lunar one in Derby- shire, 529 Ttaleit/h on the height of mountains, i, 260 Ramtdfte, optical deception at, iv, 516 Rarefaction, observations on, iv, 203 Rattlesnake, natural history of the, v, 566; on the rattle of, 569; on the fascinating power of, 570 ; experi- ments on, 57 1 Rat/, his botanical system, v, 10; witty remark of, v, 358 Reading, in Berkshire, phenomenon at, ii, 53 ; bed of o\ ster shells at, 1 49 Re-agents, observations on, iii, 188 Realt mount, glory seen on, iv, 530 Redbreast, natural history of the, v, 636 Red lights in the air, iv, 416 Red snow at Genoa, iv, 172; on the Alps, 173 Refractions, atmospherical and double, iv, 514, 516 Rryuliis, fate of the army of, v, 576 Jieicheuait island, description of, iii, 234 Rcmora, description of the, v, 508; origin of the fable concerning, 511 RejMMMM%otl the power of, iv, 56; on electric, vi, 24 Resitia, in Italy, temarkable well at, ii, 229 Returning stroke in eletricity, iv, 336 Revolution, duration of a sidereal, i, 147 Ret/hum springs in Iceland, account of, iii, I i'J Rhea, or American ostrich, described, v, 615 Rhine, gold in the sand of the, ii, 286; course of the river, iii, 23 Rhodes destroye.l by an earthquake, ii,'2 Rhodope, description of mo-Mr, ii, 408 Rhone, account of the river, iii, ^~>; |v;ulS'.ir nind on the, iv, 234 Rhiilnrb, drscrutiio'i of, v, 19(5; two sorts of, IQgypurgative (utilities of, H.';> / ffihar in Hungary, baths of, iii, 165 Jtice, on the culture o»', Rir/t:nan, professor, death of, iv, 353, 357 Ridis, spontaneous combustion of, iv, 502 Rille, in France, disappearance of the, iii, 7 Ring ouzel, description of the, v, 624 Rings, cause of ruiry, v, 316 Riobambo, South America, destroyed, i, 487 Rio Janeiro, commerce of, ii, 304 Rio de la Plata, description of, iii, 48 Rion, lieutenant, sufferings of, iv, 99 Rippendon, violent rain, at, iv, 156 Rivers, on the course of, i, 317 ; on the origin of, iii, 5; disappearance of, 6, description of principal, 10 — 50 Roads, construction of Roman, ii, 137 Rochford, phenomenon at, ii, 52 Rockets, construction of, vi, 212 Rocks, method of blasting, ii, 275 Rocks, description of, i, 319; struc- ture of, 320; formation of, 322; on volcanic, 508 ; on the vegetable pro- ductions of, v, 32 Rock-bridge in Virginia, described, ii, 439 Rock-salt in Cheshire, works of, ii, 369 Rochia, Joseph, remarkable history of, iv, 177 Roger Rain's house, Derbyshire, ii, 85 Roggewein, voyage of, iv, 89 Roman antiquities in Britain, ii, 165, 217,221,227; at Hercuianeuni, -.^7 Roi;al Society, account oftlic, i. — canal in France; iii. '27 Rudder, on the force of tin-, is:, 36-1 Ruins of Hcrciilanenm, ii, v>-29 ofthc Parthcninin, ii, ! Balaclava, Rnm, properties of, v, 83 Rum ford, count, on preparing coffee, v/108 llnperCs drops, nature of, vi, 166 Sabrina, account of the isle of, i, 506 Sadler, his terial voyage, vi, 75 Sayo-tree, description of, v, 59 Sahara, account of the desert of, ii, 483 Saint Pierre, his theory of the tides, iii, 329 Sai ammoniac in volcanoes, i, 526 Salnmander, account of the, v, 556 Saline \\ tter>, observations on, iii, 183- Salle in Barbary, earthquake at, ii, 41 Salmon, natural history of the, v, 519} fishery, account of the, 520 Salt mint's in Poland, ii, -274; descrip- tion of, 367; works in Cheshire, 369 Salt rain, storms of, iv, 157; observa- tions on, ).;8 Salts, on crystallizing, vi, 143 Samp ford Courtney, Devonshire, storm at, ii', .117 SawjWwind, account of the, iv, CS2 Sund, whirlwind of, iv, 254 Sandal, description of au ancient, ii, 144 Santorini, earthquake at, i, 499 Saj> tXndrc river, disappearance of the, iii, 8 Saros, the ancient period of, i, 3 'tea, observations on, i, 161 ; of Jupiter, 166; of Saturn, 167; of -MIS, 1G8 Tonomical elements of, i, virellitcs of, 167 ; distance of, ]'_•> \ ; irs of, 193; o a the ring of, iv,SS3 Sauciuons, construction of, vi, 226 Saunderson, Dr. account of, iv, 546 Saussure, livgroiiietrical obse r\ ations of, i \ . ,caroy, on the inh:i!)itnnts of, ii, 412; mountaneous nature of, 414 ••ilrr, -diirc:- , .f tl.e, iii, -,n Stat/nnony, properties of, v, 188 iaruroiifjn, on thr wntrrs of, ni, 177 Setirdian inountniiis, account of, n, t')J i t I'INC HIM •••!, .ievnlted, v, 398 , bridge of, iii, vi I ; cata- ract of, -J,M 1 Sthecle, foul air of, iv, 6; the eudi- ometer of, 10 Schwartz, the inventor of gunpowder, vi, 168 Scilli/ islands, changrs in the, ii, current at, iii, Scio, vineyards in the isle of, v, Scoolkill in America, source of, iii, i ; Scotland, mosses in, ii, 1C21 ; minera- logy of, 323; mountains of, 445; remarkable storms in, iv, 204, 330 Sea, islands thrown up from the, i, changes of the, ii, 145; on gaining land from the, iii, 374; advances and recessions of, iii, 291; saltness of, 307 ; less heated than land, iv, 44 ; mean heat of, 74 ; antient extent of, \, J7; luminous appearances of, vi, 117, 127 Seas, temperature of small, iv, 38 Sca-anenome, description of the, v,363 Sea-breezes, observations on, iv, 1 :- • , Sea-jnnna, account of, v, 374 Sea-water, mode of sweetening, iii, 368 Seasons, on the change of, iv, 48 Seine, account of the, iii, 30 Selenitic origin of nu-leoric stones, iv, I-', Seltzer train; account of, iii, 168 Senegal river (ie?.cril>« . •., ni, I7j exces- sive heat in, iv, 75 Senna tree, account of the, v, 137 Serpents in fireworks, coiibtructiou of, vi, /, conr.se of the riv« r, iii, 34 S/utdou-s, names t;'.ke n from, i, 313 .'-. ' 'iiiiHtn, cataract on the, iii, _','4 Shark, natural history of the, v, 538 Shark's teeth or glossopetne described, ii, 14«J Sheep, natural history of, v, twj/ ; va- rieties of, t>7 _' Shitriii-ix, rcmi'.rkable. •well at, iv, 73 Shell, mothcr-of-pcarl, v, ,3(>«j; des- cription of the clamp, v, Shells, on fossil, ii, 1 4H ; beds o; ter, ll<); in Northamptoushire, i ,o Ships, e£fect> of ligfatuiog on, iv, ;jt,s Ship icornif description of the, \ INDEX. Shireburn castle, phoenomenon at,ii,53 Shoal of pumice-stones, iv, 165 Shoerls, or volcanic glass described, i, 511, 518 Shropshire, mines in, ii, 3*^2 SJwu-ers, \ulcanic, iv, l6l ; of h'shes,l66 Siberia, bones in the rivers of, ii, 178, 195; on the mines of, ii, 286 Sicilian diver, account of the, v, 370 Sicily, earthquakes in, ii, 6, 59 Sidereal revolution, duration of, i, 147 Sierni /eomdiiountainsdescribed, ii,429 Silk-u-orm, natural history of the, v, 407 ; on the culture of, 410 Silrer mines in Norway, ii, 284 ; in Potosi, 292; method of working, 293 ; in Ireland, .3-27 ; on fulminat- ing, vi, 185 Silver-tree, method of making, vi, 327 Simoom, a pestilential wind, iv, 233 Sinai, description of mount, ii, 425 j on the desert of, iv, 80 Siren, natural history of the, v, 564 Sirocco, a destructive wind, iv, 223 Skidi!au; in Cumberland, described, ii, 444 Shy, on the bine colour of the, iv, 5 ; on the clearness of the, 69 ; on lights in the, 427 Skit-lark, natural history of the, v, 632 Snaefell Jokul, volcanic peak of, i, 461 Snake, description of the rattle, v, 566; the horned, 577; the hooded, 584 Snow, nature of, iv, 166; quantity of water equal to, 168; mode of forma- tion of, 170; red, 172, 3; avalanches of, 175; a family buried in the, 177; of the appeiinines, exhalations on, 501 Snowdon, in Wales, described, ii, 443 Solander, Dr. anecdote of, iv, 87 Solar agency in cometic phenomena, i, 135; iris, a remarkable, iv, 528 ; phosphori, vi, 107 tSW/atem, nearNaples, account of, i,509 j Solids, expansion of, iv, 51; on the fusion of, 56 Xulittion of water in air, iv, 145 Solway moss, irruption of, ii, 139 Somma, description of mount, i, 366 Xauffrieres, in the West Indies, i, 492 Sounds, on the velocity of, iv, '^S7; on the nature of, 'i.i.i S"fi polar regions, cold of, iv, 86 Spain, minerals of, ii, 283 ; mountains of, 419; on the wines of, v, 77 Speculum metal, composition of, vi, 29 1 Spiders, natural history of, v, 46»> , M! k spun from tie, 460 ; flight of th Sponges, natnral history of, v, 355 .tyoiilaucort* illumination, vi, 128 Spots, on the solar, i, 44 Spouts, water, on, iv, 262, 269 Spunk, inflammability of, vi, 100 Staffa, description of the isle of, ii, 97 Stay's horns, enormous, ii, 174 Stanhope, lord, on the returning stroke, iv, 336 Star-fish, natural history of, v, 364 Stars, nature of the fixed, i, 58 ; rela- tive situation of double, 1 13 ; twink- ling of the, 185; observations on the, 189 ; distances of the, 190 ; light of the, ib. ; visible in London, 203; on shooting, iv, 492 Statuary metal, composition of, vi, 285 Statues, remarkable, ii, 243, 251 Steel, method of casting, vi, 293 Stellar nebulae, observations on, i, 103 Sterlet, natural history of the, v, 537 Stone-henge, on the temple of, iv, 876 Stones, of phosphorescent, ii, 385 ; on sonorous, 386; remarkable hail, iv, 182, 184; shower of, 459; history ot% meteoric, 468 ; analysis of, 473 ; ori- gin of, 475; on burning, iv, 425 Storms, violent one in Denbighshire, iv, 155; at liipponden, 156; in Sus- sex, 157 ; remarkable hail, 182, 184 ; on the course of, 203: extraordinary thunder, iv, 312, 36l Strata of the earth, i, 233 ; on basaltic, 273 ; of rocks, 327 Streaming, on luminous, iv, 414 Stroke, on the returning, iv, 336 Stromboli, account of, i, 436 Stukely, Dr. on earthquakes, ii, 13 Sturgeon, natural history of the, v, 534 SttifflTMMDtphoQnosjMM of the globe, i, 319; quarries, ii, 113; trees, 154, 158; horns, 174; ruins, 258, 9 Sucker, description of the, v, 5.S2 Sui-twu of the atmosphere, iv, 29 Sitdbttry, parhelia seen at, iv, 523 Sugar, natural history of, v, 78; on niHple, 84; of btet root, 85 ; chemi- cal properties of, 87 ; of v* ln-.i- preparation of the caudy of, loo - Sulphur, on the mountains of, i, 458; hills of in the West Indies, 4<> I, b.i.I of, n. Sulphuri-oiiis vapour*, on, i, Sumatra, remarkable fog in, iv, \:>:1 >'«», nature of tin-, i, -13; on the spots in the, 44; atmosphere of, .r> 1 ; As- tronomical elements of, I4">; dis- tance^ of I ho planets from the, 147 j particular remarks on, 191 >'MH.V, on mock, iv, 521,521; in fire- works, vi, 244 Surrey, phenomenon observed in, ii, 48 SmpMUoMM river described, iii, 4 2 <; agitation of waters in, ii, 48 j meteors observed in, iv, 420 Swift, natural history of the, v, 638 Switzerland, earthquake in, ii, 21 Sn-ord, meteor like a, iv, 441 Sword-Jish, natural history of, v, 486 Sycamore of the scriptures, v, 47 Symbols, of astronomical, i, 35 Sympathy in two clocks, iv, 547 Synthesis, observations on, i, 17.~> Syria, prevailing winds in, iv, 191 ^•/rians, their letters, vi, 374 Systems of natural history, v, 5 Szelitze'in Hungary, excavation at,ii,79 Table hill, at the Cape of Good Hope, ii, 430 Tables, on the Indian, i, 5 Tabor, description of mount, ii, 425 Tacitus, letter of Pliny to, i, 336 Tallow tree, account of the, v, 308 7 'amarind tree, description of the, v, 143 Tanais, on the ancient, iii, 21 Tangier, earthquake at, ii, 4() Tannin ff, virtue of moss in, ii, 142 TH n lulus, on the cup of, iii, 81, 87 Tiirunta, in Arabia, passage of, ii, 449 Tarantula spider, account of, v, 467 Tasso, in Africa, swallowed up, ii, 42 Taurus, description of mount, ii, 424 Tm, natural history of, v, 101 ; me- thod of cultivating, 103 } on the trade of, lo/i Teak tree, description of the, v, 300 Tee*, fall of the, iii yjl Telescope, discovery of the, i, 21 Telescopic planets, on the, i, 161 Temperature of the earth, iii, 107; of the sea, 3.02; of the atmosphere, iv, 31; definition of, :,.\ Tunpest, a remarkable, iv, 24 Tenerijf, description of, i, 470 ; ar< -otini of the pc.ik of, 471 } on the \\ini » of, v, 7 t Terra australis, account of, iv, ul uci'J'u, >t», on the climate of, iv,S7 Terrestrial ;ixis, imitation of tin . Tesselateil pa\em< \\i discoven-i!, Tixtnrrii'.is \\on.is described, v, Trtuan, earthquake at, ii, 40 Thalcs, account of, i, 7 Thames, remarkable .million of \\\r, ii, .">! ; inundation of the, 147; trees under the, 154 ; description oi. Than, on the lake of, iii, 243 Theatre, discovery of an ancient, ii, 242 Thermometer, principles of the, iv, 53 Thibet, mountains in, ii, 426 Thomas, account of the isle of St. iv, 83 Thorn apple, account of, v, 260; it* virtue in asthma, 2*>j Thrush kind, natural history of, v, 618; the song, 621 ; the mimic, 624 Thnle, on the ultima, i, 446; the south- ern, iv, 93 Thunder, on the electricity of, iv,300; storms, remarkable, 312, .i6; an extraordinary one, 255 ; the New- tonian system of, iii, 317 ; hypothesis of St Pierre ou, 329; on tfie aerial, iv, 40 Tin mines, in Cornwall, account of the, ii, 275; mode of working, 320; nature and properties of, vi, 295; on the purity of,297; applied to glass,325 Tinder-box, the pneumatic, , Tinian, account of the isle of, iv, 83 Tinniny copper, method of, vi, 3ol, iron, 307 Tivoli, on the town of, iii, 69 Toad, natural history of the, v, 56l ; fish, account of the, 531 Tobacco, on the infusion of, v, 231; etnpyreumatic oil of, 234 ; descrip- tion of, 303; machine for winding,307 Tola, on the balsam of, v, IK I Tiimlnii'too, on the caravans of, ii, 485 Topical winds, on, iv, 232 Toplitz, agitation of the baths of, ii,57 Turnadoes, account of, iv, 248 INDEX. Torpedo, of the electrical, v, 488 Torre del Greco, fate of, i, 383 Torricflli, discoveries of, i\ Tarrid :oiie, description of, i, 3 14 j heat of, iv, 197 Tortoise, dest riplion of the land, v, 542 7 'imrlwood tinder-box described, vi, 99 'J'niirneforfs botanical system, v, 12 Tviinnaline, electrical properties of the, ii, 272 Trade winds, observations on, iv, 185 ; account of, v, 207 Trajan, the column of, vi, 501 Transition, formations on, i, 324 Trees, on subterranean, ii, 133, 154, 158 ; extraneous substances in, v, 313} on metallic, vi, 326 Trent, course of the river, iii, 35 Trichoda, description of the, v, 350 Trinidad, pitch lake in, iii, 150 Tripod, a beautiful, ii, 250 Troat, the hot springs at, iii, 1 17 Tropical sea winds, iv, 2 1 1 j land winds, •219 Tropics, definition of, i, 311 Trout, natural history of the, v, 523 Tnninii, description of various, vi, 505 Tmtbridye, waters agitated .it, ii, 51 ; description of,iii, 177} on me spring of, 17S Tuiif/urayua, a mountain hi Mexico, i, 490 Turf-bogs of Ireland, iii, 2^9 Turpentine, various kinds of, v, 172; on the oil of, 175 Tuteuag, account of, vi, 282 Ttciliyht,ott the phenomenon of, i, 188 Twinkling of the stars, on the, i, 165 Tyclio lirahe, account of, i, 23 Tyjihun, derivation of, iv, 216 Ulster, gold found in, ii, 327 I Isicater, description of^ iii, 244, 258 1'nitcd States, mineralogy of, ii, 313 i'pas antiar, description of, v, 238; of lht- Bt.h. in, 279 I Yttwa, account of the lake of, iii, 236 / 'ranioiti-g, on the observatory of, i, i>4 Uranus, discovery of the planet, i, 146 ; elements of, 161 ; satellites of, 168; on the climate of, 194 / ;/, Mr. liis :islroi.omi Vine, natural history of the, v, 70; main. •:<><.ii>. nt of, 7 1 Vineiftii-ut: in Britain, v, 72 Viigini.; Ca- naries, 469; Isle of Bourbon, 477; Mexico, 479; New (Jrenada, 485; West Indies, 491 Volya, description of the, iii. Volta, on the electricity of, vi, 43 ; hit experiment!!, 47 INDEX. Volrrr, a genus of animalcules, v, 350 Vowi/r nut, account ot'll'.c. \, -jii2 VnrticrtliL, natural histor\ ofthe, v,3-18 !'<» -tit-ex, on the ('artesian, i, ,'J.i \'u!e4 I'nltiin, n;itnr;il history of the, v, 585 Walis, inoiin tains of, ii, 4 ! ' H /(// ofChina, description ofthc, vi,480 War improves geography, i, 301 lVrtr.S : .extraordinary agitation of, ii, 47,58; on foreign mineral, iii, l6l ; methods of, analysing, 178; principles con- tainc/1 in, 179; different classes of, 182 ; s synoptical table of, 212 Waterspouts, general account of, iv, 256; genuine ones, 262; mimic, 2C7 Wares, on the motion of, iii, 359; ef- fects of oil on, 36 1 War, on painting in, vi, 411 ; revival of, 425; improvements in, 429 Waxtree, description of, v, 308 ; a new vegetable, 310 Wecdens well, description of, iii, 176 Wells, remarkable one in Devonshire, iii, 85; Gigglcswick, 86, 92; at U igan, 147 ; Brosely, 148 ; in Cler- inont, lf>9; Bristol, 175; St. \\ in* •- fred's, ihid ; Weedcn's, 1/6; Bux- ton, ibid ; Tun bridge, 177 riini systetQ of mineralogy, i,2SO Wesel, course of the, iii, 26 West Judirt, volcanic phenomena in, i, 4!U ; mountains in, ii, 433 Wetter lake, description of, iii, 233 Wheat, effect of thunder on, iv, 312; sugar extracted from, v, 92 Wliirln-inds, observations on, iv, 248 Whixton's theory of the earth, i, 255 Whispi r iii rj galleries, account of, iv, 544 Wkiti iiiounlains in America, ii, 432 W hitehavcn, account of the coal works at, ii, 340 Wichlmr Coppermine describe,!, ii, . n'ohl iii, Wiaan we.ll, Lancashire, described, iii, 147 W intlow glass, manufacture of, vi, 161 , account of the cape of the,ii,4.'.0 Winds, on the nature and origin of, iv, 185; on the velocity of, inti; of trade, 1<>9; intensity of, J'i.( ; pi r- enial, 207 ; toj.ieal, •_'!!; lln sian,'217 ; KhOinaeen, 212~' ; >i 223 •, long-shore, 22 1 ; land an 2,'.»; thirniiittan, '>-2(> ; topical or toral, 232; simoom, 233; u.. 234; occasional, 235; transports seeds, v, 29 [iii, 175 Winifred's well, Flintshiro, described, Wines, on the varieties of, v, 73 Winters, remarkably severe, iv, 117 Wood, description of petrified, ii, 148; iii, '275 Wood, art of sculpture in, \ i. Woodpecker, natural hist, of the, v, ;"<)7 Woorara, a vegetable poison, describ- ed, v, 236 Worlds, conjectures on the celestial, i, 36- Worms, natural history of, v, 345 ; ofthc ship, 367 ; shell, 375 ; intestinal, 37<3 Wrehin in Shropshire, account of, ii,4 42 Wren, natural history oflhe, v, < Writing, origin and progress of, vi, 343 ; claims to the invention of, 363 Wrunvch, description of, v, f>41 Xerjrrs, Ii is bridge of boats, vi, :>\7 Xisitthnif, tradition of. i, 246 Year, on the Egyptian, i, 203 Vord'ts cave in Yorkshire, iii, i Yorkshire, submarine forest in, ii, l.">ft ; ancient town in, 223 ; meteor ob- served in, iv, 441 Yverdnn lake, description of, iii, Q36 '/.nmbnrari, his ;rrial voyage, vi, 7 I Zcitlandi\;\\, account of the new , Y.i-mcnt copper, properties of, ii, 315) Zinc, applied in galvanism, vi, 4 . , history of, 214 ; description «•!. 'Zirkinztr lake, description of, iii, !)7 Zodiac, on the signs of the, i, 3 Zoophytes, natural history of, ii, 148 ZdOfthiftic worms described, v, 352 Zin/der-Zee, formation ofthc, ii, 1 r. I1MS. R. Wilks, Printer, 89, Chancery- Lane, London. CONTENT'S OF YOU MI: vi. PART II. GALLERY OF ART, BOOK f . CHEMISTRY. rhap. Page I. On the Rise and Progress of Chemistry . I II. On Electricity . . . 17 SECT. I. Introduction . , ib. ii. Electricity in Equilibrium .. . ib. iii. Electricity .in Motion . . 25 iv. Galvanic, or Voltaic Electricity . 43 III. Magnetism 53 IV. Aerostation : including the Principles, History, and Management of Balloons . 63 SECT. i. Principles of Aerostation . . ib. ii. History of Aerostation . . 64 iii. Construction of Balloon? . . 80 V. Ga*s Lights ... 88 SECT. i. Introductory Remarks . . ib. ii. Application of the Gass from Coal to Economical Purposes ... 8J> VI. Phosphorus of Kunckel Phosphoric Bottles and Matches VII. Pneumatic, or Touchwood Tinder-box VIII. Phosphorescence: or Spontaneous Illumination, Animal, Vegetable, and Mineral . 107 SECT. i. Solar Phosphori . . . ib. ii. Calorized Phosphor! . . HO iii. Animal and Vegetable Phosphori . ib. IX. Spontaneous Combustion . . I'-S X. Chemical Affinity XI. On Crystallography . • . 14'2 XII. Manufacture of Glass . . 153 SECT. i. History of the Discovery . • ib. ii. Properties of Glass . iii. Manufacture of Glass : • 161 YOL. Tit b iv CONTENTS OF VOL. VI. (Imp. SECT. iv. Rupert's Drops : Batavinn Tears : Bologuian Phial 166 XIII. On Ciuiipowd.-r . . Ifis SECT. i. Of the Time when Gunpowder was first discovered ib. ii. Composition and Analysis of Gunpowder 174 XIV. Fulminating Powders . 184 SECT. i. Common Fulminating Powder . ib. ii. Fulminating Gold iii. Fulminating Silver . . ib. ivj Fulminating Mercury . 186 T. Azotane, or the Detonating Substance of M. Dulong 2O7 BOOK II. PYROTECHNY, or ART of constructing FIRE-JVORKS. I. Construction of the Cartridges of Rockets C 1C II. Composition of the Powder for Rockets and the Manner of filling them . . CIS III. On the Ascent of Rockets into the Air '221 IV. Brilliant Fire and Chinese Fire . <222 V. Of the Furniture of Rockets . . 224 SKCT. i. Serpents . . . 225 ii. Marroons . . . 226 iii. Saucissons . ib. iv. Stars . . . 227 v. Showers of Fire . 229 vi. Sparks . . . 230 vii. Golden Rain . . . ib. VI. Rockets of peculiar Construction . <2.>l SECT. i. Courantains, or Rockets which Fly along a Rope ib. ii. The same made to turn round at the same time 232 iii. Rockets which burn in the Water . jfo. iv. Figures represented in the Air by means of Rockets 234 v. Rockets which ascend in the form of a Screw 235 VII. Of Globes and Fire-Bails . . ib; SKCT. i. Globes which burn in the Water . 035 ii. Globes which Leap or Roll on the Ground 237 iii. Aerial Globes or Bombs * . 238 VIII. Jets of Fire . . . 049 SECT, i. Fires of different Colours . . 242 ii. Fa->(e for representing Animals and other Devices in Fire . . . 243 iii. Sun«, fixed and moveable . 244 CONTENTS OF VOL. VI. V BOOK III. Of METALLURGYjtnd the ARTS connected zcith it. Chap. Pag* I. Calamine ; Blende, or Black Jack ; Zinc ; and Brass 246 II. On Auricbalcum, Orichalcum, or the Brass of the Ancients . . 272 III. On Gun-Metal ; Bronze, or Statuary-Metal ; Bell- Metal; Pot-Metal; and Speculum-Metal, or Metallic Mirrors : . 283 IV. On Tinning Copper; Tin; Pewter . 294 V. On Gilding in Or Moulu ; Use of Quicksilver in ex- tracting Gold and Silver from Earths ; Silver- ing Looking-Glasses . : 31 5 VI. Metallic Plants or Trees 325 BOOK IV* POLITE ARTS, or those connected with LITERATURE. I. Paper-making . . . 328 II. Origin and Progress of Writing . 342 SECT. i. On Hieroglyphic and Picture Writing . ib. ii. On the Origin of Letters and Invention of Alphabets 35O iii. Antiquity of Writing, and the Claims of different Nations to the Honour of its Invention 363 ir. Instruments for Writing with . 383 T. Inks . , . 385 vi. Origin and Progress of Printing . 398 III. Imitative Arts : comprising Designing, Painting, Enamelling, Sculpture, Pottery, and Porce- lain-Modelling . . 408 SECT. i. Knowledge of the Ancients in respect to the Imita- tive Arts ... . ib. ii. Painting in Glass . 412 iii. Enamelling . . . 419 ir. Encaustic Painting . . 425 T. Painting of Paper-Hanging . 433 ri. Calico^Printing . . 437 vii. Engra?ing . . 440 Tiii. Sculpture . . 445 ix. Potttry and Porcelain . . 452 IV. Burning Mirrors . . 458 Yi CONTENTS OP VOL. VI. Chap. V. (I'UK rul Architecture and Mechanical Sciences SECT. i. Architecture and Mechanical Sciences of the Ancients il>. ii. Comparative view of the Architecture ofditf't rent Ayes 471 iii. Labyrinth* . . -177 iv. Great Wall of China . . 480 T. Temple of Klephanta . . 481 vi. Temple of Juggernaut vii. INlorai: or Cemetery and Temple of the Australa. sian Islands . . 491 viii. Architectural Remains at Mylassa . 496 i.T. Temple of Heliopolis, or BaLbec . 49S> x. Magnificent Ruins of Palmyra 504 xi. Splendid Ruins of Persepolis . 510 xii. Ruins and present Appearance of Jerusalem 519 xiii. Interesting Ruins of the Plain of Troy 637 xir. Sculpture and Architecture of Athens 548 TV. Magnificent Remains or Ruins in Egypt . 560 xvi. Porcelain Tower at Nankin . ib. xvii. Colossus of Rhodes . . 561 xviii. Italian Monuments and Architecture ib. six. Temple of Sancta Sophia at Constantinople 562 xx. Monastery of Monfserrat . 563 xxi. Stone-henge . . . 5G4 xxii. Ttfinuli : including Barrows, Cairns, Cromlechs, Kist-vaens, Logan or Rocking-stones, and similar Monumental Remains . . 566 1. Barrows . , 567 2. Cairns . . 572 J. Cromlechs . . 573 4. Rocking.stoncs. Logan- stones 574 VI. Xavu! Architecture , . 575 V.< r. i. Ark of Noah . . . 57Q ii. Galley of Hiero . . . 579 iii. Xerxes's Bridge of Boats over the Hellespont 5SO iv. Spectacle of a Sea-fight at Rome . 584 VJ I. Bridges and Light- Mouses . . 58.5 i. Bridges most curious or interesting . ib. ii. Light houses : exemplified by those of Phasclus, Pharos, and the Kddystone Kocks . 589 VIII. Chronological Table of Mechanical Inventions 5 then cultivated as a separate branch of science, or distinguished in its application, from a variety of other arts which must have been exercised for the support and convenience of human life. All of these had probably some dependence on chemical principles, but they were then, as they are at present, practised by the several arti>ts without their having any theoretical know- ledge of their respective employments. Nor can we pay much attention in this inquiry to the obscure accounts which are given of the two great Egyptian philosophers, Hermes the elder, supposed to be the same with Mizraim, grandson of Noah ; and Hermes, surnamed Trismegistus, the younger, from whom chemistry has by some been affectedly called the Hermetic art. The chemical skill of Moses, displayed in his burning, reducing to an impalpable powder, and rendering potable the golden calf in the wilderness, has been generally extolled by writers on this sub- ject ; and constantly adduced as a proof of the then flourishing state of chemistry amongst the Egyptians, in whose learning he is said to have been well versed. If Moses had really reduced the gold of which the calf consisted, into ashes, by calcining it in the fire ; or made it any other way soluble in water, this instance would have been greatly in point; but neither in Exodus nor in Deuteronomy, where the fact is mentioned, is there any thing said of its being dissolved in water. The enemies of revelation, on the other hand, conceiving it to be impossible to calcine gold, or to render it potable, have produced this account as containing a proof of the want of veracity in the sacred historian. Both sides seem to be in an error ; Stahl, and other chemists, have shewn that it is possible to make gold potable, but we have no reason to coo. elude that Moses either used the process of Stahl, or any other chemical means for effecting the purpose intended — " he took the calf which they had made, and burnt it in the fire, and ground it to powder, and strewed it upon the water, and made the children of Israel to drink of it t." Here is not the least intimation given of the gold having been dissolved, chemically speaking, in water ; it was stamped and ground, or, as the Arabic and Syriac versions • S«r Delaval's ingcnioug Inquiry into the Cause of the Changes of Colours, Pref. LTI. ; and Dutcns' learned Inquiry into the Discoveries attributed to thr Modrnu, p. 241. t Eiod. xxxii. 90. OP CHEMISTRY. 5 have it, filed into a line dust, and thrown into the rirer, of which (Tie children of Israel used to drink : part of the gold would re. main, notwithstanding its greater specific gravity, suspended for a time (as happens in the washing«of copper and lead ores), and might be swallowed in drinking the water ; the rest would sink to the bot- tom, or be carried away by the flux of the stream. Nevertheless, though nothing satisfactory can be concluded con. cerning the Egyptian chemistry, from what is said of Moses in this instance; yet the structure of the ark, and the fashion of Aaron's garments, clearly indicate to us that the arts of manufacturing me. tals, of dying leather red, and linen blue, purple, and scarlet ; of distinguishing precious stones, and engraving upon them, were at that time practised in a very eminent degree*. The Israelites had unquestionably learned these arts in Egypt, and there is great rea. son to suppose, not only that learning of every kind first flourished in Egypt, but that chemistry in particular, was much cultivated in that country, when other sciences had passed into other parts of the world. Pliny, in speaking of the four periods of learning •which had preceded the times in which he lived, reckons the Egyp, tian the first: and Suidas, who is thought to hare lived in the tenth century, informs us, that the Emperor Diocletian ordered all the books of chemistry to be burned, lest the Egyptians learning from them the art of preparing gold and silver, should thence derive re. sources to oppose the Romans. It is worthy of notice, that Suidas uses the word chemistry in a very restricted sense, when he interprets it by — the preparation of gold and silver; — but all the chemists in the time of Suidas, and for many ages before and after him, were alchemists. The edict of Diocletian in the third century, had little effect in repressing the ardour for that study in any part of the world, since we are told, that not less than five thousand books, to say nothing of manuscripts, have been published upon the subject of alchemy, since his timef. At what particular period this branch of chemistry, respecting the transmutation of the baser metals into gold, began to be dis. tinguished by the name of alchemy, cannot be determined. An author of the fourth century, in an astrological work, speaks of the science of alchemy as well understood at that time ; and • Exod. xxvi. and xxviii* + Chem. Walleri, p. 40. • f 0 K1SE AND PROGRESS this is said to be the first place in which the word alchemy is u-« * But Vossius asserts that we ougut, in the p'ace here re. ferred to, instead of alchemia, to read chenia-r : be this as it may, we can have no doubt of al hernia bein. compounded of the Arabic al (the) .jvl ehemia, to denote excellence an>i sujjerioriy, as in al. manack, al Koran, and oth»T words. Whether the Greeks invent, ed, or received from the F'gyptians, the doctrine concerning the transmutation of metals, or whether the Arabians were the first •who professed it, is uncertain. To change iron, lead, tin, copper, or quickshvei into gold s» e.ns to be a problem more likely to ani- mate mankind to attempt its solution. th»r! ei.her that of squaring the circle, or of finding out p^r^t -iu.il motion ; and as it has never yet been prov. d, , r .ap never ca.i oe proved, to be an impossible problem, it ought not to be esteemed a matter of wonder, that the fust chemical books we meet with, are almost entirely employ t d in alchemical inquiries. Chemistry, with the rest of the sciences, being banished from the other parts of the world, took refuge among the Arabians. Geber, in the seventh, or as some will have it in the eighth, and others in the ninth century, wrote several chemical, or rather alchemical books, in Arabic. In these works of Geber are contained such useful directions concerning the manner of conducting distillation, calcination, sublimation, and other chemical operations; and such pertinent observations respecting various minerals, as justly seem to entitle him to the character, which some have given him, of be- i:.i ;iit Mt'Kr of chemistry; thou h, in one of the most celebrated of his works, he modestly acknowledges himself to have done lit. tie else than abridge the doctrine of the ancients, concerning the transmutation of metals J. Whether he was preceded by Mesue and Rhazes, or followed by them, is not in the present inquiry a matter of much importance to determine; since the forementioned physic in. >«:, as well as Avicenna, who, frera all accoi nts. was pos- terior to Ci'lnr, speak of many chemical preparations, and thus * Jul. Fermi. Mater. Artronnmicon. Lib. III. c. 15. f Voss. t(\mo. Vox Alchcmia. J Totam n oil ram metallorum transmutandorum scientiam, qunrn rz libris antiqunrum philosnphorum ahbreviavimus rompilat our <1iv«Tya, in nostris volu- minibus hie in unam summum redegiinu*. tirhri Alch. cap. I, edition by Zctznrr, in 1512. In Tancken's edition, in 1681, the words, metallorum traos* mutandorum, are omitted. OF CHEMISTRY. 7 thoroughly establish the opinion, that medical chemistry, as well as alchemy, was in those dark ages well understood by the Arabians. Towards the beginning of the thirteenth century, Albert the Great, in Germany, and Roger Bacon, in England, began to cul. tivate chemistry with success, excited thereto, probably by th# perusal of some Arabic books, which about that time were trans, lated into Latin. These two monks, especially the latter, seem to have as far exceeded the common standard of learning in the age in which they lived, as any philosophers who hare appeared in any country, either before their time or since. They were succeeded in the fourteenth and fifteenth centuries, by a great many eminent men, both of our own country and foreigners, who, in applying themselves to alchemy, made, incidentally, many useful discoveries in various parts of chemistry : such were Arnoldus de Villa Nova, in France; our countryman George llipley ; Raymund Lully, of Majorca, who first introduced, or at least more largely explained, the notion of an universal medicine; and Basile Valentine, whose excellent book, intitled Cttrrus Antimonii Triumphal?*, has con. rributcd more than any thing else, to the introduction of that most useful mineral into the regular practice of most physicians in Europe ; it has given occasion also to a variety of beneficial, as well as (a circumstance which might be expected, when so ticklish a mineral fell into the hands of interested empirics), to many per- nicious nostrums. To this, rather than to the arrogant severity with which Basile Valentine treats the physicians, his cotempora- ries, may we attribute the censure of Boerhaave ; who, in speak, ing of him, says, " he erred chiefly in this, that he commended every antimonial preparation, than which nothing can be more foolish, fallacious, and dangerous ; but this fatal error has infected every medical school from that time to this*." The attempting to make gold or silver by alchemical processes, had been prohibited by a constitution of Pope John the 22d, who was elevated to the pontificate in the year 1316 1; and within about one hundred and twenty years from the death of Friar Bacon, the nobility and gentry of England had become so infatu. ated with the notions of alchemy, and wasted so much of their sub. stance in search of the philosopher's stone, as to render the inter, position of government necessary to restrain their folly. The fol- • BoerN. Ch. vol. 1. p. 18. t Kirch. MUD. Sub. 1. xi, sect, iv. c. 1. • 4 8 HISE AND PROGRESS lowing act of parliament, which Lord Coke calls the shortest he ever met with, was passed 5 II. 4. " None from henceforth shall use to multiply gold or silver, or use the craft of multiplication ; and if any the same do, he shall incur the pain of felony." It has been suggested, that the reason of passing this act, was not an ap- prehension lest men should ruin their fortunes by endeavouring to make gold, but a jealousy lest government should be above asking aid of the subject. " After Raymund Lully, and Sir Georg» Ripley, had so largely multiplied gold, the lords and commons, conceiving some danger that the regency, having such immense treasure at command, would be above asking aid of the sub. ject, and might become too arbitrary and tyrannical, made an act against multiplying gold and silver*." This act, whatever might be the occasion of passing it, though it gave some obstruction to the public exercise of alchemy, yet it did not cure the disposition for it in individuals, nor remove the general credulity ; for in the 35 H. 6, Letters patent were granted to several people, by which they were permitted to investigate an universal medicine, and to perform the transmutation of metals into real gold and silver, with a non-obstante of the forementioned statute, which remained in full force till the year 1689, when being conceived to operate to the discouragement of the melting and refining of metals, it was for. mally repealed +. The beginning of the sixteenth century was remarkable for a great revolution produced in the European practice of physic, by means of chemistry. Then it was that Paracelsus, following the steps of Basile Valentine, and growing famous for curing the vene- real disease, the leprosy, and other virulent disorders, principally by the means of mercurial and antimonial preparations, wholly re. jected the Galenical pharmacy, and substituted in its stead the che. mical. He had a professor's chair given him by the magistracy of Basil, was the first who read public lectures in medicine and che. mistry, and subjected animal and vegetable, as well as mineral sub. stances to an examination by fire. It seldom happens that a man of but common abilities, and in * Opera Mineralia explicatn, p. 10- f Mr. Boyle is s-ii.l liy hit interest to have procured the repeal of this singu- lar -i.itutr, and to have been probably induced thereto, in consequence of his having been persuaded of the possibility of the transmutation of metals into gold. See his Life, prefixed to the folio edition of hit works, p. 85. OF CHEMISTRY. 9 the most retired scenes of lifV, observes such a strict uniformitv of conduct, as not to afford pn-judice and partiality sufficient material* for drawing his character in different colours ; but such a great and irregular genius as Paracelsus, couid not fail of becoming alike, the subject of the extremes of panegyric and satire. He has accord, ingly been esteemed by some, a second Esculapius ; others have thought that he was possessed of more impudence than merit, and that his reputation was more owing to the brutal singularity of his conduct, than to the cures he performed. He treated the physi- cians of his time with the most sottish vanity and illiberal insolence, telling them, that the very down of his bald pate, had more know- ledge than all their writers; the buckles of his shoes more learning than Galen or Avicenna, and his beard more experience than all their universities*. He revived the extravagant doctrine of Ray. mund Lully, concerning an universal medicine, and untimely sunk into his grave at the age of forty. seven, whilst he boasted himself to be in possession of secrets able to prolong the present period of human life, to that of the antediluvians. But in whatever estimation the merit of Paracelsus as a chemist may be held, certain it is, that his fame excited the envy of some, the emulation of others, and the industry of all. Those who at- tacked, and those who defended his principles, equally promoted the knowledge of chemistry ; which from his time, by attracting the notice of physicians, began every where to be systematically treated, and more generally understood. Soon after the death of Paracelsus, which happened in the year 1541, the arts of mining and fluxing metals, which had been prac- tised in most countries from the earliest times, but had never been explained by any writers in a scientific manner, received great il- lustration from the works of Georgius Agricola, a German phy- sician. The Greeks and Romans had left no treatises worth men- tioning upon the subject; and though a book or two had appeared in the German language, and one in the Italian, relative to metal- lurgy, before Agricola published his twelve books De Re Metallica, yet he is justly esteemed the first author of reputation in that branch of chemistry. Lazarus Erckern (assay.master general of the empire of Ger- many) followed Agricola in the same pursuit. His works were • Preface to hii book entitled Paiagranum, where there is more in the same style. 1O RISK AND PROGRESS first published at Prague, in 1574, and an English translation of them by Sir John Pettus, came out at London, in 1683. The works of Agricola and Krckern are still highly esteemed, though several others have been published, chiefly in Germany, upon the same subject, since their time. Amongst these we may reckon Schindler's Art of Assaying Ores and Metals ; the metallurgic works of Orscliall ; the works of Henckell ; of Schutter ; of Cra. mer; of Lehman; and of Gellert. Germany, indeed, has for a long time been the great school of metallurgy for the rest of Europej and we, in this country, owe the present flourishing condition of our mines, especially of our copper mines, as well as of our brass manufactory, to the wise policy of Queen Elizabeth, in granting great privileges to Daniel Iloughsetter, Christopher Schutz, and other Germans ; whom she had invited into England, in order to instruct her subjects in the art of metallurgy. It was not, however, till towards the middle of the last century, that general chemistry began to be cultivated in a liberal and phi- losophical manner. So early as the year 1645, several ingenious , persons in London, in order to divert their thoughts from the hor- rors of the civil war, which had then broken out, had formed themselves into a society, and held weekly meetings, in which they treated of, what was then called, the new, or experimental philo- sophy. These meetings were continued in London, till the esta. blishment of the Royal Society, in 1662 ; and before that time, by the removal of some of the original members to Oxford, similar meetings were held there, and those studies brought into repute in that university. Mr. Boyle, who had entered upon his chemical studies about the year 1647, was a principal person in the Oxford meetings ; he published at that place, his Sceptical Chemist, in 1661, and by his various writings and experiments, greatly contributed to the introducing into England, a taste for rational chemistry. Next to Boyle, or perhaps before him as a chemist, stands his cotemporary, the unfortunate Beccher, whose Physica Subter. ranea, justly entitled opus sine pari, was first published in 1669. After having suffered various persecutions in Germany, he came over into England, and died at London, in 1682, at the age of 57. He resided some time before his death in Cornwall, which he calls the mineral school, owning that, from a teacher, he was there be. come a learner. IK- was the author of many improvements in the manner of working mines, and of fluxing metals; in particular, he OF CHEMISTRY". 11 first introduced into Cornwall, the method of fluxing tin by means of the Same of pit. coal, instead of wood or charcoal *. L*TII« ry's yry accurate course of practical chemis'ry, appeared in 1675. Glauber's works had been published at different times, from 1651 to 1661, when his tract, entitled Philosophical Furnaces, came out \t \msterdam, Kunckel died in Sweden, in 1702 ; he had prrtv-tis d chemistry for abore 50 years, under the auspices of the elector of Saxony, and of Charles XI. of Sweden. He wrote his chemical observations in the German Lan uage, but had them translated i:ao Litin, in the year 1677: the translation is dedicated by its author, o our Royal Socu ty. They *ere aft. r wards trans- lated ,nt i Kn^h-ii, in 17<;}. Having bad the supenntendency of several glass-nouses. h»- had a fine opportunity of making a great variety of experiments in that way ; and I have been informed by our enamellers, and makers of artificial gems, that they can depend more upon the processes and observations i» Kunckel, than of any Other author upon the same subject. The chemical labours of these and many other emin< nt men, too numerous to mention, were greatly forwarded by the establishment of several societies, for the encouragement of natural philosophy, which took place in various parts of Europe ahout that period. The Philosophical Transactions, at London; the Histoire de 1' Academic Royale des Sciences, a< Paris; the Saggi d'Ksp'-rienze di Academia del Cimento, at Florence ; the Journal des S<;avans, in Holland; the Ephemerides Academiae Naturae Curiosorum, in Germany ; the Acts of the Academy of Copenhagen ; and the Acta Eruditorum, at Leipsic ; all theee works b -gan to be published within the space of twenty years from 1665, when our Royal So. ciety first set the example, by publishing the Philosophical Trans, actions. To these may be added, the works of the Academies * Beccher wrote his Alphabethum Mineral?, at Truro, in Coinwall. In 168?, not long before his death. In his dedication of this tract to Mr. Boyle, he has the following words :— *' ignis usus, ope flammanitn lithaiitruru u stannum et mineralia fundendi, Cornuhiae hactenus incognitos, sed a me introductus." — This accouot which Beccher piveg of himself, is not quite agreeable to what is advanced by an author every way qualified to come at the truth of this mat- ter. — " Necessity at last suggested the introduction of pit-coal for the smHting of tin ore; and, among others, 10 Sir B vil Cr.inville, of Stow, in I'M- r»;m \ , temp. Car. I. who made sevrml experiments, though without su c •«; neither did the effectual smelting of tin ore uith pit-con), take place till the second year of Queen Anne." Pryce's Miner. Cornob. p. 28?. RISE AND PROGRESS of Berlin, Petersburgh, Stockholm, Upsal, Bononia, Bourdeaux, Montpelier, Gottingen, and of several others which have been established within the course of the present century. Near a thousand volumes have been published by these learned societies, within less than 120 years. The number of facts which are therein related respecting chemistry, and every other branch of natural philosophy, is exceedingly great ; but the subject is still greater, and must for ever mock the efforts of the human race to exhaust it. Well did Lord Bacon compare natural philosophy to a pyra. mid ! Its basis is indeed the history of nature, of which we know a little and conjecture much ; but its top is, without doubt, hid high in the clouds ; it is " the work which God worketh from the be- ginning to the end," infinite and inscrutable. By the light which has been incidentally thrown upon various parts of chemistry, from those vast undertakings of public societies, as well as from the more express labours of Stahl, Newman, Hoff- man, Juncker, Geoffry, Boerhaave, and of many others equally worthy of commendation ; by the theoretic conclusions and syste- matic divisions which have been introduced into it ; from the didac. tic manner in which the students of this art have been instructed in every medical school; chemistry has quite changed its appear, ance. It is no longer considered merely in a medical view, nor restricted to some fruitless efforts upon metals; it no longer at. tempts to impose upon the credulity of the ignorant, nor affects to astonish the simplicity of the vulgar, by its wonders ; but is content with explaining them upon the principles of sound philosophy. It has shaken off the opprobrium which had been thrown upon it, from the unintelligible jargon of the alchemists, by revealing all its secrets, in a language as clear and as common as the nature of its subjects and operations will admit. Considered as a branch of physics, chemistry is but yet in its infancy : however, the mutual emulation and unwearied endea. vours of so many eminent men as are in every part of Europe engaged in its cultivation, will, in a little time, render it equal to any part of natural philosophy, in the clearness and solidity of its principles. In the utility resulting to the public from its conclu- sions, with respect to the practice of medicine, of agriculture, arts, and manufactures of every kind, it is even in its present state infe- rior to none. The uses of chemistry, not only in the medical, but in every OF CHEMISTRY. 13 economical art, are too extensive to be enumerated, and too noto. rious to want illustration ; it may just be observed, that a variety of manufactnres, by a proper application of chemical principles, might, probably, be wrought at a less expense, and executed in a better manner, than they are at present. But to this improvement there are impediments on every hand, which cannot easily be over, come. Those who by their situations in life are removed from any design or desire of augmenting their fortunes, by making discove. ries in the chemical arts, will hardly be induced to diminish them by engaging in expensive experimental inquiries, which not only re- quire an uninterrupted attention of mind, but are attended with the wearisomeness of bodily labour. It is not enough to employ ope. rators in this business ; a man must blacken his own hands with charcoal, he must sweat over the furnace, and inhale many a noxi- ous vapour, before he can become a chemist. On the other hand, the artists themselves are generally illiterate, timid, and bigoted to particular modes of carrying on their respective operations. Being nnacquainted with the learned, or modern, languages, they seldom know any thing of new discoveries, or of the methods of working practised in other countries. Deterred by the too frequent, but tnuch.to.be lamented examples of those, who, in benefiting the public by projects and experiments, have ruined themselves, they are unwilling to incur the least expense in making trials, which are uncertain with respect to profit. From this apprehension, as well as from the mysterious manner in which most arts, before the inven. tion of printing, and many still continue to be taught, they acquire a certain opini&trete^ which effectually hinders them from making improvements by departing from the ancient traditionary precepts of their art. It cannot be questioned, that the arts of dyeing, painting, brewing, distilling, tanning, of making glass, enamels, porcelain, artificial stone, common salt, sal ammoniac, salt-petre, potash, sugar, and a great variety of others, have received much improvement from chemical inquiry, and are capable of receiving much more. Metallurgy in particular, though one of the most ancient branches of chemistry, affords matter enough for new discoveries. There are a great many combinations of metals which have never been made ; many of which, however, might be made, and in such a variety of proportions, as, very probably, would furnish us with metallic mixtures more serviceable than any in use. The method of ex- 14 RISE AND PKOGRfcSS trading the greatest possible quantity of metal from a given quan. tity of the same kind of ore, has, perhaps, in no one instance ascertained with sufficient precision. There are many sorts of iron and copper ores, which cannot be converted into malleabl« metals, without much labour, and a great expense of fuel; it i> v-ry pro- bable, that by a well-conducted series of experiments, more mm. pendious wajs of working these minerals might be found out. Id our own times three new metallic substances hare been disro. vi- red *, and their properties abundantly ascertained by expert* ment; and it may reasonably be conjectured, that future experience will yet augment their number. Till Marggraaf shewed the m -inner of doing it, no metallic substance could be extracted from calamine, and all Europe was supplied with zinct either from India or from Germany. A manufactory of this metallic substance has not many years ago been established in our own country, and the copper works near Bristol hare supplied Birmingham with zinc extracted from calamine. Black-jack was not long since employed in Waleg for mending the roads ; its value is not yet generally known in Derbyshire ; but it is now well understood by some individuals to answer the purpose of calamine for the making of brass J. Mous. Von Swab, in 1738, was, I believe, the first person who distilled zinc from black-jack §; and a work which he erected, probably gave the hint to the establishes of our English manufactory : in- deed, I have been well informed, that they purchased the secret from him when he was in England. The various kinds of black lead, from which neither tin nor iron can at present be procured to advantage ; the mundicks, some cobalt ores, caw k, kebble, and other mineral substances, which are now thought to be useless, may some or time other, perhaps, be applied to good purpose. Cawk and kebble, which are found iu great quantities in mining coun. tries, especially in Derbyshire, and which are universally thrown away, may, perhaps, be nothing but different kinds of spar, and * Plat ina, rcgulus of cobalt, and nickel. •f Zinc is a metallic sub-,tancr of the colour of lead ; when unit : thus, the conductor of an electrical machine will contain very nearly or quilt- as much electricity if hollow as if solid. If two spheres be united by a cylindrical conducting substance, of small dimensions, there will be an equilibrium, when the actions of the redundant fluid in the spheres, on the whole fluid in the cylinder, are equal ; that is, when both the spheres have their surfaces electrified in an equal degree : but if the length of the cylinder is considerable, the fluid within it can only remain at rest when the quantities of redundant fluid are nearly equal m both spheres, and consequently when the density is greater in the smaller. And, for a similar reason, in bodies of irregular forms, the fluid is always most accumulated in the smallest parts; and when a conducting substance is pointed, the fluid becomes so dense at its extremity, as easily to overcome the forces which tend to retain it in its situation. In this distribution we find a very charisteristie difference be. tween the pressure of the electric fluid, and the common hydro. static pressure of liquids, or of simple elastic fluids ; for these rxrrt on every surface, similarly situated, a pressure proportionate to its magnitude ; but the electric fluid exerts a pressure on small niul angular surfaces, greater, in proportion to their magnitudes, than the pressure on larger parts : so that if the electric fluid were in general confined to its situation, by the pressure of the atmo. sphere, that pressure might easily be too weak to oppose its escape from any promr-.ent points. It ('oes not appear, however, that this pressure i> (1 e only cause which prevents the escape of the electric fluid , nor is jr. certain that this fluid can pass through a perfect vacuum, although it has not yet been proved, that a body placed in a vacuum is perfectly insulated. Whatever the resist- ance n.ny be, which prevents the dissipation of electricity, it is always the more easily overcome, as the electrified substance is more pointed, and as the point is more prominent; and even the presence of dust is often unfavourable to the success of eh ctncal experiments, on account of the great number of pointed termina- tions which i( affords. The getu-ral effect of electrified bodies on euch other, if their bulk is small in comparison with their distance, is, that they are mutually repelled when in similar states of electricity, and at. ELECTRICITY IN EQUILIBRIUM. tracted when in dissimilar states. This is a consequence immedi- ately deducible from the mutual attraction of redundant matter, and redundant fluid, aud from the repulsion supposed to exist between any two portions, either of matter or of fluid ; and it may also easily be confirmed by experimental proof. A neutral body, if it were a perfect nonconductor, would not be affected either way by the neighbourhood of an electrified body : for while the whole matter contained in it remains barely saturated with the electric fluid, the attractions and repulsions balance each other. But, in general, a neutral body appears to be attracted by an electrified body, on account of a change of the disposition of the fluid which it contains, upon the approach of a body either posi- tively or negatively electrified. The electrical affection produced in this manner, without any actual transfer of the fluid, is called induced electricity. When a body positively electrified approaches to a neutral body, the redundancy of the fluid expels a portion ef the natural quan- tity from the nearest parts of the neutral body, so that it is accu- mulated at the opposite extremity ; while the matter, which is left deficient, attracts the redundant fluid of the first body, in such a manner as to cause it to be more condensed in the neighbourhood of the second than elsewhere ; and hence the fluid of this body is driven still further off, and all the effects are redoubled. The attraction of the redundant fluid of the electrified body, for the redundant matter of the neutral body, is stronger than its repul- sion for the fluid which has been expelled from it, in proportion as the square of the mean distance of the matter is smaller than that of the mean distance of the fluid : so that in all such cases of induced electricity, an attraction is produced between the bodies concerned. And a similar attraction will happen, under contrary circumstances, when a neutral body and a body negatively electri. lied, approach each other. The state of induced electricity may be illustrated by placing a long conductor at a little distance from an electrified substance, and directed towards it ; and by suspending pith balls, or other light bodies from it, in pairs, at different parts of its length : these will repel each other, from being similarly electrified, at the two ends, which are in contrary states of electricity, while at a certain point towards the middle they will remain at rest, the conductor leing here perfectly neutral. It was from the situation of this c4 24 ELECTRICITY IN EQUILIBRIUM. point that Lord Stanhope first inferred the true law of the electric attractions and repulsions, although Mr. Cavendish had before ^ted (he same law as the most probable supposition. Tlie attraction, thus exerted by an electrified body upon neutral substances, is strong enough, if they are sufficiently light, to over, come their gravitation, and to draw them op from a table at some little distance : upon touching the electrified body, if it is a con. ductor, they receive a quantity of electricity from it, and are again repelled, until they are deprived of th« ir electricity by con. tact with some other substance : which, if sufficiently near to the first, is usually in a contrary state, and therefore renders them still more capable of returning, when they have touched it, to the first substance, in consequence of an increased attraction, assisted also by a new repulsion. This alteration has been applied to the construction of several electrical toys ; a little hammer, for ex. ample, has been made to play between two bells; and this instru. ment has been employed for giving notice of any change of the electrical state of the atmosphere. The repulsion which takes place between two bodies, in a similar state of electricity, is the cause of the currents of air which always accompany the discharge of electricity, whether negative or positive, from pointed sub- stances ; each py an overcharge, and that of a plate of air by a spark, appear to be effects of li<- same kind, although the charge of the jar is princi- pally contained in the glass, while the plate of air is perhaps little concerned in the distribution of the electricity. The actual direction of the electric current has not in any in. stance been fully ascertained, although there are some appearances •which seem to justify the common denominations of positive and negative. Thus, the fracture of a charged j;ir of glass, by spon. taneous explosion, is well defined on the positive, and splintered on the negative side, as might be expected from the passage of a foreign substance from the former side to the latter ; and a candle, held between a positive and a negative ball, although it apparently vibrates between them, is found to heat the negative ball much more than the positive. We cannot, however, place much depend, ance on any circumstance of this kind, for it is doubtful whether any current of the fluid, which we can produce, possesses suffi. cient momentum to carry with it a body of sensible magnitude. It is in fact of little consequence to the theory, whether the terms positive and negative be correctly applied, provided that their sense remain determined ; and that, like positive and negative quantities in mathematics, they be always understood of states •which neutralise each other. The original opinion of Dufay, of the existence of two distinct fluids, a vitreous and a resinous elec- tricity, has at present few advocates, although some have thought such a supposition favoured by the phenomena of the galvanic decomposition of water. When electricity is simply accumulated without motion, it does not appear to have any < fleet, either mechanical, chemical, or physiological, by which its presence can be discovered; the acce. leration of the pulse, and the advancement of the growth of plants, which have been sometimes attributed to it, have not been con- firmed by the most accurate experiments. An uninterrupted cur- rent of electricity, through a perfect conductor, would perhaps be also in every respect imperceptible, since the best conductors appear to be the least affected by it. Thus, if we place our hand on the conductor of an electrical machine, the electricity will pass off continually through the body, without exciting any sensation. A constant stream of galvanic electricity, passing through an iron ELECTRICITY IN MOTION. 29 inre, is, however, capable of exciting a considerable degree of heat ; and if it be transmitted through the hands of the operator, it will produce a slight numbness, although in general some inter, ruption of the current is necessary, in order to furnish an accu. mulation sufficient to produce sensible effects ; and such an inter* ruption may even increase the effect of a single spark or shock ; thus, gunpowder is more readily fired by the discharge of a battery passing through an interrupted circuit, than through a series of perfect conductors. The most common effect of the motion of the electric fluid is the production of li^ht. Light is probably never occasioned by the passage of the fluid through a perfect conductor; for when the dischar.e of a large battery renders a small wire luminous, the fluid is not wholly confined to the wire, but overflows a little into the neighbouring space. There is always an appearance of light whenever the path of the fluid is interrupted by an imperfect con. ductor ; nor is the apparent contact of conducting substances suffi- cient to prevent it, unless they are held together by a considerable force ; thus, a chain, conveying a spark or shock, appears lumi- nous at each link, and the rapidity of the motion is so great, that we can never observe any difference in the times of the appearance of the light in its different parts ; so that a series of luminous points, formed by the passage of the electric fluid, between a string of conducting bodies, represents at once a brilliant delinea- tion of the whole figure in which they are arranged. A. lump of sugar, a piece of wood, or an egg, may easily be made luminous in this manner ; and many substances, by means of their proper, ties as solar phosphori, retain for some seconds the luminous appearance thus acquired. Even water is so imperfect a conductor, that a strong shock may be seen in its passage through it ; and when the air is sufficiently moistened or rarefied to become a conductor, the track of the fluid through it is indicated by streams of li^ht, which are perhaps derived from a series of minute sparks passing between the particles of water, or of rarefied air. When the air is extremely rare, the light is greenish ; as it becomes more dense, the light becomes blue, and then violet, until it no longer con- ducts. The appearance of the electrical light of a point enables us to distinguish the nature of the electricity with which it is charged ; a pencil of light, streaming from the point, indicating that its electricity is positive ; while a luminous star, with few SO ELECTRICITY IN MOTION. diverging rays, shows that k is negative. The sparks, exhibited by small balls, differently Htctrifi< -d, have also similar varieties irt their forms, according to the nature of their charges. The production of heat by electricity frequently accompai that of light, and appears to depend in some measure on the circumstances. A fine wire may be fused and dissipted by the discharge of a battery; and without being perfectly melted, it may sometimes be shortened or lengthened, accordingly .1- it i loose or stretched during the experiment. The more readily a metal conducts, the shorter is the portion of it which the same shock can destroy ; and it has sometimes been found, that a double charge of a battery has been capable of melting a quadruple length of wire of the same kind. The mechanical effects of electricity are probably in many cases the consequences of the rarefaction produced by the heat which is excited ; thus, the explosion attending the transmission of a shock or spark through the air, may easily be supposed to be derived from the expansion caused by heat ; and the destruction of a glass tube, which contains a fluid in a capillary bore, when a spark is caused to pass through it, is the natural consequence of the con. version of some particles of the fluid into vapour. But when a glass jar is perforated, this rarefaction cannot be supposed to be adequate to the effect. It is remarkable that such a perforation may be made by a very moderate discharge, when the glass is in contact with oil or with sealing wax ; and no sufficient explanation of this circumstance has yet been given. A strong current ol electricity, or a succession of shocks or sparks, transmitted through a substance, by means of fine wires, is capable of producing many chemical combinations and decom- positions, some of which may be attributed merely to the heat which it occasions, but others are wholly different. Of these the moat remarkable is the production of oxygen and hydrogen gas from common water, which are usually extricated at once, in such quantities, as, when again combined, will reproduce the water which lias disappeared; but in some cases the oxygen appears to be disengaged most copiously at the positive wire, and the hydro- gen at the negative. When the spark is received by the tongue, it has generally a subacid taste ; and an explosion of any kind is usually accompa. nied by a smell somewhat like that of sulphur, or rather of fired ELECTRICITY IN MOTION. 31 gunpowder. The peculiar sensation which the electric fluid occa- sions in the human frame, appears in general to be derived from the spasmodic contractions of the muscles through which it passes ; although in some cases it produces pain of a different kind ; thus, the spark of a conductor occasions a disagreeable sensation in the skin, and when an excoriated surface is placed in the galvanic cur- rent, a sense of smarting, mixed with burning, is experienced. Sometimes the effect of a shock is felt most powerfully at the joints, on account of the difficulty which the fluid finds in passing the articulating surfaces which form the cavity of the joints. The sudden death of an animal, in consequence of a violent shock, is probably owing to the immediate exhaustion of the whole energy of the nervous system. It is remarkable that a very minute tre- mor, communicated to the most elastic parts of the body, in par- ticular to the chest, produces an agitation of the nerves, which is not wholly unlike the effect of a weak electricity. The principal modes in which the electric equilibrium is prima- rily destroyed are, simple contact, friction, a change of the form of aggregation, and chemical combinations and decompositions. The electricity produced by the simple contact of any t\vo sub- stances is extremely weak, and can only be detected by very de- licate experiments : in general it appears that the substance, which conducts the more readily, acquires a slight degree of negativr conductor becomes positive. At the instant in which the friction is applied, the capacities or attractions of the bodies for electricity- appear to be altered, and a greater or less quantity is required for saturating them ; and upon the cessation of the temporary change, this redundancy or deficiency is rendered sensible. When two substances of the same kind are rubbed together, the smaller or the rougher becomes negatively electrified; perhaps because the smaller surface is more heated, in consequence of its under* going more friction than an equal portion of the larger, and hence becomes a better conductor ; and because the rougher in itself is a better conductor than the smoother, and may possibly have its conducting powers increased by the greater agitation of its parts which the friction produces. The back of a live cat becomes S<2 KLLCTKICITY IN MOTION. positively electrified, with whatever substance it is rubbed ; glass is positive in most cases, but not when rubbed with mercury in a vacuum, although sealing wax, which is generally negative, is rendered positive by immersion in a trough of mercury. When a white and a black silk stocking are rubbed together, the while stocking acquires positive electricity, and the black negative; perhaps because the black dye renders the silk both rougher, and a better conductor. Those substanc-es, which have very little conducting power, are sometimes called electrics, since they are capable of exhibiting readily the electricity which friction excites on their surfaces, where it remains accumulated, so that it may be collected into a conductor; while the surfaces of such substances as have greater conducting powers, do not so readily imbibe the fluid from others with which they aro rubbed, since they may be supplied from the internal parts of the substances themselves, when thtir altered capacity requires it; thus, glass, when heated to 110° of Fahren- heit, can with difficulty be excited, becoming an imperfect COD. ductor: but a thin plate of a conducting substance, when in. ^ulated, may be excited almost as easily as au electric, commonly so called. Vapours are generally in a negative state, but if they rise from metallic substances, or even from some kinds of heated glass, the effect is uncertain, probably on account of some chemical actions which interfere with it. Sulphur becomes electrical in cooling, and wax candles are said to be sometimes found in a state so elec- trical, wheji they are taken out of their moulds, as to attract the particles of dust which are floating near them. The tourmalin, and several other crystallized stones, become electrical when heated or cooled, and it is found that the disposition assumed by the fluid, bears a certain relation to the direction in which the stone transmits the light most readily ; some parts of the crystal being rendered always positively and others negatively electrical, by an increase of temperature. The most remarkable of the phenomena attending the excitation of electricity of chemical changes, are those which have lately received the appellation of galvanic. Some of the effects which have been considered as belonging to galvanism are probably de- riv. d from the electrical powers of the animal body, and the rest hare been referred by Mr. Volta, and many other philosophers ELECTRICITY IN MOTION. §3 on the continent, to the mere mechanical actions of bodies pos- sessed of different properties with regard to electricity. Thus, they have supposed thut when a circulation of the electric fluid is produced through a long series of substances in a certain direc. tion, the differences of their attractions and of their conducting powers, which must remain the same throughout the process, keep up this perpetual motion, in defiance of the general laws of me, chanical forces. In this country it has been generally maintained, that no explanation founded on such principles could be admis. sible, even if it were in all other respects sufficient and satisfac. tory, which the mechanical theory of galvanism certainly is not. The phenomena of galvanism appear to be principally derived from an inequality in the distribution of the electric fluid, origi- nating from chemical changes, and maintained by means of the resistance opposed to its motion, by a continued alteration of substances of different kinds, which furnishes a much stronger obstacle to its transmission than any of those substances alone would have done. The substances employed must neither consist wholly of solids nor of fluids, and they must be of three different kinds, possessed of different powers of conducting electricity ; but whether the difference of their conducting powers is of any other consequence than as it accompanies different chemical pro. perties, is hitherto undetermined. Of these three substances, two must possess a power of acting mutually on each other, while the other appears to serve principally for making a separate connexion between them : and this action may be of two kinds, or perhaps more ; the one is oxidation, or the combination of a metal or an inflammable substance with a portion of oxygen derived from water or from acid ; the other sulphuration, or a combination with the sulphur contained in a solution of an alkaline sulphuret. We may represent the effects of all galvanic combinations, by considering the oxidation as producing positive electricity in the acting liquid, and the sulphuration as producing negative electri- city, and by imagining that this electricity is always communicated to the best conductor of the other substances concerned, so as to produce a circulation in the direction thus determined. For ex- ample, when two wires of zinc and silver, touching each other, are separately immersed in an acid, the acid, becoming positively electrical, imparts its electricity to the silver, and hence it flows back into the zinc : when the ends of a piece of charcoal ar« vor<. vr. D 34 ELECTRICITY IN MOTION. dipped into water and into an acid, connected together by a small tube, the acid, becoming positive, sends its superfluous fluid through the charcoal into the water; and if a wire of copper be dipped into water and a solution of alkaline sulphuret, connected •with each other, the sulphuret, becoming negative, will draw the fluid from the copper on which it acts : and in all these cases the direction of the current is truly determined, as it may be shewn by composing a battery of a number of alterations of this kind, and either examining the state of its different parts by electrical tests, or connecting wires with its extremities, which, when im- mersed into a portion of water, will exhibit the production of oxygen gas where they emit the electric fluid, and of hydrogen where they receive it. These processes of oxidation and of sul- phuration may be opposed to each other, or they may be com. bined in various ways, the sum or difference of the separate actions being obtained by their union ; thus it usually happens, that both the metals employed are oxidable in some degree, and the oxida. tion, which takes place at the surface of the better conductor, tends to impede the whole effect, perhaps by impeding the passage of the fluid through the surface. The most oxidable of the metals, and probably the wont conductor, is zinc ; the next is iron ; then. come tin, lead copper, silver, gold, and platina. In the same manner as a wire charged with positive electricity causes an extrication of oxygen gas, so the supply of electricity through the more conducting metal promotes the oxidation of the zinc of a galvanic battery ; and the effect of this circulation may be readily exhibited, by fixing a wire of zinc and another of silver or platina, in an acid, while one end of each is loose, and may be brought together or separated at pleasure : for at the moment that the contact takes place, a stream of bubbles rising from the platina, and a white cloud of oxid falling from the zinc, indicate both the circulation of the fluid and the increase of the chemical action. But when, on the other hand, a plate of zinc is mad* negative by the action of an acid on the greater part of its surface, a detached drop of water has less effect on it, than in the natural state: while a plate of iron, which touches the zinc, and forms a part of the circle with it, is very readily oxidated at a distant point: such a plate must therefore be considered, with regard to this effect, as being made positive by the electricity which it re- ceives from the acid or the water ; unless something like a com* ELECTRICITY IN MOTION. 85 pensation be supposed to take place, from the effects of induced electricity. Instead of the extrication of hydrogen, the same causes will sometimes occasion a deposition of metal which has been dissolred, will prevent the solution of a metal which would otherwise have been corroded, or produce some effects which ap- pear to indicate the presence of an alkali, either volatile or fixed. All these operations may, however, be very much impeded by the interposition of any considerable length of water, or of any other imperfect conductor. It is obvious, that since the current of electricity, produced by a galvanic circle, facilitates those actions from which its powers are derived, the effect of a double series must be more than twice as great as that of a single one : and hence arises the activity of the pile of Volta, the discovery of which forms the most important era in the history of this department of natural knowledge. The intensity of the electrical charge, and the chemical and physiolo- gical effects of a pile or battery, seem to depend principally on the number of alterations of substances; the light and heat more on the joint magnitude of the surfaces employed. In common electricity, the greatest heat appears to be occasioned by a long continuation of a slow motion of the fluid ; and this is perhaps best furnished in galvanism by a surface of large extent, while some other effects may very naturally be expected to depend on the intensity of the charge, independently of the quantity of charged surface. It may easily be imagined, that the tension of the fluid must be nearly proportionate to the number of surfaces, imper- fectly conducting, which are interposed between the ends of a piU or battery, the density of the fluid becoming greater and greater by a limited quantity at each step : and it is easily understood, that any point of the pile may be rendered neutral, by a connec- tion with the earth, while those parts, which are above or below it, will still preserve their relations unaltered with respect to each other: the opposite extremities being, like the opposite surface of a charged jar, in contrary states, and a partial discharge being produced, as often as they are connected by a conducting sub- stance. The various forms in which the piles or troughs are con. structed, are of little consequence to the theory of their operation: the most convenient are the varnished troughs, in which plates of silvered zinc are arranged side by side, with intervening spaces for the reception of water, or of an acid. .,('» 'MCITY IX MOTION. It is unquestionable torpedo, the gymnotus electrii and .M>Hie other iislus, have organs appropriated to the excitation of electricity, and that they have a power of communicating this electririt\ at pleasure to conducting substances in their neighbour- hood. These organs somewhat resemble in their appearance the plates of the galvanic pile, although we know nothing of the im- mediate arrangement from which their electrical properties are derived ; l;ut the effect of the shock which they produce, resembles in all respects that of the weak charge of a very large, bat. tery. It has been shewn by the experiments of (Jalvani, Volta, and Aldini, that the nerves and muscles of the human body possess some electrical powers, although they are so much l*-ss concerned in the phenomena which were at first attributed to them by Gal- vani, than he originally supposed, that many philosophers have been inclined to consider the excitation of electricity as always occasioned by the inanimate substances employed, and the spas- modic contractions of the muscles as merely very delicate tests of the influence of foreign electricity on the nerves. Such is the general outline of the principal experiments and con- clusions which the subject of galvanism afforded before Mr. Davy's late ingenious and interesting researches, which have thrown much light, not only on the foundation of the whole of this class of phaenomena, but also on the nature of chemical actions and affinities in general. Mr. Davy is inclined to infer from his experiments, that all the attractions, which are the causes of chemical combina- tions, depend on the opposite natural electricities of the bodies concerned ; since such bodies are always found by delicate tests, to exhibit, when in contact, marks of different species of elec- tricity ; and their mutual actions may be either augmented or destroyed, by increasing their mutual charges of electricity, or by electrifying them in a contrary way. Thus an acid and a metal are found to be negatively and positively electrical with respect to each other ; and by further electrifying the acid negatively, and the metal positively, their combination is accelerated ; but when the acid is positively electrified, or the metal positively, they have no effect whatever on each other. The acid is also attracted, as a negative body, by another positively electrified, and the metal by a body negatively electrified, so that a metallic salt may be decomposed in the circuit of Volta, the positive point attract- ing the acid, and the negative point the metal : and these attrac- ELECTRICITY IN MOTION. S? lions are so strong, as to carry the partidos of the respective bodies through an intervening medium, which is in a fluid ^tafp, or even through a moist solid; nor are they intercepted in thoir passage by substances, which in other cases, have the strongest elective attractions for them. Alkali, sulphur, and alkaline sul- phurets, are positive with respect to destined to be the subject of his experiment* ; and to their legs he faMen«-d wires which reached the floor. These cxpe- rimcnts were not confined to frogs alone. Di fie rent animals, both of cold and warm Wood, were subjected to them; and in all ot them considerable movements were excited whenever it lightened. These preceded thunder, and corresponded with its intensity and re. petition ; and even when no lightning appeared, the movements took place when any stormy cloud passed over the apparatus. That all these appearances were produced by the electric fluid was ob- vious. Having soon after this suspended some frogs from the iron pali- sades which surrounded his garden, by means of metallic hooks fixed in the spines of their backs, he observed that their muscles contracted frequently and involuntarily, as if from a shock of elec- tricity. Not doubting that the contractions depended on the elec- tric fluid, he at first suspected that they were connected with changes in the state of the atmosphere. He soon found, however, that this was not the case; and having varied, in many different ways, the circumstances in which the frogs were placed, he at length disco, vered that he could produce the movements at pleasure by touching the animals with two different metals, which at the same time, touched one another either immediately or by the intervention of some other substance capable of conducting electricity. , All the experiments that have been made may be reduced to the / following, which will give the otherwise uninformed reader a pre- / else notion of the subject. / Lay bare about an inch of a great nerve, h -ading to any limb or / nuiM-.Ie. Let that end of the bared part which is farthest from the I limb be in close contact with a hit of zinc. Touch the xinc with a o/ bit of silver, while another part of the silver touches, either the ' naked nerve, if not dry, or, whether it be dry or not, the limb or muscle to which it leads. Violent contractions are produced in the limb or muscle, but not in any muscle on the other side of the zinc. Or, touch the bared uervc with a piece of zinc, and touch, with a piece of MJ\er, either the bared nerve, or the limb; no convulsion i- ohH-rved, till the /inc and silver are also made to touch each other* GALVANIC ELECTRICITY. 45 A tact so new, illustrated with so many experiments and much ingenious reasoning, which professor Galvani soon published, could not fail to attract the attention of physiologists all over Europe; and the result of a vast number of experiments, equally cruel and surprising, has been from time to time laid before the public by Valli, Fowler, Monro, Volta, Hmnbolt, and others. Frogs, unhappily for themselves, have been found the most con. venient subjects for these experiments, as they retain their muscular irritability and susceptibility of the galvanic influence very long. Many hours after they have been decapitated, or have had their brain and spinal marrow destroyed, strong convulsions can be pro. duced in them by the application of the metals. A leg separated from the body will often continue capable of excitement for several days. Nay, very distinct movements have been produced in frogs pretty far advanced in the process of putrefaction. Ditfcrent kinds of fishes, and many other animals, both of cold and warm blood, have been subjected to similar experiments, and have exhibited the same phenomena ; but the warm blooded animals lose their sus. ceptibility of galvanism, as of every other stimulus, very soon afler death. / Almost any two metals will produce the movements; but, it is j believed, the most powerful are the fbllowing, in the order which °^ they are here placed: 1. Zinc; 2. Tin; 3. Lead; in conjunction with 1. Gold: 2. Silver; 3. Molybdena; 4. Steel; 5. Copper. \Upon this point, however, authors are not perfectly agreed. The process by which these singular phenomena are produced consists in effecting, by the use of the exciting apparatus, a mutual communication between any two points of contact, more or less dis. tant from one another, in a system of nervous and muscular organs. The sphere of this mutual communication may be regarded as a complete circle, divided into two parts. That part of it which con- sists of the organs of the animal under the experiment has been called the animal arc ; that which is formed by the galvanic instru- ments has been called the excitatory arc. The latter usually con- sists of more pieces than one ; of which some are named stays, braces, &c. others communicators, from their respective uses. Besides the effects thus produced on the muscles, the impressions made on the organs of sense are equally remarkable. And as the experiments illustrating them may be easily repeated, we shall spe- cify some of the most interesting. For instance, if a thiu plate of •l6 GALVANIC ELECTRICITY. /inc be placed on the upper surface of the tongue, and both mefals after a short space of time be brought into contact, a peculiar sensation, or taste, will be perceived at the moment when the mutual touch happens. If the silver be put beneath, and the zinc upon the tongue, the same sensation will arise, but in a weaker de- gree, resembling diluted ammoniac, from which it in all probability derives its origin. If a silver probe be introduced as far as convenient into one of the nostrils, and then be brought into contact with a piece of zinc pinned on the tongue, a sensation not onlike a strong flash of light will be produced in the corresponding eye, at the instant of contact. A similar perception will result, both at the moment of contact and that of separation, if one of the metals be applied as high as possible between the gums and upper lip, and the other in a similar situation with the under lip, or even under the tongue. Lastly, when a probe or rod of zinc, and another of silver, are introduced as far back as possible into the roof of the mouth, the irritations produced by bringing the external ends into contact, are very power, ful ; and that caused by the zinc is similar in taste to the sensation arising from its application to the tongue. No method has hitherto been discovered of applying the galvanic influence in such a manner as to affect the senses of smell, hearing, and touch ; though several eminent philosophers have carefully in. vestigated the subject. Nor are the causes of these phacJiomena clearly ascertained ; Galvani and many of his followers supposing them to depend on ihe electric fluid, while others attribute them to the influence of various physical agents. ^JWr. Crceve, surgeon in Wurtzburg, had an opportunity of ob- ( serving the irritation on the leg of a boy, which had been amputated \ far above tie knee in the hospital of that city. Immediately after / the amputation, Mr. Creeve laid bare the crural nerve (kiekehlner- \ ven), and surrounded it with a slip of tinfoil. He touched at once the tinfoil and the nerve with a French crown-piece. In that infant the most violent convulsions took place in the leg both above and below the knee. The remainder of the thigh bone bent with force toward the calf; the foot was more bent than extended. All these motions were made with much force and rapidity. None were pro, duced when the tinfoil was taken away, or when a steel pincer was used in place of a piece of silver, or when the tin or silver was co- vered with blood ; but they were renewed when these obstacle* GALVANIC ELECTRICITY. 47 were removed. These phaenomena continued till 38 minutes after the amputation, when the limb became cold. The principle, however, upon which the electric pouer acted was misunderstood; nor were any means as yet devised by which the new power could be accumulated to any definite extent, or made ap. plicable to any useful purposes. Galvani explained the phenomenon by conceiving the muscles to resemble a charged Leyden phial, having electricity accumulated in the inside, while the outside was minus. The nerves he conceived to be connected with the inside: when it was united with the out. side by conductors, the surplus electricity was discharged, and hence the motions of the limb. M. Volta, professor of natural philosophy at Como in the Mila. nese, soon discovered, however, that the convulsions were produced by a different operation of the electric principle; in reality by merely touching two different parts of the same nerve by two different me. tals, and thus making a circuit of the three substances, of which the part of the nerve selected for the purpose formed the middle : and pursuing this simple but beautiful law, he soon afterwards perceived that the two distinct metals alone had an action upon each other when brought into contact, but that the action was considerably in. creased by the interposition of a third substance of a different na. ture. The hypothesis of Galvani was hereby completely destroyed, and a foundation laid for that wonderful electric column which has been called the galvanic, or more correctly the voltaic pile, which, by the simple means of multiplying plates of two different kinds of metal, with an interposition of a plate of some other substance be- tween each, produces such an accumulation of electric power; and, when the force of the opposite ends is brought into approximation by means of a flexible wire, or other conductor, attached to each end, such an exertion of this power as to become one of the most, if not altogether the most energic agents in chemistry. And we now advance to the second and most important stage of this new branch of natural science; for which the world is entirely indebted to the penetrating genius of M. Volta, and the curious facts and phenomena of which have hence been universally denominated voltaism. M. Volta commenced his experiments in 1793, and it was seven years before he rendered his pile sufficiently satisfactory and perfect to usher its description and powers before the public. This, how- 48 GALVANIC I'.LKCTKICITY. ever, he accomplished in 1800; at which time lie communicated a particular account of it to tin- Ko\al Society, through the medium of Sir Joseph Banks, \\lio published this valuable paper in the latter part of their Transactions tor that year. His apparatus, as there described, n-iiM>ts of a number of copper or silver plates (which last are preferable), together with an equal number of plates come of tin, or still better of zinc, and a similar number of pieces of card, leather, or woollen cloth, the last of which substances appears to be the most suitable. These last should be well soaked in water -aturated with common salt, muriat of ammonia, or more effect ualiy with nitre. The silver or copper may be pieces of money, and the plates of zinc may be cast of the same size. A pile is then to be formed, by placing a piece of silver on a corresponding one of zinc, and on them a piece of wet cloth or card : which is to be repeated alternately, till the number required be arranged in regular succes- sion. But, as the pieces are apt to tumble down, if their numbers be considerable, unless properly secured, it will be advisable to sup- port thorn by means of three rods of glass, or baked wood, fixed into a flat wooden pedestal, and touching the pieces of metal at three equi.distant points. Upon these rods may be made to slide a small circular piece of wood, perforated with three holes, which will serve to keep the top of the pile firm, and the different layers in close contact. The moistened pieces should likewise be som. - what smaller than those of metal, and gently squeezed before they are applied, to prevent the superfluous moisture from insinuating itself between the pieces of metal. Thus constructed, the apparatus will afford a perpetual current of the eleclric fluid, or voltaic in- fluence, through any conductor that communicates between the uppermost and lowest plate; and, if one hand be applied to the latter, and the other to the highest metal, a shock will be perceived, which may be repeated as often as the contact is renew ed. This fehock greatly resembles that given by the torpedo, or gymnotus electricus : and, according to the larger size of the metallic plates, the shock will be proportionably stronger. The intn.MK .if the charge, however, is so slow, that it cannot penetrate the skin ; it will therefore be necessary to wet both hands, and to »ra-p ;J piece of metal in each, in order to produce the desired enVt : it- power may I;. <.<,in.lerably increased, both by an elevation of tempera'ure, and by augmenting the number of pieces that compose the pile. Thus, 20 pieces of each will emit a shock, that is very perceptible GALVANIC ELECTRICITY. 4JJ in the arms ; if 100 be employed, a very severe but tremulous and continued sensation will extend even to the shoulders ; and, it the surface of the skin be broken, the action of the voltaic influence will be uncommonly painful. The sensation of a flash, or shock with this apparatus, does not materially differ from that produced by two simple plates, but it may be effected in various ways, especially if one or both hands be applied in a wet state to the lowest plate of the pile ; or any part of the face be brought in contact with a wire communicating with the top piece. Further, if a wire be held between the teeth, so as to rest upon the tongue, that organ, as well as the lips, will become convulsed, the flash will appear before the eye, and a very pungent taste will be perceived in the mouth. When a metallic wire, having a bit of well-burnt charcoal at its extremity, is made to connect the two extremities of the pile, a spark will be perceived, or the point of the charcoal will become ignited. Various other modes of constructing this apparatus have been adopted, some of which are ranch superior in point of convenience. Oue mode is by soldering the plates of zinc and copper together, and by cementing them into troughs of baked wood, covered with cement in the regular order, so as to form ..uils to be filled with the fluid menstruum, each surface of zinc being opposite to a surface of copper ; and this combination is very simple and easy of application. Another form is that of introducing plates of copper and zinc, fas- tened together by a slip of copper, into a trough of porcelain, con. tainbig a number of cells corresponding to the number of the se. ries. The different series may be introduced separately into the troughs and taken out without the necessity of changing the fluid j or they may be attached to a piece of baked wood (and when the number is not very large) introduced into the cells, or taken out together. Similar polar electrical arrangements to those formed by zinc and copper may be made by various alterations of conducting and im- perfect conducting substances: but for the accumulation of the power, the series must consist of three substances or more, and one, at least, must be a conductor. Silver or copper when brought in contact with a solution of a compound of sulphur and potash, at one extremity, and in contact with water or a solution of nitre acid at the other extremity, some saline solution being between the sul- phuretted and the acid solutions, forms an element of a powerful VOL. vi. E SO GALVANIC ELECTRICITY. combination, which will give shocks when fifty are put together. The other is copper, cloth of the same .size moistened with solution moistened in the solution of the compound of sulphur copper, and so on: the specific gravities of the solutions should be in the order in which they are arranged, to prevent the mixture of the acid and sulphuretted solution ; that is, the heaviest solution should be placed lowest. FOJ these and various other progressive discoveries we are chiefly indebted to Sir Humphry Davy ; as we are altogether for the great discovery respecting the agency of voltaism, which was published in the Philosophical Transactions, in a paper which gained the prize proposed on voltaism by the French Emperor. This discovery may be expressed in the following sentence: " The voltaic energy Ira* the property of decomposing all compound substances (supposing the battery sufficiently powerful) when the constituents range them, selves round the wires, passing from the two extremities of the bat- tery, according to the following law : oxygen and acids arrange themselves round the positive wire ; hydrogen, alkalies, earths, and metals, round the negative wire/' From this very important dis- covery Sir Humphry drew several very plausible inferences. Oxy- gen and acids, since they are attracted towards the positive wire, are naturally negative ; while, on the other hand, hydrogen, alka- lies, and metals, being attracted to the negative wire, are naturally positive. When two substances are chemically combined, they are in different states of electricity ; and the more completely opposite these states, the more intimately they are united. To separate the two constituents of bodies from each other, we have only to bring them to the same electrical state ; and this is the effect which vol. taism produces. Hence, chemical affinity is nothing else than the attraction which exists between bodies in different states of elec. tricity. The decomposition of the fixed alkalies, of the alkaline earths and borucic acid, soon after discovered by the same cele- brated chemist, was the natural consequence of his original disco- very. These, though very striking and important, are not to be compared, in point of value, to his original discovery of the decom. posing power of voltaism, which has made us acquainted with a new energy in nature, and put into our possession a much more efficient chemical a»ent than any with which we were before acquained. This is the discovery which does so much honour to Sir Humphry Davy, and has put him on a level with the small number of indi- GALVANIC ELECTRICITY. 51 vidnals \vlm have been fortunate enough to lay open to the world a new law of nature. It lias been doubted by many persons, whether the voltaic and electrical energy were the same : but thousands of experiments might be offered to prove them to be such. M. de Luc's very sim- ple aerial electroscope, or electrical column, as he calls it, may be adverted to, as sufficient of itself to establish this fact. This co- lumn consists of zinc. plates and Dutch gilt. paper, in regular sue. cession, like the metallic plates of the voltaic pile, the groups being from one thousand to ten thousand. When two of these columns are placed horizontally, the one insulated, and the other communi- cating with the ground, each being terminated with a small bell, and a small brass ball is suspended between the two bells by a silken thread, the ball, by the mere influence of the electricity contained in the atmosphere, will chime, by striking alternately from column to column, and consequently from bell to bell, sometimes more or less rapidly, and sometimes more or less loudly, and sometimes scarcely at all, according to the state and proportion of the electric aura ; and the instrument, which is a genuine voltaic pile, not only proves the identity of the electric and voltaic power, but may be conveniently employed as a measurer of the electricity which the at- mosphere contains. It should he observed, however, that as there are no fluids known, except such as contain water, that are capable of being made the medium of connexion between the metals, or metal of the voltaic apparatus, the effect in this, and in all similar instances, is resolved by Sir Humphry Davy into some small quan- tity of moisture, or water still existing in the substances employed, which he asserts will not act if each of the substances be made per- fectly dry. The first distinct experiment upon the igniting powers of large voltaic plates was performed by MM. Fourcroy, Vauqueliu, and Thenard ; but a much grander combination for exhibiting the ef- fects of extensive surface was constructed by Mr. Children, and con- sists of a battery of twenty double plates four feet by two; of which the whole surfaces are exposed, in a wooden trough, in cells co- vered with cement, to the action of diluted acids. The most powerful combination, however, that exists, in which numbers of alternations is combined with the extent of surface, is that constructed by subscriptions of a few zealous cultivators and patrons of science, in the laboratory of the Royal Institution. It consists of two hundred instruments, connected together in regular 5t GALVANIC ELECTRICITY. order, each composed of ten double plates, arranged in ce Us of por celani, and rniituinin^ in i;ic!i plate thirty-two square inches; w that the whole number of double plates is 200O, and the whole sur- face 128,000 square inches. This battery when the cells wrre filled with sixty parts of water mixed with one part of nitric acid, and one part of the sulphuric acid, afforded a series of brilliant and impressive effects. When pieces of charcoal about an inch long . and one-sixth of an inch in diameter were brought near each other (within the thirtieth part or fortieth part of an inch), a bright spark was produced, and more than half the volume of the char, coal became ignited to whiteness ; and by withdrawing the points from each other, a constant discharge took place through the heated air, in a space equal at least to four inches, producing a most bril- liant ascending arch of light, broad, and conical in form in the middle. When any substance was introduced into this arch it in. stantly became ignited ; platina melted as readily in it as wax in the flame of a common candle : quartz, the sapphire, magnesia, lime, all entered into fusion; fragments of diamond, and points of char, coal and plumbago, rapidly disappeared, and seemed to evaporate in it, even when the connexion was made in a receiver exhausted by the air-pump ; but there was no evidence of their having previously undergone fusion. When the communication between the points positively and ne- gatively electrified was made in air, rarefied in the receiver of the air-pump, the distance at which the discharge took place increased as the exhaustion was made ; and when the atmosphere in the vessel supported only one.fourth of an inch of mercury in the barometri- cal cage, the sparks passed through a space of nearly half an inch ; and by withdrawing the points from each other, the discharge was made through six or seven inches, producing a most beautiful corus- cation of purple light, the charcoal became intensely ignited, and some plvttina wire attached to it fused with brilliant scintillations, and fell in large globules upon the plate of the pump. All the pliaenotm-na of chemical changes were produced with intense rapi- dity by this combination. When the points of charcoal were brought near each other in nonconducting fluids, such as oils, ether, and oxy muriate compounds, brilliant sparks occurred, and elastic matter was rapidly generated : and such was the intensity of the flectricity, that sparks were produced, even in good imperfect con- ductors, inch as the nitric and sulphuric acids. [Editor. Pantologia. ' CHAP. III. MAGNETISM. 1 HE theory of magetism bears a very strong resemblance to that of electricity, and it must therefore be placed near it in a system of natural philosophy. We have seen the electric fluid not only exert- ing attractions and repulsions, and causing a peculiar distribution of' neighbouring portions of a fluid similar to itself, but also excited in one body, and transferred to another, in such a manner as to be perceptible to the senses, or at least to cause sensible effects, in its passage. The attraction and repulsion, and the peculiar distribu- tion of the neighbouring fluid, are found in the phenomena of mag. netism ; but we do not perceive that there is any actual excitation, or any perceptible transfer of the magnetic fluid from one body to another distinct body; and it has also this striking peculiarity, that, metallic iron is very nearly, if not absolutely, the only substance capable of exhibiting any indications of its presence or activity. For explaining the phenomena of magnetism, we suppose the par. tides of a peculiar fluid to repel each other, and to attract the par. tides of metallic iron with equal forces, diminishing as the square of the distance increases ; and the particles of such iron must also be imagined to repel each other, in a similar manner. Iron and steel, when soft, are conductors of the magnetic fluid, and become less and less pervious to it as their hardness increases. The ground work of this theory is due to Mr. Aepinus, but the forces have been more particularly investigated by Coulomb, and others. There are the same objections to these hypotheses as to those which constitute the theory of electricity, if considered as original and fundamental properties of matter : and it is additionally difficult to imagine, why iron, and iron only, whether apparently magnetic or not, should repel similar particles of iron with a peculiar force, which happens to be precisely a balance to the attraction of the magnetic fluid for iron. This is obviously improbable ; but the hypotheses are still of great utility in assisting us to generalise, and to retain in memory a number of particular facts which would otherwise be insulated. The doctrine of the circulation of streams of the magnetic fluid hue been justly aud universally abandoned -, and some other theories, much more ingenious, and more probable, for instance that of Mr. E 3 54 MAGNETISM. Provost, appear to be too complicated, and too little supported by facts, to require much of our attention. The distinction between conductors and nonconductors is, with re. spect to the electric fluid, irregular and intricate; but in magnetism» the softness or hardness of the iron or steel constitutes the only difference. Heat, as softening iron, must consequently render it a conductor ; even the heat of boiling water affects it, in a certain degree, although it can scarcely be supposed to alter its temper; but the effect of a moderate heat is not so considerable in magnetism as in electricity. A strong degree of heat appears, from the expe- riments of Gilbert, and of Mr. Cavallo, to destroy completely all magnetic action. It is perfectly certain that magnetic effects are produced by quan- tities of iron incapable of being detected either by their weight or by any chemical tests. Mr. Cavallo found that a few particles of steel, adhering to a hone, on which the point of a needle was slightly rubbed, imparted to it magnetic properties ; and Mr. Coulomb has observed, that there are scarcely any bodies in nature which do not exhibit some marks of being subjected to the influence of mag. netism, although its force is always proportional to the quantity of iron which they contain, as far as that quantity can be ascertained; a single grain being sufficient to make 20 pounds of another metal sensibly magnetic. A combination, with a large proportion of oxygen, de- prives iron of the whole or the greater part of its magnetic proper, ties ; finery cinder is still considerably magnetic, but the more per. feet oxids and the salts of iron only in a slight degree ; it is also said thai antimony renders iron incapable of being attracted by the magnet. Nickel, when freed from arsenic and from cobalt, is decidedly magnetic, and the more so as it contains less iron. Some of the older chemists supposed nickel to be a compound metal con- taining iron ; and we may still venture to assume this opinion as a magnetical hypothesis. There is indeed no way of demonstrating that it is impossible for two substances to be so united as to be incapable of separation by the art of the chemist; had nickel been as dense as platina, or as light as cork, we could not have supposed that it contained any considerable quantity of iron, but in fact the specific gravity of these metals is rery nearly the same, and nickel is never found in nature but in the neighbourhood of iron ; we may therefore suspect, with some reason, that the hypothesis of the existence of iron in nickel may be even chemically true. The MAGNETISM. 55 inrora borealis is certainly in some measure a magnetical phenome- non, and if iron were the only substance capable of exhibiting maguetical effects, it would follow that some ferruginous particles must exist in the upper regions of the atmosphere. The light usually attending this magnetical meteor may possibly be derived from electricity, which may be the immediate cause of a change of the distribution of the magnetic fluid, contained in the ferruginous vapours, that are imagined to float in the air. We are still less capable of distinguishing with certainty in magnetism, than in electricity, a positive from a negative state, or a real redundancy of the fluid from a deficiency. The north pole of a magnet may be considered as the part in which the mag. netic fluid is either redundant or deficient, provided that the south pole be understood hi a contrary sense : thus, if the north pole of a magnet be supposed to be positively charged, the south pole must be imagined to be negative ; and in hard iron or steel these poles may be considered as unchangeable. A north pole, therefore, always repels a north pole, and attracts a south pole. And in a neutral piece of soft iron, near to the north pole of a magnet, the fluid becomes so distributed, by induction, as to form a temporary south pole next to the magnet, and the whole piece is of course attracted, from the great proximity of the attracting pole. If the bar is sufficiently soft, and not too long, the remoter end becomes a north pole, and the whole bar a perfect temporary magnet. But when the bar is of hard steel, the state of induction is imperfect, from the resistance opposed to the motion of the fluid ; hence the attraction is less powerful, and an opposite pole is formed, at a certain distance, within the bar ; and beyond this another pole, similar to the first ; the alternation being some- times repeated more than once. The distribution of the fluid within the magnet is also affected by the neighbourhood of a piece of soft iron, the north pole becoming more powerful by the vicinity of the new south pole, and the south pole being consequently strengthened in a certain degree ; so that the attractive power of the whole mag- net is increased by the proximity of the iron. A weak magnet is capable of receiving a temporary induction of a contrary magnetism, from the action of a more powerful one, its north pole becoming a south pole on tite approach of a stronger north pole; but the original south pole still retains its situation at the opposite end, aud restore* £4 56 MAGNETISM. the magnet nearly to its original condition, after the removal of the disturbing cause. The polarity of magnets, or their disposition to assume a certain direction, is of still greater importance than their attractive power. If a small magnet, or simply a soft wire, be poised on a centre, it will arrange itself in such a direction, us will produce an equilibrium of the attractions and repulsions of the poles of a larger magnet ; being a tangent to a certain oval figure, passing through those poles, of which the properties have been calculated by various mathema- ticians. This polarity may easily be imitated by electricity ; a sus- peuded wire being brought near to the ends of a positive and negative conductor, which are placed parallel to each other, as iu Nairne's electrical machine, its position is perfectly similar to that of a needle attracted by a magnet, of which those conductors represent the poles. The same effect is observable in iron filings placed near a magnet, and they adhere to each other in curved lines, by virtue of their in- duced magnetism, the north pole of each particle being attached to the south pole of the particle next it. This arrangement may be seen by placing the filings either on clean mercury, or on any surface that can be agitated ; and it may be imitated by strewing powder on a plate of glass, supported by two balls, which are contrarily electrified. The polarity of a needle may often be observed when it exhibits no sensible attraction or repulsion as a whole ; and this may easily l»e understood by considering that when one end of a needle is re- pelled from a given point, and the other is attracted towards it, the two forces, if equal, will tend to turn it round its centre, but will wholly destroy each other's effects with respect to any progressive motion of the whole needle. Thus, when the end of a magnet is placed under a surface on which iron filings are spread, and the sur- face is shaken, so as to leave the particles fur a moment in the air, they are not drawn sensibly towards the magnet, but their ends, which are nearest to the point over the magnet, are turned a little downwards, so that they strike the paper further and further from the magnet, and then tall outwards, as if they were repelled by it. The ni.igi.i-t-, \\hicli we have hitherto considered, are sut h as have a simple and well determined form ; but the great compound mag. net, which directs the mariner's compass, and which appears to con. .-is»t principally of the metallic and slightly oxidated iron, contained MAONETISM. 07 iii the internal parts of the earth, is probably of a far more intricate structure, and we can only judge of its nature from the various phae. noineoa derived from its influence. The accumulation and the deficiency of the magnetic fluid, which determine the place of the poles of this magnet, are probably in fact considerably diffused, but they may generally be imagined, without much error in the result, to centre in two points, one of them nearer to the north pole of the earth, the other to the south pole. In consequence of their attractions and repulsions, a needle, whether previously magnetic or not, assumes always, if freely poised, the direction necessary for its equilibrium ; which, in various parts of the globe, is variously inclined to tlie meridian and to the horizon. Hence arises the use of the compass in navigation, and in surveying: a needle, which is poised with a liberty of horizontal motion, assum- ing the direction of the magnetic meridian, which for a certain time remains almost invariable for the same place ; and a similar pro- perty is also observable in the dipping needle, which is moveable only in a vertical plane ; for when this plane is placed in the mag. netic meridian, the needle acquires an inclination to the horizon, which varies according to the situation of the place with respect to the magnetic poles. The natural polarity of the needle may be in some measure illus- trated by inclosing an artificial magnet in a globe ; the direction of a small needle, suspended over any part of its surface, being deter- mined by the position of the poles of the magnet, in the same man. ner as the direction of the compass is determined by the magnetical poles of the earth, although with much more regularity. In either case the whole needle is scarcely more or less attracted towards the globe than if the influence of magnetism were removed ; except when the small needle is placed very near to one of the poles of the artificial magnet, or, on the other hand, when the dipping needle is employed in the neighbourhood of some strata of ferruginous sub* stances, which, in particular parts of the earth, interfere materially with the more general effects, and alter the direction of the magnetic meridian. A bar of soft iron, placed in the situation of the dipping needle, acquires from the earth, by induction, a temporary state of magne- tism, which may be reversed at pleasure by reversin» its direction ; but bars of iron which have remained long in or near this direction, assume a permanent polarity ; for iron, even when it has been at 58 MAGNETISM. first quite soft, becomes in time a little harder. A natural magnet is no more than a heavy iron ore, which, in the course of ages, has acquired a strong polarity, from the great primitive magnet. It must have lain in some degree detached, and must possess but little conducting power, in order to have received and to retain its mag- netism. We cannot, from any assumed situation of two or more magnetic poles, calculate the true position of the needle for all places ; and even in the same place, its direction is observed to change in the course of years, according to a law which has never yet been gene- rally determined, although the variation which has been observed, at any one place, since the discovery of the compass, may perhaps be comprehended in some very intricate expressions ; but the less dependence can be placed on any calculations of this kind, as there is reason to think that the change depends rather on chemical than on physical causes. Dr. Halley indeed conjectured that the earth contained a nucleus, or separate sphere, revolving freely withiu it, or rather floating in a fluid contained in the intermediate space, and causing the variation of the magnetic meridian ; and others have attributed the effect to the motions of the celestial bodies : but in either case the changes produced would have been much more regu- lar and universal than those which have been actually observed. Temporary changes of the terrestrial magnetism have certainly been sometimes occasioned by other causes ; such causes are, therefore, most likely to be concerned in the more permanent effects. Thus, the eruption of Mount Hecla was found to derange the position of the needle considerably; the aurora borealis have been observed to cause it-, north pole to move six or seven degrees to the westward of its iiMial position; and a still more remarkable change occurs con- tinuiiliy in the diurnal variation. In these climates the north pole of the needle moves slowly westwards from about eight in the morn- ing till two, and in the evening returns again ; a change which has with great probability been attributed to the temporary elevation of the tempi-ratiin- of the earth, eastwards of the place of observation, where the sun's action takes place at an earlier hour in the morning, and to the diminution of the magnetic attraction in consequence of the heat thus communicated. in winter this variation amounts to about seven minutes, in summer to thirteen or fourteen. Important as the use of the compass is at present to navigation, it would be still more valuable if its declination from the true meri- MAGNETISM. 59 dian were constant for the same place, or even if it varied according to any discoverable law : since it would afford a ready mode of determining the longitude of a place by a comparison of an astro* nomical observation of its latitude with another of the magnitude of the declination. And in some cases it may even now be applied to this purpose, where we have a collection of late and numerous obser- vations. Such observations have from time to time been arranged in charts, furnished with lines indicating the magnitude of the declination or variation at the places through which they pass, beginning from the line of no variation, and proceeding on the opposite sides of this line to show the magnitude of the variation east or west. It is obvious that the intersection of a given parallel of latitude, with the line showing the magnitude of the variation, will indicate the precise situation of the place at which the observa- tions have been made. The line of no variation passed in 167 5 through London, and in 1666 through Paris : its northern extremity appears to have moved continually eastwards, and its southern parts westwards; and it now passes through the middle of Asia. The opposite portion seems to have moved more uniformly westwards ; it now runs from North America to the middle of the South Atlantic. On the European side of these lines, the declination is westerly ; on the South American side, it is easterly. The variation in London has been for several years a little more than 24°. In the West In- dies it changes but slowly ; for instance it was 5° near the island of Barbadoes, from 1700 to 1756. The dip of the north pole of the needle in the neighbourhood of London is 72°. Hence the lower end of a bar standing upright, as a poker, or a lamp-iron, becomes always a north pole, and a tem- porary south pole of a piece of soft iron being uppermost, it is $omewhat more strongly attracted by the north pole of a magnet placed over it, than by its south pole ; the distribution of the fluid in the magnet itself being also a little more favourable to the attrac. tion, while its north pole is downwards. It is obvious that the magnetism of the northern magnetic pole of the earth must resemble that of the south pole of a magnet, since it attracts the north pole ; so that if we considered the nature of the distribution of the fluid rather than its situation in the earth, we should call it a south pole. Although it is impossible to find any places for two, or even for a <>0 MAGNETISM. greater number of magnetic poles, which will correctly explain the direction of the needle in every part of the earth's surface, yet the dip may he determined with tolerable accuracy, from the snj lion of a small magnet placed at the centre of the earth, and directed towards a point in Baffin's Bay, about 75° north latitude, and 70° longitude west of London ; and the variation of the dip is so incon- siderable, that a very slow change of the position of this supposed magnet would probably be sufficient to produce it ; but the opera- tion of such a magnet, according to the general laws of the forces concerned, could not possibly account for the very irregular dispo. sitionof the curves indicating the degree of variation or declination; a general idea of these might perhaps be obtained from the supposi- tion of two magnetic poles situated in a line considerably distant from the centre of the earth ; but this hypothesis is by no means sufficiently accurate to allow us to place any dependence on it. The art of making magnets consists in a proper application of the attractions and repulsions of the magnetic fluid, by means of the different conducting powers of different kinds of iron and steel, to the production and preservation of such a distribution of the fluid in a magnet, as is the best fitted to the exhibition of its peculiar properties. We may begin with any bar of iron that has long stood in a ver- tical position; but it is more common to employ an artificial magnet of greater strength. When one pole of such a magnet touches the end of a bar of hard iron or steel ; that end assumes in some degree the opposite character, and the opposite end the same character : but in drawing the pole along the bar, the first end becomes neutral, and afterwards has the opposite polarity ; while the second end has its force at first a little increased, then becomes neutral, and after- wards is opposite to what it first was. When the operation is re- peated, the effect is at first in some measure destroyed, and it is difficult to understand why the repetition adds materially to the ine- quality of the distribution of the fluid ; but the fact is certain, and the strength of the new magnet is for some time increased at each stroke, until it has acquired all that it is capable of receiving. Seve. ral magnets, made in this manner, may be placed side by side, and each of them being nearly equal in strength to the first, the whole collf( (inn \\ill produce together a much stronger effect ; and in this manner we may obtain from a weak magnet others continually stronger, until we arrive at the greatest degree of polarity of which MAGNETISM. (il the metal is capable. It is, however, more usual to employ the process called the double touch : placing two magnets, witli their opposite poles near to each other, or the opposite poles of a single magnet, bent into the form of a horse.shoe, in contact with the mid. die of the bar ; the opposite actions of these two poles then conspire in their effort to displace the magnetic iluid, and the magnets having been drawn backwards and forwards repeatedly, an equal number of times to and from each end of the bar, with a considerable pres- sure, they are at last withdrawn in the middle, in order to keep the poles at equal distances. Iron filings, or the scoriae from a smith's forge, when finely levi- gated, and formed into a paste with linseed oil, are also capable of being made collectively magnetic. A bar of steel, placed red. hot between two magnets, and suddenly quenched by cold water, be. comes in some degree magnetic, but not so powerfully as it may be rendered by other means. For preserving magnets, it is usual to place their poles in contact with the opposite poles of other magnets, or with pieces of soft iron, which, in consequence of their own in. duced magnetism, tend to favour the accumulation of the magnetic power in a greater quantity than the metal can retain after they are removed. Hence the ancients imagined that the magnet fed on iron. A single magnet may be made of two bars of steel, with their ends pressed into close contact ; and it might be expected that when these bars are separated, or when a common magnet has been divided in the middle, the portions should possess the properties of the re- spective poles only. But in fact the ends which have been in contact are found to acquire the properties of the poles opposite to those of their respective pieces, and a certain point in each piece is neutral, which is at first nearer to the newly formed pole than to the other end, but is removed by degrees to a more central situation. In this case we must suppose, contrarily to the general principles of the theory, that the magnetic fluid has actually escaped by degrees from one of the pieces, and has been received from the atmosphere by the other. There is no reason to imagine any immediate connexion between magnetism and electricity, except that electricity affects the conduct, ing powers of iron or steel for magnetism, in the same manner as heat or agitation. In some cases a blow, an increase of tempera, ture, or a shock of electricity, may expedite a little the acquisitioa MAGNETISM. <»f polarity ; but more commonly any one of these causes in;; the magnetic power. Professor Robinson found, that when a good m.i^net \\as struck for three quarters of an hour, and allowed in the menu time to ring, its efficacy was destroyed ; although the same operation had little effect when I he ringing was impeded : so that the continued exertion of the cohesive and repulsive powers appears to favour the transmission of the magnetic as well as of the electric fluid. The internal agitation, produced in bending a magnetic wire round a cylinder, also destroys its |>olarity, and the operation of a file has the same effect. Mr. Cavallo has found that brass becomes in general much more capable of being attracted when it has been hammered, even between two flints ; and that this property is again diminished by fire: in this case it may be conjectured that hammer- ing increases the conducting power of the iron contained in the brass, and thus renders it more susceptible of magnetic action. Mr. Cavallo also observed that a magnetic needle was more powerfully attracted by iron filings during their solution in acids, especially in the sulphuric acid, than either before or after the operation : others have not always succeeded in the expert, ment ; but there is nothing improbable in the circumstance, and there may have been some actual difference in the results, de. pendent on causes too minute for observation. In subjects so little understood as the theory of magnetism, we are obliged to admit some paradoxical propositions, which are only surprising on account of the imperfect state of our knowledge. Yet, little as we can un- derstand the intimate nature of magnetical actions, they exhibit to us a number of extremely amusing, as well as interesting, pheno- mena; and the principles of crystallization, and even of vital growth and reproduction, are no where so closely imitated, as in the arrangement of the small particles of iron in the neighbourhood of a magnet, and in the production of a multitude of complete magnets, from the influence of a parent of the same kind. [Young's Natural Philosophy. CHAP. IV. AEROSTATION, INCLUDING THE PRINCIPLES, HISTORY, AND MANAGEMENT OF BALLOONS. SECTION I. Principles of Aerostation. 1 HE fundamental principles of this art have been long and gene- rally known, as well as the speculations on the theory of it j but the successful application of them to practice seems to be altoge- ther a modern discovery. These principles chiefly respect the weight or pressure, and elasticity of the air, with its specific gra- vity, and that of the other bodies to be raised or floated in it ; the particular detail of which principles, however, we have not space to enlarge upon. Suffice it therefore, for the present, to observe, that any body which is specifically, or bulk for bulk, lighter than the atmosphere, or air encompassing the earth, will be buoyed up by it, and ascend, like as wood, or a cork, or a blown bladder, ascends in water. And thus the body would continue to ascend to the top of the atmosphere, if the air were every where of the same density as at the surface of the earth. But as the air is compressible and elastic, its density decreases continually in ascending, on ac- count of the diminished pressure of the superincumbent air, at the higher elevations above the earth ; and therefore the body will as- cend only to such a height where the air is of the same specific gravity with itself; where the body will float, and move along with the wind or current of air, which it may meet with at that height. This body then is an aerostatic machine, of whatever form or na- ture it may be. And an air-balloon is a body of this kind, the whole mass of which, including its covering and contents, and the weights annexed to it, is of less weight than the same bulk of air in which it rises. We know of no solid bodies, however, that are light enough thus to ascend and float in the atmosphere ; and therefore recourse must be had to some fluid or aeriform substance. Among these, that which is called inflammable air, the hydrogen gas of the new nomenclature, is the most proper of any that have hitherto been C)4 I'KINCJPLES OF AEROSTATION. discovered. It is very elastic, ami from six to ten or eleven times lighter than common air; and consequently tins compound uill rise in the ItMXWpbere, ami continue to ascend till it attain a height -at which the atmosphere, is of the same specific gravity a* itself; where it will remain or float with the current of air, as long as the inflammable air does not escape through the pores of its co- vering. And this is an inflammable air-balloon. Another way is to make use of common air, rendered lighter by warming it, instead of the inflammable air. Heat, it is well known, rarefies and expands common air, and consequently lessens its specific gravity; and the diminution of its weight is proportional to the heat applied. If therefore the air, inclosed in any kind of a bag or covering, be heated, and consequently dilated, to such a degree, that the excess of the weight of an equal bulk of common air, above the weight of the heated air, be greater than the weight of the covering and its ap- pendages, the whole compound mass will ascend in the atmosphere, till, by the diminished density of the surrounding air, the wholt becomes of the same specific gravity with the air in which it floats ; where it will remain, till, by the cooling and condensation of the included air, it shall gradually contract and descend again, unless the heat is renewed or kept up. And such is a heated air-balloon, otherwise called a Montgolfier, from its inventor. Now it has been discovered, by various experiments, that one degree of heat, accord- ing.to the scale of Fahrenheit's thermometer, expands the air about one five.hundreth pact ; and, therefore, that it will require about 500°, or nearer 484° of heat, to expand the air to just double its bulk : which is a degree of heat far above what it is practicable to give it on such occasions. And, therefore, in this respect, common air heated is much inferior to inflammable air, in point of levity and usefulness for aerostatic machines. Upon such principles then de- pends the construction of the two sorts of air-balloons. But before treating of this branch more particularly, it will be proper to give a short historical account of this late. discovered art. SECTION II. History of Aerostation. VARIOUS schemes for rising in the air, and passing through it, have been devised and attempted, both by the ancients and 'mo- dems, and that upon different principles, and with various success. HISTORY OP AEROSTATION. 65 Of these, some attempts have been upon meclrauical principles, or by virtue of the powers of mechanism : and such are conceived to be the instances related of (he flying pigeon made by Archjtas ; the flying eagle and fly by Regiomontanus, and various others. Again, other projects have been formed tor attaching wings to some part of the body, which were to be moved either by the hands or feet, by the help of mechanical powers ; so that striking the air with them, after the manner of the wings of a bird, the person might raise him- self in the air, and transport himself through it, in imitation of that animal. The romances of almost every nation have recorded in- stances of persons being carried through the air, both by the agency of spirits and mechanical inventions; but till the time of the cele- brated Lord Bacon, no rational principle appears ever to have been thought of by which this might be accomplished. Friar Bacon, in. deed, had written upon the subject; and many had supposed, that, by means of artificial wings, a man might fly as well as a bird : but these opinions were refuted by Borelli in his treatise De Motu Ani. malium, where, from a comparison between the power of the mus- cles which move the wings of a bird, and those which move the arms of a man, he demonstrates that the latter are utterly insufficient to strike the air with such force as to raise him from the ground. In the year l6f2, Bishop Wilkins published his " Discovery of the New World," in which he certainly seems to have conceived the idea of raising bodies into the atmosphere by filling them with rare- fied air. This, however, he did not by any means pursue ; but rested his hopes upon mechanical motions, to be accomplished by human strength, or by springs, &c. which have been proved inca. pable of answering any useful purpose. The Jesuit, Francis Lann, cotemporary with Bishop Wilkins, proposed to exhaust hollow balls of metal of their air, and by that means occasion them to ascend. But though the theory was unexceptionable, the means were certainly insufficient to the end : for a vessel of cupper, made sufficiently thin to float in the atmosphere, would be utterly unable to resist the ex- ternal pressure, which being demonstrated, no attempt was made upon that principle. So that we may reckon nothing to have been particularly concerted towards aerostation, till the experiment of on« Gasman, a Portuguese friar, wlm is reported early in the last century to have launched a paper b-i\: in;«» ilie aii ; \Oitch, however, soon fell, after attaining the height of 1OO feet. Soon aficr Mr. Caveru dish's discotery of the specific gravity of inflammable air, it occurred TOt. VI. V 66 HISTORY OF AEROSTATION. to the ingenious Dr. Black, of Edinburgh, that if a bladder, suffi- ciently light and thin, were filled with this air, it would form a muss lighter than the same bulk of atmospheric air, and rise in it. This thought was suggested in his lectures in 1707 or 1768 ; and he pro. posed, by means of the allantois of a calf, to try the experiment. Other employments, however, prevented the execution of his d»',it»n. The possibility of constructing a vessel, which, when filled with in. flammable air, would ascend in the atmosphere, had occurred also to Mr. Cavallo about the same time ; and to him belongs the honour of having first made experiments on this subject, in the beginning <>t the year 1782, of which an account was read to the Royal Society, on the 20th of June, in that year. He tried bladders; but the thin, nest of these, however scraped and cleaned, were too heavy. In using China-paper, he found that the inflammable air passed through its pores, like water through a sieve ; and having failed of success by blowing this air into a thick solution of gum, thick varnishes, and oil paint, he was under a necessity of being satisfied with soap, balls ; which, being inflated with inflammable air, by dipping the end of a small glass tube, connected with a bladder containing the air, into a thick solution of soap, and gently compressing the blad- der, ascended rapidly in the atmosphere ; and these were the first sort of inflammable air-ballons that were ever made. But while aerostation seemed thus on the point of being made known in Britain, it was all at once announced in France, by two brothers, Stephen and John Moutgolfier, natives of Annonay, and masters of a considerable paper-manufactory there, who had turned tbeir thoughts to this project as early as the middle of the year 1/82. Their idea was to form an artificial cloud, by inclosing smoke in a bag, and making it carry up the covering along with it. In that year, the experiment was made at Avignon with a fine silk bag ; and by applying a burning paper to an aperture at the bottom, the air was rarefied, and the bag ascended to the height of 70 feet. — Va- rious experiments were now tried upon a large scale, which excited the public curiosity very greatly. An immense bag of linen, lined with paper, and containing upwards of 23,000 cubic feet, was found to have a power of lifting about 500 pounds, including its own weight. Burning chopped straw and wool under the aperture of the machine, immediately occasioned it to swell, and afterwards to ascend into the atmosphere. In ten minutes it had risen 6000 feet: and when its force was exhausted, it fell to the ground at the dis- HISTORY OP AEROSTATION. 67 tance of 7668 feet from the place it had left. Soon after this, one of the brothers, invited by the. Academy of Sciences to repeat his experiments at their expense, constructed a large balloon of an elliptical form. In a preliminary experiment, tins machine lifted from the ground eight persons who held it, and would have carried them all off, if more had not quickly come to their assistance. Next day the machine was rilled by the combustion of fifty pounds of straw, and twelve pounds of wool. The machine soon Dwelled, and sustained itself in the air, together with the charge of between 4 and 500 pounds weight. It was designed to repeat tlie experi- ment before the king, at Versailles ; but a violent storm of rain and wind happening to damage the machine, it became necessary to pre- pare a new one ; and such expedition was used that this vat set at liberty, after having been well filled, it was thirty-five pounds lighter than an equal bulk of common air. It remained in the atmosphere only three quarter* of an hour, during which it traversed fifteen miles. Its sudden descent was supposed to have been owing to a rupture tvhich had taken place when it ascended into the higher regions of the atmosphere. The event oi this experiment; aud the aerial HISTORY OF AEROSTATION. 69 voyage made by Messrs. Rosier and Arlandes, naturally suggested the idea of undertaking something of the same kind with a balloon /illed with inflammable air. The machine used on this occasion was tbrnicd of gores of silk, covered with a varnish of caoutchouc, of a spherical figure, and measuring 27i feet in diameter. A net was spread over the upper hemisphere, and fastened to a hoop, which passed round the middle of the balloon. To this a sort of car was suspended a few feet below the lower part of the balloon ; and in order to prevent the bursting of the machine, a valve was placed in it ; by opening of whirh some of the inflammable air might be oc- casionally let out. The car was of basket work, covered with linen, and beautifully ornamented j being eight feet long, four broad, and three and a half deep ; its weight 130 pounds. Great difficulties again occurred in tilling the machine, but these at last being re- moved, the two adventurers took their seats at three quarters after one in the afternoon of the 1st of December, 1783. At the tim« the balloon rose, the thermometer stood at of Fahrenheit, and the barometer at 30-18 inches; and, by means of the power of ascent with which they left the ground, the balloon rose till the mercury fell to 27 inches, from which they calculated their height to be about 60O yards. Throwing out ballast occasionally as they found the machine descending by the escape of some of the inflammable air, they found it practicable to keep at pretty near the same dis- tance from the earth, during rlie rest of their voyage j the quick- silver fluctuating between 27 and 27*65 inches, and the thermo- meter between 53° and 57°, the whole time. They continued in the air an hour and three quarters, and alighted at the distance of twenty-seven miles from Paris ; having suffered no inconvenience during their voyage, nor experienced any contrary currents of air, as had been felt by Messrs. Pilatre and Arlandes. As the balloon still retained a great quantity of inflammable gas, M. Charles de- termined to take another voyage by himself. M. Robert accord- ingly got out of the machine ; which now being 130 pounds lighter, arose with such velocity, that in twenty minutes he was almost 900O feet in the air, and entirely out of sight of terrestrial objects. The globe, which had been rather flaccid, soon began to swell, and the inflammable air escaped in great quantity. He also drew the valve, to prevent the balloon from bursting ; and the inflammable gas, being considerably warmer than the external air, diffused itself all round, aud was felt like a warm atmosphere, lu teu minutes, ff9 70 HISTORY OP AEROSTATION. Imvvcvrr, the thermometer indicated a great variation of tempera- ture : lu.s fiiiner* were benumbed with cold, and he felt a \iolent pain in his right ear and jaw, which he ascrihed to the expansion of tlie air in these organs as well as to the external cold. The beauty of the prospect which he now enjoyed, however, made amends tor these inconveniencies. At his departure the sun was set on the valleys; but the height to which M. Charles was got into the at- mo^phere rendered him again visible, though only for a short time. He saw, for a few seconds, vapours rising from (he valle\s and ri vers. The clouds seemed to ascend from the earth, and collect one upon the other, still preserving their usual form ; only their colour was grey and monotonous, for want of sufficient light in the atmo-phere. By the light of the moon, he perceived that the ma- chine uas turning round with him in the air; and he observed that there were contrary currents which brought him back ayain. He observed also, with surprise, the effects of the wind, and that the streamers of his banners pointed upwards ; which, he says, could not be the effect either of his ascent or descent, as he was moving horizontally at the time. At last, recollecting his promise of re- turning to hi> friends in half an hour, he pulled the valve, and ac. celerated his descent. When within 200 feet of the earth, he threw out two or three pounds of ballast, which rendered the balloon again stationary ; but, in a little, time afterwards, he gently alighted in a field about three miles distance from the place whence he set out ; though, by making allowance for all the turnings and windings of the voyage, he supposes that he had gone through nine miles at least. By the calculations made, it appears that he rose at this time not less than 10,500 feet ; a height somewhat greater than that of Mount /Etna. The subsequent aerial voyages differ so little from that just now related, that any particular description of them seems to be super, fluous. It had occurred to M. Charles, however, in his last flight, that there might be a possibility of directing the machine in the at. mosphere; and this was afterwards attempted by M. Jean-Pierre Blanchard. In one of the aerostatic excursion* of the latter, he irixi - an account of the sensations he felt during his voyage, and which were somewhat different from those of M. Charles; having in one part ot it found the atmosphere very warm, in another very cold ; and having once found himself very hungry, and at another, time almost overcome by a propensity to sleep. The height to HISTORY OF AEROSTATION. 7i which be arose, as measured by mathematical instruments, was thought to be very little less than 10,000 feet; and he remained in the atmosphere an hour and a quarter. Notwithstanding the rapid progress of aerostation in France, it is remarkable that we have no authentic accounts of any experiments of this kind being attempted in other countries. Even in our own island, where all arts and sciences find an indulgent nursery, and many their birth, no aero- static machine was seen before the month of November, 1*83. Va- rious speculations have been made on the reasons of this strange neglect of so novel and brilliant an experiment ; but none seemed to carry any shew of probability, except that it was said to be dis- couraged by the leader of a philosophical society, expressly instituted for the improvement of natural knowledge, for the reason, as was said, that it was a discovery of a neighbouring nation. Be this however as it may, it is a fact that the first aerostatic experiment was exhibited in England, by a foreigner unconnected and unsup- ported. This was a Count Zambeccari, an ingenious Italian, who happened to be in London about that time. He made a balloon of oiled silk, ten feet in diameter, weighing only eleven pounds ; it was gilt, both for ornament, and to render it more impermeable to the inflammable air, with which it was to be filled. The balloon after being publicly shewn for several days in London, was carried to the Artillery. ground, and there bein« filled about three-quarters with inflammable air, and having a direction, inclosed in a tin box, for any person by whom it should afterwards be found, it was launched about one o'clock on the 25th of November, 1783. At half past three it was taken up, near Petworth, in Sussex, forty-eight miles distant from London ; so that it travelled at the rate of near twtiity miles an hour.. Its descent was occasioned by a rent in the silk, which must have been the effect of the rarefaction of the inflamma- ble air when the balloon ascended to a rarer part of the atmosphere. The attempts of M Blanchard to direct his machine through the atmosphere, were repeated in 1784, by Messrs. Morveau and Ber- trand, at Dijon, who raised themselves with an inflammable air. balloon to the height, as it was thought, of 13,000 feet: passing through a space of eighteen miles in an hour and twenty. five mi- nutes. M. Morveau had prepared oars for directing the machine through the air ; but they were damaged by the wind, so that only two remained serviceable ; by working these, however, they were able to produce a sensible i-rl'ecl on the motion of the machine, lu a third aerial voyage performed by M. Blaucbard, he seemed tw r 4 72 HISTORY OF AEROSTATION. produce some effect by the agitation of his uinu'S both in ascend- ing, descending, moving sideways, and even in some MI* linst the wind : however this is supposed, with some probability, to have been a mistake, as, in all his succeeding VON ages, the effects oi hit machinery could not be perceived. Having said thus much with regard to the conducting aerostatic machines through the atmosphere, we shall now relate the attempt* made to lessen their expence, by falling upon some contrivance to ascend without throwing out ballast, and to descend without I- any of the inflammable air. The first attempt of tliis kind \\.n made by the Duke de Chartres; who, on the 15th of July, 1784, ascended with the tvvo brothers, Charles and Robert, from the park of St. Cloud. The balloon was of an oblong form, made to ascend with its longest diameter horizontally, and measured fifty. five feet in length, and twenty-four in breadth. It contained within it a smaller balloon filled with common air ; by blowing into which with a pair of bellows, and thus throwing in a considerable quantity of common air, it was supposed that the machine would become suf- ficiently heavy to descend ; especially as, by the inflation of the inter- nal bag, the inflammable air in the external one would be condensed into a smaller space, and thus become specifically heavier. The voyage, however, was attended with such circumstances as rendered it impossible to know what would have been the event of the scheme. The power of ascent, with which they set out, seems to have been very great ; as in three minutes after parting from the ground, they were lost in the clouds, and involved in such a dense vapour that they could see neither the sky nor the earth. In this situation they seemed to be attacked by a whirlwind, which, besides turning the balloon three times round from right to left, shocked, and beat it so about, that they were rendered incapable of using any of the means proposed for directing their course, and the silk stuff of which the helm had been composed was even torn away. No scene can be conceived more terrible than that in which they were now in- volved. An immense ocean of shapeless clouds rolled one upon another below them, and seemed to prevent any return to the earth, which still continued invisible, while the agitation of the balloon be- came greater every moment. In this extremity they cut the cords \\lnrh held the interior balloon, and of consequence it fell down upon the aperture of the tube that came from the large balloon into the boat, and stopped it up. They were then driven upwards by a gust of wind from below, which carried them to the top of HISTORY OF AEROSTATION. 75 that stormy vapour in which they had beeu involved. They now -aw tlic sun without a cloud; but the heat of his ra\s, with the di- minished density of the atmosphere, had such au eflect on the in. tiammable air, that the balloon seemed every moment ready to burst. To prevent this they introduced a stick through the tube, in order to push away the inner balloon from its aperture ; but the expansion of the inflammable air pushed it so close, that all at- tempts of this kind proved ineffectual. It was now, howevt r, become absolutely necessary to give vent to a very considerable quantity of the inflammable air ; for which purpose the Duke de Chartres him. self bored too holes in the balloon, which tore open for the length of seven or eight feet. On this they descended with great rapidity ; and would have fallen into a lake, had they not hastily thrown out sixty-pounds of ballast, which enabled them just to reach the water's edge. This scheme for raising or lowering aerostatic ma. chines by bags filled with common air being thus rendered dubious, another method was thought of. This was to put a small aeiostatic machine, with rarefied air, under an inflammable air-balloon, but at such a distance that the inflammable air of the latter might be per* fectly out of the reach of the fire used for inflating the former; and thus, by increasing or diminishing the fire in the small machine, the absolute weight of the whole would be considerably diminished or augmented. This scheme was unhappily put in execution by the celebrated M. Pilatre de llo/ier and M. llomaine. Their inflam- mable air-balloon was about thirty-seven feet in diameter, and the power of the rarefied air one was equivalent to about sixty-pounds. They ascended without any accident; but had not been long in the atmosphere when the inflammable air-balloon was seen to swell very considerably, at the same time that the aeronauts were observed, by means of telescopes, very anxious to get down, and buried in pulling the valve and opening the appendages to the balloon, in order to fa- cilitate the escape of as much inflammable air as possible. Shortly after this the machine took tire, at the height of about three quar. lers of a mile from the ground. No explosion was heard; and the silk of the balloon seemed to resist the atmosphere for about a mi- uute, after which it collapsed, and descended along with the two un- fortunate travellers so rapidly, that both of them were killed. 1'i- latre seemed to have beeu dead before he came to the ground ; but M. Romanic was alive when some persons came up to him, though fce expired immediately after. The first aerial voyage in England was performed on the 15lb of 74 HISTORY OF AEROSTATION. September, 1784, by Vincent Lunardi, a native of Italy. His bal- loon \vas made of oiled silk, painted in alternate stripes of blue and red. Its diameter was thirty-three feet. From a net which went over about two-thirds of the balloon descended forty-five cords to a hoop hanging below the balloon, and to which the gallery was at- tached. The balloon had no valve ; and its neck, which t< natrd in the form of a pear, was the aperture through which the in. flammable air was introduced, and through which it might be let out. The air for tilling the balloon was produced from zinc by means of diluted vitriolic acid. Mr. Lunardi departed from the Ar- tillery ground at two. o'clock; and with him wrre a do'.', a rat, and a pigeon. After throwing out some sand to clear the houses, he ascended to a great height. The direction of his motion at first was NVV by W, but as the balloon rose higher it fell into another current of air, which carried it nearly N. About half after three he descend- ed very near the ground and landed the cat, which was almost dead with cold : then rising, he prosecuted his voyage. He ascribes his descent to the action of an oar ; but as he was under a necessity of throwing out ballast in order to re-ascend, his descent was more probably occasioned by the loss of inflammable air. At ten minutes past four he descended on a meadow, near Ware, in Hertfordshire. The only philosophical instrument which he carried with him was ;t thermometer, which, in the course of his voyage, stood as low as 29°; and he observed that the drops of water collected round the balloon were fro/en. The second aerial voyage, in England, was performed by Mr. Blanchard, and Mr. Sheldon, Professor of Anatomy to the Ko>al Academy, being the first Englishman who ascended with an aerostatic machine. They ascended at Chelsea, the 1 6th of October, 1784, at nine minutes past twelve o'clock. Mr. Blanchard having landed Mr. Sheldon, at about fourteen miles from Chelsea, re-ascended alone, and finally landed, near Rumsey, in Hampshire, about >e\ five miles distant from London, having gone nearly at the rate of twenty miles an hour. The wings used on this occasion, it seems, produced no deviation from the direction of the wind. Mr. Blan- chard said, that he a-cendcd .so high a.s to feel a great difficulty of breathing: and that a pigeon, which flew away from the boat, la. boured, for some time, to sustain itself with its wings in the rarefied air, but after wandering a good while returned, aud rested on the c.ide of the boat. HISTORY OP AEROSTATION. 75 On the 41 li of October, Mr. Sadler, an ingenious tradesman, at Oxford, ascended at that place with an inflammable air balloon of his own consi ruction and tilling. And again, on the twelfth of the -ame inontn, he ascended at Oxford, and floated to the distance of fourteen miles, in seventeen minutes, which is at the rate of near Jifty miles an hour. On the 23d of March, count Zambeccari, and Admiral Sir Edward Vermin, ascended at London, and mailed to Horsham, in Sussex, at the distance of thirty-five miles in less than an hour. The voyage proved very dangerous, owing to some of the machinery about the valve being damaged, which obliged them to cut open some part 01 I he balloon \vheu they were about two miles perpendicular height above the earth, the barometer having fallen from 30-4 to 20 -S inches. In descending they passed through a dense cloud, which felt very cold, and covered them with snow. The observations they made were, that the balloon kept perpetually turning round in a vertical axis, sometimes so rapidly as to make each revolution in four or five seconds; that a peculiar noise, like rustling, was heard among the clouds, and that the balloon was greatly agitated in the descent. Perhaps the most daring attempt was that of Mr. Blanchard and Dr. Jeffries across the straits of Dover. Tin's took place on the 7th of January, 1785, being a clear frosty morn. ing, with a wind, barely perceptible, at NNW. The operation of filling the balloon began at ten o'clock, and at three quarters after twelve every thing was ready for their departure. At one o'clock Mr. Blanchard desired the boat to be pushed off, which now stood only two feet distant from that precipice so finely described by Shakspcare, in his tragedy of King Lear. As the balloon was scarcely sufficient to carry two, they were obliged to throw out all their ballast except three bags of ten pounds each ; when they at last rose gently, though making very little way on account of there being so little wind. At a quarter after one o'clock, (he barometer, which on the cliff stood at 29'7 inches, was now fallen to 27'3, and the weather proved fine and warm. They had now a most beautiful prospect of the south coast of England, and were able to count thirty. seven villages upon it. After passing over several vessels, they found that the balloon, at fifty minutes after «>n«-, was descend- ing, on which they threw out a sack and a half of ballast; but as they saw that it still descended, and that with much greater velocity than before, they now threw out all the ballast. This still proving ineffectual, they next threw out a parcel of books they carried along 70 HISTORY OF A EKOSTAT1OX. \vitli them, which made the balloon ascend, when they were about midway betwixt I'rance and Knglaud. At a quarter past two, find, ing themselves again descending, tliey threw away tin- remainder of their books, and, ten minutes after, they had a mo-,t enchanting prospect of the French coast. Still, however, the machine depend- ed; and as they had now no more ballast, tliey were fain to throw away their provisions for eating, the wings of their boat, and every moveable they could easily spare. " We threw away," says Dr. Jeffries, " our only bottle, which in its descent cast out a steam like smoke, with a rushing noise; and when it struck the water, we heard, and felt the shock very perceptibly on our car and balloon." All this proving insufficient to stop the descent of the balloon, they next threw out their anchors and cords, and at last stripped off their clothes, fastening themselves to certain slings, and intending to cut away the boat as their last resource. They had now the satisfac. tion, however, to find that they were rising; and as they passed over the high lands between Cape Blanc and Calais, the machine rose very fast, and carried them to a greater height than they had been at any former part of their voyage. They descended safely among some trees in the forest of Guienues, where there was just opening enough to admit them. In September, 1785, Mr. Baldwin ascended from Chester, in Mr. Luuardi's balloon ; and, after traversing in a variety of direc- tions, he first alighted in the neighbourhood of Frodsham ; then re- ascending and pursuing his excursions, he finally landed at Rixton- moss, twenty-five miles from Chester. Mr. Baldwin, who pub. lished his observations made during the voyage, and taken from minutes, mentions the following curious particulars. The sensation of ascending he compares to a strong pressure from the bottom of the car upwards against the soles of his feet. At the distance of what appeared to him seven miles from the earth, though by the baro- meter scarcely a mile and an half, he had a grand and most enchant, ing view of the city of Chester and its adjacent places below him. The river Dee appeared of a red colour ; the city very diminutive ; and the town entirely blue. The whole appeared a perfect plane, the highest building-, h.mng no apparent height, but reduced all to the same level, and the whole terrestrial prospect appeared like a co- loured map. The perspective appearance of things to him was very remarkable. The lowe-l bed of vapour that first appeared as cloud, was pure white in detached fleeces, increasing as they rose : they HISTORY OF AEROSTATION. 77 presently coalesced, anil formed, as he expresses it, a sea of cotton, tufting here and there by the action of the air in the undisturbed part of the clouds. The whole became an extended white floor of cloud, the upper surface being smooth and even. Above this white floor he observed, at groat and unequal distances, a vast as- semblage of thunder clouds, each parcel consisting of whole acres in the densest form : he compares their form and appearance to the smoke of pieces of ordnance, which had consolidated, as it were, into masses of snow, and penetrated through the upper surface, or white floor of common clouds, there remaining visible and at rest. He endeavours to convey some idea of the scene by a sketch, which represents a circular view he had from the car of the balloon, him- self being over the centre of the view, looking down on the white floor of clouds, and seeing the city of Chester through an opening, which discovered the landscape below, limited by surrounding va. pour to less than two miles in diameter. The breadth of the outer margin defines his apparent height in the balloon (viz. four miles) above the white floor of clouds. The regions in which he was did not feel colder, but rather warmer, than below ; and the sun felt hottest, when the balloon was stationary. The discharge of a cannon, when the balloon was at a considerable height, was distinctly heard ; and another discharge, when he was at the height of about thirty yards, so disturbed him as to oblige him for safety to lay hold firmly of the cords of the balloon. Omitting the relation of Mr. Crosbie's attempt to cross the Irish Channel, and of Major Mony's narrow escape from drowning in the German Ocean*, we proceed to remark that, about the latter end of August, 1785, the longest aerial voyage we have yet heard of was performed by Mr. Blanchard : he ascended at Lisle, accom- panied by the Chevalier de L'Epinard, and travelled 30O miles in the balloon before it descended. On this occasion, as on some former ones, Mr. Blanchard made trial of a parachute, an instru- ment like a large umbrella, invented to break the fall, in case of au accident happening to the balloon : \\itli this machine he dropped a dog from the car soon after his ascension, which descended gently and unhuit. The most celebrated aeronaut of modern times was M. Garnerin, a man of an ardent and ingenious mind, but pro- • \V> have brcn induced to i : tions shewed how much the earth reflected sound ; for all hi^ words were repeated five or six times. He thought at first that it might he governed by some local circumstance, which indeH is very probable with regard to the repetition. He descended .several time* to the same level, at a distance often leagues asunder, where he con- stantly observed the same c ffect. This great vibration of the air was not sensible to distances exceeding 150 or 200 tones It decreased xvith the distance. Having made a number of aerial vo\ a jjes, M.Gar- nerin's mechanical acquaintance with the requisites for insuring sue. cess was confirmed by frequent experience. This gentleman, availing himself of the short interval of peace, visited England in the summer of 1802; and thus excited the attention of the British public to the almost forgotten subject of aerostation. His voyages made in (hi? country are fresh in the memory of every one; and as they were minutely detailed in several of the daily papers and monthly publi- cations, we shall be the more readily excused giving a full account of them here. On June 29th, this aeronaut, accompanied by a mi. litary gentleman (Captain Snowden) rose from Ranelagh, and alighted near Colchester, in less than three quarters of an hour; having, in that short period, travelled full sixty miles ! During this voyage the aeronauts did not appear to move with any unpleasant rapidity, until they began to descend, when tlu-y were much affected by the boisterousness of the wind : their descent was attended with danger, and occupied some minutes. From this voyage, then, it ma\ fairly be concluded, that the wind oftm moves with much greater velocity than is commonly assigned to it : on the day this vo\ was made, the wind was not thought to be more high and boister- ous than it often is, yet it can hardly be doubled that its velocity was more than eighty miles per hour, and this is nearly double the velo. city which is commonly assigned to such winds. The singular experiment of ascending into the atmosphere with an inflammable air-balloon, and of descending with a machine called a parachute, was performed by M. Garnerin on the 21st of Sep- tember, 1 802. He ascended from St. George's Parade, North Audley.street, and descended safe into a field near the Small-pox HISTORY OF AEROSTATION. 7i) Hospital, in Pancras. The balloon was of the usual sort, viz. of oiled Milk, with a net, from which ropes proceeded, which termi- nated in, or were joinied to, a single rope at a few feet below the balloon. To this rope the parachute was fastened in the following manner. The reader may easily form to himself an idea of this pa- rachute, by imagining a large umbrella of canvass of about thirty feet in diameter, but destitute of the ribs and handle. Several ropes of about thirty feet in length, which proceeded from the edge of the parachute, terminated in a common joining, from which basket shorter ropes proceeded, to the extremities of which a circular was fastened, and in this basket M. Garnerin placed himself. Now the single rope, which has been said above to proceed from the balloon, passed through a hole in the centre of the parachute, also through certain tin tubes, which were placed one after the other in the place of the handle or stick of an umbrella, and was lastly fastened to the basket ; so that when the balloon was in the air, by cutting the end of this rope next to the basket, the parachute, with the basket, would be separated from the balloon, and, m fall- ing downwards, would be naturally opened by the resistance of the air. The use of the tin tubes was to let the rope slip off with greater certainty, and to prevent its beiug entangled with any of the other ropes, as also to keep the parachute at a distance from the basket. The balloon began to be filled at about two o'clock. There were thirty-six casks filled with iron filings and diluted sulphuric acid, for the production of the hydrogen gas. These communicated with three other casks or general receivers, to each of which was fixed a tube that emptied itself into the main tube attached to the balloon. At six, the balloon being quite full of gas, and the parachute, &c. being attached to it, M. Garnerin placed himself in the basket, and ascended majestically amidst the acclamations of innumerable spec, tators. The weather was the clearest and pleasantest imaginable ; the wind was gentle and about west by south ; in consequence of which M. Ganierin went in tbe direction of about east by north. In about eight minutes time, the balloon and parachute had ascended to an immense height, and M. Garnerin, in the basket, could scarcely be perceived. While every spectator was contemplating the grand sight before him, M. Garnerin cut the rope, and in an instant he was separated from the balloon, trusting his safety to the parachute. At first, viz. before the parachute opened, he fell with great velocity ; but as soon as the parachute was expanded, which look place a few moments after, the descent was very gentle and gra- 80 CONSTRUCTION OP BALLOONS/ dual. 1 11 this descent a remarkable circumstance\vas observed, namely, that the parachute with the appendage of cords and In^ket, soon ^>e^;^l) to \ibr.iU1 l.ke the pendulum of a clock, and the vibrations •fat, that more than once the parachute, and the basket with M. Gariieriii, seemed to be on the same level, or quite hori- zontal, which appeared extremely dangerous : however, the extent of the vibrations diminished as he came pretty near tin? ground. On coming to the earth, M. Garnerin experienced some pretty strong shocks, and when he came out of the basket, he was much discomposed; but he soon recovered his spirits, and remained with vut any material hurt. SECTION III. Construction of Balloons. THE shape of the balloon is one of the first objects of considera- tion in the construction of this machine. As a sphere admits the greatest capacity under the least surface, the spherical figure or that which approaches nearest to ic, has been generally preferred. How- ever, since bodies of this form oppose a great surface to the air, and consequently a greater obstruction to the action of the oar or wings than those of some other form ; it has been proposed to construct balloons of a conical or oblong figure, and to make them proceed with their narrow end forward. Some have suggested the shape of a fish ; others, that of a bird ; but either the globular, or the e»2[ like shape, is, all things considered, certainly the best which can be adopted. The bag or cover of an inflammable-air balloon is best made of the silk stuff called lustring, varnished orer. But for a Moutgolfier, or heated. air balloon, on account of its great size, linen cloth has been used, lined within or without with paper, and varnished. Small balloons are made either of varnished paper, or simply of paper unvarnished, or of gold beater's skin, or such-like light substances. The best way to make up the whole coating of the balloon, is by different pieces or slips joined lengthways from end to end, like the pieces composing the surface of a geographical '•e, and contained between one meridian and another, or like the slices into which a melon is usually cut, and supposed to be spread flat out. Now the edges of such pieces cannot be exactly described by a pair of compasses, not being circular, but flatter or less rounder than circular arches; but if the slips are sufficiently •arrow, or numerous, they will differ the less from circles, and may CONSTRUCTION OF BALLOONS. 81 be described as such. But more accurately, the breadths of the slip, at the several distances from the point, to the middle, where it is broade-t, are directly as the sines of those distances, radius being the half length of the slip. After providing the necessary quantity of the stuff, and each piece having been properly prepared with the drying oil, let the corresponding edges be sewed together in such a manner as to leave about half or three quarters of an inch of one piece beyond the edge of the other, in order that this may, in a sub- sequent row of stitches, be turned over the latter, and both again sewed down together, by so doing, a considerable degree of strength is given to the whole bag at the seams, and the hazard of the gass escaping doubly prevented. Having gone in this manner through all the seams, the following method of Mr. Blanchard is admirably calculated to render them )et more perfectly air tight. The seam being doubly stitched as above, lay beneath it a piece of brown paper, and also another piece over it on the outside ; upon this lat. ter pass several times a common fire-iron heated just sufficiently to soften the drying oil in the seam ; this done, every interstice will be now closed, and the seam rendered completely air-tight. The neck of the balloon being left a foot in diameter and three in length, and all the seams finished, the bag will be ready to receive the varnish, a single coating of which on the outside is found preferable to the former method of giving an internal as well as external coat. The compositions for varnishing balloons have been variously modified ; but, upon the whole, the most approved appears to be the bird-lime varnish of M. Faujas St. Fond, prepared after Mr. Cavallo's method, as follows : " In order to render linseed oil dry. ing, boil it, with two ounces of sugar of lead and three ounces of litharge for every pint of oil, till they are dissolved, which may be in half an hour. Then put a pound of bird-lime and half a pint of the drying oil into an iron or copper vessel whose capacity should equal about a gallon, and let it boil very gently over a slow charcoal hre till the bird lime ceases to crackle, which will be in about half or three quarters of an hour : then pour upon it two pints and a half more of the drying oil, and let it boil about an hour longer, stirring it frequently with an iron or wooden spatula. As the varnish whilst boiling, and especially when nearly done, swells very much, care should be taken to remove, in those cases, the pot from the tire, and replace it when the varnish subsides ; otherwise it will boil over. Whilst the stuff is boiling the operator should occasionally examine VOL, TI. c 82 CONSTRUCTION OF BALLOONS. whether it has boiled enough } which may be known by observing whether, when rubbed between two knives and then separated from one another, the varnish forms threads between them, as it must then be removed from the fire ; when nearly cool, add about an equal quantity of spirit of turpentine : in using the varnish, the stuff must be stretched and the varnish lukewarm : in twenty.four hours it will be dry." As the elastic resin, known by the name of Indian rubber, has been much extolled for a varnish, the following method of making it, as practised by Mr. Blanchard, may not prove unaccept. able : Dissolve elastic resin, cut small, in five times its weight of rectified essential oil of turpentine, (ethereal spirit of turpentine of the shops), by keeping them some days together ; then boil one ounce of this solution in eight ounces of drying linseed oil for a few minutes ; strain the solution and use it warm. — The car or boat is best made of wicker-work, covered with leather, and painted ; and the proper method of suspending it, is by ropes proceeding from the net which goes over the balloon. The net should be formed to the shape of the balloon, and fall down to the middle of if, with various cords proceeding from it to the circumference of a circle about two feet below the balloon; and from that circle other ropes should go to the edge of the boat. This circle may be made of wood, or of several pieces of slender cane bound together. The meshes of the net may be small at top, against which part of the balloon the inflam- mable air exerts the greatest force ; and increase in size as they recede from the top. With regard to the rarefied-air machines, Mr. Cavallo recom. mends first to soak the cloth in a solution of sal-ammoniac and com- raon size, using one pound of each to every gallon of water ; and when the cloth is quite dry, to paint it over in the inside with some earthy colour, and strong size or glue. When this paint has dried perfectly, it will then be proper to varnish it with oily varnish, which might dry before it could penetrate quite through the cloth. Simple drying linseed oil will answer the purpose as well as any, provided it be not very fluid. If a parachute is required, it should be constructed so as when distended to form but a small segment of a sphere, and not a complete hemisphere ; as the weight of this ma- chine is otherwise considerably increased, without gaining much in the opposing surface. The parachute of M. Garnerin is particularly defective in too great extension of its diameter ; an unnecessary ad- dition to its weight of a lining of paper both withinside and without; CONSTRUCTION OF BALLOONS. 83 the too near approximation of the basket to the body of the para- chute ; and especially in the want of a perpendicular cord passing from the car to the centre of the concave of the umbrella, by the absence of which the velori'y of the descent is certain to be very rapid before the machine becomes at all distended ; whereas, if a cord were thus disposed, the centre of the parachute would be the portion first drawn downwards by the appended weight, and the machine would he almost immediately at its full extension. Having found, by experiment, the diameter, required for insuring safety, the further the basket or car is from the umbrella, the less fear shall we have of an inversion of the whole from violent oscillations ; yet, the longer the space between the car and the head of t!ie machine, the longer will be the space run through in each vibration when once begun, yet by so much the more will they be steadier ; and this ought to be attended to, as when by the violence of the oscilla- tions the car became (in Garnerin'* experiment) on a line with the horizontal axis of the machine (or, in other words, the point of sus- pensatiou,) the force of gravity, or the gravitating power of the weight in the car, on the umbrella, being at that crisis reduced to nothing, the slightest cause might have carried the body of the machine in a lateral direction, reversing the concavity of the um- brella, and M. Garncrin, perhaps, have fallen upon the now convex yet internal portion of the bag, and the whole have descended con- fusedly together. — It now remains to give some account of the method by which aerostatic machines may be tilled ; and here we are able to determine with much greater precision concerning the inflammable-air balloons than the other kind. With regard to these, a primary consideration is, the most effectual and cheap method of procuring the inflammable-air. It will be found that the most ad- vantageous methods are, by applying acids to certain metals ; by exposing animal, vege able, and some mineral substances, in a close vessel to a strong fire j or lastly, by transmitting the vapour of cer- tain fluids through red-hot tubes. For obtaining inflammable-air from pit. coal, asphaltum, amber, &c. &c. Mr. Cavallo recom- mends the following apparatus : let a vessel be made of clay, or rather of iron, in the shape of a Florence flask, somewhat larger, and whose neck is longer and larger. Put the substance to be used into this vessel, so as to fill about four-fifths or less of its cavity. If the substance be of such a nature as to swell much by (lie action of the fire, lute a tube of brass, or first a brass and 84 CONSTRUCTION OP BALLOONS. then a leaden tube, to the neck of the vessel ; and let the end of the tube be so shaped that going into the water it may terminate under a sort of inverted vessel, to the upper aper- ture of which the balloon is adapted. Things thus prepared, if the part of the vessel is put into the fire, and made red. hot, the inflammable air produced will come out of the tube, and passing through the water will at last enter into the balloon. Previous to the operation, as a considerable quantity of common air remains in the inverted vessel, which it is more proper to expel, the vessel should have a stop-cock, through which the common air may be sucked out, and the water ascend as high as the stop.cock. To procure inflammable air by means of steam, Dr. Priestley used a tube of red.hot brass, upon which the steam of water has no eft'ect, and which he rills with the turnings of iron that are separated in the boring of cannon. By this means he obtained an inflammable air, the specific gravity of which is to that of common air as 1 to 13. In this method, not yet indeed reduced to general practice, a tube about throe-quarters of an inch in diameter, and about three feet long, is filled with iron turnings ; then the neck of a retort, or close boiler, is luted to one of its ends, and the worm of a refrigeratory is adapted to its other extremity. The middle part of the tube is then surrounded with burning coals, so as to keep about one foot in length of it red. hot, and a fire is always made under the retort or boiler sufficient to make the water boil with ve- hemence. In this process a considerable quantity of inflammable air comes out of the refrigeratory. It is said that iron yields one half more air by this means than by the action of vitriolic acid. — With regard to the rarefied.air balloons, the method of filling them is by means of a scaffold, the breadth of which is at least two-thirds of the diameter of the machine, and elevated about six or eight feet from the ground. From the middle of it descends a well, rising about two or three feet above it, and reaching to the eround, fur. nished with a door, through which the fire in the well is supplied with fuel. The well should be constructed of brick, and its dia- meter somewhat less than that of the machine. On each side of the scaffold are erected two masts, each of which is fixed by ropes, and has a pulley at the top. The machine is to be placed on the sraf- fold, with its nock round the aperture of the well. The rope pas. sing over tlu- pullvys of tlte two masts, serves to lift the balloon about fifteen feet above the scaffold ; and it is kept steady, and held CONSTRUCTION OF BALLOONS. QJ riown, whilst fillin«, by ropes passing through loops or holes about its equator ; and these ropes may easily be disengaged from the machine, by slipping (hem through the loops when it is able to MIS. tain itself. The proper combustibles, to be lighted in the well, are those which burn quick and clear, rather than such as produce mm h smoke; because it is hot air, and not smoke, that is required. Small wood and straw are very fit for this purpose. As the current of hot air abends, the machine will dilate, and lift itself above the scaffold and gallery which was covered by it. The passengers, fuel, instru- ments, &c. are then placed in the gallery. When the machine makes efforts to ascend, its aperture must be brought, by means of the ropes annexed to it, towards the side of the well a little above the scaffold ; the fire-place is then su*penci«d in* it, the fire lighted in the grate, and the lateral ropes being slipped off, the machine is let go. It has been determined by accurate experiments, that only one. third of the common air can be expelled from these large machines; and there- fore the ascending power of the rarefied air in them can be estimated as only equal to half an ounce avoirdupoise for every cubic foot. The conduct of balloons, when constructed, filled, and actually ascended in the atmosphere, is an object of great importance in the practice of aerostation. The method generally used for elevating or lowering the balloons with rarefied air, has been the increase or diminution of the fire ; and this is entirely at the command of the aeronaut, as long as he has any fuel in the gallery. The inflamma- ble.air balloons have been generally raised or lowered by diminishing their ballast, or by letting out some of the gas through the valve : but the alternate escape of the air in descending, and discharge of the ballast for ascending, will by degrees render the machine inca- pable of floating ; for in the air it is impossible to supply the loss of ballast, and very difficult to supply that of inflammable air. These balloons will also rise or fall by means of the rarefaction or con. densalion of the inclosed air, occasioned by heat and cold, as has been already observed. Wings or oars are the only means of this sort that have been used with any probable success ; and as Mr, Cavallo observes, they seem to be capable of considerable improve, ment, though much is not to be expected from them, when the machine goes at a great rate, it is a matter of surprise, that the various hints for directing balloons appear to lie dormant with their projectors who seem indisposed to make any attempts to carry their plant into execution : thus the inventions of professor •a 86 CONSTRUCTION OF BA LI.OON S. Daniel (Philosophical Magazine, vol. iv.) also ot Martin, and the proposal* for performing the same bv menu's of eagles trained for the purpose ; or by a reversed paradise In retard the direct pro- gress of tlie balloon, whereby less |>o\\er will he necessary to impel it in a lateral direction ; all these plans remain obsolete and tinprac. tNed from the lime of their suggestion. \Vilh respect to the pro. Lability of directing aerostatic machines, we iua\ inter it to be possible, although the methods hereto tried have been inadequate; perhaps because they were not sufficiently powerful ; as, to expect to make so large a body as a balloon to vary from the wind by the impul>ioii of an oar of six or eight feet in length aud one or two in breadth (and that by only endeavouring to draw the car out of ihe perpendicular) is to expect, by means of a boat's oar, to impel a ship of burthen. Oars are doubtless the most likely means to effect this purpose, if they were of dimensions proportionate to the « fleets they are \islied to produce. The addition of sails, were any variation from the wind is desired, will prove injurious till we have attained a method (perhaps only to be accomplished by oars) of keeping the aame point of the balloon continually in a given direction. Yet we doubt not but these also might prove of great service in quick dis- patches, by water j as, for instance, where it is required to pass a fortress or flirt for the succour of a besieged town, or convey dis. patents thereto : a small balloon, of ten or twelve feet diameter, pioMilin \\itli sails to expose a large surface to the wind, being at- tached by a lung rope to- a boat, would outstrip the quickest vessel, and might also b- made to deviate from the course of the wind ; as tlie water would form a counter-resisting medium, the want of which in air balloons occasions the <;imcully in steering them. A sail bal- loon similar to Ihe above might also be advai>tiig««>u-l\ attached to aland carriage; namely, by increasing the capacity of tlie balloon, so that i.s | o«er of ascension being nearly equal to the weight of the appended carriage, the latter would be drawn along l»y the im- pulsion of the wind against the balloon and sails, while the friction over tlie "round, by the small overplus weight, may be reasonably expected to aflord u resistance sutiicirnt to guide the machine, and allow <.f a (U-viat ion in the carriage ot at least eight points from the course of the wind. Indeed Ihe uses of the art of aerostation, even in is pre>ent incomplete state, may be very considerable. Air balloons may sene the purpose of escaping from ships that cannot safely land, from besieged places, and from other circumstances of CONSTRUCTION OF BALLOONS. 8? danger. They also expedite the communication of important events by signals, and serve for exploring from a great elevation adjacent coasts or regions, fleets and armies. Thus, the French ascribe to the elevation of a balloon, and the information obtained in conse- quence of thus recounoitering the army of the enemy, the signal \iotory gained in the battle of Fleurus, in 17Q4. Balloons may like. wise serve to explore and ascertain the nature of the air in the higher regions of the atmosphere. One of the finest experiments made on this point is that of Gay-Lussac ; who, being elevated in a balloon to the height of 6900metres(nearly eight miles) the greatest ever attained by any person, brought some atmospheric air from those regions, which on being analysed, was found to furnish the principles of oxygen, azote, Indrogeu, and carbonic acid gas, in the same proper. tions as at the surface of the earth. Balloons would also enable us to determine the changes in the direction of the winds at different altitudes, and the law of the diminution of heat at different eleva. tions. In fact, the application of these machines to the advance- ment of our knowledge of the various phenomena in meteorology stands prominent, as the, perhaps, only means of maturing our acquaintance with causes )tt known only by their effects. Their use will also be indicated in many urgent cases where other means of conveyance might fall short. At the same time we conclude with remarking, that the hitherto unsuccessful attempts to render aerial navigation of service to mankind, ought to furnish no argument for causing it to be discouraged by men of sense, or prohibited by civil authority. Many arts and sciences from which commercial nations now derive so much benefit were long in rearing to maturity, and were only at length produced for the public good, in consequence of patient investigation and reiterated experiments. — Much useful in. formation on the theory and practice of aerostation may be obtained from Baldwin's Aeropaidia, Cavallo on Aerostation, and Description des Experiences Aerostatiques, par M. Faujas St. Fond. [Pantologia. a 4 I 38 ] CHAP. V. GASS LIGHTS. SECTION I. Introductory Remarks. I. HB term gass or gas (from the German gheist or spirit, whence our own ghost, ghostly, aghast, ghastly) is used in modern che. inistry, to express all those aerial fluids, whether produced by chemical experiments or evolved in natural processes, which are not condensible by the cold of our atmosphere, and which differ from atmospheric air, which is indeed a compound, consisting of three distinct gasses, as we have already observed in a former part of this work. Of these fluids, some are inflammable, others not. Of the for. mer, the chief are hydrogen, and the gass emitted from phosphorus. It is possible, however, that phosphorus itself is a compound of hydrogen and oxygen, with a peculiar base, and consequently, that hydrogen is the inflammable principle in this instance. Be this as it may, phosphorus, concerning which we shall treat presently, is by no means so easily procured as hydrogen, and hence, it is this last which is ordinarily had recourse to, in pro. cesses for the production of light or inflammation from gasseous substances. We have observed in the preceding chapter on AEROSTATION, that the earlier name for hydrogen was inflammable air, a name indeed derived from this very principle of inflammability ; its mo. dern name was given it by Lavoisier, from its being found to be the chief constituent part or principle of water, which is now well known to b<- a compound, consisting of a larger portion of hydro, gen, or inflammable air, and a smaller of oxygen, concerning which our readers may turn to the chapter on the constituent principles of WATER. Hydrogen gass enters very largely into all animal, most vegeta. ble, and a great variety of mineral compositions. It hence fre. OASS LIGHTS. 89 quently set at liberty by fermentations, or spontaneous decompo- sitions, is thrown forth from bogs and marshes, when, from a spark of natural electric fire, or some other accidental cause, it is ofVn seen burning under the form of ignes futui, or zsill-o'-the- whisps ; is occasionally kindled by similar cause-, in coal or me. taltic mines, with dreadful explosions and mischief, of which we have already given various examples in the preceding part of this work ; and is collected at times from substances that possess it in the largest abundance, for purposesof ECONOMICAL ILLUMINATION. It is under this last character that we are alone to consider it upon the present occasion. As the general principle of inflam- mations, all inflammable bodies necessarily contain it in a greater or less degree: such more especially as metals, alkoliols, oils, and bitumens or coals of every kind, and it constitutes the fine blue or purest part of the flame emitted from a candle or a fire, when made with good round coals, that melt into pitch. Of these dif- ferent substances, coals or bitumens may be obtained in the largest abundance, and with the greatest ease j and it is hence by a dis- tillation of these, that the gass is usually procured, which is em. ployed in gass lights. The means by which this is accomplished, the expence attending the process, and the great advantage of having recourse to it in extensive manufactories, or other places where large bodies or lengths of light are absolutely necessary, we shall now proceed to explain from a very valuable paper cum. municated to the Royal Society, by the ingenious artist and phi- losopher, who may justly be regarded as the inventor of the prac. tical application of the light of hydrogen gass to useful purposes. [Edit or. SECTION II. Application of the Gass from Coal to economical Purposes. By Mr. William Murdoch. THE facts and results intended to be communicated in this pa. per, are founded upon observations made, during the present winter, at the cotton manufactory of Messrs. Philips and Lee at Manchester, where the light obtained by the combustion of the gass from coal is used upon a very large scale; the apparatus for its production and application having been prepared by me at the works of Messrs. Boulton, Watt, and Co. at Soho. GASS LIGHTS. The wholfl of the rooms of this cotton mill, which is, 1 believe, the most f xtensire in the united kingdom, as well as its counting, houses and store-rooms, and the adjacent dwelling-houses of Mr. Lee, are lighted with the gass from coal. The total quantity of light used during the hours of burning, has been ascertained, by a comparison of shadows, to be about equal to the lights which 2500 mould candles of six to the pound would give ; each of the candles, with which the comparison was made consuming at the rate of 4-10ths of an ounce (175 grains) of tallow per hour. The quantity of light is necessarily liable to some variation, from the difficulty of adjusting all the flames, so as to be perfectly t-qual at all times ; but the admirable precision and exactness with which the business of this mill is conducted, afforded as excellent an opportunity of making the comparative trials I had in view, as is perhaps likely to be ever obtained in general practice. And the experiments being made upon so large a scale, and for a consider- able portion of time, may, I think, be assumed as a sufficiently accurate standard for determining the advantages to be expected from the use of the gass lights under favourable circumstances. It is not my intention, in the present paper, to enter into a particular description of the apparatus employed for producing the gas ; but I may observe generally, that the coal is distilled in large iron retorts, which during the winter season are kept con. stantly at work, except during the intervals of charging ; and that the gass, as it rises from them, is conveyed by iron pipes into large reservoirs, or gazometers, where it is washed and purified, pre- vious to its being conveyed through other pipes, called mains, to the mill. These mains branch off into a variety of ramifications (forming a total length of several miles), and diminish in size, as the quantity of gass required to be passed through them becomes less. The burners, where the gass is consumed, are connected with the above mains, by short tubes, each of which is furnished with a cock to regulate the admission of gass to each burner, and to shut it totally off when requisite. This latter operation may likewise be instantaneously performed, throughout the whole of the burners in each room, by turning a cock, with which each main is provided, near its entrance into the room. The burners are of two kinds : the one is upon the principle of the Argand lamp, and resembles it in appearance ; the other is GASS LIGHTS. (Jl a small curved tube wi(h a conical end, having three circular aper- tures or perforations, of about a thirtieth of an inch in diameter, one at the point of the cone, and two lateral ones, through which the s^ass issues, forming three divergent jets of flames, somewhat like a lleur-de lis. 'I he shape and general appearance of thif tube, has pnu ured it among the workmen, the name of the cock- spur burner. The number of burners employed in all the buildings, amounti to 271 Art-ands, and 633 cockspurs ; each of the former giving alight equal to that of four ondlcs of the description above, mentioned ; and each of the latter, a light equal to two and a quar. ter of t'» same randies; making therefore the total of the gass light a little more tnan equal force to that of 2500 candles When thus regulated, the whole of the above burners require an hourly supply of 1250 cubic feet of the gass produced from cannel coal : the superior quality and quantity of the gass produced from that material having Jv.-n it a decided preference in this situation, over every other coal, notwithstanding its higher price. The time during which the gass light is used, may, upon an are- ra_e of the whole year, be stated at least two hours per day of twenty-four hours. Jn some mills, where there is over work, it will be three hours ; and in the few where night-work is still con- tinued, nearly twelve hours. But taking two hours per day as the common average throughout the year, the consumption in Messrs. Philips' and Lee's mill, will be 1250 X 2 — 2500 cubic ftet of gass per day ; to produce which, seven hundred weight of camifl coal is required in the retort The price of the best Wigan cannel (the sort used) is 13|d. per cwt. (22s. per ton), delivered at the mill, or say about eit;ht shillings for the seven hundred weight. Multiplying by the number of working days in the year (313), the annual consumption of cannel coal will be 1 10 ton , and its cost £ I j5. About one. third of the above quantity, or say forty t >\>* of good common coal, value ten shillings per ton, is req ured tor fuel to he.it the retorts ; the annual amount of which -s j£~2(). The 110 tons of cannel coal when distilled, produce about 70 tons of good coak, which is sold upon the spot at Is. 4d. pt r cwt. and will therefore amou-it annually to the sum of £ 93. The quantity of tar produced from each ton of cannel coal it from eleven to twelve ale gallons, making a total annual produce 92 GASS LIGHTS. of about 1230 ale gallons, which not having been yet sold, I can. not detenriue its value; but whenever it come., to be manufactured in lai,:- quantities, it cannot be such as materially to influence the economical statement, unless indeed new applications of it should be discovered. The quantity of aquens fluid which came over in the course of the observations which I am now giving an account of, was not ex. artly ascertained, from some springs having got into the reservoir ; and as it has not been yet applied to any useful purpose, I may omit further notice of it in this statement. The intt rest of the capital expended in the necessary apparatus and buildings, together with what is considered as an ample allow, ance for wear and tear, is stated by Mr. Lee at about £550. per annum : in which some allowance is made for this apparatus being made upon a scale adequate to the supply of a still greater quan- tity of liulit. than he has occasion to make use of. ]!c is of opinion, that the cost of attendance upon candles would be as much, if not more, than upon the gass apparatus ; so tint in forming the comparison, nothing need be stated upon that score, on either side. The economical statement for one year then stands thus : Cost of 1 10 tons of cannel coal . £ . 125 Ditto of 40 tons of common ditto . 20 145 Deduct the value of 70 tons of coak . 93 The annual expenditure in coal, after deducting the value of the coak, and without allowing any thing for the tar, is therefore . . 52 And the interest of capital, and wear and tear of apparatus .... 550 making the total expense of the gass apparatus about £. GOO per annum. That of candles, to give the same light, would be about £. 2000. For each candle consuming at the rate of 4-10ths of an ounce of tallow per hour, the 2500 candles burning, upon an average of the- year, two hours per day, would, at one shilling per pound, the present price, amount to nearly the sum of money above, mentioned. If the comparison were made upon an average of thr«e hours GASS LIGHTS. ()<$ per day, the advantage would be still more in favour of fho gass light; the interest of the capital, and wear and tear of the appa. ratus, continuing nearly the same as in the former cese ; thus, 1250X3 = 3750 cubic feet of gass per day, which would be produced by lOfcwt. of cannel coals; this multiplied by the num. ber of working days, gires 168 tons per annum, which, valued as before, amounts to . . j£. 188 And 60 tons common coal, for burning under the retorts, will amount to . 30 218 Deduct 105 tons of coak, at 26*. Sd. . 140 Leaving the expenditure in coal, after deduction of the coak, and without allowance for the tar, at 78 Adding to which the interest, and wear and tear of apparatus, as before, the total annual cost will not be more than £. 650 ; whilst that of tallow, rated as before, will be £. 3000. It will readily occur, that the greater number of hours the gass is burnt, the greater will be its comparative economy ; although, in extending it beyond three hours, an increase of some parts of the apparatus would be necessary. If the economical comparison were made with oils, the advan. tages would be less than with tallow. The introduction of this species of light, into the establishment of Messrs. Philips and Lee, has been gradual; beginning in the year 1805, with two rooms of the mill, the counting-houses, and Mr. Lee's dwelling-house. After which it was extended through the whole manufactory, as expeditiously as the apparatus could be prepared. At first some inconvenience was experienced from the smell of the unconsumed, or imperfectly purified gas, which may in a great measure be attributed to the introduction of successive improve- ments in the construction of the apparatus, as the work proceeded. But since its completion, and since the persons to whose care it is confided, hive become familiar with its management, this incon. venience has been obviated, not only in the mill, but also in Mr. Lee's house, which is most brilliantly illuminated with it, to the exclusion of every other species of artificial light. T.'ie peculiar softness and clearness of this light, with its almost 94 OASS LIGHTS. unvarying intensify, have brought it into great favour with th* work-people. And its being fret- from the inconvenience and danger resulting from the sharks and frequent snuffing of candles, is a circumstance of maleri.il importance, as tending to diminish the hazard of fire, to which cotton mills are known to be much e»pos«d. The above particulars, it is conceived, contain such information as may teiul to illustrate the general advantages attending the use of the gass li^ht ; but nevertheless the Royul Society may perhaps not deem it uninteresting to be apprized of the circumstances which originally gave rise in my mind to its application, as an economical substitute for oils and tallow . It is now nearly sixteen years since, in a cour-e of experiments I was making at Kedruth, in Cornwall, upon the quantities and qualities of the gasses produced by distillation, from different mineral and vegetable substances, I was induced, by some obser. vations I had previously made upon the burning of coal, to try the combustible property of the gasses produced from it, as well as from peat, wood, and other inflammable substances. And being struck with tlie great quintities of gass which they afforded, as well as with the brilliancy of the light, and the facility of its production, I instituted several expeiiments, with a view of ascer- taining the cost at which it might be obtained, compared with that of equal quantities of light yielded by oils and tallow. My apparatus consisted of an iron retort, with tinned copper and iron tubes, through which the gass was conducted to a consider, able distance ; and there, as well as at intermediate points, was burned through apertures r the sanction of Messrs. Doulton, Watt, and Co., extended the apparatus at Soho foundry, so as to give li^ht to all the principal shops, where it is in regular use, to the exclusion of other artificial li^ht ; but I have preferred giving the results from Messr*. Philips' and Lee's apparatus, both on account of its greater extent, and the greater uniformity of the lights, which rendered the comparison with candles less difficult. At the same time I commenced my experiments, I was certainly unacquainted with the circumstance of the gass from coal having been observed by others to be capable of combustion; but I am since informed, that the current of gass escaping from Lord Dun. donald's tar ovens had been frequently fired ; and I find that Dr. Clayton, in a paper in volume xli., of the Transactions of the Royal Society, so long ago as the year 1739, gave an account of some observations and experiments made by him, which clearly manifest his knowledge of the inflammable property of the gass, which he denominates "the spirit of coals;" but the idea of applying it as an economical substitute for oils and tallow, does not appear to have occurred to this gentleman ; and I believe I may, without presuming too much, claim both the first idea of applying, and the first actual application of this gass to economical purposes. [PAzV. Trans. 1808, CHAP. VI. PHOSPHORUS OF KUNCKEL *. Phosphoric Bottles and Matches. 1 HOSPUORUS is well known to be a peculiar substance capable of inflaming or emitting a luminous aura, when exposed to the air of the atmosphere in a common temperature, and hence the basis of those curious sticks, matches, and bottles, which have of late * For other kinds of phosphorus, see the ensuing ch. vii. <)6 PHOSPHORUS. years been devised for giving light instantly and spontaneously, as soon as the) an- uncovered and COIDP in contact with the air. This has hitherto been r> garded as a simple combustible, and must be so regarded at pirsmt : though various experiments with very high degrees of voltaic electricity appear to have detected that it is a compound, possessing hydrogen and oxygen with a peculiar base. In consistence it resembles wax ; when pure it is nearly of the transparency of gum opal, of a colour varying from amber red to the faintest straw, highly combustible, and when oxygenated producing a strong and peculiar acid. It was discovered by a German chemist of the name of Brandt, about a hundred and fifty years ago, and the preparation was long kept a lucrative secret in the hands of a few persons. It was how. ever well known, from various facts that had escaped, that it was procured in some way or other from human urine ; and it has at length been found that it is in consequence of this substance con. taming a peculiar salt, hence denominated phosphoric salt (a mix. ture of phosphorus and oxygen), that phosphorus can be procured from it; as it has also that it can in like manner be procured from any other animal substance impregnated with the same material ; and consequently from the bones and crustaceous integuments of animals, in which it exists in a larger abundance, and which are now therefore usually employed for this purpose. One of the earliest chemists, next to Brandt, who devoted his at. tentioa in a very considerable degree towards obtaining this com. bustible was Kunckel. This chemist had seen the new product soon after its discovery by Brandt; and strongly desirous of pos- sessing the secret, he associated himself with a friend of Brandt's, whose name was Krafft, through whom he made an offer to purchase the discovery of its inventor. Brandt consented to disclose it ; but Krafft, instead of benefiting his colleague by the communica. tion, paid the money, and retained the secret to himself. Kunckel at this time knew nothing more of the preparation than that it was obtained by a series of processes from urine, through the medium of fire : and with this brief and unsatisfactory outline he set to work, and was at leng th fortunate enough to discover the method for himself; on which account the substance long went un- der the name of Kunckel's phosphorus. Mr. Boyle is also const, dered as one of the discoverers of phosphorus. He communicated the secret of the process of preparing it to the Royal Society of PHOSPHORUS. 07 London in 1680. .It is asserted, indeed, by Kraflft, that he disco. Tered the secret to Mr. Boyle having in the year 1678, carried a small piece of it to London to show it to the royal family ; but there is little probability that a man of such integrity as Mr. Boyle would claim the discovery of the process as his own, and commu- nicate it to the Royal Society, if this had not been the case. Mr. Boyle communicated the process to Godfrey Hankwitz, an apo- thecary of London, who for many years supplied Europe with phosphorus, and hence it went under the name of English phospho- rus. In the year 1774, the Swedish chemists, Gahn and Scheme, made the important discovery, that phosphorus is contained in bones of animals, and they improved the processes for procuring it. The most convenient process for obtaining phosphorus seems to be that recommended by Fourcroy and Vauquolin, which we shall transcribe. Take a quantity of burnt bones, and reduce them to powder. Put 100 parts of this powder into a porcelain or stone. ware bason, and dilute it with four times its weight of water. Forty parts of sulphuric acid are then to be added in small portions, taking care to stir the mixture after the addition of every portion. A violent effervescence takes place, and a great quantity of air it disengaged. Let the mixture remain for twenty. four hours, stir, ring it occasionally, to expose every part of the powder to the action of the acid. The burnt bones consist of the phosphoric acid and lime ; but (he sulphuric acid has a greater affinity for the lime than the phosphoric acid. The action of the sulphuric acid uniting with the lime, and the separation of the phosphoric acid, occasion the effervescence. The sulphuric acid and the lime combine toge« ther, being insoluble, and fall to the bottom. Pour the whole mix. ture on a cloth filter, so that the liquid part, which is to be received in a porcelain vessel, may pass through. A white powder, which is the insoluble sulphate of lime, remains on the filter. After thii has been repeatedly washed with water, it may be thrown away; but the water is to be added to that part of the liquid which passed through the filter. Take a solution of sugar of lead in water, and pour it gradually into the liquid in the porcelain bason. A whit« powder falls to the bottom, and the sugar of lead must be added so long as any precipitation takes place. The whole is again to be poured upon a filter, and the white powder uhich remains is to be well washed and dried. The dried powder is then to be mixed with one.sixth of ill weight of charcoal powder. Put thii mixture VOL. YI, « 98 PHOSPHORUS. into an ear'henwnre retort, and place it in » sand bafh, with the beak p'un.ed into . i v« -.^i-l <>l water Apply luat, and let if b<* prm nail) inrnnsed, till the retort becomes red-hot. As the heat increa-es, air.bnhhUs lu.^h in abundance through the beak of the retort, some of which are inflamed when they eome in contact with the air at (he surface of the water. A substance at last drop* out similar to m< Ited wax, which congeals und»T the water. This is phosphorus. To hate it quite pure, melt it in warm wat< r, and strain it several times through a piece of shamo) leather under the surface of the water. To mould it into sticks, tfke a glass funnel with a long tube, which must be stopped with a cork. Fill it with water, and put the phosphorus into it. Immerse the funnel in boiling water, and when the phosphorus is melted, and flows into the tube of the funnel, then plunge it into cold water, and when the phosphorus has become solid, remove the cork% and push the phos- phorus from the mould with a piece of wood. Thus prepared, it must be preserved in close vessels, containing pure water. When phosphorus is perfectly pure, it is semi-trans; arent, and has the consistence of wax. It is so soft, that it may be cut with a knife. Its specific gravity is from 1.77 to 2.03. It has an acrid and dis. agreeable taste, and a peculiar smell, somewhat resembling garlic. When a stick of phosphorus is broken, it exhibits some appear, ance of crystallization. The crystals are needle shaped, or long octahedrons; but to obtain them in their most perfect state, the surface of the phosphorus, just when it becomes solid, should be pierced, that the internal liquid phosphorus may flow out, and leave a cavity for their formation. When phosphorus is exposed to the light it becomes of a reddish colour, which appears to be an inci. pient combustion. It is therefore necessary to preserve it in a dark place. At the temperature of 99° it becomes liquid, and if air be entirely excluded, evaporates at 219°, and boils at 654. At the temperature of 43° or 44°, it gives out a white smoke, and is lumi- nous in the dark. This is a slow combustion of the phosphorus, which becomes more rapid as the temperature is raised. When phosphorus is heated to the temperature of 148" it takes fire, burn* with a bright flame, and gives out a great quantity of white smoke. Phosphorus enters into a combination with oxygen, azote, hydro. and carbon. Phosphorus is soluble in oils, and when thus • Ived forms what has been called liquid phosphorus, which maj be rubbed on the face aud bands without injury. It dissolves too TOUCHWOOD TINDEK-BOX. 99 in ether, and a v< ry beautiful experiment consists in pouring this photph'iric ether in small portions, and in a dark p'ac«-,on the njrface of hot water. The phosphoric matches consist of ph.. phonis ex. trcmrly ('ry. m'nutely dividtd, and perhaps a little oxy ol the tube, where the apunk to he kindled lies. kt In the piston with a single broad groove, the area of the circ-le, on which the column of uir rests, is much smaller, con. gequently the column itself is less. '1 he jesistance the air expe- riences in passing through the groove is next to nothing ; for we heai no noise on moving the piston backward and forward ; and as air expands in all directions, when the piston is moved, the column resting on the area of the circl<-, resting at the same time laterally on that which answers to the groove, it recedes f. <>in all the points of contact, and flows entirely through .the channel it finds opens. It is so true, that it wholly flows out, that the piston, when it touches the extremity of the tube, remains there; while with other pistons a sufficient quantity of air is retained to occasion a spring and repel them. u I think it proper to say a word or two on the quality of the spunk. The driest, softest, and least impregnated with nitre, should be chosen. In that of the best quality a pi« ce will not always be found equally jjood throughout. Some contains a great deal of nitre, and is kindled with more difficult)*. This may be known by the cold taste it leav< s on the tongue; or by kindling it: for when it has taken fire the nitre melts, and sometimes throws out sparks, that may be dangerous when they spirt out of the instrument, particularly if made with a cock. As it is usual to blow on the spunk, to try whether it be kindled, a spark may be thrown from it into the eye. This painful accident once hap. pened to me. " They who imagine that electricity kindles the spunk, consider these sparks as an incontrovertible proof of their opinion. I think they are mistaken in this case; yet I must not conceal a fact com. municated to me by Mr. Veau-Delaunay, which sec ms to confirm this opinion, of which he is a partisan. Out of twelve times, when he operated with the instrument without any spunk in it, he saw sparks emitted three times. There are strong reasons, however • The common spunk of the shops is prepared from agaric, which is fint boiled in water ; beaten well when dry ; steeped in a strong solution of salt- petre ; ;iii(l I i-ils drii d in an oven. If ihe solution of nilre be too strong, the agaric is loaded with (his salt, which retards its inflammation. TOUCHWOOD TINDKR-BOX. 103 for suspecting, that electricity is not the cause of the inflammation here. These I shall give in the second ptrt of this paper, con. eluding the present with an important observation on the construe- tion of pistons. '* If we could find an elastic substance sufficiently compact to be turned in a lathe, we should have perfect pistons, that would spring and adapt themselves to the inequalities of the tube, with- out suflering a bubble of air to t scape. I have made some with caoutchouc, softened before ihe fire, in order to give it a degree of elasticity more obedient to the inequalities of the tube. But on attempting to turn it in a lathe, it bent under the tool. Even the edge of a razor would not take hold it ; so that the piston remained uneven Mid almost ra^cd, and yielded like soft wax under the fingers. In this imperfect state it so far prevents the air from escaping, that a column of three inches is sufficient to kindle the spunk; but after a few strokes of the piston the heat dilates it to such a degree, that it cannot be moved witiiout considerable force. If a drop of oil be put on it, it moves easily ; but this soon spoils the instrument ; for the oil dissolves the caoutchouc, and forms a varnMi. which, as the piston grows hot, makes it adhere still more strongly to the si of the tube. " Might not these inconveniences be avoided, by arming the piston rod with caoutchouc, and covering this with leather ? If thi> process -ucceeded, it might be applied with advantage to all sorts of pumps. *' To attain, if possible, a knowledge of the principle of inflam- mation in the pneumatic tinder box, four things are to be considered — the materials of the tube, the matter contained in the tube, the materials of the piston, and the friction. Among the materials of the j)i-ton I include the grease, with which it is coated, to make it move more easily, and render it fitter to intercept the passage of the air. " In examining the question whether the spunk be kindled by ekctrity , I consider, " 1st, That no part of the instrument is insulated ; and that in- sulation is a necessary condition for producing sensible electricity with any of the machines we know. 1 say machines that we know, because the animal electricity, that manifests itself without insula- tion, is an exception to our mechanical means, and cannot here be taken into consideration. u4 104 TOrCHWOOD TINDER-BOX. " 2dly, The friction of the piston, which is a greasy body, against a metallic substance, is not calculated to produce electricity. *' 3dly, Experience demonstrates, that, unlo>s during storms, the atmosphere seldom exhibits any signs of electricity at the height in which we breathe it ; and that we must search for them with in- struments iu a more elevated region, or when electric clouds are passing over our heads. How then shall we estimate the infinitely small quantity of electric matter in a cubic inch of air, or even less, which the instrument contains ? " 4thly, It is not without great difficulty, that we can kindle spunk with strong electric sparks. I have discharged a large jar on spunk strewed with powdered resin, and it has remained uiu kindled, though the resin caught fire, and burned entirely away. " As long as the instrument was made with metallic substances only, we were obliged to confine ourselvps to the exterior marks of inflammation alone, without being able to assign the true cause, or at least furnish proofs of it. For to guess is not sufficient in natural philosophy ; we must demonstrate, in order to give to facts that degree of certainty, which befits science ; and this we cannot do here, without seeing what passes at the very point of inflam- mation. " The means are very simple. Nothing is necessary, but to substitute a glass for a metal tube. Those found in the shops being too slight, 1 applied to Mr. Laurent, the inventor of glass flutes, requesting him to procure me tubes of a similar quality. This artist, as much distinguished by his civility as by his talents, fur. nished me with three, which I fitted up. The first eight inches long by eight lines in diameter, did not kindle the spunk. The second, nine inches long by six lines and three quarters in diameter, kindled it completely. This being destroyed by accident, Itried the third, eight inches long by seven lines in diameter, which sue. ceeded equally well. " When the instrument is made to act, and the spunk kindles, we see a bright flash, that fills the capacity of the tube; and this light is so much the more vivid, in proportion as the compression is more rapid. If the compression be less powerful, the spunk does not kindle, but we perceive in the upper part of the tube a light vapour, that falls in undulations on the piston. When this has disappeared, if we draw back the piston, the vapour will re. appear, as long as there is any air in the tube. These effects may TOUCHWOOD TINDER-BOX. 105 be produced several times in succession, merely by pushing the piston with the hand. This vapour is so thin and diaphanous, that it is not perceptible in a strong light. It requires a sort of tw ilight to see it well. li But whence arises this vapour, and what is i(s nature ? As. suredly it is not furnished by the materials of the instrument ; it can only proceed, therefore, from what it contains, from the atmo- spheric air. Now, according to the present state of our knowledge, the air contains only nitrogen, oxygen, and a very small portiou of carbonic acid; all gassiform substances, which are kept in this state by the great quantity of caloric that penetrates them, and arc consequently heavier than it. But in compressing the air con. tained in the tube, what is the substance that must first give way ? Is it not that which is lightest, the caloric, that general solvent, that principle of fluidity and volatilization, which gives wings even to metals to raise themselves in the air ? Is then the vapour in ques- tion caloric, rendered visible by the approximation of its particles, •which are compressed by the surrounding air, as air becomes visible in passing through liquids ? This idea, which I am far from pre- senting as a thing proved, acquires more probability from the fol. lowing experiments. " I substituted hydrogen for common air, and the vapour showed itself as before j but the spunk did not take fire. With carbonic acid gass, and with nitrogen, the effects were the same. The latter, which contained a little nitrous gas, gave a somewhat denser vapour. Oxygen, lightly compressed, yielded a vapour more rare and transient than that from common air. It had scarcely fallen on the piston when it rebounded and disappeared. "When I compressed oxygen with a proper force for producing in. flammation, the spunk, which commonly takes fire only at the anterior part, was almost entirely burned : yet for this experiment I used a copper instrument, the piston of which lost air so much, that it would no longer kindle spunk (with common air). u Perhaps it will be said, that the vapour came from the greasy matter on the piston, which adheres to the sides of the tube ; and that it is expanded by the heat produced by the friction. To this I answer, in this case, 1st. The vapour should not shew itself be* fore the greasy matter is deposited on the sides of the tube ; yet it appears at the first stroke of the piston, before the tube becomes greasy. 2dly. It should show itself below the piston, in the part 106 TOUCHWOOD TINDER-BOX. which the piston has left ; but, on the contrary, it always shew* above. 3dly. There is no vapour, when the piston loses much air, if the friction be ever so rapid. -Ithly. The vapour should be more apparent, wli.n the pNton exerts its friction throughout the whole 1< n;;th of the tube, than when it is confined to a small part of its upper extremity ; yet the reverse frequently happens. 5thly. "XV hen the air is entirely decomposed no more vapour appears, but it shows itself again, if ever so little fresh air be introduced. " As it was essential to ascertain whether the vapour did not contain an acid principle, I fastened to the surface of the piston, with a little green wax, a piece of muslin dipped in infusion of litmus, and afterward dried. After twenty strokes of the piston the colour was not changed. I put on a second piece of muslin larger than the first, and the edges of which were loose. This was burned all round, without the colour of the rest being altered. La-tly, a third piece, which was wet, experienced no change of colour. '* From these experiments it follows, that no acid principle is developed ; that all ae'ri ,'orm substances, as well a» common air, produce a light vapour ; that no other gass, except ox)geu and common air, kindles the spunk ; that oxygen produces a much more powerful combustion than common air, consequently oxygen act* an important part in the inflammation ; that as it can exert its action only when set free by the decomposition of the common air, of which it constitutes a fourth part, it follows, that the air con. tained in the tube is decomposed by (he simple force of compres- sion ; that the vapour produced is not owing to the oxygen, since it shows itself equally in gasses that contain no oxygen ; that this vapour is the effect of some agent common to all gasses ; and that we may presume it is caloric itself, rendered visible by the sudden approximation of its p,irt> in a small space, where it rises to a tern, perature that is increased in the oxygen so as to kindle the spunk. '• It sometimes happens, that the spunk is turned black without kindling. In this case, as well as when it is kindled, if we draw back the piston in the tube, a dense vapour, that may be smelt, s out, which is not of the same nature as the former. That •how 8 itself before the inflammation: this always succeeds it. That is the princip'e of the inflammation : this a product furnished by the combustion of the spunk, of which it has the smell." [Le Douvier. Desmortiers. Journ. tie Physique. [ 107 ] CHAP. VIII. PUOsPHORESCENCU, OR SPONTANEOUS ILLUMINATION, ANIMAL, VEGETABLE, AND MINERAL. 1 ins is a most extraordinary and interesting subject, and a perusal of the three precefling chapt* rs will, in a considerable degree, en. able the reader to understand its general principles, though there is much that has hitherto eluded pursuit, and still remains to be deve- loped. Phosphorescence, in its broadest latitude, imports light thrown forth from substances that at the same time emit little or no heat at the common temperature of the atmosphere, and which are deno- minated phosphoric. The phosphorus properly so called, and which is usually under, stood in chemical books, and employed in chemical processes, is that commonly known by the name of Kunckel's phosphorus, and which we shall describe under that designation. But there are various other substances that possess, in different degrees, the same kind of illuminating power, and which it is hence necessary to take some notice of, as well as of the effects they produce. Of these kinds the phosphorescent substances there are three leading divisions. The first comprehends those which require a previous exposure to the solar or other light, in order to become luminous; whence they are calkd solar phosphor!: the second in- cludes those which, without any necessary previous exposure to light, be come luminous when moderately heated, which are deno. minated calorized phosphor!, or phosphor! from heat : the third comprehends those substances belonging to the animal and vege- table kingdoms, which emit li_ht spontaneously at the common temperature, without the necessity of a previous exposure to light) and these are called spontaneous phosphor!. SECTION I. Solar Phosphori. A CASUAL discovery by Vincenzio Cascariolo, a shoemaker of Bologna, about 1630, was the first circumstance that attracted the notice of philosophers to this curious subject. This man being in 108 SOLAR FHO&PIIOIII. quest of some alchemical secret was induced to calcine a parcel of Bolognian spar (a sub-species of heavy spar or native sulphat of ba- ryte), which he had procured from Monte Paterno, in the neigh, bourhood of the city; and observed, that whenever this substance, thus prepared, was placed in a dark room, after having been ex- posed to the sun, it continued to emit faint rays of li^ht for some hours afterwards. In consequence of this interesting discovery, the Bolognianspar came into considerable demand among natural philosophers, and the curious in general, so that the best way of preparing it was found an object of some pecuniary importance. This seems to have been hit upon by the family of Zagoni, who supplied all Eu- rope with Bolognian phosphorus, till the discovery of more power, ful phosphoric put an end to their monopoly. Margraaf, some jears afterwards, proved that other species of sulphated bar) te might, under particular management, be made to produce a simi. lar effect. In the year 1677, nearly half a century after the discovery of the Bolognian phosphorus, G. A. Baldwin, a native of Misnia, observed, that if nitrat of lime were evaporated to dryness, and then formed into a compact mass by fusion at a red heat, it would exhibit the same property of imbibing and emitting light as the former, only somewhat inferior in degree : hence this preparation obtained the name of Baldwin's phosphorus. lu 1730, M. du Fay, who is justly celebrated for his electrical researches, directed his attention to this subject, and observed, that all earthy substances, susceptible of calcination, either by mere fire, or when assisted by the previous action of nitrous acid, possessed the property of becoming more or less luminous when calcined and exposed for a short time to the light : that the most perfect of these phosphor! were limestones, and other kinds of carbonated lime, gypsum, and particularly the topaz ; and that some diamonds were also observed to be luminous by simple expo, sure to the sun's rays, without being previously ignited ; while flint, sand, jasper, agate, and rock crystal, were inphospho. rescent. Not long after, M. Beccaria discovered that a great variety of other bodies were convertible into phosphor!, by exposure to the mere light of the sun ; not only the varieties of carburet and sul. phat of lime, but organic animal remains3 and geodes lined with SOLAR 1'HOSPHORI. 109 minute crystals of quartz ; most compound salts, when clear and crystallized, particularly Glauber's nitre, and borax, were also found to be phosphorescent ; of vegetable substances all (In- fari- naceous and oily seeds, all the gums, and several of the resins, the white woods, and vegetable fibre, cither in the form of paper or linen ; also starch and loaf.sugar proved to be good phosphori, after being made thoroughly dry, and exposed to the direct rays of the sun. Sundry animal matters, by a similar treatment, were also converted into good phosphori, particularly bone, either fresh or calcined, sinew, glew, hair, horn, hooff, feathers, and fish shells. The same property, he observed, might be communicated to rock- chrysfal, and some other of the gems, by rubbing them against each other, so as to roughen their surface, and then placing them for some minutes in the focus of a lens, by which the rays of light wer« concentrated upon them at the same time that they were also mode- rately heated. In the year 176S, Mr. Canton contributed some important facts relative to solar phosphori, and communicated a method of prepar- ing a very powerful one, which, after the inventor, is usually called Canton's phosphorus. It is thus made : Calcine oyster- shells in the open fire for half an hour ; then select the widest and largest pieces, and mix them with flowers of sulphur in the pro- portion of one part of the latter to three parts of the former ; pack the whole closely in a crucible ; lute on a cover, and heat it pretty strongly for one hour ; when the crucible has again become quite cold, turn out its contents, and select the whitest pieces for use. Mr. Canton affirms, that hU phosphorus, inclosed in a glass flask, aud hermetically sealed, retains its property of becoming luminous for at least four years, without any apparent decrease of activity. Mr. Wilson found that a much greater brilliancy of colour would be produced by letting the oyster-shells come in direct con- tact with the burning coals, or other inflammable matter, and bj being covered with it ; and that if the covering matter be iron, the luminousness will be very bright ; if steel, still brighter and more iridescent ; but if plates of charcoal , most so of all. If a common box smoothing-iron, heated in the usual manner, be placed for half a minute on a sheet of dry, white paper, and the paper be then exposed to the light, and afterwards examined in a dark closet, it will be found that the whole paper will be luminous, that part however on which the iron had stood being much more shining than the rest. 110 ANIMAL AND VEGETABLE PMOSPHOHI. SECTION II. Colorized Phosphori. BESIDES those substances (hat are phosphorescent by exposure (• the rays of the sun, there are others which give out light when sim. ply heated. These materially differ from the former in this circum- stance, that after having been continued at any particular tempe- rature till their luminousm vs i* exhausted, they are. incapable of becoming again luminous, except at a greater heat than that to which they were first subjected. The range of temperature at which these bodies become luminous is not very extensive, com- mencing at about 400° Fahr. and terminating at the lowest visible red heat. The following is a li«t of substances exhibiting this, properly arranged by Mr. S. Wedge wood, according to the bril. liancy of the light. That variety of the blue fluor spar of Derbyshire, which, when scraped or struck, emits a fetid, bituminous odour, is the most phos- phorescent by heat of all the known substances: it glows, when moderately heated, with a pale emerald green light, sufficiently intense to be Tery visible even in daylight. To the second rank belong the common swine-stone, the common blue fluor, and red fel.spar, all which, as well as the following, exhibit a white or red. dish light. The third class includes the diamond, the ruby, carbo. nated baryte, chalk, colourless calcareous spar, sea-shells, granite, and white fluor. The fourth class comprehends white sand, car- bonated magnesia, heavy spar, flint, white marble, quartz, porcelain and earthen ware. The fifth class includes most of the metals, sulphat of potash, borax, white paper, white linen, sawdust, and asbestos. Under the sixth and last class are comprehended oil, wax, spermaceti, and butter when boiling or nearly so. Most of these are also phophorescent by friction. SECTION III. Animal and Vegetable Phosphori. IT is a curious fact, and though occasionally noticed, not gene, rally attend a confirmation of this conjecture, that the more glutinous the sea water is, the more it is disposed to become luminous, he observes, that one day they took a fish that was called a bonite, the inside of the mouth of which was so luminous, that, without any other light, he could read the same characters which he had before read by the light in the wake of the ship ; and the mouth of this fish was full of a viscous matter, which, when it was rubb- ed upon a piece of wood, made it immediately all over luminous ; though, when the moisture was dried up, the light was extin. guished. The abbe Nollet was much struck with the luminousness of the sea when he was at Venice in 1749 ; and after taking a great deal of pains to ascertain the circumstances of it, concluded that it was occasioned by a shining insect; and having examined the water very often, he at length did find a small insect, which he particu- larly describes, and to which he attributes the light. The same hypothesis had also occurred to M.Vianelli, professor of medicine in Chioggia, near Venice; and both he and M. Grizellini, a phy. sician in Venice, have given drawings of the insects from which they imagined this light to proceed. The abbe was the more confirmed in this hypothesis, by observ- ing, some time after, the motion of some luminous particles in the sea. For, going into the water, and keeping his head just above the surface, he saw them dart from the bottom, which was covered with weeds, to the top, in a manner which he thought very much resembled the motions of insects ; though, when he endeavoured to catch them, he only found some luminous spots upon his hand- kerchief, which were enlarged when he pressed them with hit finger. M. Le Roi, making a voyage on the Mediterranean, presently after the abbe Nollet made his observations at Venice, took no. tice, that in the day-time the prow of the ship in motion threw up many small particles, which, falling upon the water, rolled upon the surface of the sea for a few seconds before they mixed ANIMAL AND VEGETABLE PHOSPHOR1. with it; and in the night th<- same particles, as In- concluded, had the appearance of lire. Taking n quantity of the water, the same small sparks appeared whenever it was agitatnl ; but, as was ob- served with respect to Dr. Beal's experiments, every successive agitation produced a less effect than the preceding, except after being suffered to rest awhile ; for then a fresh agitation would make it almost as luminous as the first. This water, he observed, would retain its property of shining by agitation a day or twoj but it disappeared immediately on being set on the fire, though it was not made to boil. M. Ant. Martin made many expeiiments on the light of fishes, with a view to discover the cause of the light of the sea. He thought that he had reason to conclude, from a great variety of experiments, that all sea. fishes have this property ; but that it is not to be found in any that are produced in fresh water. Nothing in his opinion depended upon the colour of the fishes, except that he thought that the white ones, and especially those that had •white scales, were a little more luminous than others. This light, he found, was increased by a small quantity of salt; and also by a small degree of warmth, though a greater degree extinguished it. This agreper debility ; and thus by alternate!* adding fresh salt, and new supplies of water, he has sometimes revived the same light after ten extinctions. Great cold and heat are also found to extinguish it ; yet a moderate heat ren. ders it more brilliant : it begins to be extinguished at 96° j and when the thermometer is raised to 100 it can be no more revived. It is however capable of being revived, after being frozen by frigo. ritic mixtures. It is therefore an anomalous fact, that the light of dead glow, worms continues to augment in heated water, increased to 114 degrees. Luminous appearance of the Sea. FROM what has already been observed, this beautiful and brif. iiant phenomenon is not difficult to be accounted for in most cases : for the vast mass of the ocean contains in itself whatever has the greatest tendency to the production of such a phenomenon. It is the natural province of the greater number of those animals that secrete light from peculiar organs with which they are endowed for this purpose, of phloades, nereids, medusas, ami luminous can. cers ; it holds in its immense bosom, at all times, an enormous quantity of that kind of animal matter, (marine fishes) which is most disposed to throw forth its latent light, in an aggregate and visible form, during its first progress of decomposition ; and unites the different circumstances which chiefly favour such an evolution ; such, for instance, as a fluid menstruum, temperate warmth, and a solution of muriat of soda or common salt. If then we see occasionally, in vegetable matter undergoing a slow decomposition, as in rotten wood, a certain portion of light poured forth in a visible form ; if we see it issuing in a still greater degree from bones and shells that have undergone the process of calcination ; if we see it still more freely at times, and under circumstances, thrown forth from the animal exuvia of church, yards, and adhering to the surface of the spot from which it issues, in like manner as the light scraped off from the scales of pieces of putrescent fishes, immersed in salt water, adheres to the knife or the fingers that are employed for this purpose ; how much more easily may we expect to see it thrown forth, and in how much 128 SPONTANEOUS COMBUSTION. larger quantities, from different parts of the ocean, utid^r circum- stances that may favour its escape; often adhering to the sides of vessels, or of their oars us they are alternately raistd from the water, and producing a long line, or an extended sheet, of won. derful brilliancy, not unfrequently variegated by every playfulness of colour. It appears obvious, moreover, that it is not to one cause only, but to many, that such phenomena are to be ascribed, at different periods, and in different parts of the world. Linnaeus inclined to confine it chiefly to vast flocks of the nereis tribe : but we have already observed, that even at sea, and among living animals, medusas, sapias, pennatulas, pyrosomas, and phloades equally concur : while, on other occasions, the waves appear brilliantly illuminated, and through a very extensive range, without a trace of any living substance whatever, possessed of a luminous power ; and can only acquire their light from the decomposition of dead animal matter. [Pantologia* CHAP, IX. SPONTANEOUS COMBUSTION. IN the preceding chapter we have confined our remarks to sub. stances which spontaneously emit light with little or no increase of sensible heat. In the present we shall have to notice other sub> stances that spontaneously emit heat, and burn, either in conjunc- tion with light, or, as very frequently happens, without any light whatever : in the course of which we shall have to glance at some very remarkable and interesting effects, which to this hour have never been satisfactorily explained. Spontaneous combustion, as a general fact, is well known ; and the more common causes are too obvious to be enlarged upon ; we need only refer to friction and its effects, to the heat produced by the slacking of lime when in contact with combustible matter, to the fermentation of hay, of dunghills, and of similar materials similarly disposed. But besides these more common causes, eipcrience has shewn SPONTANEOUS SUBSTANCES. 129 •that many vegetable substances, highly dried and heaped together, will heat, scorch, and at last burn into dame. Of these the moat remarkable is a mixture of the expressed oil of the farinaceous feed;), as rape or linseed oil, with almost any other dry vegetable fibre, such as hemp, cotton, matting, &c. and still more, if also united with lamp. black, or any carbonaceous subsianco. These mixtures if kept for a time undisturbed, in close bundles, and in a warm temperature, even in small quantities, will often heat, and burn with a mouldering fire for some hours ; and if air be admitted freely, will then burst into flame. To this without doubt may be attributed several accidental conflagrations in storehouses, and places where quantities ef these substances are kept, as has been proved by direct experiments. The most important of these expe- riments were mad* by Mr. George, and a committee of the Koyal Academy at P*itersburgh. in the year 1781, in consequence of the destruction, by fire, of a frigate in the harbour of Cronstadt; the conflagration of a large hemp magazine, in the same place, in the same year; and a slight fire on board another frigate, in the same port, in the following year. These accidents led to a very strict examination of the subject, by the Russian government ; when it came out, that at the time of the second accident, several parcels of matting, tied with pack, thread, in which the soot of burnt fir-wood had been mixed with oil, for painting the ship, had been lying some time on the floor of the cabin, whence the fire broke out. In consequence of which, the following experiments were made: forty pounds of fir. wood soot were soaked with about thirty-five pounds of hemp oil var. nish, and the whole was wrapped up in a mat, and put in a close cabin. In about sixteen hours it was observed to give out a smoke, which rapidly increased, and when the door was opened, and the air freely admitted, the whole burst into a flame. Three pounds of fir-black were mixed with five pounds of hemp-oil varnish, and the whole bound up in linen, and shut up in a chest. In sixteen hours it emitted a very nauseous putrid smell and steam ; and two hours afterwards it was actually on fire, and burnt to ashes. la Another experiment, the same occurrences took place, but not till the end of forty-one hours after the mixture had been made ; and in these and many similar experiments, they all succ« -cd- d better, and kindled sooner on bright, than on rainy days. Chimney soot used instead of lamp-black did not answer, nor was any «ffect TOL. VI. K SPONTANEOUS SUBSTANCES. produced, when oil of turpentine was substituted for the hemp or rape. oil. In general it was found, that the accension took place more readily with the coarser and more unctuous fir-black, than with the finer sorts ; but the proportions of the black to the oil did not appear to be of any great moment. Sometimes, in wet wea- ther, these mixtures only become hot for some hours, and UK n cooled again, without actually taking fire. In all these cases the soot or black was from wood, and not coal. The presence of lamp-black, or any other dry carbonaceous matter, is not necessary however ; for a spontaneous inflammation will take place in hemp or cotton, simply soaked in any of these expressed oils, when in considerable quantity, or under circum- stances favourable to this process, as in very hot weather, or closely shut up. An accident of this sort happened at Gainsbo- rough, in Lincolnshire, in July, 1794, with a tale of yarn of 1201b., accidentally soaked in rape-oil; which, after remaining in a warehouse for several days, began to smoke, to emit a most nauseous smell, and finally to burst out in a most violent flame. A similar accident, with a very small quantity of the materials, happened at Bombay. A bottle of linseed oil had been left stand, ing on a chest; this had been thrown down by accident in the night, the oil ran into a chest which contained some coarse cotton cloth, and in the morning the cloth was found scorching hot, and reduced nearly to tinder, and the wood of the chest charred on the inside. On subsequent trial, a piece of the same cloth was soaked in- oil, shut up in a box, and in no longer time than three hours it was found scorching hot, and on opening the cloth it burst into fire. Similar to tin's is the spontaneous combustion of wool, or woollen yarn, which has occasionally happened when large quantities have been kept, heaped up in rooms little aired, and in hot weather. The oil with which wool is dressed, which is gene- rally rape. oil, appears the chief agent in this combustion. Even high dried, oily, or farinaceous matter of any kind, will alone take fire, when placed in circumstances very favourable to this process. Rye flour roasted till half parched, and of the colour of coffee, and wrapped up in a linen cloth, has been found to heat violently, and to destroy the cloth. Wheat flour, when heated in large quantities, and highly dried, has been known to take fire in hot weather, causing accidents in granaries ;iud bakers' shops. An accident of this kiud is related by Count Morrozzo, in the Memoirs SPONTANEOUS SUBSTANCES. 131 of the Turio Academy, to have happened at a flour warehouse at Turin, containing about three hundred sacks of flour. It began by a violent explosion, on a lamp being brought into the ware, house, and the whole was soon after in flames. Charcoal alone also has boon known to take fire in powder-mills, when quantities of it in powder have been kept for some time closely packed. Another, and totally different species of spontaneous combuKtion, is that which occurs during the oxygenation or vitriolization of pyrites, or sulphurets of iron, copper, &c. A most curious, and, if not well authenticated, a scarcely ere- dible species of spontaneous inflammation, is that in a few rare instances, known to occur in the human body. It is not quite certain indeed, whether the first inflammation has been quite spon. taneous, or caused by the approach of a lighted substance ; but in these melancholy accidents, the body of the unfortunate sufferers has been brought to a state of such high combustibility, that the flame once kindled, has gone on without other fuel, to the entire destruction of every part, (the bones and extremities excepted) and, as it appears, has been attended with actual flame, of a lam. bent faint light. This change is the more remarkable, as the human body, in all its usual states, both of health and disease, is scarcely at all of itself combustible, and cannot be reduced to ashes without the assistance of a very large pile of faggots, or other fuel ; as universal experience, in the very ancient mode of sepul. ture, and the history of martyrdoms, abundantly shews. Cases of this human combustion on record, have occurred in diflerent coun- tries. Two of them, well authenticated, are recorded in the Philosophical Transactions, and occurred in England ; and a fe\r others in Italy, France, and elsewhere. In all but one, the sub. jects of them have been females rather advanced in life, of indolent habits, and apparently much addicted to spirituous liquors. The accident has generally been detected by the penetrating fetid •mell of burning and sooty films, which have spread to a great distance ; and the sufferers have in every instance been discovered dead, and with the body more or less completely burnt up, leaving in the burnt parts only an oily, crumbly, sooty, and extremely fetid matter. Another circumstance in which these cases all agree, is the comparative weakness of the heat produced by this combus- tion, notwithstanding the very complete disorganization of the body itself, so that the furniture of the room, wooden chairs, &c. K2 132 CHEMICAL AFFIKITT. found within the reach of the burning body, were in many in. Btanci-s absolutely unhurt, and in others only scorched ; the heat not having been strong enough to set them on fire. It is impossi- ble to give an adequate reason for this remarkable change ; nor does it seem before the very time of the accident to have product il any Tory sensible alteration in the appearance and functions of the body, which is certainly a most astonishing circumstance. With regard to the effect which the use of ardent spirits is supposed to have in this case, it is impossible not to imagine that this cause may contribute largely to this change ; but the instances of the abuse of spirits are so innumerable, and those of this surprising combustion are so extremely rare, that very little satisfaction can be obtained from this explanation. [Pantologta. CHAP. X. CHEMICAL AFFINITY. 1. ALL the great bodies which constitute the solar system arc urged towards each other by a force which preserves them in their orbits, and regulates their motions. This force has received the name of attraction. Its nature is unknown : whether it be inhe- rent in these bodies themselves, or the consequence of some foreign agent, are questions altogether beyond the reach of philosophy, because we have no method of deciding the point. One would be more inclined to the first supposition than to the other, as we can conceive no foreign agent sufficient to explain the planetary mo. tions unless an intelligent one ; and, for any thing which we know to the contrary, it was as easy for the Creator to have bestowed on the planets the power of acting on each other at a distance, as the power of being acted on, and receiving motion from other sub- stances. 2. Sir Isaac Newton demonstrated, that this planetary attrac- tion is the same with gravitation, or that force by which a heavy body is urged towards the earth ; that it is possessed, not only by th* planets as wholes, but by all their component parts also j that CHEMICAL AFFINITY. 133 it is mutual ; that it extends to indefinite distances ; and that all bodies, as far as is known, are possessed of it. 3. When two bodies are brought within a certain distance, they adhere together, and require a considerable force to separate them. This is the case, for instance, with two polished pieces of marble or glass. When a piece of metal, or indeed almost any body whatever, is plunged into water and drawn out again, its surface is moistened, that is to say, part of the water adheres to it. When a rod of gold is plunged into mercury, it comes out stained indelibly with a white colour, because it retains and carries with it a portion of the mercury. Hence it is evident that there is a force which urges these bodies towards each other, and keeps them together ; consequently there is an attraction between them. Bodies, therefore, are not only attracted towards the earth and the planetary bodies, but towards each other. The nature of this attraction cannot be assigned any more than that of gravitation ; but its existence is equally certain, as far at least as regards by far the greater number of bodies. 4. In all cases we find the particles of matter united together in masses ; differing indeed from each other in magnitude, but con- taining all of them a great number of particles. These particles remain united, and cannot be separated without the application of a considerable force ; consequently they are kept together by a force which urges them towards each other, since it opposes their separation. Consequently this force is an attraction. Thus we see that there is a certain unknown force which urges bodies towards each other ; a force which acts not only upon large masses of matter, as the sun and the planets, but upon the smaller component parts of these bodies, and even upon the particles of which these bodies are composed. Attraction, therefore, as far as we know, extends to all matter, and exists mutually between all matter. It is not annihilated at how great a distance soever we may suppose bodies to be placed from each other; neither does it disappear, though they be placed ever so near each other. The nature of this attraction, or the cause which produces it, is alto, gether unknown ; but its existence is demonstrated by all the phenomena of nature. 5. This attrac ion was long accounted for, by supposing that there existed a certain unknown substance, which impelled all bodies towards each other; a hypothesis to which philosopher* Kl l.'U CHEMICAL AFFINITY. had recourse, from an opinion long admitted as a first principle, ** that no body can act where it is not," as if it were more diffi- cult to conceive why a change is produced in a body by another which is placed at a great distance, than why it is produced by one which is situated at a small distance. It is not only impos- sible to explain the phenomena of attraction by impulsion, but it is as difficult to conceive how bodies should be urged towards each other by the action of an external substance, as how they should be urged towards each other by a power inherent in themselves. The fact is, that we can neither comprehend the one nor the other; nor can any reason be assigned why the Almighty might not as easily bestow upon matter the power of acting upon matter at a distance, as the power of being acted upon and changed by matter in actual contact. But farther, we have no reason for supposing that bodies are ever in any case actually in contact. For a'l bodies are diminished in bulk by cold, that is to say, their particles are brought nearer to each other, which would be impossible, unless they had been at some distance before the application of the cold. Almost all bodies are diminished in bulk by pressure, and consequently their particles are brought nearer each other; and the diminution of bulk is always proportional to the pressure. Newton has shewn, that it required a force of many pounds to bring two glasses within the 800th part of an inch of each other; that a much greater was necessary to diminish that distance; and that no pressure w hit- ever was capable of diminishing it beyond a certain point. Con. sequ< ntly there is a force which opposes the actual contact of bodies ; a force which increases inversely as some power or func- tion of the distance, and which no power whatever is capable of overcoming. Boscovich has demonstrated, that a body in motion communicates part of its motion to another body, before it actually reaches it. Hence we may conclude that, as far as we know, there is no such thing as actual contact in nature, and that bodies of course always act upon each other at a distance. Even impul- sion, therefore, or pressure, is an instance of bodies acting on each other at a distance; and therefore is no belter explanation of attraction than the supposition that it is an inherent power. We must therefore be satisfied with considering attraction as an un- known power, by which all bodies are urged towards each other. It is a power which acts constantly and uniformly, in all times and CHEMICAL AFFINITY. 135 places, and which is always diminishing the distance between bodies, unless when they are prevented from approaching each other by some othrr force equally powerful. 6. The change which attraction produces on bodies, is a dimi- nution of their distance. Now the distances of bodies from each other are of two kinds, either too small to be perceived by our senses, or great enough to be easily perceived and estimated. In the first case, the change of distance produced by attraction must be insensible ; in the second case it must be visible. Hence the attractions of bodies, as far as regards us, naturally divide them, selves into two classes: 1. Those which act at sensible distances; 2. Those which act at insensible distances. The first class obviously applies to bodies in masses of sensible magnitude ; the second class must be confined to the particles of bodies, because they alone are at insensible distances from each other. 7. It has been demonstrated, that the intensity of the first class of attractions varies with the mass and the distance of the attract, ing bodies. It increases with the mass of these bodies, but dimi- nishes as the distance between them increases. Hence we see that hi this class of attractions every particle of the attracting bodies act, since the sum of the attracting force is always proportional to the number of particles in the attracting bodies. Why it dimi- nishes as the distance increases, it is impossible to say ; but the fact is certain, and is almost incompatible with the supposition of impulsion as the cause of attraction. The rate of variation has been demonstrated to be inversely as the square of the distance, in all cases of attraction belonging to the first class. 8. The attractions belonging to the first class must be as nume- rous as there are bodies situated at sensible distances ; but it has been ascertained that they may be all reduced to three different kinds; namely, 1. Gravitation; 2. Electricity; 3. Magnetism. The first of these has been shewn by Newton to belong to all matter, as far as we have an opportunity of examining, and there, fore to be universal. The other two are partial, being confined to certain sets of bodies, while the rest of matter is destitute of them : for it is well known, that all bodies are not electric, and that scarcely any bodies are magnetic, except iron, cobalt, nickel, and chromium. The intensity of these three attractions increases as the mass of R4 fill. MICAL AFFINITY. the attracting bodies, and diminishes as the square of the distance increases. The first extends to the greatest distance at which bodies are known to be separated from each other. How far elec. tricity extends has not beta ascertained ; but magnetism <-xtcnds at least as far as the semidiameter of the earth. All bod 'CM possess gravity ; but it has been supposed that the other two attractions are confined to two or three subtile fluids, which constitute a part of all those bodies which exhibit the attractions of electricity or magnetism. This may be so ; but it is not, and scarcely can be demonstrated. 9. The absolute force of these attractions in given bodies can only be measured by the force necessary to counteract the ellt-ct of these attractions, or by the space which given bodies, acted on merely by these attractions, traverse in a given time. If we compare the different bodies acted on by gravitation, we shall find that the absolute force of their gravitation towards each other is in all cases the same, piovided their distances :-jn> each other, and their mass, be the same ; but this is by no means the case with electrical and magnetic bodies. In them the forces by. which fhey are attracted towards each other, called electricity and magnetism, are exceedingly various, even when the mass and the ('istance are the same. Sometimes these forces disappear almost entirely ; at other times they are exceedingly intense. Gravity, therelore, is a force inherent in bodies ; electricity and magnetism not .-o : a cir. cumstance which renders the opinion of their depending upon peculiar fluids exceedingly probable. If we compare the absolute force of these three powers with each other, it would appear that the intensity of the two last, every thing else being «qual, is greater than that of the first ; but their relative intensity cannot be compared, and is therefore unknown. Hence it follows that these different attractions, though they follow the same laws of variation, are not the same in kind. 10. The attractions between bodies at insensible distances, and which of course are confined to the particles of matter, have been distinguished by the name of affinity ; while the term attraction has been more commonly confined (o cases of sensible distance. Now the particles of matter are two kinds, either homogeneous or heterogeneous. By homogeneous particles, I mean particles which compose the same body ; thus all particles of iron are homoge. CHEMICAL AFFINITY. 137 neous. By heterogeneous particles arc meant those which com. pose different bodies ; thus a particle of iron, and a particle of lead, are heterogeneous. Homogeneous affinity urges the homogeneous particles towards each other, and keeps them at insensible distances from each other; and consequently is the cau<=e why bodies almost always exist united together, so as to constitute masses of sensible magni- tude. This affinity is usually denoted by tlie term cohesion, and sometimes by adhesion, when the surfaces of bodies are only referred to. Homogeneous affinity is nearly universal ; as far at is known, caloric and li^ht only are destitute of it. Heterogeneous affinity urges heterogeneous particles towards each ott.er. and keeps them at insensible distances from each other, and of course is the cause of the formation of new integrant particles, composed of a certain number of heterogeneous par- ticks. These new integrant particles afterwards unite by cohe- sion, and form masses of compound bodies. Thus an integrant particle of water r composed of particles of hydrogen and oxygen, urged towards each other, and kept at an insrmible distance by heterogenecus Affinity; and a mass of water is composed of an indefinite number of integrant particles of that flu-d, urged to, wards each other by homogeneous j ffi ity. Heterogeneous affinity is un-ersal. as far as is known : that is to -ay. there is no body whose particlf s art* not attracted by the particles of some other body ; but whether the particles of all bodies hare an affinity for the particles of all other bodies, is a point which we have no means of ascertaining. It is, however, exceedingly probable, and has been generally taken for granted ; though it is certainly assum- ing more than oven analogy can warrant. 11. Affinity, like sensible attraction, varies with the mass and the distance of the attracting bodies. That cohesion varies with the mass, cannot indeed be ascertained ; because we have no method of varying the mass, without at the same time altering the distance. Hut in cases of the adhesion of the surfaces of homo, geneous bodies, which is undoubtedly an instance of homogeneous affinity, it ha* been demonstrated, that the force of adhesion in. creases with the surface, that is to say, with the mass ; for the cumber of adhering particles must increase with the surface. That heterogeneous affinity increases with the mass, has been observed long ago in particular instances, and has been lately ];38 CHEMICAL AFFINITY". demonstrated by Berthollet to hold ia every case : thus a givert portion of water is retained more obstinately by a large quantity of sulphuric acid, than by a small quantity. Oxygen is more easily abstracted from those oxides, which are oxidized to a maxi. muni, than from those which are oxidized to a minimum ; that is to say, that a large mass of metal retains a given quantity of oxygen more violently than a small mass. Lime deprives pot. ash of only a portion of its carbonic acid ; and sulphuric acid deprives phosphoric acid of only a portion of the lime with which it is united in phosphate of lime, in these, and many other instances that might be t mum rated, a small portion of one body is retained by a given quantity of another, more strongly than a large quantity. And Berthollet has shewn, that in all cases a large quantity of a body is capable of abstracting a portion of another, from a small portion of a third ; how weak soever the affinity between the first and second of these bodi< s is, and how strong soever the affinity between the second and the third. Thus when equal quantities of the following bodies were boiled together, C Sulphate of barytes f Oxalate of lime J Potash ' 1 Potash f Sulphate of potash . j Phosphate of lime " £Soda ' (Potash C Sulphate of potash 6 j Carbonate of lime £ Lime ( Potash the unoombined base abstracted part of the acid, from the base with which it was previously combined ; though in every one of these instances it was retained by that base, by an affinity consi- dered as stronger. The same division of the base took place when equal quantities of oxalate of lime, and nitric acid, were boiled together. We have seen that sensible attraction, though in all cases the same kind of force, is not always the very same force ; for though the mass and the distance of two bodies bn equal, the abso. lute force by which they are attracted towards eaoh other by gra. vitation is not equal to the force by which they are attracted to. wards each other by magnetism. The forces of sensible attraction are three in number, namely, gravitation, magnetism, and elec- tricity ; the first is always the same when the mas* and distance are the same, but the two la^t vary even when the mass and distance continue unaltered. CHEMICAL AFFINITY. JSQ The forces of affinity, though also the same in kind, are still more numerous than those of sensible attraction ; for instead of three, they amount to as many as there an- heterogeneous bodies. The rate, indeed, at \v' ' *ht , vary when the distance of the attracting bodies increases _>r • 'iminishes, is probably the same in all. and so is also their variations as far ;is it regards the mass. But even when both of these ' ircumstances, as far as we can estimate them, are the same, the affinity of two bodi< s for a third is not the same. Thus barytes has a stronger affinity for sulphuric acid than potash has : for if equal quantities of each be mixed with a small portion of s'llphuric a*.id, the barytes seizes a much greater proportion of the acid than the potash does. This difference in intensity extends to ".articles of all bodies ; for there are scarcely any two bodies whose particles have precisely the same affinity lor a third; and scarcely any two bodie.s. the particles of each ol which cohere to- gether with exactly the same force. It is this difference in intensity which constitutes the most im- portant characteristic mark of affinity, and which explains the dif. ferent decompositions and changes which one body occasions in others. Thus it appears at first sight, that there are as many different affinities as there are bodies ; and that affinity, instead of being one force like gravitation, which is always the same when the cir- cumstances are the same, consists of a variety of different forces, regulated, indeed, by the same kind of laws, but all of them dif. ferent from each other. These affinities do not vary like magne. tism and electricity, though the mass continues the same, but are always of equal intensity when other circumstances are equal. Hence it is reasonable to conclude, that these affinities cannot, like magnetism and electricity, depend upon peculiar fluids, the quantity of which may vary ; but that they are permanent forces, inherent in every atom of the attracting bodies. 12. It is very possible that this variation of intensity, which forms so remarkable a distinction between affinity aud gravitation, may be only apparent and not real. For even in gravitation the intensity varies with the distance and the ma>s, and the same vari. ation holds in affinity. But as the attraction of affinity acts upon bo* dies situated at intensible distances from each other, it is evident that, strictly speaking, we have DO means of ascertaining that distance ; and coujequently that it may vary without our discover. 140 CHEMICAL AFFINITY. ing the variation. But every such variation in distance must occasion a corresponding variation in the intensity of the attracting force. It may be, then, that barytes attracts sulphuric acid with greater intimity than potash, because the particles of barytes, whon they act upon the acid, are at a smaller distance from it than the particles of the potash are. But it may be asked, Why, if barytes, potash, and sulphuric acid, are all mixed together in water, th»- particles of potash do not ap- proach as near the acid as those of the barytes, since they are both at liberty to act ? To this it may be answered, that in all proba. bility they do approach each of them to the same apparent dis- tance, (if the expression be allowed), but that, notwithstanding, their real distance may continue different. The particles of bo. dies, how minute soever we suppose them to be, cannot be desti- tute of magnitude. They must have a certain length, breadth, and thickness, and therefore must always possess some particular figure or other. These particles, indeed, are a great deal too mi. nute for us to detect their shape ; but still it is certain that they must have some shape. Now it is very conceivable that the par. tides of every particular body may have a shape peculiar to them, selves, and differing from the shape of the particles of every other body. Thus the particles of sulphuric acid may have one shape, those of barytes another, and those of potash a third. But if the particles of bodies have length, breadth, and thick, ness, we cannot avoid conceiving them as composed of an inde- terminate number of still more minute part'cles or atoms. Now the affinity of two integrant particles for each other must be the sum of the attractions of all the atoms in each of these particles for all the atoms in the other : but the sum of these attractions must depend upon the number of attracting atoms, and upon the distance of these atoms from each other respectively ; and this dis. tance must depend upon the figure of the particles. Ft»r it is ob. rious, that if two particles, one of which is a tetrahedron and the other a cube, and whi'-h contain the same number of atoms, be placed at the same relative distance from a third particle, the sum of the distances of all the atoms of the first particle from all the atoms of the third particle, will be less than the sum of the dis- tances of all the atoms of the second particle from those of the third. Consequently, in this case, though the apparent distance of the particles be the same, their real distance is different ; and CHEMICAL AFFINITY. 141 of course the cube will attract the third particle more strongly than the tetrahedron ; that is, it will have a greater affinity for it than the tetrahedron. But if thr particles of bodies differ from each other in figure, they may differ also in density and in size : and this must also alter the absolute force of affinity, even when the distances and the figure of the attracting particles are the same. The first of these two circumstances, indeed, may be considered as a difference in the mass of the attracting bodies, and th refore may be detected by the weight of the aggregate ; but the second, though also no less a variation in the mass, cannot be detected by any such method, though its effect upon the strength of affinity may be very con. siderable. There is no doubt that, upon the supposition that such differ, ences in the figure, density, and size of the attracting particles, really exist, and it is in the highest degree probable that they do exist, the variation in intensity which characterises chemical affi- nity may be accounted for, without supposing the intensity of affinity, as a force inherent in the ultimate particles or atoms of bodies, is really different. The same thing may be applied to electricity and magnetism. It is certainly possible, therefore, that attraction, both sensible and insensible, may not only vary at the same rate, and according to the same laws, but be abso- lutely the same force inherent in the atoms of matter, modified merely by the number and situation of the attracting atoms. This is certainly possible ; and it must be allowed that it corresponds well with those notions of the simplicity of nature, in which we are accustomed to indulge ourselves. But the truth is, that we are by no means good judges of the simplicity of nature ; we have but an imperfect glimpse here and there through the veil with which her operations are covered ; and from the few points which we see, we are constantly forming conjectures concerning the whole of the machinery by which these operations are carried on. Superior beings smile at our theories as we smile at the reasonings of an infant ; and were the veil which conceals the machine from our view to be suddenly withdrawn, we ourselves, in all proba- bility, would be equally astonished and confounded at the wide difference between our theories and conjectures, and the real pow. ert by which the machinery of the universe is moved. Let us not therefore be too precipitate in drawing general conclusions ; but 142 ON CRYSTALLOGRAPHY. It t us rather wait with patience till future discoveries enable us to ire farther ; and satisfy ourselves in the mean time with ar- ranging those laws of affinity which have been ascertained, with, out deriding u liether it be the same force with gravitation, or a different one. [Thomson. CHAP. XI. ON CRYSTALLOGRAPHY. rri 1 HE word crystal (x/wof) originally signified ice; but it was afterwards applied by the ancients to crystallized silica, or rock crystal ; because, as Pliny informs us, they considered that body as nothing else than water congealed by the action of cold. Chemists afterwards applied the word to all transparent bodies of a regular shape; and at present it is employed to denote, in general, the regular h'gure which bodies assume when their particles have full liberty to combine according to the laws of cohesion. These regular bodies occur very frequently in the mineral kingdom, and have long attracted attention on account of their great beauty and regularity. By far the greater number of the salts as. sume likewise a crystalline form ; and as these substances are mostly soluble in water, we have it in our power to give the regu- lar shape of crystals in .some measure at pleasure. 1. Most solid bodies either occur in the state of crystals, or are capable of being made to assuma that form. Now it has long been observed by chemists and mineralogists, that there is a par. ticular form which every individual substance always affects when it crystallizes : this indeed is considered as one of the best marks fur distinguishing one substance from another. Thus common salt is observed to assume the shape of a cube, and alum that of oclahe. dron, consisting of two four-sided pyramids, applied base to base. Saltpetre affects the form of a six-sided prism ; and sulphate of magnesia that of a four-sided prism ; and carbonate of lime is of- ten found in the state of a rhomboid. Not that every individual substance always uniformly crystallizes in the same form ; for this ON CRYSTALLOGRAPHY. 143 is liable to considerable variations according to the circumstances of the case : but there are a certain number of forms peculiar to every substance, and the crystals of tliat substance, in every case, adopts one or other of these forms, and no other ; and thus com- mon salt, when crystallized, has always either the figure of a cube or octahedron, or some figure reducible to these. 2. As the particles of bodu s must be at liberty to move before they crystallize, it is obvious that we cannot reduce any bodies to the state of crystals, except those which we are able to make fluid. Now there are two ways of rendering the bodies fluid, namely, sol itioti in a liquid, and fusion by heat. These of course are the only methods of forming crystals in our power. Solution is the common method of crystallizing salts. They are dissolved in the water : the water is slowly evaporated, the saline particles gradually approach each other, combine together, and form small crystals ; which become constantly larger by the addi- tion of other particles, till at last they fall by their gravity to the bottom of the vessel. It ought to be remarked, however, that there are two kinds of solution, each of which presents different phenomena of crystallization. Some salts dissolve in very small pro- portions in cold water, but are very solable in hot water ; that is to say, water at the common temperature has little effect upon them, but water combined with caloric dissolves them readily. When hot water saturated with any of these salts cools, it be- comes incapable of holding them in solution : the consequence of which is, that the saline particles gradually approach each other and crystallize. Sulphate of soda is a salt of this kind. To crys- tallize such salts, nothing more is necessary than to saturate hot water with them, and set it by to cool. But were we to attempt to crystallize them by evaporating the hot water, we should not succeed ; nothing could be procured but a shapeless mass. Many of the salts which follow this law of crystallization combine with a great deal of water; or, which is the same thing, many crystals formed in this manner contain a great power of crystallization. There are other salts again which are nearly equally soluble in hot and cold water ; common salt for instance. It is evident that such salts cannot be crystallized by cooling; but they crystallize v«-ry well by evaporating their solution while hot. These salts generally contain but little water of crystallization. There are many substances, however, neither soluble in water OH CRYSTALLOGRAPHY. nor other liquids, which, notwithstanding, are capable of assuming a crystalline form. This is the case with the metals, with glass, and some other bodies. The method employed to crystallize them is fusion, which is a solution by means of caloric. By this method the particles are separated from one another ; and if the cooling goes on gradually, they are at liberty to arrange themselves in re- gular crystals. 3. To obtain large artificial crystals of a regular shape, requires considerable address and much patient attention. This curious branch of practical chemistry has been improved by Mr. Leblanc ; who has not only succeeded in obtaining regular crystals of almost any size at pleasure, but has made many interesting observations on crystallization in general*. His method is as follows : The salt to be crystallized is to be dissolved in water, and evaporated to such a consistency that it shall crystallize on cooling. Set it by, and when quite cold pour the liquid part off the mass of crystals at the bottom, and put it into a flat-bottomed vessel. Solitary crys- tals form at some distance from each other, and these may be ob. served gradually increasing. Pick out the most regular of these, and put them into a flat-bottomed vessel at some distance from each other, and pour over them a quantity of liquid obtained in the same way, by evaporating a solution of the salt, till it crystallizes on cooling. Alter the position of every crystal once at least every day with a glass rod, that all the faces may be alternately exposed to the action of the liquid ; for the face on which the crystal rests never receives any increment. By this process the crystals gradu. ally increase in size. When they have acquired such a magnitude that their form can easily be distinguished, the most regular are to be chosen, or those having the exact shape which we wish to obtain ; and each of them is to be put separately in a vessel filled with a portion of the same liquid, and turned in the same manner several times a- day. By this treatment they may be obtained of almost any size we think proper. After the crystal has continued in the liquid for a certain time, the quantity of salt held in solution becomes so much diminished, that the liquid begins to act upon the crystal and redissolve it. This action is first perceptible on the angles and edges of the crystal. They become blunted, and gra- dually lose their shape altogether. Whenever this begins to be • Jour, de Phys. lv. 300. ON CRYSTALLOGAPHY. 143 perceived, the liquid must bo pourod off, and a portion of new liquid put CRYSl A L LOCK A PHY. which makes them attract one part of another particle and repel the other parts. This polarity would e.xpluin the regularity of crystallization ; hot it is itself inexplicable. It is remarkable that crystals not only assume regular (i^u; but are always bounded by plane surfaces. It is very rarely in. deed that curve surfaces are observed in these bodies ; and when they are, the crystals always give unequivocal proofs of imperfec- tion. But this constant tendency towards plane surfaces is incon. ceivable, unless the particles of which the crystals are composed are themselves regular figures, and bounded by plane surfaces. 5. If the figure of crystals depends upon the figure of their in. tvgrant particles, and upon the manner in which they combine, it is reasonable to suppose that the same particles, wlu n at full liber. ty, will always combine in the same way, and consequently that the crystals of every particular body will be always the same. Nothing at first sight can appear farther from the truth than this. The different forms which the crystals of the same body assume are often very numerous, and exceedingly different from each other. Carbonate of lime, for instance, has been observed crystallized in no fewer than forty different forms, fluate of lime in eight differ, c-nt forms, and sulphate of lime in nearly an equal number. But this inconsistency is not so great as might at first sight ap- pear. Rome de Lisle has shewn that every body susceptible of crystallization has a particular form which it most frequently as. sumes, or at least to which it most frequently approaches. lierj;. man has demonstrated, that this primitive form, as Hauy has call- ed it, very often lies concealed in those very crystals which ap- pear to deviate farthest from it. And Hauy has demonstrated, that all crystals either have this primitive form, or at least contain it as a nucleus within them ; for it may be extracted out of all of them by a skilful mechanical division. These primitive forms must depend upon the figure of the inte- grant particles composing these crystals, and upon the manner in which they combine with each other. Now, by continuing the mechanical division of the crystal, by cut ing off slices parallel to each of its faces, we must at last reduce it to so small a size that it shall contain only a single integrant particle. Consequently this ultimate figure of the crystal must be the figure of the inte- grant particles of which it is composed. The mechanical division, , cannot be continued so far; but it may be continued till it ON CRYSTALLOGRAPHY. 147 can be demonstrated that no subsequent divi-ion can alter its fi- gure. Consequently it can be continued till the figure which it assumes is similar to that of its integrant particles. Hauy Ins found that the figure of the integrant particles of bodies, as far as experiment has gone, may be reduced to three ; namely, 1. The parallelepiped, the simplest of the solids, whose faces are six in number, and parallel two and two. 2. The triangular prism, the simplest of prisms. 3. The tetrahedron, the simplest of pyramids. Even this small number of primitive forms, if we consider the almost endless di- versity of size, proportion, and density, to which particles of diflVn-nt bodies, though they have the same figure, may still be liable, will be found fully sufficient to account for all the differ, ences in cohesion and heterogeneous affinity, without having re. course to dinVrent absolute forces. These integrant particles, when they unite to form the primitive crystals, do not always join together in the same way. Sometimes they unite by their faces, and at other times by their edges, leav- ing considerable vacuities between each. This explains why inte. grant particles, though they have the same form, may compose pri- mitive crystals of different figures. Mr. Hauy has ascertained that the primitive forms of crystals are six in number ; namely, 1. The parallelepiped, which includes the cube, the rhomboid, and all solids terminated by six faces, parallel two and two. 2. The regular tetrahedron. 3. The octahedron with triangular faces. 4. The six. sided prism. 5. The dodecahedron, terminated by rhombs. 6. The dodecahedron, with isosceles triangular faces. Each of these may be supposed to occur as the primitive form, or the nucleus in a variety of bodies ; but those only which are regu- lar, as the cube and the octahedron, have hitherto been found in any considerable number. But bodies, when crystallized, do not always appear in tht primitive form ; some of them indeed very seldom affect that form : and all of them have a certain latitude and a certain number of forms, which they assume occasionally as wellas the primitive form. 12 148 ON CRYSTALLOGRAPHY. Thus the primitive form of iluate of lime is the octalu dron ; but that salt is often found crystallized in cubes, in rhomboidal dude- cahedrons, and in other forms. All these different forms which a body assumes, the primitive excepted, have been denominated by Hauy secondary forms. Now what is the reason of this lati- tude in crystallizing ? why do bodies assume so often these se- condary forms ? 7. To this it may be answered : 1st, That these secondary forms are sometimes owing to varia- tions in the ingredients which compose the integrant particles of any particular body. Alum, for instance, crystallizes in octahe. drons 5 but when a quantity of alumina is added, it crystallizes in cubes ; and when there is an excess of alumina, it does not crys- tallize at all. If the proportion of alumina varies between that which produces octahedrons and what produces cubic crystals, the crystals become figures with fourteen sides ; six of which are parallel to those of the cube, and eight to those of the octahedron ; and according as the proportions approach nearer to those which form cubes or octahedrons, the crystals assume more or less of the form of cubes or octahedrons. What is still more, if a cubic crystal of alum be put into a solution that would afford octahedral crystals, it passes into an octahedron : and, on the other hand, an octahedral crystal put into a solution that would afford cubic crys- tals becomes itself a cube*. Now, how difficult a matter it is to proportion the different ingredients with absolute exactness must appear evident to all. 2d, The secondary forms are sometimes owing to the solvent in which the crystals are formed. Thus if common salt be dissolved in water, and then crystallized, it assumes the form of cubes ; but when crystallized in urine, it assumes the form, not of cubes, but of regular octahedrons. On the other hand, muriate of am. monia, when crystallized in water, assumes the octahedral form, but in urine it crystallizes in cubes +. 3d, But even when the solvent is the same, and the proportion of ingredients, as far as can be ascertained, exactly the same, still there are a variety of secondary forms which usually make their appearance. These secondary forms have been happily ex. * Leblanc, Ann. de Chim. xiv. 149. t Fourcroy aad Vauquelio, ibid, xiv, 149. NATURE OF THE DIAMOND. 149 plained by the theory of crystallization, for which we are indebted to the sagacity of Mr. Hauy ; a theory which, for its ingenuity, clearness, and importance, must ever rank high, and which must be considered as one of the greatest acquisitions which mineralo- gy, and even chemistry, have hitherto attained. According to this theory, the additional matter which envelopes the primitive nucleus consists of thin slices or layers of particles laid one above another upon the faces of that nucleus, and each layer decreasing in size, in consequence of the abstraction of one or more rows of integrant particles from its edges or angles. [Thomson. CHAP. XL ON THE NATURE OP THE DIAMOND. J. HE diamond is not more an object of attention to the jeweller or lapidary than to the chemist ; for it is as singular in its compo- sition among the crystals, as it is valuable, on account of its rarity and lustre, among the gems : having of late been fully ascertained to consist of nothing more than pure charcoal under a peculiar state of crystallization. Upon this subject we shall copy Mr. Smithson Tenant's interest, ing paper, as communicated to the Royal Society in 1797. Sir Isaac Newton having observed that inflammable bodies had a greater refraction, in proportion to their density, than other bodies, and that the diamond resembled them in this property, was induced to conjecture that the diamond itself was of an in. flammable nature. The inflammable substances which he employ, ed were camphire, oil of turpentine, oil of olives, and amber; these he called "fat, sulphureous, unctuous bodies;" and using the same expression respecting the diamond, he says, it is pro- bably " an unctuous body coagulated." This remarkable conjec- ture of Sir Isaac Newton has been since confirmed by repeated experiments. It was found, that though the diamond was capable of resisting the effects of a violent heat when the air was carefully excluded, yet that on being exposed to the action of heat and air, it might be entirely consumed. But as the sole object of these fcj 150 NATURE OF THE DIAMOND. expei'inn-nts was to ascertain the inflammable nature of the dia- mond, no attention was paid to the products afforded by its com- bustion j and it still therefore remained to be determined whether the diamond was a distinct substance, or one of the knoun in- flammable bodies. Nor was any attempt made to decide this question till M. Lavoisier, in 1772, undertook a series of PXJH ri- ments for this purpose. He exposed the diamond to the heat pro. duced by a large lens, and was thus enabled to burn it in close glass vessels. He observed that the air in which the inflammation had taken jtlace had become partly soluble in water, and pr< dpi. tated from lime-water a white powder which appeared to he ch-iik, being soluble in acids with effervescence. As M. Lavoisier seems to have had little doubt that this precipitation was occasioned by the production of fixed air, similar to that which is afforded by calcareous substances, he might, as we know at present, have in- ferred that the diamond contained charcoal ; but the relation be- tween that substance and fixed air, was then too imperfectly understood to justify this conclusion. Though he observed the resemblance of charcoal to the diamond, yet he thought that no- thing more could be reasonably deduced from their analogy, than that each of these substances belonged to the class of inflammable bodies. As the nature of the diamond is so extremely singular, it seemed deserving of further examination ; and it will appear from the following experiments, that it consists entirely of charcoal, differing from the usual state of that substance only by its crystal- lized form. From the extreme hardness of the diamond, a stronger degree of heat is required to inflame it, when exposed merely to air, than can easily be applied in close vessels, except by means of a strong burning lens ; but with nitre its combustion may be effected in a moderate heat. To expose it to the action of heated nitre free from extraneous matters, a tube of gold was procured, which by having one end closed might serve the purpose of a re- tort, a glass tube being adapted to the open end for collecting the air produced. To be certain that the gold vessel was perfectly closed, and that it did not contain any unperccived impurities which could occasion the production of fixed air, some nitre was heated in it till it had become alkaline, and afterwards dissolved out by water ; but the solution was perfectly free from fixed air, as it did not affect the transparency of lime-water. When the NATt RE OF THE. DIAMOND. 151 diamond was destroyed in the gold vessel by nitre, the substance which remained precipitated lime from lime-wat^r, and with acids afforded nitrous nnd fixed air; and it appeared solely to consist of nitre partly decomposed, and of aerated alkali. In order to estimate the quantity of fixed air which might be obtained from a given weight of diamonds, 2^ grs. of small ilia- inonds were weighed with great accuracy, and being put into the tube with £ oz. of nitre, were kept in a strong red heat for about an hour and a half. The heat being gradually increased, the nitre was in some degree rendered alkaline before the diamond began to be iiilhtiu'd, by which moans almost all the fixed air was re. tained by the alkali of the nitre. The air which came over was produced by the decomposition of the nitre, and contained so little fixed air as to occasion only a very slight precipitation from lime, water. After the tube had cooled, the alkaline matter contained in it was dissolved in water, and the whole of the diamonds were found to have been destroyed. As an acid would disengage nitrous air from this solution as well as the fixed air, the quantity of the latter could not in that manner be accurately determined. .To obviate this inconvenience, the fixed air was made to unite with calcareous earth, by pouring into the alkaline solution a sufficient quantity of a saturated solution of marble in marine acid. The vessel which contained them being closed, was left undisturbed till the precipitate had fallen to the bottom, the solution having been previously heated that it might subside more perfectly. The clear liquor being found, by means of lime-water, to be quite free from fixed air, was carefully poured oil' from the calcareous precipitate*. The vessel used on this occasion was a glass globe, having a tube annexed to it, that the quantity of the fixed air might b« more accurately measured. After as much quicksilver had been poured into the glass globe containing calcareous precipitate as was neces. nary to fill it, it was inverted in a vessel of the same fluid. Some marine acid being then made to pass up into it, the fixed air was expelled from the calcareous earth ; and in this experiment, in which 2{ grs. of diamonds had been employed, occupied the space * If much water had remained, a considerable portion of the fixed air would have beeo absorbed by it. But by the bom«* method as that described above, I observed, that as much fixed air might be obtained from a solution of mineral alkali, as by adding an acid to an equal quantity of the ume kind of alkali. — ORIC. fc4 152 NATURE OF THE DIAMOND. of a little more than 10. 1 oz. of water. The temperature of the room when the air was measured, was at 55", and the barometer stood at about 29.8 inches. From another experiment made in a similar manner with 1 gr. and a half of diamonds, the air obtained occupied the space of 6.18 oz. of water, according to which proportion the bulk of the fixed air from 2 and •£ gr. would have been equal to 10.3 oz. The quantity of fixed air thus produced by the diamond, does not differ much from that which, according to M. Lavoisier, might be obtained from an equal weight of charcoal. In the Memoirs of the French Academy of Sciences, for the year 1781, he has related the various experiments which he made to ascertain the proportion of charcoal and oxygen in fixed air. From those which he considered as most accurate, he concluded that 100 parts of fixed air contain nearly 28 parts of charcoal and 72 of oxygen. He estimates the weight of a cubic inch of fixed air, under the pressure and in the temperature above-mentioned, to be .695 parts of a grain. If we reduce the French weights and measures to English, and them compute how much fixed air, according to this proportion, 2} grs. of' charcoal would produce, we shall find that it ought to occupy very nearly the bulk of 10 oz. of water. M. Lavoisier seems to have thought that the aerial fluid produced by the combustion of the diamond was not so soluble in water as that procnred from calcareous substances. From its resemblance however, in various properties, hardly any douht could remain that it consisted of the same ingredients ; and I found, on com. Lining it with lime, and exposing it to heat with phosphorus, that it afforded charcoal in the same manner as any other calcareous substance. [Phil. Trans. 1797. Since the above account, M. Guyton de Morveau having burnt the diamond in oxygen gas, by the solar rays, and thereby obtained carbonic acid without residue, presumed that he had ascertained the diamond to consist of pure carbon, or the pure principle of charcoal, that which yields the pure acidifiable basis of the carbonic acid. But it was Clouet who proposed the con- clusive experiment of making soft iron pass to the state of steel, by cementation with the diamond. To this end he secured a dia- mond with some filings of iron, in a cavity bored in a block of soft iron, filling up the cavity with a stopper of iron. The MANUFACTURE OF GLASS. 153 whole properly inclosed in a crucible, was exposed to the heat of a blast furnace, by which the diamond disappeared, and the metal was fused, and converted into a small mass or bottom of cast steel. [Editor. CHAP. XII. MANUFACTURE OF GLASS. VJLASS is a strictly chemical substance, and well entitled to our attention as to its history, properties, and manufacture. SECTION I. History of the discovery. THE word glass is formed of the Latin glastum^ a plant, called by the Greeks, isatis ; by the Romans, vttrum ; by the ancient Briton?, guadum ; by the English, wood. We find frequent men- tion of this plant in ancient writers, particularly Caesar, Vitruvius, Pliny, Sic. who relate, that the ancient Britons painted or dyed their bodies with glastum, guadum, vitrum, &c. i. e. with the blue colour procured from this plant. And hence the factitious matter we are speaking of came to be called glass, as having always somewhat of this blueishness in it. At what time the art of glass-making was first invented is altogether uncertain. Some imagine it to have been invented be- fore the flood : but of this we have no direct proof, though there is no improbability in the supposition ; for we know, that it is al- most impossible to excite a very violent fin-, such as is necessary in metallurgic operations, without vitrifying part of the bricks or stones wherewith the furnace is built. This, indeed, might furnish the first hints of glass. making ; though it is also very probable, that such imperfect vitrifications would be observed a long time before people thought of making any use of them. The Egyptians boast, that this art was taught them by then great Hermes. Aristophanes, Aristotle, Alexander, Aphrodiseus, Lucretius, and St. John the divine, put it out of all doubt that MANUFACTURE OF GLASS. glass was used in their days. Pliny relates, that it was first dis- covered accidentally in S)ria, at the mouth of the river IMus, by certain merchants driven thither by a storm at sea ; who bfiii^ obliged to continue there, and dress their virtual* by making a fire on the ground, where there was great plenty of the herb kali ; that plant burning to ashes, its salts mixed and incorporated with the sand, or stones fit for vitrification, and thus produced glass ; and that, this accident being known, the people of Sidon in that tieighbourhood essayed the work, and brought glass into use ; since which time the art has been continually improving. Be this as it may, however, the first glass houses mentioned in history were erected in the city of Tyre, and here was the only staple of the manufacture for many ages. The sand which lay on the shore for about half a mile round the mouth of the river lielus was peculi. arly adapted to the making of glass, as being neat and glittering ; and the wide range of Tyrian commerce gave an ample vent for the productions of the furnace. Mr. Nixon, in his observations on a plate of glass found at Her- culaueum, which was destroyed A. D. 80, on which occasion Pliny lost his life, offers several probable conjectures as to the uses to which such plates might be applied. Such plates, he supposes, might serve for specula, or looking-glasses ; for Pliny, in speaking of Sidon, adds, Siquidem etiam specula excogitaverat : the reflec- tion of images from these ancient specula being effected by be. smearing them behind, or tinging them through with some dark co. lour. Another use in which they might be employed was for adorn, ing the walls of their apartments, by way of wainscot, to which Pliny is supposed to refer by his vitreae camerz, lib. xxxvi. cap. 25. s. 64. Mr. Nixon farther conjectures, that these glass plates might be used for windows, as well as the lamina of lapis specu. laris and phengites, which were improvements in luxury mention- ed by Seneca, and introduced in his time, Ep. xc. However, there is no positive authority relating to the using of glass-windows earlier than the close of the third century : Manifestius est (says Lactantius), mentem esse, quae per oculos ea quae sunt opposita, transpiciat, quasi per fenestras lucentc vitro aut specular! lapide obductas. The first time we hear of glass made among the Romans was in the reign of Tiberius, when Pliny relates that an artist had his house demolished for making glass malleable, or rather flexible ; MANUFACTURE OP CLASS. 155 though Petronius Arbiter and some others assure us, that the em. peroi ordered the artist to be beheaded for his invention. it appears, however, that before th*> conquest of Britain by the Romans, glass-houses had been erected in this island, as well as in Gaul, >|j;iin, and Italy. Hence in many parts of the country are to be found annulets of glass, having a narrow perforation and thick rim, denominated by the remaining Britons gleineu nai- s.reedh, or jilass adders, and which were probably iu former times used as annulets by the druids. It can scarcely be questioned that the Britons were sufficiently well versed in the manufacture of glass, to form out of it many more useful instruments than the glass beads. History indeed assures us, that they did manufac. ture a considerable quantity of glass vessels. These, like their annulvts, were most probably green, blue, yellow, or black, and many of them curiously streaked with other colours. The process in the manufacture would be nearly the same with that of the GauKs and Spaniards. The sand of their shores, being reduced to a sufficient degree of fineness by art, was mixed with three, fourths of its weight of their nitre (much the same with our kelp), and both were melted together. The metal was then poured into other vessels, where it was left to harden into a mass, and after, wards replaced in the furnace, where it became transparent in the boiling, and was afterwards figured by blowing or modelling in the lathe into such vessels as they wanted. It is not probable that the arrival of the Romans would improve the glass manufacture among the Britons. The taste of the Romans at that time was just the reverse of that of the inhabitants of thii island. The former preferred silver and gold to glass for the com- position of their drinking-vessels. They made, indeed, great im. provements in their own at Rome, during the government of Nero. The vessels then formed of this metal rivalled the bowls of porce- lain in their dearness, and equalled the cups of crystal in their clearness. But these were by far too costly for common use ; and therefore, in all probability, were never attempted in Britain. The glass commonly made use of by the Romans was of a quality greatly inferior ; and from the fragments which have been disco- vered, at the stations or towns of either, appear to have consisted of a thick, sometimes white, but mostly blue green metal. According to th«» venerable Bede, artificers skilled in making glass for windows were brought over into England in the year 674, MANUFACTURE OF CLASS. by abbot Benedict, who were employed in glazing the church and monastery of Weremouth. According to others, they were first brought over by Wilfrid, bishop of Worcester, about the same time. Till this time the art of making such glass was unknown in Britain ; though glass windows did not begin to be common be. fore the year 1180 : till this period they were very scarce in pri- vate houses, and considered as a kind of luxury, and as marks of great magnificence. Italy had them first j next Franoe, from whence they came into England. Venice for many years excelled all Europe in the fineness of its glasses ; and in the thirteenth century the Venetians were the only people that had the secret of making crystal looking-glasses. Tho great glass-works were at Muran, or Murano, a village near the city, which furnished all Europe with the finest and largest glasses. The glass manufacture was first begun in England in 1557 : the finer sort was made in the place called Crutched Friars, in Lon- don j the fine ilitit glass, little inferior to that of Venice, was first made in the Savoy-house, in the Strand, London. This manu- facture appears to have been much improved in 1635, when it was carried on with sea-coal or pit.coal instead of wood ; and a monopoly was granted to Sir Robert Mansell, who was allowed to import the fine Venetian Hint glasses for drinking, the art of making which was not brought to perfection before the reign of William III. But the first glass plates, for looking-glasses and coach-windows, were made in 1673, at Lambeth, by the encou- ragement of the Duke of Buckingham; who in 1670 introduced the manufacture of fine glass into England, by means of Venetian, artists, with amazing success. So that within a century past, the French and English have not only come up to, but even surpassed, the Venetians ; and we are now no longer supplied from abroad. The French made a considerable improvement in the art of glass, by the invention of a method of casting very large plates, till then unknown, and scarce practised yet by any but them, selves and the English. That court applied itself with a laudable industry to cultivate and improve the glass manufacture. A com- pany of glass-men was established by letters patent ; and it was provided by an arret, not only that the working in glass should not derogate any thing from nobility, but even that none but nobles should be allowed to work in it. An extensive manufactory of this elegant and valuable branch PROPERTIES OF GLASS. 157 of commerce was first established in Lancashire, about the year 1773, through the spirited exertions of a very respectable body of proprietors, who were incorporated by an act of parliament. From those various difficulties constantly attendant upon new un- dertakings, when they have to contend with powerful foreign establishments, it has not, however, been conducted with any great degree of success. SECTION II. Properties of Glass. THE properties of glass are highly interesting and remarkable. The following are among the most curious. 1. Glass is one of the most elastic bodies in nature. If the force with which glass balls strike each other be reckoned sixteen, that wherewith they recede by virtue of their elasticity will be nearly fifteen. 2. When glass is suddenly cooled, it becomes exceedingly brit- tle ; and this britfleness is sometimes attended with very surprising phenomena. Hollow bells made of annealed glass, with a small hole in them, will fly to pieces by the heat of the hand only, if the hole by which the internal and external air communicate be stopped with a finger. Lately, however, some vessels made of such annealed glass have been discovered, which have the remark, able property of resisting very hard strokes given from without, though they shiver to pieces by the shocks received from the fall of very light and minute bodies dropped into their cavities. These glasses may be made of any shape ; all that need be observed in making them is, that their bottom be thicker than their sides. The thicker the bottom is, the easier do the glasses break. One whose bottom is three fingers breadth in thickness flies with as much ease at least as the thinnest glass. Some of these vessels have been tried with strokes of a mallet sufficient to drive a nail into wood tolerably hard, and have held good without breaking. They have also resisted the shock of several heavy bodies let fall into their cavities, from the height of two or three feet ; as musket- balls, pieces of iron or other metal, pyrites, jasper, wood, bone, &c. But this is not surprising, as other glasses of the same shape and size will do the same : bnt the wonder is, that taking a shiver of flint of the size of a small pea, and letting it fall into the gla«s only from the height of three inches, in about two seconds the l.jS 1'HOVKRTIES OF GLASS. glass (lies, and sometimes at flic very moment of the shock: nay, a bit of Hint no larger than a grain dropped into several glasses successively, though it did not immediately break the' i. ycr wln-n set by, they all (lew in less than three quarters of an hour Some other bodies produce this effect as well as flint as sapphire, dia- mond, porcelain, hard tempered steel, also marbles MI ii as boys play with, and l'kewi->e pearls. Those experiments were made be. fore the Royal Society, and succeeded equally when the glasses were held in the hand, when they were rested on a pillow, put in water, or filled with water. It is also remarkable, Hut the glasses broke upon having im-ir bottoms slightly rubbed with the finger, though some of them did not fly till halt' an hour afUr the rubbing. If the glas-es are every where extremely thin, they do not break in these circumstances. Some have pret n-ied to account for these phaenomen,a, by say. ing, that the bodies dropped into the vessels cause a concussion which is stronger than the cohesive force of the iilass, and conse. quently that a rupture must ensue. But why does not a ball of iron, gold, silver, or copper, which are perhaps a thousand times heavier than flint, produce the same effect ? It is because they are not elastic. But surely iron is more elastic than the end of one's finger. Mr. Euler has endeavoured to account for these appear- ances from his principles of percussion. He thinks that this ex. periment entirely overthrows the opinion of those who measure the force of percussion by the. vis viva, or absolute apparent strength of the stroke. According to his principles, the great hardness and angular figure of the flint, which makes the space of contact with the glass extremely small, ought to cause an impres- sion on the glass vastly greater than lead, or any other metal ; and this may account for the flint's breaking the vessel, though the bullet, even falling from a considerable height, does no damage. Hollow cups made of green bottle-glass, some of them three inches thick at the bottom, were instantly broken by a shiver of flint, weighing about two grains, though they bad resisted the shock of a musket-ball from the height of three feet. That Mr. Luler's theory cannot be conclusive any more than the other, must appear evident from a very slight consideration. It is not by angular bodies alone that the glasses are broken. The marbles with which children play are round, and yet they have the came effect with the angular flint. Besides, if it was the mere PROPERTIES OF GLASS. 159 force of percussion which broke the glasses, undoubtedly the fracture would always take place at the very instant of the stroke; but we have seen, that this did not happen sometimes till a very considerable space of time had elapsed. It is evident, therefore, that this efl'ect is occasioned b) the putting in rnotioa some subtile fluid with which the substance of the glass is filled, and that the motions of this fluid, when once excited in a particular part of the glass, soon propagate themselves through the whole or greatest part of it, by which means the cohesive power becomes at last too weak to resist them. There can be little doubt that the fluid just now mentioned is that of electricity. It is known to exist in glass in very great quantity ; and it also is known to be capable of breaking glasses, even when annealed with the greatest care, if put into too violent a motion. Probably the cooling of glass hastily may make it more electric than is consistent with its cohesive power, so that it is broken by the least increase of motion in the electric fluid by friction or otherwise. This is evidently the case when it is broken by rubbing with the finger ; but why it should also break by the mere contact of flint and the other bodies abovementioned, has not yet been satisfactorily accounted for. A most remarkable phenomenon also is produced in glass tubes placed in certain circumstances. When these are laid before a fire in an horizontal position, having their extremities properly supported, they acquire a rotatory motion round their axis, and also a progressive motion towards the fire, even when their sup. ports are declining from the fire, so that the tubes will move a little way up hill towards the fire. When the tubes are placed in a nearly upright posture, leaning to the right hand, the motion will be from east to west; but if they lean to the left hand, their mo- tion will be from west to east ; and the nearer they are placed to the perfectly upright posture, the less will the motion be either way. If the tube is placed horizontally on a glass plane, the frag- ment, for instance, of coach window-glass, instead of moving to- wards the fire, it will move from it, and about its axis in a con. trary direction to what it had done before; nay, it will recede from the fire, and move a little up hill when the plane inclines towards the fire. These experiments are recorded in the Philoso- phical Transactions. They succeeded best with tubes about twenty or twenty.two inches long, which had in each end » pretty strong pin fixed in cork for an axis. 160 PROPERTIES OF GLASS. The reason given for these phenomena is the swelling of the tubes towards the fire by the heat, which is known to expand all bodies. For, say the adopters of this hypothesis, granting the ex- istence of such a swelling, gravity must pull the tube down when supported near its extremities ; and a fresh part being exposed to the fire, it must also swell out and fall down, and so on. Unf, without going farther in the explanation of this hypothesis, it may be here remarked, that the fundamental principle on which it proceeds is false: for though fire indeed makes bodies expand, it does not increase them in weight ; and therefore the sides of the tube, though one of them is expanded by the fire, must still re. main in equilibrio ; and hence we must conclude, that the cause of these phaenomena remains yet to be discovered. 4. Glass is less dilatable by heat than metalline substances ; and solid glass sticks are less dilatable than tubes. This was first dis. covered by Colonel Roy*, in making experiments in order to re- duce barometers to a greater degree of exactness than hath hitherto been found practicable ; and since his experiments were made, one of the tubes eighteen inches long, being compared with a solid glass rod of the same length, the former was found by a pyrometer to ex- pand four times as much as the other, in a heat approaching to that of boiling oil. On account of the general quality which glass has of expanding less than metal, M. de Luc recommends it to be used in pendulums: and, he says, it has also this good quality, that its ex- pansions are always equable and proportioned to the degrees of heat ; a quality which is not to be found in any other substance yet known. 5. Glass appears to be more fit for the condensation of vapours than metallic substances. An open glass filled with water, in the •ummer time, will gather drops of water on the outside, just as far as the water in the inside reaches ; and a person's breath blown on it manifestly moistens it. Glass also becomes moist with dew, when metals do not. 6. A drinking.glass partly filled with water, and rubbed on the brim with a wet finger, yields musical notes, higher or lower as the glass is more or less full, and will make the liquor frisk and leap about. 7. Glass is possessed of extraordinary electrical virtues. • Phil. Trans, vol. Uxii. p. 608. MANUFACTURE OF GLASS. l6l SFCT1ON III. Manufacture of Glass. Drinking, Watch , Windois, and Plate.Glass. Glass is a combination of sand, flint, spar, or some other sili. ceous substances, with one or other of the fixed alkalies, and in some cases with a metallic oxyd. Of the alkalies, soda is com- monly preferred : and of the siliceous substances, white sand is roost in repute at present, as it requires no preparation for coarse goods, while mere washing in wat--r is sufficient for those of a finer quality. The metallic oxyd usually employed is litharge, or some other preparation of lead, as being the cheapest metal we can have recourse to. It is also necessary that the siliceous matter should be fused in contact with something called a flux. The substances proper for this purpose are lead, borax, arsenic, nitre, or any alkaline matter. The lead is used in the state of red-lead ; and the alkalies are soda, pearl-ashes, sea-salt, and wood-ashes. When red-lead is used alone, it gives the glass a yellow cast, and requires the addition of nitre to correct it. Arsenic, in the same manner, if used in excess, is apt to render the glass milky. For a perfectly transparent glass, the pearl. ashes are found much superior to lead ; perhaps better than any other flax, except it be borax, which is too expen. sive to be used, except for experiments, or for the best looking, glasses. The materials for making glass must first be reduced to powder, which is done in mortars or by horse-mills. After sifting out the coarse parts, the proper proportions of silex and flux are mixed together and put into the calcining furnace, where they are kept in a moderate heat for five or six hours, being frequently stirred about during the process. When taken out, the matter is called frit. Frit is easily converted into glass by only pounding it, and vitrify, ing it in the melting pots of the glass furnace : but in making fine glass, it will sometimes require a small addition of flux to the frit to correct any fault. For, as the flux is the most expensive article, tlie manufacturer will rather put too little at first than otherwise, as he can remedy this defect in the melting pot. The heat in the furnace must be kept up until the glass is brought to a state of per. VOL. VI. Id 162 MANUFACTURE OF GLASS. feet fusion ; and dining this process any scum which arises must be removed by ladles. NVhen the glass is perfectly melted, the glass blowers commence their operations. The following compositions of the ingredients for glass are ex. tracted from the Handmaid to the Arts : " For the best Hint-glass, 120lbs. of white sand, oOlbs. of red lead, 40ll>s. of the best pearl. ashes, 20lbs. of nitre, and five ounces of magnesia ; if a pound or two of arsenic be added, the composi- tion uili fuse much quicker, and with a lower temperature. " For a cheaper flint-glass, 120lbs. of white sand, 35lbs. of pearl-ashes, 40lbs. of red-lead, 13lbs. of nitre, six pounds of arsenic, and four ounces of magnesia. " This requires a long heating to make clear glass ; and the heat should be brought on gradually, or the arsenic is in danger of subliming be-fore the fusion commences. A still cheaper compo- sition is made by omi ting the arsenic in the foregoing, and sub- stituting common sea. salt. " For the best German crystal glass, 120lbs. of calcined flints or white sand, the best pearl-ashes 70lbs., saltpetre lOlbs., arsenic half a pound, and five ounces of magnesia. Or, a cheaper com. position for the same purpose is, 1201bs. of sand or flints, 46'lbs. of pearl-ashes, seven pounds of nitre, six pounds of arsenic, and five ounces of magnesia. This will require a long continuance in the furnace ; as do all others where much of the arsenic is employed. " For looking-glass plates, washed white sand, GOlbs., purified pearl-ashes 25lbs., nitre I5lbs., and seven pounds of borax. If properly managed, this glass will be colourless. But if it should be tinged by accident, a trifling quantity of arsenic, and an equal quantity of magnesia, will correct it; an ounce of each may be tried first, and tt»e quantity increased if necessary. *' The ingredients for the best crown-glass must be prepared in the same manner as for looking-glasses, and mixed in the following proportions : 6oibs. of white sand, 301bs. of pearl-ashes, and 15lbs. of nitre, borax a pound, and half a pound of arsenic. ** The composition for common green window glass is 120lbs. of white sand, SOlbs. of unpurified pearl-ashes, wood-ashes well burnt and sifted, GOlbs., common salt 20lbs., and five pounds of arsenic. " Common green bottle-glass is made from 200lbs. of wood- ashes, and JOOlbs. of sand; or IfOlbs. of ashes, lOOlbs. of saud, AlANLFACTURE OF GLASS. 163 And jOlbs. of the lava of an iron-furnace: these materials must be well mixed." The materials employed in the manufactory of glass are by che- mists reduced to three classes, namely, alkalies, earths, and me. tallic oxides. The fixed alkalies maybe employed indifferently ; but soda is preferred in this country. The soda of commerce is usually mixed with common salt, and combined with carbonic acid. It is proper to purify it from both of these foreign bodies before using it. This, however, is seldom done. The earths are silicia, (the basis of flints), lime, and sometimes a little alumina, (the basis of clay). Silicia constitutes the basis of glass. It is employed in the state of fine sands or flints; and sometimes, for making very fine glass, rock crystal is employed. When sand is used, it ought if possible to be perfectly white ; for when it is coloured with metallic oxides, the transparency of the glass is injured. Such sand can only be employed for very coarse glasses. It is necessary to free the sand from all the lo:«>e earthy particles with which it may be mixed, which is done by washing it well with water. Lime renders glass less brittle, and enables it to withstand better the action of the atmosphere. It ought in no case to exceed the twentieth part of the silicia employed, otherwise it corrodes the glass pots. This indeed may be prevented by throwing a little clay into the melted glass ; but in that case a green glass only is ob. tained. The metallic oxyds employed are the red oxyd of lead or litharge, and the white oxyd of arsenic. The red oxyd of lead, when added in sufficient quantity, enters into fusion with silicia, and forms a glass without the addition of any other ingredient. Five parts of minium and two of silicia form a glass of an orange. colour and full t»f striae. Its specific gravity is five. The red oxyd of lead ren- ders glass less brittle and more fusible ; but, when added beyond a certain proportion, it injures the transparency and the whiteness of the glass. The white oxyd of arsenic answers the same purposes with that of lead ; but on account of its poisonous qualities it is seldom used. It is cuftomary to add a little nitre to the white oxyd of arsenic, to prevent the heat from reviving it, and rendering it volatile. When added beyond a certain proportion, it reader* glass opaque and M 2 164 MANUFACTURE OF GLASS. milky like the dial-plate of a watch. When any combustible body is present, it is usual in some manufactures to add a little white oxyd of arsenic. This supplying oxygen, the combustible is burnt) and Hies off; while the revived arsenic is at the same time vola. tilized. There are several kinds of glass adapted to different uses. The best and most beautiful are the flint and the plate glass. These, when well made, are perfectly transparent and colourless, heavy and brilliant. They are composed of fixed alkali, pure siliceous sand, calcined Hints, and litharge, in different proportions. The Hint-glass contains a large quantity of oxyd of lead, which by cer- tain processes is easily separated. The plate-glass is poured in the melted state upon a table covered with copper. The plate is cast half an inch thick, or more, and is ground down to a proper degree of thinness, and then polished. Crown.glass, that used for windows, is made without lead, chiefly of fixed alkali fused with silicious sand, to which is added some black oxyd of manganese, which is apt to give the glass a tinge of purple. Bottle. glass is the coarsest and cheapest kind : into this little or no fixed alkali enters the composition. It consists of an alkaline earth combined with alumina and silica. In this country it is composed of sand and the refuse of the soap boiler, which consists of the lime employed in rendering his alkali caustic, and of the earthy matters with which the alkali was contaminated. The most fusible is flint glass, and the least fusible is bottle glass. Flint-glass melts at the temperature of 10° Wedgewood ; crown- glass at 30° ; and bottle.glass at 47°. The specific gravity varies between 2'4S and 3 '3 8. Glass is often tinged of various colours by mixing with it, while in fusion, some one or other of the metallic oxyds; and on this process, well conducted depends the formation of pastes or facti- tious gems. Blue glass is formed by means of oxyd of cobalt. Green, by the oxyd of iron or of copper. Violet, by oxyd of manganese. Red, by a mixture of the oxyds of copper and iron. Purple, by the purple oxyd of gold. "White, by the oxyd of arsenic and of zinc. Yellow, by the oxyd of silver and by combustible bodie?, GLASS-BLOWING. 165 Opticians, who employ glass for optical instruments, often com- plain of the many defect! under which it labours. The chief of these are the following : .S freaks. — These are waved lines, often visible in glass, which interrupt distinct Vision. They are probably owing sometimes to want of complete fusion, which prevents the different materials from combining sufficiently ; but in some cases also they may be produced by the workmen lifting up, at two different times, the glass which is to go to the formation of one vessel or instrument. Tears. — These are white specks or knots, occasioned by the vi- trified clay of the furnaces, or by the presence of some foreign salt. Bubbles.— These are air.bubbles which have not been allowed to escape. They indicate want of complete fusion, either from too little alkali, or the application of too little heat. Cords. — These are the asperities on the surface of the glass, in consequence of too little heat. Glass-blowing. The art of forming vessels of glass is termed blowing, from its being in agreat measure performed by the operator blowing through an iron tube, and by that means inflating a piece of glass which is heated so as to become soft and exceedingly pliable. By a series of the most simple and dexterous operations, this beautiful mate- rial is wrought into the various utensils of elegance and utility, by methods which require bat very few tools, and those of the most simple construction. Watch-glasses are made by first blowing a hollow globe, the proper radius for the glasses ; then by touching it with an iron ring. This cracks out a watch.glass in an instant. The same globe will make several glasses. Window or table-glass is worked nearly in the same manner : the workman blows and manages the metal, s>o that it extends two or three feet in a cylindrical form. It is then carried to the fire, and the operation of blowing repeated till the metal is stretched to the dimensions required, the side to which the pipe is fixed diminishing gradually till it ends in a pyramidal form ; but, in order to bring both ends nearly to the same diameter, while the glass continues flexible, a small portion of hot metal is added to the pipe ; the whole is drawn out with a pair of iron pincers, and the same end is cat off with a little cold water as above. M 3 165 RUPERT'S DROP$. The cylinder thus open at one end is returned to the mouth of the furnace, win-re it is cut by the aid of cold water, and ripped up through its whole length by a pair of iron shears ; after which it is gradually heated on an earthern table, in order to unfold its length, •while the workman with another iron tool alternately raises and depresses the two halves of the cylinder: by which process, the one half accommodates itself to the same flat form as the other. Plate-glass is the last and most valuable kind, and is thus called from its being cast in plates or large sheets: it is almost exclusively employed for mirrors or looking-glasses, and for the windows of carriages. Plate.glass was formerly blown ; but that, method having been found very inconvenient, casting was invented ; namely, the liquid metal is conveyed from the furnace to a large table, on which it is poured, and all excrescences, or bubble?, are immediately re- moved by a roller that is swiftly passed over it. It is then an. nealed iu the manner already referred to. SECTION IV. Rupert's Drops. liatarian Tears. Bolognian Phial. THESE are peculiar modifications of glass, for the purpose of de.. ception or amusement. Rupert's Drops, an elegant glass toy, are simply formed by pouring a small solid lump of green bottle glass, when red-hot, into water, by which means the rounded lump assumes gradually a lengthened form, terminating with a fine and nearly capillary tail, at the e.x- tn inity. This solid lump will bear very considerable violence on the massy end without injury, and is altogether extremely tou^h ; but whenever the smallest portion of the thinner end is broken olf, the whole bursts with a smart snap, and instantly crumbles into innumerable fragments as small as fine sand ; which, from their yery oionteDett, and ,?' imperfection of their crystallization, do no other injury to the hand that holds the drop, than that of pro. during a slight sting from the suddt n concussion. This curious and i xtraordinary fragility is obviously owing to gome p< rmanent and very strong inequality of pressure ; for when the Huprrt's drops are heated so red as to be soft, and are let to cool gradually of themselves, and, consequently, to become better annealed, this | ru| eriy of bursting is entirely lost, and, at the same time, the specific gravity of the drop is increased. RUPERT'S DROPS. 167 These drops are also called, on the continent, Larmes Batavi. ques, or Hatavian Tears. All glass, not regularly annealed, or, in other words, cooled suddenly instead of progressively, has a tendency towards the same frangibility. Thus, in common window glass, if it be properly annealed, the diamond cuts it with moderate ease, making an uni- form smooth furrow, at first dark, but gradually opening, and appearing like a bright silver thread : but when the glass is badly annealed, the diamond works with much more difficulty, the cut opens very slowly, and often flies into a different direction, or the glass entirely breaks. There is another equally curious glass toy, formed upon the same principle, and evincing the same ellect, called the Bologna phial. This is simply a phial, of any shape whatever, made of any kind of glass, but much thicker at the bottom than at top, and cooled immediately, without annealing. These -being pretty stout, from their thickness will bear a smart blow from a wooden mallet, or any blunt instrument, or the concussion of a leaden bullet drop, ped from a considerable height, without injury : but if any sharp body, howevi r small, such as a large grain of sand, or which is still better, the shiver of a gun. flint, be dropped in from only a few inches height, the bottom cracks all around, just above the thickest part, and drops off. The same effect takes place, if the bottom be slightly scratched with any hard body. When very brittle, if a hard angular substance, as a cut diamond, be dropt in, it will sometimes pass through the bottom, though very thick, with apparently as little resistance as through a spider's web. These glasses, when they have received the first injury, do not always crack immediately, but remain whole, sometimes for a few minutes, sometimes for hours, and then suddenly give way. [Pantologia, Aikin'sChem. Diet. C 168 ] CHAP. XIII. GUNPOWDER. SECTION I. Of the time when gunpowder waijftrst discovered. A HE history of the discovery of gunpowder is involved in much obscurity ; the most ancient authors differing from each other in their accounts of this matter, and many of them confounding two distinct inquiries ; the discovery of the composition of gunpowder; and the discovery of the means of applying it to the purposes of war. Father Kircher* affirms, that without controversy we ought to attribute the invention of gunpowder to Barthold Schwartz, or Barthold the black, a monk of Goslar in Germany, and a profound alchemist. This man having mixed together, with a medical view, nitre, sulphur, and charcoal, a spark accidentally fell upon the mixture, blew up the pot in which it was contained, and caused a dreadful explosion. The monk, astonished at the event, made se. veral repetitions of his experiment, and thereby fully discovered the n^"re of cunpowder, in the year 1354- Kircher gives us also, out ( : i very old German book which he professes to have read, a monkish account of the first use which Schwartz maue of his gun- powder ; he employed it to frighten some robbers from their haunts in the woods. Sebastian Munster says, that he was well informed by a very eminent physician, that the Danes used guns in naval engagements in the year 1354, and that a chemist, called Schwartz, was the first inventor of them +. Pontanus, the Danish historian, accedes to this opinion. Polydore Virgil, who died in the year 1555, attributes the dis- » Kirch. Mun. Sub. p. 487. •f Achilles Gassaruf, medicinae doctor, ft histori«?raphus, diligcntissirae •<- rip-it inihi, Bom hard as 311110 Christ! 1354, in usu apud mare Danicum fuisse, priinumque invpntorctn ct autorem cxtitisse chymistam quondam nomine Bar- t 'loldum Schwartzum monacbum. Munster. Coranogr. Univ. Lib. 3. C. 174, GUNPOWDER. covery of gunpowder to some very ignoble German, whose name he wishes might never be handed down to postf rity. He further informs us, that this German invented also an iron tube, and taught the Venetians the use of guns, in the year 1380*. This is the common account of the discovery of gunpowder ; its truth however is rendered doubtful by what follows. The battle of Cressy was fought in the year 1346 ; and an his. torian who lived at that time is quoted by Spondanus as affirming, that the English greatly increased the confusion the French had been thrown into, by discharging upon them from their cannon hot iron bullets t. Three years before the battle of Cressy, the Moors were besieged by the Spaniards in the city of Algeziras ; and we learn from Mariana, the Spanish h'storian, " that the besieged did great harm among the Christia.is with iron bullets they shot :" the same author adds, " this is the first time we fi:H any mention of gunpowder and ball in our histories |." The Eirls of Derby and Salisbury are mentioned by Mariana as having assisted at the siege of Algeziras ; and as they returned to England in the latter end of the year 1343, it is not an improbable conjee turp, t': at- having been witnesses of the havock occasioned by the Moorish Ui>--arms, they brought the secret from Spain to England, and introduced the use of artillery into the English army at the battle of Cressy. Tlie use of guns in Spain in the year 1343, is proof sufficient ei'her that Schwartz was not the inventor of gunpowder, or that Kircher and others are mistaken in fixing his discovery so late as the year 1354. There is reason, however, to believe, that both gunpowder and guns were known in Germany at least forty years before the period assigned by the Spanish historian for their first introduction into Spain. In the armory at Amberg, in the Palatinate of bavaria, there is a piece of ordnance, on which is inscribed the year 1303 §. This is the earliest account I have yet met w i.h of the certain use of gunpowder in war ; and it seems probable en .ugh, as the Pope * Polyd. Virg. de Inven. Rcrum, Lib. II. C. XI. •f Spond. Ann. Eccl. ann. 1346. J Mariana'-. FIM. of Spain, l.n°;. Trans. ^ Quarn opinionrm (of Schwartz being the inventor of gunpowder) generalis- simos Stettrnius refutat, cum ex eo quod Ambergtr Pnlatinalus Suprrioris in officina armorum roprriatur tormcutum militarc, cui sit aunus 1303 in»ori»tu>. Acta Li ud. 1769, p. 19. 170 GUNPOWDER. and the Duke of Bavaria are thought to have been the first princes who made saltpetre in Europe*. It ought not to he concealed from the reader, that Camerarius quotes a Danish historian, as relating that Christopher, king of the Danes, was killed in battle by the stroke of a gun, in the I280r. Upon examining the passage quoted by Camerarius J, it is only said, that Christopher, the son of King Wajdemar, was killed in the beginning of an engagement by a gun, a warlike instrument then lately discovered. Now it appears §, that NValdemar, Christopher's father, did notsucceed to tin- crown of Denmark till the y«iar 1332, and that his son was killed in a naval engagement several years afterwards)!, probably about the time assigned by Munster for the first use of gunpowder in Denmark. But we are able, upon good grounds, to carry the discovery of gunpowder to a period antecedent to the date of the Amberg piece of ordnance ; and it is probable enough, that its composition was known long before we read any thing of its use in war. Roger Bacon died at Oxford in 1292. In the printed copies of the works of this renowned Monk, there are two or three passages, from which it may fairly be inferred, thnt he knew the compo. sition of gunpowder1[ ; and a manuscript copy is said to have been seen**, wherein saltpetre, sulphur, and charcoal, are expressly mentioned, as the ingredients of a composition which would burn at any distance. But though it be allowed, that Bacon was well acquainted with the composit'on of gunpowder, it will not follow, either that he was the first discoverer of it, or that he knew its ap- plication to fire-arms. • Clarke's Nat. His. of Saltpetre. •f Cranzius scribit Christophormn Dannrum re^om in praelio bombard ac ictij occisum anno 12bO. Camera, ilor. Subs. foil. p. 3. 312. J Cranzius Vandal. Lib. VIII. C. 23. () Cranzins Daniae Lib. VII. C. 32. (I Id. Lib. VII. C. 38. f In oinnom disiantiam qnam volumu?, possumus nrlificialiter componcrc ignem comburcntem ex sale petraj ct alii;- It. Bacon de Mirab. Potes. ArtN ct Naturae, Epis. C. VI. — sod lumen viliis pctra Luru v»po vir can utriei siilphu- risetbic fades (onilrum ct coru-c:itionem,si ?cias artificiuin. Id. ib. C. XI- It is very probable, that in the first <>: thr-e passages, Baron, concealed sulphur and charcoal under the word alii-; :ind (hat in the last, having mentioned saltpetre and sulphur, he concealed charcoal and the method of mixing the three ingre- dients, under the barbarous terms, Lnru vopo vir can utriet. ' * • Plott'i Nat. His. of Oxfordkhire. GUNPOWDER. 171 The Moors, we hare seen, who had settled in Spain, arc esteem, ed by some to have been the first persons who used gunpowdrr in the practice of war ; they also brought into Europe a great many Arabian books, and introduced a taste for chemistry into different countries, about the time in which Bacon nourished. It is con. fessed, on all hands, that Bacon was no stranger to Arabian litera- ture ; a great part of his optical disquisitions, being evidently borrowed from Alhazen (he Arab ; and it is not a supposition wholly void of probability, that he derived his knowledge of the composition of gunpowder from the same source. As to his know, ledge of the use of it in war, he certainly had some idea of it; for he intimates, that cities and armies might be destroyed by it iu various ways : but it is not equally certain that he had any specific notion of the manner of using gunpowder, which unquestionably prevailed soon after his death. It is one thing to throw out a conjecture concerning the effects which might be produced by the proper ^plication of a known substance ; another, to describe the means of applying it. There are substances in nature, from a combination of which it is possible to destroy a ship, or a citadel, or an army, by a shower of liquid fire spontaneously lighted in the air ; every person who is aware of the dreadful fiery explosion which attends the mixture of two or three quarts of spirit of turpentine with strong acid of nitre, must acknowledge the tru h of the assertion ; but the simple knowledge of the possibility of effecting such a destruction, is a very different matter from the knowledge of its practicability ; though future ages may, perhaps, invent as many different ways of making these sub. stances unite in the air, so as to fall down in drops of fire, as hare been invented of making gunpowder a sa instrument of the des- truction of our species since the time of Bacon. From the accounts given of the attempts of Salmoneus and Cali- gula to imitate thunder and lightning, some have been of opinion that gunpowder was known to the ancients* ; be that as it may, we cannot hesitate in admitting that it has been long known in vari. ous parts of Asia. It would be useless to cite a variety of autho. rities in proof of this point ; 1 will content myself with that of Lord Bacon : — " Certain it is, that ordnance was known in the city of • S*-e Dotens' Enquiry into the Ducoveriet of the Modern*, p. 263. English 172 GUNPOWDEK. the Oxidrakes in India ; and was that which the Macedonians called thunder and lightning, and magick. And it is well known that the use of ordnance hath been in China above 2000 years*." One of the most useful applications of gunpowder, is in the art of mining. The hammer and metallic wedges were probably the first instruments which men used for the splitting of rocks. The appli- cation of wooden wedges to the same purpose, seems to have been a more recent discovery : it is the property of dry wood to expand itself, when wetted with water: miners have had ingenuity enough to avail themselves of this property, for it is a practice with them to drive wedges of dry wood into the natural or artificial crevices of rocks, and to moisten the M'edges with water. Wood, by imbibing moisture, swells in every dimension ; and the force of this expansion is sufficient, in many cases, to detach large pieces from the main body of a rock. But the expansive force of gunpowder is incomparably greater than that of moistened wood. There are different accounts of the time when gunpowder was first applied to the blasting of rocks. Rossler relates that in 1627, the blasting of mines was brought from Hungary, and introduced in the Ger- man mines : but Bayer says, that in 1613, it was invented by Martin Freygold, at Freiberg +. In answer to an inquiry which I made concerning the time when blasting was introduced at the famous copper-mine at Ecton in Staffordshire, I received the following account from a very able and intelligent person. *' I can give you a little better information concerning the affair of blasting. I have known that country where the mine is, above fifty years; and have often seen the smith's shop in which, tradition says, the first boring auger that had ever been used in England was made ; and that the first shot that was ever fired in Derbyshire or Staffordshire, was fired in this very copper, mine at Ecton. The inhabitants of Wetton (a village adjoining to the mine) tell me the auger was made by some German miners, sent for over by Prince Rupert to work this copper mine at Ecton. The Prince (Rapin says) came into England in 1636, and was ordered by the king to leave the kingdom 164-5 ; and though he was afterwards admiral under Charles the Second, it is most pro- bable the miners came during his first abode in this kingdom. I am * Bacon's Essay on the Vicissitude of Things. i See Travels through the Bannat, &c. by Baron Born, F.ng. Trans, p. 19?. GUNPOWDER, 173 very well convinced of the truth of the above tradition, because the fathers of my informers might be very well acquainted with the mincries that introduced blasting among them." In addition to this account I would observe, that the manner of splitting rocks by gunpowder, as practised at Liege, was published by the Royal Society, in 1665 ; and that it was not till about the year l6'84, that the miners in Somersetshire began to use gunpowder*. In the year 1668 Prince Rupert was chosen governor of the Society for the Mines Royal + ; and as he lived fourteen years after that appoint, ment, it is not improbable that he might send for the German miners in consequence of his connection with that society. Before the discovery of blasting rocks by gunpowder, it was the custom in our English mines, as well as in Germany, to split them by wood fires. This method is minutely described by Agricola+, and it is not yet wholly fallen into disuse §. It is a very ancient mode of mining, being mentioned by Diodorus Siculus, as practised in some Egyptian mines|| : he gives us, in the place here referred to, such a melancholy account of the condition of the poor slaves who were employed in those mines, as must make the heart of every humane man, who has a rational respect for the natural rights of every individual of our species, swell with indignation, and thrill with horror. Would to God, that the clemency of the task- masters in the mines of Peru, and in other settlements of European Christians, could induce us to believe that Diodorus Siculus had exaggerated the barbarity of Heathen policy ! But there is much to be done, much, I fear, to be suffered, by all the states of Christen, dom, before the Gospel of Christ can be said to be established amongst them as a rule of life influencing their conduct. It is related of Hannibal, that he opened himself a passage through the Alps, by applying fire and vinegar to the rocks which opposed his route. This mode of splitting rocks was, probably, not invented by Hannibal ; he might have had frequent opportu- nities of observing a similar practice in the silver mines in Spain, which daily afforded him three hundred pounds weight of silver ft * Philos. Trans. t Account of Mines, p. 20. £ De Re Metal. § Philos. Trans. 1777, p. 414. || Lib. III. 1 Minim ad hue per Hispanias ab Hannibale inchoatos puteos durare, siia ah inventoribus noinina habentes. Ex qneis Bebulonppellaturhodieque, qui CCC pondo Hannibali subninUterabat indies ! Plin. Hist. Nat. L. 33. s. 31 , 174 COMPOSITION AND ANALYSIS OF GUNPOWDER. There is nothing, indeed, said of vinegar in the description of the ptian mines before mentioned : but Pliny expressly affirm?, that it was the quality of vinegar, when poured upon rock?, to split such as an antecedent fire had not split ; and that it was the custom of miners to burst the rocks they met with, by fire and vinegar*. This account of Hannibal's using vinegar in splitting the rocks, is generally looked upon as fabulous: for my part, I can easily con. ceiye, that a few barrels of vinegar might have been ofgn-at use, if the ro; ks were of the limestone kind 5 aud, whether they were so or not, I leave to be settled by those, who have visited the place where this famous attempt was made. Vinegar corrodes all sorts of lime- stone and marble rocks ; and hence, being introduced into the crack made by the fire, it might be very efficacious in widening them, and rendering the separation of large lumps by iron crows and wedges more easy. It is erroneously supposed, that a large quantity of viuegar was requisite, for the vinegar did not reduce the whole mass of rocks into a pulp ; since Livy clearly informs us, that after the action of both the fire and vinegar, they were obliged to open their passage by iron instruments, which would have been •wholly unnecessary, had the main body of the rocks been dissolved by the vinegar i. SECTION II. Composition and Analysis of Gunpowder. GUNPOWDER is an artificial composition, consisting of saltpetre, sulphur, and charcoal. The principal things to be respected in the making of gunpowder are, the goodness of the ingredients ; the manner of mixing them ; the proportion in which they are to Le combined ; and the drying of the powder after it is made. Saltpetre, in its crude state, whether it be brought from the East Indies, or made in Europe, is generally, if not universally, mixed with a greater or less portion of common salt : now a small por- tion of common salt injures the goodness of a large quantity of gunpowder; hence it becomes nece-sary, in making gunpowder, to use the very finest saltpetre. The purest sulphur is that which * Sata rutnpit infusum (acetum) qcte non ruperit ignis antec<-dcns. PJin. Nat. Hist. L- 23. s. 27. & L. 33. s,21. where by Silicea cannot be understood what we call flint-, since vinegar ha» no action on flints. t — ardentiaqor saxa infuso nrrto putrrfaciunt. Ita torridam incrndto rupem frrro pandunt. Liv. Hist. I. xxi. c. xzxvii. COMPOSITION AND ANALYSIS OP GUNPOWDER. 173 is sold in shops under the name of flowers of sulphur ; but the roll sulphur being much cheaper than the flowers of sulphur, and being also of a great degree of purity, it is the only sort which is used in the manufacturing of gunpowder. With relation to the charcoal, it has been generally believed that the coal from soft and light woods was better adapted to the making of gunpowder, than that from the hard and heavy ones : thus Evelyn says of the hazel, that ** it makes one of the best coals used for gunpowder, being very fine and ligtit, till they found alder to be more fit*." And in another place he thinks that lime-tree coal is still better than that from alder f. An eminent French chemist has shewn, from actual ex- periment, that this opinion in favour of coal from light woods is ill founded; he affirms, that powder made from lime-tree coal, or even, from the coal of the pith of alder-tree, is in no respect preferable to that made from the coal of the hardest woods, such as guaiacum and oak J. '1 his remark, if it l;<> confirmed by future experience, may be of no small use to the makers of gunpowder; as it is not always an easy matter for ihem to procure a sufficient quantity of the coal of soft wood. The mixture of the materials of which gunpowder is made, should be as intimate and as uniform a» possible ; for, in whatever manner the explosion may be. accounted for, it is certain that the three ingredients are necessary to produce it. Saltpetre and sul- phur mixed together give no explosion ; sulphur and charcoal give no explosion; and though saltpetre and charcoal, when in. timately mixed, do yive an explosion, yet it is, probably, of far less force than what is produced from a mixture of the three ingredients. I have said probably, because this point does not seem to be quite settled at present, as may appear from the following opinions, of two eminent chemists, each of whom ap- peals to experience. — •' Un melange de six onces de nitre et d'unt once charbon produit une poudre qui a moitic mains de force que toutes cellos dans lesquelles on fait entrer du soufre : cette sub- stance est done absolument essentielle a la composition d<» la poudre. Dans le temps que je travailloi* sur cette matiere, quelques particuliers proposerent de faire de la poudre sans soufre: ils promettoient qu'elle seroit plus forte. La poudre dans laqiu-lla on fait entrer une petite quantite d<« soufre, augmente de force * EvHyn'i Silva, by Dr. Hunter, p. 223. f Id. p. 940. J Chvm- par M. Rcaurat, vol. I. p. 45 j. 176 COMPOSITION AND ANALYSIS OP GUNPOWDER. dii doubU §.'' — *' The principal ingredients of gunpowder, and those to which it owes its force, are nitre and charcoal; for these two ingredients well mixed together, constitute gunpow. der at least equal, if not superior in strength to common gun- powder, (as I found by experience,) and may be seen in the Memoire of Count Saluce, inserted in the Melanges de Philosophic et de Mathematiques, de 1'Academie Royale de Turin. The sul. phur seems to serve only for the purpose of setting fire to the mass with a less degree of heat*." If I may trust some crude experi- ments which I have made with a common powder trier, I must ac- cede to the opinion of M. Beaume, as I repeatedly found that equal bulks of common powder, and of the same sort of powder, freed from its sulphur by a gentle evaporation, differed very much both in the loudness and force of the explosion ; the powder which had lost its sulphur being inferior to the other in both particulars. It is not without reason, that equal bulks are here specified, for any definitive measure of common powder weighs more than the same measure of powder which has lost its sulphur; hence the re. suit of experiments made with equal weights of these powders, will be different from that which is derived from the explosion of equal bulks : may not this observation tend to reconcile the opinions be- fore mentioned ? But whether sulphur be an absolutely necessary ingredient in the composition of gunpowder or not, it is certain that an accurate mixture of the ingredients is essentially requisite. In order to accomplish this accurate mixture, the ingredients are previously reduced into coarse powders, and afterwards ground and pounded together, till the powder becomes exceeding fine ; and when that is done the gunpowder is made. But as gunpowder, in the state of an impalpable dust, would be inconvenient in its use, it has been customary to reduce it into grains, by forcing it, when moistened with water, through sieves of various sizes. The necessity of a complete mixture of the materials, in order to have good gunpowder, is sensibly felt, in the use of such as has been dried after having been accidentally wetted. There may be the same weight of the powder after it has been dried, that there was before it was wetted ; but its strength is greatly diminished on account of the mixture of the ingredients being less perfect. This diminution of strength proceeds from the water having dissolved a » Chym. par M. Bf:imu£, vol. 1. p. 461. f Philos. Trans. 1779, p. S97, where the reader will find several ingenious xperiinents relative to the nature of gunpowder, by Dr. Ingenbousx, COMPOSITION AND ANALYSIS OF GUNPOWDER. 177 portion of the saltpetre (the other two ingredients not being soluble in water ;) for upon drying the powder, the (Mssolved saltpetre will be crystallized in particles much larger than those were, which en- tered into the composition of the gunpowder, and thus the mixture will be less intimate and uniform, than it was before the wetting. This wetting of gunpowder is often occasioned by th»> mere mois- ture of the atmosphere. Great complaints were made concerning the badness of the gunpowder used by the English in their engage, ment with the French fleet off Grenada, in July \J7\i ; the French having done much damage to the masts and rigging of the English, when the English shot would not reach them. When this matter was inquired into by the House of Commons, it appeared that the powder had been injured by the moisture of the atmosphere ; it had concreted into large lumps, in the middle of which the saltpetre was visible to the naked eye. If the wetting has been considerable, the powder is rendered wholly unfit for use ; but if no foreign sub. stance has been mixed with it except fresh water, it may be made into good gunpowder again, by being properly pounded and gra- nulated. If the wetting has been occasioned by salt water, and that to any considerable degree, the sea salt, upon drying the pow- der, will remain mixed with it, and may so far vitiate its quality, that it can never be used again in the form of gunpowder. How- ever, as by solution in water and subsequent crystallization, the most valuable part of the gunpowder, namely, the saltpetre, may be extracted, and in its original purity, even from powder that has been wetted by sea water, or otherwise spoiled, the saving a da- maged powder is a matter of national economy, and deservedly at. tended to in the elaboratory at Woolwich. The proportions in which the ingredients of gunpowder are com- • bined together, are not the same in different nations, nor in dif- ferent works of the same nation, even for powder destined to the same use. It is difficult to obtain from the makers of gunpowder, any information upon this subject; their backwardness in this par- ticular arises, not so much from any of them fancying themselves possessed of the best possible proportion, as from an affectation of mystery common to most manufacturers, and an apprehension of discovering to the world that they do not use so much saltpetre as they ought to do, or as their competitors in trade really do use. Saltpetre is not only a much dearer commodity than either sulphur or charcoal, but it enters also in a much greater proportion into VOL. VI. N 178 COMPOSITION AND ANALYSIS OF GUNPOWDER. the composition of gunpowder, tlian both these materials taken together; hence, there is a great temptation to lessen tin- quantity of the saltpetre, and to augment that of the other inurtdi and the fraud is not easily detected, since gunpo\v(!-r, whirh will explode readily and loudly, may be made with very different quantities of saltpetre. Baptista Porla died in the year 1515 ; he gives three different portions for making of gunpowder, according as it was required to be of different strength*. I have reduced his proportions, so that the reader may see the quantities of the several ingredients, contained iti 100 pounds weight of each sort of powdt-r. Weak. Strong. Strongest. Saltpetre 66^-lb. 75 SO Sulphur 164 12^ 10 Charcoal 16y 121 10 10Q 100 100 It is somewhat remarkable, that in all these proportions, the sulphur and charcoal are used in equal quantities. Cardan died about sixty years after Baptista Porta, and in that interval, the proportions of the ingredients of gunpowder seem to have under- gone a great change. Cardan's proportions for great, middle, sized, and small guns, are expressed in the following table*. Gr. Guns. Mid. sized. Small. Saltpetre 50 Ib. 664 83| Sulphur 16*. 13} 87 Charcoal 33^ 20 81 T - i » - 100 100 100 For great and middle. sized guns, we see, a much greater pro- portion of charcoal than of sulphur was used in Cardan's time ; at present, I believe, it is in most places the reverse, or at least the charcoal no where exceeds the sulphur. I have put down the proportions used at present in England, France, Sweden, Poland, and Italy, for the best kind of gunpowder. • Maj. Nut. L. XII. c. 3. <• Card. Opcr. Vol. III. p. 379. COMPOSITION AND ANALYSIS OP GUNPOWDER. 179 I -upland. France. Sweden. Poland. Italv. Saltpetre 75 75 75 , 80 Sulphur lo 9i 16 12 124 Charcoal 10 151 9 8 12* *100 loo}) looj: loot 100{t Several experiments have been lately made in France, in order to determine the exact proportions of the several ingredients which would produce the strongest possible power; these proportions when reduced, as all the rest hare been, to the quantity compos. ing one hundred pounds of gunpowder, are Saltpetre , . . . 80 Ib. Charcoal . . . . 15 Sulphur . • . • 5 100 From hence it would appear, that in a certain weight of saltpetre, the powder would produce the greatest effect, when the weight of the charcoal was to that of tke sulphur, as 3 to 1. On the other hand, experiments are produced from which it is to be concluded, that in a certain weight of saltpetre the best powder is made, when the sulphur is to the charcoal, in the proportion of 2 to 1 . From these different accounts, it seems as if the problem of determining the very best possible proportion was not yet solved. In drying gun. powder, after it is reduced into grains, there are two things to be avoided, too much and too little heat. If the heat is too great, a portion of the sulphur will be driven off, and thus the proportion of the ingredients being changed, the goodness of the powder, so far as it depends on that proportion, will be injured. In order to see what quantity of sulphur might be separated from gun. powder, by a degree of heat not sufficient to explode it, I took 24 grains of the powder marked F F in the shops, and placing • Tlic»f an* said to be the proportions of government powder. — Pemb. Chem. p. SOT. fl Chem Dirt. & Baumfe's Chem. Vol. I. 466. f Mom. de. Chem. Vol. II. p. 425, where it ia said, that two specimens of powder from Holland gave only 711b. of saltpetre from 100 of powder, Coinm. Scien. Bonon. Vol. IV. p. 133. 180 COMPOSITION AND ANALYSIS OF GUNPOWDER. it on a piece of polished copper, I heated the copper by holding it over the flame of a candle ; the gun. powder soon sent forth a sul. phureous vapour ; and when it had been dried so long that no more fume or smell could be distinguished, the remainder weighed nine, teen grains, the loss amounting to five grains. The remainder did wot explode by a spark like gunpowder, but like a mixture of salt, pt-tre and charcoal, and it really was nothing else, all the sulphur having been dissipated. Gunpowder was formerly dried by being exposed to the heat of the sun, and this method is still in use in France, fand in some other countries ; afterwards a way was in- Tented of exposing it to a heat equal to that of boiling water; at present it is most generally in England dried in stoves, heated by great iron pots ; with any tolerable caution no danger of explosion need be apprehended from this method. All the watery parts of the gunpowder may be evaporated by a degree of heat greatly less than that in which gunpowder explodes ; that degree haying been ascertained by some late experiments, to be about the 600th degree on Fahrenheit's scale, in which the heat of boiling water is fixed at 2 1 2. There is more danger of evaporating a portion of the sulphur in this way of drying gunpowder, than when it is dried by exposure to the sun. The necessity of freeing gunpowder from all its moisture, is obvious from the following experiment, which was made some years ago before the Royal Society. A quantity of gunpowder was taken out of a barrel, and dried with a heat equal to that in which water boils ; a piece of ordnance was charged with a certain weight of this dried powder, and the distance to which it threw a ball was marked. The same piece was charged with an equal weight of the same kind of powder, taken out of the same barrel, but not dried, and it threw an equal ball only to one half the distance. This effect of moisture is so sensible, that some officers have affirmed, that they have seen barrels of gunpowder which was good in the morning, but which became (by attracting, probably, the humidity of the air) good for nothing in the evening*. In order to keep the powder dry, by preventing the access of the air, it has been pro. posed to line the barrels with tin foil, or with thin sheets of lead, after the manner in which tea boxes are lined f. Would it not be *— qu'il avoit vu, dans les guerrcs d'ltalic, quelquc barrels dc poudre qui £toit bonne IP matin, etqui nc valoit rien le soir. Hist. Natt de 1'Espagne, p.82. Hint Nat.de I'Espagne. COMPOSITION AND ANALYSIS OF GUNPOWDER. 181 possible to preserve powder free from moisture, and from the loss of a part of its sulphur in hot climates, by keeping it in glazed earthen bottles, or in bottles made of copper or tin, well corked ? This disposition to attract the humidity of the air, is different in different sorts of powder, it is the least in that which is made from the purest saltpetre ; ptire saltpetre, which has been dried as gunpowder is dried, does not become heavier by exposure to the atmosphere ; at least, its increase of weight is very small, not amount, jng, as far as my experiments have informed me, to above one 72d part of its weight ; I rather think that it does not acquire any in. crease of weight. But saltpetre mixed with sea salt, attracts the humidity very sensibly ; and hence, though there should be the same weight of saline matter in a certain weight of gunpowder, yet the goodness of the powder may be very variable, not only from the foreign saline matter, be it sea salt, or any other salt, injuring the quality of the powder as being an improper ingredient, but from its rendering the powder more liable to become humid. Saltpetre being the ingredient, in which there is the greatest room for fraud, in the composition of gunpowder, and on the quantity of which its strength chiefly depends, the reader will excuse the mi. nuteness of the following process, to ascertain the quantity of salt, petre contained in any specimen of gunpowder. Take any quantity of gunpowder, pound it in a glass mortar till all the grains are broken, lay it before a gentle fire till it be quite dry ; in that state weigh accurately any quantity of it, suppose four ounces; boil these four ounces in about a quart of water; the boiling need neither be violent nor long continued, for the water will readily dissolve all the saltpetre, or other saline matter, and not a particle of either the sulphur or the charcoal of the powder. In order to separate the water containing the saltpetre, from the sulphur and charcoal, pour the whole into a filter made of brown paper; the water containing the saltpetre will run through the paper, and must be carefully preserved ; the charcoal and sulphur •will remain upon the paper. But as some particles of saltpetre will stick both to the filtering paper, and to the mass of sulphur and charcoal, these are to be repeatedly washed, by pouring hot water upen them, till the water in running through the filter is quite in. sipid; then we may be certain, that we have all the saltpetre ori- ginally contained in the powder, now dissolved in the water, and y 3 COMPOSITION AND ANALYSIS OF GVNPOWDFR. all the sulphur and charcoal remaining a fixed mass upon the. filter. Tin si- respective qiian'ities may be ascertained \\itlmut much diili. cnltv. Tin- water containing the dissolved ^altpelrc, must be • porated by a gentle IK at ; the -altpefre cannot be evaporated by the same decree of heat which evaporates the water; all the saltpetre thc-n contained in the gunpowder, will remain after the water is dispersed, and being carefully collected and weighed, it will shew the quantity of saline matter contained in the powder. Dry the mass of sulphur and charcoal, by laying the filtering paper con. tain'mg it before the fire; it should be made as dry as the powder was before it was dissolved in the water : in that state weigh the saltpetre and charcoal ; and, when the experiment has been accu- rately made, the weight of the saltpetre, added to that of the mix- ture of sulphur and charcoal, will just amount to four ounces, the weight of the powder. The quantity of saline matter contained in any specimen of gunpowder, being thus ascertained, its quality may be, known b> dissolving it in water, and crystallizing it; if any part of it crystallizes in little cubes, it is a sign that it contains sea-salt; or if any part of it, after being duly evaporated, will not crystallize, it is a sign that it contains another sort of impurity, cal rd by saltpetre makers, the mother of nitre, which powerfully attracts the humidity of the air. Tin. 'gunpowder marked FF, was analysed in the following man- ner. Twenty-four grains, by evaporating the sulphur, were re. duced to nineteen ; these nineteen grains gave, by solution in water and subsequent filtration and crystallization, sixteen graitu of saltpetre; the charcoal, when properly dried, weighed three grains. According to these proportions, 100 pounds of this kind of gunpowder consisted of Saltpetre . . . 66^ Sulphur . . . 20| Charcoal . . . 12} lOOlbs. I tried this gunpowder in two or three other ways by taking larger quantities of it, but the quantity of saltpetre was always 66 Ib. together with some f/actional part of a po-ind, from lOOlb. of gunpowder. The powders marked with a single and a double p, differ in the size of the grain, but they do not seem to differ, as COMPOSITION AND ANALYSIS OF GUNPOWDER. 183 far as I have tried them, in the quantity of the saltpetre they con. lain. From some sorts of powder, I hare got after the rate of 7615. of saltpetre, from lOOlb. of the gunpowder. The method of analysing gunpowder, by evaporating the sulphur, is not wholly to be relied upon ; I have often observed, that when mixtures of sulphur and charcoal have been exposed to evapora- tion, on a plate of heated copper, the remainder has weighed loss than the charcoal which entered the composition, part of it having been carried off by the violent evaporation of the sulphur: and hence the proportion of sulphur in the above analysis is probably too great. I am aware that this observation is wholly opposite to the conclusion of M. Beaume, who contends, that one twenty. fourth part of the weight of the sulphur employed in any mixture of sulphur and charcoal, adheres so strongly to the charcoal, that it cannot be se. parated from it without burning the charcoal. — I can only say, that he separated the sulphur by burning it, and 1 separated mine by subliming it without suffering it to take fire, and this difference in the manner of making the experiment, may perhaps be sufficient to account for the different results. — But it is unnecessary to pursue this subject further ; there are several things to be attended to in. forming a complete analysis of gunpowder, which any person tole- rably well versed in chemistry, would certainly take notice of, if the analysis of any particular powder was required to be made, and which cannot, in this general view, be minutely described : and, indeed, it is the less necessary to enter into a detail on this subject, as the strength of the powder is not so much affected by small variations in the quantities of the sulphur and charcoal, which enter into its composition ; and the method of ascertaining the quantity and quality of the saltpetre, in any particular gunpowder, has been sufficiently explained. la order to judge with more certainty concerning the effect of sea.salt, when mixed with saltpetre in attracting the humidity of the air, I made the following experiment. Five parts of pure salt- petre in powder, were exposed for a month to a moist atmosphere, but I did not observe that the saltpetre hod gained the least increase of weight ; for the same length of time, and in the same place, I exposed four parts of saltpetre mixed with one of common salt, and this mixture had attracted so much moisture, that it was in a state of fluidity. [Bishop JValson. N4 184 FULMINATING POWDERS. Besides saltpetre or the nitric acid, which is the active ingredient in saltpetre, there are various other acidsr as the oxymuriatic, (chlorine of Davy), the hyper oxymuriatic, the arsenic, tun.stic, molybdic, and columbic, that are powerful supporters of combus- tion. Of these the most easy of access is the oxymuriatic ; and this has in consequence been tried either instead of, or in conjunc- tion with, the nitric acid, to ascertain whether it be possessed of more power. The best experiments upon the subject are those of Edward Howard, Esq. as communicated to the Royal Society. The effect, according to these, is very singular, in the employment of the oxymuriat of potash, the only form in which the oxymuriatic acid has hitherto been made use of. It acts with considerably more energy so far as its range extf nds ; but this range is far .short of that produced by saltpetre, or nitrat of potash. It produces also a much more violent explosion ; and an explosion which, in one instance, burst the vessel, and nearly destroyed the eye.sight of the bold and ingenious experimenter. [Editor. CHAP. XIV. FULMINATING POWDERS. 1 HERE are various combinations under this name that possess a near resemblance to gunpowder in their constituent parts, easily inflame, and explode with great violence, but require a certain degree of heat to produce this effect. We shall notice the com. mon and the metallic fulminating powders. SECTION I. Common Fulminating Powder. Tins is prepared as follows : take three parts of nitre, two of purified pearl-ash, and one of flowers of sulphur, mix the whole very accurately in an earthen mortar, and placo it on a tile or plate before the fire, till it is perfectly dry : then transfer it while hot into a ground stopper bottle, and it may be kept without injury for any length of time. In order to experience its effects, pour from ten to forty grains into an iron ladle, and place it over a slow fire : FULMINATING GOLD AND SILVER. 185 in a short time the powder becomes brown and acquires a pasty consistence ; a blue lambent flame then appears on the surface, and in an instant after the whole explodes with a stunning noise and a slight momentary flash. If the mass be removed from the fire as soon as it is fused, and kept in a dry well. closed vial, it may at any time be exploded by a spark, in which case it burns like gunpowder, but more rapidly and with greater detonation ; but this effect cannot be produci-d on the unmelted powder, how accu- rately soever the ingredients of it are mixed together. When fulminating powder is in fusion, but not heated to the degree ne- cessary to produce the blue flame, a particle of ignited charcoal thrown upon it will occasion immediately a remarkably loud ex. plosion. It appears that the ingredients of this powder do not acquire their fulminating property till combined by fusion ; in other words, till the pot. ash of sulphur form sulphuret of pot-ash : whence ful- minating powder may also be made by mixing sulphuret of pot- ash with nitre, instead of by adding the sulphur and alkali sepa- rate. In all these the cause of the detonation, or fulminatidn, is not accurately understood. In simple fulminating powder, there is a very large portion of elastic gass evolved ; in fulminating gold or silver, a much smaller ; yet the explosion in the latter case is infinitely greater than that in the former. Fulminating Gold. Dissolve pure gold in nitro-muriatic acid to saturation, and di- lute the solution with three times its bulk of distilled water, and add to it gradually some pure ammonia ; a yellow precipitate will be obtained, which must be repeatedly washed with distilled water, and dried on a chalk stone, or in a filter. When perfectly dry, it is called fulminating gold, and detonates by heat, as may be shewn by heating a few grains of it on the point of a knife over the candle. * Fulminating Silver. Dissolve fine silver in pale nitric acid, and precipitate the solu- tion by lime. water ; decant the fluid, mix the precipitate with liquid ammonia, and stir it till it assumes a black colour j then de. cant the fluid, and leave it in the open air to dry. This product is fulminating silver, which when once obtained cannot be touched ISfi FULMINATING MERCURY. without producing a violent explosion. It is the most dangeroitt preparation known, for the contact of fire is not necessary to cause it to delonatp. It explodes by the mere touch. Its preparation is so hazardous, that it ought not to be attempted without a mask, with strong glass eyes, upon the face. No more than a single grain ought at any time to be tried as an experiment. This was invented by M. Bcrlhollct. M. Chenevix luis invented a fulminating silver, not so dangerous as that just mentioned. It explodes only by a slight friction in contact with combustible bodies. It is thus prepared: diffuse a quantity of alumina through water, and let a current of oxygenated muriatic acid gass pass through it for some time. Then digest some phosphate of silver on the solution of the oxygenated muriate of alumina, and evaporate it slowly. The product obtained will be a hyper. oxygenated muriate of silver, a single grain of which, in contact with two or three of sulphur, will explode vio. leutly with the slightest friction. Fulminating Mercury. The mercurial preparations which fulminate, when mixed with sulphur, and gradually exposed to a gentle heat, are well known to chemists : they were discovered, and have been fully described, by Mr. Bay en. MM. Brugnatelli and Van Mons have likewise produced ful- ininations by concussion, as well by nitrat of mercury and phos- phorus, as with phosphorus and most other nitrats. Cinnabar also is amongst the substances which, according to MM. Four- croy and Vauquelin, detonate by concussion with oxymuriat of potash. M. Ameilon had, according to M. Bertholler, observed, that /the precipitate obtained from nitrat of mercury, by oxalic acid, fuses with a hissing noise. But mercury, and most, if not all its oxyds, may, by treatment Vith nitric acid and alcohol, be converted into a whitish crystal- lized powder, possessing all the inflammable properties of gun- powder, as well as many peculiar to itself. " I was led to this discovery," says Mr. Howard, the inventor, « by a late assertion, that hydrogen is the basis of the muriatic acid : it induced me to attempt to combine different substances with hy- drogen and oxygen. With this view I mixed such substances with FULMINATING MERCURY. 187 alcohol and nitric acid as might (by predisposing affinity) favour as well as attract an acid combination of the hydrogen of the one, and the oxygen of the other. The pure red oxyd of mercury appeared not unfit for this purpose j it was therefore intermixed with alcohol, and upon both nitric acid was alfused. The acid did not act upon the alcohol so immediately as when these fluids are alone mixed to- gether, but first gradually dissolved the oxyde : however, after some minutes had elapsed, a smell of ether was perceptible, and a white dense smoke, much resembling that from the liquor fumans of Libavius, was emitted with ebullition. The mixture then throve down a dark-coloured precipitate, which by degrees became nearly white. This precipitate -I separated by filtration ; and observing it to be crystallised in smaller acicular crystals, of a saline taste, and also finding a part of the mercury volatilized in the white fumes, I must acknowledge, I was not altogether \\ithouthopes that muriatic acid had been formed, and united to the mercurial oxide ; 1 there, fore, for obvious reasons, poured sulphuric acid upon the dried crystalline mass, when a violent effervescence ensued, and, to my great astonishment, an explosion took place. The singularity of this explosion induced me to repeat the process several times ; and finding that I always obtained the same kind of powder, I pre- pared a quantity of it, and was led to make the series of expert, ments which I shall have the honour to relate in this paper. " I first attempted to make the mercurial powder fulminate by concussion ; and for that purpose laid about a grain of it upon a cold anvil, and struck it with a hammer, likewise cold. It deto. nated slightly, not being, as I suppose, struck with a flat blow ; for upon using three or four grains, a very stunning disagreeable noise was produced, and the faces both of the hammer and the anvil were much indented. " Half a grain, or a grain, if quite dry, is as much as ought to be used on such an occasion. u The shock of an electrical battery, sent through five or six grains of the powder, produces a very similar effect. It seems, indeed, that a strong electrical shock generally acts on fulminating substances like the blow of a hammer. Messrs. Fourcroy and Vauquelin found this to be the case, with all their mixtures of oxy. muriate of potass. " To ascertain at what temperature the mercurial powder ex. plodes, two or three grains of it were floated on oil, in a capsule of 183 CULMINATING MERCURY. leaf tin ; the bulb of a Fahrenheit's thermometer was made just to touch the surface of the oil, which was then gradually heated till the powder exploded, as the mercury reached the 368th degr. " Desirous of comparing the strength of the mercurial compound with that of gunpowder, I made the following e.\p« liment in the presence of my friend Mr. Abernethy. tf Finding that the powder could not be fired with flint and steel, without a disagreeable noise, a common gunpowder proof, capable of containing eleven grains of fine gunpowder, was filled with it, and fired in the usual way : the report was sharp, but not loud. The person who held the instrument in his hand felt no re. coil j but the explosion laid open the upper part of the barrel, nearly from the touch-hole to the muzzle, and struck off the hand of the register, the surface of which was evenly indented, to the depth of 0.1 of an inch, as if it had received the impression of a punch. " The instrument used in this experiment being familiarly known, it is therefore scarcely necessary to describe if. : sullkt. it to say, that it was brass, mounted with a spring registrr, the hand of whL.h closed up the muzzle, to receiv and IT' ' nee of the explosion. The barrel w.s and nearly half an inch thick, except where .. impaired half its thickness. " A gun belonging to Mr. Keir, an ingenious artist of i. am Town, was next charged with seventeen grains of the mercurial powder, and a leaden bullet. A block of wood was placed at about eight yards from the muzzle to receive the ball, and the gun was fired by a fuse. No recoil seemed to have taken place, as the barrel was not moved from its position, although it was in no * confined. The report was feeble; the bullet, Mr. Keir conceived, from the impression made upon the wood, had been projected with about half the force it would have been by an ordinary charge, or sixty-eight grains, of the best gunpowder. We therefore re- charged the gun with thirty. four grains of the mercurial powder; and as the great strength of the piece removed any apprehension of danger, Mr. Keir fired it from his shoulder, aiming at the same block of wood. The report was like the first, sharp, but not louder than might have been expected from a charge of gunpowder. Fortunately Mr. Keir was not hurt; but the gun was burst in an extraordinary manner. The breech was what is called a patent FULMINATING MERCURT. 189 one, of the best forged iron, consisting of a chamber 0.4 of an inch thick all round, and 0.4 of an inch in calibre ; it was torn open and flawed in many directions, and the gold touch. hole driven out. The barrel into which the breech was screwed was 0.5 of an inch thick ; it was split by a single crack three inches long, but this did not appear to me to be the immediate effect of the explosion. I think the screw of the breech, being suddenly enlarged, acted as a wedge upon the barrel. The ball missed the block of wood, and struck against a wall, which had already been the receptablc of so many bullets, that we could not satisfy ourselves about the impres. sion made by this last. ** As it was pretty plain that no gun could confine a quantity of the mercurial powder sufficient to project a bullet with a greater force than an ordinary charge of gunpowder, I determined to try its comparative strength in another way. I procured two blocks of wood, very nearly of the same size and strength, and bored them with the same instrument to the same depth. The one was charged with half an ounce of the best Dartford gunpowder, and the other with half an ounce of the mercurial powder ; both were alike buried in sand, and fired by a train communicating with the powders by a small touch-hole. The block containing the gun. powder was simply split into three pieces : that charged with the mercurial powder was burst in every direction, and the parts im. mediately contiguous to the powder were absolutely pounded, yet the whole hung together, whereas the block split by the gun. powder had its parts fairly separated. The sand surrounding the gunpowder was undoubtedly the most disturbed ; in short, the mercurial powder appeared to have acted with the greatest energy, but only within certain limits. " The effects of the mercurial powder, in the last experiments, made me believe that it might be confined, during its explosion, in the centre of a hollow glass globe. Having therefore provided such a vessel, seven inches in diameter, and nearly half an inch thick, mounted with brass caps, and a stopcock, I placed ten grains of mer- curial powder on thin paper, laid on iron wire 149th of an inch thick across the paper, through the midst of the powder, and, closing the paper, tied it fast at both extremities with silk to the wire. As the inclosed powder was now attached to the middle of the wire, each end of which was connected with the brass caps, the packet of powder, became by this disposition, fixed in the centre of the globe. Such a charge of an electrical battery was then sent ajorig 190 F1LMINATING MERCURY. the wire, as a preliminary experiment (with Mr. Cuthberf electrometer) had .shewn me would, by making the wire red hot, inllamc the powder. The glass globe withstood the explosion, and of course retained whatever gasses were generated ; its interior was thinly coated with quicksilver, in a very divided state. A bent gla>s tube was now screwed to the stop. cock of the brass cap, •which being introduced under a glass jar standing in the mercurial bath, the stop-cock was opened. Three cubical inches of air rushed out, and a fourth was set at liberty when the apparatus was removed to the water tub. The explosion being repeated, and the air all received over water, the quantity did not vary. To avoid an error from change of temperature, the glass globe was, bofh be- fore and after the explosion, immersed in water of the same tem- perature. It appears, therefore, that the ten grains of powder produced four cubical inches only of air. *' To continue the comparison between the mercurial powder and gunpowder, ten grains of the best Dartford gunpowder were in a similar manner set (ire to in the glass globe : it remained en. tire. The whole of the powder did not explode, for some com. plete grains were to be observed adhering to the interior surface of the glass. Little need be said of the nature of the gasses generated during the combustion of the gunpowder : they must have been carbonic acid gass, sulphureous acid gass, nitrogen gass, and (ac- cording to Lavoisier) perhaps hydrogen gass. As to the quantity of these, it is obvious that it could not be ascertained : because the two first were, at least in part, speedily absorbed by the alkali of the nitre, left pure after the decomposition of its nitric acid." The following description will give the experimental philosopher a clear idea of the instrument used in this business. The ball or globe of glass is nearly half an inch thick, and seven inches in diameter. It has two necks, on which is cemented two brass caps, «each being perforated with a female screw, to receive the male ones; through the former a small hole is drilled; the latter is furnished with a perforated stud or shank. By means of a leather collar the neck can be air-tightly closed. When a por- tion of the powder is to be exploded, it must be placed on a piece of paper, and a small wire laid across the paper, through the midst of the powder ; the paper being then closed, is to be tied at each end to the wire with a silken thread. One end of this wire is to be fastened to the end of the shank, and the screw inserted to half its length into the brass cap ; the other end of the wire, by means of a FULMINATING ME11CURT. HJl needle, is to be drawn through (he hole. The screw being no»r fixed in its place, and the wire drawn tight, is to be secured by pushing the irregular wooden plug into the aperture of the screw, taking care to leave a passage for the air. The stop. cock is now to be screwed on. The glass tube is bent, that it may more conve- niently be introduced under the receiver of a pneumatic apparatus. "Fromsomeoftheexperirnents (continues Mr. Howard) in which the gunpowder proof and the gun were burst, it might be inferred, that the astonishing force of the mercurial powder is to be attributed to the rapidity of its combustion ; and a train of several inches in length being consumed in a single flash, it is evident that its combus- tion must be rapid. But from other experiments it is plain that this force is restrained to a narrow limit, both because the block of wood charged with the mercurial powder was more shattered than that charged with the gunpowder, whilst the sand surrounding it was least disturbed, and likewise because the glass globe withstood the explo- sion often grains of the powder fixed in its centre; a charge I had twice found sufficient to destroy old pistol barrels, which were not injured by being fired when full of the best gunpowder. It also appears from the last experiment, that ten grains of the powder produced by ignition four cubical inches only of air; and it is not to be supposed that the generation, however rapid, of four cubical inches of air, will alone account for the described force ; neither can it be accounted for by the formation of a little water, which, as will hereafter be shewn, happens at the same moment; the quantity formed from ten grains must be so trifling, that I cannot ascribe much force to the expansion of its vapour. The sudden vaporation of a part of the mercury seems to me a principal cause of this immense yet limited force; because its limitation may then be explained, as it is well known that mercury easily parts with ca- loric, and requires a temperature of 600° of Fahrenheit, to be maintained in the vaporous state. That the mercury. is really con. terted into vapour, by ignition of the powder, may be inferred from the thin coat of divided quicksilver, which, after the explo- sion in the glass globe, covered its interior surface; and likewise from the quicksilver with which a tallow candle, or a piece of gold, may be evenly coated, by being held at a small distance from the inflamed powder. These facts certainly render it more than pro- bable, although they do not demonstrate that the mercury is Tola, tilued; because it is not unlikely that many mercurial particles 19C LMINAT1NG MERCURY. arc mechanically impelled against the surface of the glass, the gold, and tlie tallow. " As to the force of the dilated mercury, M. Beaume relates a remarkable instance of it, as follows : " Un alchymiste se presenta a Mr. GeoflVoy, et 1'assura qu'il avoit trouve le nioycn de fixer le mercure par une operation fort simple. II fit construire six boitcs rondes en fer fort epais, quien- troient les unes dans les autres ; la derniere etoit assujettie par deux oerrles de fer qui se croisoient en angles droits. On avoit mis quelques livres de mercure dans la capacite de la premiere ; on mit cet appareil dans un fourneau assez rempli de charbon pour faire rougir a blanc les boites de fer; mais, lorsqm- la chaleur eut penetre suflisamment, le mercure, les boites creverent, avec une telle explosion qu'il se fit un bruit epouvantable ; des morceaux de boites furcnt lances avec tant de rapidite qu'il y en eut qui passe, rent au travers de deux planchers ; d'autres firent sur la muraille des effets semblables a ceux des eclats de bombes*." *' Had the alchemist proposed to fix water by the same appa. ratus, the nest of boxes must, I suppose, have likewise been rup- tured ; yet it does not follow that the explosion would have been so tremendous ; indeed, it is probable that it would not, for if (as Mr. Kirwan remarked to me) substances which have the greatest specific gravity have likewise the greatest attraction of cohesion, the supposition that the vapour of water, would agree with a posi. tion of Sir Isaac Newton, that those particles recede from one another with the greatest force, and are most difficultly brought to- gether, which upon contact cohere most strongly. " Before I attempt to investigate the constituent principles of this powder, it will be proper to describe the process and manipu- lations which, from frequent trials, seem to be best calculated to produce it. One hundred grains, or a greater proportional quan. tity of quicksilver, (not exceeding 500 grains), are to be dissolved, with heat, in a measured ounce and a half of nitric acid. This solu- tion being poured cold upon two measured ounces of alcohol, previ- ously introduced into any convenient glass vessel, a moderate heat is to be applied until an effervescence is excited. A white fume then begins to undulate on the surface of the liquor ; and the powder will be gradually precipitated, upon the cessation of action and re. * Chymie E*p£rimentale et Raisonn6, torn. ii. p. 59"?. FULMINATING MERCURT. action. The precipitate is to be immediately collected on a filter, well washed with distilled water, and carefully f'.-ied in a heat not much exceeding that of a water-bath. The immediate edulcoration of the powder is material, because it is liable to the reaction of ni. trie acid ; and, whilst any of that acid adheres to it, it is >ery sub- ject to the influence of light. Let it also be cautiously remembered, that the mercurial solution is to be poured upon the alcohol. " I have recomnv nded quicksilver to be used in preference to an oxyd, because it seems to answer equally, and is less expensive; otherwise, not only the pure red oxyd, but the red nitrous oxide, and turpcth, may be substituted ; neither does it seem essential to attend to the precise specific gravity of the acid, or the alcohol. The rectified spirit of wine, and the nitrous acid of commerce, never failed with me, to produce a fulminating mercury. It is in. deed true, that the powder prepared without attention is produced in different quantities, varieties in colour, and probably in strength. From analogy, I am disposed to think the whitest is the strongest ; for it is well known that the black precipitates of mercury ap- proach nearest to the metallic state. The variation in quantity is remarkable: the smallest quantity I ever obtained from 100 grains of quicksilver beinjj 120 grains, and the largest 132 grains. Much depends on very minute circumstances. The greatest product seems to be obtained when a vessel is used which condenses and causes most ether to return into the mother liquor ; besides which, care is to be had in applying the requisite heat, that a speedy and not a violent action be ellected. One hundred grains of an oxide are not so productive as 100 grains of quicksilver. " As to the colour, it seems to incline to black when the action of the acid of the alcohol is most violent, and vice versa. *' I need not observe, that the gasses which were generated dur- ing the combustion of the powder in the glass globe, were neces- sarily mixed with atmospheric air ; the facility with which the electric fluid passes through a vacuum, made such a mixture un- avoidable. " The cubical inch of gass received over water was not readily absorbed by it; and, as it soon extinguished a taper without be- coming red, or being itself inflamed, barytes water was let up to the three cubical inches received over mercury, when a carbonate of barytes was immediately precipitated. " The residue of several explosions, after the carbonic acid bad VOL. vi. ° 194 FULMINATING MERCUR7. been separated, was found, by the test of nitrous gass, to contain nitrogen or azotic g;is ; which docs not proceed from any d<>compa- sition of atmospheric air, because the powder may be made to ex- plod*- under the exhausted receiver of an air-pump. It is there- fore manifest that the gasses generated during the combustion of the fulminating mercury, consist of carbonic acid and nitrogen gasses. u Th" principal re-agent* which decompose the mercurial pow- der are the nitric, the sulphuric, and the muriatic acids. The nitric changes the whole into nitrous gass, carbonic acid gass, acetout acid, and nitrate of mercury. I resolved it into these different principles, by distilling it pneumatically with nitric acid : this acid upon the application of heat soon dissolved the powder, and extricated a quantity of gass, which was found, by well-known tests, to be nitrous gass mixed with carbonic acid gass. The dis- tillation was carried on until gass no longer came over. The liquor of the retort was then mixed with the liquor collected in the receiver, and the whole saturated with potass ; which precipi- tated the mercury into a yellowish brown powder, nearly as k would have done from a solution of nitrate of mercury. This pre- cipitate was separated by a filter, and the filtrated liquor evapo- rated to a dry salt, which was washed with alcohol. A portion of the salt being refused by this menstruum, it was separated by fil- tration, and recognized, by all its properties, to be nitrate of potass. The alcohol liquor was likewise evaporated to a dry salt, which upon the effusion of a little concentrate sulphuric acid, emitted acetous acid, contaminated with a feeble smell of nitrous acid, owing to the solubility of a small portion of the nitre in the alcohol. " The sulphuric acid acts upon the powder in a remarkable man- ner, as has already been noticed. A very concentrate acid pro. duced an explosion nearly at the instant of contact, on account, I presume, of the sudden and copious disengagement of caloric from a portion of powder which is decomposed by the acid. An acid somewhat less concentrate likewise extricates a considerable quan. tity of caloric, with a good deal of gass; but as it effects a com- plete decomposition, it causes no explosion. An acid diluted with an equal quantity of water, by the aid of a little heat, separates the gass so much less rapidly, that it may with safety be collected in a pneumatic apparatus. But, whatever be the density of the acid FULMINATING MRKCURY. 1Q3 (provided no explosion be produced), there remains in the snl. phuric liquor, after tho separation of the gass, a white uninflam- mable and uncrystallized powder mixed with some minute globulei of quicksilver. " To estimate the quantity, and observe the naturo, of this unin- flammable substance, I treated 100 grains of the fulminating mer- cury with sulphuric acid a little diluted. The gass being sepa- rated, I decanted off the liquor as it became clear, and freed the insoluble powder from acid by edul< oration with distilled water ; after which I dried it, and found it weighed only eighty, four grains ; consequently had lost sixteen-grains of its original weight. Suspecting, from the operation of the nitric acid in the former experiment, that these eighty-four grains (with the excep- tion of the quicksilver globules) were oxalate of mercury, I di- gested them in nitrate of lime and found my suspicion just. The mercury of the oxalate united to the nitric acid, and the oxalic acid to the lime. A new insoluble compound was formed ; it weighed, when washed and dry, 48.5 grains. Carbonate of potass separated the lime, and formed oxalate of potass, capable of preci- pitating lime. water and muriate of lime ; although it had been de- purated from excess of alkali, and from carbonate acid, by a pre- vious addition of acetous acid. That the mercury of the oxalate in the eighty-four grains had united to the nitric acid of the ni- trate of lime was proved, by dropping muriatic acid into liquor from which the substance demonstrated to be oxalate of lime had separated; for a copious precipitation of calomel instantly en* sued. " The sulphuric liquor, decanted from the oxalate of mercury, was now added to that with which it was edulcorated, and the whole saturated with carbonate of potass. As effervescence ceased, a cloudiness and precipitation followed ; and the precipitate being collected, washed and dried, weighed 3.4 grains : it appeared to be a carbonate of mercury. Upon evaporating a portion of the sa- turated sulphuric liquor, I found nothing but sulphate of potass : nor had it any metallic taste. There then remains, without allow- ing for the weight of the carbonic united to the 3.4 grains, a deficit from the 100 grains of mercurial powder of 12.6 grains, which I ascribe to the gass separated by the action of the sulphuric acid. To ascertain the quantity, and examine the nature of the gass 10 FULMINATING MERCURY. separated, I introduced into a very small tubulated retort fifty grains of the mercurial powder, and poured upon it three drachms, by measure, of j-ulphuric acid, with the assistance of a gentle heat. I first received it over quicksilver; the surface of which, during the operation, partially covered itself with a little black powder. " The gass, by different trials, amounted to from twenty-eight to thirty-one cubical inches : it first appeared to be nothing but carbonic acid, as it precipitated barytes water, and extinguished a taper, without being itself inflamed, or becoming red. But upon letting up to it liquid caustic ammonia, there was a residue of from five to seven inches, of a peculiar inflammable gass, which burnt with a greenish. blue flame. When I made use of the water-tub, I obtained, from the same materials, from twenty-five to twenty, seven inches only of gass, although the average quantity of the peculiar inflammable gass was likewise from five to seven inches : therefore, the difference of the aggregate product, over the two fluids, must have arisen from the absorption, by the water, of a part of the carbonic acid in its nascent state. The variation of the quantity of the inflammable gass, when powder from the same parcel is used, seems to depend upon the acid being a little more or less dilute. u With respect to the nature of the peculiar inflammable gass, it is plain to me, from the reasons I shall immediately adduce, that it is no other than the gass (in a pure state) into which the nitrous etherized gass can be resolved, by treatment with dilute sulphuric acid. " The Dutch chemists have shewn, that the nitrous etherized gass can be resolved into nitrous gass, by exposure to concentrate sul- phuric acid ; and that, by using a dilute instead of a concentrate acid, a gass is obtained which enlarges the flame of a burning taper, so much like the gasseous oxide of azote, that they mistook it for that substance, until they discovered that it was permanent over water ; refused to detonate with hydrogen ; and that the fallacious appearance was owing to a mixture of nitrous gass with inflammable gass. " The inflammable gass, separated from the powder, answers to the description of the gass which at first deceived the Dutch chemists : 1st, in being permanent over water ; 2dly, refusing t* FULMINATING MERCURY. detonate with hydrogen ; and 3d!y, having the appearance of th« gusseous oxide of azote, when mixed uith nitrous gass. " The gass separable by the same acid, from nitrous etherized gass, and from the mercurial powder, have therefore the same properties. Every chemist would thence conclude, that the ni- trous etherized gass is a constituent part of the powder; and the inflammable and nitrous gass, instead of the inflammable and car. bonic acid gass, had been the mixed product extricated from it by dilute sulphuric acid. " It however appears to me, that nitrous gass was really pro- duced by the action of the dilute sulphuric acid; and that, when produced, it united to an excess of oxygen, present in the oxalate of mercury. " To explain how this change might happen, I must premise, that my experiments have shewn me, that oxalate of mercury can exist in two, if not in three states. 1st. By the discovery of Mr. Ameilon, the precipitate obtained by oxalic acid, from nitrate of mercury, fuses with a hissing noise. The precipitate is an oxalate of mercury, seeming!} with excess of oxygrn. Mercury dissolved in sulphuric acid, and precipitated by oxalic acid, and also the pure red oxide of mercury, digested with oxalic acid, give oxalates in the same state. 2dly. Acetate of mercury, precipitated by oxalic acid, although a true oxalate is formed, has no kind of inflammability. 1 consider it as an oialate, with less oxygen than those above mentioned. 3dly. A solution of nitrate of mercury, boiled with dulcified spirit of nitre, gives an oxalate more inflam- mable than any other ; perhaps it contains most oxygen. " The oxalate of mercury, remaining from the powder in the sulphuric liquor, is not only always in the same state as that preci. pitated from acetate of mercury, entirely devoid of inflammability, but contains globules of quicksilver, consequently it must have parted with even more than its excess of oxygen ; and if nitrous gass was present, it would of course seize at least a portion of that oxygen. It is true, that globules of quicksilver may seem incompatible with nitrous acid ; but the quantity of the one may not correspond with that of the other, or the dilution of the acid may destroy its action. " As to the presence of the carbonic acid, it must have arisen either from a complete decomposition of a part of the oxalatr, or admitting the nitrous etherized gass to be a constituent principle of o 3 1QS FULMINATING MliHCl RY. the powder, from a portion of the oxygen, not taken up by the nitrous gass, being united with the carbon of the »-theriz< ry is corroborated by compar. ing the quantity o*' gass estimated to be contained in the fulmi. nating mercury with the qtianties of gass yif-lded from alrohol and nitrous acid, with and without mercury in solution; not to mention that more ether, as well as more gass. is produced with- out the intervention of mercury; and that, according to the Dutch chemists, the product of ether is always in the inverse iati<> to the product of nitrous etherized gass. Should a lurtinr proof be thought necessary to the existence of the nitrous etherized gass, in the fulminating mercury, as well as in the white dense fumes, it may be added, that if a mixture of alcohol and nitrous acid, hold- ing mercury iu solution, be so dilute, and exposed of a tempt ra. ture so low, that neither ether nor nitrous etherized gass an pro. duced, the fulminating mercury, or the white fumes, will n< ver be generated ; for, under such circumstances, the mercury is pre- cipitated chiefly in the state of an inflammable oxalate. Fuither, when we consider the dillerent substances formed li) mi uu on of nitrous acid and alcohol, we are so far acquainted wiih all, < the ether aud the uitrous etherized gass, as to create a pic&ump. 202 FULMINATING MEBCl'RY. tion, that no others arc capable of volatilising mercury, at the very low temperature in which the white fumes t-xist ; since, dur- ing some minutes, they are permanent over water 40° Fahrenheit. *' Hitherto, as much only has been said of the gass which is separated from the mercurial powder, by dilute sulphuric acid, as was necessary to identify it with that into which the same acid can resolve the nitrous etherized gass : I have further to speak of its peculiarity. " The characteristic properties of the inflammable gass seem to me to be the following : 1st. It does not diminish in volume, either with oxygen or nitrous gass. 2dly. It will not explode with oxy. gen, by the electric shock, in a close vessel. 3dly. It burns like hydrocarbonate, but with a blueish-green (lame : and 4thly. It is permanent over water. " It is of course either not formed, or is convertible into nitrous gass by the concentrate nitric and muriatic acids ; because, by those acids, no inflammable gass was extricated from the powder. " Should this inflammable gass prove not to be hydrocarbonate, I shall be disposed to conclude, that it has nitrogen for its basis ; indeed, I am at this moment inclined to that opinion, because I find that Dr. Priestley, during his experiments on his dephlogisti. gated nitrous air, once produced a gass which seems to have re. Sembled this inflammable gass, both in the mode of burning and in the colour of the flame. 11 After the termination of the common solution of iron, in spirit of nitre, he used heat, and got, says he, ' such a kind of air as I had brought nitrous air to be, by exposing it to iron, or liver of sulphur; for, on the first trial, a candle burned in it with a much enlarged flame. At another time, the application of a candle to air produced in this manner, was attended with a real, though not a loud explosion • and immediately after this a green, ish- coloured flame descended from the top to the bottom of the vessel, in which the air was contained. In the next produce of air, from the same process, the flame descended blue, and very rapidly, from the top to the bottom of the vessel.' " These greenish and blue-coloured flames, descending from the top to the bottom of the vessel, are precisely descriptive of the inflammable gass separated from the powder. If it can be pro. FULMINATING MERCURY. 203 ducod with certainty, liy the repetition of Dr. Priestlry's cxpori- nifiits, or should it by any means be got pure from the nitrous etherized gass, my curiosity will excite me to make it the object of future research ; otherwise, I must confess, I shall feel more dis. posed to prosecute othi r chemical subjects : for baring reason to think, that the density of the acid made a variation in the product of this gass, and having never found that any acid, however dense, produced an immediate rxplosion, 1 once poured six drachms of concentrate arid upon fifty grains of the powder. An explosion, nearly at the instant of contact, was effected : I was wounded se- verely, and most of my apparatus destroyed. A quantity more, over of the gass I had previously prepared was lost, by the inad. vertency of a person who went into my laboratory, whilst I was confined by the consequences of this discouraging accident Bat should any one be desirous of giving the gass a further examina- tion. I again repeat, that as far as I am enabled to judge, it may with safety be prepared, by pouring three drachms of sulphuric acid, diluted with the same quantity of water, upon fifty grains of the powder, and then applying the flame of a candle until gass begins to be extricated. The only attempt I have made to decom- pose it, was by exposing it to copper and ammonia ; which, during several weeks, did not effect the least alteration. " I will now conclude (continues Mr. Howard), by observing, that the fulminating mercury seems to be characterised by the fol- lowing properties : " It takes fire at the temperature of 368 Fahrenheit; it ex. plodes by friction, by flint and steel, and by being thrown into concentrate sulphuric acid. It is equally inflammable under the exhausted receiver of an air-pump, as surrounded by atmospheric air ; and it detonates loudly, both by the blow of a hammer, and by a strong electrical shock. " Notwithstanding the compositions of fulminating silver, and of fulminating gold, differ essentially from that of fulminating mercury ; all three have similar qualities. In tremendous effects, silver undoubtedly stands first, and gold perhaps the last. The effects of the mercurial powder, and of gunpowder, admit of little comparison. The one exerts, within certain limits, an almost in- conceivable force : its agents seem to be gass and caloric, very suddenly set at liberty, and both mercury and water thrown into vapour. The other displays a more extended, but inferior power : £04 FULMINATING MERCURY. gass and caloric arc, comparatively speaking, liberated by degrees ; and water, according to count Kumford, is thrown into vapour. " Hence it seems that the fulminating mercury, from the limi- tation of its sphere of action, can seldom, if ever, be applied to mining ; and, from the immensity of its initial force, cannot be used in fire-arms, unless in cases where it becomes an object to destroy them ; and where it is the practice to spike ca.ir; i, it may be of service, because I apprehend it may be used in such a man. ner as to burst cannon, without dispersing any splinters. *' The inflammation of fulminating mercury, by concussion, offers nothing more novel or remarkable than the inflammation, by concussion, of many other substances. The theory of such inllam- inations has been long since exposed by the celebrated Mr. Ber. thollet, and confirmed by Messieurs Fourcroy and Vauquelin : yet, I must confess, I am at a loss to understand why a small quantity of mercurial powder, made to detonate by the hammer or the electric shock, should produce a report so much louder than •when it is inflamed by a match, or by flint and steel. It might at first be imagined, that the loudness of the report could be ac- counted for, by supposing the instant of the inflammation, and that of the powder's confinement, between the hammer and anvil, to be precisely the same ; but, when the electrical shock is sent through or over a few grains of the powder, merely laid on ivory, and a loud report in consequence, I can form no idea of what causes such a report. " The operation by which the powder is prepared, is perhaps one of the most beautiful and surprising in chemistry; and it is not a little interesting to consider the affinities which are brought into play. The superabundant nitrous acid, of the mercurial solu- tion, must first act on the alcohol, and generate ether, nitrous etherized gass, and oxalic acid. The mercury unites to the two last, in their nascent state, and relinquishes fresh nitrous acid, to act upon unaltered alcohol. With respect to the oxalic acid, a predisposing affinity seems exerted in favour of its quantity, as it is evidently not formed fast enough to retain all the mercury ; other, wise, no white fumes during a considerable period of the operation, but fulminating mercury alone will be produced. 11 Should any doubt still l» entertained of the existence of the affinities which have been called predisposing or conspiring, a proof that such affinities really exist, will, I think, be afforded, FULMINATING MERCURY. 205 by comparing the quantity of oxalic acid whirh can be generated from given measures of nitrous acid and alcohol, wilh the inter- vention of mercury, and the intervention of other metals. For instance, when two meai-urnl ounces of alcohol are tr-vated with a solution of 10J gtaiiis of ni(k<-l, in a measured ou.nce and a half of nitrous acid, liltle or no precipitate is produced; yet, by the addition of oxalic acid to (he residuary liquor, a quantity of oxa. late of nickel, after some repose, is deposited. Copper affords another illustration; ICO grains of copper, dissolved in a mea- sured ounce and a half of nitrous acid, and treated with alcohol, yielded me about eighteen grains of oxalate. although cupreous oxalate was plentifully generated, by dropping oxalic acid into the residuary liquor. About twenty-one grains of pure oxalic acid seem to be produced from the same materials, when 100 grains of mercury are interposed. Besides, according to the Dutch paper, more than once referred to, acetous acid is the principal residue after the preparations of nitrous ether. How can we explain the formation of a greater quantity of oxalic acid, from the same materials, with the intervention of 100 grains of mercury, than with the intervention of 100 grains of copper, otherwise than by the notion of conspiring affinities, so analogous to what we see in other phenomena of nature ? " I have attempted, without success, to communicate fulminat- ing properties, by means of alcohol, to gold, platina, antimony, tin, copper, iron, lead, zinc, nickel, bismuth, cobalt, arsenic, and manganese; but I have not yet sufficiently varied my experiments to enable me to speak with absolute certainty. Silver, when twenty grains of it were treated with nearly the same proportions of nitrous acid and alcohol, as 100 grains of mercury, yielded, at the end of the ope. a» ion, about three grains of a grey precipitate, which fulminated with extreme violence. Mr. Cruickshank had the goodness to repeat the experiment : he dissolved forty grains of silver, in two ounces of the strongest nitrous acid, diluted with an equal quantity of water, and obtained (by means of two ounces of alcohol) sixty grains of a very white powder, which fulminated like the grey precipitate above described. It probably combines with the same principles as the mercury, and of course differs from Mr. Berthollet's fulminating silver, before alluded to. I observe, that a white precipitate is always produced in the first instance ; and that it may be preserved by adding water as soon as it i* OQO FULMINATING MERCURY. formed ; otherwise, when the mother liquor is abundant, it often becomes grey, and is re-dissolved." " Several trials of the mercurial powder were afterwards nn 'e at Woolwich, in conjunction with Colonel Bloomfield and Cruickshank, upon heavy guns, carronades, &c. from which Mr. Howard generally infers, that any piece of ordnance mi^ht be destroyed, by employing a quantity of the mercurial powder, equal in weight to one.half of the service-charge of gunpowder ; and, from the seventh and last experiment, we may also conclude, that it would be possible so to proportion the charge of mercurial powder, to the size of different cannons, as to burst them without dispersing any splinters. But the great dang« r attending the use of fulminating mercury, on account of the facility with which it explodes, will probably prevent its being employed for that pur- pose. " In addition to the other singular properties of the fulminatiug mercury (says Mr. Howard), it may be observed, that two ounces, inflamed in the open air, seem to produce a report much louder than when the same quantity is exploded in a gun, capable of re. listing its action. Mr. Cruickshank, who made some of the pow- der by my process, remarked, that it would not inflame gunpow- der. In cousequence of which, we spread a mixture of coarse and fine-grained gunpowder upon a parcel of the mercurial pow- der; and after the inflammation of the latter, we collected most, if not all, of the grains of gunpowder. Can this extraordinary fact be explained by the rapidity of the combustion of fulminating mercury ? Or is it to be supposed (as gunpowder will not explode at the temperature at which mercury is thrown into vapour) that sufficient caloric is not extricated during this combustion ? From thf» late opportunity I have had of conversing with Mr. Cruick. shank, 1 find that he has made many accurate experiments on gun. powder ; and he has permitted me to state, that the matter which remains after the explosion of gunpowder, consists of potass, united with a small proportion of carbonic acid, sulphate of pot- ass, and a very small quantity of sulphuret of potass, and uncon- sumed charcoal. That 100 grains of good gunpowder yielded about fifty-three grains of this residuum, of which three are char- coal. That it is extremely deliquescent, and when exposed to the air, soon absorbs moisture sufficient to dissolve a part of the alkali; in consequence of which the charcoal becomes exposed, NEW DETONATING SUBSTANCE. and the whole assumes a black, or vory dark colour. Mr. Cruick. shanks likewise informs me, that after the combustion of good gunpowder under mercury, no water is ever perceptible." [Pantohg. Phil. Trans. SECTION III. Azotane, or the Detonating Substance of M. Dulong. THIS constitutes one of the latest discoveries in modern chemis- try • and almost all that we know of it in our own country, is through the correspondence and experiments of Sir Humphry Davy. In September 1812, this philosopher received from M. Ampere, then residing at Paris, a letter containing the following passage : " You are doubtless apprised, Sir, of the discovery made at Paris, nearly a year ago, of a combination of azotic gass and calorine, •which has the appearance of an oil, heavier than water, and which detonates with all the violence of the fulminating metals, on the simple heat of the hand ; an effect which has deprived the author of this discovery of an eye and a finger. This detonation takes place by the simple separation of the two gasses, namely the com. bination of oxygen and calorine ; light and heat are largely and equally produced by this detonation, in which a single liquid be. comes decomposed into two gasses *." The farther account of this curious substance we shall give in Sir Humphry's own words, as contained in the Philosophical Trans- actions for 1813. *' The letter," says he, (l contained no account of the mode of preparation of this substance, nor any other details respecting it. So curious and important a result could not fail to interest me, particularly as I have long been engaged in experiments on the action of azote and chlorine, without gaining any decided proofs of their power of combining with each other. I perused with avidity the different French chemical and physical journals, especially Los Annales de Chimie and Le Journal de Physique, of which the complete series of the last year have arrived in this coun. try, in hopes of discovering some detail respecting the prepara- tion of this substance ; but in vain. I was unable to find any thing relative to it in these publications, or in the Moniteur. * " You avez tans doute appr'u," &c, see Phil. Trans, for 1813, p. 1. 208 NEW DF.TONAT1NG SUBSTANCE. " It was evident from ns of nitrate and oxalate. The so uion of prussiate of ammonia acted ott by chlo. rine, afford. «I m •• ol •• peculiar oil ; but produced white fumeg, and became of a right green colour. An attempt was made to procure the substance in large quantities, by passing chlorine into Wolfe's bottles containing the different solutions : but a single trial proved the danger of this mode of operating; the compound had scarcely begun to form, when, by the action of some ammoniacal vapour on chlorine, heat was produced, whica occasioned a violent explosion, and the whole apparatus was destroyed. " I shall now describe the properties of the new substance. Its colour is very nearly that of olive oil, and it is as transparent, and more perfectly liquid. I have not been able to ascertain its speci- fic gravity with accuracy, but it is probably above 16. Its smell is very nauseous^ strongly resembling that of the combination of carbonic oxide aud chlorine, discovered by my brother; and its effect on the eyas is peculiarly pungent and distressing. A little of it was introduced under water into the receiver of an air pump, and the receiver exhausted ; it became an elastic fluid and in its gasseous state was rapidly absorbed or decomposed by the water. When warm water was poured into a glass containing it, it expand- ed into a globule of elastic fluid, of an orange colour, which dimi- nished as it passed through the water. 11 I attempted to collect the products of the explosion of the new substance, by applying the heat of a spirit lamp to a globule of it, confined in a curved glass tube over water : a little gass was at first extricated ; but long before the water had attained tae tem- perature of ebullition, a violent flash of light was perceived, with a sharp report ; the tube and glass were broken into small frag, meais, aud I received a severe wound in the transparent corner of the eye, which has produced a considerable inflammation of the eye, and obliges me to make the communication i;y an amanuensis. This experiment proves what extreme caut a ;s necessary in ope. rating on this substance, for the quantity • used was scarcely as large as a grain of mustard seed. " A small globule of it thrown into a glass of olive oil, produced VOL. vi. * NEW DETONATING SIBStANCfi. a most violent explosion ; and the glass, though strong, was brokfit into fragments. Similar effecls were produced by its action ort oil of turpentine and naphtha. When it was thrown iulo ether, there was a very slight action ; gass was disengaged in small quan- tities, and a substance like wax was formed, which had lost the' characteristic properties of the new body. On alcohol it acted slowly, lost its colour, and became a while oily substance, without explosive powers. When a particle of it was touched under watfr by a particle of phosphorus, a brilliant fight was perceived nndt r the water, and permanent gass was disengaged, having the charac- ters of azote. tl When quantities larger than a grain of mustard seed were used ft>r the contact with phosphorus, the explosion was always so vio. lent as to break the vessel in which the experiment was madr. The new body, when acted upon under water by mercury, afford- ed a substance, having the appearance of corrosive sublimate, and gass was disengaged. On tin foifand zinc it exerted no action ; it had no action on sulphur, nor on resin. In their alcoholic sofuti- ons it disappeared as in pure alcohol. It detonated most violently when thrown into a solution of phosphorus in ether, or in alcoho?. Phosphorus introduced into ether, into which a globule of the sub. stance had been rjfot immediately before, produced no effect. la muriatic acid it gave off gass rapidly, and disappeared without ex- plosion. On dilute sulphuric acid it exerted no violent action. It immediately disappeared without explosion in Libavius's liquor, to which it imparted a yellow tinge. *' It seems probable, from the general tenor of these facts, that the new substance is a compound of azote and chlorine; the same as, or analogous to, that mentioned in the letter from Paris. It is easy to explain its production in our experiments : the hydrogen of the ammonia may Be conceived to combine with one portion of the chlorine to form muriatic acid, and the azote to unite with another portion of chlorine to form the new compound. The heat and light produced during its expansion into gasseous matter, supposing it to be composed of azote and chlorine, is without any parallel in. stance, in our present collection of chemical facts ; the decomposi- tion of euchlorine, which has been compared to it, is mrrrly an expansion of matter already gasseous. The heat and light produced by its rarefaction, in consequence of decomposition, depend, pro. bably, on the same cause as that which produces the flash of light in the discharge of the air gun. DETONATING SUBSTANCE. 211 The mechanical force of (his compound in detonation, seems to be superior to that df any other known, not even excepting the am. moniacal fulminating silver. The Telocity of its action appears to be likewise greater. In a subsequent paper published in the same volume, Sir Hum. phry Davy observes as follows : ** I received in April, a duplicate of the letter in which the dis. corery was announced, containing an Appendix, in which the method of preparing it was described. M. Ampere, my corre- spondent, states that the author obtained it by passing a mixture of azoteand chlorine through aqueous solutions of sulphate, or muriate of ammonia. It is obvious, from this statement that the substance discovered in France, is the same as that which occasioned my acci- dent. The azote cannot be necessary ; for the result is obtained by the exposure of pore chlorine to any common ammoniacal salt* " Since I recovered the use of my eyes, I have made many experi- ments on this compound ; it is probable that most of them have been made before in France ; but as no accounts of the inves- tigations of M. Dulong on (he substance have appeared in any of the foreign journals which have reached this country, and as some difference of opinion and doubts exist respecting its composition, I conceive a few details on its properties and nature will not be entirely devoid of interest." We cannot follow the analysis, whkh is too copious and ope. rose for the present work. The author concludes by observing, that, the compound of chlorine and azote agrees with the com. pounds of the same substance with sulphur, phosphorus, and the metals, in being a non-conductor of electricity ; and these com. pounds are likewise decomposable by heat, though they require that of Voltaic electricity. Sulphur combines only in one proportion with chlorine ; and hence the action of Sulphurane, or Dr.Thompson's muriatic liquor upon water, like that of the new compound, is not a simple phi-no, fiienon of double decomposition. It seems proper to designate this new body by some name : Azotan* •ays Sir Humphry " is the term that would beapplied to it, according to my ideas of its analogy to the other bodies which coniain chlorine ; hut I am not desirous, in the present imperfect and fluctu iting state of chemical nomenclature, to press the adoption of any new word, particularly as applied to a substance out discovered by m)». If." r 2 [Editor, THE GALLERY OF NATURE AND ART. PART II. ART. BOOK II. PYROTECHNY, or the ART of CONSTRUCTING FIRE-IVORKS. CHAPTER I. CONSTRUCTION OF THE CARTRIDGES OF ROCKETS. XX.OCKETS may be regarded as the grand basis of all fire-works, which are little more than modifications of their form, and of the materials of which they usually consist. A rocket is a cartridge or case made of stiff paper, which being filled in part with gun. powder, saltpetre, and charcoal, rises of itself into the air, when fire is applied to it. There are three sorts of rockets : small ones, the calibre of which does not exceed a pound bullet ; that is to say, the orifice of them is equal to the diameter of a leaden bullet which weighs only a pound ; for the calibres, or orifices of the moulds or the models •sed in making rockets, are measured by the diameters of leaden bullets. Middle sized rockets, equal to the size of a ball of from one to three pounds. And large rockets, equal (,o a ball of from three to a hundred pounds. OP ROCKETS. 213 To give the cartridges the same length and thickness, in order that any number of rockets may be prepared of the same size and force, they are put into a hollow cylinder of strong wood, called a mould. This mould is sometimes of metal ; but at any rate it ought to be made of some very hard wood. This mould must not be confounded with another piece of wood, called the former or roller, aruund which is rolled the thick pfper employed to make the cartridge. If the calibre of the mould be divided into 8 equal parts, the diameter of the roller must be equal to 5 of these parts. The vacuity between the roller and the inte- rior surface of the mould, that is to say •£ of the calibre of the mould, will be exactly Ailed by the cartridge. As rockets are made of different sizes, moulds of different lengths and diameters must be provided. The calibre of a cannon is nothing else than the diameter of its mouth ; and we here apply the same term to the diameter of the aperture of the mould. The size of the mould is measured by its calibre ; but the length of the moulds for different rockets does not always bear the same proportion to the calibre, the length bi ing diminished as the calibre is increased. The length of the mould for small rockets ought to be six times the calibre, but for rockets of the mean and larger size, it will be suffi- cient if the length of the mould be five times or four times the calibre of the moulds. At the end of this chapter we shall give two tables, one of which contains the calibres of moulds below a pound bullet ; and the other the calibres from a pound to a hundred pounds bullet. For making the cartridges, large stiff paper is employed. This paper is wrapped round the roller, and then cemented by means of common paste. The thickness of the paper when rolled up in this manner, ought to be about one-eighth and a half of the calibre of the mould, according to the proportion given to the diameter of the roller. But if the diameter of the roller be made equal to £ the calibre of the mould, the thickness of the cartridge must be a twelfth and a half of that calibre. When the cartridge is formed, the roller is drawn out, by turn, ing it round, until it is distant from the edge of the cartridge the length of its diameter. A piece of cord is then made to pass twice round the cartridge at the extremity of the roller. And into the vacuity left in the cartridge, another roller is introduced, so as to some space between the two. On« end of the pack. thread C14 OP ROCKETS. must he fastened to some thinj; fixed, and tlin other to a stick con- veyed between the legs, and placed in such a manner, as to be behind the person who choaks the cartridge. The cord is then to be stretched by retiring backwards, and the cartridge must be pinched until there remains only an aperture capable of admitting the piercer. The cord employed for pinching it is then removed, and hs place is supplied by a piece of pack-thread, which must be drawn very tight, passing it several times round the cartridge, after which it is secured by means of running knots made one above the other. Besides the roller, a rod is used, which being employed to load the cartridge, must be somewhat smaller than the roller, in order that it may be easily introduced into the cartridge. The rod is pierced lengthwise, to a sufficient depth to receire the piercer, which must enter into the mould, and unite with it exactly at its lower part. The piercer, which decreases in size, is introduced into the car. tridge through the part where it has been choaked, and serves to preserve a cavity within it. Its length, besides the nipple or but- ton, must be equal to about two. thirds that of the mould. Lastly, if the thickness of the base be a fourth part of the calibre of the mould, the point must be made equal to a sixth of the calibre. It is evident that there must be at least three rods, pierced in proportion to the diminution of the piercer, in order that the powder which is rammed in by means of a mallet, may be uniformly packed throughout the whole length of the rocket. It may be easily perceived also, that these rods ought to be made of some very hard wood, to resist the strokes of the mallet. In loading rockets, it is more convenient not to employ a piercer. When loaded on a nipple, without a piercer, by means of one massy rod, they are pierced with a bit and a piercer fitted into the end of a bit-brace. Care however must be taken to make this hole suited to the proportion assigned for the diminution of the piercer. That is to say, the extremity of the hole at the choaked part of the cartridge, ought to be about a fourth of the calibre of the mould; and the extremity of the hole which is in the inside for about two. thirds of the length of the rocket ought to be a sixth of the calibre. This hole must pass directly through the middle of the rocket. In short, experience and ingenuity will suggest what is most conve, nient, and in what manner the method of loading rockets, which we shall here explain, may be varied. OF ROCKETS. '21 J After the cartridge is placed in the mould, pour gradually into it the prepared composition ; taking care to pour only two spoon- fuls at a time, ami to rum it immediately down with the rod, strik- ing it in a perpendicular direction with a mallet of a proper size, and giving an equal number of strokes, for example, 3 or 4, each time that a new quantity of the composition is poured in. When the cartridge is about half filled, separate with a bodkin the half of the folds of the paper which remains, and having turned them back on the composition, press them down with the rod and a few strokes of the mallet, in order to compress the paper on the composition. Then pierce three or four holes in the folded paper, by means of a piercer, which must be made to penetrate to ilie composition of the rocket. These holes serve to form a communication between, the body of the rocket and the vacuity at the extremity of the car. tridge, or that part which has been left empty. In small rockets this vacuity is filled with granulated powder, which serves to let them off: they are then covered with paper, and pinched in the same manner as at the other extremity. But in other rockets, the pot containing stars, serpents, and running rockets is adapted to it, as will be shewn hereafter. It may be sufficient however to make, with a bit or piercer, only one hole, which must be neither too large nor too small, such as a fourth part of the diameter of the rocket, to set fire to the powder, taking care that this hole be as straight as possible, and exactly in the middle of the composition. A little of the composition of the rocket must be put into these holes, that the fire may not fail to be communicated to it. It now remains to fix the rocket to its rod, which is done in the following manner. When the rocket has been constructed as above described, make fast to it a rod of light wood, such as fir or willow, broad and flat at the end next the rocket, and decreasing to. wards the other. It must be as straight and free from knots as possible, and ought to be dressed, if necessary, with a plane. Its length and weight must be proportioned to the rocket ; that is to say, it ought to be six, seven, or eight feet long, so as to remain in equilibrium with it, when suspended on the finger, within an inch or an inch and a half of the neck. Before it is fired, place it with the neck downwards, and let it rest on two nails, in a direction perpendicular to the horizon. To make it ascend straighter and to P4 216 OF ROCKETS. a greater height, adapt to its summit a pointed cap or top, mad* of common paper, •which will serve to facilitate its passage through the air. These rockets, in general, are made in a more complex manner, several other things being added to them to render them more agreeable, such for example as a petard, which is a box of tin. plate, filled with fine gunpowder, placed on the summit. The petard is deposited on the composition, at the end where it has been filled ; and the remaining paper of the cartridge is folded down over it to keep it firm. The petard produces its effect when the rocket is in the air and the composition is consumed. Stars, golden rain, serpents, saucissons, and several other amusing things, the composition of which we shall explain here, after, are also added to them. This is done by adjusting to the head of the rocket, an empty pot or cartridge, murh larger thnn the rocket, in order that it may contain serpents, stars, and various ottu-r appendages, to render it more beautiful. Rockets may be made to rise into the air without rods. For this purpose four wings must be attached to them in the form of a cross, and similar to tho«e seen on arrows or darts. In length, these wings must be equal to two-thirds that of the rocket ; their breadth towards the bottom should be half their length, and their thickness ought to be equal to that of a card. But this method of making rockets ascend is less certain, and more inconvenient than that where a rod is used ; and for this rea- son it is rarely employed. We shall now shew the method of finding the diameters or calibre of rockets, according to their weight ; but we must first observe that a pound rocket, ib that just capable of admitting a leaden bullet of a pound weight, and s>o of the rest. The calibre for the different sizes may be found by the two following tables, one of which is calculated for rockets of a pound weight and below ; and tile other for those from a pound weight to 50 pounds. OF ROCKETS. 21 7 I. Talle of the calibre of moulds of a pound weight and . 'onces. Lines. Drams. Lines. 16 191 14 71 12 17 12 7 8 15 10 6-^ 7 14* 8 65 6 144 6 5f 5 13 4 41 4 12-y 2 3| 3 "i 2 4 1 67 The use of (his table will be understood mer ly by inspection ; for it is evident that a rocket of 12 ounces ought to be 17 lines in, diameter ; one of 8 ounces, 15 lines ; one of 10 drams, 6| lines ; •and so of the rest. On the other hand, if the diameter of the rocket be given, it will be easy to find the weight of the ball corresponding to that calibre. For example, if the diameter be 13 lines, it will he immediately seen, by looking for that number in the column of lines, that it cor- responds to a ball of 5 ounces. II. Table of the calibre of moulds from 1 to SO pounds ball. Pounds. Calibre. Pounds. Calibre. Pounds. Calibre Pounds. Calibre. 1 100 14 241 27 300 40 341 2, 126 15 217 28 301 41 344 3 144 16 2/>'2 29 307 42 347 4 158 ' 17 257 30 310 43 350 5 171 ; 18 262 31 314 44 353 6 181 19 267 32 317 45 355 7 191 20 271 33 320 46 358 8 200 21 275 34 323 47 361 9 208 22 280 35 326 48 363 10 215 ! 23 2«4 36 330 49 366 11 222 ' 24 288 37 333 50 368 12 228 25 292 38 336 13 235 26 296 39 339 The use of the second table is as follows : If the weight of the ball be given, which we shall suppose to be 24 pounds, seek for 218 COMPOSITION OF ROCKETS. that number in the column of pounds, and opposite (o it, in the column of calibres, will be found the number 2K8. Then say as 100 is to J9{, so is 288 to a fourth term, which will be the number of lines of the calibre required ; or multiply the number found, that is 288, by 19j, and from the product 56"' 16, cut off the two last figures: the required calibre therefore will be 56-16 lines, or 4 inches 8 lines. On the other hand, the calibre being given in lines, the weight of the ball may be found with equal ease : if the calibre, for example, be 28 lines, say as I0[ is to 28, so is 100 to a fourth term, which •will be 143*5, or nearly 144. But in the above table, opposite to 144, in the second column, will be found the number 3 in the first ; which «hews that a rocket, the diameter or calibre of which is 28 Jiues, is a rocket of a 3 pounds ball. CHAP. II. COMPOSITION OP THE POWDER FOIl ROCKETS, AND THJt MANNER OF FILLING THEM. J. HE composition of the powder for rockets must be different, according to the different sizes ; as that proper for small rockets, •would be too strong for large ones. This is a fact respecting which almost all the makers of fire-works are agreed. The quantities of the ingredients, which experience has shewn to be the best, are as follows : For rockets capable of containing one or tiso ounces of com. position. To one pound of gunpowder, add two ounces of soft charcoal ; or to one pound of gunpowder, a pound of the coarse powder used for cannon ; or to nine ounces of gunpowder, two ounces of char, coal ; or to a pound of gunpowder, an ounce and a half of saltpetre, and as much charcoal. For rockets of tzco or three ounces. To four ounces of gunpowder, add an ounce of charcoal j or to nine ounces of gunpowder, add two ounces of saltpetre. COMPOSITION OF ROCKKTS. For a rocket of four ounces. To four pounds of gunpowder, add a pound of saltpetre, and four ounces of charcoal • you may add also, if you choose, half an ounce of sulphur ; or to one pound two ounces and a half of gun. powder, add four ounces of saltpetre, and two ounces of charcoal ; or to a pound of powder, add four ounces of saltpetre, and one ounce of charcoal ; or to seventeen ounces of gunpowder, add four ounces of saltpetre, and the same quantify of charcoal ; or to three ounces and a half of gunpowder, add ten ounces of saltpetre, and three ounces and a half of charcoal. But the composition will be strongest, if to ten ounces of gunpowder, you add three ounces and a half of saltpetre, and three ounces of charcoal. For rockets of jive or six ounces. To two pounds five ounces of gunpowder, add half a pound of saltpetre, two ounces of sulphur, six ounces of charcoal, and two ounces of iron filings. For rockets of seven or eight ounces. To seventeen ounces of gunpowder, add four ounces of saltpetre, and three ounces of sulphur. For rockets of from eight to ten ounces. To two pounds and five ounces of gunpowder, add half a pound of saltpetre, two ounces of sulphur, seven ounces of charcoal, and three ounces of iron filings. For rockets of from ten to twelve ounces. To seventeen ounces of gunpowder, add four ounces of saltpetre, three ounces and a half of sulphur, and one ounce of chaxcoal. For rockets of from fourteen to fifteen ounces. To two pounds four ounces of gunpowder, add nine ounces of saltpetre, three ounces of sulphur, five ounces of charcoal, and three ounces of iron filings. For rockets of one pound. To one pound of gunpowder, add one ounce of sulphur, and three ounces of charcoal. COMPOSITION OF ROCKETS. for a rocket of two pounds. To one pound four ounces of gunpowder, add two ounces of saltpetre, one onnce of sulphur, three ounces of charcoal, and two ounces of iron filings. For a rocket of three poundt. To thirty ounces of saltpetre, add seven ounces and a half of sulphur, and eleven ounces of charcoal. For rockets of four , five, six, or seven pounds. To thirty. one pounds of saltpetre, add four pounds and a half of sulphur, and ten pounds of charcoal. For rockets of eight, nine, or ten pounds. To eight pounds of saltpetre, add one pound four ounces of sal. phur, and two pounds twelve ounces of charcoal. We shall here observe, that these ingredients must be each pound- ed separately, and sifted ; they are then to be weighed and mixed together for the purpose of loading the cartridges, which ought to be kept ready in the moulds. The cartridges must be made of strong paper, doubled, and cemented by means of strong paste, made of fine flour and very pure water. Of Matches. Before we proceed farther, it will be proper to describe the compo. sition of the matches necessary for letting the rockets off. Take linen, hemp, or cotton thread, and double it eight or ten times, if intend, ed for large rockets ; or only four or five times, if to be employed for stars. When the match has been thus made as large as neces- sary, dip it in pure water, and press it between your hands, to free it from the moisture. Mix some gunpowder with a little water, to reduce it to a sort of paste, and immerse the match in it ; turning and twisting it, rill it has imbibed a sufficient quantity of the pow- der ; then sprinkle over it a little dry powder, or strew some pul. rerised dry powder upon a smooth board, and roll the match over it. By these means you will have an excellent match ; which if dried in the sun, or ou a rope in the shade, will be fit for use. C 221 ] CHAP. III. ON THE CAUSE WHICH M AK ES ROCKETS ASCEND INTO THE AIR. As this cause is nearly the same as that which produces recoil in fire-arms, it is best explained by illustrating the latter. When the powder is suddenly inflamed in the chamber, or at the bottom of the barrel, it necessarily exercises an action two ways at the same time ; that is to say, against the breech of the piece, and against the bullet or wadding, which is placed above it. Besides this, it acts also against the sides of the chamber which it occupies ; and as they oppose a resistance almost insurmountable, the whole effort of the elastic fluid, produced by the inflammation, is exerted in the two dirpctions above mentioned. But the resistance opposed by the bullet, being much less than that opposed by the mass of the barrel or cannon, the bullet is forced out with great velocity. It is impossible, however, that the body of the piece itself should not ex- perience a movement backwards ; for if a spring is suddenly let loose, between two moveable obstacles, it will impel them both, and communicate to them velocities in the inverse ratio of their masses ; the piece therefore must acquire a velocity backwards nearly in the inverse ratio of its mass to that of the bullet. We make use of the term nearly, because there are various circum. stances which give to this ratio certain modifications ; but it is always true that the body of the piece is driven backwards, and that if it weighs with its carriage, a thousand times more than the bullet, it acquires a velocity, which is a thousand times less, and which is soon annihilated by the friction of the wheels against the ground, &c. The cause of the ascent of the rocket is nearly the same. At the moment when the powder begins to inflame, its expansion produces a torrent of elastic fluid, which acts in every direction; that is, against the air which opposes its escape from the cartridge, and against the upper part of the rocket j but the resistance of the air is more considerable than the weight of the rocket, on account of CHINESE AND BRILLIANT FIRE. the extreme rapidity with which the clastic fluid issues through the neck of the rocket to throw itself downwards, and therefore the rocket ascends by the excess of the one of these forces over the other. This howevrr would not be the case, unless the rocket were pierced to a certain depth. A sufficient quantity of elastic lluid •would not be produced ; for the composition would inflame only in circular coats of a diameter equal to that of the rocket j and expe- rience shews that this is not sufficient. Recourse then is had to the very ingenious idea of piercing the rocket with a conical hole, which makes the composition burn in conical strata, which have much greater surface, and therefore produce a much greater quan. tity of inflamed matter and fluid. This expedient was certainly sot the work of a moment. CHAP. IV. BRILLIANT FIRE AND CHINESE FIRE. /\S iron filings, when thrown into the fire, inflame and emit a strong light, this property, discovered no doubt by chance, gave rise to the idea of rendering the fire of rockets much more brilliant, than when gunpowder, or the substances of which it is composed, are alone employed. Nothing is necessary but to take iron filings, very clean and free from rust, and to mix them with the composi. tion of the rocket. It must however be observed, that rockets of this kind will not keep longer than a week ; because the moisture contracted by the saltpetre rusts the iron-filings, and destroys the effect they are intended to produce. But the Chinese have long been in possession of a method of ren- dering this fire much more brilliant and variegated in its colours ; and we are indebted to father d'lncarville, a Jesuit, for having made it known. It consists in the use of a very simple ingredient ; namely, cast iron reduced to a powder more or less fine ; the Chinese gave it a name, which i.s equivalent to that of iron sand. To prepare this sand, take an old iron pot, and having broken it to pieces on an anvil; pulverise the fragments till the grain* are not CHINESE AND BRILLIANT PI&E. 223 larger than radish seed : then sift them through six graduated sieves, to separate the different sizes, and preserve these six dif. ferenl kinds in a very dry place, to secure them from rust, which would render this sand absolutely unfit for the proposed end. We must here remark, that the grains which pass through the closest sieve, are called sand of the first order; those which pass through the next in size, sand of the second order ; and so on. This sand, when it inflames, emits a light exceedingly vivid. It is very surprising to see fragments of this matter no bigger than a poppy seed, form all of a sudden luminous flowers or stars, 12 and 15 lines in diameter. These flowers are also of different forms, according to that of the inflamed grain, and even of different colonrs according to the matters with which the grains are mixed. But rockets into which this composition enters, cannot be long pre- served, as those which contain the finest sand will not keep longer than eight days, and those which contain the coarsest, fifteen. The following tables exhibit the proportions of the different ingredients for rockets of from 12 to 36 pounds. For red Chinese fire. Calibres. Saltpetre. Sulphur. Charcoal. Sandofthe 1st order. Pounds. Pounds. Ounces. Ounces. oz. dr. 12 to li 1 3 4 7 18 to 21 1 3 5 7 8 2i to 3C 1 4 6 8 For zchitc Chinese Jire. Calibres. Pounds. Saltpetre. Pounds. Bruised Gunpowder Ounces. Charcoal, oz. dr. Sandofthe 3d order, oz. dr. 12 to 15 18 to 21 24 to 36 1 1 1 12 11 11 7 8 8 8 8 11 11 8 12 When these materials have been weighed, the saltpetre and char- coal must be three times sifted through a hair sieve, in order that they may be well mixed : the iron sand is then to be moistened with good brandy, to make the sulphur adhere, and they must b« FURNITURE OF ROCKETS. thoroughly incorporated. The sand thni MI!JI' ured must be spread over the mixture of saltpetre and charcoal, and the whole must be mixed together uy spreading it over a taole with a spatula. CHAP. V. OF THE FURNITURE Or ROCKETS. 1 HE upper part of rockets is genernlly furnished with some composition, which taking fire when it has reached to its greatest height, emits a considerable blaze, or produces a loud report, and very often both these together. Of this kind are saucissons, marroons, stars, showers of fire, &c. To make room for this artifice, the rocket is crowned with a part of a greater diameter, called the pot. The method of making this pot, and connecting it with the body of the rocket, is as follows. The mould for forming the pot, though of one piece, must consist of two cylindric parts of different diameters. That on which the pot is rolled up, must be three diameters of the rockets in length, and its diameter must be three fourths that of the rdcket ; the length of the other ought to be equal to two of these diameters, and its diameter to £ that of the rocket. Having rolled the thick paper intended for making the pot, and which ought to be of the same kind as that used for the rocket, twice round the cylinder, a portion of it must be pinched in that part of the cylinder which has the least diameter : this part must be pared in such a manner, as to leav*> only what is necessary for making the pot fast to the top of the rocket, and the ligature must be covered with paper. To charge such a pot, attached to a rocket : having pierced three or four holes in the double paper which covers the vacuity of the rocket, pour over it a small quantity of the composition with which the rocket is filled, aud by shaking it, make a part enter these holes ; then arrange in the pot the composition with which it is to be charged, taking care not to introduce into it a quantity heavier than the body of the rocket. The whole must then be secured by means of a few small balls of sERPENfs. 225 paper, to keep every thing in its place, and the pot must be covered with paper cemented t < < diies : if a pointed summit or cap be then added to it, the rocket will then be ready for use. We shall now givt an account of the different artifices with which such rockets are loaded. SECTION I. Of Serpents. SERPENTS are small flying rockets, without rods, which instead of rising in a perpendicular direction, mount obliquely, and fall back *n a zig-zag form without ascending to a great height. The com- position of them is nearly the same as that of rockets ; and there- fore nothing more is necessary than to determine the proportion and construction of the cartridge, which is as follows. The length of the cartridge may be about 4 inches; it must be rolled round a stick somewhat larger than the barrel of a goose quill, and after being choaked at one of its ends, nil it with the composition a little beyond its middle, and then pinch it so as to leave a small aper- ture. The remainder must be filled with grained powder, which will make a report when it bursts. Lastly, choak the cartridge entirely towards th&extremity ; and at the other extremity place a train of moist powder, to which, if fire be applied, it will be com- municated to the composition, and cause the whole to rise in the air. The serpent, as it falls will make several turns in a zig-zag direction, till the fire is communicated to the grained powder ; on which it will burst with a loud report before it falls to the ground. If the serpent be not choaked towards the middle, instead of moving in a zig-zag direction, it will ascend and descend with an undulating motion, and then burst as before. The cartridges of serpents are generally made with playing cards. > These cards are rolled round a rod of iron or hard wood, a little larger, as already said, than the barrel of a goose quill. To con. fine the card, a piece of strong paper is cemented over it. The length of the mould must be proportioned to that of the cards employed, and the piercer of the nipple must be three or four lines in length. These serpents arc? loaded with bruised pow- der, mixed only with a very small quantity of charcoal. To in. produce the composition into the cartridge, a quill, cut into the VOL. TI. Q MARROONS. — SAL'CISSOWS. form of a spoon, may be employed : it must be rammed down by means of a small rod, to which a few strokes are given with a small mallet. Wheii the serpent is half loaded, instead of pinching it in that part, you may introduce into it a vetch seed, and place granulated powder above it to fill up the remainder. Above this powder place a small pellet of chewed paper, and then choak the other end of the cartridge. If you are desirous of making larger serpents, ce- ment two playing cards together ; and, that they may be managed with more ea.-e, moisten them a little with water. The match con- sists of a paste made of bruised powder, and a small quantity of water. SECTION II. Marroons. MARROONS are small cubical boxes, filled with a composition proper for making them burst, and may be constructed with great ease. Cut a piece of pasteboard, according to the method taught in geometry to form the cube; join these squares at the edges, leaving only one to be cemented, and fill the cavity of the cube with grained powder j then cement strong paper in various directions over this body, and wrap round it two rows of pack-thread, dipped in strong glue ; then make a hole in one of the corners, and introduce into it a match. If you are desirous to have luminous marroons, that is to say maroons which, before they burst in the air, emit a brilliant light, cover them with a paste the composition of which will be given hereafter for stars ; and roll them inr pulverised gunpowder, to serve as a match or communication. SECTION III. Saucissons. M.IBROONS and saucissons differ from each other only in their form. The cartridges of the latter are round, and must be only four times their exterior diameter in length. They are choaked at STARS. «27 one end in the same manner as a rocket; and a pellet of paper is driven into the aperture which has been left, in order to fill it up. They are then charged with grained powder, above which is placed a ball of paper gently pressed down, to prevent the powder from being bruised; the second end of the saucisson being afterwards choaked,. the edges are pared on both sides, and the whole is co. vered with several turns of pack- thread, dipped in strong glue, and then left to dry. When you are desirous of charging them, pierce a hole in one of the ends ; and apply a match, in the same manner as to marroons. SECTION IV. Stars. STARS are small globes of a composition which emits a brilliant light, that may be compared to the light of the stars in the heavens* These balls are not larger than a nutmeg or musket bullet, and when put into the rockets must be wrapped up i i tow, prepared for that purpose. The composition of these stars is as follows. To a pound of fine gunpowder well pulverised, add four pounds of saltpetre, and two pounds of sulphur. When tfiese ingredients are thoroughly incorporated, take about the size of a nutmeg of this mixture, and having wrapt it up in a piece of linen rag, or of paper, form it into a ball ; then tie it closely round with a pack, thread, and pierce a hole through the middle of it, sufficiently large to receive a piece of prepared tow, which will serve as a iratehi This star, when lighted, will exhibit a most beautiful appearance ; besides the fire, as it issues from the two < mis of the hole in the middle, will extend to a greater distance, and make it appear much larger. If you are desirous to employ a moist composition in thp form of a pa^te, instead of a dry one, it will not b«> necessary to wrap up the star in any thing but prepared tow ; because, \\ hi-n made of such paste, if can retain its spherical figure, 'i here will b«> no noed also of piercing a hole in it, to receive the match ; because, •W.IHMI newly made, and consequently moist, it may be rolled in puhe- rised gunpowder, which will adhere to it. This powder, when kindled, will «.erve as a match, and inflame the composition of U»« star, which in falling will form itself into tears. STARS. Another method of making Rockets with Start. Mix three ounces of saltpetre, with one ounce of sulphur, and two drams of pulverised gunpowder; or mix four ounces of sul- phur, with the same quantity of saltpetre, and eight ounces of puL verised gunpowder. When these materials have been well sifted, besprinkle them with brandy, in which a little gum has been dis. solved, and then make up the star in the following manner. Take a rocket mould, eight or nine lines in diameter, and intro- duce into it a nipple, the piercer of which is of a uniform size throughout, and equal in length to the height of the mould. Put into this mould a cartridge, and by means of a pierced rod load it with one of the preceding compositions ; when loaded, take it from the mould, without removing the nipple, the piercer of which passes through the composition, and then cut the cartridge quite round into pieces of the thickness of three or four lines. The cartridge being thus cut, draw out the piercer gently, and the pieces, which resemble the men employed for playing at drafts, pierced through the middle, will be stars, which must be filed on a match thread, which, if you choose, may be covered with tow. To give more brilliancy to stars of this kind, a cartridge thicker than the above dimensions, and thinner than that of a flying-rocket of the same size, may be employed ; but, before it is cut into pieces, five or six holes must be pierced in the circumference of each piece to be cut. When the cartridge is cut, and the pieces have been filled, cement over the composition small bits of card, each having a hole in the middle, so that these holes may correspond to the place where the composition is pierced. REMARKS. 1. There are several other methods of making stars, which it •would be too tedious to describe. We shall therefore only shew how to make ttoiles d pet, or stars which give a report as loud as that of a pistol or musket. Make small saucissons, as taught in the third section ; only, it will not be necessary to cover them with pack-thread : it will be sufficient if they are pierced at one end, in order that you may tie to it a star constructed according to the first method, the composi- tion of which is dry; for if the composition be in the form of a SHOWER OF FIRE. paste, there will be no need to tie it. Nothing will be necessary in that case, but to leave a little more of the paper hollow at the end of the saucisson which has been pierced, for the purpose of intro- ducing tlie composition ; and to place in the vacuity, towards the neck of the saucisson, some grained powder, which will communi. cate fire to the saucisson when the composition is consumed. 2. As there are some stars which in the end become petards, others may be made, which shall conclude with becoming serpents. But this may be so easily conceived and carried into execution, that it would be losing time to enlarge further on the subject. We shall only observe, that these stars are not in use, because it is difficult for a rocket to carry them to a considerable height in the air : they diminish the effect of the rocket or saucisson, and much time is re* quired to make them, SECTION V. Shovaer of Fire. To form a shower of fire, mould small paper cartridges on an iron rod, two lines and a half in diameter, and make them two inches and a half in length. They must not be choaked, as it will be sufficient to twist the end of the cartridge, and having put the rod into it to beat it, in order to make it assume its form. When the cartridges are filled, which is done by immersing them in the composition, fold down the other end, and then apply a match* The furniture will fill the air with an undulating fire. The follow- ing are some of the compositions proper for stars of this kind. Chinese fire. — Pulverised gunpowder one pound, sulphur two ounces, iron sand of the first order five ounces. Ancient Jire.— Pulverised gunpowder one pound, charcoal two ounces. Brilliant fire. — Pulverised gunpowder one pound, iron filings four ounces. The Chinese fire is certainly the most beautiful. 2JO GOLDEN RAIN. SECTION VI. OJ Sparki. SPARKS differ from stars only in their size and duration ; for they are made smaller than stars ; and are consumed sooner. They are made in the following manner. Having put into an earthen vessel an ounce of pulverised gun. powder, two ounces of pulverised saltpetre, one ounce of liquid saltpetre, and four ounces of camphor reduced to a sort of farina, pour over this mixture some gum. water, or brandy in which gum. adraganth or gum-arabic has been dissolved, till the composition acquire the consistence of a thick soup. Then take some lint •which has been boiled in brandy, or in vinegar, or even in salt, petre, and then dried and unravelled, and throw into the mixture such a quantity of it as is sufficient to absorb it entirely, taking care to stir it well. Form this matter into small balls or globes of the size of a pea ; and having dried thf-m in the sun or the shade, besprinkle them •with pulverized gunpowder, in order that they may the mpre rea. dily catch fire. Another Method of making Sparks. Take the saw.dust of any kind of wood that burns readily, such as fir, elder-tree, poplar, laurel, &c. and boil it in water in which saltpetre has been dissolved. When the water has boiled some time, take it from the fire, and pour it off in such a manner that the saw-dust may remain in the vessel. Then place the saw dust on a table, and while moist besprinkle it with sulphur, sifted through a ver) fine sieve : you may add to it also a little bruised gun. powder. Lastly, when the saw.dust has bt-t- n well mixed, leave it to dry, and make it into sparks as above described. t SECTION VIJ. Of Golden Rain. THERE are some flying rockets which, as they fall, make small undulations in the air like hair half frizzled. These are called fusfes chevelues, bearded rockets; they tiuish with a kind of COURANTINS. 231 shower of fire, which is called golden rain. The method of con- structing them is as follows. Fill the barrels of some goose quills with the composition of fly. ing-rockets, and place upon the mouth of each a little moist gun- powder, both to keep in the composition, and to serve as a match. If a flying-rocket be then loaded with these quills, they will pro. duce, at the end, a very agreeable shower of fire, which on account £>f its beauty has been called golden rain. CHAP. VI. SOME ROCKETS DIFFERENT IN THEIR EFFECT FROM COMMON ROCKETS. very amusing and ingenious works are made by mean of simple rockets, of which it is necessary that we should here give the reader some idea. SECTION I. Of Courantintj or Rockets which Jly along a Rope. A COMMON rocket, which however ought not to be very large, may be made to run along an extended rope. For this purpose, affix to the rocket an empty cartridge, and introduce into it the rope which is to carry it ; placing the head of the rocket towards that side on which you intend it to move : if you then set fire to the rocket, adjusted in this manner, it will run along the rope without stopping, till the matter it contains is entirely exhausted. If you are desirous that the rocket should move in a retrograde direction ; first till one half of it with the composition, and cover it •with a small round piece of wood, to serve as a partition between it and that put into the other half; then make a hole below this par. tition, so as to correspond with a small canal filled with bruised powder, and terminating at the other i nd of the rocket : by these means the fire, when it ceases in the first half of the rocket, will be communicated through the hole into the small canal, which will • 4 WATER ROCKETS. convoy it to (he other end ; and this end being then kindled, the rocket will move backwards, and return to the place from which it Ml out. Two rockets of equal size, bound together by means of a piece of strong pack-thread, and disposed in such a manner that the head of the one shall be opposite to the neck of the other, that when the fire has consumed the composition in the one, it may be communi. cated to that in the other, and oblige both of them to move iu a re. trograde direction, may also be adjusted to the rope by means of a piece of hollow reed. But to prevent the fire of the former from being communicated to the second too soou, they ought to be co- vered with oil-cloth, or to be wrapped up in paper, REMARK. Rockets of this kind are generally employed for setting fire to various other pieces when large fireworks are exhibited j and to render them more agreeable, they are made in the form of different animals, such as serpents, dragons, &c. ; on which account they are cattcdjlying dragons. These dragons are very amu>ing, espe. cially when filled with various compositions, such as golden rain, long hair, &c. They might be made to discharge serpents from their moutlis, which would produce a very pleasing effect, and give them a greater resemblance to a dragon. SECTION II. Rockets zshtch Jly along a Rope, and turn round at the same time. NOTHING is easier than to give to a rocket of this kind a rotary motion around the rope along which it advances; it will be- sufii. cient for this purpose, to tie it to another rocket, placed in a trans* versal direction. But the aperture of the latter, instead of being at the bottom, ought to be in the side, near one of the ends. If both rockets be fired at the same time, the latter will make the other revolve* around the rope, while it advances along it. SECTION III. Of Rockets zohich burn in the Water. THOUGH fire and water are two things of a very opposite nature, tne rockets above described, when set on fire, will burn and pro. WATER ROCKETS. 233 duce their effect even in the water; but a« they are then brlow the water, the pleasure of seeing then- is lost ; for thi- reason, • hen it is required to cause rockets to burn as th< y float on the water, it wiil be necessary to make >oniO change in the proportions of the moulds, and the materi; s of which they are composed. In regard to the mould, i • my be eight or nine inches in length, and an inch in diameter: the form* r, on which the cartridge is rolled up, may be nine lines in thickness, and th>- rod for loading the cartridge must as usual be soim what less. For loading the cartridge, there is no need 'or a pifn'* r \\^';< \ nipple. The composition nr-iy l>e maJe ii rw vvaj - } for if it be required that the rocket, while burning on the water, should appear as bright as a candle, it must be composed of three materials mixed together, viz. three ounces of pulverised and sifted gunpowder, one pound of saltpetre, and eight ounces of sulphur. But if you are desirous that it should appear on the water with a beautiful tail, the composition must consist of eight ounces of gunpowder pulverised and sifted, one pound of saltpetre, eight ounces of pounded and sifted sulphur, and two ounces of charcoal. When the composition has been prepared according to these pro. portions, and the rocket has been tilled in the manner above de. scribed, apply a saticisson to the end of it ; and having covered the rock< i with wax, black pitch, resin, or any other substance ca. pable of preventing the paper from being spoilt d in the water, attach to it a small rod ot white willow, about two feet in length, that the rocket may conveniently float. If it be required that these rockets should plunge down, and again rise up ; a certain quantity of pulverised gunpowder, with, out any mixture, must be introduced into them, at certain dis- tances, such for example, as two, three, or four lines, according to the size of the cartridge. REMARKS. 1. Small rockets of this kind maybe made, without changing the mould or composition, in several different ways, which, for the sake of brevity, we are obliged to omit. Such of our readers as are desirous of further information on this subject, may consult those authors who have written expressly on pyrotechny, some of whom we shall mention at the end of this book. 2. It is possible also to make a rocket which) after it has burnt 234 ROCKETS TO REPIIESENT FIGURES IN THE AIR. some time on the water, shall throw out sparks and stars ; and these after they catch fire shall ascend into the air. This may be done by dividing the rocket into two parts, by means of a round piece of wood, having a hole in the middle. The upper part must be filled with the usual composition of rockets, :ind the lower with stars, which must be mixed with grained and pulverised gun. powder, &c. 3. A rocket which takes fire in the water, and, after burning there half the time of its duration, mounts into the air with great Telocity, may be constructed in the following manner. Take a flying rocket, furnished with its rod, and by means of a little glue attach it to a water rocket, but only at the middle, in such a manner, that the latter shall have its neck uppermost, and the other its neck downward. Adjust to their extremity a small tube, to communicate the fire from the one end to the other, and cover both with a coating of pitch, wax, &c. that they may not be damaged by the water. Then attach to the flying rocket, after it has been thus cemented to the aquatic one, a rod of the kind described in the second ar. tide ; and suspend a piece of pack-thread, to support a musket bullet made fast to the rod by means of a needle or bit of iron •wire. When these arrangements have been made, set fire to the part after the rocket is in the water; and when the composition is consumed, the fire will be communicated through the small tube to the other rocket : the latter will then rise and leave the other, which will not be able to follow it on account of the \yeight ad* Jjcring to it, SECTION IV. By means of Rockets, to represent several figures in the Air. IF several small rockets be placed upon a large one, their rods being fixed around the large cartridge, which is usually attached to the head of the rocket, to contain what it is destined to carry up into the air ; and if these small rockets be set on fire while the large one is ascending, they will represent, in a very agreeable manner, a tree, the trunk of which will be the large rocket, and the branches the small ones. If these small rockets take fire when the large one is half burned in the air, they will represent a comet j and when the large oiie in GLOBES AND BALLS. 235 entirely inverted, so that its head begins to point downwards, in order to fall, they will represent a kiinl of fiery fountain. If the barrels of several quills, filled with the composition of flying rockets, as above described, be placed on a lar_,e rocket ; when thrse quills catch fire, they will represent, to an eye placed below them, a beautiful shower of fire, or of half frizzled hair, if the eye be placed on one side. If several serpents be attached to the rocket with a piece of pack-thread, by the ends that do not catch fire; and if the pack- thread be suffered to hang down two or three inches, between every two, this arrangement will produce a variety of agreeable and, amusing figures, SECTION V. A Rocket zchich ascends in the Form of a Screw. A STRAIGHT rod, as experience shews, makes a rocket ascend perpendicularly, and in a -traight line : it may be compared to the rudder of a ship, or the tail of a bird, the effect of which is to make the vessel or bird turn towards that side to which it is inclined: if a bent rod therefore be attached to a rocket, its first effect will be to make the rocket incl ne towards that side to which it is bent; but its centre of gravity bringing it afterwards into a vertical situ, ation, the result of these two opposite efforts will be that the rocket •will ascend in a zig.z »g or spiral form. In this case indeed, as it displaces a greater volume of air, and describes a longer line, it will not ascend so high, as if it had been impelled in a straight di. rection ; but, on account of the singularity of this motion, it will produce an agreeable effect. CHAP. VII. OF GLOBES AND FIRE BALLS. W E have hitherto spoken only of rockets, and the different kindi of works which can be constructed by their means. But there are a great many other fireworks, the most remarkable of which we 236 WATER GLOBES. shall here describe. Among these are globes and fire balls ; some of which are intended to produce their effect in water ; others by rolling or leaping on the ground ; and some, which are called bombs, do the same in the air. SECTION I. Globes which burn on the Water. THESE globes, or fire balls, are made in three different forms ; spherical, spheroidal, or cylindrical ; but we shall here confine ourselves to the spherical. To make a spherical fire ball, construct a hollow wooden globe of any size at pleasure, and very round both within and without, so that its thickness may be equal to about the ninth part of the diameter. Insert in the upper part of it a right concave cylinder, the breadth of which may be equal to the fifth part of the diameter ; and having an aperture equal to the thickness, that is, to the ninth part of the diameter. It is through this aperture that the fire is communicated to the globe, when it has been filled with the proper Composition, through the lower aperture. A petard of metal, loaded with good grained powder, is to be introduced also through the lower aperture, and to be placed horizontally. When this is done, close up the aperture, which is nearly equal to the thickness of the cylinder, by means of a wooden tompion dipped in warm pitch ; and melt over it such a quantity of lead that its weight may cause the globe to sink in water ; which will be the case if the weight of the lead, with that of the globe and the composition, be equal to the weight of an equal volume of water. If the globe be then placed in the water, the lead by its gravity will make the aperture tend directly downwards, and keep in a perpen- dicular direction the cylinder, to which fire must have been pre- viously applied. To ascertain whether the lead, which has been added to the globe, renders its weight equal to that of an equal volume of water, rub the globe over with pitch or grease, and make a trial, by placing it in the water. The composition with which the globe must be loaded, is as follows: to a pound of grained powder, add 32 pounds of salt, pttrc reduced to fine flour, 8 pounds of sulphur, 1 ouuce of scrapings GLOBES AND BALLS. 237 of ivory, and 8 pounds of saw-dust previously boiled in a solution of saltpetre, and dried in the shade, or in the sun. Or, to 2 pounds of bruised gunpowder, add 12 pounds of salt- petre, 6 pounds of sulphur, 4 pounds of iron filings, ind 1 pound of Greek pitch. It is not necessary that this composition should be beaten so fine as that intended for rockets : it requires neither to be pulverised nor sifted ; it is sufficient to be well mixed and incorporated. But to prerent it from becoming too dry, it will be proper to besprinkle it with a little oil, or any other liquid susceptible of inflammation. SECTION II. Of Globes which leap or roll on the Ground* 1. HAVING constructed a wooden globe with a cylinder, similar to that above described, and having loaded it with the same com. position, introduce into it four petards, or even more, loaded with good grained gunpowder to their orifices, which must be well stop- ped with paper or tow. If a globe, prepared in this manner, be fired by means of a match, it will leap about, as it burns, on a smooth horizontal plane, according as the petards are set on fire. Instead of placing these petards in the inside, they may be affixed to the exterior surface of the globe ; which they will make to roll and leap as they catch fire. They may be applied in any manner to the surface of the globe. 2. A similar globe may be made to roll about on a horizontal plane, with a very rapid motion. Construct two equal hemispheres of pasteboard, and adjust in one of them three common rockets filled and pierced like flying rockets that have no petard : these rockets must not exceed the interior breadth of the hemisphere, and ought to be arranged in such a manner, that the head of the one shall correspond to the tail of the other. The rockets being thus arranged, join the two hemispheres, by cementing them together with strong paper, in such a manner that they shall not separate, while the globe is moving and turning, at the same time that the rockets produce their effect. To set fire to the first, make a hole in the globe opposite to the tail of it, and in. troduce into it a match. This match will communicate fire to the first rocket j which, when consumed, will set fire to the second by means of another match, and so on to the rest ; so that the globe, 838 AERIAL GLOBKS. if placed on a smooth horizontal plane, will be kept in continual motion. It is here to be observed, that a few more holes must be made in the globe, otherwise it will burst. The two hemispheres of pasteboard may be prepared in the fol- lowing manner : construct a very round globe of solid wood, and cover it with melted wax ; then cement over it several bands of coarse paper, about two inches in breadth, giving it several coats of this kind, to the thickness of about two lines. Or, what will be still easier and better, having dissolved, in glue water, some of the pulp employed by the paper makers, cover with it the surface of the globe ; then dry it gradually at a slow fire, and cut it through in the middle ; by which means you will have two strong hemi. spheres. The wooden globe mav.be easily separated from the paste- board by means of heat; for if the whole be applied to a strong fire the wax will dissolve, so that the globe may be drawn out. Instead of melted wax, soap may be employed. SECTION III. Of Aerial Globes, called Bombs. THESE globes are called aerial, because they are thrown into the air from a mortar, which is a short thick piece of artillery of a Jarge calibre. Though those globes are of wood, and have a suitable thickness, namely, equal to the twelfth part of their diameters, if too much powder be put into the mortar, they will not be able to resist its force ; the charge of powder therefore must be proportioned to the globe to be ejected. The usual quantity is an ounce of powder for a globe of four pounds weight ; two ounces for one of eight, and so on. As the chamber of the mortar may be too large to contain the exact quantity of powder sufficient for the fire ball, which ought to be placed immediately above the powder, in order that it may be expelled and set on fire at the same time, another mortar may be constructed of wood, or of pasteboard with a wooden bot- tom : it ought to be put into a large iron mortar, and to be loaded with .1 quantity of powder proportioned to the weight of the globe. This small mortar roust be of light wood, or of paper pasted to. getber, and rolled up iu the form of a cylinder, or truncated cone, AERIAL OLOBF.S. 239 the bottom excepted ; which, as already said, must be of wood. The chamber for the powder must be pierced obliquely, with a small gimblet ; so that the aperture corresponding to the aperture of the metal mortal, the fire applied to the latter may be communi. cated to the powder which is at the bottom of the chamber, imme- diately below the globe. By these means the globe will catch fire, and make an agreeable noise as it rises into the air ; but it would not succeed so well, if any vacuity were left between the powder and the globe. A profile or perpendicular section of such a globe is represented by the right-angled parallelogram, the breadth of which is nearly equal to the height. The thickness of the wood, towards the two sides, is equal, as above said, to the twelfth part of the diameter of the globe ; and the thickness of the cover is double the preceding, or equal to a sixth part of the diameter. The height of the cham- ber, where the match is applied, and which is terminated by a semi- circle, is equal to the fourth part of the breadth ; and its breadth is equal to the sixth part. We must here observe that it is dangerous to put wooden covers on aerial balloons or globes ; for these coters may be so heavy, as to wound those on whom they happen to fall. It will be sufficient to place turf or hay above the globe, in order that the powder may experience some resistance. The globe must be filled with several pieces of cane or common reed, equal in length to the interior height of the globe, and charged with a slow composition, made of three ounces of pounded gun* powder, an ounce of sulphur moistened with a small quantity of petroleum oil, and two ounces of charcoal ; and in order that these reeds or canes may catch fire sooner, and with more facility, they must be charged at the lower ends, which rest on the bottom of the globe, with pulverised gunpowder moistened in the same manner tvith petroleum oil, or well besprinkled with brandy, and then dried. The bottom of the globe ought to be covered with a little gun- powder half pulverised and half grained ; which, when stt on fire, by means of a match applied to the end of the chamber, will set fire to the lower part of the reed. But care must have b«-en taken to fill the chamber with a composition similar to that in the reeds, or with another slow composition, made of eight ounces of gun- t»40 JETS OF FIRE. powder, four ounces of saltpetre, two ounces of sulphur, and one ounce of charcoal : the whole must be well pounded and mixed. Instead of roods, the globe may be charged with running rockets, or paper petards, and a quantity of fiery stars or sparks mixed with pulverised gunpowder, placed without any order above these pe. tards, which must be choaked at unequal heights, that they may perform their effect at different times. These globes may be constructed in various other ways, which it would be tedious here to enumerate. We shall only observe, that when loaded, they must be well covered at the (op ; they must be wrapped up in a piece of cloth dipped in glue, and a piece of woollen cloth must be tied round them, so as to cover the hole which contains the match. CHAP. VIII. JETS OF FIRE. JETS of fire are a kind of fixed rockets, the effect of which is to throw up into the air jets of fire, similar to jets of water. They serve also to represent cascades ; for if a series of such rockets be placed horizontally on the same line, it maybe easily seen that the fire they emit, will resemble a sheet of water. When arranged in a circular form, like the radii of a circle, they form what is called a fixed sun. To form jets of this kind, the cartridge for brilliant fires must, in thickness, be equal to a fourth part of the diameter, and for Chinese fire; only to a sixth part. The cartridge is loaded on a nipple, having a point equal in length to the same diameter, and in thickness to a fourth part of it ; but as it generally happens that the mouth of the jet becomes larger than is necessary for the effect of the fire, you must begin to charge the cartridge, as the Chinese do, by filling it to a height equal to a fourth part of the diameter with clay, which must be rammed down as if it were gunpowder. By these means the jet will ascend much higher. When the charge is completed with the composi- JETS OP FIRE. 241 tion you have made choice of, the cartridge must be closed with a fompion of wood, above which it must be choaked. The train or match must be of the same composition as that cm. ployed for loading ; otherwise the dilatation of the air contained iu the hole made by the piercer, would cause the jet to burst. Clayed rockets may be pierced with two holes near the neck, in «rder to hate three jets in the same plane. If a kind of top, pierced with a number of holes, be added to them, they will imitate a bubbling fountain. Jets intended for representing sheets of fire ought not to be choaked. They must be placed in a horizontal position, or in. clined a little downwards. It appears to us that they might be choaked so as to form a kind of slit, and be pierced in the same manner ; which would contri- bute to extend the sheet of fire still farther. A kind of long nar- row mouth might even be provided for this particular purpose. PRINCIPAL COMPOSITIONS FOR JETS OF FIRE. 1st. Jets of Jive lines or less, of interior diameter. Chinese Jire. — Saltpetre 1 pound, pulverised gunpowder 1 pound, sulphur, 8 ounces, charcoal 2 ounces. White Jire. — Saltpetre 1 pound, pulverised gunpowdrr 8 ounces, sulphur 3 ounces, charcoal 2 ounces, iron sand of the first order 8 ounces. 2d. Jets of from ten to t&elve lines in diameter. Brilliant Jire. — Pulverised gunpowder 1 pound, iron-filings of a mean size, 5 ounces. White Jire. — Saltpetre 1 pound, pulverised gunpowder 1 pound, sulphur 8 ounces, charcoal 1 ounces. Chinese Jire.— Saltpetre 1 pound 4 ounces, sulphur 5 ounces, sand of the third order 12 ounces. 3d. Jett ofjifteen or eighteen line» in diameter. Chinese fire.— Saltpetre 1 pound 4 ounces, sulphur 7 ounces, charcoal 5 ounces, of the six different kinds of sand mixed 12 ounces. Fere d'Incarville, in his memoirs on this subject, gives various other proportions for the composition of these jets ; but w« must VOL. IT. E FIRES OF DIFFERENT COLOURS. confine ourselves (o what has been here said, and refer the reader to the author's memoirs, which will be found in the Manuel de VArtifider. The saltpetre, pulverised gunpowder, and charcoal, are three times sifted through a hair sieve. The iron sand is besprinkled with sulphur, after being moistened with a little brandy, that (he sulphur may adhere to it; and they are then mixed together : the sulphured sand is then spread over the 6rst mixture, and the whole is mixed with a ladle only ; for if a sieve were employed, it would separate the sand from the other materials. When sand larger thau that of the second order is used, the composition is moistened with brandy, so that it forms itself into balls, and the jets are then loaded ; if there were too much moisture, the sand would not per. form its effect. SECTION T. Of Fires of different Colours. IT is much to be wished that, for the sake of variety, different co. lours could be given to these fireworks at pleasure ; but though we are acquainted with several materials which communicate to flame various colours, it has hitherto been possible to introduce only a very few colours into that of inflamed gunpowder. To make white fire, the gunpowder must be mixed with iron or rather steel filings. To make red fire, iron sand of the first order must be employed in the same manner. As copper filings, when thrown into a flame, render it green, it might be concluded, that if mixed with gunpowder, it would pro. duce a green flame; but this experiment does not succeed. It is supposed that the flame is too ardent, and consumes the inflam- mable part of the copper too soon. But it is probable that a suffi- cient number of trials have not yet been made; for is it not possible to lessen the force of gunpowder in a considerable degree, by in. creasing the dose of the charcoal ? However, the following are a few of those materials which, in books on pyrotechny, are said to possess the property of commit, nicating various colours to fireworks. Camphor mixed with the composition, makes the flame to appear of a pale white colour. PASTE FOR DEVICES IN FIRE. 243 Raspings of ivory give a clear flame of a silver colour, inclining a little to that of lead ; or rather a white dazzling flame. Greek pitch produces a reddish flame, of a bronze colour. Black pitch, a dusky flame, like a thick smoke, which obscures the atmosphere. Sulphur, mixed in a moderate quantity, makes the flame appear blueish. Sal ammoniac and verdigris give a greenish flame. Raspings of yellow amber communicate to the flame a lemon colour. Crude antimony gives a russet colour. Borax ought to produce a blue flame; for spirit of wine, in which sedative salt, one of the component parts of borax, is dissolved by the means of heat, burns with a beautiful green flame, Much, however, still remains to be done in regard to this sub- ject; but it would add to the beauty of artificial fireworks, if they could be varied by giving them different colours : this would be cceatiug for the eyes a new pleasure. SECTION II. Composition of a Paste proper for representing Animals, and other Devices in Fire. IT is to the Chinese also that we are indebted for this method of representing figures with fire. For this purpose, take sulphur reduced to an impalpable powder, and having formed it into a paste with starch, cover with it the figure you are desirous of representing on fire : it is here to be observed, that the figure must first be coated over with clay, to prevent it from being burnt. When the figure has been covered with this paste, besprinkle it while still moist with pulverised gunpowder ; and when the whole is perfectly dry, arrange some small matches on the principal parts of it, tliat the tire may be speedily communicated to it on all sides. The same paste may be employed on figures of clay, to form de- vices and various designs. Thus, for example, festoons, garlands, and other ornaments, the flowers of which might be imitated by fire of different colours, could be formed on the frieze of a piece of »r. - ture covered with plaster. The Chinese imitate grapes ex. R * STJN3. ceedingly well, by mixing pounded sulphur with the pulp of the jujube, instead of Hour paste. SECTION in. Of Suns, both fixed and moveablt. NONE of the pyrotechnic inventions can be employed with so much success, in artificial fireworks, as suns ; of which there are two kinds, fixed and revolving : the method of constructing both is very simple. For fixed suns, cause to be constructed a round piece of wood, into the circumference of which can be screwed twelve or fifteen: pieces in the form of radii > and to these radii attach jets of fire, the composition of which has been already described ; so that they may appear as radii tending to the same contre, the mouth of the jet being towards the circumference. Apply a match in such a manner, that the fire communicated at the centre may be conveyed, at the same time, to the mouth of each of (he jets ; by which means, each throwing out its fire, there will be produced the appearance of a radiating sun. We here suppose that the wheel is placed in a position perpendicular to the horizon. These rockets or jets may be so arranged as to cross each other in an angular manner ; in which case, instead of a sun, you will have a star, or a sort of cross resembling that of Malta. Some of these suns are made also with several rows of jets; these are called glories. Revolving suns may be constructed in this manner. Provide a wooden wheel, of any size at pleasure, and brought into perfect equilibrium around its centre, in order that the least effort may make it turn round. Attach to the circumference of it fire-jets placed in the direction of the circumference ; they must not be choaked at the bottom, and ought to be arranged in such a manner, that the mouth of the one shall be near the bottom of the other, so that when the fire of the one is ended, it may immediately proceed to another. It may easily be perceived, that when fire is applied to one of these jets, the recoil of the rocket will make the wheel turn round, unless it be too large and ponderous : for this reason, when these suns are of a considerable size, that is when they con- sist for example of twenty rockets, fire must be communicated at th« same time to the first, the sixth, the eleventh, and the sixteenth ; SUNS. 215 from which it will proceed to the second, the seventh, the twelfth, the seventeenth, and so on. These four rockets will make the wheel turn round with rapidity. If two similar suns be placed one behind the other, and made to turn in a contrary direction, they will produce a very pretty effect of cross.tire. Three or four suns, with horizontal axes passed through them, might be implanted in a vertical axis, moveable in the middle of a table. These suns, revolving around the table, will seem to pur. cue each other. It may be easily perceived that, to make them turn around the table they must be fixed on their axes, and these axes, at the place where they rest on the table, ought to be furnished with a very moveable roller. [Montuela's Ozanan. Frezier Traite det Feux d'Arti- fice. Perrinet d'Orone. Manuel de I'Arti/icier. The attention which has lately been paid to the amusing subject of pyrotechny in this metropolis, in the course of the public fire, works exhibited with so much spirit, and upon so extensive a scale, in the royal parks, has made us fuller in this department than per. haps we otherwise should have been. We believe there is scarcely a device which Mr. Congreve has exhibited, that we have not ex- plained. (Editor. THE GALLERY OF NATURE AND ART. PART II, A R T. BOOK III. Of METALLURGY, and the ARTS connected loith it. WAVING in the preceding part of this work treated of minera- logy, and metallic mines, we shall devote the present book to a few examples of the curious modes of working and mixing metals, and the most important uses to which they are applied: CHAP. I. OF CALAMINE, BLENDE OR BLACK JACK, ZINC, AND BRASS. 1 HE two principal ores of zinc are calamine and blende. The Arabic word climia, or, as it is pronounced by some, calimia, denotes the same substance which we call lapis calaminuris, cala. mine, or calamy ; and hence Salmasius is of opinion, that they judge very preposterously who would derive calamine from calaem, an Indian word signifying, according to him, a species of metal METALLURGY. 247 * resembling tin, which is dug near Malacca*. With due deference to his authority, I would observe, that Indian calaem is not like tin. Many years ago the Dutch took a Portuguese vessel which was laden with calaemt ; and from all the experiments which were made upon that substance, it appeared to be zinc, or that metallic substance which we in Europe have very lately learned the method of extracting from calamine. Both calamine and zinc have the property of changing copper to a yellow colour; and this is the most distinguishing property of them both; it is that for which they are both sought after in commerce : and as climia and calaem have the same radical letters, and denote in the Arabic and Indian languages two substances which agree in one of their most charac- teristic properties, I leave it to others to determine whether they are not the same word, and in which of the two languages that word was originally formed. The other ore of zinc is called by the Germans blende, from its blinding or misleading appearance ; it looking like an ore of lead, but yielding (as was formerly thought) no metallic substance of any kind*. A particular sort of lead ore has been called by Pliny, galena, from a Gre» k word signifying to shine, because it is composed of shining particles; our potters ore and the Derbyshire lead ore are of this sort : blende much resembles galena; but, yielding no lead, it has been called false or pseudo. galena, or mock- lead: our English miners have called it blackjack, and that is the name by which it is known to the makers of brass. Blackjack resembles lead ore so much, that the miners sometimes succeed in selling, to inexperienced smelter*, blackjack instead of lead ore : 1 have heard of the fraud being carried to BO great an extent in Derbyshire, that from a ton of ore * Cadmia Arabihus dicitur climia, quod qiiidam pronunciarunt calimia, unde Grace is rccentioribus xfAt/uia interdum scribiiur, unde nostris Gallis calami na Ct lapis calami naris : qua in vocem quidaro praepostere deducunt ab Indico ca- laem, quod metalli genus est stanno simile, baud longc ex Malacca erui ioli- tum. Salm. de Homony. Hy. lat. C. CXII. t Savotns de Num. P. II. C. XIV. \ PseuJo-palena nomen suum exinde acquisivit, quod faciem quasi miner* plumbeae prae se feral, sed mentiatur, cum id revere non cuntineat quod ex- (erno aspectu pollicelur. Germania appcllatur blende, a blenden j quia, cum falso speciem miners saturnine prae se fcrt, exinde oculos fa-cinei, vel iis imponat. Pott de Pseudo-galena, p. 106. — They nave in Staffordshire a »ort of iron, which they call blende-metal, of which they make nailr, hammers, Arc. Plot's Staff. R4 €48 METALLURGY. there was not obtained above a few ounces of lead ; though a ton of unadulterated lead ore yields in Derbyshire, at an average, fourteen or fifteen hundred weight of lead. Calainiue is found in most parts of Europe ; we have great plenty of it in Somersetshire, Flintshire, Derbyshire, and in many other parts of England. It is scarcely to be distinguished by its appearance from some sorts of lime-stone; for it has none of the metallic lustre usually appertaining to ores : it differs, however, by its weight from every sort of stone; it being, bulk for bulk, near twice as heavy as either flint or limestone. Before the reign of Elizabeth, this mineral was held in very little estimation in Great Britain ; and even at so late a period as towards the end of the 17th century, it was commonly carried out of the kingdom as ballast by the ships which traded to foreign parts, especially to Holland.* It use is now as perfectly understood in England, as in any part of the world ; and as we have greater plenty of cula- minu, and that of a better sort, than most other nations have, there is no fear of our losing the advantages in this article of trade which we are now possessed of. Great quantities of caiauiin^ nave of late years been dug in Der- byshire, on a spot callfd liousale Moor, in the neighbourhood of Alatlock. A bed of iron stone, about four fett in thickness lies over ti.e calamine ; and the calumine is much mixed not only with this iron stone, but with cawk, lead ore, and limestone. The calamiue miners never wibh to meet with lead ore; they say that it eats up the calamine: and tli<> lead miners in return never wish to meet with calamine in a rich vein of lead ore, since they are persuaded that it injures the quality of the ore. It would In- too much to infer, from these observations of the miners, that one of these substances arises from the natural decomposition of the other. Juxtaposition of substances in the bowels of the earth, is no cer- tain proof of their being derived from each other : for no one will contend that chert is derived from the limestone in which it is bedded, or flint and pyrites from the chalk in which they are found ; yet when a great variety of substances are found mixed together in the same little lump, the mind cannot help conjecturing that a more improved state of mineralogy will shew some connection in their origin. I have often seen calamine, and blackjack, and lead » Essay on Metal: Wordi by Sir J. Petty, and Phil. Trans, for 1694. METALLURGY. 249 ore — and cawk, blackjack, and lead ore, bedded together in the same piece of spar. The calamine annually raised in Derbyshire, amounts to about 1500 tons. Sixty years ago (as I was informed by an intelligent dealer in calamine, whose father was one of the first who dug it in that country), they did not raise forty tons in a year. The Derbyshire calamine does not bear so good a price as that which is gotten about Mendip in Somersetshire ; the former being sold for about forty shillings, and the latter for sixty-five or seventy shil- lings a ton, before dressing : when thoroughly dressed, the Derby, shire calamine may be bought for about six guineas, and the other for eight pounds, a ton. This dressing of the calamine consists, principally, in picking out all the pieces of lead ore, limestone, iron stone, cawk, and other heterogeneous substances which are mixed with it, when it is first dug from the mine ; this picked cala. mine is then calcined in proper furnaces, and by calcination it loses between a third and a fourth of its weight. The substance which is lost during calcination of the calamine is not either sulphur or arsenic, or any thing which can be col. lected by the sides of an horizontal chimney, as is the case in some sorts of copper and lead ores , hence it would be quite unservice- able to roast calamine in a furnace with such a chimney. The truth of this remark will appear from the following experiment. 1 took 120 grains of the best Derbyshire calamine, and dissolved them in a diluted vitriolic acid : the solution was made in a Flo. rence Flask, and the weight of the acid and flask was taken before the solution commenced. About twenty hours after the solution had been finished, I weighed the flask and its contents, and found that there had been a loss of forty grains, or one third the weight of the calamine ; about a grain of earth remained at the bottom undissolved. If the same quantity of the purest limestone had been dissolved in the same way, there would have been a loss of weight equal to fifty-four grains : the substance which is separated from calamine by calcination, or by solution in an acid, is of the same nature with that which is separable from limestone by the same processes — fixed air. This air having the property of chang- ing the blue colour of vegetables to red, as well as many other properties of an acid, and being contained in great abundance in the atmosphere, has been called by some, aerial acid; and by £50 METALLURGY. others, from its constituting nine parts in twenty of chalk and other calcareous earths, chalky acid j and from its being destruc. tive of flame and animal life, some have denominated it mephitic air. The weight which was thus lost by dissolving the Derbyshire calamine in an acid, corresponds sufficiently with that which the •workmen observe to be lost during the calcination of that mineral ; to that these processes mutually confirm each other. Bergman observes that 100 grains of Flintshire calamine lost by calcination thirty four grains* : now this quantity corresponds, as much as can be expected in things of this sort, with the loss which I observed during the solution of 120 grains of the Derbyshire calamine; for if I had dissolved only 100 grains, the loss would have been 33^. The same author, however, remarks that 100 grains of Flintshire calamine, when dissolved in an acid, gave only twenly-eight grains of air : and he thinks that six grains of water are contained in every 100 grains of that sort of calamine ; for he takes the difference which he observed between the weight of air obtained by solution, and the loss of weight sustained during the calcination of 100 grains of calamine, to be owing to the water which is dispersed during the process of caldnationt. Fontana obtained 190 grains of fixed air from 576 grains of Somersetshire calamine : according to the same proportion, had he used only 100 grains, he would have had thirty. three grains of fixed air, instead of the twenty. eight which Bergman got from the Flintshire cala. mine j I say instead of the twenty. eight, for I am inclined to think that the Derbyshire, Flintshire, and Somersetshire calamities do not differ much from each other in the quantity of air which they * Vol. II. p 327. -r Bergman has used (he same method of analysing other substances con- taining fixed air, particularly calcareous earths. He found that 100 grains of transparent calcareous spar gave, by solution in an acid, thirty-four grains of fixed air, and lost by calcination forty-five grains; tin- difference, eleven grains, he says is water; which, though expelled by the fire, remains mixed with the acid ; and hence 100 grains ofx such spar contain fifty-five grains of lime, thirty-four grains of fixed air, ai.d eleven grains of water. 1 have a little difficulty in admitting this mode of inferring the quantity of wafer con- tained in these bodies: I do not absolutely deny the justice of it; but I hesitate concerning it; because, from experiments which I made with nil the care I could, I found that fine Irinsp.irrnt spar, very white marble, &c. as nearly as could be estimated, the sauc weight, whether they were dissolved in an acid, or calcined in a strong fire. METALLURGY. 251 contain; but that the apparent difference in the analyses of them here mentioned, proceeds rather from the mode of operating than from the substances themselves. But, though future experience should prove that very pure pieces of the calamities we are speaking of do exactly agree to the quantity of air contained in them, it will not follow that the calamines, as prepared for sale by the miners or burners, will be similar to each other in all their properties; since they may be mixed with different quantities and with different sorts of heterogeneous substances, from which it may be impos. sible u holly to free them. The reader must not conclude, from what has been said, that all sorts of calamine lose one third of their weight by calcination, or afford fixed air by solution in acids. Bergman analysed some calamine from Hungary, and he found 100 grains of it to consist of eighty. four grains of the earth of zinc, three of the eartli of iron, one of clay, and twelve of siliceous earth: no mention is made of water in thi* analysis.* In the great works where calamine is prepared for the brass makers, after it has been properly calcined, by which process, as has been observed, it loses between a third and a fourth part of its weight, it is again carefully picked, the heterogeneous parts hav- ing been rendered more discernable by the action of the fire; it is then ground to a fine powder : afterwards it is washed in a gentle rill of water, in order to free it as much as possible from the earthy particles with which it may be mixed ; for these, being twice as light as the parties of the calamine, are carried off from it by the water : it is then made up for sale. A ton of the crude Derbyshire calamine, as dug from the mine, is reduced, by the various processes it undergoes before it becomes saleable, to about twelve hundred weight : and hence it has lost eight parts in twenty. Of the eight hundred weight thus lost in a ton, 6f may be esteem, ed fixed air: the remaining part, amounting to !-j. consists of some impurities which have been picked out or «asl. i MVJ>, and of some portion of the metallic part of the calamiir-. which is in. flamed and driven off during the calcination: for 1 cannot agree with Walleriusf, in supposing that the on s of zinc lose no part of their substance during the ordinary proofs of calcination; the blue Same which is visible in the finnace where the calamine is * Berg. Chem. Ess. vol. II, p. 325. t Meullur. METALLURGY. calcined, and the injury which the calamine sustains from \n calcined with too strong a fire, arc proofs lo the contrary. It would be possible to use calamine for the purpose of making brass with- out calcining it; for the fixed air would be dissipated by the heat applied in making the brass. But, as in using a ton of uncalcined calamino, there would be between six and seven hundred weight put into the brass pots which would he of no manner of use in the operation, it is a wiser method to get rid of so large a quantity of unserviceable matter ; especially as the carriage of six or seven hundred weight to the distance to which the prepared calamine is Bent for the making of brass, would cost more than the calcination of a ton of it amounts to. There are many sorts of blende or black jack, which differ from each other not only in their external appearance, but in their internal constitution. In general they contain zinc and sulphur, united together by the intervention of iron, or of calcareous earth; and they must be previously freed from their sulphur by calcina. tion, before they can be applied to the making of brass. Some sorts of blackjack lose one. fourth, others about one. sixth of their weight by calcination : what is thus dispersed consists principally of sulphur, with a little water; what remains consists of a large portion of zinc earth, mixed with one or more of the following substances, viz. iron, lead, copper, clay, and flint. Blackjack is found in North Wales, in Cornwall, and in Derbyshire; and probably it may be met with in many other parts of Great Britain. It has for many years been used, as well as calamine, for the making of brass at Bristol ; and 1 believe it was first used there under a patent : but so little was this application of it known in other parts of the kingdom, that in the year 1777, they begged me in Derbyshire (where they had a little belore that time began to save it) not to divulge the purpose to which it might be applied. It has not been long well understood, that either calamine or black jack contained any metallic substance. Matthiolus, Agricola, Ca. neparius, and other expert and more ancient metallurgists, esteem, ed calamine to be a mineral in which there was no metallic sub- stance*. Their mistake on this subject was very excusable; for the metallic substance contained in the calamine being of a volatile and combustible nature, it consumed or dissipated by the ordinary * Canep. de Atram. p. 12— SI. METALLURGY. 253 processes in which metals are extracted from their ores. Most ores require to be fluxed in contact with charcoal, or some other substance containing phlogiston, before they will yield their metals; and when they are thus fluxed, the metal, instead of being dispersed in vapour, is collected into a mass at the bottom of the vessel, or furnace, in which the operation is performed. Calamine, in like manner, must be united to phlogiston, before its metallic part, which is called zinc, will be properly formed ; but as soon as it is formed, it flies off in vapour, and taking fire, burns with a vivid flame. This phenomenon is easily made appa- rent, by mixing calamine in powder and charcoal dust together, and exposing the mixture to a melting heat ; for a flame will issue from it very different from what charcoal alone would yield : no mass of any metallic substance will be found at the bottom of the vessel ; but in tht place where the experiment is made, there will be seen many white flocks floating in the air: these flocks are the ashes of the metallic substance of the calamine j they are called flowers of zinc, lana philosophorum, nihil album, and by other fanciful names. The metallic vapour which rises from a mixture of cala. mine and charcoal, when exposed to a proper degree of heat, and the firing of which causes the flame which may be observed, can. not burn without air; and it was on this principle that Marggraf proceeded, when he extracted zinc from calamine by distillation in close vessels in 1746. He put eight parts of powdered calamine, and one of powdered charcoal, well mixed together, into an ear- then retort ; and having fitted a receiver, with a little water in it, to the m-rk of the retort, in such a manner as to exclude the air, he exposed the mixture to a strong heat; there rose into the neck of the retort, where it was condensed, the metallic vapour of the calamine. By this method he ascertained the quantity of zinc contained in different sorts of calamine. Parts. Parts. Calamine from near Cracow 16 gave 2{ of zinc. from England 16 3 — from Breslaw 16 4% • • from Hungary 16 from Holywell in Flintshire 16 He tried some stones from Aix.Ia-Chapelle, which had been given him for calamine, in the same way, but obtained no zinc from METALLURGY. them; and thence he concludes that they were not calamine stones: for every stone, says he, which being mixed with charcoal, and exposed in close vessels to the action of a violent fire, does not yield zinc, or which in an open fire does not with copper and charcoal produce brass, ought not to be considered as a calamine stone*. Ilourkel had long before given a similar definition of zinc, •when ho observed that it was the only substance in nature which had the quality of giving copper a yellow colourt. Pott wrote a dissertation on zinc in 1741, in which he enters into the history of the discovery of this semi-metal. Bergman has availed himself of all that Pott knew on that subject, and has added several things of his own : I cannot compress the matter into a less compass than he has done. " The semi. metal which at present is called zinc, was not known so much as i>y name to the ancient Greeks and Arabians. The name which it bears at pre. sent first occurs in Theophrastus Paracelsus J, but no one as yet has been able to discover the origin of this appellation. A. G. Agri- cola calls it contrefeyn §; Boyle, speltrum|| : by others it is deno- minated spiauter, and Indian tinH. Albertus Magnus, more pro. perly cal ed Bolsfadt, who died in 1280**, is the first who makes express mention of this semi-metal. He calls it golden marcasite, asserts that it approaches to a metallic nature, and relates that it is inflammable. However, as zinc is white, the name of golden marcasite is not very proper ; it would therefore appear probable that it derives that name from the golden colour which it commu- nicates to copper, had not Albertus expressly said, that copper united with golden marcasite becomes white ; but he has probably either misunderstood or misrepresented what he had heard related by others, it may also happen that zinc was formerly thought to contain gold. J. Matthesius+t, in 1562, mentioned a white and a red zinc ; but the yellowness and redness are only to be under- stood of the ores. llollandus, Basil Valentine, Aldrovandus, Caesius, Caesalpinus, Fallopius, and Scroeder, observe a profound silence on that head. JJ The eastern Indians have long since been in possession of the method of extracting pure zinc from the ore; « Opog. de Mar*, vol. I. p. 94. t Pyrito. French Trans, p. ?48. | In Operibus passim. ^ De Re mctallica. 8 PoDderib. Flammae. f Taeda Trifid.-x Cl\vraica •• In Libro Mincralium. •»• t Sarcptn. } Poll on Zinc. METALLURGY. 255 at least in the course of the last century this metal was brought from thence to Europe. Jungius mentions the importation of zinc from India, in 1674*; a metal of this kind, under the name of tutenag, is still brought from thence, which must be carefully dis- tinguished from the compound metal of that name. G. E. Van Lohneiss tells us, in 1617, that a lonu time before, zinc had been collected by fusion at Goslart. It has been long used to form orichalcum from the ores of zinc, by the addition of copper; but it does not yet appear at what time this art was invented. Pliny makes mention of the orichalcum, as also of three species of Co. rinthian vases, one of which is yellow, and of the nature of gold J. Erasmus Ebner, of Noremberg, in the year 1550, was the first who used the cadmia of Goslar for this purpose. In the year 1721, Henckel indeed mentioned that zinc might be obtained from lapis calaminaris by means of phlogiston, but he conceals the me. thod §. The celebrated Anton. Van Swab, in 1742, extracted it from the ores by distillation, at Wesferwick, in Dalecarlia||. It was determined to found a work for the purpose of extracting larger quantities of this semi. metal ; but afterwards, for various reasons, this project was laid aside: therefore the illustrious Marg- graf, not knowing what had been done by the Swedish minera- logists, in the year 1746 published a method of performing this operation, which he had discovered himself H. It is not known how zinc is extracted in China. A certain Englishman, who seve. ral years ago took a voyage to that country for the purpose of learning the art, returned safely home indeed, and appears to hare been sufficiently instructed in the secret, but he carefully Concealed * De Mineralibus. + Bericbt Von. Bergvercken. J Hist. Nat. XXX. C. II. $ Pyritologia — Hcnckel's words deserve to be quoted ; I take them from the French translation of the Pyritologia, p. 295. On fait, par exewple, avec la calami ne, non seulemcnt du fer, il est vrai en petite quanthc, niaii encore une ties-grande qunntitc de zinc, que Ton obtient non-seulement eu lui presentant le corps avec leqoel il peut s'incorporer, c'cst-4-dire le cuivrc qui est son ainian, mais encore ce demi-metal se raontre simplement par 1'ad- dition d'une mat ierc grasse qui metallise; il faut seniemeut, pour cviter que ce phenix ne se rrduise en cendre, emptcher qu'il ne se brule, et observer le terns et les circonstances. y Elogium magni hujus metallurgy ceram II. Acad. Stock, recifatum. 1 Mem. de I'Acad. de Berlin. $.36 METALLURGY*. it. We fiiul afterwards that a manufactory liud bneu established at Bristol, where zinc is said to be obtained by distillation per descensum. We have already seen that it had been before ob- tained in Sweden by distillation per uscensuni, which afterwards •was effected in larger quantity by Mess. Cronstedt and Rinian, two very celebrated mineralogists and metallurgists. The diih'cul- ties occasioned by the volatile and combustible nature of this metal, fur a long time retarded the knowledge of the ores containing it: nor is that wonderful; as, being of a metallic form, it has even to our times been considered as composed of two or three ingre. dients. Albertus Magnus thinks iron an ingredient ; Paracelsus called it a spurious son of copper ; Lemery holds it to be a species of bismuth ; Glauber, and many alchemists, consider it merely as an immature solar sulphur; Homberg, as a mixture of tin and iron; Kunckel as a coagulated mercury; Schluter, as tin made brittle by sulphur, &c. The celebrated Brandt, in 1?35, shewed that blende contained zinc*; and soon after D. Swab actually ex- tracted it from the Bologtiian pseudo-galena, which possesses a me- tallic splendor. The Baron Punch, in 1714, determined the presence of zinc in pseudo-galena from the flame and the flowerst; and in 1/40', Mr. Marggraf set the matter out of doubt. Bergman in his history of the discovery of the method of ex. tracting zinc from calamine, wholly omits the mention of Dr. Isaac Lawson ; of whom Pott, in his Essay on zinc, speks very respect, fully, acquainting us that he really obtained some grains of that semi.inetal from calamine. So that though Henckel was the first, Lawson was, probably, the second person in Europe who pro. cured zinc from calamine; whether he was the Englishman who, according to Bergman, went to China to discover the method of doing it, is what I have not been able to learn with certainty. Our English writers, who have touched on this subject, speak in high terms of Lawson, I suppose from their personal knowledge of him, for they do not refer to any written account £. Thus * Act. Upsal. + Act. Stock. f Pott gives us several quotations from a dissertation of Dr. Lavrson's D« Nihil, which I have never met with, and amongst others the following one : Qnamvis lapi- caliminaris ncc suliliinationo, lice cum iiuxu ni^ro dct zinctun, taroen >imi! mills in igne color, similis tinctura cupri, el augment uiu ponderis probabili .-iinum pnrhcnt argumcfltum lapidem calami iiarem ettc mi- ncram zinci. Pott De Zinco, p. 9. METALLURGY. 257 Dr. Pryce says, " * the late Dr. I. Lawson obserring that the flowers of lapis calaminaris were the same as those of zinc, and that its effects on copper were also the same with that semi. metal, never remitted his endeavours till he found the method of sepa- rating pur<- zinc from that ore." And Dr. Campbell, in his Sur- vey of Britain, is still more particular; " + the credit, if not the value of calamine, is very much raised since an ingenious country, man of ours discovered that it was the true mine of zinc ; this countryman was Dr. I. Lawson, who died before he had made any advantage of his discovery." The authors of the Supplement to Chambers' Dictionary, published in 1753, expressly affirm, that ** { L)r. Lawson was the first person who shewed that calamine contained zinc ; we have now on foot at home a work established by the discoverer of this ore, which will probably make it very unnecessary to bring any zinc into England." To all this I shall only add one testimony more, from which it may appear that the English knew how to extract zinc from calamine, before Mr. Van Swab taught the Swedes the method of doing it; though this gen- tleman, unless I have been misinformed, instructed the late Mr. Champion of Bristol, either in the use of blackjack for the same purpose as ca'amine, or taught him some improvements in the method of obtaining zinc from its ores. The testimony occurs in a dissertation of Henckel's on Zinc, published in 1737: he is there speaking of the great hopes which some persons had entertained of the possibility of obtaining zinc from calamine ; hopes, he says, which had been realized in England, Ce qu'un Anglois arrive de. puis peu de Bristol, dit avoir vu reussir dans son pays §. The manufactory, however, of zinc was not established at Bris. tol till about the year 1743, when Mr. Champion obtained a patent for the making of zinc. About 200 tons of zinc are annually made at the place where the manufactory was first set up ; and about seven years ago, zinc began to be made at Henham, near Bristol, by James Emerson, who had been many years manager of that branch under Mr. Champion, and his successors in the business. • Mineral. Cornub. p. 46. t Polit. Surv. of Brit. Vol. II. p. 35. t Artie. Calam. & Zinc. § This observation was first published in the 4th vol. of the Acta Pbysico- Medica Acad. Nat Car. 1737 ; but I have made the quotation from the ed. of Henckel'i Woiki, published at Paris, 1760, Vol. III. p. 494. VOL, TI. S 438 METALLURGY. Near twenty years ago, I saw th.- operation of procuring zinc from ralamine performed at Mr. Champion's copper works near 13ri>fol ; it was then a great secret, and though it be now bs. t Ai, D.M-im. Vol. I. |'.': t IntroU.adPhil. Nat. Vol. 11. 7028 ; and hence if the lightness of zinc be a criterion of its pu- rity, our English zinc is preferable to the Indian, ami nearly equal to the German zinc. If the reader has never seen a piece of zinc, it will give him some idea of it to be told, that in colour it is not unlike lead ; that it is hard and sonorous, and malleable in a small degree; that it does not melt so easily as tin or lead, but more easily than silver or copper : that in a degree of heat just sufficient to melt it, it burns away into a kind of grey ashes without being inflamed ; that in a stronger heat it burns with a yellowish blue or green flame, resolr. ing itself into a white earth, which is driven offby the violence of the fire during the combustion, or remains surrounding the burning zinc like a piece of cotton wool. This combustion of zinc is as striking an experiment as any in chemistry, and it is in the power of any person to make it, by sprinkling filings of zinc on a pan of burning charcoal, or on a poker, or other piece of iron heated to a white htat ; it is this property which renders fine filings of zinc of great use in fire-works. Zinc is a very singular metal, lie substance ; it not only burns when sufficiently heated with a vivid flame, but it yields an inflammable air by solution in the acids of vitriol and of sea salt, and even in some of its ores it ma. nifests a phosphoric quality : 1 have seen a piece of black ja< k from Freiburg, which being scratched in the dark with the nail of a finger emitted a strong white light. The Chinese zinc is said to contain about half a pound of lead in an hundred, and the German zinc somewhat more*; and our English zinc is thought by some to make the copper with which it is melted harsher and less mallea- ble than when either of the o'ther sorts of zinc is used ; though this opinion I suspect is rather founded in prejudice than in truth. There is an easy meihod, when pure zinc is required, of obtaining it : nothing more is required than to melt it with sulphur and some fat substance to prevent its calcination, for the sulphur will unit* itself to the lead, the copper, or the iron contained in the zinc, and reduce them to a kind of scoria, which may be separated from the melted zinc, but it has no action on the zim: itself +. The zinc • Berj$. E«. Vol. II. p. 318, note. t I am aware that Mr. Morvrau hat found out a method of combining tine with sulphur ; but in this g'-ncral view, I purpo«cly pass over many tniofi w hied are deservedly esteemed of great importance by persooi deeply skilled in cho- •o it try. 82 I 260 METALLURGY. made by Mr. Emerson is whiter and brighter than any other either English or foreign zinc ; but I do not know that it owes these qua. litits to its being purified by sulphur. Zinc and copper, when melt< (I to^rthi r in different proportions, constitute what are called pinchbecks, &c. of different yellow colours. Marggraf melted pure zinc and pure copper together, in a great variety of propor- tions, and he found that eleven, or even twelve parts of copper being mixed with one part of zinc (by putting the zinc into the cop. per when melted) gave a most beautiful and very malleable tombac or pinchbeck*. Mr. Baunie gives the following process for mak- ing a metal, which he says is called Or dc Manltcim, and which is used for imitating gold in a variety of toys, and also on lace.— Melt an ounce and a half of copper, add to it three drams of zinc, cover instantly the mixture with charcoal dust to prevent the cal- cination of the zinc +. This covering the melted mass with char, coal is certainly serviceable in the way the author mentions ; and it is on a similar principle, that when they melt steel at Sheffield they keep the surface of it covered with charcoal ; but I think it probable also, that the charcoal contributes to exalt the golden colour of the pinchbeck. These yellow metals are seldom so mal- leable as brass, on account of the zinc which is used in making them not being in so pure a state, as that is which is combined with copper when brass is made; yet it appears from the experiments of Marggraf and Baume before mentioned, that when pure zinc and pure copper are used in proper proportions, very malleable brass may be made thereby. Mr. Emerson has a patent for mak- ing brass with zinc and copper, as I have been informed ; and his brass is said to be more malleable ; more beautiful, and of a colour more resembling gold than ordinary brass is. It is quite free from knots or hard places, arising from iron, to which other brass is sub- ject ; and this quality, as it respects the magnetic needle, renders it of great importance in making compasses. The method of mak- ing ordinary brass I will now describe. Copper in thin plates, or which is better, copper reduced (by being poured, when melted, into water) into grains of the size of large shot, is mixed with calamine and charcoal, both in powder, and exposed in a melting pot for several hours to a fire not quite itrong enough to melt the copper, but sufficient for uniting the metallic earth of the calamine to the phlogiston of the coal ; this • Mem. of Berlin, 1774. t Chy . par M, Bawoc, Vol. 11, p. 662. METALLURGY. 2fll union forms a metallic substance, which penetrates the copper contiguous to it, changing its colour from red to yellow, and aug« menting its weight in a great proportion. The greater the surface of a definitive weight of copper, the more space has the metallic vapour of the calamine to attach itself to ; and (his is the reason that the cop. per is granulated, and that it is kept from melting and running into a mass at the bottom of the vessel, till near the end of the operation, when the heat is increased for that purpose. The German brass-makers, in the time of Erckern, used to mix sixty. four pounds of small pieces of copper with forty- six pounds of calamine and charcoal, and from this mixture they generally obtained £0 pounds of brass*. Cramer recommends three parts of powdered calamine to be mixed with an equal weight of charcoal dust and two parts of copper, and says that the brass obtained by the process exceeds the weight of copper by a fourth, or even a third part of its weight t. At most of our English brass-works they use forty. five pounds of copper to sixty pounds of calamine for making ingot brass, and they seldom obtain less than sixty, or more than seventy, pounds of brass ; at Holywell they reckoned the medium product to be sixty.eight : and heure a ton of copper by this operation, becomes rather more than a ton and a half of brass. This is a larger increase of weight in the copper than is observed in any of the foreign manufactories that I have ever read of; and it may be attributed to two causes — to the superior excel, lence of our calamine, and to our using granulated copper. Pos- tlethwayte, in his Commercial Dictionary, attributes the difference in the increase of weight acquired by the brass to the different na- tures of the coppers which are used : " There is an increase of forty.eight or fifty pounds in an hundred, if copper of Hungary or Sweden be used; that of Norway yields but thirty .fight, and that of Italy but twenty," When they make brass which is to be cast into plates, from which pans and kettles are to be made, and wire is to be drawn, they use calaminf of the finest sort, and in a greater proportion than when common brass is made — generally fifty six pounds of calamine to thirty-four of copper. Old brass which has been frequently exposed to the action of fire, when mix. ed with the copper and calamine in the making of brass, renders » Flet* minor, by Sir J. Pettys. j». 286. Newman gives the tame proportion, p. 65. fCram. An Doc. Vol. II. p. 246. 83 262 METALLURGY. the brass far more ductile, and filter for the making of fine v than it wou'd be wi'hout i( ; hut tlu- German brass, particularly that mde at Nuernberg, is, when dnwn into wire, said to be preferable to any made in England for musical instruments. If this preference be real, it will cease to exist as soon as any ingenious man shall undertake to examine the subject; for our materials for making brass are as good as any in the world. The quantity of charcoal, which is used, is not the same at all works ; it is gene- rally about u fourth part of the weight of the calamine : an excess of charcoal can be attended with no othi r inconvenience than that of uselessly filling up the pots in which the brass is made; but powdered pitcoal which is used at some works in conjunction with, or in the place of charcoal, greatly injures the malleability of the brass. As to black jack, the other ore of zinc, it is not so com. rnonly used as calamine for the making of brass. The manufactur. ers have been somewhat capricious in their sentiments concerning it ; some have preferred it to calamine, and others have wholly neglected it; and the same persons at different times have made great use of it, or entirely laid it aside. There must have been some uncertainty in the produce or goodness of brass made by this mineral, to have occasioned such different opinions concerning it ; and this uncertainty may have proceeded either from the variable qualities of the mineral itself, or from the unskilfulness of the op1 rators in calcining, &<:. a mineral to which they had not been much accustomed. Several ship loads of it were sent a few years a_i> from Cornwall to Bristol, at the price of forty shillings down to a inoidore a tt>n*. Upon the whole, however, experience has not brought it into reputation at Bristol. I'"or many purpo-.es bralass is decomposed by long expo, sure to the air, the alkali attracting water and aerial acid. Mor. tar, on the contrary, hardens by long exposure to the air, because, though >he aenal acid be attracted, yet a great part of the water exi.ales*." The changes produced by the long expo-ure of bodies to ihe air, and the causes of them, deserve a more minute investi- gation than has hitherto been bestowed on them ; some advantage nii^ht, perh:) ps, be derived from the inquiry to our manufactu- rers ; for 1 have cause to think that iron, which has been exposed to the air tor three or four years, is a very different substance from the same iron when just made : and the same observation will pro. bably hold with respect to copper and brass. — But to return from this digression. The calamine of Bohemia contains iron ; most of our English calamine contains lead ; and there are some sorts which contain both iron and lead, and other metals in different proportions : these sorts can seldom be freed from the extraneous metals ; and hence, in the ordinary method of making brass, they Mill be mixed with it, being fusible in the degree of heat usually employed in making brass. Cramer mentions a very ingenious method of making brass, by which, if it should be thought neces. sary to do it, the brass may be preserved pure from these hetero. geneous mixtures. He orders the calamine and charcoal to be mix- ed with moistened clay, and rammed to the bottom of the melting pot, and the copper mixed with charcoal to be placed upon the clay ; then, the proper degree of heat being applied, the vapour of the zinc contained in the calamine will ascend tnn>u,li (he clay, and attach itself to the copper, but the iron or lead contained m the * Elements of Mio. by K. Kir wan. p. 111. MET.AI.LMIGY. calamine, not being volatile, will remain in the clay, and (he brass when the whole is nieltnl will not be mixed with them, but pure on the surface of the clay. Mr. John Champion, brother to hint who first established the manufactory of zinc at Bristol, is a very minimus metallurgist, and he has lately obtained a patent for brass by combining zinc in vapour with heated copper and the brass is said to be very fine; whether the process he uses has any correspondence with this mentioned by Cramer, or not, his brass will certainly be free from the mixture of lead, &c. But the care to purify brass from such metallic mixtures as may be accidentally contained in the calamine, is, or is not neces- sary, according to the purposes to which brass is applied. These mixtures may probably injure the malleability of the brass, but they may at the same time increase its hardness, or render it sus- ceptible of a better polish, or give it a particularity of colour, or some other quality by which it mriy be more useful in certain ma- nufactories, than if it was quite free from them, and consisted of nothing but the purest metallic part of the calamine, united to the purest copper. This may be illustrated from what is observable in other m°tals. The red iron ore from Furncss, in Lancashire, pro- duces an iron which is as tough as Spanish iron ; it makes very fine •wire; but when converted into bars, it is not esteemed so good as that which is made in the forest of Dean, and other places. There are but few sorts of iron which, though useful in other respects, are fit for being converted into steel: some sorts of iron will ad- mit a high polish, as may be seen in many expensive grates which are sold as grates of polished steel, though they are nothing but iron; whilst others take but a very indilli r< nf polish; the Swe- dish, Russian, and Knglish irons, and even the irons made at dif- ferent furnaces in the same country, are respectively fit for some purposes, and unfit for other : he who should attempt to use the same iron for the making of wire, and for coach and waggon wheel*, would betray great ignorance in his business. In like manner, a notable dill'erence may be observed in ditferent sorts of copper, y< t all of them have their respective uses : the Swedish copper is more malleable than the copper of Hungary ; the copper of Anglesey ilillers from the copper of Cornwall and of Stafford, shire. The br.i/.iers prefer that copper which they can work with the greatest facility ; but the malleability of copper should not b« esteemed the only criterion of its goodness; for the copper whick METALLURGY. 267 is less malleable may admit a finer polish, and may last lot' when exposed, as in breweries, in the navy, &c. to the action of the fire, than the copper which is more malleable. This has been proved by experiment. Three plates of copper, equal to each other in surface and thickness, were exposed, for the same length of time, to a violent tire, with a view of seeing which would best sustain its action ; one plate was made of copper which bad been purified by a chemical process, another was made of copper from Hungary, and the third of Swedish copper. The purified copper, when freed. from the calcinated scales, had lost five grains of its weight, that of Hungary had lost eight, and that of Sweden ele- ven grains*. Queen Elizabeth, in 1565, granted by patent all the calamine in England and within the English pale of Ireland to her as?ay mas. ter William Humphrey, and one ( hristopher Schutz, a German, and, as the patent sets forth, a workman of great cunning, knowledge, and experience, as well in the finding of calamine, as in the proper use of it for the composition of the mixt metal called latten or brass +. With these patentees were soon after associ- ated some of the greatest men in the kingdom, as Sir Nicholas Bacon, the Duke of Norfolk, the Earls of Pembroke and Leices- ter, Lord Cobham, Sir William Cecil, and others, and the whole were incorporated into a society, called, The Society for the Mi- neral and Uattery Works, in the year 1568. Mines of latten, whatever may have been at that period meant by the word, are mentioned in the time of Henry VI. who made his chaplain, John Bottwright, comptroller of all his mines of gold and silver, cop. per, latten, lead, within the counties of Devon and Cornwall J; yet I am disposed to think, that the beginning of the brass manu- factory in England may be properly referred to the policy of Eli- sabeth, who invited into the kingdom various persons from Ger- many, who were well skilled in metallurgy and mining. In 1639, a proclamation was issued prohibiting the importation of brass wire§; and about the year 1650, one Demetrius, a German, set * Mem.de Brux. Vol. IV. f Opera Mineralia Explicate, p. 34. This work was written by Moses Stringer, M.I), in 1713, and contains a complete history of tbt* ancient corpo- ration of the city of London, of and for the mines, the mineral and battery works. J Id. p. 90. 4 Id. p. 147. METALLUR' tip a brass work in Surry, at the expence of six thousand pounds * ; and above eight thousand men are said to have been employed in the brass manufactories which were established in Nottinghamshire, and near London ; yet Sir John Pettus in his account of royal mines, published in 1670, observes that these brass works were then decayed, and the art of making brass almost gone with tho artists +. But though the art was then almost gone, yet it was ne- Ter, after its first establishment, altogether lost ; for about the year 1708, we find that there were brass manufacturers in England, and that they presented a memorial to the House of Commons, setting forth several reasons for continuing the brass manufactory in this kingdom, and soliciting for it the protection of parliament |. In this memorial they stated, that England, by reason of the inexhaus. tible plenty of calamine, might become the staple of brass manufacto- ry for itself and foreign parts ; that the continuing the brass works in England would occasion plenty of rough copper to be brought in, and make it the staple (in time) of copper and brass; that the Swedes had endeavoured to subvert the English brass manufactory, by lowering the price of Swedish brass wire, inveigling away workmen, and other means. In compliance with the purport of this memorial, an act of parliament was passed in the same year, by which the former duties payable on the exportation of copper of the produce of Great Britain, and of brass wire, were taken off, and these articles were allowed to be exported free of duty. In 1720 it was remarked, that this nation could supply itself with copper and brass of its own produce, sufficient for all occasions, if such duties were laid on foreign copper and brass, as would dis. courage their importation, and 'at the same time encourage the sale of our own metals§. At present the brass manufactory is estab. lishtd among us in a very great extent ; we are so far from being obliged to have recourse to any of our neighbours for this commo- dity, that we annually export large quantities of manufactured brass to Flanders (it was formerly called Flanders metal), France, Germany, Portugal, Spain, Russia, Africa, and most other parts of the world. In 1783, a bill was passed by the House of Com- mons for repealing certain statutes prohibiiing the exportation of • Essays on Mtl:il. Words— Brass. f Fodimc Regal, p. S3. $ Oper. Min. Exp. 156. \ State of the copper and Brass Manufactures, by W. Wood — the same per- ton whom Swift handled so roughly in his Drapicr's Letter*. METALLURGY. 269 brass. In the reign of Edward III. the exportation of iron, either made at home or brought into Kngland, had been prohibited upon the pain of forfeiting double the value of the quantity exported*. And in the reigns of Henry VIII. and Edward VI. several acts of parliament had been passed, prohibiting the exportation of brass, copper, latten, bell. metal, pan-metal, gun. metal, shrof.metal, un. der the 'same penalty t. The general reason for passing these acts certainly does not apply to the present state of our mines and ma- nufactures, for the reason was this — lest there should not be metal enough left in the kingdom fit for making of guns and other en. gines of war, nor for household utensils. The fort-mentioned acts of parliament were particularly repealed, by an act passed in the sixth year of William and Mary, by which it was rendered lawful to export, after the 25th of March, 1694, all manner of iron, cop- per, or mundick metal ; but the prohibition of the other metals was continued. The brass-makers in 1783 applied for the same liberty which had been granted to the iron and copper smelters, a liberty of exporting the crude commodity ; this liberty was not granted them by the legislature, for the bill which had passed the House of Commons, was thrown out by the Lords. The Birming- ham manufacturers presented a petition to the House of Com. mons, against the bill which was then pending; in which petition it was represented — that frequent attempts had been made to erect manufactures similar to those of Birmingham in different parts of Europe, and that thi- excellence of some of the Birmingham arti- cles depended upon brass of very different qualities ; and that, for. tnnately for this country, there were several sorts of brass that were peculiarly adapted to the different branches of their manufac- tures ; so that the sort which was suitable for one article, was im- proper for another : and that they had reason to believe, that the manner of adapting the various sorts of English brass to different articles in their manufactures, was not known to foreigners ; but that if free liberty was given to export brass, every maker might be induced to discover the peculiar uses of his sort, and that very disagreeable consequences to their manufactures might thereby be produced* The petitioners also represented — that brass-makers, in different provinces of this kingdom, had not succeeded in making • 28 Ed. III. c. 5. t SI Hen. VIII. c. 10,— S3 Hen. VIII.c.1,— 8&3 Ed. VI. c.37. 270 METALLURGY. (he sorts of brass m:ul«i in other pro vinros; and that one great'companjr of 1>! is had not succeeded in making IMMVS MI i;ih|. lor the Birmingham market, tbot§h they bad profeesed in • nne-t desire to do so. And they humbly apprehended, that tli r had I such a quantity of brass exported as to midf-i it a national object ; and that there, was not a probibility of any such quantity beini; exported, though so much mi^ht be as to raise a ruinous competition to their manufactures, &c. The brass makers, it may be said, suffered an injury in being pro. hibited from exporting a commodity by which they might be gainers, merely lest the great brass manufacturers should lose somewhat of their profit, by having a less extensive trade. But this is not a pro- per state of the case ; it is not for (he sake of the gn at brass ma- nufacturers that the prohibition of exporting brass is continued, nor is there any want of that metal in the kingdom ; but lest foreigners should rival us in a trade which, in affording employment to many thousands of people, is of the greatest consequence to (he kingdom in general. The proprietors of fullers earth have been prohibited from exporting that material ; not out of any partial regard of the legislature for the great woollen manufacturers, but lest the number of persons employed in that manufacture should be much lessened, if foreigners were supplied with an article so essentially necessary to its perfection, as fullers earth is found to be ; and though other nations have fullers earth, yet that which is met with in England is reckoned to be fitter for the woollen manufactory, than any other which has yet been found in any part of the world. This observa- tion may be applied to the subject we are speaking of. Great quantities of good brass are made by most nations in Europe, as well as by the English ; but the English brass is more adapted to the Birmingham manufactories than any other sort is ; and hence in France, Portugal, Russia, and Germany, our unmanufactured brass is allowed to be imported free of duty, but heavy duties are imposed in those countries on manufactured brass when imported. The manner of mixing different sorts of brass, so as to make the mixture fit for particular manufactures, is not known to foreigners ; though this is a circumstance of the gn-atest importance : hut there can be little doubt, that if foreign nations were possessed of all (be torts of English brass, they would soon seduce our workmen to instruct them in the manner of mixing them, and in some other little circumstances, which are not generally known, but on which METALLVRGY. £71 (he sucress of the manufacture depends in a great degree. On these and other accounts, till commerce puts on a more liberal appear- ance than it has hitherto done in Kurope ; till different nations shall be disposed to consider themselves, with respect to commercial interests, as different provinces only of the same kingdom ; it may, probably, be thought expedient to continue the acts prohibiting the exportation of unwrought brass, though the reasons which induced the legislature to pass them have long since ceased to exist. I do not enter into the inquiry, when the custom-house officers began to make a distinction between wrought and unwrought brass, so as to admit the former to an entry for exportation and not the latter; but I apprehend it was in the year 1721, when various goods and merchandizes of the product or manufactures of Great Britain were allowed, by act of parliament, to be exported free of duty ; lapis calaminaris, lead, and several other articles are enumerated in the act, on which the duty was to be continued ; but in this enumera- tion there is no mention made of unwrought brass, though it may properly be considered as a merchandize of the product of Great Britain ; . but the quantity of brass which was then made in the kingdom was so small, that it did not, probably, enter into the con. temptation of the legislature to forbid an exportation, which did not seem likely ever to take place. Brass is made in various parts of Great Britain ; but the Bristol, Macclesfield, and Warrington companies are the only ones, I believe, which go through all the processes of smelting the copper from its ore, of preparing the cala- mine, and of uniting it with copper for the making of brass. The trade of brass making has within these few months been much de. ranged throughout the nation, by an agreement which has been entered into by some of the principal copper companies, to the exclusion of others, to buy up all the copper of the mines now at work in the kingdom. The effect of this plan is not yet generally either felt or foreseen. [Bishop Watson. [ 272 ] CHAP. II. ON ORICHALCUM, AU RICH A LCUM, OB THE BUASS OF THE ANCIENTS. W K have a proof, from the writings of Cicero, that the Romans, in his time, uml rstoocl by the term orichalcum, a metallic substance resembling gold in colour, but very inferior to it in value. lie puts the following case — 'k Whether, if a person should offer a piece of gold to sale, thinking that he was only disposing of a piece of orichalcum, an honest man ought to inform him that it was really gold, or might fairly buy for a penny what was worth a thousand times as much*." It is not contended, that the argument, in this place, required any great accuracy in ascertaining the relative va. lues of gold and orichalcum ; yet we may reasonably conclude from it, that orichalcum mi^ht by an ignorant person be mistak' H for gold, and that it was but of s.nall estimation when compared with it. Julius Caesar robbed the capitol of three thousand pound weight of gold, and substituted as much gilded copper in its stead -f ; in this species of sacrilege, he was followed by Vitellius, who despoiled the temples of their gifts and ornaments, replacing the gold and silver by tin and orichalcum J. From this circumstance also, we may collect, that the Roman orichalcum resembled gold in colour, though it was far inferior to it in value. It is probable, that the orichalcum, here spoken of, was a metal, lie substance greatly analogous to our brass, if not wholly the same with it. The value of our brass is much less than that of gold, and the resemblance of brass to gold in colour, is obvious at first sight. Both brass and gold, indeed, are susceptible of a variety of shades of yellow ; and, if very pale brass be compared with gold mixed with much copper, such as the foreign goldsmiths, especially, use in their toys, a disparity may be seen ; but the nearness of the resem- • Circer. dp Off. L. III. t Suet, in Jul. Caes. C. HV. $ Id. in Vital. C. VI. ON ORICHALCUM. 273 blance is sufficiently ascertained in general, from observing that substances gilded with brass, or, as it is commonly called, Dutch leaf, are not easily distinguished from such as are gilded with gold leaf. The Romans wore not only in possession of a metallic substance, called by them orichalcum, and resembling gold in colour, but they knew also the manner of making it ; and the materials from which they made it, were the very same from which we make brass. I am sensible, that in advancing this opinion, I dissent from authors of great credit, who esteem the art of making brass to be wholly a modern invention. Thus M. Cronstedt (though I differ in opinion from him) u does not think it just to conclude, from old coiiw and other antiquities, that it is evidently proved, that the making of brass was known in the most ancient times* ;" the authors of the French Encyclopedic assure us, that ** our brass is a very recent invention t :'' and L)r. Laughtou t says, " the vessels here called brazen, after ancit-nt authors, cannot have been of the materials our present brass is composed of; the art of making it is a modem discovery." Pliny, "peaking of some copper which had been discovered near Corduba in (he province of Andalusia in Spain, says, u this of all the kinds of copper, the Livian except, d, absorbs most cadmia, and imitates the goodness of aurichalcum §." The expression, * absorbs most cadmia,' seems to indicate, that the copper was increased in bulk, or in weight, or in both, by means of the cadmia. Now it is well known, that any definite quantity of copper is greatly increased, both in bulk and in weight, when it is made into brass by being fluxed in conjunction with calamine. The other attribute of the copper, when mixed with cadmia, was, its resembling aurichalcum. We have seen from Cicero, that the term orichalcum was applied to a substance far less valuable than gold, but similar to it in colour ; and it is likely enough, that the Romans, com. monly called the mixture of copper and cadmia, orichalcum, though Pliny says, that it only resembled it ; he, as a naturalist, speaking with precision, and distinguishing the real orichalcum, which in his time, he says, was no where produced, from the factitious one, which from its resemblance to it, had usurped its name. » Miner, p. 218. t Art. Orichalquc. I Laughton's Hiit. of Ancient Egypt, p. 58. ^ Hilt. Nat. L. XXXI V. 3. II TOL. VI. T 3?4 ON ORICHALCUM; Sex(us Pompcius Fostus abridged a work of Verrius Flaccos, jf grammarian of considerable note in the time of Augustus. In this abridgment, he defines cadtnia to be an earth which is thrown upon copper, in order to change it into orichalcum*. The age in which Festus flourished is not ascertained : he was unquestion. ably posterior to Martial, and some have thought that he lived un- der the Christian Emperors. But leaving that point to be settled by the critics, if he expressed himself in the words of the author whose work he abridged, we have from him a decisive proof, that cadmia was considered as a species of earth, and that the Romans used it for the converting of copper into a metallic substance called, in the Augustan age, orichalcum. In opposition to this, it ought to be remarked, that some under, stand by the cadmia of Pliny, not calamine, but native arsenic. They seem to have been led into this opinion, from observing that Pliny says, lapis aerosus was called cadmia. For apprehending that by lapis aerosus Pliny understood a kind of stone which caused ulcer* and erosions in the flesh of those who were occupied in working it, and knowing that arsenic produced such an effect, they have concluded that cadmia was native arsenict. This, probably, is a mistake arising from a misinterpretation of the word aerosus. Pliny usually, if not constantly, applies that word to substances in which copper is contained, without having any respect to the actions of such substances on the flesh of animals. Arsenic, moreover, when mixed with copper, does not give a gold, but a silver. like appear, ance to copper. And lastly, Pliny + , in another place expressly says, that the stone from which brass (aes) was made, was called cadmia; now it is impossible to make either brass or copper from arsenic. Ambrose, bishop of Milan, in the fourth century, says, that copper, mixed with certain drugs, was kept fluxed in the furnace till it acquired the colour of gold, and that it was then called auri. chalcum§. Primasus, bishop of Adrumetum in Africa, in the * Cadmia Trrra qme in cs conjicitur, ut fiat orichalcum. — Fes. dc Vcr. Seq. + nous snpconnons que Pline a voulu designer par lapis xrosus, une piorre qut mange et fait dcs ulceres ou erosions a ceur qui la ir.ivaillent, et qui r*t probablcment 1'arsenic vierge. Miner, par M. Valmont de Oomare, V. II. p. 04.— If the wor^had been rro.u,, .th.ij criticism might have beeii admitted. J Hist. Nat. L. XXXIV. 10. j jEJnarhque in rornafce,qufbusdam mrdicaminibusadmixt!*, tamdiu conflatur u-que duracoloremauri accipiat, et dichur aurichalcum.— Arab, in Apoc. C.I- ON OAlCHALCUKf. 275 Sixth century, observes, that aurichakum was made from copper^ brought to a golden colour by a long continued heat, and (he ad- mixture of a drug*. Isidorus, bishop of Seville in Spain, in the seventh century, describes aurichalcum as possessing the splendor of gold, and the hardness of copper, and he uses the very words of Primasius respecting the manner of it's being madef. The drug spoken of by these three bishops was probably Cadmia. Prepared cadmla is highly commended by Pliny as useful in disorders of the eyes| ; And it is still with us, under the more common appellation of calamine, in some repute for the same purpose. Hence, consu dering the testimonies of Festus and Pliny to the application of cadmia in making either orichalcum, or a substance imitating the goodness of orichalcum, we cannot have much doubt in supposing, that cadmia was the drug alluded to by Ambrose, and by those who seemed to have borrowed, with some inaccuracy of expression, his description of the manner of making orichalcum. What we call brass, was anciently in the French language called archal; and brass wire is still not unfrequently denominated fit d'archal. Now if we can infer, from the analogy of languages, that archal is a corruption of aurichalcum, we may reasonably conjecture, that our brass, which is the same with the French ar- chal, is the same also with the Roman aurichalcum. Though we may, from what has been advanced, conclude, with, out much apprehension of error, that the Romans knew the me. thod of making brass, by melting together calamine and copper; yet the invention was probably derived to them from some other country. We meet with two passages, one In Aristotle, the other in Strabo, from which we may collect, that brass was made in Asia, much after the same manner in which it appears to have been made at Rome. Strabo informs us, that in the environs of Andera, a city of Phrygia, a wonderful kind of stone was met with, which bting calcine d became iron ; and being then fluxed with a certain earth, * Aurichalcum ex ere fit, cum igne multo ; et medicamine adhibito, perdu- •itur ad •nreom colorem. — Prima. in Apoc. C. I. •f Aurichalcum dictum, quod et splendorem auri, et duritiara eris pouideat ; fit autemex sere et igne multo, ac medicaminibus perducitur ad aureutn «olo- rem. — Isid. Orig. + Hist. Nat. L. XXXIV. C, X. T * ON ORICHALCUM. dropped out a silver-looking metal, which, being mixed with cop. per, formed a composition which some called orichalcum*. It is not improbable, I think, that this stone resembled black jack, or some other ore of zinc. Black jack may, in a common way of speaking, be called a stone. It abounds in iron ; and, when cal. cined, looks like an iron earth ; it yields ziuc by distillation, some- times mixed with silver and lead : and both the metallic substance which may be extracted from blackjack, and the sublimate which arises from it whilst it is smelted, will, when mixed with copper, make brass. The Mossynaeci inhabited a country not far from the Euxine Sea ; and their copper, according to Aristotle, was said to have become splendid and white, not from the addition of tin, but from it's being mixed and cemented with an earth found in that country. t This cementing of copper with an earth, is what is done, when brass is made, by uniting copper with calamine, which is often called, and indeed has the external appearance of, an earth ; and that Asia was celebrated for its cadmia or calamine, we have the testimony of Pliny J. The copper of the Mossynaeci is said to hare become white by this operation. Whiteness appertains to brass, either absolutely or relatively ; for brass is not only much whiter than copper, but when it is made with a certain quantity of a par. ticular sort of calamine, for there are very various sorts of it, its ordinary yellow colour is changed into a white. Cicero, we have seen, supposes that orichalcum might have been mistaken for gold, and as such it must have been yellow ; yet Virgil applies the epi. thet white to orichalcum : Ipse debinc auro squalentem alboquc orichalco Circumdat loricam humeris §. Aristotle also speaks of having heard of an Indian copper, which was shining, and pure, and free from rust, and not distinguishable in colour from gold|| ; and he informs us, that amongst the vessels of Darius there were some, of which, but for the peculiarity of their smell, it would have been impossible to say whether they were made of gold or copper. This account seems very descrip- tive of common brass, which may be made to resemble gold per- * Slntl). On. L. XI 11. f Aris. de Mirab. Op. Tom. II. p. 781. f Hist. Nat. L. XXXI V. C. II. \ Virg. Ma. L, XII. 87. | Ari3.de Mi rab. T. II. y. 719. ON ORICHALCUM. 977 fectly in colour; but which, upon being handled, always emits a strong and peculiar smell, not observable either in gold or gilded copper. The kings of Persia, who preceded the Darius mentioned by Aristotle, were in possession of similar vessels ; but they seem to have been rare, and of course were held in high estimation. Among the magnificent presents of gold and silver vessels which Artaxerxes •nd his counsellors gave to Ezra, for the service of the temple at Jerusalem, there were twenty basons of gold, and but two vessels of yellow shining copper, precious as gold, or, as some render the words, resembling gold*. Sir John Chardin, in his MS. note, has mentioned a mixed metal used in the East, and highly esteemed there; and, as the origin of this composition is unknown, it might, for aught we know, be as old as the time of Ezra, and be brought from those more remote countries into Persia, where these two ba. sons were given to be conveyed to Jerusalem. *' I have heard," says the note, " some Dutch gentlemen speak of a metal in the island of Sumatra, and among the Macassars, much more esteemed than gold, which royal personages alone might wear. It is a mix- ture, if I remember right, of gold and steel, or of copper and steel." He afterwards added to this note (for the colour of the ink differs), " Calmbuc is this metal composed of gold and copper. It in co- lour nearly resembles the pale carnation rose, has a very fine grain, the polish extremely lively. I have seen something of it, &c. Gold is not of so lively and brilliant a colour ; I believe there is steel mixed with the gold and copper." He seems to be in doubt about the composition, but very positive as to its beauty and high esti. mationt. The supposition of brass having been anciently made in India, seems to be rendered improbable by both Pliny and Strabo; Pliny expressly saying, that the Indians had no copper! , and without copper we are certain that brass cannot be made ; and Strabo re. presenting them as so ignorant of the art of fluxing metals§, that according to him, if they had been possessed of the materials, they would not have had the ability to use them for the composing of brass. But these writers, it is apprehended, knew very little of India. Strabo, in particular, laments his want of materials to compose a consistent account of India; and few of the authors • Ezraviii.27. f Banner's Obs. on Scrip. Vol. II. p. 491. J Hist. Nat. L. XXXIV. t. XVII. $ Gto. L. XIV T 3 273 ON ORICHALCITM. from whose works Pliny compiled his Natural History, can be supposed to have 1) ir out fhe mixture melted into the mould of the first balls, ami there will not come forth four, nor scarce three balls, the weight of the four ball" lv ing res«rvd." This subject has been prosecuted since Glau'ter s tiinet, and it has been c'i-co- vered, that when metallic substances are melted to.Hh r, it seldom happens that a cul'ic inch of each of the two ingredients will form, a mass exactly equal to two cubic inches ; the mixture will in some instances be greater, and in other less than two cubic inches. In the instance of t'n and copper, where the bulk of the mixture is so much less than the sum of the bulks of the two component parts, it might be expected that the compound metal would possess pro. pcrties, not mere'y intermediate between those of copper and tin, but essentially different from them both. And accordingly we find, that this mixture is not only more brittle, more hard, and more sonorous, than either copper or tin; but it is more dense also, than either of them ; a cubic foot of it weighing, not only more than a cubic foot of tin, but than a cubic foot of copper itself. Pot-metal is made ot copper and lead, the lead being one.fourth or one-fifth the weight of the copper. In Pliny's time pot. metal (ollaria temperatura) was made of a pound and a half or two pounds of lead, and an equal portion of tin, mixed with 100 parts of copper. Copper and lead seem not to be combined together in the same way that copper and tin are ; for when pot. metal is exposed to a melting Ktat, the lead is first fused, and shews itsetf * Waller. Min.r. vol. II. p. 842. New Chem. by Lewis, p. 66. Macq. Cbcm. vol. I. p. 70. En<. Tran-.. + Glaober's \Vork-, fol. ed. 1689, p. 81. f Gelh-rt'i Cliy. Metal. & Chem. Diet. art. Allay. VOL. TI. U 190 ON METAL9. in little drops over the surface of the pot-metal, whilst the copper Temains unfused. It is reported of James II. that he melted down and coined alt the brass truns in Ireland, and afterwards proceeded to coin the pewter with this inscription — Melioris tessera fati. The Con- gress in America had recourse to the same expedient : they coined several pieces of about an inch and a half in diameter, and of 240 grains in weight; on one side of which was inscribed in a circular ring near the edge— Continental Currency, 177G — and within the ring a rising sun, with — fiigio — at the side of it, shining upon a dial, under which was — Mind your business. — On the reverse were thirteen small circles joined together like the rings of a chain, on each of which was inscribed the name of some one of the tliir. teen states ; on another circular ring, within these, was inscribed— American Congress — and in the central space— We are One. — 1 have been particular in the mention of this piece of money, be. cause, like the leaden money which was struck at Vienna, when that city was besieged by the Turks in 1529» it will soon become a great curiosity. I estimated the weight of a cubic foot of this continental currency; it was equal to 7440 ounces: this exceeds the weight of a cubic foot of our best sort of pewter, and falls short of that of our worst; I conjecture that the metal of the conti. nental currency consisted of twelve parts of tin and of one of lead. Plautus*, and other Roman authors, make mention of leaden mo. ney ; some are of opinion that we ought to understand by that expression, copper mixed with lead ; but that cannot be the mean, ing, if it be true, that the Romans did not mix lead with their copper currency till the age of SeptimiusSeverus, for Plautus lived many years before that emperor. I will not enter into the con. trovorsy : and I have introduced this observation relative to the leaden money of the Romans, merely to shew the correspondence which some of the Roman copper medals bore to oar pot-metal ; for those which were struck after the age of Septimiui Severus, being exposed to a proper degree of heat, sweat out drops ot lead, 45 it has been remarked our pot. metal does ; but metals of greater antiquity have no such property t. » T.irc sis, fahor, qiii nidrro solrs plmnbrus nnmmo*. Plan. Mos. A. IV. I,. XI. el Canin. A. II. S. III. L. XL. ,t Mart. L. X. K. LXXIV. t Illi mini qui Mutlii hnjiis ntnore trnrnmr, rum montMuin aeream ante Srp- rimluiu Srvcrutn cusam ignc prohcnt nihil plutnbi indc srccrni deprehendunt ON METALS. The sex have in all ages used some contrivance or other to en. able them to set off their dress (o the best advantage ; and the men were probably never without their attention to that point. We find Juvenal* satirizing the emperor Otho for making a speculum part of his camp equipage. Res memoranda novis annalibus, atque recenti Historia, speculum civilis sarcina belli. Homer, in describing Juno at her toilet +, makes no mention of a speculum ; but in Callimachus + we see, though it suited not the majesty of Juno, nor the wisdom of Pallas, to use a speculum before they exhibited their persons to Paris, who was to determine the prize of beauty; that Venus, on the same occasion, had fre- quent recourse to one, before she could adjust her locks to her own satisfaction. The most ancient account we have of the use of specula is that in Exodus (xxxviii. 8.) " And he made the laver of brass [copper, or a mixture of copper and tin] and the foot of it of brass of the looking-glasses of the women." The English reader may wonder how a vessel of brass could be made out of looking-glasses ; the Hebrew word might properly be rendered by specula, or metallic mirrors. The Jewish women were, probably, presented with these mirrors, as they were with other articles of value by their Egyptian neighbours, when they left the country; for it was the custom of the Egyptians, when they went to their temples, to carry a mirror in their left hand§: it is remarkable, that the Peruvians, who had so many customs in common with the Egyptians, were very fond also of mirrors ; which they ordinarily formed of a sort of lava that bore a fine polish. Pliny || says, that the best specula were anciently made at Brun. dusium of copper and tin ; that Praxiteles, in the time of Pompej the Great, was the first who made one of silver ; but that silver ones were in his time become so common, that they were used even by the maid servants. The metallic mixture of tin and cop. AHter autem comparau sunt numismata post aetatem Severi cusa, quippe ex «juibos guttule qusedam plumbi, vcl modico ignis calore diversis in locis expri- muntur. — Savot de Num. Ant. P. II. C. I. These pot-metal medaU were pro- bably cast. • Sat. II. 1. 108. f II. L. XIV. 1. 170. f Hym. in Lavac. Pallart. S Cy"1' de Ado- 1 Hiit. Nat. L. XXXIII. S. XLV. ON METALS. per was known long before the age of Pliny; it is mentioned by Aristotle*, incidentally, when he is describing a method of rendering copper white, but not by tin ; and from its great utility, it will probably never fall into disuse. We have ceased, indeed, since the introduction of glass mirrors, to use it in the way the ancients did; but it is still of great use amongst us, since the specula of reflecting telescopes are commonly made of it. Mr. Mudge has ascertained +, not only the best proportion in which the copper and tin should be mixed together, but has found out also a method of casting the specula without pores. He observes, that the per. fection of the metal, of which the speculum should be made, consists in its hardness, whiteness, and compactness. When the quantity of tin is a third of the whole composition, the metal then has its utmost whiteness ; but it is at the same time rendered so hard that it cannot be polished without having its surface splin- tered and broke up. After many experiments, he at length found that fourteen ounces and one half of grain tin];, and two pounds of copper made the best composition ; an addition of half an ounce more tin rendered the composition too hard to be properly polish, ed. The casting the metal so as that it may be compact and with, out pores, is a matter of the greatest consequence; he hit upon the manner of doing it by accident. His usual way of casting a speculum metal, was to melt the copper and to add the tin to the melted copper : the mass when cast was seldom free from pores. After having used all his copper in trying experiments to remedy this defect, he recollected that he had some metal which had been reserved, when one of the bells of St. Andrew had been re-cast : he added a little fresh tin to it, and casting a metal with it, it turned out free from pores, and in all respects as fine a metal as he ever saw. Upon considering this circumstance, he proceeded to form a metallic mass in the usual way, by adding tin to melted copper; this mass was porous, it was in the state of the bell. metal he had tried ; and upon re-melting it, it became, as the bell-metal * DC iMirab. f Philos. Trans. 1777. p. 296. | Grain tin is worth ten or twelve shillings per hundred more than mine tin, because it is smelted from a pure mineral by a charcoal fire ; whereas mine tin if usually corrupted with some portion of mundick, and other minerals, and is always smelted with a bituminous fire, which communicates a harsh, sulphu- reous, injuriousquality to the metal. Pryce, Min. Corou. p. 137. — Mr. Mudge probably used u hat is called grain-tin iu UlC shops, or the purest sort, which is usually sold in piece* like icicles. ON METALS. 293 had done, compact and free from pores. He accounts for this dif- ference by observing, that the heat necessary to melt copper, cal- cines part of the tin ; and the earthy calcined particles of the tin, being mixed in thf mass of the metal, render it porous; but the composition of tin and copper, nutting with less than half the heat requisite to melt the copper, the tin is not liable to be calcined in the serond melting, as in the first. I am rather disposed to think, that the absence of the pores is to be attributed to the more perfect fuMon of the metal : for I have observed at Sheffield, that the same wi-ight of melted steel will fill the same mould to a greater or less height, according to the degree of fusion the steel has been in ; if it ha> been in a strong heat, and thin fusion, the bar of cast steel will be an inch in thirty. six shorter than when the fusion has been less perfect. Upon breaking one of the bars, which had been made from steel in an imperfect fusion, its inside was full of blebs ; a shorter bar of the same weight and diameter, which had been in a thin fusion, was of a closer texture. Now the mixture of tin a.i ! cupper melts far easier than copper does, and it is likely, on tiiAt account, to be in a thinner fusion when it is cast. It may deserve to be remarked, and I shall have no other oppor. tunity of doing it, that the melting or casting of steel was intro- duced at Sheffield, about forty years ago, by one Waller from London ; and was afterwards much practised by one Huntsman, from whom steel so prepared, acquired the name of Huntsman's cast steel. It was first sold for fourteen-pence, but may now be had for ten. pence a pound ; it costs three. pence a pound in being melted, and for drawing ingots of cast steel into bars of the size of razors, they pay only six shillings for a hundred weight, and ten shillings for the same quantity when they make the bars into a size fit for small tiles, &c. The cast steel will not bear more than a red heat ; in a welding heat it runs away under the hammer like sand. Before the art of casting steel was introduced at Sheffield, all the cast steel used in the kingdom was brought from Germany ; the business is carried on at Slufikld with greater advantage than at most other places, for their manufactures furnish them with great abundance of broken tools ; and these bits of old steel they pur* chase at a penny a pound, and melt them, and on that account they can atiord their cast j>t<-el cheaper than where it is made altogether from fresh bars of steel. [ 294 ] CHAP. IV. OF TINNING COPPER — TIN — PEWTER. UNHAPPILY for mankind, the fatal accidents attending the use of copper vessels, in the preparation of food and physic, are too common, and too well attested, to require a particular enumeration or proof: scarce a year passes, but we hear of some of them, espe. cially in foreign countries; and many slighter maladies, originating from the same source, daily escape observation, or are referred to othor causes, in our own. In consequence of some representations from the College of Health, the use of copper vessels in the fleets anil armies of Swe- den was aboli-hed in the year 1754; and tinned iron was ordered to be substituted in their stead*. The Swedish government de. serves the greater commendation for this proceeding, as they have great plenty of excellent copper in the mines of that country, but no tin. An intelligent surgeon suggested, in 1757, the probability of the use of copper vessels in the navy, being one of the causes of the sea scurvy, and recommended the having them changed for ves. sels of iron ; he remarked, that of the 200 sail of ships which went to sea from Scarborough, most of them used iron pots for boiling their victuals, and (hat the symptoms called highly scorbutic, were never seen, except in some few of the larger ships in which copper vessels were used t. Notwithstanding this hint, and the example of Sweden, I do not know that any other European state has pro- hibited the use of copper vessels for the dressing of food on board their ships ; hut many of them have shewn a laudable attention to pr.-v ut its malignity, by inquiring into the best manner of covering its surfiire with some metallic substance, less noxious, or less liable to be dissolved than itself. This operation is usually called tinning, because tin is the principal ingredient in the metallic mixture, which is made use of for that purpose ; and, indeed, since the year 1765, * Mem. de 1'Acad. de Prussr, par M. Paul, vol. IV. Dis.PrH. p. 63. f Medical Observ. by a Society of Phyi. in Load. vol. II. p. 1. TINNING COPPER, &C. it has been frequently, in (his country at least, used alone. In that year, The ""ociety for the Encouragement of Arts, Manufac- tures and Commerce, thought it an object deserving their attention, to offer a premium for the tinning copper and brass vessels with pure tin, without lead or any other alloy. There were several candidates fur the premium; and since that time, the tinning with pure tin. and hammering it upon the copper, has become rery general in England. But this mode of tinning does not appear to have been known, or at least it docs not appear to have been adopted in other countries ; for in the Memoirs of the Royal Aca- demy at Brussels, for the year 1780, M. 1'Abbe Marci recom- mends, as a new practice, the tinning with pure block-tin from England ; though, he says, block tin is a compound body, even as it is imported from England; but he thinks it a much safer co- vering for copper than what is ordinarily used by the braziers ; and he gives -ome directions as to the manner of performing the operation. The Lieutenant General of the Police at Paris, gave it in commission to the College of Pharmacy, in 1781, to make all the experiments which might be necessary for determining — whe- ther pure tin might or might not be used for domestic purposes, without danger to health ? The researches which were made, in consequence of this commission, by Messieurs Chai land and Bayen with great ability, were published by order of the French govern, ment ; and they have greatly contributed to lessen the apprehen. sions relative to the use of tin, which had been generally excited by the experiments of Marggraf, published first in the Berlin Memoirs for 1747. That gentleman, in pursuing an experiment of Henckel, who first discovered arsenic in tin, shewed, that, though there was a sort of tin which being fluxed from an ore of a particular kind, contained no arsenic, the East India tin, which is generally esteemed the purest of all others, contained a great deal of arsenic. M. Bosc d' Antic, in his works, which were published at Paris, 1780, sets aside the authority of Marggraf, Cramer, and Hellot, relative to the existence of arsenic in tin ; and is not only of opinion, that the Cornish tin doi'S not conceal any arsenic in its substance, but that its use as kitchen furniture is not dangerous. Messieurs Churland and Bayen found that neither the E.ist India, nor the purest sort of English tin, contained any arsenic ; but that the English tin, usually met with in commerce, did contain arsenic ; though in so small a proportion that it did not amount, in that species of tin TINNING COPPER, &C. contained the mo>l of it, to more than one grain in an ounce ; that is, it did not constitute more than one five.hu;ulre*ith and seventy sixth part of the weight of the tin, tin-re being 576 giains in a J-'rtnch ounce. This proportion of arsenic is so wholly incon-iilerable, that it is very properly concluded, that the internal use of such small portions of tin, as can mix themselves with our food, from being prepared in tinned vessels, can be in no sensible degree dangerous on account of the arsenic which the tin may con- tain. But though tin may not be noxious, on account of the arsenic which it holds, it still remains) tu be deti.tetl, \v In (her it may not b<- poisonous of itself; as lead is universally allowed to be, win n taken into the stomach. The large quantities of tin, which are someiin es given in medicine with much safety, and the con. stant use which our ancestors made of it in plates and dishes, before the ii.tru tiction of china or other earthen ware, without experi. pacing any mischief, render all other proof of the innocent nature of pure tin superfluous. And hence it may be proper to add a few observations concerning the purity of tin. The ores of metallic substances often contain more substances than that particular one from which they receive their denomina- tion. M. Kller, of Berlin, had in his collection an ore, -which con. tained gold and silver, and iron and quicksilver, closely united tog< ther in the same mass. Lead ore, it has been remarked, so often contains silver, that it is seldom found without it ; it is often also mixed with a sulphureous pyrites, which is a sort of iron ore, and with blackjack, which is an ore of zinc ; so that lead, and silver, and iron, and zinc, are commonly enough to be met with in the same lump of lead ore. Tin ore, in like manner, though it is sometimes unmixed, is often otherwise; it frequently contains botli tin, and iron, and copper. The lire with which tin ore is smelted, is sufficiently strong to smelt the ores of the metals which are mixed with it ; and hence the reader may understand, that, •without any fraudulent proceeding in the tin smelter, there may be a variety in the purity of tin, which is exposed to sale in the same country; and this variety is still more likely to take place, in spe- cimen- of tin from different countries, as from the East Indies, from England, and from Germany. This natural variety in the purity of tin, though sufficiently discernible, is far less than that which is fraudulently introduced. Tin is above five times as dear TINNING COPPER, &C. 997 as lead ; and as a mixture consisting of a large portion of tin with a small one of lead, cannot easily be distinguished from a mass of pure tin ; the temptation to adulterate tin is «r»'at, and the fear of detection small. In Cornwall, the purity of tin is ascertained, before it is exposed to sale, by what is called its coil-age: the tin, when smelted from the ore, is poured into quadrangular moulds of stone, containing about 320 pounds weight of metal, which, when hardened, is called a block of tin ; each block of tin is coined in the following manner: — " The officers appointed by the D>;ke of Cornwall as" at Musschenbroeck, who was many years professor of natural philosophy at Utrecht, puts the specific gravity of what he calls pure tin equal to 73iO, but that of English tin, and he has been followed by Wallerius, equal to 7471 + ; for it will appear presently, that such sort of tin must have contained near one.tenth of its weight of lead. » Borlase'sNat Hist, of Cornw. p. 183. + Newman's Chem. by Lewis, p. 89. J Mu>schen. Ess. de Phys. 1739. French Trans. Wallerii Min vol. I. p. 154. There is a very good Table of Specific (.'r.i\it:.>, ;"ilj!i3hcd i. r, • tn , ml vo- lume i.f Mu-Mhenbroeck's Intruductio ail I'hiln- p.'im .V//H/- ;n, I7'"»;, in which the author does more justice to J-inglish ounce* a cubic lV,ort which-is the lightest of all the tins which he examined. £98 TINNING COPPER, &.C. Weight of a cubic foot of English tin, according to different authors. Cotes, Ferguson, Emerson 7320 oz. avoir. Boerhaavt-'s Chem. by Shaw 7311 Musschenbroeck & Wallerius 7471 Martin — — — 7550 From the following experiments it may appear probable, that not one of these authors, in estimating the specific gravity of tin, has used the purest sort, but rather a mixture of that with lead, or some other metal. A block of tin, when it is heated till it is near melting, or after being melted, and before it becomes quite fixed, is so brittle that it may be shattered into a great many long pieces like icicles, by a smart blow of a hammer* : tin in this form is called by our own manufacturers grain tin, by foreigners virgin tin, or tears of tin ; and they tell us, that its exportation from Britain is prohibited under pain of deatht. The tin which I used in the following ex- periments, was of this sort, but I first melted it, and let it cool gra- dually ; a circumstance, I suspect, of some consequence in de. determining the specific gravity not only of tin, but of other me. tals. I have put down in the following table., the specific gravity of this tin, and of the lead I mixed with it by fusion, and of the several mixtures when quite cold ; the water in which they were weighed was fiOp. Weight of a cubic foot of lead, tin, &c. Lead — — 1 1270 oz. avoir. Tin — - 7170 Tin 32 parts, lead 1—7321 Tin 16 — lead 1—7438 Tin 10 — lead 1—7492 Tin 8 — lead 1—7560 Tin 5 — lead 1—7645 Tin 3 — lead 1—7940 Tin 2 — lead 1—8160 Tin 1 — lead 1—8817 • This property is riot peculiar to tin; 1 have seen masses of lead which, nnder similar circumstances, exhibited similar .-ipp. -arancjcs ; and it has been observed, that zinc, when heated till it is just ready to be fn-ol, i- brittle. f Ency. Fran, and Mr. Baumc calls it " etain en roche, a cau c qne sa forme TINNING COPPEK, &C. 299 Blocks of tin are often melted by the pewterers into small rods ; I think the rods are not so pure as the grain tin ; at least, I found that a cubic foot of the specimen I examined, weighed 7246 ounces: but even this sort exceeds in purity any of the kinds ex- amined by the authors above mentioned. Chemistry affords cer- tain methods of discovering the quantity of lead with which tin is alloyed, but these methods are often troublesome in the applica- tion ; an enlarged table, of the kind of which 1 hare here given a specimen, will enable us to judge with sufficient precision of the quantity of lead contained in any mixture of tin and lead, of which we know the specific gravity. Pewterers, however, and other dealers in tin, use not so accurate a method of judging of its pa. rity, but one founded on the same principle ; for the specific gra- vities of bodies being nothing but the weights of equal bulks of them, they cast a bullet of pure tin, and another of the mixture of tin and lead, which they want to examine, in the same mould ; and the more the bullet of the mixture exceeds the bullet of pure tin in weight, the more lead they conclude it contains. Pewter is a mixed metal ; it consists of tin united to small por- tions of other metallic substances, such as lead, zinc, bismuth, and the metallic part, commonly called regulus of antimony. We hare three sorts of pewter in common use; they are distinguished by the names of plate — trifle — ley. The plate pewter is used for plates and dishes ; the trifle chiefly for pints and quarts ; and the ley. metal for wine measures, &c. Our very best sort of pewter is said to consist of 100 parts of tin, and of 17 of regulus of anti- mony,* though others allow only 1O parts of regulus to 100 of tint ; to this composition the French add a little copper. Crude antimony, which consists of nearly equal portions of sulphur and of a metallic substance, may be taken inwardly with great safety ; but the metallic part, or regulus, when separated from the sulphur, is held to be very poisonous. Yet plate pewter may be a very in. nocent metal, the tin may lessen or annihilate the noxious qualities of the metallic part of the antimony. We have an instance some, what similar to this in standard silver, the use of which has never rcsscmble a des stalactites;" he say* also, that its exportation is> prohibited, but that he does not see the reason for the prohibition, as it is not more pure than Cornish tin: and in this observation he ii right, it is nothing but Cornish tin in a particular form. Ch\m. par M. Baumc, vol. III. p. 422 * Med. Trans, vol. I. p. 286. + Petnb. Chem. p. 329. "00 TINNING COPPER, &C. been esteemed unwholesome, notwithstanding it contains near one- twelfth of its weight of copper. Though standard silver has al- ways been considered as a safe metal, whtn used for culinary pur. poses ; yet it is not altogether so, the copper it contains is liable to be corroded by saline substances into verdigris. This is fre- quently seen, when common salt is sufk-red to stay a few days in silver saltcellars, which have not a gold gilding; and even saline draughts, made with volatile salt and juice of lemons, hare been observed to corrode a silver tea-spoon, which had been left a week in the mixture. The weight of a cubic foot of each of these sorts of pewter is, Plate — 7248 Trifle — 7359 Ley 7963 If the plate pewter be composed of tin and regulus of antimony, there is no reason to expect, that a cubic foot of it should be hea- vier than it appears to be ; since regulus of antimony, according to the different ways in which it is made, is heavier or lighter than pure tin. A very fine silver-looking metal is said to be composed of 100 pounds of tin, 8 of regulus of antimony, 1 of bismuth, and 4 of copper. The ley pewter, if we may judge of its composition by comparing its weight with the weights of the mixtures of tin and lead, mentioned in the table, contains not so much as a third, but more than a fifth part of its weight of lead ; this quantity of lead is far too much, considering one of the uses to which this sort of pewter is1 applied ; for acid wines will readily corrode the lead of the flagons, in which they are measured, into sugar of lead ; this danger is not so great with us, where wine is seldom fold by the measure, as it is in other countries where it is generally sold so, and their wine measures contain, probably, more lead than ours do. Our English prwterers have at all times made a mystery of their art ; and their raufion was formerly so much encouraged by the legislature, that an act of parliament was passed, rendering it unlawful for any master pewterer io fake an apprentice, or to em. ploy a journeyman, who was a foreigner. In the pn-Miit improved >i (li'in'st'\, i!::s r.'u"!>M is useless ; since any one tolerably skii.ed in (hat scimce, would be able to discover the quality and quantity of the metallic cci in any particular sort of pewter ; and it is not only useless now, but one would have thought it must have been always so; whilst tin, the principal ingredient, TINNING COPPER, 8CC. 301 was found in no part of Europe in so pure a state, nor in so great plenty a> in KnJ MI . Burlasc and I'ryce, who have written so minutely on the method of prepirin;; the tin in <>r w.r'. ire both of them silent, as to any operation 'h<- tin un is coinage; but aivin* us, uut t)i it llowg. from (he ore. i- la '. .i into troughs, each of which contains a') ut three hun.'rid pounds weight of metal, called slabs, blocks, or pieo ir ntn'fh s ze tnd form it i-> so d in every market in is. however, in general assert, that our tin as exported is a mixed metal ; and the French Encyclopedists in par. ticular (article Ctain) inform u>, on the authority of Mr. llouelle, that the virgin tin is again malted and cast into iron moulds of half afoot in thickness; that the metal is .cooled very slowly; that when cold it is divided horizontally into three layers ; that the up. permost, being very soft pure tin, is afterwards mixed with cop. per, in the proportion of 3 pounds of copper to 100 of tin ; that the second layer, being of a harsher nature, has 5 pounds of lead added to 100 of the tin ; and that the lowest layer is mixed with 9 pounds of lead to an hundred of the tin ; the whole is then re. melted, and cooled quickly ; and this, they say, is the ordinary tii\ of Knglaud : and Geoffroy had formerly given much the same ac- count*. There is, probably, no other foundation for this report, but that pewter has been mistaken for tin, these metals being some. times calli.d by the same name; and fine pewter being sometimes made from a mixture of 1 part of copper with 20 or 30 parts of tin. The mixture generally used for the tinning of copper vesselsi consists of 3 pounds of lead, and of 5 pounds of pewter ; when a finer composition is required, ten parts of lead are mixed with six- teen of tin ; or one part of lead with two of tin: but the proportions in which lead and tin are mixed together, even for the same kind of work, are not every where the same; different artists having dif. * — f'isores aperto furni osliolo, me tallum in fonnas qiiasdam ex arena paratas difiluerc sinunt, ibiquc in massas grandiores concrescit. Superior stannese mas -IT. pars adeo molds est et flexili-. ut sola eluboruri nequeat sine cuprt miHela, trium scilicet lihrarum super stanni libras centum. Ma'ije |>ari media binas un'um rupri libras recipit. lotiroa vero adeo fragihs < *t et in- tractabilis, ut cum liujus metalli centum lit>ri» plumbi libra* octudecim con- tociare oporteat. Geoff. Mat. Med. vol. I. p. *«. 302 TINNING COPPER, &C. ferent customs. Vessels tinned with pure tin, or with (he best kind of pewter, which contains no lead, do not stain the fingers •when rubbed with them : whilst those which are tinned with com. position, into which lead enters as a constituent part, colour the fingers with a blackish tinge. Zinc was long ago recommended for the (inning of copper ves. sels, in preference both to the mixture of tin and lead, and to pure tin* : and zinc certainly has the advantage of being harder than tin, and of bearing a greater degree of heat before it will be melted from the surface of the copper; so that on both these ac- counts it would, when applied on the surface of copper, last longer than tin ; just as tin, for the same reasons, lasts longer than a mix. ture of tin and lead. But whether zinc makes any part of the com- pound metal for tinning copper, so as to prevent the necessity of repeated tinning, for which a patent was granted some years ago, is what I cannot affirm. Whatever may the excellence of that composition, or of any other composition, which may be invented with respect to its durabilily, and its not contracting rust ; still it ought not to be admitted into general use, till it has been proved, that it is not soluble in vegetable acids, or that its solutions are not noxious+. A method has of late years been introduced at Rouen, of applying a coat of zinc upon hammered iron sauce, pans. The vessels are first made very bright, so that not a black speck can be seen ; they are then rubbed with a solution of sal ammoniac, and afterwards dipped into an iron pot full of melted zinc, and being taken out, the zinc is found to cover the surface of the iron ; and if a thicker coat of zinc is wanted, it may be ob- tained by dipping the vessel a second time. This kind of covering is so hard, that the vessels may be scoured with stand without its being rubbed off J. Kitchen utensils, which are made of cast iron, are usually tinned to prevent the iron's rusting ; and, as great improvements have been lately made in rendering cast iron mallea- ble, it is not unlikely, but that tinned iron vessels may become of general use. • Mem. de V Arad. des Scit-n. a Par. 1142. •f- This doubt with respect lo zinc is said to have been removed.— M. dp la Planche, a physician at Paris, tried the experiment on himself: he took the tall* of zinc, formed by the vegetable ar ids, in a much stronger dose than the aliments prepared in copper vessels, lined with zinc, could have contained, and he felt no dangerous effVcts from them. Fourcroy's Chem. vol. I. p. 442. f Jouro. de Phy. Decoem. 1778. TINNING COPPFR, &C. 303 The common method of tinning consists in making the surface of the copper vessel quite bright, by scraping it, and by washing it with a solution of sal ammoniac ; it is then heated, and the tin, or metallic mixture designed for (inning, is melted, and poured into it, and being made to flow quickly over every part of the sur- face of the vessel, it incorporates with the copper, and, when cold, remains united with it. Rosin or pitch is sometimes used, to pre. vent the tin from being calcined, and the copper from being scaled, either of which circumstances would hinder the sticking of the tin. I had the curiosity to estimate the quantity of pure tin, which is used in tinning a definite surface of copper. The vessel was ac. curately weighed before and after it was tinned, its surface was equal to 254 square inches ; its weight, before it was tiniu-d, was 46 ounces, and its weight, after the operation, was barely 464 ounces; so that half an ounce of tin was spread over 254 square inches, or somewhat less than a grain of tin upon each square inch. How innocent soever pure tin may be, yet the tenuity of the coat of it, by which copper vessels are covered, in the ordinary way of tinning, cannot fail to excite the serious apprehensions of those who consider it; for in the experiment which I have mentioned, the tin was laid on with a thicker coat than in the common way ; instead of a grain, I suspect that not a quarter of a grain of tin is spread over a square inch in the common way of tinning. A dis. covery has been lately made at Paris of a method of giving to cop. per or iron a coat of any required thickness, by tinning them ; the composition used for the tinning is not mentioned ; but it is said that a piece of copper, which in the common way of tinning only absorbed 21 grains of tin, absorbed of the new composition 432 grains, or above twenty times as much*. Till this discovery is generally known, our workmen should study to cover the cop. per with as thick a coat as they are able of pure tin. The dan- ger from the corrosion or solution of the tin by vinegar, juice of lemons, or other vegetable acids, if any at all, cannot it is appre- hended, be sensibly felt, except in very irritable habits, or where sour broths, sauces, or syrups, are suffered to stand long in tinned vessels before they are used. And, indeed, a pro. per attention to keeping the vessels clean, mi^ht render the use of copper^itself, for the boiling of food, especially of animal food, * J. 'Esprit An Jonrnaox, Mai, 1785. 304 TINNING COPPER, &C. •wholly safe. The French may be allowed to excel us in cookery, but »e probably excel them in cleanliness; fur the melancholy accidents attending the use of copper Tessels, are murh less fre. quent in Filmland thun in France \ and this difference proceeds, I conjecture, from the superior care of the English in keeping their vessels clean, and from the cheapness and purity of the tin w> in tinning copper. VN e are not certain that the-art of tinning copper vessels was known to the Jews, when they came out of Egypt ; the vessels used in the temple service were made of cop. per by divine appointment, and by being constantly kept clean, no inconveniences followed. The wort, from which malt liquor is brewed, is boiled in copper vessels; the distillers and confectioners prepare their spirits and syrups in un-tinncd vessels of the same metal, without our suffering any thing in our health from t practices ; at least, without our being generally persuaded that we suffer any thing. A new copper vessel, or a copper v- newly tinned, is more dangerous than after it has been used : be. cause its pores, which the eye cannot distinguish, get filled up M ifh the substances which are boiled in it, and all the sharp < of the prominent parts become blunted, and are thereby rendered less liable to be abraded. M. de la Lande, in describing the cabinet at Portici, observes, that the kitchen utensils, which have been dug up at Herculaneum, are almost all of them made of a compound metal like our bronze, and that many of the vessels are covered with silver, but none of them with tin : and hence he concludes, that the useful art of ap. plying tin upon copper, was unknown to the Romans ; " cet art utile d'appliquer 1'etain sur le cuivre manquoit aux Remains*." By the same mode of arguing, it might be inferred, that whatever is not met with in one house or town, is not to be found in a whole country : yet should a town in England, in which there happened to be plenty of tinned, but no plated or silvered copper, be swal. lowed up by an earthquake, a future antiquary, employed in dig- ging up its ruins, would make a bad conclusion, if he should thence infer, that the English understood, indeed, at that lime, the art of applying a covering of tin, but not one of silver upon copper. If the ingenious author had recollected what is said in the 34th book of Pliny's Natural History, he would have seen reason * Voyage d' uu Francois en Italic, vol. VII. p. 120. TINNINO COPPER, &.C. 305 to* believe, that the Romans, at least when Pliny wrote that book, did understand the method of tinning copper which is now in use; for this great naturalist assures us in express terms, that tin, smeared upon copper vessels, rendered the taste more agreeable, and restrained the virulence of copper rust. It is to no purpose to object, that the tin (stannum) of Pliny was a substance different from our tin ; for though it should be in some measure granted that it was a mixture of lead and silver, yet the same author tells us, in the same place, that white lead (plumbum album), by which it is universally allowed our tin is meant,* was so incorporated with * Mr. Good, while he acknowledges that by plumbum album was generally meant tin, informs us that by the same term pewter, or a mixture of lead and tin, was also occasionally intended. The passage we refer to is in his note upon Lucretius. VI. 579. Denique, et auro res aurum concopulat una, JGrique aes PLUMBO fit utei jungatur ab ALSO* One cement sole with gold concentrates gold, And nought but PEWTER brass with brass unites. The cement here referred to, says he, is doubtless, the chrysocella, a mineral sand, found on the shores of the Red Sea, of an elegant green colour, deno- minated by the natives of modern times linear, or tincal. The borax, now in use for similar purposes, does not differ essentially from the chrysocolla, when dissolved and crystalised, and is, by some chemists, supposed to be precisely the same. Pewter i?, in the present day, the common solder for copper and brass: it is generally a combination of tin, lead, and regulus of antimony. From the lead employed in the manufacture, and the splendid whiteness of its appear* ance when too much lowered or adulterated, it is here happily denominated by our poet plumbum album ; literally " white lead :" and by this term it is erroneously translated by Guernier. I say, erroneously ; for the cerusse, or white lead of modern days, is no solder whatever in metallic preparations. Creech omits the verse entirely, and thus dexterously runs away from the dif- ficulty. De Coutures is wrong in the whole passage : " 1'argent," says he, " est allie avec Tor, et 1'airain avec le plomb." " Silver unites itself with gold, and brass with lead." Marchetti is quite correct : con lo stagno il rame Si salda al ramc. I most leave it to the chemists to determine what substance was employed formerly, instead of the regulus of antimony ; or whether the ancients were acquainted with a metal of this description, and its different powers in dif- ferent states of combination. Yet, probably, the plumbum album, or copper solder of the Romans, was a mixture of lead and tin alone. Since writing the above, I have met with an excellent memoir of M. Klap- roth, inserted in the Berlin Memoirs de 1' Academic Royale des Sciences, Vol. for 1792—1795; in which the author asserts, that the plumbum nigrum of the Romans was lead, and the plumbum album, candidum, or argcntarium, tin, or the nas-a-iTipev of tbe Greeks. There can be ao doubt that this appellation VOJ,. TI. X 306 TINNING COPPER, &C. copper by boiling, that the copper could scarcely be distinguished from silver. * Nay, it appears that the Romans not only used pur« tin, but the same mixture of tin and lead, which some of our work- men use at this time in tinning vessels. A mixture of equal parts of tin and lead, they called argentarium ; a mixture of two parts of lead and one of tin, they call tertiarium ; and with equal parts of tertiarium and tin, that is, with two parts of tin and one of lead, they tinned whatever vessels they thought fit. They, moreover, applied silver upon copper, in the same way in which they applied tin upon it ;+ and they used this silvered copper (I do not call it plafed, because copper is plated by a different process) in ortoa. men ting, their carnages, and the harness of their horses, as we now use plated copper ; on this head Pliny observes, and a rigid phi- losopher will apply the observation to ourselves, that such was the luxury of the Romans, that it was then simply reckoned a piece of elegance to consume in the ornaments of coaches, and in the was generally applied to tin alone ; but as this metal, when employed simply, will be fmind a very indifferent solder for copper, it is obvious, that the plum* bum album of our poet, and of the Roman coppersmiths in general, must also have included a compound of tin with lead, or some other metal, as well at pure unmixed tin* M. Klaproth, who has paid much attention to numismatic analysi?, has discovered that the coins of Magna Grsecia and Sicily consisted of copper, alloyed with from an eighth to a twelfth part of lead, and half as much of tin. The Roman coins he has at times found to have been formed of pure copper; and occasionally with an alloy of one-fourth, or one-sixth, part of zinc, and a small portion of tin. The ancients were only acquainted with zinc in its ore, which is calamine ; their brass was denominated aurichalcum, and was a compound of calamine and copper. Zinc, as a semi-metal, was not known till its discovery by Albertus Magnus, in the 13th century. According to Aristotle, the Greeks acquired their knowledge of converting copper into bras*, or aurichalcum, from a people who inhabited the borders of the Euxine sea, whom he denominates Mossynseci ; and it is from this word M. Klaproth derives the term messing, which is the German appellation for brass. [Editor. * Slannum illitum aeneis vails, saporem gratiorum rcddit, et compescit aeru- ginis virus, mirumque, pondus non auget — from the copper not being sensibly increased (for Pliny here speaks popularly), we may infer, that the covering of tin which the copper received was very slight, and the art alluded to by Pliny in this place, was probably the same with that of tinning now in use— album (scil. plumbum) incoquitur aereis operibus, Galliarum invento, ita ut vix discern! possit ah argento, eaque incoctilia vocant. This description seems to be expressive of the manner of tinning, by putting the copper into melted tin, as is practised in the tinning of iron plates. Plin. Hist. Nat. L. XXXIV. S. XLIII. t deinde et argentum incoquere simili modo ccepere equorum maxime ornameotii, &c. Id. ib. TINNING, PLATING, &C. 307 trappings of horses, metals, which their ancestors could not use in drinking vessels, without being astonished at their own prodigality : we are not yet, however, arrived at the extravagance of Nero and his wife, who shod their favourite horses with gold and silver. Pliny mentions an experiment as characteristic of tin — that when melted and pouted upon paper, it seemed to break the paper by its weight, rather than by its heat; and Aristotle, long before Pliny, bad remarked the small degree of heat which was requisite to fuse Celtic (British) tin.* This metal melts with less heat than any other simple metallic substance, except quicksilver ; it re- quiring for its fusion not twice the heat in which water boils ; but compositions of tin and lead, which are used in tinning, melt with a still less degree of heat, than what is requisite to melt simple lin : and a mixture composed of 5 parts of lead, 3 of tin, and 8 of bis. muth, though solid in the heat of the atmosphere, melts with a less degree of heat, than that in which water boils. [Watson's Chemical Essays. SECTION I. Of tinning iron— Of plating, and gilding copper. IBON is tinned in a different manner from copper. In some foreign countries, particularly in France, Bohemia, and Sweden, the iron, plates, which are to be tinned, are put under a heavy hammer which gives in some works, 76 strokes in a minute : they can in one week, with one hammer, fabricate 43-20 plates ; the iron is heated hi a furnace eight times, and put eight times under the hammer during the operation, and it loses near an eighth part of its weight. Iron and copper are both of them very apt to be scaled by being heated, and they thereby lose greatly of their weight. Twenty.four hundred weight of pure plate copper will not, when manufactured into tea-kettles, pans, &c. give above twenty- three hundred weight. Twenty one hundred weight of bar iron will give a ton, when split into rods; but taking into consideration all iron and steel wares, from a needle to an anchor, it is estimated that thirty hundred of bar iron will, at an average, yield a ton of wares. + ''•'''___ » DeMirab. t See an instrucfiTe pamphlrt, intitled, A Reply to Sir L. O'Briea, by W. Gibbooi, 1785. x 2 TINNING, PLATING, &C. Thirty hundred weight of cast iron is reduced to twenty, when it is to be made into wire ; and twenty. six to twenty-two, when it is to be made into bar iron. Steel suffers much less loss of weight in being hammered, (han iron does. Cast steel does not lose above two parts, and bar steel not above four, in one hundred, when drawn into the shape of rasors, files, &c. The iron plates in England are not hammered, but rolled to proper dimensions by being put between two cylinders of cast iron, cased with steel. This me- thod of rolling iron is practised in Norway, when they form the plates with which they cover their houses j but whether it was in- vented by the English, or borrowed from some other country (as many of our inventions in metallurgy have been, especially from Germany), I have not been able to learn. In the first account which I have seen of its being practised in England, it is said to have been an invention of Major Hanbury at Pontypool ; the ac. count was writen in 1697, and many plates had then been rolled*. The milling of lead, however, which is an operation of the same kind, had been practised in the year 1670 ; for an act of parlia. ment was passed in that year, granting unto Sir Philip Howard and Francis Watson, Esq. the sole use of the manufacture of milled lead for the sheathing of ships. A book was published in 1691, intitled, The New Invention of Milled Lead for sheathing of Ships, &c. It appears from this book, that about twenty ships, belonging to the navy, had been sheathed with lead ; but the prac. tice was discontinued, on account of complaints of the officers of the navy, that the rudder irons and bolts under water had been wasted to such a degree, that in so short a space of time, as had never been observed upon any unsheathed and wood, sheathed ships. The persons then interested in sheathing with lead, published a sen. sible defence ; and among other things they remarked, that both the Dutch and the English had ever been in the habit of sheathing the stern-posts and the beards of the rudders with lead or copper ; and that the Portuguese and Spaniards did then sheath the whole bodies of their ships, even of their gallions, with lead, and had done it for many years. Copper sheathing has since taken place in the navy ; but it is said to be liable to the same objections which were, above a century ago, made to lead sheathing. It is prefer, able, however, to lead, on account of its lightness. If the fact • Phil. Trans. Abr, Vol. V, TINNING, PLATING, &C. 309 should be once well established, that ships sheathed with lead or copper will not last so long as those which are unsheathed, or sheath, ed only with wood, it would be a problem well deserving the con. sideration of chemists, to inquire into the manner how a metallic covering operates in injuring the construction of the ships, and whether that operation is exerted on the iron bolts, or on the tim. bers of the ship. When the iron plates have been cither ham- mered or rolled to a proper thickness, they are steeped in an acid liquor, which is produced from the fermentation of barley meal, though any other weak acid would answer the purpose; this steep* ing, and a subsequent scouring, cleans the surface of the iron from every speck of rust or blackness, the least of which would hinder the tin from sticking to the iron, since no metal will combine itself with any earth, and rust is the earth of iron. After the plates have been made quite bright, they are put into an iron pot filled with melted tin ; the surface of the melted tin is kept covered with suet or pitch, or some fat substance, to prevent it from being cal. cined ; the tin presently unites itself to the iron, covering each side of every plate with a thin white coat : the plates are then taken oot of the melted tin ; and undergoing some further operations, which render them more neat and saleable, but are not essential to the purpose of tinning them, they are packed up in boxes, and are every where to be met wilh in commerce under the name of tin- plates, though the principal part of their substance is iron ; and hence the French have called them for blanc, or white iron : Sir John Pettus says, that they were with us vulgarly called lat ten ; though that word more usually I think denoted brass. Tin is not, but iron is, liable to contract rust by exposure to air and moisture, and hence the chief use of tinning iron is to hinder it from becoming rusty j and it is a question of some importance, whether iron of a greater thickness than the plates we have been speaking of, might not be advantageously tinned. I desired a workman to break off the end of a pair of pincers, which had been long used in taking the plates out of the melted tin ; the iron of the pincers seemed to have been penetrated through it's whole sub- stance by the tin ; it was of a white colour, and had preserved it's malleability. It is usual to cover iron stirrups, buckles, and bri- dle bits, with a coat of tin, by dipping them after they are made, ioto melted tin ; and pins, which are made of copper wire, are 310 TINNING, PLATING, &C. whitened, by being boiled for a long time with granulated tin in a lye made of allum and tartar. Would the iron bolts used in ship, building be preserved from rusting by being long boiled in melted tin ? — Would it be possible to silver iron plates by substituting melted silver for melted tin ? I do not know that this experiment has ever been tried ; but an intelligent manufacturer will see many advantages which would attend the success of it. It is customary, in some places, to alloy the tin, used for tinning iron plates, with about one.seventieth part of its weight of copper : foreigners make a great secret of this practice : I do not know whether any of our manufacturers use copper ; some of them I have reason to believe do not. Too much copper renders the plates of a blackish hue j and if there is too little, the tin is too thick upon the plates ; but this thickness, though it may render the plates dearer, or the profit of the manufacturer less, will make them last longer. When the tin is heated to too great a pitch, some of the plates have yellowish spots on them ; but the coat of tin is thinner and more even, when the tin is of a great, than of a moderate heat; and the yellowness may be taken away, by boiling the plates for two or three minutes in lees of wine ; or, where they cannot be had, sour small beer, or other similar liquors, may, probably, be used with the same success. The quantity of tin used in tinning a definite number of plates, each of a definite size, is not the same at different manufactories. In some fabrics in Bohemia, they use fourteen pounds weight of tin for making three hundred plates, each of them being eleven and one.third inches long, by eight and a half broad ; according to this account, one pound of tin covers a surface of twenty .eight and one.third square feet: in other, where the tin is laid on thicker, one pound will not cover above twenty. two square feet ; the thickness of the tin, even in this case, is small, not much exceeding the one-thousandth part of an inch -, though that is near twice the thickness which tin has upon copper in the ordinary way of tinning. I have inquired of our English manufacturers concerning the quantity of tin used by them iu co- vering a definite surface of iron ; and from what 1 could collect, it is very nearly the same with that used in Bohemia, from whence we derived the art of tinning, or twenty-eight square feet to a pound of tin. There are various tin plate manufactories established of late TINNING, PLATING, &C. 311 years in different parts of England and Wales. Saxony a>d part of Bohemia formerly supplied all the known world with the com. nodity ; but England now exports large quantities of it to Holland, Flanders, France, Spain, Italy, and other places. About the year 1670, Andrew Yarrington, (he deserves a statue for the at. tempt) undertook, at the expence of some enterprizing persons, a journey into Saxony, in order to discover the art of making tin plates : he succeeded to his utmost wishes ; and, on his return, several parcels of tin plates were made, which met the approbation of the tin-men in London and Worcester*. Upon this success, preparations were made for setting up a manufactory, by the same persons who had expended their money in making the discovery ; but a patent being obtained by some others, the design was aban- doned by the first projectors, and the patentees never made any plates ; so that the whole scheme seems to have been given up till the year 1720, when the fabricating of tin plates made one of the many very useful projects (though they were mixed with some which were impracticable) for which that year will ever be memo, rable. How soon after that year the manufacture of tin plates gained a lasting establishment, and where they were first made, are points on which I am not sufficiently informed ; an old Cambridge workman has told me, that he used them at Lynn, in Norfolk, in the year 1 730, aud that they came from Pontypool. The tin. men, at the first introduction of the English plates, were greatly delighted with them ; tKy had a better colour, and were more pliable than the foreign ones, which were then, and still continue to be ham. mered ; it being impossible to hammer either iron or copper to so uniform a thickness, as these metals are reduced to by being rolled. It is said that a Cornish tin.man flying out of England for a mur. der in 1243, discovered tin in Saxony, and that before that disco- very, there was no tin in Europe, except in England i ; a Romish priest, converted to be a Lutheran, carried the art of making tin plates from Bohemia into Saxony, about the year 1620 J ; and An. drew Yarrington, as we have seen, brought it from Saxony into England about the year 1670 ; Saxony at that time being the only place in which the plates were made. They are now made not * England's Improvement by Sea and Land, by Andrew Yarrington, Gent. 1698. + Heylin's Gtof . t Yairinfton. x4 312 TINNING, PLATING, &C. only in England, but in France* Holland, Sweden, &c. though from the cheapness of our tin, and the excellency of some sorts of our iron, the greatest share of the tin plate trade must ever center with ourselves. Our coal is another circumstance which tends to give Great Britain an advantage over some other coun. hi' s, in such manufactures as require a great consumption of fuel. Wood was scarce in Saxony about a century ago, and it is now still more scarce in France. They are beginning, it is said, in that country, to use coal and coak, or chirnd j it. coal, called by them charbon de terre epur6, and they have grunted a patent to an individual for the preparation of it*. Another individual has begun to distil tar from pit-coal, and he gets about five pounds weight of tar from an hundred of coal (which is pretty nearly what I suggested, in 1781, as possible to be obtained from the same quantity, Vol. II. p. 352). The French + expect great ad- vantage from this mode of depurating coal : but we have nothing to apprehend on that score ; for the patriotic zeal of the Earl of Dundonald has put us in possession of every advantage which can be expected from, a discovery, which he has had the honour of bringing to perfection. The plating of copper is performed in the following manner: Upon small ingots of copper they bind plates of silver with iron wire, generally allowing one ounce of silver to twelve ounces of copper. The surface of the plate of silver is not quite so large as that of the copper ingot ; upon the edges of the copper, which are not covered by the silver, they put a little borax ; and exposing the whole to a strong heat, the borax melts, and in melting contri. butes to melt that part of the silver to which it is contiguous, and to attach it in that melted state to the copper. The ingot, with it's silver plate, is then rolled under steel rollers, moved by a water wheel, till it is of a certain thickness ; it is afterwards further * Acad des Scicn. a Paris, 1781 ; where M. Lavoisier gives an useful me- moir on the comparative excellencies of pit-coal, coak, wood, and charcoal, as fuels. — II suit de ces experiences, que pour produire des effets egaux, il faut employer : charbon de terre 660 livret ; charbon de terre charbonne 552 ; rharbnn de boi« me!6 960 ; bois de hfilrff 1 125 ; bois de cliene 1089. t II suffit dc dire qu'clle peut fournir A la capitale un nouveau cliauflage, de- vcnu n6cessuire dans un moment ou 1'on est monact d'une disette de bois; qu'elle pent oiivrir dans le royaume une nouvelle brancc de commerce ; etablir de noDvelles manufactures; faire valoir des mines, restccs jusqu'a present inn- tiles.— L'Esprit des Journ. Jmllet, 1785. TINNING, GPLATING, &C. 313 rolled by hand rollers, to a greater or less extent, according to the use for which it is intended ; the thinnest is applied to the lining of drinking horns. One ounce of silver is often rolled out into a sur- face of about three square feet, and its thickness is about the three thousandth part of an inch ; and hence we need not wonder at the silver being soon worn off from the sharp angles of plated cop- per, when it is rolled to so great an extent. Plated copper has, of late years, become very fashionable for the mouldings of coaches, and for the buckles, rings, &c. of horse harness. It might be used very advantageously in kitchen utensils, by those who dislike the use of tinned copper, and cannot afford to be at the expence of silver saucepans., &c. The silver, instead of being rolled on the copper to so great a thinness as it is in most works, might be left in kitchen furniture considerably thicker, so that an ounce of sil. ver might be spread over one square foot ; the silver coating would in this case still be very thin, yet it would last a long time. Fire does not consume silver, and the waste in thickness, which a piece of plate sustains from being in constant use for a century, is not much.; as may be collected from comparing the present weight of any piece of college plate, which has been daily used, with the weight it had an hundred years ago. I do not know whether any attempt has ever been made to plate copper with tin instead of silver ; I am aware of some difficulty, which might attend the operation; but yet it might, I think, be performed ; and if it could, we might then have copper vessels covered with a coat of tin of any required thickness, which is the great desideratum in the present mode of tinning : but it ought to be remarked, that the thicker the coat of tin the more liable it would be to be melted off the copper by strong fires. The art of plating copper has not been long practised in Eng- land ; nor do I know whether it was practised at an early period in any other country ; for the Roman method of silvering copper was different, I think, from that now in use. Thomas Bolsover of Sheffield, in the year 1742, was the first person in Eng- land who plated copper ; it was applied by him to the purposes only of making buttons and snuff-boxes: soon after it was used for various other works : a person of the name of Hoy land, at Sheffield, was the first who made a plated candlestick. What is commonly called French plate, is not to be confounded with the plated copper of which we have been speaking; for though 314 TINNING, PLATING, &C. both these substances consist of copper covered with a thin coat of real silver, yet they are not made in the same way. In making French plate, copper, or more commonly brass, is heated to a cer- tain degree, and silver leaf is applied upon the heated metal, to which it adheres by being rubbed with a proper burnisher. It is evident, that the durability of the plating must depend on the num. ber of leaves which are applied on the same quantity of surface. For ornaments which are not much used, ten leaves may be suffici- ent; but an hundred will not last long, without betraying the me. tal they are designed to cover, if they be exposed to much hand, ling, or frequently washed. After the same manner may gold leaf be fixed, either on iron or copper. Gold is applied on silver, by coating a silver rod with gold leaf; and the rod being afterwards drawn into wire, the gold adheres to it ; the smallest proportion of gold, allowed by act of parliament, is 100 grains to 576O grains of silver j and the best double-gilt wire is said to have about twenty grains more of gold to the same quantity of silver*. It has been calculated, that when common gilt wire is flatted, one grain of gold is stretched on the flatted wire to the length of above 401 feet, to a surface of above 100 square inches, and to the thinness of the 492090th part of an inch : and M. de Reaumur says, that a grain of gold may be extended to 2900 feet, and co- ver a surface of more than 1400 square inches ; and that the thick, ness of the gold, in the thinnest parts of some gilt wire, did not exceed the fourteen millionth part of an incht. The gold, when thus applied, is thinner than when silver is gilt in the following manner, which is yet reckoned one of the cheapest ways, and is used in making various toys. Gold is dissolved in aqua regia y and linen rags being dipped into the solution, they take up some particles of gold ; the rags being burned to ashes, and the ashes being rubbed on the silver, the gold adheres to it, and is rendered visible by being well burnished. • Lewis Com. Phil. p. 53. i Id. 60. [ 315 ) CHAP. V. GILDING IN OR MOULU; USE OF QUICKSILVER IN EX- TRACTING GOLD AND SILVER FROM EARTHS; EXPE- RIMENTS OF BOERHAAVE ON QUICKSILVER; SILVER- ING LOOKING-GLASSES, AND THE TIME WHEN THAT ART WAS DISCOVERED. J. HERE is another method of applying gold on copper or silver, which is much practised ; it is called gilding in Or Moulu. Quick. silver dissolves gold with great facility : if you spread a gold leaf (not what is called Dutch leaf, which is made of brass) on the palm of your hand, and pour a little quicksilver upon it, you will see the quicksilver absorbing the gold, just as water absorbs into its substance a piece of salt or sugar. Persons who have taken mercurial preparations internally, seldom fail to observe the readiness with which the mercury transudes through their pores, attaching itself to the gold of their watches, rings, sleeve-buttons, or ear-rings, and rendering them of a white colour. A piece of gold, of the thickness even of a guinea, being rubbed with quick- silver, is soon penetrated by it, and thereby made so fragile, that it may be broken between the fingers with ease : and if more quicksilver be added, the mixture will become a kind of paste, of different degrees of consistence according to the quantity of quick, silver which is used. A piece of this paste is spread, by ways well known to the artists, upon the surface of the copper which .1 to be gilded in or moulu, and the metal is then exposed to a proper degree of heat : quicksilver may be evaporated in a far less decree of heat, than what is required to melt either gold or cupper ; when therefore the mixture of gold and quicksilver is exposed to the action of fire, the quicksilver is driven off in vapour ; and the gold, not being susceptible of evaporation, remains attached to the surface of the copper, and undergoing the operations of burnish- ing, &c. too minute to be described, becomes gilt. This method of gilding copper, by means of quicksilver and gold, was known 316 USES OF gUICKSILVER, &C. to the Romans*. Quicksilver will not uuite with iron, yet by an easy operation, iron may be gilded in the same way that copper or silver may. The iron is first to be made bright, and then immers- ed in a solution of blue vitriol, its surface will thereby become covered with a thin coat of copper, and it will then admit the gild, ing as if its whole substance was copper. It is this property which quicksilver has of uniting itself with gold, and it does the same with silver, which has rendered it of such great use to the Spaniards in America. They reduce the earths or stones, containing gold or silver in their metallic states, into a very fine powder ; they mix this powder with quicksilver ; and the quicksilver, having the quality of uniting itself with every particle of these precious metals, but being incapable of con. tiacting any union with any particle of earth, extracts these me. tals from the largest portions of earth. The quicksilver, which has absorbed either gold, or silver, or a mixture of both, is se- parated from the substance it has absorbed by evaporation ; the quicksilver flies off in vapour, and the substance remains in the vessel used in the operation. We have no mines of mercury in England ; Sir John Pettus, indeed, says, that a little cinnabar is now and then met with in our copper mines ; and Mr. Pennant observes, that quicksilver has been found in its native state on the mountains of Scotland ; and I have been shewn a piece of clay, said to have been dug near Berwick, in which there were some mercurial globules : but there are no works at present, where mercury is procured in any part of Great Britain ; nor are there many mines of mercury in any part of the world. In the Philoso. phical Transactions for 1665, we have an account of the quicksil. ver mines of Idria, a town situated iu the country anciently called Forum Julii, now Padria de Friouli, subject to the regency, and included in the circles of the lower Austria, in Germany. These mines have been constantly wrought for above 280 years, and are thought, one year with another, to yield above one hundred tons of quicksilver. In Hungary also, there are mines which yield quick, silver, but not so copiously now as formerly. Alonso Barba men. » JEs inaurari argento vivo, aut certe hydrargyro, legititum erat. Plin. Hist. Nat. XXXIII. Pliny understood by argentum vivnm, native quicksilver, which is found in a fluid state in many mines ; and by hydrargyrum he under- stood quicksilver separated from its ore by fire ; they are the same substance. USES OP QUICKSILVER, &c. 317 tions some quicksilver mines in America, near Potosi *, which, he says, God Almighty provided to supply the loss of this mineral, which is very considerable in extracting the silver from the earths and stones with which it is mixed : but the mines of Almaden in Spain are the richest, and probably have been wrought for the longest time of any in the world. Pliny speaks of the cinnabar which the Romans, with so much jealousy, annually fetched from Spain, and it is very probable that they had it from Almaden. M. Jussieu informs us f, that in 1717 there remained above 1200 tons of quicksilver in the magazines at Almaden, after a great deal had been sent to Seville in order to be exported to Peru, where the quicksilver, which is lost in extracting the silver, is said to be at least equal in weight to the silver which is extracted. From 1574, when they began to register the quicksilver, which came to Potosi upon the king of Spain's account, to the year 1640, there had been received, according to Alonso Barba, 204,600 quintals, be- sides a vast quantity irregularly brought in upon other accounts. This application of quicksilver to the extraction of gold and silver from the earths in which they are found, has rendered the con. sumption of it far more considerable since the discovery of the American mines, than it was amongst the ancients. Hoffman forms a calculation, and concludes, that fifty times as much gold as quicksilver was annually extracted from the bowels of the earth : Cramer j admits the truth of this calculation, but insinuates a suspicion worth attending to— that mercury may often exist in mi. nerals, and yet not be discovered by miners ; since in the open fires in which minerals, whose properties are not known, are usually examined, the mercury would fly off in fume. Earths or mine, rals of any kind, containing mercury, are most accurately assayed by distilling them with iron filings ; but whether a mineral con- tains mercury or not, may be easily discovered, by strewing it when powdered, on a plate of hot iron, or on a hot brick covered with iron filings, and inverting over it a glass of any kind ; the mercury, if the mineral contains any, will ascend, and attach it. •elf in small globules to the side of the glass. Mercury is divided, by the writers of systems of mineralogy, into native mercury, and mercury mineralized by sulphur : native mercury is found in its • Treatise on Metals, &c. by Alonso Barba. Eog. Trans, p. 118. f Hist, de 1'Acftd, dei Scieu. 1719. * Ars Docim. Cram. Vol. I. 9. 131- 318 USES OF QUICKSILVER, &C, running state, and quite pure, as it is said (though this may be doubted, from the facility with which mercury dissolves gold, and silver, and other metals), in the mines of Idria, Almaden, &c. . it is more frequently, however, imbedded in calcareous earths, or clays of different colours, from which it may be separated either by trituration and lotion, the smaller globules coalescing by mu. tual contact into larger ; or by distillation. The running native mercury, which requires no process for its extraction is more es. teemed, and thought to have some peculiar properties which do not belong to that obtained by simple distillation, though they both come under the denomination of virgin mercury. Mercury mine- ralised by sulphur, is called cinnabar, which some say is an Afri- can word denoting the blood of a dragon *. Cinnabar is the most common ore of mercury ; it is found in an earthy form resembling red ochre, sometimes in an indurated state, and, though gene, rally red, it hath been observed of a yellowish or blackish cast , ft is mostly opaque, but some pieces are as transparent as a ruby. This ore consists of mercury and sulphur combined together in different proportions ; some cinnabars yielding as far as seven, others not three parts in eight of their weight of mercury. Sulphur and mercury, being both volatile in a small degree of heat, would rise together in distillation, unless some substance, such as quick- lime or iron filings, was added to the cinnabar, which by its supe- rior affinity, unites itself with and detains the sulphur : whilst the mercury, not being able to support the heat, is elevated in vapour, and condensed in various ways in different works. It sometimes happens, that the coarser cinnabarine ores are so much mixed with calcareous earth, that they require no addition in order to ef. feet the separation of mercury from sulphur ; this is the case in the mines of Almaden. The finer kinds of cinnabar, bearing B much higher price than mercury itself, are never wrought for mer- cury, but either used in medicine, or, when levigated, under the name of vermilion, ia painting; and often by the women as a sub. stitute for carmine, which is prepared from cochineal. Native cinnabars are often mixed with small portions of arsenical, vitriolic, or earthy substances, whence they become of uncertain or dan. gerous efficacy in medicine ; for this reason Geoffroy recommends the use of factitious cinnabar ; and the native, though formerly in great repute, has been left out of modern dispensatories. The finest cinnabar we know of is brought from Japan, though there • Vllmont dc Bomarc. USES OP OUICKSILVBR, &C. 319 is great reason to believe that the Dutch impose upon the world a home manufacture, under the name of Japan cinnabar : the trade for gold, copper, and cinnabar, to Japan is exceedingly lucrative, and I believe wholly, as to Europe, in the hands of the Dutch. Those who are acquainted with the difficulty of making chemi- cal experiments, will admire the great patience and industry with which Boerhaave investigated the nature of mercury. He was in. duced to undertake this task, from a desire of verifying or refut- ing the doctrines of the alchemists. These adepts had taught, that mercury was the matter of which all metals consisted ; and that if it could be cleansed from some original impurities, with which, even in its virgin state, they held it to be polluted, it would then become fit nutriment for the seed of every metallic substance- for, according to them, every. metal sprung from its peculiar seed, which, when it met with its proper pabulum, in a proper matrix, attended with a due fostering heat, by a vivifying principle multi- plied itself, and received an augmentation of parts, in a manner similar to that by which plants and animals are dilated in their di- mensions. The investigation of nature is infinite ; every age adds somewhat to the common stock, which renders the labours of pre- ceding ages wholly useless. We no longer trouble ourselves with the works of the alchemists which remain, nor do we regret such of them as have been devoured by time, or were burned by the order of Diocletian ; nay, even the Herculean labours of Boer- haave are become less interesting to us, and probably never would have been undertaken by him, had he been aware, that mercury would, in a proper degree of cold, become, like other metals, solid and malleable. In the Transactions of our Royal Society, for the year 1733, we meet with Boerhaave's first dissertation upon mer- cury : his first experiments respect the change which the purest mercury undergoes from continual agitation; he included two ounces, which had been distilled above sixty times, in a clean bottle, and fastening the bottle to the hammer of a fulling mill which was almost constantly going, found in about eight months time above one eighth of the fluid, splendid, insipid mercury. changed into a black powder, of an acrid brassy taste. He next digested mercury in a gentle heat, (180° of Fahrenheit's thermo- meter), and found it, in a few months, changed into a powder, si- milar to what had been produced by agitation : both these pow- ders in a greater degree of heat were revivified, or became run- 320 USGS OP QUICKSILVER, &C. nins; mercury again. He then inquired into the change which re. peated distillation could produce ; after each pperation he found a red acrid powder remaining in the retort ; and he observes, that this powder was as copiously separated, after the mercury had been above 500 times distilled, as at first ; and thence reasonably concludes, that it ought rather to be attributed to a change of the mercury itself, than to any impurity contained in it. This pow- der, like the preceding, by a superior degree of heat became run. ning mercury ; except about a seventy-second part, which, though fixed in a strong fire, and verifiable with borax, could not sup- port the action of lead, but vanished entirely, leaving no signs of any metallic substance upon the cupel ; this shews the little pro- bability of converting mercury into gold or silver by the action of a violent fire. In the following year he presented a memoir to the Royal Academy of Sciences, at Paris, upon the same subject. We there learn, that mercury, kept in digestion for fifteen years, with a constant heat of 100°, was not fixed, nor any how changed, ex. cept that a little black powder (which by simple grinding in a mortar became running mercury) was found floating upon its sur- face. Hence is inferred, the impossibility of mercury's being changed in the bowels of the earth into any other metal, the heat in mines scarcely ever amounting to 100°. Though it might be impossible to change mercury into a metal, yet the philosophers by fire contended, that mercury, united to a particular kind of sul- phur, entered into the composition of all metals, and might by art be extracted from them ; lead was of all others thought the most likely, and the experiment had been reported to succeed by Van Helmont, and others ; but Boerhaave is positive, that nothing can be expected from its combination with salts, and lead, or tin. It was still thought by the alchemists, that mercury could never be freed from its original impurity, but by being joined to some pure body of the same nature with itself : this they thought gold and silver to be. Boerhaave, in order fully to subvert their high pre- tensions, gave in, to the Royal Society, another paper, in the latter end of the year 1736, containing an account of the unchangeable- ness both of mercury and gold, how often soever they were dis. tilled together. He repeated the distillation of mercury from gold above 850 times ; the mercury was not in any respect changed ; its specific gravity was the same as at first^ nor had it lost the pro- perty of being converted into a red powder by a due degree of TINNING, PLATING, &C. S21 heat. These were all the tracts which were published during th« life-time of Boerhaate ; he died in S ptembnr, 1738, and IP t Ins papers to his two brothers, and after their deaths th'-y fell into the hands of Charles Frederic Krusr, physician to the Empress of Russia; this gentleman hath published a short extract from Boer- haave's Diary, and promise's a fuller account of still more labo. • rious operations. We learn from this extract*, that Boerhaave had distilled the same mercury 1. '09 times, and its specific gravity was to that of water, as 13 ^£3 to I ; whilst that which had been but once distilled was as 13 TVo t-> 1 ; a difference which may ea- sily b< attributed to the different temperatures of the air when the experiments were made, or to other accidental circumstances, which the accuracy of Gravesande, with whom he made the expe- rim( nt, could not provide against. The mixture of quicksilver with gold, or silver, or lead, or tin, or copper, or any metallic substance with which it is capable of uniting, is called an amalgam ; and the operation by which the union is effected, is called amalgamation. Authors are not agreed as to the derivation of the word amalgam; some think that it is composed of two Greek words, (aaa ya^eiv), by which the inti- mate union, or marriage, as it were, of the two metals is denoted ; others are of opinion, that it ought to be written a malagma, and that it is derived from a Greek word (jH,aAa iliu work- men say, is quickened : a plate of glass is then cautiously slid « Novi Cummm. Pctrop. torn. ix. VOt. TI. Y TINNING, PLATING, &C. upon tho (in leaf, in such a manner as (o sweep off the redundant quicksilver, which is not incorporated with tin- tin ; leaden weight-) are then placed on the «lass ; and in a little time the quicksilvered tin-foil adheres so firmly to the glass, that the weights may be re« moved without any danger of its falling off. The glass thus sil- vered is a common looking.glass. About two ounces of quicksilver are sufficient for covering three square feet of glass. It is generally believed, that the art of making looking-glasses, by applying to their back surface a metallic covering, is a very modern invention. Muratori expressly says, that glass specula, such he means as are now in use, are not of. any great antiquity.— Serx autem antiquitati novimus fuisse specula^ quorum usus nun. quam desiit ; sed eorum fabricam apud I talus unice forsan Veneti per tempora multa servarunt et adhuc servant : qua: tamen alio translata nunc in aliis quoque regnis floret*. — The authors of the French Encyclopedic + have adopted the same opinion, ami quoted a Memoir, printed in the twenty-third volume of the Academy of Inscriptions, &c.— II est d'autant plus etonnant que les anciens n'aient pas connu I'art de rendre le verre propre a conserver la re- presentation des objets, en appliquant I'etain derriere les glaces, que les progres de la decouverte du verre furent, chez eux, pousses fort loin. — Mr. Nixon, in speaking of the glass specula of the ancients, says, " before the application of quicksilver, in the con. struction of these glasses, (which I presume is of no great anti- qaity), the reflection of images by such specula must have been effected by their being besmeared behind, or tinged through with some dark colour, especially black J." I have bestowed more time in searching out the age in which the applying a metallic covering to one side of a looking.glass was introduced, than the subject, in the estimation of many, will seem to deserve; and, indeed, more than it deserved in my own estimation : but the difficile* nugce, the stultus labor ineptiarum, when once the mind gets entangled with them, cannot be easily abandoned : one feels, moreover, a singular reluctance in giving up an unsuccessful pursuit. The reader would pardon the introduction of this reflection, if he knew how many musty volumes 1 turned over, before I could meet with any information which could satisfy me, in any degree, on this sub- » Mumtori Anliq. vol. ii. p. 39'. f Art. Miroir. t Phil. Trans. 1758. p. 60s?. TINNING, PLATING, &C. 321 ject ; T am not yet quite satisfied ; though I take the liberty to say, in opposition to Muratori, and the other respectable authorities which I have quoted, that the applying a metallic covering to look, ing. glasses is not a modern invention ; it is probable it was known in the first century, if not sooner; and it is certain, I apprehend, that it was known in the second. The Romans, before the time of the younger Pliny, not only used <;lass, instead of gold and silver, for drinking vessels, but they knew how to glaze their windows with it, and they fixed it in the walls of their rooms to render their apartments more pleasant. Now a piece of flat glass, fixed in the side of a room, is a sort of looking-glass, and if the stucco into which it is fixed be of a dark colour, it will not be a very bad one. And hence I think the Romans could not fail of having a sort of glass specula in use : but this, though admitted, does not come up to the point ; the questidh is, whether they covered the posterior surface of the glass with a metallic plate? It has been observed before, that the Ro- mans knew how to make a paste of gold and quicksilver ; and it appears from Pliny also, that they knew how to beat gold into thiu leaves, and to apply it in that state both on wood and metal : now there is a passage in Pliny, from whence it may be collected, that the Romans began in his time to apply a coat of metal to glass specula, and that this coat was of gold. The passage occurs in the very place where Pliny professes to finish all he had to observe concerning specula*. An opinion, says he, has lately been enter- tained, that the application of gold to the back part of a speculum, renders the image better defined. It is hardly possible that any one should be of opinion, that a plate of gold put behind a metallic speculum, could have any effect in improving the reflected image; but supposing Pliny (whose transitions in writing are often abrupt) to have passed from the mention of metallic to that of glass specula, then the propriety of the observation relative to tbe improved state of the image is very obvious. If we suppose the Romans, in Pliny's age, to have simply applied some black substance to the back surface of the glass, or even to have known huw to put tin behind it, yet the observation of the image being rendered more * Atque ut omnia do -pe-culis prra^ inlur hoc loco — Optima upud majorei fuerant BrunJn^na stanno ct acre mixta. PraelaU sum argcntca. Primus fecit Praxiteles, niagni Pompeii state. Nuper credi coeptum certiorem ima- gine-in reddi auro apposito avenU. .Hist. Nat. 1. xuiii. *. ilv. Y2 TINNING, PLATING, &C. distinct by means of gold, might have been made with more ju than is neiuTdlly supposed; for Burton is of opinion, that a look. 1114. glass made with a covering of gold and quicksilver, would re. ile;t more light than one made in the ordinary way with tin and quicksilver*; and hence Pliny's expression, certiorcm imaginetn reddi auto apposito aversis, will be accurately true. Alexander Aphrodiseus flourished towards the end of the second century; he wrote several works in Greek, and among the rest two books of Problems ; one of his problems is this + : A*a TI roc, Why are glass specula so very resplendent? The only part of the answer which we are concerned with, is, Because they besmear the inside of them with tin. The Greek word which I have here rendered besmear, does not clearly point out the manner in which the operation of fixing the tin upon the glass was performed. Pliny uses a Latin word (illitum) of exactly the same import as this Greek one, when he speaks of copper vessels being tinned ; and as in that operation, tin is melted and spread over the surface of the copper, I see no difficulty in supposing, that the tin may have been, in the time of Alexander Aphrodiseus, melted and spread over the surface of the glass, wh< n previously heated. Having carried up the invention of covering glass specula with a metallic coating to the second century, we may be the more ready to adnr.it that the Sydonians possessed this art, before Pliny wrote Ms Natural History : for in that work he not only praises them for their former iii£< -n'lity in various glass manufactures, but he adds — and they had iim-ntid specula alsoj. — Now there is some reason * Oo p r.irroit trouver le moyen de fairr tin inoillcur etamage, et je rrois qu'on parvlcndroit en employant de 1'or et du vifargent. — Hist. Nat. Bnffon. Sup. torn. i. p. 451. •T AAE3ANAPOT AtPOAlZEftS isrpixa awopn/uar* xai yle, who assures us that mercury has been sevrral titnes found in the heads of artificers exposed to its fumes*. In the Philoso- phical Transactions +, then- is an account of a man, who having ceased working in quicksilver for six months, had his body still 1-0 impregnated with it, that by putting a piece of copper into his mouth, or rubbing it with his hands, it instantly acquired a silver colour. This, though a surprising, is not a fact of a singular na. ture ; it is well known that sulphur, taken inwardly, will blacken silver which is carried in the pocket ; and 1 have somewhere read of a man whose keys were rusted in his pocket ; from his having taken, for a long time, large quantities of diluted acid of vitriol. 1 remember having seen, at Birmingham, a very stout man ren. dered paralytic in the space of six months, by being employed in fixing an amalgam of gold and quicksilver on copper ; he stood before the mouth of a small oven strongly heated; the mercury was converted into vapour, and that vapour was inhaled by him. A kind of chimney, I believe, has of late been opfn^d at the farther side of the oven, into which the mercurial vapour is driven, and the health of the operator is attended to. The person I saw was very sensible of the cause of his disorder, but had not courage to •withstand the temptation of high wages, which enabled him to con- tinue in a state of intoxication for three days in the week, instead of, what is the usual practice, two. [Bishop Watson. CHAP. VI. METALLIC PLANTS, OR TREES. BEFORE we quit the very curious and interesting subject of metals, we may observe that many of these substances when minutely dis- solved in a menstruum, and treated with a third substance that se- parates them wholly or in part from the fluid in which they are thus contained, crystallize into the appearances of very beautiful * Boy1e\ Works, vol. iii. p. 330. t 1665. LEAD TREK. 327 trees or plants, which are still usually known by the Latin name of arbors ; as the arbor Diance, or SILVER-TREE ; arbor Marti$, or IRON-TREE ; and arbor Plurnbi, or LEAD.TREE. These expe- riments are simple as well as curious and entertaining, and we shall, therefore, subjoin the following as the easiest processes for working them. Silver Tree. — Arbor Diana'. In this experiment the branches and figure of a tree are repre- sented by an amalgam of silver and mercury, which appear to vege- tate in a very beautiful manner. To obtain it, one part of silver, dissolved in nitrous acid to saturation, is mixed with twenty parts of clean water, and poured upon two parts of mercury. When left standing quietly, the desired crystallization will take place after some time. A cylindrical glass vessel is best suited for the purpose ; and that the process may succeed, it is necessary that the ingredients be in their utmost purity. Iron Tree. — Arbor Mortis. An apparent vegetation of iron, resembling a natural plant. It is formed by dissolving iron tilings in diluted nitric acid, and adding to the solution a quantity of carbonate of potash in a deliquescent state, or what was formerly called oil of tartar per deliquium. The mixture swells considerably, and is no sooner at rest than the branches spring out on the surface of the glass. Lead Tree. — Arlor Plumbi. Is a beautiful vegetation of lead. To form it, two drams of ace- tite of lead (sugar of lead) are dissolved in six ounces of distilled \vater ; the filtered solution is poured into a cylindrical glass, and a thin roll of zinc being hung in it, the whole is left standing at rest. The lead precipitates, adhering to the zinc in metallic leaves, in the form of a tree. [Editor. Y4 THE GALLERY OF NATURE AND ART. PART II. ART. BOOK IV. POLITE ARTS, or those connected with LITERATURE. CHAP. I. PAPER MAKING. IAPER is well known to be a thin flexible leaf, usually white, ar- tificially prepared of some vegetable substance, cliiefly to write upon with ink. The word is formed from the Greek •ma.itvpQs, papyrus, the name of an Egyptian plant, called also /3i?Ao;, biblus, whereon the ancients used to write. Various are the materials, on which mankind in different ages and countries hare contrived to write their sentiments ; as on stones, bricks, the leaves of herbs and trees, and tht ir rinds or barks ; also on tables of wood, wax, and ivory ; to which may be added plates of lead, linen rolls, &c. At length the Egyptian pa. pyrus was invented ; then parchment, then cotton paper, and lastly, the common, or linen paper. PAPEtt MAKING. 329 In some places and ages they hav«» even written on the skins of fishes; in others, on (he intestines ot se pents ; and in others, on the backs of tortoise". Mabill. de Re Diplotn. lib. i. cap. 8. Fa- bric. Biblioth. Nat. cap. 21, &c. There are few sorts of plants but have at some time been used for paper and books : and hence the several terms, biblos, codfi, libfT, fo'ium, tabula, tillura, philura, scheda, &c. whirh express the s< veral parts on which they were written : and though in Kurope ail these disappeared upon the introduction of the papyrus Hnd parchment, yet in some other countries the use of divers of them obtains to this day. In Ceylon, for instance, they write on the leaves of the talipot. And the Bramin MSS. in the Tulinga language, sent to Oxford from Fort St. George, are written on leaves of the ampana, or palma Malaba. rica : Hermannusgiv die Ktryptian paper, which was sometimes further polished by rubbing it w>tha glass ball, or the like. Uurk paper was only the inner whitish rind, inclosed between the bark and the wood of several trees, as the maple, plane, beech, and elm, but especially the tilia, or linden-tree, which was that mostly used for this purpose. On this, stripped off, Hatted, and dried, the ancients wrote books, several of which are said to be still extant. Chinese paper is of various kinds; some is made of the rinds or barks of trees, especially the mulberry-tree and elm, but chiefly of the bamboo and cotton-tree. In fact, almost each province has its several paper. The preparations of paper made of the barks of trees may be instanced in that of the bamboo, which is a tree of the cane or reed kind. The second skin of the bark, which is soft and white, is ordinarily made use of for paper: this is beat in fair water to a pulp, which they take up in large moulds, so that some sheets are above twelve feet in length : they are completed by dipping them, sheet by sheet, in alura water, which serves instead of the size among us, and not only hinders the paper from imbibing the ink, but makes it look as if varnished over. The paper is white, soft, and close, without the least roughness, though it cracks more easily than European paper; is very subject to be eaten by the worms, And its thinness makes it liable to be soon worn out. Cotton paper is a sort of paper which lias been in use upwards of six hundred years. In the grand library at Paris are manu- scripts on this paper, which appear to be of the tenth century ; and from the twelfth century, cotton manuscripts are more frequent than parchment cnes. Cotton paper is still made in the East In. dies, by beating cotton rags to a pulp. Linen or European paper appears to have been first introduced among us towards the beginning of the fourteenth century, but by whom this valuable commodity was invented is not known. Toe method of making paper of linen or hempen rags is as follows. The first instrument is called the duster, made in the form of a cylinder, four feet in diameter, and five feet in length. It is alto- PAPER MAKING. 331 gtther covered with a wire net, and put in motion by its connexion with some part of the mat hinrry. A convenient quantity of rags before the selection are inclosed in the duster, and the rapidity of its motion stparntes the dust from them, and forces it through the wire. It is ol considerable advantage to use the duster before se. lection, as it mak< s that operation les-> pernicious to the selectors. Tne selection is then to be made ; and it is found more conve- nient to hare the tables for cutting off the knots and stitching, and for forming them into a proper shape, in the same place with the cutting-table. The surface , both of these and of the cutting-table, is coti.posed of a w:re ner, which in every part of the operation allows the remaining part and refuse of every kind to escape. The rags, without any kind of putrefaction, are again carried from the cutting. table back to the duster, and from thence to an engine, where, in general, they are in the space of six hours re. duced to the stuff proper for making paper. The hard and soft of the same quality are placed in different lots; but they can be re. duced (o siuif at the same time, provided the soft is put somewhat later into the engine. The engine is that part of the mill which performs the whole action ol reducing the rags to paste, or, as it may be termed, of trituralion. The number of engines depends on the extent of the paper-work, or the force of water, or on the construction of the machinery. When the stuff is brought to perfection, it is conveyed into a genera) repository, which supplies the vat from which the sheets of paper are formed. This vat is made of wood; and generally about five feet in diameter, and two and a half in depth. It is kept in temperature by means of a grate introduced by a hole, and sur- rounded on the inside of the vat with a case of copper. For fuel to this grate, charcoal or wood is used ; and frequently, to pre. vent smoke, the wall of the building comes in contact with one part of the vat, and the fire has no communication with the place where they make tne paper. Every vat is furnished on the upper part with planks closed in- wards, and even railed in with wood, to prevent any of the stuff from running over in the operation. Across the vat is a plank, which they call the trepan, pierced with holes at one of the extre- mities, and resting on the planks which surround the vat. The forms or moulds are composed of wire cloth, and moveable 332 PAPER MAKING. frame. It is with these that they fetch up the stuff from the vat, in order to form the sheets of paper. The sides of the form are made of oak, which is previously steeped in water, and otherwise pre- pared to prevent warping. The wire cloth is made larger than the sheet of paper, and the excess of it on all sides is covered with a moveable frame. This frame is necessary to retain the stuff of which the paper is made on the cloth ; and it must be exactly adapted to the form, otherwise the edges of the paper will be rag- ged and badly finished. The wire cloth of the form is varied in proportion to the fineness of the paper and the nature of the stuff. The felts are pieces of woollen cloth spread over every sheet of paper, and upon which the sheets are laid to detach them from the adjoining, to prevent them from adhering together, to imbibe part of the water with which the stuff is charged, and to carry off the whole of it when pressed under the action of the press. The two sides of the felt are differently raised : that of which the hair is longest is applied to the sheets which are laid down ; and any alteration of this disposition would produce a change in the texture of the paper. The stuff of which the felts are made should be sufficiently strong, in order that it may be stretched exactly on the sheets without forming into folds ; and, at the same time, sufficiently pliant to yield in every direction without injury to the wet paper. As the felts have to resist the reiterated efforts of the press, it appears ne. cessary that the warp be very strong, of combed wool, and well twisted. On the other hand, as they have to imbibe a certain quantity of water, and to return it, it is necessary that the woof ba of cariled wool, and drawn out into a slack thread. These are the utensils, together with the press, which are used in the apartment where the sheets of paper are formed. „ The vat being furnished with a sufficient quantity of stuff and of water, two instruments are employed to mix them ; the one of which is a simple pole, and the other a pole armed with a piece of board, rounded and full of holes. This operation is repeated as often as the stuff falls to the bottom. In the principal writing, mills in England, they use for this purpose what is called a hog ; which is a machine within the vat, that, by means of a small wheel on the outside is made to turn constantly round, and keep the stuff in perpetual motion. When the stuff and water are prop« rly mixed, it is easy to perceive whether the previous operations have been complete. W hen the stuff floats close, and in regular flakes, it is PAPER MAKING. 333 » proof that it has been well triturated ; and the parts of the ragi which have ocnped the ro!K rs also appear. After tliis operation the workman takes one of the forms, fur- nished with its Crime, by the middle of the short sides; and fixing the frame round the wire cloth with his thumbs, he plunges it ob- liquely four or five inches into the Tat, beginning by the long side, which is nearest to him. After the immersion he raises it to a level : by these movements he fetches up on the form a sufficient quantity of stuff; and as soon as the form is raised, the water escapes through the wire cloth, and the superfluity of the stuff over the sides of the frame. The fibrous parts of the stuff arrange them- selves regularly on the wire cloth of the form, not only in propor- tion as the water escapes, but also as the workman favours this effect by gently shaking the form. Afterwards, having placed the form on a piece of board, the workman takes off the frame or deckle, and glides this form towards the coucher ; who, having previously laid his felt, places it with his left hand in an inclined situation, on a plank fixed on the edge of the vat, and full of holes. During this operation the workman applies his frame, and begins a second sheet. The coucher seizes this instant, takes M'ith his left hand the form, now sufficiently dry, and, having laid the sheet of paper upon the felt, returns the form by gliding it along the trepan of the vat. They proceed in this manner, laying alternately a sheet and a felt, till they have made six quires of paper, which is called a post: and this they do with such swiftness, that, in many sorts of paper, two men make upwards of twenty posts in a day. When the last sheet of the post is covered with the Jast felt, the workmen about the vat unite together, and submit the whole heap to the action of the press. They begin at first to press it with a middling lever, and afterwards with a lever about fifteen feet in length. After this operation, another person separates the sheets of paper from the felts, laying them in a heap ; and several of these heaps collected together are again put under the press. The stuff which forms a sheet of paper is received, as we have already said, on a form made of wire cloth, which is more or less fine in proportion to the stuff, and surrounded with a wooden frame, and supported in the middle by many cross bars of wood. In consequence of this construction, it is easy to perceive, that the sheet of paper will take and preserve the impressions of all the 354 PAPER MAKING. pieces which compose the form, and of the empty spaces between them. The traces of the wire cloth are evidently perceived on the side of the sheet which was attached to the for-e in this opnion. It seems however necessary for the pro- duction of voice, that a degree of tenseness should be communicated to the larynx, or at least to the two membranes above mentioned. The voice thus formed is strengthened and mellowed by a reverbe- ration from the palate, and other hollow places of the inside of the mouth and nostrils ; and as these are better or worse shaped for this reverberation, the voice is said to be more or less agreeable ; and thus the vocal organs of man appear to be, as it were, a species of iiiut or hautboy, whereof the membranous lips of the glottis are the mouth or reed, and the inside of the throat, palate and nostrils the body ; the windpipe being nothing more than the tube or canal which conveys (he wind from the lungs to the aperture of this musi- cal instrument *. The learned and ingenious author of Horniest, with great strength of argument, shews, that language is founded in compact, and not in nature. His friend, lord Monboddo, with great learn, ing and ingenuity, supports the same opinion, and insists that Ian. guage is not natural to man ; but that it is acquired : and, in the course of his reflections, he adduces the opinions not only of heathen philosophers, poets, and historians, but of Christian di- vines both ancient and modern ^. * See Dr. Beanie on the Theory of Language, p. 246, Loud. 1783, 4to. t See Hermes, by James Harris, Esq. book iii. p. 314, 327. J This author is of opinion that mankind took the hints of the most useful arts from the brule creation, " for," Eaith he, " it may be that men first learned to " build from the swallow ; from the spider, to weave ; and from the birds, to " sing." See Monboddo on the Origin aud Progress of Language, books i. and ii. p. 237 and 375. " The first words of men, like their first ideas," saith Mr. Harris, " had an " immediate reference to sensible objects ; and, in aftertimeg, when men began " to discover with their intellects, they took those words which they found al- " ready made, and transferred them, by metaphor,, to intellectual conceptions." Hermes, p. 269. 24 344 HIliKOiJLVI'lllC AND Thou;;?i language, as it is generally considered by grammarians, is a work of art ; yet it is evident li.ni vocal M> .m1 are founded in nature; nnd man would vary' those sounds, as impelled by his ; sions. or urged by his necessiti.-*. This t vrrise of the organs of uld produce articulate voices, which are peculiar to 'In- human species ; vocal sounds, expressive of «•. oti :;-•, being nataTfcl to brut- ^ as well as to men. These articulate voices are the first advances towards the formation of a language. The human 01 are not, like those of most brutes, confined to particular sounds ; but, as men are capable of learning to imitate the several sounds of the brute creation, by that means they acquire a greater variety of sounds than other animals. It is evident that children learn to speak by imitation ; they acquire articulate sounds before they comprehend the ideas of which those sounds are significa It would be digressing from the subject immediately before us, to say more at present concerning the nature of speech, or audible language ; our inquiry being into the origin of visible or written language. It is obvious that men would soon discover the difficulty of con. veying new ideas by sounds alone ; for, as Mr. Harris observes*, <{ the senses never exceed their natural limits ; the eye perceives •' no sounds, the ear perceives no figures nor colours;" therefore it became necessary to call in the assistance of the eye where the ear alone was insufficient. It will presently be demonstrated that men, even in their most uncivilized state, display a faculty of imitation +, which enables them to delineate objects and communicate information by rude pictures or representations. — For example, a man who had seen a strange animal, plant, or any other new object, for which he wanted a name, would have been almost mechanically led to illustrate his description by signs; and, if they were not readily comprehended, by a rude delineation in the sand, on the bark of a tree, on a slate, on a bone, or on such materials as first presented themselves : these being hanued about, naturally suggested the hint of using this me- thod of ronvejint; intelligence to a distant friend. The exercise of this uculty of imitation, so eminently conspicuous in the human species, will be found, on an accurate investigation, to have been * Hermes, p. 33J. t ArL-to.lc ^:i>s, man is the most imitative of all animals. •PICTURE WRITING. 345 common to all nations, and perhaps coeval with the first societies or communities of mankind. It is not probable that th<- art of picture, writing was brought to any dcqree of perfection by one man or nation, or even by one genera, tion ; but was gradually improved and extended, by t!ie successive hands of individuals, in the societies through which it passed ; and that more or less, according to the genius of each pi o,jle, and their state of civilization ; t!>e ruder nations requiring frwer si^ns cr representations, than the more cultivated. At first, each figure meant specifically what it represented. Thus, the figure of the sun expressed or denoted that planet only ; a lion or a dog, simply the animals there depicted : but. in process of time, when men acquired more knowledge, and attempted to describe qualities, as well as sensible objects, these delineations were more figuratively ex- plained ; then the figure of the sun, besides its original meaning, denoted dory and genial warmth ; that of the lion, courage ; and that of the do,>, fidelity. A still further improvement in civilization occasioned these deli, notations to become too volumnions ; every new object requiring a new picture, this induced the delineator to abridge the representa- tions, retaining so much of each figure as would express its species. Thus, for example, instead of an accurate representation of a lion, a slight sketch, or more general figure of that animal was sub- stituted ; and for a serpent, either a spiral or crooked line like the letter S. Besides this, as there occurred a number of ideas, not to be represented by painting, for these it was necessary to affix arbitrary signs. This transition was not so great as at first it may appear. In all probability, these signs were introduced slowly, and by degrees, and in such manner, as to be always explained by the context, until generally known and adopted. That such was the origin an I progress of this invention, history, and the journals of travellers, furnish us \\ith a variety of proofs ; hieroglyphics, in ail tin ir different stages being found in very distant parts of the globe. Of these we shall mention some in. stances. Joseph d'Acosta relates, that on the first arrival of the Spanish squadron on the coa>t of Mexico, expresses were sent to Monte- /.uina, with exact representations of the ships, painted on cloth ; in which manner they kept their records, histories, and calendars ; 346 ON HIEROGLYPHIC AND representing things that had bodily shapes, in their proper figures ; and those that had none, in arbitrary significant characters. — It is here to be observed, that the Mexicans had long been a civilized people ; so that this kind of writing may be considered among them as almost advanced to its most perfect state. Specimens of Mexican painting have been given by Purchas in sixty. six plates. His work is divided into three parts. The first contains the history of the Mexican empire, under its ten monarchs ; the second is a tribute-roll, representing what each conquered town paid into the royal treasury ; and the third is a code of their insti- tutions, civil, political, and military *. Another Tpecimen cf Mexican painting has been published, in thirty. two plates, by the present archbishop of Toledo. To all these is annexed a full ex- planation of what the figures were intended to represent ; which was obtained by the Spaniards from Indians well acquainted with their own arts. The stile of painting in all these is the same ; and they may be justly considered as the most curious monuments of art, brought from the new world t. * The originals arc in the Bodleian library at Oxford, No. 3134, among Mr. Sclden's MSS. In the same library, No. 2858, is a book of Mexican hierogly- phics painted upon thick skins, which are covered with a chalky composition, and folded in eleven folds. No. 3135, is a book of Mexican hieroglyphics painted upon similar skin?, and folded in ten folds. No. 3207, is a roll contain- ing Mexican hieroglyphics, painted on hark. These paintings are highly worthy the attention of the curious. •(• Upon an attentive inspection of the plates above mentioned, we may ob- serve some approach to the plain or simple hieroglyphic, where some principal part or.circumstance of the subject, is made to stand for the whole. In the an- nals published by Purchas, the towns conquered by each monarch are uniformly represented in the same manner, by the rude delineation of a house; but, in order to point out the particular towns, which submitted to their victorious arms, peculiar emblems, sometimes natural objects, and sometimes artificial figure* are employed. In the Tribute-roll, published by the archbishop of Toledo, the bouse, which was properly the picture of the town, is omitted ; and the emblem alone is employed to represent it. The Mexicans seem even to have made some advances beyond this, towards the use of the more figurative and fanciful hiero- glyphic. In order to describe a monarch who had enlarged his dominions by force of arms, they painted a target, ornamented with darts, and placed It be- tween him and those towns which he had subdued. But it is enly in one in- •tance, the notation of numbers, that we discern any attempt to exhibit ideas which had no corporeal form. The Mexicans had invented artificial marks, or signs of delineation, for this purpose : by means of these they computed the years of their king's reigns, ai well at the amount of tribute to be paid into the PICTURE-WRITING. 347 Charlevoix and several other travellers testify, that this kind of writing, or rather painting, was used by the North American In. dians, to record their past events, and to communicate their thoughts to their distant friends. The same kind of character! were found by Strahh nberg upon the rocks in Siberia ; and the author of the book, intitled, De vet. Lit. IJun. Scyth. p. 15, mentions certain innkeepers in Hungary, who used hieroglyphic reprcsenta. tions, not only to keep their accounts, but to describe their debt, ors : so that if one was a soldier, they drew a rude kind of sword ; for a smith or carpenter, a hammer or an axe ; and, if a carter, a whip. See Histoire Generate des Voyages, Paris, 1754. 4lo. The inhabitants of thf Friendly Islands, visited by Captain Cook, in 1779, made a great number of rude figures, to represent their deities. Captain King, who accompanied Captain Cook on his last expedition, brought from oneof these islands a piece of cloth, made of bark, on which several rude representations, of men, birds, and ornaments of dress, are depicted. Besides these, there are some delineations, which have the appearance of arbitrary marks. This cloth is divided into twenty. three compartments ; in one of which, near the centre, is a rude figure, larger than the rest, per- haps of some deity, having a bird standing upon each hand : that on the right hand appears to be addressing itself to his ear. This figure is surrounded by three smaller ones, which may be intended as ministers or attendants. The great figure is much in the stile of the Mexican hieroglyphic paintings at Oxford*. The Egyptians undoubtedly carried this art to its greatest ex. tent ; and this is one reason why they have been generally con. royal treasury : the figure of a circle represented a unit ; and, in small numbers, the computation was made by repeating: it. Larger numbers w ere expressed by peculiar marks ; and they had such as denoted all integral numbers, from twenty to eight thousand. The short duration of their empire prevented the Mexicans from advancing farther in that long course, which conducts men, from the la- bour of delineating real objects, to the simplicity and ease of alphabetic writing. Their records, notwithstanding some dawn of such ideas as might have led to a more perfect stile, can be considered as nothing more tlmn a species of picture- writine, so far improved, as to mark their superiority over the savage tribes of North America ; but still so defective, as to prove that they had not proceeded far beyond the first stage, in that progress which must be completed, before any people can be ranked among polished nations. See Dr. Robertson's Hint, of America, vol. ii. p. 286, and note 54, p. 47? — 182. • This cloth is now in my possession. 34S HII.K;.i;LYMIIC AM) sidered as the inventors of it ; every species of hieroglyphics being recorded in their history. Hieroglyphic writing, strictly so called, is a simple representa- tion, or mere picture. The abridgments afterwards introduced may be divided into three kinds. First, when the principal circumstance was made to represent the whole. In order to signify a battle, two hands were delineated ; one holding a bow, another a shield : a tumult, or popular insur- rection, was expressed by an armed man casting arrows ; and a siege, by a scaling-ladder. This may be stiled a picture character ; or, as the learned Dr. Warburton, bishop of Gloucester, called it, *' a Curiologic Hieroglyphic." The second, and more artificial method of contraction, was by putting the instrument fer the thing itself. Thus, an eye in the clouds, or eminently placed, was designed to . represent God's omniscience, as perceiving all things ; an eye and sceptre, to re. present a king ; and a ship and pilot, the Governor of the universe. This may be called the Tropical Hieroglyphic. The third, and still more artificial method of abridging picture- ivriting, was, by conversion, or making one thing stand for, or re. present another ; for example, the Bull Apis stood for Osiris, and not the picture or image of Osiris *. This hath been denominated the Symbolic Hieroglyphic +. * S une authors have said, that, at first, symbols had some quaint resemblance of, or analogy to, what they represented. Thus, among the Egyptians, a cat stood for the moon ; becavise the Egyptians held, that the pupil of her eye was enlarged at the full moon, and was contracted and diminished during its de- crease : a serpent represented the divine nature, on account of its great vigour and spirit, ils long ajc and revirescence. •f- That these improvements are not imaginary, is proved from a fragment of Sanchonialho, preserved by Euscbius, recording, " That Tuautus, having imi- " tated Ouranub's art of picture-writing, drew the portraits of the gods Cronus, mg, he yet remained stationed. "To each of the other gods he gave two wings on their shoulders ; as the "satellites, of Cronus, in his excursions; who had likewise two wings on hit " head, to denote the two principles of the mind, reason and passion." — Here we see that Ouranus practised a kind of picture-writing, which Taautus after- wards improved. PICTURE WRITING. 349 This, and the enormous bulk of the picture volumes, produced a further change in writing ; the figures were totally rejected ; and, in their room, certain arbitrary marks were instituted, ex. pressing not only visible objects, but mental conceptions. These of necessity must be exceedingly numerous, as is the case in the Chinese writings, in which some authors have asserted, they could still trace out the remains of the picture character. The learned bishop of Gloucester, Dr. Warburton, in his Divine Legation of Moses*, observes, that all the barbarous nations upon earth, before the invention or introduction of letters, made use of hieroglyphics, or signs, to record their meaning. Such a general concurrence in the method of preserving events, could never be the effect of chance, imitation, or partial purposes ; but must needs be esteemed the uniform voice of nature, speaking to the first rude conceptions of mankind ; *' for," adds the learned prelate, " not only the Chinese of the east, the Mexicans of the west, and the Egyptians of the south, but the Scythians likewise of the north, as well as those intermediate inhabitants of the earth, the Indians, Phenicians, Ethiopians, Etruscans, &c. all used the same way of writing, by picture and hieroglyphic." We shall dismiss the present section, by endeavouring to im- press the minds of our readers with a distinction which will be found to be of great importance in the present inquiry ; namely, the difference between imitative characters and symbolic or arbitrary marks. " Every medium," says Mr. Harris, in his Hermes, p. 331, 332, " through which we exhibit any thing to another's contem- plation, is either derived from natural attributes, and then it is an Imitation ; or else from accidents quite arbitrary, and then Taautus, or Thoth, was (he Mercury, on which name and family all the inven- tions of the various kinds of writing, were very liberally bestowed ; that here mentioned as.the improvement of Taautus, being the very hieroglyphics above described ; and that as before practised by Ouranus, the same with the simple American paintings. Such then was (he ancient Egyptian hieroglyphic ; and this the second mode of invention for recording mens actions, not as hitherto thought a device of choice for socrrsy, but an expedient from necessity for general use. I u pro- cess of time, (heir symbols and delineation-, turning on the least obvious, or even perhaps on imaginary properties of the animal or thing represented, either to form or construe this, required no small degree of learning and iDgcuuifv. * Vol. iii. p. 97 to 305. 350 ORIGIN OF LETTERS, it is a Symbol." The former may be truly said to derive its origin from that imitative faculty which is so conspicuous in the human species ; tho latter is founded in necessity or convenience, and becomes significant by compact : the one hath only an imme- diate reference to sensible obji cts, which present themselves to the sight ; thp other to mental conceptions : in short, the fonver is ap- plicable to hieroglyphic representations; the latter comprf hnit: symbols and marks for sounds, significant of ideas by adoption. Hence we may conclude, that all representations, marks, or cha- racters, Which were ever used, by any nation or people, must hare been either imitative or symbolic*. [Astle. SECTION II. On the Origin of Letters, and the Invention of Alphabets. THE art of drawing ideas into vision, or of exhibiting the con- ception of the mind by legible characters, may justly be deemed the noblest and most beneficial invention of which human i unity can boast : an invention which hath contributed more than all others to the improvement of mankind. This subject has engaged the attention and perplext-cl tin- sagacity, of many able and judicious persons for more than two centuries : some of the most respectable writers have rca. soned upon erroneous principles, and, by their works, have ob- * Aiaip ipti Si TO OMOIiiMA T* ZTfMBOAOY, KtxQifn TO /ui» Susl^aa Tr.y «{>uriv CITJ-> Tu -T^ay/nare; xara TO JtvaTW a7rii^»vi^itf-9aj BaXnai, xat ax l;nv f$' iiu.~v iiri /.xirxTrXs'ra*.— T» >£ ys ' iifjiiv ij^ii, «TI x«< ix juiurr t«})i(Ta(u£V6» -rtt nptrefaz lirnitas' A representation or resemblance differs from a symbol in as much as (he re- semblance aims as far as possible) (o represent the very nature of the tiling, nor is it in our power to shift or vary it : but a symbol or sign, is wholly in our power, as depending singly for its existence on our imagination. Aminon. in lib. de Interp. p. 17, b. The above in the meaning to be annexed to the word symbol, the pri.-iripal u nid- being to explain things ; but the great Lord Baron truly obi-erM--., " That the first di.-temper of learning is, when men study words and :iolii'.;. Shaw's Baron, vol. i. p. S3. That excellent writer was SH> stronglv ini;., Vfith thiii sentiment, that he makes the same observation in different parts of hi* works. It i-, ^aid of IMutan -li. (Sat, like a true philosopher, he regarded things, more than word*. THE INVENTION OP ALPHABETS. 351 scured the true path which might have led to the discovery of let- ters. Monsieur Fourmont, Bishop Warhurton, and Monsieur Gebelin, have endeavoured to shew, that alphabets were originally made up of hieroglyphic characters ; but it will presently appear, that the letters of an alphabet were essentially different from the characteristic marks deduced from hieroglyphics, which last are marks for things and ideas, in the same manner as the ancient and modern characters of the Chinese ; whereas the former are only marks for sounds; and, though we should allow it an easy transi. tion, from the Egyptian hieroglyphics, td the characteristic marks of the Chinese, which have been demonstrated by Du Halde and others to be perfectly hieroglyphic, yet, it doth not follow, that the invention of an alphabet must naturally succeed these marks. It is true, there is a resemblance between the Mexican picture, writing, the Egyptian hieroglyphics, and the Chinese characters; but these are foreign to alphabetic letters, and, in reality, do not bear the least relation to them. The hieroglyphic characters of the Chinese, which are very nu- merous, are in their nature imitative, and do not combine into words, like arbitrary marks for sounds or letters, which are very few, and are of a symbolic nature. We shall shew, that these authors, whose learning and ingenuity entitle them to the highest respect, and whose writings have furnished many useful hints to. wards the discovery of alphabetic characters, have not filled up the great chasm between picture-writing and letters, which, though the most difficult, was the most necessary iking for them to have done, before they could attempt to account for the formation of an alphabet. We shall demonstrate, that letters do not derive their powers from their forms, and that originally their forms en- tirely depended on the fancy or will of those who made them *. — Other writers who have considered this difficult subject, have freely confessed that it was above their comprehension t. Many learned men have supposed that the alphabet was of di. vine origin ; and several writers have asserted, that letters were / * See Moiis. Founnont's Reflections Crit. sur les Hist, des Anc. Peuples, torn. ii. a Paris, 1735. — The Divine Legation 8f Moses, by the late Dr. Warbiir- ton, bishop of Gloucc-Mer, vol. iii. p. 121. MODS. Gebelin's Monde Primilif, vol. iii. Paris, 1775. t Mr. Wisp's Essay on the Origin of the Language and Letters of Europe, p. 92, 93. See Universal Historv, vol. xx. p. 18, n. M. 362 ORIGIN OF LETTERS, first communicated to Moses by God himself* ; whilst others have contended, (hat the Decalogue u as the first alphabetic writing. It is highly proper for us to inquire how far these opinions arc well founded ; for, if they can be supported, there is an end of our pursuit; but if it shall appear that they are warranted neither by reason nor by scripture, we shall be at full liberty to pursue our inquiry : for the satisfaction therefore of thpse who have adopted those opinions, it is incumbent on us to have recourse to the Holy Scriptures themselves. The first mention of writing recorded in Scripture, will be found in Exodus xvii. v. 14; " And the Lord said unto Moses, Write-r this, for a memorial, in a book ; and rehearse it in the ears of Jo- shua ; for 1 will utterly put out the remembrance of Amalek from under heaven." This command was given immediately after the defeat of the Amalekites near lloreb, and before the arrival of the Israelites at Mount Sinai. It is observable, that there is not the least hint to induce us to believe that writing was then newly invented ; on the contrary. we. may conclude, that Moses understood what was meant by writing in a book; otherwise God would have instructed him, as he had done Noah in building the ark J ; for he would not have been commanded to write in a book, if he had been ignorant of the art of writing; but Moses expressed no difficulty of comprehension, when he received this command. We also find that Moses wrote all the words and all the judgments of the Lord, contained in the twenty-first and the two following chapters of the book of Exodus, before the two written tables of stone were even so much as pro. mised§. The delivery of the tables is not mentioned till the * Of these opinions were St. Cyril, Clement of Alexandria, Eusebius, and Isidore of Seville, amongst the fathers; and Mr. Bryant, Mr. Costard, Mr. Windar, with many other?, among the moderns. See St. Cyril against Julian, book viii. ; Clement of Alex, book i. .-tromut. cap 23 ; Kuseb. Preparat. Evang. lib. ix. cap. 7 ; Isidore, Origin, lib. i. cap. 3 ; Mr. Bryant's Ancient Mytho logy; Mr. Costard's Letter to Mr. Halhcd ; and Mr. Windar's Essay on Know- ledge, p. 2.ch. i. Univ. Hist. vol. iii. p. 212, Note T. t The Hebrew word ana, which word i- generally used for drawing letter? or literal characters; to write; Kxod. xxiv. v. 4 ; and chap, xxxiv. v. 18. — See Parkhurst's Lexicon. • | Gen. \\. ver. 14,J5, 16. * ^ " And MOM | the word- (if the Ljpi, &c." F.xod. x*iv. v. 1. " And he took the book of the covenant, and read ii in the audience of (he people; and they said, AH that the Lord hath said we will do, and be obe- dient." Ibid. v. 7. AND THE INVENTION OF ALPHABETS. 33J eighteenth verse of the thirty-first chapter, after God had maJe an end of communing with him upon the mount*, though the ten commandments were promulgated immediately after his third de. scent. It is observable, that Moses no where mentions that the alphabet was, a new tiling in his time, much less that he was the inventor of it; on the contrary, he speaks of the art of writing as a thin.; well known, and in familiar use ; for, Exodus xxviii. T. 21, he says, u And the stones shall be with the names of the children of Israel, twelve ; according to their names, like the engravings of a signet, every one with his name, shall they be, according to the twelve tribes." And again, v. 36, u And thou shall make a plate of pure gold, and grave upon it, like the engravings of a signet, Holi. ness to the Lord." Can language be more expressive ? Would it not be too ab.-uril to deny that this sentence must have been in words and letters? But writing was known and practised by the people in general in the time of Moses, as appears from the following texts, Deut. chap. vi. v. 9; chap. xi. v. 20; chap. xvii. v. 18; chap. xxiv. v. 1 ; chap, xxvii. v. 3, 8. By this last text, the people are commanded to write the law on stones ; and it is observable, that some of the above texts, relate to transactions previous to the delivery of the law at Mount Sinai. If Moses had been the inventor of -the alphabet, or received let, ters from God, which till then had been unknown (o the Israelites, it would have been well worthy of his understanding, and very suitable to his character, to have explained to them the nature- and use of this invaluable art which God had communicated to him ; and may we not naturally suppose, that he would have said, when he directed the workmen to engrave names and sentences on stones and go(d t, *' And in these engravings you shall use the alphabetic* characters which God hath communicated to me, or which I have now invented, and taught you the use of?" But the truth is, he • The different times of Moses' ascending and descending (he Mount ar« distinguished n the following pas-ages. First a-cenl. Exod. xix. v. 3. Pint de*crn'. v. 7. Stcond af cent, Exod. xix. v. 8. S cond deirrnt. Kxod.xix. v. 14. Third asctnt. Exod. xix. v. 20. Third descent. Exod. xix. T. Fourth atcent. Exod. xxiv. v. IS. Fourth descent. Exod. xxnii. vi f See^more texts on ihisTubject in fJenenis, chap, xxviii. verses 9, 10, II j and chap, xxxix. v. 34 ; Dcut. chap, xxviii. v. 58 ai.d 61 ; and chap. xxi\ vor,. vi. 2 A ORIGIN OP LETTERS, refers tht>m to a model in familiar use, 7r^-. The same author, in his Phaedrus, makes the god Theuth or Mercury, the inventor of letters. Diodorus Siculus tells us, that Mercury invented the first characters of writing, and taught men the rudiments of astronomy t ; and Cicero, in his Tusc. Quest, lib. i. delivers his opinion upon this subject in the following words: *• Quid ilia vis, quae tandem est, qnae investigat occulta? aut qui sonos vocis, qui indniti videhantur, panels literarum notis terminavit? — Philosophia vero omnium mater artium, quid est aliud, nisi, ut Plato ait, donum, ut ego inventum Deorum ?" The same author, in his Natura Deorum, lib. Hi. says, that Hermes or the fifth Mercury, whom the Eg) ptians called Thoth, first commu- nicated letters to that people. The Gentoos affirm, that letters were communicated to their ancestors by the Supreme Being, whom they call Brahmah J. Although, from these authorities, we may infer that the art of writing is of great antiquity, yet they discover to us that the ancients had very imperfect ideas of its true origin ; for Plato says§, "that some, when they could not unravel a difficulty, brought down a god, as in a machine, to cut the knot :" and the Claraval, Monsieur du Pin, in his Universal Historical Library, p. 81, support! these authorities ; and adds, that there is an infinite number of ancient and mo- dern stones thus engraven, which were used forsiguets. That signets wero used by the Hebrews, before they went into E-jypt, we learn from Gen. chap, xxxviii. v. I Si, where it appears, that Jndah gave Tharaar his signet, &c. : and it is reasonable to suppose, that this signet was similar to those used by the Israelites, and the other neighbouring nations. • SeeTol ii. |>. 18; edit. Scrran. f Lib. i. sect 1. J See Mr. Halhed's preface to the Gen too Lawi- & Set the Cratylis edit. Fi»c. p.29|. 2 A 2 ORIGIN OF LKTTERS, learned bishop of Gloucester observes, that the ancient^ gave no. thing to the gods, of whos;1 original they had any records; bat where the memory of the invention was lost, as of seed corn, wine, writing, civil society, &c. the gods seized the property, by that kind of right which gives strays to the lord of the manor *. The holy scriptures having left this subject open to investigation, and the prophane writers having given us nothing satisfactory upon it, we are at liberty to pursue our inquiry into the origin of let- ters ; but, in order to qualify ourselves for this task, it may be proper to enter into a philosophical contemplation of the nature of letters, and of their powers, which will best enable us to discover the true origin of their invention. A little reflection will discover, that men, in their rude unculti- vated state, had neither leisure, inclination, nor inducement, to cultivate the powers of the mind to a degree sufficient for the for- mation of an alphabet ; but when a people arrived at such a state of civilization, as required them to represent the conceptions of the mind which had no corporeal forms, necessity, the mother of inven- tion, would occasion further exertions of the human faculties, and would urge such a people to find out a more expeditious manner of transacting their business, and of recording their events, than by picture-writing; for the impossibility of conveying a variety of intellectual and metaphysical ideas, and of representing sounds by the emblematic mode of writing, would naturally occur, and there- fore the necessity of seeking out some other that would be more comprehensive, would present itself. These exertions would take place whenever a nation began to improve in arts, manufactures, and commerce ; and the more ge- nius such a nation had, the more improvements would be made in the notation of their language, whilst those people who had made less progress in civilization and science, would have a less perfect system of elementary characters; or would for ages advance no further in this art, than the marks or characters of the Chinese !• Hence it results, that the business of princes, and the manufactures * Bishop \Varl)iirfoii's Divine Legation, vol. iii. p. 62. + If it should be asked, why the Chinese still adhere to the ancient mode of writing; it may be answered, that their adherence to aibitrary marks, formed, and -aill continues to form, a part of the civil and religious policy of their country ; in the same manner as the prohibition of printing, forms a part of the civil policy within the dominion, of the emperor of Constantinople. AND THE INVENTION OF ALPHABETS. 3,37 sad commerce of each country, produced the necessity of devising some expeditious manner of communicating information to their subjects, or commercial correspondents at a distance. Such an improvement was of the greatest use, not only to the sovereign and the statesman, but to the manufacturer and the mere! ant. We shall for the present, omit the mention of several modes of writing which were practised by different nations, in the course of their progress towards civilization, because such accounts would more properly come under the history of the writing of each coun. try ; particularly under (hat of Egypt, whose inhabitants displayed every species of writing in the course of their improvements. At present we shall pursue that part of our inquiry which relates to the formation of an alphabet. Let us then in this place just premise, that arbitrary marks are of dirterent kinds. First, those used by the Chinese ; many of which were originally picture.characters. Secondly, those used by the notarii amongst the ancients, and by the present short-hand writers ; and thirdly, marks for sounds j such as elementary cha- racters or letters, and musical notes. The marks of the first and second kind are very numerous, as will appear hereafter ; those of the third are very few, as will pre- sently be demonstrated. It sit ms obvious, that whilst the picture or hieroglyphic pre. sented itself to the sight, the writer's idea was confined to the figure or object itself; but when the picture was contracted into a mark, the sound annexed to the thing signified by such mark, would be. come familiar; and when the writer reflected, how small a number of sounds he made use of in speech to express all his ideas, it would occur, that a much fewer number of marks than he had been accustomed to use, would be sufficient for the notation of all the sounds which he could articulate. These coiisideiations would in- duce him to reflect on the nature and power of sounds; and it would occur, that, sounds being the matter of audible language, marks for them must be the elements of words. Aristotle justly observes, " that words are the marks of thoughts; and letters, of words." Words are sounds significant, and letters are marks for such sounds*. ^ The learned author of Hermes above quoted, informs ast, * See Lord Bacon's Works by Sliaw, vol. i. p. IS?, f Book iii. chap. 2- p. 334. 2 A 3 358 ORIGIN OF LETTERS, *' That to ibout twenty plain elementary sounds, we owe that va. riety of articulate voices which have been sufficient (o explain the sentiments of so innumerable a multitude, as all the present and past generations of men." As there are but a sm.ill number of marks for sounds, called notes in music, so there are but a small number of distinct articulate sounds in every language. In different languagts their number differs ; and there are but few sounr's in any two languages that are exactly the same; although by the great intercourse between the European nations, the sounds of different languages daily assimilate. Mr. Sheridan says, that the number of simple sounds in our tongue is twenty-eight*. Dr. Kcnrick says, we have eleven distinct species of articulate sounds, which even by contraction, prolongation, and composition, are increased only to the number of sixteen ; every syllable or articulate sound in our language, bei g one of this number -f. Bishop Wilkins, and Doctor William Holder, speak of about thirty-two or thirty-three distinct sounds. It has been said, that among the Greeks and Romans, their writ, ten alphabet exactly accorded to the several distinct sounds and modes of articulation in their languages ; so that each sound had its distinct mark, by which it was uniformly and invariably repre- sented. Ten simple marks or characters, have been found suffi- cient for all the purposes of numerical calculations, which extend to infinity. Seven notes comprise the whole of music : these, by their dif- ferent arrangements, produce thai variety of harmony which we so justly admire. If we would ascend higher than eight notes, we only begin another series of the same distances. — Again, the scale doth not admit of a division into equal parts : this must correspond with the laws of sound : as every piece of music is but these notes varied, it must ct.nje to a close in the lowrst note, or its octave. It is evident, ih-t, trom the confined natun- of the organs, the simple natural sounds to be distinct roust he fewj and though ar- tiftre or affectation may invent u greater variety, they n;ust be de- ficient in precision as they increase in n m,b«T. Indeed, there are several sounds proceeding from inanimate obj. cts ; as the murmur. * S - 'is Rhetorical Grammar, prefixed to his Dictionary, printed at London in I7*»". t See Dr. Kenrick's Rhetorical Grammar, prefixed to Irs Dictionary. AND THE INVENTION OP ALPHABETS. ing of a stream, &c. that are not adapted to the human organs of utterance. It would be digressing too far from our subject, to enter into a discussion concerning the number of sounds that are known to exist, nor is this necessary; for as sounds are few, the marks for them need not be many j but marks for things are very nume- rous. It is however requisite for our readers to distinguish betxveen vi. sible and audible language. This distinction is justly made by St. Augustine in the following words : " Signa sunt verba visibilia, verba signa audibilia." The articulate sounds of vocal or audible language are resolvable into sentences, words, and syllables ; and the analysis of language into elementary sounds, seems first to have led to the invention of symbols, or marks, for mental conceptions. This invention must have taken place much about the time that men began to reform the barbarous jargon they first spoke, and form a language ; for which purpose, the knowledge of elementary sounds and their powers, was absolutely necessary. The progress in this science, as has been already observed, must have been by degrees : men would begin no doubt, by distinguishing the sound of one word from that of another, — this would not be difficult ; then they would resolve words into syllables, which would not be so easy : but it is likely that they stopt there for a long time, perhaps for ages, be. fore they came to the last resolution of sjllables into the distinct sounds of which they are composed. This was a very extraor- dinary work of art, which could only be performed by those who had consideied the laws of sounds; and could not be the result of chance, as some speculaiists have imagined; for this was in fact, the decomposition of a language into the sounds of which it was composed. The next step towards the notation of language, would be the delineation of a separate mark or letter to di note or stand for each sound ; which marks though few in number, would admit of so great a variety of arrangements and combinations, as would be ca- pable of producing an infinity of articulate sounds, sufficient for the composition of syllables, words, and sentences ; and conse- quently for the notation of language. That able mathematician Tacquet informs us, that the various combinations of the twenty. four letters (without any repetition) 2 A4 StiO ORIGIN OF LETTEHS, will amount to 620,448,401, 733,239,439, 3«),000. Thus it is evident, (hat twenty. four letters will admit of an infinity of combi- nations and nnan-c rents, sulficient to reprneot not onl> all the conceptions of trie mind, but all words in ill languages whatever. It is easy to conceive the astonishment of the human mind, at the first discovery of the doctrine and powers of combinations, which immediately led to the composition of written language, by the assistance of a small number of marks or letters ; though the transferring of id^as by these means from the ear to the eye, was a very extraordinary etlbrt of the human mind ; yet if we suppose that the analysis of the sounds of language was already made, it was no more than finding out marks for what was known before : and we have already shewn, that symbols were in general use among mankind, before they knew the use of letters ; and there- fore the invention of the latter, was nothing more than the trans- ferring the former method of representation, to the elements of sound. If the notation of music had been invented before letters, vliich mLht have happened, the discovery would have been just as great as that of letters. As there are more sounds in some languages than in others, it follows of course that the number of elementary characters or let. ters, must vary in the alphabets of different languages. The He. brew, Samaritan, and Syriac alphabets, have twenty-two letters ; the Arabic twentv -ei_rht ; the Persic, the Egyptian or Coptic, th:rty- t*o ; the present Russian forty-one ; the Shanscrit fifty ; the Cash- niirinn and Malabaric are still more numerous. Mr. Sheridan observes, that our alphabet is ill calculated for the notation of the English tongue, as there are many sounds for which we have no letters or marks; and there ought to be nine more cha- racters or letters to make a complete alphabet, in wliich every simple sound ought to have a maik peculiir to itself. The reason of the deficiency is, that our ancestors adopted the Roman alpha, bet for the notation of our language, thounh it ^as b) no means suitt d to it. Every alphabet is to be considered as the elements of words, v'.'j-ver it may be received b> compact; for our roadi r- must not forget, that all words, as well as s> niboJs, letters, or elements of words, are significant onl) by habit or agreement. As vocal or audible langunge is resolvable into sentences, words, AND THE INVENTION OF ALPHABETS. 3Cl and syllables ; so written or visible language is composed of letters, syllables, words, and sentences. A letter is an urbi'r..;y mark, made to signify or stand for a par. ticuUr sound significant uy compact ; aud may be properly termed a mark for a certain known sound. A determinate or established number of these marks, constitutes the elements or alphabet of written language. The combinations and arrangements of these elements or letters, as settled by con- sent or compact, compose the written languages of civilized nations. Tne first step towards the composition of written language, is to conTey an idea of som^ ^ouiid ; « ithtr by a i-ingle mark or charac- ter, or by wr.ting two or more of them, which form a syllable : one or moqg of these syllables make a word which is a voice articulate, and significant !>y compact : a s.ent< nee is a compound quantity of sounds significant ; ot which cer;ain parts are themselves also sig- nificant : several words nrike a sentence, and several sentences a memoir or discourse. Writing then, may be defined by the art of exhibiting to the sight the conceptions of the mind, by means of marks or characters significant by compact of the sounds of language, which enable us to transfer ideas from the eye to the ear, and vice versa. Thus it has been shewn how ideas niay become the objects of vision, and be exhibited to the e)e in legible characters ; and that the notation of language maj be performed, by making a sufficient number of markt, lor sounds, and b\ arranging and combining them properly. The elements of all written language are divided into rowels and consonants 5 the former of which is defined to be a simple articu- late sound, uttered by a single impulse of the voice, and forming an articulate sound by itself ; whereas a consonant forms no arti- culate sound of itself, but only assists in forming a sound. The vowels were probably invented first, but the consonants form the body ot language, and are properly termed the bones and sinews th M of. The consonants are divided into mutes, and liquids, which will seldom join together in the same syllable ; nor will any two of the mutes associate in u syllable, eith'-r in English or in Latin. There are some exceptions as to the association of mutes. The first composition of written language, % of letters into syl- 3(52 ORIGIN OP LETTERS, &C. tables ; but it is observable, that all letters will not compound with all ; the vowels will not only mix with each other, or form diph- thongs; but they will compound in syllables with all the conso- nants so called, because they sound in company with the vowels. But this does not hold of the consonants with respect to one ano. ther; for only some of them sound together in syllables, whilst others cannot associate together in that way ; the reason of which is, that the configuration of the mouth, and the action of its or- gans, are so different in the pronunciation of some of (hem, that they cannot be joined together in the same enunciation, nor with* out some rest or pause betwixt; so that there must be time to give a different configuration and action to the organs ; whereas, when the pronunciation is not so different, the sounds may be so run to- gether, as to incorporate in one syllable ; and in this way, fire, or even six consonants, may be joined in the same syllable, as in the English word, strength. The next composition of articulate sounds, is of syllables into words ; and the better the composers of such words were ac. quainted with the nature and harmony of sounds, the more harmo- nious would be their written language. On the contrary, a defi. ciency in the knowledge of sounds, is a considerable obstruction to the discovery of what consonants will incorporate with each other ; and from this ignorance proceeds that redundancy and su- perfluity of letters, which is conspicuous in many languages. It is observable, that many of the consonants, which admit of a junction in the same syllabic, do not produce harmonious sounds. In truth, the manliness or effeminacy, the harmony or harshness, of a written language, will, in a great measure, depend on the proper or improper junction of letters in syllables. The proper arrange, ments and combinations of letters, constitute that branch of science called grammar, which consists of four parts ; namely, orthography, prosody, etymology, and syntax. Grammarians divide language into what they call parts of speech ; but they differ as to the number of the parts, of which speech is composed. Mr. Harris clearly shews, that all words whatever, are either substantives, definitives, attributives, or con. nectives; the substantives may be called nouns; the attributives, verbs ; the definitives, articles ; and the connectives conjunctions. As to the pronouns, adverbs, prepositions, and interjections, he w ANTTQUITY OP WRITING. 363 of opinion, that they must be found included within the specie! abovementioned. [Astle. SECTION III. Antiquity of Writing^ and the Claims of different Nations t« the Honour of its Invention. THE art of writing is of great antiquity, and the written annals of ancient nations are so imperfect or fabuK-us, that it will be ex. tremely difficult to decide to what nation or people the honour of the invention belongs; for, as Sir Isaac Newton justly observes, '* there is the utmost uncertainty in the chronology of ancient kingdoms, arising from the vanity of each in claiming the greatest antiquity, while those pretensions were favoured by their having no exact accounts of time. " It has already been observed, that letters were the produce of a certain degree of civilization among mankind ; and therefore it is most probable, that we shall obtain the best information, by having recourse to the history of those nations who appear to have been first civilized. EGYPTIANS. As a great number of authors have decided in favour of the Egyptians, who have an undoubted claim to an early civilization, we shall begin our inquiries with that people; and, as th* y dis- played every species of writing in the cour«e of their improve- ments, we shall pursue the thread of their history, which will reflect considerable li^ht on what has bpen already advanced. Dr. Warburton, bishop of Gloucester, atfirms, that the Egyp- tians were the first people who discovered the knowledge of the divine nature: and amongst tlie first who tan. tit (he im- mortality of the soul*. In anoO.er ulace he giv«-s to an account of the state of their learnii,^ and .superstitions in lie time of Moses. He contends, that Eg>pt »«s th« par«-i:i of all the teaming of Greece, and WHS resorted to by tlie Grecian Kgi- ators, naturalists, and philosophers. '1 he same prelate, with great erudition, and * Divine Legal, of Moats, TO), i. p. 165; vol. ii. p. 100 lu 105; vol. iii. p. 17 ; ibid. p. 25 to 39. W> are indebted to (his prelate for great part of what u here said of the Egyptians. 364 ANTIQUITY OF WRITING. strength of argument, endeavours to prove, that Egypt was pro. bably one of the first civilized countries on the globe. In order to give the reader a clear idea of the several kinds of Egyptian writing, it will be proper to observe, that this writing was of four kinds. The first, hieroglyphic ; the second, symbolic; the third, epistolic; and, the fourth, and last, hierogrammic. Porphyry *, speaking of Pythagoras, informs us, <; That he so. journed with the priests in Egypt, and learnt the wisdom and Ian. guage of the country, together with their three sorts of letters ; the epistolic, the hieroglyphic, and the symbolic j of which, the hieroglyphic expressed the moaning of the writer, by an imitation or picture of the thing intended to be expressed ; and the symbolic, by allegorical enigmas." Clemens Alexandrinus is larger and more explicit — " Now those who were instructed in the Egyptian wis- dom, learnt, first of all, the method of their several sorts of letters ; the first of which is called epislolic ; the second, sacerdotal, as being used by the sacred scribes; the last, with which they con. elude their instructions, hieroglyphical. Of these different me. thods, the one is in the plain and common way of writing by the first elements of words, or letters of an alphabet- the other, by symbols. Of the symbolic way of writing, which is of three kinds ; the first is, that plain and common one, of imitating the figure of the thing represented; the second is, by tropical marks; and the third, in a contrary way, of allegorizing by enigmas. Of the first sort, namely, by a plain and direct imitation of the figure, let this stand for an instance: — to signify the sun, they made a c'rcle ; the moon, a half circle. The second, or tropical way of writing, is by changing and transferring the object with justness and propriety : this they do sometimes by a simple change, sometimes by a complex multifarious transformation ; thus they have engraven on stone and pillars, the praises of their kings, un. der the cover of theologic fables. Of the third sort, by enigmas, take this example ; the oblique course of the stars, occasioned their representing them by the bodies of serpents; but the sun they likened to a scarabaeus, because (his insti t makes a round ball of beast's dung, and rolls it circularly, with its face opposed to that luminary." These two learned Greeks, though not quite correct in their do. * De Vita Pythag. cnp. xi. |t. 16. ANTIQUITY OF WRITING. 30. fiuitions of writing, prove, that the several kinds abovemcntioned were used by the Egyptians. Indeed, they reckon but three kinds of writing, when in fact, there were four. Porphyry names ouly three sorts, epistolic, hieroglyphic, and symbolic: and this was not much amiss; because the fourth, the hierogrammic or sacerdotal, not dif. fering from the epistolic in its nature, he comprised it under the general term of epistolic. — It is observable, that Porphyry judici. ously omits to explain epistolary writing, as supposing it to be well known : but Clement adds to epistolic the hierogrammic, which was alphabetic, but being confined to the use of the priests was not so well known : he with equal judgment explains the nature of these characters. The Egyptians, as hath been observed, in the most early ages, wrote like all other infant nations, by pictures ; of which rude orJ, ginal essays some traces are yet remaining amongst the hierogly. phics of Horapollo, who tells us, that the ancient Egyptians painted a man's two feet in water to signify a fuller ; and smoke ascending to denote fire*. Out to render this rude invention less incommo- dious, they soon devised the more artful and expeditious way of putting the principal part for the whole, or by putting one thing of resembling qualities for another. The former was the curiologic hieroglyphic ; the latter, the tropical hieroglyphic ; which last was a gradual improvement on the first, as appears both from the nature of the thing, and from the records of antiquity +. These alterations in the manner of delineating hieroglyphic figures, produced and perfected another character, which hath been called the running hand of hieroglyphics, resembling the Chinese writing, which having been first formed by the outlines of each figure J, became at length a kind of marks : the natural effects of which were, that the constant use of them, would take oft the at. tention from the symbol, and fix it on the thing signified ; by which means the study of symbolic writing would be much abbreviated, because the writer or decyphercr, would have then little to do, but • Lib. i. c.65; Lib. ii. c. 16. t Many instance!* of this kind may be found in Horapollo, lib. i. c. 14 and 40. Plutarch Is. and O-ir. Diod. Sic. lib. i. | The inquisitive reader, by comparing Kircher's Account of Egyptian Hie- roglyphics with those published by Purchag, will find that the former exactly re- tcmble the Mexican, nut only in their use, but, as Purcha* (p. 69) and Diodorus Siculus(p. 194) say, in their forms and figures. 366 ANTIQUITY OP WRITING. to remember the power of the symbolic mark : whereas before, the properties of the thing or animal delineated were to be learnt. Tliis, together with their oiher marks by institution to design men- tal conceptions, would reduce the characters to (he present state of the Chinese*; and these were properly what the ancients call hierographic-al. Dr. Robert Huntington, in his account of the Porphyry Pillars tells us, that there are yel some ancient monu- nn n(s of this kind of writing remaining in Egypt t. Apuleius | describes the sacred book, or ritual of the Egyptians (as partly written in symbolic, and partly in these liierographic cha- racters of arbitrary institution, resembling the Chinese) in the fol- lowing manner. '* He (the hierophant) drew out certain books from the secret repositories of the sanctuary, written in unknown characters, which contained the words of the sacred formula com- pendiously expressed, partly by figures of animals, and partly by certain marks or notes intricately knotted, revolving in the manner of a wheel, and crowded together, and curled inward like the ten. drils of a vine, so as to hide the meaning from the curiosity of the profane." These hierographic characters are mixed with the sym- bolic in the ritual of Apuleius, and in the Bembine tables, as like- wise on several of the obelisks, where they are found mixed both with the proper hieroglyphic and with the symbolic. That letters were of great antiquity among the Egyptians, may reasonably be supposed, because we have indubitable proofs of their civilization ; but there is strong evidence to induce us to believe they were not the first inventors of an alphabet. — Mr. Jackson §, with great learning endeavours to shew, that letters were not in. vented or carried into Egypt by Taaut, or Thoth, the first Hermes and son of Misraim, who lived about five hundred years after the delude : but that they were introduced into that country by the second Hermes, who lived about four hundred years after the former. The second Hermes is by Plato called Theuth, who also styles him Counsellor and Sacred Scribe to King Tliamus. Dio. • These arbitrary marks, or marks by institution, srem to have led (he war to what is railed Nolae, or Short-hand. The notes of thnrt-hand are marks for words, nod the notes of hieroglyphics are mnrks for things. t See his Account of the Porphyry Pillars, Philosoph. Transact. No. clii. p. 624. J Mr tamorphoM s lib. ii. where he speaks of his initiation into the mysteries of Isis. ^ See Chronological Antiquities, vol. iii. p. 93—95. ANTIOUITT OP WRITING. 3fl7 dorus relates, that this Egyptian Hermes was the inventor of gram, mar ami music, and that he added many words to the Egyptian language : that he invented letters, rhythm, and harmony of founds. This was the Hermes so greatly celebrated by the Greek writers, who knew no older Hermes than him. Mr. Wise * insists, that Moses and Cadmus could not learn the alphabet in Egypt ; and that the Egyptians had no alphabet in their time. He adduces several reasons to prove that they had no al- phabet till (hey received what is called the Coptic, which was intro- duced either in the time of the Ptolomeys, or earlier, under Psam- mitichus or Amasis: and these letters, which are the oldest alpha- betic characters of the Egyptians that can now be produced, arc plainly derived from the Greeks It seems to us, that if the Egyp- tians used letters before the time mentioned by Mr. Wise, they were probably the characters of their neighbours the Phenicians. Herodotus, the most ancient Greek historian, whose works have reached us f , seems very sincere in his Egyptian history ; for he ingenuously owns, that all he relates before the reign of Psammi- tichus J is uncertain; and that he reports the early transactions of that nation on the credit of the Egyptian priests, on which he did not much depend. Diodorus Siculus is also reported to have been greatly imposed upon by the priests in Egypt. Manetho, the oldest Egyptian historian, translated out of the Egyptian info the Greek the Sacred Registers of Egypt, which are said, by Syncellus, to have been written in the sacred letters, and to have been laid up by the second Mercury in the Egyptian temples. This work was divided into three parts. The first, con. tained the history of the gods; the second, that of the demi-gods; the third, the dynasties, which ended in Nectanebus, King of Egypt, who was driven out by Ochus, three hundred and fifty yean before Christ. This author seems to have written his dynasties about two hundred and fifty years before the Christian aera, and, as • See his Enquiries concerning the first inhabitants, language, &c. of Eu- rope, p. 104—109. + He wrote his history of the first year of the eighty-fourth olympiad ; three hundred and ten after the foundation of Rome; «nd four hundred and forty- four before Christ. | He reigned about six hundred and sixty years before the Christian era. Syiicellug informs us, that the Greek* had very little commerce with the Egyp- tians till the reign of this king. ANTIQUITY OF WRITING. Syncellus tells us *, about (en years aft«r Berosus had written his Chaldean History. — Manetho allo w> the Eg) ptian gods to have been mortal men ; but his history was very much corrupted by the Greek?, and hath been calk-d in question by several writers, from the account which he himself gave of it. The objections to Marietho's Chronology are well founded ; for his number of three thousand five hundred and fifty years, belongs wholly to the successors of Menes, though he is more modest than many other writers of the Egyptian history. — Kusebius, in his Ca- non+, omits the first six'een dynasties of Manetho, and begins their chronology with the seventeenth. — After Cambyses had car. ried away the Egyptian records, the Egyptian priests, to supply their loss, and to keep up their pretensions to antiquity, began to write new records, wherein they not only unavoidably made great mistakes, but added much of their own invention, especially as to distant times. — Josephus, Plutarch, Porphyry, and Flusehius, speak well of Manetho. The curious fragments transcribed from him by Josephus, before his copies had been corrupted, seem to confirm the good opinion of these authors. PHENICIANS. WK shall next consider the claim of the Phenicians to the inven. tion of letters as we have the strongest proofs of the early civiliza- tion of this people. — Sanconiatho of Berytus, the most ancient, as also the most celebrated Phenician historian, compiled the Phenician history with great exactness, from the monuments and memoirs which he received from Jerobalus, priest of the god Jaco, and from their registers, which, Josephus says J, were carefully preserved in the inner parts of the temples; and in them were written the most memorable events, with regard to themselves and others. Philo of Byblus, a famous grammarian, who lived in the reigns of Vespasian, Titus, Domitian, Trajan, and Adrian, translated Sanconiatho's history, out of the Phtnician into the Greek tongue; and reduced it into eight books, but the original and the version are lost. — Eusebius who hath preserved several fragments of this history, gives the following account of it from Porphyry, who was * Chronograph, p. 18. + Chron. C.rrc. p. 89. | See Joscphus against Appion, book i. ANTICL'-ITY OF Wf'ITtNG, 369 a Phpnician of Tyre, and excellently versed in all ancient learning, He says*, that ^anooniarho of Byrvtus related, in his history, the Jewish aflfa'rs with ereat veracity: — (hat h<; dedicated his work to King Abifoalust and his history was allowed to be true, both by the king, and by tho.se who were appointed by him to examine it. This most ancient profane historian expressly relates, that let. ters were first invented in Phenicia, by Taaut, who lived in that country in the twelfth and thirteenthgenerations after the creation J. 44 Misor was the son of Hamyn. The sou of Misor was Taaut, " who invented the first letters for writing." The Egyptians call him Tooth ; the Alexandrians Thoyth, and the Greeks, Hermes, or Mercury. Sanconiatlio is said to have derived his first bonM^of the Orijii of Gods and Men, from writings ascribed to Taaut the first Hermes ; he makes Protogouus the first man, and JKon, or life, the first wo. man ; of Protogonus and yEon were begot two children Genus and Genea, who dwelt in Phenicia, and in time of a drought, prayed to the Sun, and worshipped him, as the only God and Lord of heaven. From these two persons Taaut is lineally descended, as we have just mentioned (in note ^ ) ; this author carries the worship of the Sun to the second man of human race. Philo observes, that the Greeks damned most of Sanconiatho's history of the gods to themselves, to which they added many pleasing fables. Hence it was, saith he, that Hesiod, and the itinerary poets, sung about in their poems, genf-rations of gods and battles of giants and Titans ; and men being accustomed from their infancy to hear nothing but these fictions, * See Kusebius Prasparat. Kvang. lib. i. c. 9, p. 30, &c. f Kin^ Atiihnliiii began to reign one thousand seventy-three years before Chri>t ; he was the father of Hiram, who was Solomon's ally* f The gem-nlrgy of Taaut, as given by Sancouiatho : 1 Protoeonus, £> Hvp-uranius, or Memruinus, 9Asrovenis$ (Noah), 2 Genus, 6 . \grru-, 10 Amy n, (Hamyn, or Ham) 3 Ur, Phos, 7 Chrj>or, 11 Misor, or Miiraim, 4C.-K.Mii., STechniles, 1* Taaut. This author makes mankind live in Phenicia; and pl.i< e Hypsuranius at Tyre. The plan of the history is quite different from that of Moses, and seems to be jjroui'ded upon a very different tradition relating to the first ages. Some writers have atirmptfd to prove the works of this author spuriou« ; but tfvir argument* are so frivolous that th.-y scarcely deserve an answer. 8ft- many curious par- ticulars concerning the author and hi* writings, in the Univ. fli-t. v.il. i pre- face, p. 10, and p. S3, 181, 187, 189, 37 1 nomical observations, and naval and martial arts *. — Curtius says, that the Tyrian nation are related to be the first, who either taught or learned letters H ; and Lucan says, the Fhenicians were the first who attempted to express sounds (or words) by letters J. To these authorities may be added that of Eusebius§, who tells us, from Porphyry, that " Sanconiatho studied with great application the writings of Taaut, knowing that he was the first who inventedlt ters ;" and on these he laid the foundation of his history. It is observable, that the Greek writers seem to have known no older Hermes than the second Hermes or Mercury, who is record, ed to have lived about four hundred years after the Mezrite Taaut, or Hermes ; which second Hermes, Plato calls Theuth, and coun- sellor and sacred scribe to king Thamus, but it is not said that h« ever reigned in Egypt : whereas the Mezrite Taaut, or Athothf-s, as Manetho calls him, was the immediate successor of Menes, the first king of Egypt. The second Mercury, if we believe Manetho, composed several books of the Egyptian history, and many incredi- ble things are attributed to him ; who being more known, and more famous in Egypt than the Mezrite Hermes, and having im- proved both their language and letters, the Egyptians attributed the arts and inventions of the former, to him ||. The Phenician language has been generally allowed to be, at least a dialect of the Hebrew; and though their alphabet doth not en. tirely agree with the Samaritan, yet it will hereafter appear, that there is a great similarity between them H. Arithmetic and Astro. nomy were much cultivated by them, in the most early ages **. * Ipsa gens Phacnicutn in gloria raagna literarum inventionis et siderum, na- valiumque ac bellicarutn artium. Nat. Hist. lib. v. c 12. + Si famae libet credere htec (Tyriorum) gens literas-prima aut docuit, aut didicit, lib. vi. c. 1. $ Phcenices prirai, famse si creditor, aussi^ Mansuram rudibus voccm signare figuris. Lib. iii. v. 220, 281. ;, De abstinent, lib. ii. sect. 56. H Concerning this second Hermes, see Du Pin's Universal Historical Library vol. i. p. 34 and 52 j and Jackson's Chronol. Antiq. vol. iii. p. 94. 5 They had circumcision, as well as other customs, in common with the He- brews, saith Herodotus. *« They were from the beginning, as it were, addicted to philosophical exer- cises of the mind } insomuch that a Sidonian, by name Moschus, is said to liavf taught the doctrine of Atoms, before the Trojan war , and Abdomenus of Tyre, challeuged Solomon, though the wisest king upon earth, by the tubtlu qnt-ui 372 ANTIQUITY OF WRITING. Their fine linen, their purple, and (heir glass, Mere superior to those of any other people ; and (heir extraordinary skill in architec- ture and other arts, was such, that whatever was great, elegant, or pleasing, whether in buildings, apparel, vessels, or toys, were dis- tinguished by the epithet of Tyrian or Sidonian *. The Si Ionia is or Phenicians were the first people who ventured out to sea in ships t ; they were; the greatest commercial people of all antiquity, and engrossed all the commerce of the western world. This very early and high degree of civilization, justly entitles them to urge the strongest pretensions to the first use of alphabetic cha. racters J. proposed to him. Phenicia continued to he one of the scats of learning ; and both Tyre and Sidon produced their philosophers of later ages ; Bocthus and Dindatus of Sidon, Autlpater of Tyre, and Apollonius of the same place, gave an account of the writ inland disciples of Zcno. Universal Ili-t. vol. ii.p. 846. •Tyre and Sidon were the principal cities in Pheoicia.— See the Treaty which king Solomon entered into with Hiram king of Tjre, for artificer*, ;i< it is recorded in '2 Ciiron.chap. ii. v. 7 — 16. Hiram began to rei^n in (he one thousand three hundred and twenty-ninth year after lite deluge, and one thou- sand and twenty years before the Christian sera. Solomon also contracted u ith king Hiram, for >h':ps to bring gold abd precious »tones fur ornamenting bis buildings. 2 Chron. v. 18, and chap. ix. ». 10 and 18. •(• Sanconiatho says, that tiie I'hemcians made sliips of bur ten in which they sailed in the time of Saturn, 01 Cronus. And D'mny-iu- -;iy>, the Plieniciaiij were the first wlio ventured to sea iu ships. Pericg. v. 907. f The learned authors of the Nouveau Traite de Diplomatique, not only cor- roborate but illustrate thisopinion.— Knfin, toutdepose exclusivementen faveur de 1'antiquitc de la langue Phenicienne. Par la Phenicie on n'entend pas seulcment les villes de la cole maritime dela Palestine, mais de plus In Judee & les pays des Clianancens & den Hebreux. Herodote lni-m£mc, lib. ii.col. 104, par les Plieniciens de.signoit (videmment les Hebreux ou Ii s Juifs, puisque, selnn lui,les Pli6niciens se faisoient circoncire, & que les Tyriens, le^ Sidonieni,&c. n'^toi'-nt point dans cet usage. Par ecri'ure Phinicienne, on entend done, la Sainaritaine, c'est-a dire r.-ineien Hebreu, [Sovrtit,Dititriatwn sur le$ Medaillet Hebrai'iue p. -I ;] different de I'Htbreuquarri on Clialdaique, qui est le modern.-, que les Juis out adopte depu'is la captmtc de Babylone, aiiisi que 1'ont pensee S. Jerome, S. Irene, S. Clement d'Alexandrie, &c. &c. Lesauteun qui adjugent I'antiquite a recriture S;imarilainesonf snns notnbre. Genebrard, Bellarmin, le Pere Morin, M. Huet, Dom. Montfaiicon, Doin. Cal- met, M. Renaudot, Joseph Scaliger, Grotiiu, Casiubon. Walton, Hoc hard, Vos- si us, Pridcaux, Capelle, Simon, Sit •. &f. se sont hautcment derlare the early use of Utters. — The next nation that claims attention is the Syrian. The language of the Syrians is mentioned in the Universal History., vol. i. p. 3 17, 348 ; and was a distinct tongue in tin- dajs of Jacob. It was also (he language of Mesopotamia and Chaldea. — As to the arts and learning of the Syrians, they were by some anciently joined will) the Phcnicians, as the first inventors of letters ; but, without entering into this matter, certain it is, that -they yielded to no nation inhuman knowledge, and skill in the fine arts. From their happy situation they may almost be said to have been in the centre of the old world : and, in the zenith of their em. pire, they enriched themselves with the spoils, tribute, and com- merce, of the nations far and near, and arose to a great pitch of splendour and magnificence, which are the chief eucouragers of ingenuity and industry *. Their language is pretended to have been the vernacular of al! the oriental tongues, which was divided into three dialects : First, the Aramean, used in Mesopotamia, and •by the inhabitants of Roha, or Edesa, of Harram, and the Outer Syria : Secondly, the dialect of Palestine, spoken by the inhabitants of Damascus, Mount Libanus, and the Inner Syria : Thirdly, the Chaldce or Nabathean dialect, the most unpolished of the three, and spoken in the mountainous parts of Assyria, and the villages of Iruc or Babylonia. It hath been a received opinion, that no nation of equal antiquity had a more considerable trade than the ancient Syrians. They had many valuable commodities of their own to carry into other parts ; and, by their vicinity to the river Euphrates, it is evident that they traded with the eastern nations upon that river very early. The easy and safe navigation of the Euphrates, when compared with that of the sea, may incline us to consider them, as older merchants than the Edomites, or even the Phenicians, who confessedly ingrossed }he trade of the western world. The Syrians therefore are sup- posed to have been the first people who brought the Persian and Indian commodities into the west of Asia. It seems therefore that the Syrians carried on an inland trade, by engrossing the com. » The altar at D.inwsru<=, w liicli so ravished Ahaz king of Judah, serves as * j.« rimcn of the skill of their artificers. ANTIQUITY OF WRITING. o?5 merce of the Euphrates ; whilst the Phenicians traded to the most distant countries. Notwithstanding the above circumstances, which may seem to fa- vour the claim of the Syrians, the oldest characters or letters of that nation that are at present known, arebut aboutihree centuries before the birth of Christ. Their letters are of two sorts : the Estrangt-lo, which is the more ancient ; and that called the Fshito, the simple or common character, which is more expeditious and beautiful *. INDIANS. THE period of time is happily arrived, when the study of oriental literature is not only become useful, but fashionable. The learned Sir William Jones greatly facilitated the attainment of the know, ledge of the Persian language ; Mr. Richardson that of the Arabic ; and Doctor Woide, the Egyptian and the Coptic ; by the publica. tion of their respective grammars. Mr. Halhed, the editor of a work intitled the Gentoo Laws, hath written a grammar of the Shanscrit language t, which he informs us, is not only the grand source of Indian literature, but the parent of almost every dialect from the Persian gulph to the Chinese seas, and is a language of the most venerable antiquity ; and, although at present shut up in the libraries of Bramins, and appropriated solely to the records of their religion, appears to have been once current over most of the oriental world, as traces of its original extent may still be dis- covered, in almost every district of Asia. " There is,'' says Mr. Halhed, " a great similarity between the Shanscrit words and those of the Persian and Arabick, and even of Latin and Greek ; and these, not in technical and metaphorical terms, which the mutation of refined arts and improved manners might have occasionally introduced, but in the main ground. works of language; in monosyllables, in the names of numbers, and the appellations of such things as would be first discriminated, on the immediate dawn of civilization. The resemblance which may be observed in the characters upon the medals and signets of various districts of Asia, the light which they reciprocally reflect upon each * See these characters in the Univ. Hist. vol. ii. p. 994. •f This ingenious gentleman, assisted by Mr. Wilkins, a descendant of the learned bishop of that name, not only formed ihe ij pes of the (ienioo alp Irabel , tout printed this grammar, at lloogly in Bengal, 4to. 177*. 2»4 376 ANTIQUITY OF V/RITINO. other, and the general annlo.y which they all boar to the grand prototype. iifFords another ample field for curiosity. That coins of Assam, N,I. ;ml, ( n-hmiria, and many other king, doms, are all stamp) with Shunscrit letters, and mostly contain al- lusions to the old Mia Mr. Richardson, hi his Arabic Grammar, observes, as a proof of the richness of this language, that it consists of two thousand ra. dical words. The old Arabic characters are said to be of very high antiquity ; lor ttbn Hashem relates, that an inscription in it was found in Y'aman, as old as the time of Joseph. These traditions may have given occasion to some authors to suppose the Arabians to have been the inventors of letters ; and Sir Isaac Newton * sup. poses, that Moses learned the alphabet from the Midianites, who were Arabians. The Arabian alphabet consists of twenty.eight letters, which are somewhat similar to the ancient Kufic, in which characters the first copies of the Alcoran were written. The present Arabic characters were formed by Ebn Moklah, a learned Arabian, who lived about three hundred years after Maho. met. We learn from the Arabian writers themselves, that their alphabet is not ancient. — Al Asmahi says, that the Koreish were asked, " From whom did you learn writing ?" and that they an. swered, ** From Hirah." That the people of Ilirah were asked, " From whom did you learn writing ?'' and they said " From the Ambarites." — Ebn Al Habli and Al Heisham Ebn Admi relate, that Abi Sofian, Mahomet's great opposer, was asked, u From •whom did your father receive this form of writing ?" and that he said, " From Ashlam Ebn Sidrah j" and. that Ashlam being asked, f ' From whom did you receive writing ?" his answer was, " From the person that invented it, Moramer Ebn Morrah ;" and that they received this form of writing but a little before Islamism t. OBSERVATIONS AND REFLECTIONS. BEFORE we conclude, we shall make a few reflections on the foregoing claims of different nations to the invention of letters. The vanity of each nation induces them to pretend to the most early civilization ; but such is the uncertainty of ancient history, that it is difficult to decide to whom the honour is due. It however should seem, from what hath been advanced in the course of this part of our inquiry, that the contest may be confined to the Egyptians, the Phenicians, and the Chaldeans. The Greek writers, and most * Chronology of Egypt, p. 205, 8vo. edit. f Wise, en the first inhabitants, &c« of Europe, p. 99. 380 ANTIQUITY OF WHITING. of those who have copied them, decide in favour of E«ypt, because their information is derived froM the Egyptians tbenuel vet. The positive claim of the Phenichns, doth not depend upon the sole testimony of Sanconiatho ; the en (lit of his history is so well sup- ported by Philo of Kiblus his translator, Porphyry, Pliny, Curtius, Lucan, and other ancient authors, who mi^ht have seen his works entire, and whose relations deserve at least as much credit astho-e of the Egyptian and Greek writers. It must be allowed, that San. coniatho's history contains many fabulous traditions ; but does not the ancient history of the Egyptians, the Greeks, and most other nations, abound with them to a much greater degree ? The frag- ments which w e have of this most ancient historian, are chiefly furnished by Eusebius, who took all possible advantages to repre- sent the Pagan writers in the worst light, and to render their theology absurd and ridiculous. Cicero * distinguishes five Mercuries, two of which are Egyptian. Authors are much divided as to the ages in which they lived, but the most ancient is generally allowed to be the Phenician Taaut, •who passed from thence to Kg\ pt. It is probable that he might teach the Egyptians the use of letters ; and that the second Taaut, Mercury, or Hermes Trismegistus, improved both the alphabet and language, as Diodorus and others have asserted. The Phenician and Egyptian languages are very similar, but the latter is said to be more large and full, which is an indication of its being of a later date. The opinion of Mr. Wise, that the ancient Egyptians had not the knowledge of letters, seems to be erroneous : as they had commer. cial intercourse with their neighbours the Phenicians, they probably had the knowledge of letters, if their policy (like that of the Chinese at this day) did not prohibit the use of them. The Chaldeans, who cultivated astronomy in the most remote mges, used symbols, or arbitrary marks, in their calculations ; and we have shewn that these were the parents of letters. This circum- stance greatly favours iheir claim to thf invention, because Chaldea, and the countries adjacent, are allowed by all authors, both sacred tnd profane, to have been peopled before Egypt ; and it is cer. tain that many whole nations, recorded to be descended from Shem • De Nat. Dcor. lilt. iii. ANTIQUITY OF WRITING. 381 and Japhet, had their letters from the Pheuiciaus, who were descended from Ham *. It is observable, that the C'-aldeans, the Syrians, the Phenicians, and Kc.vptians, all bordered upon each other ; and as the Phenicians \\-n- die greatest, as will as the most ancient commercial nation, it is very probable, that they communicated letters to the Egyptians, the ports of Tyre and ^idon, and those of the Egyptians, being not far distant from each other. Mr. Jackson is evidently mistaken, when he says, that letteri were invented two thousand six hundred and nineteen years before the birth of Christ. The deluge, recorded by Moses, was two thousand three hundred and forty. nine years before that event ; and if letters were not invented till five hundred and fifty years after, as he asserts, we must date their recovery only one thousand sev^n hundred and ninety. nine years before the Christian zra, which is four hundred and ten years after the reign of Menes, the first king of Eiiypt. who (according to Geo. S) ncellus and others) is said to have been the same person with the Misor of Sanconiatho, the Mizraim of the Scriptures, and the Osiris of the Egyptians ; but whether this be true or not, Egypt is frequently called in the Scriptures, the land of Mizraim +. This Mizraim, the second son of Amyn or Ham, seated himself near the entrance of Egypt at Zoan, in the year before Christ two thousand one hundred and eighty-eight, and one hundred and sixty years after the flood ; he afterwards built Thebes, and some say Memphis. He is by Herodotus, by Diodorus, Eiatostheoes, and Africanus, by Eusebiusand Syncellus, called Menes t. Before the time that Mizraim went into Egypt, Taaut his son had invented letters in Pitenicia ; and if this invention took place ten years before the migration of his father into Egypt, as Mr. Jackson supposes, we can trace letters as far back, as the year two thousand one hundred and seventy eight before Christ, and one hundred and fifty after the deluge recorded by Moses ; and beyond this period, the written annals of mankind, which have bven hitherto trans. * Misraim, the son of Ham, led colonies into K<%pi, and laid the foundation of a kingdom, which lasted one thousand six hundred and sixty-three yeart) whence Egypt is, in the Holy Scriptuic-, called the land of Ham. + Universal History, vol. v. p. 3e that the two first of tlu-se nations write with small reeds bearing the hand exceedingly lightly. Tavernier, in one of his voyiiges says the same of the Persians. Raiiwo'lf, who travelled in 1.583, relates, that the Turks, Moors, and eastern na. tio'is, use can* s for pens, which are small and hollow within, smooth without, and of a brownish red colour +. The canes iu Persia are cut in March, which they dry in the smoak for about six months ; those which are covered with a fine varnish of black un ! yellow, are esteemed the best for writing with. The Indians more frequently write with the cane called bamboo, which is cut about tin* length and thickness of our pens. Pencils made of hair are used by the Chinese for their writing : they first liquify their ink, and dip their pencils into it. The large capital letters were made with hair pencils from the time of the Roman emperors till the sixteenth century. After the invention of printing they were drawn by the illuiiiimtors. Quills of geese, swans, peacocks, crows, and other birds hare been used in these western parts for writing with, but how long is not easy to ascertain. St. Isidore of Seville, who lived about the middle of the seventh century, describes a pen made of a quill as used in his time. u Instruments scriba: calamus et >.eiina ; t-x his • Plin. Hist.l. xvi.c. 36. f Lib. liv F.piKr. 5t. f Ranwolff** Travel*, p. 87. INKS. 385 cnini verba paginis infiguntur ; sed calamus arboris est, penna avis, cujus acumen dividitur in duo *." Some of the instruments necessary for the occupation of a libra- rius or book. writer are delineated in a book of the four gospels in the Harleian library (No. 2820), written in Italy in the tenth cen- tury. The vellum, on which this book is written, is stained of dif- ferent colours at the beginning of each gospel. [Astle. SECTION V. Inks. INK has not only been useful in all ages, but still continues abso- lutely necessary to the preservation and improvement of every art and science, and for conducting the ordinary transactions of life. Daily experience shews, that the most common objects, generally prove most useful and beneficial to mankind. The constant occa- sion we have for ink, evinces its convenience and utility. From the important benefits arising to society from its use, and the inju. ries individuals may suffer from the frauds of designing men in the abuse of this necessary article, it is to be wished that the legislature would frame some regulation to promote its improvement, and prevent knavery and avarice from making it instrumental to the accomplishment of any base purposes. Simple as the composition of ink may be thought, and really is, it Is a fact well known, that we have at present none equal in beauty and colour to that used by the ancients ; as will appear by an in. spection of many of the MSS. above quoted, especially those writ, ten in England in the times of the Saxons. What occasions so great a disparity ? Does it arise from our ignorance, or from our want of materials ? From neither, but from the negligence of the present race ; as very little attention would soon demonstrate, that we want neither skill nor ingredients to make ink as good now, as at any former period. It is an object of the Utmost importance that the records of par. liament, the decisions and adjudications of the courts of justice, conveyances from man to man, wills, testaments, and other instru- ments, which affect property, should be written with ink of such •* kitl, Hi»p. Oiig. lib. vi. cap. 14. ?OL. TI. 2 C 3.ses of colour cannot be successfully delivered from wood ; wherefore they are obliged, in those parts of their patterns, to use bits of smooth norn. out beaver-hat, which might very well be pressed on the glass-plate. However, from what we every day see effected in the case of prints affixed to glass without any of the paper remaining, and also of copper-plate embellishments upon porcelain and queen's ware, we doubt not that the picture, while fresh, may, by well managed pressure, be transferred from the paper to an even plate of ground glass coated with a proper gluten which shall not, at least not ma. terially, ofluscate its transparency ; and experiment must determine whether the paper may afterward be gently drawn or peeled off, or must be burned away, or destroyed by a corrosive liquid, if any such can be found which will not injure the colours. Suppose, however, the operation of removing the paper to be satisfactorily performed, proceed we now to secure the indelibility of the picture. Let a square plate of cast-iron, an inch or two in thickness, and as level and smooth as possible, be furnished on every side with a metal ledge rising an inch or more in height, which ought to be iu two separate pieces, the one permanently fastened to the plate, the other capable of being removed at pleasure, for the purpose of lay- ing in and taking out the glass without violence. Within that ledge let the glass be fitted, closely touching it on every side, and lying with the painted surface uppermost. Upon this lay another plate of glass, fitted in the same manner. Let, now, the metal frame, with the inclosed glasses, be exposed to the action of fire until the glass plates, without being melted to absolute fluidity, shall nevertheless become sufficiently soft to coalesce into one body under a strong pressure. The body which conveys the pressure, and lies in immediate contact with the glass, must «]».:illy fit and completely fill the entire space between the ledges, that there be no room for the soft glass to spread in any direction. Those who have witnessed the process pursued in softening tortoise-shell in the fire, and pressing it into the various shapes of ENAMELLING. 419 snuffboxes, etuit, &c. &c. will not conceive much difficulty in this use of (he glass. It may be managed by the aid of a machine some- what similar to, but more powerful than, a common printing press, with a solid metal platine, to fit and fill the frame, as above ; though much better contrivances may be found among the multifarious en. gines employed at Birmingham for the purposes of coining, and striking the heavy dies, t:,an any we can possibly suggest. In whatever manner the two glasses may be pressed into union, the united body may be afterward ground ami polished. [Pantologia. Walpole. SECTION III. Enamelling. THB delicate and beautiful art of enamelling consists in the application of a smooth coating of vitrified matter (transparent or opaque, and with or without colour, figures and other ornaments), to a bright polished metallic substance. It is, therefore, a kind of varnish made of glass, and melted upon the substance to which it is applied, and affording a fine uniform ground for an infinite vari. ety of ornaments which are also fixed on by heat. The general principles on which enamelling is founded, are on the whole very simple, but, perhaps, there is none of all the che- mico- mechanical arts which requires, for the finer parts, a greater degree of practical skill and dexterity, and of patient and accurate attention to minute processes. The concealment observed by those who profess this art is pro- portioned to the difficulty of acquiring it ; the general chemist must, therefore, content himself with the general principles of enamelling, and the detail of those particulars that are commonly kno«n. Though the term enamelling is usually confined to the ornamen. tal glazing of metallic surfaces, it strictly applies to the gl.izin" of pottery or porcelain, the difference being only that in the latter the surface is of baked clay. With regard to the composition of co- loured enamels (which are all tinged by different metallic oxyds ) a very general account of the substances used will suffice in this place, the rest of the subject having been treated of in the article of coloured glass. The enamelling on metals, therefore, will only be noticed in this place. The only metals that are enamelled, V E 2 420 EN A MULLING. are gold and copper ; and w!th the latter the opaque enamels are only used. Where the enamel is transparent and coloured, the metal chosen should he of that kind, as not only to have its sur- face unalterable when fully red hot, but also to be in no degree chemically altered by the close contact of melted glass, contain, ing an abundance of some kind of metallic oxyd. This is the chief reason why coloured enamelling on silver is impracticable, though the brilliance of its surface is not impaired by mere heat, for if (for example) an enamel made yellow with oxyd of lead, or antimony is laid on the surface of bright silver, and kept melted on it for a certain time, the silver and the enamel act on each other so power- fully, that the colour soon changes from a yellow to an orange, and lastly to a dirty olive. Copper is equally altered by the co- loured anamels, so that gold is the only metal which can bear the long contact of the coloured glasses at a full red heat, without being altered by them. The simplest kind of enamel is that fine white opaque glass, which is applied to the dial plate of watches. The process of lay. ing it on (which may serve as a general example of the art) is the following. A piece of thin copper sheet, hammered of the requisite con- vexity, is first accurately cut out, a hole drilled in the middle for the axis of the hands, and both the surfaces made perfectly bright with a scratch brush. A small rim is then made round the circumference, with a thin brass band rising a little above the level, and a similar rim round the margin of the central hole. The use of these is to confine the enamel when in fusion, and keep the edges of the plate quite neat and even. The substance of the enamel is a fine white opaque glass, the material of which will be presently mentioned. This is bought in lump by the enamellers, and is first broken down with a hammer, then ground to a sufficiently fine powder, with some water, in an agate mortar ; the superfluous water being then poured off, the pulverised enamel remains of about the consistence of wetted sand, and is spread very evenly over the surface of the copper-plate by many dexterous manipulations. On most enamel- lings, and especially on this, it is necessary also to counter ena- mel the under concave surface of the copper plate", to prevent its being drawn out of its true shape, by the unequal shrinking of the metal and enamel on cooling. For this kind of work, the counter ENAMELLING. 421 enamel is only about half the thickness on the concave as on the convex side. For flat plates, the thickness is the same on both sides. The plate, covered with the moist enamel powder, is warmed and thoroughly dried, then gently set upon a thin earthen ring, that supports it only by touching the outer rim, and put gradually into the red hot muffle of the enameller's furnace. This furnace is constructed somewhat like the assay furnace, but the upper part alone of the muffle is much heated, and some peculiarities are ob- served in the construction, to enable the artist to govern the fire more accurately. The precise degree of fire to be given here as in all enamelling, is that at which the particles of the enamel run together into an uniform pasty consistence, and extend themselves evenly over the surface, shewing a fine polished face, carefully avoiding on the other hand so great a heat as would endanger the melting of the thin metallic plate When the enamel is thus seen to sweat down, as it were, to an uniform glossy glazing, the piece is gradually withdrawn and cooled, otherwise it would fly by the action of the cold air. A second coating of enamel is then laid on and fired as before, but this time the finest powder of enamel is taken, or that which remains suspended in the washings. It is then ready to receive the figures and division marks, which are made of a black enamel, ground in an agate mortar, with much labour, to a most impalpable powder, worked up on a pallet with oil of lavender, or spike, and laid on with an extremely fine hair brush. The plate is then stoved to evaporate the essential oil, and the figure burnt in as before. The polishing with tripoli, and minuter parts of the process, need not be here mentioned. If the enamel be chipped off a dial plate (which may be done with the utmost ease, by bending it backwards and forwards, as the adhesion between the metal and glazing is very slight) the part immediately ia contact with the copper will be found deeply and nearly -uniformly browned, which shews how unfit copper alone would be for the transparent enamels. The* regulation of the fire appears to be the most difficult of all the parts of this nice process, particularly in the fine enamelling of gold for ornamental purposes, of designs, miniatures, and the like, where three, four, or sometimes five separate firings are re. S V I 422 ENAMELLING. quired. If the heat is too low, the enamel does not spread and vitrify as it ought ; if too high, it may be enough to melt the metal itself, whose fusing point is but a small step above that of the ena. mel, or else (what is an equal mortification to the artist) the d< li. cate figures, laid on with so much care and judgement, meltdown in a moment, and the piece exhibits only a confused assemblage of lines, and fragments of designs. The exact composition of the opaque white enamel, is a matter of considerable importance, and is procured by the enamellers from persons whose business it is to prepare it. A good enamel of this kind, fit to be applied to porcelain and metals, should be of a very clear fine white, so nearly opaque, as only to be translucent at the edges ; and at a moderate red heat it should run into that kind of paste, or imperfect fusion which allows it to extend itself freely and uniformly, and to acquire a glossy even surface, without, however, fully melling into a thin glass. The opaque white of this enamel is given by the oxyd of tin, which possesses, even in a small proportion, the property of rendering vitrescent mixtures white and opaque, or in still less proportion, milky; and when otherwise coloured, opalescent. The oxyd of tin is always mixed •with three or four times its quantity of oxyd of lead ; and it ap. pears necessary that the metals should be previously mixed by melting, and the alloy then calcined. The following are the direc. tions given by Clouet for the composition of this enamel. Mix 100 parts of pure lead with from 20 to 25 of the best tin, and bring them to a low red heat in an open vessel. The mixture then burns nearly as rapidly as charcoal, and oxidates very fast. Skim off the crusts of oxyd, successively formed, till the whole is tho- roughly calcined. It is better then to mix all the skimmings, and a"ain heat as before, till no flame arises from them, and the whole o is of an uniform grey colour. Take 100 parts of this oxyd, 100 of sand, and 25 or 30 of common salt, and im-lt the whole in a moderate heat. This gives a greyish mass, often porous and appa. rently imperfect, but which, however, runs to a good enamel when afterwards heated. This is the enamel used for porcelain, but for metals and finer works the sand is previously calcined in a very strong heat with a fourth of it* weight, or, if a more fusible com. pound is wanted, as much of the oxyd of tin and lead as of salt is taken, and the whole melted to a white porous mass. This is then employed instead of the rough sand as in the above-mentioned pro. ENAMELLING. 4 .! < -cess. The above proportions, however, are not invariable, for if more fusibility is wanted, the dose of oxyd is increased, and that of the sand diminished, the quantity of common salt remaining the same. The sand employed in this process, according to Mr. Clouet, is not the common sort, however fine, but a micaceous sand, in •which the mica forms about one-fourth of the mixture. Neri, in his valuable treatise on glass-making, has given long ago the following proportions for the common material of all the " opaque enamels, which Kunckel and other practical chemists have confirmed. Calcine 30 parts of lead, with 33 of tin, with the precautions mentioned above. Take of this calcined mixed oxyd 50 pounds, and as much of powdered flints (prepared by being thrown into water when red hot, and then ground to powder), and «ight ounces of salt of tartar; melt the mixture in a strong fire kept up for ten hours, after which reduce the mass to powder. This is the common material for the opaque enamels, and is of a grey white. To make this fine enamel quite white, mix six pounds of this material with 48 grains of the best black oxyd of manga- nese, and melt in a clear fire. When fully fused, throw it into cold water, then re.melt and cool as before two or three times, till the enamel is quite white and fine. Kunckel observes on this pro- cess, that he tried it without the oxyd of manganese, but the ena- mel, instead of being milk white, was blueish and not good, so that there is no doubt but that this oxyd is highly important. If too much is used, the enamel becomes of a rose purple. For fur. ther observations on this subject, see the article Glass. Colour, ed enamels are composed of a common basis, which is a fusible mixture of verifiable materials, and of some metallic oxyd. In general, the coloured enamels are required to be transparent, in which case, the basis is a kind of glass, composed of borax, sand, and oxyd of lead, or other vitresccnt mixtures, in which the proportion of saline or metallic 11 ux is more or less accord, ing to the degree of heat that the colouring oxyd will bear with, out decomposition. When the coloured enamel is to be opaque, or opalescent, a certain portion of the white opaque enamel, or of the oxyd of tin, is added to the mixture. The most beau, tiful and costly colour known in enamelling, is an exquisitely line rich red, with a purplish tinge, given by the salts and oxyds of gold, especially the purple precipitate, formed by tin in ons 2E4 424 ENAMELLING. form or other, and nitro muri.it of »<>U1, and also by the fulminat- iiU ;.old. This l>e;iutiuil rulour iv|irires much skill in (lie artist to be fully brought out. It is said, that when most perfect, it should come from (he fin- quite colourless, and afterwards red iv<; its colour by the Hume of a candle. Cold colours will not bear a violent fire. Oth« r and common reds are given by the oxyd of iron, but this requires the mixture of alumine, or Borne other substance refrac- tory in the fire, otherwise at a full rod heat the colour will degene- rate into black. Yellow is given eilhrr by the oxyd of silver alone, or by the oxyds of lead and antimony, with similar mixtures to those re- quired for iron. The silver is as tender a colour as gold, and rea- dily injured or lo< to be painted ->n the unwaxed side with colours pre- pared and tempered with wat< r ; and when the picture i* finished it must be brought near the I; re, that the wax may melt and fix the colours. Thi> method, however, can only be applied to cloth or paper, through the substance of which the wax may pass ; but in wood, stone, metals or Blaster, the former method of count Caylus must be ob^erv d. Mr. Muntz has also discovered a method of forming grounds for painting with crayons, and fixing these, as well as wafer-colours, emplo\ed with the pencil. On the unwaxed side of a linen cloth, stretched and waxed as before, lay an even and thick coat of the colour proper for the ground : having prepared this colour by mix. ing some proper pigment with an equal quantity of chalk, and tem- pering them with water. When the colour is dry, bring the pic- ture to the fire that the wax may melt, pass through the cloth, and fix the ground. An additional quantity of wax may be applied to the hack of the picture, if that which was first rubbed on .should not be sufficient for the body of colour ; but as this must be laid on without heat, the wax should be dissolved in oil of turpentine, and applied with a brush, and the canvas be ag.iin exposed to the fire, that the fresh «uppiy of wax n.ay pass through the clolh, and be absorbed by the colour ; and thus a firm and «oo-l body will be formed for working on with the crayon-. If * loth and paper are joined together, the cloth must be first fixed to the str -ini'ig frame, aud then the paper must be pasted to it with a composition of paste made with wheaten flour, or starch, and water, and about a twelfth part of its weight of common turpentine. The turpentine must be added to the paste when it is almost sufficiently boiled, and the composition well stirred, and !• ft to bimnier over the fire for five or six minutes ; let wax be dissolved in oil of turpentine to the consistence of a thin paste ; and when the cloth and pap T are dry, let them be held near a fire ; and with a brush lay a coat of the wax and turpentine on both sides of the joined cloth and paper, t« 4-8 ENCAUSTIC PAINTING. such a degree of thickness, that both surfaces may shine through- out without any appearance of dull spots. Tln-n expose the cloth to the (ire or to the sun ; by which means the oil will evaporate, and (he wax become solid, and be (it to receive any composition of colour proper for a ground, which is to be !;iid on as abuve di- rected in the case of cloth without paper. Almost all the colours that are used in oil. painting may be also applied in the encaustic method. Mr. Mun;z objects, indeed, to brown light pink, and unburot terra di Sienna; because these, oa account of their gummy or stony texture, will not adr.iit such a cohesion with the wax as will properly fix them; but other colours •which cannot be admitted in oil-painting, as red lead, red orpi. iiient, crystals of verdigris, and red precipitate of mercury, may be used here. The crayons used in encaustic painting are the same with those used in the common way of crayon painting, ex. cepting those that in their composition are too tenacious ; and the method of using them is the same in both cases. The encaustic painting has many peculiar advantages ; though the colours have not the natural varnish or shining which they ac- quire with oil, they have all the strength of paintings in oil, and all the airiness of water colours, without partaking of the a| parent character or defects of either ; they may be looked at in any light and in any situation, without any false glare : the colours nre firm, and will bear washing; and a picture, after having been smoked, and then exposed to the dew, becomes as clean as if it had been but just painted. It may also be retouched at pleasure, without any detriment to the colours : for the new colours will unite with the old ones, without spots, as is the case in common sis- painting ; nor is it necessary to rub the places to be retouched with oil as in oil pictures; it is not liable to crack, and easily repaired, if it should chance to suffer any injury. The duration of this painting is also a very material advantage ; the colours are not liable to fade and change ; no damp can affect them, nor any corrosive sub- stance injure them ; nor can the colour fall off in shivers from the canvas. However, notwithstanding all these and other advanta es enumerated by the abbe Mazeas and Mr. Muntz, this art has not yet been much practised. Many of these properties belong to a much higher species of encaustic painting afterwards discovered in England, the colours of which are fixed by a very intense heat ; nor are the colours or grounds on which they are laid liable (o be ENCAUSTIC PAINTING. dissolved or corroded by any chemical menstrum ; nor, like the glassy colours of enamel, to ru:i out of the drawing on the fire. This method is described in the second part of the xlixth volume of the Philosophical Transactions, No. 100. Yet, notwithstanding the ingenuity of this communication, we find the ancient or some similar method of painting in wax remained a desideratum upwards of twenty-five yearsj and till, in 1787, a method was communi- cated to the Society of Arts by Miss Greenland. The ground of her information she received at Florence, through the acquaintance of an amateur of painting, who procured her the satisfaction of seeing some paintings in the ancient Grecian style, executed by sig- nora Parent!, a professor of that place, who had been instructed by a Jesuit at Pavia, the person who made the farthest discoveries in that art. Miss Greenland's friend, knowing she was fond of paint, ing, informed her what were the materials the paintress used, but could not tell her the proportions of the composition ; however, from her anxiety to succeed in such an acquisition, she made va. rious experiments, and at last obtained such a sufficient knowledge of the quantities of the different ingredients as to begin and finish a picture, which she afterwards presented to the society for their inspection. Her method is as follows : u Take an ounce of white wax, and the same weight of gum mastich powdered. Put the wax in a glazed earthen vessel over a very slow fire ; and when it is quite dissolved, strew in the mastich, a little at a time, stirring the wax continually until the whole quantity of gum is perfectly melted and incorporated : then throw the paste into cohl water, and when it is hard, take it out of the water, wipe it dry, and beat it in one of Mr. Wedgewood's mortars, observing to pound it at first in a linen cloth to absorb some drops of water that will remain in the paste, and would prevent the possibility of reducing it to a powder, which must be so fine as to pass through a thick gauze. It should be pounded in a cold place, and but a little while at a time, as after long beating the friction will in a degree soften the wax and gum, and .instead of their becoming a powder they will return to a paste. 11 Make strong gum arabic water, and when you paint, take a little of the powder, some colour, nnd mix them together with the gum water. Li^ht colours require but a small quantity of the powder, but more of it must be put in proportion to the body and 430 ENCAUSTIC PAINTING. darkness of the colours ; and to black there should be almost as much of ihe powder as colour. *• Having mixed the colours and no more than can be used before they grow dry, paint with fair water, as is practised in painting with water colours, a ground on the wood bein» first painted of some prop< r colour pr- pared in the same manner as is ('•• scribed for the picture; walnut- tree and oak are the sorts of wood com- monly made use of in Italy for this purpose. The painting should be very highly finished ; otherwise, when varnished, the tints will not appear united. " When the painting is quite dry, with rather a hard brush, pas. sing it one way, varnish it with white wax, which is put into an earthen vessel, and kept melted over a very slow fire till the pic. ture is varnished, taking great care that the wax does not boil. Afterwards hold the | icture before a fire, near enough to melt the wax, but not to make it run ; and when the varnish is entirely cold and hard, rub it gently with a linen cloth. Should the var- nish blister, warm the picture again very slowly, and the bubbles will subside. When the picture is dirty, it need only be washed with cold water." The opinion given by the society upon the above is. The me- thod made use of by Miss Greenland provides againt all inconve- niencies ; and the brilliancy of the colours in the picture painted by her, and exhibited to the society, fully justifies the opinion, that the art of puiuting in wax, as above described, highly merited the reward of a jjold pallet voted to her on this occasion. Another lady, Mrs. C. J. Hooker, of Ilottingdean, near Brigh- ton, laid before the Society of Arts, in 1807, the following method of preparing and applying a composition for painting in imitation of the ancient encaustic painting. •• Put into a glazed earthen vessel four ounces and a half of gum arabic, and eight ounces (or half a pint wine measure) of cold spring water ; when the gum is dissolved, stir in seven ounce-* of gum-mastich, which has been washed, dried, picked, and beaten fine. Set the < arthen vessel containing the gum-water, and gum. mastich, over a slow fire, continually stirring and beating them hard with a spoon, in order to dissolve the gum-mastich : when sufficiently boiled, it will no longer appear transparent, but will become opaque, and itili like a paste. As soon as this is the . KNCAUSTIC PAINTING. 431 fcnd the gum.water and mastich are quite boiling, without taking them off the fire, add five ounces of white wax, broktn into small pieces, stirring and beating the different ingredients to ;ether, till the wax is perfectly melted and has boiled. Then take the com- position off the fire, as boiling it longer than necess;iry would only harden the wax, and prevent its mixing so well afterwards with •water. When the composition is taken off the fire, and in the glazed earthen vessel, it should be beaten hard, and whilst hot (but not boiling) mix with it by degrees a pint (wine measure) or sixteen ounces more of cold spring water, then strain the romposi. tion, as some dirt will boil out of the gum. mastich. and put it into bottles : the composition, if properly made, should be like a cream, and the colours when mixed with it as smooth as with oil. The method of using it is to mix with the composition, upon an earthen palette, such colours in powder as are used in painting with oil, and such a quantity of the composition to be mixed with the co- lours as to render them of the usual consistency of oil colours ; then paint with fair water. The colours when mixed with the composition may be laid on either thick or thin, as may best suit your subject, on which account, this composition ~Is very advanta- geous, where any particular transparency of colouring is required, but in most cases it answers best, if the colours be laid tin thick, and they require the same use of the brush as if painting with body colours, and the same brushes as used in oil painting. The co. lours, if grown dry, when mixed with the composition, may be used by putting a little fair water over them : but it is less trouble to put some water when the colours are observed to be growing dry. In painting with this composition the colours blend without difficulty when wet, and even when dry the tints may easily be united by means of a brush and a very small quantity of fair water. When the painting is finished, put some white wax into a glazed earthen vessel over a slow fire, and when melted, but not boiling, with a hard brush cover the painting with the wax ; and when cold take a moderately hot iron, such as is used for ironing linen, and so cold as not to hiss if touched with any thing wet, and draw it lightly over the wax. The painting will appear as if under a cloud till the wax is perfectly cold, as also whatever the picture is painted upon is quite cold : but if, when so, the painting should not appear sufficiently clear, it may be held before the fire, so far from it as to melt the wax but slow/ : or the wax may bt 432 ENCAUSTIC PAINTING. molted by holding a hot pok« r at such a distance as to melt it gently, (-specially such puts of the picture as should not appear sufficiently transparent or brilliant : for the often- r he-it is applied to the picture, thf greater will b«* the transparency and brilliancy of colour'n; ; but the contrary etlect would be produced if too sudden or too great a degree of heat was applied, or for too long a time, as it would draw the wax too much to the surface, and might likewise crack the paint. Should tin- c<> t of wax put over the painting when finished appear in any part uneven, it may be remedied by drawing a moderately hot iron over it again as before mentioned, or even by scraping the wax with a knife : and should the wax by too great or too long an application of heat form into bubbles at particular places, by applying a poker heated, or even a tobacco-pipe made hot, the bubbles would subside ; or such de- fects may be removed by drawing any thing hard over the wax,- which would close any small cavities. *' When the picture is cold, rub it with a fine linen cloth. Paint- ings may be executed in this manner upon wood (having first pieces of wood let in behind, across the grain of the wood, to prevent its •warping) canvas, card, or plaster of Paris. The plaster of Paris would require no other preparation than mixing some fine plaster of Paris in powder with cold water the thickness of a cream ; tlu-n put it on a looking-glass, having first made a frame of bees. wax on a looking-glass the form and thickness you would wish the plaster of Paris to be of, and when dry take it off, and there will be a very smooth surface to paint upon. Wood and canvas are best covered with some gray tint mixed with the same composition of gum-arabic, gum-mastich, and wax, and of the same sort of colours as before mentioned, before the design is begun, in order to cover the grain of the wood or the threads of the canvas. Paintings may also be done in the same manner with only gum- water and gum-mastich, prepared the same way as the mastich and wax ; but instead of putting seven ounces of mastich, and w«ien boiling, adding five ounces of wax, mix twelve ounces of gum-mastich with the gum-water, prepared as mentioned in the first part of this receipt: before it is put on the fire, and when sufficiently boiled and beaten, and is a little cold, stir in by degrees twelve ounces, or three quarters of a pint (wine measure) of cold spring water, and afterwards strain it. It would be equally practicable painting with wax alone, dissolved in gum-water in flu PAINTING OF PAPER HANGINGS. 433 following manner. Take twelve ounces, or three quartos of a piut^ wine measure, of cold spring water, and four ounces and a half of gum-arabic ; put them into a glazed earthen vessel, and when the gum is dissolved, ad.l eight ounces of white wax. Put the earthen vessel with the gum-water and wax upon a slow fire, and stir them till the wax is dissolved and has boiled a few mi- nutes : (hen take them off the fire and throw them into a bason, as by remaining in the hot earthen vessel the wax would become rattier hard ; beat the gum-water and wax till quite cold. As there is but a small proportion of water in comparison to the quantity of gum ind wax, it would be necessary in mixing this composition with the colours, to put also some fair water. Should the compo. sition be so. .made as to occasion the ingredients to separate in the bottle, it will become equally serviceable if shaken before used to mix with the colours. '* I had lately an opportunity of discovering that the composi- tion which had remained in a bottle since the year 1792, in which time it ha-1 ^ro\vn dry and become as solid a substance as wax, re. turned to a cream-like consistence, and became again in as proper a state to mix with colours as when it was first made, by putting a little cold wati-r upon it, and suffering it to remain on a short time. I also lately found somt' of the mixture composed of only gum-arabic water and gum mastich, of which I sent a specimen to the Society of Arts in 1792 ; it was become dry, and had much the appearance and consistency of horn. I found, on letting some cold water remain over it, that it became as fit for painting with as when the composition wasfir^t prepared." [Caylus. Mantz. Pantolog. Transactions of the Society of Arts, Commerce, and Manufacture!. SECTION V. Painting of Paper Hangings. THERE are three methods of effecting this. The first by print, ing on the colours ; the second by using the stencil ; and iho third by lajing th«m on with a prncil, as in other kinds of painting. When the colours are laid on by printing, the impression is made by wooden prints, which are cut in such a manner that the figure to be expressed is made to project from the surface by cutting away VOL. vi. 2 P 454 PAINTING OF PAPER HANGINGS. all the other part ; and this, being charged with the colours tem- pered with their proper Tehicle, by letting it gently down on the block, on which the; colour is previously spread, conveys it from thence to the ground of the paper, on which it is made to fall more forcibly by means of its wefght, and the effort of the arm of the person who uses the print. It is easy to conclude that there must be as many separate prints as there are colours to be print* (1. But where there are more than one, great care must be taken, after the first, to let the print fall exactly in the same part of the paper as that which went before ; otherwise the figure of the design would be brought into irregularity and confusion. In common paper of low price, it is usual, therefore, to print only the outlines, and lay on the rest of the colours by stencilling, which both saves the ex. pence of cutting more prints, and can be practised by common workmen, nor requiring the great care and dexterity necessary to the using several prints. The manner of stencilling the colours is this : the figure, which all the parts of any particular colour make in the design to be painted, is to be cut out in a piece of thin lea. ther or oil. cloth, which pieces of leather, or oil. cloth, are called stencils ; and being laid flat on the sheets of paper to be printed, spread on a table or floor, are to be rubbed over with th« colour, properly tempered by means of a large brush. The colour passing over the whole, is consequently spread on those parts of the paper where the cloth or leather is cut away, and give the same effect at if laid on by a print. This is nevertheless only practicable in parts where there are only detached masses or spots of colours ; for where there are small continued lines, or parts that run one into another, it is difficult to preserve the connection or continuity of the parts of the cloth, or to keep the smaller corners close down to the paper ; and therefore, in such cases, prints are preferable. Stencilling is indeed a cheaper method of ridding coarse work than printing ; but without such extraordinary attention and trouble as render it fqually difficult with printing, it is far less beautiful and exact in the effect. For the outline of the spots of colour want that sharpness and regularity that are given by prints, besides the frequent extralincations, or deviations from the just figure, which happens by the original misplacing of the stencils, or the shifting the place of them during the operation. Pencilling is only used in the case of nicer work, such as the better imitations of the Indfa paper. It is performed in the same manner as other paint- PAINTING OF PAPER HANGINGS. 435 ings in water or varnish. It is sometimes used only to fill the out. lines already formed by printing, where the price of the colour, or the exactness of the manner in which it is required to be laid on, render the stencilling or printing it less proper ; at other times it is used for forming or delineating some parts of the design, where a spirit of freedom and vari ty, not to be had printed in out- lines, are desirable in the work. The paper designed tor receiv- ing the flock is first prepared with a varnish-ground with some proper colour, or by that of the paper itself. It is frequently practised to print some Mosaic, or other small running figure in colours, on the ground, before the flock be laid on; and it may be done with any pigment of the colour desired, tempered with var- nish, and laid on by a print cut correspondency to that end. The method of laying on the flock is this : a wooden print being cut, as is above described, for laying on the colour in such manner that the part of the design which is intended for the flock may project beyond the rest of the surface, the varnish is put on a block cover- ed with leather or oil-cloth, and the print is to be used also in the same manner, to lay the varnish on all the parts where the flock is to be fixed. The sheet, thus prepared by the varnished impres- sion, is then to be removed to another block, or table, and to be strewed over with flock, which is afterwards to be gently com- pressed by a board, or some other flat body, to make the varnish take the better hold of it : and then the sheet is to be hung on a frame till the varnish be perfectly dry, at which time the super- fluous part of flock is to be brushed off by a soft camel's-hair brush, and the proper flock will be found to adhere in a very strong manner. The method of preparing the flock is, by cutting woollen rags or pieces of cloth with the hand, by means of a large bill or chopping. knife ; or by means of a machine worked by a horse, mill. There is a kind of counterfeit nock-paper, which, when well managed, has very much the same effect to the eye as the real, though done with less expence. The manner of making this sort is, by laying a ground oi' varnish on the paper, and having after, wards printed the design of the flock in varnish, in the same man. ner as for the true ; instead of the flock, some pigment or dry colour, of the same hue with the flock required by the design, but somewhat of a darker shade, being well powdered, is strewed on th« printed varnish, and produces nearly the same appearance. 436 PAINTING OF PAPER HANGINGS. Mr. John Middletou lately communicated some improvements ia the printing of paper-hangings, to the Society of Arts. They are intended to facilitate the conveyance of the paper over the print- ing. table, and to give a greater pressure than usual to the block, when printing dark grounds. To facilitate the conveyance of the paper, two cords 36 feet long, are stretched from the printers table to the other end of the room, through rings, where they are kept tight by a weight ap. pended to their extremities. The paper to be printed is rolled up on a wooden roller at one side of the table, and its ends brought across the table, and fastened between two flat ledges that are con. nected at one end by an hinge, and at the other by a sliding ring ; these ledges slide along the two cords on pullies placed at each end of them, and serve to draw forward the paper as it is printed ; from the middle of these ledges a cord proceeds to the end of the room, between the other two cords, where it passes over a pulley, aud thence returns to a roller under the table ; the circle of this roller extends beyond the table, and there has a wheel fastened to it, from which projects three pins, each about four inches long, by , pressing on which with the foot, the wheel is turned round, and with it the roller ; by means of which, the paper is drawn forward on the cords a space corresponding to the distance between the pins in the wheel. The contrivance for giving an extraordinary pressure to the block, consists of a long and a short lever, projecting from one side of an axle, placed over head, above the printers' table, which levers and the matters supported by them, are balanced by a weight appended to an arm which proceeds from the other side of the axle ; from the long lever a cord falls to the ground, where a treadle is attach, ed to it : a long pole is jointed to the end of the short lever, and descends from it directly over the place of the block, on which it is made to press, by standing on the treadle whenever it is thought proper, and is put out of the way when not wanted, by placing the end of it behind a piece of wood, which projects upwards from the back of the table for that purpose. [Pantologia. CALICO-PRINTING; 4S7 Calico-printing. THIS ingenious art consists in dyeing cloth with certain colours and figures upon a ground of a different hue; the colours, when they will not take hold of the cloth readily, being fixed to them by means of intennedes, or mordants, as they were formerly called, constituting materials that have a chemical affinity or attraction for both the materials that form the colour, and the cloth to which the colour is to be applied. It was lung ago supposed that these inter, ruedos corroded their way into the interior of the cloth, and carried the colouring matter along with them, and it was on this account they were called mordants ; but since the science of che- mistry has been better studied and understood, it has been suili. ciently ascertained, that they only act or hold the dye and the cloth together, by a mutual affinity or attraction. The mordant which is principally used in the general process is a preparation of alum, called in the new nomenclature acetate of argil. It is prepared by dissolving 3lhs. of a'um and lib. of ace. tate of lead in 8lbs of w arm water. An exchange of the princi- ples of these salts takes place: the sulphuric acid of the alum combines with the oxide of lead, and the compound thus formed being insoluble, is precipitated, the acetic acid remains united with the argil of the alum in solution. There are added at the same time two ounces of the potash of commerce, and two ounces of chalk ; the principal use of which appears to be, to neutralize the excess of arid that might act on the colouring matter and alter its shade. The superiority of this acetate of argil as a mordant to the cheaper sulpliat of argil or alum, arises principally from two cir. cumstances ; from the affinity between its principles being weaker, in consequence of which, the argil more easily separates from the acid, and unites with the cloth and the colouring matter; and, 2dly, from the acetic arid disengaged in the process not acting with the same force on the colouring matter as the sulphuric acid would do. The acetate being also very soluble, and having little ten. deney to crystallize, can be more equally mixed and applied. The discovery of this mordant, so essential in the art of calico-printing, was altogether accidental, or rather empirical. The recipes of the calico-printers were at one time very complicated : different artiv Sri 438 CALICO-PRINTING. cles were from time to time omitted or changed, until at length the simple mixture of alum and acetate of lead was found to answer as a mordant, equally with compositions morn complicated. After the mordants have been applied, the cloth must be com- pletely dried. It is rroper for this purpose to employ artificial heat, which will contribute something -towards the separation of the acetous acid from its base, and towards its evaporation, by which the mordant will combine in a greater proportion, and more intimately with the cloth. When the cloth is sufficiently dried, it is to be washed with warm water and cow. dung, till all the flour, or gum, employed to thicken the mordants, and all those parts of the mordants which are un« combined with the cloth, are removed. The cow. dung serves to entangle these loose parts of the mordant?, and to prevent them from combining with those parts of the cloth which are to remain white. After this, the cloth is thoroughly rinsed in clean water. Almost the only dye-stuffs employed by calico-printers are in- digo, madder, and quercitron bark, or weld. This last substance, however, is but little used by the printers of (his country, except for delicate greenish yellows. The quercitron bark has almost superseded it, because it gives colours equally good, and is much cheaper and more convenient, not requiring so great a heat to fix it. Indigo, not requiring any mordant, is commonly applied at once, either with a block or a pencil. It is prepared by boiling together indigo and potash made caustic by quick lime, and orpi. nient; the solution is afterwards thickened with gum. It must be carefully secluded from the air, otherwise the indigo would soon be regenerated, which would render the solution useless. Dr. Bancroft has proposed to substitute coarse brown sugar for orpi- ment : it is equally efficacious in decomposing the indigo, and rendering it soluble ; while it likewise serves all the purposes of gum. Let us now give an example or two of the manner in which the printers give particular colours to calicoes. Some calicoes are only printed of one colour, others have two, others three or more, even to the number of eight, ten, or twelve. The smaller the number of colours, the fewer in general are the processes. 1. On • oi the most common colours on cotton prints is a kind of nankeen yellow, of various shades down to a deep yellowish brown, or drab. It is usually in stripes or spots. To produce it, CALICO-PRINTING. 43Q the printers besmear a block, cut out into the figure of the print, with acetic of iron, thickened with gum or flour ; and apply it to the cotton, which, after being dried and cleansed in the usual manner, is plunged into a potash ley. The quantity of acetite of iron is always proportioned to the depth of the shade. 2. For yellow, the block is besmeared with acetite of alumina. The cloth, after receiving this mordant, is dyed with quercitron bark, and then bleached. 3. Red is communicated by the same process ; only madder is substituted for the bark. 4. The tine light blues which appear so often on printed cottons, are produced by apply, ing to the cloth a block besmeared with a composition, consisting partly of wax, which covers all those parts of the cloth which are to remain white. The cloth is then died in a cold indigo vat ; and after it is dry, the wax composition is removed by hot water. 5. Lilac, flea brown, and blackish brown, are given by means of ace. tite of iron : the quantity of which is always proportioned to the depth of the shade. For very deep colours, a little sumach is added. The cotton is afterwards dyed in the usual manner with madder, and then bleached. 6. Dofe. colour and drab, by acetite of iron and quercitron bark. When different colour • are to appear in the same print, a greater number of operations are necessary. Two or more blocks are employed, upon each of which that part of the print only is cut, which is to be of some particular colour. These are besmeared with different mordants, and applied to the cloth, which is after- wards died as usual. Mr. Henry Maudeslay has a patent press for calico-printing : it is described in No. 54, Rep. of Arts, N. S., and No. 7, Retro* spect of Discoveries. In the towns of Manchester, Glasgow, Paisley, &c. many thou. sands of industrious hands are employed in the manufacture of this article; which, according to its different degrees of fineness, is sold from 6d. to 6s. and upwards a yard. Cotton cloth is an intermediate substance between that made of flax and animal wool; but by no means deserves to be commended as a substitute for flannel, next the skin. Calico imbibes and re. tains the perspired humours, unless it be as frequently changed as linen ; while flannel admits a free evaporation through its name* rous pores. [Bancroft. Chaptal. Gregory. Nicholson. 440 ENGRAVING. SECTION VII. Engraving. THIS curious and valuable art is for the most part of modern Invention, having its rise no »-;irlier than the middle of the fifteenth century. The ancients, ind»-od, practised engraving on precious stones and crystals with very good success; and there are still many of their vvorks remaining equal to any production of the lul< i ages. But the art of engraving on plates and blocks of wood, to afford prints or impressions, was not known till alter the intention of painting in oil. Of these last, the most ancient mode is that on wood, the first impressions on paper having been taken from carved wooden*blocks, For this invention we are indebted to the brief- malers, or makers of playing cards, who practised the art in Ger- many about the beginning of the fifteenth century. From the same source mav perhaps be traced the first idea of moveable types, which appeared not Ion?, after ; for these brief.malers ilid not en. tirely con§nu tlumselves to the printing and painting of cards, but produced also subjects of a more devout nature ; mam of which, takt n from lioiy writ, are still preserved in (German libraries, with the explanatory t"\t facing the figures, tue whole engraved in wood. Thus a species ot books was formed ; such as, Historia Sancti Jo- hannis, ejusque Visiones Aporaiypticae ; Historia Veteris et Novi Testament!, knov»n by the name of the Poor Man's Bible. These short mementos were printed only on one side ; aiul two of them being pasted together, h >d the appearance of a single leaf. The earliest date on any of these wooden cuts in 1423. The subject is St. Christopher carrying the infant Jesus over the sea, pre, served in a convent at Buxheim near Menningen. It is of a folio size, illuminated in the same manner as the playing cards; and at the bottom is this inscription, " Cristoferi faciem die quacunque tuerjs. Ilia nerope die morte mala non morieris. Millesimo CCCC° XX° tertio." Upon the invention of moveable types that branch of (he brief, malers business, so far as it regarded the making of books, was gradually discontinued; but tin art itself of engraving on wood continued in an improving state ; and towards tin.- end of the fif- ENGRAVING. 441 teenth century and the beginning of the sixteenth century, it be- came c istomary for almost every one of the German engravers on copper to engrave on wood also. The works of Albert Durer in this style of engraving are justly held in the highest esteem. Italy, France, and Holland, have produced many capital artists of this kind ; but for boldness and spirit we must see the prints of Christopher Jegher. who worked under the direction of Rubens, and was without doubt assisted by that great roaster. The in. vention of that species of engraving distinguished by the appella- tion of chiaro.scitro, seems also to be justly claimed by the Ger- mans, and first practised by Mair ; one of whose prints of this kind is dated 1499. Many excellent works in chiaro-scuro have been produced in France ; and in Italy it was honoured with the performances of Titian and Parmegiano, but the attempts of Jackson, Kirkall, and others in Knjand, have not been suc- cessful. A set of excellent prints in this way have lately been published by J. Skippe, esq. a connoisseur and dillettante. In Germany, about A. D. 1450, prints from engraved copper first made their appearance. The earliest date of a copperplate print is indeed only 1461 ; but however faulty this print may be with respect to the drawing, or defe tive in point of taste, the mecha- nical part of (he execution of it has by no means the appearance of being one of the fir«f productions of the.graver. We have also several gther engravings evidently the work of the same master; jn which the impressions are so neatly taken from the plates, and the engravings so clearly printed in every part, that according to all appearance, they could not be exeruted in a much better man- ner in the present day, with all the com', niom-ie- which the cop. perplate printers now possess, and the additional knowledge they must necessarily have acquired in the course of more than three centuries. Hence we may fairly conclude, that if they were not the first specimens of the engraver's workmanship, they were much less the first efforts of the copperplate printer's ability. It is likewise to be observed, that Martin Shoen, who is said to have worked from 1460 to i486', was apparently the scholar of Stoltz. for he followed his style of engraving, and copied from him a set of prints, representing the passion of our Saviour. Now, allowing Stoltzhirs to have preceded his disciple only ten years, this carries the era of the art back to 1450. as was said above. There is no ground to suppose that it wis known to the Italians 44'- ENGRAVING. till at least ten years afterwards. The earliest prints that ar« known to be theirs are a set of the seven plan* ts, and an almanac by way of frontispiece; on which are directions for finding faster from 1465 to 1517 inclusive : and we may be assured that tht- en- gravings were not antedated, as the almanac would have thus ireen lessvaluable. These prints must therefore have been executed in 146-4, which is only four years later than the Italians claim. The three earliest Italian engravers are Finiguerra, Boticelli, and Bal- dini. If we are to refer these prints to any of the three, we shall naturally conclude them to be the work of Finiguerra or Baldini ; for they are not equal either in drawing or composition to those ascribed to Boticeili, which we know at least were designed by him ; and as Baldini is expressly said to have worked from thp de. signs of Boticelli, it will appear most probable that they belong to Finiguerra. With respect to the invention of etching, it seems to be not well known to whom it is to be ascribed. One of the most early specimens is the print by Albert Durer, known by the name of th»» Cannon, dated 1518, and thought by some, with little foun- dation, to have been worked on a plate of iron. Another etching by the same artist is Moses receiving the tables of the law. dated 1524. It was also practised in Italy soon after this by Parme- giano, in whose etchings we discover the band of the artist work- ing out a system as it were from his own imagination, and striving to prodtice the forms he wanted to express. We see the difficulty he laboured under, and cannot doubt, from the examination of the mechanical p irt of the execution of his works, that he had no in- struction; and that it was something entirely new to him. If the story is true, that he kept an engraver by profession in his house, the novelty of the art is rendered so much the more probable. He died in 1540. As to that spccu-s of engraving in which the modes of etching and cutting with the graver are united, it must have been found necessary immediately upon the invention of etching ; it was, however, first carried to perfection by G. Audran, and is now al- most universally practised, whether tiie work is in strokes or in dots. Engraving in dots, the present fashionable method, is a very old invention, and the only mode discovered by the Italians. Agos. tino de Musis, commonly called Augustine of Venice, a pupil of Marc Antonio, used it in several of his earliest works, but confined it to the flesh, as in the undated print of an old man seated upon a bank, with a cottage in the back ground. He flourished from 1509 ENGRAVING. 443 to 1536. We also find it in a print of a single figure standing, holt' in;* a cnp an. I looking upwards, by Ginlio Canipagnolj, who engraved about the ye «r 15 1 6. Th»j back ground is executed with round d<»ts, made appari nlly with a dry point. The figure is out. lined with a stroke deeply engraved, and finished with dots, in a manner greatly resemb'ing those prints which Demarteau engraved at Paris in imitation of red chalk. The hair and beard are expres- sed by strokes. Stephen de Laulne, a native of Germany, fol. lowed the steps of Campagnola ; an»' his slight works are executed in dots only. John Boulan^er. a French artist, »vho flou- rished in the middle of the last century, and his contemporary Ni. cholas Van Plattenberg. improved greatly on this method, and prac- tised it with much success, ft is only, however, of late, that it has been considered as an obj- .t worthy of general imitation. John Lutma executed this kind of work with a hammer and a small punch or chisel. Engraving in mezzotinto was invented about the middle of the seventeenth century ; and the invention has gene* rally been attributed to prince Rupert. Engraving in aqua, tinta is quite a recent invention, and seems at once to have been carried to perfection by Sanriby, and other artists of the present age. Engraving with the tool was the kind originally prac. tised, and it is yet retained for many purposes. For though etching be more easy, and other advantage- attend it; yet where great retularity and exactness of the stroke or lines are required, the working with the graver is much more effectual : on which account it is more suitable to the precision necessary in the execution of portraits ; as there every thing the most .inure must be made out and expressed according to the ;.ri$!n.tl sub. ject, without any licence to the fancy of the designer in uVviar. ing from it, or varying the effect either by that masterly negl.^nce and simplicity in some parts, or tho?e hold sallies of the imugi. nation and hand in others, which give spirit and force to hisiory painting. Historical engravings for the port folio an^l furniture seemed at one period to advance rapidly towards perfection, to which the late alderman Boydell lately contributed ; but the death of Strange, Hall, and Woollet, have been almost fatal to the hopes of the ama. teur, which rest, in a great measure, upon Heath, Sharp, Bromley, and a few others, as in this particular instance we do not include 444 ENGRAVING. those eminent foreigners who hare, or do at present reside in England. Whatever deficiencies we may discover in the prosecu- tion of the arts in this country, is fortunately not to be attributed td want of genius, or relaxation from study in the artist ; the chill of apathy in the rich, who view a wretched coloured aquatint with the same or more pleasure than the most laboured production of the graver, is the baleful cause of the languishing state of historical en. graving. When persons capable of affording patronage .are taught discrimination, future Woollets will fascinate the best judges of engraving. We have, however, some very fine engravers, in dif. ferent departments, among whom it would be unjust not to specify the names of Milton, Scott, Lowry, and Mrs. Griffiths. [Wulpole. Phil. Trans. Pantoj. A very ingenious process has of late years been employed on the continent to answer at the same time both the purposes of de- signing and engraving ; or, in other words, to produce an engraving by the art of design4ng. This art or process is called (ithograpfy or stone-engraving: and among the German artists, who have recourse to it, chemische druckcry^ or chemical printing. From Germany it has spread into our own country, and still more lately into France and Italy. It consists in being first provided with a few small blocks of marble, about the size of Dutch tiles, or larger, according to the intended dimensions of the print; the thickness should be about two inches. The landscape, or other subject, is then to be traced over with a pencil ; and the pencil lines to be afterwards at leisure retraced with a particular ink which was at first a great secret. It is now, however, known to consist of a so- lution of lae in potash, coloured black by soot from burning wax. When the design has been gone over with this ink, it is left to dry, which commonly takes about two hours, though this will depend upon the temperature and dryness of the atmosphere. The face of the marble being, after this process, washed with nitric acid more or less diluted according to the degree of relief desired, the whole surface will be corroded except where defended by the resinous ink. The operation is now completed, and to obtain printed co- pies nothing more is necessary than to wash the marble clean ; to distribute over it, by means of printers.' balls, an ink similar to that commonly used by printers; and to press down upon the di. SCULPTURE. 445. sign, by a copper roller or copper-plate press, a sheet of paper pro. perly disposed in a frame. A few of such marble tiles or blocks are now frequently taken by travellers through picturesque scenery, who produce at one and the same time the drawing and the engraving, and the latter with far more correctness to the former than can possibly be obtained by copying And as soon as a sufficient number of prints have been, struck off, nothing more is necessary than to replane and repolish the marble tiles, when they will be immediately ready for other subjects. A particular account of this process, drawn up by M. Marcel de Serres, will be found in the Annales de Chemie, vol. Ixxii. [Editor. SECTION VIII. * Sculpture. ENGRAVING is occasionally called working en creux^ sculpture working in relievo : yet in its most comprehensive range the word sculpture has been applied to both these. The studies necessary for the young sculptor, towards the attain, ment of his art, are so similar to those which form the painter (with the obvious exceptions arising from the difference of materials em. ployed in the two arts), that very little remains here to be enlarged on, under the head of studies. The principal acquisitions to which the student must direct bis endeavours are, a knowledge of compo- sition, form (including anatomy), and expression ; to which, as in painting, must be added the difficult study of grace. The method of study most recommended to young sculptors is, to begin with copying, and to end with rivalling, the forms of the Greek statues. '* Vos exemplaria Graeca Nocturna versate manu, versate diurna ;" says Du Fresnoy : nor can it be questioned that the sculptors are, generally speaking, the safest guides to the study of nature. But it should not pass unnoticed, that although the forms of the Greek sculpture are, in general, not only more beautiful, but more appro, priately so than any other ; yet in some instances they hare bee» 446 SCULPTURE. surpassed by modern sculptors, us in the forms of infants by Fla- mingo. The- method of execution in the Greek stitues and other works of sculpture, seems to have been extremely different from that which is generally in use among modern artists. In the ancient statues, we frequently find striking proofs of the freedom and boldness that accompanied each stroke of the chisel, and which re. suited from the artist's beim; perfectly sure of the accuracy of the method which he pursued. Even in the most minute parts of the figure, no indication of timorousriess or diffidence appears: nothing that can induce us to believe, that the artist feared he might hare occasion to correct his strokes. It is difficult to find, even in the second-rate productions of the Grecian artists, any marks of a false or a random touch. This firmness and precision of the Grecian chisel were certainly derived from a more determined and perfect set of rules, than those of which we are masters. Besides studying, therefore, in the productions of the Grecian masters, their choice and expression of select nature, whether beautiful, sublime, or graceful, together with that sedate grandeur and simplicity which pervade all their works, the artist will do well to investigate the manual and mechanical part of their operations, as they may lead to the perception of their mode of progress. As soon as the artist has rendered himst If familiarly acquainted with the beauties of the Grecian statues, and formed his taste on the admirable models they exhibit, he may then proceed with ad* vantage and assurance to the imitation of nature. The ideas he has already formed of the perfection of nature, by observing her dispersed beauties combined and collected in the composition of the ancient artists, will enable him to acquire with facility, and to employ with advantage, the detached and partial ideas of beauty which will be exhibited to his view in a survey of nature, in her actual state. When he discovers these partial beauties, he will be capable of combining them with those perfect forms of beauty, with which he is already acquainted. In a word, by having always pre. sent to his mind the noble models already mentioned, he will form an accurate judgment of the powers of his art, and will draw rules from his own mind. There are, however, two ways of imitating nature. In the one, a single object occupies the artist, who endeavours to represent it with precision and truth ; in the other, certain Hues and features SCULPTURE. 447 are taken from a variety of objects, and combined and blended into one regular whole. All kinds of copies belong to the first kind of imitation ; and productions of this sort must necessarily be exe. cuted in a confined and servile manner, with high finishing, and little or no invention. But the second kind of imitation leads directly to the investigation and discovery of true beauty, of that beauty whose perfect idea is only to be found within the mind. Of the different modes of process in sculpture. — Works of of sculpture are performed, either by hollowing or excavating, as in metals, agates, and other precious stones, and in marbles of every description ; or by working in relief, as in bas-reliefs in the materials just mentioned, or in statues of metal, clay, wood, wax, marble, or stone. The excavation of precious stones forms a particular branch of art called intaglio, which, together with the working them in re- lievo, when the term camayeu is applied to them, belongs to the art of seal-engraving. The excavation of metals consitutes the art of engraving, in its various branches, on metal of any kind ; and its relief comprises enchasing, casting in bronze, &c. The process of hollowing hard stone or marble will need no par- ticular description ; especially as it is now wholly in disuse, ex. cept for the forming of letters in monumental or other inscriptions. In working in relief the process is necessarily different, accord. ing to the materials in which the work is performed. As not only the beginning of sculpture was in clay, for the pur- pose of forming statues, but as models are still made in clay or wax, for every work undertaken by the sculptor ; we shall first consider the method of modelling figures in clay or wax. Few tools are necessary for modelling in clay. The clay being placed on a stand or sculptor's easel, the artist begins the work with his hands, and puts the whole into form by the same means. The most expert practitioners of this art seldom use any other tool than their fingers, except in such small or sharp parts of their work as the fingers cannot reach. For these occasions, they are pro. vided with three or four small tools of wood, about seven or eight inches in length, which are rounded at one end, and at the other flat and shaped into a sort of claws. These tools are called by the French ebauchoirs. In some of these the claws are smooth, for the purpose of smoothing the surface of the model ; and in others art 448 SCULPTURE, made with teeth, to rake or scratch the clay, which is the first pro- cess of the tool on the uork, and in which state many parts of the model are frequently left by artists, to give an appearance of free, dom and skill to their work. If clay could be made to preserve its original moisture, it would undoubtedly be the fittest subtance for the models of the sculptor ; but when it is placed either in the fire, or left to dry imperceptibly in the air, its solid parts grow more compact, and the work shrinks, or loses a part of its dimensions. This diminution in size would be of no consequence, if it affected the whole work equally, so as to preserve its proportions. But this is not always the case: for the smaller parts of the figure drying sooner than the larger ; and thus losing more of their dimensions in the same space of time, than the latter do j the symmetry and proportions of the -work in. evitably suffer. This inconvenience, however, is obviated by forming the model first in clay, and moulding it in plaister of Paris before it begins to dry, and the taking a plaister cast from that mould, and the re. pairing it carefully from the original work ; by which means you have the exact counterpart of the model in its most perfect state ; and you have, besides, your clay at liberty for any other work. In order to model in wax, prepare the wax in the following man- ner : to a pound of wax add half a pound of scammony (some mix turpentine also), and melt the whole together with oil of olives; putting more or less oil as you would have your modelling wax harder or softer. Vermillion is sometimes mixed with this compo. sition, to give it a reddish colour, in imitation of flesh. In modelling in wax, the artist sometimes uses his fingers, and sometimes tools of the same sort as those described for modelling in clay. It is at first more difficult to model in wax than in clay, but practice will render it familiar and easy. Of the use of the model. — Whatever considerable work is un. dertaken by the sculptor, whether bas-relief, or statue, &c. it is al. ways requisite to form a previous model, of the same size as the intended work ; and the model being perfected, according to the method before described, whether it is in clay, or in wax, or a cast in plaister of Paris, becomes the rule, whereby the artist guides himself in the conduct of his work, and the standard from which he takes all its measurements. In order to regulate himself more correctly by it, he puts over the head of the model an immoveable SCULPTURE. 449 circle, divided into degrees, with a moveable rale fastened in the centre of the circle, and likewise divided into parts. From the extremity of the rule hangs a line with a lead, which directs him in taking all the points, which are to be transferred from the model to the marble ; and from the top of (he marble is hung also a line, tallying with that which is hung from the model } by the corre. spondence of which two lines, the points are ascertained in the marble . Many eminent sculptors prefer measurements taken br the com- passes to the method just described ; for this reason, that if the model is moved but ever so little from its level, the points are no longer the same. This method, however, offers the best means, by which mecha- nical precision may be attained j but it is manifest, that enough yet remains to exercise and display the genius and skill of the artist. For, first, as it is impossible, by the means of a straight line, to determine with precision the procedure of a curve, the artist de- rives from this method no certain rule to guide him, as often as the line which he is to describe deviates from the direction of the plumb, line. It is also evident, that this method affords no certain rule to determine exactly the proportion, which the various parts of the figure ought to bear to each other considered in their mutual rela- tion and connections. This defect, indeed, may be partly supplied by intersecting the plumb-lines by horizontal ones ; bnt even this resource has its inconveniences ; since the squares formed by trans- versal lines that are at a distance from the figure (though they are exactly equal), yet represent the parts of the figure as greater or smaller, according as they are more or less removed from our point of view. Of sculpture in -csood. — A sculptor in wood should first take care to choose wood of the best quality, and the most proper for the work which he intends to execute. If he undertakes a large • work, requiring strength and solidity, he ought to choose the hardest wood, and that which keeps best, as oak and chesnut ; bat for works of moderate size, pear or apple-tree serve very well. As even these latter wooils are still of considerable hardness, if the work i-0'isi-.ts only of delicate ornaments, the artist will find it preferable to take some more tender wood, provided it is at the same time firm and ciose ; as, for instance, th« Indian tree, which rot. vx. ?a 45O is excellent fur this purpose, as the chisel cuts it more neatly ami easily than any other wood. The ancients made statues out of almost every different kind of wood. At Sicyon was a statue of Apollo made of box ; the statue of Diana at Fphesus was of cedar. As these two sorts of wood are extremely hard and undecaying ; and as cedar, in particular, is of such a nature, as, according to Pliny, to be nearly indestructible, the ancients preferred them for the images of their divinities. In the temple built on mount Cyllcne in honour of Mercury, Pausanias relates, that there was a statue of that god made of citron- wood, eight feet in height. This wood was also much esteemed. The cypress likewise, being a wood not apt to spoil, nor to be damaged by worms, was also used for statues ; as were the palm- tree, olive, and ebony, of which latter, according to Pliny's ac- count, there was another statue of Diana at Ephesus. Several other kinds of wood were equally employed for this purpose, even the vine, of which the same author says there were •tatues of Jupiter, Juno, and Diana. Felibien speaks of a French artist at Florence, of the name of Janni, who executed several statues in wood, in a style of finishing equal to maible, and particularly one of St. Rocque, which Vasaii considered as a marvellous production. The beauty of sculpture in wood consists in the tender manner of cutting the wood, free from all appearance of hardness or dryness. For any work of large dimensions, even though it consists of a single figure; it is better to join together several smaller pieces of wood than to make the whole of a single large piece; which is more liable to warp and crack, on account of its not being always dry at heart, although it appears perfectly dry on the outside. No wood can be properly fit for works of this kind that has not beeu cut at least ten years before. The tools used for sculpture in wood are the same as those of the joiner or cabinet-maker. Of sculpture in stone and marble. — For sculpture in marble and other stone, the artist must make use of tools made of good steel, well tempered, and of strength proportioned to the hardness of the material. SCULPTURE. 451 The first thing to be done is, to saw out from a larger block of marble, a block proportioned to the size of the work which is un- dertaken. After this, the sculptor shapes the gross masses of the forms he designs to represent, by knocking off the superfluous par(s of marble with a strong mallet or beel, and a strong steel tool called a point. When the block is thus hewn out agreeably to the measures pre- riously tak'>n for the performance of the work, the sculptor brings it nearer to the intended form by means of a finer point ; and some, times of a tool called a dog's tooth, having two points, but less sharp than the single one. After this he uses the gradine, which is a flat cutting tool, with three teeth, but is not so strong as the point. Having advanced his work with the gradine, he usesthe chisel to take off the ridges left by the former tools ; and by the dexte- rous and delicate use of (his instrument, he gives softness and ten. derness to the figure, till at length, by taking a rasp, which is a sort of a file, he brings his work into a proper state for being po. lished. Rasps are of several kinds, some straight, some curved, and some harder or softer than others. When the sculptor has thus far finished his work with the best tools he can procure, wherever certain parts or particular works require polishing, he uses pumice-stone to make all the parts smooth and even. He then goes over them with tripoli, and when he would give a still higher gloss, he rubs them with leather and straw- ashes. Besides the tools already mentioned, sculptors use also the pick, which is a small hammer pointed at one end, and at the other formed with teeth made of good steel and squared, to render them the stronger. This serves to break the marble, and is used in all places where the two hands cannot be employed to manage the mallet and chisel. The bouchard, which is a piece of iron, well steeled at the bot- tom, and formed into several strong and short points like a dia- mond, is used for making a hole of equal dimensions, which cannot be done with cutting tools. The bouchard is driven with the mal- let or beetle, and its points bruise the marble and reduce it to powder. Water is thrown into the hole from time to time, in pro. portion to the depth that is made, to bring out the dust of the 3cf* 452 POTTERY AND PORCELAIN. marble, and to prevent the tool from heating, which would destroy its temper ; for the free.stone ilust on which tools are edged, is only moistened with water to prevent the iron from heating and taking off the temper of the tool by being rubbed dry ; and the trepans are wetted for the same reason. The sculptor uses the bouchard to bore or pierce such parts of his work as the chisel cannot reach without danger of spoiling or breaking them. In using it, he passes it through a piece of lea. ther, which leather covers the hole made by the bouchard, and pre- Yt/nfs the water from spirting up in his face. The tools necessary for sculpture on marble or stone, are the roundel, which is a sort of rounded chisel; the houguet, which is a chisel squared and pointed ; and various compasses to take the requisite measures. The process of sculpture in stone is the same as in marble, ex. cepting that the material being less hard than marble, the tools used are not so strong, and some of them are of a different form, as the rasp, the hand- saw, the ripe, the straight chisel with three teeth, the roundel, and the grater. If the work is executed in free.stone, tools are employed which are made on purpose, as the free-stone is apt to scale, and does not work like hard stone or marble. Sculptors in stone have commonly a bowl in which they keep a powder composed of plaister of Paris, mixed with the same stone in which their work is executed. With this composition they fill up the small holes, and repair the defects which they meet with in the stone itself. [IValpole. Winckelmann. Du Fresnoy. Pantalog. SECTION VIII. Pottiry and Porcelain. PORCELAIN may be regarded as the finest kind of pottory ; the art of which consists in working and moulding plastic earths, more or less simple into hard brittle vessels of various kinds and forms, an quite a distinctive charactt r between porcelain and pottery, for the fracture of pot. tery is extremely granular : and hence porcelain may correctly be regarded as a substance of a middle nature between pottery and glass. From these circumstances it appears probable that no chemical action takes place in any pottery combination till it arrives at the state of porcelain. The most perfect and b-auiilul porcelains of Japan in China are composed of two distinct earths ; one in which silex predominates, and which units in a strong fire ; and another which is infusible per se : and by the union of those two earths a porcelain is product d which scarcely vitrifies at the utmost furnace heat which art can excite. This substance possesses ti>e combined exce'lHieies of ^reat hardness, beautiful semi. transparency, exqui- site whiteness, where not artificially coloured, strong fou_ and cohesion ; so that it has strength enough for the purposes for •whit h ii is designed when n.ade very thin, and bears sudden heat- ing and coo'ing without cracking. Of V beautiful European porcelains which have been made in imitation of tin- oriental, it does not appear that any of them unite all iis excellencies. Earthy combinations have been made «qua ly strong, tough, an.) in.u ible,and as truly porceluincous when burnt, but they have not quite rivalled the best Japanese in delicate POTTERY AND PORCELAIN. 455 whiteness and lustre. As these last qualities, howerer, are es. teemed most essenthl. that of infusihility (which indeed is of no great consequence for any of the common uses of porcelain) hai been sacrificed ; and hence those that make a near approach to the oriental in beauty and delicate lustre, of which many manufac- tures in different parts of Europe have afforded splendid examples, are frequently found to suften and melt down in an intense heat of a wind-furnaie, at which the true Nankin and Japun china undergo no change. The manufacture of the ordinary pottery is on the whole very simple where a due selection of materials is made ; but the orna- mental branches of it, such as those of modelling, enamelling, painting, and gilding, which often display exquisite beauty, are accompanied with much delicacy, and require a combination of perseverance, skill, and practical nicety of management, that are rarely equalled in any other chemical manufacture. An intimate mixture of the ingredients used in pottery is of great importance to the beauty, compactness, and soundness of the ware. Formerly the wet clay and ground flint, or whatever else was employed, were beaten together with long continued manual labour, no more water being added than was necessary to render the clay thoroughly plastic. This laborious and expensive method has now been laid aside in the larger potteries ; and the ingenious method has been substituted of bringing each material first to an impalpable powder, and diffusing them separately in as much wa- ter as will bring them to the consistence of thick cream, mixing them in due proportion by measure, and when thoroughly stirred together, evaporating the superfluous water till the mass is brought to a proper consistence for working. In the Staffordshire process the materials are a fine clay, brought chiefly from Devonshire, and a siliceous stone called chert, or else common flint reduced to p.owder by heating it red-hot, quenching it in water, and then grinding it by windmills. Kach material is passed through fine brass sieves, then diffused in water, mixed by measure, and brought to a plastic state as above. The wheel and lathe are the chief, and almost the only, instru- ments made use of : the first for large works, and the last for small. The potter's wheel consists principally in the nut, which is a beam or axis, whose foot or pivot plays perpendicularly oo a free-ston esole or bottom. From the four corners of this beam, 456 POTTERY AND PORCELAIN. which does not exceed two feet in height, arise four iron bars, called the spokes of the wheel ; which, forming diagonal lines with the beam, descend, and are fastened at bottom to the edges of a strong wooden circle, four feet in diameter, perfectly like the fel- loes of a coach-wheel, except that it has neither axis nor radii, and is onlj joined to the beam, which serves it as an axis, by the iron bars. The top of the nut is flat, of a circular figure, and a fool in diameter : and on this is laid the clay which is to be turned and fashioned. The wheel, thus disposed, is encompassed with four Bides of four different pieces of wood fastened on a wooden frame; the hind- piece, which is that on which the workman sits, is made a little inclining towards the wheel ; on the fore.piece are placed the prepared earth ; on the side.pieces he rests his feet, and these are made inclining, to give him more or less room. Having pre. pared the earth, the potter lays a round piece of it on the circular head of the nut, and sitting down, turns the wheel with his feet till it has got the proper Telocity ; then, wetting his bands with wa. ter, he presses his fist or his finger-ends into the middle of the lump, and thus forms the cavity of the vessel, continuing to widen it from the middle ; and thus turning the inside into form with one hand, while he proportions the outside with the other, the wheel constantly turning all the while, and he wetting his hands from time to time. When the vessel is too thick, he uses a flat piece of iron, somewhat sharp on the edge, to pare off what is redundant; and when it is finished, it is taken off from the circular head, by a wire passed underneath the vessel. The potter's lathe is also a kind of wheel, but more simple and slight than the former, its three chief members are an iron beam or axis three feet and a half high, and two feet and a half diameter, placed horizontally at the top of the beam, and serving to form the vessel upon : and another large wooden wheel, all of a piece, three inches thick, and two or three feet broad, fastened to the same beam at the bottom, and parallel to the horizon. The beam or axis turns by a pivot at the bottom in an iron stand. The work, man gives the motion to the lathe with his feet, by pushing the gwat wheel alternately with each foot, still giving it a greater or lesser degree of motion, as his work requires. They work with the lathe, with the same instruments, and after the same manner, as with the wh«el. The mouldings are formed by holding a piece1 qf wood or iron, cut in the form of the moulding, to the vessel, POTTERY AND PORCELAIN. 457 while the wheel is turning round, but the feet and handles are made by themselves, and sot on with the hand ; and if (here be any sculpture in the work, it is usually done in wooden moulds, and stuck on piece by piece on the outside of the vessel. Handles, spouts, &c. are afterwards fixed on to the moulded piece if required ; and it is then set to dry for some days in a warm room, where it becomes so bard as to bear handling without altering its shape. When dry enough it is inclosed along with many others in baked clay cases of the shape of bandboxes, called seggars, which are made of the coarse clays of the country. These are next ranged in the kiln or furnace so as to fill it except a space in the middle for the fuel. Here the ware is baked till it has remained fully red hot for a considerable time, which in the larger kilns consumes ten or fifteen tons of coals: after which the fire is allowed to 'go out, and when all is cooled, the seggars are taken out, and their contents unpacked. The ware is now in a state of biscuit, perfectly void of gloss, and resembling a clean egg-shell. In order to glaze it, which is the next process, the biscuit ware is dipped in a tub containing a mixture of about sixty parts of litharge, ten of clay, and twenty of ground flint, diffused in water to a creamy consistence, and when taken out, enough adheres to the piece to give an uniform glazing, when again heated ; for which pnrpose the pieces are re. packed up in the seggars, with small bits of pottery interposed between each, and fixed in the kiln as before. The glazing mix- ture fuses at a very moderate heat, and gives an uniform glossy coating, which finishes the process for common white ware j though the painting and gilding require subsequent attention. [Pantologia. D'Entrecollet. Letlres Edifiuntet et Curieuses. C 458 ] CHAP. IV. BURNING M1URORS. 1 HE fertile genius of Archimedes illustriously appears, not only in those works of his w hieh have been handed down to us, but also in the admirable inscriptions which the authors of his time have given us of his discoveries in mathematics and mechanics. Some of the inventions of this great man have appeared so far to surpass human ability and imagination, that some celebrated philosophers have called them in question *, and even gone so far as to pretend to prove their impossibility, The following pages will produce many proofs of what is here advanced : meanwhile, our present ob- ject is to examine into the subject of the burning glasses, employed by Archimedes to set fire to the Roman licet at the siege of Syra- cuse. Kepler, Naudeus, and Descartes, have treated it as a mere fable, though the reality of it hath been attested by Diodorus Sicu- lus, Lucian, Dion, Zonaras, Galen, Anthemius, Eustathius, Tzet- zrs, and others. N.iy, some have even pretended to demonstrate by the rules of catoptrics the impohsibility of it, notwithstanding the asseveration of such respectable authors, whose testimony eught to have prevented them from rejecting so lightly a fact so well supported. Yet all modern enquiries have not been involved in this mistake. Father Kircher, attentively observing the description which Tzetzes gives of the burning glasses of Archimedes, resolved to prove the possibility of this; and having, by means of a number of plain mirrors, collected the sun's rays into one focus, he so augmented f • Descartes in his Dioptrics, Discourse 8th, p. 128. Fontcm lie, and many other. + Kirrhrr, dc Ante Mi'gua Locis, ct Umbrae, lib. 10, p. 3. p. 874 nd tint in, et Problem. 4, 3a part, de MagiA Catoptrica— And p. 884, 887, he delivers the catoptric rulr<. for making burning glasses l>\ a proper disposition of many phiin mirrors. And in p. 88, relates an experiment of his own, whereby he pro- duced a lip.il ini • DM- enough to burn, by means of five mirrors directing the rajs of the sun into one focus; he supposes that I'roclu-. by such means might set fire to Vitdlios'g fleet, and invites tlic kkilful to bring this assay to perfection. BURNING MIRRORS. 45Q tbe solar heat, that at last by encreasing the number of mirrors, he coul I produce the ir.ost intense degree of it. Tzc'zes's description of the tjla^s Archimedes made use of, is indeed very proper to raise such an idea as Kircber enter'ained. That author .-ays, 'hat Archimedes set fire to Marceilus's navy, by means ,jf n }>\\\ ningqlass composed of snmll square mirror*, moving every way up.»n ranges ; which, when placed in the sun's rays, di- rected them upon the Roman fleet, so as to reduc* it to ashes at the distance of a how. shot. It is probable Mr. J)e Bulfon availed him. self of this description, in constructing his burning glass, composed of 168 little plain mirrors, which produced so considerable a heat, as to set wood in flame- at the distance of two hundred and nine feet ; melt lead, at that of one hundred and twenty ; and silver, at that of fifty. Another testimony occurs, which loaves not the least doubt in this case, but resolves all in favour of Archimedes. Anthemuis of Trall«-s, in L> ed to the .-un, transmit a heat suth'ci'-nt to s»n fire to cloth or corrode away the dead flesh of those patients who stand in need of caustics ; and the latter, after Clemens Alexandrinus, takes notice fhat fire may be kindled, by int. rposing glasses filled with water, between tho sun and the object, so as to transmit the rays to it. [Dutens. Among the moderns one of the earliest who devised a burning mirror, was the celebrated Lord Napier, the in?entor of logarithms, who, in a paper containing hints of secret inventions, dated June 2, 1596, (the original of which is now among the MSS. in the Lambeth library, marked 658, anno 1596), says, " First, The invmtion, proof, and perfect demonstration, geo- metrical and algebraical, of a burning mirror, which receiving of dispersed brains of the sun, doth reflex the same beams altogether unift d, and concurring precisely in one mathematical point, in the which point, most necessarily it engendereth fire ; with an evident demonstration of their error who affirm this to be made a parabolic •ection. The use of this invention serveth for the burning of the enemy's ships at whatsoever appointed distance. " Secondly, The invention and sure demonstration of another mirror, which receiving the dispersed beams of any material fire, or flame, yieldeth also the former effect, and serveth for the like use." Of the moderns, the most remarkable burning-glasses, are those of Magine of 20 inches diameter ; of Sepatala of Milan, luar 42 inches diameter, and which burnt at the distance of 15 feet ; of Settala, of Vilette, of Tchirnhausen, of Buffbn, of Trudaine, and of Parker. That of M. de Villette was three feet eleven inches in diameter, and its focal dis'ance was three f«-et two inches. Its substance is a composition of tin, copper, and tin. glass. Some of its effects, as found by Dr. Harris and Dr. Desaguliers, are, that a silver six. pence melted in 7{"j a King fieorge's halfpenny melted in 16", and i-.n in 34"; fin melted in 3", and a diamond weighing 4 grains, lo*f J'lis of its we;£ht. 1 .:.it of M. de Hnllbn is a polyhedron, six feet broad, and as many high, consisting of itib small mirrours}or flat pieces of look. BURNING GLASS, 463 ing.glass, each six inclips square ; by means of which, with the faint rays of the sun in the month of March, he set on fire boards of beech wood at 150 feet distance. Besides, his machine has the conveniency of burning downwards, or horizontally, as one pleases ; each speculum being moveable, so as, by the means of three screws, to be set to a proper inclination for directing the rays towards any given point ; and it turns either in its greater focus, or in any nearer interval, which our common burning-glasses cannot do, their focus being fixed and determined. M. de Bnffon, at another time, burnt wood at the distance of 200 feet. He also melted tin and lead at the distance of above 120 feet, and silver at 50. Mr. Parker, of Fleet. street, London, was induced, at an ex. pence of upwards of 7001. to contrive, and at length to complete a large transparent lens, that would serve the purpose of fusing and vitrifying such substances as resist the fires of ordinary fur- naces, and more especially of applying heat in vacuo, and in other circumstances in which it cannot be applied by any other means. After directing his attention for several years to this object, and performing a great variety of experiments in the prosecution of it, he at last succeeded in the construction of a lens, of flint-glass, three feet in diameter, which, when fixed in its frame^ exposes a surface of 32 inches in the clear ; the distance of the focus is 6 feet 8 inches, and its diameter 1 inch. The rays from this large lens are received and transmitted through a smaller, of 13 inches diameter, in the clear within the frame, its focal length 29 inches, and diameter of its focus |ths of an inch : so that this second lens increases the power of the former more than 7 times, or as the square of 8 to the square of 3. From a great number of experiments made with this lens, the following are selected to serve as specimens of its powers : Substances fused ; tcit/i their tceight, and iimt of fusion. Time in sec. in grs. Scoria of wrought iron . . . 2 12 Common slate . . ... 2 10 Silver, pure ... . 3 20 Platina, pure .... 3 10 Nickel . .... 3 16 Cast iron, a cube . . . . . 3 10 404 BURNING GLASS. Substances fused ; teith their weight, and lime of fusion. Time Wgt. in sec. in ;i-. K.earch . . . . . 3 1C Gold, pure . . ... 4 20 Crystal pebble .... 6 '7 ('auk, or terra ponderosa 7 10 Lava .... 7 10 Asbestos . . . 10 10 Bar iron, a cube ... 12 10 Steel, a cube . . . 12 10 Garnet . . . 17 K) Copper, pure . . . 20 33 Onyx . . . 23 10 Zeolites .... 23 10 Pumice stone . ... 24 10 Oriental emerald . 25 2 Jasper . . . . 25 10 White agate . . ... 30 10 Flint, oriental . . . . 30 10 Topaz, or chrysolite 45 3 L/ommon limestone . 55 10 White rhomboidal spar 60 10 Volcanic clay . . . 60 10 furnish moorstone . . . 60 10 tough cornelian . . . 75 10 Rotten stone . .... 80 10 What is remarkable with regard to experiments on iron, is, that the lower part, i. e. tiiat part in contact with the charcoal, was first melted, when thai part which was exposed to the focus re- mained unfused : an evidence of the effect of (lux on this metal. Several of the semi.crystalline substances, exposed to the focal heat, exhibited symptoms of fusion : such as the agate, oriental flint, cornelian, and jasper ; but as the probability is, that these substances were not capable of complete vitrification, it is enough that they were rendered externally of a glassy form. Garnet completely fused on black-lead in 120", lost |th of a grain, became darker in colour, and was attracted by the magnet. Ten cut gar. nets taken from a bracelet, began to run the one into the other in a few seconds, and at last formed into one globular garnet. The flay used by Mr. Wedgwoo'l, to make his pyrometric test, run in a few seconds into a white enamel. Seven olher kinds of clay seat by Mr. Wedgwood, were all vitrified. Several experiment* ;. SECT : ARCHITECTURE AND MECHANICAL SCIENCpS. 465 were made on limestone, some of which were vitrified, hut all of which were agglutinated ; it is, however, suspected that some ex- traneous substance must have been intermixed. A globule pro- duced from one of the specimens, on bring put into the mouth, flew into a thousand pieces, occasioned, it is presumed, by the moisture. [Pantologia. CHAP. V. GEKERAL ARCHITECTURE AND MECHANICAL SCIENCES. SECTION 1. Architecture and Mechanical Sciences of the Ancients. ARCHIMEDES alone would afford sufficient matter for a volume, in giving a detail of the marvellous discoveries of a genius so profound, and fertile in invention. We have seen in the" pre- ceding chapters, that some of his discoveries appeared so much above the reach of men, that many of the learned of our days found it more easy to call them in doubt, than even to imagine the means whereby he had acquired them. We are again going to produce proofs of the fecundity of genius belonging to this cele- brated man ; and in how high a degree of excellence he possessed this inventive faculty, may easily be judged of by the greatness of those events which were effected by it. Leibnitz, who was one of the greatest mathematicians of his age, did justice to the genius of Archimedes when he said, that if we were better acquainted with the admirable productions of that great man, we would throw away much less of our applause on the discoveries of eminent moderus. Wallis also, in speaking of Archimedes, calls him a man of admirable sagacity, who laid the foundation of almost all those inventions, which our age glories in having brought to perfection. In reality, what a glorious light hath he diffused over the mathe. matics, in his attempt to square the circle ; and in discovering the square of the parabola, the properties of spiral lines, the propor. TOL. VI. 2 If 406 ARCHITECTURE AND MliCHANlCAL SCIENCES, lion of the sphere to the cylinder, and the true principles of static* and hydrostatics ? What a proof of his sagacity did he gire in dis- covering the quantity of silver, that was mixed along with the gold, in the crown of King Hierem ; whilst he reasoned upon that prin- ciple, that all bodies immersed in water, lose just so much of their weight, as a quantity of Water equal to them in bulk weighs ? Hence he drew this consequence, that gold being more compact, must lose less of its weight, and silver more ; and that a mingled, mass of both, must lose in proportion to the quantities mingled. Weighing therefore the crown in water and in air, and two masses, the one of gold, the other of silver, equal in weight to the crown ; he thence determined what each lost of their weight, and so re. solved the problem. He likewise invented a perpetual screw, valuable on account of its being capable to overcome any resist- ance ; and the screw, that still goes by his own name, used in ele- vating of water. He, of himself alone, defended the city of Syracuse, by opposing to the efforts of a Roman general, the re. sources he found in his own genius. By means of many various •warlike machines, all of his own construction, he rendered Syra. cuse inaccessible to the enemy. Sometimes he hurled upon their land. forces stones of such an enormous size, as crushed whole bodies of them at once, and put the whole army into confusion. And when they retired from the walls, he still found means to annoy them ; for with catapults and balistaj, he overwhelmed them •with arrows innumerable, and beams of a prodigious weight. If their \essels approached the fort, he seized them by the prows with grapples of iron, which he let down upon them from the wall, and rearing them up in the air, to the great astonishment of every body, shook them with such violence, as either to break them in pieces, or sink them to the bottom. And when the Romans thought of sheltering themselves from his pursuit, by keeping at a distance from the haven, he borrowed fire from heaven, and aided by his own ingenuity, wrapped them in sudden and inevitable con. flagration, as we have seen in a preceding chapter. The superior knowledge he had in sciences, and his confidence in the powers of mechanism, prompted him once to say to King Hi» ron, who was his patron, admirer and friend ; give me but some other place to stand upon, and I'll set the earth itself in motion : and when the king, amazed at what he had said, seemed to be in hesitation : he gave him a striking proof of the possibility of what ARCHITECTURE AND MECHANIC AL SCIENCES. 467 he had advanced, by launching singly by himself a ship of a prodi. gious size. He built likewise for the king an immense galley, of twenty banks of oars, containing spacious apartments, gardens, walks, ponds, and all other conveniences suitable to the dignity of a great King. He constructed also a sphere, representing the motions of the stars, which Cicero esteemed one of the inventions •which did the highest honour to human genius. He perfected the manner of augmenting the mechanic powers by the multiplication of wheels and pullies ; and, in short, carried mechanics so far, that the works he produced of this kind, even surpass imagination. Nor was Archimedes the only one who succeeded in mechanics. The immense machines, and of such astonishing force, as were those which the art of the ancients adapted to the purposes of war, are a proof they came nothing behind us in this respect. It is with difficulty we can conceive how they reared those bulky moving towers, an hundred aud fifty .two feet in heighth, and sixty in com. pass, ascending by many stories, having at bottom a battering ram, a machine of strength sufficient to beat down walls ; in the middle a draw. bridge, to be let down upon the wall of the city attacked, in order to open a passage into the town for the assailants ; and at top a body of men, who, being placed above the besieged, harrassed them without running any risk. An ancient historian hath trans, mitted to us an action of an engineer at Alexandria, which deserves a place here. In defending that city against the army of Julius Caesar, who attacked it, he by means of wheels, pump>, and other machines, drew from the sea a prodigious quantity of water, which he afterwards turned upon the adverse army to their extreme annoy- ance. In short, the art of war gave occasion for a great number of proofs of this kind, which cannot but excite in us the highest idea of the enterprising genius of the ancients, and the vigour with which they put their designs in execution. The invention of pumps by Ctesibius ; and that of water-clocks, automatical figures, wind, machines, cranes, &c. by Heron, who lived in the second century; and the other discoveries of the Grecian geometricians, are so very numerous, that it would exceed the limits of a chapter, eyen to mention them. Should we pass to other considerations, we shall find equally in. conlestable evidences of greatness of genius among the ancients, in the difficult, and indeed astonishing enterprizes. in uhich they so successfully engaged. Egypt and Palestine still present us with Sftfl 468 ARCHITECTURE AND MECHANICAL SCIENCES. proofs of this, (he one in its pyramids, the other in the ruins of Palmyra and Balbrc*. Italy is filled with monuments, and the ruins of monuments, which aid us in comprehending the former magnificence of that people ; and ancient Rome even now attract! much more of our admiration than the modern. The greatest cities of Europe gi?e but a faint idea of that gran- deur, which all historians unanimously ascribe to the famous city of Babylon, which being fifteen leagues in circumference, was en- compassed with walls two hundred feet in height, and fifty in breadth, whose sides were adorned with gardens of a prodigious extent, which arose in terasses one above another, to the very summit of the walls ; and for the watering of those gardens they had contrived machines, which raised the water of the Euphrates to the very highest of those terrasses ; a height equalling that to •which the water is carried by the machine of Marly. The tower of Belus, arising out of the middle of a temple, was of so vast a height, that some ancient authors have not ventured to assign the measure of it ; others put it at a thousand paces. Ecbatane, the capital of Media, was of immense magnificence, being eight leagues in circumference, and surrounded with seven •walls, in form of an amphitheatre, the battlements of which were of. various colours, white, black, scarlet, bine, and orange ; but all of them covered with silver or with gold. Persepolis was also a dty, which all historians speak of as one of the most ancient and noble of Asia. There remain the ruins of one of its palaces, which measured six hundred paces in front, and still displays th« relics of its ancient grandeur. The lake of Mrcris is likewise a striking proof of the vast un- dertakings of the ancients. All historians agree in giving it above an hundred and fifty leagues in circuit; yet was it entirely the work of one Egyptian king, who caused that immense compass of ground to be hollowed, to receive the waters of the Nile, when it overflowed more than ordinary, and to serve as a reservoir for Catering Egypt by means of its canals, when the overflowing of the river was not of height sufficient to enrich the country. Out of the midst of this Lake, arose two pyramids, of about six hun. dred feet in height. * It is proper to remark tliat tin- temples and immense palaces of Palmyra, wliose magnificence Mirpasso all other buildings in the world, appear to have been built at the lime wbeii architecture was in its decline. ARCHITECTURE AND MBCHANICAL SCIENCES. 4&9 The other pyramids of Egypt, in their largeness and solidity, so far surpass whatever we know of edifices, that we should be ready to doubt of the reality of their having ever existed, did they not still subsist to this day. Mr. de Chezele, of the Academy of Sciences, who travelled into Egypt to measure them, assigns to one of the sides of the base of the highest pyramid, a length of six hundred and sixty feet, which reduced to its perpendicu. lar altitude, makes four hundred sixty and six feet. The free- stones, of which it is composed, are each of them thirty feet long; so that we cannot imagine how the Egyptians found means to rear such heavy masses to so prodigious a height. The Colossus of Rhodes was another of the marvellous produc- tions of the ancients. To give an idea of its excessive bigness, it need only be observed, that the fingers of it were as large as sta- tues, and very few were able, with outstretched arms, to encom- pass the thumb*. In short, what shall we say of the other structures of the anci- ents, which still remain to be spoken of? Of their cement, which in hardness equalled even marble itself ; of the firmness of their highways, some of which were paved with large blocks of black marble ; and of their bridges, some of which still subsist irrefra. gable monuments of the greatness of their conceptions ? The bridge at Gard, three leagues from Nimes, is one of them. It serves at once as a bridge and an aqueduct. It goes across the river Gar- don, and joins together the two mountains, between which it Is inclosed. It comprehends three stories ; the third is the aqueduct, which conveys the waters of the Eure into a great reservoir, which * Plin. book 34, chap. 7, and Diodorus Siculus, book 2, relate that Seraira- mis made the mountain Bagistan, between Babylon and Media, be cut out into a statue of herself, which was seventeen stadcs high; that is, above half a French league ; and around it were an hundred other statues, of proportion- able size, though less large. And Plutarch, vol. 2, p. SS5, speaks of a very great undertaking which one Stesicrates proposed to Alexander; viz. to make a statue of him out of Mount Athos, which would have been an hundred and fifty miles in circumference, and about ten in height. His design was to make him bold in his left hand a city, large enough to contain ten thousand inhabit- ants ; and in the other an urn, out of which should flow a river, poured by him into the sea. See also the same, Plutarch, vol. 1, p. 705, in the Life of Alex- ander. Vitruvius, in the preface to bis L2d Book, gives to this statuary the name of Dinocrates. Strabo, lib. 14, p. 641, calls him Chiromocrates. Tzetzes, Chiliad. 8, 199. 2u3 470 ARCHITECTURE AND MECHANICAL SCIENCES. supplies the amphitheatre and city of Nimens. The bridge of Alcantara, upon the Taj^us, is still a work fit to raise in us a great idea of the Roman magnificence : it is six hundred and seventy feet long, and contains six arches, each of which measure above a hundred fe«-t from one pier to the other; and its height from the surface of the water is two hundred fret. The broken remains of Trajan's bridge over the Danube, are still to be seen ; which had twenty piers of free stone, some of which are still standing, a hun- dred and fifty feet high, sixty in circumference, and distant one from another an hundred and seventy. I should never end, were I to enumerate all the admirable monuments left us by the anci- ents ; the slight sketch here given of them, will more than suffice to answer my purpose. As to the ornaments and convrniencies of their buildings, among many I shall mention but one, that of their usins glass in their windows, and in the inside of their aparlments, just in the same manner as we do. Seneca and Pliny inform us, that they decorated their rooms with glasses ; and do not we the same in the use of mirrors and pier glasses ? But what will more shock the general prejudices is, that they should know how to glaze their windows, so as to enjoy the benefit of lij>ht, without being injured by the air ; yet this they did very early. Before they discovered this manner of applying glass, which is so delight- ful and so commodious, the rich made use of transparent stones in their windows such as the agat, the alabaster, the phengites, the talcum, Sec. whilst the poor were under a necessity of being ex- posed to all the severities of wind and weather. If we admire the ancients in those monuments which remain to us of the greatness of their undertakings, we shall have no less reason for wonder in contemplating the dexterity and skill of their artists, in works of a quite different kind. Their works in minia. ture are well deserving of notice. Archytas, who was contempo. rary with Plato, is famous in antiquity, for the artful structure of his wooden pidgeon, which imitated the Qight and motions of a living one. Cicero, according to Pliny's report, saw the whole Iliad of Homer, written in so fine a character that it could be con- tained in a nut-shell : and ./Elian speaks of one'Myrmecides a Mile, tian, and of Callicrales a Lacedemonian, the first of whom made an ivory chariot, so small and so delicately framed, that a fly with its wiing could at the same time cover it, and a little ivory ship of the same dimensions; the second formed ants aud other little ani- ARCHITECTURE AND MECHANICAL SCIENCES. 4? 1 mals out of ivory, which were so extremely small, that their com. ponent parts were scarcely to be distinguished. He says also in the same place, that one of those artists wrote a distitch in golden letters, which he enclosed in the rind of a grain of corn. It is natural here to enquire, whether in such undertakings as our best artists cannot accomplish without the assistance of microscopes, the ancients had no such aid ; and the result of this research will be (hat they had several ways of helping the sight, of strengthening it, and of magnifying small objects. Jamblichus says of Pythagoras, that he applied himself to find out instruments as efficacious to aid the hearing, as a ruler, or a square, or even optic glasses, $iOTrrpz9 were to the sight. Plutarch speaks of mathematical instruments which Archimedes made use of, to manifest to the eye the large, ness of the sun j which may be meant of Telescopes. Aulus Gel. lius having spoken of mirrors that multiplied objects, makes men. tion of those which inverted them ; and these of course, must be concave or convex glasses. Pliny says, that in his time, artificers* made use of emeralds to assist their sight, in works that require a nice eye ; and to prevent us from thinking that it was on account of its green colour only that he had recourse to it, he adds, that they were made concave, the better to collect the visual rays ; and that Nero made use of them in viewing the combats of the Gladia- tors. In short, Seneca is very full and clear upuii this head, when he says, that the smallest characters in writing, even such as almost intir?ly escape the naked eye, may easily be brought to view by means of a little glass ball, filled with water, which had all the effect of a microscope, in rendering them large and clear ; and indeed this was the very sort of microscope that Mr. Gray made use of in his observations. To all this add the burning glasses made mention of before, which were in reality magnifying glasses; nor could this property of them remain unobserved. [Dtttent. SECTION n. Comparative View of the Architecture of different Ages. THAT architecture is of great antiquity is undeniable. But the primitive buildings were very different from the specimens of architecture we now meet with in civilized countries. Jn those mild climates which seem to have been the first inhabited parts of 2 H 4 47'- ARCHITECTURE OF DIFFERENT AGES. this globe, mankind stood more in need of shade from the sun than of shelter from the inclemency of the weather. A very small addi- tion to the sh.i'le of the woods, served them for a dwelling. Sticks laid across from tree to tree, and covered with brushwood and leaves formed th" first houses in those delightful regions. As po- pulation and the arts improved, these huts wcr< gradually refined into commodious dwellings. The mattrials were the same, but more artfully put together. At last agriculture led the inhabitants out of the woods into the open country. The connection between the inhabitant and the soil became more constant and mon iut< resting. The wish to preserve this connection was natural, and fixed estab- lishments followed of course. Durable buildings were more desir. able than those temporary and perishable cottages, stone was sub- stituted for timber. But as these improved habitations were gra. dual refinements on the primitive hut, traces of its construction re- mained, even when the choice of more durable materials made it in some measure inconvenient. Thus it happens that the trunks of trees, upright, represent columns ; the girts 6r bands, which serve to keep the trunks from bursting, express bases and capi- tals ; and the summers, laid across, gave a hint of entablatures ,; as the coverings, ending in points, did of pediments. We shall not enter minutely into a history of the progress of ar- chitecture ; hut :,lmll shew that the above view of ornamental archi. lecture will go far in accounting for some of the more general dif- ferences of national style which may be observed in different parts of the world. The Greeks borrowed many of their arts from their Asiatic neighbours, who had cultivated them long before. It is highly probable that architecture travelled from Persia into Greece. In the ruins of Shushan, Persepolis, or Tehiminar, are to be seen the first models of every thing that distinguishes the Grecian archi- tecture. There is no doubt, we suppose, among the learned, as to the great priority of these great monuments to any thing that .remains in Greece ; especially if we take into account the tombs of the mountains, which have every appearance of greater antiquity than the remains of Persepolis. In those tombs we see the whole ordonnance of column and entablature, just as they began to de. viate from their first and necessary forms in the wooden buildings. We have the architrave, frize, and corniche ; the far-projecting mutulf-s of the Tuscan and Doric orders ; the modillions no less diiiiuct ; the rudiments of the Ionic capital ; the Corinthian capi- ARCHITECTURE OF DIFFERENT AGES. 473 tal iu perfection, pointing out the very origin of this ornament, viz. a number of long graceful leaves tied lound the head of the column with a fillet ; a custom which we know was common in their temples and banqueting rooms. Where the distance between the columns is great, so that each had to support a weight too great for one tr^e, we see the columns clustered or fluted, &c. In short, we see every thins of the Grecian architecture, but the sloped roof or pediment ; a thing not wanted in a country where it hardly ever rains. In the stone-buildings of the Greeks, xthe roofs were imitations of the wooden ones ; hence the lintels, flying corniches, ceilings in compartments, &c. The ancient Egyptian architecture seems to be a refinement on the hut built of clay, or unburnt bricks mixed with straw : every thing is massive, clumsy, and timid; small intercolumniations, and hardly any projections. The Arabian architecture seem a refinement on the tent. A mosque is like a little camp, consisting of a number of little bell tents, stuck close together round a great one. A caravansary is a court surrounded by a row of such tents, each having its own dome. The Greek church of St. Sophia at Constantinople has imitated this in some degree; and the copies from it, which have been multiplied in Russia as the sacred form of a Christian church, have adhered to the original model of clustered tents in the strict* est manner. We are sometimes disposed to think that the painted glass (a fashion brought from the east) was an imitation of the painted hangings of the Arabs. The Chinese architecture is an evident imitation of a wooden building. Sir George Staunton says, that the singular form of their roofs is a professed imitation of the cover of a square tent. The great incorporation of architects who built most of the ca. thedrals of Europe departed entirely from the styles of ancient Greece and Home, and introduced another in which arcades made the principal part. Not finding in every place quarries from which blocks could be raised, in abundance, of sufficient size for forming the far-projecting coruiches of the Greek orders, they relinquished those proportions, and adopted a style of ornament which required no such projections : and having substituted arches for the hori- zontal architrave or lintel, they were able to erect buildings, of vast extent with spacious openings, and all this with very small pieces 474 ARCHITECTURE OF DIFFERENT AGES. of stone. The form which had been adopted for a Christian torn, pie occasioned many intersections of vaultings, and multiped the arches exceedingly. Constant practice afforded opportunities of giving all possible varieties of those intersections, and taught the art of balancing arch against arch In every variety of situation. In a little time arches became their principal ornament, and a wall or ceiling was not thought properly decorated till it was filled full of mock arches, crossing and butting on each other in every direc- tion. In this process in their ceilings these architects found that the projecting mouldings, which we now call the Gothic trac*ry, formed the chief support of the roofs. The plane surfaces included between those ribs were commonly vaulted with very small stones, seldom exceeding six or tight inches in thickness. This tracery, therefore, was not a random ornament. Every rib had a position end direction that was not only proper, but even necessary. Ha- bituated to this scientific arrangement of the mouldings, they did not deviate from it when they ornamented a smooth surface with mock arches ; and in none of the highly ornamented ancient build- ings shall we find any false positions. This is far from being the case in most of the modern imitations of this ipecies of architecture. We call the middle ages rude and barbarous, and give to their architecture the appellation Gothic; but there was surely much knowledge in those who could execute such magnificent and difficult works. The more appropriate terms, w« conceive, would be those of Saxon and Norman architecture, at least, so far as relates to such works in Britain ; giving the first term to that kind distin. guished by the circular arch, and the latter to that distinguished by the pointed arch : for under the guidance of these respective nations did each kind principally display its grandeur and pecu. liarities. The architects of whom we now speak do not appear to have studied the theory of equlibrated arches : but, for a long period, they adopted an arch which was very strong, and permitted con- tiderable irregularities of pressure ; we mean, the pointed arch. The very deep mouldings with which it was ornamented, made tlit arch. stones very long in proportion to the span of the arch. They had, however, with great care,- studied the mutual dependence of arches on each other ; and they contrived to make every invention for this purpose become an ornament, so that the eye required it as a ARCHITECTURE OP DIFFERENT AGES. 475 hecessary part of the building. Thus we frequently see small build- ings haying buttresses on the sides. These are necessary in a large vaulted building, for withstanding theoutward thrust of the vaulting ; but they are useless when there is a flat ceiling within. Pinnacles on the heads of buttresses are now considered as ornaments ; but originally they were put there to increase the weight of the buttress: even the great tower in the centre of a cathedral, which now continues its chief ornament, is a load almost indispensably ne- cessary, for enabling the four principal columns to withstand thecombined dependences of the aisles, of the naves, and transepts. In short, the more closely we examine the ornaments of this archi- tecture, the more shall we perceive that they are essential parts, or derived from them by imitation : and the more we consider the whole style of it, the more clearly do we see that it is all de. duced from the relish for arcades, indulged in the extremes, and pushed to the limit of possibility of execution. From the end of the 15th century, this architecture began to decline ; and was soon after supplanted by a mixed style, if we may venture to call it so ; wherein the Grecian and Gothic, how. ever discordant and irreconcilable, are jumbled together. Con. cerning this mode of building, Mr. VVarton, in his observations on Spencer's Fairy Queen, has the following anecdotes and remarks: " Although the Roman or Grecian architecture did not begin to prevail in England till the time of Inigo Jones, yet our communi- cation with the Italians, and our imitation of their manners, pro. duced some specimens of that style much earlier. Perhaps the earliest was Somerset. house in the Strand, built about the year 1549, by the duke of Somerset, uncle to Edward VI. In the year 1613, the magnificent portico of the schools at Ox. ford was erected, in which, along with the old Gothic style, the architect has affectedly displayed his extraordinary skill in the Grecian and Roman architecture, and has introduced all the fire orders together. " In the 15th and l6th centuries, when learning of all kinds bpgan to revive, the chaste architecture of the Greeks and Romans seemed, as it were, to be recalled into life. The first improve, ments of it began in Italy, and even owed their existence to the many ruins of the ancient Roman structures that were to be found in that country, from whence an improved method of building was gradually brought into the other countries of Europe : and though 476 ARCHITECTURE OF DIFFERENT AGES. the Italians for a lon^ time retained the superiority as architects, over the other European nations, yet as men of genius from all quarters constantly visited Italy for the purpose of improvement in architecture, as well as the other arts, since that period they have been equalled, if not surpassed, by architects of other nati. ons, and even of our own country." The orders, as now executed by architects, are five, viz. the Tuscan, the Doric, the Ionic, the Corinthian, and the Composite ; which are distinguished from each other by the column with its base and capital, and by the entablature. The Tuscan order is characterised by its plain and robust appearance, and is therefore used only in works where strength and plainness are wanted; it has been used with great effect and elegance in that durable monu- ment of ancient grandeur, the Trajan column at Home; indeed general consent has established its proportions for such purposes beyond all others. The Doric possesses nearly the same character for strength as the Tuscan, but is enlivened by its peculiar orna- ments ; the triglyph, mutule, and guttae or drops under the trig, lyph ; these decorations characterise the Doric order, and in part are inseparable from it. Its proportions recommended it where united strength and grandeur are wanted. The Ionic partakes of more delicacy than either of the former, and therefore as well as on account of its origin, is called Feminine, and not improperly supposed to have a matronic appearance. It is a medium between the masculine Tuscan and Doric, and the virginal sleoderness of the Corinthian : the boldness of the capital, with the beauty of the shaft, makes it eligible for porticoes, frontispieces, entrances to houses, &c. Denteles were first added to the cornice of this order. The Corinthian possesses more delicacy and ornament than any other order ; the beauty and richness of the capital, and the delicacy of the pillar, render it the most suitable in those edifices where magnificence and elegance are required. On this account it is frequently used for the internal decoration of large state rooms ; in which it has a chaste appearance, though at the same time su. perb. The Composite order is the same as the Corinthian in its proportions, and nearly alike in ornamental properties. The ad. dition of the modern Ionic volute to the capital, gives a bolder projection. It is aplicable in the same manner and in the same cases as the Corinthian. The first complete system of architecture we meet with is that LABYRINTHS. 477 of Vitruvius, who lived in the reign of Julius Caesar and Augustus. Since Vitruvius, the principal authors are Alberti, Baldus, Barba. rus, Blondel, Catanei, Demoniosius, Freard, Goldman, Gulicl. mus, Langley, Mayer, Nicholson, Pain, Palladio, Perrault, Ri. vius, Serlio, Scamozzi, Vignoli, and Ware. On the subject of Gothic architecture, we refer to Essays on Gothic Architecture, published by Taylor, and to a paper in vol. iv. Trans. Royal So. ciely Edin. by sir James Hall. \_Pantologia. SECTION III. Labyrinths. AMONG the architectural curiosities of antiquity, there are few entitled to more attention than the complicated and extraordinary edifices known by the name of labyrinths. The most celebrated were those of Crete, Lemnos, and Egypt. The first stood near mount Ida, and was the production of the celebrated Daedalus. All we know of it, however, is from loose rumour, or casual refer, ence. Even in Pliny's time not a vestige of it was to be traced ; and Bcllonius has been so much of an infidel as to conjecture that it was nothing but an ancient quarry excavated by digging the stones that served to build the neighbouring towns of Gortynas and Grossas. The labyrinth of Lemnos is aupposed by Pliny to have been more magnificent than that of Crete, when both were in their full per. fection. It was a vast and splendid pile supported by forty columns of extraordinary height and circumference. The architects em- ployed in raising it were, Zinilus, Rhodus and Theodora «, the last a native of the island. In Pliny's time its vestiges wore still o be traced ; but Bt llonius could not discover a relic of it during his visit to Lemnos. Of all the labyrinths, however, of antiquity, that of Egypt was the largest and most costly : and it is said to have furnished to Daedalus the model of that of Crete, though he imitated not more than the hundredth part of it. It was so extraordinary, that He. Todotus who saw it says, that jt far surpassed the report of fame, being, in his judgment, even more admirable than the pyramids. As there were at least three bnildings of this kind, ancient writers, 473 LABYRINTHS. not distinguishing them, generally speak but of one, and conse- quently with great confusion and disagreement. They tell us the la!>yrinth of Egypt stood in the Heracleotic nome, near the city of Crocodiles, or Arsinoe, a little above the lake Mccris. Pliny places it in the lake, and says, it was built by Petesuccus, or Tithoes, one of the demi-gods, four thousand six hun. dred years before his time ; but that Demoteles would have it to be the palace of Motherudes ; Lyceas, the sepulchre of Moeris ; and others the temple of the Sun. It is recorded by Manetho, that Lacha. res or Labares the successor of Sesostris, built a labyrinth for hia monument. An.l Diodorus writes, that Mende.0, or Marus made another for the samepurpose, which was not so considerable on account of its magnitude, as for the artificial contrivance of it ; but this seems to be adifferent building from that described by him a little after ; which is, 'in all probability, the same with the labyrinth of Herodotus ; for they both agree in the situation. They say it was the work of twelve kings, among whom Egypt was at one time divided ; and that they built it at their common charge. This structure seems to have been designed as a pantheon, or universal temple of all the Egyptian deities, which were separately worshipped in the provinces. It was also the place of the general assembly of the magistracy of the whole nation, for those of all the provinces or nomes met here to feast and sacrifice, and to judge causes of great consequence. For this reason, every nome had a hall or palace appropriated to it ; the whole edifice containing, ac- cording to Herodotus, twelve ; Egypt bting then divided into so many kingdoms. But Pliny makes the number of these palaces sixteen, and Strabo, as it seems, twenty-seven. Herodotus tells us, that the halls were vaulted, and had an equal number or doors opposite to one another, six opening to the north, and six to the south, all encompassed with the same wall ; that there were three thousand chambers in this edifice, fifteen hundred in the upper part, and as many underground ; and that he viewed every room in the upper part, but was not permitted, by those who kept the palace, to go into the subterraneous part, because the .sepulchres of the holy crocodiles, and of the kings who built the labyrinth were there. He reports, that what he saw seemed to surpass the art of man; so many exits by various passages, and infinite returns, afforded a thousand occasions of wonder. He passed from a spacious hall to a chamber) from thence to a private cabinet ; then again into other LABYRINTHS. 479 passages out of the cabinet*, and out of the chamber into the more spacious rooms. All the roofs and walls within were incrusted with marble, and adorned with figures in sculpture. The halls were surrounded with pillars of white stone finely polished ; and at the angle, where the labyrinth ended, stood the pyramid formerly mentioned, which Strabo asserts to be the sepulchre of the prince who built the labyrinth. To this description of Herodotus, others add, that it stood in the midst of an immense square, surrounded with buildings at a great distance ; that the porch was of Parian marble, and all the other pillars of marble of Syene 5 that within were the temples of their several deities, and galleries, to which was an ascent of ninety steps, adorned with many columns of porphyry, images of their gods, and statues of their kings, of a colossal size ; that the whole edifice con. sisted of stone, the floors being laid with vast flags, and the roof appearing like a canopy of stone ; that the passages met, and crossed each other with such intricacy, that it was impossible for a stranger to find his way, either in or out, without a guide; and that several of the apartments were so contrived, that on opening of the doors, there was heard within a terrible noise of thunder. We shall subjoin part of the description given by Diodorus of a fabric, which though he does not call it a labyrinth, but a sepulchre, yet appears to be the same we are now speaking of. He says it was of a square form, each side a furlong in length, built of most beautiful stone, the sculpture and other ornaments of which posterity could not exceed : that on passing the outward inclosure, a building presented itself to view, surrounded by an arcade, every skle con. sisting of four 'hundred pillars; and that it contained the ensigns or memorials of the country of each king ; and was, in all respects, a work so sumptuous, and of such vast dimensions, that if the twelve princes who began it, had not been dethroned before it was finished, the magnificence of it could never have been surpassed* Whence it seems, that Psammetichus, one of the twelve, who, ex. pelling his associates, made himself master of all Egypt, finished the design, but not with a grandeur answerable to the itsi >f the struc. tare ; though Mela attributes the glory of the wlioV to that king. The solidity of this wonderful building was sud-, that it with' stood, for many ages, not only the rage of time, but that of the in. habitants of lleracleopolis, who, worshipping the ichneumon, tht 480 GREAT WALT. OF CHINA. mortal enemy of the crocodile, which w~- the peculiar deity of Ar. sinoe, bore an irreconcileablf hatred ID the labyrinth, which s» - also for a sepulchre to the sacred crocodiles, and therefore they strove to demolish it. Pliny says, it was remaining in his d and that about five hundred years before Alexander, Circummon eunuch to king Nectabis, was reported to have bestow -mall reparations on it, supporting the building with beams of acacia, or the Egyptian, thorn, boiled in oil, while the arche-j of square stone were erecting. » [dncicnt Univ. Hist. SECTION IV. Great Wall of China. THE chief remain of ancient art in China is that stupendous wall, extending across the northern boundary *. This work, which is de- servedly esteemed among the grandest labours of art, is conducted over the summits of high mountains, some of which rise to the height of 5225 feet, across the deepest vales, over wide rivers by means of arches ; and in many parts is doubled or trebled to com. mand important passes': at the distance of almost every hundred yards is a tower or massy bastion. The extent is computed at 1500 miles; but in some parts of smaller danger it is not equally strong or complete, and towards the N.W. only a rampart of earth. For the precise height and dimensions of this amazing forti- fication the reader is referred to Sir George Staunton already quoted, whence it appears that near Koopekoo the wall is twenty-five feet in height, and at the top about fifteen feet thick : some of the towers, which are square, are forty. eight feet high, and about forty feet wide. The stone employed in the foundations, angles, &c. is a strong grey granite ; but the greatest part consists of bluish bricks, and the mortar is remarkably pure and white. Sir George Staunton considers the era of this great barrier as absolutely ascertained, and he asserts that it has existed for two thousand years. In this asseveration he seems to have followed Du llaldc, who informs us that " this prodigious work was con. stincted two hundred and fifteen years before the birth of Christ, by the orders of the first emperor of the family of Tsin, to protect * SirG. SUuiniun'k tmbassy, vol. ii, 360. 8vo. « TEMPLE OF EL KPHANI A. 481 three large provinces from the irruptions of the Tartars*." But in the History of China, contained in his first volume, he ascribes this erection to the second emperor of the dynasty of Tsin, namely Chi Hoang Ti j and the date immediately preceding the narrative of this construction is the year 137 before the birth of Christ t. Hence suspicions may well arise, not only concerning the epoch of this work, but even with regard to the purity and precision of the Chi- nese annals in general. Mr. Bell, who resided for some time in China, and whose travels are deservedly esteemed for the accuracy of their intelligence, assures us £, that this wall was built about six hundred years ago (that is about the year 1160), by one of the em- perors, to prevent the frequent incursions of the Monguls, whose numerous cavalry used to ravage the provinces, and escape before an army could be assembled to oppose them. Renaudot observes that no oriental geographer, above three hundred years in anti- quity, mentions this wall § : and it is surprising that it should have escaped Marco Polo ; who, supposing that he had entered China by a different rout, can hardly be conceived, during his long resi- dence in the north of China, and in the country of .the Monguls, to have remained ignorant of so stupendous a work H. Amidst these difficulties, perhaps it may be conjectured that similar modes of de- fence had been adopted in different ages; and that the ancient rude barrier having fallen into decay, was replaced, perhaps after the in. vasion of Zingis, by the present erection, which even from the state of its preservation can scarcely aspire to much antiquity. [Du Halde. S taunt on. Pinkertqn. SECTION V, Temple of Elephanta. WE got into our boat at Ma za gong a little before sunrise, and had the pleasure of marking the gradual increase of day as it broke over the Mahratta mountains. First the woody tops of Caranja and Elephanta became illuminated, then Bombay, with its forts and villages stretching along the north of the bay, while the bases of the rocky islands to the south, slowly became distinguishable from the reflecting waves. After an hour's row, during which we * Tome ii.. p. 51. t Tome i.S40- | Travels, ii. 112. 8vo. S Ut supra, 137. y Some, however, deny that be entered Cbina. TOL. YI. 2 I TEMPLE OF ELEPHANTA. Butcher's Island, called by the natives Deva Devi, or holy island, \\e an'ufd at Klephanta, a mountain Me with a double top wooded to the summit: Opposite to the landinir-p'nc" is the co- lossal stone elephant, from which the Portuguese n:im<-d the place. It is now cracked and mutilated, as tradition says, by the Portu- guese. It must have been carved out of tin- rock on whii-h it stands, for it appears too large to have been carried to its pi situation. After passing a village which, as well as whole inland, the natives call Gharipoori, we ascended the hill through romantic passes, sometimes overshadowed with wood, sometimes walled by rocks, till we arrived at the cave. We came upon it unexpectedly, and I confess that I never felt su»h a sensation of astonishment as when the cavern opened upon me. At first it appeared all dark- ness, while on the hill above, below, and around, shrubs and flowers of the most brilliant hues were waving in the full sunshine. As I entered, my sight- became gradually more distinct, and I was able to consider the wonderful chamber in which I stood. The entrance is fifty-five feet wide, its height is eighteen, and its length about equal to its width. It is supported by massy pillars, carved in the solid rock; the capital of these resembles a compressed cushion bound with a fillet ; the abacus is like a bunch ot i supporting a beam, six of which run across the whole cave; below the capital the column may be compared to a fluted I ell ri^lm, on a plain octagonal member placed on a die, on each corner of which sits Hanuman, CJanesa, or some of the other inferior gods. sides of the. cavern arc sculptured in compartments, representing persons of the mythology ; but the end of the cavern opposite