Napkin rings, 430, 476 Natal, passage to, 287, 427 Natural forces, 623; selection, 311, 499 Nature, sketching from, 166, 404, 427 Naval architecture, 191, 259, 285, 382 Needle magnetic, 263, 286, 310, 417; Nets, 405; nets, fishermen's, 358, 380 New comet, 358; dye-wood, 502; veloce Nitrate of silver, 550, 573, 574, 597, 598, 620; nitrate of silver stains, 215, 260 Nitric acid, 45; nitrous acid, 598 Oliver Cromwell shilling, 358, 381 Ores: auriferous, 45; iron, 46: lead, 430 Organ, the, 22, 69, 167, 215, 263, 287, 310, 384, 428, 550, 573, 596; organ: accordion stand, 262, 452, 546; barrels, 287, 428, 475, 523; movement to harmonium, 287: pipes. 311, 334, 622; stops, 257; PADDLE steamer, model, 599; pad- Paint 95; paint: for aquarium, 383, 594; for boats, 262; on bicycles, 21, 66; granitic, 26, 66; hard white, 452; remelt- Painting: ancient, 455; bath, 623; boiler, 262: bronzing and painting iron, 550; carriages, 22; cistern, 527, 572; coaches, 550, 619; decorative, 191, 237; glass, 167, 335, 380; landscape, 166; stones in jewellery, 215, 427; tarred wood, 166, 189, 286; theatrical scenes, 45, 68, 92; windows, 262, 286 Palisading, iron, 166, 189, 236 Pancreatic emulsion, 574; pancreatine, Pans: harmonium, 213, 527; loam, 262, Paper: collars and cuffs, 190, 237; mourn- ing, 502; negatives, 23; oiled, 190, 237; staining, 95; stencilling, 117, 187; trac- ing, 285, 502, 525, 547; waterproofing, Paper-hangings, 142, 143, 189, 236, 335, 380 Paraffin: oil, 549; scale, 262, 286; trans- parent, 190; paraffin lamp, cement for, Parasites on canaries, 286, 333 Paris, 382; Paris, plaster of, 599, 621 Part of sphere, contents of, 118 for clothing iron rollers, 21; razor, 19; for stropping tools, 95 Pattern varnish, 18, 66, 91; patterns: cylinder, 215, 260; girder, 166, 213, 259; making. 118; measuring, 43 Paving, asphalte, 479, 501, 525 Pen, drawing, 382, 428; pens, 502 Pencil for lathe, 94; pencils, lead, 45, 92 Pendulum, 43, 45, 527, 549, 550, 572, 623; pendulum springs for watch, 597, 619, Perforating for embroidery, 46, 116 Photographic, 20, 23, 46, 92, 95, 187, 214, 215, 311, 333, 359, 381, 382, 427, 428, 452, 478, 479, 524, 525, 526, 527, 547, 519, 571, 578, 575, 595, 598, 618, 619, 620; photo- graphic: camera, 191, 259, 309; views, 358; photographs of Australian scenery, Pianoforte, 166; pianofortes: defective, 19; felt, for, 238; keys and teeth of, 66; Pickles, 262 Picric acid, 550, 573, 596 Picture mount, 238 Piece, brake, 574, 620 Pig iron, 70, 139 Pike fishing, 382, 406 Pills, 20, 66 Pine wood, 21 Pinions of watches, 478 Pins: brooch, 94, 117, 140; piano, 382, 476, Pipes: flexible, 287, 427; organ, 311, 334, 622; pedal, 69; steam, 43, 66, 190, 259; sweating water, 20; syphon, 190, 259 Pitch, 20; pitch pine wood, 21: pitch of propeller, 215, 200; pitching cogwheels, Pivots: turning, 238, 261; watch, 166, 259 Plane mirror, mounting, 527, 547; planes, Planet Neptune, 94, 117; planets, situa- Plants: starch, 215; zinc, 20, 66 Plaster: court, 454, 500, 523; felt and amadou, 21 from glass, removing, 526; hardening, 190, of Paris, 599, 621 Plate-glass, gilding, 166, 213; plates: ba- lance, metal, 502; battery, 20; boiler; 359; brass, 94, 527, 596; burnishing, 215, 427; copper, 167, 236; dividing. 21, 44, 238, 261; division, 527, 549, 572, 618; screw, 455, 478; steel, 358, 381, 527; Platt and Mather's piston, 478, 525 Points: of drills, 623; legal, 527, 549; Poisoning: cantharides, 191, 214, 237, 259 Polarised light, 311, 357, 380, 428 chains, 215; fretwork, 46; granite, 45, 164; horn and shells, 46; plaster of Paris, 599, 621; Scotch pebbles, 46, 68; speculum, 430: steel, 214, 237, 260 stones, 69: vulcanised india-rubber, 550; vulcanite, 573, 596; walking sticks, Pond for gold fish, 574, 620 335 Portable: carpenters' bench, 45; engine, Position of magnetic pole, 262 Pottery: bricks and, 287, 358, 453; glaze Powder: bleaching, 238, 427, 452; blue, 44; soap. 430; teeth, 119, 141, 164 Power, boiler, 214; double motive, 238, 310; engine, 574, 598; horse, 310, 334, 356, 502, 526, 527, 547, 548, 550, 595, 596; lifting, 21, 44; of metal, twisting, 189, 259, 285; motive, 623; numbers. 262, 286; of spiral springs, 22; steam, 45, 92; of telescopes, 189; for velocipede, 479; water. 43, 46, 66, 68, 92, 139, 574, Preserving: eggs, 189; flowers, 311, 335, Presses: binders' cutting, 21, 44; steam Pressing ladles into shape, 215 Prices: boat, 93; carpenters' work, 18; Printing, 454; printing: anastatic, 335; books on, 358, 381; copper-plate, 94; in gold or bronze, 550, 572; names on Prints: on cardboard, 599; cleaning, 502, wrinkles in, 599 Prisms: bisulphide of carbon, 262, 475; Problems: 19, 21, 22, 44, 45, 67, 69, 91, 92. 115, 118, 141, 142, 165, 215, 238, 286, 335, 357, 404, 431, 454, 475, 477, 478, 500, 501, 524, 550, 574, 595, 597, 598, 619, Proctor's telescope stand, 598 Projection: 70, 93, 140, 142, 188; projec- Propellers, screw, 215, 260, 575 Pulleys: loose, 214, 259; Mendoza, 215; Pumps, 44, 66, 117, 141; pumps: air- strung, 335, 380; Appold's, 24, 140: force, 15, 287, 406, 594; model engine, 143; Rel: bronzing, 454, 477; coral, 478; face, Reed: organs, 358; organ pipes, 622; Re-enamelling zinc clock dial, 454, 618 Reflecting telescope, 527, 549 Relacquering brass-work, 190, 427, 454 Remanufacturing india-rubber, 262 Removing: fly-spots, 22: oil paint from silk, 45, 92; paint, 262, 286; plaster from glass, 526; rust, 66; wrinkles Rendering: calico air-tight, 623; bone Repairing india-rubber combs, 239 Repolishing watchguards, 21, 66 Republic of Guaiana, 262, 475, 546, 547, Resin beeswax and, 574; dissolving, Rest, slide. 310, 334, 356, 380 Restoring freshness to water. 479, 501, 525 Re-tinning cast-iron, 238, 382, 404, 427 Reversing: eccentric, 17: engines, 478 Revolutions of blast fan, 502, 548 Re-working vulcanised india-rubber, 406 Rhumkorff's coil, 45, 68, 69, 142 Road-measuring, 431, 477; road-steamers, 118 Rods: fishing, 166, 382, 406, 427; fly, 267, Rolled brass, fret-cutting, 94, 117 Rope-bands, 118; ropes, 287, 334 Rotation of the earth, 190, 599, 621 Round zinc wire, 287 Routes: overland, 22, 91; sea, 383 Rubbing down silvered circles, 45, 68; rubbings; coins, 527; inscriptions, 94 Rules: croquet, 167, 404; finding sizes of Rust: removing, 66, in water, 113 Saddle-spring for veloce, 383, 429; saddles, Safety-valves, 214, 259, 260, 285, 287, 309, Saw: frame, vertical, 21, 115: teeth, 46. 139; saws, brazing, 358, 381; sawing Scene-painting, 45, 68, 92; scenery, Aus- Schools, continental, 406, 430 Science and art examinations, 575, 622; science questions, 143, 188, 622 Screw: cutting, 45, 262, 335, 479, 525, 547, 599, 622; engine for canoe, 287, 427; plates, 455, 478: propellers, 215, 260, 575; steamer, 118, 141; taps and dies, Securing iron cramps to stone, 455, 501 Seeds: China grass, 139; grinding, 237, 452; stock, 382, 453, 499, 547 Selection, natural, 311, 499 Sensitive flames, 359, 382, 405 Separating: bees'-wax from resin, 574; Setting: eccentrics, 311; jewelled holes, Sewage, 238, 404 Sewing-machines, 238, 287, 382, 429, 430, Shafting, lining-out, 454, 547; shafts Sheathing iron ships, 94, 140, 359 Shells: gold, 455, 595; oyster, 599; polish- Sheep's: horns, dissolving, 262; skins, Sheet: brass, stamping, 22; iron rudder, Shilling, Oliver Cromwell, 358, 381 Ships: displacement of, 263, 334, 404, 599; construction of, 575; iron, 622; sheath- Shop frame, revolving, 262, 475 Sight, short, 22, 44, 598, 621 Signal, time, 238, 261 Silica, 382, 453 Silk-dressing machine, 575; silk plush, Silver: balls, 166, 541; chloride of, 407, 454; coins, 190, 213, 214, 236, 237, 259, 335, 957, 859, 350, 351, 450, 476 478, 624, 527, 547, 572; German, 237, 269; lead, silver from, 69; leaf, tarnished, 94, 117; nitrate of, 550, 573, 574, 597, 598, 620; Silvered circles, rubbing down 4, 68 Silvering: diagonal planes, 191; clock- dials, 68, 116, 235, 407, 527, 618 Situation of planets, 190 Size, colouring, 599, 618; sizes of: boat, Sketching from nature, 166, 404, 427 Skins: dressing. 599; softening, 454, 499 Slate: cistern, 258, 404; engraving on, 22; 44. 115; slates, enamelling, 622 Slot-cutting, 93, 117, 215, 237 Small: copper coin, 119, 141; furnace, 164: planing machine, 382, 622; wheels, Smoke: burning, 358, 457; on walls, 118, Soda crystals, 118, 190, 451, 526, 571; soda- water, 287, 310, 404, 475, 499; soda-water Soft: metal, soldering, 311, 380; soap, 68; Softening: ash timber, 359, 381; cast iron, Soldering 22, 67, 215, 260, 311, 358, 380 455, 500, 547, 599; soldering: brass, 335, 380; tin, 23; soft metal, 311, 380 Solid contents of cylindrical figure, 43; Solutions: chemical, 166, 404, 431, 477; Spirit level, 453; spirit, methylated, 454, 477, 499, 523, 549, 571, 572, 594, 596, 618; Splitting: quills, 21; whalebone, 406, 499 Sportsman's velocipede, 335, 357 Spring bow, 69, 117; spring steel. 46; springs: buffer, 214, 452; pendulum, 550, 597, 619, 622; spiral, 22; veloce Stained glass, 22, 66, 67, 115 Staining: gut fishing lines, 526, 548, 571: paper, 95; wood, 20, 43, 66, 262 Stains: on cloth, 358, 381, 405; iron, 287, 310, 334; nitrate of silver, 215, 260; on steel, 622; in veneer, 358; on wood, 622 Stamping, 94; stamping: in colours, 19; sheet brass, 22; tea trays, 358 Stands: accordion, 262, 452, 546; re- flector, 622; telescope, 215, 260, 575, 598 Starch, 599; starch and cornplant, 215; Steam, 575, 620; steam boilers, 214, 479, 525; carriages, 359, 383, 622; cylinders, friction in 406; engine, 574, 598; engine, model, 21, 143, 166, 213, 236, 454, 477; expansion of, 599; indicator, 46, 92; joints, 526, 549, 571; pipe joints, 190, 259: pipes, disconnecting, 43, 66; power of, 45, 92; punching press, 527; rings of, 17; roarer, 22; speed, 23, 68; versus air. 575; wanted, 46, 92; water and, Steamers: model paddle, 599; road, 118; Steaming: bones, 478; bottles, 358; food for cows, 263, 310; wood, 215, 237 Steel demagnetising, 476; gauges, 359; lead and, 358, 381; mandrels for spin- ning lathes, 526; melting, 46; Mushet's, 287; needle wire, 599; ornaments, 19; polishing, 214, 237, 260; plate, en- graved 358, 381; plates, 527; spring, 46; Stencil colours on paper, 117, 187; stencil Stereotyping, 599, 600 Sticks: emery, 550; walking, 599 Stock seed, 382, 453, 499, 547 Stops: organ, 287; trumpet, 623 Storm glass, Fitzroy's, 335, 857 Stoves air, 94; gas, 69, 93, 359 Strange: mechanical movement, 45: Straw and water-glass houses, 550, 619 Substitute for cod-liver oil, 383, 594 Sulphates of ammonia, 22; sulphate of atropia, 142: sulphate of copper battery, 455, 501; sulphate of lead battery, 22, 67, 115, 142, 188; sulphate of zinc, 166, Summer beverages, 94, 117, 140 Sun dials, 19, 118, 164, 285, 358, 523, 547, 574, 597; sun glass for telescope, 45, 92 Superficies, mensuration of, 502, 526, 548 metal, 502, 547; trays, 358; urn, 46 Teeth: affection of, 118, 141, 164: artifl- cial, 166; of change wheels, 550; of Telegraphs: domestic, 69; writing, 118, Telegraphy, 527, 572, 596, 619 Telescopes: construction of, 46, 335; Gregorian, 311; large, 142; refracting, 22, 23; stands for, 215, 260, 575, 598; Telescopic, 22, 45, 46, 69, 92, 95, 117, 142, 143, 189, 215, 238, 260, 335, 358, 455, 502, 524, 527, 549, 550, 572, 575, 596, 622, 623 Temperament of English concertina, 502 Temperature: beneath trees, 335, 404; Tempering: brace bits, 454, 477, 500; buffer springs, 214, 452; drills, 19, 66, 139, 212, 235; steel needle wire, 599 Tender feet, 550, 572, 596, 619 Testing: boiler, 190, 259, 285; gold, 406, 571; milk, 43; oil, 287, 310, 406, 453; tobacco and nux vomica, 311, 404 Theatrical scene painting, 45, 68, 92 Thermometer, 238, 260, 261, 286 Three-wheeled veloce, 262, 309, 310, 356 Timber: ash, 359, 381; breaking weight of, 69, 93; joints, 599; measuring, 20; Time, 68, 70; time-gun, electric, 526; time, sidereal, 358, 381; time signal, Tobacco: fumes, 117; papers, 93; tobacco and nux vomica, tests, for, 311, 404 Tongue rivets for harmoniums, 69 Toning bath, 573, 574, 597, 620 Tools: binders', 600, 622; screw, 455, 478, 523; strapping, 95: for swaging bolts Town gardening, 550, 572, 596, 619 Tracing cloth and paper, 237, 285, 309, 502, Transferring engravings to wood, 527, 547 Traversing, true heart for, 575 Treatment of chrysalis, 382, 571 Tree-stubber, 550; trees, temperature be- Tricycles, 43, 238, 262, 285, 309 Trigonometrical difficulty, 406, 429 Tropical: climate, 835; fibres, 335, 380, 618 Tubes barometer, 22, 190, 191, 235, 310, 356, 427, 452, 498; brass, 502, 526; elec- trical, 502 level, 453; speaking, 600, Tuning: bellows for harmonium, 287, 499, 550; concertina, 118; by equal tempera- ment, 481, 477; harmonium reeds, 69; Turner's Club, Amateur, 166, 189 Turning, 189, 213, 236; turning: cast-iron, 262, 310; copper, 502, 526; pivots, 238, 261; spheres, 455, 478, 501, 524; wooden- Turning an harmonium into an American Turpentine, adulteration of, 166, 189 Twisting power of metal, 189, 259, 285 University examinations, 239, 261 Unsolved problems, 69, 92 Urns: bronzing copper, 599, 621; tea, 46 VACUUM: in condensing engine, Value of: coin, 287, 475; testril, 358, 381 Valve facings of cylinders, 574, 620; valves, 20, 70, 140; valves: Cornish, 311, 356; rubber, 622; safety, 214, 259, 260, 285, 287, 309, 310, 355, 478, 547; slide, 46, 92, 238, 286, 479; starting, 69, 140; Veloce, three-wheeled, 262, 309, 310, 356 Velocipedes, 67, 95, 140, 262; velocipedes: **Edinburgh," 262; "English," 142, 188, 190: Lamborne's, 430, 547; "Leo's," 166; motive power for, 479; roundabout, 214; saddle spring for, 383, 429: "Shiptonian," 311; sports- men's, 335, 357; Stanway's, 22, 333; water, 287, 334; wheels for, 94, 333 Vencer, stains on, 358; veneers for har- Vertical: engines, 430, 476; saw frames, Vessel propelled by windmill, 550, 573, 596, 619; vessels: galvanised, 358, 381; Vinegar, 358, 381, 382, 405, 428, 429 Violin, 46; violin strings, 527 Voyage, sea, 17 Vulcanised india-rubber, 118, 141, 214, Walking tour, 94; walking-stick air Walls: damp, 380; decoration of, 430; Warming by hot water, 359 Waste, cotton, 19 waste, soft, 94 Water, 45; water: analysis, 238, 2×5, 311, 380; in baths, 118; chalk and, 214, 333; colours, 551; condensing. 454 conveyance of, 559; distilled, 335, 358, 380; filtered, 479, 501, 525; forcing, 262, 452, 475; hard, 119; insects in, 454: meters for, 166, 475; motion of, 18, 45, 92, 116, 139: pipes; sweating. 20; power, 43, 46, 66, 68, 92, 139, 574, 622; pressure. 574, 598, 620; pump, 358, 381; raising, 46, 92, 143, 432; rust in, 118; soda, 287, 810, 404, 475, 499; softening, 599; steam and, 143, 285; supply, 622; velocipede, 287, 334; weight of, 117, 140, 164, 238, Water barometer, 479, 502, 526, 575 Water-glass, 478, 501; water-glass and Waterproof, 430, 376; water-proof glue, 21; waterproofing: calico, 623; cloth, 238, 261, 285; paper, 118, 141, 167 Waxing engraved brass plate, 94 Weights of ball, 502, 526, 548, 551, 595, 597; chemical solutions, 431, 477 frustrum, 142, 165, 188, 213, 235; gas. 286; metals, 551, 619; rails, 527, 596, 619; water, 117, 140, 164, 238, 261, 309, 355; wire, 622; wrought-iron gates, 45 Welding: cast steel, 502, 548, 571; forks, Wenham's parabolical reflector, 623 Whalebone, splitting, 406, 499 Wheel: cutting, 19, 215, 237, 262; gearing 310, 356, 380; making, 142; skates, 22 Wheels: bicycle, 44, 142, 188; change. 454, 500, 550, 572, 575, 620; cog. 94 drying small, 454, 499; emery. 498 fly, 93, 191, 214; sizes of, 310, 334, 356 velocipede, 94, 333; watch, 478; water White brass, Parsons's, 311; coral, clean ing, 166, 335, 380; flint, 382, 453; fur niture cream, 479, 525; metal bearings, 18: metal, hard, 550; paint, 262, 452 Wind: the cast, 23; instruments, 69 Winding drums, conical, 262, 599; silk Window frame, revolving 262, 475 Windmills, 69; windmills: model, 623; for propelling vessels, 550, 578, 596, 619 Winter's electrical machine, 47 Wire binding magnetic, 575; colouring 358, 381; covering, 46, 215; joining 44, 66; needle, tempering, 599; netting machine, 382; steel, 237, 358, 427, 475 With's reflector, 382 Wood engraving, 262, 527; wood and Woods: Bankal, 94, 117; dye, 502 feathers in, 17; foreign, 623; green heart, 550; inlaying fancy, 167: pine 21; rendering incombustible, 166, 189 seasoning, 190; stains in, 622; staining 20, 43, 66, 262; steaming, 215, 237 tarred, 166, 189, 236; Tonga bean, 430, 47 Wool, 21; wool: scribbling, 238; yarn Woollen carpets, 358 Work: carpenters', 18; mill and forge, 16 Worm for vice-box, 46, 92; worm-eater Writing: ink, 478, 501, 502, 524, 526, 548 on glass, 69, 93, 116, 142; signs, 382 618; telegraph, 118, 187; tickets, 23, 52 Yarn, hosiery, 22; yarns, dyeing, 551 Zinc: ashes, 21; clock-dial, 454, 618 plant, 20, 66; plate for battery, 20 THE ENGLISH MECHANIC AND MIRROR OF SCIENCE AND ART. AS MECHANIC AND MIRROR OF SCIENCE appears this week in an enlarged size and an altered form. In putting the advertisement pages outside, we have acted in obedience to a generally expressed wish on the part of our subscribers. No doubt the publication will be subject to some disadvantages from this change, as it will be less exhibited in shop windows, and will therefore be less under the eye of the passing public. On the other hand, our subscribers, as we intimated last week, will derive decided advantages from the alteration, and they may easily make up for any disadvantage we may suffer by introducing the work to an enlarged circle of readers. OURSELVES AND OUR SUBSCRIBERS. ENGLISH MECHANIC is therefore a reflex of the creature asked us, of all things in the world, to promised last week, the ENGLISH intelligence and the generosity of thousands buy a brick, showing us at the same time a of subscribers. Its contributors are numbered small engraving of a brick on a card. We asked not by units, as in most publications, but actually her what she meant, and she said they were by thousands. Each one contributes according to about to build in some part of the north of Engthe wealth of his intelligence, or his desire to im- land a temperance hall, and that it was comAny one who has listened to puted that each brick in the building, and the part it to others. debates in mutual improvement societies, at an labour of putting it there, would cost about a educational or scientific conference, or in Parlia- penny, and she wanted us to assist to build the ment, knows the standard of eloquence varies with hall to the extent of a single brick. Did she the speaker. Some speak well, and to the point, and possess fewer charms, and speak less musically, we should have bought a brick. As it was, others occupy time to very little purpose; say what others have said before them, and in a less effective though pennies were of some importance to us It is then, we bought more than one, and have the way, or say things that are erroneous. pretty much the same in our ENGLISH MECHANIC's satisfaction at this moment of remembering that national improvement society. Some correwe assisted in a very small way in raising a temWe have increased the size of the paper because spondents write about what they thoroughly un- perance hall. So it is with the contributors to we desire to satisfy the largest number of sub-derstand in appropriate language; others are less the ENGLISH MECHANIC. Each one, by replying scribers. Some may say, Why not increase fortunate. They either ask questions which others to a single query asked by a brother reader, conthe number of pages, instead of increasing the have asked before, or go over ground which tributes his brick to the Temple of Knowledge. size of the pages? Our answer is, Because others have trodden with more effect. But increasing the number of pages involves the woe betide them if they make mistak es. necessity of double machine labour, and con- Then a half a dozen are ready with pen and ink, sequently double expense. When we have from not, as they say in the House of Commons, to time to time given a Supplement of Eight catch the Speaker's eye, but to seize the Editor's Pages, it has cost us nearly as much for attention, in order to correct the mistake,and rebuke, machine work—that is, for working off the sheets not always in the most parliamentary language, from the type, as we have paid for machining the the offender. Sometimes a comparatively puerile ordinary impression of thirty-two pages; or, in question evokes an elaborate reply, or an incorother words, it costs as much to work off a small rect answer leads to an interesting controversy. sheet as a large one. As it became necessary to This picturesque variety constitutes the chief give additional space, it was also necessary that charm of the ENGLISH MECHANIC. In the House the size of the page should be increased. of Commons, any member has the right to ventilate his own opinions on any special subject, and BY A FELLOW OF THE ROYAL ASTRONOMICAL we have frequently been surprised to see a poor SOCIETY. speaker on his legs "in that oldest temple of (Concluded from page 649, Vol. X.) During the past fortnight we have received, in response to our invitation, many suggestions for the improvement of Our Journal, with some of Our readers will be glad to know that for some time past the ENGLISH MECHANIC has been increasing its circulation and its influence week by week. It circulates at the present time not only more than any scientific publication in this country, but more than all of them put together. This is authoritatively stated. It is right that our cerrespondents should know to what a large number of readers they speak, and that our advertisers should also know to what a large constituency they appeal. TIME. which we shall comply. More than one has suggested that the contents of each number be manner to almost empty benches. Take away placed on the outside page. This we have done. his right to do so, and you immediately vitally by this time prepared to learn, is to observe the self, the use of which, as the reader will be As it may be expected, different readers and impair the value of the house as a consultative sage of Celestial objects over the Meridian, either for pascorrespondents are desirous that their favourite and representative assembly. As in the House of obtaining the time or determining what is called subjects should receive more especial treatment. Commons so in the ENGLISH MECHANIC. Some-Right Ascension. The way in which observations If we complied with such requests we should favour times, it may be, a somewhat illiterate man asks are actually made is this. Just before the exsome at the expense of others, and so to some what may be supposed by many readers an un-pected time of transit of any given star, the teleextent prevent the primary object we have in view important question. But it is not unimportant scope is elevated, by means of its altitude circle -that of providing the largest amount of useful to the asker, and possibly to thousands of others and level, to the height proper for its perception. information for the largest number of readers. similarly situated. If, then, the well-informed Now what the observer has to do is to note with It should, however, be borne in mind that will be tolerant of the ignorance of their brother all imaginable accuracy the instant of the star's the ENGLISH MECHANIC is to a large readers, sympathise with them, and do their best passage over each of the wires, and this he does extent what its correspondents make it. Its to enlighten them, the fundamental purpose of by listening to the beats of the clock whil subscribers may be considered as members this journal, under, its present management, will regarding the star, and we now see the impor of a vast mutual improvement society, who consider it a duty or tance of the clock having a clear sharp tich. a privilege to instruct As it will very rarely happen that the star each other. One person asks for information on beat, we have to estimate the fraction of son Lad. exactly on a wire at the exact instant of the icck's some particular subject, and another person, This is done by comparing its distance several hundred miles away, it may be, sends it, wire at the beat before it crosse not only without fee or hope of reward, but at his Several years since, when passing through the distance at the beat after it crosses it. Reference own expense. He, however, has the satisfaction streets of Liverpool, we were accosted by a pretty to Fig. 6 will explain this. of knowing that his letter, suggestion, or recipe | little girl. We shall never forget her bright stars Remembering that as the tele copa ing may be of benefit to thousands besides the one blue eyes, and her hair, which fell like woven sun-right-hand side, and to leave it on the l seem to come into the who specially asks for the information. The beams over her shoulders. This pretty little if we imagine that, in the Zure, a freedom in the world's spending inke way WE must, however, return to the Transit it be answered. Every correspondent may con- m the it, with tha involving the union and having entered at the righthand side is at a at the 17th second of any given minute, and at bat the 18th, then we should estimate that it was on the wire itself at 17.88. Or, again, if it were at at 52, and at d at 53, we should put down its timeof crossing the wire as 52 58., and evidently the higher the power employed, the more rapid will be the apparent motion of the star, and the more accurate these subdivisions. The object of observing stars between the two horizontal wires couple of examples-and, first, At what hour will he called attention was that combustion took is that all transits should be taken over the same parts of the vertical ones. Supposing, then, that the hour, minutes, seconds, and fraction of a second at which one star was upon each of the five wires is noted, all we shall have to do is to add the five observations together and divide the result by 5 to obtain the instant of the star's passage over the central wire, which, if the instrument be in adjustment, will coincide with the meridian. In the case of the Sun, Moon, and Planets, which present sensible discs, as of course it is the passage of their centres over the Meridian which is the phenomenon to be observed, the mode adopted being to take the time of passage of the west or preceding limb over all the wires, and then to do the same with the east or following limb, the mean of these two sets of observations being evidently the instant of the transit of the centre or the body we are observing. The “Nautical Almanac" gives the Right Ascension (or distance in sidereal time eastwards of the Vernal Equinox or first point of Aries) of 148 standard stars, as well as that of all the members of the Solar System; so that, as our Sidereal Clock marks, or should mark, Sidereal Noon, or Oh. Om. Os. when this first point of Aries is on the Meridian, we have only to compare the observed time of passage of any given Star, &c., with its Right, Ascension, as given in the "Nautical Almanac,' to find out the Error of the Clock. It will further be instantly seen that a comparison of the Clock Errors day after day will give us the Clock Rate. An actual example of a transit, taken at random from our Transit book, under the date of the 9th of October, 1869, will exemplify a good deal that we have been saying: 44.3 Meridian. Turning this into Solar time by the chemical action we finally obtain 14h. 20m. 21-4252s. as the 27.9 120.5 .2 20 37 36 10 +36.38 It will be noticed that instead of adding up the whole of the five observations, and dividing the result by 5, we have merely added the seconds 2 together and multiplied the result by 2; 1 10 thing being obviously of it. The only precau 5 tion necessary is to add or subtract as many fifths of a minute, or 12 seconds, as shall make the result correspond with the number of seconds shown at the middle wire; because in reducing a really good observation, the decimals of second are all that we need take account of. never seen it. Into the adjustment of the Transit and the of any corrections to be applied to its indications, we shall not here enter. Should the want of information on these points be felt, and the desire for it be expressed, we might at some future time perhaps, enter fully into detail on this subject. As it is, we feel that in giving directions for making these adjustments and corrections, we should be addressing a very limited public indeed, and occupying precious space, which we have already considerably trenched upon. Our present, and we would fain hope not wholly unsuccessful, endeavour has been present in a simple form an e position of the mode in which the succession xf natural phenomena is made subservient to the purpose of the equable subdivision of Time; and so, more by the method of illustration than in a merely didactic way, to remove some of the vagueness which attaches to popular conceptions on this subject. It may however, have occurred to any one who has carefully followed us so far, suppose that we do get the exact error and rate of a Clock, as far as Sidereal time is concerned, what use can we ake of this when we have got it? Well, Mean Selar time can, by an easy process, be derived immediately from Sidereal; but perhaps the simplest way for a beginner is to compute the mean time of Southing of the object he proposes to observe; be can then compare its transit directly with nary Clock. This is most simply effected by place in several different forms; tha: there were The By on Monday, the 13th inst., is as follows:-" Use the following rule. From the Right Ascension of the ON THE PHENOMENA OF COMBUSTION. Vapourised. Every pound of boiling water re lanet, as the case may be (adding, if nery, 24 hours), subtract the Right Ascen of the Sun at the previous Mean Noon, given in the "Nautical Almanac" at p. II. of Ο SPECIAL REPORT. N Monday evening, March 6, in the Lecture onth under the head of" Sidereal Time at Theatre of the Society of Arts, the first Noon." The remainder will be the Side- of a series of four Cantor Lectures on Combustion 1 hours, minutes, and seconds after Mean Noon was delivered by Dr. Benjamin Paul, F.C.S. it which the body in question will cross the He first showed that combustion was generally a quired 966 units of heat for converting it into steam, or just five and a third times as much heat as was requisite to raise the temperature of a pound of water from the freezing to the boiling point. The lecturer then alluded to the relation ship between heat and mechanical energy, and in doing so briefly traced the history of the mechani cal development of heat from the production of |