MECHANIC Seas, inland, temperature and physical Seasoning pear-wood, 415, 517 Seat: Hollis observing, 146; sliding, for Seaweed, extracting iodine from ashes of, Seaweeds, 572, 646 Secondary: batteries, 189; reflections, 273 Sector, radius of, 313, 339, 363 Seeds: 469; dispersion of by winds, 540; Selenographical, 172, 277, 540 Self-deception in observation, 447 Semi-diurnal arcs, 9 Sensitive flames, 217 Separating lenses, 674 Serpents, venomous, 198, 340 Setting: lathe, 48, 129, 154, 180, 670; Seven-keyed tuning-fork, 569 Sewage cement from, 241; question, Sewing-machine, 103, 410, 417, 465; com- Shafts: hardening steel, 517; strength of, Shilling, suspended, 365, 390, 414, 439, 517 Ships: rolling of, 613; suggestions for Shoemaking, boot and, 309, 335, 385, 573, Sigma" as a "searcher after truth," 352 Signals, distant on Midland, 541, 621, 667 Silk: cleaning plain blue, 387, 440, 491; Singer new family sewing-machine, 172 Single v. double cylinder engines, 619 Skeleton flowers, 599 Skeletons, 182 Slops, hops and, 484 Small-pox, prevention and cure of, 102 Smell: 294, 344; of paint, 365, 390, 491 Smoky chimney, 261 Snatchblock, improved, 346 Soap: boiling, 77; dry, 544; Marseilles, 79 Socket handles, 671 Soda-water, 573 Sofa, stuffing for, 74 Soft eggs, 492 Softening spring water, 470 Solariological, 61 Solder: for Britannia metal, 183, 207; Soldering: flux, 627; iron, 75; iron, hot, Solid, liquid and, 389, 414 Something wrong: with Jupiter, 223; Sound: deadening, 157, 182, 206; echo of Sounding-lines, deep-sea, Sir W. Thom- Sounds of muscles and the cars 485 Sovereigns, defaulting, 57 Spanish language, 673: pronunciation, Sparks, electrical, 42, 62, 157, 228, Specific gravity: apparatus for determin- Spectacles: orange coloured, 612; suit- Spectroscope: 310; adjustable for disper- Spectrum: colours, 262, 286, 338, 361, 387; Specula, 638 Speculum: 673; working, 257, 279 Speeding: machinery, 183, 207, 233, 284; Spherical rest, the Washington, 644 Spicules of sponge, 8 Spindle for circular saws, 13, 93 Spines, round shoulders and curved, 514 Spinning tops: 252, 307, 353, 412; and Spirits, testing beer and, 519, 570 Spontaneous combustion: 18, 70, 98, 111, Spring: beds, 105, 130; furnace, 571 Spur-wheels, teeth of, 209 Stain: and polish, red, for kitchen chairs, Atlas, Proctor's, 560, 662; depths, 109, Stars: 11; B. A. C., 508; distances of the, 485 Steam: 77; boiling by, 157, 181; 'bus, new, Steam-power, 207, 259, 361, 645; want of, Steamship, proposed large, 482 Steel: 163; annealing, 146, 181, 308; Stellar: and astronomical names, 12; Stephenson and his alleged inventions, 225 Stereotyping: 153, 206, 231, 258; brass Stinging of bees, &c., 79, 103, 129, 154, 180, Sting-proof gloves, 258 Stone: artificial, 334; coal, 408, 438; Stones, shower of, 51 Stopper, extracting glass, 48 Stopping: pinholes in lead pipes, 160; Submerged forests, 598 Succession duty, 183, 208, 233 Suggestion for postal authorities, 94 416 Sulphurous smell after thunderstorms, 645 Sun: 250, 358; and terrestrial magnetism, Sundials, 79, 103, 154, 672 Sunlight, action of on glass, 613 Sunrise curve, 98; sunset and, 536, 573, Suns, coloured, 296, 358, 383, 436 Sunset: a morning, 436, 465, 486; sun- Sunspots, 358, 406, 430, 436, 463, 485, 562, Super: for cottage hives, cheap, 433, 462, Surfaces: testing plane and convex, 567; Surgery: 104, 154, 180, 206, 307; abroad, Task for chemists, 17, 157, 232 Tea: coffee, cocoa, alcohol, and, 533; Telegraph: posts, 206; preparation of, Telescopes: sun-screen for all, 150; tests Telescopic: walking-sticks, 618; work for Tempering: cast-steel chisels, 262, 287, Tent, portable dark, 365, 389 Terrestrial gravitation, 17, 36, 74, 97, 119, 144, 172, 201, 205, 228 Test: for alum ia bread, 454; for arsenic, Testing: acetic acid, 183, 208, 234, 284: Tests: for flour, 597; ores, 17; reflector, Tetrachordon, 177, 225, 275 Textile fabrics: durability of, 220; manu- Theorem, Pythagoras's: 257; new proof : Theory of vision, 171, 278; roundabout, Thermometer: 236, 261; acid bulb, 35 Thick-soled shoe, 287, 338 Thistles, how to destroy, 379 Thought, aims and instruments of scien- Threads in gas-pipes, 519 Thunder, lightning and, 597, 650, 673 Thunder-storms: 36, 881; sulphurous Tidal: mill, 183; power, 257 Tide, utilisation of power of, 609 Timbers, durability of framed, 231 Tin: boxes to hold coppers, 332; prepara- Tinned water-bottles, 104 Tinuing and soldering, 236, 261, 285, 309, Tireing cart-wheels, 338, 363 Tires; bending, 44, 100; fixing belts on, Tones, of violin, how they may be in- Tonkes, Mr.: letters by, 38, 70, 93, 126; to Tool: another combined, 99; checkering, Tooth, nerve of a, 165 Top, spinning: 252, 279, 306, 307, 326, 353 Touch-lightener, Mackenzie's, 40 Training for bicycle races, 625 Transit instrument, wall, 640; lines, Treasury of botany, 156 Treatment of asthma, 55 Trees: age of, 598, 646; killing roots of, Tremolo: 417; on violin, 487, 519 Trigonometrical, 263, 309, 494, 547 Trigonometry, question in, 260, 309, 361, Trip: to Australia, 364; to Ireland, 339, 363 Trunk engine, 207 Truss, 493, 546 Truth, searcher after, 380; "Sigma" as, Tub butter, preserving, 181 Tubes: for meerschaum pipes, silver, 102; Tunic, stained scarlet, 547, 596 Turin, university of, 313, 339 Turkey stone cutting, 75 Turpentine and wood naphtha, 569 Type, hardening lead or zinc, 517 Valve, rotating, 320 Valveless and non-packing engine, 593 Varnishing: 88; wall-paper, 75 Vegetable beefsteak, 425; colouring Velocity of rays of light, 23; of wheels Veneers: 569; for covering walls, 298; Venetian blinds, 340, 388 234, 259; M.R.C.S." on, 196; rooms, 19; Verde antico, 120, 178, 230 Verge, fixing balance wheel on, 285 Vesuvius, recent eruption of, 272 Vine root, 443, 469 Vinegar: adulterations of, 525; detection Violet, a new aniline, 299 Violets and roses, scent from, 129 Visitors, summer, 332 Vitriol, detection of in vinegar, 273 Voltaic standard of electro-motive force, Voyage, canoe, 209 Vulcanite cells, fasteningto glass, 21 WAGES, calculating, 595, 644 Walls: colouring, 157; concrete, 23; Waste material, utilisation of a, 482; of Watch: fastening escape-wheel in lever, 657 Watch-chains, fastenings for, 530 Watchmaking: 44, 205, 388, 596; and iso- Watch-plate, restoring colour of, 491 Water-floats, 156 Water-glass: 259, 547; as a preservative Water-wheel: 20, 75, 156, 206, 258, 336, Waves: action of oil on, 598, 623; mea- Weir's sewing machine, 649 Weirs, discharge of water over, 183, 208, 234 Welding cast iron, 155 Well, the deepest, 379 MECHANIC Westinghouse atmospheric railway brake 295 What is guano? 5 Wheels: 670; carriage, 346; cutlers', 47, Where is the water gone to? 226, 328 Whitechapel, spots on, 571 Window-sashes, fastening loose, 152, 199 Winter's electrical machine, 545 Wire: covered, 23, 45; purifying zinc, Wire-covering machine, 268, 381, 407, 433 Wiring garden walls, 383 Wonderful gun-barrel, 38, 356 Wood: cementing iron in, 235, 259; dis- Woods used in shipbuilding, 400 Woolwich infant, the, 562 Words, much experience in few, 250 Worms: for fishing, 311; in pony, 600, Worthlessness of beef tea, 191 Wortley, Colonel Stuart, emulsion pro- Wounds, simple method of healing, 302 ILLUSTRATIONS. Bellows, water, 410 Bell's patent feed-water heater, 26 Bells, electric, 182 Belts, fixing on tires, 102 Bending tires, 44, 101 Bicycle handle, simple way of fitting, 177 Blowing apparatus; hydraulic, 648; self- Boats, sliding seat for racing, 372 Boiler for model steamboat, 258, 259 Boilers, recent improvements in English Boiling by steam, 181 Book, using without hands, 19, 127, 224 Boring and mortising machine, 216 Boundary line, drawing, 77 Bucket, Fairbairn's ventilating, 259 Burner, handy atmospheric, 567 Butterflies and moths, setting, 266 EBDY'S patent gas-stove, 402 Eclipses of sun as seen from Jupiter, 176 Electrical machine, the Holtz, 90, 398 Electro-metallurgy, 502 Engine: non-packing valveless, 595; Equatoreal, the, its use and adjustments, Euplectella, 541 Expander, chest, 389, 414 Explosives, ignition point of, 566 FACULÆ, solar, 302 Fairbairn's ventilating bucket, 259 Filter, cheap water, 87 GARDEN: gate, 46; walls, wiring, 333 Gaslighting: automatic, 325; electro- Gassendi: 177, 277, 437; central hills in, Gas-stove, Ebdy's patent, 402 Gate, garden, 46 Gauge for bit-braces, 325 Geocentric longitude, 101 Geometrical, 443, 546, 648, 649 Glass-blowing, 364 Glasses, musical, 103 Glazing, improved method of, 38, 124 Governor : Allen's patent, 373; Sim- Gravitation, terrestrial, 17, 229 Gravity action of, 616; specific, ap- Greenhouses: hints on the construction Guns, greatly elongated projectiles for Gyroscope: 509; properties of the, 582 HAMMER, tilt, 128, 31 Handle, bicycle, simple way of fitting, 177 Hardening steel shafts, 517 262; reeds, 324 Harp: 668; improved Eolian, 540 Herodotus and Aristarchus, 406 Hints on the construction of greenhouses, Hoist, light shifting, 572 Holtz's electrical machine, 90, 398 Houses, timber, 341 Howe sewing-machine, 329 Hydraulic governor, Trotman's, 581; Hygrometer, 573, 596 IGNITION point of explosives, 566 Incubator, improved, 436 Indian pellet bow or golail, 255 Instrument: for constructing transit lines, 121; wall transit, 640 Iron and steel, magnetisation of, 229 MACHINE: aërated drink making, Mance's method of measuring internal Mandril, lathe-head, 287 Maps, weather, 451 Marine aquarium, 589 Mathematical question, 152 Mechanism: 455, 479, 532, 554, 584, 609, 633, 660; for ringing bells in model Medical coil, 597 Metal, casting in air-tight moulds, 124 Microscope: drawing from the, 506; ob- Miners, safety-lamp for, 217 Monochord with soundboard, &c., 618 Motive power for amateurs, 80 OCEANIC circulation, Gulf Stream Oil-can, improved pattern, 299 Ornamental slide-rest, 665; turning, 69, PACKING rings of piston, 415, 493 Pantagraph, 311 Paper, silvering, 191 Parallelogram of forces, 515 Pattern, wave, 649 Patterns, tool for describing, 98 Peas, mice eating, 441 Pedal, harmonium, 262 Pedals, radiating or concave, 43 Peronospora infestans, 653 Perpendicular shaft, turning, 75, 153 Perspective, 509, 560, 594 Photographic: laboratories, 477; lenses, Photographs, enlarging, 624 Pianoforte construction, 95, 591; strings, Pipes, proportions of, 35 Piston, packing rings of, 415, 493 Plato, 198, 384, 411 Pneumatic, levers for, 328 Polariscope, 365 Portable dark tent, 389 Potato discase, the, 653 Press: bookbinder's, 623; hydraulic, 286, 310 Projectiles for rifled guns, greatly elon- Proof of the deluge, one, 175 Puddling machines, 83 Pump centrifugal, 419, 470; portable Punching machine, improved, 321 QUERY, geometrical, 648 RABBLE, Dormoy's revolving, 213 Radiating pedals, 43 Rainbow, iris or, 596 Reducing valve, self-acting, 399 Reeds, harmonium, 324 Reflection and incidence, angle of, 205, Refrigerator, dynamic, 428 Removing old paint, 168 Repairing the watch, 503, 529, 580, 657 Resistance of Voltaic cell, Mance's method Rest: ornamental slide, 665; Washington Robin Hood sewing-machine, 355 Rotary: engine, 462; motion, new method Rotating valve for steam-engine, 320 SAFETY-LAMP for miners, 217 Sewing machines: 417: combined knitting Shaft, turning perpendicular, 75, 153 Shoe, thick-soled, 338 Shoemaking, boot and, 573 Show-stand 547 Sight, a question of, 20 Signals, distant, on the Midland, 541 Silvering paper, 191 Simmonds' governor, 34 Singer family sewing-machine, 172 Sketching from Nature, 520, 547, 570 Tenoning machine, 476 Terrestrial gravitation, 17, 228 Testing bleaching-powder, 236 Time at the Antipodes, 234, 337 Tires: bending, 44, 101; fixing belts on, Tool: another combined, 99; for describ- Tooth, new reptile, 203 Transit instrument, wall, 640; lines, Traversing screw chuck, 150 MECHANIC WALL transit instrument, 640 Watch-chains, fastenings for, 530 Weather: connection between colliery Wheels, improvements in carriage, 225 YACHT building, 416 THE ENGLISH MECHANIC AND WORLD OF ARTICLES. THE PRESERVATION AND DESICCATION OF WOOD. THE THE preservation of timber is a subject that has occupied the attention of scientific inquirers for years, and notwithstanding that iron has supplanted it for many purposes, wood is still used to an extent which makes its duration a consideration not to be lightly passed over. On p. 324 of our last volume we gave an account of the results of some experiments tried with various antiseptic preparations on green oak, by Herr Muller, from which it appeared that the best method of preserving wood from the effects of moisture is to force into it two mineral antiseptic salts, which mutually decompose each other in the pores of the wood, and by coagulating the albumen, and excluding the water, prevent decay. The two salts found to give the best results were phosphate of soda and chloride of barium, in solutions of which the timber was steeped; but a combination of soda, soap, and sulphate of copper is probably equally efficient, and this latter process is to be preferred for timber likely to be subjected to the attacks of worms, which under certain circumstances neces The has been found effectual with elm, poplar, alder, beech, birch, and other porous-grained timber when newly felled. He employs a solution of sulphate of copper (1 to 100 of water), and a water-tight cap being fitted on one end of the log to be preserved and connected by a tube with the tank containing the solution, which is elevated about 40ft. from the ground, the sap runs out at one end as the preserving fluid enters at the other, the weight of the liquid in the tank furnishing the very moderate pressure required by this system. Some interesting particulars of the various plans hitherto adopted for the desiccation of wood, have been recently published by M. Payen in the Annales de Conservatoire. From these we find that the methods heretofore employed in the desiccation of wood may be referred to one of the following classes :-1. Coatings applied to the surface of wood in order to prevent the access of air and moisture. 2. Simple immersion in an antiseptic fluid. 3. Vital suction or filtration, of which the Boucherie process mentioned above is the type. 4. Injection of antiseptic fluids, in a closed vessel, by alternation of vacuum and pressure. 5. Artificial desiccation, followed by injection in closed vessels. The presence of water and air in wood is one of the principal causes of the fermentation of its organic matter, and of its consequent alteration and destruction. These changes often remove an appreciable part of organic matter containing combustible carbon and hydrogen, while the hpgroscopic water contained in the wood, in its volatilisation absorbs a part of the heat developed in combustion, thus diminishing its calorific necessity in the manufacture of glass and i metallurgy where wood is the fuel employed. In the injection of wood under pressure the elimination of the water of moisture permits the antiseptic liquid to take its place. Hence the more or less complete expulsion of the water would be useful in various ways, and would fulfil one of the conditions most favourable to its conservation. There are two methods of desiccation: the natural, by long exposure to air, under cover; and the artificial, by means of stoves or ovens. The natural process is insufficient for preservation; for however great the pains and long the exposure, there always remains a residuum of water, amounting to from 10 to 20 per cent., sufficient to cause fermentation, to invite insects, and to favour cryptogamic growths. This sort of drying is suited only to wood for carpentry or furniture; being sufficient to prevent change of dimensions or warping when removed from the action of humidity. The artificial process secures a more complete preservation, since it drives from the wood all the contained moisture; this condition cannot be maintained against the influence of the atmosphere, except by some coating impervious to moisture. On the other hand, the preparation of the wood, or its injection with antiseptic fluids in closed vessels cannot be suecessful unless the wood has been sufficiently dried, so as to allow the withdrawal of the air from the tissues. When moist wood is subjected to this process, the liquids cannot escape; and of course their place cannot be taken by antiseptic fluids. sitate the exercise of as much precaution as the decay known by the generic name of rot. best known processes, however, are those which employ creosote, corrosive sublimate (Kyanising), chloride of zinc, and sulphate of copper, all of which have been used with fair success. Kyan's process, patented in 1832 and 1836, was highly thought of at the time of its introduction, but it is now seldom used. Payne's method consisted in first forcing a solution of sulphate of iron into the wood, and subsequently introducing carbonate of soda, an insoluble substance being thus formed in the cellular structure of the wood, dried and from green wood. This comparison is easily apparatus described further on. the process when properly and effectually carried out having yielded satisfactory results. Chloride of zinc has been used in several of the Government dockyards in preserving wood for the interior fittings of vessels, which are frequently liable to the attacks of insects. But probably the most successful process hitherto adopted is that known as creosoting, in which the wood is completely impregnated with oil of tar, the bituminous portion of which enters the capillary tubes of the material, closing the pores and preventing the access of air and moisture, while the albumen is coagulated and the attacks of worms and insects generally warded off by the noxious properties of the creosote. But even this method fails to preserve timber from the ravages of the Limnoria terebrans for any length of time, as piles under water, such as those of jetties, have been found to be eaten through after about four years, although thoroughly creosoted, the preserving process appearing to be effective only so long as the external coating of the oil endured. The process, as patented by Mr. Bethell, consists in drying the wood in a chamber through which the smoke and the products of combustion of the fuel, which also heats the oil, are passed; the wood while still warm is then immersed in a bath of heated creosote, or placed in strong wrought-iron cylinders, and the preserving fluid forced into it at a high pressure. With soft woods, such as pine, but little difficulty is experienced in thoroughly impregnating the timber, but with oak and other woods a pressure of 170lb. or 180lb. on the square inch is not sufficient to creosote more than the outer inch or so. One of the simplest methods of preserving wood is that introduced by M. Boucherie, which powers. desiccation of wood fuel, it is necessary to comTo give a precise notion of the utility of the pare the quantity of useful heat obtained from made by taking for standard the mean elementary composition of some wood, say oak, and the equivalent of carbon given under the two conditions. 100 parts of dry oak contain 50 of carbon, 6.20 of hydrogen, and 43.80 of oxygen. To the calorific power of the carbon (50) should be added, (somewhat variable in different kinds of wood) the equivalent representing the excess of hydrogen above the quantity necessary to unite with the oxygen so as to form water. In oak, this excess is 0.630; equivalent to at least 1.89 of carbon. 100 parts of dry oak are, therefore, equivalent to 50 +1.89 51-89 of pure carbon. = But in order to determine the quantity of useful heat, it is proper to deduct that which, in the process of combustion, transforms into vapour the hydrogen and oxygen. This water of composition is fifty-hundredths of the total weight absorbing in transformation into vapour at the temperature of combustion a quantity of heat equivalent to 5 of carbon, which is to be deducted from 51-89; giving a remainder of 46-89 of useful carbon, which represents the calorific power of 100 parts of dry oak. Now suppose that moist oak contains 45 per cent. of water: As 100 parts of desiccated wood represent 46-89 of carbon, 55 would give 25.79 of carbon; from which is to be deducted 4.50 used in vaporising the 45 parts of water; giving 21-29. It follows that 225 parts of green wood must be burned to give as much useful heat as 100 of dry. But besides this loss, it happens that in certain cases, as in the melting of glass and of zinc, it is impossible to attain the desired end by the use of green wood. Hence, desiccation, almost always useful, becomes an absolute Experience has shown that injection in closed vessels is practicable only with woods sufficiently dried, and this explains the invention of so many apparatus for desiccation. It is only within a few years that this preliminary desiccation has become successful; a success mainly due to the Attempts to desiccate wood have been frequently made. Wollaston and Fourcroy recommended the process; and Newmann employed steam for the purpose. Placing the wood in a large wooden box, he admitted steam from a boiler and drew off the condensed vapour charged with albumen and less the wood was taken out. This method would the liquid drawn off; when this became coloursap. The progress was tested by the colour of have given favourable results if superheated steam had been employed so as thoroughly to permeate the wood; but the expense would have been too great. In 1837 M. de Mecquerem invented a process which consisted in subjecting the wood to a current of heated air in a closed vessel; the current being impelled by a blower. The air entered at the bottom and escaped at the top. In 1839 M. Carpentier patented an invention in which he made use of a hermetically closed chamber, in which the wood was exposed to the action of air heated by passing over metallic plates, and introduced through four longitudinal tubes disposed upon the floor of the furnace, from which it was discharged into the heating chamber. The vapours and the moist air escaped by four longitudinal pipes placed in the upper part of the furnace and communicating with the chimney. In 1848-1853 Bethell, who gave much attention to the preservation of wood and vegetable substances, took out a number of patents in England and France. One of these consisted of a rectangular brick chamber, with hollow walls filled with cinders to prevent radiation; the arched roof being constructed in the same way. One end was left free to admit a carriage on rails, and a double iron door closed this entrance when the |