Oldalképek
PDF
ePub

Class 1. Mining and Mineral Products.

cases, as in the diamond, the usual crystalline forms exhibit a more or less complex scries in themselves. The principal colours of the gems are white, as opal, which is milk white; grey; black; blue, as some sapphires, which are Prussian blue, or the variety corundum, called ceylonite, which is indigo blue; green, as emerald; yellow, as topaz; red, as some zircons, garnets, ruby, &c; and brown, as zircons.

The varieties of colour in pearls, extend from white and lead grey, through yellowish and pink, to black; the latter being, however, remarkable and rare exceptions, and the bluish or lead grey, being less valuable than more distinct tints. Some pearls exhibit much play of colour.—D. T. A.]

Jamieson, George, 107 Union Street, Aberdeen
Proprietor.

Cairngorm stones from Cairngorm, Aberdeenshire, in the natural state, and cut into gems for jewellery.

Aberdeen and Peterhead granite, cut and mounted in brooches and other fancy articles, as buttons, studs, desk seals, pen-holders, &c.

A ram's head mounted in silver, as a snuff-box.

Scotch pearls found in the rivers Don, Ythan, and Ugie, Aberdeenshire. The shell from which the pearls are obtained.

[The Cairngorm mountain, one of those forming the granite nucleus of the Grampians, and rising to the height of 4,080 feet, is well known, and has been long celebrated for the fine quartz crystals of white, pink, dark brown, and black colours which take their name from it, and are found either in the cavities in the rock or the debris of rivers. Of these crystals, the deep yellow varieties, when well cut and set, are sold as topazes, and sometimes called Scotch topaz, while the darker varieties are called smoke topaz.—D. T. A.]

Dinneford & Co., 172 Neu> Bond Street— Inventors and Manufacturers. Specimens of magnesian minerals, and chemicals. Samples of Dinneford's pure fluid magnesia.

[The principal minerals, of which magnesia forms an important part, are the sulphate (Epsom salts), the carbonate (magnesite), the silicate (meerschaum, talc and serpentine), and the carbonate of lime and magnesia (dolomite). From any of these may be obtained the hydro-carbonate much used in pharmacy (magnesia alba), and also the earth magnesia (prot-oxide of magnesium); but they are chiefly manufactured either from the carbonate or sulphate.—D. T. A.]

Higuley, Samuel, Jcn., 32 Fleet Street
Collector and Preparer.
Sulphur Minerals.

1. Native sulphur in rhombic crystals from Sicily.

2. Native massive sulphur.

3. Native earthy sulphur.

4. Iron pyrites, or sulphuret of iron, from Cornwall, &c.

5. White iron pyrites, from Littmitz, near Carlsbad.

6. Radiated pyrites, from the chalk of Surrey and Isle of Wight.

7. Cockscomb pyrites from Derbyshire.

8. Copper pyrites in crystals, from the Banat, &c.

9. Copper pyrites massive, from Staffordshire, &o.

Crude Sulphur of Commerce.

10. Crude Sicilian sulphur.

11. Crude drop Bulphur.

Refined Sulphur.

12. Lump sulphur.

13. Boll sulphur.

14. Sublimed sulphur.

15. Sulphur vivuni.

16 and 17. Sulphur precipitation, pure and (17) adulterated.

Crystallized Sulphur.

18. Crystals of sulphur from its solution in bi-sulphide of carbon.

19. Crystals from solutions of sulphur in camphine, made at temperatures varying from 77° cent. = 170"6° Faht. to 138° cent. = 280-4° Faht.

20. Crystals of sulphur deposited from sulpho-pentachloride of phosphorus.

21. Crystals obtained by the fusion of sulphur.

[Sulphur occurs native, in rhombic crystals; also massive with earthy and bituminous impurities, and occasionally with arsenic and selenium. It is generally found in volcanic districts and near hot Bprings in formations of various geological date. It occurs abundantly with iron and copper (iron and copper pyrites), and also with the common ores of lead, Ac. It is used in chemical manufactures and in medicine; also for matches and gunpowder; and in preparing vermilion, Biilphuric acid, vulcanised caoutchouc, 4c. About 80,000 tons of crude sulphur are annually furnished from Sicily.—D. T. A.]

Cowie, A., & Rae, W., Ellon, Scotland— Proprietors. Pearls from the river Ythan, Aberdeenshire.

Rock, Mart, 6 Stratford Place, Hastings. Ornamental stand, formed chiefly of a species of grass which grows on the cliffs at Hastings, and is used for ladies' work-baskets, table-mats, &c. The stand contains specimens of Hastings pebbles.

[The Hastings pebbles are from the calciferous grit of the Tilgate beds which form the "White Rock" of Hastings, but are often elsewhere seen in more tabular masses, resting on a very compact conglomerate, enveloping large rolled pebbles of variously coloured quartz, and jasper and smaller ones of pure white quartz and flinty slate.—D. T. A.]

Dyer, William, Little Hampton, near Arundel

Proprietor and Inventor.

Sussex coast agates, found on the sea-beach; many

containing specimens of petrified sponges, sea anemones

(Choanites Konigii), and other zoophytes. Specimens

fashioned and polished for ornaments.

Model of a mechanical contrivance for ventilating rooms and public buildings.

[The agates on the Sussex coast are, to a great extent, if not entirely, chalk flints in a peculiar state; and they frequently exhibit very beautiful indications of organic structure. The definition of agate generally in mineralogy has reference to an apparently banded structure, or concentric arrangement of silicious matter, often showing different tints of colour. When of considerable size, the central part is generally clear. The essential material is, in all cases, silica, and the colour is, no doubt, due to metallic oxides, chiefly of iron and manganese.— D. T. A.]

Howard, Thomas C. E., Bristol. Collection of sands, clays, building stones, marbles, coals, minerals, and metals, belonging to the Bristol basin. This district includes, in a comparatively small area, a wide geological range, extending from the Silurian rocks up to the oolites, with some alluvial and diluvial deposits. Maps and sections illustrative of the position and localities of the specimens are exhibited with them.

Breadalbane, Marquis of, Taymouth, Aberfeldy, Perth—Producer. Slates from the quarries of Easdale, &c, in Argyllshire.

Four squares of flooring, showing specimens of some of the woods grown in Perthshire and Argyllshire. Table, chair, and chest of drawers, veneered with roots of the natural Scotch fir, dug from peat bog in the forest of Glenorchy, Argyllshire.

Class 1. Mining and Mineral Products.

Specimens from the copper mine of Toinnadashin on the south side of Loch Tay, Perthshire.

Specimens from the silver-lead mine of Corriebuie, on the south side of Loch Tay, Perthshire.

Specimens from the lead mines of Tyndrum, Perthshire.

Chromate of iron, from the mine of Corriecharmaig, in Glenlochy, Perthshire.

Hssmatitic iron, from Qlenquaich, Perthshire.

Rutile, or oxide of titanium, from the north side of Loch Tay, Perthshire.

Brown quartz, from Ben-Lawers, north side of Loch Tay, Perthshire.

Granite and porphyry, from the forest of Glenorchy, in Argyllshire.

Granite, from the quarries of Barrs and Inverliver, on Loch Etive, Argyllshire.

[The Easdale and other slate quarries of Argyllshire which have been worked for upwards of three centuries, employ about 200 men and boyB, and export about 10,000,000 of slates annually, in about 300 vessels. The slates are not obtained generally in very large slabs, but most of the quarries supply a fair proportion of the larger kinds, used for roofing, and measuring 2 feet by 12 inches (Duchesses). They are worked in Easdale, Seil, and other small islands of clay slate, a little south of Oban, and near the large island of Jura. The quarries are of various dimensions; that of Ellenabeich being 300 feet long, 100 feet deep, and 150 feet broad, the ^quality improving in the depth. The other quarries are smaller; but those of Easdale are very valuable, and the quality excellent. The stratification of the beds of slate rocks is very much disturbed, but the cleavage is invariable, running N.E. and S.W., and dipping 50°.

The mineral produce of Perthshire, illustrated above, is obtained from systems of veins, some of which, running N. W. and S.W., contain copper ores of various kinds, with some ores of iron; and others, running N.N.E. andS.S.W., contain chiefly lead ore. The veinstone is generally quartz, and the ores include several interesting minerals.— D. T. A.]

Lance, Edward Jarman, Frimley, Bagshot,
Surrey.

Specimens of minerals, in their raw state, as used in the arts (as iron from the Wealden formation, and the coal measures, &c), arranged in trays, and named.

Specimens of minerals, used as manures, as phosphate of lime and magnesia; sulphate of lime and alumina; Cornwall sand, shell marl, &c.

Specimens of cultivated soils or earths, arranged as they occur from London to Cornwall, being the abrasions of minerals.

Specimens of corn produce; the effect of the admixture of fertilizing minerals and culture on silicious sand, in illustration of the preceding collection.

Richardson, Thomas Wareham, Brede, near tfortham, Sussex. Specimen of silicious stone found in the parish of Brede, Sussex; useful for sharpening edge tools.

[The Btrata around Hastings, and extending to Brede, consist of the Hastings sand, which is the principal and middle formation of the Wealden series. Amongst the sands are beds of Tilgate stone, consisting of very hard sandstone, embedded in sand, and having, in some cases, a sub-crystalline structure. These are often used as whetstones, and are of good quality.—D. T. A.]

Cassels, Alexander, Edinburgh— Proprietor Two curling stones usod in Scotland in tho national

game of curling, made of the rock of Ailsa Craig, in the Firth of Clyde.

A specimen of the rock in the rough state.

The game of curling is practised upon ice during the winter. The Royal Caledonian Curling Club, of which His Royal Highness Prince Albert is patron, is composed of above 10,000 members.

[Ailsa Crag consists of a single rock of grayish compact felspar, with small grains of quartz, and very minute particles of hornblende. The height is stated to be 1100 feet, its length 3300, and its breadth 2200. On the east it rises by steps, but from the south, round by the west to the north, it is more perpendicular, and divided into columns. It rises abruptly from deep water, about 10 miles west of the coast of Ayrshire, and 15 miles south of the Isle of Arran.—D. T. A.]

Gill, William Eathobne, Truro— Inventor. Normal guano, a manure: prepared from the refuse of the fisheries, as a superior fertiliser.

[The large quantities of fish, particularly pilchards, mackerel, and hake, which are caught around the coast of Cornwall, renders the preparation of a manure from the refuse, on most occasions, a comparatively easy undertaking. The value of fish manure has been long known, and it is not at all uncommon for farmers to go to considerable expense to obtain the offal from the nearest fishing towns; and they value highly the refuse salt, which they obtain after the pilchard season, from the curing-houses, on account of the great quantity of potoil it contains.—R. H.]

Oleic, M., Shetland. Various minerals.

[The Shetland islands consist chiefly of gneiss, penetrated by veins or dikes of porphyritic rock. Limestone bands occur in the gneiss, and magnesian rocks are found in the islands of Unst and Fetlar. In these, especially in the serpentine, chromate of iron is abundantly disseminated in granular particles, sometimes forming nodules weighing upwards of 1 cwt. This ore is the source of the pigments known as chrome yellow, &c. The other minerals, including copper ores, noble serpentine, asbestos, steatite, indurated talc, &c., are not Bo important. The rare mineral Brucite occurs in the serpentine of Balta Sound. It is a hydrous carbonate of magnesia.—D. T. A.]

Brodie, Peter B., F.G.S., Doum Hatherley,
6 loucester—Producer.

1. Limestone, from the Purbeck strata in the Yale of Wardour, Wiltshire, applicable to purposes of lithography.

2. Ironstone, from the top beds of the lower lias, RobinBwood Hill, near Gloucester, Hewlett's Hill, near Cheltenham, and Chipping Campden, Gloucestershire; it occurs in beds, and occupies a considerable area in the Cotswold bills.

3. Septaria, found in the upper beds of the lower lias, Robinswood Hill, near Gloucester, in sufficient quantities to be used for cement.

4. Iron pyrites, or sulphuret of iron, found in digging a well in the lias at Gloucester.

5. Limestone, forming an extensive bed in the lower lias near its base, and extending through Gloucestershire and Somersetshire.

6. Hard limestone of the lower lias, near Bidford, in Warwickshire. This stone takes a polish, and could bo used as a marble.

7. Bone bed, a thin but extensive band at the base of the lower lias, charged with fragments of bones, teeth, and coprolites, which might be beneficial as a manure. It occurs at Wainlodo Cliff, Coombe Hill, near Gloucester, Westbury-on-Sevem, Somersetshire, and Wales,

Class 1. Mining and Mineral Products.

[All the above specimens, except the first, are from the lias, a deposit of calcareous clay widely distributed in the west of England, and ranging from the coast of Darsetshire, at Lyme Regis, to the coast of Yorkshire, at Whitby. The upper and lower beds arc often shaly, and yield materials for the manufacture of alum and other substances. The middle portion is more calcareous, and includes some bands of compact limestone. Where the carbonate of lime forms into nodules somewhat argillaceous, there are found septaria well adapted to the making of cement. In many places, the iron disseminated through the clay have collected into bands of impure ironstone, which, however, is not likely to come into successful competition with other ores. The bone-bed may, if the expenses of transport be inconsiderable, be worth working as a cheap and effective mineral manure.—D. T. A.]

Goixd, Richard, White Street, Cork, Ireland. Samples of salt from rock salt pickle; manufactured by the exhibitor.

Roake, James White, Xcuhury, Berkshire.

Specimens of soils which surround Newbury, Berks, and the uses to which they are applied.

Nos. I to 4. Various clays. 5. White. 6. Red. 7. Yellow ochre. 8. Fine white sand. 9. Coarse sand. 10. Ferruginous sand. 11. Ochreous sand, used by iron founders. 12. Green sand, with oysters embedded. 13. Gravel, rough and pebbly. 14. Calcined pebbles, reduced to coarse and medium grit. 15. Fine pebbles, with stucco made from it, to compare with a coloured fragment and tessora from Herculaneum. 16. Chalk from Kiutbury, with shells peculiar to that deposit. 17. Whiting. 18. Limestone. 19. Stone lime. 20. Chalk lime, through which gas has passed. 21. Peat from the Kennet valley. 22. Peat, condensed by Cobbold's patent process. 23. Peat, pulverised for horticultural uses, and disinfecting purposes. 24. Peat ashes, for the agriculturist.

Samples of bricks, tiles, and pottery.

[Newbury is situated on the lower tertiary beds immediately overlying the chalk, which crops out at a short distance from London to the north, south, and west. The river Kennel crosses the chalk from the west, runs through the town towards the east, and enters the Thames near Reading. The tertiary deposits here include a moderate thickness of the London clay overlying the mottled clays and sands of the lower or plastic clay series, including a pebble bed, mottled red clays and sands, and the whole covered up with a little gravel.—D. T. A.]

Rei.f, S., Jlevjatc, Surrey—Producer. White sand, from the Tunnel Caves at Reigate (called in use "silver sand,") dug from the rock.

Rock, James, jun., Hastings.

Lignite found in the summit tunnel of the Hastings and Ashford railway, 1} miles to the N.N.K. of Hastings, about 90 feet from the surface, and 300 feet abovo the sea level. The strata dip from N.W. to S.E. at an angle of about C»5 degrees.

Clinker, containing a considerable quantity of iron, from an ancient cindor-bank ou the property of Hercules Sharpe, Esq., Sedlescomb, Sussex.

Claystone, said to contain oxide of chromium.

Fine white sand, from Hastings cliffs.

[The lignite of the Hastings sand formation, near Hastings, has been long known, and corresponds in every particular with other lignites from Tilgate Forest. It occurs in nearly horizontal bands, thinning out into a mere film, and the largest masses do not exceed a few inches in thickness. It is very brittle, and bums with a bright flame; resembles jet, and contains included frag

ments of ligneous character. It is not unlike the Bovey coal.

Ironstone was formerly extracted from some of the ferruginous sands of the Wealden, either in irregular concretions, hard, compact, and of steel-grey colour inside, or laminated, and often concentric. In some plates it is of excellent quality, and when the country was covered with forest was much used in the manufacture of charcoal iron.—D. T. A.]

Nixon, Rev. Alexander, Xathfeld, Dunfanaghy, Duncjal, Ireland—-Producer. Steatite—from the Conyingham-Denison property; found in large masses on the seashore.

Slate (found within tight feet of the surface) from Ballyboes quarry, recently opened.

Sand, from Muckiah mountain, within five miles of Sheephaven on Ballyness. A pure silicious sand producing a clear flint glass.

Inclis, Jons, Smerick, by Buckie, Banffshire, Scotland— Proprietor. Relics of antiquity, being two pieces of flint, finely polished, and brought to thin edges at their ends. Found by the exhibitor 15 inches below the surface of the ground, and two feet apart, on his farm, in a yellow clay subsoil.

Flather & Hades, 1 Caitle Hills, awl 2 Broad
Law, Shifftell.

Prepared Trent sand, or wharpe, used for buffing up, or bringing to a surface, German silver, Britannia metal, brass, copj>er, &c.

Prepared Welsh rotten-stone, used for producing the fine polish on silver, Britannia metal goods, &c.; when mixed with one-sixth its weight, of rape or sweet oil, it forms the polishing paste used for cleaning Britannia nietal, brasses, tin ware, and other blight metal goods.

[Most substances employed under the name of rottenstone, or Tripoli, are essentially composed of silica in a peculiar state of subdivision, the actual particles of which the whole is made up being crystalline, but the mass earthy, and often reduced by compression to a solid state, having a slaty fracture. In most cases, the origin may be traced to the remains of infusorial animalcules, and occasionally the presence of carbon, and a little resinous organic matter which shows this still more clearly. The name Tripoli is generally understood to apply to all the earthy varieties (of which there are several) in which silica exists nearly pure, but in a very minute state of subdivision. Rotten-stone is limited to those which are light and friable, and of very fine grain. It occurs rather abundantly near Bakewell, in Derbyshire, amongst tho carboniferous limestones, but is often met with in other rocks.—D. T. A.]

Prepared lime, used for producing the bright black polish upon German Bilver, electro-plated, and silver goods.

Cawley, James, Pendell, Bledingley—Producer
and Manufacturer.

Stone from the surface of fuller's earth, used for building purposes.

Fuller's earth in the raw state, blue and yellow.

Fuller's earth, blue and yellow, dried and prepared for use in the manufacture of woollen cloths, flannels, blankets, Scotch tweeds, and tartan shawls.

Specimen of the spar found in the strata of the fuller's earth.

All the above specimens were found and dug at Mr. Cawley's pits at Nutriold, Surrey.

[The fuller's earth pits of Nutfield, near Reigate, are extensively worked, and supply large quantities of this substance to the clothing districts. There are two kinds, one greener than the other, owing to the presence of silicate of iron; but both exist under the same geological conditions, occurring in the lower Cretaceous series, and differing little in chemical condition.

Class 1 . Mining and Mineral Products.

Fuller's earth consists of about 45 silica, 20 alumina, and 25 water. When placed in water it almost dissolves, and when exposed to great heat it melts. It combines readily with grease, forming a kind of earthy soap, and for this reason is valuable in the manufacture of cloth made of animal fibre.—D. T. A.]

Gawkroger & Hynam, 7 Princes Square,
Finsb'jry—Manufacturers.

Fuller's earth, and purified dried fuller's earth, from Chart Lodge, Reigate, Surrey, and Cormouger's Pits, Nutfield, Surrey.

[Fuller's earth, and its localities in England, are elsewhere described. The following is the mode of purifying and preparing the raw material for use :—

The fuller's earth, after it comes from the pit, is baked or dried by exposure to the sun, and then thrown into cold water, where it falls into a powder, and the finer parts are separated from the coarser by a method of washing in several tubs, through which the water is conducted, and where it deposits the different kinds in succession. These are used for different kinds of cloth, the coarser part for the inferior and the fine for the better kinds of cloth. The soapy combinations formed by fuller's earth with the greasy portions of cloth during the process of falling, are supposed to serve the purpose of mordants in some measure.—D. T. A.]

Lee, John, LLD., Hartwell, near Aylesbury
Proprietor.

Samples of fine washed sand, from the sand-hill in the parish of Stone, near Aylesbury.

White, yellow, blue, and green glass prisms, made from the same.

Two spheres of white glass, made from the same sand.

[These sands are from soft beds of the Lowes greensand series, of which there is a considerable thickness, forming a knoll at Stone. There is about 8 feet of whitish sand below 7 feet of sand and sandy clay, containing impure fuller's earth. The lower green-sand terminates a little to the west, and is succeeded by the beds of Portland stone, forming a distinct ridge near Hartwell, but covered and obscured by beds of gravel.—D. T. A.]

Riddell, Sir James Miles, Bart, Strontian—
Proprietor.

Various specimens of minerals.

Harmatome, in large crystals, on calcareous spar.

Morvenite, the variety of harmatome, on calcareous spar, amber colour.

Crystallized calcareous spar, with annular iron pyrites, enclosing radiated sulphate of barytes.

Brown calcareous spar.

Crystallized calcareous spar, of a pink colour.

Calcareous spar, on hexahedral tables enclosing icositetial crystals.

Hexahedral prismatic calcareous spar, penetrated with crystals of the same, of the different form, the obtuse solid angle of which partly protrudes from the terminal plane of the prism.

Brewsterite, discovered near Strontian.

Crystallized carbonate of strontian.

Massive fibrous carbonate of strontian, with heavy spar.

sulphate of barytes with phosphate of lead.

Sulphuret of iron.

Gneiss. Gneiss passing into granite. Gneiss with red felspar.

Junction of gneiss with granite, intersected by a vein of felspar.

Fine-grained granites. Syenites

Porphyritic granite.

Syenite, with a vein of felspar.

Rock, of carbonate of lime and serpentine.

Granite studded with garnets, from the summit of Ben Resipole, a mountain above 3,000 feet in height.

A very large specimen of the same.

Quartz rock.

Sulphuret of lead, in a matrix of calcareous spar, from the Smithy Vein (Feedonald district).

Sulphuret of lead with calcareous spar, a continuous string of lead ore, from the red vein of Feedonald.

Crystallized sulphuret of lead (the primary cube), from the same vein.

Sulphuret of lead, with sulphuret of zinc and crystallized calcareous spar in the cavities.

Sulphuret of zinc and calcareous spar, from Corantee.

Cubic sulphuret of lead with calcareous spar.

Sulphuret of lead in calcareous spar, from Clashgoram mine (middle district).

Sulphuret of lead; sulphuret of lead, embedded in calcareous spar; and sulphuret of lead, partly crystallized with calcareous spar—from Belsgiove Mine.

Junction of granite and mica slate.

Lias limestone; from the north side of the promontory of Ardnamurchan.

Lias limestone, from the south side of the promontory.

A large mass of sulphate of barytes, a substance constituting much of the matrix or veinstone of lead ore.

[At Strontian, in the western part of Argyllshire, a boss of granite is seen penetrating the gneiss, which abounds in the district; and a little further to the west, a large quantity of porphyry and trap occurs, covered, in two or three places uear Ardnamurchan, by deposits of the oolitic and liassic period. In the granite, and near its junction with the gneiss, mineral veins are found, containing lead and copper; and in one of these was first observed the mineral thence called strontkmitc, or strontites, a carbonate of strontide, usually associated with calc-spar, sulphate of barytes, and galena. The metal called strontian, obtained from this mineral, was first described by Sir H. Davy, and resembles barium in its properties and appearance. Carbonate of strontia is chiefly used in the production of the nitrate employed in giving a red colour to fireworks.

Harmotome and morvenite are hydrous silicates of alumina and barytes. Brewsterite is also hydrous silicate of alumina, but contains strontia, as well as barytes. The other minerals are well known. The Alias is one of several small patches round tho trap rocks of Ardnamurchan, Morven, and the Isle of Mull, and contains numerous organic remains.—D. T. A.]

Morrison, George, Agent of Earl Somera, litigate. Sand from the common, named Reigate Heath, valued for its grit, and used in the manufacture of glass.

[This sand is from certain beds of the lower grcensand series much developed in Surrey, and frequently exhibiting extensive tracts of sand, often without admixture of any argillaceous or calcareous matter.—D. T. A.]

Squire, John & William, Tnmrcorth, Isle of Wight, Hampshire. Specimen of pure white sand, used in the manufacture of best flint glass, taken from horizontal and vertical beds in the cliffs in Alum Bay, near the Needles, on the estate of William George Ward, Esq. Exported froinTamworth. Extensively used by glass-makei-s, for its silicious properties.

Class 1. Mining and Mineral Products.

Jenkins 4 Bees, Truro—Producers. Ochres, three in a powdered state, of different shades of colour, and one in lumps of two shades of colour; produced at Kea, near Truro; used in the manufacture of paints, paper-hangings, &c. Exhibited on account of their clearness, fulness of colour, body, and cheapness.

Gore, Charles William, Moreton-in-Marsh— Proprietor. Brown ochre, in its raw state, used for staining and for common purposes. In its raw state it is a stone colour, and is used for houses, glass-houses, &c. When calcined, it is of a deep brown colour, and is used for facia, iron-work, &c.; it has a Btroug grit, and requires the use of machinery to pulverize, grind, and prepare it.

Ross, Thomas, Claremont, Hastings. Iron ore from the neighbourhood of Hastings. Tilgate stone from the East Cliff, Hastings Hastings "granite" (locally so called). Clay, from a large bed lying under the sand cliffs to the eastward of Hastings. Hastings hone-stone, rough and prepared.

[The clay near Hastings underlies a thick deposit of white sand and friable sandstone, called the '' Worth beds." The clay itself contains undulating seams of lignite. It overlies another bed also including lignite.—D. T. A.]

Rogers, Samuel Sandilakds, Douglas, Isle of Man. Specimens of the earths and sands of the Isle of Man.

Potter, William, & Co., 87 Alhjate, and Cromfurd, Derbyshire—Proprietors and Manufacturers. Specimens <f fluor spar, calcareous spar, calamine, white-lead ore, lead ore, sulphate of barytes, and sulphate of barytes manufactured as a pigment. From the Dinah, Goodluck, and other mines in the vicinity of Cromford, Derbyshire.

Hill, John, Ringsend, Dublin—Manufacturer. Basket and pink salt for table use; Irish fine, or butter salt, and coarse or provision salt.

[There are no natural deposits of salt in Ireland, and the various kinds exhibited by and prepared in that country are generally procured from the English salt mines.—D. T. A.]

Rouse, Capt. & G. N. Simmons, Truro. Specimens of sands, from various parts of Cornwall, visited for agricultural and building purposes: the agricultural sands from Gwithian, Falmouth harbour, and Perran Forth; the others used for building purposes.

Collinson, Charles, Mansfield—Proprietor. Red casting sand, found only at Mansfield, and of value in the production of fine castings. Its qualities are fineness of grain, porosity, great purity and smoothness, which latter property contributes to give B high face to castings.

Brocredon, William, 29 Devonshire Street,
Queen Square—Patentee and Manufacturer.

Native plumbago:—Samples from the mines of Borrowdale in Cumberland, fine and crude: from Ceylon, Davis' Straits, Spain, Bohemia (called Mexican), Greenland, California, France (Poligny): nodules from India, &c.

Samples of Cumberland black lead, prepared for condensing into blocks by patent process.

Specimens in powder, purified from grit, and in fine powder, ready for condensing, which has passed through apertures Jj,^ th of an inch in diameter.

Blocks which have been condensed by a pressure of 5000 tons.

Slices of the blocks for pencil-makers; points for Mor<Inn's ever-pointed pencils; cedar pencils, by various makers of Brookman's patent Cumberland lead.

Blocks made of Ceylon and other plumbagos, &c.

The plumbagos exhibited in their natural state, are— Three very fine samples of the old black-lead, formerly found in Cumberland. The only native plumbago which could be cut into slices, and used in its natural state; the miners have long failed to supply such specimens. Two samples of Cumberland lead, containing too much grit to be used without purification. Samples of plumbago from Ceylon, crystalline and fibrous: this is the purest plumbago known, being 98"55 pure carbon; but it is too fragile for use in cedar. Two samples from Davis's Straits aud Greenland. One from California. Others from Spain and Bohemia (called Mexican), of these two the common pencils are made, when hardened by sulphur. From none of these can a fine pencil be made, but the Cumberland.

The manufactured blocks are from the second variety of the Cumberland, freed from grit, and reduced to an impalpable powder, of which a quantity is shown to form one of the blocks. From this powder the air is exhausted, when it is condensed in a dry state by an enormous pressure, which consolidates a mass weighing seven ounces under a force, in two blows, of 5,000 tons, leaving it as compact as the natural; and from these blocks slices are cut, as shown: these are inserted in channels in the cedar. It is also cut into the lengths of the block as square threads; these are rounded, then cut to the proper lengths for the ever-pointed pencils.

For the process by which the Cumberland lead can be freed from grit, and then solidified, the exhibitor obtained a patent, and pencil manufacturers use it only for their finest drawing pencils.

[Graphite or Plumbago, a form of carbon, commonly called black-lead, and sometimes, but incorrectly, regarded as a carburet of iron, is a well-known soft mineral, crystallized in small hexagonal plates of laminated structure, infusible, burning with great difficulty under the blowpipe, consisting of from 85 to 8"35 per cent, of carbon, and having a specific gravity of 2-09 to 2'25; the purest being the lightest. It is found in metamorphic, generally in schistose, rocks, of various geological age, in masses or veins parallel to the lamination or stratification. The pure and valuable kinds are very rare, and have been obtained almost exclusively from the localities mentioned above. The variety from Ceylon is remarkably pure but soft; that from Greenland is also pure, but very hard. The latter, according to an analysis recently made by T. H. Henry, Esq yields carbon 9G"6, ash &4; but does not seem adapted for use in pencil-making, owing to its hardness and paleness. It appears that the presence of a certain quantity of iron is favourable for its use in the arts.

The method by which Mr. Brockedon has rendered several of the softer and less compact graphites available, and has also brought into use the fragments formerly too small for pencils, is by enormous compression, produced by powerful machinery, on the finely-levigated powder in a pure state, after a certain amount of preparation.— D. T.A.]

Reeves & Sons, 113 Chea/mde—Inventors and Manufacturers. Cumberland lead and cedar wood, in the different forms in which they are used in the manufacture of drawing pencils.

Water colours, in various forms, prepared with the medium of pure wax, in lieu of gum, in order to produce permanency, brilliancy, and easy application.

Solomon, Thomas, Truro. Varieties of hone-stones, used for sharpening edge

« ElőzőTovább »