Fig. 5.-Plan view of Top of Inner Shell, &c. purpose. At the Cardiff meeting of the Royal Agricultural Society of England, 1872, Messrs. Clayton and Shuttleworth gained the first prize for their portable engine for threshing, &c.

Another class of engines, the semi-portable, is now being largely made. They take the place of, and are considered preferable to, vertical engines. Fig. 3 was awarded the first prize at the meeting of the Royal Agricultural Society at Oxford, 1870, where the merits of this kind of engine were first recognised. In its general outline it closely resembles a common portable without wheels; but in detail it differs widely. Thus the pedestal on which it rests forms a water-tank, and the flywheel, cylinder, and working parts are fixed to the boiler by a common saddle, on the top of which, between the cylinder and smoke-box, runs peculiar apparatus for heating the feed water by means of the exhaust steam, the condensed steam or water of condensation passing into the pedestal ROUND LEVEL tank below. The cylinder is steam jacketed, and the governor and expansion gear, &c., are similar to those of their other engines. The saddle is ferable to the common plan of separate brackets bottled to the boiler plate; and the pedestal water-tank adds to the stability of the engine. It is much more compact and requires less room than fig. 1 with a detached boiler, and at the Oxford trials was found superior to the vertical engines in duty and the economy of

steam.

pre

The chief improvement in the vertical steam-engine recently brought out by the Messrs. Davey, Paxman, and Co., of Colchester, is in the construction of the boiler. The boiler consists of a double shell, the fire-box being in the centre; and to the outside boiler plate the engine is bolted by brackets. The whole is mounted on a strong cast-iron bed-plate, which forms a water-tank, heater, and ashpít. Fig. 4 is a vertical section showing the outer and inner boiler-plates, the water line, bent water-tubes, and furnace. In the common class of vertical boilers a few water-tubes cross the furnace nearly on a level around which the fire plays. But in fig. 4 a great many bent, tapering tubes spring out of the inner shell, as shown in the engraving, rising nearly perpendicular from the line c D. Fig. 5 is a plan view of the top of the inner shell, showing the number of water-tubes, the deflector valves, water-line, and chimney. Only one deflector valve is shown in the cut; but each tube has a valve whose function is to deflect the hot water downwards, and thus prevent violent ebullition and wet steam, as indicated by a tube on the right-hand side of the chimney purposely without a deflector valve, to show the action of the water. A rapid circulation is kept up in the tubes and in every part of the boiler, so that its steain-gene

rating efficiency is about equal to the best multitubular boilers, as fig. 2 and fig. 3. There is a damper in the chimney for regulating draught by means of hand-screws, &c.

The other class of boilers, wholly composed of wrought-iron water-tubes, generate steam rapidly at a small cost of fuel, and they are free from the danger attending other boilers. As yet they are chiefly used for stationary work. But a pair of ploughing engines were tried in 1871, and although not equal to the common multitubular class, were not without future promise. Fig. 6 is a sectional view of the tubular boiler of the Messrs. J. and F. Howard, Bedford, on the horizontal arrangement. It is built up of wrought-iron tubes without rivets. The tubes are counterparts of each other, on the interchangeable principle; and from recent improvements made they can easily be exchanged, cleaned, and kept in order. They occupy much less space than the Cornish boilers, and can be worked at a pressure of 150 lb. to the square inch with greater safety than a Cornish one at 50 lb. It is however by using superheated steam at a high pressure expansively in the cylinder, and by variable expansion gear, that this class of boilers do the most work and effect the greatest economy of fuel and water. The fire does not rise up through the tubes, but is diverted by means of diaphragm plates circuitously, so as to utilise heat. The chimney has a damper to regulate draught. The stoke-hole, ground-level, water-line, steam-gauge, &c., require no explanation. Variable expansion gear is now used in most steam-engines

LONGITUDINAL SECTION

Fig. 6.-Longitudinal Section of Howard's Tubular Boiler.

for threshing, &c. It is generally done by altering the length of the stroke of the eccentric that works the slide valve. This

Fig. 7.-Robey & Co.'s Governor.

is done either by shifting the eccentric on the crank-shaft, or by adjusting the length of the connecting-rod to the desired cut-off. The Messrs. Robey and Co., of Lincoln, make their governor shift their eccentric on the crank-shaft, so as to lengthen or

1979 STEAM NAVIGATION; STEAM VESSEL.

shorten its stroke by means of two opposite wedges or inclined planes. The governor is mounted horizontally on the crankshaft, between the fly-wheel and crank, as shown in fig. 7: c is the crank, в the eccentric. A rectangular slot cut in the eccentric fits on a square part of the crank-shaft upon which the eccentric slides by the action of the two wedges. By this means the travel of the valve and cut-off is regulated, whilst the lead of the valve remains constant. A spiral spring on the crankshaft keeps the balls in position when at rest.

STEAM HAMMER [HAMMER, E. C., vol. iv. col. 608; and E. C. S., col. 1221.]

STEAM NAVIGATION; STEAM VESSEL. In the articles under these headings in E. C.; in STEAM ENGINE, E. C. and E. C. S.; and in various other articles referred to under SHIP, E. C. S.-will be found the requisite information concerning the substitution of steam power for sailing power in ships; the origin of the system; its growing adoption for merchant-vessels; its still more complete adoption for ships of war; the increasing preference for the screw-propeller over the paddle-wheel; and statistics of the war and commercial fleets of Britain and other countries.

STEAM ROAD LOCOMOTIVES [TRACTION ENGINES, E. C. S.].

STEAM ROAD-ROLLER. The advantages of rolling roads by steam rollers are now universally acknowledged. The reports of road surveyors and others using them are in every case in

bear differently, being applied almost directly with the weight of the roller. If, therefore, the metal is of uniform quality and evenly spread, it will be compressed into a solid body with a smooth surface, the materials being less crushed and ground to dust than by horse-rollers. If not finely broken, so as to contain grit, some gravel or coarse sand is spread over the stones, and the whole watered to make the metal "run in." When finished the road is fit for traffic over its entire breadth. When left to be consolidated by traffic the road is unequally worn, the feet of horses and the wheels of vehicles producing an excessive wear and tear upon it.

The engraving (fig. 1) requires little explanation. The engine and boiler are carried upon four rollers of equal breadths, two for driving and two for steering. The whole weight is equally divided between the front and hind rollers. The front rollers are driven by chain gear from the crank shaft, shown at the left side of the engine-driver. The steerage rollers are carried in a turntable frame, on small friction wheels in the side frame. Steering is effected by a chain passing round the turntable and worm gear from the wheel in the left hand of the steersman. The turntable permits the driving and steerage rollers to accommodate themselves to the curved surface of the road, and the machine can be turned in little more than its own length, an advantage in rolling steep inclines.

The Messrs. Aveling and Porter have this year (1873) brought out a light steam-roller (fig. 2), different in construction from

their favour as compared with heavy rollers hauled by horses, or where the broken metal is "run in" by the passing traffic. The difference is easily accounted for, and may be shown by reference to the annexed engraving of Aveling and Porter's heavy steam roller (fig. 1). Rollers of such weights could not be profitably hauled by horses, as the number required would not pull together. Again, however well they are yoked in a team, horses pull at a mechanical disadvantage so great as to render the work of rolling impracticable; for as the broken metal or gravel under their feet is the fulcrum, an open track is left when there is a considerable depth applied; and when the covering of metal is thin, it is unequally consolidated by their trampling. A long team of horses haul at an angle which is not only against their draught, but adverse to the action of the roller. Hence it is seldom that horse-rollers exceed from 7 to 10 tons, the greater number being not more than the half of this weight; and as the short teams and light rollers require to go more frequently over the metal, this accounts for the greater percentage of dust, mud, and waste of material they produce, and the open spaces they leave between the stones. On the other hand, the steam-roller applies both its weight and locomotive powers directly to the consolidation of the newly spread metal, leaving a smooth track behind for the next turn. In this case, as in the horse-roller, the roadway under each roller is its fulcrum; but the locomotive power of the engine is brought to

fig. 1. It is made of different weights under 15 tons, to meet a large demand for which fig. 1, 15 tons to 30 tons, is too heavy. It is supported by four rollers, as fig. 1, but the position of the driving rollers and steerage rollers is reversed. The steerage rollers are also of a different form, being frustums of cones on a bent axle, so that on the ground line they run close together, thereby leaving above the axle sufficient open space for the vertical shaft which connects them to the boiler. The bent axle is made fast to this shaft in the middle, and also at the two ends by a semicircular tripod-frame, and the shaft serves the twofold purpose of a support to the boiler and a pivot on which to turn in steering. The steerage is effected by two chains from opposite ends of the axle being wound on to one drum and off from another by means of a worm-wheel and worm, the latter actuated by a hand-wheel close to the foot-plate, thus enabling the engine-driver to manage both the steerage and engine. Steam is taken into the cylinder from the dome over a steam jacket in direct communication with the boiler, thus rendering outside and inside steam pipes unnecessary. The firebox plates extend upwards and backwards on both sides, so as to carry the crank-shaft, counter-shaft, and driving-axle. The two driving-rollers, which are driven by spur gear from the crank-shaft, have a compensating motion for turning or working in curves, the working parts being thus similar to those of their road locomotives. Each roller has a scraper, held to by a

weighted lever. Several of these light steam rollers are already in successful operation. They work on rather steeper gradients than fig. 1, are managed by one person, and may be used for rolling grass land when too dry and hard for horse-rollers; and as rolling wet land with the latter does much harm, the practice of rolling by steain may become general.

The history of steam road-rollers may be told in few words. Lemoine's roller was used in Paris about 1860; according to Mr. Paget's report, printed by order of the Metropolitan Board of Works, there was not one in London in May, 1870. But Liverpool has used a 30-ton Aveling and Porter roller since 1867; and the year following (1868) Manning, Wardle, and Co., of Leeds, commenced the manufacture of steam-rollers on the Ballaison construction. Since then the merits of steamrollers over horse-rollers has been closely investigated'; results in every inquiry turning in favour of the former, the general

STEEL MANUFACTURE.

1982 larly shipped to Cardiff, chiefly for the use of the Bessemer steel makers. Heaton's system and Sherman's system depend on the addition of small quantities of chemical agents to molten iron, as a means of removing or neutralising the sulphur and phosphorus, and thereby facilitating the conversion of the iron into steel. Iodine is one of the agents thus proposed to be employed; but the employment even of a small quantity of this substance would be costly, and its advantages have not yet been clearly shown. Chenot's steel does not differ much from the ordinary kind, it being made by incorporating good iron with any substance rich in carbon, such as charcoal, resin, wood-tar, or fat. Krupp's steel, like many other kinds made on the continent, is prepared in a reverberatory furnace, by a process differing but little from the puddling of iron. The Siemens-Martin process, the joint work of two inventors,

conclusion being that steam road-rolling is from 40 to 50 per cent. cheaper, and better in every respect, than horse roadrolling. Since 1870 the practice of steam road-rolling has been rapidly extending in town and country.

STEEL MANUFACTURE [E. C., vol. vii. col. 819]. The chief researches of smelters and metallurgists within the last few years, in regard to the production of steel, have been directed towards the discovery of some mode of making steel direct from pig iron, without the intervention of other processes, or at any rate with a lessening of the number of processes hitherto followed. The most successful of these new plans is the one due to Mr. Bessemer [BESSEMER STEEL, E. C. S., col. 281], whose steel is found to be advantageous for heavy railway work. Unfortunately the hæmatite, from which ore it ought to be smelted, is small in quantity in England, and is rapidly rising in price. Sweden has a rich supply, but the mines are a hundred miles from the coast; the freight will therefore be costly until the country is better supplied with railways than at present. Spain is also rich in hæmatite, which is now regu

is at present attracting much attention. It appears from a paper by Dr. C. W. Siemens, read before the Iron and Steel Institute in 1873, that the first invention, called the SiemensMartin scrap process, was followed by a second, the Siemens ore process; and that in 1868 experiments were commenced for the development of a new system for the manufacture of steel as well as iron directly from the ore. A smelting-work was established near Swansea; a rotatory furnace was constructed for reducing the iron ore; and connected with this was an openhearth steel-melting furnace. Under this arrangement the reduced iron was converted into steel by its fusion in a bath of cast iron; but later developments enable the smelters to effect the whole operation in the rotating furnace itself. This rotator is 8 feet long by 7 feet diameter; it is mounted on anti-friction rollers, and is provided with gearing to give it any desired degree of rotative velocity; it is closed by a swinging door at one end, and is constructed partly of cast and partly of wrought iron. In order to enable it to bear the intense heat to which it is necessarily exposed in steel-making, the rotator is

lined with bricks made of calcined bauxite, a very refractory mineral. Powdered ore is mixed with powdered coal and suitable fluxes; a high temperature causes the coal to deoxidize the ore; and the liberated metal is changed in the rotator into a kind of puddled iron, which becomes puddled steel by a modification of the process. The peculiarity of the method, as compared with many that have preceded it, consists in the fact that the metal is very little contaminated by the impurities contained in the coal; the revolver is heated by flame, which enters through a passage constituting one half of the axis, and escapes through a passage constituting the other half; the flame is projected with sufficient force to enable it to sweep round the furnace before its escape, and thus the fuel itself does not come in contact with the ore or the metal obtained from it. The point at which the inventors are aiming is to produce steel nearly as good as crucible steel at a much lower price.

Improvements have recently been made by condensing steel when in a semi-fluid state. In 1872 Chevalier Stummer, at the Neuberg Steel Works, Styria, introduced a mode of bringing a pressure of 61b. to 9lb. per square inch to bear upon the semimolten steel, producing a closer aggregation of the metallic particles.

The greatest steel works in existence are at Essen in Prussia, the property of MM. Krupp. No others cover so large an area, employ so many men, or are supplied with such numerous and powerful engines and machines. [KRUPP, FRIEDRICH, E. C. S., Biog. Div., col. 753.] In 1862 there was an estimate that 52,000 tons of cast steel were made annually in Sheffield, besides other kinds. Since that date, the Bessemer process has brought about a great extension of the trade, not only in Sheffield, but by the establishment of steel works at Barrow-in-Furness and other places where none such existed ten years ago; but no official data are obtainable to determine the quantity made.

It is difficult to compare the exports in years widely apart, because the Board of Trade has made changes in the mode of classification, and because the distinction between steel and iron goods is not always clearly stated. The following were the exports for 1872:

practices could be carried on without much danger of discovery, and if discovered there were always plenty of excuses at hand, the truth of which it was no one's business to inquire into, because there was no such thing as a body of persons in authority, who could deal with the matter and punish evil doers. Steeplechasing thus earned a very bad name, and it was not until the Grand National Steeple-Chase Rules were framed and adopted by an influential committee of noblemen and gentlemen connected with the turf, and who now hold the same position with regard to steeple-chasing that the Jockey Club do to flat-racing, that it emerged from the slough into which it had fallen. Since that time it has been a well-conducted and popular sport, although, perhaps, during the winter, when racing on the flat is discontinued, there are too many small steeple-chase meetings held in the neighbourhood of London, their great attraction being the opportunity which they afford for gambling, and not the improvement of the breed of hunters, their frequency and the inferiority of the class of animals entered having a contrary effect.

Cross-country races were first patronised by gentlemen who desired to possess first-class hunters, and who had no objection to give a long price for a good fencer, but when they found that the racing spoiled the jumping powers of their horses, and that all sorts of tricks were resorted to so as to secure success, they abandoned the sport and left it in the hands of horse dealers and others, who made their living out of it. The latter, in order to make it pay, found out that it was desirable to attract the public and collect large fields of horses, and they consequently reduced the size of the jumps to such an extent that they became a mere farce, and cast-offs from racing stables could as easily clear them as the best hunters in the world. Some of the most successful steeple-chasers of the last ten years are animals which have been failures on the flat, and it is extraordinary that horses which have been unable to win mile or halfmile races on the race-course, have yet been able to stay two, three, and four miles across country. For instance, Lord Coventry's Emblem and Emblematic, both by Teddington-Miss Batty, won the Liverpool Steeple-Chase in the years 1863 and 1864, and yet could never distinguish themselves to any extent even over short courses on the flat, although they were bred from a staying strain. The Colonel, winner in 1869 and 1870, one of the best steeple-chase horses of the same period, has the two letters h b, signifying that there is a stain in his pedigree, set against his name, but he did win some fair races on the flat notwithstanding. The Lamb, the winner in 1868 and 1870, also figured on the flat, but with less success than the Colonel, although his opponents were of a very inferior calibre. The two courses of the present day which most represent a fair hunting county are those of Liverpool, where, however, the jumps are not as formidable as they used to be, and Punchestown, in Ireland. At the latter, all the best Irish horses contend, and the event is quite the Derby of Ireland, creating as much interest on that side of the Channel as the great Epsom race does on this. As the courses for the great steeple-chase races of the present day are not of a very formidable character, those animals which combine the speed of the race-horse with average fencing qualities are more successful than the regular hunter, whose superior jumping powers are to a certain extent an obstacle to his success, as he goes up to his fences steadily, whereas the cast-off racer rushes at them at top speed, as if he was competing on the flat, and if he clears them he is soon under way for the next, but if he fails, a serious accident is the inevitable result. Although there is generally a long run in at the finish of an important steeple-chase, and many ex-flat racers contend, yet instances are rare in which the winner was in the rear when he cleared the last fence. A good steeple-chaser should have fair speed, with stamina and endurance sufficient to stay four miles under a heavy weight at a good pace, and to breed this class of animal is most difficult, for if strongly-built mares are put to thoroughbreds, and thoroughbred mares to powerful horses, the result is more often than not a failure. The training of the steeple-chasers is much like that of the flat racers. There are some very celebrated steeple-chase jockeys, and some of the jockeys of flat races are also able to ride across country, but there are, in addition, not a few gentlemen, or amateur riders, who are quite as great adepts as professionals. Hurdle racing is a useless sport, and is hardly to be distinguished from racing on the flat, as the only condition is that the horses should get over or through the hurdles, which in general are of a very flimsy character, and are frequently knocked down by the leading animal. This kind of race acts as a sort of school

for steeple-chasers, and this is the only good word that can be said for it.

STEERING APPARATUS [E. C., vol. vii. col. 825. A few new forms are noticed in HELM, E. C. S. col. 1254; HyDRAULIC STEERING APPARATUS, E. C. S. col. 1303, and RUDDER, E. C. S. col. 1854.] STEREOTYPE. The great advantages resulting from the substitution of paper for plaster of Paris in making the moulds or matrices for stereotype plates, have led to a general adoption of the plan. The method was described twelve years ago in PRINTING [E. C., vol. vi. col. 764]; but it has since been improved in detail, and now conduces much to the success of the rapid processes, especially in newspaper work, noticed under PRINTING, E. C. S. col. 1730.

Stereotyping machines have been devised to expedite the making of the mould or matrix. One such was introduced in 1868. Keys, like those of a pianoforte, are pressed down by the fingers of the compositor, according to the successive letters of the words which he wishes to set up; these pressures liberate types, bring them down in proper order on a surface of some plastic material, and force each of them to make an impress or indentation on it. A series of such indentations form the mould from which a stereotype plate may be taken. The theory is, that the compositor shall be enabled to set up his type and make a stereotype mould at the same time; or, rather, dispense with setting up at all, and produce a mould by one finger-pressure for each letter. But the plan is beset with difficulties, which have not yet been fully surmounted.

STICHOMANCY (σrixos, a line, a verse, and μavreía, divination), a mode of divination by means of verses, much in vogue among the ancients. Slips of paper, on each of which was written a line or verse--commonly from Homer, Hesiod, Virgil, and the so-called Sibylline verses [SIBYL, E. C. vol. vii. col. 549]-were carefully folded, placed in an urn, and shaken together, and the slip first drawn was supposed to afford the desired response. [DIVINATION, E. C. S. col. 774.]

STINGS. Stings of insects, bites of serpents and animals, injuries inflicted by certain fish, punctures received in dissection, and wounds by poisoned arrows, constitute a large proportion of the injuries which have a fatal issue. Some, as the poison of the Cobra di Capello, may cause almost instantaneous death; others, as that of the dead body, death in a few days, and one at least (that of the mad dog) may not begin to act till after an interval of weeks or months. In this place it may be well to indicate the general principles of the treatment which should be adopted in these forms of poisoning. They may be briefly stated as measures to retard or prevent absorption, or dilute the poison, and to neutralise it; to which may be added treatment to be directed to the gaining of time for the poison to eliminate itself by the proper excreting organs.

1. Absorption may be prevented, or greatly retarded, by a ligature tightly applied between the wound and the heart; and in a less degree, and with much less certainty, by swallowing a large quantity of liquid, in order to produce a fulness of the vascular system unfavourable to the work of absorption.

2. The poison may be extracted by the strong and active suction of the mouth, or (if that is at hand) by the cuppingglass.

3. The poison may be certainly diluted, and possibly neutralised, by washing with dilute liquor ammonia, spirits of hartshorn, eau de luce, or a weak solution of chloride of lime; and for common stings of hornets, bees, and wasps, there is no better application than tincture of iodine. Lunar caustic freely used may act favourably by destroying the part to which the poison

adheres.

4. The gaining of time for the work of elimination may be accomplished by the free use of spirituous and ammoniacal stimulants, and, in extreme cases, by the galvanic battery and artificial respiration. As many poisons of the class now under consideration appear to act directly on the heart, a stimulating treatment is that which should, as a broad general rule, be adopted; and among stimulants ammonia in some of its forms appears to take the first place. Where the requisite apparatus is at hand, the injection into the veins of a weak solution of ammonia is to be commended. But in the common run of cases the measures to be recommended and to be immediately resorted to are the ligature, quick washing with hartshorn, strong persevering suction with the mouth, and large draughts of liquids containing small quantities of hartshorn, and a liberal amount of brandy, rum, whiskey, or gin.

STITCH, a spasmodic painful action of the muscles, com

ARTS AND SCI. DIV.SUP.

monly applied to those of the side, brought on by running, riding, &c. When similar contractions occur in the calves of the legs, or in other parts of the body, they are known as cramps. STONE, ARTIFICIAL. In the pottery department of the International Exhibition, 1871, there was an extensive show of this new manufacture. The kinds were mostly under patent, and patentees give their articles different names according to the materials used and the processes to which they are subjected. The older varieties were moulded blocks of plastic materials bound together by Roman cement, Portland cement, &c., which "set" or hardened in the drying. Another class, consisting of varieties of terracotta and of silicates, requires burning. But burnt articles are subject to two practical objections :-(1) burning incurs actual expense and requires time; and (2) articles do not preserve their proper form in the kiln.

Most of the artificial productions now in use are imitations of natural stone, as granite, sandstone, marble, &c., whose particles are bound together without burning. Three examples for illustration will suffice-(1) Ransome's patent stone; (2) Colonel Scott's selenitic bricks and mortar, of which part of the International Building is constructed; and (3) Henry Large's concrete bricks.

Mr. Frederic Ransome, the inventor of Ransome's patent stone, has done much to perfect the manufacture of stone, and adapt it to constructive and other purposes. His projects have been taken up by Ransome's Patent Stone Company, Limited, and are being successfully carried out by them at their works, East Greenwich. It was only in 1870 that the process was matured by which stone is now being made so as to obviate the expense of washing out common salt. In 1861 Mr. Ransome discovered that sand or stone reduced to powder might, by a solution of silicate of soda, be worked into a plastic state, and afterwards moulded in any required form; the moulded body being afterwards immersed in a solution of chloride of calcium. Double decomposition of the two solutions takes place, resulting in the production of an insoluble silicate of lime firmly uniting the sand or powder into a stone, hard, uniform, and durable, provided the chloride of sodium or common salt formed is washed out. This was done, but the washing process is tedious and expensive, and in localities where a sufficient supply of pure water cannot be had it becomes impracticable. Hence the manufacture is limited. It is otherwise with his recent invention. A solution of chloride of calcium not being used in the process, no chloride is set free to unite with the soda, and no common salt formed. Prior to 1870 the discovery was made of a silicious mineral in Surrey, now known by the name of Farnham stone, which has the peculiar property of being soluble in a solution of caustic soda at a low temperature. Taking advantage of this, Mr. Ransome now combines a portion of the Farnham stone with a solution of silicate of soda, or potash, and lime (or substance containing lime), sand, alumina, chalk, or other convenient materials. These are thoroughly incorporated together by reducing them to a plastic form in a mill. Silicate of lime, formed in the process, binds together the materials, and when moulded the stone thus formed becomes in drying compact, increasing in hardness with age, is capable of sustaining a greater pressure than any natural stone used in building, and resists more effectually the influence of water and the atmosphere of towns. Blocks of any size and form required for building purposes can be made, and as they are cemented together by mortar made of the same materials as the blocks are made of, the whole structure becomes one solid body. For example, hollow cylinders 8 feet in diameter and 9 inches thick were thus made in constructing a retaining wall to protect the foreshores of the Thames at Hermitage Wharf, and the result according to present experience is satisfactory. The usual colour is that of newly quarried Portland stone, but it can be made of various colours; its weight is about 120 lbs. per cubic foot. Owing to its uniform hardness and cutting power, it has nearly superseded natural stone for grindstones, scythe-stones, and emery-wheels; its hardness and durability also recommend it for doorsteps, window-sills, stairs, balustrades, &c.

Major Gen. H. Y. D. Scott's stone is a sulpho-silicate compound. His projects only date from 1870, during which year he took out five patents. At first his cement consisted chiefly of lime, clay, and sulphate of lime, or its equivalent of sulphuric acid. He next grinds lime and sulphate of lime, and reduces them to a "slip;" mixes this slip with burnt clay, &c., until the mass becomes sufficiently plastic for moulding into bricks; and from the peculiar properties of sulphate of lime the bricks dry rapidly, 6 L