nails, without cement; “Draining Materials,” “Fire-bricks, Furnace Materials, and Stove Fittings," "Bricks and Materials used in the Construction of Walls," "Accessories to the Decoration of Buildings," and other articles, including pillars and square shafts effectively treated in colour, and with ornamented capitals; and "Raw Materials" illustrated by a section of the Shropshire Coal Field, and specimens, some of which show the relative shrinkages of the clays. It should be recollected that there are other, and perhaps higher, aims in architecture, than demonstrating the serviceableness and scope of any one material; in other words, interests and feelings of manufacturers, and the tastes of architects, are not what should lead to the same conclusions; but the geometrical mosaic is doing excellent service in the decoration of houses; and some of the credit for the obvious future of popular taste will be due to manufacturers and to those whom they have called to their assistance. From the Builder.

CLAY AND METAL PIPE-MAKING.

Clay-ware Pipes, by Zeller, of Ollwiller (Haut-Rhin), enamelled, and Bitumenized Paper pipes, by Jaloureau, of Paris, of good manufacture, for the conveyance of water and gas, were exhibited. The bitumenized pipes are favourably reported on in Paris, as regards durability, after four years' trial; and elasticity is one of their advantages. Tinned lead pipes were shown by Ch. Sebille, of Nantes. An English patent for a somewhat similar description of piping (Bennett's) was sealed in 1861. The French manufacture has been carried on five or six years; and the town of Nantes is served with these pipes. The English method is described as pressing and tinning the interior surface of lead pipe in one operation; and Dr. Letheby, reporting nine days' experiments with common water, rain-water, and distilled water, tried in straight and bent forms of tube, states there to have been complete protection from corrosive action, the most delicate tests failing to discover the presence of lead in the water; whilst common lead, with the same water (rain and distilled) quickly communicated to the water a metallic impregnation. Sebille's piping is, however, tinned on both sides. He exhibited another description of pipe, manufactured from pulverized slate-refuse, or cinders, and about onefifth part coal-pitch. This compound slate-paste, having been heated and well mixed in an iron pan, can be moulded into pipes, bricks, or slabs, and becomes so hard, whilst free from cracks, that neither water heated to 180°, nor any cold, affects it: a 3-inch pipe of usual substance will stand internal pressure of ten atmospheres.

We condense these details from the Builder; in conclusion, the Editor pertinently asks: "Would it not be possible to collect all the specimens of pipes of different materials, for the conveyance of water, and subject them all, or duplicates, to similar experiments, chemical and mechanical; the latter including not only experiments to ascertain the resistance to bursting, but others on the

resistance to collapse, as from a weight of superincumbent earth. The results being tabulated, with prices, a record would be left, the value of which after the Exhibition, in every question of supply of water to town or house would be immense."

Amongst the British exhibitors of Pipes, Mr. J. Chatterton, of Wharf-road, City-road, showed lead, composition, and pure blocktin pipes of the most perfect manufacture; also ordinary lead pipes of all sizes, from 1-32nd of an inch to 6 inches diameter; lead mouldings, polygonal, and multiple pipes, the latter being used for the purpose of conveying various liquids into spirit-vaults, are enclosed in the large pipe for neatness of appearance and facility of fixing on walls, down angles, &c. The three pipes combined are especially designed for domestic purposes, the object being to convey to the different parts of the house hard and soft water and gas. Lead pipes are coated internally with pure tin, for use in those localities where the water forms poisonous salts with the ordinary lead pipe. Lead pipes were shown, lined with gutta-percha, for similar purposes as last named. These were also, by their lightness and remarkable strength, particularly suitable for conveying water in mountainous countries, where they would have to sustain a great pressure; and, from the frost-resisting properties of the gutta-percha, they are invaluable in cold latitudes. The Composition tubes for gas showed a great superiority in material and manufacture, and placed by the side of tin tubes, not only rivalled them in brilliancy, but were found also to equal them in hardness and toughness. The pure block-tin tube specimens were unequalled. Mr. Chatterton also exhibited specimens of Cylindrical Projectiles for smooth-bore guns, intended to obviate the necessity of using a rifle-barrel, with its tendency to fouling; and at the same time to secure that force and accuracy, which under ordinary circumstances are only attainable by the use of the rifle. Instead of receiving a rotatory motion, as heretofore, from a grooved barrel, it derives it from the resistance of the atmosphere acting upon a suitable helical apparatus in the bullet itself. The projectile is in shape a hollow cylinder, open at both ends, and the internal screw is made of different patterns.

NAVAL AND MILITARY MODELS, WEAPONS, AND

APPLIANCES.

NAVAL AND MILITARY MODELS.

In the Court devoted to these articles the visitor could study, almost in a glance, the progress of naval architecture for nearly three centuries past. All kinds of these models were here, from that of the Great Harry down to our last and greatest ship, the Warrior, with lines as fine as a Dover packet. Yet almost a finer model still than the Warrior was shown side by side with what used to be the crack sailing-ship of the Navy as it was in

1840-the old and much-praised Queen. By this now old line-of-battle ship was placed the model of the Northumberland, the newest and most improved of the iron frigates yet building; so that even the least initiated could, at all events, judge of the change which has taken place in shape and size since the introduction of 5-inch ironsides obliged us to build vessels large enough to float with such a casing. This model of the Northumberland is equal, in the minute perfection of its guns, rigging, and fittings, to that of the Warrior, shown by the Thames Iron Company, and higher praise than this it would be difficult to give it.

Close by these was shown a series of most wonderfully perfect Models of Lighthouses, made to scale; which includes all the chief of those great sea-lamps, from the South Stack and Smeaton's chef-d'œuvre on the little Eddystone rock, down to the still more ingenious red-legged tripods which mark sands where no base for a granite structure can be found. Not only were there models of such mechanism as the rough and ready bridges of the Royal Engineers, but models of almost everything which relates to the science of defence and attack, whether of or from land or sea. Models of saps, mines, and covered ways-principally illustrated from works carried out during that greatest of all sieges, Sebastopol-explain how the strongest places must yield to the gradual assaults of military engineering; close by this was another model giving a rough bird's-eye view over London, and showing how it is only necessary to turn the beautifully wooded hills of Surrey and Middlesex into bastions, re-entering angles, dry ditches, caponnières, &c., to make our quiet metropolis as strong a fortress as the lost mistress of the Euxine was before the attack of the Allies.

An important American invention was shown-a series of beautiful little working models of the various machines used in Thompson's patent for Making Boats by Steam, which do all, even to curving and bevelling the edges; so that a rough board passing in at one end of a machine comes out at the other, not only curved, but bevelled and planed. To make a large and strong boat 33 feet long requires at least from eight to ten days' work, and costs for labour alone, exclusive of material, from 127. to 167. By Mr. Thompson's machinery a similar boat can be completed from the rough timber in five hours and a half, and at a cost for labour and machinery of from 17. 158. to 27.

THE ARMSTRONG AND WHITWORTH GUNS.

We now proceed to the Military Weapons. Here was shown the new Gun invented by Sir William Armstrong. It is a rifled breech-loading 70-pounder, but one in which the chamber ventpiece and screw are entirely dispensed with. There is no doubt whatever but that the ventpiece and the movement necessary to place and close it are the least perfect parts of Sir William's invention as applied to very heavy breech-loading ordnance. In this gun it is superseded by a mechanism so simple that it may almost be termed self-acting, and so massive that it cannot be

injured by shot, and, above all, so evenly balanced and sliding on such true surfaces, that a child's strength would suffice to open and close the breech. The gun is built up of wrought-iron coils and rifled in the usual manner; but in the breech on both sides two narrow openings are cut, into which are fitted two wedge-shaped masses of iron with handles. These, when drawn aside, have openings in them corresponding to the bore of the gun, which can then be seen through from end to end, a hollow rifled tube. The shot and powder are then inserted in the ordinary way at the breech, and the foremost of the sliding iron wedges we have mentioned drawn across so as to close the tube. The second and most massive wedge is then drawn into its position so as to jamb both tight, and the gun is ready for firing. By a simple but more ingenious mechanical contrivance connected with the lock of the gun, which slides down a powerful steel bolt that keys the two wedges together, the piece cannot be fired till both wedges are in their place, nor can they be withdrawn until this again is lifted. Only five or six movements of the hand are required to load a 100 or 150 pounder. A gun of this construction has been severely tested, yet not the slightest escape of gas, or rather fire, has ever occurred; and while the breach is almost hermetically closed, a sufficient play is allowed for the wedges to permit of their expansion from the heat of rapid firing. This is, in our opinion, the finest Breech-loading piece of Ordnance that Sir William Armstrong has yet invented. It has all the advantages as to range and strength of material of his previous inventions. It is cheaper because simpler in its method of construction; and can be fired much more rapidly, as it dispenses with the hitherto awkward necessity of lifting in and out the breechpiece, which was, in fact, the only drawback on the use of his very heavy guns for sea service. The gun will, we think, before long supersede the first invention as applied to the heaviest artillery, though the value of what we may now almost call the old method remains as great as ever for light ordnance. The Armstrong trophy attracted a great amount of notice, though really not as much as it deserved, for the whole of that huge Building contained no finer specimens.* It was a tree of Armstrong ordnance, arranged in an exceedingly pretty shape as to outward form, and containing in its structure such specimens of forging and carefully finished workmanship as it is not too much to say had never been seen.

Near the Armstrong Gun were shown sections of Shells of all sizes, both time and percussion. The Time-shell is adjusted by distance that is, the fuse is cut short to burst the charge so many seconds after it leaves the gun, every second representing a space of 400 yards traversed. Thus, after one or two shots for "range, the shell can be burst to a nicety of 50 feet. The Percussion shell, as its name implies, explodes instantaneously on touching any obstacles after it leaves the gun.

*This huge pile of arms was in the nave of the Building.

Sir William Armstrong's segment Percussion-shell is the most destructive missile that the science of modern war has yet brought to perfection. The visitor could judge at a glance of their tremendous power, for close by the shells was exhibited a kind of large iron bee-hive, in which one of the small shells was exploded. There is scarcely a superficial inch of this in which one or more pieces of iron and lead are not sticking.

Near to this were exhibited the Guns of Armstrong's great competitor Mr. Whitworth, whose Gun is still that which has attained the longest range and greatest accuracy, and is still the only piece that has sent as light a shot as 70 lb. through 4 inches of solid iron plate. The Blakeley Gun, also in this Court, is a very good piece of rifled muzzle-loading ordnance, very similar in principle to the "canon rayé" of the French. Even, however, as a rifled muzzle-loader it is inferior to Whitworth's, which has the advantage of being a breech-loader as well. A large Wrought-iron Gun was exhibited from the Mersey works, which, as a perfect triumph of forging, should have been shown side by side with the doublethrow crank of the same firm. The Shells of the Monster Mortar -shells which, when loaded, weigh as much as 25 cwt., are another instance of extravagant invention of which this Court offers as many samples as any other in the Building. Every kind of breech-loading small arm was, of course, to be found here. And here, by comparison, might be seen the superiority of the American invention of Mr. Storm over others. In this piece there is nothing special in either the lock, or stock, or barrel; the only invention, in fact, being the Breech-loading Apparatus, which is applicable to any and every barrel, at a cost, it is stated, as low as some 16s. each. The breech, about an inch, or an inch and a half in length, is fitted to the barrel by an ordinary hinge, which is thrown up or open by a movement of the finger or thumb, the charge inserted, and the breech closed. A breech-loading rifle is the great military desideratum now; so much so that the Prussian army is entirely armed with weapons of this class—very inferior ones, it is true, but infinitely better than any muzzle-loader. Last year some wonderful shooting was made at the Wimbledon meeting with breech-loaders of Mr. Storm's patent adapted to the Enfield and Whitworth rifles. Since then it has been tried by some of the highest professional authorities on musketry, and has been pronounced perfect. Its great advantages may be summed up in the few words-that it requires no special ammunition, is adaptable at the low cost we have mentioned to any rifle, which can then be loaded at either breech or muzzle, it is so simple in its mechanism, that it can be fired easily from 12 to 15 times a-minute, and as rapidly in the dark as in the daylight.—Abridged from the Times.

From the Carriage Factory at Woolwich was shown a series of specimens of Gun-carriages and Ambulances, with which no carriages in the Building could compare for strength, and very few for finish. The utilization of the cask-hoops which lay in tons