It is with the oxide of gold that M. Briant proposes to form his bath; he takes of and having dissolved them, the oxide of gold with its filter is added, and the whole boiled during 20 minutes. The oxide of gold dissolves, and there is formed at the same time a precipitate of sesqui-oxide of iron. It is allowed to cool, and is then filtered, by which a yellow liquid fit for use is obtained. The objects to be gilt should be well cleaned, and attached to the zinc pole of an element of Daniell, while the upper pole is connected with a platinum plate. The gilding may be effected in a warm or cold solution; in the first case, the deposit forms more rapidly, but with less delicacy. In order to obtain a durable deposit, and analogous to fire gilding, several hours are required. When the liquid is exhausted, oxide of gold is again added, by which a fresh precipitation of oxide of iron is produced. The gilding thus obtained perfectly admits of being burnished, and of undergoing all the operations employed to produce mat or dead gold. M. Jacoby makes the following remarks:-One of the most difficult problems to solve in this branch of manufacture is the production of dead surfaces. Although we know the nature and manipulation of the process, it is only the Parisian workman who can perfectly succeed in this field; hence it is that these operations are always conducted by French workmen, as well in native establishments as in foreign establishments of some importance. The production of dead gold is always accompanied by loss of metal, inasmuch as it necessitates a system of corrosion by chlorine. Nevertheless, Briant's process enables a matted surface to be obtained by galvanic agency, which is not inferior to the best of Paris, whilst it does not require any of those subsequent operations of the kind required by fire gilding. This deadening is spontaneously produced as soon as the coating of gold has acquired a certain thickness; it is more beautiful when the operation is carried on in the cold; by a very simple artifice a more or less reddish tint, on the one hand, or a whitish one, on the other, is produced: it is merely sufficient to dilute the bath by a greater or lesser quantity of water. When the objects to be gilded are polished and brilliant, the electro-gilding will also be brilliant, and it requires a longer time and a thicker coating of gold to obtain a deadened surface. It is therefore important to communicate, in the first instance, to the objects a deadened surface by the process employed in fire gilding, or more economically, by covering them at once with a thin pellicle of copper by electric agency, which, as is well known, can be obtained with a beautiful matted service. But in both cases it is indispensable to eliminate the last traces of acid which might adhere to the objects; for this purpose they should be washed with water rendered alkaline and then with pure water. An important point to be considered is the choice of the substance which is to be employed for protecting the points which should not be gilded, for it must be remembered that the gilding bath is alkaline; for this purpose plaster impregnated with an alcoholic solution of lac is recommended. M. Jacoby mentions another process for obtaining a good electro-gilding: he dissolves a ducat of rolled gold in nitro-muriatic acid, evaporates to dryness the solution, and dissolves the product in a liquid containing 576 grains of yellow prussiate of potash and 144 grains of caustic potash; the mixture is then boiled during a half-hour, after which it is filtered and diluted with a sufficient quantity of water to give to the bath the weight of 340 grammes. After this the bath will be found composed in the following manner :— Gold 1 part. 12 120 -Oesterreich. Gewerbeblatt, through Bulletin de la Société d'Encouragement, No. 16, August, 1854, p. 506. MANUFACTURES FROM MINERAL SUBSTANCES. Action of Sea Water upon Cement.-In No. IX., p. 269, of this Journal, we gave an account of the observations of MM. Malaguti and Durocher, upon the action of sea water upon hydraulic cements. According to these chemists, cements which contain peroxide of iron always resist the distructive action of sea water better than those containing but little; indeed they seem to consider the indestructibility to be in a direct ratio to the amount of iron. M. Vicat, who has done so much on this subject, has, however, communicated to the Academy of Sciences a number of well established cases in direct opposition to this view. Cements indestructible in Sea Water. Medina Cement, employed at Cherbourg Caher's cement tested in the laboratory during 7 to 8 years These two cements have actually the same value for sea water. Cements slightly attacked. Pouilly Cement Vassy cement, baked, average Portland Cement These three cements crack on the edges after some months of immersion. 16:30 Puzzolana, from Rome, standing well in sea water, with fat lime 12.00 ... 35.00 All the puzzolanas of the Volcanoes of the Vivarais, very bad, average, 20·00 Artificial Puzzolanas. All the artificial puzzolanas made with white clays, and properly applied, resist the action of sea water. There are some which contain no iron. Those containing most yield from 1.20 to 2·00. Hydraulic Limes. The famous limes of Ardèche, known under the name of Theil limes, the only ones which, up to the present, can be authentically shown to yield, with sand alone, mortars which are not destroyed by the action of sea water, contain only insignificant quantities of peroxide of iron, and sometimes contain none at all. Excellent limes suited for fresh water, and which contain as much as 9 per cent. of peroxide of iron, have yielded mortars with sand which perish in sea water in a few years. These facts, M. Vicat seems to think, are sufficient to show that the importance attributed to peroxide of iron by MM. Malaguti and Durocher are not borne out generally, however well it may accord with a few exceptional cases. The best hydraulic compositions are, without exception, attackable by sea water when they are immersed in it fresh; to appreciate their value properly, it is necessary that they should have acquired cohesion, more or less advanced, under certain conditions.-Comptes Rendus de l'Academie, 28th of August, 1854. MACHINERY, MANUFACTURING TOOLS, AND INSTRUMENTS IN GENERAL. Machinery for making Spikes.-John Wootton, of Boonton, New Jersey, has obtained a patent for an improvement in machinery employed in making nails and spikes. Cut nails are clipped or cut out from metal plates by reciprocating knives, and are not made tapering. They have usually been made with one set of die rolls, and have not been very perfect, the sides being more or less feathered. By the improved machinery square nails or spikes are tapered on all sides, and drawn to a point; this is effected by two sets of die rolls, the one set forms the spike with its taper, and the other set takes it from the first and finishes it smooth and tapering.-Scientific American, September 16th, 1854. Tempering and flattening Saws.-An improvement in the mode of tempering and flattening saws has been patented by William Clemson, of Boston, United States. It consists of two iron plates placed horizontally one above the other, these plates being heated over a suitable fireplace. The tempering and flattening of the saw are effected simultaneously by drawing the saw between the heated plates. As the saw passes between, it absorbs sufficient heat from the plates to effect the necessary tempering, while the flattening is done by the pressure of the upper plate. When a saw has been previously hardened it requires to receive a certain degree of heat before passing through the plates; if not sufficiently heated it will break during the process. On the other hand, if too hot it will spring back to its original unevenness after having been drawn through. To prevent this the edges of the plates, where the saw enters, are levelled in such a manner that before the saw arrives between them, every part of it becomes heated by radiation.-Scientific American, September 9th. Sawing Machinery.—Charles F. Packard, of Greenwich, Connecticut, has patented an improvement in sawing machines for sawing laths, pickets, &c., direct from the log. It consists in the use of a vertical circular or reciprocating saw, and a series of horizontal circular saws, the latter being placed upon one shaft at a suitable distance apart, said shaft being attached to a vibrating bed operated in such a manner that the horizontal saws will be thrown outward from the carriage and log when these are moved in one direction, and then thrown towards the carriage and log when they are moved in the opposite direction. When the horizontal saws are thrown in towards the log, they cut into it the exact distance of the width of the pickets, laths, or whatever stuff they may be cutting, but do not separate them from the log; after they are thrown out when the log carriage has travelled to the end of the way, the vertical cutting saw is thrown into gear or action, and it cuts out the series of pickets or laths from the logs. Condenser for Wool Carding Machines.-William H. Howard, of the City of Philadelphia has obtained a patent for improvements in woollen condensers. The invention consists in a means of keeping several slivers separate, and effectually preventing long staples becoming entangled when being conducted from the doffer to the condensing apparatus. The spools on which the slivers are wound are so placed in guides that the full spools can be removed and the empty ones substituted without waste of material, or interruption of the work. The doffer roller is divided into sections by spaces, and the lower roll is divided into corresponding sections by discs, so that the long staple of several slivers, is conducted forward without ever becoming entangled.-Scientific American, September 2. Sewing Machines.-About five years ago we do not believe there were more than three or four sewing machines in use in the United States, now they can be counted by thousands. They are found in the factories and in the private dwellings, sewing the coarse bag and the most delicate piece of cambric. These machines since they were first introduced have advanced towards perfection with a rapidity that is truly astonishing. So many patents have already been obtained for improvements, that it is very difficult to keep pace with their progress; this is evidence of their importance, and at the same time, it is a sign that applications of them for various purposes, demand new modifications, devices, and arrangements. A patent has been obtained by Charles Parham, of Philadelphia, for a sewing machine combining two threads, a shuttle and needle, the object of which is to dispense with the shuttle race, in order to obviate the friction attendant on its use, and which, requiring oil to lubricate it, often soils delicate articles. He employs a shuttle carrier in which the shuttle fits so as to allow it to pass through the loop, but requires no movement independent of the one which is given to the carrier, and which requires no fixed guide to produce friction, excepting on the side which does not come in contact with the threads. Perry's Breech-loading Rifle.-The peculiarity of the breech-loading fire arm consists in the combination of a vibratory charge holder working on an arbor in a socket, and moving in a circle; a magazine or tube in the breach for fifty percussion caps, a piercing cone in connexion with the exploding nipple, which introduces the fire to the centre of the cartridge, producing instant explosion; also a tube forming an adjustable gas joint with the barrel, and so arranged as to be self-cleaning in the joint, which prevents any obstruction by rapid firing; all combined so as to introduce each charge separately and without breaking the cartridge, a single cap being at the same time placed upon the nipple. The charge-chamber is a little larger than the bore of the barrel, so as to prevent windage, and give the same advantage as the Minie ball does to muzzle loaders. It can also be charged with powder and patch, and no cartridge used if desired, as the breach-chamber is loaded like a common shot gun. This rifle is said to possess one-third greater penetrating power with one-sixth less powder than any muzzle-loading one. A ball fired from this rifle has penetrated through a target composed of 18 pine boards, each one inch thick, and an inch apart, at a distance of 80 yards. It was originally patented in 1849, but a second one is now to be taken out for improvements.-Scientific American, September 16th. Comparison of Iron and Wooden Vessels.-In a note attached to his translation of Fincham's Outline of Ship-building, M. Nillus, of Havre, makes some interesting remarks on the comparative advantages of wooden and iron vessels, which we here present in an abridged form. Almost all vessels, whether in wood or iron, have hitherto been constructed on a wrong principle. The greatest possible strength has been given to the sides and bottom, while the deck has been neglected. But a ship should be regarded as a great tube or box, capable of sustaining a load at its middle while suspended at its ends, or conversely of sustaining loads at each end while supported at the middle. To obtain this result with the least weight of materials the upper and lower parts of the vessel, otherwise the deck and the bottom, should be the strongest Înstead of this the deck is usually slight and weak, and is generally regarded only as a platform to be used for working the ship, or as a covering to keep the water from the interior of the hull. Iron ships should form a tube, closed at each end, and strengthed by ribs and cross-beams forming continuous pieces, so that the tube might be considered as strengthened by a series of rings. The sides should, of course, be rivetted to the ribs, so that the whole would form something analogous to a tubular bridge. Even the present construction of iron steamers is much superior in solidity to that of wooden ships, as a few examples will suffice to show. The Great Britain remained during the entire length of a severe winter fixed on the rocks at Dundrum, and when released from her critical position was capable of being so repaired as to become a packet-ship to Australia. A recent example is furnished by the Ward Queen, constructed by Scott Russel, with a length twelve times as great as her maximum breadth, a very high proportion for a sea-going vessel. This small steamer was employed between New IIaven and Dieppe at the period of the accident. In entering the port of New Haven, at low water, with the channel too shallow, she grounded heavily and was suspended by the middle. A breaker took her broadside on and cast her on the beach, where the passengers easily and safely disembarked. Notwithstanding the force with which she was cast ashore she was again launched without any strain, and was able to proceed to London for examination. After a careful inspection no important injury could be discovered. A wooden vessel of the same dimensions, under similar circumstances, would doubtless go to pieces, or at least be seriously damaged. To show that the annual cost of wear and tear is less with iron than with wooden vessels, M. Nillus refers to two steamers, each of ninety horse power, on the packet service between Dover and Calais. One of these, the Midgeon, is of wood, and cost £10,121. The other, the Dover, is of iron, and cost £10,153. The annual repairs of the Midgeon cost £668, while those of the Dover cost only £293. The wooden vessel thus requires 66 per cent. of her first cost for annual wear and tear, while only 2.87 per cent. of the first cost is required for the iron vessel. This extraordinary proportion in the relative cost of wear and tear in these two vessels might be, in part, attributed to the Midgeon being two years older than the Dover, but this would be far from completely explaining it. Hitherto iron vessels have entirely failed for the purposes of war. Numerous experiments made in France and England have clearly demonstrated their inapplicability. A ball fired at an iron hull strikes the side, and continuing its course right through, will come out at the other side; sometimes it breaks into dangerous splinters which kill and wound in all directions. Moreover it is impossible to perfectly close up the hole left by a cannon ball in the iron plate from the jagged edge turned to the interior of the ship. M. Nillus concludes that iron is much preferable to wood as the material for merchant and passenger vessels, but is entirely unsuited for the construction of ships of war. ART. V.-Bulletin of Industrial Statistics. STATISTICAL FACTS FROM THE FOURTEENTH REPORT OF THE FLAX IMPROVEMENT SOCIETY OF IRELAND. Effects of the War upon the Imports of Flax.-As 60,000 tons out of 80,000 tons, constituting the average annual import of flax into these countries, and fully two-thirds to three-fourths of the flax seed employed in Ireland come from Russia, it was reasonably anticipated that a war with that country would seriously affect our supplies of flax and seed. Owing, however, to the neutrality of Prussia, and the permission to import Russian produce through her ports, no disturbance has taken place in the supply for this year, which has been on the contrary rather larger than usual. The total import from all parts for the year ended the 5th of October, 1854, was 86,837 tons of flax against 74,418 in the same period of 185253: no reliance, however, can be placed on the future. The Irish Flax Crop of 1854.-The entire area of land under flax this year has been 150,972 acres against 174,589 acres in 1853, or a diminution of 23,607 acres, or about 14 per cent. The falling off is not so great as had been anticipated, owing to the exertions of the society in the spring. The average annual growth from 1847 to 1853 inclusive, was 103,939 acres, so that the crop of 1854 is about 50 per cent. above the average of the previous seven years. If 1853 be left out, the annual average of the preceding six years is reduced to 89,677 acres, and this year's crop is nearly 67 per cent. greater than that average. In 1853 the yield of flax was very much under an average, and did not yield the usual profit to the farmer; but it is believed, that notwithstanding the diminution in the area of land under flax, that the quantity of marketable fibre this year will be equal to that of last year's crop, and its value may be roughly estimated at about two millions sterling. The quality is generally of the lower kinds; the fibre is strong, and yields well in the spinning mills. The Society's Practical Instruction.-The usual grant of £1,000 from the Irish Reproductive Fund having been granted this year to defray the expenses of practical instruction in certain counties of the South and West, this branch of the Society's operations was on the same scale as formerly. Nineteen instructors were employed at the usual seasons in imparting practical information to flax growers. They were located in districts of the following counties:-Donegal, Londonderry, Down, Cavan, Leitrim, Sligo, Mayo, Galway, Roscommon, Longford, Westmeath, Meath, Louth, Wexford, Cork, Kerry, Clare, Limerick, and Tipperary. Markets in the new Flax districts of the South and West.-The first attempt to establish a round of markets in the new flax districts having been successful, especially in inspiring confidence among growers, the committee again arranged for holding flax markets in last March in Cork, Limerick, Athlone, and Enniscorthy, where about 50 tons of fibre were disposed of. In order to increase the stimulant afforded by these local markets, the committee gave £20 in prizes for the best quality, and for the largest quantity of flax sold in each. The highest price obtained was £84 per ton, and the largest quantity sold by an individual was 12 tons. Saving of Seed.-The importance of saving the seed of the flax crop is now, thanks to the exertions of the Flax Society, beginning to be fully appreciated. |