connecting-rods, &c.; and hence, 5, a saving of power in transmission, and consequent possibility of transmitting it to a much greater distance; 6, a considerable saving in fixing the foundation of large machines, by making them lighter; 7, enabling the power to be transmitted underground, and beneath the flooring, and not through rooms and workshops, as at present, in consequence of the constant necessity of oiling the spindles and brasses of axle-boxes, and keys of shafting, &c., a result which would conduce to cleanliness and order, and be a great saving of room; 8, and lastly, the power of increasing the speed of the prime mover, without a corresponding increase of power or wear and tear, and thus doing away to a great extent with the necessity of cumbrous pulleys, and other means of multiplying speed. We shall, perhaps, return on another accasion to the discussion of the important result which such a system of oiling would lead to, in reducing the weight and dimensions of shafting and other organs of transmission. Further details upon Busse's system may be found in the Eisenbahnzeitung, 1853, p. 71, and upon De Coster's system in Le Technologiste for October, 1853.

It will not be out of place here to mention, that another form of self-oiling axle-box has been patented in England, by Mr. Paul R. Hodge; he has introduced this apparatus as the best in use in the United States, where no solid fat is employed in the greasing of railway axles. From some experiments made with this new system, under the superintendence of Mr. M'Connell, on the London and North Western Railway, it appears that a tender, employed partially in connection with the express train and partially with a goods train, having been fitted with American axle boxes, and supplied with ten quarts of oil, was worked for four months, during which period its aggregate journeys amounted to 5,743 miles, and on being then examined, sufficient oil remained in the reservoirs to serve for 4,000 miles more, whilst five quarts of dirty oil were obtained from an under reservoir, which could be employed for cutting screws, boring, &c. A comparison between the daily cost of the old system of tallow greasing with Normanville's axle-boxes, and the American system with oil, gave for the former 9 pence, and for the latter 154 pence, being a saving of 7-46 pence per diem for the tender alone. For full details of this system, we refer our readers to the number of the Civil Engineer and Architects' Journal for January, 1853, p. 24.

What is the best mode of Painting Iron Bridges, Gates, and other Iron Work, so as to preserve them from Rust?—The great number of iron bridges now constructed in connection with railways, as well as the general employment of iron in the construction of roofs, gates, &c., renders it a question of great importance to determine what is the best mode of painting them, so as to prevent them from rusting. The usual ground coat applied to such structures is made with red lead but experience has shewn, that rust rapidly forms under the coating, a fact which can perhaps be in part explained by its composition; that substance being a combination of protoxide and peroxide of lead, gradually parts with a portion of its oxygen to the iron, and causes it to slowly rust. Without pretending to decide what is the best substitute for red lead, it may be useful to many of our readers to learn the process adopted with so much success with the Britannia Bridge, especially as we have observed that the use of red lead is still almost universal. The iron work is first well scraped with iron instruments, (a most important point.) then brushed with wire brushes, and finally with stiff hair brushes, until the whole surface is perfectly free from rust. The cracks, joints, and points of contact of bolts, &c., are also cleaned out, and every place where water could lodge filled up with the usual cement, made of a mixture of white lead and red lead. As soon as this cement is dry, the whole is again brushed, when it receives two successive coats of paint, at intervals of from 8 to 14 days between each, according to the state of dryness. The paint employed for this purpose consists of 560lbs. of genuine white lead, 133lbs. of raw linseed oil, 18 to 36lbs. of boiled linseed oil (prepared without litharge), and 18lbs. of oil of turpentine. The more of the boiled linseed oil which is employed, the thinner will be the paint, but the less durable also; only sufficient should therefore be taken to render the paint convenient to work with. The same observations apply to the employment of the oil of turpentine, any excess of which would render the colour less durable and liable to crack. While the fourth coating is still fresh, it is dusted over with well washed fine-grained white sand; a little prussian blue and umber is also added to

Such

the paint used in the last coating, so as to give it a light marine grey tint. a coating is considered to last for five years, after which it is to be completely removed and renewed. The floor and other parts not visible when perfectly cleaned, as before described, receive two or three coats of the following mixture8lbs. of coal tar, 1lb. of spirit of turpentine, and 2lbs. of powdered quick lime; the last coat is also sanded. This painting, which is applied for economy alone, is considered to last for two years, after which it is to be fully cleaned off and renewed. Several railway bridges, both in England and on the Continent, have been painted in this manner with white lead, and we believe with perfect success. Artificial Grindstones.-J. Weld, a manufacturer of Amberg, prepares a peculiar kind of artificial grindstone, with which he has established a considerable trade. These stones are formed of a mixture consisting of 2 parts of bog iron ore, 1 part of sandstone, and part of clay. The bog iron ore is first crushed by stamping, then ground successively in two different mills, much in the same way as china clay is prepared, until it becomes an exceedingly fine powder. The sandstone is crushed between cylinders, and the clay carefully washed and purified; a mixture is then made of these three ingredients in a moist state, in the proportions above given, well worked together, so as to form a homogenous mass, which is then moulded into the desired forms, dried and baked in a kiln.

Another variety of polishing stones of a much finer quality for certain purposes, such as glass-cutting, &c., is prepared by MM. Neppel, of Nevres, whose patent, granted in 1840, is now expired. The basis of these stones is china clay, pipe clay, or other fine plastic clay, the other substances employed being slate, quartz, sandstone, flint, sand, emery, oxide of iron, and iron filings, in proportions varying according to the quality of the stone intended to be produced, from 5 to 20 per cent. All these materials are first carefully selected, and each well purified by levigation and washing. This done, the materials are mixed in the proper proportions, and introduced into a mill, where they are ground with water, an operation which lasts from three to four days, with a mass of from 2 to 3 cwt. When properly ground the mass is passed through a sieve made of copper, the degree of fineness of which depends upon the quality of the stone to be made. The mass is now allowed to slowly dry by natural evaporation, after which it is moistened from time to time, so as to keep it of an uniform plasticity. Previous to employing it, it is well kneaded, then moulded in plaster moulds. rubbed even with sand-paper when taken from the moulds, after which the moulded pieces are allowed to dry very slowly, to prevent them from cracking. When fully dried they are placed in seggars of fireclay, hermetically closed, and exposed to a heat between that employed for firing stone-ware and porcelain.— Deutsche Gewerbezeitung, Heft 7, p. 415, 1852.

Karl Karmarsch describes another kind of grindstone, made by melting shelllack, and adding a proper quantity of emery or fine sand, and pouring the melted mass into moulds. When large rotatory stones are to be made in this way, it is recommended, in order to save the material, to surround an iron drum of nearly the required size, and about an inch in thickness with the mass. In general, however, only small stones are made of this substance, the chief advantage of which appears to be, that it yields by use a very heavy dust, which at once falls, and does not spread about the workshops, to the injury of the health of the workmen, as that produced by sandstones, when used dry, does. This mode of preparing artificial stones has been known for a considerable time, but recently a new and ingenious application of the material has been made by Heinrich Spann of Hamburgh, in the production of his so called mineral files. The usual proportions of sand or emery and shell-lac employed are, parts of the former and 1 of the latter. These proportions must necessarily vary, however, according to the degree of fineness which the files should have. The chief point apparently to be attended to in their manufacture is, that the grains of sand should be of nearly uniform size. These files, which are very cheap, can be used as substitutes for metal files in all cases; they may be used dry or wet, upon wood or upon glass, and in many cases even with oil, indeed, for working with the latter liquid they appear to be better adapted than steel files.-Mitth. des Hannov. Gewerbevereins, 1853, p. 140, through Dingler's Polytechnisches Journal Bd. 130, Heft. 3, Nov. 1853.

On the use of Alloys of the more easily fusible metals for Plumber-Blocks, by Karl Karmarsch.-It is well known that plummer-blocks have been recently made of alloys of easily fusible metals, and employed in all kinds of machines, in consequence of the advantage which their employment presents of using the axle end itself as the core for making the mould, and thus saving the expense of boring out the shaft cushions. When the pressure on the spindle is small, a mixture of 17 parts of lead and 3 parts of antimony answers very well, and is at the same time very cheap. Harder ones, capable of bearing a greater pressure, may be made with lead, tin and antimony, or of tin and antimony without the addition of lead. An alloy of tin, antimony and copper is very well adapted for heavy machinery, or those whose axes have considerable velocity of rotation; such an alloy has even been found serviceable for the plummer-blocks of locomotives. Mr. Karmarsch has communicated the following proportions for the composition of such alloys, with the view of directing attention to so important a subject:1. Alloys of Tin and Antimony.-3 parts, and even up to 5 and 6 parts of tin, have been prescribed for each part of antimony. The antimony is to be first fused with its own weight of tin, and the mixture then poured into the remainder of the tin, melted in a different pot, and the whole well stirred. In this way a more perfect and homogenous mixture of the two metals is obtained, than when the whole of the tin is at once fused with the antimony.

2. Alloys of Tin, Antimony, and Copper.-The following table contains the composition of all the alloys which he has been able to procure, arranged according to the proportions of copper, being also the order of their hardness:

A specimen of an alloy used for plummer-blocks by Maudelay, Sons, & Field, Westminster Road, Lambeth, London, analysed by Dr. Heeren, of Hannover, gave the following results: 71-10 of tin, 6-85 of antimony, and 22:05 of copper, which would correspond almost exactly with the simple proportions of 1 of antimony, 3 of copper, and 10 of tin. This alloy is distinguished from all the preceding ones in this, that the quantity of copper is not only greater than in either of the others, but exceeds that of the antimony. This large proportion of copper, although it increases the cost, contributes very materially to the hardness and toughness of the alloy.

The alloys of tin, antimony, and copper, are best prepared by melting the copper first, and then adding the antimony, together with about or of the tin, and having carefully stirred the mixture, adding the remainder of the tin. In making the alloy marked ƒ above mentioned, the quantity of tin being too small to divide, might be added at once.-Mittheilungen des Gewerbevereins für das Königreich Hannover, 1853, p. 149, 150, through Polytechnisches Centralblatt, No. 20, October, 1853.

To render Sandstone and other Porous Materials impervious to Water.-The sandstone is first heated to a temperature of about 400° Fahr., and then plunged into coal tar, heated to about the same temperature, and allowed to remain in it for about eight hours. In this way a mass is obtained so solid, that it is scarcely possible to break it with a hammer. Bricks and tiles require only four hours steeping, at

a temperature of about 230° Fahr. (Acid cisterns and refrigerators of Yorkshire sandstone, and many other applications of that material, have been boiled in this way, in tar, since several years, in many of the chemical factories of Great Britain, and with the best results).—Förster's Bauzeitung, 1853, p. 35.

New Species of Printing of importance to the Lace and Sewed Muslin Trade.Under the name of nature's own printing, Mr. Von Auer, of Vienna, has announced a peculiar method for obtaining impressions of the leaves of plants, &c. The process consists simply in taking two polished metal plates, one hard, the best substance being copper, and the other soft, as for example, a plate of lead, and laying the article to be copied between them, and passing the plates between the rollers of a press, such as lithographers use. By the great pressure excited, a beautifully sharp and faithful copy of the article is produced on the leaden plate, from which impressions can be obtained, or by electrotypeing it, a still better plate may be obtained, which can be employed for printing thousands of copies. The dried leaves of plants can be copied in this way, and by using gutta percha gently heated, even moist plants will give impressions. The chief use of this new art will, however, be, to the reproduction of lace, &c., for if a piece of lace, or of worked muslin, be placed between the plates instead of leaves, a beautiful intaglio copy will be produced, from which printed patterns can be provided. Such plates might be at once employed to print designs upon the muslin sent out to be worked. It is but just to remark, that a similar invention was made about twenty years ago by a Dane of Copenhagen, of the name of Peter Kyhl, who, having died before he perfected the art, the idea was lost sight of.

Chemical Researches on Dyeing, by M. Chevreul.-M. Chevreul has presented his ninth memoir to the Academy of Sciences, containing some of the curious and important results of the investigations which he has been carrying on for several years in his capacity of Director of Dyeing at the Gobelins, upon the physical and chemical laws which act in the dyeing of animal and vegetable tissues. The public are already familiar with his beautiful observations upon the harmony and simultaneous contrast of colours, subjects upon which we shall have many opportunities of speaking. The results in his late memoir are not less important, and although apparently of an exceedingly theoretical character, they are of the highest practical utility. It is much to be regretted that our dyers should remain ignorant of the scientific principles of their art, and yet there is perhaps no branch of trade which could derive so much immediate benefit from the progress of physical and chemical science. Any person who paid attention to the specimens of dyed and printed fabrics lately exhibited in Dublin, will at once admit how deplorably this ignorance was exhibited by most, if not all, of our manufacturers in these departments, and in none more so perhaps than in the poplins. The same observations apply in an equal degree to another and different branch of manufacture, stained glass.

M. Chevreul employs the term capillary affinity to designate the force which acts in fixing the colouring matter to the tissue with which they combine. The decolourizing action of charcoal upon liquids comes in part under this category, and indeed the first ideas of M. Chevreul were derived from some experiments which he made so early as 1809, upon the action of that substance upon certain bodies. Capillary affinity affords so striking a contrast to the ordinary phenomena of chemical affinity, that one is naturally led to look upon this kind of force as quite distinct. Thus, for example, gravel, coarse sand, and artificial cements, perfectly freed from their soluble constituents, when placed in contact with lime water, are capable, by prolonged contact, of abstracting a certain portion of the lime from the water. The quantity of lime thus removed by the gravel and coarse sand of the River Seine, from lime water containing 137 of lime in 1000 parts of water was 0.17 after a contact of about 80 days, and 0.71 after 13 years. The separation of lime from water in this way by substances which have no apparent tendency to unite chemically with it, exhibits in a very striking manner the peculiar character of this variety of force.

These results naturally lead to the question of-In what manner does wool, silk, and cotton act, at the ordinary temperature, upon the aqueous solutions of chloride of sodium, chloride of mercury, sulphuric and hydrochloric acids, lime water,

solution of hydrate of barytes, nitrate of lead, and yellow prussiate of potash? The experiments made to solve the question led to results which may be classed under three categories, and which indeed might be deduced a priori-1st. The solution experienced no change in the relative proportions of its immediate principles. Thus cotton plunged into a solution of chloride of mercury absorbs the salt and the water in the same relative proportion in which they existed in the solution; and yet it retains a portion with such force, that when washed with water until no reaction was produced with nitrate of silver, its behaviour with colouring matters was quite different from that of pure cotton. 2nd. The solution ceded more water to the solid immersed in it, than it did of the salt dissolved in it. Cotton plunged into a solution of alum, absorbs a greater relative proportion of water than of alum; still after a number of repeated washings it retains sufficient alum to be weakly dyed in solutions of cochineal or of log-wood. 3rd. The solution ceded more of the substance dissolved in it than of water, to the solid immersed in it. Cotton placed in contact with lime or baryta water comes under this head; so do wool and silk, with reference to chloride of mercury. In all such experiments, regard must be had to the temperature of the solutions, the quantity of liquid employed, and the duration of the immersion; conditions which, it is needless to observe, would cause the result to vary. M. Chevreul is also of opinion, that in all the preceding cases cited, the whole of the absorbed soluble substances might be removed from the tissues by repeated washings.

The influence exercised by solid bodies upon certain solutions, shows that filters may exercise a particular chemical action upon the liquids which pass through them, a fact of considerable importance to the practical chemist and pharmaceutist. The great quantity of water employed in dyeing in the vat requires, relatively, a much larger proportion of salts (mordants) than what fixes itself upon the goods. Thus, in the dyeing of wool, either as yarn or as woven fabrics, 16 parts of alum are employed in the dye beck, for every 100 parts of wool, although only 1.26 parts combine with the tissue, but in the present condition of dyeing this quantity is necessary, for if the affinity of the water for the alum was not satisfied, the tissue could not overcome that affinity, so as to combine with a sufficient quantity of the alum to produce a good dye. It is in this way that dyeing by the padding machine, as is now so frequently practised for Turkey reds, is so much cheaper. than vat-dyeing. Nevertheless M. Chevreul was led from many trials to the conclusion, that dyeing in the vat may be done much more economically than we do at present.

M. Chevreul is of opinion that his experiments will materially assist in solving many physiological problems; because the moment it is proved that an organic tissue can react upon a solution, so as to appropriate one of its proximate principles, in a greater proportion than it does another, we can easily understand that analogous results would take place in the animal economy. Transudation of water may take place through a membrane, a cell, or a vessel, to the exclusion of the substance held in solution, and that, even where no glandulous apparatus exists. They also show how solutions which act upon the organs of taste, or even in the interior of an organ, may produce results at a certain degree of concentration, which disappear, however, or are not at all produced, when the relative proportion of water is more considerable.

These experiments also explain in a satisfactory manner why the roots of plants plunged into certain saline solutions, absorb proportionally more water than they do of the salts dissolved. And finally, it may be that dry tissues can concentrate aqueous solutions to such a degree as to make the salt crystallize by absorbing the water. Thus if a solution of chloride of sodium be introduced into one limb of an U-shaped tube, and some dry tissue, as for example, some tendons, into the other, it will be found after a couple of days, the tube being hermetically sealed, that a crystalization of the salt will take place above the level of the liquid.— Comptes Rendus de l'Academie des Sciences, No. 23. June, 1853.

On the Substances best adapted to prevent the Putrefaction of Animal Matter, and to absorb Ammonia, &c., by M. Payen.-M. Payen has presented to the French Academy, the results of a number of experiments on the absorption of ammonia, and on the action of certain substances in preventing the putrefaction of animal matter. These experiments are of considerable interest in counexion both with