pressure. He trusted that this highly reprehensible practice had been wholly abandoned. 2d. That by hydraulic pressure obtained by a force-pump, which does not afford an absolutely reliable proof that the boiler has passed the ordeal without injury, and moreover requires a special apparatus. The plan which had been adopted by the author for two years past, with perfect success, was free from the objections which applied to the above, and is as follows:-The boiler is entirely filled with water; then a brisk fire is made in or under it. When the water has thereby been warmed a little, say to 70° or 90° Fahrenheit, the safety valve is loaded to the pressure up to which the boiler is to be tested. Bourdon's or other pressure indicator is then constantly observed, and if the pressure occasioned by the expansion of the water increases continuously up to the testing pressure, without sudden, stoppage or diminution, it may be safely inferred that the boiler has stood it without strain or incipient rupture. In the trials made by the author, the pressure rose from zero to 62 lbs. on the square inch in five minutes. The facility of proving a boiler by this method was so great, that he trusted that owners would be induced to make those periodical tests, without which, fatal experience has shown, no boiler should be trusted.

Congress has authorized an addition to the Louisville and Portland Canal, by the following resolution :

A RESOLUTION AUTHORIZING THE ENLARGEMENT OF, AND CONSTRUCTION OF A BRANCH TO, THE LOUISVILLE AND PORTLAND CANAL.

Resolved, by the Senate and House of Representatives of the United States of America in Congress assembled, That the president and directors of the Louisville and Portland Canal Company be, and they are hereby authorized, with the revenues and credits of the company, to enlarge the said canal, and to construct a branch canal from a suitable point on the south side of the present canal, to a point in the Ohio River, opposite Sand Island, sufficient to pass the largest class of steam vessels navigating the Ohio River: Provided, That nothing herein contained shall authorize the said president and directors, directly or indirectly, to use or pledge the faith or credit of the United States for the said enlargement or construction. It hereby being expressly declared, that the Government of the

United States shall not be in any manner liable for said enlargement and construction. Provided, further, That when said canal is enlarged and its branch canal constructed, and its cost of said improvement paid for, no more tolls shall be collected than an amount sufficient to keep the canal in repair, and pay for all necessary superintendence and management.

Approved 24th May, 1860.

NEW YORK CITY RAILROADS.

The business of the New York City roads for the year ending Sept. 30, 1859, were, according to the State Engineer's report, as follows:

The increase of passengers on the Third Avenue is the largest, being over 20 per cent; that of the Eighth is 11 per cent; Sixth, 16 per cent; Second, 15 per cent; and Harlem, 14 per cent. The average is 15 per cent. At this rate of increase there will be, in a year or two, required double the quantity of street railway accommodation to do the passenger business between the two ends of the island.

RAILWAYS OF CONNECTICUT.

GENERAL STATEMENT OF THE LENGTH, COST, AND OPERATION FOR THE YEAR 1859, of THE RAILWAYS OF CONNECTICUT.

Totals and averages

..........

594 27,461,247 9,512,452 8,668,545 1,410,116

The eight miles of the Boston and New York Central Railway in Connecticut are not included in the above length.

According to the report of the preceding year.

The New London, Willimantic, and Palmer Railway went into the hands of the trustees of the first mortgage bond holders in January, 1859.

The revenue given is $141,641, the expenses $66,708; but the net, $52,813; how such a difference is made we do not see: the arithmetical difference being $74,938.

N

JOURNAL OF MINING, MANUFACTURES, AND ART.

TIN-ITS USES AND COMMERCE.

There are thousands of persons who have no further knowledge of tin than that of beholding it in the form of common pails and pans. Well, to use an expressive Irishism, "such tin is no tin at all." It is simply thin plates of iron coated with tin metal, the proper name of which ought to be tinned sheet-iron. Tin is one of our most useful metals, because it is employed for a great number of purposes. We propose to give some information respecting it, which will be new to most of our people, and interesting, we think, to all.

Tin is one of the most ancient metals—that is, it was well known to the ancients; and it is very well established as a fact that the Phoenicians, those olden masters of the sea when Tyre was in her glory, made voyages to Cornwall, and obtained tin from the mines in that district, long before Britannia was known to the Romans. It was this tin, alloyed with copper, which formed the old bronze armor of the Asiatic warriors; and it may have been furnished also by the renowned Hiram, King of Tyre, the great architect and friend of Solomon, for the building of the first and unapproached Jewish temple. In appearance, this metal resembles silver when first polished; but it sooner becomes dim, because a thin coat of oxyd forms early on its surface when exposed to a moist atmosphere. It is quite ductile, and may be rolled out into very thin sheets, called tin-foil. When undergoing this rolling operation, it is kept at a temperature of about 212° Fab., at which heat its malleability is greatly increased. A common method of making tin-foil is to form ingots of lead and tin-the former in the heart of the ingot, the latter on the outside--and to roll these out into foil. By this process, the tin is retained on the outside, however thin the ingots may be rolled out, while the poisonous lead is kept inside; and by this means the cost of the material is not one-half what it otherwise would be if made entirely of pure tin. A patent has been secured for this invention, and by the reduction caused by it in the price of foil, the latter is now employed for a hundred purposes, such as wrappers for tobacco, labels on bottles, etc., for which paper and other substances were formerly used.

Tin is also extensively employed in the chemical arts, such as by calico-printers and dyers, for making what are called "spirit mordante" and "stannate salts." It is this metal which gives its brilliant hues to the rich crimson shawl and the azure-blue robe of the fashionable lady; and it forms the basis of many other colors on silk. cotton, and woolen fabrics. For this purpose, the metal is commonly dissolved in an acid, such as hydro-chloric or nitro-muriatic, which, in a diluted state, forms the chemists' "spirits." Instead of dissolving it as an acid for such purpose, as was exclusively done in former years, it is now combined with an alkali, and forms the stannate of soda, a salt resembling pearlash. In this form it is now extensively employed in Europe, and the writer of this has had some of it in his possession for more than a year, but has endeavored in vain to make some of our practical chemists appreciate its advantages. Tin

dissolves in some acids like white sugar in hot water; but the action which takes place in the former case is chemical--in the latter, merely mechanical.

The tinned-plates employed by our "whitesmiths " for making milk-pans, pails, and such like articles, are all imported from England, to which country their manufacture is confined. We also import great quantities of this metal in pigs, called "block-tin." It is principally used for making bronze alloys for machinery and "white metal," formerly called "Britannia metal," which is an alloy composed of tin, copper, and antimony. Very small portions of the latter two metals are used in the alloy--only a sufficient quantity to render the tin hard, and at the same time retain its ductile quality. A very great amount of this metallic alloy is employed in the manufacture of tea-table ware. It is first made into sheets; these are afterwards spun in lathes into the forms of tea, coffee, and milk-pots, cups, flagons, and urns, of tasteful designs; after which they are electro-plated with silver, and become beautiful in appearance. Twenty years ago all our pewter and Britannia ware was imported from England; now very little, if any, comes to us from abroad. We manufacture all we use at home. Skillful English artisans introduced the art among us, and there are very large manufactories for making this ware in Waterbury and Meriden, Conn, Taunton, Mass., and several other New England towns. Very great advances have been made of recent years in the designs or forms of articles formed of this ware. The old pewter tea pots and their adjuncts were models of ugliness in comparison with the same class of articles now manufactured. The adoption of classic models has wonderfully improved the tastes of our people, and such has been the progress recently made in this art that elegant articles of such ware, with surfaces of dazzling pure silver, can now be purchased lower than the old pewterpots thirty years ago.

ENGRAVING ON GLASS.

The Scientific American translates from L'Invention the following account (by Mr. GUGNON) of a new process of engraving on glass, for printing the patterns for embroidery, netting, crotchet, etc., by which it is said that the labor of a month in this kind of engraving can be performed in one day. The process consists in etching by means of hydrofluoric acid which, as our readers are aware, has the remarkable property of corroding glass :

1. Substances Employed.—It is known that certain fatty and resinous substances are not soluble in hydrofluoric acid. Among these substances the author chooses the bitumen of Judea, to which he adds one-sixth part of gum mastic (mastic in tears;) he then reduces the whole to an impalpable powder.

2. The Design.-The design is cut in stencil, either in paper, parchment, or metallic plate, in a way to cover those portions of the glass which are to be attacked by the acid, and to leave exposed those parts which are not to be attacked.

3. The Application of the Process.-The glass is placed horizontally and varnished with a very thin coating of any fatty substance (the author prefers the essence of turpentine;) and the stencil plate is laid on the varnish while it is fresh. The asphaltum powder is then sifted through a very fine sieve over the surface of the stencil plate and the glass, and the plate is carefully removed, thus leaving the powder upon the glass in figures corresponding to the

open parts of the plate. The glass is next exposed to gentle heat which causes the essence of turpentine to combine with the asphaltum and the gum mastic, and the mixture, in melting, fixes itself to the glass.

4. Treatment by Acid.-The pattern is surrounded by a ridge of soft wax prepared for the purpose, and hydrofluoric acid, diluted with one-third its volume of water, is poured over it. In about 40 minutes the etching is completed.

MANUFACTURE OF ROOM OR WALL PAPER.

The manufacture of wall paper is carried on to a great extent in Philadelphia, and gives employment in some half-dozen establishments to 1,800 men and boys. The quality of the paper made there has a reputation which extends over the entire Union, and in many instances it is preferred for beauty and tasteful designs to that imported from France, Until within the last few years, all wall paper was made by hand; but now very pretty and cheap paper is produced by machinery in two of the Philadelphia factories. The mode of making paper by machinery and by hand is as follows:--The paper in the rough state, when taken to the manufactory for printing, is first coated with white clay, obtained from New Jersey. This clay is ground very fine and then made soluble. The paper is then passed over a revolving drum, the mixture being put on by a large brush, which revolves very rapidly. The paper, as it comes from the drum, passes into a heated box, which extends the entire length of the building, which completely dries it by the time it reaches that portion of the room. The factory of HOWELL & BROTHERS is 350 feet in length. If the paper is to be glazed, it is passed through rollers made of stiff bristles. This mode of prepar ing the paper is practiced in all establishments. It is then ready to receive the colors and figures which fancy may dictate. If the paper is to be printed with machinery, rollers having the figures, flowers, or any other design to be printed, fixed on them with small brass pins, the interstices being filled with felt, are placed in their proper places on the cylinder of the press, some eight feet in diameter. As many as ten different colors can be put upon the paper at one time, so accurate does the press work, and the registering apparatus being so perfect in all its details. There are two of these presses in the factory of HOWELL & BROTHERS. each one being capable of printing, 13,500 yards of wall paper per day. The paper passes up a plane and ther. under the press between that and the rollers which are to give it the various colors, after receiving which it passes through the heated boxes, and is then cut into pieces nine yards in length, ready for use. In other rooms the finer kinds of paper are made by hand. One is devoted to the making of velvet paper. Here the colors are put on with flat blocks, the workmen having a lever, moved by a treadle with the foot, to press the block so as to make the impression on the paper. It is then passed through a covered box, while the ink or color is yet wet, in which is a quantity of wool, ground very fine. A boy, by striking the bottom of the box with a stick, causes the paper to be covered with the wool, and when it is removed, the portions to represent velvet are nicely covered. In gilding paper, the same process, so far as printing is concerned, is followed. The gold is placed upon the damp portions of the paper by boys, and the particles which are brushed off are collected