principle. A farther application of this mordant of caseine, oil, and lime is in the printing of stuffs; in this case we are not limited merely to mineral colors, which, by its aid, may be fixed upon the goods, but the numerous vegetable colors may likewise be very well applied, by first converting them into lakes by means of alumina or protoxide of tin, and then using these lakes in the same manner as the powdered mineral colors. After being printed, the goods are wrapped in moist linen, and left for about half an hour in the moist vapor in a warm atmosphere. During this time the impressed color does not dry superficially, but is absorbed into the interior of the fibres, and is then completely fixed in a subsequent drying.

This new method of mordanting has already had considerable influence upon several pigments, such as archil, which has only been used for dying exceptionally. By Broquette's process some very beautiful colors are obtained from it, modifications of the peculiar color of the archil by lime. It will be evident that in this process of dying it is requisite to pass the goods through a lime bath, which will not do for many dyes, as the colors have their tints altered by such treatment. In such cases magnesia is to be substituted for lime. When goods are printed with the mineral colors. or lakes according to the above process, very full colors are obtained, which, in the case of many patterns, is not desirable. To bring out the shades and half colors in the full colored impressions, the printed goods are placed with the colored surface upon an absorbing ground, and the forms pressed on the back. The printed portion pressed upon the absorbing surface is deprived of some of its color, and numerous patterns can be produced in this manner.

Translated for the Journal of the Franklin Institute.

New Process for Photography on Paper, by which Positive Pictures may by obtained directly. By M. F. BoUSIGUES. (Extracted by the Author.) Any very even, slightly sized paper, free from stains and metallic spots, may be perfectly well applied to this new process. The papers of Canson & Lacroix, of Angoulême, have given me the best results.

Three sheets are to be taken and dipped successively in distilled water, and stretched upon the glass of the frame, taking care to make them adhere at every point by means of a very fine linen. The one which appears best fitted to receive the impression from the light is to be placed upon the others; the latter serving only to maintain the adherence and moisture.

When this moisture has disappeared, three or four drops of neutral nitrate of silver must be let fall on the surface of the paper, and rapidly spread by means of a brush. The traces of this solution disappear in a few minutes, leaving nothing on the paper but the appearance of a light vapor. In this state the paper is to be treated in the same way as a metallic plate. The vapors of iodine, and of the bromide of lime, will give it great sensitiveness, but it will be necessary to expose it for a longer time to the vapors of this latter substance.

Here are such figures as I can give :-First iodizing 15 seconds; bromine 35 seconds; second iodizing 10 seconds.

The glass is then placed in the frame and exposed to light, which operates on the paper almost with the same rapidity as on the plate of silver. Mercury makes the image visible.

If the operation is well done, the exposure to light properly regulated, we obtain a positive image of a beauty comparable to that which the plate gives, and at least very superior in the softness of its tints to those by the ordinary process with gallic acid.-Proc. Acad. Sci., Paris, 28th Oct., 1850.

For the Journal of the Franklin Institute.

Description of the Naval Dry Dock at Brooklyn.

The stone dock at the Brooklyn Navy Yard being so far completed as to be used for the purposes intended, I send you the following description of it:

For pumping out the water they have a vertical beam engine, having a cylinder of 50 inches diameter, and 12 feet stroke; the beam is of cast iron, 32 feet long, and at the opposite end from the cylinder there is a connecting rod attached to the crank shaft, on which is a fly-wheel of 24 feet diameter. There are two single acting lifting pumps, (one being worked from each side of the beam,) lined with composition, 63 inches diameter and 8 feet stroke. The quantity of water to be removed is about 600,000 cubic feet, and the time occupied 3 hours; the smallest lift being 2 feet, and the greatest 26 feet. Connected to the engine are three drop flue boilers, so arranged as to be used singly or together, at pleasure. The cut-off valve used on the engine iş separate from the steam valves of the engine, and is so arranged that it may be adjusted at pleasure while the engine is in motion. The engine and pumps are a fine specimen of work, and were constructed by Mr. Kemble, at the West Point Foundry. B.

On the Economic Values of Coals used in the Collins' Tubular Boiler. To E. K. COLLINS, ESQ.,

Agent for the New York and Liverpool Steamship Co., NEW YORK, Dec. 24, 1849. DEAR SIR,-Having received orders from you to test, by experiment, the evaporative values of several kinds of Coal upon your "Vertical Tubular Boiler," and having discharged such duties, we hereby enclose you a copy of the report of said experiments with our views annexed.

Our first experiment was with the Dauphin Rattling Run. It possesses high evaporative power, with considerable cohesion of its particles, so that it may not be broken into too small fragments by the constant attrition which it may experience in the vessel. It ignites very quick with natural draft, burns with a clear bright flame, leaving but a slight soot deposit upon the tubes, owing to the free circulation of the air through the grate bars, rendering the combustion more perfect. In short, it requires little if any attention from the fireman until it is necessary to charge the furnaces with a fresh supply of coal.

Our second experiment was with the Baltimore Cumberland. It ignites rapidly, producing a strong heat; shortly after which time, it runs together, often adhering to the grate bars, requiring much time and labor to separate it. Without the strictest attention, in a short time, it would entirely exclude the air from penetrating through the interstices of the coal, thereby producing a great loss of steam. It has very small cohesion of its particles, requiring very careful handling to prevent it from crumbling into very small pieces.

Our third and fourth experiments were with "Young's Mining Company" and "Maryland Mining Company." They produce the same effect as the second experiment, the results being all forced.

Our fifth experiment was with the Erie-possessing rapidity of ignition, makes an intense fire, throwing off an immense volume of carbonaceous matter, causing the tubes to fur up in a very short time, also having an undue quantity of sulphur in it.

Our sixth experiment was with the Dauphin Rattling Run; varies nothing from the first experiment.

Our seventh experiment was with the "Maryland Mining Company;"

results as before.

Eighth experiment was with the Dauphin Backbone, slightly differing from the Rattling Run in evaporation and rapidity of ignition.

Ninth experiment was with the Dauphin Rattling Run; still retaining the pre-eminence for marine purposes over any of the coals submitted for trial, requiring less labor by 75 per cent.-producing more steam in less time than any of the coals experimented with.

Our tenth experiment was with the "Maryland Mining Company.' Experienced the same difficulty as before, viz.:-running together, forming a heavy compact crust over the whole area of the grate, requiring frequent raking that the air might circulate through and ignite the surface or top of the coals, thereby occasioning the furnace doors to remain open much longer than the circumstances of the case ought to justify.

Having given a brief review of the coals submitted to us for trial, it may be well to add, that the Dauphin Rattling Run (for marine purposes) meets our decided approval, from the experiments we have had of it.

We remain, dear sir,

Yours very respectfully,

(Signed)

NATHAN THOMPSON, JR.
JAMES THOMPSON.

138

Report of A. L. ROUMFORT, Superintendent Columbia and Philadelphia R. R., on the Experiments made with the Coal Burner, "Henry A. Muhlenberg."

SUPERINTENDENT'S OFFICE, Parkesburg, Nov. 27, 1850. To the Honorable, the Board of Canal Commissioners, Harrisburg, Pa.: GENTLEMEN :-The undersigned, Superintendent of Motive Power on the Columbia and Philadelphia Railroad, having been instructed by your Board to test, practically, the Patent Movable Fire Box, for burning Anthracite Coal in Locomotive Engines, invented by John J. DeHaven, respectfully reports:

That on taking charge of the Road, on the first of September last, he found the locomotive "Henry A. Muhlenberg," refitted for testing this experiment, which was done, as he was informed, by your order, under the superintendence of his predecessor, Colonel Wm. English. The improvement purported to consist: first, in the substitution of Anthracite or Bituminous Coal, as a fuel, for wood, in generating steam; thereby saving from 30 to 50 per cent. in the cost for fuel to the State. And secondly, in constructing a detached and movable Fire Box, entirely separate from the Engine and Boiler; and in such a manner, by the use of flanches, bolts, and connecting pipes, as to attach it to a Boiler, and detach it when necessary for repairs, in a space of time not exceeding twenty-four hours. This latter, (which is the particular improvement covered by DeHaven's patents,) was designed to remove the great objection to the use of Coal Burners, in generating steam, both in Locomotives and Marine Boilers: viz. the loss of time necessarily incurred in the frequent repairs of the fire box.

It has been satisfactorily ascertained, long since, that in this section of the country, where wood as a fuel is more costly than coal, and becoming more so annually, that the use of coal in the generation of steam, would be a large item of economy. And accordingly, within the last ten years, experiments made on our principal Railroad and Steam Navigation Lines, have proved to a demonstration, that coal can be used for the purpose of generating steam, in such a way as to be entirely satisfactory, and with a saving of from 30 to 50 per cent., according to the relative value of wood and coal.

The obstacle, however, in the way of its general introduction, has been found to consist in the fact, that the heat produced by coal, being more intense in the fire box than that of wood, this intense heat, together with the chemical action of the coal upon the lining of the fire box, destroyed it, in a comparatively short period of time; and that although the great saving in the first cost of fuel, made the actual cost of the repairs of the fire box, no object; yet, the loss of time occasioned by those frequent repairs was, and still is, a serious evil. For instance: a coal burner in full active duty, may burn out her box in from 6 to 18 months, according to her capacity and service. It would cost from $500 to $1000 to repair her. This cost, however, is much more than made up by the difference of the cost of coal and wood; but the time consumed in making this repair, would involve a loss of from four to six weeks on a locomotive, when the engine required no other repairs.