COTTON AND SILK DYEING. According to Mr. Cam. Kcechlin, these fibers may be dyed in a solution made of—water, 20to 30 parts ; chlorate of potassa, 1 part; sal ammoniac, 1 part; chloride of copper, 1 part; Aniline, 1 part, and hydrochloric acid, 1 part, previously mixed together. The fabric or yarn is dried in ageing rooms at a low temperature for 24 hours, and washed afterwards WOOL DYEING OR PRINTING. Mr. J. Lightfoot prepares the wool by a kind of oxidation made as follows : 1 part f bleaching powder is dissolved in 10 parts of water. Then for 1 pound of wool, take about a pint of the above solution, dilute it with six gallons of water, and add 3 ozs. of muriatic acid. In uhis bath, which is at the temperature f f 100 Fan., work the wool during 20 or 30 ipnutes, and until it has acquired a yellonfeh tint. Then wait thoroughly and letit dty. Wool and laoMtes thws wcpcl may be dyed and printed in the usimj SILK PRINTING* la tnis ca silk is to be vegetablized (we have already the word animalized) by an im mersion in a bath of cellulose dissolved in am-moniacal copper oxide. We think this process quite delicate, on account of the action of ammonia on the silk. CALICO PRINTING. The first application of aniline black to cali co printing was made by Mr. John Lightfoot. One of the early printing mixtures was made of-Water, 51 qts. ; white starch, 1 It). 14 ozs.; chlorate of potassa, 6 ozs.; hydrochlorata of ani line, 1 lb.; sulphate or chloride of copper,5 ozs. jygg line and fast ; but the great quantity oFooggev employed was found to be injurious bctn to the fabric and to the metallic printing rollers. Subsequent experiments made by Messrs. C. Kcechlin, Cordillot, and Lauth, have led to the substitution of sulphide of copper for the sulphate and chloride of this metal, whose presence seems indispensable to the production ol aniline black. A good printing paste, which does not weaken the fabrics and does not corrode the scrapers and the rollers of the printing apparatus, is made as follows : Heat and digest—water, 1 lb. ; starch, 2 lbs.; sulphide of copper, 8 ozs. On the other hand, mix and heat—torrefied starch, 2 lbs. 6 ozs. water 4 lbs.; gum tragacanth water, 1 qt.; hy-drochlorate of aniline, 1 lb. 9 ozs.; sal ammoniac, 3- ozs.; chlorate of potassa, 9 ozs. Then mix the two compositions, print,and expose the fabric in the ageing room for 24 hours, and at a temperature from 77 to 104 Fah. Here is another paste by Mr. Ka'ppelin: Starch paste, 2- gals., chlorate of potassa, 7 oz. ; gum tragacanth water 5-* lbs. ; sulphide of copper 14 ozs. ; sal ammoniac, 9 ozs. ; a salt of aniline (tartrate) 2-- lbs., which is added last. Tartrate of aniline does not corrode the steel scrapers, and is gradually transformed into hy-drochlorate of aniline by the sal ammoniac of the mixture. Nitrate and hydrochlorate of aniline are the only salts of aniline which can produce the black After 24 hours' standing in the ageing room, the prints are drawn through a bath containing 2 per cent of carbonate of soda, steamed, and washed. Acids will turn the color to green, but alkalies will restore i the black. A solution of bichromate of potassa intensifies the color ; but an excess of this salt is apt to impart a reddish hue. The best aniline for black is the one which contains a mixture of aniline and toluidine, and which is sought for in themanufacture of reds. The sulphide of copper is made by dissolving at the ordi nary temperature 2 parts of sublimed sulphur in 2 parts of caustic soda, at 38 Baume. After 24 hours' standing and frequent stirrings, the solution is complete, and is thrown into a warm solution of 10 parts of sulphate of copper in 250 parts of water. The precipitate is washed and drained until about 10 pints are obtained, each pint therefore corresponds to 1 pound of sulphate of copper. Lucas paste.—It contains acetate of copper and hydrochlorate of aniline, without sal-ammoniac, and has been submitted to a peculiar process. When used, this paste is mixed with 6 to 8 times its volume of starch paste. The temperature of the ageing room is about 104 Fah. Paraf's paste.—It is a mixture of hydrochlorate of aniline, chlorateof potassa, hydrofluosilicic acid, and a thickening. It produces a very fine black when applied with copper or brass rollers, which furnish the copper necessary to the development of the color. If no copper is present, the shade is only a dirty blue. All these aniline blacks are remarkable as being very fast, unalterable by acids or alkalies, and even by chlorine to a certain point. If chlorine is not used in great excess, the black color will reappear ; if in excess, the color remains fallow. Aniline black may also be printed simultaneously with madder and most steam colors. All the compositions for producing aniline black must be acid, and the more acid there is, the more rapid is the produc- tion of the black. We ought, however, to remain within proper limits, otherwise the fiber may be weakened. The degree of acidity of the paste will also vary with the thickenings employed. Gum Senegal requires more acidity than torrefied starch, and the latter more so than white starch or gum tragacanth. In printing aniline black care should be taken not to print upon, or too near other places previously mordanted ; the mordant would be acted upon, and if it contains acetic acid, this acid once liberated would p*"event the formation of black, which will be only gray. There is also danger of spontaneous combustion, so rapid is the oxidation going on, when the printed piece is allowed to remain folded and wet. It should be immediately spread out in the ageing room. —Dictionary of Dyeing and Calico Printing. Improvement in Steam Generators, and in Steam Engine Valve Devices. The portable engine which forms the subject of this article, has attracted considerable attention from the simplicity of its construction, and its efficiency. It is an ingenious method of applying principles in steam engineering acknowledged to be theoretically correct,but always considered as practically difficult of attainment. The three prominent features of this engme are, first, the placing of the cylinder within the steam dome of the boiler, second, the construction of the boiler; and, third, the cutoff valve ; the latter being the subject of special patent, as well as the boiler. The inventor, Mr. Wm. Baxter, of Newark, N. J., has employed some novel applications of mechanical principles in the perfection of this engine, exhibiting a fertility of device which sustains the reputation acquired by his improvements in other fields of invention. Fig. 1, is a perspective view of the engine and boiler combined, with the valve improvement attached ; the construction of which will be easily understood by reference to Figs. 2, 3, and 4, which respectively represent a vertical section of the steam generator and elevations of the working parts of the engine, represented in a somewhat simplified form to show the main features more clearly, and to aid in its description. The heated products of combustion rise from the grate, spread in the combustion chamber, A, Fig. 2, descend through the vertical flues, B, into the gas chamber, C, then again ascend through the smoke chamber D,and finally escape through E. This smoke chamber is formed by an external cylindrical jacket extending entirely around the boiler proper, rising and contracting to meet the boiler below the water ling as shown in the engraving. The water envelops the top of the combustion chamber, A, and fills the space between the descending flues and the smoke chamber, and also between the flues and the combustion chamber, surrounding the flues, and covering the top plate of the gas chamber; thus securing a very large heating surface in an extremely compact manner, and leaving ample space in the steam dome, in which the cylinder is placed vertically, as shown in the engraving. The cylinder is attached to a circular bed plate, which also forms a cap to the steam dome. The pillars sustaining the crank shaft and its attachments also rest upon, and are bolted to this bed plate, so that in transportation the removal of the bolts which hold the bed-plate in position, separates the engine proper from the boiler, without disturbing the adjustment of the valve, or otherwise affecting the relation of the working parts. These parts are shown in Figs- 3 and 4—at least such as are essential to this description; the fly wheel and a portion of the crank shaft being, broken away to admit of enlarging the parts desired to be shown. Fig. 3 shows the bed plate, H, above mentioned with the cylinder and valve in place, and the peculiar and novel device designed lo act as both a regulator and cut-off. The valve, F, has a sleeve, G, attached to it, which plays j vertically through a stuffing box in the bed plate, H. This sleeve with the main valve, F, is driven by the eccentric, I. Through the sleeve, G, plays a connecting rod, J, which works the cut-off valve, K. The rod, J, is attached to a piston, L, Fig. 4, which plays in an oil cylinder, M. The spaces on either side of the piston, L, communicate with each other through a port, N, in the wall of the oil cylinder. The oil cylinder, M, is further connected by the rod, O, with the eccentric, P, Fig. 3, which imparts motion to M, and through it to the piston, L, the rod, J, and the cut-off valve, K. The cylinder, M, is filled with oil, which, when the port, N, is fully opened, is transferred from one side of the piston, L, to the other at each stroke, so that the latter will move the cut-off valve, only when it reaches the top or bottom of M ; but when this port is partially cut off by the sere w valve, S, Figs. 1 and 4, so that the power required to force the oil through the port is greater than that required to move the cut-off valve, K, the latter moves before the oil in M has been all passed through the port, N, and the steam may thus be cut off at any part of the stroke, by the proper adjustment of the screw valve, S. The action of this cut-off is so delicate that the slightest turning of S affects the movement of the engine, which may be as readily stopped by the closing of the port, N, as by shutting the throttle valve, since the closing of this port makes the cut-off valve cover either port in the principal valve, F, at precisely the time when it otherwise would begin to admit steam to the cylinder. Whenever also the motion of the engine has a tendency to accelerate by the sudden throwing off of belts or any other cause, the oil cylinder, M, and its piston act as a governor, since any acceleration of ths crank shaft is at once communicated through the eccentric, P, Fig. 3, to the cylinder, M, and as the power required to force a given quantity of oil through the port, N, increases relatively to the velocity with which it is moved, the piston, L, is moved more rapidly than before the acceleration, and cuts off steam sooner. The valves are held to their seats by the simple pressure pf the steam in the boiler, as shown in Fig. 3, The arrangement of the parts gives a very compact and neat appearance to the engine ; and the construction of the boiler, together with the immersion of the cylinder in steam of the same temperature as that which enters it, enables the inventor to use the method of expansion to great advantage. The result is a very economical use of fuel. We are informed that an engine cutting off at quarter stroke, and driving machinery to the extent of 4-horse power, consumes only 80 lbs. of anthracite coal per working day of 10 hours, a result sufficiently reniarkable but which is well attested. The patent on the steam generator was granted Oct. 27, 1868, but a reissue bearing date April 20, 1869, has been obtained. The patent on the improvement in steam engine valve was also granted Oct. 27, 1868, and reissued April 13, 1869. Communications may be addressed " Baxter Wrench Co.," Nos. 23, 25, and 27, Lawrence street, Newark, N. J., where this engine may be seen.