OLMSTED'S STOVE FOR BURNING AN

THRACITE (WELCH COAL)

The first figure on the preceding page represents a section of a stove for burning anthracite or Welch coal, which has been patented by Denison Olmsted, of New. haven, Connecticut, and is thus described in the inventor's specification, published in the Franklin Journal for June last :

"For generating the heat, I employ an anthracite coal stove, of ordinary construction, so far as relates to the chamber of combustion; but I prefer one made of sheet or cast iron (I at present use sheet-iron), lined with fire-brick, or lute. For distributing the heat, I use, instead of the open iron pipe generally employed for that purpose, a peculiar kind of apparatus, which I call a radiator, constructed as follows:

"A radiator consists of two concentric cylinders of iron, either sheet or cast iron, between which and around the inner cylinder the heated current proceeding from the stove circulates. Calling the outer cylinder A, and the inner cylinder B, their connexion or arrangement may be thus described :-A, be. ing a cylinder of any required dimensions (as, for example, 24 by 9 inches), and B a similar cylinder, but of smaller dimensions (as, for example, 21 by 5 inches), the two are placed upright; the top of B is brought to a level, or in the same plane, with the top of A (although it is not essential that they should be in the same level at top, but this is the common construction), being situated within it, and concentric with it, and reaching to within a few inches of the bottom of A. The inner cylinder B is closed at bottom, but open at top. The circular ring, or space, between the two cylinders at top is closed, and a partition is inserted up and down on opposite sides of the inner cylinder, and the whole length of it, dividing the space between the two cylinders into two parts, so that the heated current, before mentioned, may descend on one side, and ascend on the other.

"In order to distribute the heat from the inner cylinder, an air-pipe is inserted in, or near, the bottom, which penetrates both cylinders, and, being open at both ends, permits the internal air of the apartment to flow into B, as the air within B becomes rarefied by heat. Instead of the air of the apart ment, fresh air from another apartment, or from out of doors, may be introduced through the air-pipe, or the circulation of air through this pipe may be increased by elongating B upwards, by means of a pipe a'tached to it. A smoke pipe proceeds from the outer cylinder A, near the top, which communicates either directly or indirectly with the chimney.

"The radiator thus constructed being

connected with the stove before described, by a short pipe (the stove and the radiator usually stand side by side), the heated current, when the stove is in action, passes through this pipe into the radiator, descends between the two cylinders, flows into the inner cylinder B, ascends on the other side, and passes out at the smoke-pipe, near the top of the radiator.

"In order to remove such ashes as may be deposited from the heated current on the bottom of the outer cylinder A, a small opening, closed by a door, or plate, is made in or near the bottom of A.

"The stove above described is susceptible of various forms. The following are given as examples, viz.

"1. We may employ a single radiator. In this case, we may either have smoke-pipes attached to both the stove and the radiator, each being furnished with a damper to regu late, or to exclude, the draft; or we may have but one smoke pipe, namely, that communicating between the radiator and the chimney.

"2. We may employ two radiators, one on each side of the stove. From each radiator, and from the stove, pipes enter the flue of the chimney, either directly or indirectly, each pipe being furnished with a damper. A convenient arrangement is to place the whole apparatus, namely, the stove and radiator, or radiators, parallel to the breast of the chimney, on the hearth, for example; and the fire-place being closed, to let the three pipes enter by apertures, left so as to form an opening into the flue of the chimney.

"3. Where the communication with the flue of the chimney is made by means of a long smoke-pipe, the smoke-pipes from the radiators may be made to enter this pipe behind the damper, instead of entering directly into the flue of the chimney.

"What I claim as new in the stove just described, is the use of a drum or drums of peculiar construction, so combined with the part of the stove which generates the heat as to afford a new and very advantageous mode of distributing the heat.

"I do not claim any thing new in the structure of the stove, that is to say, the part that generates the heat, otherwise called the chamber of combustion; nor do I claim the use of concentric cylinders for distributing heat, as a new invention; but this peculiar structure of the drum, and its immediate connexion with the stove, as a substitute for the open pipe or pipes usually employed to distribute the heat generated in stoves for burning anthracite coal, I claim as a new and useful invention, being peculiarly economical, convenient, and efficacious.

"Description of the Engraving. "A, the outer cylinder of the radiator.

"B, the inner cylinder. "C, an opening by which air may enter the inner cylinder.

"D, space between the two cylinders, vertical partitions in which compel the draft to descend on the side next the stove, and to ascend on the opposite side, to pass off by the smoke-pipe E.

"F, stove of the ordinary construction."

CLUTE'S IMPROVED

PROCESS OF GENERATING HEAT FOR FORGING MALLEABLE IRON AND GENERATING STEAM TO PROPEL MACHINERY.

The second figure on our front page represents an apparatus for generating heat and steam, which has been lately patented by a Mr. Clute, of Shenectady.

We ex

tract the following description of it by the inventor from the American Railroad Journal:

"Where others than a cylinder boiler, or where more than one boiler is designed to be used, a given number of furnaces, of the description hereinafter set forth, are to be erected, under the same arrangement and in the most convenient form, to receive as many points of the boiler or boilers as, according to the principles hereinafter laid down, may be deemed most expedient. The cylinder boiler, however, I deem best adapted to the contem plated purposes of my invention.

"Where the cylinder boiler is used, the number and size of the furnaces will vary ac cording to the size of the boiler, and the quantity of steam required to be raised. The furnaces are to be built in a straight line, of uniform width and height, equidistant and continuous, the boiler to be laid horizontally or lengthways on the top of the furnaces. There is an aperture at either end of each furnace, through which the coal is shoved on the grate, and the fires fed as occasion requires. Under each grate there is a box, which I shall designate by the name of receiver, because it receives the blasts from the blow-pipe and the ashes falling through the grate. The receiver may be taken out and cleaned when necessary. Each receiver has at one of its sides an aperture for receiving a branch of the blow-pipe. There are, of course, as many branches to the main blowpipe as there are furnaces; and the blowpipe is connected with the bellows, which is worked by the steam which the heat of the furnaces generate. The branch blow-pipe enters the receiver about its centre, at a point equidistant from the grate and the bottom of the receiver, thus causing the wind in the receiver to circulate equally. There is an aperture near the top of the furnace, in the front, through which to protrude the iron to be heated.

"This aperture may be closed by a valve when not used.

"Suppose a cylinder boiler, 20 feet long and 24 feet in diameter; then there ought to be about seven furnaces, and the proportions of the different parts of the furnaces, &c., ought to be as nearly as may be as follows:Distance between the grate and the boiler, 12 inches; length of grate, 18 inches; width of grate, 8 inches; width of the furnace to correspond with the size of the grate; the aperture at either end to admit the coal, to be 8 inches and 6 inches in height; the receiver, 8 inches in width and 6 inches in height; aperture for receiving the blowpipe, 1 inch in diameter; aperture through which to heat the iron intended to be worked, 6 inches in width and 3 inches in height; distance between each grate, ths of an inch; diameter of blow pipe, 4 inches, and diminished to 1 inch at the entrance into the receiver.

"The strength of the blast required is equal to that of a blacksmith's fire. The degree of heat may be regulated by valves placed in the blow-pipe."

The inventor thus sums up the advantages which he anticipates from his appa

ratus:

"1st. The using a number of furnaces to raise steam; 2d, the process of heating the boiler uniformly at many points, thus differing from the universal practice which now obtains of heating the boiler at one particular point; 3d, the employing the same steam raised by the furnaces in driving the bellows connected with the furnaces; 4th, the application of the blow-pipe to ignite anthracite coal for raising steam; 5th, the using the same fire for the double purpose of raising steam and heating and working malleable iron.

"I consider these two last particulars the most important, and as in an especial man. ner distinguishing my invention from every other. This apparatus possesses a highly important advantage, in that it may be used for manifold purposes-for the manufacture of malleable iron into the different articles usually made by blacksmiths, and edge-tools, nails, &c.; and the steam-power may be applied to grinding and polishing the iron when manufactured, to propelling boats, driving a trip-hammer and mills of every description, and the other purposes for which steam-power is generally employed."

Description of the Engraving.

aa are the apertures for iron; bb, the grates; cc, receivers; dd, branches of main blow-pipe; e, the main-pipe; gg, cylinder boiler; hh, apertures for coal.

EXPERIMENTS ON INDIGO.

Sir, I have lately been engaged in a set of experiments on indigo; and as that substance is now so universally known as a permanent and beautiful blue dye, it may not be altogether uninteresting to your readers to give a sketch of its chemical characters, which are very striking and rather complicated.

Indigo of commerce is by no means a pure colouring principle. It contains a variety of foreign matter, part of which it may

have derived from the plant from which it was extracted, and part may have been added to it through carelessness in its preparation; of 100 parts, a good specimen will not afford more than 50 of real blue.

It is a matter of considerable importance to devise some simple, and, at the same time, economical plan of analysing this drug, not only for the purpose of ascertaining the exact quantity of colouring matter a given specimen contains, but also what is the nature of its impurities, which I have found to vary considerably in different sorts. In order to find the value of a sample with respect to its proportion of blue, Mr. Dalton proposes to dissolve one grain in sulphuric acid, transfer the solution into a tall cylindrical glass jar containing water, and then to destroy the colour by chloride of calcium, the value of the indigo being in proportion to the quantity of the chloride necessary to destroy its colour. I consider this to be, at best, a troublesome method, and not entirely to be depended upon. I made several experiments on two samples, one an excellent East India, and the other a very inferior Guatamala ; but the quantities of chloride of calcium required to destroy the colours were so nearly the same, that the superiority of the East India was not manifested.

Chevreul gives us a very good method of analysing indigo in the rough manner. He directs that it be first digested with water, which will take up 12 or 14 per cent., but the quantity varies much in different samples. The water acquires sometimes a yellow, but usually, especially with Guatamala's, a dark brown colour; this solution by exposure to the air precipitates flocks, having a green colour, which appear to be partly composed of indigo, becoming blue when left in the air; the greater part continues green, is soluble in alcohol and

solution of potash, but does not ever turn blue. I have found that this green matter, which is very slowly thrown down by the action of the air, is immediately and plentifully precipitated by dropping muriatic acid into a concentrated liquor; and in the specimens on which my experiments were made, the precipitate from the Guatamala was much more abundant than that from the East India; the liquor from the former was much darker than that from the latter, and it was remarked that the Guatamala was very inferior as a dye to the East India, yet the quantity of real indigo in each did not appear to vary much. I conclude, therefore, that the difference in quality was owing to a more than usual quantity of gluten and brown matter, and that these substances are more injurious than is generally supposed, tending to destroy the peculiar brilliancy of the indigo.

After water has extracted all that is soluble in that menstruum, Chevreul directs that the residue be treated with alcohol in successive portions, by which a further quantity of green matter is taken up, but so mixed with another red substance that it assumes a dark, ruby colour. Chevreul states, that 30 grains out of 100 are taken up by alcohol, which is rather more than I found. Lastly, muriatic acid takes up a further portion of red matter, together with alumina, lime, and oxide of iron; and pure indigo, amounting to 45 or 50 per cent., remains, usually mixed with a small quantity of silex.

When indigo is exposed to a temperature about equivalent to that of melting lead, it rises in the form of a beautiful purple smoke. This was known long before any attempt was made to obtain it in a crystalline form by sublimation. If, however, a proper apparatus is employed, and precautions adopted, it may be thus produced, and then assumes a very beautiful appearance. The best indigo for the purpose is that precipitated by agitating in contact with air the yellow solution of deoxidised indigo, which forms the dyer's blue vat; but where that cannot readily be obtained, common indigo may be used. In the latter case, 30 or 40 grains in coarse powder must be placed in a shallow metallic saucer, and a spirit-lamp applied to the bottom till the surface becomes covered with a copper-coloured, mossy-looking substance,

taking care to remove the source of heat the moment purple vapours appear. When the saucer is cool the crystals must be brushed off with a feather, and placed in another similar saucer furnished with a cover, so applied that the internal surfaces may not be more than half an inch apart. A second application of heat will cause the pure crystals to rise and plant themselves on the upper vessel, the impure substance remaining behind of a coaly appearance.

The crystals thus produced bear a very small proportion to the quantity of indigo employed. As an average of four experiments from 10 grains of impure indigo, I obtained by sublimation half a grain of crystals, and the residue weighed 6 grains, showing 3 grains of volatile matter to have escaped. The crystals volatised leave no residue. When they are viewed through a microscope, they appear as long, flat, acicular crystals, appearing red by reflected, and blue by transmitted light; they are not, however, always so, sometimes, particularly at the commencement of their formation, assuming the form of very thin plates, appearing almost opaque; indeed, when lying in a mass they always have a brown colour.

Sublimed indigo may be analysed by heating it with peroxide of copper in green glass tubes. Mr. Crum gives its ultimate constituents thus:

much reliance on my own discordant results. Organic analysis is a very delicate operation, and requires much experience and a peculiar apparatus, neither of which have I the advantage of.

In the year 1827, Berzelius published an excellent memoir on indigo. He found in it four peculiar substances, which constitute its chief ingredients, viz. Ist, a substance closely resembling gluten; 2d, a brown matter; 3d, a red matter (the resin of Bergman and Chevreul); and 4th, the proper colouring principle.

From a sample of good East India indigo I extracted the gluten by first boiling it with diluted sulphuric acid, then filtering and neutralising the acid by carbonate of lime, after which it was evaporated to dryness and alcohol boiled on the residue; this extracted a substance resembling gluten, and particularly characterised by its smell, which was very similar to broth. Gluten is itself a substance possessing properties in common with both the animal and vegetable kingdoms, hence it has been called a vegetoanimal substance.

The brown matter I separated from the residue left by the acid by gently heating it with a weak solution of potash, and from the residue again alcohol extracted the red matter. The alcoholic solution being evaporated to dryness, left a rubycoloured powder, which was dissolved by nitric acid, forming a fine Port-wine coloured liquor, which colour it did not long retain, but soon, in consequence of decomposition, turned yellow."

After these operations have been performed on it the indigo is not left in a state of purity; it contains, besides inso luble impurities, a portion of the green, red, and brown matter, but by acting on it by the protosulphate of iron and lime, and pouring the yellow solution of deoxidised indigo thereby obtained into diluted muriatic acid, a copious blue matter falls down, which, after washing, may be regarded as tolerably pure.

By acting on indigo by means of protosulphate of iron and lime, Liebeg produced a substance which he considered to be pure deoxidised indigo. The proportions I used in repeating his experiment were, 1,000 grains of the drug, 1,500 of copperas, and 1,600 of lime; these were put into a stone jar, and 3 quarts of water poured on them; the whole was then heated to 130° Fahr., and

so kept for 18 hours, guarded as much as possible from atmospheric air; the clear yellow solution was then drawn off by a syphon, previously filled with hydrogen gas and mixed with diluted muriatic acid, holding in solution a little sulphate of ammonia; a thick, white precipitate fell down, which was washed with water that had been boiled, and dried at the temperature of 212°; when quite dry it retained its white colour even when exposed to the air, but when moist it speedily became blue. To this substance Liebeg gave the name of indigogen, and he ascertained that in passing into the blue indigo it absorbs 11.5 per cent. of oxygen. The preparation of this substance, owing to its powerful affinity for oxygen, is extremely difficult, and it was only after repeated trials that I succeeded in producing it. It is absolutely necessary that all the vessels employed should be previously filled with either nitrogen or hydrogen, and the water employed be deprived of air by long boiling.

The action of some of the acids on indigo is extremely interesting. With the nitric acid it forms two distinct substances, according to the strength of the acid and the manner in which it is applied. When 1 part of indigo is mixed with 8 or 9 parts of moderately strong nitric acid, and boiled as long as nitrous fumes are evolved, carbazotic acid is formed. When the indigo is added to diluted nitric acid kept boiling, as long as effervescence continues, hot water being occasionally added to supply the loss by evaporation, indigotic acid is formed.

The particulars of the preparation of each are as follows:

To form carbazotic acid, I boiled some small fragments of the best East India indigo in ten times their weight of nitric acid; the mass frothed and swelled, give ing out a large quantity of nitrous gas, mixed with carbonic and prussic acids. It is recommended by some chemists to add successive portions of nitric acid whilst boiling; but there is nothing, I believe, gained by this. I have tried repeatedly both plans. The solution is bright yellow, and contains, besides carbazotic acid, artificial tannin, resinous matter (which forms a film on the surface), and indigotic acid-on cooling, carbazotic acid is freely deposited, but not in a pure state, mixed probably with a considerable quantity of indigotic acid;

the residual liquor, by evaporation and adding cold water, yields an additional quantity.

The crystals were dissolved again in hot water, which was divided into two equal portions, one of which was neutralised by carbonate of potash, and the other by carbonate of ammonia; carbazotates of potash and ammonia were formed, and repeatedly purified by crystallisation. The former salt appeared in the form of long, yellow, semitransparent, and very brilliant needles; the latter formed yellow, flattened crystals. Carbazotate of potash possesses the property of detonating when heated like fulminating silver; carbazotate of ammonia is fused and volatilised without decomposition. It may here be observed, that the sparing solubility of carbazotate of potash renders its acid an excellent test for potash. Carbazotic acid is easily sepa rated from the salts by the addition of sulphuric acid; its crystals are in the form of brilliant, yellow plates; it is extremely bitter, and said to be poisonous; it may be fused and volatilised without decomposition, but when exposed to strong heat it explodes, leaving a residue of charcoal.

By Liebeg's analysis this acid contains no hydrogen, but, as its name implies, it is a compound of carbon, nitrogen, and oxygen, in the proportions of 15 carbon, 3 nitrogen, and 15 oxygen. Others give different proportions, and Dumas found in it 14 per cent. of hydrogen. It may be formed by the action of nitric acid on many animal and vegetable substances, as silk, aloes, &c.

To form indigotic acid, indigo in coarse powder was mixed with nitric acid, diluted with an equal weight of water; carbonic acid and nitrous gas were produced, but no carbazotic acid; when effervescence had entirely ceased, it was allowed to cool; a thick, white precipitate fell down, which was boiled with oxide of lead, and filtered in order to separate the resin; the clear, yellow solu tion was decomposed by sulphuric acid, and filtered at a boiling temperature. Indigotic acid was deposited on cooling in minute, yellowish white needles; by repeatedly dissolving and re-crystallising, it finally assumed the form of a tuft of feathers. To purify these, Dr. Turner recommends digestion with carbonate of baryta, and subsequent decomposition_of