ART. XXXIII.-Description and Analysis of a Meteoric Stone that fell in Stewart county, Ga. (Stewart county Meteorite), on the 6th of October, 1869; by J. LAWRENCE SMITH.

IN October, 1869, I learned through the public press that certain meteoric phenomena had occurred in Stewart county, Georgia, and that one or more stones had fallen. Enquiries were immediately instituted by me, and, through Prof. Willet, I obtained for examination the only stone found, one that was seen to strike the ground, and from him received an account of the phenomena observed at the time by Messrs. Latimer, Clarke and others. [See preceding Article.]

It

The stone, as it reached me, was nearly intact, and weighed 12 ounces; it must originally have weighed 12 ounces. is of an irregular conical shape, having a flattened base, and is covered with a dull heavy black coating. The specific gravity is 3-65. The fractured surface has a grayish aspect, and when examined closely, especially by the aid of a glass, exhibits numerous greenish globules with a whitish granular material between; through the mass are dark particles consisting principally of nickeliferous iron, with some pyrites, and a few specks of chrome iron. The nodules are sometimes three or more millimeters in diameter, and of an obscure fibrous crystalline structure, the crystals radiating usually from one side of the nodule; they have a dirty bottle-green color, a greasy aspect when broken, and are more or less opake.

Some of these little nodules were separated in a tolerable state of purity, amounting to 121 milligrams; on analysis they afforded:

The hardness of the mineral is about 6, and it is quite tough. The formula would be Rsi, with a part of the silica replaced by alumina, a not unfrequent case in minerals such as hornblende, hypersthene, &c. As it is impossible to derive any light from its crystalline structure, the above analysis warrants me in concluding that it is either bronzite, or hornblende, but I am more inclined to the former supposition as it appears to take the place of the enstatite in many meteorites.

Nickeliferous iron constitutes about 7 per cent of the mass,

and a portion separated in as pure a state as possible, afforded on analysis

These are the proportions after allowing iron for a small amount of sulphur, present in a minute quantity in the nickeliferous iron, which could not be separated mechanically. I did not test for copper or phosphorus; the quantity of iron separated from the stone did not warrant my making special analyses for substances, the quantity of which present could only be exceedingly minute.

The stony matter freed from the iron was treated with nitromuriatic acid and water, and heated for some time over a water bath, renewing the water and acid once or twice; the solution was filtered, and the residue washed; the residue was then treated with a warm solution of caustic potash, filtered and again washed. The filtrate was neutralized by hydrochloric acid, and added to the first filtrate, and the whole evaporated to dryness over a water bath, warmed gently over the lamp, and treated with water and a little hydrochloric acid, thrown on a filter, the silica collected and estimated; the last filtrate was treated with a solution of hydrochlorate of baryta to ascertain the quantity of sulphuric acid present, (due to the pyrites in the original mass); it was found to indicate 6.10 per cent of magnetic iron pyrites. The solution freed from the excess of baryta was now analyzed in the ordinary way.

The insoluble portion of the meteorite was fused with carbonate of soda and a small fragment of caustic potash, and its ingredients ascertained.

A separate portion of the stony part of the meteorite was examined for alkalies.

The various analyses referred to above gave-omitting the nickeliferous iron:

The soluble part consists principally of olivine. The insoluble is doubtless the bronzite already refer to, with a little albite or oligoclase.

Chrome iron was detected by fusing some of the stony part of the meteorite with carbonate of soda and a little niter, and separating in the usual way. The quantity was quite minute. The composition of the stone as made out would be

ART. XXXIV.-Some practical remarks on the use of Flame Heat in the Chemical Laboratory, especially that from burning gas without the aid of a blast; by J. LAWRENCE SMITH, Louisville, Ky.

THERE is probably no more important era in the operations of the chemical laboratory than that of the introduction of the lamp as a source of heat for a large number of chemical operations, and that without the aid of a blast. Berzelius was doubtless the first to accomplish much in this direction, which he did by the agency of the lamp that so commonly bears his name, and which, more or less modified, is still in use where the ordinary illuminating gas is not to be had.

Although illuminating gas has been in use for about seventy years, it is only within a comparatively recent date that it has been pressed into service, and used as a heating agent in the laboratory. The reason of this arose from the fact that when burnt in the ordinary manner it deposited soot on the vessels heated by it. This difficulty has been overcome by burning the gas from small orifices made in a tube bent in the form of a circle, the holes being from 1 to 2 centimeters apart, and, sometimes, combining two or more rings in concentric circles. This method, however, has not been generally adopted.

We must date the successful introduction of gas for heating purposes to the use of a mixture of gas and air passed through wire gauze and ignited above the gauze, giving a flame without light and with great heat; the invention of this method is

claimed by several, and doubtless was discovered by different individuals at about the same time, without a previous knowledge of each other's results; this method is still more or less employed for certain purposes.

The next step in this direction, and doubtless the most important up to the present time, is to burn the mixture of gas and air without the agency of wire gauze; it was first made known to the public in the burner commonly called the Bunsen burner, doubtless from its being either invented or brought into extensive practical use by the distinguished chemist of Heidelberg. Its form is too well known to require more than a mere mention here, and it is now made of all sizes from those capable of burning 4 cubic feet of gas and under, to those which can burn 15 or 20 cubic feet from a single burner, or from a combination of several smaller ones. To this burner, some material'additions have been made by different individuals. J. J. Griffin, (the chemical instrument dealer in London), was, I believe, the first to introduce the use of the rosette and the regis ter for the supply of air. The most remarkable results accomplished by this method of burning gas and air are those obtained by G. Gore of Birmingham, (all of whose results I have verified), where gold, copper, cast iron, &c., were fused in crucibles without the agency of any artificial blast. Mr. Gore evidently realized fully the true principle of burning this mixture, so as to obtain a maximum effect; the burner, however, with its furnace arrangements, is unavoidably of a form and on a scale limiting its application.

The usual form of the Bunsen burner, with the rosette and register (when required), bids fair to hold its own against any other form for general purposes, and whatever modifications may be made on it should be of such a character as not to entrench on its simplicity. One or two of these modifications are now in daily use in my laboratory, for which there is no claim. to any special originality, nor are they intended to supplant the ordinary form.

As simple an instrument as the Bunsen burner appears to be, its principles and effects are well worthy of being carefully studied.

As the gas passes from the small orifices* in the lower part of the burner, and mixes with the air drawn in at the lower opening, and passes out at the open end of the tube, it usually contains not quite enough oxygen for its complete combustion, and requires free access of air to the outer portion of the flame

*The outlet for gas may be in the form of crossed slits or two small holes of (1-32 inch diameter each) for the small size burner, the length of tube being about 4 to 4 inches long; the next larger has four openings (about 1-25 inch diameter each) and the tube about 5 inches long.

to complete the combustion; yet even with this, the flame is hollow in its lower portion, having a cool center, its most intense heat being at about three or four inches above the end of the tube in the smaller Bunsen-burners, and eight or ten inches in the largest size. If a proper access of air is not allowed to . the flame, as sometimes happens in some of the furnace connections occasionally used with Bunsen's burner, acetylene is formed from the imperfect combustion, which is recognized by its disagreeable odor, or by collecting some of the gas formed during the combustion; the presence of acetylene may be rendered evident by a small amount of a solution of ammoniacal cuprous chlorid.

The best heating effects of the gas used in the ordinary round Bunsen burner, when employed in the heating of crucibles and other vessels, are not obtained; yet in the great majority of cases the small loss of gas is not worth considering, especially as to obtain better results in most cases, would only complicate this beautifully simple instrument.

1.

To get the best effects of heat, we must imitate the principle applied in the Argand burner, namely to flatten down the exit of the mixed gases. It was by following out this principle that Mr. Gore was enabled to make a burner having a number of radial flat orifices as represented in the figure (1), the air from without having free access to the flame along the entire length of the slit openings, the number of slits used are more numerous than those represented in the figure. With the flame from this burner introduced into a certain form of refractory cylinders, cast iron can be melted in a crucible, without the aid of a blast, as has already been stated; the little chimney to the furnace being two inches in diameter, and four feet long. This burner and its furnace is of but limited application, and the amount of gas consumed considerable.

The openings at the exit of Gore's burner.

The principle, however, of the above burner is introduced in constructing a more simple form, and the flattened orifice is now used in the construction of what I conceive to be the best form of furnace for heating glass tubes for organic analyses and other purposes; such furnaces are made by Weisnig of Paris, and Desaga of Heidelberg.