The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A das!! denotes, that the result is include The next following observation,

REMARKS.

Second Month.-17. A fair day, with Cumulostratus: rain by night. 18. Fine and spring-like: Cumuli capped with Cirrostratus, a.m.: very stormy night. 19. After a squall in the morning, a very fine day, with large Cumuli and Nimbi: a full bright rainbow at three, p.m. : the wind settled by evening. 20. Hoar frost: very fine morning, p. m. : large ramified Cirrus mixed with Cirrocumulus at a great height: Nimbi: some violent wet squalls in the night from the southward. 21. Large Cumuli, and much wind: showers. 22. Wind shifted to N: cloudy morning: Cumulostrati by inosculation. 23. Wind and rain: of the latter, 0.35 in. between six and nine, and 0.27 in. more by noon: afternoon, a gale, with much cloud: evening more settled. 24. Fine morning: at noon, lofty large Cumulostrati, with bright sun: in the course of the afternoon, au obscurity, like the crown of the Nimbus, came down upon these clouds; and a considerable fall of snow took place before dark, with wind. 25. Snowy morning: the hills white with snow; which soon vanished before a bright sun, p. m. 26. Cirrocumulus above, while the ground and water are frozen: about half-past ten, a faint, but large solar halo, which continued till near 11, when obscurity came on from the southward, followed by drizzling rain, p. m. 27. Overcast morning: rain in the night. 28. Cloudy: some rain.

Third Month.-1. Snow and sleet, a. m.: a wet day. 2. Wet morning: cloudy, drizzling day. 3. A moderate easterly gale, with much cloud: a gleam of sunshine, p.m. -18. There has been scarcely any rain since the 4th; the sky mostly grey, with light clouds; at times overcast, or filled with Cumulostratus : the wind northerly, breezes, and the air drying; so that the roads at the close of the period, notwithstanding some very light showers of late, remain considerably covered with dust. The diverging bars of light and shadow, produced by the sun's rays passing through the interstices of clouds, have been several times exhibited within these two days.

Second Month.-(Feb.) 16.—In the observations on the barometer, for the figures at present in the columns, read max, 29-70. med. 29.535; and in the results of the barometer, the mean of the period 29.522 inches.

Researches on a new Mineral Body found in the Sulphur extracted from Pyrites at Fahlun." By J. Berzelius.*

1. Fabrication of the Sulphur at Fahlun. Phenomena exhibited when this Sulphur is employed for making Sulphuric Acid. PYRITES, which abound in different parts of the copper-mine, are employed at Fahlun for the preparation of sulphur. They are often mixed with galena, blende, and several other foreign bodies. They are placed on a layer of dry wood, in long horizontal furnaces, the upper part of which is covered with earth and with decomposed pyrites. The smoke passes from the furnace into horizontal chimneys, the first portion of which is constructed of brick, the last of wood. The wood is kindled below, and the heat causes the excess of sulphur to distil from the undermost stratum of pyrites. The sulphur in the state of vapour is carried off by the hot air, and afterwards deposited in the chimney in the form of flowers. When the wood is consumed, the protosulphuret of iron begins to burn, and to drive off the excess of sulphur from the stratum immediately above it. In this way the operation goes on till the pyrites are entirely burned. The powdery sulphur produced by this process contains a great deal of sulphuric acid. It is washed in water, fused and volatilized again in order to purify it. The fused sulphur before it is redistilled is a greenish grey mass, with a radiated fracture; and heterogeneous substances may be seen

• Translated from the Ann, de Chim, et Phys, ix, 160, (October, 1818.)* VOL. XIII. N° VI.

2 C

mixed with it. The sulphur prepared during winter cannot be washed without considerable expense. It is, therefore, melted without depriving it of the acid with which it is impregnated. When the fused mass is broken and exposed for some days to the air, very acid drops exude from it, containing sulphuric acid, arsenic acid, and sulphates of iron and tin.

When this distilled sulphur is employed to fabricate sulphuric acid by combustion, it deposits in the bottom of the leaden chamber a reddish powder. This circumstance had been long observed by M. Bjuggren, who was possessor of the sulphuric acid manufactory at Gripsholm. He found that the deposite was not formed when any other kind of sulphur was employed; and having been informed by a chemist that the red matter must contain arsenic, he gave over employing the sulphur of Fahlun.

Since the manufactory was purchased by MM. Gahn, Eggertz, and myself, we have always burned the sulphur of Fahlun. The red sediment which formed in the liquid acid always remained at the bottom of the chamber, and had increased so much in quantity as to form a stratum about a line in thickness. The operation by which the sulphur is acidified in this manufactory differs from that which is usually employed in this respect, that the sulphur is not mixed with nitrate of potash. Flat glass plates are put at the bottom of the cistern containing nitric acid. The sulphurous acid by decomposing the nitric acid produces the nitrous gas necessary for the complete acidification of the sulphur. This modification of the process was introduced by Mr. Gustavus Schwartz, when, after the diminution of the size of the leaden chamber, the ordinary method failed entirely in producing sulphuric acid. The method of Mr. Schwartz is more expensive; but it produces a purer acid; for while we find five or six per cent. of foreign substances in English sulphuric acid, that of Gripsholm never contains more than two per cent. and that merely sulphate of lead.

In the glass vessels which contain the nitric acid, we find, after the complete decomposition of the nitric acid, a concentrated sulphuric acid, at the bottom of which is deposited a red or sometimes a brownish powder. This powder excited our attention, and induced us to examine its nature more particu larly. The quantity of it, resulting from the combustion of 250 kilogrammes of sulphur, did not exceed three grammes. The principal part of it was sulphur: it took fire, and burned like that body; but it left a bulky ash, which, when heated before the blow-pipe, gave out a strong smell of horseradish, analogous to that which Klaproth says is produced when tellurium is treated in the same way. After the smell ceased to be produced, there remained a metallic globule, which was merely lead. To separate the tellurium supposed to be contained in it, the reddish matter was dissolved in nitro-muriatic acid. It left a quantity of sulphur undissolved. The liquid, being mixed with

2

a slight excess of caustic ammonia (which does not dissolve oxide of tellurium), let fall a white precipitate, which, when treated by the blow-pipe, gave out a strong smell of tellurium, and left a metallic globule of lead. The quantity of the precipitate was too small to extract tellurium from it; but we considered it in consequence of its smell of horseradish as a tellurate of lead. The -liquid which had been saturated with ammonia, being evaporated to dryness, detonated, and was dissipated without any other residue than some black stains on the platinum crucible employed in the process.

2. More particular Examination of the Substance which emitted the Smell of Horseradish when the Reddish Matter was burned. Experiments to obtain it in a separate State.

The appearance of a substance so rare as tellurium in the sulphur of Fahlun, induced me to endeavour to obtain it in a separate state, in order to be able to form more accurate notions respecting it. I, therefore, took out the whole mass which was at the bottom of the leaden chamber. While still moist it had a reddish colour, which, on drying, became almost yellow. It weighed about 4 lbs. It was treated with nitro-muriatic acid, added in such quantity as to make the mass into a pulp; it was then digested in a moderate heat. Its colour changed by degrees; the red disappeared; and it became greenish yellow. After 48 hours' digestion, water and sulphuric acid were added, and the whole was thrown on a filter. The liquid which passed through had a deep yellow colour. The mass remaining on the filter had not sensibly diminished in bulk. It consisted chiefly of sulphur mixed with sulphate of lead and with other impurities. A small quantity of the filtered liquid was taken to find out the method of separating the substance which it was presumed to contain. This portion was precipitated by ammonia. The precipitate being well washed and dried, mixed with potassium and heated in a barometer tube, was decomposed with ignition. When put into water, a portion of it was dissolved, and the liquor assumed a strong colour of beer, very different from the wine-red colour communicated by hydrotelluret of potash; but after some hours, it became muddy, depositing red flocks, the quantity of which increased on the addition of nitric acid. This precipitate was collected, and when a part of the filter on whic'. it was deposited was burned, it gave the circumference of the flame a blue colour, and emitted a very strong smell of horseradish. A portion of pure tellurium precipitated in the same manner from a solution of hydrotelluret of potash had a grey colour, gave a green tinge to the circumference of the flame, and emitted no perceptible odour of horseradish! On examining more closely the purified tellurium, which had served in my former experiments on the oxide of tellurium and on telluretted hydrogen gas, I found that it produced no odour, neither when

1

2 € 2