« PreviousContinue »
be considered to differ essentially from them. For the information relative to their component parts, I am entirely indebted to the skill and knowledge of our celebrated countryman, Mr. Myhlensteth, who has had the goodness to make an accurate chemical analysis, not only of the various kinds of lava, but of the fine whitish substance resembling salt, which has been before mentioned, and also of various other substances, one among which deserves particularly to be noticed, a kind of ravelings, which resembles grey hairs. This was to be found every where in the vicinity of the fire, but especially on level sandy places, and no where in so great quantity as on the extensive sandy plain of Skeidarasand, to the eastward of Nupsvaters and Fliotshverfet. The filaments sometimes lay spread out singly upon the ground; sometimes mixed and interwoven with each other; in other places, twisted by the action of the wind into the form of garlands of various sizes, or into circles of a light grey color. The ravelings themselves, though short and broken, resembled the finest hair,
The following is the result of Mr. Myhlensteth's experiments upon the five different kinds of volcanic substances which were sent to him, and which have now been mentioned:
No. 1 resembles externally the scum of iron. Two ounces of it being pulverized, one ounce of iron was extracted from it, by means of the loadstone, and was perceptible, with a magnifying glass, in small thin laminae, to which some lava was still attached. These two ounces were put into an equal quantity of oil of vitriol, mixed up with it, then thinned with eight parts of water. The vitriolic acid evidently dissolved the iron, when the solution was separated, which, at blood-heat, afforded a fine Prussian-blue color. The remaining part, that was not dissolved by the vitriolic acid, was thoroughly dried and found to have lost three quintins of its weight, and the loadstone had no effect upon it. Another experiment was tried with one ounce of this mineral, from which the magnet only extracted one and a half quintin, and the vitriolic acid dissolved only twenty-four grains of it.
No. 2. A mass of matter melted and run together, colored on the outside with red and green. It consists of sulphur, mixed with iron, copper, sand, and other kinds of earth which contain some acid of salt. If a piece of it is put into a moderate coalfire, and thoroughly heated, it gives a very fine blue flame. Ten quintins of it were made red-hot in the fire, pulverized, mixed with an equal quantity of oil of vitriol, and diluted, during the operation, with eight parts of water. After some hours, the solution was separated, and gave a fine coppercolor to a piece of polished iron. To this solution was added as much iron as could be dissolved, for the purpose of separating the copper, which, on being afterwards melted, was found to weigh fifteen grains. This copper yielded readily to the hammer, and with the addition of spirits of sal ammoniac afforded a very bright blue color. To the sediment, still undissolved, was again added half as much vitriolic acid, and the whole was treated in the same manner as before. The solution was then precipitated at blood heat, and afforded one quintin of Prussian blue. The still remaining sedi
ment, when dried, weighed eight quintins, and consequently the acids had extracted one quintin and forty-five grains of iron, and fifteen grains of copper. The remaining eight quintins, when melted down with borax, gave a clear black glass, without regulus.
No. 3. A white kind of calcined earth, one ounce in weight. It caused an astringent sensation upon the tongue. On being put into boiling water, half a quintin of copper vitriol was extracted from it.
No. 4 was to all appearance nothing but common lava, and, as far as could be ascertained, consisted of sulphur ore mixed with iron, a little copper, and various kinds of earths, melted down together. The mineral acids had no effect upon the lava, and, on its being pulverized, a very small quantity of iron only was produced. Four small pieces, weighing three and a half quintins, which appeared to be more light and brittle than the rest, and totally free from white spots, were melted down with borax, when they yielded a lump of copper weighing three and a half grains. Half a pound of this lava was pulverized and properly melted, but it gave no more than three grains of copper.
No. 5 was a piece of common pumicestone.
Of the whitish powder, with which the cavities of the lava were rilled, 1 got a small sample weighing one and a half quintin. It had a saltish taste, and on crystallization afforded proper Glauber salt, which weighed two-thirds of a quintin, and ten grains of kitchen-salt.
The grey and hair-like ravelings abovementioned were found to be of the same nature as Nos. 1 and 4, and in all probability are the self-same substances drawn out into fine threads, which, from the delicacy of their structure, are easily broken, and are carried about by the wind in various directions to considerable distances. Twenty grains of them were melted down by means of a moderate fire to a black glass *. So
* Professor Wilke, at Stockholm, procured a small sample of this hair-like substance from Iceland, and has given a dissertation upon the subject, similar to