In a note to the above paper, M. Poggendorff states, that on the same day the needle also experienced great irregularities at Freiberg. On the 5th of May, at 7 o'clock 20 min. P.M. (8 h. 28′ of Petersburgh time,) the needle was 2'45" eastward; from this time it moved in an easterly direction, so as to have reached, at midnight, 21'9", when violent oscillations were observed, and the needle rapidly moved westward, so as to be at 12 h. 15' A.M. 16′ 14′′ west, and consequently 37′ 20′′ more westward than a quarter of an hour before: this was the maximum of the westerly deviation-at 12 h. 17' it had diminished to 12/0*.

22. DESCRIPTION OF SOME ATMOSPHERIC PHENOMENA.

(Professor Strehlke, of Danzig.) On the 29th of last March, 1830, I observed the phenomenon of coloured rings and parhelia, which, as I see from the papers, were at the same time also seen at other places. It appears, that for some time before and after the above date, the atmosphere was in a state peculiarly favourable to appearances of this kind, for, on the 20th of March, at 5 o'clock P.M., a large coloured areole had formed round the sun about 45° in diameter; the sky was covered with numerous parallel strata of clouds, which appeared to converge towards the sun, opposite to which they had another point of convergence. The colours of the ring were dull red internally, and bluish externally. On the 30th of March, at 10 o'clock P.M., a white halo of 45° had formed round the moon. On the 9th of April, at 6 o'clock P.M., the sun was surrounded by segments of an areole of 45° in diameter; on the 10th, at 11 o'clock A.M., it had an incomplete areole, from the uppermost portion of which a white circle subsequently formed, inclosing the zenith. But the most striking of all was the phenomenon observed on the 29th of March. On the 28th, the wind was northerly, and in the night it froze; on the 29th, the wind went through east to south. The following table exhibits the meteorological observations on these two days :

At 3 o'clock 45 min. on either side of the sun, and at the distance of about 22° from it, there were two parhelia, the outer part of which was white, the inner red; the horizon was rather cloudy, *Poggendorff Annalen der Physik und Chemie.

and the rest of the sky filled with nimbus. After a few minutes there appeared round the parhelia B and C (Fig. 1.), large segments of

the circle BDC B, the inner part of which was red; towards C the circle was thinner, and not so complete as on the south side B; and at the uppermost part, D, the arch was not completely closed at the same time a white sun was visible opposite to the real one at about 20° above the horizon. The clouds now gradually ascended towards the zenith, so as to leave but slight traces of the arch at B, and to efface C and the northern parhelion completely. The sunshine was very weak, and the clouds were of a brownish-red hue, when on a sudden the circle HER appeared at 45° from the sun; it was red internally, green in the middle, and blue outside. The northern arch was less distinct than the southern, EH; at E also the segment of a circle round the zenith was visible of about 45°, and there the most vivid colours were seen, from purple to green and violet. At 4 o'clock, H E B had nearly disappeared; the segment FE I was still visible, and remained so till half past four, when all traces of the phenomenon had disappeared, and the sky was equally covered with a cloudy surface.

Two of my friends, who happened to be at a distance from me of some thousand paces towards the south, saw, besides the two parhelia B and C, a third in D, and through it there was a segment of about 22° parallel to the horizon; it was of red colour at the side directed

towards the real sun, and afterwards changed into an undulating line; the other appearances were those described above.

On the 1st of December, 1828, at 2 o'clock 25 min. P.M., I observed the phenomenon of which a sketch is given in Fig. 2. The sun A was, at a distance of about 45°, surrounded by the arches H M and RN, the inner parts of which were red, and the outer blue; at 22° from the sun there was another ring, and at its uppermost part an arch K D T, both of a red colour at the side towards the sun; besides these appearances, there was a vertical and a horizontal column of yellowish light, and of the apparent diameter of the sun. At 3 o'clock 35 min., when it began to snow, the phenomenon disappeared.

During one of the nights in August, 1828, I saw, at midnight, very beautiful coloured halos round the moon, and as I happened to pass over fields, some of which were covered with fog, and the others clear, I was surprised to find that the halos ceased to be visible whenever I was on a field which was free from fog, but always reappeared when I came on a field covered with fog. There were three, and sometimes four halos, at small distances from each other, and with very vivid colours, red being always at the outer circumference; opposite to the moon there were segments of a white circle. The sky was clear, and the atmosphere tranquil *.

23. ON THE PRODUCE OF GOLD AND SILVER IN THE RUSSIAN EMPIRE. (Alexander von Humboldt.)

The yearly produce of the Russian gold and silver mines has lately been very variously stated; and as I am afraid that some of these statements may be attributed to me, I take an opportunity of giving the following numerical exposition of the fact.

According to official documents, the Russian mines yield annually about 22,000 marks of gold, and 77,000 of silver. In 1828 the produce of gold was 22,256 marks (318 puds, of which 115 were obtained from imperial, and 203 from private mines); of silver 76,498 marks (1093 puds); and of platina 6570 marks (94 puds); and the respective value was, of gold, 4,896,000 Russian dollars (700,000l. sterling); and of silver, 1,071,000 dollars (153,000l. sterling). The gold mines of the Ural yielded in—

In the first six months of 1829 they gave 142 puds of gold (46 from imperial, and 96 from private mines), and 43 puds of platina. The total produce of the Ural mines, from 1814 to 1828, is 1551 puds, of the value of about 3,413,000l. sterling; the last five years alone yielded 1247 puds.

* Poggendorff's Annalen.

The annual produce of gold in Europe and in Asiatic Russia amounts to 26,500 marks of gold, and 292,000 of silver, of which the Russian empire alone yields 22,200 marks of gold, and 76,500 of silver*.

24. ON THE CHANGE WHICH THE AIR IN EGGS UNDERGOES DURING INCUBATION.-(Professor Dulk, of Kænigsberg.) This philosopher has lately made some analyses of the air in the large end of the egg at different periods of incubation, and the following is the result of his inquiries.

Before incubation, the air contains considerably more oxygen than atmospheric air, the oxygen in the former being found, at two different experiments, 25.26 and 26.77; and that in the latter, on the day of the experiments, only about 21.0 †.

On the tenth day of incubation the air was found to contain 22.47 of oxygen, and 4.44 of carbonic acid; the absolute quantity of oxygen is accordingly nearly the same, but 4.44 of it has united with carbon. On the twentieth day, the quantity of air in the egg was found to be nearly eight times as large as before incubation; the analysis gave, at four different experiments,

where the absolute quantity is the same as in the former experiments, but the quantity of carbonic acid is increased; that of the third experiment, being only 6.19 per cent., corresponds, however, in some degree, with the result of the other analyses, as the chicken had apparently died a considerable time before the experiment was made.

* Poggendorff's Annalen, 1830. p. 273.

Though this result is somewhat at variance with that obtained by M. Bischoff, according to whom the mean quantity of oxygen before incubation is only 23.475, the experiments of both philosophers agree, inasmuch as both show that the air of fresh eggs contains more oxygen than atmospheric air.

From Schweigger-Seidel's Jahrb. der Chemie und Physik.