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3. a. Mean temperature in the mornings and evenings.

6. The same during the summer, or from May till October.

c. The same during the winter, or from November till April. 4. a. Mean temperature at two o'clock after mid-day.

b. The same during the six summer months c. The same during the six winter months..

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In general, January was the coldest, and Jaly the hottest month.

The first frost was always between the 8th of Sept. and the 9th of Oct.; but in general about the 27th of Sept.; and the last frost always between the 1st of April and the 12th of May, but mostly in April.

Each year had about 112 complete winter days, 59 harvest and spring days, with frost in the night, and 194 summer days.

The ice in the Neva River at St. Petersburgh was broken up sometimes on the 22d of March, generally on the 1st of April, and never after the 31st of this month. This river was never frozen again before the 16th of October, mostly on the 14th of November, and never later than the 12th of December. The river was navigable generally 218 days, and covered with ice 147 days.

Each year had, for the most part, 69 perfectly calm days, 166 days of strong wind, 103 windy, and 27 very stormy days. The west wind prevailed the most, and the south wind the least. Jannary was the most stormy, and had westerly winds, and July was the calmest month. The north wind reigned in April, the east in July, the south in November, and the rest in August.

Each year nad 91 fair days, 118 completely dull, 156 partly cloudy days, 106 rainy, 73 showery, 43 foggy, and 4 times hail; 13 to 14 times thunder, and 21 northern lights. In the year 1786, it thundered 18 times; in 1790 only 6 times : these are the extremes in 20 years.

The year 1774 had the most thunder and northern lights, the thunder having been heard 17 times, and the northern lights seen 48 times. It is remarkable that the northern lights have decreased since 1782, as from that year to 1786, they were seen 110 times, and only 39 times from 1787 to 1791,

The most serene months were April and June, next to them March, May, and July; November, December, and January, were the dullest months ; August was the most cloudy and variable, and next to it, the months July, May, and September. The greatest fogs are in February, and the most rain in July, August, and September; the most snow falls in December. It hails the most in May; in September, somewhat less, but never

in January and February; in December, only twice in 20 years ; in March and November, four times; and in June, five times.

The northern lights abounded in September and March, and July had the most thunder ; the former having been seen four times each month, and the latter heard four or five times. During 20 years, it thundered three times in June and August; June and July had no northern lights, and December, January, and September, had no thunder. In November, it thundered only once; in April it occurred five times, in October three, and in November, two thunder storms.

Statement of the Weather for the Years 1818 and 1819.

Barometrical Observations.

1818.

1819.

Eng: in. Eng. in. 1. a. The greatest height was in 1818 on Oct. 5, and in 1819 on Feb. 25...

30-88 31.32 The least height on Jan. 4, in 1818; and on Nov. 26, in 1819

28.28 28.86 b. The difference

2.60 2:46 The mean height..

29.58 30.09 c. The mean height from three observations every day in the year 30:17 30-09

Days. d. The mercury stood higher than 29.86 English inches during ... 253

Days. 281

Thermometer.

1818. 1819.

1. d. Greatest cold by Fahrenheit

The greatest cold in 1818 was on Feb. 17, and in 1819, on Dec.

17, below zero.....,

34

3. Greziehen on July 9, and on May 27, in the respective years

: 18:00 $

100 66 124

Days. Days. 2. a. There were days in which the temperature was below the freezing point in the mornings and evenings

150 174 b. In the above days, there were, in which the temperature was 300 below zero..

12 300 to 180 below zero

3 180 to 6 ditto.....

4 9 60 below to go above zero.

6 35 80 to 200 ditto....

20 41 200 to 320 ditto. .

112 84

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1818. 1819,

Days. Days. 3. a. There were days in which the temperature rose higher than the freezing point in the warmest part of the day...

273 229 b. Of these days, there were, in which the temperature was 800. 15 15 Between 80° and 670

38 46 67o and 550

64 68 55° and 430

63 48 93 52

43° and 32°.......

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4. a. The mean temperature in the mornings and evenings from the 1st of November to the 1st of the same month each year..

200 24 b. And the mean temperature at mid-day.........

60 61 c. But the mean temperature, from observations three times a day, taken soon after mid-day, was..........................

45 39 The same for the mornings and evenings...

37 27 d. General mean temperature, from three observations each day... 40 35 5. a. Last frost in the first part of the year was on May 18, 1918, and

April 28, 1819.
First frost in the latter part of the year was on Sept. 13, 1818, and
Oct. 15, 1819.

Days. Days 8. Wind blew ; very stormy or hurricanes.

14 17 Very windy....

25 76 Windy.

60

.......

218 Moderately windy.

251 Calm...

15 54 c. North wind prevailed

27 East.

51 South.

34 West

124 North-east.

36 South-east

24 South-west.....

32 North-west....:

22 d. Perfectly clear days ..

72 Partly clear and partly cloudy..

153 Overcast

140 e. There were in the above, misty days.

218 6. a. Rain fell during...

88 68

77 89 Hail, times

27 6 b. First snow was on Oct. 14, 1818, and Oct. 17, 181

Last snow was on May 5, 1818, and May 10, 1819. c. The water continued frozen

259 228 The summer had....

118 169

.........

Snow..........

Eng. Eng.

inches. inches. d. The rain, hail, and snow, were equal to a column of water of.... 12.84 16.96 The proportion of water yielded, from rain to that from snow, was

5 to 24 to 3

as. ....

Times. Times,

12 16

7. a. Thunder was heard ....

First thunder occurred on April 85, 1818, and April 6, 1819.
Last thunder was on the Sept. 1, 1812 and Sept. 18, 1819.

1818. | 1819.

Times. Times. b. Rainbows were seen

7 Circular round the sun occurred

7 9 Circular round the moon

5 13 Northern lights were seen

6 12 8. a. The river Neva was frozen on Nov. 15, 1819, and Oct. 27, 1819.

The ice was broken up on April 17, 1818, and April 9, 1819.

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On the Crystalline Form of Diaspore. By. W. Phillips, FLS. &c.

(To the Editor of the Annals of Philosophy.) In the Annals of Philosophy for the present month there is a communication on the subject of that rare mineral diaspore. In the cabinet of my friend, S. L. Kent, is another specimen considerably resembling that which is in the possession of G. B. Sowerby, but of a more highly crystalline structure.

The results obtained by subjecting the latter to the blowpipe by J. G. Children, Esq. tend to show that it does not differ essentially in character from the diaspore of Le Lievre ; and having been permitted to examine the specimen in the possession of S. L. Kent, which he bought many years ago at a sale of foreign minerals, without either a name or locality, I am satisfied that it also is a true diaspore.

I succeeded in detaching portions of several fragments of crystals, and one very minute and nearly perfect crystal, sufficiently brilliant for the use of the reflective goniometer.

This crystal is a doubly oblique prism, of which the form and measurements are shown in Pl. XIII. fig. 11. Mon T...

65° 0 P on M

108 30 P on T.

101 20 The plane o, though perfectly defined, is not brilliant enough for the use of the reflective goniometer, nor are three extremely minute planes in connexion with it at the lower solid angle of the prism.

I possess a very small fragment of Le Lievre's diaspore, on which the plane P of the preceding figure is very bright, and on which there is a cleavage parallel to the plane M, and hence I have been enabled to procure the measurement by the reflective

New Series, vol. IV,

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goniometer of 61° 40', which is so near to the complement of P on M (108° 30') that it is impossible to doubt its being P on M return over the edge X. Nor can a reasonable doubt exist that the two specimens are identical, though differing somewhat in appearance. They afford similar results on the application of heat.

W, PHILLIPS.

ARTICLE V.

On the Differences in the Annual Statements of the Quantity of

Rain falling in adjacent Places. By H. Boase, Esq. Treasurer of the Royal Cornwall Geological Society.

(To the Editor of the Annals of Philosophy.) SIR,

Geological Society, Penzance, June 1, 1822. Your intelligent correspondent Mr. Hanson, noticed (Annals for May, p. 372), that “the differences in the annual statements of rain from places near together are singular, and certainly require an attentive inquiry. The tables published from time to time, and periodically, in the Annals of Philosophy, exhibit still greater “differences” than those stated by Mr. Hanson ; and it was in consequence of remarking such anomalies that the resident officers of the Cornwall Geological Society instituted, above 12 months ago, a course of careful observations, with a view to an explanation of this phenomenon.

Suspecting that a part, if not a great part, of the differences arose from the disparity of gauges

or measures, our first care was to be accurate in that respect. Fig. 8 (Plate XIII), will show better than a mere verbal description, the form of the instruments we adopted. The upper rim, a, is of copper, one inch wide; the basin or funnel, b, is of pewter, two inches deep; the outer neck or cylinder, ç, is of the same material, as is also the pipe, d. This cylinder should so fit the neck of the bottle or receiver, e, as to keep the funnel quite steady ; and the pipe has a very small orifice at its lower end, and is covered by a perforated lid at top, in order to prevent, as much as possible, evaporation. The diameter of the copper rim is exactly six inches, and correctly turned in a lathe and perfectly circular. All this any expert brazier can accurately execute, and for the cost of 4s. or 5s. A common bottle does well for the receiver, but it should be of the capacity of not less than three pints wine measure, for a gauge of six inches diameter.

No less care is requisite in having a measure accurately graduated. A cylindrical glass jar or gas receiver, f, is very convenient, and easily obtained. In a guage of six inches diameter

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