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West.

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at

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Mean of (Morning

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.. Variation $40 141 08" Observations. Noon

at 1 42 Ditto 24 21 45 in Oct.

Evening
at
Ditto

Not obs.
Morning
at 8 32

Ditto

24 · 14 33 Ditto in Sept.

Voon

at 1 39 Ditto 24 23 17 West, Evening

at

6 19 Ditto 24 16 50 Morning

at 8 30 Ditto 24 14 13 Ditto in Aug. Noon at 1 39 Ditto 24 23 48 West.

Evening

at 6 57 Ditto 24 16 31 Morning

at 8 41 Ditto 24 13 29

at Ditto in July. Noon

1
42 Ditto

West.

24 23 44
Evening
at 6 58

Ditto

24 17 00
Morning
at 8 44 Ditto

24 13 10 Ditto in Jupe. Noon

at

Ditto
24 22 48

West,
Evening
at 6 52 Ditto

24 16 29
Morning

at
8 45 Ditto

24 13 12 Ditto in May.

Noon

at 1 44 Ditto 24 22 13 West. Evening

at 6 38 Ditto 24 16 14 Morning

at 8 45 Ditto 24 1253 Witto in April. Noon at l 48

Ditto

West.

24 23. 53
Evening
6 29

24 15 30
Morning

at 8 52 ..... Ditto 24 14 29 Ditto in March. Noon at 1 52 Hitto

24 23 08

West,
Evening

at 6 11 Ditto 24 15 33
Morning
at 8 47 Ditto 24 14 50

West. Ditto in Feb. Noon at 1 52 Ditto 24 20 58

Evening
at
Ditto

Not obs.
Morning
at 8 52 Ditto 24 15 05

West. Ditto in Jan.

Noon

at 1 53 Ditto 24 19 03
Evening
at
Ditto

Not obs.
1813. Morning
at 8 53 Ditto

24 17 39

West. Ditto in Dec. Noon at 1 51 Ditto 24 20 30

Evening
at
Ditto

Not obs.
Morning at 8 40 Ditto 24 17 17

West. Ditto in Nov. Noon at 1 54 Ditto 24 20 24 )

Evening
at
Ditto

Not obs.
Morning at 8 45 Ditto 24 15 41
Ditto in Oct. Noon at 1 59 Ditto 24 22 53 )
Evening at

Ditto

Not obs, Morning at 8 53 Ditto 24 15 46 Ditto in Sept. Noon at 2 02 Ditto 24 82 32 West.

Evening

at 6 03 Ditto 24 16 04

Morning at 8 44 Ditto 24 15 55 Ditto in Aug. Noon

at

2 02 Ditto 24 23 32 West. Evening at 05

Ditto

24 16 08 Mornil

at 8 37 Ditto 24 1432 Ditto in July. Noon at 1 50 Ditto 24 23 04 West.

Evening

at 7 08 Ditto 24 16 43
Morning
at 8 30

Ditto

24 12 55 Ditto in June. Noon at 1 33 Ditto

24 22 17 West. Evening at 7.04.,i... Ditto

24 16 04 Morning

8 32

Ditto 24 12 02 Ditto in May. Noon

at
1 37 Ditto

24 20 54

West.
Evening

at 6 26. Ditto. 24 13 47
Morning
at 8 31

Ditto 24 09 18

at Ditto in April. Noon

( 59 Ditto 24 21 12 West, Evening

at 5 46 Ditto 24 15 25

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Magnetical Observations continued.

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Fest,

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Fest

Jan,

1 8h 50' 24° 17' 01! 1h 35' 24° 20' 04" Ditto 2 8 50 24 17 50 Ditto 3 8 50 24 17 24, 1 35 24 19 46 Ditto 48 50 24 19 20 1 55 24 20 32 Ditto 5 8 50 24 18 00 1 35 24 20 50 Ditto 6 8 45 24 17 02 Ditto 7 8 40 24 15 48 1 40.24 19 19 Ditto 8 8. 45 24 16 53 1 40 24 20 43 Ditto 9 8 40 24 16 50 1 35 124 19 23 Ditto 10 8 40 24 16, 35 1 45 24 17 46 Ditto 11 8 45 24 14 22 1 35 12+ 19 00 Ditto 12 8 45 24 15 58 Ditto 13 8 50 24 17 04 1 35 24 19 30 Ditto 14 8 45 24 18 08 1 20 24 20 37 Ditto 15 8 45 24 16 30 25 124 18 26 Ditto 16 8 40 24

17 02 35 24 19 41 Ditto 17 8 45 24 16 42 1

50 124 20 01

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Comparison of the Variations in the Years 1813 and 1814.

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April

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May

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24° 09' 18" 240 12' 53" 24 21 2017 24 23 53 24 15 25 24 15 30 24 12 02 24 1249 24 20 54 24 23 13 24 13 47 24 16 14 24 12 35 24 13 10 24 22 17 24 22 48 24 16 04 24 16 18 24 14 32 24 13 29 24 23 04 24 23 44 24 16 43 24 17.00 24 15 55 24 14 13 24 23 32 24 23 48 24 16 08 24 16 31 24 15 46 24 '14 33 24 22 32 24 23 17 24 16 04

16 50 24 15 41 24 14 08 24 22 53

24 21 45

Morning
Noon.
Evening.
Morning
Noon'.

Fvening.

(Morning June Noon..

Evening.

Morning
July Noon

Evening.
Morning
Noon.
Evening.
Morning
Noon.
Evening.

Morning
Oct. Noon ..

Evening.

Morning
Nov. Noon

Evening
(Morning
Noon
Evening.

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Dec. 19.--In taking the mean of the observations for the month

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of December, the variation on the 19th is rejected, on account of its being unusually great.

Jan 10, 1815.-The needles vibrated between three and four minutes ; and in the night the wind blew very hard, with rain, from the west.

Jan. 11.-At the morning observation the needles vibrated three and four minutes. The wind still blew very hard, and continued during the day. At noon the vibration of the needles was seven minutes.

Between noon of the 1st Dec.
Rain fallen Between noon of the 1st Jan. 2.590 inches.

1

Red le

.

ARTICLE XII.
ANALYSES OF Books.

THE
Memoirs of the Wernerian Natural History Society, Vol. II.
Part I. For the Years 1811, 1812, 1813. Edinburgh, 1814.

, The Wernerian Natural History Society was founded in Edinburgh, in 1808, for the purpose of cultivating all the different branches of natural history; though, from the name given to its i we are led to suppose that geognosy occupied the chief place, at least in the opinion of the original founders; as that name is derived from Werner, the celebrated founder of that important science. We had no opportunity of noticing the first volume of Memoirs published by this Society, as it made its appearance before the commencement of the Annals of Philosophy. The present the volume contains 20 papers, which we shall notice in their order,

1. Outlines of the Mineralogy of the Ochit Hills. By Charles Mackenzie, Esg.-This paper having been already published in the Annals of Philosophy, vo]. iii. p. 116, we shall satisfy ourselves with a very short account of it here. The Ochils are a beautiful chain of hills, lying chiefly in Perthshire in Scotland, uti and dividing Strathern from the river district of the Forth. These mountains are all clothed with verdure, and many of them cultivated to the very top; hence the rocks of which they consist are seldom exposed, and the task of ascertaining their structure is attended with almost insurmountable difficulties. It is not surprising, therefore, that Mr. Mackenzie was unable to determine exactly the relative position of the different rocks, and consequently the class of formations to which they belong. For my own part, I consider the Ochils as very like the Pentlands in their structure, and think that both consist of a series of rocks, not exactly similar to any that Werner has described as constituting either the floetz or the floetz trap; though, the lowest beds excepted, they seem more connected with the latter than the former. I suspect that a

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careful study of these two chains of mountains will occasion some
alterations in the present Wernerian arrangement of floetz trap
rocks. The rocks of which the Ochils are composed are the fol-
lowing :-

1. Red sand-stone.
2. Amygdaloid.-Basis clay-stone.
3. Grey sand-stone.
4. Lime-stone.-

Very uncommon.
5. Slate-clay.--Also in small quantity.
6. Clay-stone.-Abundant.
7. Tuff.
8. Basaltic clink-stone. -Peculiar to the Ochils.

9. Green-stone.
10. Clay-stone porphyry.--Common.
11, Felspar porphyry.

12. Compact felspar.-Common.
The veins which occur in these mountains contain calcareous
spar, steatite, sulphate of barytes, iron, cobalt, silver, copper,
lead.

Were those geologists, who consider all green-stone, basalt, and porphyry slate, as lava emitted from volcanoes, to examine the structure and relations of the Pentlands and Ochils, it would probably induce them to modify their opinions.

2. A Geological Account of the Southern District of Stirlingshire

, commonly called the Čampsie Hills; with a few Remarks relative to the two prevailing Theories as to Geology, and some Examples given illustrative of these Remarks. By LieutenantColonel Imrie, F.R.S. Edin. — This district constitutes a part of the very extensive independent coal formation, which occupies so great a portion of the southern part of Scotland, extending from the German Sea at St. Andrews to the western parts of Airshire. The district described by Col. Imrie consists of ranges of hills running north and south, and separated by narrow valleys. He found that these hills are composed of beds which have the following position, beginning with the lowest bed.

1. Shale.
2. Dark bluish grey limestone with entrochi.
3. Slate-clay.
4. Sand-stone.
5. Slate-clay mixed with glance coal,
6.-Dark bluish grey lime-stone,
7. Slate-clay.
8. Sand-stone.
9. Slate-clay.
10. Sand-stone.

11. A very thick bed of green-stone.
All these beds evidently belong to the independent coal forma-
kon, except the uppermost bed of green-stone, which from ita

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position, and its being confined to the top of the hills, probably belongs to the newest floetz trap.

Col. Imrie accounts for this disappearance of the green-stone, by currents of water which formerly flowed over this district from east to west ; and he points out traces of these currents, in scratches still remaining on the surface of the green-stone, and in the partis cular configuration of the hills. This is the ingenious speculation of Sir James Hall, to which he has given plausibility by his usual industry and address. But it is a very hazardous speculation, the sources of mistake being almost innumerable, and the means of correcting error very scanty. The speculation seems to have originated with Saussure and Dolomieu, who, however, were never able to make much of it.

Col. Imrie has entered into some discussions respecting the igneous or aqueous origin of green-stone. He has shown, by an example from the neighbourhood of Carthage, that columns may be formed in substances deposited from water; and by an example from the Lipari Islands, that they may be formed likewise from lava. Obsidian and pumice he considers as of volcanic origin. I should like much to know, whether the composition of the obsidian found in Hungary be the same with that found in Iceland, Lipari, and the Peak of Teneriffe. It is very likely that they would be found to differ; and that the dispute about the aqueous or igneous origin of this mineral, has originated from giving the same name to two different species.

3. Chemical Analysis of a Specimen of Magnetic Iron Ore from Greenland. By Thomas Thomson, M. D. F.R.S. L. and E.-The analysis of the ores of iron constitutes one of the most difficult parts of mineralogical chemistry. The present example, compared with the Swedish ores lately analyzed by Berzelius, is sufficient to show, that more than one species of magnetic iron ore exists. Berzelius's ores were combinations of black and red oxides of iron. My ore contained titanium, and from the quantity of red oxide of iron obtained, (126.5 from 100 of the ore,) it is obvious

of the iron must have been in the metallic state. This is further confirmed by the effervescence of the ore with muriatic acid. The speculation, that the ore consists of an unknown protoxide of iron, is supported by too slight analogies to be admitted.

4. Description of a Sword Fish found in the Frith of Forth, in June, 1811. By William Elford Leach, Esq. F.L.S. W.S. &c.

- To this species, Dr. Leach gives the name of Xiphias Rondeletii, because he thinks it was first discovered and described by Rondeletius. The Xiphias Gladius is likewise probably found in

. the Frith.

5. Some Observations on the Genus Squalus of Linnæus, with Descriptions and outline Figures of two British Species. By William Elford Leach, Esq. F.L.S. W.S. &c.—Dr. Leach divides the fạmily of the squalinidæ into four genera, as follows :

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