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"1. That the relative weights of the constituent principles of different eggs vary very considerably.

“2. That an egg loses about one-sixth of its weight during incubation, a quantity amounting to eight times as much as it loses in the same time under ordinary circumstances.

53. That in the earlier stages of incubation, an interchange of principles takes place between the yelk and a portion of the albumen; that this interchange is confined on the part of the yelk to a little of its oily matter, which is found mixed with the above-mentioned albumen; that this portion of albumen undergoes some remarkable changes, and is converted into a substance analogous in its appearance, as well as in some of its properties, to the curd of milk; and lastly, that a portion of the watery and saline portion of the albumen is found mixed with the yelk, which becomes thus apparently increased in size.

“4. That as irrcubation proceeds, the saline' and watery parts again quit the yelk, which is thus reduced to its original bulk; that in the last week of the process, it undergoes still further diminution in weight, and loses the greater portion of its phosphoras, which is found in the animal converted into phosphoric acid, and in union with lime, constituting its bony skeleton ; and lastly, that this lime does not originally exist in the recent egg, but is derived from some unknown source during the process of incubation." *****Dr. Prout concludes this valuable communication with some remarks on the uses of the yelk, and the apparent generation of earthy matter. The opinion that the yelk is analogous to the milk of viviparous animals, but more concentrated, and that its chief use is to afford a pabulum to the young animal during incubation,” is, he says, “ corroborated in a striking manner by the present inquiry:"?, ale

DONA 9:14 With respect to the earthy matter found in the skeleton of the chick when it quits the shell, continues Dr. P. “I think I

” can venture to assert, after the most patient and attentive investigation, that it does not pre-exist in the recent egg : certainly not, at least, in any known state. The only possible sources, therefore, whence it can be derived, are from

the shell, or trapsmutation from other principles. Whether it be actually derived from the shell, cannot be determined by chemistry; because, as we have seen, the shells of different eggs differ so much, that the application of averages is out of the question; and we are of course precluded from ascertaining the exact quantity of lime any particular, shell, originally contains. There are, however, very strong reasons for believing, that the earthy matter is not derived from the shell. In the first place, the membrana putaminis never becomes vascular, and seems analogous to the epidermis ; hence the lime of the shell, which is exterior to this membrane, is generally considered by physiologists as extra

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vascular : * it is, therefore, extremely difficult to conceive how the earth in question can be introduced into the economy of the chick from this source, particularly during the last week of incubation, when a very large portion of the membranes are actually separated from the shell. Secondly, both the albumen and yelk contain, at the end of incubation, a considerable proportion of earthy matter (the yelk apparently more than it did originally); why is this not appropriated in preference to that existing in the shell? In opposition to these arguments, it will be doubtless stated, that the shell of the egg becomes brittle at the end of incubation, and appears to undergo, during that process, some other changes not at present understood. To which it

may be answered, that this brittleness has been attributed to the separation of the membrana putaminis, and the exsiccation of the parts by so long an exposure to the heat necessary to the process of incubation, and in this manner all the known changes produced in the shell by incubation may, perhaps, be satisfactorily accounted for. Until, therefore, it be demonstrated that some other changes take place in the shell, I confess this argument does not seem to me to have much weight. I by, no means wish, however, to be understood to assert, that the earth iş not derived from the shell ; because, in this case, the only alternative left me is to assert, that it is formed by transmutation from other matter; an assertion, which I confess myself not bold enough to make in the present state of our knowledge, however strongly I may be inclined to believe that, within certain limits,

I this power is to be ranked among the capabilities of the vital energies."

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Dr. Prout has requested me to insert the following correction of a passage in his paper :-In the twenty-second page of the paper itself, or p. 398 of the Philosophical Transactions, line 6 from the bottom, for “ after incubation," read after it had left the egg."-Edit.

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" See an essay on the Connexion between the Vascular and Extra-vascular Parts of Animals,' by Sir A. Carlisle.(Thomson's Annals, vol. vi. p. 174).” HIHI

28

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ARTICLE III.

Summary of a Meteorological Table kept at Bushey Heath during

1822. By Col. Beaufoy, FRS.

Mean 1822. Barom. Ther. Hygr. Rain. Evap. N NEE SE SSW WNW

temp.

W

1

Inches. Jan... 29.614 Feb. 29.612 March. 29.561 April.. 29.454 May.. 29.523 June..29.636 July .. 29.391 August 29.445 Sept... 29.503 Oct... 29.197 Nov... 29.17) Dec... 29.572

87.0 41.5 45.6 46:3 56.6 64.3 62.0 62.4 55.3 51:0 45.4 92.0

Inches. Inches. 7100 420 1•702 38.5 72.0 1.080 2:118 42.6 69.0 | 0.715 3.78046.6 64.0 2.482) 3.23047.2 59.0 1.666 4.240 57.2 56.0 0.780 6.520 65.3 59.0 2.504

62.4 62:01.654 4.860 61.3 64.0 1.0601 3•76056:1 73.0 3.479) 1.930 51.4 78.0 3.097 1.550 46:3 71.0 1.400 1.000 33.2

12101 07 8 10

2 16 1 1 3

18. 7] 0/10

0 8 이 6.
0/14

이 51 2.
11 5/ 2 1 04
01 2 04 2 13 5 5
이 3 2 1 136) 5
0 14

6 41
0 3 212 13 ol
01 4 이 4 0 21 | 0
0/12 4 4 10 6 4

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Greatest height of the thermometer during the year was 851°, June the 10th ; least height, 184°, December the 30th.

This table is similar to the one published in the Annals of Philosophy, Feb. 1822.

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ARTICLE IV.

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Astronomical Observations, 1822, 1823,

By Col. Beaufoy, FRS.

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Bushey Heath, near Stanmore.
Latitude 51° 37' 44•3" North, Longitude West in time l' 20.93".

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Dec. 21. Emersion of Jupiter's thirds 7h Aş' 58" Mean Time at Bushey. satellite ...

{ 7 45 19 Mean Time at Greenwich. Dec, 25. Emersion of Jupiter's first 9 28 49 Mean Time at Bushey, satellite...

9 30 10 Mean Time at Greenwich. Dec. 28. Egress of Jupiter's third sa S 8 26 28 Mean Time at Bushey. tellite..

8 27 49 Mean Time at Greenwich, Dec. 28. Emersion of Jupiter's third Il 45 47 Mean Time at Bushey: satellite ..

11 47 08 Mean Time at Greenwich. Dec. 29. Emersion of Jupiter's second 9 36 20 Mean Time at Bushey. satellite.

9 37 41 Mean Time at Greenwich. Jan. 8. Emersion of Jupiter's first § 13 19 53 Mean Time at Bushey, satellite

? 13 21 14 Mean Timc at Greenwich,

ARTICLE V.

during

An Account of the Process of smelting Copper as conducted at the

Hafod Copper Works, near Swansea. By John Henry Vivian,
Esq. FRS. MGS.

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[Haying lately been consulted by Messrs. Vivian and Sons,.' proprietors of the Hafod Copper Works, as to the means by which the inconvenience arising from the smoke of the copper works might be remedied, the following account, forming a part of Messrs. Vivian's statement, appeared to me to possess much general interest: I, therefore, requested, and readily obtained, permission to publish it.- Edit.]

The copper ores smelted in the works in South Wales are for the most part raised in the mines of Cornwall and Devon.' They consist chiefly of yellow copper ore or copper pyrites, and the grey sulphuret of copper. The yellow ore is a compound of sulphur, iron, and copper, in nearly

equal proportions. The grey ore, at least what is known in Cornwall under that denomination, is almost a pure sulphuret of copper containing about 80 per cent. of metal Yellow ore, which is by far the most abundant, is usually accompanied by iron pyrites, or sulphuret of iron. The earthy minerals that occur with these metallic substances are chiefly silicequs, although in some mines the veins are of an argillaceous or clayey nature, while in others they contain fluor spar, or fluate of lime. Thus the component parts of the Cornish copper ores, as prepared for smelting, may be said to be sulphur, copper, iron, and from 60 to 70 per cent, of earthy matter. To these may be added, as accidental, tin and arsenic; for although these substances are not chemically combined with the copper, still as the ores of tin and copper frequently occur in the same vein, it is impossible to effect their complete separation by mechanical means. The quantity, however, compared with the substances above enumerated, is inconsiderable ; for as the miner is not paid for the tin when contained in copper ores, it is of course his interest to separate it as clean as possible. The arsenic is derived from the arsenical pyrites which usually accompanies tin ores. The average produce in copper may be stated at 8.1 per cent.

The ores are conveyed from Cornwall to Wales to be smelted on account of the supply of fuel, as not only carrying the smaller quantity to the greater, the ore to the coal, but because the vessels load back coal for the use of the engines of the mines. The principal smelting works are situated on the navigable rivers of

New Series, Vol. V.

I

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Swansea and Neath. The processes in a copper work are simple: they consist of alternate calcinations and fusions. By the former the volatile matter is expelled, and the metals previously combined with the copper oxidized, the general fusibility of the mass being thereby increased. The calcination is in fact a preparatory process to the fusion, in which the metallic oxides and earthy matters, being rendered specifically lighter than the metals, float on the surface, and are

skimmed off as slags. The furnaces in which these operations are performed are reverberatory, and of the usual construction. The substance to be acted on is placed on the body of the furnace or hearth, which is separated from the fire place by a bridge of bricks about two feet in thickness. The flame passes over this bridge, and, rever berating along the roof of the furnace, produces the required temperature, and escapes with any volatile matter that may be disengaged from the ore or metallic sulphurets through a flue at the opposite extremity of the furnace, which flue communicates with a perpendicular stack or chimney.

These furnaces are of two descriptions, varying in their dimensions and internal form. The calcining furnaces, or calciners, are furnished with four doors or openings, two on each side the furnace, for the convenience of stirring the ore, and drawing it out of the furnace when calcined. They vary in their dimensions but are commonly from 17 to 19 feet in length from the bridge to the flue, and from 14 to 16 in width; the fire-place from 4 to 5 feet across by 3 feet.

The melting furnaces are much smaller than the calciners, not exceeding 11 or 11, feet in length by 7 or 8 feet in the broadest part: the fire-place is larger in proportion to the body of the furnace than in the calciner, being usually from 3.4 to 4 feet across, and 3 or 34 feet wide, as a high temperature is required to bring the substances with as little delay as possible into fusion. These furnaces have only one door, which is in the front part of the furnace. The accompanying sketches may convey some idea of the construction of these furnaces ; fig. 1 being a plan of a calciner; fig. 2 of a melting furnace.

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