equal to the distance of Vesuvius from Paris. The report seemed so well transmitted by the air, that it was mistaken for the discharge of artillery, and was the cause of several military movements in various parts of the American continent.

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ARTICLE XII.

An Account of certain Instruments formerly used for the Purpose of Blasting in the Lead Mines of Colonel and Mrs. Beaumont, at Allenheads. Communicated by Mr. Thomas Crawhall, of Newcastle-upon-Tyne.*

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THESE sketches represent an iron instrument found in Allenheads lead mines, supposed to have been formerly used in blasting, the length of which was 2 or 3 feet; the upper part having since been cut off, there only now remain 6 inches above the bended part, which is 1 inch square to the elbow, forming an angle of about 10°; is of a cylindrical shape, slightly tapering to the other end, which is one inch in diameter. On the butward side of the angle, along the circular part, is a groove'six inches in length, of one-quarter inch broad, and of similar depth, projected (it is supposed) to receive the train of gunpowder, perBadk dgsb sdt of

* From the Archæologia Eliana, vol. i.

taining to the charge: the application of which has been to drive it tightly into the hole bored in the rock above the powder, and the upper part fixed by strong timbers placed across the top for the purpose of preventing it being thrown out, without the desired effect.

Another instrument of iron, found in the same lead mines, differs from the above, in wanting the square bar at top, and in place of the hollow on one side, is cylindrical, and has a tube, one inch diameter, to nearly the upper end, where it is flattened, and has a shoulder projecting half an inch on each side, resembling the head of a spear, and apparently intended for fixing across it bars of iron or timbers, to oppose the violence of the ignited gunpowder.

At the round end of the cylinder is a perforation a, communicating through the hollow tube, with another at b, placed for a touch hole on one side, 1+ inch below the shoulder, and 8 inches distant from the other end.

.b

A tradition exists among the miners, that formerly strong timbers and wedges were used for fixing down the charges in blasting, to hinder explosion without effect; but no further explanation, as to the mode in which this was achieved, is to be obtained, neither in regard to the process of charging, nor of the tools used. It is highly probable, however, that such application might have been, and was adopted, for securing the two instruments above described.

A series of five more of these instruments have been found in the same mine, of the respective lengths of 84, 10, 104, and 12 inches.

There was also discovered, in opening some old workings at the west end of Allenheads lead mines, about a month since (Jan. 1820), a tool, formerly used, it is conjectured, for the purpose of blasting with gunpowder, or rather, in forming a cominunication with it in the rock to be exploded. The spot where it was found is in the Great Limestone there, about 40 feet from the surface. The latest record of this place having been wrought, was in the year 1716, since which period this part of it has been entirely filled up with rubbish and fallings in of the vein, and only recently re-opened; when the following (see next page), with some other instruments, were discovered in one of the flatts in the limestone. The oldest workmen of the present day do not recollect their use, nor did they ever hear of such tools employed for the purpose; they seem, however, to have been meant for it, and their application as follows:-After having drilled a hole in the rock to be blasted, with a chisel or jumper sufficiently deep, the gunpowder is put into the bottom of it, say to the depth of three or four inches; next the tool sketched

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which is round at one end, one inch in diameter, with a hole in the centre about one-eighth of an inch, which communicates with another of the same dimensions, about one and one-fourth inches from the other end on the cylindrical side, the opposite being flattened from within one inch of the bottom, or circular end, to one-third of an inch thick at the other extremity; this hollow cavity appears to have been filled with powder, which, when the instrument was placed in the hole, would immediately communicate with the charge. In this situation, it is presumed, wedges (of wood) were driven against the flat side of the iron tube, to resist the force of the gunpowder, so imp when fired through the touch-hole marked a,

by a train or match laid for that purpose. Howe
long this has been in disuse is altogether uncer-
tain, even the name is forgotten: it is probable
a century might since have passed away.

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Nearly in the same spot with the above, to which I annex a sketch, a tool of more recent user was found, called by the miners the stock and feathers; and remembered by some to have been occasionally used about fifty years ago, particularly inawet situations, where gunpowder could not, without great difficulty, be applied. A perforation was made in the stratum, say four to six inches deep; placing two thin pieces ofono. iron,s called the feathers; which are rounded one

one side and flat on the other, in this hole, the former being next to the rock, the wedge or stake was driven between until a portion of it split asunder.

This wedge also was found near the same place with the preceding, of six inches in length, and one and one-fourth inches square, tapering to a point, having a hole one-fourth inch square, through it, at one and a half inches from the top; this, according to the reports of very old miners, was intended to receive a small rod of iron, by which, one man held, whilst another drove the wedge; but not used during the life of any present workman.

At what period the present method of blasting was introduced into these mines cannot be ascertained. A person now residing there, recollects to have heard his father (who died thirty-nine years ago at the age of sixty-seven) say, although it took place before his time, that prior to the pricker and drive-all being used, it was so hazardous an experiment, that two men were specially appointed, whose province it was to visit the different workings, for the express purpose of charging and blasting, after the holes had been prepared. Another, who, as well as his father and grandfather before him, has been a pickman for sixty years past, has a faint remembrance of hearing very old men say, that formerly stemples were employed, but has no knowledge as to the process, nor ever saw any other mode prac tised than the present; but that the stock and feathers had been in use during both the lifetimes of his father and grandfather.

Inquiry how far the Opinions generally entertained of the Inuti lity of Observations of the Eclipses of Jupiter's Third und Fourth Satellites, are well or ill founded. By J. South, FRS.

(To the Editor of the Annals of Philosophy)

DEAR SIR, Blackman-street, Feb. 23, 1824. To the advancement of natural knowledge there is probably no one thing so inimical as prejudice, and perhaps there is no science, which has suffered so much from this common enemy to all, as has astronomy. To enumerate the various mischiefs which this busy fiend has inflicted upon this peculiar science would be foreign to the present purpose. Suffice it to say, its baneful effects have been not only felt by physical, but also by practical astronomy.

After the discovery of telescopes (as might be expected), we find them employed upon Jupiter and his satellites, more than upon any

other object. The phenomena of four moons were naturally interesting, nor was the inquiry unattended with important consequences. The velocity of light repaid the labours of Roemer, and the eclipses of the satellite's opened a new, easy, and at that time a comparative accurate mode of determining the differences of longitude of distant stations. Hence astronomers were taught to look out for these phenomena, and their observations became recorded: in proportion, therefore, as the opportunities of observing these eclipses were more or less frequent, were they supplied with means of improving their tables; till at length something like accuracy was arrived at, as far as relates to those of the first and second satellites; to this also we must add another cause which will be found in the nature of the instruments at this time employed; for the rapid motion of these two satellites is such, that the intervening period between their first entrance into the shadow, and their complete obscuration by it, is short; hence telescopes were able to give something like uniformity to the observations of various observers in short, theory and practice assisted each other.

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But not so with the outer satellites ; eclipses of them were comparatively of very rare occurrence, and the time of their entering the shadow till their complete obscuration being many times greater than in the case of the two first satellites, the observations became more difficult and the instruments were inadequate to the purposes for which they were now wanted: observations, therefore, of different observers differed considerably with each other, and theory and practice were everlastingly at variance. Hence observations of these satellites came into disrepute, and almost into disuse.

At length, however, in the preface to a work entitled "Tables Ecliptiques des Satellites de Jupiter," the monstrous discordancies between the existing observations of the eclipses of the third and fourth satellites were dwelt upon, with considerable energy, by the celebrated Delambra; and, perhaps, to the sentiments expressed by this great man, may we trace the principal cause why at the present moment, observations of the eclipses of these two satellites are almost generally neglected. When, however, prejudice seems distributed by one whose name, like that of Delambre, is never mentioned but with respect, does it become dangerous; and more and more imperative is it, upon the humblest labourer in science, to point out the errors, which it leads to this must plead my excuse for the present communi, cation.po 159 - vit um 12

As the work to which I allude, may not be in the library of every practical astronomer, I shall quote from it some of the passages calculated in my mind to prejudice observers.

Page 51. Having alluded to some trifling equation which might be applied as a correction to his tables of the third satel lité. He says, "Je n'ai poussé l'examen plus loin; mais il paraît en résulter que cette équation ne s'accorde pas plus avec