out, runs upon those bodies, and is collected in a sort of regular tubes, which give it the name of manna in cannoli, that is, manna in tubes: this second kind is more esteemed, and always preferred to the other, because it is free and clear. There is indeed a third kind of manna, which is not commonly to be met with; it is very white, like sugar; but it is rather for curiosity than use. The two sorts of manna above-mentioned undergo no kind of preparation whatever, before they are exported; sometimes they are finer, particularly the manna grassa, and sometimes very dirty and full of impurities; but the Neapolitans have no interest in adulterating the manna, because they always have a great deal more than what they generally export; and if manna is kept in the magazines, it receives often very great hurt by the southern winds, so common in this part of the world. The changes of the weather produce a sudden alteration in the time that the manna is to be gathered; and therefore when the summer is rainy, the manna is always very scarce and very bad.

After this short account of the manna, I shall, says Dr. C. give you a little of the history of the Tarantula, because I have had an opportunity of examining the effects of this animal, in the province of Taranto, where it is found in great abundance: but I am afraid I shall have nothing more to say, than that the surprizing cure of the bite of the Tarantula, by music, has not the least truth in it; and that it is only an invention of the people, who want to get a little money, by dancing when they say the tarantism begins. Probably sometimes the heat of the climate contributes very much to warm their imagination, and to throw them into a delirium, which may be in some measure cured by music: but several experiments have been tried with the Tarantula; and neither men nor animals, after the bite, have had any other complaint, but a very trifling inflammation on the part, like those produced by the bite of a scorpion, which go off by themselves without any danger at all. In Sicily, where the summer is still warmer than in any part of the kingdom of Naples, the Tarantula is never dangerous, and music is never employed for the cure of the pretended tarantism. Every year this surprizing disorder loses ground, and doubtless in a very little while it will entirely lose its credit.

XXIII. Observations made at Dinapoor, on the Planet Venus, when passing over the Sun's Disk, June 4, 1769, with three different Quadrants, and a Two-Foot reflecting Telescope. By Luis Degloss, Captain of Engineers, with the Assistance of J. Lang and A. Stoker. p. 239.

At Sun-rise cloudy

the's

At 5 20 32 A. M......The sun disengaged from the clouds, when Venus appeared on the O's disk. At 7 5 22.

At 7 23 36.

The beginning of the emersion.

The end of the emersion.

The latitude of the place where the observation was made, is 25° 27′ N.

The time is exactly corrected, and all the allowances made.

XXIV. Directions for making a Machine for finding the Roots of Equations Universally, with the Manner of Using it. By the Rev. Mr. Rowning. p. 240. Perusing a discourse in the memoirs of the Royal Academy at Petersburg, tome 7, page 211, by the learned John Andrew de Segner, containing a universal method of discovering the roots of equations, Mr. R. found, that the author's method consisted in finding several ordinates of a parabolic curve, such, that its abscissas being taken equal to any assumed values of the unknown quantity in the equation, the ordinates corresponding to those abscissas, should be equal to the values of all the terms in the equation, when brought to one side; that is, in other words, in finding several ordinates of a parabolic curve defined by the equation proposed: in which case, as is well known, if a curve be drawn through the extremities of the said ordinates, the points on the axis, where the curve shall cut it, will necessarily give the several values of the real roots of the equation; and the several points, where the curve shall approach the base, but shall return without reaching it, will show the impossible ones.

This is a method Mr. R. himself fell upon 10 or 12 years before, and had constantly used for finding the roots of such equations as he had had occasion to consider. But Mr. S.'s method is preferable in one respect, viz. that whereas Mr. R. always computed the value of the ordinates in numbers, Mr. S. finds them by drawing certain right lines; however, when there are both possible and impossible roots in an equation, as generally there are, these methods are both of them extremely embarrassing: the learned author therefore wishes, that some method might be thought of, whereby such curves, as now spoken of, might in all cases be described by local motion; but this, he tells us, he looked upon as so very difficult a task, that he never attempted it. This hint, however, convinced Mr. R. that the thing was possible; he therefore determined to endeayour to discover it.

He soon found, that if rulers were properly centred, and so combined together, that they should always continue representatives of the several right lines, by which he discovers the above-mentioned ordinates, on moving the first, a point or pencil, so fixed as to be carried along perpetually by the intersection of the first and last rulers, would describe the required curve, let the number of dimensions in the equation be what it will; only the greater that number, the greater must be the number of the rulers made use of. And this appeared to Mr. R. so obvious, that he wondered that neither the learned author, who seems to have the thing much at heart, nor any body else since its publication saw it.

But as this is a matter of curiosity rather than any use, and as the method was afterwards published separately, in 1771, it is unnecessary to enter any further into it at this time.

XXIII.* On the late Transit of Venus. By Nathanael Pigott, Esq. Dated Caen, Lower Normandy, Feb. 9, 1770. p. 257.

To his own observations Mr. P. has added those of other observers, which were sent to him from different places, and reduced them to the observatory of Paris, keeping an account only of the difference of meridians, as inserted in the Connoissance de tems, and omitting the small correction of the parallax, suitable to the different situations of these places, because the longitude of some of them is not known with sufficient precision, to admit here of this very small equation.

Table of Observations reduced to the Meridian of the R. Observatory, at Paris.

The place at Kew, where Dr. Bevis observed, being 1m 9 to the west of the observatory at Greenwich, is of course 10m 25 west of that at Paris. The observations in the table, joined by a brace, were made together in the same place. In comparing the observations of the internal contact, it is seen how little the last five agree with the others. Mr. P. was wholly ignorant in what light the able astronomers, who observed at St. Hubert, consider their observations. M. le Monnier, in communicating them, adds no remarks on them. As to those made at the house called La Mission, situated in the neighbourhood of Allemagne, a village near this town; this house is about 500 toises south-east of Mr. P.'s observatory at Caen, and their difference of meridians about 200 toises. At 7h 4m 58.5 of the clock, or 7h 9m 38.5 apparent time, Mr. P. perceived the external contacts of the sun's and Venus's limbs. As the impression on the sun's limb seemed considerable, he concluded this observation too late, which he

judged to be occasioned by a motion of undulation, with which the sun was strongly affected; for this reason, he does not hesitate to declare this observation insufficient; yet it agrees very well with Dr. Bevis's made at Kew, and is nearly a mean between those of Greenwich, as may be seen by the table. However, Mr. P. prepared himself with all possible care, for the observation of the internal contacts; and though the sun's limb moved continually up and down with a quick motion, he judged the internal contacts at 7h 21m 445.5 by the clock, or 7h 26m 24.5 apparent time, and 3 or 4s later, he saw a thread of light separate the planet from the sun. Mr. P. perceived that Venus, before she separated from the sun, was considerably stretched out towards his limb, which gave the planet nearly the form of a pear; and even after the separation of the limbs, Venus was 12 or more seconds before she resumed her rotundity.

Clock.

75.0.. Venus quite round.
5.0.. Venus's limb indented.

Apparent time. At 7h 30m 27.0....7h 35m 7 38 25.0....7 43 7 45 8.0....7 49 48.0.. Venus of a very irregular form, and strongly affected by an odd twisting motion.

XXIV.* Observations on the proper Method of calculating the Values of Reversions depending on Survivorships. By Richard Price, D. D., F. R. S. p. 268. See Dr. Price's treatise on reversionary payments.

XXV. Of Electrical Atmospheres. By J. B. Beccaria, F. R. S. p. 277. For these theorems, see the author's treatise on electricity, published in English by Mr. Nourse in the Strand, in 1776.

XXVI. On the Preservation of dead Birds. By Mr. T. S. Kuckahn. p. 302.

Mr. K. thinks he has tried most, if not all, the methods that have been published or practised for many years past, with all the care and attention he could; and it was not till after the loss of much time and many fine subjects, birds in particular, that he set himself to find out such methods, drugs, and liquors, as would effectually penetrate and perfectly cure all the parts, so as to keep them plump and full. With regard to the present ways and materials, he first remarks on that in which raw alum, common salt, and black pepper, are applied, that he never could find those materials sufficient for a perfect preservation. They never fail to become humid in moist air and long continued wet weather; they suffer the flesh to rot, and even corrode the wires made use of to confine the birds in their natural attitudes, till the whole drops to pieces on the least touch or motion. Salt naturally degenerates to a pickle; if the bird has been killed by shot, it will ooze through the shot holes. If it has been killed by hand, an

incision must be made, in order to extract the entrails and put in the materials that are to effect the preservation. Now it is impossible to close that incision so tight, as to confine the pickle from creeping out, and whenever it does get out, it will infallibly spoil the plumage; or if, to prevent that, we hang up the birds by the feet, then the pickle will descend to the neck and head, before the upper parts in that situation are sufficiently cured; the certain consequence of which, (in summer here, and at all seasons in hot climates) will be, that maggots will be generated in such uncured parts, and of course the birds destroyed. Supposing however for a moment (what will scarcely be found to happen once in a thousand trials) that the pickle should penetrate and cure every part, we have then, what?-a bird preserved in its natural shape, dimensions, attitude, and colours. No, but we have a poor shrivelled up dried carcase of a bird, in which neither the natural shape, dimensions, nor colours, are preserved, and which continually excites the disagreeable idea of its having been starved to death on purpose. It is true the eyes look lively and in full preservation; and no wonder, for they are glass; they serve, however, by the contrast, to show more strikingly the miserable condition of the rest of the body. One would have imagined that so palpable an absurdity, as the placing a fine full glistening eye in the head of a body, not only manifestly dead, but appearing to have perished by sickness or famine, would have been obvious to every body; to have kindly suffered the languid eyelids to close, would have at least avoided so ridiculous a contradiction. Lastly, experience shows that birds thus treated are seldom or never so cured, but that the flesh grows rank; that rankness invites the insects, and of course the bird is soon destroyed.

A second method of preserving birds is, by immerging them in spirits; and if the barely keeping the carcase of birds from putrefaction be all that is required, this method is effectual. Another method is that of skinning birds; they had no other way in Germany and Holland, and it was generally practised in France till very lately, when the method of preserving by alum, salt, and pepper, was published and recommended. Skinning, compared with the other methods, is no bad way, but yet it is subject to many objections; 1st, there is a great difficulty in skinning, especially small delicate birds, killed perhaps by large shot; 2d, most people will find it hardly possible to reduce the skins to their natural proportions and attitudes, particularly the necks, which are often twice as long when separated from the vertebræ, as before; 3dly, the flesh and bones of the wings and rump must, after all, be left with the skin, and are as difficult to preserve as any other parts of the body. However, those who chuse to continue this method, will find their interest in making use of the materials recommended below.

Those who shoot birds for the purpose of preserving, should always be pro