scribes and critically examines the orabanche major, elatior, minor, cœrulea, and ramosa; all growing in Great Britain.

Account of a minute Ichneumon; by Dr. George Shaw. This truly microscopical insect, the ichneumon punctum, seems to differ from the ichneumon atomas of Linné: but Dr. Shaw declines to decide the question, and contents himself with mark-. ing the difference and giving the description.

Description of the Phasma Dilatatum; by Mr. John Parkinson." -This curious insect is supposed to be a native of Asia.

Description of the Blight of Wheat, Uredo Frumenti; by A. B. Lambert, Esq.-Every minute circumstance which relates to the history and culture of wheat has a considerable degree of importance attached to it; and therefore this paper is deserving of attention.

Ammophila, a new Genus ef Insects in the Class Hymenoptera ; by the Rev. William Kirby.-The importance of the parts commonly called instrumenta cibaria, in order to discriminate the genera of insects, is generally allowed by all entomologists, since Fabricius built his system chiefly on them. Mr. Kirby, having dissected several insects of the class hymenoptera, found the tongue and its accompanying parts very different in the apis, the vespa, and the sphex; and in the sphex sabulosa, or sand wasp, very different from all the preceding. This observation led him to the institution of this new genus, of which he gives the natural and essential characters, together with the description of four distinct species. It appears to be very fairly distinguished from the apis by the bifid tongue, and by the antennæ filiform in every sex; from the vespa, by the direction of the rostrum, the form of the eyes, and the plane surface of the wings; from the sphex, by the direction and length of the rostrum, and the bifid tongue. This last characteristic, with the number of articulations, and form of the antennæ, prevent this insect from being confounded with the ichneumons

The Characters of twenty new Genera of Plants; by Dr. James Edward Smith.-Some years ago, Dr. Smith began to publish, periodically, the Botany of New Holland. The interruption of this design we cannot but lament; and it is to be hoped that he may yet resume the work. In the mean time, he here gives the characters of nineteen new genera from that distant country; together with the afzelia, a new genus from. tropical Africa.

Further Observatians on the Wheat Insect, in a Letter to the Rev. Dr. Samuel Goodenough; by Thomas Marsham, Esq.-In the third volume of the Linnean Transactions, Mr. Marsham had given an account of an insect which, in the year 1795, attacked the ears of the wheat in several parts of England. His ento

mological

mological skill persuaded him that this larva belonged to some small musca, and resembled very much those aphidivorous larvæ, which produce one particular family of the muscæ: but unfortunately none of the naturalists, who curiously observed this insect, could succeed in breeding the fly which this small larva is destined to produce. In this paper, Mr. Marsham communicates the observations of Mr. Markwick, with some remarks on them.

History of Tipula Tritiei and Ichneumon Tipule, with some Observations upon other Insects that attend the Wheat; in a Letter to Thomas Marsham, Esq. by the Rev. William Kirby.-A close observation of the metamorphosis of the above-mentioned larva has enabled Mr. Kirby to furnish Mr. Marsham, the institutor of the researches concerning that insect, with a considerable portion of satisfactory information. The larva belongs to the tipula tritici: but a little ichneumon lays its eggs on this caterpillar, and kills it. In consequence, two different insects come forth from these larvæ, and the destruction which the first species might occasion is kept in due bounds by the efforts of the second..

Account of a new Species of Muscicapa, from New South Wales; by Major-General Davies.

Observations on the genus Pausus, and Description of a new Species; by Dr. Afzelius, of the University of Upsal.-The etymology of this generic name, as explained by Dr. Afzelius,' is extremely interesting to all the admirers of the great Linné." It is derived from the Greek word ausis, signifying a pause, a cessation, a rest. Linné, old and infirm, saw in the year 1775, when this genus was first constituted, no possibility of any longer continuing his glorious career; and wishing to put a stop to his exertions, he gave this name to the last of the insects which he ever described. Though several naturalists have spoken of this insect, yet, from the blunders which they have committed, Dr. Afzelius justly suspects that none of them saw it, except Linné, Thunberg, and Fabricius.

This paper contains not only a full description of all the parts which may serve to constitute the genus, but the two species of it are described at full length, in English and in Latin. The first species is the old Linnean; the second is a non-descript brought by Dr. Afzelius from Sierra Leona.

Observations on the British species of Bromus, with introductory remarks on the composition of a Flora Britannica; by Dr. James Edward Smith. From these remarks on the composition of a British Flora, our expectations of Dr. Smith's exertions in the Flora Britannica, which he is now about to publish, rise very high; and supported as they are by the talents which he has REV. APRIL, 1800.

Bb

manifested

manifested in former publications, we are confident that this work will be as valuable as it was necessary. The examination of the difficult genus Bromus, and of twelve British species of it, which follows the remarks on the Flora Britannica, may be considered as a pattern of critical botany.

Some Corrections of the general description of Polytrichum rubellum, with an Account of another new Species of the same genus. By Mr. Menzies.-In this supplementary paper, (see page 365,) the new species described is the Polytrichum subulatum, gathered in New Zealand by Mr. Nelson.

An account of the Vth volume is preparing for our next Number.

ART. V. An Account of the Operations carried on for accomplishing a Trigonometrical Survey of England and Wales; from the Commencement, in the Year 1784, to the End of the Year 1796. Begun under the Direction of the Royal Society, and continued by Order of the Honourable Board of Ordnance. First published in, and now revised from, the Philosophical Transactions, by Captain William Mudge, F. R. S. and Mr. Isaac Dalby. Vol. I. Illustrated with 22 Copper-plates. 4to. PP. 457. 11. 8s. Boards. Faden. 1799.

THE memoirs relative to the trigonometrical survey being published only in the Transactions of the Royal Society, and consequently not generally accessible, Mr. Faden has been induced to re-print in a separate work whatever has been published on that subject; and the arrangement of the several materials of this work has been entrusted to Captain Mudge and Mr. Dalby. Concerning the alterations made by them in the original papers, we are thus informed in the preface:

In proceeding to narrate the innovations made in the original papers, we shall begin with observing that, the principal articles, as well as the plates, have been respectively numbered in succession, for the conveniency of reference during the reprinting of the work. No material alterations will be found in General Roy's Account of the Measurement on Hounslow Heath, if we except a correction of about eight inches in the reduction of the base, which was 27404.7 feet, instead of 27404.01. For this reason, all the sides of the prin cipal triangles to the xivth and the distances depending on them, in the account of the operation in 1787, 1788, are reduced in the proportion of 27404.7 to 27404.2; the latter being a mean of the two measurements (p. 138). The other deductions, to the eastward, are derived from the mean distance of Hollingborn Hill and Fairlight Down, resulting from both bases (p. 142). This second account, however, follows the original, with a few variations, till Art. 57, excepting the reduction of the base of verification (Art. 25.) which is corrected, and given in another form. What is inserted between x11th and xivth triangles, with the remainder of the same Article after the xxxviith triangle, are additions. The triangles on

the other side of the Channel, in Pl. XIV. which were numbered from XXXVI. to XLIV. are omitted in the text, as M. M. Cassini, Mé chain, and Legendre have now published their own corrected account. entitled "Exposé des Opérations faites en France en 1787, pour la Jonction des Observatoires de Paris et de Greenwich;" but what was necessary for the triangular connection, is taken from that publication. From this Article to the 79th, the whole, but two or three pages, is written de novo, and, in some respects, may be considered as an abridgment: nothing, however, is omitted but what appeared either unnecessary, or not immediately connected with the principal design. What relates to the meridional degree, resulting from the combined operation, is much more copious. And, in the Article on the difference of meridians of Greenwich and Paris, an answer is given to some objections of M. Lalande. The Longitude of Paris, in this Article, is 2° 19' 51", which exceeds that in the original publication, or 2° 19′ 42′′, this latter being computed with the perpendi cular degree, as derived from the operation in Kent (Art. 68.); but it cannot be considered so accurate as the other result, for the reasons

given in p. 167. 303. That 61182 fathoms is, very nearly, the length of a degree of a great circle perpendicular to the meridian in latitude 50° 41', cannot be doubted, since the observations at Dunnose and Beachy Head (Art. 102.) were made with great care, and are sufficiently numerous: but, the method of determining differences of longitude by angular measurement being totally new, it must, as a matter of course, rest on its own principles, till comparisons can be drawn from similar operations. Were other degrees perpendicular to the meridian, or of longitude, measured in remote latitudes, it might, perhaps, enable us to distinguish among the different meridional degrees already obtained, those which ought to be rejected, in order to reconcile the greatest number of results from both methods of operation, to some regular figure of the earth. In M. Cassini de Thury's book, Le Meridien verifié, we find an account of the first arc of longitude, which seems to have been measured with tolerable care. The operation was performed in lat. 43° 32', on a distance of about 97 miles between the stations Cette and St. Victoire (lying nearly east and west) in the south of France: the distance being ascertained by means of a chain of triangles, the times of the instantaneous explosion of gunpowder, fired at a central situation, were noted at the stations, and thence the degree of longitude was inferred, being 44358 fathoms; which, however, appears not to have been considered as conclusive by the French mathematicians.

The rules in Art. 72, for computing the mean refractions and relative heights are, in substance, the same with those given in the account of 1795 and 1796: they are shorter and much more direct than those which are given for that purpose in the original account. The corrections in the secondary triangles, with the bearings of the stations, (Art. 59.) and most of the additions in the latter part of Art. 57, are taken from the remarks in the second part of the Philosophical Transactions for 1790. And to those secondary triangles are now added the bearings, with the computed latitudes and longitudes of 32 of the intersected objects. Bb 2

• The

The note p. 5 is, perhaps, unnecessarily retained, as it seems to allude to the Paper published by Doctor Maskelyne two years after in the Philosophical Transactions for 1787.

The accounts of the Survey, from 1791 to 1796, are printed from the originals, without any other alterations, but such as were deemed necessary for giving the whole an appearance of uniformity, as far as the different parts would admit. The variations, however, principally consist in transferring Articles 113, 146, from the latter to the former of the two accounts. In our paper of 1795 and 1796, it will be found that, the distances of some of the intersected objects, from the meridian and perpendicular of Greenwich, vary, in a trifling. degree, from those given in the account of 1796. These differences arise from a part of the former computations having been made with 27404.7 feet, the length of the base on Hounslow Heath as given by General Roy, and those which are at present spoken of, with 27404.2 feet, the mean of the two measurements, Art. 172. These refinements do not, of course, materially affect the conclusions in that part of our former work, to which we refer.,

The latitudes and longitudes of the stations in the Survey of 1795 and 1796, as well as the objects intersected from them, do not appear in the original Account. When that Paper was drawn up,there were not sufficient data for computing those arguments: but, we have since obscrved the direction of the meridian at the stations on Blackdown in Dorsetshire, Buttertonhill in Devonshire, and St. Agnes' Beacon in Cornwall. These observations will enable us to supply this omission in the next Account we present to the Royal Society. With respect to the Plates, the XVth is entirely a new one, and the XXth is reduced to its present size, from that given in the first Account, for the purpose of commodiously folding into the volume.?

Of this work, since the several parts have already appeared before the public, a critical examination will not now be expected from us. The volume is handsomely printed, and the plates, which are very numerous, are well executed. This first part contains, a Measurement of the Base on Hounslow Heath, in 1784: Trigonometrical Operations, in 1787, 1-788: Trigonométrical Survey, 1791, 1794: TrigonometricalSurvey, 1795, 1796.

ART. VI. Two Successive Tours throughout the whole of Wales, with several of the adjacent English Counties; so as to form a compre:hensive View of the Picturesque Beauty, the peculiar Manners, and the fine Remains of Antiquity, in that interesting Part of the British Island. By Henry Skrine, Esq. 8vo. Pp. 280. Boards. Elmsley and Bremner. 1798.

Gs.

HOSE who have read Mr. Skrine's tours in England and Scot land, which were noticed in our 19th vel. N. S. p. 322. will not need any particular recommendation of this work.

The