20. Pinus alba; white spruce fir. Foliis solitariis tetragonis incurvis strobilis cylindraceis laxis: squamis obovatis integerrimis.

A native of North America above the 34th degree of north latitude, but it disappears southward. It is recommended by Wagenheim as a hardy, profitable tree; and is moreover one of the most ornamental of the abies tribe, growing with its branches feathered to the ground, and on account of the peculiar glaucous hue of its leaves, makes a beautiful appearance when mixed with other pines. Fine trees of this species may be seen at Milton-Abbas, in Dorsetshire, and at Paine's Hill. From its branches boiled with oats, biscuits and molasses, the American spruce beer is prepared.

21. Pinus nigra; black spruce fir. Foliis Solitariis tetragonis, undique sparsis, rectis, strictis; conis oblongis.

A native of New England, Canada, &c. The young shoots and leaves, like those of the alba, are used in making spruce beer, and by some preferred to them.

22. Pinus rubra; Newfoundland red pine or spruce fir.

Foliis solitariis, subulatis, acuminatis; strobilis oblongis, obtusis; squamis rotundatis, subbilobis, margine integris.

First propagated in this country by Mr. Thoburn, in the gardens of Mess. Whately and Barret, at Brompton, where are a few trees, but too young to produce full sized cones. Its right to be received as a distinct species is not yet fully ascertained.

23. Pinus orientalis.

Foliis solitariis tetragonis; strobilis ovato-cylindraceis: squamis rhombeis.

This species is inserted only on the authority of Tournefort, who found it growing near Trebisonde. Mr. Lambert has not seen a specimen either recent or dried, but is inclined to think some cones brought from China belong to this oriental pine. Two of these cones are figured, as is also a branch copied from a drawing made by Aubriet, under the eye of Tournefort himself, and now in the possession of M. de Jussieu.

24. Pinus picea; silver fir.

Foliis solitariis planis, subsecundis, strobilis cylindraceis erectis; bracteolis elongatis; antherarum cristâ bicorni.

In Siberia, where this species is very abundant, it is considered by the Tartar hordes as a sure indication that good

Foliis solitariis planis, subsecundis strobilis cylindraceis erectis, bracteolis abbreviatis, antherarum crista muticà.

A native of Nova Scotia, Canada, &c. Between its bark and wood are vesicles which contain a whitish transparent resinous juice, which is brought from Ca nada, under the name of Canada balsam, and apparently not very different in its qualities from the celebrated balm of Gilead exclusively the produce of amy. ris Gileadensis. From its cones, which are of a beautiful glossy deep purple colour, there exudes also a great quantity of transparent resin. Some of the largest trees of this species in England are at Woburn Park and Warwick Castle. They are said to be more than 20 years old but in this country they generally decay sooner.

26. Pinus Canadensis. Foliis solitariis, planis, denticulatis, subdistichis; strobilis ovatis, terminali bus, vix folio longioribus.

It bears a great resemblance to the common yew, but is less stiff. A large tree planted by Mr. Peter Collinson, by whom it was first cultivated here, is still standing at Mill Hill.

27. Pinus taxifolia; Nootka fir.

Foliis solitariis, planis, integerrimis, strobilis oblongis, antheris inflato-didymis.

Figured from a specimen in the Bank sian Herbarium, brought from the northwest coast of America by Mr. Menzies.

fir.

28. Pinus lanceolata; broad-leaved

Foliis solitariis lanceolatis, planis, patentibus; strobilis globosis; squamis

acuminatis.

Figured from a fine specimen in the Banksian Herbarium, brought from China by Sir George Leonard Staunton, Bart.

29. Pinus larix; larch.

Foliis fasciculatis, deciduis; strobilis

ovato-oblongis ; squamarum marginibus reflexis laceris; bracteolis panduriformibus.

The wood of the larch, cut into shingles of about one foot square surface, and half an inch in thickness, is used in Switzerland for covering the roofs of houses. At first the roofs appear white, but in the course of two or three years become perfectly black by means of the resin extracted from the pores by the sun, which also stops up the joints of the shingles and renders them impenetrable to rain. Used for subterraneous and subaquatic purposes, it is very durable, and Pallas relates that, in Siberia, some burial places of an unknown nation, and of remote antiquity, still remain with beams and supporters of larch entire.

water.

The inner part of the wood of this tree yields a pure gum, scarcely inferior in its qualities to the Arabian gum, but appears to have been hitherto used only in Russia. It is dryish, of a reddish colour; and of a subresinous taste, but wholly soluble in It is found on the Ural mountains, when the forests have been set on fire by the carelessness of the huntsmen. During the combustion it exudes from the medullary part of the trunks, and is diligently collected by the natives, not only for the purpose of rendering their bows glutinous, but also of being eaten as a delicacy.

30. Pinus pendula; black larch.

Foliis fasciculatis deciduis, strobilis oblongis; squamarum marginibus inflexis; bracteolis panduriformibus acumine attenuatis.

A native of the cold mountainous parts of North America. The first tree planted in this country grew at Mill Hill, in the garden of the late Mr. Collinson. 31. Pinus microcarpa; red larch. Foliis fasciculatis deciduis; strobilis subrotundis paucifloris; squamis inflexis; bracteolis ellipticis, obtuse acuminatis.

This species is scarce in England. The only tree of any size seen by Mr. Lambert is at Whitton, where it was planted by John Duke of Argyle. Mr. Loddige has cones both of this and the pendula sent annually from America. He has a large plantation of both species about eight foot high.

32. Pinus cedrus; cedar of Lebanon. Foliis fasciculatis perennentibus; strobilis ovatis, obtusis erectis: squamis adpressis, rotundatis.

This celebrated tree is too remarkable to be mistaken for any other species. After the excision of a branch, the part remaining in the trunk gradually loosens itself, and assumes a round form like a potatoe. If the bark covering it be struck smartly with a hammer, the knot leaps out. This fact was communicated to Mr. Lambert by Sir Joseph Banks, and he has repeated the experiment himself. The cedar is extremely tardy in its increase of size, even under the most favourable circumstances. It has no title to its common epithet, lofty; since those which still remain on Mount Lebanon are by all accounts not very high; but their wide spreading branches beautifully illustrate the allusion made to them by the Psalmist in describing a prosperous people. The diuturnity ascribed by the ancients to the wood of the cedar does not correspond with that of pinus cedrus, but applies much better to the cupressus horizontalis of Miller. The word cedar was probably used by them, as it still is by us, with considerable latitude. The wood employed as a covering for black lead pencils is not pinus cedrus, but juniperus Bermudiana.

The late Sir John Cullum has taken great pains, in the Gentleman's Magazine for March 1779, to ascertain by whom the cedar was first introduced into England, and concludes that we are probably indebted for it to Sir John Evelyn. Some of the most vigorous in this country are at Paine's Hill, Whitton, and Chiswick.

All that have been mentioned by Sir John Cullum and Mr. Lambert are in the south of England. It is, we believe, not generally known that three fine cedars are now standing at Bierley Hall, near Bradford, in Yorkshire, formerly the seat of Dr. Richardson, author of several papers in the Philosophical Transactions, and mentioned with great respect by Dillenius in his preface to the third edition of Ray's Synopsis, and also in that to his own Historia Muscorum.

The grandaughter of Dr. Richardson is still living, and from her we have been favoured with the following particulars, which she has often heard from her uncle, who succeeded his father in the possession of the estate. When cedars were first brought into England, the largest one, then a very small shrub, was sent by Sir Hans Sloane as a present to Dr. Richardson, who, concluding that it would not bear an English winter, put it into a garden pot, and for some years placed it in his green house with the other exotics; but finding that whatever it gain ed in summer by being in the open air, it lost in winter, he grew tired of nursing, and ordered his gardener to dig a large hole in the corner of his flower garden, and fill it with good earth: here he planted it, and here it grew to a noble tree, but suffered considerably about 30 years ago by a high wind which happened when its boughs were heavily laden with snow, and tore off large arms to the amount of two cart loads of timber. Its present girt, at about one foot above the ground, is twelve feet three inches; at eight feet three inches from the ground, just below its division into two principal branches, fourteen feet: the extent of its longest branch from the perpendicular of the trunk, thirty-seven feet: one of the principal branches soon divides into three, the other into two. This tree must have been sent to Dr. Richardson before the year 1685, when Sir Hans Sloane, in a letter to Mr. Ray, expressed his surprise that a cedar in the garden of Mr. Watts should thrive so well as, without pot or greenhouse, to be able to propagate itself by layers that spring: but it could not be much before, for Dr. Richardson

was not then quite 23 years old. The other two were planted some years after, and were part of a cedar hedge which was clipt for some time, but rising too high, the remainder of the trees were taken away, and only these two suffered to grow. Bierley Hall is situated in a strong clay soil, and the neighbouring country abounds in coal and ironstone. Dr. Richardson corresponded with most of the principal botanists in Europe, many of whose letters are still in possession of the family; those of Sir Hans Sloane in particular are numerous, but none in which the cedar is mentioned happen to have been preserved.

32. Pinus dammara; Amboina pitch

pine.

Foliis oppositis elliptico-lanceolatis, striatis.

This curious species of pinus was first described by Rumphius, in his Herba rium Amboinense. A specimen of the leaves is preserved in the Herbarium of Sir Joseph Banks, who has lately received fragments of the cone also from Amboina. Dr. Smith has also discover, ed a specimen of the leaves in the She rardian Herbarium at Oxford, among the plants collected by Dampier. It produces a resinous substance, described at large by Rumphius, and well known in India under the name of dammar, puti or white dammăr,

Mr. Lambert informs us that he in tends to follow up the present work with the illustrations of the remaining genera in the natural order of Conifere; and that several drawings of the species of Dacrydium, and the Dombeya of Lamarck are already finished, and will be given to the public as soon as pos sible.

A variety from Derbyshire, in minute pale yellow crystals, consisted of

Carbonic acid Oxyd of zinc

34.8 65.2

100.0

be entirely expelled from water by long boiling and the action of the air-pump, but if water having been so treated is impregnated with pure carbonic acid, the small quantity of air contained in the water will be liberated, obviously on ac

Hungary, afforded,

Water

Quartz

Oxyd of zinc

25.0 68.3

4.4

97.7 2.3

Loss

100.0

It deserves to be noticed, that the quartz, though in so large a proportion, was rendered soluble by means of the metallic oxyd in dilute sulphuric acid, as after a time the solution became gelati

nous.

3. Experiments on the Quantity of Gasses absorbed by Water at different Temperatures and under different Pressures. By Mr. W. HENRY. 10. Appendix to ditto.

The first section of this paper relates to the absorption of gasses by water, under the usual atmospheric pressure. In this Mr. Henry has observed, that the proportion of carbonic acid gas absorbed by water, by means of agitation, depends greatly on the purity of the gas made use of. Thus when at the temperature of 55°, 20 measures of carbonic acid are agitated with ten of water, at least half the gas is absorbed; but from a mixture of 20 measures of carbonic acid with 10 of atmospheric air, 10 parts of water take up only 6 of carbonic acid. The cause of this diminished absorption is merely stated to be "connected with the proportion of common air contained in the unabsorbed residuum." Undoubtedly it is; but surely we may make a nearer approach to the true reason of the fact by supposing that a partition of the carbonic acid between the water and air takes place in the compound ratio of their respective quantities and chemical affinities; whereas, when pure carbonic acid is employed, the water unites with the acid to perfect saturation, on account of the absence of antagonist affinities. But Mr. Henry is disposed to believe, with Mr. Dalton, that the "absorption of gasses by water is purely a mechanical effect," a supposition, in our opinion, very incapable of accounting for many well-known facts. Common air cannot

overcome by that of the carbonic acid.

The second section of Mr. Henry's pa per treats of the influence of pressure in promoting the absorption of gasses, and presents us with the following very im portant general law, deduced from a series of fifty experiments on various gasses, that "under equal circumstances of temperature water takes up, in all cases, the same volume of condensed gas as of gas under ordinary pressure."

4. Experiments and Observations on the va rious Alloys, on the specific Gravity, and on the comparative Wear of Gold; bring the Substance of a Report made to the Right Honourable the Lords of the Committee of Privy Council, appointed to take into Con‐ sideration the State of the Coins of this Kingdom, and the present Establishment and Constitution of his Majesty's Mint. By CHARLES HATCHETT, Esq. F.R.S.

This highly interesting paper is the joint production of Mr. Hatchett and Mr. Cavendish, and will be found, in all respects, worthy of the high reputation and acknowledged abilities of these phi losophers. The experiments were un dertaken at the desire of the privy coun cil, in consequence of a considerable loss which the gold coin appeared to have sustained by wear within certain periods, which induced them to have an inquiry instituted, in order to ascertain whether this loss was occasioned by any defect in the quality, or figure, or impression of the coins.

The subject naturally divides itself into an enquiry concerning the effects produced upon gold by various metals when alloyed with it in different proportions; concerning the specific gravity of gold variously alloyed, and the modifications to which it is liable; and con cerning the effects of friction in various circumstances. These are made the subjects of three sections, which we shall proceed to give some account of.

First, Of the effects produced upen gold by combination with other metals.

Arsenic, though it is with difficulty united with gold when the two substances are in small quantity and noted in an open crucible, yet combines easily with this metal when applied to it at a