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LIV. Remarks on the Heat of the Air in July 1757, in an Extract of a Letter from John Huxham, M.D., F.R.S. to William Watson, M. D., F. R. S. dated at Plymouth 19th of that Month. With additional Remarks by Dr. Watson. p. 428.

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From the beginning of June last we have had a very dry season, generally very warm, and sometimes excessively hot. From the 7th to the 11th of this 'month the heat was violent; greater indeed than has been known here in the 'memory of man. I have talked with several persons, who have lived a considerable time in Jamaica, Gibraltar, and Minorca; and they severally assert, 'that they never felt such intense heat in any of these places. On the 11th, 12th, and 13th of this month, Fahrenheit's thermometer, in the shade, about 3 o'clock in the afternoon, was at 87; nay, on the 12th it was even above $8. 'Abundance of people have suffered very severely from these excessive heats:

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I putrid, bilious, petechial, nervous fevers, are exceedingly common every where. Dysenteries, hæmorrhages, most profuse sweats, affect not only those in fevers, but a vast many others. The days and nights were so intolerably hot, that little or no sleep was to be gotten. The wind we had, like, the Campsin, actually blew hot, though strong.'

On the 15th, about 7 at night, about Falmouth, Penryn, Truro, &c. a pretty smart shock of an earthquake was felt, attended with a hollow rumbling noise, throwing down pewter, china-ware, and such like. The tinners felt it 80 fathom under ground. No great damage however was done. The day before we had, about 11 o'clock before noon, a most violent hurricane, which lasted 5 or 6 minutes, attended with a heavy shower.' Thus far Dr. Huxham. The following by Dr. Watson: The heat of the air at London, during the period above-mentioned, was much greater than has been usually observed in these high latitudes; though it was never quite so severe here as at Plymouth. The annexed table exhibits the degrees of the heat, taken here upon the respective days, about 4 o'clock in the afternoon, by a Fahrenheit's thermometer. The instrument was placed in the shade; and the accuracy of the observer, who favoured me with his minutes, is not to be questioned. From hence it appears, that the air at London was, on several days hotter than it had been observed at Madeira for 10 years together: for, by Dr. Thomas Heberden's obscrvations, mentioned in the Philosophical Transactions, the heat of the air at Madeira, during that period, was never but once at 80.

1757, July















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LV. Remarks on the Letter of Mr. John Ellis, F.R.S. to Philip Carteret Webb, Esq. F. R. S. printed in the Philosophical Transactions, Vol. 49, p. 806.* By Mr. Philip Miller, F. R. S. p. 430.

Mr. Ellis, in his letter to Mr. Webb, asserts, that the American toxicodendron is not the same with Kaempfer's arbor vernicifera legitima. This assertion, says (Mr. Miller) makes it necessary to lay before the society the authorities on which I have grounded my belief that they are the same. But it may not be amiss first to take notice, that the shrub mentioned by the Abbé Sauvages is the same with that which the gardeners about London call the poison-ash. The title of it, mentioned by the Abbé Sauvages, was given by myself to that shrub, in a catalogue of trees and shrubs, which was printed in the year 1730; before which it had no generical title applied to it. And about the same time I sent several of the plants to Paris and Holland with that title, which I had raised a few years before from seeds, which were sent by Mr. Catesby from Carolina. And though this shrub had not been reduced to any genus before, yet it had been some years growing in the gardens of the Bishop of London at Fulham, at Mr. Reynardson's at Hillenden, Mr. Darby's at Hoxton, and in the Chelsea Garden, which were raised from seeds sent by Mr. Banister from Virginia; 2 of which were growing at Chelsea in the year 1722, when the care of that garden was intrusted to me.

The first intimation I had of the American shrub being the same with Dr. Kaempfer's true varnish-tree, was from the late Dr. William Sherrard, in the year 1726, when that gentleman desired me to bring him a specimen of the American toxicodendron from the Chelsea garden; which I accordingly did: and then the Doctor, and Dr. Dillenius, compared it with a dried specimen in the collection of the former, which was gathered in Japan, and which he said he received from Dr. Kompfer some years before. It appeared to those 2 gentlemen, that they were the same; and their skill in the sciences of botany was never doubted. About a year after this, I carried a specimen of the American toxicodendron to an annual meeting of some botanists at Sir Hans Sloane's in Bloomsbury; where were present Mr Dale of Braintree, Mr. Joseph Miller, Mr. Rand, and some others; which was then compared with Dr. Kaempfer's specimen, whose collection Sir Hans Sloane had purchased: and it was the opinion of every one present, that they were the same. Nor has any one doubted of their being so, who has compared the American shrub with Kompfer's figure and description of his true varnish-tree, except Mr. Ellis.

And now give me leave to examine his reasons for differing in opinion from every late botanist, who has mentioned this shrub. He says, that the midrib,

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which supports the lobe leaves, is quite smooth in the poison-ash, as is also the under side of the leaves; whereas Dr. Kaempfer, in his description of the midrib of the true varnish-tree, calls it læviter lanuginoso; and in his description of the lobes or pinnæ he says, they are basi inequaliter rotunda; whereas those of the poison-ash come to a point at their footstalks nearly equal to that at the top. These characters, Mr. Ellis thinks, are sufficient to prove that they are different plants: and he blames Dr. Dillenius for having omitted these necessary characters in his description of it; and supposes this must have misled the accurate Linneus, who quotes his Synonyma. But as Dr. Linneus is possessed of Kaempfer's book, he would little have deserved the appellation of accurate in this particular, had he not consulted the original, but trusted to a copy. But this I know he has done, and is as well assured that the plants in question are the same, as Mr. Ellis can be of the contrary. But here I must observe, that the branch, from which Dr. Kaempfer's figure is taken, is produced from the lower part of a stem, which seems to have been cut down, and not from a flowering branch; and it is not improbable that his description may have been taken from the same branch: and if this be the case, it is easy to account for the minute differences mentioned by Mr. Ellis; for it would not be difficult to produce instances of hundreds of different trees and shrubs, whose lower and upper branches differ much more in the particulars mentioned by Mr. Ellis, than the figure and description given by Kampfer do from the American toxicodendron. I will only mention 2 of the most obvious: the first is the white poplar, whose shoots from the lower part of the stem, and the suckers from the root, are garnished with leaves very different in form and size from those on the upper branches, and are covered on both sides in the spring with a woolly down. The next is the willow with smooth leaves, which, if a standard, and the head lopped off, as is usual, the young shoots are garnished with leaves much broader, and of different forms from those on the older branches; and these have frequently a hairy down on their under surface, which does not appear on those of the older. So that a person, unacquainted with these differences in the same tree, would suppose they were different. And the American toxicodendron has varied in these particulars much more, in different seasons, than what Mr. Ellis has mentioned.

Mr. Ellis next says, that the toxicodendron mentioned by Mr. Catesby, in his Natural History of Carolina, is not the same with that which is now called by the gardeners posion-ash: but I am very positive of the contrary; for most of the plants in the nursery gardens about London were first raised from the seeds which were sent by Mr. Catesby from Carolina; part of which were sent to the late Dr. Sherard, as is mentioned by him in the Philosophical Transactions, N° 367; and another part came into my hands, from which I raised a

great many of the plants, which were distributed, and some of them are now growing in the Chelsea garden. And that this shrub grows naturally in Carolina, I can have no doubt, having received the seeds of it 2 or 3 times from the late Dr. Dale, who gathered them in the woods of that country.

In my paper above-mentioned I likewise observed, that the seeds which were sent to the Royal Society by Father D'Incarville, for those of the true varnishtree, did not prove to be so; but the plants raised from them were taken to be referred to the spurious varnish-tree of Kompfer; which I believed to be the same, and own that it is yet my opinion, notwithstanding what Mr. Ellis has said to the contrary: for the number of lobes or pinnæ, on each leaf, with their And here we must obmanner of arrangement on the midrib, are the same. serve that the figure of this given by Kempfer is from a flowering branch; and every gardener or botanist must know, that the leaves which are situated immediately below the flowers, of most winged-leaved plants, have fewer lobes or pinnæ, than those on the lower branches: therefore I must suppose it to be the case in this plant; and from thence, with some other observations which I made on the seeds, I have asserted it to be the wild or spurious varnish-tree of Kompfer. But Mr. Ellis is of a contrary opinion, because the base of the lobes of those plants, which were raised from Father D'Incarville's seeds, are rounded and indented like 2 ears. In Dr. Kampfer's figure and description of the fasi-no-ki, the leaves are entire, and come to a point at their base. Here I think Mr. Ellis is a little too hasty in giving his opinion, as he has not seen this plant in the state that the branch was, from which Kompfer's figure was taken. For as there are often such apparent differences between the leaves on the lower branches of trees, and those which are at their extremities, as that in the descriptive titles of the species Dr. Linneus frequently uses them to distinguish one from another; so in making the same allowance for the plant in question, I cannot help thinking that I am in the right, and must abide by my opimon, till the plants raised from Father D'Incarville's seeds have flowered, to con vince me of the contrary.

However, I cannot help observing, that Mr. Ellis has given a title to this shrub before he had seen any of the characters, which are necessary to determine the And I have pretty good reason to believe it should not be joined to genus. the rhus; for the 3 seeds which I received from the Royal Society, were shaped like a wedge, being thicker on one edge than the other, and not unlike those of the beech-tree, as I noted in my catalogue when I sowed them; and by their structure seemed as if the 3 seeds had been inclosed in the same capsule. If it proves so, this will by no means agree with the characters of rhus: especially if the male flowers should grow on different plants from the fruit, which is what I suspect. Nor can I agree with Dr. Linneus in this particular of joining all

the species of toxicodendron to the genus of rhus, many of which have their male flowers growing on different plants from the fruit; and therefore would more properly come into his 22d class of dioecia, than his 5th of pentandria, into which he ranges the rhus. At the bottom of the characters of that genus. he has added a note, to show the varnish-tree is so. But as there are several other species, which agree in this essential character of distinction; so, according to the Linnean systein, they should be separated from the rhus, with another generical title.

Mr. Ellis observes, on the poetical description, which he says Kompfer has given of the leaves of the wild varnish-tree turning red in the autumn, that he had not found it to be the case of the tree growing in the stove at Busbridge. How it appeared in that situation, I know not: but the leaves of all those which are growing in the Chelsea-garden, and stand in the open air, do constantly change to a purple colour in the autumn, before they fall off from the shrub: but those of the true varnish-tree are much more remarkable for the deepness of their colour.

Mr. Ellis says, he had received a letter from Dr. Sibthorp, professor of botany at Oxford, in which the Doctor informs him, that there is no specimen of the true varnish-tree in the Sherardian collection at Oxford; but that there is one of fasi-no-ki, or spurious varnish-tree of Kaempfer. How the Doctor could write so, I cannot conceive; for I am very sure there was no specimen of the latter in that collection while it remained in London, having myself often viewed that part of it: and sure I am Dr. Dillenius never added that synonym to the former: and I do believe the latter was no other way known in Europe, than by Kompfer's figure and description of it, excepting that specimen of Kompfer's now in the British Museum.

I find Mr. Ellis is inclinable to think, that the poison-ash, as it is called by the gardeners, is the same with the fasi-no-ki, or spurious varnish-tree of Kampfer. The difference between these shrubs does not consist in small and minute particulars, but the most obvious striking marks of distinction appear at first sight; for the poison-ash has rarely more than 3 or 4 pair of lobes to each leaf, terminated by an odd one; in which particular it agrees with the true varnish-tree of Kampfer; whereas in the figure which Kompfer has given of the spurious varnish-tree, the leaves of 7 or 8 pair of lobes terminated by an odd one: and this figure, as I before observed, is drawn from a flowering branch. Every one, who is the least acquainted with these things, knows, that the leaves immediately below the flowers are considerably less than those on the lower part of the branches; therefore this is a more essential note of distinction than those mentioned by Mr. Ellis.

I must also observe, that Mr. Ellis would suggest, that I supposed these 2

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