the slightest degree of sweetness in decoctions of the wood in winter.
He therefore is inclined to believe, that the saccharine matter is ge-
nerated by a process similar to that of the germination of seeds; and
that the said process is always going on during the spring and sum-
mer; but that towards the conclusion of the summer, the true sap
simply accumulates in the albnmum, and thus adds to the specific
gravity of winter-felled wood, and increases the quantity of its ex-
tractive matter. He says also, that he has some reasons for thinking
that the true sap descends through the albumum, as well as through
the bark; and that he has been informed, that if the bark be taken
from the trunks of trees in the spring, and such trees be suffered to
grow till the following winter, the albumum- acquires a great degree
of hardness and durability.
Mr. Knight concludes by observing, that he conceives himself to be in possession of facts, which prove that both buds and roots ori— ginate from the alburnous substance of plants, and not, as he believes is generally supposed, from the bark.
Mr. Chenevix, in the month of May 1803, presanted to the Royal Society a paper, which was printed in the Philosophical Transactions for that year, respecting the nature of a metallic substance which had been offered to the public as a new simple metal, under the name of Palladium. In that paper he not only attempted to prove that the said substance, instead of being a simple metal, was merely a com- pound of platina and mercury, but he also described certain processes by which he had been enabled to produce it. He now expresses his mortification to learn that the processes he there recommended, as the least likely to fail, have been generally unsuccessful; and con- fesses he has reason to believe “ that the nature of palladium is con- sidered by most chemists as unascertained, and that the fixation of mercury by platina is by many regarded as visionary.”
In France, he says, the compound nature of palladium has been more generally credited; M. Guyton, who was appointed by the National Institute to make a report upon Mr. Chenevix’s experiments, having repeated some of them, and having been led by the results to the same general conclusions as Mr. Chenevix.
Messrs. Fourcroy and Vauquelin also made some experiments upon the subject; but as about this time a new metal had been discovered in crude platina by Mons. Descotils, the above—mentioned chemists were led to suppose it probable that the new metal was concerned in the production of palladium; and finally declared, as their opinion, that the substance called palladium does not contain mercury, but is formed of platina and the new metal of M. Descotils. Mr. Chenevix adduces several arguments to show that this opinion is not well founded; and in the latter part of his paper, he says, that
