121 



and the horizontal branches would hence soon extend so far and be- 

 come so bulky, as to render it impossible for the trunk to support 

 them. The principal office here ascribed to the horizontal and spread- 

 ing branches, is to nourish and support the blossoms and fruit, or 

 seed ; little or nothing of the sap being here returned to the parent 

 tree, and hence very feeble powers being wanted in the returning 

 system. 



Our author had long entertained an opinion that the ascending 

 fluids in the alburnum and central vessels are everywhere the same, 

 and that the leaf-stalk, the tendril of the vine, the fruit-stalk, and 

 the succulent point of the annual shoot, might in some measure be 

 substituted for each other : experiments have proved his conjecture 

 in many instances to be well founded. In several of these experi- 

 ments, leaves continued to perform their office when grafted on the 

 fruit-stalk, the tendril, and the succulent shoot of the vine ; and the 

 leaf-stalk, the tendril, and the fruit-stalk, equally supplied a branch 

 grafted upon them with nourishment. 



On examining the manner in which wounds in trees become co- 

 vered, an additional proof was found, that the medullary processes, 

 namely, the knobs of wood formed at the junction of a grafted bud, 

 with the stock in which it is inserted, are like every other part of 

 the wood generated by the bark. This is mentioned in contradiction 

 to the opinion still entertained, that the hardest, most durable, and 

 most solid part of the wood, is composed of the soft, cellular, and 

 perishable substance of the medulla. Lastly, some observations are 

 stated, which seem to imply that the sap in its descent may undergo 

 some modification which fits it more effectually to produce wood. 



A few remarks on the formation of buds in tuberous rooted plants 

 beneath the ground, are added by way of appendix. These, if the 

 above theory be true, must be formed of matter which has descended 

 from the leaves through the bark. An experiment was made on a 

 potatoe plant by intersecting its runners which connect the tubers 

 with the parent plant, and immersing thfir ends in a decoction of 

 logwood. In about twenty hours it was found that the decoction 

 had indeed passed along the runners in both directions, but that none 

 had entered the vessels of the parent plant. This result was not un- 

 expected to the author, he being well aware that the matter by which 

 the growing tuber is fed must descend from the leaves through the 

 bark, and that bark cannot absorb coloured infusions. 



Inquiries concerning the Nature of u metallic Substance lately sold in 

 London, as a new Metal, under the Title of Palladium. By Richard 

 Chenevix, Esq. F.R.S. andM.R.I.A, Read May 12, 1803. [Phil. 

 Trans. 1803,;;. 290.] 



In April last, a printed notice was circulated concerning a sub- 

 stance to which the name of Palladium, or new silver, was assigned, 

 and of which samples were offered for sale at Mr. Forster's, in Ger- 

 rard Street, Soho. A discovery of such importance did not fail to 



