Page:Philosophical Transactions - Volume 003.djvu/241

 and Briars, 'tis a continued, soft, loose, dry substance. In the Walnut, an observation may be made, by cutting a small and young branch, which hath the largest pith, in March, to the Pith in some branches, and through it in others of the like bigness: Whether any Sap issues out or no by the Pith, will be found by the quantity of the Sap issuing from the one and the other compar'd.

The Observations also of the Effects of Boring and Pegging the Pith, are reserv'd to the like tryal about the same time. But 'tis probable, that if the whole Pith be forc'd out, the place so bor'd will be fill'd with Sap, which will gelly there, and at length be converted into wood; as 'tis conceiv'd it does yearly between the abovesaid films, coats, and in all the pores of the Body of the Tree, and in those of the Bark proportionably, For, the Sap issuing from the Birch, cut down, turns into a white Gelly on the head of it; and likewise in those holes that are bor'd in the body of the Birch about March, by which the Tree receives its growth in all its parts.

To the 7th. Dr. Tonge, The points or ends of the Roots being cut off, they will in proportion bleed as copiously, as the Branches, and probably more; certainly longer, because there is greater plenty of juice ascended above them, than the Branches, and consequently more will issue by them, than by any part of the Tree, higher then them.

To the 9th. The same. Trees in their full growth, or near it, will probable yield more sap.

To the 10th. The same. From the latter end of January, to the middle of May, Trees will bleed. Those, that are said to run first are the Poplar, Aspe, Abele, Maple, Sicamore; some, as Willows, and the Birch, tried by my self, are best to tap about the middle of the second season; and the Walnut towards the latter end of March, They generally bleed a full Month in the whole. Mr. Midford of Durham, a very expert Gatherer and Preserver of Saps, affirms, that the Saps of the Poplar and Aspe rise so briskly in January, that they will bleed before the end of that Month. The Sycamore will run in hard frost, when the Sap freezes, as it drops. Rh