And while we are fpeaking of Vermin that do Mischief to Gardens, I fhall fay a Word or two concerning the Water-Rat, which is fo great a Deftroyer of Fifh and the Roots of Trees, and prescribe a certain Way to drive them from their Habitations; we must provide a large Number of Crackers, fuch as the Boys ufe, and place them at four, five, or fix Inches Distance, upon a Yard of quick Match, which is fold by the Engineers; when we have drefs'd as many of thefe quick Matches as there are Holes of the Water-Rats, we must with a Willow Twig convey the end of the Match where we have plac'd the Crackers, as far into the Hole as poffible, only leaving a little of the Match out of the Hole; when this is done, one may provide a few Dogs to be in the Way against the Sport begins, which will be very diverting; then three or four Men with Port-fires, which are likewise to be had at the Engineers, are to be plac'd at convenient Distances from one another, and fo to fire their quick Matches at different Times, as they fee Occafion; for every quick Match immediately sets Fire to the Crackers, which will upon their going off, drive the Rats that are in that Place from their Cells, and perhaps, if the Dogs mifs of them, they may take to fome other Hole, but then he who is next to it fets Fire to that quick Match, and fo the Crackers fend them out again, as well as thofe that were in before; and by keeping on this continued Confufion among them, they quit their Station, if any be left alive, and never return to the

fame Place.

To

To Mr. Bradley, concerning the Influence of the Steam of Salt-Petre over Orchards in cafe of Blights.

S. IR,

AM fituate in a Country near a Petre-house, as we call it, or in other Terms, a House where fuch Salt-Petre as is brought from abroad is boil'd and refin'd for Gun-Powder. This Place is fo near to me, as to communicate the Steam of the Nitre, when the People are at Work, to the greatest Part of my Orchard and Garden, and, in the Opinion of fome, is injurious to my Trees and Plants; but however my Orchard is influenc'd by it, we are certain that it never fails to bring me a very plentiful Crop of Fruit every Year, though all those about it have very little or hardly any; and yet my Garden is not lefs expos'd to blighting Winds, by its natural Situation, than the other Orchards in the fame Town. If I may therefore judge from the Confequence, the nitrous Vapour, which mixes with the Air, that furrounds my Garden, prevents Blights, and is noxious to the Caterpillar. I remember Lord Bacon, in his Natural Hiftory, commends the Use of Nitre for the Prefervation of human Bodies in Health; and moft of the skilful Botanifts have given it no less a Character for the Preferyation of Vegetables, if its Quantity be rightly proportion'd. Now, as I take it, the Air, which is fuppos'd to bring Blights, is in itself thin and very quick of Motion; and therefore the nitrous Fumes, rais'd at one end of my Garden, cannot mix with fuch

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Air in too great Quantity, by means of its Thinnefs and quick Motion, for the nitrous Vapour has much groffer Particles than the fine Air which moves with it; and the Quickness of Motion of the fine Air may drive before it the Fumes I mention, with that Quickness, that there cannot lodge too much of it upon my Trees; and thus mixing indifferently with the Air, may put that Air into fuch a State, as may (agreeable to an Obfervation of yours) contribute to the Deftruction of Infects or their Eggs, which are the Blights in Trees. Or if Nitre is allow'd to be falubrious to Trees, and keep them in Strength, then I remember a Maxim, that a Body duly fupported by natural Diet is not capable of admitting any Diftemper, but on the contrary refifts it: This alludes to what I have beforemention'd, that Nitre in its due Quantity is a Preferver of Health in Plants, and more particularly because you fay in fome of your Works, that a State of Air well regulated and appointed in its Qualities, is receiv'd as well into fome Parts of Plants, and causes their healthful Difpofition, as a Cafe of that kind would do when the animal Kingdom is the Subject. It is for Reasons of this fort that I fuppofe my Orchard is not fo fubject to be blighted as the reft in our Town, which have not the fame Benefit from the Vapour of the Salt-Petre. I fhould be glad to know your Sentiments of this Matter, and am,

CHAP. XI.

Concerning the helping decayed Trees, with a Method prefcrib'd for bringing diftemper'd ones to perfect Health; with Obfervations relating to Dale Mifts.

S

O ufeful is the Discovery of the Sap's Circulation in Plants, that without that Knowledge, there could be no reasonable Method prefcrib'd for the Cure of Diftempers in Trees, or for the renewing vigorous Growth in fuch as are decay'd: This is not only good in Theory, but is excellent in Practice, as I experienc'd in an Operation upon fome old dwarf Pear-Trees, that were reduc'd to fo great Weakness, that their Fruit, which fhould have weigh'd nine or ten Ounces a piece, was hardly bigger than Hazel Nuts. Some of the Trees were canker'd a little above the Roots; their Shoots were poor and fickly, and I had fo little hopes of their Recovery, that I hardly thought it worth while to employ my Labour or Time about them; however, that I might not quite lofe fome of their kinds in their Death, I contriv'd to inarch fome of their beft Branches into free Stocks, which I had by me at that Time in good Quantity.

+

About

About the end of August I pick'd out of my Nursery about fifty of the largeft Pear Stocks I had, most of which were in the thickest Part two Thirds of an Inch Diameter; thefe I carefully transplanted at certain Distances from my fick Trees, contriving always to have every Stock within an eafy reach of one of the best Branches in my old Trees.

The Care I took in removing my Stocks gave them little or no Check, fo that the following Spring I inarch'd feveral Branches of the old Trees into them; to one old Tree I had five Stocks, to another four, and fome had only two a piece. Most of my inlay'd Grafts or inarched Shoots were perfectly join'd with the young Stocks in less than three Months; and as feveral of them bloffom'd in the Spring, the Supply of good Juices from the young Stocks, which they were graffed into, fo nourish'd the Fruit that fet upon them, that I had feveral Pears even larger than I had obferv'd before upon the old Trees when they were in Health; and the Branches of the old Trees nearest to every Stock ftrengthen'd themselves, as did alfo in Proportion every Part of the old Trees.

When the Fruit was fit to gather, I happen'd to be travelling, which was the Occafion that the inarch'd Cions were not then cut from the old Trees, but luckily remain'd all growing together. The following Year, to my Surprize, the old Trees had got fo much Vigour from the ftrong Juices of the young Stocks which circulated through them, that they had all the juvenile Appearance and healthful Difpofition of a young Tree: They fhot with so much Strength, that I then began to fear they were in Danger of lofing their bearing Quality; and therefore I

Q 2

faw'd