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little : Whereas if we put other Herbs, or little Branches of the like Trees upon the brim of the Vessel, without touching the Water, they will wither and dry up in a little time. If we take a small Onion or Chibol, the Shoots of which come immediately from the bulb of the Root, and soak in Water the longest of the exterior Shoots at their extremities, letting those that are in the middle, and the bulb not touch the Water, they will continue above fifteen Days extremely green ; and I have known them grow in length above four Inches in four or five Days; but if any of the Shoots of another small Chibol like the former does not soak in the Water, those in the middle will attract but very little Juice from the bulb of the Root, and for this Reason they will grow but very little, and both will wither in three or four Days; which evidently shews that the Ends or Shoots of the Chibol, which foak in the Water, convey it from the middle, (which denotes a kind of Circulation) and that the Leaves of other Herbs, and the Branches of Trees, carry the Water which they touch into the Canals and their Stalks, whence it is communicated to the Root and other Branches when they have occafion for it.

To confirm this Opinion of the return of the Sap to the Roots of Trees, I made the following Experiment.

In a very high Row of Hornbeam, some of which joined each other at the Bark, we took two of these Trees, the Stalks of which were of the bigness of a Man's Arm; we sawed the Stalk of one of them about a foot and half below that place where the Barks united, and to hinder the Sap, rising from the Root, from re

joining

M 4

joining the parts that were cut off, we put between them a little flat Stone; this Operation was made in the beginning of the Month of February. In the Spring following the side Branches which were below the joining of the Stalks, threw out little Shoots and Leaves, as well as thofe which were above it, particularly one an Inch thick, which was half a Foot above the Incision, and about a Foot and half below the joining : It caft out also new Shoots and Leaves from the Sap of August, and from the Sap of the Spring following, in the same manner as if it had received its nourishment from the Root; which can no otherwise be accounted for than by fupposing that the Sap which rose from the other Tree, passed into the Bark of that which was cut, and being there pressed, descended to the bottom of the cut Stalk or Trunk, whence it flowed back into the fide Branches. You have seen, Sir, the success of this Experiment as well as my self, and you were pleased to take care it should be made with the utmost exactness.

I have likewise oftentimes observed, that if we cover with a very clear Glass-bell the young Plants of Melons that are raised in a hot-bed, we fee, when the Sun is very hot, drops of Dew sticking to the extremities of the Leaves, which remain very green and firm ; but if we take off the Bell there is no longer any Dew, and the Leaves wither a little, though they are no more heated than before, because they have no longer the hot Vapours of the Dung, and the Wind cools them; which is a proof that they fucked up this Dew before, and that it passed into their Jittle Canals to nourish them, the juice drawn

from

from the Root being not then sufficient to hinder them from withering.

If we foak in Water one Plant of Celandine cut off near the Earth, at the end where the Leaves are, and another cut, after the same manner, at the end which is cut, we shall see five or six hours after issue out in great abundance, yellow Juice from the fibrous Canals of that which touched the Water with its Leaves, after cutting the Stalk below the Leaves, but this Juice will not be much coloured ; whereas that of the other, the cut end of which foaked in the Water will be very much coloured, and of a very fmall quantity, if we cut it after the same manner; which cou'd not be if the Leaves which touch the Water did not partake of it to carry it into the Canals where the yellow Juice was ; and if they did not take more of it than the end of the Stalk which was also soaked in the Water.

By these Experiments we may be convinced of the necessity of the Dew, especially in hot Countries, as Egypt, where it very rarely Rains, and where the Earth which touches the Roots of Plants, continues oftentimes very dry; for to make amends for that inconveniency, there fall great Dews in Summer, the Drops of which, fucked in by the Leaves and Stalks of Herbs, serve to feed them till the Rain comes. Thus we see on almost all Plants, little points or filaments which make them look hairy, and are apparently so many little Tubes to fuck in the Dew and Rain; for aquatick Herbs, as the Watercress, Brooklime, Potamogeton, Nenuphar or Water Lilly, &c. have their Stalks and Leaves smooth and shining, and none of these little Points; neither have they any occasion for them,

because

because their Roots are always in the Water. Nor has Sorrel any of these little exterior Filaments, because its Root runs deep into the Earth where it finds sufficient Moisture.

It is not enough that there is Sap fufficient to nourish Plants, but they also stand in need of being immediately cheared by the light of the Sun, as we find by this Experiment.

Cover with a clear and narrow Glass the Earth where Purslain and Lettice has been fown, they will open themselves as they come out of the Earth, if the Sun shines upon the Glass, and grow also very well, or better than if they were exposed to the open Air ; but if you put a Pot full of Earth, where these Seeds have been fown, near a Stove, or in any other very hot place, tho' in a large and very light Room, these Seeds will rise in very loose filamina three or four Inches high, with two very small Leaves on the top, which do not any wise enlarge themselves, and will die away in a little time, as do also those which are covered with an earthen Bell in the Sun : Whence it follows, that they do not die through want of Air, but of the immediate Light of the Sun. One might try whether by putting this fame Pot at a certain distance from a great Flame in a close Place, these Seeds would thrive any better than by a heat without light.

To know how the Fruits and Seeds of Plants are brought to their maturity, we must observe and conlider a great many things. The manner which appears to me the easiest of Explication is this.

The Roots and Leaves of Plants fuck up a great deal of Water, and this Water contains very little of the other Principles of Plants; and

because

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because Water easily evaporates, and the other
Principles with difficulty, they continue engaged
in the Pores and Fibres of Plants, and there mix
and unite themselves differently according to
the particular disposition of each Plant.

There evaporates a great deal of Water every
Day, especially when the Weather is hot ; for
from a shoot of a Vine of a Foot long there daily
evaporates above two or three Spoonfuls, which
we may be convinced of when Vines congeal
in the Month of May; for two hours after Sun
rise their Shoots are black and dry, whence it
follows, that in two hours the Sun causes all
the Water to evaporate, and that in twelve
hours it would dissipate six times as much; but
though it loses a great deal of this watery Juice,
there returns enough to nourish the Plants, and
always carry thither a few of the active Princi-
ples, till at last there is enough to cause a hard-
ness and solidity in the Branches, and the Juice
of the Fruits be proper for the nourishment of
Animals; and if moreover there is too much
Water after the Fruit is gathered; this surplus
dissipates it self in a little time, and the Fruit
remains in its perfect maturity, though there
continues a great deal of Water.

Plants that last but one Year, as fennel, Poppies, &c. grow at last very hard, and the Pores through which the external Water entered shut themselves up, and the Sun continuing to dry them, there remains a great quantity of the earthy, saline, and oily Parts, perfectly mixed with some parts of Water there retained and inclosed, and which with great difficulty disengage themselves from them.

The same thing happens to Grains and Seeds, for at last they grow fat and oily, because the

watery

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