LEA 
that furface covered with either hairs or down ; and 
on, the contrary, where the under furface was garnifti- 
ed with either hairs or down, the moifture was im- 
bibed by that furface. He like wife, mentions many 
experiments made by himfelf, and alfo by Monf. 
du Hamel de Monceau, of the Royal Academy of 
Sciences at Paris, in rubbing the Leaves over with 
varnifh,. oil, wax, and honey, to fee the effedt of 
thefe upon various Leaves, fome of which were rub- 
bed over on both furfaces, others only upon one; 
fome only a part of the furface, others the edges 
of the Leaves' were rubbed over, and in fome only 
the foot-ftalks of the Leaves were rubbed with 
thefe. They likewife -anointed the trunks of fome 
trees and fiirubs, and left the Leaves and branches 
in their natural ftate. 
The refult of thefe experiments was, that where the 
Leaves were anointed on both furfaces with varnifh, 
they decayed prefently ; and where they were anointed 
with the other things, in proportion as thofe were 
mod penetrating, fo the Leaves continued a fhorter 
time than the others ; and where one furface only 
was anointed, they continued much longer than thofe 
which were anointed on both ; and where the pedicle 
only was anointed, they continued ftill longer ; but 
the anointing of the trunks, made no fenfible alter- 
ation, excepting in very hot weather ; when they both 
imagine, that the anointing them was of fervice, by 
hindering the too great tranfpiration which might 
weaken the trees •, for they obferved, that thofe trees 
which were varnifhed, fuffered lefs from the violent 
heat, than the trees which were left in their natural 
ftate. 
Monf. Bonnet alfo obferved, that thofe Leaves which 
were varniflied, the tender parts of the Leaves were 
deftroyed by it, and the tough fibres only were left 
remaining. 
As it would fwell this work much beyond its intended 
bulk, were I to mention more of thefe curious ex- 
periments, 1 fnall refer the curious to his book, 
where they will find a great number of the moft ac- 
curate and well condu&ed experiments related, to 
afcertain the ufes of the Leaves of plants in ve- 
getation. 
The before-mentioned Rev. Dr. Hales, in his Trea- 
tife of Vegetation, fays, it is plain from many expe- 
riments and obfervations he had before mentioned, 
that Leaves are very ferviceable in this work of vegeta- 
tion, by being inftrumental in bringing nourifhment 
from the lower parts, within the reach of the at- 
traction of the growing fruit, which, like young ani- 
mals, is furnilhed with proper inftruments to fuck 
it thence ; but the Leaves feem alfo defigned for 
many other noble and important fervices ; for na- 
ture admirably adapts her inftruments, fo as to be at 
the fame time ferviceable to many good purpofes. 
Thus the Leaves, in which are many excretory duds 
in vegetables, feparate and carry off the redundant 
watery fluid, which, by being long detained, would 
turn rancid, and prejudicial to the plant, leaving 
the more nutritive parts to coalefce ; part of which 
nourifhment, we have good reafon to think, is con- 
veyed into vegetables through the Leaves, which 
plentifully imbibe the dew which contain fait, ful- 
phur, &c. 
For the air is full of acid and fulphureous particles, 
which, when they abound much, do, by the adion 
and -readion between them and the elaftic air, caufe 
that fultry heat which ufually ends in lightning and 
thunder; and thefe new combinations of air, ful- 
phur, and acid fpirit, which are conftantly forming in 
the air, are doubtlefs very ferviceable in promoting 
the work of vegetation ; when, being imbibed by 
the Leaves, they may not improbably be the mate- 
rials, out of which the more fubtile and refined prin- 
ciples of vegetables are formed ; for fo fine a fluid 
as the air feeros to be a more proper medium, wherein 
to prepare and combine the more exalted principles 
of vegetables, than the groffer watery fluid of the fap : 
LEO 
and for the fame reafon it is likely that the moft re- 
fined and adive principles of animals are alfo prepared 
in the air, and thence conveyed through the lungs into 
the blood ; and that there is plenty of thefe fulphureo- 
' aereal particles in the Leaves, is evident from the ful- 
phureous exfudations that are found in the edges of 
Leaves, of which bees are Obferved to make their 
waxen cells, as well as of the dull of flowers. And 
that wax abounds with fulphur, is plain from its 
burning freely, &c. 
We may therefore reafonably conclude, that one great 
ufe of Leaves is what has been long fufpeded by 
many, viz. to perform, in fome meafure, the fame 
office for the fupport of the vegetable life, as the 
lungs of animals do for the fupport of animal life ; 
plants, very probably, drawing through their Leaves 
fome part of their nourifhment from the air. 
LEDUM. Raii Syn. i — 142. Lin. Gen. Plant. 483. 
Marfh Ciftus, or wild Rofemary. 
The Characters are. 
The flower has a flmall empalement of one leaf, in- 
dented in five parts. It hath five oval , concave , fpr end- 
ing petals, and ten fender Jiamina the length of the pe- 
tals which fpread open , terminated hy oblong fummits , 
and a roundijh germen fapporting a fender fiyle , crowned 
by an obtnfe ftignia. The germen afterward becomes a 
roundijh capfule with five cells , opening at the bafie in 
five parts , and filled with finally narrow , acute-pointed 
feeds. 
This genus of plants is by Dr. Linnsus ranged in 
the firft fedion of his tenth ciafs, intitled Decandria 
Monogynia, which includes thofe plants whofe flowers 
have ten ftamina and one ftyle. 
We have but one Species of this genus, viz. 
Ledum ( Paluftre ) foliis linearibus fubtus hirfutis, fiori- 
bus corymbofis. Flor. Suec. 341. Ledum with very 
narrow leaves , hairy on their under fide, and flowers grow- 
ing in a corymbus. Rofmarinum fylveftre minus nof- 
tras. Park. Hift. 76. Our [mail wild Rofemary. 
This plant grows naturally upon modes and bogs in 
many parts of Yorkfhire, Cheffiire, and Lancashire, 
where it rifes with a flender flirubby ftalk about two 
feet high, dividing into many flender branches, which 
are garnifhed with narrow leaves not much unlike 
thofe of Heath. The flowers are produced in fixjall 
clufters at the end of the branches, which are fhaped 
like thofe of the Strawberry-tree, but fpread open 
wider at the top. Thefe are of a reddifh colour, 
and appear in May, and in the natural places of their 
growth, are fucceeded by ieed-vefiels filled with frnali 
feeds, which ripen in the autumn. 
It is with great difficulty this plant is kept in a gar- 
den, for as it naturally grows upon bogs, fo unlefs 
the plants have fome fuch foil and a fhady fituation, 
they will not thrive. The plants muff be procured 
from the places of their growth, and taken up with 
good roots, otherwife they will not live. They can- 
not be propagated in gardens, but in the moffes their 
roots fpread and propagate pretty freely. 
LEEKS. See Porrum. 
LEGUMES, or L E G U M E N S, are a fpecies 
of plants which are called pulfe, fuch as Peas, Beans, 
&c. and are fo called, becaufe they may be ga- 
thered by the hand without cutting. Mr. Ray reck- 
ons all thofe plants which have a papilionaceous 
flower, among the Legumes ; but the French com- 
prehend moft forts of efculent plants, under this ge- 
neral title of Legumes. 
LEGUMINOUS, of or belonging to pulfe. 
LEMNA. Lin. Gen. 1038. Lens Paluftris, Duck- 
Meat. This is a very common plant, growing upon 
Landing waters in moft parts of England where, if 
it is not difturbed, it will foon cover the whole 
furface. 
L E M O N-T R E E. See Limon. 
LENS. See Ervum. 
LENTISCUS. See Pistacia. 
LEONTI CE. Lin. Gen. Plant. 423. Leontopeta- 
lon. Town. Cor. 49. tab, 484. Lion’s Leaf, 
The 
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