SEE 
The feveral forts of Orpine may be eafily propagated 
by cuttings during the fummer months, or by part- 
ing of their roots either in fpring or autumn •, thefe 
thrive befc in a dry foil and a Ihadv fituation, but may 
alfo be planted for the fame purpofes as the other forts, 
efpecially the fifteenth fort, which is evergreen. The 
ftalks ot this kind hang down, and have a very good 
effect in rock- work, and the plants require no care ; 
for when they are fixed in the place, they will fpread 
and propagate faff enough. 
The ftalks of the common Orpine are frequently cut 
in fummer, and fattened to laths of the fize of chim- 
ney-boards, which being framed together, are ufed 
for fcreening the fight of the fire-grates in rooms ; 
thefe ftalks will ffioot and fpread over the frame,, and 
if the frames are taken out once a week, and the 
ftalks watered over to refrefh them, they will continue 
in verdure for two months. 
SEED: The Seed of a plant confifts of an embryo 
with its coat or cover. The embryo, which contains 
the whole plant in miniature, and which is called the 
germ or bud, is rooted in the placenta or cotyledon, 
which makes the coat or involucrum, and ferves the 
fame purpofes as the fecundines, i. e. the chorion and 
amnis in animals. 
The placenta or cotyledon of a plant is always dou- 
ble, and in the middle and common center of the two 
is a point or fpeck, which is the embryo or plantule. 
This plantule, being adted on and moved by the 
warmth of the fun and the earth, begins to expand, 
and protrudes or (hoots out its radicle or root both 
upward and downward. By this it abforbs the nu- 
tritious juice from the earth, and fo grows and in- 
creafes, and the requiftte heat continuing, the growth 
continues. 
Thus, e. g. a Pea or Bean being committed to the 
ground, is firft found to cleave into two parts, which 
are, as it were, two leaves or lobes of the placenta, and 
in the fifllire appears a point, which fhoots out a root 
downward, and a bud upward •, the firft fp reading it- 
felf in the foil to catch the moiffure thereof, and the 
latter, mounting into the air, becomes the ftem or 
body of the new plant. 
It is v-ery remarkable how the plumule, or future ftem, 
fhouid always get uppermoft, and the radicle or root 
be turned downward, and this too perpendicularly to 
the horizon ; and not only this, but if, by any exter- 
nal means, the ftem be diverted from this perpendi- 
cular, and bent, for inftance, toward the earth, in- 
ftead of perfevering in that dire&ion, it makes an an- 
gle or elbow, and redrefles itfelf.- 
The fame is obferved in trees, &c. blown down, with 
their roots by the wind, or in thofe planted in pots, 
upon turning the pots upon one fide. 
Now the Seed, from which a plant arifes, being the 
plant itfelf in miniature, it is eafy to fuppofe that, 
if it be depofited in the ground with the plumule 
perpendicularly upward, and the radicle downward, 
the difpofition (hould be maintained in its future 
growth. 
But it is known that Seeds, fown either of them- 
felves, or by the help of man, fall at random, or 
among an infinite number of fituations of the plumule, 
&c. The perpendicular one upward is but one, fo 
that in all the reft it is necefiary the ftem and root each 
make a bend, to be able the one to emerge diredtly 
upwards, the other downward. Now what force is it 
that effeds this change, which is certainly an adion 
of violence. ? 
Mr. Dodart, who firft took notice of the phenome- 
non, accounts for it by fuppofing the fibres of the 
ftem of fuch a nature, as to con trad and (horten by 
the heat of the fun, and lengthen by the moifture of 
the earth ; and on the contrary, the fibres of the root 
to contrad by the moifture of the earth, and lengthen 
by the heat of the fun. 
On this principle, when the plantule is inverted and 
the root a-top, the fibres of the root being unequal- 
ly expofed to the moifture, viz. the lower parts more 
_ than the upper, the lower will contrad, and this 
SEE 
contradion be promoted by the lengthening of' the 
upper from the adion of the fun ; the confequence 
whereof will be, the roots recoiling, infinuating far- 
ther into the earth, and getting beneath the bodv of 
the Seed. ; 
In a word : the earth draws the root toward itfelf, and 
the fun promotes its defcent ^ on the contrary, the 
fun draws up the plume, and the earth in fome mea- 
lure, fends it towards the fame. 
M. De la Hire accounts for the fame perpendicular^, 
ty, by only conceiving the root to draw a coarfer and 
heavier juice, and the ftem a finer and more volatile 
one. In the plantule therefore we may conceive a 
point of reparation, fuch as, that all on one fide, e, g. 
the radial part is unfolded by the groffer^ and all on 
the other by more fubtile juices. 
If the plantule then be inverted, and the root a-top, 
as it ftill imbibes the grofler and heavier juices, and 
the ftem the lighter ; the point of feparation being 
conceived as the fixed point of a lever, the root mult 
defeend, and at the fame time that the volatile juices 
imbibed by the ftem, tend to make it mount. Thus 
is the little plant turned on its fixed point of feparation 
till it be perfectly ered. 
The plant thus ereded, M. Parent accounts for the 
fern’s continuing to rife in the vertical diredion, thus: 
the nutritious juice being arrived at the extremity of 
a rifing (talk, and there fixing into a vegetable fub- 
ftance, the weight of the atmofphere muft determine 
it to fix in a vertical pofition, fo that the (talk will 
have acquired a new part of perpendicularity over the 
reft ; juft as in a candle, which held any how oblique- 
ly to the horizon, the flame will ftill continue verti- 
cal, by the preflu re of the air. 
The new drops of juice that fucceed, will follow the 
fame direction ; and as all together form the ftem, 
that muft of courfe be vertical, unlefs fome particular 
circumftances intervene. 
And that, whereas the branches are likewife obferved, 
as much as poflible, to affed perpendicularity in moft 
inftances, infomuch, that though they be forced to 
(hoot out of the ftem horizontally, yet in their progrefs 
they erect themfelves ; M. Parent folves this, from 
the vertical tendency of the nutritious juice, up the 
ftem; for the juice, being received in this direction 
into the new tender buds, finds at firft little refiftance 
and afterwards as the branch grows firmer, it furniflies 
a longer arm of a lever to ad by. 
Mr. Aftruc accounts for the perpendicular afcent of 
the ftem, and their redrefting themfelves when bent, 
on thefe two principles. 
1. That the nutritious juice arifes from the root to 
the top in longitudinal tubes, parallel to the fide of 
the plant, which communicates either by themfelves, 
or by means of other horizontal tubes, proceeding 
from the circumference of the plant, and terminated 
in the pith. 
2. That fluids contained in tubes, either parallel or 
oblique to the horizon, gravitate on the lower part of 
the tubes, and not at all on the upper. 
From hence it eafilv follws, that in a plant pofited 
either obliquely or parallel to the horizon, the nutri- 
tious juice will ad more on the lower part of the ca- 
nals than the upper ; and by that means infinuate 
more into the canals communicating therewith, and 
be collected more copioufly therein ; thus the parts- 
on the lower fide will ad more on the lower part, and 
will receive more accretion, and be more nourifhed 
than thofe on the upper ; the confequence whereof 
muft be, that the extremity of the plant will be oblig- 
ed to bend upward. 
The fame principle brings the feed into its due fitua- 
tion at firft. In a Bean planted upfide down, the 
plume and radicle are eafily perceived with the naked 
eye, to (hoot at firft diredly for about an inch ; but 
thenceforth they begin to bend, the one downward, 
and the other upward. 
The two placentuke or cotyledons of a feed are,, as it 
were, a cafe to this little tender plantule or point, co- 
vering it up, (heltering it from injuries, and feeding; 
it 
