dated: 
Tho e plant gro - 
ited by heat and.the fiun’s s light e very ioe on to ae 
é&o propagating ee {pecies, or of pro- 
hi ch be ing come to erfection, the vital 
to become en ee no more 3 as iti 
too much manure, as ps as too Tile, will prevent the 
plants from thriving. By t of manure, the P ant may, 
he thinks, be conidered - as vitae and by to much, as 
heaked with food. This may perhaps be coaideee: it is 
conceived, a — analogous to hicken which 
s fo 
will lay no eggs, or very few, by feeding it too little, or 
too and it may be an Nps .perhaps as it is 
with animals, da tee much food may be hurtful to 
both. 
plants, it feems to Lim doubtful ae the brown mud re- 
maining after an infufion of dung is evapo e acl coal, 
efore i: has undergone an ignition. Ito rather, it is 
ht, tobe called an extract, and may again be diffufed 
Hage water, or diffolved, as it was be -fore the evaporation ; 
whe n it is burned into real coal, it is beco ome almoit to- 
ewly i 
ied, an antifeptic power, which { it recovers again a be ee 
iguition ; and he cannot help ftill doubting whether real coal, 
reduced even to impalpable powder, poffefles any manifett 
quality by which it deferves to be a among manures. 
The juftly celebrated Mr. Arthur ng, having put this 
powder to the haat Apras it had no rae ee effeét at all on 
o there is no doubt but that vegetables 
heir ace a good deal of food, yet he thinks 
the principal bufinefs of feeding is ss or by the leaves 
in the atmofphere. Befidesthe fa& of wf. Du Hamel de- 
{cribed abeve, tec are feveral other conideratons baie 
ie aflertion. any an 
e of all thelr raed wil die. 
{fs of t 
upo , s half a 
next day he found all the leaves and pears fallen off, andthe 
tree irrecovera lant placed unde 
its root ina phial full of water, will, he fay 
bell is exhautted by an air pump ; it willequally perith, if, 
i e air, it be immerfed in any air unfit for 
plant vegetate, without any ligt. He found even dae 
‘feeds are hurt by a ftrong light, grow flowly, and are often 
killed before eywe lobes are peor leaves, andtheir plumu- 
la and root are formed ; and that, if they furvive the aétion 
of light, they remain commonly but we form ed 
plants. This fhews, it is {uppofed, that in agriculture al 
oft all feeds not covered wi erifh, hen fun fhines 
ants, as 
for its ayaae in Beg, cue for acquiring Paleo Betting 
a lively green colour, and for its becomin ropagat- 
ing its {pecies, which propagation will not fied without 
fufficient fun-fhine, or at leaft day-lig 2 oe due pas sie 
t of the a 
eat 5 pat is to fa ay, the hea means 
the heat of the foil ; which la ft, es = aaa to 
fome ee is rather hurtful to feveral; and indeed the 
und being kept moiit by watering, is always rent cool 
y the continual oiceataryi and yet plants in general thrive 
very well in moif , though always kept cool. Trees 
ead ia principal roots to fuch a depth as 
tmolpher 
50—52 degrees of Fahrenheit’s thermometer. eWSy 
it is conceived, that the vegetation of trees, as is that of al- 
moft all plants, being dd ee or nearly fo, during the win- 
eat of hee atmofphere alone, 
without any ard - heat of the foil, nome is 
{carcely ree to va clearing ce at the furfa q 
heat of the e alone, it is thought, ae itiealees 
of trees ae panko “which motion fets, by propagation 
alfo, the juices of the roots into the fame motion: thus 
the juices drawn from the roots upwards, empty the fila- 
ments and fuckers, which by this motion upwards ay reed 
a aaeed powerfully aera without any degree eat 
being more neceflary for this oases or raurfton than 
is ceed for the {ution of an or oyle or 
Hales, (if he recolle&s well, ) aoclving a cise tube to the 
trunk of a vine cut off in the {pring, collected a very great 
ana of juice pani up by the roots ; which motion of 
he fluids in vegetables depends greatly upon their irritabi- 
lity, according to arum 3; which feems to be the 
mare cobable as an clerical explofion, direGted through a 
plant, fuch as euphorbia, flops immediately all motion in its 
uices. by extin baa the irritability. e roots thus 
abfarbiug the moifture prefented to their fuckers, ae iw 
of courte all falts, earth, metallic fubftances, &e. that can 
the 
molt part, fixed a find fome of thefe falts, 
with "all their eerie uals, in fome plants grow- 
ing in a foil impregnated as are many plants 
rowing near the fea-fhore ahi. are full of fea falt; yet 
it is not lefs true, that moft part of the ingredients imbibed 
by the roots, as well as by the leaves, tr unks, a 
undergo almoft a total change in the organs 
even fo far as to produce i in one Eo a ec ae ie and 
in another, its next neighbour, as h 
has proved be ee e, that the anon here alte can "Garni 
- anes all that. is ss a all their funGions, we 
ought not to look too anxioufly among rubbifh o r dun ngs 
for the i a natural food of vegetables, thaugh in thote 
fubftances a greater quantity of this food is at hand, ready 
prepared, and partly imbibed in the form of carbonic acid, 
mucilaze, 
