In forcing of fruit-trees people generally hang up 
thermometers under their glaffes, for the better ad- 
jufting the heat and regulating the fires •, but when 
this is°p radii fed, they Ihould be hung where the fun 
can never fhine on them, for one hour’s fun-ftfine 
upon the ball or tube of the thermometer, in the 
fpring of the year, will fo much rarefy the fpirits, 
that they will rife to the top of the tube, when, at 
the fame time, the circumambient air may not be 
much more than of a temperate heat ; but as the 
principal ufe of thefe thermometers is to regulate the 
fires, they are feldom of much ufe in the day time ■, 
becaufe, if there be only one hour’s fun-ftfine in the 
day on the glaffes, it will warm the air lufficiently for 
the production of European fruits, without any addi- 
tional heat •, wherefore there will rarely be occafion 
for continuing of the fires in the day, unlefs the wea- 
ther fhould prove very bad. And if, by the fires in 
the night, the air is warmed to the temperate point 
marked on the botanic thermometers, the fruit will 
thrive much better than in greater heat. 
There are lome perlons near London, who make it 
their bufinefs to raife early fruit to fupply the mar- 
kets, which they perform by the heat of dung only, 
having no fire Walts in their gardens. The method 
which thefe people follow, is to have a good quantity 
of new dung laid in a heap to warm (after the fame 
manner as ispraftifed for making of hot-beds.) When 
this dung is in a proper temperature of heat, they lay 
it dole on the back fide of their fruit Wall, about four 
feet thick at the bottom, and Hoping to about ten 
inches or a foot thick at the top. This dung fhould 
be gently beat down with a fork to prevent the heat 
p-oing-off too foon, but it ihould not be trodden down 
too hard, left that ihould prevent its heating. The 
outfide of the dung fhould be laid as ftnooth as poffi- 
ble, that the wet may run off more eafily ; and if there 
is a covering of thatch, as is fometimes pradliled, it 
preierves the dung from rotting too foon, whereby the 
heat is continued the longer. The time for laying 
this dung to the back of the Wall is fomewhat later 
than for making the fires, i. e. about the middle of 
February. The firft parcel of dung will continue 
warm about a month or five weeks, when there fhould 
be a fupp 3 y of new dung prepared, and the old taken 
quite away, or mixed up with this new dung, to re- 
new the heat, which, if it works kindly, will be fuf- 
ficient to laft the feafon. Thefe Walls are covered with 
glaffes or oiled paper, in the fame manner as the fire 
Walls, and the trees muft be treated in the fame wav ; 
but there mull be more care taken to open the glaffes 
againft thefe Walls, whenever the weather will per- 
mit, otherwife the ftegm of the dung will occafion a 
great dampnefs through the Wall, which, if pent in 
about the trees, will be very pernicious to them, efpe- 
cially at the time they are in flower. 
By this method fome gardeners have forced long 
Walls filled with old well-grown fruit-trees, which 
have produced great quantities of fruit annually, 
which has well an'fwered their expence •, but as, in 
many pares of England,’ it will be very difficult to 
procure a fufficient quantity of new dung for this pur- 
pofe, therefore fire Walls are moll uleful, and leaf!: 
expen five in inch places. 
I have fecn in fome places fong timber fences erefted 
to force fruit-trees, by laying new dung againft the 
back fide, in the fame manner as is p raft i fed for the 
Walls, but thefe are by no means proper, becaufe 
the (team of the dung will eafily get through every 
little crack or joint oi the boards, to the great pre- 
judice of the trees; befides, thefe boards will continue 
very damp, as long as any moifture remains in the 
dung, which will alfo be very injurious to them ; and 
as thefe boards will in a few years decay, thele will be 
more expenfive than Walls, if they are kept in repair 
for fome years, and will never anfwer the defign fo 
well. 
W A L L FLO W E R< See G heiranthus. 
W A L N U T. See Juglans. 
WA ETHER I A. Lin. Gen. Plant. 741,* 
W A L 
The Characters are. 
The flower is ofl the malvaceous tribe , and has a cup - 
JJoaped permanent empalement ofl one leaf, cut into five 
points at the rim ; it hat five heart-floaped petals which 
fprlad. open , arid five fiamina , joined in a cylinder , termi- 
nated by loofle flummits , and an oval germen , fupporting a. 
Jingle fiyle , crowned by a bifid Jiigma. The germen turns 
to an oval capflule with one cell , inclofing one obtufe feed. 
This genus of plants is ranged in the firft feftion of 
Linnaeus’s fixteenrh clafs, which includes thofe plants 
whole flowers have five ftamina joined in one body or 
column. 
The Species are, 
1. Waltheria ( Americana ) foliis oval! bus plicatis fer- 
rato-dentatis capitulis pedunculatis. Lin. Sp. Plant. 
941. Waltheria with oval plaited leaves, which are flaw- 
indented , and the flowers on foot-ftalks. Althaea Ame- 
ricana purnila, fiore luteo ipicato. Breyn. Cent. 1. f. 
57. Low American Marfij Mallow With a yellow flpiked 
ficiver. 
2. Waltheria ( Indica ) foliis ovatis ferratis plicatis, ca- 
pitulis feffilibus. Prod. Leyd. 348. Waltheria with oval „ 
flawed , plaited leaves , and the heads ofl flowers fitting 
clofe to the branches. Betonica arborelcens, villofis fo- 
liis profunde venofis, floribus ex alis foliorum glome- 
ratis. Pluk. Mant. 31, 
3. Waltheria ( Angufii folia ) foliis lanceolatis ferratis, 
capitulis pedunculatis. Prod. Leyd. 348. Waltheria 
with fpear-Jhaped jawed leaves , and heads of flowers upon 
foot-ftalks. Betonica arborefeens Maderafpatana villofa, 
foliis profunde venofis. Pluk. Aim. 67. tab. 1 50. T ree- 
like Betony of Madras , with hairy deep-veined leaves. 
This genus of plants is deferibed in the French Me- 
moirs of the Academy of Sciences, by Monf. D’lf- 
nard, who has given it the tide of Monofpermakhaea, 
from the habit of the plant being like Althaea ; and, 
having a Angle feed to each flower, he compounded 
this name ; but Dr. Linnaeus has altered it to this of 
Waltheria, in honour of Auguftus Frederic Walther, 
Profeffor at Leipfic, who is a curious botanift. 
The firft fort grows naturally in the Brafils, and alfo 
in many parts of the iflands in the Vfeft-Indies ; it has 
a foft ligneous ftalk which rifes about tw r o feet high, 
fending out tv/ o or three fide branches. The leaves 
are oblong, oval, plain, and flawed on their edges, of 
a pale yellowifli green colour, foft and hairy, and are 
placed alternately. The flowers are collefted in a clofe 
thick fpike at the top of the ftalk, having foft hairy 
empalements ; they are compoled of five petals, con- 
nefted at their bafe, which are fmall, of a bright yel- 
low colour, and fpread open ; thefe are each fucceeded 
by angular feeds which ripen in the empalement. It 
flowers in July and Auguft, and the feeds ripen in 
autumn. 
The fecond fort grows naturally in both Indies; this 
rifes with a ilirubby branching ftalk to the height of 
eight or ten feet, covered with foft hairs. The leaves 
are placed alternately upon foot-ftalks ; they are four 
inches long, and two broad in the middle, and are 
rounded at both ends, of a yellowifli green colour, 
very hairy and foft, having feveral longitudinal veins. 
From the wings of the branches arife the foot-ftalks of 
the flowers, which fit clofe to the branches, and are 
terminated by clufters of very fmall yellow flowers, 
which juft peep out of their foft hairy empalements. 
The flowers are fucceeded by a Angle feed wrapped 
in the empalement of the flower. It flowers moft of 
the fummer months, and the feeds ripen in lucceffion. 
The third fort grows naturally at Campeachy and in 
India ; from the firft place the feeds were lent me. 
The ftalks of this are ligneous ; they rife fix or feven 
feet high, dividing into feveral branches, which are lei's 
hairy than thofe of the former fort. The leaves are 
fpear-ihaped, about three inches and a half long, and 
one inch and a half broad ; they are of a yellowifli 
green colour, fawed on their edges, and hairy, but are 
not fo foft as thofe of the former, having many veins 
running from the midrib, handing upon long foot- 
ftalks. The flowers are very fmall, yellow, and are 
collefted into round clufters, Handing upon very fhorc 
1 4 P fo® t- 
