a • a I't tn sav tlwt. bv moans of a scale (jf), fr
wire ( / ) , need not M T n e i e and will give the alarm at a difference of eTsni
may be set to any ™ ff™ ;?M 7 7m -e ssio n or oleyation. I t may be occasionally used
the fourth of a degi'ee erthei “ , changes taking place in the temperature of
in gai-douing, to convey some idea the night-time; but its most
particular hothouses, to ,,„.„itals &c This balance-thermometer, as it
important uses are in domestic economy, P inventor, to the opening and shut-
S o? M ? M o r " ? 7 e s of cL in e y s , or flues, and steam-cocks, and either to
particular application of the t len ith , and the same principle may be exthermometer
is made from a proportionate increase in the diameter,
tended to any length, as ten or ™ /y ta™ o x n e te r and which enables liim to get
The apparatus which J ^ ^ 'M /PM ^ a s h e s or mndows o f’hothouses or buildmgs of any
the power requisite for opemng the ™ ™ as being cheapest from
r e r r 7 7 e n » S — » o m eighteen inches to two feet in length,
with an accurately fitted piston (i). Tliis cylinder is placed cither within or without the
hothouse or room in any convenient situation, and a cistern, or a ban-el of ordinary
dimensions, filled -with water, is placed on an elevated situation, say on a level with the
chimney-tops. The deeper the cylinder is sunk, the less the cistern requires to be raised
above the level of the floor of the house. If, as is often the case, a pipe of water is conducted
through the house from a distant reseiwoh- of ordinary elevation, then nothing
more is necessary than attaching a hranch-pipe. I t is requisite that this pipe pass
dfrectly to the point where the thermometer is placed, and at any convenient distance
under it, not higher than the bottom of the cylinder. Here it is joined to a tripartite
cock (/¡), wlicnce proceed two other pipes, one (t) to the cylinder, and tho other (m) to
a waste drain. Tho stopper to this cock turns only to the extent of about ono fifth of
a circle ; and when turned to this extent to the right, fr opens a communication between
the supply-pipe (n) aud the cylinder (A), when the pressm-e of the water in the reservoir,
whether a barrel on the top of a house, or a distant cistern, raises the piston, and by
a communication of cords and pulleys with the sashes (o) they will be raised or opened ;
and by another chain (p ), the fire or steam damper (q) iviU be opened also. When the
cock is turned to the left, this communication is stopped, and one opened between the
cylinder and waste-pipe (m)> "y which the water escaping, the piston descends, and the
sashes and dampers arc shut. The equilibrium of the balance-thermometer restored by
the temperature, being reduced or elevated to the proper degi-oe, the plug is neither
turned to tho right nor left, and every communication is closed. The cock is worked
hy two wires (r r), fastened to two short levers, flxcd on each side of the thermometer-
frame, and the other ends of the cross or handle of the cock (s s). To set the machine
at work, it is only iiecessai-y to place the scale to a degree at which it is desirable air
should be given, taking care tliat the cistern is not without water. A small cask of
w'ator regularly supplied, will answer as well as a large cistern, as the power is not as
the body of water, but as its liciglit. Where light valves or ventilators are used, the
balauce-thei-mometer of this size has sufficient power to open them without the aid of
machinci-y ; and by lengthening the tube, sufficient power may be obtained to open
balanced ivindows in dwelling-houses, chm-ches, or ho,spitals.
S e c t. V. Various Articles used in Gardeniruj Operations.
1940. The objects used in gardening, which can neither be denominated impkments nor
machines, may be classed as adapted articles, mannfactm-ed articles, and prepared articles.
S tm S E C T . 1 . Articks o f Adaptation.
1941. O f articks fitted fo r particular situations or objects, we shall notice the temporai-y
coping, horizontal shelter, movable edgings, basket-edgings, and a few others.
1942. The temporary coping is commonly a board, or two or more hoards joined, so as
to form a breadth of eighteen inches or two feet. To these boards hinges are attached,
which fit into irons ou the front upper edge of the permanent coping of the w a ll; and
thus, by means of a rod, or a cord and pidley, the board is eithei- made to project over
the fi-ont of tho waU, or is laid flat on the top of the permanent coping,
1943. The horizontal shelter is a hoard of eighteen inches broad, ancl of any convenient
length. By means of fron pins inserted in the wall, a number of these are placed horizontally,
like shelves, about the
middle and top of fruit-walls, to pro- 529
teet the blossom fi-om perpendicular
cold and frosts ; they were first recommended
by La-n-rencc, but ai-e
now seldom used.
1944. Tim netting screen (fig.
529.) “ consists of two deal poles, on
which is nailed a common fishing-
. net, previously dipped in a tanner’s
bark-pit, to prevent its being mildewed
when rolled up wet. A t the
top, the ends of the poles fit into
double iron loops, projecting a few
inches from the wall, immediately
nnder the coping ; and at the bottom
they are fixed, by a hole at the end
of each pole, upon a forked iron
coupling, which projects about fourteen inches from the wall, thereby giving tho screen a
sufiicient inclination to clear the brandies. When fr is -wished to uncover the trees, one
0 o
I f
■Iii.