236 
THE WATER CRESS PATENT HYGROMETER. 
embankment should be made sufficiently high 
to keep back about one foot of water over the 
whole of the prepared bed. In this embank- 
ment a sluice should also be made so as to re- 
gulate the depth of water, or to lay it dry if 
necessary. Below this first bed others may 
be made according to the quantity wanted. If 
the bottom of the stream does not afford space 
enough, a system of alternate ditches and 
banks may be dug out of the adjoining land, 
having a leading gutter for the supply of 
water, with a sluice in it at the head of each 
ditch, and a similar gutter at the lower end to 
carry off the water. The banks should be left 
broad enough for cropping, and they will be 
found excellent places for crops of raspberries, 
strawberries, and all summer crops, from the 
facility with which they may be watered. 
When the beds are thus far prepared, the bot- 
toms should receive a thick coating of gravel, 
chalk, or some such material, if not naturally 
furnished in that way. When all is prepared 
the plants may be put in, in a regular manner, 
about a foot apart each way. The plants 
should be a moderate tuft of the strongest and 
best of the old plants, and they must be kept in 
their places by laying a large stone on each 
tuft. After planting, the water should be let 
in so as barely to cover them, and not so much 
as that, if a brisk stream can be kept up, as it 
would displace the plants. When they are 
fairly rooted and growing the water must 
be deepened accordingly, especially in frosty 
weather, when the bed in use should be 
flooded deep enough to keep the plants far 
enough under water to avoid ordinaiy frosts. 
The beds should be planted in succession every 
one, two, or three months, according to the 
demand, and the old ones destroyed. as soon as 
the plants become weak or foul. 
SIMMONs's PATENT HYGROMETER. 
Not less essential than the proper regula- 
tion of the temperature of the atmosphere of 
a plant-house, is that of its humidity ; in other 
words, an artificial atmosphere to be adapted 
to the growth of plants, must provide certain 
conditions of humidity as well as temperature, 
and it is highly important to be able to be- 
come as conversant with the former of these 
conditions as the latter — to know, in fact, 
what amount of moisture as well as of heat, 
the artificial climate contains. The thermo- 
meter, as is well known, supplies every 
facility for becoming acquainted with the 
degree of heat. Experienced ' gardeners also 
know to a considerable extent by the feel and 
smell of the atmosphere when they enter it, 
whether or not it is in a proper state as 
regards the amount of moisture, but even 
to them, some means of ascertaining the 
degree of moisture with certainty, and with 
as much facility as the thermometer affords 
the means of ascertaining the temperature, is 
of importance. Such a means is afforded by 
a new instrument, which has lately attracted 
some notice ; we refer to Simmons's Hygro- 
meter, which we shall presently describe. 
The importance of such an instrument to 
amateur horticulturists, we need not stop to 
point out, as it must be self-evident. 
In general terms, this hygrometer may 
be described as consisting of " a thin slip 
of mahogany, cut across the grain, adapted to 
a pulley and spiral spring, connected with 
a vertical arm, resembling the hand of a clock. 
This hand is made to traverse a dial-plate 
marked off into degrees, expressing the 
amount of moisture in the air, between what 
is observed when the instrument is plunged 
in water on the one hand, and exposed to 
excessive dryness on the other." Thus, when 
the hand stands at 50 degrees, as indicated on 
the dial plate, a certain specific amount of 
moisture is as clearly indicated as the heat 
connected with the rise of the mercury in 
a thermometer to 50 degrees ; and when once 
the value of the degrees as regards the 
amount of the moisture is learned, it will, 
of course, convey information of the most 
marked and satisfactory nature. 
We have had an opportunity of witnessing 
the action of this instrument, when suspended 
out of doors against a shaded wall, protected 
from wet ; and we can therefore state de- 
finitively from actual observation, that it dues 
act ; and that, too, in accordance with what is 
obviously the condition of the atmosphere 
as regards moisture. When the air is damp, 
as for instance, after a shower, the hand indi- 
cates, say 80 degrees, and probably this is 
about the point which, as a general rule, is 
suitable to stove plants. In warm sunny 
days (spring season), when, of course, the air 
is somewhat drier, we have seen it go back to 
60 degrees. These facts show that the in- 
strument works in a satisfactory way. Other 
circumstances connected with its use in the 
garden of the Horticultural Society, show 
even more forcibly its susceptibility of the 
amount of the moisture in the air. 
There are two or three conditions of some 
importance which must be attended to, in 
using this Hygrometer. It must be placed 
in the shade, for the direct rays of the sun 
would be liable to disarrange its action ; it 
must not. be hung in the wet, nor damped by 
any means, for it will be obvious that this 
would at once act on the instrument, and 
produce a false indication ; and it must not be 
subjected to greater heat than is congenial to 
vegetable life. It will be understood that 
it acts by means of the swelling of the cross- 
