236 
THE CULTIVATOR. 
August, 
Construction of Cisterns. 
In consequence of the repeated inquiries we receive 
for information relative to the best construction of rain¬ 
water cisterns, we are induced to furnish some brief 
practical hints on the subject. The great value of an 
abundant supply of water to houses and bams, and 
which may be easily had by providing capacious cis¬ 
terns, renders it important that the cheapest, best, and 
most convenient mode of construction should be adopt¬ 
ed. 
The two all-essential requisites for under-gronnd cis¬ 
terns,. are good hydraulic lime, and a supply of 
clear pure sand. These must be selected from experi¬ 
ence or trial, or by choosing such as have already prov¬ 
ed efficient for this purpose. Good hydraulic cement 
will in the course of a few months become about as hard 
as sandstone. When this hardening process does not 
take place, it must be attributed to bad materials, or 
to intermixing in wrong proportions. On the latter 
point, some are misled by adopting the practice em¬ 
ployed in mixing conmon lime mortar, the hardest ma¬ 
terial resulting in this case where the sand consti¬ 
tutes about five-sixths of the whole. But the hard¬ 
est water-lime mortar cannot be made if the sand 
forms much more than two-thirds of the whole. 
A very common and a cheap form for the cistern is 
to dig a round hole into the ground with sloping sides, 
somewhat in the form of a narrow-bottomed tub, and 
then to plaster immediately upon the earth, fig. L. Un- 
Fig. 1. 
less a slope is given to the sides, the mortar cannot be 
made to keep its place while soft, as it is nearly im¬ 
possible to find a soil dry and hard enough to retain 
the plastering by simple adhesion. The top of this 
kind of cistern must therefore be wide, and consequent¬ 
ly difficult to cover very large ones effectually and sub¬ 
stantially. The covering is usually made by stiff and 
durable plank, supported if necessary by strong scant¬ 
ling, and over this is placed about one foot of earth to 
exclude completely the frost. A hole with a curb, 
about eighteen inches by two feet, must be left in this 
covering, for the admission of the water pipe or pump, 
and to allow a man to enter for cleaning out the cis¬ 
tern when necessary. In cold or freezing weather, it 
is indispensably requisite to have this hole well stopped 
to exclude frost, which would otherwise enter the wet 
cement or walls, and produce cracking and leakage— a 
frequent cause of the failure of water-lime cisterns. 
This is the cheapest form of such reservoirs, but a 
better, more capacious, and more durable mode is to 
dig the hole with perpendicular sides in the form of a 
barrel, and build the walls with stone or hard brick, to 
receive the plastering. (Fig. 2.) In consequence of its 
circular form, operating like an arch, these walls will 
not be in danger of falling if not more than half the 
ordinary thickness of similar walls. For large cisterns 
they should be thicker than for small ones. The walls 
should be built perpendicular until about half way up, 
when each successive layer should be contracted, so as 
to bring them nearer together, in the form of an arch, 
reducing the size of the opening at the top, and ren¬ 
dering a smaller covering necessary. If the subsoil is 
always dry, or never soaked or flooded with water, the 
walls may be laid in common lime mortqr, and after¬ 
wards plastered on the inner surface with the cement. 
But. in wet subsoils, the whole wall should be laid in 
water lime. If the bottom is hard earth or compact 
gravel, a coating of an inch or two may be spread im¬ 
mediately upon the earth bottom ; but in other instan¬ 
ces the bottom should be first laid with flat stone, or 
paved with round ones, the cement spread upon these. 
The plastering upon the sloping earth walls as first 
described, (Fig. 1,) should never be less than an inch 
thick, and if the earth is soft, it should be more. On 
the stone or hard brick walls, (Fig. 2,) half an inch 
will be thick enough. Cistenis can rarely if ever be 
made free from danger of breaking, without giving 
them at least two successive coats, and three will be 
safer—the previous coat in each instance being allow¬ 
ed to become dry and hard. 
As the best mortar begins to harden in a very short 
time after mixing, it is best to mix the lime and sand 
dry , and to apply water to small successive portions as 
wanted. —«©.— 
The Cherry Slug. —This larva, which eats the pul¬ 
py part of the leaf of the cherry, and sometimes of oth¬ 
er fruit trees, is most effectually routed by a sprink¬ 
ling of lime. Air-slacked lime, applied in the dew of 
the morning, usually accomplishes the desired purpose. 
Dry, water-slacked lime, taken fresh, is still better, be¬ 
ing more caustic. 
