1830.] 
253 
Description of a Plunger Pump . 
from a double crop : for it is invariably the case, that the primary crop is always 
an inferior one from land so used; and I am much inclined to think, indeed, tha>- 
tke practice of douVile cropping is not profitable. — These observations are not in- 
tended to apply to the immediate vicinity of towns whence, from the facilities 
offered to manuring, such practice would be undoubtedly profitable. As a gene- 
ral assertion, it may be truly stated, that manuring, as a practice, does not pre- 
vail in my part of the country; the few and limited exceptions bearing the same 
proportion as a river to the immensity of the ocean. Now no land, of however 
superior a quality, can be constantly cropped without manure ; it must be re- 
cruited either by fallowing or manuring. Manuring (save in especial instances) 
can never obtain in this country till the number of cattle is largely incieased, 
till the raints have more interest in the good cultivation of the land than they now 
have, by being allowed a larger share of the produce of their industry ; and till 
the dung of animals is less extensively used as fuel. Till manuring is intro- 
duced, double cropping can never be practised with advantage. In the outskiifcs 
of towns, the mfilli cultivators in this district, raise an uninterrupted succession of 
crops. These are vegetables chiefly. And I suppose that vegetables also con- 
stitute the crops noticed by your correspondent ; for it is evident, that neither 
wheat nor any other grain could be produced at the rate of six, 01 even three 
crops per annum. Wheat, with the time occupied in the preparation of the ground, 
takes seven mouths to mature ; rice five, &c. ; and sugar-cane at least fifteen 
months. The average which I noted was confined to these crops, fiheie is a 
difference in the rate of rent for sugar-cane of a rupee per biga in this district, 
when the cane is grown on land on which a Jcfiarif crop has been previously 
sown ; and this, too, when manure is given in the largest quantities in the power 
of the cultivator. As about from 4 to S annas may be paid foi the kharif crop, 
the diminution of the reut of the crop is, say 8 annas per biga, or somewhere 
about 1^ rupee in the value of the produce. The practice is seldom resorted to, 
and is considered to be disadvantageous. 
August, 1830. 
VIII. — Description of a Plunger Pump. (With a plate.) 
My dear Sir, 
Enclosed I have the pleasure of sending you a sketch of the Pump 
I mentioned to you some days ago, and which I have found to exceed the ex- 
pectation 1 had formed of its operation. I will endeavour, however, to explain 
the mode in which it is constructed, and its powers ; and if you think it suffi- 
ciently intelligible, pray dress it up a little, and request the Editor of the 
“ Gleanings” to insert it. 1 have not just now any of the numbers of that work, 
in which the various modes of raising water are set forth, or 1 would endeavour 
to draw a comparison, the only true test of its utility. 
The Pump in question is a double stroke “ plunger pump,” (see PI. II. ) and con- 
sists of one square main trunk; with two boxes at its lower extremity, for the 
plungers to work in, one cross beam (formed of plank) at the top, and two spars, 
for plungers. 
The trunk is formed of three dunnage deals, about 11 inches by 3, and 15 feet 
long; one plank is cut in two lengths of 5% by 3, which, inserted between the 
other two planks, form two sides of the trunk ; while the two whole plaoks 
form the other two sides, leaving the trunk, in the clear, about 5 inches. The 
plunger boxes are made of teak, and fitted to the trunk with a rabbit, and 
secured by two iron hoops, driven on, one near the top, and the other near the bot- 
tom, which not only fix the boxes firmly against the trunk, but prevent their ends 
from yielding to the pressure of the tampions 1 , which must be driven in with some 
force, to render them water tight. The plungers are two fir spars, and the part 
which works in the collar is about 3 feet long by 5 inches diameter, and are 
cylindrical ; all above this is tapered away, to avoid superfluous weight. To the 
lower part of this trunk, within two or three inches of the bottom, are fitted two 
valves, opening inwards, opposite to each other. The plunger boxes, which are 
1 These tampions are square pieces, cut to fit the open ends of the plunger boxes, 
and the lower end of the main trunk, and are driven in tight, with a strip of parcel- 
ling round them. 
