The Jantu.

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Chap. 12.]

duce a continuous discharge. Sometimes, openings are made in the bot-tom next the laborers, and covered by flaps, to admit the water withoutthe neeessity of wholly immersing those ends. Machines of this kind aredescribed by Belidor , but he has not indicated their origin. From theirsimplicity, they probably date from remote antiquity. They are obviously,modifieations of the Jawtu of Hindostan and other parts of Asia , andwere perhaps earried to Europe, (if not known there before) among otheroriental deviees, soon after a communication with that country was openedby the Cape of G-ood Hope.

THE JANTU.

The jantu is a machine extensively used in Bengal and other partsof India , to raise water for the irrigation of land, and is thus described byby Mr. Ward, in his History of the Hindoos. “It consists of a hollowtrough of wood, about fifteen feet long, six inches wide, and ten inchesdeep, and is placed on a horizontal beam lying on bamboos fixed in thebank of a pond or river. One end of the trough rests upon the bank,where a gutter is prepared to carry off the water, and the other end isdipped in the water, by a man Standing on a Stage, plunging it in with hisfoot. A long bamboo with a large weight of earth at the farther end ofit, is fastened to the end of the jantu near the river, and passing overthe gallows before mentioned, poises up the jantu full of water, andcauses it to empty itself into the gutter. This machine raises water threefeet, but by plaeing a series of them one above another, it may be raisedto any height, the water being discharged into small reservoirs, suf-ficiently deep to admit the jantu above, to be plunged low enough to fillit.” Mr. Ward observes, that water is thus conveyed over rising groundto the distance of a mile and more. In some parts of Bengal, they havedifferent methods of raising water, “ but the princvple is the same.”

There is in this apparently rüde maehine, a more perfect application ofmechanical Science, than would appear to a general observer. As the ob-ject of the long bamboo lever is to overcome the weight of the water, itmight be asked, why not load the end of the jantu itself, which is nextthe bank sufficiently for that purpose, and thereby avoid the use of thisadditional lever, which renders the apparatus more complex, and appa-rently unnecessarily so 1 A little reflection will develope the reasons thatled to its introduction, and will at the same time furnish another proof oforiental ingenuity. As the position of the jantu is nearly horizontalwhen it discharges the water, if the end were loaded as proposed, it woulddeseend on the bank with an increasing velocity; for the weight wouldhe at the end of a lever which virtually lengthened as it approached thehorizontal position; and this effect would be still further augmented bythe resistance of the water diminishing as the jantu rose, that is, by itsflowing towards the centre—the consequence would be, that the violentconcussions, when thus brought in contact with the bank, would speedilyshake it to pieces. Now this result is ingeniously avoided by the leverand its weight. Thus, when the laborer has plunged the end of the jan-tu next him into the water, this lever (as we suppose, for we have notseen a figure of it) is placed, so as to be nearly in a horizontal fosition, bywhich its maximum force is exerted at the precise time when it is re-quired, i. e. when the jantu is at its lowest position and full of water;and as the latter ascends, the loaded end of the lever descends, and itslorce diminishing, brings the end of the jantu gradually to rest. Asomewhat similar effect might be produced, by making the load on the le-

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