SYPHONS.

Otago Daily Times, Issue 1943, 23 March 1868, Page 5

SYPHONS.

(To the. Editor of the Otago Daily Times.) Sik—There is a letter signed "W.C." in your issue of date 17th of the present month, to which I beg to offt»r a few words in reply. The letter is modestly written, and the writer seems desirous of informa tioa, and offers his suggestions in :i proper spiritjbutas he seems to be somow3:-i' unacquainted with the principle upon wbLh the syphon acts, I take the liberty of answering his leading question. He asks, " Would it not have been practicable and simple to have taken advantage of tho cup-like shape of the reservoir and tho steep descent, by leading tho water right out over the embankment, through the medium of a syphon ?" I answer, emphatically, no ; a syphon could not possibly act. The depth from tho base to the top of the bank is 63ft. Now, the syphon could only act where the depth was less than 33ft. Atmospheric pressure is tho pressure upon which the isyphon acts. The atmosphere presses at tho rate of 151bs to the square inch, at the ocean's level, and the pressure is equal to tho weight of a column of water 33ft in height The pressure diminishes the higher we rise, and as the reservoir is higher than the sea level, the pressure must be somewhat less. A syphon could act were the batik 20ft. lower than it is, but that would limit its utility, would keep persona Jiving in the higher parts of tho city from enjoying the luxury of an abundance of pure water. There aro other difficulties in the way ; bui enough has been shewn of the inutility of the syphon. Let "W. C." suggest something elso. Nothing was ever uttered of higher -import, than the words, "try again."—l am, Ac., J. G. Waikari, 18th March, 18G8.