The Siphon.

Manawatu Herald, 22 October 1898, Page 3

The Siphon.

PRACTICAL USE OF KNOWN .. FACT.

Mr Henry Coley set up his mill at Poroutawhao on the borders of a small lagoon of about an acre in extent and from four tof five feet deep. From this there was no outlet, and he was therefore very careful not to allow the water used for washing the green flax to enter it. By the washing troughs every mill has a stand with cross bars on which . the fibre after washing is placed prior to being taken to the bleaching grounds, so that it may free itself of as much water as possible. This wash found its way into this lagoon, and trivial though it was, sufficiently discoloured the water so that the fibre was not up to its proper colour. Something therefore had to be done. About five chains, due east, there is another Supply of water, but between the two . lagoons an uncomfortable sandhill laid, -and how to get the water without the .expense, of tunneling had to be coneidjered. : A siphon was recommended. A siVpnon In minor , matters may be described as a tent tube with legs of ur» equal length, used for drawing liquid out of a vessel by causing it to rise ?n the tube over the rim or top. For this purpose the shorter leg is inserted in .the liquid, and the air is exhausted by being drawn through the longer leg. the liquid then rises by the pressure of the atmosphere and fills the tube, and the flow begins from the lower end. The flow depends upon the difference in vertical height of the two columns of the liquid, measured respectively from the bend of the tube to the level ,o£ the water in the vessel and to the open end of the tube. The atmospheric pressure is essential to support the column of liquid from the vessel up to the top of the bend of the tube, and this height is consequently limited,

universely with the density of the liquid. At sea-level the maximum height is 34 feet for water. Mr Cofey found, by levels, that the easterly lagoon, was about three feet higher, on the surface than the mill lagoon, and that by cutting a trench at * th* 1 <jrown of {he sandhill he would 'only need to lift the Avater 19 feet. He therefore determined upon giving the siphon principle a trial, and laid the five chains with a two-inch pipe. At first there were some difficulties in keeping up the pressure from not having an air-valve, but without it, though be is procuring one, he found that by

just pouring one bucket of water into the upright junction at the top of the hill — the bend of the pipe — once a day, the flow continues uninterruptedly. Mr Coley also has this further advantage, provided it may become necessary owing to the lowering of the water in his new supply, he can easily lower the mill lagoon and thus maintain the necessary difference between the intake portion of the pipe and the outlet portion. The experience gained by Mr Henry Coley may be useful to others, and we are therefore obliged to him for the information he has afforded us.