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TROPICAL MEDICINE AND HYGIENE 



Cork 



FIG. 72. Ross's Automatic Oiler. The cylinder is filled with oil with a spout 

 at each end. At A is a sand-filter blocking the spout and only allowing oil to 

 exude slowly. This sand-filter is a glass tube drawn out at one end, and with 

 a plug of glass wool in the cone so formed. The space above is filled with 

 sand, a small plug of glass wool placed on it, and the glass tube above drawn 

 out to a point. 



A weight is attached to the spout B a piece of galvanized wire attached 

 to each spout and joined up above. 



The cylinder is filled with oil through spout A and lowered horizontally 

 into the cesspit till the weight touches the bottom. It is then lifted up by 

 the wire attached to both spouts, and this is fixed to a nail. 



The end B will be kept down by the weight, and as long as there is oil in 

 the cylinder the end A will project upwards and oil slowly escape through 

 the sand-filter. As the oil escapes and is replaced by water, the apparatus 

 will become heavier and heavier, and at last sink and lie horizontally. When 

 this happens there is a sudden gush of the residual oil, which indicates that 

 the cylinder must be withdrawn by the wire and refilled, and replaced in 

 about ten days. 



A cylinder containing 3^ litres of oil will require refilling in about ten 

 weeks. 



