1/8 MADRAS FISHERIES BULLETIN VOL. XIII, 



presses being bolted to the cemented floor, the oil and water run off 

 by channels to the receiving pit, while the press cakes are carried 

 to the drying ground, broken up, and dried in the sun, a process 

 which takes from two or three days. As the rainy season (south- 

 west monsoon period) is over when oil and guano are prepared, 

 the sun does the needful with no expense save that of a little labour 

 in spreading the stuff and in heaping and covering it at night ; 

 depredation by birds and dogs is minimized by sides and a roof of 

 old mackerel net. 



67. The separation of oil and water in the receiving pit is 

 effected in various ways. One method is an adaptation of the 

 " Florentine Vase " or separator. 



Taking advantage of the different specific gravity of two fluids 

 (e.g., oil and water) the ordinar}?^ Florentine receiver (or separator) 

 is made as a tall vessel from which an outlet pipe opens near the 

 bottom, as in a tea or coffee pot, the height of the pipe depending 

 on the difference in the specific gravities of the fluids to be separated 

 but always terminating somewhat below the normal maximum 

 level within the vessel. Hence when the two mixed fluids enter 

 the vessel the heavier separates and remain at the bottom ; as soon 

 as it rises above the lower orifice of the outlet pipe the lighter 

 fluid can no longer pass up the pipe, so that as the vessel fills, the 

 outlet pipe receives and finally discharges only the heavier liquid, 

 the lighter one filling the body of the vessel. 



68. In the separating tanks this outlet pipe is a box built 

 usually in one corner of the tank ; it may conveniently be formed 

 by a wooden plank, metal sheet, etc., placed diagonally across 

 the corner; it opens below at about 3 inches or less above the floor 

 of the tank and, has an overflow at a level slightly below the 

 surface level of the fluid in the tank ; or it may be made just large 

 enough to bale from, or a small pump suction pipe may be placed 

 in it. By either method the watery fluid is taken to another tank 

 where any remaining oil is gradually separated from it and 

 removed. 



69. Another arrangement of this class is that of dividing the 

 main receiving tank into two unequal parts by a partition, water 

 tight except at the bottom where a space of one or two inches is 

 left between the partition and the bottom of the tank : the smaller 

 of the two divisions acts like the outlet pipe of the Florentine 

 separator, since only water with some suspended oil can enter it 



