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The Phosphates of America. 



of brick, or of iron, or in fact any suitable material in accordance 

 with the fancy. It stands over the dividing wall of two " dens ;" is 

 generally provided with movable traps for discharging its contents 

 at either of its ends and with a revolving axle or shaft fitted with 

 arms or spirals. It should have a hopper and a gas-flue, and the 

 driving gear must be of wrought-iron. Running into it from the 



SIDE VIEW OF A SUPERPHOSPHATE WORKS. 

 A, Discharge from mixer to " den." 1, 2, 3, 4, Exit-flues conducting fumes to condenser, 



top directly under the hopper is a 2 -inch lead pipe fitted with a 

 stop-cock and connected with a tank of sulphuric acid placed di- 

 rectly overhead. The acid tank is provided with a gauge which 

 shows the exact amount of liquid run into each batch as required 

 by calculation. The tank communicates in its turn with the acid 

 reservoirs from which, when emptied, it is replenished by a pump. 

 The phosphate is brought forward from the mill in buckets on an 



