38 



sions, but wasted the heat. Dampers made cf fire-clay were then used, 

 and it was found that after the superheater was hot enough to generate 

 gas freely the dampers could be safely closed. Care had been taken 

 in constructing the dampers to arrange them so that there was left on 

 the sides a space equal to about 12 inches square after they were in. A 

 further improvement in the heating was made by filling in next to the 

 stack with dirt. This bank of earth was then extended back into the 

 flue for about its length and paved on the top with bricks. There was left 

 a space of about 9 inches between the pavement and the bottom of the 

 evaporator; and in filling in the flue the combustion pipes were cov- 

 ered up for the length of the embankment. The combustion pipes 

 directly in front of the flame were soon burnt out. No detrimental 

 effects being perceptible from the loss of this air, it is safe to conclude 

 that they were of no value. 



The owner of the burners thought we would evaporate at least 15 

 pounds of water for each pound of oil burned, and hoped we would 

 reach 18 or 20 pounds. The record of the best day's work shows T-ft 

 pounds. It is but just to say that the evaporator was entirely too 

 large for the work it had to do, and the walls had time to cool before 

 starting each day. Now it is found that if the walls and surrounding 

 mediums are much lower than the temperature of the gaseous prod- 

 uct of the Buusen burners, condensation takes place and the oil is 

 fried, as it is called, instead of being generated into gas, which is 

 wasteful in the extreme. One-third of all the oil burned was generally 

 used in starting the burners each day. Another source of loss long 

 evaded our researches. It was caused by using cocks to feed oil to the 

 superheater. A common quarter-inch globe valve was substituted for 

 the cock, which brought the burners under full control and enabled us 

 to burn only one-quarter as much oil. I make the suggestion that 

 pipes for supplying oil to the superheater should should be less than 

 one-quarter inch; that globe valves less than one-quarter inch be used, 

 and that threads that regulate these valves be made as fine as pos- 

 sible, so that they may have the most delicate adjustment. I can not 

 tell the saving of all these apparent improvements, because, I had not 

 time to get the record properly. Taking the record as it is and count- 

 ing the price of oil at $1.25 per barrel, about one-half of the water was 

 removed from the diffusion juice of each ton of field cane for 31 cents 

 per ton. 



The advantages of the evaporation are: (1) Cleanliness and freedom 

 from smoke and ashes; (2) the little attention required to run it; (3) 

 the good and rapid work done. 



With rapid running the inversion is almost nothing; in fact, after 

 evaporation it is sometimes higher in purity than before, after removing 

 the scum. 



It should be remembered that the unrefinable Lima oil has been 

 quoted at the wells for 15 cents, which would lower the price for evap- 



