42 BULLETIN 1179, U. S. DEPARTMENT OF AGRICULTURE. 
2.50 p.m. Between this time and 5 p.m. 1,600 pounds of charge 
were added. The temperature of the gases to the stoves had at 
this time risen to 600 Q 0., but the temperature of these regenerators 
was only sufficient to heat the air delivered to the burners to 75 G 
C. During much of this time an oil pressure of 70 to 80 pounds 
was maintained which was equivalent to a consumption of between 
25 and 27 gallons per hour, but this pressure was reduced to 45 
pounds or 20 gallons per hour 48 at 6 p. m. The furnace was tapped 
for the first time at 7.10 p.m., the slag obtained being rather viscous 
and with a tendency to freeze in the cinder notches. This slag con- 
tained 8.05 per cent P 2 5i equivalent to an evolution of only 61 per 
cent, or a yield of 1.83 pounds P 2 5 per gallon of fuel oil consumed. 
The cinder notches were closed at 7.45 p. m. and from then until 
midnight a great deal of mechanical trouble was encountered, owing 
to the frequent blowing of the fuses of the motor driving the positive- 
pressure blower, and also to the fact that the oil burners became 
clogged and would not properly atomize the fuel. The distillation 
of unburned oil through the charge in the shaft deposited so much 
carbon in the precipitator that this part of the equipment had to be 
cut out until it could be cleaned. Moreover, scaffolds formed from 
time to time in the furnace shaft, owing to the alternate cooling and 
heating of this portion of the furnace, which made it necessary to 
operate for considerable periods with the top of the furnace open. 
Between the time of the last tap and 11.30 p.m., 1,325 pounds of 
briquets were charged, but owing to the irregularities mentioned 
above this was not in a very fluid condition and was not tapped 
completely out of the furnace until 8 a.m. the following morning 
(November 9), when the temperature of the hearth showed 1,600° C. 
The average phosphoric acid content of this slag (second tap) was 
8 per cent, which is equivalent to a volatilization of only 61.3 per 
cent P 2 5 . 
At 8 a. m. the cinder notches were again closed and the furnace 
recharged, 1.100 pounds of briquets being added between 9 a.m. 
and 12.20 p. m. During the first three hours of this period, however, 
the blower had to be shut off a number of times because of the 
burning out of fuses, but this difficulty was finally remedied. The 
furnace was again tapped at 12.30 p. m. (third tap), but this slag had 
a content of 10.85 per cent P 2 5 , equivalent to only 45.8 per cent 
volatilization or 1.09 pounds of P 2 5 per gallon of fuel oil. This high 
P 2 5 content in the slag reflected the adverse conditions under which 
the furnace had been operating for the previous four hours. 
The cinder notches were again closed at 1 p. m. and between 1 and 
4 p.m. 1,050 pounds of briquets were charged. The average tem- 
perature of the air to the burners during this period was 200° C. At 
3.15 p. m. a gas analysis was made which showed practically complete 
combustion of the fuel and oxidation of the phosphorus evolved. 
This analysis is given below : 
Per cent. 
PH 3 1.0 
CO a 13.2 
2 4 
CO 2.8 
N 2 82.6 
48 On account of the clogging of the burner tips from time to time, a definite oil pressure did not 
always deliver the same quantity of oil per hour. 
