VOLATILE MATTER IN FUELS. 
39 
from the third result by the official method was 7.25 per cent, or the 
loss of ash 3.9 per cent. Correction for fixed carbon mechanically 
carried off is accordingly 3.9^11.15, or 35 per cent. This portion of 
the fixed carbon as shown by the modified method gives 11.4 per cent 
as the amount of fixed carbon expelled mechanically. The result, 
after making the fixed-carbon and ash corrections, is shown in column 
2 of the following table: 
Corrected determination* by the official method. 
Constituent. 
Corrected results. 
1. 
2. 
19.78 
47.10 
21.97 
11.15 
19.78 
43. 42 
25. 05 
Ash 
11.15 
100. 00 
100. 00 
The difference in this case in fixed carbon, due to the different heat 
treatment, is 7.07 per cent. 
This particular sample was very finety ground. To find out how 
much the difference in result was due to the fineness of grinding a 
duplicate portion of the same sample was ground down till it passed a 
40-mesh sieve. The results of duplicates by the official method and 
by the modified method are shown in the next table. The proximate 
analysis of the first sample by the modified method is shown in column 
2. The correction for fixed carbon to be applied to the result of the 
official method is 0.95-^11.20, or 8.5 per cent of the fixed-carbon 
result of the modified method, which is 2.9 per cent. The results by 
the official method, after correcting for mechanical loss of fixed carbon 
and ash, are shown in column 1. The difference in fixed carbon be- 
tween the two methods, due to different heat treatment, is 3.45 per 
cent. These resr ':-? show, at least for lignites, that the fineness of the 
sample has an important effect. Upon a second sample of lignite, 
similar to the first except that it contained more moisture (30.45 per 
cent), the average results by the modified process are as tabulated in 
column 4. A comparison of the results in volatile matter and ash by 
the official method shows that the correction to be applied to the fixed 
carbon and ash for mechanical loss is 2.71-^-10.83. These corrections, 
as applied to the results obtained by the official method, are shown in 
column 3. 
