10 WASHING, COKING, AND CUPOLA TESTS. 
Owing to the fact that the power for operating the washer plant 
was furnished by a 12 by 16 inch Frost steam engine, belted to a main 
shaft from which the jigs and other machinery were driven, it Was 
impossible to change the speed of the jigs. Better results could have 
been obtained on some coals tested had it been possible to change the 
speed to suit the length of stroke used. 
As the only crusher available for this work was an 18 by 24 inch 
Cornish tooth-roll crusher, it was impossible to crush some coals down 
as fine as they should have been crushed. However, an adjustable- 
mesh bumping screen was installed in January, 1907, in such a man- 
ner that the coal was first passed over this screen, and the tailings 
then passed on to the crusher, while the fuel which went through the 
screen dropped into the bin over the jig. The product of the crusher 
was then elevated again to the screen, and this cycle of operation was 
repeated until all the coal passed through the screen. 
In December, 1906, a float and sink testing equipment was installed. 
Before each washing test was made, samples of the raw coal, quar- 
tered down to 2 kilograms each, were tested on four different specific- 
gravity solutions. In this manner it was possible to make a prelimi- 
nary determination of the result of a separation under varying per- 
centages of washed coal and refuse. The coal was then washed with 
the jig regulated to discharge as refuse a percentage about equal to 
the percentage found advisable from the float and sink tests. After 
a washing test was made, a sample of the refuse was taken and quar- 
tered down to four samples of 2 kilograms each, and these were also 
tested on the specific-gravity solutions. The test showing the high- 
est percentage of float coal and having an analysis which agreed 
fairly with that of the washed coal was then used in determining the 
percentage of "loss of good coal in the refuse." In this manner the 
efficiency of the test was shown. 
. PERSONNEL. 
John D. Wick, assisted by Edward Moore, was in charge of the 
washing tests from January 1 to June 30, 1906; J. II. Gould from 
July 16 to October 12, 1906; and G. R. Delamater from November 
15, 1906, to* June 30, 1907. 
EXPLANATION OF TABLES. 
" Percentage of reduction" and "amount actually removed." — The 
" percentage of reduction" is the comparison made of the percentages 
of the impurities in the raw coal and in the washed coal. It will be 
readily understood that if the ash alone is reduced by washing, the 
fixed carbon and volatile matter will form a higher percentage of the 
washed coal than of the raw coal. In actual practice, however, it is 
