THE CLARIFICATION OF FRUIT JUICES. a | 
ture. Norris and McAllep (22) have published a note on the use of 
diatomaceous earth as an aid to the filtration of small quantities of 
raw cane juice in the laboratory, using brass wire screen beneath the 
filter paper in a Buchner funnel. Heriot (75, p. 205-206) describes 
a method of employing kieseleuhr on a factory scale in filtering 
‘ane juice. Zerban (35), whose paper cites a number of papers from 
the older literature on the use of kieseleuhr, has reported the results 
of both laboratory and factory scale tests of a specially prepared 
ciatomaceous earth, which was used in filtration of cane juice prepara- 
tory to filtering through carbon, with excellent results. Wooster (33) 
has patented a process of filtering raw cane juice which appears to be 
essentially identical with those of Peck (25) and Zerban (35), since 
it consists in the addition to the raw juice of kieseleuhr and filtration 
through filter presses. Martel (7S) has designed a leaf filter which 
is said to be highly effective in clarifying cane juice. The juice, as 
it comes from the mill, is mixed with specially prepared diatomaceous 
earth, agitated, heated nearly to boiling point, and forced into the 
filters at low pressure—30 pounds per square foot. Dale and Hud- 
son (8) have described a process of clarification for use with sugar- 
cane juice in sirup manufacture, the juice being heated to boiling, 
mixed with diatomaceous earth at the rate of 5 to 6 pounds per 
hundred gallons, and immediately pumped through a plate-and- 
frame filter press. With smaller quantities of the earth, filtration was 
retarded by the formation of a slimy, almost impervious coating on 
the filter cloths. The method gave a better clarification than it was 
possible to obtain by the usual methods of straining and skimming, 
and the resulting sirup was considered superior in flavor to the usual 
commercial product. Coates: (6) has reported satisfactory results 
from the use of diatomaceous earth at the rate of 12 to 16 pounds per 
ton in the filtration of tropical raw sugars in Louisiana sugar fac- 
tories, the earth, previously made to a thin cream with water, being 
added to the sugar prior to melting. — 
Paine and Walton (23) have recently presented before the sugar 
section of the American Chemical Society a report’ of a comparative 
study of various diatomaceous earths with reference to their clarify- 
ing efficiency for cane juices, finding that considerable differences in 
physical properties do not materially affect the values of the various 
earths for this purpose. 
Chace (5) has reported experiments upon grapefruit juices, in 
which satisfactory clarification is obtained by pasteurizing the 
freshly expressed juice, storing until sedimentation is completed, de- 
canting, mixing with kieselguhr, filtering through cloth, bottling, 
and pasteurizing.. Cruess (7) mentions the fact that diatomaceous 
earth may be used as an aid to the filtration of grape juices and 
