THE CLARIFICATION OF FRUIT JUICES. 21 
filtration and then by pasteurization in the final containers. A few 
preliminary experiments in the season of 1919 gave some encourage- 
ment to this idea, which was fairly thoroughly tested in the autumn 
of 1920. Several methods of handling the juices were employed. 
These will be outlined and their advantages and disadvantages 
indicated. 
TREATMENT WITH EARTH, FOLLOWED BY SEDIMENTATION, BEFORE FILTERING. 
In order to ascertain whether mixing with diatomaceous earth, 
. sedimentation, and decantation prior to filtration would be advan- 
tageous, a quantity of juice was divided into three lots. One of these 
was strained through cotton cloth, to remove fragments of pulp 
as completely as possible, and was then thoroughly mixed with 
the earth at the rate of 1 ounce of earth per gallon (6 pounds per 
hundred gallons). The second portion received an equal quantity 
of earth but was not previously strained to remove the pulp. The 
third lot was neither strained nor mixed with earth. The three lots 
were then placed in 5-gallon carboys, which were filled to the neck, 
corked, and placed in a basement room at a temperature of 55° F. for 
18 hours, to allow sedimentation to occur. At the end of this time 
the lot which had received no treatment showed a fairly compact 
precipitate about 2 inches thick at the bottom of a 5-gallon carboy; 
the other two lots showed compact deposits 3 to 34 inches thick, above 
which was a zone of less closely aggregated material, followed by 
poorly defined zones, each containing less suspended material than the 
next below. In this respect the lot which had been strained through 
cloth showed little, if any, difference from the unstrained lot. On 
carefully siphoning off the liquid it was possible to draw off 43 
gallons from the untreated carboy without greatly disturbing the 
sediment. Of the lots treated with earth, it was possible to draw 
off only 44 gallons from the lot which had been strained prior to the 
addition of earth, and 44 gallons from that which had not been 
strained, before the liquid flowing from the siphon became very 
densely turbid from the drawing up of loosely aggregated material. 
There was consequently twice as much sludge in the case of treated 
juices, but it was of a very much less compact character. 
Each of the three lots of juice was next treated with earth at the 
rate of 1 ounce per gallon, thoroughly stirred, and immediately 
filtered through a disk of earth with suction, the sludge from each 
lot being placed on the filter and drained as completely as possible 
after the siphoned liquid had passed through. A fresh filter disk 
was prepared for each lot, and uniform suction was employed 
throughout. The filtrates were equally brilliant. The juice which 
had not received a preliminary treatment with earth required about 
