12 
BULLETIN 1375, U. S. DEPARTMENT OF AGRICULTURE 
of but one thickness of copper, for if it is too heavy it will melt the 
rubber stoppers. 
If the flasks are made of glass, they should be made of the best 
grade of resistant glass and well annealed, and the necks should be 
sufficiently heavy to stand tight corking. 
When 150 cubic centimeters of oil is poured in between the two 
walls, the top of the oil should be about halfway up the sides of the 
flasks. If the flasks do not meet these specifications they should not 
be used. 
FLASK SUPPORTS 
The flask supports used in this apparatus consist of an asbestos 
ring of 14-inch transite board, 4^4 inches in diameter, incased in 
a galvanized-iron frame 5% inches square, the iron frame being 
flanged on either two sides or on all four sides to a depth of iy 2 
•Asbestos 
Fig. 11. — Flask support upon which the distillation flask rests when in place in 
the moisture tester 
inches. Each corner of the casing is cut in such a manner that 
a %-inch opening is formed. The flask support is shown in Figure 
11. This form of support exposes the bottom of the flask uniformly 
to the action of the heat, and at the same time is so made that a 
sufficient quantity of heat comes in contact with the upper part of 
the flask. 
The asbestos ring in the top of the support should be cut so that 
the bottom of the flask when in place on the support will be not less 
than three-eighths inch above the asbestos center of the wire gauze, 
as shown in Figure 2. The support should be iy 2 inches high. 
WIRE GAUZE 
The wire gauze in the bottom of each compartment between the 
flask and the flame should be made of iron wire, from 0.016 to 0.020 
