78 DEPARTMENT BULLETIN 1216, U. S. DEPT. OF AGRICULTURE 
2. Flask. — The distillation flask. Figure 30. shall be a side-neck distilling flask, 
having the following dimensions : 
Millimeters 
Diameter of bulb, outside 86±1. 5 
Diameter of neck, inside 22±1. 
Diameter of tubulature. Inside 10±0. 5 
Length of neck 43±1. 
Distance, top of neck to tubulature 25±1. 
Length of tubulature 220 ± 5. 
Angle of tubulature degrees — 73±1.0 
3. Condenser tube. — The condenser tube shall be a suitable form of tapered 
glass tubing of the following dimensions : 
Outside diameter of small end 12. 5 millimeters ; permissible variational. 5 
Outside diameter of large end . — 28. 5 millimeters; permissible variation ±3. 
Length 360. millimeters ; permissible variation±4. 
Length of tapered part 100. millimeters ; permissible variation ±5. 
4. Shield. — A galvanized-iron shield, lined wtih %-inch asbestos, of the form 
and dimensions showns in Figure 31, shall be used to protect the flask from air 
currents and to prevent radiation. The cover (top) may be of transit board, 
galvanized iron lined with %-inch asbestos, or of other suitable insulating 
material. 
Inside , 
| D/am. I 
ft?mm>\ 
Fig. 30. — Distillation flask 
5. Receiver. — The distillates will be collected in tared Erlenmeyer flasks hav- 
ing a capacity of 50 to 100 milliliters. 
6. Thermometer. — The thermometer shall conform to the following require- 
ments. These specifications cover a total-immersion thermometer graduated 
in either centigrade or Fahrenheit degrees as specified, the range being from 
0° to 400° C. or 30° to 760° F., respectively. 
Type : Etched stem, glass. 
Liquid : Mercury. 
Range and subdivision : 0° to 400° C. in 1° C. or 30° to 760° F. in 2° F. 
Total length: 378 to 384 millimeters (14.88 to 15.12 inches). 
Stem : Plain front, enamel back, suitable thermometer tubing. Diameter, 6 
to 7 millimeters (0.24 to 0.28 inch). 
Bulb : Corning normal or equally suitable thermometric glass. Length. 10 to 
15 millimeters (0.39 to 0.59 inch). Diameter, 5 to 6 millimeters (0.20 to 0.24 
inch). 
Distance to 0° C. or 32° F. line from bottom of bulb: 25 to 35 millimeters 
(0.98 to 1.38 inches). 
Distance to 400° C. or 752° F. line from top of thermometer: 30 to 45 milli- 
meters (1.18 to 1.77 inches). 
Filling above mercury ; Nitrogen gas. 
