68 DEPARTMENT BULLETIN 1216, U. S. DEPT. OF AGRICULTURE 
Special marking: "A, S. T. M. loss on heat," a serial number and the manu- 
facturer's name or trade-mark shall be etched on the stem. 
Scale error: The error at any point of the scale, when the thermometer is 
standardized as provided below, shall not exceed 0.5° C. 
Standardization : The thermometer shall be standardized at three points, 
including 103° C, for total immersion. 
Case: The thermometer shall be supplied in a suitable case. on which shall 
appear the marking: "A. S. T. M. loss on bear. 155° to 170° CV* 
Note. — For the purpose of interpreting these specifications the following definitions 
apply : 
The total length is the over-all length of the finished instrument. 
The diameter is that measured with a ring gauge. 
The length of the bulb is the distance from the bottom of the bulb to the beginning 
of the enamel backing. 
The top of the thermometer is the top of the finished instrument. 
4. The container in which the sample is to be tested shall # be of tin. cylindri- 
cal in shape, and shall have a flat bottom. Its inside dimensions shall be 
substantially as follows; Diameter, 55 millimeters (2.17 inches) : depth, 33 
millimeters (1.38 inches). (A 3-ounce Gill-style ointment box. deep pattern, 
fulfills these requirements.) For road oils the container may be a 2-ounce Gill- 
style fiat -bottomed can approximately 60 millimeters in diameter and 20 miUi- 
meters deep. 
PREPARATION OF SAMPLE 
5. The sample as received shall be thoroughly stirred and agitated, warming, 
if necessary, to insure a complete mixture before the portion for analysis is 
removed. 
PROCEDURE 
6. Fifty grams of the water-free material to be tested shall be weighed into 
a tared container conforming to the requirements of section 4. For road oils 
20 grams of material may be used. The oven shall be brought to a temperature 
of 103° C. (325° F.). and the tin box containing the sample placed in one of 
the recesses of the revolving shelf. The thermometer shall be immersed for 
the depth of its bulb in a separate 50-gram sample of the material under test, 
placed in a similar container, and shall be conveniently suspended from the 
vertical shaft. This sample shall rest in one of the recesses upon the same 
shelf and revolve with the sample or samples under test. The oven shall then 
be closed and the shelf rotated five to six revolutions per minute during the 
entire test. The temperature shall be maintained at 163° C. (325° F.) for five 
hours, then the sample shall be removed from the oven, cooled and weighed, and 
the loss due to volatilization calculated. 
7. For a determination of the loss on heating at 100° C. {212° F.) use pro- 
cedure outlined in paragraph '>'. except that the oren is to he maintained at a 
temperature of 100° C. (212° F.). 
8. During the five-hour period the temperature shall not vary more than 1° C. 
All tests showing a greater variation in temperature shall be rejected. 
9. Under ordinary circumstances a number of samples having about the 
same degree of volatility may be tested at the same time. Samples varying 
greatly in volatility should be tested separately. Where extreme accuracy is 
required, not more than one material should be tested at one time, and duplicate 
samples of it should be placed simultaneously in the oven. Such duplicates 
shall check within the limits of accuracy given in section 10. Results obtained 
i i. samples showing evidences of foaming during the test shall be rejected. 
ACCURACY 
10. Up to 5 per cent loss in weight the results obtained may be considered 
as correct within 0.5. Above 5 per cent loss in weight the numerical limit of 
error increases 0.01 for every 0.5 per cent increase in loss by volatilization as 
shown in Table 7. 
