


BULLETIN No. 897 
Coniributien from the Bureau of Chemistry 
CARL L. ALSBERG, Chief 


Washington, D. C. PROFESSIONAL PAPER November 15, 1920 

WEIGHT VARIATION OF PACKAGE FOODS. 
By H. RuNKEL, Assistant Chemist. 
CONTENTS. 
Page. Page. 
Introduction. ..........-.+-----+----- 22+ 2222+ 1 | Comparison of calculated results with observed 
Methods of weighing.............-.--------.- SE TOSI G See eee te! 2 yi ee ae i 
Good commercial practice ofhand weighing.... 2 | Hand we‘ghing versus machine weighing...... 13 
Calculated maximum errors of good commercial Practical application of experimentalresults... 19 
practice. ......-...---------22--- eee sees AS Pe Sum MAryse ene ieee ce) ee eee a et IA 20 
Experiments on good commercial practice 
IMOLMOUS ees sha sae ea icio esa cie eee Se eee 10 | 
INTRODUCTION. 
The food official and the food packer often ask, ‘What is the 
Variation in weight of package foods?’’ The answer might be 
simple when only a particular product packed at a particular factory 
is considered, but the complex manipulations in packing and the range 
of supervision employed at different factories make any answer sub- 
ject to qualifications when applied to an entire industry such as the 
packing of spices, coffee, sugar, rice, and similar free-flowing sub- 
stances. The establishments which pack these products, however, 
have some methods of manipulation in common, which, when given 
reasonably adequate supervision, result in a fairly definite range of 
variation in weight. It is recognized that an answer might be ob- 
tained by different methods, but the steps by which an answer has 
been reached in this bulletin are (1) selecting specifications for a 
methed of weighing to represent good commercial practice in pack- 
aging granular, free-flowing products, (2) calculating the maximum 
errors expected from these specifications, and (3) showing that the 
calculated errors approximate the variations in weight found by the 
commercial application of the specified method. 
In accordance with the phraseology of the theory of errors which 
has been employed in the calculations, variations from the intended 
weight are called ‘‘errors.”’ 

1 Acknowledgment is made to J. C. Munch, of the Bureau of Chemistry, for assistance in the collection 
and compilation of the data, and to the various members of the field force of the Bureau of Chemistry who 
assisted in the collection of information from varicus factories. 
425°—20—Bull. 897——1 
