2 BULLETIN 1009, TJ. S. DEPARTMENT OF AGRICULTURE. 
Because the Net Weight Amendment to the Federal Food and 
Drugs Act and many State laws require that food in package form 
bear a statement of the quantity of contents, the obligation of the 
food official to the consumer includes the promotion of the delivery 
of bottles of food which vary as little as possible from the stated 
quantity of contents when the possibilities of good commercial prac- 
tice are taken into consideration. The obligation of the bottler to 
the consumer calls for an effort to deliver bottled food products, 
such as flavoring extracts, mineral waters, carbonated and uncar- 
bonated beverages, molasses, honey, maple sirup, vinegar, olive oil, 
essential oils, table oils, catsup, and salad dressing, which are as 
uniform in quantity of contents as is commercially practicable. The 
bottle manufacturer, therefore, is under direct obligation to the 
bottler and indirect obligation to the consumer to furnish bottles 
which are as uniform in capacity as it is commercially possible to 
make them. 
It is the purpose of this bulletin to describe a commercial method 
of bottling which may be considered " good," to calculate maximum 
variations in the volume of bottled liquids used as foods when packed 
in accordance with specified good commercial practice, and to present 
data showing that the calculated maximum variations of the good 
commercial practice outlined can be met by the bottler. 
The results of the investigation here reported are intended to be 
applicable to liquid foods only. 
SOME CAUSES OF VARIATION IN VOLUME OF FOOD IN BOTTLES. 
The variation x of the quantity of food in the bottle depends on 
many factors, since various types of bottles are manufactured by 
various methods and filled by various methods. The causes of the 
variations are cumulative, extending far back into the history of the 
bottle. In order to direct attention to the relative weight of some of 
the causes, certain pertinent factors in bottle* manufacturing, 
methods of bottling, and types of bottles used as food containers 
are mentioned 
BOTTLE MANUFACTURE. 
Bottles are manufactured by three processes : Hand, semiauto- 
matic machine, and automatic machine. The processes yhtj in two 
particulars — first, the method of gathering the proper amount of 
glass to be blown into a bottle, and, second, the method of blowing 
the bottle. 
Hand blowing is the oldest and simplest method of manufacture. 
In this process one end of the punty, a hollow tube about 6 feet 
long, is inserted in the molten glass and rotated until the amount of 
glass necessary to produce a bottle of the desired weight has been 
