20 BULLETIN 973, U. S. DEPAETMEXT OF AGRICULTURE. 
A wide variation in efficiency is also shown where the same method 
of washing is nsed. There are many factors that cause these varia- 
tions, as, for example, some of the machines of the same type are 
more serviceable and of a larger capacity than others; also, the 
operators are delayed from time to time by numerous unavoidable 
causes, such as breakdowns, broken bottles, or lack of steam, but 
the greatest factor in causing these variations is the arrangement 
of the plant. The management and handling of labor are also 
important factors. 
COMPARISON OF COSTS IN WASHING BOTTLES. 
Using the data in Table 7 as to number of bottles washed per man- 
hour, it is possible to make a comparison of costs in washing bottles 
by the various methods for plants of various sizes. According to 
this table the average number of bottles washed per man-hour at 56 
plants using one automatic washer each was 1,002; at 49 plants 
using brush washers, 323 : and at 8 plants washing with a hand brush, 
199. Assuming that labor is worth 50 cents an horn', which is about 
the average at these plants at the present time (1922), the labor cost 
per 100 bottles washed would be 4.99 cents. 15.48 cents, and 25.13 
cents for the three methods respectively. The capacity of the auto- 
matic washer used at the various plants varied considerably, of 
course, but a fair estimate of the present average purchase price of the 
automatic machines used at all the plants is S3, 500. 6 For the brush 
washer the average current price (1922) for the particular types used 
would be about S400. Assuming that the depreciation and other 
annual expense on the bottle washers is 20 per cent of their purchase 
price, this charge would amount to SI. 92 a day for the automatic ma- 
chine, and $0.22 a day for the brush washer. In the case of hand wash- 
ing this extra charge would not be worth considering. Using these 
averages for labor cost and for interest and depreciation on the ma- 
chines. Figure 15 was worked out to show the relative costs for labor 
and interest and depreciation on the equipment of the various meth- 
ods for plants washing different numbers of bottles daily. The cost 
per bottle is shown in the left-hand margin, while the number of bot- 
tles to be washed is shown in the bottom margin. 
Hand washing is represented by a straight line, as the labor cost 
would be the same per bottle, regardless of the number washed, and 
no charge for interest and depreciation is considered. The line show- 
ing the cost with the brush washer crosses that representing the cost 
with the automatic machine at about 1,600 bottles, indicating that 
when this or any larger number of bottles is to be washed it would be 
advisable to consider the economy of installing an automatic washer. 
The high wages that have to be paid for labor in the plant have an 
important bearing on this question. The hand-washing system is 
out of the question for any plant at present prices (1922) of labor 
and the brush washer is economical only at very small plants. 
A similar graph was worked out to represent conditions in 1914 
previous to the present high prices for labor and equipment. This is 
shown in Figure 16. The labor costs used were the average for 40 
plants using automatic washers, 43 plants using brush washers, and 8 
plants where the bottles were washed by hand. The average number 
6 Such plants should also have a brush washer to take care of the very dirty bottles. Such a brush would 
add slightly to the total cost. 
