42 BULLETIN 414, U. S. DEPARTMENT OF AGRICULTT RE. 
account to a cost per capita per day, which is the mam purpose of 
the form, it is necessary that the sum of the actual value of all services 
rendered during a particular period, plus the actual value of supplies 
completely consumed or used during the period, plus the estimated 
depreciation of articles of supply and equipment not completely con- 
sumed during the period, shall be divided by the number of convict 
days for the period. The depreciation of articles not entirely con- 
sumed can be determined only by means of an inventory. But as 
the depreciation of many articles is very slight in a period of a month, 
it is impractical to take the inventory at less than six-month periods. 
In inaugurating the system of accounting, a complete inventory of 
all goods should be taken, and the ascertained value of all supplies 
and equipment of a given class on hand should be placed in a space 
provided at the head of the total column on the proper account form. 
Subsequently, during the first month, all items purchased should be 
reported, giving the names of the items, the dates of purchase, the 
quantities, and their unit and total costs. At the end of the first 
month the total cost of the items purchased should be added to the 
original inventory value to obtain the grand total of value invested 
in the camp at the end of the month. At the beginning of the second 
month the latter figure should be placed at the head of the total 
column. Entries of the items purchased during this month should 
be made as during the first month, and all operations should be simi- 
larly repeated every month. 
When a period of six months or a year has elapsed, the grand total 
of the last monthly report will represent the total amount invested 
in the camp under the given account since the beginning of the period. 
An inventory taken at this time will show the approximate value of 
all articles of supply and equipment remaining in use or in stock, and 
this value deducted from the grand total of the last monthly report 
will give the value of the goods and services consumed or used during 
the period as nearly as can be ascertained. If this value be divided 
by the total number of convict-days for the period, which a proper use 
of the form will show in the upper right-hand corner, the result will 
be the daily per capita cost of supplies and equipment used under the 
given account during the period. This figure, added to the daily per 
capita cost of food for the various months, will give the true cost of 
maintenance per convict per calendar day for each of those months. 
Finally, to obtain the true cost of maintenance per convict per work- 
ing day, this latter value must be modified on account of the time lost 
by Sundays, holidays, camp duty, and sickness, all of which losses 
are reported on the daily reports of construction (No. 8). 
The distribution of charges to the various accounts is largely a 
matter of judgment, but the classification of items given under the 
