8 BULLETIN 529, U. S. DEPARTMENT OE AGRICULTURE. 
investigator, if he is competent, supplies the deficiency in the farmer's 
knowledge of bookkeeping, and together the two of them are able to 
arrive at an approximately correct solution of the problem. 
Similarly with the profits from the entire farm. The farmer knows 
the facts necessary to calculate these profits, even though he may not 
know how to make the calculations. 
It should also be rememembered that the farmer's less accurate 
memory for small details is not a matter of great importance, for 
the smaller the item the less influence an error in it has on the final 
result. 
ACCURACY OF COST-ACCOUNTING METHODS. 
Those having even the most elementary knowledge of the prin- 
ciples of cost accounting are aware that such work always involves 
estimates, no matter how accurately it may be done, and these esti- 
mates not infrequently constitute an important proportion of the 
cost. Consider, for instance, the cost of a day of horse labor. This 
»is the annual cost of keeping the horse divided by the number of days' 
work the horse does in the year. It is possible to arrive at a fairly 
accurate valuation of the feed the horse consumes and of the man 
labor required in caring for the horse, though the latter item itself 
is based partly on estimates (especially of the cost of the man's 
keep). Even then the variation in feeding practice from farm to 
farm and in the eating capacity of individual animals make the 
actual cost of feed a highly variable quantity, so that a single so- 
called " accurate " record is of little, if any, more value than an 
intelligent estimate of an experienced horseman. Another item in 
the cost of keeping the horse is interest on investment. To arrive at 
this we must estimate the market value of the animal. Deprecia- 
tion is also an important element. In arriving at this we must not 
only assume a value for the horse, but we must make a guess at how 
long he will last. Barn rent is another item. To arrive at this we 
must estimate the value of the barn, the length of time it will last, 
the cost of future repairs, and the relative value of the space occu- 
pied by the horse, as compared to that used as a shelter for machin- 
ery, etc. We must also estimate the cost of harness required in 
order that the horse may do its work. The animal must also be 
credited with the value of his manure, another estimate. 
The above facts suffice to show that on the farm even cost account- 
ing is at best largely a matter of estimates. It is merely a question 
of the dependability of the estimates. It has been shown above that 
in matters in which farmers have had extended experience their 
estimates are so sufficiently reliable that when large numbers of them 
are averaged the results possess a very satisfactory degree of accu- 
racy. However, it is not possible to overestimate the importance of 
