FARM MANAGEMENT PRACTICE OF CHESTER COUNTY, PA. Bl 
add materially to the profits of the farm business, while if the enter- 
prise be made either smaller or larger than this the profits are 
reduced. Generally speaking, the farmers in the older settled agri- 
cultural sections have arrived at this optimum magnitude for the 
various enterprises they maintain on. their farms. But they have 
done this in response to the action of obscure economic ferces which 
are not clearly perceived. Hence many of them make mistakes in 
the matter of the relative magnitude of the enterprises they main- 
tain. One of the most important lessons to be learned from a study 
of the kind reported in this bulletin is the position each enterprise 
should occupy on the farms of a given locality for best results. Jn 
order to be able to determine this point, however, it is necessary that 
the survey include a large number of farms, and that these farms 
may be separable into large groups in which approximately the same 
mixture of farm enterprises occurs on all the farms within the same 
group. 
- The adjusted labor income, of which use is made in the following 
tabulations, has already been explained. (See footnote, p. 25.) It 
has been calculated in such a way as to eliminate, as far as possible, 
the effect of magnitude of business on the labor income. Within a 
given region magnitude of business probably has more influence in 
determining the profit made by the farmer than any other one factor. 
In order to study the influence of less important factors satisfactorily. 
it is therefore desirable to eliminate this one. It would also be highly 
desirable to eliminate the factors of yields of crops per acre and 
income per animal unit, which are the next most important in study- 
ing such minor factors as percentage area of each crop, percentage 
of income from each enterprise, etc., but the number of farms avail- 
able for this study is not large enough to permit this. 
In some of the tabulations it will be seen that a relatively slight 
change in the percentage area of a given crop, or in the percentage of 
income from a given enterprise, appears to make a very decided dif- 
ference in the profits made by the farmer. In some cases this differ- 
ence is too great to be accounted for merely by the difference in 
crop area or in percentage income under consideration. This is 
particularly true in the case of the relation between percentage of 
income from fruit and labor income. (Seep. 40.) A very slight 
increase in percentage of income from fruit amounting to less than 
1 per cent of the total amount of income from these farms is accom- 
panied by an increase of 18 per cent in the average labor incomes. 
The reason for this is probably not because of the additional 
profits secured from the sale of fruit, but because in the main it is 
only the better class of farmers who take any care of their fruit 
and who go to the trouble to market the small surplus of this com- 
