8 BULLETIN 1002, U. S. DEPARTMENT OF AGRICULTURE. 
In very large cities, on the other hand, an" active demand for open 
markets may exist in the congested sections, but the furnishing of 
•the necessary supplies to such sections may be impracticable. Open 
farmers' markets are thus out of the question in certain sections of 
very large cities, because the areas of production are so far from 
those sections that it is unremunerative for farmers to haul their 
wares there. If such sections are to be provided with open markets, 
they must be markets of hucksters and pushcart vendors. It may be 
mentioned in passing that such congested sections of cities as those 
referred to above are often admirable locations for inclosed middle- 
man markets. 
Exceptions will exist, but in general even the simplest type of 
open retail market along a street curb can not be expected to succeed 
in towns of less than 10,000 to 12,000 population. It will usually 
be unwise to establish a substantial open retail market on a market 
tract in cities of less than 25,000 or 30,000 population unless the 
signal success of a curb market demonstrates that the situation is 
exceptionally favorable. Wholesale markets, even when combined 
with retail markets, are seldom found in cities of less than 40.000 
population unless they are maintained largely for sales to outside 
buyers for shipment. The best developed wholesale markets are 
found in cities of well over 50,000 population, and it is also in the 
cities from this size upward that the most thriving open retail 
markets are found. 
The size of a city alone, however, is only a rough indication of the 
practicability of establishing a certain type of market. A more accu- 
rate index is the probable number of people who can be depended 
upon to patronize the market. The proportion of a population which 
represents potential market customers will vary with nationality, 
local customs and prejudices, climatic conditions, and the like. It 
often happens, therefore, that a public market in one city receives 
heavier patronage than a similar market in a somewhat larger city. 
In estimating the number of potential customers of a public market 
consideration must be given also to existing agencies such as " green 
groceries," hucksters, and other agencies concerned in the distribution 
of farm products, and to what extent such agencies meet the needs 
of consumers. 
Of equally fundamental importance with the subject of demand in 
determining the practicability of a public market is the matter of the 
supply and potential supply of products to be handled in the market. 
Obviously these two essential factors — demand and supply — must be 
in proper relationship before a successful market can be created. 
Open markets have to do primarily with supplies of produce origi- 
nating within hauling distance. Where little or no good farming land 
