FARM EXPERIENCE WITH THE TRACTOR. 33 
eyery 12 acres can not hope to produce crops as cheaply as his neighbor 
with a 1,400-acre farm who has an invested capital of only $4 per 
acre and who tills 32 acres with each unit of power. 
It is not surprising, therefore, that the owners of farms containing 
640 acres or less do considerably more custom work than those with 
larger farms, as the excess power must produce some income in order 
to justify its maintenance. 
In this connection, it should also be noted that the repairs per acre 
are considerably less for the large farms than for the small ones, which 
naturally follows, in view of the difference in equipment. It is 
probable that the repairs bear a closer relation to the size of the engine 
than to the size of the farm, in view of the slight difference in the 
number of days used. 
USE OF TRACTORS AT NIGHT. 
The number of men who used their tractors at night was found to be 
surprisingly small (about 11 per cent in North Dakota and 14 per 
cent in other States) and in most cases the number of nights used per 
year was comparatively insignificant. While the tractor is theoreti- 
cally capable of working night and day, it appears that night work 
is seldom done. 
The explanation of this probably lies in the fact that in normal 
years there is little need for operating at night, unless it be during 
harvest, when it may be. desirable to rush the work as much as possi- 
ble in order to prevent loss from storms. However, tractors are not 
extensively used for harvesting except in those sections where it is 
practicable to use a combined harvester. Another reason for the 
small amount of night wx>rk is the necessity of having two operating 
crews for the outfit. This is obviously impractical in most cases. 
In order to ascertain whether any loss of efficiency occurs when 
operating at night, a number of tractor owners who had operated at 
night w r ere asked for estimates as to the percentage of efficiency 
compared with work done in the daytime. The average of these 
estimates was 93.3 per cent. 
This slight loss in efficiency appears to be due almost entirely to 
inability to watch the operation of the outfit as well as it can be done 
during the day and the additional time required to make any adjust- 
ments which may be necessary. 
Among some 70 men who w r ere interrogated regarding night work 
the opinion was almost unanimous that the motor developed more 
power at night than during the day, some estimating the increase to 
be as much as 20 per cent. 1 
i This information was voluntary, the men having been asked simply for an estimate as to the efficiency 
of the tractor at night. They offered their observations as to the increase of power at night as a phenomenon 
which they could not explain. In view of the varying opinions of gas-engine experts on this point, the 
unanimous observation of tractor operators that such an increase does occur is of interest. 
