FAHM EXPERIENCE WITH THE TRACTOR. 27 
While qo averages showing the depth of plowing done by horses 
which are entirely comparable with those shown in Tables XVI and 
XVII are available, a comparison of these averages with such averages 
as were available for horse plowing indicates that the difference 
in depth of plowing, if any exists, is rather in favor of the horse. 
The reason for so little deep plowing w T ith the tractor is very evi- 
dent upon a slight examination into the matter. Most tractors are 
incapable of pulling a plow cutting the full width of the tractor and 
turning more than a 6-inch furrow under ordinary conditions. There- 
fore, if deeper plowing is to be done the gang must be decreased in 
width, i. e., one or more plow bottoms must be raised, when the 
gang will no longer cut out the full width of the tractor's track, 
which will probably result in the tractor's wheels passing over the 
same ground twice, causing excessive packing of the soil. 
But the greatest difficulty is that the gang plow which is not as 
wide as the tractor must be hitched to one side of the longitudinal 
center of the machine, in order to permit the drivewheels to travel 
on the unplowed land. Such a hitch not only makes the tractor diffi- 
cult to steer, but exerts a twisting strain on the tractor's frame, 
which is conducive to short life and heavy repair charges. If such a 
plow is hitched to the center of the tractor, one drivewheel must 
travel on the plowed land in order to bring the plow close enough 
to the land side, thus requiring more power to propel the tractor and 
making steering difficult. 
Most tractor owners, therefore, prefer to use a gang plow wide 
enough to permit its being attached to the center of the tractor frame 
and at the same time allow the drivewheels to travel on the unplowed 
land, regulating the depth of the plow by the amount of power 
available. 
PACKING SOIL BY TRACTORS. 
With the early steam tractors the packing of the soil by the trac- 
tor's wheels often caused serious injury to the crop. 
This feature of the early tractor was much advertised and caused 
considerable prejudice in the minds of many farmers against all 
tractors, both gas and steam. 
While some gas tractors, under certain conditions, have injured 
the crop by packing the soil, this is not ordinarily the case. The 
answers of 135 tractor owners who were personally interrogated 
on this point have been compiled. These men were located in various 
States in the Northwest. In answer to the question ' ' Does the packing 
of the soil by tractor wheels injure the crop V only 9 men state that 
the packing of the soil is injurious, while 101 say that it is not, 22 
of this number declaring it to be beneficial. Of the 135 owners 
answering, 25 replied: "If the soil is wet, yes; if dry, no." 
