f tuberculosis; and (3) the invention of the
hay carrier. It is not the purpose here to discuss barn buildings, but
merely to call attention to the fact that the traditional barn has long
since outlived its usefulness, and that the young farmer should plan
his farm buildings to serve the purposes required in the light of
modern knowledge.

Various attempts have been made to manufacture combined machines; that
is, a machine which, by an interchange of parts or other modification,
may be used for two or more purposes, as, for example, harvesting
small grain and cutting grass. Such attempts have usually been
unsuccessful. On the other hand, the young farmer should consider the
range of usefulness of any given type of machine or tool; thus, a disk
harrow is more efficient for some purposes than a spring-tooth harrow.
For other purposes the spike-tooth harrow is better than the spring
tooth. The spring-tooth harrow, however, will do fairly well wherever
the disk harrow or the spike-tooth harrow is needed. When, therefore,
only one of these tools can be afforded, the spring tooth may be a
better tool to buy than either the disk or the spike-tooth, although
it is not for certain purposes as efficient as either of the others.

The kind of machine should obviously be adjusted to the conditions,
as, for example, the size of the farm, and the character of the
farming. Riding plows may be desirable on level land, but where it is
necessary to plow up and down hill, walking plows should be used. The
extra weight of the wheel plow is not a serious matter on level land,
because the sliding friction has been transferred to rolling friction,
but no mechanical device has been or can be invented which will
decrease the power necessary to raise a given weight a given height.
The various machines requiring horse power should be adjusted, as far
as possible, to require the same number of horses. If the main unit is
three horses, then, as far as possible, all machines should require
three horses, such as plows, harrows, manure spreaders, harvesters,
etc. If the activities of the farm are sufficient to require six
horses then some of the tools may require three horses each, while
others require a pair.

[Illustration: Mr. R. H. Garrahan, Kingston, Pa., is one of the most
successful growers of celery in the United States. After graduating from
the Wyoming Seminary he spent one year studying horticulture at the
Pennsylvania State College. For