ulphur will unite with the lime and burning may be the
result.

This self-boiled mixture is entirely harmless to apple foliage and
even appears to have a stimulating effect upon it. Against the apple
scab, however, it is not as effective as the boiled wash, or the
commercial preparations. For this disease a strength of from one to
thirty to one to forty (that is about one and one-half gallons of the
prepared mixture testing 31 to 33 Beaume to fifty gallons of water) of
the commercial lime-sulphur is most effective.

SPRAY PUMPS.--The application of the foregoing spray mixtures is fully
as important as the sprays themselves, for on the right application at
the right time depends the efficacy of the spray. For this purpose a
considerable amount of special machinery has been devised. Lack of
space prevents us from going into much detail on this question, so we
must be content with merely outlining the different types of machines
and mentioning their accessories. Sprays are forced through single,
double or triple acting pumps, either by hand or power. The three
types of power available are traction, compressed air, and gasoline,
the last being the most used. Steam power is practically obsolete.

The knapsack is the simplest type of hand pump, but it is of no
practical use in the mature apple orchard. For small orchards and
small trees several types of hand pumps are quite effective. The lever
type of pump, where the handle is pushed from and pulled toward the
operator, probably gives the most power with the least tiring effect,
because it enables one to use the weight of the body to some extent.
It is best not to have the pump attached to the spray barrel or tank,
but set on a movable base of its own, as then it can be used for any
one of a number of barrels. Such an outfit may be obtained for from
twenty-five to forty dollars.

It is well to buy a standard make of pump, preferably from a nearby
dealer, so that repairs may be readily secured. For all orchards up to
three or four acres in size, and for larger orchards where the trees
are not over twelve or fifteen feet in height, this kind of spray rig
is the most practicable and advisable, when the expense is taken into
consideration. This applies especially to the general farm.

The power of a traction sprayer is developed from the wheels. There is
much discussion as to whether sufficient power to throw an effective
spray can be supplied by this method. By accumulatin