382 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
of preparations containing sulphate of copper we will be able to prevent, or at least 
to greatly diminish, the ravages of one of the worst enemies of the American farmer. 
Directions for the preparation and application of the remedies thought most hkely 
to prove successful are here presented, and it is earnestly recommended that they be 
given a thorough trial in order to demonstrate their supposed value. : 
LIQUIDS. 
(1) Eau celeste, blue water, (the ‘‘Audoynaud process”).—Dissolve 1 pound of 
sulphate of copper in 3 or 4 gallons of warm water; when completely dissolved and 
the water has cooled, add 14 pints of commercial liquid ammonia, then dilute to 22 
gallons. The concentrated liquid should be kept in a keg or some wooden vessel 
and diluted when required for use. Apply in clear weather with a suitable force- 
pump having a fine spraying nozzle, which will spray the plants thoroughly but 
not drench them. Make the first application when the plants are in bloom, the 
second a week or ten days later, and if the weather be such as will favor the devel- 
opment of ‘‘ rot,” a third, and perhaps a fourth application should follow within 
about the same intervals. ; 
(2) Copper mixture of Gironde, Bordeaux mixtwre.—Dissolve 4 pounds of sulphate 
of copper in 16 gallons of water ; in another vessel slake 4 pounds of lime in 6 gal- 
lons of water. When the latter mixture has cooled, it is slowly poured into the 
copper solution, care being taken to mix the fiuids thoroughly by constant stirring. 
It is well to have this compound prepared some days before it is required for use. 
(The ee of copper ought to be purchased in a powdered state, as it dissolves 
with difficulty in the ordinary crystalline form.) 
This liquid, slightly thickened because of the lime, may be applied with small 
brooms or wisps made of slender twigs, which are dipped into the compound and 
then switched over the plants so as to thoroughly spray the leaves. This method 
is wasteful and tedious, however, and where one has a considerable area to cover it 
would be economy to procure a spraying pump; the essential features of a good ma- 
chine are ease and rapidity of application with economy of material. 
‘i Follow the same general directions in making the applications as are given under 
Yo. 1. 
POWDERS. 
(3) Sulphatine (the Estéve process).—Mix 2 pounds of anhydrous sulphate of cop- 
per with 20 pounds of flowers of sulphur and 10 pounds of air-slaked hme. : 
(4) Blight powder.—Mix 3 pounds of anhydrous sulphate of copper with 87 pounds 
of flowers of sulphur. 
This amount will be sufticient for one application to 5 acres of potato plants. 
Powders possess the advantage over the liquid remedies of requiring less labor in 
transportation and of being more easy of application, consequently they will be 
preferred to the liquids, should they prove equally efficacious. 
For applying the powders, which ought to be done when there is no wind and 
when the leaves are wet with dew or rain, the primitive arrangement, made of tin 
and constructed like a large pepper-box, or rather like aninvertedfunnel with fine 
wire gauze fastened over the lower end, and which, when filled with the powder, 
is held over the plants and shaken, is efficient and at the same time simple and in- 
expensive. Only enough of the powders, especially of the sulphatine, should be 
applied to be simply visible upon the leaves, as heavy doses may burn them. ; 
Owing to the continual motion of the leaves of potato and tomato plants, by which 
both surfaces are liable to receive the spores of the fungus, the applications ought to 
cover both sides; this can best be accomplished by the use of a bellows with an 
extension nozzle, enabling the operator to direct the blast. 
The degree of success attending the use of these compounds will depend more ar 
less (1)-upon their careful preparation, (2) the time of applicatioh, (8) the more or 
less intelligent manner in which they are applied, (4) the atmospheric condition ex- 
isting at the time or which may follow the applications, (5) the number of treat- 
ments made, and (6) the purity of the lime and sulphate of copper used. 
The following observations are essentially the same as those recently published 
by the French minister of agriculture, in a circular of similar import to this. 
The experiments should be conducted in such a manner that the vines cr plants 
treated and those left untreated (to serve as control experiments) may be compara- 
ble; they ought to be of the same variety, cultivated at the same time, and in all re- 
spects alike. The digging of the treated and untreated plants ought to be made 
simultaneously, for it has been proven that the tubers may be infected at the mo- 
ment when they are taken from the ground, and that the chances of infection are 
