351 
Chemical votes .—A very fine greenish or yellowish white precipitate. Gives off 
odor of H 2 S when potassium sulphide is added. The proportions were intended to 
he 1 to 2, but by a, mistake 66.60 instead of 66.72, grams were used. Probably the 
compoundis not clearly defined, as the liver of sulphur is a mixture of the trisul- 
phides and pentasulphides, with intermediate forms, but without much doubt Z11S5 
is formed from the peutasulphide of potassium combining with the ZnS0 4 . 
Remarks .—This mixture is more difficult of preparation than ammoniacal solution 
and adheres to the foliage more tenaciously, but was slightly injurious and necessi¬ 
tated dilution to 2 gallons. It proved of scarcely any value in retarding the prog¬ 
ress of the disease. The treated rows were 0 and It grades better than adjacent 
untreated rows on September 2, and 0 and 0 better on October 13. 
Summary .—While none of the above mixtures or solutions were 
really effective in preventing the leaf-blight, the retarding effect which 
several of them had upon the progress of the disease makes it seem 
probable that if their strength be increased they may prove valuable. 
The results of the year’s experiments make possible the following classi¬ 
fication, which will enable the investigator to choose for further exper¬ 
iment those mixtures worthy of trial: 
(1) Mixtures which did not injure the foliage and retarded more or 
less the progress of the disease: Nos. 1. 2, 3, 5, 0, 9, 12, 13. 
(2) Mixtures which injured the foliage, but retarded the progress of 
the disease: Nos. 4, 7, 8, 10, 11, 14, 15, 16, 17, 18, 22, 25. 
(3) Mixtures which injured the foliage and did not retard the prog¬ 
ress of the disease: Nos. 19, 20, 21, 23, 24. 
As will be readily inferred, those mixtures under (3) are plainly ex¬ 
cluded from further trial; those under (2) may possibly prove of value 
if sufficiently diluted, but since they only imperfectly retard the pro¬ 
gress of the disease when strong, they are not likely to be effective 
when of sufficiently weak strength, while those under (1) are worthy 
of further trial in stronger proportions. 
It should be remarked here, however, that these experiments were 
with pear seedlings only, and before making them applicable to other 
plants a trial will be necessary. This is plainly shown in the grape 
experiments with the same mixtures, in which many of the prepara¬ 
tions that were not injurious to pear foliage proved injurious to the 
grape. The results of these experiments will appear elsewhere. 
The writer is most forcibly impressed with the remarkable nature of 
Bordeaux mixture in this respect. Although the trials made by Smiths 
and Powell, of Syracuse, N. Y., with Bordeaux mixture upon seedlings 
were not satisfactory the present season, I am still of the opinion that 
had it been tried upon the experimental plat it would have shown itself 
superior to any of the other preparations employed. So far it seems to 
be the only preparation which gives to the foliage of treated plants an 
appearance of unusual health. 
