45 
These facts appear very significant, and if some of our mountain-farm- 
ers. will pay some attention to them, they will doubtless find the appli- 
cation of this system of great practical value, and will find in it a means 
of preventing the more valuable constituents of their soils being car- 
ried off by mountain-streams to the valleys below. 
MICROSCOPIC OBSERVATIONS. 
By THomas TaYLor, MICROSCOPIST. 
[Continued from the October Report for 1875, page 445.] 
Several members of the New Jersey Cranberry Association have 
expressed, by letters to this Department, a desire to know whether the 
color of the water on cranberry-plantations can be safely relied on as a 
test of the quality of peat-bottoms. Mr. James Fenwick, of New Lis- 
_bon, one of the most noted cranberry-growers of the State, writes to the 
Commissioner of Agriculture as follows: 
I fear it may be thought by some that the statement which I made at the Cranberry 
Growers’ Association, that the water in my bog was highly colored, and yet for twenty 
years I had never had any rot, was designed to disparage the opinion of the microscop- 
ist of the Department of Agriculture, in regard to that disease; but it was not so 
intended. The association appeared to have the impression that the colored water 
was the cause of the rot; an old idea started by some one who had white water on his 
plantation, to the injury of those who had colored water. I wish to say that the 
labors of the microscopist in this investigation have beeu fully appreciated by me, and 
that personally I am thankful to the Department for them; but believing that the 
cause of the rot in cranberries in our pine region is generally owing to drought and 
high temperature, or flooding with heated or dead water, I am not disposed to change 
my views in this respect, and am still of opinion that his ideas as to the cause of 
the ret in Dr. Merriman’s bog is correct, and that we are indebted to him for it. His 
recommendation to keep the water near the surface in irrigation is reasonable, because 
in drought poisonous substances, consisting of sulphureted hydrogen and organic 
acids, rise from below, and injure the plants. He has advised the use of lime. 
Professor Mapes and many others have recommended lime slacked with salt, which sub- 
stances produce, in the presence of decaying organic matters, furnishing carbonic acid, 
chloride of calcium and carbonate of soda in acheap form. Would not these substances 
be better than limealone? And, in case of irrigation, would not a slow passage of water 
through the soil be preferable to flooding? Thus, suppose two ditches be made two 
rods apart ; let the water be kept in them at a proper height to keep the ground moist, 
say one foot from the surface; put another parallel ditch between them for a feeder, 
and keep the water up to the surface of the soil; then there will be a motion of water 
through the soil toward the ditches on either side. In my judgment, this would be a 
great improvement on the present practice. It would supply moisture to the soil and 
have a tendency to carry off poisonous gases. 
If Mr. Fenwick will review my papers published in the Department 
Monthly Reports for October, 1874, and January and October, 1875, he 
will find that my views are in accord with his as regards the causes which 
operate to produce cranberry-rot. I also consider that his views relat- 
ing to drainage and liming are worthy of experiment, and I hope that 
he will assist in giving an early trial of them, and report the results to 
this Departinent. 
The color of water or bog-land cannot be relied on as a test of the 
quality of peat-muck, inasmuch as color may be derived from a variety 
of causes. Bicarbonate of iron is soluble in water, producing a brown 
color. The coloring-matter of peat is also very soluble in solutions of 
soda, potash, and ammonia, forming deep, brown-colored solutions, and 
the salts of these alkalies have also a slightly soluble effect ; while with 
caustic lime the coloring-matter is precipitated, giving colorless solu- 
