24 
Upon the same basis as before, 3 ounces of copper carbonate will yield 
1.5 ounces of basic carbonate and 1.32 ounces of cupric hydroxide, 
or a total of 2.82 ounces. The difference between the modified eau 
celeste and the ammouiated copper carbonate consists in the presence 
of sodium sulphate in the former material, and its absence in the latter. 
Whether this sodium sulphate will be at all harmful to foliage is a ques¬ 
tion to be decided by experiment, and the writer would advise that this 
question be tested. The cost of the copper carbonate in the modified 
eau celeste is approximately 20 cents per pound, while the cost of the 
commercial carbonate, is, according to present quotations, 65 cents per 
pound. Furthermore it is seen from the following table that the cost 
of the basic salts of copper deposited upon the plant, is, in the modified 
eau celeste, 29 cents per pound, and in the ammoniacal copper carbon¬ 
ate 94 cents per pound ; a difference worthy of serious consideration. 
In the use of both the modified eau celeste and the ammoniacal cop¬ 
per carbonate there is not produced continually a basic carbonate of 
copper, but a mixture of the basic carbonate, and the hydroxide. Would 
it not therefore be well to try the pure basic carbonate either by pre¬ 
cipitating the copper with sodium carbonate, and applying it in suspen¬ 
sion as the hydroxide is applied in the Bordeaux mixture or by dissolv¬ 
ing this precipitate in ammonium carbonate ? By the former method, 
using 2 pounds of copper sulphate, and 2J pounds of sodium carbon¬ 
ate, we would have an extremely cheap and x^erhaps effective fungicide. 
The following table has been constructed that the facts contained in 
this x>aper might be presented in a condensed form. 
The writer in conclusion would x^articularly recommend that the rela¬ 
tive value of the hydroxide, the basic sulphate, and the basic carbonate 
be tested by the application of materials containing equal weights of 
these salts x>er unit of water. 
Name of fungicide. 
Form of salts when dry upon 
the plant. 
Weight 
of fore¬ 
going 
salts per 
22 
gallons. 
Weight of 
original 
copper salt 
to make 1 
pound of 
salt when 
dry 
on plant. 
*Cost of 
fungi¬ 
cides per 
22 
gallons. 
Cost of 
lpound 
of copper 
salt when 
dry 
on plant. 
Bordeaux mixture. 
Pounds. 
Pounds. 
Cents. 
Cupric hydroxide, Cu(OH )2 _ 
2. 34 
2.5 
34. 25 
*0.146 
Eau celeste. 
Basic copper sulphate, Cu SO4, 
2Cu(OH) 2 . 
.47 
2.13 
21.25 
. 452 
Modified eau celeste .... 
Basic copper carbonate, C 11 C0 3 , 
Cu(OH) 2 , and Cupric hydrox¬ 
ide, Cu(OH) 2 . 
.82 
Ounces. 
2. 44 
24.37 
.297 
Ammoniacal copper car¬ 
bonate. 
Basic copper carbonate,CuC0 3 , 
Cu(OH) 2 , and Cupric hydrox¬ 
ide, Cu(OH) 2 . 
2.82 
1.06 
16.6 
.942 
* Wholesale eostol materials from which calculations in the last two columns of the above table were 
made: Copper sulphate, 5$ cents per pound; sal soda, 1£ cents per pound; strong ammonia (26°), 7 cents 
per pound ; copper carbonate precipitated from copper sulphate by sal soda, 13.87 cents per pound. 
Delaware College, Newark, Del. 
