I 
22 The Coeorado Experiment Station. 
the arsenic into solution, even when it is present as lead arsenate. 
It has often been asked at meetings of these orchardists whether it 
was a safe practice to use their surface alkali water in applying the 
lead arsenate and'I have stated that it was not a good practice, for 
one could easily conceive of conditions under which the whole 
of the lead arsenate could be converted into sulfate of lead and 
sodic arsenate be formed in the solution. This statement never 
seemed to be an acceptable one. I have in this case not depended 
upon any chemical laws, however, evident their adequacy might be, 
but took well washed lead arsenate, a sample which we found by 
rigid test to be free from soluble arsenic, suspended one gram of it 
in 2,000 times its weight of water and added two grams of Glauber’s 
salt, allowed it to stand three days, filtered off a portion of it, con¬ 
centrated by evaporation and tested it for arsenic. I found that the 
arsenic had gone* into solution in very considerable quantities. A 
parallel experiment was carried out with salt in which only one gram 
of salt was used to the 2,000 grams of water. This was not allowed 
to stand quite three days when 1,500 grams were filtered off, con¬ 
centrated and tested for arsenic. This concentrated solution was 
found to be so heavily charged with arsenic, that only a small part 
of it gave an unmanageable amount of arsenic when brought into an 
active Marsh apparatus. 
A similar series of experiments was made with the lime ar- 
senite. We included in this experiment the salts above mentioned 
and also distilled water; the lime arsenite was prepared by pre¬ 
cipitating a solution of calcic chlorid containing an excess of the 
lime salt with a solution of arsenite of soda, filtering and washing 
it. This precipitate was probably the pure normal arsenite of lime. 
One gram of this lime arsenite was suspended in 2,000 times its 
weight of distilled water, another gram in a like quantity of water 
containing two grams of Glauber’s salt and a third gram in a like 
quantity of water to which had been added one gram of salt. The 
calcic arsenite seemed almost completely soluble in each of the three 
trials. 
We have then direct proof that the alkali salts in the soil are 
capable of bringing the arsenic, even when present as arsenate of 
lead, into solution and consequently making it a source of danger. 
In regard to the arsenite of lime, there would seem to be but 
little to be said. I remember having years ago tested the clear so¬ 
lution remaining after the lime and arsenite of lime had settled and 
as I now recall it, for I have no note on it, the solution was free 
from arsenic. If this is correct it may have been due to the great 
excess of lime present. 
TIME salts in the soil DO NOT PREVENT THE SOLUTION OE ARSENIC 
The idea expressed in the last sentence has persistently pre¬ 
sented itself in another form, namely would not the lime salts oc- 
