202 BULLETIN OF THE BUSSEY INSTITUTION, 
tained saline matters that could account for the solution of the lime- 
carbonate; but no indication of sulphates could be detected, and the 
reaction for chlorides was extremely faint. At no time was the reaction 
so strong as that shown by a solution of chloride of ammonium containing 
0.00002 grm. to the cc.; it became less and less as the percolation pro- 
ceeded, and practically ceased when 300 cc. of percolate had passed 
through the earth. 
The effect of adding more carbonate of lime to the soils than they con- 
tained naturally was tested by mixing some of this substance, in the form 
of whiting, both with Plain-field earth and with sand, and percolating 
the mixtures. As a preliminary to these trials, two samples of whiting 
and one of gypsum were kept in contact with pure water for several days, 
with frequent shaking, then filtered, and the filtrates tested with ammonia 
water. The liquid from one sample of the whiting gave a perceptible 
though slight precipitate with ammonia, while that from the other gave 
scarcely any precipitate. Hence, the second sample was used for the 
experiments that follow. The gypsum solution gave an extremely slight 
precipitate with ammonia water and with lime water. 
A quantity of Plain-field earth was mixed intimately with 1% of 
whiting; the mixture was percolated with pure water, and the perco- 
late was tested with ammonia, in comparison with a percolate obtained 
from the simple earth. The first portions of liquor from the whiting 
mixture gave much stronger reactions with ammonia than those from the 
earth alone; but the reaction gradually diminished in strength for a time, 
and finally became constant. When 1500 ce. of percolate had passed 
through the earth, carbonic-acid water began to be poured upon the top of 
the column, in place of the pure water previously used, and it was noticed 
that 300 cc. of liquor came through before the percolate began to react 
any stronger with ammonia or with lime water than it had reacted before. 
On percolating with pure water a mixture of Plain-field earth and 
1¢%, of gypsum, the ammonia reactions obtained were similar to those 
with the earth alone. 
Berkshire sand, mixed with 1% of whiting and percolated with pure 
water, gave no perceptible reaction with ammonia. 
A series of experiments was next made with earths that had been more 
or less strongly calcined. 
VII. Ashes of anthracite which had been kept five years in barrels in a dry 
store-room. A sample leached with pure water in a large percolator 
yielded a filtrate that gave abundant precipitates of carbonate of lime on 
the addition of ammonia water; and so did another sample tested in a 
small percolator. But on igniting some of the dry ashes strongly in an 
iron tube for half an hour to expel carbonic acid, and testing this ignited 
portion in the small percolator, the first 25 cc. of filtrate gave so slight 
a reaction with ammonia water that the precipitate was barely perceptible. 
VIII. Calcined loam from the garden of Mr. Beatley, as above, No. II. 
