200 BULLETIN OF THE BUSSEY INSTITUTION. 
with pure water, that reacted strongly, both with ammonia, and with 
ammonium oxalate. I am indebted to my assistant, Mr, D. 8. Lewis, for 
this specimen, as well as for the capital idea that dry loams fit to exhibit 
the reaction insisted upon in this article may be found in the cellars and 
attics of most dwelling-houses, stored in old flower-pots. 
VI. Yellow loamy subsoil from the Plain-field. This specimen had been 
kept in barrels in a dry cellar for several years. On being percolated in 
a cylinder of 1,000 cc. capacity, the filtrate from it gave precipitates with 
ammonia water only up to the 100th cc., and the volume of each precipi- 
tate was much less than that of the corresponding precipitate obtained in 
the extract from the surface soil. <A very slight reaction for lime was 
obtained with oxalate of ammonia; no more, indeed, than is given by 
most of the well waters of this vicinity. After percolation, this specimen of 
soil was spread upon a plate, and exposed during four days to pure dry air 
in a glass house that contained no plants, and again percolated; but no 
reaction could now be obtained on adding ammonia to the percolate. 
As would naturally be supposed, the precipitate produced by ammonia 
water varied considerably in appearance and composition, accordingly as 
it was obtained from the percolate of one or another kind of loam. In the 
case of the ashes and the calcined earths, to be mentioned directly, and in 
some of the loams proper, the ammonia precipitate was quite colorless, 
while in some other cases it had a slight yellow tint from the presence of 
organic matter. Indeed, when the precipitate was first met with in one of 
the latter instances, it was not suspected, for the moment, that it was really 
carbonate of lime. As obtained from the percolate from Mr. Beatley’s 
garden earth, there was found. in 0.132 grm. of the dry ammonia precipi- 
tate derived from the first half litre of percolate from eight to ten litres 
of the dry earth, as much carbonic acid as would correspond with 
0.0966 grm. of carbonate of lime, and as much lime as would amount to 
0.0845 grm. of carbonate of lime. In this case, therefore, the ammonia 
precipitate was manifestly almost pure carbonate of lime. But as obtained 
from a similar percolate from Plain-field earth the precipitated carbonate 
was much less pure, —0.03 grm. of dry ammonia precipitate from the 
first half litre of percolate from eight to ten litres of Plain-field earth 
gave as much carbonic acid as would amount to 0.0091 grm. carbonate of 
lime, and as much lime as would amount to 0.0086 grm. carbonate of 
lime. . 
In these experiments, the lime was thrown down as oxalate and 
weighed as quick-lime, and the carbonic acid was set free with an acid, 
collected in soda-lime tubes, and weighed as such. Only an insignificant 
trace of silica was contained in these precipitates in either case. 
It seemed to be evident that the lime-carbonate is held dissolved by a 
slight excess of carbonic acid, and that when the latter is neutralized by 
ammonia, the precipitate, in falling, drags down organic matters. It is 
possible, of course, that the organic matters which were contained in the 
percolates from some of the loams may have helped somewhat to dissolve 
