BULLETIN OF THE BUSSEY INSTITUTION. 203 
The first trials were made with some of the earth that had been slowly 
calcined, with frequent stirring, in a large iron muffle, at the lowest pos- 
sible temperature, until the last traces of organic matter were destroyed, 
and had then been left to stand for four months in a loosely covered jar. 
On percolating a small quantity of this product, and adding ammonia 
water to the percolate, an immediate and abundant precipitate of carbo- 
nate of lime was obtained, as well as a strong reaction for lime on the 
addition of ammonium oxalate. On reheating some of this earth in an 
iron tube, and then percolating, only a slight ammonia precipitate was 
obtained in one instance, while, in another instance, there was a tolerably 
strong precipitate on adding ammonia. In order to determine how firmly 
the carbonic acid was held by the earth, a small iron tube was charged 
with some of that which had stood for four months after calcination, 
and four litres of hydrogen gas that had been well washed in caustic soda 
were passed through the earth and into lime water; but no reaction for 
carbonic acid was obtained. In order to see what influence, if any, the 
addition of organic matter to the calcined loam might exert, two small 
glass percolators of equal size were charged; one with a 40 x 23 cm. 
column of the old calcined earth, and the other with the same volume of 
this earth with about one-tenth the volume of finely powdered straw. Both 
columns were percolated with pure water, and the percolates were tested 
with ammonia water. But no difference could be detected in the amounts 
of the precipitates obtained, and the precipitation ceased in both cases 
when 100 ce. of percolate had been collected. 
For a second set of experiments, a new portion of the Beatley loam was 
calcined in porcelain dishes in a small iron muffle, with frequent stirring, 
at a somewhat higher temperature than the previous sample had been 
calcined, and the product was tested as follows: Three small equal 
cylinders were charged (1) with the old calcined loam that had stood in 
the air during four months ; (2) with the loam that had been freshly 
calcined; and (3) with some of No. 2 that had been again heated to 
redness in an iron tube, and cooled in a desiccator over quick lime. The 
first 50 cc. of percolate from each tube being taken, and equal portions of 
each sample tested with ammonia water, a precipitate was obtained in 
each case; but, while there was no appreciable difference in the volume of 
the precipitates from Nos. 2 and 3, the precipitate from No. 1 was at 
least twice as large as the others. 
IX. Calcined loam from Mr. Sallonstall’s pasture, as in No. III. 
The experiments on this loam were made several months later than 
those upon the calcined Beatley earth, and for the sake of controlling the 
latter. Two small glass percolators, each with an effective capacity of 
40 x 24 cm., were charged, one with loam from Mr. Saltonstall’s pasture 
that had been calcined two years ago, and been left standing since then 
in a loosely covered jar; and the other with similar loam that had been 
calcined in precisely the same way immediately before the percolation. 
In both instances, the loam was slowly calcined at the lowest possible 
