BULLETIN OF THE BUSSEY INSTITUTION. 199 
but no satisfactory results were obtained, on account of the extreme dilu- 
tion of the lime solution, and I have not yet found time to return to the 
study of this question. 
It is plain, from the foregoing statements, that the absolute amount of 
carbonate of lime and of carbonic acid contained in the percolates from 
dry loams are extremely small; but it is none the less true that super- 
carbonate of lime is a very prominent constituent of these percolates, as 
it is the purpose of this paper to insist. It may here be said that the 
amount of this substance found in the percolates from the dry loams 
examined in this laboratory is very much larger than that contained in the 
waters of several wells in the immediate vicinity of the Bussey Institution 
which have been tested at sundry times. 
Il. Dry loam from the garden of Mr. R. Beatley, Chelsea, Mass. 
1000 grms. of the earth were placed in a smaller percolator than the fore- 
going, and treated with pure water. Fractions of the percolate of 50 cc. 
each were tested with ammonia water as before. Up to 400 cc., the pre- 
cipitate was flocculent, and settled readily; afterwards, it was milky, and 
settled with difficulty. The percolation was continued until 1,000 ce. of 
liquid had passed through the earth, and the reaction with ammonia was 
very nearly or quite as decided in the last fraction as it had been at the 
400th cc. Between the 400th and the 1,000th cc., the reaction with am- 
monia was still sufficient to give a very decided milkiness to the liquid; 
enough, for example, to render opaque the contents of a test tube 20 mm. 
in diameter. It would evidently have been an exceedingly wearisome 
matter to wash out the whole of the lime-carbonate from this earth by 
means of water. 
Ill. Dry loam from an old pasture on the farm of Henry Saltonstall, Esq., 
Lynnfield, Mass. 1,000 grms. of the earth were percolated and tested, as 
in No. II. A flocculent precipitate was obtained in each fraction, on 
adding ammonia water, up to 550 cc., though the precipitate was faint in 
the last fractions. A very slight, hardly perceptible, cloudiness was ob- 
tained in the next fraction, but none afterward. On leaving the contents 
of the percolator to stand over night, and then pouring fresh water upon 
them, the first portions of the filtrate again gave a slight milkiness on 
being tested with ammonia. It was noteworthy, in this instance, that 
reactions for carbonic acid, as obtained by distilling the vapor of the 
acidified percolate into lime water, were got long after the fractions had 
ceased to react with ammonia water. The percolate gave a strong reac- 
tion for lime, when tested with ammonium oxalate, in one of the early 
fractions. 
IV. Dry peat from the Bussey Farm. 1,000 cc. were percolated with pure 
water, and the filtrate tested as before. 450 cc. of the water were held by 
the peat before drops of percolate began to fall. Slight precipitates were 
obtained with ammonia water and with lime water. 
V. Dry earth from an earthen flower-pot, that had been standing for some’ 
months out of use in a dwelling-house at Rochester, Mass., gave a percolate 
