386 BULLETIN OF THE BUSSEY INSTITUTION. 
the experiments cited by Mr. Colman, in his “ Fourth Report of the 
Agriculture of Massachusetts,” Boston, 1841, pp. 824-339. 
VI. A sample of the so-called “ Slurry” of the flint-glass makers, 
obtained from the works of the New England Glass Company at East 
Cambridge in the spring of 1875. 
In order to avoid all risk of impurity in the carbonate of potash used 
for making the better kinds of glass, it is customary in this country to 
purify pearlash at the glass works. In the process of purification the 
less soluble part of the pearlash is excluded as a waste product, which 
consists of sulphate of potash for the most part, and which may be 
obtained at glass works, as the so-called slurry. This slurry is a fine 
white powder, or rather salve, for the powder being saturated with 
‘mother-liquor that contains carbonate of potash is thereby made moist, 
slimy, and coherent. The slurry is of interest to the farmer, since it 
offers him one source of high-grade sulphate of potash. It has in fact 
long been used as such by the manufacturers of alum. That it is a 
powerful manure of special value upon our poor New England soils 
was shown long ago by the field experiments of Mr. Deming Jarves 
and others, at Sandwich, reported by Mr. Colman, in his “ Fourth 
Report of the Agriculture of Massachusetts,” Boston, 1841, pp. 344, 
345. Mr. Jarves insists upon the importance of mixing the material 
thoroughly with earth before applying it to the land, since from its 
unctuous character it is apt to lie in lumps, and do more harm than 
good. He used ten horse-cart loads of loam for each barrel of the 
slurry. The sample in question, which was actually wet and undrained, 
contained, — 
Moisture . 2 5 1 + 6 5s 8 ee + ss 
MLE AOI eee Pre ed ee ee ee eee 27 
Sulphuric ‘acid ise) RA ay OST. le 
Real-potash (K,O) 3) wh cuisil sb ee iy Se 
Phosphoric acid «is 1s sas Laliceos 48. 50 
Or, in terms of saline combinations : — 
Sulphate of potash. . . . . . . + « + . 66.53% 
Carbonate of potash =... 4. ss os si us ts 
The sample contained some chlorine and a little lime and alumina, 
but no soda, or as good as none; on testing it with a standard acid 
there was found as much alkali as would amount to 12.82%, in terms 
of pure dry carbonate of potash. 
