304 BULLETIN OF THE BUSSEY INSTITUTION. 
they gave convincing evidence as to the limitations of the process. 
They show clearly enough that while this method of assay can 
readily distinguish a true garden soil, like the specimen from Mr. 
Beatley,* from the mediocre loams with which it was contrasted, 
it is incapable of making definite practical distinction between 
ordinary loams taken from fields and pastures here in Massachu- 
setts. Indeed, as will be seen from the table, the loam from the 
‘* exhausted ” Bean-plot gave rather better results than were 
obtained from the original Plain-field loam, and the loam from 
Mr. Saltonstall. This result may be due, of course, to changes 
in the composition of the loams brought about in the process of 
calcination, but the fact remains that the method of assay is 
incompetent to distinguish poor loams from those which are some- 
what poorer. All this, quite beside the great practical difficulty of 
carrying out this kind of experiments, which require devotion of a 
peculiar order. As a general rule three months elapsed between the 
sowing and harvesting of my buckwheat crops, during which inter- 
val incessant care and watchfulness had to be exercised in order 
that the plants should be kept properly warm, properly cool, and 
sufficiently moist. The experiments would be ruined in case any 
carelessness should occur, in respect to either of these conditions, 
at any moment during the three months. I have been extremely 
fortunate throughout the experiments, both in the faithfulness of 
my helpers and in the absence of damage to the glass house from 
falling ice and snow. On only two occasions have any real disas- 
ters been met with: once in the beginning, when a spell of hot 
weather in early summer destroyed a house full of plants, and 
taught the lesson that work of this sort in a glass house must in 
this particular locality be limited to the cooler season; and once, 
when a single mouse got into the house for one night in January 
at a time when more than a hundred plants were just ready to be 
harvested. As luck would have it, the animal ate some seeds 
here and others there in such manner that utter doubt and un- 
certainty was cast upon the whole collection of crops, and the 
three months’ work had to be done over again in another year. 
Of course, if the method of assay had succeeded, as was origi- 
nally hoped, practical tests with it would naturally have been 
conducted in ordinary greenhouses where the usual care of the 
* Analysis of the original (uncalcined) loam from Mr. Beatley showed 
that it contains 1.92% of potash (K,O); 2.57% of lime (CaO) and 0.40% of 
phosphoric acid (P,0;). 
