“4 
commen 
Vesontite rtm tt 
Economical Geology of Massachusetts. 371 
They show us the amount of nutriment in the soils of Massachusetts ; also how 
much of it is in a fit state to be absorbed by plants, and how much of it will need 
further preparation. As this is probably the first attempt that has b de to ob 
tain the amount of geine in any considerable number of soils, we cannot compare 
the results with those obtained in other places. They will be convenient, however, 
for comparison with future analyses; and we learn from them, that geine, in both 
its forms, abounds in the soils of the state, and that it most abounds where most 
attention has been paid to cultivation. It ought to be recollected, that I took care 
not to select the richest or the poorest portions of our soils; so that the geine in 
this table is probably about the average quantity. It is hardly probable that the 
number of specimens analysed from the different varieties of our soils is sufficiently 
large to enable us to form a very decided opinion as to their comparative fertility, 
in som 
especially when we recollect how much more thorough is the cultivation 
arts of the state than in others. It may be well, however, to state the average 
quantity of geine in the different geological varieties of our soils, which is as 
follows ; 
Soluble Geine. Insoluble Geine, 
lluvium, 2.25 - ere cet 
Tertiary argillaceous soils, oo ee eo 
Sandstone do. 3.28 - - - - 2.14 
Gray wacke do. $3.60, <5 -= - - 4.00 
Argillaceous slate do. 5.77 - - - - 4.53 
Limestone do. 3.40 - - - - 4.04 
Mica slate do. 4.34 - - - - 4.60 
Talcose slate do. 3.67 “ - * * 4.60 
Gneiss do. AD nae se 
Granite do 4.05 + . . * 3.87 
Sienite do. 4.40 ety ae . - 4.50 
Porphyry do. G97. ae et ee 
Greenstone . do C56 ss - - - 6.10 
One fact observable in the above results may throw doubts over the fundamen- 
tal principles that have been advanced respecting geine ; viz. that it constitutes the 
od of plants, and that they cannot flourish without it. It appears that our best 
alluvial soils contain less geine, in both its forms, than any other variety, except 
those very sandy ones that are not noticed in the above results, because their num- 
is so small. Ought we hence to infer that alluvium is a poor soil? I appre- _ 
hend that we can infer nothing from this fact against alluvial soils, pt that they 
are sooner exhausted than others, without constant supplies of g For if a soil 
contain enough of this substance abundantly to supply a crop that is growing upon 
it, that crop may be large although there is not enough geine to ki 
Now analysis shows that our alluvial soils contain enough of g 
gree of fineness that they allow air, moisture, and lime, rapidly to convert vegeta- 
ble matter into soluble geine, and yield it up readily to the roots of plants : but I 
Presume that without fresh supplies of manure, they would not continue to pro- 
duce as long as most of the other soils in the state. A considerable part of our al- 
luvia are yearly recruited by a fresh deposite of mud, which almost always con- 
tains a quantity of geine and of the salts of lime, in a fine condition for being ab- 
80rbed by the rootlets of plants. And on other parts of alluvial tracts, our farmers, 
I believe, are in the habit of expecting but a poor crop unless they manure it yearly. 
Yet so finely constituted are these soils, that even if exhausted, they are more easi 
¥estored than most others; so that taking all things into the account, they are 
