Economical Geology of Massachusetis. 365 
condition of the organic matter which constitutes the nourish- 
ment of plants.’ 
_ The time at his command, however, was inadequate to a rigid 
analysis of these soils, according to the rules laid down for the 
nicest processes of quantitative research. Being forced to con- 
duct many analyses contemporaneously, the use of silver and - 
platinum vessels was of necessity out of the question; nor was 
there room to verify results by repetition; still he believes that a 
Sufficient approximation to the truth was secured, to answer the 
purposes intended. 
The almost total absence of carbonate of lime is a remarkable 
feature in the soils of Massachusetts. But seven specimens of 
the whole number effervesced with hydrochloric acid, when ex- 
amined with the utmost care to observe this phenomenon; nor 
did either of these examples afford carbonate of lime in a higher 
ratio than about 3 per cent. 
It was a leading object in the research to determine the quan- 
tity of finely divided matter in the soil, since the best soils are 
usually characterized by their fineness. Prof. H. thinks the 
main defect of their soils to consist in the coarseness of their tex- 
ture, and this he very properly attributes to the circumstance of 
their originating, for the most part, directly from primary rocks. 
The salts soluble in water, equalled from 1 to 2 parts in a 
thousand of the soil, and in every case it was believed to contain 
Sulphate of lime (gypsum:) Carbonate of magnesia was also 
very frequently an ingredient, though in mere traces. ‘The pres- 
€nce of soda and potassa was not determined. The peroxide of 
iron exists from 1 to 4 per cent., and upwards in few instances. 
tof, H. regards this last asan useful ingredient in soils. The ra- 
tio of the alumina to the other. ingredients varies from 1 to 18 
Per cent. The instances are common in which he found it above 
10 per cent., which is beyond what might have been supposed 
for a region where the argillaceous formations are so uncommon 
as they are in Massachusetts. 
In respect to the earthy ingredients of a soil, it is undoubtedly 
true that a very wide diversity of constitution is compatible with 
fertility, provided the mechanical condition, and the proportions 
of salts and organic matter are propitious. Prof. H. is of opinion 
that ‘the salts especially admit of but little variation without 
Producing sterility, either by their deficiency or excess; and 
