‘ 
366 Report on a re-ecamination of the 
hence to determine their amount is an important point in agricul- 
tural chemistry. And the differences which are so obvious in 
soils derived from different rocks, do not depend entirely upon 
the different proportions of the earths which they contain. ‘For. 
the quantity and nature of the salts resulting from the decompo- 
sition of rocks are considerably different. 'Thus we should ex- 
pect, that the gneiss and granite soils would contain a larger 
amount than usual of the salts of potassa, and where sulphuret 
of iron prevails, of the salts of iron; the porphyry soils, of the 
salts of soda; the graywacke and sandstone soils, of the salts of 
lime, magnesia, and perhaps potassa and soda; the mica slate 
soils, of the salts of magnesia and potassa; the talcose slate soil, 
of the salts of magnesia: or perhaps more commonly we should 
find the lime and magnesia uncombined with an acid,’ (we do 
not perceive how this can be.) 
‘Such differences as these in the constituents of soil, will un- 
questionably affect their fertility; and it would be desirable to 
ascertain how far they exist in the soils of Massachusetts. Ihad 
hoped to accomplish this object ; but it will require a great num- 
ber of delicate and accurate analyses, demanding far more time 
than has yet been allowed me. As will be seen in the sequel, I 
have attempted to determine the amount of the salts of lime in 
all the soils that I have collected; but it will need comparative 
trials by the ordinary modes of analysis before the peculiar char- 
acteristics of the different classes of our soil can be pointed out ; 
and besides I have made no attempt to determine the existence 
and amount of potassa and soda in my specimens.’ p. 27. 
Prof. H. next proceeds to the developement of a new method of 
analysis derived from Dr. Samven L. Dana of Lowell, Mass., and 
which Prof. H. regards as a most important contribution to agri- 
cultural chemistry. The account is prefaced by the following 
remarks from Dr. D. 
* Geine forms the basis of all the nourishing part of all vegetable manures. The 
relations of soils to heat and moisture depend chiefly on geine. It is in fact, under 
its three states of ‘ vegetable extract, geine, and carbonaceous mould,’ the principle 
which gives fertility to soils long afier the action of common manures has ceased. 
In these three states it is essentially the same. ‘The experiments of Saussure have 
long ago proved that air and moisture convert insoluble into soluble geine. of all 
the problems to be solved by agricultural chemistry, none is of so great practical 
importance as the determination of the quantity of soluble and insoluble geine 1 
soils. This is a question of much higher importance than the nature and propor 
tions of the earthy constituents and soluble salts of soils. It lies at the foundation 
