Geological Surveys of Kentucky and Arkansas. - 25) : 
was fertile with new truth, but it must henceforth be a tool for 
occasional use, and not an engine of discovery. With our ad- 
vance in knowledge there must be an advance in methods of 
finding out the unknown. Soil-analysis was indeed a means of 
insight into the secrets of vegetable growth, but it carried with 
it the measure of its limit. What we call telescopes do not ena- 
ble us to see the end i 
To study the soil in the hope of benefitting agriculture, we 
must regard all its relations to the plant. e must examine it 
not merely from those points of view which theoretical chemistry 
suggests, but especially from those which a knowledge of prac- 
tical agriculture furnishes. This is becoming more and more 
the habit of agricultural chemists and the results are of the 
happiest kind. : 
t us remember what the illustrious Nestor of Agricultural 
Science, Boussingault, has said as the summing up of his pro- 
‘tacted experience and study. , : 
“At an epoch not far distant it was believed that a strict 
arable soil. Numerous analyses shortly modified this opinion as 
00 positive. The sagacious Schiibler even sought to prove in a 
Tesearch that has become classic, that the fertility of a soil de- 
