490 TRANS ACTIONS OF THE 



been objected that analysis of no two plants of tlie same species 

 ever agree. Though this is trne it proves nothing as long as thej 

 originate on different soils. Indeed no two plants growing in the 

 same field are in circumstances exactly identical, and as the 

 plants thus grown are each the resultants of uniform causes with 

 the exception of soil, in the chemical nature of the ground they 

 stand in we are to presume the difference arises. On a former 

 occasion I have shown how hopeless is the prospect of our ever 

 being able to recognise by any quantitative analysis the difference 

 on which these variations depend. 



But the analysis of plants has been carried to as great nicety as 

 possible in the existing condition of chemistry. They differ from 

 a uniformity of chemical composition Avherever they grow but 

 little when compared with other individuals of the same species, 

 and yet quite considerably when compared with other species. 

 Hence the most valuable practical indication of the character of 

 a soil is the known chemical composition of the plants that thrive 

 best in it. This is the indication that has always guided the first 

 settlers in taking up farms in this country from the primitive 

 wilderness, and I know of none other yet worthy of so much 

 reliance. 



To this fact that there are certain limited differences in the 

 chemical composition of the same plant grown on different soilSy 

 we must attribute certain peculiarities in the distribution of 

 plants. Thus the cucumber wood tree is found in this country 

 only in the " Genesee Valley," and to the south of it to its limit 

 of climate extending neither to the east nor west. The Geologi- 

 cal Survey of this State speaks of the old red sand stone formation 

 as appearing through just this district. The tamarisk tree does 

 not inhabit the soil of the Catskill mountain rock though it 

 extends to the north and south. The sassafras also, is never found 

 in this formation though existing abundantly in the North river 

 counties, and extending in New Hampshire as far as 43'^ north 

 latitude, and existing on western formations. The locust, which 

 is a native American tree, in the original distribution was never 

 found within fifty or one hundred miles of the sea. The balsam 

 spruce, existing on the old red sand stone, does not cross to 



