PREFACE. 
It is hoped also some able enquirer into Na¬ 
ture, will think it worthy attention to investi¬ 
gate the analogy and connexion between vege¬ 
tables and minerals; and whether there exists 
such a sensible analogy, that by inspecting the 
plants which grow naturally on the surface of 
any place, the quality of the soil may be disco¬ 
vered, as also the several sorts of minerals it 
may contain.* 
R. W. D. 
Elston,! 
Notts • / 
in general turn red with acid (indigo is an exception, being soluble 
in acid ; as is also the root of the mercurialis perennis, which, by 
exposure to the air, will frequently become a brilliant blue), hence 
we observe a red colour developed in vegetables, in which an acid 
continually acts, as in the leaves of sorrel, vine, &c.—Nicholson’s 
translation of M. Chaptal's Elements of Chymistry, in 3 vols. printed 
1791. 
* The lichen calcarius receives its name from its peculiarity in 
growing on lime stone rocks; that wherever that stone occurs 
amongst others, it may be distinguished by this plant growing upon it. 
Dillon's Travels through Spain, printed-1782. 
The digitalis and arenaria are found on sandy soils r and others are 
only found on boggy and marshy soils; as the rubus chamcemorus 
(cloud-berry), and thp vaccinum oxycoccos (cranberry) are found on 
peat bogs. ♦ 
