table alkali ; when it grows on the sea-shore, where 
compounds which afford the fossile or marine alkali 
are more abundant, it yields that substance. Du 
Hamel found, that plants which usually grow on 
the sea-shore, made small progress when planted 
in soils containing little common salt. The sun- 
flower, when growing in lands containing no nitre, 
does not afford that substance ; though when 
watered by a solution of nitre, it yields nitre abun- 
dantly. The tables of De Saussure, referred to in 
the Third Lecture, show that the ashes of plants 
are similar in constitution to the soils in which 
they have vegetated. 
De Saussure made plants grow in solutions of 
different salts, and he ascertained, that in all cases 
certain portions of the salts were absorbed by the 
plant, and found unaltered in their organs. 
Even animals do not appear to possess the power 
of forming the alkaline and earthy substances. 
Dr. Fordyce found, that when canary birds, at the 
time they were laying eggs, were deprived of access 
to carbonate of lime, their eggs had soft shells; 
and if there is any process for which nature may 
be conceived most likely to supply resources of 
this kind, it is that connected with the reproduc- 
tion of the species. 
As the evidence on the subject now stands, it 
seems fair to conclude, that the different earths 
and saline substances found in the organs of plants, 
are supplied by the soils in which they grow ; and 
in no cases composeed by new arrangements of 
the elements in air or water. What may be our 
ultimate view of the laws of chemistry, or how far 
