248 
CULTURAL CHEMISTRY. 
(^Continued from page 229.) 
The substances to which the term Inoeganic Elements has been of late inju- 
diciously applied, now claim attention. They consist of those earthy, mineral 
matters, which abound in the soil, and are occasionally present in plants, though not 
referable to the atmosphere, its constituent gases, or to other gaseous fluids adven- 
titiously combined with it. At the period when Sir Humphrey Davy paved the way 
to the introduction of chemical science, by his Lectures before the Board of Agri- 
culture, from the year 1802 to 1812, the analysis of earths and soils by chemical 
re-agents became the order of the day ; and, adopting the processes described by that 
philosopher in his Lecture IV., commencing at page 141, Edit. 4th of his 
“ Elements,” numbers of experiments were performed, which led to* the conclusion, 
that the main constituents of a highly fertile natural loam were silicious sand, fine 
silica, alumina or the base of clay, carbonate of lime or chalk, and oxide of iron ; 
being five purely mineral matters, which were viewed as the essential bases of all 
earths capable of supporting vegetable growth. 
Practical men, however, became dissatisfied with the results of such experiments, 
which, they began to think, led to no real utility. Enquiry, therefore, was for a 
time arrested, or made small advances in England, although it must be confessed, 
that on the Continent men of enlarged mind and great analytic skill, persisted in a 
series of researches which have led to important discoveries. Professor Johnston, 
to whom we have so frequently appealed, thus expresses himself, in a note on 
Analysis, which appears at page 224 of the “ Royal Agricultural Journal,” 
No. XXI. 
“ In this branch of applied science, I know of few things more difficult than to 
give a safe and practically useful interpretation to the numerical results obtained 
from the analysis of a soil ; and I can well understand the sources of the opinion 
that the analysis of a soil is of no use. It requires much knowledge of practical 
agriculture to see their value, or to understand what the numbers indicate.” This 
remark holds equally with horticulture ; and in another place Mr. Johnston refers to 
the results likely to be obtained in a large trial garden, conducted by competent 
persons. In fact, the thousands of subjects which the general horticulturist has to 
deal with, urge the importance of scientific investigation, with peculiar force. 
“ When a really well-instructed chemist,” adds Mr. Johnston, “ ventures to 
pronounce the minute and rigorous analyses of soils of no use, I feel only regret that 
the weight of his opinion should be thrown in the way of a means of improvement, 
which, if he knew' more of practice, he would see was not only largely available, but 
in many cases almost indispensable to a safe expenditure of money upon the land.” 
The real difficulty, which presents itself as an almost insurmountable obstacle to 
