Outlines of Horticultural Chemistry. 131 



become a universal language, in which the facts that are ob- 

 served in their art, may b^ so clothed, as to be intelligible to 

 all ages and nations." 



If it were true, which it is not, that the cultivation of the 

 soil has not improved during the last two thousand years, 

 though some have argued for such an untenable opinion, yet, 

 supposing it to be true, such an argument ex ignorantia 

 would avail nothing against the possibility of improvement. 

 Does not every cultivator of the soil know that some ground 

 will grow luxuriant crops, such as a second piece of ground, 

 though manured without limit, will never equal? All that he 

 can say is, that " the ground does not like those crops ;" but 

 the chemist can teach what constituents are deficient, what 

 noxious ones are present, which, in less incorrect language, 

 causes the croj^s not to like the soil. I am perfectly willing to 

 grant, and to lament that facts justify the admission, that che- 

 mistry has not been brought to the illustration of the agricul- 

 tural arts so successfully as to many of the arts of manufacture ; 

 this is in a chief degree owing to the insensibility of cultivators 

 in general, but not entirely so. It partly arises from the great 

 difficulty and intricacy of vegetable chemistry ; " if the exact 

 connection of effects with their causes," says Kirwan, " has 

 not been so fully and extensively traced in this as in other 

 subjects, we must attribute it to the peculiar difficulty of the 

 investigation. In other subjects, exposed to the joint opera- 

 tion of many causes, the effect of each, singly and exclusively 

 taken, may be particularly examined, and the experimenter 

 may work in his laboratory, with the object always in his 

 view ; but the secret processes of vegetation take place in the 

 dark, exposed to the various and undeterminable influences of 

 the atmosphere, and require, at least, half a year for their 

 completion." But such difficulties are only so many power- 

 ful reasons for increasino- the labourers in this field of science ; 

 and when these have gone on collecting observations and facts, 

 some master mind will arise, in an age perhaps not very dis- 

 tant, and render the whole more luminous, by arranging them 

 in the magic order of system. 



The second prejudice to which I shall advert, is that which 

 considers chemical experiments cannot be tried without ex- 

 pensive apperatus, a prejudice to the full as futile and base- 

 less as the preceding. To demonstrate this, but one fact need 

 be stated. The late Dr. Henry of Manchester, whose expe- 

 riments were so nimierous and so varied, so intricate yet so 

 accurate, " was at no period of his life in possession of a well- 

 furnished laboratory, or of nice and delicate instruments of 

 analysis or research ;" but his ingenuity " was especially dis- 



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