THE FARMER'S MAGAZINE. 



415 



Mr. Hunt, in reply, urged the importance of 

 keeping meadow land in good heart, and not making 

 merely a convenience of it. He thought it import- 

 ant iin understanding should be come to between 

 landlord and tenant. As to laying down meadow 

 land, he believed it might be seven or ten years be- 

 fore meadow land could be made to pay for the 

 outlay. The first year was fallow, the second year 

 was the sowing, and the third year they would not 

 get much grass ; but at the end of the fourth or 

 fifth years, meadow began to grow in value. He 

 believed there were as great restrictions against lay- 

 ing down arable land into meadow as there were to 

 breaking up meadows for corn, &c. With respect 

 to what Mr. Wilson had asked about the lasting 

 properties of bones, he believed their good eflect 



was visible for ten years. He believed it was the 

 custom in Yorkshire to allow half-dressings for 

 bones two years after they had been put on. He 

 had found wherever he had used bones on meadows 

 it had always produced white clover, although none 

 had been visible before. In conclusion, he thanked 

 the members for the kind manner in which they 

 had received his remarks and hstencd to his paper, 

 and felt very i)leased that it had given such general 

 satisfaction, and that his opinion was so much in 

 accordance with theirs. 



Mr. Wilson moved, and Dr. Powell seconded, 

 a vote of thanks to Mr. Hunt ; and a similar com- 

 pliment having been conveyed to the chairman, the 

 meeting broke up. 



THE FOOD OF PLANTS, AND HOW THEY TAKE IT. 



BY DR. JOHN A. WARDER. 



A paper read before the Pomological and Horticultural Society of Southern Illinois, Dec. 1859. 



Oui investigations among animals disclose to us 

 that some of them consume other animals for food, 

 while others feed exclusively upon vegetable 

 growth, and some, like man, are omnicorous. But 

 a question of food remains to be investigated and 

 answered ; it is this : What is the food of plants ? 

 This I shall attempt to answer, though well aware 

 that it is a question of no mean importance — 

 indeed, it is the very foundation of all thorough 

 imdcrstanding of scientific agriculture and horti- 

 culture. It involves an understanding of vegetable 

 physiology — a science which has received much 

 attention within the past century, but which, owing 

 to human imperfections, has enunciated many false 

 propositions; it has been obliged to consider, and 

 to reconsider these, again and again ; each time 

 claiming to be right, and was so believed until 

 proved to be otherwise. Even now, while v/e ad- 

 vocate our favourite views, the honest philosopher 

 must admit that he is but in his A, B, C of the 

 science. The doctrines upon this subject that 

 have been enunciated by Liebig are remarkable for 

 their perspicuity, and are the most satisfactory, 

 though he too has his opponents, who are not 

 willing to admit the truth of the dicta of the great 

 German agricultural chemist. 



Examining (as a j)reparatory step, before making 

 answer), what plants are made of, we may find 

 some guide in our investigation. Besides small 

 quantities of certain inorganic substances, we dis- 

 cover certain compound bodies, which in chemical 

 language are called proximate principles, such as 

 cellulose, and vegetable jelly, sugar, gum, and 

 starch, all of which are composed of similar ele- 

 ments, combined together in very nearly the same 

 l)roportions ; we also find various oily or fatty and 

 waxy substances differing from the first in having 

 less oxygen in their composition. Besides these 

 we also find nitrogenous matters, that have a very 

 important part to play in the chemical changes 

 that the food of plants must undergo in its proceses 



for the formation of the proximate principles just 

 named. The two important elements in the /ood 

 of plants, therefore, are carbon and nitrogen ; the 

 other elements are found in water, which is com- 

 posed oi oxygen and hydrogen. These four elements, 

 therefore, are of the greatest importance to plants, 

 but of them the former, carbon and nitrogen, must 

 claim our first and chief attention in this inquiry. 

 It has been generally supposed that these substances 

 were provided for plants chiefly by manures, and by 

 the humus, or decaying vegetable matter of the soil. 



The last result of the decomposition of animal 

 and vegetable matters, after the escape of the gaseous 

 compounds, is a dark substance called humus. It 

 abounds in the prairie soil, in most rich soils, in 

 manured soils ; — further, humus is rich in carbonic 

 acid, and ammonia ; hence, when we speak of a 

 soil being rich in humus, we mean that it is well 

 furnished with these elements of plant food— in 

 other words, a rich soil. 



That ammonia and carbonic acid are the sources 

 of nitrogen and carbon, for the supply of plants, 

 there can be no doubt ; and that these substances 

 are produced in immense quantities on the globe, 

 and diffused through the atmosphere, we are equally 

 assured ; but we find the results of respiration, and 

 of combustion, the escape of carbonic acid and 

 ammonia from the craters of the volcanoes, and all 

 our fires, and smoke stacks, do not increase the 

 quantity in the atmosphere appreciably, for there is 

 but a small, uncertain quantity of ammonia, and a 

 definite, small proportion of carbonic acid. These 

 substances are drained out of the atmosphere, and 

 have not increased in it. Geologists tell us that 

 the immense quantities of the coal on the earth, 

 must have been derived from a rank vegetation 

 existing at a former period, when it is probable 

 that our atmosphere was very highly charged with 

 carbonic acid gas. 



How do the grasses and weeds of these great 

 I)rairies, and the trees of our wide and noble forests 



