J^34 BOARD OP AGRICULTURE. 



from which it is made. The carbon which we have thus made is 

 charcoal. It constitutes 10 parts in 100 of the buckwheat when 

 air-dried. The vapors which were given ofl', and which have 

 nearly all condensed in the cooler parts of the glass apparatus, are 

 found to consist of coal gas, coal tar and water, composed of 

 carbon, hydrogen and oxygen. The other way is to burn the 

 plant cautiously in a glass or platinum vessel, with a slow current 

 of air supplying the oxygen necessary to complete combustion, 

 and with, an apparatus to save all gases given ofi'. At the conclu- 

 sion of this experiment it will be found that a little fragile skeleton 

 of the plant is left behind, but it is not black like the carbon 

 residue. It is white and very light, and weighs onlj?^ two per cent, 

 of the whole plant burned. This skeleton is called the " ash.^' It 

 is composed of various compounds of lime, soda,, and other 

 substances which we must soon notice more in detail. The vapors 

 which were given off are made up of carbonic acid and water. 

 The carbon in the latter case is burned, in the former experiment 

 it was saved chiefly as charcoal. 



In recapitulation it must be seen that the constituents of the 

 buckwheat are compounds of carbon, hydrogen, oxygen, calcium, 

 sodium, &c., but these elements do not exist in these forms in 

 the plant. The skeleton which was left after burning the plant 

 contained phosphates, silicates, sulphates and chlorides of various 

 elements ; the gases which were given off during the combustion 

 existed in the plant in complex compounds known to chemistry as 

 water, cellulose, starch, &c. Sometimes the ash constituents are 

 spoken of as inorganic, and the volatile portions as organic, 

 because the former exist also in the inorganic world or mineral 

 kingdom, while the latter are found only in organized structures. 

 It is also said that the inorganic constituents are obtained from the 

 soil, while the organic portions are built up from gases which exist 

 in the air or dissolved in water. But the distinction between 

 organic and inorganic constituents is not as plain as it would at 

 first seem, for they are so closely interwoven that it is almost 

 impossible to say where one leaves off and another begins. Still 

 the distinction between an organized structure and an unorganized 

 substance is such as admits of no mistake. This brino's us to a 

 study of the plant from another point of view, namely, one strictly 

 anatomical instead of chemical. If any part of the buckwheat 

 which we have taken for an illustration be carefully sliced into a 

 very thin section, it will be found under a high magnifying power, 



