PROCEEDINGS OF THE HORTICULTURAL ASSOCIATION. 707 



adapted. These plants are found to consist of an organic portion which 

 burns or is driven off by heat, and an inorganic portion left in the residue 

 or ash. In its growth the plant obtains the materials which add to its bulk 

 from water, from the air and from the soil. The earth}' elements of tho 

 plant come directly from the soil, while the others, oxygen, hydrogen, car- 

 bon, nitrogen, etc., are derived from the air and from water. Do Saussure, 

 in the early part of the present century, first made known the fact that 

 plants would not grow unless they found in the soil the ingredients of their 

 ash. This has repeatedly been confirmed, and it now seems strange that 

 "what is at present so well established as the very ground-work of agricul- 

 tural reasoning should have caused so much investigation. A soil was 

 imitated with comminuted platinum, washed with acids, and heated to red- 

 ness, consequently containing nothing which a plant could appropriate. 

 The seeds planted in this soil germinated, and grew for a while, but when 

 the ash ingredients contained in the seeds were used up, they died. The 

 substances found in the ash of plants, are potash, soda, lime, magnesia, ox- 

 ides of iron and manganese, chlorine and carbonic, sulphuric and phosphoric 

 acids. These are absolutely essential to the perfection of plants. Another 

 experimenter, Prince Salm Hortsmar, found that the oat would not thrive and 

 perfect seed if a single ingredient of the ash was withdrawn from the soil. 

 The plant receives these ingredients in the water absorbed by its roots; 

 hence, nothing in the soil is available as plant-food, which is not readily 

 soluble in water. 



When these facts became known everybody saw at once the great bene- 

 fit chemistry was about to be to agriculture. The plants must be analyzed 

 and their demands upon the soil known; then the soils must be analyzed 

 and what they lacked made apparent, and last!}'", the manures must be 

 analyzed, or at least those obtained which would make any soil exactly 

 what the crop to be raised demanded. Agricultural chemistry was one of 

 the most beautiful branches of science. The world was entering upon a 

 new era in the art of cultivating the soil, and the rate at which it was 

 making progress must have been rather alarming to the old fogies. But 

 alas the science was in its infancy and it had been too heavily laden by 

 these Utopians — it failed to do this work. It soon became appareiit that 

 no soil analj'sis when made in the best possible manner could show the 

 fertility of a soil. Practically soil analyses do not exhibit the available 

 constituents of a soil with any very great degree of accuracy. Charlatans 

 who talk learnedly advise those who consult them to have their soils 

 analyzed, and on the strength of these analyses make prescriptions for the 

 soils — often too with excellent results. For where is the soil that bones, 

 gypsum, ashes, etc., will not benefit? 



Water is not only indispensable as a solvent of the plant-food, but it is 

 food itself. The absorption of water takes place through the roots alone, 

 hence all the water plants- receive comes through the soil and much of it 

 is breathed out through the leaves. The immense quantity of water thus 

 transferred from the soil to the air is hardly conceivable. It often amounts 

 to more than the entire rainfall. Mr. Lawes, of England, estimated that 

 for every grain of solid matter added to the plant in its growth, it trans- 

 pired 15G to 270 grains of water. A crop of grass therefore which weighs 



