244 BOARD OF AGRICULTURE. 



have in our crucible two pounds in weight out of every hun- 

 dred of which the oak was originally constituted. Ninety- 

 eight parts out of every hundred have taken on an invisible 

 form, and disappeared. We have found nothing that resem- 

 bles sod. 



Go a single step farther, and ask the chemist to take 

 what we call the " ash," and apply his tests, and tell us what 

 material it is, and whence it is. Applying his chemical tests 

 to the ash, the chemist tells us, " Here is silica, here is potash, 

 here is lime, soda, magnesia, phosphoric acid, sulphuric acid, 

 chlorine, iron." We have not reached our point yet. Neither 

 you nor I ever knew lime as lime in the soil ; we never knew 

 potash as potash in the soil. Although we are familiar with 

 all these elements in the arts, yet we have never found them 

 in the soil ; and the question comes back. Whence this mate- 

 rial that the plant has found wliich we call " ash " ? And 

 therefore we go to the soil, and see if we can find it there. 

 A casual examination of the soil discloses this first. Here is 

 a mass of fibrous and cellular material that seems to be in a 

 decomposing or broken-down condition. That, we conclude 

 at once, must be the decaying materials which have come 

 from the former growth of plants. Further than that, we 

 find under the microscope that this soil is made up of small, 

 broken, sometimes rounded, sometimes angular pieces of rock, 

 similar to the rocks which are in our fields and in the coun- 

 try around us, — pieces of quartz, pieces of granite, of mica- 

 ceous and talcose rocks, and of limestone rocks ; but still we 

 do not find any thing like what we find in our crucible, and 

 call it ash. 



Further careful examination discloses the fact that these 

 particles of rock of which our soil is composed are dis- 

 tinct minerals. Here we find talc, we find mica, we find 

 hornblende, we find felspar, we find calcite, magnesite, apa- 

 tite, and phosphorite ; but we have found neither lime, nor 

 potash, nor soda, nor magnesia, nor any thing which we find 

 in the ash: we find simply distinct, well-knoAVQ minerals. 

 Call on the chemist again. What says he ? All these min- 

 erals are distinct, well-known chemical compounds. They 

 are not only particles of minerals which constitute rocks, but 

 they are, away back and behind all that, distinct, well-known 

 chemical compounds. They are a union of silica, more gen- 



