800 MASSACHUSETTS AGRICULTURE. 



mould camo from the rocks, and is rich oftentimes in their min- 

 eral cons-titucuts. It only needs to be brought up to the sur- 

 face, so that the air and rain can reach it, to promote chemical 

 decomposition and fit it for important plant aliment. 



I doubt not that oftentimes a farmer has applied gypsum to 

 his land tuCering frcm the want of lime, when he might have 

 obtained all that was necessary by subsoil ploughing and active 

 tillage. 



Chemii-try teaches that plants do not obtain all the elements 

 of tlieir growth from the mingled rock dust and humus consti- 

 tuting the soil. The atmosphere comes in for a share in rear- 

 ing tlie structure, and the aid it renders is voluntary, and en- 

 tirely independent of help from the husbandman. He cannot 

 promote his interests and increase his crops, by endeavors to in- 

 fluence atmospheric action upon his plants. It is only through 

 the soil that lie is able to do this. Plants derive their carbon, 

 or charcoal, chiefly from the air. The great bulk of all plants 

 is charcoal, and consequently we see how important is the aid 

 derived from that soiirce. 



How many of you, gentlemen, call to mind the fact, as you 

 sit around your comfortable hearth-stones in the long evenings 

 of winter, and witness the gradual transmutation of the blazing 

 pile of wood into black lustrous charcoal, and then, by further 

 combustion, apparently into a heap of ashes ? How many re- 

 member that there is in the one a constituent of the very \^inds 

 from which you are so effectually sheltered, and in the other 

 a portion of the soil abstracted from your fields ? I am per- 

 plexed to understand how a farmer can witness these wonder- 

 ful changes every day of his life, and not have sufficient curios- 

 ity awakened to lead him to interrogate that beautiful science, 

 which is competent to answer his every question and satisfy his 

 thirst for information. 



The facts as stated are of themselves paradoxical and diffi- 

 cult of apprehension. There is no charcoal in the earth, none 

 in the air, and yet, if we allow fire to act upon a bit of the 

 whitest Avood, a portion of wheat, or corn, or an apple, or starch, 

 or sugar, it is always produced. Does fire produce it, manufac- 

 ture it ? or docs it simply develop what was positively in their 

 substance before? Chemistry affords an answer to the question. 

 Suppose a good housewife places in her heated oven an apple, 



