30 RYE. 



sun glass. The focus, which is formed by the refrac- 

 tion of the rays in passing through* the double convex 

 lens, sets on fire the segar or any other object present- 

 ed ; but if a piece of muslin or any other substance 

 is interposed between the lens and the segar, no effect 

 is produced. It is precise!} the case with land. If 

 the sun shines down on its naked bosom, the gasses 

 which arise from it, carry off into the atmosphere the 

 richest particles of its substance. But on the contra- 

 ry, if the soil be covered with a thick coat of grass 

 or clover, the sun's rays are excluded, and instead of 

 losing, the earth is continually abstracting nitre from 

 the rains, hails, dews, snows, &c. Strip those rich 

 Prairies of the West, expose the surface to the direct 

 action of the sun, and my word for it, they will every 

 year become poorer, though no crop of any grain may 

 be reaped from them. I repeat it again, and I will re- 

 peat it a thousand times, that the soil is not impover- 

 ished by what is taken off of it, only that when culti- 

 vated it is necessarily more or less exposed to the sun. 

 If land could be cultivated, and at the same time 

 covered with clover from the sun's rays, I should have 

 no hesitation in saying, that so far from becoming 

 poor, it would become rich. 



There is a piece of woodland in Delaware once 

 turned out as a common, and now grown up in oaks, 

 which has become rich. I recollect having noticed 

 the wheat ridges, where fifty or sixty years agograin 

 was cultivated. It became exhausted and was turned 



