184 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Prof. Nash. — I think not ; but I am not positive about that. 

 I had in view simply stubble ground, and ground devoted to hoed 

 crops the year before. In cutting a piece of wood with a chisel 

 across the grain, it will take four times as much power to take oflf 

 a shaving two-fiftieths of an inch thick as to take off a shaving 

 one-fiftieth of an inch thick. The power required increases not 

 directly with the thickness, but as the square of the thickness. 

 If I were to undertake to cut off an inch at a time I could not do 

 it. So you will see carpenters taking off many shavings, because 

 they can cut many small ones more easily than one large one. 

 So it is in the soil. These vertical cutters are so arranged that 

 the first cuts its shaving, and is followed by the second, so far 

 behind as not to allow the earth to become wedged between 

 them. Placing four more vertical cutters (making nine in all, 

 counting the standard) a little behind the others, we have a per- 

 fect potato digger. 



Mr. Carpenter. — This may answer the purpose in part ; but, as 

 a whole, it seems to press down the earth below, while lightening 

 it above. The mole, on the contrary, mellows the ground both 

 above and below. There should be something here to manipu- 

 late the soil below the horizontal cutter. 



Prof. Nash. — That can be done with a sub-soil plow. 



Mr. Carpenter. — That is a double operation ; besides, there is 

 the same difficulty at the bottom of that. The spading fork is 

 nearest to perfection of anything we have now. 



Mr. Robinson. — I think if I were to undertake inventing, I 

 should take a hint from the buzz-saw, and invent something to 

 saw up the earth and convert it into sawdust. 



ISABELLA GRAPES. 



A gentleman exhibited Isabella grapes from Washington, in 

 Dutchess county, N. Y. The ground is upon a limestone base, 

 which does not hold the water freely. The vines are always 

 buried in winter. 



Mr. Carpenter. — I will repeat that I do not believe the Isabella 

 grape can be grown successfully in ordinary culture north of this 

 latitude. By burying the vines they are advanced and ripen 

 with greater certainty. I refer to open culture. We have the 

 Concord, which is sure without special care in burying the vines, 

 and it is conceded to be about equal to the Isabella. Why, then, 

 should we encourage the culture of a grape, which is so uncertain 

 as the Isabella, north of this latitude ? 



