ITEVT ROTATION OF GROM. 27^ 



But to distinguish the kind of electricity developed in the Mode of dis- 

 -i-iii !• 'i tin^uislnng 

 Stone, the electronaeter must be insulated, by placing it on whether it be 



a cake of resin, and positive or negative electricity may be posiuve or &«* 

 commuuicated to it in the following manner. Place a lin- ^ 

 ger on the metallic base c of the electrometer ; and bring 

 within a proper distance of it a rod of glass, or resin, e^ 

 electrified by friction. When the instrument may be pre- 

 sumed to be charged with the kind of electricity desired, 

 withdraw first the finger from the base, and then the rod of 

 glass or resin. The stone being then presented to one of 

 the knobs of the electrometer, a or h; if the stone repel it, 

 the electricity it possesses is of the same kind as that im--^ 

 parted to the electrometer; if it attract it, it is of the oppo- ^ 

 site kind. 



Some stones communicate positive electricity to the .resin Soma stone*- 

 on which they are rubbed. To discover this, property, a ^o^tTve^g^ec- 

 piece of sealing wax may be flattened on a smooth substance, tricity to resia 

 and the stone rubbed gently on this plane surface. The ^^^ "ictjQa* 

 )cind of electricity the resinous matter has received may then 

 be found by means of the insulated electrometer. 



VII. 



A Method of Sowing Clover, and a new Plan for a Rotation of 

 Crops; by Mr. de V is cess, of Thcde, near Clermont*, 



T the end of winter, after the hard frosts are over, and Clover sowe4 

 when the weather is dry, I sow twenty pounds of clover seed ^^ ^^^ 

 on a septerce of land, about l^OO toises [2500 yards] in cir- 

 cumference, sowed with rye the preceding autumn. This 

 seed is harrowed in with a common wooden harrow, which is ^nd harrowei 

 drawn all over the field by a pair of oxen. Instead of in- ini« 

 juring the rye, this harrowing accelerates its growth, and it 

 actually affords a finer crop than rye that has not been har» 

 rowed. 



When the rye is ripe, I cut it in the usual mode ; and 



• Sonnini's Biblioth. Physico-6cQnomique, Oct. 1807, p 14. 

 ^ when 



