g@ -ELECTRICITY OF SHAVINGS OP WOOD. 



nomenoni and after fatisfying myfelf that it was not occafionefl 

 by any moifture or roughnefo on the fubftance ; I fufpected 

 that electricity Was the caufe, and I accordingly fet about the 

 experiments which are the fubject of this communication, 

 pry warm beach I laid a circular tin plate, 6 inches in diameter, on the cap 

 is pofitive, °f Bennet's electrometer, and with a piece of dry and warm 

 window gfafs, fcraped a piece of dry and warm beach, a few 

 of the (havings being received on the tin plate, made the gold 

 leaf fir ike the fides of the bottle with pofitive electricity. 

 This was always the cafe whether the wood was hot or cold, 

 but not always equally ftrong. 

 with fteel nega- I thought a knife would be more convenient than glafs to 

 tlvc# fcrape with, and when I tried it, I found the (havings were 



negatively electrified, although they were taken from the fame 

 piece of wood which before gave pofitive. 

 Other woods. This change in the refult induced me to try different wOods 



in different ways (fometimes fcraping and fometimes cutting 

 fiiiall chip's) but obtained very uncertain refults, for fometimes 

 I obtained pofitive and fometimes negative electricity, even 

 when I cut the fame piece of wood with the fame knife. 

 An infulated I next fixed the blade of a penknife into a glafs tube, co- 



knife acquires vere d w i t h fealing wax, and fet to work with this infulated 

 electricity. knife, and found that it was always electrified with the con- 

 trary electricity to that of the chips which were irioft fre- 

 quently pofitive. But as they were fometimes negative, I 

 repeated the experiments very often to difcover the caufe, but 

 with very little fatisfaction. 

 A flurpinfulat- However, after making feveral hundred trials,, I found the 



cd knife gave k eenne f s f t h e e( jcr e of the knife had fome influence, for one 



negative chips j © * 



a blunter pofi- day after chipping with the infulated knife, and getting pofi- 



tlve " tive chips, I fet the knife on a hone to make it cut better 



(which I had frequently done before) and when I began to 

 chip the fame piece of wood which but juft before gave pofi- 

 , tive chips, I found the chips were negatively electrified feve- 



ral times, I then chipped the fame piece of wood with a knife 

 that had been very much ufed, without (harping, and this gave 

 pofitive chips as the other had done before it was fiiarped ; the 

 knife that had been fliarped was tried again, but the chips 

 were pofitive now, however when it was fharped again it 

 gave negative chips. 



I now 



