( 96 ) 
In both cafes you fee the remainder is the 
fame. Suppofe, by way of illuftration, after 
a ballot, I find in the bag 10 white balls and 
5 black ones. If I take out the black balls, 
there will remain 10 white balls in the bag. 
But if before I take out any of the balls, I 
put in 5 white ones, and then take out the 
5 black balls with the fame number of white 
ones to ballance them, there will remain in 
the bag 10 white balls as before. Or fup- 
pofe you were five pounds in my debt, and 
that you are worth nothing, you are then 
five pounds worfe than nothing. Your cafh 
account is 5 pounds. But if any friend 
fhould pay the debt, by thus adding his + 
five pounds to your five pounds, he actu- 
ally fubtrafts your debt : fo that, in this cafe, 
addition and fubtradlion are the fame. 
LET. 
