( 1 14 
tiplication and Divifion of whole numbers, 
fractions vulgar and decimal, and of Alge- 
braic quantities. I fay a rational idea, dif- 
tinguifhed from the mechanical fyftem of 
introduction, which you will find in the ele- 
mentary books. What I have done is no- 
thing more than a partial explanation, or 
analyfis, of the machines with which you 
are to work: a tolerable comprehenfion of 
their conftruflion, cannot fail to facilitate 
your future labours. 
Fek. 
LET- 
