17 De general Uſe file canonIII. Achird way in Arithmetick is by Divifon and Diviſion, for wherebene the ſecond Number is les than che firſt, they may divide the firſt byAlrilor z. che lecond, and then again divide che chird by the Quotient. As.or. here, dividing 12 by 4, the Quotient is 3 then dividing 24 by 3, the

Quotient is 8.. 5According to this way we take the Logarithm of che ſetond out of theLogarithm of the firſt, and tlien take the Difference out of the Logarithm

ol che third: ſo that which remaineth ſhall be the Logarithm of che fourth

Number required.Thusche Logarithm of the firſt Number 12 is 1207918 5The Logarithmof the ſccond 2 0. 6 205 999Ihe Difference decreaſing. 47712126.dubtractetl from the Logarithm of, 24 1, 38021124Gives the Logarithm- of 8 o. 90308999

Theſe two latter ways by Difference of Logarithms, may be conſider-ed as the ſame. Though there be ſome difference between them, yet thatmay eafily be reconciled, if we have regard to the nature of the queſtion.For three numbers being given in direct proportion, if the ſecond be.greater than the firſt, the fourth muſt be greater thian the third: Iche ſecondbe leſs than the firſt, the fourch mult be leſs than the third, and cheir Lega-

Fkruhms accordingly. But in reciprocal proportion, conſidering the fiiſt andlecond numbers to be of one denomination, e are to obſerve the contrary.

If we deſixe to turn Sabtraction into Addition, e may take the Lo-

garithm which is to be ſubtracted out of the Radius, and add the Com- iplement. So the Sum of this Addition, the Radius being ſubtracted, ſhall f

give the required Logarithm as before,Thus in the laſt Example: where ſubtracting the Difference 47712126out of 1. 38021124 the Logarithm of 24, we found che Remalndler to bev.90 308998 che Logarithm of g.

The Radius being 1 I O. oοοThe Logarithms to be ſubtracted i 0. 47712126The Complement to the Radius is 9.52287 874This added to the Logarithm of 24 1.380 21124Oives us. a compound Logarithm 40,0% 9