[ 65 ] 
Example. 
In 6000 Julian years, 24 days, 4 hours, 59 mi- 
nutes, 52 feconds, How many mean luna- 
tions ? 
Years 
6000 
Days j 
^ 20 
* 4 
Hours 
... “ 
4 
Minutes ■ 
> 50 
1 9 
Seconds - 
r 50 
1. ^ 
Lun. Dec. of a L. 
7421 1.18023 176 
0.677263795 
0.135452759 
0.005643865 
0.001 175805 
0.00021 1645 
0.000019596 
0.000000784 
Anfwcr 
74212.000000009 
This (hort method may be ufeful in many other 
cafes ; but, as yet, I have only applied it to two. 
The firft of which is, to find the number of troy 
pounds contained in any given number of avoirdupoife 
pounds, and the reverfe. The fecond is to find the 
quantity and weight of water that would fill an up^ 
right pipe of any given diameter and height : and 
confequently, to know what power would be required 
to work a common pump, or any other hydraulic 
engine, when the diameter of the bore of the pump, 
and the height to which the water is to be raifed, 
are given j proper allowance being made for fridfion. 
Thefe two cafes are as follows. 
VoL. LV. 
K 
