382 _pfN-ACCOUNT OF THRTT 
Tuy results found from this table may be ¢orrected ; by, applying the 
numbers from the preceeding, although it. may admit. of doubt. if in sa 
survey of this description, any quantity much below 1 be worth regarding. 
TABLE 9. 
Contains the logarithmic factor for correcting the preceding result, 
‘though the operation of this correction be far too feeble to deserve being: 
attended to. It is less than that oiven in Table 7. The logarithm in the 
iable is-to be added to the logarithm of the correction found by the pré- 
ceding, the sum is the logarithm of the correction. It may be however 
always nee and I have only given the table to shew how Gah 
TABLE 10. eae 
Conrains the factor natural and ean iia for reducing distances on 
the perpendicular in feet, to their corresponding differences of longitude. 
S 
. ae 
: EXAMPLE, : | , 
nee the length of an arc perpendicular to the meridian == 400 ,000. 
feet. Required the difference of longitude of its two extr eae 
Log. of 400, 000 5:602,060 
Factor to, 30 25 i ee 
4567 9 == 3°659° 710 
Is the difference of longitude required, ye it poust Be corrected by, 
TABLE -llL. ca 2x ee 
Thus, approximate longitude,... 4567-9 
Cor rection, LOsiid as 
p e6@ ©. ‘e\ae 
"Erue differ ence, Kecee ces 400172 
