( 72^ ) 
ten minutes ^ To that if they mifs an obfervation for' 
two or three days, and do not allow for this Variation, 
they fail not to fall to the Northward of their expefta-^ 
tion5erpecially if they reckon &27/j in above 50 degrees. 
This has been by fome attributed to the Indraught of 
St Georges Channel, the Tyde of Flood being fuppofed 
to fet more to the Northward , than is compenfated 
by the Ebb fetting out.But the Variation being allowed, 
it hath been found that the faid Indraught isnot fenfible, 
and that Ships fteering two Watches E ^ iSfor one Eafl^ 
doexaftly keep their Parallek^ This praftice is- there- 
fore recommended to all Mafters of Ships, who are 
unacquainted with the allowances to be made for the 
Variation as alfo that they come in,out of the. Sea, on 
a Parallel not more Northerly than 49° . 40** whiciv 
will bring them fair by the Lizards 
Printed by Sam. Smith and Benj. Walford^ Printers to 
the Royal Society, at the Primes Arm in St Pauls 
Church-yard. 1700. 
