C 78 j 
ing north eafl:, and afterwards diminifli it again to 
about when the light C will bear due eaft. 
Having now got far enough within the Spurn, vve 
may run due north about a mile and half, firfi; bring- 
ing the two lights to bear in one line due fouth ealf, 
and then opening them again, on the oppofite fide, 
to an angle of about i'’ 30' or 2”, according to our 
diftance within the Spurn*; but here, knowing per- 
fectly well where we are, we can come to an anchor 
in a fafe road, at fuch a diftance from the Trinity 
fand as we pleafe, which diftance may be regulated 
without difficulty by the foundings, as at the place I, 
where the anchorage is very good in five fathom 
water, 
* In the cafe of a fliip’s being placed nearly In the line of the 
two lights, the method of finding onr diftance from them by 
their bearing, and the angle they fubtcnc), will fail us ; but, as 
it may fometimes be convenient to have the means of forming a 
tolerable guefs about our exadf fituation in this cafe, as well as 
others, I muft obferve that a pretty good judgment may be made 
concerning it, by running a little way in a direction nearly at 
right angles to the line of the lights ; for by this means, the di- 
ftance run being known, it will appear, from the change of the 
angle, under which they are feen, how far they are from us. 
Thus, for example, if from the place I, a vdfel fhould run 
about a quarter of a mile along the dotted line 1 K, and find, 
that this made a change in the angle fubtended by the two lights 
of a very little more than a degree, fhe would know herfelf to 
be ajmoft two miles from the light C, as would appear by mca- 
furing the diftance 1 C upon the fcale. 
XI. An 
