330 Olservations on the present Stale 
observations. Probably most of the authors of these rules are 
aware that they are founded entirely on conjectural principles, 
and that in applying them there is always a chance of increasing 
the error which they are intended to correct. Yet the attention 
of mariners is continually called to their republication under va- 
rious forms; and without being accompanied by a single hint 
that any practicable method of finding the longitude at sea by 
observation has vet been discovered. 
It has undoubtedly some relation to the peculiar views of such 
- persons, that among many ordinary seamen an opinion prevails, 
that though the finding of the longitude by observation at sea is 
a matter of great and obvious utility, vet the methods which have 
been hitherto proposed for its determination are difficult to prac- 
tise, and uncertain in their results. 
On the difficulty of the subject it becomes not a man to give 
an opinion, who has never tried in earnest whether there is any 
thing in it beyond the reach of his own faculties. Indeed, any 
person acquainted with arithmetic, and who has no imperfection 
in his sight, may soon learn to practise the method of finding 
the longitude by lunar observations with perfect success. This 
remark is not made without due consideration ; but it is too evi- 
dent to admit of question, that one of the great causes which 
hare prevented the general introduction of the lunar method of 
finding the longitude into general practice in the merchant service, 
is the little attention that has beeti paid to giving instructions 
in the art of observing by many teachers of navigation. 
The certainty of the results will of course be proportioned to 
the care with which the necessary operations are performed ; but 
in the hands of a careful observer, the greatest probable error is 
too insiguificant to be regarded. That persons of indolent or 
slovenly habits are.unable to derive much advantage from this, 
or any other method of finding the longitude by observation, is 
surely neither an argument against its utility, nor matter of sur- 
prise in itself, 
To estimate fairly the weight of this objection, however, and 
to determine by actual experiment what confidence may now be 
placed in the results of lunar observations, the following series was 
taken to determine the longitude of the Trinity House School, 
Newcastle. The observations were made under a great variety 
of circumstances, and the uniformity of the results is certainly cal - 
culated to give confidence in the method by which they were 
obtained. The altitudes, which were compuled, are omitted, for 
the sake of bringing the figures within the breadth of a page; 
but any person who thinks proper may re-calculate them, ob- 
serving that the latitude of the place where the observations were 
made, is 54° 581’ N. 
Lunar 
—— 
