of Nautical Astronomy. 333 
If we suppose that only ten such observations could be obtained 
on a voyage from America to Europe, the distance would then be 
divided into parts of two or three hundred miles in length, at the 
end of each of which the place of the ship would be known with 
probably greater exactness than the geographical situation of 
Tinmouth was till towards the close of the last century. And 
if the mariner were provided with a chronometer to connect his 
junar observations with each other, he would at all times have 
such a knowledge of his situation, as would enable him to take 
the best measures for bringing his voyage to a successful issue. 
Enough has, perhaps, been said in reply to those who surmise 
that the lunar method of finding the longitude is uncertain in 
its results. It is hoped also, that enough has been said to con- 
vince those connected with the shipping interests engaged in the 
general foreign trade of the country, of the great importance of 
the modern improvements in nautical science; and of the expe- 
diency of requiring in those intrusted with the charge of their 
property at sea, a more intimate acquaintance with those im- 
provements than at present they generally possess. 
That a ship on being sent to sea is furnished with a sufficient 
stock of unexceptionable materials, the merchant and the insurer 
are generally very careful to ascertain ; but it is in comparatively 
few cases indeed, that any inquiry is made respecting the qua- 
lifications of the person who is to command her, though, in esti- 
mating the risk of the voyage, those qualifications are of para- 
mount importance. 
That the master of a ship should be sOber i in his habits, eol- 
lected and ready in circumstances of difficulty, perfectly acquaint- 
ed with the management of a ship, and with the local dangers 
of the coasts which he may have occasion to visit, is too obvious 
to require remark. The importance of these primary qualifica- 
tions for the office of a master mariner is universally admitted. 
Besides these qualifications, however, a master employed in the 
foreign service should be acquainted with every branch, either 
of art or of science, that may either enable to determine his si- 
tuation at sea; or contribute in any way to the speedy and suc. 
cessful termination of his voyage. 
But many, very many masters of merchantmen are perfectly 
unacquainted with many important branches of the art which it 
is their business to practise. Of those among them who have 
so far acquainted themselves with the great modern improvements 
in navigation as to be able to reduce them to practice, the 
number is surprisingly limited; and a great majority of them 
follow, without improvement or alteration, the practice of their 
predecessors who a hundred years ago were engaged in the same 
employment, Nautical Tables, Charts, and Instruments for ob- 
servation 
