42 INTRODUCTION. 



The labours of the scientific navigator for the 

 promotion of physics in general, come under two 

 principal divisions : " Astronomical Observations," 

 and " Physical Experiments and Remarks." Not 

 only are such expeditions distinguished from ordi- 

 nary voyages by a more complete and more care- 

 ful astronomical determination of the daily latitude 

 and longitude of the ship, according to the best 

 methods; but it is in such voyages alone that 

 those observations are possible, which may be of 

 advantage to the sciences. Among the first are 

 comprehended, not only those observations by 

 which the daily place of the ship, or the position 

 of the coasts is determined, but such, also, as, 

 though they properly belong to physics, yet have 

 a particular appUcation in astronomy : the latter, 

 on the contrary, relate more to the natural history 

 of our globe itself, and to the phenomena to be 

 observed upon its surface. 



ASTRONOMICAL OBSERVATIONS. 



I. DETERMINATION OF THE LATITUDE AND LONGITUDE. 



Sufficient instructions are given in the general 

 elementary treatises on navigation, respecting the 

 determination of these essential parts of naviga- 

 tion by the ship's reckoning. We merely observe, 

 that such voyages would be precisely the best cal- 

 culated to make a trial of new proposals, to supply 

 the place of the common logs. The simplicity of 



