. JOURNAL 



OF 



NATURAL PHILOSOPHY, CHEMISTRY, 



AND 



THE ARTS. 



JUNE, 1804.. 



ARTICLE I. 



Letter from Mr. Ezekiel Walker, on the Methods of oh-, 

 ferving the Longitude at Sea ; with an Exhibition of the very 

 great Accuracy of the mean Refult from a Number of ChrO' 

 nometers. 



To Mr; NICHOLSON. 

 SIR, 



JL HE two moft approved methods of finding the longitude Longitude found 



at fea, are thofe by lunar obfervations and by time-keepers. ^^ .'""" obfer- 

 ... ,,r .. 1 1 ^1,. vations and by 



Although thole methods are now brought to coniiderable per- time-pieces. 



fe6tion, yet they can only be looked upon as in a progreffive 



fiate towards that point of precifion, at which the aflronomer 



and the artift have long been labouring to arrive. 



The lunar theory is ftill but imperfectly underftood; but per- Both methods 

 haps the time is at no great diftance, when it (hall be as well ftill improveabk. 

 known as the theory of any other planet. Nor is it unphilo- 

 fophical to fuppofe, that fome property of matter, which is at 

 prefent unknown, may hereafter be difcovered, by means of 

 which a time-keeper may be fo conflru6ted as to perform as 

 well at fea as a regulator on (hore. 



Thefe are conjedures, though probable, that I (hall not in- 

 fift upon any further, but proceed to inquire into the merits of 

 the two methods in their prefent ftate of perfection. 



Vol, VIII.—JuNE, 180t. F The 



