48 FiDihcr Remarks on (he ncxv MtiJind ofdclcrinining the 



The table given by Mr. Bowditch consists merely of p. cos t 

 converted into numbers for every lO"", from O*" to 12'', and on 

 the assumption that p is equal to 1° 42'. No correction is 

 given for those povvei's of p which are omitted : and, as the 

 polar distance of the star is assumed 4' greater than it is at the 

 present ilay, it is evident that his table can give but a very 

 rough approximation to the latitude. The American captain, 

 JVom whom M. Zach obtained the above particulars, seemed 

 aware of this circumstance, but did not consider it of much 

 importance, because the altitude of the star was seldom deter- 

 minable within those limits : an error in reasoning too fre- 

 quently adopted. lie said, however, that if greater accuracy 

 were required they (the Americans) had other tables more ex- 

 act ; and mentioned those of Capt. Elibrd, of Charleston in 

 South Carolina, published under the title of " Circular Polar 

 Tables," and a work of Mr. Stevens : neither of which he had 

 in his possession. 



Capt. Elford's work I have not yet been able to procure, 

 neither do I know the date of it; but the jiamplilet of 

 Mr. Stevens has been kindly presented tome by Mr. Trough- 

 ton ; and I avail myself of this opjiortimity of giving a sum- 

 mary of its contents. It was published in this country twenty- 

 two years ago, under the title of " A method of ascertaining 

 the latitude in the northern hemisphere by a single altitude 

 of the pole-star, at any time ; with tables computed for that 

 pxnpose. By John Stevens, in the service of the East India 

 Company. Cambridge 1800." It contains only 16 pages; 

 fbin- of which are occupied by the tables. Table I. appears 

 to contain the value of p. cos t: and Table II. the correction 

 depending on the latitude of the place of observation. The 

 north polar distance of the star is assumed equal to 1° 45'; 

 but a rule is given for correcting the errors which may arise 

 from any variation in that quantity. 



It would thus appear (from the information which we at 

 -present possess") that this method of deducing the latitude 

 of a place originated in this country. But, how it has hap- 

 pened that it should have been so much neglected here, as not 

 to have formed a part of any subsequent treatise on naviga- 

 tion, whilst it has been so speedily adopted by the Americans, 

 I am at a loss to conceive. The attention, however, which 

 has been recently directed to this subject, will probably restore 

 it to its proper situation in all future works which may be 

 written for the information of nautical persons. The corrccS 

 solution of the problem still belongs to M. Littrow. 



M. Zach, who seems to take a pleasure in noticing the zeal 

 and rising talents of I lie Americans, particularly in all nautical 



alKiirs, 



