Latitude of a Place, by Ohservaiions of the Folc-Siar. 47 



tlon of the new quantity x, which is here proposed to correct 

 the value of z as deduced from a series of observations. But 

 since the vahie of x depends on three other formuise, none of 

 ■which are of very easy arithmetical solution, it may be doubted 

 whether any thing is gained by the substitution. It is singular 

 that the formulae m and n both contain the value of \|/ : so that 

 in these aiiproximations also the latitude is supposed to be jire- 

 viously known before the general formula can be depended upon. 

 The value of m (if formed into a table, as proposed by M. Lit^ 

 trow) will necessarily require a table of double entry, even 

 for a fixed observatory. The value of A may be taken from 

 M. Delambre's tables of Bediiction to the meridian. M. Lit^ 

 trow adds, as a condition, that the observations must not be 

 very numerous, and that if they are formed into series of four 

 or six, we may safely reject the correction x : but, by this limi- 

 tation and these subdivisions, we lose the benefit of his pro- 

 posed corrections, and thus revert to the orighial general for- 

 mula. His method indeed appears to be somewhat similar 

 to the mode proposed by M. Soldner for determining the time 

 from the mean of a number of zenith distances of the sun or 

 a star: (see Bode's Astronomische Jahrhuch for 1818, page 123) 

 but which M. Delambre (in his investigation and examina- 

 tion of this method, in the Connaissaiice des Terns for 1820, 

 pages 357 and 397) seems to consider not more convenient in 

 practice than the rigorous formula; except in those cases 

 where the observations are made near the prime vertical. 



I shall now proceed to make a few remarks on the histoiy of 

 the iliscovery of this problem : a measure which aj^pears to be 

 called for at the present moment, in consequence of some ob- 

 servations which have been recently made on the subject by 

 M. Zach, in his Correspo7idance Astronomiquc, Till those re- 

 marks ai)})eared M. Littrow was (I believe) generally consi- 

 dered as the original inventor of the method : and in the first 

 paper which he jniblished on the subject in 1817, he himself 

 calls it a ncv: method. M. Zach, however, in a late •iniiiber of 

 his Cor. Jst. (vol. vi. page 210) states that the American sea-. 

 men have been a lon<^ time in the habit of oljserviiig the alti- 

 tude of the pole-star, at all hours of the night, for the purpose 

 of deducing their latitude : and he (luotcs a tal)lc given lor this 

 very pinpose, by Mr. Bowditch in the third edition of his 

 " New American Practical Navigator," Tliis work was ori- 

 ginally jjuljhshed in America in tlie year 1801 ; Inil tiie third 

 edition, here alluded to, a])j)ears tvithoid a date: and, as it is 

 not kuouu whether the table was inserted iu tlie first and se- 

 cond editions, jio correct inference can be drawn as to the time 

 when this jntlhod was first adoptetl l)v the American navy. 



'J'lie 



