444 On determining the Longitude 



of any ulillly whatever. The author's papers in the Phi* 

 losophical Transactions are hitherto free from this aflVcta- 

 lion, and we hope he will see the propriety of using only 

 pure potash in future in these Elements., Sir Humphry is 

 no less distinguished for the subliojity and beauty of his 

 language than for his unparalleled discoveries: consequently 

 liis example in such a case must naturally become the 

 JUS ct norma loqueiidi. 



We understand that translations of this volume into 

 Portuguese and Spanish have already been undertaken by 

 gentlemen very well (jualiiied for the arduous task. 



LXXVIIT. An Account of a Scries of Observations made 

 on the Distance of the Sun and Moan for determining the 

 Longitude of ike Place of Observation^ with Remarks on 

 the best Method cf makuig such Observations, with their 

 Calculation^ Deductions, &c. By Mr. FiitMiNGER, 

 iate Aisistaut at the Ruyul Observatory, Greenwich. 



JLt being generally understood, that to determine the 

 longitude of a place-by the lunar observations, it is requi- 

 site to have three scj^arate observers, viz. one to observe 

 the moon's altitude, another the sun's, and a third to lake 

 the distance between the limbs of the sun and moon, or 

 the moon and a star, 1 was induced to make a set of observa- 

 tions for determining the longitude of my place without 

 anv such assistance, it having frequently occurred to me 

 that a series of observations might be made by only one 

 observer, which would require bul little additional labour in 

 the calculation to that which is necessary when three se- 

 parate obsers'ers are emploved, and the result of the trial 

 has fully confirmed my conjecture. 



The following observations, from whence this conclusion 

 was drawn, have not the best possible arrangement; it was 

 readily seen in making the calculation, that nuich of the 

 trouble of reduction might have been avoided by a different 

 method (*f taking the observarions ; but what has been done 

 will, it is hoped, be sufficient to show the value of the 

 means which have been emploved. 



The weather at the time of the year when these observa- 

 tions were made, is but seldom favourable in I^ondon, and it 

 was owinii chieflv to this circumstance that diflerent sets oF 

 observations on ihe same day v.ere taken, and which it was in- 

 tended to repeat tdl thenun)her of mdependent sets amounted 

 to trn, by taking two or three sets each day ; but the fine 



weather 



