I 



History of Astronomy for the Year 1803. 211 



by my nephew Lalande, gave as the mean for 1800 23° 28': 

 this is the result of more than 1 500 observations ; but it 

 supposes the height of the pole to be 48° 50' 13" instead of 

 14", and the latter supposes the refraction of Bradley in- 

 creased by l". Bv these means he makes the winter to 

 agree with the summer solstice, between which there was a 

 difference of 7 or 8". The bad weather did not permit him 

 to observe the winter solstice with the circle which I caused 

 to be constructed by Lenoir for the observatory of Palermo. 

 The astronomers Bradley, Lacaille, and Mayer, found for 

 1750 23° 28' 18-5"; the secular decrease, therefore, would 

 be 42" per century; and I prefer this result to that of the 

 equation of the sun produced by Venus, vv^hich would give 

 50". 



Dr. Maskelyne found with a mural quadrant at Green- 

 wich 23° 27' 57"; but the English have not yet adopted 

 our repeating circles, with which one may be certain to a 

 second, and with which no errors in the divisions are to be 

 apprehended. 



Piazzi, at Palermo, found 23° 27' bQ-G" with an excel- 

 lent circle by Ramsden, but not a repeating circle. 



The Academy of Berlin has still proposed, for 1806, the 

 determination of the obliquity of the ecliptic, both by theory 

 and observation. The details are contained in the Moniteur 

 of November the first. But little remains to be done in that 

 respect. 



The refraction still contains a doubtful element; it is the 

 correction required bv the density of the atmosphere. 



M. Gay has presented to the Institute an interesting me 

 moir on this subject, and there is one in the Transaction?^ 

 of the Society of Manchester: an extract of it has been 

 inserted in the BllUotkcque BrUannlque published at Ge- 

 neva. 



The measure of a degree of the earth in Lapland, which 

 M. Melanderhiclm has procured for us, and the calculations 

 it required, were transmitted to us in the month of April 

 by Messrs. Svanberg, Overbom, Holmquist, and Palander : 

 they have found the degree to be 57137 toises. That found 

 by Maupertuis, Clairaut, Camus, Lemonnicr, Outhier, and 

 Celsius, in 1736, was 57405, which is greater by 208 toises. 

 This enormous difference was suspected. The degree of 

 Lapland was at variance with all theory and with every 

 other measurement : it gave to the earth too great a flatten - 

 ine; whereas the new degree gives xiitj which is not much 

 diSerent from the -/^-^ giyen by the new meridian of France, 

 O 2 compared 



