37. 



ON THE CHANGE IN THE ADOPTED UNIT OF TIME. 



[From the Monthly Notices of the Royal Astronomical Society, Vol. XLIV. (1884).] 



THE December number of the Monthly Notices contains a paper by 

 Major-General Tennant in which the author arrives at conclusions which 

 appear to him to confirm Mr Stone's views respecting a change in the 

 unit of mean solar time. In reality, however, those conclusions are quite 

 consistent with my own as given in the same number of the Monthly Notices, 

 (see p. 259 above) and not at all with Mr Stone's. 



According to Major-General Tennant (Monthly Notices, p. 43), the factor 

 by which the tabular mean motions should be multiplied in consequence 

 of the change from Bessel's to Le Verrier's determination of the ratio of 

 the mean solar to the sidereal day is what he calls 



Sidereal Seconds in Le Verrian Mean Day 

 Sidereal Seconds in Besselian Mean Day 



Now, if n be the Sun's mean motion in a mean solar day as deter- 

 mined by Bessel, the sidereal seconds in a mean solar day will be 



But if n + Sn be the Sun's mean motion in a mean solar day as determined 

 by Le Verrier, the sidereal seconds in a mean solar day will be 



86400 X - 360 



