Royal Astro7i07nical Society. 67^ 



This statement gives only an imperfect idea of the value of the 

 instrument. When the moon passes from one to four hours before 

 or after the sun, there are thirty-four observations with the altitude 

 and azimuth, and not one with the transit and circle*. It is not 

 necessary to point out the immense utility of these results in the 

 lunar theory, or to geography and navigation, which dejjcnd on lunar 

 observations for their fundamental determinations!. The results of 

 the observations, as reduced to the state of apparent errors of tables 

 in R.A. and N.P.D., appear very good; perhaps a little, and but a 

 little, inferior to those of the meridional instruments. 



Throughout the year 1847, the new form of star- reduction pro- 

 posed by Mr. Airy as a substitute for Bessel's (see M. Notices, 

 vol. vii. p. 189) has been used, and it has been found convenient. 

 At present the assistant! are employed in collecting all the star-ob- 

 servations in 1842-47, for the purpose of forming another grand 

 catalogue reduced to the epoch 1845. The Astronomer Royal pro- 

 poses to give in this catalogue the star-constants e,f,g, h, I; e\f', 

 g', h', I', and also, for a few years, the day-constants E, F, G, H, L, 

 which are required by his method. 



The reduction of Fallow's Cape Observations was commenced 

 some time ago under the direction of the Astronomer Royal. This 

 was interrupted by the work incident to the completion of the lunar 

 reductions, but it will be resumed in a short time. 



The ledgers of star- observations and occasional star- catalogues 

 found in Maskelyne's observations have been fairly written out. 

 Mr. Airy submitted to the Visitors the propriety of printing these 

 reductions, and also suggested whether it might not be advisable to 

 take some steps of calculation with respect to Bradley's observations 

 anterior to 1750. 



In June last, the printing of the volume for 1846 was nearly 

 finished, and the volume for 1847 was commenced. 



Edinburgh. 



Professor C. P. Smyth has been hitherto engaged in reducing and 

 editing the observations of his lamented predecessor, and in exami- 

 ning and repairing the defects of his instruments and observatory. 

 The meridian buildings are reported to be now in perfect order, and 

 the instruments in a satisfactory state. It will be remembered that 

 Professor Smyth has undertaken to determine the places of stars 

 compared with the small planets and comets in extra-meridian ob- 

 servations, and when he is fully prepared (of which due notice will be 

 given), it will be desirable that he should have early information of 



• The working of this instrument is considered to absorb one assistant 

 and one additional computer. 



t When the limar tables are made to satisfy the places of the moon 

 given in the 'Reduction of the Greenwich Lunar Observations,' and are 

 further corrected by observations made with the azimuth and altitude in- 

 strument, well-observed moon-culminations will not require corresponding 

 observations, and occultations will yield trustworthy results wherever they 

 may be observed. 



F2 



