1826.] making a minute Survey of the Heavens, 131 



Now it is only required to subtract the precession from 1800 

 to 1825, which can be done by a small table with double entry, 

 which any one may compute for himself. 



For the stars in the Histoire Celeste M. Schumacher's tables 

 will in the same manner enable us to reduce the observations at 

 once to the epoch of 1800 ; so that it will not even be necessary 

 in this case to compute the precession. 



I hope, Sir, that these reductions which require only the addi- 

 tion of three numbers, will not appear to you either too long or 

 too complicated. They comprehend at the same time all the 

 corrections of the instrument, and of the apparent place ; and a 

 computer ever so little versed in such calculations will not find 

 the application of it troublesome or tedious. The degree of 

 accuracy is as great as may be attained by any other means ; 

 since nothing indeed has been neglected in it.^ 



It is the desire of the Academy that each astronomer should 

 himself make these reductions, and that he should then place 

 these observed stars on his chart ; distinguishing (in the manner 

 above mentioned) those which have been once or twice observed. 

 This part of the work is in my opinion a great deal more diflS- 

 cult, and requires a more scrupulous attention than the compu- 

 tation, where the two columns of the values of k and d follow a 

 regular order, and the other two columns, k' and d% have never 

 much influence on the result. Each sheet will represent two 

 thousand observed stars at least; every one of which will have 

 its mode of delineation prescribed according to its magnitude 

 and the number of observations. It will not be possible to 

 commit this operation, which cannot even be easily verified, to 

 any other person than the astronomer himself; who, by putting his 

 name to the sheet, will render himself responsible for the accu- 



* [For the convenience and accommodation of those persons who are disposed to take 

 a share in this undertaking, the Astronomical Society have caused skeleton forms to be 

 printed, by means of which much of the trouble and risk of error attending the reduc- 

 tions will be saved. Any number of these forms may be had, by application to tiie 

 Secretary before the 1 st of January next, after which day the press will be broken up.— 

 Sec] 



K 2 



