204 CARNEGIE INSTITUTION OF WASHINGTON. 



with the widths of the lines. When the seale-ruhngs and index have a 

 width of 0.2 of a scale-interval, tenths can be read with practically no 

 error. /\jnong the most gratifying results obtained is the indication, 

 derived from tests, that readers without previous experience in the 

 estimation of tenths can acquire and retain a nearly true scale of tenths 

 with a small amount of drill through the use of practice scales. On 

 account of the influence which the widths of lines have upon the estima- 

 tions, practice scales should always be similar to the scales employed 

 in the regular work in respect to the comparative widths of lines and 

 scale-interval. 



STELLAR WAVE-LENGTHS. 



Dr. Albrecht has continued his study of stellar wave-lengths. As a 

 part of the more general program, the stellar wave-lengths have been 

 computed for the individual lines v/hich were employed for the deter- 

 mination of the radial velocities published in detail in Publications of 

 the Lick Observatory, Vol. IX. 



REDUCTION OF OBSERVATIONS. 



Mr. Roy has found it advantageous to employ most of his efforts 

 in supervising the reductions of the San Luis zenith distances, so little 

 has been accomplished upon the Albany zenith distances. Mr. VaiTium 

 has devoted his time to the preliminary reductions of the Albany 

 right-ascensions. The San Luis observations of the five obsei-vers 

 have been collated on cards. Considerable tune has been employed 

 in applying the concluded systematic con-ections for the separate 

 observers to the final places as entered on the cards. One set of com- 

 putations upon the precessions has been completed and the duplicate 

 set is nearly finished. The computation of the secular variations is 

 well under way. Many of the discordances among the observations 

 have been investigated, but considerable work remains to be done 

 to insure freedom from errors of computation and collection. 



PREPARATIONS FOR THE GENERAL CATALOGUE. 



The preparations for the general catalogue have continued under 

 the supervision of Mr. Roy, the details of the comparison of catalogues 

 with the standard system being largely performed by Mr. Jenkins 

 and Miss Buffum. For the catalogues listed in the preceding annual 

 report little remains to be done, with the exception of a definitive 

 revision of the weights. Several catalogues have been added to the 

 previously published list : 



32. Karlsruhe 1890 0° to -8°. 



33. Albany Zones 1900 -20° to -41°, -2° to +1°. and fundamental. 



34. Cape 1900 Fundamental. 



35. Konigsberg 1900 Largely zodiacal. 



36. Konigsberg 1905 Fundamental. 



37. Pulkova 1905 Fundamental. 



