DEPARTMENT OF MERIDIAN ASTROMETRY. 203 



Albany +0?0135 cos (IS^" 6" -G. M. T.) 



Greenwich +0.0141 cos (13 37 -G. M. T.) 



Cape +0.0088 cos (13 19 -G. M. T.) 



Pulkova +0.0084 cos (11 31 -G. M. T.) 



Mean +0.0102 cos (12 53 -G. M. T.) 



The comparatively close agreement in the results raises the question 

 whether the diurnal term may not be a function of the absolute instant 

 of time and not merely of the local mean time. If the diurnal term of 

 the Melbourne Observatory could be determined and should accord 

 with the results already obtained, the subject would warrant an 

 extensive investigation. 



It might be remarked, in passing, that in the treatment of the 

 Albany and San Luis observations for diurnal term, several combina- 

 tions of results were employed. The corrections were combined 

 according to observers, clamp, seasons, and years. Also, during the 

 period 1907-1913, the Riefler clock ran unsealed, with no effective 

 temperature control, while during the period 1915-1918 the clock was 

 sealed and the temperature of the clock-room was practically constant. 

 The diurnal term was evident, no matter what the arrangement 

 might be; therefore there can be little doubt concerning the reality of 

 the diurnal term. It only remains to determine the nature and cause 

 of the variation. 



PERSONALITY IN THE ESTIMATION OF TENTHS. 



The investigation by Dr. Albrecht on personality in the estimation 

 of tenths was undertaken with a view to its bearing upon the design 

 of a special measuring instrument for which extensive use is con- 

 templated. Information regarding a proper balance of speed and 

 accuracy of measurement was sought. 



Among the more general results obtained, it was found that person- 

 ality in the estimation of tenths is a very definite thing, rendering it 

 possible to apply corrections to the measures within certain limiting 

 conditions. The nature of this form of personality was discussed for 

 23 observers, covering various intervals of time, in one case 39 years. 

 It was established that the epoch is the important consideration in 

 discussing a personal scale. Individual scales may vary, but the 

 variation is gradual and generally progressive. The personal scale is 

 essentially constant during short periods of time, generally for a few 

 months. Fatigue during a continuous 5-hour period of obser\dng 

 produced no appreciable change. The zero tenth is almost universally 

 favored, while no tenth is as generally neglected as the zero is favored. 

 Most of the curves representing personal scales are essentially sym- 

 metrical with respect to 0.0 and 0.5, though a few show an unbalanced 

 preference for or neglect of one or two of the tenths. Most observers 

 have a definite tendency to estimate an index too close to the nearer 

 of the two adjacent scale-rulings, the degree varying quantitatively 



