304 W. A. Rogers on Variability of Personal Equation. 
portance, inasmuch as astronomical observations are usually 
carried far into the night. 
IV. Does hunger affect the value of the personal equation ? 
Normal state minus a state of hunger. 
June 27-8—_—-0275 
—'039 
There is thus a decided and quite regular change, the mean 
being —-032s, 
V. Does the mental state of the observer have any influence on the 
personal equation ? 
Normal state minus a state in which the observation is asswmed too late. 
27 —'038 
I have already remarked that I obtained the first knowledge 
of the value of my personal equation, Nov. 21, 1867, and that 
a tendency to reduce its value, Since constancy in value is mor 
desirable than this reduction, which is uncertain and variable, 
it may not be best for an observer to have ® 
owledge of his personal equation, J ought to remark, howe — 
1.  abectation of having my suspicions on this poll) 
confirmed, may have had somet ing to do with the results 
found, though T endeavored to free my mind from every bias” 
except the single one assumed. i 
