Observations on the sun were also made each day, in case the unsettled weather 

 should not permit the use of stars the following night. It has, however, been thought 

 better not to include the sun observations in the actual rate determinations, as a fixed 

 mark is used with these. They, however, give rates not far from those given by the 

 star observations alone. 



In consideration of the fact that the comparison of the personal errors of myself 

 and Mr. Adams were made in a totally different manner to that used in the star observa- 

 tions I have thought it wise to neglect the observation by myself on the 19th, and to 

 apply to Observatory clock (1) a uniform rate of +1-02 sec. from the 18th to the 20th. 



In either case, the mean value of the mean pendulum comes out the same, but 

 much more consistent results are obtained if my observation is neglected. 



The analysis of the time observations is given in Table L. 



Flexure. The correction for flexure was three times observed and gave the values : 



Nos. 5 and 7. 

 19-4X10- 7 sec. 

 19-9 

 21-6 



No. 21. 



29-OX1Q- 7 sec 

 29-9 

 31-2 



20-30-4 



30-00-4 



The temperature was measured by No. 29110 in the dummy pendulum resting on 

 the cork base. Its error has been taken as 0-07 C. at the temperature of 15 C. 

 and this correction applied throughout. The temperature in the pendulum room 

 remained very constant with a maximum variation from 14 -92 to 15 -22 C. The 

 greatest change in temperature during the course of any single swing was 0-04 C. in 

 35 minutes, so that no correction for lag needs to be applied. The temperature gradient 

 was about 0-5 C. per metre. 



The Observatory standard " Barometer, Cooke 2155 " was used, and was read 

 once for each set by a single pendulum. The hygrometric correction was applied from 

 the readings of a pair of wet and dry bulb thermometers. 



The rate of " S.C." was deduced from comparisons with Observatory standard 

 ( 1 ) at the time of star observations, and may be put down in the following manner : 



70 



