CHRISTCHURCH, 1910. 



Latitude = 43 31' 50" S. Longitude == 172 38' 9" E. 



OBSERVATIONS ON EAST PILLAR OF ABSOLUTE MAGNETIC HUT (BUILT ENTIRELY OF WOOD). 



Height above sea-level, 25 feet. 



Clock rate. The clock rate of the sidereal clock lent to the Expedition, and here- 

 after denoted as " S.C.," was determined by observation of stars at meridian passage by 

 means of the small portable transit instrument, set up on a concrete pillar erected in the 

 Observatory grounds by the kindness of Mr. Skey. The fixed mark was furnished by a 

 small light on a wooden post well planted in the ground towards the south. The clock 

 was hung on the wall of the absolute hut some 40 yds. away from the instrument. In 

 order to hear the beat of the clock, the coincidence apparatus was brought out close 

 to the transit instrument with a long lead of flexible wire at the commencement, and 

 replaced under cover at the close, of each set of time observations. The disadvantage 

 of this arrangement was, of course, that no method was provided for determining to 

 which seconds and to which minute the beats referred. To settle this point, another 

 observer, as the star became due, would betake himself to the clock, note the minute 

 and start to walk slowly towards the transit instrument, meanwhile counting the seconds 

 aloud. As soon as he was clear of the building, the coincidence ticks became audible, 

 and in this way the correct time of passage was estimated to one-tenth of a second by 

 ear and eye in the usual manner. 



The observed rates were very discordant and gave in the mean- 

 November 17th-l 8th .. .. 0-30 sec. gaining, + 04 from 3 stars. 

 18th-19th .. .. 1-03 0-32 



The reason for the discordance of these results may be put down largely to the 

 limitations of the transit instrument. It was loose in every joint and the collimation 

 constant changed at every touch of the hand. For this reason, and for the additional 

 one that the clock and the pendulum apparatus in the small wooden hut were subject 

 to huge variations in temperature, very little reliance can be placed on the results. 



The temperatures recorded by the thermometer in the pendulum case during the 

 observation on November 18th, 1910, varied from 13 -31 C. in the morning to 26 -38 C. 

 in the afternoon a range of 13 between 9 a.m. and 5 p.m. 



Flexure. The observations for flexure were made on three occasions and gave 

 the following values : 



Nos. 5 and 7. No. 21. 



G9-4X10- 7 sec, 92- 1 x 10~ 7 sec. 



09-7 98-0 



72-3 91-7 



Mean 70-5xlO- 7 sec 93-9x10 "' sec. 



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