CHRISTCHURCH TKK.M I>AY OIISKK'VATIONS. 



APPENDIX A. 



Abstract of "Term Day" Observations at Christchurch Observatory, New /vuland, made and tabulated by 

 Dr. C. Coi.EiimcK, FAKR and Mr. H. F. SKKY, and their discussion by Dr. C. CHREK, r'.l.'.s. 



1. THE " Discovery," on her way to the Antarctic, called at New Zealand, and magnetic observations 

 were made at the Observatory at Christchurch. Dr. C. COLERIDGE FARR, who was then Director of the 

 Observatory, being anxious to utilise to the utmost the opportunities presented, arranged with Captain 

 SCOTT and Mr. BERNAOGHI for an extension of the programme of simultaneous magnetic observations laid 

 down before the Expedition left England. The original programme specified the 1st and the loth of each 

 month as " term days," during which hourly readings should be taken of the magnetic elements at all 

 co-operating stations. The programme further arranged that on each term day there should be a " term 

 hour," during which the values of the magnetic elements should be determined at 20-second intervals. 



On the first regular term day February 1, 1902 the term hour was to be 0-1 a.m., G.M.T. On each 

 successive term day the term hour was to be one hour later, so that on January 15, 1903, the twenty- 

 fourth regular term day, the term hour arranged was 11-12 p.m., G.M.T. This completed the regular 

 year, but four additional term days were proposed, viz. February 1 and 15 and March 1 and 15, 1903; 

 the term hours arranged for these were respectively 0-1, 1-2, 2-3, and 3-4 a.m., G.M.T. 



At observatories provided with self-recording instruments the readings were to be derived from the 

 curves, and, to admit of their being read at 20-second intervals, it was intended that the drums carrying 

 the photographic paper should lie rotated more rapidly than usual, twelve times the usual rate being the 

 speed commonly adopted. The extension of the programme thus arranged at Christchurch contemplated 

 that the magnetograph drums should be " quick run " during the whole term day. By altering the 

 position of the light after each revolution of the drum, six or eight hours' run were usually obtained on a 

 single sheet, but the mere alteration of the light entailed the presence of an observer, and several times, in 

 the absence of a second observer, Dr. FARR had to remain on duty during the whole 24 hours. Notwith- 

 standing the difficulties encountered, the revised programme was actually carried out at Christchurch, 

 quick runs being taken on 26 terms days from March 1, 1902, to March 15, 1903, inclusive. Some little 

 trace was necessarily lost when the light was being moved and when fresh paper was being put on, and 

 occasionally an hour or two's record is lacking, e.g. from 10 to 12 p.m., G.M.T., on September 15, 1902. 

 Declination trace was lost for one whole day, November 15, 1902. Everything considered, however, the 

 loss of trace is remarkably small. 



The extended scheme proved impractical >le in the Antarctic. Still, quick runs were taken during 

 several hours of most term days. This was so far fortunate as a mistake had somehow crept into the 

 Antarctic ' Manual,' which made each term hour 12 hours later than it should actually have been, and the 

 observer, Mr. BERNACCHI in the absence of any information to the contrary naturally supposed the 

 ' Manual ' to be correct. Thanks to the extended programme, there were three term days on which the 

 quick run made in the Antarctic covered at least a part of the real term hour, though on one of these 

 occasions the part thus covered is but short. 



2. The original programme which originated in Germany, but was approved by the Advisory 

 Committee of the British Expedition specified certain forms on which term-hour observations should be 

 entered. Thus, taking the case of the Horizontal Force, the actual curve readings were to occupy one 

 column, the converted values a second, the temperature corrections a third, the last column giving the 

 finally corrected values of the ordinates in absolute measure C.G.S. The absolute value answering to 

 zero ordinate, with particulars of the scale values and of the formula for the temperature corrections, were 

 to be given on a separate page. The form for each term hour provided for 180 entries under each of 10 

 separate columns. Dr. C. C. FARR and his successor at Christchurch, Mr. H. F. SKEY, applied the 



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