4 INTRODUCTORY NOTE. 



light for the sensitive paper on the recording drum. This accounts for the loss of a few days' records 

 during the first year. Nor was the lamp successful in keeping a uniform temperature and giving out a 

 fair proportion of heat for the amount of oil burned. During the second year the lamp was dispensed 

 with, and the house was entirely buried under snow, and although at times the temperature within was 

 low, viz. : - 30 F., its diurnal variation was seldom large throughout the 24 hours. 



General. During the first year the curves are finer and sharper than during the second, on account of a 

 more sensitive bromide paper being employed, and, consequently, a smaller light-slit. The magnetograms 

 were usually developed once a week by means of ortol-soda developer, which has the advantage of being 

 exceptionally clean to use and gives rich dark tones to the curves. 



Towards the end of the second year the supply of recording paper became very short, and from the end of 

 September, 1903, had to be distributed equally over the subsequent months, amounting to about 4 days in 

 each month. This is the only serious break in the two years' record. In all there are records for about 

 600 da\ <. 



My thanks are due to the New Zealand Government for the courtesy in placing the Christchurch 

 Observatory at our disposal, to Dr. COLERIDGE FARR and Mr. H. F. SKEY, of that Observatory, for their 

 valuable assistance, to Mr. P. BARACCHI, Government Astronomer of Victoria, and to Dr. CHARLES 

 CHREE, F.R.S., who has been so closely associated with the " Discovery " magnetic work from the 

 beginning. 



