INTRODUCTORY NOTE. 



BY 



L. C. BERNACCHI, F.R.G.S. 



THE self-recording Magnetographs supplied to the National Antarctic Expedition were of the delicate 

 transportable type devised by the late Professor VON KSCIIKMIACKN and made by the firm of O. TOEPKKU, 

 of Potsdam, Germany. They were received at the National Physical Laboratory, Surrey, England, in 

 August, 1901, after the departure of the "Discovery." 



The set consisted of three instruments, viz., a Declinometer, a Horizontal Force Magnetometer, and a 

 Vertical-Force Magnetometer, with a self-recording photographic apparatus. No instructions were supplied 

 by the makers, and as they were of a type absolutely strange in this country, some little difficulty was at 

 first experienced in erecting and adjusting the instruments. 



Dr. HARKER and Mr. F. E. SMITH, of the National Physical Laboratory, succeeded in adjusting them 

 satisfactorily, and had them recording for a few days before my departure from England by mail boat to 

 join the " Discovery " in New Zealand. 



The Horizontal-Force instrument proved to be considerably more sensitive than the Kew form of 

 differential magnetometers a difference which was due to the fineness of the quartz suspension fibre 

 employed. Unfortunately, it was not discovered until too late that the boxes of spare quartz-fibres 

 supplied contained even finer threads than that already in the instrument. 



On arriving at Melbourne, at the end of October, 1901, the instruments were taken to the Government 

 Observatory and erected on a wood bench in a cellar. From November 1st to November 10th they 

 worked in a satisfactory manner. They were subsequently conveyed to the " Discovery " at Lyttelton, 

 New Zealand, carefully secured in my cabin, and were not again removed until the ship reached her 

 Winter Quarters in McMurdo Sound in February of 1902. 



Winter Quarters. The Winter Quarters were situated in latitude 77 50' 50" S., longitude 166 44' 45" 

 E. of Greenwich, and to the south of a narrow peninsula extending in a south-west direction from the 

 base of an island formed by Mounts Erebus and Terror. The " Discovery " remained frozen-up in her 

 Winter Quarters from February, 1902, until February, 1904. 



Observatory Site. The spot selected for the Observatory, although the best available, was hardly an ideal 

 one for magnetic observations. From a magnetic point of view, an observatory of this kind should be 

 placed in a position undisturbed by the presence of magnetic rocks ; but it would be difficult to find such 

 an undisturbed locality in Victoria Land, unless it were on the surface and near the seaward edge of one 

 of the extensive ice-floes, far from the actual coast line, such as the Great Ice Barrier. 



Geological Formation. A description of the Geological Formation in the neighbourhood of the station 

 will be found in " Physical Observations," pp. 129-130. 



Observations for Local Attraction. A comparison of the results of absolute observations made in the 

 Magnetic Hut with some taken on the ice in McMurdo Sound at a considerable distance from land will be 

 found in " Physical Observations," p. 134. 



The site selected for the houses was a low and fairly level piece of rocky ground close to the 

 extremity of the peninsula, and at a distance of about 300 yards from the ship (.<? Frontispiece). 

 The peninsula is about 10 miles long by a mile broad, and has an average height of 600 to 

 700 feet, although the extremity where the Observatories were placed was only 30 feet above the mean 

 sea level. 



Observation Houses. The Observation Houses were constructed of large asbestos slates, screwed on to 

 the outside and inside of a wood framework. The larger of the two used for the Variation House 

 was 11 feet 6 inches by 11 feet 6 inches, and 6 feet 8 inches high. 



Although, perhaps, small log houses would have been more suitable, they certainly would not have 



B 



