GENERAL PHYSICS 



[ SIMPSON AND WRIGHT] 



BY CHARLES S. WRIGHT, B.A. 



THE field covered in pure Physics by the Expedition was by no 

 means a small one. It may be conveniently be divided as follows : 



(a) Magnetic observations. 



These consisted in continuous photographic records by Esch- 

 enhagen magnetographs of the elements NS. (astronomical) 

 force, E.W. force, and vertical force. These instruments were 

 placed in a cave dug into an ice-drift, a couple of hundred feet 

 to the south-west of the hut at Cape Evans. This furnished the 

 highly desirable advantage of a constant temperature condition, 

 important in that the sensitiveness of the instruments is depend- 

 ent upon temperature. The light in the cave was furnished by 

 a small electric lamp run from accumulators in the hut. Time 

 signals were recorded on the trace every two minutes by means 

 of a clock fitted with electric contacts, kept also in the hut and 

 compared daily with the standard chronometer. 



The programme of magnetic work included ' quick runs ' on 

 international term days. ' Quick runs ' are obtained when one 

 moves the photographic paper at a much greater speed than 

 usual, so as to have a more open time-scale. These were carried 

 out at the same times by all magnetic observatories, in the hope 

 that the comparison of traces would give definite information 

 regarding the origin of magnetic storms. 



Magnetic storms, though frequent, are not of hourly occur- 

 rence, and it is a matter for congratulation that one of our 

 largest storms (also recorded by Webb's instruments with Maw- 

 son) occurs during the course of a quick run. 



In addition to almost complete traces furnished by the mag- 

 netographs, absolute observations were undertaken once a week 

 for standardisation of the traces, while observations for sensi- 

 tiveness of the magnetographs were carried out once a month. 



Observations of stars or sun, for time signals and for rating 



