14 SCOTT. — METEOROLOGICAL INSTRUCTIONS. 



Reference to the maps of the magnetic elements accompanying 

 this memorandum will show that these changes of declination do 

 not arise from magnetical causes, as the direction of the needle 

 with reference to the north magnetic pole remains the same and 

 the inclination and force values remain comparatively unaltered. 

 These compasses should be preserved with care, to ensure accuracy 

 in the observations, and in aid thereof, small extra travelling com- 

 passes (fitted so as to be corrected for the declination if necessary), 

 are furnished to perform the rougher work of the steering compass 

 for sledge parties or travellers. 



The several constants, index and temperature corrections of 

 the various instruments have been determined at Kew and the 

 Admiralty compass observatories, and will be furnished to the 

 Expedition. 



IIL—METEOROLOGY. 



1. Meteorological Instructions. By Robert H. Scott, 

 F.R.kS., Director of the Meteorological Office. 



The meteorological observations to be made during the Arctic 

 Expedition will, in the main, be similar to those made on any 

 voyage, and accordingly the instructions for the management of 

 the instruments and for taking the readings will in great measure 

 be identical with those furnished to observers at sea under ordi- 

 nary circumstances. The latest copy of these instructions is con- 

 tained in the Report of the Conference on Maritime Meteorology 

 in 1874, of which copies are furnished to the Expedition. 



There are, however, certain points which require special notice, 

 and particularly so as it is hoped that for a considerable period 

 of time observations will be taken regularly at fixed stations or even 

 on shore. 



Hours of Observation, — In Sir J. C. Ross's expedition to the 

 Antarctic regions the observations were taken hourly, but the 

 expedition was always at sea, so that the number of available 

 observers was never reduced by sledging expeditions, &c. 



It is certain that observations will be taken as frequently as 

 practicable on the present occasion, but it must be remembered 

 that in all cases quality of observations is of much greater impor- 

 tance than quantity, so that if it be impossible to give correct 



pole, the direction of the magnetic meridian is determinate, but that of the 

 geographical meridian is indeterminate, every different meridian, as defined 

 by its longitude from Greenwich, having its corresponding variation of the 

 compass. At all points near the geographical pole the statement of the 

 variation of the compass should be accompanied by a statement of the longi- 

 tude of the meridian to which the variation is referred. 



