meter. During tin- winter months the therm. miftcr M.metimcs gave readings below the freezing-point of 

 mercurv*; l>nt it w;is or. -asionally frozen, and when this was the case the temperature shown l>y the spirit 

 minimum thermometer at the time of observation is entered in this column as the temperature of the air. 

 The mean of the In-hourly observations is given each day at the foot of the column. 



Column 6. Wet Temperature of the "wet" bulb in degrees Fahrenheit, obtained from another 

 mercurial thermometer placed by the side of the dry bulb, and at the same height above the snow. 

 Throughout the stay of the "Discovery" in her winter quarters, water in the open air was invariably 

 frozen. The muslin with which the bulb of the thermometer was covered was therefore allowed to hang 

 a little below the bulb and was kept coated with ice, the rule being to put a few drops of water upon it 

 from a rubber syringe at each time of observation, immediately after the thermometer had been read, care 

 being taken, however, to keep the coating of ice as thin as possible. The mean of each day's wet-bulb 

 observations is given at the foot of the column. Occasionally the wet-bulb thermometer indicated a higher 

 temperature than the dry-bulb. In such cases, if the difference did not exceed one degree, the reading is 

 given, but when the difference was greater than one degree the wet-bulb reading has been omitted. 



Column 7. Unscreened Thermometer. The temperature in degrees Fahrenheit by an ordinary 

 mercurial thermometer placed in an upright position above the screen in which the dry- and wet-bulb 

 thermometers were hung. Up to March, 1 903, the thermometer was attached by india-rubber bands to 

 one of the posts to which the screen itself was fixed, but from that date onwards it was supported vertically 

 by strips of brass fastened to the top of the screen, the height of the bulb above the screen being 2 inches, 

 and its distance back from the front edge of the screen 4 inches. The thermometer was therefore fully 

 exposed to the air, and to the sun's rays whenever the sun was shining. The screen was painted white. 



Column 8. Wind Direction and Force. The direction of the wind was obtained from a vane erected 

 upon a post forming one of the supports of the thermometer screen. The height of the vane above the 

 snow varied with the depth of snow between 15 feet and 8 feet. All the wind directions given for Winter 

 Quarters have been corrected for magnetic variation, and are therefore true. The force of the wind was 

 estimated by BEAUFORT'S Scale of Thirteen Points (0 to 12), in which indicates a calm and 12 a hurricane. 



Column 9. Wind Velocity by Cup Anemometer. The mean velocity of the wind in statute miles 

 per hour as recorded by a small cup anemometer, the cups of which were 3 inches in diameter and the 

 arms 6J inches long. This instrument was exposed upon another of the upright posts carrying the 

 thermometer screens, the cups being at the same level as the vane. The dials were read every two hours, 

 and the reading has been divided by 2 to get the average hourly run of the cups in the interval. Before 

 it left England the anemometer was tested at the Kew Observatory of the National Physical Laboratory, 

 and found to give approximately the same result as the large, " Kew pattern," anemometer. The readings 

 of that instrument have to be corrected for the factor, and reduced in the ratio 2 '2 to 3 - to get results in 

 statute miles per hour, and therefore the readings of the small instrument have been similarly dealt with. 



Column 10. Wind Velocity by Pressure Tube Anemometer. The actual velocity of the wind in 

 statute miles per hour at the time of observation as indicated by a portable "sight-indicating" pressure- 

 tube anemometer. This instrument was attached to the side of another of the posts carrying the thermo- 

 meter screens, and was connected by 5 feet of composition tubing with a vane placed at the top of the post 

 10 feet above the snow level. It was read every two hours when the other observations were made, and 

 the oscillation of the fluid in the tube, denoting the variation in the wind force, was observed during a 

 short interval. Thus the entry "15-20" indicates that whilst the observation was being made the 

 velocity of the wind varied between 15 miles and 20 miles per hour. 



Column 11. Weather. The weather at the time of observation indicated by the Beaufort notation, or 

 by the International weather symbols, as follows : 



* Sec Note on this subject by Dr. J. A. HAKKKE, p. 15, 



