INTRODUCTION. 



XIU 



The barometer, which was a Marine Barometer, Kew pattern, was placed in the Observatory, 

 with its cistern 18 ft. above the level of the lake. It was hung in a good light, and screened 

 from the sun, and from the fire. It appeared to be in good order, and its performance was 

 quite satisfactory, as far as could be judged by comparison with the aneroid. The instru- 

 ment was not brought back to England for re-verification on account of the great probability 

 of damage on the journey home, and had it been found to be out of order on receipt there 

 would have been no possibility of determining whether the injury had been received before 

 or after leaving Fort Rae. It has been already explained that one barometer was broken on 

 the way out. 



The dry and wet bulb mercurial and spirit thermometers were placed in a zinc screen, of 

 Professor "Wild's pattern, with their bulbs 5 ft. 10 ins. (1 -77 m.) above the ground. During 

 the winter this height was reduced by 8 or 9 ins., owing to the accumulation of snow. The 

 maximum and minimum thermometers and a hair hygrometer were placed in the same screen. 

 In February a wooden roof was added to protect the screen from the rays of the sun. 



The rim of the rain gauge was kept at a height of 1 ft. (-32 m.) above the surface of the 

 ground or of the snow. The solar radiation thermometer was placed vertically, with the bulb 

 uppermost, and 5 ft. 8 ins. (1 '72 m.) above the ground. 



The terrestrial radiation thermometer was supported horizontally by two forked sticks, 

 with its bulb 1 inch above the surface of the soil. During the winter it was placed on the 

 surface of the snow, as also was an ordinary spirit thermometer, whose readings have 

 been recorded hourly in clear and calm weather for comparison with the air temperature at 

 the time. 



The earth thermometers were fastened to a lath at intervals of 1 ft., and placed in a copper 

 tube, which was sunk vertically in the ground. As the surface bad a slope of yV; to 

 the S.W., and, as it was cleared of vegetation, it no doubt received more of the sun's heat than 

 a normal portion of the earth's surface in this latitude. There was but little choice of position 

 owing to the rocky nature of the soil, a circumstance which prevented observations of 

 temperature being made at a greater depth than 4 feet. At first the thermometers were 

 placed in the tube without any packing, but as the weather became colder, they were so 

 rapidly aS'ected by the temperature of the external air on being withdrawn from the tube that 

 there was not time to record their readings before they began to change ; they were therefore 

 surrounded with strips of fur (on the 4th November), and thenceforward the readings were 

 much more regular. The fur, however, proved attractive to some beast of prey, probably a 

 carcajou (wolverine), which on the night of the 11th January managed to extract the ther- 

 mometers from their tube, breaking them all. The observations were continued with other 

 thermometers, which were coated this time with cotton wool, and no further interruption 

 took place. 



The position of the Observatory rendered it difficult to find a good position for the 

 anemometer, on account of the hill to the north-east. Winds from this quarter were, 

 however, rare, and the anemometer was well exposed to the prevalent winds, which were 

 north-westerly and south-easterly. The estimated force by Beaufort's scale has been used 

 in the reductions, a comparison having shown a close agreement with the anemometer 

 readings. An anemometer was placed on an island in the lake, but it was so frequently 

 stopped by snow drifting into the works that no use has been made of its readings. 



In the winter it was found necessary to surround the meteorological instruments with a 

 fence, to prevent the attention of the observer on duty bemg distracted by the possible visit 

 of a wolf. These animals, which are here large and formidable, often roamed at night 

 amongst the buildings of the post. 



