THERMOMETRICAL OBSERVATIONS AT POINT BARROW. 163 
diameter, with a longitudinal opening through which it could be easily read ; 
this cylinder was kept in another of the same material which was painted 
white, seven inches in diameter, having a conical projecting roof, and a flat 
bottom, with numerous small openings in both, and a door opening like a 
common tin lantern: this again, with its door facing the north, was fixed to 
a stout stake, placed in the ice at a distance of 90 feet to the eastward of the 
ship. The arrangement so made was to protect the instrument from the wind 
and snow-drift, and from the influence of the sun, while admitting the easy 
access of air. To have placed it further from the ship would have been to 
put it in the way of natives, who might steal or break it; and as the ship’s 
hull was banked round with snow, and the prevailing winds came in from 
the N.E., it was thought the effect of her presence on the thermometer at that 
distance would be little or none. 
The position of the ship at Point Barrow was at the extremity ofa narrow 
point or spit of gravel, which at no part rose more than 6 feet above the 
ordinary sea-level, and about five miles distant from the mainland of the 
American continent. The coast trended on one side to the S.W., and on the 
other to the E.S.E., and was uniformly low and flat in the latter direction for 
150 miles, whilst to the S.W.there was no elevation near the coast approaching 
100 feet for a like distance. The mainland to the south had not been explored 
for more-than twenty or thirty miles, to which extent it was perfectly flat, 
and the natives described it as quite level for several days’ journey further, 
beyond which it became hilly, and far south mountainous. The climate, 
therefore, may be described as maritime or almost insular, and was not sub- 
ject to such extremes of temperature as the land. This was ascertained by 
the register kept by Capt. Maguire on a journey to the hunting-grounds 
during the coldest part of the year, the temperatures recorded by him being 
generally lower than those taken at the ship during his absence. In the 
summer the shooting-parties recorded higher temperatures on the land than 
were observed at the ship. 
The long polar night, or observed absence of the sun, was 69 days, from 
November to January; and the continued presence of the luminary in the 
summer, owing to refraction, embraced a period of 74 days. 
The calculations for the following Tables were made at intervals of leisure, 
and, though simple enough, were very tedious and open to error; but this, I 
think, has been successfully avoided by the various cross checks I used. 
Each mean in the first twelve Tables is deduced from the sums of the obser- 
vations, and in no instance from results already obtained. Some exceptions 
to this rule were made in producing the means of the two years combined. 
Taste I. gives the mean temperature of each day, and the mean of every 
10 days (or, when the month consists of 31 days, the last division is the mean 
of 11, and the latter portion of February is the mean of only 8 days); at the 
foot of the table the mean of each month, and at the foot of the page the mean 
temperature of the whole year, as ascertained from 8760 observations, those 
of the last 2! days of August having been intercalated as already stated. 
In this Table a remarkable rise of temperature will be observed before 
and after the winter solstice. The month of December set in cold the first 
10 days, giving a mean of 221 degrees below zero, whilst the second decade 
presented a mean of only half'a degree below that point ; and the last 11 days 
rose to 61. above it. The mean of December is little more than one-tenth of 
a degree lower than that of October, and is nearly 4 degrees higher than 
November: this was owing toa southerly gale which almost produced a thaw 
_ for 3 days at the winter solstice, and had the effect of driving the ice com- 
_ pletely off the coast, leaving nothing visible from the beach to the furthest 
M2 
