486 
NATURE 
more frequently takes place in_ rainy weather—July, August, 
and sometimes September: but I never examined them particu- 
larly excepting one, which we came near being buried by in 
camp. This was about August 15, 1876. By a pole, I found 
the bottom of the slide frozen hard, a grey clay and gravel mixed, 
from where the earth broke off was not over 6 feet. The surface 
soil sandy. Some way back from the river bank the country is 
muskeg more or less, and by removing the moss by hand we came 
to hard frozen ground in August.” The sentence printed in 
italic is somewhat ambiguous. It is understood to mean that 
the bank was not much more than 6 feet high, and was hard 
frozen at that depth ; the depth to which the frost extended is 
therefore unknown. 
5. Lat. 64° 20’ N., long. 124° 15’ W., on Mackenzie River. 
—The face of acliff from which a recent land-slide had occurred, 
was measured by the present reporter in June 1844. The soil 
was frozen to a depth of 45 feet from the surface. (See ‘‘ Magnetic 
Survey,” p. 161.) 
6. Lat. 62° 39’ N., long. 115° 44’ W., at Fort Rae, on Great 
Slave |ake.—Capt. Dawson, R.A., observed the temperature 
of the soil monthly at his station of circumpolar observation, 
1882-83. The following table contains his results in degrees 
Fahr. :— 
Months 1 Foot 2 Feet 3 Feet 4 Feet 
1882 ms A 2 5 
September 40°6 37°9 30°1 34°5 
October... 32°5 32°7 32°5 32°53 
November 239 291 30°9 313 
December 15'8 24°6 28'8 30'S 
1883 
January O53) | esLOA9 PASE Te 28°5 
February Te Sen eee! 24°5 26°3 
March 9°5 20°8 22°7 24°8 
April TSO) eae e2he2 24°3 253 
May 24-0) eat) 3280 338 30°5 
June 43°5 36°5 32°4 315 
July 48:0 410 370 34°5 
August ... 47°3 41°9 38°5 36°5 
The mean temperature of the air at 5 feet 10 inches above the 
surface, in the same months, was as follows :— 
1882 1883 
September ... 44°40 | February ... ... ...— 10°41 
October... 32°59 | March ee = TR 
November ... 9°30 | April ... 19°30 
December ... ...- 15°20 | May 36°30 
| June 51°49 
1883 | July Orit 
January... ...— 26°80 | August 56'50 
We learn from this table that the soil is frozen at a depth of 
4 feet from November to June inclusive, and is at the lowest 
temperature at that depth in March. It further shows that, like 
the waters of the Scottish lakes, as proved by the observations 
of Mr. J. Y. Buchanan and Mr. J, F. Morrison in Loch Lomond 
and Loch Katrine last winter, the mean temperature of the soil 
reaches its minimum about the time of the vernal equinox. The 
rise of earth-temperature in February above that recorded in 
either January or March is remarkable. It does not appear, 
from the conversence of the lines when projected, that temper- 
atures below 32° F. extend lower than 11 or 12 feet. Capt. 
Dawson writes :—‘‘ There are two reasons why these earth- 
temperatures are above what is probably the average in that 
latitude. (1) The ground had a slope of 1/16 to the south-west ; 
and (2) it was fully exposed to the rays of the sun; now, in 
most places, the ground is either covered with thick moss or 
shaded by brushwood, and its surface-temperature on the hottest 
day is not likely to exceed 70° F., whereas earth exposed to the 
rays of the sun may easily reach a temperature of 120° F.” 
Fort Rae is situated on a long arm or inlet of Great Slave, 
having a depth of Io or 12 feet of water. 
7. Lat. 62°, long. 129° go’, Jakutsk, Siberia.—The great 
depth of permanently frozen soil in this part of the valley of the 
Lena has long been well known; but the following extract, 
translated from a recent paper by Dr. Alex. Woeikof, of St. 
Petersburg, entitled ‘Klima von Ost-Siberien,” contains in- 
formation on the influence of local conditions which will make 
it of value to observers, and we therefore reproduce it. 
[ Sept. 16, 1886 
“‘ The further north,” he remarks, ‘‘the longer is the duration — 
of cold in valleys in comparison with that on higher ground. 
The effect extends to a part of autumn and spring, and is obsery- 
able in the mean temperature of the year.” 
ane following observations of earth - temperatures are a 
proof :— 
At Depth Limit of 
20 ft. soft. 300ft. 38rft. Frozen Soil 
Jakutsk * 13°°6 17 ‘I 250 26°°6 Fahr. 620 feet. 
Mangan mine . 22 "1 25°'2 “00 269 ,, 
Schelou mine 22° 25°7 298 ,, 
Thus, on heights in the vicinity of Jakutsk (these are heights 
on the left bank of the Lena, near Jakutsk) the earth tempera- 
ture is from 8°*1 to 8° 6 F. higher than it is in the town and 
valley at the same depth, and it is even lower at 300 feet in the 
former than at 50 feet in the latter locality. The total depth of 
frozen soil is, according to Mittendorf (‘‘ Sibirische Reise,” 
Bd. i.) more than twice as great in the valley as it is on the 
heights : and observe that these lesser heights are in winter 
relatively colder than higher isolated mountains. Mittendorf 
also states that no frozen soil was found at 60 metres above the 
level of the river at the mouth of the Maja, in Aldan, but that 
it was found four miles and a quarter up the stream at three 
metres above the level of the river, and that about 28 miles 
further, in the mountains, there is a deep hollow from which 
aqueous vapour is constantly rising. 
Kuppfer asserts that in Bergrivier Nertschinsk, in the Trech 
Swijatitilei mine, frozen soil was found at a depth of 174 feet, 
but that in Wossdwischenst mine, which lies 230 feet higher, 
the frozen soil ceased at 50 feet. Even in Altai it is acknow- 
ledged that many valleys are colder than the neighbouring 
heights. 
Dr. Woeikof sums up a number of observations in the following 
sentences, which apply to the greater part of East Siberia, but 
more particularly to the north-east portion. 
(1) As the greater cold coincides with calms and light winds, 
the valleys and lower grounds are colder than the heights. ’ 
(2) The temperature of isolated mountains is relatively higher 
than that of lesser elevations. 
(3) The lowering of temperature in the valleys is so lasting 
and considerable that the mean of the year is also lowered, as 
is proved by the observations of earth-temperature. 
(4) The depth of the frozen soil is greater in valleys than on 
the neighbouring heights, probably also than it is on the higher 
mountains. 
(5) In the tundras of the far north (answering to the barren 
grounds and muskegs of the North-West Territory of Canada), 
the winter is warmer than in the valleys of the forest-zone. 
Probably because the stronger currents of the air do not permit 
the cold stratum to remain so long stagnant. 
8. Lat. 61° 51’, long. 125° 25’, Fort Simpson, on Mackenzie 
River.—The summer’s heat was found in October 1837 to have 
thawed the soil to a depth of 11 feet, below which was 6 feet of 
ground ice (Richardson), making the depth of descent of the 
frost 17 feet. The result is anomalous; at other posts in the 
same region the summer thaw is much more superficial. Thus, 
it will be observed above, that in the month of October, at Fort 
Rae, the soil was at a nearly uniform temperature, but slightly 
above the freezing-point, from the depth of 1 foot to 4 feet. 
Franklin found a summer thaw of only 22 inches at Great Bear 
Lake, and the writer was informed that it was only 14 inches at 
Fort Norman (lat. 64° 41). Fort Simpson is situated on an 
island of deep alluvial soil, bearing timber of large size, and 
possessing an exceptional climate. 
g. Lat. 57°, long. 92° 26’, York Factory, Hudson’s Bay.— 
Sir J. Richardson has stated that the soil was found frozen to a 
depth of 19 feet 10 inches in October 1835, the surface being 
thawed to a depth of 2 feet 4 inches. 
to. Lat. 55° 57’, long. 107° 24’, Lake a la Crosse.—It is 
stated that no frozen soil was found in sinking a pit to a depth 
of 25 feet in 1837, and that the earth was only frozen to a depth 
of 3 feet in the winter of 1841. Both records are anomalous, 
and call for verification. 
11. Lat. 53° 40’, long. 113° 35’, at Prince Albert, on the 
Saskatchawan.—Mr. W. E. Traill, who was in charge of this 
post in 1872, reports that a settler in the neighbourhood came 
to frozen ground at a depth of 17 feet, but did not learn whether 
they passed through the frozen strata, or, if such was the case, 
tM. Schergin’s shaft. 
