BOTANICAL INFORMATION. 153 
be destroyed by a single dash of the hand, yet all this is of no avail ; 
their place is instantly reoccupied by fresh recruits. At last a person 
becomes so fatigued with unsuccessful attempts of freeing himself 
from his tormentors, that he is obliged to give up killing them in de- 
spair, and to submit patiently to their irritating operations. 
On the 19th of July, the three vessels, Herald, Plover, and Nancy 
Dawson, left for Point Barrow. It was beautiful summer weather. 
The sky was blue and serene, the sea perfectly free from ice, and the 
sun shining without intermission during the twenty-four hours. I 
had often longed to witness the latter phenomenon, in order to observe 
its effect upon the so-called s/eep of plants. It is generally supposed 
that daylight is the great agent which causes leaves to expand. By 
observation I arrived at a somewhat different conclusion. When we 
left for the north, I planted some seeds of a new species of Phaseolus 
found on the Andes of Veraguas. The place was so situated that the 
sun could scarcely ever shine upon them, though they had plenty of light 
and air. While we remained within the boundaries of the tropics 
their leaves shut up at five o'clock p.M., sunset being at six p.m. The 
farther we proceeded towards the north, the longer they remained ex- 
panded; and when the sun disappeared at ten P.M., they fell asleep at 
eight p.m. This, however, was their latest hour ; they never remained 
expanded after that time, even when, in the higher latitudes, the sun 
was, at midnight, high above the horizon. The mere daylight made 
no alteration ; yet the leaflets could at any time be made to expand by 
directing the rays of the sun upon them. 
We passed Cape Lisburne, a high promontory, Icy Cape, a low 
spit, and anchored, on the 24th of July, off Wainwright’s Inlet, in lat. 
70° 36’ north. From that place four boats of the expedition and the 
Nancy Dawson started for the Mackenzie river, while the Herald and 
Plover, resuming their voyage without delay, obtained, on the 26th of 
July, the first sight of the packed ice. The ice-line extended from 
S.E. to N.W. It was traced by both vessels until, in the morning of 
the 28th of July, after having attained lat. 72° 48’ north, three de- 
grees higher than had from this side ever before been reached, all 
further progress was impeded by huge masses of ice, the habitation of 
numerous Walruses. Being thus prevented from penetrating farther - 
northward, the ships returned to Wainwright’s Inlet, which had been 
suggested as a wintering-place for the Plover; and while the hy- 
VOL. II. x 
