538 
From all the above, it is evident that naviga- 
tion in coast-waters must be slow and gradual, 
although it has always been attended with the 
greatest advantages. Inshore navigation is 
not without its hinderances, however, and es- 
pecially is this the case where the water near 
the coast is very shallow; and this could be 
remedied only by a light-draught vessel, which 
has the disadvantage that such a vessel cannot 
conform to the build already indicated. This 
is especially the case on the polar shores of 
the mainland of America, Asia, and most of 
Europe, while in the channels and waters north 
of them the land rises higher, the navigable 
waters approach more closely to the shore, and 
progress forward becomes more easily assured. 
Also in coast-water cruising, a vessel forced 
upon the shore by the incoming pack, backed 
by a heavy gale, is in a more precarious state 
than one simply grounded or lifted upon an 
ice-field. 
A ship once. fairly beset, and strongly held 
during a gale, is completely beyond control ; 
and no real good can be accomplished by the 
severe tasks of warping and continual shifting 
of ice-anchors, which only exhaust the crew, 
and render them more or less unable to take a 
thorough advantage of a favorable situation, 
should one occur. Parry, however, under 
these circumstances, did not hesitate to employ 
his crews to their utmost at the hawsers and 
sails, plainly acknowledging that ‘‘ the exer- 
tions made by heaving at hawsers, or other- 
wise, are of little more service than in the 
occupation they furnished to the men’s minds 
under such circumstances of difficulty ; for, 
when the ice is fairly acting against the ship, 
ten times the strength and ingenuity could in 
reality avail nothing.’’ But the greater ma- 
jority of ice-navigators are now decidedly of 
the opinion that it is best to yield to fate, and 
reserve the men’s strength for palpable efforts. 
Still, in these besetments the mind of the com- 
mander must be ever active; for new events 
follow each other so rapidly, that a favorable 
chance for rescue is passed, before it can be 
fairly weighed in all its aspects. 
FREDERICK SCHWATKA. 
NOTES ON HIBERNATING MAMMALS. 
A veERY prevalent impression exists, that 
hibernation among mammals is so fixed a 
habit that it may be defined in a few words, 
that it occurs with all the regularity of sleep, 
and is as necessary to the creature’s welfare as 
food or drink. So far as these hard and fast 
SCIENCE. 
lines are drawn, so far is our understanding of 
the subject warped and imperfect. 
In the ninth edition of the Encyclopaedia 
Britannica, hibernation is defined as that ‘* pe- 
culiar state of torpor in which many animals 
which inhabit cold or temperate climates pass 
the winter.’’ Here we have the characteristic 
feature of the habit clearly expressed; but, 
when we come to consider the minor details, 
we do not find that any two animals, however 
closely allied, hibernate in precisely the same 
manner, nor do individuals of the same species 
always hibernate alike. Further, we do not 
find that it is so common an occurrence as 
usually supposed ; 
hibernate merely because winter has ‘ set in,’ 
regardless of the temperature then prevailing. 
My own studies of the animal life in this neigh- 
borhood (central New Jersey) lead me to con- 
clude, rather, that it is a happy faculty, which 
certain animals possess, but do not willingly 
exercise. Ifthe prevailing temperature forces 
them, in self-defence, to hibernate, they can ; 
but so long as they are able to withstand a 
low temperature, and food is accessible, they 
resist. Other causes than cold may induce an 
animal to hibernate ; as when deprived of the 
supply of food gathered during the preceding 
autumn. In such a case, squirrels will pass 
the winter in a state of torpor, however mild 
the weather; while, with an abundant food- 
supply, they will simply sleep through the 
colder days, and awake to feast whenever the 
sun shines brightly. 
Of the thirty or more mammals found here, 
thirteen species are supposed to be hibernating 
animals. These are four species of bats, two 
of moles, three squirrels, one ground squirrel, 
one marmot, one jumping-mouse, and one Hes- 
peromys. Of these, probably the bats are the 
most sensitive to cold, and avoid exposure to 
it with the greatest care; and yet I find that 
the little red bat (Atalapha novaeboracensis) 
is very late in retiring for the season, and re- 
appears with great regularity early in Febru- 
ary. 
considerable food is to be had, — that flying in- 
sects are abundant. While this bat’s ordinary 
habits do not differ noticeably from those of the 
other species, it is apparently less sensitive to 
low temperature, and needs but the least en- 
couragement to arouse from its hibernating 
sleep. It is also less crepuscular in habit 
than the others; but I do not know that this 
fact has any bearing upon the irregularity of 
its hibernation. 
Bats disappear in November or December, 
immediately after the formation of ice, but do 
and no animal appears to 
Their actions at this time indicate that | 
~~, 
