3S 
MAMMALIA. 
of copper or brass : it is a very deep and very loud sound, sus- 
tained during eight or ten seconds. 
According to the same observer, tbe spout is not formed of any 
liquid water : it is composed at one and tbe same time of bot 
air issuing from tbe cbest, of a certain quantity of vapour of 
water, mixed with this air, and of greasy particles. So, when tbe 
temperature is rather high, tbe sea calm, and, above all, when 
tbe sun is near tbe zenith, this blowing, or spouting, is in- 
visible. When tbe vapour from this blow-spout is disseminated 
into tbe air, it dissolves — all disappears : there falls nothing but a 
few little drops of greasy matter. These drops, diffused over tbe 
surface of tbe water, and joined to tbe exhalations of tbe skin, 
leave on tbe surface of tbe sea long trails of oily spots, which show 
tbe way by which tbe Whale has passed. At all events, there is 
always a certain quantity of water, which has penetrated into tbe 
aerial canal terminated by tbe blow-bole, and this water (about 
one or two litres) is mixed in a state of minute subdivision or 
particles, with tbe respired air, and disseminates itself in tbe 
atmosphere, like tbe pulmonary moisture. 
In speaking above of tbe habits of tbe Whale, we only pointed 
out, with Dr. Tbiercelin, that it was continually “ moving on.” 
But at what rate does it proceed when it is travelling along P 
Lacepede affirms that it travels over 660 metres a minute : that 
it goes quicker than tbe trade winds. If it went twice as fast as 
it actually does, that it would beat tbe most impetuous winds ; if 
thirty times, it would traverse space as quickly as sound. 
Starting from Ibis hypothesis, Lacepede makes another curious 
calculation. Supposing that twelve hours of repose a day is 
sufficient for tbe Whale, it would take only forty- seven days in 
going round tbe world, following tbe equator, and twenty-four 
days in going from one pole to tbe other along a meridian line. 
These calculations of tbe illustrious French naturalist are based 
upon a rather exaggerated estimate of tbe animal’s speed. On tbe 
other band, certain authors, keeping no doubt within tbe truth, 
have affirmed that tbe Whale travels ' over only three marine 
leagues an hour. This is tbe opinion of tbe too ingenious Boitard.* 
* Le Jardin des Plantes de Paris. The fact is, that the higher rate of speed 
denotes the pace of the Eorquals, and the lower rate of speed that of the Eight 
Whales. The former are conspicuously fast-huilt, the latter slow and barge-like. 
■ — Ed. 
