3S ■ MAMMALIA. 



of copper or brass : it is a very deep and ybtj loud sound, sus- 

 tained during eight or ten seconds. 



According to the same observer, the spout is not formed of any- 

 liquid water : it is composed at one and the same time of hot 

 air issuing from the chest, of a certain quantity of vapour of 

 water, mixed with this air, and of greasy particles. So, when the 

 temperature is rather high, the sea calm, and, above all, when 

 the sun is near the zenith, this blowing, or spouting, is in- 

 visible. When the vapour from this blow-spout is disseminated 

 into the air, it dissolves — all disappears : there falls nothing but a 

 few little drops of greasy matter. These drops, diffused over the 

 surface of the water, and joined to the exhalations of the skin, 

 leave on the surface of the sea long trails of oily sj)ots, which show 

 the way by which the Whale has passed. At all events, there is 

 always a certain quantity of water, which has penetrated into the 

 aerial canal terminated by the blow-hole, and this water (about 

 one or two litres) is mixed in a state of minute subdivision or 

 particles, with the respired air, and disseminates itself in the 

 atmosphere, like the pulmonary moisture. 



In speaking above of the habits of the Whale, we only pointed 

 out, with Dr. Thiercelin, that it was continually " moving on." 

 But at what rate does it proceed when it is travelling along ? 

 Lacepede affirms that it travels over 660 metres a minute : that 

 it goes quicker than the trade winds. If it went twice as fast as 

 it actually does, that it would beat the most impetuous winds ; if 

 thirty times, it woidd traverse space as quickly as sound. 



Starting from this hj'pothesis, Lacepede makes another curious 

 calculation. SujjjDosing that twelve hours of repose a day is 

 sufficient for the Whale, it wotdd take only forty-seven days in 

 going roimd the world, following the equator, and twenty-four 

 days in going from one pole to the other along a meridian line. 

 These calculations of the illustrious French naturalist are based 

 upon a rather exaggerated estimate of the animal's speed. On the 

 other hand, certain authors, keeping no doubt within the truth, 

 have affirmed that the Whale travels over only three marine 

 leagues an hour. This is the opinion of the too ingenious Boitard.* 



* Le Jardin des Plantes de Paris. The fact is, that the higher rate of speed 

 denotes the pace of the liorquals, and the lower rate of speed that of the Eight 

 Whales. The former are conspicuoush* fast-built, the latter slow and bara'e-like 

 —Ed. ^ 



