THE SPOCTTING AND MOVEMENTS OF WHALES. 629 



3. Noise of the spout. — The noise produced by the spout is also very 

 variable in intensity, in accordance with the size of the animal. 

 Scarcely perceptible in DeJpMnus delphis L. (the common dolphin) 

 and its allies, it becomes very loud in the small tinbacks, louder still 

 in the right whales and the humpbacks, and of a force truly extraordi- 

 nary in a Balxnoptera mibsculus L. (sulphurbottom) of great size. 

 This sound has been compared with good reason to the noise made 

 b}' steam escaping from a pipe under pressure; from a brass pipe, 

 I may add, because very often the spouts of the iinl)acks possess 

 remarkable sonorousness. It is not a true emission of voice, because 

 whales have no vocal cords, but a simple vibration caused by the expul- 

 sion of air under pressure. The effect is often produced even in man 

 when the nose is for any reason obstructed by foreign substances. 

 It is not rare, indeed, to observe whistling sounds which, with a due 

 allowance for difference in proportions, are of the same nature as the 

 more or less musical sounds produced by whales. It is in this waj^ 

 that I explain the bellowings so often described as occurring among 

 cetaceans. I ought, moreover, to mention that among certain por- 

 poises it may be that there are special dispositions of parts which 

 produce noises in a constant manner. 



Jf.. Form and appearance of the spout. — ^The form and appearance of 

 the spout depend much on the force with which the air stored in the 

 lungs is expelled; they depend also on the rapidity of motion of the 

 animals and the state of the atmosphere. Among small whales the 

 spout is invisible, or very little visible, and the whale must exceed at 

 least 10 meters before its spout will be visible. 



The appearance of the spout is that of a mass of white and pearly 

 vapor. When it is calm and cold and when the whale is quiet or 

 moves gently, the spout rises vertically in the air in a column more or 

 less slender according to the species. The right whales emit a very 

 larg-e spout and the tin backs a small one. As the upper part of the 

 colunm becomes enlarged the spout takes the form of a very much 

 elongated cone, but before the end of the expiration the summit of 

 this elongated cone spreads out, its outlines become vague, and the 

 terminal part is transformed into a sort of cloud. At the end of the 

 expiration the spout detaches itself from the blowhole, rises gently in 

 the air, and the lower part disappears; it seems to gather itself together 

 into the upper cloud, and finally the upper cloud also dissolves. This 

 is noticed especially in the case of the first spout after sounding, 

 which is always more forceful. 



On the other hand, in expirations during the interv^ening appear- 

 ances at the surface the column formed by the spout is less high, the 

 cone which it forms is much less elongated, and its duration in the air 

 is much less. When the wind blows or when the animal is in rapid 



