70 SEA FABLES EXPLAINED. 



before it is uncovered to take in a fresh supply of air, the 

 water above its orifice is thrown up as by a sHght subaque- 

 ous explosion, or as by the momentary opening under 

 water of the safety-valve of a steam boiler. Some idea of 

 the force and volume of the blast of air from the lungs of 

 even the common porpoise may be formed when I mention 

 that one of the porpoises at the Brighton Aquarium, 

 happening to open its spiracle just beneath an illuminating 

 gas jet fixed over its tank, blew out the light. 



In the sperm whale the nostrils are placed near the 

 extremity of the nose, and therefore this whale has to raise 

 its snout above the surface when it requires to breathe ; 

 but instead of this being necessary, as in the case of the 

 porpoise twice or thrice in a minute, the sperm whale only 

 rises to " blow " at intervals of from an hour to an hour and 

 twenty minutes. Mr. Beale says* that in a large bull sperm 

 whale the time consumed in making one expiration and one 

 inspiration is ten seconds, during six of which the nostril is 

 beneath the surface of the water — the expiration occupying 

 three seconds, and the inspiration one second. At each 

 breathing time this whale makes from sixty to seventy 

 expirations, and remains, therefore, at the surface ten or 

 eleven minutes, and then, raising its tail, it descends 

 perpendicularly, head first. In different individuals the 

 time required for performing these several acts varies ; but 

 in each they are minutely regular, and this well-known 

 regularity is of considerable use to the fishers, for when a 

 whaler has once noticed the periods of any particular whale 

 which is not alarmed, he knows to a minute when to expect 

 it to come to the surface, and how long it will remain there. 

 The " spout " of the sperm whale differs much from that of 

 other whales. Unlike, for instance, the straight perpen- 

 * ' Natural History of the Sperm Whale.' Van Voorst, 1839. 



