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THE POPULAR SCIENCE MONTHLY. 



animals whereby they are infallibly guided 

 on their return homeward from distant 

 places. Mr. Wallace thinks that this fac- 

 ulty is, in dogs at least, simply a very acute 

 sense of smell. According to him, the dog 

 "takes notes by the way" of the various 

 odors he passes through, and finds his way 

 back by taking the links of this chain in 

 reversed order. But this explanation is 

 open to very serious difficulties, and Mr. 

 Darwin's simpler theory will appear far pref- 

 erable. 



Indeed, Mr. "Wallace's theory seems 

 hardly broad enough to account for more 

 than a very inconsiderable fraction of the 

 phenomena which it is proposed to explain. 

 For dogs, cats, horses, and the like, it may 

 be good enough, until a better theory is 

 found. But what possible application could 

 it have to such a case as the following, 

 which is given by Mr. Edward W. Cox, on 

 the high authority of Mr. Robert Fox, of 

 Falmouth ? " The fishermen of Falmouth," 

 writes Mr. Cox, " catch their crabs off the 

 Lizard Rocks, and they are brought into the 

 harbor at Falmouth alive, and impounded 

 in a box for sale, the shells being branded 

 with marks by which every man knows his 

 own fish. The place where the box is sunk 

 is four miles from the entrance to the har- 

 bor, and that is above seven miles from the 

 place where they are caught. One of these 

 boxes was broken ; the branded crabs es- 

 caped, and two or three days afterward they 

 were caught again by the fishermen at the 

 Lizard Rocks. They had been carried to 

 Falmouth in a boat. To regain their home 

 they had first to find their way to the mouth 

 of the harbor, and, when there, how did they 

 know whether to steer to the right or to the 

 left, and to travel seven miles to their native 

 rocks ? " 



It is unphilosophical to set up many dif- 

 ferent hypotheses, where one would answer. 

 For this reason we are inclined to accept 

 Mr Darwin's explanation of the phenome- 

 non in question, rather than Mr. Wal- 

 lace's. Mr. Darwin, it will be seen, aims at 

 bringing all the phenomena under one gen- 

 eral law, that of a Faculty of Direction, as 

 it may be called. In confirmation of this 

 hypothesis, the veteran naturalist quotes 

 from Von Wrangell's account of his ex- 

 pedition to North Siberia, as to the " won- 



derful manner in which the natives kept a 

 true course toward a particular spot, while 

 passing for a considerable distance through 

 hummocky ice, with incessant changes of 

 direction, and with no guide in the heavens, 

 or on the frozen sea." Even with the aid 

 of a compass, an experienced surveyor in 

 Von Wrangell's party failed to do what 

 these savages easily effected. Mr. Darwin 

 says the Siberians keep a sort of " dead 

 reckoning " of their course, correcting their 

 deviations partly by eyesight, partly also, 

 perhaps, by a sense of muscular movement, 

 as some men can, even with bandaged eyes, 

 proceed for a short distance in a straight 

 line, turn at right angles, or even back 

 again. Some persons are " turned around," 

 as we say, far more easily than others. 

 Such persons would very easily lose their 

 way, were they to attempt traversing an ex- 

 tensive forest, for instance. Mr. Darwin is 

 inclined to think that some part of the brain 

 is " specialized for the function of direction." 

 If that is the case, it is very natural to sup- 

 pose that this specialization may be more 

 marked in beasts and savages than in civ- 

 ilized man, as the former have more con- 

 stant need to exercise the faculty of direc- 

 tion than the latter. Mr. Darwin closes his 

 communication on this subject by citing a 

 case from Audubon, where the faculty of 

 direction was egregiously at fault. The 

 great ornithologist kept a pinioned wild- 

 goose in confinement, and, when the time for 

 migrating came, the bird escaped. Instead 

 of proceeding due southward, as it should 

 have done, the poor creature began its long 

 journey on foot, travelling due northward, 

 exactly the wrong direction. 



Habits of the Porpoise. The behavior 

 of the porpoise in the Brighton (England) 

 Aquarium has been studied with warm 

 interest, by Mr. Henry Lee, F. L. S., who 

 communicates to Land and Water an in- 

 teresting account of his observations. Mr. 

 Lee had previously enjoyed frequent oppor- 

 tunities of watching the porpoise at sea, 

 whether from the bow of a steamer, or over 

 the gunwale of a boat, but an uninterrupted, 

 broadside view of all its movements was, for 

 him, " a new, delightful, heart-stirring sight, 

 and one often longed for." He observed 

 that the tail, with its flat blade spread out 



