March 13, 1879] 



NATURE 



433 



Intellect in Brutes 

 In answer to the objections raised by W. P. Buchan and 

 Henry Muirhead to the case of rats gnawing water-pipes for 

 the express purpose of obtaining water, as described in my letter 

 to Nature, vol. xix. p. 365, I propose to give particulars of the 

 situation of the pipes so gnawed in two instances. No. I. 

 At Poplar. Pipe laid on second floor, between flooring-boards 

 above and ceiling below, between joists the usual distance apart ; 

 plenty of room all round pipes to^obtain access to any part of 

 the floor, also rat-holes in woodwork to facilitate communication. 

 As the pipe lay above the ceiling of the floor below, there was 

 no necessity to attack the pipe in order to get through that 

 ceiling — if that were desired. A hole could easily have been 

 made at any point on either side of the pipe. The upper floor 

 was a com loft, and it is inferred from the circumstances, that 

 the rats, feeding upon this very dry food, had tapped the water- 

 pipe to obtain a supply of water close at hand. No. II. On 

 Haverstock Hill. Cistern in scullery about six feet from the 

 floor, pipe (lead), comes thence do^vn wall, passes under floor 

 of scullery to kitchen to supply kitchen boiler. Pipe laid on 

 the earth, between joists, raised, of course, on bricks. Pipe 

 gnawed on upper side. Plenty of room all round for rats to 

 pass freely under all parts of the floor, as any practical builder 

 will readily understand. They could have tunnelled under this 

 j-inch pipe from either side through the soft earth. Of the two 

 holes in the pipe one will admit a small pin, the other is about 

 ^th of an inch in greatest diameter, and about an inch from the 

 first. These are transverse perforations, the ineffectual attempts 

 are in a longitudinal direction. It is of course quite possible, as in 

 Mr. Buchan's cases, that rats occasionally find gas-pipes in their 

 •way and are compelled to attack them, but I do not think any of 

 your readers will imagine that his question, "Now, are they cut 

 to get at the gas ? ' needs a moment's consideration. Possibly some 

 of your correspondents may be able to corroborate the following — 

 A ship's carpenter told me that, in the old days before the use 

 of iron tanks on board ship became general, the rats used to 

 attack the water casks, cutting the stave so thin that they could 

 suck the water through the wood, without actually making a hole 

 in it. If any one could substantiate this it would have an im- 

 portant bearing on the question under consideration. 



Arthur Nicols 



I AM glad my remarks have elicited others, for I want to have 

 my difficulty solved, which I wiU put thus : — Why is it that no 

 d(^ ever (to my knowledge, of course) observed a person ring a 

 bell, noticed that the bell brought the servant, and then went 

 through the process of reasoning — " Because such was the result 

 I will ring the bell too " ? This I call abstract reasoning. On 

 the other hand, why is it at all necessary to teach the dog to 

 ring the bell ? for it is not necessary to teach a boy. Boys do 

 acquire sooner or later abstract reasoning, but it is with them 

 jHractically a feeble power, as I have shown, and with rustics it 

 seems, sometimes, to be totally in abeyance, as the following 

 illustration will show. An entertainment was given to some 

 Inmdred labourers and their wives, and a Mr. Cross told them 

 to spend the afternoon in a field, but hoped none of them would 

 be his name. Not one understood him, or could go through the 

 simple process of reasoning — " We are not to be his name, 

 his name is Cross, therefore we are not to be cross." It is this 

 mental reflection which seems to me to be wanting in animals ; 

 thus, monkeys will warm themselves by a fire of burning sticks, 

 but do not seem capable of thinking — "Because sticks bum, 

 therefore, if I put more sticks on the fire I shall get more 

 ■warmth." I should be extremely glad to hear of any cases of 

 sach purely abstract mental reflection in animals, for at present, 

 there seems to me to be a hiatus here. 



George Hexslow 



On the Freezing of Lakes 



We wish to draw your attention to a statement contained in 

 an article under the above heading which appeared in Nature 

 last week, p. 412. 



The author, Mr. J. Y. Buchanan, says : — 



" Most of the observations were made with one of Negretti 

 and Zambra's ' half turn ' deep-sea thermometers, which proved 

 a useful instrument for this species of inquiry. It was necessary, 

 however, to fit it with a suitable inverting contrivance, as the 

 apparatus supplied for this purpose by the makers is quite 

 useless." 



I Fortunately this thermometer and apparatus has now been in 



' use for some time, and i's performance fully tested by persons 



whose opinion is of the highest value. We can only say that 



had Mr. Buchanan used the apparatus according to our printed 



I direction, viz., lowered the instrument to the required depth, let 



I it remain a few seconds, and then pulled it up as fast as practi- 



I cable and without stopping, he would not have failed to have 



1 obtained correct results. We cannot possibly imagine how he 



could have failed ; had we not ourselves tried the inverting 



apparatus in every possible way, and had we not received the 



I highest testimony as to its efficiency, we would have remained 



I silent, but as it is, and knowing we have invented as good an 



instrument as has ever been contrived for the purpose, we cannot 



allow the statement to pass tmchallenged that we have supplied 



a useless apparatus. If Mr. Buchanan could not obtain satis- 



i factory results with our apparatus it must only have been 



because he did not use it as wo directed. 



Hy. Negretti and Zambra 



THE MIGRATION OF BIRDS 



MORE than four years ago an article, headed as above, 

 appeared in this journal (vol. x. p. 415) giving rise 

 i to some comments of more or less importance {torn, at., 

 \ pp. 459, 520, and xi. p. 5). Since that time two very re- 

 ' markable treatises on the subject have come forth, the 

 • one by Dr. Palmdn, on the routes taken by birds 

 ; in their migrations, and the other by Dr. August 

 i Weissmann, dealing generally with the whole ques- 

 j tion.' The first, originally published in Swedish,^ was 

 I translated into German soon after, and in due time 

 ! was reviewed in these columns (voL xv. p. 465). An 

 ' excellent English version of the second has recently 

 j appeared in the "Contemporary Re\'iew" (February, 

 ' 1879, p. 531), and therefore my readers may be presumed 

 ! to be acquainted with the views of both authors. It can- 

 j not be denied that each of them has to some extent en- 

 larged the boundaries of our knowledge of the subject, 

 ! and still more widely those of our speculations upon it. 

 As regards Dr. Palm^n's work, the opinion held by his 

 reviewer in these columns as to the assignment of routes 

 to the migratory birds of North- Western Europe being 

 " pvu"ely conjectural " is one that I wholly accept. I 

 should even be inclined to go further, and say that it 

 might be caUed rash, as it is evident that no such ob- 

 servations as would justify its adoption exist. Still I 

 concur with the reviewer in that I would not at present 

 term it entirely erroneous, though I venture to express 

 my entire disbelief in the route " X." This is supposed 

 by Dr. Palmen to start from Greenland and Iceland, and 

 to pass by the Faeroes to the Hebrides, when, after 

 coalescing for a short distance with one or more lines from 

 the north-east, it either loses itself on the West Coast of 

 Ireland, or, running do\\-n St. George's Channel, skirts 

 Scilly and crosses to the shores of the Bay of Biscay. 

 Space forbids my entering into details which would show, 

 I think, that this route is altogether imaginar)'. I wiU 

 only say that what we know of the movements of two very 

 characteristic summer visitants to Iceland, Motacilla alba 

 and Limosa agocephala, points to that conclusion, and I 

 would leave it for Irish ornithological observers to prove 

 whether Dr. Palmdn is right or not. 



Dr. Weissmann, happily for him, has no such com- 

 punction. He fully accepts Dr. Palmdn's conjectures as 

 absolute truths. Suppose, however, we assume them to 

 be estabhshed — and there seems no reason why fiuiher 

 observation should not establish most of them — they 

 would show in Dr. Weissmann's opinion that the mi- 

 grating birds of to-day in crossing the sea follow what 

 once were "land-bridges" {Landbnicken), that is, isth- 

 muses of dry land separating seas or oceans under which 

 they are now submerged. The existence of such former 

 terrestrial communications between continent and con- 



' Sammlung gemeinstandlicher wlssenschaftlich^ Vortrage. XIII. Serie 

 Heft 291. " Ueber dasWandem der Vogel." Berfin, 187S. 

 ' Om Foglames flyttniogsvagar. HelsiDgfors, X874. 



