3 2 4 



NATURE 



[Feb. 5, 1880 



by-and-by to become a universal possession in more or less 

 degree. 



It may require some peculiar state of mental calm or abstrac- 

 tion for tbis reading of tbe thoughts of another (apart from 

 external expressions appreciated by the other senses) to become 

 practicable, just as, in order to perceive distinctly the over-tones 

 of a musical sound, it may be necessary to quench the funda- 

 mental tone. 



As to the modification in the human body, supposing the 

 sense in question to become general, this might be of a very 

 minute character, constituting, not in the ordinary view, yet in a 

 quite correct one, a distinct organ. 



With regard to the influence of distance on the supposed sei se, 

 little, of course, can be said ; but it is perhaps noteworthy that 

 corresponding to the gradation referred to at the outset there is 

 a general gr dation in the distance at which the sense-exciting 

 cause is capable of operating ; from the direct contact of touch, 

 to the action of light at the distance of a remote fixed star. 



M. 



The Circumference of the Circle 

 To some readers of Nature the following 'construction will 

 crimps be of interest : — 

 Take A O B, D C two diameters of a circle at right angle., I 

 one another. 



Make tbe length of the tangent D S equal to three diameters 

 of the circle A D B C, then make the angle A P = 60°, and 



J) 



draw PR at a right angle to D C. Connecting the points S and 

 R you will find the length R S very nearly equal to the circum- 

 ference of the circle. 



This will be clear from the following proof : — 



From the triangle D R S we have — 



RS= ^DlP + DS-. 

 But taking the diameter D C = I the length D S is =3, 

 whereas D R = OD + OP cos 30 = J + J cos 30 = 0-9330127. 

 Therefore — 



D R- = o-933oi27 2 = 0-8705127 and 

 D S- = 3- = 9'oooooco 



BR 2 + DS- = 9-8705127 

 RS= >JjDR* + D S- - 3-141738, whereas the exact 

 value of tt is 3-141592, 



giving a difference of 0-000146, or 0-0046 per cent. 



This approximation is, of course, more than sutficient for 

 practical purposes. Although this method has been found by 

 me quite independently, yet I shall not be surprised to hear of 

 its having been proposed before by others, for it is almost too 

 simple not to have occurred to somebody else as well as to me. 

 Prague, Spalena ulice, 2 nove, January 11 L. Hajnis 



Sun-Spots, &c. 



I read with interest the letter of Mr. Bedford's in Nature, 

 vol. xxi. p. 276, on "Sun-Spots." Perhaps the following may 

 interest Mr. Bedford, and as I have not seen this noticed before 

 by students of the solar orb, it may interest others besides Mr. 

 Bedford. 



Prof. Sayce, in his Lectures, says: "The Accadians had 

 anticipated our almanack- makers in discovering a connection 

 between the weather and the changes of the moon; indeed all 

 kinds of astronomical phenomena were supposed to have an 

 influence upon the clouds; and in anticipation, as it were, of 

 Dr. Hunter, the same weather was expected to recur after a 

 cycle of twelve solar years." . . . Even the appearance of the 

 sun u as not allowed to go unnoticed, and in one place we are 

 told that on the 1st of Nisan it was "bright yellow," and in 



another that it was " spotted." Who, says the professor, " would 

 have thought of looking for a notice of sun-spots in the clay tablets 

 of ancient Babylonia?" Lectures, pp. 53-54. See also the 

 " Astronomy and Astrology of the Babylonians," by the same, 

 in the Transactions of the Society of Biblical Archaeology, vol. 

 iii. pp. 145, 339. Edward Parfitt 



Devon and Exeter Institution, Exeter, January 27 



Intellect in Brutes 



It might prove interesting to some of your readers to put the 

 following incidents on record relative to intellect in brutes : — 

 Some time ago I kept in town a bitch and three of its puppies ; 

 the former had a strong pair of lungs and a weakness for letting 

 the pas-ers-by know it ; when the latter became of age they 

 exhibited all the hereditary peculiarities of the mother, and when 

 the four animals joined in chorus, which was their favourite 

 amusement at night, the result was anything but agreeable. 

 Some of my friends hinted to me that if that state of things 

 continued I should probably be indicted for causing a nuisance, 

 and 1 therefore determined to explain to my four animals that 

 they really mustn't bark. One night I remained late in town, 

 and having provided myself with a stick, I waited till I heard 

 one of them bark, and I immediately afterwards went out and 

 chastised him, or rather the one I thought had made the noise. 

 I was, however, soon met by a difficulty ; although I could 

 recognise the bark of the old one, I could not discriminate well 

 between those of the puppies ; and whil-t the old 

 one was silenced after a few chastisements, the 

 puppies were not ; probably in mistake I had 

 thrashed the wrong puppy. I therefore hit upon 

 the plan of making the whole four responsible for 

 each other, and as so)n as I heard any one of 

 them bark I applied my stick freely to the whole 

 four, the one after the other. When this had been 

 done two or three times I heard one of the puppies 

 bark, and the next moment it gave a pitiful squeal ; 

 the mother had it by the neck. I went out and 

 S patted her, thus explaining that she had done well. 

 She wagged her tail, as much as to say she under- 

 stood me perfectly, and the dogs never barked again except upon 

 the most provoking occasions. 



Some other instances which I observed lately might be men- 

 tioned as tending to show that animals of a much lower class 

 exhibit reasoning faculties. I had occasion lately to keep some 

 leeches and water-beetles ; they were put into round open glass 

 vessels, about six inches high and about two-thirds full of water. 

 A medical leech which was put into one of these vessels got out, 

 and within an hour afterwards it was found on the table and 

 replaced in the water. Now although the vessel was left un- 

 covered as before, this leech never again tried to get out. A 

 horse-leech and two water-beetles, treated in the same way did 

 the same thing once, and once only ; each preferred the water 

 to the dry table, and on being replaced they never tried to get 

 out again ; ergo, they had been taught by experience. Is this 

 not a high order of intelligence? How many examples have we 

 of the genus homo where so much intelligence is not exhibited? 

 Manchester, January 17 W. Thomson 



Seeing a letter in Nature, vol. xxi. p. 276, with the 

 beading of a " clever spider," puts me in mind of a circumstance 

 that came under my own observation near Tremadoc, in North 

 Wales, many years ago. I sat down on a bank about four 

 o'clock in the afternoon after a long day, when I presently saw 

 1 was close to one of the common garden spiders of rather large 

 size, with its pretty spreading net-like web about a yard from 

 the ground ; so, for want of something to do, I alarmed the spider 

 to discover where his den was, when off he trotted about the 

 distance of a foot to a couple of leaves nicely tied together, where 

 lie stayed perhaps ten minutes ; I then saw a beetle of rather 

 large size walking at my feet— one of those slow moving dull 

 black ones — I am not coleopterist enough to know its name ; 

 I picked it up and put it in the web at a place I thought suffi- 

 ciently strong to hold it, when out rushed the 

 his boldest manner. But when he saw who his visitor was, what 

 an alteration in his manner! lie drew back, and rapidly sepa- 

 rated the cords, when down dropped the beetle on a single line, 

 rather quickly, to within about 4 inches of the grou d 

 he was suspended on a line about 2I5 feet long. The sp 

 trotted back to his den. The beetle was now struggling in its -low, 



