Feb. 14, 1884J 



NATURE 



;57 



the act of swallowing', which temporarily distends the tube. He 

 can test its perviousne^s by holding his noie with his finjers and 

 forcing air into the nasal cavity. Physicians are in the habit of 

 placing an ordinary stethoscope over the ear, causing the patient 

 to gj through the act of deglutition, and listening for the "click" 

 of escaping air. Mr. Boys will see, as a physicist, that, if the 

 access of air on either side of the tympanum were free, increase 

 or decrease of atmospheric pressure would make no difference. 

 14, Dean's Yard, February 10 W. H. Stone 



With regard to the letter of Mr. C. V. Boys in Nature of 

 February 7 (p. 333), I should like to make a remark or two on 

 the matter, in which I have had practical experience. I am in 

 the habit of running between Rugby and London daily, and pass 

 through six diflerent tunnels on the route. The I.eighton tunnel 

 is divided into three parts, the down fast line being single, and 

 the space between the rails and the wallsof the tunnel very small. 

 On entering this, if in the first three coaches next to the ergine, 

 a sudden expansion of the tympanum is felt. I have been led to 

 account for this phenomenon as follows ; The engine acting as 

 a piston forces the air before it through the tunnel, and so causes 

 a partial vacuum, which extends to the first three or four coaches. 

 After that the air has had time to rush in and fill the empty 

 space, and this explanation is rendered almost certain by the fact 

 that at the end of the train of twelve or fourteen coaches no 

 aural effects are observable, thus demonstrating that the sudden 

 propulsion of the air through the tunnel is compensated for before 

 the middle of the train has entered. In Kilsby tunnel nothing 

 has been noticed by myself. I account for the pressure altera- 

 tion in the above manner, the engine and the tunnel-mouth 

 closely fitting, and so are fairly comparable to a piston within a 

 cylinder. The effects decrease from the engine to the end of the 

 train, and are practically unobservable in the last few coaches. 



Rugby, February 9 George Rayleigh Vicars 



Diffusion of Scientific Memoirs 

 Allow me a few final words on this curious case. I spoke 

 of the Trans, C. P. S., 1849-54, in which Stokes' papers were 

 "buried," as "al.nost inaccessible." This expression was chal- 

 lenged by the ex- Secretary of the Society, and I replied that the 

 question could be decided by statistics alone. I itidicated what 

 statistics were required, and waited some Aveeks for them. The 

 present Secretary then gave me the less essential part of the 

 desired information, and I proceeded to make the best I could 

 of it. Now I am told that I misunderstood his object, and that 

 he practically admits what his predecessor challenged. 



I also stated that my copy of the Proc. was very imperfect, 

 and that I had not received any Trans. I was then told that 

 "publications" were given only on application. If si, I 

 replied, I should have had all, or none. To this there is no 

 answer. P. G. Tait 



Coll. Ediii., February g 



Wind Sand Ripples 



Some time ago, whilst reading an account in Nature of very 

 ingenious and interesting experiments by Prof. G. H. Darwin 

 on sand ripples, my memory was recalled to some very beautiful 

 sand ripples caused by the action of wind, seen by another 

 person and myself on the west coast of Ireland, near Bundoran. 

 The locality was a sand ridge twenty or thirty feet above high- 

 water mark, and beyond the influence of either sea or river 

 action ; the ripples extended over a space of twenty yards or 

 more. At the time there was a fresh breeze, with frequent 

 squalls, blowing across this ridge. This ripples moved before the 

 wind at the rate of about a foot in three or four minutes, but 

 faster during the squalls, retaining all the time (I watched them 

 an hour or more) perfect uniformity of shape and size. The 

 distances were roughly measured by sticking up in the sand bits 

 of wood at, as nearly as could be guessed, one foot apart, in a 

 line with the direction of the wind. The ripples were about 

 three inches from summit to .summit, and the depth of trough 

 three quarters of an inch. 



The time was carefully noted wih a watch. The forward 

 movement of the ripples was evidently caused by the sand being 

 drifted from their weather sides, and deposited on their lee, and 

 thus there was a progressive movement to leeward, more or less 

 rapid according to the increase or diminution of the wind force. 

 4, Addison Gardens, February 9 John Rae 



Animal Intelligence 



The following anecdote, received the other day from Russia, 

 may possibly interest your readers : — "The following was nar- 

 rated to me by Mohl's brother, on whose estate it took place. 

 The carcass of a cow was laid out in the woods to attract the 

 wolves, and a spring-trap w-as set. Next morning the forester 

 found there the track of a bear instead of a wolf on the snow ; 

 the trap was thrown to some distance. Evidently the bear had 

 put his paw in the trap and had managed to jerk it off. The 

 next night the forester hid himself within shot of the carcass to 

 w atch for the bear. The bear came, but first pulled do» n a 

 stack of firewood cut into seven-foot lengths, selected a piece to 

 his mind, and, taking it up in his arms, walked on his hind leg; 

 to the carciss. He then beat about in the snow all round the 

 carcass with the log of wood before he began his meal. The 

 forester put a ball in his head, which I almost regret, as such a 

 sensible brute deserved to live." J. M. Hayward 



Sidmouth, February 9 



Circular Rainbow seen from a Hill-top 

 Climbing, several summers ago, with three friends among 

 the Coolin Hills in Skye, I was fortunate enough to witness 

 phenomena similar to those described by Mr. Fleming in last 

 week's Nature (p. 310). Our shadows were apparently thrown 

 against the precipitous side of a deep corry, distant 200 feet or 

 perhaps more. They vanished and reappeared as thin mists 

 passed through the corry, the sun shining contiimously. We 

 could not see each other's shadows unless close. The distance 

 apart at which they became visible I d i not clearly remember, 

 but know it was approximately as one of my friends, Mr. W. 

 A. Brown, writes: — "So long as we kept a few yards apart 

 each could only see his own shadow, but when t» o were within 

 arms' length a double shadow was visible to each, and on 

 getting still nearer the shadows merged into each other." My 

 es'.imate of the angle subtended by the diameter of the rainbow 

 is 15°, that of my friend 10°. He adds, however, "I may be 

 very far out in this." J. M. White 



Spring Grove, Dundee, February 5 



Referring to Mr. Fleming's letter in Nature of January 

 31 (p. 310), I would state that many years ago, before 

 Pontresina, in the Grisons, was so resorted to as it is now, I 

 walked up the Piz Languard early one fine morning with an old 

 smuggler and chamois hunter — the terms are synonymous on the 

 frontier — named Colani. On the summit of the peak is a ledge 

 of rock, on which I lay down for twenty minutes' sleep. I had 

 been asleep but a few minutes when Colani woke me, and, with 

 excuses and an expression of fright on his face, begged me to 

 come with him to see something which he had never seen in his 

 life bef jre. We moved to the w estern edge of the peak. Below 

 us were some thin clouds of mist curling about like vapour from 

 a lart^e cauldron. On these clouds appeared a circular rainbow 

 and within it, as though in a gilded frame, were two figures-^im 

 fact, the shadows of ourselves. 



"There are two of them now," cried Colani, and it was not 

 until I told him to take off his hat and wave it, as I did mine, 

 and he saw^ the action repeated by the figures, that he began 

 to feel assured they were not " Geists." It was not the " Arch 

 St. Martin," a Romansch name for a rainbow, which had 

 frightened him, though it was the first time he had seen a circular 

 one, but the appearance of the dark solitary figure had awaker.ed 

 his conscience, for some of bis smuggling adventures had nob 

 been without bloodshed. The details of the phenomenon were- 

 the same as those described by Mr. Fleming, with the exception, 

 perhaps, that the figures were more vivid and the whole spectacle: 

 of longer duration, owing to an unclouded sun. 



A similar appearance has lately been seen on the Tonja' t: 

 Range in Nevada, by Mr. R. A. Marr, of the Coast and Geo- 

 detic Survey. I subjoin his description of it, taken from a recent- 

 number of the Mail. T. R. Maynari) 



The Black Forest, February 7 



"Suddenly, as I stood looking over the vast expanse teneath 

 me, I saw myself confronted by a monster figure of a man staud- 

 ing in mid air before me, upon the top of a clearly-defined moun- 

 tain peak, which had but the thin air of the valley bebw for a 

 resting place. The figure was only a short distance from me. 

 Around it were two circles of rainbow light and colour, the outer 

 e iaintly defined as compared with the inner one, which .- 



