Sept. 19, 1884.] 



♦ KNOWLEDGE 



247 



brake is required not only to be a first-rate train-stopper in ordi- 

 nary every-day use ; but, what is far more important, it must be a 

 self-acting, life-savin<r appliance, in case of accident similar to the 

 one at Penistone. It is quite useless to suppose that the locomotive 

 engine, railway rolling stock, or permanent way, can ever be made 

 free from defects and consequent failures. During the first half of 

 the present year no less than 5G8 tyres, 171 axles, and 181 rails 

 failed, and 28 cases occm'red of passenger trains, or parts thereof, 

 leaving the rails, by which 7 persons were killed and 51 in- 

 jured. When we consider that the fearful disaster at Penistone 

 was caused by the breaking of one axle, the fact that no less than 

 171 axles broke in six mouths becomes a matter for serious reflec- 

 tion. Axles may be made of the finest materials by the very best 

 of makers, yet flaws may and do grow, which neither the closest 

 examination nor care can detect. In the same way rails break 

 without giving any warning or showing any previous flaw. Under 

 these circumstances the groat question is, What can be done to 

 mitigate or counteract the disastrous effects of these failures of 

 material, and render them as harmless as possible ? To this 

 question there is and can be but one reply — viz., the 

 adoption of a life-saving appliance in the form of a quickly- 

 acting automatic continuous brake. An express train running 

 at sixty miles an hour passes over a space of 86 feet per 

 second. If the brake can be instantaneously applied, the train 

 runs but a few feet before the retarding power comes into full 

 operation ; but in the case of a slowly acting system, which takes 

 six or eight seconds, the train runs four or five hundred feet before 

 the brake power can be brought into action, and this simply means 

 that the train is dashing along at full speed, perfectly out of control, 

 at a time when a quickly-acting system would have very materially 

 reduced the speed and minimised the danger and risk. As long 

 ago as August, 1877, the Board of Trade issued a circular to the 

 railway companies, in which the essential conditions to a good 

 brake were clearly laid down. The most important condition is 

 that the brakes are, " in case of accident, to be instantaneously 

 self-acting." To fulfil this, the brake must be what is known as 

 natomatic. A "simple" brake has no store of power, it is only 

 used when required to make a stop, and there is always the fear 

 that when it is required it will be found wanting ; and again, even 

 if it be once applied it comes "off "of itself, as was the case at 

 Penistone, just at the very moment when most necessary to pre- 

 vent the train running down the embankment. 



The General Report to the Board of Trade upon the accidents 

 during the year 1883 has just been issued, and shows that nine 

 accidents were due to want of continuous brakes, five to the want 

 of quickly-acting continuous brakes, seven to continuous brakes on 

 the trains not being connected with the engine, two to the guards 

 not being able to apply the continuous brake ; whilst in eight 

 instances the action of automatic or other continuous brakes are 

 reported to have done good service in either preventing the colli- 

 sions altogether or in reducing the shock occasioned thereby. The 

 accident near Lynn on Wednesday is a very important case in 

 point. A train ran off the line ; the Westinghouse automatic brake 

 brought it to rest without the loss of a single life. Had this train 

 been provided with a brake which did not fulfil the Board of Trade 

 •conditions, a serious disaster must have followed. Such facts 

 require no comment. Clement E. Siretton, C.E., 



Leicester, Sept. 8. Hon. Mem. A.S.K.S. 



COINCIDENCES. 



[1409] — When on ten days' leave at Agra, during the rains of 

 1875, I actually dined at mess one night with Smith, Jones, Brown, 

 and Robinson. Only nineteen men sat down to mess. Brown was 

 the General commanding the division, Jones was his Brigade-Major, 

 Smith was an oflicer of the 55th going through the garrison class. 

 I forget who Robinson was, but, as if to make the coincidence com- 

 plete, Robertson, of the Central India Horse, was also present. 



At the same time I noticed another coincidence in connection 

 mth three uncommon surnames and multiples of nine. It was as 

 follows, the names being those of three European ofiicers, the regi- 

 ments three Bengal infantry ones to which the otficers respectively 

 belonged:— Re<7ime;i<, 9th B.I., 18th B.I., 27th (?) or SCth (?) B.I. 

 Officer, Capt. Toke, Capt. Toker, Dr. Stoker. With the increase 

 in the number of the regiment there was an addition of a letter to 

 the root name. C. W. S. D. 



THE BEST FORM OF TRICYCLE. 

 [1410] — In reply to your correspondent "A. H." (13S6), I regret 

 that I have not seen or heard of a tricycle known as the Coventry 

 Compressus. It may well be that after more than 300 machines 

 have been brought out I may have missed one. The only machine 

 I have heard of as the Compressus was one made by Moore, of 

 Kennington Park. This was a convertible, with two front-steering 

 wheels. It had good points, among which were these : that it was 



very safe from capsizing, and it was a two track machine. I do 

 not think this make of machine can now be purchased. 



I have not cared for any of the Merlin Tricycles, but as many 

 different forms of machine have been brought forward under that 

 name, I do not know which form "A. H." refers to. 



John- Beowning. 



LETTERS RECEIVED AND SHORT ANSWERS. 

 E. R. I do not possess Mr. Wriglit's book, and, in the absence 

 of the context, speak with some hesitation. If, though, we take a 

 crystal of Iceland spar and tilt it in a certain direction, a dot of 

 ink or a spot of light, as viewed through it, appeals double; but as 

 we turn the crystal the two images, after separating to a fixed 

 distance, begin to approach, and ultimately coincide. This being 

 understood, if we view the two images through a second crystal in 

 a certain position, each of such images suffers duplication, givinf 

 four. If, now, we turn crystal No. 1 round until its images are fused 

 into one, this one becomes only two in the second crystal, and on the 

 second crystal assuming a proper position the two images in it become, 

 as in the first case, united in one. — A. Z. For" the full meaning " 

 of Protoplasm and Bioplasm you must consult the works of 

 Professors Huxley, Haeckel, and others. — C. Donovan. Thanks for 

 proffered articles, but Ferrier and others have conclusively shown 

 that the Phrenology of Gall and Spnrzheim is absolutely baseless. 

 See Carpenter's " Mental Physiology," Bastian's "Brain as an Organ 

 of Mind," &c. — Nath. Alcock. If you like to send a short precis 

 of your views on the subject of the " Colours of Tropical Man," I 

 shall be glad to print it, but I cannot merely reproduce what has 

 appeared in contemporary columns. — John Howell. Thanks; but 

 such a poem as you forward is wholly unsuitable for these columns. 

 — T. Beown. "The Stars in their Seasons" is published by Long 

 mans & Co., London. — J. 0. Lind.say. Many thanks. — GfERY. 

 Such halos as you describe round the moon are caused by the re- 

 fraction of her light through a mass of minute ice-spicules, formed 

 in the region of the cirro-stratus clouds some 20,000 ft. high. If 

 you measure the angular diameter of such halos, you will find 

 that they generally have a radius of about 22'. The brush-like 

 appearance may have been caused by more opaque intermediate 

 clouds of small size intercepting the moon's light, in a way akin to 

 what happens when — as the country people say — " the sun is draw- 

 ing water."— De. E. Grotii. Forgive me if I say that I cannot spend 

 an hour or two in plodding through my astronomical bookshelves. 

 I may just ask you (after taking down a very few books at 

 random) to see Newcomb in " Monthly Notices of the R.A.S.," 

 Vol. XXL, p. 55, and the same author's "Popular Astronomy;" 

 also Beckett's " Astronomy without Mathematics." I have a much 

 more detailed mathematical disproof of Olbin theory somewhere, 

 but I am unable to light upon it just now.— Thanks. The colours 

 produced by absorption are not simple, and the chances are that 

 your " blue " glass was of a purple tint. The eye, too, is far from 

 being achromatic. To definitely answer your question the lantern- 

 glass should be examined by the spectroscope. No doubt particles 

 of sand or dust might be compressed into solid blocks by pressure ; 

 but no theoretical answer can be given as to the amount of that 

 pressure, which must be the subject of direct experiment. — 

 ANONVMors. Do you seriously suppose that I am going to notice a 

 tract which speaks of men of eminence and honour in the medical 

 profession as " the real wire-pullers — the Simons, Corys, Seatons, 

 and similar discredited and mischievous blunderers" ? If blatant 

 abuse were argument, Anti- Vaccinators must have had it all their 

 own way long enough ago. — Boreas. No one replied to your 

 query,, and I was unable to do so myself. I cannot believe "that 

 your jVu-rf'e.^prie would be anymore successful in eliciting infor- 

 mation.— Ja.\ies Shone. If you refer to page 437 of the previous 

 (5th) volume, you will find there an almost complete answer to 

 your question. I have every faith in the institution, and am fully 

 assured that every honestly competent pupil may rely upon se- 

 curing good employment, more especially if foreign' service is 

 agreeable. You might, however, learn this and more by paying the 

 place a visit. — Dr. J. G. Davey sends me a pamphlet intended to 

 show (from mesmeric experiments!) that Gall and Spurzheim's 

 phrenological system of mapping the brain is the only true one ; 

 and that the experiments of Ferrier, &c., and the opinions of all the 

 most eminent modern psychologists are worthless. He must not be 

 angry with me if I say that he has wholly failed to convince me of 

 this, — D. Sutherland Thanks, but rather outside the range of 

 subjects embraced by this journal. — F. Minter. Will be resumed 

 in due season. — T. Common. I would gladly insert your really 

 admirable letter ; but if you only knew what piles of (unprinted) 

 correspondence the subject has brought, you would pity as readily 

 as you would excuse me. — W. T. Lynn. You are perfectly right. 

 The " it " was, at least, as ridiculous as it appears in either of your 

 illustrations. See this week's " Gossip." — C. E. S. The " Bab 

 Ballads " originally appeared in Fun. 



