September 26, 1901J 



NA TURE 



527 



We have then the following construction. 



With K as pole, AM as asymptote, and iAC as the con- 

 stant distance, describe a branch of a conchoid on the farther side 

 ■of AM. Let B.\ cat the curve in G, then .\G is the firit, and 

 KM the second mean proportional between .\C and AB. 



I have not been able to find any more recent accounts, but 

 perhaps some others of your readers can tell whether the cissoid 

 ^tias been employed to trisect an angle, or whether it is possible 

 to solve the problem by means of this curve. An easy solution, 

 which is not given in Leslie's book, would be by means of the 

 ILiinav'on, r=a (I +2cosfl). D. M. Y. Sommerville. 



24 Balhousie Street, Perth, August 24. 



Aurorae and Meteors. 



On Tuesday, September 10, a beautiful display of the curtain 

 Aurora Borealis was observed here at 9.30 p.m. It extended 

 from the northern horizon to about 12", and from north-by-east 

 to north-north-west. The most brilliant part of the display 

 iasted for about ten minutes after we first observed it, and then 

 dissolved into a diftused, though vivid, glow. At 10.20 p.m. 

 the Aurora was evidently much more distant, exhibiting itself as 

 a brilliant glow above the north-western horizon. 



At 9.52 p.m., the same evening, a brilliant meteor was ob- 

 served darting towards the south-west, the line of motion passing 

 between Corona Borealis and Hercules. The maximum brilliancy 

 of the meteor was superior to that of Jupiter. At 10.45 P-™- ^ 

 meteor was observed darting past Arcturus, which was tiien about 

 3°.above the north-by-west point of the horizon. At 10.50 p.m. 

 ■(Greenwich time) a brilliant meteor darted from a point within 

 1° of a Persei in a westerly direction, leaving a broad streak. 

 Ale.\. C. Henderson. 



The Manse, Rusness, Sanday, September II. 



THE INVERNESS EARTHOUAKE OF 

 SEPTEMBER iS. 

 n^HE earthquakes of the Inverness district rank among 

 ^ the strongest ever felt in this country, bat we 

 must go back nearly a century to find one that surpassed 

 the recent shock in intensity and extent of disturbed area. 

 That of August 13, 1S16, of which Sir T. Dick Lauder's 

 brief but graphic account is the chief memorial left to 

 us,' damaged several buildings in Inverness, and was 

 felt over the whole of Scotland. .After this, no shock of 

 much consequence occurred until that of February 2, 

 1888, which was felt so far as Edinburgh and Glasgow 

 and was perceptible over a district the area of which is 

 estimated at about 15,000 square miles.- The earthquake 

 of November 15, 1S90, was slighter still ; buildings were 

 practically uninjured by it, and its disturbed area did not 

 exceed 7500 square miles.-' In all three cases the epi- 

 centre lay close to Inverness and not far from the northern 

 boundary fault of the Highland district, and it is, there- 

 fore, natural that movements along this fault or system of 

 faults should be held responsible for the origin of the 

 earthquakes. 



The shock of last week occurred shortly before 1.30 a.m., 

 and thus it is possible that we may never know the full 

 extent of its disturbed aret. It does not seem to have 

 been noticed in either Edinburgh or Glasgow, but the 

 southern limit of the area cannot have lain many miles 

 north of the line joining these cities, for the shock was 

 certainly felt along the south coast of Fifeshire. Most of 

 the rest of Scotland must have been sensibly shaken, for 

 we have records from places as far north as Wick, in the 

 west of Mull, and all along the east coast of Aberdeen- 

 shire. 



In Inverness the damage, though never serious, is con- 

 siderable in amount. There is scarcely a street in the 

 to\yn which has entirely escaped. In a few houses, 

 chimney-stacks or parts of them fell down, and many 



1 Quoted by D. Milne, EJin. Neiu Phil. Jount., vol. xxxi. 1841, pp. 

 116-117. • ■ ■ 



- C. A. Stevenson, Edit:. Roy. Soc. Proc, 1888, pp. 260-266. 

 3 Quart. Joiirn. Geol. Sue, vol. xlvii. iSgi, pp. 61S-632. 



chimney-cans were overthrown or displaced. For some 

 miles round the town similar slight damage occurred. At 

 Dochgarroch, about four miles south-west of Inverness, a 

 long crack was formed in the north bank of the Caledonian 

 canal. It is in the middle of the towing-path, in the 

 hard-packed surface, and is nearly half an inch wide and 

 about 600 yards long. 



From the accounts which have appeared in the news- 

 papers and from a few which I have already received, it 

 is possible to draw roughly an isoseismal line corre- 

 sponding to the degree 7 of the Rossi-Forel scale. 

 This is in the form of an ellipse, with its longer axis 

 parallel to the great fault and with the larger part of the 

 curve lying on the south-east side of the fault. As the 

 fault hades in this direction, it is exceedingly probable that 

 a slip along it at no great depth gave rise to the recent 

 earthquake. 



The stronger Inverness earthquakes generally occur 

 without the warning of preliminary shocks, but are 

 followed for some time by weaker movements. Three at 

 least occurred on the morning of the iSth, and it is not 

 unlikely that for another month or so slight shocks may 

 be felt in and around Inverness before the earth's crust 

 there is once more brought to rest. 



CH.\RLES D.A.VISON. 



NO. 1665, VOL. 64] 



DR. J. L. W. THUDICUM. 



T^HE death of Dr. Thudicum removes from our midst 

 -'■ the living equivalent of a very familiar name. .As 

 a worker, to the younger generation of men of science he 

 was not known, but some of his numerous communications 

 upon topics extraordinarily varied can scarcely have 

 escaped the observation, and have most probably rereixed 

 the serious attention, of almost every one interested in 

 the medical sciences. More than half a century ago he 

 graduated in medicine at Giessen. Almost immediately 

 afterwards, stimulated by the work and magic influence 

 of the great Liebig, who had attracted to the quiet and 

 secluded university a bevy of young men eager to become 

 adept in methods which, in the hands of their great 

 master, had forced Nature to yield up truths of such 

 momentous importance to physiology, Thudicum began 

 to work at physiological chemistry. 



Shortly afterwards he settled in this country, took a 

 medical qualification and began to practise. It must be 

 admitted that he established himself in London at an 

 opportune moment. The application of e.xact chemical 

 method to physiological, and certainly to pathological, 

 phenomena was then in its infancy. The pupil of Liebig, 

 trained in the methods of the Giessen laboratory and 

 possessed of a practical knowledge of disease, had acres 

 of virgin soil to cultivate. His power was soon appreci- 

 ated ; in 1856 he became physician to the St. Pancras 

 Dispensary, and in 1S58 lecturer to the Grosvenor Place 

 School of Medicine. In 1865 he was appointed lecturer 

 on pathological chemistry at St. Thomas' Hospital and 

 director of a newly founded chemical and pathological 

 laboratory there, obviously a position with immense 

 opportunities. 



His studies soon received official recognition, in that 

 Sir John Simon, the principal medical officer to the 

 Privy Council, engaged him in 1864 to undertake a 

 series of researches upon pathological chemistry. 

 Thudicum's results were embodied in reports which 

 were published as appendices to the reports of the 

 medical officers of the Privy Council and Local 

 Government Board, and continued to appear at various 

 dates down to 1882. .-Vlthough no doubt a mass of con- 

 stant work was embodied in these reports, they were not so 

 fruitful in practical results as was anticipated, or perhaps 

 it would he fairer to say, the tremendous achievements 

 shortly afterwards of bacteriology in this depa:rtment o 



