Sept. 6, 1883] 



NATURE 



437 



disciple of Izaak Walton 1 There was a goodly eel on the hook, 

 sure enough. 



Since then " Winifred " has once again attempted to pull out 

 the line under exactly similar circumstances. Surely this con- 

 duct sh )ws powers of observation and of inference of no mean 

 order ? 



I may add that the collie is now three years old. She saw 

 me fishing many times last summer, and, as I said before, always 

 showed great interest in what was going on. But it was not till 

 six weeks ago that I had any idea how much she was profiting 

 by what she saw. 



Perhaps some of your other readers who fish, and are accompa- 

 nied by intelligent dogs, may have observed similar instances of 

 reasoning power. Seeing to what perfection dogs can be trained 

 to take part in other branches of sport, perhips it is not very 

 surprising that here and there one should show a little apprecia- 

 tion of the leading points of the "gentle art" of angling. 



Morgan J. Roberts 



The Hollies, Cwm Newydd, Holywell, 

 North Wales, August 31 



Copper and Cholera 



Need we go to Sweden to test the theory that copper is a 

 preservative against cholera ? The year before the 1S65 epidemic 

 X travelled by train past Swansea, and my attention was called 

 to the utter want of verdure in the surrounding country, due, I 

 was told, to the copper fumes. 



Now, according to the official report, the deaths from cholera in 

 Swansea were 88 in 10,000 in 1866, in Neath 79, i 1 Llanelly, 76 — 

 all places in the same neighbourhood ; thus showing a far greater 

 mortality for the copper-smeliing district than any other in 

 England or Wales. The mortality for all England was only 13 in 

 10,000, and for London 18. The only two places which in any 

 degree approach Swansea are West Ham with 50, and Liverpool 

 with 54 ; in both of which it is well known cholera was espe- 

 cially severe. The epidemics of 1849 and 1S54 present Swansea 

 in a more favonrable light. 



Perhaps some of your Swansea readers, by giving the number 

 of deaths — if any — among the actual workers in the metal, can 

 help those who, like myself, are inclined to believe in copper as 

 a prophylactic ; in « hat v ay I scarcely know, unless it be 

 according to the principles of homoeopathy, as my experience on 

 three occasions — and a lively time I had of it — lead me to 

 believe that copper added to plums to preserve their colour 

 should be eschewed, at any rate in cholera times. 



Dulwicb, September 1 B. G. Jenkins 



The Meteor of August ig 



The same meteor was undoubtedly seen by Mr. Crispin at 

 Wimbledon, Mr. Pooley at Cheltenham, and myself at Llan- 

 dudno, and I think I can remove Mr. Crispin's difficulty. 



The apparent fall of meteors towards the earth is generally an 

 effect of perspective. An object at a great height moving directly 

 away from the observer appears to move perpendicularly down- 

 wards. If moving away obliquely to right or left, it appears to 

 have a more or less horizontal path with a downward inclination. 



This meteor was evidently not moving towards the earth, but 

 was one of those that skim the upper atmosphere, white-hot at 

 their surfaces while the resistance is sufficient, and dark ag tin as 

 soon as they pass into a thinner medium. I suppose it to have 

 first become luminous when directly over E-sex, not far from 

 Chelmsford, at a height of about seventy miles, passing north- 

 east over the sea, and vanishing near the Texel. IN appearance 

 along such a path would agree very fairly with the three ob- 

 servations, except that, if Mr. Pooley saw it first quite south-east 

 by compass, it must have been luminous for a second or two 

 before Mr. Crispin or myself observed it, and the starting-point 

 would be nearly over London. 



I was wrong at first in referring to the Yorkshire coast. The 

 visible path was clearly south of the Humber. 



Albert J. Mott 



Crickley Hill, Gloucester, September 2 



THE ISCHIAN EARTHQUAKE OF JULY 2%, 1883 

 C INCE my last letter to Nature most of my time has 

 •^ been occupied in visiting different parts of the island, 

 and although there are still a number of objects to be 



carefully examined the general features of the catastrophe 

 I hope to have cleared up. 



The actual moment of the earthquake is unknown, but 

 seems to have been about 9.25 p.m. ; so, supposing the 

 shock registered at Naples and Vesuvius to be identical 

 with that of Casamicciola, had the observation of time at 

 the latter locality been correct, we could calculate the 

 velocity of transmission, but which it is to be feared is 

 impossible. 



As mentioned in NATURE, the shock was preceded by 

 general seismic disturbances throughout Southern Europe. 

 In the island itself we have the most contradictory state- 

 ments as to premonitory signs and symptoms. One 

 gentleman noticed on two occasions previously his watch, 

 which was suspended by a nail to the wall, swing back- 

 wards and forwards. The assertion about the water at 

 Gurgitella being much hotter some days before is of little 

 value without proper thermometric observations, since it 

 is known commonly to vary 20° C, and may reach more 

 than 40° from time to time, and I am acquainted with a 

 thermal spring at Bagnoli, near Naples, that varies 23° 

 C, ranging from 13° to 36° C. Perhaps the most 

 remarkable of these kinds of statements was couched 

 in these words : — " The syndic of Serrara Fontana (a 

 town on the south of the island) telegraphed to the 

 Minister of Public Affairs to the effect that in that 

 country a fissure one kilometre long, thirty metres broad, 

 and of unknown depth, from which were issuing dense 

 columns of vapour." On reading this I started imme- 

 diately for Serrara, and there the syndic placed at my 

 disposal his two informants as guides. After a climb of 

 three hours and a half along the almost impassable sides 

 of Epomeo, we came to its northern slope over Lacco 

 Ameno, with the two landslips I had visited and photo- 

 graphed thirty-six hours after the shock. The fissures 

 were such as take place along the edges of all landslips. 

 No vapour was issuing, and its presence for a short time 

 after the earthquake could be easily explained : the 

 locality is part of the old fumarole area of Monte Cito, 

 where alum was manufactured centuries ago ; the rock is 

 much decomposed by the continual escape of acid vapour, 

 and only required the earthquake to shake it down ; 

 when the displacement took place a large surface of hot 

 and moist tufa was exposed, and no doubt for some time 

 gave off a quantity of vapour. 



It will be seen that not a single point of the size, 

 locality, and characters of the fissure described by the 

 newspaper was correct or free from gross exaggeration. 

 I have visited with care all similar sites of supposed 

 fissures, but after some days of want of shelter, sleep, an 

 abominable starvation diet of bad bread and rotten 

 cheese, combined with continual climbing from daybreak 

 to sunset in an extraordinarily hot Neapolitan summer in 

 the hope of finding some evidence of volcanic action, I did 

 not meet with the slightest success. I was accompanied in 

 these excursions by my friend, Prof. P. Franco of Naples, 

 who shared my disappointment and disgust. Holding as 

 I do the volcanic nature of the earthquake, the appear- 

 ance of any such phenomena would have been greedily 

 accepted. 



If we draw isoseismal lines over the injured districts, 

 we find that they assume the form of elongated ellipsoids 

 whose major axes run nearly east and west. 



The fourth isoseismal area, in which houses are only 

 very slightly fissured, not only includes the whole island 

 but must extend into the sea some distance. 



One remarkable fact is the manner in which the hou-es 

 of the marinas have suffered much less than others in 

 their immediate neighbourhood, or even farther away 

 from the seismic vertical. This is no doubt due to their 

 foundation reposing on sea sand, which, from the loose- 

 ness of its particles and therefore inelastic nature, acted 

 as a mattress and absorbed the earth waves. The same 

 fact is observable in all buildings that have their founda- 



