Dec. 1, 1882.] 



• KNO\A/L.EDGE 



435 



the seat of Colonel Clifford, at Llaneilio, a wall was fissured 

 by the shock. At Ashfield, near Ross, the walls of two 

 houses which were unfinished were partly thrown down ; 

 and at a place called Bishop's Wood, lower down on the 

 Wye, a house near the river was rocked with so much 

 violence that a gentleman who was asleep in a heavy old- 

 fashioned four post bed was nearly thrown out. 



Much doulit was thrown on the statement that the 

 earthquake was accompanied by a roaring noise, and the 

 editor of the C.^rJogi^t expressed his opinion that those 

 who imagine they had heard such a noise must have de- 

 ceived themsehes. But the evidence we have on this 

 point is far too clear to be discredited in this way. The 

 Rev. H. C Key, of Stretton Rectory, near Hereford, 

 compared the noise which he heard to that of " a very 

 heavy and long train rushing furiously through a station." 

 And the gentleman who was nearly thrown out of bed, as 

 above stated, relates that so violent a noise accompanied 

 the shock that he imagined an explosion of gunpowder had 

 taken place in a barge on the Wye, and he rushed to the 

 window to see what were the eftects of the supposed catas- 

 trophe. The Rev. W. S. Symonds, Rector of Pendock, 

 who wrote an interesting paper on the subject of this 

 earthquake for the Popular Science Revieic, says that he 

 received the following information from a friend, who is 

 thoroughly to be relied on : — "A man rose unusually early, 

 and was engaged loading a cart with potatoes, which he 

 had promised to deliver before his day's work commenced ; 

 when on a sudden, ' he heard a dreadful noise come roaring 

 up,' apparently from a wood to the westward, and his 

 cart rocked so violently that he was nearly thrown out of 

 it. The trees all around him rocked violently to and fro, 

 and the rooks rose cawing from the wood ; the small 

 birds also twittered, and took wing with notes of distress. 

 The thunder-like noise appeared to roll off towards the 

 east" 



That the earth was shaken with considerable violence 

 in the western parts of England during the earthquake 

 of 1863 is shown in a remarkable manner by the 

 effects experienced in Carmarthen Bay. Eight hours after 

 the occurrence of the earthquake, a large column of water, 

 shaped somewhat like a cone, and " of a dark brown 

 colour, as if charged with earthy matter " was seen to roll 

 forward into the bay. A small vessel with which this 

 mass of water came in contact, " was violently pitched 

 about, and the water thrown completely over it." 



The events recorded during the last English earthquake, 

 in 1868, had no special interest, save that which they de- 

 rived from their relation to the occurrence of a pheno- 

 menon which is so unusual in our country. The shock 

 would seem to have been one of very moderate severity, 

 since beyond the displacement of a few light articles of 

 furniture it produced absolutely no disturbance whatever 

 in the buildings which were shaken by it. No walls were 

 fissured, nothing was thrown down — in fact, nothing re- 

 mained to show that the most imposing terrestrial pheno- 

 menon known to man had been experienced in our country. 



The most interesting circumstance connected with that 

 last earthquake, and that which preceded it by a few days 

 only, in Ireland, is that they occurred during a brief ces- 

 sation of the activity of Mount Vesuvius. Tlie volcano 

 had been in violent eruption until almost the very day of 

 the earthquake in Ireland. It remained at rest for a few 

 days, but the rest was only apparent ; the mountain was 

 about to be shaken by an outburst even more energetic 

 than that which it had before given \ent to. But during 

 these few days' rest there not only occurred two earth- 

 quakes in the British Isles, but a third was experienced in 

 Wallachia. At last the energetic action of the imprisoned 



fluids and elastic vapours beneath Vesu^-ius resulted in the 

 formation of a new cone, through which enormous volumes 

 of lava forced their way. We can hardly doubt that the 

 earth-tremors e.xperienced in the British Isles were due to 

 the action of the subterranean matter which had been 

 temporarily prevented from escaping through the crater of 

 Vesuvius. 



FRENCH AND ENGLISH RAILWAY 

 SPEED. 



THE French claim to be quicker in railway travelling 

 than we are. A comparison is made by a writer in 

 Annnles Indnsiri-eUes, who takes for the case of England 

 data recently furnished by M. Gerhardt for twelve of the 

 principal English lines. M. Gerhardt distinguishes com- 

 mercial speed and mean speed. The former is that ap- 

 pearing from a comparison of the whole distance run and 

 the whole time, including stoppages ; the latter from a 

 comparison of the same distance with the real time of 

 travelling, deducting losses of time through diminished 

 speed at departure or arrival, at junctions, itc. Taking 

 express trains, it appears that the mean speed in England, 

 with one exception, exceeds 60 kilometres (37f miles) an 

 hour, and reaches or exceeds, in seven cases out of twelve, 

 63 kilometres (39 miles) ; on the Great Northern particu- 

 larly it is over 74 kilometres (46 miles). The commercial 

 speed is under 5.5 kilometres (34 miles) only in one case, 

 exceeds 60 kilometres (37; miles) in five, and on the Great 

 Northern it reaches 66 5 kilometres (4H miles). The 

 mean speed of French express trains, on the other hand, is 

 from 595 to 69'8 kilometres (37 to 431 miles) an hour; 

 the commercial speed, 52-4 to 634 kilometres (321 to 391 

 miles) an hour. A difference between the two countries of 

 at least 10 per cent, is recognised. Attention is called to 

 the fact that in France junctions must not be passed at a 

 higher speed than 20 kilometres (12|- miles) for passenger 

 trains, and 10 (6i miles) for goods trains ; hence a loss of 

 time in slowing before the junction (one minute), in 

 passage (one minute), and in regaining normal speed (one 

 minute) ; or three minutes lost at each junction. In 

 England all latitude is allowed in this matter. 



[Whatever value the metric system may have, and how- 

 ever desirable it may be to introduce it into statistical and 

 scientific literature, we cannot admire the way in which 

 some of our contemporaries — as the Times in the above 

 instance — publish statements in which the metric measures 

 are used, without any figures to show (as we have done 

 above) what are the corresponding English measures. — Ed.] 



J^ffalflUSf. 



PROFESSOR DE JIORGAN.* 



PROFESSOR DE MORGAN was great in mathematics, 

 distinguished in logic ; but he was greatest, and should 

 be most distinguished, for the protest which his life boro 

 against the Evil Doctrine of Expediency. He not ordy 

 taught the true doctrine — he practised it ; he bore witness 

 to it when witnessing to it was not the way up in the 

 world. The paths by which many as profound in science 

 as he, as well able to stand on tlieir merit, with as Uttle 



• Memoir of Aufiuslus dc Mortjan. By his Wife, Sophia Elizibetu 

 De Morgan. Witli Selections from his Letters. (London : 

 Longmans & Co.) 



