328 



NATURE 



[August 2, 1883 



destructive action of an earthquake. For example, we 

 find that in some cases well-built and substantial churches 

 and houses suffered severely, while crazy erections, con- 

 sidered to be almost on the point of falling to pieces, 

 received little or no disturbance. This apparent paradox 

 is of course explained by the fact that the sudden back- 

 ward and forward motions of the ground on which a 

 building stands, although they may be, and in general are, 

 of limited extent, bring very severe stresses to bear on 

 high masses of masonry, which although it may be of the 

 very best construction has little strength to resist the 

 strains produced ; while more loosely put together, and, 

 in ordinary circumstances, insecure structures are capable 

 of yielding to the necessary extent and escape unharmed. 

 Again, when an earthquake consists of approximately 

 periodic movements of the ground, buildings or parts of 

 buildings, whose natural period of free oscillation coin- 

 cides with, or is some multiple of the period of the dis- 

 turbance, yielding to the repeated and conspiring impulses, 

 oscillate with increasing range, until return to the equi- 

 librium position is no longer possible and they collapse 

 in ruins. 



A phenomenon observed in connection with many other 

 earthquakes, the rotation of upright pillars such as grave- 

 stones and monuments, on their bases, was very remark- 

 able in this. Herr von Prudnik does not accept the 

 explanation which has been offered by Mallet and others 

 that the rotation is due to vorticose movements of the 

 earth's surface ; and he offers an explanation which, 

 though not quite clearly put dynamically, seems to point 

 to the true theory. The cause of the phenomenon no doubt 

 is that the first sufficiently severe shock causes the body to 

 tilt over in the direction from which the shock proceeded, 

 and immediately after, the shock, although rectilinear in 

 direction, makes the body turn round on the corner or por- 

 tion of an edge on which it for the moment rests. This 

 explanation has been tested with model gravestones and 

 obelisks placed on a table, which could be shaken so as 

 to imitate the motions of the ground during an earth- 

 quake, and found to answer perfectly. 1 The circumstance 

 that in the earthquake at Agram, as elsewhere, the grave- 

 stones at one particular place were for the most part 

 rotated in one direction accords well with this explanation, 

 as no doubt the gravestones there were all set so as to 

 face in one direction. 



Herr von Prudnik is not of opinion that the earthquake 

 was due to volcanic agency, but thinks that it was pro- 

 duced by the yielding to mutual stresses of the materials 

 underlying the Slamen mountain, which lies along the 

 middle of the area in which the destructive effects were 

 most marked. This mountain occupies an area roughly 

 elliptical in shape, about 4/5 kilometres (6 Meilen) long 

 by 3 kilometres broad, and is composed for the most 

 part of slate, limestone, and dolomite surrounded with 

 strata consisting mainly of marl. To this mountain all 

 the effects point as the locality in which the earthquake 

 originated ; but here again we think the use of self- 

 registering seismographs would be of great service in 

 giving definite information. This would also give most 

 valuable information as to the velocities of propa- 

 gation of earthquake motions in strata of different mate- 

 rials. In the present case the disturbance travelled from 

 Agram to Vienna in twelve seconds, which gives a velocity 

 of propagation of 2 '2 kilometres per second. It is not 

 stated, however, how the exact times were observed. 



Among the details of the many interesting phenomena, 

 we find a very careful account of an outbreak of " mud 

 volcanoes" at Reznik, a place about 8 kilometres west- 

 south-west of Agram ; but for details as to this and many 

 other important points, we can only refer our readers who 

 are interested in seismology to the memoir, which will 

 well repay perusal. 



1 Vide Milne and Gray on " Earthquake Observations and Experiments," 

 Phil. Mag., November 1881. 



NOTES 

 We are enabled to give the text of the telegram received in 

 Stockholm this week from the Swedish circumpolar observation 

 party, which has wintered at Spitzbergen. The news is the first 

 received from the expedition since October last : — " Cape 

 Thordsen, July 4th, 1S83. This message will be forwarded to- 

 morrow to Capt. Startschin with the boat fetching our first mail 

 this year. The wintering of the expedition has in every respect 

 been attended with success, particularly as the scientific re- 

 searches have throughout been carried on exactly in accordance 

 with the regulations formulated by the International Polar Com- 

 mission. Hydrogra pineal and magnetic studies have also been 

 pursued on the ice in the Ic: Fjord, as well as parallax measure- 

 ments of clouds, and observations as to the temperature of the 

 air, the snow, and the earth. The winter has on the whole been 

 mild ; the greatest cold occurring on January 2, when the ther- 

 mometer registered 35°5° C. below freezing point. Storms have 

 been few. Since September last the following buildings have 

 been erected : — A hut on a mountain at an elevation of 270 

 metres, containing the anemometer and the wind-fan, which 

 were read by a self-regi-tering electrical apparatus; two astro- 

 nomical observatories ; another magnetic hut ; a bath-house, a 

 forge, and a wood storehouse. The dwelling house and working 

 room have also been enlarged. The following game was shot 

 during the winter : 61 ptarmigans, 9 reindeer, 18 wild geese, 20 

 foxes, and some wild fowl. With continuous labour, plenty of 

 food and drink, and frequent baths, the members of the expe- 

 dition have throughout enjoyed excellent health. Descriptions 

 of the nature, our labour and life here during the wintering will 

 follow." 



At the meeting of the Scottish Meteorological Society held 

 on Thursday last week it was aim ranced that upwards of 4500/. 

 had been already subscribed to establish the Meteorological 

 Ob ervatory on the top of Ben Nevis. The subscriptions vary 

 in amount from 200/. to one penny, and the subscribers include 

 Her Majesty the Queen and all classes of her subjects, and town 

 councils and other corporate bodies in all parts of the United 

 Kingdom. The road to the top of Ben Nevis is nearly halt 

 finished. The building will lie commenced early this month, and 

 it is contemplated that the portion to be completed this season 

 will be ready at the end of October for the three observers, who 

 will begin their regular observations on November I. 



Mk. Mundella in presenting his educational budget the 

 other night had nothing but essential progress to report. The 

 cry of overworking the children was introduced by some of the 

 speakers, but Sir John Lubbock pointed out that monotony and 

 not overwork was the real weakness of the present system, and 

 that the tendency was to cultivate the memory at the expense of 

 the observing faculty. The real remedy, as he pointed out, is 

 to introduce greater variety into the elementary course, and 

 above all to make practical science teaching an essential part of 

 the curriculum. 



From a statement issued with reference to the Rollestnii 

 Memorial we learn that the total sum subscribed is 11S3/. 51. od., 

 to which is added 59/. 7s. 5</., dividends paid on sums invested 

 from time to time in Consols before the list was closed. From 

 this total have been deducted secretaries' expenses, charges for 

 printing, advertising, &c, 36/. l6r. <jii. , leaving a capital sum of 

 1205/. 15.1. 8</. invested in 1200/. Three per Cent. Consols. This 

 sum has now been transferred to the chancellor, masters, and 

 scholars of the University of Oxford, and accepted by them as 

 tin' Rolleston Memorial Fund. The fund, it has been decided, 

 will be expended in the institution of a prize to be awarded 

 every two years for original research in any subject comprised 

 under the following heads : — Animal and Vegetable Morphology, 

 Physiology and Pathology, and Anthropology, to be selected by 



