476 



NATURE 



[March 20, 1902 



we learn that the number of earthquakes was 169 as against 

 190 noted in 1S99 and 209 noted in 1S98. To obtain these 

 records the empire has been divided into sixteen districts, each 

 district having its referee. Dalmatia, for example, has 423 

 observers, who send their observations — unfortunately for the 

 editor— in at least three ditlerent languages, to Prof. .\. Hclar 

 in Laibach 



There are five horizontal pendulum stations, four of which 

 receive^ from the Government a yearly subvention of 1000 to 

 ilooK. A sixth station is to be installed at Pribram, one 

 instrument to be on the surface and another at a depth of 

 1 100 m. in the Adalbert-Schacht. 



In part i. Dr. W. LisUa gives a catalogue of records 

 obtained between June 1899 and December 1900 from a three- 

 component seismograph installed at Lembarg. From the 

 introduction to this work it is clear that Dr. Laska has met with 

 troubles, some of which might certainly have been avoided had 

 he been acquainted with the experiences of his predecessors. On 

 the second page we learn that the clock employed to drive the 

 record-receiving photographic film has also been employed to 

 give time marks on the same. To expect a time-piece to unroll 

 a heavy band of paper or to turn a drum and at the same 

 time to keep a chronometer-like rate is a false economy in which 

 those who construct seismographs for the first time frequently 

 indulge. Whatever inaccuracies may, in consequence of this 

 apparent simplicity of arrangement, have crept into Dr. Laska's 

 lime determinations it was evidently his intention that what 

 eould be measured should be measured with uninipeachalile 

 exactitude. The writer has in his possession a globe which, as 

 it could not be made in England, was purchased from abroad. 

 Its scale is stated to be 1/25,823,716-814. Although Dr. Laska 

 does not aim at such exactitude, he tells us that the mirror of 

 his N.W. pendulum is 3757 m. distant from the recording drum, 

 whilst the period of the pendulum when hung vertically is 

 °*"3'5I5> ^'^ which, however, he adds that there is no certainty 

 about the accuracy of the fourth decimal. Tables which inform 

 us that O'l minute = 6 seconds, 0'2 minute = 12 seconds, 

 &c. , also convey an idea of unnecessary redundancy. 



In the working of the instrument, which is installed in a 

 cellar, a well-known bogie has been encountered. There is 

 hardly a seismologist who has not met it, and volumes suf- 

 ficiently numerous to form a moderate library have been pub- 

 lished describing its behaviour. It is a something which 

 causes pendulums to move fitfully, and many observers cling to 

 the belief that it is an actual motion of the ground and either 

 trace the same to the beating of waves on a distant shore or to 

 some other cause. The photograms showing these move- 

 ments which Dr. Laska reproduces are strikingly like those 

 obtained from observatories all over the world. Forasmuch as 

 a copious Ventilation or the burning of a gas jet in the room 

 thus haunted frequently results in expelling the intruders, my 

 own opinion is that the majority of them have their origin in 

 the movements of the atmosphere in the room rather than the 

 movement of the ground. 



To show that there may be a relationship between seismic 

 disturbances and the movements of magnetic needles which is 

 not mechanical, our attention is once more drawn to the ancient 

 story of the magnet at Pare St. Maur which at the time of an 

 earthquake was caused to move whilst a similarly formed and 

 similarly suspended copper bar reinained at rest. Our attention, 

 however, is not drawn to the possibility that these two systems 

 had very different natural periods of vibration. 



In a supplement, suggestions are made respecting the deter- 

 mination of the distance of an earthquake origin from a given 

 station from the interval which elapses at that station between 

 the arrival of the preliminary tremors and the large waves. In 

 recent reports issued by the British Association, especially that 

 for 19CX), it will be seen that not only have these suggestions 

 already assumed a practical form, but also that other subjects 

 referred to by Dr. Laska have received greater or less 

 consideration. 



Part iii. is a detailed account of earthquakes noted in German 

 Bohemia by Dr. V. Uhlig. 



In part iv. Prof. P. Franz Schwab gives the records obtained 

 from an " Ehlert " pendulum installed at Kremsmiinslcr. 

 From an analysis of the records it appears that the frequency of 

 carth<|uakes was much less between Apogee and Perigee than 

 between Perigee and Apogee. In the cooler months, especially 

 from the middle of September to the beginning of March, the 

 pendulums were frequently unsteady. The greatest disturb- 



NO. 1690, VOL. 65] 



antes, however, accompanied marked barometiic depressions. 

 These movements probably eclipsed movements due to earth- 

 quakes. 



The next number, by Dr. E. Mazelle, is a register of 146 

 records obtained from a Keubeur-Ehlert pendulum at Trieste. 



One excellent suggestion made by Dr. Mazelle is that 

 seismologists should have a uniform system in chronicling their 

 observations. 



The periods of his pendulums are taken monthly and are 

 recorded to within l/ioo of a second of time, whilst a table is 

 given to compute possible tiltings of the pendulum to within 

 i/iooo of a second of arc. 



At the end of this paper we find certain analyses of the 

 registers, relating, for example, to the monthly frequency and 

 the frequency of disturbances of different amplitudes, those 

 with amplitudes between i and 2 mm. forming 35 per cent, of the 

 total observations. 



The sixth part of these publications, by J. N. Woldrich, refers 

 to the earthquake which on January 10, 1901, shook north- 

 east Bohemia. Here and there we find reference to unusual 

 phenomena like the swaying of forests as if moved by a strong 

 wind, the increase or decrease of water in springs, and the 

 effect of the movements u])on men and the lower animals. 

 The latter, excepting the story of a man who by the shaking 

 was caused to walk in his sleep, are of the usual type. 



Most of these papers are accompanied by maps or diagrams. 



J. M. 



SCIENTIFIC SERIAL. 



The February number of the fournal of Botany contains 

 three articles dealing with mosses. The first and most interest- 

 ing paper records the finding of an Arctic species, Telraplodon 

 ff''or/«i-/t/(;/a?jV— practically a Splachnum— on Widdy Bank Fell, 

 by Messrs. E. C. Ilorrell and D. A. Jones. Its usual habitat is 

 about 70° N., and further north. — Mr. Duncan discusses the 

 occurrence of Octodiceras Jiiliaiiun:3.\oTig with Fontinalisin the 

 liiver Severn. — There is the first part of a joint paper by Messrs. 

 D. Prain and E. Baker on Indigofera species, in which it is 

 proposed to deal with the numerous synonyms. — Mr. C. B. 

 Clarke writes an appreciative article on Colonel Sir Henry 

 CoUett, who combined botany with various important adminis- 

 trative posts in India. 



In the number for March, Messrs. S. Schonland and E. G. 

 Baker conclude a series of articles on South African species of 

 Cotyledon. — Two sets of " Notes " deal with the distribution of 

 plants. The first, by C. E. Salmon, enumerates floral localities in 

 Norfolk, thereby furnishing an appendix to Trimmer's " Norfolk 

 Flora " and the supplement thereto. — The second article, written 

 by William Whitwell, relates to East Sussex. He alludes to the 

 " Notes " given by Salmon in the last December number of this 

 journal, which were more copious and referred to the whole 

 county. These two papers, with Arnold's well-known book, 

 should bring the Sussex flora up to date, more especially since 

 Mr. Salmon benefited by help from Mr. Botting Hemsley and by 

 records due to Mr. Roper.— In the supplement, Mr. Baiters once 

 again essays a catalogue of British marine Algie, which will be 

 very cordially welcomed. The " revised list" was published in 

 Ihe. -lii/ia/s of Botany, 1S90, by the same writer in conjunction 

 with Mr. Holmes. As regards localities a change will be 

 noticed ; instead of the arbitrary sections of the coast given in . 

 the revised list, specific towns, &c., are now mentioned. Prac- 

 tically the whole of this part deals with the Myxophycex, or, as 

 they are generally termed, the Cyanophycex. 



SOCIETIES AND ACADEMIES. 

 London. 

 Physical Society, March 14.— Mr. S. I.upton, vice- 

 president, in the chair. .^ paper on the thermal expansion of 

 porcelain was read by Mr. A. E. Tutton. The paper gives an 

 account of experiments made to deleimine the expansion of 

 Bayeux porcelain between 0° and 120° C. The material 

 employed was a portion of the tube used by Bedford in his 

 experiments on the expansion of porcelain between o" and 

 S30 C. Another piece of the same tube has also been used by 

 Chappuis in a series of determinations by the lizeau method 

 between 0° and 83' C. The author has woiked with an inter- 

 ference dilatometer, which pcssessts advantages o\er the Abbe 



