620 



NATURE 



[April 27, 1893 



the same species, the widely different results are probably due 

 to the trees furnishing the timber having been grown under 

 different conditions. Mr. Mackenzie mentions a curious fact 

 "observed in the working of the various pine timbers I have 

 named. It was found that the wood of pines having three leaves 

 in a sheath wa^, as a rule, much harder than those having only 

 two, whilst all those having five leavesinasheath were uniformly 

 soft, and when dressed had a silky appearance. So general is 

 this characteristic that one could almost at once tell to what 

 class a certain plank of pine timber belonged." These observa- 

 tions we do not remember to have seen previously recorded. 



" The Diseases of Conifers," Although in German there is a 

 literature of considerable extent on this subject, the publications 

 in English are few. Prof. Marshall Ward is a very careful and 

 competent observer, and his contribution to the report is of great 

 value both to the man of science and to the practical forester. 



Mr. W. F. H. Blandford's insects injurious to conifers 

 is an excellent rhwne of all that is known up to date of the life- 

 history of the various insect pests, which have been noted as 

 injurious to conifers. How important this subject is may be 

 judged by the destruction wrought by the larvK of Liparus 

 w/^wair/ia between 1853 and 1868 in East Prussia, Poland, and 

 Russia, where the spruce was killed over an area of 7000 square 

 German miles. A similar instance is that afforded in 1890 in 

 the Bavarian forests by the same destructive insect, the loss 

 caused by this to the revenue being estimated at ;^40,ooo. 

 Those, however, who, like the writer of these notes, travelled 

 over the districts affected during the ravages of the larvce, would 

 realise much more vividly the gravity of the attack than others 

 could from a mere perusal of statistics. 



Not the least valuable portions of the report are the stat- 

 istics of conifers in the British Islands, and the value in 

 the British Islands of introduced conifers, by Mr. Malcolm 

 Dunn. These statistics represent an enormous amount of 

 energy and perseverance on the part of the compiler. The tabu- 

 lated forms give particulars from a large number of places in the 

 British Islands, and deal with the soil, altitude, age of trees, 

 their height, girth, &c. The list of conifers and largest 

 specimen?, also by Mr. Dunn, gives the dimensions of the 

 largest specimens taken from the above-mentioned tables and 

 also.the number of returns respecting each species. G. N. 



THE EARTHQUAKES IN ZANTE. 

 T AST week we noted the fact that another disastrous earth- 

 -^ quake had occurred in Zante on Monday, April 17, and 

 that it had been followed by various slighter shocks. Accord- 

 ing to a special correspondent of the Times at the town of 

 Zante, the centre of the disturbance seems to have been under 

 the sea about two miles from land. Before the great shock 

 the inhabitants of the district of Vasilikos, near this centre, 

 heard submarine rumblinas, which increased in loudness till the 

 earthquake occurred. Two huge boulders were detached from 

 the neighbouring mountain and rolled into the valley beneath. 

 The same correspondent records that on the afternoon of April 

 21 there were several violent shocks. 



The conditions under which this series of earthquakes has 

 occurred will no doubt be carefully studied. Meanwhile we may 

 call attention to a good article contributed to the Mediterranean 

 Naturalist for April by Mr. W. G. Forster, seismologist, 

 manager, and electrician, Eastern Telegraph, Zante, on the 

 earthquakes which did so much damage in January. From this 

 paper we reprint the following historic statement : — 



" From the traditions of the place it has always been considered 

 pretty certain that Zante must invariably expect a more or less 

 severe earthquake about every thirty years. I find, however, that 

 this cycle of seismic disturbances is common to all earthquake 

 districts in south-eastern Europe and Asia Minor, and that there 

 exists also a fairly proven and established law which governs 

 these periods of visitation, for instance, whenever any long time 

 has elapsed without the slight shocks — which average one or 

 more a week in earthquake districts of non-volcanic regions— 

 and when to these periods of comparative quiescence succeeds 

 one of constant earth tremors, then a disastrous shock is nearly 

 certain to take place. This is a very important point, and can- 

 not be neglected when the question as to the origin of the shocks 

 is under consideration. 



" The last strong local earthquake previous to the present 

 series of shocks occurred on October 26, 1873, and although it 



NO. 1226, VOL. 47] 



was far less severe, it originated within a mile or" so of the 

 present one's centrum, as proven by a knot of submarine cable 

 having been then lost, buried under the immense mass which 

 fell into it, at the bottom of the sea ; and by the measurements 

 taken at the time. 



" This earthquake had precisely the same characteristics as 

 the present one, both previously and subsequently to its occur- 

 rence, and although very many severe and slight shocks have 

 been felt since 1873, in no case were they of so pronounced a 

 local nature as those just recently experienced. When the great 

 earthquake of August 27, 1886, occurred, which destroyed 

 Filiatra on the mainland to the south-east of Zante, this island 

 was fortunately outside the direct vibrative waves of seismic 

 forces radiating from the centrum of that shock ; which covered 

 up six knots of submarine cable in latitude 37°25', longitude 

 2i°ii' east of Greenwich ; but still it did considerable damage, 

 and its force was severe enough to cause the greatest alarm even 

 in so distant a place as Malta. 



"From that year until the spring of 1890 there were numbers 

 of small shocks, but after then and up to August, 1892, only a 

 very few tremors were recorded. On August 16 last year about 

 twelve small shocks suddenly occurred during the day, purely 

 local, and all from east to west. After three days of absolute 

 tranquillity they began again, and although merely pulsations 

 they were of a very pronounced character. 



" At midnight on August 27 the shock was strong, and from 

 then until the still smarter shocks of September 3 and 5 the 

 earth seemed always shaking. Another few days of quiescence 

 were followed by a renewal of shocks. This state of things 

 continued until the middle of January last — and was again 

 succeeded by a fortnight of perfect tranquillity. At 9 p.m. on 

 January 30 a very distinct rumbling occurred, which was fol- 

 lowed by a short, sharp shock, as if from some falling mass, 

 and then all was still again. I noticed after the shock a series 

 of small ripples on the sea, which was previously and 

 subsequently quite calm. The night passed very quietly until 

 5.34 a.m., local time, when the whole island began to sway 

 terrifically from east to west, with a purely undulating motion, 

 finishing up by a movement which I can only describe as 

 being similar to that of some mighty force wrenching out the 

 bowels of the earth. This shock lasted twelve seconds, and 

 its centre was undoubtedly in the sea very close to the town, 

 and due east of the same. From its apex of origin its range 

 of destruction, on the frontage of the town, was not wider than 

 two miles, spreading out to about fifteen when it reached the 

 villages at the base of the range of hills, six miles off. 



"The destructive force had a tendency to incline from 

 due east to the north-west of the island, which is 

 about 27 miles in length by an average breadth of eight, 

 a subsequent shock taking a much lower range. During 

 the whole day shocks were alarmingly frequent and numbered 

 some hundreds between the first and nightfall when everybody 

 went to the open ground in a most panicstricken condition. At 

 1.56 a.m. on February i another terrific shock took place — not 

 so severe as the first, but with a range towards the south-west and 

 of increasing destructive force. This shock lasted 20 seconds 

 and was also succeeded by numberless others. After 23 hours 

 a third severe shock occurred and periodically during the whole 

 week others of decreasing intensity took place. Since the first 

 shock until the present date, at least one thousand (including 

 pulsations and tremors) have been felt. 



"Of course the direct and indirect damage has been very 

 great owing to the extensive zone of destruction, the scattered 

 nature of the villages and to the bad construction of the houses 

 in general and to their dilapidated condition owing to extreme 

 poverty of the island. At least half a million sterling is re- 

 quired to rebuild the place, and as this amount can never be 

 realised many of the ruins are likely to remain untouched and 

 most of the population will have to emigrate." 



SCIENTIFIC SERIALS. 

 American Journal of Alathtmatics, vol. xv. i (Baltimore : 

 Johns Hopkins Press, January, 1893).— The piece de resistance 

 of this number is a memoir by Prof. Cayley on i^ymmetric 

 functions and seminvariants (pp. 1-74). in which the author 

 further develops the theory of seminvariants, and in connection 

 therewith is led to some investigations on symmetric functions. 

 The subject is treated with characteristic ability and affords 

 ample evidence of the writer's recovery from his recent serious 



