August io, 1893] 



NATURE 



349 



" The Kojak tunnel fortunately escaped serious 

 damage, though it is interesting to hear that the water- 

 supply from some springs which issue inside the tunnel 

 and which now escapes in a regular drain from the 

 western (or Chaman side) of the tunnel, was considerably 

 increased after the earthquake shocks. 



" The block-house which defends that entrance to the 

 tunnel received some slight damage in the shape of 

 cracks which have appeared in the solid masonry. 



" The effects of the earthquake shocks are visible 

 almost all along the made banks on which the permanent- 

 way is laid between the tunnel and Sanzal station. In 

 their case the earthquake acted most beneficially, inas- 

 much as the artificially built-up material of these banks 

 was well shaken down, and, though the latter had sunk 

 here and there and cracks have appeared in places, their 

 settling down and consolidating was equal to a season's 

 rain, as the engineer of that section reports. 



"The real interest of the earthquake, however, centred 

 in the damage done between Sanzal station and Old 

 Chaman. 



" The line of railway descends to New Chaman from 

 the Kdjak tunnel in several great curves and in zigzag 

 fashion. Sanzal station is situated near the upper 

 margin of a great and rapidly descending glacis, which 

 slopes down from the Kdjak range to the great plain in 

 which New Chaman is situated. 



" About half a mile west of Sanzal station there is a 

 path~ which runs from the Khwdja Amran peak (8864 

 feet) in a north-northeast direction along this glacis. It 

 appears that at the immediate foot of the Kojak range 

 a great number of springs rise, close to which of course 

 there is always a certain amolint of grazing to be found, 

 and thus this line of springs has been connected by a 

 regular path, made by flocks passing along these patches 

 of pasture-land. The water escaping from these springs 

 has furrowed and denuded the glacis into an infinite 

 number of small channels. Another feature is that 

 the path with its springs and patches of grazing 

 grounds all lie as it were in a natural depression, run- 

 ning parallel with the range of the Kojak itself, whilst 

 immediately to the westward of it the ground of the 

 glacis rises somewhat, before finally descending to the 

 plains. This is well marked near Old Chaman, the foot 

 of which is built on this rising ground. 



"About seven to eight miles south of Old Chaman 

 this insignificant rise of ground becomes an auxiliary 

 range of hills, which runs west and parallel with 

 the K6jak range towards the Khwdja Amran peak 

 itself. 



" I expect to have further opportunities of geologically 

 examining this ground when the weather will permit in 

 the spring ; until then I will only state my belief that the 

 present path which connects the springs described 

 indicates, as near as can be, the existence of an old fault- 

 line. At the present time I have no further proof for 

 it than this, that as far as I have been able to ascertain 

 during this hurried visit, the line of path is, roughly 

 speaking, also a geological boundary between the slaty 

 formation of the Kdjak and a grey earthy limestone, the 

 latter of which is very probably of upper cretaceous or 

 lower eocene age ; this boundary being here suspiciously 

 abnormal in appearance. The springs which rise along 

 it tend further to the opinion that they appear along a 

 line of dislocation, which view is further strengthened 

 by the fact that in the neighbourhood of the springs not 

 only a kind of travertine is visible, but a curious breccia, 

 consisting of debris of both the limestone and the 

 slates of the K(5jak and cemented by calcareous rock, is 

 in situ and in strong force all along the line of path, but 

 not off it, which breccia I now look upon as a fault-rock. 

 The glacis itself is chiefly made up of recent deposits, 

 fans from the range above, but I hope to discover a 

 NO. I 24 1, VOL. 48] 



more exposed section further south, where the structure 

 of this dislocation, if it is one, will be clearly demon- 

 strated. Finally, but not least, the fault seems to be 

 proved by the earthquake itself, which has originated in 

 a further, though slight, dislocation along a line which 

 exactly and absolutely coincides with the present path 

 connecting the numerous springs. 



" In my theory explanatory of this earthquake, I there- 

 fore start with the assumption that an old line of fault 

 exists, which runs more or less parallel with the Kdjak 

 range itself. In a mountain range entirely formed by 

 flexures, which chiefly correspond to the strike of the 

 range itself, such faults usually exist on a large scale. 

 The lateral pressure which caused the folding of the 

 strata in such cases frequently results in one or several 

 systems of dislocations, as we may observe in numerous 

 instances within folded mountain ranges. . . ." 



" From the foregoing it would appear that the process 

 of contracting and folding, with resultant dislocations, 

 of this area in Baliichistdn, is still proceeding. At some 

 previous date in the history of the Khwdja Amran 

 Mountain range this process of compression, as it must 

 have been, has led to the formation of the line of fault 

 conjectured in these notes ; the process, from whatever 

 cause, is still active, and the tension having become too 

 great has further resulted in a slight increase to the amount 

 of dislocation already in existence. The two areas adjoin- 

 ing the fissure have moved about eight inches vertically 

 and a couple or more feet horizontally from each other, 

 which sudden establishment of a temporary equilibrium 

 in this tension is no doubt quite sufficient to account for 

 the vibration of the ground to a considerable distance, 

 which vibration is commonly called an earthquake. 



" I need scarcely say that there is no indication of any 

 kind which would point to the existence of volcanic activity 

 at, or anywhere near, the area affected by this earth- 

 quake ; I mention this only, because it was also in this 

 case, as in other instances elsewhere, the popular theory 

 advanced by many of those who personally experienced 

 the alarming symptoms of this perfectly natural phe- 

 nomenon." 



o 



SCIENCE IN THE MAGAZINES. 



F the August magazines the strongest in articles of 

 scientific interest is the Fortnif^htly Review. Under 

 the somewhat misleading title " The Wanderings of 

 the North Pole" Sir Robert Ball contributes a rather 

 diffuse article descriptive of the variations of latitude ; 

 adopting Mr. Chandler's conclusion that the earth's 

 instantaneous axis of rotation revolves about that of 

 maximum moment of inertia, with a radius of thirty feet, 

 measured at the earth's surface, in a period of 427 days. 

 This result is expressed by Sir Robert Ball in the follow- 

 ing language : — 



In that paliBocrystic ocean which Arctic travellers have de- 

 scribed, where the masses of ice lie heaped together in the 

 wildest confusion, lies this point which is the object of so much 

 speculation. Let us think of this tract, or a portion of it, to be 

 levelled to a plain, and at a particular centre let a circle be 

 drawn, the radius of which is about thirty feet ; it is in the cir- 

 cumference of this circle that the Pole of the earth is constantly 

 to be found. In fact, if at different times, month after month 

 and year after year, the position of the Pole was ascertained as 

 the extremity of that tube from which an eye placed at the 

 centre of the earth would be able to see the Pole of the heavens, 

 and if the successive positions of this Pole were marked by pegs 

 driven into the ground, then the several poshions in which the 

 Pole would be found must necessarily trace out the circumfer- 

 ence of the circle that has been thus described. The period in 

 which each revolution of the Pole around the circle takes place 

 is about 427 days ; the result, therefore, of these investigations 

 shows, when the oh-^ervations are accurate, that the North Pole 

 of the earth is not, as has been so long supposed, a fixed point. 



