January i i, 1894J 



NA TURE 



245 



cially by some indication of such piles of raw material 

 for discussion as have been accumulated by the Fishery 

 Departments of many governments. A compilation of 

 this sort depends for its value on its completeness, as the 

 reason for adopting one theory or classification rather 

 than another must be the outcome of an attempt to weigh 

 evidence. After a brief discussion of the conditions of 

 life, there follow sections on the life-districts of the 

 ocean, Hajckel's classification of marine organisms, a 

 concise discussion of the influence of light, temperature, 

 salinity, tides, waves, and currents on marine life, and a 

 short statement of the flora and fauna of the littoral, 

 shallow water, estuarine, open sea, deep sea, and oceanic 

 archipelago divisions, concluding with a few pages on the 

 geological changes of ocean basins. 



It would be premature to express an opinion of Prof. 

 Walther's contemplated work. The sketch he gives of 

 its plan stimulates interest and curiosity, and we can 

 heartily congratulate him on the orderly way in which he 

 has collected and laid down the building-material, while 

 we wish him success in his labours. 



LETTERS TO THE EDITOR. 



{ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to returft, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part tf/ Nature. 

 No notice is taken of anonymous communications. '[ 



Correlation of Solar and Magnetic Phenomena. 



The opinion of Mr. Whipple, quoted at p. 2 of Nature 

 for November 2, to the effect that the solar outburst observed 

 by Messrs. Carrington and Hodgson on September i, 1859, 

 was not the cause of the coincident magnetic perturbations, cor- 

 responds to tny own conclusion in regard to the matter based 

 upon evidence of an altogether different character. There was 

 a recurrence of strong magnetic perturbations and auroras 

 twenty-seven days later than the great magnetic storms of 

 August 28 and September i, 1859, thus following the general 

 rule which is found to apply in such cases, there being a well- 

 marked periodicity of such outbreaks at this precise interval 

 corresponding to the time of a synodic rotation of the sun. Such 

 recurrence manifestly could not exist if outbreaks upon the sun 

 were able to produce terrestrial magnetic effects indifferently 

 in all locations. In order that there may be recurrence at the 

 synodic period the magnetic effects must proceed from the sun 

 at some particular angle exclusively, and fortuitous outbursts 

 elsewhere, no matter how violent, must fail to have any per- 

 ceptible effect. In the estimation of the writer there is no 

 point more important in connection with solar physics than the 

 determination of this period and this angle with the greatest 

 accuracy possible. M. A. Veeder, 



Lyons, N.Y., December 26, 1893. 



My letter in Nature (vol. xlix. page 30), amongst other 

 interesting communications, has brought one from Mr. Law- 

 rance (vol. xlix. page loi) and the accompanying letter from 

 Dr. Veeder. Mr. Lawrance's graphic account well describes 

 the circumstances attending the manifestation of 1882 (Novem- 

 ber 17). The magnetic disturbance which broke out at 10 a.m. 

 on that day set us all on the look-out for aurora in the evening. 

 Neither were we disappointed ; the display was remarkable. 

 But the question in this case, as with the Carrington-Hodgson 

 and Young instances, is still whether the solar and magnetic 

 phenomena were directly related or simply coincident. This 

 cannot be said to be determined, and nothing less than proof, 

 in so important a matter, will serve. Better to advance surely 

 if slowly towards truth, rather than accept too hastily evidence 

 that is incomplete. We must remember that on the occasion 

 of the solar disturbance seen by Trouvelot, the magnets were 

 especially quiet, not only at the time but also before and after. 

 But any explanation of these phenomena must include all cases. 

 Theposition ofthings, as stated in my first letter, referred to above, 

 still I consider holds, qualified only by the circumstance that 

 instead of one presumed case of direct relation, three are now 

 adduced, with a fourth case (the Trouvelot observation), which 

 unquestionably was not accompanied by magnetic disturbance. 



NO. 1263, VOL. 49] 



If we further consider that, since the year 1859, when attention 

 became distinctly drawn to this question, there has occurred mag- 

 netic movement, equal to and in very many cases far exceeding 

 that accompanying the Carrington-Hodgson observation, on 

 some 400 different days, we see on how slight a foundation the 

 presumption for direct relation, that is of a nature more or less 

 instantaneous in action, exists, although the general relation 

 between the two classes of phenomena remains undoubted. 



Dr. Veeder, from his own point of view, supports the con- 

 tention that the 1859 solar outburst cannot be taken as causing 

 the accompanying moderate magnetic movement ; indeed there 

 was far greater movement some three days previously, and 

 again early on the morning of the following day ; but in regard 

 to his affirmation that there exists a well-marked periodicity in 

 magnetic outbursts corresponding to the period of the sun's 

 rotation, whilst this in a limited sense may be in some degree 

 true, I cannot say that my personal acquaintance with magnetic 

 records during very many years enables me at present to 

 accept such conclusion as a general one, or indeed what as a 

 consequence follows, that anything really depends on theposi- 

 tion in rotation which the sun occupies relatively to the earth. 



The whole subject is, however, exceedingly interesting, and 

 various considerations arise. One bearing on the present ques- 

 tion may be mentioned. Great terrestrial magnetic disturb- 

 ances are evidently in character cosmical, produced, it would 

 seem, or stimulated, by some external cause. For it has been 

 shown (Froc. Roy. Soc. vol. Hi. p. 191) that, on occasions of 

 unusually sudden magnetic disturbance, the commencement of 

 disturbance, at places so widely separated on the earth's sur- 

 face as Greenwich, Pawlowsk, and Bombay, is simultaneous 

 within a much smaller limit of time than had before been sup- 

 posed. Such sudden simultaneous action would thus appear to 

 indicate an impulse, solar or otherwise, from without, but 

 whether one distinctly solar, or in what other way produced, 

 is a question yet to be determined. William Ellis. 



Greenwich, January 6. 



The Mendip Earthquake of December 30-31, 1893. 



I submit the following notes for the useofany of your readers 

 who may be collecting information on the subject : — 



So far as I can judge, from statements obtained directly from 

 inhabitants of the locality, and from the experiences of various 

 persons, recorded in the Shepton Mallet J oiirnal oi January 5, 

 the movements in this earthquake occurred chiefly along the 

 south flank of the Mendip Hills between Shepton Mallet on the 

 east-south-east, and Draycott (near Cheddar) on the west-north- 

 west. The shock extended as far southwards as Evercreech and 

 West Pennard ; it reached as high up as Priddy, which is near 

 the axis of the hills, and was also noticed at Chewton, several 

 miles distant on the northern flank. 



The force of the shocks appears to have been very irregularly 

 distributed, in some houses the movements being quite alarming, 

 while in others not far distant they weie trifling though unmis- 

 takable. Some persons failed to hear the sound, which was 

 very evident to others. Persons out of doors heard the sound 

 most distinctly, even when they felt no shock. 



A lady at Shepton Mallet, who had previously experienced an 

 earthquake in New Zealand, recognised at once what was 

 occurring, but was not in any way alarmed. She says that her 

 bed began suddenly to shake or rock, and as suddenly ceased. 

 She was also conscious of a movement of the whole house, and 

 in the sharper shock heard the furniture rattle ; but she did not 

 observe any rumbling. Anotherlady in the same housenodced par- 

 ticularly the " funny unusual sort of noise." Again, in the same 

 house a man describes the movement as resembling a wave mov- 

 ing from east to west. A school master and mistress got up under 

 the impression that the water-heating apparatus had burst. At 

 West Compton a lady in a farmhouse thought from the sound 

 and movement "that some one was about the house, or that a 

 barrel of cider had burst." At Westbury-below- Wells the shock 

 was sharp enough to cause alarm. 



The policeman on duty at Shepton Mallet very naturally re- 

 ferred the sound to the direction of the Midland Railway, which 

 runs high on the hills in such a way that the rumble of its trains 

 is heard at a great distance. It is well known that we have but 

 little certainty in localising sounds, especially if of indefinite 

 character, and that we usually refer them to positions whence 

 we expect them. 



The area in which the earth-movements seem to have been 



