Dec. 30, 1886] 



NA TURE 



197 



Of the subject-titles in this volume, the largest is Labor, 

 under which, in 150 pages, a very complete library is 

 catalogued of some 1500 books and 10,000 articles, well 

 arranged under many headings. Under Kidney, the 

 student will probably be content to find references to 

 about 400 books and 2500 articles. 



It is easy to show the vast extent of the work attempted 

 and executed ; that there are absolutely no inaccuracies 

 in the result is hardly possible, difficult as it may be to 

 find them. The references in this volume certainly stand 

 many tests, and most of those who have made frequent 

 use of the previous six volumes in practical work have 

 acquired a confidence in their accuracy which is very rare 

 in dealing with such an immense mass of varied languages 

 and types and abbreviations so thickly interspersed with 

 figures. 



Both the Library and the Index-Catalogue are brought 

 fully up to date. The volume is presented to the Surgeon- 

 General of the LI.S. Army in a letter of preface dated 

 June I, 1S86, and it contains the books and periodical 

 references practically complete up to the end of 1S85. If 

 any comparatively modern subject is examined, e.g_ 

 kairine, we find nothing said or known of it before 1882, 

 and yet 120 references, taking us over all the published 

 literature of the subject, down to the end of 1885. 



This seventh volume includes the entries from In- 

 signares to Leghorn. It is likely to be the middle 

 volume of this encyclopedic work ; and certainly if Mr. 

 Billings is able to publish his last and concluding volume 

 in 1892 no one who has any interest in the progress of 

 knowledge will hesitate to congratulate him and his 

 colleagues even more heartily, if it be possible, than at 

 present. A. T. Myers 



LETTERS TO THE EDITOR 

 [The Editor Joes not hold himself ^sponsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake to 

 return ^ or to correspond with the writers of rejected manu- 

 scripts. No notice is taken of anonymous communications. 

 [ The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherivise to insure the appearance even 

 of comJHunications containing interesting and novel facts. ] 



Sounding a Crater, Fusion-Points, Pyrometers, and 

 Seismometers 



The account given by Prof. John Milne of his ascents and 

 attempts at sounding the crater of Asama Vama is exceedingly 

 interesting, and I can thoroughly sympathise with him in the 

 difficulties he encountered, having been exposed to them on 

 many occasions, and not always coming off so victoriously. He 

 and Mr. Dun, however, have been forestalled by the late 

 Robert Mallet. When I came to Naples some eight years since, 

 I found in one of the store-rooms of the geological department 

 of the Naples University a quantity of apparatus which I soon 

 made out the use of. 



It appears that Mallet had this apparatus made especially for 

 the purpose of measuring the temperature and studying the gases 

 and the lava itself within the mouth of the volcano Vesuvius. On 

 his arrival in Naples the state of the mountain did not permit of 

 the experiments being carried on, and the whole of the materials 

 were left in charge of Prof. Guiscardi, who could give no other 

 information than the above. By carefully studying the appa- 

 ratus I was soon able to understand Mallet's intentions and the 

 mechanism he intended to employ. There are two drums of 

 small wire cable — one for traversing the crater to hold a pulley 

 over the " bccca," xnA the other for letting down the weight 

 and crucible. The crucible is of cast iron with a bayonet-jointed 

 cover, and is, no doubt, intended to contain substances of 



different fusibilities. The apparatus is, however, an improve- 

 ment on that used in Japan, in that the sounding-rope is insu- 

 lated and there is an electrical bell and battery so arranged that 

 when the crucible enters the lava it makes an earth-contact and 

 rings the bell. There are other pieces of apparatus that I could 

 not get at, but I think they are intended for chemical 

 researches. 



From thcFC facts it will be seen that Prof. J. Milne has been 

 forestalled as far as the method is concerned, but no experiments 

 were ever carried out, either by Mallet on account of failing 

 health, or by those in whose hands the apparatus fell. I n)ade 

 application to be allowed to use the apparatus, but for various 

 reasons was unable to. 



Before leaving this subject, may I appeal to your readers for a 

 list of substances the fusion-point of which is known, and all of 

 which would be above a dull red heat ? I should like to have 

 as complete a series as possible, so as to obtain results confined 

 within narrow limits. Also any suggestions as to the be^t form 

 of pyrometer that might be forced into and helil in a stream of 

 flowing lava, and that would not be injured by the breaking off 

 of the rocky crust on its removal. 



May I be permitted to make a few observations on the ques- 

 tion lately raised about the authorship of certain seismographs ? 

 Not long since I de.=cribed in your pages certain instruments 

 that I considered as likely to be useful in such violent earth- 

 quakes as shake Ischia from time to time. With the exception 

 of two, no claim was made to originality of principle, and yet I 

 received through your pages a severe scolding from Prof. Ewing. 

 Now if we really go into theliteratureof the subject we shall find 

 the horizontal pendulum is not the invention of Prof. Ewing, 

 but his present form of seismograph is one of the best applica- 

 tions of such a contrivance for measuring the horizontal com- 

 ponent of an earth-wave, and I think lie is justified in calling it 

 his seismograph in so far as the present model goes. If we did 

 not allow so much, no man using a vertical pendulum, however 

 well contrived and modified, could call such his. At any rate I 

 shall leave Prof. Milne, Prof Ewing, and Mr. Gray to fight 

 their own battle, but Prof. Ewing has fallen into the very same 

 error of which he not long since accused me. 



Naples, December 20 H. J. Johnston-Lavis 



The Recent Earthquakes 



May I ask to be allowed to call attention to some points in 

 relation to the two earthquakes mentioned in your issues of 

 December 9, p. 127 ("Volcanic Eruption in Niua-Fu, Friendly 

 Islands"), and December 16, p. 157 (" Earthquakeat -Sea "). As 

 regards the first, it is stated that "The whole island has been 

 in a disturbed state for some three months and a half, the dates 

 of the principal disturbances coinciding remarkably with those 

 which are going on in other parts of the world — earthquakes 

 on June S and it, which, I think, are the dates of the first 

 New Zealand outbreaks. . . . This is, of course, not wonderful ; 

 but the final catastrophe here took place on August 31, which, 

 we understand, was the exact date of the recent American 

 earthquake. It was preceded for twenty-four hour; by earth- 

 quakes, and went on for ten days. " 



As-uming the synchronism of the Tonga eruption and earth- 

 quakes with thoFe of the North Island of New Zealand, there 

 is this very interesting relation between the two localities, that 

 they both lie very near to a great circle which I mav designate 

 as the "West Coast of Africa Great Circle.' This passes 

 through, or near, the following points : — 



Cape of Good Hope to St. Helena Bay ; mouth of River 

 Orange ; Walfish Bay ; Cape Mariha ; Cape Lopez Gonzalez ; 

 Bonny River ; Algerian coast, near Nemours ; south-east coast 

 of Spain, near Almanzora ; north coast of Spain (3° 25' W. 

 long.) ; west coast of Ireland (Loop Head) ; southern point of 

 Iceland (near Westmanna Island) ; north-west point of Iceland ; 

 Greenland, Cape York ; Melville Island (south coast and point 

 of) ; Bering Island ; Cape Dalhousie and coast-line of Liver- 

 pool Bay ; Ala-ka, Montagu Island ; Tonga Island (half a 

 degree to west of Tonga Tabu) ; New Zealand, north-east 

 point of North Island ; passes between Adehe Land and South 

 Victoria Land ; Enderby's Land. It may be remarked that 

 several of these localities are noted for disturbances both 

 volcanic and seismic. 



As regards the " earthquake at sea" mentioned in your num- 

 ber of the l6th inst. , the position where it was felt is given 

 as N. lat. 19° 21', and W. long. 64° 22'; this gives a point 

 about 93 miles north-east of Porto Rico. The interest in this 



