December 2, 1895.] 



KNOWLEDGE 



261 



AN ILLUSTRATED 



MAGAZINE OF SCIENCE 



SIMPLY WORDED— EXACTLY DESCRIBED 



LONDON : DECEMBER 2, 1895. 



CONTENTS. 



^ PAGE 



The Krakatoa Eruption. By Rev. E. Rattenbubt Hodges. 



{lllusfrated) 265 



The Golden Eagle 269 



The Filtration of Water.— II. Bv Samuel Rideal, D.Se. 



Lond., F.I.C., F.C.S ' 270 



Whip-Scorpions and their Ways. By R. I. Pocock. 



{Illustrated) " 272 



Notices of Books 274 



Aerial Warfare. By Thomas Moy 276 



Science Notes ... .. ... ... ... ... . . 276 



Letters : — Alfred J. Johnsos ; Fx Tieil Etudiaxi 



(Illustrated) ; J. Willis, Ph.D. (^Illustrated) ; T. (Illus- 

 trated); Isaac Robeets ... 277 



New Stars. By l)r. A. Beesiee, Jim. 278 



The Exterior Nebulosities of the Pleiades. By Miss 



A. 51. Gierke. (Illustrated) 280 



On the Exterior Nebulosities of the Pleiades. By 



Prof. E. E. Barnard .'. 282 



Spectrum Analysis. — III. Bv ■!. J. Stewakt, B.A.Cantab., 



B.Sc.Lond. {Illustrated) ' 282 



Mistletoe and Mistie Thrush. By Graham W. 



Murdoch ... ... ... ... ... ... ... 284 



Some Recent Patents. (Illustrated) 285 



The Face of the Sky tor December. By Heebeet 



Sadler, F.R.AS 286 



Chess Column. By C. D. Locock, B_1.0xon 287 



EDITOT^TAL NOTE. 



With the commencement of the New Volume for 1896, 

 Knowledge will revert to its original Title, " An 

 Illustrated Magazine of Science, Literature and Art," 

 which it bore as founded by Mr. Proctor fifteen years ago. 

 The title implies a somewhat extended area of woi-k, and 

 it is hoped that the Magazine will thus afford its readers 

 even greater interest in the future than it has in the past. 



With the January Number will be presented the first 

 coloured Astronomical Plate ever issued in Knowledge. 

 This will take the form of a coloured drawing of the Planet 

 .Jupiter, which has been executed by Mr. N. E. Green, and 

 reproduced by a special process. The Number will also 

 contain, amongst other Articles, a valuable Paper on 

 " Scientific Geography in England," by Dr. H. R. Mill ; 

 and the first of an interesting series of Illustrated Papers 

 on " Waves," by Mr. Vaughan Cornish. 



Arrangements have been made for a succession of 

 important Papers in the New Year ; comprising a series of 

 articles by Mr. Theo. G. Pinches on Akkadian and Baby- 

 lonian Antiquities ; Mr. E. Lydekker, on Fur-bearing 

 Animals ; Mr. H. B. Walters, on Greek Art ; Mr. J. Pent- 

 L.\ND SinTH, Mr. Botting Hejisley, and other well-known 

 writers, on Botany ; and Mr. G. F. Hill, on English and 

 ItaUan Medals and Coins. 



In Astronomy and Natural Science in all its branches 

 the Magazine will seek to maintain its present excellence ; 

 while numerous Articles will be furnished from time to 

 time, both by old contributors and new writers, upon 

 subjects connected with Science, Literature and Art. 



THE KRAKATOA ERUPTION. 



By Rev. E. E.\ttenbury Hodges. 



ONE of the fairest regions of the world is the Malay 

 Archipelago. Here Nature is prodigal with her 

 gifts to man. Here the cocoa, palm, cinnamon 

 and other trees flourish, and rice, cotton, the 

 sugar-cane and tobacco yield their increase under 

 cultivation. But, beneath these scenes of loveliness, there 

 are terrific energies, for this region is a focus of intense 

 volcanic action. In it a line of volcanic action is marked 

 by the great vents of Pajung in Java, the cone of Princes 

 Island, Krakatoa, Sebesi and Rajah Bassa in Sumatra, 

 and in the Sunda Straits two such lines of volcanic action 

 would seem to cross each other (Fig. 1). The evidence for 

 this seems to have been furnished by the eruption of 

 Krakatoa in 1883. 



Fig. 1. — Sketch Map, showing the supposed lines of volcanic action. 



After providing for the safety and relief of the survivors, 

 the Dutch Government ordered a fresh survey of the 

 Straits, and then resolved upon a scientific investigation 

 of the facts pertaining to this eruption. A commission 

 was appointed in October, 1883, and Dr. Yerbeek, already 

 well known as an experienced scientific surveyor of those 

 regions, was able to give his valuable services. The 

 report of their proceedings appeared in February, 1881. 

 At about this time, the French Government sent out two 

 investigators to the region, and their observations were 

 subsequently published. 



In January, 1884, the Council of the Royal Society 

 appointed a committee to collect and scientifically inves- 

 tigate as far as possible all data relating to the eruption. 

 The issue of their labours was a report,'' published in 

 1888. To this work we are largely indebted for the 

 materials of the present article, and also for the accompany- 

 uig illustrations, which have been copied by kind permission 

 of the Royal Society. 



In the Sunda Straits there lies a group of small volcanic 

 islands (Fig. 2). The largest of these is Krakatoa. It 

 forms part of the "basal wreck" of a large submarine 

 volcano, whose visible edges are also represented by Ver- 

 laten and Lang Islands. In the Greek Archipelago there 

 is a similar example in the islands of Thera and Therasia. 



* -i work of 500 p.vges, quarto, with maps, plates, and charts. Ihe 

 pages relating to the bibliography of the subject are also of much value. 



