348 



NATURE 



{Feb. 7, 1889 



When Mr. Lockyer first pointed out his lines of 

 coloured suns converging towards Krakatab, the data 

 were too scanty for him to recognize that the apparent 

 line through Ceylon, Ongole, and Madras, was due to a 

 widening of the main east to west stream after its first 

 circuit of the globe. As far as the motion of this stream 

 was indicated by African and South American observa- 

 tions, he was perfectly correct, though nothing was pre- 

 viously known as to its velocity or even actual existence. 

 The march of the optical phenomena which is shown in 

 Mr. Russell's maps is indeed the only direct evidence 

 we have of the fact that at 100,000 feet above the 

 earth in the immediate vicinity of the equator, the 

 air in August, and probably, as Mr. Archibald shows, 

 at other times, moves in a rapid and constant current 

 from east to west. Both in Section 111. {b) and Section 

 VII. he discusses this question in detail, and shows its 

 agreement with the theory of the general circulation of the 

 atmosphere, as well as the motions of the upper clouds 

 as far as they have been observed. 



In Section IV., Mr. Archibald investigates the height of 

 the stratum, from observations in all parts of the world 

 where the durations of the primary or secondary glow have 

 been recorded with any attempt at accuracy. Proceeding 

 on the hypothesis that the primary glow was a first reflec- 

 tion of the sun's rays by the stratum, and the secondary a 

 reflection of the primary glow, for which ample evidence 

 is adduced, he concludes that the height of the upper or 

 middle part of the stratum above the earth, diminished 

 from 121,000 feet in August 1883, to 64,000 in January 



1884, the lower limits being practically indeterminate. 

 Also, since from Dr. Riggenbach's and Mr. Clark's 

 observations, the glows continued less brilliantly and less 

 prolonged after the first few months right up to the end of 



1885, while a decided minimum in the duration, and there- 

 fore presumably the height of the reflecting layer, was 

 reached in April 1884; the important conclusion is arrived 

 at, that by that date the larger and more effectively re- 

 flecting particles had descended to a lower level, leaving 

 the finest particles suspended at nearly the same eleva- 

 tion as at first. This is further corroborated by the re- 

 markable fact that the large corona reached its maximum 

 intensity during the same rnonth. 



In Section V., Mr. Russell gives an interesting list of 

 former eruptions and accompanying atmospheric effects, 

 similar in many respects to those under discussion. 

 During 1783 and 1831, the dates of the famous eruptions 

 of Skaptar Jokull and Graham's Island, &c., and the two 

 years of perhaps the greatest eruptive activity antecedent 

 to that of Krakata'b, the after-glows and other optical 

 effects were most conspicuous, and from an examination 

 of other eruptions and sequelae, the general correspondence 

 between the two phenomena seems fairly proven. 



Section VI. is a rhumd of opinions collected by Mr. 

 Archibald, against and in favour of the volcanic origin of 

 the phenomena. Besides its value in exhibiting every 

 aspect of the question, it affords a curious illustration of the 

 narrowness and breadth of human imagination, especially 

 when dealing with phenomena whose universality and 

 minor details were at first only partially realized. 



Finally, in Section VII., Mr. Archibald gives a general 

 analysis of the connection between all the optical pheno- 

 mena and the eruptions of Krakatab both in May and 

 August, inwhich the various objections on the ground of the 

 initially rapid transmission of the appearances, insufficiency 

 of fine solid ejecta, length of time of its suspension, and the 

 occurence of apparently similar phenomena on dates pre- 

 vious to the great August eruption are discussed in turn. 

 The time of suspension of the finest dust in particular, 

 is shown — by an application of Prof. Stokes's formula,^ 



' Where <r, p, are the densities of the particle and the fluid respectively, 

 a the radius of the particle (supposed spherical), and m' the index of friction 

 r=ii, where /i is the coefficient of viscosity. Its value is either (o'ii6)'^ or 



V = ^ ( - - I )a^ for the velocity of a small particle 



descending in air, and in which viscosity is properly con- 

 sidered — to be over two years between 50,000 and 100,000 

 feet, even assuming the particles to be spherical, which is 

 the most unfavourable supposition. If, as is most prob- 

 able, they were thin plates, the time would be much 

 longer. A final summary is then given of the direct and 

 local connection between the optical phenomena and the 

 eruptions both of May and August, which the subsequent 

 discovery of the relative though minor importance of the 

 May eruption rendered necessary. 



In Part V., Mr. Whipple discusses the somewhat 

 sparse data which show that a magnetic disturbance was 

 generated by Krakatab and travelled round the world at 

 a rate varying from 760 to 900 miles per hour, but the data 

 are too uncertain to allow any definite conclusions to be 

 drawn. 



We cannot conclude without drawing attention to the 

 fact that the study of the KrakataT) sequelae has not 

 merely enlarged our conceptions of volcanic powers and 

 the continuity of atmospheric circulation, as well as yielded 

 positive information of great value to different branches 

 of science, but has opened up fresh problems in optical and 

 meteorological physics, the attack and solution of which 

 will stimulate research as well as materially advance the 

 boundaries of our present knowledge of these subjects. 



SCIENCE AND THE REPORT OF THE 

 EDUCATION COMMISSION. 



THE Final Report of the Commissioners on the 

 Elementary Education Acts, which has excited so 

 much attention of late, deserves to be noticed from a point 

 of view other than any that has yet been taken— that is, 

 the attitude of the Commission towards the teaching of 

 science in elementary schools. In a rather lengthy chapter 

 on " Manual and Technical Instruction," the ground taken 

 by the Commissioners is very clear. The teaching of 

 science in our elementary schools, they say, is yet in its 

 infancy. The importance of science teaching has been 

 so far recognized that simple object-lessons are obligatory 

 in all infant schools. This is a mode of teaching which 

 the Report recommends to be extended. Thus in agri- 

 cultural districts arrangements could be made for giving 

 practical instruction of the simplest character in the 

 principles of agriculture, the growth and food of plants, and 

 their diseases ; and similar .instruction in the elernents of 

 dairy work might be given to the girls in these districts. 

 The point here laid stress on is one that everybody who 

 knows anything of former attempts to teach science 

 to the children in Board-schools will feel the need of. 

 Science, the Commissioners emphatically say, can never 

 be taught to children out of books alone. No doubt 

 much useful and entertaining knowledge is taken from 

 text-books on science by children ; but, to use^the words of 

 the Report, the true learning of science cannot be said to 

 begin till the learners are taught to use their own senses 

 in the study, and to rest their acceptance of scientific 

 truth, even the most elementary, not on what they are 

 told, but on evidence supplied by their own observation. 

 To show the curious system of instruction pursued in our 

 schools, it is worth while mentioning that though those 

 simple object-lessons which lie, we are told, at the founda- 

 tion of scientific instruction are compulsory in infant 

 schools, yet immediately the child leaves the infant school 

 they are'discontinued until he reaches Standard V., after 

 which, if he ever gets any scientific teaching, it is out 

 of books alone. One witness considered it ridiculous 

 that English is compulsory and elementary science op- 

 tional, for, he said, English includes grammar and recita- 

 tion for boys, the latter of which, he thinks, is far less 

 likely to be useful in a manufacturing district than 



