October 19, 1888.] 



SCIENCE. 



191 



portant studies of the American Republic by foreign hands. It ex- 

 amines very carefully our whole governmental structure, Federal and 

 State, and the social economy and political foundations on which 



the edifice rests." Tlid Kiiuicrgarten, Chicago, is fulfilling its 



claims to give to mothers of young children methods of amusement 

 combined with instruction. 'Nursery Occupations' and 'Typical 

 Lessons,' in the October issue, yive practical hints that alone would 

 pay the price of subscription. The English Illustrated Maga- 

 zine, published by Macmillan & Co.. is to be enlarged to seventy 



pages, the price remaining the same (15 cents). Edward Meeks, 



Philadelphia, has in preparation a second edition of Roper's ' Hand- 

 book of Modern Steam Fire-Engines.' ' Gardner's School Build- 

 ings ' (E. L. Kellogg & Co., 25 Clinton Place, New York) will be 

 out this week ; also (by same publishers) No. 1 1 of Teacher's Man- 

 ual Series, entitled 'The Argument for Manual Training,' by Dr. 



Nicholas Murray Butler. In the Overland Monthly for October 



is a paper on fog and fog-signals on the coast, by Mr. F. L. Clarke, 

 who developed some facts of importance to seafarers on ' areas of 

 inaudibility ' of signals. The Nl~w York JVorld hus in prepara- 

 tion ' The World Almanac for 1889.' 



LETTERS TO THE EDITOR. 

 Kiessling's Twilight Phenomena.' 



Simultaneously with the publication of the ' Royal Society's 

 Report upon the Krakatoa Disaster and its Results,' comes the 

 most important German contribution to that section of the subject 

 treating of the abnormal glows, — a subject which occupies two- 

 thirds of the ' Royal Society Report,' of nearly five hundred pages. 

 The bulk of the contained matter is nearly equal in the two books ; 

 but it is drawn from such diverse sources, and the views pro- 

 pounded in the theoretical parts are so different, that only a small 

 proportion of the whole appears in duplicate. The beautiful col- 

 ored plates in each curiously support the main theory of the book, 

 their fidelity to nature indicating the probability that the diffractive 

 effects advocated by Professor Kiessling and the reflection upheld 

 by the ' Royal Society Report,' each have a share in the final result. 



The historical introduction deals with the study of twilight phe- 

 nomena : Von Bezold's admirable summary (the work is dedi- 

 cated to the distinguished director of the Berlin Royal Meteorologi- 

 cal Institute) is given in detail. The work is then divided into two 

 parts, four sections treating mainly of observations, and two of 

 e.\periment and conclusions. 



Section I. gives a detailed list of glows in forty-four years, noting 

 any coincidences with earthquakes and eruptions. The three opening 

 dates are 9S9. 1 11 7, and 1554. There are at least seven earthquake 

 coincidences, the associated glows being strictly local. The ' Royal 

 Society Report's ' list is of the one hundred and fifty-five chief vol- 

 canic eruptions since 1500, and glows (thirty-one in all), in parallel 

 columns. Thirty of the latter coincide with eruption years, which 

 number is increased nearly one-half by Kiessling's tables. Most 

 worthy of notice is the remarkable completeness of detail concern- 

 ing the European glows after the eruption of Graham's Island, near 

 Sicily, which was also submarine. 



Section II. largely occupies the ground of the ' Royal Society 

 Report,' Part IV. Sect. II., both being lists of special appearances 

 since Aug. 26, 1888, approaching nine hundred each in number. 

 The former, however, continue on to the close in 1886. while the 

 latter are chiefly confined to 1883. The immense amount of valu- 

 able records obtained from the ships' logs of the two countries 

 is very striking. It will be a great pity if similar work is not per- 

 formed in connection with the merchant marine of North America. 

 The North American land-returns have been copiously drawn upon, 

 especially by Professor Kiessling, thanks to the Monthly Weather 

 Review ; but here, again, there must be a rich store of private rec- 

 ords awaiting collation. 



Four excellent maps, for Aug. 26 to Sept. 30, for October, No- 

 vember, and December, 1883, contain localities, with dales, for the 

 glows, by which their progress can be easily traced. With the 

 same object in view, the records in the list, up to the close of No- 



^ Untcrsuchungcn iiber D.Hm!nerungserscheinungen, zur Erklarung der nach dcm 

 Krakacau-ausbrucli beobactitetcn atmospharisctioptischen Storuiig, von J. Kiessling. 

 Hamburg and Leipzig, Leopold Voss, 1888. 



vember, are arranged in four parallel columns, according to longi- 

 tude. 



Professor Kiessling throughout treats the bright ' glory ' round 

 the sun, known as ' Bishop's ring,' as the most important phase of 

 the glows. Section III. describes its appearance, spread, and 

 changes, the explanation forming an important portion of the sec- 

 ond part. His already published and generally accepted explana- 

 tion of it by diffraction is there supported by a most interesting se- 

 ries of experiments. The equally unique appearance of the counter- 

 bow, at the point opposite the sun directly after sunset, he thinks 

 is to be regarded as of similar origin. This was noted in Europe 

 almost simultaneously with the glows : on Nov. 27, 1883, and Dec. 

 15 and 20, at Sunderland, by Mr. T. W. Backhouse; Dec. 22, 1883 

 (not 1884 as misprinted in ' Warner's Prize Essays,' p. 40;, by L. 

 Richardson at Newcastle : on Dec. 29 to Jan. 3, by Herr Jesse, 

 Steglitz ; and on Jan. 12, 1884, by the writer. Measurements by 

 the first and last prove identical with those of Bishop's ring. As 

 most people chiefly regard the rising or setting sun, the anti-solar 

 phases escape observation. Hence all observations of the counter- 

 bow would specially repay collation. 



In Section IV. Professor Kiessling, dealing with the outspread of 

 the glows, shows that the originating cloud-haze must have consisted 

 at first of distinct streams, the probable courses of some of which he 

 indicates. The velocities of outflow he fixes at between sixty-seven 

 and eighty-nine miles per hour, as against seventy to eighty-four, 

 the extreme values deduced in the ' Royal Society Report.' Both 

 conclude that the height, for Europe, was about twelve miles. 



The artificial formation by diffraction in dust, condensed vapors, 

 etc., forms the subject of Section V., which opens the second part, 

 and his simple but effective experiments deserve wide repetition 

 and development. Incidentally capital illustrations are given of 

 cloud-formation. His previous publications upon this subject are 

 considerably expanded, and fresh applications made. As already 

 stated, they form the main basis of his contention for diffraction 

 as the paramount cause of all the phases of the glows, admit- 

 ting, however, reflection as a subsidiary agent. His method of 

 treating the glow-colors concentric to the sun apart from the 

 glow-colors parallel to the horizon, upon which, during the tsvilight, 

 the former are superposed, greatly simplifies their elucidation. 

 Probably his arguments as regards the former class will be re- 

 garded as the more convincing, especially as diffraction so obvi- 

 ously explains Bishop's ring. As to the horizontal layers, no doubt 

 diffraction plays a considerable part, but as certainly Messrs. Rus- 

 sell and Archibald, in the ' Royal Society Report,' rightly uphold 

 reflection as the main factor. In this they are supported by Profes- 

 sor Ricco. Of the various objections brought forward by the latter, 

 two may be noted. Professor Kiessling accepts the interposition of 

 clouds or mountain-peaks as the cause of the dark bars often divid- 

 ing the first glow; but this could hardly apply if the main light is 

 due to diffraction. Again: with the others he considers the second 

 glow to be a reflection by the haze-layer of the first. Such a sur- 

 face, then, would surely reflect direct sunlight as well. 



To some of the objections, however, the present work indicates 

 Professor Kiessling's probable reply ; as, the possibility of the dust- 

 haze so quickly assuming the homogeneity required by his theory', 

 and the occasional appearance of day and twilight glows independ- 

 ently. We may also notice that he ascribes the haze-cloud 

 chiefly to condensation products, while the ' Royal Society Report "^ 

 favors mirror-like surfaces from microscopic pumiceous bubbles. — 

 conditions in each case in harmony with the adopted theory. The 

 discussion of tropical sunsets at Loango and in South America pro- 

 vides Professor Kiessling with several strong points, for in these 

 instances he is able to show a remarkable agreement between obser- 

 vation and experiment. The excellent colored sketches by Dr. 

 Pechnel-Loesche are here a material assistance. 



The general arrangement of this valuable work is well adapted 

 for reference. Only one misprint of any moment has been noted : 

 on p. 55. §44, "iio°0" should apparently be " iio^O," or the 

 " Middle Dog " Lighthouse lies some distance inland in China. 

 The printing is most exquisitely clear, which is no small boon, for 

 the title is not the only word, which, to eyes accustomed chiefly to 

 English words, are almost appallingly long. 



J. Edmu.vd Clark.. 



