300 



NA TURE 



[January 24, 1895 



he finds it to be 315 ± '19 kilometres per second, a value which 

 agrees very closely with some recent determinations. 



The light of the Blue Grotto of Capri, as well as that of the 

 so-called red and green grottoes (^otlo rosso and ^otto vtrle) 

 has been spectroscopically tested by Dr. 11. W. Vogel, and is 

 described in the current number of IVitJeinann's Annalen. 

 The most striking fact abnut the Blue Grotto was the occur- 

 rence of an absorption band between the Fraunhofer lines C 

 and E of the solar spectrum, which does not occur in ordinary 

 water. Inaddiiion to this, the red and the orange were fxtin- 

 guished as far as the D line. The same spsctrum was exhibited 

 by the water in front of the grotto. The "green grotto " is a 

 rocky tunnel filled with bluish-green sea-water. The rocky 

 walls show green reflections in the interior, produced by the 

 impact of the bluish light from the water upon the yellow stones. 

 But the absorption band noted in the Blue Grotto is here en- 

 tirely absent. From the top of the cliffs, patches of azure-blue 

 water could be seen surrounded by green. They all showed the 

 absorption band, and retained their position permanently, so that 

 they are probably due to some local cause. The " red grotto " 

 does not show a trace of red liijht. 



Attention was recently drawn in our columns to an interest- 

 ing observation made by Dr. Ostroumoff, of Sebastopol, on the 

 power possessed by the Copepod Ponlellina mediurranea, of 

 jumping in the air upon the surface film of water. It appears 

 from several further communications that this peculiar habit is 

 also possessed by several other Copepods, viz. Pontellaatlantica 

 (M. Edw.), according to Dahl(f-Vry4. deiitsch. Zool. Gesclt. 1S94, 

 p. 64), and Pontilla semrifer {^taiy), according to an observa- 

 tion made by Captain Hendorff, who stales that he several times 

 saw this Copepod leap qui'e a foot high from the water in which 

 it was contained. Herr Mrazek, in recording Captain HendorfTs 

 observations (Zool. Anz. No. 415, p. 5), also men'ions the 

 additional case of a Schizopod having the same habits. This 

 phenomenon, however, can be easily observed in the case of 

 British Schizopods, and appears to be the result of abnormal 

 conditions rither than a natural habit. Herr Mr.-izek does not 

 support Dr. Ostroumo ff in his view of the connection between 

 this habit and the process of exuviation ; he regards the move- 

 ments in question a^ either purposeless and sportive, or for the 

 sake of effecting escape from enemies. The latter view 

 certainly receives support from the somewhat analogous case of 

 the flying fish. 



We have received an elaborate paper read before the Con- 

 gress of Scandinavian Naturalists at Copenhagen, by Dr. 

 Ernst Abery, on the transmission of yellow fever. Much 

 uncertainty and difference of opinion exist as to the means by 

 which thi« disease is distributed, some authorities asserting that 

 it has a purely local malarial origin, and cannot be imported 

 into a place ; whilst others are equally convinced that it can be 

 imported, but is not transmissible directly from one individual 

 to another. Dr. Abery, whj has made a special study ol the 

 subject, has gathered together the principal facts about the 

 dissemination of yellow fever, which are admitted by various 

 authorities, and seek* to connect them together and explain 

 them by a theory of his own. He accepts for this purpose the 

 presence of a particular microbe specific to yellow fever, and 

 regards it as capable of existing in different forms, such as spores 

 and rodlets, and endowed with correspondingly different charac- 

 ters and degrees of virulence. By means of this theory, Dr. 

 Abery explains many otherwise puzzling phenomena, and has 

 produced an excellent working hypothesis. Unfurtuoalely, 

 however, it must remain only a hypothesis, lor so far no microbe 

 ipecific to yellow fever his been discovered and accepted ; but 

 possibly the author inteods attacking this aspect of the question 

 next. 



NO. 13 I 7. VOL. 51I 



The new volume of Memoirs (Zapiski) of the Caucasian 

 Geographical Society (vol. xvi.) is again one of exceptional in- 

 to est. It contains, first, a series of botanical papers on the 

 rtnra of Northern Caucasia, by I. Akinfieff, together with an 

 account of a journey of the same author in Ossetia and Svanetia ; 

 three papers, by N. M. Alboff, on the vegetation of Western 

 Transcaucasia, on new species found in Abkhasia, and on the 

 Abkhasian ferns ; and an abridged translation of several papers, 

 by Dr. E. Dieck, on the flora of Western Transcaucasia ; the 

 series thus making a very valu.ible addition to our present 

 knowledge of the flora of Caucasus. And next, the same 

 volume contains a series of papers devoted to the still imper- 

 fectly known parts of the central section of the Main Caucasus 

 ridge. M. N. Zhukoff contributes a paper on the glaciers of 

 North-east Svanetia, with a new and very interesting map 

 (i 3 miles to the inch) of a wide glacier region ; A. V. Pastuk- 

 lioff describes his ascensions of the Shah dagh and the Ararat, 

 as well as his visits to some of the high-level villaL;es, of which 

 Kurush, situated at a height of 8175 feet, is the highest in 

 Caucasia — the paper being accompanied by small maps and 

 photographs of the Kichendagh, the Nesen-dagh, and the 

 Kurush village ; M. and Mme. Rossikoff contribute two papers 

 on the glaciers and Alpine lakes of the Central Caucasus 

 main chain, giving exact measurements of the speed of 

 motion of several glaciers ; and another Alpinist, N. Dinnik, 

 gives a description of Mount Oshten and the surrounding parts 

 of the province of Kuban, which is full of very interesting 

 gengraphical and botanical data. And, finally, two papers, by 

 MM. Shalikoff and Andronikoff, are geographical and statistical 

 descriptions of two districts of the government of Tiflls — Ksan 

 and Uraveli. An index of all the papers contained in the 

 hitherto published volumes of both the .I/f/ai'/ri (Zapiski) and 

 the Bulletin (Izvestia) of the Caucasian Geographical Society, 

 is also a most welcome feature of the present volume. 



A SECOND edition of Dr. G. V. Poore's instructive " Essays 

 on Rural Hygiene" has been published by Messrs. Longmans, 

 Green, and Co. The new edition includes more than fifty 

 additional pages. 



The Rose Polytechnic Institute, Terre Haute, Indiana, has 

 published a bulletin on "Physical Units," by Prof. Thomas 

 Gray. The bulletin comprises a concise and admirable col- 

 lection of definitions of fundamental and derived units. 



No. 2 of the Bolanisclies Cenlralblalt for 1S95 contains an 

 exhaustive bibliography of the colouring matters of plant?, by 

 Dr. Hermann Ritter Schroiter-Kristelli, together with some 

 new observations on the occurrence of carotin. 



A WORK entitled " Molecules and the Molecular Theory of 

 Matter," by .\. D. Risteen, will be published in February by 

 Messrs. Ginn and Co. The work is intended to be a pri|iular 

 exposition of the molecular theory of matter as it is held by 

 the leading physicists of to-day. The subject is treated from 

 a physical standpoint. 



When a book twenty years of age blossoms into a second 

 edition, it is hardly necessary to say that the original must 

 have undergone a thorough revision. This is the case with 

 Prof. Alfred Newton's little " Zoology," published in 1S74, 

 among a series of manuals of elementary science, by the 

 Society for Promoting Christian Knowledge. The new 

 edition takes in much of the zoological work done during the 

 past two decades, thus rendering it one ol the cheapest, 

 handiest, and best broad introductions to the study of zoology 



The publication is announced of the first number of a 

 Pliy(ollieca/l»reali-ameri((tna,\hy Messrs. F. S. Collins and Isaac 

 Holdcn and Dr. W. A. Sctchcll. The work will include all 

 families of Alga:, both freshwater and marine (except, for the 



