January, 1907.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



As an illustration of one of the photographs bring- 

 ing out this point very clearly, let me put before the 

 reader this reproduction (Fig. 7). For the use of this 

 photograph I am indebted to Herr Walter, of Ham- 

 Ijurg, who secured this most interesting " multiple " 

 flash photograph on the night of May 30, 1902. The 

 motion of the camera was directed horizontally by 

 means of a special mounting operated by clockwork. 

 In this case the first flash that fell on the plate was 

 that on the left, while those towards the right occurred 

 subsequently. As will be seen, this flash was really 

 composed of five individual flashes, althoug^h to the eye 

 it appeared single. The intervals of time between the 

 individual flashes, counting from left to right, were 

 o.oj6, 0.036, 0.028. and 0.144 seconds, and the total 

 duration of the discharge was 0.244 seconds, according 

 to Herr Walter's statement. 



On examination it will be noticed that the first flash 

 was from cloud to earth, the ramifications being 

 directed downwards. In the second flash also the same 

 direction was maintained, and the branches, although 

 fewer in number, were also directed towards the earth. 

 It is worth while drawing the reader's attention to the 

 faintness of the fourth ramification from the top of the 

 first flash and to its great increase of intensity in the 

 second flash. This indicates in a striking manner not 

 only that the direction of the electric current remained 

 the same, but that even this subsidiary path already 

 made for it by the previous flash was more fully utilised 

 by the second. 



As the cloud was being discharged, so the flashes be- 

 came weaker and weaker, and the ramifications fewer, 

 until the final flash is the least intense of the five, and 

 is devoid of all ramifications. In no case have any of 

 the branches an upward direction, so that in this in- 

 stance it must be acknowledged that all the flashes 

 were from cloud to earth. 



It has been pointed out to me that it does not 

 necessarily follow that, because all the ramifications on 

 the individual images were directed towards the 

 ground, the discharge is not of an oscillatorj' nature. 

 The reason given was that the first discharge would so 

 " ionise " the atmosphere along the path it took in 

 going from earth to cloud, that the return flash to the 

 cloud would find the least resistance along the same 

 track, including even the ramifications. If this be 

 granted for a moment, an examination of the photo- 

 graph from many points of view suggests that this is 

 not the case. 



Since the flash on the left in Fig. 7 was the first to 

 occur, this discharge is necessarilv a cloud-to-earth 

 flash, because the ramifications are directed downwards. 

 .\ssuming, then, that the second flash is a discharge 

 from earth-to-cloud, should not its bottom or earth end 

 l>e stronger than its cloud end, and also stronger than 

 the earth end of the first flash? The photograph does 

 not endorse this view. 



Again, how can the strongest ramification of the 

 second flash l>e explained if the main flash be an earth- 

 to-cloud flash? It seems to me that the peculiarities 

 of this series of flashes are quite easily explained if the 

 assumption be made that the discharges are all in the 

 direction of cloud to earth. 



It is quite possible, however, that the photographs 

 already examined were " multiple " flashes, but not of 

 an oscillatory character. It would, therefore, be of 

 great interest if those who photograph lightning flashes 

 would sometimes employ a moving camera to trv and 

 obtain records of "multiple" flashes, which exhibit 

 ramifications which are alternately directed to earth 

 and to cloud. 



Having drawn attention to the occurrence of earth- 

 to-cloud lightning discharges, as exhibited in a few- 

 photographs which I have been fortunate enough to 

 secure, it is very probable that many more photographs 

 are in existence which are of a similar character. It 

 would be useful, therefore, if those who possess light- 

 ning-flash photographs would examine them critically 

 from this point of view, for it seems that such dis- 

 charges are of more common occurrence than was at 

 first believed. 



Should such a search be the means of bringing to- 

 gether a greater number of specimens of earth-to-cloud 

 flashes, a great favour would be conferred on the writer 

 of this article if he could be informed, because it is onh 

 by the close study of many of such photographs thr. 

 valid conclusions can be drawn. 



Observatory of the Ebro. 



Notes of the 1905 Eclipse. 



Many circumstances have combined to render the 

 foundation of a new Spanish obsen'atory of great inter- 

 est and importance. There is first the feelmg of not 

 unnatural surprise at such a happening in a country 

 which had for many years been regarded as non-pro- 

 gressive, and by some writers freely labelled decadent, 

 dying, effete, or some other equally uncomplimentary 

 epithet. Signs of revival are now- more numerous, 

 and a King on his own feet with an English Queen to 

 sympathise with his modern ideas bids fair to modily 

 many of the harsh criticisms passed of late years upon 

 his historic heritage. Yet the observatory is only in a 

 sense of Spanish growth. It is the latest branch of the 

 scientific activity of the powerful Society of Jesus, 

 whose labours at Kalocsa, at Hereny, at Stonyhurst, at 

 Georgetown, D.C., at Havana, at Manila, and many 

 other posts are landmarks in the domains of astronomy 

 and cosmical physics. 



In succession to the late Father Juan, Father Cirera, 

 in charge of the magnetic department at the Philippine 

 Observatory, pursued the investigation of the periodic 

 variations of the magnetic elements until circumstances, 

 possibly not unconnected with the change of ownership 

 of those islands, which did not, however, involve any 

 immediate stoppage of the work, recalled him to Spain. 

 Loth to give up the investigation to which for more 

 than ten years his energies had been applied. Father 

 Cirera obtained the sanction of the Provincial Head of 

 his Order to the establishment of an observatory in 

 .\ragon, at which that work might be continued. 



The question of funds had, of course, to be con- 

 sidered, in addition to the choice of situation and equip- 

 ment, and several years were devoted to preparation. 

 Most of the best known Furopean observatories were 

 visited in turn, and much time spent in picking up new 

 ideas at the Paris Exposition; in fact, a whole year 

 was spent in Paris, and ten months at Stonyhurst, 

 shorter visits being paid to Kew and Cireenwich, and 

 at the beginning of igoj a site was chosen which 

 possessed the strong recommendation, among others, 

 that it lay within the region of totality for the eclipse 

 of August 30, 1905, which incidentally fixed a date 

 before which the installation sln)uld be, if possible, com- 

 pleted. 



Father Cirera had been struck with the poverty in 

 modern electrical and seismological equipment of the 

 observatories of England and France, and prtxeeded 

 to those of Belgium, IJermany, .\ustria-Hungary, and 



