394 



NA TURE 



[Fkbruary 26, 1903 



July 20, iS4S, and describes how parts of the coast 

 suddenly appeared, standing, so to speak, in the middle 

 of the channel. 



Coming to recent times, we have a description in the 

 Zag&ra for 187 1 by an anonymous writer. A white 

 streak of mist passing across the Sicilian coast melted 

 like a transparent veil, revealing arches, towers and 

 colonnades floating on the sea, houses, and woods of many 

 colours. 



Not less explicit is Prof. Filippo Capri, who described 

 in the Zagd.ro. the Fata Morgana of June 20, 1874, which 

 occurred between 8 and 9 a.m. The weather was so hot 

 as to ruin the crop of bergamot fruit, and the pheno- 

 menon, as on other occasions, was preceded by a white 

 mist. Buildings were seen to become elongated, while 

 the shores, with their villas and trees, became detached 

 like islands and then disappeared. In answer to the 

 invitation for an explanation, Dr. Diego Corsa repeated 

 Minasi's erroneous opinions, but this point of view was 

 attacked by Prof. Canale, who, however, did not venture 

 to formulate a theory of his own, having only seen the 

 phenomenon once. 



Prof. Boccara speaks from personal knowledge of three 

 displays of the Fata Morgana under its three different 



vertical dark stripes was attributed to the wall of the 

 citadel at Messina, and it appeared to blot out the 

 houses of the town. 



Prof. Boccara attributes all these phenomena to 

 variations in atmospheric density, which produce refrac- 

 tion effects. It may be suggested to the mathematician 

 that consideration of the principle of least time for the 

 path of a light ray affords an easier way of thinking of 

 the conditions necessary for the phenomenon than is given 

 by the sine law of refraction. The term Fata Morgana 

 is used by the author exclusively in connection with 

 apparitions in which the images are erect. When 

 inversion takes place, so that the phenomena are due to 

 reflection, the effect is a mirage, a phenomenon also seen 

 not unfrequently on the Sicilian coast. 



The neighbourhood of Reggio is peculiarly adapted 

 to the display of the Fata Morgana both by its topo- 

 graphical peculiarities and by the meteorological con- 

 ditions not unfrequently existing there These conditions 

 are, a morning hour, hot weather, extreme clearness of 

 the air, combined, however, with a thin veil of mist over 

 the Sicilian coast, and a calm air or slight wind from the 

 north, as conditions for the marine morgana. For the 

 aerial morgana, the best time of day is from 10 a.m. 

 to 1 p.m., with a stratum of light cloud on the coast of 

 Sicily, sea calm or nearly so, a high temperature and 



Fig. 1. — Aerial Morgana of June 27, 1900. 

 Fig. 2 shows the white mist just before the commencement of the 

 phenomenon. 



forms — namely, an aerial morgana on June 27, 1900, wit- 

 nessed by himself. Captain Vincenzo Ponzi, of Chiaggia, 

 and Prof. Enrico Puccini ; a marine morgana on July 2, 

 1901, also seen by Prof. Puccini ; and a multiple morgana 

 on March 26, 1902. The first is well shown by the author's 

 sketch in Fig. I, Fig. 2 giving an idea of the white mist 

 seen just before the occurrence of the phenomenon, and 

 which disappeared when the occurrence took place. In 

 it, the houses on the Italian coast at Gallico and the 

 point of Catona are seen to be considerably elongated in 

 a vertical direction, and, so to speak, projected on the 

 Sicilian coast beyond, the straits appearing to be con- 

 verted into a gulf. In the marine morgana of 1901, a 

 cloud again formed just previously, and the appearance 

 was presented of arches standing below the sea line in 

 an upright position, their bases having no visible foun- 

 dation. These arches corresponded to some railway 

 arches above the cemetery of Messina, but were more 

 brilliant and larger than the real arches. Of the third or 

 multiple morgana, Prof. Boccara has given an illustration 

 in Fig. 3, which, however, represents simultaneously 

 various phases of the phenomena which were in reality 

 seen in succession. Thus the three houses at the left 

 were not all visible at the same instant ; when one 

 appeared, the other disappeared. The white band with 



NO. I739, VOL. 67] 



Fig. 3. — Multiple Morgana of March : 



wind as before. A multiple morgana is, of course, of 

 much rarer occurrence than the simple form, and the 

 one seen in March, 1902, was less marked than one 

 observed about twenty years previously by Prof. Scerbo 

 and Signor Aloi, of which a sketch is reproduced in Dr. 

 Boccara's paper. G. H. B. 



INDIAN RAINFALL. 



EVERYONE acquainted with the rainfall statistics 

 of India is familiar with the appendix to the 

 third volume of the Indian Meteorological Memoirs, 

 which was published in the year 188S, when Mr. H. T. 

 Blanford was Meteorological Reporter to the Indian 

 Government. This appendix contained the monthly 

 and yearly rainfalls for each station which possessed 

 a rain-gauge, and the period over which the observa- 

 tions extended was in some cases, such as Bombay, 

 Madras and Calcutta, very long, the last year in which 

 the observations from all stations were included being 

 that of 1886. 



Since that epoch many years have passed, and the 

 time had evidently arrived for this volume to be 

 brought up to date and the whole mass of useful 

 rainfall data collected together under one cover. We 

 are glad to say that this large piece of work has now 

 been completed and published (1902), and forms the 

 fourteenth volume of the Memoirs. 



