April 13, 1899] 



NA TURE 



561 



focus is employed, the multiple images become blurred 

 and indistinct. The appearance ultimately presented is 

 that of a band of light crossed by a very large number — 

 probably 400 or 500— of hazy dark lines at right angles 

 to its length. These might be produced by some 

 structure in or near the crystalline lens or the cornea 

 composed of elements measuring about tjoW '''^^ '" 

 length or breadth. 



I do not know of any simple structure sufficiently 

 coarse-grained to account for the images of which 

 25, or thereabouts, occur in a row. The mesh of a net- 

 work which would explain these should be about 

 j-Jy inch (o'2 mm.) in length, and nothing of the kind 

 IS, I believe, to be found in the eye. Probably, however, 

 the efiect is a composite one, like that of the two pieces 

 of gauze used in photographing the lamp. If light 

 passed through two superposed nets having fine meshes, 

 dark bands would generally be produced, which would 

 take the form of a network of a coarser mesh than those 

 of the nets themselves — possibly much coarser, as would 

 be the case if the two nets were nearly alike in structure. 

 Shelkord Bidwell. 



NEW STAR IN SAGITTARIUS. 

 A CIRCULAR (No. 42) from the Harvard College 

 ■^^ Observatory, informs us of the detection of a new 

 star in the constellation Sagittarius by Mrs. Fleming, 

 during the e.xamination of the Draper Memorial photo- 

 graphs. The date of appearance is not yet definitely 

 determined, but was either in the latter part of the year 

 1897 or the early part of 1898. The approximate position 

 for 1900, as found from the Durchmusterung Chart of the 

 region, is 



R.A. = i8h. 56m. 1 2 -25. Decl. = - if 18' 16". 



The star was too faint to be photographed on eighty- 

 seven plates exposed during the period 1888 Septem- 

 ber 5 to 1897 October 23, even though the last of the 

 plates taken in 1897 showed stars down to the 15th mag- 

 nitude, the instrument being the 24-inch Bruce telescope 

 at Arequipa. The Nova first appears on eight plates 

 taken in March and April of last year — four at Arequipa 

 with the 8-inch Bache telescope and four at Cam- 

 bridge, Mass., with the 8-inch Draper telescope, both of 

 these instruments being provided with prisms outside the 

 objectives. It may be added that both the lenses are 

 doublets. The estimated magnitudes are from com- 

 parisons with adjacent stars, and are to be regarded as 

 approximate, as the star was away from the centre of 

 plate in several cases. On March 8, 1898, the magnitude 

 is given as 47 ; while on April 29, 1898, it is 8'2. 



The Nova has of course been detected from the 

 peculiarity of its spectrum, which consists chiefly of 

 bright lines. The best photograph was obtained on 

 April 19, 1898, with an exposure of sixty minutes, the 

 magnitude of the star then being 8'2. The spectrum, 3 

 mm. in length, shows the lines H.s, Hy, H^, He, Hf, H,,, 

 and probably H9, due to hydrogen, bright. A broad 

 band at A 4643 is also bright, and narrow bright lines 

 are present at XX 4029, 4179, 4238, 4276, 4459, and 4536, 

 these latter appearing to be identical with lines at corre- 

 sponding positions in the spectrum of Nova -Aurigre. 

 The strongest dark line is at X 4060. As in the Nova; 

 Persei, Aurigie, Norma", and Corin;e, the line He is 

 bright ; while in variables of long period this line is 

 always dark., being possibly obscured by the neighbour- 

 ing broad calcium line H. This difference may serve to 

 distinguish between Nov:c and variables. The accom- 

 panying dark lines on the more refrangible edges of the 

 bright bands of Nova? Aurig;c, Norma;, and Corina; are 

 not visible in the spectrum of Nova Sagittarii. The 

 calcium line K is also invisible. In the photograph ob- 



NO. 1537, VOL. 59] 



tained two days later— 1898 April 21— -certain marked 

 differences are noted. The broad dark line X 4060 has 

 disappeared, and a narrow bright line appears at X 5005, 

 possibly identical with the chief nebula line at X 5007. 

 The hydrogen lines appear to be narrower and more 

 intense. 



Plates exposed at Arequipa on October 7 and 8, 1898, 

 but not yet examined, will furnish important information 

 as to the rate of diminution of the light of the Nova. 

 On the morning of March 13 of this year. Prof O. C. 

 Wendell examined the star with the photometer at 

 Cambridge, and found that its magnitude was then 1 1"37. 

 \'isual examination showed its light to be nearly mono 

 chromatic, with a faint continuous spectrum, in this re- 

 spect resembling other Nov;e that have preceded it, in 

 haying changed to a gaseous nebula. This change had 

 evidently begun at the time of the photograph taken on 

 1898 April 21, showing the line X 5005. 



It is interesting to note that of the six new stars which 

 have been discovered since 1885, five have been found 

 by Mrs. Fleming during her detailed examinations of 

 the Henry Draper Memorial photographs of stellar 

 spectra. 



During the last four hundred years fifteen stars have 

 appeared which may be regarded as Novae, and, in 

 general, have been found in the vicinity of the central line 

 of the Milky Way, their average galactic latitude being 

 about ii"'2. Nova Andromedse and Nova Centauri 

 showed no bright lines in their spectra, and, if these be 

 excepted, the average galactic latitude of the remaining 

 thirteen is 9°'o. Of these Nova Corona; is the only new 

 star with bright lines in its spectrum which has appeared 

 far from the central line of the galaxy, its latitude being 

 46°'8. If this also be excepted, the average galactic lati- 

 tude of the other twelve is reduced to 5" '8. It is thus to- 

 be inferred that there is some association between the 

 galaxy and the new stars whose spectra contain bright 

 lines, as the probability that such a distribution is due to- 

 accident is extremely small. 



FRANZ RITTER VON HAUER. 

 A DISTINGUISHED Austrian geologist has passed 

 ■^^ away in the person of Dr. Franz Ritter von Hauer, 

 the Intendant of the Royal Imperial Natural History 

 Museum of Vienna. Von Hauer was born in Vienna on 

 January 30, 1822, and received his education partly in 

 that city, and subsequently at the mining academy of 

 Schemnitz. In 1846 he became assistant to Wilhelm von 

 Haidinger, who was then councillor of mines and lecturer 

 on mineralogy in Vienna. Later on, in 1849, when Von. 

 Haidinger was appointed director of the then newly- 

 established Imperial Geological Institute, Von Hauer 

 was engaged as geologist, and he took a leading part in 

 the work of the survey, succeeding to the post of director 

 on the retirement of his chief in 1866. 



Among his special geological works, those on the 

 Cephalopoda of the Triassic and Jurassic formations of 

 eastern Alpine regions are the most numerous and im- 

 portant ; but he contributed other papers and works on 

 mineralogy and applied geology. 



His most important general work was that of the 

 geological map of the Austro-Hungarian monarchy, 

 which was issued in twelve sheets, 1867-71, and of which 

 a fourth edition, including Bosnia and Montenegro, was 

 published in 1884. His explanatory pamphlets relating 

 to this great map have been described as " models of 

 concise description," while his general manual of Austrian 

 geology, published in 1875, "is the best guide we have 

 to some of the most interesting parts of Central and 

 Eastern Europe." The remarks quoted were made by 

 Mr. R. Etheridge in 1882, when as president of the 

 Geological Society he forwarded to Von Hauer the 



