X()Ti^:s. 



ASTRONOMY. 



BOTANY. 



Hy A. C. D. Ckommei.in. B.A.. D.Sc. F.K.A.S. 



By Professor F. Cavers, D.Sc, F.L.S. 



THi: Acu'AKii) mi:ti:ors and hallkvs 



COXfET. — In ;i leceiU number of " Knowli:i)Gi; " I referred 

 to Mr. Olivier"s observation of the Aquarids and his demon- 

 stration of their connection with Halley's Comet. The 

 Bulletin o/ flic Astroiioinicat Society of Mexico for March. 

 IQli. contains an article on the same subject by Se'ior 

 Nf. M. Marron, from which I quote the following particulars. 

 I have condensed his narrative : — 



'■ .\t half-past three on the morning of May 5th, 1910, an 

 immense ball of fire appeared to proceed from the tail of 

 Halley's Comet. It moved swiftly, lighting up the sky and 

 the landscape. 



" .-According to a telegram from Heredia on the morning of 

 May 10th, 1910, there was observed in the city of Costa Rica 

 a shower of shooting stars, fifty-three being counted in half- 

 an-hour." 



Aerolites arc also referred to on May 11th, IJth. 18th. 

 but their connection with Halley's comet is doubtful. 

 The one of May 5th appears to have been probably an 

 .Aquarid, the radiant being 338° — 2° (Denning) near Eta 

 Aquarii ; the comet at this time was in 1° + 9°, so that its 

 tail would have pissed slightly north of Eta. 



THE NEW STAR IN GEMINI.— This object was dis- 

 covered by M. Enebo at Dombaas, Norway, on the evening 

 of March 12th. when it was of the fourth magnitude. The 

 survey plates taken nightly at Harvard Observatory have enabled 

 us to trace its past history, and to say that on the evening of 

 March 10th it was fainter than the eleventh magnitude, while 

 on the following day it had reached the fifth. It took a few 

 days reaching its maximum, when it was distinctly brighter than 

 S Geminorum, and little inferior to the third magnitude; then 

 a pretty rapid decline set in, and it fell two magnitudes in two 

 days. Like Nova Persei of 1901, the fall was oscillatory; 

 thus, at Cambridge the magnitude was deduced as 5-5 on 

 March 20th, 4-7 on March 25th, 5-5 on March 26th; by the 

 end of the month it was down to the sixth. Its position for 

 1912-0 is 6" 49"" ir-75, N. 32° 15' 6"; that of Turner's Nova 

 of 1903 for 1900-0 was 6" 37"" 48"- 86, N. 30° 2' 39". The two 

 Novae are only some 3° apart ; it is rather remarkable to have 

 two outbreaks so closely adjacent within nine years. 



Herr Kaiser, of Heidelberg, has found a fifteenth-magnitude 

 star on a Wolf-Palisa plate, taken in 1909. which agrees with 

 the place of the new star within at most 2". The identity of 

 the two is highly probable but not quite certain. It will be 

 rtimenibered that Nova Lacertaeof last year was identified with 

 a fourteenth-magnitude star which had been photographed some 

 years before. The spectrum of the new star seems to have 

 been of the F5G. or Procyon, type on March 14th. On the 

 next night the usual bright and dark bands of novae had 

 appeared : these indicated velocities of some six hundred 

 kilometres per second, but the narrow absorption lines gave 

 velocities of recession of twenty kilometres per second. 

 Apropos of the variations in light of the Nova, it is appropriate 

 to refer to the new catalogue of nine thousand eight hundred 

 stars by Mr. T. W. Backhouse. It includes the whole sky 

 from pole to pole, and shows all stars visible to an ordinary 

 eye, including some of the seventh magnitude where there are 

 two stars of that magnitude within a few minutes of arc of 

 each other so that they might be seen as one sixth-magnitude 

 star. The magnitudes have been discussed and reduced to a 

 common system. A map showing magnitudes can be made of 

 any region in a few niinutes and the variations in brightness 

 of novae traced from night to night. 



NEW ;^EALAND SAND-DUNES.— In continuation of 

 his previous work on the dune areas of New Zealand. Cockayne 

 (Report, Dcpt. of Lands. S.Z.. 1911) has published a 

 detailed and fully illustrated account of his studies on the 

 sand dunes of the colony. For the botanist interested in 

 Ecology in general, this report, consisting of seventy-six 

 quarto pages, with seventy-two plates, and published at the 

 low price of Is. 9d., is of importance as being the best all-round 

 account of dune vegetation that has yet been published. 



.After dealing with the geology, topography, and general 

 environmental factors, the author gives lists of the various 

 plants of the dunes, numbering in all nearly one hundred and 

 fifty species, and proceeds to deal with practical methods for 

 the reclamation and preservation of dune areas as farmlands 

 or grazing grounds. The marram-grass (Aniniopliila 

 arcnaria) is recommended as the best of the sand-binding 

 plants. I^upins are suitable after the moving sands have been 

 fixed and protected from moving dunes, and for u.se at a later 

 stage various grasses, and so on, are described. The 

 numerous photographic illustrations show the various dune 

 plants in their habitats, as well as phases in the formation 

 and reclamation of dunes, and so on. 



Since the sand dune area of New Zealand extends over 

 about three hundred thousand acres, the question of reclama- 

 tion is one of national importance, and some action by the 

 Government of the colony is likely to result from Cockayne's 

 investigations and recommendations. 



MARSH PLANTS.— The third part of Gluck's Biologische 

 iind niorpliologische Untersiichnngen iiber Wasscr und 

 Siiiiipfgexciichsc (G. F'ischer. Jena) forms an important con- 

 tribution to the grow'ing literature of detailed biological Ecology, 

 as distinguished from that of botanical survey work. This 

 third part (" Die Uferflora '') deals with over one hundred 

 European species of marsh plants, and extends to over six 

 hundred pages, with eight fine double plates and over one 

 hundred text-figures. 



The author describes in detail the various forms of marsh 

 plants, according to w hether they develop under their optimum 

 conditions of growth (with the roots in water or saturated soil 

 and the shoots in the air) or under less favourable conditions 

 (submerged in deep water, or on the other hand stranded on a 

 dry substratum). The fresh-water flora is divided into three 

 zones: — (U submerged flora, (2) floating-leaf flora. I3> marsh 

 flora. The last named is again divided into two classes — one 

 including plants which are adapted rather for life in air, e.g.. 

 Typlia. Acoriis. Iris, Caltha, Menyantlies : and the other 

 including plants adapted more for aquatic life, under which 

 heading come the great majority of marsh plants. In the 

 first class, the plants when growing in water sutler reduction 

 of all the vegetative parts ; while the plants of the second 

 class {e.g.. Peplis. Scirpns. Littorella, Rantinciiliis lingua. 

 OenantUe fistulosa. and many others), on the contrary, show 

 increase in their vegetati\e parts when growing in water. 



Gliick pays special attention to the various forms of the 

 leaves of marsh plants. He adopts Goebel's distinction 

 between " homoblastic " types with only one form of leaf, and 

 " heteroblastic " types, in which the primary and the later 

 leaves ditTer in form. In cases where submerged leaves are 

 formed, diftering from the aerial leaves, the former are of a 

 primary type. It seems a pity that the author has not dealt 

 with the minute structure of the various leaf-forms which he 

 describes, but apart from this he brings together an enormous 

 amount of information concerning the morphology of both 



