44 3 



NA TURE 



[March 8, 1906 



A number of papers on aerial navigation have appeared 

 comparatively recently. Of Captain Ferber's work on 

 stability of aeroplanes mention has been already made 

 (p. 350), and it may be sufficient to add that in this par- 

 ticular connection, contrary to the old adage, " an ounce 

 of theory is worth a pound of practice." But the same 

 writer has since sent us a reprint of papers in the Revue 

 d'Artillerie for August last, now published by Berger- 

 Levrault, of Paris, under the title " Pas a Pas, Saut a 

 Saut, Vol a Vol," which, to emulate the author's style, con- 

 stitutes a comprehensive vol au vent of experimental 

 gliding up to date, illustrated by many figures. Turning 

 a little further back to the Revue scientifique (5, iii., 

 24, 25), we find an interesting discussion by M. Bazin of 

 the source of energy in sailing flight of birds. The theory 

 is essentially identical with that brought into prominence 

 by Langley's work, in which variations in wind-velocity 

 account for the phenomenon ; but the author has also 

 shown how models can be constructed in which this ex- 

 planation is illustrated by the motion of a marble rolling 

 on a movable kind of switchback. More recently, in the 

 Revue ginirale des Sciences (xvi., 21), M. M. L^ger 

 details his attempts at obtaining the necessary lifting 

 force in a machine of the " plus lourd " type by a com- 

 bination of " helicopters " (vertical screws) and aero- 

 planes ; his experiments have been carried out with the 

 assistance of the Prince of Monaco. A little further back 

 in the same series Lieut. -Colonel G. Espitallier discusses the 

 materials and construction of balloons. Prof. S. P. Langley's 

 work is described in a pamphlet, reprinted from the Smith- 

 sonian report by the Washington Government. A paper has 

 also reached us from Madrid detailing the formation of 

 a Royal Ae'reo-Club of Spain. The current numbers of 

 the Aeronautical journal contain too much matter to be 

 summarised here. Attention should, however, be directed 

 to the flying model competition organised by the Aero- 

 nautical Society for July of this year. 



A copy of the twenty-sixth volume of the Proceedings ol 

 the Dorset Natural History and Antiquarian Field Club 

 has been received. The volume has been edited by Mr. 

 W. Miles Barnes. It contains the presidential address of 

 Mr. Nelson M. Richardson, and, in addition to other con- 

 tribufions, papers by the Rev. O. Pickard-Cambridge, 

 F.R.S., on new and rare British Arachnida ; the Rev. E. F. 

 Linton, on Dorset plants ; Mr. H. Stillwell, on the returns 

 of rainfall in Dorset ; the Rev. H. S. Solly, on the land- 

 slip at Lyme Regis ; Mr. W. B. Barrett, on the flora of 

 the Chesil Bank and the Fleet ; and the president, on first 

 appearances in 1904 of birds, insects, and first flowering 

 plants in Dorset. 



OUR ASTRONOMICAL COLUMN. 



Discovery of a New Comet, 19066. — A telegram from 

 the Kiel Centralstelle announces the discovery of a new 

 comet by Herr Kopff at the Konigstuhl Observatory on 

 March 3. 



At 14b. 52 8m. (Konigstuhl M.T.) on the day of discovery 

 the position of the comet was 



R.A. = nh. 35m. 56s., dec. = + i° 40', 

 and the following values were determined for the daily 

 movement :— in R.A. -7' (-28s.), in dec. +4'. 



\ econd telegram from Kiel announces that Dr. Valen- 

 tiner, observing at the Konigstuhl Observatory, Heidel- 

 berg, on March 4, recorded the position of this object as 



R.A. = nh. 35m. 35 -8s., dec. + i° 40' 37" 

 at ioh. 13.4m. (Konigstuhl M.T.). 



Thus it will be seen that the comet is in the southern 

 part of the constellation Leo, and was about half-way 

 NO. 1897, VOL. J!)] 



between v Leonis and /3 Virginis when discovered. It is 

 travelling very slowly in a W.N.W. direction, and is on 

 the meridian about midnight. No intimation of its magni- 

 tude has, as yet, been received. 



The Ring Nebula in Lyra. — In 1902 Dr. Newkirk 

 showed, in his inaugural dissertation for the doctor's degree 

 at Munich, that the central star in the annular nebula in 

 Lyra had a proper motion, and, from the value he obtained 

 for this movement, he deduced the parallax of the nebula, 

 finding it to be o"-io. 



As this was the first nebula for which any proper motion 

 and parallax had been deduced, the verification of Dr. 

 Newkirk's results became a matter of great importance, and 

 therefore Prof. E. E. Barnard has made several measure- 

 ments, photographic and visual, with the 40-inch refractor 

 at Yerkes Observatory. 



The results obtained do not verify those of Dr. Newkirk. 

 According to the latter the total displacement of the nucleus 

 during the five years which elapsed between Prof. Barnard's 

 observations in 189S-9 and those of 1903-4 would have 

 amounted to o"-90, an easily measurable quantity, but no 

 displacement at all could be detected. 



As Dr. Newkirk's parallax for the central star depended 

 upon his value for the proper motion, it must now, accord- 

 ing to Prof. Barnard's results, be rejected as fallacious. 



The latter observer concludes from his observations that 

 everything in the immediate region of this nebula seems to 

 have the usual fixity of the ordinary small stars (Monthly 

 Notices R.A.S., vol. lxvi., No. 3). 



A Cluster of Nebulae in Perseus. — In No. 4069 of the 

 Astronomische Nachrichten Dr. Max Wolf describes his 

 discovery of a number of small nebulae in the regions about 

 /3 and Nova Persei. These objects were seen, and their 

 positions measured, on photographs obtained with the Bruce 

 telescope, and they mostly lie in two bands, for which Prof. 

 Wolf gives the positions. 



The nebulas are especially dense where these two bands 

 coalesce, a region of 12' (of arc) square containing 148 of 

 them. Their forms are generally recorded as " round, with 

 central condensation," and " form of Andromeda nebula." 



Twenty-five New Variable Stars. — Circular No. 107 of 

 the Harvard College Observatory contains the positions and 

 magnitudes of twenty-five variable stars recently discovered 

 by Miss Leavitt from the examination of six plates taken 1 

 with the 24-inch Bruce telescope. 



The plates are of fine quality, and probably show 

 altogether some 200,000 star images. The twenty-five 

 variables contained in the list lie in the constellations Orion, 

 Virgo, and Cygnus, and two of them in the last named 

 constellation have magnitude ranges of 35 and 3-0 re- 

 spectively. 



The Glow surrounding the Lunar Crater Linne. — 

 Some interesting results of observations of Linnet are pub- 

 lished by Prof. E. E. Barnard in No. 4075 of the Astrono- 

 mische Nachrichten. 



The glow surrounding the crater was measured, on 

 various dates between December, 1902, and November, 

 1904, with a micrometer attached to the 40-inch refractor 

 at Yerkes, and Prof. Barnard concludes that its diameter 

 does vary with the moon's age. The following table re- 

 presents the curve, obtained from the observational results, 

 for the varying diameters : — 



Mood's age Diam. of glow Moon's age Diam. of glow 



d. h. „ d. h. 



The diameters have been reduced to the moon's distance 

 on January 12, 1903, viz. 221,820 miles. Whilst not certain 

 of the exact form of the curve after full moon, Prof. 

 Barnard thinks there is no doubt that it rises. 



Two measures of the crater itself gave a mean of o"-63 

 when reduced to the above distance. This corresponds to 

 an actual diameter of about 3600 feet. Other interesting 

 details of the crater and the glow are given in Prof. 

 Barnard's notes. 



