October i i, 1906J 



NA TURE 



595 



search up to thn present lime, considers critically the 

 ■difficulties yet to be surmounted, and suggests several new 

 plans which would possibly prove successful in clearing 

 up outstanding questions. Mr. S. Leonard Bastin dis- 

 cusses the possibility of an intelligence in the plant. The 

 purpose of the paper is to bring together a few instances 

 which seem to point to a limited intelligence in the vege- 

 table kingdom. The cases selected are those not easy to 

 explain as direct response to any special stimuli. The 

 Droserace.ne provide Mr. Bastin with several instances. The 

 sludy of roots and the opening and shutting of floral 

 envelopes add other interesting examples to a readable 

 article. The same number of the magazine contains some 

 reflections upon English and German education, by Mr. 

 K. n. I.attimer. 



The Proceedings of the Royal Physical Society, Edin- 

 burgh, for September (vol. xvi., No. 6), contains an 

 inleresting account of certain blood-inhabiting protozoa by 

 Miss Muriel Robertson, including the description of a new 

 trypanosome from a python. Other papers are a note on 

 a rare sponge from the Scotia collection, by Prof. Arthur 

 Thomson and Mr. J. D. Fiddes ; notes on fossils from 

 thi' Falkland Islands, by Mr. E. T. Newton ; note on the 

 geology of Gough Island, by Mr. J. H. Harvey Pirie ; and 

 notes on the petrology of Gough Island, by Mr. R. 

 Campbell. 



A SEiosii revised edition of Prof. E. Mach's " Erkenntnis 

 und Irrtum " has been published by the firm of J. A. 

 Harth, Leipzig. The original work was reviewed in 

 Xature of November 30, 1905 (Supplement, p. vii). 



The practical treatise on " Nitro-Explosives, " by Mr. 

 P. Gerald Sanford, published by Messrs. Crosby Lock- 

 wood and Son ten years ago, was reviewed in Nature of 

 September 3, 1896 (vol. liv., p. 410). The second edition, 

 revised and enlarged, which has just appeared, embodies 

 accounts of important advances since the publication of the 

 original work, and the chapter on smokeless powders has 

 been considerably enlarged. 



OUR ASTRONOMICAL COLUMN. 



The Rel.mion between the Spectra of Sun-spots and 

 Stars. — The conclusion arrived at by Sir Norman Lockyer 

 regarding the similarity of the spectra of sun-spots and 

 Arcturian stars (Proc. Roy. Soc, vol. Ixxiv., 1904) receives 

 confirmation from a research carried out at the Mount 

 Wilson Observatory. The results of this research are pub- 

 lished by Mr. W. S. .^dams in No. 2, vol. xxiv., of the 

 Astrophysical Journal. During the latter part of June 

 some spectrograms of sun-spots were obtained, including 

 the blue end of the spectrum, and these were compared 

 with a spectrogram of Arcturus secured with the Snow 

 telescope and a grating spectroscope, with a total exposure 

 of twenty-three hours. The comparison showed that a 

 striking resemblance exists between the sun-spot and the 

 star spectra. Not only are the lines intensified in the 

 spot found to be intense in the star, but the absolute 

 intensities are very similar. 



From this evidence Mr. Adams concludes, as did Sir 

 Norman Lockyer, that the physical conditions prevailing 

 in the atmosphere of .Arcturus are nearly identical with 

 those existing in sun-spot vapours. Hence, on the probable 

 supposition that sun-spots are cooler than the general 

 solar photosphere, Arcturus and similar stars must be 

 placed on a lower temperature level than the sun. 



The Mount Wilson Spectroscopic Laboratory. — An 

 interesting illustrated account of the spectroscopic labor- 



NO. 1928, VOL. 74] 



atory attached to the solar observatory on Mount Wilson 

 is given by Prof. Hale in No. 2, vol. x.xiv., of the Astro- 

 physical Journal. As Prof. Hale points out, it is now 

 necessary, if research in solar physics is to produce the 

 most fruitful results, to be able to imitate, as nearly as 

 is possible in the laboratory, the conditions of temperature, 

 pressure, &c., obtaining in the sun. To this end the 

 laboratory at Mount Wilson has been equipped, and the 

 means are always at hand to obtain, immediately, spectro- 

 grams for which the light-source has been subjected lo 

 enormous pressure or temperature, or has been placed in 

 a strong magnetic field, is in an attenuated atmosphere, 

 or, in fact, is under any special conditions which may 

 possibly account for peculiarities observed in the solar 

 phenomena. 



The Utility of Short-focus Reflectors. — In No. 30 

 of the Naturwissenschaftliche Rundschau Dr. A. Berberiib 

 discusses the advantages of short-focus reflectors in nebula 

 photography, and describes the results obtained at Potsdam 

 with an astrographically mounted reflector of 41 cm. 

 diameter and 927 cm. focal length. The mirror is an 

 exceptionally good one, made by Schmidt, of Mittweida, 

 .Saxony, and giving well-defined small images, over a large 

 field, with the full aperture. When the full aperture is 

 used in photographing the Pleiades, the resulting photo- 

 graph, with thirty minutes' exposure, shows all the details 

 of the nebula secured by Prof. Keeler, with the Crossley 

 reflector, in four hours. 



Similarly, forty minutes' exposure on 7 Cassiopeis shows 

 as much detail in the nebula as was obtained by Dr. 

 Roberts, with his reflector of 51 cm. aperture and 250 cm. 

 focal length, in ninety minutes. With the aperture reduced 

 to 24 cm., the Potsdam instrument will photograph the 

 Orion nebula in one hour, and show all the details and 

 all the stars shown on Dr. Roberts's photograph after an 

 exposure of three hours twenty-five minutes. 



Prof. Barnard's "Unexplained Observation." — In a 

 letter to the Observatory (No. 375) Mr. Charles L. Brook 

 suggests that the object seen by Prof. Barnard in 1892, for 

 which he was unable to account by any known object, and 

 therefore published a note on the subject only quite recently, 

 may have been a new star. The reason for suggesting 

 this possibility is that, with but one exception, all the 

 known Novas have appeared in the Milky Way ; and 

 Venus, which Prof. Barnard was examining when he made 

 the unexplained observation, was on that date either on 

 the border of or in the galaxy. 



Jupiter's Sixth Satellite. — .As Jupiter is now approach- 

 ing opposition, the search for the smaller satellites has 

 been commenced at Greenwich. Owing to unfavourable 

 meteorological conditions no photographs were obtained 

 until August 28, but on that date, and on August 31, the 

 sixth satellite was successfully photographed with the 

 30-inch reflector, giving exposures of twenty-eight and 

 forty-five minutes respectively. Several other successful 

 photographs have been obtained since (the Observatory, 

 No. 375). 



Observations of Long-period Variables. — In No. 4116 

 of the .istronomische Nachrichten Prof. A. A. Nijland pub- 

 lishes the results of a series of observations of a number 

 of long-period variable stars. The list includes thirteen 

 .Algol variables, four short-period and forty-one long-period 

 variables, and the observations were made with the lo-inch 

 telescope and 3-inch finder of the Utrecht Observatory, the 

 " step " method being employed. 



THE CONGRESS OF AMERICANISTS AT 

 QUEBEC. 



'T'HE fifteenth International Congress of Americanists 

 was held at Quebec on September 10-15 under the 

 presidency of Dr. Robert Bell, of the Geological Survey 

 of Canada. There were about 133 members and associates, 

 most of whom were Canadians ; a noticeable and pleasing 

 feature of the congress was the large number of French- 



