July 25, 1895] 



NATURE 



505 



Whereas a few years ago the discovery of a new spirillum 

 form was hailed as a bacteriological novelty, we are now con- 

 stantly receiving fresh additions to this interesting group of 

 microbes. With improved methods their detection and isolation 

 have been rendered comparatively easy, and they are now found 

 fairly widely distributed in water. Sanarelli isolated no less 

 than thirty-two different vibrios from the river Seine, sewage- 

 effluent, and pond water, and various authorities in Germany 

 have detected such forms in rivers. So far the larger number 

 have been obtained from river water, and have been but rarely 

 met with in well water ; but quite recently .MM. -V. Zawadzki 

 and (j. Brunner, of the Imperial Institute for I'reventive Medi- 

 cine in St. Petersburg, have discovered and isolated three 

 vibrios from polluted well water, which do not liquefy gelatine, 

 and in other respects are easily distinguishable from Koch's 

 cholera vibrio. As regards their pathogenic properties, it is 

 stated that white mice were quite unaffected when the vibrios 

 were subcutaneously introduced. The investigations and de- 

 scriptions have been carefully done and are fully recorded, and 

 the authors are persuaded that they have discovered new forms. 

 It is, however, difficult to decide this point, for only a slight 

 acquaintance with the literature of the subject is apparent ; and 

 whilst the authors complain that Eisenberg's catalogue of 

 bacteria is out of date, and those of Roux and Lustig are 

 respectively incomplete, they do not appear to have any 

 acquaintance with Percy Frankland's ".Micro-organisms in 

 Water," containing descriptions of over 200 bacteria found in 

 water, neither have they consulted many important memoirs on 

 vibrios which have been published in recent German and Frenc h 

 journals. 



The writer of the note on \>. ITJ, referring to hygrometric 

 observations on the Sonnblick mountain, inadvertently wrote, 

 "atmospheric electricity," instead of "atmospheric humidity, 

 in the second line of the note. 



The additions to the Zoological Society's Gardens during 

 the past week include a Mozambique Monkey (Cenopil/iecus 

 pygerythrus) from East Africa, presented by Mrs. A. Canning 

 Fysh ; a Khesus Monkey (Macaciis r/usiis) from India, pre- 

 sented by Mr. A. Kagele ; an Irish Stoat [Piiloniis hiliernkus) 

 from Ireland, presented by the Viscount Powerscourt ; a 

 Suricate (Stiritale telradaclyla) from South Africa, presented by 

 Miss Dorothy Lowndes ; a Bosch-bok ( Tragelaphus sylvaticus) 

 from South .Vfrica, presented by Mr. W. Champion ; six 

 Orbicular Horned Lizards (/%/-i'«o.fOT«(Z orbiculare) from .Mexico, 

 presented by Mr. E. J. .Scarbrough ; a West .African Python 

 Python sebcr) from West Africa, presented by Mr. Edward 

 Straw ; a Red-sided Tit (Parus variiis) from Japan, a White- 

 browed .\mazon (C/irysolis albifroiis) from Honduras, two 

 Adorne<l Terrapins {Ctcmmys ornata) from Central America, 

 deposited ; a Japanese Deer (Cervus siitt), born in the tiardens. 



OU/i ASTRONOMICAL COLUMN. 



Al TlTl'DE AND .■VziMUTH OF Poi.ARIS.— It IS a matter of 

 common knowledge that the Pole star is about a degree and a 

 quarter from the true pole, so that azimuths and latitudes cannot 

 be direclly <letermined by observations of this star. The usual 

 mode of procedure is to employ tables reducing the observations 

 to the true pole ; a grajihical method of performing this rather 

 tedious reduction, with an accuracy sufficient for most puri>oses, 

 has been devised by A. Tanakadate, of Tokio (Sugakub.-Kizi.) 

 It is shown that the usual formula for the calculation of azimuth 

 corresponds very nearly with the equation of a circle of radius 

 P sec <p {p being the polar distance of Polaris, and <p the 

 latitude of the place of observation), and the centre of which is 



displaced above the origin by an amount equal to /liHL* 



NO. 1343, VOL. 52] 



cos (p. 



An origin being chosen near the middle of a sheet of squaretl 

 |3aper, degrees and minutes are marked off along the axes in 

 both directions, and a circle is drawn on the same scale with 

 radius and displacement of centre adapted to the latitude as 

 defined above. Radiating straight lines drawn from the origin 

 correspond to different hour angles, the line > -o being that 

 along which the centre of the circle is displaced. The abscissa 

 of the point where the line corresponding to the hour angle at 

 which an observation is made cuts the circle, gives <lirectly the 

 azimuth of Polaris, the star being east or west of the true north 

 according as the point lies to the right or left of the origin in the 

 diagram. Neglecting errors of construction, the readings will 

 only differ by a few seconds from the calculated results, and it is 

 shown that even these errors can be reduced by slightly 

 enlarging the radius of the circle. 



If a circle be drawn from the origin as centre, with radius equal 

 /, the diagram can also be used for reducing the latitude from 

 observations of the Pole star by giving a small correction to the 

 hour angle, ^ / tan /; sin t, where // is the observed altitude, 

 and / the hour angle. The ordinate of this circle gives the 

 correction to be applied to the observed altitude in order to 

 obtain latitude. 



It is pointed out in the paper that these principles may easily 

 be embodied in an instrument, and, in fact, such a contrivance is 

 no\y in use among the students of astronomy in the Imperial 

 University. 



Observations of Double Stars.— The measurements of 

 position angles and distances of double stars made at the Paris 

 Observatory from July 1890 to the end of last j-ear, are 

 pidjlished by M. Bigourdan in a very concise form in the 

 Bulletin Astronomiijue for July. The telescope employed was 

 that of the western tower, having an object glass O'JOj m. 

 diameter and a focal length of 5 '25 m., the magnifying power 

 usually being 478. Most of the observations were made in the 

 twilight or in the early night, at which times the star images are 

 at their best. The list of stars observed includes about 150 from 

 the Dorpat catalogue, 76 from the Pulkowa catalogue, and 

 nearly 30 others ; in many cases there are long series of 

 measures of the same pair. A filar micrometer was employed. 



.\t the Berlin Observatory, Dr. \. Knorre has used a double 

 image micrometer in the measurement of double stars, and some 

 of the results are given in Ast. Nacit, 3300. The measures 

 appear to agree ver)- well with those of M. Bigourdan, in the 

 case of stars common to the two sets of observations. 



A GRE.vr Xebui.a in Scori'IO. — In the course of his work 

 on the photography of the Milky Way, Prof. Barnard exposed a 

 plate on the region near Antares for 2h. 20m. on March 25, 

 1895. The resulting negative showed a vast and magnificent 

 nebula, intricate in form, and apparently connected with many of 

 the bright stars of that region, including .\ntares and a Scorpii. 

 The nebula is gathered in cloud-like forms, the greatest masses 

 being around p Ophiuchi and two neighbouring small stars. This 

 photograph was taken with the Willard lensof 6. inches aperture, 

 with which Prof. Barnard has previously obtained such splendid 

 results. 



Even more interesting is a photograph of the same region 

 taken with a "lantern lens" of li inches aperture and 5 inches 

 equivalent focus, the exposure being 2h. i8ni. The scale of 

 this photograph is about 10" to the inch, and in addition to 

 bringing out some new points about the great nebula, it shows 

 the sky itself in that region to he very wonderful. The first 

 photograph hail shown that the nebula occupied a singularly 

 blank part of the sky, from which large vacant channels diverged 

 towards the east, and the negative taken with the lantern lens 

 showed that these channels ran irregularly eastward for 15° or 

 20°. 



The photograph taken with the lantern lens shows that the 

 new nebida extends southward for two or three degrees beyond 

 -Antares and a Scorpii in a southward direction. An elongated 

 nebula about 2° or 3° long, involving the star r Scorpii, is also 

 seen on the photograph. 



Prof. Barnard goes on to say that " this magnificent nebula is 

 one of the finest in the sky, antl as it involves so many of the 

 bright stars in th.at region it would imply that they are 

 essentially at the same distance from us." (Ast. Xacli. 3301). 

 The unpretentious char.actcr of one of the instruments eni'ployed 

 by Prof. Barnard is not the least remarkable feature almut this 

 new discovery. 



