472 



NATURE 



[March 20, 1890 



calculated apparent volume of the standard loo c.c. The size 

 of the tube is so arranged that this mark falls on the narrower 

 portion of the tube, just below the expanded part. The pres- 

 sure tube C is then raised or lowered until the mercury in 

 B stands at the mark, when the stopcock at the top of B is 

 closed. Thus a volume of air is enclosed which at o° and 

 760 mm. and in the dry state would occupy exactly lOO c.c. 

 In order to determine the corrected volume of a gas it is then 

 only necessary to introduce it into the measuring tube A, allow 

 it to cool to the temperature of the room, and then adjust B 

 until the mark is a little higher than the mercury meniscus in 

 A ; C is next raised until the mercury in B rises to the mark, 

 when B and C are finally simultaneously lowered until the level 

 of the mercury in A and B is the same. The gas in A and the 

 air in B are evidently equally compressed, and thus the volume 

 read off upon the measuring tube A represents the corrected 

 volume at o° and 760 mm. The simplicity of the arrangement 

 and the rapidity with which it can be worked are sure to recom- 

 mend it for general use ; and its applicability to the estimation of 

 nitrogen in organic substances, which Prof. Lunge discusses in 

 detail, will doubtless be especially appreciated by those who 

 employ the volumetric method. 



The additions to the Zoological Society's Gardens during the 

 past week include two Red Tiger Cats {Felis planiceps ]v.) from 



Malacca, a Fish Eagle {Polioaetiis ichtliyactiis) from the 



Himalayas, deposited ; a Gayal {^Bibos frontalis 9 ), bom in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Objects for the Spectroscope, 

 Sidereal Time at Greenwich at 10 p.m. on March 20 = 



9h. 53m. 31S. 



Remarks. 



(i) This nebula is described in the General Catalogue as 

 ' ' Very bright ; large ; very much extended in a direction 45° ; 

 at first very gradually, then very suddenly much brighter in the 

 middle to an extended nucleus." The spectrum of the nebula 

 was observed by Lieut. Herschel in 1868, but his observations 

 are not quite complete. He states that a continuous spectrum 

 was suspected, and that there were probably no lines present. 

 Further observations are obviously required. 



(2) A star of Group II. Duner states that the bands 2-8 are 

 well seen, but that 4 and 5 are somewhat feeble. The spectrum 

 is not strongly marked. The star is probably approaching the 

 temperature at which the bands will be replaced by lines, and 

 affords an opportunity of studying the order of the appearance 

 of the lines. 



(3) A star of the solar type (Gothard). The usual differential 

 observations are required. 



(4) A star of Group IV. (Gothard). The usual observations 

 are required. 



(5) One of the finest examples of stars with spectra of Group 

 VI. Duner states that the four bright zones and all the bands 

 which he has numbered l-io are visible. In this star, band 6 

 is weaker than the other carbon bands. Band 5 is strong : I, 2, 

 and 3 are weaker ; and 7 and 8 are visible with difficulty. 



(6) This variable will reach a maximum on March 28. The 

 period is about 146 days and the magnitudes at maximum and 

 minimum 6 "5-7 '5 and io-lo"9 respectively (Gore). The spec- 

 trum is a remarkable one of the Group II. type, and the 

 great range suggests the possible appearance of bright lines at 



maximum, as in R Andromedse, &c., observed by Mr. Espin. 

 Mr. Espin has noticed that in the variables, where F is very 

 bright, the bright lines do not appear until some time afte>- the 

 maximum. It is therefore important to continue observations 

 for a considerable period. 



(7) No record of the spectrum of this variable appears to 

 have been published. The period is about 176 days. The 

 magnitude at maximum is 9-9 '5, and that at minimum 1 3 "5 

 (Gore). A maximum will be reached about March 23, 



A. Fowler. 



The M^gueia Meteorite.— This meteorite was observed 

 to fall at Megueia, in Russia, on June 18, 1889, and a short 

 account of Prof. Simaschko's analysis of it is found in the 

 current number of L'Astronomie. It is noted that the meteorite 

 belongs to that remarkable division containing carbon in com- 

 bination with hydrogen and oxygen. The meteorites of this class 

 are Alais, 1806, Cold Bokkeveldt, 1838, Kaba, 1857, Orgueil, 

 1864, and Nogoya, 1880. The Megueia meteorite is covered with a 

 thin (o'5 mm.) crust, is black, partly dull and partly shiny, and 

 somewhat friable. A microscopical examination showed dark grey 

 specks distributed through the black mass, varying in size from a 

 mustard-seed to a hemp-seed. These grey specks have a more or 

 less chondritic structure, and are different in composition from 

 the mass of the meteorite. Besides these chondrules, the 

 greenish, semi-transparent particles of olivine are seen as in 

 almost all other meteorites, whilst nickel-iron is disseminated 

 through the mass in small grains, and occurs in a half-fused state 

 on the crust. Account is also given of white angular scales, 

 much resembling certain fossils, but this is not the first time that 

 the chondrules with their eccentrically radiating crystallization 

 have been mistaken for organisms. Like other carbonaceous 

 meteorites, that of Megueia has a bituminous smell. 



The Velocity of the Propagation of Gravitation. 

 — M. J. Van Hepperger, in a paper read before the Vienna 

 Academy of Science, has assigned an inferior limit to the velo- 

 city of propagation of gravitation. It results from this limit 

 that the time taken by gravitation to travel the radius of the 

 earth's orbit does not exceed a second. 



The Vatican Observatory.— The work to be undertaken 

 at this new Observatory will be in connection with meteorology, 

 terrestrial magnetism, seismology, and astronomy. The astro- 

 nomical portion will mainly be directed to the photography of 

 the sun and other celestial bodies, and to take part in the con- 

 struction of the photographic map of the heavens, under the 

 direction of the International Committee. 



Double-star Observations. — Mr. S. W. Burnham, of the 

 Lick Observatory, gives his sixteenth catalogue of double-stars 

 in Astronomische Nachrichten, Nos, 2956-57. The observa- 

 tions were made in May, June, and July 1889, and 62 new pairs 

 have been discovered and measured during this period. 



Sun-spot in High Latitudes. — The Comptes rendus of the 

 Paris Academy of Sciences for March 10 contains a short note 

 by M. G. Dierckx, in which he states that he observed a sun- 

 spot on March 4 in N. lat. 65°. If this were substantiated, it 

 would be an almost unprecedented observation. But the photo- 

 graph of the sun taken at the Royal Observatory, Greenwich, 

 on that day, shows no trace of a spot in so high a latitude. A 

 fine group did indeed appear on the sun on March 4, but its 

 latitude was only 34°. This, however, is a very interesting 

 circumstance, for though spots have been observed at consider- 

 ably greater distances from the equator, they have usually been 

 only small, and have lasted but a few hours, or two or three 

 days at most. It would seem probable, therefore, this is the 

 group which M. Dierckx observed, but that he made some 

 error in determining its latitude. 



GEOGRAPHICAL NOTES. 



The limits of the ever-frozen soil in Siberia are the subject 

 of a paper by M. Yatchevsky, in the Izvestia of the Russian 

 Geographical Society (vol. xxv. 5). It is now generally ad- 

 mitted that Karl Baer's criticism of Middendorff's measure- 

 ments in the Sherghin shaft at Yakutsk — from which measure- 

 ments Middendorff concluded that the depth of frozen soil at 

 Yakutsk reaches 600 feet — are well founded. The walls of the 

 shaft, which was pierced seven years before Middendorff came 

 to Yakutsk, had cooled in the meantime through the free access 

 of cold air, and therefore a smaller increment of increase of 



