446 



NA TURE 



[March io, 1892 



Taylor; a Sharp-nosed Crocodile {Crocodilus acutus) from 

 Havana, presented by Mr. Arthur Morris ; a Chimpanzee 

 {Anthropopiihecus troglodytes i ) from West Africa, a Bison 

 {Bison americanus I, ) from North America, an Anaconda 

 {Eunectes murinus) from South America, deposited ; a Brazi- 

 lian Tapir (7a/m« americanus 9) from South America, four 

 Hairy-rumped Agoutis {Dasyprocta prymnolopha) from Guiana, 

 a Mexican Agouti {Dasyprocta mexicana) from Mexico, four 

 Scarlet Ibises {Eudocimus ruber) from Para, a Blue and Black 

 Tanager {Tanagrella cyanomelana) from South-East Brazil, a 

 Prince Albert's Curassow {Crax alberti 9 ) from Columbia, 

 purchased. 



OUR ASTRONOMICAL COLUMN. 



Cordova Observatory. — A publication of some importance 

 has recently been issued from the Observatorio Nacional Argen- 

 tino. It contains the observations made under the direction of 

 Dr. Gould, in 1880, for the General Catalogue, arranged and 

 published by Mr. J. M. Thome, the present Director of the 

 Observatory. The mean places of 10,923 stars have been found 

 from 33,837 separate and complete determinations, and this 

 during one year of observation. In addition, 1613 observations 

 of circumpolars, and 1738 of time-stars, have been made for 

 determining instrumental corrections. It is therefore well re- 

 marked that "the dimensions of the volume almost entitle it 

 to the rank of a General Catalogue, and the results for the 

 month of December alone, vi^hen 5938 determinations of posi- 

 tions were made, would form a fair Annual Catalogue." In 

 order to get through this immense amount of work, the meridian 

 circle was manned with an observer, a microscope reader, who 

 also pointed the telescope, and a recorder ; and on four nights 

 of eight hours each, in December, these three observers made, 

 on the average, 1549 complete determinations. And the work 

 has been done in such a thorough manner, in spite of the rapidity 

 of execution, that one cannot but admire the dexterity of Messrs. 

 Bachmann, Davis, and Stevens, who have assisted Mr. Thome. 

 The right ascensions are referred to the "Standard Places of Fun- 

 damental Stars," second edition, published in 1866. The mean 

 places of these stars for the beginning of each year, to 1880 in- 

 clusive, are published in the American Ephemeris tables, and 

 their apparent places in successive volumes. The magnitudes re- 

 corded in the Catalogue are generally the results of estimation. 

 Stars, however, which occur in the " Uranometria Argentina" 

 have had their magnitudes taken from the data collected for that 

 work. Catalogues of southern stars are hardly so plentiful as 

 those containing places of stars north of the equator. This 

 volume is therefore doubly welcome. It represents work carried 

 out in spite of the vicissitudes to which an Observatory in the 

 Argentine Republic must be subject, and the results obtained 

 will be appreciated by all. 



Algol. — In a series of contributions to the knowledge of the 

 variable stars, which has appeared in the Astronomical y our nal, 

 Dr. S. C. Chandler has discussed the periods, motions, and 

 laws of variable stars. His last communication, contained in 

 Nos. 255 and 256 of the Journal, deals with the inequalities in 

 the period of j8 Persei ; the theory which satisfactorily accounts 

 for these and other phenomena being stated as follows : — 

 " Algol, together with the close companion — whose revolution in 

 2d. 20 "Sh. produces by eclipse the observed fluctuations in light, 

 according to the well-known hypothesis of Goodriche, confirmed 

 by the elegant investigation of Vogel — is subject to still another 

 orbital motion, of a quite different kind. Both have a common 

 revolution about a third body, a large, distant, and dark com- 

 panion or primary, in a period of about 130 years. The size of 

 this orbit around the common centre of gravity is about equal to 

 that of Uranus around the sun. The plane of the orbit is 

 inclined about 20° to our line of visio'n. Algol transited the 

 plane passing through the centre of gravity perpendicular to 

 this line of vision in 1804 going outwards, and in 1869 coming 

 inwards. Calling the first point the ascending node, the posi- 

 tion-angle, reckoned in the ordinary way, is about 65". The 

 orbit is sensibly circular, or of very moderate eccentricity. The 

 longest diameter of the projected ellipse, measured on the face of 

 the sky, is about 2" 7. A necessary consequence of this theory 

 is an irregularity of proper motion with an amplitude of some- 

 thing over a fifth of a time-second in right ascension, and nearly 

 one and a half seconds in declination ; the middle point being 



NO. II 67, VOL. 45] 



the centre of gravity of Algol, and the distant unknown com- 

 panion, and the uniform proper motion of the latter being 

 - O'coios. and -f- o""Oi20 annually, in the two co-ordinates 

 respectively. The annual parallax of the star is about o"-o7. 

 The mean period of light variation is 2d. 2oh. 48m. 56"00s." It 

 seems very probable, from Dr. Chandler's communication, that 

 the inequalities in the periods of other variables of the Algol 

 type will admit of a similar explanation. 



The Sun-spots of February.— Some facts with regard to 

 the dimensions of the recent sun-spots appear in the March 

 number of the Observatory. The group of spots apparently 

 connected with the great magnetic disturbance of February 

 13-14, and the aurora which was visible at a large number of 

 places on the latter date, was first seen on the east limb of the 

 sun on February 5. It passed the central meridian six days 

 later, and disappeared rourd the west limb on February 17. 

 "The total spotted area measured on the photographs taken at 

 Greenwich on February 13, when the group reached its maxi- 

 mum, was no less than 1/350 of the sun's visible hemisphere. 

 At Greenwich the area of spots is measured in millionths of the 

 sun's visible hemisphere, and this extensive group had an area 

 of 2850 millionths, corresponding to 3360 millions of square 

 miles. The centre of the group was then at 260° long., and in 

 lat. — 23°. The group was a broad band extending over 22° of 

 longitude in length and 10° of latitude in width, corresponding 

 roughly to a greatest length of 150,000 miles and a width of 

 75,oco miles. The large central spot of the group was 15° in 

 length in longitude and 8° in width in latitude. The spot- 

 group is the largest ever photographed at Greenwich, and is the 

 largest which has appeared on the sun since 1873." 



A New Comet. — Prof. Lewis Swift, of the Warner Observa- 

 tory, discovered a comet on March 6 in R.A. i8h. 59m., and 

 N.P.D. 121° 20'. Unfortunately the comet is at present too far 

 south to be seen in these latitudes. 



Prof.'Krueger {Astronomische Nachrichten,'^o. 3077) con- 

 tributes an important paper on the determination of the per- 

 turbations set up in the motions of periodic comets as they 

 approach the sun, owing to their proximity to the planets. 



PHOSPHOROUS OXIDE. 



T N addition to the well-known pentoxide formed when phos- 

 phorus is burnt in air or oxygen, a second oxide of 

 phosphorus has long been surmised to exist. Very little, how- 

 ever, has hitherto been known concerning this second oxide. 

 It is usually described in current chemical literature as a white 

 amorphous powder of the composition P2O3, very voluminous, 

 somewhat more volatile and more readily fusible than the 

 pentoxide PoOs, and instantly dissolved with great rise of 

 temperature by water, with formation of phosphorous acid. 

 During the last three years an investigation has been carried out 

 in the laboratory of the Royal College of Science by Prof. 

 Thorpe and the writer, which has resulted in showing that 

 phosphorous oxide is a substance possessing properties entirely 

 different from these. Full details of this work have recently 

 been laid before the Chemical Society, but a short account of 

 the manner in which the pure oxide has been isolated in 

 quantity, of its somewhat remarkable properties, and of a few 

 of its more important reactions, may, perhaps, not be uninterest- 

 ing to readers of Nature. 



Properties of P/iosphorous Oxide. 

 Before describing the mode of preparing the oxide, it will 

 be advisable to briefly indicate the external appearance and 

 essential properties of the substance. Phosphorous oxicie is not 

 an amorphous powder, but, at temperatures not exceeding 22" 

 C, a pure white crystalline solid, compact and heavy, soft and 

 wax-like in character. Its most striking property is the ease 

 with which it melts, the warmth of the hand which holds the 

 vessel containing it being more than sufficient to convert it to 

 the liquid state. Its melting point is 22°"5 C, hence upon a 

 warm summer's day or when placed in a warm room it takes 

 the form of a clear, colourless liquid, very mobile, but some- 

 what heavy. It is best preserved in sealed glass tubes, the 

 air of which has been replaced before the introduction of the 

 oxide by carbon dioxide or nitrogen in order to avoid the action 

 of the oxygen contained in air, which rapidly converts 

 phosphorous oxide to phosphoric oxide. When such a tube con- 

 taining the liquid oxide is cooled by immersing it in cold water 

 or allowing it to stand in a room of ordinary temperature (17°- 



