6i6 



NATURE 



[April 27, 189; 



Amidophosphoric acid crystallises in tabular or short 

 prismatic crystals which are insoluble in alcohol, but readily 

 soluble in water, to which they impart a sweetish taste. The 

 solution is readily distinguished from phosphoric acid inasmuch 

 as it yields no precipitate with silver nitrate. It evolves no 

 ammonia upon treatment with caustic alkalies, but merely 

 forms the salt of the alkali metal. The solution slowly decom- 

 poses into ammonium phosphate. The solutions of the acid 

 and neutral salts of the alkaline metals yield many correspond- 

 ing acid and neutral amidophosphates of other metals by double 

 decomposition with soluble salts of those metals. 



Notes from the Marine Biological Station, Plymouth :— 

 Last week's captures include Phoronis hippocrepia, the Actinian 

 Corynactis viridis, and the Foraminiferan Haliphysema. In 

 the floating fauna the Ccclenterate element remains unchanged ; 

 the larva of the Nemertine Cephalothrix have made their first 

 appearance for the year ; the number of Polychaste larvae and of 

 Cirrhipede Nauplii\\a.% become considerably smaller ; the later 

 stages of various Decapod Crustacea [Megalopa, Mysis-%i2igts) 

 have appreciably increased in numbers ; and minute young 

 Oikopleurce now occur in considerable quantity. The "gelatin- 

 ous alga " and Rhizoselenia are extremely abundant. The 

 Hydroid Tubularia bellis, the Gastropod Nassa reticulata, and 

 the Decapod Crustacea Pagtirus lavis, Galathea squamifera, 

 Porcellana platychehs and Pilumnus hirtellus are now 

 breeding. 



The additions to the Zoological Society's Gardens during the 

 past week include an Orang-Outang {Simia satyrtis, 6) from 

 Borneo, presented by Mr. Thomas Workman ; a Spotted 

 Ichneumon {Herpestes nepalensis) from India, presented by Lady 

 Blake ; a Raven {Corvus corax) British, presented by Lady 

 Rose ; a Peregrine Falcon {Falco peregrinus) British, presented 

 by the Old Hawking Club ; a Greek Tortoise ( Tesludo grceca) 

 European, presented by Mrs. Alcock ; a Martineta Tinamou 

 {Calodromas elegans) from Argentina, three Spotted-sided 

 Finches {Amadina lathami) from Australia, purchased ; a 

 Panama Amazon {Chrysotis panamensis) from Panama, received 

 in exchange ; six Indian Wild Swine {Sus crtstatus), four 

 Barbary Mice {Mus barbarus) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Large Telescopes. — Much has been written during the last 

 few months with reference to the usefulness or non-usefulness of 

 large telescopes. That the verdict is given in favour of the 

 former is not at all surprising, for are we not far away from the 

 limit, if there be one, beyond which larger instruments will be 

 available ? Dr. Common has many times pointed out the practic- 

 ability of constructing large reflectors (his five-foot being a good 

 example of the type of instrument he could enlarge), while the 

 Lick instrument, the work of the Clarks, is really only a beginning 

 of what will be done in large telescope building. For refractors 

 it has many times been urged that the increase in size of lenses 

 involves such a thickness that much light is thereby lost by 

 absorption. M. Alvan G. Clark, with reference to this particular 

 point, says a few words in Astronomy and Astrophysics for 

 April, in which he points out that such is not the case. Greater 

 aperture means greater light-grasping power, and as it is quite 

 unnecessary to considerably increase the thickness of the lens, 

 the former predominates over the latter. With the forty-inch 

 discs, he says, only a combined thickness of four inches is 

 required, and with lenses of an object-glass of even six feet 

 aperture a combined thickness of only six inches would be 

 necessary. It is pleasing to hear through him that a steady 

 improvement is being made in manufacture of glass, and that 

 the present discs are infinitely superior to the early ones, and 

 "who knows," as Mr. Clark says, "how soon still moretrans- 

 parent glass may be at hand." 



Spectrum of 5 Lyr/E. — The extreme interest that lies in this 

 variable, especially for spectroscopists, makes it a subject of keen 



NO, 1226. VOL. 47] 



research, and the important observations made by Prof. Keeler 

 with the great Lick refractor, and contributed to the num- 

 ber of Astronojny and Astrophysics for April, will be the more 

 eagerly read. The observations were undertaken with theintention 

 of connecting possible changes in thespectrumof the star with its 

 period of light variability. After plotting a number of obser- 

 vations on the light curve of the star, the recorded appearances 

 of the spectrum " were in some degree contradictory," although 

 certain results were obtained, but they were left incomplete, 

 owing to Prof. Keeler's withdrawal from the observatory. The 

 results may be briefly stated as follows : — 



(i) Bright hydrogen lines C and F, bright D3 line and dark 

 D lines are always visible with the Lick refractor. Certain 

 fainter bright lines are absent only at principal minimum. 



(2) Light variations due to changes in brightness of continuous 

 spectrum. 



(3) Bright lines brightest when continuous spectrum brightest. 



(4) Bright lines broad and diffuse, particularly when star at 

 maximum. D lines very hazy, so that components are hardly 

 distinguishable. 



(5) No really remarkable changes in the appearance of the 

 spectrum took place during greater part of period. Observations 

 show no relation between spectral changes and secondary 

 minimum of the star. 



(6) Most remarkable changes at principal minimum. "The 

 bright lines became dimmer and perhaps sharper. The fainter 

 bright lines disappear. The D lines become darker. Strong 

 absorption lines appear on the more refrangible side of certain 

 bright lines in the green, the separation of the dark and bright 

 lines being at least five-tenth-metres. Other bright lines are per- 

 haps similarly affected. A narrow dark line appears above the D:^, 

 line at the same time. Shortly before the first maximum is 

 reached the dark lines disappear." 



Prof. Keeler adds that the method of observation he adopted 

 was only capable of allowing him to observe a " part of a much 

 more complex series of changes " which no doubt takes place. 



Soci£,TK ASTRONOMIQUE DE FRANCE.— In the Bulletin of 

 this society for 1892, the sixth year since its foundation, several 

 articles of importance will be found to be scattered throughout 

 its numerous pages. Of these we may refer our readers to some 

 selenographic studies by MM. Gaudiberi, Flammarion, and 

 Antoniadi, examination of recent studies of Jupiter by M. 

 Flammarion, and M. Edouard Foulsere's graphical method of 

 determining the co-ordinates of solar spots. The valuable ob- 

 servations made by M. E.-L. Trouvelot on the planets Venus 

 and Mercury, a full account of which has been given in these 

 columns (Naturk, vol. xlvi. p 468), will also be found here, 

 together with a discourse by M. F. Tisserand on the movement 

 of the moon, with reference to ancient eclipses. Among other 

 communications M. Schmoll gives a summary, with tables, of 

 the solar spots observed during the year 1891, M. Guillaume 

 describes his observations on the surface and rings of Saturn, and 

 MM. Quenisset and Trouvelot contribute their observations on 

 planets and remarkable solar protuberances respectively. A 

 simple method of determining the positions of solar spots, and 

 of measuring their displacements, is treated by Dr. Huette, 

 while M. Bruguiere gives a most interesting account of M. 

 Lippmann's work on photography in colours, and M. Pluvinel 

 on the coming (now past) eclipse of the sun. 



WoLSiNGHAM CIRCULAR, No. 34.— With reference to the Con- 

 tents of the Wolsingham Circular, which we recently gave, Dr. 

 Kreutz, in Astronomische Nachrichten, says: — "The first star, 

 Esp.-Birm 180, is certainly given by Chandler as (2258). 

 Aurigse in his list of probable variable stars A. J. 216 ; see also 

 Astronomische Nachrichten, 2764, p. 63, No. 2. The second 

 star is evidently identical with B.D. -f sfl^l = A. G. Hels. 

 3032. Position for 1900 : 3h. 23m. 23s., -f 58° 9' 'o. The 

 original magnitudes of the Hels. zones are : 9'im (February 15, 

 1872), and9-om. (February 15, 1873). 



Astronomical Journal Prizes. — The judges appointed by 

 the editor of the Astronofnical journal sa.y a few words in the 

 current number (No. 293) with reference to some general con- 

 siderations connected with the presenting or withholding of the 

 awards. For comet observations, allowance for optical qualities 

 of telescopes will to a certain extent be made ; relative freedom 

 from systematic peculiarities of observation will be regarded "as 

 a mark of excellence. Even more important than the nominal 

 or apparent precision in other respects." For individual pre- 

 cision of observations, freedom from lari-e or abnormal errors 



