March i6. 1899] 



NA TURE 



473 



150° C. by traces of carbon monoxide. In an ordinary bats- 

 wing burner, the amounts of carbon monoxide found were so 

 small as to be possibly due to experimental error, and in any 

 case negligible. The ordinary incandescent burner gives off 

 traces of this gas, and in fact whenever a gas flame strikes an 

 obstacle within a certain distance of the orifice through which 

 the gas is issuing, small quantities of carbon monoxide are 

 evolved, and on this account special attention to the upward 

 draught in all gas stoves is essential. No lighting burner in 

 ordinary use appeals to give oft sufficient carbon monoxide to 

 render any special precautions necessary, the author pointing 

 out that more of this gas will be introduced into a room through 

 slightly defective gas fittings than is given out by any pattern of 

 burner in ordinary use. 



The additions to the Zoological Society's Gardens during the 

 jjast week include a Macaque Monkey {Macaciis cynoniolgus) 

 from India, presented by Mr. W. White ; two Great Bats ( Vcs- 

 fcrtilio uoilula), British, presented by Mr. E. Hilton ; a 

 Common Seal [Phoca vititlina) from the River Spay, Scotland, 

 presented by his Grace the Duke of Richmond and Gordon, 

 K.G. ; a Common Hare (Lepus ctiropaeus), British, presented 

 by Miss Henrietta Holland ; an Egyptian Jerboa (Dipus 

 aegyptiiis) from North Africa, presented by Mr. F. Tomlin ; a 

 West African Love Bird {Agapornis pullaria) from West 

 Africa, presented by Mr. C. W. Gameys ; a Kiang {Equtis 

 heiiiioiius) from Tibet, a Rose-crested Cockatoo (Ca^^atoa inohic- 

 censm) from Moluccas, an Echidna (Echidna hystrix) from 

 New South Wales, deposited ; a Cabot's Tragopan [Ceriornis 

 cabotV) from China, five Crested Colins {Eitpsychortyx cristata) 

 from Mexico, purchased. 



OUR ASTRONOMICAL COLUMN. 



Co.MET 1899 a (Swift).— The number of observations of this 

 comet has been sufficient to allow of the orbit being computed, 

 and for this the following elements are found : — 



T = 1899, April 13-26, G.M.T. 



m= 4 54^ 



;■ = 146 4 j '^^g 



'/ = 0-3447 ] 



23 



I -00 

 1-13 



The comet is brightening as it approaches the sun, and its 

 rapidly decreasing southerly declination will render its observ- 

 ation more likely in these latitudes. It is said to be round, with 

 a diameter of about ^' of arc, having a central condensation and 

 a short tail. It should be looked for immediately after sunset 

 near tj Eridani, and will move from that position towards the 

 variable star o Ceti (Mira). 



TuTTi.E's Comet 1896 /;.— In Ast. Nach., 3552, Mr. J. Rahts 

 gives an improved ephemeris of this comet, together with the 

 elements. 



1699. RA. Decl. 



h. m. 



March 17 



The comet is increasing in brightness. 



New Star in Aijuii.a.— A circular from the Centralstelle 

 at Kiel informs us of the present state of the new star discovered 



NO. 1533, VOL. 59] 



by Mrs. Fleming in March 1898, during the examination of the 

 Harvard plates. The position of the star for epoch 1900 is 

 R.A. = l8h. 56n:. 13s.: Decl. = - 13° 18'; this place is in the 

 south-western border of Aquila, or on some charts in the north- 

 west of Sagittarius. At the time of discovery the Nova was of 

 the fifth magnitude, while now (March 10) Prof. Pickering gives it 

 the magnitude ten, as determined from the photometric measure- 

 ment of eight plates. 



Photography ok Corona. — For the past four or five years 

 several astrophysicists have been attempting to obtain photo- 

 graphs of the Solar Corona without the aid of a total eclipse, 

 but so far, however, without success. Sig. A. Ricco, director 

 of the Catania Observatory, gives the history of the investigation 

 as well as the results of his own attempts on the problem. 

 [Bulletin dc la Soc- Beige d' Astronoiiiie, vol. iii. No. 4.] The 

 first attempts described are those of Dr. Huggins, who employed 

 a reflector having an extended cap provided with numerous dia- 

 phragms to minimise the amount of scattered light. A similar 

 apparatus has also been used by A. Mascari at the observatory 

 on Mount Etna. Certain corona-like forms do appear on the 

 photographs thus obtained, but there seems to be no probability 

 of their being real. 



Later Prof. G. E. Hale, using a spectroheliograph at Mount 

 Etna, attempted to photograph the corona by isolating the violet 

 calcium line (K)of the spectrum, and traversing the sun's image 

 given by a lens across the slit of the instrument. This was also 

 unsuccessful. 



Prof. Ricco then tried using a portrait lens, but with no better 

 result ; and the last attempts he describes were made with pin- 

 hole cameras of various dimensions, these also failing to record 

 any true image. Reproductions of the photographs obtained 

 with all four types of apparatus are given, and examination of 

 these shows that the only appearance photographed is the 

 graduated halation effect radiating equally in all directions from 

 the solar disc. 



Harvard College Observatory. — In the Harvard Col- 

 lege Observatory Circular, No. 39, Prof. E. C. Pickering presents 

 some remarks on the work done with the new Bruce photographic 

 doublet in comparison with other instruments of different 

 design. He advocates that in future new large telescopes should 

 be made of widely-varying types, so that the most appropriate 

 form for any particular department of astronomical work may 

 be obtained. The Bruce telescope was a new departure from 

 conventional lines, and its complete success encourages the 

 extension of the inquiry. In this case the instrument has a 

 very short focal length, and Prof Pickering proposes, if funds 

 be forthcoming, to design an instrument of unusually long focus, 

 say from 130 to 160 feet, with an aperture of from 12 to 14 

 inches. This he would place horizontally, and feed with 

 light from a mirror. The diurnal motion would be counteracted 

 by moving the plate by clockwork, as in the horizontal photo- 

 heliograph now in use at Cambridge. Wilh such an instrument 

 he thinks much could be done in obtaining better photographs 

 of the solar surface and the prominences ; pictures of the moon 

 could be got exceeding 12 inches in diameter without enlarge- 

 ment, and possibly photographs of the planets Jupiter, Saturn 

 and Mars. It would also be useful in re-determining the solar 

 parallax from the next approach of Eros in 1900, by observin<T 

 the planet east and west of the meridian. 



C«r«/aj-No..40 gives a description of the methods adopted at 

 the observatory for photographing meteors. In the case of 

 determining the radiant point of bright meteors the usual 

 method of intersecting trails is scarcely applicable, their number 

 being so small. If, however, the meteor is simultaneously ob- 

 served from Hvo stations, the radiant can be determined just as 

 correctly. Provision for this has been made, cameras provided 

 with automatic exposing shutters having been installed at Blue 

 Hill and Cambridge. The lenses are ol wide angle, and point 

 to the zenith. If two photographs of the same meteor are 

 superimposed, the height at the instant of exposure can be 

 found by a simple proportion. As the distance of the meteor 

 on the two photographs is to the focal length of the lenses, so 

 is the distance apart of the two stations to the required altitude. 

 The positions of the trails in space can be found if stars are 

 alsoSphotographed on the plates, the intersection of the two 

 trails giving the declination of the radiant point of the meteor. The 

 right ascension is, however, indeterminate unless time of appear- 

 ance is known, or, as may be later, the camera be mounted 

 equatorially. 



