I So 



NATURE 



[June 20, 189 = 



<-*/>»« /ert-^//i»«) from Australia, two Nicobar Pigeons ( Ca&naj 

 nuobarica) from the Indian Archipelago, purchased ; a 

 Reticulated Python (Python retuiitata) from Malacca, received 

 in exchange ; a Thar (Capra jemlaiia, 9 ), a Red Deer {Cervtis 

 elafhtis), txjrn in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 OccULTATlON OF Reoulus. — On June 26 there will be an 

 occullation of Regulus, magnitude I '5. The disappearance will 

 take place at S.4 p.m., while the sun is still above the horizon, 

 and the star will reappe-nr at S.56 — that is, about 37 minutes 

 after sunset at Greenwich. The point of disappearance will be 

 at an angle of 147° from the north point towards the east, and 

 of reappearance at 275° reckoned in the same direction. The 

 age of the mi»n will be a little less than 4 days. 



The RECfRRENCE OF Eclipses. — A new period of the re- 

 currence of eclipses, which promises to be of great use in the 

 discussion cf ancient eclipses, has been investigated by Prof. 

 J. M. Slockwell. (Aslronomual Journal, No. 346.) He 

 points out that 372 tropical years are very nearly equal to 4601 

 iunations, and also very nearly equal to twenty revolutions of 

 the moon's node ; thus: 



372 tropical years = 135870-10348 days. 



4601 lunations = :35870'23425 ,, 



20 revolutions of node = 135870700 ,, 



During this period, the change of mean longitude of the sun and 

 moon at the time of new moon is - 5'''057, of the longitude of 

 the moon's perigee +11 '■464, and of the longitude of the 

 ascending n^ide +o''02l. The precession of the equinoxes 

 during 4601 lunations amounts to 5°'I368, so that the mean 

 longitude nf the sun and moon when referred 10 the movable 

 equinox only changes by o''0797 in a ]5eriod of 372 years. From 

 .this it follows that if an eclipse hap|iened on a given day of the 

 tropical year, there would !«.■ another eclipse on the same day of 

 the tropical year 372 years afterwards. 



As an example of the application of this new cycle. Prof. 

 Stockwell gives [larticulars of an inquiry into an eclipse of the 

 sun which is said to have been observed in China on the day 

 of the autumnal equinox during the twenty-second century H.c. 

 According to Op[)olzer, an eclipse occurred at the autumnal 

 equinox in the year B.C. 1039, October 3, and going back three 

 periods of 372 years, the year 2155 B.C. is de<luced ; other 

 eclipses about this time are found by adding multiples of nineteen 

 years to that date. The discussion of the conditions shows that 

 the eclipse which satisfies the tradition occurred on October 10, 

 2136 B.C. ; this would Ix.- visible as a partial eclipse over nearly 

 the whole uf China, .\ccording to a well-known story, the 

 ;istronomers Ho and Hi were put to death for having failed to 

 predict this eclipse. 



Variabii.i rv OK Nebi'I.t-:. — One of the best authenticated 

 cases of a variable nebula is that discovered by Hind in 1852 in 

 the constellaticjn Taurtis. The nebula was then easily seen in 

 ordinary telescoj>es, but D'Arrest was quite unable to see it in 

 Ocl<il«;r 1861, though it was detected shortly after as an ex- 

 ceedingly faint object in the Pulkowa refractor, and in the fol- 

 lowing year was seen a little brighter with the same telescope. 

 In 1868, however, the nebula was invisible lo .Struve, but 

 another nebula was discovered 4' preceding. Struve's nebula 

 was subsequently observed by D'.VrresI, who testified to its 

 aljscncc in previous observations of the nelghbourhoo<l ; it was 

 seen also by Tenipcl in November 1877, but was not visible lo 

 him a month later. The in'eresl att.iching to this region w.is 

 1; ' 'len, in 1890, Mr. Uurnham found that t Tauri w.is 



1 ncbul'isity ; this was confirmed by Prof. Barnard, 



V. served th.it Hind's nebula was only just visible with 



the l,n:k leleM:o|>c, while Struve's nebula was not [jerceplible. 

 In a i>aptr rtcenlly comniunic.itcd to the Royal Astronomical 

 .Society, I'l'.f. Hamard stales that on February 25 of the present 

 year he fnund Hind's nebula to \k an easy object, while .Struve's 

 ii ' ' ' the nebulosity round t Tauri ha<l pr.icti- 



lurlher observations on March 24 

 sli • . Iiula was again scarcely visible, while 



T Tarn ' bulous, and a faint nebula was suspected 



in the ; 10 .Stnive's nebula (Ohsenatory, June). 



It thu:, .i|>|x;;iM lliat there are really three variable ncoula' in 

 this region, and the observations rather suggest that there is a 

 oonncction lictween them. In 1890, Prof. Keeler found that the 



NO. 1338, VOL. 52] 



nebulosity round t Tauri was probably of the bright-line type, 

 but nothing seems to be at present known as to the spectra of 

 Hind's and Struve's nebul.v. On the meteoritic hyjxithesis, 

 changes in the brightness of nebul.-e are due to the interpenetra- 

 tion of nebulous streams and sheets. 



The Zi-ka-\vei Observatory. — The Zika-wei(or Sicawei) 

 Observatory, near Shanghai, w.-is founded in 1S73 by the French 

 Rom.an Catholic Mission of Kiang-nan, and provided with the 

 instruments necessary for the study of meteorology and terrestrial 

 magnetism. .Since that time, excellent service to commerce and 

 to science has been rendered by the Observatory, l>y the daily 

 publication of weather bulletins, and the issue of a number ofim- 

 jwrtant memoirs. Up to the present, however, astronomy has 

 received little attention at Zi-ka-wei. Twelve years ago, the 

 Municipal Council of the French Settlement furnished the 

 Observatory with a small transit instrument for time determina- 

 tions in connection with the time-ball service then established, 

 but that instrument represents the whole astronomical oxitlit. 

 Recognising this deficiency. Father Chevalier, the Director of the 

 Observatory, has made an appeal for funds to purchase a good 

 cqu,atorial telescope. The English Settlement at Shanghai has 

 voted a sum of ^400 towards the cost of the instrument, and the 

 French Settlement has granted a like amount. The shipping 

 companies at Shanghai have also ))romised a sum of about £400, 

 so that ;^I200 may be taken to be already available. But Father 

 Chevalier wishes to have an instrument with an aperture of about 

 twenty inches, and for this the money already subscribed is in- 

 suflicient. He has therefore appealed to friends of science in 

 France, .\merica, and England lor a sun) of about ^1000 more. 

 If this is contributed, he hopes to h.ave erected a great equatorial, 

 and to accomplish v.aluable work wjth it. 



THE ROYAL SOCIETY CONVERSAZIONE. 



'T'HE rooms of the Royal Society .at Burlington House were 

 •*• filled last Wednesday evening, when the annual conversa- 

 zione to which ladies are .idmilted took place. .Some of the 

 exhibits were shown at the conversazione on .May i, and have 

 already been described in these columns. Follow ing our usual 

 custom, we only give descriptions of new exhibits. 



Perhaps the most striking feature of the evening was the tele- 

 phonic communication with Edinburgh, Glasgow, Belfast, and 

 Dublin, |)raclically shown by the Postmaster-General. The line 

 used is the first link of the great Trunk Telephone System 

 erected by the Post Office, which will eventually place the chief 

 towns in the British Isles in direct communication with e.ach 

 other. The wires lo Irelaiul extend thnmgh Leeds and Carlisle 

 to Portpalrick, thence by cable .across the North Channel to 

 Donaghadee, anil thence to Belfast anil Dublin, the distance by 

 this route from London lo Dublin being 467 miles. The lines 

 are so carefully laid that it was easy to converse with persons at 

 the places connected by lliem, without being disUirlied by the 

 foreign .sounds usually associated w ilh telephonic communicalions. 



An electograph for indelible linen marking w.as .shown by 

 Messrs. Nalder Bros, and Co. The instrument is u.sed as fol- 

 lows : the fabric is damped and a current is passed for about 

 two seconils from a silver die, carrying silver into the fabric 

 wherever the die touches. The current is then reversed for 

 three .seconds, which reduces the silver in the fabric ; the final 

 result being the same as with ordinary marking-ink, viz. that 

 metallic silver is deposited in the tissue. Plain water can be 

 used, but a salt .solution is preferable, as the result is much more 

 quickly obtained. 



.Mcxlels illustrating Lewis and Hunter's patent coal shipping 

 system, .as in use at the Bute Docks, Cardiff, were exhil)ited by 

 the Bute Docks Company. With this system the coal isship|>ed 

 in very much bcller ccmdition than with the old systems, ami 

 owing lo the construction of the carrying-boxes, with a cone 

 valve or bottom, which is only relcsused lo let the load out when 

 it is lowered down into the hold of the vessel, within some 

 18 inches of the flooring of the ship or the cargo, .aslhecase m.ay 

 l>e, the breakage is greatly reduced. Each crane is capable ot 

 loading 300 tuns per hour. 



Prof C. V. Boys jlluslrated the projection of ripples, and 

 showed a logarithmic chart of wave and ripple velocities and 

 frequencies. Kipples produced by tuning-forks are so small, 

 an<l travel so cpiickly, as to be invisible unless illuminated either 

 instantaneously or intermiltcntly at the proper rale. They are 

 then visible, and the relations of velocity and freipiency can be 



