448 Clusters and Nebulce. 



The coin engraved below is one of those struck on the occa- 

 sion of the final suppression of Jewish independence, in the 

 reign of Hadrian, after the revolt of Barcocebas. It bears the 

 name of the colony, abbreviated, which in full would be 

 COLONIA AELIA OAPITOLINA : beneath, in the exerque, 

 are the letters COND, being an abbrevia- 

 tion of the word CONDITA (founded). 

 The type is the old colonial one of the 

 Romans, the two bullocks at plough, in 

 allusion to an ancient and primitive Roman 

 custom of attaching as much land to a 

 colony as two bullocks could encircle with 

 a furrow in a single day. The standard be- 

 hind the bullocks intimates that the colony is a military one. 

 The obverse of this coin has the head of the emperor, laureated, 

 with his name and titles. 



CLUSTERS AND NEBULA.— OCCULTATIONS.— 

 THE ACHROMATIC TELESCOPE. 



BY THE EEV. T. W. WEBB, M.A., F.K.A.S. 



CLUSTERS AND NEBULiE. 



We shall have little trouble in recognizing the next object if 

 the telescope is competent to show it. It is by no means re- 

 markable in itself, but, should the suspicions entertained con- 

 cerning it be verified, it will prove one of the most curious 

 objects in the heavens. 



6. The Nebula in the Pleiades. — 1859, October 19. Tempel 

 at Venice discovered with a small instrument a previously un- 

 describcd nebula close to the star Merope in that group, which 

 he says was large and bright, and twinkling in places, similar 

 to a beautiful bright comet. — 1860, December. Peters and Pape 

 at Altona, in tolerably favourable weather, could only perceive it 

 with difficulty in a G-feet telescope. — 1862, Aug. D' Arrest and 

 Schjellerup, with the new great Copenhagen refractor, of about 

 11 inches aperture and 16 feet focus, could not find it in nights 

 when a nebula called " extremely faint" by fgf and " excessively 

 feint" by H was not only easily distinguished, but seen double. 

 Such an apparent change in connection with the fact that a 

 similar and contemporaneous decrease of light had been noticed 

 in two other nebulae in the same region, of course excited 

 great interest. Familiar as observers have become with tho 

 marvellous phenomenon of variable brightness in stars, the 

 evidence of which is rapidly accumulating with each succeeding 



