546 



Marvels of the Universe 



those which from ancient times have borne the names of the " Pleiades " and the " Hyades " in 

 the constellation Taurus and the " Prsesepe " in Cancer, familiarl}' known as the " Beehive." 

 These three objects though truly Clusters, are not usually included under that teclinical name, 

 being no more than groups of stars gathered together within a limited area. Of Clusters properly 

 so-called the most striking are those known as 5 M. Librae, 13 M. Herculis. 15 M. Aquarii, and the 

 Cluster surrounding the southern star m Centauri. All these may be described as very bright and 

 symmetrical in outline ; hence they are commonly known as " globular Clusters." Most of 

 Messier's other Clusters are of altogether irregular form, and one of them (11 M. .\ntinoi) was 

 likened by Admiral Smyth to a flock of geese. Another very remarkable Cluster is that in the 



sword-handle of Perseus, 

 the official designation of 

 which is 33 H. VI Persei. 

 This, and a closely ad- 

 jacent group, were well 

 termed by Webb as 

 " gorgeous " and by Smyth 

 were spoken of as " afford- 

 ing together one of the 

 most brilliant telescopic 

 objects in the heavens." 

 1 can confirm both these 

 opinions from personal 

 observation, as the reader 

 can well do for himself, 

 armed with a telescope of 

 even the most moderate 

 power. Indeed, the more 

 moderate the power, the 

 greater will be the sensa- 

 tion to the spectator, be- 

 cause the larger the field, 

 which will therefore em- 

 brace many outlying stars 

 which would be lost to 

 view in a telescope of 

 higher power and therefore 

 more contracted field. 



""■■'^s- Hitherto I have spoken 



under the designation of remarkable Clusters of objects which have a certain amount of concentration 

 and symmetry, constituting, in fact, patches of light in the sky ; but it must not be forgotten that the 

 largest and finest group of stars in the heavens is the Milky Way, the very name of which suggests 

 that its essentially stellar character was not realized by our ancestors, who gave it that name. 



Turn we now to the Nebulas properly so-called. But in doing so we are met at once by the pre- 

 liminary difficulty of the uncertainty which has existed and to some e.xtent must be said still to 

 exist as to when an object can no longer be called a Nebula and must be ranked as a Cluster, and 

 vice versa. It may seem strange to put the matter thus, but the three pictures of the " Dumb-bell 

 Nebula," in Vulpecula, will suggest the propriety of the statement. The topmost picture gives 

 the object as seen in any small telescope. In other words, as a patch of light without trace of 

 star. Seemingly it is a genuine Nebula. 



I'hoto tfu] 



Lying a little south-west of the bright star Eta 

 advanced form than the Orion Nebula, the gaseou 



[//. J. iSfiepslone. 



SPIRAL NEBULA. 



the "Great Bear." It is a more 

 matter condensing gradually into 



