192 



NATURE 



\_7an, 6, 1876 



By using the perennial species exclusively or mainly, it 

 would be possible to depend solely or essentially upon 

 specimens thus attached, and having these always in 

 reserve, luthlessly to exterminate any young individuals 

 which might spring up at inconvenient times and places 

 or in superabundant numbers, although it is more probable 

 that our marine friends would in most cases save all 

 trouble upon this point by anticipating the process. 



Whoever among the managers of our public institutions 

 will have the enterprise to try this experiment will pro- 

 bably set at rest one of the unsolved problems of aqua- 

 rian management, and open up a new field of public 

 interest and of scientific research by largely extending the 

 list of animals which it is possible to keep in a state of 

 health in the marine aquarium. 



A. W. Wills 



THE NEW OBSERVATORY AT VIENNA 



IN the Monthly Notices for November is an interesting 

 paper by Dr. De la Rue on the preparations which 

 are being made on the Continent for promoting physico- 



astronomical observations. The paper refers mainly to 

 the new observatory which is being erected at Vienna, 

 and the illustrations which we are able to give will enable 

 our readers to form some idea of the plan of the 

 building. 



Fig. I represents the south front of the observatory, the central entrance opening into the dwelling of the dir .■cto r, which is to the south of the 



large domei -4t,agi %fK%S2i^^ ^^J^ »:-_J 



" It is scarcely necessary for me to tell the Fellows of 

 the Royal Astronomical Society," Dr. De la Rue says, 

 " that their favourite branch of our science, namely, the 

 physics of astronomy, is now engaging the earnest atten- 

 tion of foreign professional astronomers to a greater 

 extent than obtained only a few years ago, and that grand 



preparations are now being made at several Continental 

 State-observatories to grapple with the important truths 

 which can only be revealed by adequate instrumental 

 appliances such, indeed, as are far beyond the reach of 

 most private fortunes. It was a matter of satisfaction to 

 me to learn that photographic observatories are to be 



AMILCZIK-Wlt 



piG 2, drawn on a smaller scale than Fig. i, shows the general arrangement of the establishment in plan. A B is the great dome, 42 feet in diameter ; this 

 dome is surrounded at its lower portion by the central hall C C, which will contain all the portable instruments. From this central hall access is 

 obtained to the terraces D, adapted for observations with portable instruments or the naked eye. The rooms E and F will receive the meridian 

 instruments, and in G is to be placed the prime vertical. The smaller domes, H, I, and K are each 25 feet in diameter ; besides the instruments 

 spoken of in the text, one of these domes will most probably be equipped with an altazimuth or a heliometer. 



included in at least two of those observatories, namely, 

 in Paris and Vienna," 



Dr. De la Rue refers to the old Vienna Observatory, 

 which was founded in the year 1753, and rebuilt in 

 1826-27, but has been long so crowded round by other 

 buildings as seriously to interfere with the satisfactory 

 performance of astronomical work. After repeated repre- 



sentations to the Austrian Government, the present DirecS 

 tor, M. C. von Littrow, obtained in 1873 the sanction of 

 the Minister of Public Instruction, K. von Stremayer, 

 for the erection of the building which is now approaching 

 completion. The new observatory is about three miles 

 to the north of the centre of the city, and was not com- 

 menced before Prof. Weiss, First Assistant at the Obser- 



