4'i2 MisceltaneoHn Intelligence. 



these signals would be visible, a heliotrope and a sexlant were 

 placed two geographical miles from -each other, the luminous 

 points reflected by those mirrors could be seen by the naked eye, 

 and when viewed through the telescope of the theodolite were 

 too brilliant to give exact points ; but when, in place of the sun's 

 light that from a bright cloud was rcHccted by them, they gave an 

 excellent mark. 



At a distance of five miles, the points were still visible, like 

 stars, by the naked eye, aud they could be seen through the 

 telescope of the instrument, even in heavy weather, when the 

 great signal itself could not be distinguished. At last the distance 

 was increased to 1 1 or 12 geographical miles, the stations being at 

 Inselberg and Hohenhagen, and the operators M. M. Gauss and 

 Enkc. The light was reflected at intervals by the sextant from 

 Inselberg to Hohenhagen, whilst the light was constantly re- 

 flected from the latter to the former place by the heliotrope ; these 

 experiments continued 10 days in various circumstances with 

 great success. Each observer reciprocally saw the points at the 

 other station, whilst frequently the mountains on which they 

 were placed could scarcely be seen by the telescope. More than 

 once the light of the heliotrope pierced through mists and even 

 showers of rain. 



In general the angles observed by these signals were in greater 

 accordance with each other, than when the ordinary signals have 

 been used. 



Baron de Zach proposes a simplification of the reflecting appa- 

 ratus. He supposes a polyhedral reflector, similar to those some- 

 times used by bird-catchers, to rotate on an axis passing through 

 the number of its facets, there will then continually be a facet 

 reflecting the light in the proper direction ; and farther, such a 

 signal would be visible in all directions. In a trial of this 

 process made in the small way, a piece of rock crystal, cut with 

 many facets, was made to rotate rapidly in the sunshine, it was 

 seen distinctly from all situations at the distance of 2,000 toises. — 

 Bib. Univ. xviii. 131. 



2. New Observatories. — Three new observatories have been 

 established in countries the most remotely situated from each 

 other: — at Nikolajen, on the borders of the Black Sea; at the 

 Cape of Good Hope ; and in New Holland. 



3. Astronomical Prize. — The medal founded by IM. de Lalandc, 

 to be given annually to the person who, in France, or elsewhere, 

 has made the most interesting observation in astronomy, or rather 

 the memoire most useful to its progress, has not been adjudged 

 in 1822. So that the prize for 1823 will be doubled, and will 

 consist of a gold medal, value 1,270 francs. It will be adjudged 

 in March 1823. 



