RUT 



RYN 



passing to a brownish red. It occurs 

 crystallized, and the crystals are longitu- 

 dinally streaked ; externally it is shining 

 and glistening; internally its principal 

 fracture is splendent. It is slightly trans- 

 lucent, brittle - r it yields a pale yellow or 

 orange yello"- coloured streak. It is easi- 

 ly frangible ; specific gravity about 4.2. 

 Without addition it is infusible before the 

 blow-pipe ; with borax or 'alkali it affords 

 a hyacinth transparent glas. It is found 

 to be a pure oxide of menachine, with 

 a slight portion of silica. 



RUTULITE, a mineral found in Nor- 

 way, of a yellowish colour; it occurs 

 massive, disseminated, and crystallized. 

 The crystals are small, singly imbedded, 

 and seldom aggregated. It is translucent 

 on the edges, or opaque, yields a grey 

 streak; it is hard, brittle, and easily frangi- 

 ble. Specific gravity 3.5. It experiences 

 little change before the blow-pipe, with- 

 out addition, but with borax it forms a 

 yellowish-green transparent bead; the 

 constituent parts are different, according 

 to the; place from which the specimens 

 une from Norway was found 

 to consist of 



Silica 



Oxide of menachine 

 Calcareous earth . 



. 22 

 . 58 

 . 20 



100 



It is found at Passau, in the district of 

 the Inn, and in several Norwegian mines. 



RUYSCHIA, in botany, so named in 

 memory of Frederic Ruysch, professor of 

 botany at Amsterdam, a genus of the 

 Pentandria Monogynia class and order. 

 Essential character : calyx five-leaved ; 

 corolla five-petalled, reflexed; style 

 none; berry many-seeded. There are two 

 species, viz. R. clusiaefolia, and R. surubea. 



RYANIA, in botany, so named in ho- 

 nour of John Ryan, M. D. a genus of the 

 Polyandria Monogynia class and order. 

 Essential character : calyx five-leaved, 

 permanent, coloured ; corolla none ; stig- 

 mas four; berry suberous, one-celled, 

 many-seeded. There is only one species, 

 viz. R. speciosa, a native of the Isle of 

 Trinidad. 



RYE. See SECALE. 



RYNCHOPS, the skimmer, in natural 

 history, a genus of birds of the order 

 Grallse. Generic character: the bill great- 

 ly compressed ; lower mandible conside- 

 rably longer than the upper ; nostrils li- 

 near and pervious ; back toe very small ; 

 tail very forked. R. nigra, or the black 

 skimmer, the only species, is twenty 

 inches long- and threp fipt and a half in 

 width. It inhabits America and the East 

 Indies, and is almost incessantly on the 

 wing, skimming over the surface of the 

 water, into which it plunges its bill with 

 extreme frequency, to seize small fishes, 

 which constitute its chief food. It is a 

 vulgar error, that the structure of its bill 

 enables it to open oysters and other shell 

 fish with extreme ease, and that in stormy 

 weather it is seen on the shores opening 

 and devouring them. See Aves, Plate 

 XIII. fig. 3. 



END OF VOL. V, 



