11 YN 
Rut 
Calyx six-leaved ; corolla none ; nectary 
central, ovate, perforated at the top. There 
are five species. 
RUSSELIA, in botany, so named in ho- 
nour of Alexander Russel, M. D. a genus 
of the Didynamia Angiospermia class and 
order. Natural order of Personatse. Scro- 
phularise, Jussieu. Essential character: 
calyx five-leaved, setaceous at the end ; 
corolla tube very long, hairy at the throat ; 
border two-lipped, lower lip trifid ; capsule 
acuminate, one-celled, two-valved, many- 
seeded. There is only one species, viz, R. 
sarmentosa, found by Jacquin about Havana , 
in close woods and coppices. 
RUST of a metal, a word that has now 
given way to the modern term Oxide, 
which see. 
RUTA, in botany, rue, a genus of the De- 
candria Monogynia class and order. Natu- 
ral order of Multisilique. Rutaceae, Jus- 
sieu. Essential character : calyx five- 
parted ; petals concave ; receptacle sur- 
rounded by ten honey dots ; capsule lobed. 
There are seven species. 
RUTILE, in mineralogy, a species of 
the Menachine genus, of a dark blood red 
colour, of various degrees of intensity 
passing to a brownish red. It occurs cry- 
stallized, and the crystals are longitudinally 
streaked ; externally it is shining and glis- 
tening ; internally its principal fracture is 
splendent. It is slightly translucent, brit- 
tle ; it yields a pale yellower orange yellow 
coloured streak. It is easily frangible ; 
specific gravity about 4.2. Without addi- 
tion it is infusible before the blow-pipe ; 
with ■ borax or alkali it affords a hyacinth 
transparent glass. 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 mas- 
sive, 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 liard, brittle, and easily frangible. Spe- 
cific gravity 3.5. It experiences little 
END OF 
change before the blow-pipe, without addi- 
tion, but with borax it forms a yellowish- 
green transparent bead ; the constituent 
parts are different according to the place 
from which the specimens are found ; one 
from Norway was found to consist of , 
Silica 22 
Oxide of menachine 58 
Calcareous earth 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 Frederick Ruysch, professor of 
botany at Amsterdam, a genus of the Pen- 
tandria Monogynia class and order. Essen- 
tial character : calyx five-leaved ; corolla 
five-petalled, reflexed ; style none ; berry 
many-seeded. There are two species, mz. 
R. clusimfolia, and R. surubea. 
RYANIA, in botany, so named in honour 
of John Ryan, M. D. a genus of the Poly- 
andria Monogynia class and order. Essentird 
character : calyx five-leaved, permanent, 
coloured ; corolla none ; stigmas 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 
Grallae. Generic character : the bill greatly 
compressed ; lower mandible considerably 
longer than the upper ; nostrils linear and 
pervious ; back toe very small ; tail very 
forked. R. nigra, or the black skimmer, the 
only species, is twenty inches long and three 
feet and a half in width. It inhabits America 
and the East Indies, and is almost inces- 
santly on the wing, skimming over the sur- 
face of the water, into which it plunges its 
bill with extreme frequency, to seize small 
fishes, which constitute its chief food. The 
structure of its bill enables it to open 
oysters and other shell fish with extreme 
ease, and in stormy weather it is seen on the 
shores opening and devouring them. See 
Aves, Plate XIII. fig. 3. 
VOL. V, 
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