62 R H O 
a man are So little in the hands of the youth of the present 
time.” Julius Caesar Scaliger, who was a pupil of Rhodi- 
giuus, also speaks of him with great esteem, and calls him 
“ The Varro of the age.” Vossii Hist. Lat. Tiraboschi. 
RHODIOLA, [dimin. from Rhodia;] in botany, a genus 
of the class dioecia, order octandria, natural order of suc- 
culentae, sempervivae, ( Juss .) Generic Character.—Male. 
—Calyx: perianth four-parted, concave, erect, obtuse, per¬ 
manent. Corolla: petals four, oblong, obtuse, from erect- 
spreading, double the length of the calyx, deciduous. Nec¬ 
taries four, erect, emarginate, shorter than the calyx. Sta¬ 
mina : filaments eight, awl-shaped, longer than the corolla. 
Anthers simple. Pistil: germs four, oblong, acuminate. 
Styles and stigmas obsolete. Pericarp : abortive.—Female! 
Calyx: perianth as in the male. Corolla: petals four, 
erect, obtuse, equal with the calyx, permanent. Nectaries 
as in the male. Pistil: germs four, oblong, acuminate, 
ending in simple straight styles. Stigmas obtuse. Pericarp: 
capsules four, horned, opening inwards. Seeds very many, 
roundish.—Dahl observed hermaphrodite flowers with ten 
stamens and five styles. This genus therefore might be 
associated with the sedums.— Essential Character. — 
Male. Calyx four-parted. Corolla four-petalled Nec¬ 
taries four.—Female. Calyx four-parted. Corolla four- 
petalled. Nectary four. Pistil four. Capsule four, many- 
seeded. 
1. Rhodiola rosea, common or yellow rosewort.—This 
has a-very thick fleshy root; it has many heads, whence 
in the spring come out thick succulent stalks like those 
of sedum telephium, about nine inches long, closely 
garnished with thick succulent leaves of a grey colour, 
an inch long, and half an inch broad, indented on their 
edges towards the top, and placed alternately on every 
side the stalk; which is tenninated by a cluster of yel¬ 
lowish herbaceous flowers, appearing early in May. They 
have a very agreeable scent, but are not of long continuance. 
—Native of most parts of Europe. There is a smaller va¬ 
riety called rhodiola minor. 
2. Rhodiola biternata.—Leaves biternate gashed, stem 
twining.—Native of Cochinchina, in ill cultivated gardens, 
but not frequent. 
Propagation and Culture —1. Plant cuttings the begin¬ 
ning of April, soon after they come out from the head, in a 
shady border; covering them close down with a glass, and 
keeping them dry: they will put out roots in about six 
weeks. 
RHODITES Lapis, the Rose-stone, in Natural History, 
the name given by authors to a kind of astroites, or star-stone, 
in which the figures more represent roses than stars ; they are 
in both owing to coralloide bodies immersed in the stone; 
which according to their various species, afford a different 
figure, when cut transversely, in cutting the stone into 
.plates for use. 
RHODIUM, a mineral substance. See Mineralogy, 
pp. 479, 507. . , 
RHODIUM Marmor, a name given by the ancients to 
a marble brought from Rhodes; it was a good white, but 
inferior to the Parian, and was used by the Romans in their 
public buildings, and sometimes in statuary. 
RHODIUS (Ambrose), a German mathematical professor 
and physician of some note in the 171h century, was born 
at Kemberg, a town near Wittemberg, in Saxony, in the 
year 1577. Having laid a good foundation of classical 
learning, at the age of eighteen he was sent with an exhibi¬ 
tion from the Elector of Saxony to the University of Wit¬ 
temberg, where he was for some time wholly occupied with 
the study of the mathematical sciences, and afterwards added 
to it that of medicine. Of the proficiency which he made 
in the former, an honourable testimony was given by Mel¬ 
chior Justell, mathematical professor in the University, who, 
when Tycho Brahe, then residing at Prague, requested that 
he would send him a student qualified to assist in his astrono¬ 
mical observations, fixed upon Rhodius, and advised him 
not to lose so favourable an opportunity of improving under 
R H 0 
such a master. This advice Rhodius willingly followed, 
and, after being admitted to the degree of master of philoso¬ 
phy, went to Prague. Here his services gave perfect satis¬ 
faction to Brahe, and also introduced him to the acquaint¬ 
ance and warm esteem of his friend, the famous Kepler. 
How long he continued at Prague we are not infonned ; but 
we learn that, upon quitting that city, he returned to Wittem¬ 
berg, and commenced private lecturer in the mathematics. 
His merits soon recommended him to the favour of the 
Elector, who appointed him professor extraordinary of the 
mathematical sciences in the University, with a regular sti¬ 
pend. In the year 1609, a vacancy taking place in the chair 
of professor in ordinary of the same sciences, he was 
nominated to that post. During the next year he went 
through the requisite public exercises, and took the degree 
of doctor of medicine. He Entitled himself to the last¬ 
ing gratitude of the citizens of Wittemberg, by his exer¬ 
tions as a civil engineer, in supplying the city with whole¬ 
some water, at a considerable expence. After being twice 
honoured with the office of rector of the University, and six 
times with that of dean of the College of Philosophy, he 
died of a stroke of apoplexy, in 1633, at the age of fifty-six. 
He was the author of “ Euclides illustratus et explicates;” 
“Optica;” “ Tactatus de Crepusculis;” De Cometa, qui 
An. 1618 conspectus est;” “ De Matheseos Necessitate in 
Repub] ica;” “ De vera Mundi conditi Epocha, et genuino 
natali Abrahami, Anno, &c.” The editors of Moren’s Dic¬ 
tionary have confounded our author with another physician 
of the same name, who practised at Christiana, in Norway, 
and was appointed professor of natural philosophy and the 
mathematics in the college at that city. He rendered him¬ 
self obnoxious to the government by the part which-* he 
took in politics, and was committed to prison, where he is 
thought to have died, about the year 1633, leaving behind 
him some writings not of sufficient moment to be enumerated. 
Fr-eheri Theat. Fir. Erud. Clar. Witte Diar. Biog. Mo- 
reri. 
RHODIUS (John), a learned physician and antiquary, 
was born at Copenhagen, about 1587. After completing 
his studies in his own country, he went to Padua in 1614, 
for the purpose of receiving the instruction afforded by that 
celebrated school. His residence there proved so agreeable 
to him, that he resolved to fix his abode in Padua; and, in 
order to be perfectly at leisure for his literary and scientific 
pursuits, he refused to enter into a matrimonial engagement 
that was proposed to him, or to accept the chair of botany and 
the superintendence of the botanical garden. When he re¬ 
visited his native city in 1640, he in like manner declined 
a professorship that was offered him; and he returned to 
Padua; where he died, in 1659, at the age of 72. The 
fruits of a life spent in study, were some learned works rela¬ 
tive to medicine and medical antiquities. The first appear 
chiefly to have been observations collected from the Paduan 
professors. Of these are “ Observationum Medicinalium 
Centuries tres;” Patav. 8vo. 1657 ; “ Mantissa Anatomiea 
ad T. Bartholinum;” Hafn. 8vo. 1661; and “ Observati¬ 
ons posteriores” in Act. Hafn. V. iv. His critical and anti¬ 
quarian writings are “ De Acia Dissertatio ad Cornelii Celsi 
rnentem,” Patav. 1639; afterwards printed at Copenhagen 
with the author’s “ Oratio de ponderibus et mensuris, et 
Vita Celsi;” “ Analecta et Notes in Lud. Septalii Animad- 
versiones et Cautiones medicas1652 ; “ Notes et Lexicon 
in Scribonium Largum de Compost'tione Medicamento- 
rum,” a work full of erudition, and highly useful for the 
understanding of the ancient medical writers. Halleri 
Bibl. Med. and Anatom. E/op. Diet. 
RHODODENDRA, in botany, a natural order of plants, 
named after its principal genus, (seethe next article,) and 
constituting the fiftieth in Jussieu’s series, or the second of his 
ninth class. 
Calyx divided, permanent. Corolla inserted into the bot¬ 
tom of the calyx; sometimes of one petal, and lobed; some¬ 
times almost polypetalous, the limb being so very deeply 
divided. Stamens definite, distinct; in the monepetalous 
genera 
