THE 
Jenstb, having acute pointed leaves, on long 
bordered foot-stalks ; flowers axillary, in 
clusters, sitting very close, small, and of an 
herbaceous white colour; male and female 
from the same joint; it is a native of the 
South of France, near Montpelier. 
THEOBROMA, in botany, a genus of 
the Polyadelphia Decandria class and or- 
der. Natural order of Cqlumniferw. Mal- 
vacese, Jussieu. Essential character: ca- 
lyx five-leaved ; petals five, arched ; nec- 
tuary five-horned ; filaments five, within 
the calyx of the petals, growing externally 
to the nectary, having two anthers on each. 
There is but one species, viz. T. cacao, cho- 
colate nut tree, which grows in a very hand- 
some form, to the height of twelve or six- 
teen feet; the wood is light, and of a white 
colour ; the bark is browmish and even ; 
leaves lanceolate, oblong, bright green, en- 
tire, from nine to sixteen incJies long, and 
from three to four in the widest part, on a 
petiole an inch in length, thickened at both 
ends ; peduncles slender, eight or ten toge- 
ther, chiefly from the scars of fallen leaves ; 
flowers small, reddish, inodorous ; fruit 
smooth, yellow and red, about three inches 
in diameter; rind fleshy, half an inch in 
thickness; pulp whitish, the consistence of 
butter, separatiiig from the rind in a state 
of ripeness, and adhering to it orily by fila- 
ments, which penetrate it and reach to the 
seeds ; when the seeds are ripe, it is known 
by the rattling of fhe capsule when shaken. 
This tree bears leaves, flowers, and fruit, 
all the year through; the usual seasons for 
gathering the fruit are June and Decem- 
ber ; one tree yields two to three pounds of 
seeds annually. It is a native of South 
America ; it is also found in several places 
between the Tropics, particularly at Ca- 
racca and Carthagena, on the river Amazons, 
the Isthmus of Darien, &c. This tree is 
cultivated in many of the West India 
islands, belonging to the French and Spa- 
niards, and formerly in some qf those be- 
longing to the English, but has been neg- 
lected in the latter for many years past. 
THEODOLITE, a mathematical instru- 
ment much u,sed in surveying, for the 
taking of angles, distances, <&c. It is made 
variously, several persons having their seve- 
ral ways of contriving it, each more simple 
and portable, more accurate and expedi- 
tious than others. The common one con- 
sists of a brass circle about a foot diameter, 
having its limb divided into 360 degrees, 
gnd each degree subdivided, either diagoq- 
THE 
ally, or otherwise, into minutes. Sea 
Levei.. 
THEODOSIUS, in biography, a cele- 
brated mathematician, who flourished in the 
times of Cicero and Pompey ; but the time 
and place of his death are unknown. He 
chiefly cidtivatcd that part of geometry 
which relates to the doctrine of the sphere, 
concerning which he published tliree books. 
The first of these contains twenty- two pro- 
positions ; the second twenty-three ; and 
the third fourteen ; all demonstrated in the 
pure geometrical manner of the ancients, 
Ptolemy made great use of these proposi- 
tions, as w'ell as all succeeding writers, 
These books were translated by the Ara- 
bians, out of the original Greek, into their 
own language. From the Arabic, the work 
w'as again translated itito Latin, and printed 
at Venice. But the Arabic version being 
very defective, a more complete edition 
was published in Greek and Latin, at Paris, 
1653, And Vitello acquired reputation by 
translating Theodosius into Latin. This 
author’s works were also commented on 
and illustrated by Clavius, and others ; but 
the edition of Theodosius’s Spherics which 
is now most in use, was translated, and 
published, by our countryman, the learned 
Dr. Barrow, in the year 1676, illustrated 
and demonstrated in a new and concise me- 
thod. By this author’s account, Theodo- 
sius appears not only to be a great master 
in this more difficult part of geometry, but 
the first considerable author of antiquity 
who has written on that subject. 
THEOPHRASTA, in botany, so named 
in honour of the celebrated Grecian philo- 
sopher and botanist Theophrastus Eresius, 
a genus of the Pentaudria Monogynia class 
and order. Natural order of Apocinea*, 
Jussieu. Essential character : corolla bell- 
shaped, with oblong erect spreading seg- 
ments ; fruit one-celled, very large, round- 
ish, many-seeded. There are two species, 
viz. T. americana and T. longifolia, both 
natives of America, 
THEOREM, a speculative proposition, 
demonstrating the properties of any sub- 
ject. Theorems are either universal, which 
extend to any quantity, without restriction 
universally ; as this, that the rectangle of 
the sum, and difference of any two quanti- 
ties, is equal to the difference of their 
squares ; Or particular, which extend only 
to a particular quantity; as this, in an 
equilateral right-fined triangle, each of the 
angles is 60 degree?. Theorems are agajp 
