COM 
COMMELINA, in botany, so called in 
honour of John and Casper Coramelins,two 
famous Dutch botanists, a genus of the 
Triandria Monogynia class and order. Na- 
tural order of Ensatae. Junci, Jussieu. 
Essential character : corolla six-petalled ; 
nectaries three, cross-shaped, pedicelled. 
There are twelve species, natives of warm 
climates. 
COMMENDAM, in the ecclesiastical 
law, the trust or administration of the reve- 
nues of a benefice, given either to a layman 
to hold, by way of depositum, for six months, 
in order to repairs, &c. or to an ecclesiastic, 
or beneficed person, to perform the pastoral 
duties thereof, till once the benefice is pro- 
vided with a regular incumbent. 
Commendams were formerly a very lau- 
dable institution : for when an elective be- 
nefice became vacant, for which the ordi- 
nary could not, for some reason, immediately 
provide, the care of it was recommended to 
some man of merit, who took upon him the 
direction of it, till the vacancy was filled 
up, but enjoyed none of the profits. 
At length it became a maxim among the 
canonists, that a clerk might hold two bene- 
fices, the one titular, and the other in com- 
mendam : yet still, the commendam was to 
continue only till other provisions were 
made; and afterwards they began to be 
given for a determinate time. 
COMMENSURABLE, among geome- 
tricians, an appellation given to such quan- 
tities as are measured by one and the same 
common measure. 
Commensurable numbers, whether in- 
tegers or fractions, are such as can be mea- 
sured or divided by some other number, 
without any remainder : such are 12 and 18, 
as being measmed by 6 or 3. 
COMMERCE, the exchange of the na- 
tural or artificial productions of a country, 
for tliose of another, cither by barter or by 
representative signs of their value: the 
most general representative of the value of 
other commodities being coin or bulUon, 
the profits of commerce are frequently esti- 
mated by the quantity of money it brings 
into a countiy ; but a very beneficial fo- 
reign trade may be carried on without any 
balance being payable in money, or tire 
balance may be absorbed by payments on 
other accounts. The commerce of Great 
Britain has long been in a very flourishing 
state, and has become of unparalleled ex- 
tent, but the quantity of coin and bidlion in 
tire country has not increased in any consi- 
derable degree. 
COM 
Commerce, in a general point of view, is 
usually distinguished into two kinds, the 
commerce of import and of export ; but 
there is little reason for this distinction, for 
whatever a nation imports, it must have 
paid an equivalent for to the country of 
which it is purchased, and consequently the 
two branches are intimately dependant, and 
could not exist separately for any consi- 
dei'able period. The value obtained in fo- 
reign markets, for the goods or manufac- 
tures which a nation exports, repays the la- 
bour of procuring or manufacturing them, 
with a profit to the master manufacturer 
and to the exporting merchant ; and this va- 
lue being invested in foreign produce which 
on importation aflfords a further profit to 
the merchant, it is evident that the transac- 
tion while it supports individuals, makes a 
real addition to the wealth of the country, 
by the greater value of the returns imported 
beyond that of the goods exported. Com- 
merce, therefore, while it is the means of 
procuring a mutual interchange of conve- 
niencies between distant countries, and of 
extending knowledge and civilization over 
every part of the globe, contributes e^en- 
tially to the strength and influence of the 
countries by which it is encouraged. 
Superficial views on sirbjects of political 
economy have inclined princes and states- 
men to the opinions, that wealth consisted 
principally in gold and silver, and that those 
metals could be brought into a country 
which had no mines oirly by the balance of 
trade, or by exporting to a greater value 
than it imported ; commerce has therefore 
experienced public encouragement, and 
agreeable to the principles on which its va- 
lue has been estimated, the principal regu- 
lations have consisted in restraints upon 
importation, and encouragements to ex- 
portation. The duties and restrictions im- 
posed by one country, either with the 
view of encouraging its trade and manu- 
factures, or for the purpose of rendering 
commerce a source of public revenue, have, 
however, only created similar returns from 
other states, and the commerce of Europe 
has become a complicated system of high 
duties, drawbacks, prohibitions, and boun- 
ties, attended with much unnecessary ex- 
pense, and holding out continual tempta- 
tions to fraud and evasion. The impolicy 
and injustice of many of tlie existing re- 
straints has been shewn by Dr. Adam 
Smith and others, and the prevalence of just 
sentiments of the reciprocal advantages of 
freedom of trade will render future com- 
