MER 
reign languages, or at least as many of them 
as he can attain to; these may be reduced 
to four, viz. tlie Spanish, which is used not 
only in Spain, but on the coast of Africa, 
from the Canaries to the Cape of Good 
Hope : the Italian, which is understood on 
all the coasts of the Mediterranean, and in 
many parts of the Levant : the German, 
which is understood in almost all the north- 
ern countries ; and the French, which is 
now become almost universally current. 
18. He ought to be acquainted with the 
consular jurisdiction, with the laws, cus- 
toms, and usages of the different countries 
he does or may trade to ; and in general all 
the ordinances and regulations, both at 
home and abroad, that have any relation to 
commerce. 19. Tliough it is not necessary 
for a merchant to be very learned, it is pro- 
per that lie should know something of his- 
tory, particularly that of his own country, 
geography, hydrography, or the science of 
navigation, and that he is acquainted with 
the discoveries of the countries in which 
trade is established, in what manner it is 
settled, of the companies formed to support 
those establishments, and of the colonies 
they have sent out. 
All these branches of knowledge are of 
great service to a merchant who carries on 
an extensive commerce ; but if his trade 
and his views are more limited, his learning 
and knowledge may be so too : but a ma- 
terial requisite for forming a merchant is, 
his having on all occasions a strict regard to 
truth, and his avoiding fraud and deceit, as 
corroding cankers that must inevitably de- 
stroy his reputation and fortune. 
Trade is a thing of so universal a nature, 
that it is impossible for the laws of Eng- 
land, or of any other nation, to determine 
all the affairs relating to it; therefore all 
nations, as well as Great Britain, shew a 
particular regiffd to the law merchant, 
which is a law made by the merchants 
among themselves : however, merchants 
and other strangers are subject to the laws 
of the country in which they reside. Fo- 
reign merchants are to sell their merchan- 
dize at the port where they land, in gross, 
and not by retail ; and they are allowed to 
be paid in gold or silver bullion, in foreign 
coin or jewels, which may be exported. If 
a difference arises between the King and 
any foreign state, the merchants of that 
state are 'allowed six months’ time to sell 
their effects and leave the kingdom, during 
which time they are to remain free and un- 
molested in their persons and goods. 
MER 
Merchant. The law of merchants is 
part of the common law of England. See 
Insurance, Bii-ls of Exchange. 
MERCURIALIS, in botany, mercunj, 
a genus of the Dioecia Enneandria class 
and order. Natural order of Tricocc®. 
Euphorbiae, Jussieu. Essential character; 
male, calyx three-parted ; corolla none ; sta- 
mina nine or twelve; anthers globular, 
twin : female, calyx three-parted ; corolla 
none ; styles two ; capsule dicoccous, two- 
celled, one seeded. 'There are six species. 
MERCURY, a metal which has long 
been distinguished, as the only one that re- 
tains its fluidity at the common tempera- 
ture of the atmosphere. The late discove- 
ries of Mr. Davy have, however, produced 
two others which possess this property : 
these will be noticed in their places : see 
SoDAiuM, and Potassium ; see also Al- 
kali. When the temperature is reduced 
to about 40“ below zero of Fahrenheit, it 
assumes a solid form : this however is a de- 
gree of cold that never occurs but in high 
northern latitudes, and in this country mer- 
cury can only be exhibited in a solid state 
by artificial means : see Cold. When con- 
gealed, its specific gravity is so much in- 
creased, that it sinks to the bottom of the 
fluid mass. It has been increased from 
13.5 to 15.6. At about 600“ of Fahrenheit, 
it boils and is changed into vapour, and this 
method is taken to purify it from the ad- 
mixture of other metals. When very pure, 
mercury is not oxydized at the common 
temperature of the atmosphere, but may be 
converted into an oxide by boiling. It is 
dissolved by hot sulphuric acid, and forms 
a white salt, which, being washed with 
boiling water, produces a yellow substance 
called turbith mineral. It may likewise be 
dissolved by nitric acid with and without 
heat; but the mercury is more highly 
charged with oxygen in the former case 
tlian in the latter. It may be united to the 
muriatic acid by a double elective affinity ; 
thus when sulphate of mercury and muriate 
of soda, both dry, are mixed and exposed 
to heat, a combination of oxide of mercury 
and muriatic acid is obtained by sublima- 
tion : this is called in the shops “ corro- 
sive sublimate.” “ Calomel ” is compound- 
ed of tlie same substances, but with a larger 
proportion of mercury. Corrosive muriate 
of mercury is in the form of a white com- 
pact mass, tending to a crystalline arrange- 
ment : it is soluble in about twenty parts 
of water, at the temperaturnof 60°, and in 
two parts of boiling water. In alcohol 
