WHINMANNIA. 
Division Il.—Troy Weight. 
24grains - -= I1pennyweight -= 24 grains. 
20 pennyweights = lounce - - = 480 “ 
120unces - -= 1 pound - -= 5760 “ 
These are the denominations of troy weight when 
used for weighing gold, silver, and precious 
stones, except diamonds. But troy weight is 
also used by apothecaries in compounding medi- 
cines, and by them the ounce is divided into 
eight drams, and the dram into three scruples, 
so that the latter is equal to twenty grains. For 
scientific purposes, the grain only is used; and 
sets of weights are constructed in decimal pro- 
gression, from 10,000 grains downwards to one 
hundredth of a grain. By comparing the num- 
ber of grains in the avoirdupois and troy pound 
and ounce respectively, it appears that the troy 
pound is less than the avoirdupois, in the pro- 
portion of fourteen to seventeen nearly; but the 
troy ounce is greater than the avoirdupois, in 
the proportion of seventy-nine to seventy-two 
nearly. The carat, used for weighing diamonds, 
is 31 grains. The term, however, when used to 
express the fineness of gold, has a relative mean- 
ing only. Every mass of alloyed gold is supposed 
to be divided into twenty-four equal parts: thus 
the standard for coin is twenty-two carats fine ; 
that is, it consists of twenty-two parts of pure 
gold, and two parts of alloy. What is called the 
new standard, used for watch-cases, &c., is 
eighteen carats fine. 
3. Ancient Wetghts.—It is well known that this 
subject is involved in considerable difficulty. 
The following table gives the estimates of dif- 
ferent authors, in regard to some of the ancient 
weights. 
English Troy Grains. 
8:2 Christiani. 
Attic obolus - - - = ==) 91 Arbuthnot 
Attic drachma - = - - 
Lesser mina - = = mn 5 
I 
———~ —_———_—— 
Greater mina - = = - - 
Medical mina - = = is a 
Talent = 60 mina - S a 2 
ll {I 
for} 
3 
rg 
> 
rs 
io” 
3 cwt. English. 
Grains. 
Old Greek drachm : S = - = 1465 Arb 
Old Greek mina : . 2 o>) = O60 & 
Egyptianmina- - - - - = 8326 “ 
Ptolemaie mina of Cleopatra - = Eee © 
Alexandrian mina of Diosecorides - = 9,992 * 
i. =1-8th Roman 
f rN oz. Chr. 
Roman denarius - rai - - - = 3625 = ee Roman 
A 
Denarius of Nero’ - = = - = 654 Pauc 
415:I Chr. 
Ounce - - - - = - = =~ 437-2 Arb. 
431-2 Pauc. 
Pound = 12 Roman ounces. 
WEINMANNIA. A genus of ornamental, exo- 
tic shrubs of the cunonia family. Two or three 
species have been introduced to British collec- 
tions from Australia, one er two from the Cape 
of Good Hope, and four or five from the tropical 
parts of America; and several more are known. 
Most are evergreens of from 4 to 8 feet in height, 
and carry white flowers in May and June, and 
love a soil of rich mould; but one or two are 
WELL. 659 
deciduous, and one or two red-flowered. Their 
leaves are variously pinnate, trifoliate, elliptic, 
and ovate. The bark of One is used in Peru for 
tanning leather, and is supposed to be employed 
also in adulterating cinchona. 
WELD. See Dyzr’s Weep. 
WELL. A narrow excavation faced round with 
masonry, for commanding a supply of water. It 
may either be shallow and open or deepand cover- 
ed; and may obtain its supplies either by infil- 
tration from the neighbouring surface, or by per- 
colation from comparatively near ponds, streams, 
or reservoirs, or by ascent from deeply-seated and 
far-extending strata in the manner of natural 
springs and Artesian wells; and it therefore may 
afford water of almost any conceivable quality, 
from ditchy to limpid, from brackish to sweet, 
from very soft to very hard, and from saline to 
chalybeate or sulphureous; and it also may 
either be copious or stinted, either steady or fit- 
ful, and either uniform in the quality of its wa- 
ter all the year round or diversified according to 
season and weather. See the articles WarTrr, 
Spring, ARTESIAN WELL, and Pump. 
A district of drift or diluvial clay is the most 
favourable for the forming of wells. This sub- 
stance constitutes the subsoil of a large por- 
tion of the champaign or arable parts of Britain ; 
and though the clay or main bulk of it is im- 
pervious to water, it is both intersected with 
small veins of sand and other porous matter 
through which water percolates, and interspersed 
with numerous small boulders which lie like 
plugs upon pervious strata, and whose removal 
is followed by a permanent oozing or infiltrating 
or uprising of water. In ordinary conditions of 
argillaceous diluvium, a well seldom requires to 
be sunk toa greater depth than from 8 to 16 
feet in order to command a copious and constant 
supply; though when the clay is hard and con- 
tains few or no interspersions and intersections 
of stones and sand, a well of less depth than from 
30 to 50 feet may prove wholly useless. 
A district of stratified rocks, in most places 
where they are but thinly or not at all overlaid 
with diluvium, or where they almost or altogether 
crop here and there out of the surface, is gener- 
ally to the full as favourable for wells as a dis- 
trict of drift; for it often yields a good and plen- 
tiful supply at a depth of only from 6 to 8 feet ; 
but it not unfrequently has the disadvantage of 
letting the water as freely out at one side of the 
well as it lets it in at the other,—so that, in 
some instances, the side of the well on which the 
seams of the rock dip downward require to be 
puddled. 
Districts of deep, unctuous, homogeneous clay 
seldom have water near the surface or within 
the range of the clay itself, but generally afford 
it in great abundance, though sometimes of in- 
different quality, at such considerable or great 
depth as reaches to the formations below the 
clay. The carse lands of Scotland, in general, || 
