D W A 
leather, is taxed, and, like that leather-tax, 
must be raised: but that caused twelve ad- 
vances on our shoes ; place therefore twelve 
advances more on shoes for the soap- 
tax. These tradesmen use caudles ; twelve 
advances more for the tax on them : and the 
same for every other tax on necessaries. AH 
which, duly considered, might be computed 
at above cent, per cent, on the gross produce 
of the duties ; but though the large duties 
cause some farther advance on all the goods 
they are laid on, charged with profit upon pro- 
fit through every hand they pass, yet as they 
keep not pace with the small duties, and as 
all calculations appear fair when moderate, 
let us abate in the advances, and set them 
down only at 50 per cent. 
Duty, in the military art, is the exercise 
of those functions that "belong to a soldier ; 
with this distinction, that mounting guards 
and the like, where there is no enemy directly 
to be engaged, is called duty; but their 
marching to meet and fight an enemy is call- 
ed going on service. 
DUUMVIRI, in Roman antiquity, a ge- 
neral appellation given to magistrates, com- 
missioners, and officers, where two were join- 
ed together in the same functions. 
Duumviri capitales were the judges in 
criminal causes : from their sentence it was 
lawful to appeal to the people, who only had 
the power of condemning a citizen to death. 
The judges were taken from the body of the 
decuriones ; they had great power and autho- 
rity, were members of the public council, 
and had two lietors to walk before them. 
Duumviri municipales, were two ma- 
gistrates in some cities of the empire, an- 
swering to what the consuls were at Rome: 
they were chosen out of the body of the de- 
curiones ; their office lasted commonly five 
years, upon which account they were fre- 
quently termed quinquinales magistrates. 
Their jurisdiction was of great extent : they 
had officers walking before them, carrying a 
small switch in their hands ; and some of 
them assumed the privilege of having lietors, 
carrying axes and the fasces, or bundles of 
l'ods, before them. 
Duumviri navaues, were the commissa- 
ries of the fleet, first created at the request of 
M. Decius, tribune of the people, in the time 
of the war with the Samnites. The duty of 
their office consisted in giving orders for the 
fitting of ships, and giving their commissions 
to the marine officers, Ac. 
Duumviri sacrorum were magistrates 
created by Tarquinius Superbus, for the per- 
formance of the sacrifice, and keeping of the 
sybil’s books. They were chosen from among 
the patricians, and held their office for life : 
they were exempted from serving in the 
wars, and from the offices imposed on the 
other citizens, and without them the oracles 
of the sybil could not be consulted. 
DWARF, in general, an appellation given 
<o things greatly inferior in size to that which 
is usual in their several kiikls ; thus there are 
dwarfs of the human species, dwarf dogs, 
dwarf trees, Ac. 
Dwarf fruit-trees may be propagated by 
grafting them on a quince-stock, about six 
inches above the ground ; and when the bud 
is shot so far as to have four eyes, it must be 
stopped, to give rise to lateral branches ; for 
which purpose the uppermost eye should al- 
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ways be left outwards. Apple, pear, plum, 
and cherry-trees are thus formed into dwarfs; 
but the summer and autumn pears are found 
to succeed best. 
As to the planting of dwarf trees, they 
should be set at 25 feet square distance, and 
the ground between * sown or planted for 
kitchen use while the trees are young, only 
keeping at some distance from their roots : 
stakes also should be fixed all round them, to 
which the branches may be nailed with list, 
and trimmed in an horizontal direction, and 
prevented from crossing one another. 
DYE, in architecture, any square body, as 
the trunk, or notched part, of a pedestal. See 
Architecture. 
Dye is also used for a cube of stone placed 
under the feet of a statue, and over its pe- 
destal, to raise it, and shew it the more. 
DYEING. Principles of dyeing . — The 
substances commonly employed for clothing 
may be reduced to four; namely wool, silk, 
cotton, and linen. 
Permanent alterations in the colour of cloth 
can only be induced two ways; either by 
producing a chemical change in the cloth, 
or by covering its fibres with some substance 
which possesses the wished-for colour. Re- 
course can seldom or never be had to the 
first method, because it is hardly possible to 
produce a chemical change in the fibres of 
cloth, without spoiling its texture, and ren- 
dering it useless. The dyer, therefore, when 
he wishes to give a new colour to cloth, has 
always recourse to the second method. 
The substances employed for this purpose 
are called colouring matters, or dye-stuffs. 
They are for the most part extracted from 
animal and vegetable substances, and have 
usually the colour which they are to give 
to the cloth. 
Since the particles of colouring matter with 
which cloth, when dyed, is covered, are 
transparent, it follows, that all the light re- 
flected from dyed cloth must be reflected, 
not by the dye-stuff itself, but by the fibres 
of the cloth below the dye stuff. The colour 
therefore does not depend upon the dye 
alone, but also upon the previous colour of 
the cloth. If the cloth is black, it is clear 
that we cannot dye it any other colour what- 
ever ; because as no light in that case is re- 
flected, none can be transmitted, whatever 
dye-stuff we employ. If the cloth was red, 
or blue, or yellow, we could not dye it any 
colour except black; because, as only red, 
or blue, or yellow rays were reflected, no 
other could be transmitted. Hence the im- 
portance of a fine white colour, when cloth 
is to receive bright dyes. It then reflects 
all the ravs in abundance, and therefore any 
colour may lie given, by covering it with a 
dye-stuff which transmits only some parti- 
cular rays. 
If the colouring matters were merely 
spread over the surface of the fibres of cloth 
by the dyer, the colours produced might be 
very bright, but they could not be perma- 
nent; because the colouring matter would 
be very soon rubbed off; and would totally 
disappear whenever the cloth was washed, 
or even barely exposed to the weather. The 
colouring matter then, however perfect a co- 
lour it possesses, is of no value, unless it also 
adheres so firmly to the cloth that none of 
the substances usually applied to cloth, in 
order to clean it, Ac. can displace it. Now 
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this can ohiy happen, when there is a strong 
affinity between the colouring matter and the 
cloth," and when they are actually combined 
together in consequence of that affinity. 
Dyeing then is merely a chemical process, 
and consists in combining a certain colouring 
matter with fibres of cloth. This process 
can in no instance be performed, unless the 
dye-stuff is first reduced to its integrant par- 
ticles; for the attraction of aggregation be- 
tween the particles of dye-stulfs, is too great 
to be overcome by the affinity between them 
and the doth, unless they could be brought 
within much smaller distances than is possible 
while they both remain in a solid form. It 
is necessary, therefore, previously to dissolve 
the colouring matter in some liquid or other, 
which has a weaker affinity for it than the 
cloth has. When the cloth is dipped into 
this solution, the colouring matter, reduced 
by this contrivance toa liquid state, is brought 
within the attracting distance ; the cloth 
therefore acts upon it, and from its stronger 
affinity, takes it from the solvent, and fixes 
it upon itself. By this contrivance too, the 
equality of the colour is in some measure se- 
cured, as every part of the cloth has an op- 
portunity of attracting to itself the proper 
proportion of colouring particles. 
r Ihe facility with which cloth imbibes a 
dye, depends upon two circumstances ; 
namely, the affinity between the cloth and 
the dye-stuff, and the affinity between the 
dye-stuff and its solvent. It is directly as 
the former, and inversely as the latter. 
It is of importance to preserve a due propor- 
tion between these two affinities, as upon lh$t 
proportion much of the accuracy ot dyeing 
depends. If the affinity between the colour- 
ing matter and the cloth is too great, com- 
pared with the affinity between the colouring 
matter and the solvent, the cloth will take 
the dye too rapidly, and it will be scarcely 
possible to prevent its colour from being 
unequal. On the other hand, if the affinity 
between the colouring matter and the solvent 
is too great, compared with that between the 
colouring matter and the cloth, the cloth 
will either not take the colour at all, or it 
will take it very slowly and very faintly. 
Wool has the strongest affinity for almost 
all colouring matters, silk the next strongest, 
cotton a considerably weaker affinity, and 
linen the weakest affinity ot all. In order 
therefore, to dye cotton or linen, the dye 
stuff should in many cases be dissolved in a 
substance for which it has a weaker affinity 
than for the solvent employed in the dyeing 
of wool or silk. Thus we may use oxide ot 
iron dissolved in sulphuric acid, in order to 
dve wool ; but for cotton and linen, it is bet- 
ter to dissolve it in acetous acid. 
Was it possible to procure a sufficient 
number of colouring matters, having a strong 
affinity for cloth, to answer all the purposes 
of dyeing, that art would be exceedingly 
simple and easy. But this is by no means 
the case ; if we except indigo, the dyer is 
scarcely possessed of a dye-stufi which yields 
of itself a good colour, sufficiently permanent 
to deserve the name of a dye. 
This difficulty, which at first sight appears 
insurmountable, has been obviated by a very 
ingenious contrivance. Some substance is 
employed, which has a strong affinity, both 
for the cloth and the colouring matter. This 
substance is previously combined with the 
