MAD 
<;ircunistances are determined in all the 
otlier planets, as well as in the sun, by means 
of these maculae. 
The spots, or maculae, observable on the 
moon’s surface, seem to be only cavities or 
large caverns, on which the sun shining 
very obliquely, and touching only their 
upper edge with his light, the deeper places 
remain without light ; but as the sun rises 
higher upon them, they receive more light, 
and the shadow, or dark parts, grow smaller 
and shorter, till the sun comes at last to 
shine directly upon them, and then the 
whole cavity will be illustrated : but the 
dark dusky spots, which continue always 
tlie same, are supposed to proceed from a 
kind of matter or soil which reflects less 
light than that of the other regions. See 
Moon. 
MADDER is a plant, with rough narrow 
leaves, set in form of a star, at the joints of 
the stalk. The root, which is the only part 
made use of, is long, slender, of a red co- 
lour, both on the outside and within, ex- 
cepting a whitish pith, which runs along the 
middle. For cultivating this plant, the 
ground is ploughed deep in autumn, and 
again in March ; and then laid up in ridges, 
eighteen inches asunder, and about a foot 
high. About the beginning of April, they 
open the ground w’here old roots are 
planted, and take off all the side shoots, 
which extend themselves horizontally ; 
tliese they transplant immediately upon the 
new ridges, at about a foot distance, where 
tliey remain two seasons ; and at Michael- 
mas, when the tops of the plants are decay- 
ed, they take up the roots. It is to be ob- 
served, that this method of, planting in 
ridges is only necessary in wet land, and 
that the rows are sometimes planted three 
feet, and the plants in the rows eighteen 
inches asunder. If all the horizontal roots 
are destroyed from time to time, it will 
cause the large, downri.ght roots, to be much 
bigger, in which the goodness of this commo- 
dity chiefly consists. Madder gives out its 
colour, both to water and rectitied spirit : 
the watery tincture is of a dark dull red ; 
the spirituous of a deep bright one. It im- 
parts to woollen cloth, prepared with alum 
and tartar, a very durable, though not a 
very beautiful red dye. As it is the cheapest 
of all the red drugs, that give a durable co- 
lour, it is the principal one commonly made 
use of for ordinary stuffs. Sometimes its dye 
is heightened by the addition of Brazil- 
wood, and sometimes it is employed in con- 
MAD 
junction with the dearer reds, as cochineal j 
for demi-scarlets, and demi-crimsons. 
MADREPORA, in natural history, a 
genus of the Vermes Zoophyta class and 
order. Animal resembling a medusa ; co- 
ral with lamellate star-shaped cavities. This 
is a very numerous genus, comprehending 
about 120 species, separated into distinct 
divisions. A. composed of a single star. 
B. with numerous separate stars, and con- 
tinued gills. C. with numerous united 
stars. D. aggregate, undivided, with dis- 
tinct stars and poriilous tuberculous promi- 
nent undulations. E. branched, with dis- 
tinct stars and tuberculous porulous undula- 
tions. M. verrucaria, star orbicular, flat- 
tish, sessile, with a convex disk full of tubu- 
lar pores and radiate border : it inhabits 
the European, Mediterranean, and Red 
Seas, adhering to marine vegetables and 
the softer zoophytes ; size of a split-pea, 
and appears an intermediate species be- 
tween the madrepore, tubipore, and mille- 
pore; white or yellowish, with aggregate 
tubes on the disk like the florets of a com- 
posite flower, and a flattened striate border 
like the rays of these flowers. A. ananas, 
with angular convex stars, which are con- 
cave on the disk, inhabits the Mediterra- 
nean and South American Sea, and is fre- 
quently found fossile; gibbous, and when 
dissected transversely, resembling a white 
net with hexangular spots, including a 
white ring, and striate between the net 
and ring. See Zoophyta. 
MADREPORITE, a mineral found in 
the valley ofRussback, in Salzburg, and so 
called from its external resemblance to 
madrepore. It is found in large masses, 
is brittle and moderately heavy. Its comi 
ponent parts are. 
Carbonate of lime 93.00 
Carbonate of magnesia.. . . 0.50 
Carbonate of iron 2.25 
Charcoal o.50 
Silica 4.50 
99.75 
Loss 25 
' 100 
MADRIER, in the military art, a long 
and broad plank of M^ood, used for sup- 
porting the earth in mining and carrying on 
a sap, and in making coffeis, caponiers, 
galleries, and for many other uses at a 
siege. Madriers are also used to cover 
the mouths of petards, after they are load- 
