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sum, or of the stones from which plaister of 
Paris is prepared. The spath is directed to 
be calcined with a gentle tire, in a covered 
vessel, till the slight crackling, which happens 
at lirst, has ceased, and the stone has fallen in 
part into powder : the 'whole is then reduced 
into subtle powder, which is passed through a 
fine sieve, and moistened with so much of a 
weak solution of green vitriol as is sufficient 
for making it hold together. Gellert, how- 
ever, finds, that if the stone is of the proper 
kind, which. can he known only by trials, cal- 
cination is not necessary. Scheffer observes, 
that these kind of tests are liable to soften or 
fall asunder in the tire, and that this inconve- 
nience may be remedied by mixing with the 
uncalcined stone somewhat less than equal 
its weight, as eight-ninths, of such as has been 
already u-ed and is penetrated by the scoria 
of the lead, taking only that part of the old test 
which appears of a green-grey colour, and re- 
jecting the red crust on the top. Tests or cu- 
pels made of the spath are said not to require 
so much caution in nealing and heating them 
as the common ones ; it appears, however, 
from Scheffer’s account, that they are less du- 
rable than those made of the ashes of bones, 
though greatly superior to those ot wood- 
ashes. Vegetable ashes, which stand pretty- 
well the testing of silver, can scarcely bear 
any great quantity of gold, this metal requir- 
ing a considerably stronger fire than the other ; 
but bone-ashes answer so effectually, and are 
among us so easily procurable, that it is not 
neediul for the refiner to search for any other 
materials; though those who work off large 
quantities of lead, in order to gain a little sil- 
ver or golrl contained in it, may possibly, in 
places remote from populous cities, avail 
themselves of substances similar to the spath 
above mentioned. 
The test, for its greater security, is fixed 
in the mould in which it was formed ; which 
is sometimes a shallow vessel made ot crucible- 
earth or cast iron ; more commonly an iron 
hoop, with three bars arched downwards 
across the bottom, about two inches deep, 
and of different widths, from three or four 
inches to fifteen or more, according to the 
quantity of metal to be tested at once. The 
ashes or earthy powder, moistened as for 
making cupels, are pressed down in the mould 
so as to completely fill it, or rise a little above 
the sides ; with care to make the mass equally 
solid, and to put in at once, or at least after 
the bottom has been pressed dose, as much 
of the matter as will be sufficient for the 
whole ; for anv additional quantity will not 
unite thoroughly with the rest, but be apt to 
part from it in the fire. The edges are pared 
smooth, and a portion cut out from the middle 
with a bent knife, so as to leave a proper ca- 
vity; which is smoothed by strewing some dry 
powder on the surface, and rolling on it a 
wooden, or rather a glass ball. 
The process of testing is often performed 
in the same manner as that of cupellation : 
but where great quantities of base metal are 
to be worked off from a little gold, recourse 
is had to a more expeditious method, that of 
testing before the bellows. 
An oval test is placed in a cavity, made in 
a hearth of a convenient height, and some 
moistened sand or ashes pressed round it to 
keep it steady : the nose of a bellows is di- 
rected along its surface, in such a manner, 
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that if ashes are sprinkled in the cavity of the 
test, the bellows may blow them completely 
out: some have an iron plate fixed before the 
bellows, to direct the blast downwards. To 
keep the surface of the test from being injured 
in putting in the metal, some cloths or pieces 
of paper are interposed. r l he fuel consists of 
billets of barked oak laid on the sides of the 
test, with others laid crosswise on these: the 
bellows impel the flame on the metal, clear 
the surface of ashes or sparks of coal, hasten 
the scoritication of the lead, and blow off the 
scoria, as fast as it forms, to one end of the test, 
where it runs out through a notch made for 
that purpose. About two-thirds of the sco- 
rified lead may thus be collected ; the rest 
being partly absorbed by the test, and partly 
dissipated by the action of the bellows. Care 
must be taken not to urge the blast too 
strongly, lest some portion of the gold should 
be carried away by the fumes impetuously 
forced off from the lead, and some minute 
particles of it entangled and blown off with the 
scoriae. 
Test-act, a statute 25 Car. II. cap. 2. 
which requires all officers, both civil and mi- 
litary, to take the oaths and test, viz. the sa- 
crament, according to the rites and cere- 
monies of the church of England ; for the 
neglect whereof, a person executing any office, 
mentioned in that statute, forfeits the sum of 
500/. recoverable by action of debt. 
TESTACEA, in the Linnaean system of 
natural history, the third order of vermes. 
This order comprehend sail shell-fish, arrang- 
ed by Linnaeus under thirty-six genera. Shell- 
fish are animals with a soft body, covered by 
or inclosed in a firm, hard, and stony habita- 
tion, composed, according to their three se- 
parate orders, 1. Of many parts which are 
ranged under the name of multivalves; 2. 
Of two parts, which are called bivalves ; 3. 
Of one part or piece only, which we call 
univalves. These parts, pieces, or valves, are 
more or less moveable at the animal’s plea- 
sure. The animals included in these hard 
habitations have most ot them the characters 
of one or other of the genera vermium, and 
might be reduced under the same genera with 
the mollusca : but as these characters are 
few, and the shells very numerous, and dif- 
ferent in their form and structure, it will tend 
more to make this part of natural history easy, 
to arrange the subjects according to the dis- 
tinctions of the shells themselves. I here is 
this farther consideration in favour of this ar- 
rangement, viz. that the animals themselves 
are rarely seen, and never can be preserved 
in cabinets ; whereas the shells make a figure 
in them, and great numbers have been met 
with empty of the animal. The genera classed 
under the several divisions ot this order are, 
A. Multivalves ; chiton, lepas, phloas. El- 
Bivalves; mya, solen, tellina, cardium maetra, 
donax, venus, spondylus, chama, area, ostrea, 
anomia, mytillus, pinna. C. Univalves with 
a regular spire ; argonauta, nautilus, conus, 
cypraea, bulla, voluta, buccinum, strom- 
bus, murex, trochus, turbo, helix, nerita, ha- 
liotis. D. Univalves without a regular spire ; 
patella, dentalium, serpula, teredo, sabella. 
TESTAMENT, in law, a solemn and au- 
thentic act, whereby a person declares his will, 
as to the disposal of his estate, effects, burial, 
&e. See Will. 
TESTATUM, inlaw, a writ in personal 
TES 783 
actions, where, if the defendant cannot be ar- 
rested on a capias, in the county where the 
action is laid, but is returned non est inventus 
by the sheriff, this writ shall be sent into any 
other county, where such person is thought 
to be, or have wherewithal to satisfy the de- 
mand. It is called testatum, because the 
sheriff has, before, testified that the defend- 
ant was not to be found in his bailiwick. 
TESTE, in law, a word generally used in 
the conclusion of every writ, wherein the date 
is contained, and begins with teste meipso. 
See. in case it is an original writ ; or. if only 
judical, then with teste, naming the chief jus- 
tice of the bench whence the writ issues. 
TESTES. See Anatomy. 
TESTUDO, tortoise, a genus of amphibia, 
of the order ’reptiles. 1 he generic character 
is, body defended by a bony covering coated 
by a horny, scaly, or coriaceous integument; 
mouth without distinct or proper teeth, the 
upper mandible closing over the lower. 
In no branch of natural history have more 
errors prevailed than in the attempt to discri- 
minate with precision the several species of 
tortoises; the general similarity being very 
great, and the individuals occasionally vary- 
ing much in size, colours, &c. according to 
the different periods of their growth. On 
the whole, the animals are best distinguished 
by the shape, pattern, and colours ol the shell, 
the form of the head, &c. There are 35 spe- 
cies, of which the most remarkable are: 
Of land and fresh-water tortoises. 
1. Testudo grseca, common tortoise. The 
common or Greek tortoise is supposed to be 
a native of almost all the countries bordering 
on the Mediterranean sea; and is thought to 
be more frequent in Greece than in other re- 
gions. It is found in the scattered European 
islands of the Archipelago, and in Corsica 
and Sardinia. It occurs likewise in many 
parts of Africa. In Greece, according to 
Forskal, “ it forms an article of food ; and 
the inhabitants often swallow the blood recent, 
and eat the eggs boiled, which are about the 
size of those of a pigeon, four or five in num- 
ber, and of a white colour. In September 
the animal hides itself under ground, and again 
emerges in February ; laying its eggs in June, 
in a small hole, which it scratches in some 
sunny spot, out of which, after the first rains 
of September, the young are hatched, which 
are about the size of a walnut. The males 
of this species are said to light often, butting 
at each other with such force as to be heard 
at a considerable distance.” 
The general length of the shell of this spe- 
cies is from six to' eight inches, which latter 
measure it rarely exceeds : the v eight of the 
full-grown animal is about forty-eight ounces. 
The shell is of an oval form, extremely con- 
vex on the upper part, and composed, as in 
most others, of thirteen middle piece-, and 
about twenty-five marginal ones. The head 
is rather small than large; the eyes small and 
black ; the mouth not extending beyond the 
eyes ; the upper part of the head covered 
with somewhat irregular, tough scales, and 
the neck with smaller granulations, so as to 
be flexible at the pleasure of the animal. The 
legs are short, and the feet moderately broad, 
covered with strong ovate scales, and com- 
monly furnished with tour moderately stout 
claws oa each; but this is a circumstance 
