TAN 
various modifications of strengtli, and other 
circumstances, will present tiiemselves to 
the operator. He affirms that, in addition 
to the great saving of time and labour in 
this method, the leather, being more com- 
pletely tanned, will weigh heavier, wear 
better, and be less susceptible of moisture, 
than leather tanned in the usual way ; that 
cords, ropes, and cables, made of hemp or 
speartery, impregnated with the tanning 
principle, will support much greater weights 
without breaking, be less liable to be worn 
out by friction, and will run more smoothly 
oil pullies ; insomuch that, in his opinion, 
it v’ill render the use of tar in many cases, 
pai'ticularly in the rigging of ships, unne- 
cessary ; and, lastly, that it may be substi- 
tuted for the preservation of animal food 
instead of salt. The intelligent manufac- 
turer will readily perceive, that this new 
method is grounded on two particular cir- 
cumstances, besides a more scientific ma- 
nagement of the general process than has 
been usual. The first consists in the me- 
thod of determining the presence and quan- 
tity of the tanning principle, by the hydro- 
meter, and the precipitation of glue : the 
second, in applying this principle, in a con- 
centrated state, more early in point of time 
tlian has, perhaps, been hitherto done. Our 
tanners, after the common previons pro- 
cesses, and unhairing by acids, by lime, or 
by piling the hides that they may heat and 
begin to putrify, apply the solution of tan, 
which they call ouze, in a great n-nmber of 
pits in the tan-yard. They begin with the 
weakest solution, which has been \ ised, and 
is of a lighter colour than the other; and 
they pass the hidps, according to tlheir judg- 
ment andexperience, into ouzes 'which are 
sti onger and stronger ; until at las t, in cer- 
tain cases, the hides come to be b nried, for 
a certain time, in a solid mass c if tan, or 
oak-bark. The oak-bark itself, i; i the pits, 
is not only the source from which the water 
extracts the tanning principle, b ut seems, 
likewise, in some measure, durin 5 the last 
stages of the process, to operate jnechani- 
caily, by keeping the surfaces of the hides 
from touching each other. 
TANTALITE, in mineralogy, a; metallic 
fossil of an iron black colour on the external 
surface, but internally between blu ish-grey, 
and iron-black. It occurs imbeilded, in 
masses of the size of a hazel nut, wh ich hav e 
a tendency to the octahedral form. Exter- 
nally it is smooth and glimmering ; inter- 
nally it is shining, and its lustre metallic. 
Specific gravity is 7.93. Its constituent 
TAN 
parts are tantalium, irbn, and manganese. 
It is found imbedded in quartz, in Sweden ; 
its name is derived from the new metal 
denominated Tantalium, which see. 
TANTALIUM, a metal discovered by 
M. Ekeberg,in the mineral just mentioned ; 
and in another named Ytrotantalite. From 
each he extracted by means of the fixed 
alkalies a white powder, which he ascer- 
tained to be the oxide of a peculiar metal ; 
to this he gave the name of tantalium. 
When this oxide is powerfully heated with 
charcoal, it yields a button moderately 
hard, which, externally, has a metallic 
lustre, but internally it is blacA, and with- 
out any degree of brilliancy. The acids 
will reduce it again to an oxide, but they 
will not dissolve it. It melts before thh- 
blow-pipe with borax, or pJiosphate of soda, 
but gives no colour to either of them. Its 
specific gravity is about 6.5. 
TANTALUS, the il/is, in natural history, 
a genus of birds of f,ie order Grallm. Ge- 
neric character : bill long ; thick at the 
base, incurvated ,• face naked, and some- 
times all the hea'i ; tongue broad and short ; 
nostrils linear and oval ; four thes, con- 
nected by a membrane at the base. There 
are ninefaen species, of which we shall 
notice fne following. T. loculator, the 
wood itjis, is of the size of a goose, and the 
length of three feet, and is found in Caro- 
lina, and in many countries of South Arae- 
ricii, haunting, particularly, those low tracts 
which are inundated during summer. These 
birds subsist on reptiles and fish, have 
little sagacity, and are often seen in cypress 
trees of extraordinary height, with their 
heavy bills reposing on their breasts. They 
are in use for the table, though far from 
being excellent. 
T. ruber, or the scarlet ibis, is found in 
America, and the neighbouring islands. Its 
plumage is of a most ardent scarlet, and it 
is one of the most beautiful birds of the ge- 
nus. It subsists on insects, and the ova of 
fishes, for which, on the ebbing of the tide, 
it frequents the shores. It perches in 
trees, but lays its eggs on the ground, l^e 
old birds and the young keep in distinct 
flocks. They do not attain the full lustre 
and glow of plumage till their third year ; 
and in sickness and confinement lose almost 
all their brilliancy. 
T. ibis, or the Egyptian ibis, is more 
than three feet long, and as large as a 
stork. On the retreating of the Nile, it is 
found in Lower Egypt in great numbers, 
subsisting on insects and frogs. It perches 
