594 
THE TROPICAL AGRICULTURIST, 
March i, 1898. 
cid. Although up to this no blood has been used, 
he extract is less highly coloured than that ob- 
ained by the immediately preceding method. 
To decolorise still further, proceed to coagulate 
with blood, and decant, filter and concentrate as 
before. The liquor thus obtained is of the colour 
of pale honey, and is so limpid that it enters the 
thickest hide rapidly and converts it into leather 
in the course of a few days. 
i. Villon’s Process. 
For this process a special, but very simple appa- 
ratus is required. A large square copper or brass 
vessel about 7 feet high and H feet side, divided by 
the removable cross-plates into three compartments, 
a false bottom of very stout wire gauze, which can be 
pulled up by means of four rods when the vessel 
is to be emptied. 
Each of the plates (E.P., GH) has 250 circular 
performations about two-fifths of an inch in diameter. 
TT is a tube of about 3 inches bore and about 
6 feet long, which passes through the centre of both 
moveable plates and is held in place by the lower 
plate at such a height that its lower extremity is 
only a few inches above the bottom of the vessel, 
while the upper extremity projects a little beyond 
the upper plate. 
PPP is a pipe through which steam is introduced 
into the lowest compartment of the vessel, while 
tj is a tap through which fresh water can be let into 
the same compartment, and t^ another tap through 
which that compartment can be emptied. 
The height of the lowest compartment is about 23 
nches, that of the highest about G inches. 
To set the apparatus in operation, the middle com- 
partment is filled tight with the chips or shavings of 
which the tannin is to be extracted, and distilled 
water is introduced into the lowest compartment up 
to a few inches below the upper level of the pipe PP. 
Steam is now let in. The water soon boils and, under 
compression of the steam in the space above it, is 
forced up through the central tube TT into the highest 
compartment, whence it enters the middle one below 
and finds its way back into the lowest compartment 
carrying away with it in solution extractive matter 
from the chips or shavings. In this way a conti- 
nuous circulation of the water is set up, and in 
about 6 hours the extraction is complete. 
By working a battery of several such vessels so 
connected with one another that the extract from 
the first, when the shavings have been sufficiently 
e.xhausted, can be turned on, through a tube furnished 
with a tap, from the tube KK into the uppermost 
chamber of the second vessel, and so on up to the 
last vessel, a liquor of great strength is at once 
obtained which requires very little concentration. 
The advantages of this system are: (1) that the 
strongest possible extract is obtained with a given 
limited quantity of water,* so that the labour and 
expense of concentration is ver.y appreciably dimi- 
nished; (2) that the liquor is light-coloured and fairly 
clear, and hardly requires special bleaching if the 
wood used does not contain a dark dye; (3) that 
it exhausts the wood of all its tannin; and (4) that 
the extract contains less gallic acid and gallate of 
tannin than that obtained by any other process. More- 
over, as no chemicals are required and the entire 
process is within the comprehension of the lowest 
intelligence, the method is specially adapted for 
employment in our Indian forests, however remote. 
It would suit cutch manufacture perfectly. 
The remark may hero be made that there seems 
no reason why the vessel as well as the partitions 
should not be of wood, which would not only be 
much cheaper than metal, but also retain heat better 
and have no injurious effect on the tannin. Even 
the wire gauze sieve could bo replaced by a wooden 
trellia frame covered over first wiih bamboo matting 
» When chestnut wood, which contains 5 to G per- 
cent of its weight of tannin, is used, the liquor obtained 
bv decoction in a single vessel marks 5°-G® Baume 
p,pd gontaiug 5 per cent of tannin, 
and then with stout cotton drill, which would filter 
as effectively as the finest wire-gauze. 
5. Luc’s Process. 
M. Luc owns several large tanneries, one of which 
is at Nancy. He employs only oak, not only because 
oak liquor produces firmer leather and is more easily 
rendered lighter coloured than chestnut extract, but 
also because the tree is more widely distributed in 
France and therefore more easily procured. He 
uses only root-stocks, butt-ends and branches, i.c., 
such pieces as are useless for timber; but he rejects 
everything that measures less than 4 inches in diameter 
at the small end. His wood costs him about 22^ shillings 
per 100 stacked cnbic feet delivered at the tannery. 
At first M. Luc used to have the wood barked on 
the express advice of the chemist who invented the 
system employed by him, but he found the cost of 
barking very heavy and gave it up. Since doing so, 
the liquor he obtains is richer in tannin and is more 
easily made light coloured. 
The wood is reduced to shavings less than one- 
twelfth of an inch thick. The decoction is effected 
in wooden vats, each taking nearly 6,200 lb. of chips, 
with boiling water which is kept in constant cir- 
culations. The vats are connected together so that 
the liquor from one passes into another holding 
fresher chips. When the liquor marks 25° Baume 
it is run into a large wooden barrel containing a 
serpentine tube, through which cold water is con- 
stantly running. As soon as the temperature of the 
liquor has fallen to 30° to 35°U., blood is added 
with a little sulphuric acid. The temperature is then 
raised to 60° — G.5°C. to coagulate the albumen of the 
blood. By this clarification the density of the liquor 
is reduced to 2° Baume. Concentration is now effected 
by the ordinary pneumatic process until the areo- 
meter marks 20° to 2c°. 
This extract is not used by itself, but is only 
added gradually to strengthen the ordinary tan liquor 
in which the hides are soaking. 
The gallon weighs 12 lb. and sells at 23.Jd. Even 
at this rate the profits are very high, and M. Luc 
is driving a roaring business. 
The exhausted chips are used as fuel for generating 
steam for the machinery and other purpose, special 
grates being used which do away with the necessity 
of previously drying the chips. 
III. Concluding Remarks. 
In India we could employ not only wood, but 
also barks for the preparation of tanning extracts. 
One of the functions of the Forest School at Dehra 
Dun should be to anylyse for tannins the bark and 
wood of all our likely species. The system of effect- 
ing analyses with the help of students, which was 
in force during Dr. Warth’s tenure of the Instruc- 
torsbip of Natural Sciences, should be resumed, 
especially as there is now an Instructor to spare 
during the open season. To assist the Instructor 
only the more intelligent students, who have shown 
a bent for chemistry, would be selected. 
It will be remembered that Captain Wood, late 
Conservator of Forests of the Oudh Circle, made a 
solid extract of sal bark which he tried to get^ 
accepted at Cawnpore and by tanners in England,^ 
The experiment was not successful owing, no doubt, 
to the extract containing colouring matters and other 
impurities, and probably also to being prepared at 
too high a temperature ; but the venture certainly 
deserves being repeated, not so much in order to 
make the preparation of the extract a departmental 
business, as to attract and invite to it private en- 
terprise . — Indian Forester, 
The Codlin-Motii.— These orchardists who have 
but few Apples this year will have their compensation 
next year in the greatly lessened numbers of the 
Codlin-moth. It has been remarked that in orchards 
which had few Apples in any one year, the fruits 
were not greatly injured the following year, even 
when no measures were taken to prevent an attack. 
This was doubtless owing to the moth finding few 
or no fruit in which to develop the maggot,— 6rar« 
deners’ Chronicle, 
