The large felspar and kaolin mill, made by Mr. Hall, for Sèvres, has a
flat bed of hornstone, in one block, laid at the bottom of a great tub,
hooped strongly with iron. In most of the English potteries, however,
that bed consists of several flat pieces of chert or hornstone, laid
level with each other. There is, as usual, a spigot and faucet at the
side, for drawing off the liquid paste. The whole system of the
mechanism is very substantial, and is supported by wooden beams.
The following is the manner of turning the upper blocks. In _fig._ 900.
the main horizontal shaft P bears at one of its extremities a toothed
wheel, usually mounted upon the periphery of the great water-wheel
(_fig._ 908. shows this toothed wheel by a dotted line) at its other
end; P carries the fixed portion _p_ of a coupling-box, similar to the
one just described as belonging to the little mill. On the prolongation
of P, there is a second shaft P´, which bears the movable portion of
that box, and an upright bevel wheel P´´. Lastly, in _figs._ 900. and
908. there is shown the vertical shaft Q, which carries at its upper end
a large horizontal cast-iron wheel Q´, not seen in this view, because it
is sunk within the upper surface of the turning hornstone, like the
clamp _d_, _f_, in _fig._ 902. At the lower end of the shaft Q, there is
the bevel wheel Q´´, which receives motion from the wheel P´´, _fig._
900.
The shaft P always revolves with the water-wheel; but transmits its
motion to the shaft P´ only when the latter is thrown into geer with
the coupling-box _p´_, by means of its forked lever. Then the bevel
wheel P´ turns round with the shaft P´, and communicates its rotation to
the bevel wheel Q´´, which transmits it to the shaft Q, and to the large
cast-iron wheel, which is sunk into the upper surface of the revolving
hornstone.
[Illustration: 908]
The shaft Q is supported and centred by a simple and solid adjustment;
at its lower part, it rests in a step R, which is supported upon a
cast-iron arch Q´, seen in profile in _fig._ 900.; its base is solidly
fixed by four strong bolts. Four set screws above R, _fig._ 900., serve
to set the shaft Q truly perpendicular: thus supported, and held
securely at its lower end, in the step at R, _figs._ 900. and 908., it
is embraced near the upper end by a brass bush or collar, composed of
two pieces, which may be drawn closer together by means of a screw. This
collar is set into the summit of a great truncated cone of cast-iron,
which rises within the tub through two-thirds of the thickness of the
hornstone bed; having its base firmly fixed by bolts to the bottom of
the tub, and having a brass collet to secure its top. The iron cone is
cased in wood. When all these pieces are well adjusted and properly
screwed up, the shaft Q revolves without the least vacillation, and
carries round with it the large iron wheel Q´, cast in one piece, and
which consists of an outer rim, three arms or radii, and a strong
central nave, made fast by a key to the top of the shaft Q, and resting
upon a shoulder nicely turned to receive it. Upon each of the three
arms, there are adjusted, with bolts, three upright substantial bars of
oak, which descend vertically through the body of the revolving mill to
within a small distance of the bed-stone; and upon each of the three
arcs of that wheel-ring, comprised between its three strong arms, there
are adjusted, in like manner, five similar uprights, which fit into
hollows cut in the periphery of the moving stone. They ought to be cut
to a level at their lower part, to suit the slope of the bottom of the
tub _o_, _figs._ 900. and 908., so as to glide past it pretty closely,
without touching.
The speed of this large mill is eight revolutions in the minute. The
turning hornstone describes a mean circumference of 141-1/3 inches (its
diameter being 45 inches), and of course moves through about 100 feet
per second. The tub O, is 52 inches wide at bottom, 56 at the surface of
the sleeper block (which is 16 inches thick), and 64 at top, inside
measure. It sometimes happens that the millstone throws the pasty
mixture out of the vessel, though its top is 6 inches under the lip of
the tub _o_; an inconvenience which can be obviated only by making the
pap a little thicker; that, is by allowing only from 25 to 30 per cent.
of water; then its density becomes nearly equal to 2·00, while that of
the millstones themselves is only 2·7; whence, supposing them to weigh
only 2 cwt., there would remain an effective weight of less than 1/2
cwt. for pressing upon the bottom and grinding the granular particles.
This weight appears to be somewhat too small to do much work in a short
time; and therefore it would be better to increase the quantity of
water, and put covers of some convenient form over the tubs. It is
estimated that this mill will grind nearly 5 cwt. of hard kaolin or
felspar gravel, in 24 hours, into a proper pap.
To the preceding methodical account of the porcelain manufacture, I
shall now subjoin some practical details relative to certain styles of
work, with comparisons between the methods pursued in this country and
upon the Continent, but chiefly by our jealous rivals the French.
The blue printed ware of England has been hitherto a hopeless object of
emulation in France. M. Alexandre Brongniart, membre de l’Institut, and
director of the _Manufacture Royal de Sèvres_, characterizes the French
imitations of the _Fayence fine, ou Anglaise_, in the following terms:
“Les défauts de cette poterie, qui tiennent à sa nature, sont de ne
pouvoir aller sur le feu pour les usages domestiques, et d’avoir un
vernis tendre, qui se laisse aisément entamer par les instruments
d’acier et de fer. Mais lorsque cette poterie est mal fabriquée, ou
fabriquée avec une économie mal entendue, ses défauts deviennent bien
plus graves; son vernis jaunâtre et tendre tressaille souvent; il se
laisse entamer ou user avec la plus grande facilité par les instruments
de fer, ou par l’usage ordinaire. Les fissures que ce tressaillement ou
ces rayures ouvrent dans le vernis permettent aux matières grasses de
pénétrer dans le biscuit, que dans les poteries affectées de ce défaut,
a presque toujours une texture lâche; les pièces se salissent,
s’empuantissent, et se brisent même avec la plus grande facilité.”[42]
[42] Dict. Technologique, tom. xvii., article Poteries, p. 253.
What a glaze, to be scratched or grooved with soft iron; to fly off in
scales, so as to let grease soak into the biscuit or body of the ware;
to become foul, stink, and break with the utmost ease! The refuse
crockery of the coarsest pottery works in the United Kingdom would
hardly deserve such censure.
In the minutes of evidence of the _Enquête Ministérielle_, published in
1835, MM. de Saint Cricq and Lebeuf, large manufacturers of pottery-ware
at Creil and Montereau, give a very gratifying account of the English
stoneware manufacture. They declare that the English possess magnificent
mines of potter’s clay, many leagues in extent; while those of the
French are mere patches or _pots_. Besides, England, they say, having
upwards of 200 potteries, can constantly employ a great many public
flint-mills, and thereby obtain that indispensable material of the best
quality, and at the lowest rate. “The mill erected by M. Brongniart, at
Sèvres, does its work at twice the price of the English mills. The fuel
costs in England one-fourth of what it does in France. The expense of a
kiln-round, in the latter country, is 200 francs; while in the former it
is not more than 60.” After a two-months tour among the English
potteries, these gentlemen made the following additional observations to
their first official statement:----
“The clay, which goes by water carriage from the counties of Devon and
Dorset, into Staffordshire, to supply more than 200 potteries, clustered
together, is delivered to them at a cost of 4 francs (3_s._ 2_d._) the
100 kilogrammes (2 cwt.); at Creil, it costs 4_f._ 50_c._, and at
Montereau, only 2_f._ 40_c._ There appears, therefore, to be no
essential difference in the price of the clay; but the quality of the
English is much superior, being incontestably whiter, purer, more
homogeneous, and not turning red at a high heat, like the French.” The
grinding of the flints costs the English potter 4-1/2_d._ per 100
kilos., and the French 6_d._; but as that of the latter is in general
ground dry, it is a coarser article. The kaolin, or china clay, is
imported from Cornwall for the use of many French potteries; but the
transport of merchandise is so ill managed in France, that while 2 cwts.
cost in Staffordshire only 8_f._ 75_c._ (about 7_s._ 1_d._), they cost
12_f._ at Creil, and 13f. 50_c._ at Montereau. The white lead and
massicot, so much employed for glazes, are 62 per cent. dearer to the
French potters than the English. As no French mill has succeeded in
making unsized paper fit for printing upon stoneware, our potters are
under the necessity of fetching it from England; and, under favour of
our own custom-house, are allowed to import it at a duty of 165_f._ per
100 kilogrammes, or about 8_d._ per pound English. No large stock of
materials need be kept by the English, because every article may be had
when wanted from its appropriate wholesale dealers; but the case is
quite different with the French, whose stocks, even in small works, can
never safely be less in value than 150,000_f._ or 200,000_f._;
constituting a loss to them, in interest upon their capital, of from
7,500_f._ to 10,000_f._ per annum. The capital sunk in buildings is far
less in England than in France, in consequence of the different styles
of erecting stoneware factories in the two countries. M. de Saint Cricq
informs us, that Mr. Clewes, of Shelton, rents his works for 10,000_f._
(380_l._) per annum; while the similar ones of Creil and Montereau, in
France, have cost each a capital outlay of from 500,000_f._ to
600,000_f._, and in which the products are not more than one half of Mr.
Clewes’. “This forms a balance against us,” says M. St. C., “of about
20,000_f._ per annum; or nearly 800_l._ sterling. Finally, we have the
most formidable rival to our potteries in the extreme dexterity of the
English artisans. An enormous fabrication permits the manufacturers to
employ the same workmen during the whole year upon the same piece; thus
I have seen at Shelton a furnisher, for sixpence, turn off 100 pieces,
which cost at Creil and Montereau 30 sous (1_s._ 2-1/2_d._); yet the
English workman earns 18_f._ 75_c._ a week, while the French never earns
more than 15_f._ I have likewise seen an English moulder expert enough
to make 25 waterpots a day, which, at the rate of 2_d._ a piece, bring
him 4_s._ 2_d._ of daily wages; while the French moulder, at daily wages
also of 4_s._ 2_d._, turns out of his hands only 7, or at most 8 pots.
In regard to hollow wares, the English may be fairly allowed to have an
advantage over us, in the cost of labour, of 100 per cent.; which they
derive from the circumstance, that there are in Staffordshire 60,000
operatives, men, women, and children, entirely dedicated to the
stoneware manufacture; concentrating all their energies within a space
of 10 square leagues. Hence a most auspicious choice of good practical
potters, which cannot be found in France.”
M. Saint Amans, a French gentleman, who spent some years in
Staffordshire, and has lately erected a large pottery in France, says
the English surpass all other nations in manufacturing a peculiar
stoneware, remarkable for its lightness, strength, and elegance; as also
in printing blue figures upon it of every tint, equal to that of the
Chinese, by processes of singular facility and promptitude. After the
biscuit is taken out of the kiln, the fresh impression of the engraving
is transferred to it from thin unsized paper, previously immersed in
strong soap water; the ink for this purpose being a compound of
arseniate of cobalt with a flux, ground up with properly boiled linseed
oil. The copper-plates are formed by the graving tool with deeper or
shallower lines according to the variable depth of shades in the design.
The cobalt pigment, on melting, spreads so as to give the soft effect of
water-colour drawing. The paper being still moist, is readily applied to
the slightly rough and adhesive surface of the biscuit, and may be
rubbed on more closely by a dossil of flannel. The piece is then dipped
in a tub of water, whereby the paper gets soft, and may be easily
removed, leaving upon the pottery the pigment of the engraved
impression. After being gently dried, the piece is dipped into the glaze
mixture, and put into the enamel oven.
_Composition of the Earthy Mixtures._
The basis of the English stoneware is, as formerly stated, a bluish
clay, brought from Dorsetshire and Devonshire, which lies at the depth
of from 25 to 30 feet beneath the surface. It is composed of about 24
parts of alumina, and 76 of silica, with some other ingredients in very
small proportions. This clay is very refractory in high heats, a
property which, joined to its whiteness when burned, renders it
peculiarly valuable for pottery. It is also the basis of all the yellow
biscuit-ware called _cream colour_, and in general of what is called the
_printing body_; as also for the semi-vitrified porcelain of Wedgewood’s
invention, and of the tender porcelain.
The constituents of the stoneware are, that clay, the powder of calcined
flints, and of the decomposed felspar called Cornish stone. The
proportions are varied by the different manufacturers. The following are
those generally adopted in one of the principal establishments of
Staffordshire:--
For _cream colour_, Silex or ground flints 20 parts.
Clay 100
Cornish stone 2
_Composition of the Paste for receiving the Printing Body under the
Glaze._
For this purpose the proportions of the flint and the felspar must be
increased. The substances are mixed separately with water into the
consistence of a thick cream, which weighs per pint, for the flints 32
ounces, and for the Cornish stone 28. The china clay of Cornwall is
added to the same mixture of flint and felspar, when a finer pottery or
porcelain is required. That clay cream weighs 24 ounces per pint. These
24 ounces in weight are reduced to one-third of their bulk by
evaporation. The pint of dry Cornish clay weighs 17 ounces, and in its
first pasty state 24, as just stated. The dry flint powder weighs 14-1/2
ounces per pint; which when made into a cream weighs 32 ounces. To 40
measures of Devonshire clay-cream there are added,
13 measures of flint liquor.
12 -- Cornish clay ditto.
1 -- Cornish stone ditto.
The whole are well mixed by proper agitation, half dried in the
_troughs_ of the slip-kiln, and then subjected to the machine for
cutting up the clay into junks. The above paste, when baked, is very
white, hard, sonorous, and susceptible of receiving all sorts of
impressions from the paper engravings. When the silica is mixed with the
alumina in the above proportions, it forms a compact ware, and the
impression remains fixed between the biscuit and the glaze, without
communicating to either any portion of the tint of the metallic colour
employed in the engraver’s press. The felspar gives strength to the
biscuit, and renders it sonorous after being baked; while the china clay
has the double advantage of imparting an agreeable whiteness and great
closeness of grain.
PRECIPITATE, is any matter separated in minute particles from the bosom
of a fluid, which subsides to the bottom of the vessel in a pulverulent
form.
PRECIPITATION, is the actual subsidence of a precipitate.
PRESS, HYDRAULIC. Though the explanation of the principles of this
powerful machine belongs to a work upon mechanical engineering, rather
than to one upon manufactures, yet as it is often referred to in this
volume, a brief description of it cannot be unacceptable to many of my
readers.
[Illustration: 909]
The framing consists of two stout cast-iron plates _a_, _b_, which are
strengthened by projecting ribs, not seen in the section, _fig._ 909.
The top or crown plate _b_, and the base-plate _a_, _a_, are bound most
firmly together by 4 cylinders of the best wrought iron, _c_, _c_, which
pass up through holes near the ends of the said plates, and are fast
wedged in them. The flat pieces _e_, _e_, are screwed to the ends of the
crown and base plates, so as to bind the columns laterally. _f_, is the
hollow cylinder of the press, which, as well as the ram _g_, is made of
cast iron. The upper part of the cavity of the cylinder is cast narrow,
but is truly and smoothly rounded at the boring-mill, so as to fit
pretty closely round a well-turned ram or piston; the under part of it
is left somewhat wider in the casting. A stout cup of leather,
perforated in the middle, is put upon the ram, and serves as a valve to
render the neck of the cylinder perfectly water-tight, by filling up the
space between it and the ram; and since the mouth of the cup is turned
downwards, the greater the pressure of water upwards, the more forcibly
are the edges of the leather valve pressed against the inside of the
cylinder, and the tighter does the joint become. This was Bramah’s
beautiful invention.
Upon the top of the ram, the press-plate or table, strengthened with
projecting ridges, rests, which is commonly called the follower, because
it follows the ram closely in its descent. This plate has a half-round
hole at each of its four corners, corresponding to the shape of the four
iron columns along which it glides in its up-and-down motions of
compression and relaxation.
[Illustration: 910 911 912]
_k_, _k_, _figs._ 909. and 910., is the framing of a force pump with a
narrow barrel; _i_ is the well for containing water to supply the pump.
To spare room in the engraving, the pump is set close to the press, but
it may be removed to any convenient distance by lengthening the
water-pipe _u_, which connects the discharge of the force pump with the
inside of the cylinder of the press. _Fig._ 911. is a section of the
pump and its valves. The pump _m_, is of bronze; the suction-pipe _n_,
has a conical valve with a long tail; the solid piston or plunger _p_,
is smaller than the barrel in which it plays, and passes at its top
through a stuffing-box _q_; _r_ is the pressure-valve, _s_ is the
safety-valve, which, in _fig._ 910., is seen to be loaded with a
weighted lever; _t_ is the discharge-valve, for letting the water
escape, from the cylinder beneath the ram, back into the well. See the
winding passages in _fig._ 912. _u_ is the tube which conveys the water
from the pump into the press-cylinder. In _fig._ 910. two centres of
motion for the pump-lever are shown. By shifting the bolt into the
centre nearest the pump-rod, the mechanical advantage of the workman may
be doubled. Two pumps are generally mounted in one frame for one
hydraulic press; the larger to give a rapid motion to the ram at the
beginning, when the resistance is small; the smaller to give a slower
but more powerful impulsion, when the resistance is much increased. A
pressure of 500 tons may be obtained from a well-made hydraulic press
with a ten-inch ram, and a two and a one inch set of pumps. See STEARINE
PRESS.
PRINCE’S METAL, or Prince Rupert’s metal, is a modification of brass.
PRINTING INK. (_Encre d’imprimerie_, Fr.; _Buchdruckerfarbe_, Germ.)
After reviewing the different prescriptions given by Moxon, Breton,
Papillon, Lewis, those in Nicholson’s and the Messrs. Aikins’
Dictionaries, in Rees’ Cyclopædia, and in the French Printer’s Manual,
Mr. Savage[43] says, that the Encyclopædia Britannica is the only work,
to his knowledge, which has given a recipe by which a printing ink might
be made, that could be used, though it would be of inferior quality, as
acknowledged by the editor; for it specifies neither the qualities of
the materials, nor their due proportions. The fine black ink made by Mr.
Savage, has, he informs us, been pronounced by some of our first
printers to be unrivalled; and has procured for him the large medal from
the Society for the Encouragement of Arts.
[43] In his work on the Preparation of Printing Ink; 8vo, London,
1832.
1. _Linseed oil._--Mr. S. says, that the linseed oil, however long
boiled, unless set fire to, cannot be brought into a proper state for
forming printing ink; and that the flame may be most readily
extinguished by the application of a pretty tight tin cover to the top
of the boiler, which should never be more than half full. The French
prefer nut oil to linseed; but if the latter be old, it is fully as
good, and much cheaper, in this country at least.
2. _Black rosin_ is an important article in the composition of good ink;
as by melting it in the oil, when that ingredient is sufficiently
boiled and burnt, the two combine, and form a compound approximating to
a natural balsam, like that of Canada, which is itself one of the best
varnishes that can be used for printing ink.
3. _Soap._--This is a most important ingredient in printer’s ink, which
is not even mentioned in any of the recipes prior to that in the
Encyclopædia Britannica. For want of soap, ink accumulates upon the face
of the types, so as completely to clog them up after comparatively few
impressions have been taken; it will not wash off without alkaline lyes,
and it skins over very soon in the pot. Yellow rosin soap is the best
for black inks; for those of light and delicate shades, white curd soap
is preferable. Too much soap is apt to render the impression irregular,
and to prevent the ink from drying quickly. The proper proportion has
been hit, when the ink works clean, without clogging the surface of the
types.
4. _Lamp black._--The vegetable lamp black, sold in firkins, takes by
far the most varnish, and answers for making the best ink. See BLACK.
5. _Ivory black_ is too heavy to be used alone as a pigment for printing
ink; but it may be added with advantage by grinding a little of it upon
a muller with the lamp black, for certain purposes; for instance, if an
engraving on wood is required to be printed so as to produce the best
possible effect.
6. _Indigo_ alone, or with an equal weight of prussian blue, added in
small proportion, takes off the brown tone of certain lamp-black inks.
Mr. Savage recommends a little Indian red to be ground in with the
indigo and prussian blue, to give a rich tone to the black ink.
7. _Balsam of capivi_, as sold by Mr. Allen, Plough-court,
Lombard-street, mixed, by a stone and a muller, with a due proportion of
soap and pigment, forms an extemporaneous ink, which the printer may
employ very advantageously when he wishes to execute a job in a
peculiarly neat manner. Canada balsam does not answer quite so well.
After the smoke begins to rise from the boiling oil, a bit of burning
paper stuck in the cleft end of a long stick, should be applied to the
surface, to set it on fire, as soon as the vapour will burn; and the
flame should be allowed to continue (the pot being meanwhile removed
from over the fire, or the fire taken from under the pot,) till a sample
of the varnish, cooled upon a pallet-knife, draws out into strings of
about half an inch long between the fingers. To six quarts of linseed
oil thus treated, six pounds of rosin should be gradually added, as soon
as the froth of the ebullition has subsided. Whenever the rosin is
dissolved, one pound and three quarters of dry brown soap, of the best
quality, cut into slices, is to be introduced cautiously, for its water
of combination causes a violent intumescence. Both the rosin and soap
should be well stirred with the spatula. The pot is to be now set upon
the fire, in order to complete the combination of all the constituents.
Put next of well ground indigo and prussian blue, each 2-1/2 ounces,
into an earthen pan, sufficiently large to hold all the ink, along with
4 pounds of the best mineral lamp black, and 3-1/2 pounds of good
vegetable lamp black; then add the warm varnish by slow degrees,
carefully stirring, to produce a perfect incorporation of all the
ingredients. This mixture is next to be subjected to a mill, or slab and
muller, till it be levigated into a smooth uniform paste.
One pound of a superfine printing ink may be made by the following
recipe of Mr. Savage:--Balsam of capivi, 9 oz.; lamp black, 3 oz.;
indigo and prussian blue, together, p. æq. 1-1/4 oz.; Indian red, 3/4
oz.; turpentine (yellow) soap, dry, 3 oz. This mixture is to be ground
upon a slab, with a muller, to an impalpable smoothness. The pigments
used for coloured printing inks are, carmine, lakes, vermillion, red
lead, Indian red, Venetian red, chrome yellow, chrome red or orange,
burnt _terra di Sienna_, gall-stone, Roman ochre, yellow ochre,
verdigris, blues and yellows mixed for greens, indigo, prussian blue,
Antwerp blue, lustre, umber, sepia, browns mixed with Venetian red, &c.
PRINTING MACHINE. (_Typographie mécanique_, Fr.; _Druckmaschine_, Germ.)
In reviewing those great eras of national industry, when the productive
arts, after a long period of irksome vassalage, have suddenly achieved
some new conquest over the inertia of matter, the contemplative mind
cannot fail to be struck with the insignificant part which the
academical philosopher has generally played in such memorable events.
Engrossed with barren syllogisms, or equational theorems, often little
better than truisms in disguise, he nevertheless believes in the
perfection of his attainments, and disdains to soil his hands with those
handicraft operations at which all improvements in the arts must
necessarily begin. He does not deem manufacture worthy of his regard,
till it has worked out its own grandeur and independence with patient
labour and consummate skill. In this spirit the men of speculative
science neglected for 60 years the steam engine of Newcomen, till the
artisan Watt transformed it into an automatic prodigy; they have never
deigned to illustrate by dynamical investigations the factory
mechanisms of Arkwright, yet nothing in the whole compass of art
deserves it so well; and though perfectly aware that revolvency is the
leading law in the system of the universe, they have never thought of
showing the workman that this was also the true principle of every
automatic machine.
These remarks seem to be peculiarly applicable to book-printing, an art
invented for the honour of learning and the glory of the learned, though
they have done nothing for its advancement; yet by the overruling bounty
of Providence it has eventually served as the great teacher and guardian
of the whole family of man.
It has been justly observed by Mr. Cowper, in his ingenious lecture,[44]
that no improvement had been introduced in this important art, from its
invention till the year 1798, a period of nearly 350 years. In Dr.
Dibdin’s interesting account of printing, in the Bibliographical
Decameron, may be seen representations of the early printing-presses,
which exactly resemble the wooden presses in use at the present day. A
new era has, however, now arrived, when the demands for prompt
circulation of political intelligence require powers of printing
newspapers beyond the reach of the most expeditious hand presswork.
[44] On the recent improvements in printing, first delivered at the
Royal Institution, February 22, 1828.
For the first essential modification of the old press, the world is
indebted to the late Earl Stanhope.[45] His press is formed of iron,
without any wood; the table upon which the form of types is laid, as
well as the platen or surface which immediately gives the impression, is
of cast iron, made perfectly level; the platen being large enough to
print a whole sheet at one pull. The compression is applied by a
beautiful combination of levers, which give motion to the screw, cause
the platen to descend with progressively increasing force till it
reaches the type, when the power approaches the maximum; upon the
infinite lever principle, the power being applied to straighten an
obtuse-angled jointed lever. This press, however, like all its
flat-faced predecessors, does not act by a continuous, but a
reciprocating motion, and can hardly be made automatic; nor does it much
exceed the old presses in productiveness, since it can turn off only 250
impressions per hour.
[45] Lord Stanhope is the only man of learning whose name figures in
the annals of typography.
[Illustration: 913