hydrogen at a red heat, or by heating the metal with ethylene to 700°
C. (M. Guntz, _Comptes rendus_, 1896, 122, p. 244; 123, p. 1273), is a
white solid which inflames when heated in chlorine. With alcohol it
forms lithium ethylate, LiOC2H5, with liberation of hydrogen. _Lithium
oxide_, Li2O, is obtained by burning the metal in oxygen, or by
ignition of the nitrate. It is a white powder which readily dissolves
in water to form the _hydroxide_, LiOH, which is also obtained by
boiling the carbonate with milk of lime. It forms a white caustic
mass, resembling sodium hydroxide in appearance. It absorbs carbon
dioxide, but is not deliquescent. _Lithium chloride_ LiCl, prepared by
heating the metal in chlorine, or by dissolving the oxide or carbonate
in hydrochloric acid, is exceedingly deliquescent, melts below a red
heat, and is very soluble in alcohol. _Lithium carbonate_, Li2CO3,
obtained as a white amorphous precipitate by adding sodium carbonate
to a solution of lithium chloride, is sparingly soluble in water.
_Lithium phosphate_, Li3PO4, obtained by the addition of sodium
phosphate to a soluble lithium salt in the presence of sodium
hydroxide, is almost insoluble in water. _Lithium ammonium_, LiNH3, is
obtained by passing ammonia gas over lithium, the product being heated
to 70° C. in order to expel any excess of ammonia. It turns brown-red
on exposure to air, and is inflammable. It is decomposed by water
evolving hydrogen, and when heated _in vacuo_ at 50°-60° C. it gives
lithium and ammonia. With ammonia solution it gives hydrogen and
_lithiamide_, LiNH2 (H. Moissan, _ibid._, 1898, 127, p. 685). _Lithium
carbide_, Li2C2, obtained by heating lithium carbonate and carbon in
the electric furnace, forms a transparent crystalline mass of specific
gravity 1.65, and is readily decomposed by cold water giving acetylene
(H. Moissan, _ibid._, 1896, 122, p. 362).
Lithium is detected by the faint yellow line of wave-length 6104, and
the bright red line of wave-length 6708, shown in its flame spectrum.
It may be distinguished from sodium and potassium by the sparing
solubility of its carbonate and phosphate. The atomic weight of
lithium was determined by J. S. Stas from the analysis of the
chloride, and also by conversion of the chloride into the nitrate, the
value obtained being 7.03 (O = 16).
The preparations of lithium used in medicine are: _Lithii Carbonis_,
dose 2 to 5 grs.; _Lithii Citras_, dose 5 to 10 grs.; and _Lithii
Citras effervescens_, a mixture of citric acid, lithium citrate,
tartaric acid and sodium bicarbonate, dose 60 to 120 grs. Lithium
salts render the urine alkaline and are in virtue of their action
diuretic. They are much prescribed for acute or chronic gout, and as a
solvent to uric acid calculi or gravel, but their action as a solvent
of uric acid has been certainly overrated, as it has been shown that
the addition of medicinal doses of lithium to the blood serum does not
increase the solubility of uric acid in it. In concentrated or large
doses lithium salts cause vomiting and diarrhoea, due to a
gastro-enteritis set up by their action. In medicinal use they should
therefore be always freely diluted.
LITHOGRAPHY (Gr. [Greek: lithos], a stone, and [Greek: graphein], to
write), the process of drawing or laying down a design or transfer, on a
specially prepared stone or other suitable surface, in such a way that
impressions may be taken therefrom. The principle on which lithography
is based is the antagonism of grease and water. A chemically pure
surface having been secured on some substance that has an equal affinity
for both grease and water, in a method hereafter to be described, the
parts intended to print are covered with an unctuous composition and the
rest of the surface is moistened, so that when a greasy roller is
applied, the portion that is wet resists the grease and that in which an
affinity for grease has been set up readily accepts it; and from the
surface thus treated it will be seen that it is an easy thing to secure
an impression on paper or other material by applying suitable pressure.
The inventor of lithography was Alois Senefelder (1771-1834); and it is
remarkable what a grip he at once seemed to get of his invention, for
whereas the invention of printing seems almost a matter of evolution,
lithography seems to come upon the scene fully equipped for the battle
of life, so that it would be a bold craftsman at the present day who
would affirm that he knew more of the principles underlying his trade
than Senefelder (q.v.) did within thirty years of its invention. Of
course practice has led to dexterity, and the great volume of trade has
induced many mechanical improvements and facilities, but the principles
have not been taken any further, while some valuable methods have been
allowed to fall into desuetude and would well repay some experimentally
disposed person to revive.
Lithography may be divided into two main branches--that which is drawn
with a greasy crayon (rather illogically called "chalk") on a grained
stone, and that which is drawn in "ink" on a polished stone. Whatever
may be thought in regard to the original work of the artists of various
countries who have used lithography as a means of expression, there can
be little doubt that in the former method the English professed
lithographer has always held the pre-eminence, while French, German and
American artists have surpassed them in the latter.
Chalk lithography subdivides itself into work in which the black
predominates, although it may be supported by 5 or 6 shades of modified
colour--this branch is known as "black and tint" work--and that in which
the black is only used locally like any other colour. Frequently this
latter class of work will require a dozen or more colours, while some of
the finest examples have had some twenty to thirty stones employed in
them. Work of this description is known as chromo-lithography. Each
colour requires a separate stone, and work of the highest quality may
want two or three blues with yellows, reds, greys and browns in
proportion, if it is desired to secure a result that is an approximate
rendering of the original painting or drawing. The question may perhaps
be asked: "If the well-known three-colour process" (see PROCESS) "can
give the full result of the artist's palette, why should it take so many
more colours in lithography to secure the same result?" The answer is
that the stone practically gives but three gradations--the solid, the
half tint and the quarter tint, so that the combination of three very
carefully prepared stones will give a very limited number of
combinations, while a moderate estimate of the shades on a toned block
would be six; so that a very simple mathematical problem will show the
far greater number of combinations that the three blocks will give.
Beyond this, the chromo-lithographer has to exercise very great powers
of colour analysis; but the human mind is quite unable to settle offhand
the exact proportion of red, blue and yellow necessary to produce some
particular class say of grey, and this the camera with the aid of colour
filters does with almost perfect precision.
Notwithstanding these disadvantages, lithography has these strong
points: (1) its utility for small editions on account of its, at
present, smaller prime cost; (2) its suitability for subjects of large
size; (3) its superiority for subjects with outlines, for in such cases
the outline can be done in one colour, whereas to secure this effect by
the admixture of the three colours requires marvellously good
registration, the absence of which would produce a very large proportion
of "waste" or faulty copies; (4) capacity for printing on almost any
paper, whereas, at the time of writing, the tri-colour process is almost
entirely limited to printing on coated papers that are very heavy and
not very enduring.
With regard to the two branches of chalk lithography, the firms that
maintained the English supremacy for black and tint work in the early
days were Hulemandel, Day and Haghe and Maclure, while the best
chromo-lithographic work in the same period was done by Vincent Brooks,
the brothers Hanhart, Thomas Kell and F. Kell. In reference to the
personal work of professed lithographers during the same period, the
names of Louis Haghe, J. D. Harding, J. Needham, C. Baugniet, L. Ghemar,
William Simpson, R. J. Lane, J. H. Lynch, A. Maclure and Rimanozcy stand
for black and tint work; while in chromo-lithography J. M. Carrick, C.
Risdon, William Bunney, W. Long, Samuel Hodson, Edwin Buckman and J.
Lewis have been conspicuous among those who have maintained the standard
of their craft. In the foregoing list will be recognized the names of
several who have had admirable works on the walls of the Royal Academy
and other exhibitions; Mr Lane, who exhibited lithographs from 1824 to
1872, was for many years the doyen of lithographers, and the only one of
their number to attain academic rank, but Lynch and John Cardwell Bacon
were his pupils, and Bacon's son, the painter John H. F. Bacon, was
elected to the Royal Academy in 1903. In the first decade of the 20th
century the number of firms doing high-class work, and the artists who
aided them in doing it, were more numerous than ever, and scarcely less
able, but it would be outside the present purpose to differentiate
between them.
The _raison d'être_ of "stipple" work is its capacity for retransferring
without serious loss of quality, for it can scarcely be contended that
it is as artistic as the methods just described. Retransferring is the
process of pulling impressions from the original stones with a view to
making up a large sheet of one or more small subjects, or where it is
desired to print a very large number without deterioration of the
original or matrix stone. The higher class work in this direction has
been done in France, Germany and the United States, where for many years
superiority has been shown in regard to the excellence and rapidity of
retransferring. To this cause may be attributed the fact that the box
tops and Christmas cards on the English market were so largely done
abroad until quite recent times. The work of producing even a small face
in the finest hand stipple is a lengthy and tedious affair, and the
English craftsman has seldom shown the patience necessary for this work;
but since the American invention known as Ben Day's shading medium was
introduced into England the trade has largely taken it up, and thereby
much of the tedium has been avoided, so that it has been found possible
by its means to introduce a freedom into stipple work that had not
before been found possible, and a very much better class of work has
since been produced in this department.
About the year 1868 grained paper was invented by Maclure, Macdonald &
Co. This method consists in impressing on ordinary Scotch transfer or
other suitable paper a grain closely allied to that of the lithographic
stone. It appears to have been rather an improvement than a new
invention, for drawing paper and even canvas had been coated previously
with a material that adhered to a stone and left on the stone the greasy
drawing that had been placed thereon; but still from this to the
beautifully prepared paper that was placed on the market by the firm of
which the late Andrew Maclure was the head was a great advance, and
although the first use was by the ordinary craftsman it was not long
before artists of eminence saw that a new and convenient mode of
expression was opened up to them.
On the first introduction of lithography the artists of every nation
hastened to avail themselves of it, but soon the cumbrous character of
the stone, and the fact that their subjects had to be drawn backwards in
order that they might appear correctly on the paper, wore down their
newly-born zeal, and it was only when the grained paper system was
perfected, by which they could make their drawings in the comfort of
their studios without reversing, that any serious revival took place.
Although excellent work on grained paper had been done by Andrew
Maclure, Rimanozcy, John Cardwell Bacon, Rudofsky and other craftsmen,
the credit for its furtherance among artists must be given to Thomas Way
and his son T. R. Way, who did much valuable pioneer work in this
direction. The adhesion of such artists of eminence as Whistler, Legros,
Frank Short, Charles Shannon, Fantin Latour, William Strang, Will
Rothenstein, Herbert Railton and Joseph Pennell, did not a little to aid
lithography in resisting the encroachments of other methods into what
may still be considered its sphere. As a means of reproducing effects
which an artist would otherwise get by pencil or crayon, it remains
entirely unequalled, and it is of obvious advantage to art that
twenty-five or fifty copies of an original work should exist, which,
without the aid of lithography, might have only been represented by a
single sketch, perhaps stowed away among the possessions of one private
collector.
In regard to grained paper work, undue stress has often been placed upon
the rapid deterioration of the stone, some contending that only a few
dozen first-class proofs can be taken; this has led to the feeling that
it is unsuited to book illustration, and damage has been done to the
trade of lithography thereby. It may be mentioned that quite recently
about 100 auto-lithographs in black and three colours, the combined work
of Mr and Mrs Herbert Railton, have been treated by the Eberle system of
etching described below, and although an infinitesimal loss of quality
may have arisen, such as occurs when a copper etching is steel faced,
some 2000 to 3000 copies were printed without further deterioration, and
an edition of vignetted sketches was secured, far in advance of anything
that could have been attained from the usual screen or half-toned
blocks.
Grained paper is much used in the ordinary lithographic studio for work
such as the hill shading of maps that can be done without much working
up, but the velvety effects that in the hands of Louis Haghe and his
contemporaries were so conspicuous, cannot be secured by this method.
The effects referred to were obtained by much patient work of a
"tinter," who practically laid a ground on which the more experienced
and artistic craftsman did his work either by scraping or accentuation.
Where fine rich blacks are needed, artists will do well to read the
notes on the "aquatint" and "wash" methods described by Senefelder in
his well-known treatise, and afterwards practised with great skill by
Hulemandel.
Lithography is of great service in educational matters, as its use for
diagrams, wall pictures and maps is very general; nor does the influence
end with schooldays, for in the form of pictures at a moderate price it
brings art into homes and lives that need brightening, and even in the
form of posters on the much-abused hoardings does something for those
who have to spend much of their time in the streets of great cities.
According to the census of 1901, 14,686 people in the United Kingdom
found their occupation within the trade, while according to a Home
Office return (1906), 20,367 persons other than lithographic printers
were employed by the firms carrying on the business. As it may be
assumed that an equal number are employed in France, Germany, the United
States of America and the world at large, it is clear that a vast
industrial army is employed in a trade that, like letterpress printing,
has a very beneficial influence upon those engaged in it.
_Technical Details._--The following description of the various methods
of lithography is such as may be considered of interest to the general
reader, but the serious student who will require formulas and more
precise directions will do well to consult one of the numerous
text-books on the subject.
_Stone and Stone Substitutes._--The quality of stone first used by
Alois Senefelder, and discovered by him at the village of Solenhofen
in Bavaria, still remains unsurpassed. This deposit, which covers a
very large area and underlies the villages of Solenhofen, Moernsheim
and Langenaltheim, has often been described, sometimes for interested
motives, as nearly exhausted; but a visit in 1906 revealed that the
output--considerable as it had been during a period little short of a
century--was very unimportant when compared to the great mass of
carbonaceous limestone existing in the neighbourhood. The strong point
in favour of this source of supply, in addition to its unrivalled
quality, is the evenness of its stratification, and the fact that
after the removal of the surface deposits, which are very thin, the
stones come out of large size, in thickness of 3 to 5 in., and thus
just suited for lithographic purposes and needing only to be wrought
in the vertical direction. Other deposits of suitable stone have been
found in France, Spain, Italy and Greece, but transit and the absence
of suitable stratification have restricted them to little more than
local use. Beyond this, few of the deposits other than in the
neighbourhood of Solenhofen have been of the exact degree of density
necessary, and the heavier varieties do not receive the grease with
sufficient readiness. The desire to find other sources of supply has
been stimulated by the social conditions existing in southern Bavaria,
for the quarries are largely owned by peasant proprietors, who have
very well-defined business habits of their own which make transactions
difficult. Among other things, they will seldom supply the highest
grades and the largest sizes to those who will not take their
proportion of lower quality and smaller sizes; and this, in view of
the very expensive transit down the Rhine to Rotterdam, with a railway
journey at one end and a sea journey at the other, is a source of
difficulty to the importer in other countries.
The earliest substitute for lithographic stone was zinc, which has
been used from early days and is now more in demand than ever; it
requires very careful printing as the grease only penetrates the
material to a very slight extent, and the same must be said in regard
to the water. From this cause, when not in experienced hands, trouble
is likely to arise; and when this has occurred, remedial methods are
much more difficult than with stones. When put away for storage, a dry
place is very essential, as corrosion is easily set up. At first the
plates were quite thick, and almost invariably grained by a zinc
"muller" and acid; now a bath of acid is more generally used, and the
operation is known as "passing," while the plates are quite thin,
which renders them suitable for bending round the cylinders of rotary
machines.
So far we have been dealing with plain zinc, but variations are
caused, either by the oxidization of the surface or by coating the
plate with a composition closely allied to lithographic stone and
applied in a form of semi-solution. This class of plate was first
invented by Messrs C. & E. Layton, and a modification was invented by
Messrs Wezel and Naumann of Leipzig, who brought its use to a high
pitch of perfection for transferred work such as Christmas cards. A
treatment of iron plates by exposing them to a high temperature has
recently been patented, and has had some measure of success, while the
Parker printing plate, which is practically a sheet of zinc so treated
as to secure greater porosity and freedom from oxidization, is rapidly
securing a good position as a stone substitute.
_Preparation of the Stones._--In this department the cleanliness so
necessary right through the lithographic process must be carefully
observed, and a leading point is to secure a level surface and to
ensure that the front and back of the stone are strictly parallel,
i.e. that the stones stand the test of both the straight edge and the
callipers. A good plan to ensure evenness on the surface is to mark
the front with two diagonal lines of some non-greasy substance till
the top stone (which should not be too small, and should be constantly
revolved on the larger one) has entirely removed them. The application
of the straight edge from time to time will end in securing the
desired flatness, on which so much of the future printing quality
depends. The usual method is to rub out with sand, and then rub with
pumice and polish with water of Ayr or snake stone. For chalk work,
the further work of graining has to be done by revolving a small stone
muller on the surface with exceedingly fine sand or powdered glass.
Many appliances (some very expensive) have been devised for doing the
principal part of this work by machine--none more effective than those
methods by which a disk of about 12 in. is kept revolving on a rod
attached to the ceiling, guided by hand over all parts of the stone;
but for large surfaces the ceiling needs to be rather high so as to
allow of a long expanding rod reaching the surface at a moderate
angle. When this machine is fitted with friction disk driving, very
wide variations of speed are possible, and the machine can be driven
so slowly and evenly as to secure a very fair (but not first class)
grain, in addition to speedy rubbing out, which is the chief aim of
the apparatus.
_Preparing a Subject in Chalk or Chalk and Tints._--This branch of
work is much less in demand than formerly. A grey stone having been
selected and finely grained with sand or powdered glass passed through
a sieve of 80 to 120 meshes to the lineal inch, and the artist having
made his tracing, this tracing is reversed upon the stone with the
interposition of a piece of paper coated with red chalk, and the chalk
side towards the surface; the lines on the tracing are then gone over
with a tracing point, so that a reproduction in red chalk is left upon
the stone. It will then be desirable to secure a stock of pointed
Lemercier chalks of at least two grades, hard and soft: the pointing
is a matter that requires experience, and is done by the worker
drawing a sharp pen-knife towards him in a slicing manner as though
trying to put a point upon a piece of cheese. Care should be taken
that the falling pieces are gathered into a box, or they may do
irreparable mischief to the work. The work of outlining is done with
No. 1 or hard chalk, and until experience is gained it will be well to
depend chiefly on this grade, securing rich dark effects by tinting or
going over the stone in various directions and then finishing with
lithographic ink where absolute blacks are required. This ink
(Vanhymbeck's or Lemercier's are two good makes) needs careful
preparation, the method being to warm a saucer and rub the ink dry
upon it, then add a little distilled water and incorporate with the
finger. It is of great importance not to use any ink left over for the
next day, but always to have a fresh daily supply.