FOR TRANSPARENCIES AND LANTERN SLIDES,
Ire without doubt the simplest in manipulation,
the best in technical results, and therefore
t ! he most papular Lantern Plates in the World.
[r, E, H. JACQtJES, of Birmingham, carried off the First Prize
against 250 Competitors last year in Transparencies
on our Lantern Plates !
[r. PAUL LAME (Liverpool) writes us:
'This year, as last, 1 find your LANTERN PLATES give
:cellent results. I have just taken, the First Prize for Slides
the Birkenhead Photo Society. My Work was on your Plates."
?he "AMATEUR PHOTOGRAPHER" says:
i ' ' We cannot refrain from saying a word in praise of FRY'S
fANTERN PLATES. We have just seen a batch of most beautiful
Lides, made on these Plates by Mr. A. R. DEESSEE."
PRICE is. per dozen,
complete with Developer, Round Masks, Gummed Black
Paper Edging, and Clear Glasses, 2s. per dozen.
^ Fry's 2nd Grand Lantern Plate Competition, 1888-9.
PARTICULARS READY SHORTLY.
[amActonrg of flu " KINGSTON SPECIAL " Dry Plates, &
5, Chandos St., Charing Cross,
fakr: XiigttoMB-Ifcuiu. TelsgrajUc Adtes: "SnlMjements, London."
TOILERS OF THE THAMES-
A Lantern Slide, by the Author.
Ppaetieal dr&icU: to t|?e: Wopking oj^
Optical (OP Magiej
With full and precise directions for making and colouring Lantern
T. C. HEPWORTH, F.C.S.,
(For many years Lecturer to the Royal Polytechnic Institution,
London; Lecturer on Photography at the Birkbeck Institution;
and Editor of "THE CAMERA.")
WYMAN & SONS, GREAT QUEEN STREET, LINCOLN' S-!NN FIELDS, W.C.
WYMAN AND SONS, PRINTERS, GREAT QUEEN STREET,
I. The Construction of the Lantern .... 1
II. The Optical System of the Lantern ... 16
III. Oxygen Gas Making 30
IV. Limelight Jets, Kegulators, Pressure Boards, &c. . 50
V. The Limelight and its Management . . .71
VI Screens ........ 6
VII. The Preparation of Lantern Slides, Diagrams, &c.,
without the aid of Photography . . . .97
VIII. Lantern Slide Making by the Wet (Photographic)
Process ^ . . 104
IX. Lantern Slides on Dry Plates . . . .109
X. Home-made Gelatine Plates 125
XI. On Colouring Photographic Transparencies for
Lantern Slides 145
XII. The same subject continued 159
XIII. Description of various Experiments Chemical,
Electrical, &c. for Class Instruction, which are
possible with the Lantern 171
XIV. The Lantern as an Aid to the Photographer . . 204
XV. The Art of Making Photo-Micrographs . .211
XVI. Enlarging Photographs with the Lantern . 222
XVII. The Lantern Microscope and the Opaque Lantern . 240
XVIII. Various Lantern Accessories . . . 250
XIX. Practical Hints to those who Employ the Lantern
for Scientific Demonstration or for Entertain-
ments in the Drawing- Koom or Lecture Hall . 2(54
]S it is customary for an author to say a few
words to his readers by way of introduction,
before they become better acquainted with
one another, let me briefly state the reason why
this book is written, and why I felt some confidence
in undertaking the work. The magic lantern has
always been one of the most popular instruments
ever made. So popular has it been, that children by
the thousand recognise its charms, while many of more
mature years have a secret hankering after it, which
they would fain leave unacknowledged : " For it is but a
toy," think they, " and we have left toyland behind
us since we reached man's estate." Let me
sympathise with these feelings, and own for my part
a weakness for pantomimes and fireworks, which
weakness I have occasionally the opportunity of
indulging, on the plea of taking my children out for
a treat. But let me say at once that the magic lantern
is now no toy, but is recognised as a valuable aid to
education far and wide. The reason for this is not
far to seek. First, we have to look at the vast
improvement in the instrument itself. So long as the
greasy, evil-smelling oil lamp was almost the sole
illuminant available, and roughly executed daubs in
varnish colours on glass the only works of art (?)
which could be purchased for the lantern, it did not much
signify that the lenses were also of a faulty character,
and no better in quality than the " bull's eye " of the
nocturnal policeman. But when the brilliant limelight
came to be adapted to the lantern, it was at once seen
that the capabilities of the instrument were not only
much increased, but almost without limit. It would
be difficult to say offhand how many persons visited
the Royal Polytechnic Institution in the forty years
during which it was open to the public; but it is
within my own experience that at one period, at the
time of the ( ' ghost " illusion, they came at
the rate of two thousand per diem. There is no
doubt whatever that the Polytechnic caused this form
of amusement to become popular, for the lecturers
affiliated to the Institution travelled the country
round, and gave similar entertainments in all parts.
There are few branches of science in which the
optical lantern cannot be made useful for purposes of
demonstration, and as this fact becomes better known,
every schoolroom in the kingdom will be provided
with one. In every lecture theatre worthy of the
name the instrument is already constantly called upon
to illustrate various subjects, and I venture to state
that its use will be greatly increased now that so
much attention is being paid to the art of photo-
micrography, by which enlarged pictures of micro-
scopic objects can be easily rendered available for
projection by means of the lantern. A large class
of students can thus at the same moment study the
structure of an organism which may be in reality
invisible to unaided sight by reason of its minute
But during the past few years, the number of those
who interest themselves in the lantern and its
capabilities has been vastly increased by the sudden
popularity of the art of photography. Amateur
photographers are now to be found in every town in
the kingdom, and they are beginning to find out that
there is no better method of showing their friends the
pictures which they have taken than by means of the
optical lantern. The same instrument, too, as it
offers a means of making permanent enlarged copies
of small photographs, serves with them a double
The introduction as illuminants of the hydrocar-
bons, under the name of petroleum, paraffin, kerosene,
&c., has also had its share in the recent development
of the optical lantern, for now a few pounds will
purchase a better instrument than was procurable at
any price twenty years ago.
With these facts in view, I have long thought that
a thorough guide to the working of the optical lantern,
the preparation of its diagrams and pictures, the
colouring of the same, the production of photo-
micrographs, and everything pertaining to lantern
work, would fill a vacant place in technical literature.
Beyond the two or three shilling handbooks which
have appeared, there is nothing of the kind procurable;
and in the space available in such books, it is obvious
that the various matters to which I have referred
cannot be sufficiently dealt with.
Some of the matter here printed has already
appeared in The Amateur Photographer, and in The
Camera. The author is indebted to the proprietors of
both those periodicals for their courtesy in allowing
both text and cuts to be reproduced in this work.
T. C. HEPWORTH.
45, ST. AUGUSTINE'S EOAD, CAMDEN SQUARE,
THE CONSTRUCTION OF THE LANTERN.
that wonderful autobiography of Benvenuto
Cellini, which Horace Walpole described as
being " more amusing than any novel," we
find the account of a weird incantation scene which
took place in the Colosseum at Rome. Cellini tells us
that he had made the acquaintance of a Sicilian priest
who volunteered to initiate him into some of the
secrets of necromancy. A meeting was appointed at the
Colosseum, where " the priest, having arrayed himself in
necromancer's robes, began to describe circles on the earth
with the finest ceremonies that can be imagined. I must
say that he made us bring precious perfumes and fire, and
also drugs of fetid odour. When the preliminaries were
completed, he made the entrance into the circle j and
taking us by the hand, introduced us one by one inside it.
Then he assigned our several functions : to the necromancer,
his comrade, he gave the pentacle to hold ; the other two
of us had to look after the fire and the perfumes ; and
then he began his incantations. This lasted more than an
THE BOOK OF THE LANTERN.
hour and a half, when several legions appeared, and the
Colosseum wa's^a'lk^all of devils." It has been suggested
that these effects* w'er'e' produced by some form of lantern
.das&ji^ ;imtag'6s[ oil .'the fcmoke from the burning drugs.
Should this surmise be correct, it would refer the use of
the instrument back to the early half of the sixteenth
century Cellini having been born at Florence in the
year 1500 and the event spoken of having occurred in
his early manhood.
But on careful perusal of the entire account of these
supernatural wonders, I feel convinced that no kind of
optical instrument can have been used. To produce any
remarkable effect in such a large space as that covered by
Vespasian's Amphitheatre would certainly tax the powers
of the best modern lantern. Besides which, Cellini was
a remarkably clever and observant man, and would
probably have detected the employment of any such
apparatus. It is far more probable that the priest was
aided by a number of confederates, and that these were in
THE BOOK OF THE LANTERN. . So
reality the legions of devils which so impressed the super-
stitious mind of the Florentine goldsmith and sculptor.
With far more reason might we suspect the use of the
lantern in those manifestations which are said to take
place among the so-called spiritualists and their mediums-
We are certainly on much firmer ground when we
ascribe the first conception of the instrument to Athanasius
Kircher, the learned Jesuit of the seventeenth century,
who has left so many volumes to testify to the great gifts
which he possessed. For in one of these books, Ars Magna
Lucis et Umbrce, we not only find descriptions and dia-
grams of numerous optical contrivances (I may note in
passing that many of these drawings, redressed and
elaborated, appear in modern text-books as new ideas),
but several which show that Kircher quite understood the
main principle upon which the optical lantern depends.
A tracing of one of these rude cuts is given at fig. 1,
from which it will be seen that the design to be projected
by the lens is illuminated by three candles the brightest
form of artificial light then known and an inverted
image is thrown upon a screen at a distance.
Here we have practically the germ of the aphengescope,
or opaque form of lantern. But modern writers on the
subject, in referring to Kircher, have curiously overlooked
this most suggestive drawing, and have given another one
from his book, which they erroneously describe as the first 1
form of magic lantern. This I also reproduce (see fig. 2).
The description appended to the cut certainly does not
bear out that view, but points rather to a means of . in -
4 THE BOOK OF THE LANTERX.
creasing the light from any lantern by using a parabolic
reflector behind the lamp or candle flame. The passage
(translated) runs as follows :
" To construct an ingenious lantern which may show
things written at a great distance so that they can be
" Let a lantern be made of the same cylindrical figure
as you see here represented, in whose base let a concave
mirror be placed, having as parabolic a shape as is possible.
Within the focus of this mirror let F, the flame of a
candle, be fixed, and you will have "what is required, for
it will shine with such unwonted splendour as to show by
night, without any trouble, even the smallest letters when
examined by the aid of a telescope. But persons looking
at the flame from a distance will think that it is a great
fire. If the inner sides of the cylinder are fashioned of
polished tin in the form of an ellipse, they will increase
the light. But the figure here given will sufficiently show
THE BOOK OF THE LANTERN. O
the invention. E marks the handle and the opening (or
window) ; C the chimney or fnnnel."
It is worthy of note that Sir David Brewster, in his
" Natural Magic," qnotes the incantation scene from
Cellini at length, and states his conviction that the
appearances were brought about by optical apparatus,
although he admits that little was known of the action of
mirrors and lenses nntil the time of Kircher.
It is obvious, however, that such primitive instruments
were of the crudest kind, and can only be regarded as
interesting curiosities. Up to within quite recent times
lanterns for projection held about the same relation to the
modern instrument as does the bone needle of the cave
men to the sewing machine. Like most instruments of
precision, the optical lantern is the outcome of many years
of patient thought and labour, and is the result of the
working of many minds. No individual can be credited
with its invention or discovery. The crude idea is, as we
have seen, to be found in Kircher's book, and one improve-
ment has been suggested here, and another there, until we
have before us a very perfect optical appliance.
The gradual advance in the instrument very naturally
follows the introduction of improved illuminants for more
general purposes. The oil lamp was superseded by the
argand gas-burner, and this was in its turn supplanted by
the whiter and better light afforded by mineral oil, while
before this, for the better kind of lanterns, Lieutenant
Drummond's brilliant limelight was quickly adopted as the
best for the purpose. This, too, may possibly, in the near
future, give way to the still more brilliant electric arc
O THE BOOK OP THE LANTERN.
light. But the introduction of mineral oil, in conjunction
with the adaptation of photography to lantern pictures,
have been the main factors in giving the instrument its
The first lantern burning mineral oil, and called the
Sciopticon, came to us from America. It was constructed
on scientific principles, and was far in advance of anything
of the kind before produced. It possessed good lenses
and a powerful lamp, the two broad wicks of which were
placed edgeways towards the condenser. The lamp was so
closed in that it formed a combustion chamber, and burnt
the oil under the best conditions. The lantern, however,
" FIG. 3.
had its faults. The front glass of the lamp was apt to
break, and a dark vertical line was always seen upon the
sheet a line which was in reality the image of the dark
space between the two wicks. By adding a central wick,
and by making certain alterations in the ventilation of the
lamp chamber, Messrs. Newton conquered both these
difficulties, and a far more perfect form of lantern has
THE BOOK OF THE LANTERN. 7
been the result. The same makers have, too, made the
lamp distinct and separate from the lantern, so that, if
required, it can readily be removed, and a lime-jet used
in its stead. The form of lamp referred to is shown in
fig. 3, both open for trimming and closed as in use,
while a complete mineral oil lantern, of the kind
now adopted by most makers, is seen at fig. 4. The
management of oil lanterns is so simple, really resolving
itself into the necessity for keeping the burning wicks at
a correct height, and putting the slides or pictures on the
stage provided for them, that no more space need be
devoted to this portion of my subject.
The great advantage of using a pair of lanterns is that
whilst a picture is being shown by one, another picture is
being made ready in the other, and there is no pause or
blank screen when the change is made. The so-called dis-
solving views, which are produced by making this change
slowly, made a great sensation when they were first intro-
8 THE BOOK OF THE LANTERN.
duced, perhaps because few knew exactly how they were
managed. But they are now so common that many
persons consider them rather tiresome than otherwise.
Still, they give the operator a ready means of varying his
work, if the dissolving apparatus be used with judgment.
Thus most beautiful effects can be obtained in landscapes,
more especially in seascapes, by using photographic
cloud pictures, the gradual blending of one clouded sky
into another giving fine aerial and very natural results.
In one set of pictures which I prepared to demonstrate
the beauties of cloudland, in connexion with a lecture on
ballooning, a sunrise picture was made to melt into a sun-
set picture, and in due time this latter gave place to a
moonlight effect. I am convinced that much can be done
in this direction if time can be given to the preparation of
THE BOOK OF THE LANTERN. 9
Originally for such effects two separate lanterns were
used side by side, but now a biunial lantern, with one
optical system above the other, is employed (see fig. 5).
The modern arrangement is far more convenient for the
operator, for the apparatus is compact and every adjustment
is within easy reach of his hand. A lantern so constructed
generally consists of a strong wooden body, lined with metal,
with cells for the reception of the condensing lenses.
Openings at the back shaped thus JL allow for the necessary
to and fro motion of the lime jets and their trays.
Between these openings, on the outside of the lantern
body, is fixed the dissolving key or tap, connected by india-
rubber tubes with the two jets (see fig. 6). In front of the
instrument are the stages for the reception of the slides, and
the metal plates to which are affixed the telescopic tubes for
holding the objective lenses. These plates are hinged, and
their inclination upward or downward to make the two
discs concentric on the sheet or screen is governed by
milled headed screws. The objectives can by this means
be made to slightly approach one another, while the con-
densers remain fixed. It is obvious that it would be better
10 THE BOOK OF THE LANTERN.
if the condensing lens also moved with the objective so
that the optical axis of one should agree with the
other. This could easily be done by making the upper
lantern move on a central pivot, and clamping it with a
fixed screw ; but the more faulty and elaborate plan has
been adopted by manufacturers, and will probably hold its
own for a long time yet.
It is certainly too much the fashion to adorn lanterns
with a mass of heavy brass-work. Like any other adorn-
ment, the brightly-lacquered brass looks well enough, but
represents, to my thinking, a waste both of material and
of workmanship, which adds greatly to the cost of an
instrument, without adding one jot to its efficiency. In-
deed, this brass-work is a positive disadvantage when a
lantern has to be carried from place to place by a busy
lecturer, and constitutes, not only an inconvenience, but a
tax, in the shape of "excess luggage." This superfluous
metal must, I suppose, be looked upon as a custom of the
trade, which it is very difficult to break down. It is the
same case with the microscope, the delicate brass-work of
which often costs more than the lenses, expensive though
the latter are. In each case the metal-work represents a
convenience in operating the instrument, but much of it
could be dispensed with, without in any way detracting
from its performance. We may, I think, gain a lesson
in the construction of an ideal lantern by examining
a modern photographic camera for tourists' use, where the
greatest rigidity is combined with extreme lightness, and
metal is used but sparingly. Looking at such an
instrument, we find that it must be extended for focus-
THE BOOK OF THE LANTERN. 11
sing purposes, and that its chief expanding part is made
of folded leather (concertina bellows fashion). Now, why
should not the same arrangement be adopted for the
optical lantern ? We here require a similar extension of
the front of the instrument, in order to suit the foci of
the different lenses employed, and according to the dis-
tance and size of the picture which we wish to project on
the screen before us. Surely some arrangement of the 1
kind could be adapted to the lantern. If such a change
of construction were brought about, and with analogous
alterations in other parts, the weight of a double or triple
lantern would certainly be reduced to about one-third of
of what it is at present. It may, perhaps, take some time
for opticians to appreciate this view of the case, and there
may be good trade reasons for not making a change of
such a radical nature. I am not behind the scenes, and
so cannot tell. It might certainly be urged with some
truth that there is no need to be in a hurry to alter the
present type of lantern, seeing that lightness of construc-
tion may soon be brought about by the substitution of
aluminium for brass. The production of the former
metal is daily becoming cheaper, and as its weight, bulk
for bulk, is about one-third that of brass, and as it is
strong, not easily tarnished, and in other respects is suit-
able for the purpose of lantern construction, we may look
forward to its adoption in this service.
Where a lantern is used for educational purposes it
requires certain additions which are quite unnecessary in
exhibition instruments. On the other hand, several
ornamental adjuncts which are desirable in the latter
12 THE BOOK OF THE LANTERN.
form of lantern may be dispensed with in the instrument
designed for the lecture or school room. Indeed, in an-
other chapter I point out how a very simple arrangement
of lamp and lenses can be made serviceable for educational
work. One of the most important additions to an instru-
ment used for teaching is what is known as the
vertical attachment. The object of this arrangement
THE BOOK OF THE LANTERN. 13
is to show certain preparations and other objects which
must be kept in a horizontal position during exhibition.
" Horizontal Attachment " would, therefore, perhaps be a
more sensible name for the apparatus the construction of
which can be easily understood by reference to the annexed
cut (fig. 7). The round opening in front, four inches in
diameter, is the place where the apparatus fits on to the
lantern, the lenses, &c., of the latter having been removed
for its accommodation. So that the light from the lantern is
received by the sloping mirror, and is reflected upwards
through a condensing lens, which is placed horizontally.
This lens forms a table or stage upon which different slides
or preparations can be laid for exhibition. The image is
formed by the lens above, and by the prism above that is
redirected and cast upon the sheet or screen. It is obvious
that some loss of light must result from filtering the rays
through so many media, but this cannot be helped. In
the chapter dealing with experiments possible with the
lantern the use of this vertical attachment will be further
alluded to, when its value will be better appreciated.
Double lanterns to burn oil are usually placed side by
side, but fig. 8 shows a convenient form of lantern which
has been recently introduced, and which is so constructed
that one lantern can be detached from its fellow. Thus,
when the lime-light is used they are adjusted one above
the other, and when the oil lamp is employed they are
placed side by side. Mr. Tyler has still more simplified
the matter by inventing a biunial lantern which burns
oil, although the position of the two lamps is one above the
other. This he achieves by the use of a bent chimney,
THE BOOK OF THE LANTERN.
which proceeds from the lower lantern and carries away
the hot air, so that it cannot influence the lamp above.
In the triple lantern (fig. 9) we have three optical
systems, and of course three lime-lights. This is the
exhibition instrument par excellence , and is commonly
used by those exhibitors who may be described rather as
entertainers than lecturers. . The third lantern is in reality
not often used. It is kept in reserve for producing occa-
sional effects while the other two lanterns are at work.
In some respects the optical lantern resembles the king of
musical instruments, for the effects which can be produced
by it are dependent upon and limited by the number of its
parts. If an organ has but one row of keys, the instrument
can do little beyond furnishing an accompaniment. With
THE BOOK OF THE LANTERN.
two rows its capabilities are much increased, for the organist
can use them alternately in contrast with one another, or
can combine them. With three claviers, his powers are
once more amplified, and he can introduce those changes
of musical colour for which our language provides no
descriptive word. So it is with the lantern. If it have
but one optical system the operator can only use it as a
means of showing simple pictures or diagrams. If it have
two systems he can produce the popular dissolving views ;
and if it be provided with a third set of lenses, he can
mingle with the views shown those " effects," as they are
called, which are so welcome to an audience of young
folk, and very often to children of a larger growth.
THE OPTICAL SYSTEM OF THE LANTERN.
jHE three great essentials of a good optical lantern
are the light, the condenser, and the objective, the
two latter forming the optical system of the instru-
ment. Theoretically, the light to give the best results should
be a mere point of radiance, but unfortunately this is
at present almost unattainable. I say almost, because I
believe it to be quite within the bounds of possibility to con-
struct an electric arc light which shall fulfil all the conditions
as to steadiness, uniformity of action, and maintenance of
a fixed position, which are required in lantern work. Such
a light has not yet been found, but when electricity
becomes more general as a source of illumination in our
cities and towns, as it .surely will, an arc light or
regulator of the required description will, I feel confident,
soon be forthcoming. The invention of such a con-
trivance, when the means of obtaining the requisite
current to feed it is so limited, would at present have the
disadvantage of coming before its time. The electric
arc light has been used more than once experimentally
in the lantern, with the most promising results.
THE BOOK OF THE LANTEEN.
The best source of illumination for the lantern
is, when we exclude electricity for the reasons just
indicated, the lime-light. It has the good qualities
of intense whiteness, steadiness, ease of management,
portability, and although not a point, its area of radiance
is not much greater than the space covered by a pea. I
shall describe in detail the method of its production and
management later on.
Having then a convenient form of intense light, we have
next to consider the means of using it to the best ad-
vantage. We must start with the acknowledgment that
in enlarging the image of a picture we must sacrifice a
large amount of light. But by using properly-constructed
lenses, we can make this loss as little as possible. As
already pointed out, the optical system of a lantern
consists of two distinct parts, the condenser and the
As many of my readers may be quite unacquainted with
the matter under consideration, I will point out why this
double system is necessary, and describe the work per-
formed by each set of lenses. In the annexed diagram,
fig. 10, L represents the lime cylinder, with rays of light
emanating from it and illuminating the picture P, which
THE BOOK OF THE LANTERN.
we require to show in an enlarged form. is the objective
lens by which this enlargement is to be brought about ;
the sheet or screen upon which the picture is projected
being supposed to be far away to the right. With such an
arrangement of parts what should we see on that screen ?
In the first place we should have but a very feeble light,
for as will be seen by reference to the diagram, most of
the luminous rays are wasted altogether, only the cen-
tral ones proceeding through the lens 0. It will be
seen also that these rays go through the central portion
of the picture only, and that therefore only this part
can be projected on to the distant screen. So that as a
result of our first efforts at lantern projection, we get an
indistinct and badly-lighted portion of a picture presented
to us. How can we remedy this state of things ? Ob-
viously, the thing to be done is to cause more of the rays
from our light source to be utilised, and this can be brought
about by placing between that light and the picture a lens
which shall condense the light upon that picture, and which
is therefore known as the condenser.
In fig. 11 we see a repetition of the diagram, fig. 10, with
the addition of a condenser, shown in this case, for the
sake of simplicity, as a single lens. Referring once more
THE BOOK OF THE LANTERN. 19
to this imaginary picture upon our screen, we now see that
it is complete. It is no longer the central fragment of a
design, but covers the sheet, and is equally illuminated.
We can at once see the reason for this welcome change by
looking once more at our revised diagram, fig. 11. The
rays of light instead of being wasted in illuminating the
inside of the lantern box, are refracted by the lens which
we have introduced, and are bent towards the objective.
In my diagrams, for the sake of simplicity, I have
represented each lens as consisting of a single piece of
glass of plano-convex form. Such lenses are found in toy
lanterns of the cheapest kind, but are, as might be ex-
pected, extremely faulty in performance. In the enlarged
picture, they give, owing to their total want of correction,
badly-defined margins, curved lines, and fringes of colour.
Having now seen the purpose fulfilled by the condensing
lens of the optical lantern, let us further consider its best
form, and let me at once correct an error into which a
purchaser is likely to fall. I have sometimes heard the
possessor of a lantern speak somewhat boastingly of his
instrument as one with 5, or perhaps 6 -inch condensers,
the more ordinary size being 4 inches, and often only
3 1 inches. For lantern projection, any size over 4 inches
is a positive disadvantage, and instead of representing a
gain, means really a great loss of light. The reason for
this is readily seen. What may be called the standard size
for a lantern picture is 3 inches in diameter (the entire
slide with its margin measuring 3J inches). If the picture
be framed in a circular 3-inch mount, a 3J-inch condenser
will amply illuminate it. If, however, the orifice of the
20 THE BOOK OF THE LANTERN.
mount be square or cushion-shaped, such a small condenser
would infallibly cut off the corners of the projected image,
and for such pictures, therefore, a 4-inch condenser is
necessary. But the smaller condenser transmits more
light, for the reason that being of shorter focus, the lime
cylinder is brought nearer to it. Some well-known
exhibitors, seeing the great importance of getting all the
light upon the screen that they possibly can, use nothing
but 3J-inch condensers, but this obliges them to confine
themselves to round pictures. On the whole, I prefer
myself the 4-inch condenser, for although I lose some
light, I can make use of any shaped pictures or diagrams
which may be required. (If the lantern be used for
photographic enlarging purposes, then a large-sized con-
denser is the great thing needful, at least, we must have
one of a size large enough to cover the negative which
has to be enlarged ; a quarter-plate size necessitating a v
5 -inch condenser and so on. But in that case brilliancy
of image is quite a secondary matter, and is compensated
for by extension of time occupied in the operation.) It
must also be borne in mind that, quite apart from the
question of focal length of the condensing lens, there is a
limit to the near approach of the incandescent lime
cylinder towards it, for the intense light is naturally ac-
companied by a fervent heat, which will surely crack
a lens if it be too near to ifc. In the chapter on the
working of the lime-light, precautions against this accident
are fully dealt with.
There are two forms of condensers, either of which
may be commonly found in commercial lanterns. One
THE BOOK OF THE LANTERN.
consists of a pair of plano-convex glasses mounted in one
cell, with their curved surfaces all but touching one another.
This form was, I believe, first introduced with the
American sciopticon. It is shown at fig. 12. The other
form of condenser is that devised (but not for lantern use)
by Sir John Herschell, and which consists of a double
convex lens, associated with a meniscus, the concave side
of the latter being next the radiant point, as shown in
fig. 13. In a good condenser we want not only quantity
of light, but also good quality, and these properties can
only be secured by careful attention to certain points of
construction. Quantity of light is governed by size and
focal length, as already pointed out, and it may be as well
to indicate here the manner in which lanterns furnished
with condensers of larger size than I have recommended
may be made to transmit a greater amount of light by the
interposition of another lens. There were at the old Poly-
technic Institution some antique lanterns with 10-in. con-
densers, this large size being necessary to cover the 8 -in.
hand-painted transparencies which were in use before
photography worked a revolution in such things. Such a
large condenser, of course, meant a great loss of light, as
THE BOOK OF THE LANTERN.
already pointed out. So the suggestion was made that a
small lens should be interposed between the light and the
condenser. This was done with a wonderful gain in the
performance of the old lanterns. Fig. 14 will show how
the additional lens brought this improvement about. Many
other forms of condensing lenses have from time to time
been suggested and experimented with, some of these em-
ploying three or more combinations. But these various
patterns, although one or two of them seem very promising
in form, have not been taken in hand by makers generally,
possibly on the score of expense, and probably owing as
much to that hesitation and laziness common to human
nature, which keeps us all to a well-beaten track.
But a few years ago the question of lantern lenses was
revived by a paper read by the late Mr. J. H. Dallmeyer
before the Photographic Society of Great Britain. The
reader of this excellent contribution to the subject, explained
in the first instance that a well-known worker with the
lantern h^cl called his attention to the great want of more
THE BOOK OF THE LANTERN. 2i>
perfect lenses for use with the instrument. Mr. Dallmeyer
thereupon determined to tackle the subject, and produced
new forms of condensers and objectives, a description of
which he placed before the Photographic Society. I can-
not do better than quote the description of the new eon-
denser from this paper, and at the same time reproduce
one of the drawings shown in illustration of the remarks
made (see fig. 15) :
" The condenser is of 4-in. effective diameter, and 2J-
in. equivalent focal length. Assuming the light to be at
a safe distance of 2| in. from the flat surface of the first
lens, this condenser collects an angular pencil of about
66, i.e., about 20 per cent, more light than the shortest
focus symmetrical. It consists of two unsymmetrical
lenses, A and B. A is a plano-convex of flint 3|-in.
diameter, and B is a double convex of crown glass of 4-in.
diameter. The lenses are mounted at a certain distance
apart, with their deep sides facing each other. Approxi-
mate correction of chromatic aberration for centrical pencils
is obtained by a proper apportioning of their focal lengths,
and the distance at which they are placed. Thus : ray
24 THE BOOK OF THE LANTERN.
L R, after refraction by lens A, diverges into a prismatic
beam; this falls upon different parts of lens B, which,
while acting upon the two extremes, the red and the
violet, in contrary directions to A, causes them to emerge
parallel, the condition of achromatism, when they converge
to the conjugate focus f, about 9 in. removed from B. The
spherical aberration is reduced to a minimum by the forms
of the lenses employed, i.e., ray Lr, refracted by the central
portions of the lenses, meets the axis at the same point f,
as the marginal rays, or nearly so. I have decided upon a
4-in. (effective) diameter condenser, since it fully illumi-
nates the corners of a 2|-in. square slide. Of course, a
circular slide of 3 in. only requires a 3J-in. diameter con-
denser, of proportionately shorter focal length. I need
hardly say that the glass composing this condenser has
been selected with especial care. It is perfectly limpid, or
colourless, and will remain so ; it is free from stricB and air
bubbles, and has a perfect polish. In fact, it is Chance's
best glass ; the only drawback being its cost."
Mr. Dallmeyer goes on to remark that the defects in the
glass of a lantern condenser, are of far more importance than
similar defects in the objective, so far as purity and quality
of the illuminated disc are concerned. He refers to such
defects as scratches, air-bubbles, and the like. In the case
of an air-bubble in the objective lens, it is really of no
moment whatever. I have known of a photographic lens,
otherwise of splendid quality, being rejected because of
a tiny air-bubble near its margin, the purchaser being quite
content to exchange it for a far inferior lens without such
an insignificant blemish. Such a bubble would have no
THE BOOK OF THE LANTERN. 25
effect whatever upon the performance of the lens, whether
used with a camera, or as a lantern objective, supposing it
to be suitable to lantern work in other respects. But
transfer the bubble from the objective to the condenser, and
it at once constitutes a real eyesore, which will be terribly
magnified on the screen. For this reason lantern owners
should take the greatest care to prevent their condensers
becoming scratched, for a mark hardly visible on the glass
will become fatally apparent on the screen.
It will be seen, from what has gone before, that the duty
of the condensing lens is to take up and utilise as large a
bundle of light rays as is practicable, and with those rays to
brightly illuminate the whole of the picture or slide placed
against it. The other part of the optical system of the
lantern is the objective lens, which is destined to
form a magnified image of that picture or slide. To this
important part of the apparatus I must now turn the
As the duty of the condenser is to give the greatest
amount of illumination to the lantern picture or slide, so
the province of the objective lens is to form as perfect as
possible a magnified image of that picture upon the screen
or sheet placed for its reception. Toy lanterns are fre-
quently fitted with a double convex, the worst form of all,
or with a plain convex lens, which is little better. With
regard to lanterns of more pretension, we find that different
makers adopt different forms and combinations for their
objectives. Some use a couple of plano-convex achromatic
lenses, in conjunction with a stop or diaphragm, the flat
sides of the lenses being next the light ; a very
26 THE BOOK OF THE LANTERN.
good form indeed, provided that the lenses are of sufficient
diameter to take in the entire cone of rays from the con-
denser. This has always been a stumbling-block in
adjusting lenses of short focus to the lantern, for it stands
to reason that the shorter the focus the nearer must the
lens be to the condenser, and if the diameter of the
lens be small a large proportion of the rays will not get
through at all.
And this question of focus of the objective is one that
must be carefully considered by all who use a lantern.
Many are of the opinion that the focal length of the objec-
tive used should be so short that the distance of the
lantern from the screen should be about the same as the
diameter of that screen. In private rooms of small size
this may be necessary, if not advantageous, but in larger
rooms or lecture-halls a lens which will triple or quadruple
that distance is desirable. Much experience of lecture-
hall work has led me to the conclusion that a lens of 8-inch
focus is more useful as a lantern objective than any other,
and it is as well to have one of 10 inches in reserve in
case the length of the hall should require it. Let me give
my reasons for this choice. I find that the size of sheet
most commonly required, in rooms used for lecture pur-
poses is 15 feet. Some rooms will take an 18-foot sheet, and
very few take a larger one than that. But the 1 5 -foot screen
is the one most in request. Now let us suppose the operator
has fitted to his lantern an objective of say 4|-inch focus.
To cover his 15 -foot screen he must plant his lantern less
than 20 feet from it, a distance which will land him in
the middle of the front seats. His apparatus will
THE BOOK OF THE LANTERN. 27
in sack a case terribly impede the view of all those
behind the lantern, besides causing much disarrange-
ment of chairs. But let him use an 8-inch objective,
and his lantern can he carried to a distance of
35 feet from the screen. This will probably place the
lantern quite at the back of the hall. Another point in
favour of the latter position is, that if his two lenses are of
the same diameter, as most probably they will be, the long,
focus lens will admit more light, as already explained ;
while it will certainly give better definition and less dis-
tortion jbhan the shorter focus lens. One more circum-
stance in favour of the longer focus lens is, that the lantern
is kept more horizontal. When the instrument is close to
the screen, unless the floor of the auditorium be inclined,
as in a proper lecture-theatre, the lantern must be very
much tipped up at its fore-end, so that the disc on the sheet
shall be high enough. This raising of the. lantern, of
course, leads to distortion, unless the screen be inclined
towards the lens so as to compromise the matter. With a
long-focus lens the distortion from this cause is greatly
reduced, and very often it is so slight that there is no need
to incline the sheet. I hold the opinion that a good single
achromatic lens of long focus is by no means to be despised
for lantern work, although a half-plate lens of the portrait
type is to be preferred. Such a lens can only be used for
the long-distance work. If it is absolutely necessary that
the lantern be as near the sheet as possible, then it is com-
monly the fashion to use a French quarter-plate photographic
lens, I presume on account of its cheapness. For it is
most difficult to select a lens of this description which will
28 THE BOOK OF THE LANTERN.
give a flat field, and the ordinary diameter of the back lens
of such a combination will not admit the whole of the
rays from the condenser : hence we are robbed of light,
and very often of the corners of square pictures into the
Of late years makers have seen these disadvantages, and
have produced lantern objectives which, while they are
similar in construction to portrait objectives, are made with
much larger apertures at the back. Taking Mr. Dallmeyer's
lantern objective as the prototype of these, we find that it
consists, like the portrait lens, of two combinations. The
back one, next the light, is a convexo-concave of flint, and
another of crown glass, separated by a short interval, the
two glasses being dissimilar in their curvature. The
external form of this combination is a meniscus, its convex
surface being next the condenser. The front combination,
of smaller diameter, also has the external meniscus form,
but consists, like its fellow, of two glasses.
It must be noted that objectives made for lantern work
are not suitable for photography, for the visual and chemical
rays are not coincident. I mention this for the sake of
those who wish to use the lantern as an aid to their photo-
graphic pursuits, in enlarging and so on. It may^theref ore,
be in some cases desirable for the purchaser to obtain a
half -plate portrait lens for his lantern. It will do excellent
work, with the limitation already referred to, while at the
same time it can be used either for portraiture or for
enlarging. For both these uses it is well adapted.
The rule for calculating the distance of the lantern from
the screen in order to obtain an image of a given size will
THE BOOK OF THE LANTERN. 29
be found on page 95, bat in practice I find it a convenient
thing to use a tape measure. Upon the circular case of
this measure I have certain figures to the effect that such
and such a lens requires a distance of so many feet to give
a 15 or 18 foot disc. The place of the sheet having been
decided upon, it is then easy enough to pay out the
required amount of tape, and to fix the position of the
OXYGEN GAS MAKING.
[HE first requisite for the lime-light is an adequate
quantity of oxygen gas, and this chapter will,
therefore, be devoted to the details of its manu-
facture, or rather its separation from those substances with
which, in nature, it is associated. For, although the most
abundant of all the elements, oxygen does not occur in
the uncombined state, and, therefore, the chemist has to
be at the pains of separating it from its various yoke-
fellows. There are several methods of obtaining this gas ;
the greater number of which, being only of experimental
interest, may be passed over.
The gas was originally discovered by Priestley in 1774,
and at about the same time, independently, by the Swedish
chemist, Scheele. Priestley obtained it by heating mer-
curic oxide in a flask, which substance, under such treat-
ment, breaks up into mercury vapour and oxygen gas.
Such a method is clearly out of the question, when several
feet of gas are required for the lime-light.
Another method, which is applicable when large quan-
tities of oxygen are wanted, and which has long been
THE BOOK OF THE LANTERN. 31
adopted on a commercial scale, depends upon the action of
cobalt on bleaching powder (Calcic hypochlorite). The
lime must be in the form of a concentrated solution, and
this is best brought about by mixing, say, one pound of
bleaching powder, which is commonly called chloride of
lime, with a quart of water. Stir this mixture and allow
it to remain for an hour. Now decant the clear liquid,
and pour it upon a fresh pound of lime stir as before,
and strain the product through a calico or flannel bag.
Place the liquid in a large bottle, to the cork of which
a tube is fitted. Now drop into the liquid, taking the
cork out for the time being, a small quantity (say 2 ounces)
of a strong solution of cobaltic peroxide, when oxygen gas
will be quickly evolved, and will come off through the
replaced tube. The evolution of gas is increased by
warmth. The same cobalt can be used again and again, as
it does not undergo any permanent change. It seems to
act merely as a conveyer of oxygen, taking it from the
lime, passing it to a higher state of oxidation, and then
giving it up again ; any solution of cobalt will answer the
purpose. When the gas ceases to come, the residue in the
bottle should be diluted with water, and, after having been
allowed to rest for some time, the cobalt will settle at the
bottom of the vessel. This can then be washed, kept in a
moist state, and used over again as often as required.
But the more general method of preparing the gas is by
means of the decomposition of potassic chlorate, and
that method I shall now, therefore, describe in detail.
The lime-light has, in certain quarters, earned the cha-
racter of being dangerous, not so much from accidents
THE BOOK OF THE LANTERN.
which have occurred during its use, but more from certain
catastrophes which have taken place during the preli-
minary operation of making oxygen gas. There should be
no danger whatever about this operation if only ordinary
precautions are taken. But some people seem to be unable
to do things except in a haphazard manner, and they
sooner or later pay the penalty for their carelessness.
The most important point to begin with is to have
proper apparatus ; and by this I do not mean the most ex-
pensive, for this is just as often as not faulty in point of
construction. The articles required are : A retort in
which to generate the gas; a stove for heating that retort
(preferably a gas ring-burner) ; a wash bottle, or purifier ;
THE BOOK OF THE LANTERN. 33
several feet of good rubber tubing ; and a bag to hold the
gas when made. The retort which I prefer is Oakley's
pattern, and is made of wrought iron, brazed and rivetted
together, and of the form shown in the accompanying
sketch, fig. 16. It will be noticed that it is of conical form,
and that its lower part, where it rests on the stove, is con-
vex in shape. It terminates at the mouth with a brass
screw, and in this screw fits a branch, or pipe, which con-
veys the gas away as fast as it is generated. An important
point in this branch is the arched bend, immediately over
the retort, which obviates undue friction, and also prevents
any solid particles given off from the retort clogging or
stopping up the tube. With that provision one element
of danger is avoided. Another point of importance is the
little upright tube, or nozzle, immediately above that same
bend. This is merely a short piece of tubing fixed on to
the branch, and in which a cork can be fitted. This acts
as a simple safety-valve. Should the pressure of gas
become too great, the cork will fly out and no damage can
possibly occur, except the loss of a very small quantity
There are various other forms of retort which are used
and recommended by different operators. A cast-iron one
is, of course, more lasting ; but in case of accidental explo-
sion, its particles would be as deadly as those of a bomb-
shell. But such an explosion should never occur, if
ordinary care be taken. With some persons, familiarity
with the most dangerous agents so rapidly breeds con-
tempt, that they get careless in a very short time. We
may suppose that this happened in the case of an optician,
34 THE BOOK OF THE LANTERN.
who some years ago was killed by such an explosion of an
Many old-fashioned operators use an iron mercury
bottle as a retort, and this, I believe, was the invariable
custom when oxygen was procured from manganese per-
oxide alone. The heat required was so great that a thick
and lasting receptacle was necessary. But now-a-days,
when chlorate is used so universally, the gas comes off at a
much-reduced temperature, and a thin retort will last, with
care, for about fifty charges. My lantern assistant prefers
to use a kitchen digester, which he has had fitted with
a pipe and safety cap, and which he regards as a triumph
of art, which will not only last his own life-time, but will
be handed down to his descendants as an heir-loom. One
more word on the subject of retorts. Do not buy a copper
one ; it is very expensive, and quickly wears out, and has
no advantages whatever. In case a retort should be
wanted in a hurry, and cannot be obtained, a common
cast-iron kettle is a capital substitute for one. Put the
chlorate mixture in the kettle, and fasten on the lid with
a luting of white lead or clay ; cut a piece of firewood
to the correct size, to fit tightly between the lid and
the inside of the handle of the kettle, so that no pressure
will force it open. Use the spout as a delivery tube of the
The retort is charged with a mixture of chlorate of potash
and oxide of manganese, and the most usual proportions
are four parts by weight of the potash to one part of the
This is the mixture as given in the various chemical text-
THE BOOK OF THE LANTERN. 35
books ; but, as a matter of fact, the exact proportion is not
of very great consequence. Indeed, it would seem that if
the crystals of potash have mixed with them just sufficient
of the black manganese to dirty them well, the mixture
will be effective.
Oxygen gas can be generated from the chlorate alone,
but the action is so uncertain that the salt is always mixed
with manganese, oxide of iron, or sand. What action the
manganese has upon the mixture is not known, for it is
a curious fact that, after the operation is over, it remains
unchanged, so that it is possible, if one cared to take the
trouble, to preserve it and use it over and over again.
Where manganese is difficult to obtain, this method may
be adopted, but in most towns it can be procured at such
a cheap rate that such a course would simply represent a
waste of time and trouble.
The greatest care should be exercised in procuring both
components of the oxygen mixture in an unadulterated
state. The ordinary commercial chlorate is quite good
enough for the purpose, and although it has the disadvan-
tage of being contaminated with a certain amount of free
chlorine which is given off in gas-making, it would be
a useless expense to employ the pure salt, as used for
medicinal purposes. Moreover, the chlorine can be got rid
of, as we shall presently see, by simple means. But in
most samples of commercial chlorate there are to be found
certain foreign bodies, such as bits of straw, bits of wood
(from the casks in which the chlorate is originally sold),
and other specimens of matter in the wrong place, which
would be prejudicial to the operation of gas-making, and,
36 THE BOOK OF THE LANTERN.
indeed, dangerous ; for carbonaceous material, when mixed
with, the chlorate, constitutes a very powerful explosive.
(As an instance of this, I may mention that in the greatest
explosion of modern times, when thousands of tons of
explosive material were fired for the purpose of destroying
the "Hell-Gate Bock" at the entrance of New York
Harbour, a large proportion of the chemicals employed
consisted of chlorate of potash combined with coal-dust.)
Before mixing the ingredients together, therefore, the
crystals of potash should be carefully picked over by hand,
and any unconsidered trifles which have no business to be
present should be carefully extracted from it. A little care
is also necessary with regard to the manganese. Accidents
have happened from lampblack, bone-dust, and other similar
compounds, having been substituted (let us hope by acci-
dent) for the manganese that was intended to be used. In
buying fresh samples, therefore, of manganese, it should
be carefully tested, and the best way of doing this is to mix
up a small quantity of the potash and the manganese in
the proportions above given, and to put them in a test
tube, which should be held over the flame of a spirit lamp.
If the mixture simply sparkles while oxygen gas is given
off at the mouth of the tu-be (as may be tested by the spark
on a blown-out match), the mixture is safe ; but if any-
thing in the least resembling an explosion should take place,
the manganese is wrong, and must be rejected. But the
operator is not liable to fall into the error of mistaking
lampblack or bone-dust for manganese, because they are,
bulk for bulk, so very much lighter than that heavy
THE BOOK OF THE LANTERN.
The mixture having been made, enough of it must be
placed in the retort to give the amount of gas which we
require. It will be found that if we allow one pound of
chlorate to every 4 feet of gas, it will be about right.
Roughly speaking, a bag of 8 feet capacity, a very useful
size, will take 2J Ib. of the mixture, and it is better to
waste a little chlorate than to have a bag which is not
quite full. Having charged the retort with the mixture,
we can screw on the delivery branch, taking care to insert
a washer of leather or asbestos cloth, to prevent any escape
of gas between branch and retort.
In using a new retort, it is always well to blow
into it while the branch is fixed in position, so as to be
quite sure that there is no leak in the joints which has
escaped the maker's attention. Should a
leak be discovered, a little white lead will
remedy it for the time being. The retort
may now be placed on the gas-stove, while
its branch rests upon a chair or other
support. A tube at least 4 feet long, and
of a diameter agreeing with that of the
branch of the retort, should be drawn
over that branch for about 2 inches. The
other end of this tube is to be connected
with the wash-bottle.
The kind of wash bottle which I
use, and which I can recommend very
highly, is also made by Oakley & Co. Fl . 17.
of Bermondsey (fig. 17). It is of half a gallon
capacity, and is in reality a glass "Winchester quart"
THE BOOK OF THE LANTERN.
bottle with a wide neck, such as can be obtained anywhere.
Upon this neck fits a disc of lead, perforated with two holes,
in which are soldered as fixtures two pewter tubes which
bend away from one another at their tops.
One tube, A, reaches nearly to the bottom of the bottle,
and it will be seen that for several inches along its lower
part it is perforated with holes. It is this tube which is
connected by a rubber pipe to the retort. The dotted
line shows the height to which the bottle must be filled
with water. The short tube, B, is the delivery tube of
the bottle, and is connected with the gas bag. As a gas-
tight connexion between the pewter disc and the bottle,
there is a thick rubber collar, which is tied on the bottle
by means of a piece of strong twine. The larger sectional
diagram of the bottle neck (see fig. 18) will assist the
reader in noting the arrangements described. In order to
prevent any chance of water being thrown up into the gas
bag, it is as well to place the bag on a table. Let us sup-
THE BOOK OF THE LANTERN. 39
pose that this has been done, and that everything is ready
for making the gas.
The stove should be lighted and turned down almost to
its lowest point, for it is as well to begin with a small
amount of heat, although I believe that it is the practice
of some workers to begin with a full heat, and to turn the
supply down when gas commences to come off. The tube
is joined to the retort and to the wash bottle ; but the
tube joined to the delivery end of the bottle is for the
present left free at its other end. After an interval of
about five or six minutes, the water in the wash bottle
should show by its bubbling that the gas is being generated,
but those bubbles are not as yet pure gas, but are partly
air which has been contained in the retort, and which is
expanded and driven out by the heat. We must wait
some time longer, until these bubbles are given off
with regularity, before attempting to fasten the open
tube to the gas bag ; and before doing so it is as well
to apply the test of the blown-out match to the free end of
the rubber tube. If the spark on the match bursts into
flame directly it is applied to the tube, we may be sure that
gas is coming off in earnest, and we can by a dexterous
movement fasten the tube on the tap of the gas bag, at the
same time turning on that tap.
Everything should now go on with regularity and with-
out attention, until the bag is nearly half full. During
this time it may be noticed that the tube leading from the
retort will emit a kind of bubbling noise. This is due to
water lodging there which comes from the crystals of
potash in the retort. By simply lifting this tube up, and
40 THE BOOK OP THE LANTERN.
by giving it a gentle pinch for half a second the sudden
ontrush of gas into the wash bottle will drive off any water
that has settled there. When the bag is half full there is
gene^a-Py a lull in the operation, and no bubbles are seen
he water in the wash bottle ; and this opportunity
may ^ssnoaken for turning on a little more gas, but not
much more, for presently the oxygen will run off with
redoubled vehemence, and if too much flame is applied to
the retort the pressure may become too great for the con-
nexions, or the cork of the safety valve may fly out. By
governing the amount of gas supplied to the stove, the
emission of oxygen can be very carefully regulated. (This
regulation becomes still easier if a certain amount of
common salt be added to the gas mixture in the retort.
This should be done just before the retort is charged. The
proportions are as follows :
Chlorate of potash ... ... ... 8 parts
Manganese ... ... ... ... 2
Common salt ... .., ... ... 1J
all by weight. When common salt is thus added to the
gas mixture, the chlorate should be powdered.)
When the gas bag is full: and " as tight as a drum," the
various parts of the apparatus used in making the gas
must be disconnected, and here some caution is necessary.
The first thing to do is to pull the tube from the gas bag
and turn off the tap at the same instant. Next remove
the tube from the retort, and last of all turn off the gas
supply from the stove. Why I say that caution is necessary
here, is, because if the gas is turned off before the retort is
THE BOOK OF THE LANTERN. 41
disconnected from the wash bottle, the water in the latter
may rush back into the retort and cause a small steam
This has certainly never happened to me ; but I b^ve
heard of cases where such a thing has occu: 1
although it would probably be unattended by any id 1 1 tous
results, it might lead to a great deal of mess and
The retort may be left, until it has become nearly cold,
or at any rate until it is cool enough to be handled. The
branch pipe should then be unscrewed, and the retort at
once washed out with water warm water by preference.
This should be thoroughly done, and many changes of water
should be used, until the last wash water comes away per-
fectly clean. If the retort is left with the residue of the gas
mixture in it, the metal inside is very quickly corroded, and
the vessel does not last half so long as it does if it be at
once carefully washed. The branch and the india-rubber
connecting tubes should be washed out also.
I have mentioned that* the commercial chlorate of potash
is contaminated with a certain amount of free chlorine. This
soon renders itself evident if the operator places his nose
near the delivery tube from the wash bottle when the gas
is coming off; for chlorine gas has a suffocating odour.
This is not the only disadvantage which it has in gas
making for lantern purposes, for it so acts upon the india-
rubber bag and the attached brass work that it quickly
leads to deterioration. By placing in the wash bottle
water something which will seize hold of this chlorine and
detain it, we shall avoid this last difficulty, and the
42 THE BOOK OF THE LANTERN.
best substance for the purpose is caustic soda, or
potash, Failing this, common washing soda will answer
nearly as well. Caustic soda is rather an awkward thing
to travel about with, for it is of a most corrosive nature ;
but it should be used in preference to anything else, when
gas is made at home. Fragments of disused lime cylinders
will also answer well.
To show that the chlorine is actually taken up by the
bag and its belongings, I may mention that if the experi-
ment be tried it will be found that the gas when first made,
although highly charged with chlorine and inducing
coughing and other unpleasant sensations if inhaled, may,
after having been left in the bag for an hour or two, be
breathed without any ill effect.
Mr. Fleuss, whose diving and life-saving apparatus de-
pends in a great measure upon a supply of compressed
oxygen gas, called my attention to the above fact, and told
me that he had used gas for breathing purposes which had
been freed of its chlorine by remaining in the gas bag for
some hours as I have just explained.
I may mention that the residue left in the retort and
which I have recommended, should be washed out without
delay, consists of chloride of potash, and the manganese ;
the latter quite unaltered. It may be useful to point out
that the difference between the chlorate and the chloride is
easily seen by examining the crystals of each under a
microscope. If a little chlorate mingled with water is
placed on a slip of glass, and allowed to evaporate, the
crystals will have a rhombic form (see A, fig. 19). But if, on
the other hand, a solution of chloride of potash be examined
THE BOOK OF THE LANTERN.
in the same manner, they will be found to be square in out-
line, as in B. Should it be desired to use the manganese
over again, it must be freed from the chloride by repeated
changes of water. It will thus be dissolved out, while the
manganese remains behind in the form of black mud.
This latter must be dried before being again employed in
The operation of oxygen gas making is now with many
lanternists a thing of the past, for they prefer to buy it
ready made. For many years this gas has been supplied,
by one or two makers, compressed in iron or steel
cylinders. But the price, eightpence per foot, was too
high to induce consumers to relinquish the custom of
making it themselves. Of recent months, however, the
gas has been supplied at half that price, with the result that
many prefer to buy it rather than make it themselves.
The manufacture of oxygen gas therefore represents "A
curious new industry," and under that title I described it a
44 THE BOOK OF THE LANTERN.
short time ago in an article in " Chambers's Journal." From
that article I will now give the following extract :
" Any manual of chemistry will inform us that oxygen
is the most widely-diffused element in nature. It enters
into the composition of air, of water ; it is found in nearly
all earths and rocks; and forms more than one half of
animal and plant life. In fact it is not too much to say
that oxygen forms one-half of the globe and its belongings ;
but of course it is combined with other elements. Chemists
can tell us of a dozen different methods of isolating this
gas ; but the one most usually adopted is to'subject a salt of
potash (potassic chlorate), which is extremely rich in
oxygen, to heat in a retort, when it quickly parts with that
gas, which can be collected in a suitable containing vessel
for use. To show the extent to which this salt is used for the
production of oxygen, we may mention that we were lately
informed by a London dealer that he sold yearly one
hundred tons of potassic chlorate, and that he had reason to
believe that it was nearly all used for the production of gas.
This quantity of the salt would afford, roughly speaking,
nine hundred thousand cubic feet of oxygen, and we must
not forget that this is the amount dispensed through one
dealer only. The natural question which arises as to what
purposes this gas is applied, we shall deal with presently.
We have preferred to show, first, that there is an enormous
demand for oxygen, so that the importance of a new
industry for producing it may be at once appreciated.
" Oxygen forms one-fifth of the air which we breathe, the
other four-fifths consisting of an inert gas called nitrogen.
And it is important that we should remember that the
THE BOOK OF THE LANTERN". 45
mixture of these two gases is a strictly mechanical, not a
chemical one. What we mean is this. If it were possible
by any means to make visible and magnify the particles of
air, we should be able to distinguish the atoms of oxygen
and of nitrogen side by side, but in the proportion of one
to four. It might be compared to a mixture of pepper and
salt, which, although it looks gray to the unaided sight,
would, under the microscope, show plainly the independent
grains of both constitutents. (It is curious to note that a
chemical mixture of the two gases, in which their atoms
combine to form a new compound, produces that useful
anaesthetic, nitrous oxide laughing gas.) It has long
been the dream of chemists that oxygen might be produced
direct from the atmosphere by separating its atoms from
the atoms of nitrogen with which it is associated but not
combined. Indeed, a plan by which this could be accom-
plished has long been known, but it happens to be one of
those numerous method which in theory are perfect, but
which when reduced to practice are found to be encumbered
by various difficulties. But as a new industry is founded
upon the process referred to, and its success has been
assured by a patient conquest of the numerous practical
difficulties associated with it, we cannot do better than
" It was long ago demonstrated by Boussingault that when
the substance called baryta, otherwise the oxide of barium,
was heated to a low redness, it would absorb oxygen from
air submitted to it. He further showed that if this com-
pound were then raised to a higher temperature, the
oxygen thus absorbed would be given off once more, and the
46 THE BOOK OF THE LANTERN.
baryta would be restored to its former condition, ready
for a repetition of the action. It would thus seem that
there was at hand a process for obtaining from the atmo-
sphere an endless supply of its essence, so to speak. But
as we have before hinted, theory and practice are two
different things. The process would not work on a com-
mercial scale. All went well at first ; but for some reason
or other, the baryta lost its power of recovery, and would
not repeat its office of absorbing oxygen.
" A few years ago, two of M. Boussingault's pupils, Messrs.
A. and L. Brin, resolved to carry through a series of ex-
periments to find out, if possible, why in this case, practice
would not endorse theory. They soon found that the reason
why the baryta lost its power of absorbing oxygen was due
to certain molecular changes, which ceased to occur if
the air supplied was absolutely free from impurities, and if
the heat employed for reducing the baryta to its first
condition were kept within certain limits. They further
found that the necessary temperature might be much
reduced if the material were heated in a partial vacuum.
Another advantage was found in supplying the air under
pressure, in which case the absorption of oxygen from
it was much increased. These new conditions were speedily
realised in apparatus which was erected in Paris, and which
for three years yielded oxygen of the purest description
without any renewal of the baryta with which the retorts
were charged at the commencement of operations ; and this
apparatus was exhibited at the Inventions Exhibition at
South Kensington a few years ago.
" The process having thus been shown to be workable, the
inevitable Company was formed ; and oxygen can now be
THE BOOK OF THE LANTERN.
obtained in any quantity at a cheap rate by any one who
requires it. Erin's Oxygen Company has established ex-
tensive works at Westminster, where, by a system of
retorts and air-pumps, the business of abstracting oxygen
from the air is continuously carried on. The gas is carried
to a holder, in which it is stored ; and is drawn from that
holder and compressed in steel cylinders for the use of the
Company's customers. These cylinders are so strong, that
one having the capacity of little more than a cubic foot of
gas will hold forty feet when that gas is compressed within it.
These bottles, placed in wooden cases, are now sent over
the kingdom by rail and carrier."
The gas is of the utmost purity, and is largely used for
charging water for drinking purposes, as a remedy for
The following table gives the sizes of the cylinders
supplied, together with their length and weight :
SOLID DRAWN STEEL CYLINDERS CHARGED TO 120
THE BOOK OP THE LANTERN.
Low PRESSURE CYLINDERS CHARGED TO 10 ATMOSPHERES.
Each cylinder is fitted with a tap to regulate the flow
of gas, which tap has a nipple over which the rubber
tubing can readily be drawn. The
advantage of using a bottle instead of
a bag in the one point of bulk is re-
markable, as may be seen by the above
table. Thus, six cubic feet, which will
be sufficient for an hour and a half's
entertainment, is contained in a re-
ceptacle about the size of a champagne
bottle, and which can be placed in
the empty lantern-box during use.
The amount of gas in a bottle can be
readily ascertained by the use of a
proper pressure gauge. In fig. 20 one
of these cylinders is shown with the
regulator and pressure gauge attached.
The latter is of the form commonly
used on steam engines, and is known
as Bourdon's pressure gauge. It depends for its efficiency
on the action of internal pressure upon a curved tube of
oval section. The greater the pressure the straighter the
tube becomes, and this movement is communicated by
simple gearing to the index-finger. The following table
will be found useful to those who employ compressed gas :
THE BOOK OF THE LANTERN.
TABLE SHOWING THE AMOUNT OF GAS IN VARIOUS-SIZED
CYLINDERS, AS SHOWN BY GAUGE. THE GAUGE INDI-
CATION IS IN LARGE TYPE, AND THE CORRESPONDING
AMOUNT OF GAS IN SMALLER TYPE.
CAPACITY OF BOTTLES.
LIME-LIGHT JETS, BAGS, PRESSURE BOARDS, ETC.
HEBE are three forms of jets for the lime-light,
namely, the oxy calcium, the blow-through, or
safety form, and the mixed jet. The simplest
of all is the first named.
The oxy calcium jet consists of a spirit-lamp, which is
fed from a little reservoir at the back of the lantern. The
spirit furnishes the necessary hydrogen, and through its
flame a jet of oxygen is passed, and impinges upon a
cylinder of lime placed just at the other side of the wick.
This lamp will well illuminate a disc of about ten feet in
diameter with a clear, white light. It has the advantage
of simplicity, but presents one difficulty in the circum-
stance that the lantern must be kept perfectly level. If it
is inclined backwards, the spirit cannot flow to the point of
combustion, and if it -is inclined forwards the fluid may
flow too rapidly towards the wick. In some forms of
oxycalcium lamp this is obviated by a special construction
of the spirit cistern, which is furnished with an automatic
valve for governing the supply of fluid to the wick. The
wick will rapidly become charred if the stream of oxygen
THE BOOK OF THE LANTERN.
is allowed to impinge upon it; it should be so adjusted
that the gas just escapes touching it while passing through
its flame. This form of lamp is sometimes fitted with a
wick of asbestos, which well resists the greatest heat that
can be brought against it. The oxycalcium lamp is valu-
able where no hydrogen gas can be obtained, and, while
far more powerful than a mineral oil flame, can hardly be
considered sufficiently powerful for use in a public lecture
hall. It is used in many of the hospitals in conjunction
with a simple form of lantern for throwing light upon
patients during certain operations.
Before I reached the mature age of
twelve I had made oxygen gas by
nearly every available method, and had
used in this work sundry blacking
bottles, ginger-beer bottles, gun-barrels,
and gas-pipes, employing as gas-bags
disagreeable bladders fresh from the
butcher's. It is a wonder to me that
I was never blown skywards, but
blown-up in a figurative sense I often
was. It is now my turn to assume the
position of "stern parent," but in doing
so I soften towards the juvenile ex-
perimenter in memory of my own
misdeeds. Perhaps a description of
my first lime-light jet, made at
the cost of a few pence, of two FlG - 21 -
gasfitters' blowpipes, will answer the purpose better than
anything else, of demonstrating the principle of the ordi-
52 THE BOOK OF THE LANTERN.
nary blow -through, or safety jet, which, on the whole, is
the best form of burner for amateurs to adopt (see
A isja piece of wood rounded off at one side of its upper
end, as shown, so as to accommodate its form to the bent
blow-pipe, which is marked 0, for this pipe is the conveyer
of the oxygen. This is fixed in position by loops of wire,
passing through holes in the wooden support. Upon
the other side of this support is bound in like manner
another blow-pipe, which has its fine nozzle cut off. This is
marked H, for hydrogen, and is connected when in use
by means of an india-rubber tube, to the house-gas supply.
The upper points of these two pipes are so adjusted that
the oxygen gas will blow through the flame from the H
pipe, on to the lime cylinder L. A jet formed on this
principle has the word " safety " linked to it, because the
two gases are kept quite separate until they meet at the
point of com bustion. Singly, they are innocent of harm ;
but mixed, except under certain precautions, as we shall
presently see, they form an explosive compound second
only to gunpowder.
To say that the arrangement thus described and illus-
trated is anything but faulty in construction would be
absurd, but I will say that there are many jets sold of
far more pretension which give no better light, and cost
as many florins as this one does pence. But as I have
said, I have described it as a ready means of explaining the
principle of the blow-through jet. I have tried many
different patterns of jets, and have selected the one illus-
THE BOOK OF THE LANTERN.
trated at fig. 22 as being by far the most perfect of any of
the blow-through type.
In selecting such a jet the buyer should be carefal to
see that the orifice of the O pipe is sunk within that which
supplies the hydrogen, as shown at M. In many jets the
two pipes are brought to the same level, but the form I
54 THE BOOK OF THE LANTEKN.
illustrate gives a much better light, probably because the
two gases are better mixed before reaching the lime. L is
the pin upon which the bored lime cylinder rests, and it
can be moved to or from the jet by means of the shifting
screw S. K is a rod which extends outside the lantern,
and which is for the purpose of turning the lime cylinder.
The form shown is one commonly met with, and it consists
of a rod connected with a bent spiral of wire. I have
long ago discarded this arrangement, as it works by fitful
starts, and jerks the lime round instead of moving it by
degrees. The form of lime-turner attached to the jet
shown at fig. 23 is the one to select.
This form is known as the mixed jet, by which the most
powerful form of lime-light is obtainable, but, as already
pointed out, it is not so suitable as the one before described
for amateur use. Both gases must be under the same
pressure, therefore two bags for and H respectively
must be employed, usually under the same pressure boards.
The jet is safe enough in skilled hands, but is not so,
unless care be taken with every detail. The two gases
are led to the box or chamber W, where they mix, and
impinge upon the lime through the single jet J. D repre-
sents a recent improvement which I believe was first
suggested by that very good authority on lantern matters,
Mr. Lewis Wright ; it deals with the manner of turning
the lime cylinder, so that it may not become pitted by the
continued action of the jet upon one spot. The primitive
plan was to open the lantern door at frequent intervals,
and to give the hot lime a hasty touch with the finger.
Next the lime pin was furnished with a screw which could be
THE BOOK OF THE LANTERN. 55
worked outside the lantern, so that it was turned and raised
by the same action. But, strange to say, the screw was of
so fine a pitch, as in fig. 22, that by one revolution the
pitted part of the lime was once more brought under the
influence of the jet. In Mr. Wright's arrangement, which
I have long ago adopted, the screw is a spiral, which
during one revolution raises the lime quite a quarter of an
inch. This plan has still further been improved upon by
the addition of a nicked wheel, which prevents the lime
being turned by the operator more than is necessary for
the time being. This addition is known as " Newton's
Improved Check-action Lime-movement." The same firm
of opticians have carried out a still further improve-
ment devised by Mr. Andrew Pringle. This consists
of what is called a " cut off," and is applicable only to
the mixed gas jet. It gives the operator the means of
setting his jet so that the gases are giving the best pos-
sible light, and then by the turn of an extra tap cutting
them off, with the exception of a small supply of the
hydrogen which keeps burning. He can, therefore, adjust
his lights beforehand, and feel confident that a turn of
the tap will once more render them at their best at a
There is certainly room for improvement in the manner
in which lime jets generally are supported in the lantern.
A metal tray, sliding in grooves, forms a base board, at the
end of which is an upright rod of iron which, during use,
projects at the back of the lantern. Upon this vertical
rod the whole jet can be moved up or down, and can be
clamped in position by means of a couple of screws, witli
THE BOOK OF THE LANTERN.
milled heads. The arrangement is by no means a good
one, but it is one of those simple things which have been
unheeded by the many, and manufacturers generally have
adopted it without perhaps thinking how inconvenient it is
in practice. In the first place, the jet is apt to slip either
downwards bodily, or to one side or the other by a careless
touch of the operator's hand. In either case, such a shift-
ing of the light out of the optical axis causes the disc to be
darkened until the jet be readjusted, which cannot be
easily done without opening the door of the lantern and
letting out a flood of light in the darkened room. There is,
besides, much trouble in getting the jet central, which could
easily be avoided by a more rational arrangement. Mr.
Pumphrey, of Birmingham, has devised for the purpose a
horizontal and vertical rack motion, very like the same
movement which is attached to the mechanical stage
of a microscope, but it is somewhat expensive, and
adds extra weight to the lantern. There is no doubt,
at the same time, of its effectiveness and conveni-
THE BOOK OF THE LANTERN. 57
ence. A simpler plan is that recently introduced by Mr.
Steward, and shown at fig. 24. In this case a tongue of
metal is fixed to the supply pipes of the jet, and this
tongue has a slot in its centre, which engages a vertical
pin on the lantern tray. This pin is threaded so that a
couple of discs can firmly clamp the metal tongue when
the jet has been once centered. Once clamped in this
way, the jet cannot be moved until it is released by
unscrewing the discs.
Another valuable improvement is represented by Wood's
lime cylinder shield, which is shown, fitted to a jet, at
fig. 25. It consists of a metal cylinder, rather larger than
the lime, in which the latter is free to turn. There
is an opening in front, through which the incandescent
lime can throw its light towards the condensing lens.
In jets, generally, the lime is quite exposed, and unless it
be gradually heated will often crack to pieces, by the
THE BOOK OF THE LANTERN.
unequal expansion which it undergoes. The shield pre-
vents this by confining the heat within a narrow area
around it, at the same time keeping the lantern itself com-
paratively cool. Mr. Wood tells me that there is an
undoubted gain of light from this conservation of heat in
and around the lime cylinder. The shield, moreover, does
much to obviate a by no means uncommon accident,
namely, the fracture of the valuable condenser itself from
a flame deflected towards it from a cracked or much-pitted
The most general method of storing the gases required
for the lime -light is by means of bags, which should be of
the best quality. It is necessary to caution the beginner
on this point, for I have known cases where a perfectly
new bag, fresh from the maker, has been found, on trial,
to leak badly. I cannot say that such an unpleasant cir-
cumstance has happened to myself, for I go to a maker
upon whom I can rely. It may possibly have been the
fault of the operator himself, who did not take the pre-
caution to warm the bag before use. For these bags in
winter time when of course they are most generally used
get stiff and hard, and if not of good quality are apt
to crack, unless carefully warmed before use.
The best bags are made of unvulcanised rubber, covered
on the outer side with twill, and on the inner side with coarse
canvas. This rough canvas serves a double purpose it
gives strength to the bag and also prevents the inner sides
sticking together when the bag is empty. After a bag has
been in use some time, the presence of this canvas makes
itself evident by a quantity of fibrous matter which
THE BOOK OF THE LANTERN. 59
comes out of the jet, and which I have been gravely told
by an ignorant operator is a deposit left by the oxygen
The bag is furnished with a brass stop-cock, which is
apt to get so stiff as to be very difficult to turn. For this
reason the screw holding the plug of the tap should be
undone frequently, and the plug touched with a little oil,
vaseline, or tallow. This stiffness is due to free chlorine,
which, as is explained in the chapter on oxygen making,
is often present in that gas. The purchaser of a bag is of
course to a great extent at the mercy of the trader, and
many inferior bags are sold to the unwary. But a few
inquiries among those who know what a good bag should
consist of will soon inform the buyer where he can pur-
chase one which is reliable in quality. Certainly too rigid
an economy should not be exercised in this particular part
of the lantern equipment.
The gas-bags are made wedge-shaped so that they
can be placed between sloping pressure boards fur-
nished with weights. I have heard of careless operators
who are content to trust to luck for finding suitable
boards for their gas-bag, or bags, when they arrive at the
scene of operations. This is, of course, a most repre-
hensible proceeding. But should an exhibitor be so placed
that he cannot obtain boards, a blackboard, such as can
be found in any schoolroom, can be used for the purpose,
provided that it is fastened by staples to the floor. It
must also have a shelf at the other end, on its upper side,
against which the weights can rest. This is but a make-
shift, and one which should only be resorted to in an
60 THE BOOK OF THE LANTERN.
emergency. In some of my experimental lectures, where
I require a lime-light for occasional use on the plat-
form, I carry with me a small bag holding only three feet
of gas, and a special form of pressure board which I have
designed for the purpose. It consists simply of two pieces
of inch board, each pierced on one edge with corresponding
centre-bit holes three-quarters of an inch in diameter-
Into these holes fit half a dozen round rods of pine. A
couple of pieces of wood screwed to the under edge of one
of these pieces of board serve as a support to the twenty-
eight-pound weight employed. The lower part of this
skeleton pressure board is furnished with a couple of bolts
which shoot out, and into two screw eyes, fastened to the
floor. The whole arrangement will be rendered clear by
the annexed sketch (fig. 26). I merely describe it here in
the hope that it may be as useful to others as it has been
THE BOOK OF THE LANTERN. 61
For the blow-through jet only one pressure board is
required, and perhaps a better form cannot be used than
a couple of thin boards hinged together with a simple
ledge, or shelf, above, also on hinges, for the reception of
the weights. But for the mixed jet another arrangement
is necessary. In this latter case the two gases must be
under equal pressure. Two pairs of boards, like those
just described, may be used side by side, but they will
occupy a great deal of space, and a double supply of
weights will become necessary. This last objection is,
perhaps, more cogent than the first, for in these days of
patent weighing machines the old-fashioned 56-pounders
are becoming quite scarce. It is, therefore, much better
to use a pair of boards, so constructed that they will
embrace both bags one set of weights being all-sufficient
for the two. A further advantage of this arrangement is
that both bags are under the same pressure, and additional
weights put on during performance cannot affect one bag
to the prejudice of the other. Dangerous accidents have
before now happened when independent pressure boards
have been in use, from the weights having been in-
advertently shifted from one gas, while the other has been
left under full pressure.
To Mr. Maiden is due the credit of having first designed
a pair of pressure boards which would hold both bags
under one set of weights, and the arrangement which he
suggested is that which is now commonly adopted by
opticians, and figured in their catalogues. I myself
use a modified form of these pressure boards, and
as I have given much thought to the subject before
THE BOOK OF THE LANTERN.
having them constructed, and as they answer their purpose
most perfectly, I will describe them.
They are what are called skeleton-boards ; that is to
say, they consist of frames filled in with sail-cloth. This
mode of construction saves a great amount of weight.
The wood- work is of best pine, 1J inches thick, and is
mortised at every joint. Referring to fig. 27, it will be
seen that the upper frame is furnished with a couple of
hinged shelves, between which the weights are placed.
These shelves are made of hard wood, so that they will
not readily break. The lower frame (fig. 28) has let into it
a smaller frame, which, when the boards are not in use, is
bolted into the main frame for travelling. But when in
use, this lower frame is caused to fall downwards, so that
it acts as a support for the pressure-boards, keeping them
at the right angle. The hinges which connect the two
THE BOOK OF THE LANTERN. 63
frames together are of wrought iron and of very solid
construction ; for they have to bear some amount of strain.
It will be noticed that the sail-cloth is made in two pieces,
with eyelet holes along the edges where they meet, so that
by means of strong cord they can be laced up and rendered
as tight as a drumhead.
Between the two frames there is secured a sheet of sail-
cloth, which is nailed down to the lower board at the
hinged end. In the centre of its other extremity is sewn
a flattened ring of galvanised iron. Where the sail-cloth
is nailed to the woodwork zinc roofing nails should be
used, for they will never rust. To the end of the
lower frame which is farthest away from the hinges
is nailed a strong leather strap, about six feet long, and
when the bags are in position this strap is passed through
the flattened ring on the midway sheet of sail-cloth, and
then through a corresponding opening on the upper frame,
where it is secured with a buckle. By means of this strap
the two bags are kept in place, while the sail-cloth sheet
between them also helps to prevent them slipping back-
It is customary to place the hydrogen bag below and the
oxygen one above, but I am not aware that there is any
advantage in so doing. Certainly I have met with operators
who prefer to reverse their positions, and seemingly without
The taps on the bags should have a large bore, and the
tubes which serve to connect them with the lantern should
also be of good size. The amount of weight on the
bags is governed to some extent by the size of disc re-
64 THE BOOK OF THE LANTERN.
quired to be shown. Using a disc of from 15 to 18 feet in
diameter the exhibitor will do well to commence when the
bags are full with two half -hundred weights on his pressure
boards. But when the gas has been so much used that the
upper board gets nearly horizontal the pressure will be
lessened, and the light will suffer to some extent. When
this happens, the experienced operator will place another
half-hundredweight in position, and the increased bright-
ness of the picture will quickly show the advantage of so
When the gas or gases are drawn direct from steel
cylinders, or bottles, if a double or triple lantern is in
use, some form of regulator must be employed. The first
introduced, and perhaps the most perfect, is that patented
by Messrs. Oakley & Beard.
Before proceeding to describe this important new de-
parture in lantern working, it may be as well to point out
one or two difficulties which are incidental to the ordinary
method of storing the gases required in india-rubber bags.
So far as the writer knows, one of these difficulties has
never been recognised in print. This difficulty is com-
prised in the fact that any kind of gas, if kept in an india-
rubber bag, quickly deteriorates. By the phenomenon
known by the term endosmose, two gases separated by a
porous diaphragm will effect a mutual exchange. Take
the case of an ordinary india-rubber tube used. for a table
lamp or gas stove. How quickly it begins to smell.
This is nothing else but the gas escaping through the
india-rubber, and carrying on an exchange with that other
gas the air which is outside. It would be interesting
THE BOOK OP THE LANTERN. 65
to know how quickly this exchange takes place in the case
of a bag of oxygen; but, as an experienced worker, I
have no hesitation in saying that there is a marked
deterioration in the quality of the lime-light, if the oxygen
gas used has been kept for only 24 hours in a bag
instead of being freshly made. The same rule will
apply to the hydrogen gas in a greater degree, for the
hydrogen passes through a porous diaphragm far more
rapidly than can oxygen. But, in practice, the H bag is
filled from the nearest gas-tap immediately before it is
wanted. (Mr. Fletcher, of Warrington, has patented a
method of preventing the smell of gas-tubes, by inserting
a partition of tinfoil between the two layers of india-rubber
which compose the tube. This foil stops the smell, by
stopping endosinose. The same principle might, of course,,
be applied to gas-bags. Here is a hint for manufacturers.)
Other objections to the use of gas-bags are found in their
initial expense, and the necessity for constant renewal,
their bulk, and their liability to mechanical injury. In
spite of these defects, I have always preferred to use gas
in bags, rather than gas compressed in cylinders. My
reasons for this choice I will now give.
If the gases are compressed in cylinders, there is a
great saving in trouble, as well as in bulk of apparatus ;
but I have hitherto set my face against them for the
following reasons: 1. The pressure is so great, that the
india-rubber tubes are apt to blow off ; and, if tied on, may
burst. 2. The light cannot be regulated at the jets and
by the taps provided for that purpose, but the taps must
be turned fully on, and the outrush of gas roughly
66 THE BOOK OF THE LANTERN.
regulated a very difficult matter by the screw plug on
the nozzles of the bottles. 3. The operator at the lantern,
even if he succeed in thus procuring the delivery of the
proper amount of oxygen and hydrogen respectively, must
stoop down to do so, and, for the time, neglect other duties.
4. The pressure is constant ; and, therefore, if a double or
treble light is suddenly wanted as in the case of biunial
and triple lanterns the amount of gas measured out for one
light, must serve for two or three, as the case may be
and all suffer. 5. As the bottles gradually empty, the
pressure sinks ; and, therefore, the screw-plugs have to be
opened several times during an evening's work. Every
time this becomes necessary, there is a likely chance of too
much being turned on, and the tubes being blown off. It
is, therefore, seen that, although bags are troublesome,
bottles possess many disadvantages which would make any
careful operator pause before he adopted them. These
disadvantages, however, entirely disappear when the
bottles are used with regulators.
The action of the regulator can be understood without
much difficulty by reference to the annexed sectional
diagram, fig. 28. The screw-thread d* at the bottom of the
drawing, is where the casting D fits upou the bottle of
compressed gas ; d l is the delivery tube, governed by the
stop-cock d 2 . B is a base-plate supporting the most im-
portant part of the apparatus, and E E standing upon it
is merely a casing to protect the enclosed part from injury.
A A are bellows made of the finest rubber, and of a form
not unlike the bellows of a camera, only that it is circular.
The top of the bellows is heavily weighted, jso that its
THE BOOK OF THE LANTERN.
natural tendency is to remain compressed. This top is
furnished with a collar O l , having a screw-thread in which
the screw pillar F can easily turn. It will be noticed
that the thread of the screw is coarse, so we may call
it an Archimedean screw. At its lower part is a fine, and
therefore slow-motion screw, which works in the collar c.
Now, let us see how beautifully this double-screw motion is
applied to regulating the delivery of the highly-compressed
gas. As soon as the gas emerges from the bottle it passes
68 THE BOOK OF THE LANTERN.
between the space which is open between the valve/* and
the valve seat d. It then rushes into the bellows above,
which become gradually raised by its pressure. As the
bellows rise the screw pillar F is quickly turned in its
socket, and gives a slow motion to the screw below. The
effect of this movement is to bring the valve f down on its
seat d) and the supply of gas is cut off. But in practice
the gas will be drawn off from the delivery tube d l so
that the bellows will soon be compressed once more. As
the bellows move downwards, the screw F acts in the reverse
manner, so that the valve F is now raised, and a fresh
supply of gas enters the bellows. In this way the bellows
are constantly rising and falling. If but one lime-light is
in use, and the delivery of the gas is therefore regular,
the bellows will be almost stationary, for they will auto-
matically adjust the valve F, so that just enough gas, and
no more, will pass through the opening. But if two or
three lights are in use, and sometimes only one, and per-
haps immediately afterwards all three are requisitioned,
then the little bellows will have a more lively time of it.
In both cases the regulator will deliver the quantity of
gas which happens at the moment to be required.
Some time ago I contributed to The Camera, an illus-
trated article showing how ? by the use of a small gas-bag,
A, the outflow of gas from a cylinder might be regulated.
The bag was in this case made to raise a lever as it
filled, thus cutting off the gas supply from the bottle, until
the hag was partially emptied, when the action was repeated.
Shortly after the publication of this article a self-acting
valve on the same principle was introduced. This valve
THE BOOK OF THE LANTERN.
is shown at fig. 29. A is the loose nut by which it is
attached to the gas-bottle ; B, the
valve proper, which is governed
by the spring lever D. The
tendency of this spring is to keep
the bag shut, and when in that
position the tap is open. The
gas pressure, however, quickly
inflates the bag, and turns off the
gas supply. The delivery pipe,
E, is connected with the lantern.
The. apparatus is small and com-
pact, and works well.
It may be noted here, that there is a distinct gain in
using pure hydrogen, instead of the carbureted gas
from the main, although its employment undoubtedly
leads to extra trouble and ex-
pense. The most convenient
way of making this gas in small
quantities is by treating scrap
zinc with dilute acid. A con-
venient apparatus is that shown
in the diagram, fig. 30. It was
devised some years ago by Mr.
Pumphrey, and published in one
of the Photographic Annuals.
It consists of a copper container,
in which is an inverted box with
a delivery tube and tap attached
to it for drawing off the gas as
it is generated. This inner box
70 THE BOOK OF THE LANTERN.
has a removable perforated shelf fitted to it, and the box
itself is so arranged that it can be wedged tightly in its
place. The shelf is to hold the necessary supply of
scrap zinc, and as . the acidulated water attacks the
metal, hydrogen is rapidly given off, until the water is
forced by the pressure of the gas below the shelf, and
the action ceases. It is again renewed when gas is
drawn off from the tap, for then the water again rises
to the zinc, and a fresh supply is generated. This
apparatus is clearly a modification of the Dobereiner
lamp, in which the gas generated in this manner impinges
upon and renders red-hot a -pellet of spongy platinum.
At a recent lantern exhibition at the Crystal Palace, where
a 30-foot screen was used, pure hydrogen from a bottle
fed the lime-light. On one occasion ordinary coal-gas was
substituted, with a loss of light which was estimated by
those well qualified to form a judgment, at no less than
25 per cent.
THE LIME-LIGHT AND ITS MANAGEMENT.
[HE lime-light was discovered about the year 1826
by Lieut. Drummond, R.E., during the progress
of the Ordnance of Ireland Survey, when the
want of some method of signalling between distant stations
was much felt. As originally constructed, Drummond's
lamp was very different to the convenient forms of lime jet
now in use. It consisted of a blow-pipe, which impinged
upon a ball of lime about as big as a marble. This lime
ball did not last more than half an hour, but when spent
another took its place automatically. The lime ball was
placed in the focus of a parabolic silvered-copper reflector.
With this apparatus, the light was visible from Antrim in
Ireland, to Ben Lomond in Scotland, a distance of ninety-
five miles as the crow flies. Upon another occasion, the
light from the Drummond lamp was distinguishable at a
distance of one hundred and twelve miles.
When manufactured limes cannot be obtained, a piece
of limestone fresh from the kiln can be sawn roughly to
72 THE BOOK OF THE LANTERX.
the cylindrical form, and rubbsd down with a file ; or a
piece of good hard chalk will serve, if there is nothing
better at hand. The following mixture has been recom-
mended as one from which a hard substance can be
moulded which will take the place of the usual lime
Precipitated Chalk 4 parts.
Heavy Magnesia, Carbonate 1 part.
Mix to paste with gum-water, and mould to form.
Of late years some new limes have been introduced, with
the trade-mark "Excelsior." These will do admirably for
the blow -through jet, but will not (at any rate in my
hands) withstand the attack of a powerful mixed jet. I
have always regretted that I cannot use them, for they are
uniform in size, are accurately turned and bored, and are
packed in a. very convenient manner. A good hard
material which will last for several hours, and which is not
affected by damp, is a thing that is much wanted for lime-
light working. The following extract from Lieut. Drum-
mond's paper in the Philosophical Transactions, 1826, is
interesting, as showing that the discoverer of the lime-light,
made trials of various substances, but found lime to be the
" The results of several trials made at the commencement,
Lime 37 times
Zirconia 31 times
Magnesia 16 times
the intensity of an Argand burner. The oxide of zinc was
THE BOOK OF THE LANTERN. 73
also tried ; but besides wasting away rapidly, it proved
inferior even to magnesia.
" Of these substances, and also of their compounds with
one another, lime appearing to possess a decided superiority,
my subsequent experiments were confined to it alone, and
by a more perfect adjustment of the apparatus, by bringing
the maximum heat, which is confined within narrow
limits, exactly to the surface of the lime ball, and by using
smaller balls than those employed in the early experiments,
a very material increase of light has been obtained. The
mean of ten experiments, made lately with every pre-
caution, gives for the light emitted by lime, when exposed
to this intense heat, 83 times the intensity of the brightest
part of the flame of an Argand burner of the best construc-
tion, and supplied with the finest oil. The lime from chalk,
and such as is known at the London wharfs by the name of
flame lime, appears to b3 more brilliant than any that has
been tried. When well-burned Carrara marble is made
into a paste with water, and gradually dried, it appears to
be nearly equal to the preceding ; when strongly com-
pressed, or very porous, it is inferior."
The best limes to be obtained are of the kind known as
"hard," or "Nottingham limes." These last better than
any others that I know of. They are sold in tin boxes
holding one dozen each, and are packed in powdered lime,
kept as far as possible from the air. Let it be remembered
that these limes will be spoiled by exposure to damp air.
By such exposure they swell to double their normal size,
will break the strongest box in which they are confined,
and will, finally, fall to powder. In other words, they are
74 THE BOOK OF THE LANTERN.
made of quick lime, and moisture will slake them. Lime
cylinders are difficult things to keep, for damp air will get
to them in spite of ordinary precautions. I have tried to
preserve them with partial success by dipping each
cylinder separately into a solution of indiarubber in ben-
zole or chloroform, which forms a skin upon its surface.
An American writer publishes a better plan. He melts
some solid paraffin or bees' wax in a metallic vessel,
exercising care that the heat is just enough to render
the substance liquid and no more. He then dips each
cylinder into the wax half way, allows it to cool, and then
holding it by its waxed end, dips the other half. This
coating, he says, quite excludes the air, and the limes may
be rolled in paper and packed away until 'wanted for use.
The coating is readily peeled off when the lime is required
for the lantern, provided that the heat employed in melting
the wax was not too high when the cylinders were dipped.
Each lime is cylindrical, and about one inch and a half in
length, with a central hole for the reception of the pin
upon the jet. This hole should be carefully freed of
powdered lime, by running a match through it, after
which the cylinder can be placed upon its pin, where for
the present we will leave it.
As already indicated, the most commonly used form of lime
jet is the safety, or blow-through kind. If the jet be a
properly-constructed one, it will well illuminate a picture
15 feet in diameter. In this jet the hydrogen is sup-
plied from the nearest household source, by a connecting
tube of india-rubber. Herein lies, perhaps, its only dis-
advantage. In an ordinary house the connexion is an
THE BOOK OF THE LANTERN. 75
easy matter, but in large halls, which are now commonly
lighted by one or two sunlights high overhead, the
operator finds himself in a serious difficulty. In this jet
the two gases do not mix until they reach the point of
combustion, and for this reason the apparatus is dis-
tinguished by the word " safety." For hydrogen and
oxyen, when mixed together, form an explosive vapour of
most terrible power, and one which is most difficult to
control. If any one should wish to prove this, let him fill
a soda-water bottle with the gases over a pneumatic trough
in the proportions of two volumes of hydrogen to one of
oxygen. Then close the bottle with a well-greased cork,
and, after wrapping it in a towel in case of fracture, take
out the cork, and put the mouth of the bottle in front of a
candle flame. The report caused by the explosion of the
gases will be quite equal to a heavily-charged fowling-
piece. But when the two gases are used in conjunction
with the safety-jet there is no risk of explosion, for no
mixture takes place until the gases meet on the lime
cylinder. I know that accidents have happened when
this jet has been in use, but they are traceable to im-
proper use of the apparatus. A case of this kind came
under my notice quite lately. An optician had employed
a new hand to see after the making of the oxygen gas and
filling the bag with the same. This individual was, after
a time, left to his own devices, and finding, upon one
occasion, that the bag was not full, he attached it to the
nearest gas-bracket until it was properly distended. This
bag was used in public the same evening, and a few
minutes after bhe proceedings commenced it blew up, and,
76 THE BOOK OF THE LANTERN.
besides wrecking the lantern, smashed all the windows in
the hall. The cause of the disaster leaked out afterwards.
But with proper care this jet is perfectly safe, and
one which I have used scores of times for purposes of
demonstration in crowded school-rooms. As the bulk of
my readers are more likely to adopt this form of limelight
than any other, I will give directions for working with it
which will at once show its simplicity. We will suppose,
in order to make the matter clearer, that the operator has
a single lantern fitted with this form of jet.
Beyond the mere lantern and its belongings, there will
be required some india-rubber tubing, a box of limes, and
a bag or bottle of gas. The best rubber tubing is the red
variety ; but it is expensive. It will, therefore, be found
economical to adopt a plan which I myself have practised
with advantage. Two lengths of tubing are required, one
for each of the gases employed. A 6-foot length will be
sufficient to connect the side of the jet with the iron
bottle or bag ; but the length of the other piece of tubing,
which is to connect the H side of the jet with the nearest
house gas-burner, is obviously dependent upon the distance
of that supply from the place where the lantern is being
exhibited. If the nearest tap is in another room, it is best
to use a length of compo. (lead) gas-pipe, which is absurdly
cheap. Upon one occasion I remember drawing the gas
from another house by such a means of communication,
the pipe passing through two windows. But it is only
upon rare occasions that such a proceeding is necessary,
and the worker is generally able to find a source of gas-
supply ready to his hand. When such is the case, I
THE BOOK OF THE LANTERN. 77
recommend the employment of two different kinds of
tubing. There is a hard black kind, made, I fancy, in
France, but easily procurable in this country, which wears
extremely well, far better, indeed, than the ordinary grey
kind. It is cheap as well as good. The only part where
it seems to deteriorate is the end, where it is being
constantly fitted on to the metal jet. This gets soft and
rough after some time, a failing which is easily remedied
by judicious amputation. Use for each gas a sufficient
length of this black tubing, and firmly attach to the end
of each piece a short length of the more elastic red tubing,
by which connexion with the bottle and house gas respec-
tively can be easily made. In joining the two kinds of
tubing together, use a couple of inches of lead pipe as a
connecting link between them. First draw the black
tubing half way over the lead, and then, if possible, allow
the red tube to cover both, securing the whole with
string. , -
Having all these things ready, the H tube fastened to
the nearest gas supply, and the tube to the bottle or bag,
we can proceed to work. Let the lime-pin be so adjusted
that the lime is about 1-1 6th of an inch from the nozzle of
the jet. Then turn on the tap marked H, and light the
jet. Turn down the gas until the flame is about one
inch high, and let matters thus remain for five minutes, to
give the lime time to warm through. Without this pre-
caution, and if the oxygen is turned on at once, the lime
is apt to split up from the sudden heat.
After this five minutes' rest, you may attend to the
oxygen supply. If the gas is supplied from a bottle or
78 THE BOOK OF THE LANTERN'.
cylinder first turn the tap of the jet full on, and let it
remain so. This is a most important point, and for the
following reason : the supply of oxygen must be regulated
only from the tap on the bottle, for the pressure of gas is
so great that if we turn on the bottle tap and then attempt
to check its flow by moving the tap jet, the connecting
rubber tube will be blown off or possibly split up. There
is another advantage in keeping the hydrogen jet burning
for some time before the lantern is used. It warms the
glasses, and prevents that deposit of moisture upon them
which is otherwise always more or less apparent, especially
in a crowded room. Turn the H tap until there is a good
big flame from the jet, and now very, very gradually turn
the lever tap of the bottle. If you do this too quickly, the
sudden mixture of and H at the jet causes the light
to go out with an unpleasant crack. There is really no
danger, but the noise frightens nervous people, who are
prone to associate with lanterns generally the idea of being
blown skyward. The regulation of the two gases is a
matter which is soon learned by experience, and is governed
by the appearance of the disc of light obtained on the sheet.
Move the two taps until the best effect is obtained ; the
knack of doing so is very soon learned.
Having seen that the gas jet is burning well and quietly,
which is one sign that all is at it should be, the next thing
is to see that the light is perfectly central with the optical
system. See that the tray upon which the jet is fixed is
withdrawn so as to leave a space of about 4 inches
between the light and the condensing lens. Raise or lower
the jet on its supporting rod, and move it from left to
right until the flare of light seen upon the sheet is as
THE BOOK OF THE LANTERN. 79
central as possible. When this is the case, tighten the screw
or screws (and two are better than one) which hold the jet
on the rod, so as to clamp it firmly in position. Now press
forward the tray, so that the light approaches the condenser,
and this will cause the sheet to become equally illuminated
with a sharply -defined margin all round. Now place a
slide on the stage of the lantern, and focus it as sharply as
possible. The best way to do this is to set the focussing-
screw so that it is at its middle position, then focus by
sliding in and out the flange into which the objective is
screwed. Get roughly the best focus which you can obtain
by this means, and then give a finishing touch by means of
If a double or biunial lantern be employed, the necessary
operations will be rather more complicated, for here we shall
have two lights, and two optical systems to control instead
of one. But, when once understood, the working of a double
lantern is both simple and easy, so much so that on many
occasions when a good assistant was not forthcoming I have
worked the lantern myself and lectured at the same time.
The two lanterns are connected by means of a dissolving tap,
such as that shown in fig. 3, which is a very good pattern.
This tap is so arranged that when the lever is upright both
lanterns have their full supply of the gases ; when the
lever is turned over towards the left-hand side, the lower
lantern only is provided for, whilst when in the reverse
direction the upper one is supplied with gas. The original
plan for dissolving was to move a couple of serrated
screens to and fro in front of the lenses, both jets
continuing burning during the entire exhibition. The
more modern method of cutting off the gas supply from
80 THE BOOK OF THE LANTERN.
each lantern alternately has the great merit of saving
nearly half the gas bill. It will be noticed in the cut of
the dissolving tap that it is furnished with two small stop
cocks, which are fixed on vertical tubes near its centre.
These tubes are by-passes which allow a small quantity
of gas to pass to each burner, although the lever has
shut off the main supply. The necessity for this arrange-
ment is obvious ; without it the lantern not in actual use
would be totally extinguished. In using the blow -through
form of jet :both by-passes, must be employed, but with
the ;mixed jet the hydrogen by-pass only is necessary.
The first thing to be done in operating with a double
lantern is to light the hydrogen in both lanterns, and to so
adjust the by-pass that it will admit just enough gas to
the lantern not in use to give a flame about half an inch
high. When the blow -through jet is used the correspond-
ing oxygen tap must be manipulated to furnish just enough
of that gas to tinge the hydrogen flame. If this precaution
THE BOOK OF THE LANTERX. 81
be not taken, the sudden influx of oxygen to the burner,
when the dissolving lever is turned, will almost infallibly
cause the flame to snap out with a sharp crack.
The mixed jet is as easily worked as the safety form and
despite the confidence-inspiring name of the latter is,
in my opinion, quite as safe in careful hands. In some
forms of mixed jets pumice-stone chambers, receptacles
charged with discs of wire-gauze, and other arrangements
which are supposed to prevent the flame passing back
through the tubes, form part of the design. I look upon
such contrivances as mere obstacles to the free passage of
the gas \ and, although some of my jets were originally
provided with them, I did away with them as quickly as
The dissolver for a triple lantern is naturally more com-
plicated ; but taps have been devised which are so arranged
that any one of the three lanterns can be put in or out of
action at will. Such a tap is shown at fig. 33. Another
82 THE BOOK OF THE LANTERN.
pattern of very compact form is illustrated at fig. 34. In
this case the by-passes are governed by taps which are
adjusted by the operator with a screw-driver. This seems
to be a good arrangement, as there is no chance of
accidental turning off or on by a careless touch, as may
happen when the by-pass taps are exposed.
There are one or two methods of manufacturing oxygen
gas for the limelight as fast as it is used, and although,
for reasons which I shall presently give, I cannot recom-
mend such a procedure, the methods are ingenious enough
to warrant notice. In Chadwick's apparatus there is an
iron gas-holder, which forms the support of the lantern.
Associated with it is a special form of retort heated by a
Bunsen burner, and charged with chlorate of potash and
manganese made up into a cake previously. The operator
starts with a full gas-holder, and at the end of perhaps
fifteen minutes, when it is nearly empty, lights the Bun-
sen burner, and in a few minutes enough gas is generated
to fill it once more. The retort is now charged with a
fresh cake of mixture ready for once more filling the gas-
holder as it sinks.
THE BOOK OF THE LANTERN. 83
Another plan was originated some time ago by Mr,
Beseler, of New York, and published by him in one of the
American journals. In this case the mixed chemicals are
placed in a metal tube, with a Bunsen burner beneath it.
As the gas is generated it fills a small gasholder, which
supplies the lantern. Only one part of the tube at a time
is subjected to heat, so that when a fresh supply of oxygen
is wanted, all that is necessary is to shift the Bunsen
burner to another part of the tube, and the gasholder is
replenished. This latter plan is more simple than Chad-
wick's ; but I object to both, unless it be for experimental
work at home, on two broad grounds. One is, that the
blow-through jet can only be used in conjunction with
such an apparatus, and the other is, that a lantern operator
has quite enough to do in attending to his burners and
changing the pictures without being burdened with the
constant anxiety of seeing to the gas supply.
Of late years much has been heard about the so-called
ether-oxygen or ethoxo limelight, so called because the
vapour of sulphuric ether is used in lieu of the ordinary
hydrogen, or coal-gas. I have tried this light, and, while
admiring its brilliance, which is quite equal to any form
of limelight which I have seen, I am very doubtful as to
its safety. I have no doubt that it can be so arranged as
to work with safety ; but several explosions which have
occurred with it show very conclusively and unpleasantly
that that time has not yet arrived. With the tempting
advantages of extreme portability and brilliant light
which this or any other system may offer, I hold that it is
a positive duty to eschew it until it is known by further
84 THE BOOK OF THE LANTERN.
experience to be absolutely innocuous. Some may say,
" Oh, there is no real danger ; the worst that can happen
is one of the tubes blowing off with a bang ! " But this
apparently harmless "bang" may cause a panic in a
public hall, which may lead, possibly, to fatal results. So,
for the present, at any rate, I shall do without the ether
light, while, at the same time I shall look forward to its
gradual perfection with the greatest interest. It is only
fair to state that this light is much used in America,
its greatest champion being Mr. Ives, who recently con-
tributed a paper on the subject to the Franklin Institute.
Mr. Ives is such a good worker that his words carry weight
with them. I quote the following remarks from his
" Notwithstanding the great success of this means for
producing the limelight, and the important advantages
which it offers, I have always recognised in it certain
minor faults, which I hoped to overcome in course of time,
and my object in preparing this paper has been to call
attention to some recent improvements I have made, which
I believe will greatly extend the use of the light, and
increase its popularity. The first improvement is in the
construction of the saturator, which is reduced in size, yet
increased in effectiveness. The second is in the use of
petroleum ether (rhigolene), which gives the same light as
sulphuric ether, but vaporises at a lower temperature, costs
much less, and contains neither alcohol nor water to accu-
mulate in the saturator.
"My improved saturator is in the form of a single
metallic tube, 2 inches in diameter and 13 inches long,
THE BOOK OF THE LANTERN. 85
with a handle at the middle and a stop-cock projecting up-
ward at each end. A neck, like that of a bottle, projects
from the screw cap at the end, and is closed with a cork
for convenience in filling. The passage for oxygen is over
20 inches long, in the form of a zig-zag channel through
the upper surface of the roll of porous material, and
secures complete saturation of the gas with vapour. The
saturator can be filled from a bottle in one minute, and is
ready for use at once, or may be kept filled for any length
of time. Petroleum ether costs only thirty cents a pound,
which is less than half the price of sulphuric ether ; it also
vaporises at a lower temperature, so that the light can be
used successfully even in a very cold room, and it has
other advantages. It will supply a pair of lanterns con-
nected by dissolving key, for two hours continuously. It
should be stored in a cool place and kept tightly corked.
It is also necessary, when using it with oxygen from a
cylinder, to use a valve that can be opened very slowly,
because a very small amount of oxygen passing the satu-
rator will produce a very large flame at the jet. The
Shaw valve, manufactured by Mr. Shaw, a member of this
Institute, fulfils the requirements, and is already largely
used in this city. Some special instruction for the manage-
ment of the light in hot weather may also be called for.
" In conclusion, I give it as my opinion that this im-
proved means for supplying the hydrogen element is so
much simpler and more convenient than any other, that it
cannot fail to entirely supersede the use of hydrogen and
coal-gas, when its merits shall have become generally
known and appreciated."
this head comes the sheet, hung in
the required position by supporting cords, and
screens fixed on built-up frames.
First, as to the simple sheet. A badly-hung sheet is
an abomination. It should be so hung that there is a cer-
tain pall upon it from the centre to the edges all round,
and this may b3 brought about by following the directions
now given. The sheet may be made of either linen
or cotton. I prefer the latter, because it is cheaper, and
more opaque, and we shall presently see that opacity car-
ries with it certain advantages. . If the sheet is of such a
size that it must be joined (that is to say, if it be more
than about 10 feet square), the necessary seams should lie
horizontally, not vertically. A sheet in which the seams
are vertical, is liable to hang in festoon-like folds ; but if the
seams be horizontal, it will hang straight, so long as its top
edge is properly secured. The sheet should have along
this edge a broad hem, in which is run a strong cord-
This cord should be firmly fastened to the corners of the
THE BOOK OF THE LANTERN. 87
sheet, and in such a way that when it is stretched, the
material of which the sheet is made will not pucker. At each
end of this cord there should be a loop made by doubling
it over, and wrapping it round with waxed thread.
Along each side of the sheet should be placed, at intervals
of about eighteen inches, galvanized iron rings, or brass
curtain rings will answer the purpose. The bottom of the
sheet may be left free.
A screen of this description will require no fittings to
hang it in position, beyond a couple of screw-eyes placed
so far apart that the sheet will easily go between them ;
and which should be inserted in the cornice or roof of the
exhibition-room, with two more eyes placed immediately
underneath the top ones, and screwed into the floor. Next
are required two strong but thin cords ; and it is best at
the outset to procure these of the best quality possible, for
upon their strength the sheet entirely depends. Eich cord
should be fitted at one end with a swivel and clip like that
upon a dog's chain.
Having made these preparations the hanging of 'even a
large sheet will be comparatively easy. First, let the cords
be run through the fixed screw-eyes in the roof or upper
pirt of the wall ; one cord through each eye, and so inserted
that the clips on the cords are inside, i.e., facing each
other. Next clip the sheet to the cords by the loops pro-
vided at the top corners, as already described. The sheet
can now be pulled up bodily, preferably by two persons,
one at each cord. Next place the free ends of the cords
through the screw-eyes in the floor, and stretching the sheet
as tightly as possible, secure each by a simple knot.
THE BOOK OP THE LA.NTERN.
We shall now see the advantage of the eyelet-holes or
rings at the sides of the sheet. Fastening a piece of
string to the top eyelet-hole at one side, and this is better
done before the sheet is pulled into position, allow that
string to embrace the supporting cord, next let it pass
through the nearest eyelet-hole, then again round the cord,
and so on until the bottom of the sheet is reached. By this
lacing method the sheet can be rendered almost as flat as a
board, and presents the best possible kind of surface so far
as a sheet can give it for showing lantern pictures well.
Some little judgment must be exercised as to the best
position for the upper screw-eyes. Of course, in practice,
difficulties are apt to occur. The best position may be one
which the ladder available will not reach. Again, it is
often the case that screw-eyes may be found already
in position, and the owners of public halls have a righteous
Fig. 35. A B
objection to holes being made, even to the tiny ones
necessary for fresh screw-eyes. In such a case the
THE BOOK OF THE LANTERN.
exhibitor must content himself with existing arrangements.
But supposing that he has a free will in the matter, he
must exercise his judgment with regard to the size of the
hall, and the best position for hanging a sheet. For in-
stance, in a hall with a pointed roof, the position A (see
figure 35) would be preferable to position B. In some
halls, again, the walls may be so far apart that the sheet
will, when hung in the manner described, drop consider-
ably by its own weight, so that, although the screw-eyes
may be 20 feet from the ground, the top edge of the sheet
will be only 14 or 15 feet above the floor. The best
way of obviating this is by the use of two wooden struts,
or supports, placed as shown in figure 36. In this dia-
gram the dotted lines indicate the position which the sheet
would occupy without this help.
The material of which the screen or sheet is made is of
far more importance than would be thought by an inexperi-
enced worker. A careful artist knows that a good picture
cannot be produced on crumpled or dirty paper ; and the
lantern exhibitor should be quite as careful to provide for
his pictures an unblemished and even surface. Un-
00 THE BOOK OF THE LANTERN.
doubtedly the best thing of all is a simple white-washed
wall. Why should this be so ? Let me endeavour to
explain the matter in a few words.
Suppose that we go behind an ordinary linen or cotton
sheet, while lantern pictures are being thrown in front and
upon it. We not only see the picture distinctly through
the sheet, but there is enough light round about us to enable
small print to be read with ease. At least such is the case
with the lime-light, and in a minor degree with the oil
lantern. Now all this light means so much deducted from
the light available from the lantern, and which, therefore,
is completely lost to the spectators in front. From an
opaque wall, on the other hand, the light is nearly all reflected
to the spectators' eyes ; and although no doubt some must
be absorbed, we know that none is actually transmitted
through the screen, and utterly wasted, as in the case of a
semi-opaque sheet. We might compare the two cases, to a
vessel of water with a porous bottom, which will, of course,
allow a large portion of the liquid to dribble through and
be lost ; as against a vessel with a solid bottom which will
hold water without any wasteful transmission. But a
white-washed wall is not often met with in a lecture-hall,
and the best substitute is a canvas sheet rendered opaque
with white-wash. Such a sheet is portable up to a certain
size ; and if intended for use as a fixture in any one hall,
can be made up to any size, within reasonable limits.
Witness the scenes on rollers at our large theatres and opera
houses, the basis of which is simply whitened canvas. Such
a plan was adopted at the late Polytechnic Institution, where
the screen measured no less than 26 feet across.
THE BOOK OF THE LANTERN. 91
There is a further advantage connected with using a
sheet of this description, which is that when, not in actual
use it can be rolled up, and will keep perfectly clean for
many years. When soiled, a fresh coat of white-wash can
be given to it with little trouble and expense. For home
use a screen of this nature is to be greatly recommended.
Let me now describe the method by which such a surface
can be prepared, and the best way of hanging it in position.
The following detailed directions are quoted from an article
upon the subject which I wrote some time back :
Having decided upon the dimensions of the screen,
which, of course, must be governed by the size of the
room in which it is to be hung, we must first of all have a
frame made upon which the material can be stretched
whilst being painted. Any kind of close-textured material
will answer our purpose, good unbleached calico being as
suitable as anything else. The frame should be strong,
for as soon as the sheet is wetted it shrinks, and is apt to
pull an ill-constructed frame all askew. The calico, if
joined, should be neatly sewn, and so tacked on the frame
that the seam, or seams will lie horizontally. The sheet
must be nailed on the frame with tacks, and this appa-
rently simple work must be done in a certain way, or
it will be pulled into creases. The four corners must
be first secured, and afterwards the sides may be nailed
down, one side being completely nailed before another is
begun. By this means the sheet will, when done, present
one even surface. This done, it must receive a coat-
ing of size. The best double size should be used, and
should be melted in a suitable vessel with its own weight
92 THE BOOK OF THE LANTERN.
of water. The size while on the fire should be watched
and occasionally stirred, but should not be allowed to boil.
When melted, this size is well brushed into the calico, and
allowed to dry. It will then be ready to receive its
coating of white paint. This consists of whiting which
has been soaked in water until it assumes the appearance
of thick white mud. To this strong melted size must be
added until the mixture is of the consistence of cream.
It can be left now for some hours until it has become
perfectly cold. At the end of that time it should have
the appearance of very weak jelly, a jelly which can be
easily broken up by the paint brush.
The frame being placed upright and properly secured,
the workman commences at the top, working the well-
charged brush up and down, and then horizontally, so as
to avoid leaving any lines upon the surface, until it is all
covered. If the sheet be unusually rough in texture, it
will benefit by another cqat when the first is dry.
When this painting operation is finished the nails must
be drawn from the frame, and the sheet must be tacked
on to a roller. This roller may be hung like a window-
blind at the top of the room, and governed by a cord in
the familiar manner. But if it is of large size, say 12
feet across or more, the roller is best placed at the bottom
of the sheet, and made to roll up by cords upon its pro-
jecting ends, and pulleys above like the drop scene at a
It has often struck me as a deplorable oversight that
halls where lantern lectures are of constant occurrence,
are not fitted with permanent roll-up screens of this kind.
THE BOOK OF THE LANTERN. 93
T know most of the lecture-halls in the kingdom, but I am
not aware of a single one where this arrangement exists.
The lecturer who visits these places is responsible for
bringing his own screen, and his assistant must fit it up,
an operation which is sometimes, owing to the structure
of the hall, very troublesome and difficult. A permanent
rolled-up screen would obviate all this difficulty, and would
add greatly, for the reasons already given, to the success of
the exhibition. I can only suppose that this is one of those
matters which comes under the head of everybody's
business, and therefore nobody attends to it, or seeks to
remedy what I feel is a mistake.
We will next consider the method of hanging a sheet on
a portable frame. Some lecturers adopt this plan, and if
they are not afraid of adding to their luggage a huge
bundle of sticks, they certainly have the advantage of
being independent of ladders, staples, and all the things
necessary for hanging a sheet in the ordinary way. There
are several descriptions of frames made for this purpose,
which are sold by dealers ; some are good, and some
are very much the reverse, giving much more trouble
than they are worth. Perhaps the best form of frame is
that which is made of round pine sticks, about 4 or 5 feet
long, like broom-sticks, and which fit to one another,
fishing-rod fashion, by means of brass sockets. The
corners of the frame are represented by sockets mitred, and
brazed together, see fig. 37. Such a frame as this is easily
put up. First of all the top pieces are socketed together,
and furnished with their corner pieces and one length of
the wooden rods. The side pieces are next placed in their
THE BOOK OF THE LANTERN.
proper sockets, and the top portion of the sheet is tied on by
tapes. It is reared up a little higher by the addition of two
more side pieces ; and as this building-up gradually goes on
the sides of the sheet are secured by tapes to the frame. The
bottom pieces are finally attached a.nd the frame is com-
plete. If there is room enough this operation of mounting
the sheet on its frame is best performed when both are
lying flat on the floor, otherwise it must be done by
gradually building up the frame while it is in a vertical
position. At each top corner should be fastened guy
ropes, and these can be secured to staples screwed into
One advantage of a frame of the above description is
that, when, from the nature o'f the hall, it must be erected
on a platform at a higher level than that of the lantern,
the whole screen can be made to incline forwards, so as
to bring its surface square with the lens. With a strictly
vertical sheet the picture would, under such circumstances,
be thrown out of shape and out of focus.
Whatever wood may be chosen for the material of the
THE BOOK OF THE LANTERN. 95
frame, it should be strong ; for if the sheet is tightly-
stretched, as it ought to be, there will be a very heavy
strain upon its support. Perhaps the best wood for the
purpose is bamboo, which combines the qualities of
extreme lightness with great strength. I believe that
bamboo frames can now be obtained commercially.
The rule for finding the correct distance between lantern
and sheet is to add one to the number of times enlargement
required, and multiply by the equivalent focus of the lens
used. If, for instance, a slide measures 3 inches, and it is
desired to cover a screen 10 feet across, the scale of
enlargement is 40 times : and 41 times the equivalent
focus of the lens gives the required distance between lens
In order to find the equivalent focus of a lens, it is con-
venient, in the absence of special apparatus, to proceed as
follows : Focus upon a white surface an image of the
Sun or other distant object, taking care to place the lens
axis as nearly as possible in line with the object, and
perpendicular to the surface receiving the image. When
the image is sharply focussed, measure carefully the dis-
tance between it and the nearest surface of the lens.
Repeat this operation with the lens reversed, and measure
the distance to the same surface as before ; in this case,
the surface furthest away. The average of the two
measurements thus obtained is approximately the
equivalent focus of the lens.
I am indebted to Mr, Taylor, of Leicester, for the fol-
lowing useful table :
THE BOOK OF THE LANTERN.
TABLE OF DISTANCES BETWEEN LENS AND SCREEN FOR
VARIOUS SCALES OF ENLARGEMENT, AND WITH LENSES OF
VARIOUS EQUIVALENT FOCAL LENGTH,
THE PEEPAEATION OF LANTERN SLIDES, DIAGRAMS, ETC.,
WITHOUT THE AID OF PHOTOGRAPHY.
it became possible to use photography in
conjunction with the lantern, what are called
hand-painted slides had to be depended upon,
for they were the sole pictures that could be obtained.
In those days it was common to use a very much
larger picture for the lantern than at present. Those
pictures which delighted one or two generations of sight-
seers at the old Polytechnic, measured about eight inches
by five. Some of these pictures were most elaborate works
of art ; so much so, that at the sale of the belongings of
the Polytechnic in 1881, when the Institution as a place of
entertainment was broken up, many of these slides real-
ised as much as fifty shillings each. It is to be feared that
such hand-painting on glass is now almost a lost art, for
people will not pay the price which would remunerate a
competent artist, when they can obtain a more perfect
representation, as to form at least, by means of a photo-
graph. The slide-painter of those days used to work both
98 THE BOOK OF THE LANTERN.
in water colour and in oil colour, sometimes, I believe,
combining the two methods in one picture ; and his first
proceeding was to draw the outline on the glass, in black
pigment, with a very fine brush. Those who do not wish
to dabble in photography, and who have some artistic taste
may still adopt the same plan, and they will find that with
a little practice they will be able to draw with a fine brush
and with a suitable pigment, as finely as they can on paper
with a pen. The Japanese artists, I may mention, do all
their work, and even their writing, with a brush, and we
all know their pictures are not to be despised. It will
be found that such an outline is easier to produce if the
glass be first covered with a layer of varnish. Some use
a weak solution of gelatine in water, to give the glass the
necessary surface for taking the pigment. A solution of
sugar has also been recommended for the same purpose.
A still easier plan of producing diagrams of line drawings
without the aid of photography is to use sheet gelatine,
which is sold for the purpose. This gelatine is placed over
the engraving or other design which it is wished to copy ;
and the lines are traced with a sharp point, such as an
etching-needle. Fine black lead is then rubbed over the
surface with the top of the .finger, with the result that the
black powder lodges in the scratches, but does not adhere
to the smooth surface. This plan I look upon merely as a
makeshift; but I mention it for what it is worth.
A method by which far better results can be obtained
was published some years ago by the Rev. Dr. Dallinger,
the eminent microscopist, who has for a long time used
slides produced in the way he describes. His plan is
THE BOOK OF THE LANTERN. 99
briefly this. He works with a hard pencil on a piece of
very finely-ground glass ; afterwards filling in the outlines
thus made with water colours, and applying a coat of var-
nish so as to give the necessary transparency to the picture.
This method he brought before the Royal Microscopical
Society, and the following extract from his paper describes
the matter so clearly that all will be able to follow his
" Most working microscopists have felt the necessity, in
reading papers on their work, of accurate illustration.
These enlarged drawings fail in matter of detail, unless
extravagant labour is expended, and considerable skill
employed. Even then the light of an ordinary lecture
hall is not enough to enable the most distant of the
audience to see them. It is only by means of the limelight
and transparencies that really useful illustrations can be
given. But here the difficulty is to prepare them accu-
rately and inexpensively. Photography cannot be employed
in all cases ; and even where it can be, it involves more
labour than most microscopists can afford. Drawing and
painting on glass in the usual method is an art that it takes
years to learn ; and to employ one who has learned it to
draw from nature a highly-magnified object, would be to
introduce unnumbered errors of interpretation, unless our
artist be a microscopist himself.
" I obviate all these difficulties by the following method :
On finely-ground glass, drawing with a black lead pencil
is as easy as drawing on London board. I get four inch
squares of glass to suit my lantern, carefully ground on
one side like the focussing glass of a camera. Now with
100 THE BOOK OF THE LANTERN.
the ground side up, the camera lucida may be used with
this as well as with drawing-board, if a piece of white
paper be placed beneath it, and the object drawn in the
usual way. For outlining and delicate shading I employ
H H H H and H H H pencils ; for deep shadows I use
H B. By a very delicate employment of the pencil,
shadows softer than can be secured by lithography may be
made. The camera lucida, of course, is not necessary ; we
may draw with the eye and hand alone. If it be necessary
to put on colour it may be done cleanly and carefully over
the shading ; thus one layer of colour suffices. Now of
course, although we have a perfect drawing of the object,
with all the detail accurately given, it is not a transparency.
But we can easily make it one. Thin some good pale Canada
balsam with benzine to about the consistence of cream ;
and simply float it over the ground surface of your glass,
pour off till the drop comes very sluggishly. Then reverse
the glass so that the corner from which the balsam was
flowing off be placed upward. Let the return flow reach
about the middle, then reverse it again, and move it in
several directions to get the balsam level. This may be
done with very little practice so that the surface shall be
undistinguishable from glass. We have now a perfect
transparency. All that is required is twenty -four hours
for hardening (keeping the glass level) and then another
square of glass fastened on to it by strips of paper at the
edges, with small pieces of card at the corners to prevent
contact, and it makes an admirable lantern transparency.
"For obtaining very fine points to my very hard leads, after
cutting them very long and even ? and grinding them on
THE BOOK OF THE LANTERN. 101
glass paper, I finish them on a square of the finest ground
glass, and with this beside one in making a delicate
drawing, a -good, fine working point may be Ue*p*t' 8 loag
while." ' t,
There is sometimes a difficulty in procuring ground-glass'
fine enough for this purpose, and I therefore advise those
who feel inclined to try this method of producing lantern-
slides to prepare the glass themselves ; which is somewhat
tedious, but by no means difficult. Or should they prefer
it, they can purchase the glass at certain photographic
warehouses, where it is sold for focussing purposes in the
camera ; but it is rather expensive. The following direc-
tions will enable any one to grind the glass for himself :
First of all, obtain a piece of glass which is both flat and
perfectly free from bubbles and other flaws. Be careful,
too, to cut it to the correct size at this stage of the proceed-
ings, so as to avoid all risk of mistake in this direction
after it has been ground. The glass is now fixed on a
table or board by means of four pieces of wood, nailed on
the board or table so as to clip its four sides. These
wooden pieces must not be thicker than the glass itself.
Now procure a piece of plate-glass measuring about three
inches square, to act as a grinder. Failing this, a piece of
ordinary sheet-glass can be employed ; but, as it will not be
thick enough to afford a proper hold for the fingers, it
should have attached to it a pneumatic india-rubber plate-
holder to serve as a handle.
Now take some flour emery and mix it into a thin cream
with water. Put some of this on the glass, which you have
fixed to the table, and place the grinder above it ; rub the
102 THE BOOK OF THE LANTERN.
latter over the former with a steady circular motion, taking
care to coyer every part in turn. This rubbing should
be <co*itjjnud for about ten minutes, adding water if the
two, surfaces aeem inclined to stick together too much, and
occasionally -collecting with a knife-blade the mud which
oozes out between them, and putting it once more in the
centre of the under glass. At the end of the time
named* the glass can be lifted from the table, held under
the tap for a few seconds so as to clean it, and care-
fully examined by transmitted light. It will most probably
show a fine grain, except in certain parts, which remain
clear as before. These clear portions are depressions in
the surface of the glass, which the emery has failed to
reach. The grinding operation must be repeated as before
until on examination these clear places have disappeared.
It has occurred to me that Dr. Dallinger's system of
producing lantern-slides might be modified with advantage
in the following manner. Coat the glass with varnish
which dries with a mat surface, and practically gives the
same effect as ground-glass itself. There are several
recipes for such varnish, which is used by photographers for
retouching purposes. Here is one which will be found
Ground- Glass Varnish.
Sandarac ... ... ... 90 grains.
Ether - ... 2 oz.
The proportion of benzole added determines the nature of
the mat obtained.
THE BOOK OF THE LANTERN. 103
The varnish is simply flowed over the glass and allowed
to dry cold, which it will do in a very few minutes.
After it is thoroughly hardened it can be drawn upon
with a pencil in the way described, and can then be
coloured with water colours tempered with ox-gall, as
pointed out. We can now make the picture transparent by
the addition of another varnish, which must be of such a
composition that it will not dissolve or in any way act upon
the surface already laid upon the glass. Such a varnish
would be represented by one not containing benzine as a
solvent for its gums. I have not tried this method myself,
and so cannot speak from experience ; but I do not see any
reason why it should not succeed.
PHOTOGRAPHIC LANTERN PICTURES BY THE WET PROCESS.
slides made by the wet process are
certainly easier to produce than those made by
any dry method. It is a matter of opinion
whether these are better in quality than their rivals on
gelatine, &c., and I know that many believe that a far
better effect is producible upon a wet plate than upon a
dry plate. I myself am of the contrary opinion ; but still,
as there may be many who may be inclined to try the old
collodion method, my work would be incomplete if I did
not give directions by which such slides can be produced.
If the negatives are of the same size as the lantern
plate ; that is to say, if they consist of quarter plate nega-
tives, they must be reproduced by contact ; and actual
contact with a wet collodion film is of coarse out of the
There is a method by which this difficulty can be ob-
viated. Attach to the negative a couple of strips of note
paper, 3 ~ inches apart ; the collodion film can then rest
against these paper supports by two of its edges during
THE BOOK OF THE LANTEKN. 105
the necessary exposure ; but in this case care must be
taken that the plate is thoroughly well drained, for a drop
of the silver bath solution, if allowed to get into actual
contact with the negative, will inevitably spoil it.
But those who advocate the wet process for lantern-
slide work nearly always work from larger negatives
with the camera, and by following the directions now
given it will be found that very good results can be
Place the negative to be copied in a suitable frame
against the window. This can be done by fixing an ordi-
nary printing frame (with the spring removed) against
the glass, and by covering up the rest of the window-
panes with brown paper, or some other opaque material.
Then support the camera on a stand or table, exactly op-
posite the negative, taking care that it is square with the
negative and carefully focus the image on the ground glass.
A focussing glass is a very great help in this work, for the
image is often so dimly illuminated that it is difficult to
ascertain whether it is sufficiently sharp or not. With
regard to exposure, it is very difficult, in fact impossible, to
lay down any hard-and-fast line. I can only say that
with a negative of normal density and with a favourable
light, the exposure should be about one minute ; but it is
of course governed by the type of lens used, and the par-
ticular stop employed with that lens. With a portable
symmetrical of 5 -inch focus and using No. 4 stop, the
exposure with a normal negative will be about that which
I have indicated.
But the great thing which ensures success in this process
106 THE BOOK OF THE LANTERN.
is to use a proper developer and a bath which is in the
right condition. This bath should be an old one ; that is
to say, not a newly mixed one, one, in fact, which would
give very hard results for ordinary portraiture.
It should have a small quantity of nitrate of baryta
mixed in it, say 3 grains to the ounce of bath.
Develop with sulphate of iron sat. sol. ... 4 oz.
Methylated spirit 4 oz.
Add these to a Winchester quart of distilled or rain
water ; and allow it to stand in the light for some hours,
next filter it into a clean bottle, and add 4 drops of
Just before using this developer add to it one drop of
acetic acid per ounce. This addition ensures a very fine
deposit, without it the deposit may be granular. The
exposure should be so regulated that no subsequent intensi-
fication is required, but if an error of judgment should be
made the image can be strengthened by adding a drop of
the silver bath to a little of the developer and flowing
it over the plate. The glass used should be the
best, and quite free from flaws of any kind. " Flatted
Crown " answers this description. It should be care-
fully cleaned and albumenised. The albumen should
be flowed over one side of the glass only, and it should
consist of the white of one egg to a pint of water, with
the addition of one drop of carbolic acid.
A quantity of broken glass should be placed in this
bottle and the whole shaken up into froth, left to settle and
then filtered through cotton wool. As the plates are coated
with this albumen mixture, they should be reared up to
THE BOOK OF THE LANTERN. 107
drain, and dry spontaneously on a slip of blotting paper.
The best collodion to use is " Mawson's Negative Col-
lodion." The plates should be fixed in hypo of the usual
strength, and should the image appear to be " dirty " it
can be rendered clear by being washed over with a solution
of iodine and iodide of potassium.
After fixation and after the plates have been thoroughly
washed, they may be toned in a solution of chloride of
platinum, one grain to 4 ounces of water, and they
should remain in this solution until the deposit is darkened
Beginners very often fail in getting a good tone from
platinum, and complain that instead of darkening the
image the salt has the opposite effect. They are recom-
mended in some formulae to add nitric acid to the toning
bath, but this is useless unless the platinum salt be
neutralised in the first instance. The proper mode of
procedure is to break the tube containing the platinum
crystals (this chemical, like chloride of gold, is on account
of its deliquescent property always sold in an hermetically
sealed glass tube) into a certain quantity of distilled water.
A convenient plan is to break a tube containing 1 5 grains
into 15 drachms of distilled water : one drachm of the
liquid will then represent one grain of platinum chloride.
Test this liquid before use with litmus paper: if it show by
the paper turning red that it is acid, we may be quite sure
that it contains free hydrochloric acid, which will have a
bleaching effect upon the photographic image. The liquid
must therefore be neutralised by the addition of a few
grains of carbonate of soda, after which it must be
108 THE BOOK OF THE LANTERN.
rendered sufficiently acid with nitric acid to slightly redden
litmus paper. If the operator is careful to follow these
directions he will have no difficulty in toning his trans-
parencies with platinum.
We may summarise the order of operations as follows :
Albumenise the glass.
Coat with collodion.
Sensitise in silver bath.
Fix in hypo.
Clean with iodide solution if necessary.
Tone with platinum.
The operations conclude with giving the film a coat of
transparent varnish. Any good varnish may be used, but
care must be taken if the slides are to be subsequently
coloured, that some varnish upon which turpentine has no
action be employed; otherwise the turpentine used in
colouring will most surely mingle with the varnish and
ruin the picture.
It is hardly necessary to add that the operations of sen-
sitising, developing, and fixing the plate must be conducted
in a non-actinic (red) light, and that all precautions usually
taken in dealing with photographic chemicals must be
observed. The directions are written for those who have
already mastered the details of such work.
LANTERN SLIDES ON DRY PLATES.
HERE are many dry collodion methods which,
were originally designed for ordinary nega-
tive work in the camera, but which have
long ago been superseded by the far quicker and
more certain gelatine process. Some of these plates,
however, although they have been discarded for the
main purpose of photography, are still used by many
workers for the manufacture of lantern-plates where great
speed is a matter of secondary importance.
For many of these processes the silver bath is still
required, the plate after being sensitised therein, being
flowed over with some preservative solution, the function
of which is to keep the pores of the collodion film in such
a condition that it will not dry into a horny state, im-
permeable to any developer which may later on be
applied to it. As full particulars of these processes can
be found in most photographic text-books, I shall content
myself with giving here only a brief survey of them,
reserving details of working for the more modern methods
of producing lantern-slides on gelatine plates.
110 THE BOOK OF THE LANTERN.
Many of these old processes differ only in the kind of
preservative fluid applied to them, and from the nature
of this preservative they usually are named. Thus we
have the Tannin process, the Honey process, the Coffee
process, &o. Taking the first named, let me cite it as an
example of the others.
The glass-plate which is to bear the picture is first of all
carefully cleaned. It is then edged with india-rubber
solution, albumen, or some other body which will prevent
the film from slipping off the glass during subsequent
operations. Next it is coated with ordinary negative
collodion, to which two grains per ounce of bromide of
cadmium may be advantageously added. It should now
be dipped in a silver bath which has been made distinctly
acid, by the addition of a few drops of nitric acid. After
thus sensitising the plate, it must be well washed to remove
all free silver, after which the preservative is applied,
Tannin ... ... 35 grains.
Distilled water ... 4 ounces.
After the plates are dry they are ready for use, but will
only remain good for a week or two.
In another process which gives good results coffee is used
as the preservative. In this case the bath can be made
very acid, by the addition of one-fifth of its volume of
glacial acetic acid. The plate is edged, and sensitised in
the bath, and is then flowed over with an infusion of
ground coffee. After drying, these plates will keep for
some months, and will give fine results. The development
is brought about by a plain solution of pyrogallic acid,
THE BOOK OF THE LANTERN. Ill
say two grains to the ounce of water, and is afterwards
strengthened by citric acid and silver.
A far greater importance is attached to the next method
under disscussion, by which the very finest results can be
obtained ; but it requires, at every stage of the process,
such great care that few in these days care to take it up.
Still it has a commercial importance, and is known as the
Albumen process. Here is a sketch of the operations in-
volved in it.
After the plate of glass has been rendered chemically
clean it is coated with a film of albumen from fresh eggs,
to which has been added some iodide and bromide of
potassium. The plate is then inverted on its pneumatic
holder, and revolved by means of a vertical cord attached
to the bottom of that holder, so that by centrifugal force
some of the albumenous coating is scattered, leaving the
thinnest possible film on the glass. The plate is then
dried, as yet insensitive to light. Next it is immersed
in an acid silver bath for about three minutes, and after
washing with several changes of water, a preservative
consisting of a saturated solution of gallic acid, is applied
to it. Drying by gentle heat completes the manufacture
of this form of plate. The development is brought about
by a saturated solution of gallic acid, to which has been
added a few drops of silver nitrate.
We will now give our attention to the beautiful
Collodio-bromide process, a brief description of which is
only necessary, for the collodion emulsion for the im-
112 THE BOOK OF THE LANTERN.
mediate coating of the plates can be bought ready made,
with full instructions for coating and development.
This method yields results which cannot easily be beaten,
It was introduced about twenty years ago by Messrs.
Bolton & Sayce, and a number of good workers have
since taken it up successfully. As its name implies, a
collodion is employed containing bromide of silver, and
although many might be deterred from attempting it, from
the fancied difficulties which it presents ; yet, in practice
it is by no means a complicated process to work. It has
certainly a great many advantages. When the sensitised
collodion is once compounded it will keep for a long time.
Plates can be coated with it a dozen at a time if required
and after being dried by artificial heat are ready for
immediate use. When the printing from the negative has
been performed, these plates, after development and a
minute's washing, can be dried, and the slides are finished
and ready for the lantern.
A plain collodion is first of all made with high tempera-
ture Pyroxyline, and the usual solvents, ether and alcohol.
To this is added ammonium-bromide and citric acid. The
silver is now dissolved in as little water as possible, and is
added to the bromised collodion. The emulsion is then set
aside to ripen for some hours, is poured out into a dish for
the solvents to evaporate, and is then broken up into small
pieces and washed in several changes of water, so as to get
rid of the soluble salts which are not required. All these
operations are, of course, conducted in non-actinic light.
When these pieces have been finally drained as closely as
possible, they are once more dissolved in the requisite pro-
THE BOOK OF THE LANTERN. 113
portions of ether and alcohol, and, after filtering, the re-
constructed emulsion is ready for coating the plates. They
can be developed by a weak alkaline developer with pyro,
or by the ferrous-oxalate method, which will be described
later on, Mr. W. Brooks, of Reigate, has made a study
of this process, and supplies the emulsion ready made.
Messrs, Mawson and Swan have also lately advertised it,
so that it is hardly worth while for the worker to make it
This method yields results which cannot be sur-
passed, but it may be looked upon more as a com-
mercial process than one suited to the amateur worker,
for it necessitates the use of expensive plant. I shall
therefore dismiss it with a somewhat brief description,
albeit my chapters on slide-making would hardly be com-
plete without it, In the first place a relief is obtained by
employing gelatine, containing one of the bichromates of
the alkalies bichromate of potash, for instance. This
relief is placed upon a sheet of lead, and after the two
have been fixed in a steel frame, they are submitted to
hydraulic pressure, with the curious result that the tender
gelatine film preserves its delicate outlines, but the leaden
plate gives way, and these markings are pressed into it.
This leaden plate then forms a mould of the future picture,
its deepest parts representing the shades of that picture,
and its higher parts the lights. This is placed in a special
press, and a pool of gelatinous ink (made by dissolving any
suitable pigment in a warm solution of gelatine and water)
114 THE BOOK OF THE LANTERN.
is poured upon the mould. The square of glass which is
to bear the picture is placed on this pool of ink, and the
pi-ess is lightly brought down upon all. The slide is left
thus until the gelatine has had time to set, when the
glass is lifted from the mould, and the picture in all its
delicate details is left upon it. This beautiful process,
which may be looked upon as the most perfect of all the
mechanical photographic processes, was due to the genius
of the late Mr. Woodbury, who, shortly before his lamented
death, modified it so that it might be practised by ama-
This modification is known as the Stannotype pro-
cess, tinfoil being employed as a substitute for the work of
the hydraulic press. The gelatine relief is attached to a
plate of glass by a suitable cement. Its surface is then
coated with india-rubber cement, and a sheet of ordinary
tinfoil is placed above it. The whole arrangement is now
passed between a couple of india-rubber rollers, such as
are attached to a domestic wringing-machine, so that the
tinfoil is forced into the interstices of the picture, We
thus obtain a metallic-faced mould without the interven-
tion of the hydraulic press, and this mould is afterwards
treated with warm gelatinous ink, and prints taken off, as
in the Woodburytype process. In the latter process, how-
ever, a negative is employed to give the necessary relief,
and in the Stannotype a positive. Both of these methods
give the best results for pictures where there is not a large
expanse of sky, or other high light ; for in such a case
a slight deposit of the pigmented gelatine is likely to spoil
THE BOOK OF THE LANTERN. 115
the transparency of such lights, and in a good lantern slide
they should be represented by clear glass.
TRANSPARENCIES ON COMMERCIAL GELATINE PLATES.
For some inscrutable reason, it used to be the common
opinion among those who ought to know something about
the matter, that the gelatine process is unsuitable for lan-
tern transparencies. The introduction lately of gelatine
lantern plates into the market has done much to correct
this error ; but still there are numerous persons who hold
to the belief that the ordinary gelatine plate, such as is
used for negative work, will not produce a good trans-
parency. For years I have proved the contrary, and with
regard to the quality of the transparencies produced, I have
seen few to equal them.
The first operator who turned out successful work of this
character was Mr. Kennett, who has the greater honour
of being the first to make gelatine plates a marketable
commodity. His method of working was to employ a slow
plate, to expose it under a negative in a printing frame for
the fraction of a second in daylight, or for a longer time
by lamplight, and to develop by either the alkaline or
ferrous oxalate method. The plate was afterwards flooded
with pyro and silver and toned with gold.
The introduction of chloride plates, which give beautiful
effects, may deter some from trying what can be done by
ordinary gelatino-bromide plates. But for the amateur
whose time is otherwise occupied during daylight, the latter
process has many advantages. The chief one is that, while
116 THE BOOK OF THE LANTERN.
the exposure of a chloride plate to lamplight will occupy
about three minutes, a bromide plate can be successfully
exposed in less than three seconds, so that a number can
be exposed in an hour or two.
I have already pointed out how a reduced positive can
be readily obtained from a negative by means of the
camera. I will now suppose that the negative from which
the transparency is to be taken, is on a plate, and, there-
fore, the right size for the lantern slide, and that the pic-
ture is to be printed by contact in a printing frame.
The requirements are a red lamp, a gas or paraffin
lamp, which can be readily turned up and down, and a
As in most photographic operations, correct exposure is
the main consideration, but whereas where daylight is
concerned, this exposure is always difficult to hit upon,
because the light varies so much under different circum-
stances ', here, where we have a lamp to work by, we can
measure its duration to a nicety.
I may mention here that there is a form of gas-burners
sold which is very useful in this work. It is fitted with a
bypass, so that it is never actually turned out. A blue
bead of light remains, which is quite shielded from view,
and this permanent flame ignites the full amount of gas
when the stop-cock is turned on. The operation of print-
ing a transparency consists in placing the negative in the
frame, and placing upon it, film to film, a gelatine plate,
measuring 3 x 3 inches. The frame is closed, and is
held within a short distance of the lamp, which is turned
THE BOOK OF THE LANTERN.
up for a brief period, and then turned down to darkness
once more. But how must this period be measured ? In
order to answer this question I must call attention to a
certain optical law which I have attempted to put in the
form of diagrams :
Fig. 38 illustrates the manner in which the light rays
from a candle strike out all round it like the spokes of a
wheel ; but, for simplicity sake, the rays in one direction
only are shown. Let A represent our printing frame held
at 1 foot from the light source, and let us suppose that
at that distance the plate contained in it will require one
second's exposure. Now let us expose a similar plate at B,
which is 2 feet from the light source, what exposure will
it require? "Two seconds," the tyro will probably
answer ; but he would be wrong, the plate at double the
distance will require four times the original exposure ; at
treble the distance, nine times the original exposure. In
THE BOOK OF THE LANTERN.
other words, " the intensity of illumination on a given sur-
face is inversely as the square of its distance from the source
Fig. 39 will perhaps make the matter still more plain. At
1 foot from the candle the square marked i receives a
certain amount of light ; at u, that light is spread over a
surface four times the area of the first ; and at in over a
surface nine times as large as I. This law, which is really
of a very simple character, the operator should have con-
stantly in his mind, as he exposes his plates, to artificial
light under a negative.
The method of development which I recommend is by
means of ferrous oxalate, and it will be found that the
transparencies produced by- it require no toning whatever.
I make my own potassic oxalate, and find it, moreover,
reliable ; the operation is simplicity itself. In a large
basin dissolve half a pound of carbonate of potash (salts of
tartar) in a pint and a half of warm water. Now add
gradually oxalic acid, a few cr3 T stals at a time, for the
effervescence is very violent, and difficult to control if
much be put in at once. When six ounces of the crystals
THE BOOK OF THE LANTERN. 119
have been so added, set the basin aside for an hour or two,
then stir its contents with a glass rod, and test with blue
litmus paper, adding crystals of acid until the paper turns
slightly red. Add to the liquid 30 grains of potassic
bromide, allow to settle, and bottle off for use when clear.
But those who wish to avoid the trouble of making
their own potassic oxalate can buy the crystals at any
photographic dealer's, in which case its solution should be
made with boiling water, and well stirred until all crystals
have disappeared. One pound of oxalate will require
just a quart of water to make a saturated solution. If
more water be used, the solution will not be a saturated
one, and will, when mixed with the iron, throw down a
muddy red precipitate, and be useless for developing pur-
poses. The iron must be added to the potash, and not vice
versa, or the same effect will be produced. I have found
that with this developer it is always advisable to soak the
exposed plate in water as a preliminary step. The gelatine
surface then takes more kindly to the solution, and greater
density is attained.
The development should be carried on until the picture
looks overdone, for it must be remembered that it has to
be ultimately exhibited by transmitted light, and we view
it in the developing dish by reflected light only, but hold-
ing it up to the red light and looking through it we can
judge well when the developing action ought to be stopped.
Now follows a rapid rinse under the tap, a few minutes'
immersion in alum and water, and fixing in fresh hypo.
If ordinary household water has been used, the film will
show a milky veil. This is quickly removed by a ten per
120 THE BOOK OF THE LANTERN.
cent, solution of sodic citrate, poured on and off, and gently
rubbed upon the gelatine surface with a plug of cotton
wool. This treatment is not necessary if rainwater is
available. Messrs. Mawson and Swan supply an admirable
plate for lantern-slide work. It can be used for reducing
in the camera, or for contact printing, and is amenable to
more than one method of development.
At one of the exhibitions this firm showed a specimen
frame of four transparencies from one negative, each
developed by a different formula, and showing a difference
of tint for each. I was so pleased with their appearance
that I asked for particulars, and the firm kindly supplied
me with the four formulae in question. Here they are :
A. Meta Bisulphite Developer.
B. Carbonate Soda
C. Ammon. Sulphite
D. Ferrous Oxalate
Pyrogallic Acid ... ... ... ... 40 grs.
Meta-bisnlphite Potass 120
Bromide Ammonium ... ... ... ... 40 ,,
Distilled Water 20 ozs.
Liquor Ammonia ... .. t ... ... 2 drms.
Distilled Water 20 ozs.
Mix equal parts of A and B just before using.
Distilled Water up
... 40 grs.
... 40 mins.
to 20 ozs.
Distilled Water . .
. 1 oz. avd.
. 20 fluid.
THE BOOK OF THE LANTERN.
Between development and fixation immerse plate in Sol. of Alum,
1 oz. in 20 ozs. water, washing carefully before and after.
Bro. Ammon. ...
Distilled Water to
Mist. Ox. Potass
... 20 ozs.
Liq. Ammonia, 880 ...
Distilled Water ...20
... 20 oz. avd.
6 oz. avd.
Add 7 parts of I. to 1 part of II. just before using.
LANTERN SLIDES FROM PAPER PRINTS ENGRAVINGS OB
There are certain main principles to be observed in
copying a photograph, or anj other kind of picture, if a
satisfactory negative, fit for printing a lantern slide from,
is to be expected. The copy should be illuminated by
diffused light only, and should never receive the direct
rays of the sun. A cloudless day is the best to choose,
for then the light is regular, and when the exposure has
been correctly calculated for the first picture, it will, during
some hours of the day, be right for the rest. At least this
is true, if we are copying a series of pictures of the same
dimensions. But, if our first copy is, say, 12 inches across
and our next one only carte de visite size and we want to
reproduce a negative of each, measuring 3J x 3J (the
standard size for lantern pictures), our camera must in the
122 THE BOOK OF THE LANTERN.
latter cases be so much extended that the exposure must
be proportionately increased.
A picture under glass will seldom give a good result,
for the surface will take up reflections from surround-
ing objects, which may not perhaps be noticed on the
focussing screen, but which will most surely become dis-
agreeably evident in the negative. A highly glazed
albumenized print is objectionable for the same reason,
but can be generally coaxed into a position in which no
mischief of the kind is apparent. Steel engravings have no
gloss, but they seldom make good pictures for the lantern
screen, their details being too fine. A first-class wood
engraving is far better for the purpose, and as its value is,
as a rule, not very great, it can be judiciously touched up
before being photographed. Perhaps the artist of such a
picture would be horrified at his work being thus interfered
with, but the touching up indicated is quite legitimate.
Let me further explain my meaning. Suppose that in one
of our illustrated periodicals there is a representation of
some current event which we want for our lantern. If it
is an interior view, it will probably require no doctoring. But
if a landscape, or a group of figures with a sky back-
ground, then certain parts should be suppressed. The sky
is not white, but consists of a number of parallel lines with
clouds interspersed ; effective enough in the print, but not
suitable for reproduction in an enlarged form. These lines,
which seem to mingle so well, giving the effect of a general
soft " tint," will on the lantern sheet look like what they
really are a series of detached bars right across the picture.
To get rid of these lines, the outline of the figures, and
t THE BOOK OF THE LANTERN. 123
other objects which stand against the sky, should have a
broad margin painted round them in Chinese white, leaving
the main body of the sky to be blocked out with black
varnish in the negative itself.
I have done excellent work with Ross's portable sym-
metrical lens No. 3 which has a focus of 5 inches. Of
course, other lenses will do well for copying, but if of
longer focus, the camera must have an extending front
fitted to it. Very few cameras pull out long enough to
photograph a very near object, unless a short focus lens is
employed. As a guide to exposure, I may mention that
in copying wood-cuts and photographs with the above-
named lens, and using a fairly-rapid gelatine plate, it
averages 17 seconds with stop No. 4. It is as well to focus
with full aperture of the lens, and to insert the stop just
before exposure. One more hint. It is sometimes very
difficult to sharply focus a soft photograph which has no
sharp lines in itself. The difficulty is obviated by affixing
to the middle of the copy any little piece of printed matter,
wetting it with the tongue for that purpose. Only be
careful to remove it before exposure, or your negative will
faithfully record the little dodge.
It would seem a very simple matter, to one who has not
tried it, to fasten a picture upon a wall in a good light,
stand the camera on its tripod in front of that picture, and
proceed to copy it. But difficulties crop up when we want
to reduce that picture to a certain size, and to keep the
camera square with the copy, so as to prevent distortion.
With head beneath the focussing cloth, the struggle to
adjust the tripod legs is quite distressing. I myself found
THE BOOK OP THE LANTERN.
so much difficulty in getting the camera into the exact
position required, that I constructed a special piece of
apparatus for the sole purpose of copying. To this acces-
sory, which works most perfectly, I now direct atten-
tion. It is simple in construction, and anybody who knows
how to handle a few tools can put it together with ease.
The amateur may prefer to employ a professional carpenter,
but there is always a difficulty in getting the British work-
man to make anything that is at all strange to him. My
advice is, therefore, if you want the thing done well, do it
yourself (see fig. 40).
THE BOOK OF THE LANTERN. 125
A is a base board, fixed on legs, as shown. It will be
evident that a spare table, or even the top of a packing-
case, would do as well, but it must be firm. Upon this base,
and fixed firmly to it, is a kind of railway formed by two
parallel grooves. D is a skeleton carriage furnished with
two runners at the bottom which will fit the grooves in
A, so as to run easily to and fro. The carriage D is also
furnished with grooves, and these are for the reception of
the runners affixed to the super-carriage, E. Upon E is
fastened the photographic camera, the camera screw being
placed through the centre hole for that purpose.
In use, the picture to be copied is pinned to the back-
board, F, and I may mention as a detail of some im-
portance, that the little bead-headed arrangements known
to drapers as " ladies' bonnet-pins " are best for the purpose.
The camera is placed on E, E on D, and D placed on the
rails of the baseboard, A. We thus have two separate
movements at our disposal in getting the image of the copy
focussed centrally on the ground glass. A furnishes the
to and fro movement, and the grooves on D give the right
and left movement. The board, F, runs between upright
grooves, and thus we have a vertical movement. With
this simple contrivance a picture can be focussed in a few
seconds, and the camera all the time is bound to keep square
with the copy. A 3 -inch circle drawn in pencil on the
ground-glass of the camera is useful as a reminder of the
size to which the picture must be reduced.
Lastly, this useful contrivance can serve another pur-
pose. We may wish to obtain a reduced positive on glass
from a larger negative. We can do this direct in the
126 THE BOOK OF THE LANTERN.
camera by placing the negative to be copied in an opening
in the board, F, marked by a dotted line in the illustra-
tion. A couple of laths can then be placed above, so as to
rest at one end on the camera, and at the other end on the
top of the board, F. These laths will serve as a support
for a dark cloth, which can be thrown over all. A sloping
piece of white cardboard placed behind F (also indicated
by a dotted line) will throw reflected light from the sky
through the negative. I give no dimensions for this copy-
ing machine, for the maker must be guided by the size
of his camera, the focus of his lens, and his general
requirements. A compound frame for negatives of various
sizes, as shown in fig. 41, makes this copying-machine
HOME-MADE GELATINE PLATES.
ILL makers of commercial gelatine plates put for-
ward the quality of rapidity as being the one
thing needful in modern photography, and ad-
vertise their wares as being ten, twenty, or even sixty
times as quick in operation as the old wet collodion
process. Such rapid plates are not the best for trans-
parency work, and as no maker will acknowledge that
his plates are slow, although opinions may be divided
upon the matter, and as slow plates are the most
suitable for lantern slides, the operator who aims at the
best work may wish to try his hand at making them for
himself. Of the many formulae which I have tried for this
particular purpose, I prefer that first introduced by Dr.
Eder, which I have slightly modified. Gelatine plate
making is by no means easy work, but the method which
I am about to describe presents fewer difficulties than
The apparatus required need only be of a very homely
128 THE BOOK OF THE LANTERN.
nature, and such as can be found in most households.
Here is the list : An earthenware pot with a cover to it,
of about one pint capacity ; a glass tumbler ; a preserving-
pan or saucepan standing on a tripod, with a spirit-lamp
or Bunsen flame beneath it; a thermometer, two glass
stirring rods, a square of Berlin-work canvas, an earthen-
ware colander, and a dish. In the earthenware pot put
the following :
Gelatine ... ... ... ... 110 grains.
Potassic Bromide... ... ... 62 ,,
(Ten per cent.) Solution of Salicylic Acid in Alcohol, \ ounce.
Water ... ... ... ... 2 ounces.
I recommend the use of either Autotype, the Swiss, or
Henderson's make of gelatine. After being weighed it
should be cut up into strips with scissors and placed in the
jar with the other ingredients. With a glass rod press
down the gelatine into the water, so that every particle of
it is wet and softened. Set aside for ten minutes to swell.
Now half fill the preserving-pan with warm water, and
place the flame beneath it. The thermometer should be
placed in the pan, so as to check the temperature, which
should not be allowed to rise about 96 Fahr. Place the
pot containing the gelatine in the water, taking the precau-
tion to put a piece of thick paper beneath it, so that it
does not actually touch the heated bottom.
The gelatine will very gradually melt, and the opera-
tion may be hastened by an occasional stir with the glass
rod. Even when it becomes quite limpid, little particles
of undissolved gelatine may be floating about in it
and these should disappear before proceeding further, or
THE BOOK OF THE LANTERN, 129
they will form insoluble particles, which will lead to
difficulties later on. In the glass tumbler place
Silver nitrate ... 77 grains.
Water ... ... 2 ounces.
The common tap water employed will, on account of the
salts which it contains, turn milky in appearance when the
silver is added. This is of no consequence. The crystal*
can be crushed under the water by another glass rod,
and complete solution will soon be effected. (The tyro
must be most careful to keep each stirring rod distinct, or
he will spoil the entire work.) When the crystals have
all disappeared, pour into the silver solution, drop by drop,
some strong liquid ammonia, stirring the solution vigorously
all the time. The liquid will turn coffee-coloured, owing
to a precipitation of silver oxide, but as more of the
ammonia is added this precipitate is redissolved, and the
solution becomes as clear as ordinary water. Only just
sufficient ammonia should be added to accomplish this
result. Now place the glass tumbler in the pan beside
the vessel containing the gelatine mixture, and leave it
there to warm for about fifteen minutes. All the fore-
going operations can be conducted in the full light of day,
but now, when the two solutions have to be blended to form
a sensitive emulsion of bromide of silver, the light of the
red room only must be called into requisition.
The flame beneath the pan, or water bath, is now no
longer required, so let it be removed. Take both the gela-
tine and silver vessels from the pan, and place them on the
table. Now stir the gelatine briskly, and add a small
130 THE BOOK OF THE LANTERN.
portion of the silver solution at a time, until all of it is
transferred to the earthenware pot. Wash out the silver
glass with half an ounce of water and add that too. The
newly-formed emulsion should now look like cream. Place
the cover on the jar, and put it back once more in the
warm water (without any flame beneath it) for fifteen
minutes. At the end of that time pour it out into a dish
or plate to set, and cover it over so that neither light nor
dust can trouble it. This will complete the first stage of
In a few hours, according to the general temperature,
the emulsion will have set into a firm jelly. It must
now be washed to get rid of certain extraneous matter
which has been formed and which is not wanted. The
silver nitrate has combined with the bromide of potassium
to- form silver bromide, the required salt, which is sensi-
tive to light, but at the same time nitrate of potassium
(saltpetre) has also been formed, and must be eliminated.
As this latter is soluble in water, while the silver bromide
is insoluble, the matter is not a difficult one to accomplish.
By dividing the jelly into shreds, and putting it into
several changes of water, this universal solvent gets to
every side of it, so to speak, and the saltpetre is quickly
got rid of. Scrape up the jelly with a silver spoon, or a
slip of glass, and place it in the middle of the square of
canvas, which has been previously wrung out in water.
Gather up the ends so that the jelly forms a ball confined
within the canvas. Now place in a large pan of water,
and squeeze and twist the canvas with the hands (under
water) so that the jelly is forced through the meshes of the
THE BOOK OF THE LANTERN. 131
fabric like so much vermicelli. It will presently sink to
the bottom of the pan. Now pour off the water above it,
and fill up with fresh. Let the pan rest for five minutes,
and repeat the operation half a dozen times. The emulsion
must now be strained.
A square of cambric, the size of a handkerchief, is
squeezed in water, and put in the colander, so as to form a
lining to it, with the corners hanging outside. Pour the
divided emulsion into this, when most of the water will
at once run off, and still more may be made to do so by
gathering up the corners of the cambric in the hands and
gently squeezing the pudding-like mass. Once more open
the cloth, and pour into the contained emulsion an ounce
of methylated spirit. Again squeeze up the cloth, after
which the gelatine shreds can be spooned up, placed in a
clean jar, and tied over with a light-tight cover. So ends
stage number two.
There are many who say, with much truth, that the real
difficulty of plate-making begins after the foregoing opera-
tion of making the emulsion, for a great many fail in the
mechanical work of coating the plates, which is the next
and final operation. Before this is attempted the decks
should be cleared for action. The operator must have on
his table a carefully levelled piece of slate or plate glass,
large enough to contain at least one dozen plates, laid
edge to edge. He will also want a jug with a good lip
from which to pour the emulsion, a glass rod to guide
it over the plate which he is coating, and a pneumatic
holder. The jar of emulsion must first of all be placed in
the water bath at the old temperature of 96 for an hour
132 THE BOOK OF THE LANTERN.
or two, during which time it can be conveniently stirred
once or twice (by red light only, of course). If the cover
of the jar be really light tight, this melting operation can
go on in daylight, and at the same time the glass to be
coated can be cleaned. Polish each glass with a little
whiting and water, and when dry rub the side to be
coated with a leather damped with spirits of wine. This
will counteract any repellant action when the emulsion is
applied to the glass surface. When all the glasses have
been so treated, wrap them in packets of two dozen each,
in clean paper, prepared side upwards, and put them on
the kitchen hob to warm through. (This latter precaution
is only necessary in cold weather.) The emulsion must
now be filtered.
The best form of filter is a lamp chimney with a flange
on its lower orifice, over which a piece of damp wash-
leather (which has been washed in soda and rinsed in
many changes of water) can be tied. When all is ready
for commencing to coat, this filter is held over the mouth
of the jug (both should be rinsed out with warm water
the instant before), and the emulsion is poured steadily into
its upper opening. In a minute it will run through the
leather into the jug below, and will be quicker in its move-
ment if a pressure of air is kept upon it, by applying the
lips to the upper end of the glass. Now comes the coating
Let the operator seat himself at his table so that the
slate or glass slab is between him and the red light.
Place the glass rod in the jug of emulsion, and when in
the act of pouring keep the rod back with the thumb of
the same hand that is holding the jug. Take the topmost
THE BOOK OF THE LANTERN. 133
glass plate, fix it on the pneumatic holder, hold it level,
and ponr a small pool of emulsion in its centre. By inclin-
ing the plate a little, the pool will run to the two further
corners, and can afterwards be guided across the whole
plate with the help of the glass rod. The plate is then
slid on to the slab, where it will speedily set, and the glass
rod goes back into the jug. Each plate is treated in the
same way until the slab is full, by which time its first
occupants will have set, and can be reared up to dry in
shelves, or a proper drying cupboard. The glass chosen
should be as thin and as free from bubbles as possible, and
can be of the standard lantern size, 3 J by 3J inches. But
as experience is gained the operator will find it more con-
venient and economical of time to coat plates 6 J by 6 \ inches,
which can afterwards be cut across twice with the dia-
mond, to form each four lantern slides.
My own favourite process for lantern slide making is the
gelatine-chloride, which has many good points to recom-
mend it. It is suitable only for contact printing, there-
fore the negatives used must be small ones only. Capital
chloride plates can be purchased nowadays ; but for those
who prefer to make their own, I can confidently recom-
mend the following formula : Mix up the three solutions
A, B, and C.
( Water (distilled) ..
Water (distilled) ..
Water (distilled) ..,
134 THE BOOK OF THE LANTERN.
Melt by heat, but not above 120 Fahr. Then in a
yellow light, pour B into A, stirring rapidly all the time,
and finally adding C. Allow the emulsion thus made to
remain for one hour, at the temperature already stated,
and then put aside in a dish to set. The washing, filtering,
and coating operations are the same as those described for
bromide plate making. The bright yellow light allowable
is a great help to comfortable working of this process.
Chloride plates are useless, on account of their slowness,
where a slide has to be reduced, by means of the camera,
from a negative larger than itself. Nor do I advise the
amateur to adopt them unless he can work by daylight,
or is fortunately situated like one I know, who lives oppo-
site to an enterprising tailor who displays an electric arc
light in front of his door. For the chloride plate is most
insensitive to yellow light, such as that afforded by gas.
For this reason, most commercial makers advise that the
light chosen should be that procured by burning an inch of
magnesium wire at a distance of so many inches from the
printing-frame. This advice is not difficult to follow, but
it is very difficult to make two pieces of wire give out
exactly the same amount of light ; for magnesium wire has
a habit of dropping down in a languid manner under the
influence of its own heat, and going out suddenly when it
ought to shed its radiance abroad. With diffused daylight
all is plain sailing. The negative, with its chloride plate
in contact with it, is exposed, say, for three seconds to
daylight, and is then dropped into the developer. Here
is a good one, devised, if I remember rightly, by
Mr. Edwards :
THE BOOK OF THE LANTERN. 135
C Neutral potassic oxalate ... ... 2 ounces.
A 3 Sal ammoniac ... ... ... 40 grains.
( Water (distilled) 1 pint.
f Iron sulphate ... ... ... 4 drachms.
p. \ Citric acid ... ... ... ... 2
B 1 Alum 2
(. Water (distilled) 1 pint.
For use, pour a portion of B into an equal quantity of A.
If the operator is accustomed to the ferrous oxalate
developer pure and simple, he will find that it will develop
this description of plate, but it is better for being restrained
with a few drops of 10 per cent, solution of sodic citrate.
Whether he use one or the other, let him be particularly
careful in the matter of cleanliness of fingers. A hypo-
defiled finger will spoil the developer instantly. To avoid
this disaster, the potency of which I have learned by
sad experience, I have adopted the following method of
I use a brilliant yellow light, so that I can work comf ort-
. ably, for chloride plates are, as already stated, insensitive to
yellow rays ; the developing tray stands in front of it, and at
one side is placed a large tray filled with water, to which a
little alum solution has been added. Hypo is, for the pre-
sent banished from the scene altogether. I expose my plate,
and put it into the developing solution. In a few seconds
the picture flashes out in the unceremonious manner com-
mon to chloride plates. I hold it up to the light, look
through it, and find that it is but a ghostly image after all.
I expose another plate in an adjoining room, and put it by
the one which is in course of development, and which by
this time has most likely gained sufficient density. If it
has, I wash it for a few seconds under the tap, and drop it
THE BOOK OF THE LANTERN.
into the alum tray ; and so on, until perhaps a couple of
dozen plates have been treated in the same way. I then
light my gas-lamp, mix up a tray of fresh hypo, large
enough to accommodate half a dozen plates at a time, and
proceed to fix my plates. They fix rapidly, and as fast as
they are done, back they go into the weak alum solution,
until, when the batch is finished, I proceed to wash them.
This I do by placing them in a metal rack (see fig. 42),
and changing the water occasionally during an hour or so.
GENERAL CONSIDERATIONS INTENSIFYING AND MOUNTING.
Hitherto I have said nothing with reference to the best
kind of negative for lantern- slide making ; the worker will
find out, after a few trials, that some of his negatives will
yield, without much trouble, a first-class result, whilst others
THE BOOK OF THE LANTERN. 137
seem reluctant to give anything but a very poor trans-
parency. A really good negative will give a good print
on paper, glass, or indeed on any other possible material,
but at the same time a negative, which from its thinness
would require special management in ordinary printing on
albumenised paper, will yield a fine transparency on glass
with half the trouble. In other words, a negative taken
purposely for lantern work need not be so dense as one
destined for the ordinary printing-frame. The precautions
used in dealing with a thin negative in the one case, must
be observed in the other ; for instance, the careful printer,
in producing a paper print from such a negative, will take
his frame far from the window of his room, and give it a
very protracted exposure, and, by coaxing it in this way, a
good dense print is obtainable. Exactly the same treat-
ment is necessary in producing a lantern-slide from the
same picture. Instead of holding the printing-frame a foot
or two from the gas-burner, as already recommended, let it
be removed 6 feet away from the flame, and be given a
greatly-increased exposure by the rule already indicated.
I have advised that the focussing-screen of the camera
should be marked with a 3-inch circle, to which the
picture should be limited. A still more effective plan,
however, is to cover the ground-glass with a card-
board mask, having a 3-inch hole in its centre, which
can be placed in situ when required. The operator can
then see at a glance whether his picture is nicely composed,
and will have a very good idea of its ultimate appearance
as a lantern-slide on the sheet. Most photographers carry
into the field with them more than one lens, and it is espe-
138 THE BOOK OF THE LANTERN.
cially necessary that he whose negatives are intended to
yield lantern-pictures of a uniform size should do so. The
beginner is, perhaps, not likely to see the advantage of this.
Let me point it out. Suppose that he has focussed the
image of some wayside cottage, and finds to his chagrin
that the building fills up all the proscribed circle, and that
the surrounding foliage and other accessories which really
make up the beauty of the scene, as presented to the eye,
are "far, far away." His natural impulse would be to
carry his camera farther from the object, but a blank wall
behind him forbids him to do this. But with a shorter
focus-lens, which should screw into the flange fitted on his
camera, the accident can be immediately remedied, and
he can proceed on his way rejoicing. This same difficulty
has occurred to me time after time, in the case of
country churches having small burial-grounds shut in on
every side by foliage. From no point can a view of the
building be focussed on the glass except by using a lens of
very short focus. Very often the conditions are reversed,
and the photographer finds himself before a scene with some
obstacle in front of him which forbids nearer approach,
and the image on the focussing- screen is quite insignificant.
Here the obvious course is to-screw off the front lens of his
combination, and to treat the back one as a long-focus
single lens. Of coarse, the camera must be extended to
double its normal length, and no amateur should possess a
camera that will not do so, should occasion require it.
The most experienced workers often obtain a negative
full of brilliancy and delicate detail, but with a very thin
sky, a sky so thin that if a lantern-slide were taken from
it raw, so to speak, we should have in it a very good repre-
THE BOOK OF THE LANTERN. 139
sentation of a November fog. There are several ways of
obviating this difficulty. In exposing it before the gas-
flame it should, like all thin negatives, be taken several
feet distant, so that the time of exposure may perhaps
extend to twenty seconds or more. During this time keep
the sky portion covered with a piece of card which has
been cut in Vandykes all along the edge next the horizon,
but do not keep it still, but in gentle movement. This
plan gives a clear sky, with the effect of a slight haze over
the horizon, an effect, I need hardly say, frequently seen
in nature. Indeed, this hazy effect can often be extended
to the landscape itself, with the most charming effect of
atmosphere which an artist could desire.
Another plan of treating a thin sky is to furnish it with
clouds by the following simple method: Paste over the
glass side of the negative a piece of white tissue paper.
When this is dry, hold it up to the light, and mark upon it
the position of the horizon and the outline of any trees or
other objects which may appear against the sky. Now,
with a stump and a black pigment (such a pigment for use
with the stump is sold by most artists' colourmen, I do
not know the name) rub in masses of cloud, taking care
that their edges are ill-defined and fleecy. By this means
a flat, tame -looking negative can be made to yield a beau-
tiful picture. Any water in the composition can be treated
in the same way, for it must be remembered that water
reflects clouds as well as anything else. Where the sky is
dense enough, but contains pin-holes or other blemishes,
Bates's black varnish, painted on the plain glass side, is the
best remedy; or the faults can be delicately stopped out
by ordinary India ink on the film side. Where there is a
140 THE BOOK OF THE LANTERN.
large expanse of sky, the quickest method is to gum over
it a piece of orange-coloured paper with a jagged edge.
A lantern slide, otherwise perfect, will sometimes re-
quire a little strengthening. I believe that the best
method of intensification is that long ago published by
Mr. England. Here it is :
Mercuric bi-chloride (corrosive sublimate) ... | oz.
Sal ammoniac ... ... ... ... ... \
(Dissolve, and mark " Poison.")
The picture, after well soaking in plain water, is im-
mersed in this mixture, in which it will first turn grey,
and afterwards quite white if left long enough. The
white stage should not be reached unless a very great
additional intensity is requisite. Remove from the solu-
tion, wash most thoroughly under a tap for three or four
minutes, and immerse in the following solution, which will
almost immediately turn the film to a brown black :
Liq. ammonia-fort ... ... ... ... drachm.
Water ... ... ... ... ... ... Bounces.
Rinse under the tap, and the operation is complete. Many
people object to the use of the mercuric salt, on the
ground that it is unstable, and that the picture will ulti-
mately fade. I have not found this to be the case if the
washing operation be thoroughly carried out, but as a rule
I should give an intensified film a protecting layer of
varnish. Prevention is better than cure, and the amateur
should endeavour to produce pictures that will require no
When the lantern transparency is complete it must be
mounted before it can be considered out of hand. It is as
THE BOOK OF THE LANTERN. 141
well to try it in the lantern first, in order that any little
blemish not before detected can be remedied. Any little
clear spot where a clear spot has no business to be can be
touched with India ink. If the picture is to be coloured,
the slide need not be so firmly bound up as one to be used
plain. A cover glass, separated from the photograph by a
paper mask, with a round, square, or cushion-shaped open-
ing, and fastened with one or two slips of gummed (stamp)
paper, is quite sufficient until the artist is ready with his
palette and brushes. But if the slide is to be exhibited as
a plain photograph, it may as well be bound together as it
is to remain. For this purpose we require slips of gummed
paper fourteen inches long by three-eighths of an inch
broad. The paper (black needle paper is the best) should
be gummed before being cut, and one sheet will provide
for about a hundred pictures. Mix powdered gum arabic
with one fourth its weight of loaf sugar, and add sufficient
water to make a thick mucilage. Paint the paper liberally
with this, and hang it up to dry. When dry it can be cut
into slips of the above size.
To mount a picture, damp one of the slips of gummed
paper, and put it sticky side upwards on the table before
you. Now take a slide, duly fitted with its black mask, and
a cover glass, all perfectly clean and free from dust. Hold
the combination tightly between the fingers, and bring one
edge down on the end of the gummed slip. Now treat the
slide as a porter treats a heavy box, turn it over and over
along the slip of gummed paper, so that each edge will
take up its quantum. Now carefully fold down the edges,
neatly adjust the corners, and the thing is done.
142 THE BOOK OF THE LANTERN.
The black masks can be bought ready cut at about three-
pence the dozen, or the worker can cut his own if he prefer
it. Zinc patterns are sold for this purpose, together with a
clever cutting tool, which consists of a little steel wheel set
in a handle (see fig. 43). The pattern is placed above the
paper to be cut, the little wheel is run round the opening
in the zinc, and a cleanly cut mask is the result. A sheet
of glass is the best bed upon which to lay the paper when
cutting it. The gummed slips can also be bought, but
those who prefer to be self-dependent will make their own
in the way described.
Not long ago I compared one of my slides with a wet
plate one taken from the same negative by a first-rate
operator, who is used to this class of work, and hardly
does anything else. He was bound to admit that the
gelatine picture was the better of the two, and said that he
should think of relinquishing his bath after seeing what
gelatine plates could do. I advised him to do no such
thing. A wet plate is so certain in its results, that an
unskilled hand, if he be furnished with the materials, can
produce picture after picture without difficulty. I cannot
say the same of gelatine plates, for they are such ticklish
things that oftentimes something or other will go wrong.
THE BOOK OF THE LANTERN. 143
But for the amateur worker, to whom a few failures are
not of any great moment, gelatine plates are best adapted.
The silver bath, with its concomitant stained fingers and
spoiled linen, is, I think, best left alone, unless the ama-
teur adopts it as a necessary part of his photographic
Those amateur photographers who are used to the work-
ing of bromide paper, can produce lantern slides by an
easier method than any of those just reviewed, namely, by
means of the transferro-type paper which has lately been
introduced by the Eastman Company, and with which
many succeed in producing very fine lantern slides. This
paper is coated with identically the same emulsion as that
employed in the well-known bromide paper, and therefore
the amateur has an advantage at the outset, of working
with a medium to which he is accustomed ; its develop-
ment being the same as that of the ordinary bromide paper.
It consists of an insoluble sensitised emulsion which is
applied to paper having a soluble substratum of gelatine.
The tissue is exposed under a negative to gaslight for
the requisite time, and according to the density and
other peculiarities of the negative in question ; and is then
developed in a ferrous-oxalate solution in the ordinary
manner. It is then transferred to a piece of plain glass,
which should be free from bubbles and other blemishes,
while wet, being placed face down on the glass, and
squeezed into contact. As much moisture as possible is
then removed by the application of blotting paper. In
about half an hour it will be ready for stripping ; but may
144 THE BOOK OF THE LANTERN.
be left if preferred until the tissue is quite dry. The glass
and its print is placed in a dish containing water at
the temperature of about 110 degrees if the print is wet;
but should the print have been allowed to dry, the water
must be some 10 degrees hotter. After allowing it to soak
for a couple of minutes or so, the paper is raised at one
corner, taking every precaution not to injure the sur-
face; when it will readily separate from the film. The
plate bearing the picture is then put into a solution of alum
for a minute, and is placed in a rack to dry. Upon ex-
amining a lantern slide so made, a slight granular appear-
ance is observable in the high lights and the sky ; but this
is not apparent when the image is projected on the lantern
screen. The picture will have the usual grey tone, which
is associated with f errous-oxalate development ; but it can
be turned to a rich brown by the following treatment :
. ( Potassium ferricyanide ... ... ... 100 grs.
(Water 24 ozs.
T, (" Uranium nitrate 100 grs.
15 (Water 24 ozs.
Take equal parts of A and B and immerse the print in
the mixture until the tone changes to the tint required.
Then wash thoroughly and immerse for five minutes in a
freshly made-up solution hypo, three ounces ; water, six-
teen ounces, wash. The prints that will best yield to this
after-treatment are those in which the image is from any
cause rather weak ; for this final bath not only alters the
tone, but acts as an intensifier.
ON COLOURING PHOTOGRAPHIC TRANSPARENCIES FOR LANTERN
giving directions for colouring lantern trans-
parencies, I am quite aware that many persons
will say at the outset that a good photograph is
better without any colour at all ; on the principle, I suppose,
that " good wine needs no bush."
I quite agree with that opinion, and in colouring a trans-
parency of good quality, I should be inclined to describe
the operation more as tinting ; for the common method of
colouring by which photographs are blotted out and
drowned in a mass of pigment is simply atrocious. I
lately saw a photographic transparency for a lantern, which
was very beautifully and tastefully tinted, evidently by an
The owner of this picture saw no beauty in it, but com-
plained to me that he paid a long price for this thing, and
there was hardly any colour on it, just as if payment ought
to go by the amount of pigment stuck on the glass.
146 THE BOOK OF THE LANTERN.
In the first place, the worker must consider which of
his pictures will be benefited by a coating of colour,
for some subjects are very much better left alone,
and shown as untouched photographs. This is especially
true of such pictures as exhibit a mass of detail entirely
covering the glass ; a woodland scene, for instance, with
tangled masses of branches and underwood, and ferns in
profusion. On the other hand, if the subject be an open
landscape, with more than half of it consisting of white
sky, it is undoubtedly improved by being tinted. The
white sky receives, with great benefit, its natural tint of
blue, relieved by masses or feathery tufts of clouds,
which, if carefully introduced, can be made to look very
like the real thing.
In the directions that I am now about to give, it may
therefore be taken for granted that all colour is to be put
on most sparingly, and that its' amount must not be suffi-
cient to obliterate the least detail in the photograph. Of
course, if a bad photograph is to be coloured instead of
being thrown into the dust-hole, which latter is by far the
better course, colour can be piled on to it to hide its
inherent defects, but this is only justifiable when the colour-
ing is a necessity, and there is no time to procure a better
Let it be understood that this work of colouring lantern
transparencies is not easy. It not only requires a steady
hand and good eyesight, but it wants artistic perception
also, at least, to do it well. I do not say that a knowledge
of drawing and painting is absolutely necessary to the slide-
painter ; but it is certain that he who understands the use
THE BOOK OP THE LANTERN. 147"
of any kind of colours, and has some knowledge of the way
in which they can be combined to form different tints, will
paint a slide very much better than one who is without
that knowledge. Should he be quite unused to working in
colour, he had best begin by procuring some book upon the
general theory of colouring, so that he may understand the
difference between a primary, secondary, and tertiary tint, .
and may learn how to combine them together. There are
plenty of such books to be had, and very often the infor-
mation is comprised in some of those useful little manuals
on water-colour painting which can be had of most artists'
colourmen. I say water-colour painting advisedly, for the
art of slide-painting partakes more of that kind of art than
any other ; for the reason that it deals with transparent pig-
ments. But do not let it be imagined that I recommend
vvater colours for the work in hand. I know that some
writers have advised their use, and there is more than one
nanual which describes how slides can be painted in water
colours. The process may possibly have answered under
the old conditions, when the majority of lantern slides Were
made by the wet process, and when the artist had a layer of
collodion to paint upon. But most of my readers will wish
to colour their own productions ; and as these will probably
consist of gelatine pictures, which any application of water
will blister, I will at once reject that method of painting as
First, I will make a few remarks with regard to the
apparatus required, which is of the simplest description.
A retouching desk will make a good easel (see fig. 44), or,
failing this, one can readily be made by using a sheet of glass-
148 THE BOOK OF THE LANTERN.
in a frame. A small school slate measuring about 8 by 5,
with the slate knocked out, and a piece of window-glass put in
its place, makes a very good easel for slide-painting. This
should be hinged on to a base board with a strut at one
side, so as to keep it at a convenient slope for working. A
sheet of white paper placed on the base board at the back
completes the arrangement.
Beyond the easel we shall require a palette, and a white
tile answers the purpose as well as anything else ; some
brushes, a few colours, a sheet or two of white tissue paper,
and a piece of linen cloth upon which to wipe the brushes.
One or two bottles containing different media will complete
the list. The colours employed are those used by artists
for oil painting, and which are enclosed in collapsible metal
tubes. But, unlike the oil painter, the lantern-slide artist
Is confined to the use of those colours only which are
naturally transparent. To make this clear, let us suppose
THE BOOK OF THE LANTER'X, 149 1
that any one ignorant of the subject were to attempt
to use such a colour as vermilion, which is opaque ; it
would appear to be of the usual vivid scarlet when seen on
the glass, but seen through the glass, it would simply be a
black patch, because the light cannot filter through ik
This being the case with all the opaque colours, we there-
fore discard them. I now annex a list of colours which are
at the disposal of the slide-painter, and which are all more or
less transparent. They are not all actually essential, but
still the artist will do well to procure them, as they will
give him an immense variety of tints :
Prussian Blue Brown Madder
Indigo i Rose Madder
Italian Pink Purple Madder Af
V" Raw Sienna v/ Crimson Lake
V^ Yellow Lake Ivory Black
Chinese Orange \ Burnt Sienna
,/ Neutral Tint McGilp.
\f Brown Pink
It will be noticed that there is only one brilliant blue in
this list, that is Prussian blue. For landscape work this
blue is used, perhaps, more than any other colour ; for skies
always, and it enters into the composition of the various
greens, and forms useful tints with most of the other pig-
ments. It is not the colour which an artist would choose by
preference with which to depict the tender tints of the sky,
for, truth to tell, it has a greenish hue, and is rather cold
and repellent in character ; but it is really the only blue
which can be laid on the glass in a flat, even tint, and
150 THE BOOK OF THE LANTERN.
therefore we must make the best of it, such as it is. We
have a far larger choice in yellows, for no less than four of
the colours quoted are, in spite of their names, yellow in
tint. These are Italian pink, the most useful of all
Raw sienna, not nearly so pure a colour ; Yellow lake,
rather a difficult colour to work with ; and Chinese
orange, a most valuable and rich tint. Brown pink may
also be described as a yellow, and brown madder has also a
great deal of the same colour in its composition. The reds
represent a great difficulty to the slide-painter, for, although
they appear to be very rich when spread on canvas, they are
very weak colours when we come to look through them in
a transparency. It is next to impossible to produce a real
scarlet as a transparent colour, but the nearest approach to
it can be made by using Chinese orange mixed with crimson
lake. A great variety of browns may be obtained by com-
bining burnt sienna with the other colours, and the ivory
black will be found most useful in this service. The best
brushes for general work are those of camel-hair, which
have the further advantage of being cheap. But a few
sables will be wanted for delicate markings.
A thing of first importance is the selection of a suitable
medium with which to mix the tints. Canada balsam in
turpentine is of great value. Another good one, which I
believe many slide-painters use almost exclusively, is made
by diluting copal varnish with turpentine, while for dark
colours, japanners' gold size, diluted in the same way, is an
excellent medium, and is of special use in the foreground.
The colour should ba mixed up on the palette with the
medium selected with a proper palette-knife, so as to form
THE BOOK OF THE LANTERN. 151
what is in reality a coloured varnish ; and this must be
quickly applied to the picture before it has time to thicken
by evaporation of the solvents.
For greens, to be used mostly in foliage and for grass,
yellow and blue must be mixed together in varying pro-
portions. There is no such thing as a satisfactory trans-
parent green which can be bought ready made, and suit-
able for the purposes of the slide-painter ; but the use of
the two colours named, if we take care to vary the pro-
portion of each, can be made to give a great variety of
tints. But it should be pointed out that, if used alone, this
compounded green will be far too raw, and will exhibit a tint
which is never seen in nature.
We mix, therefore, with the yellow and blue, some red
or brown, to take off this rawness. An endless variety of
tints may be made by taking three colours only, and using
them in different proportions, and I would advise the slide-
painter to mix some of these tints, and put them side by
side on a bit of glass, with a ticket attached to each
describing their constituents. This specimen glass will be
useful for future reference. I give in the next chapter a
few compound tints, which can be made easily, and can be
used for foliage, etc.
The list of colours given will be found more than
sufficient for all needs, and many slide-painters do very
good work with only half their number, for there is no
limit to the number of tints which one may get by
judicious blending. Mathematicians are able to tell us
the number of chances against a whist-player turning
up the same cards on two different occasions, and we
152 THE BOOK OF THE LANTERN.
know very well that the odds against such an occurrence
amount to an enormous figure, but no mathematician
would be able to calculate the number of different tints
that we can procure, even from the three primary colours.
We have such tints in the beautiful solar spectrum,
but there they blend into one another so gradually that
no eye can count them.
One of the great helps to success is to observe the rule of
being very sparing of both colour and medium when dab-
bing in the sky portion of the picture ; but the painter can
be more lavish with both when he is dealing with foliage,
and any broad masses of light or shade.* Here he can
often use a large camel-hair brush, and can mop in the
colour, only taking care that he does not go over the out-
line which circumscribes the particular portion of the
picture he is working upon. In the case of a mass of foliage,
let him mix up the desired paint on the palette with a
flexible palette knife, which he should always have at hand.
This should be done thoroughly and quickly ; then let him
take up a moderate quantity of this colour in the brush and
mop it on to the surface of the picture. For this class of
work mastic varnish, very much thinned with turpentine,
forms a capital vehicle. The .strength of this mixture may
be one part of mastic to six of turpentine. This medium
keeps liquid long enough for careful manipulation, and yet
it dries quickly in comparison with other media which
might be named.
Photographic transparencies are now produced of such
varied tones that in many cases it will be found advisable
to leave portions of the picture quite uncoloured. With
THE BOOK OF THE LANTERN. 153
chloride plates especially a very wide range of tones can be
obtained, and practically the experienced worker can pro-
duce a picture in any colour, from black, ranging through
different changes of brown, to red ; and even a blue picture
can be produced on that type of plate. It is often prac
ticable to suit the tint to the class of subject. A woodland
scene may be toned a rich brown, for example ; and this
tone, which the picture possesses at the outset, will prove
of great help to the colourist. Many water-colour painters
commence their work by giving the surface upon which
they work a yellow-brown tint, and, when that is dry, they
commence the picture proper. It will be readily seen that,
with a photographic picture toned in the way described, the
slide-colourist will work under much the same conditions.
The object in both cases is to give a general warm tone to
the picture, which cannot be blotted out even by the most
careless and ignorant worker.
It is a good practice to examine the slide in the lantern
as the various stages of the painting progress, taking care
to protect it from dust. For this reason it should, before
being placed on the lantern -stage, be furnished with a
paper mask and a cover-glass ; it may then be slipped in
a mahogany frame kept for the purpose. By this exami-
nation under the light by which it is ultimately to be
shown can we alone judge of its defects. It is now that
the dust, previously invisible, becomes painfully evident.
The beginner will, indeed, be forced to acknowledge that
this is an example of matter in a very wrong place. He
sees up in the sky of his landscape, which he just now
thought would look so very beautiful, what is apparently a
154 THE BOOK OF THE LANTERN.
broomstick ; but careful examination shows that it is only
a little piece of hair about a quarter of an inch in length,
which is magnified into the size of the useful domestic
appliance just mentioned, and, what is more, these little
bits of hair are very difficult to remove. We may per-
haps; lift them with our etching-needle from the paint in
which they are embedded, but in doing so we are pretty
sure to leave scratches behind which are almost as bad as
the hairs. Bits of dust are everywhere, and the only way
in which their intrusion upon our work can be avoided is
to devote a room to this express purpose of slide-painting.
It should be uncarpeted and uncurtained, and should be
swept with tea-leaves, or better still, with damp saw-dust, a
few hours before any painting is attempted. Its table and
only chair should be wiped down with a damp duster, and
the same treatment should be applied to the window ledge,
or any projecting parts of the wood-work which may be
near the painter as he sits at his work. The artist should
put on a linen blouse, which is rigidly kept for this work.
All these precautions may seem unnecessary, but we must
observe them if we want to produce the best possible work.
I have seen slides, otherwise well executed, which were
quite spoiled by dust, and it is one of the aggravations of
the slide-painter's life, that dust always gets into the sky,
where, of course, it is more evident than in any other por-
tion of the picture.
Let the table upon which the operator works be placed
near a window, preferably under a north light. This
table should be wiped over with a damp duster imme-
diately before the work is commenced, and it should be
THE BOOK OF THE LANTERN. 155
covered with a sheet of newspaper, also wiped with the wet
cloth. The easel is put in the front centre of the table ;
on its left-hand side may be placed the colours, while on
the right the palette must be within easy reach, together
with a sheet of tissue-paper folded in four, so as to make a
kind of pad upon which to wipe the brashes. The medium
employed varies with the particular colour which happens
to be in .use, but turpentine forms the basis of all. A
little cup of turpentine should stand close to the palette, in
which the brushes can be washed, previously to being
partially dried by being stroked gently on the pad of
tissue-paper before mentioned.
Supposing that the picture upon which the operator tries
his 'prentice hand is a landscape, the sky will be the portion
of the slide which will first require his attention. Squeeze
out from the Prussian blue tube a little bit of colour about
the size of a grain of wheat, for this tint is so powerful
that a little of it will go a long way. Near it place a little
McGilp. Now dip one of the brushes in the turpentine,
mix it on the palette with the McGilp, and with sufficient
colour to give the strength of tint desired. Now paint
over the sky portion of the picture with bold, even strokes,
from side to side. The brush will leave plenty of markings,
ugty ridges from right to left ; but let these pass for the
present, for we shall remove them in the next stage of
the process. The picture should remain as it is for a
minute or two, so as to give time for the turpentine to
partially evaporate, when we must proceed to the
operation of dabbing. Dabbers are made of different
materials ; sometimes it is recommended to use a piece of
156 THE BOOK OF THE LANTERN.
fine wash-leather, formed into a little ball by cotton wool
inside, tied up like a small pad. I have not found such a
dabber to be satisfactory in practice ; for the leather, how-
ever fine, leaves feathery marks upon the colour, which,
although they are not readily seen on the slide, become
painfully evident when the picture is magnified on the
screen. I myself tried, a short time ago, to make some
special dabbers for this work, which were composed of
gelatine and glycerine moulded in a small cup like an egg-
cap. These dabbers, also, were not as satisfactory as I
could have wished, although I found that they were better
than those of wash-leather. The best dabber which it is
possible to get is the finger. This needs a certain amount
of preparation. The flesh of the finger is covered with a
number of little ridges, which we well know make what
we call finger-marks on anything touched. These ridges
can be obliterated by rubbing the finger with pumice-stone
and water, or by using the pumice-stone soap, which is
sold for the express benefit of much-soiled hands. A
quicker plan is to rub the finger a few times on very fine
glass-paper, when the ridges quickly disappear. It is
obvious that the operation of rubbing down must only be
carried to a slight extent, or "else soreness will result. The
finger makes a far more perfect pad than any artificial con-
trivance because of its exquisite sensibility ; for in using it
we both see and feel the progress of the work.
Commencing at the left-hand top corner, we dab with
the finger rapidly from side to side of the picture ; at first
it will make ugly marks, but the turpentine gradu-
ally evaporates as the work proceeds, and these marks
THE BOOK OF THE LANTERN. 157
blend into one another, until they finally disappear, and we
have before us a flat, even tint of colour. The knack of
laying in a sky cannot be gained without a great deal of
practice ; but the operator may feel assured that when he
has once conquered this initial difficulty half his labour
If we merely want a plain blue sky, and where the
amount of sky is small it is often expedient that this should
be the cas.e, we can consider this portion of our picture
finished with the dabbing ; but if we want to indicate
clouds, this must be done before the colour has commenced
to dry. Here comes in the work of the artist. From what
I have seen exhibited in the shop windows, I conclude that
many slide-painters classify clouds under two general
heads, namely, large masses called "feather-bed clouds,"
and small ones, called " bolster clouds." These are created
by means of a leather stump, moved with a semicircular
motion, by which clouds of either pattern can be wiped
out to order. The student of nature will, however, aim
at something higher than this ; for he will know that no
two clouds, of the thousands he has gazed upon, have ever
been alike. For convenience sake, meteorologists write of
cumulus, cirrus, stratus, and nimbus forms of clouds, but,
in reality, although each term describes a typical form of
vapour, they convey very little information to the mind's
eye. Each form so constantly blends with the other to delight
the eye, that no words can sufficiently describe the vast
variety of cloud beauties presented to us. In attempting
to imitate some of these effects of nature in glass-painting,
I find that a piece of kid wrapped round a pointed stick
158 THE BOOK OF THE LAN1ERN.
is far more serviceable than an ordinary leather stump.
The rough side of the leather should be used as the rub-
bing surface, and, by altering its position on tbe stick,
sometimes letting a soft ragged edge touch the paint where
a fleecy cloud is to be described, and sometimes using the
material tightly stretched over its support where bold
touches are necessary, a great number of different effects
can be secured. The sky being finished, it will be convenient
now to put in any other parts of the picture where blue
or purple is required. The distant hills can be covered
with the sky tint, mingled judiciously with a little crimson -
lake. Water, in which the sky is reflected, will, of course,
be painted in with the sky colour. Shadows generally will
also partake of the purple tint already mentioned. These
are all laid in with the brush, as before indicated, and, time
having been given for tbe partial evaporation of the turpen-
tine, they; must be gently dabbed with the finger. No care
need be taken about transgressing over other portions of
the picture where blue or purple has no business to be.
These can be wiped clean with leather or stump, after the
tints have been satisfactorily laid in.
OX COLOURING PHOTOGRAPHIC TRANSPARENCIES FOR LANTERN
GREAT many subjects can be advantageously
treated as moonlight pictures, and very attractive
they are if well done. In this case, the blue
must be laid on of a much darker hue, and can have
blended with it a little ivory-black. Having decided
upon the best position for the " queen of night," that
place should be lightened by extra hard dabbing, and
any clouds that may be required can be wiped out at
the same time, taking care that their light edges are
nearest to the uncreated moon. The moon must not
be wiped out, but must be picked out, film and all, so
that nothing but bare glass is on the spot covered by it.
To accomplish this, wait until the paint is bone dry, and
attach to the place where the moon is to be a tiny piece of
gummed postage-stamp paper. This should not be bigger
than a small pea, and is merely for the temporary purpose
of holding the leg of a small pair of compasses. I keep a
special pair for this particular work, one leg being ground
160 ' THE BOOK OF THE LANTERN.
so as to form, a cutting edge. Having opened the compass
to the required distance, plant one point on the paper, and
gradually with the other cut through the gelatine film.
The circular disc so marked out can now be quickly picked
away, bit by bit, with the etching-needle. (This needle,
by the way, is merely an ordinary needle, bound to a pen-
holder by waxed thread.) The same instrument can be
used afterwards for picking out effective lights in the fore-
ground ; but the great fear is that the beginner should
abuse the power thus put into his hands. The touches
should be of the most minute description, and the operator
should constantly remember that his work, with all its
faults, has to be magnified to a very great extent.
I need hardly point out that a most effective change can
be made by showing a landscape, first coloured as a day-
light picture, and then dissolving it into the same view by
moonlight. This change requires a double dissolving-view
lantern, the daylight picture being placed in one lantern,
while the moonlight picture is placed in the other, care
being taken that both pictures register; that is to say,
occupy exactly the same position on the sheet upon which
the images are projected.
But let the beginner not attempt sunsets of the gorgeous
order, after the manner of G. M. W. Turner (deceased),
until great practice has taught him the different character-
istics of his colours. I do not here allude to their tone
character, but to the different ways they behave, mechani-
cally, when applied to the slippery surface of the picture,
and the different media required to coax them into lying
flat. He may think that, because he knows how to produce
THE BOOK OF THE LANTERN. 161
a good even sky-blue tint, he has only to try the same pro-
cedure with his yellows and reds to produce all kinds of
brilliant, ethereal, striped-petticoat effects. But, on trying
these colours, he will soon find out his mistake, and will
also find that he must add varnish to them before he can
work with them at all. Moreover, they seem to be espe-
cially prone to attract any little unconsidered trifles in the
way of dust which may be seeking rest.
I was so impressed with these difficulties with regard to
sunset skies, when first I began glass painting, that [ sought
for another means altogether for gaining what I wished.
I was attracted by the brilliant hues of the aniline, or coal-
tar colours, and at once endeavoured to enlist them into my
service. As others may be tempted to work in the same
groove, I may at once state why, after patient trial, I dis-
carded them. Most of these colours can be readily dissolved
in alcohol, and, therefore, it is not difficult to make
coloured varnishes with them. But when I tried to paint
my gelatine picture with the splendid tints, I found it next
to impossible to confine them within the boundaries of any
outlines whatever. They would flow over the edges on
their own account, do what I might. The fact is that these
aniline colours have a kind of greedy affinity for gelatine,
and there seem to be no means of controlling their advance
when once they come into contact with it. By flooding
an entire picture with a yellow or red varnish, I was able
to gain (sometimes) some wonderful effects. But the action
of the dye upon the gelatine was of too uncertain a nature
to tempt me to adopt that method of working as a perma-
nent resource. Lastly, aniline colours are fugitive.
162 THE BOOK OF THE LANTERN.
Hitherto I have regarded the picture as possessing a
plain glass surface to represent the sky, and this will be
found to be the case with most photographic slides. But
we all know that a plain white sky in a photograph is, from
an artistic point of view, an abomination. By the simple
process of colouring we get over the difficulty ; still, if we
can produce upon a photographic transparency natural
clouds either existing in the original negative by the virtue
of a properly-constructed shutter, which will only give a
fraction of the normal exposure to the sky, or by a system
of printing-in from a separate negative in a way that need
not be described here, it will be a great artistic gain. In
colouring such a sky the painter has a great advantage, for
irregularities in laying on the colour, which would other-
wise be distinctly visible, are hidden by the details of the
clouds in the picture.
In colouring such a sky we may commence, as usual, by
dabbing on the blue in the spaces which represent rifts
between the clouds, and we can then add tender tints made
up by mingling such colours as crimson lake, and the
various yellows at our disposal, and we can also add to the
richness of the general effect by putting in different tones
of lavender, mauve, and purple, made up with crimson lake,
the madders, and blue. These colours, after the blue has
been dabbed on, can best be painted in with the brush,
using as a medium Canada balsam in turpentine. This is
a good, quick-drying medium, and it has the advantage of
being so pale in colour that it will not affect the most deli-
Before proceeding farther with the work, the picture
THE BOOK OF THE LANTERN. 163
should be dried by heat, and there are many means of
doing this. An oven, not too hot, will do what is neces-
sary, but it is uncertain, for the heat may rise to such a
pitch that picture, gelatine, and all will curl off the glass.
A tin biscuit canister, divided into grooves, and placed
(dutch oven fashion) in front of a good clear fire is better ;
but the best plan that I have tried is the following : place
the glasses to be dried upon a flat iron plate above a gas
stove, the heat of which can be regulated. Upon the top
of the plate put a frame of wood, covered with fine muslin,
to keep off the dust. About twenty minutes of such treat-
ment will make the layer of paint on the glass so hard
that it can be worked upon with other colours, or sub-
mitted to the moonlight operation as already described. It
is during the operation of laying in the sky, &c., which may
be comprehended under the term " first painting," and the
subsequent drying, that access of dust must be carefully
Lantern slides, by Whatever photographic process they
may have been produced, will stand a great deal of heat,
and they can be made hotter than the hand can con-
venie,ntly bear with impunity. This heat may be con-
tinued for about half an hour, and it will be found that
it has a kind of japanning effect upon the oil colours
employed ; indeed, the colours are by this means made so
hard that it is difficult, if not impossible, to remove them
afterwards without at the same time destroying the photo-
graphic image beneath the pigment.
After the sky has been dried in the manner described, it
can easily be deepened, if found necessary, by the &pplica-
164 THE BOOK OF THE LANTERN.
tion of a little more paint, which need not be applied with
a brush, but can be simply dabbed on with the finger.
Some very good effects are often possible by this second
painting, especially when the sky is. deepened, in the
manner described, at its upper part or zenith ; such a
deepening, it will be readily seen, being in strict accordance
with the sky of nature.
A blue sky with white clouds formed by the simple
operation of wiping out the colour, and leaving the clear
gelatine, is by far the easiest kind of sky to produce. It can
be modified in various ways by working other colours upon
it near the horizon, such as red or black, most sparingly
bestowed, or the zenith tint can be strengthened after the
slide has been dried. A most effective sky is that which I
may call the ordinary summer twilight sky, that is to say,^
the deep blue at the zenith, fading gradually to a lighter tint
until it merges into bright yellow or orange at the horizon.
Such a sky is not difficult to produce. The best way will
be to commence at the horizon by dabbing, without the
use of the brush, Italian pink on to the glass ; a very little
colour being applied to the finger, with the addition of the
merest trace of medium, such as Canada balsam, in turpen-
tine. This must be diligently dabbed upon the glass until
its stickiness almost disappears, and its upper margin is
left without any hard lines. Then the finger should be
washed in the cup of turpentine which the painter should
always have at his elbow, and the blue may be applied to the
upper part of the picture in the ordinary way, and dabbed
down until it almost touches the yellow which has been
previously laid on. Once more wash and dry the dabbing
THE BOOK OF THE LANTERN. 165
finger, and then use it, without any fresh application of
paint, to merge the two colours into one. In this way
it will be found, after a little practice, that a good junction
can be made, and that one colour will exhibit a regular
gradation into the other. If this work is well done, the
effect will be found to be a most pleasing one,, and should
not be meddled with by the addition of clouds.
Our painting has now progressed to a certain stage. The
sky has been laid in, the clouds have been wdped out, and
the shadows have received a delicate purple tint. The
whole has been submitted to a baking operation, by which
the attached colours are made so hard and firm, that it
would be difficult to remove them without destroy ing at the
same time the gelatine film upon which they are superposed.
We now place this unfinished sketch again upon the glass
easel, and will endeavour to turn it into a finished picture.
It is at present what Mr. Whistler would call " an arrange-
ment in purple and blue." We will endeavour, by working
over these tints where required, and by adding others, to
produce a general harmony of effect, as nearly approaching
to nature as possible.
Any one possessing artistic feeling, and no one without
that faculty will make a really good slide-painter, although he
may easily come up to a common standard, will, on first
looking at the subject for colouring, make up his mind as
to the way in which he means to treat it. He will arrange
to have a cloud mass in one place, possibly to relieve a
church steeple or other high building, or a bright horizon
where, possibly, lights are to be seen through tangled
masses of foliage ; or in other ways he will have in his
166 THE BOOK OF THE LANTERN.
mind a definite programme to follow out, and will do his
best to achieve it, and will do so with more or less
success. But, through all, he must bear in mind that his
picture will eventually be highly magnified, and that the
least blemish will be magnified too. In no art, perhaps,
can a man learn more by repeated failures (failures
which should be, from time to time, submitted to the
searching light of the lantern) than he can in this art
The worker must constantly remember that the effective-
ness of his picture is dependent far more upon contrast
than upon the tone of any particular tint. Without con-
trast his colours will be meaningless and poor, although,
individually they may present brilliant hues. The rule
governing contrast of painters' colours, i.e., colours which
are complimentary to one another, is most simple. Here
it is in a nutshell. The three primary colours are red, blue,
and yellow.* Any two of these mixed together form a
secondary colour which is complimentary to the remaining
primary. For example : Red and blue mingled form
purple. What better contrast to purple can there be than
yellow, its complimentary, being the primary which is
left out of the combination ? * Again, blue and yellow form
green, and green is complimentary to red. Once more,
yellow and red form orange, the complimentary of blue.
I have no hesitation in saying that a man possessing this
little bit of elementary knowledge is far more likely to
* This is not correct for coloured light, but answers for painters'
THE BOOK OF THE LANTERN. 167
produce an effective picture with three colours than can
one ignorant of it, although he may have the run of all
the artists' colour-shops in the kingdom. He can never go
far wrong if he will, so far as the subject will allow, place
green against red, orange near blue, and yellow in conjunc-
tion with purple. A subject, such as an Oriental street-
scene or bazaar, where such combinations can be made
without stint, has a most gorgeous effect when projected
upon a screen. Each of these colours can at the same time
be mingled to give an endless range of tints, in fact, all
the colours of the rainbow. And now let me give a few
hints as to finishing colours and combinations useful for
special purposes, together with the best media with which
to mix them. In these finishing colours the dabber, except
in extreme cases, must be relinquished, and the brush
(camel hair and sable) alone employed.
Skies and Clouds. Prussian blue (some prefer Chinese
blue), rose madder, purple madder, Italian pink. The blue
to be laid on as already described, using as a medium
McGilp and turpentine. In laying on after tints a small
quantity of copal varnish should be added.
Water always reflects the colours above it. If the water
be very still, the effect of surface may be given to it by
drawing gently across it a dry (mop) brush, such as gilders
use. In brooks and running streams, lights may be picked
out while the colour is wet, with a pointed stick, or when
dry with the etching-needle. In representing rough sea,
we must remember that such water not only reflects the
colour of the sky above it, but shows also its local colour.
It may first be painted over with the sky colour, and, after
168 THE BOOK OF THE LANTERX.
baking and drying, this can be worked upon with various
shades of yellow, blue, brown madder, and indigo ; medium
Canada balsam varnish, McGilp, and turpentine.
Boats and Shipping. Black, raw sienna, Vandyke
brown, burnt sienna, Chinese orange, indigo, indeed,
nearly all the colours available. Medium, same as last.
Foliage. For foliage we are limited for our greens to a
mixture of Prussian blue and the various yellows, namely,
Italian pink, raw sienna, and brown pink. But these will
give endless variety of tones, particularly when aided by
other colours. Here are a few examples :
Blue, Italian pink, and burnt sienna.
Italian pink, Vandyke brown, and indigo.
Italian pink and brown madder.
Brown madder, Italian pink, and indigo.
By adding Chinese orange to any of these, autumnal
effects are readily obtained. Media, Canada balsam var-
nish ; and for the darker colours, gold size. N.B. These
various combinations should be made up on the palette,
as required, with the help of the palette knife.
Foreground. It is here that the artist can employ all
the treasures of his palette. Let him remember that any
particular colour can be easily modified by glazing another
colour over it. This is done after the first colour is dry
by mixing a second tint, which may be applied above it.
The medium for this varnish will vary with the glazing
colour employed. Canada balsam will do for most, but
where reds are used, which are slow driers, the medium
should be gold size.
Let the painter ever remember that force of colour can-
THE BOOK OF THE LANTERN. 169
not be obtained by piling on masses of pigment, which will
naturally serve to obscure the details of the photograph
upon which such pigment is placed ; but this force of
colour can be easily produced by judicious contrast of differ-
ent tints. As I have before observed, the student must
make himself master of the art of colouring, if possible,
before he commences its practice. Some years ago there
was published an excellent series of little books, costing
only a few pence each, giving chromo-lithographic examples
of various simple studies in water-colour painting by
Callow and other artists, under the title of " Vere Foster's
Drawing Books." These books, I believe, are still to be
had, at least, I hope so, for they are full of merit, and
give more valuable instruction than many works of far
more pretension. They give specimens of water-colour
sketches, unfinished and finished, side by side. Perhaps
the former are the more valuable for our present purposes,
for they exhibit merely broad masses of colour, and show
how one tint can be made to contrast with another. It
will be seen in some of these pictures that a blue sky is
contrasted with orange yellows in the landscape beneath
and how, on the other hand, a yellow sky can be rendered
at once effective by purple hills upon which it seems to
When the picture is entirely finished, it may be once
more submitted to the baking operation, taking care that
the heat never rises to blistering point, or all the labour
spent on the slide will be thrown away. The picture may
now again be placed on the easel, and if the artist has
sufficient reliance upon his power of knowing when to stop
THE BOOK OF THE LANTERN.
he may with advantage take up the etching-needle ; some-
times a single touch of this magic wand will much improve
a picture. In forest scenery, for instance, a light on a
trunk, or on a protruding branch, will make the one or the
other to stand out almost stereoscopically. Now and then
too a little spot or two may be picked out of the foliage
itself. But not in the manner I lately saw in an exhibited
slide, where curly lines, after the drawing-master style of
former days, were made to describe the edges of the trees
in every direction. This was actually perpetrated upon a
good photograph, and represents the worst instance of
" painting the lily " which I have had the misfortune to
DESCRIPTION OF VARIOUS EXPERIMENTS, CHEMICAL, ELECTRICAL,
ETC., FOR CLASS INSTRUCTION, WHICH ARE POSSIBLE WITH
|OB different experiments, various forms of slides
must be employed. The galvanometer slide,
shown at fig. 45, is an extremely useful
one for demonstrations in electricity and magnetism.
I need hardly mention that such a slide consists of
a magnetised needle, which is surrounded by a coil
of fine wire. This coil is flattened, and there is just
space enough between its convolutions for the needle
to move from side to side. It is supported on
172 THE BOOK OF THE LANTERN.
a central pin, which is shown by the screw slit in the cut.
A pane of glass of a semicircular shape forms a back-
ground for the needle ; and this glass can either be left
plain, as in the illustration, or it can have drawn upon it a
scale. The slide figured is without the arrangement just
mentioned, and it is one that I have employed for a special
purpose. I have used it as a means of demonstrating the
action of the needle telegraphic instrument ; and it will
be noticed that two little buttons are fastened to the
glass in order to prevent the needle making too wide an
It may be mentioned here for the benefit of those who
are unused to electrical instruments, that a galvanometer
furnishes the means of detecting the existence of an elec-
tric current. In its higher forms it is so sensitive that
a current, generated by touching two dissimilar metals
with the fingers and excited by the natural warmth of the
hand, can, by a galvanometer, be made evident to the eye.
The most simple form of galvanometer can be readily
made from one of those little charm compasses which are
sold at the opticians' for about Is. each. Take such a
compass, and bind it across with several layers of fine silk-
covered copper wire. Place it in such a position that the
wire coil lies parallel with the needle, which will, of course,
be north and south ; now join the ends of the wire to
any form of electric battery, and the needle will imme-
diately swing round and take an east and west direction.
By changing the position of the wires with regard to the
poles of the battery, it will be noticed that the needle is
deflected in the opposite direction. These phenomena
THE BOOK OF THE LANTERN.
form the basis of the single needle electric telegraph, and
it is to demonstrate the powers of that telegraph that the
lantern galvanometer, which
is here figured, has been
devised. It will be noticed
that on its right-hand side it
is furnished with two ter-
minals. These are connected
with the ends of the coil
wire, and provide a means of
readily joining the instrument
up to the battery, placed in
any position outside the lantern ; but in practice it will
be found advisable to also place in connexion with this
slide and its battery a little piece of apparatus which may
be called a "current reverser," which can easily be made
at home. It is shown in fig. 46. It consists of two
little treadles formed out of brass. This brass, it may
be mentioned, should be of the hard-rolled kind, such as
is used for springs.
Each of these little treadles is fastened down to a maho-
gany board, which forms the base of the instrument, and
each one is in connexion with a terminal screw, which is
indicated in the cut by a round dot. Across the other end
of the treadles is a raised bar of brass, against which they
spring up and touch when in their normal condition ; but
when either of them is pressed down, it touches a piece of
brass wire which is let into the top of the mahogany board
This wire, as well as the piece of brass just mentioned,
174 THE BOOK OF THE LANTERN.
is connected with its own terminal ; these two latter ter-
minals in the cut being lettered bb, and signifying that
they should be joined up to the battery employed. The
other two, which are lettered gg, are fastened to the
terminals on the galvanometer slides.
In practice it is best for the current reverser to be placed
on the lecturer's desk, at some distance from the lantern,
while the galvanometer slide is joined up by means of tem-
porary wire connexions. The lecturer then has the power
of reversing the current by touching with his finger either
of the two treadles, and he can demonstrate in the most
perfect manner how the different letters in the tele-
graphic alphabet are made up of movements of the needle
to the right or left, as the case may be. He can also point
out that the " dots " and " dashes " of the Morse system
correspond with these right and left hand movements of
the magnetic needle.
In the old days of the Polytechnic Institution in Regent
Street, which was the resort of so many delighted schoolboys
and girls, there were several experiments performed with the
lantern which, so far as I know, have not been repeated
elsewhere. One of the most curious was the movements of
the legs of a frog. This is rather a difficult experiment to
perform, but when well done, is highly effective on the
At the Polytechnic the frog's legs covered the large
screen, and were thus magnified to about 26 feet. The legs
were hung to a special form of slide, and the nerves and
muscles of the dead frog were touched with metallic wires,
when they immediately kicked out in the most startling
THE BOOK OF THE LANTERN. 175
manner. The importance of this experiment, as a demon-
stration, will be acknowledged when it is remembered that
this movement of a frog's legs, accidentally brought about
by Galvani, laid the foundation of our present knowledge of
current Electricity or Galvanism, as it used to be called,
after that first experimenter.
Another most effective experiment was shown in con-
nection with a lecture upon the Suez Canal by Professor
Pepper. After exhibiting a number of experiments upon
sand, and showing that it always fell at a certain angle,
and exerted lateral instead of perpendicular pressure,
an image of an ordinary hour-glass was cast upon the
screen. This sand-glass was supported in a frame, and its
sides were flattened so that it could fit the lantern stage. It
had rather an amusing appearance, because like all instru-
ments placed in the lantern, the image was inverted, and
the sand therefore appeared to flow upward instead of
downward. A curious fact, too, was noticed when this
familiar instrument was magnified to such an enormous ex-
tent, each particle of sand was seen to strike a blow upon
the top of the cone above, and the force from that blow
passed from the point of the inverted cone to its base, and
formed a peculiar wave -like figure in its passage.
I have never seen this experiment repeated elsewhere,
but it is one that should not be forgotten.
Among the experiments which can be performed by
means of a lantern, and better performed, so far as an
audience is concerned, than by any other means, are
those relating to cohesion figures. Professor Tomlinson
was the first to give much attention to these interesting
176 THE BOOK OF THE LANTERN.
figures, and he made many experiments in this direction.
He found that almost all the common oils and fats give
natural diagrams by which they can be identified ; and
further, that these figures will vary, according to the length
of time for which the oil has been exposed to the air. To
get some idea of the nature of these beautiful figures, a
drop of pure sperm oil may be allowed to fall on the surface
of a pan of water. It will be seen in a few seconds that
the film of oil will break up into a number of little open-
ings, and that it will exhibit a pattern of great beauty.
Rape oil, Lucca oil, and some others, give patterns of en-
tirely different designs ; some of them very much resembling
beautiful crochet- work. In order to show these patterns
in the lantern, we have two or three different methods of
going to work. We can exhibit these cohesion figures, for
instance, by the simple aid of two pieces of clear glass.
Between two such plates put a little vaseline, which in
order to increase the effect on the screen may be coloured
red with alkanet root. The plates are pressed together, with
the vaseline between them, and are then secured by a ring of
india-rubber at each end. They are then put into the lan-
tern, and while standing upon the lantern stage the blade
of a knife is inserted between the two glasses and gradually
turned so that they are slightly separated. The effect
upon the screen is very beautiful, the disc appearing to be
covered with arborescent figures. This experiment may be
repeated more than once, but the vaseline will require
renewal after a time. Another mode, and perhaps a better
one, of showing the same phenomena, is by means of the
vertical attachment to the lantern. In this case the
THE BOOK OF THE LANTERN. 177
lantern slide must take the form of a shallow box, having
a glass bottom. Such a box can easily be made by fit-
ting a piece of thin glass, say, 3J inches square, into
a frame of wood half an inch in height, and cementing
the glass in a groove with marine glue. The glass
cell so provided should be placed in a horizontal
position upon the stage, and be filled with water. Dif-
ferent oils can then be dropped on to the surface of the
water, and the characteristic cohesion figures due to each
will be thrown upon the screen. If this latter mode of
showing the phenomena be chosen, it is obvious that a
different glass cell must be used for each oil exhibited,
and I think that it would be quite possible to produce
lantern slides direct from these oily cohesion figures ;
although I have not experimented in this direction myself.
The principle employed would be that of " Lithography."
The oily figures might be transferred to a piece of glass
direct from the surface of the water. Those figures could
be darkened to any extent by employing a greasy printing
ink, taking care to wet the glass so as to repel the ink ;
but this is a matter into which,! cannot now afford space
to enter, and I merely allude to it as a field for profitable
Many pieces of apparatus have been devised for the
lantern, which exhibit the principle of what is known as
kt persistence of vision." In order that we may thoroughly
understand in what this principle consists, I may men-
tion that the human eye possesses a peculiar property
which is highly convenient to its proprietor. What is
meant by " persistence " is that the retina has the power
178 THE BOOK OF THE LANTERN.
of retaining the image of anything seen for at least one-
eighth part of a second after the eye ceases to see that
As an example of this, let me remind my readers, that
although in the ordinary course of things, we are con-
tinually "winking," an operation which is necessary to
lubricate the eyeball, we are quite insensible of the cir-
cumstance that for the time occupied in doing so, we are
placed in absolute darkness. Although the eyelids are
closed and the light is shut out, we have no perception of
darkness, simply because of this curious property possessed
by the retina of retaining the image of the object last seen,
for at least the eighth part of a second. It is for this
reason, I may also point out in passing, that so-called
instantaneous photographs of moving objects, such as a
" trotting horse," &c., appear to us to exhibit such very
unnatural attitudes. As a matter of fact the photographic
camera records movements which the human eye, on account
of this "persistence of vision," cannot appreciate. It is
evident that if this doctrine be true, the eye cannot appre-
ciate a movement which takes place in less time than the
eighth part of a second, and it is because the photographic
lens can grasp and record the movements which take place
in a mere fraction of that time, that the attitudes it depicts
appear to us so highly unnatural. The human eye has
never seen such attitudes, and never will see them.
Perhaps the simplest illustration of " persistence of
vision " is afforded by a burnt stick with a red hot end,
which is turned rapidly round in front of the observer ;
<fco that observer the red spot of light looks like a con-
THE BOOK OF THE LANTERN. 179
tinuous ring of fire, but we know well enough that it is
simply a spark. It is the rapid movement helped by this
" persistence " of the retina, that causes the spot of light to
appear to us as a continuous circle. So it is that heavy
rain drops, which we know very well are independent
globules of water, appear to be like streaks falling from
the sky, and like streaks artists invariably depict them.
And rightly so, too, for we do not wish artists to bring
before us representations of things as the eye cannot see
them, but of objects as they appear to us under ordinary
conditions. For this reason the claim which has been made
in some quarters, that the unusual attitudes depicted by
instantaneous photography, should be a help to artists in
their delineation of animal movement, appears to be ex-
tremely nonsensical. Such attitudes may certainly be
studied by artists, as a means of showing how the various
movements are brought about, just as he would study the
skeleton of a man, in order to get a better notion of the
outward form of the body; but both should be kept as
studies, and certainly not introduced into finished works.
The kaleidotrope consists of a disc of perforated cardboard.
It is supported on a spring of wire in such a manner that it
can be rapidly turned round by the finger as the frame in
which it is contained stands upon the lantern stage. The
other end of the spring is cemented to a plate of glass so
that the light can easily travel through the perforations in
the disc and be rendered evident on the lantern screen.
As this card is struck with the finger so as to cause it to
move and vibrate on its spring in different directions,
the spots of light on the screen by their movement assume
180 THE BOOK OF THE LANTERN.
a great variety of curves. It will be thus seen that this
instrument simply gives a variation of the burnt-stick
experiment already alluded to.
Mr. Beale, of Greenwich, has invented a most ingenious
and amusing apparatus for the lantern which also depends
upon " persistence of vision." This is called the choreuto-
scope, and is made in two different forms. In its more elabo-
rate shape it consists of a circular plate having upon it figures
drawn upon glass, and so arranged with their limbs in
different attitudes, zoetrope fashion, that when one figure
is rapidly changed for the other, the image seems to be in
actual movement. The contrivance is so arranged that
before the figure actually changes a little screen obscures
it for the moment, so that the movement of the disc is not
apparent upon the sheet. Mr. Beale has of late years
simplified this instrument. In this case the figures are
painted upon a slip of glass about seven inches in length,
and by means of a special form of slide they are rapidly
brought in front of the lens in the manner just described.
The most effective set of figures of any is a skeleton, the
reason being that it consists only of white on black.
Such figures can therefore be cut out, stencil fashion, in
a sheet of thin copper-foil ; the openings in this plate per-
mitting a far larger amount of light to reach the screen
than if the figures were drawn upon glass.
Another far more perfect and elaborate device for illus-
trating the phenomena connected with persistence of
vision is an instrument called by the somewhat ponderous
title, the Astrometeoroscope. The inventor of this clever
piece of apparatus was the Hungarian mechanician,
THE BOOK OF THE LANTERN. 181
S. Pichler, who designed various other ingenious contriv-
ances. He was very jealous about this astrometeoroscope,
and the onlj one made was at the Polytechnic Institution,
where it was carefully kept under lock and key, except
when in actual use. When the apparatus of the institution
came to the hammer, I remember that there was some
little excitement when the astrometeoroscope was put up
for sale. Opticians and others would have been glad to
get hold of it, so as to have multiplied it for sale. This led
to a brisk competition, ending with Mr. Pichler giving an
extravagant price for his own bantling. And in that way
the secret remains in the hands of a few only, and perhaps
it would be unkind to divulge it. But, at any rate, I
cannot do much harm by giving a general idea of the out-
ward appearance of the instrument and its capabilities.
The astrometeoroscope consists of a narrow box thirteen
inches in length, and of such a width that at one end it
will fit the stage of the lantern. At this end it has the
usual three-inch disc opening, which is occupied by two
plates of metal which are scored across obliquely with slits
and which are superposed one. on the other, so that the
slits on each cross one another diagonally. Now it
is clear that the only places where light can pierce
these plates of metal so as to make itself evident on
the screen is in those places where the slits on the plates
intersect one another. The effect on the screen, therefore,
whilst the instrument is quiescent, is a series of dots of
light all over the screen, but at regular distances from one
another. By very ingenious mechanism the two plates are
caused to move to and fro in contrary directions, and the
182 THE BOOK OF THE LANTERX.
speed of either can be varied at will by the operator. The
effect upon the screen is most curious, for it seems to be
covered with a lacework of geometrical patterns which
constantly change their form.
A very favourite experiment with the lantern, but one
which it is by no means easy to perform, is the decomposi-
tion of light by means of a prism. For the most perfect
effects the electric light is necessary, but as this is beyond
the reach of most of us, at any rate, for the present, we
must be content with what can be done with the ordinary
limelight. The simplest way of showing the spectrum
with the lantern is to remove the objective and to place in
the lantern stage a card with a slit in it, as
shown in the cut (fig. 47). This slit should be
about an inch in length, and not more than
one-twentieth of an inch in breadth. The card
should be placed on the stage of the lantern in a
IIG. 47. h or i z ontal position and focussed upon the screen
in front. A prism is then brought into the path of the
slice of light thus formed,
and it will be so far bent
aside as to exhibit the.
colours of the spectrum on
the ceiling of the room
(fig. 48). FIG. 48.
The prism will require a little turning about before this
result is arrived at. But at the best this method of show-
ing the spectrum is but a makeshift one ; it presents,
however, an easy method of demonstrating the decom-
position of white light. A preferable mode is to use a
THE BOOK OF THE LANTERX. 183
bisulphide of carbon prism. This takes the form of a
stoppered bottle with two sides ground away and filled in
with plates of glass, which are cemented to the re-
mainder of the bottle. In this way the wedge form
of the prism is secured. The bottle is then filled with
bi-sulphide of carbon, and such bottles, ready charged, can
be obtained at the opticians'. A great objection to them
is their liability to breakage, for bi-sulphide of carbon,
beyond being a most inflammable compound, has a most
disagreeable and pungent odour.
In using a prism of this description, it is kept upright
and supported in front of the lantern. The slit in the card
must in this case be vertical, instead of horizontal, and the
lantern must be placed at such an angle with the sheet
that when the spectrum is rendered visible it appears in a
central place on the sheet.
There are several means available for showing on the
lecture-table that the various colours of the spectrum will,
when combined, once more form white light. Thus we
may place in the path of the coloured beam a double con-
vex lens, which will at once bring the scattered rays to a
focus, and will form a disc of white light. We can also
recompose light by collecting the coloured rays by means
of a concave mirror, when a card held in the focus of the
mirror will exhibit a brilliant spot of light free from
colour. Another method is to use two prisms placed
against one another, thus Ay> when one will neutralise
the effect of the other, and the emergent beam will be
white. Yet another way of recomposing light is to use a
number (generally seven) of plain mirrors, which are so
184 THE BOOK OF THE LANTERN.
placed upon a stand that they can each be turned in any
required direction. The spectrum is allowed to fall upon
this system of mirrors, and each one is so turned upon its
axis that the particular colour which it reflects is thrown
upon one spot. The collective images of the various
colours then appears as a white disc.
The methods thus detailed are all good, but cannot
readily be applied to the lantern. A way of demonstrating
the recomposition of light with that instrument has
recently been published in America, by Mr. G. M. Hop-
kins, and the following remarks are borrowed from him.
After detailing the various known methods of recomposing
light, he says : "Besides these methods, the spectrum has
been recombined by whirling or rocking a prism ; the move-
ment of the spectrum being so rapid as to be beyond the
power of the eye to follow, the retina receiving the impres-
sion merely as a band of white light, the colours being
united by the superposing of the rapidly succeeding
impressions, which are retained for an appreciable length
of time. The engraving shows a device to be used in
place of the ordinary rocking prism. It is perfectly
simple, and involves no mechanism. It consists of an
inexpensive prism, having attached to a knob on either
end a rubber band. In the present ease the bands are
attached by making in each a short slit, and insert-
ing the knobs of the prism in the slit. The rubber
bands can be held by inserting two fingers in each and
drawing them taut. The prism can then be held in a
beam of sunlight, and with one finger the prism is given
an oscillating motion. The band of light thus elongated
THE BOOK OF THE LANTERN. 185
will have prismatic colours at opposite ends, but the entire
central portion will be white. To show that the colours of
the spectrum pass over every portion of the path of the
light, as indicated by the band, the prism may be rocked
"By inserting four screw hooks in a vertical support, and
stretching the bands over the hooks, the prism is adapted
for use with a lantern. The light emerging from the
lantern must pass through a narrow slit to secure a per-
fect spectrum, and between the screen and the prism
should be placed another screen with an oblong aper-
ture, which will allow all of the band of light to appear
upon the screen, with the exception of the coloured
extremities. With the prism supported in this way, it is
an easy matter to turn it slowly back and forth, showing
on the screen the moving spectrum, which, with the more
rapid movement, produces the pure white band of light."
The recomposition of light can be well shown in the
way just described ; but perhaps a more ready and effec-
tive, if not quite so scientific, a method is to use a coloured
disc, fitted as a lantern-slide, with a revolving arrangement
similar to that used for chromotropes.
Newton's disc, as it is called, consists of all the colours
of the spectrum, painted in transparent colours, in their
right proportions, upon a revolving disc, and as this
disc is rapidly turned in the lantern, the various
colours projected upon the screen in front mingle together
on the retina, and the general effect is that of white
light. It may happen that a lecturer may touch
upon the study of spectra without wishing to burden him-
186 THE BOOK OF THE LANTERN.
self with the necessary apparatus for showing them upon
the screen. Or he may be employing a large lantern to
illustrate other parts of his lecture, which would be quite
unsuitable, or, at any rate, would have to be re-arranged
before a single spectrum experiment could be shown.
Feeling this want myself, I devised a plan for showing
spectra diagramatically with an ordinary biunial lantern.
(It will presently be seen that a double lantern is a neces-
sity for this particular manner of working), and I have
found the method adopted to answer admirably. A special
set of slides is required, but these are not at all difficult
to make. They must be home-made, for they are not to
be bought at present, although one well-known optician
was so pleased with the idea when I described it to him,
that he expressed his intention of manufacturing slides of
my pattern. The first of the set is a photographic slide
showing Newton's well-known experiment with a prism,
traversed by a beam of light admitted through an aperture
in the shutter of a darkened room. The next slide is a
simple-coloured band, or continuous spectrum. This is at
length replaced by a similar band, no longer continuous, but
crossed by the principal Frauenhofer lines, which are duly
marked above with their own distinguishing letters. Such
a spectrum can be copied from any work on optics, and
drawn and coloured on ground-glass, as explained in
another part of this book. We must now prepare a set of
slides to serve as " effects " for this last spectrum slide,
and which will consist of simple bright lines. The most
simple of these would be that due to the metal sodium,
which would consist of a double yellow line, to agree in
THE BOOK OF THE LANTERN. 187
position with that marked D in the spectrum-slide. To
produce such a slide it is only necessary to paste over a
piece of glass a piece of stout black paper, and to cut
out with a sharp knife, when the paper is dry, the line
required. A little varnish colour over the cut-out place will
complete the slide. In using this " effect " the audience
should have explained to them the theory which seeks to
explain the reversal of the lines in the spectrum, and at
the right moment the spectrum-slide is so far darkened
by moving the lantern-dissolver, that the clear sodium
line shines out brightly over the spot occupied before by
the dark D line. I need hardly say that the two slides
must be in perfect register, or the effect will be spoiled.
The spectrum-slide can now be once more exhibited, and
another bright line example placed in the other lantern
ready to be made visible as the sodium one was just
now. The spectra of all the different metals can thus be
illustrated by the bright lines which they afford. The
method may perhaps be considered rough, but the effect is
startling, and few among a general audience are able at
once to realise how it is done.
Double refraction can be shown on the screen in the
following manner : A card with a simple perforation about
one-eighth of an inch in diameter is inserted on the lantern-
stage, and its image is focussed on the screen. A crystal
of Iceland spa is then placed between this card and the
objective lens, and two spots of light will become apparent
upon the sheet.
It may be mentioned here that in all experiments where
colour is required it is better, if possible, to use coloured
188 THE BOOK OF THE LANTERN.
gelatine than any other medium. Ordinary coloured glass
absorbs so much light that it is of very little use in lantern
experiments ; and if the operator will try the effect of
coloured glass and coloured gelatine side by side he will
be surprised at the advantage gained from using the latter.
There is one objection to gelatine, and that is, if a very
powerful limelight be used it is apt to be affected by the
heat ; but this is only the case if the medium in question
is kept for a protracted time on the lantern-stage.
A large number of experiments illustrating the theory
of colour and the laws of complimentary tints can be
arranged by means of pieces of cardboard with different
shaped orifices cut in them, filled in with coloured gelatine.
Such examples will easily suggest themselves to any
operator with the assistance of a reliable book on the
theory of colour. I may mention here a simple arrange-
ment for showing the way in which the retina becomes
fatigued by looking at an object for some time.
It consists of a card with
two semicircular openings,
divided by a horizontal bar
(see fig. 49). Over one open-
ing, say the lower one, a
FIG. 49. piece of card is placed so
that the image of the upper one alone is projected upon
the screen. After looking at this image for some time,
the card obscuring the lower opening is suddenly with-
drawn, and it is then strange to note how one opening
appears to be far duller than the other, although both are
in reality equally illuminated.
THE BOOK OF THE LANTERN. 189
Another method which illustrates the tiring of the
retina, and which also demonstrates the law of compli-
mentary colours, can be shown thus :
A card having a round opening in the centre, filled in
with red gelatine, is placed on the lantern stage, and its
image allowed to remain upon the sheet for some little
time, the attention of the spectator being concentrated
upon it. The gelatine is suddenly removed, when al-
though the image of the opening is of course perfectly
Avhite, it appears to be green, because the retina is tired
by its exposure to the red, and can only for a time appre-
ciate the remaining colours of the spectrum, which mingled
form green ; of course, any primary colour can be chosen
for the experiment, and its complimentary tint will be
made manifest. This is but a variation of that advertise-
ment which has been so common in our streets for some
time, where the onlooker is invited to gaze upon cer-
tain colours for so many seconds, when the image of the
coloured letters looked at will appear, but in their com-
plimentary tint, upon the blank space above.
For experimental work with the lantern, a special form
of instrument should be used. I have lately seen a form
which I think found its origin in Germany ; in which the
objective is so arranged on a sliding base board, that a
clear space of some inches is left between it and the lantern
condensers ; while a little table between the two serves to
support any object whose shadow it is desirable to throw
upon the screen. If we are content with the mineral oil
lantern, and with such a lantern a great many experiments
can be shown, at any rate in a small room, we can ar-
THE BOOK OF THE LANTERN.
range matters in a very simple manner. Let the lantern
stand on a base board, and let the objective be supported
upon a sliding piece in front of that board. Cut away the
tin nozzle upon which the objective fits in the ordinary
way, so that any object can easily be brought between
condenser and objective. Or to still more simplify the
matter, we can use the lamp only of one of these mineral
lanterns and place it as figured in the annexed cut (fig. 50).
Here we have a base board A A, with a fixed support in the
centre B, which is pierced with a hole sufficiently large to
contain the condensers of the lantern. Close up to this
is placed the lamp L. Another support, C, holds the objec-
tive, and this support by means of a sliding piece let into
the base board, can be moved to and fro for focussing pur-
poses in front of the condensers. It will be seen that by
adopting this arrangement, no lantern is necessary. We
simply require the illuminator, which must of course be
closed in, as sold with most lanterns ; a condensing lens ;
and an objective.
The number of beautiful experiments which are possible
with the use of a glass tank, or rather, several glass tanks
of the simple form shown in fig. 51 are surprising. Most
THE BOOK OF THE LANTERN. 191
of these are of a chemical nature, but there are others
which exhibit physical phenomena in a manner which is
perhaps, impossible by any other means, or rather, we may
say, that experiments which can only under normal con-
ditions be viewed by one or two pairs of eyes on the lecture
table, can by means of this tank be made visible to a large
A fine experiment showing the formation of vortex
rings may be shown in the following way. Having filled
the tank with clean water, take a penholder or a piece of
stick pointed for the purpose and dip it into some milk, so
that a drop forms at the end of it. Bring this carefully over
the tank and allow the milk to just graze the surface of
the water, when it will form a white ring in the fluid
which will fall gradually downward, but on the screen,
of course, it will appear to rise upward. This ring as it
travels to the bottom of the tank will give rise to other
similar rings, so that presently there will be quite a number
of circles slowly moving upwards on the screen. This
experiment is one which will illustrate well the formation
of smoke rings, and of the more important phenomena of
whirlpools and whirlwinds.
Another experiment of a similar nature, and giving a fine
effect on the screen, may be performed by filling the tank
to within half an inch of the top with methylated spirit.
Take now instead of a wooden rod one of glass, or a camel
hair brush will do as; well. Dip it into an alcoholic solution
of any of the aniline dyes, and just allow the drop which
hangs from it to touch the inner side of one of the glasses
of the tank. Directly this drop reaches the alcohol, it will
192 THE BOOK OF THE LANTERN.
descend and immediately break out into a number of
branches. These branches will on the screen appear to rise
rapidly upwards after the manner of a number of coloured
rockets, and by varying the colours of the dyes and putting
one or two drops into the tank simultaneously, a most lovely
effect on the screen is obtained.
The decomposition of water is another experiment which
has a most curious effect. For this experiment a small electric
battery is necessary, and the most convenient form to use is
a single bichromate cell, say of one pint capacity. This can
be hidden away in a box beneath the lantern, and as it
gives off no fumes, there is nothing disagreeable in its use ;
moreover its action, if freshly charged, is energetic, and this
action can be stopped when required by lifting the zinc
plate from the solution in which it is immersed. The wires
from the poles of the battery must be long enough to reach
the lantern stage ; the slide for this experiment being simple
in the extreme. The tank to be used shyuld be of rectangular
form, and as a matter of convenience, it should be furnished
with two binding screws on one of its outer sides, so that
the wires from the battery can be readily connected with
them. These screws should be in connection with two
gutta-percha covered wires, which proceed to the bottom of
the tank, where their ends are bare and turned upwards for
about a quarter of an inch. These ends may be so fixed
that they are about half an inch apart. The tank is pre-
viously filled with diluted sulphuric acid (one part of acid
to eight of water), and is then ready for action. Directly
connection is made -with the battery, the two wires will
rapidly give off bubbles of gas, one being hydrogen and
THE BOOK OF THE LANTERN. 193
the other oxygen. It is possible to elaborate this slide by
crowning the two terminals with tiny inverted test tubes,
filled with the acidulated liquid. In this case the bubbles
of gas displace the contained water in the tubes, the hydro-
gen tube being readily distinguished by being emptied of
water at double the rate of the tube devoted to the oxygen
gas. This proves in a very direct manner the composition
of water, which consists of two volumes of hydrogen to
one of oxygen.
In order to show the generation of hydrogen gas alone, a
still more simple arrangement can be adopted. The electric
battery is not used for this experiment. A few pieces of
granulated zinc are dropped into the tank of acid water,
when bubbles of hydrogen will be rapidly given off, their
downward descent upon the screen giving a very peculiar
In like manner carbonic acid gas can be generated by
using a few pieces of marble instead of the zinc, aud sub-
stituting for the sulphuric acid water which has been acidu-
lated with hydrochloric acid. We can also easily show
that one of the products of the lungs is this same carbonic
acid gas. In this case the tank must be filled with lime
water, which will remain perfectly clear until it is blown into
fro n the lungs by means of a tiny glass tube, when bubbles
of air will rise from the water, and the liquid will rapidly
become cloudy, proving that the carbonic acid from the
lungs has formed carbonate of lime, or common chalk, in
It will be noticed that in all tank experiments it is
necessary that the lantern stage should be open at the top
194 THE BOOK OF THE LANTERN.
and such experiments are for this reason best performed
with a lantern having the simple construction shown in
Fig. 49. These experiments are so valuable for educa-
tional purposes, and can so easily be shown with ordinary
oil-lit lanterns that it is to be hoped that manufacturers
will see the necessity of providing for them by the adop-
tion of an open stage.
The composition of Prussian blue can be easily demon-
strated by means of the chemical tank. For this experiment
we shall require a solution of the yellow prussiate of
potash from which the colour takes its name. This is
placed in the tank. Have in readiness a solution of sul-
phate of iron or green vitriol. On pouring the contents
of this bottle by means of a pipette into the tank, a heavy
blue precipitate is thrown down, but as this precipitate is
opaque the colour is not perceptible on the screen ; but by
adding to the blue precipitate a few drops of sulphuric
acid, and following this by a little bi-chromate of potash
in solution, a brilliant transparent blue is immediately
made apparent. The formation of other colours can by
reference to any book on chemistry be readily demon-
The tests for acid and alkaline solutions by means of
litmus can be demonstrated in the following way :
Fill the tank with a solution of litmus or with an in-
fusion of purple cabbage, made by slicing a few of the
leaves, and pouring boiling water upon them. Place either
of these solutions in the tank, when, upon adding a small
quantity of acid, the liquid will be seen to turn red ; sub-
sequent addition of an alkali, such as a weak solution of
THE BOOK OF THE LANTERN. 195
ammonia, will quickly restore the original colour, and these
changes from red to blue, and vice versa, can be continued
by adding acid and alkali alternately, as often as may be
If the tank be charged with a solution of sulphate of
iron and gallic acid be added to it, a black solution of ink
will immediately be produced. Another pretty experiment
demonstrates the presence in hard water of various mineral
matters which will cause certain chemicals to give a
precipitate which they would not do in water that has
been freed from mineral matter by distillation. A good
plan of showing this is to suspend in a tank a crystal of
oxalic acid. As the crystal dissolves in the water long
threads of oxalate of lime will be given off by it, forming
a very curious appearance on the screen. It may then be
shown that by the substitution of distilled for hard water
the crystal will dissolve all the same, but these threads will
not be given off, because there is no lime present to form
them. The action of bleaching powder, commonly called
chloride of lime, is well shown by filling the tank with a
solution of indigo, which has been acidified with sulphuric
acid. Upon adding a solution of the bleaching powder,
the sulphuric acid will liberate the chlorine contained in
it, and will discharge the blue colour of the indigo, leaving
the disc on the screen perfectly white.
The precipitates caused by the admixture of various
chemicals is not effective in the lantern, for the reason that
most of these precipitates are opaque, and therefore they
look black upon the screen.
For instance, we may fill a tank with a solution of
196 THE BOOK OF THE LANTERN.
common salt, i.e., the chloride of sodium, and upon adding
to this a small quantity of nitrate of silver in solution, a
heavy white precipitate of chloride of silver is thrown
down, but as this is perfectly opaque it will only appear on
the screen as black clouds.
Other very beautiful experiments may be performed to
demonstrate the crystallisation of various salts. Plates of
glass may be prepared beforehand with saturated solutions
of the salts, and these plates, slipped into a slide carrier,
can be used for projection, giving very fine effects. But
by far the most striking way of exhibiting these interesting
phenomena is to show' the crystallisation actually in
This is easy enough if the lantern be furnished with a
vertical attachment, but not so easy without such an
appendage. But the following experiments can be readily
performed with an ordinary lantern. Prepare a saturated
solution of sal-ammoniac, and with the help of a camel-hair
brush cover a clean glass plate with the liquid ; place this
glass on the lantern stage, when the heat from the lamp
will speedily cause the water to evaporate and the crystals
to form on the glass. It will be noticed that in the crys-
tallisation of this salt the branches of the marvellous tree,
which grows so rapidly on the screen, always keep at a
particular angle to its stem. Another experiment of a like
nature is performed by employing a solution of urea in
alcohol, in which the crystallisation is quite different, the
plate being quickly covered with bundles of fibres which
are no longer at right angles to the stem from which
they spring, but take all kinds of different directions.
THE BOOK OF THE LANTERN. 197
These experiments are of great use in demonstrating 1
the gradual crystallisation of the various mineral sub-
stances of which the crust of the earth is composed. A
very beautiful experiment, showing the structure of ice,
has been devised by Professor Tyndall. I cannot do-
better than describe the manner of performing it in his
own words : " Take a slab of lake ice and place it in- the
path of a concentrated sunbeam. Watch the track of the
beam through the ice. Part of the beam is stopped; part
of it goes through ; the former produces internal lique-
faction, the latter has no effect whatever upon the' ice.
But the liquefaction is not uniformly diffused. From
separate spots of the ice little shining points are seen to
sparkle forth. Every one of those points is sur rounded by
a beautiful liquid flower with six petals.
" Ice and water are so optically alike that unless the light
fall properly upon these flowers, you cannot see them.
But what is the central spot ? A vacuum. Ice swims on
water because, bulk for bulk, it is lighter than water ; so
that when ice is melted it shrinks in size. Can the liquid
flowers then occupy the whole space of the ice melted ?
Plainly no. A little empty space is formed with the
flowers, and this space, or rather its surface, shines in the
sun with the lustre of burnished silver.
" In all cases the flowers are formed parallel to the sur-
face of freezing. They are formed when the sun shines
upon the ice of every lake ; sometimes in myriads, and so
small as to require a magnifying glass to see them. They
are always attainable, but their beauty is often marred by
internal defects of the ice. Even one portion of the same
198 THE BOOK OF THE LANTERN.
piece of ice may show them exquisitely, while a second
portion shows them imperfectly.
" Here we have a reversal of the process of crystallisation.
The searching solar beam is delicate enough to take the
molecules down without deranging the order of their archi-
tecture. Try the experiment for yourself with a pocket-
lens on a sunny day. You will not find the flowers con-
fused ; they all lie parallel to the surface of freezing. In
this exquisite way every bit of the ice over which our
skaters glide in winter is put together."
One of the most interesting chemical operations to
witness is the development of a photograph, and even
experienced workers will say that they never tire of
watching the gradual unfolding of the wonderful image.
Those who have never before had the opportunity of watching
the effect of the developing fluid on the blank plate, are
delighted when first the operation is brought under their
notice. It is certainly an experiment which never fails to
interest an audience, when properly performed, as it can be,
in the optical lantern. But the operator mast not be
a novice in photography, or he will probably fail, for the
experiment requires experience, land great care in all
A gelatine bromide plate, such as is ordinarily used
for negative work,, is of no use whatever here, for the
film is too opaque for the purpose. A gelatine chloride plate
(such as that described on page 133) is the right thing to
employ. If we compare a bromide and a chloride plate side
by side in the dark room, we shall soon see that there is
little difficulty in distinguishing the one from the other. In
THE BOOK OF THE LANTERN. 199
the first case, the film is so thick that we can see nothing
through it, but in the case of the chloride plate the flame of
the red lamp can easily be seen through the glass ; indeed,
upon first using such plates, photographers are apt to
wonder whether so thin a film can ever yield a picture. As
a matter of fact, the film is as thick as that upon a bromide
plate, only the emulsion of which it is composed is of a
far more transparent quality.
Having then a chloride plate at hand, and having if ne-
cessary cut it down to a size which will enable it to slip
with ease into a chemical tank, the course of operations
will be as follows: 1, Exposure; 2, development; and
Provide a good negative (if it be a portrait of some one
well known to the spectators, so much the better), and place
it in a printing frame, with the chloride plate against it,
film to film. Expose to the light of an inch of magnesium
wire held two feet away from the printing frame, or to the
rays of the lime light for about ten seconds. Now place
the little tank on the stage of the lantern, and against the
inner side of it, that is, next the light place a sheet
of ruby glass. The effect upon the screen will now be
simply that of a blank red disc. The exposed plate may
now be taken from the printing frame and placed in the
tank. Take good care that it is placed there upside down,
so that the image when developed will appear the right way
up. The developing fluid, ferrous oxalate (see page 121),
may now be mixed. This should be at hand in two solu-
tions, so that by mixing the one with the other the de-
veloper is ready without any delay. As it is poured into
200 THE BOOK OF THE LANTERN.
the tank, the surface of the fluid will appear as a descending
line across the sheet. The strength of the developer should
not be so great as for ordinary development, by which I
mean that the proportion of iron can be conveniently
reduced so as to render development less sudden than it
generally is with chloride plates. When once the developer
has been poured into the tank, the red glass can be with-
drawn, for the ferrous oxalate developer is red enough in
itself to form a protection to the plate from the light.
Presently the image will begin to appear, and will gradually
gain in strength. When it is fully developed, as it will be
in about two minutes, the plate can be removed, washed,
and placed once more in the lantern in a tank of fixing solu-
tion. Here it will gradually get clear, as the unaltered
chloride is acted upon by the hyposulphite of soda solution.
To perform this interesting experiment in the most per-
fect manner, a special form of tank may be employed. It
should have a tap at its lower part, to act as a waste pipe.
With this arrangement the chloride plate need not be
removed from the tank at any stage of the process. When
development is complete, the ferrous oxalate can be drawn
off ; then water can be poured in, to be immediately drawn
off and replaced by the hypo solution.
The chloride plate employed can be put into the printing
frame by gaslight, provided that the operation be performed
with ordinary despatch. It should be noted, too, that these
plates, or at least some brands of them, rapidly deteriorate.
But the careful operator will try the experiment in private
before he ventures before the public, and will take care that
his plates are above suspicion.
THE BOOK OF THE LANTERN.
Magnetic experiments are always attractive, and can be
well shown with the lantern, for they gain greatly by the
magnification possible with that instrument. Fig. 52 shows
a simple form of slide which can be manufactured without
much trouble ; it consists of a bar of soft iron, bent as
shown, and pointed at its ends. These ends or poles are
brought to within half an inch of each other. Two
wooden or cardboard reels, wound with a quantity of silk
covered copper wire, complete the arrangement. The
battery already recommended can be used with this mag-
netic slide. Here are a few experiments possible with the
contrivance. Drop upon the poles some iron filings, and
show that they are not attracted until the battery connec-
tion is made, for then and only then has the iron magnetic
properties conferred upon it. Drop a number of small
French nails, technically known as pins, upon the poles,
when they will meet and assume curious forms, until the
current is broken, when they will fall upward, as it will
appear. A tiny disc of iron attached to the end of a silk
thread and hung between the poles will take up a rigid
position directly the battery connection is made, a similar
202 THE BOOK OF THE LANTERN.
one of bismuth assuming the opposite direction under the
same conditions. This last experiment is to show the
difference between a magnetic and dia-magnetic body.
But the most beautiful magnetic experiments are only
possible with a vertical attachment fitted to the lantern.
Obtain a couple of flat bar magnets two inches in length.
Place one of these in the centre of the horizontal stage, and
focus sharply on the screen. The appearance is that of a
thick black bar. Now sift through a muslin bag some iron
filings, so that the screen appears covered with black spots.
Tap the stage with the finger nail, so as to disturb the
particles of iron, and they will be seen to gather round the
poles of the little magnet, and to form the beautiful magnetic
curves. A still more striking experiment may be per-
formed with two magnets so placed that their poles of
opposite names, N. and S., face one another, while they
are at the same time about one inch apart. Now scatter
the filings as before, and the effect of the graceful curves
embracing one another between the two poles is simply
magnificent. Remove the magnets, wipe the filings from
the stage, and once more arrange the bars in the same
position, but with poles pf the same name facing one
another. When the filings are now scattered over the
magnets, a great contrast to the last experiment is apparent.
Where just now all was harmony, there is visible antago-
nism. " Poles of opposite name attract one another, and of
the same name repel one another." And this repulsion is
most beautifully shown. The curves no longer embrace
one another, but meet and turn back upon themselves,
forming a line of confusion where the meeting takes
THE BOOK OF THE LANTERN. 203
place. The experiments can be varied by altering the
position of the magnets, or by using knitting needles which
have been just before magnetised at the lecture table. It
will be noticed that these curve experiments require no
battery power. They are performed with what are known
as permanent magnets, in contradistinction to the electro
magnet used with the special form of slide shown at
In describing some of the experiments possible with the
optical lantern, I have purposely refrained from detailing
any of the splendid effects due to polarised light for these
have been already dealt with by my friend Mr. Lewis
Wright, in a manner which it would be impossible to
improve upon. 1
1 " Light : a Course of Experimental Optics, chiefly with the
Lantern." Macmillan & Co.
THE LANTERN AS AN AID TO PHOTOGRAPHY.
HEN a photographic aspirant first enters upon the
practice of what used to be known as the " black
art," but which now, thanks to the cleanliness of
dry plate work, no longer merits that stigma, his friends
and relatives all look anxiously for some tangible results
from his mysterious operations. To them a negative,
albeit it may show lovely gradations of tone, and
beauties of detail, which a master's eye would revel
in, is negative in a far wider sense than its producer
would be inclined to allow. A production in which
bright skies and white skins are black as night, is a
thing which cannot be understood or tolerated, and until a
print of that negative is produced, and sometimes alas !
even then, the domestic critics are inclined to consider the
amateur worker a fraud. The painstaking photographer,
after he has succeeded in obtaining a few negatives, will be
anxious on this account, if not for his own satisfaction, to
print some positives from them. These will afterwards be
THE BOOK OF THE LANTERN. 205
mounted in an album, and much pleasure will doubtless be
derived from them. They may possibly not be grand
specimens of solar work, but they will serve to remind the
author of many a pleasant ramble, and many little incidents
of places visited and people met with, which otherwise
might have passed into oblivion. He will be able " to fight
his battles o'er again," as he tells his friends of difficulties
encountered by the way. But at the best this means a
great deal of work, and work, too, which to a great extent
is mechanical, and therefore tedious. The printing, toning
and fixing of a batch of prints is no light matter to an ama-
teur, who has generally to do everything for himself. Some
prints are sure to get over-exposed, others suffer from the
opposite failing, and even if all goes well in the preliminary
operation of exposure, there is that terrible toning bath to
come. This bath sometimes, for some obscure reason, will
refuse to give the desired colour, and our batch of prints,
instead of being " joys for ever," turn out to be sandy-
looking, bilious objects, which we are afraid to show to
What if some magician were to appear suddenly at the
elbow of the disgusted worker, and tell him that there was
a way of producing positives from those negatives without
all this trouble ? That such positives could be shown en-
larged to an almost indefinite extent, and that pictures five,
ten, or fifteen feet in diameter could be shown in perfection,
the original negative from which they are taken measuring
only three and a quarter inches. There is no need for any
magician, for the thing can be achieved, not easily, for the
work, like most photographic manipulations, requires a
206 THE BOOK OF THE LANTERN.
great deal of patience and practice before success is
attained. The requisites are good photographic transpa-
rencies on glass, and a good optical lantern wherewith to
The lantern method of showing photographs has the ob-
vious advantage that a large number can at the same time
view the same picture under the best conditions. They can
exchange opinions as to its merits, and can point out little
bits of detail which would be almost invisible in a paper
print from the original small negative. A great many
amateurs, too, take only small negatives. They do not care
to be burdened in their rambles with a large camera,
which, with its inevitable dark slides or changing box,
forms a very heavy travelling companion. Many, there-
fore, are wise enough to content themselves with either a
quarter-plate apparatus, or one which gives pictures mea-
suring 5 by 4 inches. Prints from these small negatives
are rather insignificant when mounted in an album, but
such negatives are just what are required for lantern trans-
parency making ; so that the tourist with his little camera
is, with the help of the lantern, placed on the same footing
as the toiler with large and heavy .apparatus. He can in-
crease the size of his pictures, or rather the images of such
pictures, to any reasonable extent. I know of an amateur
photographer who spent three months on a Mediterranean
tour. He took with him a quarter-plate camera, and its
accessories, together with a stock of gelatine plates. He
brought back with him about one hundred and fifty capital
negatives, which were taken in Algeria, Tunis, Malta.,
Sicily, and Southern Italy. On his arrival in England
THE BOOK OF THE LANTERN. 207
these were all printed as lantern transparencies, and he is
now able to entertain his friends with an account of his
wanderings, and to illustrate his remarks in a very pleasant
and novel manner. If the same negatives had been merely
printed on paper in the usual manner, and shown in an
album, they would, by reason of their smallness, have met
with but scant appreciation.
I may instance another way in which the lantern can be
utilised without the necessity of taking original negatives.
Most travellers abroad collect photographs of any place they
may visit, and an enormous trade is now done in such
pictures. These are brought home in due course, mounted
in an album, and too often, alas ! gradually fade into sickly
yellow ghosts of their former selves. Now, if these pictures
were copied by a small quarter-plate camera, the negatives
thus obtained could in their turn furnish positives on glass
for use in the lantern. Transparencies so produced are
never, it is true, so good as those from original negatives,
for the texture and the gloss of the paper prints will gene-
rally to some extent show themselves in the reproduced
negative, but still it is wonderful what good results can be
obtained in this way. Indeed, I may say that it requires a
critical eye to detect that a second negative has been em-
ployed. I have already detailed the best method of pro-
ducing these negatives from paper prints, and have given
some useful hints by which the disadvantages to which they
are subject can be reduced to a minimum (see page 121).
Paper prints naturally remind one of those portrait
albums which are found in every house. Why should not
these pictures also be adapted to the lantern? What a
208 THE BOOK OF THE LANTERN.
fund of interest and amusement could be obtained from
an exhibition of life-sized pictures of friends and acquaint-
ances well known to the family circle ! There is really
no great difficulty in obtaining such pictures when the first
principles are understood; and when practice has given
experience, negatives from prints can be produced with a
rapidity and certainty to which the most experienced land-
scape photographer is a stranger.
Nor must the young folks be forgotten. Although the
" man swallowing rats " and the other monstrosities, known
in the trade as " comic slips," still have an attraction to the
eye of youth, surely we can manage by the means now
easily within reach, to place before the youngsters some-
thing better worth looking at. The quaintly picturesque
little youths and damsels drawn by Kate Greenaway would
have additional charm for their living playfellows if shown
life-sized on a screen ; and nursery legends, as interpreted
by Cal&ecott's clever pencil, would acquire a new interest if
shown in the same fashion. Perhaps as amateur photo-
graphy increases its number of workers, as it is rapidly
doing, artists may find it convenient to draw subjects
specially for reproduction as lantern transparencies.
There is one feature in this particular class of photo-
graphic work which I have not yet dwelt upon, and that
is, the possibility of producing these transparencies inde-
pendently of daylight. So long as the spring, summer, and
autumn days are upon us, the possessor of a camera finds
much other work to employ his time. His labours are
mostly in the open field, adding to his stock of negatives,
and he looks forward with regret to the many dark hours
THE BOOK OF THE LANTERN. 209
which winter must bring, in which such work is impossible.
But now is his time for lantern preparation. The negatives
are looked up and sorted out, and by means of a gas flame
or paraffin lamp he can print off transparencies more
quickly than even on a favourable day he could produce
paper prints. There is no tedious toning or extended
washing necessary, and therefore the work does not entail
half the trouble that he is accustomed to in ordinary print-
ing. In addition to these advantages there is one other.
A transparency on glass is far finer in effect than any
paper print, for the reason that the picture is absolutely
without texture. Magnify a paper print and the texture
of the paper becomes at once evident; treat a good
glass positive in the same way and its beauty is only
Lastly, the possessor of a lantern has another field of
work in which it can be usefully and efficiently employed,
namely, in making enlargements. Not the evanescent
and fleeting images already described, but permanent en-
largements of a quarter-plate negative, which is sufficiently
rich in detail and interest - to warrant its production in an
enlarged form. By means of an oil lantern, and a sheet
of the excellent gelatino-bromide paper now to be pur-
chased, an enlarged positive from a small negative is easy
to produce. And here, again, the work is quite indepen-
dent of the fickle sun, and can be accomplished in any
room not specially set apart for the purpose.
I have by no means exhausted the list of services
which a simple form of optical lantern is able to render,
but I have enumerated several which will serve my pur-
THE BOOK OF THE LANTERN.
pose in pointing out its extreme utility. In a subsequent
chapter on enlarging I dwell in detail upon the various
operations necessary, and illustrate them by diagrams,
so that readers may acquire a practical knowledge of the
THE ART OP MAKING PHOTO-MICROGRAPHS.
PHOTO-MICROGRAPH is the picture of a
microscopic preparation, as seen by the eye
when enlarged by means of the microscope ;
its converse, being a much-reduced image of an object
photographed on glass, which is called a micro-photograph,
and which can only be seen when placed in the microscope.
This latter, however, is a mere curiosity, and, although
it excites some wonder when looked at, has no educational
or scientific value, except perhaps as a proof of the fine
structure of a photographic film. A photo-micrograph, on
the other hand, affords a valuable means of displaying to a
large audience the delicate structure of various organisms,
both animal and vegetable ; besides which that of coal and
other minerals can: be well exhibited. Lantern micro-
scopes, some of very beautiful construction, have been
brought forward from time to time, and one of them, at
least, I shall refer to in a subsequent chapter.
But although lantern microscopes may give very fine
results, it is an indisputable fact that the amount of light
which is able to get through the tiny aperture of a high-
power objective, is small. And when this small amount
212 THE BOOK OF THE LANTERN.
has to be spread over a screen of even moderate propor-
tions, the illumination of the whole is so insufficient that
although near observers are able to note that the disc is
covered with a network of exquisite detail, those who are
placed a few yards away cannot distinguish anything of the
kind. If this is the case with those whose sight is perfect,
how much more true it must be of the large number of
persons who are less favourably endowed. Probably the
difficulty may be remedied at an early date by the use of
the electric light, which is far more brilliant than the best
limelight possible, and I know that experiments are
being carried on in this direction ! In the meantime, we
must look for other means of projecting the image of
microscopic objects on a screen if we require such illus-
trations for a large number of spectators. I recommend
the employment of photo-micrographs of the size of the
ordinary lantern-slide, viz., 3J x 3J in. as the best way out
of the difficulty. I am, of course, aware that a photo-
graph of an object is not in many cases so good as the
object itself. While this is true, it is also true that there
are a great many preparations which cannot be satisfactorily
shown by any kind of projecting apparatus, but they can
be made to yield photographs which can be exhibited by
the optical lantern. There are many different ways
of producing photo-micrographs. Some workers use the
most complicated apparatus, whilst others seem to obtain as
good results with rough home-made appliances. But so it
is in every branch of science. Somebody wittily divided
microscopic workers into two different species. He dubbed
the first of these " Brass and Glass," and the second
" Bug and Slug." The first are the possessors of the
THE BOOK OF THE LANTERN. 213
magnificent microscopes with all kinds of movements and
expensive attachments, and who toy with their instruments
rather than work with them. The second class are the
hard workers, who will be content so long as they possess
one or two good powers, and have anything in the shape
of a stand to hold them in position. They will accomplish
far more real work with a simple magnif ying-glass than one
of the "Brass and Glass" fraternity with his gorgeous
array of instruments.
One of the most simple methods of obtaining a photo-
graph from a microscopic object is to use a little camera, a
cardboard box with a hole at the bottom to fit over the
microscope tube is sufficient, placed above the microscope
as it stands upright on a table. To simplify matters, the
eyepiece' of the microscope should be removed, a method of
procedure which I recommend in all cases. The upper part
of the cardboard box should be furnished with a lid on a
hinge, and should have a curtain of black velvet all round it,
to prevent any access of light. On its inner sides, half an inch
below the lid opening, should be glued four little pieces of
wood to support the focussing screen \ the same support
serving later on to hold the sensitive gelatine -plate in posi-
tion. Now let us go through the required operations. The
image is focussed by daylight, or lamplight, as the case
may be. The focussing glass is then removed, and while
the room is darkened the sensitive plate is inserted in its
place, the lid of the box shut down, and all is ready for ex-
posure. The time of exposure is of course a matter depend-
ing upon a host of circumstances to which we need not here
refer. The exposure having been made, the plate is de-
veloped in the usual manner.
214 THE BOOK OF THE LANTERN.
Another plan is to bring down the microscope to the
horizontal position, and most microscopes allow of this
being done, and to push the end of its tube into the flange
opening of an ordinary photographic camera, with the lens
of the latter removed. But both these methods have
a disadvantage, among many other drawbacks, which
will at once disappoint the operator. The image afforded is
so small. The tube of the microscope gets in the way, so
to speak, and a large portion of that image is cut off. This
can be remedied by an arrangement of the apparatus which
I am now about to describe, and by which I have taken a
number of photographs which leave little to be desired in
point of excellence, while the necessary manipulations are
carried forward with that ease and nicety which go far to-
wards the production of first-class results.
Let it be at once pointed out, in spite of the opinions of
our " Brass and Glass " friends, that an expensive instru-
ment is not required for this work. (Indeed, I will presently
point out how it is possible to obtain capital photo-micro-
graphs without any microscope at all, although the essen-
tial part of that instrument, the objective, must be
employed.) What is wanted is a good firm stand, and a
fine adjustment, and even this is not very necessary, unless
high powers are employed. But the majority of readers
will look for some ready means of photographing objects of a
popular character. The proboscis of a blowfly, the industrious
flea (or bee is it ?), section of the echinus spine, and so on ;
such things as can be readily photographed with the " inch"
objective. And to readers who are content with such as
these I chiefly direct my remarks, leaving them to study
the excellent treatises and articles upon the subject of
THE BOOK OP THE LANTERN.
photo-micrography, which have been published, when they
feel themselves capable of
higher flights in this most
The microscope which
I use is of a very ordinary
pattern, as may be noticed
in the diagram (fig. 53) ;
but three little alterations
in it make it very con-
venient for photographic
work. In the front leg
of the claw-shaped stand
a 3-16ths inch hole has
been bored, so that the
instrument can by means
of a screw be rigidly
fixed upon a base board.
The next alteration is in
the length of the tube.
Originally seven inches
long, I have had it
separated at nearly the
centre, so that it can be
reduced to three inches ;
but an inner tube over
which the outer one
tightly fits, allows me to
use the microscope for ordinary purposes with a tube of
216 THE BOOK OF THE LANTERN.
normal length. The third modification which I have intro-
duced, is a groove cut in the milled head of the fine adjust-
ment screw, the purpose of which we shall presently see.
For photographic work, the mirror is thrown out of gear,
as indicated in the diagram, for it is not required.
Referring once more to this diagram, 1 1 is the table on
which the whole arrangement rests, and it is best to have
a table for the purpose, or at any rate a level base board?
upon which all necessary fixtures can be made; c is a
camera which should open out to great extent (most
modern cameras are made to do so, so as to give the
photographer the benefit of using long-focus lenses) ;
m is the microscope, s the stage, p the mirror thrown
back out of use, n the coarse adjustment, and k the fine
adjustment. We can now see the advantage of providing
this milled head of the fine adjustment screw with a
groove. In this groove is placed a silk cord, which
works in a corresponding groove in the little wheel
which is fixed on the end of the focussing rod o o. By
means of the knob d at the other end of this rod, the
operator is able to work the fine adjustment to a nicety,
while he is far away from the microscope, examining
the image on the ground-glass screen of the camera.
A word about this screen will not be amiss. Ordinary
ground-g'ass will not do for this class of work, for it is
far too coarse. It should therefore be replaced by a
focussing screen prepared as follows : Obtain a sensitive
gelatine plate, such as is used for negative work, expose
it to the light of a gas flame for a second, and then pro-
ceed to develop it. Develop until it is uniformly
THE BOOK OF THE LANTERN. 217
darkened to a small extent, fix and wash in the usual
manner, and then bleach it in a solution of mercuric
chloride. The result will be a plate covered with an
exquisitely fine translucent surface, upon which the
finest details will be visible. The exact amount of
exposure and development to secure this end may not
be at first hit upon, but one or two trials will be sure to
end in a satisfactory result. Some workers prefer to use
a plain glass upon which fine lines have been ruled
with a writing diamond. In any case the worker will
find the advantage of supplementing his eyesight, how-
ever good, by a focussing glass. In this way a far sharper
focus is obtainable than by the unaided eye.
To describe the rest of the diagram, let me point out
that / is an ordinary microscopic paraffin lamp, furnished
with a reflector f, and that h is a condensing lens, having
attached to it a diaphragm-plate, e.
Mr. T. Charters White, M.R.C.S., has published a
method by which photo -micrographs can be produced
without the aid of either a camera or a microscope, which
is very creditable to his ingenuity. I had recently the
pleasure of hearing him 'describe the instrument, while
he practically demonstrated how effectually it would
work. The apparatus was home-made, and such as
could be produced by any one with the minimum of out-
side help, although there are many accustomed to the use
of tools who could easily make it without any help at all.
I append a diagram which shows the various parts of this
simple contrivance (see fig. 54).
It consists in a lidless box sufficiently large to con-
THE BOOK OF THE LANTERN.
tain an ordinary microscopic lamp, an objective whicli
screws into one end of the box, and a movable stage
to hold the object, having a screw attachment, so that
it can be moved to and from the objective in order
that the image may be sharply focnssed upon a plate
held in a frame outside. This frame is fixed to a
grooved board, which can be moved in and out of the base
board, and this movement determines the distance of the
image projected from the lens, and therefore the size of
that image. The apparatus may indeed be compared to
an optical lantern in its arrangements, except that the
condensing lens (an ordinary one on a stand such as is
used for microscopic work) is contained within the box,
and that the object to be projected is on a special form of
movable stage, as above mentioned. This stage, or fine
adjustment, consists of two parallel and horizontal bars,
with a fine screw of the same length laid between them,
and which works in a threaded orifice in the lower part of
the stage. The end of this screw nearest the light is
THE BOOK OF THE LANTERN. 219
crowned with a grooved wheel, which is geared by a piece
of cord to another similar wheel at the end of a focussing-
rod, which is brought within easy reach of the plate-
carrier outside the box.
These various arrangements will be rendered clearer by
reference to the diagram, where O is the objective, S the
stage, F the focussing-rod, L the lamp, C the condenser,
and A the frame holding the gelatine plate, or the
focussing -glass, as the case may be, for one takes the
place of the other. And let me say, in passing, that this
method of withdrawing one glass so that the other can
take its exact place, is the best that could be adopted, for
the merest fraction of difference in register would be
perceptible in photo-micrographic work, while it might
remain undiscovered in negative taking of the ordinary
Mr. White's apparatus was, at the time I saw it, fitted
with a 1-inch objective; but he told me that he had
used higher powers with it. It certainly is capable of
very fine work, as was proved by an album full of speci-
mens which he exhibited. His focussing-screen was a
plain glass, ruled with -lines by a diamond, and he
employed a focussing eye-piece. But it is evident that,
with this method of working, the operator could employ
an opaque screen, such as a piece of opal glass, for the
room in which the work is carried on takes the place of
the camera, and he is practically within it, and can
look upon the side of the screen which is next the
light. By means of a scale upon the sliding-board which
carries the gelatine plate, it is easy to note, without actual
THE BOOK OF THE LANTERN.
measurement, the amount of magnification of the image.
And this magnification can be carried to any reasonable
extent, for the worker is not limited, as he would be if
using a camera, by the length to which that camera can
But perhaps the simplest arrangement of all is that
recently introduced by Messrs. Mawson & Swan, and
which is shown at fig. 55. A is a light metal disc, which
can be screwed on the camera front in place of the ordinary
lens. The opening in -its centre is furnished with the
regulation microscopic screw, so that any ordinary micro-
scopic objective can be readily fixed to it. Upon two
horizontal bars, projecting from this metal disc, there
slides another similar disc B, also with an opening in the
centre. This second disc has fitted to it a pair of small
spring clips for the reception of the microscopic slide
which it is desired to photograph. Focussing is effected
by sliding the disc B to and fro in front of the objective
THE BOOK OF THE LANTERN. 221
on A. It will be readily seen that the apparatus may be
rendered more effective by the attachment of a screw, or
fine adjustment for more accurate focussing ; but with the
lower powers this would not be needed. It is an addition,
however, which the makers will supply when required.
All the objectives made by Messrs. Swift, as well
as those by a few other makers, are corrected for
photography, but in those of older date the visual focus
does not agree with the chemical focus. As a rule, no
difficulty will be found with the higher powers, and with
the others a few trials will soon show what allowance in
focussing must be made. As a rough guide to what must
be done to correct this fault, which is rendered evident
by a sharply -focussed image appearing blurred in the
negative, proceed as follows : First focus the image as
sharply as possible, and then cause the objective to
approach the object until the latter seems to be sur-
rounded by a reddish light; now take the photograph,
and it will be sharply defined, although the image did not
look so on the focussing screen.
The ferrous-oxalate method of development, described on
a former page, is very suitable for negatives taken for
photo-rnicrographs. These negatives are then made to
furnish lantern slides in the manner detailed in a former
ENLARGING PHOTOGRAPHS WITH THE LANTERN.
(HE amateur who works with a quarter plate
camera will often congratulate himself upon
the slight burden which it entails, even when
several double backs and spare plates accompany
it. But he will also regret that the little pictures
which it yields, measuring only 3 by 4 inches when
trimmed and finished, are, after all his trouble, so
very insignificant-looking. He may possibly have availed
himself of the instructions already given for the produc-
tion of lantern slides from such small negatives, and thus
ascertained that his pictures are full of detail, and will
bear enlargement. But lantern images are fleeting things,
dissolving views, in truth, and he would fain endeavour
to find some more permanent way of increasing the size
of his pictures. Thanks to the wonderful photographic
revolution achieved by gelatine emulsion, this can be done
without very much trouble or difficulty.
In using the lantern for exhibition purposes we employ
THE BOOK OP THE LANTERN. * 223
for slides transparent positives on glass, and it stands to
reason that, if the sheet or surface upon which the image
is thrown were, by chemical means, to be made sensitive
to light, we should obtain much the same result that we
get by means of our camera, a negative image, which can
be rendered visible by development. If, on the other hand,
we employ one of our little negatives as a lantern slide,
we can produce from it a positive. Such is the theory
which we will now endeavour to reduce to practice.
The lantern employed can be of the ordinary kind used
for projection, but in this case, where the condenser only
measures 4 inches, it is obvious that a negative measuring
less than that size will be the only one available. The
operator will therefore be better off with a lantern made
specially for enlarging purposes, the condenser of which
must be at least 5 inches in diameter to accommodate a
quarter-plate negative. It might, in many cases, be prac-
ticable to fit the ordinary lantern with a condenser of that
size when it is proposed to use it for enlarging purposes.
Whatever be the arrangement, there must be in front of
the lens of the lantern a flat board upon which the image
can be projected, and which .will serve as a support for the
sensitive surface at a later stage of the operations.
A convenient form of upright easel is shown at fig. 56. It
can be moved backwards and forwards between a couple of
laths nailed on the floor, while the enlarging lantern
remains stationary. A light-tight box above it contains a
roll of sensitive paper, which can be pulled down and cut
off in lengths as required. This easel has a hinged frame,
so that when a sufficient length of the paper is drawn down
224 THE BOOK OF THE LANTERN.
over the face of the easel, which serves as a focussing
board, the frame shuts it in and is clamped. In this way
the paper is heM tight without the necessity of using pins,
or other loose fastenings.
Fig. 57 shows a larger view of this box, with its supply
of sensitive material. But the beginner would no doubt,
first of all, experiment with a simple board, and one
measuring 12 inches by 10 inches would be ample.
The sensitive surface to be employed when a direct
positive is required, is paper specially prepared with a
THE BOOK OF THE LANTERN. 225
coating of gelatino-bromide of silver emulsion. If an
enlarged negative is desired, either an ordinary gelatine
(glass) plate of the required size may be employed, or a
paper negative can be made in the manner to be presently
described. Messrs. Morgan & Kidd, of Richmond, were
the first to introduce " argentic gelatino-bromide paper,"
and therefore the circumstance should be noted to their
credit. It can now be obtained from most other dealers,
and its manufacture is so well understood that it will be
found generally reliable. It can, of course, be used for
contact printing as well as for enlarging purposes. But
perhaps the sanguine amateur may prefer to manufacture
it for himself, and there is no reason why he should not
succeed in doing so, if he is already master of the secret of
making an emulsion which neither fogs nor frills. Here
is a necessarily brief outline of the method of going
to work :
Procure some good plain Saxe paper. Having made
and filtered your emulsion, allow it to set to a jelly in a
226 THE BOOK OF THE LANTERN.
dish. With a good stiff hog-hair stencil-brush break up
the cold jelly, and rub it vigorously over the paper, just as
you would break up cold starch jelly in mounting prints.
Now drag the paper slowly over an earthenware foot-
warmer, which has been duly charged with boiling water.
The heat will cause the little specks of jelly on the paper
to melt and mingle, and the whole will present a smooth
surface. The paper must now be hung up to dry, or it
may be used at once. I need hardly say that all these
operations must be conducted by non-actinic light. The
majority of workers, however, will prefer to buy their
argentic paper ready-made, and, by doing so, save them-
selves possibly much vexatious disappointment.
Any room will serve for the purpose of making an
enlargement ; but it is preferable to conduct the work
at night, because then is saved the trouble of darkening
a room so that it is really fit for photographic opera-
tions, by no means an easy matter. Having a dark
room, the further requirements are a lantern, a screen
as aforesaid in front of it, with a sheet of white paper
pasted over its surface, a good red lamp, a developing
dish, the necessary chemicals, and, lastly, plenty of water
and a pail for waste solutions. If the room has in
it a tap and sink, so much the better. The negative
(which should be a good one, or it will not be worth
enlarging) is placed in the lantern like an ordinary slide,
taking care that the film side is turned towards the screen,
and away from the light. Now carefully focus its image
011 the white board. Having placed lantern and screen at
such a distance from one another that the image is of the
THE BOOK OP THE LANTERN. 227
required dimensions, and having seen that that image is
as sharply focussed as possible, it will be as well if a slip
of sensitive paper, say, 1 inch wide, is first of all exposed
as a pilot.
In the hurry and bustle incidental to, if not inseparable
from, every -day life, we all have a tendency to work too
much by rule of thumb, and it must be confessed that rule
of thumb often turns out very good results. But, in spite
of this, and of the old adage to the effect that an ounce of
practice is worth a pound of theory, we cannot afford to
give theory the go-by entirely. Theory is a useful servant,
but a bad master, for those patient, plodding creatures who
think of nothing else seldom turn out work which has the
stamp of genius upon it. Theory holds them down in her
rigid grasp, and they have not the pluck to try anything
or dare anything that seems opposed to her teachings. If,
on the other hand, theory be regarded as a reliable servant,
to be consulted when difficulties occur in practice, her
value will soon be recognised.
These thoughts came into my mind once when watching
a young experimenter, who was endeavouring to make
some enlargements on bromide paper from small negatives,
by means of an oil lantern. The negative was placed
on the stage of the lantern, and its image was projected
upon the side of a wooden packing-case, which stood on
the table in front of it. My young friend was endeavour-
ing to make from his small negative (J-plate) enlarged
copies of different sizes ; and, to obtain the different sized
images, he had, of course, to move the focussing surface
either to or from the lens as the image was required to
228 THE BOOK OF THE LANTERN.
be smaller or larger. But with regard to exposure he
worked entirely by rule of thumb, or rather, I might
sa y> by no rule at all. It was all guesswork, and,
although he tried many pilot slips of paper with watch in
hand, he failed to turn out any really correctly-exposed
pictures. His failure was chiefly due to his utter ignorance
of the law in optics, which has been already considered
on page 118.
Referring once more to fig. 39 on that page, let the four
squares numbered 1, 2, 3, and 4, be printing-frames
placed at distances of 1, 2, 3, and 4 feet from a
candle-flame. Let us suppose, also, that we have ascer-
tained by experiment that the plate or paper in the first
position (No. 1) is sufficiently affected by the light if it
remain there for one minute. (This is, of course, merely
stated as a case in point. Bromide paper at such a distance
would be sufficiently exposed, under a normal negative, in
about eight seconds, while a chloride plate under such con-
ditions would want two minutes or more.) Then, if we re-
move the frame to position No. 2 at 2 feet from the light
source the necessary exposure will not be doubled, as some
might think, but quadrupled. For the square of 2 is that
number multiplied by itself, i.e., 4. The right exposure,
therefore, will be four minutes. Removing the frame to
position 3, we must once more square that number in
order to arrive at the right number of minutes, for ex-
posure at this increased distance. 3 x 3 = 9. Therefore
nine minutes will be the time. It is easy to see that when
the printing-frame is removed to the farthest distance of
all, which is 4 feet from the light source, the exposure
THE BOOK OF THE LANTERN. 229
will be sixteen minutes. To make the diagram more
explicit, the vertical squares 1, 2, 3, and 4, have been so
subdivided that the number of spaces in each indicates
the number of units of exposure, be that unit a second, a
minute, or an hour. The same rule holds good for en-
larging operations. Thus, supposing that we are working
with an optical lantern, and that the necessary exposure
at 1 foot from the lens is half a minute ; at 2 feet the
time will be two minutes ; at 3 feet four minutes and
a half ; and so on. The practical worker will have this
little bit of theory in his mind whenever he is operating,
and he will soon be convinced that the theory is strictly
Another help in enlarging, which will be found useful,
is a little piece of apparatus, if it can be dignified
by that name, which I have lately made, and which I
call an exposing-gauge. It is so simple in construction
that any one can make it out of a couple of strips of card-
board. The arrangement is shown in fig. 57. The size
of the gauge is immaterial, but a length of 20 inches
will be found convenient. A slip of card of that length,
and about 1 inch in breadth, is cut with pointed ends,
each point having a hole pricked in it as shown. By these
holes, and with the assistance of a couple of drawing-pins,
the contrivance can be readily attached to any flat surface
upon which the enlarged image from the lantern is
focussed. Placed above this slip is another piece of card
slightly shorter, and with a round hole in the centre. The
two strips are bound together with pieces of tape glued
over their upper and lower edges, the two ends being left
230 THE BOOK OF THE LANTERN.
open, like a sleeve, for the reception of a slip of paper,
like that shown in fig. 58.
I I- '.I ' I -M l
Fig. 59, as indicated, really consists of two slips of paper
gummed together end to end. One is sensitive bromide
paper, ten inches in length, which has been spaced out
into five divisions, and marked , b, c, d, e, with an aniline
ink pencil. The other part is ordinary white cartridge
paper, slightly longer than the sensitive slip. Its purpose
is to serve as a handle by which to pull the sensitive paper
through the sleeve, and also to furnish a white surface
upon which a small part of the picture can be focussed,
that small part being confined to the central circular hole
in the upper card.
Now let us see how the gauge is used in practice. It is
first pinned on the focussing board so that a distinctive
part of the image is thrown upon the central hole. In the
case of a portrait this should be the eye. Having focussed
carefully on the blank paper, the first division of the
sensitive slip, which will be that marked e, is pulled in
front of the opening. Let this be exposed for, say, fifteen
seconds; then pull the slip onwards, and expose d for
twenty seconds, c for twenty-five seconds, and so on. The
gauge is then taken into the dark room, its slip of sensitive
paper taken from its yoke-fellow, and carefully developed.
THE BOOK OF THE LANTERN. 231
It will then soon be seen which of the lettered spaces has
received the correct exposure ; and a memorandum noting
time and distance of lens from screen can either be
attached to the negative, or entered in a book against a
number corresponding with a number scratched on the
The same principle can be applied to contact printing
in a frame on bromide paper, by gas or lamp light. When
the frame has been charged with its negative and the
bromide paper, support it upright at a distance of, say,
18 inches from the turned-down flame. Now, place
in front of it an opaque card, sufficiently large to more
than cover the frame. This card should have a hole about
1 inch in diameter cut in it in one corner. Turn up the
light and expose for five seconds. Alter the position of the
hole and give ten seconds, and so on. When the paper is
subsequently developed the several exposures can be
readily identified, and the negative can be labelled to the
effect that it requires so much exposure at a given distance
from a flame. Thus Bromide paper, 18 in. 25 sec. This
negative will then be an infallible guide for the exposure
of negatives of a similar 'type; for a systematic worker,
unless he be quite a beginner, will fall into the way of
producing negatives of much the same character and
strength, and printing from them by lamp light will then
become an easy matter to him.
After this somewhat long but not unnecessary digression,
I will resume my directions for enlarging on bromide
paper, and for the sake of simplicity will suppose that the
operator is not supplied with the special form of easel
232 THE BOOK OF THE LANTERN.
which I have referred to, but is using a mere board for the
The paper is supplied in cases, either in flat sheets, or
rolled with the sensitive surface inwards. A piece of the
required size is pinned on the focussing board ; and the
best way to do this is to pin the two upper corners
first, and to unfold the paper over the board, pinning it
down at the edges as required. Drawing-pins will do, but
ladies' bonnet pins are much more easily handled in the
semi-darkness of the room. Now uncover the lens for the
proper time, and be careful that the lantern is quite free
from vibration. If you wish the picture to be vignetted,
this is most easily managed during exposure. A piece of
brown paper, a foot square, is cut in the centre with an
oval opening, with a serrated edge. Hold this in front of
the lens, and keep it in gentle movement, so that the
pointed edges of the paper are always changing their places.
This will cause the edges of the picture to be ill-defined,
and a white margin will be left outside them.
I need hardly point out that in enlarging by this method
the operator has a wonderful amount of controlling power
at his disposal, in bringing out certain parts of the picture
with extra density, and reducing those parts which may
require such treatment. Thus the distant portion of a
landscape may be lightened by a card moved with discre-
tion over that part of the image during exposure. If, too,
some point in the negative is of unusual density, it can
receive extra exposure by using a card with a hole in it,
in front of the easel.
At the end of the exposure the lantern is capped, the
THE BOOK OF THE LANTERN. 233
paper is unpinned, and carried to the developing dish. It
is now saturated with cold water on both sides, and clean
hands may assist in spreading the water over the surface
until it lies perfectly flat on the bottom of the tray. The
water is now drained off and the developer applied. The
ferrous oxalate method is by far the best to adopt, but the
proportion of iron should be reduced to about one-sixth, or
even one-eighth of the oxalate solution ; and to insure the
best results, the exposure should be such that only a very
small dose of bromide solution is necessary. Some workers
prefer to bring the image out slowly by using an old
ferrous oxalate solution. I myself prefer it mixed per-
fectly fresh, and am quite certain that if the best results
are looked for, fresh developer should be mixed for every
print required. The development must not be carried too
far, for the image gains in density under fixation. When
development is judged to be complete, drain off the liquid,
and immediately, without washing, flood the surface of the
picture with an acid solution.
Acetic acid (glacial) ... ... 1 drachm.
Water ... ... ... ... 16 ounces.
The addition of this solution keeps the whites of the pic-
ture pure. In a minute or two pour the acid away, wash
the print, and fix in fresh hypo of the usual strength. The
print ought to be fixed in about ten minutes ; if it is allowed
to remain in the hypo longer than necessary the half-tones
are quickly destroyed. Now wash the paper in several
changes of water, and let it soak for a couple of hours at
least before drying.
It is not very difficult to print in clouds, from a separate
234 THE BOOK OF THE LANTERN.
negative, on an enlarged positive on bromide paper. The
process depends upon the circumstance that the paper
remains sensitive to light, but in a diminished degree,
after the developing solution has been applied to it. Pro-
ceed as follows : Expose your landscape as usual, but stop
development before the required density is obtained, and
wash the paper. Now placing your cloud negative in the
lantern, pin up the paper once more, shielding the land-
scape portion by a piece of card kept in movement, and
give another exposure. Now re-develope to the right
density, and you will find that while the landscape gains
in strength the clouds will become faintly apparent. The
picture can then be fixed and finished according to the
If several copies of an enlargement are required, the
best method will be to make an enlarged negative on
paper, using a glass positive (an ordinary lantern slide) in
the lantern. The same operations as those just described
are necessary, but the exposure can with advantage be
increased. I should also recommend the use of alkaline
development, and I think that washing soda and pyro is
the best form of it for the purpose. The paper negative
when dry is rendered transparent by being passed through
a bath of melted paraffin wax. It can then be used in
an ordinary ' printing- frame to produce prints as may be
Some time ago I published a new method of obtaining
enlarged negatives, which will' be useful to those who wish
to work with an ordinary lantern, and who are ready to
undertake the task of plate-making.
THE BOOK OF THE LANTERN. 235
1 had occasion to obtain from some half-plate negativss
some copies of them on plates measuring 16 by 13. The
problem I put to myself was this, which is the quickest
and best way of accomplishing the work ? After some
consideration I determined to work with the limelight,
for the weather was dull and uncertain at the time I am
speaking of, and 1 thought that I would at once eliminate
one common source of error by adopting a mode of illumi-
nation which represents a constant quantity. This being
settled, I next thought over the different systems of en-
larging, and finally decided to try a new plan.
I am so constantly using the lime-light for lecture
purposes, that a residue of oxygen is always at hand,
ready for any home experiment that I like to try ; other-
wise, I should, perhaps, have decided to carry out my plan
with some other illuminant. Fitting a blow-through lime-
jet to an experimental lantern with a 4-inch condenser,
and with a quarter-plate portrait lens as the objective, my
optical arrangements were complete. But a 4-inch con-
denser is clearly useless for projecting the image of a
negative nearly double its area. My first operation was,
therefore, to make some small positives on glass from the
negatives. This was easily done by fitting the negatives
into my copying apparatus, and using a quarter-plate
camera. The size of the resulting positives was just two
inches across ; smaller, it may be thought, than was abso-
lutely necessary. But, by this plan, I employed the best
part of the projecting lens, and there was no chance of any
falling off in sharpness at the margin of the pictures.
The small positives were made with very great care, the
236 THE BOOK OF THE LANTERN.
exposure and development being so controlled that the
resulting pictures were somewhat denser than would be
advisable for an ordinary lantern-slide. They exhibited in
miniature every detail to be found in the negatives to
which they owed their origin ; and, in more than one case,
an improvement was effected in the process of reduction,
for some of the negatives were yellowed in certain portions,
and would, therefore, print unequally. This was obviated
by shading during exposure.
The positives, although measuring only 2 inches across,
were taken for convenience on the standard plates for
lantern pictures, 3 J by 3 J ; so that a broad margin of
clear glass remained all round them. This was covered
with black varnish, after which the glasses were fitted into
the usual grooved carriers employed in lantern work.
The next thing was to arrange a proper focussing-screen
for the reception of the image. This took the form of a
sheet of glass, 16 by 13, covered on one side with white
paper. Temporary wooden clips, fastened to the wall at a
convenient height from the ground, held this papered glass
in position, and in such a way that it could be readily re-
moved and a sensitive plate put in its place.
It is with regard to the sensitive plates that I must now
speak. I found that commercial plates of the size required,
16 by 13, were very expensive; if I remember rightly, some-
thing like .2 per dozen was the price quoted to me. This
was more than I cared to expend on mere experimental
work ; besides which, it goes against the grain to buy
plates when one has been in the habit for years of making
them of unsurpassed quality. I now bethought me that I
THE BOOK OF THE LANTERN. 237
had put away somewhere a jar of chloride emulsion, which
I had made some months before, and had left neglected for
want of opportunity to make plates from it. Why, thought
I, should I not make some 16 by 13 plates with this
chloride emulsion ? The thing was no sooner conceived
than put in practice, and that night the plates were coated
and racked, to the number of eighteen. I also was careful
at the same time to cover a few quarter-plates, with which
I could make trial exposures.
There is one great advantage in manipulating chloride
emulsion and the plates made from it : it is so insensitive
about 100 times less so than bromide plates that the
brightest of yellow lights can be used without affecting it.
I use a brilliant paraffin lamp, surrounded by a wire fence,
and this is covered with a screen of yellow oiled paper.
The light given is so great that a book can easily be read
at the further end of the room, and my coating-room is
quite a large one.
Two days later I was ready for work, and had the
lantern adjusted at the right distance from my focussing-
screen on the wall to give an image of the required size.
Carefully focussing the first picture, I took one of the
little trial-plates, and held it against the focussing- screen
for one minute. Upon development it showed under-
exposure. One or two more trials resulted in my finding
that the correct exposure was ninety-five seconds. I now
felt some confidence in dealin^ with the larger plates, and
I exposed three, one after another.
Now came the development. 1 mixed, first of all, one
pint of developer from my stock solutions, and this I put
238 THE BOOK OF THE LANTERN.
into a jug. The first plate was pat into a dish, and the
whole jugful swished over it. The image flashed out at once.
This is always the case with my chloride plates, so that it
did not surprise me. Keeping the developer moving over
the plate, I lifted up the glass at intervals so as to watch
its progress. In about four minutes it had attained
sufficient density. I then emptied the developer back into
the jug, for I knew it would serve for several plates in
succession. The negative in the dish was now thoroughly
washed with about a gallon of water, and transferred to
the fixing-bath. The remaining plates were then treated
in exactly the same way, and without a single failure.
There was at first some difficulty in thoroughly washing
such large plates, but I solved it by making use of the
bath-room. The bath was filled with water, and the
plates were placed along the sides, film-side down. In less
than an hour they were thoroughly freed of the fixing salt.
These negatives were all that could be desired. Some
of them were purposely reversed for printing by the
carbon process, this reversal being brought about by the
simple expedient of causing the film-side of the little
positive to face the light in the lantern. Their perfection
of detail may be gauged by the following : In one case the
little positive had become rather dusty previously to
exposure, and I took it out of the lantern, and rubbed its
varnished surface with my handkerchief. This caused
some tiny scratches upon it, which were at the time quite
unnoticed ; but the scratches were clearly visible on the
enlarged negatives. They were, certainly, not thicker
than the finest spider's web, but still, there they were.
THE BOOK OF THE LANTERN.
I have already indicated how this work of enlarging
can be done with an ordinary optical lantern, so long as
the size of the negative is not above that of a lantern
slide. For larger negatives it is far better to use a proper
enlarging lantern of the type shown at fig. 60.
THE LANTERN MICROSCOPE AND THE OPAQUE. LANTERN.
|P to a recent date the so-called lantern micro
scope supplied by various dealers was but a toy,
having all the faults which it was possible to
imagine in an optical instrument. Moreover, it neces-
sitated the use of specially prepared objects of large size,
the wings of insects and the like. But latterly a good deal
of ingenuity has been expended on the instrument, and it
has been brought to great perfection. Objects as prepared
for the ordinary microscope can now be used for projection
in the lantern microscope, and this one change of the
conditions under which the instrument can be used points
to an improvement of no mean kind.
There are certain requirements to be looked for in a
really serviceable lantern microscope. The first of them is
good illumination. The most perfect form of limelight jet
must therefore be used, and even this, when the higher
THE BOOK OF THE LANTERN. 241
powers of the instrument are employed, is far from being
enough. The electric light would obviously be the best
form of illuminant to use for the microscope, but the
incandescent variety is far too feeble, and the arc form
possesses neither the steadiness nor the accuracy and per-
manence of centreing which is so requisite in microscopic
work. So to the limelight we must at present confine our
attention, aiding it as far as possible by careful arrange-
ment of the lenses used in conjunction with it. Hence the
condenser must be of the best form, and must be seconded
by a substage condenser suited to the objective or power
which happens to be used. Provision must also be made
to filter the light through a layer of alum solution, which
absorbs the heat rays, and saves valuable objects from
Having secured the brightest light possible, and done
our best to concentrate it upon the object, we have
next to consider the best means of forming an image of
that object upon the screen. An objective may do excellent
work with the ordinary microscope, bat utterly fails to
give a satisfactory image on the lantern screen. Perhaps the
definition in the centre of the disc is satisfactory, but the
margins are all hazy and indistinct. One may examine a
large number of objectives with the lantern microscope before
one is found suited to the work. But makers are now
giving serious attention to the requirements of the recently
perfected instrument, and objectives of great excellence
can be obtained.
One of the most perfect as well as simple arrangements
for showing microscopic objects with the ordinary lantern
THE BOOK OF THE LANTERN.
is the attachment shown at fig. 61. This contrivance
may be compared to an ordinary microscope with its tube
removed, and with the lantern light at the back of the
stage instead of the mirror. The attachment is fixed
on the lantern in place of the usual objective, and the
objects to be shown are supported in a vertical position by
spring clips. The microscope objective is held, as shown,
on a movable arm worked to and fro by a milled headed
focussing screw. At the back of the object is a substage
condenser, not shown in the cut, and a revolving plate
with different sized diaphragms. A trough containing a
saturated solution of alum is placed on the lantern stage
to protect the objectives from heat. In using the instru-
ment the limelight must be adjusted in distance from the
condensing lens for each different power used; and, indeed,
for every change in the diameter of the diaphragm
employed. For living objects, such as those illustrating
pond life, a small tank is used, and is placed against
the spring clips. The objectives suitable for this form
of instrument are those which range between 3 in.
THE BOOK OF THE LANTERN.
and 4-10ths of an inch. Its performance leaves little to be
A far more elaborate form of lantern microscope is that
which is shown at fig. 62, and which has been designed
by Mr. Lewis Wright. In the opinion of most of our
eminent microscopists, including Dr. Dallinger and the late
Dr. Carpenter, this instrument is by far the most perfect
of the kind ever produced. It is certain that no better
effects are possible than are produced with high-power
objectives with this microscope, until the electric light
may be so perfected as to place a new power in our hands.
A flea 15 feet long, literally larger than an elephant, is
shown with this microscope brilliantly and exquisitely
defined, while the circulation of the blood in a frog's foot
can be as easily seen as by the table microscope.
244 THE BOOK OF THE LANTERN.
The instrument can be made either complete in itself, as
shown in the cut, or it can be fitted to any good optical
lantern. In the first case, it is provided with a triple 5-in.
condenser, which insures the maximum amount of light,
and in the latter case the lantern condenser, of whatever
form it may happen to be, is brought into use. The
illustration gives a very fair idea of this instrument, by
which the relation of its various parts can be well under-
stood. It has a coarse adjustment focussing screw, as
well as one for fine adjustment. The tube in front of the
objective is for the reception of various lenses to give
extra amplification, and the necessary alum-tank is let
into the brass front tube, midway between its supporting
pillar and the large condensers. The details of the stage
and revolving diaphragm plate are much the same as in
the instrument last described, but the substage condensers
are 'of varying foci, and are suited to the different objec-
tives employed. The milled head immediately above the
pillar is in connection with a rack tube, which provides the
necessary distance adjustment for these condensers.
THE OPAQUE LANTERN.
It will be at once conceded that most objects, animate
and inanimate, can be photographed, and that such photo-
graphs can be used as lantern pictures. But there are
still others which cannot be so treated, or rather, which
can be better shown as opaque objects. The worker with
the microscope will be able to appreciate the possibility
of showing, by means of the lantern, objects which are
not transparent. Some of the most beautiful effects
THE BOOK OF THE LANTERN. 245
seen in the microscope are by means of opaque objects
viewed by means of the spot lens. In like manner we
can obtain wonderful effects by the use of the opaque lan-
tern. Let me give one or two examples of the use of such
an instrument. Suppose that a lecture upon the history
and construction of the watch is contemplated. How dull
such a lecture would be if illustrated merely by a set of
diagrams ! The audience would soon be lost in the maze
of toothed wheels and springs, and few would understand
the difference between one movement and another. But let
the same lecture be illustrated by watches in action, their
enlarged images thrown on the screen, and their wheels all
at work, and how differently will the audience regard the
subject before them. Every tiny screw, the brilliant blue
of the steel parts, the very grain of the metal is beauti-
fully shown, while the ceaseless and silent working of the
mechanism adds greatly to the picture. Coins and medals
can also be splendidly shown by the same apparatus, and'
far better than in any other way. Various fruits can be
shown in section ; a lemon or orange so treated being a very
curious object, especially if it be squeezed, when the pips
and juice fly upward, or, at any rate, appear to do so. A
freshly-opened oyster makes another peculiar object for
the opaque lantern. These few examples will show that
this form of lantern is one which can be of great use in
intelligent hands. It is especially serviceable to the
owners of cabinets or collections of curiosities, moths and
butterflies, coins, medals, shells, minerals, &c., which
cannot readily be photographed, or which it is desirable to
show with their natural colouring.
246 THE BOOK OF THE LANTERN.
The opaque lantern was first devised by Chadburn, and
for a long time was known by his name. Its construction
is simple enough. The object is so placed that it can be
strongly illuminated by the condensed rays from either
one or two limelights ; an objec-
tive lens being used to form the
image on the distant screen.
The annexed diagram, fig. 63,
will explain the relations of the
different parts of a good opaque
lantern. LL are the limelights,
CC the condensers, O the ob-
jective, and E the object to be
shown. At one time, a large instrument of this type was
made for casting the image of a human face on the screen,
the lenses being of immense size. I saw this instrument
at work more than once, but its effect was most dis-
appointing. It certainly was not worth the trouble and
expense incurred in its construction. It was, of course,
fitted with a reversing lens, so that the face should appear
the right way up. The owner of this face, by the way,
suffered tortures during the short time of exhibition, for
the powerful limelights close to, and on each side of his
head, were so hot that they blistered his skin. He was
made to smile at the audience, and then to drink their
good health in a glass of wine, a refreshment which the
poor man really needed after his grilling.
Under the name of Aphengescope a contrivance is now
made for fitting on to the ordinary form of lantern, thus
dispensing with the cost of extra lenses. With a lantern
THE BOOK OF THE LANTERN.
thus fitted ordinary carte de visite portraits can be shown,
as well as the objects already enumerated. Fig. 64 shows
a modified form of aphengescope fitted to a lantern which
at the same time is ready to show slides in the ordinary
THE BOOK OF THE LANTETN.
manner. It will be noticed that behind the objective is
placed a sloping mirror, which reflects the light upon the
card, photograph, or other object above it. The objective
is then shifted from its usual position to an orifice above,
which is shown in the cut with a stopper in it. This
lantern the design of Laverne & Co. is lighted by a
mineral oil-lamp, but, obviously, the limelight could be
adapted to it. Mr. Medland, of the Borough, has intro-
duced a lantern on the same principle, see fig. 65. So much
light is necessarily absorbed by the arrangements of the
opaque lantern, even in its best forms, that the brightest
of illuminants must be secured to give it full effect.
It is on record that some years back a form of opaque
THE BOOK OF THE LANTERN.
lantern was used in an American Law Court to demon-
strate to a jury the manner in which a document had been
tampered with by a forger. Illuminated by a strong side
light, the magnified image showed clearly where the tex-
ture of the paper had been disturbed, both by erasure and
by the action of chemicals.
LANTERN, as supplied by the dealers, is with-
out any means of holding the slides during
exhibition. The slide stage is there, but it is
about 4J inches in height, while the slides themselves
are 3^ inches square. To obviate this difficulty, it
becomes necessary to fit this stage with a wooden
contrivance called a slide carrier, which can be pur-
chased of many different patterns. Professional exhi-
bitors use a wooden frame for each separate slide, but
this plan is both inconvenient and unnecessary for the
amateur. Besides which it is positively a bad plan for the
user of a single lantern ; for as each picture is removed,
and another one put in its place, the screen is left bare
while the transfer is effected. This not only has a bad
THE BOOK OF THE LANTERN. 251
effect, but it is distracting to the audience. Moreover, the
pictures suffer, for they compare disadvantageously
with the far brighter white disc by which they are
I can recommend two forms of carrier which obviate
this difficulty. The first is a grooved frame, open at either
side, with a travelling tape in the lower groove, which is
put in motion by a winch handle. The slides move
through the lantern one after another, like a panorama,
but care must be taken that they are not allowed to fall
out and get broken as their time for exhibition expires.
The other form which I recommend is quite different in
principle, and of the two methods I prefer it. In this
latter carrier there is a kind of central frame which
is accurately adjusted to the lantern stage. Within it,
and moving freely from right to left, is a double carrier,
holding two pictures side by side. While one picture
is being shown, the other is being changed, the right
and left hand carrier being used alternately. The sole
objection to this form of carrier is the necessity for
the exhibitor to reach over his lantern so as to change
every other picture, which is a slightly awkward thing to
A modification of this sliding principle, which consists
of a double changing stage, working vertically, has been
introduced, but I fancy that the lantern must be con-
structed purposely for it. I mean that it is not sold as an
independent carrier, which can be fitted to any existing
lantern. This consideration, of course, greatly limits its
252 THE BOOK OF THE LANTERN.
Whiting's patent arrangement for facilitating the ex-
hibition of slides is extremely ingenious, but seems to me
to be an adaptation of Samuels' changing box, for photo-
graphic cameras. At any rate, the same principle is
involved. It consists of a pusher of wood working be-
tween grooves on the lantern stage. Close against it is a
box of slides with a powerful spring at the back of them,
so that they are forced up against the pusher, the front
one being always in the right position to be pushed for-
ward on to the stage. The act of moving the pusher
sends a picture on to the stage, removes that previously
shown, which goes into another box, or drops down an
inclined plane out of the way, and at the same time the
lens is covered so that there is momentary darkness on
the sheet. This darkness is, I think, preferable, and less
trying to the eyes of the audience than if the actual
change of picture took place visibly.
Other forms of carriers provide in a different manner
for the lens being covered at the moment of change. One
very good one consists of a pair of wings, which open and
close automatically over the front of the objective lens
as the change is made. In this case the first picture
seems to darken down on the screen towards the centre,
'the reverse action immediately discovering the next
The following remarks, which were written by me, and
were published in the Yearbook of J ^ holography -, will
describe the kind of carrier which I myself use : " When
a man is in the habit of travelling about from place to
place on lecturing intent, he will, if wise, reduce his
THE BOOK OF THE LANTERN. 253
.impedimenta in the shape of lantern and lantern belongings
to the smallest possible bulk consistent with efficient work.
As much of my time has been and is spent in this way,
I have given a great deal of thought to this matter of
reduction of bulk, aud have achieved some little success in
it. But it is only to one particular point that I now wish
to draw attention, and I do so in the hope that what I have
done may be as useful to others as it has been to me. In
the first place I think that all lecturers will agree that each
lantern picture should be fitted in a carrier of its own. The
various forms of panoramic and shifting carriers which are
fixed in the lantern while the glass pictures are passed
through them at the time of exhibition are all very well
for home use and private work, but in my opinion are not
suitable for employment in public halls. I need not name
all my objections to them, for one will suffice. The
pictures are not sufficiently protected from breakage, and
the risk of breakage, even of one slide out of a set, is a
thing not to be thought of by a good exhibitor. At first I
used 7 by 4 mahogany-grooved carriers for all my pictures,
but I found that they were objectionable, on two grounds :
one of these is that they readily break, and the other is
that in packing they take up far too much room. It was
to obviate these difficulties that I designed the carrier now
to be described, and which I have had in constant use for
three years with every success. My only objection to it is
the necessity for making it myself, which is perhaps no
real objection at all, for a little carpentry forms a healthy
relaxation to one whose occupations are chiefly of a seden-
THE BOOK OP THE LANTERN.
My slide-carrier consists of a piece of wood 7 inches long
and 4 inches wide, with a square opening in the centre to
receive the glass picture of the standard size, 3^ by 3 J
inches. This is faced on each side with a piece of card-
board, the opening of which is so much smaller as to form
a rebate in which the picture rests, and from which it
cannot fall out.
And now to describe the method of manufacture. First
procure two pieces of sheet zinc, each measuring 7 by 4 inches
outside, but having openings of slightly different areas.
These are indicated in the annexed cut (fig. 66), the opening
- *7J *
in one piece of zinc being shown by unbroken lines, and in
the other by dotted lines. It is best to make these patterns,
in the first instance, in thin card, and to hand them to a good
workman to copy in zinc. (I may mention in parenthesis
that here I found my chief difficulty. The average British
working man who has been brought up in the zinc industry
THE BOOK OF THE LANTERN. 255
can make a first-rate chimney-pot, but when out of the
chimney-pot groove he is rather at sea. If he tells you that he
can cut out in zinc your pattern correctly, " Trust him not,
he's fooling thee " ; at any rate, carefully check his work, and
you may find it out a trifle, and this trifle when magnified
in the lantern is no trifle.) With correctly-cut zinc patterns
you can get through the work of making carriers very
quickly. The pattern with the larger opening may be
labelled W, for it is for wood only, and the other labelled
C, for cardboard.
The wood to use is the best pine, which in thickness
should approximate to the average lantern slide, say one-
eighth of an inch. This can be obtained at any good saw-
mills. Laying the zinc pattern on this, and pencilling
by its aid, a whole board can be quickly marked out for
cutting. This cutting can be easily accomplished by using
a sharp shoemaker's knife. The cardboard can be of the
thinnest description, and this, too, can be cut in the same
manner, using the zinc pattern designed for it. With
several wooden pieces ready cut, and double their number
of cards, you may now proceed to put them together. With
good hot, but thin glue, paint over one surface of the wood,
and press one of the cards upon it, taking care that the
centres of the two agree. Place the joined pieces on your
work-table, with a heavy, flat weight above them ; when
No. 2 is similarly treated, place it also under the weight, until
you have a goodly pile of pieces of wood faced on one side
with card. Leave them for the night. The next opera-
tion is to place a glass picture in each half -formed slide,
and to glue the cardboard face to each. Once more the
256 THE BOOK OF THE LANTEKN.
hot glue and weight operation must be repeated, until the
batch, say two dozen slides, is complete. When com-
plete, this batch, with a piece of blank board at each end
of the pile, may be screwed up between a couple of car-
penter's cramps, and left before the kitchen fire all day or
all night, until the glue is thoroughly hardened. When
quite dry and hard the slides may be separated and again
arranged between the cramps, in such a position that their
edges can be run over with a sharp plane. After this they
can be separately rubbed on every edge with glass paper,
and, when dusted, they are finished.
The advantages of these carriers are many. Firstly,
you may drop one from a height of 6 feet from the floor
with absolute impunity. Secondly, if the zinc patterns
be correctly cut, the slides will register correctly with one
another. Thirdly, six dozen, which is about the usual
complement for a lecture set, will pack in the space
occupied by three dozen under the old system. The sole
disadvantage pertaining to these carriers is, that the pic-
tures cannot be readily shifted from one to another. The
remedy is obvious. For lectures of an ephemeral cha-
racter, I mean for those the subject of which is merely
of passing interest, use the old form of carrier, but for ,
more permanent ones adopt mine.
It is given to a few to know what it is to arrive at a
schoolroom or other lecture-hall in some remote country
district, and to expect to find a few conveniences ready to
hand. The first thing to ask for is a table, upon which
THE BOOK OF THE LANTERN. 257
can be placed the lantern-box, while the lantern itself com-
monly screws to the top of the said box. There is always
a difficulty in finding the right kind of table. It is either
too small or too large, or else it is rickety and unsafe, or
perhaps it is too beautiful to be devoted to such a heathen-
ish purpose as the support of a lantern-box, all which
things happened to me and my assistant times out of
number, until I invented a lantern-support for myself,
consisting of four iron legs. With them> I can now laugh
the decrepit local table to scorn, and the beauty of the
leather-covered library specimen, which must not be
touched by sacrilegious hands, is a thing which ceases to
interest me. In a word, I am independent of such primi-
tive supports, and am as proud of my iron legs as is a
Chelsea pensioner of the wooden understandings which he
exchanged in the Crimea for those with which he was
The accompanying sketches will in a moment cause the
form and purpose of these legs to be understood. They
are made of iron, having a sectional area of 1 inch by
three-eighths of an inch. Each fits into a socket upon the
lantern box, and each has at its lower end a kind of flat
toe turned outwards, through which is a hole by which
the leg can be screwed to the floor. This, however, is
hardly necessary, for the weight of the lantern and its
box, together with the slides which it contains whilst in
use, are quite sufficient to make the whole arrangement as
firm as a rock.
In the annexed cut (fig, 67) A is the lantern box, fitted with
a strong frame at the bottom, F, upon which the sockets can
THE BOOK OF THE LANTERN.
be screwed. L is one of the legs in position. T is an
enlarged view of the toe of one leg, showing the screw-
hole where it can be attached to the floor. A 1 is a socket,
showing how it is composed of two pieces of iron, one flat
and one bent. I may mention that the top of the leg,
which fits into the socket, is diminished in size for that
purpose, and that the shoulder thus formed on it holds it
firmly in position. I have used these legs for several
years, and have never seen anything which would fulfil
their purpose so well. They can be secured for travelling
by a couple of leather straps, or can be made to go inside
the lantern-box. Their combined weight is fourteen
THE BOOK 'OF THE LANTERN, 259
Photographic negatives for lantern slides should be
rather less dense than those used for ordinary printing
upon paper : hence it is better to take negatives for the
purpose than to utilise others which have been taken for
ordinary reproduction. The lesser density must be gained
by stopping the development judiciously, and not, of
course, by checking the exposure. There are many
cameras now to be had which take small negatives suitable
for lantern work. These are so compact and self-contained
that they require no stand, focussing-cloth,, or other adjunct,
and will readily pack away in a portmanteau or box
without inconvenience to the traveller. The author has
used a camera of this description with great advantage, and
has taken many dozens of instantaneous pictures with it.
A useful form of hand-camera introduced by the
Stereoscopic Company is here shown (see fig. 68),
260 THE BOOK OF THE LANTERN.
Another camera which is made purposely for lantern-
slide negative making has been recently introduced by
Messrs. Mayfield & Cobb. This will, when folded up, easily
go into the pocket, and is used like the last-described
whilst held in the hand (see fig. 69).
A great deal of attention has lately been aroused with
respect to so-called detective cameras. They would perhaps
be better described as concealed cameras, for there are many
reasons why they cannot, except by some happy conjunc-
tion of circumstances, be used in the detection of crime.
Their manufacture has certainly been brought to grea^
perfection, and a wonderful amount of ingenuity has been
displayed in their construction. From experience I can
speak most highly of the good pictures which can be pro-
duced by them. But one essential condition must not be
absent; such pictures want absolute sunshine. I give
three examples of these detective cameras. The first,
Watson's (fig. 68), is a leather-covered box, containing as
THE BOOK OF THE LANTERN.
will be seen by the dotted lines, a complete camera. This
camera can be focussed and manipulated altogether by
touching buttons on the outside of the box.
Next I notice Marion's Parcel Camera (fig. 71), which
is of different construction altogether. It consists of a
covered box, like a parcel, but this box forms the camera
with a lens in front concealed by a paper flap. The
illustration shws the appearance of the underside of the
box, with a slit at one end for the reception of the sensitive
plate and the instantaneous shutter apparatus at the other
end. The plate is contained in a bag of the shape shown
THE BOOK OF THE LANTERN.
at fig. 72, which locks on to the aperture in the bottom of
the box, when a plate has to be transferred from one
to the other. I have found both these cameras to work
The newest arrangement of the kind is the Kodak
Camera introduced by the Eastman Company (see fig. 72).
In this small box a hundred pictures can be taken by
the simplest possible movements. It contains a ribbon
of sensitive material, which is used panorama fashion
instead of glass plates.
I am convinced that there is a very great future before
these detective or concealed cameras. That they will pro-
duce negatives of first-class quality, I have proved again
THE BOOK OF THE LANTERN.
and again, and it is the thought that such negatives can be
so readily made to give lantern slides, or can be used for
enlarging purposes with the help of the lantern, which has
induced me to give this brief notice of them in my chapter
on lantern accessories.
PRACTICAL HINTS TO THOSE WHO EMPLOY THE LANTERN FOR
SCIENTIFIC DEMONSTRATION, OR FOR ENTERTAINMENTS IN
THE DRAWING-ROOM OR LECTURE-HALL.
j 1ST the foregoing pages I have endeavoured to
describe the best methods of manipulating the
lantern ; and I hope that I have done so in such
a manner as to enable all my readers readily to under-
stand the working of this beautiful instrument. I feel
convinced that if my * instructions are carefully followed
all will go well, at all events, in the apparatus depart-
ment. But the best instrument is no good unless the
lecturer be an efficient showman and speaker. Unfor-
tunately many essay the task of lecturing who are physi-,
cally unfit for it. There are many good-natured people in
the world who will undertake, very often for some charity,
to act as lecturer in a school-room, the slides being
borrowed from some optician with a printed lecture fitted
to them. This good-natured man will take up the work
without much thought or consideration, and the result is
too often a very bungling performance. A man may have
THE BOOK OF THE LANTERN. 265
a fund of knowledge, but lack the power of imparting it to
others. The fault is common enough in the pulpit, where
it is often the case that a clergyman who has won high
honours at the university, and as a reward for his scholar-
ship finds himself in due course incumbent of a living, is
an utterly incapable speaker, greatly to the distress of his
congregation. He can of course compile or write a good
sermon ; that is to say, a discourse which is carefully con-
structed and perfect as a specimen of written English ; but
when he gets into the pulpit he reads it out in such a
droning voice, and with such a lack of emphasis, that many
of the congregation dose off into peaceful slumber. Many
lecturers have the same want of ability, and it is this
circumstance that has had the effect more than any other
of prejudicing people against a lecture, as a thing which is
necessarily dull and the reverse of entertaining.
More than once it has fallen to my lot to lecture in some
hall which is strange to me, and on such an occasion 1 have
generally asked the hall-keeper if a large audience may be
reasonably looked for. The answer is too often something
like this : " Well, sir, the people hereabouts don't much
care for a lecture ; but last Saturday night the place was
crowded from floor to ceiling." " Dear me ! " is my answer,
" and who was the lecturer on that occasion ? " " Lor'
bless your soul, sir, it wasn't no lecture, it was niggers." I
leave my readers to imagine with what feelings I looked
forward to the pleasure of meeting my audience.
A lecture entertainment will fail sometimes owing to the
total incapacity of the speaker, to his bad articulation,
nervousness, lack of voice, or want of tact in dealing
266 THE BOOK OF THE LANTERN.
with the audience. Still more often failure is due to bad
arrangement of the matter which the lecturer has under-
taken to deliver. The remedy for this last fault is
obvious, namely, a course of training in the reading of
standard works. Some may perhaps think I am recom-
mending an old-fashioned book, when I name " Blair's
Lectures on Rhetoric," as a very valuable aid to the writer
and speaker. I would advise all beginners to write their
lectures and go over the matter again and again, before
trusting themselves on the platform ; and in constructing
the fabric of their discourse, let them remember that the
sentences should be as a rule shorter than if the words were
merely intended for the eye of a reader. A sentence con-
sisting of several lines without any full stop, although it
may pass in ordinary composition, is very tiresome to listen
to ; a most attentive audience will, by the time the verbose
paragraph ends, forget its opening, and the sense be
consequently lost. Again, in composing a lecture which
is illustrated by lantern pictures, care must be taken to so
arrange it that the pictures come in naturally, and are not
dragged in willy-nilly, as if they were in stock and must be
shown at any price. The views should be the best of their
kind, but must be altogether subservient to the text. If a
part of the subject is of such a nature that it may be likely*
to prove tedious to an audience, and audiences differ
amazingly in their receptive faculties, that part should
either be compressed, or it may be lightened by a good anec-
dote, or even by some illustration which will raise a laugh.
Such pictures introduced with circumspection are most
useful ; but the power of employing them should be used
THE BOOK OF THE LANTERN. 267
sparingly. Let the lecturer look upon them as the high-
lights of a work of art. The novice with a brush will daub
such high-lights on every projecting corner of the compo-
sition, until the beauty of the whole is lost in their glare ;
a true artist, on the other hand, will deftly put in a touch
here and another there, with the result that the whole work
is brightened and generally improved.
The grosser faults into which a novice in lecturing is
apt to fall are generally the result of simple inexperience
or carelessness. He should make it a golden rule that
whatever may occur he must not lose his temper. In the
ordinary affairs of life, the man who can control his temper
has always the best of an argument ; and still more so is
this the case on the platform (and on this platform, let
us remember that there are often some very trying inci-
dents to deal with, particularly amid the darkness of
lantern illustrations). I once found it very hard to control
both my sentences and my temper, when I became aware
that I was a target for some mischievous boy's pea-shooter;
but on politely addressing the unseen youth, and telling
him that I knew he was a very smalllooj, and that therefore
I could excuse his childish conduct, but at the same time he
must keep his peas in his pocket, the nuisance stopped. I
recently heard of a case where an inexperienced lecturer
was loudly told more than once to " speak up." Instead of
taking this invitation as a valuable hint, and acting upon
it as he should have done, he retorted rudely, and the audi-
ence refused to listen to him any longer. It is to be hoped
that he will not again attempt work for which he is
evidently quite unfitted.
268 THE BOOK OP THE LANTERN.
Iii lectures of a popular and entertaining character,
it is often desirable to introduce a little music; but if
this is done at all it should be done well, the lecturer first
of all satisfying himself as to the capabilities of the
musician. They should then arrange together where the
music is to come in, and the player should have furnished
to him by the lecturer a set of cues, with hints as to the
nature of the music to be played at the occurrence of those
particular words. To show that this precaution is not an
idle one, let me state that recently I heard a lecture de-
livered in which a few bars of music came in at stated
times. On one of those occasions the lecturer was showing
a tomb erected to the memory of some celebrity who had
recently departed. He described this tomb and said a few
touching words with reference to the high character of the
departed one ; and, he had no sooner finished, than the
pianist at his elbow struck up a merry waltz !
The lecturer should be careful to select an intelligent
operator. The man employed should be one capable of
concentrating his attention upon the work which he has
to do. The gases will require attention, the lime wants
turning every few minutes, or the light from the lantern
soon drops; but, at the same time, too much should
not be thrown upon the hands of the operator; for in-
stance, the lecturer should make it a standing rule to go
carefully through the slides which are to be shown before
the lecture commences, so that each one is not only in its
proper place, but each is so arranged that the operator will
hardly be able to put one in the lantern except in its right
position. A landscape, or more especially a portrait, ap-
THE BOOK OF THE LANTERN. 269
pearing suddenly on the sheet standing on its head, is an
episode which disturbs both lecturer and audience, and
will, for a time, entirely break the thread of the discourse.
This can easily be avoided if the slides be marked in a
certain way. If the slides are being used in fixed carriers,
and are therefore simply in the form in which they are sold
at the shops, each one should be marked with a white disc
at the lower left-hand corner of the picture, taking care
that the wafer is on the face of the picture, and by pre-
ference, beneath the cover glass, so that it cannot be rubbed
off. This white wafer will then come conveniently below the
operator's thumb when the slide is in its inverted position,
as it should be, before being placed in the lantern.
The operator will then become accustomed to look for this
white dot, which he can easily see even in a darkened
room, and he will place his thumb above it, and the picture
will of necessity appear on the sheet, as it should do. If
the back of the picture is placed next the light, of course
everything on the sheet appears in reversed order. What
should be the right hand of the picture appears on the left
of the sheet, and vice versa. This is of no great conse-
quence in some cases ; but if the picture should include
any lettering, such as that on a sign -post or a shop-front,
these letters will appear backwards, and the fault is at
once detected by the audience, and commented on by them
in audible whispers. I once had a volunteer assistant who,
at short notioe, supplied the place of my regular operator,
who happened to be ill. In the middle of my lecture this
man showed a slide upside down ; on seeing his mistake,
he took it out of the lantern and put it in again sideways.
THE BOOK OF THE LANTERN.
He again saw the error, took it out of the lantern, and re-
placed it, but on its other side ; so, in reality, this genius
tried every conceivable way of showing
that picture but the correct one.
It is imperative that there should be
some well-understood code of signals be-
tween the lecturer and the lantern operator,
for in many cases they are 50 feet apart.
Some lecturers are content with verbal
directions, but these are simply intoler-
able to any one with any idea of what
a lecture should be. To hear a man
calling out, " Next picture, please," and
so on, utterly spoils even a lecture which
is good in other respects. An audible
sound signal, such as tapping with a
pointer, or sounding a gong when the
picture is required to be changed is
almost as bad. A lecture lamp has
recently been introduced, which not only
comprises a shade light for the lecturer's
desk, but has at the back, i.e., the side
presented towards the audience, and there-
fore towards the lantern, a little disc of
red glass, which is uncovered by touching
a lever at the side of the lamp. See S,
fig. 74. When the operator sees the little red flame dis-
closed he knows that a fresh picture is wanted, and should
he be inattentive to that signal there is a little gong, B, below
the lamp which can be used on such an emergency. This
THE BOOK OF THE LANTEEN. 271
lamp is portable, convenient, and efficient. But above all
devices for signalling I prefer a simple electric arrange-
ment. The one that I am in the habit of using consists of
a single-stroke electric bell with the gong removed from it.
When the current is sent through the coils of the attached
magnet, the armature is of course attracted, and a little
tap is heard, which, although quite unnoticed by the
audience, is easily heard by the operator, who is on the
look out for it. I used to employ in connection with the
bell, if bell it can be called, a Leclanche battery which
was placed just below my reading-desk. While on the
desk itself I had an ordinary bell push, connected with
both bell and battery. But this arrangement I have since
superseded by a better one. The Equitable Telephone
Company have brought out an electric bell which is quite
independent of battery power, a small magnetic arrange-
ment taking its place. This generator, as it is called, is
shown at fig. 75. It acts most perfectly, and is destined,
I should presume, to work a revolution in electric bell
mechanism generally. The only inconvenience in the
arrangement is the difficulty that is sometimes found in
carrying the wires between the lecturer and the lantern,
and so concealing them or putting them out of reach
that there is no chance of their being tampered with by
mischievous hands. In a lecture theatre, where there is
commonly a gallery, the wires can be run round the
front of the balcony quite out of sight. In other cases
they can be laid on the floor underneath the carpet or
matting. In nine cases out of ten there is no difficulty
in adjusting them. The signal should be given about
272 THE BOOK OF THE LANTERN.
half a minute before the change of picture is really
required, 59 as to give the operator time for the necessary
manipulation. He should be instructed when to dissolve
the view slowly, should he be using a double or triple lan-
tern, and when to make the change quickly. To dissolve a
diagram or a portrait is ridiculous, and sometimes leads to
very comical effects. I remember once attending a lecture
where a number of illustrations were shown of different
types of national costumes. First of all there came a
woman in peasant's dress. This was followed by a man
whose lower extremities were clothed in tight-fitting white
unmentionables. It so happened that one figure occupied
on the screen exactly the same place as the other, so
THE BOOK OF THE LANTERN. 273
that when the lady was slowly dissolved into the gentle-
man, the astounding effect was produced of .her clothes
gradually melting from her form.
I must now bring my remarks to a conclusion, with
the hope that many will find my book useful. If the
word Ego has crept in with too much persistence, I trust
that my indulgent readers will impute it rather to personal
acquaintance with the things of which I write than to any
less worthy source.
ADVANTAGE of pure hydro-
Aniline colours, 161.
Astrometeoroscope, The, 180.
BELL, Electric, 271.
Biunial, Detachable, 13.
Biunial lantern, 8.
Blow-through jet, 53.
Boards, Double, 62.
Brass work, Superfluous, 10.
Brewster, Sir David, 5.
Brin's Oxygen method, 46.
CAMERAS, Detective, 260.
Camera for microscope, 215.
Cameras, Hand, 259.
Capacity of cylinders, 49.
Choreutoscope, The, 180.
Clamp, Steward's, 56.
Clouds, Printing, 233.
Cohesion figures, 175.
Collodio-bromide process 111.
Coloured gelatine, 188.
Colouring lantern slides, 145.
Colours, Complementary, 166,
Colours used for slide painting,
Complementary colours, 166,
Compound frame for copying,
Compressed oxygen, 48.
Condenser, Dallmeyer's, 23.
Copying apparatus, 124.
Copying paper prints, 121.
Current reverser, 173.
Cutting masks, 142.
Cylinders, Capacity of, 49.
Cylinders for gas, 48.
DALLMEYER'S Condenser, 23.
Decomposition of water, 192.
Desk for slide painting, 148.
Detachable biunial, 13.
Detective cameras, 260.
Developers, 120, 121.
Development of photograph in
Dissolver, 9, 80.
Distance between lantern and
Distances, Table of, 96.
Double boards, 62.
Drummond Light, 5.
Dry plate slides, 109.
EASEL for enlarging, 224.
Electric Bell, 271.
Emulsion, Filtering, 132.
Emulsion making, 128.
Enlarging lantern, 239.
Enlarging photographs, 222.
Equivalent focus, 95.
Ether-oxygen light, 83.
Experimental lantern, 190.
Experiments with tank, 193.
Exposing gauge, 229.
Exposures for enlargements,
FILTERING Emulsion, 132.
Frame for sheet, 93.
Frogs' legs, Projection of,
Gas bottles or cylinders, 48.
Gelatine process, 115.
Gelatino-bromide paper, 225.
Gelatino-chloride plates, 133.
Glass grinding, 101.
Ground-glass lantern slides,
Ground-glass varnish, 102.
Gauge for exposures, 229.
HAND Cameras, 259.
Hanging the sheet, 88.
Hints, Practical, 264.
Home-made gelatine plates,
Hydrogen generator, 69.
ICE experiment, 197.
Iceland Spa, 187.
JET, Blow-through, 53.
Jet, Mixed, 53.
Jet, Oxycalcium, 50.
KALEIDOTROPE, The, 179.
LAMP, Newton's, 6.
Lantern and Photography,
Lantern, Biunial, 8.
Lantern enlarging, 239.
Lantern enlargements, 209.
Lantern for experiments, 190.
Lantern, How to work, 76.
Lantern legs, 256.
Lantern microscope, 240.
Lantern, Mineral Oil, 7.
Lantern, Opaque, 244.
Lantern-slide colouring, 145.
Lantern - slides from paper
Lantern slides on dry plates,
Lantern-slides on ground
Lantern-slides on wet plates,
Lantern-slides with transferro-
type paper, 143.
Lantern, Triunial, 15.
Lecture -lamp, 270.
Lenses, Condensing, 21, 23.
Lenses, Objective, 26, 27.
Lens, Supplementary, 22.
Limes, Preserving, 74.
MAGNETIC experiments, 201.
Making emulsion, 128.
Making oxygen, 30.
Masks, Cutting, 142.
Micro, Attachment, 220, 242.
Microscope, Camera for, 215.
Microscope, Lantern, 240.
Mineral oil lantern, 7.
Mixed jet, 53.
Mixture, Oxygen, 40.
Moonlight pictures, 159.
NEWTON'S Lamp, 6.
OAKLEY'S regulator, 64.
Objective lenses, 26, 27.
Opaque lantern, 244.
Opaque lantern, principle
Optical system, 16.
Oxy calcium jet, 50.
Oxygen, Erin's method, 46.
Oxygen, Compressed, 48.
Oxygen-ether light, 83.
Oxygen making, 30.
Oxygen mixture, 40.
Oxygen retort, 32.
PAINTING with aniline colours,
Photographs, Enlarging, 222.
Portable frame, 93.
Practical hints, 264.
Preserving limes, 74.
Pressure boards, 60.
Primitive lime-light, 51.
Printing clouds, 233.
Prism, The, 182.
Pure hydrogen, Advantage of,
Purifier, or Wash-bottle, 37.
BACK, Washing, 136.
Regulator, Oakley's, 64.
Ketort, Oxygen, 32.
SAND - GLASS, Projection of,
Sheet, Hanging, 88
Short-focus lens, 138
Simple regulator, 68
Sir David Brewster, 5
Sky, Treatment of, 139
Slides by contact, 137
Spectrum slides, 186
Steward's clamp, 56
Steward's regulator, 68
Superfluous brasswork, 10
Supplementary lens, 22
Support for lantern, 256
TABLE of distances, 96
Tank experiments, 193
Tannin process, 110
The Astrometeoroscope, 180
The Choreutoscope, 180
The Galvanometer-slide, 171
The Kaleidotrope, 179
The Prism, 182
" Toilers of the Thames,"
Treatment of sky, 139
Triunial dissolver, 81, 82
Triunial lantern, 15
Tyndall's ice experiment, 197
USE of condenser, 18
VERTICAL attachment, 12
Vortex rings, 191
WASHBOTTLE, or purifier, 37
Water, Decomposition of, 192
Wet Collodion-slides, 104
Whitewashed screen, 91
Woodbury-type process, 113
Working the lantern, 76
J. H. STEWARD'S
MAGIC AND DISSOLVING VIEW
STEWABD'S PORTABLE TRIPLE LANTESN.
With all ihe Latest
POST - FREE.
OPTICIAN TO THE GOVERNMENT AND SCIENTIFIC COLLEGES
406-457, STRAND, & 54, CORNHILL, LONDON.
COLLODIO BROMIDE SUPERSEDED.
* ISSUE OF NEW SERIES. +
THOMAS'S PALL MALL
Lantern and Transparency
T> Y a peculiar and quite novel combination of the haloid salts of
*-* silver, we have produced in Gelatine an Emulsion which throws
all previous efforts in this direction into the shade, and is pro-
nounced by all who have tried it a perfect substitute for Collodio-
Bromide in Lantern and Window Transparency Work.
All Tones are easily obtainable, from a rich velvety black to a
For Micro-Photography, Copying, and Enlargements, it
is all that can be desired.
Prices, LANTERN PLATES, 3i by 3i, Is. per dozen.
All other sizes coated and charged at the Pall Mall
Pot or Flashed Opal, or a fine ground glass, coated to order at
R. W. THOMAS & CO.
1O, * PALL * MALL, * LONDON.
Factory Thornton Heath, Surrey,
MAGIC * LANTERNS
S 3LI 3D E S. *
iHY does WALTER TYLEB do the LARGEST BUSINESS,
and is enabled to make and sell Magic Lanterns and Slides Cheaper than
any other House in the Trade?
BECAUSE, making this business his Entire Occupation and Study, he is
able to produce the Best Magic Lanterns and Slides at such Moderate
Prices that other houses Cannot Compete.
LANTERNS AND SLIDES LENT ON HIBE.
Upwards of 8O,OOO always in stock.
7TTITHOUT DOUBT the Best and cheapest House in the World for everything
Vll connected with Magic Lanterns and Slides. Thonsands of Slides and
Lanterns Second-hand. Great Bargains. For good quality of Articles, moft
moderate Prices, and Promptness in Despatch, WALTER TYLER cannot be
surpassed. ^^^^^ _ ~^~~^~^-
Send for Illustrated Catalogues and Second-hand Lists, which
will be sent post free.
G. 8. MARTIN,
AND RETAIL DEALER IN
PERKEN, SON, & RAYMENT'S
OPTICAL LANTERNS. PHOTOGRAPHIC CAMERAS, LENSES, So,
SLIDES ON HIRE. 1/6 PER DOZEN.
MAGNESIQM FLASHER, for Night Photo-
_ graphy (or " Stage Lightning ") 4/6.
LANTERN TRANS PARFNCTES pr^rpd from Pictures, Drawings, Ac.
QPCTOTAf^l PQJ BREAM'S BUILDINGS,
Or C.O I r\v>L.CLO 1 LONDON, E.G.
(Under Sirkbeck Institution, approached by Ch'inrery-la>-e w FMer-lane).
FOR LANTERN J^HOTO GRAPH Y.
CHLORIDE AND BBOMXDB LA.NTBBW PLATES BY
HINTON'S PATENT FOLDIG PLATE RA.CKS, for Lantern Plates
HINTON'S PURE CHEMICALS and READY PREPARED SOL u I JONS.
gLNTON'S LAN TERw MASKS, BINDERS, PLATE BOXES, c.
INTON'S LANTEnN GLASS PLATES.
HINl'ON'S PHOTOGRAPHIC MATERIALS are used by the most
Successful and Advanced Photographers.
HINTON'S LANTERN CAMERA, with 12 double backs, Lens, Cloth Case,
and Stand complete. .Price 7-
HINT ON'S COLLEGE LANTERN, 4-inch condenser, 4. W ick lamp, best make
throughout. Is aoapted to take lime-light fittings. Price 3. 17s. 6d.
Note the Ad dress -38, BEDFORD STREET, STRAND, W.C.
Pharmaceutical, Operative, and Photographic Chemists.
PERKEN, SON, & RAYMENT *SSS*
Discounts (for the Trade ONLY)
and PHOTOGEAPHIC APPARATUS.
SIDE-BY-SiDE OR BI-UN1AL MAGIC LANTERN.
THE above diagram is a full-sized combined lantern.
^ It is made of japanned metal. It may be used
x^7~4w n-^k one ab jre the other, as the dotted lines show, or side
by side as the positive diagram shows t or, again, the
two instruments may be separated and worked in two
distinct places, as each lantern is complete in itself.
A further advantage is possessed by this lantern, for
the bodies, which are constructed to accommodate lime-
light, will alscj readily accommodate : oil-lamps, the
grooves into which the trays are inserted bciug made
I to the same gauge as our lamps.
" It will at once b<* seen this makes the apparatus &
most desirable one for those who let out on hire, since
it adapts itself 10 every variety of exhibition. The
price includes 4-inch Compound Condensers and
superior Portrait combination front lenses (which
give splendid marginal definition). We believe this form to be thoroughly
efficient, consequently strongly recommend it.
Without Lamps or Jets 5 ft O
3-wiek Lamps, each O 12. 9
Gas Jets O 11 O
" OPTIMUS' 5 TRIPLE DISSOLVING TAP
Free from complication, free from danger,
AT VERY REDUCED PRICES.
Superior Hand-Painted Magic Lantern SLIDES,
The productions of the eminent firm of
CARPENTER & WESTLEY, Regent St., London,
Who desire to reduce their exceptionally large stock, which has always ben
regarded as the first in the world for ARTISTIC MERIT, whilst for
Brilliancy and Transparency of Colour the pictures are unrivalled.
Every requisite for Magic Lantern at lowest possible
99, RATION GARDEN, LONDON, E.C,
FIVE PRIZE MEDALS HAVE BEEN AWARDED FOR
MAGIC + LANTERN + SLIDES
PHILIP H. FINCHAM,
MYTON RD., WEST DULWICH, LONDON, S.E.
Manufacturer & Publisher of Magic Lantern Slides & Readings.
Catalogues on application. Sample Slide and Catalogue for Is. 6d.
Silver Printing and Transparencies from the Negatives
The Lenses we hive designed for this purpose are the outcome of a long and
interesting experience of Lantern work. They hive a full aperture of f/4, and their
power of definition and flatness of field are excellent.
Approximate distance from
screen to cover.
12 ft. sq.
15 ft. sq.
20 ft. sq.
The Original Five-wick Lantern. For Opaque Objects, Carte-de-Visites, and Ordinary
Slides, without change of Apparatus. Arrangement in chimney to prevenc smoke
and regulate lamp.
The only Lantern which can be changed to exhibit Opaque
Objects in One Moment.
Price, complete in Strong Iron Case, 5.
Fwilparticula.r,v;ith:numerou*te*tin>onialg, .Tree. Medland'g Catalogues of Lanterns t
Transparencies, Photo. Goods, Microscopes, if Electric Apparatus, now ready.
LONDON BRIDGE, S.E.
J. BRANDON MEDLAND,
Is ttie smallest, lightest, and simplest
for the ten operations necessary with
we have ONLY THREE SIMPLE MOVEMENTS.
REQUIRED. Size 3^ by 3! by 6J inches.
of all Detective Cameras
most Cameras of this class
No FOCUSSING. No FINDER.
Weight 35 ounces*
Developing 12 at once. Drawing off Exposed Films.
Twelve Negatives are developed at one time.
NO TOUKIST OB CYCLIST SHOULD BE WITHOUT ONE.
FULL INFORMATION FURNISHED BY THE
EASTMAN DRY PLATE & FILM CO., 115, Oxford Street, London, W.
ARCHER & SONS
Have proved by Public Competition to be superior to all others.
Awarded Prize Medals, Liverpool International Exhibitioa, 1886, and
Photographic Exhibition, 1888.
THE "PHOTINUS" (REGISTERED) IS THE MOST POWERFUL OIL
LANTERN IN THE WORLD.
Full-Sized LAKTERNSlromliuuiEi to SIXTY POUNDS.
Manufacturers of SLIDES to the Wholesale
London Houses, &c.
PRICE LISTS WITH FULL PARTICULARS AND MANY
ARCHER Ei SONS, Lantern Specialists,
43, LORD STREET, LIVERPOOL.
Brin's Oxygen Gas, compressed in Cylinders.
Magic Lantern Slide and Dissolving 1 View Artist, Photographer
and Manufacturer of all kinds of Lantern Slides.
Designer and Producer of Mottoes, Curtains, Comics ; " The Seasons," " Funny
Faces with Moving Eyes ; " Skipping, Slipping, Photographic Effect Sets, and
Mechanical Slides. Also the celebrated set " The Village Blacksmith."
Transparencies produced from Drawings, Engravings, Ac., aud Customers' Own
> etfatives. Slide Colouring for the Trade and Private Customers. Special
Lecture Set* prepared, and Original Designs made. Hand-painted Slides to
order. Slides by all the best producers, and all the Latest Novelties in Stock.
Slide Carriers, Frames, &c.
CATALOGUE GRATIS AND POST FREE.
23a, Clarendon Rd. Croydon, Surrey, near London.
30 Interesting Sets, with Descriptive Lectures.
LIST FREE ON APPLICATION.
Slides made to order from any view in our General Catalogue. Over 10,000 subjects
to select from in England, Scotland, Wales, & Norway. Catalogues, post free, 6d.
Pbotograplrc Publishers, 152 and 154, Perth Road,
3D TJ 1ST IDEE.
New Enlarging Apparatus.
THIS APPAKATUS is designed specially for Amateurs, who, ot having
attempted enlarging before, require an Apparatus that is not only simple and
easy to work, but effective in results. The L. S. Co. feel sure that this
Apparatus will meet the above requirements better than any that have been pre-
viously designed, not only for completeness but for its extreme utility.
PRICES complete, with three-wick lamp, for giving a most brilliant and effec-
tive light, with tin case, encased in mahogany body with a sliding-camera front,
for adjusting to various sizes, fitted with one of the London Stereoscopic Company's
best portrait lenses, with rack and pinion adjustment. The whole of the above is
fitted into a box, with dishes, enlarging paper, chemicals of all sorts that are
necessary, together with the various et cat era ; the lantern is fitted with a splendid
5-in compound condenser. The above is the most complete and perfect Enlarging
Apparatus ever designed, and will give perfect satisfaction to our numerous amateur
and professional patrons.
Small size (5-inch condenser), price complete .10. 10s.
Larger size, for enlarging from half-plate negatives
(7-inch condenser), price complete .15. 15s.
A FREE DEMONSTRATION given to Purchasers of the above
Enlarging Apparatus at any time by appointment, at
110 AND 108. REGENT STREET, W.
And 54, CHEAPSIDE, B.C.
To Lecturers and Others using the Oxy-Hydric Light.
BRIN'S OXYGEN CO, Ltd, sappi,
And also Hydrogen, or Coal Gas, compressed in
portable vessels, at the following low prices:
Tested to 3,000 Ib. per square inch, and fitted with Brin's Oxygen
Company's Patent Value.
over all in
the first 14
Prices of Oxy-
gen or Hydro-
gen per cubic
In quantities of
20 ft. or less,
Over 20 ft. and
up to 60 ft.
In quantities of
60 it. 2d.
FITTINGS : Nipple and Union, 2s. 3d. ; Key, 2s. 9d.
TERMS: Net, cash with order.
Deposits : Customers not wishing to purchase cylinders, must
send with their order an amount equal to the price of cylinder and
fittings, as a deposit ; and on all cylinders not returned within 14
days, rent will be charged as specified above.
ERIK'S OXYGEN COMPANY, Ltd.
VICTORIA ST., WESTMINSTER, S.W.
(Works, 69, Horseferry Koad, Westminster, S.W.)
la the Best Photographic Plate made for the production of
Transparencies and Slides for the Optical Lantern.
The effects produced on these plates cannot be surpassed for
delicacy and brilliancy.
The Developing Formula is simple, handy, and cleanly, and
will meet with special welcome from Amateurs.
Instructions accompany each Box.
SIZE 3jx3J 4|x3| 5x4 6x3J 6x4| 6|x4f 7|x4 7x5
Prdoz 1/4 1/9 2/3 2/6 3/- 3/6 4/- 4/tt
SIZE 7^x5 8x5 8^x6^ 9x7 10x8 11x9 12x10 15x18
Per doz 5/- 5/6 6/6 9/- 12/- 14/6 16/- 281-
J. HASWELL, Esq., Sunderland.
"'The Amateur Photographer' Silver Medal has been
awarded to me for the transparencies which I exhibited. They
were ail done with your ' Lantern ' Plate."
B. G. WILKINSON, Esq., Streatham Hill, S.W.
" I am pleased to tell you that, at the Liverpool Photo. Exhibition,
1888, 1 was awarded a Silver Medal for Lantern Slides, which
were made upon your Mawson Lantern Plates. I consider your
plates excellent in every way."
The EDITOR of "THE CAMERA."
" The specimens of Lantern Slides treated with different developers
are singularly fine."
The EDITOR of the "AMATEUR PHOTO-
"In our hands we have always found good results from their
plates, and the Lantern Plate is unequalled in the market."
MAWSON & SWAN. 33, Soho-squire, London.
AWARDED TWO CERTIFICATES, CRYSTAL PALACE EXHIBITION, 1888.
Messrs. D. NOAKES & SON
Would call the special attention of Lecturers, Users,
and Intending Purchasers of
To the PRACTICAL SUPERIORITY of the Apparatus they Manufacture.
The whole of the Improvements adopted by
MESSBS. NOAKES & Sox have been suggested
by a long practical experience, Mr. C. W. LOCXB
and Mr. D. W. NOAKBS, two of the Principals
of the Firm, having personally operated at
upwards of 5,000 Exhibitions.
MESSES. NOAKES & Sow would also call the
attention of Lecturers and others to their Im-
proved Method of COBBBCTING BI-UNIAL and
TBIPLE LAKTEBNS, by which PERFECT BEGIS-
TEATION of the most complicated effects can be
secured at every and any distance from the
screen. Special attention is also called to the
HOAXES' PATENT TRIPLE DISSOLVED
without which no Triple is complete.
Mr. LEWIS WEIGHT, writing in the Sritinh
Journal of Photography, March 9th, 1888, says :
" Another ' mistake ' exhibited was a telescopic
front with rack and pinion to every ' draw ! '
Again, this is mere useless expense and unprac-
tical ..... We do not want in a lantern any
.mechanism that is not of distinct use, but
Ppractical simplicity, with no more weight and
size than are needed. Mr. Noakes showed
how, by the ' loose jacket ' now coming into use among those houses which really
have the largest experience, a lantern with only the single ' draw ' usual on all can
have a * range ' of focus of seven inches between greatest and least. . . . This tap
is a really good thing, as is the triple ' dissolver ' of Noabes. By ranging two sets
of holes on one spindle, this tap dissolves any pair of lanterns, or puts on any
single; and by separating the 'setting' and 'dissolving' levers this is done with
absolute certainty and simplicity in the dark, while bye-passes can be arranged
NOTICE. Mr. D. W. Noakes and Mr. C. W. Locke personally
give Lessons in Operating.
Full Particulars and Catalogues, post free, from
3D. JSTO^IKIIES <Sc SOICT.,
Inventors, Patentees, and Makers of
Improved Magic Lanterns, Dissolving View, Lime Light Apparatus and
Slides, Photographic Lenses, Cameras, etc.
BILLINGSGATE STREET, GREENWICH, LONDON, S.E.
TELEPHONE, 8029. HOURS, 9 to 6.
ALL work being done on the premises, Repairs and Alterations can
~be executed on the shortest notice.
PHOTOGRAPHIC TRANSPARENCIES MADE TO ORDER. LIBERAL TERMS TO THE TRADE.
ON SALE OR HIRE,
NEW SETS OF SLIDES.-Architecture-Lifeboat
Services Types and Anti-types of our Lord Spanish.
Armada English Church History Rise of Nonconformity
Botany The Great Ice Age Food Adulteration The Bngadine
The Riviera Berlin Rise of English Literature Tales from
Life-Models, and 60/00 other S'ides in stock before.
The "EUPHANERON " LANTERN, with the Four-wick
W Lamp, 4. 4s.
Tne "CHEAP" LANTERN, with 4-in. Condenser and
Three-wick Lamp, 1. 15s.
WOOD'S NEW LIST OF SLIDES AND LANTERNS. POST-FREE FOR ONE STAMP.
^ WOOERS *+
WOOD'S NONPAREIL SET FOB PICTURES
4^ by 3t, complete with chemicals, &c., in case 2 15
WOOD'S INSTANTANEOUS SET FOR PICTURES
44 by 3$, complete with chemicals, in case 5
WOOD'S INSTANTANEOUS SET POR PICTURES
6 by 4f, complete with chemicals, in case 8 12
" A PHOTOGRAPH, AND HOW TO TAKE IT," together with
complete list of Photographic Apparatus. Post-free One Stamp.
E. G. WOOD, 74, Cheapside, London; and
HORNE, THORNTHWAITE, & WOOD, 416, STRAND, LONDON
TO HER MAJESTY'S SCIENTIFIC
. GOVERNMENT DEPARTMENTS.
SEVEW GOLD MEDALS AWABDED.
LIST OF PHOTOGRAPHIC LENSES.
PORTRAIT LENSES. PORTABLE PARAGON LENSES,
LANDSCAPES, ARCHITECTURE, AND
No. 1 for Portraits 61 by 4| .... 1515
2 81 61 .... 24 6
,,3 10 8 .... 35 4
4 18 16 .... 38 5
5 22 18 .... 49 12
No. 1 for Cabinets, 14 ft. distance.. 11 14
2 .. 18 ft. .. 15 15
3 ,. 20 ft 17 11
No. 1 for Cards .. 14 ft. distance.. 5 10
,,2 .. 16 ft. ..660
3 .. 19 ft. .. 10 3
Invaluable for Photographing Children.
No. 1. 41 in. focus, diani. 2J in. .. 12 3
,. 2,6 in. focus, diam. 31 in. .. 22 10
UNIVERSAL PARAGON LENSES,
PORTRAITS, GROUPS, STUDIES IN
STUDIO, & PANEL PICTURES.
WIDE-ANGLE LANDSCAPE LENSES.
Working Aperture, U.S. No. 4, F/8.
5 by 4
10 , 8
12 , 10
15 , 12
18 , 16
22 , 20
3 by 3
4 by 3
5 by 4
5 , 4
2 18 6
8 , 5"
9 , 7
10 , 8
12 , 10
15 ,, 12
18 ,, 16
22 ,, 18
RAPID PARAGON LENSES,
GROUPS, VIEWS, INTERIORS, AND
4 by 3
4 14 6
5 17 6
24 i25 ,
41 .. 38
WIDE-ANGLE PARAGON LENSEo.
Giving 100 of angle for Photographing
Largest Dia. of
71 by 41
3| ., i!7
Iris Diaphragm fitted to above Lenses. For Price, &c., send for List.
THE ABOVE PRICES ARE SUBJECT TO TEN PER CENT. FOR CASH WITH ORDER.
University Optical Works, 81, Tottenham Ct, IL1
OPTICAL PROJECTION and
<* SPECTRUM WORK.
AS MADE FOB OXFORD AND OTHER UNIVEB8ITIES.
SINGLE, DOUBLE, AND TRIPLE.
Optical * Lanterns
and APPAEATUS for PEOJECTION of
every descrittion and of the highest
quality, as supplied to the Science and
Art Department and all the principal Uni-
versities at home and abroad.
Slides of Every Subject.
Of the Best Quality only, made from
customers' Negatives or Sketches at
ENLARGING * LANTERNS,
3 in. to 15 in.
AS MADE FOB THE POLYTECHNIC SCHOOL
SOLE MAKERS OF
Wright & Newton's Patent Projecting Microscopes
FOB ELECTBIC AND LIME LIGHT. See page 243 of this Book.
SOLE MAKEBS rj Q I M f* I CT Q I CTT See page 55 of
OF nK I IM VJ Lt O J t I , this Book.
SOLE MAKERS OF
NEWTON'S PATENT 'REFULGENT' LAMPS.
See page 6 of this Sook.
Largely used by Professional Photographers and the Trade for Enlarging purposes.
Newton's Patent Microscopic Attachment,
To fit on any Lantern. See page 242 of this Book.
Full Illustrated Catalogue of Lanterns, Slides, &c., ad.
"KT-*. __^ fl MANUFACTUBIHG OPTICIANS TO THE QUEEN
l\l QWTnn Or I n AND H ' K H - THE ^ BINCE OF WALES.
I V II W I XI I 1 1 1 Makers of Lanterns & Slides to the Admiralty,
ll U If lUJI Ok. U U the War Department, the Science and Art De-
3 partment, and the principal Scientific Societies,
3, FLEET STREET, LONDON.
SPECIAL LIST OF MATERIALS
MAWSON & SWAN,
33, SOHO SQUABE, LONDON,
And 11-15, MOSLEY STREET, NEWCASTLE-ON-TYNE.
Works : Newcastle and Gateshead.
Optical Lantern * Slides
Occupy the most prominent position in the market.
NINE MEDALS AWARDED FOR EXCELLENCE.
Negatives Purchased. Slides made from Amateurs' Negatives.
87, LANCASTER ROAD, NOTTING HILL, LONDON. W.
SCIOPTICON. Optical Lantern.
Oil Lamp, giving more, whiter, and steadier light than any
other, fitted with simple and perfect Slide Changer ............ 4 10
SCIOPTICON. Lantern Slides.
Unapproaf hable f or tone, brilliance, and transparence, per doz. 10
List and Sample sent free to any part of the world for Is. 6d.
SCIOPTICON. Camera&Lenses for Lantern Slides.
Indispensable for artistic work. Range of camera and lenses,
3 to 12 inches ; 5 lenses, making 4 rectilinear ; 4 double
dark slides ; packed in handsome case ; rigid stand, the whole
i-plate outfit weighing under 7lb., price ........................... 10 10
GEORGE SMITH, 26, Colebrooke Eow, London, N.
(Trading as the S-IOPTICOtf COMPANY.)
WEATTEN & WAINWRIGHT'S
New Enlarging Lantern
great efficiency with extreme portability,
and gives the highest satisfaction for the quality
^-* of its results and the ease and facility with which
it may be manipulated. It is without doubt the best
enlarging lantern in the market.
SPECIFICATION. Copper body; first quality con-
denser; improved bellows front; cabinet portrait lens;
patent circular wick to lamp; carriers for small-sized
Prices, Particulars, &c., on Application.
COMPLETE ILLUSTRATED CATALOGUE, containing par-
ticulars and prices of every article required in the practice of
photography, with notes on development and other operations,
post free, SIXPENCE.
TRTratten & "Wain-Wright,
Sole Manufacturers of the "LONDON" DRY PLATES,
38, GT. QUEEN STREET, LONG ACRE,
The Melsenfrach Improved -Process of Engraving Paintings,
The Meisenbach Improved Processor Engraving Pencil Drawings
The Meisenbach Improved Process of Engraving Photographs,
The Meisenbach Improved Process of Engraving Wash Drawings
US THE BEST>
The MEISENBACH BLOCKS are now used for the
Illustration of all the leading Art Publications
and Illustrated Papers of the day.
Specimens and Full Particulars post-free on application to THE
MEISENBACH COMPANY, LIMITED,
JST USTOIR'WOOID- ***
Qarion j _ Jghoto -_ UPJy_ jgtarehouse.
For Lantern Transparencies.
GIVING THE FINEST TONES,- GOLD, MEDIUM, OR WARM.
These Plates have been in the market for some years, and give great satisfaction.
They are novr sent out m grooved boxes, thus preventing any risk of scratchiug or
markiug of the Plates by the Tissue Paper.
Messrs. BOBIHSON & THOMPSON, of Liverpool, write of these Plates on
October 2, 1888,
' ' The Cowan's Transparency Piates lately received in grooved boxes were
simply perfection. There was not a flaw on them of any kind."
PRICES IN GROOVED BOXES.
3 x 3i
8* x 6|... .
4i x 3i
9 x 7 ... .
10 x 8 ... .
6j x 4
12 x 10... .
71 x 5
13 x 8
* CHLORO - BROMIDE PLATES, *
SPECIALLY PREPARED FOR' MAKING LANTERN TRANSPARENCIES BY REDUCTION IN
THE CAMERA, OR BY CONTACT.
x fii , 10
x 7 . 12
METAL MINIATURE CAMERA,
MADE SPECIALLY POS LANTEEN SLIDES.
Fitted with a Voigtlender's Rapid Euryscope Lens, which, when not in use, racks
into ihe body of the Camera. The Lens ia of the best construction to secure sharp
definition, so necessary in Lantern Slides, which, when thrown on the screen, if the
Negative be not sharp, will enlarge all defects ; besides the quality of Lens, the
Metal Camera itself is so compact and bandy that with 12 Slides it may be packed
in about 8J by 6 in. Price complete with 12 Slides, Q. 10 S. 6d.
MARION'S NEW ENLARGING APPARATUS 4 MAGIC LANTERN.
Fitted with Compound Condensing Lenses. 8J inch, and Patent 3- wick Paraffin
Lamp, giving a very powerful light. Price 7.
MARION & LQ,,22&23, Soho-sq, London.
GEORGE HOUGHTON & SON,
89, High Holborn, London, W.C.
NEW SHOW-ROOMS FOR PHOTOGRAPHIC APPARATUS NOW OPEN.
Specialty for Dark Room Developing
Sinks, Lanterns, and Fittings.
ENLARGING & REDUCING
Prize Medal, Crystal Palace Exhibition, 1888.
THE " ECLIPSE" CAMERA,
Rigidity, and all latest
improvements, at the
lowest possible prices.
Complete Sets of
PRICE * LIST + FREE * ON * APPLICATION.
LANTERNS AND APPARATUS.
Member of the Lecturers' Association,
22, Gray's Inn Road
Dissolving > View > Artist
- AND MANUFACTURER -
TO THE TRADE, CLERGYMEN, LECTURERS,
EXHIBITORS, AND SCIENTIFIC INSTITUTIONS.
Second-Hand and New Apparatus and Slides in
Great Variety. Lists Free.
Slides produced from Amateurs' or Professionals'
own Negatives (glass or film), and supplied plain or
LANTERNS Complete, with 4-in. Condensers, from 36s.
SLIDES, 12s. & 15s. per doz. Coloured, 18s., 24s., & 30s.
Always a large collection of cheap sets from 12s. per doz., coloured.
LANTERNS MAY BE SEEN AT WORK DAT AND NIGHT.
22, Gray's Inn Road, London, W.C.
PHOTOGRAPHIC APPARATUS, LENSES, &c.
IN GREAT VAEIETY.
PUBLISHED EVERY FRIDAY. PRICE 2o.
AMATEUR * I A pop tu r nr rated
the kindred Aris.
Edited by CHARLES W. HASTINGS.
fye Jlmctfeur ^fyotogvcipfyey: is the
Special Organ of the Amateur Photographic
Societies of Great Britain and the Colonies.
Jlmateur ^gp^otocjrapBer contains
Articles upon all subjects, both Technical and
Social, interesting to Amateur Photographers.
B JltttClf<?ltT' ^Jp^ofocjtrcipBtMr has a special
page devoted to Queries and Answers.
^SBe Jlmafettr ^pBofograpl^er is the best medium for
the Sale and Exchange of new or second-hand apparatus.
London : Hazell, Watson, & Viney, Ld
52, LONG ACRE, W.C.
And through all Newsagents and Photographic Dealers.
^ SPECIMEN COPY FREE ON APPLICATION. ^
10s. lOd. per year, 5s. 6d. for 6 months.
G. W. WILSON & CO.
f^er fKajestg in
2, ST. SWUBffl STREET, ABERDEEN,
Publish the best and most complete series extant of
Photographic Views of ENGLAND and SCOTLAND.
mHEIR SB RIBS contains views of almost every note-
worthy district in Great Britain, from Land's End to
John o' Groats. It includes London, complete series of the
English Cathedrals, The Thames, Oxford and Cambridge,
Shakespeare's Country, Bristol and the West of England, the
"Dukeries," Derbyshire and the Scenery of the Peak, Yorkshire,
its Cathedrals and Watering Places ; and in Scotland, a complete
set of Edinburgh, Glasgow, Aberdeen and the large Towns, the
Scenery of the Borders, the Land of Burns, the Trossachs, the
Firth of Clyde, the Lochs, Bens, and Glens of the Highlands and
West Coast. Views illustrative of the Scottish Crofters, Deeside
and Balmoral, Orkney and Shetland, &c.
All or any of which can be had as Lantern
Ltctnre Season, 1888-M.
Mr. T. C. HEPWORTH,
IS NOW BOOKING DATES FOR HIS
Popular & Scientific
MR. HEPWORTH begs, to call attention to
the following Lectures, all of which
are lavishly illustrated by Limelight Pictures
mostly in the form of (Dissolving Views, their
size being only limited by the capacity of the
Footprints of Charles Dickens.
This new Lecture combines readings from a most popular author, with limelight
illustrations, and represents a totally new form of Entertainment, which is sure to
prove attractive. It is illustrated by about 100 Pictures. For details of this im-
portant Lecture see separate circular.
Old and New London.
A fully illustrated account of the City as it was before the time of railways,
contrasted with its appearance to-day. Many beautiful pictures of old buildings
now pulled down are included in this Lecture, which also comprises instantaneous
Photographs of modern London and its people.
Earthquakes and Volcanoes.
With Illustrations from nature, many of them having been taken by the Lecturer
at the scene of disturbance.
For Terms and Dates, address
MR. T. C. HEPWORTH, F.C.S,
45, ST. AUGUSTINE'S ROAD, CAMDEN SQUARE,
COMPLETE SETS OP
Photographic Apparatus for Tourists & Aiateurs.
New Ready Sensitised Paper, Photo Mounts of first-
class quality, and every requisite in stock.
All Orders mailed same day as receipt of Remittance.
DOUBLET'S MAGIC LANTERNS & SLIDES.
A LARGE AND CHOICE SELECTION
IFOIR S-A.LIE OE-
The "BIJOU " Set of Lanterns and Slides, from 10s. 6d.,
complete in Box.
T. & H. DOUBLET'S CELEBRATED SPECTACLES,
In Gold, Silyer, and Steel, fitted with the best Brazilian Pebbles or Periscopie
Lenses of the finest quality.
Price Lists and full particulars on application.
T. & H. DOUBLET, 11, Moorgate-st, Bank, E.G.
J. OTTWAY & SON,
Wholesale and Retail Manufacturers of
Improved Optical, Bi-Unial& Tri-Unial Lanterns,
WITH EVEKY MODERN IMPROVEMENT,
IMPROVED JETS AND GAS DISSOLVERS.
New Designs in Mechanical Slides and Effects, painted by first-
class Artists. Projecting Polariscopes and Microscopes.
Sole Address : 178, ST. JOHN STREET ROAD,
(Near the " Angel") LONDON, B.C.
THE DOCRAW TRIPLE,
Prize Medal, Highest Award, Photographic Exhibition.
fitted with High-class Objectives.
THE GRAND TRIPLE,
Will give from 10 to
30 feet pictures.
HUGHES' NEW LARGE-DIAMETER LONG-FOCUS OBJEC-
TIVES, for projecting a Picture at a very long distance without loss of light.
Most splendid definition and results, as supplied to B. J. Maiden, Esq., Rev.
Frank White, Colin Docwra, Esq., who pronounce them perfection. (See
Testimonials and Opinions of the Press).
HUGHES' PATENT OXYHYDROGEN MICROSCOPE, also
NEW MICROSCOPE ATTACKMENT; will show Eye of Fly 16 ft. in diameter.
HUGHES' EXPERIMENTAL LANTERN, with a Pamphengos
or Limelight for showing solid objects, as constructed for W. Lant Carpenter,
Esq., B.A., B.Sc., for the Victoria Hall, London, at from 80 to 100 feet from
screen ; also Free Trade Hall, Manchester, for Prof. Forbes, with tremendous
success, to over 5,000 working men.
ELABORATELY ILLUSTBATED CATALOGUE, PULL OF VALUABLE IMTOBMATION,
300 PA.QBS, Is., POSTAGB 4d. ; DITTO PAMPHLET, 4d., POSTAGE Id.
W. C. HUGHES, Brewster House, Mortimer Rd, Kingsland.
GIVES BRILLIANT 12 FEET PICTURE.
B. J. MALDEN, ESQ., COMPARES IT TO LIMELIGHT.
Price from 2. lOs.
PATENT TRIPLEXICON, 4 inch double Condensers, 2. 2s.,
3 inch, 1.15s. 6d., the finest 3-wick Lantern in the world.
See opinion of Sir Antony Brady, Dr. Croft, &c.
EDUCATIONAL DUPLEXICON, 31 inches, 1. 7s. 6d.
PATENT BIJOU" ENLARGING LANTERN.
PORTABILITY, PERFECTION, RAPIDITY.
The only perfect Enlarging Lantern. No Amateur Photographer should be
without one. Rectangular or Square Condensers exactly the shape of negative,
therefore reduces Lantern half the size. Prices from 8. 10s. List free.
First-class Bi-Unial, brass front, jets, dissolver, gas bags, &c., complete, only
Semi-Automatic Self Centreing Carrier, Presto-Instantaneoua Carrier, an
Articulosus Screen Frame Pandiscope Lantern Stretcher, marvelleous effect,
&c. 60,OJO Slides, 300 Lectures, 50 sets of Life Model Subjects, Pantomimes, Ac.,
from Is. each. Art Gallery, Workshops, &c. JS"ew elaborately Illustrated Cata-
logues, 300 pages, full of valuable information, 160 woodblocks, Is., postage 4d. ;
ditto, pamphlets 4d., postage Id. Cheapest ana best, of tbe manufacturer,
W. C. HUGHES, Patentee & Specialist,
Breuister House, Mortimer-rd., Kingsland-rd, , London, H.
For all those interested in the
PRACTICE OF PHOTOGEAPHY.
PUBLISHED ON THE 1st OF EVERY MONTH.
Yearly Subscription, including Home Postage ... ... 7 6
To the Continent, Canada, United States, and Egypt ... 76
To West Indies and South America 90
To the East Indies, China, Ac 10 6
To South Africa 12
To Australia, New Zealand, &c 14
ALL SUBSCRIPTIONS ARE PAYABLE IN ADVANCE,
Vols. I. and II., profusely Illustrated, are now ready,
and can be had of the Publishers, price 8s. 6d. each,
post free, 9s.
WYMAN & SONS,
74, 75, 76, GL QUEEN STREET, LONDON.
MORGAN & KIDD,
INVENTORS OF THE
The Standard Method of Producing Permanent Enlargements and
Price List of THE ARGENTIC-GELATI NO-BROMIDE PAPERS.
POSITIVE PAPER. For Enlarging and Printing direct from
(2-dz.) 1/3 10 x 8
1/9 15* x 124
2/3 18 x!5
In Rolls of 20 ft., 17 in. wide, 12s. ; 25 in. wide, 17s. 6d. ; and 39 in. wide, 21s. The
Positive Paper can also be had with a rough surface, same price, but in all cases,
unless rough is specially ordered, smooth is aent.
NOTE The Argentic-Gelatino-Bromide Papers are sent post
free. SAMPLE SHEET, 23xl7i Is. 6d.
NOTE. By this process beautiful enlargements may be
made with the ordinary optical lantern.
By MORGAN & KIDD,
From good small Negatives, are full of Delicacy and Vigour and
Equal to a Fine Engraving.
ARTISTIC, PERMANENT, AND INEXPENSIVE.
An Enlargement from a good negative is A PICTURE AND A WORK OF AKT, and
is far better than a photo- scrap.
SEND FOR FULL PRICE LIST POST FREE ON APPLICATION.
ARGENTIC - GELATINO - BROMIDE WORKS,
KEW FOOT BO*D, RICHMOND, LONDON, S W
PARIS 29, BOULEVARD DES ITALIKNS. Telegrams - Argentic, Richmond, Surrey.
MAYFIELD'S POCKET CAMERA
For Uiitera Slide Pictnres. sto 3! x 3S in.
Exceedingly portable, when closed for the pocket, measuring
4 X 4 X 1-| in., is the Lightest and Smallest Camera made for the size of picture.
C^- The Camera is made in polished Ebonite, and is quite unique in its appearance. -^
With this Camera held in the hand, Instantaneous Pictures can
be taken in bright weather, of which many examples have been
done, as Streets in the City, with the regular traffic ; views of Ship-
ping, &c., on the river ; open view from Kailway Carriage Window
when travelling at a rapid rate ; Country Scenes of Cattle Feeding,
&c. &c. It can, as well, be used with a stand for longer exposures.
The price of the Camera, with one Double Dark Slide, Lens, and
Shutter complete, is 3. IDs. Extra Dark Slides, 7s. 6d. each.
Portable Stand, which can be used as a Walking Stick, the three
legs fitting into one tube, 17s. 6d.
Special Plates, most rapid procurable, to use with Shutter Ex-
posure, Is. 6d. per dozen ; ordinary rapidity, Is. 3d. per dozen.
MAYFIELD, COBB, & CO., Lim.
41 & 35, QUEEN VICTORIA ST., LONDON
Makers of Dry Plates, Cameras and Photographic Requisites
Mayfield's Universal Developer, in one Bottle, does not stain the
fingers, and can be used with any mafce of plates. A boon to any
Amatenr. In bottles, 2s. Particulars on application.
W. WATSON & SONS;
313, HIGH HOLBORN,
MANUFACTUBBBS OF AND DEALERS IN
HIGHEST CLASS OPTICAL LANTERNS AND APPARATUS.
Scientific Accessories for use with Lanterns.
MECHANICAL AND DISSOLVING VIEW EFFECTS.
Photographic Lantern Views from all parts of the World.
from .7. 10s.
from 15. 15s.
Of highest quality, for
burning Paraffin Oil, from
1 4 GOLD & other
Medals at various
Excellence of In-
>t J/luxfrafed Catalogue
qfLuntertts and lit of
Accessories and Slit1e
tent pr>st free to ai<y
part of the world on
W. WATSON &
313, HIGH HOLBORH, LONDON.
Steam Factory 9, 10, 11, Fulwood's Bents, Holborn.
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UNIVERSITY OF CALIFORNIA LIBRARY