The recitation in Natural Philosophy was just over, and as the class was
leaving the room, Fred Ward whispered to his most particular chum, Jim
Davis: "I say, Jim, I've hit on an immense idea. Suppose that we set up
a photographic gallery. It will be splendid fun."
"That's so," answered Jim. "Let's talk it over."
By this time the French class room was reached, and conversation was for
the time suspended; but two o'clock found the boys leaving the
school-grounds, engaged in a grand confab about their new plan.
"Now those old fellows that invented all this," said Fred, "had to work
hard, because they had nothing to begin with; but as all that we want to
know is down in the books, I don't see why we can't take as good a
picture as the next one, as soon as we can get a camera and some
chemicals. Why, Jim, you can buy the whole rig for five dollars--yes,
you can--camera and all, with a stand to set it on."
"Oh, nonsense!" answered Jim; "I wouldn't give a cent to work in that
way. Why can't we make the box and mix the baths ourselves? Anybody
could buy the machine and take a picture, but it isn't every fellow can
make his own apparatus. Now in my Philosophy there are some pictures
that show how to put the box together, and we can save money to buy the
lenses, and it will be twice as much fun to do everything ourselves."
Jim was very handy with tools, and in a few days he constructed as neat
a camera as could be desired for a beginner. It consisted of two boxes,
one of which fitted into the other. The interior of the boxes was
painted black, so that the light through the lenses would be all the
plate could receive. In the front of the larger box, and directly in the
centre, a round hole was cut to receive the tube containing the lenses,
and at the back of the small box were grooves to receive the plate
slide. The making of that slide was the first serious stumbling-block in
the path of these young photographers.
[Illustration: SLIDE CASE.]
They searched through their books, and at last found a good diagram
which gave Jim the hints he needed for his work. He first built a frame
which fitted to the slide in the back of his camera box. This frame was
provided with a hinged door at the back, and a sliding door in front. In
order to receive plates of different sizes, Jim also made several plate
frames with larger or smaller openings. The plate frame fitted tightly
inside the slide frame, and was held firm by a spring fastened in the
centre of the hinged door, which pressed against the plate when the door
was shut. Another frame, exactly the same size as the plate frame, had
to be made to hold the ground glass upon which to obtain the focus for
the pictures. When the focus was regulated, the ground glass was to be
carefully withdrawn, and the sensitive plate placed in exactly the same
position.
Perseverance and school-boy grit having conquered the slide difficulty,
the perplexing question of the lenses came up. Fred's father, who was
watching the boys' undertaking with considerable interest, now came to
the rescue, and presented the young photographers with a fine set of
mounted Dallemeyer lenses with diaphragms, which he bought of a dealer
in photographic apparatus.
[Illustration: THE CAMERA.]
The camera being in readiness, Fred and Jim now went to work to mix
their baths. They began with the sensitive bath, but to their
astonishment, when they placed nitrate of silver in ordinary water, a
white cloud instantly formed. The text-book was at once consulted, and
Fred discovered that distilled water must be used. As the boys had no
long-necked retort with which to distill the water, they agreed to
suspend all operations until they could see their teacher on the
following day, and ask his advice.
The next afternoon, when school was over, the boys marched up to the
door of Professor Drood's class-room, and timidly knocked. "Come in,"
said a hearty, kindly voice. Fred, who was the most courageous, went in
first, and clearly stated the case, while Jim stood hesitating in the
doorway. "If you take rain-water, and filter it to remove the dust,"
said the Professor, "it will answer your purpose as well as distilled
water."
The boys thanked him, and were going away, when he called them back. "I
like to see you taking interest in things of this kind," said he, "and
if you will stop, I will give you the whole story as clearly as I can."
Fred and Jim were delighted to listen, and when the Professor told them
to take a pencil and note-book, and write down the proportions in which
the different baths were to be mixed, they were eagerly attentive at
once.
"The sensitive bath," said the Professor, "is prepared in this manner:
dissolve in two ounces of rain-water one ounce of nitrate of silver in
crystals. Then add two to five grains of iodide of potassium. You must
now add eight ounces of rain-water, and let the mixture stand two hours
to saturate. It must be kept in a dark chamber, where no rays of
sunlight can penetrate. You must always work by the light of a candle,
and it is a good plan to have a screen of yellow paper around the flame,
so that no direct light may fall on your sensitized plate.
"Before beginning to work, be sure that your plate is clean. Tin plates,
with which you would better work until you become skillful in handling
the baths, are sold in sheets by any dealer in photographic goods, and
when you buy them are often covered with fine dust. Polish them well
with a pad of soft chamois-skin before you proceed farther. Next pour
the collodion on the centre, and cause it to flow evenly by gently
tipping the plate from side to side. Allow the surplus to drip off into
a flask; and as collodion is an expensive article, you would better mix
some gum-arabic and water to about the required thickness, and practice
with that first, that you may not waste the more costly fluid by
failures to spread it evenly on the plate--a very difficult matter for
beginners to accomplish. This collodion is made of alcohol, ether, and
gun-cotton, and sensitized with certain iodides and bromides. It
evaporates if exposed to the air, and must be well corked, and kept in a
cool, dark place, as both lights and heat are injurious to it. A
positive collodion is often sold for ferrotypes, but the negative fluid
gives better results.
"When the film of collodion has become set, the plate is ready for the
sensitive bath. Place it on a strip of glass bent at the lower end,
which you will buy with your bath dish, and lower it into the bath
quickly; otherwise a line may be noticed on the finished picture, due to
the uneven deposit of silver. The deposit may be hastened by gently
moving the plate in the liquid. After a few seconds lift it out and
examine it. If it is streaked and greasy, it must be put back; but when
it is of a fine opaline tint, free from streaks and flaws, it is ready
to be placed in the camera, which should be already properly focussed
and in position.
"Now, boys, comes the great trouble--to correctly time the exposure. It
varies from five to forty-five or sixty seconds, according to the light,
the arrangement of your screens, and the condition of the silver bath.
[Illustration: THE FIRST ATTEMPT--SOMETHING WRONG.]
"When you think, from the nature of the case, that your plate has been
exposed long enough, close your slide, and return to the dark room,
where you now proceed to develop your picture. You must have already
mixed this developing solution: one fluid part of sulphate of iron, one
and a half fluid parts of acetic acid, and sixteen parts of rain-water.
Do not make too much of this at once, as it quickly becomes spoiled.
When you take the plate from the slide, you will see no alteration in
it, but when you pour on some of your developer, 'as if by magic a
picture appears.' See that the developer flows all over the plate, and
do not allow it to settle on any one place, as this would make a stain
which can not be removed.
"As soon as the development is complete, wash the plate well with pure
water, using for the purpose a wash bottle, which is simply a large
glass flask having a cork perforated by two tubes, one of which reaches
into the body of the liquid, while the other only passes through the
cork. The short tube is bent over at an angle so that the mouth may be
conveniently placed against it, while the long tube is bent, and drawn
out to a fine jet. On blowing through the short tube, the air in the
bottle becomes compressed, and in expanding drives the liquid through
the jet in a fine steady stream. When the plate has been well washed, it
must be treated with another solution, as this picture is one that would
soon fade, just as you no doubt have seen proofs of photographs do. To
remove the unaltered silver a solution of hyposulphite of soda in water
is used. Cyanide of potassium is also used, because it is much cleaner.
"But there is no rose without its thorns, and the cyanide makes up for
its cleanliness by being one of the most deadly poisons, and I would
advise boys who are not posted on the fine points of chemical
manipulation to have nothing to do with it. This fixing solution is made
of eight ounces of the hyposulphite and forty of water. Now if this is
made too strong, it will spoil the picture, so it is well to be careful
to have the exact proportions.
"By-the-way," added the Professor, "if you do use cyanide of potassium,
be very careful not to get any of it into what cuts or bruises you may
have on your hands. Boys always have such ornaments, and if the cyanide
touches a place where the skin is broken, it is liable to mix with the
blood, and make trouble.
"After your picture is fixed, wash it well and varnish it. Ten parts of
gum-arabic to one hundred parts of water will make a very fair varnish;
but as this has to be dried over a spirit-lamp, it is better to buy the
self-drying varnish which is sold for this purpose.
"All this sounds very easy and pleasant, but there are more
disappointments in store for you than can be imagined, for in this, as
in many other things, practice is as essential as rules and regulations.
I can only say to you, what should be the motto of every scientific
student, 'Make haste slowly.'"
The boys thanked the good-natured Professor, who told them, in any
serious difficulty, to come to him again. Then with eager steps they
hastened homeward.
[TO BE CONTINUED.]
[Illustration: MIDWINTER.]
WILD BIRDS IN THE COUNTRY.
When Aunt Bertha was younger than she is now she was a little English
girl, and her American nephews and nieces are never tired of hearing
about her English pets. Of her bird pets she tells the young listeners
as follows:
"When I was alone at home with my parents, I used to amuse myself during
my play-time, which I always spent out-of-doors, by trying to tame the
wild birds. I nailed a little wooden tray against an oak that had twigs
growing out of its trunk for the birds to perch on. It stood just inside
a wood on one side of the drive, but not too much exposed to the view of
the passers-by. Every morning regularly I filled the tray with
bread-crumbs and bird-seed, with a little piece of raw meat now and then
for a great treat. I watched anxiously to see what birds would come
first, and in a few days had the pleasure of finding three tomtits
hopping about my tree, and carrying off the crumbs and seeds. It was
delightful to have these pretty, sprightly little fellows, with their
bright yellow and black breasts and white cheeks, for my visitors,
instead of the rather vulgar-looking sparrows, that are generally only
too eager to secure any food that may be awaiting hungry mouths. The
next birds that came were a pair of chaffinches: the cock never became
very tame, but his little mate was soon a great pet with every one.
After a time I had twelve birds that fed regularly at my box; they were
a pair of tomtits, the chaffinches, a pair of nut-hatches, a pair of
coal-tits, a pair of marsh-titmice, a robin, and a hedge-sparrow. In
the cold weather my birds used to meet me as I came out of the house,
and fly after me to the wood. They were not at all afraid of Carlo, my
large dog, who generally accompanied me, and sat by the tree quite
quietly, expecting his little share of the feast. In the spring the
chaffinches built their nest in an oak-tree within sight of the box, and
when their young ones were hatched, they carried off nice large crumbs
to them.
"A robin that fed at the box used also to keep us company when we were
out, and hop about on our feet as we sat on the lawn. The dear little
thing came in-doors whenever he found a window open. He was particularly
fond of flying into my mother's bedroom, in which he thought he had
discovered a rival favorite. Day after day he attacked it most fiercely,
but as the rival was his own reflection in the mirror, the poor bird
only got a great many hard knocks against the glass in his efforts to
revenge himself on his fancied enemy. The mirror was sometimes smeared
with his blood."
[Begun in YOUNG PEOPLE No. 58, December 7.]
MILDRED'S BARGAIN.
A Story for Girls.
BY MRS. JOHN LILLIE.