Part 5

Blumenthal (Flower valley),

etc., etc.

Our Christian names are from similar sources, and while many of them are well selected because of their beautiful meanings, there are many of them which mean nothing as words as they were only invented for the purpose of giving a new name to a new child.

Why Can You Blow Out a Candle?

When you light a candle it burns, because the lighted wick heats the wax sufficiently to turn it into gases, which mix with the oxygen in the air and produce fire in the form of light. You know it is not easy to light a candle quickly. You must hold the lighted match to the wick until the wax begins to melt and change to gases. As long as the wax continues hot enough to melt and turn to gas the candle will burn until all burned up; but if there is a break in the continuous process of changing the wax to gas, the light will go out. Now, when you blow at the lighted candle, you blow the gases which feed the flame away from the lighted wick, and this makes a break in the continuous flow of gas from the wax to taper, and the light goes out.

The Story in a Photograph

How Does a Camera Take a Picture?

When we look upon the surface of a mirror we see the image of ourself and our surroundings. The extent of the view depends upon the size of the mirror and the distance we are standing from it.

If we hold the mirror close to our face we see only the face, or perhaps but a portion of it, and the farther away we are the more the mirror will reflect, only, of course, the various images will be smaller. The mirror reflecting exactly what the eye sees, without doubt had a great influence in inducing the experiments that resulted in the process we call photography.

The taking of a photograph with a camera may in a way be compared with the action of your eyes, when you gaze upon your reflection in a mirror, or look at any object or view. Any object in a light strong enough to render it visible will reflect rays of light from every point.

Now, the eye contains a lens very similar in form to that used in a camera. This lens collects the rays of light reflected from the object looked at and brings them to a focus in the back of the eye, forming an image or picture of whatever we see, just as the mirror collects the rays of light and reflects them back through the lens of the eye.

Certain nerves transmit the impression of the image so focused in the back of the eye to the brain and we experience the sensation of sight.

What Is the Eye of the Camera?

The lens is the eye of the camera, and the process we call photography is the method employed to make permanent the image the eye or lens of the camera presents to a sensitive surface within the camera.

Fig. 1 shows a simple form of camera, it being merely a light tight box with a lens fitted to the front, and a means for holding a sensitive plate at the back, the plate being placed at just the right distance to focus the rays of light admitted through the lens in exactly the same manner as the rays of light pass through the lens of the eye and come to a focus in the back part of the eye.

Now, if we could look inside the camera we would note that the image was inverted, or upside down.

Fig. 2 will explain this.

The rays of light from “A” pass in a straight line through the lens “B” until they are interrupted by “C,” upon which they strike, forming an upside down image of the object “A.” But, you exclaim, “we do not see things upside down.” No, we do not, because some mental process readjusts this during the passing of the impression from the eye to our brain.

Let us suppose we have our camera loaded with its sensitive plate or film. We select some object or view we wish to photograph, uncover the lens for an instant, and let the light impress the image upon the sensitive surface of the plate or film. Now, how are we going to make this image permanent?

If we were to examine the creamy yellow strip of film upon which the picture was taken there would seemingly be no difference between its present appearance and before the snapshot was made.

Now let us suppose that this strip of film is a little trundle bed, and in it tucked securely away from the light are many hundreds of little chaps called silver bromides, little roly-poly fellows lying just as close together as possible, and protected by a coverlet of pure white gelatine.

~HOW A PHOTOGRAPH IS DEVELOPED~

Until the sudden flash of light in their faces when the picture was taken, they have been content to lie still and sleep soundly. Now they are seized with a strange unrest, and each little atom is eager to do his part in showing your picture to the world. Alone they are powerless, but they have, all unbeknown to them, some powerful chemical friends, who, organized and aided by the photographer, will bring about their transformation. These chemicals, with the help of the photographer, form themselves into a society called the developer.

The photographer takes just so many of the tiny feathery crystals of pyro, just so many of the clear little atoms of sulphite of soda, and just so many little crystals of carbonate of soda, and tumbles them all into a beaker of clear cold water. Unaided by each other, any one of these chemicals would be powerless to help their little bromide of silver friends. The first of these chemicals to go to work is the carbonate of soda.

He tiptoes softly over to the trundle bed and gently begins turning back the gelatine covers over the little bromide of silver chaps, so that Pyro can find them in the dark.

It is Pyro’s mission to transform the little silver bromides into silver metal, but he is rather an impulsive chap, so he is accompanied by sulphite of soda, who warns him not to be too rough, and whose sole mission is to strain his eagerness to help his friends.

“Go slow now,” says Sulphite, “don’t frighten the little silver bromides, or else you’ll make them cuddle up in heaps, and the picture won’t be as nice as if you wake them up gently and each little bromide stayed just where he belonged.”

After all the little silver bromides that the light shone on have been transformed into metallic silver by the developer, another chemical friend has to step in and carry away all the little bromides that were not awakened by the flash of light.