Color.
In what way is the sun useful to us?
It gives heat, which makes us warm, and it gives light, so that we can see.
Is it useful in any other way?
It gives light and warmth to all animals as well as to all plants.
What make the flowers and leaves so beautiful?
The light and heat from the sun make them beautiful.
What do the light and heat from the sun ripen?
They ripen the apples, cherries, and other fruits; also, the wheat, corn, and other grains, and make them fit for food.
When it is night-time or dark, can we distinguish objects?
No; because all things are then without color, and they cannot be seen.
As it grows light in the morning, what takes place?
At first, we see the objects around us faintly; but as it grows lighter, we see them more distinctly.
Do they all show the same color in the light?
They do not; they show different colors.
What enables us to see the color of different things?
Light enables us to see the color of everything.
What kinds of light have we?
We have the light of the sun, moon, and stars; also, the light from the burning of any substance.
Does the light show many colors?
It does show many colors or shades of color.
How may some colors be made?
They may be made by mixing other colors together.
How can we make a purple color?
By mixing a red and a blue color together.
How can a green color be made?
By mixing a blue and a yellow color together.
How can an orange color be made?
By mixing a red and a yellow color together.
How does the light come from the sun?
It comes in rays or straight lines.
What may be done with a ray of light?
It may be separated into different colors.
Into how many colors may a ray of light be separated?
Into seven colors, like the colors of the rainbow.
What names are given to these colors?
Red, orange, yellow, green, blue, indigo, violet.
How may these colors be separated?
By a prism, or three-sided piece of glass.
How may this be done?
If a sunbeam, shining through a hole in the window-shutter of a dark room, should fall upon a prism, it will be broken up as it passes through the prism, and be shown on the opposite wall, in the seven rainbow colors.
Fig. 6.
In [Fig. 6], D is a sunbeam passing through a shutter. When it passes through the prism, at E, it is separated into the seven rainbow colors, as is shown on the opposite wall.
In what order will these colors appear?
They will always appear one above the other, in the order named.
How may this order be remembered?
By the word Roy-g-biv, made from their initial letters, beginning at the bottom.
From what are the colors of the rainbow made?
From the rays of light coming from the sun.
When is a rainbow seen?
A rainbow is seen when the sun shines through the drops of water as they fall through the air.
How do the drops of water help to make a rainbow?
The drops of water act like little prisms, and separate the rays of light passing through them into the colors of the rainbow.
What two things, then, are needed to make a rainbow?
A shower of water, and a bright sunshine.
In what part of the sky does the rainbow appear?
In the part opposite to that in which the sun is, at the time of the shower.
How does the rainbow appear?
It appears like a great arch, spanning the sky, and its splendid bright colors are very beautiful.
What may we remember in reference to the rainbow?
We may remember that God set his “bow” in the cloud, as a token that the world should no more be destroyed by a flood of waters.
Where else may we see a variety of colors?
In the soap-bubble.
Why are these colors constantly changing?
Because the walls of the bubble are constantly growing thinner, and different colors are, therefore, reflected from them.
Why do the walls of the soap-bubble grow thinner?
Because the water runs to the bottom of the bubble until its top becomes so thin as to burst.
Can we tell the color of any object by touching it?
No; we must see it in order to tell its color.
How do we know this?
If there are two coats, one blue and the other black, we cannot tell which is the blue one or which is the black one, by feeling them.
What is necessary in order to see the colors?
Light is necessary; because all colors come from the rays of light.
Can we see the different colors in the ray itself?
We cannot; because God has so blended them together that they cannot be seen by us.
When most of the rays of light pass through a substance, what is said of it?
The substance is said to be transparent.
Name some transparent substances.
Glass, ice, diamonds, air, and clear water.
When only a few rays of light pass through a substance, what is said of it?
The substance is said to be translucent.
Name some translucent substances.
Flint, isinglass, scraped-horn, and china-ware.
When no rays of light pass through a substance, what is said of it?
The substance is said to be opaque.
Name some opaque substances.
Wood, iron, coal, and granite.
Can we see through a glass window?
Yes; because the glass is transparent, and the light passes through it.
Can we see through a looking-glass?
No; because the back of the looking-glass is covered with quicksilver, which prevents the rays of light from passing through it.
What becomes of the light falling on the looking-glass?
It is thrown back from the glass.
What is this called?
It is called reflection.
What objects are good reflectors of light?
Those having smooth and polished surfaces; such as tin, silver, gold, and quicksilver.
What objects are poor reflectors of light?
Those having dull, uneven surfaces; such as iron, wood, cloth, leather, and calico.
Of what is every ray of sunlight composed?
It is composed of the seven colors of the rainbow.
What does a looking-glass do with these colors?
A looking-glass throws them all back from its surface.
What does a glass window do with these colors?
A glass window permits all these colors to pass through it.
What do opaque substances do with these colors?
They throw back or reflect some of them.
Do they all reflect the same color?
No; some reflect one color, and some another color.
What color does the grass reflect?
It reflects the green color; therefore, the grass is green.
What does the grass do with the other colors?
It absorbs or hides them in itself.
How do we know the color of anything?
We know it by the color which it reflects.
Why is the rose red?
Because it reflects the red color, and absorbs or hides the other colors in itself.
When anything absorbs all the colors of a ray of light, what color is it?
It is black.
When it reflects all the colors of light, what color is it?
It is white.
Why are the letters on this page black?
Because they absorb all the colors of light, and reflect none.
Why is the paper white?
Because it reflects all the colors of light, and absorbs none.
Why are all things black in the dark?
Because there are no rays of light falling on them; hence, there is no color for them to reflect.
Does an object reflect its color in every direction?
It does reflect its color in every direction.
How do we know this?
Because thousands of persons, in different directions from the same object, can see it at the same time.
How are the rays of color reflected from an object?
They are reflected in straight lines.
Where must a person be so as to see an object?
He must be in a position so that there is nothing to prevent the rays of light passing in a straight line from the object to his eyes.
What color does a red ribbon reflect?
It reflects a red color.
Why are some red ribbons of a brighter red than others?
When they reflect a great many red rays, they are of a bright red color; but when they reflect only a few red rays, they are of a dull red color.
Upon what does the brightness or dullness of a color depend?
It depends upon the number of rays of that color reflected.
What variety does this produce?
It produces a great variety in the shades and tints of color.
Where may many of these shades and tints be seen?
In the pretty flowers that grow in the woods, fields, and gardens; in the beautiful tints of the leaves in autumn; and in the plumage of the birds that visit us every spring, and cheer us with their songs.
What may these things teach us?
They may teach us the goodness of God, in giving us a world so full of beauty; and we should feel ever thankful to Him for the great pleasure that we have in seeing them.
Why cannot we see the light of a lamp or candle distinctly, in the day-time?
Because the strong rays from the sun hide the more feeble rays from the lamp.
Why cannot we see the stars in the day-time?
Because the bright light from the sun hides their more feeble light.
When can we see the glow-worms or fire-flies best?
At night, when it is dark; because, at other times, the light of the sun hides their feeble light.
Where may we see them at night?
Flying about in all directions, looking like bits of fire moving in the air.
Does a looking-glass reflect all the colors of light falling upon it?
It does; hence, the ray of light is not changed.
When the object is of a blue color, why is blue only reflected?
Because it is the only color falling upon the glass, and there is no other color to reflect.
Is the color of any object changed by falling upon a looking-glass?
No; the color of every object is reflected from a looking-glass without change.
Do other objects generally reflect the colors falling upon them?
They do not; they absorb or hide the color of all other objects, and reflect only their own color.
If every object was a good reflector of color, like a looking-glass, what would result?
Then every object would reflect the color of every other object around it, and there would be an endless confusion of colors.
What objects reflect the most light?
Those of a white or light color.
What objects reflect the least light?
Those of a darker color; and the nearer the color approaches to black, the less light it reflects.
Why is it darker when the sky is covered by dark-colored, than by light-colored, clouds?
Because the dark-colored clouds reflect less light, than the light-colored clouds do.
What advantage do we derive from the green color of the grass and the leaves?
They reflect a soft, pleasant light, which does not dazzle or hurt our eyes.
How would it be if those objects were white?
They would dazzle us by the amount of light reflected.
If we wish to make a room light, of what color should the walls be?
They should be white; and when papered, it should be with light-colored paper.
Why does dark-colored paper darken a room?
Because it absorbs some of the rays of light which come in at the windows; hence, there is less light in the room. Dark-colored carpets, or dark furniture, darken the room for the same reason.
Does the light from a burning body differ from sun-light?
Yes; it differs in intensity, in color, and in many other ways.
What effect does the lamp-light have upon the color of some substances?
It changes their color.
Where may we find an example of this?
In trying to match the colors of thread or silk at night.
Why is the color different by lamp-light from what it is by daylight?
Because the yellow color of the lamp’s rays acts upon the color of the silk, forming a third color. Blue silk becomes green by lamp-light, and red silk becomes orange.
Are all persons able to distinguish one color from another?
No; some are color-blind. To such persons all colors appear to be alike.
What curious instances of color-blindness may be mentioned?
Dr. Mitchell tells of an officer who bought a blue coat and a red waistcoat, thinking them to be of the same color. He also tells of a tailor who patched a black waistcoat with a piece of crimson; and of another, who put a red collar on a blue coat. Dr. Dalton lost a piece of red sealing-wax in the grass, and he could not find it because it and the grass seemed of the same color to him.