Very often this system is used in connection with the ventilation. The radiators are placed in the basement or in another convenient place and cool fresh air from the outside is passed over them and warmed. It is then forced into the rooms. Very often this air is washed, as described in the chapter on ventilation, and thus freed from suspended matter. At the same time the relative humidity can be controlled and this is very essential, not only as a means of providing air that is most desirable for breathing, but also in point of fuel economy, since air of high humidity is more easily heated and is more desirable in conserving the heat of the body as has already been explained. Steam heating is especially suitable for high and irregularly shaped buildings. The fact that the radiators and pipes are empty when not in use reduces the risk of damage to the house furnishings from bursted or leaky pipes.
It is well to have the radiators placed near windows so that in ventilating the air will pass over them and be warmed before entering the room.
CHAPTER VI
LIGHTING
LIGHTING
Adaptability of Eye to Light
DIFFERENCE IN INTENSITY OF LIGHT
TIME REQUIRED FOR ADAPTATION
The Eye
MECHANISM OF EYE
ACTION OF LIGHT UPON THE EYE
INTELLECTUAL ADAPTATION NECESSARY
Value of Sunlight
EFFECT UPON HEALTH
ACTION IN NATURE
Natural Light in Buildings
DIRECT RAYS OF THE SUN
FACTORS DETERMINING THE AMOUNT OF LIGHT ADMITTED
REFLECTED LIGHT
LOSS OF LIGHT THROUGH DIFFERENT GLASS
WINDOW AREA REQUIRED
Artificial Lighting
EFFECT UPON THE EYES
EVOLUTION OF LIGHTING SYSTEMS
BEST MEANS OF LIGHTING
OBJECTIONS TO OPEN BLAZE FOR LIGHT
DIRECTION OF LIGHT
Psychological Effect of Light
INFLUENCE UPON THE EMOTIONS
SOFT LIGHT SOOTHING
BRIGHT LIGHT STIMULATING
Systems of Lighting
DIRECT
INDIRECT
SEMI-INDIRECT
EFFECT OF INSUFFICIENT LIGHT
CHAPTER VI
LIGHTING
Adaptability of Eye to Light
The eye has a great range of adaptability to the intensity of light. This is evidenced by the fact that the eye is readily adapted to the intensity of the bright sunlight or to the soft rays of the moon. In both instances there is no disturbance in vision, even though the intensity of illumination at midday when the light is brightest is almost a million times greater than the illumination from the full moon on a clear night. This adaptation takes place so perfectly and so independent of the educated mind that we give little thought to the great difference in intensity of light.
It must be remembered, however, that although this adaptation takes place so perfectly and without any apparent difficulty, it requires an expenditure of Innate force to accomplish this action. If the change takes place too rapidly from a soft light to an intense light, without sufficient time for adaptative action to take place, the delicate structure of the eye will be damaged by the violent light vibrations. The change from the soft rays of the moonlight to the intense illumination from the bright sun takes place gradually. First, the night; next, the gray dawn of morning; and then comes the sun, whose rays are softened as they pass through a maximum amount of atmosphere near the horizon, and as the sun approaches the dome of the arc, the rays become more intense, since they pass through less of the earth’s atmosphere. Then the process is reversed as the intense light from the sun gives way to the softer rays from the moon.