Sources of light
Light rays travel from the source-the sun, moon and the stars-through space without the necessity for any material medium. Heat and light rays are only small parts of the great range of waves in the outer space, all of which are electromagnetic in character. All these rays which include the X-rays, ultraviolet and wireless waves travel with the same speed but differ in the frequency of vibrations and the disturbance they propagate. The source of all natural light is solar radiation but light can also be produced artificially by heating a body to incandescence ie sufficiently to make it glow. The more intense the heat the brighter the light emitted. Light rays are detected by the retina of the eye which can be described as the spread-out end of the optic nerve. It can also be detected artificially by a photographic plate.
Light rays in themselves are invisible those in the visible spectrum being made visible by reflection off material objects. Light travels in straight lines at about 186000 miles per second. The medium through which it travels may be quite clear and pass light freely, when it is described as transparent. Alternatively it may be transluscent capable of passing some light but not sufficient to render the outline of the objects distinctly visible. Most substances are opaque or incapable of passing light rays.
Day light is produced by the sun and consist the seven visible colours of the spectrum. If all these colours are viewed through space with none absorbed the appearance is white. If on the other hand all the colours are absorbed by an object we say the object is black. Different materials absorb different colours of the spectrum, those not reflected back to the retina and so the material appears to be green, red etc. when while daylight is split into the seven colours of the sun shining on or through a rain cloud, a rainbow is seen in which all the seven colours can be distinguished-red, orange, yellow, green, blue, indigo and violet.
Natural Lighting
In this country the ultraviolet light rays in natural daylight are never strong enough to harm the eyes. In modern private houses all rooms should be well supplied with window space which should amount to not less than one third of the total space. The windows should be kept clean and cotton such that can be completely drawn back to expose the whole windows during daylight. Daylight reveals dust and dirt in corners and crevices and discourages the growth of microorganisms. Windows should not be blocked with heavy furniture but left clear and accessible. In modern buildings, architects make use of the knowledge that shining surfaces and light shiny paint greatly increases the effect of natural lighting, so light coloured paints are used.
Artificial Lighting
Artificial lighting of some sorts is necessary in all inhabited places. It has the advantage of being relatively safe, clean, quite and labour saving and capable of being regulated and is generally most effective. Like most other highly convenient services it is expensive. Sources of artificial light include the candle, oil lamps, gas lighting and now electricity.
Healing words
Wherefore lift up the hands which hang down and the feeble knee. And make straight paths for your feet lest that which is lame be turned out of the way. Hebrews 12: 12-13.
It is God’s will for you to be healed no matter what the infirmity is. Jesus went about healing all manner of diseases. His power to heal is ever present with us. If you can have faith in Christ He will surely save your soul and heal your infirmities.
