Generally the term transparent is understood to mean that something is see-through, that is that light can pass through it so that objects beyond are clearly visible - like for example a standard window. The term is also applied to objects which allow the passage of radiant heat, other specific types of radiation or sound waves to pass through them. The opposite of transparent is opaque. Research Transparent
Sir William Crookes was an English physicist. He was born in 1832 and died in 1919. He studied chemistry at the Royal College of Chemistry, London, was for a short time connected with the Radcliffe Observatory, Oxford, was professor of chemistry at Chester Training College, founded the Chemical News in 1859, and since then resided in London as its editor and proprietor. He was elected a fellow of the Royal Society in 1863, was DSc of Oxford and Dublin, was knighted in 1897, and next year was president of the British Association. He made important researches and inventions in connection with molecular physics, radiant matter, and high vacua, and was a great authority on sanitation, while he was also a believer in spiritualism. He discovered the element thallium in 1861, invented the crookes tube in 1874 and also made valuable discoveries about radium. Among his works are: Select Methods in Chemical Analysis, Handbook of Dyeing and Calico-printing, Dyeing and Tissue-printing, Researches in Modern Spiritualism, Psychic Force and Modern Spiritualism, etc. Research William Crookes
In Greek and Roman mythology, Apollo was the god of the sun, music, poetry, prophecy, agriculture, and pastoral life, and leader of the Muses. He was the twin child of Zeus and Leto.
Apollo, being persecuted by the jealousy of Hera, after tedious wanderings and nine days' labour, was delivered of him and his twin sister, Artemis, on the island of Delos. Skilled in the use of the bow, he slew the serpentPython on the fifth day after his birth; afterwards, with his sister Artemis, he killed the children of Niobe. He aided Zeus in the war with the Titans and the giants. He destroyed the Cyclopes, because they forged the thunderbolts with which Zeus killed his son and favourite Asklepios.
According to some traditions he invented the lyre, though this is generally ascribed to Hermes. Apollo was originally the sun-god; and though in Homer he appears distinct from Helios (the sun), yet his real nature is hinted at even here by the epithet Phoebus, that is, the radiant or beaming. In later times the view was almost universal that Apollo and Helios were identical. from being the god of light and purity in a physical sense he gradually became the god of moral and spiritual light and purity, the source of all intellectual, social, and political progress. He thus came to be regarded as the god of song and prophecy, the god that wards off and heals bodily suffering and disease, the institutor and guardian of civil and political order, and the founder of cities. His worship was introduced at Rome at an early period, probably in the time of the Tarquins. Ancient statues show Apollo as the embodiment of the Greek ideal of male beauty. Apollo epitomized the transition between adolescence and manhood in Greek male society. Research Apollo
In Maya mythology, Ix Chel is the mother of deities, she is a wise, gentle, lustrous and radiant goddess of the moon and water. The Eagle Woman. Research Ix Chel
A bolometer is an electrical instrument, invented by Langley, which is sensitive to radiant heat, and who used it to make discoveries in the ultra red rays of the spectrum. Research Bolometer
In physics, calorescence is the conversion of obscure radiant heat into light; the transmutation of rays of heat into others of higher refrangibility. A peculiar transmutation of the invisible calorific rays, observable beyond the red rays of the spectrum of solar and electric light, into visible luminous rays, by passing them through a solution of iodine in bisulphide of carbon, which intercepts the luminous rays and transmits the calorific. The latter, when brought to a focus, produce a heat strong enough to ignite combustible substances, and to heat up metals to incandescence; the less refrangible calorific rays being converted into rays of higher refrangibility, whereby they become luminous. Research Calorescence
Diathermancy is the property that is possessed in various degrees by different substances of transmitting radiant heat. Bodies that are equally transparent, that is, bodies which have equal power of transmitting rays of light, are very different in their power of transmitting heat rays. Thus a thin plate of glass and a thin plate of rock-salt may be nearly equally transparent, but the plate of rock-salt has far superior power of transmitting rays of heat. The latter, it has been found, allows 92 per cent of the total heat from any source to pass; glass only 39 per cent from a lampflame, 24 per cent from incandescent platinum, etc. Rock-salt is the only body equally diathermanous to heat from all sources. The diathermancy of the plates in every case decreases very rapidly as their thickness is increased. Research Diathermancy
In physics, photometry is the measurement of the luminous intensity of a light source, or the amount of luminous flux falling upon a surface from such a source. Photometry is important in photography , astronomy, and illumination engineering. Instruments used for photometry are called photometers. Light waves stimulate the humaneye in different degrees, depending on the wavelength of the light. Because it is difficult to make an instrument with the same sensitivity for different wavelengths as the humaneye, many photometers use a human observer. Photoelectric photometers need special collared filters to make them respond like the humaneye. Instruments that measure radiant energy instead of light are called radiometers, and must be made equally sensitive to all wavelengths. The intensity of a light source is measured in candle power, usually by comparing the source with a standard source provided by the National Bureau of Standards. The known and unknown sources illuminate portions of a window surface side by side, and their distances are adjusted until the illumination on the surface is the same. The relative intensity is then calculated from the inverse square law. Research Photometry
A radiometer is an instrument for measuring the mechanical effect of radiant energy. It consists of four crossed arms of very fine glass supported in the centre by a needle-point, and having at the ends thin pith discs blackened on one side. The instrument is placed in a glass vessel exhausted of air and when exposed to light the arms revolve. It was invented by Crookes in 1874 and forms a popular amusement today. Research Radiometer
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Transparent
