Rensselaer Republican, Volume 16, Number 28, Rensselaer, Jasper County, 20 March 1884 — PROF. TYNDALL ON RAINBOWS. [ARTICLE]

PROF. TYNDALL ON RAINBOWS.

The Canae of am Interesting Phenomenon Explained. Lecturing at the Royal Institution on thd above subject, Prof. Tyndall observed that the oldest historical record' of a rainbow was found in the “I do set My bow in the cloud, and 4t shall be for a token of a covenant between me and the earth.” The sublime' conception of the theologian preceded that desire for exact knowledge which was characteristic of the men of science. Whatever the ultimate cause of the rainbow might have been, the proximate cause was physical, and the aim of science had been to refer the rainbow to its physical principles. Progress toward that consummation had been veiy slow. Slowly the ancients mastered tile laws of reflection; still more slowly were the laws of refraction dug from the quarries in which nature had imbedded them. He used that language because the laws were incorporate in nature before they were discovered by men. It was by the scientific genius of the Dutchman Snell that the world obtained in 1621 the first approximate explanation of the rainbow, his discovery having, however, been rendered possible by the observations and measurements of earlier philosophers. The great Descartes completed the solution. There was a certain form of emotion called intellectual pleasure excited by poetry, literature, nature, and art, but he doubted whether there was any pleasure of the intellect more pure and concentrated than that of the scientific man who, looking at a difficulty which had challenged the human mind for ages, saw that difficulty melt before his eyes and become crystallized as a law of nature. Such pleasure must have been that of Descartes when he sueeeeded in uncovering the law which rules the most splendid meteor of our atmosphere. Since Descartes’ time further light had been thrown on the matter by Newton, who found out the secret of the colors of the prisms; by Thomas Young, who, eighty-two year's ago, was appointed Professor of the Royal Society, and who discovered the causes of the rainbow’s supernumerary zones; by Sir George Airey, the late Astronomer Royal, who demonstrated the truth of Prof. Young’s scientific principles by more accurate calculations; and lastly, by the late Prof. Miller, of Cambridge,: and Dr. Caller, of Berlin. Prof. Tyndall described how, in the Alpß, last year, and subsequently at Hindhead, in Hampshire, he had witnessed the rare phenomenon of a white rainbow, caused by reflected light on a misty atmosphere. 1 By clever and amusing experiments the lecturer showed how this remarkable effect might Ire artificially produced, and how, when the moisture in the air was composite, as, for instance, where water spray was mixed with paraffin oil spray, a still more wonderful rainbow resulted, such as was to be seen at almost all times from a famous mountatn in Western China, whither the people flocked from far and near to witness what they called “The glory of Buddha. —London Telegraph.