There are a great many very wonderful appearances in a polar sky, besides the Aurora Borealis. Perhaps the most remarkable of these are Parhelia, or "mock suns," which are often seen to shine in various parts of the sky. As many as six of them are sometimes seen at once, all shining with great brilliancy. They are generally brightest just before day-break, and fade away as the true sun ascends. Parhelia have also been seen at different times on the continent of Europe. At Marienberg, in Prussia, many years ago, towards evening, one Three at once were seen at Sudbury, in Suffolk, and two were seen in a part of Rutlandshire. There are recorded many other appearances of this remarkable phenomenon, but they do not seem to differ much from each other. There is great uncertainty as to what occasions these mock suns. Perhaps they are merely reflections of the image of the true sun upon reflecting clouds, such as I shall describe to you presently. The circumstance that seems to render this probable, is that they sometimes become brighter as the sun approaches them, which cannot easily be accounted for by supposing them to have any source of light in themselves. On the contrary, their fading away at times as he rises, may be occasioned by the clouds on which they are reflected, becoming The name Ignis Fatuus, or False Fire, is applied to a flickering, bluish light, which is often seen in marshy districts, and in damp burial grounds, either on the surface of the earth or only a small distance above it. So you see it is not strictly a wonder of the sky; but I introduce it here because it seems to be somewhat similar to some of the higher meteors, in the manner in which it is occasioned. A great many entertaining stories are told of persons having mistaken these Ignes Fatui for real lights, and it is said that benighted travellers I will presently tell you how you can try a simple experiment, that will go a great way towards accounting for these idle Will-o'-the-Whisps. The inflammable gas called Hydrogen, is copiously produced by the decomposition of animal and vegetable bodies. The substance called Phosphorus, is contained in animal bodies, and is set at liberty in small quantities by their decomposition. When phosphorus and hydrogen come together under certain circumstances, they There is, therefore, no difficulty in supposing that most marshy grounds may produce this gas; and this experiment will show that it is very likely that the Will-o'-the-Whisp is nothing more. Hydrogen may be obtained by pouring diluted Sulphuric acid on small pieces of Iron or Zinc. If you mix very small pieces of Phosphorus with very small pieces of Zinc, and put them into a glass, and pour over them the acid, Phosphuretted Hydrogen will be sent off, and the surface of the acid will be covered with a beautiful blue flame of the very colour of the Ignis Fatuus. The cause of the flame is, that the phosphuretted hydrogen is so wonderfully inflammable, that the moment it comes into air of a common temperature, it bursts into flame. If you try this experiment, you will see how likely it is that the Will-o'-the-Whisp is an escape of this gas from the surface of the earth. |