From a paragraph in this work, it would seem that the Baron considered his observations as tending to an explanation of the Aurora Borealis; and, since it was generally admitted that these phenomena occur within our atmosphere, that there appeared a great probability of Auroræ being visible magnetic lights. The Baron, in the original work, fully describes the Aurora Borealis; and concludes it must be similar in its nature to the flames of light seen streaming from the magnet-poles by Mdlle. Reichel and other sensitive patients of the Baron’s. It is unfortunate that these flames were only seen by certain “sensitive” persons. The drawings given of them, too, show no analogy to the magnetic curves. [Sidenote: Magnet tested for such flames.] Having the opportunity of a powerful magnet in that used during our tube-experiments, we made an attempt to detect the Baron’s magnetic flames, on or around the poles of our magnet, in a perfectly dark room. Arrangements were made to silently connect and disconnect the battery with the magnet, without the knowledge of any one except the operator. The experiment proved a complete failure; no flames or discharges of light of any kind were to be seen. The observers were five in number, two gentlemen and three ladies, but not one of the party proved “sensitive.” [Sidenote: Mr. Brooks’s experiments on action of the magnet on a sensitive photographic plate.] Some experiments made by Mr. W. Brooks, and detailed in a paper read by him before the South London Photographic Society, seem to corroborate (to a certain extent) the statements made by the Baron in regard to the influence of the magnet on a sensitive photographic plate. Remembering, however, how it has been demonstrated that light may be “bottled up” as an actinic source for a considerable period of time, it seems a question whether the images obtained were not due to some such source rather than to any magnetic aura. SUMMARY OF THE FOREGOING EXPERIMENTS AND THEIR RESULTS. [Sidenote: Summary of the experiments.] Chapter XIV. Action of magnet on glow and spectrum of Geissler gas vacuum-tubes demonstrated. Chapter XV. Action of magnet on glass capillary tube negatived. Faraday’s experiment with heavy-glass bar repeated. Chapter XVI. Action of magnet on glow in wide air-tube demonstrated. Note on stratification. In Plücker tube, action of magnet on negative pole (arc formed) and positive pole (Gassiot’s rings produced) demonstrated. Effects of magnet upon glow and spectrum of tin-chloride vacuum-tubes demonstrated. Chapter XVII. Effect of magnet upon after-glow in a bulbed phosphorescent tube demonstrated. Effect of magnet upon glow in small phosphorescent (powder) tubes examined. Marquis of Salisbury’s experiments (lighting-up with one wire only) tested, and confirmatory results arrived at. Chapter XVIII. Action of magnet on aura of electric spark demonstrated.