Mr. Glaisher's circumstantial evidence of the height he reached has been assailed lately, partly from his assumption that the velocity of the balloon while rising and falling during the thirteen minutes was uniform, but principally from the supposition that men could have survived in that region of death, without at least artificial means of respiration. While it is certain that Berson's observations, which are described later, were made at a greater height than Glaisher's, yet all credit must be given to this Nestor of aeronautical and meteorological science in Great Britain, who is still living at the advanced age of ninety. The example of Glaisher was not followed in England, but it stimulated interest in the balloon again in France, where MM. Flammarion, de Fonvielle, and Tissandier have made many ascents for scientific purposes, and have presented the results in a popular form to the public. Photography in a balloon is generally a failure on account of the intense reflection from the upper cloud surfaces and the haze which masks the earth. Consequently, for scenic effects we must rely upon sketches, of which those in that interesting, but now rather rare book, _Travels in the Air_, may be referred to. The high atmosphere is often filled with fine ice crystals which, though invisible from below, occasion curious optical phenomena, and some of these have been sketched by M. Albert Tissandier, who has the advantage of being an artist as well as an aeronaut. Of the many narratives of balloon voyages, one of the most thrilling is the tragedy of the _Zenith_. In 1875, through the co-operation of the French Academy of Sciences and other scientific bodies, it was arranged to make two voyages, one of long duration, the other to a great height, in the balloon _Zenith_. The long voyage from Paris to Bordeaux was successfully accomplished in twenty-four hours, and on April 15 the _Zenith_ again rose from Paris, carrying MM. Gaston Tissandier and CrocÈ-Spinelli, with Sivel as aeronaut. By the advice of M. Paul Bert, the distinguished physiologist, three small balloons of oxygen were provided to assist respiration. The scientific apparatus was as follows: a pump was arranged to draw air through tubes filled with potash in which to store the carbonic acid at different heights in the atmosphere, in order that analysis might determine if its proportion diminished at great heights; a spectroscope was employed to examine the line of water-vapour in the atmosphere, and two aneroid barometers were provided, one giving the pressure corresponding to heights up to 13,000 feet, the other the pressure between 13,000 and 30,000 feet. There were also two barometric tubes registering the lowest pressure, as well as thermometers and other scientific instruments. At 15,000 feet the voyagers began to breathe oxygen, which had been used beneficially by Sivel and CrocÈ-Spinelli in a high ascent the previous year. At 24,000