Fleurus. But, returning to more strictly scientific ascents, which began to be mooted at this period, we are at once impressed with the widespread influence which the balloon was exercising on thinking minds. We note this from the fact that what must be claimed to be the first genuine ascent for scientific observation was made in altogether fresh ground, and at so distant a spot as St. Petersburg. It was now the year 1804, and the Russian Academy had determined on attempting an examination of the physical condition of the higher atmosphere by means of the balloon. The idea had probably been suggested by scientific observations which had already been made on mountain heights by such explorers as De Luc, Saussure, Humboldt, and others. And now it was determined that their results should be tested alongside such observations as could be gathered in the free heaven far removed from any disturbing effects that might be caused by contiguity to earth. The lines of enquiry to which special attention was required were such as would be naturally suggested by the scientific knowledge of the hour, though they may read somewhat quaintly to-day. Would there be any change in the intensity of the magnetic force? Any change in the inclination of the magnetised needle? Would evaporation find a new law? Would solar rays increase in power? What amount of electric matter would be found? What change in the colours produced by the prism? What would be the constitution of the higher and more attenuated air? What physical effect would it have on human and bird life?