This was by far the most attractive group of chambers for us. Not only could we test the wonderful instruments for ourselves; but we could examine by aid of magnifiers the graphic results of their observations automatically recorded as if by photography. We could minutely study the flight of sea birds not visible to the naked eye. The babel of sounds that went on in the cities of the archipelago quite beneath the horizon we could hear like a great roar beside us when we placed the sonoscripts in the sound-magnifier; and with the aid of its analyst we could unravel the sounds by repeating them slowly. Though I had not my electric sense sufficiently developed to feel the differences in the starry impulses when the electrographs were placed in the electro-magnifier, I could distinguish their differing degrees of force, and I could see how much Thyriel appreciated the fine shades of variety in the impulses. We were engaged in testing the electric records, when we could see the observer of the tremolan bustling from table to table and map to map, whilst his pupil watched the indicator. His excitement spread into the adjoining chambers, and their occupants, leaving their instruments to assistants, came to his aid. There was an inexplicable electric disturbance on the north-east shore of the island; the field in that direction was agitated. They ran to the idrolan and turned it to the north-east; at once they knew that some seven or eight hundred miles off there was advancing at a rapid rate a great wave of electric disturbance. We all recognised a growing sultriness of heat in the profound calm of the atmosphere even at those icy heights. No time was to be lost. All the members of the Lilamo were called up, and in a few minutes were assembled in the observatory.