About this very time they invented an instrument of great delicacy, which foretold the vaster tracts of magnetism into which the earth was swinging, and measured the increase. It depended for its principle and basis on the intimate relationship between electricity and light, on the effect of magnetism upon light and upon electric radiation from the negative pole in a vacuum. They had noticed for some time that the light from any meteor or luminous body outside the sphere of influence of the earth never reached the instruments of the observers on the edge of the atmosphere quite true, and that the aberration differed at different times. By means of various experiments they came to the conclusion that the aberration was due to magnetism in the extra-terrene spaces. Their new instrument, which they called a sarmolan, they sent out into the ether beyond the earth’s atmosphere and beyond the influence of terrestrial magnetism; and, as it received beams of light from any one heavenly body towards which it had been directed, it recorded the amount of this body’s deflection from the straight course. They preferred to turn it to the moon or to Venus or Mars; for then they were sure that the deflecting masses of magnetism lay within immediate range of the earth. This sarmolan turned out to be for cosmic changes of climate what the barometer is for daily or hourly changes of weather. Whenever it recorded violent deflection, it meant that the earth was approaching an exceptionally vast tract of magnetic influence, and that there would be great and frequent disturbances for months, if not for years, in the regularity of the earth’s seasons and climates, or at least of those of one zone. It warned the Limanorans to get ready their piraknos and all other instruments they had for drawing and imprisoning for their own use the electricity from the atmosphere and the spaces above it. It was in short their cosmic barometer foretelling changes in climate years ahead. It eased the minds of the Piramo and set free half their energies for other investigations, as soon as it had proved itself a true prophet. Later improvements in it measured the distance of the supermagnetised region of space from the earth, and thus indicated the exact year and sometimes even the month and the day when the series of climatic perturbations were likely to begin. What had been guesswork before, made just before meeting the phenomenon itself, was now reduced to predictive law; and they looked forward to the time when by recording, classifying, and mapping the variations and regions of cosmic magnetism they would be able to get at the cause of its unequal distribution in interstellar space. Nay, when they had charted the great drifts and currents of varied energy that the earth encountered as its universe swung through space, they might have ready for their future voyagers to other worlds a full cosmography, which would instruct them in the kind of oceans and