There is one condition indispensable to this purging-process: the atmosphere must be still and warm. Should it rain, the Geotrupes will not stir out of doors. They have sufficient resources underground for a prolonged holiday. Should it be cold, should the north-wind blow, they will not sally forth either. In both cases my cages remain deserted on the surface. We will leave out of the question these periods of enforced leisure and consider only those evenings on which the atmospheric conditions are favourable to foraging-expeditions, or at least seem to me as though they ought to be. I will summarize the details in my note-book in three general cases. First case. A glorious evening. The Geotrupes fuss about the cages, impatient to hasten to their nocturnal task. Next day, magnificent weather. The prophecy, of course, is of the simplest. To-day’s fine weather is only the continuation of yesterday’s. If the Geotrupes know nothing more than this, they hardly deserve their reputation. However, let us pursue the experiment before drawing any conclusions. Second case. Again a fine evening. My experience seems to say that the condition of the sky forebodes a fine morning. The Geotrupes think otherwise. They do not come out. Which of the two will be right, man or Dung-beetle? The Dung-beetle: thanks to the keenness of his perceptions, he foresees, he scents a downpour. Rain comes during the night and lasts for part of the day. Third case. The sky is overcast. Will the south-wind, gathering its clouds, bring us rain? I am of that opinion, appearances seem so much to point that way. The Geotrupes, however, fly and buzz around their cages. Their prophecy is correct and I am wrong. The threat of rain is dispelled and the sun next morning rises radiantly. They seem to be influenced above all by the electric tension of the atmosphere. On hot and sultry evenings, when a storm is brewing, I see them moving about even more than usual. The morrow is always marked by violent claps of thunder. There you have the upshot of my observations, which were continued for three months. Whatever the condition of the sky, whether clear or clouded, the Geotrupes announce fair weather or storm by their excited movements in the evening twilight. They are living barometers, more worthy of belief perhaps, in such contingencies, than the barometer of our scientists. The exquisite sensitiveness of life is mightier than the brute weight of a column of mercury.