648 PRESIDENTIAL ADDRESS [443 have sometimes pointed out that if during the long hours of seances we could keep the devil occupied in so comparatively harmless a manner we deserved well of our neighbours. A real obstacle to a decision arises from the sporadic character of the phenomena, which caunob be reproduced at pleasure and submitted to systematic experimental control. The difficulty is not limited to questions where occult influences may be involved. This is a point which is often misunderstood, and it may be worth while to illustrate it by examples taken from the historjr of science. An interesting case is that of meteorites, discussed by Sir L. Fletcher, formerly Keeper of Minerals in the British Museum, from whose official pamphlet (published in 1896) some extracts may be quoted:—"I. Till the beginning of the present [i.e. 19th] century, the fall of stones from the sky was an event, the actuality of which neither men of science nor the mass of the people could be brought to believe in. Yet such falls have been recorded from the earliest times, and the records have occasionally been received as authentic by a whole nation. In general, however, the witnesses of such an event have been treated with the disrespect usually shown to reporters of the extraordinary, and have been laughed at for their supposed delusions: this is less to be wondered at when we remember that the witnesses of a fall have usually been few in number, unaccustomed to exact observation, frightened by what they both saw and heard, and have had a common tendency towards exaggeration and superstition." After mention of some early stones, he continues : "3. These falls from the sky, when credited at all, have been deemed prodigies or miracles, and the stones have been regarded as objects for reverence and worship. It has even been conjectured that the worship of such stones was the earliest form of idolatry....The Diana of the Ephesians, ' which fell down from Jupiter/ and the image of Venus at Cyprus appear to have been, not statues, but conical or pyramidal stones." " 5. Three French Academicians, one of whom was the afterwards renowned chemist Lavoisier, presented to the Academy in 1772 a report on the analysis of a stone said to have been seen to fall at Luce* on September 13, 1768. As the identity of lightning with the electric spark had been recently established by Franklin, they were in advance convinced that 'thunder-stones' existed only in the imagination; and never dreaming of the existence of a ' sky-stone' which had no relation to a ' thunder-stone,' they somewhat easily assured both themselves and the Academy that there was nothing unusual in the mineralogical characters of the Luc6 specimen, their verdict being that the stone was an ordinary one which had been struck by lightning." " 6. In 1794 the German philosopher Chladni, famed for his researches into the laws of sound, brought together numerous accounts of the fall offuse to have anything to say ta them. Is—(i.e. believers).