of the topic.  M. Chevreuil could find no earlier book on the twig than the ’Testament du Frere Basil Valentin,’ a holy man who flourished (the twig) about 1413; but whose treatise is possibly apocryphal.  According to Basil Valentin, the twig was regarded with awe by ignorant labouring men, which is still true.  Paracelsus, though he has a reputation for magical daring, thought the use of the twig ‘uncertain and unlawful’; and Agricola, in his ’De Re Metallica’ (1546) expresses a good deal of scepticism about the use of the rod in mining.  A traveller of 1554 found that the wand was not used—­and this seems to have surprised him—­in the mines of Macedonia.  Most of the writers of the sixteenth century accounted for the turning of the rod by ‘sympathy,’ which was then as favourite an explanation of everything as evolution is to-day.  In 1630 the Baron de Beau Soleil of Bohemia (his name sounds rather Bohemian) came to France with his wife, and made much use of the rod in the search for water and minerals.  The Baroness wrote a little volume on the subject, afterwards reprinted in a great storehouse of this lore, ‘La Physique Occulte,’ of Vallemont.  Kircher, a Jesuit, made experiments which came to nothing; but Gaspard Schott, a learned writer, cautiously declined to say that the Devil was always ‘at the bottom of it’ when the rod turned successfully.  The problem of the rod was placed before our own Royal Society by Boyle, in 1666, but the Society was not more successful here than in dealing with the philosophical difficulty proposed by Charles II.  In 1679 De Saint Remain, deserting the old hypothesis of secret ‘sympathies,’ explained the motion of the rod (supposing it to move) by the action of corpuscules.  From this time the question became the playing ground of the Cartesian and other philosophers.  The struggle was between theories of ‘atoms,’ magnetism, ‘corpuscules,’ electric effluvia, and so forth, on one side, and the immediate action of devils or of conscious imposture, on the other.  The controversy, comparatively simple as long as the rod only indicated hidden water or minerals, was complicated by the revival of the savage belief that the wand could ‘smell out’ moral offences.  As long as the twig turned over material objects, you could imagine sympathies and ‘effluvia’ at pleasure.  But when the wand twirled over the scene of a murder, or dragged the expert after the traces of the culprit, fresh explanations were wanted.  Le Brun wrote to Malebranche on July 8, 1689, to tell him that the wand only turned over what the holder had the intention of discovering. {190} If he were following a murderer, the wand good-naturedly refused to distract him by turning over hidden water.  On the other hand, Vallemont says that when a peasant was using the wand to find water, it turned over a spot in a wood where a murdered woman was buried, and it conducted the peasant to the murderer’s house.  These events seem inconsistent with Le