him to
explain the processes by which he pretended to transmute lead. The
stranger at last consented, and informed him, that one grain was
sufficient; but that it was necessary to envelope it in a ball of wax
before throwing it on the molten metal; otherwise its extreme volatility
would cause it to go off in vapour. They tried the experiment, and
succeeded to their heart's content. Helvetius repeated the experiment
alone, and converted six ounces of lead into very pure gold.

The fame of this event spread all over the Hague, and all the notable
persons of the town flocked to the study of Helvetius to convince
themselves of the fact. Helvetius performed the experiment again, in the
presence of the Prince of Orange, and several times afterwards, until he
exhausted the whole of the powder he had received from the stranger, from
whom it is necessary to state, he never received another visit; nor did he
ever discover his name or condition. In the following year, Helvetius
published his _Golden Calf_,[46] in which he detailed the above
circumstances.

[46] "Vitulus Aureus quem Mundus adorat et orat, in quo tractatur
de naturae miraculo transmutandi metalla." _Hagae_, 1667.

About the same time, the celebrated Father Kircher published his
_Subterranean World_, in which he called the alchymists a congregation of
knaves and impostors, and their science a delusion. He admitted that he
had himself been a diligent labourer in the field, and had only come to
this conclusion after mature consideration and repeated fruitless
experiments. All the alchymists were in arms immediately, to refute this
formidable antagonist. One Solomon de Blauenstein was the first to grapple
with him, and attempted to convict him of wilful misrepresentation, by
recalling to his memory the transmutations by Sendivogius, before the
Emperor Frederick III. and the Elector of Mayence, all performed within a
recent period. Zwelfer and Glauber also entered into the dispute, and
attributed the enmity of Father Kircher to spite and jealousy against
adepts who had been more successful than himself.

It was also pretended that Gustavus Adolphus transmuted a quantity of
quicksilver into pure gold. The learned Borrichius relates, that he saw
coins which had been struck of this gold; and Lenglet du Fresnoy deposes
to the same circumstance. In the _Travels of Monconis_ the story is told
in the following manner: "A merchant of Lubeck, who carried on but l