Temple may have used on that night one of the medieval incantations, or possibly the more ancient invocation of the Isiac rite with which a man of his knowledge and proclivities would certainly be familiar.

The accessories of either are sufficiently hideous to weaken the mind by terror, and so prepare it for a belief in some frightful apparition.

But whatever was done, I feel sure that the music of the _Gagliarda_ formed part of the ceremonial.
Medieval philosophers and theologians held that evil is in its essence so horrible that the human mind, if it could realise it, must perish at its contemplation.

Such realisation was by mercy ordinarily withheld, but its possibility was hinted in the legend of the _Visio malefica_.
The _Visio Beatifica_ was, as is well known, that vision of the Deity or realisation of the perfect Good which was to form the happiness of heaven, and the reward of the sanctified in the next world.

Tradition says that this vision was accorded also to some specially elect spirits even in this life, as to Enoch, Elijah, Stephen, and Jerome.