The speculum of Dr. Dee. He asserted that it was given him by the angels Raphael and Gabriel. It passed into the possession of the Earl of Peterborough, thence to Lady Betty Germaine, by whom it was given to the Duke of Argyll, whose son presented it to Horace Walpole. It was sold in 1842, at the dispersion of the curiosities of Strawberry Hill.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894