The Opake Solar Microscope Compendium, by Dudley Adams, London, is fully described in George Adams II's Essays on the Microscope of 1787. It is therein acknowledged that, despite the name, this refinement of the solar microscope was in fact introduced in 1774 by his rival Benjamin Martin, who stated that: "with this instrument all opake objects, whether of the animal, vegetable or mineral kingdom, may be exhibited to great perfection, in all their natural beauty; the light and shades, the prominences and cavities, and all the varieties of different hues, tints and colours heightened by the reflection of the solar rays condensed upon them". In effect, this was the sort of leisure time entertainment that would be replaced by the magic lantern and later the cinema, as the opake box is in effect a small camera obscura which, by means of affixing it to the body cone of the solar microscope, could project into an otherwise darkened room, an image of whatever specimen one chose to place in the sprung retainer - a technical revolution in the history of projection.