Copies: one formerly Richard Green, London (panel, 55.8 x 96.5), another Marseille, Mus. des Beaux-Arts. Those are the two copies listed by Ertz and the Green one might duplicate one of those below: copy by Jan the Younger (according to Ertz) sold London (Christie's April 7, 1995 lot #11). A seriously feeble copy of this Air with other elements that don't exactly match rest of this set sold London (Sothebys 8.vii.99 #54, o/copper 42.5 x 58). There are photographs of numerous other copies at RKD: Askol Trust (??); one sold London (Christie's June 23 1967 # 8) (panel, 56 x 96), one in bad shape sold London (Sotheby's April 4, 1984 lot #47) (panel, 56 x 96.5), awful copy attributed to Jan the Younger & van Balen sold London (Christie's May 23, 1986 #97 (panel, 55.3 x 89.5)). Copy sold London (Sotheby's April 18, 2002 #16 (panel, 54.5 x 94)) as Jan the Younger and Van Balen (seems pretty decent though damaged). This Doria Pamphili picture and the Lyons version are close to identical, although the Lyons one has some brightly-colored birds that are not in this one. Why would that be? And oddly, the Birds of Paradise here seem to have no legs. Surely he knew better by this time, or perhaps not in fact. Preparatory drawing in Braunschweig, Herzog Anton-Ulrich Museum, Inv. # K.K.79 (see Winner 1972). This is related to all of the Air compositions yet is exactly followed in none of them. There is also a sketch in Dresden, Kupferstich-Kabinett, that Winner does not accept (1961 p.231). Moreover there is a sheet in the van Regteren Altena collection in Amsterdam that seems related to an unrealized telescope there is here just grabbing a bird.