Ferrers purchased the painting for Â # 210 , but the 6th Earl sold it at an auction . It is now held by Derby Museum and Art Gallery as its permanent display . Ferrers purchased the painting for Â # 210 , but the 6th Earl auctioned it off , and it is now held by Derby Museum and Art Gallery , where it is on permanent display , and close to a working replica of a full-sized mechanical Grand Orrery .