Richard Houston ( 1721 - 1775 ) was an Irish painter. Richard Houston s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 13.45 USD for Caroline, Duchess of Marlborough in 2004 to 4649.61 USD for The Four Elements: Earth; Air; Fire; and Water in 2008 , based on the size and medium of the artwork.