LONDON.- A selection of works of art from Althorp and Spencer House (the historic London home of the Spencer family) is to be offered on 6, 7 and 8 July at Christie’s King Street and South Kensington salerooms, with individual estimates from £200 to £12 million. The sale previews are open to the public from Saturday 3 July, and offer the chance to see masterpieces by Rubens and Guercino, as well as selected contents from the attics and store rooms at Althorp and arguably the most important group of aristocratic 19th century horse-drawn family carriages that remains in existence. • The OLD MASTERS AND 19TH CENTURY ART EVENING SALE on 6 July at King Street will offer two masterpieces from the Spencer Collections; A Commander being armed for Battle by Sir Peter Paul Rubens (1577-1640) (estimate: £8