TN Francisco Goya y Lucientes, the centenary of whose death is being celebrated this year, Spain possessed one of the few great painters that the eighteenth century produced. Born in 1746, he lived through the days of Spain's decline and the Napoleonic invasions, and his pictures form a vivid record both of the personalities and of the manners of the day. Mr. Isherwood Kay , who will talk on his work tonight, is a lecturer at the National Gallery and the author of the Burlington monograph on Spanish Art.