 Complete the following phrase:  He was prolific exhibitor, showing at least 237 photographs in the eight years from 1855 and meeting with considerable praise; he won the highest medal at the 1855 Exposition Universelle in Paris and his landscape photographs and won a gold medal at the International Exhibition in Brussels in 1856. That same year, White published a series of views of London. He also exhibited at the Manchester Art Treasures Exhibition 1857 and 