Unknown. (page 479)

Hermann von Helmholtz (1821-1894), German physicist and physiologist, 1876 Unknown

Morse telegraph operating room, Cincinnati, Ohio, USA, 1859 Unknown

Workers at Nobel Explosives Company Limited, Ardeer, Ayrshire, 1884 Unknown

Laying paving slabs in a Paris street, c1900 Unknown

Dockers unloading sugar at West India Docks, London, 1889 Unknown

John Augustus Roebling, American civil engineer, 1874 Unknown

August Wilhelm Hofmann, German organic chemist, 1854-1860 Unknown

Robert Boyle, Anglo-Irish chemist and physicist and Denis Papin, French physicist, 1870 Unknown

Benjamin Franklin, American scientist, inventor and statesman, late 18th century Unknown

Darwin's study at Down House, his home near Beckenham, Kent, 1883 Unknown

Joseph Crosfield & Son's soap factory at Bank Quarry, Warrington, Cheshire, 1886 Unknown

Pierre and Marie Curie, French physicists, 1904 Unknown

Reverse of medal commemorating 50 years of cinematography by the Lumiere brothers, 1945 Unknown

Webb's chemical factory, Diglis, Worcestershire, 1869 Unknown

Isaac Newton, English mathematician and physicist Unknown

Marie Curie, Polish-born French physicist, in her laboratory, 1912 Unknown

Joseph Wilson Swan, British physicist and chemist, demonstrating electromagnetism, 1889 Unknown

Hypnotised subject in a state of catalepsy, 1891 Unknown

Bodyguard of Persian Kings, 6th-5th century BC Unknown

Air raid damage, Clacton-on-Sea, Essex, World War II, April 1940 Unknown

Hawker Hurricane in flight, Battle of Britain, World War II, 1940 Unknown

Isaac Newton, English scientist and mathematician, 1874 Unknown

Nurse examining children before 'cleansing', Chaucer Cleansing Station, London, 1911 Unknown

Workmen extending tramlines, Brixton Road, London, 1907 Unknown

Traffic at Piccadilly Circus, London, 1912 Unknown

Savory & Moore's Pharmacy, 143 New Bond Street, London, 1912 Unknown

Carts outside the Sundial public house, Goswell Road, London, 1900 Unknown

Firemen lined up outside Bishopsgate Fire Station, Bishopsgate, City of London, 1908 Unknown

Railway bridge and advertising over the Brixton Road, Lambeth, London, 1938 Unknown

Constructing a piano, Benthal Road Evening Institute, London, 1914 Unknown

Dancing around the maypole, Hugh Myddelton School, Finsbury, London, 1906 Unknown

Relaxing in the Social Hall, Cosway Street Evening Institute for Women, London, 1914 Unknown

Fire engines at Cannon Street Fire Station, City of London, 1913 Unknown

Men laying tramlines in the middle of the road, Whitechapel High Street, London, 1929 Unknown

Line of taxis, Abingdon Street, Westminster, London, 1933 Unknown

Cart laden with sacks, Mansell Street, Stepney, London, 1914 Unknown