'The Falls of Niagara', 1849.
© Science Museum / Science & Society Picture Library
Colour engraving by Josiah Wood Whymper taken from 'Phenomena of Nature', published in London in 1849 for the Society for Promoting Christian Knowledge. 'Niagara is a large river of North America uniting Lake Erie with Lake Ontario. The difference in level between these lakes is 334 feet, and the greatest sudden drop between the two occurs at Niagara on the border between Canada and the United States of America. The thunder of Niagara Falls is so loud it has been heard at a distance of forty-six miles.'