Specimen bottle of crystalline sodium nitrate

In the 19th century nitrogen-rich salts were mined from Chile for the fertiliser industry. Like guano – the other main natural source of nitrogen for fertilisers – these minerals had been so intensively extracted that they were nearly exhausted by 1900.

Object 5: Jar of Chilean nitrate

1862

Nitrogen-rich salts were mined from Chile for the fertiliser industry. They replaced guano as the main natural source of nitrogen for fertilisers. But in 1898 scientist William Crookes warned that supplies of these minerals would not keep up with demand. It seemed the only answer was for chemists to find an easy way to extract nitrogen from the air.

Lent by Wellcome Trust

Object no. A603259

In the 19th century nitrogen-rich salts were mined from Chile for the fertiliser industry. Like guano – the other main natural source of nitrogen for fertilisers – these minerals had been so intensively extracted that they were nearly exhausted by 1900.