Pneumatic tubes at the General Post Office; St Martin's-le-Grand.

- Image ID: HHG71F
Pneumatic tubes at the General Post Office; St Martin's-le-Grand.
World History Archive / Alamy Stock Photo
Image ID: HHG71F
Pneumatic tubes at the General Post Office; St Martin's-le-Grand. In 1888 there were upwards of 50km of tubes in London connecting the district telegraph offices and the foreign cable companies. The longest was between the GPO and the House of Commons.