It is fairly well understood that space weather's first impact on human technology was on telegraph systems [Barlow, 1849]. But when did this first occur? The global impacts from the August–September 1859 geomagnetic storms are certainly well documented, and even earlier storms (e.g., March and September 1847, September 1851) caused problems regionally in Great Britain and elsewhere for this new technology [Prescott, 1860]. While 1847 is generally recognized as the year of the first space weather impact on the telegraph [Prescott, 1860; Boteler et al., 1998; Siscoe, 2007], it appears that even at earlier times, during the first commercial uses of the telegraph, problems were experienced.
The Cooke-Wheatstone telegraph was one of the first telegraph systems to be used commercially [Prescott, 1860]. First deployed in 1838 in England, it was used as an indicator of clear rail lines for railway switching. In the issue of the journal Nature (1871), on page 441, the following account appears:
“On the 18th of October, 1841, a very intense magnetic disturbance was recorded, and amongst other curious facts mentioned is that of the detention of the 10.5 P.M. express train at Exeter [England] sixteen minutes, as from the magnetic disturbance it was impossible to ascertain if the line was clear at Starcross. The superintendent at Exeter reported the next morning that someone was playing tricks with the instruments, and would not let them work.”
Although we are not told the instrument in use, the one and two-needle Cook-Wheatstone telegraphs were in use at the time and so are most likely the ones mentioned. Despite the lack of other corroborating information, this appears to be the first recorded space weather impact on human technology—making the Exeter train late by sixteen minutes on 18 October 1841.