I’ve been down an internet rabbit hole with this one.

I was reading Peter Hopkirk’s ‘Trespassers on the Roof of the World’, which summarises the adventures and misadventures of late nineteenth and early twentieth century travellers to Tibet, which for much of that time was closed to outsiders, when I came across a reference to ‘self- heating soup’.

The reference was in an account of Sir George Littledale’s expedition in 1895, and I was astounded that they had self heating soup in 1895.

So first of all I checked Google Books to check we didn’t have a transcription error

which was a little bit problematical as the search didn’t bring up the Littledale’s own account of the journey.

However I tracked down a searchable full text version of the Littledale’s own account of the journey and there it was

Silver’s self boiling soups, which are also described as self heating elsewhere in the text.

This is quite interesting as self heating cans were not supposed to have been invented until 1897 by the Russian engineer Yevgeny Fedorov, yet the Littledale’s had some self heating soup in 1895.

Unfortunately I could not trace any information about Silver’s self-heating soups, and how they worked.

I’m guessing that, like contemporary self heating cans you broke a seal allowing two chemicals to mix and generate an exothermic reaction, a bit like these disposable single use handwarmers you see for sale in ski shops.

The interesting thing is that they seem to have dropped out use.

I couldn’t find any record of any of the early twentieth century Antarctic explorers using them, but apparently Hiram Bingham used them during his expeditions in Peru around 1910.

Strangely, searching Trove, I did find an article in the Cobram Courier of 25 March 1915 on self heating cans, where they were described as a ‘new Yankee invention’, even though they had been around for almost twenty years.

Self heating soups had their heyday during world war two, when the allies issued their soldiers with cans of self heating soup. These cans worked slightly differently from current self heating cans with a compartment filled with a mixture of iron oxide and aluminium in the middle of the can, and a magnesium fuse.

Inert until the fuse was lit, the iron oxide mixture reacted to give an exothermic reaction to heat the soup.

I couldn’t find an example of a self heating soup can, but the Scott Polar Research Institute’s museum does contain two self heating cans of cocoa that work on the same principle