Readers reply: why haven’t we invented a way to record and play back smells?

The long-running series in which readers answer other readers' questions on subjects ranging from trivial flights of fancy to profound scientific and philosophical concepts

I imagine that a couple of hundred years ago the idea of recording and playing back audio or video was as ridiculous as the idea seems now of recording and playing back odours. So why have we made so much progress at the first but none at the second? Peter Keyston, Newton Blossomville

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