Oak is a great suggestion. I'll have to try that one. The one that gets me is fresh hemp rope. It smells like...well...you have to smell it. Old cow chips, maybe? It definitely has a barn smell, but the earthy quality of most hemp, linen and wool is enough to give you an authentic smell, but you can add several other period smells to the mix. Beeswax from candles. Coal from the cook's stove (and as a very common fuel for heating in London and elsewhere). Vinegar from the stores. Aromatics proscribed by doctors as healing smells, such as essence of rose, aloe, etc.