Without the Patchouli essential oil in the mix, the Lemongrass scent would disappear quickly.
Do you think that it is possible that only base of the original perfume survived?
I don't know enough about the science behind this question. Unlike perfume, soap goes through saponification so it may have a different effect on what trace elements would be left behind.
I do know that if I made a
bar of soap with just Lemongrass oil without a base oil to
anchor the scent, in 3-6 months the
bar of soap would have no smell at all. Amazing considering how potent Lemongrass is when you smell it.
I have bars made 5 years ago with Patchouli and Lemongrass that
still retain the Lemongrass smell making the ancient people all the more impressive to me.