On this date, Professor Geoffrey T. Martin together with Dr. Jacobus Van Dijk representing the Leiden museum discovered the burial chamber of Maya's subterranean tomb at Saqqara some 18 metres (60 feet) below the surface.

In 1839 Humbert died in Italy, bequeathing his private collection of antiquities to the Leiden museum.

He became assistant to Coenraad Jacob Temminck at the Leiden museum.

His scientific work in the Leiden museum continued until his death and his collection is conserved in Naturalis.

During the expedition Rottiers organizes a small excavation on Melos, makes an elaborate study of the medieval architecture on Rhodes, and eventually does deliver antiquities to the Leiden museum in several shipments.

And his good friend Ger van Wengen, who devoted his time as curator at the Leiden ethnological museum to popularizing ethnology, with Ger using data provided by Hans, such as his book De schending van Soebadra (The abduction of Subadra), and Hans learning from Ger.

Afterwards he continued his studies as an associate of the Leiden museum, spending most of his days in the building at the Raamsteeg and later at the Darwinweg in Leiden, where he continues to study and publish on Mollusca and other topics.

As part of his duties at the Leiden museum he worked in other fields for instance on Decapoda.

A selection of articles by G.F. Mees for the Leiden museum, Repository.