潭影录 Prof Tilak of Ruhuna University, Sri Lanka 2017-04-23 Gan Zhang On April 23 we met Professor Tilak of Ruhuna UNiversity of Sri Lanka, who has been our main collaborator and has taken care of our work in Srilanka for the last nearly 2 years. He is a hydrorlogist /geochemist. (pictures by: Wu Manqing)