The book by Heinrich Hensoldt is fiction. He claimed in the mid-1890s to have visited Ceylon and India, but was soon discredited. Hensoldt was originally from Wetzlar, Germany, a son of Moritz Wetlar, a well known maker of microscopes and telescopes. He may have based his information on Warkus from actual knowledge, but I wouldn't trust him. Sorry, and good luck with your hunting.