Batavia is a seventeenth-century cognomen for the Netherlands, to which David Gregory went in the spring of 1693, mostly to talk science with Christiaan Huygens. This document is a list of some books he wished to buy for himself and for friends back home, if he could find them. They covered Palladius, Thucydides, Dionysius of Halicarnassus, Erasmus, "all I can find of the Roman Authors at Amst[erdam]", and others. On the reverse is a list of topics he wished to discuss when he finally sat down with Huygens. These included the maths behind the famous Horologium, foliate curves, John Flamsteed's pendulum, and various topics in refraction, or "dioptrics". He refers as well to some "microscopic sphere in a flame" as well, an experiment known to scientists in Amsterdam.