[Irish censuses 1642-1910] Incomplete series of slides produced by Thomas Holmes Mason for [Sir William John Thompson for a talk on Irish censuses]. Slides have small circulate labels with a number in red ink [indicating their position in the series]. The slides seemed to have accompanied a talk on the Irish censuses between 1642 and 1901, pulling out statistical details on various themes including birth rate, literacy, housing and population density. Slides are housed in their original wooden box. [1910s]