Downloads: From Objects to G Numbers via Index Cards

From Objects to G Numbers via Index Cards:
Helen McKearin’s Classification of Blown Three Mold Glass

Ian Simmonds.
The Glass Club Bulletin of The National American Glass Club.
Number 212, Fall/Winter 2008, pp. 12-21.
Manufactured between about 1815 and 1835, Blown Three Mold is one of the more distinctive products of early American glasshouses. (See this for further examples)   This article explains how Helen McKearin went about classifying this glass, including the role of a box of index cards which, among other things, helps reveal some important likely errors.
(download)