THE EVOLUTION OF ILLUSTRATION PRACTICES IN GEOLOGY TEXTS DURING THE GOLDEN AGE OF GEOLOGY (1788-1840)
The graphic density of published texts changed noticeably within the Golden Age of Geology. In the earliest publications, illustrations were used sparingly, if they were present at all. The popular use of wood engravings in the later texts allowed easier and economical reproduction of graphic images; texts published late in the age of focus tended to have more illustrations than texts published at the beginning. Hypothesis testing around a correlation coefficient showed significance at the 99% confidence level for a relationship between the publication year and the graphic density of texts.
Further research into the history of publishing revealed that the illustrative trends paralleled but lagged innovations in the printing industry. Changes in illustration type also reflected societal changes of an emerging educated class as well as changes within the targeted audiences for geology texts.
Although the inclusion and types of graphics evolved substantially in the formative years of geology as a separate science, illustrative design had not yet reached its present level as far as complexity, layering of data, and causality. Even at the end of the Golden Age of Geology, most illustrations were non-mathematical, and indicate that geology was still in a pre-graphing phase.