The Trouvelot astronomical drawings manual, by Étienne Léopold Trouvel 68394 [Full title: The Trouvelot astronomical drawings manual] [Full author's name: Étienne Léopold Trouvelot] [Author: Étienne Léopold Trouvelot] [Link: https://www.gutenberg.org/6/8/3/9/68394] [Files: 68394-0.txt; 68394-h.htm] Thanks to Laura Natal Rodrigues (Images generously made available by Hathi Trust Digital Library and Wikipedia Commons.) Regards, Al