Caption: Three of Percival Lowell's (1855--1916) less elaborate drawings of Mars.

Features:

1. The top two drawings are similar to, but do NOT seem to be, two drawings in Lowell's book Mars (1895). The lower drawing is from Mars (1895).

2. The drawings show the Martian canals---the thin, nearly straight lines. The Martian canals were NOT real. They were optical illusions.

3. The drawings were all done using visual astronomy. Astrophotography was available in the late 19th century, but Lowell and others claimed that it was too long exposure to capture the flickering images that the human eye could capture. There may be some truth to this, but, in fact, the Martian canals Lowell and others drew were optical illusions---as aforesaid---though some may correspond to real features of some kind. Many astronomers of Lowell's time did argue that the Martian canals were optical illusions. But Lowell riposted that he had a great observing site at the Lowell Observatory in Flagstaff, Arizona (which was true), and so could see Martian canals that others could NOT see (which was NOT true).

4. The dark regions on the drawing may be real. Lowell certainly could make out real dark regions on Mars as did earlier observers going back to Christiaan Huygens (1629--1695) in the 17th century. But without more information, Yours truly CANNOT identify Lowell's dark regions with anything yours truly can see on a modern Mars geographic map. One could try to look up what features Lowell was trying to represent---but yours truly is too lazy.

5. Actually, the coloring on Mars varies a bit with the covering of Martian dust which changes with wind and wind storms. So light and dark regions are NOT completely fixed.

Images:

1. Credit/Permission: Percival Lowell (1855--1916), before 1914 (from Yakov Perelman (1882--1942), Distant Worlds, St. Petersburg, Soykin Printing House, 1914; uploaded to Wikipedia by Boleslaw Niemen-Anton Kitaycev (AKA User:Boleslav1), 2006) / Public domain.
   Image link: Wikipedia: File:Lowell Mars channels.jpg.
   
2. Percival Lowell (1855--1916), Mars (1895) / Public domain.
   Download site: Eric Hutton's site Mars by Percival Lowell (1895): see Plate I: Mars, Sinus Titanum, frontispiece.
   Image link: Itself.