I was admiring the flood of orbital pictures that are flowing back from the Mercury Orbiter - MESSENGER. This started me thinking about what astronomers were able to see of the surface in the time of great planetary observation in the 1800's. A search of Google Books turned up some gems from the period. I found an interesting article by G.V. Schiaparelli of the Observatory of Milan entitled "Scenes on the planet Mercury" - May1890, Popular Science.
I also found some drawings representing surface features by Percival Lowell in the 1897 Monthly Notices of the Royal Astronomical Society (Vol. LVII).
Imagine what these painstaking observers, that spent hundreds of nights recording dancing visions of this far world would think if they were able to examine the digital images available to us today. Ah for a time machine!
Clear Sky - Rich