The original paper pages for these sketches are available online as a PDF file.
The following is background information from Geoff Gaherty about the Montreal Centre's Mars observations, in response to a question about the significance of the numbers in the top left and right corners of each page in the PDF file.
I've downloaded the PDF file, and gone through it. I was actually the person who put that file together back in 1961, and added the numbers in the corners! I honestly can't remember what the left-hand numbers signify, but it will probably come back to me. The right hand numbers are a sequential numbering of all the drawings of Mars submitted by everyone in the centre for that apparition. The drawings in the PDF are drawings which I selected as being of the highest quality by experienced observers, to form the basis of my map.
You have to remember that this was in pre-computer days, so I had to organize things manually. My primary objective was to prepare a map based on our observations. This was partly for purposes of my report (which may have appeared in the Journal), and partly as a term project for a course in cartography which I was taking at McGill that spring. I originally had grand plans to project the drawings onto a sphere to obtain longitudes and latitudes, but gave up on that. What I did was to use an ALPO map from the previous apparition as a base, and draw my map using positions on that map, but detail from our drawings. To do that, I needed to sort the drawings by central meridian, which is how they are arranged in the PDF. However, I thought I might need to put them back in chronological order at some point, so, before sorting them by CM, I numbered them in chronological order in the upper right corners. So your surmise about this being an index is correct. However, for purposes of study, the present arrangement by CM is the best.
These are the drawings selected as the best; the rest are primarily by beginners made at an observing night at the observatory where everyone lined up and took their turn at the eyepiece of the 6-inch refractor. Most of these are pretty awful, and probably not worth preserving! [Any such sketches are included in the PDF file, but not in the online sketch gallery.]
RASC Planetary Section Bulletins from the 1960s.
Sketcher Spotlight: Ted Morris
Ted was a mathematical physicist at McGill whose lasting claim to astronomical fame was identifying several of the "missing Messiers." He was also the second graduate of the Messier Club, making him one of the very first people in the whole world in the 20th century to observe all the Messiers.—GG [Sketches by Ted]
A note from Klaus Brasch (May 2013):
I think it fair to say that we were all still influenced somewhat by the "Lowellian paradigm" in those days and maps like those of Slipher and indeed many others at the time all showed diffuse streaks like those in my drawing. We referred to them as "canals" because they were labeled as such on those pre-Mariner charts. We had long ago given up the idea that they were actual Lowellian irrigation canals, and considered them more like borders between area[s] of different color, brightness or contrast.