Thomson (or someone at least) wrote “Morning” on the back of this sketch. Maybe someone can tell me who? The list of possible "signers" is short. Thomson? MacCallum? Harris? Maybe even J.E.H. MacDonald?
Tom’s motivation to “record” this particular observation certainly had to be the colours of the hills and the cloud structure.
In addition, this has got to be morning! Tom said it was morning. God bless him for helping out because I am not certain I could have deduced this from looking eastward to the rising morning sun or westward toward the setting late afternoon sun.
The sun is certainly just behind the purple hills in the distance as the horizon is brightest there. The crepuscular rays also confirm this and converge back to the sun as their source. The crepuscular rays do not diverge very much so Tom is looking upward at the “train track shadows”. If the sun was behind the clouds, the crepuscular rays would diverge much more as if you are laying at train track level looking directly toward the oncoming train. The relatively parallel nature of the crepuscular rays confirms that the sun is below the horizon.