[cacher]
from Whymper, E, 1884, Coloured sky observed during eruption of Cotopaxi, in Nature, vol 29
pp199-200, London, Macmillan:

"On July 3, 1880, I was engaged in an ascent of Chimborazo, and was encamped on its western side at 15,800 feet above the sea. The morning was fine...we saw to our north the great peak of Illiniza and 20 miles to its east the great peak of Cotopaxi, both without a cloud around them, and the latter without any smoke issuing from its crater - a most unusual circumstance; indeed, this was the only occasion on which we noticed the crater free from smoke during the whole of our stay in Ecuador. ...
At 5:45 A.M. a column of smoke of inky blackness began to rise from the crater. It went straight in the air, rapidly curling, with prodigious velocity, and in less than a minute had risen 20,000 feet above the rim of the crater. ...
We knew that we saw from our station the upper 10,000 feet of the volcano, and I estimated the height of the column of smoke at double the height of the portion seen of the mountain. The top of the column was therefore nearly 40,000 feet above the sea. At that elevation it encountered a powerful wind blowing from the east, and was rapidly borner for 20 miles toward the Pacific, seeming to spread veryl slightly and remaining of inky blackness, presenting the appearance of a gigantic inverted L, drawn upon an otherwise perfectly clear sky. It was then caught by a wind blowing from the north, and was borne toward us, and appeared to spread rapidly in all directons. As this cloud came nearer and nearer, so, of course, it seemed to rise higher and higher in the sky, although it was actually descending. Several hours passed before the ash commenced to intervene between the sun and ourselfes, andwhen it did so we witnessed effects which simply amazed us. We saw a green sun, and such a green as we have never, either before or since, seen in the heavens. We saw pataches or smears of something like verdigris green in the sky, and they changed to equally extreme blood reds, or to coarse brick-dust reds, and they in an instant passed to the color of tarnjished copper or shining brass.. Had we not known that these effectes were due to the passage of the ash we might well have been filled with dread instead of amazement; for no words can convery the faintest idea of the impressive appearance of these strange colors in the sky, seen one minute and gone the next, resembling nothing to which they can be properly compared, and surpassing in vivid intensity the wildest effects of the most gorgeous sunsets."

[cacher]
"Bombs fell as far as La Cienega (22 km SW from the crater) and Tanicuchi (24 km SW from the crater)" (Pistolesi et al, 2011).
Note: the "bombs" described refer only to the large size (>64 mm diameter) of tephra fragments deposited as fall-out from the eruption column. They are not classic ballistic ejecta (it is physically impossible to eject bombs that far on a ballistic trajectory).
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Sources:
- Barberi et al (1995) "Chronology and dispersal characteristics of recently (last 5000 years) erupted tephra of Cotopaxi (Ecuador): implications for long-term eruptive forecasting", Journal of Volcanology and Geothermal Research, v 69 (3-4), pp. 217-239
- Pistolesi et al (2011) "Physical volcanology of the post–twelfth-century activity at Cotopaxi volcano, Ecuador: Behavior of an andesitic central volcano", GSA Bulletin; May 2011; v. 123; no. 5-6; p. 1193-1215