I would ask all who have seen a torchlight procession to recall the sensation, as closely as they can, when the first burst of torchlight came upon them, for that is the moment I have attempted to fix upon my canvas; and those who have not seen a large crowd under these conditions may imagine what it would be like by the aid of fire or torchlights which they have seen at other times. I would ask you to exercise the faculties of memory or imagination while I give you a brief description of the emotions it roused in my mind as one of the many thousand spectators, and the effect it had upon my seeing faculties, which will enable you to comprehend my motives for working as I did, preferring the _strict reality_ of the instantaneous phase or impression to the _actuality_ of the known form. (This I give you, not as an apology or explanation for my picture, but as the nearest illustration I can think about, at present, of one of the phenomenal laws of lighting.) We were standing upon a house roof, looking over the city. Right and left lay Princes Street, with the Mound at our feet, and Scott's Monument in the middle distance. Most of the time we were in darkness, with the exception of one or two straggling candles at windows here and there, at wide intervals. A mellow glow at the south end of the North Bridge, a blue light behind the Monument, an occasional rocket fizzing from Calton Hill, also faintly illumined with white and blue fire, into the umber-tinted darkness of that starless, cloud-bulging sky, and the alternating glaring from Hanover Street of rose-coloured, white, and green lights, which dyed the upturned faces of the crowd and the columns of the Institution in a broad line with the scarlet or emerald colour of the fire then burning, for a few pulsating moments of eye-nerve-straining. Then fell a deeper wave of darkness as the light passed from us, rushing over the heaving masses below, whence rose up that sympathetic thrilling sound which ever grips and holds the hearts of a crowd like one heart, and over the houses, with their lights dashed out for a moment by the passing away of that more intense light, all preparing me for the fantastic sight we were awaiting.