Telescope mirrors are polished and silvered in an underground factory in Coulsdon, Surrey.
M/S of a rather bleak looking stretch of countryside in Coulsdon, Surrey, with some spindly trees seen against a grey sky. M/Ss of a large ditch and then the entrance to some kind of underground shelter in the side of the hill. M/S of a grey car, a Standard Vanguard, driving along and pulling up at the entrance. John Thompson gets out and opens the rear door; he takes out a large circular glass and carries it through the entrance. Commentator talks, tongue in cheek, of a top secret underground rendezvous and the music on the soundtrack adds to the suspense.
M/Ss inside the darkly-lit shelter as John enters carrying the glass on his shoulder and walks to a workshop area where another man is working. We are told that this is a factory, and the work carried out here is so precise that a constant temperature is necessary, which is what this shelter has in winter and summer. As John places the glass down on a workbench and starts to apply some cleaning fluid, we learn that these men are from a Surrey firm that makes telescopes, and the large glass is a mirror.
John places a circular polishing device over the mirror and switches on a motor; we see polishing in C/U. Frederick Hargreaves is seen at another polishing machine as it works on another 20 inch mirror; he stops the machine to examine the mirror with a magnifying glass, then reapplies cleaning fluid and starts it up again.
M/Ss and C/Us of John adding the silver compound to the polished glass: he pours some liquid over the glass, which has a paper casing around it, then tips it into a sink and rinses it with water. He holds the mirror up so we can see his reflection in it. Commentator goes all poetic, saying "Mirrors like these reflect the dreams of all those who look to the heavens for the future of mankind".
Note: There are notes (a bit confusing and difficult to read) on file on the processes seen, plus a small news article.
Note: See out takes on *PM0125* CP 312 CUTS