I have been unable to find out what "leads" in the quote below means. I hope some uk member will tell us.
"As this honour would have been an innovation and an experiment, Perch was fain to content himself by expressing as well as he could, in his manner, You are the light of my Eyes. You are the Breath of my Soul. You are the commander of the Faithful Perch! With this imperfect happiness to cheer him, he would shut the door softly, walk away on tiptoe, and leave his great chief to be stared at, through a dome-shaped window in the leads, by ugly chimney-pots and backs of houses, and especially by the bold window of a hair-cutting saloon on a first floor, where a waxen effigy, bald as a Mussulman in the morning, and covered after eleven o'clock in the day, with luxuriant hair and whiskers in the latest Christian fashion, showed him the wrong side of its head for ever."

is it leads? as in the lead (metal) strips used to hold together not just 'stained glass' but clear peiced glass panals as used in domed windows and skylights? what we today called leaded windows?
is a a dome-shaped window in the leads- a leaded glass dome shaped window?(WAG on my part)

Here's another quote using the word "leads":

The students of the sage's precepts, left to their own application of his wisdom upon a principle which was the main leg of the Bunsby tripod, as it is perchance of some other oracular stools--looked upon one another in a little uncertainty; while Rob the Grinder, who had taken the innocent freedom of peering in, and listening, through the skylight in the roof, came softly down from the leads...

I think 'the leads' is the roof, from the former practice of using lead sheeting for roofs.

Bingley