Part 54 (1/2)

”Exactly; but hoould you do that?”

”Oh, it's easy enough, I believe,” said Toet a sheet of tinfoil, lay it on a table, cover it with quicksilver, and then put the glass on it, and press it eights till the tinfoil and quicksilver stick to the glass, and then you have a regular mirror”

”You seem to know all about it, Tom,” said the Vicar, who had dropped in for a chat, and to hear how the telescope was going on

”I read it somewhere,” said To,” said his uncle; ”but never could re to do with the law”

Tom looked at him reproachfully

”Well,” continued Uncle Richard, ”your process would do for ordinary looking-glasses, Tom, but not for an optical reflector”

”Why, uncle?”

”Because the rays of light would have to pass through the thickness of the glass before they reached the reflecting surface,--the quicksilver,--and in so doing they would be refracted--broken-up and discoloured--so that the reflection would most likely be doubled when it came away; that is, you would see one reflection from the silver at the back, and another frolass”

”Therefore,” said the Vicar, ”we enious proposal, and take yours, Brandon, for as usual you have a plan ready”

”Well, yes,” said Uncle Richard, slass, but on the surface, so as to get a reflection at once Are you going to stay, Maxted?”

”If I may,” was the reply

”Very well; but for experiment, as it is all new to me, I think ill try first to silver one of these pieces of the broken speculuest piece”

The conversation took place in the workshop, and the triangular piece of glass having been brought out, it was first thoroughly washed, and rinsed with rain-water, and then further cleaned by rubbing it ith a strong acid, so as to burn off any i in clear rain-water it was declared by Uncle Richard to be che to be chemically as well as oing to stand here without asking questions if you don't, Master Tolass be chemically clean?”

”So that the silver may adhere to it,” said Uncle Richard, as now carefully arranging the freshly-cleaned glass, so that it lay on two pieces of wood in a shallow tray half full of water

”My turn to question,” said Too on,” said the Vicar

”Why is the face of the glass put in water, uncle?”

”To keep it wet and thoroughly clean Dust or floating spores ht settle upon it, and then we should have specks I want to get a surface perfectly clear; and now, Tom, I want the four bottles I prepared yesterday--fetch theht down four great stoppered bottles, each of which bore a label duly lettered

These he placed on the broad, table-like bench, and on being requested hurried up-stairs again to fetch a large glass jar-shaped vessel, and a graduated lass

”Now,” said Uncle Richard, ”this process is a cheood as a conjuring trick, and a very grand one too In fact it is good enough for a ician, for it is a wonderful example of the way in which our chemists have mastered some of the secrets of Nature”

”Bravo, lecturer!” said the Vicar ”Coive him some applause Clap your hands and sta his umbrella upon the floor

”Oh, very well,” said Uncle Richard, laughing; ”it shall be a lecture on silver if you like--a very brief one, with a remarkable experiment to follow”

”More applause, Toly