“Yes; all the rays of light which fall upon our mirror, gradually drawn together to where they form an image of the sun. It is only dull, my boy, but so far finely perfect, and we can say that we have gone on very successfully.”
As he spoke he laid the mirror down upon its back.
“Is that all you are going to do?” asked Tom.
“Yes; I can test it no better till it is more advanced, my boy. It may seem a little thing to you, but it is enough to show me that we may go on, and not begin our work all over again. Now for a good turn until breakfast-time. Two good hours’ work ought to produce some effect.”
The lower disc, now become convex, was wetted and lightly touched over with number five emery, which seemed soft enough for anything; the well-advanced mirror was turned over upon it, fitting now very closely, and with the sweet morning air floating in from the pine-woods, and the birds singing all around, the monotonous task went on with its intermissions till Uncle Richard gave the final wash off, and said—“Breakfast!”
They were so far advanced now that Tom was as eager to recommence as his uncle, and by that evening so much progress had been made that the setting sun was made to shine in upon it, to be reflected back in a bright spot on the wall without the aid of water; while two evenings later, when the great round glass was stood all dry the polish upon it was limpid, and seemed to be as pure as could be. There was not the faintest scratch visible, and Tom cried in triumph—
“There, now it is done! Oh, uncle, it is grand!”
“Grand enough so far, my boy. We have succeeded almost beyond my expectations; but that is only the first stage.”
“First—stage?” faltered Tom, looking at his uncle aghast.
“Yes, boy; we have succeeded in making a beautiful spherical concave mirror, which could be of no use whatever for my purpose.”