"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."

"Then why did we make it?" cried Tom. "For practice?"

"No, boy; because it is the step towards making an ellipse, or, as they call it when shaped for a reflecting telescope, a parabola. You know what an ellipse is?"

"Gooseberry," said Tom bluntly.

"Gooseberry-shaped," said his uncle. "Well then, what is a parabola?"

"One of those things we used to learn about in geometry."

"Good. Well, to-morrow we must begin polishing, or rather I must, to turn our gla.s.s from a spherical-curved mirror into a parabola."

"You'll let me help, uncle?"

"As much as I can, my boy; but the amount I have to polish off, in what is called figuring, is so small that it requires the most delicate of treatment, and first of all we have to prepare a small polisher to work by hand."

This was formed of lead in the course of the next day--a nearly flat but slightly convex disc, with a handle upon its back, and when made perfectly smooth it was covered with hot pitch, which, as it cooled, was made to take the exact curve of the nearly finished mirror, by being pressed upon it, the pitch yielding sufficiently for the purpose.

This done the pitch was scored across and across, till it was divided into squares, with little channels between them, so that the polishing powder and water might run freely between; then a final pressure was given upon the mirror and the implement was left to harden till the next day.

"Now for a few hours' polishing," said Uncle Richard the next morning, as he took up the curved pitch tool and moistened it, no longer with emery, but with fine moistened rouge; "and if I am successful in slightly graduating off the sides here, and flattening them in an infinitesimal degree, we shall have a good reflector for our future work."

But upon testing it the result that evening was not considered satisfactory. There were several zones to be corrected.

It was the same the next day, and the next. But on the fourth Uncle Richard cried "Hold: enough! I think that is as good as an amateur can make a speculum, and we'll be content."

That night Tom slept so soundly that he did not dream till morning, and then it was of the sun resenting being looked at, and burning his cheek, which possessed some fact, for the blind was a little drawn on one side, and the bright rays were full upon his face.

"All that time spent in making the reflector!" thought Tom; "and all that work. I wonder what the next bit will be."

CHAPTER SIXTEEN.

"Now, uncle, what's the next thing to be done?" said Tom at breakfast that morning.

"I think we may begin the body of the telescope now, Tom," said his uncle.

"The body?"

"Yes; the speculum is what we might call the life of the whole instrument, and the rest will be simplicity itself. We've got to bring a little mechanical work to bear, and the thing is done."

"But it will want a lot of gla.s.ses fixed about in a big tube, won't it?"

"No; nothing but the flat and eye-pieces, and I have the lenses to make these. By the way, I have some letters to write, and shall be busy all the morning. Your uncle seems to be still unwell, and I must write to him, for one thing. I tell you what I want done. We have no place there for keeping papers or drawings in, and where one can sit down and write at times, and lock up afterwards. I've been thinking that I'll have the big old bureau desk with its drawers taken out of the study, and carried up into the laboratory. It can stand beneath the shelves on the right of the east window; and you might take up a chair or two, and a piece of old carpet as well. Get David to help you."

"All right, uncle."

So when breakfast was over, Tom went out and found David, who was sticking stakes along the outside of the asparagus bed, and tying tarred twine from one to the other, so as to keep the plume-like stems from blowing about and breaking.

"Mornin', Master Tom," he said. "I say, my Maria Louisas are swelling out fast. We shall soon have to be on the look-out for pear-ketchers."

"All right, David, I'll help you. I hope it is Pete Warboys. I should like to give him stick."

"We'll give him stake instead, Master Tom."

"Never mind that now. I want you to help me move that chest of drawers and desk out of uncle's study to the laboratory."

"Very good, sir; but you might call a spade a spade."

"What do you mean?" said Tom, staring.

"Labor hatory, sir! why don't you say windmill?"

"Because it has been made into an observatory, laboratory, and workshop all in one," said Tom, rather stiffly.

"Just as you like, Master Tom; but you may take the sails off, and the fan, and put all the rattle-traps in it you like, but it can't make it anything but what it was born to be, and that was a windmill."

"Well, we won't argue," said Tom. "Come along."

He led the way to the study, where Uncle Richard was seated at a table writing, and it being a particularly dry day, David spent about five minutes wiping nothing off his shoes on every mat he pa.s.sed, to Tom's great amus.e.m.e.nt. Then after making a bow and a sc.r.a.pe to his master which were not seen, he gave his nose a rub with his cuff, and went back to put his hat outside the door.

"Come along, David," said Tom. "This is it."

The gardener went on tiptoe to the end of the old escritoire, stooped, lifted it, and shook his head.

"You can't manage one end o' that, Master Tom," he said in a hoa.r.s.e whisper.

"No, too weighty," said his master; and without looking round he pa.s.sed his keys. "Take out the drawers, they're heavy, and carry them separately."

This plan was followed out, each taking a drawer and carrying it out through the garden, and across the lane to the yard gate, which Tom unlocked after resting his drawer on the wall; leaving it there while he ran up and unlocked the tower door, then going back for the load he had left.

These two drawers were carried into the stone-floored workshop, where the bench under the window was covered with an old blanket, another doing duty as cover for the gla.s.s tool which had been replaced on the head of the cask.

"My word! what a differ there is here," said David, as he glanced round with the drawer in his hands. "What yer put to bed under they blankets, sir?"

"Specula, David."

"Speckle-hay? What, are you forcing on 'em?"

"Forcing?" said Tom, laughing.

"Yes; are they coming up?"

"Nonsense! Here are those two great pieces of gla.s.s uncle brought down.