He considers the achromatic telescope the king of instruments, and is now engaged in testing convex optical surfaces, with a view to achieving a telescope of that description.

The chief difficulty is the heavy charge for the circular blocks of flint glass requisite for the work which he meditates.

"That," he says, "is the great difficulty with amateurs of my class." He has, however, already contrived and constructed a machine for grinding and polishing the lenses in an accurate convex form, and it works quite satisfactorily.
Mr.Lancaster makes his own tools.

From the raw material, whether of glass or steel, he produces the work required.

As to tools, all that he requires is a bar of steel and fire; his fertile brain and busy hands do the rest.