eat
progress in cutting the crust (Ridgways) or alabaster, and also cut
marble, but the harder sorts soon blunt them. At any rate, marble does
not do for the medallions, as its grain prevents its being cut smooth,
and its semi-transparence hurts the effect. I think Bristol lime, or
shell lime, pressed in your manner, would have a good effect. When you
are at leisure, I shall thank you for a few pieces, and if some of them
are made pink or flesh colour, they will look well. I used the ball
quite perpendicular, and it cut well, as most of the cutting is
sideways. I tried a fine whirling point, but it made little progress;
another with a chisel edge did almost as well as the balls, but did not
work so pleasantly. I find a triangular scraping point the best, and I
think from some trials it should be quite a sharp point. The wheel
runs easier than it did, but has still too much friction. I wished to
have had an hour's consultation with you, but have been prevented by
sundry matters among others by that plaguey stove, which is now in your
hands."

Watt was most grateful to Murdock for his unvarying assistance. In
January, 1813, when Watt was in his seventy-seventh year, he wrote to
Murdock, asking him to accept a present of a lathe "I have not heard
from you," he says, "in reply to my letter about the lathe; and,
presuming you are not otherwise provided, I have bought it, and request
your acceptance of it. At present, an alteration for the better is
making in the oval chuck, and a few additional chucks, rest, etc., are
making to the lathe. When these are finished, I shall have it at
Billinger's until you return, or as you otherwise direct. I am going
on with my drawings for a complete machine, and shall be glad to see
you here to judge of them."

The drawings were made, but the machine was never finished.
"Invention," said Watt, "goes on very slowly with me now." Four years
later, he was still at work; but death put a stop to his
"diminishing-machine." It is a remarkable testimony to the skill and
perseverance of a man who had already accomplished so much, that it is
almost his only unfinished work. Watt died in 1819, in the
eighty-third year of his age, to the great grief of Murdock, his oldest
and most attached friend and correspondent.

Meanwhile, the firm of Boulton and Watt continued. The sons of the two
partners carried it on, with Murdock as their Mentor. He was still
full of work and inventive power