hine of Joseph Priestley. There are other
mementos of Newton--a stone graven with a sun-dial, which he carved as
a boy, on the paternal manor-house; a chair, said to have been his,
guarded here by a silk cord against profanation; bits of the famous
apple-tree which, as tradition will have it, aided so tangibly in
the greatest of discoveries; and the manuscript of the _Principia_
itself--done by the hand of an amanuensis, to be sure, but with
interlinear corrections in the small, clear script of the master-hand
itself. Here, too, is the famous death-mask, so much more interesting
than any sculptured portrait, and differing so strangely in its
broad-based nose and full, firm mouth from the over-refined lineaments
of the sculptured bust close at hand. In a room not far away, to reach
which one passes a score or two of portraits and as many busts of
celebrities--including, by-the-bye, both bust and portrait of Benjamin
Franklin--one finds a cabinet containing other mementos similar to those
on the library tables. Here is the first model of Davy's safety-lamp;
there a chronometer which aided Cook in his famous voyage round the
world. This is Wollaston's celebrated "Thimble Battery." It will slip
readily into the pocket, yet he jestingly showed it to a visitor as
"his entire laboratory." That is a model of the double-decked boat made
by Sir William Petty, and there beyond is a specimen of almost, if not
quite, the first radiometer devised by Sir William Crookes.

As one stands in the presence of all these priceless relics, so vividly
do the traditions of more than two centuries of science come to mind
that one seems almost to have lived through them. One recalls, as if it
were a personal recollection, the founding of the Royal Society itself
in 1662, and the extraordinary scenes which the society witnessed during
the years of its adolescence.

As one views the mementos of Boyle and Newton, one seems to be living in
the close of the seventeenth century. It is a troublous time in England.
Revolution has followed revolution. Commonwealth has supplanted monarchy
and monarchy commonwealth. At last the "glorious revolution" of 1688 has
placed a secure monarch on the throne. But now one external war follows
another, and the new king, William of Orange, is leading the "Grand
Alliance" against the French despot Louis XIV. There is war everywhere
in Europe, and the treaty of Ryswick, in 1697, is but the preparation
for the war of the