ever; but how he flashed out with utter merriment when he
got hold of a joke, or rather when it got hold of him, and
shook him, not an inch of his body was free of its power--it
possessed him, not he it. The first attack was on showing me
a calotype of himself by the late Adamson (of Hill and
Adamson; the Vandyke and Raeburn of photography), in the
corner of which he had written, with a hand trembling with
age and fun, "Adam's-sun _fecit_"--it came back upon him and
tore him without mercy.

Then, his blood being up, he told me a story of his uncle,
the great Dr. Black the chemist; no one will grudge the
reading of it in my imperfect record, though it is to the
reality what reading music is to hearing it.

Dr. Black, when Professor of Chemistry in Edinburgh
University, had a gruff old man as his porter, a James
Alston. James was one of the old school of chemistry, and
held by phlogiston, but for no better reason than the
endless trouble the new-fangled discoveries brought upon him
in the way of apparatus.

The Professor was lecturing on Hydrogen Gas, and had made
arrangements for showing its lightness, what our preceptor,
Dr. Charles Hope, called, in his lofty way, its "principle
of absolute levity." He was greatly excited, the good old
man of genius. James was standing behind his chair, ready
and sulky. His master told his young friends that the
bladder he had filled with the gas must, on principle,
ascend; but that they would see practically if it did, and
he cut the string. Up it rushed, amid the shouts and
upturned faces of the boys, and the quiet joy of their
master; James regarding it with a glum curiosity.

Young Adam Ferguson was there, and left at the end of the
hour with the rest, but finding he had forgotten his stick,
went back; in the empty room, he found James perched upon a
lofty and shaky ladder, trying, amid much perspiration, and
blasphemy, and want of breath, to hit down his enemy, who
rose at each stroke--the old battling with the new. Sir
Adam's reproduction of this scene, his voice and screams of
rapture, I shall never forget.

Let me give another pleasant story of Dr. Black and Sir