il?" inquired Mr. Williams,
carelessly.

The fat man gave him a look of solemn indignation, and proceeded without
heeding the interruption.

"Whin I joodge, Ma'am, that the binzole is nigh run out, I tist it with
a hyder-rometer, this a-way."

And Tommy, descending from the stool, took from the shelf first a tin
pot strongly resembling a shaving-mug, and then a little glass
instrument, with a tube divided into sections by numbered lines, and a
bulb half filled with quick-silver at the base.

Filling the shaving-mug with oil, the lecturer dropped into it his
hydrometer, which, after gracefully dancing up and down for a moment,
remained stationary.

"It's at 55 deg. you'll find it. Look for yersilf, Ma'am," he resumed,
with the serene confidence of the prestidigitateur who informs the
audience that the missing handkerchief will be found in "that
gentleman's pocket."

Miselle examined the figures at high-oil mark, and found that they were
actually 55 deg.

"The binzole, you see, Ma'am, is so thin that the hyder-rometer drops
right down over head an' ears in it; but as it gits to be ile, it comes
heavier an' stouter, an' kind uv buoys it up, until at lin'th an' at
last the 60 deg. line comes crapin' up in sight. Thin I thry it by the
fire tist. I puts some in a pan over a sperit-lamp, and keep a-thryin'
an' a-thryin' it wid a thermometer; an' whin it's 'most a-bilin', I
puts a lighted match to the ile, an' if it blazes, there's still too much
binzole, an' I lets it run a bit longer. But if all's right, I cuts off
the binzole, and the nixt run is ile sech as you see it. The longer it
runs, the heavier it grows; and whin it gits so that the hyder-rometer
stands at 42 deg., I cuts off agin. Thin the next run is heavy ile, thick
and yaller, and that doesn't come in here at all, but is drawn from the
still, and mixed wid crude ile, and stilled over agin; and whin no more
good's to be got uv it, it's mighty good along wid the binzole to keep
the pot a-bilin' in beyant."

"You don't use the fire test in this building, I presume, do you?"

"Indade, no, Ma'am. There's niver a light nor yit a lanthern allowed
here."

"But you run all night. How do you get light in this room?" inquired Mr.
Williams.

"From widout. Did niver ye mind the windys uv this house?"

And the professor, dismounting from his stool, led the way to the
outside of the building, where he pointed to two picturesque little
windows near the roof, each