furnished with a deep hood and a shelf, as
if Tommy had been expected to devote his leisure hours to the
cultivation of mignonette.

"See now!"

And the burly lecturer pointed impressively to a laborer at this moment
approaching with a large lighted lantern in each hand. These, placed
upon the mignonette shelves, and snugly protected from wind and rain by
the deep hoods, threw a clear light into the test-room, and brought out
in grotesque distinctness the arabesque pattern wrought with dust and
oil upon Tommy's broad visage.

"And that's how we gits light, Sir," remarked the professor, in
conclusion, as, with a dignified salutation of farewell, he disappeared
in the still-house.

Admonished by the lanterns and the fading glory of the west, Miselle and
her host now bent their steps homeward, deferring, like Scheherezade,
"still finer and more wonderful stories until the next morning."

At their next visit to the Refinery, the visitors were committed to a
little wiry old man, called Jimmy, who first showed them a grewsome
monster, own cousin to him who threw oil from Tarr Farm to Plummer. This
one was called an air-pump, and, with his attendant steam-engine,
inhabited a house by himself. His work will presently be explained.

The next building was the treating-house, where stand huge tanks
containing the oil as drawn from the testing-room. From these it is
conducted by pipes to the iron vats, called treating-tanks, and there
mixed with vitriol, alkali, and other chemicals, in certain exact
proportions. The monster in the next building is now set in operation,
and forces a stream of compressed air through a pipe from top to bottom
of the tank, whence, following its natural law, it loses no time in
ascending to the surface with a noisy ebullition, just like, as Jimmy
remarked, "a big pot over a sthrong fire."

This mixing operation was formerly performed by hand in a much less
effectual manner, the steam air-pump being a recent improvement.

The work of the chemicals accomplished, the oil is cleansed of them by
the introduction of water, and after an interval of quiet the mass
separates so thoroughly that the water and chemicals can be drawn off at
the bottom of the vat with very little disturbance to the oil.

From the treating-house the perfected oil is drawn to the tanks of the
barrelling-shed, and filled into casks ready for exportation. A large
cooper's shop upon the premises supplies a portion of the barrel