oles which come
together at the top, so that the two jets of gas impinge and form a flat
flame; in the batwing the gas issues in a thin sheet through a slit in a
hollow knob; while in the argand the gas enters a short cylinder or
broad ring, escaping thence through numerous holes at the upper edge.
There are many varieties of each of these, differing in the construction
of the part below the tip. The argand has long been the favorite burner
for the table and desk. Its advantages are a strong, steady light, but,
as you know, it is apt to smoke at every slight increase in the pressure
of the gas, though there are recent improved forms in which this fault
is in a measure corrected. A properly-made argand burner will give a
light equal to three whole candles (spermaceti, of the standard size and
quality) for every foot of gas burned. Of the argand burners, Guise's
shadowless argand has been considered the best, but of late years Sugg's
Letheby burner has carried off the palm. Wood's burner has been a
favorite, as, being a fishtail, it could be used with a short chimney,
which gives the flame steadiness. By the arms on the chimney-frame the
flame is broadened at the bottom, with a smaller dark space at the base
than in any other flat-flame burner. It is so constructed that the
quantity of gas passing is regulated by turning a tap in the lower part
of the burner, which changes the size of the orifice in the tube. Ten
years ago this burner, with a regulator at the meter, was generally
thought to be the most economical contrivance possible. It is now little
used. Yet either the batwing or the fishtail tip can be used in any
common burner except the argand. The old brass and iron tips are mostly
superseded by those of "lava," being liable to an early change of the
orifice from incrustation and rust. In the flat-flame burners there are
differences in the internal arrangement. Perhaps our young
gas-manufacturer here can tell us what is now the most approved burner."

The young man confessed that he had specimens of the best kinds of
flat-flame burners in his pocket. He quickly brought from his overcoat
in the hall a small paper parcel from which he produced several bright
little brass tubes, explaining that he carried them because somebody was
always inquiring about the best kind of burner. "These save talk," said
he.

With a small wrench he removed one of the old burners, and the several
kinds were successively tested in its pla