er flow, which secures steadiness, but sets economy at naught."

"It would be a good thing," said the young fellow, interrupting him, "if
some person would invent a burner that should heat the gas before its
discharge. We could then get a perfect combustion of the carbon, and so
greater brilliancy and economy."

"That is a very common error. Mr. Leslie's burner was designed on that
very theory: the result was contrary to expectation."

"What was the form of the burner?" inquired our host.

"Leslie's burner is a form of the argand. The gas, instead of issuing
from holes pierced in a solid ring, is conducted to the flame in
separate small tubes upward of an inch long. Twenty-eight of these tubes
are inserted in a ring two inches in diameter, and converge to one inch
at the ends, where the gas escapes. These tubes become hot very quickly
when the gas is lighted, and it issues at a high temperature. Here is
the result of a test made by Mr. Clegg, and given on page 344 of his
valuable work on coal gas:

COMMON ARGAND, FIFTEEN HOLES.
Consumption per hour in cubic feet:
6 feet, light = 17.4 standard candles.
5 feet, light = 13.64 standard candles

LESLIE'S BURNER, TWENTY-EIGHT HOLES.
6 feet, light = 14.73 standard candles.
5 feet, light = 11.28 standard candles.

"In experimenting with common burners, argand and others, it is found
that, if the aperture in the tip is too small for the orifice in the
body of the burner, the escaping gas is too highly heated and is
consumed too quickly. So with Leslie's burner in an increased degree.
Theories brought to the test of experiment are often disappointing."

The chemist now proceeded to illustrate his harangue with the argand
upon the table, which he lighted and turned on full, without replacing
the chimney. The dull-red flame streamed up to a height of eight inches
or more, waving and smoking slightly. He now turned down the gas and
replaced the chimney, then set the tap at the same angle as before.
"Here," said he, "we have a flame barely four inches high--of brilliant
white--which gives more light than the taller flame did. The cause of
the shortening of the flame is the more rapid combustion of the gas,
owing to the increased draught or air-supply in the chimney. From the
greater intensity of this flame a much larger quantity of light is
produced than by the longer flame. If too tall a chimney is used, the
flame is shortened st