Evening star., 1901-01-18
The BOule Light.

paper read before the international Gas Congress
of Paris by Ernest SalZenberS of Crefeld.
Since DIR. Auer Won Welsbach placed the
third model of his burner upon the market
dn October, 1S9D and obtained the eff
cheney of two liters of gas consumed per
candle power, the general tendency of those
engaged on this question has been in the
direction of still further obtaining the heat
energy in the form of light. Two methods
have been followed. According to the first
of these methods special burners are pro-
vided in which a higher efficiency is OBJ
tanned by more perfect admiXture of the
gases. l may mention the first Denay-
rouze burner July, 1850, which works with
a rapidly rotating fan. Lewes obtained
with this, it would appear, 2oO-candle pow
er with 252 liters; and. in another burner,
1-candle power per 1.5 liters
In the burner of o. Kern, made in the
same year, with a pressure of from 45 to
800 nm. one could obtain 1-candle power
with a consumption of IA liters of gas or
even with less at pressure of 400 nm.
But this burner has never been introduced
into Germany. In the st. Paul burner the
gas is superheated and gives under pres
sures of 20, 152 and 200 nm. and gas con-
sumptions of 800 800 and $40 liters re-
spectively, 26J, 400 and G45 candle power
i.e., 132. 1.25 and 0.S liters per candle To
detail others would take up too much
space.
The second method sought to give the in
creased yield by raising the pressure of the
gas, and also of the air The connection
between increased pressure and greater
luminosity has already been dWelt upon.
In the year 1892 Fahndrich of Vienna
stated, In reference to the use of compressed
Pintsch gas at Strasburg. that high pres
sure meant a great amount of light; and
he predicted that the Wesbach burner
would, in course of time, attain from 300
to 800 candle power. In the same year
Herr Won Oechelhaeuser stated, in his report
to the Industrial Association at Berlin that
every millimeter of pressure over and above
the normal corresponded to an increase of
about 1-candle power.
The color of the light is more similar to
sunlight than the blush color Of the electric
arc the greenish tint of the Welsbach
burner. The uniform distribution gives a
wonderful absence of shadow compared
with that observable in the case of an arc
lamp, insomuch as friend of niine-a pro-
fessor in the High School at Charlotten-
burg-has wittily named my light ia
lumiere de Pierre Schmeil,' 1.-The man
without a shadow" after one of the we'll
known stories of the French poet, Adal-
bert de Chamisso.
There is. of course, divided opinion as to
which is the best coior for light Some
prefer white light in (say) shops, etc. but
the general preference is for a yellowish
light especially since it has been shown by
Professor Hempel that white light exerts
stronger chemical action on the purple Of
the retina, and is therefore more fatiguing
to the eyes. DR.. Bunte, who has made
number of photometric and spectro-photo-
metric tests of this ana other incandescent
lights, concludes as follows: % Compress
sion to IL atmospheres is very economical
in gas. (2) The distribution Of the light at
this pressure is much more uniform than
in ordinary incandescent systems CD The
light is of an agreeable yellowish color re-
Sembling sunlight, and the efficiency OF the
burners is very high. r