that means are provided for supplying a sufficient quantity of air for
admixture with the gas before it reaches the flame. The air is admitted
through a number of holes or slits opening into the tube through which
the gas passes, and in rushing forward under pressure the gas draws the
air with it into the flame. To realise a maximum amount of heat out
of a given quantity of gas, it is necessary to add to it a definite
proportion of air. When the gas rushes rapidly towards the flame, a
greater quantity of air is drawn in through the orifices provided for
that purpose than when the gas passes more slowly. This to a certain
extent regulates the supply of air; but it sometimes happens that too
much or too little air is admitted. A small quantity of gas passing
through the pipe cannot exercise the force necessary to create a
partial vacuum into which the air would be drawn, and as a consequence,
the heat derived from the flame is far below what might be expected—in
short, it ceases wholly or partially to be a blue flame, and becomes
a luminous and comparatively cold, or perhaps a smoky one. The other
provision is made for the proper control of the supply of air; and
since an excess is the lesser of the two evils, it is wiser to adopt
the precaution of having holes or slits in the pipe large enough to
admit a sufficient quantity of air. The larger the oven or roaster, the
more convenient it will be. This oven should be provided with movable
‘grids’ or trays, and should have one metal tray for the reflection of
heat, by which the tops of pies, &c., may be browned; and also with
a ventilator, to allow the gases to escape. A gas-stove with a small
oven, or with one divided into a number of parts without the means of
being enlarged, will be found very inconvenient if it is required to
roast a large joint.
A BUTTERFLY IN THE CITY.
Fair creature of a few short sunny hours,
Sweet guileless fay,
Whence flittest thou, from what bright world of flowers,
This summer day?
What quiet Eden of melodious song,
What wild retreat,
Desertest thou for this impatient throng,
This crowded street?
Why didst thou quit thy comrades of the grove
And meadows green?
What Fate untoward urges thee to rove
Through this strange scene?
Have nectared roses lost their power to gain
Thy fond caress?
Do woodbine blooms, with lofty scorn, disdain
Thy loveliness?
Oh, hie thee to the fragrant country air
And liberty!
The city is the home of toil and care—
No place for thee!
EDWIN C. SMALES.
* * * * *
Printed and Published by W. & R. CHAMBERS, 47 Paternoster Row, LONDON,
and 339 High Street, EDINBURGH.
* * * * *
_All Rights Reserved._
* * * * *
[Transcriber’s Note—the following changes have been made to this text.
Page 357: boycoted to boycotted—“picketed and boycotted”.]