Peckston’s Theory and Practice of Gas-lighting. 455 
plying them.—VIII. Purification of coal-gas; comparison be- 
tween the apparatus for this purpose as originally constructed, 
and the improved machinery lately adopted ; test apparatus for 
certifying the purity of coal-gas and the proper manner of work- 
ing the lime-machine ; best method of preparing the quick-lime. 
—IX. Account of the various improved gas-holders which have 
been invented and are now in action; gas-holder with governor or 
regulating gauge ; revolving gas-holder; collapsing gas-holder ; 
reciprocating safety-valve, &c.—X. Description of the gas-meter 
(an entirely new machine) lately adopted at the Birmingham, 
Chester and other gas-works, which measures and registers the 
quantity of gas manufactured in any given time from any given 
quantity of coal, or consumed during any period by any number 
of burners or lamps; great services of this machine both to the 
manufacturer and consumer of gas; to the manufacturer, by 
serving as a complete check on his workmen as to the quantity 
of work that ought to be performed, —and to the consumer, as an 
exact measure of the quantity of gas he receives and ought to 
pay for.—XI. Governor or gauge for regulating the pressure of 
the gas before it enters into the mains; directions to workmen 
for fixing it; application of this apparatus for regulating the 
magnitude of the flames of gas-burners and lamps.—XII. Gas- 
mains and branch-pipes ; rules to be observed for applying and 
distributing gas-pipes to the greatest advantage.—XIII. Most 
efficient mode of introducing gas to the interior of houses; in- 
structions to workmen for adapting the gas-pipes and insuring 
success at the least cost under every variety of circumstances.— 
XIV. Illuminating power of coal-gas ; quantity of gas consumed 
in a given ‘time by different kinds of gas-burners and lamps 5 
comparative cost of gas, tallow, and oil lights of different inten- 
sities; and most improved method for ventilating apartments 
lighted by gas— XV. Account of the manufacture of gas from 
coal tar, vegetable tar, and oil—And, XVI. Other preducts ob- 
tainable from coal; viz. coal tar, coal oil, pitch, ammoniacal li- 
quor ; manufacture of carbonate of ammonia and muriate of am- 
monia from the ammoniacal liquor ; London price list of the 
most essential articles in the manufacture and application of coal- 
gas. 
The plates, seven in number, are very elegantly coloured, and 
present sections, plans and elevations of all the most improved 
sorts of apparatus now employed at the Gas-works in London, 
and the principal provincial towns in Great Britain, 
The Theory and Practice of Gas-lighting, in which is exhibited 
a Historical Sketch of the Rise and Progress of the Science, 
and the Theories of Light, Combustion, and Formation of Coal ; 
Ff4 with 
